Manganese Superoxide Dismutase Research Articles

Mechano-induced cell metabolism disrupts the oxidative stress homeostasis of SAOS-2 osteosarcoma cells

There has been an increasing focus on cancer mechanobiology, determining the underlying-induced changes to unlock new avenues in the modulation of cell malignancy. Our study used LC-MS untargeted metabolomic approaches and real-time polymerase chain reaction (PCR) to characterize the molecular changes induced by a specific moderate uniaxial stretch regimen (i.e., 24 h-1 Hz, cyclic stretch 0,5% elongation) on SAOS-2 osteosarcoma cells. Differential metabolic pathway analysis revealed that the mechanical stimulation induces a downregulation of both glycolysis and the tricarboxylic acid (TCA) cycle. At the same time, the amino acid metabolism was found to be dysregulated, with the mechanical stimulation enhancing glutaminolysis and reducing the methionine cycle. Our findings showed that cell metabolism and oxidative defense are tightly intertwined in mechanically stimulated cells. On the one hand, the mechano-induced disruption of the energy cell metabolism was found correlated with an antioxidant glutathione (GSH) depletion and an accumulation of reactive oxygen species (ROS). On the other hand, we showed that a moderate stretch regimen could disrupt the cytoprotective gene transcription by altering the expression levels of manganese superoxide dismutase (SOD1), Sirtuin 1 (SIRT1), and NF-E2-related factor 2 (Nrf2) genes. Interestingly, the cyclic applied strain could induce a cytotoxic sensitization (to the doxorubicin-induced cell death), suggesting that mechanical signals are integral regulators of cell cytoprotection. Hence, focusing on the mechanosensitive system as a therapeutic approach could potentially result in more effective treatments for osteosarcoma in the future.

The Effect of Barley Bran Polyphenol-Rich Extracts on the Development of Nonalcoholic Steatohepatitis in Sprague–Dawley Rats Fed a High-Fat and High-Cholesterol Diet

Oxidative stress and inflammation play a central role in the progression of nonalcoholic steatohepatitis (NASH), which can lead to liver cirrhosis. Barley bran has potential bioactivities due to its high content of functional substances, such as anthocyanins, with anti-inflammatory and anti-oxidative properties. Here, we investigated whether barley bran polyphenol-rich extracts (BP) can prevent NASH in Sprague–Dawley rats fed a high-fat and high-cholesterol diet including 1.25% or 2.5% cholesterol for 9 weeks. In the rat model of NASH with advanced hepatic fibrosis, BP prevented NASH development by ameliorating the histopathological findings of lobular inflammation. The BP also tended to attenuate serum aspartate aminotransferase level in this model. In the rat model of NASH with mild-to-moderate hepatic fibrosis, BP tended to attenuate the serum levels of transaminases. BP-dose-dependent effects were revealed for several parameters, including monocyte chemoattractant protein-1, transforming growth factor-β, and manganese superoxide dismutase gene expressions in the liver. These results suggest that BP may prevent NASH development or progression, presumably due to its anti-inflammatory and anti-oxidative properties.

Manganese- and Platinum-Driven Oxidative and Nitrosative Stress in Oxaliplatin-Associated CIPN with Special Reference to Ca4Mn(DPDP)5, MnDPDP and DPDP.

Platinum-containing chemotherapeutic drugs are efficacious in many forms of cancer but are dose-restricted by serious side effects, of which peripheral neuropathy induced by oxidative-nitrosative-stress-mediated chain reactions is most disturbing. Recently, hope has been raised regarding the catalytic antioxidants mangafodipir (MnDPDP) and calmangafodipir [Ca4Mn(DPDP)5; PledOx®], which by mimicking mitochondrial manganese superoxide dismutase (MnSOD) may be expected to overcome oxaliplatin-associated chemotherapy-induced peripheral neuropathy (CIPN). Unfortunately, two recent phase III studies (POLAR A and M trials) applying Ca4Mn(DPDP)5 in colorectal cancer (CRC) patients receiving multiple cycles of FOLFOX6 (5-FU + oxaliplatin) failed to demonstrate efficacy. Instead of an anticipated 50% reduction in the incidence of CIPN in patients co-treated with Ca4Mn(DPDP)5, a statistically significant increase of about 50% was seen. The current article deals with confusing differences between early and positive findings with MnDPDP in comparison to the recent findings with Ca4Mn(DPDP)5. The POLAR failure may also reveal important mechanisms behind oxaliplatin-associated CIPN itself. Thus, exacerbated neurotoxicity in patients receiving Ca4Mn(DPDP)5 may be explained by redox interactions between Pt2+ and Mn2+ and subtle oxidative-nitrosative chain reactions. In peripheral sensory nerves, Pt2+ presumably leads to oxidation of the Mn2+ from Ca4Mn(DPDP)5 as well as from Mn2+ in MnSOD and other endogenous sources. Thereafter, Mn3+ may be oxidized by peroxynitrite (ONOO-) into Mn4+, which drives site-specific nitration of tyrosine (Tyr) 34 in the MnSOD enzyme. Conformational changes of MnSOD then lead to the closure of the superoxide (O2•-) access channel. A similar metal-driven nitration of Tyr74 in cytochrome c will cause an irreversible disruption of electron transport. Altogether, these events may uncover important steps in the mechanism behind Pt2+-associated CIPN. There is little doubt that the efficacy of MnDPDP and its therapeutic improved counterpart Ca4Mn(DPDP)5 mainly depends on their MnSOD-mimetic activity when it comes to their potential use as rescue medicines during, e.g., acute myocardial infarction. However, pharmacokinetic considerations suggest that the efficacy of MnDPDP on Pt2+-associated neurotoxicity depends on another action of this drug. Electron paramagnetic resonance (EPR) studies have demonstrated that Pt2+ outcompetes Mn2+ and endogenous Zn2+ in binding to fodipir (DPDP), hence suggesting that the previously reported protective efficacy of MnDPDP against CIPN is a result of chelation and elimination of Pt2+ by DPDP, which in turn suggests that Mn2+ is unnecessary for efficacy when it comes to oxaliplatin-associated CIPN.

