A novel intrinsically fluorescent probe for study of uptake and trafficking of 25-hydroxycholesterol.
Cholesterol homeostasis is regulated not only by cholesterol, but also by oxygenated cholesterol species, referred to as oxysterols. Side-chain oxysterols, such as 25-hydroxycholesterol (25-HC), regulate cholesterol homeostasis through feedback inhibition and feed-forward activation of transcriptional pathways that govern cholesterol synthesis, uptake, and elimination, as well as through direct nongenomic actions that modulate cholesterol accessibility in membranes. Elucidating the cellular distribution of 25-HC is required to understand its biological activity at the molecular level. However, studying oxysterol distribution and behavior within cells has proven difficult due to the lack of fluorescent analogs of 25-HC that retain its chemical and physical properties. To address this, we synthesized a novel intrinsically fluorescent 25-HC mimetic, 25-hydroxycholestatrienol (25-HCTL). We show that 25-HCTL modulates sterol homeostatic responses in a similar manner as 25-HC. 25-HCTL associates with lipoproteins in media and is taken up by cells through LDL-mediated endocytosis. In cultured cells, 25-HCTL redistributes among cellular membranes and, at steady state, has a similar distribution as cholesterol, being enriched in both the endocytic recycling compartment as well as the plasma membrane. Our findings indicate that 25-HCTL is a faithful fluorescent 25-HC mimetic that can be used to investigate the mechanisms through which 25-HC regulates sterol homeostatic pathways.
Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065.
David B
DB
Iaea
Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St. Louis, MO 63110.
Sarah E
SE
Gale
Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St. Louis, MO 63110.
Agata A
AA
Bielska
Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110.
Kathiresan
K
Krishnan
Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St. Louis, MO 63110.
Hideji
H
Fujiwara
Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St. Louis, MO 63110.
Hui
H
Jiang
Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065.
Frederick R
FR
Maxfield
Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110.
Paul H
PH
Schlesinger
Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110.
Douglas F
DF
Covey
Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St. Louis, MO 63110.
Jean E
JE
Schaffer
Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St. Louis, MO 63110 dory@wustl.edu.
Daniel S
DS
Ory
D000818:Animals; D016466:CHO Cells; D002784:Cholesterol / Q000032:analysis; D003412:Cricetulus; D005456:Fluorescent Dyes; D006801:Humans; D006888:Hydroxycholesterols / Q000032:analysis*; D050356:Lipid Metabolism
D005456:Fluorescent Dyes; D006888:Hydroxycholesterols; C007997:25-hydroxycholesterol; D002784:Cholesterol
cholestatrienol; cholesterol; cholesterol homeostasis; lipoprotein; oxysterol