We have previously demonstrated that acute treatment with low dose methamphetamine is neuroprotectivein a rat model of severe traumatic brain injury (TBI). Using gene expression analysis, we further showed that metham...We have previously demonstrated that acute treatment with low dose methamphetamine is neuroprotectivein a rat model of severe traumatic brain injury (TBI). Using gene expression analysis, we further showed that methamphetamine treatment significantly reduced the expression of pro-inflammatory genes after severe TBI. Therefore, to further investigate the potential effects of methamphetamine treatment on the neuroinflammatory response, we examined immunofluorescent staining of Iba1 and CD68, two marker of neuroinflammation, in the rat lateral fluid percussion injury model of severe TBI. In this study, we observed temporal and spatial alterations in the pattern of Iba1 and CD68 labeling within two weeks after severe TBI. In general, methamphetamine treatment did not dramatically alter the pattern of Iba1 and CD68 staining. However, we did observe a unique and significant drug-induced increase of Iba1 labeling within the granule cell layer of the dentate gyrusat 48 hours post injury. We also observed rod-shaped Iba1+?cells within the core lesion in the cortex. These cells showed variable staining with CD68 and aligned most closely with MAP2+?neuronal processes. Thus, acute treatment with low-dose methamphetamine after severe TBI caused a transient bilateral increase of Iba1+?cells within the granule layer of the dentate gyrus but did not alter the overall temporal and regional pattern of Iba1 and CD68 staining within the cortex, periventricular white matter, fimbria, or thalamus.展开更多
Microglia, as the resident immune cells in the central nervous system, play important roles in regulating neuronal processes, such as neural excitability, synaptic activity, and apoptotic cell clearance. Growth factor...Microglia, as the resident immune cells in the central nervous system, play important roles in regulating neuronal processes, such as neural excitability, synaptic activity, and apoptotic cell clearance. Growth factors can activate multiple signaling pathways in central nervous system microglia and can regulate their immune effects, but whether growth factors can affect the morphological characteristics and ultrastructure of microglia has not been reported. After microinjecting 300 nL of a growth factor cocktail, including 10 μg/mL epidermal growth factor, 10 μg/mL basic fibroblast growth factor, 10 μg/mL hepatocyte growth factor and 10 μg/mL insulin-like growth factor into adult rat cortex, we found that the number of IBA1-positive microglia around the injection area increased significantly, indicating local activation of microglia. All CD68-positive labeling co-localized with IBA1 in microglia. Cell bodies and protrusions of CD68-positive cells were strongly attached to or were engulfing neurons. Characteristic huge phagosomes were observed in activated phagocytes by electron microscopy. The phagosomes generally included non-degraded neuronal protrusions and mitochondria, yet they contained no myelin membrane or remnants, which might indicate selective phagocytosis by the phagocytes. The remnant myelin sheath after phagocytosis still had regenerative ability and formed "myelin-like" structures around phagocytes. These results show that microinjection of a growth factor cocktail into the cerebral cortex of rodents can locally activate microglia and induce selective phagocytosis of neural structures by phagocytes. The study was approved by the Institute of Laboratory Animal Science, Beijing Institute of Basic Medical Sciences(approval No. IACUC-AMMS-2014-501) on June 30, 2014.展开更多
Ischemic brain injury causes neuronal death and inflammation.Inflammation activates protein-tyrosine phosphatase 1B(PTP1B).Here,we tested the significance of PTP1B activation in glutamatergic projection neurons on fun...Ischemic brain injury causes neuronal death and inflammation.Inflammation activates protein-tyrosine phosphatase 1B(PTP1B).Here,we tested the significance of PTP1B activation in glutamatergic projection neurons on functional recovery in two models of stroke:by photothrombosis,focal ischemic lesions were induced in the sensorimotor cortex(SM stroke)or in the peri-prefrontal cortex(peri-PFC stroke).Elevated PTP1B expression was detected at 4 days and up to 6 weeks after stroke.While ablation of PTP1B in neurons of neuronal knockout(NKO)mice had no effect on the volume or resorption of ischemic lesions,markedly different effects on functional recovery were observed.SM stroke caused severe sensory and motor deficits(adhesive removal test)in wild type and NKO mice at 4 days,but NKO mice showed drastically improved sensory and motor functional recovery at 8 days.In addition,peri-PFC stroke caused anxiety-like behaviors(elevated plus maze and open field tests),and depression-like behaviors(forced swimming and tail suspension tests)in wild type mice 9 and 28 days after stroke,respectively,with minimal effect on sensory and motor function.Peri-PFC stroke-induced affective disorders were associated with fewer active(FosB+)neurons in the PFC and nucleus accumbens but more FosB+neurons in the basolateral amygdala,compared to sham-operated mice.In contrast,mice with neuronal ablation of PTP1B were protected from anxiety-like and depression-like behaviors and showed no change in FosB+neurons after peri-PFC stroke.Taken together,our study identifies neuronal PTP1B as a key component that hinders sensory and motor functional recovery and also contributes to the development of anxiety-like and depression-like behaviors after stroke.Thus,PTP1B may represent a novel therapeutic target to improve stroke recovery.All procedures for animal use were approved by the Animal Care and Use Committee of the University of Ottawa Animal Care and Veterinary Service(protocol 1806)on July 27,2018.展开更多
文摘We have previously demonstrated that acute treatment with low dose methamphetamine is neuroprotectivein a rat model of severe traumatic brain injury (TBI). Using gene expression analysis, we further showed that methamphetamine treatment significantly reduced the expression of pro-inflammatory genes after severe TBI. Therefore, to further investigate the potential effects of methamphetamine treatment on the neuroinflammatory response, we examined immunofluorescent staining of Iba1 and CD68, two marker of neuroinflammation, in the rat lateral fluid percussion injury model of severe TBI. In this study, we observed temporal and spatial alterations in the pattern of Iba1 and CD68 labeling within two weeks after severe TBI. In general, methamphetamine treatment did not dramatically alter the pattern of Iba1 and CD68 staining. However, we did observe a unique and significant drug-induced increase of Iba1 labeling within the granule cell layer of the dentate gyrusat 48 hours post injury. We also observed rod-shaped Iba1+?cells within the core lesion in the cortex. These cells showed variable staining with CD68 and aligned most closely with MAP2+?neuronal processes. Thus, acute treatment with low-dose methamphetamine after severe TBI caused a transient bilateral increase of Iba1+?cells within the granule layer of the dentate gyrus but did not alter the overall temporal and regional pattern of Iba1 and CD68 staining within the cortex, periventricular white matter, fimbria, or thalamus.
