目的检测柯萨奇B3病毒(coxsackievirus group B type3,CVB3)感染体外培养的星形胶质细胞后集聚蛋白(agrin)的表达变化及其意义。方法采用免疫细胞化学的方法鉴定培养的星形胶质细胞,在显微镜下观察CVB3感染后的细胞形态,并用RT-PCR方法...目的检测柯萨奇B3病毒(coxsackievirus group B type3,CVB3)感染体外培养的星形胶质细胞后集聚蛋白(agrin)的表达变化及其意义。方法采用免疫细胞化学的方法鉴定培养的星形胶质细胞,在显微镜下观察CVB3感染后的细胞形态,并用RT-PCR方法扩增CVB3RNA的正负链以确证感染成功,用RT-PCR检测CVB3感染细胞后agrin的动态表达变化。用脂质体将agrin反义质粒pcDNA3-As-AG转染到星形胶质细胞,并用RT-PCR检测转染的细胞中agrin的表达。3H-TdR掺入法测定CVB3不同感染时间点的星形胶质细胞裂解液和经agrin反义质粒pcDNA-As-AG转染细胞后的细胞裂解液对T细胞增殖的影响。结果(1)CVB3感染星形胶质细胞后agrin的表达水平下调。(2)病毒感染后随着agrin表达量的降低,星形胶质细胞裂解液对T细胞的活化增殖作用也降低。未转染和空质粒转染的细胞裂解液对T细胞的活化增殖有促进作用,而用反义核酸技术下调星形胶质细胞agrin表达后,星形胶质细胞裂解液对T细胞增殖的促进作用也随之下降,进一步证实agrin表达水平的下调可影响T细胞的活化和增殖。结论CVB3感染星形胶质细胞后agrin表达水平下调,降低对T细胞活化增殖的能力,这可能是CVB3病毒性脑炎中,病毒逃逸机体免疫清除的一种机制。展开更多
Common additives in plastics such as bisphenol A (BPA) or phthalates like di-(2-ethylhexyl) phthalate (DEHP) are environmental estrogens that have been shown to be endocrine disruptors in some experimental animal mode...Common additives in plastics such as bisphenol A (BPA) or phthalates like di-(2-ethylhexyl) phthalate (DEHP) are environmental estrogens that have been shown to be endocrine disruptors in some experimental animal models. This project used the C2C12 cell culture model to examine how exposure to BPA or DEHP affects two aspects of skeletal muscle development, the fusion of myoblasts into myotubes and agrin-induced clustering of acetylcholine receptors (AChRs). During myotube formation AChRs cluster spontaneously. Treatment with motor neuron derived agrin increases the frequency of AChR clusters through an agrin signaling pathway that also clusters other postsynaptic components of the neuromuscular synapse. For this project C2C12 cells were exposed to BPA or DEHP while myoblasts fused into myotubes. After exposure to 10 μM BPA or 100 μM DEHP the frequency of agrin-induced AChR clusters decreased. In addition, myotube formation decreased as a higher percentage of nuclei remained in myoblasts. Furthermore, BPA or DEHP reduced the amount of the myogenic regulatory factor myogenin. This suggests that BPA and DEHP decrease AChR clustering by reducing myogenin. Moreover, plastic additives like BPA and DEHP may pose a risk for skeletal muscle development in humans.展开更多
转移、侵袭和免疫逃避是肿瘤的重要生物学特性,聚集蛋白Agrin结合低密度脂蛋白受体相关蛋白4(low density density lipoprotein receptor related protein 4,Lrp4),参与肿瘤的侵袭与迁移.此外,Agrin还促进血管形成,并通过α-肌萎缩蛋白...转移、侵袭和免疫逃避是肿瘤的重要生物学特性,聚集蛋白Agrin结合低密度脂蛋白受体相关蛋白4(low density density lipoprotein receptor related protein 4,Lrp4),参与肿瘤的侵袭与迁移.此外,Agrin还促进血管形成,并通过α-肌萎缩蛋白聚糖(α-dystroglycan)促进T细胞免疫应答,稳定免疫突触,在肿瘤的免疫微环境中扮演着重要的角色.深入研究恶性肿瘤以及免疫细胞中的Agrin,探索其作用机制,可能为肿瘤的免疫治疗提供新方向.现就Agrin的研究现状,特别是其在恶性肿瘤与免疫作用的相关方面研究进行总结与分析.展开更多
Myasthenia gravis is a rare and invalidating disease affecting the neuromuscular junction of voluntary muscles.The classical form of this autoimmune disease is characterized by the presence of antibodies against the m...Myasthenia gravis is a rare and invalidating disease affecting the neuromuscular junction of voluntary muscles.The classical form of this autoimmune disease is characterized by the presence of antibodies against the most abundant protein in the neuromuscular junction,the nicotinic acetylcholine receptor.Other variants of the disease involve autoimmune attack of non-receptor scaffolding proteins or enzymes essential for building or maintaining the integrity of this peripheral synapse.This review summarizes the participation of the above proteins in building the neuromuscular junction and the destruction of this cholinergic synapse by autoimmune aggression in myasthenia gravis.The review also covers the application of a powerful biophysical technique,superresolution optical microscopy,to image the nicotinic receptor in live cells and follow its motional dynamics.The hypothesis is entertained that anomalous nanocluster formation by antibody crosslinking may lead to accelerated endocytic internalization and elevated turnover of the receptor,as observed in myasthenia gravis.展开更多
