The application of strand invasion phenomenon, directed by peptide nucleic acid (PNA) and single-stranded DNA binding protein (SSB) for the recognition of specific sequences of human endogenous retroviral HERV-W family.

The HERV-W family of human endogenous retroviruses represents a group of numerous sequences that show close similarity in genetic composition. It has been documented that some members of HERV-W-derived expression products are supposed to play significant role in humans' pathology, such as multiple sclerosis or schizophrenia. Other members of the family are necessary to orchestrate physiological processes (eg, ERVWE1 coding syncytin-1 that is engaged in syncytiotrophoblast formation). Therefore, an assay that would allow the recognition of particular form of HERV-W members is highly desirable. A peptide nucleic acid (PNA)-mediated technique for the discrimination between multiple sclerosis-associated retrovirus and ERVWE1 sequence has been developed. The assay uses a PNA probe that, being fully complementary to the ERVWE1 but not to multiple sclerosis-associated retrovirus (MSRV) template, shows high selective potential. Single-stranded DNA binding protein facilitates the PNA-mediated, sequence-specific formation of strand invasion complex and, consequently, local DNA unwinding. The target DNA may be then excluded from further analysis in any downstream process such as single-stranded DNA-specific exonuclease action. Finally, the reaction conditions have been optimized, and several PNA probes that are targeted toward distinct loci along whole HERV-W env sequences have been evaluated. We believe that PNA/single-stranded DNA binding protein-based application has the potential to selectively discriminate particular HERV-W molecules as they are at least suspected to play pathogenic role in a broad range of medical conditions, from psycho-neurologic disorders (multiple sclerosis and schizophrenia) and cancers (breast cancer) to that of an auto-immunologic background (psoriasis and lupus erythematosus).

'Click' chemistry synthesis and capillary electrophoresis study of 1,4-linked 1,2,3-triazole AZT-systemin conjugate.

The Cu(I) catalyzed Huisgen 1,3-dipolar azide-alkyne cycloaddition (CuAAC) was applied for a nucleoside-peptide bioconjugation. Systemin (Sys), an 18-aa plant signaling peptide naturally produced in response to wounding or pathogen attack, was chemically synthesized as its N-propynoic acid functionalized analog (Prp-Sys) using the SPPS. Next, CuAAC was applied to conjugate Prp-Sys with 3'-azido-2',3'-dideoxythymidine (AZT), a model cargo molecule. 1,4-Linked 1,2,3-triazole AZT-Sys conjugate was designed to characterize the spreading properties and ability to translocate of cargo molecules of systemin. CuAAC allowed the synthesis of the conjugate in a chemoselective and regioselective manner, with high purity and yield. The presence of Cu(I) ions generated in situ drove the CuAAC reaction to completion within a few minutes without any by-products. Under typical separation conditions of phosphate 'buffer' at low pH and uncoated fused bare-silica capillary, an increasing peak intensity assigned to triazole-linked AZT-Sys conjugate was observed using capillary electrophoresis (CE) during CuAAC. CE analysis showed that systemin peptides are stable in tomato leaf extract for up to a few hours. CE-ESI-MS revealed that the native Sys and its conjugate with AZT are translocated through the tomato stem and can be directly detected in stem exudates. The results show potential application of systemin as a transporter of low molecular weight cargo molecules in tomato plant and of CE method to characterize a behavior of plant peptides and its analogs.

Publisher Correction: Transportan 10 improves the pharmacokinetics and pharmacodynamics of vancomycin.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Transportan 10 improves the pharmacokinetics and pharmacodynamics of vancomycin.

In the presented study, transportan 10 (TP10), an amphipathic cell penetrating peptide (CPP) with high translocation activity, was conjugated with vancomycin (Van), which is known for poor access to the intracellular bacteria and the brain. The antibacterial activity of the conjugates was tested on selected clinical strains of methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus sp. It turned out that all of them had superior antimicrobial activity in comparison to that of free Van, which became visible particularly against clinical MRSA strains. Furthermore, one of the conjugates was tested against MRSA - infected human cells. With respect to them, this compound showed high bactericidal activity. Next, the same conjugate was screened for its capacity to cross the blood brain barrier (BBB). Therefore, qualitative and quantitative analyses of the conjugate's presence in the mouse brain slices were carried out after its iv administration. They indicated the conjugate's presence in the brain in amount >200 times bigger than that of Van. The conjugates were safe with respect to erythrocyte toxicity (erythrocyte lysis assay). Van in the form of a conjugate with TP10 acquires superior pharmacodynamic and pharmacokinetic.

A Novel, Highly Selective RT-QPCR Method for Quantification of MSRV Using PNA Clamping Syncytin-1 (ERVWE1).

