FTO-mediated m6A demethylation of pri-miR-3591 alleviates osteoarthritis progression

Abstract

Objectives Increasing evidence have demonstrated the N6-methyladenosine (m6A) plays critical roles in osteoarthritis (OA) progression, but the role of m6A in OA has not been completely illuminated. Herein, we investigated the function and underlying mechanism of m6A demethylase fat mass and obesity-associated protein (FTO) in OA progression. Materials and methods The FTO expression was detected in mice OA cartilage tissues and lipopolysaccharide (LPS)-stimulated chondrocytes. Gain-of-function assays was used to evaluate the role of FTO in OA cartilage injury in vitro and in vivo. The miRNA-sequencing, RNA-binding protein immunoprecipitation (RIP), luciferase reporter assay, and in vitro pri-miRNA processing assays were conducted to confirm that FTO modulated the pri-miR-3591 process in an m6A-dependent manner and then the binding sites of miR-3591-5p with PRKAA2. Results FTO was outstandingly downregulated in LPS-stimulated chondrocytes and OA cartilage tissues. FTO overexpression enhanced the proliferation, suppressed apoptosis, and decreased degradation of extracellular matrix in LPS-induced chondrocytes, whereas FTO knockdown contributed to the opposite effects. In vivo animal experiments showed that FTO overexpression markedly alleviated OA mice cartilage injury. Mechanically, FTO-mediated m6A demethylation of pri-miR-3591 leaded to a maturation block of miR-3591-5p, which relieved the inhibitory effect of miR-3591-5p on PRKAA2 and then promoted the increase of PRKAA2, thereby alleviating OA cartilage damage. Conclusions Our results attested that FTO alleviated the OA cartilage damage by mediating FTO/miR-3591-5p/PRKAA2 axis, which provided fresh insights into the therapeutic strategies for OA.

Obesity-induced downregulation of miR-192 exacerbates lipopolysaccharide-induced acute lung injury by promoting macrophage activation

“…A methylated RNA immunoprecipitation sequencing (MeRIP-seq) study unveiled that FTO knockdown affects the steady-state levels of several miRNAs [ 48 ]. Previous research has also demonstrated that FTO can exert effects in various cancers and inflammatory diseases by influencing miRNA maturation [ 49 , 50 ]. In our findings, overexpression of FTO in MH-S cells resulted in the downregulation of mature miR-192 and pre-miR-192 expression, concomitant with an accumulation of pri-miR-192.…”

ALKBH5‐mediated m6A demethylation of pri‐miR‐199a‐5p exacerbates myocardial ischemia/reperfusion injury by regulating TRAF3‐mediated pyroptosis

“…It was reported that m6A modification, which is mediated by related enzymes, such as METTL3 and FTO, mediates miRNA maturation and expression. [27,28] For instance, FTO enhances m6A demethylation of pri-miR-3591, which impedes miR-3591-5p maturation and inhibits its expression, thereby alleviating osteoarthritis progression. [28] Here, we found m6A modification sites in the pri-miR-199a-5p sequence via the use of the SRAMP website, suggesting that the m6A modification of pri-miR-199a-5p may lead to abnormal miR-199a-5p expression in MI/ RI.…”

“…[27,28] For instance, FTO enhances m6A demethylation of pri-miR-3591, which impedes miR-3591-5p maturation and inhibits its expression, thereby alleviating osteoarthritis progression. [28] Here, we found m6A modification sites in the pri-miR-199a-5p sequence via the use of the SRAMP website, suggesting that the m6A modification of pri-miR-199a-5p may lead to abnormal miR-199a-5p expression in MI/ RI. Thus, we explored whether pri-miR-199a-5p is affected by m6A methylation-related enzymes, thereby affecting miR-199a-5p maturation and expression in MI/RI.…”

Recent advances of m6A methylation in skeletal system disease

“…Increasing evidences have shown that METTL3, WTAP, FTO and ALKBH5 are aberrantly expressed in OA chondrocytes and involved in OA pathogenesis by regulating chondrocyte proliferation, apoptosis, extracellular matrix (ECM) degradation through related signal pathways [ 69 , 72 , 80 , 84 ]. For example, Lin et al have revealed that WTAP-mediated miR-92b-5p/TIMP4 axis plays crucial role in OA development.…”

“…In addition, FTO and ALKBH5 are identified as potential targets to alleviate OA. For example, Liu et al reported that overexpression of FTO inhibited the miR-3591-5p maturation via regulating demethylation of pri-miR-3591, and then downregulated PRKAA2 to alleviate cartilage damage in OA [ 80 ]. Cai and colleagues found that upregulating FTO promoted proliferation, inhibited apoptosis and inflammation in LPS-induced C28/I2 cells through the miR-515-5p/ TLR4/MyD88/NF-κB axis [ 81 ].…”