Nitric Oxide Release Research Articles

Assessment of acute toxicity, genotoxicity, and anti-inflammatory activity of SteLL, a lectin from Schinus terebinthifolia Raddi. Leaves, in mice

Ethnopharmacology relevanceSchinus terebinthifolia Raddi (Anacardiaceae), known as Brazilian pepper tree, stands out as a medicinal plant widely used in traditional medicine. The leaves are popularly used as anti-inflammatory agent and to relieve inflammatory conditions such as bronchitis, ulcers, and wounds, for example. Aim of the studyThe present study evaluated the acute toxicity, genotoxicity, and anti-inflammatory activity of S. terebinthifolia leaf lectin (SteLL) in mice (Mus musculus). Materials and methodsIn the acute toxicity assay, the animals were treated intraperitoneally (i.p.) or orally (per os) with a single dose of 100 mg/kg. Genotoxicity was assessed by the comet and micronucleus assays. Carrageenan-induced peritonitis and paw edema models were used to evaluate the anti-inflammatory effects of SteLL (1, 5 and 10 mg/kg, i.p.). ResultsNo animal died and no signs of intoxication or histopathological damage were observed in the acute toxicity assay. Genotoxic effect was not detected. In peritonitis assay, SteLL reduced in 56–69% leukocyte migration to the peritoneal cavity; neutrophil count decreased by 25–32%, while mononuclear cell count increased by 67–74%. SteLL promoted a notable reduction of paw edema after 4 h (61.1–63.4%). Morphometric analysis showed that SteLL also decreased the thickness of epidermal edema (30.2–40.7%). Furthermore, SteLL decreased MPO activity, plasma leakage, NO release, and modulated cytokines in both peritoneal fluid and paw homogenate. ConclusionSteLL did not induce acute toxicity or genotoxicity in mice and stands out as a promising candidate in the development of new phytopharmaceuticals with anti-inflammatory action.

NIR-light controlled local delivery of nitric oxide based on self-targeting carbon dots

Nitric oxide (NO)-based gas therapy has received ever-increasing attention in treatment of many diseases, especially cancer. However, the selective organelle targeted delivery and controllable release of NO remains highly desirable. In this work, a sequentially targeting delivery nanoplatform has been constructed by encapsulating heat-responsive S-nitrosocysteine (the NO donor, SNC) conjugated mitochondria-targeting carbon dots (MitoCDs) and indocyanine green (ICG) within liposomes which are further modified with aptamer that can specifically bind to nucleolin overexpressed on the surface of several cancer cells. MitoCDs were prepared via one-step hydrothermal reaction using citric acid and m-diethylaminophenol as starting materials and used without any external targeting molecules. ICG molecules were employed as NIR-triggered photothermal agent followed by NO precisely controlled release in mitochondria. By combining gas and photothermal treatment, the nanocarrier produced a synergistic and superior killing effect on several cancer cell lines. And the cell growth inhibition of NCL-CSI@Lip on HEp-2 cells raised up to 72.39 %. Such an ‘all-in-one’ mitochondria-targeted NO nanocarrier may lead to new way for overcoming the problem of multidrug resistance in intracellular drug delivery.

Metabolic flexibility ensures proper neuronal network function in moderate neuroinflammation

Microglia, brain-resident macrophages, can acquire distinct functional phenotypes, which are supported by differential reprogramming of cell metabolism. These adaptations include remodeling in glycolytic and mitochondrial metabolic fluxes, potentially altering energy substrate availability at the tissue level. This phenomenon may be highly relevant in the brain, where metabolism must be precisely regulated to maintain appropriate neuronal excitability and synaptic transmission. Direct evidence that microglia can impact on neuronal energy metabolism has been widely lacking, however. Combining molecular profiling, electrophysiology, oxygen microsensor recordings and mathematical modeling, we investigated microglia-mediated disturbances in brain energetics during neuroinflammation. Our results suggest that proinflammatory microglia showing enhanced nitric oxide release and decreased CX3CR1 expression transiently increase the tissue lactate/glucose ratio that depends on transcriptional reprogramming in microglia, not in neurons. In this condition, neuronal network activity such as gamma oscillations (30–70 Hz) can be fueled by increased ATP production in mitochondria, which is reflected by elevated oxygen consumption. During dysregulated inflammation, high energy demand and low glucose availability can be boundary conditions for neuronal metabolic fitness as revealed by kinetic modeling of single neuron energetics. Collectively, these findings indicate that metabolic flexibility protects neuronal network function against alterations in local substrate availability during moderate neuroinflammation.

