SDSU Integrated Regenerative Research Institute and Biology Department, San Diego State University, 5500 Campanile Drive, San Diego, CA, 92182, USA.
Cell Mol Life Sci. 2022 Jul 16;79(8):424. doi: 10.1007/s00018-022-04449-1.
Cardiac fibroblast (CF) population heterogeneity and plasticity present a challenge for categorization of biological and functional properties. Distinct molecular markers and associated signaling pathways provide valuable insight for CF biology and interventional strategies to influence injury response and aging-associated remodeling. Receptor tyrosine kinase c-Kit mediates cell survival, proliferation, migration, and is activated by pathological injury. However, the biological significance of c-Kit within CF population has not been addressed. An inducible reporter mouse detects c-Kit promoter activation with Enhanced Green Fluorescent Protein (EGFP) expression in cardiac cells. Coincidence of EGFP and c-Kit with the DDR2 fibroblast marker was confirmed using flow cytometry and immunohistochemistry. Subsequently, CFs expressing DDR2 with or without c-Kit was isolated and characterized. A subset of DDR2 CFs also express c-Kit with coincidence in ~ 8% of total cardiac interstitial cells (CICs). Aging is associated with decreased number of c-Kit expressing DDR2 CFs, whereas pathological injury induces c-Kit and DDR2 as well as the frequency of coincident expression in CICs. scRNA-Seq profiling reveals the transcriptome of c-Kit expressing CFs as cells with transitional phenotype. Cultured cardiac DDR2 fibroblasts that are c-Kit exhibit morphological and functional characteristics consistent with youthful phenotypes compared to c-Kit cells. Mechanistically, c-Kit expression correlates with signaling implicated in proliferation and cell migration, including phospho-ERK and pro-caspase 3. The phenotype of c-kit on DDR2 CFs correlates with multiple characteristics of 'youthful' cells. To our knowledge, this represents the first evaluation of c-Kit biology within DDR2 CF population and provides a fundamental basis for future studies to influence myocardial biology, response to pathological injury and physiological aging.
心脏成纤维细胞(CF)群体异质性和可塑性对生物学和功能特性的分类提出了挑战。独特的分子标志物和相关信号通路为 CF 生物学提供了有价值的见解,并为干预策略提供了影响损伤反应和与衰老相关重塑的依据。受体酪氨酸激酶 c-Kit 介导细胞存活、增殖、迁移,并通过病理性损伤激活。然而,c-Kit 在 CF 群体中的生物学意义尚未得到解决。诱导型报告小鼠通过增强型绿色荧光蛋白(EGFP)在心脏细胞中的表达来检测 c-Kit 启动子的激活。使用流式细胞术和免疫组织化学证实了 EGFP 和 c-Kit 与 DDR2 成纤维细胞标志物的一致性。随后,分离并鉴定了表达 DDR2 且具有或不具有 c-Kit 的 CF。DDR2 CF 的一个亚群也表达 c-Kit,与总心脏间质细胞(CIC)中的巧合率约为 8%。衰老与表达 c-Kit 的 DDR2 CF 数量减少有关,而病理性损伤则诱导 c-Kit 和 DDR2 以及 CIC 中一致表达的频率增加。scRNA-Seq 分析揭示了表达 c-Kit 的 CF 的转录组是具有过渡表型的细胞。与 c-Kit 细胞相比,培养的具有 DDR2 的心脏成纤维细胞中 c-Kit 的表达表现出与年轻表型一致的形态和功能特征。从机制上讲,c-Kit 的表达与涉及增殖和细胞迁移的信号相关,包括磷酸化-ERK 和原半胱氨酸蛋白酶 3。c-Kit 在 DDR2 CF 上的表型与“年轻”细胞的多种特征相关。据我们所知,这代表了首次对 DDR2 CF 群体中的 c-Kit 生物学进行评估,并为未来研究提供了影响心肌生物学、病理性损伤反应和生理衰老的基本依据。