Oxidized thioredoxin 1 places a leash on NLRP1 inflammasome activity.

The biology of the NACHT domain and leucine-rich repeat (NLR) and pyrin domain-containing 1 (NLRP1) inflammasome has perplexed researchers since this inflammasome was first described about two decades ago. The identification of oxidized thioredoxin 1 (TRX1) as a suppressor of NLRP1 recently linked cellular redox homeostasis to NLRP1 inflammasome signaling. Now, Zhang et al. present a molecular structure of TRX1-bound NLRP1 with unprecedented detail. This structure gives key insight into regulatory mechanisms governing NLRP1 activation and offers enormous potential for structure-based anti-inflammatory drug design.

Middle-age abolishes cardioprotection conferred by thioredoxin-1 in mice.

Thioredoxin-1 (Trx1) has cardioprotective effects on ischemia/reperfusion (I/R) injury, although its role in ischemic postconditioning (PostC) in middle-aged mice is not understood. This study aimed to evaluate if combining two cardioprotective strategies, such as Trx1 overexpression and PostC, could exert a synergistic effect in reducing infarct size in middle-aged mice. Young or middle-aged wild-type mice (Wt), transgenic mice overexpressing Trx1, and dominant negative (DN-Trx1) mutant of Trx1 mice were used. Mice hearts were subjected to I/R or PostC protocol. Infarct size, hydrogen peroxide (H2O2) production, protein nitration, Trx1 activity, mitochondrial function, and Trx1, pAkt and pGSK3ß expression were measured. PostC could not reduce infarct size even in the presence of Trx1 overexpression in middle-aged mice. This finding was accompanied by a lack of Akt and GSK3ß phosphorylation, and Trx1 expression (in Wt group). Trx1 activity was diminished and H2O2 production and protein nitration were increased in middle-age. The respiratory control rate dropped after I/R in Wt-Young and PostC restored this value, but not in middle-aged groups. Our results showed that Trx1 plays a key role in the PostC protection mechanism in young but not middle-aged mice, even in the presence of Trx1 overexpression.

Melatonin antagonizes oxidative stress-induced apoptosis in retinal ganglion cells through activating the thioredoxin-1 pathway.

This study aimed to explore the role of melatonin in oxidative stress-induced injury on retinal ganglion cells and the underlying mechanisms. The immortalized RGC-5 cells were treated with H2O2 to induce oxidative injury. Cell viability was measured by Cell Counting Kit-8, and apoptosis was determined by flow cytometry and western blot assays. Reactive oxygen species (ROS), lactate dehydrogenase (LDH), and malondialdehyde (MDA) levels were examined to evaluate oxidative stress levels. In addition, Thioredoxin-1 (Trx1) was silenced in RGC-5 cells using small interfering RNA followed by signaling pathway examination to explore the underlying mechanisms of melatonin in alleviating oxidative injury. Melatonin pre-treatment significantly alleviated H2O2-induced apoptosis in RGC-5 cells. Melatonin also markedly reversed the upregulation of cleaved-caspase 3, cleaved-caspase 9, and Bax expression and downregulation of Bcl-2 expression induced by H2O2. Further analyses presented that melatonin significantly attenuated the increase of ROS, LDH, and MDA levels in RGC-5 cells after H2O2 treatment. Melatonin also abolished the downregulated expression of Superoxide dismutase type 1, Trx1, and Thioredoxin reductase 1, and the reduced activity of thioredoxin reductase in RGC-5 cells after H2O2 treatment. Notably, Trx1 knockdown significantly mitigated the protective effect of melatonin in alleviating H2O2-induced apoptosis and oxidative stress, while administration of compound C, a common inhibitor of c-Jun N-terminal kinase (JNK) signaling, partially reversed the effect of Trx1 silencing, thereby ameliorating the apoptosis and oxidative injury induced by H2O2 in RGC-5 cells. Melatonin could significantly alleviate oxidative stress-induced injury of retinal ganglion cells via modulating Trx1-mediated JNK signaling pathway.

Protective effects of KLF4 on blood-brain barrier and oxidative stress after cerebral ischemia-reperfusion in rats through the Nrf2/Trx1 pathway.

