Insight into the role of TXNRD2 in steroidogenesis through a novel homozygous TXNRD2 splice variant.

OBJECTIVE: Adrenal cortisol production occurs through a biosynthetic pathway which depend on NADH and NADPH for energy supply. The mitochondrial respiratory chain and the reactive oxygen species (ROS) detoxification system are therefore important for steroidogenesis. Mitochondrial dysfunction leading to oxidative stress has been implicated in the pathogenesis of several adrenal conditions. Nonetheless, only very few patients with variants in one gene of the ROS detoxification system, Thioredoxin Reductase 2 (TXNRD2), have been described with variable phenotypes. DESIGN: Clinical, genetic, structural, and functional characterization of a novel, biallelic TXNRD2 splice variant. METHODS: On human biomaterial, we performed whole exome sequencing to identify and RNA analysis to characterize the specific TXNRD2 splice variant. Amino acid conservation analysis and protein structure modeling were performed in silico. Using patient's fibroblast-derived human induced pluripotent stem cells, we generated adrenal-like cells (iALC) to study the impact of wild-type (WT) and mutant TXNRD2 on adrenal steroidogenesis and ROS production. RESULTS: The patient had a complex phenotype of primary adrenal insufficiency (PAI), combined with genital, ophthalmological, and neurological features. He carried a homozygous splice variant c.1348-1G > T in TXNRD2 which leads to a shorter protein lacking the C-terminus and thereby affecting homodimerization and flavin adenine dinucleotide binding. Patient-derived iALC showed a loss of cortisol production with overall diminished adrenal steroidogenesis, while ROS production was significantly increased. CONCLUSION: Lack of TXNRD2 activity for mitochondrial ROS detoxification affects adrenal steroidogenesis and predominantly cortisol production.

The rheumatoid arthritis drug auranofin exerts potent anti-lymphoma effect by stimulating TXNRD-mediated ROS generation and inhibition of energy metabolism.

Since the survival of lymphoma patients who experience disease progression or relapse remains very poor, new therapeutic approaches and effective drugs are urgently needed. Here we show that auranofin (AF), an anti-rheumatoid drug thought to inhibit thioredoxin reductases (TXNRDs) as its mechanism of action, exhibited potent activity against multiple cancer types, especially effective against B cell lymphoma. Surprisingly, a knockdown of TXNRD1 and TXNRD2 did not cause significant cytotoxicity, suggesting that abrogation of TXNRD enzyme per se was insufficient to cause cancer cell death. Further mechanistic study showed that the interaction of AF with TXNRD could convert this antioxidant enzyme to a ROS-generating molecule via disrupting its electron transport, leading to a leak of electrons that interact with molecular oxygen to form superoxide. AF also suppressed energy metabolism by inhibiting both mitochondria complex II and the glycolytic enzyme GAPDH, leading to a significant depletion of ATP and inhibition of cancer growth in vitro and in vivo. Importantly, we found that the AF-mediated ROS stress could induce PD-L1 expression, revealing an unwanted effect of AF in causing immune suppression. We further showed that a combination of AF with anti-PD-1 antibody could enhance the anticancer activity in a syngeneic immune-competent mouse B-cell lymphoma model. Our study suggests that AF could be a potential drug for lymphoma treatment, and its combination with immune checkpoint inhibitors would be a logical strategy to increase the therapeutic activity.

Txnrd2 Attenuates Early Brain Injury by Inhibition of Oxidative Stress and Endoplasmic Reticulum Stress via Trx2/Prx3 Pathway after Intracerebral Hemorrhage in Rats.

Thioredoxin-reductase 2 (Txnrd2) belongs to the thioredoxin-reductase family of selenoproteins and is a key antioxidant enzyme in mammalian cells to regulate redox homeostasis. Here, we reported that Txnrd2 exerted a major influence in brain damage caused by Intracerebral hemorrhage (ICH) by suppressing endoplasmic reticulum (ER) stress oxidative stress and via Trx2/Prx3 pathway. Furthermore, we demonstrated that pharmacological selenium (Se) rescued the brain damage after ICH by enhancing Txnrd2 expression. Primarily, expression and localization of Txnrd2, Trx2 and Prx3 were determined in collagenase IV-induced ICH model. Txnrd2 was then knocked down using siRNA interference in rats which were found to develop more severe encephaledema and neurological deficits. Mechanistically, we observed that loss of Txnrd2 leads to increased lipid peroxidation levels and ER stress protein expression in neurons and astrocytes. Additionally, it was revealed that Se effectively restored the expression of Txnrd2 in brain and inhibited both the activity of ER stress protein activity and the generation of reactive oxygen species (ROS) by promoting Trx2/Prx3 kilter when administrating sodium selenite in lateral ventricle. This study shed light on the effect of Txnrd2 in regulating oxidative stress and ER stress via Trx2/Prx3 pathway upon ICH and its promising potential as an ICH therapeutic target.