Ginsenoside Re protects against kainate-induced neurotoxicity in mice by attenuating mitochondrial dysfunction through activation of the signal transducers and activators of transcription 3 signaling

It was demonstrated that ginsenosides exert anti-convulsive potentials and interleukin-6 (IL-6) is protective from excitotoxicity induced by kainate (KA), a model of temporal lobe epilepsy. Ginsenosides-mediated mitochondrial recovery is essential for attenuating KA-induced neurotoxicity, however, little is known about the effects of ginsenoside Re (GRe), one of the major ginsenosides. In this study, GRe significantly attenuated KA-induced seizures in mice. KA-induced redox changes were more evident in mitochondrial fraction than in cytosolic fraction in the hippocampus of mice. GRe significantly attenuated KA-induced mitochondrial oxidative stress (i.e., increases in reactive oxygen species, 4-hydroxynonenal, and protein carbonyl) and mitochondrial dysfunction (i.e., the increase in intra-mitochondrial Ca2+ and the decrease in mitochondrial membrane potential). GRe or mitochondrial protectant cyclosporin A restored phospho-signal transducers and activators of transcription 3 (STAT3) and IL-6 levels reduced by KA, and the effects of GRe were reversed by the JAK2 inhibitor AG490 and the mitochondrial toxin 3-nitropropionic acid (3-NP). Thus, we used IL-6 knockout (KO) mice to investigate whether the interaction between STAT3 and IL-6 is involved in the GRe effects. Importantly, KA-induced reduction of manganese superoxide dismutase (SOD-2) levels and neurodegeneration (i.e., astroglial inhibition, microglial activation, and neuronal loss) were more prominent in IL-6 KO than in wild-type (WT) mice. These KA-induced detrimental effects were attenuated by GRe in WT and, unexpectedly, IL-6 KO mice, which were counteracted by AG490 and 3-NP. Our results suggest that GRe attenuates KA-induced neurodegeneration via modulating mitochondrial oxidative burden, mitochondrial dysfunction, and STAT3 signaling in mice.

Modulations in antioxidant defence system and expression of genes involved in antioxidant and apoptosis pathway helps ward-off heat stress incows reared in hot-arid ambience of Thar desert

The present study was designed to assess the seasonal perturbations in key antioxidant parameters: ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) scavenging activity, lipid per oxidation (LPO), uric acid and reduced glutathione (GSH) assay along with expression profile of genes that regulate the antioxidant pathway: manganese superoxide dismutase (SOD2), Glutathione Peroxidase 1 (GPX1) and apoptosis pathway: B-cell lymphoma 2 (BCL2) and Bcl-2-associated X protein (BAX) in the two crucial indicine cattle breeds- Sahiwal and Kankrej. The study was carried out in the hot-arid region of Rajasthan across four seasons, wherein, the meteorological parameters were recorded across seasons to calculate the prevailing temperature-humidity index (THI) to assess the extent of heat load on cows. The study revealed huge diurnal variations in the temperature across four seasons, while the THI during summer and hot-humid seasons was well in excess of 80, highlighting significant heat stress on cows. All the key antioxidant parameters, except GSH registered an increase with the incremental THI. The transcriptional profile of SOD2 and GPX1 mRNA expression revealed significantly higher expression during the higher THI months of both summer and hot-humid seasons. The expression pattern of BAX and BCL2 mRNA in PBMCs of Sahiwal cows revealed an initial induction during the month of summer season with significantly higher expression, followed by a decline by the hot-humid season. The findings highlight a crucial role played by antioxidant defence and genes regulating apoptosis pathway in thermotolerance of indicine cattle breeds.

First Report of Colletotrichum fructicola Causing Leaf Spot on Smilax glabra Roxb in China.

