International Journal of Cell Biology The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Impact of Hybrid and Complex N-Glycans on Cell Surface Targeting of the Endogenous Chloride Cotransporter Slc12a2 Mon, 17 Aug 2015 13:56:41 +0000 The Na+K+2Cl− cotransporter-1 (Slc12a2, NKCC1) is widely distributed and involved in cell volume/ion regulation. Functional NKCC1 locates in the plasma membrane of all cells studied, particularly in the basolateral membrane of most polarized cells. Although the mechanisms involved in plasma membrane sorting of NKCC1 are poorly understood, it is assumed that N-glycosylation is necessary. Here, we characterize expression, N-glycosylation, and distribution of NKCC1 in COS7 cells. We show that ~25% of NKCC1 is complex N-glycosylated whereas the rest of it corresponds to core/high-mannose and hybrid-type N-glycosylated forms. Further, ~10% of NKCC1 reaches the plasma membrane, mostly as core/high-mannose type, whereas ~90% of NKCC1 is distributed in defined intracellular compartments. In addition, inhibition of the first step of N-glycan biosynthesis with tunicamycin decreases total and plasma membrane located NKCC1 resulting in almost undetectable cotransport function. Moreover, inhibition of N-glycan maturation with swainsonine or kifunensine increased core/hybrid-type NKCC1 expression but eliminated plasma membrane complex N-glycosylated NKCC1 and transport function. Together, these results suggest that (i) NKCC1 is delivered to the plasma membrane of COS7 cells independently of its N-glycan nature, (ii) most of NKCC1 in the plasma membrane is core/hybrid-type N-glycosylated, and (iii) the minimal proportion of complex N-glycosylated NKCC1 is functionally active. Richa Singh, Mohammed Mashari Almutairi, Romario Pacheco-Andrade, Mohamed Y. Mahmoud Almiahuob, and Mauricio Di Fulvio Copyright © 2015 Richa Singh et al. All rights reserved. Intermittent Compressive Stress Enhanced Insulin-Like Growth Factor-1 Expression in Human Periodontal Ligament Cells Thu, 28 May 2015 07:40:48 +0000 Mechanical force was shown to promote IGF-1 expression in periodontal ligament both in vitro and in vivo. Though the mechanism of this effect has not yet been proved, here we investigated the molecular mechanism of intermittent mechanical stress on IGF-1 expression. In addition, the role of hypoxia on the intermittent compressive stress on IGF-1 expression was also examined. In this study, human periodontal ligament cells (HPDLs) were stimulated with intermittent mechanical stress for 24 hours. IGF-1 expression was examined by real-time polymerase chain reaction. Chemical inhibitors were used to determine molecular mechanisms of these effects. For hypoxic mimic condition, the CoCl2 supplementation was employed. The results showed that intermittent mechanical stress dramatically increased IGF-1 expression at 24 h. The pretreatment with TGF-β receptor I or TGF-β1 antibody could inhibit the intermittent mechanical stress-induced IGF-1 expression. Moreover, the upregulation of TGF-β1 proteins was detected in intermittent mechanical stress treated group. Correspondingly, the IGF-1 expression was upregulated upon being treated with recombinant human TGF-β1. Further, the hypoxic mimic condition attenuated the intermittent mechanical stress and rhTGF-β1-induced IGF-1 expression. In summary, this study suggests intermittent mechanical stress-induced IGF-1 expression in HPDLs through TGF-β1 and this phenomenon could be inhibited in hypoxic mimic condition. Jittima Pumklin, Jeeranan Manokawinchoke, Kanokporn Bhalang, and Prasit Pavasant Copyright © 2015 Jittima Pumklin et al. All rights reserved. The Role of Hyaluronan in Innate Defense Responses of the Intestine Mon, 30 Mar 2015 08:05:41 +0000 Hyaluronan is an abundant extracellular matrix component prevalent in the vertebrate intestinal tract. Here we discuss what is known about hyaluronan distribution during homeostasis and inflammatory diseases of the gut and discuss ways in which this glycosaminoglycan can participate in regulating innate host defense mechanisms. These natural responses include mechanisms promoting rapid leukocyte recruitment after bacterial challenge/colon tissue damage as well as promoting epithelial defense mechanisms in the intestine. Carol A. de la Motte and Sean P. Kessler Copyright © 2015 Carol A. de la Motte and Sean P. Kessler. All rights reserved. HARE-Mediated Endocytosis of Hyaluronan and Heparin Is Targeted by Different Subsets of Three Endocytic Motifs Wed, 25 Mar 2015 06:59:36 +0000 The hyaluronan (HA) receptor for endocytosis (HARE) is a multifunctional recycling clearance receptor for 14 different ligands, including HA and heparin (Hep), which bind to discrete nonoverlapping sites. Four different functional endocytic motifs (M) in the cytoplasmic domain (CD) target coated pit mediated uptake: (YSYFRI2485 (M1), FQHF2495 (M2), NPLY2519 (M3), and DPF2534 (M4)). We previously found (Pandey et al. J. Biol. Chem. 283, 21453, 2008) that M1, M2, and M3 mediate endocytosis of HA. Here we assessed the ability of HARE variants with a single-motif deletion or containing only a single motif to endocytose HA or Hep. Single-motif deletion variants lacking M1, M3, or M4 (a different subset than involved in HA uptake) showed decreased Hep endocytosis, although M3 was the most active; the remaining redundant motifs did not compensate for loss of other motifs. Surprisingly, a HARE CD variant with only M3 internalized both HA and Hep, whereas variants with either M2 or M4 alone did not endocytose either ligand. Internalization of HA and Hep by HARE CD mutants was dynamin-dependent and was inhibited by hyperosmolarity, confirming clathrin-mediated endocytosis. The results indicate a complicated relationship among multiple CD motifs that target coated pit uptake and a more fundamental role for motif M3. Madhu S. Pandey, Edward N. Harris, and Paul H. Weigel Copyright © 2015 Madhu S. Pandey et al. All rights reserved. Effect of Serum and Oxygen Concentration on Gene Expression and Secretion of Paracrine Factors by Mesenchymal Stem Cells Mon, 29 Dec 2014 00:10:21 +0000 Mesenchymal stem cells (MSC) secrete paracrine factors that may exert a protective effect on the heart after coronary artery occlusion. This study was done to determine the effect of hypoxia and serum levels on the mRNA expression and secretion of paracrine factors. Mouse bone marrow MSC were cultured with 5% or 20% serum and in either normoxic (21% O2) or hypoxic (1% O2) conditions. Expression of mRNA for vascular endothelial growth factor (VEGF), monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein-1α (MIP-1α), MIP-1β, and matrix metalloproteinase-2 (MMP-2) was determined by RT-qPCR. Secretion into the culture media was determined by ELISA. Hypoxia caused a reduction in gene expression for MCP-1 and an increase for VEGF (5% serum), MIP-1α, MIP-1β, and MMP-2. Serum reduction lowered gene expression for VEGF (normoxia), MCP-1 (hypoxia), MIP-1α (hypoxia), MIP-1β (hypoxia), and MMP-2 (hypoxia) and increased gene expression for MMP-2 (normoxia). The level of secretion of these factors into the media generally paralleled gene expression with some exceptions. These data demonstrate that serum and oxygen levels have a significant effect on the gene expression and secretion of paracrine factors by MSC which will affect how MSC interact in vivo during myocardial ischemia. Patrick Page, Joshua DeJong, Alaina Bandstra, and Robert A. Boomsma Copyright © 2014 Patrick Page et al. All rights reserved. CXCL12 Modulates Prostate Cancer Cell Adhesion by Altering the Levels or Activities of β1-Containing Integrins Mon, 15 Dec 2014 07:38:05 +0000 The mechanisms by which prostate cancer (PCa) cell adhesion and migration are controlled during metastasis are not well understood. Here, we studied the effect of CXCL12 in PCa cell adhesion and spreading in DU145 and PC3 cell lines using as substrates collagen I, fibronectin (FN), and their recombinant fragments. CXCL12 treatment increased β1 integrin-dependent PC3 cell adhesion on FN which correlated with increased focal adhesion kinase activation. However neither α5β1 nor α4β1 subunits were involved in this adhesion. By contrast, CXCL12 decreased DU145 adhesion and spreading on FN by downregulating α5 and β1 integrin expression. To demonstrate the clinical relevance of CXCL12 in PCa, we measured CXCL12 levels in plasma by using ELISA and found that the chemokine is elevated in PCa patients when compared to controls. The high concentration of CXCL12 in patients suffering from PCa in comparison to those with benign disease or healthy individuals implicates CXCL12 as a potential biomarker for PCa. In addition these data show that CXCL12 may be crucial in controlling PCa cell adhesion on fibronectin and collagen I, possibly via crosstalk with integrin receptors and/or altering the expression levels of integrin subunits. Mehdi Dehghani, Sedigheh Kianpour, Ana Zangeneh, and Zohreh Mostafavi-Pour Copyright © 2014 Mehdi Dehghani et al. All rights reserved. Assessment of the Potential of CDK2 Inhibitor NU6140 to Influence the Expression of Pluripotency Markers NANOG, OCT4, and SOX2 in 2102Ep and H9 Cells Mon, 17 Nov 2014 06:27:08 +0000 As cyclin-dependent kinases (CDKs) regulate cell cycle progression and RNA transcription, CDKs are attractive targets for creating cancer cell treatments. In this study we investigated the effects of the small molecular agent NU6140 (inhibits CDK2 and cyclin A interaction) on human embryonic stem (hES) cells and embryonal carcinoma-derived (hEC) cells via the expression of transcription factors responsible for pluripotency. A multiparameter flow cytometric method was used to follow changes in the expression of NANOG, OCT4, and SOX2 together in single cells. Both hES and hEC cells responded to NU6140 treatment by induced apoptosis and a decreased expression of NANOG, OCT4, and SOX2 in surviving cells. A higher sensitivity to NU6140 application in hES than hEC cells was detected. NU6140 treatment