A novel endothelial cell-based gene therapy platform for the in vivo delivery of apolipoprotein E

Abstract

A major focus in gene therapy has been the use of recomand lesions at a young age. After transplantation of the binant viruses to deliver genes in vivo. Although this apoE secreting Pro 175 endothelial cells into apoEapproach shows much promise, there are many safety deficient mice, serum cholesterol levels were measured at concerns associated with the use of viral materials in the 2 week intervals. During the 3 months after the initiation of treatment of human diseases. Our alternative cell-based these experiments, levels of cholesterol in the animals havgene therapy approach utilizes endothelial cells (Pro 175) ing received the apoE secreting endothelial cells were statisolated from the murine embryonic yolk sac. These endoistically lower compared with the levels of age-matched thelial cells were evaluated for their potential use in gene controls having received non-secreting endothelial cells. therapy as a gene delivery platform. As a test model, we Concomitant with cholesterol reduction, atherosclerotic used these cells to deliver apolipoprotein E (apoE) in the aortic plaques were noticeably reduced in the experimental murine apoE knockout atherosclerosis model. The lack of apoE+ animals. These results highlight the potential of apoE protein in these animals results in high levels of these unique endothelial cells as an efficient delivery serum cholesterol and formation of severe aortic plaques platform for somatic gene therapy.

Treatment of severe hypercholesterolemia in apolipoprotein E-deficient mice by intramuscular injection of plasmid DNA

“…The normalization or reduction of the cholesterolemia after apoE3 gene transfer or normal bone marrow transplantation in apoE knockout mice has been demonstrated even in the absence of detectable levels of serum apoE. 10,27 The complex of these results definitely prove the hypothesis that very small amount of apoE are sufficient to enhance hepatic clearance of VLDL and IDL cholesterol in apoE knock-out mice. 27,32 Using fast protein liquid chromatography (FPLC) analysis we showed that the decrease in total serum cholesterol was accompanied by changes in the serum lipoproteins distribution.…”

“…26 One possible explanation is the rapid cycling due to the high levels of cholesterol. 10 In fact, apoE protein could be quickly associated with lipids, taken up by the cells and transported to the tissues, thus resulting in a low serum concentration in these animals. In mice a large portion of the hepatic apoB (a ligand for the LDL-R along with apoE) is truncated (apo B48) and does not contain the LDL-R binding domain.…”

“…8,9 Lastly, endothelial cells and epidermal keratinocytes expressing the apoE have also been used. 10,33 Because of its unique properties, skeletal muscle was chosen in our study as the target tissue for gene transfer. 12,34 Currently available vectors for gene delivery to muscle include several viral vectors.…”

“…8,9 Furthermore, cholesterol reduction has recently been demonstrated after transplantation of apoE secreting endothelial cells into apoE-deficient mice. 10 These findings highlight the great opportunity offered by apoE gene replacement.…”

Cell-derived Apolipoprotein E (ApoE) Particles Inhibit Vascular Cell Adhesion Molecule-1 (VCAM-1) Expression in Human Endothelial Cells

“…Although our transfection studies are not directly relevant to the situation in vivo, as endothelium does not synthesize apoE, they do have implications for gene therapy; transfecting endothelial cells to express apoE may limit endothelial activation. Indeed, this approach prevents lesion development in apoE-deficient mice (34).…”