Autophagy has been suggested to participate in the pathology of hypoxic-ischemic brain damage（HIBD）.However,its regulatory role in HIBD remains unclear and was thus examined here using a rat model.To induce HIBD,the...Autophagy has been suggested to participate in the pathology of hypoxic-ischemic brain damage（HIBD）.However,its regulatory role in HIBD remains unclear and was thus examined here using a rat model.To induce HIBD,the left common carotid artery was ligated in neonatal rats,and the rats were subjected to hypoxia for 2 hours.Some of these rats were intraperitoneally pretreated with the autophagy inhibitor 3-methyladenine（10 m M in 10 μL） or the autophagy stimulator rapamycin（1 g/kg） 1 hour before artery ligation.Our findings demonstrated that hypoxia-ischemia-induced hippocampal injury in neonatal rats was accompanied by increased expression levels of the autophagy-related proteins light chain 3 and Beclin-1 as well as of the AMPA receptor subunit GluR 1,but by reduced expression of GluR 2.Pretreatment with the autophagy inhibitor 3-methyladenine blocked hypoxia-ischemia-induced hippocampal injury,whereas pretreatment with the autophagy stimulator rapamycin significantly augmented hippocampal injury.Additionally,3-methyladenine pretreatment blocked the hypoxia-ischemia-induced upregulation of Glu R1 and downregulation of GluR2 in the hippocampus.By contrast,rapamycin further elevated hippocampal Glu R1 levels and exacerbated decreased GluR2 expression levels in neonates with HIBD.Our results indicate that autophagy inhibition favors the prevention of HIBD in neonatal rats,at least in part,through normalizing Glu R1 and GluR2 expression.展开更多
Our previous studies have demonstrated that TP53-induced glycolysis and apoptosis regulator(TIGAR)can protect neurons after cerebral ischemia/reperfusion.However,the role of TIGAR in neonatal hypoxic-ischemic brain da...Our previous studies have demonstrated that TP53-induced glycolysis and apoptosis regulator(TIGAR)can protect neurons after cerebral ischemia/reperfusion.However,the role of TIGAR in neonatal hypoxic-ischemic brain damage(HIBD)remains unknown.In the present study,7-day-old Sprague-Dawley rat models of HIBD were established by permanent occlusion of the left common carotid artery followed by 2-hour hypoxia.At 6 days before induction of HIBD,a lentiviral vector containing short hairpin RNA of either TIGAR or gasdermin D(LV-sh_TIGAR or LV-sh_GSDMD)was injected into the left lateral ventricle and striatum.Highly aggressively proliferating immortalized(HAPI)microglial cell models of in vitro HIBD were established by 2-hour oxygen/glucose deprivation followed by 24-hour reoxygenation.Three days before in vitro HIBD induction,HAPI microglial cells were transfected with LV-sh_TIGAR or LV-sh_GSDMD.Our results showed that TIGAR expression was increased in the neonatal rat cortex after HIBD and in HAPI microglial cells after oxygen/glucose deprivation/reoxygenation.Lentivirusmediated TIGAR knockdown in rats markedly worsened pyroptosis and brain damage after hypoxia/ischemia in vivo and in vitro.Application of exogenous nicotinamide adenine dinucleotide phosphate(NADPH)increased the NADPH level and the glutathione/oxidized glutathione ratio and decreased reactive oxygen species levels in HAPI microglial cells after oxygen/glucose deprivation/reoxygenation.Additionally,exogenous NADPH blocked the effects of TIGAR knockdown in neonatal HIBD in vivo and in vitro.These findings show that TIGAR can inhibit microglial pyroptosis and play a protective role in neonatal HIBD.The study was approved by the Animal Ethics Committee of Soochow University of China(approval No.2017LW003)in 2017.展开更多
Transient receptor potential melastatin 2(TRPM2) is an important ion channel that represents a potential target for treating injury caused by cerebral ischemia. However, it is unclear whether reducing TRPM2 expression...Transient receptor potential melastatin 2(TRPM2) is an important ion channel that represents a potential target for treating injury caused by cerebral ischemia. However, it is unclear whether reducing TRPM2 expression can help repair cerebral injury, and if so what the mechanism underlying this process involves. This study investigated the protective effect of reducing TRPM2 expression on pheochromocytoma(PC12) cells injured by oxygen-glucose deprivation(OGD). PC12 cells were transfected with plasmid encoding TRPM2 shRNAS, then subjected to OGD by incubation in glucose-free medium under hypoxic conditions for 8 hours, after which the cells were allowed to reoxygenate for 24 hours. Apoptotic cells, mitochondrial membrane potentials, reactive oxygen species levels, and cellular calcium levels were detected using flow cytometry. The relative expression of C-X-C motif chemokine ligand 2(CXCL2), NACHT, LRR, and PYD domain–containing protein 3(NALP3), and caspase-1 were detected using fluorescence-based quantitative reverse transcription-polymerase chain reaction and western blotting. The rates of apoptosis, mitochondrial membrane potentials, reactive oxygen species levels, and cellular calcium levels in the TRPM2-shRNA + OGD group were lower than those observed in the OGD group. Taken together, these results suggest that TRPM2 knockdown reduces OGD-induced neuronal injury, potentially by inhibiting apoptosis and reducing oxidative stress levels, mitochondrial membrane potentials, intracellular calcium concentrations, and NLRP3 inflammasome activation.展开更多
