Inhalable spray-dried porous microparticles containing dehydroandrographolide succinate phospholipid complex capable of improving and prolonging pulmonary anti-inflammatory efficacy in mice.

Due to the unique physiological barriers within the lungs, there are considerable challenges in developing drug delivery systems enabling prolonged drug exposure to respiratory epithelial cells. Here, we report a PulmoSphere-based dry powder technology that incorporates a drug-phospholipid complex to promote intracellular retention of dehydroandrographolide succinate (DAS) in respiratory epithelial cells following pulmonary delivery. The DAS-phospholipid complex has the ability to self-assemble into nanoparticles. After spray-drying to produce PulmoSphere microparticles loaded with the drug-phospholipid complex, the rehydrated microparticles discharge the phospholipid complex without altering its physicochemical properties. The microparticles containing the DAS-phospholipid complex exhibit remarkable aerodynamic properties with a fine particle fraction of ∼ 60% and a mass median aerodynamic diameter of ∼ 2.3 µm. These properties facilitate deposition in the alveolar region. In vitro cell culture and lung tissue explants experiments reveal that the drug-phospholipid complex prolongs intracellular residence time and lung tissue retention due to the slow intracellular disassociation of drug from the complex. Once deposited in the lungs, the DAS-phospholipid complex loaded microparticles increase and extend drug exposure to the lung tissues and the immune cells compared to the free DAS counterpart. The improved drug exposure to airway epithelial cells, but not immune cells, is related to a prolonged duration of pulmonary anti-inflammation at decreased doses in a mouse model of acute lung injury induced by lipopolysaccharide. Overall, the phospholipid complex loaded microparticles present a promising approach for improved treatment of respiratory diseases, e.g. pneumonia and acute respiratory distress syndrome.

Discovery of hydroxamate as a promising scaffold dually inhibiting metallo- and serine-ß-lactamases.

The bacterial infection mediated by ß-lactamases MßLs and SßLs has grown into an emergent health threat, however, development of a molecule that dual inhibits both MßLs and SßLs is challenging. In this work, a series of hydroxamates 1a-g, 2a-e, 3a-c, 4a-c were synthesized, characterized by 1H and 13C NMR and confirmed by HRMS. Biochemical assays revealed that these molecules dually inhibited MßLs (NDM-1, IMP-1) and SßLs (KPC-2, OXA-48), with an IC50 value in the range of 0.64-41.08 and 1.01-41.91 µM (except 1a and 1d on SßLs, IC50 > 50 µM), and 1f was found to be the best inhibitor with an IC50 value in the range of 0.64-1.32 and 0.57-1.01 µM, respectively. Mechanism evaluation indicated that 1f noncompetitively and irreversibly inhibited NDM-1 and KPC-2, with Ki value of 2.5 and 0.55 µM, is a time- and dose-dependent inhibitor of both MßLs and SßLs. MIC tests shown that all hydroxamates increased the antimicrobial effect of MER on E. coli-NDM-1 and E. coli-IMP-1 (expect 1b, 1d, 1g and 2d), resulting in a 2-8-fold reduction in MICs of MER, 1e-g, 2b-d, 3a-c and 4b-c decreased 2-4-fold MICs of MER on E. coli-KPC-2, and 1c, 1f-g, 2a-c, 3b, 4a and 4c decreased 2-16-fold MICs of MER on E. coli-OXA-48. Most importantly, 1f-g, 2b-c, 3b and 4c exhibited the dual synergizing inhibition against both E. coli-MßLs and E. coli-SßLs tested, resulting in a 2-8-fold reduction in MICs of MER, and 1f was found to have the best effect on the drug-resistant bacteria tested. Also, 1f shown synergizing antimicrobial effect on five clinical isolates EC04, EC06, EC08, EC10 and EC24 that produce NDM-1, resulting in a 2-8-fold reduction in MIC of MER, but its effect on E. coli and K. pneumonia-KPC-NDM was not to be observed using the same dose of inhibitor. Mice tests shown that the monotherapy of 1f or 4a in combination with MER significantly reduced the bacterial load of E. coli-NDM-1 and E. coli-OXA-48 cells in liver and spleen, respectively. The discovery in this work offered a promising bifunctional scaffold for creating the specific molecules that dually inhibit MßLs and MßLs, in combating antibiotic-resistant bacteria.

