Adolescent alcohol abuse is a substantive public health problem that has been the subject of intensive study in recent years.Despite reports of a wide range of effects of adolescent intermittent ethanol(AIE)exposure o...Adolescent alcohol abuse is a substantive public health problem that has been the subject of intensive study in recent years.Despite reports of a wide range of effects of adolescent intermittent ethanol(AIE)exposure on brain and behavior,little is known about the mechanisms that may underlie those effects,and even less about treatments that might reverse them.Recent studies from our laboratory have indicated that AIE produced enduring changes in astrocyte function and synaptic activity in the hippocampal formation,suggesting the possibility of an alteration in astrocyte-neuronal connectivity and function.We utilized astrocyte-specific,membrane restricted viral labeling paired with immunohistochemistry to perform confocal single cell astrocyte imaging,three-dimensional reconstruction,and quantification of astrocyte morphology in hippocampal area CA1 from adult rats after AIE.Additionally,we assessed the colocalization of astrocyte plasma membrane labeling with immunoreactivity for AMPA-(α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid)glutamate receptor 1,an AMPA receptor subunit and established neuronal marker of excitatory synapses,as a metric of astrocyte-synapse proximity.AIE significantly reduced the colocalization of the astrocyte plasma membrane with synaptic marker puncta in adulthood.This is striking in that it suggests not only an alteration of the physical association of astrocytes with synapses by AIE,but one that lasts into adulthood-well after the termination of alcohol exposure.Perhaps even more notable,the AIE-induced reduction of astrocyte-synapse interaction was reversed by sub-chronic treatment with the clinically used agent,gabapentin(Neurontin),in adulthood.This suggests that a medication in common clinical use may have the potential to reverse some of the enduring effects of adolescent alcohol exposure on brain function.All animal experiments conducted were approved by the Duke University Institutional Animal Care and Use Committee(Protocol Registry Number A159-18-07)on July 27,2018.展开更多
Stress is a major risk factor for the development of mental illness,such as major depression disorder (MDD)[1].Despite decades of progress,including findings that stressinduced depression corresponds with numerous mor...Stress is a major risk factor for the development of mental illness,such as major depression disorder (MDD)[1].Despite decades of progress,including findings that stressinduced depression corresponds with numerous morphological and functional neuronal changes within brain structures associated with cognition and mood,such as the medial prefrontal cortex (mPFC)[1-3],a thorough understanding of how stress induces the core symptoms of depression,such as hopelessness,is still lacking.In an exciting new paper in mice,Yin et al.show that astrocyteneuronal metabolic coupling in the mPFC is critically involved in the stress-induced passive coping response in mice [4].展开更多
Different outcomes of astrocyte inflammatory signalling in injury and neurodegeneration：It is emerging that astrocytes have a significant impact on the neuronal network by modulating synaptic connections and neuronal...Different outcomes of astrocyte inflammatory signalling in injury and neurodegeneration：It is emerging that astrocytes have a significant impact on the neuronal network by modulating synaptic connections and neuronal viability in both normal and pathological states.展开更多
Lactate,a byproduct of glycolysis,was thought to be a metabolic waste until the discovery of the Warburg effect.Lactate not only functions as a metabolic substrate to provide energy but can also function as a signalin...Lactate,a byproduct of glycolysis,was thought to be a metabolic waste until the discovery of the Warburg effect.Lactate not only functions as a metabolic substrate to provide energy but can also function as a signaling molecule to modulate cellular functions under pathophysiological conditions.The Astrocyte-Neuron Lactate Shuttle has cla rified that lactate plays a pivotal role in the central nervous system.Moreover,protein lactylation highlights the novel role of lactate in regulating transcription,cellular functions,and disease development.This review summarizes the recent advances in lactate metabolism and its role in neurodegenerative diseases,thus providing optimal pers pectives for future research.展开更多