Circadian rhythm disorder is a common,but often neglected,consequence of neonatal hypoxic-ischemic brain damage(HIBD).However,the underlying molecular mechanisms remain largely unknown.We previously showed that,in a r...Circadian rhythm disorder is a common,but often neglected,consequence of neonatal hypoxic-ischemic brain damage(HIBD).However,the underlying molecular mechanisms remain largely unknown.We previously showed that,in a rat model of HIBD,up-regulation of microRNA-325(miR-325)in the pineal gland is responsible for the suppression of Aanat,a key enzyme involved in melatonin synthesis and circadian rhythm regulation.To better understand the mechanism by which miR-325 affects circadian rhythms in neonates with HIBD,we compared clinical samples from neonates with HIBD and samples from healthy neonates recruited from the First Affiliated Hospital of Soochow University(Dushuhu Branch)in 2019.We found that circulating miR-325 levels correlated positively with the severity of sleep and circadian rhythm disorders in neonates with HIBD.Furthermore,a luciferase reporter gene assay revealed that LIM homeobox 3(LHX3)is a novel downstream target of miR-325.In addition,in miR-325 knock-down mice,the transcription factor LHX3 exhibited an miR-325-dependent circadian pattern of expression in the pineal gland.We established a neonatal mouse model of HIBD by performing doublelayer ligation of the left common carotid artery and exposing the pups to a low-oxygen environment for 2 hours.Lhx3 mRNA expression was significantly down-regulated in these mice and partially rescued in miR-325 knockout mice subjected to the same conditions.Finally,we showed that improvement in circadian rhythm-related behaviors in animals with HIBD was dependent on both miR-325 and LHX3.Taken together,our findings suggest that the miR-325-LHX3 axis is responsible for regulating circadian rhythms and provide novel insights into the identification of potential therapeutic targets for circadian rhythm disorders in patients with neonatal HIBD.The clinical trial was approved by Institutional Review Board of Children’s Hospital of Soochow University(approval No.2015028)on July 20,2015.Animal experiments were approved by Animal Care and Use Committee,School of Medicine,Soochow University,China(approval No.XD-2016-1)on January 15,2016.展开更多
基金supported by the National Natural Science Foundation of China,No.81471488,81271378,81502157,and 81501291the Key Medical Subjects of Jiangsu Province of China,No.XK201120+3 种基金the Jiangsu Province Key Research and Development of Special Funds in China,No.BE2015644the Science and Technology Project of Suzhou City of China,No.SYSD2013105,SYS201446,SYS201441the Public Health Technology Project of Suzhou City of China,No.SS201536the Department of Pediatrics Clinical Center of Suzhou City of China,No.Szzx201504
文摘Autophagy has been suggested to participate in the pathology of hypoxic-ischemic brain damage（HIBD）.However,its regulatory role in HIBD remains unclear and was thus examined here using a rat model.To induce HIBD,the left common carotid artery was ligated in neonatal rats,and the rats were subjected to hypoxia for 2 hours.Some of these rats were intraperitoneally pretreated with the autophagy inhibitor 3-methyladenine（10 m M in 10 μL） or the autophagy stimulator rapamycin（1 g/kg） 1 hour before artery ligation.Our findings demonstrated that hypoxia-ischemia-induced hippocampal injury in neonatal rats was accompanied by increased expression levels of the autophagy-related proteins light chain 3 and Beclin-1 as well as of the AMPA receptor subunit GluR 1,but by reduced expression of GluR 2.Pretreatment with the autophagy inhibitor 3-methyladenine blocked hypoxia-ischemia-induced hippocampal injury,whereas pretreatment with the autophagy stimulator rapamycin significantly augmented hippocampal injury.Additionally,3-methyladenine pretreatment blocked the hypoxia-ischemia-induced upregulation of Glu R1 and downregulation of GluR2 in the hippocampus.By contrast,rapamycin further elevated hippocampal Glu R1 levels and exacerbated decreased GluR2 expression levels in neonates with HIBD.Our results indicate that autophagy inhibition favors the prevention of HIBD in neonatal rats,at least in part,through normalizing Glu R1 and GluR2 expression.
