Novel Cell Permeable Peptide Based on Multi Basic Furin-dependent Cleavage Site of Respiratory Syncytial Virus Fusion Protein

Cell permeable peptide (CPP) is able to transport itself or conjugated molecules such as nucleotides, peptides, and proteins into cells. Since short peptide of human immunodeficiency virus-1 Tat has been discovered as CPP, it has been continuously studied for their ability to transport heterologous cargoes into cells. In this study, we have focused on the fusion protein of respiratory syncytial virus (RSV), which has six basic amino acids in multi basic furin-dependent cleavage site (MBFCS) required to be cationic CPP. To develop more efficient CPP, the sequence, which linked two MBFCS, was synthesized (called RS-CPP). To assess cell permeable efficiency of RS-CPP or MBFCS, the peptides was conjugated with fluorescein isothiocyanate, and cell permeable efficiency was measured by fluorescence-activated cell sorting. Cell permeability of RS-CPP or MBFCS was increased in a dose-dependent manner, but RS-CPP showed more efficient cell permeability than MBFCS in MDCK, HeLa, Vero E6, and A549 cells. To evaluate whether RS-CPP can transport its conjugated functional peptide (VIVIT) in CD8+ T cell, it was confirmed that IL-2 and β-galactosidase expression were significantly inhibited through selective block of nuclear factor activated T-cell. To investigate endocytic pathways, Cre-mediated DNA recombination (loxP-STOP-loxP-LacZ reporter system) was investigated with divergent endocytosis inhibitors in TE671 cells, and RS-CPP endocytosis is occurred via binding cell surface glycosaminoglycan and clathrin-mediated endocytosis, or macropinocytosis. These results indicated that RS-CPP could be a novel cationic CPP, and it would help understanding for delivery of biologically functional molecules based on viral basic amino acids.

Development and Application of Cell-penetrating Peptides

Intracellular transduction of hydrophilic macromolecules has been problematic owing to the biochemical restriction imposed by lipid bilayer of the cytoplasmic membrane. Several technologies have been developed to improve the intracellular delivery of the large molecules for therapeutic purpose, including cell penetrating peptide. Cell penetrating peptides or cell permeable peptides (CPPs) were initially discovered based on the potency of certain full-length proteins or proteins to translocate across the plasma membrane. Currently, CPPs are broadly applied for intracellular delivery of biologically functional molecules in vivo and vitro, varying from small molecules, peptides, proteins, liposomes and nucleic acids. With introducing the history and characteristics of CPPs, this review will focus on the intracellular transduction mechanism and application of CPPs.

A Case of Oseltamivir-Resistant Pandemic Influenza (H1N1 2009) in a Patient with Acute Myeloid Leukemia / 감염과화학요법

Oseltamivir is the drug of choice for patients with pandemic influenza (H1N1 2009). However, sporadic cases of oseltamivir resistance have been described worldwide. Up to March 2010, a total of 11 strains (2.2% of tested isolates) of oseltamivir-resistant pandemic influenza (H1N1 2009) have been discovered in South Korea. We report a case of 46-year-old man with acute myeloid leukemia in whom an oseltamivir-resistant pandemic (H1N1) 2009 virus was isolated. Despite high dose oseltamivir therapy for 10 days he had persistent symptoms and showed positive results in repeated real-time RT-PCR for pandemic influenza (H1N1 2009) virus from nasopharyngeal specimen. The patient improved eventually after oseltamivir was replaced by zanamivir inhalation.