Regulation and profibrogenic effects of TGF-β1 signaling in mast cells, a cell type contributing to the outcome of hepatic injury

Background: In the setting of mastocytosis, mast cells have been shown to promote renal and lung fibrosis, whereas their effect in the liver is under debate [1 – 4]. Mast cell effects are based on the secretion of mitogenic and profibrotic, e.g. TGF-β1, cytokines – leading to activation and proliferation of fibroblasts [5] – and proteases – causing a direct or indirect modulation of extracellular matrix homeostasis [6]. Besides these paracrine effects, mast cells are able to process TGF-β1 signals on their own but the exact mechanisms and responses are less well characterized.