Interferon-γ Signaling Inhibition Ameliorates Angiotensin II-Induced Cardiac Damage

Angiotensin (Ang) II induces vascular injury in part by activating innate and adaptive immunity; however, the mechanisms are unclear. We investigated the role of interferon (IFN)-gamma and interleukin (IL)-23 signaling. We infused Ang II into IFN-gamma receptor (IFN-gamma R) knockout mice and wild-type controls, as well as into mice treated with neutralizing antibodies against IL-23 receptor and IL-17A. Ang II-treated IFN-gamma R knockout mice exhibited reduced cardiac hypertrophy, reduced cardiac macrophage and T-cell infiltration, less fibrosis, and less arrhythmogenic electric remodeling independent of blood pressure changes. In contrast, IL-23 receptor antibody treatment did not reduce cardiac hypertrophy, fibrosis, or electric remodeling despite mildly reduced inflammation. IL-17A antibody treatment behaved similarly. In the kidney, IFN-gamma R deficiency reduced inflammation and tubulointerstitial damage and improved glomerular filtration rate. Nonetheless, albuminuria was increased compared with Ang II-treated wild-type controls. The glomeruli of Ang II-treated IFN-gamma R knockout mice exhibited fewer podocytes, less nephrin and synaptopodin staining, and impaired podocyte autophagy. Thus, IFN-gamma blockade, but not IL-23 receptor antibody treatment, protects from Ang II-induced cardiac damage and electric remodeling. In the kidney, IFN-gamma signaling acts in a cell type-specific manner. Glomerular filtration rate is preserved in the absence of the IFN-gamma R, whereas podocytes may require the IFN-gamma R in the presence of Ang II for normal integrity and function. (Hypertension. 2012;60:1430-1436.)