Chitosan-chelated carbon dots-based nanozyme of extreme stability with super peroxidase activity and antibacterial ability for wound healing.

Bacterial infection often leads to failed wound healing, causing one-third of death cases globally. However, antibacterial nanomaterials and natural enzymes face limitations including low antibacterial efficiency, lack of catalytic performance, low safety, and instability. Therefore, a new Fe/N-doped chitosan-chelated carbon dot-based nanozyme CS@Fe-N CDs was developed, which showed multiple advantages such as highly efficient antibacterial activity, excellent peroxidase-like activity, high stability, and high biocompatibility, shortening the wound healing time. The ultra-small (6.14 ± 3.38 nm) CS@Fe-N CDs nanozyme accelerated the H2O2 to ·OH conversion, exhibiting excellent antibacterial performance against Staphylococcus aureus. The antibacterial activity was increased by over 2000-fold after catalysis. The CS@Fe-N CDs nanozyme also displayed outstanding peroxidase activity (Vmax/Km = 1.77 × 10-6/s), 8.8-fold higher than horseradish peroxidase. Additionally, the CS@Fe-N CDs nanozyme exhibited high stability at broad pH values (pH 1-12) and temperature ranges (20-90 °C). In vitro evaluation of cell toxicity proved that the CS@Fe-N CDs nanozyme had negligible cytotoxicity. In vivo, wound healing experiments demonstrated that the CS@Fe-N CDs could shorten the healing time of rat wounds by at least 4 days, and even had a better curative effect than penicillin. In conclusion, this therapeutic platform provides an effective antibacterial and biologically safe healing strategy for skin wounds.

Effects of exogenous zinc on the physiological characteristics and enzyme activities of Passiflora edulis Sims f. edulis seedlings.

Passionflower (Passiflora edulis Sims) is widely distributed in tropical and subtropical areas for edible, medicinal and skin care product processing, and the market demand is large. Zinc (Zn) is a necessary trace element for plant growth and development. In many countries, the content of Zn in soil is low and/or bioavailability is low. The exogenous application of Zn has become a common agronomic measure in agriculture. However, the effect of Zn on the physiological characteristics and enzyme activity of passionflower seedlings is not clear. In this study, pot experiments were conducted to analyse the effects of different concentrations of Zn (0, 200, 400, 800 mg kg-1) on the plant growth, photosynthetic pigments, osmotic regulators, membrane system and antioxidant enzyme system of purple passionflower (Passiflora edulis Sims f. edulis) seedlings, and Pearson correlation and principal component analyses were performed. The results showed that (1) the 200 mg kg-1 Zn treatment increased the contents of chlorophyll a (37.65%), chlorophyll b (41.22%), chlorophyll a+b (38.59%) and carotenoids (29.74%). The value of chlorophyll a/b changed little and had no effect on leaf growth. (2) The contents of proline (Pro) and malondialdehyde (MDA) in P. edulis Sims f. edulis seedlings treated with 400 mg kg-1 Zn increased significantly by 116.84% and 42.69%, respectively. The activities of catalase (CAT) and peroxidase (POD) increased by 16.82% and 18.70%, respectively. Superoxide dismutase (SOD), leaf area (LA), leaf perimeter (LP) and leaf width (LW) decreased significantly by 47.20%, 19.75%, 8.32% and 11.97%, respectively. (3) 800 mg kg-1 Zn significantly increased the contents of Pro (202.56%) and MDA (26.7%) and the activities of CAT (16.00%) and POD (67.00%), while the soluble sugar (SS), SOD, LA, LP and LW decreased significantly by 36.67%, 32.86%, 23.36%, 8.32% and 11.18%, respectively. (4) There was a significant positive correlation between Pro and photosynthetic pigments and between SOD and leaf growth and a significant negative correlation between POD and SS and between SOD and MDA. (5) A low concentration (200 mg kg-1) of Zn promoted the growth of P. edulis Sims f. edulis seedlings and allowed stress caused by high Zn concentrations to be tolerated. The results of this study can provide a reference for the application of Zn fertilizer to P. edulis Sims f. edulis.

Physiological responses of typical subtropical landscape shrubs to artificial light at night.