HERV-W is a multi-locus family of human endogenous retroviruses (HERVs) that has been found to play an important role in human physiology and pathology. Two particular members of HERV-W family are of special interests: ERVWE1 (coding syncytin-1, which is a glycoprotein essential in the formation of the placenta) and MSRV (multiple sclerosis-associated retrovirus that is thought to play a significant role in human pathology as a result of its increased expression in the brain tissue and blood cells derived from patients with multiple sclerosis (MS)). Both ERVWE1 and MSRV mRNA share high level of similarity and hence a method that allows to exclusively quantify the MSRV expression in clinical samples would be desirable. We developed a quantitative polymerase chain reaction (QPCR) technique for the detection and quantification of the multiple sclerosis-associated retrovirus. The assay utilises fluorescently labelled oligonucleotide probe, which is complementary to the conservative fragment of MSRV env gene and a peptide nucleic acid (PNA) probe, fully complementary to the ERVWE1 sequence fragment that efficiently blocks the polymerase action on ERVWE1 templates. The PNA molecule, if used parallel with hydrolysis probe in QPCR analysis, greatly facilitates the detection efficiency of MSRV even if ERVWE1 is present abundantly in respect to MSRV in the analysed sample. We achieved a wide and measurable range from 1 × 10 e(2) to 1 × 10 e(8) copies/reaction; the linearity of the technique was maintained even at the low MSRV level of 1% in respect to ERVWE1. Using our newly developed method we confirmed that the expression of MSRV takes place in normal human astrocytes and in human umbilical vein endothelial cells in vitro. We also found that the stimulation of human monocytes did not influence the specific expression of MSRV but it caused changes in mRNA level of distinct HERV-W templates.

Synthesis and hybridization studies of a new CPP-PNA conjugate as a potential therapeutic agent in atherosclerosis treatment.

The objective of this study was to design and synthesize a new CPP-PNA conjugate that would be able to penetrate endothelial cells, bind STAT1 mRNA and thereby block the activity of STAT1 (the Signal Transducer and Activator of Transcription 1), which is important in cases of vessel inflammation. In the course of the study, the TAMRA-PTD-4- Hal(traziole-Gly-PNA)-conjugate was successfully synthesized using a specific 1,3-dipolar Huisgen cycloaddition reaction known as a "click reaction". The hybridization properties of the conjugate to complementary hSTAT1 mRNA and hSTAT1 ssDNA fragments was verified by capillary electrophoresis (CE). Studies have shown that the attachment of a fluorescence-labeled peptide to a PNA sequence via a 1,2,3-triazole ring did not alter the binding properties of the PNA to the complementary hSTAT1 mRNA or hSTAT1 ssDNA fragments maintaining similar binding affinity. Furthermore, the data obtained suggest that the use of such a conjugate to modulate the activity and expression of STAT1 could provide a new therapeutic strategy for atherosclerosis treatment.

Protein and siRNA delivery by transportan and transportan 10 into colorectal cancer cell lines.

INTRODUCTION: Cell penetrating peptides (CPPs) have the ability to translocate through cell membranes with high efficiency and therefore can introduce biological agents with pharmaceutical properties into the cell. Transportan (TP) and its shorter analog transportan 10 (TP10) are among the best studied CPPs, however, their effects on viability of and cargo introduction into colorectal cancer (CRC) cells have yet not been investigated. The aim of our study was to evaluate the cytotoxic effects of TP and TP10 on representative CRC lines and the efficiency of protein (streptavidin) and siRNA cargo delivery by TP-biotinylated derivatives (TP-biot). MATERIAL AND METHODS: HT29 (early stage CRC model) and HCT116 (metastatic CRC model) cell lines were incubated with TP, TP10, TP-biot1, TP-biot13 and TP10-biot1. The effects of studied CPPs on cell viability and cell cycle were assessed by MTT and annexin V assays. The uptake of streptavidin-FITC complex into cells was determined by flow cytometry and fluorescence microscopy, with the inhibition of cellular vesicle trafficking by brefeldin A. The efficiency of siRNA for SASH1 gene delivery was measured by quantitative PCR (qPCR). RESULTS: Since up to 10 µM concentrations of each CPP showed no significant cytotoxic effect, the concentrations of 0.5-5 µM were used for further analyses. Within this concentration range none of the studied CPPs affected cell viability and cell cycle. The efficient and endocytosis-independent introduction of streptavidin-FITC complex into cells was observed for TP10-biot1 and TP-biot1 with the cytoplasmic location of the fluorescent cargo; decreased SASH1 mRNA level was noticed with the use of siRNA and analyzed CPPs. CONCLUSIONS: We conclude that TP, TP10 and their biotinylated derivatives can be used as efficient delivery vehicles of small and large cargoes into CRC cells.