Wang Xin-Feng, Li Qian, Sun Xia, Zheng Li-Ming, Cheng Shao-Li, Zhu Yan-He
Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China.
Department of Ultrasound, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710004, China.
Curr Med Sci. 2023 Feb;43(1):48-57. doi: 10.1007/s11596-022-2681-6. Epub 2023 Jan 21.
Cardiac fibroblasts (CFs) proliferation and extracellular matrix deposition are important features of cardiac fibrosis. Various studies have indicated that vitamin D displays an anti-fibrotic property in chronic heart diseases. This study explored the role of vitamin D in the growth of CFs via an integrin signaling pathway.
MTT and 5-ethynyl-2'-deoxyuridine assays were performed to determine cell viability. Western blotting was performed to detect the expression of proliferating cell nuclear antigen (PCNA) and integrin signaling pathway. The fibronectin was observed by ELISA. Immunohistochemical staining was employed to evaluate the expression of integrin β3.
The PCNA expression in the CFs was enhanced after isoproterenol (ISO) stimulation accompanied by an elevated expression of integrin beta-3 (β3). The blockade of the integrin β3 with a specific integrin β3 antibody reduced the PCNA expression induced by the ISO. Decreasing the integrin β3 by siRNA reduced the ISO-triggered phosphorylation of FAK and Akt. Both the FAK inhibitor and Akt inhibitor suppressed the PCNA expression induced by the ISO in the CFs. Calcitriol (CAL), an active form of vitamin D, attenuated the ISO-induced CFs proliferation by downregulating the integrin β3 expression, and phosphorylation of FAK and Akt. Moreover, CAL reduced the increased levels of fibronectin and hydroxyproline in the CFs culture medium triggered by the ISO. The administration of calcitriol decreased the integrin β3 expression in the ISO-induced myocardial injury model.
These findings revealed a novel role for CAL in suppressing the CFs growth by the downregulation of the integrin β3/FAK/Akt pathway.
心脏成纤维细胞（CFs）增殖和细胞外基质沉积是心脏纤维化的重要特征。多项研究表明，维生素D在慢性心脏病中具有抗纤维化特性。本研究通过整合素信号通路探讨维生素D在CFs生长中的作用。
采用MTT和5-乙炔基-2'-脱氧尿苷试验测定细胞活力。进行蛋白质免疫印迹法检测增殖细胞核抗原（PCNA）和整合素信号通路的表达。通过酶联免疫吸附测定法观察纤连蛋白。采用免疫组织化学染色评估整合素β3的表达。
异丙肾上腺素（ISO）刺激后，CFs中PCNA表达增强，同时整合素β3（β3）表达升高。用特异性整合素β3抗体阻断整合素β3可降低ISO诱导的PCNA表达。通过小干扰RNA降低整合素β3可减少ISO触发的黏着斑激酶（FAK）和蛋白激酶B（Akt）磷酸化。FAK抑制剂和Akt抑制剂均抑制了ISO诱导的CFs中PCNA的表达。骨化三醇（CAL），维生素D的一种活性形式，通过下调整合素β3表达以及FAK和Akt的磷酸化来减弱ISO诱导的CFs增殖。此外，CAL降低了ISO触发的CFs培养基中纤连蛋白和羟脯氨酸水平的升高。在ISO诱导的心肌损伤模型中给予骨化三醇可降低整合素β3的表达。
这些发现揭示了CAL通过下调整合素β3/FAK/Akt通路抑制CFs生长的新作用。