基金supported by a grant from State Key Laboratory of Proteomics of China,No.SKLP-K201401(to SJL)the National Key Project of Basic Research of China,No.2009CB918301(to SJL)the National Natural Science Foundation of China,Nos.30430310,30140001,30370460(to SJL)
文摘Microglia, as the resident immune cells in the central nervous system, play important roles in regulating neuronal processes, such as neural excitability, synaptic activity, and apoptotic cell clearance. Growth factors can activate multiple signaling pathways in central nervous system microglia and can regulate their immune effects, but whether growth factors can affect the morphological characteristics and ultrastructure of microglia has not been reported. After microinjecting 300 nL of a growth factor cocktail, including 10 μg/mL epidermal growth factor, 10 μg/mL basic fibroblast growth factor, 10 μg/mL hepatocyte growth factor and 10 μg/mL insulin-like growth factor into adult rat cortex, we found that the number of IBA1-positive microglia around the injection area increased significantly, indicating local activation of microglia. All CD68-positive labeling co-localized with IBA1 in microglia. Cell bodies and protrusions of CD68-positive cells were strongly attached to or were engulfing neurons. Characteristic huge phagosomes were observed in activated phagocytes by electron microscopy. The phagosomes generally included non-degraded neuronal protrusions and mitochondria, yet they contained no myelin membrane or remnants, which might indicate selective phagocytosis by the phagocytes. The remnant myelin sheath after phagocytosis still had regenerative ability and formed "myelin-like" structures around phagocytes. These results show that microinjection of a growth factor cocktail into the cerebral cortex of rodents can locally activate microglia and induce selective phagocytosis of neural structures by phagocytes. The study was approved by the Institute of Laboratory Animal Science, Beijing Institute of Basic Medical Sciences(approval No. IACUC-AMMS-2014-501) on June 30, 2014.
基金This work was supported by grants from the Heart and Stroke Foundation of Canada(Nos.G-13-0002596&G-18-0022157,to HHCNo.G-16-00014085,to AFRS)+2 种基金the Natural Science and Engineering Research Council of Canada(No.RGPIN/06212-2014,to HHC,No.RGPIN/2016-04985,to AFRS)the Canadian Institutes of Health Research(No.201610PJT,to HHC)HHC is also supported by a Mid-Career Investigator Award(No.7506)from the Heart and Stroke Foundation of Ontario.How to cite this article:Cruz SA。
文摘Ischemic brain injury causes neuronal death and inflammation.Inflammation activates protein-tyrosine phosphatase 1B(PTP1B).Here,we tested the significance of PTP1B activation in glutamatergic projection neurons on functional recovery in two models of stroke:by photothrombosis,focal ischemic lesions were induced in the sensorimotor cortex(SM stroke)or in the peri-prefrontal cortex(peri-PFC stroke).Elevated PTP1B expression was detected at 4 days and up to 6 weeks after stroke.While ablation of PTP1B in neurons of neuronal knockout(NKO)mice had no effect on the volume or resorption of ischemic lesions,markedly different effects on functional recovery were observed.SM stroke caused severe sensory and motor deficits(adhesive removal test)in wild type and NKO mice at 4 days,but NKO mice showed drastically improved sensory and motor functional recovery at 8 days.In addition,peri-PFC stroke caused anxiety-like behaviors(elevated plus maze and open field tests),and depression-like behaviors(forced swimming and tail suspension tests)in wild type mice 9 and 28 days after stroke,respectively,with minimal effect on sensory and motor function.Peri-PFC stroke-induced affective disorders were associated with fewer active(FosB+)neurons in the PFC and nucleus accumbens but more FosB+neurons in the basolateral amygdala,compared to sham-operated mice.In contrast,mice with neuronal ablation of PTP1B were protected from anxiety-like and depression-like behaviors and showed no change in FosB+neurons after peri-PFC stroke.Taken together,our study identifies neuronal PTP1B as a key component that hinders sensory and motor functional recovery and also contributes to the development of anxiety-like and depression-like behaviors after stroke.Thus,PTP1B may represent a novel therapeutic target to improve stroke recovery.All procedures for animal use were approved by the Animal Care and Use Committee of the University of Ottawa Animal Care and Veterinary Service(protocol 1806)on July 27,2018.
