Polymerase chain reaction and focal contact formation indicate integrin expression in mesangial cells.
Cultured kidney glomerular mesangial cells (MCs) allow the role of extracellular matrix (ECM) and growth factors in glomerular inflammatory disease to be studied. To investigate the potential of MCs to interact with matrix components, the expression of integrin mRNA in cultured MCs was examined by polymerase chain reaction (PCR), by Northern blotting and by immunofluorescence. In addition, the effect of matrix substrates on mRNA expression was assessed by PCR. Northern blots with cDNA probes to integrin alpha-chains revealed that MCs expressed alpha 1, alpha 3 and alpha 5 integrin mRNA. alpha 1 and alpha 3 were the major messages. No alpha 2, alpha 4 or alpha 6 were detectable. RT-PCR revealed that alpha 2 and alpha 6 were also expressed at low levels. The control cells, HT1080, expressed alpha 2, alpha 3, alpha 4, alpha 5 and alpha 6 mRNA, and Rugli expressed alpha 1, alpha 3 and alpha 5, supporting previous studies. Immunocytochemistry confirmed that alpha 1 beta 1, alpha 2 beta 1, and alpha 5 beta 1 integrins were expressed and that they were concentrated into focal adhesions (alpha 1 beta 1 on type I collagen and laminin; alpha 2 beta 1 on type I collagen; alpha 3 beta 1 on type I collagen, laminin and fibronectin; alpha 5 beta 1 on fibronectin). alpha 6 beta 1 was not detected in focal contacts. Attachment, spreading, and formation of talin and integrin containing focal contacts still occurred when endogenous protein synthesis was blocked with 30 micrograms.ml-1 cycloheximide.(ABSTRACT TRUNCATED AT 250 WORDS)
Petermann
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Nephrology Research Laboratory, Medizinische Klinik IV, University of Erlangen-Nürnberg, Germany.
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Grenz
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Goodman
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Sterzel
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D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D005920:Glomerular Mesangium / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D016023:Integrins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D015335:Molecular Probes / Q000235:genetics; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D014158:Transcription, Genetic
D016023:Integrins; D015335:Molecular Probes; D012333:RNA, Messenger