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Thyroid dyshormonogenesis (THD) is a heterogeneous group of genetic diseases caused by the total or partial defect in the synthesis or secretion of thyroid hormones. Genetic variants in DUOX2 can cause partial to total iodination organification defects and clinical heterogeneity, from transient to permanent congenital hypothyroidism. The aim of this study was to undertake a molecular characterization and genotype-phenotype correlation in patients with THD and candidate variants in DUOX2. A total of 31 (19.38%) patients from the Catalan Neonatal Screening Program presented with variants in DUOX2 that could explain their phenotype. Fifteen (48.39%) patients were compound heterozygous, 10 (32.26%) heterozygous, and 4 (12.90%) homozygous. In addition, 8 (26.67%) of these patients presented variants in other genes. A total of 35 variants were described, 10 (28.57%) of these variants have not been previously reported in literature. The most frequent variant in our cohort was c.2895_2898del/p.(Phe966SerfsTer29), classified as pathogenic according to reported functional studies. The final diagnosis of this cohort was permanent THD in 21 patients and transient THD in 10, according to reevaluation and/or need for treatment with levothyroxine. A clear genotype-phenotype correlation could not be identified; therefore, functional studies are necessary to confirm the pathogenicity of the variants.

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Hydrogen peroxide, produced by Dual Oxidase (Duox), is essential for thyroid hormone synthesis. Duox activation involves Ca2+ binding to its EF-hand Domain (EFD), which contains two EF-hands (EFs). In this study, we characterized a truncated EFD using spectrometry, calorimetry, electrophoretic mobility, and gel filtration to obtain its Ca2+ binding thermodynamic and kinetics, as well as to assess the associated conformational changes. Our results revealed that its 2nd EF-hand (EF2) exhibits a strong exothermic Ca2+ binding (Ka = 107 M-1) while EF1 shows a weaker binding (Ka = 105 M-1), resulting in the burial of its negatively charged residues. The Ca2+ binding to EFD results in a stable structure with a melting temperature shifting from 67 to 99 °C and induces a structural transition from a dimeric to monomeric form. EF2 appears to play a role in dimer formation in its apo form, while the hydrophobic exposure of Ca2+-bound-EF1 is crucial for dimer formation in its holo form. The result is consistent with structures obtained from Cryo-EM, indicating that a stable structure of EFD with hydrophobic patches upon Ca2+ binding is vital for its Duox's domain-domain interaction for electron transfer.

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BACKGROUND: Oxidative stress is implicated in the pathogenesis of heart failure. Dual oxidase 1 (DUOX1) might be important in heart failure development through its mediating role in oxidative stress. This study was designed to evaluate the potential role of DUOX1 in heart failure. MATERIALS AND METHODS: AC16 cells were treated with 2 µmol/L of doxorubicin (DOX) for 12, 24, and 48 h to construct a heart failure model. DUOX1 overexpression and silencing in AC16 cell were established. DUOX1 expression was detected by Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. Pyroptosis and reactive oxygen species (ROS) production were measured by flow cytometry. RESULTS: Increased DUOX1 expression levels were observed after DOX treatment for 24 h in AC16 cells. DUOX1 silencing inhibited DOX-induced pyroptosis and ROS production. The release of IL-1ß, IL-18, and lactate dehydrogenase (LDH), and expression levels of pyroptosis-related proteins were also decreased. DUOX1 overexpression increased pyroptosis, ROS production, IL-1ß, IL-18, and LDH release, and pyroptosis-related protein expression. N-acetyl-cysteine (NAC) significantly reversed DUOX1-induced pyroptosis, ROS, and related factors. CONCLUSION: These results suggest that DUOX1-derived genotoxicity could promote heart failure development. In the process, oxidative stress and pyroptosis may be involved in the regulation of DUOX1 in heart failure.

