Direct in vivo conversion of astrocytes into functional new neurons induced by neural transcription factors has been recognized as a potential new therapeutic intervention for neural injury and degenerative disorders....Direct in vivo conversion of astrocytes into functional new neurons induced by neural transcription factors has been recognized as a potential new therapeutic intervention for neural injury and degenerative disorders. However, a few recent studies have claimed that neural transcription factors cannot convert astrocytes into neurons, attributing the converted neurons to pre-existing neurons mis-expressing transgenes. In this study, we overexpressed three distinct neural transcription factors––NeuroD1, Ascl1, and Dlx2––in reactive astrocytes in mouse cortices subjected to stab injury, resulting in a series of significant changes in astrocyte properties. Initially, the three neural transcription factors were exclusively expressed in the nuclei of astrocytes. Over time, however, these astrocytes gradually adopted neuronal morphology, and the neural transcription factors was gradually observed in the nuclei of neuron-like cells instead of astrocytes. Furthermore,we noted that transcription factor-infected astrocytes showed a progressive decrease in the expression of astrocytic markers AQP4(astrocyte endfeet signal), CX43(gap junction signal), and S100β. Importantly, none of these changes could be attributed to transgene leakage into preexisting neurons. Therefore, our findings suggest that neural transcription factors such as NeuroD1, Ascl1, and Dlx2 can effectively convert reactive astrocytes into neurons in the adult mammalian brain.展开更多
The onset of retinal degenerative disease is often associated with neuronal loss. Therefore, how to regenerate new neurons to restore vision is an important issue. NeuroD1 is a neural transcription factor with the abi...The onset of retinal degenerative disease is often associated with neuronal loss. Therefore, how to regenerate new neurons to restore vision is an important issue. NeuroD1 is a neural transcription factor with the ability to reprogram brain astrocytes into neurons in vivo. Here, we demonstrate that in adult mice, NeuroD1 can reprogram Müller cells, the principal glial cell type in the retina, to become retinal neurons. Most strikingly, ectopic expression of NeuroD1 using two different viral vectors converted Müller cells into different cell types. Specifically, AAV7 m8 GFAP681::GFP-ND1 converted Müller cells into inner retinal neurons, including amacrine cells and ganglion cells. In contrast, AAV9 GFAP104::ND1-GFP converted Müller cells into outer retinal neurons such as photoreceptors and horizontal cells, with higher conversion efficiency. Furthermore, we demonstrate that Müller cell conversion induced by AAV9 GFAP104::ND1-GFP displayed clear dose-and time-dependence. These results indicate that Müller cells in adult mice are highly plastic and can be reprogrammed into various subtypes of retinal neurons.展开更多
目的·筛查青少年的成人起病型糖尿病(maturity-onset diabetes of the young,MODY)家系中NEUROD1基因突变,分析突变与中国人MODY6发病的相关性及其潜在的致病机制。方法·采用PCR-直接测序法对96例GCK/MODY2、HNF1A/MODY3、HNF...目的·筛查青少年的成人起病型糖尿病(maturity-onset diabetes of the young,MODY)家系中NEUROD1基因突变,分析突变与中国人MODY6发病的相关性及其潜在的致病机制。方法·采用PCR-直接测序法对96例GCK/MODY2、HNF1A/MODY3、HNF1B/MODY5突变阴性的中国MODY先证者进行NEUROD1突变筛查,同时比较96例MODY先证者与100例非糖尿病对照者NEUROD1基因变异的基因型频率。采用从头建模法构建NEUROD1蛋白野生型和突变体的3D结构,采用双荧光素酶报告基因系统检测野生型和突变体蛋白对胰岛素基因转录活性的影响。结果·在一个MODY家系中发现NEUROD1基因杂合错义突变Glu59Gln (NM_002500.5,c.175G>C)。3D结构分析发现,该突变将野生型中带负电荷的Glu59转化为突变中不带电荷的Gln59,导致两个盐桥键Glu59-Arg54和Glu59-Lys88缺失,并形成一个新的氢键Gln59-Arg54。与野生型相比,Glu59Gln突变体的胰岛素基因转录活性下降36.3%(P<0.05)。与非糖尿病对照相比,96例MODY先证者中Ala45Thr (G-A)变异的AA+GA基因型频率显著升高(P=0.002)。结论·Glu59Gln突变改变了NEUROD1蛋白N端的分子构象,导致其胰岛素基因转录活性显著下降,是该家系突变携带者胰岛素分泌缺陷的原因。Ala45Thr变异与MODY6先证者糖尿病发病年龄的提前有关。展开更多
