Expression of two alternative transcription forms of platelet-derived growth factor-A chain in the normal human kidney and in glomerulonephritis.
OBJECTIVE
Up to now, a role of platelet-derived growth factor (PDGF)-AA in glomerulonephritis (GN) remains unclear. PDGF-A chain may be produced in two forms, as a result of the alternative splicing.


METHODS
We examined the expression of this growth factor in the renal tissue of 57 patients with GN and seven normal kidneys (NK). The gene expression of PDGF-A was examined by reverse transcriptase-polymerase chain reaction. Sets of primers allowing distinction between the two forms of transcripts were used. Specificity of the PCR products was confirmed by restriction enzyme analysis and sequencing. The expression of PDGF-AA/AB was also evaluated by immunohistochemistry.


RESULTS
Compared to NK, the expression of PDGF-A gene was higher in the renal tissue with GN. This expression was higher in non-proliferative GN (NPGN) than in proliferative forms of GN (PGN) (1.24 +/- 0.34 vs. 0.86 +/- 0.14). In NK, both forms of transcripts (N = 4) or only the short one (N = 3) were found. In 45.5% of patients with NPGN, only the short form could be detected. In contrast, in 68.6% of patients with PGN both or only the longer form of transcripts were found. In NK, a faint staining for PDGF-AA/AB was observed within glomerular capillaries, whereas a statistically significant increase in this protein expression was particularly stated in NPGN. These results suggest that the production of the longer PDGF-A chain variant is associated with glomerular cells' proliferation. However, the higher expression of PDGF-AA/AB protein in NPGN could indicate an essential role of this growth factor in the maintaining the glomerular architecture.
Miller-Kasprzak
E
E
Laboratory for Molecular Nephrology, Department of Nephrology, Transplantology and Internal Diseases, University of Medical Sciences, Poznań, Poland.
Olejniczak
P
P
Kubiak
A
A
Polcyn-Adamczak
M
M
Niemir
Z I
ZI
D000293:Adolescent; D000328:Adult; D017398:Alternative Splicing; D016022:Case-Control Studies; D002648:Child; D005260:Female; D005921:Glomerulonephritis / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010982:Platelet-Derived Growth Factor / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic; D015854:Up-Regulation
D010982:Platelet-Derived Growth Factor; C075278:platelet-derived growth factor A; C095477:platelet-derived growth factor AB