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  • PEBP1/RKIP behavior: a mirror of actin-membrane organization
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-20
    Françoise Schoentgen, Slavica Jonic

    Abstract Phosphatidylethanolamine-binding protein 1 (PEBP1), a small 21 kDa protein, is implicated in several key processes of the living cell. The deregulation of PEBP1, especially its downregulation, leads to major diseases such as cancer and Alzheimer’s disease. PEBP1 was found to interact with numerous proteins, especially kinases and GTPases, generally inhibiting their activity. To understand the basic functionality of this amazing small protein, we have considered several known processes that it modulates and we have discussed the role of each molecular target in these processes. Here, we propose that cortical actin organization, associated with membrane changes, is involved in the majority of the processes modulated by PEBP1. Furthermore, based on recent data, we summarize some key PEBP1-interacting proteins, and we report their respective functions and focus on their relationships with actin organization. We suggest that, depending on the cell status and environment, PEBP1 is an organizer of the actin-membrane composite material.

  • Loss of function in the Drosophila clock gene period results in altered intermediary lipid metabolism and increased susceptibility to starvation
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-20
    Stefan Schäbler, Kelechi M. Amatobi, Melanie Horn, Dirk Rieger, Charlotte Helfrich-Förster, Martin J. Mueller, Christian Wegener, Agnes Fekete

    Abstract The fruit fly Drosophila is a prime model in circadian research, but still little is known about its circadian regulation of metabolism. Daily rhythmicity in levels of several metabolites has been found, but knowledge about hydrophobic metabolites is limited. We here compared metabolite levels including lipids between period01 (per01) clock mutants and Canton-S wildtype (WTCS) flies in an isogenic and non-isogenic background using LC–MS. In the non-isogenic background, metabolites with differing levels comprised essential amino acids, kynurenines, pterinates, glycero(phospho)lipids, and fatty acid esters. Notably, detectable diacylglycerols (DAG) and acylcarnitines (AC), involved in lipid metabolism, showed lower levels in per01 mutants. Most of these differences disappeared in the isogenic background, yet the level differences for AC as well as DAG were consistent for fly bodies. AC levels were dependent on the time of day in WTCS in phase with food consumption under LD conditions, while DAGs showed weak daily oscillations. Two short-chain ACs continued to cycle even in constant darkness. per01 mutants in LD showed no or very weak diel AC oscillations out of phase with feeding activity. The low levels of DAGs and ACs in per01 did not correlate with lower total food consumption, body mass or weight. Clock mutant flies showed higher sensitivity to starvation independent of their background-dependent activity level. Our results suggest that neither feeding, energy storage nor mobilisation is significantly affected in per01 mutants, but point towards impaired mitochondrial activity, supported by upregulation of the mitochondrial stress marker 4EBP in the clock mutants.

  • Deciphering the neuroprotective and neurogenic potential of soluble amyloid precursor protein alpha (sAPPα)
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-20
    Nawab John Dar, Gordon W. Glazner

    Abstract Amyloid precursor protein (APP) is a transmembrane protein expressed largely within the central nervous system. Upon cleavage, it does not produce the toxic amyloid peptide (Aβ) only, which is involved in neurodegenerative progressions but via a non-amyloidogenic pathway it is metabolized to produce a soluble fragment (sAPPα) through α-secretase. While a lot of studies are focusing on the role played by APP in the pathogenesis of Alzheimer’s disease, sAPPα is reported to have numerous neuroprotective effects and it is being suggested as a candidate with possible therapeutic potential against Alzheimer’s disease. However, the mechanisms through which sAPPα precisely works remain elusive. We have presented a comprehensive review of how sAPPα is regulating the neuroprotective effects in different biological models. Moreover, we have focused on the role of sAPPα during different developmental stages of the brain, neurogenic microenvironment in the brain and how this metabolite of APP is regulating the neurogenesis which is regarded as a compelling approach to ameliorate the impaired learning and memory deficits in dementia and diseases like Alzheimer’s disease. sAPPα exerts beneficial physiological, biochemical and behavioral effects mitigating the detrimental effects of neurotoxic compounds. It has shown to increase the proliferation rate of numerous cell types and promised the synaptogenesis, neurite outgrowth, cell survival and cell adhesion. Taken together, we believe that further studies are warranted to investigate the exact mechanism of action so that sAPPα could be developed as a novel therapeutic target against neuronal deficits.

  • Epigenetic histone modulation contributes to improvements in inflammatory bowel disease via EBI3
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-18
    Alexandra Wetzel, Bettina Scholtka, Christian Gerecke, Burkhard Kleuser

    Abstract Ulcerative colitis (UC) is characterized by relapsing–remitting inflammatory episodes paralleled by varying cytokine levels, suggesting that switching epigenetic processes might be involved. However, the epigenetic impact on cytokine levels in colitis is mostly unexplored. The heterodimeric interleukin (IL)-12 cytokine family have various functions in both pro- and anti-inflammatory processes. The family member IL-35 (EBI3/IL-12p35) was recently reported to play an anti-inflammatory role in UC. Therefore, we aimed to investigate a possible epigenetic regulation of the IL-35 subunits in vitro and in vivo, and to examine the epigenetic targeting of EBI3 expression as a therapeutic option for UC. Exposure to either the pro-inflammatory TNFα or to histone deacetylase inhibitors (HDACi) significantly increased EBI3 expression in Human Colon Epithelial Cells (HCEC) generated from healthy tissue. When applied in combination, a drastic upregulation of EBI3 expression occurred, suggesting a synergistic mechanism. Consequently, IL-35 was increased as well. In vivo, the intestines of HDACi-treated wild-type mice exhibited reduced pathological signs of colitis compared to non-treated colitic mice. However, the improvement by HDACi treatment was completely lost in Ebi3-deficient mice (Ebi3−/−). In fact, HDACi appeared to exacerbate the disease phenotype in Ebi3−/−. In conclusion, our results reveal that under inflammatory conditions, EBI3 is upregulated by the epigenetic mechanism of histone acetylation. The in vivo data show that the deficiency of EBI3 plays a key role in colitis manifestation. Concordantly, our data suggest that conditions promoting histone acetylation, such as upon HDACi application, improve colitis by a mechanism involving the local formation of the anti-inflammatory cytokine IL-35.

  • Regulation of spermatogenesis and reproductive capacity by Igf3 in tilapia
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-18
    Minghui Li, Xingyong Liu, Shengfei Dai, Hesheng Xiao, Shuangshuang Qi, Yibing Li, Qiaoyuan Zheng, Mimi Jie, Christopher H. K. Cheng, Deshou Wang

    Abstract A novel insulin-like growth factor (igf3), which is exclusively expressed in the gonads, has been widely identified in fish species. Recent studies have indicated that Igf3 regulates spermatogonia proliferation and differentiation in zebrafish; however, detailed information on the role of this Igf needs further in vivo investigation. Here, using Nile tilapia (Oreochromis niloticus) as an animal model, we report that igf3 is required for spermatogenesis and reproduction. Knockout of igf3 by CRISPR/Cas9 severely inhibited spermatogonial proliferation and differentiation at 90 days after hatching, the time critical for meiosis initiation, and resulted in less spermatocytes in the mutants. Although spermatogenesis continued to occur later, more spermatocytes and less spermatids were observed in the igf3−/− testes when compared with wild type of testes at adults, indicating that Igf3 regulates spermatocyte to spermatid transition. Importantly, a significantly increased occurrence of apoptosis in spermatids was observed after loss of Igf3. Therefore, igf3−/− males were subfertile with drastically reduced semen volume and sperm count. Conversely, the overexpression of Igf3 in XY tilapia enhanced spermatogenesis leading to more spermatids and sperm count. Transcriptomic analysis revealed that the absence of Igf3 resulted in dysregulation of many genes involved in cell cycle, meiosis and pluripotency regulators that are critical for spermatogenesis. In addition, in vitro gonadal culture with 17α-methyltetosterone (MT) and 11-ketotestosterone (11-KT) administration and in vivo knockout of cyp11c1 demonstrated that igf3 expression is regulated by androgens, suggesting that Igf3 acts downstream of androgens in fish spermatogenesis. Notably, the igf3 knockout did not affect body growth, indicating that this Igf specifically functions in reproduction. Taken together, our data provide genetic evidence for fish igf3 in the regulation of reproductive capacity by controlling spermatogenesis.

  • Systems biology: current status and challenges
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-13
    Anze Zupanic, Hans C. Bernstein, Ines Heiland

    Abstract We put together a special issue on current approaches in systems biology with a focus on mathematical modeling of metabolic networks. Mathematical models have increasingly been used to unravel molecular mechanisms of complex dynamic biological processes. We here provide a short introduction into the topics covered in this special issue, highlighting current developments and challenges.

  • DNA-PK: gatekeeper for IKKγ/NEMO nucleocytoplasmic shuttling in genotoxic stress-induced NF-kappaB activation
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-13
    Senad Medunjanin, Maximilian Putzier, Till Nöthen, Sönke Weinert, Thilo Kähne, Blerim Luani, Werner Zuschratter, Ruediger C. Braun-Dullaeus

    Abstract The transcription factors of the nuclear factor κB (NF-κB) family play a pivotal role in the cellular response to DNA damage. Genotoxic stress-induced activation of NF-κB differs from the classical canonical pathway by shuttling of the NF-κB Essential Modifier (IKKγ/NEMO) subunit through the nucleus. Here, we show that DNA-dependent protein kinase (DNA-PK), an enzyme involved in DNA double-strand break (DSB) repair, triggers the phosphorylation of NEMO by genotoxic stress, thereby enabling shuttling of NEMO through the nucleus with subsequent NF-κB activation. We identified serine 43 of NEMO as a DNA-PK phosphorylation site and point mutation of this serine to alanine led to a complete block of NF-κB activation by ionizing radiation (IR). Blockade of DNA-PK by a specific shRNA or by DNA-PKcs-deficient cells abrogated NEMO entry into the nucleus, as well. Accordingly, SUMOylation of NEMO, a prerequisite of nuclear NEMO, was abolished. Based on these observations, we propose a model in which NEMO phosphorylation by DNA-PK provides the first step in the nucleocytoplasmic trafficking of NEMO.

