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Serelaxin inhibits the profibrotic TGF‐β1/IL‐1β axis by targeting TLR‐4 and the NLRP3 inflammasome in cardiac myofibroblasts
Author(s) -
Cáceres Felipe Tapia,
Gaspari Tracey A.,
Samuel Chrishan S.,
Pinar Anita A.
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.201901079rr
Subject(s) - inflammasome , relaxin , myofibroblast , chemistry , transforming growth factor , in vivo , fibrosis , medicine , endocrinology , inflammation , microbiology and biotechnology , pharmacology , receptor , biology , biochemistry
The recombinant form of the peptide hormone relaxin, serelaxin (RLX), mediates its anti‐fibrotic actions by impeding the profibrotic activity of cytokines including TGF‐β1 and IL‐1β. As IL‐1β can be produced by the nucleotide‐binding oligomerization domain, leucine‐rich repeat and pyrin domains‐containing protein 3 (NLRP3) inflammasome, this study determined whether RLX targeted the inflammasome to inhibit the profibrotic TGF‐β1/IL‐1β axis in primary human cardiac myofibroblasts (HCMFs) in vitro and in mice with isoproterenol (ISO)‐induced cardiomyopathy in vivo. HCMFs stimulated with TGF‐β1 (5 ng/ml), LPS (100 ng/ml), and ATP (5 mM) (T+L+A) for 8 h, to induce the NLRP3 inflammasome, demonstrated significantly increased protein expression of markers of NLRP3 priming (NLRP3, apoptosis‐associated speck‐like protein containing a C‐terminal caspase‐recruitment domain, procaspase‐1) and activity (IL‐1β, IL‐18). After 72 h, there was significantly increased neuronal NOS (nNOS), TLR‐4, procaspase‐1, myofibroblast differentiation, and collagen‐I deposition. These measures, along with interstitial TGF‐β1 expression and collagen deposition, were also increased in the left ventricle (LV) of ISO‐injured mice 14 d postinjury. RLX [16.8 nM (100 ng/ml) in vitro; 0.5 mg/kg per day in vivo ] inhibited T+L+A‐ and ISO‐induced TLR‐4 expression, NLRP3 priming, IL‐1β, IL‐18, myofibroblast differentiation, and interstitial collagen deposition at the time points studied, via the promotion of nNOS; with the NLRP3‐ and IL‐1β‐inhibitory effects of RLX in HCMFs being abrogated by pharmacological blockade of nNOS or TLR‐4. Comparatively, the small molecule NLRP3 inhibitor, N ‐{[(1,2,3,5,6,7‐hexahydro‐s‐indacen‐4‐yl)amino]carbonyl}‐4‐(1‐hydroxy‐1‐methylethyl)‐2‐furansulfonamide (1 μM in vitro, 10 mg/kg/d in vivo ), inhibited components of the NLRP3 inflammasome in vitro and in vivo and ISO‐induced interstitial LV fibrosis in vivo but did not affect nNOS, TLR‐4, myofibroblast differentiation, or myofibroblast‐induced collagen deposition. Hence, RLX can inhibit the TGF‐β1/IL‐1β axis via a nNOS‐TLR‐4‐NLRP3 inflammasome‐dependent mechanism on cardiac myofibroblasts.—Cáceres, F. T., Gaspari, T. A., Samuel, C. S., Pinar, A. A. Serelaxin inhibits the profibrotic TGF‐β1/IL‐1β axis by targeting TLR‐4 and the NLRP3 inflammasome in cardiac myofibroblasts. FASEB J. 33, 14717‐14733 (2019). www.fasebj.org