Transforming growth factor beta isoforms in human glomerulonephropathies

Transforming growth factor beta (TGF beta) is a multifunctional cytokine fo r which three isoforms, TGF beta 1, -2 and -3 have been characterized in ma mmals. Several reports suggest an involvement of TGF beta in the cellular a nd molecular basis of renal fibrosis. Most of these studies have focused ex clusively on TGF beta 1. Here we demonstrate using reverse transcriptase po lymerase chain reaction (RT-PCR) that transcripts from all three isoforms o f TGF beta were detected in 31 renal biopsies, control tissue and cultured human mesangial cells. A novel alternative transcript of TGF beta 2 was ide ntified in renal tissue. The variation in transcript levels detected using this technique did not exhibit a striking correlation with any specific dis ease type. In addition, complement deposition and localization (i.e. mesang ial or capillary wall) does not appear to have any direct correlation with the occurrence of a particular TGF beta isoform transcript. It is likely th at dynamic changes in all TGF beta transcript levels occur in normal and di seased kidneys as a response to physiological and pathological demands. Mos t investigations have focused on one TGF beta isoform neglecting the contri bution of the others. Studies which analyse all known isoforms and their al ternative transcripts may establish the interplay between these during the progression of renal disease.