Activation of FXR by obeticholic acid induces hepatic gene expression of SR-BI through a novel mechanism of transcriptional synergy with the nuclear receptor LXR

Dong,Bin; Singh,Amar   B.; Guo,Grace  L.; Young,Mark; Liu,Jingwen

doi:10.3892/ijmm.2019.4136

Activation of FXR by obeticholic acid induces hepatic gene expression of SR-BI through a novel mechanism of transcriptional synergy with the nuclear receptor LXR

Authors:
- Bin Dong
- Amar B. Singh
- Grace L. Guo
- Mark Young
- Jingwen Liu
View Affiliations

Affiliations: Department of Veterans Affairs, Palo Alto Health Care System, Palo Alto, CA 94304, USA, Department of Pharmacology and Toxicology, School of Pharmacy, Rutgers University, Piscataway, NJ 08854, USA, Mistral Therapeutics, San Diego, CA 92121, USA
Published online on: March 18, 2019 https://doi.org/10.3892/ijmm.2019.4136
Pages: 1927-1938
Copyright: © Dong et al. This is an open access article distributed under the terms of Creative Commons Attribution License.

Metrics: Total Views: 0 (Spandidos Publications: | PMC Statistics: )

Metrics: Total PDF Downloads: 0 (Spandidos Publications: | PMC Statistics: )

Cited By (CrossRef): 0 citations Loading Articles...

Abstract

The farnesoid X receptor (FXR) is known to regulate the gene expression of SR‑BI, which mediates plasma high‑density lipoprotein (HDL)‑cholesterol uptake. Our previous study demonstrated that the activation of FXR by obeticholic acid (OCA) lowered plasma HDL‑cholesterol levels and increased the hepatic mRNA and protein expression levels of SR‑BI in hypercholesterolemic hamsters, but not in normolipidemic hamsters, suggesting that dietary cholesterol may be involved in the OCA‑induced transcription of SR‑BI. In the present study, a functional 90‑base‑pair regulatory region was identified in the first intron of the SR‑BI gene of hamster and mouse that contains a FXR response element (IR‑1) and an adjacent liver X receptor (LXR) response element (LXRE). By in vitro DNA binding and luciferase reporter gene assays, it was demonstrated that FXR and LXR bind to their recognition sequences within this intronic region and transactivate the SR‑BI reporter gene in a synergistic manner. It was also shown that mutations at either the IR‑1 site or the LXRE site eliminated OCA‑mediated gene transcription. Utilizing chow‑fed hamsters as an in vivo model, it was demonstrated that treating normolipidemic hamsters with OCA or GW3965 alone did not effectively induce levels of SR‑BI, whereas their combined treatment significantly increased the mRNA and protein levels of SR‑BI in the liver. The study further investigated effects of FXR and LXR coactivation on the gene expression of SR‑BI in human liver cells. The intronic FXRE and LXRE regulatory region was not conserved in the human SR‑BI genomic sequence, however, higher mRNA expression levels of SR‑BI were observed in human primary hepatocytes and HepG2 cells exposed to combined treatments of FXR and LXR agonists, compared with those in cells exposed to individual ligand treatment. Therefore, these results suggest that human SR‑BI gene transcription may also be subject to concerted activation by FXR and LXR, mediated via currently unidentified regulatory sequences.