Amyotrophic lateral sclerosis(ALS) is a devastating motoneuron disease,in which lower motoneurons lose control of skeletal muscles.Degeneration of neuromuscular junctions(NMJs) occurs at the initial stage of ALS.Dipep...Amyotrophic lateral sclerosis(ALS) is a devastating motoneuron disease,in which lower motoneurons lose control of skeletal muscles.Degeneration of neuromuscular junctions(NMJs) occurs at the initial stage of ALS.Dipeptide repeat proteins(DPRs) from G4C2repeat-associated non-ATG(RAN) translation are known to cause C9orf72-associated ALS(C9-ALS).However,DPR inclusion burdens are weakly correlated with neurodegenerative areas in C9-ALS patients,indicating that DPRs may exert cell non-autonomous effects,in addition to the known intracellular pathological mechanisms.Here,we report that poly-GA,the most abundant form of DPR in C9-ALS,is released from cells.Local administration of poly-GA proteins in peripheral synaptic regions causes muscle weakness and impaired neuromuscular transmission in vivo.The NMJ structure cannot be maintained,as evidenced by the fragmentation of postsynaptic acetylcholine receptor(AChR) clusters and distortion of presynaptic nerve terminals.Mechanistic study demonstrated that extracellular poly-GA sequesters soluble Agrin ligands and inhibits Agrin-MuSK signaling.Our findings provide a novel cell non-autonomous mechanism by which poly-GA impairs NMJs in C9-ALS.Thus,targeting NMJs could be an early therapeutic intervention for C9-ALS.展开更多
文摘目的检测柯萨奇B3病毒(coxsackievirus group B type3,CVB3)感染体外培养的星形胶质细胞后集聚蛋白(agrin)的表达变化及其意义。方法采用免疫细胞化学的方法鉴定培养的星形胶质细胞,在显微镜下观察CVB3感染后的细胞形态,并用RT-PCR方法扩增CVB3RNA的正负链以确证感染成功,用RT-PCR检测CVB3感染细胞后agrin的动态表达变化。用脂质体将agrin反义质粒pcDNA3-As-AG转染到星形胶质细胞,并用RT-PCR检测转染的细胞中agrin的表达。3H-TdR掺入法测定CVB3不同感染时间点的星形胶质细胞裂解液和经agrin反义质粒pcDNA-As-AG转染细胞后的细胞裂解液对T细胞增殖的影响。结果(1)CVB3感染星形胶质细胞后agrin的表达水平下调。(2)病毒感染后随着agrin表达量的降低,星形胶质细胞裂解液对T细胞的活化增殖作用也降低。未转染和空质粒转染的细胞裂解液对T细胞的活化增殖有促进作用,而用反义核酸技术下调星形胶质细胞agrin表达后,星形胶质细胞裂解液对T细胞增殖的促进作用也随之下降,进一步证实agrin表达水平的下调可影响T细胞的活化和增殖。结论CVB3感染星形胶质细胞后agrin表达水平下调,降低对T细胞活化增殖的能力,这可能是CVB3病毒性脑炎中,病毒逃逸机体免疫清除的一种机制。
文摘Common additives in plastics such as bisphenol A (BPA) or phthalates like di-(2-ethylhexyl) phthalate (DEHP) are environmental estrogens that have been shown to be endocrine disruptors in some experimental animal models. This project used the C2C12 cell culture model to examine how exposure to BPA or DEHP affects two aspects of skeletal muscle development, the fusion of myoblasts into myotubes and agrin-induced clustering of acetylcholine receptors (AChRs). During myotube formation AChRs cluster spontaneously. Treatment with motor neuron derived agrin increases the frequency of AChR clusters through an agrin signaling pathway that also clusters other postsynaptic components of the neuromuscular synapse. For this project C2C12 cells were exposed to BPA or DEHP while myoblasts fused into myotubes. After exposure to 10 μM BPA or 100 μM DEHP the frequency of agrin-induced AChR clusters decreased. In addition, myotube formation decreased as a higher percentage of nuclei remained in myoblasts. Furthermore, BPA or DEHP reduced the amount of the myogenic regulatory factor myogenin. This suggests that BPA and DEHP decrease AChR clustering by reducing myogenin. Moreover, plastic additives like BPA and DEHP may pose a risk for skeletal muscle development in humans.
