The American journal of pathology
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Neuronal protein 3.1 (P311), a conserved RNA-binding protein, represents the first documented protein known to stimulate transforming growth factor (TGF)-β1 to -β3 translation in vitro and in vivo. Because TGF-βs play critical roles in fibrogenesis, we initiated efforts to define the role of P311 in skin scar formation. Here, we show that P311 is up-regulated in skin wounds and in normal and hypertrophic scars. ⋯ Finally, exogenous TGF-β1 to -β3, each restituted the normal scar phenotype. These studies demonstrate that P311 is required for the production of normal cutaneous scars and place P311 immediately up-stream of TGF-βs in the process of fibrogenesis. Conditions that decrease P311 levels could result in less tensile scars, which could potentially lead to higher incidence of dehiscence after surgery.
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Mucus hypersecretion is an important pathologic feature of chronic obstructive pulmonary disease. Activating transcription factor 3 (ATF3) is an adaptive-response gene that participates in various cellular processes. However, little is known about its role in cigarette smoke (CS)-induced mucus hyperproduction. ⋯ In vivo, the Atf3-/- mice also displayed a significantly reduced mucus production relative to wild-type controls in response to chronic CS exposure. Furthermore, a chromatin immunoprecipitation assay revealed increased ATF3 binding to the MUC5AC promoter after CS treatment, and this transcriptional binding was significantly inhibited by knockdown of JUN, a subunit of activator protein-1. These results demonstrate that ATF3 may be involved in activator protein-1 signaling and transcriptional promotion of CS-induced MUC5AC expression in airway epithelial cells.