Epigenetics in the early divergent eukaryotic Giardia duodenalis: an update Biochimie (IF 3.188) Pub Date : 2018-10-19 Francisco Alejandro Lagunas-Rangel, Rosa María Bermúdez-Cruz
Giardia duodenalis is a flagellated unicellular eukaryotic microorganism that usually parasitizes the small intestine of humans and many other vertebrates causing diarrheal disease throughout the world. Notably, Giardia despite minimization of most cellular systems shows different strategies to adapt to environmental conditions, evade the immune system and resist exposure to antimicrobial agents. Over the past years, epigenetic regulation of gene expression has been shown to have a relevant role in the parasite’s biology. Interestingly, analysis of the Giardia genome revealed the presence of enzymes responsible for post-translational modification in histones, therefore suggesting that epigenetic mechanisms may regulate gene expression in this parasite. Thus, the purpose of this review is to summarize how epigenetic mechanisms play relevant roles in the pathogenicity of Giardia, with a particular emphasis on the molecular mechanisms associated with parasite differentiation, antigenic variation and antimicrobial resistance.
High altitude mediated skeletal muscle atrophy: Protective role of curcumin Biochimie (IF 3.188) Pub Date : 2018-10-19 Pooja Chaudhary, Yogendra Kumar Sharma, Shivani Sharma, Som Nath Singh, Geetha Suryakumar
Chronic hypobaric hypoxia induced muscle atrophy results in decreased physical performance at high altitude. Curcumin has been shown to have muscle sparing effects under cachectic conditions. However, the protective effects of curcumin under chronic hypobaric hypoxia have not been studied till now. Therefore, the present study aims at evaluating the effects of curcumin administration on muscle atrophy under chronic hypobaric hypoxia. Male Sprague Dawley rats were divided into four groups: Control (C)-normoxia exposed, Control Treated (CT)-normoxia exposed and administered with curcumin at a dose of 100 mg/kg body weight for 14 days, Hypoxia (H)-exposed to hypobaric hypoxia for 14 days and Hypoxia Treated (HT)-exposed to hypobaric hypoxia and administered with curcumin for 14 days. Oxidative stress, muscle protein degradation, proteolytic pathways, myosin heavy chain (MHC), CPK activity and muscle histology were performed in gastrocnemius muscle samples of the exposed rats. In addition, fatigue time on treadmill running was also evaluated to observe the effects of curcumin administration on physical performance of the rats. As previously shown, hypobaric hypoxia increased muscle protein degradation via upregulated calpain and ubiquitin-proteolytic pathways. An enhanced oxidative stress has been linked to upregulation of these pathways under hypoxic conditions. Curcumin administration resulted in reduced oxidative stress as well as reduced activity of the proteolytic pathways in HT group as compared to H group thereby resulting in reduced muscle protein degradation under hypobaric hypoxia. Histology of rat muscle revealed an increased number of muscle fibres in HT as compared to H group. Thus, increased number of muscle fibres and decreased muscle proteolysis following curcumin administration, lead to enhanced muscle mass under hypobaric hypoxia resulting in improved physical performance of the rats.
LncRNA ANRIL promotes NLRP3 inflammasome activation in uric acid nephropathy through miR-122-5p/BRCC3 axis Biochimie (IF 3.188) Pub Date : 2018-10-19 Jiacai Hu, Hao Wu, Daochun Wang, Zhijie Yang, Junjun Dong
This study is designed to explore the mechanism by which long non-coding RNA (lncRNA) antisense non-coding RNA in the INK4 locus (ANRIL) plays a pathogenic role in uric acid nephropathy (UAN). The expressions of ANRIL, miR-122-5p, BRCA1-BRCA2-containing complex subunit 3 (BRCC3) and NOD-like receptor protein 3 (NLRP3) were determined in UAN patients and uric acid-treated HK-2 cells by qRT-PCR. Protein levels of BRCC3 and NLRP3 were examined by western blot. The levels of inflammatory cytokines were quantified by ELISA. CCK-8 assay was used to assess cell viability. Apoptosis was detected by Annexin V-FITC/PI double-labeled flow cytometry and TUNEL assay. The interaction between ANRIL, miR-122-5p and BRCC3 were studied using luciferase reporter assay. The role of ANRIL in renal injury was evaluated in experimental rats. ANRIL and BRCC3 were highly expressed while miR-122-5p was down-regulated in serum of UAN patients and uric acid-treated tubular epithelial cells. Luciferase reporter assay and in vitro rescue experiment confirmed that ANRIL promoted NLRP3 inflammasome activation by up-regulating BRCC3 expression via sponging miR-122-5p. Furthermore, in vivo experiment validated that knockdown of ANRIL alleviated renal injury of UAN rats. ANRIL exerted pathogenic effect in UAN to promote NLRP3 inflammasome activation via miR-122-5p/BRCC3 axis.
Neuroprotective effects of Tat-ATOX1 protein against MPP+-induced SH-SY5Y cell deaths and in MPTP-induced mouse model of Parkinson’s disease Biochimie (IF 3.188) Pub Date : 2018-10-21 Won Sik Eum, Min Jea Shin, Chi Hern Lee, Hyeon Ji Yeo, Eun Ji Yeo, Yeon Joo Choi, Hyun Jung Kwon, Duk-Soo Kim, Oh Shin Kwon, Keun Wook Lee, Kyu Hyung Han, Jinseu Park, Dae Won Kim, Soo Young Choi
Parkinson’s disease (PD), a neurodegenerative disorder, is characterized by a loss of dopaminergic neurons in the substantia nigra (SN) of the brain and it is well known that the pathogenesis of PD is related to a number of risk factors including oxidative stress. Antioxidant 1 (ATOX1) protein plays a crucial role in various diseases as an antioxidant and chaperone. In this study, we determined whether Tat-ATOX1 could protect against 1-methyl-4-phenylpyridinium ion (MPP+)-induced SH-SY5Y cell death and in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced animal model of PD. In the MPP+ exposed SH-SY5Y cells, Tat-ATOX1 markedly inhibited cell death and toxicities. In addition, Tat-ATOX1 markedly suppressed the activation of Akt and mitogen activated protein kinases (MAPKs) as well as cleavage of caspase-3 and Bax expression levels. In a MPTP-induced animal model, Tat-ATOX1 transduced into brain and protected dopaminergic neuronal cell loss. Taken together, Tat-ATOX1 inhibits dopaminergic neuronal death through the suppression of MAPKs and apoptotic signal pathways. Thus, Tat-ATOX1 represents a potential therapeutic protein drug candidate for PD.
Ferrochelatase activity of plant frataxin Biochimie (IF 3.188) Pub Date : 2018-10-18 Alejandro M. Armas, Manuel Balparda, Agustina Terenzi, Maria V. Busi, Maria A. Pagani, Diego F. Gomez-Casati
Frataxin plays a key role in cellular iron homeostasis of different organisms. It is engaged in several activities at the Fe-S cluster assembly machinery and it is also involved in heme biosynthesis. In plants, two genes encoding ferrochelatases (FC1 and FC2) catalyze the incorporation of iron into protoporphyrin IX in the last stage of heme synthesis in chloroplasts. Despite ferrochelatases are absent from other cell compartments, a remaining ferrochelatase activity has been observed in plant mitochondria. Here we analyze the possibility that frataxin acts as the iron donor to protoporphyrin IX for the synthesis of heme groups in plant mitochondria. Our findings show that frataxin catalyzes the formation of heme in vitro when it is incubated with iron and protoporphyrin IX. When frataxin is combined with AtNFS1 and AtISD11 the ferrochelatse activity is increased. These results suggest that frataxin could be the iron donor in the final step of heme synthesis in plant mitochondria, and constitutes an important advance in the elucidation of the mechanisms of heme synthesis in plants.
Influence of Passage Number on the Impact of the Secretome of Adipose Tissue Stem Cells on Neural Survival, Neurodifferentiation and Axonal Growth Biochimie (IF 3.188) Pub Date : 2018-10-17 Sofia C. Serra, João C. Costa, Rita C. Assunção-Silva, Fábio G. Teixeira, Nuno A. Silva, Sandro I. Anjo, Bruno Manadas, Jeffrey Gimble, Leo A. Behie, António J. Salgado
Mesenchymal stem cells (MSCs), and within them adipose tissue derived stem cells (ASCs), have been shown to have therapeutic effects on central nervous system (CNS) cell populations. Such effects have been mostly attributed to soluble factors, as well as vesicles, present in their secretome. Yet, little is known about the impact that MSC passaging might have in the secretion therapeutic profile. Our aim was to show how human ASCs (hASCs) passage number influences the effect of their secretome in neuronal survival, differentiation and axonal growth. For this purpose, post-natal rat hippocampal primary cultures, human neural progenitor cell (hNPCs) cultures and dorsal root ganglia (DRGs) explants were incubated with secretome, collected as conditioned media (CMs), obtained from hASCs in P3, P6, P9 and P12. Results showed no differences when comparing percentages of MAP-2 positive cells (a mature neuronal marker) in neuronal cultures or of hNPCs that differentiated, after incubation with hASCs secretome from different passages. The same was observed regarding DRG neurite outgrowth. In order to characterize the secretomes obtained from different passages, a proteomic analysis was performed, revealing that its composition did not vary significantly with passage number P3 to P12. Results allowed us to identify several key proteins, such as pigment epithelium derived factor (PEDF), DJ-1, interleucin-6 (IL-6) and galectin, all of which have already proven to play neuroprotective and neurodifferentiating roles. Proteins that promote neurite outgrowth were also found present, such as semaphorin 7A and glypican-1. We conclude that cellular passaging does not influence significantly hASC’s secretome properties especially their ability to support post-natal neuronal survival, induce neurodifferentiation and promote axonal growth.
