The Molecular Mechanism of the Catalase Reaction

Sniffer restricts arboviral brain infections by regulating ROS levels and protecting blood-brain barrier integrity in Drosophila and mosquitoes

Arthropod-borne viruses (arboviruses) are transmitted to humans by arthropod vectors and pose a serious threat to global public health. Neurotropic arboviruses including Sindbis virus (SINV) persistently infect the central nervous system (CNS) of vector insects without causing notable pathological changes or affecting their behavior or lifespan. However, the mechanisms by which vector insects evade these viral infections in the brains are poorly understood. In this study, we found that loss of the carbonyl reductase Sniffer (Sni) led to a significant increase in SINV infection in the Drosophila brain. Sni regulates reactive oxygen species (ROS) levels, and its depletion leads to elevated ROS, which in turn disrupts the septate junctions (SJs) between subperineurial glia (SPG) cells, compromising the integrity and barrier function of the blood-brain barrier (BBB). Genetic and pharmacological reduction of ROS restored BBB integrity and reduced viral load in the brains of Sni-depleted flies. Additionally, we identified Sni homologs and revealed that the antiviral function of Sni is highly conserved in mosquitoes, where it regulates ROS and protects BBB integrity. Our results revealed an evolutionarily conserved antiviral mechanism in which Sni acts as an antioxidant that protects BBB integrity and restricts viral infection in the vector insect brain.

A rapid and simple micro-assay to assess catalase activity in individual mosquito tissues

Oxidative stress generated as a normal byproduct of aerobic metabolism is minimized by the enzyme catalase (CAT; EC 1.11.1.6), which reduces hydrogen peroxide to molecular oxygen and water. In various mosquitoes, hydrogen peroxide and/or CAT activity have been implicated in oxidative responses to viral and protozoal pathogens as well as in ovarian maturation and insecticide resistance. We combined features of various CAT assays to develop a simple micro-assay that enables comparison of enzyme activities in individual mosquito tissues on a microscope slide. Activity recovered in the supernatant of mosquito whole body homogenates was inhibited by the CAT-specific inhibitor 3-amino-1,2,4-triazole. Activity was higher in blood-fed mosquitoes, consistent with exogenous enzyme in vertebrate blood. Triton X-100 improved evaluation of dissected organs, and accurate comparisons required careful removal of extraneous tissues. In unfed mosquitoes baseline CAT activity was lower in ovaries than in midgut or fatbody, but increased as oocytes matured after a blood meal, and was detectable in a single mature egg. CAT has unusual kinetics and can be difficult to assay directly. Our observations provide a simple approach for direct evaluation of CAT activity independent of changes in transcript levels and results of RNAi-based interference.

Translocation mechanism and the role of aerenchyma in nanoplastic translocation in Myriophyllum sp. "Roraima" and physiological responses

Nanoplastics have become a growing concern due to their potential impact on freshwater vegetation. The uptake, translocation, and effects of 0.05-µm nanoplastics on Myriophyllum sp. "Roraima" were investigated, along with the role of aerenchyma in nanoplastic transport. Microscopic observations revealed nanoplastic particle adsorption to the plant surface and entry into the roots and stems, with higher abundance and more dispersed distribution by direct contact. Nanoplastic particles were detected in the plant stem, primarily concentrated in regions adjacent to the aerenchyma. No morphological effects were observed. Induced changes in photosynthesis, including increased maximum quantum efficiency of photosystem II (Fv/Fm), decreased non-photochemical quenching (NPQ), decreased photosynthetic pigments, and increased photoprotective pigments, were recognized. Additionally, hydrogen peroxide levels and antioxidant enzyme activities varied in response to nanoplastic exposure. This study provides insights into the impact of nanoplastics on Myriophyllum sp. "Roraima" and has reviewed the underlying mechanisms, highlighting the role of aerenchyma in nanoplastic transport within the plant. Moreover, this study contributes to the understanding of the potential impacts of nanoplastic pollution on freshwater macrophytes while acknowledging the influence of phyto-anatomical structure on nanoplastic translocation.

Aptamer and DNAzyme Based Colorimetric Biosensors for Pathogen Detection

The detection of pathogens is critical for preventing and controlling health hazards across clinical, environmental, and food safety sectors. Functional nucleic acids (FNAs), such as aptamers and DNAzymes, have emerged as versatile molecular tools for pathogen detection due to their high specificity and affinity. This review focuses on the in vitro selection of FNAs for pathogens, with emphasis on the selection of aptamers for specific biomarkers and intact pathogens, including bacteria and viruses. Additionally, the selection of DNAzymes for bacterial detection is discussed. The integration of these FNAs into colorimetric biosensors has enabled the development of simple, cost-effective diagnostic platforms. Both non-catalytic and catalytic colorimetric biosensors are explored, including those based on gold nanoparticles, polydiacetylenes, protein enzymes, G-quadruplexes, and nanozymes. These biosensors offer visible detection through color changes, making them ideal for point-of-care diagnostics. The review concludes by highlighting current challenges and future perspectives for advancing FNA-based colorimetric biosensing technologies for pathogen detection.

Extracts ofHylotelephiumerythrostictum (miq.) H. Ohba ameliorate intestinal injury by scavenging ROS and inhibiting multiple signaling pathways in Drosophila

BACKGROUND

The intestinal epithelial barrier is the first line of defense against pathogens and noxious substances entering the body from the outside world. Through proliferation and differentiation, intestinal stem cells play vital roles in tissue regeneration, repair, and the maintenance of intestinal homeostasis. Inflammatory bowel disease (IBD) is caused by the disruption of intestinal homeostasis through the invasion of toxic compounds and pathogenic microorganisms. Hylotelephium erythrostictum (Miq.) H. Ohba (H. erythrostictum) is a plant with diverse pharmacological properties, including antioxidant, anti-inflammatory, antidiabetic, and antirheumatic properties. However, the roles of H. erythrostictum and its bioactive compounds in the treatment of intestinal injury are unknown.

METHODS

We examined the protective effects of H. erythrostictum water extract (HEWE) and H. erythrostictum butanol extract (HEBE) on Drosophila intestinal injury caused by dextran sodium sulfate (DSS) or Erwinia carotovoracarotovora 15 (Ecc15).

RESULTS

Our findings demonstrated that both HEWE and HEBE significantly prolonged the lifespan of flies fed toxic compounds, reduced cell mortality, and maintained intestinal integrity and gut acid‒base homeostasis. Furthermore, both HEWE and HEBE eliminated DSS-induced ROS accumulation, alleviated the increases in antimicrobial peptides(AMPs) and intestinal lipid droplets caused by Ecc15 infection, and prevented excessive ISC proliferation and differentiation by inhibiting the JNK, EGFR, and JAK/STAT pathways. In addition, they reversed the significant changes in the proportions of the gut microbiota induced by DSS. The bioactive compounds contained in H. erythrostictum extracts have sufficient potential for use as natural therapeutic agents for the treatment of IBD in humans.

CONCLUSION

Our results suggest that HEWE and HEBE are highly effective in reducing intestinal inflammation and thus have the potential to be viable therapeutic agents for the treatment of gut inflammation.

CLINICAL TRIAL NUMBER

Not applicable.

The Effect of Pomegranate Peel Extract on the Oxidative and Inflammatory Status in the Spleens of Rats with Metabolic Syndrome

Polyphenols have antioxidant and anti-inflammatory properties and maintain the immune system in balance; therefore, the aim of the study was to investigate the effect of polyphenols present in pomegranate peel extract on the spleens of rats with metabolic syndrome. The study objects were adult male Zucker Diabetic Fatty (ZDF-Leprfa/Crl, fa/fa) rats. The rats were divided into a control group (MetS) consisting of rats with metabolic syndrome and four study groups consisting of rats with metabolic syndrome (MetS + 100 mg and MetS + 200 mg) or healthy animals (H + 100 mg and H + 200 mg) receiving polyphenol extract at a dose of 100 mg or 200 mg/kg, respectively. Concentrations of IL-6, NF-κB, NFATc1, Cyt-C, TNFα, MMP-2, ROS/RNS, and MDA were measured; the activities of GPX, SOD, CAT, MMP-2, and MMP-9 were assessed; and the expression of the BAX and BCL-2 genes was evaluated in homogenized spleens. In conclusion, pomegranate extract may lead to an increase in catalase and glutathione peroxidase activity. Additionally, it may have a reducing effect on the ROS/RNS level, leading to a reduction in the activity of SOD in the MetS groups with PPE administration. Moreover, the BCL-2 gene showed lower expression in the MetS + 100 mg group compared to the H + 100 mg group, indicating that the balance between pro- and antiapoptotic factors of the BCL-2 family may be disrupted by the metabolic syndrome promoting the proapoptotic pathway.

