title: Clock gene expression in different synovial cells of patients with rheumatoid arthritis and osteoarthritis.
abstract: Patients with rheumatoid arthritis (RA) show modulated circadian rhythms of inflammatory cytokines and cortisol, which may be associated with a modified expression of clock genes. The expression of major clock genes was previously studied in synovial tissues and fibroblasts of patients with RA and osteoarthritis (OA). We therefore especially aimed to examine the localization of clock genes at the cellular level in synovial tissue. Furthermore we were interested in studying the expression of the D site of albumin promoter (albumin D-box) binding protein (DBP) at the immunohistochemical level in human samples. Methods used include the in situ expression of the clock genes Brain and muscle aryl hydrocarbon receptor nuclear translocator-like 1 (Bmal 1), Circadian Locomotor Output Cycles Kaput (Clock), Period 1 and 2 (Per 1 and Per 2), and DBP was examined by immunohistochemistry in synovial tissues of patients with RA or OA. Additionally, expression profiles of different clock genes were determined over 24h by real time PCR in synovial fibroblasts (SFs) after a 2h serum shock or TNF-α. Results show that all clock genes investigated were found to be expressed both in RA and OA synovial tissues. Double staining against cell specific markers revealed that clock proteins were especially seen in macrophages, SFs and B-lymphocytes. Cell counting showed that clock proteins were found in approximately 5-20% of cells. Additionally, preliminary cell culture experiments showed that TNF-α treatment resulted in differential 24h expression profiles between RA and OA samples and also compared to the results obtained from the serum shock experiments. From our study we conclude that the major clock genes, including DBP, are expressed in samples from RA and OA patients, especially in macrophages and synovial fibroblasts, but also in B-lymphocytes. Preliminary experiments suggest that TNF-α seems to be able to modify clock gene expression in synovial fibroblasts.
authors.affiliation: Ludwig Boltzmann Cluster for Rheumatology, Balneology and Rehabilitation, Vienna, Austria.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Becker
authors.affiliation: Ludwig Boltzmann Cluster for Rheumatology, Balneology and Rehabilitation, Vienna, Austria.
authors.forename: Makiyeh
authors.initials: M
authors.lastname: Tohidast-Akrad
authors.affiliation: Ludwig Boltzmann Cluster for Rheumatology, Balneology and Rehabilitation, Vienna, Austria; Institute of Physiology, Medical University Vienna, Austria.
authors.forename: Susanne
authors.initials: S
authors.lastname: Humpeler
authors.affiliation: Department of Experimental Immunology, Academic Medical Center, Amsterdam, Netherlands; GSK, GlaxoSmithKline, Cambridge, UK.
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Gerlag
authors.affiliation: Division of Rheumatology, Department of Internal Medicine III, Medical University of Vienna, Austria.
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Kiener
authors.affiliation: Orthopedic Centre, Otto-Wagner-Spital, Vienna, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Zenz
authors.affiliation: Ludwig Boltzmann Cluster for Rheumatology, Balneology and Rehabilitation, Vienna, Austria; Division of Rheumatology, Department of Internal Medicine III, Medical University of Vienna, Austria.
authors.forename: Günter
authors.initials: G
authors.lastname: Steiner
authors.affiliation: Ludwig Boltzmann Cluster for Rheumatology, Balneology and Rehabilitation, Vienna, Austria; Institute of Environmental Health, Centre for Public Health, Medical University of Vienna, Austria. Electronic address: cem.ekmekcioglu@meduniwien.ac.at.
authors.forename: Cem
authors.initials: C
authors.lastname: Ekmekcioglu
mesh_terms: D001172:Arthritis, Rheumatoid / Q000378:metabolism* / Q000473:pathology; D002478:Cells, Cultured; D056925:Circadian Rhythm Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D008264:Macrophages / Q000378:metabolism; D010003:Osteoarthritis / Q000378:metabolism* / Q000473:pathology; D013582:Synovial Fluid / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology
chemical_list: D056925:Circadian Rhythm Signaling Peptides and Proteins; C439524:TNF protein, human; D014409:Tumor Necrosis Factor-alpha
keywords: Clock genes; Immunohistochemistry; Osteoarthritis; Rheumatoid arthritis; Synovial fibroblasts; Synovial tissue