Smilax glabra Roxb is a medicinal plant distributed in 17 countries and used in the production of food and tea (Wu et al. 2022). In May 2021, a leaf spot disease was observed on ~60% of S. glabra plants in a field (∼0.4 ha) in Qinzhou City, Guangxi Province. Initially, small, circular, brown spots appeared on the leaf surfaces, which then gradually expanded into large, sunken, dark brown necrotic areas. As disease progressed, lesions merged into large spots, eventually leading to defoliation. To determine the causal agent, six symptomatic plants were collected from the field. Small pieces (∼5 mm2) were cut from the infected leaves (n = 12), sterilized for two min in 1% NaOCl, and rinsed three times in sterile water. Then, the leaf tissues were placed on potato dextrose agar (PDA) with chloramphenicol (0.1 g/liter) and incubated for 3 days at 28°C (12-h photoperiod). Pure cultures were obtained by transferring hyphal tips from recently germinated spores or colony edges onto PDA. Among the 17 isolates, 15 exhibited similar morphologies. Two single-spore isolates (TFL45.1 and TFL46.2) were subjected to further morphological and molecular characterization. Colonies on PDA were grayish green with a white outer ring and cottony surface, and pale blackish green on the reverse side. Conidia were hyaline, aseptate, straight, and cylindrical, with rounded ends, and 11.4 to 16.5 μm × 4.1 to 6.1 μm (average 13.9 × 4.8 μm, n = 100). Appressoria were brown to dark brown, with a smooth edge and different shapes such as ovoid, elliptical or irregular, and 6.8 to 8.9 μm × 5.9 to 7.8 μm (average 7.7 × 6.6 μm, n = 25). For molecular identification, eight target gene sequences, internal transcribed spacer (ITS), glyceraldehydes-3-phosphate dehydrogenase (GAPHD), calmodulin (CAL), partial actin (ACT), chitin synthase (CHS-1), glutamine synthetase (GS), manganese superoxide dismutase (SOD2), and β-tubulin (TUB) were selected for PCR amplification (Weir et al. 2012). The resulting sequences were deposited in GenBank (OR399160-61 and OR432537-50). BLASTn analysis of the obtained sequences showed 99-100% identity with those of the ex-type strain C. fructicola ICMP:18581 (JX010165, JX010033, FJ917508, FJ907426, JX009866, JX010095, JX010327, JX010405) (Weir et al. 2012). In addition, a phylogenetic analysis confirmed the isolates as C. fructicola. Therefore, based on morphological and molecular characteristics (Park et al. 2018; Weir et al. 2012), the isolates were identified as C. fructicola. To verify pathogenicity, three healthy leaves on each of six two-year-old S. glabra plants were inoculated with ∼5 mm2 mycelial discs or aliquots of 10 μl suspension (106 conidia/ml) of the strain TFL46.2, and six control plants were inoculated with sterile PDA discs or sterile water. All plants were enclosed in plastic bags and incubated in a greenhouse at 25°C (12-h photoperiod). Six days post-inoculation, leaf spot symptoms appeared on the inoculated leaves. No symptoms were detected in the controls. Experiments were replicated three times with similar results. To fulfill Koch's postulates, C. fructicola was consistently re-isolated from symptomatic tissue and confirmed by morphology and sequencing of the eight genes, whereas no fungus was isolated from the control plants. To our knowledge, this is the first report of C. fructicola causing leaf spot disease on S. glabra. Further studies will be needed to develop strategies against this disease based on the identification of this pathogen.

Effects of chronic hydrogen peroxide exposure on mitochondrial oxidative stress genes, ROS production and lipid peroxidation in HL60 cells

Hydrogen peroxide (H2O2) is a reactive species that is also involved in the redox regulation of cells because of it is relative stability. In numerous pathological situations, a chronic increase in the production of reactive species is observed, which is related to oxidative stress and cellular damage. This study aimed to evaluate the effects of long-term exposure to different H2O2 concentrations on oxidative stress biomarkers and mitochondrial dynamics in HL60 cells. HL60 cells were treated with a sustained production (0.1, 1.0 and 10.0 nM/s) of H2O2 for one hour. H2O2 production and malondialdehyde (MDA) levels, as a lipid peroxidation marker, increased progressively in HL60 cells in accordance with higher H2O2 exposure, with significant differences between the 10 nM/s H2O2 group and the control and 0.1 nM/s groups. Similarly, progressive increased expression in genes related to the mitochondrial antioxidant defences and mitochondrial dynamics were also observed. Significantly increased gene expression in the 10 nM/s H2O2 with respect to the control group was observed for manganese superoxide dismutase (MnSOD), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PCG1α), nuclear respiratory factor 2 (Nrf2), mitochondrial transcription factor A (Tfam), mitofusins 1 and 2 (Mfn1 and Mfn2) and uncoupling protein 3 (UCP3), whereas no significant changes were observed in the cytochrome c oxidase subunit IV (COXIV) gene expression. In conclusion, exposure to different sustained production of H2O2 is related to a progressive increase in the gene expression of mitochondrial dynamics and redox processes in HL60 cells, but also to oxidative damage at higher H2O2 production levels.

