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Although mesenchymal stem cells (MSCs) transplantation into the IVD (intervertebral disc) may be beneficial in inhibiting apoptosis of nucleus pulposus cells (NPCs) and alleviating IVD degeneration, the underlying mechanism of this therapeutic process has not been fully explained. The purpose of this study was to explore the protective effect of MSC-derived exosomes (MSC-exosomes) on NPC apoptosis and IVD degeneration and investigate the regulatory effect of miRNAs in MSC-exosomes and associated mechanisms for NPC apoptosis. MSC-exosomes were isolated from MSC medium, and its anti-apoptotic effect was assessed in a cell and rat model. The down-regulated miRNAs in apoptotic NPCs were identified, and their contents in MSC-exosomes were detected. The target genes of eligible miRNAs and possible downstream pathway were investigated. Purified MSC-exosomes were taken up by NPCs and suppressed NPC apoptosis. The levels of miR-21 were down-regulated in apoptotic NPCs while MSC-exosomes were enriched in miR-21. The exosomal miR-21 could be transferred into NPCs and alleviated TNF-α induced NPC apoptosis by targeting phosphatase and tensin homolog (PTEN) through phosphatidylinositol 3-kinase (PI3K)-Akt pathway. Intradiscal injection of MSC-exosomes alleviated the NPC apoptosis and IVD degeneration in the rat model. In conclusion, MSC-derived exosomes prevent NPCs from apoptotic process and alleviate IVD degeneration, at least partly, via miR-21 contained in exosomes. Exosomal miR-21 restrains PTEN and thus activates PI3K/Akt pathway in apoptotic NPCs. Our work confers a promising therapeutic strategy for IVD degeneration., (© 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.)

Background: Hypothermia is an effective method of reducing brain injury caused by a variety of neurological insults. It is aimed to elucidate whether a change in the expression of PERK‐mediated pathway proteins is an indicator of the neuroprotective effect of mild hypothermia after cerebral ischaemia/reperfusion. Methods: One hundred and ninety‐two male C57BL/6 mice were randomly divided into three groups: a sham group, a cerebral normothermic ischaemia/reperfusion (I/R) group and a cerebral hypothermic I/R group. A cerebral ischaemia model was established by ligating the bilateral common carotid artery for 15 min. Mice in the hypothermia group stayed in a cage that was set at 33°C, sprayed with a spray of 70% ethanol, and blown with two high‐speed fans. The state of neurons was assessed on micropreparations stained with haematoxylin–eosin and TUNEL. The expressions of GRP78, p‐perk, p‐eif2α, ATF4 and CHOP were measured by western blot analysis 6, 12, 24 and 72 h after reperfusion. Results: The number of surviving cells was significantly higher in the hypothermia group than in the group without hypothermia (p <.05). The GRP78 expression in the hypothermia group was statistically higher (p <.05) than in the ischaemia/reperfusion group. Optical densities of p‐perk, p‐eif2α and ATF4 in hippocampus CA1 neurons ischaemia were statistically significantly lower in the hypothermia group than in the ischaemia/reperfusion group (p <.05). The CHOP expression in the hypothermia group was statistically lower (p <.05) than in the ischaemia/reperfusion group. Conclusion: Mild hypothermia for 6 h promoted moderate neuroprotection by mediating the expression of GRP78, p‐PERK, p‐eIF2α, ATF4 and CHOP. [ABSTRACT FROM AUTHOR]

