Influence of hepatocyte growth factor, epidermal growth factor, and mycophenolic acid on endothelin-1 synthesis in human endothelial cells.
BACKGROUND
Endothelin-1 (ET-1) is a potent vasoconstrictive peptide which plays an important pathophysiological role in ischaemic renal failure and drug-induced renal injury such as cyclosporin A (CsA)- and tacrolimus-associated nephrotoxicity. In contrast, hepatocyte growth factor (HGF) and epidermal growth factor (EGF) seem to accelerate renal regeneration after ischaemic and drug-induced renal injury. This study aimed to investigate the influence of HGF and EGF on ET-1 synthesis in cultured human umbilical vein endothelial cells (HUVEC) and renal artery endothelial cells (RAEC). In addition, we have investigated whether mycophenolic acid (MPA), a new immunosuppressive drug, which in contrast to CsA and tacrolimus lacks nephrotoxic side effects, modulates ET-1 synthesis in endothelial cells.


METHODS
ET-1 release was measured with a specific enzyme-linked immunosorbent assay. ET-1 mRNA expression was investigated by reverse transcription polymerase chain reaction.


RESULTS
HGF and EGF (0.001-10 nM) exerted a significant concentration-dependent inhibitory effect on ET-1 release by HUVEC and RAEC (minimum 56.1+/-4.3% of control, n=6, mean+/-SE). The suppressive effect of HGF and EGF on ET-1 synthesis was dose-dependently antagonized by the tyrosine kinase inhibitors tyrphostin AG1478, lavendustin A and methyl 2,5-dihydroxycinnamate. Incubation of HUVEC and RAEC with MPA (2.5, 10, 25, and 50 microg/ml) for 3-5 h induced a significant reduction of ET-1 mRNA expression. After 48 h incubation with MPA (1-50 microg/ml) a significant decrease of ET-1 release and DNA content per culture well was observed, whereas ET-1 release referred to the DNA content in the corresponding culture well did not differ significantly from controls.


CONCLUSIONS
The present findings demonstrate that HGF and EGF reduce ET-1 synthesis in endothelial cells via their receptor tyrosine kinase activity and suggest that the renoprotective effects of HGF and EGF might be linked to their inhibitory action on ET-1 synthesis. This study also provides evidence that, in contrast to CsA and tacrolimus, MPA does not stimulate ET-1 synthesis. This might explain the clinical observation that renal function often improves when CsA or tacrolimus is replaced by mycophenolate mofetil.
Haug
C
C
Institute of Clinical Chemistry, University Hospital, Ulm, Germany. cornelia.haug@medizin.uni-ulm.de
Schmid-Kotsas
A
A
Linder
T
T
Bachem
M G
MG
Gruenert
A
A
Rozdzinski
E
E
D002478:Cells, Cultured; D019332:Endothelin-1 / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D017228:Hepatocyte Growth Factor / Q000494:pharmacology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D009173:Mycophenolic Acid / Q000494:pharmacology*; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000378:metabolism; D012077:Renal Artery; D014471:Umbilical Veins
D019332:Endothelin-1; D007166:Immunosuppressive Agents; D012333:RNA, Messenger; D004815:Epidermal Growth Factor; D017228:Hepatocyte Growth Factor; D009173:Mycophenolic Acid