Regulation of pro-inflammatory responses by lipoxygenases via intracellular reactive oxygen species in vitro and in vivo

NADPH oxidase-dependent free radical generation and protein adduct formation in neutrophils

Neutrophils mediate the early innate immune response through extracellular traps comprising intracellular protein and DNA. These traps play a pivotal role in both immunity against invading pathogens and the development of immunopathological reactions through the production of reactive oxygen species (ROS). Proteins serve as the main target for ROS, resulting in the formation of protein adducts. Herein, we report that the superoxide anion radical (O2˙-) plays a vital role in neutrophil function through sequential events involving 5-lipoxygenase (5-LOX) and NADPH oxidase (NOX). More specifically, differences in NOX homologs expression were observed post-stimulation with PMA and LPS. Differentiation conditions and O2˙- generation were confirmed using flow cytometry. Immunoblotting analysis confirmed the time-dependent expression of NOX underlying its requirement and 5-LOX-mediated lipid peroxidation events in neutrophil function. Protein-malondialdehyde (MDA) adducts formed were detected using immunoblotting, and quercetin was evaluated for its ability to scavenge free radicals through electron paramagnetic resonance (EPR) spin-trapping spectroscopy and results were confirmed with blotting analysis. Free radical-mediated protein oxidation events influence neutrophil function and protein adducts formed serve as markers of neutrophil activation upon infection and inflammation. The study warrants further corroboration and the study of specific proteins involved in neutrophil activation and their role in inflammation.

Pharmacotherapies for the Treatment of Progressive Supranuclear Palsy: A Narrative Review

Progressive supranuclear palsy (PSP) is a neurodegenerative disorder resulting from the deposition of misfolded and neurotoxic forms of tau protein in specific areas of the midbrain, basal ganglia, and cortex. It is one of the most representative forms of tauopathy. PSP presents in several different phenotypic variations and is often accompanied by the development of concurrent neurodegenerative disorders. PSP is universally fatal, and effective disease-modifying therapies for PSP have not yet been identified. Several tau-targeting treatment modalities, including vaccines, monoclonal antibodies, and microtubule-stabilizing agents, have been investigated and have had no efficacy. The need to treat PSP and other tauopathies is critical, and many clinical trials investigating tau-targeted treatments are underway. In this review, the PubMed database was queried to collect information about preclinical and clinical research on PSP treatment. Additionally, the US National Library of Medicine's ClinicalTrials.gov website was queried to identify past and ongoing clinical trials relevant to PSP treatment. This narrative review summarizes our findings regarding these reports, which include potential disease-modifying drug trials, modifiable risk factor management, and symptom treatments.

Disaggregation-Activated pan-COX Imaging Agents for Human Soft tissue Sarcoma

Cancer stem cells are pivotal players in tumors initiation, growth, and metastasis. While several markers have been identified, there remain challenges particularly in heterogeneous malignancies like adult soft tissue sarcomas, where conventional markers are inherently overexpressed. Here, we designed BODIPY scaffold fluorescence probes (BD-IMC-1, BD-IMC-2) that activate via disaggregation targeting for cyclooxygenase (COX), a potential marker for CSCs in sarcoma in clinical pathology. Based on their structures, BD-IMC-1 showcased higher susceptibility to disaggregation compared to BD-IMC-2, consistent with their selective interaction with COX. Notably, the BD-IMC-1 revealed positive cooperativity binding to COX-2 at sub-micromolar ranges. Both probes showed significant fluorescence turn-on upon LPS or PMA triggered COX-2 upregulation in live RAW264.7, HeLa, and human sarcoma cell line (Saos-LM2) up to 2-fold increase with negligible toxicity. More importantly, the BD-IMC-1 demonstrated their practical imaging for COX-2 positive cells in paraffin-fixed human sarcoma tissue. Considering the fixed tissues are most practiced pathological sample, our finding suggests a potential of disaggregation activated chemosensor for clinical applications.

NADPH Oxidases: From Molecular Mechanisms to Current Inhibitors

NADPH oxidases (NOXs) form a family of electron-transporting membrane enzymes whose main function is reactive oxygen species (ROS) generation. Strong evidence suggests that ROS produced by NOX enzymes are major contributors to oxidative damage under pathologic conditions. Therefore, blocking the undesirable actions of these enzymes is a therapeutic strategy for treating various pathological disorders, such as cardiovascular diseases, inflammation, and cancer. To date, identification of selective NOX inhibitors is quite challenging, precluding a pharmacologic demonstration of NOX as therapeutic targets in vivo. The aim of this Perspective is to furnish an updated outlook about the small-molecule NOX inhibitors described over the last two decades. Structures, activities, and in vitro/in vivo specificity are discussed, as well as the main biological assays used.

Sex differences in neuroimmunoendocrine communication. Involvement on longevity

Endocrine, nervous, and immune systems work coordinately to maintain the global homeostasis of the organism. They show sex differences in their functions that, in turn, contribute to sex differences beyond reproductive function. Females display a better control of the energetic metabolism and improved neuroprotection and have more antioxidant defenses and a better inflammatory status than males, which is associated with a more robust immune response than that of males. These differences are present from the early stages of life, being more relevant in adulthood and influencing the aging trajectory in each sex and may contribute to the different life lifespan between sexes.

In Vitro and In Silico Evaluation of the Antimicrobial and Antioxidant Potential of Thymus pulegioides Essential Oil

The study was designed to analyze and evaluate the antioxidant and antibacterial properties of the essential oils of Thymus pulegioides L. grown in Western Romania. Thymus pulegioides L. essential oil (TPEO) was extracted by steam distillation (0.71% v/w) using a Craveiro-type apparatus. GC-MS investigation of the TPEO identified 39 different compounds, representing 98.46% of total oil. Findings revealed that thymol (22.89%) is the main compound of TPEO, followed by para-cymene (14.57%), thymol methyl ether (11.19%), isothymol methyl ether (10.45%), and beta-bisabolene (9.53%). The oil exhibits good antibacterial effects; C. parapsilosis, C. albicans, S. pyogenes, and S. aureus were the most sensitive strains. The antioxidant activity of TPEO was evaluated by peroxide and thiobarbituric acid value, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), [2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium] (ABTS) radical scavenging assay, and beta-carotene/linoleic acid bleaching testing. The antioxidative data recorded reveal, for the first time, that TPEO inhibits primary and secondary oxidation products, in some particular conditions, better than butylated hydroxyanisole (BHA) with significant statistical difference (p < 0.05). Moreover, TPEO antioxidant capabilities in DPPH and ABTS assays outperformed alpha-tocopherol (p < 0.001) and delta-tocopherol (p < 0.001). Molecular docking analysis revealed that one potential target correlated with the TPEO antimicrobial activity was d-alanine-d-alanine ligase (DDl). The best scoring ligand, linalyl anthranilate, shared highly similar binding patterns with the DDl native inhibitor. Furthermore, molecular docking analysis also showed that the main constituents of TPEO are good candidates for xanthine oxidase and lipoxygenase inhibition, making the essential oil a valuable source for protein-targeted antioxidant compounds. Consequently, TPEO may represent a new potential source of antioxidant and antibacterial agents with applicability in the food and pharmaceutic industries.

