N-Acetyl Cysteine-Decorated Nitric Oxide-Releasing Interface for Biomedical Applications.

Biomedical devices are vulnerable to infections and biofilm formation, leading to extended hospital stays, high expenditure, and increased mortality. Infections are clinically treated via the administration of systemic antibiotics, leading to the development of antibiotic resistance. A multimechanistic strategy is needed to design an effective biomaterial with broad-spectrum antibacterial potential. Recent approaches have investigated the fabrication of innately antimicrobial biomedical device surfaces in the hope of making the antibiotic treatment obsolete. Herein, we report a novel fabrication strategy combining antibacterial nitric oxide (NO) with an antibiofilm agent N-acetyl cysteine (NAC) on a polyvinyl chloride surface using polycationic polyethylenimine (PEI) as a linker. The designed biomaterial could release NO for at least 7 days with minimal NO donor leaching under physiological conditions. The proposed surface technology significantly reduced the viability of Gram-negative Escherichia coli (>97%) and Gram-positive Staphylococcus aureus (>99%) bacteria in both adhered and planktonic forms in a 24 h antibacterial assay. The composites also exhibited a significant reduction in biomass and extra polymeric substance accumulation in a dynamic environment over 72 h. Overall, these results indicate that the proposed combination of the NO donor with mucolytic NAC on a polymer surface efficiently resists microbial adhesion and can be used to prevent device-associated biofilm formation.

NIR-activated electrospun nanodetonator dressing enhances infected diabetic wound healing with combined photothermal and nitric oxide-based gas therapy.

Diabetic wounds pose a challenge to healing due to increased bacterial susceptibility and poor vascularization. Effective healing requires simultaneous bacterial and biofilm elimination and angiogenesis stimulation. In this study, we incorporated polyaniline (PANI) and S-Nitrosoglutathione (GSNO) into a polyvinyl alcohol, chitosan, and hydroxypropyltrimethyl ammonium chloride chitosan (PVA/CS/HTCC) matrix, creating a versatile wound dressing membrane through electrospinning. The dressing combines the advantages of photothermal antibacterial therapy and nitric oxide gas therapy, exhibiting enduring and effective bactericidal activity and biofilm disruption against methicillin-sensitive Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Escherichia coli. Furthermore, the membrane's PTT effect and NO release exhibit significant synergistic activation, enabling a nanodetonator-like burst release of NO through NIR irradiation to disintegrate biofilms. Importantly, the nanofiber sustained a uniform release of nitric oxide, thereby catalyzing angiogenesis and advancing cellular migration. Ultimately, the employment of this membrane dressing culminated in the efficacious amelioration of diabetic-infected wounds in Sprague-Dawley rats, achieving wound closure within a concise duration of 14 days. Upon applying NIR irradiation to the PVA-CS-HTCC-PANI-GSNO nanofiber membrane, it swiftly eradicates bacteria and biofilm within 5 min, enhancing its inherent antibacterial and anti-biofilm properties through the powerful synergistic action of PTT and NO therapy. It also promotes angiogenesis, exhibits excellent biocompatibility, and is easy to use, highlighting its potential in treating diabetic wounds.

Penile erection and cardiovascular function: effects and pathophysiology.

Penile erection (PE) is a hemodynamic event that results from a neuroendocrine process, and it is influenced by the cardiovascular status of the patient. However, it may also modulate an individual's cardiovascular events. The present study provides the mechanisms involved in the association of PE and cardiovascular function. Erection upsurges the cardiac rate, blood pressure, and oxygen uptake. Sex-enhancing strategies, such as phosphodiesterase inhibitors, alprostadil, and testosterone also promote vasodilatation and cardiac performance, thus preventing myocardial infarction. More so, drugs that are used in the treatment of hypertensive heart diseases (such as angiotensin system inhibitors and ß-blockers) facilitate vasodilatation and PE. These associations have been linked with nitric oxide- and testosterone-dependent enhancing effects on the vascular endothelium. In addition, impaired cardiovascular function may negatively impact PE; therefore, impaired PE may be a pointer to cardiovascular pathology. Hence, evaluation of the cardiovascular status of an individual with erectile dysfunction (ED) is essential. Also, employing strategies that are used in maintaining optimal cardiac function may be useful in the management of ED.

