METTL23 mutation alters histone H3R17 methylation in normal-tension glaucoma
Yang Pan, … , Toru Nakazawa, Takeshi Iwata
Yang Pan, … , Toru Nakazawa, Takeshi Iwata
Published September 13, 2022
Citation Information: J Clin Invest. 2022;132(21):e153589. https://doi.org/10.1172/JCI153589.
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Research Article Ophthalmology

METTL23 mutation alters histone H3R17 methylation in normal-tension glaucoma

Abstract

Normal-tension glaucoma (NTG) is a heterogeneous disease characterized by retinal ganglion cell (RGC) death leading to cupping of the optic nerve head and visual field loss at normal intraocular pressure (IOP). The pathogenesis of NTG remains unclear. Here, we describe a single nucleotide mutation in exon 2 of the methyltransferase-like 23 (METTL23) gene identified in 3 generations of a Japanese family with NTG. This mutation caused METTL23 mRNA aberrant splicing, which abolished normal protein production and altered subcellular localization. Mettl23–knock-in (Mettl23+/G and Mettl23G/G) and -knockout (Mettl23+/– and Mettl23–/–) mice developed a glaucoma phenotype without elevated IOP. METTL23 is a histone arginine methyltransferase expressed in murine and macaque RGCs. However, the novel mutation reduced METTL23 expression in RGCs of Mettl23G/G mice, which recapitulated both clinical and biological phenotypes. Moreover, our findings demonstrated that METTL23 catalyzed the dimethylation of H3R17 in the retina and was required for the transcription of pS2, an estrogen receptor α target gene that was critical for RGC homeostasis through the negative regulation of NF-κB–mediated TNF-α and IL-1β feedback. These findings suggest an etiologic role of METTL23 in NTG with tissue-specific pathology.

Authors

Yang Pan, Akiko Suga, Itaru Kimura, Chojiro Kimura, Yuriko Minegishi, Mao Nakayama, Kazutoshi Yoshitake, Daisuke Iejima, Naoko Minematsu, Megumi Yamamoto, Fumihiko Mabuchi, Mitsuko Takamoto, Yukihiro Shiga, Makoto Araie, Kenji Kashiwagi, Makoto Aihara, Toru Nakazawa, Takeshi Iwata

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Figure 4

The METTL23 c.A83G mutation leads to aberrant expression and trafficking in vitro.

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The METTL23 c.A83G mutation leads to aberrant expression and trafficking...
(A) METTL23 expression was reduced by the c.A83G mutation. Expression of full-length METTL23, splicing 1 (skip exon 2) and splicing 2 (skip exons 2 and 3) with the C-terminal FLAG-tag in HEK293T, COS-7, and 661W cells was determined by WB. (B) Quantification of METTL23 expression. Data are representative of 3 independent experiments. (C and D) Localization of METTL23 and different splicing products with the C-terminal FLAG-tag in transfected COS-7 (C) and 661W (D) cells by immunofluorescence. METTL23 was labeled with anti-METTL23 (green) and anti-FLAG (red) antibodies. Nuclei were stained with DAPI (blue). Scale bars: 10 μm. (E) 2.5D expression pattern of variant METTL23 in COS-7 and 661W cells. (F) Medium optical density (MOD) statistical results for METTL23 in transfected COS-7 and 661W cells. Results are representative of 4–11 independent experiments. All data are presented as the mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001, by 1-way ANOVA followed by Tukey’s multiple-comparison test.