Effect of different iodide intake during pregnancy and lactation on thyroid and cardiovascular function in maternal and offspring rats.

OBJECTIVE: We aimed to investigate the impact of different iodide intake during pregnancy and lactation on iodine concentration in urine and serum, fatty acid metabolism, thyroid and cardiovascular function in maternal and offspring rats. METHODS: Pregnant rats were randomly assigned to four groups: normal adult iodide intake (NAI, 7.5 µg/d), normal pregnant iodide intake (NPI, 12.5 µg/d), 5 times (5 HI, 62.5 µg/d) and 10 times higher-than-normal pregnant iodide intake (10 HI, 125 µg/d). The maternal rats were continuously administered potassium iodide until postnatal day 16 (PN16). Thyroid function was measured by enzyme-linked immunosorbent assay (ELISA). The iodine concentration in urine and serum were detected by inductively coupled plasma mass spectrometry (ICP-MS). The messenger ribonucleic acid (mRNA) expressions of Krüppel-like factor 9 (KLF9) and thioredoxin reductase 2 (Txnrd2) were measured using quantitative real-time polymerase chain reaction (RT-qPCR). Characteristic distribution of KLF9 expression and its interaction with TRß was assessed by immunohistochemical and immunofluorescence staining. Serum fatty acids were analyzed by Liquid Chromatography-Mass Spectrometry (LC-MS). Cardiac function and blood pressure were measured by echocardiography and a non-invasive tail-cuff system. RESULTS: High iodide intake (5 HI and 10 HI) during pregnancy and lactation results in increased urinary iodine concentration (UIC), serum total iodine concentration (STIC) and serum non-protein-bound iodine concentration (SNBIC) in both maternal and offspring rats, along with significantly increased FT3 and its target gene expression of KLF9. In maternal rats of both 5 HI and 10 HI groups, systolic blood pressure (SBP) was significantly higher, the increased SBP was significantly correlated with the increased UIC (r = 0.968, p = 0.002; r = 0.844, p = 0.035), KLF9 (r = 0.935, p = 0.006; r = 0.954, p = 0.003) and the decreased Txnrd2 (r = -0.909, p = 0.012; r = -0.912, p = 0.011). In maternal rats of 10 HI group, cardiac hyperfunction with increased LVEF, LVFS and decreased LVESD were observed. The increased LVEF and decreased LVESD were significantly correlated with UIC, STIC and SNBIC (r = 0.976, p = 0.001; r = 0.945, p = 0.005; r = 0.953, p = 0.003; r = -0.917, p = 0.01; r = -0.859, p = 0.028; r = -0.847, p = 0.033), LVEF, LVFS and LVESD were significant correlated with KLF9 (r = 0.950, p = 0.004; r = 0.963, p = 0.002; r = -0.990, p = 0.0002) and Txnrd2 expression (r = -0.979, p = 0.001; r = -0.915, p = 0.01; r = 0.933, p = 0.007), and the decreased LVESD was correlated with decreased epoxyeicosatrienoic acid (EET) metabolites: 5,6-EET, 8,9-DHET and 11,12-DHET (r = 0.999, p = 0.034; r = 1.000, p = 0.017; r = 1.000, p = 0.017). While in offspring rats, no significant change in SBP and cardiac function was found. STIC and SNBIC were much lower than those in maternal rats, and eicosapentaenoic acid (EPA) metabolites (9-HEPE, 15-HEPE and 14,15 DiHETE) were significantly increased. CONCLUSION: In addition to thyroid hormones, STIC, SNBIC, KLF9, Txnrd2, EET and EPA metabolites might be promising biomarkers in high iodide intake-induced thyroid and cardiovascular function.

Tremella fuciformis polysaccharides alleviates UV-provoked skin cell damage via regulation of thioredoxin interacting protein and thioredoxin reductase 2.

INTRODUCTION: Skin is exposed to a wide range of environmental risk factors including ultraviolet (UV) and all kinds of pollutants. Excessive UV exposure contributes to many disorders, such as photoaging, skin inflammation, and carcinogenesis. Previous studies have shown that Tremella fuciformis polysaccharides (TFPS) have protective effects on oxidative stress in cells, but the specific protective mechanism has not been clarified. METHODS: To determine the effects of TFPS on UV-irritated human skin, we conducted a variety of studies, including Cell Counting Kit-8 (CCK-8), trypan blue, Western blot, apoptosis assays, reactive oxygen species (ROS) detection in primary skin keratinocytes, and chronic UV-irradiated mouse model. RESULTS: We first determined that TFPS protects human skin keratinocytes against UV radiation-induced apoptosis and ROS production. Moreover, TFPS regulates thioredoxin interacting protein (TXNIP) and thioredoxin reductase 2 (TXNRD2) levels in primary skin keratinocytes for photoprotection. Last, we found that topical TFPS treatment could alleviate the UV-induced skin damage in chronic UV-irradiated mouse model. CONCLUSION: Collectively, our work indicates the beneficial role of TFPS in UV-induced skin cell damage and provides a novel therapeutic reagent to prevent or alleviate the progress of photoaging and other UV-provoked skin diseases.

Association of variants in the ATXN2 (rs7137828), FOXC1 (rs2745572) and TXNRD2 (rs35934224) genes as risk factors for primary open-angle glaucoma development in a Brazilian cohort.

BACKGROUND: Primary open-angle glaucoma (POAG), the world's main cause of irreversible blindness, is an asymptomatic and neurodegenerative disease of multifactorial etiology with ethnic and geographic disparities. Multiethnic genome-wide association studies (GWAS) identified single nucleotide variants (SNVs) in ATXN2, FOXC1, and TXNRD2 loci as risk factors for POAG pathophysiology and/or endophenotypes. The aim of this case-control study was to investigate the association of the variants rs7137828 (ATXN2), rs2745572 (FOXC1), and rs35934224 (TXNRD2), as risk factors for POAG development, additionally to rs7137828 association with glaucoma clinical parameters in a Brazilian cohort from the Southeast and South regions. METHODS: This investigation comprised 506 cases and 501 controls. Variants rs2745572 and rs35934224 were genotyped through TaqMan® assays and validated by Sanger sequencing. Variant rs7137828 was genotyped exclusively by Sanger sequencing. RESULTS: The primary research outcome revealed that the variant rs7137828 (ATXN2) was associated with an increased risk for the development of POAG in the presence of the TT genotype compared to the CC genotype (p = 0.006; Odds Ratio [OR] = 1.717; Confidence Interval [CI] 95% = 1.169-2.535). There was no significant association of rs2745572 and rs35934224 genotypes with POAG. The CT genotype of the rs7137828 was associated with the vertical cup-to-disk ratio (VCDR) (p = .023) but not with the age at diagnosis or the mean deviation. CONCLUSION: Our data indicate the rs7137828 associated with increased risk for the development of POAG and VCDR in a Brazilian cohort. If validated in additional populations, these findings may enable the development of relevant strategies for early diagnosis of glaucoma in the future.

Sulfasalazine and Chromotrope 2B reduce oxidative stress in murine bone marrow-derived mesenchymal stem cells.