Immunological studies on the effects of toltrazuril and neem extract in broiler chickens suffering from coccidiosis.

Background: The prevalence of avian coccidiosis in the poultry industry has grown, resulting in substantial financial losses from high mortality, stunted growth, reduced productivity, and expensive medical expenses. Aim: The purpose of the current study was to assess the immunological effects of neem leaf extract and toltrazuril on broilers that had contracted coccidiosis. Methods: In this investigation, 100 one-day-old Cobb broiler chicks without sexes were employed. The chicks were divided into five equal groups, with 20 birds in each. On the 14th day of life, the birds in groups 2, 3, 4, and 5 received an oral inoculation with 1 × 105 sporulated oocysts of Eimeria tenella (E. tenella) (field isolate). The first group (Gp), which consists of 20 healthy broilers, served as a negative control. Gp (2) contains experimentally infected broilers and nontreated (served as a positive control). Gp (3) contains experimentally infected broilers treated with toltrazuril (1 ml/l drinking water) for two consecutive days. Gp (4) contains experimentally infected broilers treated with neem leaf extract 4% (50 ml/l drinking water) for 5 successive days, and Gp (5) contains experimentally infected broilers treated with toltrazuril (1 ml/l drinking water) and a half dose of neem leaves extract 4% (25 ml/l drinking water) for 5 successive days. For the purpose of estimating body weight growth and feed conversion ratio, each broiler was weighed separately at the start of the trial and again on the 1st and 10th day after treatment. In addition to obtaining intestinal samples for immunohistochemistry, blood samples were also obtained for immunological examination. Results: As compared to the negative control group, the experimentally infested broilers with E. tenella showed significant decreases in serum nitric oxide, lysosome, phagocytic percent, and phagocytic index, along with significant increases in white blood cells (WBCs), lymphocyte, heterophilis, eosinophilis, basophilis, monocyte, serum total protein, γ globulin, fibrinogen, and haptoglobin. When compared to the control positive group, experimentally infested broilers treated with either neem or toltrazuril alone or in combination demonstrated significant increases in serum total protein, nitric oxide, lysozyme, phagocytic percent, and phagocytic index, but significant decreases in WBCs, lymphocytes, heterophile, eosinophile, basophile, and monocyte. The intestinal peroxidase stain of broilers infected with E. tenella exhibited a significant positive expression for CD4, but the infected broilers treated with toltrazuril and half a dosage of neem displayed a negative expression for CD4, identical to the negative control. Conclusion: The broiler chickens infested with E. tenella may have a variety of negative impacts on their immune systems and immunohistopathological findings. Nonetheless, toltrazuril and neem extract, either separately or in combination, function as anticoccidial medications that may enhance the broiler chicks' immune state.

Photodynamic and nitric oxide therapy-based synergistic antimicrobial nanoplatform: an advanced root canal irrigation system for endodontic bacterial infections.

BACKGROUND: The main issues faced during the treatment of apical periodontitis are the management of bacterial infection and the facilitation of the repair of alveolar bone defects to shorten disease duration. Conventional root canal irrigants are limited in their efficacy and are associated with several side effects. This study introduces a synergistic therapy based on nitric oxide (NO) and antimicrobial photodynamic therapy (aPDT) for the treatment of apical periodontitis. RESULTS: This research developed a multifunctional nanoparticle, CGP, utilizing guanidinylated poly (ethylene glycol)-poly (ε-Caprolactone) polymer as a carrier, internally loaded with the photosensitizer chlorin e6. During root canal irrigation, the guanidino groups on the surface of CGP enabled effective biofilm penetration. These groups undergo oxidation by hydrogen peroxide in the aPDT process, triggering the release of NO without hindering the production of singlet oxygen. The generated NO significantly enhanced the antimicrobial capability and biofilm eradication efficacy of aPDT. Furthermore, CGP not only outperforms conventional aPDT in eradicating biofilms but also effectively promotes the repair of alveolar bone defects post-eradication. Importantly, our findings reveal that CGP exhibits significantly higher biosafety compared to sodium hypochlorite, alongside superior therapeutic efficacy in a rat model of apical periodontitis. CONCLUSIONS: This study demonstrates that CGP, an effective root irrigation system based on aPDT and NO, has a promising application in root canal therapy.

