METTL3-dependent N6-methyladenosine RNA modification promotes diabetes-associated periodontitis via mediating macrophage pyroptosis

Patients with diabetes are twice as likely to suffer from periodontitis (PD) than those without diabetes, and diabetes-associated PD is distinguished by increased inflammation and aggravated tissue damage. However, the underlying mechanisms remain largely unknown, leading to undetermined effective treatment for diabetes-associated PD. One of the most significant epigenetic alterations, N 6 -methyladenosine (m 6 A) modifications are implicated in a number of developmental and pathological processes. Here, we found that Methyltransferase-like 3 (METTL3) expression was upregulated in diabetes-associated PD mice and macrophages under Porphyromonas gingivalis and high glucose stimulation. Functionally, m 6 A RNA hypermethylation and pyroptosis were eliminated by METTL3 knockdown, but more significant alterations were brought about by METTL3 overexpression. Moreover, using methylation RNA immunoprecipitation, nod-like receptor family pyrin domain-containing 3 (NLRP3) was found to be a target of METTL3. Mechanistically, METTL3 increased m 6 A methylation level of NLRP3 and further affects macrophage pyroptosis. Binding of insulin-like growth factor 2 binding protein 3 (IGF2BP3) to the m 6 A-modified domains of NLRP3 was necessary for its stability. Lastly, the silencing of METTL3 mediated by adeno-associated virus 9 (AAV9) ameliorated periodental inflammation and alveolar bone loss in diabetes-associated PD mice. Collectively, we have shown that METTL3 induced m 6 A alterations of NLRP3 and enhanced its stability through pathways depended on IGF2BP3, thereby inducing macrophage pyroptosis in diabetes-associated PD progression, providing evidence that the METTL3/NLRP3 axis is a new and promising target for treating diabetes-associated PD.