Clinically used JAK inhibitor blunts dsRNA‐induced inflammation and calcification in aortic valve interstitial cells

Calcific aortic valve disease (CAVD) is the most prevalent valvulopathy worldwide. Growing evidence supports a role for viral and cell‐derived double‐stranded (ds)‐RNA in cardiovascular pathophysiology. Poly(I:C), a dsRNA surrogate, has been shown to induce inflammation, type I interferon (IFN) responses, and osteogenesis through Toll‐like receptor 3 in aortic valve interstitial cells (VIC). Here, we aimed to determine whether IFN signaling via Janus kinase (JAK)/Signal transducers and activators of transcription (STAT) mediates dsRNA‐induced responses in primary human VIC. Western blot, ELISA, qPCR, calcification, flow cytometry, and enzymatic assays were performed to evaluate the mechanisms of dsRNA‐induced inflammation and calcification. Poly(I:C) triggered a type I IFN response characterized by IFN‐regulatory factors gene upregulation, IFN‐β secretion, and STAT1 activation. Additionally, Poly(I:C) promoted VIC inflammation via NF‐κB and subsequent adhesion molecule expression, and cytokine secretion. Pretreatment with ruxolitinib, a clinically used JAK inhibitor, abrogated these responses. Moreover, Poly(I:C) promoted a pro‐osteogenic phenotype and increased VIC calcification to a higher extent in cells from males. Inhibition of JAK with ruxolitinib or a type I IFN receptor blocking antibody blunted Poly(I:C)‐induced calcification. Mechanistically, Poly(I:C) promoted VIC apoptosis in calcification medium, which was inhibited by ruxolitinib. Moreover, Poly(I:C) co‐operated with IFN‐γ to increase VIC calcification by synergistically activating extracellular signal‐regulated kinases and hypoxia‐inducible factor‐1α pathways. In conclusion, JAK/STAT signaling mediates dsRNA‐triggered inflammation, apoptosis, and calcification and may contribute to a positive autocrine loop in human VIC in the presence of IFN‐γ. Blockade of dsRNA responses with JAK inhibitors may be a promising therapeutic avenue for CAVD.