title: Organization of fibroblasts in the heart.
abstract: Cardiac fibroblasts are organized into a three-dimensional network in the heart. This organization follows the endomysial weave network that surrounds groups of myocytes. Reverse transcriptase-polymerase chain reaction, Western blots, and immunohistochemistry were used to show that discoidin domain receptor 2 (DDR2) was specific for cardiac fibroblasts and not expressed on endothelial cells, smooth muscle cells, or cardiac myocytes. DDR2 is expressed early in development and in the adult heart. High voltage electron microscopy (HVEM), scanning electron microscopy, and laser scanning confocal microscopy document the three-dimensional organization of fibroblasts in the heart. Antibodies against connexin 43 and 45 showed different patterns but confirmed, along with HVEM, that fibroblasts are connected to each other as well as cardiac myocytes. The implications of this arrangement of fibroblasts can be important to cardiac function. The signaling of DDR2 and the expression of matrix metalloproteinase 2 in relation to collagen turnover and remodeling is discussed.
authors.affiliation: Department of Cell and Developmental Biology and Anatomy, University of South Carolina, Columbia, 29425, USA. ediegold@med.sc.edu
authors.forename: Edie C
authors.initials: EC
authors.lastname: Goldsmith
authors.forename: Adam
authors.initials: A
authors.lastname: Hoffman
authors.forename: Mary O
authors.initials: MO
authors.lastname: Morales
authors.forename: Jay D
authors.initials: JD
authors.lastname: Potts
authors.forename: Robert L
authors.initials: RL
authors.lastname: Price
authors.forename: Alex
authors.initials: A
authors.lastname: McFadden
authors.forename: Michael
authors.initials: M
authors.lastname: Rice
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Borg
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D018031:Connexin 43 / Q000378:metabolism; D017630:Connexins / Q000378:metabolism; D000070818:Discoidin Domain Receptors; D005109:Extracellular Matrix / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism* / Q000502:physiology*; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000166:cytology; D017434:Protein Structure, Tertiary; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D011975:Receptors, Mitogen / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012260:Ribonucleases / Q000378:metabolism; D013997:Time Factors
chemical_list: D018031:Connexin 43; D017630:Connexins; D011975:Receptors, Mitogen; C082920:connexin 45; D000070818:Discoidin Domain Receptors; D020794:Receptor Protein-Tyrosine Kinases; D012260:Ribonucleases