Brain functional impairment after stroke is common;however,the molecular mechanisms of post-stroke recovery remain unclear.It is well-recognized that age is the most important independent predictor of poor outcomes af...Brain functional impairment after stroke is common;however,the molecular mechanisms of post-stroke recovery remain unclear.It is well-recognized that age is the most important independent predictor of poor outcomes after stroke as older patients show poorer functional outcomes following stroke.Mounting evidence suggests that axonal regeneration and angiogenesis,the major forms of brain plasticity responsible for post-stroke recovery,diminished with advanced age.Previous studies suggest that Ras-related C3 botulinum toxin substrate(Rac)1 enhances stroke recovery as activation of Rac1 improved behavior recovery in a young mice stroke model.Here,we investigated the role of Rac1 signaling in long-term functional recovery and brain plasticity in an aged(male,18 to 22 months old C57BL/6J)brain after ischemic stroke.We found that as mice aged,Rac1 expression declined in the brain.Delayed overexpression of Rac1,using lentivirus encoding Rac1 injected day 1 after ischemic stroke,promoted cognitive(assessed using novel object recognition test)and sensorimotor(assessed using adhesive removal tests)recovery on days 14–28.This was accompanied by the increase of neurite and proliferative endothelial cells in the periinfarct zone assessed by immunostaining.In a reverse approach,pharmacological inhibition of Rac1 by intraperitoneal injection of Rac1 inhibitor NSC23766 for 14 successive days after ischemic stroke worsened the outcome with the reduction of neurite and proliferative endothelial cells.Furthermore,Rac1 inhibition reduced the activation of p21-activated kinase 1,the protein level of brain-derived neurotrophic factor,and increased the protein level of glial fibrillary acidic protein in the ischemic brain on day 28 after stroke.Our work provided insight into the mechanisms behind the diminished plasticity after cerebral ischemia in aged brains and identified Rac1 as a potential therapeutic target for improving functional recovery in the older adults after stroke.展开更多
Background Vitamin A(VA)and its metabolite,retinoic acid(RA),are of great interest for their wide range of physiological functions.However,the regulatory contribution of VA to mitochondrial and muscle fiber compositio...Background Vitamin A(VA)and its metabolite,retinoic acid(RA),are of great interest for their wide range of physiological functions.However,the regulatory contribution of VA to mitochondrial and muscle fiber composition in sheep has not been reported.Method Lambs were injected with 0(control)or 7,500 IU VA palmitate into the biceps femoris muscle on d 2 after birth.At the age of 3 and 32 weeks,longissimus dorsi(LD)muscle samples were obtained to explore the effect of VA on myofiber type composition.In vitro,we investigated the effects of RA on myofiber type composition and intrinsic mechanisms.Results The proportion of type I myofiber was greatly increased in VA-treated sheep in LD muscle at harvest.VA greatly promoted mitochondrial biogenesis and function in LD muscle of sheep.Further exploration revealed that VA elevated PGC-1αmRNA and protein contents,and enhanced the level of p38 MAPK phosphorylation in LD muscle of sheep.In addition,the number of type I myofibers with RA treatment was significantly increased,and type IIx myofibers was significantly decreased in primary myoblasts.Consistent with in vivo experiment,RA significantly improved mitochondrial biogenesis and function in primary myoblasts of sheep.We then used si-PGC-1αto