α7 nAChR在上皮组织的表达及其功能的研究进展

Study of the Expression and Function of α7 nAChR in Epithelial Tissues

α7 nAChR是配体门控离子通道蛋白超家族的典型代表,烟碱型乙酰胆碱受体的一个重要亚型,是复杂的五聚体跨膜蛋白,介导Na+、Ca2+流入,K+流出,尤以对Ca2+通透性高。α7 nAChR分布广泛且功能多样,不仅分布于中枢和外周神经系统,介导神经元的快速突触传递,其在许多非神经元细胞和组织中亦有表达,包括内皮细胞,支气管上皮细胞,皮肤角蛋白细胞,膀胱上皮细胞,血管平滑肌等,并参与其功能调节及功能障碍相关疾病的病理生理过程,如可调节细胞质运动和细胞间黏附,细胞增殖,血管生成以及肿瘤的侵袭和迁移。本文主要介绍烟碱型乙酰胆碱受体α7亚型在不同胚层来源的上皮组织细胞中的表达及其功能特征,以期通过激活或抑制α7 nAChR的表达来降低与其密切相关疾病的发生率。

Nicotinic acetylcholine receptors （nAChRs） belong to the ligand-gated ion channel super family. These receptors have the characteristic of high permeability for Ca^2＋ while the α7 subunit is a very important type for this super family. It is a complex pentamer transmembrane protein and besides Ca^2＋, the receptor also mediate the influx of Na^＋ and the outflow of K^＋. α7 nAChR is widely distributed in many tissues and organs with multiply functions. They not only exit in central and peripheral nervous systems that mediate fast synaptie transmission in neurons, but also have been found on non-neuronal cells and tissues such as endothelial cells （ECs）, bronchial epithelial cells, skin keratinoeytes, urinary bladder epithelial cells and vascular smooth muscle cells. In these non-neuronal cells and tissues, the receptor is involved in pathophysiological process of functional regulation and dysfunction related diseases. The mecha- nism can be attributed to the regulation of cytoplasmic movement, intercellular adhesion, cell proliferation, angiogenesis, the invasion and metastasis for tumor. This review mainly describes the expression and functional characteristics of nicotinic cholinergic receptor alpha 7 subtype which expressed in three germ layers derived cells and tissues in the hope of providing some theoretical theories for clinical work through regulating its expression level in different tissues.