Multiple myeloma (MM) is an incurable cancer that is characterized by malignant plasma cell proliferation. Approximately 10% of all blood cancers are MM, and there is no standard curative therapy. In this work, we intended to synthesize, characterize, and assess the anticancer effects of selenium/chitosan/polyethylene glycol–carvacrol nanocomposites (SCP‐Car‐NCs) on MM U266 cells in vitro. Various characterization techniques were used to characterize the synthesized SCP‐Car‐NCs. Several in vitro free radical scavenging experiments were conducted to test the ability of synthesized SCP‐Car‐NCs to scavenge the different free radicals. The cytotoxicity of SCP‐Car‐NCs was assessed on Vero and U266 cells using the 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5 diphenyl tetrazolium bromide (MTT) assay. By using various fluorescence staining techniques, the amount of reactive oxygen species (ROS) generation, MMP, and apoptosis were measured. Using commercial test kits, the levels of oxidative stress and apoptotic biomarkers in control and treated U266 cells were assessed. The highest peak in the UV spectral analysis was found to be at 271 nm, demonstrating the development of SCP‐Car‐NCs. Fourier transform infrared analysis showed that the synthesized SCP‐Car‐NCs contained a variety of stretching and bonding. The X‐ray diffraction study confirmed the crystallinity of SCP‐Car‐NCs. The dynamic light scattering analysis showed that the SCP‐Car‐NCs had an average size of 171 nm. The different free radicals, such as the 2,2‐diphenyl‐1‐picrylhydrazyl, hydroxyl, and peroxyl radicals, were significantly scavenged by the SCP‐Car‐NCs. According to the MTT assay results, the SCP‐Car‐NCs decreased the viability of U266 cells while having no impact on the proliferation of Vero cells. The SCP‐Car‐NCs significantly boosted ROS production, decreased the MMP level, and promoted apoptosis, as evidenced by the fluorescence staining experiments. In U266 cells treated with SCP‐Car‐NCs, the level of thiobarbituric acid reactive substances increased while superoxide dismutases and glutathione levels were reduced. In the SCP‐Car‐NCs treated U266 cells, it was found that the Bax, caspase‐3, and −9 activities had increased while the Bcl‐2 level had decreased. In conclusion, our findings show that SCP‐Car‐NCs treatment reduced the viability and increased apoptosis in the U266 cells, providing a new insight on SCP‐Car‐NCs' potential for usage in the future to treat MM. [ABSTRACT FROM AUTHOR]

Phagocytic clearance of apoptotic germ cells (GCs), as well as residual bodies released from developing spermatids, is critical for Sertoli cells (SCs) to maintain inner environment homeostasis within the testis. However, the molecular mechanisms controlling the phagocytosis are ill defined. Here, we identify a new role for alpha‐enolase (ENO1), a key enzyme during glycolysis, as a molecule that facilitates testicular phagocytosis via transactivation of the engulfment and cell motility 1 (Elmo1) gene. Using immunohistochemistry and double‐labeling immunofluorescence, ENO1 was observed to be expressed exclusively in the nuclei of SCs and its expression correlated with the completion of SC differentiation. By incubating TM4 cells with different pharmacological inhibitors and establishing TM4Tnfr1−/− cells, we demonstrated that SC‐specific expression of ENO1 was under a delicate paracrine control from apoptotic GCs. In turn, persistent blockade of ENO1 expression by a validated small interfering RNA protocol resulted in the disturbance of spermatogenesis and impairment of male fertility. Furthermore, using ChIP, electrophoretic mobility shift and luciferase reporter assays, we showed that, in the presence of apoptotic GCs, ENO1 binds to the distal region of the Elmo1 promoter and facilitates transactivation of the Elmo1 gene. In agreement, overexpression of ELMO1 ameliorated ENO1 deficiency‐induced impairment of phagocytosis in TM4 cells. These data reveal a novel role for SC‐specific expression of ENO1 in regulating phagocytosis in testis, identify tumor necrosis factor‐α and ELMO1 as critical upstream and downstream factors in mediating ENO1 action, and have important implications for our understanding of paracrine control of SC function by adjacent GCs. [ABSTRACT FROM AUTHOR]

