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Brain, guarded by the most rigorous barrier — blood‐brain barrier (BBB), is the most critical and sophisticated control center in the body. The dead bodies from melanoma cells, small apoptotic bodies with membrane embedded CD44v6 molecules could pass through BBB and deliver drugs for the cure of Parkinson's disease. The apoptotic body might be a new type of carrier for efficient in vivo drug delivery. More details can be found in article number 2004929 by Chunming Wang, Junfeng Zhang, Lei Dong, and co‐workers. [Image: see text]

The blood‐brain barrier (BBB) is the most restrictive and complicated barrier that keeps most biomolecules and drugs from the brain. An efficient brain delivery strategy is urgently needed for the treatment of brain diseases. Based on the studies of brain‐targeting extracellular vesicles (EVs), the potential of using small apoptotic bodies (sABs) from brain metastatic cancer cells for brain‐targeting drug delivery is explored. It is found that anti‐TNF‐α antisense oligonucleotide (ASO) combined with cationic konjac glucomannan (cKGM) can be successfully loaded into sABs via a transfection/apoptosis induction process and that the sABs generated by B16F10 cells have an extraordinarily high brain delivery efficiency. Further studies suggest that ASO‐loaded sABs (sCABs) are transcytosed by b. End3 (brain microvascular endothelial cells, BMECs) to penetrate the BBB, which is mediated by CD44v6, and eventually taken up by microglial cells in the brain. In a Parkinson's disease (PD) mouse model, sCABs dramatically ameliorate PD symptoms via the anti‐inflammatory effect of ASO. This study suggests that sABs from brain metastatic cancer cells are excellent carriers for brain‐targeted delivery, as they have not only an extraordinary delivery efficiency but also a much higher scale‐up production potential than other EVs., Cancer cells that spread to the brain naturally produce nano‐sized “apoptotic bodies” (ABs), which can package nucleic acid drugs efficiently (>21.3%), cross the brain‐blood barrier via transcytosis mediated by CD44v6 exposed on ABs, and deliver anti‐inflammatory nucleotides into microglial cells. These ABs show potential as carriers for the treatment and diagnosis of brain diseases.

Endotoxins are found almost everywhere and possess high toxicity in vivo and in vitro. Here we design a novel boronate affinity material, called boronic acid-functionalized mesoporous silica-coated core/shell magnetic microspheres (Fe3O4@nSiO2@mSiO2-BA) with large pores (pore size > 20 nm) based on the chemical structure and physical properties of endotoxins, for facile and highly efficient removal of endotoxins. Dual modes for endotoxin removal were proposed and confirmed in this work: the endotoxin aggregates with size 20 nm) were absorbed on the outer surface of the prepared material based on boronate affinity. Transmission electron microscopy (TEM), X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms and Fourier transform infrared (FT-IR) spectroscopy confirm that Fe3O4@nSiO2@mSiO2-BA microspheres possess core/shell structure, uniform diameter (520 nm), high surface area (205.57 m2/g), large mesopores (21.8 nm) and boronic acid ligands. The purification procedures of Fe3O4@nSiO2@mSiO2-BA microspheres for endotoxin were optimized, and 50 mM NH4HCO3 (pH 8.0) and 0.05 M fructose were selected as loading/washing, elution buffers, respectively. The binding capacity of Fe3O4@nSiO2@mSiO2-BA microspheres for endotoxin was calculated to be 60.84 EU/g under the optimized conditions. Finally, the established analytical method was applied to remove endotoxins from plasmid DNA. After endotoxin removal, the endotoxin content in plasmid DNA was reduced from 0.0026 to 0.0006 EU/mL for two-fold concentration, and from 0.0088 to 0.0022 EU/mL for five-fold concentration after binding, respectively. Additional advantages of the prepared boronate affinity material include excellent stability, reusability/repeatability, and low cost. Boronate affinity materials with large pores could thus prove to be powerful adsorbents for endotoxin removal and the potential applications in the aspects of biological research, pharmaceutical industry, and life health.