PURPOSE: To investigate the role of KLF4 in CI/R injury and whether Nrf2/Trx1 axis acted as a downstream pathway of KLF4 to exert the protective role in blood-brain barrier destruction after CI/R. METHODS: The tMCAO rat model in vivo was constructed and received the intracerebroventricular injection of 5 µg/kg and 10 µg/kg rhKLF4 before operation. TTC, brain water content, neurological function, ELISA, behavioral tests, HE, TUNEL, and qRT-PCR were performed to detect the protective role of KLF4 on CIR. Double-fluorescence staining and western blot were performed to determine the localization and spatiotemporal expression in brain tissues. Furthermore, we also analyzed the effect of KLF4 on the blood-brain barrier (BBB) and related mechanisms in vivo and in vitro. Nrf2 inhibitor tretinoin was applied, which was intraperitoneally injected into CIR rat. Evans blue staining was conducted. In vitro OGD/R models of bEnd.3 cells were also established, and received KLF4 overexpressed transfection and 12.5 µM tretinoin incubation. The permeability of bEnd.3 cells was evaluated by TEER and FITC-dextran leakage. BBB-related factors and oxidative stress were also analyzed, respectively. The tubular ability of KLF4 on OGD/R bEnd3 cells was also evaluated. RESULTS: In vivo study confirmed that KLF4 was expressed in astrocyte, and its content increased with time. KLF4 protected against brain injury caused by cerebral ischemia-reperfusion, reduced cerebral infarction area and oxidative stress levels, and promoted the recovery of behavioral ability in rats. Simultaneously, mechanism experiments confirmed that the repair effect of KLF4 on cerebral ischemia-reperfusion injury was closely related to the Nrf2/Trx1 pathway. KLF4 exerted the neuroprotective effect through upregulating Nrf2/Trx1 pathway. Consistent with in vivo animal study, in vitro study also confirmed the effect of KLF4 on the permeability of bEnd.3 cells after OGD/R injury through Nrf2/Trx1 pathway. CONCLUSION: Collectively, KLF4 played neuroprotective role in CIR induced MCAO and OGD/R, and the beneficial effects of KLF4 was partly linked to Nrf2/Trx1 pathway.

Curdione inhibits ferroptosis in isoprenaline-induced myocardial infarction via regulating Keap1/Trx1/GPX4 signaling pathway.

Myocardial infarction (MI) is a common disease with high morbidity and mortality. Curdione is a sesquiterpenoid from Radix Curcumae. The current study is aimed to investigate the protective effect and mechanism of curdione on ferroptosis in MI. Isoproterenol (ISO) was used to induce MI injury in mice and H9c2 cells. Curdione was orally given to mice once daily for 7 days. Echocardiography, biochemical kits, and western blotting were performed on the markers of cardiac ferroptosis. Curdione at 50 and 100 mg/kg significantly alleviated ISO-induced myocardial injury. Curdione and ferrostatin-1 significantly attenuated ISO-induced H9c2 cell injury. Curdione effectively suppressed cardiac ferroptosis, evidenced by decreasing malondialdehyde and iron contents, and increasing glutathione (GSH) level, GSH peroxidase 4 (GPX4), and ferritin heavy chain 1 expression. Importantly, drug affinity responsive target stability, molecular docking, and surface plasmon resonance technologies elucidated the direct target Keap1 of curdione. Curdione disrupted the interaction between Keap1 and thioredoxin1 (Trx1) but enhanced the Trx1/GPX4 complex. In addition, curdione-derived protection against ISO-induced myocardial ferroptosis was blocked after overexpression of Keap1, while enhanced after Keap1 silence in H9c2 cells. These findings demonstrate that curdione inhibited ferroptosis in ISO-induced MI via regulating Keap1/Trx1/GPX4 signaling pathway.

The thioredoxin-1 inhibitor Txnip restrains effector T-cell and germinal center B-cell expansion.

