Promotion of new blood vessel formation is a new strategy for treating ischemic stroke.Non-coding miRNAs have been recently considered potential therapeutic targets for ischemic stroke.miR-181b has been shown to promo...Promotion of new blood vessel formation is a new strategy for treating ischemic stroke.Non-coding miRNAs have been recently considered potential therapeutic targets for ischemic stroke.miR-181b has been shown to promote angiogenesis in hypoxia and traumatic brain injury model,while its effect on ischemic stroke remains elusive.In this study,we found that overexpression of miR-181b in brain microvascular endothelial cells subjected to oxygen-glucose deprivation in vitro restored cell prolife ration and enhanced angiogenesis.In rat models of focal cerebral ischemia,ove rexpression of miR-181b reduced infarction volume,promoted angiogenesis in ischemic penumbra,and improved neurological function.We further investigated the molecular mechanism by which miR-181b participates in angiogenesis after ischemic stroke and found that miR-181b directly bound to the 3’-UTR of phosphatase and tensin homolog(PTEN) mRNA to induce PTEN downregulation,leading to activation of the protein kinase B(Akt) pathway,upregulated expression of vascular endothelial growth facto rs,down-regulated expression of endostatin,and promoted angiogenesis.Taken togethe r,these results indicate that exogenous miR-181b exhibits neuroprotective effects on ischemic stro ke through activating the PTEN/Akt signal pathway and promoting angiogenesis.展开更多
Lithium promotes autophagy and has a neuroprotective effect on spinal cord injury（SCI）; however, the underlying mechanisms remain unclear. Therefore, in this study, we investigated the effects of lithium and the aut...Lithium promotes autophagy and has a neuroprotective effect on spinal cord injury（SCI）; however, the underlying mechanisms remain unclear. Therefore, in this study, we investigated the effects of lithium and the autophagy inhibitor 3-methyladenine（3-MA） in a rat model of SCI. The rats were randomly assigned to the SCI, lithium, 3-MA and sham groups. In the 3-MA group, rats were intraperitoneally injected with 3-MA（3 mg/kg） 2 hours before SCI. In the lithium and 3-MA groups, rats were intraperitoneally injected with lithium（LiCl; 30 mg/kg） 6 hours after SCI and thereafter once daily until sacrifice. At 2, 3 and 4 weeks after SCI, neurological function and diffusion tensor imaging indicators were remarkably improved in the lithium group compared with the SCI and 3-MA groups. The Basso, Beattie and Bresnahan locomotor rating scale score and fractional anisotropy values were increased, and the apparent diffusion coefficient value was decreased. Immunohistochemical staining showed that immunoreactivities for Beclin-1 and light-chain 3 B peaked 1 day after SCI in the lithium and SCI groups. Immunoreactivities for Beclin-1 and light-chain 3 B were weaker in the 3-MA group than in the SCI group, indicating that 3-MA inhibits lithium-induced autophagy. Furthermore, NeuN＋ neurons were more numerous in the lithium group than in the SCI and 3-MA groups, with the fewest in the latter. Our findings show that lithium reduces neuronal damage after acute SCI and promotes neurological recovery by inducing autophagy. The neuroprotective mechanism of action may not be entirely dependent on the enhancement of autophagy, and furthermore, 3-MA might not completely inhibit all autophagy pathways.展开更多
采用单道次热压缩实验在Gleeble-1500热力模拟机上研究了不同变形速率和变形温度下Hi-B钢的软化行为。结果表明,试验钢在较低应变速率下,主要以动态回复作为软化机制,在较高应变速率下,主要以动态再结晶作为软化机制。采用回归法计算出...采用单道次热压缩实验在Gleeble-1500热力模拟机上研究了不同变形速率和变形温度下Hi-B钢的软化行为。结果表明,试验钢在较低应变速率下,主要以动态回复作为软化机制,在较高应变速率下,主要以动态再结晶作为软化机制。采用回归法计算出动态回复的变形激活能和应变指数分别为287.12 k J/mol和4.88,由此建立了试验钢在低应变速率下的动态回复模型。展开更多
