METTL5 deficiency impairs osteogenesis through OSER1-dependent antioxidant regulation
Kexin Lei, Qi Yin, Qiwen Li, Qian Wang, Zhong Zhang, Fei Xue, Ruoshi Xu, Xinyi Zhou, Lin Peng, Shoichiro Kokabu, Shuibin Lin, Quan Yuan
Kexin Lei, Qi Yin, Qiwen Li, Qian Wang, Zhong Zhang, Fei Xue, Ruoshi Xu, Xinyi Zhou, Lin Peng, Shoichiro Kokabu, Shuibin Lin, Quan Yuan
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Research Article Bone biology Cell biology

METTL5 deficiency impairs osteogenesis through OSER1-dependent antioxidant regulation

Abstract

Methyltransferase-like 5 (METTL5) is a methyltransferase responsible for rRNA N6-methyladenosine (m6A) modification, mutations in which are associated with skeletal abnormalities and cognitive deficits. Despite METTL5’s clinical relevance, the molecular mechanisms underlying METTL5-related genetic disorders remain poorly understood. In this study, we demonstrated that Mettl5 KO led to reduced bone mass and smaller body size in mice and impaired the osteogenic differentiation of mesenchymal stem cells. Mechanistically, Mettl5 deficiency decreased the translation efficiency of oxidative stress–responsive serine-rich protein 1 mRNA, downregulated the expression of key antioxidant genes, and diminished antioxidant capacity. Importantly, administration of the antioxidant N-acetylcysteine (NAC) partially rescued skeletal defects in Mettl5-KO mice. These findings reveal a critical role for METTL5 in antioxidant defense and suggest that NAC supplementation may represent a promising therapeutic strategy for METTL5-related disorders.

Authors

Kexin Lei, Qi Yin, Qiwen Li, Qian Wang, Zhong Zhang, Fei Xue, Ruoshi Xu, Xinyi Zhou, Lin Peng, Shoichiro Kokabu, Shuibin Lin, Quan Yuan

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Figure 5

Mettl5 deletion leads to reduced antioxidant capacity in osteogenic lineage cells.

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Mettl5 deletion leads to reduced antioxidant capacity in osteogenic lin...
(A) GO enrichment analysis of downregulated genes in MSCs from Mettl5-KO mice after osteogenic induction. (B) Heatmap showing differentially expressed osteogenic and antioxidant-related genes identified by RNA-seq. (C) Representative Western blot images showing protein levels of selected antioxidant-related proteins in WT and Mettl5-KO MSCs. n = 3. (D) Representative immunofluorescence images showing CAT signal intensity and corresponding quantification in femurs from WT and Mettl5-KO mice. Scale bar: 100 μm. n = 3. (E) Representative immunofluorescence images showing GSTP1 signal intensity and corresponding quantification in femurs from WT and Mettl5-KO mice. Scale bar: 100 μm. n = 3. (F) KEGG pathway analysis of downregulated metabolites in the plasma of Mettl5-KO mice. (G) Representative fluorescent staining using a glutathione probe and corresponding quantification of glutathione signal in WT and Mettl5-KO MSCs. Scale bar: 40 μm. n = 5. (H) Flow cytometry analysis and quantification of glutathione levels in WT and Mettl5-KO MSCs. n = 4. (I and J) Representative images of Calcein-AM and PI staining in si-Control and si-Mettl5 MC3T3-E1 cells treated with different concentrations of H2O2, with corresponding quantification of live cell ratios at each concentration. Scale bar: 100 μm. n = 3. Data are expressed as mean ± SD; P values were determined by 2-tailed Student’s t test.