Mechanistic characterization of iron-catalyzed oxidation of polysorbate 80: The role of ferrous iron, hydrogen peroxide, and superoxide

We investigated the role of individual radical species during Fe-catalyzed oxidation of PS80. Solutions containing 1 gL-1 PS80 (0.1 % w/v) in 10 mM acetate buffer (pH 6) were exposed to various amounts of either Fe(II) or Fe(III), hydrogen peroxide (H2O2), and various enzymes or antioxidants. PS80 oxidation was measured using a fluorescence micelle assay (FMA) alongside LC-MS. Hydrogen peroxide inhibited PS80 oxidation in the presence of Fe(II) but promoted oxidation in the presence of Fe(III). Furthermore, Ferrostatin-1 (Fer-1), an antioxidant which is known to preferentially react with alkoxy radicals, inhibited PS80 oxidation in the presence of Fe(II). Superoxide dismutase (SOD) partially inhibited PS80 oxidation in the presence of either Fe(II) or Fe(III), suggesting that superoxide plays a role in both cases. Ferryl species (FeIV=O) or hydroxyl radicals (HO•), produced by the Fenton reaction, do not play a major role in the oxidation of PS80. Rather, oxidation was initiated by the reaction of both Fe(II) and Fe(III) with pre-existing lipid hydroperoxides on PS80, as well as via superoxide.

Catalase-associated immune responses in plant-microbe interactions: A review

Catalase, an enzyme central to maintaining redox balance and combating oxidative stress in plants, has emerged as a key player in plant defense mechanisms and interactions with microbes. This review article provides a comprehensive analysis of catalase-associated immune responses in plant-microbe interactions. It underscores the importance of catalase in plant defense mechanisms, highlights its influence on plant susceptibility to pathogens, and discusses its implications for understanding plant immunity and host-microbe dynamics. This review contributes to the growing body of knowledge on catalase-mediated immune responses and offers insights that can aid in the development of strategies for improved plant health and disease resistance.

Role of Aralkylamine N-Acetyltransferase in the Response to Antioxidative Stress in the Fruit Fly Drosophila Melanogaster Adults

In multicellular organisms, the indole melatonin synthesized by aralkylamine N-acetyltransferase (AANATI) serves as an antioxidant. To test this, sex-mixed 3-day-old mated fly adults bw1 and AANAT1 homozygous recessive loss-of-function mutant (bw AANAT1lo) of Drosophila melanogaster were fed by a standard diet or by one containing paraquat (PQ, 1,1'-dimethyl-4,4'-bipyridilium dichloride hydrate) at a final concentration of 15.5 mM. Experiment lasted 8 h and began at 11 a.m. In bw1 flies the paraquat treatment resulted in a significant (evaluated by Student's t-tests) decrease of the superoxide dismutase (SOD) activity and an increase the catalase (CAT) and glutathione S-transferase (GST) activities. Meanwhile, in these flies, total Antioxidative capacity (TAC) was significantly curbed by the paraquat presence. Importantly, these changes were not observed in the AANAT1-mutants. Thus, melatonin seems to play an important defence role against the oxidative stress elicited by paraquat.

Metabolic dysfunction-associated steatotic liver disease-induced changes in the antioxidant system: a review

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a heterogeneous condition characterized by liver steatosis, inflammation, consequent fibrosis, and cirrhosis. Chronic impairment of lipid metabolism is closely related to oxidative stress, leading to cellular lipotoxicity, mitochondrial dysfunction, and endoplasmic reticulum stress. The detrimental effect of oxidative stress is usually accompanied by changes in antioxidant defense mechanisms, with the alterations in antioxidant enzymes expression/activities during MASLD development and progression reported in many clinical and experimental studies. This review will provide a comprehensive overview of the present research on MASLD-induced changes in the catalytic activity and expression of the main antioxidant enzymes (superoxide dismutases, catalase, glutathione peroxidases, glutathione S-transferases, glutathione reductase, NAD(P)H:quinone oxidoreductase) and in the level of non-enzymatic antioxidant glutathione. Furthermore, an overview of the therapeutic effects of vitamin E on antioxidant enzymes during the progression of MASLD will be presented. Generally, at the beginning of MASLD development, the expression/activity of antioxidant enzymes usually increases to protect organisms against the increased production of reactive oxygen species. However, in advanced stage of MASLD, the expression/activity of several antioxidants generally decreases due to damage to hepatic and extrahepatic cells, which further exacerbates the damage. Although the results obtained in patients, in various experimental animal or cell models have been inconsistent, taken together the importance of antioxidant enzymes in MASLD development and progression has been clearly shown.

Regulation of Mitochondrial and Peroxisomal Metabolism in Female Obesity and Type 2 Diabetes

Obesity and type 2 diabetes (T2D) are widespread metabolic disorders that significantly impact global health today, affecting approximately 17% of adults worldwide with obesity and 9.3% with T2D. Both conditions are closely linked to disruptions in lipid metabolism, where peroxisomes play a pivotal role. Mitochondria and peroxisomes are vital organelles responsible for lipid and energy regulation, including the β-oxidation and oxidation of very long-chain fatty acids (VLCFAs), cholesterol biosynthesis, and bile acid metabolism. These processes are significantly influenced by estrogens, highlighting the interplay between these organelles' function and hormonal regulation in the development and progression of metabolic diseases, such as obesity, metabolic dysfunction-associated fatty liver disease (MAFLD), and T2D. Estrogens modulate lipid metabolism through interactions with nuclear receptors, like peroxisome proliferator-activated receptors (PPARs), which are crucial for maintaining metabolic balance. Estrogen deficiency, such as in postmenopausal women, impairs PPAR regulation, leading to lipid accumulation and increased risk of metabolic disorders. The disruption of peroxisomal-mitochondrial function and estrogen regulation exacerbates lipid imbalances, contributing to insulin resistance and ROS accumulation. This review emphasizes the critical role of these organelles and estrogens in lipid metabolism and their implications for metabolic health, suggesting that therapeutic strategies, including hormone replacement therapy, may offer potential benefits in treating and preventing metabolic diseases.

Maternal Obesity Alters Placental and Umbilical Cord Plasma Oxidative Stress, a Cross-Sectional Study

Maternal obesity has been shown to impair the oxidative status in the placenta and newborns, potentially leading to adverse pregnancy outcomes and long-term effects on the programming of offspring metabolic status. This study aimed to investigate the impact of maternal obesity on maternal and umbilical cord plasma oxidative status, as well as placental oxidative adaptation. Maternal obesity (n = 20), defined as a pre-pregnancy BMI ≥ 25 kg/m2, and maternal leanness (n = 20), defined as a pre-pregnancy BMI < 23 kg/m2, were the group categories used in this study. Both groups were matched according to gestational age at delivery. Maternal blood, umbilical cord blood, and placental tissue were collected to assess nutritional content (cholesterol, triglyceride, and protein), oxidative stress markers (MDA and protein carbonyl), and antioxidant activity (SOD and catalase). Placental protein expression (SOD2, catalase, UCP2, and Nrf2) was evaluated using Western blot analysis. Catalase activity in maternal plasma significantly increased in the maternal obesity group (p = 0.0200), with a trend toward increased MDA and protein carbonyl levels. In umbilical cord plasma, triglyceride, protein carbonyl, and catalase activity were significantly elevated in the maternal obesity group compared with the lean controls (p = 0.0482, 0.0291, and 0.0347, respectively). Placental protein expression analysis revealed significantly decreased SOD2 (p = 0.0011) and catalase (p < 0.0001), along with Nrf2 downregulation (p < 0.0001). An increase in mitochondrial antioxidant UCP2 expression was observed (p = 0.0117). The neonatal protein carbonyl levels positively correlated with placental protein carbonyl (r = 0.7405, p < 0.0001) and negatively correlated with maternal catalase activity (r = -0.4332, p = 0.0052). This study thus provides evidence that maternal obesity is associated with placental and fetal oxidative stress, alongside a concurrent increase in placental antioxidant UCP2 expression.

Oxidative stress: fundamentals and advances in quantification techniques

Oxidative species, generated endogenously via metabolism or from exogenous sources, play crucial roles in the body. At low levels, these species support immune functions by participating in phagocytosis. They also aid in cellular signaling and contribute to vasomodulation. However, when the levels of oxidative species exceed the body's antioxidant capacity to neutralize them, oxidative stress occurs. This stress can damage cellular macromolecules such as lipids, DNA, RNA, and proteins, driving the pathogenesis of diseases and aging through the progressive deterioration of physiological functions and cellular structures. Therefore, the body's ability to manage oxidative stress and maintain it at optimal levels is essential for overall health. Understanding the fundamentals of oxidative stress, along with its reliable quantification, can enable consistency and comparability in clinical practice across various diseases. While direct quantification of oxidant species in the body would be ideal for assessing oxidative stress, it is not feasible due to their high reactivity, short half-life, and the challenges of quantification using conventional techniques. Alternatively, quantifying lipid peroxidation, damage products of nucleic acids and proteins, as well as endogenous and exogenous antioxidants, serves as appropriate markers for indicating the degree of oxidative stress in the body. Along with the conventional oxidative stress markers, this review also discusses the role of novel markers, focusing on their biological samples and detection techniques. Effective quantification of oxidative stress may enhance the understanding of this phenomenon, aiding in the maintenance of cellular integrity, prevention of age-associated diseases, and promotion of longevity.