inhibit PGC-1αexpression and found that si-PGC-1αsignificantly abrogated RA-induced the formation of type I myofibers,mitochondrial biogenesis,MitoTracker staining intensity,UQCRC1 and ATP5A1 expression,SDH activity,and enhanced the level of type IIx muscle fibers.These data suggested that RA improved mitochondrial biogenesis and function by promoting PGC-1αexpression,and increased type I myofibers.In order to prove that the effect of RA on the level of PGC-1αis caused by p38 MAPK signaling,we inhibited the p38 MAPK signaling using a p38 MAPK inhibitor,which significantly reduced RA-induced PGC-1αand MyHC I levels.Conclusion VA promoted PGC-1αexpression through the p38 MAPK signaling pathway,improved mitochondrial biogenesis,and altered the composition of muscle fiber type.展开更多
目的研究麻杏解毒合剂对冠状病毒肺炎模型小鼠炎性因子表达的影响,基于p38MAPK/AP-1通路研究其疗效机制。方法60只昆明种(KM)小鼠随机分成空白对照组、模型组、p38MAPK抑制剂组及麻杏解毒合剂高、中、低剂量组,每组10只。采用模拟寒湿...目的研究麻杏解毒合剂对冠状病毒肺炎模型小鼠炎性因子表达的影响,基于p38MAPK/AP-1通路研究其疗效机制。方法60只昆明种(KM)小鼠随机分成空白对照组、模型组、p38MAPK抑制剂组及麻杏解毒合剂高、中、低剂量组,每组10只。采用模拟寒湿环境、表达h ACE2的重组腺相关病毒转导、SARS-CoV-2spike假病毒气管内给药建立小鼠冠状病毒肺炎模型。检测各组小鼠血清炎性因子、肺组织病理改变、肺组织p38MAPK、c-jun、c-fos的mRNA水平和蛋白表达情况。结果与空白对照组比较,模型组小鼠血清炎性因子白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)、白细胞介素-8(IL-8)、肿瘤坏死因子-α(TNF-α)的表达均显著升高(P<0.01),肺组织炎性改变明显,c-fos m RNA水平和p-p38、c-fos、c-jun蛋白表达均显著增加(P<0.05)。与模型组比较,麻杏解毒合剂高、中剂量组小鼠血清炎性因子显著降低(P<0.01或P<0.05),小鼠肺组织炎性损伤明显减轻,同时肺组织中c-fos的mRNA水平和p-p38、c-fos的蛋白表达均显著下调(P<0.05)。结论麻杏解毒合剂能降低病毒性肺炎模型小鼠血清炎性因子水平,减轻肺组织炎性损伤,其疗效机制与抑制p38MAPK蛋白的磷酸化,下调AP-1通路mRNA及蛋白表达有关。展开更多
基金supported by NIH grants RF1 AG069466(to JL and LDM),R01 NS099628(to JL),and AG069466(to JL and LDM)the American Heart Association award 20POST35180172(to FB)。
文摘Brain functional impairment after stroke is common;however,the molecular mechanisms of post-stroke recovery remain unclear.It is well-recognized that age is the most important independent predictor of poor outcomes after stroke as older patients show poorer functional outcomes following stroke.Mounting evidence suggests that axonal regeneration and angiogenesis,the major forms of brain plasticity responsible for post-stroke recovery,diminished with advanced age.Previous studies suggest that Ras-related C3 botulinum toxin substrate(Rac)1 enhances stroke recovery as activation of Rac1 improved behavior recovery in a young mice stroke model.Here,we investigated the role of Rac1 signaling in long-term functional recovery and brain plasticity in an aged(male,18 to 22 months old C57BL/6J)brain after ischemic stroke.We found that as mice aged,Rac1 expression declined in the brain.Delayed overexpression of Rac1,using lentivirus encoding Rac1 injected day 1 after ischemic stroke,promoted cognitive(assessed using novel object recognition test)and sensorimotor(assessed using adhesive removal tests)recovery on days 14–28.This was accompanied by the increase of neurite and proliferative endothelial cells in the periinfarct zone assessed by immunostaining.In a reverse approach,pharmacological inhibition of Rac1 by intraperitoneal injection of Rac1 inhibitor NSC23766 for 14 successive days after ischemic stroke worsened the outcome with the reduction of neurite and proliferative endothelial cells.Furthermore,Rac1 inhibition reduced the activation of p21-activated kinase 1,the protein level of brain-derived neurotrophic factor,and increased the protein level of glial fibrillary acidic protein in the ischemic brain on day 28 after stroke.Our work provided insight into the mechanisms behind the diminished plasticity after cerebral ischemia in aged brains and identified Rac1 as a potential therapeutic target for improving functional recovery in the older adults after stroke.
