Inhibition of the NLRP3/IL‐1β axis protects against sepsis‐induced cardiomyopathy

Abstract

Background Septic cardiomyopathy worsens the prognosis of critically ill patients. Clinical data suggest that interleukin‐1β (IL‐1β), activated by the NLRP3 inflammasome, compromises cardiac function. Whether or not deleting Nlrp3 would prevent cardiac atrophy and improve diastolic cardiac function in sepsis was unclear. Here, we investigated the role of NLRP3/IL‐1β in sepsis‐induced cardiomyopathy and cardiac atrophy. Methods Male Nlrp3 knockout (KO) and wild‐type (WT) mice were exposed to polymicrobial sepsis by caecal ligation and puncture (CLP) surgery (KO, n = 27; WT, n = 33) to induce septic cardiomyopathy. Sham‐treated mice served as controls (KO, n = 11; WT, n = 16). Heart weights and morphology, echocardiography and analyses of gene and protein expression were used to evaluate septic cardiomyopathy and cardiac atrophy. IL‐1β effects on primary and immortalized cardiomyocytes were investigated by morphological and molecular analyses. IonOptix and real‐time deformability cytometry (RT‐DC) analysis were used to investigate functional and mechanical effects of IL‐1β on cardiomyocytes. Results Heart morphology and echocardiography revealed preserved systolic (stroke volume: WT sham vs. WT CLP: 33.1 ± 7.2 μL vs. 24.6 ± 8.7 μL, P < 0.05; KO sham vs. KO CLP: 28.3 ± 8.1 μL vs. 29.9 ± 9.9 μL, n.s.; P < 0.05 vs. WT CLP) and diastolic (peak E wave velocity: WT sham vs. WT CLP: 750 ± 132 vs. 522 ± 200 mm/s, P < 0.001; KO sham vs. KO CLP: 709 ± 152 vs. 639 ± 165 mm/s, n.s.; P < 0.05 vs. WT CLP) cardiac function and attenuated cardiac (heart weight–tibia length ratio: WT CLP vs. WT sham: −26.6%, P < 0.05; KO CLP vs. KO sham: −3.3%, n.s.; P < 0.05 vs. WT CLP) and cardiomyocyte atrophy in KO mice during sepsis. IonOptix measurements showed that IL‐1β decreased contractility (cell shortening: IL‐1β: −15.4 ± 2.3%, P < 0.001 vs. vehicle, IL‐1RA: −6.1 ± 3.3%, P < 0.05 vs. IL‐1β) and relaxation of adult rat ventricular cardiomyocytes (time‐to‐50% relengthening: IL‐1β: 2071 ± 225 ms, P < 0.001 vs. vehicle, IL‐1RA: 564 ± 247 ms, P < 0.001 vs. IL‐1β), which was attenuated by an IL‐1 receptor antagonist (IL‐1RA). RT‐DC analysis indicated that IL‐1β reduced cardiomyocyte size (P < 0.001) and deformation (P < 0.05). RNA sequencing showed that genes involved in NF‐κB signalling, autophagy and lysosomal protein degradation were enriched in hearts of septic WT but not in septic KO mice. Western blotting and qPCR disclosed that IL‐1β activated NF‐κB and its target genes, caused atrophy and decreased myosin protein in myocytes, which was accompanied by an increased autophagy gene expression. These effects were attenuated by IL‐1RA. Conclusions IL‐1β causes atrophy, impairs contractility and relaxation and decreases deformation of cardiomyocytes. Because NLRP3/IL‐1β pathway inhibition attenuates cardiac atrophy and cardiomyopathy in sepsis, it could be useful to prevent septic cardiomyopathy.

Sepsis induces interleukin 6, gp130/JAK2/STAT3, and muscle wasting

“…Cecal ligation and puncture (CLP) surgery was performed in 12-to 16-week-old male Il6st cKO mice and WT littermate controls, as recently described. 10,25 Sham mice were treated identically except for the ligation and puncture of the cecum. The effects of AG490 treatment on sepsis-induced muscle atrophy were investigated in 20-week-old male C57BL/6J mice.…”

Out of Control: The Role of the Ubiquitin Proteasome System in Skeletal Muscle during Inflammation

“…Accordingly, septic Nlrp3-deficient mice showed a reduced activation of NF-κB, which was accompanied by a decrease in atrogin-1/MAFbx and MuRF1 expression when compared with wildtype littermate controls. Because Nlrp3 deletion reduces mortality and sepsis-induced end-organ damage, such as muscle failure [195], cardiomyopathy [250,251] and acute lung injury, pharmacological NLRP3 inhibition might be beneficial in sepsis. Indeed, positive effects were reported for the NLRP3-inhibitors hemin, which protected against cecal ligation and puncture (CLP)-induced acute lung injury in mice [252], and scutellarin as well as glyburide, which improved survival of mice with bacterial sepsis [253,254].…”

Harmine Alleviated Sepsis-Induced Cardiac Dysfunction by Modulating Macrophage Polarization via the STAT/MAPK/NF-κB Pathway

“…When exposed to diverse stimuli, such as LPS, TNF- α and IFN- γ , M1 macrophages are activated, and intracellular inflammatory and metabolic reprogramming pathways are activated, including STAT1, NF-κB and HIF-1 α axes, eventually promoting the generation of plentiful cytokines that damage cardiomyocytes and then induce cardiac dysfunction ( Y. Liu et al, 2017 ; Chen et al, 2021 ). Moreover, other bioactive factors, such as PGE2, TXB2 ( Amunugama et al, 2021 ), NO ( Jia et al, 2018 ) and NLRP3 ( Busch et al, 2021 ), are reported to facilitate inflammation progression and tissue injury during the course of sepsis. However, to date, the specific mechanisms responsible for SIC remain elusive.…”

“…Liu et al, 2017;Chen et al, 2021). Moreover, other bioactive factors, such as PGE2, TXB2 (Amunugama et al, 2021), NO (Jia et al, 2018) and NLRP3 (Busch et al, 2021), are reported to facilitate inflammation progression and tissue injury during the course of sepsis. However, to date, the specific mechanisms responsible for SIC remain elusive.…”