Potential consequences of nitric oxide release: An improved model informing worker safety.

Both nitric oxide (NO) and nitrogen dioxide (NO2) gasses are toxic to humans but are commonly found in industrial settings such as semiconductor manufacturing sites. Due to the spontaneous oxidation of NO to NO2 under ambient conditions, individuals working with NO may in fact be exposed to both gasses in the case of an accidental release. Unfortunately, most safety materials provided to NO users do not address the potential for associated NO2 toxicity, and, until now, models developed to predict health consequences following a release of NO have not appropriately considered the oxidation kinetics nor the toxicity of both NO and NO2 in their assessments. This paper describes an improved multi-module model that addresses these limitations and explores whether facilities using NO should consider adopting measures that can mitigate the simultaneous health effects of both gasses. The model predicts the morbidity (intoxication/injury), mortality (death), and treatment outcomes that may arise following an industrial NO release by first calculating the doses of both NO and NO2 received by exposed individuals and then applying newly defined toxicity parameters for NO and NO2 to assign dose-dependent probabilities for the onset of intoxication and/or death and the ability of appropriate treatment(s) to save lives. Modeling results indicate low risk to worker health in the likeliest release scenarios while identifying less likely situations that carry substantially higher risk. Moreover, these results indicate that risks to worker health can be mitigated with simple measures like maintaining reliable alarms, adequate ventilation, and on-site supplies of methylene blue, as well as encouraging quick responses by personnel. With appropriate parameterization, the improved modeling framework is generalizable to any chemical release, especially multi-hazard releases resulting from the conversion of one toxic compound into another under likely environmental conditions. By directly addressing the toxicities of multiple compounds, the improved model presents a more realistic picture of the potential health consequences of a chemical release. This generalizable framework for modeling of multi-hazard chemical releases can inform preparedness and risk mitigation strategies for NO release events.

Anti-inflammatory effects of Olive (olea europaea L.) fruit extract in LPS-stimulated RAW264.7 cells via MAPK and NF-κB signal pathways.

Olive is an evergreen tree of Oleaceae Olea with numerous bioactive components. While the anti-inflammatory properties of olive oil and the derivatives are well-documented, there remains a dearth of in-depth researches on the immunosuppressive effects of olive fruit water extract. This study aimed to elucidate the dose-effect relationship and underlying molecular mechanisms of olive fruit extract in mediating anti-inflammatory responses. The impacts of olive fruit extract on the release of nitric oxide (NO), tumor necrosis factor (TNF-α), interleukins-6 (IL-6) and reactive oxygen species (ROS) were assessed in RAW264.7 cells induced by lipopolysaccharide (LPS). For deeper understanding, the expression of genes encoding inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), TNF-α and IL-6 was quantitatively tested. Additionally, the expression patterns of MAPK and NF-κB pathways were further observed to analyze the action mechanisms. Results suggested that olive fruit extract (200, 500, 1000µg/mL) markedly exhibited a dose-dependent reduction in the generation of NO, TNF-α, IL-6 and ROS, as well as the expression of correlative genes studied. The activation of ERK, JNK, p38, IκB-α and p65 were all suppressed when p65 nuclear translocation was further restricted by olive fruit extract in NF-κB and MAPK signal pathways. Olive fruit extract targeted imposing restrictions on the signal transduction of key proteins in NF-κB and MAPK pathways, and thereby lowered the level of inflammatory mediators, which put an enormous hindrance to inflammatory development. Accordingly, it is reasonable to consider olive fruit as a potent ingredient in immunomodulatory products.

Microbubble-encapsulated Cobalt Nitrato Complexes for Ultrasound-triggerable Nitric Oxide Delivery.

