PKC signalling and cell-cell communication

描述(申请人提供)：在生理条件下，心肌细胞连接良好，确保快速传导。然而，在病理生理条件下，心肌细胞变得解偶联，这种适应性反应限制了有害代谢物在细胞间的传播。PKC-epsilon Null(PKCE-KO)小鼠、异构体特异性的PKC激活物和抑制肽、表达PKC异构体的腺病毒以及磷酸化特异性的抗Cx43和-PKC抗体将被用来鉴定PKC亚型，并阐明在生理条件和缺血反应中调节缝隙连接通道功能和Cx43(主要的心室缝隙连接蛋白)表达的分子事件。初步研究表明，在野生型和PKCE-KO心脏中，缺血都会导致PKC位点Ser368处Cx43的磷酸化增加。此外，与野生型相比，PKCE-KO心脏在基础(非缺血)条件下表现出Cx43表达增加，但在缝隙连接处表现出比野生型更显著的Cx43丢失。这些研究将对缺血性心脏病患者的心律失常机制产生新的见解，并有助于开发新的治疗方法来预防这些患者的心律失常。

DESCRIPTION (provided by applicant): Under physiological conditions, cardiac myocytes are well coupled ensuring rapid conduction. Under pathophysiological conditions, however, myocytes become uncoupled, an adaptive response that limits the intercellular spread of noxious metabolites. PKC-epsilon null (PKCe-KO) mice, isoform-specific PKC activator and inhibitor peptides, adenoviruses expressing PKC isoforms, and phospho-specific anti-Cx43 and -PKC antibodies will be used to identify PKC isoforms and elucidate molecular events regulating gap junction channel function and Cx43 (the major ventricular gap junction protein) expression under physiological conditions and in response to ischemia. Preliminary studies show that ischemia leads to increased phosphorylation of Cx43 at the PKC site Ser368 in both wildtype and PKCe-KO hearts. Furthermore, PKCe-KO hearts show increased expression of Cx43 under basal (non-ischemic) conditions, but exhibit more dramatic loss of Cx43 in gap junctions in response to ischemia compared to wildtype. These studies will yield new insights into mechanisms of arrhythmias in patients with ischemic heart disease and contribute to efforts to develop new therapies to prevent arrhythmias in these patients.