Objective:
The goal of this study was to determine the role of ZFP148 in aneurysm formation.
Approach and Results:
ZFP148 mRNA expression increased at day 3, 7, 14, 21 and 28 following during AAA formation in C57BL/6 mice. Loss of ZFP148 conferred AAA protection using ERTCre+ ZFP148 flx/flx mice. In a third set of experiments, smooth muscle specific loss of ZFP148 alleles resulted in progressively greater protection using novel transgenic mice (MYHCre+ flx/flx, flx/wt, and wt/wt). Elastin degradation, LGAL3, and Neutrophil staining were significantly attenuated, while α-actin staining was increased in ZFP148 knock-out mice. Results were verified in total cell ZFP148 and smooth muscle specific knock-out mice using an Angiotensin II model, .ZFP148 smooth muscle specific conditional mice demonstrated increased proliferation and ZFP148 was shown to bind to the p21 promoter during AAA formation. ZFP148 smooth muscle specific conditional knock-out mice also demonstrated decreased apoptosis as measured by decreased cleaved Caspase-3 staining. ZFP148 bound smooth muscle marker genes via ChIP analysis mediated by NF-1 promote histone H3K4 de-acetylation via Histone De-acetylase 5. Transient transfections and ChIP analyses demonstrated that NF-1 was required for ZFP148 protein binding to Smooth Muscle marker genes promoters during aneurysm formation. Elimination of NF-1 using shRNA approaches demonstrated that NF-1 is required for binding and elimination of NF-1 increased BRG1 recruitment, the ATPase subunit of the SWI/SWF complex, and increased histone acetylation.
Conclusions:
ZFP148 plays a critical role in multiple murine models of aneurysm formation. These results suggest that ZFP148 is important in the regulation of proliferation, smooth muscle gene down-regulation and apoptosis in aneurysm development.