Effects of Goose Astrovirus Type 2 Infection on Peripheral Blood Lymphocyte and Macrophage Activity In Vitro.

Goose astrovirus type 2 (GAstV-2) is a novel pathogen causing visceral gout in goslings; it not only causes necrosis of renal epithelial cells but also causes spleen damage, indicating that GAstV-2 induces immunosuppression in goslings. However, to date, the interaction between GAstV-2 and immune cells remains unclear. In this study, peripheral blood lymphocytes and macrophages were isolated from goslings without GAstV-2 infection and then inoculated in vitro with GAstV-2, and the virus localization in the lymphocytes and macrophages, proliferation and apoptosis of lymphocytes, and phagocytic activity, reactive oxygen species (ROS) and nitric oxide (NO) production, and cell polarity in macrophages were determined. The results showed that GAstV-2 was observed in the cytoplasm of CD4 and CD8 T cells and macrophages, indicating that GAstV-2 can infect both lymphocytes and macrophages. GAstV-2 infection reduced the lymphocyte proliferation induced by Concanavalin A and lipopolysaccharide stimulation and increased the lymphocyte apoptosis rate and mRNA expression of Fas, demonstrating that GAstV-2 causes damage to lymphocytes. Moreover, GAstV-2 infection enhanced phagocytic activity and production of ROS and NO and induced a proinflammatory phenotype in macrophages (M1 macrophages), indicating that macrophages play an antiviral role during GAstV-2 infection. In conclusion, these results demonstrate that GAstV-2 infection causes damages to lymphocytes, and host macrophages inhibit GAstV-2 invasion during infection.

Inhibition of superoxide and iNOS augment cutaneous nitric oxide-dependent vasodilation in non-Hispanic black young adults.

We assessed the combined effect of superoxide and iNOS inhibition on microvascular function in non-Hispanic Black and non-Hispanic White participants (n = 15 per group). Participants were instrumented with four microdialysis fibers: (1) lactated Ringer's (control), (2) 10 µM tempol (superoxide inhibition), (3) 0.1 mM 1400 W (iNOS inhibition), (4) tempol + 1400 W. Cutaneous vasodilation was induced via local heating and NO-dependent vasodilation was quantified. At control sites, NO-dependent vasodilation was lower in non-Hispanic Black (45 ± 9% NO) relative to non-Hispanic White (79 ± 9% NO; p < 0.01; effect size, d = 3.78) participants. Tempol (62 ± 16% NO), 1400 W (78 ± 12% NO) and tempol +1400 W (80 ± 13% NO) increased NO-dependent vasodilation in non-Hispanic Black participants relative to control sites (all p < 0.01; d = 1.22, 3.05, 3.03, respectively). The effect of 1400 W (p = 0.04, d = 1.11) and tempol +1400 W (p = 0.03, d = 1.22) was greater than tempol in non-Hispanic Black participants. There was no difference between non-Hispanic Black and non-Hispanic White participants at 1400 W or tempol + 1400 W sites. These data suggest iNOS has a greater effect on NO-dependent vasodilation than superoxide in non-Hispanic Black participants.

A novel multifunctional microneedle patch for synergistic photothermal- gas therapy against maxillofacial malignant melanoma and associated skin defects.

