ORIGINAL RESEARCH article
Front. Immunol.
Sec. Inflammation
This article is part of the Research TopicCommunity Series in Renal Fibrosis and Renal Transplantation: Vol. IIView all 13 articles
METTL3-driven m6A modification of NLRC5 promotes renal fibrosis in chronic kidney disease through Keap1/Nrf2/ARE signaling pathway
Provisionally accepted
- Hainan General Hospital, Haikou, China
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Background: METTL3-mediated m⁶A RNA methylation has been implicated in renal fibrosis, a central pathological feature of chronic kidney disease (CKD). NLRC5, the largest NLR family member, is a direct m⁶A target of METTL3, but its role in METTL3-driven renal fibrosis remains unclear. Methods: An in vitro renal fibrosis model was established using TGF-β1–stimulated human proximal tubular (HK-2) cells. METTL3-mediated m⁶A modification and stabilization of NLRC5 mRNA were assessed by m⁶A quantification, RNA stability, MeRIP, and RIP assays. Functional impacts on the Keap1/Nrf2/ARE pathway and fibrotic responses were examined using METTL3 inhibition (STM2457, 10 μM), NLRC5 knockdown or overexpression, Keap1 overexpression, and Nrf2 inhibition (ML385, 5 μM). Fibrotic markers, inflammatory cytokines (IL-1β, TNF-α; ELISA), and oxidative stress (ROS/DCF-DA, SOD, MDA) were measured. NLRC5-overexpression effects on the Keap1/Nrf2/ARE pathway were additionally evaluated. In vivo validation employed a unilateral ureteral obstruction (UUO) mouse model, with kidney injury and fibrosis assessed via H&E, Masson’s staining, IHC, ELISA, Western blot, and qRT-PCR. Results: TGF-β1 upregulated METTL3, NLRC5, and global m⁶A levels in HK-2 cells. METTL3 directly bound and stabilized NLRC5 mRNA via m⁶A modification. METTL3 overexpression exacerbated TGF-β1-induced inflammation, oxidative stress, and fibrosis, which were reversed by STM2457. Conversely, METTL3 or NLRC5 inhibition suppressed fibrosis, coinciding with Keap1 downregulation and Nrf2/HO-1/NQO1 upregulation. Keap1 overexpression negated the anti-fibrotic effects of NLRC5 knockdown, while NLRC5 overexpression decreased nuclear Nrf2 and downstream antioxidant targets, confirming NLRC5’s inhibitory role on Keap1/Nrf2 signaling. Nrf2 inhibition (ML385) or NLRC5 overexpression rescued METTL3 knockdown phenotypes. In vivo, METTL3 knockdown attenuated UUO-induced renal injury and fibrosis, activating the Keap1/Nrf2/ARE pathway. Conclusions: METTL3 promotes renal fibrosis by stabilizing NLRC5 mRNA via m⁶A modification, leading to suppression of the protective Keap1/Nrf2/ARE pathway. Targeting the METTL3/NLRC5/Keap1/Nrf2/ARE axis may represent a promising therapeutic strategy for CKD-associated fibrosis.
Keywords: Keap1/Nrf2/ARE pathway, M6A RNA methylation, METTL3, NLRC5, renal fibrosis
Received: 04 Nov 2025; Accepted: 11 Feb 2026.
Copyright: © 2026 Xu, Chen, Zeng, Pan, Wang, Qi, An and Bai. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Yafei Bai
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