A new technology called in vivo glia-to-neuron conversion has emerged in recent years as a promising next generation therapy for neural regeneration and repair. This is achieved through reprogramming endogenous glial ...A new technology called in vivo glia-to-neuron conversion has emerged in recent years as a promising next generation therapy for neural regeneration and repair. This is achieved through reprogramming endogenous glial cells into neurons in the central nervous system through ectopically expressing neural transcriptional factors in glial cells. Previous studies have been focusing on glial cells in the grey matter such as the cortex and striatum, but whether glial cells in the white matter can be reprogrammed or not is unknown. To address this fundamental question, we express NeuroD1 in the astrocytes of both grey matter(cortex and striatum) and white matter(corpus callosum) to investigate the conversion efficiency, neuronal subtypes, and electrophysiological features of the converted neurons. We discover that NeuroD1 can efficiently reprogram the astrocytes in the grey matter into functional neurons, but the astrocytes in the white matter are much resistant to neuronal reprogramming. The converted neurons from cortical and striatal astrocytes are composed of both glutamatergic and GABAergic neurons, capable of firing action potentials and having spontaneous synaptic activities. In contrast, the few astrocyte-converted neurons in the white matter are rather immature with rare synaptic events. These results provide novel insights into the differential reprogramming capability between the astrocytes in the grey matter versus the white matter, and highlight the impact of regional astrocytes as well as microenvironment on the outcome of glia-toneuron conversion. Since human brain has large volume of white matter, this study will provide important guidance for future development of in vivo glia-to-neuron conversion technology into potential clinical therapies. Experimental protocols in this study were approved by the Laboratory Animal Ethics Committee of Jinan University(approval No. IACUC-20180321-03) on March 21, 2018.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
Objective::In contrast to the most commonly reported forms of maturity-onset diabetes of the young(MODY),including MODY2,MODY3 and MODY5,MODY6 is a relatively rare subtype.To investigate whether NEUROD1 is responsible...Objective::In contrast to the most commonly reported forms of maturity-onset diabetes of the young(MODY),including MODY2,MODY3 and MODY5,MODY6 is a relatively rare subtype.To investigate whether NEUROD1 is responsible for MODY in Chinese individuals,we screened its mutations in MODY pedigrees and explored the potential pathogenic mechanisms.Methods::Polymerase chain reaction direct sequencing was performed to screen NEUROD1 mutations in 32 Chinese MODY probands who were negative for the GCK/MODY2,HNF1A/MODY3 and HNF1B/MODY5 genes in this observational study.In addition,we enrolled 201 unrelated,non-diabetic control subjects of Han Chinese descent.The functional significance of newly identified mutations was analyzed using clinical phenotype,pathophysiology and three-dimensional structure studies.This study was approved by the Institutional Review Board of Shanghai Jiao Tong University Affiliated Sixth People’s Hospital,China(approval No.YS-2017-83)on March 3,2017.Results::E59Q(c.175 G>C,p.Glu59Gln),a heterozygous missense mutation in the NEUROD1 gene,was identified in one