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Updated: Apr 19, 2026
A Phenotyping Regimen for Genetically Modified Mice Used to Study Genes Implicated in Human Diseases of Aging
Published on: July 14, 2016
HDL from apoA1 transgenic mice expressing the 4WF isoform is resistant to oxidative loss of function
Stela Z Berisha1, Greg Brubaker1, Takhar Kasumov2
1Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195.
Abstract:
HDL functions are impaired by myeloperoxidase (MPO), which selectively targets and oxidizes human apoA1. We previously found that the 4WF isoform of human apoA1, in which the four tryptophan residues are substituted with phenylalanine, is resistant to MPO-mediated loss of function. The purpose of this study was to generate 4WF apoA1 transgenic mice and compare functional properties of the 4WF and wild-type human apoA1 isoforms in vivo. Male mice had significantly higher plasma apoA1 levels than females for both isoforms of human apoA1, attributed to different production rates. With matched plasma apoA1 levels, 4WF transgenics had a trend for slightly less HDL-cholesterol versus human apoA1 transgenics. While 4WF transgenics had 31% less reverse cholesterol transport (RCT) to the plasma compartment, equivalent RCT to the liver and feces was observed. Plasma from both strains had similar ability to accept cholesterol and facilitate ex vivo cholesterol efflux from macrophages. Furthermore, we observed that 4WF transgenic HDL was partially (∼50%) protected from MPO-mediated loss of function while human apoA1 transgenic HDL lost all ABCA1-dependent cholesterol acceptor activity. In conclusion, the structure and function of HDL from 4WF transgenic mice was not different than HDL derived from human apoA1 transgenic mice.
Insights
This study explored a modified human apolipoprotein A1 (apoA1) protein in mice. The 4WF apoA1 isoform showed partial protection against myeloperoxidase (MPO) damage, suggesting a potential therapeutic target for HDL dysfunction.
Area of Science:
- Biochemistry
- Cardiovascular Science
- Genetics
Background:
- High-density lipoprotein (HDL) function is crucial for cholesterol homeostasis.
- Myeloperoxidase (MPO) impairs HDL function by oxidizing apolipoprotein A1 (apoA1).
- A modified apoA1 (4WF isoform) shows resistance to MPO-mediated oxidation in vitro.
Purpose of the Study:
- To generate 4WF apoA1 transgenic mice.
- To compare the in vivo functional properties of 4WF apoA1 and wild-type human apoA1.
Main Methods:
- Generation of 4WF apoA1 and wild-type human apoA1 transgenic mice.
- Measurement of plasma apoA1 levels, HDL-cholesterol, and reverse cholesterol transport (RCT).
- Assessment of cholesterol efflux from macrophages and HDL protection against MPO in vitro.
Main Results:
- Male mice exhibited higher plasma apoA1 levels than females for both isoforms.
- 4WF transgenics showed a trend for less HDL-cholesterol and reduced RCT to plasma but equivalent RCT to liver/feces.
- 4WF transgenic HDL was partially protected from MPO-mediated loss of function compared to wild-type human apoA1 transgenic HDL.
Conclusions:
- The 4WF apoA1 isoform offers partial protection against MPO-mediated HDL dysfunction in vivo.
- While some functional differences were observed, overall HDL structure and function in 4WF mice were comparable to wild-type human apoA1 mice.
- This suggests the 4WF apoA1 isoform may be a valuable tool for studying HDL protection strategies.
