Pancreatic stellate cell: Pandora's box for pancreatic disease biology

Figure 4 Signaling pathways mediating pancreatic stellate cell activation. Expression of α-SMA, proliferation, migration and deposition of matrix proteins are the important properties attained by activated pancreatic stellate cells (PSCs) when stimulated with various growth factors and proinflammatory cytokines. Proliferation and migration is mediated through the MAP kinase and PI3K pathways when PSCs are stimulated with HNE, alcohol, PDGF and IL-33 and other cytokines. TGF-β1 induces the Smad proteins and stimulates the proliferation and collagen secretion by PSCs. Activation of Indian Hedgehog (IHH) signaling in PSCs promotes their migration, proliferation and collagen deposition. PSC mediated Sonic Hedgehog (SHH) signaling promotes cancer cell invasion and migration. Wnt signaling can cause collagen deposition and cancer progression. PDGF: Platelet derived growth factor; HNE: Hydroxy-nonenal; ERK: Extracellular signal-regulated kinases; JNK: c-Jun N-terminal kinase; TGF-β: Transforming growth factor-β; α-SMA: α-smooth muscle actin; COX-2: Cyclooxygenase-2; IL: Interleukin.