Iyoda et al. have provided strong experimental evidence for beneficial effects of PDGF signalling inhibition in two seemingly unrelated glomerular diseases: rapidly progressive glomerulonephritis (RPGN) in the present study and focal and segmental glomerulosclerosis (FSGS) in a previous study. Novel insights into the pathogenesis of these two diseases have unravelled a common cellular mechanism: activation of parietal epithelial cells (PECs). In addition, recent studies have shown that PDGF signalling is sufficient to mediate the PEC activation and formation of cellular crescents, the hallmark of RPGN. In this comment, we make an attempt to assemble the pieces of the puzzle arguing that the activated PECs might play a significant role and could represent a target for novel treatment strategies for RPGN and FSGS.