Reactive Oxygen Species Scavenging Nanomedicine for the Treatment of Ischemic Heart Disease

Ischemic heart disease (IHD) is the leading cause of disability and mortality worldwide. Reactive oxygen species (ROS) have been shown to play key roles in the progression of diabetes, hypertension, and hypercholesterolemia, which are independent risk factors that lead to atherosclerosis and the development of IHD. Engineered biomaterial-based nanomedicines are under extensive investigation and exploration, serving as smart and multifunctional nanocarriers for synergistic therapeutic effect. Capitalizing on cell/molecule-targeting drug delivery, nanomedicines present enhanced specificity and safety with favorable pharmacokinetics and pharmacodynamics. Herein, the roles of ROS in both IHD and its risk factors are discussed, highlighting cardiovascular medications that have antioxidant properties, and summarizing the advantages, properties, and recent achievements of nanomedicines that have ROS scavenging capacity for the treatment of diabetes, hypertension, hypercholesterolemia, atherosclerosis, ischemia/reperfusion, and myocardial infarction. Finally, the current challenges of nanomedicines for ROS-scavenging treatment of IHD and possible future directions are discussed from a clinical perspective.

Toxoplasma gondii Infection Decreases Intestinal 5-Lipoxygenase Expression, while Exogenous LTB4 Controls Parasite Growth

5-Lipoxygenase (5-LO) is an enzyme required for the production of leukotrienes and lipoxins and interferes with parasitic infections. In vitro, Toxoplasma gondii inhibits leukotriene B₄ (LTB₄) production, and mice deficient in 5-LO are highly susceptible to infection. The aim of this study was to investigate the effects of the pharmacological inhibition of the 5-LO pathway and exogenous LTB₄ supplementation during experimental toxoplasmosis. For this purpose, susceptible C57BL/6 mice were orally infected with T. gondii and treated with LTB₄ or MK886 (a selective leukotriene inhibitor through inhibition of 5-LO-activating protein [FLAP]). The parasitism, histology, and immunological parameters were analyzed. The infection decreased 5-LO expression in the small intestine, and treatment with MK886 reinforced this reduction during infection; in addition, MK886-treated infected mice presented higher intestinal parasitism, which was associated with lower local interleukin-6 (IL-6), interferon gamma (IFN-γ), and tumor necrosis factor (TNF) production. In contrast, treatment with LTB₄ controlled parasite replication in the small intestine, liver, and lung and decreased pulmonary pathology. Interestingly, treatment with LTB₄ also preserved the number of Paneth cells and increased α-defensins expression and IgA levels in the small intestine of infected mice. Altogether, these data demonstrated that T. gondii infection is associated with a decrease in 5-LO expression, and on the other hand, treatment with the 5-LO pathway product LTB₄ resulted in better control of parasite growth in the organs, adding to the knowledge about the pathogenesis of T. gondii infection.

Flavonoids Enhance Lipofection Efficiency and Ameliorate Cytotoxicity in Colon26 and HepG2 Cells via Oxidative Stress Regulation

The generation of reactive oxygen species (ROS) can affect cationic liposome-mediated transfection. In this study, we focused on a specific class of antioxidants, flavonoids, to investigate the transfection efficiency using cationic liposome/plasmid DNA complexes (lipoplexes) in 2D and 3D cultures of Colon26 and HepG2 cells, respectively. All tested flavonoids enhanced the transfection efficiency in 2D Colon26 and HepG2 cells. Among the tested flavonoids, 25 µM quercetin showed the highest promotion effect of 8.4- and 7.6-folds in 2D Colon26 and HepG2 cells, respectively. Transfection was also performed in 3D cultures of Colon26 and HepG2 cells using lipoplexes with quercetin. Quercetin (12.5 µM) showed the highest transfection efficiency at all transfection timings in 3D Colon26 and HepG2 cells with increased cell viability. Flow cytometry revealed that quercetin treatment reduced the population of gene expression-negative cells with high ROS levels and increased the number of gene expression-positive cells with low ROS levels in HepG2 cells. Information from this study can be valuable to develop strategies to promote transfection efficiency and attenuate cytotoxicity using lipoplexes.

The Dangerous Liaisons in the Oxidative Stress Response to Leishmania Infection

Leishmania parasites preferentially invade macrophages, the professional phagocytic cells, at the site of infection. Macrophages play conflicting roles in Leishmania infection either by the destruction of internalized parasites or by providing a safe shelter for parasite replication. In response to invading pathogens, however, macrophages induce an oxidative burst as a mechanism of defense to promote pathogen removal and contribute to signaling pathways involving inflammation and the immune response. Thus, oxidative stress plays a dual role in infection whereby free radicals protect against invading pathogens but can also cause inflammation resulting in tissue damage. The induced oxidative stress in parasitic infections triggers the activation in the host of the antioxidant response to counteract the damaging oxidative burst. Consequently, macrophages are crucial for disease progression or control. The ultimate outcome depends on dangerous liaisons between the infecting Leishmania spp. and the type and strength of the host immune response.

Anti-Inflammatory Effects of (9Z,11E)-13-Oxooctadeca-9,11-dienoic Acid (13-KODE) Derived from Salicornia herbacea L. on Lipopolysaccharide-Stimulated Murine Macrophage via NF-kB and MAPK Inhibition and Nrf2/HO-1 Signaling Activation

Glasswort (Salicornia herbacea L.) is a halophyte that exhibits antioxidant and antidiabetic effects. Only a few studies have been conducted on its antioxidant effects. Here, we isolated an antioxidant using an activity-based purification method, and the resulting compound was identified as (9Z,11E)-13-Oxooctadeca-9,11-dienoic acid (13-KODE). We investigated its ability to suppress inflammatory responses and the molecular mechanisms underlying these abilities using lipopolysaccharide-stimulated RAW 264.7 macrophage cells. We studied the anti-inflammatory effects of 13-KODE derived from S. herbacea L on RAW 264.7 macrophages. 13-KODE inhibited lipopolysaccharide (LPS)-induced nitric oxide (NO) production by suppressing inducible NO synthase and suppressed LPS-induced tumor necrosis factor and interleukin-1β expression in RAW 264.7 macrophages. LPS-mediated nuclear localization of NF-κB and mitogen-activated protein kinase activation were inhibited by 13-KODE. 13-KODE significantly reduced LPS-induced production of reactive oxygen species and increased the expression of nuclear factor erythroid-2 like 2 (Nfe2I2) and heme oxygenase 1. Overall, our results indicate that 13-KODE may have potential for treating inflammation.