arrested hES and hEC cells in the G2 phase and inhibited entry into the M phase as evidenced by no significant increase in histone 3 phosphorylation. When embryoid bodies (EBs) formed from NU6104 treated hES cells were compared to EBs from untreated hES cells differences in ectodermal, endodermal, and mesodermal lineages were found. The results of this study highlight the importance of CDK2 activity in maintaining pluripotency of hES and hEC cells and in differentiation of hES cells. Ade Kallas, Martin Pook, Annika Trei, and Toivo Maimets Copyright © 2014 Ade Kallas et al. All rights reserved. p38δ MAPK: Emerging Roles of a Neglected Isoform Wed, 17 Sep 2014 07:52:27 +0000 p38δ mitogen activated protein kinase (MAPK) is a unique stress responsive protein kinase. While the p38 MAPK family as a whole has been implicated in a wide variety of biological processes, a specific role for p38δ MAPK in cellular signalling and its contribution to both physiological and pathological conditions are presently lacking. Recent emerging evidence, however, provides some insights into specific p38δ MAPK signalling. Importantly, these studies have helped to highlight functional similarities as well as differences between p38δ MAPK and the other members of the p38 MAPK family of kinases. In this review we discuss the current understanding of the molecular mechanisms underlying p38δ MAPK activity. We outline a role for p38δ MAPK in important cellular processes such as differentiation and apoptosis as well as pathological conditions such as neurodegenerative disorders, diabetes, and inflammatory disease. Interestingly, disparate roles for p38δ MAPK in tumour development have also recently been reported. Thus, we consider evidence which characterises p38δ MAPK as both a tumour promoter and a tumour suppressor. In summary, while our knowledge of p38δ MAPK has progressed somewhat since its identification in 1997, our understanding of this particular isoform in many cellular processes still strikingly lags behind that of its counterparts. Carol O’Callaghan, Liam J. Fanning, and Orla P. Barry Copyright © 2014 Carol O’Callaghan et al. All rights reserved. Matrix Gla Protein Binds to Fibronectin and Enhances Cell Attachment and Spreading on Fibronectin Thu, 21 Aug 2014 09:41:31 +0000 Background. Matrix Gla protein (MGP) is a vitamin K-dependent, extracellular matrix protein. MGP is a calcification inhibitor of arteries and cartilage. However MGP is synthesized in many tissues and is especially enriched in embryonic tissues and in cancer cells. The presence of MGP in those instances does not correlate well with the calcification inhibitory role. This study explores a potential mechanism for MGP to bind to matrix proteins and alter cell matrix interactions. Methods. To determine whether MGP influences cell behavior through interaction with fibronectin, we studied MGP binding to fibronectin, the effect of MGP on fibronectin mediated cell attachment and spreading and immunolocalized MGP and fibronectin. Results. First, MGP binds to fibronectin. The binding site for MGP is in a specific fibronectin fragment, called III1-C or anastellin. The binding site for fibronectin is in a MGP C-terminal peptide comprising amino acids 61–77. Second, MGP enhances cell attachment and cell spreading on fibronectin. MGP alone does not promote cell adhesion. Third, MGP is present in fibronectin-rich regions of tissue sections. Conclusions. MGP binds to fibronectin. The presence of MGP increased cell-fibronectin interactions. Satoru Ken Nishimoto and Miyako Nishimoto Copyright © 2014 Satoru Ken Nishimoto and Miyako Nishimoto. All rights reserved. Emerging Lung Cancer Therapeutic Targets Based on the Pathogenesis of Bone Metastases Thu, 14 Aug 2014 00:00:00 +0000 Lung cancer is the second most common cancer and the leading cause of cancer related mortality in both men and women. Each year, more people die of lung cancer than of colon, breast, and prostate cancers combined. It is widely accepted that tumor metastasis is a formidable barrier to effective treatment of lung cancer. The bone is one of the frequent metastatic sites for lung cancer occurring in a large number of patients. Bone metastases can cause a wide range of symptoms that could impair quality of life of lung cancer patients and shorten their survival. We strongly believe that molecular targets (tumor-related and bone microenvironment based) that have been implicated in lung cancer bone metastases hold great promise in lung cancer therapeutics. Thus, this paper discusses some of the emerging molecular targets that have provided insights into the cascade of metastases in lung cancer with the focus on bone invasion. It is anticipated that the information gathered might be useful in future efforts of optimizing lung cancer treatment strategies. Moses O. Oyewumi, Adnan Alazizi, Daniel Wehrung, Rami Manochakian, and Fayez F. Safadi Copyright © 2014 Moses O. Oyewumi et al. All rights reserved. Effect of Allium cepa L. on Lipopolysaccharide-Stimulated