MicroRNA-204-GSDMD interaction regulates pyroptosis of fibroblast-like synoviocytes in ankylosing spondylitis.

Ankylosing spondylitis (AS) is a disease characterized by inflammation of the sacroiliac joint and the attachment point of the spine. This study aimed to investigate the effect of microRNA (miR)-204-targeted GSDMD on fibroblast-like synoviocytes (FLSs) in AS. miR-204, GSDMD, pyrolysis-related genes (Caspase-1, Caspase-11 and NLRP3) in synovial tissues from AS patients were tested by RT-qPCR. Online website prediction and dual luciferase reporter gene assay were conducted to verify the binding relationship between miR-204 and GSDMD. FLSs were isolated from AS patients and transfected with miR-204- or GSDMD-related oligonucleotides, siRNA and plasmids to explore their roles in pyroptosis of FLSs. Intracellular [Ca2+] was detected by laser scanning confocal microscopy, reactive oxygen species (ROS) by DCFH-DA and pyrolysis by AO/EB staining and flow cytometry. Decreased miR-204 and elevated GSDMD were found in synovial tissue of patients with AS. miR-204 could directly target GSDMD and inhibit GSDMD protein expression. FLSs treated with miR-204 mimic inhibited the pyroptosis rate and Caspase-1/PI double-positive cells and reduced [Ca2+], ROS, NLRP3, Caspase-1 and Caspase-11 levels in FLSs. Up-regulating GSDMD blocked the effect of miR-204 overexpression on FLSs. Altogether, up-regulated miR-204 suppresses pyroptosis of FLSs in AS via suppressing GSDMD, which may help us to understand the mechanism of AS deeply.