Abstract 14150: Ectopic Wild Type Gene Transfer Successfully Corrects Vascular Smooth Muscle Phenotypes of Adipose Tissue Triglyceride Lipase Deficient Mouse
Background: Hereditary mutated adipose tissue triglyceride lipase (ATGL) causes triglyceride-deposit cardiovasculopathy (TGCV). In addition to cardiomyocyte steatosis, coronary atherosclerosis in the patients with TGCV exacerbates heart failure. However, little was known regarding atherogenesis in TGCV. To investigate the mechanism of vasculopathy in ATGL deficient condition, we characterized SMC of ATGL knockout mouse (ATGLKO). Therapeutic intervention was attempted using recombinant adenovirus system in vitro.
Methods and Results: Aortic SMC were isolated from ATGLKO and control B6 mice with the explant method. SMC of ATGLKO showed spontaneous triglyceride (TG) accumulation with low proliferative activity and senescent cell-like morphology, which was not correlated with alpha-smooth muscle actin induction. Gene expression profiles were screened with DNA array followed by real-time PCR. SMC of ATGLKO represented higher expression of glucokinase (1.7 fold) and lipoprotein lipase (3.8 fold) than those in the control. Reduced expressions of TGF-β (0.4 fold) and type I collagen (0.5 fold), and up-regulated IL-6 expression (3.7 fold) were noted. Ectopic gene transfer was performed using tetracycline-regulatable ATGL-myc-DDK adenovirus vector. Adenovirus expressing bacterial β-galactosidase (LZV) or doxycycline (DOX) free condition was used for the control. Ectopic expression of wild type ATGL in SMC of ATGLKO was resulted not only in the reduction of intracellular TG deposition but also in the recovery of proliferation rate (1.4 fold vs. LZV-infected cells) and the decrease in the number of senescence-associated β-galactosidase positive cells (by 30% vs. DOX free condition). Moreover, real-time PCR revealed that dysregulated gene expressions in SMC of ATGLKO were successfully corrected by ectopic ATGL expression.
Conclusion: Our data suggested that the lower mitogenic acivity and collagen productivity as well as upregulated cytokine expression are characteristic of SMC of ATGLKO, which may lead to plaque fragility and vascular inflammation in vivo. In conclusion, ATGL deficiency influences SMC phenotypes. Genetic manipulation of ATGL would be expected to correct the atherogenic phenotypes of TG-deposited SMC.
- © 2012 by American Heart Association, Inc.