N-乙酰半胱氨酸通过AMPK/SIRT1途径抑制缺氧诱导的大鼠脑血管内皮细胞损伤

目的研究N-乙酰半胱氨酸(NAC)对缺氧诱导脑血管内皮细胞损伤的调节作用及分子机制。方法选择SD大鼠分离培养脑血管内皮细胞,分为常氧组、缺氧组、0. 5 NAC组(缺氧+0. 5 mol/L NAC)、1. 0 NAC组(缺氧+1. 0 mol/L NAC)、NAC+8-bAMP组(缺氧+1. 0 mol/L NAC+1. 0 mol/L 8-bAMP)。采用MTS法检测细胞增殖活力,采用TUNEL染色检测凋亡率,采用试剂盒检测氧化应激指标,采用Western blot检测凋亡基因、AMPK/SIRT1通路分子的表达量。结果缺氧组细胞OD490值、T-AOC含量及B淋巴细胞瘤2(Bcl-2)、p-AMP活化蛋白激酶(pAMPK)、去乙酰化酶Sirtuin1(SIRT1)表达量均明显低于常氧组;缺氧组细胞凋亡率、细胞中活性氧(ROS)、丙二醛(MDA)、8-羟基脱氧鸟苷(8-OHDG)含量及bcl-2相关X蛋白(bax)、细胞色素C(Cyt-C)、含半胱氨酸的天冬氨酸蛋白水解酶3(Caspase-3)的表达量均明显高于常氧组。0. 5 NAC组、1. 0 NAC组细胞OD490值、T-AOC量及Bcl-2、pAMPK、SIRT1表达量均明显高于缺氧组; 0. 5 NAC组、1. 0 NAC组细胞凋亡率、ROS、MDA、8-OHDG含量及Caspase-3、Cyt-C、Bax的表达量均明显低于缺氧组。NAC+8-bAMP组细胞OD490值、T-AOC及Bcl-2、p-AMPK、SIRT1表达量均明显低于1. 0 NAC组; NAC+8-bAMP组凋亡率、ROS、MDA、8-OHDG含量及Caspase-3、Cyt-C、Bax的表达量均明显高于1. 0 NAC组。结论 NAC能够通过激活AMPK/SIRT1通路来减轻氧化应激及线粒体凋亡介导的脑血管内皮细胞损伤。     

MicroRNA-181c provides neuroprotection in an intracerebral hemorrhage model

Apoptosis is an important factor during the early stage of intracerebral hemorrhage.MiR-181 c plays a key regulatory role in apoptosis.However,whether miR-181 c is involved in apoptosis of prophase cells after intracerebral hemorrhage remains unclear.Therefore,in vitro and in vivo experiments were conducted to test this hypothesis.In vivo experiments:collagenase type VII was injected into the basal ganglia of adult Sprague-Dawley rats to establish an intracerebral hemorrhage model.MiR-181 c mimic or inhibitor was injected in situ 4 hours after intracerebral hemorrhage.Neurological functional defects(neurological severity scores)were assessed 1,7,and 14 days after model establishment.Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and western blot assay were conducted 14 days after model establishment.In vitro experiments:PC12 cells were cultured under oxygen-glucose deprivation,and hemins were added to simulate intracerebral hemorrhage in vitro.MiR-181 c mimic or inhibitor was added to regulate miR-181 c expression.3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay,luciferase reporter system,and western blot assay were performed.Experimental results revealed differences in miR-181 c expression in brain tissues of both patients and rats with cerebral hemorrhage.In addition,in vitro experiments found that miR-181 c overexpression could upregulate the Bcl-2/Bax ratio to inhibit apoptosis,while inhibition of miR-181 c expression could reduce the Bcl-2/Bax ratio and aggravate apoptosis of cells.Regulation of apoptosis occurred through the phosphoinositide 3 kinase(PI3 K)/Akt pathway by targeting of phosphatase and tensin homolog deleted on chromosome ten(PTEN).Higher miR-181 c overexpression correlated with lower neurological severity scores,indicating better recovery of neurological function.In conclusion,miR-181 c affects the prognosis of intracerebral hemorrhage by regulating apoptosis,and these effects might be directly mediated and regulated by targeting of the PTEN\PI3 K/Akt pathway and Bcl-2/Bax ratio.Furthermore,these results indicated that miR-181 c played a neuroprotective role in intracerebral hemorrhage by regulating apoptosis of nerve cells,thus providing a potential target for the prevention and treatment of intracerebral hemorrhage.Testing of human serum was authorized by the Ethics Committee of China Medical University(No.2012-38-1)on February 20,2012.The protocol was registered with the Chinese Clinical Trial Registry(Registration No.ChiCTR-COC-17013559).The animal study was approved by the Institutional Animal Care and Use Committee of China Medical University(approval No.2017008)on March 8,2017.     

