Regulation of hyaluronan-stimulated VCAM-1 expression in murine renal tubular epithelial cells.
BACKGROUND
Cytokines stimulate the expression of the adhesion molecule VCAM-1 in renal tubular epithelial cells. We have recently shown that VCAM-1 can also be upregulated by low molecular weight breakdown products of the matrix constituent hyaluronan (HA) (J Immunol 1998; 161: 3431-3437). The mechanisms of VCAM-I expression in response to HA remain to be defined.


METHODS
Using a defined mouse cortical tubular (MCT) cell line we investigated the effect of protein kinase C (PKC) and tyrosine kinase (TK) inhibition on the HA-stimulated VCAM-1 expression by cell ELISA and RT PCR or Northern blotting. Furthermore, we examined the effect of PKC and TK inhibition on NF-kappaB.


RESULTS
We found that the PKC inhibitor GF109203X (acting on conventional, novel and atypical isoforms) inhibited the HA-stimulated VCAM-1 expression in MCT cells dose-dependently up to 90%, whereas chelerythrine (acting on conventional and novel isoforms) had no effect. Downregulation of PKC with PMA did not prevent the HA-stimulated VCAM-1 expression, suggesting that Ca2+- and diacylglycerol-independent (atypical) isoforms of PKC are involved. The TK inhibitor genistein also inhibited the HA-stimulated VCAM-1 expression at the mRNA and protein level up to 70%. Interestingly, the HA-stimulated nuclear translocation of NF-kappaB could not be prevented with GF109203X and genistein.


CONCLUSIONS
These data demonstrate that the HA-stimulated VCAM-1 expression in MCT cells involves PKC and TK pathways. The absence of an effect of PKC and TK inhibitors on the nuclear translocation of NF-kappaB suggests that additional transcription factors are involved for VCAM-1 expression.
Schawalder
A
A
Physiological Institute, University of Zürich-Irchel, Switzerland.
Oertli
B
B
Beck-Schimmer
B
B
Wüthrich
R P
RP
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D006820:Hyaluronic Acid / Q000494:pharmacology*; D007527:Isoenzymes / Q000378:metabolism; D007672:Kidney Cortex; D007684:Kidney Tubules / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D051379:Mice; D016328:NF-kappa B / Q000502:physiology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D012333:RNA, Messenger / Q000037:antagonists & inhibitors; D019010:Vascular Cell Adhesion Molecule-1 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
D004791:Enzyme Inhibitors; D007527:Isoenzymes; D016328:NF-kappa B; D012333:RNA, Messenger; D019010:Vascular Cell Adhesion Molecule-1; D006820:Hyaluronic Acid; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C