Biotinylated cationic amphiphilic polyproline helices: A noncovalent delivery strategy
Abstract
Efficient delivery of therapeutic biopolymers across cell membranes remains a daunting challenge. The development of cell penetrating peptides (CPPs) has been useful, however, many CPPS are found trapped within endosomes, thereby limiting their use as delivery agents. Covalent attachment of cargo to CPPs may also interfere with the mode of action of the therapy being delivered. A class of CPPs, cationic amphiphilic polyproline helices (CAPHs), have been optimized for non-covalent delivery of cargo and for direct transport into cells with mitochondrial localization. The CAPHs have been modified via biotinylation in order to take advantage of the four binding sites of streptavidin as a means to non-covalently deliver cargo across the cell membrane. The uptake of biotin-modified P14LRR and streptavidin has been found to efficiently bring streptavidin into cells with high efficiency and low toxicity. The additional binding sites on streptavidin have been taken advantage of to bring in a biotinylated fluorophore. This biotin-CAPH/streptavidin system shows promise for deliver of biotinylated therapeutics. Previous research with the CAPH P11LRR has demonstrated cell entry by two distinct pathways: an endocytotic pathway was favored at concentrations below 10 μM, whereas internalization by direct transport was observed at concentrations greater that 25 μM. The CAPH was elongated to P14LRR to introduce additional cationic and hydrophobic groups within the helix to increase interaction with the membrane thereby improving cellular uptake. Uptake of P14LRR was found to be superior compared to P11LRR and Tatp. Subcellular localization of P14LRR followed the same trend as P11LRR with an endocytotic mechanism of entry at concentrations below 1 μM and a direct transport pathway at concentrations greater than 5 μM.
Degree
M.S.
Advisors
Chmielewski, Purdue University.
Subject Area
Chemistry|Biochemistry
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