Relationship between Serum Homocysteine Levels and Manganese Superoxide Dismutase (MnSOD) on Retinal Nerve Fiber Layer (RNFL) Thickness in Diabetic Retinopathy and Non-Diabetic Retinopathy Patients

Introduction & ObjectivesDiabetic retinopathy is a visual disorder caused by abnormalities in the retina, where there is aprogressive microangiopathy characterized by damage and blockage of fine blood vessels, resultingin impaired nutrition of the retina. This study is to find out the relationship between serumhomocysteine levels and MnSOD on retinal nerve fiber layer (RNFL) thickness in diabeticretinopathy and non-diabetic retinopathy patients.
 MethodsThis study is an analytic observational case-control study with a total of 31 subjects for each group.3cc of venous blood samples were taken to assess the serum levels of homocysteine and MnSOD andthen analyzed by ELISA method in the integrated laboratory of the USU Medical Faculty.
 ResultsThere was a significant difference in Avg RNFL and Nasal RNFL thickness between the two groups(p=0.015) with the mean Avg RNFL thickness being 100.94 (SD=17.04) and the mean RNFL nasalthickness being 90.16 (SD=33.68). The highest MnSOD levels were found in non-diabeticretinopathy subjects with a mean of 142.77 (SD=101.77). There was no significant relationshipbetween homocysteine and thickness of superior RNFL (p=0.346), inferior RNFL (p=0.292),temporal RNFL (p=0.109), nasal RNFL (p=0.190). However, a significant association was foundbetween homocysteine and Avg RNFL (p=0.007).
 ConclusionIn the group of cases of diabetic retinopathy, a significant relationship was found between Hcy andAvg RNFL (p=0.007). An increase in serum homocysteine levels will be followed by a decrease in thethickness of the Avg RNFL.

Moringa oleifera fruit extract as a potential antioxidant against liver injury by 2-Nitropropane induction in obese male mice model: pre-clinical study

Background: Moringa oleifera fruit extract contains beneficial chemical compounds. This study was conducted to observed the power of antioxidant against liver injury by 2-Nitropropane induction in an obese male mice model. Methods: This research was in vivo laboratory experimental study with a post-test control design group only. The population was obese male mice models, Swiss strain, aged 6–8 weeks, weighing between 60–80 gr. The research sample was determined by Federer's formula for a complete randomized design experimental test, group N (control), O1 (induced by 2-Nitropropane intraperitoneal (i.p) once), O2 (induced by 2-Nitropropane i.p twice), P1 (induced by 2-Nitropropane i.p. once and gavage with M. oleifera fruit extract 500mg/kg bodyweight (BW) once a day), P2 (induced by 2-Nitropropane i.p. twice and gavage of M. oleifera fruit extract 500mg/kg BW once a day), and P3 (induced by 2-Nitropropane i.p. twice and gavage of vitamin C 500mg/kg BW once a day). Antioxidant potential parameters were measured by levels of malondialdehide (MDA), glutation (GSH), 8-hydroxy-2'-deoxyguanosine (8-OHdG), catalase activity, manganese superoxide dismutase (MnSOD), serum glutamic pyruvic transaminase (SGPT), serum glutamic oxaloacetic transaminase (SGOT). This research was held at the Biochemistry laboratory of Medicine Faculty, UPN Veteran Jakarta in May–September 2020. Analysis was carried out using SPSS version 20.0. The parameters were tested using ANOVA. Results: MDA levels decreased, GSH increased, 8-OHdG decreased, catalase activity increased, MnSOD activity increased and SGOT, SGPT levels decreased. M. oleifera fruit extract was statistically proven to be a candidate for potential antioxidant against liver injury of 2-Nitropropane induction in obese male mice model. Conclusions: M. oleifera fruit extract was statistically evident as an antioxidant substance that reduces oxidative stress in acute liver injury caused by 2-Nitropropane induction.

The P4' Peptide-Carrying Bacillus subtilis in Cottonseed Meal Improves the Chinese Mitten Crab Eriocheir sinensis Innate Immunity, Redox Defense, and Growth Performance.

This study developed a recombinant Bacillus subtilis to carry the LGSPDVIVIR peptide (cmP4) isolated from the hydrolyzed products of cottonseed meal with excellent antioxidant and immune-enhancing properties in vitro. It was carried as a tandem of five cmP4 peptides (cmP4') to be stably expressed on a large scale. Then, its effectiveness was evaluated in Chinese mitten crab (Eriocheir sinensis) based on growth performance, redox defense, and innate immunity. A total of 280 crabs (mean body weight: 41.40 ± 0.14) were randomly assigned to seven diets including a control one (without B. subtilis) and six experimental ones with different doses (107,108, and 109 CFU/kg) of unmodified and recombinant B. subtilis, respectively, for 12 weeks. Each diet was tested in four tanks of crabs (10/tank). In terms of bacterial dosages, the final weight (FW), weight gain (WG), hemolymph and hepatopancreatic activities of superoxide dismutase (SOD), catalase (CAT), lysosome (LZM), acid phosphatase (ACP) and alkaline phosphatase (AKP), and hepatopancreatic transcriptions of cat, mitochondrial manganese superoxide dismutase (mtmnsod), thioredoxin-1 (trx1), and prophenoloxidase (propo) all increased significantly with increasing B. subtilis dosages, while hemolymph and hepatopancreatic malondialdehyde (MDA) content and the transcriptions of toll like receptors (tlrs), NF-κB-like transcription factor (relish), and lipopolysaccharide-induced TNF-α factor (litaf) all decreased remarkably. In terms of bacterial species, the recombinant B. subtilis group obtained significantly high values of FW, WG, hemolymph, and hepatopancreatic activities of SOD, CAT, LZM, ACP, and AKP, and the transcriptions of mtmnsod, peroxiredoxin 6 (prx6), and propo compared with the unmodified B. subtilis, while opposite results were noted in hemolymph and hepatopancreatic MDA content and the transcriptions of tlrs, relish, and litaf. These results indicated that dietary supplementation with 109 CFU/kg of recombinant B. subtilis can improve the growth performance, redox defense, and nonspecific immunity of E. sinensis.