Artificial light at night is rapidly spreading and has become an important component of global change. Although numerous studies have focused on its potential ecological impacts, the physiological response mechanisms of landscape plants to artificial light at night have rarely been quantified. With common landscape shrubs in subtropical regions of China, Hydrangea paniculata, Photinia fraseri and Ligustrum japonicum, as test materials, we exa-mined the responses of antioxidant enzyme system and biomass in the light environment at night under different light quality (yellow light, white light) with different light intensities (20, 40, 60 lx) . The results showed that artificial light at night significantly increased the membrane peroxidation, stimulated plant antioxidant protection systems and raised the antioxidant enzyme activities of the three species. The effects of light quality on plant antioxidant enzymes varied across dspecies. The peroxidase (POD) and catalase (CAT) activities of H. paniculata under white light were 1.5 and 1.3 times as that under yellow light, respectively. Both enzyme activities of P. fraseri were 1.1 times as that under white light than under yellow light. The activities of two enzymes in L. japonicum under white light were 88.6% and 99.5% of those under yellow light, respectively. The antioxidant enzyme activities of the three species increased with increasing light intensity at night, whereas the contents of malondialdehyde increased rapidly and the antioxidant enzyme activities decreased when beyond a certain light intensity threshold (at 120 d, the threshold was about 40 lx). The protective enzymes that played the major role under nighttime light stress were different among the three species. For H. paniculata, POD and CAT complemented each other to resist stress-induced oxidative damage, while the main enzyme of L. japonicum was POD. The biomass of the three species increased significantly under artificial light at night. H. paniculata was the most sensitive to nighttime light stress, while L. japonicum had the strongest resistance to the stress. The deciduous shrub H. paniculata could tolerate the white night light lower than 40 lx, while the evergreen shrubs P. fraseri and L. japonicum could tolerate the yellow night light lower than 40 lx.

Effect of Exogenous Plant Growth Regulators and Rejuvenation Measures on the Endogenous Hormone and Enzyme Activity Responses of Acer mono Maxim in Cuttage Rooting.

The cuttage rooting method for Acer species is difficult to achieve a good efficacy as trees maintain good characteristics at the rejuvenation stage, thus improving the rooting of Acer species. The addition of exogenous hormones and rejuvenation can improve the rooting effect of cuttings; however, the specific regulatory mechanism is still unclear. Here, Acer mono Maxim rejuvenation and non-rejuvenation cuttings were used as test subjects, to investigate the effects of exogenous hormones on the activities of endogenous hormones and antioxidant enzymes in the rooting process of young cuttings. The results showed that exogenous growth-regulating substances significantly improved the rooting rate of A. mono. Exogenous hormones naphthylacetic acid (NAA) + indolebutyric acid (IBA) increased the initial levels of the endogenous hormones, indoleacetic acid (IAA) and abscisic acid (ABA), and the enzyme activities of peroxidase (POD) and polyphenol oxidase (PPO). Rejuvenation treatment prolonged the time of increase in ABA content and indoleacetic acid oxidase (IAAO) activity at the root primordium induction stage, while increasing trans-zeatin riboside (ZR) content and decreasing POD enzyme activity in cuttings. These results demonstrate that A. mono cuttings can achieve the purpose of improving the rooting rate by adding the exogenous hormone (NAA + IBA), which is closely related to the changes of endogenous hormone content and enzyme activity, and these changes of A. mono rejuvenation cuttings are different from non-rejuvenation cuttings.

GYY4137, a hydrogen sulfide donor, protects against endothelial dysfunction in porcine coronary arteries exposed to myeloperoxidase and hypochlorous acid.

