Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells ...Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling,influencing their activation such that they can promote neurological recovery.However,the mechanism of CXCR4 upregulation in induced neural stem cells remains unclear.In this study,we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-αexpression but suppressed insulin-like growth factor-1 expression.However,recombinant complement receptor 2-conjugated Crry(CR2-Crry)reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia,CXCL12,and tumor necrosis factor-α.Additionally,we observed that,in response to stimulation(including stimulation by CXCL12 secreted by activated microglia),CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4,Crry,and Akt signaling to modulate microglial activation.In agreement with these in vitro experimental results,we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation,leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury mice.Notably,these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury,cerebral edema,and neurological disorders post–closed head injury.In conclusion,our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neural stem cells on microglial activation via upregulation of CXCR4 and Crry,thereby promoting induced neural stem cell–mediated improvement of neuronal injury,cerebral edema,and neurological disorders following closed head injury.展开更多
Complement component(3b/4b)receptor 1(CR1)expression is positively related to the abundance of phosphorylated microtubule-associated protein tau(tau),and CR1 expression is associated with susceptibility to Alzheimer’...Complement component(3b/4b)receptor 1(CR1)expression is positively related to the abundance of phosphorylated microtubule-associated protein tau(tau),and CR1 expression is associated with susceptibility to Alzheimer’s disease.However,the exact role of CR1 in tau protein-associated neurodegenerative diseases is unknown.In this study,we show that the mouse Cr1-related protein Y(Crry)gene,Crry,is localized to microglia.We also found that Crry protein expression in the hippocampus and cortex was significantly elevated in P301S mice(a mouse model widely used for investigating tau pathology)compared with that in wild-type mice.Tau protein phosphorylation(at serine 202,threonine 205,threonine 231,and serine 262)and expression of the major tau kinases glycogen synthase kinase-3 beta and cyclin-dependent-like kinase 5 were greater in P301S mice than in wild-type mice.Crry silencing by lentivirus-transfected short hairpin RNA led to greatly reduced tau phosphorylation and glycogen synthase kinase-3 beta and cyclin-dependent-like kinase 5 activity.Crry silencing reduced neuronal apoptosis and rescued cognitive impairment of P301S mice.Crry silencing also reduced the levels of the neuroinflammatory factors interleukin-1 beta,tumor necrosis factor alpha,and interleukin-6 and the complement components complement 3 and complement component 3b.Our results suggest that Crry silencing in the P301S mouse model reduces tau protein phosphorylation by reducing the levels of neuroinflammation and complement components,thereby improving cognitive function.展开更多
基金supported by the National Natural Science Foundation of China,Nos.82271397(to MG),82001293(to MG),82171355(to RX),81971295(to RX),and 81671189(to RX)。
文摘Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling,influencing their activation such that they can promote neurological recovery.However,the mechanism of CXCR4 upregulation in induced neural stem cells remains unclear.In this study,we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-αexpression but suppressed insulin-like growth factor-1 expression.However,recombinant complement receptor 2-conjugated Crry(CR2-Crry)reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia,CXCL12,and tumor necrosis factor-α.Additionally,we observed that,in response to stimulation(including stimulation by CXCL12 secreted by activated microglia),CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4,Crry,and Akt signaling to modulate microglial activation.In agreement with these in vitro experimental results,we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation,leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury mice.Notably,these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury,cerebral edema,and neurological disorders post–closed head injury.In conclusion,our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neural stem cells on microglial activation via upregulation of CXCR4 and Crry,thereby promoting induced neural stem cell–mediated improvement of neuronal injury,cerebral edema,and neurological disorders following closed head injury.
基金supported by the National Natural Science Foundation of China(No.81801054)the Natural Science Foundation of Jiangsu Province of China(No.BK20180166)+2 种基金the Wuxi Municipal Health and Family Planning Commission Fund of China(No.Q201722)Wuxi Top Talent Support Program for Young and Middle-aged People of Wuxi Health Committee of China(No.HB2020023)China Postdoctoral Funding(all to XCZ).
文摘Complement component(3b/4b)receptor 1(CR1)expression is positively related to the abundance of phosphorylated microtubule-associated protein tau(tau),and CR1 expression is associated with susceptibility to Alzheimer’s disease.However,the exact role of CR1 in tau protein-associated neurodegenerative diseases is unknown.In this study,we show that the mouse Cr1-related protein Y(Crry)gene,Crry,is localized to microglia.We also found that Crry protein expression in the hippocampus and cortex was significantly elevated in P301S mice(a mouse model widely used for investigating tau pathology)compared with that in wild-type mice.Tau protein phosphorylation(at serine 202,threonine 205,threonine 231,and serine 262)and expression of the major tau kinases glycogen synthase kinase-3 beta and cyclin-dependent-like kinase 5 were greater in P301S mice than in wild-type mice.Crry silencing by lentivirus-transfected short hairpin RNA led to greatly reduced tau phosphorylation and glycogen synthase kinase-3 beta and cyclin-dependent-like kinase 5 activity.Crry silencing reduced neuronal apoptosis and rescued cognitive impairment of P301S mice.Crry silencing also reduced the levels of the neuroinflammatory factors interleukin-1 beta,tumor necrosis factor alpha,and interleukin-6 and the complement components complement 3 and complement component 3b.Our results suggest that Crry silencing in the P301S mouse model reduces tau protein phosphorylation by reducing the levels of neuroinflammation and complement components,thereby improving cognitive function.