Exploring nordihydroguaretic acid (NDGA) as a plausible neurotherapeutic in the experimental paradigm of autism spectrum disorders targeting nitric oxide pathway

The present study investigates the neuro-protective ability of nordihydroguaretic acid (NDGA) in the experimental paradigm of autism spectrum disorders (ASD) and further decipher the nitric oxide pathway's role in its proposed action. An intracerebroventricular infusion of 4 μl of 1 M PPA was given in the lateral ventricle's anterior region to induce autism-like phenotype in male rats. Oral administration of NDGA (5, 10 & 15 mg/kg) was initiated from the 3^rd day lasting till the 28th day. L-NAME (50 mg/kg) and L-Arginine (800 mg/kg) were also given individually and combined to explore NDGA's ability to act via the nitric oxide pathway. Behavior tests for sociability, stereotypy, anxiety, depression, novelty, repetitive and perseverative behavior were carried out between the 14th and 28th day. On the 29th day, animals were sacrificed, and mitochondrial complexes and oxidative stress parameters were evaluated. We also estimated the levels of neuroinflammatory and apoptotic markers such as TNF-α, IL-6, NF-κB, IFN-γ, HSP-70, and caspase-3. To assess the involvement of the nitric oxide pathway, levels of iNOS and homocysteine were estimated. Treatment with NDGA significantly restored behavioral, biochemical, neurological, and molecular deficits. Hence, NDGA can be used as a neurotherapeutic agent in ASD. Targeting nitric oxide pathway mediated oxidative & nitrosative stress responsible for behavioral, biochemical, and molecular alterations via modulating nitric oxide pathway. The evaluation of iNOS and homocysteine levels conclusively establishes the nitric oxide pathway's role in causing behavioral, biochemical & molecular deficits and NDGA's beneficial effect in restoring these alterations.

ROS/TNF-α Crosstalk Triggers the Expression of IL-8 and MCP-1 in Human Monocytic THP-1 Cells via the NF-κB and ERK1/2 Mediated Signaling

IL-8/MCP-1 act as neutrophil/monocyte chemoattractants, respectively. Oxidative stress emerges as a key player in the pathophysiology of obesity. However, it remains unclear whether the TNF-α/oxidative stress interplay can trigger IL-8/MCP-1 expression and, if so, by which mechanism(s). IL-8/MCP-1 adipose expression was detected in lean, overweight, and obese individuals, 15 each, using immunohistochemistry. To detect the role of reactive oxygen species (ROS)/TNF-α synergy as a chemokine driver, THP-1 cells were stimulated with TNF-α, with/without H₂O₂ or hypoxia. Target gene expression was measured by qRT-PCR, proteins by flow cytometry/confocal microscopy, ROS by DCFH-DA assay, and signaling pathways by immunoblotting. IL-8/MCP-1 adipose expression was significantly higher in obese/overweight. Furthermore, IL-8/MCP-1 mRNA/protein was amplified in monocytic cells following stimulation with TNF-α in the presence of H₂O₂ or hypoxia (p ˂ 0.0001). Synergistic chemokine upregulation was related to the ROS levels, while pre-treatments with NAC suppressed this chemokine elevation (p ≤ 0.01). The ROS/TNF-α crosstalk involved upregulation of CHOP, ERN1, HIF1A, and NF-κB/ERK-1,2 mediated signaling. In conclusion, IL-8/MCP-1 adipose expression is elevated in obesity. Mechanistically, ROS/TNF-α crosstalk may drive expression of these chemokines in monocytic cells by inducing ER stress, HIF1A stabilization, and signaling via NF-κB/ERK-1,2. NAC had inhibitory effect on oxidative stress-driven IL-8/MCP-1 expression, which may have therapeutic significance regarding meta-inflammation.

Reactive Oxygen Species and Endothelial Ca2+ Signaling: Brothers in Arms or Partners in Crime?

An increase in intracellular Ca²⁺ concentration ([Ca²⁺]_i) controls virtually all endothelial cell functions and is, therefore, crucial to maintain cardiovascular homeostasis. An aberrant elevation in endothelial can indeed lead to severe cardiovascular disorders. Likewise, moderate amounts of reactive oxygen species (ROS) induce intracellular Ca²⁺ signals to regulate vascular functions, while excessive ROS production may exploit dysregulated Ca²⁺ dynamics to induce endothelial injury. Herein, we survey how ROS induce endothelial Ca²⁺ signals to regulate vascular functions and, vice versa, how aberrant ROS generation may exploit the Ca²⁺ handling machinery to promote endothelial dysfunction. ROS elicit endothelial Ca²⁺ signals by regulating inositol-1,4,5-trisphosphate receptors, sarco-endoplasmic reticulum Ca²⁺-ATPase 2B, two-pore channels, store-operated Ca²⁺ entry (SOCE), and multiple isoforms of transient receptor potential (TRP) channels. ROS-induced endothelial Ca²⁺ signals regulate endothelial permeability, angiogenesis, and generation of vasorelaxing mediators and can be exploited to induce therapeutic angiogenesis, rescue neurovascular coupling, and induce cancer regression. However, an increase in endothelial [Ca²⁺]_i induced by aberrant ROS formation may result in endothelial dysfunction, inflammatory diseases, metabolic disorders, and pulmonary artery hypertension. This information could pave the way to design alternative treatments to interfere with the life-threatening interconnection between endothelial ROS and Ca²⁺ signaling under multiple pathological conditions.

Novel Therapies for Parkinsonian Syndromes-Recent Progress and Future Perspectives

Background: Atypical parkinsonian syndromes are rare, fatal neurodegenerative diseases associated with abnormal protein accumulation in the brain. Examples of these syndromes include progressive supranuclear palsy, multiple system atrophy, and corticobasal degeneration. A common clinical feature in parkinsonism is a limited improvement with levodopa. So far, there are no disease-modifying treatments to address these conditions, and therapy is only limited to the alleviation of symptoms. Diagnosis is devastating for patients, as prognosis is extremely poor, and the disease tends to progress rapidly. Currently, potential causes and neuropathological mechanisms involved in these diseases are being widely investigated. Objectives: The goal of this review is to summarize recent advances and gather emerging disease-modifying therapies that could slow the progression of atypical parkinsonian syndromes. Methods: PubMed and Google Scholar databases were searched regarding novel perspectives for atypical parkinsonism treatment. The following medical subject headings were used: "atypical parkinsonian syndromes-therapy," "treatment of atypical parkinsonian syndromes," "atypical parkinsonian syndromes-clinical trial," "therapy of tauopathy," "alpha-synucleinopathy treatment," "PSP therapy/treatment," "CBD therapy/treatment," "MSA therapy/treatment," and "atypical parkinsonian syndromes-disease modifying." All search results were manually reviewed prior to inclusion in this review. Results: Neuroinflammation, mitochondrial dysfunction, microglia activation, proteasomal impairment, and oxidative stress play a role in the neurodegenerative process. Ongoing studies and clinical trials target these components in order to suppress toxic protein accumulation. Various approaches such as stem cell therapy, anti-aggregation/anti-phosphorylation agent administration, or usage of active and passive immunization appear to have promising results. Conclusion: Presently, disease-modifying strategies for atypical parkinsonian syndromes are being actively explored, with encouraging preliminary results. This leads to an assumption that developing accurate, safe, and progression-halting treatment is not far off. Nevertheless, the further investigation remains necessary.