Effect of oxygen generating nanozymes on indocyanine green and IR 820 mediated phototherapy against oral cancer

The hypoxic environment within a solid tumor is a limitation to the effectiveness of photodynamic therapy. Here, we demonstrate the use of oxygen generating nanozymes (CeO2, Fe3O4, and MnO2) to improve the photodynamic effect. The optimized combination of process parameters for irradiation was obtained using the Box Behnken experimental design. Indocyanine green, IR 820, and their different combinations with oxygen generators were studied for their effect on oral carcinoma. Dynamic light scattering technique showed the average particle size of CeO2, MnO2, and Fe3O4 to be 211 ± 16, and 157 ± 28, 143 ± 19 nm with PDI of 0.23, 0.28 and 0.20 and a zeta potential of -2.6 ± 0.45, -2.4 ± 0.60 and  -6.1 ± 0.23 mV, respectively. The formation of metal oxides was confirmed using UV-visible, FTIR, and X-ray photon spectroscopies. The amount of dissolved oxygen produced by CeO2, MnO2, and Fe3O4 in the presence of H2O2 within 2 min was 1.7 ± 0.15, 1.7 ± 0.16, and 1.4 ± 0.12 mg/l, respectively. Growth inhibition studies in the FaDu oral carcinoma spheroid model showed a significant (P < 0.05) increase in growth reduction from 81 ± 2.9 and 88 ± 2.1% to 97 ± 1.2 and 99 ± 1.0% for ICG and IR 820, respectively, after irradiation (808 nm laser, 1 W/cm2, 5 min) in the presence of CeO2 (25 μg/ml). In conclusion, oxygen-generating nanozymes can improve the photodynamic effect of ICG and IR 820.

Modulation of pulsed electric field induced oxidative processes in protein solutions by pro- and antioxidants sensed by biochemiluminescence

Technologies based on pulsed electric field (PEF) are increasingly pervasive in medical and industrial applications. However, the detailed understanding of how PEF acts on biosamples including proteins at the molecular level is missing. There are indications that PEF might act on biomolecules via electrogenerated reactive oxygen species (ROS). However, it is unclear how this action is modulated by the pro- and antioxidants, which are naturally present components of biosamples. This knowledge gap is often due to insufficient sensitivity of the conventionally utilized detection assays. To overcome this limitation, here we employed an endogenous (bio)chemiluminescence sensing platform, which enables sensitive detection of PEF-generated ROS and oxidative processes in proteins, to inspect effects of pro-and antioxidants. Taking bovine serum albumin (BSA) as a model protein, we found that the chemiluminescence signal arising from its solution is greatly enhanced in the presence ofH 2 O 2 as a prooxidant, especially during PEF treatment. In contrast, the chemiluminescence signal decreases in the presence of antioxidant enzymes (catalase, superoxide dismutase), indicating the involvement of bothH 2 O 2 and electrogenerated superoxide anion in oxidation-reporting chemiluminescence signal before, during, and after PEF treatment. We also performed additional biochemical and biophysical assays, which confirmed that BSA underwent structural changes afterH 2 O 2 treatment, with PEF having only a minor effect. We proposed a scheme describing the reactions leading from interfacial charge transfer at the anode by which ROS are generated to the actual photon emission. Results of our work help to elucidate the mechanisms of action of PEF on proteins via electrogenerated reactive oxygen species and open up new avenues for the application of PEF technology. The developed chemiluminescence technique enables label-free, in-situ and non-destructive sensing of interactions between ROS and proteins. The technique may be applied to study oxidative damage of other classes of biomolecules such as lipids, nucleic acids or carbohydrates.

Inflammation-free electrochemical in vivo sensing of dopamine with atomic-level engineered antioxidative single-atom catalyst

Electrochemical methods with tissue-implantable microelectrodes provide an excellent platform for real-time monitoring the neurochemical dynamics in vivo due to their superior spatiotemporal resolution and high selectivity and sensitivity. Nevertheless, electrode implantation inevitably damages the brain tissue, upregulates reactive oxygen species level, and triggers neuroinflammatory response, resulting in unreliable quantification of neurochemical events. Herein, we report a multifunctional sensing platform for inflammation-free in vivo analysis with atomic-level engineered Fe single-atom catalyst that functions as both single-atom nanozyme with antioxidative activity and electrode material for dopamine oxidation. Through high-temperature pyrolysis and catalytic performance screening, we fabricate a series of Fe single-atom nanozymes with different coordination configurations and find that the Fe single-atom nanozyme with FeN4 exhibits the highest activity toward mimicking catalase and superoxide dismutase as well as eliminating hydroxyl radical, while also featuring high electrode reactivity toward dopamine oxidation. These dual functions endow the single-atom nanozyme-based sensor with anti-inflammatory capabilities, enabling accurate dopamine sensing in living male rat brain. This study provides an avenue for designing inflammation-free electrochemical sensing platforms with atomic-precision engineered single-atom catalysts.

Dexamethasone Impairs ATP Production and Mitochondrial Performance in Human Trabecular Meshwork Cells

Mitochondrial damage occurs in human trabecular meshwork (HTM) cells as a result of normal aging and in open angle glaucoma. Using an HTM cell model, we quantified mitochondrial function and ATP generation rates after dexamethasone (Dex) and TGF-β2 treatments, frequently used as in vitro models of glaucoma. Primary HTM cells were assayed for metabolic function using a Seahorse XFp Analyzer. We additionally assessed the mitochondrial copy number and the expression of transcripts associated with mitochondrial biogenesis and oxidative stress regulation. Cells treated with Dex, but not TGF-β2, exhibited a significant decrease in total ATP production and ATP from oxidative phosphorylation relative to that of the control. Dex treatment also resulted in significant decreases in maximal respiration, ATP-linked O2 consumption, and non-mitochondrial O2 consumption. We did not observe significant changes in the level of mitochondrial genomes or mRNA transcripts of genes involved in mitochondrial biogenesis and oxidative stress regulation. Decreased mitochondrial performance and ATP production are consistent with the results of prior studies identifying the effects of Dex on multiple cell types, including HTM cells. Our results are also consistent with in vivo evidence of mitochondrial damage in open-angle glaucoma. Overall, these results demonstrate a decrease in mitochondrial performance in Dex-induced glaucomatous models in vitro, meriting further investigation.

Cellular and molecular mechanisms of hepatic ischemia-reperfusion injury: The role of oxidative stress and therapeutic approaches

Ischemia-reperfusion (IR) or reoxygenation injury is the paradoxical exacerbation of cellular impairment following restoration of blood flow after a period of ischemia during surgical procedures or other conditions. Acute interruption of blood supply to the liver and subsequent reperfusion can result in hepatocyte injury, apoptosis, and necrosis. Since the liver requires a continuous supply of oxygen for many biochemical reactions, any obstruction of blood flow can rapidly lead to hepatic hypoxia, which could quickly progress to absolute anoxia. Reoxygenation results in the increased generation of reactive oxygen species and oxidative stress, which lead to the enhanced production of proinflammatory cytokines, chemokines, and other signaling molecules. Consequent acute inflammatory cascades lead to significant impairment of hepatocytes and nonparenchymal cells. Furthermore, the expression of several vascular growth factors results in the heterogeneous closure of numerous hepatic sinusoids, which leads to reduced oxygen supply in certain areas of the liver even after reperfusion. Therefore, it is vital to identify appropriate therapeutic modalities to mitigate hepatic IR injury and subsequent tissue damage. This review covers all the major aspects of cellular and molecular mechanisms underlying the pathogenesis of hepatic ischemia-reperfusion injury, with special emphasis on oxidative stress, associated inflammation and complications, and prospective therapeutic approaches.

Curcumin Attenuates Doxorubicin-Induced Cardiac Oxidative Stress and Increases Survival in Mice

Doxorubicin (DOX) is a potent chemotherapeutic agent used to treat multiple types of cancer, but its clinical application is limited by cardiotoxicity, mainly due to oxidative stress. Curcumin (CUR) is a natural polyphenolic compound with strong antioxidant properties, but its potential protective effects against DOX-induced cardiotoxicity need further investigation. This study aimed to evaluate CUR's efficacy in mitigating DOX-induced oxidative stress in the hearts of BALB/c mice. Mice received a DOX dose of 9 mg/kg or 16 mg/kg; half of the mice received daily doses of 100 mg/kg CUR for 15 days. Survival analysis, histopathological examination, and oxidative stress markers were assessed to determine the cardioprotective effects of CUR. Results showed that CUR significantly reduced oxidative damage and improved survival rates, particularly at the lower DOX dose (9 mg/kg). Mice treated with DOX-9 mg/kg plus CUR showed improved health conditions and reduced levels of reactive oxygen species (ROS), lipid peroxidation, sulfhydryl production, and protein carbonylation. Histopathological analysis confirmed reduced cardiac tissue damage. In conclusion, CUR combined with a lower dose of DOX effectively reduces oxidative stress and cardiac injury, enhancing survival in BALB/c mice. These findings suggest that CUR is a promising adjunct therapy to mitigate DOX-induced cardiotoxicity, potentially improving the DOX therapeutic index in cancer treatment.

