Chaumontet C, Mazzoleni G, Decaens C, Bex V, Cassio D, Martel P
Laboratoire de Nutrition et Sécurité Alimentaire, Institut National de la Recherche Agronomique, Centre de Recherche de Jouy-en-Josas, France.
Hepatology. 1998 Jul;28(1):164-72. doi: 10.1002/hep.510280122.
Gap junction intercellular communication (GJIC) plays an essential role in the control of growth, differentiation, and functions of different tissues. The expression of connexins (Cxs), the structural proteins of gap junctions, is developmentally regulated and tissue-specific. In vivo hepatocytes express Cx32 and Cx26. Most currently available in vitro hepatic cell systems express Cx43 instead of the expected Cxs. This work analyzes the GJIC competence and Cx expression of the highly differentiated and polarized hepatoma-derived hybrid cell lines, WIF 12-1 and WIF-B. It shows (using two dye transfer assays) that both lines communicate efficiently and that the acquisition of GJIC competence precedes the formation of bile canaliculi. Interestingly, these cells communicate via Cx32 expression, whereas Cx26 and Cx43 are not expressed, as demonstrated by Western and Northern blotting, immunocytochemistry, and confocal microscopy. The human fibroblast W138 parent communicates via Cx43, whereas the rat hepatoma parent Fao and the subclone WIF 12-1 TGdelta, that has lost the human X chromosome, do not communicate, the expression of Cx32 being restricted to the mRNA in these two lines. The GJIC competence of WIF cells could thus result from the activation of the human X chromosome-linked Cx32 gene.
间隙连接细胞间通讯（GJIC）在不同组织的生长、分化和功能控制中起着至关重要的作用。连接蛋白（Cxs）作为间隙连接的结构蛋白，其表达受到发育调控且具有组织特异性。在体内，肝细胞表达Cx32和Cx26。目前大多数体外肝细胞系统表达的是Cx43，而非预期的连接蛋白。这项研究分析了高度分化且极化的肝癌衍生杂交细胞系WIF 12 - 1和WIF - B的GJIC能力及连接蛋白表达情况。研究表明（通过两种染料转移试验），这两种细胞系都能高效通讯，且GJIC能力的获得先于胆小管的形成。有趣的是，这些细胞通过Cx32的表达进行通讯，而Cx26和Cx43未表达，这通过蛋白质免疫印迹法、Northern印迹法、免疫细胞化学和共聚焦显微镜得以证实。人成纤维细胞W138亲本通过Cx43进行通讯，而大鼠肝癌亲本Fao以及丢失了人类X染色体的亚克隆WIF 12 - 1 TGdelta则不进行通讯，Cx32的表达在这两个细胞系中仅限于mRNA水平。因此，WIF细胞的GJIC能力可能源于人类X染色体连锁的Cx32基因的激活。
