METTL3 Attenuates LPS-Induced Inflammatory Response in Macrophages via NF-κB Signaling Pathway

Abstract

Methyltransferase-like 3 (METTL3), an RNA N6-methyladenosine (m6A) methyltransferase, is essential for the m6A mRNA modification. As a key enzyme of m6A methylation modification, METTL3 has been implicated in immune and inflammation regulation. However, little is known of the role and underlying mechanism of METTL3 in rheumatoid arthritis (RA). The aim of the present study is to elucidate the function and potential mechanism of METTL3 in RA pathogenesis. We used quantitative real-time polymerase chain reaction to detect the expression of METTL3 in RA patients and controls as well as the macrophage cell line. CCK-8 was used for cell proliferation assay. Enzyme-linked immunosorbent assay (ELISA) was adopted to estimate the generation of IL-6 and TNF-α in macrophages. Western blot and immunofluorescence were applied to evaluate the activation of NF-κB in macrophages. The expression of METTL3 was significantly elevated in patients with RA. It was positively associated with CRP and ESR, two common markers for RA disease activity. Besides, LPS could enhance the expression and biological activity of METTL3 in macrophages, while overexpression of METTL3 significantly attenuated the inflammatory response induced by LPS in macrophages. Moreover, the effect of METTL3 on LPS-induced inflammation in macrophages was dependent on NF-κB. This study firstly demonstrates the critical role of METTL3 in RA, which provides novel insights into recognizing the pathogenesis of RA and a promising biomarker for RA.

Decreased ALKBH5, FTO, and YTHDF2 in Peripheral Blood Are as Risk Factors for Rheumatoid Arthritis

“…The reason of downregulated m6A regulators in RA compared with CON may be the environmental, infectious, and genetic factor, as well as some RA risk factors (unbalance of adaptive and innate immune). Recently, Wang and colleagues have investigated the expression of METTL3, FTO, ALKBH5, METTL14, and YTHDF2 in peripheral blood mononuclear cell from RA patients and reported conflicting results in which only METTL3 was obviously upregulated in RA [27]. The reasons for these outcomes are probably due to differences in cell type and the disease duration.…”

Multifaceted Functions and Novel Insight Into the Regulatory Role of RNA N6-Methyladenosine Modification in Musculoskeletal Disorders

“…An integrative study performed by Wang J. et al (2019) analyzing the transcriptome-wide m 6 A methylome enriched by chemotherapy in OS stem cells (OSCs) has revealed that several m 6 A-related enzymes (METTL3, METTL14, FTO, ALKBH5) were altered in OS cells compared with noncancerous counterparts. The aberrantly expressed genes were associated with pluripotency regulation of the OSCs ( Wang J. et al, 2019 ).…”

“…An integrative study performed by Wang J. et al (2019) analyzing the transcriptome-wide m 6 A methylome enriched by chemotherapy in OS stem cells (OSCs) has revealed that several m 6 A-related enzymes (METTL3, METTL14, FTO, ALKBH5) were altered in OS cells compared with noncancerous counterparts. The aberrantly expressed genes were associated with pluripotency regulation of the OSCs ( Wang J. et al, 2019 ). Further, it has been shown that lncRNA plasmacytoma variant translocation 1 (PVT1) transcript was upregulated because of m 6 A methylation decrease mediated by ALKBH5, which reduced the binding of reader protein YTHDF2 in PVT1, subsequently lessening the degradation of PVT1 and promoting tumorigenesis of OS ( Chen et al, 2020 ).…”

“…Specifically, METTL3 inhibited the generation of IL-6 and TNF-α in macrophages via restraining the phosphorylation of NF-κB. Therefore, METTL3 may serve as a potential biomarker for diagnosis of RA ( Wang J. et al, 2019 ). However, because of the limitation of current studies, we can only hypothesize that m 6 A can decelerate the progression of RA via regulating the inflammatory response of immune cells; studies are still needed to provide more evidences.…”

Transcriptome-wide assessment of the m6A methylome of intestinal porcine epithelial cells treated with deoxynivalenol

“…Among these, METTL3 showed the most obvious difference between normal cells and DON-treated cells. METTL3, as a key enzyme of m 6 A methylation modi cation, can attenuate LPS induced in ammatory response in macrophages through NF-κB signaling pathway [48]. METTL3 knockdown inhibits osteoblast differentiation and activates the in ammatory response by regulating MAPK signaling in LPS-induced in ammation [49].…”