YTHDF1 alleviates sepsis by upregulating WWP1 to induce NLRP3 ubiquitination and inhibit caspase-1-dependent pyroptosis

Pyroptosis is inflammation-associated caspase-1-dependent programmed cell death, which confers a crucial role in sepsis. The present study intends to investigate the regulatory network and function of the microarray-predicted YTHDF1 in caspase-1-dependent pyroptosis of sepsis. Peripheral blood of patients with sepsis was collected to determine WWP1 and YTHDF1 expression. An in vitro sepsis cell model was induced in RAW264.7 cells using lipopolysaccharide (LPS) and ATP and an in vivo septic mouse model by cecal ligation and perforation (CLP). After gain- and loss-of-function assays in vitro and in vivo, TNF-alpha and IL-1 beta levels and the cleavage of gasdermin-D (GSDMD) were detected by ELISA and Western blot assay, followed by determination of lactate dehydrogenase (LDH) activity. Immunoprecipitation and meRIP assay were performed to detect the ubiquitination of NLRP3 and the m6A modification of WWP1 mRNA. The binding of WWP1 to YTHDF1 was explored using RIP-RT-qPCR and dual luciferase gene reporter assay. It was noted that WWP1 and YTHDF1 were downregulated in clinical sepsis samples, LPS + ATP-treated RAW264.7 cells, and CLP-induced mice. The ubiquitination of NLRP3 was promoted after overexpression of WWP1. WWP1 translation could be promoted by YTHDF1. Then, WWP1 or YTHDF1 overexpression diminished LDH activity, NLRP3 inflammasomes and caspase-1-mediated cleavage of GSDMD in LPS + ATP-induced RAW264.7 cells. Overexpressed YTHDF1 restrained inflammatory response in CLP-induced mice. Collectively, the alleviatory effect of m6A reader protein YTHDF1 may be achieved through promotion of NLRP3 ubiquitination and inhibition of caspase-1-dependent pyroptosis by upregulating WWP1.