Protocellular Heme and Iron-Sulfur Clusters

ConspectusCentral to the quest of understanding the emergence of life is to uncover the role of metals, particularly iron, in shaping prebiotic chemistry. Iron, as the most abundant of the accessible transition metals on the prebiotic Earth, played a pivotal role in early biochemical processes and continues to be indispensable to modern biology. Here, we discuss our recent contributions to probing the plausibility of prebiotic complexes with iron, including heme and iron-sulfur clusters, in mediating chemistry beneficial to a protocell. Laboratory experiments and spectroscopic findings suggest plausible pathways, often facilitated by UV light, for the synthesis of heme and iron-sulfur clusters. Once formed, heme displays catalytic, peroxidase-like activity when complexed with amphiphiles. This activity could have been beneficial in two ways. First, heme could have catalytically removed a molecule (H2O2) that could have had degradative effects on a protocell. Second, heme could have helped in the synthesis of the building blocks of life by coupling the reduction of H2O2 with the oxidation of organic substrates. The necessity of amphiphiles to avoid the formation of inactive complexes of heme is telling, as the modern-day electron transport chain possesses heme embedded within a lipid membrane. Conversely, prebiotic iron-sulfur peptides have yet to be reported to partition into lipid membranes, nor have simple iron-sulfur peptides been found to be capable of participating in the synthesis of organic molecules. Instead, iron-sulfur peptides span a wide range of reduction potentials complementary to the reduction potentials of hemes. The reduction potential of iron-sulfur peptides can be tuned by the type of iron-sulfur cluster formed, e.g., [2Fe-2S] versus [4Fe-4S], or by the substitution of ligands to the metal center. Since iron-sulfur clusters easily form upon stochastic encounters between iron ions, hydrosulfide, and small organic molecules possessing a thiolate, including peptides, the likelihood of soluble iron-sulfur clusters seems to be high. What remains challenging to determine is if iron-sulfur peptides participated in early prebiotic chemistry or were recruited later when protocellular membranes evolved that were compatible with the exploitation of electron transfer for the storage of energy as a proton gradient. This problem mirrors in some ways the difficulty in deciphering the origins of metabolism as a whole. Chemistry that resembles some facets of extant metabolism must have transpired on the prebiotic Earth, but there are few clues as to how and when such chemistry was harnessed to support a (proto)cell. Ultimately, unraveling the roles of hemes and iron-sulfur clusters in prebiotic chemistry promises to deepen our understanding of the origins of life on Earth and aids the search for life elsewhere in the universe.

Fabrication of oxygen-releasing dextran microgels by droplet-based microfluidic method

In the tissue engineering field, the supply of oxygen to three-dimensional (3D) tissues is an important aspect to avoid necrosis due to hypoxia. Although oxygen-releasing bulk materials containing calcium peroxide (CaO2, CP) have attracted much attention, micrometer-sized oxygen-releasing soft materials would be advantageous because of their highly controllable structures, which can be applied for cell scaffolds, injectable materials, and bioink components in 3D bioprinting. In this study, oxygen-releasing microgels were fabricated via a droplet-based microfluidic system. Homogeneous, monodisperse and stable oxygen-releasing microgels were obtained by photo-crosslinking of droplets composed of biocompatible dextran modified with methacrylate groups and CP nanoparticles as an oxygen source. We also used our microfluidic system for the in situ amorphous calcium carbonate (CaCO3, ACC) formation on the surface of CP nanoparticles to achieve the controlled release of oxygen from the microgel. Oxygen release from an ACC-CP microgel in a neutral cell culture medium was suppressed because incorporation of CP in the ACC suppressed the reaction with water. Strikingly, stimuli to dissolve ACC such as a weak acidic conditions triggered the oxygen release from microgels loaded with ACC-CP, as the dissolution of CaCO3 allows CP to react. Taken together, applications of this new class of biomaterials for tissue engineering are greatly anticipated. In addition, the developed microfluidic system can be used for a variety of oxygen-releasing microgels by changing the substrates of the hydrogel network.

Pregnancy Disorders: A Potential Role for Mitochondrial Altered Homeostasis

Pregnancy is a complex and challenging process associated with physiological changes whose objective is to adapt the maternal organism to the increasing energetic requirements due to embryo and fetal development. A failed adaptation to these demands may lead to pregnancy complications that threaten the health of both mothers and their offspring. Since mitochondria are the main organelle responsible for energy generation in the form of ATP, the adequate state of these organelles seems crucial for proper pregnancy development and healthy pregnancy outcomes. The homeostasis of these organelles depends on several aspects, including their content, biogenesis, energy production, oxidative stress, dynamics, and signaling functions, such as apoptosis, which can be modified in relation to diseases during pregnancy. The etiology of pregnancy disorders like preeclampsia, fetal growth restriction, and gestational diabetes mellitus is not yet well understood. Nevertheless, insufficient placental perfusion and oxygen transfer are characteristic of many of them, being associated with alterations in the previously cited different aspects of mitochondrial homeostasis. Therefore, and due to the capacity of these multifactorial organelles to respond to physiological and pathophysiological stimuli, it is of great importance to gather the currently available scientific information regarding the relationship between main pregnancy complications and mitochondrial alterations. According to this, the present review is intended to show clear insight into the possible implications of mitochondria in these disorders, thus providing relevant information for further investigation in relation to the investigation and management of pregnancy diseases.

Two new members of the genus Sphingobacterium: Sphingobacterium zhuxiongii sp. nov. and Sphingobacterium luzhongxinii sp. nov

Four strains, designated dk4302T, dk4209, xlx-73T, and xlx-183, were isolated from Tibetan gazelle and red swamp crawfish collected from the Qinghai-Tibet Plateau and Jiangxi Province, PR China. The strains were Gram-stain-negative, aerobic, rod-shaped, non-motile, mucoid, and yellow-pigmented. Strains dk4302T and dk4209 grew at 10-40 °C and pH 6.0-9.0, while strains xlx-73T/xlx-183 grew at 15-40 °C and pH 6.0-10.0. Both strains exhibited growth in the presence of up to 3.5 % (w/v) NaCl. Phylogenetic and phylogenomic analyses based on the 16S rRNA gene sequences and 652 core genes, respectively, revealed that the four strains formed two distinct clusters in the genus Sphingobacterium. Strains dk4302T and dk4209 formed a distinct clade with Sphingobacterium hotanense XH4T and Sphingobacterium humi D1T. The most closely related strains to xlx-73T and xlx-183 were Sphingobacterium nematocida M-SX103T. The DNA G+C contents were 38.9 and 39.8 mol%. The digital DNA-DNA hybridization (dDDH) values between dk4302T and S. humi D1T and S. hotanense XH4T were 19.2 and 21.8 % (19.0 and 21.6 % for strain dk4209), respectively. The corresponding average nucleotide identity (ANI) values were 74.3 and 78.1 % (74.4 and 78.3 % for strain dk4209), respectively. The dDDH values between xlx-73T (xlx-183) and S. nematocida M-SX103T was 24.6 % (25.7 %). The corresponding ANI value was 85.7 % (85.5 % for strain xlx-183). The major fatty acid and respiratory quinone of dk4302T and xlx-73T were iso-C15:0 and MK7. The polar lipids identified in all of the novel strains were phosphatidylethanolamine, phosphoglycolipids, aminophospholipids, and phospholipids. A total of 61/190 (32.1 %) and 82/190 (43.2 %) carbon substrates were metabolized by strains dk4302T and xlx-73T in the Biolog MicroPlates, respectively. Based on the results from this polyphasic taxonomic study, two novel species in the genus Sphingobacteruim are proposed, namely Sphingobacteruim zhuxiongii sp. nov. (type strain dk4302T=CGMCC 1.16795T=JCM 33600T) and Sphingobacteruimluzhongxinii sp. nov. (type strain xlx-73T=GDMCC 1.1712T=JCM 33886T).

Design of Multivariate Biological Metal-Organic Frameworks: Toward Mimicking Active Sites of Enzymes

Mimicking enzymatic processes carried out by natural enzymes, which are highly efficient biocatalysts with key roles in living organisms, attracts much interest but constitutes a synthetic challenge. Biological metal-organic frameworks (bioMOFs) are potential candidates to be enzyme catalysis mimics, as they offer the possibility to combine biometals and biomolecules into open-framework porous structures capable of simulating the catalytic pockets of enzymes. In this work, we first study the catalase activity of a previously reported bioMOF, derived from the amino acid L-serine, with formula {CaIICuII6[(S,S)-serimox]3(OH)2(H2O)} · 39H2O (1) (serimox = bis[(S)-serine]oxalyl diamide), which is indeed capable to mimic catalase enzymes, in charge of preventing cell oxidative damage by decomposing, efficiently, hydrogen peroxide to water and oxygen (2H2O2 → 2 H2O + O2). With these results in hand, we then prepared a new multivariate bioMOF (MTV-bioMOF) that combines two different types of bioligands derived from L-serine and L-histidine amino acids with formula CaIICuII6[(S,S)-serimox]2[(S,S)-hismox]1(OH)2(H2O)}·27H2O (2) (hismox = bis[(S)-histidine]oxalyl diamide ligand). MTV-bioMOF 2 outperforms 1 degrading hydrogen peroxide, confirming the importance of the amino acid residue from the histidine amino acid acting as a nucleophile in the catalase degradation mechanism. Despite displaying a more modest catalytic behavior than other reported MOF composites, in which the catalase enzyme is immobilized inside the MOF, this work represents the first example of a MOF in which an attempt is made to replicate the active center of the catalase enzyme with its constituent elements and is capable of moderate catalytic activity.