Thioredoxin-1 (Trx1) is a vital component for cellular redox homeostasis. In T cells, Trx1 donates electrons for the de novo synthesis of deoxyribonucleotides to allow rapid cell proliferation. The Trx-interacting protein (Txnip) binds to the reduced Trx1 and inhibits its activity. However, the role of Txnip in adaptive immunity in vivo is unknown. Here, we show that absence of Txnip increased proliferation of effector T cells and GC B-cell responses in response to lymphocytic choriomeningitis virus and Qß virus-like particles, respectively, but did not affect development and homeostasis of T and B cells. While downregulation of Txnip and concomitant upregulation of Trx1 is critical for rapid T-cell expansion upon viral infection, re-expression of Txnip and consequently inhibition of Trx1 is important to restrain late T-cell expansion. Importantly, we demonstrated that T-cell receptor (TCR) engagement but not CD28 costimulation is critically required for Txnip downregulation. Thus, this study further uncovers positive and negative control of lymphocyte proliferation by the Trx1 system.

Salidroside inhibited cerebral ischemia/reperfusion-induced oxidative stress and apoptosis via Nrf2/Trx1 signaling pathway.

Cerebral ischemia reperfusion injury (CIRI) is still a serious problem threatening human health. Salidroside (SAL) is a natural phenylpropanoid glycoside compound with antioxidant, anti-inflammatory, and anti-ischemic properties. This study investigated the protective mechanism of SAL on middle cerebral artery occlusion (MCAO)- and oxygen-glucose deprivation/reoxygenation (OGD/R) model-induced CIRI via regulating the nuclear factor erythroid 2-related factor 2 (Nrf2)/thioredoxin 1 (Trx1) axis. The results indicated that SAL (50 mg/kg or 100 mg/kg, intraperitoneal injection) not only effectively alleviated infarction rate, improved histopathological changes, relieved apoptosis by strengthening the suppression of cleaved caspase-3 and Bax/Bcl-2 proteins and decreased malondialdehyde (MDA) formation, but also increased superoxide dismutase (SOD) and catalase (CAT) activities and upregulated the expressions of Nrf2 and Trx1 on MCAO-induced CIRI rats. SAL also efficiently inhibited apoptosis and decreased oxidative stress in OGD/R-stimulated PC12 cells. Furthermore, blocking the Nrf2/Trx1 pathway using tretinoin, an Nrf2 inhibitor, significantly reversed the protective effect of SAL on OGD/R-induced oxidative stress. Moreover, SAL reduced the expression of apoptosis signal-regulating kinase-1 (ASK1) and mitogen-activated protein kinase (MAPK) family proteins. These results demonstrated that SAL inhibited oxidative stress through Nrf2/Trx1 signaling pathway, and subsequently reduced CIRI-induced apoptosis by inhibiting ASK1/MAPK.

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OBJECTIVES: To observe the change in ferroptosis in hippocampal neurons after hypoxia-ischemia (HI) in neonatal rats and investigate the related mechanism based on the TXNIP/Trx-1/GPX4 signaling pathway. METHODS: Healthy neonatal Sprague-Dawley rats, aged 7 days, were randomly divided into three groups: sham-operation (n=30), hypoxic-ischemic brain damage (HIBD) (n=30) and siRNA (TXNIP siRNA) (n=12). The classic Rice-Vannucci method was used to establish a neonatal rat model of HIBD. At 6 hours, 24 hours, 72 hours, and 7 days after modeling, Western blot was used to measure the protein expression of GPX4 in the hippocampal tissue at the injured side; at 24 hours after modeling, laser speckle imaging combined with hematoxylin-eosin staining was used to determine whether the model was established successfully; NeuN/GPX4 and GFAP/GPX4 immunofluorescence staining combined with Western blot and other methods was used to measure the protein expression of GPX4 and the signal molecules TXNIP and Trx-1 in the hippocampal tissue at the injured side; the kits for determining the content of serum iron and tissue iron were used to measure the change in iron content; quantitative real-time PCR was used to measure the mRNA expression of TXNIP, Trx-1, and GPX4. RESULTS: At 6 hours, 24 hours, 72 hours, and 7 days after modeling, the HIBD group had a significantly lower protein expression level of GPX4 than the sham-operation group (P<0.05). At 24 hours after modeling, the HIBD group had a significantly lower cerebral blood flow of the injured side than the sham-operation group (P<0.05), with loose and disordered arrangement and irregular morphology of hippocampal CA1 neurons at the injured side. Compared with the sham-operation group, the HIBD group had a significantly higher number of TXNIP+ cells and significantly lower numbers of Trx-1+ cells and NeuN+GPX4+/NeuN+ cells in the hippocampal CA1 region at the injured side (P<0.05), with almost no GFAP+GPX4+ cells in the hippocampal CA1 region. Compared with the sham-operation group, the HIBD group and the siRNA group had significantly higher levels of serum iron and tissue iron in the hippocampus at the injured side (P<0.05). Compared with the HIBD group, the siRNA group had significantly lower levels of serum iron and tissue iron in the hippocampus at the injured side (P<0.05). The HIBD group and the siRNA group had significantly higher mRNA and protein expression levels of TXNIP than the sham-operation group (P<0.05), and the siRNA group had significantly lower expression levels than the HIBD group (P<0.05). The HIBD group and the siRNA group had significantly lower mRNA and protein expression levels of Trx-1 and GPX4 in the hippocampus at the injured side than the sham-operation group (P<0.05), and the siRNA group had significantly higher expression levels than the HIBD group (P<0.05). CONCLUSIONS: HI induces ferroptosis of hippocampal neurons in neonatal rats by activating the TXNIP/Trx-1/GPX4 pathway, thereby resulting in HIBD.

