[HTML][HTML] The early growth response gene Egr2 (Alias Krox20) is a novel transcriptional target of transforming growth factor-β that is up-regulated in systemic sclerosis …

F Fang, K Ooka, S Bhattachyya, J Wei, M Wu… - The American journal of …, 2011 - Elsevier
F Fang, K Ooka, S Bhattachyya, J Wei, M Wu, P Du, S Lin, F Del Galdo, CA Feghali-Bostwick…
The American journal of pathology, 2011Elsevier
Although the early growth response-2 (Egr-2, alias Krox20) protein shows structural and
functional similarities to Egr-1, these two related early-immediate transcription factors are
nonredundant. Egr-2 plays essential roles in peripheral nerve myelination, adipogenesis,
and immune tolerance; however, its regulation and role in tissue repair and fibrosis remain
poorly understood. We show herein that transforming growth factor (TGF)-β induced a
Smad3-dependent sustained stimulation of Egr2 gene expression in normal fibroblasts …
Although the early growth response-2 (Egr-2, alias Krox20) protein shows structural and functional similarities to Egr-1, these two related early-immediate transcription factors are nonredundant. Egr-2 plays essential roles in peripheral nerve myelination, adipogenesis, and immune tolerance; however, its regulation and role in tissue repair and fibrosis remain poorly understood. We show herein that transforming growth factor (TGF)-β induced a Smad3-dependent sustained stimulation of Egr2 gene expression in normal fibroblasts. Overexpression of Egr-2 was sufficient to stimulate collagen gene expression and myofibroblast differentiation, whereas these profibrotic TGF-β responses were attenuated in Egr-2–depleted fibroblasts. Genomewide transcriptional profiling revealed that multiple genes associated with tissue remodeling and wound healing were up-regulated by Egr-2, but the Egr-2–regulated gene expression profile overlapped only partially with the Egr-1–regulated gene profile. Levels of Egr-2 were elevated in lesional tissue from mice with bleomycin-induced scleroderma. Moreover, elevated Egr-2 was noted in biopsy specimens of skin and lung from patients with systemic sclerosis. These results provide the first evidence that Egr-2 is a functionally distinct transcription factor that is both necessary and sufficient for TGF-β–induced profibrotic responses and is aberrantly expressed in lesional tissue in systemic sclerosis and in a murine model of scleroderma. Together, these findings suggest that Egr-2 plays an important nonredundant role in the pathogenesis of fibrosis. Targeting Egr-2 might represent a novel therapeutic strategy to control fibrosis.
Elsevier