The emerging role of oxidative stress in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic immune-mediated condition that affects the digestive system and includes Crohn's disease (CD) and ulcerative colitis (UC). Although the exact etiology of IBD remains uncertain, dysfunctional immunoregulation of the gut is believed to be the main culprit. Amongst the immunoregulatory factors, reactive oxygen species (ROS) and reactive nitrogen species (RNS), components of the oxidative stress event, are produced at abnormally high levels in IBD. Their destructive effects may contribute to the disease's initiation and propagation, as they damage the gut lining and activate inflammatory signaling pathways, further exacerbating the inflammation. Oxidative stress markers, such as malondialdehyde (MDA), 8-hydroxy-2'-deoxyguanosine (8-OHdG), and serum-free thiols (R-SH), can be measured in the blood and stool of patients with IBD. These markers are elevated in patients with IBD, and their levels correlate with the severity of the disease. Thus, oxidative stress markers can be used not only in IBD diagnosis but also in monitoring the response to treatment. It can also be targeted in IBD treatment through the use of antioxidants, including vitamin C, vitamin E, glutathione, and N-acetylcysteine. In this review, we summarize the role of oxidative stress in the pathophysiology of IBD, its diagnostic targets, and the potential application of antioxidant therapies to manage and treat IBD.

Unraveling UVB effects: Catalase activity and molecular alterations in the stratum corneum

AIM

Ultraviolet B (UVB) radiation can compromise the functionality of the skin barrier through various mechanisms. We hypothesize that UVB induce photochemical alterations in the components of the outermost layer of the skin, known as the stratum corneum (SC), and modulate its antioxidative defense mechanisms. Catalase is a well-known antioxidative enzyme found in the SC where it acts to scavenge reactive oxygen species. However, a detailed characterization of acute UVB exposure on the activity of native catalase in the SC is lacking. Moreover, the effects of UVB irradiation on the molecular dynamics and organization of the SC keratin and lipid components remain unclear. Thus, the aim of this work is to characterize consequences of UVB exposure on the structural and antioxidative properties of catalase, as well as on the molecular and global properties of the SC matrix surrounding the enzyme.

EXPERIMENTS

The effect of UVB irradiation on the catalase function is investigated by chronoamperometry with a skin covered oxygen electrode, which probes the activity of native catalase in the SC matrix. Circular dichroism is used to explore changes of the catalase secondary structure, and gel electrophoresis is used to detect fragmentation of the enzyme following the UVB exposure. UVB induced alterations of the SC molecular dynamics and structural features of the SC barrier, as well as its water sorption behavior, are investigated by a complementary set of techniques, including natural abundance 13C polarization transfer solid-state NMR, wide-angle X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, and dynamic vapor sorption microbalance.

FINDINGS

The findings show that UVB exposure impairs the antioxidative function of catalase by deactivating both native catalase in the SC matrix and lyophilized catalase. However, UVB radiation does not alter the secondary structure of the catalase nor induce any observable enzyme fragmentation, which otherwise could explain deactivation of its function. NMR measurements on SC samples show a subtle increase in the molecular mobility of the terminal segments of the SC lipids, accompanied by a decrease in the mobility of lipid chain trans-gauche conformers after high doses of UVB exposure. At the same time, the NMR data suggest increased rigidity of the polypeptide backbone of the keratin filaments, while the molecular mobility of amino acid residues in random coil domains of keratin remain unaffected by UVB irradiation. The FTIR data show a consistent decrease in absorbance associated with lipid bond vibrations, relative to the main protein bands. Collectively, the NMR and FTIR data suggest a small modification in the composition of fluid and solid phases of the SC lipid and protein components after UVB exposure, unrelated to the hydration capacity of the SC tissue. To conclude, UVB deactivation of catalase is anticipated to elevate oxidative stress of the SC, which, when coupled with subtle changes in the molecular characteristics of the SC, may compromise the overall skin health and elevate the likelihood of developing skin disorders.

Biomimetic-Structured Cobalt Nanocatalyst Suppresses Aortic Dissection Progression by Catalytic Antioxidation

As one of the most lethal cardiovascular diseases, aortic dissection (AD) is initiated by overexpression of reactive oxygen species (ROS) in the aorta that damages the vascular structure and finally leads to massive hemorrhage and sudden death. Current drugs used in clinics for AD treatment fail to efficiently scavenge ROS to a large extent, presenting undesirable therapeutic effect. In this work, a nanocatalytic antioxidation concept has been proposed to elevate the therapeutic efficacy of AD by constructing a cobalt nanocatalyst with a biomimetic structure that can scavenge pathological ROS in an efficient and sustainable manner. Theoretical calculations demonstrate that the antioxidation reaction is catalyzed by the redox transition between hydroxocobalt(III) and oxo-hydroxocobalt(V) accompanied by inner-sphere proton-coupled two-electron transfer, forming a nonassociated activation catalytic cycle. The efficient antioxidation action of the biomimetic nanocatalyst in the AD region effectively alleviates oxidative stress, which further modulates the aortic inflammatory microenvironment by promoting phenotype transition of macrophages. Consequently, vascular smooth muscle cells are also protected from inflammation in the meantime, suppressing AD progression. This study provides a nanocatalytic antioxidation approach for the efficient treatment of AD and other cardiovascular diseases.

Effects of hesperidin on the histological structure, oxidative stress, and apoptosis in the liver and kidney induced by NiCl2

The aim of this study was to investigate the effect of hesperidin on the liver and kidney dysfunctions induced by nickel. The mice were divided into six groups: nickel treatment with 80 mg/kg, 160 mg/kg, 320 mg/kg hesperidin groups, 0.5% CMC-Na group, nickel group, and blank control group. Histopathological techniques, biochemistry, immunohistochemistry, and the TUNEL method were used to study the changes in structure, functions, oxidative injuries, and apoptosis of the liver and kidney. The results showed that hesperidin could alleviate the weight loss and histological injuries of the liver and kidney induced by nickel, and increase the levels of lactate dehydrogenase (LDH), alanine aminotransferase (GPT), glutamic oxaloacetic transaminase (GOT) in liver and blood urea nitrogen (BUN), creatinine (Cr) and N-acetylglucosidase (NAG) in kidney. In addition, hesperidin could increase the activities of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and glutathione peroxidase (GSH-Px) in the liver and kidney, decrease the content of malondialdehyde (MDA) and inhibit cell apoptosis. It is suggested that hesperidin could help inhibit the toxic effect of nickel on the liver and kidney.

Advances in metal-organic framework-based nanozymes in ROS scavenging medicine

Reactive oxygen species (ROS) play important roles in regulating various physiological functions in the human body, however, excessive ROS can cause serious damage to the human body, considering the various limitations of natural enzymes as scavengers of ROS in the body, the development of better materials for the scavenging of ROS is of great significance to the biomedical field, and nanozymes, as a kind of nanomaterials which can show the activity of natural enzymes. Have a good potential for the development in the area of ROS scavenging. Metal-organic frameworks (MOFs), which are porous crystalline materials with a periodic network structure composed of metal nodes and organic ligands, have been developed with a variety of active nanozymes including catalase-like, superoxide dismutase-like, and glutathione peroxidase-like enzymes due to the adjustability of active sites, structural diversity, excellent biocompatibility, and they have shown a wide range of applications and prospects. In the present review, we first introduce three representative natural enzymes for ROS scavenging in the human body, methods for the detection of relevant enzyme-like activities and mechanisms of enzyme-like clearance are discussed, meanwhile, we systematically summarize the progress of the research on MOF-based nanozymes, including the design strategy, mechanism of action, and medical application, etc. Finally, the current challenges of MOF-based nanozymes are summarized, and the future development direction is anticipated. We hope that this review can contribute to the research of MOF-based nanozymes in the medical field related to the scavenging of ROS.

Exploring Therapeutic Potential of Catalase: Strategies in Disease Prevention and Management

The antioxidant defense mechanisms play a critical role in mitigating the deleterious effects of reactive oxygen species (ROS). Catalase stands out as a paramount enzymatic antioxidant. It efficiently catalyzes the decomposition of hydrogen peroxide (H2O2) into water and oxygen, a potentially harmful byproduct of cellular metabolism. This reaction detoxifies H2O2 and prevents oxidative damage. Catalase has been extensively studied as a therapeutic antioxidant. Its applications range from direct supplementation in conditions characterized by oxidative stress to gene therapy approaches to enhance endogenous catalase activity. The enzyme's stability, bioavailability, and the specificity of its delivery to target tissues are significant hurdles. Furthermore, studies employing conventional catalase formulations often face issues related to enzyme purity, activity, and longevity in the biological milieu. Addressing these challenges necessitates rigorous scientific inquiry and well-designed clinical trials. Such trials must be underpinned by sound experimental designs, incorporating advanced catalase formulations or novel delivery systems that can overcome existing limitations. Enhancing catalase's stability, specificity, and longevity in vivo could unlock its full therapeutic potential. It is necessary to understand the role of catalase in disease-specific contexts, paving the way for precision antioxidant therapy that could significantly impact the treatment of diseases associated with oxidative stress.