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Dual oxidase (Duox) a member of the nicotinamide adenine dinucleotide phosphate oxidase (NOX) family can induce the production of reactive oxygen species (ROS). In vertebrates, the duox gene was indicated to be associated with the mucosal immunity. The roles of the duox gene in invertebrates were mainly studied in insects for the function of maintaining intestinal flora balance. In recent years, some studies have reported that Duox is involved in regulating the production of ROS and plays an important role in defending against the intestinal pathogen infection. However, the molecular mechanism has not been fully illuminated. In this study, a duox 2 involved in the production of H2O2 was identified for the first time in P. clarkii. Mature Pc-Duox 2 is a 7-transmembrane protein molecule that includes PHD, FAD, and NAD domains. Pc-duox 2 was mainly expressed in hemocytes and intestinal tissue. Its expression levels were obviously upregulated after intramuscular or oral infection with V. harveyi. In the RNAi assay, the upregulated trends of H2O2 and total ROS levels in crayfish intestine were significantly suppressed when Pc-duox 2 was knocked down. Compared with the slightly affected SOD activity, the upregulated CAT activity was suppressed more obviously in the crayfish intestine. Furthermore, Pc-duox 2 had an important effect on the maintenance of the structural stability of crayfish the intestine. Further research revealed that the knockdown of Pc-duox 2 could cause an obvious suppression in the upregulated levels of Toll signalling pathway-related genes, including Pc-toll 1, Pc-toll 3, Pc-dorsal, Pc-ALF 5, Pc-crustin 1, and Pc-lysozyme. Ultimately, these changes triggered the accelerated death of crayfish. Overall, we speculated that Pc-duox 2 played an important role in antibacterial innate immunity in the crayfish intestine by regulating the total ROS level.

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Laryngeal squamous cell carcinoma (LSCC) is the second most common head and neck cancer. To identify the link between ferroptosis and LSCC, we targeted the dual oxidase 1 (DUOX1) gene. This study aimed to reveal the intrinsic mechanism by which the DUOX1-zinc-finger CCCH domain-containing protein 13 (ZC3H13) ferroptosis axis affected the LSCC process. GEPIA was used to investigate the expression of DUOX1 in LSCC, and the expression levels of DUOX1 and ZC3H13 were manipulated by overexpression and RNA interference. MTT assay was used to detect cell proliferation. Chromatin immunoprecipitation (CHIP) detected the binding of DUOX1 and ZC3H13, and ROS assessment and intracellular Fe2+ content determination were performed to examine the ferroptosis. MeRIP was used to analyze the m6A methylation of DUOX1. Ferroptosis-related proteins were detected by qRT-PCR. DUOX1 was found to be poorly expressed in LSCC cells, low DUOX1 level promoted LSCC cell proliferation, and low ZC3H13 level decreased LSCC cell proliferation. Besides, there was an interaction between DUOX1 and ZC3H13. DUOX1 could inhibit the expression levels of ferroptosis-related genes GPX4 and F1H1 in LSCC cells DUOX1 inhibited the expression levels of ROS and ferroptosis-related genes GPX4 and F1H1 and increased intracellular iron content in LSCC cells, but ZC3H13 reversed this phenomenon by inhibiting DUOX1 gene through m6A methylation modification. ZC3H13 reduced DUOX1-mediated ferroptosis in LSCC cells through m6A-dependent modification. The regulatory pathway of DUOX1 and ferroptosis are potential targets for designing diagnostic and combination therapeutic strategies for LSCC patients.

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Pro-inflammatory cytokines upregulate the expression of the H2O2-producing NADPH oxidase dual oxidase 2 (DUOX2)2 which, when elevated, adversely affects survival from pancreatic ductal adenocarcinoma (PDAC). Because the cGAS-STING pathway is known to initiate pro-inflammatory cytokine expression following uptake of exogenous DNA, we examined whether activation of cGAS-STING could play a role in the generation of reactive oxygen species by PDAC cells. Here, we found that a variety of exogenous DNA species markedly increased the production of cGAMP, the phosphorylation of TBK1 and IRF3, and the translocation of phosphorylated IRF3 into the nucleus, leading to a significant, IRF3-dependent enhancement of DUOX2 expression, and a significant flux of H2O2 in PDAC cells. However, unlike the canonical cGAS-STING pathway, DNA-related DUOX2 upregulation was not mediated by NF-κB. Although exogenous IFN-ß significantly increased Stat1/2-associated DUOX2 expression, intracellular IFN-ß signaling that followed cGAMP or DNA exposure did not itself increase DUOX2 levels. Finally, DUOX2 upregulation subsequent to cGAS-STING activation was accompanied by the enhanced, normoxic expression of HIF-1α and VEGF-A as well as DNA double strand cleavage, suggesting that cGAS-STING signaling may support the development of an oxidative, pro-angiogenic microenvironment that could contribute to the inflammation-related genetic instability of pancreatic cancer.