基金supported by the National Natural Science Foundation of China,Nos.81801169 (to LXX),82071404 (to HC),81870952 (to HMW)。
文摘Promotion of new blood vessel formation is a new strategy for treating ischemic stroke.Non-coding miRNAs have been recently considered potential therapeutic targets for ischemic stroke.miR-181b has been shown to promote angiogenesis in hypoxia and traumatic brain injury model,while its effect on ischemic stroke remains elusive.In this study,we found that overexpression of miR-181b in brain microvascular endothelial cells subjected to oxygen-glucose deprivation in vitro restored cell prolife ration and enhanced angiogenesis.In rat models of focal cerebral ischemia,ove rexpression of miR-181b reduced infarction volume,promoted angiogenesis in ischemic penumbra,and improved neurological function.We further investigated the molecular mechanism by which miR-181b participates in angiogenesis after ischemic stroke and found that miR-181b directly bound to the 3’-UTR of phosphatase and tensin homolog(PTEN) mRNA to induce PTEN downregulation,leading to activation of the protein kinase B(Akt) pathway,upregulated expression of vascular endothelial growth facto rs,down-regulated expression of endostatin,and promoted angiogenesis.Taken togethe r,these results indicate that exogenous miR-181b exhibits neuroprotective effects on ischemic stro ke through activating the PTEN/Akt signal pathway and promoting angiogenesis.
基金supported by the Beijing Excellent Talent Training Funding in China,No.2017000021469G215(to DZ)the Youth Science Foundation of Beijing Tiantan Hospital of China,No.2016-YQN-14(to DZ)+1 种基金the Natural Science Foundation of Capital Medical University of China,No.PYZ2017082(to DZ)the Xi’an Science and Technology Project in China,No.2016048SF/YX04(3)(to XHL)
文摘Lithium promotes autophagy and has a neuroprotective effect on spinal cord injury（SCI）; however, the underlying mechanisms remain unclear. Therefore, in this study, we investigated the effects of lithium and the autophagy inhibitor 3-methyladenine（3-MA） in a rat model of SCI. The rats were randomly assigned to the SCI, lithium, 3-MA and sham groups. In the 3-MA group, rats were intraperitoneally injected with 3-MA（3 mg/kg） 2 hours before SCI. In the lithium and 3-MA groups, rats were intraperitoneally injected with lithium（LiCl; 30 mg/kg） 6 hours after SCI and thereafter once daily until sacrifice. At 2, 3 and 4 weeks after SCI, neurological function and diffusion tensor imaging indicators were remarkably improved in the lithium group compared with the SCI and 3-MA groups. The Basso, Beattie and Bresnahan locomotor rating scale score and fractional anisotropy values were increased, and the apparent diffusion coefficient value was decreased. Immunohistochemical staining showed that immunoreactivities for Beclin-1 and light-chain 3 B peaked 1 day after SCI in the lithium and SCI groups. Immunoreactivities for Beclin-1 and light-chain 3 B were weaker in the 3-MA group than in the SCI group, indicating that 3-MA inhibits lithium-induced autophagy. Furthermore, NeuN＋ neurons were more numerous in the lithium group than in the SCI and 3-MA groups, with the fewest in the latter. Our findings show that lithium reduces neuronal damage after acute SCI and promotes neurological recovery by inducing autophagy. The neuroprotective mechanism of action may not be entirely dependent on the enhancement of autophagy, and furthermore, 3-MA might not completely inhibit all autophagy pathways.
文摘采用单道次热压缩实验在Gleeble-1500热力模拟机上研究了不同变形速率和变形温度下Hi-B钢的软化行为。结果表明,试验钢在较低应变速率下,主要以动态回复作为软化机制,在较高应变速率下,主要以动态再结晶作为软化机制。采用回归法计算出动态回复的变形激活能和应变指数分别为287.12 k J/mol和4.88,由此建立了试验钢在低应变速率下的动态回复模型。