Chemomechanical Communication between Liposomes Based on Enzyme Cascades

Communication between cells is crucial to the survival of both uni- and multicellular organisms. The primary mode of communication involves chemical cues. There is great current interest in mimicking this behavior in synthetic cells to understand the physical basis of intercellular communication and design collective functional behavior. Using liposomal cell mimics, we demonstrate how a chemical input can elicit a mechanical response (enhanced motility). We employed a single substrate to trigger enzyme cascade-induced control of the diffusion of up to three different liposome populations. Furthermore, substrate competition allows temporal control over enhanced diffusion. The use of enzyme cascades to propagate chemical signals provides a robust and efficient mechanism for diverse populations of protocells to coordinate their motion in response to signals from each other.

Assessment of Hippocampal-Related Behavioral Changes in Adolescent Rats of both Sexes Following Voluntary Intermittent Ethanol Intake and Noise Exposure: A Putative Underlying Mechanism and Implementation of a Non-pharmacological Preventive Strategy

Ethanol (EtOH) intake and noise exposure are particularly concerning among human adolescents because the potential to harm brain. Unfortunately, putative underlying mechanisms remain to be elucidated. Moreover, implementing non-pharmacological strategies, such as enriched environments (EE), would be pertinent in the field of neuroprotection. This study aims to explore possible underlying triggering mechanism of hippocampus-dependent behaviors in adolescent animals of both sexes following ethanol intake, noise exposure, or a combination of both, as well as the impact of EE. Adolescent Wistar rats of both sexes were subjected to an intermittent voluntary EtOH intake paradigm for one week. A subgroup of animals was exposed to white noise for two hours after the last session of EtOH intake. Some animals of both groups were housed in EE cages. Hippocampal-dependent behavioral assessment and hippocampal oxidative state evaluation were performed. Results show that different hippocampal-dependent behavioral alterations might be induced in animals of both sexes after EtOH intake and sequential noise exposure, that in some cases are sex-specific. Moreover, hippocampal oxidative imbalance seems to be one of the potential underlying mechanisms. Additionally, most behavioral and oxidative alterations were prevented by EE. These findings suggest that two frequently found environmental agents may impact behavior and oxidative pathways in both sexes in an animal model. In addition, EE resulted a partially effective neuroprotective strategy. Therefore, it could be suggested that the implementation of a non-pharmacological approach might also potentially provide neuroprotective advantages against other challenges. Finally, considering its potential for translational human benefit might be worth.

Mechanism of oxalate decarboxylase Oxd_S12 from Bacillus velezensis BvZ45-1 in defence against cotton verticillium wilt

Verticillium wilt, a soilborne vascular disease caused by Verticillium dahliae, strongly affects cotton yield and quality. In this study, an isolated rhizosphere bacterium, designated Bacillus velezensis BvZ45-1, exhibited >46% biocontrol efficacy against cotton verticillium wilt under greenhouse and field conditions. Moreover, through crude protein extraction and mass spectrometry analyses, we found many antifungal compounds present in the crude protein extract of BvZ45-1. The purified oxalate decarboxylase Odx_S12 from BvZ45-1 inhibited the growth of V. dahliae Vd080 by reducing the spore yield, causing mycelia to rupture, spore morphology changes, cell membrane rupture, and cell death. Subsequently, overexpression of Odx_S12 in Arabidopsis significantly improved plant resistance to V. dahliae. Through studies of the resistance mechanism of Odx_S12, V. dahliae was shown to produce oxalic acid (OA), which has a toxic effect on Arabidopsis leaves. Odx_S12 overexpression reduced Arabidopsis OA content, enhanced tolerance to OA, and improved resistance to verticillium wilt. Transcriptomics and quantitative real-time PCR analysis revealed that Odx_S12 promoted a reactive oxygen species burst and a salicylic acid- and abscisic acid-mediated defence response in Arabidopsis. In summary, this study not only identified B. velezensis BvZ45-1 as an efficient biological control agent, but also identified the resistance gene Odx_S12 as a candidate for cotton breeding against verticillium wilt.

Microenzymes: Is There Anybody Out There?

Biological macromolecules are found in different shapes and sizes. Among these, enzymes catalyze biochemical reactions and are essential in all organisms, but is there a limit size for them to function properly? Large enzymes such as catalases have hundreds of kDa and are formed by multiple subunits, whereas most enzymes are smaller, with molecular weights of 20-60 kDa. Enzymes smaller than 10 kDa could be called microenzymes and the present literature review brings together evidence of their occurrence in nature. Additionally, bioactive peptides could be a natural source for novel microenzymes hidden in larger peptides and molecular downsizing could be useful to engineer artificial enzymes with low molecular weight improving their stability and heterologous expression. An integrative approach is crucial to discover and determine the amino acid sequences of novel microenzymes, together with their genomic identification and their biochemical biological and evolutionary functions.

Transition-Metal-Based Nanozymes: Synthesis, Mechanisms of Therapeutic Action, and Applications in Cancer Treatment

Cancer, as one of the leading causes of death worldwide, drives the advancement of cutting-edge technologies for cancer treatment. Transition-metal-based nanozymes emerge as promising therapeutic nanodrugs that provide a reference for cancer therapy. In this review, we present recent breakthrough nanozymes for cancer treatment. First, we comprehensively outline the preparation strategies involved in creating transition-metal-based nanozymes, including hydrothermal method, solvothermal method, chemical reduction method, biomimetic mineralization method, and sol-gel method. Subsequently, we elucidate the catalytic mechanisms (catalase (CAT)-like activities), peroxidase (POD)-like activities), oxidase (OXD)-like activities) and superoxide dismutase (SOD)-like activities) of transition-metal-based nanozymes along with their activity regulation strategies such as morphology control, size manipulation, modulation, composition adjustment and surface modification under environmental stimulation. Furthermore, we elaborate on the diverse applications of transition-metal-based nanozymes in anticancer therapies encompassing radiotherapy (RT), chemodynamic therapy (CDT), photodynamic therapy (PDT), photothermal therapy (PTT), sonodynamic therapy (SDT), immunotherapy, and synergistic therapy. Finally, the challenges faced by transition-metal-based nanozymes are discussed alongside future research directions. The purpose of this review is to offer scientific guidance that will enhance the clinical applications of nanozymes based on transition metals.

Enzyme-mimic catalytic activities and biomedical applications of noble metal nanoclusters

Noble metal (e.g., Au and Ag) nanoclusters (NCs), which exhibit structural complexity and hierarchy comparable to those of natural proteins, have been increasingly pursued in artificial enzyme research. The protein-like structure of metal NCs not only ensures enzyme-mimic catalytic activity, including peroxidase-, catalase-, and superoxide dismutase-mimic activities, but also affords an unprecedented opportunity to correlate the catalytic performance with the cluster structure at the molecular or atomic levels. In this review, we aim to summarize the recent progress in programming and demystify the enzyme-mimic catalytic activity of metal NCs, presenting the state-of-the-art understandings of the structure-property relationship of metal NC-based artificial enzymes. By leveraging on a concise anatomy of the hierarchical structure of noble metal NCs, we manage to unravel the structural origin of the catalytic performance of metal NCs. Noteworthily, it has been proven that the surface ligands and metal-ligand interface of metal NCs are instrumental in influencing enzyme-mimic catalytic activities. In addition to the structure-property correlation, we also discuss the synthetic methodologies feasible to tailoring the cluster structure at the atomic level. Prior to the closure of this review with our perspectives in noble metal NC-based artificial enzymes, we also exemplify the biomedical applications based on the enzyme-mimic catalysis of metal NCs with the theranostics of kidney injury, brain inflammation, and tumors. The fundamental and methodological advancements delineated in this review would be conducive to further development of metal NCs as an alternative family of artificial enzymes.

Dissolved organic matter accelerates microbial degradation of 17 alpha-ethinylestradiol in the presence of iron mineral

Dissolved organic matter (DOM) and iron minerals widely existing in the natural aquatic environment can mediate the migration and transformation of organic pollutants. However, the mechanism of interaction between DOM and iron minerals in the microbial degradation of pollutants deserves further investigation. In this study, the mechanism of 17 alpha-ethinylestradiol (EE2) biodegradation mediated by humic acid (HA) and three kinds of iron minerals (goethite, magnetite, and pyrite) was investigated. The results found that HA and iron minerals significantly accelerated the biodegradation process of EE2, and the highest degradation efficiency of EE2 (48%) was observed in the HA-mediated microbial system with pyrite under aerobic conditions. Furthermore, it had been demonstrated that hydroxyl radicals (HO•) was the main active substance responsible for the microbial degradation of EE2. HO• is primarily generated through the reaction between hydrogen peroxide secreted by microorganisms and Fe(II), with aerobic conditions being more conducive. The presence of iron minerals and HA could change the microbial communities in the EE2 biodegradation system. These findings provide new information for exploring the migration and transformation of pollutants by microorganisms in iron-rich environments.

