title: Aciculatin inhibits granulocyte colony-stimulating factor production by human interleukin 1β-stimulated fibroblast-like synoviocytes.
abstract: The expression of granulocyte colony-stimulating factor (G-CSF), the major regulator of neutrophil maturation, by human fibroblast-like synoviocytes (FLS) can be stimulated by the inflammatory cytokine interleukin-1β (IL-1β). G-CSF is known to contribute to the pathologic processes of destructive arthritis, but the induction mechanism remains unknown. The aims of this study were to identify the signaling pathways involved in IL-1β-stimulated G-CSF production and to determine whether this process was inhibited by aciculatin (8-((2R,4S,5S,6R)-tetrahydro-4,5-dihydroxy-6-methyl-2H-pyran-2-yl)-5-hydroxy-2-(4-hydroxyphenyl)-7-methoxy-4H-chromen-4-one), the major bioactive component of Chrysopogon aciculatus. IL-1β-induced cytokine expression was evaluated by measuring mRNA and protein levels by RT-PCR, ELISA, and Milliplex® assay. Whether aciculatin inhibited IL-1β-stimulated G-CSF expression, and if so, how, were evaluated using western blot assay, an electrophoretic mobility shift assay, and a reporter gene assay. Neutrophil differentiation was determined by Wright-Giemsa staining and flow cytometry. Aciculatin markedly inhibited G-CSF expression induced by IL-1β (10 ng/mL) in a concentration-dependent manner (1-10 µM). In clarifying the mechanisms involved, aciculatin was found to inhibit the IL-1β-induced activation of the IκB kinase (IKK)/IκB/nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways by suppressing the DNA binding activity of the transcription factors NF-κB and activator protein (AP)-1. Furthermore, aciculatin significantly inhibited the G-CSF-mediated phosphorylation of Janus kinase-signal transducer and activator of transcription (JAK-STAT) and Akt and neutrophil differentiation from precursor cells. Our results show that aciculatin inhibits IL-1β-stimulated G-CSF expression and the subsequent neutrophil differentiation, suggesting that it might have therapeutic potential for inflammatory arthritis.
authors.affiliation: Orthopedic Department, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
authors.forename: Kao-Shang
authors.initials: KS
authors.lastname: Shih
authors.forename: Jyh-Horng
authors.initials: JH
authors.lastname: Wang
authors.forename: Yi-Wen
authors.initials: YW
authors.lastname: Wu
authors.forename: Che-Ming
authors.initials: CM
authors.lastname: Teng
authors.forename: Chien-Chih
authors.initials: CC
authors.lastname: Chen
authors.forename: Chia-Ron
authors.initials: CR
authors.lastname: Yang
mesh_terms: D024202:Electrophoretic Mobility Shift Assay; D004797:Enzyme-Linked Immunosorbent Assay; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D005419:Flavonoids / Q000494:pharmacology*; D005434:Flow Cytometry; D016179:Granulocyte Colony-Stimulating Factor / Q000096:biosynthesis*; D006801:Humans; D053583:Interleukin-1beta / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D013583:Synovial Membrane / Q000166:cytology / Q000187:drug effects*
chemical_list: D005419:Flavonoids; D053583:Interleukin-1beta; C074400:aciculatin; D016179:Granulocyte Colony-Stimulating Factor