Osteoclast Precursor Cell Viability, Count, and Morphology Using 4′,6-Diamidino-2-phenylindole-Staining Sun, 03 Aug 2014 11:27:50 +0000 Allium cepa L. is known to possess numerous pharmacological properties. Our aim was to examine the in vitro effects of Allium cepa L. extract (AcE) on Porphyromonas gingivalis LPS and Escherichia coli LPS-stimulated osteoclast precursor cells to determine cell viability to other future cell-based assays. Osteoclast precursor cells (RAW 264.7) were stimulated by Pg LPS (1 μg/mL) and E. coli LPS (1 μg/mL) in the presence or absence of different concentrations of AcE (10–1000 μg/mL) for 5 days at 37°C/5% CO2. Resazurin reduction and total protein content assays were used to detect cell viability. AcE did not affect cell viability. Resazurin reduction assay showed that AcE, at up to 1000 μg/mL, did not significantly affect cell viability and cellular protein levels. Additionally a caspase 3/7 luminescence assay was used to disclose apoptosis and there was no difference in apoptotic activity between tested groups and control group. Fluorescence images stained by DAPI showed no alteration on the morphology and cell counts of LPS-stimulated osteoclast precursor cells with the use of AcE in all tested concentrations when compared to control. These findings suggest that Allium cepa L. extract could be used for in vitro studies on Porphyromonas gingivalis LPS and Escherichia coli LPS-stimulated osteoclast precursor cells. Tatiane Oliveira, Camila A. Figueiredo, Carlos Brito, Alexander Stavroullakis, Anuradha Prakki, Eudes Da Silva Velozo, and Getulio Nogueira-Filho Copyright © 2014 Tatiane Oliveira et al. All rights reserved. Cell Death Sun, 11 May 2014 13:27:43 +0000 Claudia Giampietri, Alessio Paone, and Alessio D’Alessio Copyright © 2014 Claudia Giampietri et al. All rights reserved. RNA Viruses: ROS-Mediated Cell Death Thu, 08 May 2014 15:43:19 +0000 Reactive oxygen species (ROS) are well known for being both beneficial and deleterious. The main thrust of this review is to investigate the role of ROS in ribonucleic acid (RNA) virus pathogenesis. Much evidences has accumulated over the past decade, suggesting that patients infected with RNA viruses are under chronic oxidative stress. Changes to the body’s antioxidant defense system, in relation to SOD, ascorbic acid, selenium, carotenoids, and glutathione, have been reported in various tissues of RNA-virus infected patients. This review focuses on RNA viruses and retroviruses, giving particular attention to the human influenza virus, Hepatitis c virus (HCV), human immunodeficiency virus (HIV), and the aquatic Betanodavirus. Oxidative stress via RNA virus infections can contribute to several aspects of viral disease pathogenesis including apoptosis, loss of immune function, viral replication, inflammatory response, and loss of body weight. We focus on how ROS production is correlated with host cell death. Moreover, ROS may play an important role as a signal molecule in the regulation of viral replication and organelle function, potentially providing new insights in the prevention and treatment of RNA viruses and retrovirus infections. Mohammad Latif Reshi, Yi-Che Su, and Jiann-Ruey Hong Copyright © 2014 Mohammad Latif Reshi et al. All rights reserved. Protein Misfolding and Neurodegenerative Diseases Mon, 31 Mar 2014 11:24:12 +0000 Alessio Cardinale, Roberto Chiesa, and Michael Sierks Copyright © 2014 Alessio Cardinale et al. All rights reserved. Small G Proteins Dexras1 and RHES and Their Role in Pathophysiological Processes Thu, 20 Mar 2014 11:58:15 +0000 Dexras1 and RHES, monomeric G proteins, are members of small GTPase family that are involved in modulation of pathophysiological processes. Dexras1 and RHES levels are modulated by hormones and Dexras1 expression undergoes circadian fluctuations. Both these GTPases are capable of modulating calcium ion channels which in turn can potentially modulate neurosecretion/hormonal release. These two GTPases have been reported to prevent the aberrant cell growth and induce apoptosis in cell lines. Present review focuses on role of these two monomeric GTPases and summarizes their role in pathophysiological processes. Ashish Thapliyal, Rashmi Verma, and Navin Kumar Copyright © 2014 Ashish Thapliyal et al. All rights reserved. Necrostatin-1 Reduces Neurovascular Injury after Intracerebral Hemorrhage Thu, 06 Mar 2014 11:22:15 +0000 Intracerebral hemorrhage (ICH) is the most common form of hemorrhagic stroke, accounting for 15% of all strokes. ICH has the highest acute mortality and the worst long-term prognosis of all stroke subtypes. Unfortunately, the dearth of clinically effective treatment options makes ICH the least treatable form of stroke, emphasizing the need for novel therapeutic targets. Recent work by our laboratory identified a novel role for the necroptosis inhibitor, necrostatin-1, in limiting neurovascular injury in tissue culture models of hemorrhagic injury. In the present study, we tested the