基金funded by the National Natural Science Foundation of China(31972559)the Distinguished and Excellent Young Scholar Cultivation Project of Shanxi Agricultural University(2022JQPYGC01).
文摘Background Vitamin A(VA)and its metabolite,retinoic acid(RA),are of great interest for their wide range of physiological functions.However,the regulatory contribution of VA to mitochondrial and muscle fiber composition in sheep has not been reported.Method Lambs were injected with 0(control)or 7,500 IU VA palmitate into the biceps femoris muscle on d 2 after birth.At the age of 3 and 32 weeks,longissimus dorsi(LD)muscle samples were obtained to explore the effect of VA on myofiber type composition.In vitro,we investigated the effects of RA on myofiber type composition and intrinsic mechanisms.Results The proportion of type I myofiber was greatly increased in VA-treated sheep in LD muscle at harvest.VA greatly promoted mitochondrial biogenesis and function in LD muscle of sheep.Further exploration revealed that VA elevated PGC-1αmRNA and protein contents,and enhanced the level of p38 MAPK phosphorylation in LD muscle of sheep.In addition,the number of type I myofibers with RA treatment was significantly increased,and type IIx myofibers was significantly decreased in primary myoblasts.Consistent with in vivo experiment,RA significantly improved mitochondrial biogenesis and function in primary myoblasts of sheep.We then used si-PGC-1αto inhibit PGC-1αexpression and found that si-PGC-1αsignificantly abrogated RA-induced the formation of type I myofibers,mitochondrial biogenesis,MitoTracker staining intensity,UQCRC1 and ATP5A1 expression,SDH activity,and enhanced the level of type IIx muscle fibers.These data suggested that RA improved mitochondrial biogenesis and function by promoting PGC-1αexpression,and increased type I myofibers.In order to prove that the effect of RA on the level of PGC-1αis caused by p38 MAPK signaling,we inhibited the p38 MAPK signaling using a p38 MAPK inhibitor,which significantly reduced RA-induced PGC-1αand MyHC I levels.Conclusion VA promoted PGC-1αexpression through the p38 MAPK signaling pathway,improved mitochondrial biogenesis,and altered the composition of muscle fiber type.
文摘目的研究麻杏解毒合剂对冠状病毒肺炎模型小鼠炎性因子表达的影响,基于p38MAPK/AP-1通路研究其疗效机制。方法60只昆明种(KM)小鼠随机分成空白对照组、模型组、p38MAPK抑制剂组及麻杏解毒合剂高、中、低剂量组,每组10只。采用模拟寒湿环境、表达h ACE2的重组腺相关病毒转导、SARS-CoV-2spike假病毒气管内给药建立小鼠冠状病毒肺炎模型。检测各组小鼠血清炎性因子、肺组织病理改变、肺组织p38MAPK、c-jun、c-fos的mRNA水平和蛋白表达情况。结果与空白对照组比较,模型组小鼠血清炎性因子白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)、白细胞介素-8(IL-8)、肿瘤坏死因子-α(TNF-α)的表达均显著升高(P<0.01),肺组织炎性改变明显,c-fos m RNA水平和p-p38、c-fos、c-jun蛋白表达均显著增加(P<0.05)。与模型组比较,麻杏解毒合剂高、中剂量组小鼠血清炎性因子显著降低(P<0.01或P<0.05),小鼠肺组织炎性损伤明显减轻,同时肺组织中c-fos的mRNA水平和p-p38、c-fos的蛋白表达均显著下调(P<0.05)。结论麻杏解毒合剂能降低病毒性肺炎模型小鼠血清炎性因子水平,减轻肺组织炎性损伤,其疗效机制与抑制p38MAPK蛋白的磷酸化,下调AP-1通路mRNA及蛋白表达有关。