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In the arthropod gut, commensal microbiota maintain the immune deficiency (Imd)/Relish pathway for expression of antimicrobial peptides, whereas pathogenic bacteria induce dual oxidase 2 (Duox2) for production of extracellular microbicidal reactive oxygen species (ROS). The Imd/Relish pathway and the Duox2/ROS system are regarded as independent systems. Here, we report that these two systems are bridged by the tumor necrosis factor (TNF) ortholog PcEiger in the red swamp crayfish Procambarus clarkii. PcEiger expression is induced by commensal bacteria or the Imd/Relish pathway. PcEiger knockdown alters bacterial abundance and community composition due to variations in the oxidative status of the intestine. PcEiger induces Duox2 expression and ROS production by regulating the activity of the transcription factor Atf2. Moreover, PcEiger mediates regulation of the Duox2/ROS system by commensal bacteria and the Imd/Relish pathway. Our findings suggest that the Imd/Relish pathway regulates the Duox2/ROS system via PcEiger in P. clarkii, and they provide insights into the crosstalk between these two important mechanisms for arthropod intestinal immunity.

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Keratinocytes of the mammalian skin provide not only mechanical protection for the tissues, but also transmit mechanical, chemical, and thermal stimuli from the external environment to the sensory nerve terminals. Sensory nerve fibers penetrate the epidermal basement membrane and function in the tight intercellular space among keratinocytes. Here we show that epidermal keratinocytes produce hydrogen peroxide upon the activation of the NADPH oxidase dual oxidase 1 (DUOX1). This enzyme can be activated by increasing cytosolic calcium levels. Using DUOX1 knockout animals as a model system we found an increased sensitivity towards certain noxious stimuli in DUOX1-deficient animals, which is not due to structural changes in the skin as evidenced by detailed immunohistochemical and electron-microscopic analysis of epidermal tissue. We show that DUOX1 is expressed in keratinocytes but not in the neural sensory pathway. The release of hydrogen peroxide by activated DUOX1 alters both the activity of neuronal TRPA1 and redox-sensitive potassium channels expressed in dorsal root ganglia primary sensory neurons. We describe hydrogen peroxide, produced by DUOX1 as a paracrine mediator of nociceptive signal transmission. Our results indicate that a novel, hitherto unknown redox mechanism modulates noxious sensory signals.

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Several excellent guidelines and expert opinions on congenital hypothyroidism (CH) are currently available. Nonetheless, these guidelines do not address several issues related to CH in detail. In this review, the authors chose the following seven clinical issues that they felt were especially deserving of closer scrutiny in the hope that drawing attention to them through discussion would help pediatric endocrinologists and promote further interest in the treatment of CH. 1. How high should the levothyroxine (L-T4) dose be for initial treatment of severe and permanent CH? 2. What is the optimal method for monitoring treatment of severe CH? 3. At what level does maternal iodine intake during pregnancy affect fetal and neonatal thyroid function? 4. Does serum thyroglobulin differ between patients with a dual oxidase 2 (DUOX2) variants and those with excess iodine? 5. Who qualifies for a genetic diagnosis? 6. What is the best index for distinguishing transient and permanent CH? 7. Is there any cancer risk associated with CH? The authors discussed these topics and jointly edited the manuscript to improve the understanding of CH and related issues.