BACKGROUND AND AIMS: Myeloperoxidase (MPO) and its principal reaction product hypochlorous acid (HOCl) are part of the innate immune response but are also associated with endothelial dysfunction, thought to involve a reduction in nitric oxide (NO) bioavailability. We aimed to investigate the effect of MPO and HOCl on vasorelaxation of coronary arteries and to assess directly the involvement of NO. In addition, we hypothesised that the slow release hydrogen sulfide (H2S) donor GYY4137 would salvage coronary artery endothelial function in the presence of MPO and HOCl. METHODS AND RESULTS: Contractility of porcine coronary artery segments was measured using isometric tension recording. Incubation with MPO (50 ng/ml) plus hydrogen peroxide (H2O2) (30 µM; substrate for MPO) impaired endothelium-dependent vasorelaxation to bradykinin in coronary arteries. HOCl (10-500 µM) also impaired endothelium-dependent relaxations. There was no effect of MPO plus H2O2, or HOCl, on endothelium-independent relaxations to 5'-N-ethylcarboxamidoadenosine and sodium nitroprusside. L-NAME (300 µM), a NO synthase inhibitor, attenuated bradykinin relaxations, leaving L-NAME-resistant relaxations to bradykinin mediated by endothelium-dependent hyperpolarization. In the presence of L-NAME, MPO plus H2O2 largely failed to impair endothelium-dependent relaxations to bradykinin. Similarly, HOCl failed to inhibit endothelium-dependent relaxations to bradykinin in the presence of L-NAME. GYY4137 (1-100 µM) protected endothelium-dependent relaxations to bradykinin from dysfunction caused by MPO plus H2O2, and HOCl, with no effect alone on bradykinin relaxation responses. The specific MPO inhibitor aminobenzoic acid hydrazide (ABAH) (1 and 10 µM) also protected against MPO plus H2O2-induced endothelial dysfunction (at 10 µM ABAH), but was less potent than GYY4137. CONCLUSIONS: MPO plus H2O2, and HOCl, impair coronary artery endothelium-dependent vasorelaxation via inhibition of NO. GYY4137 protects against endothelial dysfunction in arteries exposed to MPO plus H2O2, and HOCl. H2S donors such as GYY4137 are possible therapeutic options to control excessive MPO activity in cardiovascular diseases.

Rationale and design of ENDEAVOR: A sequential phase 2b-3 randomized clinical trial to evaluate the effect of myeloperoxidase inhibition on symptoms and exercise capacity in heart failure with preserved or mildly reduced ejection fraction.

AIMS: Mitiperstat (formerly AZD4831) is a novel selective myeloperoxidase inhibitor. Currently, no effective therapies target comorbidity-induced systemic inflammation, which may be a key mechanism underlying heart failure with preserved or mildly reduced ejection fraction (HFpEF/HFmrEF). Circulating neutrophils secrete myeloperoxidase, causing oxidative stress, microvascular endothelial dysfunction, interstitial fibrosis, cardiomyocyte remodelling and diastolic dysfunction. Mitiperstat may therefore improve function of the heart and other organs, and ameliorate heart failure symptoms and exercise intolerance. ENDEAVOR is a combined, seamless phase 2b-3 study of the efficacy and safety of mitiperstat in patients with HFpEF/HFmrEF. METHODS: In phase 2b, approximately 660 patients with heart failure and ejection fraction >40% are being randomized 1:1:1 to mitiperstat 2.5 mg, 5 mg or placebo for 48 weeks. Eligible patients have baseline 6-min walk distance (6MWD) of 30-400 m with a <50 m difference between screening and randomization and Kansas City Cardiomyopathy Questionnaire total symptom score (KCCQ-TSS) ≤90 points at screening and randomization. The dual primary endpoints are change from baseline to week 16 in 6MWD and KCCQ-TSS. The sample size provides 85% power to detect placebo-adjusted improvements of 21 m in 6MWD and 6.0 points in KCCQ-TSS at overall two-sided alpha of 0.05. Safety is monitored throughout treatment, with a focus on maculopapular rash. In phase 3 of ENDEAVOR, approximately 820 patients will be randomized 1:1 to mitiperstat or placebo. CONCLUSION: ENDEAVOR is the first phase 2b-3 study to evaluate whether myeloperoxidase inhibition can improve symptoms and exercise capacity in patients with HFpEF/HFmrEF.

Cerebrolysin Amelioration of Spinal Cord Ischemia/ Reperfusion Injury in Rabbit Model.

AIM: To investigate the effects of cerebrolysin on inflammation, oxidative stress, apoptosis, and neurologic recovery in the setting of an experimental rabbit model of spinal cord ischemia/reperfusion injury (SCIRI). MATERIAL AND METHODS: Rabbits were randomly divided into five groups: control, ischemia, vehicle, methylprednisolone (30 mg/kg), and cerebrolysin (5 ml/kg) group. The rabbits in the control group underwent only laparotomy; the other groups underwent spinal cord ischemia and reperfusion injury for 20 minutes. Neurologic examination after 24 hours was based on the Modified Tarlov scale. Myeloperoxidase activities, catalase and malondialdehyde levels, and caspase-3 concentrations were determined in serum and tissue samples. Serum xanthine oxidase levels were studied and histopathological and ultrastructural changes were examined. RESULTS: After SCIRI, serum and tissue myeloperoxidase activities, malondialdehyde levels, caspase-3 concentrations, and serum xanthine oxidase activities were increased (p < 0.01?0.001). Catalase levels were significantly diminished (p < 0.001). Cerebrolysin treatment correlated with reduced myeloperoxidase and xanthine oxidase activities, malondialdehyde levels and caspase-3 concentrations; and with increased catalase levels (p < 0.001, for all). The cerebrolysin group showed improved histopathological, ultrastructural, and neurological outcomes. CONCLUSION: For the first time in the literature, the current study reports anti-inflammatory, antioxidant, antiapoptotic, and neuroprotective effects of cerebrolysin in a SCIRI rabbit model.

