Department of Endocrinology, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, China.
Nanjing Kingmed Center for Clinical Laboratory Co., Ltd., 11 Yaogu Avenue, Nanjing, Jiangsu, China.
Cell Commun Signal. 2024 Oct 25;22(1):519. doi: 10.1186/s12964-024-01895-1.
Podocyte injury causes proteinuria and accelerates glomerular sclerosis during diabetic kidney disease (DKD). Disruptor of telomeric silencing 1-like (DOT1L), an evolutionarily conserved histone methyltransferase, has been reported in preventing kidney fibrosis in chronic kidney disease models. However, whether DOT1L exerts beneficial effects in diabetes induced podocyte injury and the underlying molecular mechanisms need further exploration.
The expression of DOT1L was confirmed by Western blotting in MPC-5 cells and cortex of kidney from db/db mice, as well as immunofluorescence staining in human renal biopsy samples. The effect of DOT1L on podocyte injury was obtained using MPC-5 cells and db/db mice. The potential target genes regulated by DOT1L was measured by RNA-sequencing. Then, a series of molecular biological experiments was performed to investigate the regulation of PLCL1 by DOT1L in MCP-5 cells and db/db mice. Lipid accumulation was assessed by UPLC-MS/MS analysis and Oil Red O staining.
DOT1L expression was significantly declined in high glucose (HG)-treated MPC-5 cells, podocyte regions of kidney tissues from db/db mice and human renal biopsy samples. Subsequent investigations revealed that upregulation of DOT1L ameliorated HG-induced cell apoptosis in MPC-5 cells as well as primary podocytes. Furthermore, podocyte-specific DOT1L overexpression inhibited diabetic podocyte injury in db/db mice. Mechanistically, we revealed that DOT1L upregulated phospholipase C-like 1 (PLCL1) expression by mediating H3K79me2 at its promoter and PLCL1 silencing suppressed the protective role of DOT1L on podocyte injury. Moreover, DOT1L improved diabetes induced abnormal fatty acid metabolism in podocytes and PLCL1 knockdown reversed its protective effects.
Taken together, our results indicate that DOT1L protects podocyte injury via PLCL1-mediated fatty acid metabolism and provides new insights into the therapeutic target of DKD.
足细胞损伤导致蛋白尿，并在糖尿病肾病（DKD）期间加速肾小球硬化。已报道端粒沉默 1 样蛋白（DOT1L），一种进化上保守的组蛋白甲基转移酶，可在慢性肾脏病模型中预防肾纤维化。然而，DOT1L 是否在糖尿病诱导的足细胞损伤中发挥有益作用，以及潜在的分子机制仍需进一步探索。
通过 Western blot 在 MPC-5 细胞和 db/db 小鼠肾脏皮质中证实了 DOT1L 的表达，并通过免疫荧光染色在人肾活检样本中进行了验证。通过 MPC-5 细胞和 db/db 小鼠获得了 DOT1L 对足细胞损伤的影响。通过 RNA 测序测量了由 DOT1L 调节的潜在靶基因。然后，进行了一系列分子生物学实验，以研究 DOT1L 在 MCP-5 细胞和 db/db 小鼠中对 PLCL1 的调节。通过 UPLC-MS/MS 分析和油红 O 染色评估脂质积累。
在高糖（HG）处理的 MPC-5 细胞、db/db 小鼠肾脏组织的足细胞区域和人肾活检样本中，DOT1L 的表达明显下降。随后的研究表明，上调 DOT1L 可改善 HG 诱导的 MPC-5 细胞和原代足细胞中的细胞凋亡。此外，足细胞特异性 DOT1L 过表达抑制了 db/db 小鼠的糖尿病足细胞损伤。在机制上，我们发现 DOT1L 通过调节其启动子处的 H3K79me2 而上调磷脂酶 C 样 1（PLCL1）的表达，PLCL1 沉默抑制了 DOT1L 对足细胞损伤的保护作用。此外，DOT1L 改善了糖尿病诱导的足细胞中异常脂肪酸代谢，而 PLCL1 敲低则逆转了其保护作用。
综上所述，我们的研究结果表明，DOT1L 通过 PLCL1 介导的脂肪酸代谢来保护足细胞损伤，并为 DKD 的治疗靶点提供了新的见解。