Self-association and folding in membrane determine the mode of action of peptides from the lytic segment of sticholysins Biochimie (IF 3.188) Pub Date : 2018-10-13 Uris Ros, Gustavo P.B. Carretero, Joana Paulino, Edson Crusca, Fabiola Pazos, Eduardo M. Cilli, Maria E. Lanio, Shirley Schreier, Carlos Alvarez
Stabilization of miRNAs in esophageal cancer contributes to radioresistance and limits efficacy of therapy Biochimie (IF 3.188) Pub Date : 2018-10-13 Akshay Malhotra, Uttam Sharma, Shyamly Puhan, Naga Chandra Bandari, Anjali Kharab, P.P Arifa, Lovlesh Thakur, Hridayesh Prakash, Karen M. Vasquez, Aklank Jain
The five-year survival rate of esophageal cancer patients is less than 20%. This may be due to increased resistance (acquired or intrinsic) of tumor cells to chemo/radiotherapies, often caused by aberrant cell cycle, deregulated apoptosis, increases in growth factor signaling pathways, and/or changes in the proteome network. In addition, deregulation in non-coding RNA-mediated signaling pathways may contribute to resistance to therapies. At the molecular level, these resistance factors have now been linked to various microRNA (miRNAs), which have recently been shown to control cell development, differentiation and neoplasia. The increased stability and dysregulated expression of miRNAs have been associated with increased resistance to various therapies in several cancers, including esophageal cancer. Therefore, miRNAs represent the next generation of molecules with tremendous potential as biomarkers and therapeutic targets. Yet, a detailed studies on miRNA-based therapeutic intervention is still in its infancy. Hence, in this review, we have summarized the current status of microRNAs in dictating the resistance/sensitivity of tumor cells against chemotherapy and radiotherapy. In addition, we have discussed various strategies to increase radiosensitivity, including targeted therapy, and the use of miRNAs as radiosensitive/radioresistance biomarkers for esophageal cancer in the clinical setting.
Activation of catalase via co-administration of aspirin and pioglitazone: Experimental and MLSD simulation approaches Biochimie (IF 3.188) Pub Date : 2018-10-14 Yunes Panahi, Reza Yekta, Gholamreza Dehghan, Samaneh Rashtbari, Nematollah Jonaidi Jafari, Ali A. Moosavi-Movahedi
Aspirin (ASP) and pioglitazone (PGL) are the most common drugs that are widely used by diabetic patients to control the blood sugar and hinder cardiovascular diseases. The interaction between PGL and ASP is one of the important medical issues to clarify the safety of co-administration of these drugs. In the present study, the effect of co-administered ASP with PGL was investigated on the structure and catalytic function of catalase as a potential target in the liver. Based on our data, co-administration of ASP-PGL significantly enhanced the catalase activity in comparison with PGL alone. However, ASP does not have any effects on the catalytic function of catalase. Moreover, the dialysis measurement and CD spectroscopy study revealed that binding of ASP to catalase could increase the stability of catalase-PGL complex. Based on the obtained data, it is shown that the binding of ASP to catalase led to increase the affinity of catalase to PGL. Binding analysis showed that the association constant of catalase-PGL was reduced considerably in the presence of ASP from 12.19 ±0. 1×106 M-1 to 6.4 ±0. 2×106 M-1 at 298K. Multiple ligands simultaneous docking (MLSD) also confirmed an increase in the binding affinity of PGL to catalase.
Fragmentation of Escherichia coli mRNA by MazF and MqsR Biochimie (IF 3.188) Pub Date : 2018-10-10 Toomas Mets, Sergo Kasvandik, Merilin Saarma, Ülo Maiväli, Tanel Tenson, Niilo Kaldalu
MazEF and MqsRA are toxin-antitoxin systems, where the toxins MazF and MqsR sequence-specifically cleave single-stranded RNA, thereby shutting down protein synthesis and cell growth. However, it has been proposed that MazF functions in a highly specific pathway, where it truncates the 5’ ends of a set of E. coli transcripts (the MazF regulon), which are then translated under stress conditions by specialized ribosomes. We mapped the cleavage sites of MazF and MqsR throughout the E. coli transcriptome. Our results show that both toxins cleave mRNA independently of the recognition site position and MazF freely cleaves transcripts of the proposed MazF regulon within coding sequences. Proteome analysis indicated that MazF expression leads to overall inhibition of protein synthesis and the putative MazF regulon proteins are not selectively synthesized in response to the toxin. Our results support a simpler role for endoribonuclease TA systems as indifferent destroyers of unstructured RNA.
Lysines residing in putative small ubiquitin-like modifier (SUMO) motifs regulate fate and function of 37 KDa Laminin Receptor Biochimie (IF 3.188) Pub Date : 2018-10-10 Charles Samuel Umbaugh, Marxa L. Figueiredo
There is a putative precursor to a mature receptor relationship between 37 Laminin Receptor (LR) and 67 LR. As such, the pair are frequently referred to as a single entity, the 37/67 kDa Laminin Receptor (37/67 LR) and 67 LR was identified as a laminin binding entity. 37/67 LR has been of clinical interest for many years, as 37/67 LR is a prognostic indicator for many cancers including breast, lung, colon, and prostate. However, the genesis of 67LR is controversial, and confounded by its stability under SDS-PAGE conditions, a lack of splice variants, and the existence of post-translational modifications that cannot account for the mass discrepancy between 37 and 67 LR. In the present work, we mutated potential SUMO motif sites (Lysine residues) in 37 LR and generated a series of 37 LR-expressing plasmids with a C-terminal histidine tag. We report an inability to detect 67 LR formation, suggesting that SUMOylation does not appear to directly occur at the lysine residues proposed. However, the work revealed that these lysine mutations still appear to be important and can impact the fate and function for 37 LR, for example impairing half-life and steady state pre-mRNA levels. These results suggest that the Lys residues within putative SUMO motifs in 37 LR may indirectly coordinate with SUMO pathways.
α-Lipoic acid and Amlodipine/Perindopril combination potentiate the therapeutic effect of mesenchymal stem cells on Isoproterenol induced cardiac injury in rats Biochimie (IF 3.188) Pub Date : 2018-10-08 Abeer I. Abd El-Fattah, M.S. Zaghloul, N.A. Eltablawy, L.A. Rashed
Cardiac injury is a dangerous disease and become a greater issue in the forthcoming decades. The ultimate goal is to prevent the progression of heart failure and apoptotic processes. Cardiac tissue may regenerate itself but to certain extent depending on the number of resident stem cells that is limited. Thus, research had been focused on bone marrow derived stem cells (BM-MSCs) as a promising therapy in different types of tissues, including the heart. This study is designed not only to assess the therapeutic effect of BM-MSCs but also to improve their therapeutic effect in combination with antioxidant α-lipoic acid (ALA) and antihypertensive therapeutic drug form (AP) against isoproterenol-induced cardiac injury and compared with that of BM-MSCs alone. Cardiac injury was induced in 70 male rats by Isoproterenol (ISO was injected s.c. for four consecutive days). Experimental animals were divided into six ISO-treated groups beside a control non treated one. The six ISO-treated groups were divided into: ISO group, ISO+BM-MSCs group, ISO+ALA group, ISO+AP group, ISO+ALA+AP group and ISO+ALA+AP+BM-MSCs group, the last five groups were treated with the examined materials after one week of ISO injection. Isoproterenol significantly increased serum CK-MB, LDH activities, Troponin1 and TNF-α. Oxidative stress is evidenced by the increased MDA, NO and Caspase-3 activity associated with significant reduction of GSH content and SOD activity in cardiac tissue. Furthermore, mRNA expression of NFκB and iNOS were significantly up regulated and eNOS mRNA expression was down regulated. Administration of BM-MSCs, ALA and AP alone significantly mitigated the induced cardiac injury. Concomitant administration of ALA and AP after BM-MSCs induced a more pronounced improving effect on cardiac functions. In conclusion, the concomitant administration of ALA and AP after BM-MSCs infusion increases the cellular antioxidant levels of cardiac tissue that improves the repairing function of BM-MSCs.
MiR-650 regulates the proliferation, migration and invasion of human oral cancer by targeting Growth factor independent 1 (Gfi1) Biochimie (IF 3.188) Pub Date : 2018-10-06 Sun Ningning, Sun Libo, Wu Chuanbin, Sun Haijiang, Zhou Qing
Oral cancer being one of the lethal cancers is generally detected at advanced stages and causes significant mortality world over. The unavailability of the reliable biomarkers and therapeutic targets/agents forms a bottleneck in the treatment of oral cancer. MicroRNAs are considered of immense therapeutic potential for the treatment of cancer. Consistently, in this study the role and therapeutic potential of miR-650 was explored in oral cancer. The analysis of miR-650 expression by qRT-PCR revealed significant (p < 0.05) upregulation of miR-650 in oral cancer cell lines. Cell cycle analysis by flow cytometery revealed that suppression of miR-650 significantly (p < 0.05) inhibits the proliferation of the SCC-25 cells by prompting Sub-G1 cell cycle arrest. Further, miR-650 suppression also inhibited the migration and invasion of the SCC-25 oral cancer cells as revealed by transwell assays. TargetScan analysis showed that miR-650 targets Growth factor independent 1 (Gfi1). Moreover, the results of western blot analysis showed that miR-650 suppression inhibits the expression of Gfi1. Interestingly, suppression of Gfi1 exhibited similar effects on cell proliferation, migration and invasion of the oral cancer cells as that of miR-650 suppression. Nonetheless, miR-650 promoted the proliferation, migration and invasion of the SCC-25 cells by upregulating the expression of Gfi1. Moreover, overexpression of miR-650 could not rescue the effects of Gfi1 silencing on SCC-25 oral cancer cells. Conversely, overexpression of Gfi1 could rescue the effects of miR-650 inhibition on SCC-25 cell proliferation, migration and invasion. Additionally, miR-650 suppression could also inhibit the xenografted tumor growth in vivo by inhibiting the expression of Gfi1. Taken together, miR-650 may prove to be an important therapeutic target for the management of oral cancers.
