TGF-beta induced hyaluronan synthesis in orbital fibroblasts involves protein kinase C betaII activation in vitro.
Graves' ophthalmopathy is accompanied by hyaluronan (HA) accumulation in the orbital space and infiltration of immunocompetent cells and cytokines, including IFN-gamma, IL-1beta, and TGF-beta. We examined the signal transduction pathways by which TGF-beta induces HA synthesis in normal orbital fibroblasts, orbital fibroblasts from patients with Graves' ophthalmopathy, and abdominal fibroblasts. Calphostin C inhibited the stimulation of HA synthesis by TGF-beta. Phorbol 12-myristate 13-acetate (PMA) activation of PKC stimulated HA production. The effects of TGF-beta and PMA were not synergistic. Stimulation by TGF-beta and PMA were dependent on protein synthesis and their effects were inhibited by cycloheximide. Since TGF-beta-induced HA synthesis was inhibited by BAPTA or by PKC inhibitors, a calcium-dependent PKC was most likely involved. The PKA inhibitor H-89 enhanced TGF-beta- and PMA-induced HA synthesis, thus showing that communication between the PKA and PKC pathways was evident. TGF-beta stimulated the translocation of PKCbetaII to the cell membrane. PKCbetaII, a key enzyme in the regulation of HA synthesis by TGF-beta, might be an appropriate target for therapeutic compounds to be used to treat Graves' ophthalmopathy accompanied by inflammation.
Wang
Hwai-Shi
HS
Institute of Anatomy and Cell Biology, School of Medicine, Yang-Ming University, Taipei, Taiwan. hswang@ym.edu.tw
Tung
Wen-Hsiu
WH
Tang
Kam-Tsun
KT
Wong
Yi-Kuei
YK
Huang
Ging-Jye
GJ
Wu
Jiahn-Chun
JC
Guo
Yi-Jhih
YJ
Chen
Chin-Chang
CC
D001483:Base Sequence; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D017931:DNA Primers; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D014453:Glucuronosyltransferase / Q000378:metabolism; D006801:Humans; D000076002:Hyaluronan Synthases; D006820:Hyaluronic Acid / Q000096:biosynthesis*; D007150:Immunohistochemistry; D009281:Naphthalenes / Q000494:pharmacology; D009915:Orbit / Q000166:cytology / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D064546:Protein Kinase C beta; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000502:physiology*
D017931:DNA Primers; D004791:Enzyme Inhibitors; D009281:Naphthalenes; D016212:Transforming Growth Factor beta; D006820:Hyaluronic Acid; D014453:Glucuronosyltransferase; D000076002:Hyaluronan Synthases; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D064546:Protein Kinase C beta; C058819:calphostin C; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium