Osteogenic responses in fibroblasts activated by elastin degradation products and transforming growth factor-beta1: role of myofibroblasts in vascular calcification.
Our objective was to establish the role of fibroblasts in medial vascular calcification, a pathological process known to be associated with elastin degradation and remodeling. Rat dermal fibroblasts were treated in vitro with elastin degradation products and transforming growth factor (TGF)-beta1, factors usually present in deteriorated matrix environments. Cellular changes were monitored at the gene and protein level by reverse transcriptase-polymerase chain reaction, enzyme-linked immunosorbent assay, immunofluorescence, and von Kossa staining for calcium deposits. By 21 days, multicellular calcified nodules were formed in the presence of elastin degradation products and TGF-beta1 separately and to a significantly greater extent when used together. Before mineralization, cells expressed alpha-smooth muscle actin and large amounts of collagen type I and matrix metalloproteinase-2, characteristic features of myofibroblasts, key elements in tissue remodeling and repair. Stimulated cells expressed increased levels of core-binding factor alpha1, osteocalcin, alkaline phosphatase, and osteoprotegerin, representative bone-regulating proteins. For most proteins analyzed, TGF-beta1 synergistically amplified responses of fibroblasts to elastin degradation products. In conclusion, elastin degradation products and TGF-beta1 promote myofibroblastic and osteogenic differentiation in fibroblasts. These results support the idea that elastin-related calcification involves dynamic remodeling events and suggest the possibility of a defective tissue repair process.
Simionescu
Agneta
A
Department of Bioengineering, 501 Rhodes Center, Clemson University, Clemson, SC 29634, USA.
Simionescu
Dan T
DT
Vyavahare
Narendra R
NR
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002454:Cell Differentiation; D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism; D050659:Core Binding Factor Alpha 1 Subunit / Q000502:physiology*; D004549:Elastin / Q000378:metabolism*; D005347:Fibroblasts / Q000502:physiology*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D009130:Muscle, Smooth / Q000166:cytology* / Q000378:metabolism; D010012:Osteogenesis; D053244:Osteoprotegerin / Q000378:metabolism; D051381:Rats; D012867:Skin / Q000166:cytology; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*; D015854:Up-Regulation
D024042:Collagen Type I; D050659:Core Binding Factor Alpha 1 Subunit; D053244:Osteoprotegerin; D053773:Transforming Growth Factor beta1; D004549:Elastin; D020778:Matrix Metalloproteinase 2; D002118:Calcium