Application of Nanotechnology to target and exploit tumour associated proteases Biochimie (IF 3.188) Pub Date : 2019-04-25 Francesco Cogo, Rich Williams, Roberta E. Burden, Christopher J. Scott
Proteases are hydrolytic enzymes fundamental for a variety of physiological processes, but the loss of their regulation leads to aberrant functions that promote onset and progression of many diseases including cancer. Proteases have been implicated in almost every hallmark of cancer and whilst widely investigated for tumour therapy, clinical adoption of protease drugs remains a challenge due to issues such as off-target toxicity and inability to achieve therapeutic doses at the disease site. Now, nanotechnology-based solutions and strategies are emerging to circumvent these issues. In this review, preclinical advances in approaches to enhance the delivery of protease drugs and the exploitation of tumour-derived protease activities to promote targeting of nanomedicine formulations is examined. Whilst this field is still in its infancy, innovations to date suggest that nanomedicine approaches to protease targeting or inhibition may hold much therapeutic and diagnostic potential.
Long non-coding RNA Linc00221 mediates cisplatin resistance in non-small-cell lung cancer (NSCLC) via sponging miR-519a Biochimie (IF 3.188) Pub Date : 2019-04-25 Huaping Tang, Xianzhang Han, Meng Li, Tingtian Li, Yueqin Hao
Cisplatin resistance has been long considered an obstacle to the efficacy of chemotherapy in non-small-cell lung cancer (NSCLC). Long non-coding RNAs (lncRNAs) have been widely reported to participate in the various biological process including cancer. In the present study, we aim to explore the functions of Linc00221 and miR-519a in the sensitivity and the resistance of NSCLC to cisplatin. The levels of Linc00221, miR-519a, and zinc finger and BTB domain-containing five (ZBTB5) in NSCLC tissues were detected by qRT-PCR and Western blot. Colony formation and MTT assays were applied to detect the viability of cells after cisplatin treatment. Dual luciferase reporter assays were used to detect the inhibitory effect of miR-519a on ZBTB5 and Linc00221, and pull down experiments were employed to determine the direct interaction between Linc00221 and miR-519a. Our results showed that Linc00221 was highly expressed in cisplatin-resistant NSCLC tissues and cells and closely associated with poor prognosis. Linc00221 promoted the cisplatin resistance of NSCLC and miR-519a was a direct target of Linc00221. In addition, miR-519a could promote cisplatin sensitivity in NSCLC cells by targeting ZBTB5. Linc00221 could mediate the cisplatin sensitivity in NSCLC by adsorbing miR-519a to prevent its down-regulation of ZBTB5. In conclusion, Linc00221 promotes cisplatin resistance in NSCLC through the downstream miR-519a/ZBTB5 signaling axis, which could be used as a potential diagnostic and therapeutic target for clinical cisplatin-resistant NSCLC patients.
Benzothiazole derivatives as fluorescent “light-up” probes for duplex and quadruplex DNA Biochimie (IF 3.188) Pub Date : 2019-04-22 Anton V. Turaev, Vladimir B. Tsvetkov, Maria V. Tankevich, Igor P. Smirnov, Andrey V. Aralov, Galina E. Pozmogova, Anna M. Varizhuk
Analogs of benzothiazole orange (BO) with one, two or three methylbenzothiazolylmethylidene substituents in the 1-methylpyridinium ring were obtained from the respective picolinium, lutidinium or collidinium salts. Fluorescence parameters of the known and new dyes in complexes with various DNA structures, including G-quadruplexes (G4s) and i-motifs (IMs), were analyzed. All dyes efficiently distinguished G4s and ss-DNA. The bi- and tri-substituted derivatives had basically similar distributions of relative fluorescence intensities. The mono-substituted derivatives exhibited enhanced sensitivity to parallel G4s. All dyes were particularly sensitive to a G4 structure with an additional duplex module (the thrombin-binding aptamer TBA31), presumably due to a distinct binding pattern (interaction with the junction between the two modules). In particular, BO showed a strong (170-fold) enhancement in fluorescence quantum yield in complex with TBA31 compared to the free dye. The fluorescence quantum yields of the bi-substituted derivative in complex with well-characterized G4s from oncogene promoters were comparable to those of ThT. The mono/bi-substituted derivatives should be considered as possible light-up probes for G4 formation.
Metabolic and physiological perturbations of Escherichia coli W3100 by bacterial small RNA RyhB Biochimie (IF 3.188) Pub Date : 2019-04-17 Yu Lv, Jihui Wu, Yunyu Shi
RyhB is a key regulator of iron level in Escherichia coli (E. coli), which assists in conserving iron for life-sustaining cellular functions when cytoplasmic levels of the ferrous form of iron is limited. RyhB affects glucose metabolism. Seventy percent of the genes that are regulated by RyhB are related to metabolism. We demonstrated for the first time that the activity of the pentose phosphate pathway increased upon ryhB activation using a 13C stable isotope-based technique called METAFoR (Metabolic flux ratio analysis). U-13C glucose-based studies showed that the reversible exchange activity of serine and glycine was enhanced by flux redistribution, which further favors NADPH formation. In addition, Entner–Doudoroff (ED) pathway activity was inhibited in the ryhB-defective cells. Quantitative physiology-based experiments highlighted a significant increase in the levels of reactive oxygen species (ROS) in ryhB-induced W3100 E. coli cells in batch culture. A simultaneous decrease in NADH/NAD+ and NADPH/NADP+ ratios outlined the potentially direct roles of NADH and NADPH in antagonizing the excess ROS formed after ryhB activation. Our observations offer a new perspective regarding the roles of RyhB and highlight that this small RNA can significantly affect cell metabolism in addition to its role as a regulator of gene expression.
TLR2 and TLR4 mediate an activation of adipose tissue renin-angiotensin system induced by uric acid Biochimie (IF 3.188) Pub Date : 2019-04-16 Junxia Zhang, Bo Diao, Xue lin, Jinxiu Xu, Feng Tang
Both hyperuricemia and adipose tissue renin–angiotensin system (RAS) are closely associated with multiple metabolic and cardiovascular diseases. We previously reported that uric acid could upregulate tissue RAS in adipocytes. In the present study, we aimed to reveal the involvement of toll-like receptors (TLRs) in uric acid-induced RAS activation in adipose tissue. A hyperuricemia rat model fed with a high-fructose diet and rat primary adipocytes were used in this study. Here, we inhibited TLR2 and TLR4 expression in adipose tissue and cultured adipocytes using small interfering RNA (siRNA). We found that high fructose-fed rats had hyperuricemia, higher body weight and greater adipose tissue content. We also found that hyperuricemia rats had raising blood pressure, higher expression levels of inflammatory cytokines and RAS components in adipose tissue, which could be prevented by TLR2/4-siRNA infection. In vitro study, uric acid caused a dose- and time-dependent increase in the mRNA expression of TLR2 and TLR4 in rat adipocytes. Uric acid could increase inflammatory cytokines and upregulate tissue RAS in rat adipocytes, which were both blocked with TLR2/4-siRNA infection. TNF-α and IL-6 could also result in an activation of tissue RAS expression in adipocytes. In conclusion, TLR2/4 mediated adipose inflammation plays a key role in RAS activation induced by uric acid in adipose tissue.
Up-regulation of microRNA-496 suppresses proliferation, invasion, migration and in vivo tumorigenicity of human osteosarcoma cells by targeting eIF4E Biochimie (IF 3.188) Pub Date : 2019-04-16 Ni-Nan Qi, Shuo Tian, Xin Li, Fu-Li Wang, Bin Liu
Osteosarcoma is an aggressive bone tumor characterized by a high level of genetic instability and recurring DNA deletions and amplifications. This study aims to investigate how microRNA-496 (miR-496) affects proliferation, invasion, and migration of human osteosarcoma (OS) cells and in vivo tumorigenicity by targeting eukaryotic translation initiation factor 4E (eIF4E). Microarray-based gene expression profiling involving OS was used in order to identify differentially expressed genes. After that, the interaction between miR-496 expression and OS patients’ survival rate was determined. The expression pattern of miR-496 and eIF4E was determined in OS tissues and cells, and their potential relationship was further analyzed by using the dual luciferase reporter gene assay. With the purpose of identifying the functional role miR-496 in OS, cell proliferation, migration, and invasion were measured in cells treated with miR-496 mimic or inhibitor. A nude mouse model was constructed in order to investigate the regulatory effects of miR-496 on tumor growth in vivo by regulating eIF4E. OS cells exhibited a down-regulated expression of miR-496 and an up-regulated expression of eIF4E. miR-496 expression was positively correlated to OS patients’ survival rate. Bioinformatics analysis suggested eIF4E would be a direct target of miR-496, and the expression of eIF4E was inhibited by overexpression of miR-496. miR-496 elevation was found to exert suppressive effects on OS cell proliferation, migration and invasion in vitro and tumor growth in vivo, with the effects being reversed using miR-496 depletion. Altogether, the above findings support a conclusion that miR-496 could work as a tumor suppressor in OS through down-regulation of eIF4E. This study may provide a novel target for treatment of OS.
