title: Proinflammatory cytokine gene expression by murine macrophages in response to Brugia malayi Wolbachia surface protein.
abstract: Wolbachia, an endosymbiotic bacterium found in most species of filarial parasites, is thought to play a significant role in inducing innate inflammatory responses in lymphatic filariasis patients. However, the Wolbachia-derived molecules that are recognized by the innate immune system have not yet been identified. In this study, we exposed the murine macrophage cell line RAW 264.7 to a recombinant form of the major Wolbachia surface protein (rWSP) to determine if WSP is capable of innately inducing cytokine transcription. Interleukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF) mRNAs were all upregulated by the rWSP stimulation in a dose-dependant manner. TNF transcription peaked at 3 hours, whereas IL-1beta and IL-6 transcription peaked at 6 hours post-rWSP exposure. The levels of innate cytokine expression induced by a high-dose (9.0 microg/mL) rWSP in the RAW 264.7 cells were comparable to the levels induced by 0.1 microg/mL E. coli-derived lipopolysaccharides. Pretreatment of the rWSP with proteinase-K drastically reduced IL-1beta, IL-6, and TNF transcription. However, the proinflammatory response was not inhibited by polymyxin B treatment. These results strongly suggest that the major Wolbachia surface protein molecule WSP is an important inducer of innate immune responses during filarial infections.
authors.affiliation: Lymphatic Filariasis Research Unit, Department of Parasitology, and Chulalongkorn Medical Research Center, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Chantima
authors.initials: C
authors.lastname: Porksakorn
authors.forename: Surang
authors.initials: S
authors.lastname: Nuchprayoon
authors.forename: Kiwon
authors.initials: K
authors.lastname: Park
authors.forename: Alan L
authors.initials: AL
authors.lastname: Scott
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D017178:Brugia malayi / Q000382:microbiology; D002460:Cell Line; D016207:Cytokines / Q000235:genetics*; D015870:Gene Expression / Q000187:drug effects*; D053583:Interleukin-1beta / Q000235:genetics; D015850:Interleukin-6 / Q000235:genetics; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics; D020577:Wolbachia / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D016207:Cytokines; D053583:Interleukin-1beta; D015850:Interleukin-6; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha