The upregulation of heat shock protein 47 in human gingival fibroblasts stimulated with cyclosporine A.
OBJECTIVE
Heat shock protein 47 (Hsp47), a collagen-specific molecular chaperone, is involved in the processing and/or secretion of procollagen. Heat shock protein 47 is consistently and dramatically upregulated in a variety of fibrotic diseases. The aim of this study was to compare Hsp47 expression in normal gingival tissues and cyclosporine A-induced gingival overgrowth specimens and further explore the potential mechanisms that may lead to induction of Hsp47 expression.


METHODS
Fifteen cyclosporine A-induced gingival overgrowth specimens and five normal gingival tissues were examined by immunohistochemistry. Western blot was used to investigate the effects of cyclosporine A on the expression of Hsp47 in human gingival fibroblasts. In addition, Aggregatibacter actinomycetemcomitans, interleukin-1 alpha (IL-1 alpha) and mitogen-activated protein kinase kinase (MEK) inhibitor U0126 were added to seek the possible regulatory mechanisms of Hsp47 expression.


RESULTS
A significantly higher percentage of cells positively stained for Hsp47 was noted in the cyclosporine A-induced gingival overgrowth group than in the normal gingival group (p < 0.05). Expression of Hsp47 was observed mainly in the cytoplasm of fibroblasts, endothelial cells, epithelial cells and inflammatory cells. Expression of Hsp47 was significantly higher in cyclosporine A-induced gingival overgrowth specimens with higher levels of inflammatory infiltrates (p < 0.05). Cyclosporine A upregulated Hsp47 expression in human gingival fibroblasts in a dose-dependent manner (p < 0.05). The addition of A. actinomycetemcomitans or interleukin-1 alpha significantly increased Hsp47 expression compared with cyclosporine A alone (p < 0.05). The MEK inhibitor U0126 was found to inhibit cyclosporine A-induced Hsp47 expression (p < 0.05).


CONCLUSIONS
Expression of Hsp47 is significantly upregulated in cyclosporine A-induced gingival overgrowth specimens, and Hsp47 expression induced by cyclosporine A in fibroblasts may be mediated by the MEK signal transduction pathway. The expression of Hsp47 could be significantly enhanced by A. actinomycetemcomitans and interleukin-1 alpha.
Chang
T-Y
TY
Graduate School of Dentistry, Chung Shan Medical University, Taichung, Taiwan.
Tsai
C-H
CH
Chang
Y-C
YC
D016976:Aggregatibacter actinomycetemcomitans / Q000502:physiology; D015153:Blotting, Western; D002070:Butadienes / Q000494:pharmacology; D002478:Cells, Cultured; D016572:Cyclosporine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects; D005881:Gingiva / Q000166:cytology / Q000187:drug effects*; D019214:Gingival Overgrowth / Q000473:pathology / Q000503:physiopathology; D050958:HSP47 Heat-Shock Proteins / Q000032:analysis / Q000037:antagonists & inhibitors / Q000187:drug effects*; D006801:Humans; D007150:Immunohistochemistry; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D007249:Inflammation; D053582:Interleukin-1alpha / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors; D009570:Nitriles / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects*
D002070:Butadienes; D004791:Enzyme Inhibitors; D050958:HSP47 Heat-Shock Proteins; D007166:Immunosuppressive Agents; D053582:Interleukin-1alpha; D009570:Nitriles; C494660:SERPINH1 protein, human; C113580:U 0126; D016572:Cyclosporine; D020929:Mitogen-Activated Protein Kinase Kinases