View Figures

View References

1	Forman BM, Goode E, Chen J, Oro AE, Bradley DJ, Perlmann T, Noonan DJ, Burka LT, McMorris T, Lamph WW, et al: Identification of a nuclear receptor that is activated by farnesol metabolites. Cell. 81:687–693. 1995. View Article : Google Scholar : PubMed/NCBI
2	Lefebvre P, Cariou B, Lien F, Kuipers F and Staels B: Role of bile acids and bile acid receptors in metabolic regulation. Physiol Rev. 89:147–191. 2009. View Article : Google Scholar : PubMed/NCBI
3	Sinal CJ, Tohkin M, Miyata M, Ward JM, Lambert G and Gonzalez FJ: Targeted disruption of the nuclear receptor FXR/BAR impairs bile acid and lipid homeostasis. Cell. 102:731–744. 2000. View Article : Google Scholar : PubMed/NCBI
4	Li G, Thomas AM, Williams JA, Kong B, Liu J, Inaba Y, Xie W and Guo GL: Farnesoid X receptor induces murine scavenger receptor Class B type I via intron binding. PLoS One. 7:e358952012. View Article : Google Scholar : PubMed/NCBI
5	Laffitte BA, Kast HR, Nguyen CM, Zavacki AM, Moore DD and Edwards PA: Identification of the DNA binding specificity and potential target genes for the farnesoid X-activated receptor. J Biol Chem. 275:10638–10647. 2000. View Article : Google Scholar : PubMed/NCBI
6	Calkin AC and Tontonoz P: Transcriptional integration of metabolism by the nuclear sterol-activated receptors LXR and FXR. Nat Rev Mol Cell Biol. 13:213–224. 2012. View Article : Google Scholar : PubMed/NCBI
7	Thomas AM, Hart SN, Kong B, Fang J, Zhong XB and Guo GL: Genome-wide tissue-specific farnesoid X receptor binding in mouse liver and intestine. Hepatology. 51:1410–1419. 2010. View Article : Google Scholar : PubMed/NCBI
8	Zhan L, Liu HX, Fang Y, Kong B, He Y, Zhong XB, Fang J, Wan YJ and Guo GL: Genome-wide binding and transcriptome analysis of human farnesoid X receptor in primary human hepatocytes. PLoS One. 9:e1059302014. View Article : Google Scholar : PubMed/NCBI
9	Acton S, Rigotti A, Landschulz KT, Xu S, Hobbs HH and Krieger M: Identification of scavenger receptor SR-BI as a high density lipoprotein receptor. Science. 271:518–520. 1996. View Article : Google Scholar : PubMed/NCBI
10	Rigotti A, Trigatti BL, Penman M, Rayburn H, Herz J and Krieger M: A targeted mutation in the murine gene encoding the high density lipoprotein (HDL) receptor scavenger receptor class B type I reveals its key role in HDL metabolism. Proc Natl Acad Sci USA. 94:12610–12615. 1997. View Article : Google Scholar : PubMed/NCBI
11	Brodeur MR, Luangrath V, Bourret G, Falstrault L and Brissette L: Physiological importance of SR-BI in the in vivo metabolism of human HDL and LDL in male and female mice. J Lipid Res. 46:687–696. 2005. View Article : Google Scholar : PubMed/NCBI
12	Zanoni P, Khetarpal SA, Larach DB, Hancock-Cerutti WF, Millar JS, Cuchel M, DerOhannessian S, Kontush A, Surendran A, Saleheen D, et al: Rare variant in scavenger receptor BI raises HDL cholesterol and increases risk of coronary heart disease. Science. 351:1166–1171. 2016. View Article : Google Scholar : PubMed/NCBI
13	Rizzo G, Passeri D, De Franco F, Ciaccioli G, Donadio L, Orlandi S, Sadeghpour B, Wang XX, Jiang T, Levi M, et al: Functional characterization of the semisynthetic bile acid derivative INT-767, a dual farnesoid X receptor and TGR5 agonist. Mol Pharmacol. 78:617–630. 2010. View Article : Google Scholar : PubMed/NCBI
14	Hambruch E, Miyazaki-Anzai S, Hahn U, Matysik S, Boettcher A, Perović-Ottstadt S, Schlüter T, Kinzel O, Krol HD, Deuschle U, et al: Synthetic farnesoid X receptor agonists induce high-density lipoprotein-mediated transhepatic cholesterol efflux in mice and monkeys and prevent atherosclerosis in cholesteryl ester transfer protein transgenic low-density lipoprotein receptor (-/-) mice. J Pharmacol Exp Ther. 343:556–567. 2012. View Article : Google Scholar : PubMed/NCBI
15	Zhang Y, Yin L, Anderson J, Ma H, Gonzalez FJ, Willson TM and Edwards PA: Identification of novel pathways that control farnesoid X receptor-mediated hypocholesterolemia. J Biol Chem. 285:3035–3043. 2010. View Article : Google Scholar :
16	Chong HK, Infante AM, Seo YK, Jeon TI, Zhang Y, Edwards PA, Xie X and Osborne TF: Genome-wide interrogation of hepatic FXR reveals an asymmetric IR-1 motif and synergy with LRH-1. Nucleic Acids Res. 38:6007–6017. 2010. View Article : Google Scholar : PubMed/NCBI
17	Chao F, Gong W, Zheng Y, Li Y, Huang G, Gao M, Li J, Kuruba R, Gao X, Li S and He F: Upregulation of scavenger receptor class B type I expression by activation of FXR in hepatocyte. Atherosclerosis. 213:443–448. 2010. View Article : Google Scholar : PubMed/NCBI
18	Dong B, Young M, Liu X, Singh AB and Liu J: Regulation of lipid metabolism by obeticholic acid in hyperlipidemic hamsters. J Lipid Res. 58:350–363. 2017. View Article : Google Scholar :
19	Repa JJ and Mangelsdorf DJ: The role of orphan nuclear receptors in the regulation of cholesterol homeostasis. Annu Rev Cell Dev Biol. 16:459–481. 2000. View Article : Google Scholar : PubMed/NCBI
