dcg-04 and 4-4-difluoro-4-bora-3a-4a-diaza-s-indacene

The ubiquitously expressed mannose-6-phosphate receptors (MPRs) are a promising class of receptors for targeted compound delivery into the endolysosomal compartments of a variety of cell types. The development of a synthetic, multivalent, mannose-6-phosphate (M6P) glycopeptide-based MPR ligand is described. The conjugation of this ligand to fluorescent DCG-04, an activity-based probe for cysteine cathepsins, enabled fluorescent readout of its receptor-targeting properties. The resulting M6P-cluster-BODIPY-DCG-04 probe was shown to efficiently label cathepsins in cell lysates as well as in live cells. Furthermore, the introduction of the 6-O-phosphates leads to a completely altered uptake profile in COS and dendritic cells compared to a mannose-containing ligand. Competition with mannose-6-phosphate abolished all uptake of the probe in COS cells, and we conclude that the mannose-6-phosphate cluster targets the MPR and ensures the targeted delivery of cargo bound to the cluster into the endolysosomal pathway.

Topics: Animals; Boron Compounds; Cathepsins; Chlorocebus aethiops; COS Cells; Dendritic Cells; Endosomes; Fluorescent Dyes; Glycopeptides; Leucine; Ligands; Mannosephosphates; Mice; Protein Binding; Receptor, IGF Type 2

Bifunctional, pH-activatable BODIPY dyes were developed and incorporated in mannose cluster-containing activity-based probes for cysteine proteases. Mannose receptor-dependent uptake of the probes in dendritic cells, followed by trafficking to acidic cellular compartments resulted in fluorescence as seen by live-cell imaging, and subsequent cathepsin inhibition.

Topics: Animals; Boron Compounds; Cathepsins; Dendritic Cells; Fluorescent Dyes; Hydrogen-Ion Concentration; Leucine; Mannose; Mice; Microscopy, Fluorescence