Augmented osteogenesis of mesenchymal stem cells using a fragmented Runx2 mixed with cell-penetrating, dimeric a-helical peptide.

The intracellular delivery of transcription factor/cofactor using cell penetrating peptide (CPP) can lead to selective osteogenesis. The present work investigates the cell-penetrating potential of the a cyclic, α-helical cell-penetrating peptide based on leucine and lysine residues (cLK) for intracellular delivery in MC3T3 cells and the osteogenic effects of a C-terminal proline‑serine‑threonine-rich (PST) domain of Runx2 using cLK in rat mesenchymal stem cells (MSCs). We confirmed that the combination of cLK and fluorescein 5-isothiocyanate (FITC)-fragmented-Runx2 (fRunx2) showed an enhanced cell-penetrating activity of FITC-fRunx2 compared with FITC-fRunx2 alone.

Multimeric Amphipathic α-Helical Sequences for Rapid and Efficient Intracellular Protein Transport at Nanomolar Concentrations.

An amphipathic leucine (L) and lysine (K)-rich α-helical peptide is multimerized based on helix-loop-helix structures to maximize the penetrating activities. The multimeric LK-based cell penetrating peptides (LK-CPPs) can penetrate cells as protein-fused forms at 100-1000-fold lower concentrations than Tat peptide. The enhanced penetrating activity is increased through multimerization by degrees up to the tetramer level.

Apoptosis inducing, conformationally constrained, dimeric peptide analogs of KLA with submicromolar cell penetrating abilities.

The apoptosis inducing KLA peptide, (KLAKLAK)2, possesses an ability to disrupt mitochondrial membranes. However, this peptide has a poor eukaryotic cell penetrating potential and, as a result, it requires the assistance of other cell penetrating peptides for effective translocation in micromolar concentrations. In an effort to improve the cell penetrating potential of KLA, we have created a library in which pairs of residues on its hydrophobic face are replaced by Cys.

Cell-penetrating, dimeric α-helical peptides: nanomolar inhibitors of HIV-1 transcription.

We constructed dimeric α-helical peptide bundles based on leucine (L) and lysine (K) residues for both efficient cell penetration and inhibition of the Tat-TAR interaction. The LK dimers can penetrate nearly quantitatively into eukaryotic cells and effectively inhibit the elongation of the TAR transcript at low nanomolar concentrations. The effective inhibition of HIV-1 replication strongly suggests that the LK dimer has strong potential as an anti-HIV-1 drug.

Circulatory osmotic desalination driven by a mild temperature gradient based on lower critical solution temperature (LCST) phase transition materials.

Abrupt changes in effective concentration and osmotic pressure of lower critical solution temperature (LCST) mixtures facilitate the design of a continuous desalination method driven by a mild temperature gradient. We propose a prototype desalination system by circulating LCST mixtures between low and high temperature (low T and high T) units. Water molecules could be drawn from a high-salt solution to the LCST mixture through a semipermeable membrane at a temperature lower than the phase transition temperature, at which the effective osmotic pressure of the LCST mixture is higher than the high-salt solution.

Preparation of non-aggregated fluorescent nanodiamonds (FNDs) by non-covalent coating with a block copolymer and proteins for enhancement of intracellular uptake.

Fluorescent nanodiamonds (FNDs) are very promising fluorophores for use in biosystems due to their high biocompatibility and photostability. To overcome their tendency to aggregate in physiological solutions, which severely limits the biological applications of FNDs, we developed a new non-covalent coating method using a block copolymer, PEG-b-P(DMAEMA-co-BMA), or proteins such as BSA and HSA. By simple mixing of the block copolymer with FNDs, the cationic DMAEMA and hydrophobic BMA moieties can strongly interact with the anionic and hydrophobic moieties on the FND surface, while the PEG block can form a shell to prevent the direct contact between FNDs.

Changes in the catalytic properties of Pyrococcus furiosus thermostable amylase by mutagenesis of the substrate binding sites.

Pyrococcus furiosus thermostable amylase (TA) is a cyclodextrin (CD)-degrading enzyme with a high preference for CDs over maltooligosaccharides. In this study, we investigated the roles of four residues (His414, Gly415, Met439, and Asp440) in the function of P. furiosus TA by using site-directed mutagenesis and kinetic analysis.