Physiological roles of antisense RNAs in prokaryotes Biochimie (IF 3.188) Pub Date : 2019-04-14 Maxence Lejars, Asaki Kobayashi, Eliane Hajnsdorf
Prokaryotes encounter constant and often brutal modifications to their environment. In order to survive, they need to maintain fitness, which includes adapting their protein expression patterns. Many factors control gene expression but this review focuses on just one, namely antisense RNAs (asRNAs), a class of non-coding RNAs (ncRNAs) characterized by their location in cis and their perfect complementarity with their targets. asRNAs were considered for a long time to be trivial and only to be found on mobile genetic elements. However, recent advances in methodology have revealed that their abundance and potential activities have been underestimated. This review aims to illustrate the role of asRNA in various physiologically crucial functions in both archaea and bacteria, which can be regrouped in three categories: cell maintenance, horizontal gene transfer and virulence. A literature survey of asRNAs demonstrates the difficulties to characterize and assign a role to asRNAs. With the aim of facilitating this task, we describe recent technological advances that could be of interest to identify new asRNAs and to discover their function.
CREPT promotes glioma cell proliferation and invasion by activating Wnt/β-catenin pathway and is a novel target of microRNA-596 Biochimie (IF 3.188) Pub Date : 2019-04-14 Minghao Wei, Yidong Cao, Dong Jia, Haikang Zhao, Liang Zhang
Crataeva tapia bark lectin (CrataBL) is a chemoattractant for endothelial cells that targets heparan sulfate and promotes in vitro angiogenesis Biochimie (IF 3.188) Pub Date : 2019-04-12 Fabricio Pereira Batista, Rodrigo Barbosa de Aguiar, Joana Tomomi Sumikawa, Yara Aparecida Lobo, Camila Ramalho Bonturi, Rodrigo Ferreira da Silva, Sheila Siqueira Andrade, Patricia Maria Guedes Paiva, Maria Tereza dos Santos Correia, Carolina Meloni Vicente, Leny Toma, Misako Uemura Sampaio, Thaysa Paschoalin, Manoel João Batista Castello Girão, Jane Zveiter de Moraes, Cláudia Alessandra Andrade de Paula, Maria Luiza Vilela Oliva
GLUT1 is associated with sphingolipid-organized, cholesterol-independent domains in L929 mouse fibroblast cells Biochimie (IF 3.188) Pub Date : 2019-04-11 Lauren E. Rylaarsdam, Grace N. Johnecheck, Brendan D. Looyenga, Larry L. Louters
Glucose is a preferred metabolite in most mammalian cells, and proper regulation of uptake is critical for organism homeostasis. The glucose transporter 1 (GLUT1) is responsible for glucose uptake in a wide variety of cells and appears to be regulated in a tissue specific manner. Therefore, a better understanding of GLUT1 regulation within its various cellular environments is essential for developing therapeutic strategies to treat disorders associated with glucose homeostasis. Previous findings suggest that plasma membrane subdomains called lipid rafts may play a role in regulation of GLUT1 uptake activity. While studying this phenomenon in L929 mouse fibroblast cells, we observed that GLUT1 associates with a low density lipid microdomain distinct from traditionally-defined lipid rafts. These structures are not altered by cholesterol removal with methyl-ß-cyclodextrin and lack resistance to cold Triton X-100 extraction. Our data indicate that the GLUT1-containing membrane microdomains in L929 cells, as well as GLUT1’s basal activity, are instead sphingolipid-dependent, being sensitive to both myriocin and sphingomyelinase treatment. These microdomains appear to be organized primarily by their lipid composition, as disruption of the actin cytoskeleton or microtubules does not alter the association of GLUT1 with them. Furthermore, the association of GLUT1 with these microdomains appears not to require palmitoylation or glycosylation, as pharmacologic inhibition of these processes had no impact on GLUT1 density in membrane fractions. Importantly, we find no evidence that GLUT1 is actively translocated into or out of low density membrane fractions in response to acute activation in L929 cell.
In vivo assembly of eukaryotic signal recognition particle: a still enigmatic process involving the SMN complex Biochimie (IF 3.188) Pub Date : 2019-04-09 Séverine Massenet
The signal recognition particle (SRP) is a universally conserved non-coding ribonucleoprotein complex that is essential for targeting transmembrane and secretory proteins to the endoplasmic reticulum. Its composition and size varied during evolution. In mammals, SRP contains one RNA molecule, 7SL RNA, and six proteins: SRP9, 14, 19, 54, 68 and 72. Despite a very good understanding of the SRP structure and of the SRP assembly in vitro, how SRP is assembled in vivo remains largely enigmatic. Here we review current knowledge on how the 7SL RNA is assembled with core proteins to form functional RNP particles in cells. SRP biogenesis is believed to take place both in the nucleolus and in the cytoplasm and to rely on the survival of motor neuron complex, whose defect leads to spinal muscular atrophy.
Identification of a peptide derived from a Bothrops moojeni metalloprotease with in vitro inhibitory action on the Plasmodium falciparum purine nucleoside phosphorylase enzyme (PfPNP) Biochimie (IF 3.188) Pub Date : 2019-04-09 Gracianny Gomes Martins, Rudson de Jesus Holanda, Jorge Alfonso, Ana Fidelina Gómez Garay, Ana Paula de Azevedo dos Santos, Anderson Maciel de Lima, Aleff Ferreira Francisco, Carolina Bioni Garcia Teles, Fernando Berton Zanchi, Andreimar Martins Soares
Suppression in advanced glycation adducts of human serum albumin by bio-enzymatically synthesized gold and silver nanoformulations: A potential tool to counteract hyperglycemic condition Biochimie (IF 3.188) Pub Date : 2019-04-06 Faizan Ahmed, Qayyum Husain
Kinetics of inactivation of staphylolytic enzymes: qualitative and quantitative description Biochimie (IF 3.188) Pub Date : 2019-04-06 Lyubov Filatova, David Donovan, Steven Swift, Vladimir Pugachev, Georgy Emelianov, Tatiana Chubar, Natalia Klaychko
Lysin 2638aR and chimeric Ply187AN-KSH3b fusion protein are capable of lysing antibiotic-resistant strains of Staphylococcus aureus and are promising alternatives to antibiotics. Studies on the stability and structure of lysins 2638aR and Ply187AN-KSH3b are important for assessing the feasibility of their practical use. Both lysins are highly active at physiological pH (7.5) and at low salt content (the concentration of NaCl in the reaction medium is not more than 250 mM). Lysins are inactivated by a monomolecular mechanism and have high stability at 4°C (storage temperature). The maximum value of the half-inactivation time for lysin 2638aR is 190-200 days (500-1000 mM NaCl, pH 6.0-7.5), for lysin Ply187AN-KSH3b is 320-340 days (10-1000 mM NaCl, pH 6.0). The lysins are pretty stable in human blood serum (the half-inactivation time is 0.5-2 hours) at 37°C. The lysins undergo denaturation in large part due to the destruction of the α-helices at temperatures above 40°C.
The homeoprotein Msx1 cooperates with Pkn1 to prevent terminal differentiation in myogenic precursor cells Biochimie (IF 3.188) Pub Date : 2019-04-06 Xiaoli Zhu, Mingrui Li, Xiang Jia, Wanwan Hou, Jiange Yang, Hui Zhao, Gang Wang, Jingqiang Wang
The homeoprotein Msx1 plays a critical role in embryonic patterning, particularly to maintain myogenic progenitor cell fate. However, the mechanisms underlying Msx1-mediated inhibition of myogenesis remain largely unknown. Here, we show that Msx1 cooperates with the protein kinase C-related kinase 1 (Pkn1), a member of the protein kinase C-related kinase family, to prevent the terminal differentiation of myogenic precursor cells. In mouse C2C12 cells, Pkn1 knockout partly impaired Msx1-mediated inhibition of myogenic differentiation, indicating a role for Pkn1 in this process. Furthermore, we found that Pkn1 was required for Msx1 enrichment at the promoter of Myf5, a myogenic regulatory gene. In Pkn1 knockout cells, this reduced Msx1 enrichment at the Myf5 promoter coincided with attenuated repression of Myf5 transcription. Together with our observation that Msx1 and Pkn1 were associated in a protein complex, these findings strongly suggest that Msx1 cooperates with Pkn1 to down-regulate Myf5 and, therefore, prevent the differentiation of myogenic precursor cells. Collectively, our data provide key insights into the mechanisms underlying Msx1 function in the prevention of myogenic differentiation.
