m6A methyltransferase METTL3 programs CD4+ T-cell activation and effector T-cell differentiation in systemic lupus erythematosus

Abstract

Background Systemic lupus erythematosus (SLE) is an autoimmune disorder in which excessive CD4+ T-cell activation and imbalanced effector T-cell differentiation play critical roles. Recent studies have implied a potential association between posttranscriptional N6-methyladenosine (m6A) modification and CD4+ T-cell-mediated humoral immunity. However, how this biological process contributes to lupus is not well understood. In this work, we investigated the role of the m6A methyltransferase like 3 (METTL3) in CD4+ T-cell activation, differentiation, and SLE pathogenesis both in vitro and in vivo. Methods The expression of METTL3 was knocked down and METTL3 enzyme activity was inhibited using siRNA and catalytic inhibitor, respectively. In vivo evaluation of METTL3 inhibition on CD4+ T-cell activation, effector T-cell differentiation, and SLE pathogenesis was achieved using a sheep red blood cell (SRBC)-immunized mouse model and a chronic graft versus host disease (cGVHD) mouse model. RNA-seq was performed to identify pathways and gene signatures targeted by METTL3. m6A RNA-immunoprecipitation qPCR was applied to confirm the m6A modification of METTL3 targets. Results METTL3 was defective in the CD4+ T cells of SLE patients. METTL3 expression varied following CD4+ T-cell activation and effector T-cell differentiation in vitro. Pharmacological inhibition of METTL3 promoted the activation of CD4+ T cells and influenced the differentiation of effector T cells, predominantly Treg cells, in vivo. Moreover, METTL3 inhibition increased antibody production and aggravated the lupus-like phenotype in cGVHD mice. Further investigation revealed that catalytic inhibition of METTL3 reduced Foxp3 expression by enhancing Foxp3 mRNA decay in a m6A-dependent manner, hence suppressing Treg cell differentiation. Conclusion In summary, our findings demonstrated that METTL3 was required for stabilizing Foxp3 mRNA via m6A modification to maintain the Treg differentiation program. METTL3 inhibition contributed to the pathogenesis of SLE by participating in the activation of CD4+ T cells and imbalance of effector T-cell differentiation, which could serve as a potential target for therapeutic intervention in SLE.

Identification of m6A-Related Biomarkers in Systemic Lupus Erythematosus: A Bioinformation-Based Analysis

“…7,8 Recent studies on MMP9 and ischemic stroke has provided valuable insights into the complex interplay between MMP9 and various aspects of ischemic stroke, including blood brain barrier (BBB) dysfunction, cognitive impairment, therapeutic targets and pathophysiological changes. [9][10][11] The SNPs characteristics of MMP9 and Ischemic stroke were considered robust instrumental variables (Supplementary Table S2). Figures 10A and C illustrate the individual genetic variations' causal effects on SLE.…”

“…[5][6][7][8] METTL3 plays a key role in regulating the activation and differentiation of CD4 + T cells, and its downregulation in SLE patients may impact T cell-mediated immune responses. 9 Conversely, the upregulation of circGARS, acting as a sponge for miR-19a, affects the expression of the m6A reader YTHDF2 and A20, consequently modulating the NF-κB pathway, potentially exacerbating SLE pathology. 10 Additionally, the differential expression of m6A-modified long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) in SLE patients suggests their potential roles in the disease, possibly serving as new therapeutic targets for SLE.…”

The role of RNA methylation in tumor immunity and its potential in immunotherapy

“…Researchers have demonstrated that inhibiting METTL3 facilitates the activation of CD4 + T cells while suppressing the differentiation of effector T cells, particularly Treg cells, by reducing the expression of Foxp3 in a m6A-dependent manner [ 247 ]. Inhibition of METTL3 reduces m6A methylation levels, promotes cell apoptosis, hinders effector T cell differentiation, and inhibits allogeneic CD4 + T cell responses [ 24 ].…”