Cell biology of blood-nerve barrier, using cultured endothelial cell of endoneurial microvessel origin

免疫球蛋白渗透和/或活化淋巴细胞迁移到周围神经系统（PNS）实质是发生格林-巴利综合征、IgM神经病变和慢性炎性脱髓鞘性多根神经病变等PNS免疫紊乱的最初关键步骤。因此，了解内皮细胞的细胞特性是很重要的，因为这些细胞构成了血神经屏障（BNB）的主体。为此，我们开发了一种从牛马尾分离培养pnmec纯群体的方法（Kanda T et al., J Neurosci Res 1997），然后建立了体外形成BNB模型的技术。使用体外BNB模型，我们发现：(1)神经内膜周细胞增强了该模型的屏障功能，可能对BNB的完整性至关重要（Iwasaki T et al., J Med Dent Sci 1999）；(2)通过该模型发现，VEGF、IL-1 β、TNF α、TGF β等多种细胞因子在炎性神经病的发生发展中发挥关键作用，降低了膜阻力，增加了放射性示踪剂（胰岛素）；(3)抗gm1单克隆抗体也能减弱BNB的功能（Kanda T et al.，提交）。使用神经病变患者的血清和阐明暴露于抗gm1抗体后BNB松动的信号通路的进一步实验正在进行中。

Penetration of immunoglobulins and/or migration of activated lymphocytes into peripheral nervous system (PNS) parenchyma are the initial key steps to develop immunological disorders of PNS including Guillain-Barre syndrome, IgM neuropathy and chronic inflammatory demyelinating polyradiculoneuropathy. Hence, it is important to know the cellular property of endothelial cells of endoneurial tissue origin (PnMEC) because these cells constitute the bulk of the blood-nerve barrier (BNB). For this purpose we developed a method to isolate and culture pure populations of PnMECs from bovine cauda equina (Kanda T et al., J Neurosci Res 1997) and then established the technique to form in vitro BNB model. Using the BNB in vitro model, we found : (1) endoneurial pericytes enhance the barrier function of this model and may be essential for the BNB integrity (Iwasaki T et al., J Med Dent Sci 1999) ; (2) Various cytokines including VEGF, IL-1 beta, TNF alpha, and TGF beta, which are supposed to play key role in the development of inflammatory neuropathies, are found to decrease the membrane resistance and increase the radioactive tracer (inulin) through this model ; (3) Anti-GM1 monoclonal antibody also weaken the BNB function (Kanda T et al., submitted). Further experiments using sera of neuropathy patients and those to clarify signaling pathways underlying loosening of the BNB following exposure to anti-GM1 antibody are underway.