The bile acid sensor FXR protects against dyslipidemia and aortic plaques development induced by the HIV protease inhibitor ritonavir in mice.
BACKGROUND
Although human immunodeficiency virus (HIV)-related morbidity and mortality rates in patients treated with a combination of high active antiretroviral therapy (HAART) have declined, significant metabolic/vascular adverse effects associated with the long term use of HIV protease inhibitors (PIs) have emerged as a significant side effect. Here we illustrate that targeting the bile acid sensor farnesoid X receptor (FXR) protects against dyslipidemia and vascular injury induced HIV-PIs in rodents.


RESULTS
Administration of the HIV PI ritonavir to wild type mice increased plasma triacylglycerols and cholesterol levels and this effect was exacerbated by dosing ritonavir to mice harbouring a disrupted FXR. Dyslipidemia induced by ritonavir associated with a shift in the liver expression of signature genes, Sterol Regulatory Element-Binding Protein (SREBP)-1 and fatty acid synthase. Treating wild type mice with the FXR agonist (chenodeoxycholic acid, CDCA) protected against development of dyslipidemia induced by ritonavir. Administration of ritonavir to ApoE(-/-) mice, a strain that develop spontaneously atherosclerosis, increased the extent of aortic plaques without worsening the dyslipidemia. Treating these mice with CDCA reduced the extent of aortic plaques by 70% without changing plasma lipoproteins or the liver expression of signature genes. A beneficial effect on aortic plaques was also obtained by treating ApoE(-/-) mice with gemfibrozil, a PPARα agonist. FXR activation counter-regulated induction of expression/activity of CD36 caused by HIV-PIs in circulating monocytes and aortic plaques. In macrophages cell lines, CDCA attenuated CD36 induction and uptake of acetylated LDL caused by ritonavir. Natural and synthetic FXR ligands reduced the nuclear translocation of SREBP1c caused by ritonavir.


CONCLUSIONS
Activation of the bile acid sensor FXR protects against dyslipidemia and atherosclerotic caused by ritonavir, a widely used HIV PI. From a mechanistic stand point it appears that besides reducing the liver expression of genes involved in fatty acid synthesis, FXR activation counter-regulates the expression/activity of CD36 on monocytes. FXR ligands might hold promise in the treatment dyslipidemia induced by ritonavir.
Dipartimento di Medicina Clinica e Sperimentale, University of Perugia, Facoltà di Medicina e Chirurgia, Perugia, Italy.
Andrea
A
Mencarelli
Sabrina
S
Cipriani
Barbara
B
Renga
Daniela
D
Francisci
Giuseppe
G
Palladino
Eleonora
E
Distrutti
Franco
F
Baldelli
Stefano
S
Fiorucci
D000818:Animals; D001011:Aorta / Q000473:pathology*; D001057:Apolipoproteins E / Q000235:genetics / Q000502:physiology; D050197:Atherosclerosis / Q000517:prevention & control*; D001647:Bile Acids and Salts / Q000378:metabolism*; D018955:CD36 Antigens / Q000378:metabolism; D002460:Cell Line; D050171:Dyslipidemias / Q000517:prevention & control*; D017320:HIV Protease Inhibitors / Q000009:adverse effects*; D051379:Mice; D018345:Mice, Knockout; D018160:Receptors, Cytoplasmic and Nuclear / Q000502:physiology*; D019438:Ritonavir / Q000009:adverse effects*; D000099150:Receptor, Farnesoid X-Activated
D001057:Apolipoproteins E; D001647:Bile Acids and Salts; D018955:CD36 Antigens; D017320:HIV Protease Inhibitors; D018160:Receptors, Cytoplasmic and Nuclear; D019438:Ritonavir; D000099150:Receptor, Farnesoid X-Activated