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Objective: Dual oxidases (DUOX1, DUOX2) belong to the NADPH oxidase (NOX) family, which produce H2O2 necessary for thyroid hormone biosynthesis. This study aims to evaluate gene expression for DUOX1, DUOX2 in PCOS patients and its relation with thyroid hormone and magnesium levels. Materials and methods: Totally 88 cases were studied including 24 people with PCOS and hypothyroidism, 44 people with PCOS and normal thyroid function, and 20 hypothyroid patients without PCOS. In comparison 40 healthy controls in the age group of 16-35 years matched for age group and BMI were evaluated. Using Vegaro syringe 5 cc of blood was sampled from all 128 people and after RNA extraction and cDNA synthesis using Real-Time PCR technique, the expression level of DUOX1 and DUOX2 genes was investigated. Results: The results of hormonal tests showed that there is a significant difference between the level of T4, T3, and TSH hormones in hypothyroid patients with or without PCOS in comparison to the control group. Regarding the level of Mg, the results showed that there is a significant difference between the levels of Mg in PCOS group with or without hypothyroidism in comparison to the control group. Gene expression results showed that the relative changes of DUOX1 gene expression in different groups compared to the control group were significantly reduced P<0.05. In the polycystic group with hypothyroidism, the gene expression level showed a decrease compared to the normo-thyroid polycystic group and the hypothyroid non-PCO group, which was statistically significant P<0.05. Conclusion: According to the results of the present study and the previous studies that have been published in the field of Duox1, it can be assumed that the reduction of Duox1 expression can interfere with the oxidative stress system. Further studies with other molecular techniques may help to understand the exact action mechanism of these genes.

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BACKGROUND: Many genetic and metabolic diseases affect the liver, but diagnosis can be difficult because these diseases may have complex clinical manifestations and diverse clinical patterns. There is also incomplete clinical knowledge of these many different diseases and limitations of current testing methods. CASE SUMMARY: We report a 53-year-old female from a rural area in China who was hospitalized for lower limb edema, abdominal distension, cirrhosis, and hypothyroidism. We excluded the common causes of liver disease (drinking alcohol, using traditional Chinese medicines, hepatitis virus infection, autoimmunity, and hepatolenticular degeneration). When she was 23-years-old, she developed night-blindness that worsened to complete blindness, with no obvious cause. Her parents were first cousins, and both were alive. Analysis of the patient's family history indicated that all 5 siblings had night blindness and impaired vision; one sister was completely blind; and another sister had night-blindness complicated with cirrhosis and subclinical hypothyroidism. Entire exome sequencing showed that the patient, parents, and siblings all had mutations in the cytochrome P450 4V2 gene (CYP4V2). The CYP4V2 mutations of the parents and two sisters were heterozygous, and the others were homozygous. Two siblings also had heterozygous dual oxidase activator 2 (DUOXA2) mutations. CONCLUSION: Mutations in the CYP4V2 gene may affect lipid metabolism and lead to chronic liver injury, fibrosis, and cirrhosis.

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Mechanisms of cancer cell recognition and elimination by the innate immune system remains unclear. The immune signaling pathways are activated in the fat body to suppress the tumor growth in mxcmbn1 hematopoietic tumor mutants in Drosophila by inducing antimicrobial peptides (AMP). Here, we investigated the regulatory mechanism underlying the activation in the mutant. Firstly, we found that reactive oxygen species (ROS) accumulated in the hemocytes due to induction of dual oxidase and one of its activators. This was required for the AMP induction and the tumor growth suppression. Next, more hemocytes transplanted from normal larvae were associated with the mutant tumor than normal lymph glands (LGs). Matrix metalloproteinase 1 and 2 (MMP2) were highly expressed in the tumors. The basement membrane components in the tumors were reduced and ultimately lost inside. Depletion of the MMP2 rather than MMP1 resulted in a significantly reduced AMP expression in the mutant larvae. The hemocytes may recognize the disassembly of basement membrane in the tumors and activate the ROS production. Our findings highlight the mechanism via which macrophage-like hemocytes recognize tumor cells and subsequently convey the information to induce AMPs in the fat body. They contribute to uncover the role of innate immune system against cancer.