Chronic whole-body heat treatment relieves atherosclerotic lesions, cardiovascular and metabolic abnormalities, and enhances survival time restoring the anti-inflammatory and anti-senescent heat shock response in mice Biochimie (IF 3.188) Pub Date : 2018-09-28 Maciel Alencar Bruxel, Angela Maria Vicente Tavares, Luiz Domingues Zavarize Neto, Victor de Souza Borges, Helena Trevisan Schroeder, Patricia Martins Bock, Maria Inês Lavina Rodrigues, Adriane Belló-Klein, Paulo Ivo Homem de Bittencourt
Pro-inflammatory effects of extracellular Hsp70 and cigarette smoke in primary airway epithelial cells from COPD patients Biochimie (IF 3.188) Pub Date : 2018-09-27 Andrea Hulina-Tomašković, Irene H. Heijink, Marnix R. Jonker, Anita Somborac-Bačura, Marija Grdić Rajković, Lada Rumora
Extracellular Hsp70 (eHsp70) can activate immune cells via Toll-like receptors (TLR) 2 and 4, and induce cytokine synthesis. The aim of this study was to explore inflammation-associated effects of eHsp70 alone and in combination with cigarette smoke extract (CSE) in primary bronchial epithelial cells.We assessed IL-6 and IL-8 concentrations, TLR2, TLR4 and Hsp70 mRNA expressions, and mitogen-activated protein kinases (MAPKs) activation induced by recombinant human (rh) Hsp70, CSE or their combinations in normal human bronchial epithelial cells (NHBE) obtained commercially, and primary bronchial epithelial cells isolated from non-COPD lung donors (PBEC) or COPD patients (PBEC COPD).Baseline levels of IL-6 and IL-8 were significantly higher in PBEC COPD than in non-COPD PBECs. Upon rhHsp70 stimulation, IL-6 and IL-8 were significantly increased, with the strongest response in COPD-derived PBECs. CSE alone elevated cytokine secretion in all examined cells. rhHsp70 and CSE had antagonistic interactions on IL-8 release in PBECs from COPD patients, while the addition of rhHsp70 further increased CSE-induced IL-6 secretion in NHBE cells. rhHsp70 and CSE alone decreased TLR2 and TLR4 mRNA expression in COPD-derived PBECs. In non-COPD PBECs, combined treatments decreased only TLR2 mRNA expression. Hsp70 mRNA expression, as indicator of intracellular Hsp70, which may have anti-inflammatory effects, was reduced in COPD-derived cells upon exposure to CSE and rhHsp70 alone, but not with their combinations. Contrary to this, in PBECs from lung donors only combined treatments supressed Hsp70 gene expression. CSE activated JNK and p38 MAPKs, while rhHsp70 increased activation of c-Jun kinase in NHBE cells.Collectively, both eHsp70 and CSE induce pro-inflammatory responses in PBECs from non-COPD as well as COPD donors, but in combination antagonistic effects were observed in COPD-derived cells. These effects may be related to the regulation of TLR2/4 and might lead to modulation of inflammation with possible deleterious consequences for COPD patients.
Nucleic acid aptamers in diagnosis of colorectal cancer Biochimie (IF 3.188) Pub Date : 2018-09-19 Yaghoub Ahmadyousefi, Sara Malih, Younes Mirzaee, Massoud Saidijam
Thermodynamics of the fourU RNA thermal switch derived from molecular dynamics simulations and spectroscopic techniques Biochimie (IF 3.188) Pub Date : 2018-09-19 Filip Leonarski, Maciej Jasiński, Joanna Trylska
Insulinotropic activity of the host-defense peptide frenatin 2D: conformational, structure-function and mechanistic studies Biochimie (IF 3.188) Pub Date : 2018-09-19 Vishal Musale, Laure Guilhaudis, Yasser H.A. Abdel-Wahab, Peter R. Flatt, J. Michael Conlon
Of four naturally occurring frenatin peptides tested, frenatin 2D (DLLGTLGNLPLPFI.NH2) from Discoglossus sardus was the most potent and effective in producing concentration-dependent stimulation of insulin release from BRIN-BD11 rat clonal β-cells without displaying cytotoxicity. The peptide also stimulated insulin release from 1.1B4 human-derived clonal β-cells and isolated mouse islets and improved glucose tolerance concomitant with increased circulating insulin concentrations in mice following intraperitoneal administration. The insulinotropic activity of frenatin 2D was not associated with membrane depolarization or an increase in intracellular [Ca2+] but incubation of the peptide (1μM) with BRIN-BD11 cells produced a modest, but significant (P < 0.05), increase in cAMP production. Stimulation of insulin release was abolished in protein kinase A-downregulated cells but maintained in protein kinase C-downregulated cells. Circular dichroism studies showed that, in the presence of dodecylphosphocholine micelles, frenatin 2D exhibited a helical content of 35% and a turn content of 28%. Substitution of the Thr5, Asn8, Pro10, and Ile14 residues in frenatin-2D by Trp and interchange of Pro12 and Phe13 led to loss of insulinotropic activity but the [D1W] and [G7W] analogues were as potent and effective as the native peptide. Frenatin 2D (1μM) also stimulated proliferation of BRIN-BD11 cells and provided significant protection of the cells against cytokine-induced apoptosis. It is concluded that the insulinotropic activity of frenatin 2D is mediated predominantly, if not exclusively, by the KATP channel-independent pathway.
ARL3 subcellular localization and its suspected role in autophagy Biochimie (IF 3.188) Pub Date : 2018-09-15 Guanghong Luo, Yangyang Sun, Ruili Feng, Qinping Zhao TieqiaoWen
ADP-ribosylation factor-like3 (ARL3) is a member of the ADP-ribosylation factor family of GTP-binding proteins that plays important role in regulating Ciliary trafficking. It ubiquitously expressed in normal tissues and tumor cell lines. However, the location and function of ARL3 in organelles are rarely known. In this study, we explored ARL3 subcellular localization in an all-round way in HEK293T, Neuro-2A and U251 cells by density gradient centrifugation and immunofluorescence. The results showed that ARL3 is expressed in most of organelles, and an iodixonal step gradient was further confirmed that ARL3 is mainly localized to the mitochondria, endosomes, lysosomes, and proteasome. By molecular functional analysis, we observed that ARL3 promotes the aggregation of GFP-LC3, up-regulation of LC3-II/LC3-I and down-regulation of SQSMT1/BECN1, and knocking down of ARL3 inbibits autophagy, which suggested that ARL3 is necessary for autophagy. this study presents a comprehensive evaluation of the subcellular localization for ARL3 and provides important on understanding the functions of ARL3.
Elucidating paramylon and other carbohydrate metabolism in Euglena gracilis: Kinetic characterization, structure and cellular localization of UDP-glucose pyrophosphorylase Biochimie (IF 3.188) Pub Date : 2018-09-15 Robertino J. Muchut, Rodrigo D. Calloni, Fernando E. Herrera, Sergio A. Garay, Diego G. Arias, Alberto A. Iglesias, Sergio A. Guerrero
Many oligo and polysaccharides (including paramylon) are critical in the Euglena gracilis life-cycle and they are synthesized by glycosyl transferases using UDP-glucose as a substrate. Herein, we report the molecular cloning of a gene putatively coding for a UDP-glucose pyrophosphorylase (EgrUDP-GlcPPase) in E. gracilis. After heterologous expression of the gene in Escherichia coli, the recombinant enzyme was characterized structural and functionally. Highly purified EgrUDP-GlcPPase exhibited a monomeric structure, able to catalyze synthesis of UDP-glucose with a Vmax of 3,350 U.mg-1. Glucose-1P and UTP were the preferred substrates, although the enzyme also used (with lower catalytic efficiency) TTP, galactose-1P and mannose-1P. Oxidation by hydrogen peroxide inactivated the enzyme, an effect reversed by reduction with dithiothreitol or thioredoxin. The redox process would involve sulfenic acid formation, since no pair of the 7 cysteine residues is close enough in the 3D structure of the protein to form a disulfide bridge. Electrophoresis studies suggest that, after oxidation, the enzyme arranges in many enzymatically inactive structural conformations; which were also detected in vivo. Finally, confocal fluorescence microscopy provided evidence for a cytosolic (mainly in the flagellum) localization of the enzyme.
Paeonol attenuates ligation-induced periodontitis in rats by inhibiting osteoclastogenesis via regulating Nrf2/NF-κB/NFATc1 signaling pathway Biochimie (IF 3.188) Pub Date : 2018-09-10 Ji Li, Yanping Li, Shuang Pan, Lin Zhang, Lina He, Yumei Niu
Paeonol is a natural phenolic compound in Moutan Cortex with multiple biological functions, such as anti-inflammatory and anti-oxidant activity. Recent evidence has proven that persistent inflammation, oxidative stress, along with nuclear factor E2-related factor 2 (Nrf2) signaling dysfunction in periodontium are the possible causes of alveolar bone resorption, and ultimately lead to periodontitis. The present study was designed to explore the protective effects of paeonol on ligation-induced periodontitis in rats, and investigate the possible mechanism. We found that treatment with paeonol (40, 80 mg/kg, intraperitoneal injection) for 7 days remarkably decreased the expression of receptor activator of nuclear factor kappa-B ligand increased the expression of osteoprotegrin and inhibited the formation of osteoclasts. This function of paeonol might be correlated with its ability to reduce inflammatory factors (IL-1β, IL-6 and TNF-α) and alleviate oxidative stress (SOD, MDA, GSH and ROS) in gingival tissues. Besides, paeonol increased Nrf2 activity. Silence of Nrf2 using specific siRNA diminished the inhibitory effect of paeonol on NF-κB p65 activation and aftedexpression, suggesting that Nrf2 was essential for protective effect of paeonol. These results showed that paeonol protected against periodontitis-aggravated osteoclastogenesis and alveolar bone lesion via regulating Nrf2/NF-κB/NFATc1 signaling pathway.
1-Naphthyl acetate: a chromogenic substrate for the detection of erythrocyte acetylcholinesterase activity Biochimie (IF 3.188) Pub Date : 2018-09-07 Sheemona Chowdhary, Rajasri Bhattacharyya, Dibyajyoti Banerjee
Erythrocyte acetylcholinesterase (AChE) is a preferred biomarker for the detection of organophosphorus poisoning. Acetylthiocholine (ATCh) is the most popular substrate for the detection of AChE activity. However, oximolysis is a prominent feature with ATCh. In this context, we have searched alternative substrates for AChE using in silico tools for screening of a better substrate. The in silico approach was performed to understand the fitness and the Total Interaction Energy (TIE) of substrates for AChE. The alternative substrates for AChE were screened in terms of high Goldscore and favorable TIE in comparison to acetylcholine (ACh)-AChE complex and other relevant esterases. Among the screened substrates, 1-Naphthyl acetate (1-NA) exhibited the most favorable interaction with AChE in terms of highest TIE and corresponding high Goldscore. The Molecular Dynamic (MD) simulation of the 1-NA-AChE complex showed a stable complex formation over a period of 5 ns. The results obtained in the in silico studies were validated in vitro using pure erythrocyte AChE and hemolysate. We observed 1-NA to be a better alternative substrate for AChE than ATCh in terms of lower Km value. Its specificity appeared at least similar to ATCh. Therefore, we propose that 1-NA can be an attractive chromogenic substrate for the measurement of AChE activity, and it possess the potential to detect organophosphorus pesticide (OP) poisoning.
