Institut National de la Santé et de la Recherche Médicale (INSERM U753), Institut Fédératif de Recherche 54 (IFR54), Institut Gustave Roussy, 39 Rue Camille Desmoulins, 94805, Villejuif, France.
J Mol Med (Berl). 2013 Oct;91(10):1207-20. doi: 10.1007/s00109-013-1058-5. Epub 2013 Jun 7.
Gap junctions (GJs) enable intercellular communication between adjacent cells through channels of connexins. Using a three-dimensional construct, we previously showed that endothelial and tumor cells formed GJs, allowing melanoma-specific T lymphocytes to recognize and kill melanoma-derived endothelial cells. We demonstrate here on histological sections of melanoma biopsies that GJ formation occurs in vivo between tumor and endothelial cells and between T lymphocytes and target cells. We also show an in vitro increase of GJ formation in melanoma and endothelial cells following dacarbazin and interferon gamma (IFN-γ) treatment or hypoxic stress induction. Our data indicate that although connexin 43 (Cx43), the main GJ protein of the immune system, was localized at the immunological synapse between T lymphocyte and autologous melanoma cells, its over-expression or inhibition of GJs does not interfere with cytotoxic T lymphocyte (CTL) clone lytic function. In contrast, we showed that inhibition of GJs by oleamide during stimulation of resting PBMCs with Melan-A natural and analog peptides resulted in a decrease in antigen (Ag) specific CD8(+) T lymphocyte induction. These Ag-specific CD8(+) cells displayed paradoxically stronger reactivity as revealed by CD107a degranulation and IFN-γ secretion. These findings indicate that Cx43 does not affect lytic function of differentiated CTL, but reveal a major role for GJs in the regulation of antigen CD8(+)-naïve T lymphocyte activation.
GJ formation occurs in vivo between T lymphocytes and tumor cells Cx43 localized at the immunological synapse between T and autologous melanoma cells Inhibition of GJs resulted in a decrease in Ag-specific CD8(+) T lymphocyte induction A role for GJs in the regulation of antigen CD8(+)-naïve T lymphocyte activation.
间隙连接（GJ）通过连接蛋白的通道使相邻细胞之间进行细胞间通讯。我们之前使用三维构建体表明，内皮细胞和肿瘤细胞形成 GJ，使黑色素瘤特异性 T 淋巴细胞能够识别和杀死源自黑色素瘤的内皮细胞。我们在此证明，在黑色素瘤活检的组织切片中，肿瘤细胞和内皮细胞之间以及 T 淋巴细胞和靶细胞之间存在 GJ 形成。我们还表明，在体外，在用达卡巴嗪和干扰素 γ（IFN-γ）处理或缺氧应激诱导后，黑色素瘤和内皮细胞中的 GJ 形成增加。我们的数据表明，尽管连接蛋白 43（Cx43）是免疫系统的主要 GJ 蛋白，但它位于 T 淋巴细胞和自体黑色素瘤细胞之间的免疫突触中，但其过表达或 GJ 抑制并不干扰细胞毒性 T 淋巴细胞（CTL）克隆的裂解功能。相反，我们表明，在用 Melan-A 天然和类似肽刺激静止 PBMC 时，通过油酸酰胺抑制 GJ 会导致抗原（Ag）特异性 CD8+T 淋巴细胞诱导减少。这些 Ag 特异性 CD8+细胞显示出更强的反应性，如 CD107a 脱颗粒和 IFN-γ 分泌所揭示的那样。这些发现表明 Cx43 不影响分化的 CTL 的裂解功能，但揭示了 GJ 在调节抗原 CD8+幼稚 T 淋巴细胞激活中的主要作用。
T 淋巴细胞与肿瘤细胞之间在体内发生 GJ Cx43 定位于 T 与自体黑色素瘤细胞之间的免疫突触 抑制 GJ 导致 Ag 特异性 CD8+T 淋巴细胞诱导减少 GJ 在调节抗原 CD8+幼稚 T 淋巴细胞激活中的作用。
