title: Glucagon-like peptide 1 (GLP-1)-based therapy upregulates LXR-ABCA1/ABCG1 cascade in adipocytes.
abstract: A promising treatment for obesity involves the use of therapeutic agents that increase the level of the glucagon-like peptide (GLP-1) which reduces appetite and food intake. Native GLP-1 is rapidly metabolized by the dipeptidyl peptidase-4 (DPP-4) enzyme and, as such, GLP-1 mimetics or DPP-4 inhibitors represent promising treatment approaches. Interestingly, obese patient receiving such medications showed improved lipid profiles and cholesterol homeostasis, however the mechanism(s) involved are not known. Members of the ATP-binding cassette (ABC) transporters, including ABCA1 and ABCG1, play essential roles in reverse cholesterol transport and in high density lipoprotein (HDL) formation. These transporters are under the transcriptional regulation of liver X receptor alpha (LXR-α). We hypothesize that GLP-1 mimetics and/or DPP-4 inhibitors modulate ABCA1/ABCG1 expression in adipocytes through an LXR-α mediated process and thus affecting cholesterol homeostasis. 3T3-L1 adipocytes were treated with the DPP-4 inhibitor vildagliptin (2 nM) or the GLP-1 mimetic exendin-4 (5 nM). Gene and protein expression of ABCA1, ABCG1 and LXR-α were determined and correlated with cholesterol efflux. Expression levels of interleukin-6 (IL-6), leptin and the glucose transporter-4 (GLUT-4) were also determined. Treatment with both medications significantly increased the expression of ABCA1, ABCG1, LXR-α and GLUT-4, decreased IL-6 and leptin, and improved cholesterol efflux from adipocytes (P < 0.05). Our data suggest that GLP-1-based therapy modulate ABCA1/ABCG1 expression in adipocytes potentially through an LXR-α mediated process.
authors.affiliation: Department of Obstetrics and Gynecology, The University of Texas Medical Branch, Galveston, TX, USA; Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt.
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Mostafa
authors.affiliation: Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt.
authors.forename: Nadia M
authors.initials: NM
authors.lastname: Hamdy
authors.affiliation: Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt.
authors.forename: Hala O
authors.initials: HO
authors.lastname: El-Mesallamy
authors.affiliation: Department of Obstetrics and Gynecology, The University of Texas Medical Branch, Galveston, TX, USA. Electronic address: sabdelra@utmb.edu.
authors.forename: Sherif Z
authors.initials: SZ
authors.lastname: Abdel-Rahman
mesh_terms: D016475:3T3 Cells; D064286:ATP Binding Cassette Transporter 1 / Q000378:metabolism*; D000070998:ATP Binding Cassette Transporter, Subfamily G, Member 1; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D019440:Anti-Obesity Agents / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D052216:Glucagon-Like Peptide 1 / Q000008:administration & dosage*; D054795:Incretins / Q000008:administration & dosage; D008074:Lipoproteins / Q000378:metabolism*; D000071518:Liver X Receptors; D051379:Mice; D057093:Orphan Nuclear Receptors / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology*
chemical_list: D064286:ATP Binding Cassette Transporter 1; D000070998:ATP Binding Cassette Transporter, Subfamily G, Member 1; D018528:ATP-Binding Cassette Transporters; D019440:Anti-Obesity Agents; D052216:Glucagon-Like Peptide 1; D054795:Incretins; D008074:Lipoproteins; D000071518:Liver X Receptors; D057093:Orphan Nuclear Receptors; C577833:Abca1 protein, mouse; C487540:ABCG1 protein, mouse; C000605214:Nr1h3 protein, mouse
keywords: ABC transporters; Adipocytes; Cholesterol; DPP-4 inhibitor; GLP-1