文摘转移、侵袭和免疫逃避是肿瘤的重要生物学特性,聚集蛋白Agrin结合低密度脂蛋白受体相关蛋白4(low density density lipoprotein receptor related protein 4,Lrp4),参与肿瘤的侵袭与迁移.此外,Agrin还促进血管形成,并通过α-肌萎缩蛋白聚糖(α-dystroglycan)促进T细胞免疫应答,稳定免疫突触,在肿瘤的免疫微环境中扮演着重要的角色.深入研究恶性肿瘤以及免疫细胞中的Agrin,探索其作用机制,可能为肿瘤的免疫治疗提供新方向.现就Agrin的研究现状,特别是其在恶性肿瘤与免疫作用的相关方面研究进行总结与分析.
文摘Myasthenia gravis is a rare and invalidating disease affecting the neuromuscular junction of voluntary muscles.The classical form of this autoimmune disease is characterized by the presence of antibodies against the most abundant protein in the neuromuscular junction,the nicotinic acetylcholine receptor.Other variants of the disease involve autoimmune attack of non-receptor scaffolding proteins or enzymes essential for building or maintaining the integrity of this peripheral synapse.This review summarizes the participation of the above proteins in building the neuromuscular junction and the destruction of this cholinergic synapse by autoimmune aggression in myasthenia gravis.The review also covers the application of a powerful biophysical technique,superresolution optical microscopy,to image the nicotinic receptor in live cells and follow its motional dynamics.The hypothesis is entertained that anomalous nanocluster formation by antibody crosslinking may lead to accelerated endocytic internalization and elevated turnover of the receptor,as observed in myasthenia gravis.
基金supported by the National Key Research and Development Program of China (2022YFF1000500 to K.Z. and2021YFA1101100 to C.S.)Zhejiang Provincial Natural Science Foundation(LZ22C110002 to C.S.)National Natural Science Foundation of China(32271031 to K.Z. and 82230038, 31871203, and 32071032 to C.S.)。
文摘Amyotrophic lateral sclerosis(ALS) is a devastating motoneuron disease,in which lower motoneurons lose control of skeletal muscles.Degeneration of neuromuscular junctions(NMJs) occurs at the initial stage of ALS.Dipeptide repeat proteins(DPRs) from G4C2repeat-associated non-ATG(RAN) translation are known to cause C9orf72-associated ALS(C9-ALS).However,DPR inclusion burdens are weakly correlated with neurodegenerative areas in C9-ALS patients,indicating that DPRs may exert cell non-autonomous effects,in addition to the known intracellular pathological mechanisms.Here,we report that poly-GA,the most abundant form of DPR in C9-ALS,is released from cells.Local administration of poly-GA proteins in peripheral synaptic regions causes muscle weakness and impaired neuromuscular transmission in vivo.The NMJ structure cannot be maintained,as evidenced by the fragmentation of postsynaptic acetylcholine receptor(AChR) clusters and distortion of presynaptic nerve terminals.Mechanistic study demonstrated that extracellular poly-GA sequesters soluble Agrin ligands and inhibits Agrin-MuSK signaling.Our findings provide a novel cell non-autonomous mechanism by which poly-GA impairs NMJs in C9-ALS.Thus,targeting NMJs could be an early therapeutic intervention for C9-ALS.
