Department of Nephrology, The Third XiangYa Hospital Central South University, Changsha, Hunan, P. R. China.
Department of Nephrology, Hunan Provincial People's Hospital (The First Affiliated Hospital of Hunan Normal University), Changsha, Hunan, P. R. China.
FASEB J. 2024 Oct 31;38(20):e70108. doi: 10.1096/fj.202401489R.
Previous studies have shown that paricalcitol (PA) has a protective effect on the kidneys. However, the exact molecular mechanism by which PA affects diabetic nephropathy (DN) progression remains uncertain. PBMCs of patients with DN were isolated, and CYP2J2 and VDR levels were detected by qPCR. Pearson correlation analysis was utilized to detect the relationship between uACR and CYP2J2 and VDR and between CYP2J2 and VDR. The protective effects of PA on DN have been examined by TUNEL, HE staining, ELISA, and Flow cytometry assays in STZ-induced mice. Moreover, THP-1 cells were stimulated with HG/LPS for in vitro studies. ELISA, qPCR, western blot, and Flow cytometry assays were utilized to assess the effects of PA on DN progression by regulating CYP2J2. The interaction between CYP2J2 and VDR was analyzed by CHIP-qPCR and luciferase experiments. CYP2J2 and VDR levels were downregulated and uACR level was upregulated in DN patients. CYP2J2 and VDR were positively correlated in PBMCs. Both CYP2J2 and VDR are inversely correlated with uACR. Moreover, after PA treatment, 11, 12-EET levels increased, inflammatory factor levels decreased, and M2 macrophage polarization was promoted in STZ-induced mice and HG/LPS-triggered THP-1 cells. Depletion of CYP2J2 and VDR decreased 11, 12-EET level, enhanced inflammatory factor levels, and inhibited M2 macrophage polarization, which were reversed by CYP2J2 overexpression in HG/LPS-treated cells. Furthermore, VDR bound to the CYP2J2 promoter and promoted CYP2J2 transcriptional expression. The present work pointed out a new use for PA to inhibit DN progression by increasing EET level, inhibiting inflammatory response, and inducing M2 macrophage polarization via regulating the VDR/CYP2J2 axis.
先前的研究表明，帕立骨化醇（PA）对肾脏具有保护作用。然而，PA 影响糖尿病肾病（DN）进展的确切分子机制仍不确定。分离 DN 患者的 PBMC，通过 qPCR 检测 CYP2J2 和 VDR 水平。采用 Pearson 相关分析检测 uACR 与 CYP2J2 和 VDR 之间以及 CYP2J2 和 VDR 之间的关系。通过 TUNEL、HE 染色、ELISA 和流式细胞术检测 PA 对 STZ 诱导的小鼠 DN 的保护作用。此外，在体外研究中用 HG/LPS 刺激 THP-1 细胞。通过 ELISA、qPCR、western blot 和流式细胞术检测 PA 通过调节 CYP2J2 对 DN 进展的影响。通过 CHIP-qPCR 和荧光素酶实验分析 CYP2J2 和 VDR 之间的相互作用。DN 患者的 CYP2J2 和 VDR 水平下调，uACR 水平上调。PBMC 中 CYP2J2 和 VDR 呈正相关。CYP2J2 和 VDR 与 uACR 均呈负相关。此外，PA 治疗后，11、12-EET 水平增加，炎症因子水平降低，M2 巨噬细胞极化在 STZ 诱导的小鼠和 HG/LPS 触发的 THP-1 细胞中得到促进。CYP2J2 和 VDR 耗竭降低 11、12-EET 水平，增强炎症因子水平，抑制 M2 巨噬细胞极化，在 HG/LPS 处理的细胞中过表达 CYP2J2 可逆转上述作用。此外，VDR 结合 CYP2J2 启动子并促进 CYP2J2 转录表达。本研究指出，PA 通过增加 EET 水平、抑制炎症反应和诱导 M2 巨噬细胞极化来抑制 DN 进展的新用途，通过调节 VDR/CYP2J2 轴。