Maintaining glutamate homeostasis after hypoxic ischemia is important for synaptic function and neural cell activity,and regulation of glutamate transport between astrocyte and neuron is one of the important modalitie...Maintaining glutamate homeostasis after hypoxic ischemia is important for synaptic function and neural cell activity,and regulation of glutamate transport between astrocyte and neuron is one of the important modalities for reducing glutamate accumulation.However,further research is needed to investigate the dynamic changes in and molecular mechanisms of glutamate transport and the effects of glutamate transport on synapses.The aim of this study was to investigate the regulatory mechanisms underlying Notch pathway mediation of glutamate transport and synaptic plasticity.In this study,Yorkshire neonatal pigs(male,age 3 days,weight 1.0–1.5 kg,n=48)were randomly divided into control(sham surgery group)and five hypoxic ischemia subgroups,according to different recovery time,which were then further subdivided into subgroups treated with dimethyl sulfoxide or a Notch pathway inhibitor(N-[N-(3,5-difluorophenacetyl-l-alanyl)]-S-phenylglycine t-butyl ester).Once the model was established,immunohistochemistry,immunofluorescence staining,and western blot analyses of Notch pathway-related proteins,synaptophysin,and glutamate transporter were performed.Moreover,synapse microstructure was observed by transmission electron microscopy.At the early stage(6–12 hours after hypoxic ischemia)of hypoxic ischemic injury,expression of glutamate transporter excitatory amino acid transporter-2 and synaptophysin was downregulated,the number of synaptic vesicles was reduced,and synaptic swelling was observed;at 12–24 hours after hypoxic ischemia,the Notch pathway was activated,excitatory amino acid transporter-2 and synaptophysin expression was increased,and the number of synaptic vesicles was slightly increased.Excitatory amino acid transporter-2 and synaptophysin expression decreased after treatment with the Notch pathway inhibitor.This suggests that glutamate transport in astrocytes-neurons after hypoxic ischemic injury is regulated by the Notch pathway and affects vesicle release and synaptic plasticity through the expression of sy展开更多
Over the past decade,a growing number of studies have reported transcription factor-based in situ reprogramming that can directly conve rt endogenous glial cells into functional neurons as an alternative approach for ...Over the past decade,a growing number of studies have reported transcription factor-based in situ reprogramming that can directly conve rt endogenous glial cells into functional neurons as an alternative approach for n euro regeneration in the adult mammalian central ne rvous system.Howeve r,many questions remain regarding how a terminally differentiated glial cell can transform into a delicate neuron that forms part of the intricate brain circuitry.In addition,concerns have recently been raised around the absence of astrocyte-to-neuron conversion in astrocytic lineage-tra cing mice.In this study,we employed repetitive two-photon imaging to continuously capture the in situ astrocyte-to-neuron conversion process following ecto pic expression of the neural transcription factor NeuroD1 in both prolife rating reactive astrocytes and lineage-tra ced astrocytes in the mouse cortex.Time-lapse imaging over several wee ks revealed the ste p-by-step transition from a typical astrocyte with numero us short,tapered branches to a typical neuro n with a few long neurites and dynamic growth cones that actively explored the local environment.In addition,these lineage-converting cells were able to migrate ra dially or to ngentially to relocate to suitable positions.Furthermore,two-photon Ca2+imaging and patch-clamp recordings confirmed that the newly generated neuro ns exhibited synchronous calcium signals,repetitive action potentials,and spontaneous synaptic responses,suggesting that they had made functional synaptic connections within local neural circuits.In conclusion,we directly visualized the step-by-step lineage conversion process from astrocytes to functional neurons in vivo and unambiguously demonstrated that adult mammalian brains are highly plastic with respect to their potential for neuro regeneration and neural circuit reconstruction.展开更多
5-Bromo-2′-deoxyuridine(BrdU)is a halogenated pyrimidine that can be incorporated into newly synthesized DNA during the S phase of the cell cycle.BrdU is widely used in fate-mapping studies of embryonic and adult neu...5-Bromo-2′-deoxyuridine(BrdU)is a halogenated pyrimidine that can be incorporated into newly synthesized DNA during the S phase of the cell cycle.BrdU is widely used in fate-mapping studies of embryonic and adult neurogenesis to identify newborn neurons,however side effects on neural stem cells and their progeny have been reported.In vivo astrocyte-to-neuron(AtN)conversion is a new approach for generating newborn neurons by directly converting endogenous astrocytes into neurons.The BrdU-labeling strategy has been used to trace astrocyte-converted neurons,but whether BrdU has any effect on the AtN conversion is unknown.Here,while conducting a NeuroD1-mediated AtN conversion study using BrdU to label dividing reactive astrocytes following ischemic injury,we accidentally discovered that BrdU inhibited AtN conversion.We initially found