Macrophage-driven NLRP3 inflammasome activation impairs cardiomyocyte function in HFpEF
C Dong, N HamdaniAbstract
Background
Heart failure with preserved ejection fraction (HFpEF) is characterized by diastolic dysfunction and myocardial inflammation, but the cellular mechanisms linking immune activation to cardiomyocyte injury remain incompletely understood. We investigated whether macrophage-driven NLRP3 inflammasome activation mediates cardiomyocyte dysfunction in HFpEF.
Methods
Cardiac macrophage infiltration, NLRP3 inflammasome activation, and NF-κB nuclear translocation were assessed in HFpEF mouse hearts and human heart specimens by immunostaining, ELISA and Western blot. Human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were exposed to conditioned media from macrophages to evaluate NF-κB activation, mitochondrial function, and calcium handling. Pharmacological inhibition (MCC950), siRNA knockdown (NLRP3), and GLP-1 receptor agonist treatment were applied in vitro to assess rescue effects.
Results
HFpEF hearts exhibited increased macrophage accumulation accompanied by enhanced NLRP3 inflammasome activation, as evidenced by elevated caspase-1 cleavage and mature IL-1β production. This was associated with increased NF-κB nuclear translocation in cardiomyocytes. In iPSC-CMs, macrophage-conditioned media induced robust NF-κB activation, mitochondrial fragmentation, oxidative stress, and impaired calcium transient. Pharmacological inhibition of NLRP3 with MCC950 or siRNA-mediated knockdown significantly reduced inflammatory responses. GLP-1 receptor agonist treatment also suppressed NLRP3 activation and IL-1β production, mitigating macrophage-driven inflammation.
Conclusions
Macrophage-driven NLRP3 inflammasome activation in HFpEF promotes NF-κB nuclear translocation in cardiomyocytes, contributing to functional impairment. Functional rescue by GLP-1RA, MCC950, or siRNA in iPSC-CMs highlights potential therapeutic avenues in vitro. These findings provide mechanistic insight into HFpEF-associated myocardial inflammation and suggest macrophage inflammasome signaling as a targetable axis.