  • GRK2 levels in myeloid cells modulate adipose-liver crosstalk in high fat diet-induced obesity
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-11
    Rocío Vila-Bedmar, Marta Cruces-Sande, Alba C. Arcones, Hanneke L. D. M. Willemen, Patricia Prieto, Isabel Moreno-Indias, Daniel Díaz-Rodríguez, Sara Francisco, Rafael I. Jaén, Carolina Gutiérrez-Repiso, Cobi J. Heijnen, Lisardo Boscá, Manuel Fresno, Annemieke Kavelaars, Federico Mayor, Cristina Murga

    Abstract Macrophages are key effector cells in obesity-associated inflammation. G protein-coupled receptor kinase 2 (GRK2) is highly expressed in different immune cell types. Using LysM-GRK2+/− mice, we uncover that a reduction of GRK2 levels in myeloid cells prevents the development of glucose intolerance and hyperglycemia after a high fat diet (HFD) through modulation of the macrophage pro-inflammatory profile. Low levels of myeloid GRK2 confer protection against hepatic insulin resistance, steatosis and inflammation. In adipose tissue, pro-inflammatory cytokines are reduced and insulin signaling is preserved. Macrophages from LysM-GRK2+/− mice secrete less pro-inflammatory cytokines when stimulated with lipopolysaccharide (LPS) and their conditioned media has a reduced pathological influence in cultured adipocytes or naïve bone marrow-derived macrophages. Our data indicate that reducing GRK2 levels in myeloid cells, by attenuating pro-inflammatory features of macrophages, has a relevant impact in adipose-liver crosstalk, thus preventing high fat diet-induced metabolic alterations.

  • The cannabinoid ligands SR141716A and AM251 enhance human and mouse islet function via GPR55-independent signalling
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-10
    Inmaculada Ruz-Maldonado, Bo Liu, Patricio Atanes, Attilio Pingitore, Guo Cai Huang, Pratik Choudhary, Shanta J. Persaud

    Abstract Aims Endocannabinoids are lipid mediators involved in the regulation of glucose homeostasis. They interact with the canonical cannabinoid receptors CB1 and CB2, and it is now apparent that some cannabinoid receptor ligands are also agonists at GPR55. Thus, CB1 antagonists such as SR141716A, also known as rimonabant, and AM251 act as GPR55 agonists in some cell types. The complex pharmacological properties of cannabinoids make it difficult to fully identify the relative importance of CB1 and GPR55 in the functional effects of SR141716A, and AM251. Here, we determine whether SR141716A and AM251 regulation of mouse and human islet function is through their action as GPR55 agonists. Methods Islets isolated from Gpr55+/+ and Gpr55−/− mice and human donors were incubated in the absence or presence of 10 µM SR141716A or AM251, concentrations that are known to activate GPR55. Insulin secretion, cAMP, IP1, apoptosis and β-cell proliferation were quantified by standard techniques. Results Our results provide the first evidence that SR141716A and AM251 are not GPR55 agonists in islets, as their effects are maintained in islets isolated from Gpr55−/− mice. Their signalling through Gq-coupled cascades to induce insulin secretion and human β-cell proliferation, and protect against apoptosis in vitro, indicate that they have direct beneficial effects on islet function. Conclusion These observations may be useful in directing development of peripherally restricted novel therapeutics that are structurally related to SR141716A and AM251, and which potentiate glucose-induced insulin secretion and stimulate β-cell proliferation.

  • Correction to: Molecular mechanism of olesoxime-mediated neuroprotection through targeting α-synuclein interaction with mitochondrial VDAC
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-09
    Amandine Rovini, Philip A. Gurnev, Alexandra Beilina, María Queralt-Martín, William Rosencrans, Mark R. Cookson, Sergey M. Bezrukov, Tatiana K. Rostovtseva

    In the published article, an error was noticed and this has been corrected with this erratum publication.

  • Correction to: Tet3 regulates cellular identity and DNA methylation in neural progenitor cells
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-09
    Mafalda Santiago, Claudia Antunes, Marta Guedes, Michelina Iacovino, Michael Kyba, Wolf Reik, Nuno Sousa, Luísa Pinto, Miguel R. Branco, C. Joana Marques

    The article Tet3 regulates cellular identity and DNA methylation in neural progenitor cells, written by Miguel R. Branco and C. Joana Marques, was originally published electronically on the publisher’s internet portal.

  • Retraction Note to: cGMP-phosphodiesterase 6, transducin and Wnt5a/Frizzled-2-signaling control cGMP and Ca 2+ homeostasis in melanoma cells
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-09
    Alexandr V. Bazhin, Vojtech Tambor, Boyan Dikov, Pavel P. Philippov, Dirk Schadendorf, Stefan B. Eichmüller

    The Editor-in-Chief has retracted this article [1] due to errors in Figs. 1b, c and 4.

  • Biased agonists at the human Y 1 receptor lead to prolonged membrane residency and extended receptor G protein interaction
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-09
    Anette Kaiser, Lizzy Wanka, Isabelle Ziffert, Annette G. Beck-Sickinger

    Abstract Functionally selective ligands to address specific cellular responses downstream of G protein-coupled receptors (GPCR) open up new possibilities for therapeutics. We designed and characterized novel subtype- and pathway-selective ligands. Substitution of position Q34 of neuropeptide Y to glycine (G34-NPY) results in unprecedented selectivity over all other YR subtypes. Moreover, this ligand displays a significant bias towards activation of the Gi/o pathway over recruitment of arrestin-3. Notably, no bias is observed for an established Y1R versus Y2R selective ligand carrying a proline at position 34 (F7,P34-NPY). Next, we investigated the spatio-temporal signaling at the Y1R and demonstrated that G protein-biased ligands promote a prolonged localization at the cell membrane, which leads to enhanced G protein signaling, while endosomal receptors do not contribute to cAMP signaling. Thus, spatial components are critical for the signaling of the Y1R that can be modulated by tailored ligands and represent a novel mode for biased pathways. Graphic abstract

  • Human pluripotent stem cell-derived chondroprogenitors for cartilage tissue engineering
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-08
    Naoki Nakayama, Azim Pothiawala, John Y. Lee, Nadine Matthias, Katsutsugu Umeda, Bryan K. Ang, Johnny Huard, Yun Huang, Deqiang Sun

    Abstract The cartilage of joints, such as meniscus and articular cartilage, is normally long lasting (i.e., permanent). However, once damaged, especially in large animals and humans, joint cartilage is not spontaneously repaired. Compensating the lack of repair activity by supplying cartilage-(re)forming cells, such as chondrocytes or mesenchymal stromal cells, or by transplanting a piece of normal cartilage, has been the basis of therapy for biological restoration of damaged joint cartilage. Unfortunately, current biological therapies face problems on a number of fronts. The joint cartilage is generated de novo from a specialized cell type, termed a ‘joint progenitor’ or ‘interzone cell’ during embryogenesis. Therefore, embryonic chondroprogenitors that mimic the property of joint progenitors might be the best type of cell for regenerating joint cartilage in the adult. Pluripotent stem cells (PSCs) are expected to differentiate in culture into any somatic cell type through processes that mimic embryogenesis, making human (h)PSCs a promising source of embryonic chondroprogenitors. The major research goals toward the clinical application of PSCs in joint cartilage regeneration are to (1) efficiently generate lineage-specific chondroprogenitors from hPSCs, (2) expand the chondroprogenitors to the number needed for therapy without loss of their chondrogenic activity, and (3) direct the in vivo or in vitro differentiation of the chondroprogenitors to articular or meniscal (i.e., permanent) chondrocytes rather than growth plate (i.e., transient) chondrocytes. This review is aimed at providing the current state of research toward meeting these goals. We also include our recent achievement of successful generation of “permanent-like” cartilage from long-term expandable, hPSC-derived ectomesenchymal chondroprogenitors.

  • Metabolic regulation of neurodifferentiation in the adult brain
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-07
    Camilla Maffezzini, Javier Calvo-Garrido, Anna Wredenberg, Christoph Freyer

    Understanding the mechanisms behind neurodifferentiation in adults will be an important milestone in our quest to identify treatment strategies for cognitive disorders observed during our natural ageing or disease. It is now clear that the maturation of neural stem cells to neurones, fully integrated into neuronal circuits requires a complete remodelling of cellular metabolism, including switching the cellular energy source. Mitochondria are central for this transition and are increasingly seen as the regulatory hub in defining neural stem cell fate and neurodevelopment. This review explores our current knowledge of metabolism during adult neurodifferentiation.

  • Dynein-mediated nuclear translocation of yes-associated protein through microtubule acetylation controls fibroblast activation
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-07
    Eunae You, Panseon Ko, Jangho Jeong, Seula Keum, Jung-Woong Kim, Young-Jin Seo, Woo Keun Song, Sangmyung Rhee

    Abstract Myofibroblasts are the major cell type that is responsible for increase in the mechanical stiffness in fibrotic tissues. It has well documented that the TGF-β/Smad axis is required for myofibroblast differentiation under the rigid substrate condition. However, the mechanism driving myofibroblast differentiation in soft substrates remains unknown. In this research, we demonstrated that interaction of yes-associated protein (YAP) and acetylated microtubule via dynein, a microtubule motor protein drives nuclear localization of YAP in the soft matrix, which in turn increased TGF-β1-induced transcriptional activity of Smad for myofibroblast differentiation. Pharmacological and genetical disruption of dynein impaired the nuclear translocation of YAP and decreased the TGF-β1-induced Smad activity even though phosphorylation and nuclear localization of Smad occurred normally in α-tubulin acetyltransferase 1 (α-TAT1) knockout cell. Moreover, microtubule acetylation prominently appeared in the fibroblast-like cells nearby the blood vessel in the fibrotic liver induced by CCl4 administration, which was conversely decreased by TGF-β receptor inhibitor. As a result, quantitative inhibition of microtubule acetylation may be suggested as a new target for overcoming fibrotic diseases.

