Appropriate autophagy has protective effects on ischemic nerve tissue,while excessive autophagy may cause cell death.The inflammatory response plays an important role in the survival of nerve cells and the recovery of...Appropriate autophagy has protective effects on ischemic nerve tissue,while excessive autophagy may cause cell death.The inflammatory response plays an important role in the survival of nerve cells and the recovery of neural tissue after ischemia.Many studies have found an interaction between autophagy and inflammation in the pathogenesis of ischemic stroke.This study outlines recent advances regarding the role of autophagy in the post-stroke inflammatory response as follows.(1)Autophagy inhibits inflammatory responses caused by ischemic stimulation through mTOR,the AMPK pathway,and inhibition of inflammasome activation.(2)Activation of inflammation triggers the formation of autophagosomes,and the upregulation of autophagy levels is marked by a significant increase in the autophagy-forming markers LC3-II and Beclin-1.Lipopolysaccharide stimulates microglia and inhibits ULK1 activity by direct phosphorylation of p38 MAPK,reducing the flux and autophagy level,thereby inducing inflammatory activity.(3)By blocking the activation of autophagy,the activation of inflammasomes can alleviate cerebral ischemic injury.Autophagy can also regulate the phenotypic alternation of microglia through the nuclear factor-κB pathway,which is beneficial to the recovery of neural tissue after ischemia.Studies have shown that some drugs such as resveratrol can exert neuroprotective effects by regulating the autophagy-inflammatory pathway.These studies suggest that the autophagy-inflammatory pathway may provide a new direction for the treatment of ischemic stroke.展开更多
Background Baicalin has a significant anti-inflammation effect and is widely used in the clinical treatment of stroke. Most of the studies of Toll-like receptor 2/4 （TLR2/4） during cerebral ischemia had defined the...Background Baicalin has a significant anti-inflammation effect and is widely used in the clinical treatment of stroke. Most of the studies of Toll-like receptor 2/4 （TLR2/4） during cerebral ischemia had defined their specific expressions in microglia in hippocampus tissue. To explore the targets of baicalin in stroke, we detected the expressions of TLR2/4 in vitro/vivo.Methods By constructing a cerebral ischemia-reperfusion model in vivo and glucose oxygen deprivation model, we successfully induced neuron damage, then added baicalin and detected expressions of TLR2/4, nuclear factor-kB （NF-kB）, tumor necrosis factor-alpha （TNFα）, and interleukin-1β （IL-1β） in mRNA level and protein level.Results We found distinct upregulations of TLR2/4 and TNFα in both mRNA level and protein level in PC12 cells and primary neurons. Moreover, TLR2/4 and TNFα expressions were significantly higher in mice hippocampus treated with cerebral ischemia-reperfusion. Baicalin could downregulate the expressions of TLR2/4 and TNFα in the damaged cells and mice hippocampus effectively.Conclusions Neurons could respond to the damage and activate the related signal pathway directly. TLR2/4 responsed to the damage and sent the signal to downstream factor TNFα through activating NF-kB. Baicalin could inhibit the inflammatory reaction in neuron damage and TLR might be its targets, which explained why baicalin could widely be used in the clinical treatment of stroke.展开更多
Penehyclidine hydrochloride can promote microcirculation and reduce vascular permeability. However, the role of penehyclidine hydrochlodde in cerebral ischemia-reperfusion injury remains unclear. In this study, in viv...Penehyclidine hydrochloride can promote microcirculation and reduce vascular permeability. However, the role of penehyclidine hydrochlodde in cerebral ischemia-reperfusion injury remains unclear. In this study, in vivo middle cerebral artery occlusion models were established in experimental rats, and penehyclidine hydrochloride pretreatment was given via intravenous injection prior to model establishment. Tetrazolium chloride, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling and immunohistochemical staining showed that, penehyclidine hydrochloride pretreatment markedly attenuated neuronal histopathological changes in the cortex, hippocampus and striatum, reduced infarction size, increased the expression level of BcI-2, decreased the expression level of caspase-3, and inhibited neuronal apoptosis in rats with cerebral ischemia-reperfusion injury. Xanthine oxidase and thiobarbituric acid chromogenic