Structure basis of the improved sweetness and thermostability of a unique double-sites single-chain sweet-tasting protein monellin (MNEI) mutant Biochimie (IF 3.188) Pub Date : 2018-09-06 Meng Zhao, Xiangqun Xu, Bo Liu
The sweet protein monellin has an intensely sweet potency but limited stability. We have identified a double-sites mutant (E2N/E23A) of the single-chain monellin (MNEI) with both improved sweetness (about 3-fold) and thermostability (10 °C). However, the structural basis of its superior properties remains elusive until now. Herein we report its crystal structure at a resolution 1.90 Å. Similar to the wild-type, E2N/E23A adopts a wedge-shaped structure consisting of a five-strand β-sheet partially “wrapped” around an α-helix. However, distinguishing parts were present in the loops region, including a remarkable conformation shift from β-strand to loop around residue R39. Molecular docking revealed the persistence of conserved protein-receptor interface and formation of new intermolecular ionic bonds in the E2N/E23A-receptor complex involving the taste-active residue R39 of the sweet protein, which could account for its significant improvement of sweetness. On the other hand, a rearrangement of intramolecular interaction network including the C-H … π bond between A23 and F89 that led to enhanced hydrophobicity in the protein core, could be correlated with its improved thermostability. Furthermore, two new sweeter mutants of MNEI were created. These findings highlight the critical roles of key sweetness determinant residue R39 and hydrophobicity at the protein core for the sweetness and thermostability of the protein, respectively, which thus provide a deeper insight for understanding the structure-function relationship of the sweet protein as well as guidance for rational design of this unique biomacromolecule.
Identification of a novel member of 2H phosphoesterases, 2ʹ,5ʹ-oligoadenylate degrading ribonuclease from the oyster Crassostrea gigas Biochimie (IF 3.188) Pub Date : 2018-09-05 Annika Lopp, Tõnu Reintamm, Anne Kuusksalu, Allan Olspert, Merike Kelve
Several genes of IFN-mediated pathways in vertebrates, among them the genes that participate in the 2ʹ,5ʹ-oligoadenylate synthetase (OAS)/RNase L pathway, have been identified in C. gigas. In the present study, we identified genes, which encode proteins having 2ʹ,5ʹ-oligoadenylate degrading activity in C. gigas. These proteins belong to the 2H phosphoesterase superfamily and have sequence similarity to the mammalian A kinase anchoring protein 7 (AKAP7) central domain, which is responsible for the 2ʹ,5ʹ-phosphodiesterase (2ʹ,5ʹ-PDE) activity. Comparison of the genomic structures of C. gigas proteins with that of AKAP7 suggests that these enzymes originate from a direct common ancestor. However, the identified nucleases are not typical 2ʹ,5ʹ-PDEs. The found enzymes catalyse the degradation of 2ʹ,5ʹ-linked oligoadenylates in a metal-ion-independent way, yielding products with 2ʹ,3ʹ -cyclic phosphate and 5ʹ-OH termini similarly to the 3ʹ−5ʹ bond cleavage in RNA, catalyzed by metal-independent ribonucleases. 3ʹ,5ʹ-linked oligoadenylates are not substrates for them. The preferred substrates for the C. gigas enzymes are 5ʹ-triphosphorylated 2ʹ,5ʹ-oligoadenylates, whose major cleavage reaction results in the removal of the 5ʹ-triphosphorylated 2ʹ,3ʹ-cyclic phosphate derivative, leaving behind the respective unphosphorylated 2ʹ,5ʹ-oligoadenylate. Such a cleavage reaction results in the direct inactivation of the biologically active 2-5A molecule. The 2ʹ,5ʹ-ribonucleases (2ʹ,5ʹ-RNases) from C. gigas could be members of the ancient group of ribonucleases, specific to 2ʹ−5ʹ phosphodiester bond, together with the enzyme that was characterized previously from the marine sponge Tethya aurantium. The novel 2ʹ,5ʹ-RNases may play a role in the control of cellular 2-5A levels, thereby limiting damage to host cells after viral infection.
SELEX methods on the road to protein targeting with nucleic acid aptamers Biochimie (IF 3.188) Pub Date : 2018-09-05 Payam Bayat, Rahim Nosrati, Mona Alibolandi, Houshang Rafatpanah, Khalil Abnous, Mostafa Khedri, Mohammad Ramezani
Biological relevance of double lipoxygenase products of polyunsaturated fatty acids, especially within blood vessels and brain Biochimie (IF 3.188) Pub Date : 2018-09-01 M. Guichardant, E. Véricel, M. Lagarde
The double lipoxygenation of polyunsaturated fatty acids (PUFA) is possible with PUFA having at least three methylene-interrupted double bonds. Several PUFA of the omega-3/n-3 and -6 families may be converted through this route, and the products show interesting inhibitory effects on blood platelet function and cyclooxygenase activities. This review focuses on two main omega-3 PUFA of nutritional interest, namely docosahexaenoic acid (DHA/22:6n-3) and alpha linolenic acid (ALA/18:3n-3). The chemical configuration of the double lipoxygenase end-product from DHA (protectin DX) is compared with that of protectin D1 which is produced through a mono-lipoxygenation step followed by an epoxidation and epoxide hydrolysis process. The different metabolic pathways are discussed as well as the different biological activities of both protectins.
ZNF224 is a transcriptional repressor of AXL in chronic myeloid leukemia cells Biochimie (IF 3.188) Pub Date : 2018-08-31 Gaetano Sodaro, Giancarlo Blasio, Federica Fiorentino, Patrick Auberger, Paola Costanzo, Elena Cesaro
ZNF224 is a KRAB-zinc finger transcription factor that exerts a key tumor suppressive role in chronic myelogenous leukemia.In this study, we identify the receptor tyrosine kinase Axl as a novel target of ZNF224 transcriptional repression activity. Axl overexpression is found in many types of cancer and is frequently associated with drug resistance. Interestingly, we also found that sensitivity to imatinib can be partly restored in imatinib-resistant chronic myelogenous leukemia cells by ZNF224 overexpression and the resulting suppression of Axl expression.These results, in accordance with our previous findings, support the role of ZNF224 in imatinib responsiveness and shed new insights into potential therapeutic use of ZNF224 in imatinib-resistant chronic myelogenous leukemia.
Photoactivable DNA probes to trap single-stranded DNA binding proteins: updating the potential of 4-thiothymidine from a comparative study Biochimie (IF 3.188) Pub Date : 2018-08-29 Tom Gérard-Hirne, Frédéric Thiebaut, Emmanuelle Sachon, Alexandre Désert, Thierry Drujon, Vincent Guérineau, Benoît Michel, Rachid Benhida, Stéphane Coulon, Carole Saintomé, Dominique Guianvarc'h
miR-487a promotes progression of gastric cancer by targeting TIA1 Biochimie (IF 3.188) Pub Date : 2018-08-23 Xuefeng Yang, Mingda Wang, Bohao Lin, Dongjie Yao, Jin Li, Xianchun Tang, Sanhua Li, Yun Liu, Rui Xie, Shouyang Yu
Gastric cancer (GC) is one of the most common malignancies as well as the third leading cause for cancer-related death. Molecular basis of GC are essential and critical for its therapeutic treatment, but still remain poorly understood. T-cell intracellular antigen-1 (TIA1) extensively involves in cancer progression, whereas its role and regulation mechanism in GC have not been revealed. In the present study, we found that TIA-1 protein level was down-regulated in GC tissues and TIA1 inhibited proliferation and promoted apoptosis of GC cells. Then, we used bioinformatics to predict miR-487a as the upstream regulator of TIA1 and we also observed an inverse correlation between miR-487a level and TIA-1 protein level in GC tissues. Next, we demonstrated that miR-487a directly targeted TIA1 via binding to its 3′-untranslated region. Furthermore, we investigated the role of miR-487a-TIA1 pathway in the growth of GC cells both in vitro and in vivo. The repression of TIA-1 by miR-487a promoted cell proliferation and suppressed cell apoptosis in vitro, and the knockdown of miR-487a had the opposite effects. Finally, we demonstrated that miR-487a promoted the development of gastric tumor growth in xenograft mice by targeting TIA-1. These effects could be partially reversed by restoring the expression of TIA-1. Overall, our results reveal that TIA1 is a tumor suppressor gene and is directly regulated by miR-487a in GC, which may offer new therapeutic targets for GC treatment.
Ablation of DJ-1 impairs brown fat function in diet-induced obese mice Biochimie (IF 3.188) Pub Date : 2018-08-22 Allwin Jennifa Silvester, Kanikkai Raja Aseer, Jong Won Yun
CYP46A1 protects against NMDA-mediated excitotoxicity in Huntington's disease: analysis of lipid raft content Biochimie (IF 3.188) Pub Date : 2018-08-11 Lydie Boussicault, Radhia Kacher, Antonin Lamazière, Peter Vanhoutte, Jocelyne Caboche, Sandrine Betuing, Marie-Claude Potier
Huntington's Disease (HD) is an autosomal dominant neurodegenerative disease caused by abnormal polyglutamine expansion in huntingtin (mHtt) protein leading to degeneration of striatal neurons. Excitotoxicity, consecutive to overstimulation of N-methyl D-aspartate receptors (NMDARs) has a pivotal role in many neurological disorders including HD. Mutant Htt causes enhanced NMDA sensitivity, alteration of NMDAR expression and localization in neurons. Excitotoxic events initiate neuronal death in numerous ways, including activation of apoptotic cascades. Among the NMDAR subunits involved in glutamatergic-mediated excitotoxicity, GluN2B has been extensively reported. In addition to excitotoxicity, alteration of cholesterol metabolism has been observed in HD, with a decrease of cholesterol precursor synthesis along with an increase of cholesterol accumulation, which is deleterious for neurons. Expression of Cholesterol Hydroxylase enzyme, CYP46A1, which converts cholesterol into 24 S‐hydroxycholesterol is down-regulated in HD. We found that CYP46A1 overexpression is beneficial in HD neurons and mouse model, but the mechanisms involved still remain unclear. In this study we addressed the effect of CYP46A1 on NMDAR-mediated excitotoxicity in HD primary neurons and its role in modulating cholesterol and localization of GLUN2B in lipid rafts. We showed that CYP46A1 is protective against NMDAR-mediated excitotoxicity in two different HD neuronal cell models. Cholesterol as well as GluN2B level in lipid raft, are significantly increased by mHtt. Despite a clear effect of CYP46A1 in reducing cholesterol content in lipid raft extracts from wild type neurons, CYP46A1 overexpression in HD neurons could not normalize the increased cholesterol levels in lipid rafts. This study highlights the beneficial role of CYP46A1 against NMDAR-mediated excitotoxicity and gives further insights into the cellular mechanisms underlying CYP46A1-mediated neuroprotection.