The apoptosis and GLP-1 hyposecretion induced by LPS via RIP/ROS/mTOR pathway in GLUTag cells Biochimie (IF 3.188) Pub Date : 2019-04-04 Jiao Wang, Xiang Wang, Zhi-Zhen Li, Feng Guo, Cheng-Zhi Ding, Yan-Yan Zhao, Yan-Ling Liu, Xiao-Jun Ma, Chong Li, Li-Na Wu, Qian Qin, Shui-Ying Zhao, Di Zhao, Xiao Hao, Shou-Jun Wang, Gui-Jun Qin
Lipopolysaccharide (LPS) as a component of the outer structure of cell wall of gram-negative bacteria, could induce apoptosis in the intestinal endocrine cell line STC-1. However, the signaling cascades involved in this process have not been elucidated. Hence, we investigated the mechanism of cell apoptosis and hyposecretion of glucagon-like peptide 1 (GLP-1) induced by LPS in the GLUTag enteroendocrine cell line. LPS decreased the cell viability of GLUTag cells, up-regulated the TNF-α level, induced the apoptosis and down-regulated the mRNA and protein levels of GLP-1. In addition, TNF-α promoted LPS-induced apoptosis of GLUTag cells through mediating the formation of the RIP1/RIP3 necrosome. RIP1 and RIP3 knockdown increased cell viability, the mRNA and protein levels of GLP-1 and the mTOR signaling pathway-related proteins (p-mTOR and p-S6), and decreased the relative caspase 3/7 activity, cell apoptosis and ROS production. Further studies showed that ROS inhibited the mTOR signaling pathway. Moreover, the antioxidant N-acetyl-L-cysteine increased cell viability, GLP-1 expressions and the mTOR signaling pathway-related proteins, and inhibited the ROS production. However, the mTOR specific inhibitor (Rapa) reversed all these above effects. Taken together, our result revealed that LPS induced the apoptosis of GLUTag cells and GLP-1 hyposecretion through the RIP/ROS/mTOR pathway.
Serotonin and orthodontic tooth movement Biochimie (IF 3.188) Pub Date : 2019-04-03 Thomas Dhenain, Francine Côté, Tereza Coman
Peripheral serotonin continuously reveals its unexpected involvements in many organ functions. In bone tissue, there is an increasing evidence for a local serotonergic system affecting the cellular and molecular actors involved in bone turnover. During orthodontic treatment, tooth movement relies on bone remodeling, itself a result of the inflammatory process triggered by application of orthodontic forces to the teeth. Nowadays, many adults proceed to an orthodontic treatment, it therefore seems important to consider physiological growth-related factors and external factors as medications that may influence adverse effects and efficacy of orthodontic treatment techniques. In this review, we focus on peripheral serotonin mechanism of regulation of bone remodeling during orthodontic movement. We discuss the differential effect of serotonin on alveolar bone inflammation that may open new strategies in orthodontics.
Biochemical and molecular characterization of the hyaluronidase from Bothrops atrox Peruvian snake venom Biochimie (IF 3.188) Pub Date : 2019-04-01 Dan E. Vivas-Ruiz, Edgar E. Gonzalez-Kozlova, Julio Delgadillo, Pedro M. Palermo, Gustavo A. Sandoval, Fanny Lazo, Edith Rodríguez, Carlos Chávez-Olórtegui, Armando Yarlequé, Eladio F. Sanchez
Snake venoms are a rich source of enzymes such as metalloproteinases, serine proteinases phospholipases A2 and myotoxins, that have been well characterized structurally and functionally. However, hyaluronidases (E.C.188.8.131.52) have not been studied extensively. In this study, we describe the biochemical and molecular features of a hyaluronidase (Hyal-Ba) isolated from the venom of the Peruvian snake Bothrops atrox. Hyal-Ba was purified by a combination of ion-exchange and gel filtration chromatography. Purified Hyal-Ba is a 69-kDa (SDS-PAGE) monomeric glycoprotein with an N-terminal amino acid sequence sharing high identity with homologous snake venom hyaluronidases. Detected associated carbohydrates were hexoses (16.38%), hexosamines (2.7%) and sialic acid (0.69%). Hyal-Ba selectively hydrolyzed only hyaluronic acid (HA; specific activity = 437.5 U/mg) but it did not hydrolyze chondroitin sulfate or heparin. The optimal pH and temperature for maximum activity were 6.0 and 40°C, respectively, and its Km was 0.31 μM. Its activity was inhibited by EDTA, iodoacetate, 2-mercaptoethanol, TLCK and dexamethasone. Na+ and K+ (0.2 M) positively affect hyaluronidase activity; while Mg2+, Br2+, Ba2+, Cu2+, Zn2+, and Cd2+ reduced catalytic activity. Hyal-Ba potentiates the hemorrhagic and hemolytic activity of whole venom, but decreased subplantar edema caused by an L-amino acid oxidase (LAAO). The Hyal-Ba cDNA sequence (2020 bp) encodes 449 amino acid residues, including the catalytic site residues (Glu135, Asp133, Tyr206, Tyr253 and Trp328) and three functional motifs for N-linked glycosylation, which are conserved with other snake hyaluronidases. Spatial modeling of Hyal-Ba displayed a TIM-Barrel (α/β) fold and an EGF-like domain in the C-terminal portion. The phylogenetic analysis of Hyal-Ba with other homologous Hyals showed the monophyly of viperids. Further, Hyal-Ba studies may extend our knowledge of B. atrox toxinology and provides insight to improve the neutralizing strategies of therapeutic antivenoms.
Serotonin-estrogen interactions: what can we learn from pregnancy? Biochimie (IF 3.188) Pub Date : 2019-04-01 Andrée-Anne Hudon Thibeault, J. Thomas Sanderson, Cathy Vaillancourt
We have reviewed the scientific literature related to four diseases in which to serotonin (5-HT) is involved in the etiology, herein named 5-HT-linked diseases, and whose prevalence is influenced by estrogenic status: depression, migraine, irritable bowel syndrome and eating disorders. These diseases all have in common a sex-dimorphic prevalence, with women more frequently affected than men. The co-occurrence between these 5-HT-linked diseases suggests that they have common physiopathological mechanisms. In most 5-HT-linked diseases (except for anorexia nervosa and irritable bowel syndrome), a decrease in the serotonergic tone is observed and estrogens are thought to contribute to the improvement of symptoms by stimulating the serotonergic system. Human pregnancy is characterized by a unique 5-HT and estrogen synthesis by the placenta. Pregnancy-specific disorders, such as hyperemesis gravidarum, gestational diabetes mellitus and pre-eclampsia, are associated with a hyperserotonergic state and decreased estrogen levels. Fetal programming of 5-HT-linked diseases is a complex phenomenon that involves notably fetal-sex differences, which suggest the implication of sex steroids. From a mechanistic point of view, we hypothesize that estrogens regulate the serotonergic system, resulting in a protective effect against 5-HT-linked diseases, but that, in turn, 5-HT affects estrogen synthesis in an attempt to retrieve homeostasis. These two processes (5-HT and estrogen biosynthesis) are crucial for successful pregnancy outcomes, and thus, a disruption of this 5-HT-estrogen relationship may explain pregnancy-specific pathologies or pregnancy complications associated with 5-HT-linked diseases.
An ancient mechanism of arginine-specific substrate cleavage: what’s up with NSP4? Biochimie (IF 3.188) Pub Date : 2019-04-01 Andrew P. AhYoung, S. Jack Lin, Stefan Gerhardy, Menno van Lookeren Campagne, Daniel Kirchhofer
The recently discovered neutrophil serine protease 4 (NSP4) is the fourth member of the NSP family, which includes the well-studied neutrophil elastase, proteinase 3 and cathepsin G. Like the other three NSP members, NSP4 is synthesized by myeloid precursors in the bone marrow and, after cleavage of the two-amino acid activation peptide, is stored as an active protease in azurophil granules of neutrophils. Based on its primary amino acid sequence, NSP4 is predicted to have a shallow S1 specificity pocket with elastase-like substrate specificity. However, NSP4 was found to preferentially cleave after an arginine residue. Structural studies resolved this paradox by revealing an unprecedented mechanism of P1-arginine recognition. In contrast to the canonical mechanism in which the P1-arginine residue points down into a deep S1 pocket, the arginine side chain adopts a surface-exposed ‘up’ conformation in the NSP4 active site. This conformation is stabilized by the Phe190 residue, which serves as a hydrophobic platform for the aliphatic portion of the arginine side chain, and a network of hydrogen bonds between the arginine guanidium group and the NSP4 residues Ser192 and Ser216. This unique configuration allows NSP4 to cleave even after naturally modified arginine residues, such as citrulline and methylarginine. This non-canonical mechanism, characterized by the hallmark ‘triad’ Phe190-Ser192-Ser216, is largely preserved throughout evolution starting with bony fish, which appeared about 400 million years ago. Although the substrates and physiological role of NSP4 remain to be determined, its remarkable evolutionary conservation, restricted tissue expression and homology to other neutrophil serine proteases anticipate a function in immune-related processes.