hypothesis that necrostatin-1 reduces neurovascular injury after collagenase-induced ICH in mice. Necrostatin-1 significantly reduced hematoma volume by 54% at 72 h after-ICH, as compared to either sham-injured mice or mice administered an inactive, structural analogue of necrostatin-1. Necrostatin-1 also limited cell death by 48%, reduced blood-brain barrier opening by 51%, attenuated edema development to sham levels, and improved neurobehavioral outcomes after ICH. These data suggest a potential clinical utility for necrostatin-1 and/or novel necroptosis inhibitors as an adjunct therapy to reduce neurological injury and improve patient outcomes after ICH. Melanie D. King, Wittstatt A. Whitaker-Lea, James M. Campbell, Cargill H. Alleyne Jr., and Krishnan M. Dhandapani Copyright © 2014 Melanie D. King et al. All rights reserved. Changes in the Distribution of the α3 Na+/K+ ATPase Subunit in Heterozygous Lurcher Purkinje Cells as a Genetic Model of Chronic Depolarization during Development Thu, 27 Feb 2014 12:24:04 +0000 A common assumption of excitotoxic mechanisms in the nervous system is that the ionic imbalance resulting from overstimulation of glutamate receptors and increased Na+ and Ca++ influx overwhelms cellular energy metabolic systems leading to cell death. The goal of this study was to examine how a chronic Na+ channel leak current in developing Purkinje cells in the heterozygous Lurcher mutant (+/Lc) affects the expression and distribution of the α3 subunit of the Na+/K+ ATPase pump, a key component of the homeostasis system that maintains ionic equilibrium in neurons. The expression pattern of the catalytic α3 Na+/K+ ATPase subunit was analyzed by immunohistochemistry, histochemistry, and Western Blots in wild type (WT) and +/Lc cerebella at postnatal days P10, P15, and P25 to determine if there are changes in the distribution of active Na+/K+ ATPase subunits in degenerating Purkinje cells. The results suggest that the expression of the catalytic α3 subunit is altered in chronically depolarized +/Lc Purkinje cells, although the density of active Na+/K+ ATPase pumps is not significantly altered compared with WT in the cerebellar cortex at P15, and then declines from P15 to P25 in the +/Lc cerebellum as the +/Lc Purkinje cells degenerate. Rebecca McFarland, Hadi S. Zanjani, Jean Mariani, and Michael W. Vogel Copyright © 2014 Rebecca McFarland et al. All rights reserved. The Linker Histone H1.2 Is an Intermediate in the Apoptotic Response to Cytokine Deprivation in T-Effectors Thu, 13 Feb 2014 13:12:46 +0000 Tissue homeostasis is a dynamic process involving proliferation and the removal of redundant or damaged cells. This is exemplified in the coordinated deletion—triggered by limiting trophic factors/cytokines in the extracellular milieu—of differentiated T cells overproduced during the mammalian immune response. However, mechanisms by which extracellular cues are perceived and transduced as apoptotic triggers remain incompletely understood. T-effectors are dependent on cytokines for survival and undergo apoptosis following cytokine withdrawal. Here we report that leptomycin B (LMB), an inhibitor of nuclear export machinery, protected T-effectors from apoptosis implicating a nuclear intermediate in the apoptotic pathway. Evidence is presented that the linker histone H1.2 localizes to the cytoplasm, by a mechanism sensitive to regulation by LMB, to activate apoptotic signaling culminating in nuclear and mitochondrial damage in T-effectors in response to cytokine deprivation. H1.2 is detected in a complex with the proapoptotic mitochondrial resident Bak and its subcellular localization regulated by Jun-N-terminal kinase (JNK), an intermediate in the apoptotic cascade in T-effectors. These data suggest that metabolic stressors may impinge on H1.2 dynamics favoring its activity at the mitochondrion, thereby functioning as a molecular switch for T-effector apoptosis. Megha Garg, Lakshmi R. Perumalsamy, G. V. Shivashankar, and Apurva Sarin Copyright © 2014 Megha Garg et al. All rights reserved. Mitochondrial DNA and Functional Investigations into the Radiosensitivity of Four Mouse Strains Wed, 12 Feb 2014 11:16:24 +0000 We investigated whether genetic radiosensitivity-related changes in mtDNA/nDNA ratios are significant to mitochondrial function and if a material effect on mtDNA content and function exists. BALB/c (radiosensitive), C57BL/6 (radioresistant), and F1 hybrid mouse strains were exposed to total body irradiation. Hepatic genomic DNA was extracted, and mitochondria were isolated. Mitochondrial oxygen consumption, ROS, and calcium-induced mitochondrial swelling were measured. Radiation influenced strain-specific survival in vivo. F1 hybrid survival was influenced by maternal input. Changes in mitochondrial content corresponded to survival in vivo among the 4 strains. Calcium-induced mitochondrial swelling was strain dependent. Isolated mitochondria from BALB/c mice were significantly more sensitive to calcium overload than mitochondria