5-Hydroxymaltol Derived from Beetroot Juice through Lactobacillus Fermentation Suppresses Inflammatory Effect and Oxidant Stress via Regulating NF-kB, MAPKs Pathway and NRF2/HO-1 Expression

Inflammation is the first response of the immune system against bacterial pathogens. This study isolated and examined an antioxidant derived from Lactobacillus fermentation products using cultured media with 1% beet powder. The antioxidant activity of the beet culture media was significantly high. Antioxidant activity-guided purification and repeated sample isolation yielded an isolated compound, which was identified as 5-hydoxymaltol using nuclear magnetic resonance spectrometry. We examined the mechanism of its protective effect on lipopolysaccharide (LPS)-induced inflammation of macrophages. 5-Hydroxymaltol suppressed nitric oxide (NO) production in LPS-stimulated RAW 264.7 cells. It also suppressed tumor necrosis factor α (TNF-α), interleukin (IL)-1β, and inducible nitric oxide synthase (iNOS) in the messenger RNA and protein levels in LPS-treated RAW 264.7 cells. Moreover, it suppressed LPS-induced nuclear translocation of NF-κB (p65) and mitogen-activated protein kinase activation. Furthermore, 5-hydroxymaltol reduced LPS-induced reactive oxygen species (ROS) production as well as increased nuclear factor erythroid 2-related factor 2 and heme oxygenase 1 expression. Overall, this study found that 5-hydroxymaltol has anti-inflammatory activities in LPS-stimulated RAW 264.7 macrophage cells based on its inhibition of pro-inflammatory cytokine production depending on the nuclear factor κB signaling pathway, inhibition of LPS-induced reactive oxygen species production, inhibition of LPS-induced mitogen-activated protein kinase induction, and induction of the nuclear factor erythroid 2-related factor 2/heme oxygenase 1 signaling pathway. Our data showed that 5-hydroxymaltol may be an effective compound for treating inflammation-mediated diseases.

Protective effects and mechanism of action of ruscogenin in a mouse model of ovalbumin-induced asthma

OBJECTIVE

Ruscogenin is a natural product exhibiting anti-inflammatory, antioxidant, and anti-apoptotic effects; however, its effectiveness for asthma management has not yet been reported. The aim of this study was to explore the role of ruscogenin in airway inflammation and apoptosis in asthma.

METHODS

In vivo, female 6- to 8-week-old CL57 mice were sensitized to ovalbumin and challenged intranasally for 7 days. One group was gavaged with ruscogenin before ovalbumin challenge. At the end of the challenge period, airway hyperresponsiveness and airway inflammation were evaluated. Enzyme-linked immunosorbent assay was used to estimate the oxidative stress levels. A terminal deoxynucleotidyl transferase dUDP nick-end labeling assay was used to determine the extent of apoptosis. Immunohistochemistry and western blotting were performed to examine VDAC1 expression. In vitro, human bronchial epithelial (HBE) cells were treated with H₂O₂, ruscogenin, or disulfonate salt, and flow cytometry was used to calculate the apoptosis ratio and detect mitochondrial calcium levels.

RESULTS

In vivo, ruscogenin improved airway hyperresponsiveness and airway inflammation, while reducing oxidative stress, the apoptosis ratio and VDAC1 expression in asthmatic lungs. In vitro, ruscogenin attenuated apoptosis in HBE cells by decreasing the levels of VDAC1 expression and mitochondrial calcium.

CONCLUSION

Ruscogenin reduced oxidative stress and apoptosis in the airway epithelium by inhibiting VDAC1 expression and mitochondrial handling of calcium.

Antioxidant Effects of Schisandra chinensis Fruits and Their Active Constituents

Schisandra chinensis Turcz. (Baill.) fruits, their extracts, and bioactive compounds are used in alternative medicine as adaptogens and ergogens protecting against numerous neurological, cardiovascular, gastrointestinal, liver, and skin disorders. S. chinensis fruit extracts and their active compounds are potent antioxidants and mitoprotectors exerting anti-inflammatory, antiviral, anticancer, and anti-aging effects. S. chinensis polyphenolic compounds-flavonoids, phenolic acids and the major constituents dibenzocyclooctadiene lignans are responsible for the S. chinensis antioxidant activities. This review will focus on the direct and indirect antioxidant effects of S. chinensis fruit extract and its bioactive compounds in the cells during normal and pathological conditions.

Functions of ROS in Macrophages and Antimicrobial Immunity

Reactive oxygen species (ROS) are a chemically defined group of reactive molecules derived from molecular oxygen. ROS are involved in a plethora of processes in cells in all domains of life, ranging from bacteria, plants and animals, including humans. The importance of ROS for macrophage-mediated immunity is unquestioned. Their functions comprise direct antimicrobial activity against bacteria and parasites as well as redox-regulation of immune signaling and induction of inflammasome activation. However, only a few studies have performed in-depth ROS analyses and even fewer have identified the precise redox-regulated target molecules. In this review, we will give a brief introduction to ROS and their sources in macrophages, summarize the versatile roles of ROS in direct and indirect antimicrobial immune defense, and provide an overview of commonly used ROS probes, scavengers and inhibitors.

Why do sexes differ in lifespan extension? Sex-specific pathways of aging and underlying mechanisms for dimorphic responses

Males and females typically have different lifespans and frequently differ in their responses to anti-aging interventions. These sex-specific responses are documented in mice and Drosophila species, in addition to other organisms where interventions have been tested. While the prevalence of sex-specific responses to anti-aging interventions is now recognised, the underlying causes remain poorly understood. This review first summarises the main pathways and interventions that lead to sex-specific lifespan responses, including the growth-hormone/insulin-like growth factor 1 (GH-IGF1) axis, mechanistic target of rapamycin (mTOR) signalling, and nutritional and pharmacological interventions. After summarising current evidence, several different potential causes for sex-specific responses are discussed. These include sex-differences in xenobiotic metabolism, differing disease susceptibility, sex-specific hormone production and chromosomes, and the relative importance of different signalling pathways in the control of male and female life-history. Understanding why sex-differences in lifespan-extension occur should provide a greater understanding of the mechanisms that regulate the aging process in each sex, and will be crucial for understanding the full implications of these treatments if they are translated to humans.

BPA Differentially Regulates NPY Expression in Hypothalamic Neurons Through a Mechanism Involving Oxidative Stress

Bisphenol A (BPA), a ubiquitous endocrine-disrupting chemical, interferes with reproduction and is also considered an obesogen. The neuropeptide Y (NPY) neurons of the hypothalamus control both food intake and reproduction and have emerged as potential targets of BPA. These functionally diverse subpopulations of NPY neurons are differentially regulated by peripheral signals, such as estrogen and leptin. Whether BPA also differentially alters Npy expression in subpopulations of NPY neurons, contributing to BPA-induced endocrine dysfunction is unclear. We investigated the response of 6 immortalized hypothalamic NPY-expressing cell lines to BPA treatment. BPA upregulated Npy mRNA expression in 4 cell lines (mHypoA-59, mHypoE-41, mHypoA-2/12, mHypoE-42), and downregulated Npy in 2 lines (mHypoE-46, mHypoE-44). This differential expression of Npy occurred concurrently with differential expression of estrogen receptor mRNA levels. Inhibition of G-protein coupled estrogen receptor GPR30 or estrogen receptor β prevented the BPA-mediated decrease in Npy, whereas inhibition of energy sensor 5' adenosine monophosphate-activated protein kinase (AMPK) with compound C prevented BPA-induced increase in Npy. BPA also altered neuroinflammatory and oxidative stress markers in both mHypoA-59 and mHypoE-46 cell lines despite the differential regulation of Npy. Remarkably, treatment with BPA in an antioxidant-rich media, Neurobasal A (NBA), or with reactive oxygen species scavenger tauroursodeoxycholic acid mitigated the BPA-induced increase and decrease in Npy. Furthermore, 2 antioxidant species from NBA-N-acetylcysteine and vitamin B6-diminished the induction of Npy in the mHypoA-59 cells, demonstrating these supplements can counteract BPA-induced dysregulation in certain subpopulations. Overall, these results illustrate the differential regulation of Npy by BPA in neuronal subpopulations, and point to oxidative stress as a pathway that can be targeted to block BPA-induced Npy dysregulation in hypothalamic neurons.