Design of cross-linked RNA/protein complexes for structural studies Biochimie (IF 3.188) Pub Date : 2019-03-30 Clément Dégut, Veronika Schwarz, Luc Ponchon, Pierre Barraud, Ronald Micura, Carine Tisné
Crystallographic studies of RNA/protein complexes are primordial for the understanding of recognition determinants and catalytic mechanisms in the case of enzymes. However, due to the flexibility and propensity to conformational heterogeneity of RNAs, as well as the mostly electrostatic interactions of RNA/protein complexes, they are difficult to crystallize. We present here a method to trap the two interacting partners in a covalent complex, based on a modified reactive RNA allowing the use of the full range of common crystallogenesis tools. We demonstrate the practicability of our approach with the production of a covalent complex of the Thermus thermophilus m1A58 tRNA modification enzyme, and a modified stem loop mimicking the natural substrate of the enzyme.
Repurposing of auranofin: thioredoxin reductase remains a primary target of the drug Biochimie (IF 3.188) Pub Date : 2019-04-01 Xiaonan Zhang, Karthik Selvaraju, Amir Ata Saei, Padraig D'Arcy, Roman A. Zubarev, Elias SJ. Arnér, Stig Linder
Sex-specific polymorphism of MET1 and ARR17 genes in Populus × sibirica Biochimie (IF 3.188) Pub Date : 2019-03-29 Nataliya V. Melnikova, Anna V. Kudryavtseva, Elena V. Borkhert, Elena N. Pushkova, Maria S. Fedorova, Anastasiya V. Snezhkina, George S. Krasnov, Alexey A. Dmitriev
The genus Populus is an effective model in tree genetics. This genus includes dioecious species and, recently, whole genome resequencing of P. trichocarpa and P. balsamifera enabled the identification of sex-linked regions and sex-associated single nucleotide polymorphisms (SNPs). These results created new opportunities to study sex determination in poplars. In the present work, we performed deep sequencing of genes encoding METHYLTRANSFERASE1 (MET1) and homolog of ARABIDOPSIS RESPONSE REGULATOR 17 (ARR17), which are localized in a sex-linked region of Populus genome and contain a number of sex-associated SNPs. Amplicon libraries for 38 samples of P. × sibirica (19 males and 19 females) were sequenced on MiSeq Illumina (300 nt paired-end reads) and approximately 4000x coverage was obtained for each sample. In total, from 80 to 179 SNPs were detected in poplar individuals for MET1, and from 16 to 49 SNPs were detected for ARR17. We identified 17 sex-specific SNPs (11 in MET1 and 6 in ARR17) – they were present in all males but absent in all females. For identified sex-specific SNP sites, females were homozygous, while males were heterozygous. Moreover, colocation of sex-specific SNPs confirming the XY sex-determination system of poplars was revealed: in one allelic variant, males had the same nucleotides as females, while in the other, sex-specific SNPs were present. Based on the data obtained, we developed and successfully applied a high-resolution melting-based approach for sex identification in poplars. The developed molecular markers are useful for distinguishing between male and female poplars in scientific research and can also be applied to select male-only genotypes for use in city landscaping and production of paper, pulp, and biofuel.
Dual cellular localization of the Leishmania amazonensis Rbp38 (LaRbp38) explains its affinity for telomeric and mitochondrial DNA Biochimie (IF 3.188) Pub Date : 2019-03-28 Carlos A.H. Fernandes, Arina M. Perez, Andrea C. Barros, Thiago R. Dreyer, Marcelo S. da Silva, Edna Gicela O. Morea, Marcos R.M. Fontes, Maria Isabel N. Cano
Rbp38 is a protein exclusively found in trypanosomatid parasites, including Leishmania amazonensis, the etiologic agent of tegumentar leishmaniasis in the Americas. The protein was first described as a Leishmania tarentolae mitochondrial RNA binding protein. Later, it was shown that the trypanosomes Rbp38 orthologues were exclusively found in the mitochondria and involved in the stabilization and replication of kinetoplast DNA (kDNA). In contrast, L. amazonensis Rbp38 (LaRbp38), co-purifies with telomerase activity and interacts not only with kDNA but also with telomeric DNA, although shares with its counterparts high sequence identity and a putative N-terminal mitochondrial targeting signal (MTS). To understand how LaRbp38 interacts both with nuclear and kDNA, we have first investigated its subcellular localization. Using hydroxy-urea synchronized L. amazonensis promastigotes we could show that LaRbp38 shuttles from mitochondria to the nucleus at late S and G2 phases. Further, we identified a non-classical nuclear localization signal (NLS) at LaRbp38 C-terminal that binds with importin alpha, a protein involved in the nuclear transport of several proteins. Also, we obtained LaRbp38 truncated forms among which, some of them also showed an affinity for both telomeric DNA and kDNA. Analysis of these truncated forms showed that LaRbp38 DNA-binding region is located between amino acid residues 95-235. Together, our findings strongly suggest that LaRbp38 is multifunctional with dual subcellular localization.
Structural insights into the 3’-end mRNA maturation machinery: snapshot on Polyadenylation signal recognition Biochimie (IF 3.188) Pub Date : 2019-03-28 Stéphane Thore, Sébastien Fribourg
Pre-mRNA 3’-end maturation is achieved by a mechanism requiring four different protein complexes assembled from approximately twenty factors. A global understanding of this essential process is still missing due to the inability to structurally characterize the entire complexes, even though structures of the isolated factors have been obtained. In this review, we summarize recent findings regarding the atomic description of one the major players, the Cleavage and Polyadenylation Specificity Factor complex (CPSF in human, CPF in yeast). These data provide information on the architecture adopted by the major components of this complex, and on its capacity to recognize the polyadenylation signal sequence.
Differential micro-RNA expression in diabetic patients with abdominal aortic aneurysm Biochimie (IF 3.188) Pub Date : 2019-03-26 Fabien Lareyre, Marc Clément, Claudine Moratal, Xavier Loyer, Elixène Jean-Baptiste, Réda Hassen-Khodja, Giulia Chinetti, Ziad Mallat, Juliette Raffort
Objectives The potential implication of micro-RNAs (miRs) in the negative association between diabetes and abdominal aortic aneurysm (AAA) has so far never been addressed. The aim of this study was to compare miR expression between diabetic and non-diabetic patients with AAA. Methods Ten diabetic patients were prospectively included and compared to 10 age- and sex-matched non-diabetic patients with infrarenal AAA. A profiling analysis of 752 human miRs was performed from peripheral blood mononuclear cells (PBMCs) using miRCURY LNA Universal RT microRNA PCR (Exiqon- Qiagen®). miR that showed significant differential expression (P <0.05) were selected and further analyzed in the entire cohort in sera, plasma and aneurysmal aortic tissues. Results Four miRs were significantly differentially expressed in PBMCs of diabetic patients compared to non-diabetics: 3 were upregulated (miR-144-3p, 20a-5p and 188-3p) and 1 downregulated (miR-548k). miR-144-3p and miR-548k were also increased in aneurysmal tissue and miR-20a-5p was increased in serum. The expression of miR-20a-5p in PBMCs was correlated with fructosamine concentration (r=0.62, p=0.006). Conclusions Even if further studies are required to determine their direct role in AAA, these miRs could represent interesting new targets.
The yeast C/D box snoRNA U14 adopts a “weak” K-turn like conformation recognized by the Snu13 core protein in solution Biochimie (IF 3.188) Pub Date : 2019-03-23 Marie-Eve Chagot, Marc Quinternet, Benjamin Rothé, Bruno Charpentier, Jérôme Coutant, Xavier Manival, Isabelle Lebars
Non-coding RNAs associate with proteins to form ribonucleoproteins (RNPs), such as ribosome, box C/D snoRNPs, H/ACA snoRNPs, ribonuclease P, telomerase and spliceosome to ensure cell viability. The assembly of these RNA-protein complexes relies on the ability of the RNA to adopt the correct bound conformation. K-turn motifs represent ubiquitous binding platform for proteins found in several cellular environment. This structural motif has an internal three-nucleotide bulge flanked on its 3’ side by a G●A/A●G tandem pairs followed by one or two non-Watson-Crick pairs, and on its 5’ side by a classical RNA helix. This peculiar arrangement induces a strong curvature of the phosphodiester backbone, which makes it conducive to multiple tertiary interactions. SNU13/Snu13p (Human/Yeast) binds specifically the U14 C/D box snoRNA K-turn sequence motif. This event is the prerequisite to promote the assembly of the RNP, which contains NOP58/Nop58 and NOP56/Nop56 core proteins and the 2'-O-methyl-transferase, Fibrillarin/Nop1p. The U14 small nucleolar RNA is a conserved non-coding RNA found in yeast and vertebrates required for the pre-rRNA maturation and ribose methylation. Here, we report the solution structure of the free U14 snoRNA K-turn motif (kt-U14) as determined by Nuclear Magnetic Resonance. We demonstrate that a major fraction of free kt-U14 adopts a pre-folded conformation similar to protein bound K-turn, even in the absence of divalent ions. In contrast to the kt-U4 or tyrS RNA, kt-U14 displays a sharp bent in the phosphodiester backbone. The U●U and G●A tandem base pairs are formed through weak hydrogen bonds. Finally, we show that the structure of kt-U14 is stabilized upon Snu13p binding. The structure of the free U14 RNA is the first reference example for the canonical motifs of the C/D box snoRNA family.
