Staphylococcus aureus-derived peptidoglycan induces Cx43 expression and functional gap junction intercellular communication in microglia
Staphylococcus aureus-derived peptidoglycan induces Cx43 expression and functional gap junction intercellular communication in microglia
复制标题
DOI：
10.1111/j.1471-4159.2005.03384.x
复制
发表时间：
2005-10-01
影响因子：
4.7
通讯作者：
Kielian, T
中科院分区：
文献类型：
--
作者：
Garg, S;Syed, MM;Kielian, T
缝隙连接作为细胞间的通道，允许小分子分子(高达1 kDa)的交换，包括离子、代谢前体和第二信使。小胶质细胞能够识别来源于中枢神经系统常见病原体金黄色葡萄球菌外壁的肽聚糖(PGN)，并在众多促炎介质的强烈作用下做出反应。根据最近的报道，肿瘤坏死因子-α和干扰素-γ能够诱导巨噬细胞和小胶质细胞的缝隙连接偶联，从PGN激活的小胶质细胞释放的促炎介质可能能够诱导小胶质细胞缝隙连接通讯。在这项研究中，我们研究了金黄色葡萄球菌来源的PGN对Cx43的影响，Cx43是小胶质细胞缝隙连接通道中的主要连接蛋白，并通过单细胞微量注射荧光黄(LY)进行功能缝隙连接通讯。原代小鼠小胶质细胞暴露于PGN后，Cx43mRNA和蛋白表达显著增加。LY显微注射研究表明，经PGN处理的小胶质细胞是通过缝隙连接实现功能偶联的，缝隙连接阻滞剂18-α-甘草次酸逆转了激活诱导的染料偶联，证实了这种偶联的特异性。与PGN激活的小胶质细胞相比，未受刺激的细胞始终没有表现出LY染料偶联。这些结果表明，刺激PGN可以诱导形成功能性的小胶质细胞合体，提示这些细胞可能能够通过缝隙连接细胞间通讯影响中枢细菌感染背景下的神经炎性反应。
Gap junctions serve as intercellular conduits that allow the exchange of small molecular weight molecules (up to 1 kDa) including ions, metabolic precursors and second messengers. Microglia are capable of recognizing peptidoglycan (PGN) derived from the outer cell wall of Staphylococcus aureus, a prevalent CNS pathogen, and respond with the robust elaboration of numerous pro-inflammatory mediators. Based on recent reports demonstrating the ability of tumor necrosis factor-alpha and interferon-gamma to induce gap junction coupling in macrophages and microglia, it is possible that pro-inflammatory mediators released from PGN-activated microglia are capable of inducing microglial gap junction communication. In this study, we examined the effects of S. aureus-derived PGN on Cx43, the major connexin in microglial gap junction channels, and functional gap junction communication using single-cell microinjections of Lucifer yellow (LY). Exposure of primary mouse microglia to PGN led to a significant increase in Cx43 mRNA and protein expression. LY microinjection studies revealed that PGN-treated microglia were functionally coupled via gap junctions, the specificity of which was confirmed by the reversal of activation-induced dye coupling by the gap junction blocker 18-alpha-glycyrrhetinic acid. In contrast to PGN-activated microglia, unstimulated cells consistently failed to exhibit LY dye coupling. These results indicate that PGN stimulation can induce the formation of a functional microglial syncytium, suggesting that these cells may be capable of influencing neuroinflammatory responses in the context of CNS bacterial infections through gap junction intercellular communication.