Characterization and Localization of Calb2 in Both the Testis and Ovary of the Japanese Flounder (Paralichthys olivaceus)

Simple Summary

Calretinin (CALB2), which is a Ca²⁺-binding protein, plays a known pivotal role in the neural system in vertebrates. The role of CALB2 in mammalian gonads has been gradually recognized; however, little information on the function of CALB2 in fish gonads has been reported. Therefore, we firstly identified the calb2 gene in Paralichthys olivaceus (P. olivaceus), and then investigated its tissue distribution and localization in the gonads by real-time PCR, western blotting, and immunohistochemistry. The P. olivaceus calb2 mRNA was relatively highly expressed in both the testis and ovary. The CALB2 protein is located in Leydig cells of the testis and ovarian germ epithelial cells in P. olivaceus. This study provides a basis for further explorations on the function and regulation mechanism of calb2 in fish gonads.

Abstract

Although its function in mammalian gonads has been gradually recognized, the expression and function of calretinin (CALB2)—a Ca²⁺-binding protein—in the testis and ovary of fish are still unclear. Here, we identified the cDNA sequences of calb2 in Paralichthys olivaceus (P. olivaceus); analyzed its gene structure and phylogenetic and syntenic relationship by bioinformatics; and investigated its tissue distribution and localization in the gonads by real-time PCR, western blotting, and immunohistochemistry. The P. olivaceuscalb2 gene has 11 exons and 10 introns, and the full-length cDNA is 1457 bp, including an open reading frame (ORF) of 816 bp encoding 271 amino acids. The CALB2 of P. olivaceus has a higher homology with Lates calcarifer (99%) compared with other species. The conserved synteny of calb2 neighboring gene loci was also detected in fish. Real-time PCR showed that the expression of calb2 mRNA is abundant not only in the brain, but also in the gonads, and exhibits a higher expression in the testis than in the ovary. Western blotting indicated that the CALB2 protein has a higher expression in the testis compared with the ovary. Immunohistochemistry demonstrated that the CALB2 protein appears in Leydig cells and the ovarian germ epithelium. These results reveal that calb2 plays an important role in the gonads of P. olivaceus.

Nordihydroguaiaretic acid reduces secondary organ injury in septic rats after cecal ligation and puncture

BACKGROUND

Nordihydroguaiaretic acid (NDGA) is a plant extract that has been shown to act as a free radical scavenger and pluripotent inhibitor of pro-inflammatory cytokines, two major cellular processes involved in the pathophysiology of sepsis. We investigated whether NDGA would improve markers of organ injury as well as survival in a rodent model of sepsis.

METHODS

Abdominal sepsis was induced by cecal ligation and double puncture (CLP) in male Sprague-Dawley rats. NDGA was administered either at the time of injury (pre-) or 6 hours later (post-treatment). A sham surgery group and a vehicle only group were also followed as controls. Blood and lung tissue were collected 24 h after CLP. Lung tissue was used for histopathologic analysis and to measure pulmonary edema. Arterial oxygenation was measured directly to generate PaO2/FiO2, and markers of renal injury (blood urea nitrogen), liver injury (alanine aminotransferase), and tissue hypoxia (lactate) were measured. In a separate set of animals consisting of the same treatment groups, animals were followed for up to 36 hours for survival.

RESULTS

NDGA pre-treatment resulted in improved oxygenation, less lung edema, lower lactate, lower BUN, and reduced histologic lung injury. NDGA post-treatment resulted in less lung edema, lower lactate, lower BUN, and less histologic lung injury, but did not significantly change oxygenation. None of the NDGA treatment groups statistically affected ALT or creatinine. NDGA pre-treatment showed improved survival compared with control CLP animals at 36 hours, while post-treatment did not.

CONCLUSIONS

NDGA represents a novel pleiotropic anti-inflammatory agent with potential clinical utility for modulation of organ injury secondary to sepsis.

Garcinol Exhibits Anti-Neoplastic Effects by Targeting Diverse Oncogenic Factors in Tumor Cells

Garcinol, a polyisoprenylated benzophenone, is the medicinal component obtained from fruits and leaves of Garcinia indica (G. indica) and has traditionally been extensively used for its antioxidant and anti-inflammatory properties. In addition, it has been also been experimentally illustrated to elicit anti-cancer properties. Several in vitro and in vivo studies have illustrated the potential therapeutic efficiency of garcinol in management of different malignancies. It mainly acts as an inhibitor of cellular processes via regulation of transcription factors NF-κB and JAK/STAT3 in tumor cells and have been demonstrated to effectively inhibit growth of malignant cell population. Numerous studies have highlighted the anti-neoplastic potential of garcinol in different oncological transformations including colon cancer, breast cancer, prostate cancer, head and neck cancer, hepatocellular carcinoma, etc. However, use of garcinol is still in its pre-clinical stage and this is mainly attributed to the limitations of conclusive evaluation of pharmacological parameters. This necessitates evaluation of garcinol pharmacokinetics to precisely identify an appropriate dose and route of administration, tolerability, and potency under physiological conditions along with characterization of a therapeutic index. Hence, the research is presently ongoing in the dimension of exploring the precise metabolic mechanism of garcinol. Despite various lacunae, garcinol has presented with promising anti-cancer effects. Hence, this review is motivated by the constantly emerging and promising positive anti-cancerous effects of garcinol. This review is the first effort to summarize the mechanism of action of garcinol in modulation of anti-cancer effect via regulation of different cellular processes.

Larrea divaricata Cav. aqueous extract and nordihydroguariaretic acid modulate oxidative stress in submandibular glands of diabetic rats: a buccal protective in diabetes

Background

Oxidative stress is an imbalance between the levels of reactive oxygen species (ROS), reactive nitrogen species (RNS) and endogenous antioxidants. The aetiology and pathogenesis of several oral diseases are attributed to this process. The antioxidant enzymes secreted in the saliva by submandibular glands maintain oral health through the scavenging of ROS. The objective of this work was to study the capacity of an aqueous extract of L. divaricata (AE), and its majority compound, nordihydroguariaretic acid (NDGA), to modulate the pro-oxidant/antioxidant status in submandibular glands in a model of oxidative stress induced by streptozotocin (STZ) in rats.

Methods

To induce oxidative stress with STZ, a group of animals was treated i.p. with 1 X PBS (control group) and other group was injected i.p. once with STZ (60 mg/kg). Ten days after the treatment, blood samples were taken from the tail vain to determine the glucose levels. Animals with glucose values ≥300 mg/ml were selected.

