Nitric oxide scavengers based on o-phenylenediamine for the treatment of rheumatoid arthritis.

Nitric oxide (NO) plays various physiologically favorable roles in the body. However, excessive production of NO causes inflammation and leads to various chronic inflammatory diseases. A typical NO-related disease is rheumatoid arthritis (RA), and it is well known that NO is a critical molecule for inflammation in the pathophysiology of RA. Therefore, depletion of NO can be an attractive treatment option for RA. In this study, we proposed a new method to discover effective NO scavengers in the form of small molecules. o-Phenylenediamine (o-PD), the core structure of the NO scavenger, is a diamino-aromatic compound that irreversibly reacts with NO through nucleophilic substitution of amine. Inspired by the nucleophilicity, we attempted to find new scavenger candidates by searching for conditions that increase the nucleophilicity of the amine moieties. Candidates were classified into the basic form o-PD, monoamine aniline, o-PD substituted with a nitro group, carboxyl group, and three methyl groups. The NO-scavenging ability of these candidates was demonstrated using the DAF-2 assay. N-Methyl-o-PD (N-Me) in the methyl (-CH3) group had the highest reactivity with NO among the candidates, and the efficiency of NO scavengers was confirmed in vitro and in vivo. Depleted levels of NO and reduced levels of pro-inflammatory cytokines by N-Me demonstrated remarkable therapeutic efficacy against joint damage and delayed severity in a collagen-induced arthritis (CIA) model. Therefore, our findings suggest that N-Me is a new NO scavenger with great potential for RA treatment and further clinical drug development.

Deep brain stimulation by blood-brain-barrier-crossing piezoelectric nanoparticles generating current and nitric oxide under focused ultrasound.

Deep brain stimulation via implanted electrodes can alleviate neuronal disorders. However, its applicability is constrained by side effects resulting from the insertion of electrodes into the brain. Here, we show that systemically administered piezoelectric nanoparticles producing nitric oxide and generating direct current under high-intensity focused ultrasound can be used to stimulate deep tissue in the brain. The release of nitric oxide temporarily disrupted tight junctions in the blood-brain barrier, allowing for the accumulation of the nanoparticles into brain parenchyma, and the piezoelectrically induced output current stimulated the release of dopamine by dopaminergic neuron-like cells. In a mouse model of Parkinson's disease, the ultrasound-responsive nanoparticles alleviated the symptoms of the disease without causing overt toxicity. The strategy may inspire the development of other minimally invasive therapies for neurodegenerative diseases.

Enzyme-Triggered Disassembly of Polymeric Micelles by Controlled Depolymerization via Cascade Cyclization for Anticancer Drug Delivery.

The high activity of specific enzymes in cancer has been utilized in cancer diagnosis, as well as tumor-targeted drug delivery. NAD(P)H:quinone oxidoreductase-1 (NQO1), an overexpressed enzyme in certain tumor types, maintains homeostasis and inhibits oxidative stress caused by elevated reactive oxygen species (ROS) in tumor cells. The activity of NQO1 in lung and liver cancer cells is increased compared to that in normal cells. Interestingly, NQO1 reacts with trimethyl-locked quinone propionic acid (QPA) and produces a lactone-based group via intramolecular cyclization. Toward this objective, we synthesized an amphiphilic block copolymer (QPA-P) composed of NQO1 enzyme-triggered depolymerizable QPA-locked polycaprolactone (PCL) and poly(ethylene glycol) (PEG) as hydrophobic and hydrophilic constituents, respectively. This QPA-P formed self-assembled micelles in aqueous conditions. It was observed that NQO1 catalyzed the depolymerization of QPA-locked PCL via a cascade two-step cyclization process, which eventually induced the dissociation of micellar structure and triggered the release of loaded drugs at the target cancer cells. Compared to the control group, the NQO1-responsive micelle showed NQO1-triggered intracellular drug release and enhanced anticancer effects. These results indicate that the NQO1-responsive polymeric micelles present a promising potential for improving therapeutic efficacy of an anticancer drug delivery system.

A Study on Hypoxia Susceptibility of Organ Tissues by Fluorescence Imaging with a Ratiometric Nitroreductase Probe.

