Platelet derived growth factor and interleukin-1 expression are increased in murine IgA nephropathy

Abstract

Proliferation of glomerular cells and increase of extracellular matrix are major histological features of many glomerular diseases in humans as well as experimental animals. Rat mesangial cells in culture express Platelet Derived Growth factor (PDGF) and Interleukin (IL)-1 messenger (m) RNAs and proliferate in response to PDGF and to IL-1 (1, 2, 3). PDGF, stored in platelet α-granules, is a potent mitogen for cells of mesenchymal origin, and one of the principal mitogens in serum. It exists in three forms: either homodimer or the heterodimer of two distinct polypeptide chains (A and B), encoded by two separate genes. Besides its potent mitogenic effect, PDGF has several biological activities including chemoattraction, activation of inflammatory cells, stimulation of extracellular matrix synthesis by mesenchymal cells and potent contraction of aortic smooth muscle cells (4). IL-1 exists in two different forms: α and β. Synthesized by both leukocytic as well as nonleukocytic cells, IL-1 shares several biological activities with PDGF (5).