Dihydroxyphenyl-substituted thiosemicarbazone: A potent scaffold for the development of metallo-ß-lactamases inhibitors and antimicrobial.

The superbug infection mediated by metallo-ß-lactamases (MßLs) has grown into anemergent health threat, and development of MßL inhibitors is an ideal strategy to combat the infection. In this work, twenty-five thiosemicarbazones 1a-e, 2a-e, 3a-e, 4a-d, 5a-d and 6a-b were synthesized and assayed against MßLs ImiS, NDM-1 and L1. The gained molecules specifically inhibited NDM-1 and ImiS, exhibiting an IC50 value in the range of 0.37-21.35 and 0.45-8.76 µM, and 2a was found to be the best inhibitor, with an IC50 of 0.37 and 0.45 µM, respectively, using meropenem (MER) as substrate. Enzyme kinetics and dialysis tests revealed and confirmed by ITC that 2a is a time-and dose-dependent inhibitor of ImiS and NDM-1, it competitively and reversibly inhibited ImiS with a Ki value of 0.29 µM, but irreversibly inhibited NDM-1. Structure-activity relationship disclosed that the substitute dihydroxylbenzene significantly enhanced inhibitory activity of thiosemicarbazones on ImiS and NDM-1. Most importantly, 1a-e, 2a-e and 3a-b alone more strongly sterilized E. coli-ImiS and E. coli-NDM-1 than the MER, displaying a MIC value in the range of 8-128 µg/mL, and 2a was found to be the best reagent with a MIC of 8 and 32 µg/mL. Also, 2a alone strongly sterilized the clinical isolates EC01, EC06-EC08, EC24 and K. pneumonia-KPC-NDM, showing a MIC value in the range of 16-128 µg/mL, and exhibited synergistic inhibition with MER on these bacteria tested, resulting in 8-32-fold reduction in MIC of MER. SEM images shown that the bacteria E. coli-ImiS, E. coli-NDM-1, EC24, K. pneumonia-KPC and K. pneumonia-KPC-NDM treated with 2a (64 µg/mL) suffered from distortion, emerging adhesion between individual cells and crumpled membranes. Mice tests shown that monotherapy of 2a evidently limited growth of EC24 cells, and in combination with MER, it significantly reduced the bacterial load in liver and spleen. Docking studies suggest that the 2,4-dihydroxylbenzene of 2a acts as zinc-binding group with the Zn(II) and the residual amino acids in CphA active center, tightly anchoring the inhibitor at active site. This work offered a promising scaffold for the development of MßLs inhibitors, specifically the antimicrobial for clinically drug-resistant isolates.

Fluticasone propionate nanosuspensions for sustained nebulization delivery: An in vitro and in vivo evaluation.

This study intended to investigate the in vivo pulmonary fate of intratracheally dosed nanosuspensions of fluticasone propionate (FP). Three FP suspensions, including a microsuspension and two nanosuspensions with different dissolution profiles, were prepared and they exhibited comparable aerodynamic performances after nebulization via a jet nebulizer. Following intratracheal administration to rats, the microsuspension underwent extensive mucociliary clearance, leading to a limited absorption time whereas the nanosuspensions decreased the mucociliary clearance and allowed dissolution rate-limiting and extended pulmonary absorption, resulting in prolonged pulmonary retention and long-acting anti-inflammatory efficacy in a lipopolysaccharide induced lung injury model. Delaying the FP dissolution of a nanosuspension by phospholipid coating increased AUC value in lung tissues to 1.72-fold of a conventional nanosuspension, but led to a decreased pharmacological efficacy. This study demonstrated that inhalable nanosuspensions were a feasible means for the sustained pulmonary delivery of FP and the local anti-inflammatory efficacy was highly dependent on the dissolution profiles.

Comparison of different fractionation strategies for in-depth phosphoproteomics by liquid chromatography tandem mass spectrometry.