Cobalt complexes exhibit versatile reactivity with nitric oxide (NO), enabling their utilization in applications ranging from homogeneous catalysis to NO-based modulation of biological processes. However, the coordination geometry around the cobalt center is complex, the therapeutic window of NO is narrow, and controlled NO delivery is difficult. To better understand the complexation of cobalt with NO, we prepared four cobalt nitrato complexes and present a structure-property relationship for ultrasound-triggerable NO release. We hypothesized that modulation of the coordination geometry by ligand-modification would improve responsiveness to mechanical stimuli, like ultrasound. To enable eventual therapeutic testing, we here first demonstrate the in vitro tolerability of [Co(ethylenediamine)2(NO)(NO3)](NO3) in A431 epidermoid carcinoma cells and J774A.1 murine macrophages, and we subsequently show successful encapsulation of the complex in poly(butyl cyanoacrylate) microbubbles. These hybrid Co-NO-containing microbubbles may in the future aid in ultrasound imaging-guided treatment of NO-responsive vascular pathologies.

Accelerated Electron Ionization-Induced Changes in the Myenteric Plexus of the Rat Stomach.

The influence of accelerated electrons on neuronal structures is scarcely explored compared to gamma and X-rays. This study aims to investigate the effects of accelerated electron radiation on some pivotal neurotransmitter circuits (cholinergic and serotonergic) of rats' myenteric plexus. Male Wistar rats were irradiated with an electron beam (9 MeV, 5 Gy) generated by a multimodality linear accelerator. The contractile activity of isolated smooth muscle samples from the gastric corpus was measured. Furthermore, an electrical stimulation (200 μs, 20 Hz, 50 s, 60 V) was performed on the samples and an assessment of the cholinergic and serotonergic circuits was made. Five days after irradiation, the recorded mechanical responses were biphasic-contraction/relaxation in controls and contraction/contraction in irradiated samples. The nature of the contractile phase of control samples was cholinergic with serotonin involvement. The relaxation phase involved ACh-induced nitric oxide release from gastric neurons. There was a significant increase in serotonergic involvement during the first and second contractile phases of the irradiated samples, along with a diminished role of acetylcholine in the first phase. This study demonstrates an increased involvement of serotonergic neurotransmitter circuits in the gastric myenteric plexus caused by radiation with accelerated electrons.

Fabrication and Optimization of Poly(ε-caprolactone) Microspheres Loaded with S-Nitroso-N-Acetylpenicillamine for Nitric Oxide Delivery.

Heart disease is one of the leading causes of death in the United States and throughout the world. While there are different techniques for reducing or preventing the impact of heart disease, nitric oxide (NO) is administered as nitroglycerin for reversing angina or chest pain. Unfortunately, due to its gaseous and short-lived half-life, NO can be difficult to study or even administer. Therefore, controlled delivery of NO is desirable for therapeutic use. In the current study, the goal was to fabricate NO-releasing microspheres (MSs) using a donor molecule, S-Nitroso-N-Acetyl penicillamine, (SNAP), and encapsulating it in poly(ε-caprolactone) (PCL) using a single-emulsion technique that can provide sustained delivery of NO to cells over time without posing any toxicity risks. Optimization of the fabrication process was performed by varying the duration of homogenization (5, 10, and 20 min) and its effect on entrapment efficiency and size. The optimized SNAP-MS had an entrapment efficiency of ˃50%. Furthermore, we developed a modified method for NO detection by using NO microsensors to detect the NO release from SNAP-MSs in real time, showing sustained release behavior. The fabricated SNAP-MSs were tested for biocompatibility with HUVECs (human umbilical vein endothelial cells), which were found to be biocompatible. Lastly, we tested the effect of controlled NO delivery to human induced pluripotent stem-derived cardiomyocytes (hiPSC-CMs) via SNAP-MSs, which showed a significant improvement in the electrophysiological parameters and alleviated anoxic stress.

Platelet membrane coated Cu9S8-SNAP for NIR-II photoacoustic imaging guided NO repairing acute kidney injury

Acute kidney injury (AKI) is a prevalent critical condition in hospitalized patients with an elevated risk of death. Challenges in AKI management persist due to the absence of efficient early diagnostic modalities and the lack of effective therapeutic interventions, imposing significant burdens on medical resources for prolonged treatment. Here, we proposed a second near-infrared (NIR-II) photoacoustic imaging (PAI) guided triggered on-demand release of (nitric oxide) NO from the injury zone to monitor and treat AKI through the anti-inflammatory, anti-apoptotic, and oxidative stress-damage-reducing cell- or organ-protective effects of NO. We engineered hollow copper sulfide nanoparticles (Cu9S8 NPs) loaded with platelet membrane-encapsulated NO-releasing precursors (S-Nitroso-N-acetylpenicillamine, SNAP), as a nanoplatform for early AKI diagnosis and precise spatiotemporal NO release Besides acting as a drug carrier, the inherent PAI compatible Cu9S8 also enables targeted renal injury localization, exploiting the natural propensity of platelets to accumulate at vascular injury sites, facilitating real-time AKI monitoring in murine models. Experiments demonstrated that nitric oxide delivery nanoparticles can specifically target and accumulate in the kidney, reduce inflammation, and promote damage repair. Overall, this gas therapy strategy represents a new therapeutic pathway for the clinical AKI management.

Effects of nitric oxide on composition of the isolated essential oil from Satureja hortensis L. (Lamiaceae), under the cadmium stress

Cadmium (Cd) is one of the heavy metals that cause environmental pollution and biochemical changes in plants grown in contaminated soils. In plants, sodium nitroprusside is used as a nitric oxide (NO) release agent. In this research, a glasshouse pot experiment was conducted to examine the effect of exogenous NO on the essential oil composition of the savory plant, Satureja hortensis, under the Cd stress. For this, the plants were treated by different levels of Cd concentration including 0 (control), 75, 100, and 150 µM in the contaminated soil. Plants were also foliar sprayed with concentrations of 0 (control), 50, 100, and 200 µM NO. The results indicated that carvacrol was the main compound in all examined essential oils. Also, there were significant differences among the essential compounds under treatments of Cd and NO. Moreover, the differences among minor constituents were not significant in most of treatments. In apposite, carvacrol (approximately 60% of total volume) showed a significant difference than the others. The results indicated the role of exogenous agents on the changes of essential oil constituents in S. hortensis.

Discovery of 23,24-diols containing ergosterols with anti-neuroinflammatory activity from Penicillium citrinum TJ507

Citristerones A−E (1−5), five new 23,24-diols containing ergosterols, along with three known analogues, were isolated from the endophytic fungus Penicillium citrinum TJ507 obtained from Hypericum wilsonii N. Robson. Their structures and absolute configurations were determined by NMR, HRESIMS, Snatzke’s method, X-ray diffraction analyses and ECD calculation. Subsequently, the anti-neuroinflammatory effects of these isolates were screened using lipopolysaccharide (LPS)-induced BV-2 microglial cells, and citristerone B (2) showed outstanding anti-neuroinflammatory activity, with IC50 value of 0.60 ± 0.04 μM. Moreover, immunofluorescence and western blot analysis suggested that citristerone B not only reduced the release of nitric oxide (NO) and proinflammatory cytokines in LPS-induced BV-2 microglial cells, but also significantly inhibited the expression of TNF-α, iNOS and NF-κB, along with the production of cellular ROS.

Anti-Quenching NIR-II Excitation Phenylboronic Acid Modified Conjugated Polyelectrolyte for Intracellular Peroxynitrite-Enhanced Chemo-Photothermal Therapy.

Multidrug resistance to clinical chemotherapeutic drugs severely limits antitumor efficacy and patient survival. The integration of chemotherapy with photothermal therapy (PTT) and reactive nitrogen species has become a major strategy to enhance cancer treatment efficacy. Herein, a multifunctional peroxynitrite (ONOO-) nanogenerator (PBT/NO/Pt) for NIR-II fluorescence (NIR-II FL)/NIR-II photoacoustic (NIR-II PA) imaging-guided chemo/NIR-II PTT/ONOO- combination therapy is reported. The multifunction nanogenerator is developed by co-loading a pH-sensitive nitric oxide donor (DETA NONOate) and nicotinamide adenine dinucleotide phosphate oxidases trigger superoxide (O2 •-) generator chemotherapy drug (CDDP) to an NIR-II excitation-conjugated polyelectrolyte (PNC11BA). PNC11BA has non-conjugated alkyl chain segments in the polymer backbone and abundant positively charged phenylboronic acid in its side chains, which support the anti-quenching of NIR-II FL and the integration of DETA NONOate and CDDP into PBT/NO/Pt. In the acidic tumor microenvironment, the coordination bonds between CDDP and PNC11BA are cleaved, releasing CDDP for chemotherapeutic activity. The simultaneous release of nitric oxide (NO) and O2 •- rapidly leads to the in situ generation of the more cytotoxic reactive physiological nitrogen species ONOO-. In vitro and in vivo results prove that PBT/NO/Pt exhibited a markedly ONOO- enhanced chemo-photothermal synergistic therapy for SKOV3/DDP tumor by downregulating the intracellular glutathione and increasing CDDP-DNA adducts.

Polydopamine Nanocarriers with Cascade-Activated Nitric Oxide Release Combined Photothermal Activity for the Therapy of Drug-Resistant Bacterial Infections.

Antibiotic abuse leads to increased bacterial resistance, and the surviving planktonic bacteria aggregate and secrete extracellular polymers to form biofilms. Conventional antibacterial agents find it difficult to penetrate the biofilm, remove the bacteria wrapped in it, and produce an excellent therapeutic effect. In this study, a dual pH- and NIR-responsive nanocomposite (A-Ca@PDA) was developed to remove drug-resistant bacteria through a cascade of catalytic nitric oxide (NO) release and photothermal clearance. NO can melt in the outer package of the biofilm, facilitating the nanocomposites to have better permeability. Thermal therapy further inhibits the growth of planktonic bacteria. The locally generated high temperature and the burst release of NO together aggravate the biofilm collapse and bacterial death after NIR irradiation. The nanocomposites achieved a remarkable photothermal conversion efficiency of 47.5%, thereby exhibiting significant advancements in energy conversion. The nanocomposites exhibited remarkable efficacy in inhibiting multidrug-resistant (MDR) Escherichia coli and MDR Staphylococcus aureus, thus achieving an inhibition rate of >90%. Moreover, these nanocomposites significantly improved the wound-healing process in the MDR S. aureus-infected mice. Thus, this novel nanocomposite offers a novel strategy to combat drug-resistant bacterial infections.

Chemical composition and the anti-inflammatory effect of volatile compounds from Anaxagorea luzonensis A. Gray.

Anaxagorea luzonensis A. Gray, a member of the Annonaceae family, has been used to treat a variety of illnesses for a long time. For the first time, A. luzonensis volatile compounds (ALVCs) were extracted from the leaves,and the components were identified using gas chromatography-mass spectrometry (GC-MS). Further, the main compositions of ALVCs were also assessed for their ability to bind with anti-inflammatory proteins using a docking model. In addition, invitro tests e.g. inhibition of protein degradation and the inhibition of nitric oxide release using RAW264.7 macrophage cells were utilized for evaluating the anti-inflammatory activity. The results showed that the principal compounds of ALVCs were bulnesol (34.1 %), cubitene (17.8 %), β-eudesmol (10.4 %), epi-longipinanol (5.9 %), and (Z)-nerolidyl acetate (5.5 %). Three compounds viz. bulnesol, cubitene, and β-eudesmol bound firmly to cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX), as shown by the in silico analysis, similar to the positive control diclofenac. ALVCs effectively inhibited protein degradation with the IC50 of 31±2.3 μg/mL and inhibited nitric oxide production with the IC50 of 43.30±3.37 μg/mL. These findings showed that ALVCs might have a promising anti-inflammatory effect by blocking several inflammatory proteins.

Nitro-aniline based tripodal nitric oxide (NO) releasing molecule and light-triggered cytotoxicity in cancer cells

Trimesic acid-based novel tripodal nitric oxide (NO) donor Tris-NTA has been reported for the light-controlled NO release in organic and aqueous medium. Tris-NTA gradually releases NO in blue light (410 nm), the amount and rate of NO released can be easily modulated and controlled by merely varying the concentration of Tris-NTA and light. UV–Vis studies and Griess assay confirmed the effective steady and slow release of NO from the Tris-NTA. pH-dependent NO release studies confirm that NO release is relatively fast in at acidic medium compared to other conditions studied. Having three NO-releasing units in a single molecule, Tris-NTA was found to have a good quantum yield and fast NO release rate as compared to model compound 1 having only one NO donor. In vitro cytotoxicity tests demonstrate that the Tris-NTA is non-toxic to the cells up to the concentration of 20 μg/mL. However, Cell viability studies on human prostate cancer in the presence of light at different times suggest that the compound is toxic to the cancer cells DU145, only with light. The NO released from Tris-NTA is responsible for the cell death. Cytotoxicity result suggests that Tris-NTA could be a capable new NO donor for treating human prostate cancer.

