Amyloid beta (Aβ) aggregation is generally believed as the crucial and primary cause of Alzheimer's disease (AD). However, current Aβ‐targeted therapeutic strategies show limited disease‐modifying efficacy due to the irreversible damages in the late stage of AD, thus the treatment should be given before the formation of deposition and target primary Aβ species rather than advanced plaques. Herein, inspired by heat shock protein, a self‐assembly nanochaperone based on mixed‐shell polymeric micelle (MSPM) is devised to act as a novel strategy for AD prevention. With unique surface hydrophobic domains, this nanochaperone can selectively capture Aβ peptides, effectively suppress Aβ aggregation, and remarkably reduce Aβ‐mediated cytotoxicity. Moreover, the formed nanochaperone‐Aβ complex after Aβ adsorption can be easily phagocytosed by microglia and thereby facilitates Aβ clearance. As a result, the nanochaperone reduces Aβ burden, attenuates Aβ‐induced inflammation, and eventually rescues the cognitive deficits of APP/PS1 transgenic AD mice. These results indicate that this biomimetic nanochaperone can successfully prevent the onset of AD symptoms and serve as a promising candidate for prophylactic treatment of AD.

A new chemosensor, 2,3,15,16-tetrakis(pyridin-2-yl)-7,8,10,11,20,21,23,24-octahydro[1,4,7,10,13,16]hexaoxacyclooctadecino[2,3-g:11,12-g']diquinoxaline (1), containing 2,3-bis(pyridin-2-yl)quinoxaline and crown ether moieties, has been designed and found to be a ratiometric and selective fluorescent detector of Zn(2+) over a wide range of tested metal ions. The addition of Zn(2+) to the solution of 1 in acetonitrile induced the formation of a 1:2 ligand-metal complex, 1-Zn(2+), which exhibits a remarkable enhanced fluorescent emission centered at 460 nm, with the disappearance of the fluorescent emission of 1 centered at 396 nm due to the mechanism of internal charge transfer. In contrast, the presence of K(+) results in the fluorescence quenching of 1 and 1-Zn(2+) through the photoinduced electron-transfer mechanism. These results demonstrate that 1 can perform as not only an INHIBIT logic gate but also an "off-on-off" molecular switch triggered by Zn(2+) and K(+). The structure of complex 1-Zn(2+) has been characterized by single-crystal X-ray crystallography, mass spectrometry, and (1)H NMR titration experiments. Density functional theory calculation results on 1 and the 1-Zn(2+) complex are well consistent with the experimental results.

We presented herein pH-mediated drug release behaviors from a generally recognized “pH-insensitive” star-shaped PCL-POEGMA micelles, which were attributed primarily to the hydrophilic corona of OEG brushes.

BackgroundIncreased platelet aggregation is implicated in the pathogenesis of ischemic stroke and anti-platelet strategy may contribute to its therapy. Panaxatriol saponin (PTS), the main components extracted from Panax notoginseng, has been shown to be efficacious in the prevention and treatment of ischemic stroke in China. The aim of this study is to determine the anti-platelet activity and explore the underlying mechanisms.MethodsInhibitory effect of PTS and its main ginsenosides on agonists-induced platelet aggregation was determined using rabbit or human platelets. Intracellular Ca2+ concentration ([Ca2+]i) mobilization was detected with fura-2/AM probe. MAPKs phosphorylation was determined by Western blotting.ResultsOur results showed PTS inhibited the rabbit platelet aggregation induced by various agonists (collagen, thrombin and ADP). The three main ginsenosides (Rg1, Re and R1) existing in PTS also showed anti-platelet activity, while their combination exhibited no synergistic effect on rabbit platelet aggregation. Further study demonstrated that PTS and its main ginsenosides also exhibited inhibitory effect on human platelet aggregation. Mechanism study demonstrated that pre-treatment with PTS inhibited the agonists-induced intracellular calcium mobilization. Moreover, PTS significantly suppressed the activation of both ERK2 and p38 by the agonists via reducing the phosphorylation of ERK2 and p38.ConclusionWe proved that PTS is effective in anti-platelet aggregation, which may, at least in part, be related to the suppression of intracellular calcium mobilization and ERK2/p38 activation. This study may provide one reasonable explanation for the efficacy of PTS on the prevention and treatment of ischemic stroke.

