title: Parthenolide inhibits LPS-induced inflammatory cytokines through the toll-like receptor 4 signal pathway in THP-1 cells.
abstract: Parthenolide (PTL) shows potent anti-inflammatory and anti-cancer activities. In the present study, the molecular mechanisms of PTL's activities were explored in lipopolysaccharide (LPS)-induced human leukemia monocytic THP-1 cells and human primary monocytes. The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium salt (MTS) assay was used to analyze the effect of PTL on THP-1 cell viability. Enzyme-linked immunosorbent assay was used to determine the effect of PTL on LPS-induced inflammatory cytokine secretion. Flow cytometry and quantitative real-time polymerase chain reaction were used to assess the effect of PTL on LPS-induced toll-like receptor 4 (TLR4) expression. Phosphorylation levels of signaling molecules were determined by western blot analysis. Results showed that PTL <12.5 μM did not significantly affect THP-1 cells viability. LPS treatment led to a marked up-regulation of interleukin (IL)-6, IL-1β, IL-8, IL-12p40, tumor necrosis factor-α, IL-18, and NO in THP-1 cells. However, PTL inhibited the expression of these cytokines in a dose-dependent manner, with IC50 values of 1.091-2.620 μM. PTL blocked TLR4 expression with an IC50 value of 1.373 μM as determined by the flow cytometry analysis, and this blocking effect was verified at both protein and mRNA levels. Up-regulation of phosphorylation levels of extracellular signal-regulated kinase 1/2, Jun N-terminal kinase, p38, nuclear factor κB (NF-κB) p65, and IκBα and up-regulation of expressions of other molecules (inducible nitric oxide synthase, TLR4, and TNF receptor-associated factor 6) induced by LPS were abolished by PTL in a dose-dependent manner. The anti-inflammatory mechanisms of PTL operate partly through the TLR4-mediated mitogen-activated protein kinase and NF-κB signaling pathways. Therefore, TLR4 may be a new target for anti-inflammation therapies.
authors.affiliation: Department of Hematology, First Affiliated Hospital, Zhejiang University College of Medicine, Hangzhou 310003, China Department of Hematology, Zhejiang Provincial People's Hospital, Hangzhou 310003, China.
authors.forename: Shuangshuang
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Hematology, First Affiliated Hospital, Zhejiang University College of Medicine, Hangzhou 310003, China.
authors.forename: Xiangli
authors.initials: X
authors.lastname: Gao
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, Zhejiang University College of Medicine, Hangzhou 310003, China.
authors.forename: Xiaoxin
authors.initials: X
authors.lastname: Wu
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, Zhejiang University College of Medicine, Hangzhou 310003, China.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Wu
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, Zhejiang University College of Medicine, Hangzhou 310003, China.
authors.forename: Linfang
authors.initials: L
authors.lastname: Cheng
authors.affiliation: Department of Hematology, First Affiliated Hospital, Zhejiang University College of Medicine, Hangzhou 310003, China.
authors.forename: Lifen
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Department of Hematology, First Affiliated Hospital, Zhejiang University College of Medicine, Hangzhou 310003, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Shen
authors.affiliation: Department of Hematology, First Affiliated Hospital, Zhejiang University College of Medicine, Hangzhou 310003, China Department of Hematology, Zhejiang Provincial People's Hospital, Hangzhou 310003, China tongxiangmin11@163.com.
authors.forename: Xiangmin
authors.initials: X
authors.lastname: Tong
mesh_terms: D002460:Cell Line; D016207:Cytokines / Q000378:metabolism*; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D012717:Sesquiterpenes / Q000494:pharmacology*; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000378:metabolism*
chemical_list: D016207:Cytokines; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D012717:Sesquiterpenes; D051197:Toll-Like Receptor 4; C002669:parthenolide
keywords: MAPK; TLR4; anti-inflammation; inflammatory cytokine; parthenolide