title: Bioorthogonal probes for imaging sterols in cells.
abstract: Cholesterol is a fundamental lipid component of eukaryotic membranes and a precursor of potent signaling molecules, such as oxysterols and steroid hormones. Cholesterol and oxysterols are also essential for Hedgehog signaling, a pathway critical in embryogenesis and cancer. Despite their importance, the use of imaging sterols in cells is currently very limited. We introduce a robust and versatile method for sterol microscopy based on C19 alkyne cholesterol and oxysterol analogues. These sterol analogues are fully functional; they rescue growth of cholesterol auxotrophic cells and faithfully recapitulate the multiple roles that sterols play in Hedgehog signal transduction. Alkyne sterol analogues incorporate efficiently into cellular membranes and can be imaged with high resolution after copper(I)-catalyzed azide-alkyne cycloaddition reaction with fluorescent azides. We demonstrate the use of alkyne sterol probes for visualizing the subcellular distribution of cholesterol and for two-color imaging of sterols and choline phospholipids. Our imaging strategy should be broadly applicable to studying the role of sterols in normal physiology and disease.
authors: Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115 (USA).
authors: Cindy Y
authors: CY
authors: Jao
authors: Daniel
authors: D
authors: Nedelcu
authors: Lyle V
authors: LV
authors: Lopez
authors: Thilani N
authors: TN
authors: Samarakoon
authors: Ruth
authors: R
authors: Welti
authors: Adrian
authors: A
authors: Salic
mesh_terms: D000480:Alkynes / Q000737:chemistry; D000818:Animals; D001386:Azides / Q000737:chemistry; D002784:Cholesterol / Q000031:analogs & derivatives; D057930:Click Chemistry; D003300:Copper / Q000737:chemistry; D061565:Cycloaddition Reaction; D053823:Hedgehog Proteins / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008853:Microscopy / Q000379:methods; D015335:Molecular Probes / Q000737:chemistry; D041681:NIH 3T3 Cells; D061848:Optical Imaging / Q000379:methods; D015398:Signal Transduction; D013261:Sterols / Q000032:analysis* / Q000378:metabolism
chemical_list: D000480:Alkynes; D001386:Azides; D053823:Hedgehog Proteins; D015335:Molecular Probes; D013261:Sterols; D003300:Copper; D002784:Cholesterol
keywords: Hedgehog signaling; cholesterol; click chemistry; membranes; microscopy