20	Apfel R, Benbrook D, Lernhardt E, Ortiz MA, Salbert G and Pfahl M: A novel orphan receptor specific for a subset of thyroid hormone-responsive elements and its interaction with the retinoid/thyroid hormone receptor subfamily. Mol Cell Biol. 14:7025–7035. 1994. View Article : Google Scholar : PubMed/NCBI
21	Jakobsson T, Treuter E, Gustafsson JA and Steffensen KR: Liver X receptor biology and pharmacology: New pathways, challenges and opportunities. Trends Pharmacol Sci. 33:394–404. 2012. View Article : Google Scholar : PubMed/NCBI
22	Maxwell KN, Soccio RE, Duncan EM, Sehayek E and Reslow JL: Novel putative SREBP and LXR target genes identified by micro-array analysis in liver of cholesterol-fed mice. J Lipid Res. 44:2109–2119. 2003. View Article : Google Scholar : PubMed/NCBI
23	Grefhorst A, Oosterveer MH, Brufau G, Boesjes M, Kuipers F and Groen AK: Pharmacological LXR activation reduces presence of SR-B1 in liver membranes contributing to LXR-mediated induction of HDL-cholesterol. Atherosclerosis. 222:382–389. 2012. View Article : Google Scholar : PubMed/NCBI
24	Cartharius K, Frech K, Grote K, Klocke B, Haltmeier M, Klingenhoff A, Frisch M, Bayerlein M and Werner T: MatInspector and beyond: Promoter analysis based on transcription factor binding sites. Bioinformatics. 21:2933–2942. 2005. View Article : Google Scholar : PubMed/NCBI
25	Cartharius K: MatInspector: Analysing Promoters for Transcription Factor Binding Sites. The Nuts & Bolts Series. DNA Press. 2005.
26	Quandt K, Frech K, Karas H, Wingender E and Werner T: MatInd and MatInspector: New fast and versatile tools for detection of consensus matches in nucleotide sequence data. Nucleic Acids Res. 23:4878–4884. 1995. View Article : Google Scholar : PubMed/NCBI
27	Li H, Dong B, Park SW, Lee HS, Chen W and Liu J: Hepatocyte nuclear factor 1alpha plays a critical role in PCSK9 gene transcription and regulation by the natural hypocholesterolemic compound berberine. J Biol Chem. 284:28885–28895. 2009. View Article : Google Scholar : PubMed/NCBI
28	Livak KJ and Schmittgen TD: Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C(T)) method. Methods. 25:402–408. 2001. View Article : Google Scholar
29	Malerød L, Juvet LK, Hanssen-Bauer A, Eskild W and Berg T: Oxysterol-activated LXRalpha/RXR induces hSR-BI-promoter activity in hepatoma cells and preadipocytes. Biochem Biophys Res Commun. 299:916–923. 2002. View Article : Google Scholar : PubMed/NCBI
30	Dong B, Kan CF, Singh AB and Liu J: High-fructose diet down-regulates long-chain acyl-CoA synthetase 3 expression in liver of hamsters via impairing LXR/RXR signaling pathway. J Lipid Res. 54:1241–1254. 2013. View Article : Google Scholar : PubMed/NCBI
31	Schuetz EG, Strom S, Yasuda K, Lecureur V, Assem M, Brimer C, Lamba J, Kim RB, Ramachandran V, Komoroski BJ, et al: Disrupted bile acid homeostasis reveals an unexpected interaction among nuclear hormone receptors, transporters, and cytochrome P450. J Biol Chem. 276:39411–39418. 2001. View Article : Google Scholar : PubMed/NCBI
32	Schultz JR, Tu H, Luk A, Repa JJ, Medina JC, Li L, Schwendner S, Wang S, Thoolen M, Mangelsdorf DJ, et al: Role of LXRs in control of lipogenesis. Genes Dev. 14:2831–2838. 2000. View Article : Google Scholar : PubMed/NCBI
33	Ding L, Pang S, Sun Y, Tian Y, Yu L and Dang N: Coordinated actions of FXR and LXR in metabolism: From pathogenesis to pharmacological targets for type 2 diabetes. Int J Endocrinol. 2014:7518592014. View Article : Google Scholar : PubMed/NCBI
34	Lu TT, Makishima M, Repa JJ, Schoonjans K, Kerr TA, Auwerx J and Mangelsdorf DJ: Molecular basis for feedback regulation of bile acid synthesis by nuclear receptors. Mol Cell. 6:507–515. 2000. View Article : Google Scholar : PubMed/NCBI
35	Matsukuma KE, Bennett MK, Huang J, Wang L, Gil G and Osborne TF: Coordinated control of bile acids and lipogenesis through FXR-dependent regulation of fatty acid synthase. J Lipid Res. 47:2754–2761. 2006. View Article : Google Scholar : PubMed/NCBI
36	Peet DJ, Turley SD, Ma W, Janowski BA, Lobaccaro JM, Hammer RE and Mangelsdorf DJ: Cholesterol and bile acid metabolism are impaired in mice lacking the nuclear oxysterol receptor LXR alpha. Cell. 93:693–704. 1998. View Article : Google Scholar : PubMed/NCBI
37	Malerød L, Sporstøl M, Juvet LK, Mousavi A, Gjøen T and Berg T: Hepatic scavenger receptor class B, type I is stimulated by peroxisome proliferator-activated receptor gamma and hepatocyte nuclear factor 4alpha. Biochem Biophys Res Commun. 305:557–565. 2003. View Article : Google Scholar : PubMed/NCBI
38	Schoonjans K, Annicotte JS, Huby T, Botrugno OA, Fayard E, Ueda Y, Chapman J and Auwerx J: Liver receptor homolog 1 controls the expression of the scavenger receptor class B type I. EMBO Rep. 3:1181–1187. 2002. View Article : Google Scholar : PubMed/NCBI