巨噬细胞与心房肌细胞交互作用在房颤发生和发展中的作用及机制研究

发布时间：2018-02-21 11:01

本文关键词： 房颤巨噬细胞-心房肌细胞交互作用 IL-1β QKI蛋白　出处：《浙江大学》2017年博士论文　论文类型：学位论文

【摘要】：心房颤动(房颤)是最常见的心律失常,目前认为炎症在房颤的发生和发展中起到重要作用。新近研究发现,房颤患者的心房组织内巨噬细胞浸润增加,但其表型和功能尚不明确。为回答上述问题,我们开展了如下工作:首先,我们收集并分析了房颤患者的右心耳组织,我们发现,与窦性心律对照者相比,房颤患者右心耳组织中巨噬细胞浸润增加,并且以促炎型(iNOS+,Arg1-)为主。将快速起搏后的小鼠心房肌细胞(HL-1细胞)与巨噬细胞共培养,同样可以诱导巨噬细胞向促炎型分化。另一方面,用LPS激活心房内促炎型巨噬细胞可导致小鼠及犬心房电重构增加,表现为房颤发生率的增多、有效不应期缩短及L型钙离子通道电流的减小;而使用膦酸二钠脂质体清除心房内促炎型巨噬细胞可减少LPS所致心房电重构,此结果进一步确认了促炎型巨噬细胞在房颤发生中的作用。在分子机制方面,我们发现,促炎型巨噬细胞所致心房电重构增加是通过分泌IL-1β实现的,巨噬细胞分泌IL-1β作用于心房肌细胞,导致心房肌细胞内RNA结合蛋白QKI表达下降。另一方面,与野生型促炎型巨噬细胞相比,IL-1β敲除促炎型巨噬细胞与心房肌细胞共培养后,可以部分恢复心房肌细胞的QKI表达,进一步确认了 IL-1β在促炎型巨噬细胞所致心房肌细胞QKI下调中的作用。进一步地,我们发现,心房肌细胞QKI过表达可以增加QKI与L型钙离子通道蛋白α1C亚基编码基因CACNA1C mRNA的结合,同时可以提高CACNA1C表达水平和L型钙离子通道电流,而心房肌细胞QKI敲除可减少CACNA1C表达。最后,为研究QKI的转录调控,我们进行了转录因子筛选,我们发现AT丰富序列结合蛋白1(Satb1)可激活QKI转录。综上所述,我们发现,房颤可导致巨噬细胞向促炎型极化,而促炎型巨噬细胞可通过分泌IL-1β,诱导心房肌细胞内QKI表达下调,从而减小QKI与CACNA1CmRNA的结合并降低L型钙离子通道电流。我们的研究揭示了巨噬细胞和心房肌细胞交互作用在房颤发生和发展中的作用,并提供了房颤治疗的新靶点(QKI)。
[Abstract]:Atrial fibrillation (AF) is the most common arrhythmia. Inflammation is thought to play an important role in the occurrence and development of AF. To answer these questions, we did the following: first, we collected and analyzed the right atrial appendage tissue in patients with atrial fibrillation, and we found that, compared with sinus rhythm controls, The infiltration of macrophages in right atrial appendage was increased in patients with atrial fibrillation, and the inflammatory type of iNOS (Arg 1) was the main one. The HL-1 cells of mouse atrial myocytes after rapid pacing were co-cultured with macrophages. On the other hand, the activation of LPS could increase atrial electrical remodeling in mice and dogs, which was characterized by increased incidence of atrial fibrillation. The effective refractory period was shortened and the L-type calcium channel current was decreased, while the removal of proinflammatory macrophages induced by LPS could reduce the atrial electrical remodeling induced by LPS by using phosphonic acid disodium liposome to remove the proinflammatory macrophages in the atrium. The results further confirmed the role of pro-inflammatory macrophages in the pathogenesis of atrial fibrillation. In molecular mechanism, we found that the increase of atrial electrical remodeling induced by pro-inflammatory macrophages was achieved by secreting IL-1 尾. The secretion of IL-1 尾 by macrophages induced a decrease in the expression of RNA binding protein QKI in atrial myocytes. On the other hand, compared with wild-type pro-inflammatory macrophages, IL-1 尾 knockout proinflammatory macrophages were co-cultured with atrial myocytes. It can partially restore the expression of QKI in atrial myocytes, and further confirm the role of IL-1 尾 in the down-regulation of QKI in atrial myocytes induced by pro-inflammatory macrophages. Overexpression of QKI in atrial myocytes increased the binding of QKI to L-type calcium channel protein 伪 1C subunit encoding gene CACNA1C mRNA, and increased CACNA1C expression level and L-type calcium channel current. Finally, in order to study the transcriptional regulation of QKI, we screened transcription factors and found that AT-rich sequence binding protein (AT-rich sequence binding protein 1) can activate QKI transcription. Atrial fibrillation can induce macrophage polarization towards inflammation type, while pro-inflammatory macrophage can induce down-regulation of QKI expression in atrial myocytes by secreting IL-1 尾. Our study revealed the role of macrophage and atrial myocyte interaction in the occurrence and development of atrial fibrillation and provided a new target for the treatment of atrial fibrillation.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R541.75

【相似文献】