ALPK1 promotes cardiomyocyte hypertrophy by activating NF-κB/NLRP3 inflammasome-mediated pyroptosis.

BACKGROUND

Cardiac hypertrophy is a leading risk factor for cardiovascular morbidity and mortality. Alpha-protein kinase 1 (ALPK1) is a novel essential player in innate immunity and inflammation. Therapeutic agents targeting ALPK1 have successively entered clinical trials and become research hotspots. However, the role of ALPK1 on cardiac hypertrophy remains unknown.

METHODS

In the present study, transverse aortic constriction (TAC) was used to establish in vivo models of cardiac hypertrophy. Neonatal mouse cardiomyocytes (NMCMs) and AC16 human cardiomyocytes treated with angiotensin Ⅱ (Ang Ⅱ) were performed to mimic in vitro models of cardiac hypertrophy. ALPK1 gene expression was knocked down by small interfering RNAs (siRNAs) and overexpressed by transfection with plasmid, respectively.

RESULTS

ALPK1 was significantly upregulated in cardiac hypertrophy. ALPK1 knockdown effectively suppressed Ang Ⅱ-induced upregulated hypertrophic markers, enlarged cell surface area, decreased cell viability, increased lactate dehydrogenase release, enhanced caspase-1 activity, elevated positive pyroptotic cells, as well as the upregulation of p-NF-κB p65, NLRP3 inflammasome and pyroptosis markers in both NMCMs and AC16 cells. ALPK1 knockdown markedly suppressed the increased secretion of IL-1β and IL-18 induced by Ang Ⅱ in NMCMs. Consistently, ALPK1 over-expression significantly increased the expression of hypertrophic markers, enhanced the cell surface area, elevated the number of pyroptotic cells, upregulated the protein expression of NLRP3 inflammasome and pyroptosis markers, increased the secretion of IL-1β and IL-18, which were successfully reversed by the addition of MCC950, a selective NLRP3 inflammasome inhibitor. However, MCC950 treatment showed no effect on the upregulation of ALPK1 and p-NF-κB p65 induced by ALPK1 over-expression.

CONCLUSION

ALPK1 promotes cardiomyocyte hypertrophy by activating NF-κB/NLRP3 inflammasome-mediated pyroptosis, providing new potential applications for agents targeting ALPK1 in the immunotherapy of cardiac hypertrophy.