L17ER4: A cell-permeable attenuated cationic amphiphilic lytic peptide

Kenta Shinga, Takahiro Iwata, Kazuya Murata, Yoko Daitoku, Junya Michibata, Jan Vincent V. Arafiles, Kentarou Sakamoto, Misao Akishiba, Tomoka Takatani-Nakase, Seiya Mizuno, Fumihiro Sugiyama, Miki Imanishi, Shiroh Futaki

Research output: Contribution to journalArticlepeer-review


We have developed a series of attenuated cationic amphiphilic lytic (ACAL) peptides that can efficiently bring immunoglobulin G (IgG) and other functional proteins into cells. Delivery is generally achieved through the coadministration of ACAL peptides with cargo proteins. However, conjugation of ACAL peptides with cargos may be a promising approach for in vivo application to link in vivo outcomes of ACAL peptides and cargos. This study describes the creation of a new cell-permeable ACAL peptide, L17ER4. L17E is an optimized prototype of ACAL peptides previously developed in our laboratory for efficient delivery of IgGs into cells. Delivery was improved by functionalizing L17E with a tetra-arginine (R4) tag. Compared to the use of R8, a representative cell-penetrating peptide with high intracellular delivery efficacy, conjugation with L17ER4 afforded approximately four-fold higher cellular uptake of model small-molecule cargos (fluorescein isothiocyanate and HiBiT peptide). L17ER4 was also able to deliver proteins to cells. Fused with L17ER4, Cre recombinase was delivered into cells. Intracerebroventricular injection of Cre-L17ER4 into green red reporter mice, R26GRR, led to significant in vivo gene recombination in ependymal cells, suggesting that L17ER4 may be used as a cell-penetrating peptide for delivering protein therapeutics into cells in vivo.

Original languageEnglish
Article number116728
JournalBioorganic and Medicinal Chemistry
Publication statusPublished - May 1 2022
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Pharmaceutical Science
  • Drug Discovery
  • Clinical Biochemistry
  • Organic Chemistry


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