Research progress on the role of reactive oxygen species in the initiation, development and treatment of breast cancer

According to international cancer data, breast cancer (BC) is the leading type of cancer in women. Although significant progress has been made in treating BC, metastasis and drug resistance continue to be the primary causes of mortality for many patients. Reactive oxygen species (ROS) play a dual role in vivo: normal levels can maintain the body's normal physiological function; however, high levels of ROS below the toxicity threshold can lead to mtDNA damage, activation of proto-oncogenes, and inhibition of tumor suppressor genes, which are important causes of BC. Differences in the production and regulation of ROS in different BC subtypes have important implications for the development and treatment of BC. ROS can also serve as an important intracellular signal transduction factor by affecting the antioxidant system, activating MAPK and PI3K/AKT, and other signal pathways to regulate cell cycle and change the relationship between cells and the activity of metalloproteinases, which significantly impacts the metastasis of BC. Hypoxia in the BC microenvironment increases ROS production levels, thereby inducing the expression of hypoxia inducible factor-1α (HIF-1α) and forming "ROS- HIF-1α-ROS" cycle that exacerbates BC development. Many anti-BC therapies generate sufficient toxic ROS to promote cancer cell apoptosis, but because the basal level of ROS in BC cells exceeds that of normal cells, this leads to up-regulation of the antioxidant system, drug efflux, and apoptosis inhibition, rendering BC cells resistant to the drug. ROS crosstalks with tumor vessels and stromal cells in the microenvironment, increasing invasiveness and drug resistance in BC.

Mechanisms of chondrocyte regulated cell death in osteoarthritis: Focus on ROS-triggered ferroptosis, parthanatos, and oxeiptosis

Osteoarthritis (OA) is a common chronic inflammatory degenerative disease. Since chondrocytes are the only type of cells in cartilage, their survival is critical for maintaining cartilage morphology. This review offers a comprehensive analysis of how reactive oxygen species (ROS), including superoxide anions, hydrogen peroxide, hydroxyl radicals, nitric oxide, and their derivatives, affect cartilage homeostasis and trigger several novel modes of regulated cell death, including ferroptosis, parthanatos, and oxeiptosis, which may play roles in chondrocyte death and OA development. Moreover, we discuss potential therapeutic strategies to alleviate OA by scavenging ROS and provide new insight into the research and treatment of the role of regulated cell death in OA.

Iron, Copper, and Selenium: Cancer's Thing for Redox Bling

Cells require micronutrients for numerous basic functions. Among these, iron, copper, and selenium are particularly critical for redox metabolism, and their importance is heightened during oncogene-driven perturbations in cancer. In this review, which particularly focuses on iron, we describe how these micronutrients are carefully chaperoned about the body and made available to tissues, a process that is designed to limit the toxicity of free iron and copper or by-products of selenium metabolism. We delineate perturbations in iron metabolism and iron-dependent proteins that are observed in cancer, and describe the current approaches being used to target iron metabolism and iron-dependent processes.

Sevoflurane Exposure Induces Neuronal Cell Ferroptosis Initiated by Increase of Intracellular Hydrogen Peroxide in the Developing Brain via ER Stress ATF3 Activation

Neuronal cell death is acknowledged as the primary pathological basis underlying developmental neurotoxicity in response to sevoflurane exposure, but the exact mechanism remains unclear. Ferroptosis is a form of programmed cell death characterized by iron-dependent lipid peroxidation that is driven by hydrogen peroxide (H2O2) and ferrous iron through the Fenton reaction and participates in the pathogenesis of multiple neurological diseases. As stress response factor, activating transcription factor 3 (ATF3) can be activated by the PERK/ATF4 pathway during endoplasmic reticulum (ER) stress, followed by increased intracellular H2O2, which is involved in regulation of apoptosis, autophagy, and ferroptosis. Here, we investigated whether ferroptosis and ATF3 activation were implicated in sevoflurane-induced neuronal cell death in the developing brain. The results showed that sevoflurane exposure induced neuronal death as a result of iron-dependent lipid peroxidation damage secondary to H2O2 accumulation and ferrous iron increase, which was consistent with the criteria for ferroptosis. Furthermore, we observed that increases in iron and H2O2 induced by sevoflurane exposure were associated with the upregulation and nuclear translocation of ATF3 in response to ER stress. Knockdown of ATF3 expression alleviated iron-dependent lipid peroxidation, which prevented sevoflurane-induced neuronal ferroptosis. Mechanistically, ATF3 promoted sevoflurane-induced H2O2 accumulation by activating NOX4 and suppressing catalase, GPX4, and SLC7A11 expression. Additionally, an increase in H2O2 was accompanied by the upregulation of TFR and TF and downregulation of FPN, which linked iron overload to ferroptosis induced by sevoflurane. Taken together, our results demonstrated that ER stress-mediated ATF3 activation contributed to sevoflurane-induced neuronal ferroptosis via H2O2 accumulation and the resultant iron overload.

A ferrocene-based hydrogel as flexible electrochemical biosensor for oxidative stress detection and antioxidation treatment

Real-time sensing of reactive oxygen species (ROS) and timely scavenging of excessive ROS in physiological environments are critically important in the diagnosis and prevention of ROS-related diseases. To solve the mismatch problem between conventional rigid ROS biosensors and biological tissues in terms of both modulus and composition, here, we present a flexible ferrocene-based hydrogel biosensor designed for oxidative stress detection and antioxidation treatment. The hydrogel was fabricated through a supramolecular assembly of ferrocene-grafted polyethylenimine (PEI-Fc), sodium alginate (SA), and polyvinyl alcohol (PVA). Multiple non-covalent interactions, including electrostatic interactions between PEI-Fc and SA, hydrophobic interactions and π-π stacking among ferrocene groups, and the PVA crystalline domain, synergistically improve the mechanical properties of the PVA/SA/PEI-Fc hydrogel. The flexible PVA/SA/PEI-Fc hydrogel biosensor exhibited a broad detection range for hydrogen peroxide (H2O2), from 0 to 120 μM, using the differential pulse voltammetry method. Furthermore, the hydrogel demonstrated effective ROS scavenging and oxygen generation performance, desirable biocompatibility, and satisfactory antibacterial activity, making it suitable for biological interfaces. In vitro studies revealed that the PVA/SA/PEI-Fc hydrogel could monitor H2O2 concentration in the proximity of inflammatory cells, and effectively scavenge ROS to protect cells from oxidative stress damage. This all-in-one multifunctional hydrogel, integrating both sensing and treatment functions, holds great promise for clinical applications in the diagnosis and management of ROS-related diseases.

Antibacterial Ingredients and Modes of the Methanol-Phase Extract from the Fruit of Amomum villosum Lour

Epidemics of infectious diseases threaten human health and society stability. Pharmacophagous plants are rich in bioactive compounds that constitute a safe drug library for antimicrobial agents. In this study, we have deciphered for the first time antibacterial ingredients and modes of the methanol-phase extract (MPE) from the fruit of Amomum villosum Lour. The results have revealed that the antibacterial rate of the MPE was 63.64%, targeting 22 species of common pathogenic bacteria. The MPE was further purified by high performance liquid chromatography (Prep-HPLC), and three different constituents (Fractions 1-3) were obtained. Of these, the Fraction 2 treatment significantly increased the cell membrane fluidity and permeability, reduced the cell surface hydrophobicity, and damaged the integrity of the cell structure, leading to the leakage of cellular macromolecules of Gram-positive and Gram-negative pathogens (p < 0.05). Eighty-nine compounds in Fraction 2 were identified by ultra HPLC-mass spectrometry (UHPLC-MS) analysis, among which 4-hydroxyphenylacetylglutamic acid accounted for the highest 30.89%, followed by lubiprostone (11.86%), miltirone (10.68%), and oleic acid (10.58%). Comparative transcriptomics analysis revealed significantly altered metabolic pathways in the representative pathogens treated by Fraction 2 (p < 0.05), indicating multiple antibacterial modes. Overall, this study first demonstrates the antibacterial activity of the MPE from the fruit of A. villosum Lour., and should be useful for its application in the medicinal and food preservative industries against common pathogens.

Redox regulation in lifespan determination

One of the major challenges that remain in the fields of aging and lifespan determination concerns the precise roles that reactive oxygen species (ROS) play in these processes. ROS, including superoxide and hydrogen peroxide, are constantly generated as byproducts of aerobic metabolism, as well as in response to endogenous and exogenous cues. While ROS accumulation and oxidative damage were long considered to constitute some of the main causes of age-associated decline, more recent studies reveal a signaling role in the aging process. In fact, accumulation of ROS, in a spatiotemporal manner, can trigger beneficial cellular responses that promote longevity and healthy aging. In this review, we discuss the importance of timing and compartmentalization of external and internal ROS perturbations in organismal lifespan and the role of redox regulated pathways.