Hypoxia, a condition of oxygen deficiency in tissues, features various diseases including solid tumor. Under hypoxia, several reductases such as nitroreductases are elevated. Based on this fact, we have investigated an indirect way to assess the hypoxia susceptibility of different organ tissues (mouse lung, heart, spleen, kidney, and liver) by detecting nitroreductase present within. Among the organs, the kidney showed a notable susceptibility to hypoxia, which was due to the renal medulla, not due to the renal cortex, as observed by ratiometric fluorescence imaging with a probe. The probe features ratiometric signaling, NIR-emitting, two-photon absorbing, and pH-insensitive emission properties, offering a practical tool for studying the nitroreductase activity and, furthermore, hypoxia-associated biological processes.

Harnessing the Formation of Natural Killer-Tumor Cell Immunological Synapses for Enhanced Therapeutic Effect in Solid Tumors.

The formation of an immunological synapse (IS) on recognition of a cancer cell is the main mechanism underlying the natural killer (NK)-cell-mediated killing of tumor cells. Herein, an integrative strategy for cancer therapy against solid tumors is reported, in which alterations in the cleft of IS, following the secretion of acidic granular content, are utilized as a trigger for the delivery of chemotherapeutic drugs. NK cells are decorated with the IS-environment-responsive micellar system to ensure the release of the payload when they attack cancer cells. Using this strategy, the immunological cytotoxic killing effect of NK cells against solid tumors is reinforced with the site-specific diffusion of chemotherapeutic agents. Harnessing the intrinsic mechanism for the recognition of abnormal cells and the tumor-homing effect of NK cells limit the adverse systemic effects of chemotherapeutic drugs. This approach may provide a pragmatic platform for the universal and effective utilization of IS formation.

Survey of Frontline Police Officers' Responses and Requirements in Psychiatric Emergency Situations.

Police officers in South Korea can be summoned to incidents involving individuals with mental health problems. Therefore, for officers to communicate effectively in such situations, education is necessary. Accordingly, this study obtained frontline police officers' perceptions of such educational programs and their suggestions regarding supplementary field manuals. Data were collected from 471 frontline police officers from 8 July until 9 August 2020. Data analysis incorporated frequency analysis, cross tabulation, text mining, and meaning network analysis. Participation in educational programs related to people with mental health problems depended on officers' field experience with such persons (χ2 = 7.432, p = 0.006). Among officers who received educational programs, most expressed satisfaction with the programs (χ2 = 72.243, p < 0.001) and believed that these facilitated problem-solving (χ2 = 7.574, p = 0.023), improved understanding of people with mental health problems (χ2 = 10.220, p = 0.006), enabled better communication with such individuals (χ2 = 21.588, p < 0.001), and improved confidence in clarity of verbal expression in conversations with them (χ2 = 6.634, p = 0.036). An on-site response manual for communicating with people with mental health problems would represent an effective educational intervention to improve police judgment and responses.

A cyotosol-selective nitric oxide bomb as a new paradigm of an anticancer drug.

We have reported rational design of a polymeric NO delivery micelle as a cytosol-selective NO bomb. Protected NO-donors are released from the micelle under endolysosomal conditions, and then deprotected by cytosolic glutathione. Cytosol-selective NO delivery facilitates significant tumor regression without the aid of other therapeutic modalities even in intravenous administrations.

Tumor vasodilation by N-Heterocyclic carbene-based nitric oxide delivery triggered by high-intensity focused ultrasound and enhanced drug homing to tumor sites for anti-cancer therapy.

Nitric oxide (NO) is widely known as an effective vasodilator at low concentrations. Drug delivery systems combined with NO can dilate blood vessels surrounding tumor tissues, and the drug accumulation in tumors is accelerated by the enhanced permeability and retention effect, leading to an improvement in the anti-tumor effect. N-heterocyclic carbene-based NO donors (e.g., 1,3-bis-(2,4,6-trimethylphenyl)imidazolylidene nitric oxide (IMesNO) have been developed for stable NO storing in air and water, and NO release by thermolysis. Herein, we demonstrated on-demand NO release by high-intensity focused ultrasound (HIFU) as a stimulus, which generated high heat and exerted an ablation effect when treated in vivo. We demonstrated IMesNO to be a HIFU-responsive NO donor and its potential application in vivo using IMesNO-loaded micelles. Moreover, IMesNO-loaded micelles mixed with drug-loaded micelles (IMesNO/DOX@MCs) showed acceleration of drug accumulation in tumor sites and enhanced tumor growth inhibition. Thus, our findings suggest a potential clinical bioapplication of NO-releasing drug-loaded micelles owing to the therapeutic function of NO and HIFU treatment for anti-cancer therapy.

Nitric Oxide-Scavenging Nanogel for Treating Rheumatoid Arthritis.

