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Resolution is an active process that protects the host damage from inflammation responses induced by infections. Simultaneously resolving inflammation and eliminating pathogens may be effective to treat infectious diseases, but it is required to deliver therapeutics to infectious sites. Here, we proposed a strategy to incorporate RvD1 and an antibiotic (ceftazidime) in human neutrophil-membrane derived nanovesicles that can specifically target inflamed vasculature for treatment of lung infection caused by P. aeruginosa. Using the nitrogen cavitation method, we generated liposome-like nanovesicles from human neutrophil membrane. The results showed that nanovesicles loaded with RvD1 decreased cytokine levels and neutrophil lung infiltration, thus shortening the resolution intervals of lung inflammation. When RvD1 and ceftazidime were co-loaded in nanovesicles, they alleviated both inflammation and bacterial growth in the mouse lung. The studies reveal a new strategy to treat infectious diseases by designing nanoparticles to simultanesouly target host inflammatory pathways and pathogens.

Ischemic stroke is an acute and severe neurological disease, resulting in disability and death. Reperfusion to an ischemic brain is a means to reverse brain damage after stroke; however, this causes secondary tissue damage induced by inflammation responses, called ischemia/reperfusion (I/R) injury. Adhesion of neutrophils to endothelial cells underlies the initiation of inflammation in I/R. Inspired by this interaction, we report a drug delivery system comprised of neutrophil membrane-derived nanovesicles loaded with Resolvin D2 (RvD2) that can enhance resolution of inflammation, thus protecting brain damage during ischemic stroke. In the study, the middle cerebral artery occlusion (MCAO) mouse model was developed to mimic ischemic stroke. Using intravital microscopy of a live mouse brain, we visualized the binding of nanovesicles to inflamed brain vasculature for delivery of therapeutics to ischemic stroke lesions in real-time. We also observed that RvD2-loaded nanovesicles dramatically decreased inflammation in ischemic stroke and improved mouse neurological functions. Our study provides a strategy to inhibit neuroinflammation using neutrophil-derived nanovesicles for ischemic stroke therapy.

Extracellular vesicles (EVs) are cell membrane-derived compartments that regulate physiology and pathology in the body. Naturally secreted EVs have been well studied in their biogenesis and have been exploited in targeted drug delivery. Due to the limitations on production of EVs, nitrogen cavitation has been utilized to efficiently generate EV-like drug delivery systems used in treating inflammatory disorders. In this short review, we will discuss the production and purification of EVs, and we will summarize what technologies are needed to improve their production for translation. We describe the drug-loading processes in EVs and their applications as drug delivery systems for inflammatory therapies, focusing on a new type of EVs made from neutrophil membrane using nitrogen cavitation.

Extracellular vesicles (EVs) are nanoscale membrane-formed compartments naturally secreted from cells, which are intercellular mediators regulating physiology and pathogenesis, therefore they could be a novel therapeutic carrier for targeted delivery. However, the translation of EVs is hindered by the heterogeneous composition, low yield, inefficient drug loading and unlikely scalability. Here we report a strategy to generate EVs using nitrogen cavitation (NC-EVs) that instantly disrupts neutrophils to form nanosized membrane vesicles. NC-EVs are similar to naturally secreted EVs (NS-EVs), but contain less subcellular organelles and nuclear acids. The production of NC-EVs was increased by 16 folds and is easy to scale up for clinical use compared to NS-EVs. To examine the usefulness of NC-EVs as a drug delivery platform, piceatannol (an anti-inflammation drug) was remotely loaded in NC-EVs via the pH gradient. We found that piceatannol-loaded NC-EVs dramatically alleviated acute lung inflammation/injury and sepsis induced by lipopolysaccharide (LPS). Our studies reveal that nitrogen cavitation is a novel approach to efficiently generate EVs from any cell type and could be exploited for personalized nanomedicine., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Nanotechnology has become a powerful tool to potentially translate nanomedicine from bench to bedside. Nanotherapeutics are nanoparticles (NPs) loaded with drugs and possess the property of tissue targeting after surfaces of NPs are bio-functionalized. Designing smaller size of nanotherapeutics is presumed to increase tumor targeting based on the EPR (enhanced permeability and retention) effect. Since the immune systems possess a defence mechanism to fight diseases, there is an emerging concept that NPs selectively target immune cells to mediate the active delivery of drugs into sites of disease. In this review, we will focus on a key question of how nanotherapeutics specifically target immune cells and hijack them as a delivery vehicle to transport nanotherapeutics into disease tissues, thus possibly improving current therapies in inflammation, immune disorders and cancers. We will also discuss the challenges and opportunities for this new strategy of leukocyte-mediated delivery of nanotherapeutics., Competing Interests: Competing Interests: The authors have declared that no competing interest exists.

