Abstract
Background:
Osteoarthritis (OA) is manifested by synovial inflammation and cartilage destruction that is directly linked to synovitis, joint swelling and pain. In the light of the role of synovium in the pathogenesis and the symptoms of OA, synovium-targeted therapy is a promising strategy to mitigate the symptoms and progression of OA. Transforming growth factor beta 1 (TGF-β1), a secreted homodimeric protein, possesses unique and potent anti-inflammatory and immune-regulatory properties in many cell types. Heme oxygenase 1 (HO-1) is an inducible anti-inflammatory and stress responsive enzyme that has been proven to prevent injuries caused by many diseases. Despite the similar anti-inflammatory profile and their involvement in the pathogenesis of arthritic diseases, no studies have as yet explored the possibility of any association between the expression of TGF-β1 and HO-1.
Methodology/principal findings:
TGF-β1-induced HO-1 expression was examined by HO-1 promoter assay, qPCR, and Western blotting. The siRNAs and enzyme inhibitors were utilized to determine the intermediate involved in the signal transduction pathway. We showed that TGF-β1 stimulated the synthesis of HO-1 in a concentration- and time-dependent manner, which can be mitigated by blockade of the phospholipase (PLC)γ/protein kinase C alpha (PKC)α pathway. We also showed that the expression of miRNA-519b, which blocks HO-1 transcription, is inhibited by TGF-β1, and the suppression of miRNA 519b could be reversed via blockade of the PLCγ/PKCα pathway.
Conclusions/significance:
TGF-β1 stimulated the expression of HO-1 via activating the PLCγ/PKCα pathway and suppressing the downstream expression of miRNA-519b. These results may shed light on the pathogenesis and treatment of OA.
MeSH terms
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Antibodies / pharmacology
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Arthroplasty, Replacement, Knee
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Carbazoles / pharmacology
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Cartilage, Articular / drug effects
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Cartilage, Articular / metabolism
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Cartilage, Articular / pathology
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Enzyme Inhibitors / pharmacology
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Fibroblasts / drug effects
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Fibroblasts / metabolism*
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Fibroblasts / pathology
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Gene Expression Regulation
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Heme Oxygenase-1 / genetics*
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Heme Oxygenase-1 / metabolism
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Humans
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Indoles / pharmacology
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Maleimides / pharmacology
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MicroRNAs / genetics*
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MicroRNAs / metabolism
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Osteoarthritis / genetics*
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Osteoarthritis / metabolism
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Osteoarthritis / pathology
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Osteoarthritis / surgery
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Phospholipases / antagonists & inhibitors
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Phospholipases / genetics
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Phospholipases / metabolism
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Primary Cell Culture
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Protein Kinase C-alpha / antagonists & inhibitors
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Protein Kinase C-alpha / genetics
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Protein Kinase C-alpha / metabolism
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RNA, Small Interfering / genetics
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RNA, Small Interfering / metabolism
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
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Recombinant Proteins / pharmacology
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Signal Transduction
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Synovial Membrane / drug effects
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Synovial Membrane / metabolism
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Synovial Membrane / pathology
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Transforming Growth Factor beta1 / genetics*
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Transforming Growth Factor beta1 / metabolism
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Transforming Growth Factor beta1 / pharmacology
Substances
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Antibodies
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Carbazoles
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Enzyme Inhibitors
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Indoles
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MIRN519 microRNA, human
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Maleimides
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MicroRNAs
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RNA, Small Interfering
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Recombinant Proteins
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TGFB1 protein, human
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Transforming Growth Factor beta1
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Go 6976
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HMOX1 protein, human
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Heme Oxygenase-1
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Protein Kinase C-alpha
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Phospholipases
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bisindolylmaleimide I
Grants and funding
This work was supported by grants from the Ministry of Science and Technology of Taiwan (MOST 103-2628-B-039-002-MY3; MOST 105-2320-B-039-015-MY3; MOST 105-2811-B-039-014), China Medical University, Taiwan (CMU 103-S-06) and in part from the grant from Chinese Medicine Research Center, China Medical University (the Ministry of Education, the Aim for the Top University Plan).