METTL14 aggravates podocyte injury and glomerulopathy progression through N6-methyladenosine-dependent downregulating of Sirt1

Zhihui Lu,Jiaming Zhu,Nana Song,Jiachang Hu,Hong Liu,Xiaoqiang Ding,Yan Dai,Yichun Ning,Yi Fang,Yiran Liang,Jianzhou Zou,Jie Teng,Jing Chen

doi:10.1038/s41419-021-04156-y

Abstract

Podocytes are known to play a determining role in the progression of proteinuric kidney disease. N6-methyladenosine (m6A), as the most abundant chemical modification in eukaryotic mRNA, has been reported to participate in various pathological processes. However, its role in podocyte injury remains unclear. In this study, we observed the elevated m6A RNA levels and the most upregulated METTL14 expression in kidneys of mice with adriamycin (ADR) and diabetic nephropathy. METTL14 was also evidently increased in renal biopsy samples from patients with focal segmental glomerulosclerosis (FSGS) and diabetic nephropathy and in cultured human podocytes with ADR or advanced glycation end product (AGE) treatment in vitro. Functionally, we generated mice with podocyte-specific METTL14 deletion, and identified METTL14 knockout in podocytes improved glomerular function and alleviated podocyte injury, characterized by activation of autophagy and inhibition of apoptosis and inflammation, in mice with ADR nephropathy. Similar to the results in vivo, knockdown of METTL14 facilitated autophagy and alleviated apoptosis and inflammation in podocytes under ADR or AGE condition in vitro. Mechanically, we identified METTL14 knockdown upregulated the level of Sirt1, a well-known protective deacetylase in proteinuric kidney diseases, in podocytes with ADR or AGE treatment. The results of MeRIP-qPCR and dual-luciferase reporter assay indicated METTL14 promoted Sirt1 mRNA m6A modification and degradation in injured podocytes. Our findings suggest METTL14-dependent RNA m6A modification contributes to podocyte injury through posttranscriptional regulation of Sirt1 mRNA, which provide a potential approach for the diagnosis and treatment of podocytopathies.

Highlights

The terminally differentiated podocytes, which are indispensable components of glomerular filtration barrier, play a critical role in the pathomechanism of proteinuric kidney disease, such as focal segmental glomerulosclerosis (FSGS) and diabetic nephropathy (DN) [1, 2]
The sections were stained with uranyl acetate and RESULTS The increased methyltransferase-like 14 (METTL14)-mediated RNA m6A modification in ADR and db/db mice To investigate the alteration of RNA m6A modification in proteinuric kidney disease, we quantified the levels of m6A methylated RNA extracted from the renal cortex of ADR-treated mice, diabetic db/db mice and their corresponding controls using colorimetric ELISA assay
We extracted the glomeruli of mice with the two proteinuric kidney disease, and found the m6A levels of total RNA were increased in isolated glomeruli of ADR-treated mice and db/db mice compared with their normal controls (Supplementary Fig. 1A, B)

Summary

Introduction

The terminally differentiated podocytes, which are indispensable components of glomerular filtration barrier, play a critical role in the pathomechanism of proteinuric kidney disease, such as focal segmental glomerulosclerosis (FSGS) and diabetic nephropathy (DN) [1, 2]. The lack of effective interventions on preventing podocyte injury demands a better understanding of the key and universal molecules involved in various podocytopathies, which may provide potential diagnostic and therapeutic measures for patients with proteinuric kidney disease [4]. Recent studies demonstrate that dysregulated RNA m6A modification is involved in various pathological processes, such as abnormal cell differentiation and pluripotency [12], brain diseases [13] and tumorigenesis [14, 15]. The role of RNA m6A methylation and its regulatory mechanism remain unclear in podocytopathies

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Results

Conclusion