Oxidative stress triggers hyperdynamic circulation via central neural activation in portal hypertensive rats.

BACKGROUND: Hyperdynamic circulation in portal hypertension (PHT) depends on central neural activation. However, the initiating mechanism that signals PHT to the central neural cardiovascular-regulatory centers remains unclear. We aimed to test the hypothesis that oxidative stress in the gut initiates the signal that activates central cardiovascular nuclei in portal hypertensive rats. METHODS: Two groups of rats were used. One had portal hypertension produced by partial portal vein ligation, while controls underwent sham operation. Hemodynamics including portal pressure, cardiac output, mean arterial pressure (MAP) and peripheral vascular resistance were measured. Activation of central cardiovascular nuclei was determined by immunohistochemical Fos expression in the paraventricular nucleus (PVN) of the hypothalamus. Myeloperoxidase activity, an oxidative stress marker, was measured in the jejunum. Hydrogen peroxide, the antioxidant N-acetyl-cysteine (NAC) or saline controls were administered for 12-14 days by gavage or osmotic minipumps placed in the peritoneal cavity. RESULTS: Compared with controls, PHT rats showed increased cardiac output (54.2 ± 9.5 vs 33.6 ± 2.4 ml/min/100 g BW, p < 0.01), decreased MAP (96.2 ± 6.4 mmHg vs 103.2 ± 7.8, p < 0.01) and systemic vascular resistance (1.84 ± 0.28 vs 3.14 ± 0.19 mmHg/min/ml/100 g BW, p < 0.01). PHT rats had increased jejunal myeloperoxidase and PVN Fos expression. NAC treatment eliminated the hyperdynamic circulation, decreased jejunal myeloperoxidase and PVN Fos expression in PHT rats, but had no effect on sham controls. H2O2 significantly increased PVN Fos expression and decreased MAP. CONCLUSION: These results indicate that in PHT, mesenteric oxidative stress is the initial signal that activates chemoreceptors and triggers hyperdynamic circulation by central neural cardiovascular-regulatory centers.

Superoxide: The enigmatic chemical chameleon in neutrophil biology.

The burst of superoxide produced when neutrophils phagocytose bacteria is the defining biochemical feature of these abundant immune cells. But 50 years since this discovery, the vital role superoxide plays in host defense has yet to be defined. Superoxide is neither bactericidal nor is it just a source of hydrogen peroxide. This simple free radical does, however, have remarkable chemical dexterity. Depending on its environment and reaction partners, superoxide can act as an oxidant, a reductant, a nucleophile, or an enzyme substrate. We outline the evidence that inside phagosomes where neutrophils trap, kill, and digest bacteria, superoxide will react preferentially with the enzyme myeloperoxidase, not the bacterium. By acting as a cofactor, superoxide will sustain hypochlorous acid production by myeloperoxidase. As a substrate, superoxide may give rise to other forms of reactive oxygen. We contend that these interactions hold the key to understanding the precise role superoxide plays in neutrophil biology. State-of-the-art techniques in mass spectrometry, oxidant-specific fluorescent probes, and microscopy focused on individual phagosomes are needed to identify bactericidal mechanisms driven by superoxide. This work will undoubtably lead to fascinating discoveries in host defense and give a richer understanding of superoxide's varied biology.

Protective effect of indole-3-carbinol on testis of a high fat diet induced obesity.

We investigated the effects of obesity caused by a high fat diet (HFD) on rat testes and evaluated the possible protective effects of indole-3-carbinol (IND). We used 24 8-10-week-old 200 g male rats randomly assigned to 4 groups: non-obese control (NC), obese control (OC), non-obese IND group (NI), obese + IND group (OI). Testis samples were examined using stereological, immunohistochemical, biochemical and histological methods. The number of spermatogenic cells, Leydig cells, mean volume of testes and seminiferous tubules was significantly decreased in the OC group compared to the NC group, but these values were increased significantly in the OI group compared to the OC group. We found a significant increase in catalase and myeloperoxidase activities in the OC group compared to the NC group. In the OI group, catalase and myeloperoxidase levels were decreased compared to the OC group. TUNEL-positive cells also were increased in the OC group compared to the NC group (p < 0.05), but these were fewer in the OI group than the OC group. We found marked morphological changes in testicular tissues between the NC and OC groups, as well as between the OI and OC groups. We found that HFD induced obesity was detrimental to rat testes and that administration of IND ameliorated testicular changes caused by obesity.

