Autophagy inhibits the mesenchymal stem cell aging induced by D-galactose through ROS/JNK/p38 signalling

Autophagy and cellular senescence are two critical responses of mammalian cells to stress and may have a direct relationship given that they respond to the same set of stimuli, including oxidative stress, DNA damage, and telomere shortening. Mesenchymal stem cells (MSCs) have emerged as reliable cell sources for stem cell transplantation and are currently being tested in numerous clinical trials. However, the effects of autophagy on MSC senescence and corresponding mechanisms have not been fully evaluated. Several studies demonstrated that autophagy level increases in aging MSCs and the downregulation of autophagy can delay MSC senescence, which is inconsistent with most studies that showed autophagy could play a protective role in stem cell senescence. To further study the relationship between autophagy and MSC senescence and explore the effects and mechanisms of premodulated autophagy on MSC senescence, we induced the up- or down-regulation of autophagy by using rapamycin (Rapa) or 3-methyladenine, respectively, before MSC senescence induced by D-galactose (D-gal). Results showed that pretreatment with Rapa for 24 hours remarkably alleviated MSC aging induced by D-gal and inhibited ROS generation. p-Jun N-terminal kinases (JNK) and p-38 expression were also clearly decreased in the Rapa group. Moreover, the protective effect of Rapa on MSC senescence can be abolished by enhancing the level of ROS, and p38 inhibitor can reverse the promoting effect of H₂O₂ on MSC senescence. In summary, the present study indicates that autophagy plays a protective role in MSC senescence induced by D-gal, and ROS/JNK/p38 signalling plays an important mediating role in autophagy-delaying MSC senescence.     

甲烷生理盐水对肝缺血再灌注小鼠肝线粒体的影响

 目的 在肝缺血再灌注小鼠模型中研究甲烷对肝线粒体的影响。方法 将C57小鼠18只随机分为空白对照组(SHAM组)、缺血再灌注组(IR组)和甲烷盐水治疗组(IR+CH4组),每组6只,采用70%肝缺血再灌注模型,IR+CH4组再灌注开始前予甲烷生理盐水10 ml/kg腹腔内注射,留取标本检测氧化、抗氧化、线粒体相关指标。结果 与IR组相比,IR+CH4降低了ROS水平(t=3.154,P=0.0083)及MDA(t=3.738, P=0.028)水平,提高了GSH(t=2.687, P=0.0177)及SOD(t=3.480, P=0.0037)水平;采用Westen blot 检测蛋白的表达,与对照组相比,IR组线粒体融合蛋白Mfn1(q=7.57,P＜0.05)和OPA1(q=6.41,P＜0.05)表达减少,分裂蛋白DLP1(q=3.718,P＜0.05)表达增加;与IR组相比,IR+CH4组融合蛋白Mfn1(q=5.277, P＜0.05)增加,分裂蛋白DLP1(q=6.700,P＜0.05)表达下降;IR组PINK1(q=4.606, P＜0.05)表达上调,IR+CH4组PINK1(q=3.922, P＜0.05)表达下降。结论 甲烷生理盐水可降低氧化应激,提高机体抗氧化能力,促进线粒体融合,减少分裂,促进线粒体功能的恢复。     

Targeting intrinsic apoptosis and other forms of cell death by BH3-mimetics in glioblastoma

Introduction: Novel approaches to treat malignant brain tumors are necessary since these neoplasms still display an unfavorable prognosis.

Areas covered: In this review, the authors summarize and analyze recent preclinical data that suggest that targeting intrinsic apoptosis may be a suitable strategy for the treatment of malignant gliomas. They focus on the anti-apoptotic Bcl-2 family members of proteins and the recent drug developments in that field with a special focus on BH3-mimetics. With the discovery of BH3-mimetics that interfere with anti-apoptotic Bcl-2 family members in the low nanomolar range significant excitement has been generated towards these class of inhibitors, such as ABT-737, ABT-263 and the most recent successor, ABT-199 which is most advanced with respect to clinical application. The authors discuss the more recent selective inhibitors of Bcl-xL and Mcl-1. Concerning Mcl-1, these novel classes of inhibitors have the potential to impact malignant gliomas since these tumors reveal increased levels of Mcl-1.

Expert opinion: The recent development of certain small molecules raises significant hope that intrinsic apoptosis might soon be efficiently targetable for malignancies of the central nervous system. That being said, additional studies are necessary to determine which of the BH3-mimetics might be most suitable.     

葛根素调节AMPK-mTOR信号通路抑制自噬改善大鼠脑缺血再灌注损伤研究

目的探讨葛根素通过腺苷一磷酸活化蛋白激酶(AMPK)-哺乳动物雷帕霉素靶蛋白(m TOR)-Unc-51样激酶1(Ulk1)通路抑制自噬改善大鼠脑缺血再灌注损伤的作用。方法 40只雄性SD大鼠随机分为4组,即假手术组、模型组及葛根素低、高剂量(50、100 mg/kg)组。各组大鼠连续给药7 d,末次给药30min后,采用线栓法制备大鼠大脑中动脉栓塞(middle cerebral artery occlusion,MCAO)模型,缺血1.5 h再灌注24 h后,进行神经功能评分,TTC染色观察脑梗死体积,电镜观察自噬小体的形成,Western blotting法检测海马组织中微管相关蛋白1轻链3(LC3)、p62、AMPK、p-AMPK、m TOR、p-mTOR、Ulk1、p S757-Ulk1蛋白表达水平。结果与假手术组比较,模型组大鼠神经功能评分显著增加,脑梗死体积明显增大,自噬小体增多,LC3-II/LC3-I显著增加,p62蛋白表达水平显著降低,p-AMPK表达水平显著升高,p-m TOR和p S757-Ulk1蛋白表达水平显著降低。与模型组比较,葛根素各组大鼠的神经功能损伤明显改善,脑梗死体积减小,自噬小体减少,LC3-II/LC3-I显著降低,p62蛋白表达水平显著升高,p-AMPK蛋白表达水平显著降低,p-m TOR和p S757-Ulk1蛋白表达水平显著升高。结论葛根素可能通过调控AMPK-m TOR-Ulk1信号通路抑制自噬的过度发生,从而减轻脑缺血再灌注损伤的发生。     

