Exposure to chronic hypoxia is considered to be a risk factor for deficits in brain function in adults,but the underlying mechanisms remain largely unknown.Since active myelinogenesis persists in the adult central ner...Exposure to chronic hypoxia is considered to be a risk factor for deficits in brain function in adults,but the underlying mechanisms remain largely unknown.Since active myelinogenesis persists in the adult central nervous system,here we aimed to investigate the impact of chronic hypoxia on myelination and the related functional consequences in adult mice.Using a transgenic approach to label newly-generated myelin sheaths(NG2-CreER^(TM);Tau-mGFP),we found that myelinogenesis was highly active in most brain regions,such as the motor cortex and corpus callosum.After exposure to hypoxia(10%oxygen)12 h per day for 4 weeks,myelinogenesis was largely inhibited in the 4-month old brain and the mice displayed motor coordination deficits revealed by the beam-walking test.To determine the relationship between the inhibited myelination and functional impairment,we induced oligoden-droglia-specific deletion of the transcription factor 01ig2 by tamoxifen(NG2-CreER^(TM);Tau-mGFP;Olig2 fl/fl)in adult mice to mimic the decreased myelinogenesis caused by hypoxia.The deletion of OHg2 inhibited myelinogenesis and consequently impaired motor coordination,suggesting that myelinogenesis is required for motor function in adult mice.To understand whether enhancing myelination could protect brain functions against hypoxia,we treated hypoxic mice with the myelination-enhancing drug-clemastine,which resulted in enhanced myelogenesis and improved motor coordination.Taken together,our data indicate that chronic hypoxia inhibits myelinogenesis and causes functional deficits in the brain and that enhancing myelinogenesis protects brain functions against hypoxia-related deficits.展开更多
The molecular and cellular mechanisms by which alcohol produces its deleterious effects on neuronal networks are only now beginning to be understood. This review focused on alcohol-induced neurobiological alterations ...The molecular and cellular mechanisms by which alcohol produces its deleterious effects on neuronal networks are only now beginning to be understood. This review focused on alcohol-induced neurobiological alterations on neuronal network components underlying information processing, for further understanding of intellectual disability related to FASD. Abnormal neurodevelopmental events related to alcohol-damaged fetal brain included neurogenesis inhibition, aberrant migration, impaired differentiation, exacerbated apoptosis, impaired axon outgrowth and branching altering synaptogenesis and synaptic plasticity, abnormal GABAergic interneurons triggering synaptic inhibitory/excitatory imbalance, reduced myelinogenesis causing injured white matter in prefrontal lobe and atrophied corpus callosum compromising interhemispheric information transfer, the whole compromising neuronal network scaffolding which may lead to biased information processing with deficits in executive function. What added to these abnormalities are smaller gray matter and reduced hippocampus, resulting in cognition and memory failures. As a whole, these developmental disorders may underlie intellectual disability related to FASD. In rodents, these neuronal network components matured mainly during the second and third trimesters equivalents of human gestation. Transferability of results from animal to human was also discussed. It was hoped that the understanding of alcohol-induced neuronal networks failure mechanisms during the developing brain may lay a foundation for prospective new treatments and interventions.展开更多
基金by grants from the National Natural Science Foundation of China(32000723)Chongqing Education Commission Fund(CXQT19009)+3 种基金Chongqing Outstanding Young Investigator Fund(cstc2019jcyjjqx0001)the Natural Science Foundation of Chongqing(cstc2017jcyjAX0365)the Army Medical University Natural Science Fund(31041455)the Open Project Program of the Brain and Intelligence Research Key Laboratory of Chongqing Education Commission of China(BIR2019004).
文摘Exposure to chronic hypoxia is considered to be a risk factor for deficits in brain function in adults,but the underlying mechanisms remain largely unknown.Since active myelinogenesis persists in the adult central nervous system,here we aimed to investigate the impact of chronic hypoxia on myelination and the related functional consequences in adult mice.Using a transgenic approach to label newly-generated myelin sheaths(NG2-CreER^(TM);Tau-mGFP),we found that myelinogenesis was highly active in most brain regions,such as the motor cortex and corpus callosum.After exposure to hypoxia(10%oxygen)12 h per day for 4 weeks,myelinogenesis was largely inhibited in the 4-month old brain and the mice displayed motor coordination deficits revealed by the beam-walking test.To determine the relationship between the inhibited myelination and functional impairment,we induced oligoden-droglia-specific deletion of the transcription factor 01ig2 by tamoxifen(NG2-CreER^(TM);Tau-mGFP;Olig2 fl/fl)in adult mice to mimic the decreased myelinogenesis caused by hypoxia.The deletion of OHg2 inhibited myelinogenesis and consequently impaired motor coordination,suggesting that myelinogenesis is required for motor function in adult mice.To understand whether enhancing myelination could protect brain functions against hypoxia,we treated hypoxic mice with the myelination-enhancing drug-clemastine,which resulted in enhanced myelogenesis and improved motor coordination.Taken together,our data indicate that chronic hypoxia inhibits myelinogenesis and causes functional deficits in the brain and that enhancing myelinogenesis protects brain functions against hypoxia-related deficits.
文摘The molecular and cellular mechanisms by which alcohol produces its deleterious effects on neuronal networks are only now beginning to be understood. This review focused on alcohol-induced neurobiological alterations on neuronal network components underlying information processing, for further understanding of intellectual disability related to FASD. Abnormal neurodevelopmental events related to alcohol-damaged fetal brain included neurogenesis inhibition, aberrant migration, impaired differentiation, exacerbated apoptosis, impaired axon outgrowth and branching altering synaptogenesis and synaptic plasticity, abnormal GABAergic interneurons triggering synaptic inhibitory/excitatory imbalance, reduced myelinogenesis causing injured white matter in prefrontal lobe and atrophied corpus callosum compromising interhemispheric information transfer, the whole compromising neuronal network scaffolding which may lead to biased information processing with deficits in executive function. What added to these abnormalities are smaller gray matter and reduced hippocampus, resulting in cognition and memory failures. As a whole, these developmental disorders may underlie intellectual disability related to FASD. In rodents, these neuronal network components matured mainly during the second and third trimesters equivalents of human gestation. Transferability of results from animal to human was also discussed. It was hoped that the understanding of alcohol-induced neuronal networks failure mechanisms during the developing brain may lay a foundation for prospective new treatments and interventions.
