Investigating the role of the complement system in cardiac regeneration

项目总结： 由于成体心脏的低增殖率，哺乳动物心脏的再生能力有限。 心肌细胞。然而，在新生小鼠的心脏中发现了一个狭窄的再生窗口， 其中小鼠能够成功地在组织和功能水平上再生它们的心脏 在受伤之后。在Lee实验室的跨物种转录筛选中，炎症反应 包括补体受体在内的基因在再生心脏中以一种保守的方式上调 三种模式生物--紫杉醇、小鼠和斑马鱼。最高表达的炎性反应 基因包括补体成分的G蛋白偶联受体(GPCR)、补体5a受体 (C5aR1)和补体3a受体(C3aR)。补体系统是先天免疫的一部分。 清除异物的系统和功能。早期免疫反应的激活是一个共同的特征 在模式生物的再生心脏观察到，与C5aR1和C5aR1的上调一致 观察到C3aR。C5aR1是一种GPCR，其功能是C5a的补体受体，由 补体成分的蛋白水解性切割5.根尖切除后对C5aR1的药理抑制 结果在所有三个被研究的模型生物中，紫杉醇， 老鼠和斑马鱼。我建议研究补体激活在小鼠心脏中的作用 再生，阐明启动有效修复和心肌细胞的分子机制 哺乳动物心脏损伤后的增殖。为了理解C5aR1的作用，我将利用全局 C5aR1基因缺失小鼠模型评估心脏根尖切除后的细胞再生， C5aR1野生型和C5aR1基因敲除小鼠的组织和功能水平。我建议评估 C5aR1野生型和基因敲除小鼠心肌细胞增殖的研究 损伤心脏中启动心肌细胞增殖和有效再生的分子事件。 此外，我将通过药物抑制来研究C3aR在心脏早期再生中的作用。 和C3aR基因敲除小鼠。此外，我将在非再生小鼠模型上进行实验(7- )，以研究补体信号(C3和C5)的急性激活是否会增加 损伤后心肌细胞增殖。这些研究可能会定义一种早期的机制途径 对启动心肌细胞增殖至关重要的事件。

Project summary: The mammalian heart has a limited regenerative potential due to the low proliferation rate of adult cardiomyocytes. However, a narrow regenerative window has been identified in the neonatal murine heart, wherein mice are able to successfully regenerate their hearts both at the tissue and functional level following injury. In a cross-species transcriptomic screen in the Lee laboratory, inflammatory response genes including complement receptors were upregulated in a conserved manner in the regenerating heart of three model organisms – axolotl, mouse and zebrafish. The most-upregulated inflammatory response genes include G-protein coupled receptors (GPCR) for complement components, complement 5a receptor (C5aR1) and complement 3a receptor (C3aR). The complement system is part of the innate immune system and functions to clear foreign material. Activation of an early immune response is a shared feature observed in the regenerating heart of model organisms, consistent with the upregulation of C5aR1 and C3aR observed. C5aR1 is a GPCR that functions as a complement receptor for C5a, generated by proteolytic cleavage of complement component 5. Pharmacologic inhibition of C5aR1 after apical resection results in an impaired cardiomyocyte proliferative response in all three model organisms studied – axolotl, mouse and zebrafish. I propose to investigate the role of complement activation in murine cardiac regeneration, to elucidate the molecular mechanisms that initiate effective repair and cardiomyocyte proliferation in the mammalian heart following injury. To understand the role of C5aR1, I will utilize global genetic deletion mouse model of C5aR1 to assess cardiac regeneration after apical resection at the cellular, tissue and functional level in C5aR1 wild-type and C5aR1 knock-out mice. I propose to assess cardiomyocyte proliferation in C5aR1 wild-type and knock-out mice to understand the sequence of molecular events in the injured heart that initiate cardiomyocyte proliferation and effective regeneration. Furthermore, I will investigate the role of C3aR in early cardiac regeneration using pharmacologic inhibition and C3aR knock-out mice. In addition, I will perform experiments in non-regenerative murine models (7- day-old mice) to investigate if acute activation of complement signaling (C3 and C5) will increase cardiomyocyte proliferation following injury. These studies will likely define a mechanistic pathway of early events critical for the initiation of cardiomyocyte proliferation in the myocardium.