Panaxatriol saponins (PTS), the main components extracted from Panax notoginseng, have been shown to be efficacious in the prevention and treatment of cerebrovascular diseases in China. NF-E2-related factor 2 (Nrf2), a transcription factor regulating antioxidant and cytoprotective responses to oxidative stress, has received particular attention as a molecular target for pharmacological intervention of ischemic diseases. The aim of this study was to characterize the effect of PTS on the activation of Nrf2 signaling pathway and the potential role in its protective effect. We found that PTS induced heme oxygenase-1 (HO-1) expression in PC12 cells via activating Nrf2 signaling pathway. Phosphatidylinositol 3-kinase (PI3K)/Akt kinase was involved in the upstream of this PTS activated pathway. Moreover, combination of the main components in PTS significantly enhanced the expression of Nrf2 mediated phase II enzymes. Importantly, the protective effect of PTS against oxygen-glucose deprivation-reperfusion (OGD-Rep) induced cell death was significantly attenuated by PI3K inhibitor and antioxidant response element (ARE) decoy oligonucleotides, suggesting that both PI3K/Akt and Nrf2 signaling pathway are essential during this protective process. Taken together, our results suggest that PTS may activate endogenous cytoprotective mechanism against OGD-Rep induced oxidative injury via the activation of PI3K/Akt and Nrf2 signaling pathway.

By combining KLVFF peptide and self-assembly chaperone we fabricate a new system to achieve the synchronization between Aβ fibril disaggregation and reducing toxicity of Aβ fragments (monomers or oligomers) that consequently formed. When the KLVFF peptides disaggregate fibrils into fragments, the hydrophobic domains of self-assembly chaperones promptly bind them at the same time. This binding blocks the re-aggregation of the fragments and their interaction with cells, and hence reduces the toxicity of these dangerous fragments.

Detailed band structure calculations have been performed for Cd(2)Re(2)O(7) in high-, middle- and low-temperature (T) phases. The calculations are based on the observed lattice structures from x-ray diffraction measurements. The spin-orbit interaction is incorporated self-consistently in both the generalized gradient approximation (GGA) and the GGA plus Hubbard U (GGA+U) approaches. It is found that the on-site U has negligible effects on the Re 5d band structures; therefore both the GGA and GGA+U Re 5d band energies agree well with the observed O K-edge x-ray absorption spectroscopy (XAS) spectrum, whereas the Cd 4d band energy observed from photoemission spectroscopy can only be correctly reproduced by GGA+U calculations, indicating the relatively itinerant Re 5d and localized Cd 4d electrons. On the other hand, the spin-orbit coupling gives rise to nontrivial spin and orbital magnetic moments for the middle- T phase. Most unexpectedly, we found that the low- T phase exhibits quasi-two-dimensional Fermi surfaces. The calculated carrier numbers for the three phases are, at least qualitatively, consistent with the measured Hall coefficient.

An elegant integration of light-emitting segments into the structure of polymeric delivery systems endows the resulting self-assembled nanovehicles with the diagnostic ability toward an enhanced therapeutic efficiency. A variety of polyfluorene (PF)-based binary delivery systems were designed and developed successfully, but PF-based ternary formulations remain rarely explored, likely due to the synthetic challenge. To develop a universal synthesis strategy toward linear conjugated amphiphilic triblock copolymer for cancer theranostics, herein we focused on the functionalization of the PF terminus for further chain extension and prepared well-defined PF-based amphiphilic triblock copolymers, PF-bpoly(ε-caprolactone)-b-poly(oligo(ethylene glycol) monomethyl ether methacrylate) (PF-b-PCL-b-POEGMA), by integrated state-of-the-art polymer chemistry techniques, including Suzuki reaction, ring-opening polymerization, atom transfer radical polymerization, and click coupling. The resulting conjugated amphiphilic triblock copolymers can self-assembe into core−shell-corona (CSC) micelles with PF block constructing the inner hydrophobic core for fluorescent tracking, PCL segment forming the hydrophobic middle shell for drug encapsulation, and POEGMA moiety building the hydrophilic outer corona for particulate stabilization. Interestingly, the CSC micelles with hydrophobic PCL middle layer show a greater drug loading capacity as well as a higher fluorescence quantum yield (Φ) relative to the core−shell micelles self-assembled from the control of PF-b-POEGMA diblock copolymers without PCL sequence due to having more hydrophobic spaces and better separation of PF sequence provided simultaneously by the PCL central block. The efficient cellular uptake of the anticancer drug doxorubicin-loaded CSC micelles together with the in vitro cytotoxicity against the HeLa cells makes the conjugated amphiphilic triblock copolymers developed herein a promising platform for simultaneous cell image and drug delivery, thus offering great potential for cancer theranostics.