Antileishmania, Immune Modulation and Apoptosis Induction by Astragalus ecbatanus Extract Against Leishmania tropica

Background: Due to the unique properties of Astragalus in treating diseases and strengthening the immune system, this study aimed to investigate, for the first time, the immune modulation and apoptosis induction by Astragalus ecbatanus extract against Leishmania tropica. Methods: The study assessed the in vitro efficacy of the Astragalus ecbatanus extract against both the promastigote and amastigote stages of L. tropica (MHOM/AF/88/KK27). Additionally, the effects of the extract on inducing nitric oxide (NO) release and its cytotoxicity on human macrophage cells were determined by calculating the 50% cytotoxic concentrations (CC50). The study also evaluated the Caspase-3-like activity in extract-treated parasites and conducted quantitative real-time PCR to assess the expression of genes associated with T lymphocytes. Results: Our study demonstrated that the A. ecbatanus extract significantly (P < 0.001) decreased the viability of both L. tropica promastigote and amastigote forms compared to the negative control. Moreover, the extract exhibited a high selectivity index (> 10), indicating its strong specificity towards intracellular parasites while showing low cytotoxicity to host cells. Our results indicated a dose-dependent upregulation of the expression levels of genes for inducible nitric oxide synthase (iNOS), interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNFα), and interleukin-10 (IL-10) in macrophages after exposure to A. ecbatanus ethyl acetate extract (P < 0.01). In contrast, the gene expression level of IL-10 exhibited a dose-dependent downregulation after exposure to A. ecbatanus ethyl acetate extract. We also found that the THP-1 macrophages exposed to the A. ecbatanus ethyl acetate extract exhibited enhanced production of nitric oxide (P < 0.001). Additionally, the ethyl acetate extract of A. ecbatanus significantly enhanced caspase-3 activation in Leishmania parasites (P < 0.01). Conclusions: The results demonstrated the significant impact of A. ecbatanus ethyl acetate extract on inhibiting and eradicating Leishmania parasites in laboratory settings. While some cellular mechanisms of action were identified, such as immune modulation and apoptosis induction against Leishmania parasites, further investigation is essential to elucidate the specific mechanisms of action and assess the efficacy in animal and human populations.

High‐Loading L‐Arginine Stabilized in an Oxygen‐Rich Lanthanide Metal–Organic Framework Capable of NO Release and Self‐Quantifying Luminescence Detection

AbstractExogenous supplementation of L‐arginine (L‐Arg) facilitates the release of nitric oxide (NO) for gas therapy applications in tumor microenvironments rich in H2O2. However, direct administration inevitably leads to the premature release of hydrophilic L‐Arg in the bloodstream, potentially resulting in unstable plasma L‐Arg concentrations and subsequent adverse reactions. Therefore, it is crucial to identify efficient and stable high‐dose L‐Arg delivery carriers, albeit challenging. Here, the study has achieved high (≈94 mg g−1) and stable L‐Arg loading within a 12‐coordinated Yb‐based lanthanide metal‐organic framework (named Yb‐DOBDC, where DOBDC is 2,5‐dihydroxyterephthalic acid). Yb‐DOBDC features size‐matched apertures and oxygen‐rich pore microenvironments, securely entrapping L‐Arg through electrostatic interactions and conjugation effects, thereby enhancing the biostability of the drug during delivery. In vitro experiments demonstrate that L‐Arg‐loaded Yb‐DOBDC (L‐Arg@Yb‐DOBDC) promotes NO release upon H2O2 stimulation, and the Yb‐DOBDC framework exhibits good biocompatibility within cells. More interestingly, the near‐infrared‐luminescence‐emitting Yb‐DOBDC exhibits a “turn‐off” behavior upon gradual loading of L‐Arg, enabling self‐quantifying luminescence detection during the encapsulation process. Consequently, the L‐Arg@Yb‐DOBDC system designed in this work, with its high/stable loading capacity and self‐quantifying luminescence detection capability, holds theoretical research value and potential practical application prospects.