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BACKGROUND: Metazoan guts are in permanent contact with microbial communities. However, the host mechanisms that have developed to manage the dynamic changes of these microorganisms and maintain homeostasis remain largely unknown. RESULTS: Serotonin (5-hydroxytryptamine [5-HT]) was found to modulate gut microbiome homeostasis via regulation of a dual oxidase (Duox) gene expression in both Bactrocera dorsalis and Aedes aegypti. The knockdown of the peripheral 5-HT biosynthetic gene phenylalanine hydroxylase (TPH) increased the expression of Duox and the activity of reactive oxygen species, leading to a decrease in the gut microbiome load. Moreover, the TPH knockdown reduced the relative abundance of the bacterial genera Serratia and Providencia, including the opportunistic pathogens, S. marcescens and P. alcalifaciens in B. dorsalis. Treatment with 5-hydroxytryptophan, a precursor of 5-HT synthesis, fully rescued the TPH knockdown-induced phenotype. CONCLUSIONS: The findings reveal the important contribution of 5-HT in regulating gut homeostasis, providing new insights into gut-microbe interactions in metazoans.

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Several mosquitoes transmit human pathogens by blood feeding, with the gut being the main entrance for the pathogens. Thus, the gut epithelium defends the pathogens by eliciting potent immune responses. However, it was unclear how the mosquito gut discriminates pathogens among various microflora in the lumen. This study proposed a hypothesis that a damage signal might be specifically induced by pathogens in the gut. The Asian tiger mosquito, Aedes albopictus, encodes dorsal switch protein 1 (Aa-DSP1) as a putative damage-associated molecular pattern (DAMP). Aa-DSP1 was localized in the nucleus of the midgut epithelium in naïve larvae. Upon infection by a pathogenic bacterium, Serratia marcescens, Aa-DSP1 was released to hemocoel and activated phospholipase A2 (PLA2). The activated PLA2 increased the level of prostaglandin E2 (PGE2) in the gut and subsequently increased Ca2+ signal to produce reactive oxygen species (ROS) via dual oxidase (Duox). Inhibition of Aa-DSP1 via RNA interference or specific inhibitor treatment failed to increase PGE2/Ca2+ signal upon the bacterial infection. Thus, the inhibitors specifically targeting eicosanoid biosynthesis significantly prevented the upregulation of ROS production in the gut and enhanced mosquito mortality after the bacterial infection. However, such inhibitory effects were rescued by adding PGE2. These suggest that Aa-DSP1 plays an important role in immune response of the mosquito gut as a DAMP during pathogen infection by triggering a signaling pathway, DSP1/PLA2/Ca2+/Duox.

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Genetic variants affecting the function of dual oxidase 2 (DUOX2), the catalytic subunit of membrane-bound enzymes that produce hydrogen peroxide, are associated with very early-onset inflammatory bowel disease (VEO-IBD). We report the case of a 1-year-old boy diagnosed with VEO-IBD after presenting with bloody diarrhea. He had pancolitis and an extensive small intestinal ulcerative lesion at age 4 years. Infliximab treatment was successful but was discontinued due to delayed reaction. At age 7 years, treatment with ustekinumab was started, and remission has been maintained for more than 2 years. Whole-exome sequencing identified compound heterozygous missense DUOX2 variants of unknown significance (p.[R1212H];[F1490Y]). Protein expression in the whole-cell lysate and plasma membrane was lower in F1490Y-DUOX2 than in wild-type (WT)-DUOX2. Hydrogen peroxide generation upon ionomycin stimulation was lower in cells expressing R1212H-DUOX2 and F1490Y-DUOX2 than in those expressing WT-DUOX2. The novel, inherited, biallelic DUOX2 mutations may be molecular risk factors of VEO-IBD.

