Adenosine receptors: Modulators of lipid availability that are controlled by lipid levels.
Adenosine as well as agonists and antagonists for the four adenosine receptor subtypes (A1R, A2AR, A2BR and A3R) play a role in several key physiological and pathophysiological processes, including the regulation of vascular tone, thrombosis, immune response, inflammation, and angiogenesis. This review focuses on the adenosine-mediated regulation of lipid availability in the cell and in the systemic circulation as well in humans and animal models. Therefore, adenosine, mainly by acting on A1R, inhibits lipolysis activity, leading to reduction of the circulating fatty acid levels. This nucleoside can also participate in the early development of atherosclerosis by inhibiting the formation of foam cells via stimulation of cholesterol efflux through A2AR expressed on macrophages and reduction of the inflammatory process by activating A2AR and A2BR. Adenosine also appears to modulate intracellular cholesterol availability in Niemann-Pick type C1 disease and Alzheimer disease via A2AR and A3, respectively. Remarkably, the role of adenosine receptors in the regulation of plasma total cholesterol and triglyceride levels has been studied in animal models. Thus, an anti-atherogenic role for A2BR as well as a pro-atherogenic role of A2AR and A1 have been proposed; A3R has not been shown to participate in the control of lipid levels or the development of atherosclerosis. Surprisingly, and despite the role of A2A in the inhibition of foam cell formation among isolated cells, this receptor appears to be pro-atherogenic in mice. Remarkably, the role of adenosine receptors in human dyslipidaemia and atherosclerosis must to be elucidated. Additionally, it has been reported that increased lipid levels impair the effects of adenosine/adenosine receptors in controlling vascular tone, and we speculate on the possibility that this impairment could be due to alterations in the composition of the membrane microdomains where the adenosine receptors are located. Finally, a possible role for adenosine/adenosine receptors in the phenomena of dyslipidaemia in pregnancy has been proposed.
Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile. Electronic address: aaleiva@uc.cl.
Andrea
A
Leiva
School of Medical Technology, Health Sciences Faculty, Universidad San Sebastian, Lientur 1457, Concepción 4080871, Chile.
Enrique
E
Guzmán-Gutiérrez
Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile.
Susana
S
Contreras-Duarte
Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile.
Bárbara
B
Fuenzalida
Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile.
Claudette
C
Cantin
Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile.
Lorena
L
Carvajal
Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville E-41012, Spain.
Rocío
R
Salsoso
Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Cellular Signaling and Differentiation Laboratory (CSDL), School of Medical Technology, Health Sciences Faculty, Universidad San Sebastian, Santiago 7510157, Chile.
Jaime
J
Gutiérrez
Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Metabolic Diseases Research Laboratory (MDRL), Center of Research, Development and Innovation in Health - Aconcagua Valley, San Felipe Campus, School of Medicine, Faculty of Medicine, Universidad de Valparaiso, San Felipe 2172972, Chile.
Fabián
F
Pardo
Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville E-41012, Spain; University of Queensland Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston, QLD 4029, Queensland, Australia.
Luis
L
Sobrevia
D000241:Adenosine / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport / Q000235:genetics; D002784:Cholesterol / Q000378:metabolism*; D006801:Humans; D050356:Lipid Metabolism; D018047:Receptors, Purinergic P1 / Q000235:genetics / Q000378:metabolism*
D018047:Receptors, Purinergic P1; D002784:Cholesterol; D000241:Adenosine
Adenosine; Atherosclerosis; Cholesterol; Pregnancy; Triglycerides