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Giuseppina De Petro, Daniela Tavian, Eleonora Marchina, Sergio Barlati
Induction of Fibronectin mRNA by Urokinase- and Tissue-Type Plasminogen Activator in Human Skin Fibroblasts: Differential Role of u-PA and t-PA at the Fibronectin Protein Level
Plasminogen activators of the urokinase and tissuetype and fetal calf serum (uPA, tPA, FCS) exert their mitogenic effect on quiescent human dermal fibroblasts and modulate the mRNA expression of cellcycle related genes. The present study deals with the effects of PAs on the expression of fibronectin (FN), a heterodimeric extracellular matrix (ECM) protein that can be modulated in different ways by various mitogens. The kinetics of FN gene response was examined in quiescent fibroblasts upon PA stimulation (30 min 24 h). The results obtained evidenced that: (i) all mitogens tested (uPA, tPA and FCS) led to an increase of FN mRNA expression in early G1, as shown by the analysis of two sequences, III-9, common to all FN mRNAs, and EDA+, present only in the EDA+FN isoform; (ii) the kinetic profiles of FN mRNA stimulation were comparable for the three mitogens, although the effects on the FNECM assembly were distinct; (iii) tPA and FCS led to FN assembly in the ECM, which was absent or decreased in uPAtreated cultures. Immunobiochemical analysis of total FN and EDA + FN showed that FN induced by tPA was mainly dimeric (450 500 kDa), whereas FN induced by uPA was mainly monomeric (230 250 kDa). These differences are probably due to the differential enzymatic action of tPA and uPA on FN, which might be related to a differential role of the two PAs in several physiopathological conditions.
Biological Chemistry, Walter de Gruyter
Print ISSN: 1431-6730
Volume: 383, 01/2002
Pages: 177 - 187