Quercetin Protected from Aluminum Phosphide-induced Acute and Subacute Cardio- and Hepatotoxicity in Rats.

BACKGROUND: Aluminum phosphide (ALP) intoxication either accidentally or intentionally, is one of the major health concerns in developing countries. Its poisoning causes severe damage to organs including the heart and liver. OBJECTIVES: This study aimed to investigate the hepato- and cardioprotective effects of quercetin (QCN) on the acute/subacute toxicity of ALP in rodent models. METHODS: Acute (single dose, 12.5 mg/kg, orally) and subacute (2 mg/kg, orally and 7 days) intoxication of ALP were induced in rats and the protective effects of QCN on altered hepatic/cardiac functional enzyme concentrations, myeloperoxidase activity, oxidative stress biomarkers, and histopathological changes were studied at three doses of 10, 50 and 100 mg/kg BW. To record any heart abnormality, an electrocardiogram (ECG) was recorded 3 h after the last treatment. RESULTS: Quercetin reduced the ALP-increased hepatic and cardiac functional enzyme concentrations and myeloperoxidase activity. Moreover, QCN improved remarkably the ALP-induced ECG abnormalities (T inversion, bigeminy in R waves) and arrhythmias. QCN attenuated significantly (p < 0.05) the ALP-induced oxidative/ nitrosative stress and histopathological injuries in the liver and heart. CONCLUSION: Our results suggest that QCN is able to protect the ALP-induced cardiac and hepatic injuries in both acute and subacute models and its effects attribute to its antioxidant and anti-inflammatory properties.

Effects of inorganic arsenic species on the antioxidant enzyme system of the Amazon Sword Plant (Echinodorus amazonicus Rataj).

This study aims to examine the effects of Arsenite (As+3) and Arsenate (As+5) on the aquatic macrophyte Amazon Sword Plant (Echinodorus amazonicus Rataj). To this aim, different concentrations of As+3 and As+5 (0, 6, 18 and 54 µM) were analyzed. At the end of the trail, photosynthetic pigment contents, total protein amounts, the enzymatic antioxidants superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) activities and the amount of malondialdehyde (MDA) in the leaf samples of E. amazonicus were investigated. The antioxidant enzyme activities increased at low concentrations (32.13% for SOD, 185% for CAT and 201.5% for POX in the groups of 6 µM As+5), but decreased at high concentrations (64.98% for SOD, 21.64% for CAT and 21.29% for POX in the groups of 54 µM As+3). MDA increased in all the treatment groups. The highest MDA contents were observed as 96% for 54 µM As+3 and 71.50% for 54 µM As+5. Photosynthetic pigment contents and the amount of protein were decreased with higher concentrations. The most significant decreases in protein content were 65% for 54 µM As+3 and 34.9% for 54 µM As+5. As a result, the toxicity of As+3 was higher and the toxic effect increased at higher concentrations.

Ulexite modulates the neurotoxicological outcomes of acetylferrocene-exposed rainbow trout.

In this study, the neuroprotective action potential by ulexite (UX) (18.75 mg/L) against acetylferrocene (AFC) (3.82 mg/L) induced neurotoxicity was aimed to investigate in brain tissues of Oncorhynchus mykiss. For this purpose, the effects on neurotoxicity markers, proinflammatory cytokines, antioxidant immune system, DNA, and apoptosis mechanisms were assessed on brain tissues in the 48-96  h of the 96- trial period. In this research, it was determined that brain-derived nerve cell growth factor (BDNF) level and acetylcholinesterase (AChE) activity were inhibited in the brain tissue compared to the control group by AFC. In addition, inhibition in glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH) values (which are antioxidant system biomarkers), and inductions in malondialdehyde (MDA) and myeloperoxidase (MPO) amounts (which are indicators of lipid peroxidation) were determined (p < 0.05) after exposure to AFC. And, while tumor necrosis factor-α (TNF-α) and IL-6 levels were increased in the AFC-exposed group, Nrf-2 levels were found to be remarkably decreased. Upregulation was also detected in 8-hydroxydeoxyguanosine (8-OHdG) and caspase-3 levels, which are related to DNA damage and apoptosis mechanism. On the contrary, UX (single/with AFC) suppressed the AChE and BDNF inhibition by AFC. Moreover, UX mitigated AFC-induced oxidative, inflammatory, and DNA damage and attenuated AFC-mediated neurotoxicity via activating Nrf2 signaling in fish. Collectively, our findings revealed that UX supplementation might exert beneficial effects and may be considered as a natural and promising neuroprotective agent against AFC-induced toxicity.