BACKGROUND: With advancing age of stem cells, dysregulation of various processes at the cellular level occurs, thereby decreasing their regeneration potential. One of the changes that occurs during the aging process is the accumulation of reactive oxygen species (ROS), which accelerates the processes of cellular senescence and cell death. The aim of this study is to evaluate two antioxidant compounds; Chromotrope 2B and Sulfasalazine, for their antioxidant effects on young and old rat bone marrow mesenchymal stem cells (MSCs). METHODS AND RESULTS: Oxidative stress was induced in MSCs by 5 µM dexamethasone for 96 h and the cells were treated with Chromotrope 2B or Sulfasalazine, 50 µM each. The effects of antioxidant treatment following oxidative stress induction was evaluated by transcriptional profiling of genes involved in the oxidative stress and telomere maintenance. Expression levels of Cat, Gpx7, Sod1, Dhcr24, Idh1, and Txnrd2 were found to be increased in young MSCs (yMSCs) as a result of oxidative stress, while Duox2, Parp1, and Tert1 expression were found to be decreased as compared to the control. In old MSCs (oMSCs), the expressions of Dhcr24, Txnrd2, and Parp1 increased, while that of Duox2, Gpx7, Idh1, and Sod1 decreased following oxidative stress. In both MSC groups, Chromotrope 2B prompted decrease in the ROS generation before and after the induction of oxidative stress. In oMSCs, ROS content was significantly reduced in the Sulfasalazine treated group. CONCLUSION: Our findings suggest that both Chromotrope 2B and Sulfasalazine possess the potential to reduce the ROS content in both age groups, though the latter was found to be more potent. These compounds can be used to precondition MSCs to enhance their regenerative potential for future cell-based therapeutics.

Thioredoxin Reductase 2 Synergizes with Cytochrome c, Somatic to Alleviate Doxorubicin-Induced Oxidative Stress in Cardiomyocytes and Mouse Myocardium.

Doxorubicin (DOX) may cause multiple side effects, which include cardiotoxicity. Hence, to ascertain the impact of thioredoxin reductase 2 (TXNRD2) and cytochrome c, somatic (CYCS) on DOX-induced oxidative stress (OS) in cardiomyocytes and mouse myocardium, this study was implemented. DOX was utilized to treat cardiomyocytes and mice, and TXNRD2 and CYCS expression in cell supernatant and mouse myocardial tissues was detected. TXNRD2 and/or CYCS were overexpressed in DOX-induced cardiomyocytes and mice. In cardiomyocytes, cell viability and the levels of reactive oxygen species (ROS), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and glutathione (GSH) were measured. In mice, pathologic changes of the heart, ejection fraction (EF), fractional shortening (FS), and heart weight (HW) /tibial length (TL) ratio, and the contents of lactic dehydrogenase (LDH), creatine kinase-MB (CK-MB), and cardiac troponin I (cTnI) were analyzed. To assess the binding between TXNRD2 and CYCS, coimmunoprecipitation and glutathione S-transferase pull-down assays were performed. TXNRD2 and CYCS were downregulated in DOX-treated cardiomyocytes and mice. Mechanistically, TXNRD2 interacted with CYCS. Overexpression of TXNRD2 or CYCS augmented viability and SOD, CAT, and GSH levels but reduced ROS and MDA contents in DOX-induced cardiomyocytes, which was further facilitated by simultaneous overexpression of TXNRD2 or CYCS. Moreover, TXNRD2 or CYCS upregulation improved the pathologic changes in myocardial tissues, along with increases in EF, FS, and HW/TL ratio of the heart and SOD, CAT, and GSH levels and decreases in LDH, CK-MB, cTnI, ROS, and MDA levels. TXNRD2 coordinated with CYCS to alleviate DOX-induced OS in cardiomyocytes and mouse myocardium.

Mitochondrial TXNRD2 and ME3 Genetic Risk Scores Are Associated with Specific Primary Open-Angle Glaucoma Phenotypes.