Exploring receptor selectivity of the chimeric relaxin family peptide R3/I5 by incorporating unnatural amino acids Biochimie (IF 3.188) Pub Date : 2018-08-10 Jia-Hui Wang, Meng-Jun Hu, Lei Zhang, Xiao-Xia Shao, Cai-Hong Lv, Ya-Li Liu, Zeng-Guang Xu, Zhan-Yun Guo
Relaxin family peptides perform a variety of biological functions by activating four G protein-coupled receptors, namely RXFP1−4. Our recent study demonstrated that selectivity of the chimeric relaxin family peptide R3/I5 towards the homologous RXFP3 and RXFP4 can be modulated by replacement of the highly conserved nonchiral B23Gly or B24Gly with some natural L-amino acids. To investigate the mechanism of this modulating effect, in the present study we incorporated unnatural amino acids into the B23 or B24 position of a semi-synthetic R3/I5 that was prepared by a novel sortase-catalysed ligation approach using synthetic relaxin-3 B-chain and recombinant INSL5 A-chain. R3/I5 was a weak agonist for RXFP3 after B23Gly was replaced by D-Ala or D-Ser, but a strong antagonist for this receptor after B23Gly was replaced by corresponding L-amino acids. However, these replacements always resulted in a weak agonist for RXFP4. Thus, configuration of the B23 residue of R3/I5 affected activation of RXFP3 but not RXFP4. For the B24 residue, both size and configuration affected receptor selectivity of R3/I5. L-amino acids with an appropriate size, such as L-Ser and L-Abu, had the greatest effect on increasing the selectivity of R3/I5 towards RXFP3 over the homologous RXFP4. Our present results provided new insights into receptor selectivity of R3/I5, and would facilitate design of novel agonists or antagonists for RXFP3 and RXFP4 in future studies.
A chronic LPS-induced low-grade inflammation fails to reproduce in lean mice the impairment of preference for oily solution found in diet-induced obese mice Biochimie (IF 3.188) Pub Date : 2018-08-10 Arnaud Bernard, Déborah Ancel, Patricia Passilly-Degrace, Jean-François Landrier, Laurent Lagrost, Philippe Besnard
Diet-induced obesity (DIO) is associated with a decreased oral fat detection in rodents. This alteration has been explained by an impairment of the lipid-mediated signaling in taste bud cells (TBC). However, factors responsible for this defect remain elusive. Diet rich in saturated fatty acids is known to elicit a metabolic inflammation by promoting intestinal permeation to lipopolysaccharides (LPS), Gram-negative bacteria-derived endotoxins. To determine whether a local inflammation of the gustatory tissue might explain the obese-induced impairment of the oro-sensory detection of lipids, mice were subjected to a DIO protocol. Using a combination of behavioral tests, transcriptomic analyses of gustatory papillae and biochemical assays, we have found that i) DIO elicits a pro-inflammatory genic profile in the circumvallate papillae (CVP), known to house the highest density of lingual taste buds, ii) NFkB, a key player of inflammatory process, might play a role in this transcriptomic pattern, iii) plasma LPS levels are negatively correlated with the preference for oily solution, and iv) a chronic infusion of LPS at a level similar to that found in DIO mice is not sufficient to alter the spontaneous preference for fat in lean mice. Taken together these data bring the demonstration that a saturated high fat diet elicits an inflammatory response at the level of peripheral gustatory pathway and a LPS-induced low-grade endotoxemia alone does not explain the change in the preference for dietary lipids observed in DIO mice.
Effect of a C-end rule Modification on Antitumor Activity of Thymosin α1 Biochimie (IF 3.188) Pub Date : 2018-08-08 Fanwen Wang, Caoying Xu, Renhao Peng, Bin Li, Xutong Shen, Heng Zheng, Xingzhen Lao
Irradiation by γ-rays reduces the level of H3S10 phosphorylation and weakens the G2 phase-dependent interaction between H3S10 phosphorylation and γH2AX Biochimie (IF 3.188) Pub Date : 2018-08-08 Eva Bártová, Gabriela Lochmanová, Soňa Legartová, Jana Suchánková, Radek Fedr, Jana Krejčí, Zbyněk Zdráhal
Potential Effects of Metformin in DNA BER System Based On Oxidative Status in Type 2 Diabetes Biochimie (IF 3.188) Pub Date : 2018-08-08 Irem Dogan Turacli, Tuba Candar, Emine Berrin YUKSEL, Sebnem Kalay, Ali Kemal OGUZ, Selda Demirtas
Metformin is used to reduce hyperglycemia that induces energetic stress and leads to reduction in gluconeogenesis. Also, metformin inhibits complex I in oxidative phosphorylation, thereby decreasing cellular ATP levels. Activation of AMPK by the reduced ATP levels can induce inhibition of reactive oxygen species (ROS) production and activate p53-mediated DNA repair. DNA polymerase-β and XRCC1 function to repair DNA damages in the BER (base excision repair) system. In type 2 diabetes patients, metformin can enhance AMPK activation therefore suppress oxidative stress. The changes on oxidative stress may alter p53's function and effect many cellular pathways such as; DNA repair. In our project we aim to understand the effects of metformin on p53 and DNA-BER system based on the oxidative status in type 2 diabetes patients. Oxidative and antioxidative capacity, catalase, SOD, GPx activities and, DNA pol beta, XRCC1 and p53 levels were measured in metformin using or non-using type 2 diabetes patients and controls. Metformin enhanced SOD and GPx activities in type 2 diabetes patients but the reflection of this increase to the total antioxidant capacity was not significant. Although the increase in DNA pol beta was not significant, XRCC1 and p53 levels were significantly upregulated with metformin treatment in type 2 diabetes patients. Our study reinforces the potential benefit of metformin in antioxidative capacity to protect cells from diabetic oxidative stress and in regulation of DNA BER system.
N-terminal phosphorylation of glutaminase C decreases its enzymatic activity and cancer cell migration Biochimie (IF 3.188) Pub Date : 2018-08-06 Carolline Fernanda Rodrigues Ascenção, Raghavendra Sashi Krishna Nagampalli, Zeyaul Islam, Matheus Pinto Pinheiro, Larissa Menezes dos Reis, Bianca Alves Pauletti, Carolina Aparecida de Guzzi Cassago, Daniela Campos Granato, Adriana Franco Paes Leme, Sandra Martha Gomes Dias
The multifaceted functions of lipopolysaccharide in plant-bacteria interactions Biochimie (IF 3.188) Pub Date : 2018-08-02 Alexander Kutschera, Stefanie Ranf
In Gram-negative bacteria, the cell envelope largely consists of lipopolysaccharide (LPS), a class of heterogeneous glycolipids. As a fundamental component of the outer membrane, LPS provides stability to the bacterial cell and forms a protective cover shielding it from hostile environments. LPS is not only fundamental to bacterial viability, but also makes a substantial contribution both directly and indirectly to multiple aspects of inter-organismic interactions. During infection of animal and plant hosts, LPS promotes bacterial virulence but simultaneously betrays bacteria to the host immune system. Moreover, dynamic remodulation of LPS structures allows bacteria to fine-tune OM properties and quickly adapt to diverse and often hostile environments, such as those encountered in host tissues. Here, we summarize recent insights into the multiple functions of LPS in plant-bacteria interactions and discuss what we can learn from the latest advances in the field of animal immunity. We further pinpoint open questions and future challenges to unravel the different roles of LPS in the dynamic interplay between bacteria and plant hosts at the mechanistic level.
The effect of electronic-cigarettes aerosol on rat brain lipid profile Biochimie (IF 3.188) Pub Date : 2018-08-02 Vladimiro Cardenia, Fabio Vivarelli, Silvia Cirillo, Moreno Paolini, Donatella Canistro, Maria Teresa Rodriguez-Estrada
Exploiting the impact of the secretome of MSCs isolated from different tissue sources on neuronal differentiation and axonal growth Biochimie (IF 3.188) Pub Date : 2018-08-02 Rita C. Assunção-Silva, B. Mendes-Pinheiro, P. Patrício, L. Behie, F.G. Teixeira, L. Pinto, A.J. Salgado
Cell transplantation free-based therapies using Mesenchymal stem cell (MSC) secretome have recently been presented as a possible for CNS related disorders. MSC secretome is rich in several bio-factors that act synergically towards the repair of damaged tissues, thus making it an ideal candidate for regenerative applications. Great effort is currently being made to map the molecules that compose the MSC secretome. Previous proteomic characterization of the secretome (in the form of conditioned media - CM) of MSCs derived from adipose tissue (ASC), bone-marrow (BMSC) and umbilical cord (HUCPVC) was performed by our group, where proteins relevant for neuroprotection, neurogenic, neurodifferentiation, axon guidance and growth functions were identified. Moreover, we have found significant differences among the expression of several molecules, which may indicate that their therapeutic outcome might be distinct. Having this in mind, in the present study, the neuroregulatory potential of ASC, BMSC and HUCPVC CM in promoting neurodifferentiation and axonal outgrowth was tested in vitro, using human telencephalon neuroprogenitor cells and dorsal root ganglion explants, respectively. The CM from the three MSC populations induced neuronal differentiation from human neural progenitor cells, as well as neurite outgrowth from dorsal root ganglion explants. Moreover, all the MSC populations promoted the same extent of neurodifferentiation, while ASC CM demonstrated higher potential in promoting axonal growth.