Considering the high recrudescence and the long-lasting unhealed large-sized wound that affect the aesthetics and cause dysfunction after resection of maxillofacial malignant skin tumors, a groundbreaking strategy is urgently needed. Photothermal therapy (PTT), which has become a complementary treatment of tumors, however, is powerless in tissue defect regeneration. Therefore, a novel multifunctional sodium nitroprusside and Fe2+ ions loaded microneedles (SNP-Fe@MNs) platform was fabricated by accomplishing desirable NIR-responsive photothermal effect while burst releasing nitric oxide (NO) after the ultraviolet radiation for the ablation of melanoma. Moreover, the steady releasing of NO in the long term by the platform can exert its angiogenic effects via upregulating multiple related pathways to promote tissue regeneration. Thus, the therapeutic dilemma caused by postoperative maxillofacial skin malignancies could be conquered through promoting tumor cell apoptosis via synergistic PTT-gas therapy and subsequent regeneration process in one step. The bio-application of SNP-Fe@MNs could be further popularized based on its ideal bioactivity and appealing features as a strategy for synergistic therapy of other tumors occurred in skin.

Platelet rich plasma alleviates endometritis induced by lipopolysaccharide in mice via inhibiting TLR4/NF-κB signaling pathway.

BACKGROUND: Endometritis is an inflammatory reaction of the lining of uterus, leading to the occurrence of infertility. Platelet rich plasma (PRP) has been proven to exhibit extremely effective for the treatment of endometrium-associated infertility, but the mechanism of its prevention for endometritis remains unclear. OBJECTIVE: The present study aimed to investigate the protective effect of PRP against endometritis induced by lipopolysaccharide (LPS) and elucidate the mechanism underlying these effects. METHODS: Mouse model of endometritis was established by intrauterine perfusion of LPS. PRP intrauterine infusion was administered at 24 h after LPS induction. After another 24 h, the uterine tissues were harvested to observe histopathological changes, production of proinflammatory cytokines, variation of the Toll-like receptor 4/nuclear factor κB (TLR4/NF-κB) signaling pathways, and validated the anti-inflammatory effect of PRP. The myeloperoxidase (MPO) activity and concentration of nitric oxide (NO) were determined using assay kit. Proinflammatory chemokines (tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), and interleukin-6 (IL-6)) were measured by ELISA and Real-Time PCR. The activity of TLR4/NF-κB pathway in uterine tissues was measured by Western blotting. RESULTS: Hematoxylin-eosin staining (H&E) appeared that PRP remarkably relieved the impairment of uterine tissues. Detection of MPO activity and concentration of NO revealed that PRP treatment distinctly mitigated infiltration of inflammatory cells in mice with endometritis induced by LPS. PRP treatment significantly affected the expression of TNF-α, IL-1ß, and IL-6. PRP was also found to suppress LPS-induced activation of TLR4/NF-κB pathway. CONCLUSION: PRP effectively alleviates LPS-induced endometritis via restraining the signal pathway of TLR4/NF-κB. These findings provide a solid foundation for PRP as a potential therapeutic agent for endometritis.

Ultrasound-driven radical chain reaction and immunoregulation of piezoelectric-based hybrid coating for treating implant infection.

The poor efficiency of US-responsive coatings on implants restricts their practical application. Immunotherapy that stimulates immune cells to enhance their antibacterial activity is expected to synergize with sonodynamic therapy for treating implant infection effectively and safely. Herein, US-responsive hybrid coatings composed of the oxygen-deficient BaTiO3 nanorod arrays and l-arginine (BaTiO3-x/LA) are designed and prepared on titanium implants for sonocatalytic therapy-cooperated immunotherapy to treat Methicillin-resistant Staphylococcus aureus (MRSA) infection. BaTiO3-x/LA can generate more oxidizing reactive oxygen species (ROS, hydroxyl radical (·OH)) and reactive nitrogen species (RNS, peroxynitrite anion (ONOO-)). The construction of nanorod arrays and oxygen defects balances the piezoelectric properties and sonocatalytic capability during US treatment. The generated piezoelectric electric field provides a sufficient driving force to separate electrons and holes, and the oxygen defects attenuate the electron-hole recombination efficiency, consequently increasing the yield of ROS during the US treatment. Moreover, nitric oxide (NO) released by l-arginine reacts with the superoxide radical (·O2-) to produce ONOO-. Since, this radical chain reaction improves the oxidizing ability between bacteria and radicals, the cell membrane (argB, secA2) and DNA (dnaBGXN) are destroyed. The bacterial self-repair mechanism indirectly accelerates bacterial death based on the transcriptome analysis. In addition to participating in the radical chain reaction, NO positively affects macrophage M1 polarization to yield potent phagocytosis to MRSA. As a result, without introducing an extra sonosensitizer, BaTiO3-x/LA exhibits excellent antibacterial activity against MRSA after the US treatment for 15 min. Furthermore, BaTiO3-x/LA facilitates macrophage M2 polarization after implantation and improves osteogenic differentiation. The combined effects of sonodynamic therapy and immunoregulation lead to an effective and safe treatment method for implant-associated infections.