Insight on thermal stress response of demosponge Chondrosia reniformis (Nardo, 1847)

Global warming has led to an increase in extreme weather and climate phenomena, including floods and heatwaves. Marine heatwaves have frightening consequences for coastal benthic communities around the world. Each species exhibits a natural range of thermal tolerance and responds to temperature variations through behavioral, physiological, biochemical, and molecular adjustments. Physiological stress leading to disease and mass mortality appears when tolerance thresholds are exceeded. Sessile species are therefore particularly affected by these phenomena. Among these sessile species, marine sponges are important members of coral reef ecosystems. To better understand the sponge thermal stress response, we tested the response of demosponge Chondrosia reniformis (Nardo, 1847) to three different temperatures (8 °C, 24 °C and 30 °C) during two exposure periods of time (4 and 14 h). Histological studies of whole parts of the sponge, biochemical analyses (Defense enzymes) and gene expression levels of some target genes were undertaken in this study. The exposure to cold temperature (8 °C) resulted in inhibition of antioxidant enzymes and less modification in the gene expression level of the heat shock proteins (HSPs). These latter were strongly upregulated after exposure to a temperature of 24 °C for 4 h. However, exposure to 30 °C at both periods of time resulted in indication of HSP, antioxidant enzymes, the gene involved in the apoptosis process (Bcl-2: B-cell lymphoma 2), the gene involved in inflammation (TNF: Tumor Necrosis Factor), as well as the aquaporin gene, involved in H2O2 permeation. Moreover, the normal organization of the whole organism was disrupted by the extension and fusion of choanocyte chambers and alteration of the pinacoderm. Interestingly, exposure to sublethal temperatures may show that this sponge has an adaptation threshold temperature. These insights into the adaptation mechanisms of sponges contribute to better management and conservation of sponges and to the prediction of ecosystem trajectories with future climate change.

Inorganic Fe-O and Fe-S oxidoreductases: paradigms for prebiotic chemistry and the evolution of enzymatic activity in biology

Oxidoreductases play crucial roles in electron transfer during biological redox reactions. These reactions are not exclusive to protein-based biocatalysts; nano-size (<100 nm), fine-grained inorganic colloids, such as iron oxides and sulfides, also participate. These nanocolloids exhibit intrinsic redox activity and possess direct electron transfer capacities comparable to their biological counterparts. The unique metal ion architecture of these nanocolloids, including electron configurations, coordination environment, electron conductivity, and the ability to promote spontaneous electron hopping, contributes to their transfer capabilities. Nano-size inorganic colloids are believed to be among the earliest 'oxidoreductases' to have 'evolved' on early Earth, playing critical roles in biological systems. Representing a distinct type of biocatalysts alongside metalloproteins, these nanoparticles offer an early alternative to protein-based oxidoreductase activity. While the roles of inorganic nano-sized catalysts in current Earth ecosystems are intuitively significant, they remain poorly understood and underestimated. Their contribution to chemical reactions and biogeochemical cycles likely helped shape and maintain the balance of our planet's ecosystems. However, their potential applications in biomedical, agricultural, and environmental protection sectors have not been fully explored or exploited. This review examines the structure, properties, and mechanisms of such catalysts from a material's evolutionary standpoint, aiming to raise awareness of their potential to provide innovative solutions to some of Earth's sustainability challenges.

Peroxymonosulfate activation by trace iron(III) porphyrin for facile degradation of organic pollutants via nonradical oxidation

Nonradical species with great resistance to interference have shown great advantages in complex wastewater treatment. Herein, a novel system constructed by biodegradable tetrakis-(4-carboxyphenyl)-porphyrinatoiron(III) (FeIII-TCPP) and peroxymonosulfate (PMS) was proposed for facile decontamination. Nonradical pathway is observed in FeIII-TCPP/PMS, where 1O2 and high-valent iron-oxo species play dominant roles. The genres and valence of high-valent iron-oxo species, including iron(IV)-oxo porphyrin radical-cationic species [OFeIV-TCPP•+] and iron(IV)-hydroxide species [FeIV-TCPP(OH)], are ascertained, along with their generation mechanism. The axial ligand on the iron axial site affects the ground spin state of FeIII-TCPP, further influencing the thermodynamic reaction pathway of active species. With trace catalyst in micromoles, FeIII-TCPP exhibits high efficiency by degrading bisphenol S (BPS) completely within 5 min, while Co2+/PMS can only achieve a maximum of 26.2% under identical condition. Beneficial from nonradical pathways, FeIII-TCPP/PMS demonstrates a wide pH range of 3-10 and exhibits minimal sensitivity to interference of concomitant materials. BPS is primarily eliminated through β-scission and hydroxylation. Specifically, 1O2 electrophilically attacks the C-S bond of BPS, while high-valent iron-oxo species interacts with BPS through an oxygen-bound mechanism. This study provides novel insights into efficient activation of PMS by iron porphyrin, enabling the removal of refractory pollutants through nonradical pathway.

Hollow Copper Sulfide Photothermal Nanodelivery Platform Boosts Angiogenesis of Diabetic Wound by Scavenging Reactive Oxygen Species

Sharply rising oxidative stress and ineffectual angiogenesis have imposed restrictions on diabetic wound healing. Here, a photothermal-responsive nanodelivery platform (HHC) was prepared by peroxidase (CAT)-loaded hollow copper sulfide dispersed in photocurable methacrylamide hyaluronan. The HHC could scavenge reactive oxygen species (ROS) and promote angiogenesis by photothermally driven CAT and Cu2+ release. Under near-infrared light irradiation, the HHC presented safe photothermal performance (<43 °C), efficient bacteriostatic ability against E. coli and S. aureus. It could rapidly release CAT into the external environment for decomposing H2O2 and oxygen generation to alleviate oxidative stress while promoting fibroblast migration and VEGF protein expression of endothelial cells by reducing intracellular ROS levels. The nanodelivery platform presented satisfactory therapeutic effects on murine diabetic wound healing by modulating tissue inflammation, promoting collagen deposition and increasing vascularization in the neodermis. This HHC provided a viable strategy for diabetic wound dressing design.

The chemical characteristics of different sodium iron ethylenediaminetetraacetate sources and their relative bioavailabilities for broilers fed with a conventional corn-soybean meal diet

BACKGROUND

Our previous studies demonstrated that divalent organic iron (Fe) proteinate sources with higher complexation or chelation strengths as expressed by the greater quotient of formation (Qf) values displayed higher Fe bioavailabilities for broilers. Sodium iron ethylenediaminetetraacetate (NaFeEDTA) is a trivalent organic Fe source with the strongest chelating ligand EDTA. However, the bioavailability of Fe when administered as NaFeEDTA in broilers and other agricultural animals remains untested. Herein, the chemical characteristics of 12 NaFeEDTA products were determined. Of these, one feed grade NaFeEDTA (Qf = 2.07 × 108), one food grade NaFeEDTA (Qf = 3.31 × 108), and one Fe proteinate with an extremely strong chelation strength (Fe-Prot ES, Qf value = 8,590) were selected. Their bioavailabilities relative to Fe sulfate (FeSO4·7H2O) for broilers fed with a conventional corn-soybean meal diet were evaluated during d 1 to 21 by investigating the effects of the above Fe sources and added Fe levels on the growth performance, hematological indices, Fe contents, activities and gene expressions of Fe-containing enzymes in various tissues of broilers.

RESULTS

NaFeEDTA sources varied greatly in their chemical characteristics. Plasma Fe concentration (PI), transferrin saturation (TS), liver Fe content, succinate dehydrogenase (SDH) activities in liver, heart, and kidney, catalase (CAT) activity in liver, and SDH mRNA expressions in liver and kidney increased linearly (P < 0.05) with increasing levels of Fe supplementation. However, differences among Fe sources were detected (P < 0.05) only for PI, liver Fe content, CAT activity in liver, SDH activities in heart and kidney, and SDH mRNA expressions in liver and kidney. Based on slope ratios from multiple linear regressions of the above indices on daily dietary analyzed Fe intake, the average bioavailabilities of Fe-Prot ES, feed grade NaFeEDTA, and food grade NaFeEDTA relative to the inorganic FeSO4·7H2O (100%) for broilers were 139%, 155%, and 166%, respectively.

CONCLUSIONS

The bioavailabilities of organic Fe sources relative to FeSO4·7H2O were closely related to their Qf values, and NaFeEDTA sources with higher Qf values showed higher Fe bioavailabilities for broilers fed with a conventional corn-soybean meal diet.

Epigenetic mechanisms of particulate matter exposure: air pollution and hazards on human health

Environmental pollution nowadays has not only a direct correlation with human health changes but a direct social impact. Epidemiological studies have evidenced the increased damage to human health on a daily basis because of damage to the ecological niche. Rapid urban growth and industrialized societies importantly compromise air quality, which can be assessed by a notable accumulation of air pollutants in both the gas and the particle phases. Of them, particulate matter (PM) represents a highly complex mixture of organic and inorganic compounds of the most variable size, composition, and origin. PM being one of the most complex environmental pollutants, its accumulation also varies in a temporal and spatial manner, which challenges current analytical techniques used to investigate PM interactions. Nevertheless, the characterization of the chemical composition of PM is a reliable indicator of the composition of the atmosphere, the quality of breathed air in urbanized societies, industrial zones and consequently gives support for pertinent measures to avoid serious health damage. Epigenomic damage is one of the most promising biological mechanisms of air pollution-derived carcinogenesis. Therefore, this review aims to highlight the implication of PM exposure in diverse molecular mechanisms driving human diseases by altered epigenetic regulation. The presented findings in the context of pan-organic cancer, fibrosis, neurodegeneration and metabolic diseases may provide valuable insights into the toxicity effects of PM components at the epigenomic level and may serve as biomarkers of early detection for novel targeted therapies.