MASUDA, Ryo

ISSN：0918-6158

Outline：Cell-penetrating peptides (CPPs) are attractive tools for delivering macromolecules that have poor membrane permeability, such as antibodies, into cells. However, the major drawback of conventional CPPs is their instability in bodily fluids. We previously reported a novel CPP employing a collagen-like triple-helical structure that exhibited remarkable resistance against serum proteases. Herein, we report the delivery of full-length immunoglobulin G (IgG) antibody into cells using a triple-helical CPP. The CPP was conjugated to IgG via a one-pot reaction using 2-iminothiolane as a crosslinking reagent. The triple-helical CPP was less prone to being aggregated and neutralized by serum than was octaarginine, a conventional CPP. However, most of the conjugates were found to be entrapped in endosomes.

ISSN：17470277

Outline：© 2014 John Wiley & Sons A/S. Using an in vitro random screening of small-molecule compounds, we discovered cis-diamminedichloroplatinum(II) (cisplatin), an anticancer agent, as a potential inhibitor of collagen fibril-formation. The inhibitory effect was found only when cisplatin was dissolved in dimethylsulphoxide (DMSO), indicating that the active species were cisplatin derivatives formed in the DMSO solution. The cisplatin derivatives inhibited the formation of collagen fibrils in vitro without affecting the triple-helical conformation of the collagen molecules. Incubation with the cisplatin solution in DMSO also inhibited in situ deposition of collagen fibrils in a human umbilical vein endothelial cell (HUVEC) culture. In addition, the derivatization of cisplatin in DMSO abolished the cytotoxicity of the original compound. The platinum complex was further revealed to interact with specific sites on the collagen triple helix, and the binding sites were suggested to contain His and/or Met residues. Mass spectrometry analysis of the cisplatin solution in DMSO and a structure-activity relationship study strongly suggested that the active compound is [Pt(NH3)2(Cl)(DMSO)]+. This platinum complex will be useful for investigating molecular mechanisms of collagen self-assembly and for drug development for the treatment of fibrotic diseases. cis-Diamminedichloroplatinum(II) (cisplatin) dissolved in dimethylsulfoxide (DMSO) was discovered as a potential inhibitor of collagen fibril-formation. This platinum complex exhibited inhibitory effects on in vitro collagen fibril-formation and in situ collagen-deposition in a cell culture system, whereas its cytotoxicity was hardly observed. The active species was suggested to be [Pt(NH3)2(Cl)(DMSO)]+, which targeted His and/or Met residues on the collagen triple-helix.

ISSN：17568919

Outline：© 2018 Newlands Press. Aim: The development of a platinum anticancer agent that has improved efficacy by efficient delivery to a tumor and that suppresses side effects has been investigated. Arginine-rich triple-helical peptides are promising drug carriers because of their stability in body fluids and cell-penetrating activity. Results: We synthesized a carboplatin derivative conjugated with an arginine-rich triple-helical peptide. This derivative released platinum under acidic conditions or in the presence Cl - ions. Administration of this derivative to P388 tumor-bearing mice showed comparable survival rates to twice the dose of carboplatin, which was attributed to a longer mean residence time by pharmacokinetics analysis. Conclusion: The collagen-like triple-helical peptide was an efficient carrier of a platinum anticancer agent because of a modification to its pharmacokinetic profile.

ISSN：09186158

Outline：© 2016 The Pharmaceutical Society of Japan.Cell-penetrating peptides (CPPs) are attractive tools for delivering macromolecules that have poor membrane permeability, such as antibodies, into cells. However, the major drawback of conventional CPPs is their instability in bodily fluids. We previously reported a novel CPP employing a collagen-like triple-helical structure that exhibited remarkable resistance against serum proteases. Herein, we report the delivery of full-length immunoglobulin G (IgG) antibody into cells using a triple-helical CPP. The CPP was conjugated to IgG via a one-pot reaction using 2-iminothiolane as a crosslinking reagent. The triple-helical CPP was less prone to being aggregated and neutralized by serum than was octaarginine, a conventional CPP. However, most of the conjugates were found to be entrapped in endosomes.

ISSN：00063525

Outline：© 2016 Wiley Periodicals, Inc.Combinatorial library composed of rigid rod-like peptides with a triple-helical scaffold was constructed. The component peptides were designed to have various combinations of basic and neutral (or hydrophobic) amino acid residues based on collagen-like (Gly-Pro-Yaa)-repeating sequences, inspired from the basic and amphiphilic nature of naturally occurring antimicrobial peptides. Screening of the peptide pools resulted in identification of antimicrobial peptides. A structure-activity relationship study revealed that the position of Arg-cluster at N-terminus and cystine knots at C-terminus in the triple helix significantly contributed to the antimicrobial activity. The most potent peptide RO-A showed activity against Gram-negative Escherichia coli and Gram-positive Bacillus subtilis. In addition, Escherichia coli exposed to RO-A resulted in abnormal elongation of the cells. RO-A was also shown to have remarkable stability in human serum and low cytotoxicity to mammalian cells. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 453–459, 2016.

ISSN：00063525

Outline：© 2016 Wiley Periodicals, Inc.An antimicrobial triple-helical peptide, R3, was previously obtained from a collagen-like combinatorial peptide library. In this research, based on structure–activity relationship studies of R3, a more potent peptide, RR4, with increased positive net charge and charge density relative to R3, was developed. RR4 exhibited antimicrobial activity against both Gram-negative and Gram-positive bacterial strains, including multidrug-resistant strains. Its action could be attributed to entry into cells and interactions with intercellular molecules such as DNA/RNA that inhibited cell division rather than increasing bacterial membrane permeability. Furthermore, RR4 exhibited remarkable stability in serum and low cytotoxicity.