family with MODY.The Glu59 residue in NeuroD1 is highly conserved across mammalian species.Four diabetic patients carrying the mutation(a proband and her son,brother and sister)were lean,with a body mass index of 20.9(20.3-21.2)kg/m 2.Compared with their unaffected relatives(n=4),E59Q carriers(n=4)had significantly decreased ratios of fasting and 2-hour insulin to plasma glucose(both fasting plasma insulin/fasting plasma glucose and 2-hour postprandial plasma insulin/2-hour postprandial plasma glucose,P<0.005).The proband’s father had an E59Q mutation and normal glucose tolerance,which suggested non-penetrance.The E59Q mutation was not detected in other probands or in the 201 control subjects with normal glucose tolerance.Two salt-bridge bonds of Glu59 were disrupted at the Q59 mutation site.Conclusion::The NEUROD1-E59Q mutation changed the molecular conformation of the N-terminal in NeuroD1,which may decrease binding of the E59Q mutant to the insulin promoter and insulin gene transcription activity,therefore causing the MODY6 subtype with defective insulin secretion.展开更多
1文献来源研究一:Rudin CM,Poirier JT,Byers LA,et al.Molecular subtypes of small cell lung cancer:A synthesis of human and mouse model data[J].Nat Rev Cancer,2019,19(5):289-297.研究二:Owonikoko TK,Dwivedi B,Chen ZJ,et a...1文献来源研究一:Rudin CM,Poirier JT,Byers LA,et al.Molecular subtypes of small cell lung cancer:A synthesis of human and mouse model data[J].Nat Rev Cancer,2019,19(5):289-297.研究二:Owonikoko TK,Dwivedi B,Chen ZJ,et al.YAP1 positive small-cell lung cancer subtype is associated with the T-cell inflamed gene expression profile and confers good prognosis and long term survival[J].J Clin Oncol,2020,38(15S):Abstr 9019.展开更多
Spinal cord injury represents a devastating central nervous system injury that could impair the mobility and sensory function of afflicted patients.The hallmarks of spinal cord injury include neuroinflammation,axonal ...Spinal cord injury represents a devastating central nervous system injury that could impair the mobility and sensory function of afflicted patients.The hallmarks of spinal cord injury include neuroinflammation,axonal degeneration,neuronal loss,and reactive gliosis.Furthermore,the formation of a glial scar at the injury site elicits an inhibitory environment for potential neuroregeneration.Besides axonal regeneration,a significant challenge in treating spinal cord injury is to replenish the neurons lost during the pathological process.However,despite decades of research efforts,current strategies including stem cell transplantation have not resulted in a successful clinical therapy.Furthermore,stem cell transplantation faces serious hurdles such as immunorejection of the transplanted cells and ethical issues.In vivo neuronal reprogramming is a recently developed technology and leading a major breakthrough in regenerative medicine.This innovative technology converts endogenous glial cells into functional neurons for injury repair in the central nervous system.The feasibility of in vivo neuronal reprogramming has been demonstrated successfully in models of different neurological disorders including spinal cord injury by numerous laboratories.Several reprogramming factors,mainly the pro-neural transcription factors,have been utilized to reprogram endogenous glial cells into functional neurons with distinct phenotypes.So far,the literature on in vivo neuronal reprogramming in the model of spinal cord injury is still small.In this review,we summarize a limited number of such reports and discuss several questions that we think are important for applying in vivo neuronal reprogramming in the research field of spinal cord injury as well as other central nervous system disorders.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
