Abstract / Summary
INTRODUCTION: Calcific aortic valve disease (CAVD) involves the osteogenic transition of valve interstitial cells (VICs) and is influenced by purinergic signaling. ATP is considered pro-calcific, whereas adenosine (Ado) has been reported as anti- or pro-calcific. Extracellular conversion of ATP to Ado by ecto-enzymes (including ecto-5’-nucleotidase, CD73) may shape receptor signaling in VICs. MATERIAL AND METHODS: We quantified osteogenic and apoptotic markers in the murine valve-like cell line tsA58-AVM under osteogenic conditions after treatment with ATP or Ado, selective Adora1/Adora2A agonists, and/or CD73. RESULTS: Runt-related transcription factor 2, isoform II (Runx2-II) expression decreased by 31% and 17% after 16 hours of exposure to 0.35 μM and 3.5 μM Ado, respectively. Adora1 activation (MeCCPA, 0.1 μM) reduced Runx2-II by 49–57% on days 1–5, and Adora2A activation (PSB0777, 1 μM) reduced Runx2-II by 17–63% at days 1–5. Repeated ATP addition (100 μM) increased osteopontin (SPP1) by 7.7- and 3.3-fold and osteocalcin (BGLAP) by 14.4- and 4.0-fold on days 5 and 12, respectively; cotreatment with CD73 (0.1 ng/μL) reduced or normalized these changes. ATP also doubled the Bcl-2- associated X protein (Bax) to B-cell lymphoma 2 protein (BCL2) ratio, an effect that was prevented by CD73. CONCLUSIONS: Purinergic ligands and receptors directly regulate VIC osteogenic differentiation and apoptosis in vitro without exogenous inflammatory stimulation. Modulation of the ATP-Ado axis may represent a therapeutic target to slow CAVD progression.