Imaging of extracellular cathepsin S activity by a selective near infrared fluorescence substrate-based probe Biochimie (IF 3.188) Pub Date : 2019-03-23 Mylène Wartenberg, Ahlame Saidi, Mathieu Galibert, Alix Joulin-Giet, Julien Burlaud-Gaillard, Fabien Lecaille, Christopher J. Scott, Vincent Aucagne, Agnès F. Delmas, Gilles Lalmanach
HIV-1 gRNA, a biological substrate, uncovers the potency of DDX3X biochemical activity Biochimie (IF 3.188) Pub Date : 2019-03-22 Grégoire de Bisschop, Mélissa Ameur, Nathalie Ulryck, Fatima Benattia, Luc Ponchon, Bruno Sargueil, Nathalie Chamond
DEAD-box helicases play central roles in the metabolism of many RNAs and ribonucleoproteins by assisting their synthesis, folding, function and even their degradation or disassembly. They have been implicated in various phenomena, and it is often difficult to rationalize their molecular roles from in vivo studies. Once purified in vitro, most of them only exhibit a marginal activity and poor specificity. The current model is that they gain specificity and activity through interaction of their intrinsically disordered domains with specific RNA or proteins. DDX3 is a DEAD-box cellular helicase that has been involved in several steps of the HIV viral cycle, including transcription, RNA export to the cytoplasm and translation. In this study, we investigated DDX3 biochemical properties in the context of a biological substrate. DDX3 was overexpressed, purified and its enzymatic activities as well as its RNA binding properties were characterized using both model substrates and a biological substrate, HIV-1 gRNA. Biochemical characterization of DDX3 in the context of a biological substrate identifies HIV-1 gRNA as a rare example of specific substrate and unravels the extent of DDX3 ATPase activity. Analysis of DDX3 binding capacity indicates an unexpected dissociation between its binding capacity and its biochemical activity. We further demonstrate that interaction of DDX3 with HIV-1 gRNA relies both on specific RNA determinants and on the disordered N- and C-terminal regions of the protein. These findings shed a new light regarding the potentiality of DDX3 biochemical activity supporting its multiple cellular functions.
Heavy metal hypertolerant eukaryotic aldehyde dehydrogenase isolated from metal contaminated soil by metatranscriptomics approach Biochimie (IF 3.188) Pub Date : 2019-03-21 Arkadeep Mukherjee, Rajiv Yadav, Roland Marmeisse, Laurence Fraissinet-Tachet, M. Sudhakara Reddy
MicroRNA-34 suppresses proliferation of human ovarian cancer cells by triggering autophagy and apoptosis and inhibits cell invasion by targeting Notch 1 Biochimie (IF 3.188) Pub Date : 2019-03-21 Yan Jia, Ruixin Lin, Hongjuan Jin, Lihui Si, Wenwen Jian, Qing Yu, Shuli Yang
Ovarian cancer is one the prevalent cancers in women and is responsible for 5% of all the cancer related mortalities in women. Owing to late diagnosis, frequent relapses, side effects of chemotherapy, development of drug resistance, there is pressing need to screen out novel and effective treatment options. Accumulating evidences suggest that miRNAs may prove essential therapeutic targets for the treatment of cancer. This study was designed to investigate the role and therapeutic potential of miR-34 in ovarian cancer. It was found that miR-34 is significantly downregulated in ovarian cancer cell lines. Overexpression of miR-34 causes significant decrease in the proliferation of OVACAR-3 ovarian cancer cells via activation of apoptosis and autophagy. The miR-34 overexpression was concomitant with upsurge of apoptosis related proteins (Bax) and the autophagy associated protein (LC3 II and p62). TargetScan analysis showed Notch 1 to be the main target of miR-34 in OVACAR-3 cells which was further validated by luciferase reporter assay. The qRT-PCR results showed Notch 1 to be 3.2 to 4.1 fold higher in the ovarian cancer cell lines relative to the non-cancerous cells. Nonetheless, miR-34 overexpression in OVACAR-3 cells resulted in the post-transcriptional suppression of Notch 1 expression. Silencing of Notch 1 also caused inhibition of OVACAR-3 cell proliferation via induction of apoptosis and autophagy. Overexpression of Notch 1 could partially rescue the effects of miR-34 overexpression on the proliferation of OVACAR-3 cells. Moreover, overexpression of miR-34 causes significant inhibition of the invasion of the OVACAR-3 cells. The findings of the present study indicate the tumor suppressive role of miR-34 in ovarian cancer and may therefore prove to be a potential therapeutic target.
Highly active extracellular α-class carbonic anhydrase of Cyanothece sp. ATCC 51142 Biochimie (IF 3.188) Pub Date : 2019-03-18 Elena V. Kupriyanova, Maria A. Sinetova, Kirill S. Mironov, Galina V. Novikova, Lev A. Dykman, Margarita V. Rodionova, David A. Gabrielyan, Dmitry A. Los
Here, for the first time, we report the presence of highly active extracellular carbonic anhydrase (CA) of α-class in cyanobacterial cells. The enzyme activity was confirmed both in vivo in intact cells and in vitro, using the recombinant protein. CA activity in intact cells of Cyanothece sp. ATCC 51142 reached ∼ 0.6 Wilbur–Anderson units (WAU) per 1 mg of total cell protein, and it was inhibited by a specific CAs inhibitor, ethoxyzolamide. The genes cce_4328 (ecaA) and cce_0871 (ecaB), encoding two potential extracellular CAs of Cyanothece have been cloned, and the corresponding proteins EcaA and EcaB, representing CAs of α- and β-class, respectively, have been heterologously expressed in Escherichia coli. High specific activity (∼1.1×104 WAU per 1 mg of target protein) was detected for the recombinant EcaA only. The presence of EcaA in the outer cellular layers of Cyanothece was confirmed by immunological analysis with antibodies raised against the recombinant protein. The absence of redox regulation of EcaA activity indicates that this protein does not possess a disulfide bond essential for some α-class CAs. The content and activity of EcaA in a fraction of periplasmic proteins was higher in Cyanothece cells grown at ambient concentration of CO2 (0.04%) compared to those grown at an elevated CO2 concentration (1.7%). At the same time, the level of ecaA gene mRNA varied insignificantly in response to changes in CO2 supply. Our results indicate that EcaA is responsible for CA activity of intact Cyanothece cells and point to its possible physiological role of EcaA under low-CO2 conditions.
Periostin contributes to renal and cardiac dysfunction in rats with chronic kidney disease: reduction of PPARα Biochimie (IF 3.188) Pub Date : 2019-03-16 Xiaohui Bian, Xiaoxiao Su, Yanqiu Wang, Guifeng Zhao, Beiru Zhang, Detian Li
POSTN knockdown inhibits the formation of NLRP3 inflammasome in rat myocardium.Periostin (POSTN), an extracellular matrix protein, and peroxisome proliferator-activated receptor alpha (PPARα), a ligand-activated nuclear transcription factor, are reported to be involved in renal and cardiac dysfunction associated with chronic kidney disease (CKD), respectively. This study is performed to investigate how POSTN-PPARα axis affects the progress of CKD. In vivo, adenovirus particles containing POSTN short hairpin RNA (Ad-shPOSTN) were intravenously given to Sprague Dawley rats following 5/6 nephrectomy. The effects of Ad-shPOSTN on CKD and CKD-associated cardiovascular disease were evaluated. In vitro, NRK-52E renal tubular epithelial cells were infected with Ad-shPOSTN or Ad-POSTN (overexpression) to explore whether POSTN affected collagen deposition by regulating PPARα. We found that POSTN expression was upregulated, while PPARα was downregulated in the injured renal and left ventricular tissues of nephrectomized rats. Ad-shPOSTN improved renal function, prevented cardiac dysfunction, and attenuated organ fibrosis in nephrectomized rats. The expression levels of renal and myocardial PPARα were increased following Ad-shPOSTN administration. Furthermore, POSTN silencing suppressed the formation of NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome in the myocardium: the levels of NLRP3, anti-apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), cleaved caspase 1, mature interleukin (IL)-1β and IL-18 were reduced. In NRK-52E cells, forced overexpression of POSTN directly inhibited PPARα expression and induced collagen deposition. WY14643, a PPARα agonist, suppressed POSTN-induced collagen deposition. In summary, our study demonstrates that POSTN negatively regulates PPARα expression. Targeting POSTN-PPARα axis may present a novel protective intervention to alleviate CKD and CKD-associated cardiac dysfunction.