Nitric oxide (NO), a radical gas molecule produced by nitric oxide synthase, plays a key role in the human body. However, when endogenous NO is overproduced by physiological disorders, severe inflammatory diseases such as rheumatoid arthritis (RA) can occur. Therefore, scavenging NO may be an alternative strategy for treating inflammatory disorders. In our previous study, we developed a NO-responsive macrosized hydrogel by incorporating a NO-cleavable cross-linker (NOCCL); here, we further evaluate the effectiveness of the NO-scavenging nanosized hydrogel (NO-Scv gel) for treating RA. NO-Scv gel is simply prepared by solution polymerization between acrylamide and NOCCL. When the NO-Scv gel is exposed to NO, NOCCL is readily cleaved by consuming the NO molecule, as demonstrated in a Griess assay. As expected, the NO-Scv gel reduces inflammation levels by scavenging NO in vitro and shows excellent biocompatibility. Furthermore, the more promising therapeutic effect of the NO-Scv gel in suppressing the onset of RA is observed in vivo in a mouse RA model when compared to the effects of dexamethasone, a commercial drug. Therefore, our findings suggest the potential of the NO-Scv gel for biomedical applications and further clinical translation.

Programmed Nanoparticle-Loaded Nanoparticles for Deep-Penetrating 3D Cancer Therapy.

Tumors are 3D, composed of cellular agglomerations and blood vessels. Therapies involving nanoparticles utilize specific accumulations due to the leaky vascular structures. However, systemically injected nanoparticles are mostly uptaken by cells located on the surfaces of cancer tissues, lacking deep penetration into the core cancer regions. Herein, an unprecedented strategy, described as injecting "nanoparticle-loaded nanoparticles" to address the long-lasting problem is reported for effective surface-to-core drug delivery in entire 3D tumors. The "nanoparticle-loaded nanoparticle" is a silica nanoparticle (≈150 nm) with well-developed, interconnected channels (diameter of ≈30 nm), in which small gold nanoparticles (AuNPs) (≈15 nm) with programmable DNA are located. The nanoparticle (AuNPs)-loaded nanoparticles (silica): (1) can accumulate in tumors through leaky vascular structures by protecting the inner therapeutic AuNPs during blood circulation, and then (2) allow diffusion of the AuNPs for penetration into the entire surface-to-core tumor tissues, and finally (3) release a drug triggered by cancer-characteristic pH gradients. The hierarchical "nanoparticle-loaded nanoparticle" can be a rational design for cancer therapies because the outer large nanoparticles are effective in blood circulation and in protection of the therapeutic nanoparticles inside, allowing the loaded small nanoparticles to penetrate deeply into 3D tumors with anticancer drugs.

Doxorubicin/Ce6-Loaded Nanoparticle Coated with Polymer via Singlet Oxygen-Sensitive Linker for Photodynamically Assisted Chemotherapy.

It is widely known that the therapeutic effect of nanoparticle-based chemotherapeutics could be greatly enhanced by the introduction of the photodynamic effect. Herein we report a chlorin e6-incorporated mesoporous silica nanoparticles (MSNs) covered with a polyethylene glycol shell conjugated via a singlet oxygen-sensitive labile bis(alkylthio)alkene linker (CeAP-L-PEG). In this study, single irradiation with biocompatible red light induced both intracellular doxorubicin release and photochemical internalization, and consequently enhanced anti-cancer effect was observed in vitro and in vivo. This study suggests the potential of our precisely designed nanoparticle system for photodynamically assisted chemotherapy.

Self-assembled nanocomplex between polymerized phenylboronic acid and doxorubicin for efficient tumor-targeted chemotherapy.

Since the discovery that nano-scaled particulates can easily be incorporated into tumors via the enhanced permeability and retention (EPR) effect, such nanostructures have been exploited as therapeutic small molecule delivery systems. However, the convoluted synthetic process of conventional nanostructures has impeded their feasibility and reproducibility in clinical applications. Herein, we report an easily prepared formulation of self-assembled nanostructures for systemic delivery of the anti-cancer drug doxorubicin (DOX). Phenylboronic acid (PBA) was grafted onto the polymeric backbone of poly(maleic anhydride). pPBA-DOX nanocomplexes were prepared by simple mixing, on the basis of the strong interaction between the 1,3-diol of DOX and the PBA moiety on pPBA. Three nanocomplexes (1, 2, 4) were designed on the basis of [PBA]:[DOX] molar ratios of 1:1, 2:1, and 4:1, respectively, to investigate the function of the residual PBA moiety as a targeting ligand. An acid-labile drug release profile was observed, owing to the intrinsic properties of the phenylboronic ester. Moreover, the tumor-targeting ability of the nanocomplexes was demonstrated, both in vitro by confocal microscopy and in vivo by fluorescence imaging, to be driven by an inherent property of the residual PBA. Ligand competition assays with free PBA pre-treatment demonstrated the targeting effect of the residual PBA from the nanocomplexes 2 and 4. Finally, the nanocomplexes 2 and 4, compared with the free DOX, exhibited significantly greater anti-cancer effects in vitro and even in vivo. Our pPBA-DOX nanocomplex enables a new paradigm for self-assembled nanostructures with potential biomedical applications.