Liquid plasma promotes angiogenesis through upregulation of endothelial nitric oxide synthase-induced extracellular matrix metabolism: potential applications of liquid plasma for vascular injuries.

BACKGROUND: Applications of nonthermal plasma have expanded beyond the biomedical field to include antibacterial, anti-inflammatory, wound healing, and tissue regeneration. Plasma enhances epithelial cell repair; however, the potential damage to deep tissues and vascular structures remains under investigation. RESULT: This study assessed whether liquid plasma (LP) increased nitric oxide (NO) production in human umbilical vein endothelial cells by modulating endothelial NO synthase (eNOS) phosphorylation and potential signaling pathways. First, we developed a liquid plasma product and confirmed the angiogenic effect of LP using the Matrigel plug assay. We found that the NO content increased in plasma-treated water. NO in plasma-treated water promoted cell migration and angiogenesis in scratch and tube formation assays via vascular endothelial growth factor mRNA expression. In addition to endothelial cell proliferation and migration, LP influenced extracellular matrix metabolism and matrix metalloproteinase activity. These effects were abolished by treatment with NG-L-monomethyl arginine, a specific inhibitor of NO synthase. Furthermore, we investigated the signaling pathways mediating the phosphorylation and activation of eNOS in LP-treated cells and the role of LKB1-adenosine monophosphate-activated protein kinase in signaling. Downregulation of adenosine monophosphate-activated protein kinase by siRNA partially inhibited LP-induced eNOS phosphorylation, angiogenesis, and migration. CONCLUSION: The present study suggests that LP treatment may be a novel strategy for promoting angiogenesis in vascular damage. Video Abstract.

The Impact of LY487379 or CDPPB on eNOS Expression in the Mouse Brain and the Effect of Joint Administration of Compounds with NO• Releasers on MK-801- or Scopolamine-Driven Cognitive Dysfunction in Mice.

The role of endothelial nitric oxide synthase (eNOS) in the regulation of a variety of biological processes is well established, and its dysfunction contributes to brain pathologies, including schizophrenia or Alzheimer's disease (AD). Positive allosteric modulators (PAMs) of metabotropic glutamate (mGlu) receptors were shown to be effective procognitive compounds, but little is known about their impact on eNOS expression and stability. Here, we investigated the influence of the acute and chronic administration of LY487379 or CDPPB (mGlu2 and mGlu5 PAMs), on eNOS expression in the mouse brain and the effect of the joint administration of the ligands with nitric oxide (NO) releasers, spermineNONOate or DETANONOate, in different combinations of doses, on MK-801- or scopolamine-induced amnesia in the novel object recognition (NOR) test. Our results indicate that both compounds provoked eNOS monomer formation, and CDPPB at a dose of 5 mg/kg exaggerated the effect of MK-801 or scopolamine. The coadministration of spermineNONOate or DETANONOate enhanced the antiamnesic effect of CDPPB or LY487379. The best activity was observed for ineffective or moderate dose combinations. The results indicate that treatment with mGluR2 and mGluR5 PAMs may be burdened with the risk of promoting eNOS uncoupling through the induction of dimer dissociation. Administration of the lowest possible doses of the compounds with NO• donors, which themselves have procognitive efficacy, may be proposed for the treatment of schizophrenia or AD.

Nitric oxide releasing novel amino acid-derived polymeric nanotherapeutic with anti-inflammatory properties for rapid wound tissue regeneration.