The submandibular glands of control and STZ treated animals were incubated with either the AE (500 μg/ml) or with NDGA (1.5 μg/ml), and the content of malondialdehyde (MDA), protein carbonyl groups, ROS and RNS, and the activity and expression of peroxidase (Px), superoxide dismutase (SOD) and inducible nitric oxide synthase (iNOS) were assayed.

Results

AE decreased the levels of MDA (^##P < 0.01) and protein carbonyl groups (^#P < 0.05), and modulated the levels of ROS such as hydrogen peroxide (H₂O₂)(^##P < 0.01), superoxide anion (O₂^.-) (^#P < 0.05) and nitric oxide (NO) (^#P < 0.05) in relation to the modulation of Px and iNOS expression. NDGA was found to be involved in these effects.

Conclusions

The antioxidant activity of the AE in the submandibular glands would allow the maintenance of the antioxidant pool to prevent oral oxidative diseases.

Paradigm shift - Metabolic transformation of docosahexaenoic and eicosapentaenoic acids to bioactives exemplify the promise of fatty acid drug discovery

Fatty acid drug discovery (FADD) is defined as the identification of novel, specialized bioactive mediators that are derived from fatty acids and have precise pharmacological/therapeutic potential. A number of reports indicate that dietary intake of omega-3 fatty acids and limited intake of omega-6 promotes overall health benefits. In 1929, Burr and Burr indicated the significant role of essential fatty acids for survival and functional health of many organs. In reference to specific dietary benefits of differential omega-3 fatty acids, docosahexaenoic and eicosapentaenoic acids (DHA and EPA) are transformed to monohydroxy, dihydroxy, trihydroxy, and other complex mediators during infection, injury, and exercise to resolve inflammation. The presented FADD approach describes the metabolic transformation of DHA and EPA in response to injury, infection, and exercise to govern uncontrolled inflammation. Metabolic transformation of DHA and EPA into a number of pro-resolving molecules exemplifies a novel, inexpensive approach compared to traditional, expensive drug discovery. DHA and EPA have been recommended for prevention of cardiovascular disease since 1970. Therefore, the FADD approach is relevant to cardiovascular disease and resolution of inflammation in many injury models. Future research demands identification of novel action targets, receptors for biomolecules, mechanism(s), and drug-interactions with resolvins in order to maintain homeostasis.

Nordihydroguaiaretic acid can suppress progression of experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is a poorly understood disease mechanistically. MOG35-55 peptide induced experimental autoimmune encephalomyelitis (EAE) is a broadly used model to study MS. Using this model we have earlier shown that the antioxidant tempol or the small molecule inhibitor of p38 SB203580 can effectively prevent EAE progression. This effect was mediated by means of regulating immune inflammation, signaling by the p38MAPK-SGK1 pathway, and oxidative stress. However, there is a need to test drugs that can be used in pharmacological intervention of EAE. Given that nordihydroguaiaretic Acid (NDGA) has been shown to possess anti-oxidant activity and capacity of antagonizing autoimmune inflammation, we tested the effect of NDGA in ameliorating EAE in the current study. NDGA showed significant beneficial effect against EAE with both anti-inflammation and antioxidant activity. NDGA could weaken the immune inflammation at least partly by inhibiting the oxidant stress-p38MAPK-SGK1 pathway representing a target for putative pharmacological intervention. © 2018 IUBMB Life, 70(5):432-436, 2018.

Reactive Oxygen Species, Biomarkers of Microvascular Maturation and Alveolarization, and Antioxidants in Oxidative Lung Injury

The lungs of extremely low gestational age neonates (ELGANs) are deficient in pulmonary surfactant and are incapable of efficient gas exchange necessary for successful transition from a hypoxic intrauterine environment to ambient air. To improve gas exchange and survival, ELGANs often receive supplemental oxygen with mechanical ventilation which disrupts normal lung developmental processes, including microvascular maturation and alveolarization. Factors that regulate these developmental processes include vascular endothelial growth factor and matrix metalloproteinases, both of which are influenced by generation of oxygen byproducts, or reactive oxygen species (ROS). ELGANs are also deficient in antioxidants necessary to scavenge excessive ROS. Thus, the accumulation of ROS in the preterm lungs exposed to prolonged hyperoxia, results in inflammation and development of bronchopulmonary dysplasia (BPD), a form of chronic lung disease (CLD). Despite advances in neonatal care, BPD/CLD remains a major cause of neonatal morbidity and mortality. The underlying mechanisms are not completely understood, and the benefits of current therapeutic interventions are limited. The association between ROS and biomarkers of microvascular maturation and alveolarization, as well as antioxidant therapies in the setting of hyperoxia-induced neonatal lung injury are reviewed in this article.

Why should neuroscientists worry about iron? The emerging role of ferroptosis in the pathophysiology of neuroprogressive diseases

Ferroptosis is a unique form of programmed death, characterised by cytosolic accumulation of iron, lipid hydroperoxides and their metabolites, and effected by the fatal peroxidation of polyunsaturated fatty acids in the plasma membrane. It is a major driver of cell death in neurodegenerative neurological diseases. Moreover, cascades underpinning ferroptosis could be active drivers of neuropathology in major psychiatric disorders. Oxidative and nitrosative stress can adversely affect mechanisms and proteins governing cellular iron homeostasis, such as the iron regulatory protein/iron response element system, and can ultimately be a source of abnormally high levels of iron and a source of lethal levels of lipid membrane peroxidation. Furthermore, neuroinflammation leads to the upregulation of divalent metal transporter1 on the surface of astrocytes, microglia and neurones, making them highly sensitive to iron overload in the presence of high levels of non-transferrin-bound iron, thereby affording such levels a dominant role in respect of the induction of iron-mediated neuropathology. Mechanisms governing systemic and cellular iron homeostasis, and the related roles of ferritin and mitochondria are detailed, as are mechanisms explaining the negative regulation of ferroptosis by glutathione, glutathione peroxidase 4, the cysteine/glutamate antiporter system, heat shock protein 27 and nuclear factor erythroid 2-related factor 2. The potential role of DJ-1 inactivation in the precipitation of ferroptosis and the assessment of lipid peroxidation are described. Finally, a rational approach to therapy is considered, with a discussion on the roles of coenzyme Q₁₀, iron chelation therapy, in the form of deferiprone, deferoxamine (desferrioxamine) and deferasirox, and N-acetylcysteine.

Inhibition of lipoxygenase by sesamol corroborates its potential anti-inflammatory activity

Reactive oxygen species, the byproducts of oxygenases reaction, when in excess, promote degenerative diseases like cardiovascular, cancer and arthritis. Sesame lignans- sesamin, sesamolin and the phenolic degradation product of sesamolin, sesamol, are empirically known for their health promoting properties like antioxidant, antimutagenic, antiaging and antiinflammatory activities. In the current study, the effect of sesamol on the inflammatory oxygenase - lipoxygenase (LOX) was investigated. Enzyme kinetics and spectroscopic techniques were used to understand the inhibition mechanism. Sesamol was a potent inhibitor of soy LOX-1. It inhibited soy LOX-1 in a dose dependent manner with IC50 value of 51.84μM and Ki of 4.9μM. Binding studies using circular dichroism and corroborated by surface plasmon resonance, revealed that sesamol does not bind or change the conformation of LOX. Further, sesamol prevented the conversion of inactive LOX (Fe2+) to active LOX (Fe3+) by arresting the oxidation state of iron and prolonging the lag phase by virtue of its ability to scavenge hydroperoxides. Understanding the mechanism of action of such molecules will help in their application and promotion as nutraceuticals.