  • An intact keratin network is crucial for mechanical integrity and barrier function in keratinocyte cell sheets
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-07
    Susanne Karsch, Fanny Büchau, Thomas M. Magin, Andreas Janshoff

    The isotype-specific composition of the keratin cytoskeleton is important for strong adhesion, force resilience, and barrier function of the epidermis. However, the mechanisms by which keratins regulate these functions are still incompletely understood. In this study, the role and significance of the keratin network for mechanical integrity, force transmission, and barrier formation were analyzed in murine keratinocytes. Following the time-course of single-cell wound closure, wild-type (WT) cells slowly closed the gap in a collective fashion involving tightly connected neighboring cells. In contrast, the mechanical response of neighboring cells was compromised in keratin-deficient cells, causing an increased wound area initially and an inefficient overall wound closure. Furthermore, the loss of the keratin network led to impaired, fragmented cell–cell junctions, and triggered a profound change in the overall cellular actomyosin architecture. Electric cell-substrate impedance sensing of cell junctions revealed a dysfunctional barrier in knockout (Kty−/−) cells compared to WT cells. These findings demonstrate that Kty−/− cells display a novel phenotype characterized by loss of mechanocoupling and failure to form a functional barrier. Re-expression of K5/K14 rescued the barrier defect to a significant extent and reestablished the mechanocoupling with remaining discrepancies likely due to the low abundance of keratins in that setting. Our study reveals the major role of the keratin network for mechanical homeostasis and barrier functionality in keratinocyte layers.

  • Hypoxia: a barricade to conquer the pancreatic cancer
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-06
    Zhen Tan, Jin Xu, Bo Zhang, Si Shi, Xianjun Yu, Chen Liang

    Pancreatic cancer (PC) remains one of the most extremely lethal malignancies worldwide due to late diagnosis and early metastasis, with a 1-year overall survival rate of approximately 20%. The hypoxic microenvironment, induced by intratumoral hypoxia, promotes tumor invasion and progression, leading to chemotherapy or radiotherapy resistance and eventual mortality after treatment of PC. However, the role of the hypoxic microenvironment in PC is complicated and requires further investigation. In this article, we review recent advances regarding the regulation of malignant behaviors in PC, which provide insight into the potential of hypoxic microenvironment activation therapy for the therapeutic agents.

  • The role of lipocalin-2 in age-related macular degeneration (AMD)
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-04
    Sayan Ghosh, Nadezda Stepicheva, Meysam Yazdankhah, Peng Shang, Alan M. Watson, Stacey Hose, Haitao Liu, Joseph Weiss, J. Samuel Zigler, Mallika Valapala, Simon C. Watkins, Debasish Sinha

    Abstract Lipocalins are a family of secreted adipokines which play important roles in various biological processes. Lipocalin-2 (LCN-2) has been shown to be involved in acute and chronic inflammation. This particular protein is critical in the pathogenesis of several diseases including cancer, diabetes, obesity, and multiple sclerosis. Herein, we discuss the general molecular basis for the involvement of LCN-2 in acute infections and chronic disease progression and also ascertain the probable role of LCN-2 in ocular diseases, particularly in age-related macular degeneration (AMD). We elaborate on the signaling cascades which trigger LCN-2 upregulation in AMD and suggest therapeutic strategies for targeting such pathways.

  • Curse of the devil: molecular insights into the emergence of transmissible cancers in the Tasmanian devil ( Sarcophilus harrisii )
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-03
    Amanda L. Patchett, Andrew S. Flies, A. Bruce Lyons, Gregory M. Woods

    Abstract The Tasmanian devil (Sarcophilus harrisii) is the only mammalian species known to be affected by multiple transmissible cancers. Devil facial tumours 1 and 2 (DFT1 and DFT2) are independent neoplastic cell lineages that produce large, disfiguring cancers known as devil facial tumour disease (DFTD). The long-term persistence of wild Tasmanian devils is threatened due to the ability of DFTD cells to propagate as contagious allografts and the high mortality rate of DFTD. Recent studies have demonstrated that both DFT1 and DFT2 cancers originated from founder cells of the Schwann cell lineage, an uncommon origin of malignant cancer in humans. This unprecedented finding has revealed a potential predisposition of Tasmanian devils to transmissible cancers of the Schwann cell lineage. In this review, we compare the molecular nature of human Schwann cells and nerve sheath tumours with DFT1 and DFT2 to gain insights into the emergence of transmissible cancers in the Tasmanian devil. We discuss a potential mechanism, whereby Schwann cell plasticity and frequent wounding in Tasmanian devils combine with an inherent cancer predisposition and low genetic diversity to give rise to transmissible Schwann cell cancers in devils on rare occasions.

  • GPR50-Ctail cleavage and nuclear translocation: a new signal transduction mode for G protein-coupled receptors
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-03
    Raise Ahmad, Olivier Lahuna, Anissa Sidibe, Avais Daulat, Qiang Zhang, Marine Luka, Jean-Luc Guillaume, Sarah Gallet, François Guillonneau, Juliette Hamroune, Sophie Polo, Vincent Prévot, Philippe Delagrange, Julie Dam, Ralf Jockers

    Abstract Transmission of extracellular signals by G protein-coupled receptors typically relies on a cascade of intracellular events initiated by the activation of heterotrimeric G proteins or β-arrestins followed by effector activation/inhibition. Here, we report an alternative signal transduction mode used by the orphan GPR50 that relies on the nuclear translocation of its carboxyl-terminal domain (CTD). Activation of the calcium-dependent calpain protease cleaves off the CTD from the transmembrane-bound GPR50 core domain between Phe-408 and Ser-409 as determined by MALDI-TOF-mass spectrometry. The cytosolic CTD then translocates into the nucleus assisted by its ‘DPD’ motif, where it interacts with the general transcription factor TFII-I to regulate c-fos gene transcription. RNA-Seq analysis indicates a broad role of the CTD in modulating gene transcription with ~ 8000 differentially expressed genes. Our study describes a non-canonical, direct signaling mode of GPCRs to the nucleus with similarities to other receptor families such as the NOTCH receptor

  • Frizzled 1 and Wnt1 as new potential therapeutic targets in the traumatically injured spinal cord
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-03
    Pau González, Carlos González-Fernández, Yolanda Campos-Martín, Manuela Mollejo, Melissa Carballosa-Gautam, Alexander Marcillo, Michael Norenberg, Francisco Javier Rodríguez

    Abstract Despite the experimental evidence pointing to a significant role of the Wnt family of proteins in physiological and pathological rodent spinal cord functioning, its potential relevance in the healthy and traumatically injured human spinal cord as well as its therapeutic potential in spinal cord injury (SCI) are still poorly understood. To get further insight into these interesting issues, we first demonstrated by quantitative Real-Time PCR and simple immunohistochemistry that detectable mRNA expression of most Wnt components, as well as protein expression of all known Wnt receptors, can be found in the healthy human spinal cord, supporting its potential involvement in human spinal cord physiology. Moreover, evaluation of Frizzled (Fz) 1 expression by double immunohistochemistry showed that its spatio-temporal and cellular expression pattern in the traumatically injured human spinal cord is equivalent to that observed in a clinically relevant model of rat SCI and suggests its potential involvement in SCI progression/outcome. Accordingly, we found that long-term lentiviral-mediated overexpression of the Fz1 ligand Wnt1 after rat SCI improves motor functional recovery, increases myelin preservation and neuronal survival, and reduces early astroglial reactivity and NG2+ cell accumulation, highlighting the therapeutic potential of Wnt1 in this neuropathological situation.

  • Epigenetics in age-related macular degeneration: new discoveries and future perspectives
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-02
    M. Gemenetzi, A. J. Lotery

    Abstract The study of epigenetics has explained some of the ‘missing heritability’ of age-related macular degeneration (AMD). The epigenome also provides a substantial contribution to the organisation of the functional retina. There is emerging evidence of specific epigenetic mechanisms associated with AMD. This ‘AMD epigenome’ may offer the chance to develop novel AMD treatments.

  • Senescence in the pathogenesis of age-related macular degeneration
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-02
    Janusz Blasiak

    Age-related macular degeneration (AMD) is a complex eye disease underlined by the death of photoreceptors and degeneration of retinal pigment epithelium (RPE) and choriocapillaris (CC). The mechanism(s) responsible for massive and progressive retinal degeneration is not completely known. Senescence, a state of permanent inhibition of cell growth, may be induced by many factors important for AMD pathogenesis and results in senescence-associated secretory phenotype (SASP) that releases growth factors, cytokines, chemokines, proteases and other molecules inducing inflammation and other AMD-related effects. These effects can be induced in the affected cell and neighboring cells, leading to progression of AMD phenotype. Senescent cells also release reactive oxygen species that increase SASP propagation. Many other pathways of senescence-related AMD pathogenesis, including autophagy, the cGAS–STING signaling, degeneration of CC by membrane attack complex, can be considered. A2E, a fluorophore present in lipofuscin, amyloid-beta peptide and humanin, a mitochondria-derived peptide, may link AMD with senescence. Further studies on senescence in AMD pathogenesis to check the possibility of opening a perspective of the use of drugs killing senescent cells (senolytics) and terminating SASP bystander effects (senostatics) might be beneficial for AMD that at present is an incurable disease.