Serotonin in stem cell based-dental repair and bone formation: a review Biochimie (IF 3.188) Pub Date : 2018-08-02 Anne Baudry, Benoit Schneider, Jean-Marie Launay, Odile Kellermann
Genetic and pharmacological studies provided evidence that serotonin (5-HT) is an important signaling molecule for the development and the maintenance of mineralized tissues. However, how 5-HT takes part to the homeostasis of teeth and bone remains elusive. In the dental field, a major breakthrough comes from the identification of 5-HT but also dopamine (DA) as "damage" signals necessary for stem cell-based tooth repair. Pulpal stem cells express the overall functions of 5-HT and DA neurons including a definite set of functional 5-HT/DA receptors that render cells responsive for circulating bioamines. Upon tooth injury, activated platelets release bulks of 5-HT/DA that mobilize pulpal stem cells for natural dental repair. The contribution of 5-HT to bone metabolism is more documented with description of both anabolic and resorptive effects. By controlling the tissue-non specific alkaline phosphatase (TNAP), 5-HT2B receptors exert an anabolic function and a pivotal role in mineralization processes. Increasing our understanding of the role of 5-HT receptors in bone metabolism may pave the road for the development of therapeutic strategies towards skeletal-associated pathologies and ectopic calcification.
FOXD3 acts as a repressor of the mitochondrial S-adenosylmethionine carrier (SLC25A26) gene expression in cancer cells Biochimie (IF 3.188) Pub Date : 2018-08-02 Cianciulli Antonia, Menga Alessio, Palmieri Ferdinando, Iacobazzi Vito
The mitochondrial S-adenosylmethionine carrier (SAMC), encoded by the SLC25A26 gene, catalyzes the uptake of S-adenosylmethionine (SAM) from the cytosol into mitochondria in exchange for S-adenosylhomocysteine (SAH), produced inside the mitochondria. In the last years we have been functionally characterizing the promoter of SLC25A26 gene. In this study we show that a silencer activity is present in the region from -756 bp to -504 bp, which specifically binds a protein present in Caski cells nuclear extracts. By in silico analysis, EMSA, ChIP, overexpressing and silencing experiments this protein was identified as FOXD3 which acts as a repressor of SLC25A26 expression. Interestingly, the repressor activity of FOXD3 is completely abolished by treating Caski cells with folate via a mechanism that involves methylation of FOXD3 gene promoter. This finding could have important impact in cancer cells where SLC25A26 is downregulated. Finally, the DPE and INR putative sites were also identified.
Cysteine mediated disulfide bond formation in RAGE V domain facilitates its functionally relevant dimerization Biochimie (IF 3.188) Pub Date : 2018-08-01 Nitish Jangde, Rashmi Ray, Sunita Sinha, Khokan Rana, Satyendra Kumar Singh, Prashant Khandagale, Narottam Acharya, Vivek Rai
MiR-590-3p Inhibits Proliferation and Promotes Apoptosis by Targeting Activating Transcription Factor 3 in Human Breast Cancer Cells Biochimie (IF 3.188) Pub Date : 2018-08-01 M. Rohini, M. Gokulnath, P.J. Miranda, N. Selvamurugan
We previously reported that ATF3 and Runx2 are involved in breast cancer progression and bone metastasis. The expression of these genes can be controlled by post-transcriptional regulators such as microRNAs (miRNAs). In this study, we identified and validated the functional role of miR-590-3p in human breast cancer cells (MDA-MB231). There was an inverse correlation between the expression of miR-590-3p and its putative target genes, ATF3 and Runx2 in these cells. Overexpression of miR-590-3p decreased the expression of ATF3 and Runx2 at the mRNA and protein levels in MDA-MB231 cells. Luciferase reporter assay identified a direct interaction of 3’ UTRs of ATF3 and Runx2 with miR-590-3p in these cells. Overexpression of miR-590-3p also decreased proliferation and increased apoptosis of breast cancer cells. Based on our results, we suggest that miR-590-3p might have potential clinical applications towards controlling breast cancer progression and bone metastasis.
Sphingolipid metabolism in non-alcoholic fatty liver diseases Biochimie (IF 3.188) Pub Date : 2018-07-31 Marion Régnier, Arnaud Polizzi, Hervé Guillou, Nicolas Loiseau
Non-alcoholic fatty liver disease (NAFLD) involves a panel of pathologies starting with hepatic steatosis and continuing to irreversible and serious conditions like steatohepatitis (NASH) and hepatocarcinoma. NAFLD is multifactorial in origin and corresponds to abnormal fat deposition in liver. Even if triglycerides are mostly associated with these pathologies, other lipid moieties seem to be involved in the development and severity of NAFLD. That is the case with sphingolipids and more particularly ceramides. In this review, we explore the relationship between NAFLD and sphingolipid metabolism. After providing an analysis of complex sphingolipid metabolism, we focus on the potential involvement of sphingolipids in the different pathologies associated with NAFLD. An unbalanced ratio between ceramides and terminal metabolic products in the liver and plasma promotes weight gain, inflammation, and insulin resistance. In the etiology of NAFLD, some sphingolipid species such as ceramides may be potential biomarkers for NAFLD. We review the clinical relevance of sphingolipids in liver diseases.
Structure of the monotopic membrane protein (S)-mandelate dehydrogenase at 2.2Å resolution Biochimie (IF 3.188) Pub Date : 2018-07-30 N. Sukumar, S. Liu, W. Li, F.S. Mathews, B. Mitra, P. Kandavelu
The mycosporine-like amino acids porphyra-334 and shinorine are antioxidants and direct antagonists of Keap1-Nrf2 binding Biochimie (IF 3.188) Pub Date : 2018-07-30 Ranko Gacesa, Karl P. Lawrence, Nikolaos D. Georgakopoulos, Kazuo Yabe, Walter C. Dunlap, David J. Barlow, Geoffrey Wells, Antony R. Young, Paul F. Long
International descriptive and interventional survey for oxycholesterol determination by gas- and liquid-chromatographic methods Biochimie (IF 3.188) Pub Date : 2018-07-29 Dieter Lütjohann, Ingemar Björkhem, Silvia Friedrichs, Anja Kerksiek, Wolf-Jochen Geilenkeuser, Anita Lövgren-Sandblom, Diana Ansorena, Iciar Astiasarán, Lucia Baila-Rueda, Blanca Barriuso, Lionell Bretillon, Richard W. Browne, Claudio Caccia, Ana Cenarro, Peter J. Crick, Günter Fauler, Guadalupe Garcia-LLatas, William J. Griffiths, Hans-Frieder Schött
Increasing numbers of laboratories develop new methods based on gas-liquid and high-performance liquid chromatography to determine serum concentrations of oxygenated cholesterol metabolites such as 7α-, 24(S)-, and 27-hydroxycholesterol. We initiated a first international descriptive oxycholesterol (OCS) survey in 2013 and a second interventional survey 2014 in order to compare levels of OCS reported by different laboratories and to define possible sources of analytical errors. In 2013 a set of two lyophilized serum pools (A and B) was sent to nine laboratories in different countries for OCS measurement utilizing their own standard stock solutions. In 2014 eleven laboratories were requested to determine OCS concentrations in lyophilized pooled sera (C and D) utilizing the same provided standard stock solutions of OCS. The participating laboratories submitted results obtained after capillary gas-liquid chromatography-mass selective detection with either epicoprostanol or deuterium labelled sterols as internal standards and high-performance liquid chromatography with mass selective detection and deuterated OCS as internal standard. Each participant received a clear overview of the results in form of Youden-Plots and basic statistical evaluation in its used unit. The coefficients of variation of the concentrations obtained by all laboratories using their individual methods were 58.5–73.3% (survey 1), 56.8–60.3% (survey 2); 36.2–35.8% (survey 1), 56.6–59.8, (survey 2); 61.1–197.7% (survey 1), 47.2–74.2% (survey 2) for 24(S)-, 27-, and 7α-hydroxycholesterol, respectively. We are surprised by the very great differences between the laboratories, even under conditions when the same standards were used. The values of OCS's must be evaluated in relation to the analytical technique used, the efficiency of the ample separation and the nature of the internal standard used. Quantification of the calibration solution and inappropriate internal standards could be identified as major causes for the high variance in the reported results from the different laboratories. A harmonisation of analytical standard methods is highly needed.
Variability in lung cancer response to ALK inhibitors cannot be explained by the diversity of ALK fusion variants Biochimie (IF 3.188) Pub Date : 2018-07-30 Natalia V. Mitiushkina, Vladislav I. Tiurin, Aglaya G. Iyevleva, Maxim M. Kholmatov, Elena A. Filippova, Fedor V. Moiseyenko, Nikita E. Levchenko, Ivan S. Sardaryan, Svetlana V. Odintsova, Alexandra M. Lozhkina, Nikita M. Volkov, Nina A. Karaseva, Vladimir M. Moiseyenko, Sergey V. Orlov, Evgeny N. Imyanitov
Multiple laboratory evidences indicate that distinct variants of ALK translocations differ in their biochemical properties and responsiveness to ALK tyrosine kinase inhibitors (TKIs). These data are supported by some clinical studies, which showed improved responses to crizotinib in non-small cell lung cancer (NSCLC) patients carrying particular variants of ALK translocation. We retrospectively considered 64 Russian patients with ALK-rearranged NSCLC, who were treated by crizotinib (n = 23), ceritinib (n = 39) or alectinib (n = 2). ALK fusion variants were genotyped by PCR. Median progression-free survival (PFS) approached to 18 and 21 months in subjects with “short” (v.3a/b, v.5a/b) vs. “long” (TAPE-domain containing) fusion variants (p = 0.783), respectively; similar data were obtained while comparing EML4/ALK variant 1 vs. other ALK translocations (19 and 21 months, respectively; p = 0.604). Objective response rates were also strikingly similar in the above groups (“short”: 88%, “long”: 77%, p = 0.479; variant 1: 76%, other translocations: 81%, p = 0.753). Furthermore, ALK variants did not influence the disease outcomes when patients treated by crizotinib and ceritinib were analyzed separately. Overall, PFS on ALK TKI did not depend on whether the drug was administered upfront or after chemotherapy. Ceritinib produced significantly longer PFS than crizotinib (p = 0.022). In conclusion, this study revealed that distinct ALK translocation variants render similar clinical responsiveness to ALK inhibitors.