PURPOSE: Genetic variants in regions that include the mitochondrial genes thioredoxin reductase 2 (TXNRD2) and malic enzyme 3 (ME3) are associated with primary open-angle glaucoma (POAG) in genome-wide association studies (GWASs). To assess their clinical impact, we investigated whether TXNRD2 and ME3 genetic risk scores (GRSs) are associated with specific glaucoma phenotypes. DESIGN: Cross-sectional study. PARTICIPANTS: A total of 2617 patients with POAG and 2634 control participants from the National Eye Institute Glaucoma Human Genetics Collaboration Hereditable Overall Operational Database (NEIGHBORHOOD) consortium. METHODS: All POAG-associated single nucleotide polymorphisms (SNPs) in the TXNRD2 and ME3 loci were identified using GWAS data (P < 0.05). Of these, 20 TXNRD2 and 24 ME3 SNPs were selected after adjusting for linkage disequilibrium. The correlation between SNP effect size and gene expression levels was investigated using the Gene-Tissue Expression database. Genetic risk scores were constructed for each individual using the unweighted sum of TXNRD2, ME3, and TXNRD2 + ME3 combined risk alleles. Age- and sex-adjusted odds ratios (ORs) for POAG diagnosis were calculated per decile for each GRS. Additionally, the clinical features of patients with POAG in the top 1%, 5%, and 10% of each GRS were compared with those in the bottom 1%, 5%, and 10%, respectively. MAIN OUTCOME MEASURES: Primary open-angle glaucoma OR per GRS decile, maximum treated intraocular pressure (IOP), and prevalence of paracentral visual field loss among patients with POAG with high versus low GRSs. RESULTS: A larger SNP effect size strongly correlated with higher TXNRD2 and lower ME3 expression levels (r = 0.95 and r = -0.97, respectively; P < 0.05 for both). Individuals in decile 10 of the TXNRD2 + ME3 GRS had the highest odds of POAG diagnosis (OR, 1.79 compared with decile 1; 95% confidence interval, 1.39-2.30; P < 0.001). Patients with POAG in the top 1% of the TXNRD2 GRS showed higher mean maximum treated IOP compared with the bottom 1% (19.9 mmHg vs. 15.6 mmHg; adjusted P = 0.03). Patients with POAG in the top 1% of the ME3 and TXNRD2 + ME3 GRS showed a higher prevalence of paracentral field loss than the bottom 1% (72.7% vs. 14.3% for ME3 GRS and 88.9% vs. 33.3% for TXNRD2+ME3 GRS; adjusted P = 0.03 for both). CONCLUSIONS: Patients with POAG with higher TXNRD2 and ME3 GRSs showed higher treated IOP and a greater prevalence of paracentral field loss. Functional studies exploring how these variants impact mitochondrial function in patients with glaucoma are warranted. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Selenoprotein Gene mRNA Expression Evaluation During Renal Ischemia-Reperfusion Injury in Rats and Ebselen Intervention Effects.

Effects of selenoproteins on many renal diseases have been reported. However, their role in renal ischemia-reperfusion (I/R) injury is unclear. The present study was performed to investigate the impact of ebselen and renal I/R injury on the expression of selenoproteins. Sprague-Dawley rats were pretreated with or without ebselen (10 mg/kg) through a daily single oral administration from 3 days before renal I/R surgery. RT-qPCR (real-time quantitative PCR) was performed to determine the mRNA expression of 25 selenoprotein genes in the renal tissues. The expression levels of two selenoproteins, including GPX3 (glutathione peroxidase 3) and DIO1 (iodothyronine deiodinase 1), were evaluated by Western blot or/and IHF (immunohistofluorescence) assays. Furthermore, renal function, renal damage, oxidative stress, and apoptosis were assessed. The results showed that in renal I/R injury, the mRNA levels of 15 selenoprotein genes (GPX1, GPX3, GPX4, DIO1, DIO2, TXNRD2, TXNRD3, SEPHS2, MSRB1, SELENOF, SELENOK, SELENOO, SELENOP, SELENOS, and SELENOT) were decreased, whereas those of eight selenoprotein genes (GPX2, GPX6, DIO3, TXNRD1, SELENOH, SELENOM, SELENOV, and SELENOW) were increased. I/R also induced a reduction in the expression levels of GPX3 and DIO1 proteins. In addition, our results indicated that ebselen reversed the changes in those selenoprotein genes, excluding SELENOH, SELENOM, SELENOP, and SELENOT, in renal I/R injury and alleviated I/R-induced renal dysfunction, tissue damage, oxidative stress, and apoptosis. To our knowledge, this is the first study to investigate the changes of 25 mammalian selenoprotein genes in renal I/R injury kidneys. The present study also provided more evidence for the roles of ebselen against renal I/R injury.

Lipoxin A4 attenuates MSU-crystal-induced NLRP3 inflammasome activation through suppressing Nrf2 thereby increasing TXNRD2.