Oxidation of apoptosis-inducing factor (AIF) to disulfide-linked conjugates.

Apoptosis-inducing factor (AIF) is a flavoprotein and essential partner of the CHCHD4 redox protein during the mitochondrial intermembrane space import machinery. Mammalian AIF has three cysteine residues, which have received little attention. Previous reports have evidenced a redox interaction between AIF and thioredoxin 1 (Trx1), particularly after oxidant conditions. Therefore, we asked whether the cysteine residues of the human AIF could be oxidized. Our data showed that endogenous AIF could be oxidized to disulfide-linked conjugates (DLC). Overexpressed WT AIF in HEK293T cells, as well as recombinant WT AIF, formed DLC. Expression of C256S, C317S or C441S AIF mutants severely inhibited DLC formation in cells exposed to oxidants. In vitro, DLC formation was completely precluded with C256S and C441S AIF mutants and partially inhibited with the C317S mutant. DLC was shown to enhance cellular susceptibility to apoptosis induced by staurosporine, likely by preventing AIF to maintain mitochondrial oxidative phosphorylation. Cells with decreased expression of Trx1 produced more AIF DLC than those with normal Trx1 levels, and in vitro, Trx1 was able to decrease the amount of AIF DLC. Finally, confocal analysis, as well as immunoblotting of mitochondrial fraction, indicated that a fraction of Trx1 is present in mitochondria. Overall, these data provide evidence that all three cysteine residues of AIF can be oxidized to DLC, which can be disrupted by mitochondrial Trx1.

Regulation of hyperglycemia in diabetic mice by autolysates from ß-mannanase-treated brewer's yeast.

BACKGROUND: Diabetes mellitus is a serious chronic disease, characterized by hyperglycemia. This study administered either ß-mannanase-treated yeast cell autolysis supernatant (YCS) or yeast cell-wall residues after autolysis (YCR) to investigate their influence on the alleviation of diabetes in a diabetic mouse model. RESULTS: Application of either YCS or YCR led to body weight gain, blood glucose reduction, and an improvement in lipid composition in the diabetic mice. Administration of YCS was more effective in inhibiting oxidative stress than YCR. The expression of PPARα and CPT1α was enhanced, improving lipid biosynthesis, and Trx1 and HIF-1-α genes were downregulated due to the activation of thioredoxin following the interventions, indicating that the processes of lipid metabolism and oxidative stress were heavily involved in the reduction of diabetic characteristics following the interventions. The current study revealed that consumption of YCR also led to a reduction in hyperglycemia, this being associated with its richness in mineral elements, such as chromium and selenium. CONCLUSION: This study may highlight the potential of both YCS and YCR as functional ingredients in dietary formula for improving diabetic syndromes. © 2019 Society of Chemical Industry.

Targeting Thioredoxin System with an Organosulfur Compound, Diallyl Trisulfide (DATS), Attenuates Progression and Metastasis of Triple-Negative Breast Cancer (TNBC).

