title: Spatially and temporally different expression of osteonectin and osteopontin in the infarct zone of experimentally induced myocardial infarction in rats.
abstract: Osteonectin and osteopontin, two secreted matricellular proteins, have a variety of functions that are exerted through interaction with matrix components. These proteins appear in response to tissue injury. To test our hypothesis that osteopontin and osteonectin are expressed with spatially and temporally different patterns in myocardial infarct tissue, we investigated osteonectin and osteopontin expression in experimentally induced myocardial infarction in rats, in comparison with Type I collagen expression. Northern blotting demonstrated that osteonectin mRNA did not markedly increase on Day 2 after the infarction, but it increased on Days 7 and 14 by 1.7+/-0.12- and 1.8+/-0.01-fold compared to that in preligation hearts. In contrast, osteopontin mRNA was increased on Day 1 (41.9+/-11.3-fold increase) and on Day 2 (58.3+/-7.6-fold increase), and then it declined on Days 7 and 14 (24.8+/-9.0- and 13.5+/-4.7-fold increase, respectively). In situ hybridization revealed that osteonectin mRNA signals were observed in fibroblasts, myofibroblasts and macrophages around infarct necrotic tissue on Days 7 and 14. Osteopontin mRNA signals were observed in macrophages in the infarct marginal zone on Day 2. Immunopositive staining for both osteonectin and osteopontin showed the same pattern as that obtained by in situ hybridization. The time course of osteonectin mRNA was almost parallel with that of Type I collagen mRNA, while that of osteopontin was not. These results demonstrated spatially and temporally different expression patterns of osteonectin and osteopontin in myocardial infarction and suggest that osteonectin appears to be involved in the pathological course in the late phase after infarction concomitantly with Type I collagen, while osteopontin may play a role in the early phase.
authors.affiliation: Department of Medicine and Medical Science, Okayama University Graduate School of Medicine and Dentistry, Okayama 700-8558, Japan.
authors.forename: Issei
authors.initials: I
authors.lastname: Komatsubara
authors.forename: Takashi
authors.initials: T
authors.lastname: Murakami
authors.forename: Shozo
authors.initials: S
authors.lastname: Kusachi
authors.forename: Keigo
authors.initials: K
authors.lastname: Nakamura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hirohata
authors.forename: Junichi
authors.initials: J
authors.lastname: Hayashi
authors.forename: Shunji
authors.initials: S
authors.lastname: Takemoto
authors.forename: Chisato
authors.initials: C
authors.lastname: Suezawa
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Ninomiya
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Shiratori
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D015870:Gene Expression; D007124:Immunoenzyme Techniques; D017403:In Situ Hybridization; D008264:Macrophages / Q000378:metabolism / Q000473:pathology; D008297:Male; D009203:Myocardial Infarction / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D015676:Osteonectin / Q000235:genetics / Q000378:metabolism*; D053495:Osteopontin; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012795:Sialoglycoproteins / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors
chemical_list: D024042:Collagen Type I; D015676:Osteonectin; D012333:RNA, Messenger; D012795:Sialoglycoproteins; C506897:Spp1 protein, rat; D053495:Osteopontin