S-allyl cysteine as potent anti-gout drug: Insight into the xanthine oxidase inhibition and anti-inflammatory activity Biochimie (IF 3.188) Pub Date : 2018-07-27 Johnson Preethi, Loganathan Chitra, Iruthayaraj Ancy, Poomani Kumaradhas, Thayumanavan Palvannan
S-allyl cysteine (SAC) is known for its various beneficial effects such as neuroprotection and immunomodulation. The beneficial effect of SAC against gout has not been explored. The present study aims to describe the two roles of SAC: (1) inhibitory effect against xanthine oxidase (XO) enzyme activity; and (2) anti-inflammatory property against MSU crystal-induced gouty inflammation in rat. The inhibitory effect of SAC against bovine XO enzyme activity was determined in vitro. In silico analysis was carried out to determine the intermolecular interaction between SAC and bovine XO. MSU crystal was injected in the right paw of the rat to induce gouty inflammation. SAC (40 mg/kg body weight) and colchicine (positive control; 1 mg/kg body weight) was given for 3 days. At the end of the treatment, the oxidative stress, antioxidant parameters and mitochondrial function were determined in the ankle joint tissue. The concentration of inflammatory cytokines such as TNF-α and IL-1β was measured in the serum using ELISA. SAC inhibited (IC50 value, 33 μg/ml) XO enzyme activity in a competitive mode with corresponding Ki value of 4 μg/ml. In silico analysis predicted the interaction of SAC with the amino acids such as Arg880, Phe798, Phe914 and Phe1009 of XO enzyme. The root mean square deviation, root mean square fluctuation and free energy calculation values confirmed the stable SAC-XO interaction. The inhibition of SAC on XO enzyme activity in in vivo was further confirmed by silkworm model. SAC through reducing oxidative stress, enhancing antioxidants, protecting mitochondrial function has shown anti-inflammatory effect against MSU crystal-induced gout which was observed as reduced level of inflammatory markers in the serum. The medicinal potential of SAC as a preventive agent through its XO inhibitory property as well as curative agent through its anti-inflammatory property against gout has been understood from the present study.
A stochastic approach to serotonergic fibers in mental disorders Biochimie (IF 3.188) Pub Date : 2018-07-26 Skirmantas Janušonis, Nils Detering
Virtually all brain circuits are physically embedded in a three-dimensional matrix of fibers that release 5-hydroxytryptamine (5-HT, serotonin). The density of this matrix varies across brain regions and cortical laminae, and it is altered in some mental disorders, including Major Depressive Disorder and Autism Spectrum Disorder. We investigate how the regional structure of the serotonergic matrix depends on the stochastic behavior of individual serotonergic fibers and introduce a new framework for the quantitative analysis of this behavior. In particular, we show that a step-wise random walk, based on the von Mises-Fisher probability distribution, can provide a realistic and mathematically concise description of these fibers. We also consider other stochastic models, including the fractional Brownian motion. The proposed approach seeks to advance the current understanding of the ascending reticular activating system (ARAS) and may also support future theory-guided therapeutic approaches.
27-hydroxycholesterol decreases cell proliferation in colon cancer cell lines Biochimie (IF 3.188) Pub Date : 2018-07-24 Jessica Warns, Gurdeep Marwarha, Natalie Freking, Othman Ghribi
Colorectal cancer (CRC) is the third most diagnosed cancer in the western world, affecting 1 out of approximately 22 people in their lifetime. Several epidemiological studies suggest a positive association between high plasma cholesterol levels and colorectal cancer. However, the molecular mechanisms by which cholesterol may alter the risk of colorectal cancer (CRC) are ill-defined as the cholesterol lowering drugs statins do not appear to decrease a patient's risk of developing colorectal cancer. Cholesterol is metabolized to active derivatives including cholesterol oxidization products (COP), known as oxysterols, which have been shown to alter cellular proliferation. These metabolites and not cholesterol per se, may therefore affect the risk of developing colorectal cancer. The cholesterol metabolite or the oxysterol 27-hydroxycholesterol (27-OHC) is the most abundant oxysterol in the plasma and has been shown to be involved in the pathogenesis of several cancers including breast and prostate cancer. However, the role of 27-OHC in colorectal cancer has not been investigated. We treated Caco2 and SW620, two well characterized colon cancer cells with low, physiological and high concentrations of 27-OHC, and found that 27-OHC reduces cellular proliferation in these cells. We also found that the effects of 27-OHC on cell proliferation are not due to cellular cytotoxicity or apoptotic cellular death. Additionally, 27-OHC-induced reduction in cell proliferation is independent of actions on its target nuclear receptors, liver-X-receptors (LXR) and estrogen receptors (ER) activation. Instead, our study demonstrates that 27-OHC significantly decreases AKT activation, a major protein kinase involved in the pathogenesis of cancer as it regulates cell cycle progression, protein synthesis, and cellular survival. Our data shows that treatment with 27-OHC substantially decreases the activation of AKT by reducing levels of its active form, p-AKT, in Caco2 cells but not SW620 cells. All-together, our results show for the first time that the cholesterol metabolite 27-OHC reduces cell proliferation in colorectal cancer cells.
Biophysical Characterization of a Recombinant Lipase KV1 from Acinetobacter haemolyticus in Relation to pH and Temperature Biochimie (IF 3.188) Pub Date : 2018-07-20 Kalaivani Batumalaie, Elham Khalili, Naji Arafat Mahat, Fahrul Huyop, Roswanira Abdul Wahab
Spectroscopic and calorimetric methods were employed to assess the stability and the folding aspect of a novel recombinant alkaline-stable lipase KV1 from Acinetobacter haemolyticus under varying pH and temperature. Data on far ultraviolet-circular dichroism of recombinant lipase KV1 under two alkaline conditions (pH 8.0 and 12.0) at 40˚C reveal strong negative ellipticities at 208, 217, 222 nm, implying its secondary structure belonging to a α + β class with 47.3 and 39.0 % ellipticity, respectively. Results demonstrate that lipase KV1 adopts its most stable conformation at pH 8.0 and 40˚C. Conversely, the protein assumes a random coil structure at pH 4.0 and 80˚C, evident from a strong negative peak at ⁓ 200 nm. This blue shift suggests a general decline in enzyme activity in conjunction with the partially or fully unfolded state that invariably exposed more hydrophobic surfaces of the lipase protein. The maximum emission at ∼335 nm for pH 8.0 and 40˚C indicates the adoption of a favorable protein conformation with a high number of buried tryptophan residues, reducing solvent exposure. Appearance of an intense Amide I absorption band at pH 8.0 corroborates an intact secondary structure. A lower enthalpy value for pH 4.0 over pH 8.0 and 12.0 in the differential scanning calorimetric data corroborates the stability of the lipase at alkaline conditions, while a low Km (0.68 ± 0.03 mM) for tributyrin verifies the high affinity of lipase KV1 for the substrate. The data, herein offer useful insights into future structure-based tunable catalytic activity of lipase KV1.
Zinc(II) binding on human wild-type ISCU and Met140 variants modulates NFS1 desulfurase activity Biochimie (IF 3.188) Pub Date : 2018-07-20 Nicholas G. Fox, Alain Martelli, Joseph F. Nabhan, Jay Janz, Oktawia Borkowska, Christine Bulawa, Wyatt W. Yue
Human de novo iron-sulfur (Fe-S) assembly complex consists of cysteine desulfurase NFS1, accessory protein ISD11, acyl carrier protein ACP, scaffold protein ISCU, and allosteric activator frataxin (FXN). FXN binds the NFS1-ISD11-ACP-ISCU complex (SDAU), to activate the desulfurase activity and Fe-S cluster biosynthesis. In the absence of FXN, the NFS1-ISD11-ACP (SDA) complex was reportedly inhibited by binding of recombinant ISCU. Recent studies also reported a substitution at position Met141 on the yeast ISCU orthologue Isu, to Ile, Leu, Val, or Cys, could bypass the requirement of FXN for Fe-S cluster biosynthesis and cell viability. Here, we show that recombinant human ISCU binds zinc(II) ion, as previously demonstrated with the E. coli orthologue IscU. Surprisingly, the relative proportion between zinc-bound and zinc-depleted forms varies among purification batches. Importantly the presence of zinc in ISCU impacts SDAU desulfurase activity. Indeed, removal of zinc(II) ion from ISCU causes a moderate but significant increase in activity compared to SDA alone, and FXN can activate both zinc-depleted and zinc-bound forms of ISCU complexed to SDA. Taking into consideration the inhibition of desulfurase activity by zinc-bound ISCU, we characterized wild type ISCU and the M140I, M140L, and M140V variants under both zinc-bound and zinc-depleted conditions, and did not observe significant differences in the biochemical and biophysical properties between wild-type and variants. Importantly, in the absence of FXN, ISCU variants behaved like wild-type and did not stimulate the desulfurase activity of the SDA complex. This study therefore identifies an important regulatory role for zinc-bound ISCU in modulation of the human Fe-S assembly system in vitro and reports no ‘FXN bypass’ effect on mutations at position Met140 in human ISCU. Furthermore, this study also calls for caution in interpreting studies involving recombinant ISCU by taking into consideration the influence of the bound zinc(II) ion on SDAU complex activity
Cloning, purification and characterization of nigrelysin, a novel actinoporin from the sea anemone Anthopleura nigrescens Biochimie (IF 3.188) Pub Date : 2018-07-21 Javier Alvarado-Mesén, Frank Solano-Campos, Liem Canet, Lohans Pedrera, Yadira P. Hervis, Carmen Soto, Henry Borbón, María E. Lanio, Bruno Lomonte, Aisel Valle, Carlos Alvarez
Actinoporins constitute a unique class of pore-forming toxins found in sea anemones that being secreted as soluble monomers are able to bind and permeabilize membranes leading to cell death. The interest in these proteins has risen due to their high cytotoxicity that can be properly used to design immunotoxins against tumor cells and antigen-releasing systems to cell cytosol. In this work we describe a novel actinoporin produced by Anthopleura nigrescens, an anemone found in the Central American Pacific Ocean. Here we report the amino acid sequence of an actinoporin as deduced from cDNA obtained from total body RNA. The synthetic DNA sequence encoding for one cytolysin variant was expressed in BL21 Star (DE3) Escherichia coli and the protein purified by chromatography on CM Sephadex C-25 with more than 97% homogeneity as verified by MS-MS and HPLC analyses. This actinoporin comprises 179 amino acid residues, consistent with its observed isotope-averaged molecular mass of 19661 Da. The toxin lacks Cys and readily permeabilizes erythrocytes, as well as L1210 cells. CD spectroscopy revealed that its secondary structure is dominated by beta structure (58.5%) with 5.5% of α-helix, and 35% of random structure. Moreover, binding experiments to lipidic monolayers and to liposomes, as well as permeabilization studies in vesicles, revealed that the affinity of this toxin for sphingomyelin-containing membranes is quite similar to sticholysin II (StII). Comparison by spectroscopic techniques and modeling the three-dimensional structure of nigrelysin (Ng) showed a high homology with StII but several differences were also detectable. Taken together, these results reinforce the notion that Ng is a novel member of the actinoporin pore-forming toxin (PFT) family with a HA as high as that of StII, the most potent actinoporin so far described, but with peculiar structural characteristics contributing to expand the understanding of the structure-function relationship in this protein family.