青少年发病的成人糖尿病（maturity-onset diabetes of the young, MODY）以常染色体显性遗传为特征，是最常见的单基因糖尿病类型，多在25岁以前发病，无胰腺自身免疫（典型1型糖尿病）和胰岛素抵抗（典型2型糖尿病）。迄今为止，已发...青少年发病的成人糖尿病（maturity-onset diabetes of the young, MODY）以常染色体显性遗传为特征，是最常见的单基因糖尿病类型，多在25岁以前发病，无胰腺自身免疫（典型1型糖尿病）和胰岛素抵抗（典型2型糖尿病）。迄今为止，已发现14个基因（HNF4α、GCK、HNF1α、IPF1、NNF1β、NEUROD1、KLF11、CEL、PAX4、INS、BLK、ABCC8、KCNJ11、APPL1）与之相关。据统计，MODY患者占欧美国家糖尿病患者的2%～5%，不典型的临床特征导致该病诊断较为困难。明确MODY诊断对指导进一步治疗、判断患者预后和遗传咨询有重要意义。我国MODY流行病学研究处于起步阶段，基因分布情况尚不明确。现报道1例MODY11新突变位点病例。展开更多
基金supported by the Key Project of Guangzhou City,No.202206060002Science and Technology Project of Guangdong Province,No.2018B030332001Guangdong Provincial Pearl River Project,No.2021ZT09Y552 (all to GC)。
文摘Direct in vivo conversion of astrocytes into functional new neurons induced by neural transcription factors has been recognized as a potential new therapeutic intervention for neural injury and degenerative disorders. However, a few recent studies have claimed that neural transcription factors cannot convert astrocytes into neurons, attributing the converted neurons to pre-existing neurons mis-expressing transgenes. In this study, we overexpressed three distinct neural transcription factors––NeuroD1, Ascl1, and Dlx2––in reactive astrocytes in mouse cortices subjected to stab injury, resulting in a series of significant changes in astrocyte properties. Initially, the three neural transcription factors were exclusively expressed in the nuclei of astrocytes. Over time, however, these astrocytes gradually adopted neuronal morphology, and the neural transcription factors was gradually observed in the nuclei of neuron-like cells instead of astrocytes. Furthermore,we noted that transcription factor-infected astrocytes showed a progressive decrease in the expression of astrocytic markers AQP4(astrocyte endfeet signal), CX43(gap junction signal), and S100β. Importantly, none of these changes could be attributed to transgene leakage into preexisting neurons. Therefore, our findings suggest that neural transcription factors such as NeuroD1, Ascl1, and Dlx2 can effectively convert reactive astrocytes into neurons in the adult mammalian brain.
基金supported by the Guangdong Grant Key Technologies for Treatment of Brain Disorders,China,No. 2018B030332001 (to GC)the Guangzhou Key Projects of Brain Science and Brain-Like Intelligence Technology,No. 20200730009 (to YX)the Guangdong Basic and Applied Basic Research Foundation,No. 2020A1515110898 (to WYC)。
文摘The onset of retinal degenerative disease is often associated with neuronal loss. Therefore, how to regenerate new neurons to restore vision is an important issue. NeuroD1 is a neural transcription factor with the ability to reprogram brain astrocytes into neurons in vivo. Here, we demonstrate that in adult mice, NeuroD1 can reprogram Müller cells, the principal glial cell type in the retina, to become retinal neurons. Most strikingly, ectopic expression of NeuroD1 using two different viral vectors converted Müller cells into different cell types. Specifically, AAV7 m8 GFAP681::GFP-ND1 converted Müller cells into inner retinal neurons, including amacrine cells and ganglion cells. In contrast, AAV9 GFAP104::ND1-GFP converted Müller cells into outer retinal neurons such as photoreceptors and horizontal cells, with higher conversion efficiency. Furthermore, we demonstrate that Müller cell conversion induced by AAV9 GFAP104::ND1-GFP displayed clear dose-and time-dependence. These results indicate that Müller cells in adult mice are highly plastic and can be reprogrammed into various subtypes of retinal neurons.