Gout is a common inflammatory disease. The activation of NLRP3 inflammasome induced by monosodium urate (MSU) crystals has a critical role in gout, and its prevention is beneficial for patients. Lipoxin A4 (LXA4) is an endogenous lipoxygenase-derived eicosanoid mediator with powerful anti-inflammatory properties. However, whether LXA4 can suppress NLRP3 inflammasome activation induced by MSU crystals remains unclear. This study aimed to investigate the protective effect of LXA4 on MSU-crystal-induced NLRP3 inflammasome activation and its underlying molecular mechanisms. We found that LXA4 inhibited MSU-crystal-induced NLRP3 inflammasome activation, interleukin (IL)-1ß maturation, and pyroptosis. More specifically, LXA4 suppressed the assembly of the NLRP3 inflammasome, including oligomerization and speck formation of ASC, and ASC-NLRP3 interaction. Furthermore, LXA4 suppressed oxidative stress, the upstream events for NLRP3 inflammasome activation, as evidenced by the fact that LXA4 eliminated total reactive oxygen species (ROS) generation and alleviated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation and mitochondrial dysfunction. However, LXA4 also depressed the Nrf2 activation, a critical molecule in the antioxidant pathway, and then exerted an inhibitory impact on Klf9 expression and promotional impact on TXNRD2 expression, two molecules located downstream of Nrf2 in sequence. Knockdown of TXNRD2 reversed the LXA4-induced depression of ROS and NLRP3 inflammasome. Moreover, LXA4 alleviated joint inflammation and decreased the production of cleaved caspase-1 and matured IL-1ß in gouty arthritis rats. Taken together, our findings demonstrate that LXA4 can attenuate MSU-crystal-induced NLRP3 inflammasome activation, probably through suppressing Nrf2 activation to increase TXNRD2 expression. The present study highlights the potential of LXA4 as an attractive new gout treatment candidate.

Regulation of the molecular repertoires of oxidative stress response in the gills and olfactory organ of Atlantic salmon following infection and treatment of the parasite Neoparameoba perurans.

The present study investigated the involvement of key molecular regulators of oxidative stress in amoebic gill disease (AGD), a parasitic infestation in Atlantic salmon. In addition, the study evaluated how these molecular biomarkers responded when AGD-affected fish were exposed to a candidate chemotherapeutic peracetic acid (PAA). Atlantic salmon were experimentally infected with the parasite Neoparameoba perurans, the causative agent of AGD, by bath exposure and after 2 weeks, the fish were treated with three commercial PAA products (i.e., Perfectoxid, AquaDes and ADDIAqua) at a dose of 5 ppm. Two exposure durations were evaluated - 30 min and 60 min. Sampling was performed 24 h and 2 weeks after PAA treatment (equivalent to 2- and 4-weeks post infection). At each sampling point, the following parameters were evaluated: gross gill pathology, gill parasitic load, plasma reactive oxygen species (ROS) and total antioxidant capacity (TAC), histopathology and gene expression profiling of genes with key involvement in oxidative stress in the gills and olfactory organ. AGD did not result in systemic oxidative stress as ROS and TAC levels remained unchanged. There were no clear patterns of AGD-mediated regulation of the oxidative stress biomarkers in both the gills and olfactory organ; significant changes in the expression were mostly related to time rather than infection status. However, the expression profiles of the oxidative stress biomarkers in AGD-affected salmon, following treatment with PAA, revealed that gills and olfactory organ responded differently - upregulation was prominent in the gills while downregulation was more frequent in the olfactory organ. The expression of catalase, glutathione S-transferase and thioredoxin reductase 2 was significantly affected by the treatments, both in the gills and olfactory organ, and these alterations were influenced by the duration of exposure and PAA product type. Parasitic load in the gills did significantly increase after treatment regardless of the product and exposure duration; the parasite was undetectable in some fish treated with AquaDes for 30 mins. However, PAA treated groups for 30 min showed lower macroscopic gill scores than the infected-untreated fish. Histology disclosed the classic pathological findings such as multifocal hyperplasia and increased number of mucous cells in AGD-affected fish. Microscopic scoring of gill injuries showed that AGD-infected-PAA-treated fish had lower scores, however, an overall trend could not be established. The morphology and structural integrity of the olfactory organ were not significantly altered by parasitism or PAA treatment. Collectively, the results indicate that AGD did not affect the systemic and mucosal oxidative status of Atlantic salmon. However, such a striking profile was changed when AGD-affected fish were exposed to oxidative chemotherapeutics. Moreover, the gills and olfactory organ demonstrated distinct patterns of gene expression of oxidative stress biomarkers in AGD-infected-PAA-treated fish. Lastly, PAA treatment did not fully resolve the infection, but appeared not to worsen the mucosal health either.