自噬相关基因在类风湿关节炎滑膜组织的表达及调控机制

目的 研究自噬相关基因(ATG)在类风湿关节炎(RA)中的表达调控和自噬机制。方法 从GSE55235和GSE55457中鉴定出RA的差异表达基因(DEG),结合人类自噬数据库,筛选出差异表达自噬相关基因(DE-ATG)。利用STRING 11.0和GeneMANIA数据库建立蛋白互作网络。此外,NetworkAnalyst和Cytoscape建立转录因子-基因-miRNA共表达网络。最后,受试者工作特征曲线分析和DrugBank鉴定预测生物标志物的效能和靶向药物的性能。GraphPad prism 8.2.1和R 4.0.3用于统计分析和图形制作。结果 485个DEG在T细胞激活、激素调节、破骨细胞分化、RA和趋化因子等信号通路富集。11个DE-ATG通过hsa-mir-155-5p、RUNX1、TP53和SOX2等调控RA滑膜组织的表达,与四氯二苯二氧芑、二氧化硅有较强的环境因子调控关系。受试者工作特征曲线分析确定了具有良好敏感性和特异性的基因,如MYC、MAPK8、CDKN1A和TNFSF10,可用于区分某些表型,这可能是RA的新型生物标志物。结论 DE-ATG在RA中表达下调可能会促进软骨细胞凋亡和分解,新型生物标志物的确立为诊断和治疗RA提供了新思路和方法,转录因子-基因-miRNA网络的建立为解析滑膜炎症和关节软骨破坏提供直接证据。     

PCGEM1 stimulates proliferation of osteoarthritic synoviocytes by acting as a sponge for miR‐770

Long non‐coding RNAs (lncRNAs) have been reported to play important roles in cellular metabolism and development. Various diseases have been associated with aberrant expression of lncRNAs and the related dysregulation of mRNAs. An lncRNA profiling assay was carried out to identify the key lncRNA in osteoarthritic human synoviocytes; the results revealed that prostate cancer gene expression marker 1 (PCGEM1) was significantly overexpressed in osteoarthritic synoviocytes. Exogenous overexpression of PCGEM1 inhibited apoptosis, induced autophagy, and stimulated the proliferation of human synoviocytes. The increased expression of PCGEM1 in human synoviocytes also suppressed the expression of miR‐770. Transfection of the miR‐770 precursor resulted in reduced proliferation, and induced apoptosis of human synoviocytes. This effect of miR‐770 expression was reversed by co‐introduction of PCGEM1. Target validation showed a direct binding between PCGEM1 and miR‐770. We demonstrate that PCGEM1 act as sponge lncRNA for miR‐770 that regulates proliferation/apoptosis and autophagy, and suggest PCGEM1 as possible target for OA therapy. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:412–418, 2016.     

The possible role of interleukin-33 as a new player in the pathogenesis of contrast-induced nephropathy in diabetic rats

Introduction: Patients with diabetic kidney disease (DKD) are more prone to contrast-induced nephropathy (CN). Apoptosis and autophagy were found to be essential in the pathogenesis of DKD. Interleukin-33 (IL-33) is a cytokine, but its role in DKD and CN is unknown. As IL-33 is modulated by apoptosis, we aimed to determine the relationship between IL-33 apoptosis and autophagy in DKD with CN. Materials and methods: Thirty male Sprague–Dawley rats were enrolled and randomly allocated into three groups. The first group was comprised of healthy rats (HRs), whereas the other two groups were made up of diabetic rats (DRs) and diabetic rats with CN (DRs?+?CN). All groups except the HRs received 50?mg/kg/day of streptozotocin (STZ). The DRs?+?CN group was induced by administering 1.5?mg/kg of intravenous radiocontrast dye on the 35th day. Results: We observed increased IL-33 in the kidney tissue following induction of CN in the DRs. The DRs showed moderate immunopositivity, and the DRs?+?CN showed severe immunopositivity for caspase-3, cleaved caspase-3, caspase-8, caspase-9, LC3B, and Beclin-1 in tubular cells and glomeruli. The DRs also showed moderate immunopositivity in tubular cells, and the DRs?+?CN group showed severe immunopositivity for IL-33 in tubular cells. Increased caspase-3 was found in both glomeruli and tubuli; however, we could not demonstrate IL-33 in glomeruli. This could be secondary to inactivation of IL-33 via increased caspase-3 activity. Conclusion: The release of IL-33 from necrotic cells might induce autophagy, which can further balance the effects of increased apoptosis secondary to CN in DKD.     

以Survivin为靶标的肿瘤治疗策略

Survivin是凋亡抑制蛋白(inhibitor of apoptosis protein,IAP)家族的新成员,参与调控细胞重要的生理病理过程,具有抑制细胞凋亡、促进细胞增殖和肿瘤间质血管形成等作用.Survivin在正常终末分化组织中几乎检测不到,而在大多数肿瘤组织中高表达,其异常高表达与肿瘤的化疗耐药、肿瘤复发以及患者生存率密切相关.由于在肿瘤发生和发展中起重要作用,Survivin成为肿瘤基因诊治的理想靶点.本文将就Survivin分子功能、Survivin与肿瘤的关系以及与Survivin相关的肿瘤治疗策略作一综述.