文摘目的·筛查青少年的成人起病型糖尿病(maturity-onset diabetes of the young,MODY)家系中NEUROD1基因突变,分析突变与中国人MODY6发病的相关性及其潜在的致病机制。方法·采用PCR-直接测序法对96例GCK/MODY2、HNF1A/MODY3、HNF1B/MODY5突变阴性的中国MODY先证者进行NEUROD1突变筛查,同时比较96例MODY先证者与100例非糖尿病对照者NEUROD1基因变异的基因型频率。采用从头建模法构建NEUROD1蛋白野生型和突变体的3D结构,采用双荧光素酶报告基因系统检测野生型和突变体蛋白对胰岛素基因转录活性的影响。结果·在一个MODY家系中发现NEUROD1基因杂合错义突变Glu59Gln (NM_002500.5,c.175G>C)。3D结构分析发现,该突变将野生型中带负电荷的Glu59转化为突变中不带电荷的Gln59,导致两个盐桥键Glu59-Arg54和Glu59-Lys88缺失,并形成一个新的氢键Gln59-Arg54。与野生型相比,Glu59Gln突变体的胰岛素基因转录活性下降36.3%(P<0.05)。与非糖尿病对照相比,96例MODY先证者中Ala45Thr (G-A)变异的AA+GA基因型频率显著升高(P=0.002)。结论·Glu59Gln突变改变了NEUROD1蛋白N端的分子构象,导致其胰岛素基因转录活性显著下降,是该家系突变携带者胰岛素分泌缺陷的原因。Ala45Thr变异与MODY6先证者糖尿病发病年龄的提前有关。
基金supported in part by the National Natural Science Foundation of China(Grant No.31701291 to WL,U1801681 to GC)the China Postdoctoral Science Foundation(Grant No.2016M602600 to WL)+1 种基金the Guangdong Grant ‘Key Technologies for Treatment of Brain Disorders’(Grant No.2018B030332001 to GC)the Internal Funding of Jinan University,China(Grant No.21616110 to GC)
文摘A new technology called in vivo glia-to-neuron conversion has emerged in recent years as a promising next generation therapy for neural regeneration and repair. This is achieved through reprogramming endogenous glial cells into neurons in the central nervous system through ectopically expressing neural transcriptional factors in glial cells. Previous studies have been focusing on glial cells in the grey matter such as the cortex and striatum, but whether glial cells in the white matter can be reprogrammed or not is unknown. To address this fundamental question, we express NeuroD1 in the astrocytes of both grey matter(cortex and striatum) and white matter(corpus callosum) to investigate the conversion efficiency, neuronal subtypes, and electrophysiological features of the converted neurons. We discover that NeuroD1 can efficiently reprogram the astrocytes in the grey matter into functional neurons, but the astrocytes in the white matter are much resistant to neuronal reprogramming. The converted neurons from cortical and striatal astrocytes are composed of both glutamatergic and GABAergic neurons, capable of firing action potentials and having spontaneous synaptic activities. In contrast, the few astrocyte-converted neurons in the white matter are rather immature with rare synaptic events. These results provide novel insights into the differential reprogramming capability between the astrocytes in the grey matter versus the white matter, and highlight the impact of regional astrocytes as well as microenvironment on the outcome of glia-toneuron conversion. Since human brain has large volume of white matter, this study will provide important guidance for future development of in vivo glia-to-neuron conversion technology into potential clinical therapies. Experimental protocols in this study were approved by the Laboratory Animal Ethics Committee of Jinan University(approval No. IACUC-20180321-03) on March 21, 2018.
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 National Natural Science Foundation of China(Nos.81970686,81770791,81471012,81270876,to LL)the Interdisciplinary Program of Shanghai Jiao Tong University,China(No.YG2019ZDA08,to LL)+1 种基金the Shanghai Leading Talent,China(No.SLJ15055,to LL)the National Institute of Diabetes and Digestive and Kidney Diseases(No.SC1DK104821,to YL)
文摘Objective::In contrast to the most commonly reported forms of maturity-onset diabetes of the young(MODY),including MODY2,MODY3 and MODY5,MODY6 is a relatively rare subtype.To investigate whether NEUROD1 is responsible for MODY in Chinese individuals,we screened its mutations in MODY pedigrees and explored the potential pathogenic mechanisms.Methods::Polymerase chain reaction direct sequencing was performed to screen NEUROD1 mutations in 32 Chinese MODY probands who were negative for the GCK/MODY2,HNF1A/MODY3 and HNF1B/MODY5 genes in this observational study.In addition,we enrolled 201 unrelated,non-diabetic control subjects of Han Chinese descent.The functional significance of newly identified mutations was analyzed using clinical phenotype,pathophysiology and three-dimensional structure studies.This study was approved by the Institutional Review Board of Shanghai Jiao Tong University Affiliated Sixth People’s Hospital,China(approval No.YS-2017-83)on March 3,2017.Results::E59Q(c.175 G>C,p.Glu59Gln),a heterozygous missense mutation in the NEUROD1 gene,was identified in one family with MODY.The Glu59 residue in NeuroD1 is highly conserved across mammalian species.Four diabetic patients carrying the mutation(a proband and her son,brother and sister)were lean,with a body mass index of 20.9(20.3-21.2)kg/m 2.Compared with their unaffected relatives(n=4),E59Q carriers(n=4)had significantly decreased ratios of fasting and 2-hour insulin to plasma glucose(both fasting plasma insulin/fasting plasma glucose and 2-hour postprandial plasma insulin/2-hour postprandial plasma glucose,P<0.005).The proband’s father had an E59Q mutation and normal glucose tolerance,which suggested non-penetrance.The E59Q mutation was not detected in other probands or in the 201 control subjects with normal glucose tolerance.Two salt-bridge bonds of Glu59 were disrupted at the Q59 mutation site.Conclusion::The NEUROD1-E59Q mutation changed the molecular conformation of the N-terminal in NeuroD1,which may decrease binding of the E59Q mutant to the insulin promoter and insulin gene transcription activity,therefore causing the MODY6 subtype with defective insulin secretion.
