title: Soyasaponin Bb inhibits the recruitment of toll-like receptor 4 (TLR4) into lipid rafts and its signaling pathway by suppressing the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent generation of reactive oxygen species.
abstract: We and others recently showed that soyasaponin Bb (SSBb ) inhibited lipopolysaccharide (LPS)-induced inflammation in macrophages. Since the recruitment of toll-like receptor 4 (TLR4) into lipid rafts is vital for LPS-initiated signaling, we investigated whether this process would be modulated by SSBb .
  
  
  
  By using sucrose gradient ultracentrifuge, we found that pretreatment of macrophages with SSBb inhibited LPS-induced recruitments of TLR4, myeloid differentiation primary response protein 88 (MyD88) and Toll/IL-1 receptor domain-containing adaptor inducing interferon-β (TRIF) into fractions enriched with lipid rafts marker flotillin-1. We also found SSBb decreased co-localization of TLR4 and lipid rafts by utilizing confocal immunofluorescence microscopy. Additionally, we observed that SSBb suppressed LPS-induced formation of TLR4/MyD88 and TLR4/TRIF complexes, production of pro-inflammatory molecules, and activation of nuclear factor kappa B (NF-κB). Furthermore, we found that these inhibitory effects of SSBb were associated with reduced reactive oxygen species (ROS) because pretreating cells with N-acetyl-L-cysteine and NADPH oxidase inhibitor diphenyleneiodonium (DPI) inhibited LPS-induced TLR4 recruitment into lipid rafts and NF-κB activation. SSBb also inhibited NADPH oxidase activation by blocking interaction between gp91(phox) and p47(phox) similarly as DPI.
  
  
  
  SSBb can inhibit TLR4 recruitment into lipid rafts and its signaling by suppressing the NADPH oxidase-dependent ROS generation.
authors.affiliation: Department of Nutrition and Food Hygiene, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, P. R. China.
authors.forename: Yajie
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Nutrition and Food Hygiene, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, P. R. China.
authors.forename: Fengping
authors.initials: F
authors.lastname: Chen
authors.affiliation: Department of Nutrition and Food Hygiene, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, P. R. China.
authors.forename: Jiading
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Nutrition and Food Hygiene, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, P. R. China.
authors.forename: Suqun
authors.initials: S
authors.lastname: Huang
authors.affiliation: Department of Nutrition and Food Hygiene, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, P. R. China.
authors.forename: Junbin
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Nutrition and Food Hygiene, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, P. R. China.
authors.forename: Jian
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Nutrition and Food Hygiene, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, P. R. China.
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.affiliation: Department of Nutrition and Food Hygiene, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, P. R. China.
authors.forename: Suxia
authors.initials: S
authors.lastname: Sun
authors.affiliation: Department of Nutrition and Food Hygiene, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, P. R. China.
authors.forename: Xinwei
authors.initials: X
authors.lastname: Chu
authors.affiliation: Department of Nutrition and Food Hygiene, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, P. R. China.
authors.forename: Longying
authors.initials: L
authors.lastname: Zha
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000111:Acetylcysteine / Q000037:antagonists & inhibitors / Q000378:metabolism; D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics / Q000378:metabolism; D000818:Animals; D004265:DNA Helicases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D007249:Inflammation / Q000139:chemically induced / Q000188:drug therapy; D008070:Lipopolysaccharides / Q000633:toxicity; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D021962:Membrane Microdomains / Q000187:drug effects*; D051379:Mice; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000378:metabolism; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D009861:Onium Compounds / Q000494:pharmacology; D000067996:RAW 264.7 Cells; D017382:Reactive Oxygen Species / Q000378:metabolism*; D011971:Receptors, Immunologic / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D012503:Saponins / Q000494:pharmacology*; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D000074183:ATPases Associated with Diverse Cellular Activities; D000111:Acetylcysteine; D033942:Adaptor Proteins, Vesicular Transport; D004265:DNA Helicases; D008070:Lipopolysaccharides; D053594:Myeloid Differentiation Factor 88; D019255:NADPH Oxidases; D016328:NF-kappa B; D009861:Onium Compounds; D017382:Reactive Oxygen Species; D011971:Receptors, Immunologic; D012503:Saponins; D051197:Toll-Like Receptor 4; C507780:Myd88 protein, mouse; C105949:Pirb protein, mouse; C476286:Ticam1 protein, mouse; C493487:Tlr4 protein, mouse; C000602851:soyasaponin Bb; C007517:diphenyleneiodonium; C518330:RUVBL2 protein, mouse
keywords: Lipid raft/ Nicotinamide adenine dinucleotide phosphate/ Reactive oxygen species/ Soyasaponin/ Toll-like receptor 4