Aldehyde Dehydrogenase-2 Alleviates Septic Myocardial Injury by Inhibiting Caspase-11-Mediated Noncanonical Pyroptosis.

PURPOSE: The purpose of this study is to investigate the role of aldehyde dehydrogenase-2 (ALDH2) in septic myocardial injury, focusing on noncanonical pyroptosis.

METHODS: In vivo, C57BL/6J mice were divided into five groups: Sham, cecal ligation and puncture (CLP), CLP + Alda-1 (ALDH2 agonist), Sham + dimethyl sulfoxide (DMSO, solvent control), and CLP + DMSO. Cardiac function and histological/ultrastructural changes were assessed via echocardiography, hematoxylin-eosin (HE) staining, and transmission electron microscopy (TEM). Tumor necrosis factor-α (TNF-α) and noncanonical pyroptosis-related proteins (caspase-11, gasdermin-D [GSDMD], high mobility group box 1 [HMGB1], and receptor for advanced glycation end products [RAGE]) were measured by enzyme-linked immunosorbent assay (ELISA) and western blotting. Coimmunoprecipitation (CO-IP) explored molecular mechanisms. In vitro, H9C2 cells were divided into six groups: Control, lipopolysaccharide (LPS)-treated, ALDH2-green fluorescent protein (GFP), LPS + ALDH2-GFP, GFP, and GFP + LPS. Cell viability, lactate dehydrogenase (LDH) release, creatine kinase isoenzymes (CK-MB), and target protein levels were detected via spectrophotometry, western blotting, and immunofluorescence (IF).

RESULTS: In vivo, Alda-1 significantly attenuated CLP-induced cardiac dysfunction and reduced myocardial histological damage and ultrastructural impairment. In vitro, ALDH2 overexpression lowered LPS-induced H9C2 cell viability, CK-MB, and LDH release. Upregulating ALDH2 significantly reduced caspase-11, HMGB1, and RAGE expression. CO-IP showed ALDH2 interacted with HMGB1, RAGE, and GSDMD.

CONCLUSION: ALDH2 protects the myocardium from septic injury by inhibiting caspase-11-mediated noncanonical pyroptosis, possibly via direct interactions with GSDMD, HMGB1, and RAGE.