| First Author | Tai HC | Year | 2016 |
| Journal | Hypertension | Volume | 67 |
| Issue | 6 | Pages | 1298-308 |
| PubMed ID | 27045031 | Mgi Jnum | J:280127 |
| Mgi Id | MGI:6369308 | Doi | 10.1161/HYPERTENSIONAHA.116.07367 |
| Citation | Tai HC, et al. (2016) Peroxisome Proliferator-Activated Receptor gamma Level Contributes to Structural Integrity and Component Production of Elastic Fibers in the Aorta. Hypertension 67(6):1298-308 |
| abstractText | Loss of integrity and massive disruption of elastic fibers are key features of abdominal aortic aneurysm (AAA). Peroxisome proliferator-activated receptor gamma (PPARgamma) has been shown to attenuate AAA through inhibition of inflammation and proteolytic degradation. However, its involvement in elastogenesis during AAA remains unclear. PPARgamma was highly expressed in human AAA within all vascular cells, including inflammatory cells and fibroblasts. In the aortas of transgenic mice expressing PPARgamma at 25% normal levels (Pparg(C) (/-) mice), we observed the fragmentation of elastic fibers and reduced expression of vital elastic fiber components of elastin and fibulin-5. These were not observed in mice with 50% normal PPARgamma expression (Pparg(+/-) mice). Infusion of a moderate dose of angiotensin II (500 ng/kg per minute) did not induce AAA but Pparg(+/-) aorta developed flattened elastic lamellae, whereas Pparg(C/-) aorta showed severe destruction of elastic fibers. After infusion of angiotensin II at 1000 ng/kg per minute, 73% of Pparg(C/-) mice developed atypical suprarenal aortic aneurysms: superior mesenteric arteries were dilated with extensive collagen deposition in adventitia and infiltrations of inflammatory cells. Although matrix metalloproteinase inhibition by doxycycline somewhat attenuated the dilation of aneurysm, it did not reduce the incidence nor elastic lamella deterioration in angiotensin II-infused Pparg(C/-) mice. Furthermore, PPARgamma antagonism downregulated elastin and fibulin-5 in fibroblasts, but not in vascular smooth muscle cells. Chromatin immunoprecipitation assay demonstrated PPARgamma binding in the genomic sequence of fibulin-5 in fibroblasts. Our results underscore the importance of PPARgamma in AAA development though orchestrating proper elastogenesis and preserving elastic fiber integrity. |
