title: Inhibitory effects of alternaramide on inflammatory mediator expression through TLR4-MyD88-mediated inhibition of NF-кB and MAPK pathway signaling in lipopolysaccharide-stimulated RAW264.7 and BV2 cells.
abstract: Alternaramide (1), a novel lipophilic depsipeptide, has been isolated from the extract of the marine-derived fungus Alternaria sp. SF-5016. In the course of extensive biological evaluation of 1, its anti-inflammatory effects in lipopolysaccharide (LPS)-stimulated RAW264.7 and BV2 cells were observed. In our initial study of the anti-inflammatory effects of 1, the compound suppressed production of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-stimulated RAW264.7 and BV2 cells. Suppression of NO and PGE2 production was correlated with the inhibitory effect of 1 on expression of LPS-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the protein level in RAW264.7 and BV2 cells. In addition, 1 reduced production of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and IL-12 in LPS-stimulated RAW264.7 and BV2 cells. In the evaluation of the molecular mechanisms underlying the anti-inflammatory effects of 1, the compound was found to suppress the nuclear factor-kappa B (NF-κB) signaling pathway in RAW264.7 and BV2 cells stimulated with LPS. This suppression was mediated by disruption of phosphorylation and degradation of IκBα, an inhibitor of NF-κB, in the cytoplasm, and blocking of nuclear translocation of the NF-κB p50-p65 heterodimer. Furthermore, 1 inhibited phosphorylation of c-Jun N-terminal kinases (JNKs) and p38 mitogen-activated protein kinase (MAPK), demonstrating its capacity to inhibit MAPK signaling. Finally, 1 markedly reduced expression of Toll-like receptor 4 (TLR4) and myeloid differentiation primary response gene 88 (MyD88) at the mRNA and protein levels in LPS-stimulated RAW264.7 and BV2 cells. Taken together, the results of the present study suggest that 1 modulates several TLR4-mediated inflammatory pathways, demonstrating its potential in the treatment of inflammatory and neuroinflammatory conditions.
authors.affiliation: College of Pharmacy, Wonkwang University, Iksan 570-749, Republic of Korea.
authors.forename: Wonmin
authors.initials: W
authors.lastname: Ko
authors.affiliation: College of Medical and Life Sciences, Silla University, Busan 617-736, Republic of Korea.
authors.forename: Jae Hak
authors.initials: JH
authors.lastname: Sohn
authors.affiliation: Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongwon, Republic of Korea.
authors.forename: Jae-Hyuk
authors.initials: JH
authors.lastname: Jang
authors.affiliation: Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongwon, Republic of Korea.
authors.forename: Jong Seog
authors.initials: JS
authors.lastname: Ahn
authors.affiliation: Hanbang Body-Fluid Research Center, Wonkwang University, Iksan 570-749, Republic of Korea.
authors.forename: Dae Gill
authors.initials: DG
authors.lastname: Kang
authors.affiliation: Hanbang Body-Fluid Research Center, Wonkwang University, Iksan 570-749, Republic of Korea.
authors.forename: Ho Sub
authors.initials: HS
authors.lastname: Lee
authors.affiliation: College of Pharmacy, Wonkwang University, Iksan 570-749, Republic of Korea.
authors.forename: Jong-Su
authors.initials: JS
authors.lastname: Kim
authors.affiliation: College of Pharmacy, Wonkwang University, Iksan 570-749, Republic of Korea. Electronic address: yckim@wku.ac.kr.
authors.forename: Youn-Chul
authors.initials: YC
authors.lastname: Kim
authors.affiliation: College of Pharmacy, Wonkwang University, Iksan 570-749, Republic of Korea. Electronic address: hoh@wku.ac.kr.
authors.forename: Hyuncheol
authors.initials: H
authors.lastname: Oh
mesh_terms: D000528:Alternaria / Q000737:chemistry; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002460:Cell Line; D047630:Depsipeptides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D051379:Mice; D008968:Molecular Conformation; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D013329:Structure-Activity Relationship; D051197:Toll-Like Receptor 4 / Q000096:biosynthesis / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D047630:Depsipeptides; D008070:Lipopolysaccharides; C507779:MYD88 protein, human; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; C495345:TLR4 protein, human; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; C545596:alternaramide; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases
keywords: Alternaramide; Anti-inflammation; MAPK; Marine-derived fungus; Nuclear factor-kappa B; Toll-like receptor 4