Neurexin与Neuroligin基因在肠神经系统发育中的作用机制及临床价值

The pathogenesis of many diseases about the developmental defects of enteric nervous system(ENS) is still not clear．We kown very little about the function of the synapse in ENS,though Neurexin and Neuroligin have been confirmed that they play an important role in the development and function of synapse in central nervous system(CNS).We kown that ENS has a close relationship with CNS and the synaptic mechanism of ENS must be very similar with CNS.As a result,the functional disturbance of gastrointestinal tract could be indicated by the dysplasia and disfunction of synapse in ENS.We have preliminarily confirmed by double immunofluorescence technique that Neurexin and Neuroligin are expressed in the ENS of human and rodents,which show that Neurexin and Neuroligin also play an important role in the synapic function．Followed that， we will further sdudy the role of Neurexin and Neuroligin in the development of ENS and the pathogenesis of many diseases by the experimental methods of in situ hybridization，RT-PCR,real-time fluorescence quantitative PCR,gene sequencing,cell culture,serological detection and so on.Finally,we will reveal the formation,development and function of synapse in ENS,further discuss the developmental defects of synapse and elucidate the pathogenesis of diseases with functional disturbance of gastrointestinal such as Hischsprung's disease(HD) which has important significance to the diagnosis,treatment and prevention of these diseases.

临床上与肠神经系统缺陷有关疾病很多，但大多数病理生理并不清楚。尽管在中枢神经系统(CNS)中，Neurexin 与Neuroligin基因已经被证实支配突触的发生、发育与功能，但对肠神经系统(ENS)突触的构成知之甚少。既然ENS与CNS关系密切，其突触发生机理也极可能十分相似，那ENS中突触功能和发育的异常就可以解释胃肠道的机能紊乱。笔者已初步证实：Neurexin与Neuroligin基因在鼠类及人体肠管都有表达，说明它们对ENS突触功能也起重要作用。下一步将对Neurexin与Neuroligin基因与肠神经系统的发育以及疾病的发生机理作深入研究。基础实验与临床研究相结合，将对ENS突触的形成、发育、功能有很好的揭示，对ENS发育缺陷做出深入探讨，对胃肠动力性障碍等肠神经缺陷性疾病的机理做出一定的解释，对先天性巨结肠等相关疾病的诊断、治疗与预防有重大意义。

按照申报计划书的计划内容，我们经过几年的努力取得了一定的实验数据和研究成果，具体如下：. 1.neuroligin-1和neuroligin-2蛋白表达在肠神经系统的神经节细胞，同时它们的表达量在这三段不同肠管中是逐渐降低的。. 2.谷氨酸在先天性巨结肠患儿血清中的含量明显低于对照组患儿的血清含量，而GABA在先天性巨结肠患儿血清中的含量明显高于对照组患儿的血清含量。. 3.Neuroligin基因/蛋白在cajal细胞有表达，neuroligin蛋白在不同肠段来源的cajal细胞的表达量也是呈现由扩张段到移行段再到狭窄段逐渐降低的趋势。. 4.在体外细胞培养增值过程中，NRXN1和NLGN1基因可以促进自身的表达和自身细胞的增殖，但是对对方基因、蛋白的表达和对方细胞的增殖起到的是抑制作用。. 5.在巨结肠的临床标本检测和实验动物胚胎的检测中，我们发现NLGN和NRXN基因与肠神经系统的发育有关，而肠神经系统发育的不完善导致了儿童先天性巨结肠的发病。. 通过以上研究成果我们认为该课题研究有一定的科学意义，通过研究我们认为NRXN1和NLGN1基因可以促进自身的表达和自身细胞的增殖，但是对对方基因、蛋白的表达和对方细胞的增殖起到的是抑制作用。这种促进或者抑制的作用可能为探讨肠神经系统神经细胞突触间的作用机制提供了一定的依据。而NLGN和NRXN基因与肠神经系统的发育有关，而肠神经系统发育的不完善导致了儿童先天性巨结肠的发病。因此NLGN和NRXN基因可能在先天性巨结肠的成因中发挥了重要作用。