Early Endosomal Escape of a Cyclic Cell-Penetrating Peptide Allows Effective Cytosolic Cargo Delivery

详细信息    查看全文

• 作者：Ziqing Qian ; Jonathan R. LaRochelle ; Bisheng Jiang ; Wenlong Lian ; Ryan L. Hard ; Nicholas G. Selner ; Rinrada Luechapanichkul ; Amy M. Barrios ; Dehua Pei
• 刊名：Biochemistry
• 出版年：2014
• 出版时间：June 24, 2014
• 年：2014
• 卷：53
• 期：24
• 页码：4034-4046
• 全文大小：584K
• ISSN：1520-4995

文摘

Cyclic heptapeptide cyclo(F桅RRRRQ) (cF桅R₄, where 桅 is l-2-naphthylalanine) was recently found to be efficiently internalized by mammalian cells. In this study, its mechanism of internalization was investigated by perturbing various endocytic events through the introduction of pharmacologic agents and genetic mutations. The results show that cF桅R₄ binds directly to membrane phospholipids, is internalized into human cancer cells through endocytosis, and escapes from early endosomes into the cytoplasm. Its cargo capacity was examined with a wide variety of molecules, including small-molecule dyes, linear and cyclic peptides of various charged states, and proteins. Depending on the nature of the cargos, they may be delivered by endocyclic (insertion of cargo into the cF桅R₄ ring), exocyclic (attachment of cargo to the Gln side chain), or bicyclic approaches (fusion of cF桅R₄ and cyclic cargo rings). The overall delivery efficiency (i.e., delivery of cargo into the cytoplasm and nucleus) of cF桅R₄ was 4鈥?2-fold higher than those of nonaarginine, HIV Tat-derived peptide, or penetratin. The higher delivery efficiency, coupled with superior serum stability, minimal toxicity, and synthetic accessibility, renders cF桅R₄ a useful transporter for intracellular cargo delivery and a suitable system for investigating the mechanism of endosomal escape.