title: Transforming growth factor-beta controls cell-matrix interaction of microvascular dermal endothelial cells by downregulation of integrin expression.
abstract: Transforming growth factor-beta (TGF-beta) is a pleiotropic regulatory factor of tissue remodeling. Angiogenesis, a prerequisite of tissue repair and tissue expansion, is induced by TGF-beta in vivo, while proliferation and migration of cultured endothelial cells are inhibited by TGF-beta. Indirect mechanisms stimulating angiogenesis and modification of TGF-beta effects by cell-matrix interaction have been postulated to account for this paradigm. Because cellular behavior in tissue remodeling is decisively determined by cell-matrix interactions, which in turn is mediated via integrins, we investigated the effect of TGF-beta on matrix-dependent endothelial cell functions. Integrin expression of human dermal microvascular endothelial cells (HDMEC) was measured by Northern blot and fluorescence-activated cell sorter analysis after TGF-beta treatment and correlated to cell-matrix interactions, which were studied in a colorimetric cell attachment assay as well as the Boyden chamber chemotaxis assay. We found a cell-specific downregulation of integrin expression in HDMEC on the level of mRNA as well as on the cell surface. This effect correlated well with the reduction of integrin-dependent cell adhesion to several matrix proteins, in particular to fibronectin. Moreover, TGF-beta decreased fibronectin-induced chemotaxis of HDMEC. Thus, TGF-beta controls cell-matrix interaction of HDMEC by down-regulation of integrin expression. This effect of TGF-beta reflects direct and cell-specific control mechanisms on microvascular cells that may be critical for the coordinated process of angiogenesis requiring a balance of stimulatory and inhibitory factors.
authors.affiliation: Department of Dermatology, Ludwig Maximilians Universität, Munich, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Frank
authors.forename: B C
authors.initials: BC
authors.lastname: Adelmann-Grill
authors.forename: K
authors.initials: K
authors.lastname: Herrmann
authors.forename: U F
authors.initials: UF
authors.lastname: Haustein
authors.forename: J B
authors.initials: JB
authors.lastname: Petri
authors.forename: M
authors.initials: M
authors.lastname: Heckmann
mesh_terms: D002448:Cell Adhesion; D002478:Cells, Cultured; D002633:Chemotaxis / Q000187:drug effects; D015536:Down-Regulation; D004730:Endothelium, Vascular / Q000166:cytology*; D005109:Extracellular Matrix / Q000502:physiology*; D016326:Extracellular Matrix Proteins / Q000502:physiology; D006801:Humans; D016023:Integrins / Q000502:physiology*; D008833:Microcirculation; D012867:Skin / Q000098:blood supply*; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
chemical_list: D016326:Extracellular Matrix Proteins; D016023:Integrins; D016212:Transforming Growth Factor beta