BACKGROUND/AIMS: Metastasis is the leading cause resulting in high mortality in triple negative breast cancer (TNBC) patients. Cancer cells are skilled at utilizing thioredoxin (Trx) system as an efficient antioxidant system to counteract oxidative damage, facilitating the occurrence of metastasis. Here, we identified an organosulfur compound named DATS isolated from garlic, that inhibits the expression of Trx-1 and the enzyme activity of Trx reductase in breast cancer cells. METHODS: Tissue microarray of breast cancer patients and immunohistochemical method were used to analyze the role of Trx-1 in breast cancer metastasis. Spotaneous metastasis model and experimental metastasis model combined with HE staining, immunohistochemistry were used to verify in vivo anti-metastatic effect of DATS as well as its regulation on thioredoxin. Western blot, immunofluorescence, redox state assessment and detection of enzyme activity were employed to determine the effect of DATS on thioredoxin system. Trx-1 siRNA interference was used to investigate the conclusive evidence that Trx-1 was the target of DATS. RESULTS: In agreement with reduced Trx-1 nuclear translocation from cytoplasm by DATS, the production of reduced form of Trx-1 was dramatically decreased. Furthermore, in vivo, DATS administration was observed to significantly suppress spontaneous and experimental metastasis in nude mice. Delivery of DATS also resulted in decreased expression of Trx-1 as the direct target, as well as expression of NF-κB and MMP2/9 in primary tumor and lung tissue. Notably, the effects of DATS on the expression of downstream metastasis-associated genes were mediated by Trx-1, as demonstrated by the combination use of DATS and Trx-1 siRNA. CONCLUSION: Collectively, this present study indicates that targeting Trx system with DATS may provide a promising strategy for treating metastasis of TNBC.

Sevoflurane preconditioning induces tolerance to brain ischemia partially via inhibiting thioredoxin-1 nitration.

BACKGROUND: Sevoflurane preconditioning induces brain ischemic tolerance, but the mechanism remains poorly elucidated. Nitration is an important form of post-translational modification in pathological signaling. This study was to investigate the role of thioredoxin-1 (Trx-1) nitration in neuroprotection effect induced by sevoflurane preconditioning in a transient stroke model in rats. METHODS: Adult male Sprague-Dawley rats were preconditioned with 2% sevoflurane or vehicle oxygen exposure, 1 h per day, for 5 consecutive days. At 24 h after the last exposure, rats were subjected to focal brain ischemia induced by middle cerebral artery occlusion (MCAO) for 90 min, followed by 72-h reperfusion. Trx-1 expression and activity, as well as the content of nitrotyrosine at penumbra were detected at 24 h after preconditioning and 2, 8, 24, 72 h after MCAO. Nitrated Trx-1 was examined by immunoprecipitation at 8 h after MCAO. The role of Trx-1 nitration in ischemic tolerance was assessed by administration of nitrated human-Trx-1 prior to MCAO. Neurological scores, brain infarct volumes and TUNEL staining were evaluated at 24 h after reperfusion. RESULTS: Ischemic stroke decreased Trx-1 activity but not the expression in penumbra tissue. The content of nitrotyrosine was elevated after MCAO. Preconditioning with sevoflurane increased Trx-1 activity and reduced its nitration at 8 h after MCAO in comparison with vehicle preconditioning. The decrement of Trx-1 activity was correlated with its nitration level. Exogenous administration of nitrated human-Trx-1 reversed the brain ischemic tolerance of sevoflurane preconditioning, exacerbating brain infarct volume, neurobehavioral defects and apoptosis, while administration of human-Trx-1 had no effect on the sevoflurane preconditioning-induced neuroprotection. CONCLUSION: Ischemic stroke reduces Trx-1 activity via post-translational nitrative modulation in rats. Sevoflurane preconditioning induces brain ischemic tolerance and anti-apoptosis by partially preserving Trx-1 activity via inhibiting nitration.

Silencing thioredoxin1 exacerbates damage of astrocytes exposed to OGD/R by aggravating apoptosis through the Actin-Ras2-cAMP-PKA pathway.