Inflammatory diseases such as acute lung injury and ischaemic tissue injury are caused by the adhesion of a type of white blood cell--polymorphonuclear neutrophils--to the lining of the circulatory system or vascular endothelium and unchecked neutrophil transmigration. Nanoparticle-mediated targeting of activated neutrophils on vascular endothelial cells at the site of injury may be a useful means of directly inactivating neutrophil transmigration and hence mitigating vascular inflammation. Here, we report a method employing drug-loaded albumin nanoparticles, which efficiently deliver drugs into neutrophils adherent to the surface of the inflamed endothelium. Using intravital microscopy of tumour necrosis factor-α-challenged mouse cremaster post-capillary venules, we demonstrate that fluorescently tagged albumin nanoparticles are largely internalized by neutrophils adherent to the activated endothelium via cell surface Fcɣ receptors. Administration of albumin nanoparticles loaded with the spleen tyrosine kinase inhibitor, piceatannol, which blocks 'outside-in' β2 integrin signalling in leukocytes, detached the adherent neutrophils and elicited their release into the circulation. Thus, internalization of drug-loaded albumin nanoparticles into neutrophils inactivates the pro-inflammatory function of activated neutrophils, thereby offering a promising approach for treating inflammatory diseases resulting from inappropriate neutrophil sequestration and activation.

Biofunctionalization of nanoparticles (NPs) is an essential component in targeted drug delivery. However, current nanotechnology remains inadequate to imitate complex intercellular interactions existing in physiological conditions in human bodies. Emerging concepts have been explored to utilize human cells to generate cell membrane-formed NPs because cells retain inherent abilities to interact with human tissues compared with synthetic nanomaterials. Neutrophils, red blood cells (RBCs), platelets and monocytes have been employed to form therapeutic NPs to treat vascular disease and cancer, and these novel drug delivery platforms show the translation potential to improve patient quality of life. In this review, we will discuss the concept of cell membrane-formed NPs, the molecular mechanisms of their disease targeting and the potential of personalized nanomedicine. [ABSTRACT FROM AUTHOR]

Lung bacterial infections could result in acute lung inflammation/injury (ALI) that propagates to its severe form, acute respiratory distress syndrome (ADRS) leading to the death. The molecular mechanism of ALI is associated with bacterial invasion and the host inflammation response. Here, we proposed a novel strategy to specifically target both bacteria and inflammatory pathways by co-loading of antibiotics (azlocillin, AZ) and anti-inflammatory agents (methylprednisolone sodium, MPS) in neutrophil nanovesicles. We found that cholesterol infilling in the membrane of nanovesicles can maintain a pH gradient between intra-vesicles and outer-vesicles, so we remotely loaded both AZ and MPS in single nanovesicles. The results showed that loading efficiency of both drugs can achieve more than 30% (w/w), and delivery of both drugs using nanovesicles accelerated bacterial clearance and resolved inflammation responses, thus preventing the potential lung damage due to infections. Our studies show that remote loading of multiple drugs in neutrophil nanovesicles which specifically target the infectious lung could be translational to treat ARDS. [ABSTRACT FROM AUTHOR]