title: Sparstolonin B attenuates early liver inflammation in experimental NASH by modulating TLR4 trafficking in lipid rafts via NADPH oxidase activation.
abstract: Although significant research data exist on the pathophysiology of nonalcoholic steatohepatitis (NASH), finding an efficient treatment regimen for it remains elusive. The present study used sparstolonin B (SsnB), a novel TLR4 antagonist derived from the Chinese herb Sparganium stoloniferum, as a possible drug to mitigate early inflammation in NASH. This study used an early steatohepatitic injury model in high-fat-fed mice with CYP2E1-mediated oxidative stress as a second hit. SsnB was administered for 1 wk along with bromodichloromethane (BDCM), an inducer of CYP2E1-mediated oxidative stress. Results showed that SsnB administration attenuated inflammatory morphology and decreased elevation of the liver enzyme alanine aminotransferase (ALT). Mice administered SsnB also showed decreased mRNA expression of proinflammatory cytokines TNF-α, IFN-γ, IL-1β, and IL-23, while protein levels of both TNF-α and IL-1β were significantly decreased. SsnB significantly decreased Kupffer cell activation as evidenced by reduction in CD68 and monocyte chemoattractant protein-1 (MCP1) mRNA and protein levels with concomitant inhibition of macrophage infiltration in the injured liver. Mechanistically, SsnB decreased TLR4 trafficking to the lipid rafts, a phenomenon described by the colocalization of TLR4 and lipid raft marker flotillin in tissues and immortalized Kupffer cells. Since we have shown previously that NADPH oxidase drives TLR4 trafficking in NASH, we studied the role of SsnB in modulating this pathway. SsnB prevented NADPH oxidase activation in vivo and in vitro as indicated by decreased peroxynitrite formation. In summary, the present study reports a novel use of the TLR4 antagonist SsnB in mitigating inflammation in NASH and in parallel shows a unique molecular mechanism of decreasing nitrative stress.
authors.affiliation: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina;
authors.forename: Diptadip
authors.initials: D
authors.lastname: Dattaroy
authors.affiliation: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina;
authors.forename: Ratanesh Kumar
authors.initials: RK
authors.lastname: Seth
authors.affiliation: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina;
authors.forename: Suvarthi
authors.initials: S
authors.lastname: Das
authors.affiliation: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina;
authors.forename: Firas
authors.initials: F
authors.lastname: Alhasson
authors.affiliation: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina;
authors.forename: Varun
authors.initials: V
authors.lastname: Chandrashekaran
authors.affiliation: Division of Gastroenterology, Duke University, Durham, North Carolina;
authors.forename: Gregory
authors.initials: G
authors.lastname: Michelotti
authors.affiliation: Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, South Carolina; and.
authors.forename: Daping
authors.initials: D
authors.lastname: Fan
authors.affiliation: Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina.
authors.forename: Mitzi
authors.initials: M
authors.lastname: Nagarkatti
authors.affiliation: Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina.
authors.forename: Prakash
authors.initials: P
authors.lastname: Nagarkatti
authors.affiliation: Division of Gastroenterology, Duke University, Durham, North Carolina;
authors.forename: Anna Mae
authors.initials: AM
authors.lastname: Diehl
authors.affiliation: Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina; schatt@mailbox.sc.edu.
authors.forename: Saurabh
authors.initials: S
authors.lastname: Chatterjee
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002460:Cell Line; D019392:Cytochrome P-450 CYP2E1 / Q000096:biosynthesis; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D004789:Enzyme Activation; D004790:Enzyme Induction; D006505:Hepatitis / Q000201:enzymology / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D006576:Heterocyclic Compounds, 4 or More Rings / Q000494:pharmacology*; D018836:Inflammation Mediators / Q000378:metabolism; D007728:Kupffer Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008099:Liver / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology; D008297:Male; D021962:Membrane Microdomains / Q000187:drug effects* / Q000201:enzymology; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D019255:NADPH Oxidases / Q000378:metabolism*; D065626:Non-alcoholic Fatty Liver Disease / Q000201:enzymology / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D018384:Oxidative Stress / Q000187:drug effects; D051059:PTEN Phosphohydrolase / Q000378:metabolism; D030421:Peroxynitrous Acid / Q000378:metabolism; D021381:Protein Transport; D015398:Signal Transduction / Q000187:drug effects; D051197:Toll-Like Receptor 4 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
chemical_list: D000893:Anti-Inflammatory Agents; D016207:Cytokines; D006576:Heterocyclic Compounds, 4 or More Rings; D018836:Inflammation Mediators; C531950:MIRN21 microRNA, mouse; D008565:Membrane Proteins; D035683:MicroRNAs; C493487:Tlr4 protein, mouse; C495347:Tlr4 protein, rat; D051197:Toll-Like Receptor 4; C106354:flotillins; C561322:sparstolonin B; D030421:Peroxynitrous Acid; D019392:Cytochrome P-450 CYP2E1; D019255:NADPH Oxidases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human
keywords: NADPH oxidase; SsnB; inflammation; p47phox; peroxynitrite