Hesperetin-Based Hydrogels Protect the Skin against UV Radiation-Induced Damage.

UV radiation can cause damages, such as erythema, skin photoaging, and carcinogenesis. The adoption of protective measures against sun exposure is essential to prevent these damages, and the interest in using natural substances as an alternative for photoprotection is growing. Thus, hesperetin with antioxidant, anti-inflammatory, and anticancer properties is a promising substance to be used with photochemopreventive action and to protect the skin from damage induced by UV radiation. Therefore, the present study aimed to develop a topical formulation based on AAMVPC gel containing hesperetin and evaluate its photoprotective effect on the skin of rats exposed to UVA-UVB radiation. The animals were submitted to the irradiation protocol UVA-UVB, and at the end, erythema, lipid peroxidation, and activity of the antioxidant enzyme catalase and superoxide dismutase were evaluated. Additionally, it evaluated the activity of myeloperoxidase and histological changes. The formulation presented a rheological and spreadability profile suitable for cutaneous application. In vivo results demonstrated that the topical formulation of AAMVPC gel containing hesperetin at a concentration of 10% protected the skin from damage induced by UVA-UVB radiation, with the absence of erythema, lipid lipoperoxidation, and inflammation (low myeloperoxidase activity), and increased catalase and superoxide dismutase activities. The morphology and architecture of the dermo-epidermal tissue of these animals were like those observed under normal conditions (non-irradiated animals). Thus, the results showed that hesperetin was able to protect the animals' skin against UV radiation-induced skin damage and the protection mechanisms may be related to the antioxidant and anti-inflammatory properties of this natural product.

5-Aminolevulinic acid has the potential to prevent bladder dysfunction in cyclophosphamide-induced hemorrhagic cystitis.

OBJECTIVES: To investigate the effects of pretreatment with 5-aminolevulinic acid hydrochloride combined with sodium ferrous citrate on bladder dysfunction in cyclophosphamide-induced hemorrhagic cystitis in rats. METHODS: Male Wistar rats (340-460 g) were pretreated with vehicle or with 5-aminolevulinic acid hydrochloride combined with sodium ferrous citrate (100/157 or 300/471 mg/kg/day, po) once daily for 7 days before cystometry. Saline or cyclophosphamide (150 mg/kg, ip) was administered 2 days before cystometry. Cystometry was performed under urethane anesthesia (0.8 g/kg, ip) via a catheter inserted into the bladder. After cystometry, bladder tissues were collected to perform hematoxylin and eosin staining for pathological evaluation (neutrophil infiltration, edema, and bleeding scores), and for enzyme-linked immunosorbent assay and real-time polymerase chain reaction for investigating tissue levels of myeloperoxidase, and mRNA levels of haem oxygenase-1 as a cytoprotective molecule. RESULTS: Compared to controls, cyclophosphamide induced a shorter intercontraction interval, lower bladder compliance, increased number of non-voiding contractions, and increased pathological scores and myeloperoxidase expression in the bladder. Pretreatment with 5-aminolevulinic acid hydrochloride combined with sodium ferrous citrate (300/471 mg/kg/day) significantly improved cyclophosphamide-induced intercontraction interval shortening and increases in number of non-voiding contractions and neutrophil infiltration/bleeding scores and enhanced haem oxygenase-1 expression in the bladder. In addition, cyclophosphamide-induced decreases in bladder compliance and increases in myeloperoxidase were not detected with 5-aminolevulinic acid hydrochloride combined with sodium ferrous citrate pretreatment. CONCLUSIONS: Pretreatment with 5-aminolevulinic acid expects protective effects on bladder dysfunction in cyclophosphamide-induced hemorrhagic cystitis by improving inflammatory changes in bladder tissues perhaps via up-regulation of haem oxygenase-1.

