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Defects of the LDL receptor in WHHL transgenic rabbits lead to a marked accumulation of plasma lipoprotein[a]

Authors :
Teruo Watanabe
Mireille Challah
Jianglin Fan
Masashi Shiomi
Santica M. Marcovina
Hiroaki Shimoyamada
Source :
Journal of Lipid Research, Vol 41, Iss 6, Pp 1004-1012 (2000), Scopus-Elsevier
Publication Year :
2000
Publisher :
Elsevier, 2000.

Abstract

In this study, we created LDL receptor (LDLr) defective (WHHL) transgenic rabbits expressing human apo[a] to examine whether LDLr mediates the Lp[a] clearance from the plasma. By crossbreeding WHHL rabbits with human apo[a] transgenic rabbits, we obtained two groups of human apo[a] transgenic rabbits with defective LDLr functions: apo[a](1/0) WHHL heterozygous (LDLr(+/-) and apo[a](+/0) WHHL homozygous (LDLr(-/-) rabbits. The lipid and lipoprotein levels of human apo[a] WHHL rabbits were compared to those of human apo[a] transgenic rabbits with normal LDLr functions (LDLr(+/+). The apo[a] production rate was evaluated by analyzing apo[a] mRNA expression in the liver, the major site for apo[a] synthesis in transgenic rabbits. We found that pre-beta lipoproteins were markedly increased accompanied by a 2-fold increase in the plasma Lp[a] in apo[a](+/0)/LDLr(+/-) rabbits and a 4.2-fold increase in apo[a](+/0)/LDLr(-/-) rabbits compared with that in apo[a](+/0) rabbits with normal LDLr function. In apo[a](+/0)/LDLr(-/-) rabbits, there was a marked increase in plasma total cholesterol and triglycerides, as was found in their counterpart non-transgenic WHHL rabbits. Northern blot analysis revealed that hepatic apo[a] expression in WHHL transgenic rabbits was similar to that in LDLr(+/+) transgenic rabbits, suggesting the accumulation of plasma Lp[a] in WHHL transgenic rabbits was not due to increased apo[a] synthesis. In conclusion, absence of a functional LDLr leads to a marked accumulation of plasma Lp[a] in human apo[a] transgenic WHHL rabbits and LDLr may participate in the catabolism of Lp[a] in rabbits.

Details

Language :
English
ISSN :
00222275
Volume :
41
Issue :
6
Database :
OpenAIRE
Journal :
Journal of Lipid Research
Accession number :
edsair.doi.dedup.....8b02dc2fbfdc0c4e7ab430c06a419a4a