Primers on nutrigenetics and nutri(epi)genomics: origins and development of precision nutrition Biochimie (IF 3.188) Pub Date : 2019-03-13 Bordoni Laura, Gabbianelli Rosita
Characterization of the Nicotinamide Adenine Dinucleotides (NAD+ and NADP+) Binding Sites of the Monomeric Isocitrate Dehydrogenases from Campylobacter species Biochimie (IF 3.188) Pub Date : 2019-03-12 Peng Wang, Xuefei Chen, Jing Yang, Yunyun Pei, Mingjie Bian, Guoping Zhu
Monomeric isocitrate dehydrogenases (IDHs) have once been proposed to be exclusively NADP+-specific. Intriguingly, we recently have reported an NAD+-specific monomeric IDH from Campylobacter sp. FOBRC14 (CaIDH). Moreover, bioinformatic analysis revealed at least three different coenzyme-binding motifs among Campylobacter IDHs. Besides the NAD+-binding motif in CaIDH (Leu584/Asp595/Ser644), a typical NADP+-binding motif was also identified in Campylobacter corcagiensis IDH (CcoIDH, His582/Arg593/Arg638). Meanwhile, a third putative NAD+-binding motif was found in Campylobacter concisus IDH (CcIDH, Leu580/Leu591/Ala640). In this study, CcIDH was overexpressed in Escherichia coli and purified to homogeneity. Gel filtration chromatography demonstrated that the recombinant CcIDH exists as a monomer in solution. Kinetic analysis showed that the Km value of CcIDH for NADP+ was over 49-fold higher than that for NAD+ and the catalytic efficiency (kcat/Km) of CcIDH is 115-fold greater for NAD+ than NADP+. Thus, CcIDH is indeed an NAD+-specific enzyme. However, the catalytic efficiency (kcat/Km=0.886 μM-1 s-1) of CcIDH for NAD+ is much lower (<5%) when compared to that of the typical monomeric NADP-IDHs for NADP+. Then, the three core NAD+-binding sites were evaluated by site-directed mutagenesis. The mutant CcIDH (H580R591R640) showed a 51-fold higher Km value for NAD+ and 21-fold lower Km value for NADP+ as compared to that of the wild type enzyme, respectively. The overall specificity of the mutant CcIDH was 12-fold greater for NADP+ than that for NAD+. Thus, the coenzyme specificity of CcIDH was converted from NAD+ to NADP+. Isocitrate dependence of enzyme kinetics showed that although the mutant H580R591R640 preferred NADP+ as its coenzyme, its catalytic efficiency for isocitrate reduced to half of that for the wild-type CcIDH as using NAD+. The finding of both NAD+ and NADP+-binding sites in monomeric IDHs from Campylobacter species will provide us a chance to explore the evolution of the coenzyme specificity in monomeric IDH subfamily.
Impact of proteolysis on cancer stem cell functions Biochimie (IF 3.188) Pub Date : 2019-03-12 Larissa E. Hillebrand, Thomas Reinheckel
Cancer cells within a tumor are heterogeneous and exist in a variety of functionally distinct cell states, which are thought to be hierarchically organized. The cell on top of this hierarchy, the cancer stem cell (CSC) or, alternatively, tumor initiating cell (TIC), is responsible for initiation, maintenance, progression, and relapse of tumors. For the execution of these functions, CSC are equipped with distinct molecular tools. Although proteolytic enzymes in cancers have been extensively studied in general, relatively few studies have addressed proteases in function and fate of CSC/TICs. Here we review protease involvement in cell biological hallmarks of CSC/TICs such as cellular self-renewal, extracellular matrix remodeling and cell motility, resistance to radio- and chemotherapies, as well as evasion of the immune system. In general, CSC/TICs are characterized by a comparatively high expression and activity of proteases. It appears that CSC/TICs install a high degree of pericellular proteolysis depending on metalloproteases such as ADAMs and MMPs but also on secreted serine- and cysteine proteases. Interestingly, it turned out that not all proteases promote the malignant behavior of CSC/TICs. In fact, some proteases, such as ADAM 23, cathepsin K, and granzyme B, have been shown to negatively regulate CSC/TIC functions, thereby exhibiting anti-tumor effects. Finally, we discuss how the enhanced proteolytic signature of CSC/TICs can be used for their therapeutic targeting in order to render this clinically decisive subpopulation of cancer cells harmless.
Cyanidin-3-glucoside induces mesenchymal to epithelial transition via activating Sirt1 expression in triple negative breast cancer cells Biochimie (IF 3.188) Pub Date : 2019-03-12 Lingwei Liang, Xipeng Liu, Jieyi He, Ying Shao, Jiao Liu, Zhiying Wang, Lina Xia, Ting Han, Peiying Wu
Triple-negative breast cancer (TNBC) is a heterogeneous group of breast cancer with one common feature: distinctly metastatic nature with higher rate of relapse and shorter survival compared with other subtypes of breast cancer. The epithelial to mesenchymal transition (EMT) is highly associated with cancer metastasis. Cyanidin-3-glucoside (C3G), the most abundant anthocyanin pigment enriched in fresh fruits and vegetables, showed ideal anti-oxidant property. C3G could also inhibit certain malignant behaviors of cancer cells, however, whether repression of EMT was involved in its anti-cancer especially TNBC effect remains unknown. Herein, we report that C3G decreases the migratory and invasive nature of TNBC lines MDA-MB-231 and BT-549. Mechanistically, C3G induces reversion of EMT characterized by phenotype modulation with increased epithelial marker E-ca and ZO-1, decreased mesenchymal marker Vimentin, N-ca and EMT-associated transcription factors Snail1, Snail2. NF-κB is pivotal for EMT and Sirt1 is a NF-κB inhibitor. We show that NF-κB is attenuated and Sirt1 is induced by C3G in TNBC, respectively. And later evidence demonstrates that abrogation of Sirt1 with small interfering RNA transfection abolished NF-κB inhibition and EMT reversion by C3G. Subsequently, we show that microRNA-138(miR-138) represses Sirt1 via mRNA translation inhibition and is inhibited by C3G. Moreover, miR-138 repression is involved in Sirt1 re-activation and migratory and invasive inhibition of TNBC by C3G. Taken together, we supplied more evidence to the anti-breast cancer mechanisms of C3G.
LC-MSMS Characterisations of scymnol and oxoscymnol biotransformations in incubation mixtures of rat liver microsomes Biochimie (IF 3.188) Pub Date : 2019-03-04 Linda L. Glowacki, Lynn D. Hodges, Paul M. Wynne, Paul F.A. Wright, Nicolette Kalafatis, Theodore A. Macrides
The bile alcohol 5β-scymnol ([24R]-(+)-5β-cholestan-3α,7α,12α,24,26,27-hexol) is a therapeutic nutraceutical derived from marine sources, however very little is known about its potential for biotransformation as a xenobiotic in higher vertebrates. In this study, biotransformation products of scymnol catalysed by liver microsomes isolated from normal and streptozotocin (STZ)-treated male Wistar rats were characterised by liquid chromatography-tandem mass spectroscopy (LC-MSMS). In order of increasing polarity relative to the reversed phase sorbent, structural assignments were made for four biotransformation products, namely 3-oxoscymnol (5β-cholestan-3-one-7α,12α,24,26,27-pentol); 7-oxoscymnol (5β-cholestan-7-one-3α,12α,24,26,27-pentol); 3β-scymnol (5β-cholestan-3β,7α,12α,24,26,27-hexol) and 6β-hydroxyscymnol (5β-cholestan-3α,6β,7α,12α,24,26,27-heptol). In addition, a total of eight biotransformation products were characterised from microsomal incubations of crude oxoscymnol compounds, namely 7β-scymnol; 3,12-dioxoscymnol; 3,7-dioxoscymnol; 7,12-dioxoscymnol; 12-oxo-3β-scymnol; 7-oxo-3β-scymnol; 6β-hydroxy-12-oxoscymnol and 6β-hydroxy-7-oxoscymnol. Collectively, the results indicate hepatic enzyme-catalysed hydroxylation, dehydrogenation and epimerisation reactions on the steroid nucleus of scymnol, and provide an insight into biotransformation pathways for scymnol use as a therapeutic nutraceutical in higher vertebrates.