Antibody-Directed Glucocorticoid Targeting to CD163 in M2-type Macrophages Attenuates Fructose-Induced Liver Inflammatory Changes

Increased consumption of high-caloric carbohydrates contributes substantially to endemic non-alcoholic fatty liver disease in humans, covering a histological spectrum from fatty liver to steatohepatitis. Hypercaloric intake and lipogenetic effects of fructose and endotoxin-driven activation of liver macrophages are suggested to be essential to disease progression. In the present study, we show that a low dose of an anti-CD163-IgG-dexamethasone conjugate targeting the hemoglobin scavenger receptor CD163 in Kupffer cells and other M2-type macrophages has a profound effect on liver inflammatory changes in rats on a high-fructose diet. The diet induced severe non-alcoholic steatohepatitis (NASH)-like changes within a few weeks but the antibody-drug conjugate strongly reduced inflammation, hepatocyte ballooning, fibrosis, and glycogen deposition. Non-conjugated dexamethasone or dexamethasone conjugated to a control IgG did not have this effect but instead exacerbated liver lipid accumulation. The low-dose anti-CD163-IgG-dexamethasone conjugate displayed no apparent systemic side effects. In conclusion, macrophage targeting by antibody-directed anti-inflammatory low-dose glucocorticoid therapy seems to be a promising approach for safe treatment of fructose-induced liver inflammation.

15-Lipoxygenase metabolites of α-linolenic acid, [13-(S)-HPOTrE and 13-(S)-HOTrE], mediate anti-inflammatory effects by inactivating NLRP3 inflammasome

The ratio of ω-6 to ω-3 polyunsaturated fatty acids (PUFAs) appears to be critical in the regulation of various pathophysiological processes and to maintain cellular homeostasis. While a high proportion of dietary intake of ω-6 PUFAs is associated with various inflammatory disorders, higher intake of ω-3 PUFAs is known to offer protection. It is now well established that beneficial effects of ω-3 PUFAs are mediated in part by their oxygenated metabolites mainly via the lipoxygenase (LOX) and cyclooxygenase (COX) pathways. However, the down-stream signaling pathways that are involved in these anti-inflammatory effects of ω-3 PUFAs have not been elucidated. The present study evaluates the effects of 15-LOX metabolites of α-linolenic acid (ALA, ω-3 PUFA) on lipopolysaccharide (LPS) induced inflammation in RAW 264.7 cells and peritoneal macrophages. Further, the effect of these metabolites on the survival of BALB/c mice in LPS mediated septic shock and also polymicrobial sepsis in Cecal Ligation and Puncture (CLP) mouse model was studied. These studies reveal the anti-inflammatory effects of 13-(S)-hydroperoxyoctadecatrienoic acid [13-(S)-HPOTrE] and 13-(S)-hydroxyoctadecatrienoic acid [13-(S)-HOTrE] by inactivating NLRP3 inflammasome complex through the PPAR-γ pathway. Additionally, both metabolites also deactivated autophagy and induced apoptosis. In mediating all these effects 13-(S)-HPOTrE was more potent than 13-(S)-HOTrE.

COX-2 inhibitor NS-398 suppresses doxorubicin-induced p53 accumulation through inhibition of ROS-mediated Jnk activation

Cyclooxygenase-2 (COX-2) is one of the isoforms of cyclooxygenase, a rate-limiting enzyme in the arachidonic acid cascade. COX-2 protein expression is highly induced by numerous factors and it has been reportedly overexpressed in various human malignancies. Although anti-tumorigenic effects of COX-2 inhibitors have been shown, several lines of evidence suggest that COX-2 inhibitors antagonize the cytotoxicity of chemotherapeutic agents. In this study, we investigated the effect of NS-398, a COX-2 inhibitor, on modulation of doxorubicin (DOX)-induced p53 accumulation. Non-selective and selective COX-2 inhibitors attenuated DOX-induced accumulation of wild type (WT) but not mutant p53. Nutlin-3α or MG132 abolished the suppressive effect of a COX-2 inhibitor on DOX-induced p53 increase. Moreover, the DOX-induced increase in p53 protein levels was reduced in COX-2 knockout (KO) mouse embryonic fibroblasts (MEFs) compared to those in WT or COX-1 KO MEFs. DOX-induced accumulation of p53 was attenuated by a specific inhibitor or knockdown of Jun-N-terminal kinase (Jnk). In addition, DOX-induced Jnk activation was decreased in COX-2 KO MEFs or by COX-2 inhibition, suggesting that Jnk stabilizes p53 by a mechanism that involves COX-2. Pre-treatment with a reactive oxygen species (ROS) scavenger, N-acetylcysteine, attenuated DOX-induced Jnk activation and subsequent p53 accumulation. Furthermore, the absence or inhibition of COX-2 resulted in suppression of DOX-induced increase in ROS levels. These results suggest that COX-2 activates Jnk through modulation of ROS levels, leading to accumulation of p53. Our study identifies a putative novel cross-talk between COX-2 and p53. © 2016 Wiley Periodicals, Inc.

Caruifolin D from artemisia absinthium L. inhibits neuroinflammation via reactive oxygen species-dependent c-jun N-terminal kinase and protein kinase c/NF-κB signaling pathways

This work aims to evaluate the anti-neuroinflammatory effects of natural sesquiterpene dimer caruifolin D from Artemisia absinthium L., which is an edible vegetable or traditional medicinal food in East Asia due to its sedation, anti-asthma and antipruritic effects. In this study, we reported that caruifolin D significantly inhibited the productions of various neuroinflammatory mediators from microglia in response to bacterial lipopolysaccharide stimulation. Moreover, anti-inflammatory mechanism study showed that caruifolin D markedly suppressed the production of intracellular reactive oxygen species, which was an important player involved in neuroinflammation, leading to inhibitory effects on the activations of protein kinase C (PKC) and c-Jun N-terminal kinase (JNK), which were two major neuroinflammatory signaling pathways in the brains. Furthermore, caruifolin D protected neurons against microglia-mediated neuronal inflammatory damages by up-regulating neuronal viability and maintaining healthy neuronal morphology. Taken together, these results expanded our knowledge about the anti-neuroinflammatory and neuroprotective mechanism of Artemisia absinthium L., and also suggested that caruifolin D was a major anti-inflammatory component from Artemisia absinthium L., which might be developed as a drug candidate for neuroinflammation-related diseases.