The voltage-gated calcium channel CaV1.2 promotes adult oligodendrocyte progenitor cell survival in the mouse corpus callosum but not motor cortex

Throughout life, oligodendrocyte progenitor cells (OPCs) proliferate and differentiate into myelinating oligodendrocytes. OPCs express cell surface receptors and channels that allow them to detect and respond to neuronal activity, including voltage-gated calcium channel (VGCC)s. The major L-type VGCC expressed by developmental OPCs, CaV1.2, regulates their differentiation. However, it is unclear whether CaV1.2 similarly influences OPC behavior in the healthy adult central nervous system (CNS). To examine the role of CaV1.2 in adulthood, we conditionally deleted this channel from OPCs by administering tamoxifen to P60 Cacna1c ^fl/fl (control) and Pdgfrα-CreER:: Cacna1c ^fl/fl (CaV1.2-deleted) mice. Whole cell patch clamp analysis revealed that CaV1.2 deletion reduced L-type voltage-gated calcium entry into adult OPCs by ~60%, confirming that it remains the major L-type VGCC expressed by OPCs in adulthood. The conditional deletion of CaV1.2 from adult OPCs significantly increased their proliferation but did not affect the number of new oligodendrocytes produced or influence the length or number of internodes they elaborated. Unexpectedly, CaV1.2 deletion resulted in the dramatic loss of OPCs from the corpus callosum, such that 7 days after tamoxifen administration CaV1.2-deleted mice had an OPC density ~42% that of control mice. OPC density recovered within 2 weeks of CaV1.2 deletion, as the lost OPCs were replaced by surviving CaV1.2-deleted OPCs. As OPC density was not affected in the motor cortex or spinal cord, we conclude that calcium entry through CaV1.2 is a critical survival signal for a subpopulation of callosal OPCs but not for all OPCs in the mature CNS.     

Growth‐promoting effects of low‐level butyl benzyl phthalate exposure on human neuroblastoma SH‐SY5Y cells

The purpose of present study was to investigate the impact of butyl benzyl phthalate (BBP) on SH‐SY5Y neuroblastoma cells in vitro. The cell counting kit‐8 was used to measure cell proliferation and flow cytometry was utilized to study cell cycle phases and apoptosis. Western blotting and quantitative real‐time polymerase chain reaction were used to detect levels of aromatase, estrogen receptors (ERs) and some apoptosis and cell cycle‐related genes. Results showed BBP‐stimulated SH‐SY5Y cells in a dose‐dependent manner and produced a reverted U‐shaped dose‐response curve. BBP at lower concentrations (0.01 and 0.1 μm ) significantly induced cell proliferation while inhibited cell growth at 300 μm . The promoting effect of estradiol could be entirely blocked by administration of ICI182 780, a pure antagonist of ERs, while the effect of BBP could be partly blocked. Additionally, we confirmed 0.1 μm BBP‐induced cell proliferation caused the arrest of cells in S phase and inhibited apoptosis, which might be partially explained by the decreased expression of p53, the increased expression of proliferating cell nuclear antigen, Bcl‐2 and cell cycle regulator cyclin‐D1, and the activation of aromatase. The addition of ICI182 780 had no effect on BBP‐induced ERβ mRNA expression, whereas ICI182 780 could effectively counteract the effect of estradiol. Moreover, pretreatment with ICI182 780 could block the induction of aromatase protein expression and activity by BBP, showing an involvement of ERs. Except for the ER pathway, these results showed there might be other pathways involved in promoting the effects of low‐level BBP on SH‐SY5Y cells, which require further investigation.     

Ginsenoside Rg1 prevents acetaminophen-induced oxidative stress and apoptosis via Nrf2/ARE signaling pathway

Inappropriate use of acetaminophen (APAP) can lead to morbidity and mortality secondary to hepatic necrosis. Ginsenoside Rg1 is a major active ingredient in processed Panax ginseng, which is proved to elicit biological effects. We hypothesized the beneficial effect of Rg1 on APAP-mediated hepatotoxicity was through Nrf2/ARE pathway. The study was conducted in cells and mice, comparing the actions of Rg1. Rg1 significantly improved cell survival rates and promoted the expression of antioxidant proteins. Meanwhile, Rg1 reduced the excessive ROS and the occurrence of cell apoptosis, which were related to Nrf2/ARE pathway. Expression of Nrf2 has a certain cell specificity.

     

Perilipin2 inhibits diabetic nephropathy-induced podocyte apoptosis by activating the PPARγ signaling pathway

