Miguel Hueso1, Raquel Griñán2, Adrián Mallen3, Estanislao Navarro3, Elvira Purqueras4, Montse Gomá4, Fabrizio Sbraga5, Arnau Blasco-Lucas5, Giovanna Revilla6, David Santos7, Marina Canyelles6, Josep Julve8, Joan Carles Escolà-Gil9, Noemi Rotllan10. 1. Department of Nephrology, Hospital Universitari Bellvitge and Bellvitge Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08907 Barcelona, Spain; Nephrology and Renal Transplantation Group, Infectious Disease and Transplantation Program, Institut d'Investigació Biomèdica de Bellvitge-IDIBELL, L'Hospitalet de Llobregat, 08907 Barcelona, Spain. Electronic address: mhueso@idibell.cat. 2. Institut d'Investigacions Biomèdiques (IIB) Sant Pau, C/ Sant Quintí 77, 08041 Barcelona, Spain; Departament de Bioquímica i Biologia Molecular, Universitat Autònoma De Barcelonna, 08041 Barcelona, Spain. 3. Nephrology and Renal Transplantation Group, Infectious Disease and Transplantation Program, Institut d'Investigació Biomèdica de Bellvitge-IDIBELL, L'Hospitalet de Llobregat, 08907 Barcelona, Spain. 4. Department of Pathology, Hospital Universitari Bellvitge and Bellvitge Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08907 Barcelona, Spain. 5. Department of Cardiac Surgery, Hospital Universitari Bellvitge and Bellvitge Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08907 Barcelona, Spain. 6. Institut d'Investigacions Biomèdiques (IIB) Sant Pau, C/ Sant Quintí 77, 08041 Barcelona, Spain. 7. CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain. 8. Institut d'Investigacions Biomèdiques (IIB) Sant Pau, C/ Sant Quintí 77, 08041 Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain. 9. Institut d'Investigacions Biomèdiques (IIB) Sant Pau, C/ Sant Quintí 77, 08041 Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain. Electronic address: JEscola@santpau.cat. 10. Institut d'Investigacions Biomèdiques (IIB) Sant Pau, C/ Sant Quintí 77, 08041 Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain. Electronic address: nrotllanv@santpau.cat.
Abstract
OBJECTIVE: To determine whether miR-125b regulates cholesterol efflux in vivo and in vitro through the regulation of scavenger receptor type B1 (SR-B1). APPROACH AND RESULTS: We demonstrated that miR-125b is up-regulated in the human aortas of patients with CAD and is located in macrophages and vascular smooth muscle cells (VSMCs). We identified SCARB1 as a direct target of miR-125b by repressing the activity of the SCARB1 3'-untranslated region reporter construct. Moreover, the overexpression of miR-125b in both human and mouse macrophages as well as VSMCs was found to downregulated the expression of the SCARB1 and the SR-B1 protein levels, thereby impairing α-HDL-mediated macrophage cholesterol efflux in vitro. The in vivo reverse cholesterol transport (RCT) rate from non-cholesterol-loaded macrophages transfected with miR-125b to feces was also found to be decreased when compared with that of control mimic-transfected macrophages. CONCLUSIONS: Together, these results provide evidence that miR-125b downregulates SCARB1 and SR-B1 in both human and mouse macrophages as well as VSMCs, thereby impairing macrophage cholesterol efflux in vitro and the whole macrophage-specific RCT pathway in vivo.
OBJECTIVE: To determine whether miR-125b regulates cholesterol efflux in vivo and in vitro through the regulation of scavenger receptor type B1 (SR-B1). APPROACH AND RESULTS: We demonstrated that miR-125b is up-regulated in the human aortas of patients with CAD and is located in macrophages and vascular smooth muscle cells (VSMCs). We identified SCARB1 as a direct target of miR-125b by repressing the activity of the SCARB1 3'-untranslated region reporter construct. Moreover, the overexpression of miR-125b in both human and mouse macrophages as well as VSMCs was found to downregulated the expression of the SCARB1 and the SR-B1 protein levels, thereby impairing α-HDL-mediated macrophage cholesterol efflux in vitro. The in vivo reverse cholesterol transport (RCT) rate from non-cholesterol-loaded macrophages transfected with miR-125b to feces was also found to be decreased when compared with that of control mimic-transfected macrophages. CONCLUSIONS: Together, these results provide evidence that miR-125b downregulates SCARB1 and SR-B1 in both human and mouse macrophages as well as VSMCs, thereby impairing macrophage cholesterol efflux in vitro and the whole macrophage-specific RCT pathway in vivo.