POD Nanozyme optimized by charge separation engineering for light/pH activated bacteria catalytic/photodynamic therapy.

The current feasibility of nanocatalysts in clinical anti-infection therapy, especially for drug-resistant bacteria infection is extremely restrained because of the insufficient reactive oxygen generation. Herein, a novel Ag/Bi2MoO6 (Ag/BMO) nanozyme optimized by charge separation engineering with photoactivated sustainable peroxidase-mimicking activities and NIR-II photodynamic performance was synthesized by solvothermal reaction and photoreduction. The Ag/BMO nanozyme held satisfactory bactericidal performance against methicillin-resistant Staphylococcus aureus (MRSA) (~99.9%). The excellent antibacterial performance of Ag/BMO NPs was ascribed to the corporation of peroxidase-like activity, NIR-II photodynamic behavior, and acidity-enhanced release of Ag+. As revealed by theoretical calculations, the introduction of Ag to BMO made it easier to separate photo-triggered electron-hole pairs for ROS production. And the conduction and valence band potentials of Ag/BMO NPs were favorable for the reduction of O2 to ·O2-. Under 1064 nm laser irradiation, the electron transfer to BMO was beneficial to the reversible change of Mo5+/Mo6+, further improving the peroxidase-like catalytic activity and NIR-II photodynamic performance based on the Russell mechanism. In vivo, the Ag/BMO NPs exhibited promising therapeutic effects towards MRSA-infected wounds. This study enriches the nanozyme research and proves that nanozymes can be rationally optimized by charge separation engineering strategy.

Myeloperoxidase-induced fibrinogen unfolding and clotting.

Due to its unique properties and high biomedical relevance fibrinogen is a promising protein for the development of various matrixes and scaffolds for biotechnological applications. Fibrinogen molecules may form extensive clots either upon specific cleavage by thrombin or in thrombin-free environment, for example, in the presence of different salts. Here, we report the novel type of non-conventional fibrinogen clot formation, which is mediated by myeloperoxidase and takes place even at low fibrinogen concentrations (<0.1 mg/ml). We have revealed fibrillar nature of myeloperoxidase-mediated fibrinogen clots, which differ morphologically from fibrin clots. We have shown that fibrinogen clotting is mediated by direct interaction of myeloperoxidase molecules with the outer globular regions of fibrinogen molecules followed by fibrinogen unfolding from its natural trinodular to a fibrillar structure. We have demonstrated a major role of the Debye screening effect in regulating of myeloperoxidase-induced fibrinogen clotting, which is facilitated by small ionic strength. While fibrinogen in an aqueous solution with myeloperoxidase undergoes changes, the enzymatic activity of myeloperoxidase is not inhibited in excess of fibrinogen. The obtained results open new insights into fibrinogen clotting, give new possibilities for the development of fibrinogen-based functional biomaterials, and provide the novel concepts of protein unfolding.

Superoxide Radical-Mediated Self-Synthesized Au/MoO3-x Hybrids with Enhanced Peroxidase-like Activity and Photothermal Effect for Anti-MRSA Therapy.

A rapid increase in methicillin-resistant Staphylococcus aureus (MRSA) induced infection has been noticed in recent years and the biofilm formed by MRSA further delays wound healing, causing a high mortality rate. Hence, a safe and effective superoxide radical (O2•-) mediated self-synthesis strategy is developed to prepare Au-doped MoO3-x (Au/MoO3-x) plasmonic-semiconductor hybrid for the elimination of MRSA mediated wound infection. The synthesis mechanism of Au NPs is systematically investigated, proving that O2•- plays a key role in reduction of HAuCl4 into Au NPs in the presence of H2O and O2. Au-doped MoO3-x exhibits the improved photothermal conversion efficiency (∼52.40%) compared with MoO3-x (∼41.11%). Moreover, the peroxidase (POD)-like activity of Au/MoO3-x hybrid is higher than that of MoO3-x NPs, resulting in increased yield of highly toxic ·OH. In combination with the enhanced photothermal and POD-like properties, Au/MoO3-x hybrid achieves efficient elimination of MRSA bacteria with eradication ratio of ∼99.76%. Additionally, the as-prepared Au/MoO3-x NPs exhibit excellent biosafety, which is verified via in vitro and in vivo experiments. This study provides the basis for exploring MoO3-x-based hybrids via a green O2•--mediated self-synthesis approach.

Recombinant Myeloperoxidase as a New Class of Antimicrobial Agents.