Endogenous gasotransmitter nitric oxide (NO) is a central signalling molecule that modulates wound healing by maintaining homeostasis, collagen formation, wound contraction, anti-microbial action and accelerating tissue regeneration. The optimum delivery of NO using nanoparticles (NPs) is clinically challenging; hence, it is drawing significant attention in wound healing. Herein, a novel polymeric nanoplatform loaded with sodium nitroprusside (SP) NPs was prepared and used for wound healing to obtain the sustained release of NO in therapeutic quantities. SP NPs-induced excellent proliferation (∼300%) of mouse fibroblast (L929) cells was observed. With an increase in the SP NPs dose at 200 µg mL-1 concentration, a 200% upsurge in proliferation was observed along with enhanced migration, and only 17.09 h were required to fill the 50% gap compared to 37.85 h required by the control group. Further, SP NPs showed an insignificant impact on the coagulation cascade, revealing safe wound-healing treatment when tested in isolated rat RBCs. Additionally, SP NPs exhibited excellent angiogenic activity at a 10 µg mL-1 dose. Moreover, the formulated SP nanoformulation is non-irritant, non-toxic, and does not produce any skin sensitivity reaction on the rat's skin. Further, an in vivo wound healing study revealed that within 11 days of treatment with SP nanoformulation, 99.2 ± 1.0% of the wound was closed, while in the control group, only 45.5 ± 3.8% was repaired. These results indicate that owing to sustained NO release, the SP NP and SP nanoformulations are paramount with enormous clinical potential for the regeneration of wound tissues.

Nitric oxide reduces cadmium uptake in wheat (Triticum aestivum L.) by modulating growth, mineral uptake, yield attributes, and antioxidant profile.

Wheat (Triticum aestivum L.) is among the plants that are at risk from cadmium (Cd), a hazardous heavy metal that can be fatal due to its rapid absorption and high mobility. Being taken up from the soil and moving to the shoots and roots of edible plants, it enters the food chain and poses a health concern to people worldwide. A strategically important cereal crop, wheat has a demonstrated role in human health systems, particularly in poor nations. In this study, we describe the effects of nitric oxide (NO) on the growth, nutrition, and physiological functions of commercially cultivated wheat cvs. Galaxy 2013 and Akbar 2019 under Cd stress. Four-week-old plants were subjected to Cd (0.5 mM) stress, and after 2 weeks of Cd toxicity, foliar application of nitric oxide (100 and 150 µM) was carried out. As evident from excessive antioxidant production, Cd toxicity increased reactive oxygen species (ROS) level like H2O2 and significantly (p ≤ 0.001) decreased nutrient acquisition, growth, and yield attributes of plants under experiment. The severity of the effect varied between cultivars under investigation. A minimum accumulation of MDA (44%) and H2O2 (55%) was found in the cv. Akbar 2019 under Cd stress, whilst cv. Galaxy 2013 showed the highest accumulation of the oxidative stress indicators malondialdehyde content (MDA) (48%) and H2O2 (60%). Reduced and oxidized glutathione contents were also increased under Cd-induced toxicity. The application of NO resulted in a significant improvement of 22, 25, 25, and 30% in shoot fresh weight, root fresh weight, shoot dry weight, and root dry weight, respectively. Additionally, there was an increased uptake of Ca+2 (16%), K+1 (5%), chlorophyll a (46%), b (32%), a/b ratio (41%), and carotenoid (28%). When compared with Cd-stressed plants, yield parameters like 100 grain weight, number of tillers plant-1, and grain yield plant-1 improved by 14, 17, and 33%, respectively, under NO application. We concluded from the results of this study that NO treatments increased plant development by lowering oxidative stress and limiting Cd uptake. It is inferred from the results of this study that wheat production with reduced heavy metal uptake may be facilitated using NO due to its cytoprotective properties and its interaction with ROS.

Nitric Oxide-Releasing Porous Coating with Antibacterial Activity and Blood Compatibility.