  • Introduction to the multi-author review on macular degeneration
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-02
    Anu Kauppinen

    Abstract Prolonged life expectancies contribute to the increasing prevalence of age-related macular degeneration (AMD) that is already the leading cause of severe vision loss among the elderly in developed countries. In dry AMD, the disease culminates into vast retinal atrophy, whereas the wet form is characterized by retinal edema and sudden vision loss due to neovascularization originating from the choroid beneath the Bruch’s membrane. There is no treatment for dry AMD and despite intravitreal injections of anti-vascular endothelial growth factor (VEGF) that suppress the neovessel formation, also wet AMD needs new therapies to prevent the disease progression and to serve patients lacking of positive response to current medicines. Knowledge on disease mechanisms is a prerequisite for the drug development, which is hindered by the multifactorial nature of AMD. Numerous distinguished publications have revealed AMD mechanisms at the cellular and molecular level and in this multi-author review, we take a bit broader look at the topic with some novel aspects.

  • The role of lymphocytes and phagocytes in age-related macular degeneration (AMD)
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-02
    Verena Behnke, Anne Wolf, Thomas Langmann

    Abstract Age-related macular degeneration (AMD) is a leading cause of visual impairment of the elderly population. Since AMD is a multifactorial age-related disease with various genetic risk factors, the understanding of its complex pathophysiology is still limited. However, animal experiments, genome-wide association data and the molecular profiling of AMD patient samples have highlighted a key role of systemic and local immune processes that contribute to this chronic eye disease. In this overview article, we concentrate on the role of lymphocytes and mononuclear phagocytes and their interplay in triggering a persistent immune response in the AMD retina. We preferentially review findings from human immune cell analyses and complement these with related findings in experimental models. We conclude that both immune cell types as their signaling network may be a rich source to identify novel molecular targets for immunomodulation in AMD.

  • Highly photostable fluorescent labeling of proteins in live cells using exchangeable coiled coils heterodimerization
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-02
    Maxim M. Perfilov, Nadya G. Gurskaya, Ekaterina O. Serebrovskaya, Pavel A. Melnikov, Sergey L. Kharitonov, Tylor R. Lewis, Vadim Y. Arshavsky, Vladimir P. Baklaushev, Alexander S. Mishin, Konstantin A. Lukyanov

    Fluorescent proteins are commonly used to label target proteins in live cells. However, the conventional approach based on covalent fusion of targeted proteins with fluorescent protein probes is limited by the slow rate of fluorophore maturation and irretrievable loss of fluorescence due to photobleaching. Here, we report a genetically encoded protein labeling system utilizing transient interactions of small, 21–28 residues-long helical protein tags (K/E coils, KEC). In this system, a protein of interest, covalently tagged with a single coil, is visualized through binding to a cytoplasmic fluorescent protein carrying a complementary coil. The reversible heterodimerization of KECs, whose affinity can be tuned in a broad concentration range from nanomolar to micromolar, allows continuous exchange and replenishment of the tag bound to a targeted protein with the entire cytosolic pool of soluble fluorescent coils. We found that, under conditions of partial illumination of living cells, the photostability of labeling with KECs exceeds that of covalently fused fluorescent probes by approximately one order of magnitude. Similarly, single-molecule localization microscopy with KECs provided higher labeling density and allowed a much longer duration of imaging than with conventional fusion to fluorescent proteins. We also demonstrated that this method is well suited for imaging newly synthesized proteins, because the labeling efficiency by KECs is not dependent on the rate of fluorescent protein maturation. In conclusion, KECs can be used to visualize various target proteins which are directly exposed to the cytosol, thereby enabling their advanced characterization in time and space.

  • The dark side of Alzheimer’s disease: unstructured biology of proteins from the amyloid cascade signaling pathway
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-02
    Kundlik Gadhave, Bhuvaneshwari R. Gehi, Prateek Kumar, Bin Xue, Vladimir N. Uversky, Rajanish Giri

    Alzheimer’s disease (AD) is a leading cause of age-related dementia worldwide. Despite more than a century of intensive research, we are not anywhere near the discovery of a cure for this disease or a way to prevent its progression. Among the various molecular mechanisms proposed for the description of the pathogenesis and progression of AD, the amyloid cascade hypothesis, according to which accumulation of a product of amyloid precursor protein (APP) cleavage, amyloid β (Aβ) peptide, induces pathological changes in the brain observed in AD, occupies a unique niche. Although multiple proteins have been implicated in this amyloid cascade signaling pathway, their structure–function relationships are mostly unexplored. However, it is known that two major proteins related to AD pathology, Aβ peptide, and microtubule-associated protein tau belong to the category of intrinsically disordered proteins (IDPs), which are the functionally important proteins characterized by a lack of fixed, ordered three-dimensional structure. IDPs and intrinsically disordered protein regions (IDPRs) play numerous vital roles in various cellular processes, such as signaling, cell cycle regulation, macromolecular recognition, and promiscuous binding. However, the deregulation and misfolding of IDPs may lead to disturbed signaling, interactions, and disease pathogenesis. Often, molecular recognition-related IDPs/IDPRs undergo disorder-to-order transition upon binding to their biological partners and contain specific disorder-based binding motifs, known as molecular recognition features (MoRFs). Knowing the intrinsic disorder status and disorder-based functionality of proteins associated with amyloid cascade signaling pathway may help to untangle the mechanisms of AD pathogenesis and help identify therapeutic targets. In this paper, we have used multiple computational tools to evaluate the presence of intrinsic disorder and MoRFs in 27 proteins potentially relevant to the amyloid cascade signaling pathway. Among these, BIN1, APP, APOE, PICALM, PSEN1 and CD33 were found to be highly disordered. Furthermore, their disorder-based binding regions and associated short linear motifs have also been identified. These findings represent important foundation for the future research, and experimental characterization of disordered regions in these proteins is required to better understand their roles in AD pathogenesis.

  • hnRNPA2B1 inhibits the exosomal export of miR-503 in endothelial cells
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-02
    Jennifer Pérez-Boza, Amandine Boeckx, Michele Lion, Franck Dequiedt, Ingrid Struman

    Abstract The chemotherapeutic drug epirubicin increases the exosomal export of miR-503 in endothelial cells. To understand the mechanisms behind this process, we transfected endothelial cells with miR-503 carrying a biotin tag. Then, we pulled-down the proteins interacting with miR-503 and studied their role in microRNA exosomal export. A total of four different binding partners were identified by mass spectrometry and validated by western blotting and negative controls, among them ANXA2 and hnRNPA2B1. Using knock-down systems combined with pull-down analysis, we determined that epirubicin mediates the export of miR-503 by disrupting the interaction between hnRNPA2B1 and miR-503. Then, both ANXA2 and miR-503 are sorted into exosomes while hnRNPA2B1 is relocated into the nucleus. The combination of these processes culminates in the increased export of miR-503. These results suggest, for the first time, that RNA-binding proteins can negatively regulate the exosomal sorting of microRNAs.

  • Pharmacological inhibition of androgen receptor expression induces cell death in prostate cancer cells
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-01
    In-Sung Song, Yu Jeong Jeong, Jueun Kim, Kyoung-Hwa Seo, Nam-In Baek, Yunlim Kim, Choung-Soo Kim, Sung-Wuk Jang

    The androgen receptor (AR) plays an important role in the pathogenesis and development of prostate cancer (PCa). Mostly, PCa progresses to androgen-independent PCa, which has activated AR signaling from androgen-dependent PCa. Thus, inhibition of AR signaling may be an important therapeutic target in androgen-dependent and castration-resistant PCa. In this study, we determined the anticancer effect of a newly found natural compound, sakurasosaponin (S-saponin), using androgen-dependent and castration-resistant PCa cell lines. S-saponin induces mitochondrial-mediated cell death in both androgen-dependent (LNCaP) and castration-resistant (22Rv1 and C4-2) PCa cells, via AR expression. S-saponin treatment induces a decrease in AR expression in a time- and dose-dependent manner and a potent decrease in the expression of its target genes, including prostate-specific antigen (PSA), transmembrane protease, serin 2 (TMPRSS2), and NK3 homeobox 1 (NKX3.1). Furthermore, S-saponin treatment decreases B-cell lymphoma-extra large (Bcl-xL) and mitochondrial membrane potential, thereby increasing the release of cytochrome c into the cytosol. Moreover, Bcl-xL inhibition and subsequent mitochondria-mediated cell death caused by S-saponin were reversed by Bcl-xL or AR overexpression. Interestingly, S-saponin-mediated cell death was significantly reduced by a reactive oxygen species (ROS) scavenger, N-acetylcystein. Animal xenograft experiments showed that S-saponin treatment significantly reduced tumor growth of AR-positive 22Rv1 xenografts but not AR-negative PC-3 xenografts. Taken together, for the first time, our results revealed that S-saponin induces mitochondrial-mediated cell death in androgen-dependent and castration-resistant cells through regulation of AR mechanisms, including downregulation of Bcl-xL expression and induction of ROS stress by decreasing mitochondrial membrane potential.

  • The versatile Kv channels in the nervous system: actions beyond action potentials
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-01
    Louis W. C. Chow, Yuk- Man Leung

    Voltage-gated K+ (Kv) channel opening repolarizes excitable cells by allowing K+ efflux. Over the last two decades, multiple Kv functions in the nervous system have been found to be unrelated to or beyond the immediate control of excitability, such as shaping action potential contours or regulation of inter-spike frequency. These functions include neuronal exocytosis and neurite formation, neuronal cell death, regulation of astrocyte Ca2+, glial cell and glioma proliferation. Some of these functions have been shown to be independent of K+ conduction, that is, they suggest the non-canonical functions of Kv channels. In this review, we focus on neuronal or glial plasmalemmal Kv channel functions which are unrelated to shaping action potentials or immediate control of excitability. Similar functions in other cell types will be discussed to some extent in appropriate contexts.