文摘1文献来源研究一:Rudin CM,Poirier JT,Byers LA,et al.Molecular subtypes of small cell lung cancer:A synthesis of human and mouse model data[J].Nat Rev Cancer,2019,19(5):289-297.研究二:Owonikoko TK,Dwivedi B,Chen ZJ,et al.YAP1 positive small-cell lung cancer subtype is associated with the T-cell inflamed gene expression profile and confers good prognosis and long term survival[J].J Clin Oncol,2020,38(15S):Abstr 9019.
基金supported by startup funds from Medical College of Georgia at Augusta University(to HL)National Institutes of Health R01NS117918,R21NS104394,and R21NS119732(to HL)。
文摘Spinal cord injury represents a devastating central nervous system injury that could impair the mobility and sensory function of afflicted patients.The hallmarks of spinal cord injury include neuroinflammation,axonal degeneration,neuronal loss,and reactive gliosis.Furthermore,the formation of a glial scar at the injury site elicits an inhibitory environment for potential neuroregeneration.Besides axonal regeneration,a significant challenge in treating spinal cord injury is to replenish the neurons lost during the pathological process.However,despite decades of research efforts,current strategies including stem cell transplantation have not resulted in a successful clinical therapy.Furthermore,stem cell transplantation faces serious hurdles such as immunorejection of the transplanted cells and ethical issues.In vivo neuronal reprogramming is a recently developed technology and leading a major breakthrough in regenerative medicine.This innovative technology converts endogenous glial cells into functional neurons for injury repair in the central nervous system.The feasibility of in vivo neuronal reprogramming has been demonstrated successfully in models of different neurological disorders including spinal cord injury by numerous laboratories.Several reprogramming factors,mainly the pro-neural transcription factors,have been utilized to reprogram endogenous glial cells into functional neurons with distinct phenotypes.So far,the literature on in vivo neuronal reprogramming in the model of spinal cord injury is still small.In this review,we summarize a limited number of such reports and discuss several questions that we think are important for applying in vivo neuronal reprogramming in the research field of spinal cord injury as well as other central nervous system disorders.
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.
文摘青少年发病的成人糖尿病（maturity-onset diabetes of the young, MODY）以常染色体显性遗传为特征，是最常见的单基因糖尿病类型，多在25岁以前发病，无胰腺自身免疫（典型1型糖尿病）和胰岛素抵抗（典型2型糖尿病）。迄今为止，已发现14个基因（HNF4α、GCK、HNF1α、IPF1、NNF1β、NEUROD1、KLF11、CEL、PAX4、INS、BLK、ABCC8、KCNJ11、APPL1）与之相关。据统计，MODY患者占欧美国家糖尿病患者的2%～5%，不典型的临床特征导致该病诊断较为困难。明确MODY诊断对指导进一步治疗、判断患者预后和遗传咨询有重要意义。我国MODY流行病学研究处于起步阶段，基因分布情况尚不明确。现报道1例MODY11新突变位点病例。