Mitochondrial TrxR2 regulates metabolism and protects from metabolic disease through enhanced TCA and ETC function.

Mitochondrial dysfunction is a key driver of diabetes and other metabolic diseases. Mitochondrial redox state is highly impactful to metabolic function but the mechanism driving this is unclear. We generated a transgenic mouse which overexpressed the redox enzyme Thioredoxin Reductase 2 (TrxR2), the rate limiting enzyme in the mitochondrial thioredoxin system. We found augmentation of TrxR2 to enhance metabolism in mice under a normal diet and to increase resistance to high-fat diet induced metabolic dysfunction by both increasing glucose tolerance and decreasing fat deposition. We show this to be caused by increased mitochondrial function which is driven at least in part by enhancements to the tricarboxylic acid cycle and electron transport chain function. Our findings demonstrate a role for TrxR2 and mitochondrial thioredoxin as metabolic regulators and show a critical role for redox enzymes in controlling functionality of key mitochondrial metabolic systems.

Synthesis of mitochondria-targeted menadione cation derivatives: Inhibiting mitochondrial thioredoxin reductase (TrxR2) and inducing apoptosis in MGC-803 cells.

Menadione (VK3) is used as a powerful inducer of cellular reactive oxygen species (ROS) for many years and displays the high anti-cancer activities in vivo. Recently, the development of mitochondria-targeted drugs has been more and more appreciated. Here, the thirteen derivatives of VK3 were synthesized, which could localize in mitochondria by the triphenylphosphonium (TPP) cation or the nitrogen-based cation. The results of cytotoxicity from six human cancer cell lines showed that the targeted compounds T1-T13 displayed higher activity than VK3 with the average IC50 value around 1 µM. The results of cytotoxicity indicated that the substitutes on C-2, the linear alkyl chains on C-3 and cation moiety all could affect the cytotoxicity. The mechanistic studies showed that five representative compounds (T2, T3, T5, T8 and T13) could localize in cellular mitochondria, elicit ROS burst and collapse mitochondrial membrane potential (ΔΨm), leading to cytochrome C release and apoptosis in MGC-803 cells. Particularly, they could obviously inhibit mitochondrial thioredoxin reductase TrxR2 expression, thus leading to aggravate cellular oxidative stress.

Association analysis of variants rs35934224 in TXNRD2 and rs6478746 in LMX1B in primary angle-closure and pseudoexfoliation glaucoma.

OBJECTIVE: Previous genome-wide studies have demonstrated significant pathogenic association between variants rs35934224 within TXNRD2 and rs6478746 near LMX1B in primary open-angle glaucoma. We investigated the association between these variants in primary angle-closure glaucoma (PACG) and pseudoexfoliation glaucoma (PXG) patients of Saudi origin. METHODS: In a case-control study, DNA samples from 249 controls (135 men and 114 women), 100 PACG cases (44 men and 56 women), and 95 PXG cases (61 men and 34 women) were genotyped by TaqMan® based real-time PCR. Statistical tests were performed to evaluate genetic association with glaucoma types and related clinical indices. RESULTS: The allele frequencies of rs35934224 and rs6478746 did not show significant variation in PACG and PXG than controls, except that the rs35934224[T] allele was found to be significantly low among PXG women (0.10) as compared to controls (0.21) (odds ratio = 0.38, 95% confidence interval = 0.16-0.94, p = 0.024). Rs35934224 genotypes showed a nominal-to-borderline protective association with PACG and PXG among women in different genetic models. However, except for the over-dominant model in PACG (p = 0.0095), none of the effects survived Bonferroni's correction (p < 0.01). Rs6478746 showed no significant genotype or allelic association with PACG and PXG. Regression analysis showed no influence on disease outcome, and neither showed any correlation with intraocular pressure and cup/disk ratio in both PACG and PXG. CONCLUSIONS: Variants rs35934224 in TXNRD2 and rs6478746 near LMX1B are not associated with PACG and PXG in the Saudi cohort, but rs35934224 may confer modest protection among women. Further population-based studies are needed to validate these results.

TXNRD2 (rs35934224) CT genotype as possible protective marker for primary open-angle glaucoma in a Brazilian population.