  • Communication between human macrophages and epithelial cancer cell lines dictates lipid mediator biosynthesis
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-01
    Markus Werner, Simona Pace, Anna Czapka, Paul M. Jordan, Jana Gerstmeier, Andreas Koeberle, Oliver Werz

    In tumors, cancer cells coexist and communicate with macrophages that can promote tumorigenesis via pro-inflammatory signals. Lipid mediators (LMs), produced mainly by cyclooxygenases (COXs) or lipoxygenases (LOs), display a variety of biological functions with advantageous or deleterious consequences for tumors. Here, we investigated how the communication between human monocyte-derived M2-like macrophages (MDM) and cancer cells affects LM biosynthesis using LM metabololipidomics. Coculture of human MDM with human A549 epithelial lung carcinoma cells, separated by a semipermeable membrane, increased LM formation by MDM upon subsequent activation. Strongest effects were observed on 5-LO-derived LM. While expression of the 5-LO pathway was not altered, p38 MAPK and the downstream MAPKAPK-2 that phosphorylates and stimulates 5-LO were more susceptible for activation in MDM upon precedent coculture with A549 cells as compared to monocultures. Accordingly, the p38 MAPK inhibitor Skepinone-L selectively prevented this increase in 5-LO product formation. Also, 5-LO-/15-LO-derived LM including lipoxin A4, resolvin D2 and D5 were elevated after coculture with A549 cells, correlating to increased 15-LO-1 protein levels. In contrast to cancer cells, coincubation with non-transformed human umbilical vein endothelial cells (HUVEC) did not affect LM production in MDM. Vice versa, MDM increased COX-2 protein expression and COX-mediated prostanoid formation in cancer cells. Conclusively, our data reveal that the communication between MDM and cancer cells can strikingly modulate the biosynthetic capacities to produce bioactive LM with potential relevance for tumor biology.

  • Eph receptors: the bridge linking host and virus
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-31
    Jia Wang, Xiang Zheng, Qiu Peng, Xuemei Zhang, Zailong Qin

    Eph (erythropoietin-producing hepatoma) receptors and Ephrin ligands constitute the largest subfamily of receptor tyrosine kinase (RTK), which were first discovered in tumors. Heretofore, Eph protein has been shown to be involved in various tumor biological behaviors including proliferation and progression. The occurrence of specific types of tumor is closely related to the virus infection. Virus entry is a complex process characterized by a series of events. The entry into target cells is an essential step for virus to cause diseases, which requires the fusion of the viral envelope and host cellular membrane mediated by viral glycoproteins and cellular receptors. Integrin molecules are well known as entry receptors for most herpes viruses. However, in recent years, Eph receptors and their Ephrin ligands have been reported to be involved in virus infections. The main mechanism may be the interaction between Eph receptors and conserved viral surface glycoprotein, such as the gH/gL or gB protein of the herpesviridae. This review focuses on the relationship between Eph receptor family and virus infection that summarize the processes of viruses such as EBV, KSHV, HCV, RRV, etc., infecting target cells through Eph receptors and activating its downstream signaling pathways resulting in malignancies. Finally, we discussed the perspectives to block virus infection, prevention, and treatment of viral-related tumors via Eph receptor family.

  • Integrative genomics reveal a role for MCPIP1 in adipogenesis and adipocyte metabolism
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-31
    Magdalena Losko, Dobrochna Dolicka, Natalia Pydyn, Urszula Jankowska, Sylwia Kedracka-Krok, Maria Kulecka, Agnieszka Paziewska, Michal Mikula, Piotr Major, Marek Winiarski, Andrzej Budzynski, Jolanta Jura

    Abstract Obesity is considered a serious chronic disease, associated with an increased risk of developing cardiovascular diseases, non-alcoholic fatty liver disease and type 2 diabetes. Monocyte chemoattractant protein-1-induced protein-1 (MCPIP1) is an RNase decreasing stability of transcripts coding for inflammation-related proteins. In addition, MCPIP1 plays an important role in the regulation of adipogenesis in vitro by reducing the expression of key transcription factors, including C/EBPβ. To elucidate the role of MCPIP1 in adipocyte biology, we performed RNA-Seq and proteome analysis in 3T3-L1 adipocytes overexpressing wild-type (WTMCPIP1) and the mutant form of MCPIP1 protein (D141NMCPIP1). Our RNA-Seq analysis followed by confirmatory Q-RT-PCR revealed that elevated MCPIP1 levels in 3T3-L1 adipocytes upregulated transcripts encoding proteins involved in signal transmission and cellular remodeling and downregulated transcripts of factors involved in metabolism. These data are consistent with our proteomic analysis, which showed that MCPIP1 expressing adipocytes exhibit upregulation of proteins involved in cellular organization and movement and decreased levels of proteins involved in lipid and carbohydrate metabolism. Moreover, MCPIP1 adipocytes are characterized by decreased level of insulin receptor, reduced insulin-induced Akt phosphorylation, as well as depleted Glut4 level and impaired glucose uptake. Overexpression of Glut4 in 3T3-L1 cells expressed WTMCPIP1 rescued adipogenesis. Interestingly, we found decreased level of MCPIP1 along with an increase in body mass index in subcutaneous adipose tissue. The presented data show a novel role of MCPIP1 in modulating insulin sensitivity in adipocytes. Overall, our findings demonstrate that MCPIP1 is an important regulator of adipogenesis and adipocyte metabolism.

  • The role of hypoxia-inducible factors in neovascular age-related macular degeneration: a gene therapy perspective
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-31
    Parviz Mammadzada, Pablo M. Corredoira, Helder André

    Understanding the mechanisms that underlie age-related macular degeneration (AMD) has led to the identification of key molecules. Hypoxia-inducible transcription factors (HIFs) have been associated with choroidal neovascularization and the progression of AMD into the neovascular clinical phenotype (nAMD). HIFs regulate the expression of multiple growth factors and cytokines involved in angiogenesis and inflammation, hallmarks of nAMD. This knowledge has propelled the development of a new group of therapeutic strategies focused on gene therapy. The present review provides an update on current gene therapies in ocular angiogenesis, particularly nAMD, from both basic and clinical perspectives.

  • Molecular crosstalk between cancer and neurodegenerative diseases
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-28
    Jiyeon Seo, Mikyoung Park

    Abstract The progression of cancers and neurodegenerative disorders is largely defined by a set of molecular determinants that are either complementarily deregulated, or share remarkably overlapping functional pathways. A large number of such molecules have been demonstrated to be involved in the progression of both diseases. In this review, we particularly discuss our current knowledge on p53, cyclin D, cyclin E, cyclin F, Pin1 and protein phosphatase 2A, and their implications in the shared or distinct pathways that lead to cancers or neurodegenerative diseases. In addition, we focus on the inter-dependent regulation of brain cancers and neurodegeneration, mediated by intercellular communication between tumor and neuronal cells in the brain through the extracellular microenvironment. Finally, we shed light on the therapeutic perspectives for the treatment of both cancer and neurodegenerative disorders.

  • Behind the pathology of macrophage-associated demyelination in inflammatory neuropathies: demyelinating Schwann cells
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-28
    Hwan Tae Park, Young Hee Kim, Kyung Eun Lee, Jong Kuk Kim

    In inflammatory peripheral demyelinating disorders, demyelination represents segmental demyelination in which the myelin sheath of a myelinating Schwann cell (SC) is completely removed by macrophages or a partial myelin degeneration in the paranode occurring due to autoantibodies attacking the node/paranode. For the segmental demyelination from living myelin-forming SCs, macrophages infiltrate within the endoneurium and insinuate between myelin lamellae and the cytoplasm of SCs, and the myelin is then removed via phagocytosis. During the macrophage invasion into the SC cytoplasm from the node of Ranvier and internodal areas, the attacked SCs do not remain quiescent but transdifferentiate into inflammatory demyelinating SCs (iDSCs), which exhibit unique demyelination pathologies, such as myelin uncompaction from Schmidt-Lanterman incisures with myelin lamellae degeneration. The longitudinal extension of this self-myelin clearance process of iDSCs into the nodal region is associated with the degeneration of nodal microvilli and paranodal loops, which provides a potential locus for macrophage infiltration. In addition to the nodal intrusion, macrophages appear to be able to invade fenestrated internodal plasma membrane or the degenerated outer mesaxon of iDSC. These SC demyelination morphologies indicate that the SC reprogramming to iDSCs may be a prerequisite for macrophage-mediated inflammatory demyelination. In contrast, paranodal demyelination caused by autoantibodies to nodal/paranodal antigens does not result in iDSC-dependent macrophage infiltration and subsequent segmental demyelination. In the context of inflammatory demyelination, the novel perspective of iDSCs provides an important viewpoint to understand the pathophysiology of demyelinating peripheral neuropathies and establish diagnostic and therapeutic strategies.

