Pnmt+心肌细胞对心脏交感神经细胞的反馈调控及机理研究

It is known that the sympathetic nerve regulates the function of the heart in one way through the secreting transmitter. However, so far little is known about their mechanism of communication between the myocytes and the sympathetic cells. We revealed a novel cardiomyocyte subpopulation, named as Pnmt+ cardiomyocytes, which has potential endocrine function. Their anatomical distribution characteristics are similar to that of sympathetic nerve innervation, suggesting that there is mutual communication between them. Based on these findings, we hypothesize that the functional interactions/communications between Pnmt+ cardiomyocytes and sympathetic nerve cells within the heart are crucial for maintaining cardiac-neuronal crosstalk and homeostatic regulation. To test this hypothesis, we propose three series of studies: firstly, we will explore the structural and functional interactions of Pnmt+ cardiomyocytes and sympathetic stellate neurons under physiological and pathological conditions. The studies will be carried out by using in vivo and in vitro models prepared from genetically modified mice. An integrated approach combining with electrophysiology, confocal, optical mapping, cellular and molecular biology and computation from whole organ to cellular and molecular levels will be conducted in the studies. The results obtained from the proposed studies will lead to an in-depth understanding of biological function of Pnmt+ cardiomyocytes and their role in cardiac-neuronal communication and homeostatic regulation.

已知交感神经通过分泌递质单向调控心脏功能,但有关心肌细胞与交感神经细胞间的交流机制研究甚少。我们发现了一类具有潜在内分泌功能的心肌细胞亚群-Pnmt+心肌细胞，其解剖分布特征与交感神经心脏支配相似,提示两者间存在相互交流。我们提出：Pnmt+心肌细胞与交感神经心脏支配末梢形成紧密的结构和功能耦联，通过反馈调控交感神经元来维持心脏-交感神经间的稳态。本课题采用光遗传Pnmt+细胞特异标记和Pnmt敲除等小鼠模型,结合电生理、激光共聚焦、计算模拟、光标测和分子生物学等手段;从细胞到器官多层次研究:确定Pnmt+心肌细胞肾上腺能信号及相关基因谱特征;确定它们与交感神经心脏支配末梢结构和功能的耦联关系;采用细胞条件培养模型明确Pnmt+心肌细胞与交感神经元间的交互作用及信号传递机制。本课题将阐明Pnmt+心肌细胞对心交感神经细胞的反馈调控和紧密物理连接模式,揭示心脏-神经细胞间交流和稳态调控机制。

已知交感神经通过分泌递质单向调控心脏功能,但有关心肌细胞与交感神经细胞间的交流机制研究甚少。本项目采用多种研究方法（包括单细胞测序和空间转录组测序，谱系追踪，分子探针，结合电生理、免疫荧光共聚焦显微成像技术，计算模拟、光遗传光标测、细 胞/分子生物学等多种技术，流式细胞术、膜片钳技术）以小鼠为模型，开展对具有儿茶酚胺分泌潜能的心肌细胞的生物学特性，生理功能及在心肌-交感神经细胞间的交流和心脏功能稳态中的作用的系统性探索性研究。构建小鼠心脏细胞类型单细胞和高分辨时空转录组细胞发育转录谱；阐明Pnmt+心肌细胞和Dbh+心肌细胞的发育轨迹及解剖空间分布和心肌组织结构关系；通过采用系列光遗传小鼠模型结合整体心脏和细胞电生理技术，阐明Pnmt+心肌细胞和Dbh+心肌细胞的电生理特性。阐明Pnmt+心肌细胞和Dbh+心肌细胞的肾上腺能信号特征及其儿茶酚胺摄取、合成，处理功能。超微电镜发现心肌细胞肾上腺能信号超微结构基础；采用病理性肥大心脏模型确定 PNMT/肾上腺素信号系统缺失(PnmtCKO)对心脏功能电生理特征及和交感神经分布特征的影响。这些发现为进一步阐明心脏内分泌功能，心肌细胞与交感神经交流，心-脑调控提供了重要实验基础。

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