ABSTRACT Steroid-associated osteonecrosis (SAON) is one of the common complications of clinical glucocorticoid (GC) administration, with osteocyte apoptosis appearing as the primary histopathological lesion. However, the precise mechanism underlying SAON remains unknown. Epigenetic modification may be a major cause of SAON. Recently, cumulative research revealed that Ten-Eleven Translocation (TET) proteins can catalyze the conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) and then alter the epigenetic state of DNA. Here, we report that TET3-5hmC was upregulated in the femoral head tissues of SAON patients and MLO-Y4 cells with dexamethasone (Dex) treatment. Knockdown of TET3 in MLO-Y4 cells decreased 5hmC enrichment and rescued Dex-induced apoptosis. Meanwhile, the local intramedullary injection of TET3 siRNA in Sprague-Dawley rats abrogated GC-induced osteocyte apoptosis, histopathological changes, abnormal MRI signals, and bone microstructure declines in the femoral head in vivo. Moreover, a hydroxymethylated DNA immunoprecipitation (hMeDIP)-chip analysis of Dex-treated osteocytes revealed 456 different 5hmC-enriched genes. The Akt pathway was found to mediate the functional effect of Dex-induced dynamic 5hmC change; this was further verified in clinical samples. The loss of TET3 in MLO-Y4 cells abrogated Dex-induced Akt signaling pathway inhibition. Therefore, our data for the first time identify the effect of TET3-5hmC on the Akt pathway and the necessity of this signaling cascade in SAON, identifying a new potential therapeutic target. © 2016 American Society for Bone and Mineral Research. [ABSTRACT FROM AUTHOR]

Intestinal inflammation causes tight junction changes and death of epithelial cells, and plays an important role in the development of Crohn's disease (CD). CD52 monoclonal antibody (CD52 m Ab) directly targets the cell surface CD52 and is effective in depleting mature lymphocytes by cytolytic effects in vivo, leading to long-lasting changes in adaptive immunity. The aim of this study was to investigate the therapeutic effect of CD52 m Ab on epithelial barrier function in animal models of IBD. Interleukin-10 knockout mice (IL-10−/−) of 16 weeks with established colitis were treated with CD52 m Ab once a week for 2 weeks. Severity of colitis, CD4+ lymphocytes and cytokines in the lamina propria, epithelial expression of tight junction proteins, morphology of tight junctions, tumour necrosis factor- α (TNF- α)/TNF receptor 2 (TNFR2) m RNA expression, myosin light chain kinase (MLCK) expression and activity, as well as epithelial apoptosis in proximal colon were measured at the end of the experiment. CD52 m Ab treatment effectively attenuated colitis associated with decreased lamina propria CD4+ lymphocytes and interferon- γ/IL-17 responses in colonic mucosa in IL-10−/− mice. After CD52 m Ab treatment, attenuation of colonic permeability, increased epithelial expression and correct localization of tight junction proteins (occludin and zona occludens protein-1), as well as ameliorated tight junction morphology were observed in IL-10−/− mice. CD52 m Ab treatment also effectively suppressed the epithelial apoptosis, mucosa TNF- α m RNA expression, epithelial expression of long MLCK, TNFR2 and phosphorylation of MLC. Our results indicated that anti-CD52 therapy may inhibit TNF- α/TNFR2-mediated epithelial apoptosis and MLCK-dependent tight junction permeability by depleting activated T cells in the gut mucosa. [ABSTRACT FROM AUTHOR]

It has been reported by us and other groups that the expression of small GTP binding protein RhoB can be induced by genotoxic stressors and glucocorticoid (GC), a stress hormone that plays a key role in stress response. Until now stress-induced genes that confer cytoprotection under stressed conditions are largely unknown. In this study, we investigated the effects and mechanism of non-genotoxic stressors, including scalding in vivo and heat stress in vitro on the expression of RhoB. We found for the first time that both scalding, which could induce typical neuroendocrine responses of acute stress and cellular heat stress significantly increased the expression of RhoB at mRNA and protein levels. Moreover, in vitro experiments in human lung epithelial cells (A549) showed that induction of RhoB by heat stress was in a glucocorticoid receptor (GR)-independent manner and through multiple pathways including stabilization of RhoB mRNA and activation of p38 MAPK. Further experiments demonstrated that up-regulation of RhoB significantly inhibited heat stress-induced apoptosis and elevated transcriptional activity of NF-κB, but did not affect the expression of Hsp70 in A549 cells. In conclusion, we showed for the first time that RhoB was up-regulated by scalding in vivo and heat stress in vitro and played an important cytoprotective role during heat stress-induced apoptotic cell death. J. Cell. Physiol. 226: 729-738, 2011. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]