Jin Chunhua, Cleveland Joseph C, Ao Lihua, Li Jilin, Zeng Qingchun, Fullerton David A, Meng Xianzhong
Department of Surgery, University of Colorado Denver, Aurora, Colorado, United States of America Center for Experimental Medicine, Southern Medical University, Guangzhou, China.
Department of Surgery, University of Colorado Denver, Aurora, Colorado, United States of America.
Mol Med. 2014 Jun 9;20(1):280-9. doi: 10.2119/molmed.2014.00058.
The myocardial inflammatory response contributes to cardiac functional injury associated with heart surgery obligating global ischemia/reperfusion (I/R). Toll-like receptors (TLRs) play an important role in the mechanism underlying myocardial I/R injury. The aim of this study was to examine the release of small constitutive heat shock proteins (HSPs) from human and mouse myocardium after global ischemia and examine the role of extracellular small HSP in myocardial injury. HSP27 release was assessed by enzyme-linked immunosorbent assay. Anti-HSP27 was applied to evaluate the role of extracellular HSP27 in the postischemic inflammatory response and functional injury in mouse hearts. Isolated hearts and cultured coronary vascular endothelial cells were exposed to recombinant HSP27 to determine its effect on proinflammatory signaling and production of proinflammatory mediators. HSP27 levels were markedly elevated in coronary sinus blood of patients and in coronary effluent of mouse hearts after global ischemia. Neutralizing extracellular HSP27 suppressed myocardial nuclear factor (NF)-κB activation and interleukin (IL)-6 production and improved cardiac function in mouse hearts. Perfusion of HSP27 to mouse hearts induced NF-κB activation and IL-6 production and depressed contractility. Further, recombinant HSP27 induced NF-κB phosphorylation and upregulated monocyte chemoattractant protein (MCP)-1 and intercellular adhesion molecule (ICAM)-1 production in both human and mouse coronary vascular endothelial cells. TLR2 knockout (KO) or TLR4 mutation abolished NF-κB phosphorylation and reduced MCP-1 and ICAM-1 production induced by extracellular HSP27 in endothelial cells. In conclusion, these results show that the myocardium releases HSP27 after global ischemia and that extracellular HSP27 is proinflammatory and contributes to the inflammatory mechanism of myocardial functional injury. Both TLR2 and TLR4 are involved in mediating the proinflammatory effect of extracellular HSP27.
心肌炎症反应会导致与心脏手术相关的心脏功能损伤，而心脏手术必然会引起整体缺血/再灌注（I/R）。Toll样受体（TLR）在心肌I/R损伤的潜在机制中起重要作用。本研究的目的是检测整体缺血后人及小鼠心肌中小组成型热休克蛋白（HSP）的释放，并研究细胞外小HSP在心肌损伤中的作用。通过酶联免疫吸附测定法评估HSP27的释放。应用抗HSP27来评估细胞外HSP27在小鼠心脏缺血后炎症反应和功能损伤中的作用。将离体心脏和培养的冠状动脉血管内皮细胞暴露于重组HSP27，以确定其对促炎信号传导和促炎介质产生的影响。整体缺血后，患者冠状窦血和小鼠心脏冠状流出液中的HSP27水平显著升高。中和细胞外HSP27可抑制小鼠心脏中的心肌核因子（NF）-κB活化和白细胞介素（IL）-6产生，并改善心脏功能。向小鼠心脏灌注HSP27可诱导NF-κB活化和IL-6产生，并降低收缩性。此外，重组HSP27可诱导人及小鼠冠状动脉血管内皮细胞中的NF-κB磷酸化，并上调单核细胞趋化蛋白（MCP）-1和细胞间黏附分子（ICAM）-1的产生。TLR2基因敲除（KO）或TLR4突变可消除细胞外HSP27在内皮细胞中诱导的NF-κB磷酸化，并减少MCP-1和ICAM-1的产生。总之，这些结果表明，整体缺血后心肌会释放HSP27，并且细胞外HSP27具有促炎作用，有助于心肌功能损伤的炎症机制。TLR2和TLR4均参与介导细胞外HSP27的促炎作用。
