Nagy J I, Hossain M Z, Hertzberg E L, Marotta C A
Department of Physiology, University of Manitoba, Winnipeg, Manitoba, Canada.
J Neurosci Res. 1996 Apr 15;44(2):124-32. doi: 10.1002/(SICI)1097-4547(19960415)44:2<124::AID-JNR4>3.0.CO;2-F.
Previous studies have shown that PC12 cells overexpressing beta/A4 amyloid peptide display altered morphology characterized by pronounced membrane ruffling and extensive intercellular appositions. Having observed other cell types in which these features accompany increased connexin43 (Cx43) production and gap junctional communication, we examined Cx43 in normal and beta/A4-transfected PC12 cells. Studies of two beta/A4-transfected PC12 clones revealed an induction of Cx43 expression by Western blotting, intracellular and plasma membrane-associated Cx43 in some cells of cultures processed by immunofluorescence, dye-transfer between some cells microinjected with Lucifer Yellow, and gap junctions between cells examined by EM. Normal and vector-transfected PC12 cells exhibited none of these properties. Increased immunofluorescence in some clusters of beta/A4-transfected cells was also observed with a monoclonal antibody against connexin32. The results suggest that beta/A4 amyloid peptide may cause aberrant intercellular communication and gap junction formation through induction or increased expression of connexins in cells that are not normally coupled or only poorly coupled by gap junctions.
先前的研究表明，过表达β/A4淀粉样肽的PC12细胞呈现出形态改变，其特征为明显的膜皱襞和广泛的细胞间并列。在观察到其他细胞类型中这些特征伴随着连接蛋白43（Cx43）产生增加和间隙连接通讯后，我们检测了正常PC12细胞和转染β/A4的PC12细胞中的Cx43。对两个转染β/A4的PC12克隆的研究显示，通过蛋白质印迹法可诱导Cx43表达，在经免疫荧光处理的培养物的一些细胞中可检测到细胞内和质膜相关的Cx43，在一些注射了荧光素黄的细胞之间可观察到染料转移，通过电子显微镜检查可发现细胞间存在间隙连接。正常PC12细胞和转染载体的PC12细胞均未表现出这些特性。用抗连接蛋白32单克隆抗体也观察到转染β/A4的细胞的一些簇中免疫荧光增加。结果表明，β/A4淀粉样肽可能通过诱导或增加连接蛋白的表达，在通常不通过间隙连接耦合或仅微弱耦合的细胞中导致异常的细胞间通讯和间隙连接形成。
