Sequence-Specific Recognition of Double-Stranded DNA by Peptide Nucleic Acid Forming Double-Duplex Invasion Complex

Peptide nucleic acid (PNA) is an analog of natural nucleic acids, where the sugar-phosphate backbone of DNA is replaced by an electrostatically neutral N-(2-aminoethyl)glycine backbone. This unique peptide-based backbone enables PNAs to form a very stable duplex with the complementary nucleic acids via Watson–Crick base pairing since there is no electrostatic repulsion between PNA and DNA·RNA. With this high nucleic acid affinity, PNAs have been used in a wide range of fields, from biological applications such as gene targeting, to engineering applications such as probe and sensor developments. In addition to single-stranded DNA, PNA can also recognize double-stranded DNA (dsDNA) through the formation of a double-duplex invasion complex. This double-duplex invasion is hard to achieve with other artificial nucleic acids and is expected to be a promising method to recognize dsDNA in cellula or in vivo since the invasion does not require the prior denaturation of dsDNA. In this paper, we provide basic knowledge of PNA and mainly focus on the research of PNA invasion

Investigation of the Characteristics of NLS-PNA: Influence of NLS Location on Invasion Efficiency

Peptide nucleic acid can recognise sequences in double-stranded DNA (dsDNA) through the formation of a double-duplex invasion complex. This double-duplex invasion is a promising method for the recognition of dsDNA in cellula because peptide nucleic acid (PNA) invasion does not require the prior denaturation of dsDNA. To increase its applicability, we developed PNAs modified with a nuclear localisation signal (NLS) peptide. In this study, the characteristics of NLS-modified PNAs were investigated for the future design of novel peptide-modified PNAs

Sequence-Specific Recognition of Double-Stranded DNA by Using Only PNAs in Parallel with Natural Nucleobases

The sequence-specific recognition of double-stranded DNA (dsDNA) is a key property for the control of DNA function. Peptide nucleic acid (PNA) can be utilised for the direct recognition of dsDNA via the formation of a unique invasion complex. Strand invasion by PNA induces local changes in the structure of dsDNA and is useful for the regulation of gene expression and genome editing. However, the fact that nucleobases modification is required for efficient invasion, has stymied the wide-spread application of PNA. Herein, we succeeded in the efficient recognition of target dsDNA sequences via formation of invasion complex by utilising only parallel-stranded and unmodified PNAs. This approach also streamlines synthesis by permitting the use of a peptide synthesiser rather than the manual synthesis we had been dependent upon for nucleobase-modified PNAs. Our new method also exhibited high sequence specificity and flexibility for target dsDNA sequences

Combination of Serine Protease Inhibitor FUT-175 and Thromboxane Synthetase Inhibitor OKY-046 Decreases Cerebral Vasospasm in Patients with Subarachnoid Hemorrhage

クモ膜下出血後(SAH)の脳血管攣縮発現に補体活性化を介する炎症反応が関与するとの考えらか、抗補体活性化作用を有するserine protease inhibitor(FUT-175)を従来の抗攣縮治療であるTXA2合成阻害薬(OKY-046)とともに使用し、その有効性に関しFisher group 3の高度なクモ膜下出血症例を対象として検討した。その結果FUT-175とOKY-046の併用は、OKY-046単独使用に比べ、Hunt and Hess IIIとIVの症例において有意に血管攣縮発現を抑制し(<0.02)、Hunt and Hess Vを除くoverallの予後を有意に改善した(<0.05)。FUTの使用はSAH発症48時間以内、1日80mg以上が有効であった。The preventive effect of the serine protease inhibitor FUT-175 (nafamostat mesilate), a potent inhibitor of the complement system, against vasospasm was evaluated in 34 high risk patients with thick and diffuse subarachnoid hemorrhage (SAH) demonstrated by computed tomography corresponding to Fisher group 3. All patients underwent surgery within 96 hours following SAH and received the thromboxane A_2 synthetase inhibitor, OKY-046, as part of standard care. FUT-175 (40-160 mg/day) was administered during the initial 4 days following surgery. 455 patients treated without FUT-175 in the Nagasaki SAH Data Bank (non-FUT group) formed the control group. FUT-175 significantly decreased the incidence of symptomatic vasospasm in patients with severe neurological grade (Hunt and Hess grade 3, p<0.02 ; Hunt and Hess grade 4, p<0.02). The incidence of favorable outcome was 76.5% in the FUT group and 60.4% in the non-FUT group, but not statistically different. However, when patients of Hunt and Hess grade 5 were excluded, the FUT group had a significantly improved outcome (p<0.05). This study suggests that FUT-175 has an additive effect to OKY-046 in preventing vasospasm in high risk patients with severe SAH

Preparation of Photocrosslinked Fish Elastin Polypeptide/Microfibrillated Cellulose Composite Gels with Elastic Properties for Biomaterial Applications

Photocrosslinked hydrogels reinforced by microfibrillated cellulose (MFC) were prepared from a methacrylate-functionalized fish elastin polypeptide and MFC dispersed in dimethylsulfoxide (DMSO). First, a water-soluble elastin peptide with a molecular weight of ca. 500 g/mol from the fish bulbus arteriosus was polymerized by N,N′-dicyclohexylcarbodiimide (DCC), a condensation reagent, and then modified with 2-isocyanatoethyl methacrylate (MOI) to yield a photocrosslinkable fish elastin polypeptide. The product was dissolved in DMSO and irradiated with UV light in the presence of a radical photoinitiator. We obtained hydrogels successfully by substitution of DMSO with water. The composite gel with MFC was prepared by UV irradiation of the photocrosslinkable elastin polypeptide mixed with dispersed MFC in DMSO, followed by substitution of DMSO with water. The tensile test of the composite gels revealed that the addition of MFC improved the tensile properties, and the shape of the stress–strain curve of the composite gel became more similar to the typical shape of an elastic material with an increase of MFC content. The rheology measurement showed that the elastic modulus of the composite gel increased with an increase of MFC content. The cell proliferation test on the composite gel showed no toxicity