Development of a nanozyme-based electrochemical catalyst for real-time biomarker sensing of superoxide and nitric oxide anions released from living cells and exogenous donors

Developing quantitative biosensors of superoxide (O2•−) and nitric oxide (NO) anion is crucial for pathological research. As of today, the main challenge for electrochemical detection is to develop high-selectivity nano-mimetic materials to replace natural enzymes. In this study, the dendritic-like morphological structure of silver organic framework (Ag-MOF) was successfully synthesized via a solvothermal strategy. Owing to the introduction of polymeric composites results in improved electrical conductivity and catalytic activity, which promotes mass transfer and leads to faster electron efficiency. For monitoring the electrochemical signals of O2•− and NO, the Ag-MOF electrode substrate was produced by drop-coating, and composites were designed by cyclic voltammetric potential cycles. The designed electrode substrates demonstrate high sensitivity, wide linear concentrations of 1 nM–1000 μM and 1 nM–850 μM, and low detection limits of 0.27 nM and 0.34 nM (S/N = 3) against O2•− and NO. Aside from that, the sensor successfully monitored the cellular release of O2•−, and NO from HepG2 and RAW 264.7 living cells and has the potential to monitor exogenous NO release from donors of Diethylamine (DEA)-NONOate and sodium nitroprusside (SNP). Additionally, the developed system was applied to the analysis of O2•− and NO in real biological fluid samples, and the results were good satisfactory (94.10–99.57 ± 1.23%). The designed system provides a novel approach to obtaining a good electrochemical biosensor platform that is highly selective, stable, and flexible. Finally, the proposed method provides a quantitative way to follow the dynamic changes in O2•− and NO in biological systems.

Role of Phenylethanolamine-N-methyltransferase on Nicotine-Induced Vasodilation in Rat Cerebral Arteries.

The sympathetic-parasympathetic (or axo-axonal) interaction mechanism mediated that neurogenic relaxation, which was dependent on norepinephrine (NE) releases from sympathetic nerve terminal and acts on β2-adrenoceptor of parasympathetic nerve terminal, has been reported. As NE is a weak β2-adrenoceptor agonist, there is a possibility that synaptic NE is converted to epinephrine by phenylethanolamine-N-methyltransferase (PNMT) and then acts on the β2-adrenoceptors to induce neurogenic vasodilation. Blood vessel myography technique was used to measure relaxation and contraction responses of isolated basilar arterial rings of rats. Nicotine-induced relaxation was sensitive to propranolol, guanethidine (an adrenergic neuronal blocker), and Nω-nitro-l-arginine. Nicotine- and exogenous NE-induced vasorelaxation was partially inhibited by LY-78335 (a PNMT inhibitor), and transmural nerve stimulation depolarized the nitrergic nerve terminal directly and was not inhibited by LY-78335; it then induced the release of nitric oxide (NO). Epinephrine-induced vasorelaxation was not affected by LY-78335. However, these vasorelaxations were completely inhibited by atenolol (a β1-adrenoceptor antagonist) combined with ICI-118,551 (a β2-adrenoceptor antagonist). These results suggest that NE may be methylated by PNMT to form epinephrine and cause the release of NO and vasodilation. These results provide further evidence supporting the physiological significance of the axo-axonal interaction mechanism in regulating brainstem vascular tone.

Musa basjoo Sieb polysaccharide improves inflammation in RAW264.7 cells and zebrafish colitis

Musa basjoo Sieb polysaccharide (MBSP) is the active ingredient of Musa basjoo Sieb. The purpose of this study was to preliminarily characterize the structural properties of MBSP, and to explore its ameliorating effect LPS-induced macrophage RAW264.7 inflammation and its therapeutic effect on DSS-induced zebrafish colitis. The data indicated that the average molecular weight of MBSP was 393.4 kDa, which was an acidic heteropolysaccharide composed of seven monosaccharides. In the LPS-induced macrophage RAW264.7 inflammation model, we found that MBSP significantly reduced the level of inflammatory mediators (p < 0.001). The release of NO, IL-6, and TNF-α was reduced by 48.21%, 65.45%, and 86.49%, respectively. And MBSP modulated intracellular ROS levels. This might be related to the activation of NF-κB/MAPK signaling pathway by MBSP. Additionally, MBSP significantly improved the oxidative stress status of UC zebrafish. SOD, CAT, GSH-Px were increased by 50.58%, 39.07% and 65.86%, and MDA, MPO were decreased by 26.00% and 50.98%, respectively (p < 0.001). Meanwhile, MBSP was also found to be effective in improving UC by activating the TLR4/NF-κB/MAPK signaling pathway in vivo. In conclusion, the present study characterized the structural properties of MBSP from various aspects, confirmed the anti-inflammatory effect of MBSP in vitro, and further verified the in vivo anti-inflammatory activity of MBSP using UC zebrafish as an animal model. The results of this study provide a reference for the development and application of MBSP in the field of treating inflammatory diseases.