Computational Design of Phosphotriesterase Improves V-Agent Degradation Efficiency.

Organophosphates (OPs) are a class of neurotoxic acetylcholinesterase inhibitors including widely used pesticides as well as nerve agents such as VX and VR. Current treatment of these toxins relies on reactivating acetylcholinesterase, which remains ineffective. Enzymatic scavengers are of interest for their ability to degrade OPs systemically before they reach their target. Here we describe a library of computationally designed variants of phosphotriesterase (PTE), an enzyme that is known to break down OPs. The mutations G208D, F104A, K77A, A80V, H254G, and I274N broadly improve catalytic efficiency of VX and VR hydrolysis without impacting the structure of the enzyme. The mutation I106 A improves catalysis of VR and L271E abolishes activity, likely due to disruptions of PTE's structure. This study elucidates the importance of these residues and contributes to the design of enzymatic OP scavengers with improved efficiency.

Self-Destructive Nanoscavengers Capture and Clear Neurotoxic Soluble ß-Amyloid Aggregates.

Cerebral soluble ß-amyloid aggregates (sAßs) accumulation is one of the most important causes in Alzheimer's disease (AD) progression. In order to mitigate the neurotoxicity induced by sAßs and achieve enhanced AD therapeutic outcomes, robust sAßs clearance become an emerging task. Herein, a self-destructive nanoscavenger (SDNS) is reported based on multifunctional peptide-polymer complexes that can capture extracellular sAßs via hydrogen-bonding interactions and deliver them into microglial lysosomes. The internalized SDNS then occurs self-destruction within lysosomes and upregulates autophagy, thereby promoting the degradation of neurotoxic sAßs. Importantly, the enhanced autophagy also significantly suppresses the secretion of inflammatory factors by microglia, which is induced by internalized sAßs. Given that cerebral persistent inflammatory environment disturbs microglia-mediated phagocytosis and degradation, it is believed that this synergistic approach has valuable potential as a therapeutic strategy for AD.

Dual-Modal Nanoscavenger for Detoxification of Organophosphorus Compounds.

Organophosphorus compounds (OPs) pose great military and civilian hazards. However, therapeutic and prophylactic antidotes against OP poisoning remain challenging. In this study, we first developed a novel nanoscavenger (rOPH/ZIF-8@E-Lipo) against methyl paraoxon (MP) poisoning using enzyme immobilization and erythrocyte-liposome hybrid membrane camouflage techniques. Then, we evaluated the physicochemical characterization, stability, and biocompatibility of the nanoscavengers. Afterward, we examined acetylcholinesterase (AChE) activity, cell viability, and intracellular reactive oxygen species (ROS) to indicate the protective effects of the nanoscavengers in vitro. Following the pharmacokinetic and biodistribution studies, we further evaluated the therapeutic and prophylactic detoxification efficacy of the nanoscavengers against MP in various poisoning settings. Finally, we explored the penetration capacity of the nanoscavengers across the blood-brain barrier (BBB). The present study validated the successful construction of a novel nanoscavenger with excellent stability and biocompatibility. In vitro, the resulting nanoscavenger exhibited a significant protection against MP-induced AChE inactivation, oxidative stress, and cytotoxicity. In vivo, apart from the positive therapeutic effects, the nanoscavengers also exerted significant prophylactic detoxification efficacy against single lethal MP exposure, repeated lethal MP challenges, and sublethal MP poisoning. These excellent detoxification effects of the nanoscavengers against OPs may originate from a dual-mode mechanism of inner recombinant organophosphorus hydrolase (rOPH) and outer erythrocyte membrane-anchored AChE. Finally, in vitro and in vivo studies jointly demonstrated that monosialoganglioside (GM1)-modified rOPH/ZIF-8@E-Lipo could penetrate the BBB with high efficiency. In conclusion, a stable and safe dual-modal nanoscavenger was developed with BBB penetration capability, providing a promising strategy for the treatment and prevention of OP poisoning.

A Size-Changeable Collagenase-Modified Nanoscavenger for Increasing Penetration and Retention of Nanomedicine in Deep Tumor Tissue.

The complex tumor microenvironment constitutes a variety of barriers to prevent nanoparticles (NPs) delivery and results in extremely low accumulation of nanomedicines in solid tumors. Here, a newly developed size-changeable collagenase-modified polymer micelle is employed to enhance the penetration and retention of nanomedicine in deep tumor tissue. The TCPPB micelle is first formed by self-assembly of maleimide-terminated poly(ethylene glycol)-block-poly(ß-amino ester) (MAL-PEG-PBAE) and succinic anhydride-modified cisplatin-conjugated poly(ε-caprolactone)-block-poly(ethylene oxide)-triphenylphosphonium (CDDP-PCL-PEO-TPP). Next, Col-TCPPB NPs are prepared through a "click" chemical combination of thiolated collagenase and maleimide groups on TCPPB micelle. Finally, biocompatible chondroitin sulfate (CS) is coated to obtain CS/Col-TCPPB NPs for avoiding collagenase inactivation in blood circulation. In tumor acidic microenvironment, the hydrophobic PBAE segments of the resultant micelles become hydrophilic, leading to a dissociation and subsequent dissolution of partial collagenase-containing components (Col-PEG-PBAE) from NPs. The dissolved Col-PEG-PBAE promotes the digestion of collagen fibers in tumor tissue like a scavenger, which enhances the NPs penetration. Simultaneously, the increased hydrophilicity of residual Col-PEG-PBAE in the micellar matrix causes an expansion of the NPs, resulting in an enhanced intratumoral retention. In tumor cells, the NPs target to release the cisplatin drugs into mitochondria, achieving an excellent anticancer efficacy.