Phosphorylation, a major posttranslational modification of proteins, plays an important role in protein activity and cell signaling. However, it is difficult to detect protein phosphorylation because of its low abundance and the fact that the analysis can be hindered by the presence of highly abundant non-phosphoproteins. In order to reduce the sample complexity and improve the efficiency of identification of phosphopeptides, aliphatic hydroxy acid-modified metal oxide chromatography (HAMMOC) was utilized to enrich phosphopeptides from a murine macrophage cell lysate. Strong cation chromatography (SCX), electrostatic repulsion hydrophilic interaction chromatography (ERLIC), and solution isoelectric focusing (sIEF) were investigated in detail for phosphopeptide fractionation strategies followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. A total of 5744 non-redundant phosphopeptides and 2159 phosphoproteins were identified from the cell lysates in three fractionation approaches. The SCX fractionation contained the largest number of phosphoproteins and phosphopeptides that were identified. In addition, 4336, 2064, and 2424 phosphopeptides were identified from SCX-LC-MS/MS, ERLIC-LC-MS/MS, and sIEF-LC/MS-MS, including 2430, 438, and 751 phosphopeptides that were only specifically found in SCX, ERLIC, and sIEF fractionations. In conclusion, these three fractionation strategies demonstrated great complementarity, which greatly improved the efficiency of identification of phosphopeptides and can be suitable for use in in-depth phosphoproteome research. Graphical Abstract.

Intracellular hydrogelation preserves fluid and functional cell membrane interfaces for biological interactions.

Cell membranes are an intricate yet fragile interface that requires substrate support for stabilization. Upon cell death, disassembly of the cytoskeletal network deprives plasma membranes of mechanical support and leads to membrane rupture and disintegration. By assembling a network of synthetic hydrogel polymers inside the intracellular compartment using photo-activated crosslinking chemistry, we show that the fluid cell membrane can be preserved, resulting in intracellularly gelated cells with robust stability. Upon assessing several types of adherent and suspension cells over a range of hydrogel crosslinking densities, we validate retention of surface properties, membrane lipid fluidity, lipid order, and protein mobility on the gelated cells. Preservation of cell surface functions is further demonstrated with gelated antigen presenting cells, which engage with antigen-specific T lymphocytes and effectively promote cell expansion ex vivo and in vivo. The intracellular hydrogelation technique presents a versatile cell fixation approach adaptable for biomembrane studies and biomedical device construction.

[DNA repair of CHL cells and HeLa cells after DNA damage induced by different oxidative agents].

OBJECTIVE: To investigate DNA repair in CHL cells and HeLa cells after DNA damage induced by different oxidative agents. METHODS: CHL cells and HeLa cells were exposed to various damaging agents, CHL cells: H(2)O(2) for 25 min, K(2)Cr(2)O(7) for 105 min, doxorubicin (Dox) for 75 min HeLa cells: H(2)O(2) for 25 min, K(2)Cr(2)O(7) for 105 min; then cells were continuously cultured for 0-3 h after washing. Alkaline single cell gel electrophoresis (ASCGE) assay was used to detect DNA strand breaks. RESULT: (1) DNA strand breaks were induced in CHL cells after exposure to H(2)O(2) K(2)Cr(2)O(7) or Dox, which were repaired evidently after continuous culture for 1 h(P<0.01). The damages induced by H(2)O(2) or K(2)Cr(2)O(7) were repaired completely after culture for 2-3 h. However, the demage induced by Dox was repaired incompletely. (2) DNA strand breaks were induced also in HeLa cells after exposure to H(2)O(2) or K(2)Cr(2)O(7), which were repaired evidently after continuous culture for 0.5 h(P<0.01),and completely after culture for 1 h. (3) The regression coefficient related to the rate of comet cells and repair time was statistically different (P<0.05) between CHL cells and HeLa cells. CONCLUSION: DNA damage induced by Dox is repaired more difficult than that induced by H(2)O(2) or K(2)Cr(2)O(7). The repair initiates immediately after DNA damage in both of cells, but more rapidly in HeLa cells than in CHL cells.