Chlordecone increased subcellular distribution of scavenger receptor class B type II to murine hepatic microsomes without altering cytosolic cholesterol binding proteins

Toxicol Lett. 2009 Dec 1;191(1):20-5. doi: 10.1016/j.toxlet.2009.07.029. Epub 2009 Aug 8.

Abstract

Pretreatment of male C57BL/6 mice with low doses of the persistent organochlorine pesticide, chlordecone (CD), stimulated biliary excretion of exogenous cholesterol (CH) up to 3-fold. Increased biliary excretion occurred without changes in hepatic ATP-binding cassette transporter G8 (ABCG8) of the bile canaliculus or scavenger receptor class B type I (SR-BI) of the sinusoidal surface. A variety of tissues express scavenger receptor class B type II (SR-BII) and this protein was identified as a splice variant from the SR-BI gene. Although the function of SR-BII has not been elucidated it may play a role in CH homeostasis and trafficking distinctly different than SR-BI. Western blotting demonstrated that a single dose of CD promoted subcellular distribution of SR-BII to murine hepatic microsomes about 2.2-fold when compared to controls without effect on liver crude membrane SR-BII content. This was consistent with increased vesicular CH trafficking. Relative quantification of hepatic cytosolic proteins in a fraction that sequestered [(14)C]CH by mass spectrometry (MS) indicated no role for cytosolic CH binding proteins in CD altered CH homeostasis. Western blotting verified no effect of CD on liver fatty acid-binding protein (L-FABP) in cytosol. MS detected a statistically significant increase in myosin-9, which was also consistent with increased vesicular trafficking.

MeSH terms

  • Animals
  • Bile / metabolism
  • Blotting, Western
  • Carrier Proteins / metabolism*
  • Chlordecone / toxicity*
  • Cytosol / drug effects*
  • Cytosol / metabolism*
  • Electrophoresis, Polyacrylamide Gel
  • Fatty Acid-Binding Proteins / metabolism
  • Homeostasis / drug effects
  • Insecticides / toxicity*
  • Male
  • Mass Spectrometry
  • Mice
  • Mice, Inbred C57BL
  • Microsomes, Liver / drug effects*
  • Microsomes, Liver / metabolism*
  • Pancreatic Elastase
  • Scavenger Receptors, Class B / metabolism*
  • Subcellular Fractions / drug effects*
  • Subcellular Fractions / metabolism*

Substances

  • Carrier Proteins
  • Fatty Acid-Binding Proteins
  • Insecticides
  • Scavenger Receptors, Class B
  • Pancreatic Elastase
  • cholesterol-binding protein
  • Chlordecone