Design of a Pep-1 peptide-modified liposomal nanocarrier system for intracellular drug delivery: Conformational characterization and cellular uptake evaluation.

In order to facilitate the intracellular delivery of macromolecules, Pep-1 peptide-modified liposomal (Pep1-Lipo) nanocarriers were designed and examined for their in vitro cell translocation capability. Pep-1 peptides were coupled via thiol-maleimide linkage to small unilamellar vesicles composed of phosphatidylcholine, Tween 80, and N-[4-(p-maleimidophenyl)butyryl]-phosphatidylethanolamine (MPB-PE). The amount of Pep-1 peptide conjugated to the vesicle was effectively controlled by the amounts of maleimide groups on the vesicular surface, ranging from 70 to 700 molecules per vesicle. Systems were evaluated for cell uptake capacity by monitoring entrapped fluorescence-labeled bevacizumab, a model protein for poorly permeable macromolecule, using confocal microscopy. The novel carriers rapidly bound to the cell membrane and migrated into the cells within 1 h, exhibiting better translocation of macromolecules compared to that of conventional liposomes. Cellular uptake of Pep1-Lipo was proportional to the amount of Pep-1 peptide on the liposomal surface. In conclusion, we found that the Pep1-Lipo formulation was a promising nanocarrier system for intracellular delivery of macromolecules.

Transduced human PEP-1-heat shock protein 27 efficiently protects against brain ischemic insult.

Reactive oxygen species contribute to the development of various human diseases. Ischemia is characterized by both significant oxidative stress and characteristic changes in the antioxidant defense mechanism. Heat shock protein 27 (HSP27) has a potent ability to increase cell survival in response to oxidative stress. In the present study, we have investigated the protective effects of PEP-1-HSP27 against cell death and ischemic insults. When PEP-1-HSP27 fusion protein was added to the culture medium of astrocyte and primary neuronal cells, it rapidly entered the cells and protected them against cell death induced by oxidative stress. Immunohistochemical analysis revealed that, when PEP-1-HSP27 fusion protein was intraperitoneally injected into gerbils, it prevented neuronal cell death in the CA1 region of the hippocampus in response to transient forebrain ischemia. Our results demonstrate that transduced PEP-1-HSP27 protects against cell death in vitro and in vivo, and suggest that transduction of PEP-1-HSP27 fusion protein provides a potential strategy for therapeutic delivery in various human diseases in which reactive oxygen species are implicated, including stroke.