Collagen I upregulates extracellular matrix gene expression and secretion of TGF-beta 1 by cultured human mesangial cells.
Progressive renal diseases are characterized by an increased synthesis of extracellular matrix (ECM) components. The mechanisms involved in the development of these alterations are not completely known, but a crucial role for TGF-beta 1 has been suggested. Moreover, the ability of the ECM to modulate the phenotypic expression of different cell types has been widely described. In experiments presented here, human mesangial cells (HMC) were grown on collagen type I (COL I) or IV (COL IV). ECM protein and TGF-beta 1 mRNA expression were evaluated by Northern blot analysis, and TGF-beta 1 secretion was evaluated by ELISA. The involvement of tyrosine kinase and serine-threonine kinase pathways was studied by Western blot analysis, immunofluorescence, and in vitro kinase assays. HMC cultured on COL I showed an increased mRNA expression of COL I and COL IV, fibronectin, and TGF-beta 1. Both tyrosine phosphorylation and integrin-linked kinase (ILK) activity increased when HMC were cultured on COL I, and blockade of these pathways inhibited the increased secretion of TGF-beta 1. In conclusion, the present results support a role for extracellular COL I in the regulation of TGF-beta 1 synthesis during progressive renal sclerosis and fibrosis and the subsequent increase in newly synthesized ECM proteins. In addition, ILK, along with the tyrosine kinases, participates in the genesis of this effect.
Ortega-Velazquez
R
R
Department of Physiology, Alcala University, Alcalá de Henares, Madrid, Spain. mpiedad.ruiz@uah.es
Gonzalez-Rubio
M
M
Ruiz-Torres
M P
MP
Diez-Marques
M L
ML
Iglesias
M C
MC
Rodríguez-Puyol
M
M
Rodríguez-Puyol
D
D
D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism* / Q000494:pharmacology; D024141:Collagen Type IV / Q000378:metabolism / Q000494:pharmacology; D005109:Extracellular Matrix / Q000235:genetics*; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis / Q000235:genetics; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D005920:Glomerular Mesangium / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D053773:Transforming Growth Factor beta1; D014443:Tyrosine / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics; D000099200:Scaffold Protein ILK
D024042:Collagen Type I; D024141:Collagen Type IV; D016326:Extracellular Matrix Proteins; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D014443:Tyrosine; D000099200:Scaffold Protein ILK; C508960:TGFB1 protein, human