  • Extracellular signal-regulated kinase 1/2 regulates NAD metabolism during acute kidney injury through microRNA-34a-mediated NAMPT expression
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-23
    Justin B. Collier, Rick G. Schnellmann

    Abstract Prior studies have established the important role of extracellular signal-regulated kinase 1/2 (ERK1/2) as a mediator of acute kidney injury (AKI). We demonstrated rapid ERK1/2 activation induced renal dysfunction following ischemia/reperfusion (IR)-induced AKI and downregulated the mitochondrial biogenesis (MB) regulator, peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) in mice. In this study, ERK1/2 regulation of cellular nicotinamide adenine dinucleotide (NAD) and PGC-1α were explored. Inhibition of ERK1/2 activation during AKI in mice using the MEK1/2 inhibitor, trametinib, attenuated renal cortical oxidized NAD (NAD+) depletion. The rate-limiting NAD biosynthesis salvage enzyme, NAMPT, decreased following AKI, and this decrease was prevented by ERK1/2 inhibition. The microRNA miR34a decreased with the inhibition of ERK1/2, leading to increased NAMPT protein. Mice treated with a miR34a mimic prevented increases in NAMPT protein in the renal cortex in the presence of ERK1/2 inhibition. In addition, ERK1/2 activation increased acetylated PGC-1α, the less active form, whereas inhibition of ERK1/2 activation prevented an increase in acetylated PGC-1α after AKI through SIRT1 and NAD+ attenuation. These results implicate IR-induced ERK1/2 activation as an important contributor to the downregulation of both PGC-1α and NAD+ pathways that ultimately decrease cellular metabolism and renal function. Inhibition of ERK1/2 activation prior to the initiation of IR injury attenuated decreases in PGC-1α and NAD+ and prevented kidney dysfunction.

  • Cas12a mediates efficient and precise endogenous gene tagging via MITI: microhomology-dependent targeted integrations
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-17
    Pan Li, Lijun Zhang, Zhifang Li, Chunlong Xu, Xuguang Du, Sen Wu

    Efficient exogenous DNA integration can be mediated by Cas9 through the non-homology end-joining pathway. However, such integrations are often imprecise and contain a variety of mutations at the junctions between the external DNA and the genomic loci. Here we describe a microhomology-dependent targeted integration method, designated MITI, for precise site-specific gene insertions. We found that the MITI strategy yielded higher knock-in accuracy than Cas9 HITI for the insertion of external DNA and tagging endogenous genes. Furthermore, in combination with negative selection and four different CrRNAs targeting donor vectors and genome-targeted sites with a CrRNA array, MITI facilitated precise ligation at all junctions. Therefore, our Cas12a-based MITI method increases the repertoire of precision genome engineering approaches and provides a useful tool for various gene editing applications.

  • Modulation of SRSF2 expression reverses the exhaustion of TILs via the epigenetic regulation of immune checkpoint molecules
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-14
    Ziqiang Wang, Kun Li, Wei Chen, Xiaoxia Wang, Yikun Huang, Weiming Wang, Wanjun Wu, Zhiming Cai, Weiren Huang

    The elevated expression of immune checkpoints by the tumor microenvironment is associated with poor prognosis in several cancers due to the exhaustion of tumor-infiltrating lymphocytes (TILs), and the effective suppression of the expression of these genes is key to reversing the exhaustion of TILs. Herein, we determined that serine/arginine-rich splicing factor 2 (SRSF2) is a target for blocking the tumor microenvironment-associated immunosuppressive effects. We found that the expression of SRSF2 was increased in exhausted T cells and that SRSF2 was involved in multiple immune checkpoint molecules mediating TILs’ exhaustion. Furthermore, SRSF2 was revealed to regulate the transcription of these immune checkpoint genes by associating with an acyl-transferases P300/CBP complex and altering the H3K27Ac level near these genes, thereafter influencing the recruitment of signal transducer and activator of transcription 3 (STAT3) to these gene promoters. Collectively, our data indicated that SRSF2 functions as a modulator of the anti-tumor response of T cells and may be a therapeutic target for reversing the exhaustion of TILs.

  • Astrocyte-specific NDRG2 gene: functions in the brain and neurological diseases
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-13
    Xin Li, Xiuquan Wu, Peng Luo, Lize Xiong

    In recent years, the roles of astrocytes of the central nervous system in brain function and neurological disease have drawn increasing attention. As a member of the N-myc downstream-regulated gene (NDRG) family, NDRG2 is principally expressed in astrocytes of the central nervous system. NDRG2, which is involved in cell proliferation and differentiation, is commonly regarded as a tumor suppressor. In astrocytes, NDRG2 affects the regulation of apoptosis, astrogliosis, blood–brain barrier integrity, and glutamate clearance. Several preclinical studies have revealed that NDRG2 is implicated in the pathogenesis of many neurological diseases not limited to tumors (mostly glioma in the nervous system), such as stroke, neurodegeneration (Alzheimer’s disease and Parkinson’s disease), and psychiatric disorders (depression and attention deficit hyperactivity disorder). This review summarizes the biological functions of NDRG2 under physiological and pathological conditions, and further discusses the roles of NDRG2 during the occurrence and development of neurological diseases.

  • TGFβ-induced metabolic reprogramming during epithelial-to-mesenchymal transition in cancer
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-10
    Wan Hua, Peter ten Dijke, Sarantos Kostidis, Martin Giera, Marten Hornsveld

    Metastasis is the most frequent cause of death in cancer patients. Epithelial-to-mesenchymal transition (EMT) is the process in which cells lose epithelial integrity and become motile, a critical step for cancer cell invasion, drug resistance and immune evasion. The transforming growth factor-β (TGFβ) signaling pathway is a major driver of EMT. Increasing evidence demonstrates that metabolic reprogramming is a hallmark of cancer and extensive metabolic changes are observed during EMT. The aim of this review is to summarize and interconnect recent findings that illustrate how changes in glycolysis, mitochondrial, lipid and choline metabolism coincide and functionally contribute to TGFβ-induced EMT. We describe TGFβ signaling is involved in stimulating both glycolysis and mitochondrial respiration. Interestingly, the subsequent metabolic consequences for the redox state and lipid metabolism in cancer cells are found to be in favor of EMT as well. Combined we illustrate that a better understanding of the mechanistic links between TGFβ signaling, cancer metabolism and EMT holds promising strategies for cancer therapy, some of which are already actively being explored in the clinic.

  • Vsx1 and Chx10 paralogs sequentially secure V2 interneuron identity during spinal cord development
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-10
    Stéphanie Debrulle, Charlotte Baudouin, Maria Hidalgo-Figueroa, Barbara Pelosi, Cédric Francius, Vincent Rucchin, Kara Ronellenfitch, Robert L. Chow, Fadel Tissir, Soo-Kyung Lee, Frédéric Clotman

    Paralog factors are usually described as consolidating biological systems by displaying redundant functionality in the same cells. Here, we report that paralogs can also cooperate in distinct cell populations at successive stages of differentiation. In mouse embryonic spinal cord, motor neurons and V2 interneurons differentiate from adjacent progenitor domains that share identical developmental determinants. Therefore, additional strategies secure respective cell fate. In particular, Hb9 promotes motor neuron identity while inhibiting V2 differentiation, whereas Chx10 stimulates V2a differentiation while repressing motor neuron fate. However, Chx10 is not present at the onset of V2 differentiation and in other V2 populations. In the present study, we show that Vsx1, the single paralog of Chx10, which is produced earlier than Chx10 in V2 precursors, can inhibit motor neuron differentiation and promote V2 interneuron production. However, the single absence of Vsx1 does not impact on V2 fate consolidation, suggesting that lack of Vsx1 may be compensated by other factors. Nevertheless, Vsx1 cooperates with Chx10 to prevent motor neuron differentiation in early V2 precursors although these two paralog factors are not produced in the same cells. Hence, this study uncovers an original situation, namely labor division, wherein paralog genes cooperate at successive steps of neuronal development.

  • PIWI family proteins as prognostic markers in cancer: a systematic review and meta-analysis
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-09
    Alexios-Fotios A. Mentis, Efthimios Dardiotis, Nicholas A. Romas, Athanasios G. Papavassiliou

    P-element-induced-wimpy-testis-(PIWI)-like proteins are implicated in germ cells’ regulation and detected in numerous cancer types. In this meta-analysis, we aimed to associate, for the first time, the prognosis in cancer patients with intratumoral expression of PIWI family proteins.

  • HAS3-induced extracellular vesicles from melanoma cells stimulate IHH mediated c-Myc upregulation via the hedgehog signaling pathway in target cells
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-09
    Uma Thanigai Arasu, Ashik Jawahar Deen, Sanna Pasonen-Seppänen, Sami Heikkinen, Maciej Lalowski, Riikka Kärnä, Kai Härkönen, Petri Mäkinen, Elisa Lázaro-Ibáñez, Pia R-M Siljander, Sanna Oikari, Anna-Liisa Levonen, Kirsi Rilla

    Intercellular communication is fundamental to the survival and maintenance of all multicellular systems, whereas dysregulation of communication pathways can drive cancer progression. Extracellular vesicles (EVs) are mediators of cell-to-cell communication that regulate a variety of cellular processes involved in tumor progression. Overexpression of a specific plasma membrane enzyme, hyaluronan synthase 3 (HAS3), is one of the factors that can induce EV shedding. HAS3, and particularly its product hyaluronan (HA), are carried by EVs and are known to be associated with the tumorigenic properties of cancer cells. To elucidate the specific effects of cancerous, HAS3-induced EVs on target cells, normal human keratinocytes and melanoma cells were treated with EVs derived from GFP-HAS3 expressing metastatic melanoma cells. We found that the HA receptor CD44 participated in the regulation of EV binding to target cells. Furthermore, GFP-HAS3-positive EVs induced HA secretion, proliferation and invasion of target cells. Our results suggest that HAS3-EVs contains increased quantities of IHH, which activates the target cell hedgehog signaling cascade and leads to the activation of c-Myc and regulation of claspin expression. This signaling of IHH in HAS3-EVs resulted in increased cell proliferation. Claspin immunostaining correlated with HA content in human cutaneous melanocytic lesions, supporting our in vitro findings and suggesting a reciprocal regulation between claspin expression and HA synthesis. This study shows for the first time that EVs originating from HAS3 overexpressing cells carry mitogenic signals that induce proliferation and epithelial-to-mesenchymal transition in target cells. The study also identifies a novel feedback regulation between the hedgehog signaling pathway and HA metabolism in melanoma, mediated by EVs carrying HA and IHH.

