Figure 5.

Overview of HIF signaling in CKD. Shown is a summary of potential mechanisms by which epithelial HIF-1 could act as a profibrotic transcription factor. These include the regulation of ECM production and processing through matrix modifying factors and enzymes, such as CTGF, PAI-1, TIMP-1 and MMPs, and the modulation of EMT triggering pathways. The role of non-epithelial HIF in the pathogenesis of renal fibrogenesis is not known. Abb.: CTGF, connective tissue growth factor; ECM, extra-cellular matrix; EMT, epithelial to mesenchymal transition; NO, nitric oxide; PAI-1, plasminogen activator inhibitor 1; ROS, reactive oxygen species; TIMP-1, tissue-inhibitor of metalloproteinase 1.