Long-Term Stable Expression of Human Apolipoprotein A-I Mediated by Helper-Dependent Adenovirus Gene Transfer Inhibits Atherosclerosis Progression and Remodels Atherosclerotic Plaques in a Mouse Model of Familial Hypercholesterolemia

Abstract

Background-Epidemiologic studies and transgenic mouse experiments indicate that high plasma HDL and apolipoprotein (apo) A-I protect against atherosclerosis. We used helper-dependent adenovirus (HD-Ad) gene transfer to examine the effect of long-term hepatic apoA-I expression on atherosclerotic lesion progression and remodeling in a mouse model of familial hypercholesterolemia. Methods and Results-We treated LDL receptor-deficient (LDLR Ϫ/Ϫ ) mice maintained on a high-cholesterol diet for 6 weeks with either a HD-Ad containing human apoA-I gene (HD-Ad-AI) or saline (control). HD-Ad-AI treatment did not affect plasma liver enzymes but induced the appearance of plasma human apoA-I at or above human levels for the duration of the study. Substantial amounts of human apoA-I existed in lipid-free plasma. Compared with controls, HDLs from treated mice were larger and had a greater inhibitory effect on tumor necrosis factor-␣-induced vascular cellular adhesion molecule-1 expression in cultured endothelial cells. Twenty-four weeks after injection, aortic atherosclerotic lesion area in saline-treated mice progressed Ϸ700%; the rate of progression was reduced by Ͼ50% by HD-Ad-AI treatment. The lesions in HD-Ad-AI-treated mice contained human apoA-I that colocalized mainly with macrophages; they also contained less lipid, fewer macrophages, and less vascular cellular adhesion molecule-1 immunostaining but more smooth muscle cells (␣-actin staining) and collagen. Conclusions-HD-Ad-AI treatment of LDLRϪ/Ϫ mice leads to long-term overexpression of apoA-I, retards atherosclerosis progression, and remodels the lesions to a more stable-appearing phenotype. HD-Ad-mediated transfer of apoA-I may be a useful clinical approach for protecting against atherosclerosis progression and stabilizing atherosclerotic lesions associated with dyslipidemia in human patients.

Sustained phenotypic correction in a mouse model of hypoalphalipoproteinemia with a helper-dependent adenovirus vector

“…In contrast, HDAds have a significantly better safety profile and duration of transgene expression. [8][9][10][11][12][13][14] In this study, we compared the acute and chronic toxicities of HDAd and FGAd. Chronic hepatotoxicity caused by leaky Ad viral gene expression manifested by abnormal histopathology occurs with an FGAd, but is eliminated in a HDAd ( Figure 3, Table 1).…”

“…Helper-dependent Ads (HDAds) are devoid of all viral protein genes; they display greatly attenuated toxicity and prolonged transgene expression following liver transduction in vivo. [8][9][10][11][12][13][14] In this investigation, we examined the effect of Ad-mediated gene transfer of the human APOA1 gene to the liver of APOA1 À/À mice, a mouse model for human familial hypoalphalipoproteinemia, to reverse the low HDL levels. We compared the efficacy of HDAd and firstgeneration Ad (FGAd-AI)-expressing human APOA1 gene to reverse the phenotype of mice with a congenital HDL deficiency.…”

Low-density lipoprotein receptor gene therapy using helper-dependent adenovirus produces long-term protection against atherosclerosis in a mouse model of familial hypercholesterolemia

“…15 Histological and immunohistochemical studies were performed on fresh-frozen OCT-embedded proximal aortic sections (5 mm thick). Immunohistochemistry was performed as described 14 using the following primary antibodies: goat anti-human LDLR, c-20 (Santa Cruz Biotechnology, 1:100); rabbit anti-mouse macrophage (Accurate Chemical); rabbit anti-smooth muscle actin (Spring Bioscience, 1:100); and rabbit anti-mouse VCAM-1 (Santa Cruz Biotechnology, 1:100).…”

“…10 The transient and incomplete nature of the lipid lowering after LDLR gene therapy using either FG-Ad or AAV is related at least in part to an immune response against the induced LDLR expression in mice lacking LDLR. 10,11 The helper-dependent Ad (HD-Ad) [12][13][14] is the latest generation Ad that has been shown to have high transduction efficiency in vivo, and the transfer of apolipoprotein (apo) E to the liver of apoE À/À mice by this vector produced lifetime phenotypic correction of the hypercholesterolemia. 13 In this study we tested the efficacy of HD-Ads in the treatment of LDLR À/À mice.…”

Apolipoprotein A-I and lecithin:cholesterol acyltransferase transfer induce cholesterol unloading in complex atherosclerotic lesions

“…17,18,[20][21][22] Obviously, prior studies in human apo A-I and human Lcat transgenic rabbits 3,23 were not hampered by an immune response against human apo A-I or human LCAT, because tolerance for these transgene products develops during fetal life.…”