PURPOSE: To investigate the association of the single-nucleotide polymorphism rs35934224 in the TXNRD2 gene with primary open-angle glaucoma in a Brazilian population. METHODS: This was a cross-sectional study conducted to verify the association between the rs35934224 TXNRD2 (thioredoxin reductase 2) and primary open-angle glaucoma in a population from the Northeast region of Brazil. A total of 184 individuals were enrolled, including 94 with primary open-angle glaucoma (45 men and 49 women) and 94 controls (40 men and 54 women) from the Recife Eye Institute. RESULTS: The mean age was 68.85 years for the patients with glaucoma and 68.55 years for the controls. Genomic DNA was isolated using commercially available kits, and single-nucleotide polymorphism was detected with real-time polymerase chain reaction using TaqMan probes. The studied population was in Hardy-Weinberg equilibrium. The CT genotype was associated with protection against primary open-angle glaucoma (p=0.022). CONCLUSION: Our data suggest an association between TXNRD2 gene polymorphism (rs35934224) with primary open-angle glaucoma in an admixed Brazilian po pulation. This is the first study to investigate this single-nucleo tide polymorphism in Latin American individuals with primary open-angle glaucoma.

Long-term administration of low-dose selenium nanoparticles with different sizes aggravated atherosclerotic lesions and exhibited toxicity in apolipoprotein E-deficient mice.

Exploration of long-term in vivo effects of nanomaterials, particularly those with potential biomedical applications, is quite important for better understanding and evaluating their biosafety. Selenium nanoparticles (SeNPs) has been considered as a good candidate in biomedical applications due to its high bioavailability, considerable biological activity, and low toxicity. However, its long-term biological effects and biosafety remain unknown. Our previous study demonstrated that 8-week supplementation with SeNPs (50 µg Se/kg/day) was safe and had an anti-atherosclerotic activity in apolipoprotein E-deficient (ApoE-/-) mice, a well-known animal model of atherosclerosis. As a chronic disease, atherosclerosis needs long-term drug therapy. The aim of this study is to investigate the long-term effects of SeNPs with different sizes on atherosclerotic lesions and their biosafety in ApoE-/- mice fed with a high fat diet. Unexpectedly, the results showed that 24-week administration of SeNPs even at a low dose (50 µg Se/kg/day) aggravated atherosclerotic lesions. Furthermore, SeNPs exacerbated oxidative stress by inhibiting the activities of antioxidant enzymes and the expression of antioxidant selenoenzymes. SeNPs also exacerbated hyperlipidaemia by inducing hepatic lipid metabolic disorder. In the meanwhile, SeNPs aggravated organ injury, especially liver and kidney injury. The above adverse effects of SeNPs were size dependent: SeNPs with the size of 40.4 nm showed the highest adverse effects among the SeNPs with three sizes (23.1 nm, 40.4 nm, and 86.8 nm). In conclusion, the present work shows that long-term administration of low-dose SeNPs aggravated atherosclerotic lesions by enhancing oxidative stress and hyperlipidaemia in ApoE-/- mice, indicative of cardiovascular toxicity. Moreover, long-term administration of SeNPs led to injury to liver and kidney. These results offer novel insights for better understanding the biosafety of SeNPs and other biomedical nanomaterials.

Genetic models of latent tuberculosis in mice reveal differential influence of adaptive immunity.

Studying latent Mycobacterium tuberculosis (Mtb) infection has been limited by the lack of a suitable mouse model. We discovered that transient depletion of biotin protein ligase (BPL) and thioredoxin reductase (TrxB2) results in latent infections during which Mtb cannot be detected but that relapse in a subset of mice. The immune requirements for Mtb control during latency, and the frequency of relapse, were strikingly different depending on how latency was established. TrxB2 depletion resulted in a latent infection that required adaptive immunity for control and reactivated with high frequency, whereas latent infection after BPL depletion was independent of adaptive immunity and rarely reactivated. We identified immune signatures of T cells indicative of relapse and demonstrated that BCG vaccination failed to protect mice from TB relapse. These reproducible genetic latency models allow investigation of the host immunological determinants that control the latent state and offer opportunities to evaluate therapeutic strategies in settings that mimic aspects of latency and TB relapse in humans.