Distinct mechanisms underlying the therapeutic effects of low-molecular-weight heparin and chondroitin sulfate on Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder influenced by various factors, including age, genetics, and the environment. Current treatments provide symptomatic relief without impeding disease progression. Previous studies have demonstrated the therapeutic potential of exogenous heparin and chondroitin sulfate in PD. However, their therapeutic mechanisms and structure-activity relationships remain poorly understood. In this study, low-molecular-weight heparin (L-HP) and chondroitin sulfate (L-CS) exhibited favorable therapeutic effects in a mouse model of PD. Proteomics revealed that L-HP attenuated mitochondrial dysfunction through its antioxidant properties, whereas L-CS suppressed neuroinflammation by inhibiting platelet activation. Two glycosaminoglycan (GAG)-binding proteins, manganese superoxide dismutase (MnSOD2) and fibrinogen beta chain (FGB), were identified as potential targets of L-HP and L-CS, and we investigated their structure-activity relationships. The IdoA2S-GlcNS6S/GlcNAc6S unit in HP bound to SOD2, whereas the GlcA-GalNAc4S and GlcA-GalNAc4S6S units in CS preferred FGB. Furthermore, N-S and 2-O-S in L-HP, and 4-O-S, 6-O-S, and -COOH in L-CS contributed significantly to the binding process. These findings provide new insights and evidence for the development and use of glycosaminoglycan-based therapeutics for PD.

ENHANCED MITOCHONDRIAL BIOGENESIS INCREASES ANTI-OXIDANT ENZYMES AND IMPROVES TISSUE INFLAMMATION IN HUMAN IBD TISSUE

Abstract BACKGROUND In patients with inflammatory bowel disease (IBD), there exists a connection between mitochondrial dysfunction and two key issues: increased oxidative stress and attenuated ATP production. Previously we presented at this meeting the effect of a novel gold-based compound (AuPhos) on enhancing mitochondrial function in attenuating mice colitis (). In the present study we interrogate the effect of AuPhos on mitochondrial biogenesis in biopsies from control and active ulcerative colitis (UC) (Mayo 1-2) patients and normal human colonic epithelial cells (NCM460). We postulate that AuPhos-induced mitochondrial function enhances biogenesis and anti-oxidant levels and improves tissue inflammation in human IBD tissue. METHODS Effects of AuPhos on mitochondrial and anti-oxidant proteins were evaluated in NCM460 cells by western blot (WB) +/- low-dose TNF(1ng/ml). Human colonic biopsy samples (n=3) were collected and treated ex-vivo with vehicle or AuPhos (3h, 4oC), and processed for protein and mRNA analysis by WB and RT-qPCR, respectively. Flow cytometry of mitotracker green quantified mitochondrial mass in NCM460 and intestinal epithelial cells (IECs) from human control and UC tissues (n=3, Mayo 1-2). RESULTS AuPhos increased mitochondrial mass (mitotracker, Fig.1A,1B) and biogenesis protein levels PGC1α, NRF2 and TFAM (Fig.1C) in human intestinal epithelial cells (IECs), biopsies, and in NCM460 cells. Protein analysis in NCM460 cells show that AuPhos increases downstream antioxidant markers such as manganese superoxide dismutase (MnSOD), glutathione peroxidase 4 (GPX4), thioredoxin reductase2 (Trx2), and catalase expression when compared to the TNF or control samples. AuPhos substantially upregulates levels of mitochondria complex (mtCO1, mtCO2 Cox6A1, ATP5A1) and anti-oxidant enzyme (MnSOD, GPX, PRDX-2, -4, and -6) mRNA and protein levels in human colonic biopsies compared to vehicle and TNF treated samples (Fig. 1D). Furthermore, AuPhos reduces tissue cytokine and chemokine mRNA levels (IL1β, MCP1, RankL, and TNFα) in human UC tissues (Fig. 1E). CONCLUSIONS The current study reveals that AuPhos increases mitochondrial biogenesis, mitochondrial complex, and antioxidant enzyme levels in human IBD tissue. THE REDUCTION IN TISSUE CYTOKINES AND CHEMOKINES SUGGESTS THAT ENHANCED MITOCHONDRIAL FUNCTION IMPROVES TISSUE INFLAMMATION. This suggests the potential of AuPhos in treating IBD through the restoration of mitochondrial biogenesis.

