Adenovirus-mediated gene transfer of rat apolipoprotein B mRNA-editing protein in mice virtually eliminates apolipoprotein B-100 and normal low density lipoprotein production.
Apolipoprotein (apo) B-100 is the major protein component in low density lipoprotein (LDL); it contains the binding domain for the LDL receptor and the attachment site for apolipoprotein(a) in lipoprotein(a). ApoB-48 is colinear with the amino-terminal half of apoB-100 and misses the part of the molecule required for LDL receptor interaction and lipoprotein(a) formation. ApoB-48 mRNA is produced by the editing of apoB-100 mRNA, a process by which the codon CAA for Gln-2153 is changed to UAA, an in-frame stop codon. We used the cloned catalytic component of the rat apoB mRNA-editing enzyme (REPR) to construct a replication-defective recombinant adenoviral vector containing REPR cDNA (AvREPR) and a control vector (Av1LacZ4) containing a beta-galactosidase cDNA to investigate the effect of REPR gene delivery in C57BL/6 mice. Intravenous injection of AvREPR in mice resulted in efficient transduction of liver cells, where REPR mRNA and protein were overexpressed, reaching a peak at 7 and 12 days, returning toward control levels at 39 days after AvREPR administration. ApoB mRNA editing activity in liver extracts showed changes parallel to those of REPR mRNA expression; the proportion of edited apoB mRNA in the total hepatic apoB mRNA increased from approximately 60% to more than 90% at the peak of REPR expression. The proportion of plasma apoB-100 in AvREPR-transduced animals decreased from approximately 50% to < 10% of total plasma apoB concentration. Plasma very low density lipoproteins were polydisperse in control animals with an average diameter of 54.9 +/- 20.6 nm (uninjected control) and 54.7 +/- 16.8 nm (Av1LacZ4-treated), respectively. They became much smaller (average diameter 39.3 +/- 12.7 nm) and more uniform in size at day 12 following AvREPR administration. On the same day, the normal plasma LDL (26.2-25.5 nm) was almost completely eliminated in treated animals. Adenovirus-mediated transfer of the REPR cDNA is an efficient method to reduce plasma apoB-100 and normal LDL production.
Department of Medicine, Baylor College of Medicine, Houston, Texas 77030.
B
B
Teng
S
S
Blumenthal
T
T
Forte
N
N
Navaratnam
J
J
Scott
A M
AM
Gotto
L
L
Chan
D000071479:APOBEC-1 Deaminase; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D053299:Apolipoprotein B-100; D053283:Apolipoprotein B-48; D001055:Apolipoproteins B / Q000096:biosynthesis* / Q000097:blood; D003564:Cytidine Deaminase / Q000235:genetics* / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D018014:Gene Transfer Techniques; D008077:Lipoproteins, LDL / Q000096:biosynthesis*; D008099:Liver / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D012323:RNA Processing, Post-Transcriptional; D051381:Rats; D011995:Recombination, Genetic; D014161:Transduction, Genetic; D000098830:AICDA (Activation-Induced Cytidine Deaminase)
D053299:Apolipoprotein B-100; D053283:Apolipoprotein B-48; D001055:Apolipoproteins B; D008077:Lipoproteins, LDL; D000098830:AICDA (Activation-Induced Cytidine Deaminase); D000071479:APOBEC-1 Deaminase; C000605090:Apobec1 protein, mouse; C000605091:Apobec1 protein, rat; D003564:Cytidine Deaminase