MCC950 ameliorates ventricular arrhythmia vulnerability induced by heart failure

Abstract

MCC950, a specific NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inhibitor, has been reported to play a role in various cardiovascular diseases. However, its role in heart failure (HF)-induced ventricular arrhythmias (VAs) remains unclear. Hence, the present study aimed to clarify the role and underlying mechanisms of MCC950 in HF-induced VAs. Male C57BL/6 mice were induced with HF via transverse aortic constriction (TAC). Histological analysis, echocardiography, electrophysiological investigation, and western blot analysis were conducted to evaluate VA vulnerability induced by TAC and the potential mechanisms underlying the effects. MCC950 markedly improved cardiac function and decreased pulmonary edema induced by HF. Moreover, MCC950 also decreased VA vulnerability, as shown by the shortened QTc duration and action potential duration 90 (APD₉₀), reduced APD alternans threshold, and decreased VA induction rate. Furthermore, MCC950 treatment significantly reversed TAC-induced cardiac hypertrophy and fibrosis. In addition, MCC950 administration increased the protein levels of ion channels (Kv4.2, KChIP2, and Cav1.2). Mechanistically, the above changes induced by MCC950 were due to the inhibition of the NLRP3 inflammasome. As a specific NLRP3 inhibitor, MCC950 significantly decreased HF-induced VA vulnerability by reversing cardiac structural remodeling and electrical remodeling, and the mechanism through which MCC950 exhibited this effect was inhibition of NLRP3 inflammasome activation.

Keywords: MCC950; NLRP3 inflammasome; heart failure; ventricular arrhythmias.

Graphical abstract

Figure 1.

MCC950 impact on cardiac function in HF mice (a) Representative mouse M-mode echocardiograms. (b) LVEDD, (c) LVESD, (d) LVEF, and (e) LVFS values of the mice in each group are presented (n = 6). (f) LW/BW and (g) LW/TL values of the mice in each group are presented (n = 6). Data are expressed as the mean ± SEM. *P < 0.05 vs. sham, ^#P < 0.05 vs. HF-PBS.

Figure 2.

Analysis of surface electrocardiograph in the three groups of mice. (a) A representative trace of surface electrocardiograph for each of the three groups. Surface electrocardiograph parameters of RR duration (b), PR duration (c), QRS duration (d), and QTc duration (e) in the three groups. Data are expressed as the mean ± SEM. *P < 0.05 vs. sham, ^# P < 0.05 vs. HF-PBS. NS, not significant, ^&P < 0.05 vs. sham.

Figure 3.

The effect of MCC950 on electrical remodeling and VA susceptibility in HF mice. (a, b) Representative action potential figures and statistical analysis of the APD₉₀ (n = 8). (c, d) Representative electric alternans figures and statistical analysis of the ALT thresholds (n = 8). (e, f) Representative arrhythmia induced by burst-pacing stimulations and statistical analysis (n = 9). Data are expressed as the mean ± SEM. *P < 0.05 vs. sham; ^#P < 0.05 vs. HF-PBS.

Figure 4.

MCC950 impact on myocardial hypertrophy after HF. (a) HW/BW and (b) HW/TL values of the mice in each group (n = 6). (c) Representative WGA staining of left ventricular tissues obtained from mice in each group (magnification, ×400). (d) Statistical analysis of the cardiomyocyte CSA from WGA-stained sections (n = 100+ cardiomyocytes in four samples). (e–g) Representative western blots and statistical analysis of the protein expression levels of the cardiac hypertrophy markers ANP and BNP in each group (n = 4). Data are expressed as the mean ± SEM. *P < 0.05 vs. sham; ^#P < 0.05 vs. HF-PBS, ^&P < 0.05 vs. sham.

Figure 5.

The effect of MCC950 on myocardial fibrosis following HF. (a) Representative Masson staining of myocardial tissues (magnification, ×400). (b) Statistical analysis of the LV collagen volume (%) in Masson-stained sections (n = 6). (c–e) Representative western blots and statistical analysis of the protein expression levels of the cardiac fibrosis markers α-SMA and collagen I in each group. Data are expressed as the mean ± SEM. *P < 0.05 vs. sham; ^#P < 0.05 vs. HF-PBS, ^&P < 0.05 vs. sham.

Figure 6.

MCC950 impact on the protein expression of ion channels in HF mice. (a–d) Representative western blots and statistical analysis of Kv4.2, KChIP2, and Cav 2.1 in each group. Data are expressed as the mean ± SEM. * P < 0.05 vs. sham; ^#P < 0.05 vs. HF-PBS, ^&P < 0.05 vs. sham.

Figure 7.

The effect of MCC950 on NLRP3 signaling following HF. Representative western blots (a) and statistical analysis of the protein expression levels of cardiac NLRP3 (b), ASC (c), caspase-1 (d), IL-1β (e), and IL-18 (f) in each group (n = 4). Data are expressed as the mean ± SEM. *P < 0.05 vs. sham; ^#P < 0.05 vs. HF- HF-PBS, ^&P < 0.05 vs. sham.