Parthenolide regulates DNMT1-mediated methylation of VDR promoter to relieve podocyte damage in mice with diabetic nephropathy

Xinbo Yang,Xiao Yu,Xin Gao,Ni Yang,Meiyun Zhao,Yulei Zhang

doi:10.1590/fst.51221

Abstract

Current evidence showed that parthenolide (PN) has strong anti-inflammatory activity, but its effect on diabetic nephropathy (DN) is still unclear. In this research, high glucose (HG)-induced MPC5 cells were incubated with 5, 10 or 20 μM PN, and we found that PN incubation improved HG-induced MPC5 cells viability and apoptosis, ROS level, LDH activity and the secretion of inflammatory factors (IL-6, TNF-α and IL-1β), and inhibited the expression of DNMT1 protein, and promoted the expression of VDR, p-AKT, nephrin and podocin proteins. Lentivirus-mediated VDR overexpression vector (LV-VDR) transfection had the same effect, and LV-DNMT1 or si-VDR transfection or 100 nM AKT inhibitor MK2206 incubation reversed the effect of PN on cell functions. Research on the mechanism found that PN reduced the level of VDR methylation by reducing the enrichment of DNTM1 in the VDR promoter region under high glucose condition. In vivo, C57BL/6 mice were injected with streptozotocin (STZ) intraperitoneally to construct a DN mouse model, and 5mg/kg PN was administered intraperitoneally every other day. The results showed that PN treatment improved glomerular hypertrophy and renal fibrosis in STZ-induced mice. In general, PN regulated DNTM1-mediated VDR methylation, activated AKT, and alleviated DN.

Highlights

IntroductionAccording to estimates by the World Health Organization, there are approximately 422 million diabetic patients in the world, of which more than 90% have type 2 diabetes (T2DM) (Cho et al, 2018; World Health Organization, 2015)
Diabetic nephropathy (DN) is a serious complication of diabetes
Compared with the control group, we found that the MPC5 cells apoptosis, reactive oxygen species (ROS) level, lactate mouse dehydrogenase (LDH) activity and secretion of cytokine IL-6, tumor necrosis factor (TNF)-α and IL-1β were significantly increased (Figure 1B-H), while the mRNA and protein expression levels of nephrin, podocin and Vitamin D Receptor (VDR) were significantly reduced in high glucose (HG) treatment group (Figure 1I-O)

Summary

Introduction

According to estimates by the World Health Organization, there are approximately 422 million diabetic patients in the world, of which more than 90% have type 2 diabetes (T2DM) (Cho et al, 2018; World Health Organization, 2015). In China, there are approximately 114 million people with diabetes, which greatly harms public health(Zhen et al, 2020). The epigenetic modification of genes plays an important role in the development of DN, among which DNA methylation is the most common (Keating et al, 2017). Related research reported that DNA methylation could participate in the regulation of genes related to the functions of glomeruli and proximal tubular epithelial cells, including filtration, glucose and solute processing (Wanner & Bechtel-Walz, 2017). DNA methylation is mediated by DNA methyltransferase, which inhibits gene expression by recruiting transcription repressors to the promoter region of genes and interfering with transcription factor binding (Jones, 2012)

Methods

Results

Conclusion