PURPOSE OF THE STUDY: Induction of endogenous antioxidants is one of the key molecular mechanisms of cell resistance to hypoxia/ischemia. Thioredoxin1 (Trx1) is a small multifunctional ubiquitous antioxidant with redox-active dithiol and plays an important role in cell apoptosis through mitochondrial apoptosis pathways. The specific role of Trx1 in ischemia-reperfusion induced astrocyte apoptosis, however, remains unclear. MATERIALS AND METHODS: In this study, we investigated the effect of Trx1 on apoptosis of astrocyte using an in vitro oxygen-glucose deprivation/reoxygenation (OGD/R) model which mimics ischemic/reperfusion conditions in vivo. The astrocytes prepared from newborn Sprague-Dawley rats were exposed to OGD for 4 h followed by reoxygenation for 24 h. Next, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was used to assess cell viability while cell damage was assessed by lactate dehydrogenase (LDH). RESULTS: We found that OGD/R increased cell death as well as the expression of Trx1 and that the interference of Trx1 further aggravated astrocyte damage under OGD/R condition. Furthermore, we detected an increase in the intracellular expressions of Ras2, cAMP, and PKA under OGD/R condition, which paralleled cell injury. CONCLUSIONS: Notably, the deletion of Trx1 exacerbated astrocyte apoptosis via the Ras2-cAMP-PKA signaling pathway. We concluded that Trx1 protects astrocytes against apoptotic injury induced by OGD/R, and this protective effect may be partly related to the Ras2-cAMP-PKA signaling pathway.

Diallyl trisulfides, a natural histone deacetylase inhibitor, attenuate HIF-1α synthesis, and decreases breast cancer metastasis.

Intratumoral hypoxia promotes the distant metastasis of cancer subclones. The clinical expression level of hypoxia-inducible factor-1α (HIF-1α) reflects the prognosis of a variety of cancers, especially breast cancer. Histone deacetylase (HDAC) inhibitors can target HIF-1α protein due to von Hippel-Lindau (VHL) protein-dependent degradation. Dietary organosulfur compounds, such as those in garlic, have been reported as HDAC inhibitors. The effects of diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS) on the ratio of firefly/Renilla luciferase activity in hypoxic MDA-MB-231 cells were determined. The mRNA expressions of HIF-1α target genes ANGPTL4, LOXL4, and LOX in hypoxic MDA-MB-231 cells were significantly down-regulated by DATS. DATS attenuated the metastatic potential of MDA-MB-231 cells in hypoxia-induced embryonic zebrafish, xenograft, and orthotopic tumors. Endothelial cell-cancer cell adhesion, wound healing, transwell, and tube formation assays showed that DATS dose-dependently inhibited the migration and angiogenesis of MDA-MB-231 cells in vitro. The expressions of L1CAM, VEGF-A, and EMT-related proteins (Slug, Snail, MMP-2) were inhibited by DATS. DATS dose-dependently inhibited HIF-1α transcriptional activity and hypoxia-induced hematogenous metastasis of MDA-MB-231 cells. It reduced the protein expression of HIF-1α, which did not involve inhibition of HIF-1α mRNA expression or ubiquitin proteasome degradation. Efficient inhibition of HIF-1α expression was required for DATS to resist breast cancer.

Regulation of Signal Transduction by DJ-1.

The ability of DJ-1 to modulate signal transduction has significant effects on how the cell regulates normal processes such as growth, senescence, apoptosis, and autophagy to adapt to changing environmental stimuli and stresses. Perturbations of DJ-1 levels or function can disrupt the equilibrium of homeostatic signaling networks and set off cascades that play a role in the pathogenesis of conditions such as cancer and Parkinson's disease.DJ-1 plays a major role in various pathways. It mediates cell survival and proliferation by activating the extracellular signal-regulated kinase (ERK1/2) pathway and the phosphatidylinositol-3-kinase (PI3K)/Akt pathway. It attenuates cell death signaling by inhibiting apoptosis signal-regulating kinase 1 (ASK1) activation as well as by inhibiting mitogen-activated protein kinase kinase kinase 1 (MEKK1/MAP3K1) activation of downstream apoptotic cascades. It also modulates autophagy through the ERK, Akt, or the JNK/Beclin1 pathways. In addition, DJ-1 regulates the transcription of genes essential for male reproductive function, such as spermatogenesis, by relaying nuclear receptor androgen receptor (AR) signaling. In this chapter, we summarize the ways that DJ-1 regulates these pathways, focusing on how its role in signal transduction contributes to cellular homeostasis and the pathologic states that result from dysregulation.

