Abstract 9781: Deletion of Prolyl Hydroxylase Domain Protein 2 in Myeloid Lineage suppressed Experimental Abdominal Aortic Aneurysm via NF-κB Inactivation

Abstract

Background: Macrophage migration to the vessels is important for vascular inflammation and induces vascular degenerative diseases. Macrophages secrete matrix metalloprotainases (MMPs), which activate many cytokines and digest extracellular matrix of aorta. MMPs play an important role in the progression of aortic aneurysm. We previously reported that non-specific prolyl hydroxylase domain protein (PHD) inhibitor, Cobalt chloride (CoCl2), suppressed MMP-2 and -9 expression and attenuated experimental abdominal aortic aneurysm (AAA) formation in mice. In this report we investigated the myeloid specific PHD2 knockout effect on MMPs expression and aneurysm formation. Methods: Myeloid specific PHD2 conditional knockout (MyPHD2KO) mice were generated. Experimental AAA was induced by periaortic application of Calcium chloride (CaCl2) for 6 weeks. In vitro Lipopolysaccharide (LPS, 100ng/ml) was used to induce MMP-2 and MMP-9 expression with peritoneal macrophages. MMPs mRNA, protein expression and protein activity were analyzed by qRT-PCR, Western blot analysis and Zymography, respectively. ELISA-based NF-κB p65 Transcription Factor Assay was used to examine NF-κB p65 binding activity with consensus DNA binding site. Results: CaCl2-induced AAA was suppressed with MyPHD2KO mice (max diameter of aneurysm: 1.03mm±0.14mm in MyPHD2KO group, 1.63mm±0.34mm in Control AAA group, p<0.01). In peritoneal macrophages CoCl2 reduced LPS-induced MMP-2 and MMP-9 mRNA and protein expression. PHD2 deletion in peritoneal macrophages from MyPHD2KO mice also suppressed LPS-induced MMP-2 and MMP-9 mRNA, protein expression and activity. PHD2 deletion suppressed LPS-induced NF-κB p65 phosphorylation via IκBα stabilization by Western blot analysis. NF-κB p65 binding activity was suppressed in MyPHD2KO macrophages (p<0.01 vs control). Conclusion: Deletion of PHD2 in myeloid lineage attenuated MMPs expression by NF-κB inactivation and suppressed AAA formation. PHD2 in macrophage may be a novel target for cardiovascular disease treatment.