  • Elucidation of protein interactions necessary for the maintenance of the BCR–ABL signaling complex
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-09
    Tomas Gregor, Michaela Kunova Bosakova, Alexandru Nita, Sara P. Abraham, Bohumil Fafilek, Nicole H. Cernohorsky, Jan Rynes, Silvie Foldynova-Trantirkova, Daniela Zackova, Jiri Mayer, Lukas Trantirek, Pavel Krejci

    Many patients with chronic myeloid leukemia in deep remission experience return of clinical disease after withdrawal of tyrosine kinase inhibitors (TKIs). This suggests signaling of inactive BCR–ABL, which allows the survival of cancer cells, and relapse. We show that TKI treatment inhibits catalytic activity of BCR–ABL, but does not dissolve BCR–ABL core signaling complex, consisting of CRKL, SHC1, GRB2, SOS1, cCBL, p85a-PI3K, STS1 and SHIP2. Peptide microarray and co-immunoprecipitation results demonstrate that CRKL binds to proline-rich regions located in C-terminal, intrinsically disordered region of BCR–ABL, that SHC1 requires pleckstrin homology, src homology and tyrosine kinase domains of BCR–ABL for binding, and that BCR–ABL sequence motif located in disordered region around phosphorylated tyrosine 177 mediates binding of three core complex members, i.e., GRB2, SOS1, and cCBL. Further, SHIP2 binds to the src homology and tyrosine kinase domains of BCR–ABL and its inositol phosphatase activity contributes to BCR–ABL-mediated phosphorylation of SHC1. Together, this study characterizes protein–protein interactions within the BCR–ABL core complex and determines the contribution of particular BCR–ABL domains to downstream signaling. Understanding the structure and dynamics of BCR–ABL interactome is critical for the development of drugs targeting integrity of the BCR–ABL core complex.

  • Epigenetic modifications working in the decidualization and endometrial receptivity
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-07
    Hong Liu, Xiaobo Huang, Gil Mor, Aihua Liao

    Decidualization is a critical event for the blastocyst implantation, placental development and fetal growth and the normal term. In mice, the embryo implantation to the uterine epithelial would trigger the endometrial stromal cells to differentiate into decidual stromal cells. However, decidualization in women takes place from the secretory phase of each menstrual cycle and continues to early pregnancy if there is conceptus. Deficient decidualization is often associated with pregnancy specific complications and reproductive disorders. Dramatic changes occur in the gene expression profiles during decidualization, which is coordinately regulated by steroid hormones, growth factors, and molecular and epigenetic mechanisms. Recently, emerging evidences showed that epigenetic modifications, mainly including DNA methylation, histone modification, and non-coding RNAs, play an important role in the decidualization process via affecting the target genes’ expression. In this review, we will focus on the epigenetic modifications in decidualization and open novel avenues to predict and treat the pregnancy complications caused by abnormal decidualization.

  • The one thousand and one chaperones of the NF-κB pathway
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-06
    Federica Fusella, Laura Seclì, Cristiana Cannata, Mara Brancaccio

    The NF-κB pathway represents a crucial signaling mechanism in sensing and integrating a multitude of environmental and intracellular stimuli and directing a coordinated response that from the cellular level may impact on the entire organism. A plethora of chaperone proteins work at multiple steps of the pathway, from membrane receptor activation to transcription factor binding to DNA. Indeed, chaperones are required to assist protein conformational changes, to assemble supramolecular complexes and to regulate protein ubiquitination, required for pathway activation. Some chaperones acquired a role as integral components of the signaling complexes, needed for signal progression. Here we describe the chaperones involved in the NF-κB pathway and their specific roles in the different contexts.

  • Control of cell fate during axillary meristem initiation
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-06
    Xiuwei Cao, Yuling Jiao

    Axillary meristems (AMs) are located in the leaf axil and can establish new growth axes. Whereas their neighboring cells are differentiated, the undifferentiated cells in the AM endow the AM with the same developmental potential as the shoot apical meristem. The AM is, therefore, an excellent system to study stem cell fate maintenance in plants. In this review, we summarize the current knowledge of AM initiation. Recent findings have shown that AMs derive from a stem cell lineage that is maintained in the leaf axil. This review covers AM progenitor cell fate maintenance, reactivation, and meristem establishment. We also highlight recent work that links transcription factors, phytohormones, and epigenetic regulation to AM initiation.

  • Exotoxins from Staphylococcus aureus activate 5-lipoxygenase and induce leukotriene biosynthesis
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-05
    Erik Romp, Vandana Arakandy, Jana Fischer, Christiane Wolz, Anke Siegmund, Bettina Löffler, Lorena Tuchscherr, Oliver Werz, Ulrike Garscha

    Massive neutrophil infiltration is an early key event in infectious inflammation, accompanied by chemotactic leukotriene (LT)B4 generation. LTB4 biosynthesis is mediated by 5-lipoxygenase (5-LOX), but which pathogenic factors cause 5-LOX activation during bacterial infections is elusive. Here, we reveal staphylococcal exotoxins as 5-LOX activators. Conditioned medium of wild-type Staphylococcus aureus but not of exotoxin-deficient strains induced 5-LOX activation in transfected HEK293 cells. Two different staphylococcal exotoxins mimicked the effects of S. aureus-conditioned medium: (1) the pore-forming toxin α-hemolysin and (2) amphipathic α-helical phenol-soluble modulin (PSM) peptides. Interestingly, in human neutrophils, 5-LOX activation was exclusively evoked by PSMs, which was prevented by the selective FPR2/ALX receptor antagonist WRW4. 5-LOX activation by PSMs was confirmed in vivo as LT formation in infected paws of mice was impaired in response to PSM-deficient S. aureus. Conclusively, exotoxins from S. aureus are potent pathogenic factors that activate 5-LOX and induce LT formation in neutrophils.

  • The triple role of glutathione S-transferases in mammalian male fertility
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-05
    Marc Llavanera, Yentel Mateo-Otero, Sergi Bonet, Isabel Barranco, Beatriz Fernández-Fuertes, Marc Yeste

    Male idiopathic infertility accounts for 15–25% of reproductive failure. One of the factors that has been linked to this condition is oxidative stress (OS), defined as the imbalance between antioxidants and reactive oxygen species. Amongst the different factors that protect the cell against OS, the members of the glutathione S-transferase (GST) superfamily play an important role. Interestingly, reduction or lack of some GSTs has been associated to infertility in men. Therefore, and to clarify the relationship between GSTs and male fertility, the aim of this work is to describe the role that GSTs play in the male reproductive tract and in sperm physiology. To that end, the present review provides a novel perspective on the triple role of GSTs (detoxification, regulation of cell signalling and fertilisation), and reports their localisation in sperm, seminal plasma and the male reproductive tract. Furthermore, we also tackle the existing correlation between some GST classes and male fertility. Due to the considerable impact of GSTs in human pathology and their tight relationship with fertility, future research should address the specific role of these proteins in male fertility, which could result in new approaches for the diagnosis and/or treatment of male infertility.

  • Stem cell-derived kidney organoids: engineering the vasculature
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-05
    Marije Koning, Cathelijne W. van den Berg, Ton J. Rabelink

    Kidney organoids can be generated from human pluripotent stem cells (PSCs) using protocols that resemble the embryonic development of the kidney. The renal structures thus generated offer great potential for disease modeling, drug screening, and possibly future therapeutic application. At the same time, use of these PSC-derived organoids is hampered by lack of maturation and off-target differentiation. Here, we review the main protocols for the generation of kidney organoids from human-induced PSCs, discussing their advantages and limitations. In particular, we will focus on the vascularization of the kidney organoids, which appears to be one of the critical factors to achieve maturation and functionality of the organoids.

  • Driving the catalytic activity of a transmembrane thermosensor kinase
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-04
    María Eugenia Inda, Juan Cruz Almada, Daniela Belén Vazquez, Ana Bortolotti, Ariel Fernández, Jean Marie Ruysschaert, Larisa Estefanía Cybulski

    DesK is a Bacillus thermosensor kinase that is inactive at high temperatures but turns activated when the temperature drops below 25 °C. Surprisingly, the catalytic domain (DesKC) lacking the transmembrane region is more active at higher temperature, showing an inverted regulation regarding DesK. How does the transmembrane region control the catalytic domain, repressing activity at high temperatures, but allowing activation at lower temperatures? By designing a set of temperature minimized sensors that share the same catalytic cytoplasmic domain but differ in number and position of hydrogen-bond (H-bond) forming residues along the transmembrane helix, we are able to tune, invert or disconnect activity from the input signal. By favoring differential H-bond networks, the activation peak could be moved towards lower or higher temperatures. This principle may be involved in regulation of other sensors as environmental physicochemical changes or mutations that modify the transmembrane H-bond pattern can tilt the equilibrium favoring alternative conformations.

  • Amyotrophic lateral sclerosis-linked UBQLN2 mutants inhibit endoplasmic reticulum to Golgi transport, leading to Golgi fragmentation and ER stress
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-04
    Mark Halloran, Audrey M. G. Ragagnin, Marta Vidal, Sonam Parakh, Shu Yang, Benjamin Heng, Natalie Grima, Hamideh Shahheydari, Kai-Ying Soo, Ian Blair, Gilles J. Guillemin, Vinod Sundaramoorthy, Julie D. Atkin

    Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are fatal neurodegenerative diseases that are related genetically and pathologically. Mutations in the UBQLN2 gene, encoding the ubiquitin-like protein ubiquilin2, are associated with familial ALS/FTD, but the pathophysiological mechanisms remain unclear. Here, we demonstrate that ALS/FTD UBQLN2 mutants P497H and P506T inhibit protein transport from the endoplasmic reticulum (ER) to the Golgi apparatus in neuronal cells. In addition, we observed that Sec31-positive ER exit sites are clustered in UBQLN2T487I patient spinal cord tissues. Both the ER–Golgi intermediate (ERGIC) compartment and the Golgi become disorganised and fragmented. This activates ER stress and inhibits ER-associated degradation. Hence, this study highlights perturbations in secretory protein trafficking and ER homeostasis as pathogenic mechanisms associated with ALS/FTD-associated forms of UBQLN2.