Conformational features of intramolecular G4-DNA constrained by single-nucleotide loops Biochimie (IF 3.188) Pub Date : 2019-03-03 Artemy Beniaminov, Anna Shchyolkina, Dmitry Kaluzhny
Conformation of the telomeric DNA fragment dG3(TTAG3)3 depends on multiple factors including solution conditions, length, and the nucleotide sequence of the flanking regions. In potassium solution, this sequence tends to adopt hybrid (3 + 1) G-quadruplex (G4) Form 1 or Form 2 conformation contingent on the flanking nucleotides. Theoretically, other (3 + 1) G4 folds (beyond Forms 1 and 2) are not sterically forbidden, but are presumably energetically disfavored. We report here on the effect of substituting the TTA loop with a single T nucleotide for one, two, or three loops of telomeric DNA that allowed us to expand the conformational diversity of the G4 DNA. Circular dichroism, gel migration, and chemical probing with DMS and ZnP1 (a porphyrin derivative sensitive to G4 conformation) were applied to monitor conformations that occurred upon shortening each loop to a single nucleotide. We found that all oligonucleotide models formed an intramolecular quadruplex structure and that shortening the loops led to the prevalence of G4 with quartets of the same polarity. Despite similar CD signatures, each modified sequence had one of three specific patterns of light-induced oxidation with ZnP1. According to the predominant modification pattern, folding of each sequence could be assigned to one of three major G4 conformations: parallel and two different (3 + 1) G4 folds. We here provide novel experimental evidence of the propensity for modified telomeric sequences to form a (3 + 1) G4 conformer containing one lateral and two propeller loops.
Grem2 Mediates Podocyte Apoptosis in High Glucose Milieu Biochimie (IF 3.188) Pub Date : 2019-03-01 Hongxiu Wen, Vinod Kumar, Abheepsa Mishra, Su Song, Rukhsana Aslam, Ali Hussain, Haichao Wang, Xiaogang Zhou, Xiaoming He, Guisheng Wu, Huairong Luo, Xiqian Lan, Ashwani Malhotra, Pravin C. Singhal
Background Increased DAN protein (Grem1, Grem2, Grem3, Cerberus, NBL1, SOST, and USAG1) levels are often associated with severe disease-states in adult kidneys. Grem1, SOST, and USAG1 have been demonstrated to be upregulated and play a critical role in the progression of diabetic nephropathy (DN); however, the expression and the role of other DAN family members in DN have not been reported yet. In this study, we investigated the expression and the role of Grem2 in the development of renal lesions in mice with type 2 DN. Methods Fourteen-week-old BTBRob/ob (a mouse model of type 2 diabetes mellitus) and control (BTBR, wild type) mice were evaluated for renal functional and structural biomarkers. Urine was collected for protein content assay, and renal tissues were harvested for molecular analysis with real-time PCR, Western blotting, and immunohistochemistry. In vitro studies, human podocytes were transfected with Grem2 plasmid and were evaluated for apoptosis (morphologic assay and Western blotting). To evaluate the Grem2-mediated downstream signaling, the phosphorylation status of Smad2/3 and Smad1/5/8 was assessed. To establish a causal relationship, the effect of SIS3 (an inhibitor for Samd2/3) and BMP-7 (an agonist for Smad1/5/8) was evaluated on Germ2-induced podocyte apoptosis. Results BTBRob/ob mice showed elevated urinary protein levels. Renal tissues of BTBRob/ob mice showed an increased expression of Grem2; both glomerular and tubular cells displayed enhanced Grem2 expression. In vitro studies, high glucose increased Grem2 expression in cultured human podocytes, whereas, Grem2 silencing partially protected podocyte from high glucose-induced apoptosis. Overexpression of Grem2 in podocytes not only increased Bax/Bcl2 expression ratio but also promoted podocyte apoptosis; moreover, an overexpression of Grem2 increased the phosphorylation of Smad2/3 and decreased the phosphorylation of Smad1/5/8; furthermore, SIS3 and BMP-7 attenuated Grem2-induced podocyte apoptosis. Conclusions High glucose increases Grem2 expression in kidney cells. Grem2 mediates podocyte apoptosis through Smads.
A novel fluorescence based assay for the detection of organophosphorus pesticide exposed cholinesterase activity using 1-naphthyl acetate Biochimie (IF 3.188) Pub Date : 2019-02-26 Sheemona Chowdhary, Rajasri Bhattacharyya, Dibyajyoti Banerjee
Acetylcholinesterase (AChE) is the primary target of organophosphorus pesticides (OPs). Ellman’s method using Acetylthiocholine (ATCh) is the standard approach for the detection of AChE activity. Though ATCh is a popular substrate, it has certain drawbacks as well. Because of these limitations, there is a need for the development of reliable and rapid assays for determination of AChE activity in cases of OP poisoning. In the present work, we have used 1-Naphthyl acetate (1-NA) as a fluorogenic substrate for the estimation of AChE activity of human erythrocytes. It is well known that due to inter-individual variation in AChE activity, the baseline value cannot be correctly predicted. Therefore, using 1-NA, we have developed a rapid, sensitive and baseline free assay for the estimation of AChE activity. The assay is based on reactivation and fluorescence quenching using a cocktail of oximes for the determination of cholinesterase activity in a post-exposure sample. Moreover, it is free from interference due to oximolysis which is an established limitation of ATCh. We feel that such an assay using 1-NA has the potential to be explored at the point of care for rapid detection of OP poisoning.
Could glucagon-like peptide-1 be a potential biomarker of early-stage intestinal ischemia? Biochimie (IF 3.188) Pub Date : 2018-11-14 Lorène J. Lebrun, Jacques Grober
Intestinal ischemia, also called mesenteric ischemia, is a severe gastrointestinal and vascular medical emergency caused by a sudden decrease of blood flow through the mesenteric vessels. It generates hypoperfusion of intestinal tissues and can rapidly progress to intestinal wall infarction, systemic inflammation or even death if not treated in time. The mortality of this condition is still considerably high despite all the medical advances of the past few years. This is partially due to the difficulty of diagnosing early stage mesenteric ischemia. Indeed, a speedy and correct diagnosis is decisive for suitable medical care. However, early symptoms are unspecific and conventional clinical markers are neither specific nor sensitive enough. In the last few years, significant clinical and preclinical efforts have been made to find biomarkers which could predict gastrointestinal damage before it becomes irreversible. Here, the gut-derived hormone glucagon-like peptide-1 (GLP-1) is described as a potential early biomarker of this severe condition. Indeed, GLP-1 plasma levels rise rapidly in both mice and humans with intestinal ischemia. This discovery could counter the cruel lack of clinical biomarkers available to diagnose and therefore manage intestinal ischemia efficiently in the early stages. GLP-1 could thus become part of a panel of biomarkers for intestinal ischemia and could help to reduce the associated high mortality rates.
Serotonin in retina Biochimie (IF 3.188) Pub Date : 2018-11-09 Justine Masson
The expression of serotonin (5-HT) in the retina was first reported in the sixties. The detection of vesicular monoamine transporter and serotonin receptors in several retinal cells confirm that 5-HT is playing a neuromodulatory role in this structure. Whereas signaling pathways activated by 5-HT receptor binding has been poorly investigated so far, numerous data demonstrated that 5-HT is involved in retinal physiology, retinal physiopathology and photoreceptor survival.
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 Michel Guichardant, Evelyne Véricel, Michel 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.
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.
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.
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.
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.
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.
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 (NLRP, TLR, RAGE, respectively), pentraxins and complement systems. We discuss role of fatty acids and lipoproteins in the degeneration of RPE and development of AMD.
Experimental human endotoxemia as a model of systemic inflammation Biochimie (IF 3.188) Pub Date : 2018-06-22 Dirk van Lier, Christopher Geven, Guus P. Leijte, Peter Pickkers
Systemic inflammation plays a pivotal role in a multitude of conditions, including sepsis, trauma, major surgery and burns. However, comprehensive analysis of the pathophysiology underlying this systemic inflammatory response is greatly complicated by variations in the immune response observed in critically ill patients, which is a result of inter-individual differences in comorbidity, comedication, source of infection, causative pathogen, and onset of the inflammatory response. During experimental human endotoxemia, human subjects are challenged with purified endotoxin (lipopolysaccharide) intravenously which induces a short-lived, well-tolerated and controlled systemic inflammatory response, similar to that observed during sepsis. The human endotoxemia model can be conducted in a highly standardized and reproducible manner, using a carefully selected homogenous study population. As such, the experimental human endotoxemia model does not share the aforementioned clinical limitations and enables us to investigate both the mechanisms of systemic inflammation, as well as to evaluate novel (pharmacological) interventions in humans in vivo. The present review provides a detailed overview of the various designs, organ-specific changes, and strengths and limitations of the experimental human endotoxemia model, with the main focus on its use as a translational model for sepsis research.
A cross-talk between fat and bitter taste modalities Biochimie (IF 3.188) Pub Date : 2018-06-22 Amira S. Khan, Babar Murtaza, Aziz Hichami, Naim A. Khan
The choice of food is governed largely by the sense of taste. To date, five basic taste modalities have been described; however, there is an increasing agreement on the existence of a 6th fat taste. The taste modalities might interact with each other and also with other senses. The advancements in cellular and molecular biology have helped the characterization of taste signaling mechanisms, down to the receptor level and beyond. CD36 and GPR120 have been shown to be involved in the detection of fat taste while bitter taste is perceived by a number of receptors that belong to a family of taste-type 2 receptors (T2R or TAS2R). Hence, the most common role is played by TAS2R16 and TAS2R38 in bitter taste perception in humans. Increasing evidences from behavioural studies suggest that fat and bitter taste modalities might interact with each other, and this interaction might be critical in obesity. In the current review, we will discuss the evidence from genetic and behavioural studies and propose the molecular mechanism of a cross-talk between fat and bitter tastes.
