title: Fibronectin Splicing Variants Containing Extra Domain A Promote Atherosclerosis in Mice Through Toll-Like Receptor 4.
abstract: OBJECTIVE
  Cellular fibronectin containing extra domain A (EDA(+)-FN) is abundant in the arteries of patients with atherosclerosis. Several in vitro studies suggest that EDA(+)-FN interacts with Toll-like receptor 4 (TLR4). We tested the hypothesis that EDA(+)-FN exacerbates atherosclerosis through TLR4 in a clinically relevant model of atherosclerosis, the apolipoprotein E-deficient (Apoe(-/-)) mouse.
  
  
  RESULTS
  The extent of atherosclerosis was evaluated in whole aortae and cross sections of the aortic sinus in male and female EDA(-/-)Apoe(-/-) mice (which lack EDA(+)-FN), EDA(fl/fl)Apoe(-/-) mice (which constitutively express EDA(+)-FN), and control Apoe(-/-) mice fed a high-fat Western diet for 14 weeks. Irrespective of sex, EDA(fl/fl)Apoe(-/-) mice exhibited a 2-fold increase in atherosclerotic lesions (aorta and aortic sinus) and macrophage content within plaques, whereas EDA(-/-)Apoe(-/-) mice exhibited reduced atherosclerotic lesions (P<0.05 versus Apoe(-/-), n=10-12 mice/group), although cholesterol and triglyceride levels and circulating leukocytes were similar. Genetic ablation of TLR4 partially reversed atherosclerosis exacerbation in EDA(fl/fl)Apoe(-/-) mice (P<0.05) but had no effect on atherosclerotic lesions in EDA(-/-)Apoe(-/-) mice. Purified cellular FN, which contains EDA, potentiated dose-dependent NFκB-mediated inflammation (increased phospho-NFκB p65/NFκB p65, tumor necrosis factor-α, and interleukin-1β) in bone marrow-derived macrophages from EDA(-/-)Apoe(-/-) mice but not from EDA(-/-)TLR4(-/-)Apoe(-/-) mice. Finally, using immunohistochemistry, we provide evidence for the first time that EDA(+)-FN colocalizes with macrophage TLR4 in murine aortic lesions and human coronary artery atherosclerotic plaques.
  
  
  CONCLUSIONS
  Our findings reveal that TLR4 signaling contributes to EDA(+)-FN-mediated exacerbation of atherosclerosis. We suggest that EDA(+)-FN could be a therapeutic target in atherosclerosis.
authors.affiliation: From the Department of Internal Medicine (P.D., C.G., P.P., N.D., I.M.G., S.R.L., A.K.C.), and Department of Biology (M.E.D.), University of Iowa, Iowa City.
authors.forename: Prakash
authors.initials: P
authors.lastname: Doddapattar
authors.affiliation: From the Department of Internal Medicine (P.D., C.G., P.P., N.D., I.M.G., S.R.L., A.K.C.), and Department of Biology (M.E.D.), University of Iowa, Iowa City.
authors.forename: Chintan
authors.initials: C
authors.lastname: Gandhi
authors.affiliation: From the Department of Internal Medicine (P.D., C.G., P.P., N.D., I.M.G., S.R.L., A.K.C.), and Department of Biology (M.E.D.), University of Iowa, Iowa City.
authors.forename: Prem
authors.initials: P
authors.lastname: Prakash
authors.affiliation: From the Department of Internal Medicine (P.D., C.G., P.P., N.D., I.M.G., S.R.L., A.K.C.), and Department of Biology (M.E.D.), University of Iowa, Iowa City.
authors.forename: Nirav
authors.initials: N
authors.lastname: Dhanesha
authors.affiliation: From the Department of Internal Medicine (P.D., C.G., P.P., N.D., I.M.G., S.R.L., A.K.C.), and Department of Biology (M.E.D.), University of Iowa, Iowa City.
authors.forename: Isabella M
authors.initials: IM
authors.lastname: Grumbach
authors.affiliation: From the Department of Internal Medicine (P.D., C.G., P.P., N.D., I.M.G., S.R.L., A.K.C.), and Department of Biology (M.E.D.), University of Iowa, Iowa City.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Dailey
authors.affiliation: From the Department of Internal Medicine (P.D., C.G., P.P., N.D., I.M.G., S.R.L., A.K.C.), and Department of Biology (M.E.D.), University of Iowa, Iowa City.
authors.forename: Steven R
authors.initials: SR
authors.lastname: Lentz
authors.affiliation: From the Department of Internal Medicine (P.D., C.G., P.P., N.D., I.M.G., S.R.L., A.K.C.), and Department of Biology (M.E.D.), University of Iowa, Iowa City. anil-chauhan@uiowa.edu.
authors.forename: Anil K
authors.initials: AK
authors.lastname: Chauhan
mesh_terms: D000818:Animals; D001011:Aorta / Q000378:metabolism* / Q000473:pathology; D001018:Aortic Diseases / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000473:pathology / Q000517:prevention & control; D001057:Apolipoproteins E / Q000235:genetics / Q000378:metabolism; D050197:Atherosclerosis / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000473:pathology / Q000517:prevention & control; D003324:Coronary Artery Disease / Q000378:metabolism / Q000473:pathology; D003331:Coronary Vessels / Q000378:metabolism / Q000473:pathology; D059305:Diet, High-Fat; D004195:Disease Models, Animal; D005260:Female; D005353:Fibronectins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008077:Lipoproteins, LDL / Q000378:metabolism; D008264:Macrophages / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016328:NF-kappa B / Q000378:metabolism; D058226:Plaque, Atherosclerotic; D020033:Protein Isoforms; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D001057:Apolipoproteins E; D005353:Fibronectins; D008077:Lipoproteins, LDL; D016328:NF-kappa B; D020033:Protein Isoforms; C495345:TLR4 protein, human; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; C572454:extra domain A fibronectin, mouse
keywords: TLR4; apolipoprotein E; atherosclerosis; cellular fibronectin EDA; macrophages