  • A role of cellular translation regulation associated with toxic Huntingtin protein
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-12-03
    Hiranmay Joag, Vighnesh Ghatpande, Meghal Desai, Maitheli Sarkar, Anshu Raina, Mrunalini Shinde, Ruta Chitale, Ankita Deo, Tania Bose, Amitabha Majumdar

    Huntington’s disease (HD) is a severe neurodegenerative disorder caused by poly Q repeat expansion in the Huntingtin (Htt) gene. While the Htt amyloid aggregates are known to affect many cellular processes, their role in translation has not been addressed. Here we report that pathogenic Htt expression causes a protein synthesis deficit in cells. We find a functional prion-like protein, the translation regulator Orb2, to be sequestered by Htt aggregates in cells. Co-expression of Orb2 can partially rescue the lethality associated with poly Q expanded Htt. These findings can be relevant for HD as human homologs of Orb2 are also sequestered by pathogenic Htt aggregates. Our work suggests that translation dysfunction is one of the contributors to the pathogenesis of HD and new therapies targeting protein synthesis pathways might help to alleviate disease symptoms.

  • Regulation of AMPK activity by type 10 adenylyl cyclase: contribution to the mitochondrial biology, cellular redox and energy homeostasis
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-06-06
    Vignesh Jayarajan, Avinash Appukuttan, Muhammad Aslam, Peter Reusch, Vera Regitz-Zagrosek, Yury Ladilov

    The downregulation of AMP-activated protein kinase (AMPK) activity contributes to numerous pathologies. Recent reports suggest that the elevation of cellular cAMP promotes AMPK activity. However, the source of the cAMP pool that controls AMPK activity remains unknown. Mammalian cells possess two cAMP sources: membrane-bound adenylyl cyclase (tmAC) and intracellularly localized, type 10 soluble adenylyl cyclase (sAC). Due to the localization of sAC and AMPK in similar intracellular compartments, we hypothesized that sAC may control AMPK activity. In this study, sAC expression and activity were manipulated in H9C2 cells, adult rat cardiomyocytes or endothelial cells. sAC knockdown depleted the cellular cAMP content and decreased AMPK activity in an EPAC-dependent manner. Functionally, sAC knockdown reduced cellular ATP content, increased mitochondrial ROS formation and led to mitochondrial depolarization. Furthermore, sAC downregulation led to EPAC-dependent mitophagy disturbance, indicated by an increased mitochondrial mass and unaffected mitochondrial biogenesis. Consistently, sAC overexpression or stimulation with bicarbonate significantly increased AMPK activity and cellular ATP content. In contrast, tmAC inhibition or stimulation produced no effect on AMPK activity. Therefore, the sAC–EPAC axis may regulate basal and induced AMPK activity and support mitophagy, cellular energy and redox homeostasis. The study argues for sAC as a potential target in treating pathologies associated with AMPK downregulation.

  • Protein interacting with Amyloid Precursor Protein tail-1 (PAT1) is involved in early endocytosis
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-05-28
    Aysegul Dilsizoglu Senol, Lidia Tagliafierro, Lucie Gorisse-Hussonnois, Florian Rebeillard, Léa Huguet, David Geny, Vincent Contremoulins, Fabian Corlier, Marie-Claude Potier, Stéphanie Chasseigneaux, Michèle Darmon, Bernadette Allinquant

    Protein interacting with Amyloid Precursor Protein (APP) tail 1 (PAT1) also called APPBP2 or Ara 67 has different targets such as APP or androgen receptor and is expressed in several tissues. PAT1 is known to be involved in the subcellular trafficking of its targets. We previously observed in primary neurons that PAT1 is poorly associated with APP at the cell surface. Here we show that PAT1 colocalizes with vesicles close to the cell surface labeled with Rab5, Rab4, EEA1 and Rabaptin-5 but not with Rab11 and Rab7. Moreover, PAT1 expression regulates the number of EEA1 and Rab5 vesicles, and endocytosis/recycling of the transferrin receptor. In addition, low levels of PAT1 decrease the size of transferrin-colocalized EEA1 vesicles with time following transferrin uptake. Finally, overexpression of the APP binding domain to PAT1 is sufficient to compromise endocytosis. Altogether, these data suggest that PAT1 is a new actor in transferrin early endocytosis. Whether this new function of PAT1 may have consequences in pathology remains to be determined.

  • The PCNA interaction motifs revisited: thinking outside the PIP-box
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-05-27
    Andreas Prestel, Nanna Wichmann, Joao M. Martins, Riccardo Marabini, Noah Kassem, Sebastian S. Broendum, Marit Otterlei, Olaf Nielsen, Martin Willemoës, Michael Ploug, Wouter Boomsma, Birthe B. Kragelund

    Proliferating cell nuclear antigen (PCNA) is a cellular hub in DNA metabolism and a potential drug target. Its binding partners carry a short linear motif (SLiM) known as the PCNA-interacting protein-box (PIP-box), but sequence-divergent motifs have been reported to bind to the same binding pocket. To investigate how PCNA accommodates motif diversity, we assembled a set of 77 experimentally confirmed PCNA-binding proteins and analyzed features underlying their binding affinity. Combining NMR spectroscopy, affinity measurements and computational analyses, we corroborate that most PCNA-binding motifs reside in intrinsically disordered regions, that structure preformation is unrelated to affinity, and that the sequence-patterns that encode binding affinity extend substantially beyond the boundaries of the PIP-box. Our systematic multidisciplinary approach expands current views on PCNA interactions and reveals that the PIP-box affinity can be modulated over four orders of magnitude by positive charges in the flanking regions. Including the flanking regions as part of the motif is expected to have broad implications, particularly for interpretation of disease-causing mutations and drug-design, targeting DNA-replication and -repair.

  • Proinflammatory NFkB signalling promotes mitochondrial dysfunction in skeletal muscle in response to cellular fuel overloading
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-05-17
    Raid B. Nisr, Dinesh S. Shah, Ian G. Ganley, Harinder S. Hundal

    Sustained nutrient (fuel) excess, as occurs during obesity and diabetes, has been linked to increased inflammation, impaired mitochondrial homeostasis, lipotoxicity, and insulin resistance in skeletal muscle. Precisely how mitochondrial dysfunction is initiated and whether it contributes to insulin resistance in this tissue remains a poorly resolved issue. Herein, we examine the contribution that an increase in proinflammatory NFkB signalling makes towards regulation of mitochondrial bioenergetics, morphology, and dynamics and its impact upon insulin action in skeletal muscle cells subject to chronic fuel (glucose and palmitate) overloading. We show sustained nutrient excess of L6 myotubes promotes activation of the IKKβ-NFkB pathway (as judged by a six-fold increase in IL-6 mRNA expression; an NFkB target gene) and that this was associated with a marked reduction in mitochondrial respiratory capacity (>50%), a three-fold increase in mitochondrial fragmentation and 2.5-fold increase in mitophagy. Under these circumstances, we also noted a reduction in the mRNA and protein abundance of PGC1α and that of key mitochondrial components (SDHA, ANT-1, UCP3, and MFN2) as well as an increase in cellular ROS and impaired insulin action in myotubes. Strikingly, pharmacological or genetic repression of NFkB activity ameliorated disturbances in mitochondrial respiratory function/morphology, attenuated loss of SDHA, ANT-1, UCP3, and MFN2 and mitigated the increase in ROS and the associated reduction in myotube insulin sensitivity. Our findings indicate that sustained oversupply of metabolic fuel to skeletal muscle cells induces heightened NFkB signalling and that this serves as a critical driver for disturbances in mitochondrial function and morphology, redox status, and insulin signalling.

  • Microbiome–metabolomics reveals gut microbiota associated with glycine-conjugated metabolites and polyamine metabolism in chronic kidney disease
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2019-05-30
    Ya-Long Feng, Gang Cao, Dan-Qian Chen, Nosratola D. Vaziri, Lin Chen, Jun Zhang, Ming Wang, Yan Guo, Ying-Yong Zhao

    Dysbiosis of the gut microbiome and related metabolites in chronic kidney disease (CKD) have been intimately associated with the prevalence of cardiovascular diseases. Unfortunately, thus far, there is a paucity of sufficient knowledge of gut microbiome and related metabolites on CKD progression partly due to the severely limited investigations. Using a 5/6 nephrectomized (NX) rat model, we carried out 16S rRNA sequence and untargeted metabolomic analyses to explore the relationship between colon’s microbiota and serum metabolites. Marked decline in microbial diversity and richness was accompanied by significant changes in 291 serum metabolites, which were mediated by altered enzymatic activities and dysregulations of lipids, amino acids, bile acids and polyamines metabolisms. Interestingly, CCr was directly associated with some microbial genera and polyamine metabolism. However, SBP was directly related to certain microbial genera and glycine-conjugated metabolites in CKD rats. Administration of poricoic acid A (PAA) and Poria cocos (PC) ameliorated microbial dysbiosis as well as attenuated hypertension and renal fibrosis. In addition, treatments with PAA and PC lowered serum levels of microbial-derived products including glycine-conjugated compounds and polyamine metabolites. Collectively, the present study confirmed the CKD-associated gut microbial dysbiosis and identified a novel dietary and therapeutic strategy to improve the gut microbial dysbiosis and the associated metabolomic disorders and retarded the progression of kidney disease in the rat model of CKD.

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上海纽约大学William Glover