Updates and Knowledge Gaps in Cholesteatoma Research

Figure 4

Schematic representation of the paracrine and autocrine interactions between matrix keratinocytes and perimatrix fibroblasts. Keratinocytes release proinflammatory cytokines (e.g., IL-1α, IL-1β, IL-6, PTHrP, and IL-8), which subsequently induce fibroblasts to secrete several cytokines (e.g., KGF, GM-CSF, EGF, TNF-α, PDGF, and TGF-α). These fibroblast-derived cytokines in turn induce the differentiation, proliferation, and migration of matrix keratinocytes. In addition, the TGF-α and TGF-β are upregulated in an autocrine loop, regulating keratinocyte proliferation and differentiation. EGF: epidermal growth factor; GM-CSF: granulocyte-macrophage colony stimulating factor; IL: interleukin; KGF: keratinocytes growth factor; PDGF: platelet-derived growth factor; PTHrP: parathyroid-hormone-related protein; TGF: transforming growth factor; TNF-α: tumor necrosis factor alpha.