a gradual reduction in BrdU-labeled astrocytes during NeuroD1-mediated AtN conversion in the mouse cortex.Although most NeuroD1-infected astrocytes were converted into neurons,the number of BrdU-labeled neurons was surprisingly low.To exclude the possibility that this BrdU inhibition was caused by the ischemic injury,we conducted an in vitro AtN conversion study by overexpressing NeuroD1 in cultured cortical astrocytes in the presence or absence of BrdU.Surprisingly,we also found a significantly lower conversion rate and a smaller number of converted neurons in the BrdU-treated group compared with the untreated group.These results revealed an unexpected inhibitory effect of BrdU on AtN conversion,suggesting more caution is needed when using BrdU in AtN conversion studies and in data interpretation.展开更多
基金supported by the National Institute on Alcohol Abuse and Alcoholism(NIAAA)Neurobiology of Adolescent Drinking In Adulthood(NADIA)Grant#2U01AA019925(to HSS)the National Institute on Alcohol Abuse and Alcoholism(NIAAA)R00AA022651(to TAW)the National Institute on Drug Abuse(NIDA)R01DA041455(to KJR)
文摘Adolescent alcohol abuse is a substantive public health problem that has been the subject of intensive study in recent years.Despite reports of a wide range of effects of adolescent intermittent ethanol(AIE)exposure on brain and behavior,little is known about the mechanisms that may underlie those effects,and even less about treatments that might reverse them.Recent studies from our laboratory have indicated that AIE produced enduring changes in astrocyte function and synaptic activity in the hippocampal formation,suggesting the possibility of an alteration in astrocyte-neuronal connectivity and function.We utilized astrocyte-specific,membrane restricted viral labeling paired with immunohistochemistry to perform confocal single cell astrocyte imaging,three-dimensional reconstruction,and quantification of astrocyte morphology in hippocampal area CA1 from adult rats after AIE.Additionally,we assessed the colocalization of astrocyte plasma membrane labeling with immunoreactivity for AMPA-(α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid)glutamate receptor 1,an AMPA receptor subunit and established neuronal marker of excitatory synapses,as a metric of astrocyte-synapse proximity.AIE significantly reduced the colocalization of the astrocyte plasma membrane with synaptic marker puncta in adulthood.This is striking in that it suggests not only an alteration of the physical association of astrocytes with synapses by AIE,but one that lasts into adulthood-well after the termination of alcohol exposure.Perhaps even more notable,the AIE-induced reduction of astrocyte-synapse interaction was reversed by sub-chronic treatment with the clinically used agent,gabapentin(Neurontin),in adulthood.This suggests that a medication in common clinical use may have the potential to reverse some of the enduring effects of adolescent alcohol exposure on brain function.All animal experiments conducted were approved by the Duke University Institutional Animal Care and Use Committee(Protocol Registry Number A159-18-07)on July 27,2018.
文摘Stress is a major risk factor for the development of mental illness,such as major depression disorder (MDD)[1].Despite decades of progress,including findings that stressinduced depression corresponds with numerous morphological and functional neuronal changes within brain structures associated with cognition and mood,such as the medial prefrontal cortex (mPFC)[1-3],a thorough understanding of how stress induces the core symptoms of depression,such as hopelessness,is still lacking.In an exciting new paper in mice,Yin et al.show that astrocyteneuronal metabolic coupling in the mPFC is critically involved in the stress-induced passive coping response in mice [4].
文摘Different outcomes of astrocyte inflammatory signalling in injury and neurodegeneration：It is emerging that astrocytes have a significant impact on the neuronal network by modulating synaptic connections and neuronal viability in both normal and pathological states.
基金supported by the National Natural Science Foundation of China,Nos.82230042 and 81930029(to ZY),U2004201(to FG and RYP)the China Postdoctoral Science Foundation,No.2020M683748(to RYP)。
文摘Lactate,a byproduct of glycolysis,was thought to be a metabolic waste until the discovery of the Warburg effect.Lactate not only functions as a metabolic substrate to provide energy but can also function as a signaling molecule to modulate cellular functions under pathophysiological conditions.The Astrocyte-Neuron Lactate Shuttle has cla rified that lactate plays a pivotal role in the central nervous system.Moreover,protein lactylation highlights the novel role of lactate in regulating transcription,cellular functions,and disease development.This review summarizes the recent advances in lactate metabolism and its role in neurodegenerative diseases,thus providing optimal pers pectives for future research.
