Abstract
Introduction and Hypothesis: The ubiquitin-conjugating enzyme, galactosyltransferase 1-associating protein (GTAP), is an E2 ubiquitin-conjugating enzyme (UBE2q1), involved in stem cell proliferation and differentiation. Increased vascular smooth muscle cell (SMC) calcification characterizes atherosclerotic heart disease. We tested here the hypothesis that GTAP plays a role in regulation of SMC calcification and expression of the osteogenic protein Runx2. Methods and Results: Echocardiography was conducted in sv129 (WT) (n=10) and GTAP-knockout (GTAP -/- ) (n=11) mice, displayed reduced contractility in GTAP -/- vs. WT mice. In histopathology patch myocardial fibrosis, arterial hyperplasia and calcification occurred in GTAP -/- but not WT mice. Significantly increased calcium contents/dry proteins were found in the aortic rings of GTAP -/- vs. WT mice when ex vivo exposed to inorganic phosphate media for 9 days (Fig. 1a, p<0.05). To less extents, heterozygous GTAP -/+ mice also had increased calcium contents. Total proteins were extracted from aortic SMC transduced with cDNA coding for WT GTAP and loss-functional mutant GTAP C351A for Western blot assays. As shown in Fig. 1b, compared with mock treated SMC, WT GTAP overexpressing SMC had increased band intensity of the contractile proteins, α-SM-actin and SM22α, but much lower band intensity of Runx2 protein. SMC with overexpression of the GTAP C351A mutant modestly reduction in Runx2 band density, and had little impact on band intensity of the contractile protein α-SM-actin and SM22α. Conclusions: GTAP exerts protective effects on vascular SMC by inhibiting expression of Runx2 and calcification, while promoting expression of the contractile proteins, α-SM-actin and SM22α.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.