Self-Assembled Nanoconstructs Modified with Amplified Aptamers Inhibited Tumor Growth and Retinal Vascular Hyperpermeability via Vascular Endothelial Growth Factor Capturing.

Here, nanoconstructs consisting of a DNA-amplified aptamer with a biocompatible polymer backbone for capturing target biomolecules are presented. First, the polymer-DNA nanoconstructs were prepared by hybridization of two complementary single-stranded DNAs that were each conjugated to a dextran polymer backbone. The designed polymer-DNA amplified aptamer nanoconstructs (PA-aNCs) were then prepared by utilizing polymer-DNA nanoconstructs conjugated with an aptamer (PA-NCs) using a rolling circle amplification reaction to amplify the aptamer. These PA-aNCs were successfully applied to alleviate tumor growth and vascular endothelial growth factor (VEGF)-induced retinal vascular hyperpermeability in vivo through the highly effective capture of human VEGF as a target molecule. These PA-aNCs could be used as therapeutic agent for anti-VEGF therapy by efficiently capturing human VEGF.

Remission of lymphoblastic leukaemia in an intravascular fluidic environment by pliable drug carrier with a sliding target ligand.

A polyrotaxane-based nanoconstruct with pliable structure carrying a chemotherapeutic drug was developed for targeting circulating lymphoblastic leukaemia cells in a fluidic environment of blood vessels in vivo. By introducing lymphoblast targeting aptamer DNA through cyclodextrin, threaded in poly(ethylene glycol) as polyrotaxane, target aptamer slides along the long polymeric chain and actively search for target ligand, leading to active targeting in dynamic fluidic system which is enhanced by up to 6-fold compared with that of control carriers with non-sliding targeting ligands. Moreover, the drug carrier was made stimuli-responsive by employing i-motif DNA to selective releases of its payload at intracellular acidic condition. These combined features resulted in the effective remission of lymphoblastic leukaemia both in vitro and in dynamic blood vessels in vivo.

Andrographolide-loaded polymerized phenylboronic acid nanoconstruct for stimuli-responsive chemotherapy.

Along with the successful discovery of paclitaxel as an anticancer drug, natural products have drawn great attention in drug discovery. Recently, andrographolide (AND) from Andrographis paniculata was reported to provide several benefits, including an anticancer effect. However, the extremely low solubility of the compound in an aqueous medium was an obstacle to overcome for the systemic administration and clinical application of AND. Based on our previous report, we formulated a water-soluble nanoconstruct by forming a boronic ester between the cis-1,3-diol of AND with hydrophilically polymerized phenylboronic acid (pPBA). The release of loaded AND was controlled by intracellular conditions, specifically, by low pH and high ATP concentrations, due to the pH- and diol-dependent affinity of the boronic ester. Because of the intrinsic property of the PBA moiety, the pPBA-AND nanoconstruct exhibited an excellent tumor targeting ability both in vitro and in vivo. Finally, a significant inhibition of tumor growth was observed in vivo. Taken together, our strategy, which is based on the formulation of a soluble nanoconstruct using hydrophilically polymerized PBA and a cis-diol, is plausible and provides a delivery system for a wide variety of chemotherapeutics. This strategy has applications not only in cancer therapy but also broader fields such as anti-inflammation or immunotherapy.

Coordinative Amphiphiles as Tunable siRNA Transporters.