Serotonin and human cancer: A critical view Biochimie (IF 3.188) Pub Date : 2018-06-21 Denis Sarrouilhe, Marc Mesnil
Besides its classical functions as a neurotransmitter in the central nervous system, local mediator in the gastrointestinal tract and vasoactive agent in the blood, serotonin has more recently emerged as a growth factor for human tumor cells of different origins (carcinomas, glioma and carcinoids). Several data are also available on serotonin involvement in cancer cell migration, metastatic dissemination and tumor angiogenesis. The serotonin-induced signaling pathways that promote tumor progression are complex and only partly understood in some cancer types. The results of several studies showed that serotonin levels in the tumor played a crucial role in cancer progression. A serotonin production and secretion by neuroendocrine cells have been shown in the progression of several solid tumors and the involvement of a serotoninergic autocrine loop was proposed. Specific receptor subtypes are associated with different fundamental stages of tumor progression and the pattern of receptors expression becomes dysregulated in several human tumors when compared with normal cells or tissues. Serotonin receptors, selective serotonin transporter and serotonin synthesis pathways are potential chemotherapeutic targets for the treatment of several cancers in which therapeutic approaches are limited. Through several asked questions, this critical mini-review discusses the relevance of the involvement of serotonin in human cancer progression.
Serotonin in the gut: Blessing or a curse Biochimie (IF 3.188) Pub Date : 2018-06-14 Suhrid Banskota, Jean-Eric Ghia, Waliul I. Khan
Serotonin (5-hydroxytryptamine or 5-HT) once most extensively studied as a neurotransmitter of the central nervous system, is seen to be predominantly secreted in the gut. About 95% of 5-HT is estimated to be found in gut mainly within the enterochromaffin cells whereas about 5% is found in the brain. 5-HT is an important enteric signaling molecule and is well known for playing a key role in sensory-motor and secretory functions in the gut. In recent times, studies uncovering various new functions of gut-derived 5-HT indicate that many more are yet to be discovered in coming days. Recent studies revealed that 5-HT plays a pivotal role in immune cell activation and generation/perpetuation of inflammation in the gut. In addition to its various roles in the gut, there are now emerging evidences that suggest an important role of gut-derived 5-HT in other biological processes beyond the gut, such as bone remodeling and metabolic homeostasis. This review focuses to briefly summarize the accumulated and newly updated role of 5-HT in the maintenance of normal gut physiology and in the pathogenesis of inflammation in the gut. The collected information about this multifaceted signaling molecule may aid in distinguishing its good and bad effects which may lead to the development of novel strategies to overcome the unwanted effect, such as in inflammatory bowel disease.
Strategies in the design of endosomolytic agents for facilitating endosomal escape in nanoparticles Biochimie (IF 3.188) Pub Date : 2019-02-21 Aqeel Ahmad, Javed Masood Khan, Shafiul Haque
Nanoparticles (NPs) are one of the leading and promising technologies for gene and drug delivery. However, despite continuous advancements in the delivery of NPs, endosomal escape remains a major issue and a matter of grave concern for developing an efficient and targeted delivery system for therapeutic applications. Most of NPs generally follow endocytic pathway for internalization into the cells. Following the internalization process, NPs must escape into the cell cytoplasm for evading degradation by hydrolytic enzymes present in the lysosomes. Various types of lipids have been used in the past viz. fusogenic lipid dioleoylphosphatidylethanolamine (DOPE), pH-sensitive lipids, cationic lipid and multiple charges containing lipid to escape from endosomes. Recently, several novel polymers, pH-sensitive peptides, proteins and many others endosomolytic agents have been identified and developed for incorporating into gene and drug delivery system to facilitate endosomal escape. In this review, endosomal escape mechanisms of different types of NPs have been discussed in detail and compared with endosomal escape mechanisms of viruses and other synthetic gene delivery systems to escape from endosomes. Also, the designing of endosomolytic agents to facilitate endosomal escape based on different approaches and strategies is explored. Moreover, this review article highlights the recent advancements in the development of NPs equipped with endosomolytic agents including its future directions and applications in the field of nanomedicine.
Nybomycin-producing Streptomyces isolated from carpenter ant Camponotus vagus Biochimie (IF 3.188) Pub Date : 2019-02-21 Yuliya V. Zakalyukina, Mikhail V. Birykov, Dmitrii A. Lukianov, Dmitrii I. Shiriaev, Ekaterina S. Komarova, Dmitry A. Skvortsov, Yury Kostyukevich, Vadim N. Tashlitsky, Vladimir I. Polshakov, Eugene Nikolaev, Petr V. Sergiev, Ilya A. Osterman
A novel strain of Actinomycetes was isolated from the body of an ant (Camponotus vagus Scopoli) and its genetic and morphological properties were characterized. The 16S rDNA gene sequence analysis of the isolate revealed its high phylogenetic relationship with type strains of Streptomyces violaceochromogenes NBRC 13100T. As a result of antimicrobial activity assessment, it was found that the fermentation broth of the isolated strain both inhibited the growth and induced the SOS response in E. coli BW25113 ΔtolC strain cells. Using bioassay-guided fractionation, mass spectrometric and NMR analyses we identified the active compound to be nybomycin, a previously described antibiotic. Here we report for the first time Streptomyces producer of nybomycin in association with carpenter ants and demonstrate cytotoxic activity of nybomycin against human cell lines.
L-Dopa decarboxylase interaction with the major signaling regulator ΡΙ3Κ in tissues and cells of neural and peripheral origin Biochimie (IF 3.188) Pub Date : 2019-02-20 Alice G. Vassiliou, Maria-Zacharenia Siaterli, Efseveia Frakolaki, Panayiota Gkogkosi, Ioannis Paspaltsis, Theodoros Sklaviadis, Dido Vassilacopoulou, Niki Vassilaki
L-Dopa decarboxylase (DDC) catalyzes the decarboxylation of L-Dopa to dopamine and 5-hydroxytryptophan (5-HTP) to serotonin. Although DDC has been purified from a variety of peripheral organs, including the liver, kidney and pancreas, the physiological significance of the peripherally expressed enzyme is not yet fully understood. DDC has been considered as a potential novel biomarker for various types of cancer, however, the role of DDC in the development of hepatocellular carcinoma (HCC) remains to be evaluated. Phosphatidylinositol 3-kinase (PI3K), on the other hand, has been shown to play a key role in the tumorigenesis, proliferation, metastasis, apoptosis, and angiogenesis of HCC by regulating gene expression. We initially identified the interaction of DDC with PI3K by means of the phage display methodology. This association was further confirmed in human hepatocellular carcinoma cell lines, human embryonic kidney cells, human neuroblastoma cells, as well as mouse brain, by the use of specific antibodies raised against DDC and PI3K. Functional aspects of the above interaction were studied upon treatment with the DDC inhibitor, carbidopa, and the PI3K inhibitor, LY294002. Interestingly, our data demonstrate the expression of neuronal type DDC mRNA in HCC cells. The present investigation provides new evidence on the possible link of DDC with the PI3K pathway, underlining the biological significance of this complex enzyme.
Brain-derived neurotrophic factor induces thioredoxin-1 expression through TrkB/Akt/CREB pathway in SH-SY5Y cells Biochimie (IF 3.188) Pub Date : 2019-02-20 Liping Bai, Se Zhang, Xiaoshuang Zhou, Ye Li, Jie Bai
Brain-derived neurotrophic factor (BDNF) is one of the neurotrophic factors that are vital to the survival and proliferation of neuron. Thioredoxin-1 (Trx-1) is a redox regulating protein and plays various roles in regulating transcript factors and inhibiting apoptosis. It has been reported that Trx-1 is required for nerve growth factor-mediated signal transduction and neurite outgrowth, and is involved in synaptic protein expression induced by BDNF. However, the molecular mechanism on BDNF inducing Trx-1 expression has not been fully verified. The present study investigated the expression of Trx-1 after treatment with BDNF in SH-SY5Y cells. We first demonstrated that cell viability and the expression of Trx-1 were increased by BDNF in SH-SY5Y cells, which were inhibited by the tyrosine kinase B (TrkB) inhibitor, K252a, and the phosphatidylinositol 3-kinase (PI3-K) inhibitor, LY294002. Moreover, BDNF increased the activity of cAMP response element-binding protein (CREB) through TrkB/PI3-K/Akt pathway. Whereas the expression of Trx-1 induced by BDNF was suppressed by CREB siRNA. Thus, our data suggest that BDNF induces the expression of Trx-1 through the TrkB/Akt/CREB pathway.
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