from C57BL/6 mice. Maternal input partially influenced the recovery effect of radiation on calcium-induced mitochondrial swelling in F1 hybrids; the hybrid with a radiosensitive maternal lineage exhibited a lower rate of recovery. Hybrids had a survival rate that was biased toward maternal input. mtDNA content and mitochondrial permeability transition pores (MPTP) measured in these strains before irradiation reflected a dominant input from the parent. After irradiation, the MPTP opened sooner in radiosensitive and hybrid strains, likely triggering intrinsic apoptotic pathways. These findings have important implications for translation into predictors of radiation sensitivity/resistance. Steven B. Zhang, David Maguire, Mei Zhang, Yeping Tian, Shanmin Yang, Amy Zhang, Katherine Casey-Sawicki, Deping Han, Jun Ma, Liangjie Yin, Yongson Guo, Xiaohui Wang, Chun Chen, Alexandra Litvinchuk, Zhenhuan Zhang, Steven Swarts, Sadasivan Vidyasagar, Lurong Zhang, and Paul Okunieff Copyright © 2014 Steven B. Zhang et al. All rights reserved. An Intimate Relationship between ROS and Insulin Signalling: Implications for Antioxidant Treatment of Fatty Liver Disease Wed, 12 Feb 2014 08:33:02 +0000 Oxidative stress damages multiple cellular components including DNA, lipids, and proteins and has been linked to pathological alterations in nonalcoholic fatty liver disease (NAFLD). Reactive oxygen species (ROS) emission, resulting from nutrient overload and mitochondrial dysfunction, is thought to be a principal mediator in NAFLD progression, particularly toward the development of hepatic insulin resistance. In the context of insulin signalling, ROS has a dual role, as both a facilitator and inhibitor of the insulin signalling cascade. ROS mediate these effects through redox modifications of cysteine residues affecting phosphatase enzyme activity, stress-sensitive kinases, and metabolic sensors. This review highlights the intricate relationship between redox-sensitive proteins and insulin signalling in the context of fatty liver disease, and to a larger extent, the importance of reactive oxygen species as primary signalling molecules in metabolically active cells. Aurèle Besse-Patin and Jennifer L. Estall Copyright © 2014 Aurèle Besse-Patin and Jennifer L. Estall. All rights reserved. Methyl Jasmonate: Putative Mechanisms of Action on Cancer Cells Cycle, Metabolism, and Apoptosis Thu, 06 Feb 2014 10:41:07 +0000 Methyl jasmonate (MJ), an oxylipid that induces defense-related mechanisms in plants, has been shown to be active against cancer cells both in vitro and in vivo, without affecting normal cells. Here we review most of the described MJ activities in an attempt to get an integrated view and better understanding of its multifaceted modes of action. MJ (1) arrests cell cycle, inhibiting cell growth and proliferation, (2) causes cell death through the intrinsic/extrinsic proapoptotic, p53-independent apoptotic, and nonapoptotic (necrosis) pathways, (3) detaches hexokinase from the voltage-dependent anion channel, dissociating glycolytic and mitochondrial functions, decreasing the mitochondrial membrane potential, favoring cytochrome release and ATP depletion, activating pro-apoptotic, and inactivating antiapoptotic proteins, (4) induces reactive oxygen species mediated responses, (5) stimulates MAPK-stress signaling and redifferentiation in leukemia cells, (6) inhibits overexpressed proinflammatory enzymes in cancer cells such as aldo-keto reductase 1 and 5-lipoxygenase, and (7) inhibits cell migration and shows antiangiogenic and antimetastatic activities. Finally, MJ may act as a chemosensitizer to some chemotherapics helping to overcome drug resistant. The complete lack of toxicity to normal cells and the rapidity by which MJ causes damage to cancer cells turn MJ into a promising anticancer agent that can be used alone or in combination with other agents. Italo Mario Cesari, Erika Carvalho, Mariana Figueiredo Rodrigues, Bruna dos Santos Mendonça, Nivea Dias Amôedo, and Franklin David Rumjanek Copyright © 2014 Italo Mario Cesari et al. All rights reserved. Cell Biology of Cysteine-Based Molecular Switches Thu, 06 Feb 2014 06:23:05 +0000 Christian Appenzeller-Herzog, Kenji Inaba, and Agnès Delaunay-Moisan Copyright © 2014 Christian Appenzeller-Herzog et al. All rights reserved. The Impact of Autophagy on Cell Death Modalities Tue, 04 Feb 2014 09:51:16 +0000 Autophagy represents a homeostatic cellular mechanism for the turnover of organelles and proteins, through a lysosome-dependent degradation pathway. During starvation, autophagy facilitates cell survival through the recycling of metabolic precursors. Additionally, autophagy can modulate other vital processes such as programmed cell death (e.g., apoptosis), inflammation, and adaptive immune mechanisms and thereby influence disease pathogenesis. Selective pathways can target distinct cargoes (e.g., mitochondria and proteins) for autophagic degradation. At present, the causal relationship between autophagy and