In this study, we developed coordinative amphiphiles for use as novel siRNA transporters. As a modification of a conventional cationic lipid structure, we replaced the cationic head with zinc(II)-dipicolylamine complex (Zn/DPA) as a phosphate-directing group, and used various membrane-directing groups in the place of the hydrophobic tails. These simple amphiphiles are readily synthesized and easy to modify. The Zn/DPA head groups bind to the phosphate backbones of siRNAs, and to our surprise, they prevented the enzymatic degradation of siRNAs by RNase A. Interestingly, the Zn/DPA head itself exhibited moderate transfection efficiency, and its combination with a membrane-directing group-oleoyl (CA1), pyrenebutyryl (CA2), or biotin (CA3)-enhanced the delivery efficiency without imparting significant cytotoxicity. Notably, the uptake pathway was tunable depending on the nature of the membrane-directing group. CA1 delivered siRNAs mainly through caveolae-mediated endocytosis, and CA2 through clathrin- and caveolin-independent endocytosis; CA3 recruited siRNAs specifically into biotin receptor-positive HepG2 cells through receptor-mediated endocytosis. Thus, it appears possible to develop tunable siRNA transporters simply by changing the membrane-directing parts. These are the first examples of amphiphilic siRNA transporters accompanying coordinative interactions between the amphiphiles and siRNAs.

Polydopamine Hollow Nanoparticle Functionalized with N-diazeniumdiolates as a Nitric Oxide Delivery Carrier for Antibacterial Therapy.

A biocompatible nitric oxide (NO) delivery nanoplatform, whose structure is a hollow nanoparticle composed of polydopamine backbone and diazeniumdiolates functional groups, is developed for antibacterial therapy. This platform liberates high NO quantitis and exerts the antibacterial activity with excellent biocompatibility thus being promising for treating bacterial infections.

Poly-paclitaxel/cyclodextrin-SPION nano-assembly for magnetically guided drug delivery system.

This work demonstrates the development of magnetically guided drug delivery systems and its potential on efficient anticancer therapy. The magnetically guided drug delivery system was successfully developed by utilizing superparamagnetic iron oxide nanoparticle, ß-cyclodextrin, and polymerized paclitaxel. Multivalent host-guest interactions between ß-cyclodextrin-conjugated superparamagnetic iron oxide nanoparticle and polymerized paclitaxel allowed to load the paclitaxel and the nanoparticle into the nano-assembly. Clusterized superparamagnetic iron oxide nanoparticles in the nano-assembly permitted the rapid and efficient targeted drug delivery. Compared to the control groups, the developed nano-assembly showed the enhanced anticancer effects in vivo as well as in vitro. Consequently, the strategy of the use of superparamagnetic nanoparticles and multivalent host-guest interactions has a promising potential for developing the efficient drug delivery systems.

Phenylboronic acid-sugar grafted polymer architecture as a dual stimuli-responsive gene carrier for targeted anti-angiogenic tumor therapy.

We present a cationic polymer architecture composed of phenylboronic acid (PBA), sugar-installed polyethylenimine (PEI), and polyethylene glycol (PEG). The chemical bonding of PBA with the diol in the sugar enabled the crosslinking of low-molecular-weight (MW) PEI to form high-MW PEI, resulting in strong interaction with anionic DNA for gene delivery. Inside the cell, the binding of PBA and sugar was disrupted by either acidic endosomal pH or intracellular ATP, so gene payloads were released effectively. This dual stimuli-responsive gene release drove the polymer to deliver DNA for high transfection efficiency with low cytotoxicity. In addition, PBA moiety with PEGylation facilitated the binding of polymer/DNA polyplexes to sialylated glycoprotein which is overexpressed on the tumor cell membrane, and thus provided high tumor targeting ability. Therapeutic application of our polymer was demonstrated as an anti-angiogenic gene delivery agent for tumor growth inhibition. Our judicious designed polymer structure based on PBA provides enormous potential as a gene delivery agent for effective gene therapy by stimuli-responsiveness and tumor targeting.

Nitric oxide-releasing polymer incorporated ointment for cutaneous wound healing.

This work demonstrates the development of nitric oxide-releasing ointment and its potential on efficient wound healing. Nitric oxide-releasing polymer was successfully synthesized, which is composed of biocompatible Pluronic F127, branched polyethylenimine and 1-substituted diazen-1-ium-1,2-diolates. The synthesized nitric oxide-releasing polymer was incorporated into the PEG-based ointment which not only facilitated nitric oxide release in a slow manner, but also served as a moisturizer to enhance the wound healing. As compared to control groups, the nitric oxide-releasing ointment showed the accelerated wound closure with enhanced re-epithelialization, collagen deposition, and blood vessel formation in vivo. Therefore, this nitric oxide-based ointment presents the promising potential for the efficient strategy to heal the cutaneous wound.