Nanoerythropoietin is 10-times more effective than regular erythropoietin in neuroprotection in a neonatal rat model of hypoxia and ischemia.

BACKGROUND AND PURPOSE: Erythropoietin (EPO) has been demonstrated to possess significant neuroprotective effects in stroke. We determined if the nano-drug form of human recombinant EPO (PLGA-EPO nanoparticles [PLGA-EPO-NP]) can enhance neuroprotection at lower dosages versus human recombinant EPO (r-EPO). METHODS: Established neonatal rat model of unilateral ischemic stroke was used to compare r-EPO, PLGA-EPO-NP and phosphate-buffered saline, given by daily intraperitoneal injections, followed by infarction volume and Rotarod Performance Test assessment. RESULTS: PLGA-EPO-NP significantly reduced infarction volumes 72 hours after injury compared with the same concentrations of r-EPO. Functional deficits were significantly reduced by 300 U/kg PLGA-EPO-NP versus controls, with deficit attenuation apparent at significantly lower dosages of PLGA-EPO-NP versus r-EPO. CONCLUSIONS: PLGA-EPO-NP is neuroprotective and beneficial against deficits after brain ischemia, at significantly reduced dosages versus r-EPO.

Cytoplasmic Trafficking of Nanoparticles Delivers Plasmid DNA for Macrophage Gene-editing.

BACKGROUND: Successful delivery of gene-editing tools using nano-carriers is dependent on the ability of nanoparticles to pass through the cellular membrane, move through the cytoplasm, and cross the nuclear envelope to enter the nucleus. It is critical that intracellular nanoparticles interact with the cytoskeletal network to move toward the nucleus, and must escape degradation pathways including lysosomal digestion. Without efficient intracellular transportation and nuclear entry, nanoparticles-based gene-editing cannot be effectively used for targeted genomic modification. OBJECTIVE: We have developed nanoparticles with a low molecular weight branched polyethylenimine lipid shell and a PLGA core that can effectively deliver plasmid DNA to macrophages for gene editing while limiting toxicity. METHODS: Core-shell nanoparticles were synthesized by a modified solvent evaporation method and were loaded with plasmid DNA. Confocal microscopy was used to visualize the internalization, intracellular distribution and cytoplasmic transportation of plasmid DNA loaded nanoparticles (pDNA-NPs) in bone marrow-derived macrophages. RESULTS: Core-shell nanoparticles had a high surface charge of +56 mV and narrow size distribution. When loaded with plasmid DNA for transfection, the nanoparticles increased in size from 150 nm to 200 nm, and the zeta potential decreased to +36 mV, indicating successful encapsulation. Further, fluorescence microscopy revealed that pDNA-NPs crossed the cell membrane and interacted with actin filaments. Intracellular tracking of pDNA-NPs showed successful separation of pDNA- NPs from lysosomes, allowing entry into the nucleus at 2 hours, with further nuclear ingress up to 5 hours. Bone marrow-derived macrophages treated with pDNA/GFP-NPs exhibited high GFP expression with low cytotoxicity. CONCLUSION: Together, this data suggests pDNA-NPs are an effective delivery system for macrophage gene-editing.

Facile Gene Delivery Derived from Branched Low Molecular Weight Polyethylenimine by High Efficient Chemistry.

Convenient methods for the preparation of gene delivery platforms based on branched low molecular weight polyethylenimine (PEI) were described. Firstly, PEI lipids, with a low molecular weight PEI headgroup and hexadecyl chain tail group, were prepared through a highly efficient ring-opening reaction of glycidyl hexadecyl ether (EpoxyC16) by amine from PEI. Then, the PEI lipids were used as a component of cationic liposomes and as a surfactant for the preparation of poly(D,L-lactide-co-glycolide) (PLGA) nanoparticle (NP) via solvent extraction/evaporation method. As potential effective gene delivery platforms, their preparation, size, size distribution, toxicities, plasmid DNA loading, in vitro transfection and intracellular trafficking were studied. Both facile platforms showed less toxicity and higher transfection efficacy when compared to high molecular weight PEI in vitro, and may have further versatile applications in the gene delivery field.

Targeted delivery of nano-PTX to the brain tumor-associated macrophages.

Nanoparticles containing mixed lipid monolayer shell, biodegradable polymer core and rabies virus glycoprotein (RVG) peptide as brain targeting ligand, were developed for brain targeted delivery of paclitaxel (PTX) to treat malignant glioma. RVG conjugated PTX loaded NPs (RVG-PTX-NPs) had the desirable size (~140 nm), narrow size distribution and spherical shape. RVG-PTX-NPs showed poor uptake by neurons and selective targeting to the brain tumor associated macrophages (TAMs) with controlled release and tumor specific toxicity. In vivo studies revealed that RVG-PTX-NPs were significant to cross the blood-brain barrier (BBB) and had specific targeting to the brain. Most importantly, RVG-PTX-NPs showed effectiveness for anti-glioma therapy on human glioma of mice model. We concluded that RVG-PTX-NPs provided an effective approach for brain-TAMs targeted delivery for the treatment of glioma.