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Background & Aims: MicroRNAs (miRNAs) act as a regulatory mechanism on a post-transcriptional level by repressing gene transcription/translation and play a central role in the cellular stress response. Osmotic changes occur in a variety of diseases including liver cirrhosis and hepatic encephalopathy. Changes in cell hydration and alterations of the cellular volume are major regulators of cell function and gene expression. In this study, the modulation of hepatic gene expression in response to hypoosmolarity was studied. Methods: mRNA analyses of normo- and hypoosmotic perfused rat livers by gene expression arrays were used to identify miRNA and their potential target genes associated with cell swelling preceding cell proliferation. Selected miR-141-3p was also investigated in isolated hepatocytes treated with miRNA mimic, cell stretching, and after partial hepatectomy. Inhibitor perfusion studies were performed to unravel signalling pathways responsible for miRNA upregulation. Results: Using genome-wide transcriptomic analysis, it was shown that hypoosmotic exposure led to differential gene expression in perfused rat liver. Moreover, miR-141-3p was upregulated by hypoosmolarity in perfused rat liver and in primary hepatocytes. In concert with this, miR-141-3p upregulation was prevented after Src-, Erk-, and p38-MAPK inhibition. Furthermore, luciferase reporter assays demonstrated that miR-141-3p targets cyclin dependent kinase 8 (Cdk8) mRNA. Partial hepatectomy transiently upregulated miR-141-3p levels just after the initiation of hepatocyte proliferation, whereas Cdk8 mRNA was downregulated. The mechanical stretching of rat hepatocytes resulted in miR-141-3p upregulation, whereas Cdk8 mRNA tended to decrease. Notably, the overexpression of miR-141-3p inhibited the proliferation of Huh7 cells. Conclusions: Src-mediated upregulation of miR-141-3p was found in hepatocytes in response to hypoosmotic swelling and mechanical stretching. Because of its antiproliferative function, miR-141-3p may counter-regulate the proliferative effects triggered by these stimuli. Lay summary: In this study, we identified microRNA 141-3p as an osmosensitive miRNA, which inhibits proliferation during liver cell swelling. Upregulation of microRNA 141-3p, controlled by Src-, Erk-, and p38-MAPK signalling, results in decreased mRNA levels of various genes involved in metabolic processes, macromolecular biosynthesis, and cell cycle progression.

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Neurons respond to changes in the levels of activity they experience in a variety of ways, including structural changes at pre- and postsynaptic terminals. An essential plasticity signal required for such activity-regulated structural adjustments are reactive oxygen species (ROS). To identify sources of activity-regulated ROS required for structural plasticity in vivo we used the Drosophila larval neuromuscular junction as a highly tractable experimental model system. For adjustments of presynaptic motor terminals, we found a requirement for both NADPH oxidases, Nox and dual oxidase (Duox), that are encoded in the Drosophila genome. This contrasts with the postsynaptic dendrites from which Nox is excluded. NADPH oxidases generate ROS to the extracellular space. Here, we show that two aquaporins, Bib and Drip, are necessary ROS conduits in the presynaptic motoneuron for activity regulated, NADPH oxidase dependent changes in presynaptic motoneuron terminal growth. Our data further suggest that different aspects of neuronal activity-regulated structural changes might be regulated by different ROS sources: changes in bouton number require both NADPH oxidases, while activity-regulated changes in the number of active zones might be modulated by other sources of ROS. Overall, our results show NADPH oxidases as important enzymes for mediating activity-regulated plasticity adjustments in neurons.

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Introduction:Neutrophil transmigration is multifactorial and primarily driven by selectins and ß2-integrins (CD11b/CD18), whose expression are dependent on the underlying stimulus. Ventilator-induced lung injury (VILI) results in a predominantly CD18-independent mechanism of neutrophil recruitment, while direct endotoxin-induced lung injury results from a CD18-dependent mechanism. We previously observed that lack of NADPH oxidases DUOX1 and DUOX2 resulted in reduced neutrophil influx in a VILI model of lung injury but had no influence on neutrophil influx after LPS exposure. Based on these observations, we hypothesized that DUOX1/DUOX2 are an important component of CD18-independent mechanisms of neutrophil recruitment in the lung. Methods:We exposed Duoxa -/- (KO) mice and Duoxa +/+ (WT) mice to either an intratracheal exposure of lipopolysaccharide (LPS/endotoxin)-or high tidal volume ventilation and compared expression of neutrophil markers between groups. WT mice (129S6/SvEvTac) were obtained from Taconic Biosciences (One Discovery Drive Suite 304; Rensselaer, NY 1244) and were allowed to acclimatize for one week prior to study enrollment. KO mice were generated as previously described [Grasberger 2012] and bred in-house on a 129S6 background. We provided positive-pressure ventilation at a tidal volume of 10 ml/kg with 2 cmH20 positive end-expiratory pressure (PEEP). Mice were assigned to groups consisting of KO (n = 5) and WT (n = 5) in each group and divided into non-ventilated, positive-pressure ventilation, or LPS IT exposure groups. Positive-pressure ventilation was instituted for 4-h using a FlexiVent (Flexiware 8.1, Scireq, Montreal, QC, Canada). Lipopolysaccharide (Salmonella enterica serotype tryphimurium L6143, Millipore Sigma) was administered via an intratracheal (IT) route at a dose of 0.1 mg/kg. Mice were humanely euthanized at 4-h post-injection consistent with the UC Davis IAUCAC-approved protocol. Results:As previously observed, neutrophilic influx into the airways was significantly impaired in the Duoxa -/- (KO) mice after VILI, but not after LPS exposure. LPS-induced lung injury resulted in upregulation of CD11b+ neutrophils and shedding of CD62L and CD162 regardless of DUOX expression, whereas VILI resulted in upregulation of CD49+ neutrophils in the Duoxa +/+ (WT) mice but not the Duoxa -/- (KO) mice. Conclusion:Our data suggest DUOX is required for CD18-independent mechanisms of neutrophil recruitment in the lung induced by acute lung injury, but not for canonical CD18depedent mechanisms after LPS exposure.