Podocyte apoptosis plays a pivotal role in the pathogenesis of diabetic nephropathy (DN). The main purpose of this study was to investigate the effects of perilipin2 on high glucose (HG)-induced podocyte apoptosis and associated mechanisms. Differentially expressed genes (DEGs) in BTBR ob/ob mice vs. nondiabetic mice kidneys were obtained from GSE106841 dataset and picked out using the ‘limma’ package. The protein-protein interaction (PPI) network was constructed using the Search Tool for the Retrieval of Interacting Genes (STRING) and was visualized by Cytoscape. Perilipin2 was a hub gene using the cytoHubba plug-in from Cytoscape. Gene ontology (GO) analysis revealed that the 126 overlapping DEGs were mainly enriched in ‘oxidation reduction’ [biological process, (BP)], metal ion binding’ [molecular function, (MF)] and ‘extracellular region’ [cellular component, (CC)]. KEGG pathway analysis revealed that perilipin2 was mainly involved in ‘PPAR signaling pathway’. DN inhibited perilipin2 expression and PPARγ expression, as by both in vitro and in vivo studies. In vitro experiments demonstrated that perilipin2 inhibition could not only reduced PPARγ expression in podocytes, it could also promote the apoptosis, and inhibit the viability in HG treated podocytes using western blot, CCK8 and flow cytometry assays. Perilipin2 overexpression reversed the effects of HG on inhibiting podocalyxin, nephrin, precursor (pro)-caspase-3/-9 and PPARγ protein expression and increasing cleaved caspase-3/-9 protein expression. Furthermore, the functions of perilipin2 overexpression reversing HG-induced podocyte apoptosis were inhibited by PPARγ inhibitor. In conclusion, the functions of DN-induced podocyte apoptosis were inhibited by activation of the PPARγ signaling pathway caused by perilipin2 overexpression.     

葡萄膜炎并发白内障患者晶状体前囊膜中NLRP3炎症小体相关蛋白的表达和前囊膜超微结构改变

目的　探究葡萄膜炎并发白内障患者晶状体前囊膜中NLRP3炎症小体相关蛋白的表达和前囊膜超微结构改变。方法　随机选取2018年8月至2019年6月在我院诊治的葡萄膜炎并发白内障患者17例(22眼)作为试验组；老年性白内障患者10例(18眼)作为对照组。均于白内障超声乳化手术中环形撕囊获取前囊膜。采用免疫组织化学法检测两组患者晶状体前囊膜NLRP3炎症小体的三个组成结构NLRP3、Caspase-1和接头蛋白ASC的蛋白表达，并对前囊膜进行电镜观察。结果　两组患者晶状体前囊膜中均有NLRP3炎症小体相关蛋白的表达；试验组晶状体前囊膜中NLRP3、Caspase-1及接头蛋白ASC（光密度值分别为0.383±0.067、0.313±0.058、0.335±0.035）表达水平均明显高于对照组（光密度值分别为0.330±0.085、0.271±0.039、0.268±0.036）（均为P<0.05）。试验组患者前囊膜的晶状体上皮细胞可见明显的细胞核固缩，染色质浓缩边集，细胞核膜皱褶、轻度增宽，线粒体形态基本正常、部分线粒体嵴突消失，细胞质中可见典型的凋亡小体。对照组有轻度凋亡改变。结论　NLRP3炎症小体可能参与了葡萄膜炎并发白内障的发病过程，细胞凋亡是葡萄膜炎并发白内障的重要病理改变。     

Claudin-15 overexpression inhibits proliferation and promotes apoptosis of Schwann cells in vitro

Our previous experiments have discovered that Claudin-15 was up-regulated in Schwann cells of the distal nerve stumps of rat models of sciatic nerve injury.However,how Claudin-15 affects Schwann cell function is still unknown.This study aimed to identify the effects of Claudin-15 on proliferation and apoptosis of Schwann cells cultured in vitro and explore the underlying mechanisms.Primary Schwann cells were obtained from rats.Claudin-15 in Schwann cells was knocked down using siRNA(siRNA-1 group)compared with the negative control siRNA transfection group(negative control group).Claudin-15 in Schwann cells was overexpressed using pGV230-Claudin-15 plasmid(pGV230-Claudin-15 group).The pGV230 transfection group(pGV230 group)acted as the control of the pGV230-Claudin-15 group.Cell proliferation was analyzed with EdU assay.Cell apoptosis was analyzed with flow cytometric analysis.Cell migration was analyzed with Transwell inserts.The mRNA and protein expressions were analyzed with quantitative polymerase chain reaction assay and western blot assay.The results showed that compared with the negative control group,cell proliferation rate was up-regulated;p-AKT/AKT ratio,apoptotic rate,p-c-Jun/c-Jun ratio,mRNA expression of protein kinase C alpha,Bcl-2 and Bax were down-regulated;and mRNA expression of neurotrophins basic fibroblast growth factor and neurotrophin-3 were increased in the siRNA-1 group.No significant difference was found in cell migration between the negative control and siRNA-1 groups.Compared with the pGV230 group,the cell proliferation rate was down-regulated;apoptotic rate,p-c-Jun/c-Jun ratio and c-Fos protein expression increased;mRNA expression of protein kinase C alpha and Bax decreased;and mRNA expressions of neurotrophins basic fibroblast growth factor and neurotrophin-3 were up-regulated in the pGV230-Claudin-15 group.The above results demonstrated that overexpression of Claudin-15 inhibited Schwann cell proliferation and promoted Schwann cell apoptosis in vitro.Silencing of Claudin-15 had the reverse effect and provided neuroprotective effect.This study was approved by the Experimental Animal Ethics Committee of Jilin University of China(approval No.2016-nsfc001)on March 5,2016.