Methanol intolerance of lipase is a major limitation in lipase-catalyzed methanolysis reactions. In this study, to understand the molecular mechanism of methanol-induced inactivation of lipases, we performed molecular dynamics (MD) simulations of Thermomyces lanuginosus lipase (TLL) in water and methanol and compared the observed structural and dynamic properties. The solvent accessibility analysis showed that in methanol, polar residues tended to be buried away from the solvent while non-polar residues tended to be more solvent-exposed in comparison to those in water. Moreover, we observed that in methanol, the van der Waals packing of the core residues in two hydrophobic regions of TLL became weak. Additionally, the catalytically relevant hydrogen bond between Asp201 OD2 and His258 ND1 in the active site was broken when the enzyme was solvated in methanol. This may affect the stability of the tetrahedral intermediates in the catalytic cycle of TLL. Furthermore, compared to those in water, some enzyme surface residues displayed enhanced movement in methanol with higher Cα root-mean-square atomic positional fluctuation values. One of such methanol-affecting surface residues (Ile241) was chosen for mutation, and MD simulation of the I241E mutant in methanol was conducted. The structural analysis of the mutant showed that replacing a non-polar surface residue with an acidic one at position 241 contributed to the stabilization of enzyme structure in methanol. Ultimately, these results, while providing molecular-level insights into the destabilizing effect of methanol on TLL, highlight the importance of surface residue redesign to improve the stability of lipases in methanol environments.

Erv1 (essential for respiration and viability 1) is a FAD-dependent sulphydryl oxidase with a tryptophan-rich catalytic domain. We show that Trp95 and Trp183 are important for stabilizing the folding, FAD-binding, and function of Erv1, whilst other four tryptophan residues are not functionally important., Erv1 is an FAD-dependent thiol oxidase of the ERV (essential for respiration and viability)/ALR (augmenter of liver regeneration) sub-family and an essential component of the mitochondrial import and assembly pathway. Erv1 contains six tryptophan residues, which are all located in the highly conserved C-terminal FAD-binding domain. Though important structural roles were predicted for the invariable Trp95, no experimental study has been reported. In the present study, we investigated the structural and functional roles of individual tryptophan residues of Erv1. Six single tryptophan-to-phenylalanine yeast mutant strains were generated and their effects on cell viability were tested at various temperatures. Then, the mutants were purified from Escherichia coli. Their effects on folding, FAD-binding and Erv1 activity were characterized. Our results showed that Erv1W95F has the strongest effect on the stability and function of Erv1 and followed by Erv1W183F. Erv1W95F results in a decrease in the Tm of Erv1 by 23°C, a significant loss of the oxidase activity and thus causing cell growth defects at both 30°C and 37°C. Erv1W183F induces changes in the oligomerization state of Erv1, along with a pronounced effect on the stability of Erv1 and its function at 37°C, whereas the other mutants had no clear effect on the function of Erv1 including the highly conserved Trp157 mutant. Finally, computational analysis indicates that Trp95 plays a key role in stabilizing the isoalloxazine ring to interact with Cys133. Taken together, the present study provided important insights into the molecular mechanism of how thiol oxidases use FAD in catalysing disulfide bond formation.

In this study molecular modelling is introduced as a novel approach for the development of pharmaceutical solid dispersions. A computational model based on quantum mechanical (QM) calculations was used to predict the miscibility of various drugs in various polymers by predicting the binding strength between the drug and dimeric form of the polymer. The drug/polymer miscibility was also estimated by using traditional approaches such as Van Krevelen/Hoftyzer and Bagley solubility parameters or Flory Huggins interaction parameter in comparison to the molecular modelling approach. The molecular modelling studies predicted successfully the drug-polymer binding energies and the preferable site of interaction between the functional groups. The drug-polymer miscibility and the physical state of bulk materials, physical mixtures and solid dispersions were determined by thermal analysis (DSC/MTDSC) and X-ray diffraction. The produced solid dispersions were analysed by X-ray photoelectron spectroscopy (XPS), which confirmed not only the exact type of the intermolecular interactions between the drug-polymer functional groups but also the binding strength by estimating the N-coefficient values. The findings demonstrate that QM-based molecular modelling is a powerful tool to predict the strength and type of intermolecular interactions in a range of drug/polymeric systems for the development of solid dispersions.