Functional LCAT deficiency in human apolipoprotein A-I transgenic, SR-BI knockout mice.
|
| Abstract |
Reduction of plasma LCAT activity has been observed in several conditions in which the size of HDL particles is increased; however, the mechanism of this reduction remains elusive. We investigated the plasma activity, mass, and in vivo catabolism of LCAT and its association with HDL particles in human apolipoprotein A-I transgenic, scavenger receptor class B type I knockout (hA-ITg SR-BI-/-) mice. Compared with hA-ITg mice, hA-ITg SR-BI-/- mice had a 4-fold higher total plasma cholesterol concentration, which occurred predominantly in 13-18 nm diameter HDL particles, a significant reduction in plasma esterified cholesterol-total cholesterol (EC/TC) ratio, and significantly lower plasma LCAT activity, suggesting a decrease in LCAT protein. However, LCAT protein in plasma, hepatic mRNA for LCAT, and in vivo turnover of 35S-radiolabeled LCAT were similar in both genotypes of mice. HDL from hA-ITg SR-BI-/- mice was enriched in sphingomyelin (SM), relative to phosphatidylcholine, and had less associated [35S]LCAT radiolabel and endogenous LCAT activity compared with HDL from hA-ITg mice. We conclude that the decreased EC/TC ratio in the plasma of hA-ITg SR-BI-/- mice is attributed to a reduction in LCAT reactivity with SM-enriched HDL particles.
|
|---|---|
| Authors | Ji-Young Lee, Robert M Badeau, Anny Mulya, Elena Boudyguina, Abraham K Gebre, Thomas L Smith, John S Parks |
| Journal | Journal of lipid research (J Lipid Res) Vol. 48 Issue 5 Pg. 1052-61 (May 2007) ISSN: 0022-2275 [Print] United States |
| PMID | 17272829 (Publication Type: Journal Article, Research Support, N.I.H., Extramural) |
| Chemical References |
|
| Topics |
|
Join CureHunter, for free Research Interface BASIC access!
Realize the full power of the drug-disease research graph!