Information about cholesterol subcellular localization and transport pathways inside cells is essential for understanding and treatment of cholesterol-related diseases. However, there is a lack of reliable tools to monitor it. This work follows the fate of Sterolight, a BODIPY-labelled sterol, within the cell and demonstrates it as a suitable probe for visualization of sterol/lipid trafficking. Sterolight enters cells through an energy-independent process and knockdown experiments suggest caveolin-1 as its potential cellular carrier. Intracellular transport of Sterolight is a rapid process, and transfer from ER and mitochondria to lysosomes and later to lipid droplets requires the participation of active microtubules, as it can be inhibited by the microtubule disruptor nocodazole. Excess of the probe is actively exported from cells, in addition to being stored in lipid droplets, to re-establish the sterol balance. Efflux occurs through a mechanism requiring energy and may be selectively poisoned with verapamil or blocked in cells with mutated cholesterol transporter NPC1. Sterolight is efficiently transferred within and between different cell populations, making it suitable for monitoring numerous aspects of sterol biology, including the live tracking and visualization of intracellular and intercellular transport.
Alkylation of per-6-azido-β-cyclodextrin by a suitable electrophilic reagent (cinnamyl bromide or propargyl bromide) gave a mixture of 3(I)-O and 2(I)-O regioisomers. After peracetylation and chromatographic separation on silica gel, pure isomers were isolated. Oxidative cleavage of cinnamyl double bond afforded the corresponding formylmethyl and carboxymethyl derivatives. The prepared scaffold molecules are equipped with two types of reactive groups which have a potential to serve as points of attachment for various compounds.
