title: Inhibitory effects of dynorphin 3-14 on the lipopolysaccharide-induced toll-like receptor 4 signalling pathway.
abstract: Dynorphin 1-17 (DYN 1-17) is biotransformed rapidly to a range of fragments in rodent inflamed tissue with dynorphin 3-14 (DYN 3-14) being the most stable and prevalent. DYN 1-17 has been shown previously to be involved in the regulation of inflammatory response following tissue injury, in which the biotransformation fragments of DYN 1-17 may possess similar features. This study investigated the effects of DYN 3-14 on lipopolysaccharide (LPS)-induced nuclear factor-kappaB/p65 (NF-κB/p65) nuclear translocation and the release of pro-inflammatory cytokines interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) in differentiated THP-1 cells. Treatment with DYN 3-14 (10nM) resulted in 35% inhibition of the LPS-induced nuclear translocation of NF-κB/p65. Furthermore, DYN 3-14 modulated both IL-1β and TNF-α release; inhibiting IL-1β and paradoxically augmenting TNF-α release in a concentration-independent manner. A number of opioids have been implicated in the modulation of the toll-like receptor 4 (TLR4), highlighting the complexity of their immunomodulatory effects. To determine whether DYN 3-14 modulates TLR4, HEK-Blue™-hTLR4 cells were stimulated with LPS in the presence of DYN 3-14. DYN 3-14 (10μM) inhibited TLR4 activation in a concentration-dependent fashion by suppressing the LPS signals around 300-fold lower than LPS-RS, a potent TLR4 antagonist. These findings indicate that DYN 3-14 is a potential TLR4 antagonist that alters cellular signaling in response to LPS and cytokine release, implicating a role for biotransformed endogenous opioid peptides in immunomodulation.
authors.affiliation: School of Pharmacy, The University of Queensland, Woolloongabba 4102, QLD, Australia; School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden 11800, Penang, Malaysia.
authors.forename: Siti Sarah Fazalul
authors.initials: SSF
authors.lastname: Rahiman
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, St Lucia 4072, QLD, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Morgan
authors.affiliation: School of Medicine, The University of Queensland, Herston 4006, QLD, Australia; Department of Anaesthesia, Princess Alexandra Hospital, Woolloongabba 4102, QLD, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Gray
authors.affiliation: School of Pharmacy, The University of Queensland, Woolloongabba 4102, QLD, Australia.
authors.forename: Paul Nicholas
authors.initials: PN
authors.lastname: Shaw
authors.affiliation: School of Pharmacy, The University of Queensland, Woolloongabba 4102, QLD, Australia. Electronic address: p.cabot@uq.edu.au.
authors.forename: Peter John
authors.initials: PJ
authors.lastname: Cabot
mesh_terms: D000818:Animals; D002460:Cell Line; D004399:Dynorphins / Q000008:administration & dosage* / Q000276:immunology; D006801:Humans; D056747:Immunomodulation / Q000187:drug effects; D007249:Inflammation / Q000139:chemically induced / Q000188:drug therapy* / Q000235:genetics; D053583:Interleukin-1beta / Q000235:genetics; D008070:Lipopolysaccharides / Q000633:toxicity; D016328:NF-kappa B / Q000235:genetics; D021381:Protein Transport / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D051197:Toll-Like Receptor 4 / Q000037:antagonists & inhibitors / Q000235:genetics*; D051996:Transcription Factor RelA / Q000235:genetics*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
chemical_list: D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D016328:NF-kappa B; C498143:RELA protein, human; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D004399:Dynorphins
keywords: B/p65; Dynorphin; IL-1β; LPS; NF-κ; TLR4; TNF-α