Cell Delivery: Routing Nanomolar Protein Cargoes to Lipid Raft-Mediated/Caveolar Endocytosis through a Ganglioside GM1-Specific Recognition Tag (Adv. Sci. 4/2020)

In article number 1902621, Tamás A. Martinek and co-workers develop a pentapeptidic tag, which reads the glycan code of ganglioside GM1 and triggers lipid raft-mediated endocytosis, avoiding lysosomal entrapment. This carrier molecule can deliver macromolecular cargoes (e.g., IgG complexes) into live cells with the possibility to escape to the cytosol.Peer reviewe

Routing Nanomolar Protein Cargoes to Lipid Raft-Mediated/Caveolar Endocytosis through a Ganglioside GM1‐Specific Recognition Tag

There is a pressing need to develop ways to deliver therapeutic macromolecules to their intracellular targets. Certain viral and bacterial proteins are readily internalized in functional form through lipid raft-mediated/caveolar endocytosis, but mimicking this process with protein cargoes at therapeutically relevant concentrations is a great challenge. Targeting ganglioside GM1 in the caveolar pits triggers endocytosis. A pentapeptide sequence WYKYW is presented, which specifically captures the glycan moiety of GM1 (K-D = 24 nm). The WYKYW-tag facilitates the GM1-dependent endocytosis of proteins in which the cargo-loaded caveosomes do not fuse with lysosomes. A structurally intact immunoglobulin G complex (580 kDa) is successfully delivered into live HeLa cells at extracellular concentrations ranging from 20 to 160 nm, and escape of the cargo proteins to the cytosol is observed. The short peptidic WYKYW-tag is an advantageous endocytosis routing sequence for lipid raft-mediated/caveolar cell delivery of therapeutic macromolecules, especially for cancer cells that overexpress GM1.Peer reviewe

α/β-Peptides as Nanomolar Triggers of Lipid Raft-Mediated Endocytosis through GM1 Ganglioside Recognition

Cell delivery of therapeutic macromolecules and nanoparticles is a critical drug development challenge. Translocation through lipid raft-mediated endocytic mechanisms is being sought, as it can avoid rapid lysosomal degradation. Here, we present a set of short α/β-peptide tags with high affinity to the lipid raft-associated ganglioside GM1. These sequences induce effective internalization of the attached immunoglobulin cargo. The structural requirements of the GM1-peptide interaction are presented, and the importance of the membrane components are shown. The results contribute to the development of a receptor-based cell delivery platform

Rationally Designed Foldameric Adjuvants Enhance Antibiotic Efficacy via Promoting Membrane Hyperpolarization

The negative membrane potential of bacterial cells influences crucial cellular processes. Inspired by the molecular scaffold of the antimicrobial peptide PGLa, we have developed antimicrobial foldamers with a computer-guided design strategy. The novel PGLa analogues induce sustained membrane hyperpolarization. When co-administered as an adjuvant, the resulting compounds – PGLb1 and PGLb2 – have substantially reduced the level of antibiotic resistance of multi-drug resistant Escherichia coli, Klebsiella pneumoniae and Shigella flexneri clinical isolates. The observed antibiotic potentiation was mediated by hyperpolarization of the bacterial membrane caused by the alteration of cellular ion transport. Specifically, PGLb1 and PGLb2 are selective ionophores that enhance the Goldman–Hodgkin–Katz potential across the bacterial membrane. These findings indicate that manipulating bacterial membrane electrophysiology could be a valuable tool to overcome antimicrobial resistance