Mesangial cell expression of proto-oncogene Ets-1 during progression of mesangioproliferative glomerulonephritis.
BACKGROUND
Ets-1 is a transactivator of matrix-associated genes and key factor in neoangiogenesis. The expression of Ets-1 mRNA and protein was analyzed in healthy rat kidney and in a model for mesangioproliferative disease without and with inhibition of platelet-derived growth factor-B (PDGF-B) activity.


METHODS
Immunohistochemistry was performed using a specific noncrossreacting anti-Ets-1 antibody and included a counterstain with alpha-smooth muscle actin (alpha-SMA). Nuclear proteins from isolated glomeruli were analyzed by Western blotting. Changes in Ets-1 mRNA levels were detected by in situ hybridization and Northern blotting. PDGF-B antagonism was performed in nephritic rats by specific aptamers.


RESULTS
The distribution of Ets-1-positive cells in healthy rats was heterogenous with exclusively nuclear staining of glomerular, tubular, and vascular cells. Profound changes were detected in the anti-Thy 1.1 glomerulonephritis. Nuclear Ets-1 staining was intense in mesangial cells, whereas podocyte and endothelial cell staining was unchanged. The strongest signal was seen on days 2 to 7. By Western blotting of glomerular proteins a single 52 kD band was detected in healthy rats, which was increased 4.5-fold after disease induction. At the same time a 54 kD band appeared that most likely represents phosphorylated Ets-1. Ets-1 transcripts were detected in mesangial cells that include exon IV but lack exon VII. A concordant 6.4-fold up-regulation of mRNA was detected in glomeruli. Specific PDGF-B antagonism by aptamer treatment from days 3 to 7 after disease induction led to reduced Ets-1 expression on day 7, correlating with decreased mesangial cell numbers.


CONCLUSIONS
A temporal increase of mesangial cell Ets-1 expression correlates with mesangial cell activation in mesangioproliferative glomerulonephritis. PDGF-B may partially contribute to the increased expression.
Raffetseder
Ute
U
Department of Nephrology & Clinical Immunology, University Hospital of Aachen, Aachen, Germany.
Wernert
Nico
N
Ostendorf
Tammo
T
van Roeyen
Claudia
C
Rauen
Thomas
T
Behrens
Peter
P
Floege
Jurgen
J
Mertens
Peter R
PR
D017398:Alternative Splicing; D000818:Animals; D015152:Blotting, Northern; D002478:Cells, Cultured; D004195:Disease Models, Animal; D018450:Disease Progression; D015870:Gene Expression / Q000502:physiology; D005920:Glomerular Mesangium / Q000166:cytology / Q000502:physiology*; D015432:Glomerulonephritis, Membranoproliferative / Q000378:metabolism / Q000503:physiopathology*; D017403:In Situ Hybridization; D007518:Isoantibodies; D008297:Male; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D050783:Proto-Oncogene Proteins c-ets; D020574:Proto-Oncogene Proteins c-sis / Q000037:antagonists & inhibitors; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
C494043:Ets1 protein, rat; D007518:Isoantibodies; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger; D014157:Transcription Factors; C035678:anti-Thy antibody