The impact of Mesenchymal Stem Cells and their secretome as a treatment for gliomas Biochimie (IF 3.188) Pub Date : 2018-07-19 E.D. Gomes, J. Vieira de Castro, B.M. Costa, A.J. Salgado
In recent years, we have witnessed a significant increase in the amount of studies using Mesenchymal Stem Cells (MSCs) for cancer therapy, mostly as vectors for drug or gene delivery strategies. This is because of their intrinsic capacity of homing into tumor niches. However, the interactions between MSCs themselves and tumor cells is not fully understood, with contradictory results frequently being observed regarding their effects on cancer cell invasion and proliferation. This poses an important question of safety in respect to the application of these cells. The source of the MSC population used, as well as the type of cancer cells under study might strongly influence this interaction. Moreover, differences in isolation protocols, culture media compositions, time of culture and conditioned media collection, or even timing and mode of MSCs administration to in vivo models of cancer may also affect the interaction MSC-tumor cells. In this review, we drive our focus into malignant brain tumors, particularly gliomas, one of the deadliest forms of cancer. Moreover, we look with some detail into different studies using MSCs as a treatment for brain tumors and compare them, highlighting the main deviations and similarities among them.
Induction of peroxisomal changes in oligodendrocytes treated with 7-ketocholesterol: Attenuation by α-tocopherol Biochimie (IF 3.188) Pub Date : 2018-07-19 Thomas Nury, Randa Sghaier, Amira Zarrouk, Franck Ménétrier, Tugba Uzun, Valerio Leoni, Claudio Caccia, Wiem Meddeb, Amira Namsi, Khouloud Sassi, Wafa Mihoubi, Jean-Marc Riedinger, Mustapha Cherkaoui-Malki, Thibault Moreau, Anne Vejux, Gérard Lizard
The involvement of organelles in cell death is well established especially for endoplasmic reticulum, lysosomes and mitochondria. However, the role of the peroxisome is not well known, though peroxisomal dysfunction favors a rupture of redox equilibrium. To study the role of peroxisomes in cell death, 158 N murine oligodendrocytes were treated with 7-ketocholesterol (7 KC: 25–50 μM, 24 h). The highest concentration is known to induce oxiapoptophagy (OXIdative stress + APOPTOsis + autoPHAGY), whereas the lowest concentration does not induce cell death. In those conditions (with 7 KC: 50 μM) morphological, topographical and functional peroxisome alterations associated with modifications of the cytoplasmic distribution of mitochondria, with mitochondrial dysfunction (loss of transmembrane mitochondrial potential, decreased level of cardiolipins) and oxidative stress were observed: presence of peroxisomes with abnormal sizes and shapes similar to those observed in Zellweger fibroblasts, lower cellular level of ABCD3, used as a marker of peroxisomal mass, measured by flow cytometry, lower mRNA and protein levels (measured by RT-qPCR and western blotting) of ABCD1 and ABCD3 (two ATP-dependent peroxisomal transporters), and of ACOX1 and MFP2 enzymes, and lower mRNA level of DHAPAT, involved in peroxisomal β-oxidation and plasmalogen synthesis, respectively, and increased levels of very long chain fatty acids (VLCFA: C24:0, C24:1, C26:0 and C26:1, quantified by gas chromatography coupled with mass spectrometry) metabolized by peroxisomal β-oxidation. In the presence of 7 KC (25 μM), slight mitochondrial dysfunction and oxidative stress were found, and no induction of apoptosis was detected; however, modifications of the cytoplasmic distribution of mitochondria and clusters of mitochondria were detected. The peroxisomal alterations observed with 7 KC (25 μM) were similar to those with 7 KC (50 μM). In addition, data obtained by transmission electron microcopy and immunofluorescence microscopy by dual staining with antibodies raised against p62, involved in autophagy, and ABCD3, a peroxisomal ABC transporter, support that 7 KC (25–50 μM) induces pexophagy. 7 KC (25–50 μM)-induced side effects were attenuated by α-tocopherol but not by α-tocotrienol, whereas the anti-oxidant properties of these molecules determined with the FRAP assay were in the same range. These data provide evidences that 7 KC, at concentrations inducing or not cell death, triggers morphological, topographical and functional peroxisomal alterations associated with minor or major mitochondrial changes.
Gerli invited minireview Fatty acids and oxidized lipoproteins contribute to autophagy and innate immunity responses upon the degeneration of retinal pigment epithelium and development of age-related macular degeneration Biochimie (IF 3.188) Pub Date : 2018-07-18 Kai Kaarniranta, Ali Koskela, Szabolcs Felszeghy, Niko Kivinen, Antero Salminen, Anu Kauppinen
Retinal pigment epithelium (RPE) damage is a primary sign in the development of age-related macular degeneration (AMD) the leading cause of blindness in western countries. RPE cells are exposed to chronic oxidative stress due to constant light exposure, active fatty acid metabolism and high oxygen consumption. RPE cells phagocytosize lipid rich photoreceptor outer segment (POS) which is regulated by circadian rhytmn. Docosahexaenoic acid is present in high quantity in POS and increases oxidative stress, while its metabolites have cytoprotective effects in RPE. During RPE aging, reactive oxygen species and oxidized lipoproteins are considered to be major causes of disturbed autophagy clearance that lead to chronic innate immunity response involved in NOD-Like, Toll-Like, Advanced Glycation End product Receptors (NRLP, TLR, RAGE, respectively), pentraxins and complement systems. We discuss role of fatty acids and lipoproteins in the degeneration of RPE and development of AMD.
Dual mechanism of type VII collagen transfer by bone marrow mesenchymal stem cell extracellular vesicles to recessive dystrophic epidermolysis bullosa fibroblasts Biochimie (IF 3.188) Pub Date : 2018-04-10 Jeffrey D. McBride, Luis Rodriguez-Menocal, Ambar Candanedo, Wellington Guzman, Marta Garcia-Contreras, Evangelos V. Badiavas
Recessive dystrophic epidermolysis bullosa (RDEB) is a severe blistering disease resulting from a lack of type VII collagen production. Recent clinical trials have shown efficacy of bone marrow-derived mesenchymal stem cells (BM-MSCs) in the treatment of epidermolysis bullosa, including improved basement membrane restructuring and cutaneous wound healing. The mechanism as to how type VII collagen is transferred from donor stem cell to recipient RDEB cells has not been defined. Here, we submit the model that BM-MSC-derived extracellular vesicles serve at least two roles: 1) to help transport type VII collagen within the extracellular space; and 2) to feed RDEB fibroblasts with messenger RNA that codes for type VII collagen, resulting in COL7A1 translation and synthesis of type VII collagen alpha chain proteins by RDEB fibroblasts. Utilizing a chemoselective ligation detection method, we found RDEB cells that were treated simultaneously with BM-MSC EVs and an l-methionine analog, l-homopropargylglycine (HPG), synthesized collagen VII alpha chain protein that contained the alkyne group of HPG to react (i.e. undergo the Click-iT® reaction) with azide-modified Alexa 594, suggesting de novo synthesis of type VII collagen by RDEB fibroblasts. Thus, our results support a model in which BM-MSC EVs help increase type VII collagen levels available to recipient cells by 1) donating BM-MSC type VII collagen protein and 2) inducing RDEB fibroblasts to make their own type VII collagen protein. These findings allow us to hypothesize that the secretome of BM-MSCs could have therapeutic value in the treatment of RDEB-related skin disorders.
Chemistry, biochemistry, metabolic fate and mechanism of action of 6-oxo-cholestan-3β,5α-diol (OCDO), a tumor promoter and cholesterol metabolite Biochimie (IF 3.188) Pub Date : 2018-04-12 Marc Poirot, Regis Soules, Arnaud Mallinger, Florence Dalenc, Sandrine Silvente-Poirot
Oxygenation products of cholesterol, named oxysterols, were suspected since the 20th century to be involved in carcinogenesis. Among the family of oxysterol molecules, cholesterol-5,6-epoxides (5,6-EC) retained the attention of scientists because they contain a putative alkylating epoxide group. However, studies failed into demonstrating that 5,6-EC were direct carcinogens and revealed a surprising chemical stability and unreactivity towards nucleophiles in standard conditions. Analyses of 5,6-EC metabolism in normal cells showed that they were extensively transformed into cholestane-3β,5α,6β-triol (CT) by the cholesterol-5,6-epoxide hydrolase (ChEH). Studies performed in cancer cells showed that CT was additionally metabolized into an oxysterol identified as the 6-oxo-cholestan-3β,5α-diol (OCDO), by the 11β-hydroxysteroid dehydrogenase of type 2 (HSD2), the enzyme which inactivates cortisol into cortisone. Importantly, OCDO was shown to display tumor promoter properties in breast cancers, by binding to the glucocorticoid receptor, and independently of their estrogen receptor status, revealing the existence of a new tumorigenic pathway centered on 5,6-EC. In breast tumors from patients, OCDO production as well as the expression of the enzymes involved in the pathway producing OCDO, namely ChEH subunits and HSD2, were higher compared to normal tissues, and overexpression of these enzymes correlate with a higher risk of patient death, indicating that this onco-metabolism is of major importance to breast cancer pathology. Herein, we will review the actual knowledge and the future trends in OCDO chemistry, biochemistry, metabolism and mechanism of action and will discuss the impact of OCDO discovery on new anticancer therapeutic strategies.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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