Inflammasome activity is essential for one kidney/deoxycorticosterone acetate/salt-induced hypertension in mice.

Abstract

Background and Purpose Inflammasomes are multimeric complexes that facilitate caspase-1-mediated processing of the pro-inflammatory cytokines IL-1beta and IL-18. Clinical hypertension is associated with renal inflammation and elevated circulating levels of IL-1beta and IL-18. Therefore, we investigated whether hypertension in mice is associated with increased expression and/or activation of the inflammasome in the kidney, and if inhibition of inflammasome activity reduces BP, markers of renal inflammation and fibrosis. Experimental Approach Wild-type and inflammasome-deficient ASC-/- mice were uninephrectomized and received deoxycorticosterone acetate and saline to drink (1K/DOCA/salt). Control mice were uninephrectomized but received a placebo pellet and water. BP was measured by tail cuff; renal expression of inflammasome subunits and inflammatory markers was measured by real-time PCR and immunoblotting; macrophage and collagen accumulation was assessed by immunohistochemistry. Key Results 1K/DOCA/salt-induced hypertension in mice was associated with increased renal mRNA expression of inflammasome subunits NLRP3, ASC and pro-caspase-1, and the cytokine, pro-IL-1beta, as well as protein levels of active caspase-1 and mature IL-1beta. Following treatment with 1K/DOCA/salt, ASC-/- mice displayed blunted pressor responses and were also protected from increases in renal expression of IL-6, IL-17A, CCL2, ICAM-1 and VCAM-1, and accumulation of macrophages and collagen. Finally, treatment with a novel inflammasome inhibitor, MCC950, reversed hypertension in 1K/DOCA/salt-treated mice. Conclusions and Implications Renal inflammation, fibrosis and elevated BP induced by 1K/DOCA/salt treatment are dependent on inflammasome activity, highlighting the inflammasome/IL-1beta pathway as a potential therapeutic target in hypertension.Copyright © 2015 The British Pharmacological Society.