Hfe Permease and Haemophilus influenzae Manganese Homeostasis.

Haemophilus influenzae is a commensal of the human upper respiratory tract that can infect diverse host niches due, at least in part, to its ability to withstand both endogenous and host-mediated oxidative stresses. Here, we show that hfeA, a gene previously linked to iron import, is essential for H. influenzae manganese recruitment via the HfeBCD transporter. Structural analyses show that metal binding in HfeA uses a unique mechanism that involves substantial rotation of the C-terminal lobe of the protein. Disruption of hfeA reduced H. influenzae manganese acquisition and was associated with decreased growth under aerobic conditions, impaired manganese-superoxide dismutase activity, reduced survival in macrophages, and changes in biofilm production in the presence of superoxide. Collectively, this work shows that HfeA contributes to H. influenzae manganese acquisition and virulence attributes. High conservation of the hfeABCD permease in Haemophilus species suggests that it may serve similar roles in other pathogenic Pasteurellaceae.

Effects of Particulate Matter Inhalation during Exercise on Oxidative Stress and Mitochondrial Function in Mouse Skeletal Muscle.

Particulate matter (PM) has deleterious consequences not only on the respiratory system but also on essential human organs, such as the heart, blood vessels, kidneys, and liver. However, the effects of PM inhalation on skeletal muscles have yet to be sufficiently elucidated. Female C57BL/6 or mt-Keima transgenic mice were randomly assigned to one of the following four groups: control (CON), PM exposure alone (PM), treadmill exercise (EX), or PM exposure and exercise (PME). Mice in the three-treatment group were subjected to treadmill running (20 m/min, 90 min/day for 1 week) and/or exposure to PM (100 μg/m3). The PM was found to exacerbate oxidative stress and inflammation, both at rest and during exercise, as assessed by the levels of proinflammatory cytokines, manganese-superoxide dismutase activity, and the glutathione/oxidized glutathione ratio. Furthermore, we detected significant increases in the levels of in vivo mitophagy, particularly in the PM group. Compared with the EX group, a significant reduction in the level of mitochondrial DNA was recorded in the PME group. Moreover, PM resulted in a reduction in cytochrome c oxidase activity and an increase in hydrogen peroxide generation. However, exposure to PM had no significant effect on mitochondrial respiration. Collectively, our findings in this study indicate that PM has adverse effects concerning both oxidative stress and inflammatory responses in skeletal muscle and mitochondria, both at rest and during exercise.

Oxidant-Dependent Sensitizing, Protective, and Mitigative Effects in X-Ray-Irradiated Pulmonary Endothelial Cells.

The primary response of proliferating bovine pulmonary artery endothelial cells (BPAECs) after X-ray irradiation [≤10 gray (Gy)] is shown to be transient cell-cycle arrest. Accompanying oxidant-linked functional changes within the mitochondria are readily measured, but increased autophagy is not. Radiation-induced apoptosis is negligible in this line-important because cells undergoing apoptosis release oxygen-derived species that can overwhelm/mask the radiation-associated species and their effects that we wish to investigate. Cells irradiated and cultured at 3% oxygen exhibited delayed cell-cycle arrest (6-8 hours after 10 Gy irradiation) compared with those maintained at 20% oxygen (2-4 hours after 10 Gy irradiation). At 3% oxygen, either only during or only after irradiation, results intermediate between 20% and 3% oxygen throughout were obtained. No variability in cell-cycle distribution was observed for unirradiated cells cultured under different prevailing oxygen levels. Mitochondrially localized manganese superoxide dismutase delayed the X-ray-induced cell-cycle changes when over-expressed in BPAEC, indicating superoxide to be one of the key oxygen-derived cytotoxic species involved in the radiobiological response. Also, the peroxynitrite biomarker 3-nitrotyrosine was elevated, whereas hydrogen peroxide levels were not. Lastly, the utility of the BPAEC for screening potential countermeasures to ionizing radiation is demonstrated with some quinoline derivatives. Three of the five compounds appeared mitigative, and all were protective. It is suggested that the oxidation-reduction chemistry of these compounds probably offers a reasonable explanation for their observed ameliorative properties. Furthermore, the results suggest a promising new direction in the search for lead compounds as countermeasures to the effects of ionizing radiation. SIGNIFICANCE STATEMENT: The primary radiological response of proliferating bovine pulmonary artery endothelial cells is cell-cycle arrest, starting soon after X-ray irradiation (1-10 Gy) at 20% O2 but delayed by 4 hours at systemic (3%) O2. Oxygen/superoxide is found to be radio-sensitizing in at least two distinct time windows, during and after the irradiation, with both responses antagonized by various hydroxyquinoline derivatives. Similar responses in many other cell lines are likely to be masked by elevated oxidants associated with apoptosis.

Effects of Corticosterone on Beta-Amyloid-Induced Cell Death in SH-SY5Y Cells.

