Abstract 676: Microrna-30 and Cthrc1: Translating Aging into Vascular Stiffness and Abdominal Aortic Aneurysm
Abdominal aortic aneurysm (AAA) is a major source of vascular morbidity and mortality, with increasing age representing one of the strongest risk factors. While increases in aortic extra-cellular matrix deposition may be protective, changes in vessel architecture with age result in heterogeneous stiffness and vascular calcification, which appear to pre-dispose to AAA development. MicroRNAs (miRs) are key regulators of vascular homeostasis and pathobiology.
Array profiling and qRT-PCR of aneurysmal aortic tissue in a murine AAA model (elastase-infused C57/B6) showed significant down-regulation of the miR-30 family, which is believed to have a role in vascular calcification. Increased age augmented this response, particularly for miR-30a, 30b and 30c. RNASeq profiling of a related AAA model (Ang-II in ApoE-/- KO) showed similar aortic down-regulation. Further, of differentially down-regulated miRs, miR-30 had the highest inverse correlation with mRNA gene targets. One predicted target - Cthrc1 (collagen triple helix repeat containing-1) - was the most consistently and significantly up-regulated gene across all time points in the AAA models. The protein resides within vascular smooth muscle cells (SMCs) and fibroblasts, responds to injury, and may regulate collagen expression and deposition. Immunofluorescence staining of AAA vs. normal aortas revealed increased expression of CTHRC1.
We further found that miR-30 family members bind to the CTHRC1 3’ UTR and regulate gene expression in vitro, and that antagomir suppression of miR-30 upregulates CTHRC1 in SMCs. We also demonstrated that signaling pathways known to increase in activity with aging within the aorta, and which are associated with vascular calcification and fibrosis (e.g. IL6-based inflammatory signaling, TGF-β signaling, and BMP-2 signaling) down-regulate miR-30 family expression in SMCs, and inversely up-regulate CTHRC1 expression. Forced overexpression of miR-30 in SMC in vitro down-regulates RUNX2, a key promoter of vascular stiffness and calcification. Taken together, these results suggest a significant role for miR-30 in pathways related to matrix deposition and calcification, regulating aortic pathobiology and age-related susceptibility to AAA.
Author Disclosures: J.M. Spin: None. W.H. Zheng: None. M. Adam: None. U. Raaz: None. I. Schellinger: None. Y. Kayama: None. K. Toyama: None. A. Deng: None. L. Maegdefessel: None. P.S. Tsao: None.
- © 2015 by American Heart Association, Inc.