Induction of heat shock protein 47 synthesis by TGF-β and IL-1β via enhancement of the heat shock element binding activity of heat shock transcription factor 1

H Sasaki, T Sato, N Yamauchi, T Okamoto… - The Journal of …, 2002 - journals.aai.org
H Sasaki, T Sato, N Yamauchi, T Okamoto, D Kobayashi, S Iyama, J Kato, T Matsunaga…
The Journal of Immunology, 2002journals.aai.org
With most immunological reactions, tissue fibrosis, collagen overproduction caused by
immune cytokines, is inevitably associated. Among the various immune cytokines, heat
shock protein 47 (HSP47) is a procollagen-specific molecular chaperon and is essential for
secretion of procollagen from cells. Induction of HSP47 by TGF-β has been previously
reported in rat skeletal myoblasts and mouse osteoblasts, but not in human diploid
fibroblasts. As for IL-1β, its effect on HSP47 has not been elucidated. In the present study …
Abstract
With most immunological reactions, tissue fibrosis, collagen overproduction caused by immune cytokines, is inevitably associated. Among the various immune cytokines, heat shock protein 47 (HSP47) is a procollagen-specific molecular chaperon and is essential for secretion of procollagen from cells. Induction of HSP47 by TGF-β has been previously reported in rat skeletal myoblasts and mouse osteoblasts, but not in human diploid fibroblasts. As for IL-1β, its effect on HSP47 has not been elucidated. In the present study, using human embryonic lung fibroblast cells, we first disclosed that both TGF-β and IL-1β induced HSP47 synthesis. We then revealed that the binding of the heat shock element (HSE) by heat shock transcription factor 1 (HSF1) was enhanced by both cytokines. We further demonstrated that trimer formation of HSF1, which is essential for its binding to HSE, was induced by these cytokines. The enhancement of HSP47 synthesis and their trimer formation of HSF1 were augmented by using a combination of both cytokines. Collectively, TGF-β and IL-1β were found to induce trimer formation of HSF1 which in turn bound to HSE of HSP47, resulting in the enhancement of HSP47 expression. Thus, HSP47 could well be a good candidate for molecular targeting in controlling tissue fibrosis, given that both principal fibrinogenetic cytokines (TGF-β, IL-1β) are commonly involved in its induction through HSF1 trimerization.
journals.aai.org