imd-0354 and Arthritis--Rheumatoid

Patients with rheumatoid arthritis (RA) have altered circadian rhythm of circulating serum cortisol, melatonin and IL-6, as well as disturbance in the expression of clock genes ARNTL2 and NPAS2. In humans, TNFα increases the expression ARNTL2 and NPAS2 but paradoxically suppresses clock output genes DPB and PER3. Our objective was to investigate the expression of direct clock suppressors DEC1 and DEC2 (BHLHE 40 and 41 proteins) in response to TNFα and investigate their role during inflammation.. Cultured primary fibroblasts were stimulated with TNFα. Effects on DEC2 were studied using RT-qPCR and immunofluorescence staining. The role of NF-κB in DEC2 increase was analyzed using IKK-2 specific inhibitor IMD-0354. Cloned DEC2 was transfected into HEK293 cells to study its effects on gene expression. Transfections into primary human fibroblasts were used to confirm the results. The presence of DEC2 was analyzed in (RA) and osteoarthritis (OA) synovial membranes by immunohistochemistry.. TNFα increased DEC2 mRNA and DEC2 was mainly detected at nuclei after the stimulus. The effects of TNFα on DEC2 expression were mediated via NF-κB. Overexpression, siRNA and promoter activity studies disclosed that DEC2 directly regulates IL-1β, in both HEK293 cells and primary human fibroblasts. DEC2 was increased in synovial membrane in RA compared to OA.. Not only ARNTL2 and NPAS2 but also DEC2 is regulated by TNFα in human fibroblasts. NF-κB mediates the effect on DEC2, which upregulates IL-1β. Circadian clock has a direct effect on inflammation in human fibroblasts.

Topics: ARNTL Transcription Factors; Arthritis, Rheumatoid; Basic Helix-Loop-Helix Transcription Factors; Benzamides; Cell Line; Fibroblasts; HEK293 Cells; Humans; I-kappa B Kinase; Interleukin-1beta; Nerve Tissue Proteins; NF-kappa B; Osteoarthritis; Promoter Regions, Genetic; RNA Interference; RNA, Messenger; RNA, Small Interfering; Synovial Membrane; Tumor Necrosis Factor-alpha; Tumor Suppressor Proteins

Activator protein 1 (AP-1) is a pivotal transcription factor that regulates a wide range of cellular processes including proliferation, apoptosis, differentiation, survival, cell migration, and transformation. Accumulating evidence supports that AP-1 plays an important role in several severe disorders including cancer, fibrosis, and organ injury, as well as inflammatory disorders such as asthma, psoriasis, and rheumatoid arthritis. AP-1 has emerged as an actively pursued drug discovery target over the past decade. Excitingly, a selective AP-1 inhibitor T-5224 (51) has been investigated in phase II human clinical trials. Nevertheless, no effective AP-1 inhibitors have yet been approved for clinical use. Despite significant advances achieved in understanding AP-1 biology and function, as well as the identification of small molecules modulating AP-1 associated signaling pathways, medicinal chemistry efforts remain an urgent need to yield selective and efficacious AP-1 inhibitors as a viable therapeutic strategy for human diseases.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Rheumatoid; Benzophenones; Biological Products; Humans; Inflammation; Isoxazoles; Maleimides; Molecular Targeted Therapy; Neoplasms; Organic Chemicals; Quinazolines; Signal Transduction; Small Molecule Libraries; Transcription Factor AP-1; Transcription Factors

Thymic stromal lymphopoietin (TSLP) is an interleukin (IL)-7-like cytokine produced by epithelial cells and triggers dendritic cell-mediated Th2 type allergic inflammatory responses. This study investigated whether Toll-like receptor (TLR) ligands, lipopolysaccharide (LPS) and poly-IC affect TSLP production in synovial fibroblasts. Enzyme-linked immunosorbent assay showed that LPS and poly-IC upregulated TSLP production in synovial fibroblasts obtained from patients with rheumatoid arthritis (RA) and osteoarthritis (OA). In addition, we found that nuclear factor (NF)-kappaB inhibitor IMD-0354, dexamethasone, and interferon (IFN)-gamma inhibited the LPS- and poly-IC-induced TSLP production in RA and OA synovial fibroblasts. Thus, LPS and poly-IC can upregulate TSLP via a NF-kappaB pathway in synovial fibroblasts, which is downregulated by dexamethasone and interferon (IFN)-gamma. The current findings suggest that TSLP may be involved in the pathophysiology of inflammatory arthritis as well as allergic disease.

Topics: Aged; Aged, 80 and over; Arthritis, Rheumatoid; Benzamides; Cell Survival; Cells, Cultured; Culture Media, Conditioned; Cytokines; Dexamethasone; Dose-Response Relationship, Drug; Female; Fibroblasts; Humans; Interferon-gamma; Ligands; Lipopolysaccharides; Male; NF-kappa B; Osteoarthritis, Knee; Poly I-C; Recombinant Proteins; Stromal Cells; Synovial Membrane; Thymic Stromal Lymphopoietin; Toll-Like Receptors; Up-Regulation