various forms of regulated or nonregulated cell death remains unclear. Autophagy can occur in association with necrosis-like cell death triggered by caspase inhibition. Autophagy and apoptosis have been shown to be coincident or antagonistic, depending on experimental context, and share cross-talk between signal transduction elements. Autophagy may modulate the outcome of other regulated forms of cell death such as necroptosis. Recent advances suggest that autophagy can dampen inflammatory responses, including inflammasome-dependent caspase-1 activation and maturation of proinflammatory cytokines. Autophagy may also act as regulator of caspase-1 dependent cell death (pyroptosis). Strategies aimed at modulating autophagy may lead to therapeutic interventions for diseases in which apoptosis or other forms of regulated cell death may play a cardinal role. Stefan W. Ryter, Kenji Mizumura, and Augustine M. K. Choi Copyright © 2014 Stefan W. Ryter et al. All rights reserved. 2-Cys Peroxiredoxins: Emerging Hubs Determining Redox Dependency of Mammalian Signaling Networks Tue, 04 Feb 2014 09:34:46 +0000 Mammalian cells have a well-defined set of antioxidant enzymes, which includes superoxide dismutases, catalase, glutathione peroxidases, and peroxiredoxins. Peroxiredoxins are the most recently identified family of antioxidant enzymes that catalyze the reduction reaction of peroxides, such as H2O2. In particular, typical 2-Cys peroxiredoxins are the featured peroxidase enzymes that receive the electrons from NADPH by coupling with thioredoxin and thioredoxin reductase. These enzymes distribute throughout the cellular compartments and, therefore, are thought to be broad-range antioxidant defenders. However, recent evidence demonstrates that typical 2-Cys peroxiredoxins play key signal regulatory roles in the various signaling networks by interacting with or residing near a specific redox-sensitive molecule. These discoveries help reveal the redox signaling landscape in mammalian cells and may further provide a new paradigm of therapeutic approaches based on redox signaling. Jinah Park, Sunmi Lee, Sanghyuk Lee, and Sang Won Kang Copyright © 2014 Jinah Park et al. All rights reserved. The Mitochondrial Aminoacyl tRNA Synthetases: Genes and Syndromes Tue, 04 Feb 2014 09:25:44 +0000 Mitochondrial respiratory chain (RC) disorders are a group of genetically and clinically heterogeneous diseases. This is because protein components of the RC are encoded by both mitochondrial and nuclear genomes and are essential in all cells. In addition, the biogenesis and maintenance of mitochondria, including mitochondrial DNA (mtDNA) replication, transcription, and translation, require nuclear-encoded genes. In the past decade, a growing number of syndromes associated with dysfunction of mtDNA translation have been reported. This paper reviews the current knowledge of mutations affecting mitochondrial aminoacyl tRNAs synthetases and their role in the pathogenic mechanisms underlying the different clinical presentations. Daria Diodato, Daniele Ghezzi, and Valeria Tiranti Copyright © 2014 Daria Diodato et al. All rights reserved. Linking Peroxiredoxin and Vacuolar-ATPase Functions in Calorie Restriction-Mediated Life Span Extension Mon, 03 Feb 2014 11:56:43 +0000 Calorie restriction (CR) is an intervention extending the life spans of many organisms. The mechanisms underlying CR-dependent retardation of aging are still poorly understood. Despite mechanisms involving conserved nutrient signaling pathways proposed, few target processes that can account for CR-mediated longevity have so far been identified. Recently, both peroxiredoxins and vacuolar-ATPases were reported to control CR-mediated retardation of aging downstream of conserved nutrient signaling pathways. In this review, we focus on peroxiredoxin-mediated stress-defence and vacuolar-ATPase regulated acidification and pinpoint common denominators between the two mechanisms proposed for how CR extends life span. Both the activities of peroxiredoxins and vacuolar-ATPases are stimulated upon CR through reduced activities in conserved nutrient signaling pathways and both seem to stimulate cellular resistance to peroxide-stress. However, whereas vacuolar-ATPases have recently been suggested to control both Ras-cAMP-PKA- and TORC1-mediated nutrient signaling, neither the physiological benefits of a proposed role for peroxiredoxins in H2O2-signaling nor downstream targets regulated are known. Both peroxiredoxins and vacuolar-ATPases do, however, impinge on mitochondrial iron-metabolism and further characterization of their impact on iron homeostasis and peroxide-resistance might therefore increase our understanding of the beneficial effects of CR on aging and age-related diseases. Mikael Molin and Ayse Banu Demir Copyright © 2014 Mikael Molin and Ayse Banu Demir. All rights reserved. Characterization of NGF, trkANGFR, and p75NTR in Retina of Mice Lacking Reelin Glycoprotein Thu, 30 Jan 2014 10:28:28 +0000 Both Reelin and Nerve