title: RNA interference-mediated silencing of BACE and APP attenuates the isoflurane-induced caspase activation.
abstract: BACKGROUND
  β-Amyloid protein (Aβ) has been shown to potentiate the caspase-3 activation induced by the commonly used inhalation anesthetic isoflurane. However, it is unknown whether reduction in Aβ levels can attenuate the isoflurane-induced caspase-3 activation. We therefore set out to determine the effects of RNA interference-mediated silencing of amyloid precursor protein (APP) and β-site APP-cleaving enzyme (BACE) on the levels of Aβ and the isoflurane-induced caspase-3 activation.
  
  
  METHODS
  H4 human neuroglioma cells stably transfected to express full-length human APP (H4-APP cells) were treated with small interference RNAs (siRNAs) targeted at silencing BACE and APP for 48 hours. The cells were then treated with 2% isoflurane for six hours. The levels of BACE, APP, and caspase-3 were determined using Western blot analysis. Sandwich Enzyme-linked immunosorbent assay (ELISA) was used to determine the extracellular Aβ levels in the conditioned cell culture media.
  
  
  RESULTS
  Here we show for the first time that treatment with BACE and APP siRNAs can decrease levels of BACE, full-length APP, and APP c-terminal fragments. Moreover, the treatment attenuates the Aβ levels and the isoflurane-induced caspase-3 activation. These results further suggest a potential role of Aβ in the isoflurane-induced caspase-3 activation such that the reduction in Aβ levels attenuates the isoflurane-induced caspase-3 activation.
  
  
  CONCLUSIONS
  These findings will lead to more studies which aim at illustrating the underlying mechanism by which isoflurane and other anesthetics may affect Alzheimer's disease neuropathogenesis.
authors.affiliation: Geriatric Anesthesia Research Unit, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129-2060; USA. zxie@partners.org.
authors.forename: Yuanlin
authors.initials: Y
authors.lastname: Dong
authors.forename: Zhipeng
authors.initials: Z
authors.lastname: Xu
authors.forename: Yiying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Sayre
authors.initials: S
authors.lastname: McAuliffe
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Xia
authors.initials: X
authors.lastname: Shen
authors.forename: Yun
authors.initials: Y
authors.lastname: Yue
authors.forename: Zhongcong
authors.initials: Z
authors.lastname: Xie