P5363
A novel non-hypoxic and sex-biased mechanism of HIF-1alpha in human aortic valve interstitial cells: crosstalk between JAK-STAT and TLR pathways

Extract

Introduction: Immune cell infiltration is one of the earliest events in calcific aortic valve disease (CAVD). Recent data showed that infiltrated T lymphocytes secrete active interferon (IFN)-γ, the effects of which in resident valve cells remain unknown. In addition, angiogenesis has been pointed out as a key player in CAVD since new vessels formation and hypoxia-inducible factor (HIF)-1α have been detected in calcified aortic valves. However, its underlying molecular mechanisms are still poorly understood.

Purpose: To elucidate the role of IFN-γ on inflammation, angiogenesis and calcification of human aortic valve interstitial cells (AVIC) isolated from male and female patients.

Methods: AVIC were isolated from healthy valves by collagenase digestion and exposed to IFN-γ and/or lipopolysaccharide (LPS). Western Blot and ELISA were used to analyze pro-inflammatory and pro-angiogenic molecules. The osteogenic marker bone morphogenetic protein (BMP)-2 and the anti-angiogenic factor chondromodulin-1 (ChM-I) were analyzed by RT-qPCR. Immunofluorescence was used to evaluate HIF-1α nuclear translocation. Alizarin red staining and calcium deposits quantitation were performed to evaluate in vitro calcification of AVIC in high-phosphate conditions.