Laboratory of Renal Physiology, Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14040-900, SP, Brazil.
Laboratory of Endocrinology, Department of Internal Medicine, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14015-010, SP, Brazil.
Nutrients. 2022 Dec 14;14(24):5316. doi: 10.3390/nu14245316.
Renal endothelial cell (EC) injury and microvascular dysfunction contribute to chronic kidney disease (CKD). In recent years, increasing evidence has suggested that EC undergoes an endothelial-to-mesenchymal transition (EndoMT), which might promote fibrosis. Adriamycin (ADR) induces glomerular endothelial dysfunction, which leads to progressive proteinuria in rodents. The activation of the vitamin D receptor (VDR) plays a crucial role in endothelial function modulation, cell differentiation, and suppression of the expression of fibrotic markers by regulating the production of nitric oxide (NO) by activating the endothelial NO synthase (eNOS) in the kidneys. This study aimed to evaluate the effect of paricalcitol treatment on renal endothelial toxicity in a model of CKD induced by ADR in rats and explore mechanisms involved in EC maintenance by eNOS/NO, angiopoietins (Angs)/endothelium cell-specific receptor tyrosine kinase (Tie-2, also known as TEK) and vascular endothelial growth factor (VEGF)-VEGF receptor 2 (VEGFR2) axis. The results show that paricalcitol attenuated the renal damage ADR-induced with antiproteinuric effects, glomerular and tubular structure, and function protection. Furthermore, activation of the VDR promoted the maintenance of the function and structure of glomerular, cortical, and external medullary endothelial cells by regulating NO production. In addition, it suppressed the expression of the mesenchymal markers in renal tissue through attenuation of (transforming growth factor-beta) TGF-β1/Smad2/3-dependent and downregulated of Ang-2/Tie-2 axis. It regulated the VEGF/VEGFR2 pathway, which was ADR-deregulated. These effects were associated with lower AT1 expression and VDR recovery to renal tissue after paricalcitol treatment. Our results showed a protective role of paricalcitol in the renal microvasculature that could be used as a target for treating the beginning of CKD.
肾内皮细胞 (EC) 损伤和微血管功能障碍导致慢性肾脏病 (CKD)。近年来,越来越多的证据表明,EC 经历内皮-间充质转化 (EndoMT),这可能促进纤维化。阿霉素 (ADR) 诱导肾小球内皮功能障碍,导致啮齿动物进行性蛋白尿。维生素 D 受体 (VDR) 的激活在调节内皮功能、细胞分化和抑制纤维化标志物的表达方面发挥着关键作用,其通过激活肾脏中的内皮型一氧化氮合酶 (eNOS) 来调节一氧化氮 (NO) 的产生。本研究旨在评估帕立骨化醇治疗对 ADR 诱导的 CKD 大鼠模型中肾内皮毒性的影响,并通过 eNOS/NO、血管生成素 (Angs)/内皮细胞特异性受体酪氨酸激酶 (Tie-2,也称为 TEK) 和血管内皮生长因子 (VEGF)-VEGF 受体 2 (VEGFR2) 轴来探索 EC 维持的机制。结果表明,帕立骨化醇通过减少蛋白尿、保护肾小球和肾小管结构和功能来减轻 ADR 诱导的肾损伤。此外,VDR 的激活通过调节 NO 的产生来促进肾小球、皮质和外髓质内皮细胞的功能和结构的维持。此外,它通过抑制 TGF-β1/Smad2/3 依赖性的间质标志物在肾组织中的表达和下调 Ang-2/Tie-2 轴来抑制其表达。它调节了 VEGF/VEGFR2 通路,该通路被 ADR 失调。这些作用与帕立骨化醇治疗后 AT1 表达和 VDR 恢复到肾组织有关。我们的研究结果表明帕立骨化醇在肾微血管中具有保护作用,可作为治疗 CKD 早期的靶点。