Different effects of growth factors on human renal early distal tubular cells in vitro.
BACKGROUND
In the kidney, recovery from tubular damage requires regenerative mechanisms leading to re-epithelialization of the injured tubules. Current evidence supports the para- or autocrine role of growth factors in repair and regeneration of ischemic or nephrotoxic experimental acute renal failure.


METHODS
We evaluated the effects of EGF, HGF, IGF-1, and bFGF on human renal thick ascending limb and distal convoluted cells (TALDC) in vitro. TALDC were isolated by immunomagnetic separation and cultured. Signal transduction of the growth factors was evaluated by Western blot of ERK1/2 MAP-K phosphorylation. Cell proliferation was measured by MTT assay and a fluorometric assay.


RESULTS
A significant, dose- and time-dependent phosphorylation of ERK1/2 could be detected exclusively after stimulation with EGF. No other growth factor induced a significant MAPK phosphorylation. In the same manner, proliferation assays showed a significant growth-promoting effect of EGF. Neither HGF, nor IGF-1 or bFGF showed a stimulative effect on TALDC proliferation.


CONCLUSIONS
The present study highlights the effects of growth factors on cultured TALDC and supports the hypothesis that in vivo EGF plays a para- or autocrine role during renal repair mechanisms.
Baer
Patrick C
PC
Department of Internal Medicine III, Division of Nephrology, J.W. Goethe University, Frankfurt am Main, Germany. P.Baer@em.uni-frankfurt.de
Geiger
Helmut
H
D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004815:Epidermal Growth Factor / Q000494:pharmacology; D066246:ErbB Receptors / Q000235:genetics; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D017228:Hepatocyte Growth Factor / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology*; D007686:Kidney Tubules, Distal / Q000166:cytology*; D008138:Loop of Henle / Q000166:cytology; D010766:Phosphorylation / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*
D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D016222:Fibroblast Growth Factor 2; D004815:Epidermal Growth Factor; D017228:Hepatocyte Growth Factor; D007334:Insulin-Like Growth Factor I; D066246:ErbB Receptors; D048049:Extracellular Signal-Regulated MAP Kinases