title: Inhibitory effect of ent-Sauchinone on amyloidogenesis via inhibition of STAT3-mediated NF-κB activation in cultured astrocytes and microglial BV-2 cells.
abstract: BACKGROUND
  ent-Sauchinone is a polyphenolic compound found in plants belonging to the lignan family. ent-Sauchinone has been shown to modulate the expression of inflammatory factors through the nuclear factor-kappa B (NF-κB) signaling pathway. It is well known that neuroinflammation is associated with amyloidogenesis. Thus, in the present study, we investigated whether ent-Sauchinone could have anti-amyloidogenic effects through the inhibition of NF-κB pathways via its anti-inflammatory property.
  
  
  METHODS
  To investigate the potential effect of ent-Sauchinone on anti-neuroinflammation and anti-amyloidogenesis in in vitro studies, we used microglial BV-2 cells and cultured astrocytes treated with ent-Sauchinone (1, 5, and 10 μM) for 24 hours. For the detection of anti-neuro-inflammatory responses, reative oxygen species (ROS) and Nitric oxide (NO) generation and inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression were measured with assay kits and western blotting. β-secretase and β-secretase activities and β-amyloid levels were determined for measuring the anti-amyloidogenic effects of ent-Sauchinone by enzyme assay kits. NF-κB and STAT3 signals were detected with electromobility shift assay (EMSA) to study the related signaling pathways. The binding of ent-Sauchinone to STAT3 was evaluated by a pull-down assay and by a docking model using Autodock VINA software (Hoover's Inc., Texas, United states).
  
  
  RESULTS
  ent-Sauchinone (1, 5, and 10 μM) effectively decreased lipopolysaccharide (LPS)-(1 μg/ml) induced inflammatory responses through the reduction of ROS and NO generations and iNOS and COX-2 expressions in cultured astrocytes and microglial BV-2 cells. ent-Sauchinone also inhibited LPS-induced amyloidogenesis through the inhibition of β-secretase and β-secretase activity. NF- κB amyloid and STAT3, critical transcriptional factors regulating not only inflammation but also amyloidogenesis, were also inhibited in a concentration dependent manner by ent-Sauchinone by blocking the phosphorylation of I κB and STAT3 in cultured astrocytes and microglial BV-2 cells. The docking model approach showed that ent-Sauchinone binds to STAT3, and the employment of a STAT3 inhibitor and siRNA reversed ent-Sauchinone-induced inhibition NF-κB activation and Aβ generation.
  
  
  CONCLUSIONS
  These results indicated that ent-Sauchinone inhibited neuroinflammation and amyloidogenesis through the inhibition of STAT3-mediated NF-κB activity, and thus could be applied in the treatment of neuro-inflammatory diseases, including Alzheimer's disease.
authors.affiliation: College of Pharmacy and MRC, Chungbuk National University, 52 Naesudong-ro, Heungduk-gu, Cheongju, Chungbuk 361-763, Republic of Korea. fgkmn@hanmail.net.
authors.forename: Suk-Young
authors.initials: SY
authors.lastname: Song
authors.forename: Yu Yeon
authors.initials: YY
authors.lastname: Jung
authors.forename: Chul Ju
authors.initials: CJ
authors.lastname: Hwang
authors.forename: Hee Peom
authors.initials: HP
authors.lastname: Lee
authors.forename: Chang Hyun
authors.initials: CH
authors.lastname: Sok
authors.forename: Joo Hwan
authors.initials: JH
authors.lastname: Kim
authors.forename: Sang Min
authors.initials: SM
authors.lastname: Lee
authors.forename: Hyun Ok
authors.initials: HO
authors.lastname: Seo
authors.forename: Byung Kook
authors.initials: BK
authors.lastname: Hyun
authors.forename: Dong Young
authors.initials: DY
authors.lastname: Choi
authors.forename: Sang Bae
authors.initials: SB
authors.lastname: Han
authors.forename: Young Wan
authors.initials: YW
authors.lastname: Ham
authors.forename: Bang Yeon
authors.initials: BY
authors.lastname: Hwang
authors.forename: Jin Tae
authors.initials: JT
authors.lastname: Hong
mesh_terms: D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects*; D001578:Benzopyrans / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D051546:Cyclooxygenase 2 / Q000378:metabolism; D004149:Dioxoles / Q000494:pharmacology*; D024202:Electrophoretic Mobility Shift Assay; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D017628:Microglia / Q000187:drug effects; D016328:NF-kappa B / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D016229:Amyloid beta-Peptides; D001578:Benzopyrans; D004149:Dioxoles; D005904:Glial Fibrillary Acidic Protein; D008070:Lipopolysaccharides; D016328:NF-kappa B; D010446:Peptide Fragments; D017382:Reactive Oxygen Species; D050796:STAT3 Transcription Factor; C494088:Stat3 protein, rat; C075222:amyloid beta-protein (1-42); C410958:sauchinone; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D051546:Cyclooxygenase 2