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Updated: Jun 27, 2026
08:59
An Intestine/Liver Microphysiological System for Drug Pharmacokinetic and Toxicological Assessment
Published on: December 3, 2020
LXR-agonists regulate ApoM expression differentially in liver and intestine
Emine Calayir1, Tatjana M Becker, Adelheid Kratzer
1Institute of Molecular Biology and Biochemistry, Ctr. for Molecular Medicine, Medical University of Graz, Austria.
Current Pharmaceutical Biotechnology
|December 17, 2008
Summary
Liver X-receptor (LXR) agonists differentially regulate apolipoprotein M (apoM) expression. LXR activation downregulates apoM in the liver but upregulates it in the intestine, impacting cholesterol transport.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- Apolipoprotein M (apoM) is implicated in reverse cholesterol transport.
- The role of liver X-receptor (LXR) in apoM regulation is not fully understood.
- Understanding apoM's transcriptional regulation is crucial for metabolic research.
Purpose of the Study:
- To investigate the influence of liver X-receptor (LXR) agonists on apolipoprotein M (apoM) gene expression.
- To compare the effects of LXR agonists on apoM in different tissues (liver and intestine) and cell types (in vivo and in vitro).
Main Methods:
- Studies conducted in murine liver and intestinal mucosal cells in vivo.
- Experiments performed in human intestinal Caco-2 cells in vitro.
- Quantitative real-time PCR used to analyze apoM expression.
- Comparison of apoM expression with known LXR target genes like apoAI, Cyp7A1, and ABCA1.
Main Results:
- LXR agonist TO901317 downregulated hepatic apoM and apoAI expression by 40% and 60%, respectively, while upregulating Cyp7A1 by 280%.
- In the small intestine, TO901317 upregulated apoM and apoAI by 30-60% and ABCA1 by 250-430%.
- In Caco-2 cells, TO901317 and 22-hydroxycholesterol upregulated apoM by 60% and 40%, respectively.
Conclusions:
- Liver X-receptor (LXR) agonists exert differential effects on apolipoprotein M (apoM) gene expression in the liver versus the intestine.
- These tissue-specific regulatory differences may have implications for reverse cholesterol transport mechanisms.
- Further investigation is warranted to elucidate the precise mechanisms behind these differential effects.
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