Nitric oxide (NO)-releasing coating is promising to enhance the biocompatibility of medical devices. In this study, polyurethane (PU) and S-nitrosated keratin (KSNO) were dissolved with dimethyl sulfoxide (DMSO) and tetrahydrofuran (THF) to prepare a coating solution. This solution is facile to form a porous coating on various substrates based on solvent-evaporation-induced phase separation (SEIPS). The coating could continuously release NO up to 200 h in the presence of ascorbic acid (Asc). In addition, the coating could accelerate endothelialization by promoting the viability of human umbilical vein endothelial cells (HUVECs) while inhibiting the proliferation of human umbilical artery smooth muscle cells (HUASMCs). Furthermore, the coating had good antibacterial activity and blood compatibility. Taken together, this universal coating provides wider potential applications in the field of cardiovascular implants.

Endogenous Nitric Oxide Can Enhance Oxidative Stress Caused by Air Pollutants and Explain Higher Susceptibility of Individuals with Inflammatory Disorders.

Air pollution causes morbidity and excess mortality. In the epithelial lining fluid of the respiratory tract, air pollutants trigger a chemical reaction sequence that causes the formation of noxious hydroxyl radicals that drive oxidative stress. For hitherto unknown reasons, individuals with pre-existing inflammatory disorders are particularly susceptible to air pollution. Through detailed multiphase chemical kinetic analysis, we show that the commonly elevated concentrations of endogenous nitric oxide in diseased individuals can increase the production of hydroxyl radicals via peroxynitrite formation. Our findings offer a molecular rationale of how adverse health effects and oxidative stress caused by air pollutants may be exacerbated by inflammatory disorders.

Biocatalytic nitric oxide generating hydrogels with enhanced anti-inflammatory, cell migration, and angiogenic capabilities for wound healing applications.

Although wound healing is a normal physiological process in the human body, it is often impaired by bacterial infections, ischemia, hypoxia, and excess inflammation, which can lead to chronic and non-healing wounds. Recently, injectable hydrogels with controlled nitric oxide (NO) release behaviour have become potential wound healing therapeutic agents due to their excellent biochemical, mechanical, and biological properties. Here, we proposed novel multifunctional NO-releasing hydrogels that could regulate various wound healing processes, including hemostasis, inflammation, cell proliferation and angiogenesis. By incorporating the copper nanoparticles (NPs) in the network of dual enzymatically crosslinked gelatin hydrogels (GH/Cu), NO was in situ produced via the Cu-catalyzed decomposition of endogenous RSNOs available in the blood, thus resolving the intrinsic shortcomings of NO therapies, such as the short storage and release time, as well as the burst and uncontrollable release modes. We demonstrated that the NO-releasing gelatin hydrogels enhanced the proliferation and migration of endothelial cells, while promoting the M2 (anti-inflammatory) polarization of the macrophage. Furthermore, the effects of NO release on angiogenesis were evaluated using an in vitro tube formation assay and in ovo chicken chorioallantoic membrane (CAM) assay, which revealed that GH/Cu hydrogels could significantly facilitate neovascularization, consistent with the in vivo results. Therefore, we suggested that these hydrogel systems would significantly enhance the wound healing process through the synergistic effects of the hydrogels and NO, and hence could be used as advanced wound dressing materials.

Arginine-assembly as NO nano-donor prevents the negative feedback of macrophage repolarization by mitochondrial dysfunction for cancer immunotherapy.

Repolarizing the tumor-associated macrophages (TAMs) towards the antitumoral M1-like phenotype has been a promising approach for cancer immunotherapy. However, the anti-cancer immune response is severely limited mainly by the repolarized M1-like macrophages belatedly returning to the M2-like phenotype (i.e., negative feedback). Inspired by nitric oxide (NO) effectively preventing repolarization of inflammatory macrophages in inflammatory diseases, herein, we develop an arginine assembly, as NO nano-donor for NO generation to prevent the negative feedback of the macrophage repolarization. The strategy is to first apply reversible tagging of hydrophobic terephthalaldehyde to create an arginine nano-assembly, and then load a toll-like receptor 7/8 agonist resiquimod (R848) (R848@Arg). Through this strategy, a high loading efficiency of 40 % for the arginine and repolarization characteristics for TAMs can be achieved. Upon the macrophage repolarization by R848, NO can be intracellularly generated from the released arginine by the upregulated inducible nitric oxide synthase. Mechanistically, NO effectively prevented the negative feedback of the repolarized macrophage by mitochondrial dysfunction via blocking oxidative phosphorylation. Notably, R848@Arg significantly increased the tumor inhibition ratio by 3.13-fold as compared to the free R848 by maintaining the M1-like phenotype infiltrating into tumor. The Arg-assembly as NO nano-donor provides a promising method for effective repolarization of macrophages.