Alzheimer's disease (AD) is a neurodegenerative disease characterized by neuronal cell death and memory impairment. Corticosterone (CORT) is a glucocorticoid hormone produced by the hypothalamic-pituitary-adrenal axis in response to a stressful condition. Excessive stress and high CORT levels are known to cause neurotoxicity and aggravate various diseases, whereas mild stress and low CORT levels exert beneficial actions under pathophysiological conditions. However, the effects of mild stress on AD have not been clearly elucidated yet. In this study, the effects of low (3 and 30 nM) CORT concentration on Aβ25-35-induced neurotoxicity in SH-SY5Y cells and underlying molecular mechanisms have been investigated. Cytotoxicity caused by Aβ25-35 was significantly inhibited by the low concentration of CORT treatment in the cells. Furthermore, CORT pretreatment significantly reduced Aβ25-35-mediated pro-apoptotic signals, such as increased Bim/Bcl-2 ratio and caspase-3 cleavage. Moreover, low concentration of CORT treatment inhibited the Aβ25-35-induced cyclooxygenase-2 and pro-inflammatory cytokine expressions, including tumor necrosis factor-α and interleukin-1β. Aβ25-35 resulted in intracellular accumulation of reactive oxygen species and lipid peroxidation, which were effectively reduced by the low CORT concentration. As a molecular mechanism, low CORT concentration activated the nuclear factor-erythroid 2-related factor 2, a redox-sensitive transcription factor mediating cellular defense and upregulating the expression of antioxidant enzymes, such as NAD(P)H:quinone oxidoreductase, glutamylcysteine synthetase, and manganese superoxide dismutase. These findings suggest that low CORT concentration exerts protective actions against Aβ25-35-induced neurotoxicity and might be used to treat and/or prevent AD.

Occurrence of Anthracnose Caused by Colletotrichum fructicola on Ficus hirta in Southern China.

Ficus hirta Vahl. is a Moraceae plant, named for its palm-like leaves. It is a widely used traditional medicinal material with definite curative effect. At the same time, it is also a commonly used soup material among the folk in South China. In March 2022, a serious leaf spot disease with symptoms similar to anthracnose was observed on F. hirta in several plantations in Qinzhou and Zhanjiang City of China, with an incidence of 32~65%. The early symptoms of infected leaves were small, round, yellow spots that further expanded into larger, brown, irregular, necrotic lesions surrounded by dark brown edges, which eventually led to leaf wilt. Twenty symptomatic leaves were collected from three plantations with a total area of about 10 hm2. Fragments (2×2 mm) from the 20 infected leaves were surface sterilized, plated on potato dextrose agar (PDA) and incubated at 28°C. After 3 days, isolates with similar cultural morphology were obtained and three representative isolates (WZMT-1, WZMT-3 and WZMT-8) were randomly selected for following study. The colonies by single-spore purification on PDA were initially cottony, pale white and became grayish green with age. The conidia were hyaline, abundant, cylindrical, with rounded ends, 14.4~18.2 μm×4.6~6.0 μm (av. 16.2 μm×5.4 μm, n=100). Conidiogenous cells hyaline, cylindrical or ampulliform, 6.2~22.7 μm × 2.7~5.0 μm (av. 12.9 μm×3.8 μm, n=50). Appressoria were brown to dark brown, ovoid to clavate, elliptical or irregular, 7.9~13.4 μm × 5.6~9.2 μm (av. 10.6 μm×7.9 μm, n=50). The morphology of the fungus resembled Colletotrichum fructicola (Prihastuti et al. 2009). For molecular identification, the internal transcribed spacer (ITS) regions, glyceraldehyde-3-phosphatedehydrogenase (GAPDH), actin (ACT), beta-tubulin 2 (TUB2), calmodulin (CAL), partial manganese superoxide dismutase (sod2), partial Apn2-Mat1-2 intergenic spacer and partial mating type (Mat1-2) (ApMat) genes were amplified from genomic DNA for the isolates using the primers described by Silva et al. (2012) and Weir et al. (2012). The sequences of the above seven loci of the three isolates (accession nos. OQ121661 to OQ121663 and OQ133400 to OQ133417) were obtained and showed over 99% identity with the existing sequences of ex-type culture ICMP 18581 of Colletotrichum fructicola (Weir et al. 2012). A multilocus phylogenetic analysis of the seven loci concatenated sequences using the maximum likelihood method revealed that the isolates belong to C. fructicola. To confirm pathogenicity, five 3-month-old potted plants were used for inoculation with each representative isolate. Tested plants were sprayed with 10 ml of a conidial suspension (1 × 108 conidia/ml) , and the controls plants were sprayed with sterile water. All the plants were incubated in a growth chamber at 26 ± 2°C with 95% relative humidity. After 10 days, typical lesions like those observed on the field plants appeared on all inoculated plants, while the control remained healthy. The same fungal pathogen was reisolated and the identity was confirmed by morphological characterization and molecular analysis, confirming Koch's postulates. The pathogen has been reported as the causal agent of anthracnose on a wide range of plant hosts worldwide (Marquez-Zequera et al. 2018; Horfer et al. 2021; Jiang et al. 2022; Li et al. 2023). To our knowledge, this is the first report of anthracnose on F. hirta caused by C. fructicola in southern China.