基金supported by the National Natural Science Foundation of China,Nos.81872845(to ML),81771625(to XF)the Natural Science Foundation of Jiangsu Province of China,No.BK20180207(to ML)+4 种基金Jiangsu Provincial Medical Youth Talent of China,No.QNRC2016762(to ML)the Pediatric Clinical Center of Suzhou City of China,No.Szzx201504(to XF)Postgraduate Research&Practice Innovation Program of Jiangsu Province of China,No.KYCX19_1998(to LLT)Jiangsu Government Scholarship for Overseas Studies of China,No.JS-2017-127(to ML)the Fifth Batch of Gusu Health Talent Plan of China(to ML).
文摘Our previous studies have demonstrated that TP53-induced glycolysis and apoptosis regulator(TIGAR)can protect neurons after cerebral ischemia/reperfusion.However,the role of TIGAR in neonatal hypoxic-ischemic brain damage(HIBD)remains unknown.In the present study,7-day-old Sprague-Dawley rat models of HIBD were established by permanent occlusion of the left common carotid artery followed by 2-hour hypoxia.At 6 days before induction of HIBD,a lentiviral vector containing short hairpin RNA of either TIGAR or gasdermin D(LV-sh_TIGAR or LV-sh_GSDMD)was injected into the left lateral ventricle and striatum.Highly aggressively proliferating immortalized(HAPI)microglial cell models of in vitro HIBD were established by 2-hour oxygen/glucose deprivation followed by 24-hour reoxygenation.Three days before in vitro HIBD induction,HAPI microglial cells were transfected with LV-sh_TIGAR or LV-sh_GSDMD.Our results showed that TIGAR expression was increased in the neonatal rat cortex after HIBD and in HAPI microglial cells after oxygen/glucose deprivation/reoxygenation.Lentivirusmediated TIGAR knockdown in rats markedly worsened pyroptosis and brain damage after hypoxia/ischemia in vivo and in vitro.Application of exogenous nicotinamide adenine dinucleotide phosphate(NADPH)increased the NADPH level and the glutathione/oxidized glutathione ratio and decreased reactive oxygen species levels in HAPI microglial cells after oxygen/glucose deprivation/reoxygenation.Additionally,exogenous NADPH blocked the effects of TIGAR knockdown in neonatal HIBD in vivo and in vitro.These findings show that TIGAR can inhibit microglial pyroptosis and play a protective role in neonatal HIBD.The study was approved by the Animal Ethics Committee of Soochow University of China(approval No.2017LW003)in 2017.