Growth Factor (NGF) exert crucial roles in retinal development. Retinogenesis is severely impaired in E-reeler mice, a model of Reelin deficiency showing specific Green Fluorescent Protein expression in Rod Bipolar Cells (RBCs). Since no data are available on Reelin and NGF cross-talk, NGF and / expression was investigated in retinas from E-reeler versus control mice, by confocal microscopy, Western blotting, and real time PCR analysis. A scattered increase of NGF protein was observed in the Ganglion Cell Layer and more pronounced in the Inner Nuclear Layer (INL). A selective increase of was detected in most of RBCs and in other cell subtypes of INL. On the contrary, a slight trend towards a decrease was detected for , albeit not significant. Confocal data were validated by Western blot and real time PCR. Finally, the decreased / ratio, representative of increase, significantly correlated with E-reeler versus E-control. These data indicate that NGF-/ is affected in E-reeler retina and that might represent the main NGF receptor involved in the process. This first NGF-/ characterization suggests that E-reeler might be suitable for exploring Reelin-NGF cross-talk, representing an additional information source in those pathologies characterized by retinal degeneration. Bijorn Omar Balzamino, Filippo Biamonte, Graziana Esposito, Ramona Marino, Francesca Fanelli, Flavio Keller, and Alessandra Micera Copyright © 2014 Bijorn Omar Balzamino et al. All rights reserved. S-Nitrosation and Ubiquitin-Proteasome System Interplay in Neuromuscular Disorders Thu, 30 Jan 2014 09:57:35 +0000 Protein S-nitrosation is deemed as a prototype of posttranslational modifications governing cell signaling. It takes place on specific cysteine residues that covalently incorporate a nitric oxide (NO) moiety to form S-nitrosothiol derivatives and depends on the ratio between NO produced by NO synthases and nitrosothiol removal catalyzed by denitrosating enzymes. A large number of cysteine-containing proteins are found to undergo S-nitrosation and, among them, the enzymes catalyzing ubiquitination, mainly the class of ubiquitin E3 ligases and the 20S component of the proteasome, have been reported to be redox modulated in their activity. In this review we will outline the processes regulating S-nitrosation and try to debate whether and how it affects protein ubiquitination and degradation via the proteasome. In particular, since muscle and neuronal health largely depends on the balance between protein synthesis and breakdown, here we will discuss the impact of S-nitrosation in the efficiency of protein quality control system, providing lines of evidence and speculating about its involvement in the onset and maintenance of neuromuscular dysfunctions. Salvatore Rizza, Costanza Montagna, Giuseppina Di Giacomo, Claudia Cirotti, and Giuseppe Filomeni Copyright © 2014 Salvatore Rizza et al. All rights reserved. LncRNAs: New Players in Apoptosis Control Thu, 30 Jan 2014 08:50:32 +0000 The discovery that the mammalian genome is largely transcribed and that almost half of the polyadenylated RNAs is composed of noncoding RNAs has attracted the attention of the scientific community. Growing amount of data suggests that long noncoding RNAs (lncRNAs) are a new class of regulators involved not only in physiological processes, such as imprinting and differentiation, but also in cancer progression and neurodegeneration. Apoptosis is a well regulated type of programmed cell death necessary for correct organ development and tissue homeostasis. Indeed, cancer cells often show an inhibition of the apoptotic pathways and it is now emerging that overexpression or downregulation of different lncRNAs in specific types of tumors sensitize cancer cells to apoptotic stimuli. In this review we summarize the latest studies on lncRNAs and apoptosis with major attention to those performed in cancer cells and in healthy cells upon differentiation. We discuss the new perspectives of using lncRNAs as targets of anticancer drugs. Finally, considering that lncRNA levels have been reported to have a correlation with specific cancer types, we argue the possibility of using lncRNAs as tumor biomarkers. Marianna Nicoletta Rossi and Fabrizio Antonangeli Copyright © 2014 Marianna Nicoletta Rossi and Fabrizio Antonangeli. All rights reserved. Necroptosis: Molecular Signalling and Translational Implications Thu, 23 Jan 2014 00:00:00 +0000 Necroptosis is a form of programmed necrosis whose molecular players are partially shared with apoptotic cell death. Here we summarize what is known about molecular signalling of necroptosis, particularly focusing on fine tuning of FLIP and IAP proteins in the apoptosis/necroptosis balance. We also emphasize necroptosis involvement in physiological and pathological conditions, particularly in the regulation of immune homeostasis. Claudia Giampietri, Donatella Starace, Simonetta Petrungaro, Antonio Filippini, and Elio Ziparo Copyright © 2014 Claudia Giampietri et al. All rights reserved.