title: Inhibition of autophagy inhibits the conversion of cardiac fibroblasts to cardiac myofibroblasts.
abstract: The incidence of heart failure with concomitant cardiac fibrosis is very high in developed countries. Fibroblast activation in heart is causal to cardiac fibrosis as they convert to hypersynthetic cardiac myofibroblasts. There is no known treatment for cardiac fibrosis. Myofibroblasts contribute to the inappropriate remodeling of the myocardial interstitium, which leads to reduced cardiac function and ultimately heart failure. Elevated levels of autophagy have been linked to stress-induced ventricular remodeling and other cardiac diseases. Previously, we had shown that TGF-β1 treatment of human atrial fibroblasts both induced autophagy and enhanced the fibrogenic response supporting a linkage between the myofibroblast phenotype and autophagy. We now demonstrate that with in vitro culture of primary rat cardiac fibroblasts, inhibition of autophagy represses fibroblast to myofibroblast phenoconversion. Culturing unpassaged cardiac fibroblasts for 72 hours on plastic tissue culture plates is associated with elevated α-smooth muscle actin (α-SMA) expression. This activation parallels increased microtubule-associated protein 1A/1B-light chain 3 (LC-3β II) protein expression. Inhibition of autophagy with bafilomycin-A1 (Baf-A1) and chloroquine (CQ) in cardiac fibroblasts significantly reduces α-SMA and extracellular domain A fibronectin (ED-A FN) protein vs untreated controls. Myofibroblast cell migration and contractility were significantly reduced following inhibition of autophagy. These data support the possibility of a causal link between cardiac fibroblast-to-myofibroblast phenoconversion and autophagy.
authors.affiliation: Department of Physiology and Pathophysiology, Institute of Cardiovascular Sciences, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Shivika S
authors.initials: SS
authors.lastname: Gupta
authors.affiliation: Department of Physiology and Pathophysiology, Institute of Cardiovascular Sciences, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Zeglinski
authors.affiliation: Department of Physiology and Pathophysiology, Institute of Cardiovascular Sciences, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Sunil G
authors.initials: SG
authors.lastname: Rattan
authors.affiliation: Department of Physiology and Pathophysiology, Institute of Cardiovascular Sciences, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Natalie M
authors.initials: NM
authors.lastname: Landry
authors.affiliation: Department of Human Anatomy and Cell Science, Basic Medical Sciences Building, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.|Children's Hospital Research Institute of Manitoba, John Buhler Research Centre, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Saeid
authors.initials: S
authors.lastname: Ghavami
authors.affiliation: Department of Biochemistry and Medical Genetics, Institute of Cardiovascular Sciences, Rady Faculty of Health Sciences, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Wigle
authors.affiliation: Department of Human Anatomy and Cell Science, Basic Medical Sciences Building, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Thomas
authors.initials: T
authors.lastname: Klonisch
authors.affiliation: Children's Hospital Research Institute of Manitoba, John Buhler Research Centre, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.|Department of Physiology and Pathophysiology, Internal Medicine and Pediatrics and Child Health, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Halayko
authors.affiliation: Department of Physiology and Pathophysiology, Institute of Cardiovascular Sciences, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Ian M C
authors.initials: IM
authors.lastname: Dixon
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001343:Autophagy / Q000187:drug effects*; D009202:Cardiomyopathies / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D002738:Chloroquine / Q000494:pharmacology*; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005353:Fibronectins / Q000378:metabolism; D005355:Fibrosis; D018942:Macrolides / Q000494:pharmacology*; D008297:Male; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism / Q000473:pathology*; D058628:Myofibroblasts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D010641:Phenotype; D010766:Phosphorylation; D061251:Primary Cell Culture; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D000199:Actins; D002738:Chloroquine; D005353:Fibronectins; D018942:Macrolides; D008869:Microtubule-Associated Proteins; D048051:p38 Mitogen-Activated Protein Kinases; C526109:Anxa3 protein, rat; C498862:Acta2 protein, rat; C040929:bafilomycin A1
keywords: autophagy; cardiac fibroblast; cardiac fibrosis; myofibroblast; phenoconversion