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Engineered outer membrane vesicles (OMVs) derived from Gram-negative bacteria are a promising technology for the creation of non-infectious, nanoparticle vaccines against diverse pathogens. However, antigen display on OMVs can be difficult to control and highly variable due to bottlenecks in protein expression and localization to the outer membrane of the host cell, especially for bulky and/or complex antigens. Here, we describe a universal approach for avidin-based vaccine antigen crosslinking (AvidVax) whereby biotinylated antigens are linked to the exterior of OMVs whose surfaces are remodeled with multiple copies of a synthetic antigen-binding protein (SNAP) comprised of an outer membrane scaffold protein fused to a biotin-binding protein. We show that SNAP-OMVs can be readily decorated with a molecularly diverse array of biotinylated subunit antigens, including globular and membrane proteins, glycans and glycoconjugates, haptens, lipids, and short peptides. When the resulting OMV formulations are injected in mice, strong antigen-specific antibody responses are observed that depend on the physical coupling between the antigen and SNAP-OMV delivery vehicle. Overall, these results demonstrate AvidVax as a modular platform that enables rapid and simplified assembly of antigen-studded OMVs for application as vaccines against pathogenic threats.

 

Abstract Objective The aim of this study was to evaluate the functional, systemic, synovial and articular changes after intra-articular administration of a synthetic lubricin within healthy canine stifles. Study Design A prospective randomized blinded placebo-controlled study composed of 10 dogs equally divided into either a treatment group (intra-articular synthetic lubricin injection, n = 5) or control group (saline, n = 5). Clinical (orthopaedic examination, gait observation, gait analysis), biochemical (complete blood count and biochemistry profile) and local tissue outcomes (joint fluid analysis, joint capsule and articular cartilage histopathology) were evaluated over a time period of 3 months. Results No significant differences between the treatment group and control group were identified with regard to baseline patient parameters. No clinically significant orthopaedic examination abnormalities, gait abnormalities, biochemical alterations, joint fluid alterations or histopathological alterations were identified over the course of the study. Conclusion The synthetic lubricin studied herein is both biocompatible and safe for a single administration within the canine stifle joint. Further research is necessary to evaluate the clinical efficacy of the synthetic lubricin in canine osteoarthritic joints. 

Low molecular weight substrates of the efflux transporter, P-glycoprotein, alter the biodistribution and tissue retention of nanoparticles following intravenous administration. Of particular interest is the retention of the targeted nanoparticles in the brain. Drug delivery to the brain is hindered by the restricted transport of drugs through the blood-brain barrier (BBB). Drugs that passively diffuse across the BBB also have large volumes of distribution; therefore, alteration of their biodistribution to increase their concentration in the brain may help to enhance efficacy and reduce off-target side effects. In this work, targeted nanoparticles were used to explore a new approach to target drugs to the brain--the exploitation of the P-glycoprotein efflux pump. The retention of nanoparticles containing a strong P-glycoprotein substrate, rhodamine 6G, tethered to a PLA nanoparticle through a PEG spacer was greater than two-fold relative to untargeted nanoparticles and to nanoparticles tethered to a weaker Pglycoprotein substrate, rhodamine 123. In a P-glycoprotein knockout mouse model (mdr1a (-/-)), there were no significant differences in brain accumulation between rhodamine 6G targeted particles and controls, strongly supporting the role of Pglycoprotein. This proof of concept report shows the potential applicability of low molecular weight P-gp substrates to alter nanoparticle biodistribution. 

We report the design of a diblock copolymer with architecture and function inspired by the lubricating glycoprotein lubricin. This diblock copolymer, synthesized by sequential reversible addition–fragmentation chain-transfer polymerization, consists of a cationic cartilage-binding domain and a brush-lubricating domain. It reduces the coefficient of friction of articular cartilage under boundary mode conditions (0.088 ± 0.039) to a level equivalent to that provided by lubricin (0.093 ± 0.011). Additionally, both the EC 50 (0.404 mg/mL) and cartilage-binding time constant (7.19 min) of the polymer are comparable to purified human and recombinant lubricin. Like lubricin, the tribological properties of this polymer are dependent on molecular architecture. When the same monomer composition was evaluated either as an AB diblock copolymer or as a random copolymer, the diblock effectively lubricated cartilage under boundary mode conditions whereas the random copolymer did not. Additionally, the individual polymer blocks did not lubricate independently, and lubrication could be competitively inhibited with an excess of binding domain. This diblock copolymer is an example of a synthetic polymer with lubrication properties equal to lubricin under boundary mode conditions, suggesting its potential utility as a therapy for joint pathologies like osteoarthritis. 

Determining what caused the global Last Glaciation and last glacial termination, despite opposing orbital summer insolation signatures between the polar hemispheres, remains a puzzle of paleoclimatology. This problem can be addressed by comparing chronologies of glaciation from different latitudes and different climatic regimes in both hemispheres. Here, we present a¹⁰Be surface‐exposure chronology of glacial landforms constructed during and since the local Last Glaciation in the continental environment of Central Asia in the high Mongolian Altai (49°N, 88°E). Four belts of lateral moraines document maximal phases of the former Khoton glacier at 35,440 ± 980 years ago, 23,430 ± 850 years ago, 20,780 ± 610 years ago, and 19,520 ± 550 years ago. Our chronology indicates that deglaciation from these maximal positions began as early as 18,810 ± 510 years ago, was well underway by 17,680 ± 510 years ago, and was nearly completed by 16,040 ± 490 years ago. Overall, our chronology shows that glaciation in western Mongolia overlapped with the global Last Glacial Maximum and that extensive recession from glacial‐to‐interglacial limits took place early in the last glacial termination during Heinrich Stadial 1. Khoton Nuur deglaciation led the demise of large Northern Hemisphere ice sheets and increases in radiative forcing agents by several millennia. We suggest that this rapid switch in the mode of glaciation implies the involvement of an additional climatic factor that could have produced locally rapid warming and deglaciation ∼18,800–16,000 years ago.

 

The molecular composition and architecture of polymeric DNA delivery reagents govern their transfection efficiency. One parameter that is understudied is the influence of polydispersity on transfection efficiency. Here we report the synthesis of two molecularly identical polymer series, but with different polydispersities (1.3 vs. 2.0) and quantify the effect polydispersity on transfection efficiency. The results show that the effect of polydispersity on transfection efficiency in cell culture is not predictable and is stochastic in nature. In general terms, polymers with high polydispersity mediated higher levels of transfectionin vitrocompared to low polydispersity polymers with the same side chain distribution and composition. However, at higher molecular weights, the effect of polydispersity was polymer specific, with enhanced transfection efficiency in some cases, but negligible in others. An interesting outcome is that the higher polydispersity polymers generally enhanced the stability of polymer:DNA complexes and this enhancement generally correlated with enhanced transfection efficiency. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2018,135, 45965.