Kisling Andrew, Byrne Shannon, Parekh Rohan U, Melit-Thomas Deepthy, de Castro Brás Lisandra E, Lust Robert M, Clemens Stefan, Sriramula Srinivas, Katwa Laxmansa C
Department of Physiology, Brody School of Medicine at East Carolina University, Greenville, NC, United States.
Department of Pharmacology and Toxicology, Brody School of Medicine at East Carolina University, Greenville, NC, United States.
Front Cardiovasc Med. 2021 Oct 11;8:732282. doi: 10.3389/fcvm.2021.732282. eCollection 2021.
Evidence suggests the existence of an intracardiac dopaminergic system that plays a pivotal role in regulating cardiac function and fibrosis through G-protein coupled receptors, particularly mediated by dopamine receptor 3 (D3R). However, the expression of dopamine receptors in cardiac tissue and their role in cardiac fibroblast function is unclear. In this brief report, first we determined expression of D1R and D3R both in left ventricle (LV) tissue and fibroblasts. Then, we explored the role of D3R in the proliferation and migration of fibroblast cell cultures using both genetic and pharmaceutical approaches; specifically, we compared cardiac fibroblasts isolated from LV of wild type (WT) and D3R knockout (D3KO) mice in response to D3R-specific pharmacological agents. Finally, we determined if loss of D3R function could significantly alter LV fibroblast expression of collagen types I (Col1a1) and III (Col3a1). Cardiac fibroblast proliferation was attenuated in D3KO cells, mimicking the behavior of WT cardiac fibroblasts treated with D3R antagonist. In response to scratch injury, WT cardiac fibroblasts treated with the D3R agonist, pramipexole, displayed enhanced migration compared to control WT and D3KO cells. Loss of function in D3R resulted in attenuation of both proliferation and migration in response to scratch injury, and significantly increased the expression of Col3a1 in LV fibroblasts. These findings suggest that D3R may mediate cardiac fibroblast function during the wound healing response. To our knowledge this is the first report of D3R's expression and functional significance directly in mouse cardiac fibroblasts.
有证据表明存在一种心内多巴胺能系统，该系统通过G蛋白偶联受体在调节心脏功能和纤维化中起关键作用，特别是由多巴胺受体3（D3R）介导。然而，心脏组织中多巴胺受体的表达及其在心脏成纤维细胞功能中的作用尚不清楚。在本简要报告中，首先我们确定了D1R和D3R在左心室（LV）组织和成纤维细胞中的表达。然后，我们使用基因和药物方法探讨了D3R在成纤维细胞培养物增殖和迁移中的作用；具体而言，我们比较了从野生型（WT）和D3R基因敲除（D3KO）小鼠的LV中分离的心脏成纤维细胞对D3R特异性药理剂的反应。最后，我们确定D3R功能丧失是否会显著改变LV成纤维细胞中I型（Col1a1）和III型（Col3a1）胶原蛋白的表达。D3KO细胞中的心脏成纤维细胞增殖减弱，类似于用D3R拮抗剂处理的WT心脏成纤维细胞的行为。在划痕损伤后，用D3R激动剂普拉克索处理的WT心脏成纤维细胞与对照WT和D3KO细胞相比，迁移增强。D3R功能丧失导致划痕损伤后增殖和迁移均减弱，并显著增加LV成纤维细胞中Col3a1的表达。这些发现表明，D3R可能在伤口愈合反应中调节心脏成纤维细胞功能。据我们所知，这是关于D3R在小鼠心脏成纤维细胞中直接表达及其功能意义的首次报告。
