BACKGROUND:
Heat shock protein (HSP) 47, a collagen-specific molecular chaperone, is involved in the processing and/or secretion of procollagen. HSP47 is consistently and dramatically upregulated in a variety of fibrotic diseases. The aim of this study was to compare HSP47 expression in normal human buccal mucosa and oral submucous fibrosis (OSF) specimens and further to explore the potential mechanisms that may lead to induce HSP47 expression.
METHODS:
The mRNA levels of HSP47 from fibroblasts cultured from 20 OSF and 10 normal buccal mucosal fibroblasts (BMFs) were evaluated by reverse transcription polymerase chain reaction. The effect of arecoline, the major areca nut alkaloid, was added to explore the potential mechanisms that may lead to induce HSP47 expression. Furthermore, mitogen-activated protein kinase kinase (MEK) inhibitor U0126, phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002, p38 inhibitor SB203580, cyclo-oxygenase-2 (COX-2) inhibitor NS-398, and glutathione precursor N-acetyl-l-cysteine were added to find the possible mechanisms.
RESULTS:
OSF demonstrated significantly higher HSP47 mRNA expression than BMFs (P < 0.001). Arecoline was also found to elevate HSP47 mRNA expression in a dose-dependent manner (P < 0.05). The amount of HSP47 was about 3.7-fold at a concentration level of 80 microg/ml arecoline when compared with control (P < 0.05). In addition, pre-treatment with pharmacologic agents markedly inhibited the arecoline-induced HSP47 mRNA expression (P < 0.05).
CONCLUSIONS:
Taken together, HSP47 is significantly upregulated in OSF from areca quid chewers and HSP47 expression induced by arecoline in fibroblasts may be mediated by MEK, PI3K, and COX-2 signal transduction pathways.
