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Updated: May 7, 2026

Generation of Induced-pluripotent Stem Cells Using Fibroblast-like Synoviocytes Isolated from Joints of Rheumatoid Arthritis Patients
Published on: October 16, 2016
Leptin induces IL-6 expression through OBRl receptor signaling pathway in human synovial fibroblasts
Wei-Hung Yang1, Shan-Chi Liu, Chun-Hao Tsai
1Department of Orthopedic Surgery, Taichung Hospital, Department of Health Executive Yuan, Taichung, Taiwan ; Department of Nursing, National Taichung University of Science and Technology, Taichung, Taiwan ; School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan ; Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan.
Background:
Leptin, an adipocyte-secreted hormone that centrally regulates weight control, may exert proinflammatory effects in the joint, depending on the immune response. Leptin is abundantly expressed in osteoarthritis (OA) cartilage and synovium. However, the relationship between leptin and interleukin-6 (IL-6) in OA synovial fibroblasts (OASFs) remains obscure.
Methodology/Principal Findings:
Stimulation of OASFs with leptin induced IL-6 expression in a concentration- and time-dependent manner. OASFs expressed the long (OBRl) and short (OBRs) isoforms of the leptin receptor. However, OBRl, but not OBRs, antisense oligonucleotide (AS-ODN) abolished the leptin-mediated increase of IL-6 expression. Transfection with insulin receptor substrate (IRS)-1 siRNA decreased leptin-induced IL-6 production. In addition, pretreatment of cells with PI3K, Akt, or AP-1 inhibitor also inhibited the potentiating action of leptin. Leptin-induced AP-1 activation was inhibited by OBRl, IRS-1, PI3K, or Akt inhibitors and siRNAs.
Conclusions/Significance:
Our results showed that leptin activates the OBRl receptor, which in turn activates IRS-1, PI3K, Akt, and AP-1 pathway, leading to up-regulation of IL-6 expression.
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