title: BRCA1 is a novel target to improve endothelial dysfunction and retard atherosclerosis.
abstract: OBJECTIVE
  BRCA1, a tumor suppressor gene implicated in breast and ovarian cancers, exerts multiple effects on DNA repair and affords resistance against cellular stress responses. We hypothesized that BRCA1 limits endothelial cell apoptosis and dysfunction, and via this mechanism attenuates atherosclerosis.
  
  
  METHODS
  Loss and gain of function were achieved in cultured endothelial cells by silencing and overexpressing BRCA1, respectively. In vivo loss and gain of function were performed by generating endothelial cell-specific knockout (EC-BRCA1(-/-)) mice and administering a BRCA1 adenovirus. Well-established cell and animal models of angiogenesis and atherosclerosis were used.
  
  
  RESULTS
  BRCA1 is basally expressed in endothelial cells. BRCA1 overexpression protected and BRCA1 silencing exaggerated inflammation- and doxorubicin-induced endothelial cell apoptosis. Key indices of endothelial function were modulated in a manner consistent with an effect of BRCA1 to limit endothelial cell apoptosis and improve endothelial function. BRCA1 overexpression strongly attenuated the production of reactive oxygen species and upregulated endothelial nitric oxide synthase, phosphorylated endothelial nitric oxide synthase, phosphorylated Akt, and vascular endothelial growth factor-a expression. BRCA1 overexpression also improved capillary density and promoted blood flow restoration in mice subjected to hind-limb ischemia. BRCA1-overexpressing ApoE(-/-) mice fed a Western diet developed significantly less aortic plaque lesions, exhibited reduced macrophage infiltration, and generated less reactive oxygen species. Lung sections and aortic segments from EC-BRCA1(-/-) mice demonstrated greater inflammation-associated apoptosis and impaired endothelial function, respectively. BRCA1 expression was attenuated in the plaque region of human atherosclerotic carotid artery samples compared with the adjacent plaque-free area.
  
  
  CONCLUSIONS
  These data collectively highlight a previously unrecognized role of BRCA1 as a gatekeeper of inflammation-induced endothelial cell function and a target to limit atherosclerosis. Translational studies evaluating endothelial function and atherosclerosis in individuals with BRCA1 mutations are suggested.
authors: Division of Cardiac Surgery, Li Ka Shing Knowledge Institute at St Michael's Hospital, Toronto, Ontario, Canada; Keenan Research Centre, Li Ka Shing Knowledge Institute at St Michael's Hospital, Toronto, Ontario, Canada.
authors: Krishna K
authors: KK
authors: Singh
authors: Praphulla C
authors: PC
authors: Shukla
authors: Adrian
authors: A
authors: Quan
authors: Mohammed
authors: M
authors: Al-Omran
authors: Fina
authors: F
authors: Lovren
authors: Yi
authors: Y
authors: Pan
authors: Christine
authors: C
authors: Brezden-Masley
authors: Alistair J
authors: AJ
authors: Ingram
authors: William L
authors: WL
authors: Stanford
authors: Hwee
authors: H
authors: Teoh
authors: Subodh
authors: S
authors: Verma
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D001057:Apolipoproteins E / Q000172:deficiency / Q000235:genetics; D017209:Apoptosis; D050197:Atherosclerosis / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D019313:BRCA1 Protein / Q000235:genetics / Q000378:metabolism*; D002340:Carotid Artery Diseases / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006614:Hindlimb; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism; D006801:Humans; D007511:Ischemia / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D018482:Muscle, Skeletal / Q000098:blood supply*; D018919:Neovascularization, Physiologic; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034622:RNA Interference; D017382:Reactive Oxygen Species / Q000378:metabolism; D020127:Recovery of Function; D012039:Regional Blood Flow; D013997:Time Factors; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D001057:Apolipoproteins E; D019313:BRCA1 Protein; C492913:BRCA1 protein, human; D017382:Reactive Oxygen Species; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; D051057:Proto-Oncogene Proteins c-akt
keywords: 29; 33.1; CMV; Dox; EC; ENOS; FITC; GAPDH; GFP; HUVEC; ICAM-1; MOI; PCR; PFU; ROS; SNP; TNFα; VCAM-1; VEGF; ad; adenovirus; cytomegalovirus; doxorubicin; endothelial cell; endothelial nitric oxide synthase; fluorescein isothiocyanate; glyceraldehyde 3-phosphate dehydrogenase; green fluorescent protein; human umbilical vein endothelial cell; intercellular adhesion molecule 1; multiplicity of infection; oxLDL; oxidized low-density lipoprotein; plaque-forming unit; polymerase chain reaction; reactive oxygen species; siRNA; single nucleotide polymorphism; small interfering RNA; tumor necrosis factor-alpha; vascular cell adhesion molecule 1; vascular endothelial growth factor