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Aedes aegypti mosquitoes transmit arboviruses of important global health impact, and their intestinal microbiota can influence vector competence by stimulating the innate immune system. Midgut epithelial cells also produce toxic reactive oxygen species (ROS) by dual oxidases (DUOXs) that are essential players in insect immunity. Strigomonas culicis is a monoxenous trypanosomatid that naturally inhabits mosquitoes; it hosts an endosymbiotic bacterium that completes essential biosynthetic pathways of the parasite and influences its oxidative metabolism. Our group previously showed that S. culicis hydrogen peroxide (H2O2)-resistant (WTR) strain is more infectious to A. aegypti mosquitoes than the wild-type (WT) strain. Here, we investigated the influence of both strains on the midgut oxidative environment and the effect of infection on mosquito fitness and immunity. WT stimulated the production of superoxide by mitochondrial metabolism of midgut epithelial cells after 4 days post-infection, while WTR exacerbated H2O2 production mediated by increased DUOX activity and impairment of antioxidant system. The infection with both strains also disrupted the fecundity and fertility of the females, with a greater impact on reproductive fitness of WTR-infected mosquitoes. The presence of these parasites induced specific transcriptional modulation of immune-related genes, such as attacin and defensin A during WTR infection (11.8- and 6.4-fold, respectively) and defensin C in WT infection (7.1-fold). Thus, we propose that A. aegypti oxidative response starts in early infection time and does not affect the survival of the H2O2-resistant strain, which has a more efficient antioxidant system. Our data provide new biological aspects of A. aegypti-S. culicis relationship that can be used later in alternative vector control strategies.

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Treatment options are rather limited for gastrointestinal cancer patients whose disease has disseminated into the intra-abdominal cavity. Here, we designed pre-clinical studies to evaluate the potential application of chemopotentiation by Low Dose Fractionated Radiation Therapy (LDFRT) for disseminated gastric cancer and evaluate the role of a likely biomarker, Dual Oxidase 2 (DUOX2). Nude mice were injected orthotopically with human gastric cancer cells expressing endogenous or reduced levels of DUOX2 and randomly assigned to four treatment groups: 1; vehicle alone, 2; modified regimen of docetaxel, cisplatin and 5'-fluorouracil (mDCF) for three consecutive days, 3; Low Dose- Whole Abdomen Radiation Therapy (LD-WART) (5 fractions of 0.15 Gy in three days), 4; mDCF and LD-WART. The combined regimen increased the odds of preventing cancer dissemination (mDCF + LD-WART OR = 4.16; 80% CI = 1.0, 17.29) in the DUOX2 positive tumors, while tumors expressing lower DUOX2 levels were more responsive to mDCF alone with no added benefit from LD-WART. The molecular mechanisms underlying DUOX2 effects in response to the combined regimen include NF-κB upregulation. These data are particularly important since our study indicates that about 33% of human stomach adenocarcinoma do not express DUOX2. DUOX2 thus seems a likely biomarker for potential clinical application of chemopotentiation by LD-WART.