Role of oxidative stress in neurodegenerative disorders: a review of reactive oxygen species and prevention by antioxidants.

Neurological disorders include a variety of conditions, including Alzheimer's disease, motor neuron disease and Parkinson's disease, affecting longevity and quality of life, and their pathogenesis is associated with oxidative stress. Several of the chronic neurodegenerative pathologies of the CNS share some common features, such as oxidative stress, inflammation, synapse dysfunctions, protein misfolding and defective autophagia. Neuroinflammation can involve the activation of mast cells, contributing to oxidative stress, in addition to other sources of reactive oxygen species. Antioxidants can powerfully neutralize reactive oxygen species and free radicals, decreasing oxidative damage. Antioxidant genes, like the manganese superoxide dismutase enzyme, can undergo epigenetic changes that reduce their expression, thus increasing oxidative stress in tissue. Alternatively, DNA can be altered by free radical damage. The epigenetic landscape of these genes can change antioxidant function and may result in neurodegenerative disease. This imbalance of free radical production and antioxidant function increases the reactive oxygen species that cause cell damage in neurons and is often observed as an age-related event. Increased antioxidant expression in mice is protective against reactive oxygen species in neurons as is the exogenous supplementation of antioxidants. Manganese superoxide dismutase requires manganese for its enzymic function. Antioxidant therapy is considered for age-related neurodegenerative diseases, and a new mimetic of a manganese superoxide dismutase, avasopasem manganese, is described and suggested as a putative treatment to reduce the oxidative stress that causes neurodegenerative disease. The aim of this narrative review is to explore the evidence that oxidative stress causes neurodegenerative damage and the role of antioxidant genes in inhibiting reactive oxygen species damage. Can the neuronal environment of oxidative stress, causing neuroinflammation and neurodegeneration, be reduced or reversed?

Overexpression of manganese superoxide dismutase mitigates ACL injury-induced muscle atrophy, weakness and oxidative damage

Oxidative stress has been implicated in the etiology of skeletal muscle weakness following joint injury. We investigated longitudinal patient muscle samples following knee injury (anterior cruciate ligament tear). Following injury, transcriptomic analysis revealed downregulation of mitochondrial metabolism-related gene networks, which were supported by reduced mitochondrial respiratory flux rates. Additionally, enrichment of reactive oxygen species (ROS)-related pathways were upregulated in muscle following knee injury, and further investigation unveiled marked oxidative damage in a progressive manner following injury and surgical reconstruction. We then investigated whether antioxidant protection is effective in preventing muscle atrophy and weakness after knee injury in mice that overexpress Mn-superoxide dismutase (MnSOD+/−). MnSOD+/− mice showed attenuated oxidative damage, atrophy, and muscle weakness compared to wild type littermate controls following ACL transection surgery. Taken together, our results indicate that ROS-related damage is a causative mechanism of muscle dysfunction after knee injury, and that mitochondrial antioxidant protection may hold promise as a therapeutic target to prevent weakness and development of disability.

Manganese induces oxidative damage in the hippocampus by regulating the expression of oxidative stress-related genes via modulation of H3K18 acetylation.

Prolonged exposure to manganese (Mn) contributes to hippocampal Mn accumulation, which leads to neurodegenerative diseases called manganese poisoning. However, the underlying molecular mechanisms remain unclear and there are no ideal biomarkers. Oxidative stress is the essential mechanisms of Mn-related neurotoxicity. Furthermore, histone acetylation has been identified as being engaged in the onset and development of neurodegenerative diseases. Therefore, the work aims to understand the molecular mechanisms of oxidative damage in the hippocampus due to Mn exposure from the aspect of histone acetylation modification and to assess whether H3K18 acetylation (H3K18ac) modification level in peripheral blood reflect Mn-induced oxidative damage in the hippocampus. Here, we randomly divided 60 male rats into four groups and injected them intraperitoneally with sterile pure water and MnCl2 ⋅4H2 O (5, 10, and 15 mg/kg) for 16 weeks, 5 days a week, once a day. The data confirmed that Mn exposure down-regulated superoxide dismutase activity and glutathione level as well as up-regulated malondialdehyde level in the hippocampus and plasma, and that there was a positive correlation between these indicators in the hippocampus and plasma. Besides, we noted that Mn treatment upregulated H3K18ac modification levels in the hippocampus and peripheral blood and that H3K18ac modification levels correlated with oxidative stress. Further studies demonstrated that Mn treatment decreased the amounts of H3K18ac enrichment in the manganese superoxide dismutase (SOD2) and glutathione transferase omega 1 (GSTO1) gene promoter regions, contributing to oxidative damage in the hippocampus. In short, our results demonstrate that Mn induces oxidative damage in the hippocampus by inhibiting the expression of SOD2 and GSTO1 genes via modulation of H3K18ac. In assessing Mn-induced hippocampal neurotoxicity, oxidative damage in plasma may reflect hippocampal oxidative damage in Mn-exposed groups.