基金supported by the National Natural Science Foundation of China,Nos.81671532,81771625(to XF)the Jiangsu Provincial Key Medical Discipline of China,No.ZDXKA2016013(to XF)+3 种基金the Jiangsu Provincial Medical Youth Talent of China,No.QNRC2016758(to XF)the Jiangsu Province Women and Children Health Research Project of China,No.F201750(to XF)the Public Health Technology Project of Suzhou City of China,No.SYS201765(to XF)a grant from the Department of Pediatrics Clinical Center of Suzhou City of China,No.Szzx201504(to XF)。
文摘Transient receptor potential melastatin 2(TRPM2) is an important ion channel that represents a potential target for treating injury caused by cerebral ischemia. However, it is unclear whether reducing TRPM2 expression can help repair cerebral injury, and if so what the mechanism underlying this process involves. This study investigated the protective effect of reducing TRPM2 expression on pheochromocytoma(PC12) cells injured by oxygen-glucose deprivation(OGD). PC12 cells were transfected with plasmid encoding TRPM2 shRNAS, then subjected to OGD by incubation in glucose-free medium under hypoxic conditions for 8 hours, after which the cells were allowed to reoxygenate for 24 hours. Apoptotic cells, mitochondrial membrane potentials, reactive oxygen species levels, and cellular calcium levels were detected using flow cytometry. The relative expression of C-X-C motif chemokine ligand 2(CXCL2), NACHT, LRR, and PYD domain–containing protein 3(NALP3), and caspase-1 were detected using fluorescence-based quantitative reverse transcription-polymerase chain reaction and western blotting. The rates of apoptosis, mitochondrial membrane potentials, reactive oxygen species levels, and cellular calcium levels in the TRPM2-shRNA + OGD group were lower than those observed in the OGD group. Taken together, these results suggest that TRPM2 knockdown reduces OGD-induced neuronal injury, potentially by inhibiting apoptosis and reducing oxidative stress levels, mitochondrial membrane potentials, intracellular calcium concentrations, and NLRP3 inflammasome activation.
基金This study was supported by the National Natural Science Foundation of China,Nos.81871193(to XD),81671532(to BS),81771625&81701490(to XF),81801505(to MG)Jiangsu Provincial Medical Youth Talent of China,Nos.QNRC2016763(to XD),QNRC2016758(to LXX),QNRC2016762(to ML)+7 种基金the Science and Technology Project of Suzhou City of China,No.SS201709(to XD)the Natural Science Foundation of Jiangsu Province of China,No.BK20180205(to XD)the Training Program Foundation for Health Talents of Gusu of China,No.GSWS2019049(to XD)the Jiangsu Provincial Key Medical Discipline of China,No.ZDXKA2016013(to XF)the Jiangsu Province Women and Children Health Research Project of China,No.F201750(to LXX)the Pediatric Clinical Center of Suzhou City of China,No.Szzx201504(to XF)Suzhou Industrial Technology Innovation Project of China,No.SYS201765(to LZ)the Project of Suzhou Science,Education and Health and Technology,China,No.KJXW2018018(to ML).
文摘Circadian rhythm disorder is a common,but often neglected,consequence of neonatal hypoxic-ischemic brain damage(HIBD).However,the underlying molecular mechanisms remain largely unknown.We previously showed that,in a rat model of HIBD,up-regulation of microRNA-325(miR-325)in the pineal gland is responsible for the suppression of Aanat,a key enzyme involved in melatonin synthesis and circadian rhythm regulation.To better understand the mechanism by which miR-325 affects circadian rhythms in neonates with HIBD,we compared clinical samples from neonates with HIBD and samples from healthy neonates recruited from the First Affiliated Hospital of Soochow University(Dushuhu Branch)in 2019.We found that circulating miR-325 levels correlated positively with the severity of sleep and circadian rhythm disorders in neonates with HIBD.Furthermore,a luciferase reporter gene assay revealed that LIM homeobox 3(LHX3)is a novel downstream target of miR-325.In addition,in miR-325 knock-down mice,the transcription factor LHX3 exhibited an miR-325-dependent circadian pattern of expression in the pineal gland.We established a neonatal mouse model of HIBD by performing doublelayer ligation of the left common carotid artery and exposing the pups to a low-oxygen environment for 2 hours.Lhx3 mRNA expression was significantly down-regulated in these mice and partially rescued in miR-325 knockout mice subjected to the same conditions.Finally,we showed that improvement in circadian rhythm-related behaviors in animals with HIBD was dependent on both miR-325 and LHX3.Taken together,our findings suggest that the miR-325-LHX3 axis is responsible for regulating circadian rhythms and provide novel insights into the identification of potential therapeutic targets for circadian rhythm disorders in patients with neonatal HIBD.The clinical trial was approved by Institutional Review Board of Children’s Hospital of Soochow University(approval No.2015028)on July 20,2015.Animal experiments were approved by Animal Care and Use Committee,School of Medicine,Soochow University,China(approval No.XD-2016-1)on January 15,2016.