5-Lipoxygenase inhibitors attenuate TNF-α-induced inflammation in human synovial fibroblasts

The lipoxygenase isoform of 5-lipoxygenase (5-LOX) is reported to be overexpressed in human rheumatoid arthritis synovial tissue and involved in the progress of inflammatory arthritis. However, the detailed mechanism of how 5-lipoxygenase regulates the inflammatory response in arthritis synovial tissue is still unclear. The aim of this study was to investigate the involvement of lipoxygenase pathways in TNF-α-induced production of cytokines and chemokines. Human synovial fibroblasts from rheumatoid patients were used in this study. 5-LOX inhibitors and shRNA were used to examine the involvement of 5-LOX in TNF-α-induced cytokines and chemokines expression. The signaling pathways were examined by Western Blotting or immunofluorescence staining. The effect of 5-LOX inhibitor on TNF-α-induced chemokine expression and paw edema was also explored invivo in C57BL/6 mice. Treatment with 5-LOX inhibitors significantly decreased TNF-α-induced pro-inflammatory mediators including interleukin-6 (IL-6) and monocyte chemo-attractant protein-1 (MCP-1) in human synovial fibroblasts. Knockdown of 5-LOX using shRNA exerted similar inhibitory effects. The abrogation of NF-κB activation was involved in the antagonizing effects of these inhibitors. Furthermore, 5-LOX inhibitor decreased TNF-α-induced up-regulation of serum MCP-1 level and paw edema in mouse model. Our results provide the evidence that the administration of 5-LOX inhibitors is able to ameliorate TNF-α-induced cytokine/chemokine release and paw edema, indicating that 5-LOX inhibitors may be developed for therapeutic treatment of inflammatory arthritis.

Oxidative Stress and Therapeutic Development in Lung Diseases

Oxidative stress has many implications in the pathogenesis of lung diseases. In this review, we provide an overview of Reactive Oxygen Species (ROS) and nitrogen (RNS) species and antioxidants, how they relate to normal physiological function and the pathophysiology of different lung diseases, and therapeutic strategies. The production of ROS/RNS from endogenous and exogenous sources is first discussed, followed by antioxidant systems that restore oxidative balance and cellular homeostasis. The contribution of oxidant/antioxidant imbalance in lung disease pathogenesis is also discussed. An overview of therapeutic strategies is provided, such as augmenting NO bioactivity, blocking the production of ROS/RNS and replacement of deficient antioxidants. The limitations of current strategies and failures of clinical trials are then addressed, followed by discussion of novel experimental approaches for the development of improved antioxidant therapies.

Nordihydroguaiaretic acid attenuates the oxidative stress-induced decrease of CD33 expression in human monocytes

Nordihydroguaiaretic acid (NDGA) is a natural lignan with recognized antioxidant and beneficial properties that is isolated from Larrea tridentata. In this study, we evaluated the effect of NDGA on the downregulation of oxidant stress-induced CD33 in human monocytes (MNs). Oxidative stress was induced by iodoacetate (IAA) or hydrogen peroxide (H₂O₂) and was evaluated using reactive oxygen species (ROS) production, and cell viability. NDGA attenuates toxicity, ROS production and the oxidative stress-induced decrease of CD33 expression secondary to IAA or H₂O₂ in human MNs. It was also shown that NDGA (20 μM) attenuates cell death in the THP-1 cell line that is caused by treatment with either IAA or H₂O₂. These results suggest that NDGA has a protective effect on CD33 expression, which is associated with its antioxidant activity in human MNs.

Ligation of CD40 receptor in human B lymphocytes triggers the 5-lipoxygenase pathway to produce reactive oxygen species and activate p38 MAPK

Previously, we reported that CD40-induced production of reactive oxygen species (ROS) by NADPH oxidase requires the TNF receptor-associated factor (TRAF) 3, as well as the activities of phosphatidylinositol 3-kinase (PI3K) and Rac1. Here we investigated the possible mechanisms of the production of ROS after CD40 ligation in B cells. We describe an alternative ROS production pathway that is triggered by CD40 ligation, involves 5-lipoxygenase (5-LO), and results in activation of p38 MAPK. Our studies in Raji human B lymphomas revealed that CD40-induced ROS production by 5-LO also requires the activities of PI3K and Rac1. In contrast to the NADPH oxidase pathway, however, TRAF molecules are not required for the CD40-induced ROS production by 5-LO. The association of CD40 with 5-LO is dependent on CD40 ligation in Raji B cells, and co-immunoprecipitation experiments using epitope- tagged proteins transiently expressed in human embryonic kidney 293T cells revealed the role of the regulatory subunit of PI3K, p85, in this association. Collectively, these data suggest a separate pathway for the CD40-induced ROS production in B cells and demonstrate that this pathway requires 5-LO via direct association of p85 with both CD40 and 5-LO.

Anti-inflammatory effects of apocynin, an inhibitor of NADPH oxidase, in airway inflammation

Oxidative stress is implicated in the pathogenesis of allergic asthma and remains an attractive target for the prevention of the disease. Herein, we investigated the anti-inflammatory effects of apocynin, a NADPH oxidase (NOX) inhibitor, in both in vitro and in vivo allergen-induced experimental asthma mediated by Th2 hyperresponsiveness. Apocynin showed potential antioxidant activities and inhibitory effects on the activation of redox-sensitive transcription factors, such as NF-κB and AP-1, induced by pro-inflammatory stimuli, such as TNF-α, lipopolysaccharide and Poly I:C, and that inhibited the production of pro-inflammatory cytokines, such as TNF-α, IL-1β and IL-6. In in vivo experimental asthma model, moreover, apocynin significantly attenuated ovalbumin-induced airway hyperresponsiveness and inflammation, as shown by the attenuation of total inflammatory cell and soluble product influx into bronchoalveolar lavage fluid, such as macrophages, eosinophils, IL-4, IL-5, IL-12, IL-13 and TNF-α. Apocynin also significantly reduced lung inflammation in the tissues. Altogether, these results suggest that apocynin may be useful in the treatment of inflammatory diseases induced by oxidative stress through NOX activity.

Association between genetic variations of the transforming growth factor ß receptor type III and asthma in a Korean population

Transforming growth factor-beta (TGF-ß) and its receptors have been suggested to play key roles in the pathogenesis of asthma. The aim of this study was to evaluate the effects of genetic variations in the TGF-ß receptor type III (TGFBR3) on asthma and on its related phenotypes in the general population. A cohort of 2,118 subjects aged from 10 to 18 years responded to a questionnaire concerning asthma symptoms and risk factors. Methacholine airway hyperresponsiveness (AHR), skin test responses to common aeroallergens, and serum total IgE levels were evaluated in the cohort. A total of 19 SNPs for TGFBR3 were found using direct re-sequencing in 24 healthy adults. Of these, informative SNPs [+44T>C (S15F) and +2753G>A at 3'UTR] were selected and scored using the high throughput single base extension method. Atopy was identified in subjects with 44T>C allele [P=0.04, OR (95% CI)=0.79 (0.62-0.99)] and in subjects with Ht1 (CG) more frequently than in subjects with other haplotypes [P=0.04, OR (95% CI)=1.27 (1.01-1.59)]. The A allele in 2753G>A was more common in subjects with non-atopic asthma [OR (95% CI)=1.76 (1.01-3.05)]. A significant association was found between non-atopic asthma and 44T_2753A [OR (95% CI) =2.16 (1.22-3.82)]. Genetic variations in TGFBR3 appear to be associated with a genetic predisposition to development of asthma and to phenotypes of asthma. Also, the minor allele 2753G and the haplotype TA in the TGFBR3 gene were associated with a pathogenesis of non-atopic asthma.