Effects of elevated levels of intracellular nitric oxide on Pseudomonas aeruginosa biofilm in chronic skin wound and slow-killing infection models.

Nitric oxide (NO), produced through the denitrification pathway, regulates biofilm dynamics through the quorum sensing system in Pseudomonas aeruginosa. NO stimulates P. aeruginosa biofilm dispersal by enhancing phosphodiesterase activity to decrease cyclic di-GMP levels. In a chronic skin wound model containing a mature biofilm, the gene expression of nirS, encoding nitrite reductase to produce NO, was low, leading to reduced intracellular NO levels. Although low-dose NO induces biofilm dispersion, it is unknown whether it influences the formation of P. aeruginosa biofilms in chronic skin wounds. In this study, a P. aeruginosa PAO1 strain with overexpressed nirS was established to investigate NO effects on P. aeruginosa biofilm formation in an ex vivo chronic skin wound model and unravel the underlying molecular mechanisms. Elevated intracellular NO levels altered the biofilm structure in the wound model by inhibiting the expression of quorum sensing-related genes, which was different from an in vitro model. In Caenorhabditis elegans as a slow-killing infection model, elevated intracellular NO levels increased worms' lifespan by 18%. Worms that fed on the nirS-overexpressed PAO1 strain for 4 h had complete tissue, whereas worms that fed on empty plasmid-containing PAO1 had biofilms on their body, causing severe damage to the head and tail. Thus, elevated intracellular NO levels can inhibit P. aeruginosa biofilm growth in chronic skin wounds and reduce pathogenicity to the host. Targeting NO is a potential approach to control biofilm growth in chronic skin wounds wherein P. aeruginosa biofilms are a persistent problem.

Nitric oxide and AMF-mediated regulation of soil enzymes activities, cysteine-H2S system and thiol metabolites in mitigating chromium (Cr (VI)) toxicity in pigeonpea genotypes.

Cr (VI) hampers plant growth and yield by reducing essential nutrient uptake as it competes for phosphate and sulfate transporters. Nitric oxide (NO) and mycorrhization play important roles in mitigating Cr (VI) toxicity. Present study aimed to compare the potential of AMF (Arbuscular mycorrhizal fungi)-Rhizoglomus intraradices and NO (0.25 mM) in alleviating Cr (VI) stress (0, 10 and 20 mg/kg) in two differentially tolerant pigeonpea genotypes (Pusa 2001 and AL 201). Cr (VI) toxicity reduced growth, mycorrhizal colonization, nutrient uptake, and overall productivity by inducing reactive oxygen species (ROS) generation, with AL 201 more sensitive than Pusa 2001. NO and AM enhanced activities of soil enzymes, thereby increasing nutrients availability as well as their uptake, with AM more effective than NO. Both amendments reduced oxidative stress and restricted Cr (VI) uptake by increasing the activities of antioxidant and S- assimilatory enzymes, with Pusa 2001 more responsive than AL 201. NO was relatively more efficient in regulating cysteine-H2S system by increasing the activities of biosynthetic enzymes (ATP-sulfurylase (ATPS), O-acetylserine thiol lyase (OASTL), D-cysteine desulfhydrase (DCD) and L-cysteine desulfhydrase (LCD), while AM significantly increased glutathione reductase (GR), γ-glutamylcysteine synthetase (γ-ECS) enzymes activities and resultant glutathione (GSH), phytochelatins (PCs), and non-protein thiols (NP-SH) synthesis. Moreover, co-application of NO and AM proved to be highly beneficial in negating the toxic effects of Cr (VI) due to functional complementarity between them. Study suggested the combined use of NO and AM as a useful strategy in re-establishing pigeonpea plants growing in Cr (VI)-stressed environments.