results showed that penehyclidine hydrochloride upregulated the activity of superoxide dismutase and downregulated the concentration of malondialdehyde in the ischemic cerebral cortex and hippocampus, as well as reduced the concentration of extracellular excitatory amino acids in rats with cerebral ischemia-reperfusion injury. In addition, penehyclidine hydrochloride inhibited the expression level of the NR1 subunit in hippocampal nerve cells in vitro following oxygen-glucose deprivation, as detected by PCR. Experimental findings indicate that penehyclidine hydrochloride attenuates neuronal apoptosis and oxidative stress injury after focal cerebral ischemia-reperfusion, thus exerting a neuroprotective effect.展开更多
Transplantation of human bone marrow mesenchymal stem cells(hMSCs) stands as a potent stroke therapy, but its exact mechanism remains unknown. This study investigated the anti-apoptotic mechanisms by which hMSCs exert...Transplantation of human bone marrow mesenchymal stem cells(hMSCs) stands as a potent stroke therapy, but its exact mechanism remains unknown. This study investigated the anti-apoptotic mechanisms by which hMSCs exert neuroprotective effects on cerebral ischemia. Primary mixed cultures of rat neurons and astrocytes were cultured and exposed to oxygen-glucose deprivation. A two-hour period of "reperfusion" in standard medium and normoxic conditions was allowed and immediately followed by hMSCs and/or Bcl-2 antibody treatment. Cell viability of primary rat neurons and astrocytes was determined by 3-(4,5-dimethylthianol-2-yl)-2,5 diphenyl tetrazolium bromide and trypan blue exclusion methods. hMSC survival and differentiation were characterized by immunocytochemistry, while the concentration of Bcl-2 in the supernatant was measured by enzyme-linked immunosorbent assay to reveal the secretory anti-apoptotic function of hMSCs. Cultured hMSCs expressed embryonic-like stem cell phenotypic markers CXCR4, Oct4, SSEA4, and Nanog, as well as immature neural phenotypic marker Nestin. Primary rat neurons and astrocytes were protected from oxygen-glucose deprivation by hMSCs, which was antagonized by the Bcl-2 antibody. However, Bcl-2 levels in the supernatants did not differ between hMSCand non-treated cells exposed to oxygen-glucose deprivation. Neuroprotective effects of hMSCs against cerebral ischemia were partially mediated by the anti-apoptotic mechanisms. However, further studies are warranted to fully elucidate this pathway.展开更多
基金supported by the Natural Science Foundation of Shanghai of China,No.17ZR1425800(to KYL)the Shanghai Pudong District Health Bureau of China,No.PDZX2017-25(to KYL)
文摘Appropriate autophagy has protective effects on ischemic nerve tissue,while excessive autophagy may cause cell death.The inflammatory response plays an important role in the survival of nerve cells and the recovery of neural tissue after ischemia.Many studies have found an interaction between autophagy and inflammation in the pathogenesis of ischemic stroke.This study outlines recent advances regarding the role of autophagy in the post-stroke inflammatory response as follows.(1)Autophagy inhibits inflammatory responses caused by ischemic stimulation through mTOR,the AMPK pathway,and inhibition of inflammasome activation.(2)Activation of inflammation triggers the formation of autophagosomes,and the upregulation of autophagy levels is marked by a significant increase in the autophagy-forming markers LC3-II and Beclin-1.Lipopolysaccharide stimulates microglia and inhibits ULK1 activity by direct phosphorylation of p38 MAPK,reducing the flux and autophagy level,thereby inducing inflammatory activity.(3)By blocking the activation of autophagy,the activation of inflammasomes can alleviate cerebral ischemic injury.Autophagy can also regulate the phenotypic alternation of microglia through the nuclear factor-κB pathway,which is beneficial to the recovery of neural tissue after ischemia.Studies have shown that some drugs such as resveratrol can exert neuroprotective effects by regulating the autophagy-inflammatory pathway.These studies suggest that the autophagy-inflammatory pathway may provide a new direction for the treatment of ischemic stroke.
基金This work was supported by grants from the National Natural Science Foundation of China （No. 30973896, No. 30801523, and No. 81073092） and the National S＆T Major Special Project for New Drug R＆D Program of China （No. 2009ZX09103-301, No. 2009ZX09502, No. 2009ZX09308-003, and No. 2011ZX09101- 002-11）.Acknowledgments： We thank specially all our colleagues in our laboratory.
