Transforming growth factor β1 enhances heme oxygenase 1 expression in human synovial fibroblasts by inhibiting microRNA 519b synthesis.

Shu-Jui Kuo,Wei-Hung Yang,Chun-Hao Tsai,Chih-Hsin Tang,Shan-Chi Liu,Horng-Chaung Hsu,Chuen-Mao Yang

doi:10.1371/journal.pone.0176052

Abstract

BackgroundOsteoarthritis (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 findingsTGF-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/SignificanceTGF-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.

Highlights

Osteoarthritis (OA) is manifested by synovial inflammation and cartilage destruction that correlates with synovitis, joint swelling and pain
We found that TGF-β1 (0 to 30 ng/ml) stimulated the synthesis of Heme oxygenase 1 (HO-1) protein by osteoarthritic synovial fibroblasts (OASFs) in a concentration-dependent manner (Fig 1A and 1B)
When we treated OASFs with TGF-β1 (10 ng/ml) for 0 to 24 hours, we found that TGF-β1 stimulated the synthesis of HO-1 protein in a time-dependent manner under the Western blotting and ELISA assay (Fig 2A and 2B)

Summary

Introduction

Osteoarthritis (OA) is manifested by synovial inflammation and cartilage destruction that correlates with synovitis, joint swelling and pain. The pro-inflammatory and catabolic mediators synthesized by the inflamed synovium led to the excessive synthesis of the proteolytic enzymes that are responsible for cartilage destruction. In the light of the role of synovium in the pathogenesis and the symptoms of OA, synovium-targeted therapy may potentially halt the progression of structural destruction and mitigate the symptoms of the disease [3]. 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. 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

Methods

Results

Conclusion