基金supported by the National Natural Science Foundation of China,Nos.81871408 and 81271631(to XMW)National Science Foundation for Young Scientists of China,No.81801658(to YZ)+1 种基金Outstanding Scientific Fund of Shengjing Hospital,No.201402(to XMW)345 Talent Support Project of Shengjing Hospital,No.30B(to YZ)。
文摘Maintaining glutamate homeostasis after hypoxic ischemia is important for synaptic function and neural cell activity,and regulation of glutamate transport between astrocyte and neuron is one of the important modalities for reducing glutamate accumulation.However,further research is needed to investigate the dynamic changes in and molecular mechanisms of glutamate transport and the effects of glutamate transport on synapses.The aim of this study was to investigate the regulatory mechanisms underlying Notch pathway mediation of glutamate transport and synaptic plasticity.In this study,Yorkshire neonatal pigs(male,age 3 days,weight 1.0–1.5 kg,n=48)were randomly divided into control(sham surgery group)and five hypoxic ischemia subgroups,according to different recovery time,which were then further subdivided into subgroups treated with dimethyl sulfoxide or a Notch pathway inhibitor(N-[N-(3,5-difluorophenacetyl-l-alanyl)]-S-phenylglycine t-butyl ester).Once the model was established,immunohistochemistry,immunofluorescence staining,and western blot analyses of Notch pathway-related proteins,synaptophysin,and glutamate transporter were performed.Moreover,synapse microstructure was observed by transmission electron microscopy.At the early stage(6–12 hours after hypoxic ischemia)of hypoxic ischemic injury,expression of glutamate transporter excitatory amino acid transporter-2 and synaptophysin was downregulated,the number of synaptic vesicles was reduced,and synaptic swelling was observed;at 12–24 hours after hypoxic ischemia,the Notch pathway was activated,excitatory amino acid transporter-2 and synaptophysin expression was increased,and the number of synaptic vesicles was slightly increased.Excitatory amino acid transporter-2 and synaptophysin expression decreased after treatment with the Notch pathway inhibitor.This suggests that glutamate transport in astrocytes-neurons after hypoxic ischemic injury is regulated by the Notch pathway and affects vesicle release and synaptic plasticity through the expression of sy
基金supported by the National Natural Science Foundation of China,No.31970906(to WLei)the Natural Science Foundation of Guangdong Province,No.2020A1515011079(to WLei)+4 种基金Key Technologies R&D Program of Guangdong Province,No.2018B030332001(to GC)Science and Technology Projects of Guangzhou,No.202206060002(to GC)the Youth Science Program of the National Natural Science Foundation of China,No.32100793(to ZX)the Pearl River Innovation and Entrepreneurship Team,No.2021ZT09 Y552Yi-Liang Liu Endowment Fund from Jinan University Education Development Foundation。
文摘Over the past decade,a growing number of studies have reported transcription factor-based in situ reprogramming that can directly conve rt endogenous glial cells into functional neurons as an alternative approach for n euro regeneration in the adult mammalian central ne rvous system.Howeve r,many questions remain regarding how a terminally differentiated glial cell can transform into a delicate neuron that forms part of the intricate brain circuitry.In addition,concerns have recently been raised around the absence of astrocyte-to-neuron conversion in astrocytic lineage-tra cing mice.In this study,we employed repetitive two-photon imaging to continuously capture the in situ astrocyte-to-neuron conversion process following ecto pic expression of the neural transcription factor NeuroD1 in both prolife rating reactive astrocytes and lineage-tra ced astrocytes in the mouse cortex.Time-lapse imaging over several wee ks revealed the ste p-by-step transition from a typical astrocyte with numero us short,tapered branches to a typical neuro n with a few long neurites and dynamic growth cones that actively explored the local environment.In addition,these lineage-converting cells were able to migrate ra dially or to ngentially to relocate to suitable positions.Furthermore,two-photon Ca2+imaging and patch-clamp recordings confirmed that the newly generated neuro ns exhibited synchronous calcium signals,repetitive action potentials,and spontaneous synaptic responses,suggesting that they had made functional synaptic connections within local neural circuits.In conclusion,we directly visualized the step-by-step lineage conversion process from astrocytes to functional neurons in vivo and unambiguously demonstrated that adult mammalian brains are highly plastic with respect to their potential for neuro regeneration and neural circuit reconstruction.
基金supported by the Natural Science Foundation of Guangdong Province of China,Nos.2021A1515011237(to WL),2020A1515010854(to QSW)the National Natural Science Foundation of China,Nos.U1801681(to GC),31701291(to WL)the Guangdong Province Science and Technology Planning Project of China,No.2018B030332001(to GC)。
文摘5-Bromo-2′-deoxyuridine(BrdU)is a halogenated pyrimidine that can be incorporated into newly synthesized DNA during the S phase of the cell cycle.BrdU is widely used in fate-mapping studies of embryonic and adult neurogenesis to identify newborn neurons,however side effects on neural stem cells and their progeny have been reported.In vivo astrocyte-to-neuron(AtN)conversion is a new approach for generating newborn neurons by directly converting endogenous astrocytes into neurons.The BrdU-labeling strategy has been used to trace astrocyte-converted neurons,but whether BrdU has any effect on the AtN conversion is unknown.Here,while conducting a NeuroD1-mediated AtN conversion study using BrdU to label dividing reactive astrocytes following ischemic injury,we accidentally discovered that BrdU inhibited AtN conversion.We initially found a gradual reduction in BrdU-labeled astrocytes during NeuroD1-mediated AtN conversion in the mouse cortex.Although most NeuroD1-infected astrocytes were converted into neurons,the number of BrdU-labeled neurons was surprisingly low.To exclude the possibility that this BrdU inhibition was caused by the ischemic injury,we conducted an in vitro AtN conversion study by overexpressing NeuroD1 in cultured cortical astrocytes in the presence or absence of BrdU.Surprisingly,we also found a significantly lower conversion rate and a smaller number of converted neurons in the BrdU-treated group compared with the untreated group.These results revealed an unexpected inhibitory effect of BrdU on AtN conversion,suggesting more caution is needed when using BrdU in AtN conversion studies and in data interpretation.