文摘Background Baicalin has a significant anti-inflammation effect and is widely used in the clinical treatment of stroke. Most of the studies of Toll-like receptor 2/4 （TLR2/4） during cerebral ischemia had defined their specific expressions in microglia in hippocampus tissue. To explore the targets of baicalin in stroke, we detected the expressions of TLR2/4 in vitro/vivo.Methods By constructing a cerebral ischemia-reperfusion model in vivo and glucose oxygen deprivation model, we successfully induced neuron damage, then added baicalin and detected expressions of TLR2/4, nuclear factor-kB （NF-kB）, tumor necrosis factor-alpha （TNFα）, and interleukin-1β （IL-1β） in mRNA level and protein level.Results We found distinct upregulations of TLR2/4 and TNFα in both mRNA level and protein level in PC12 cells and primary neurons. Moreover, TLR2/4 and TNFα expressions were significantly higher in mice hippocampus treated with cerebral ischemia-reperfusion. Baicalin could downregulate the expressions of TLR2/4 and TNFα in the damaged cells and mice hippocampus effectively.Conclusions Neurons could respond to the damage and activate the related signal pathway directly. TLR2/4 responsed to the damage and sent the signal to downstream factor TNFα through activating NF-kB. Baicalin could inhibit the inflammatory reaction in neuron damage and TLR might be its targets, which explained why baicalin could widely be used in the clinical treatment of stroke.
文摘Penehyclidine hydrochloride can promote microcirculation and reduce vascular permeability. However, the role of penehyclidine hydrochlodde in cerebral ischemia-reperfusion injury remains unclear. In this study, in vivo middle cerebral artery occlusion models were established in experimental rats, and penehyclidine hydrochloride pretreatment was given via intravenous injection prior to model establishment. Tetrazolium chloride, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling and immunohistochemical staining showed that, penehyclidine hydrochloride pretreatment markedly attenuated neuronal histopathological changes in the cortex, hippocampus and striatum, reduced infarction size, increased the expression level of BcI-2, decreased the expression level of caspase-3, and inhibited neuronal apoptosis in rats with cerebral ischemia-reperfusion injury. Xanthine oxidase and thiobarbituric acid chromogenic results showed that penehyclidine hydrochloride upregulated the activity of superoxide dismutase and downregulated the concentration of malondialdehyde in the ischemic cerebral cortex and hippocampus, as well as reduced the concentration of extracellular excitatory amino acids in rats with cerebral ischemia-reperfusion injury. In addition, penehyclidine hydrochloride inhibited the expression level of the NR1 subunit in hippocampal nerve cells in vitro following oxygen-glucose deprivation, as detected by PCR. Experimental findings indicate that penehyclidine hydrochloride attenuates neuronal apoptosis and oxidative stress injury after focal cerebral ischemia-reperfusion, thus exerting a neuroprotective effect.
基金Cesar V.Borlongan was funded by NIH R01NS071956,NIH R01 NS090962,NIH R21NS089851,NIH R21 NS094087VA Merit Review I01 BX001407
文摘Transplantation of human bone marrow mesenchymal stem cells(hMSCs) stands as a potent stroke therapy, but its exact mechanism remains unknown. This study investigated the anti-apoptotic mechanisms by which hMSCs exert neuroprotective effects on cerebral ischemia. Primary mixed cultures of rat neurons and astrocytes were cultured and exposed to oxygen-glucose deprivation. A two-hour period of "reperfusion" in standard medium and normoxic conditions was allowed and immediately followed by hMSCs and/or Bcl-2 antibody treatment. Cell viability of primary rat neurons and astrocytes was determined by 3-(4,5-dimethylthianol-2-yl)-2,5 diphenyl tetrazolium bromide and trypan blue exclusion methods. hMSC survival and differentiation were characterized by immunocytochemistry, while the concentration of Bcl-2 in the supernatant was measured by enzyme-linked immunosorbent assay to reveal the secretory anti-apoptotic function of hMSCs. Cultured hMSCs expressed embryonic-like stem cell phenotypic markers CXCR4, Oct4, SSEA4, and Nanog, as well as immature neural phenotypic marker Nestin. Primary rat neurons and astrocytes were protected from oxygen-glucose deprivation by hMSCs, which was antagonized by the Bcl-2 antibody. However, Bcl-2 levels in the supernatants did not differ between hMSCand non-treated cells exposed to oxygen-glucose deprivation. Neuroprotective effects of hMSCs against cerebral ischemia were partially mediated by the anti-apoptotic mechanisms. However, further studies are warranted to fully elucidate this pathway.