Heme-containing peroxidases are widely distributed in the animal and plant kingdoms and play an important role in host defense by generating potent oxidants. Myeloperoxidase (MPO), the prototype of heme-containing peroxidases, exists in neutrophils and monocytes. MPO has a broad spectrum of microbial killing. The difficulty of producing MPO at a large scale hinders its study and utilization. This study aimed to overexpress recombinant human MPO and characterize its microbicidal activities in vitro and in vivo. A human HEK293 cell line stably expressing recombinant MPO (rMPO) was established as a component of this study. rMPO was overexpressed and purified for studies on its biochemical and enzymatic properties, as well as its microbicidal activities. In this study, rMPO was secreted into culture medium as a monomer. rMPO revealed enzymatic activity similar to that of native MPO. rMPO, like native MPO, was capable of killing a broad spectrum of microorganisms, including Gram-negative and -positive bacteria and fungi, at low nM levels. Interestingly, rMPO could kill antibiotic-resistant bacteria, making it very useful for treatment of nosocomial infections and mixed infections. The administration of rMPO significantly reduced the morbidity and mortality of murine lung infections induced by Pseudomonas aeruginosa or methicillin-resistant Staphylococcus aureus. In animal safety tests, the administration of 100 nM rMPO via tail vein did not result in any sign of toxic effects. Taken together, the data suggest that rMPO purified from a stably expressing human cell line is a new class of antimicrobial agents with the ability to kill a broad spectrum of pathogens, including bacteria and fungi with or without drug resistance. IMPORTANCE Over the past 2 decades, more than 20 new infectious diseases have emerged. Unfortunately, novel antimicrobial therapeutics are discovered at much lower rates. Infections caused by resistant microorganisms often fail to respond to conventional treatment, resulting in prolonged illness, greater risk of death, and high health care costs. Currently, this is best seen with the lack of a cure for coronavirus disease 2019 (COVID-19). To combat such untreatable microorganisms, there is an urgent need to discover new classes of antimicrobial agents. Myeloperoxidase (MPO) plays an important role in host defense. The difficulty of producing MPO on a large scale hinders its study and utilization. We have produced recombinant MPO at a large scale and have characterized its antimicrobial activities. Most importantly, recombinant MPO significantly reduced the morbidity and mortality of murine pneumonia induced by Pseudomonas aeruginosa or methicillin-resistant Staphylococcus aureus. Our data suggest that recombinant MPO from human cells is a new class of antimicrobials with a broad spectrum of activity.

Rupatadine protects the intestinal mucosa from injury by 5-flurouracil via modulation of inflammation, apoptosis and intestinal permeability.

Fluorouracil (5-FU) is a widely used chemotherapeutic agent in various malignant tumors. However, intestinal toxicity is considered the irritant unavoidable adverse effect during the course therapy. The aim of the current study was to screen the effect of a new selective histamine receptor 1 blocker and platelet-activating factor (PAF) blocker on 5-FU induced intestinal toxicity. Five groups (6 rats each) of adult male rats (Wistar) were arranged as follows: (1) control group that was treated with carboxymethylcellulose, (2) a group that received rupatadine (higher dose) only, (3) a group that received 5-FU and (4) and (5) groups that received 5-FU plus lower or higher dose rupatadine, respectively. At end of the experiment, we determined intestinal malondialdehyde (MDA), glutathione reduced (GSH), nitric oxide (NO), tumor necrosis factor (TNF-α), interleukin 1ß, 6, 10 (IL-1ß, IL-6, IL-10), PAF, histamine, myeloperoxidase, cysteine-aspartic acid protease-3 (caspase-3), and nuclear factor kappa B (NF-κB) as well as the histological analysis. 5-FU injection caused marked elevation of MDA, NO, TNF-α, IL-1ß, IL-6, PAF, histamine, myeloperoxidase, caspase-3, and NF-κB expressions. The intoxicated animals showed deficient GSH and IL-10 along with significant loss of villi, disorganized crypts, and inflammatory cell infiltration. Rupatadine pretreatment reduced the previously mentioned parameters, preserved a nearly normal intestinal mucosa picture with replenished GSH and elevated IL-10. In conclusion, rupatadine is a dual histamine receptor 1, and a PAF blocker could reduce 5-FU-induced oxidative damage, inflammation, apoptosis, and ulceration of the intestinal epithelium. Rupatadine may be a valuable modality to decrease 5-FU induced intestinal mucositis.