Alterations in NO/ROS ratio and expression of Trx1 and Prdx2 in isoproterenol-induced cardiac hypertrophy.

The development of cardiac hypertrophy is a complicated process, which undergoes a transition from compensatory hypertrophy to heart failure, and the identification of new biomarkers and targets for this disease is greatly needed. Here we investigated the development of isoproterenol (ISO)-induced cardiac hypertrophy in an in vitro experimental model. After the induction of hypertrophy with ISO treatment in H9c2 cells, cell surface area, cell viability, cellular reactive oxygen species (ROS), and nitric oxide (NO) levels were tested. Our data showed that the cell viability, mitochondrial membrane potential, and NO/ROS balance varied during the development of cardiac hypertrophy in H9c2 cells. It was also found that the expression of thioredoxin1 (Trx1) and peroxiredoxin2 (Prdx2) was decreased during the cardiac hypertrophy of H9c2 cells. These results suggest a critical role for Trx1 and Prdx2 in the cardiac hypertrophy of H9c2 cells and in the transition from compensated hypertrophy to de-compensated hypertrophy in H9c2 cells, and our findings may have important implications for the management of this disease.

Thioredoxin 1 upregulates FOXO1 transcriptional activity in drug resistance in ovarian cancer cells.

Drug resistance is the major cause of failure of cancer chemotherapy in ovarian cancer. However, the molecular mechanisms on the regulation of drug resistance are not fully understood. Here we showed that Trx1 and FOXO1 were involved in paclitaxel (PTX)-induced drug resistance in ovarian cancer A2780 cells. PTX induced reactive oxygen species (ROS) and resulted in Trx1 and FOXO1 nuclear translocation. We further found that Trx1 bound to FOXO1 and enhanced FOXO1 transcriptional activity; however Trx1 C69S mutant which is barely detected in the nucleus downregulated Trx1-FOXO1 interaction and Trx1-induced FOXO1 transcriptional activation. Silencing of FOXO1 abrogated Trx1-induced drug resistance. Trx1 increased FOXO1-induced drug resistance, while Trx1 C69S mutant completely abolished the regulation of FOXO1-mediated drug resistance by Trx1. These findings provided a novel mechanism on Trx1/FOXO1 signaling in drug resistance in ovarian cancer cells.

Intake of dietary antioxidants is inversely associated with biomarkers of oxidative stress among men with prostate cancer.

Prostate cancer is the most common non-cutaneous cancer and the second leading cause of cancer-related mortality among men in the USA. Growing evidence suggests that oxidative stress is involved in the development and progression of prostate cancer. In this study, the association between antioxidants from diet and supplements and biomarkers of oxidative stress in blood (n 278), urine (n 298) and prostate tissue (n 55) were determined among men from the North Carolina-Louisiana Prostate Cancer Project. The association between antioxidant intake and oxidative stress biomarkers in blood and urine was determined using linear regression, adjusting for age, race, prostate cancer aggressiveness and smoking status. Greater antioxidant intake was found to be associated with lower urinary 8-isoprostane concentrations, with a 10% increase in antioxidant intake corresponding to an unadjusted 1·1% decrease in urinary 8-isoprostane levels (95% CI -1·7, -0·3%; P value<0·01) and an adjusted 0·6% decrease (95% CI -1·4, 0·2%; P value=0·16). In benign prostate tissue, thioredoxin 1 was inversely associated with antioxidant intake (P=0·02). No significant associations were found for other blood or urinary biomarkers or for malignant prostate tissue. These results indicate that antioxidant intake may be associated with less oxidative stress among men diagnosed with prostate cancer.

Decreased cell proliferation and higher oxidative stress in fibroblasts from Down Syndrome fetuses. Preliminary study.

Down Syndrome is the most common chromosomal disease and is also known for its decreased incidence of solid tumors and its progeroid phenotype. Cellular and systemic oxidative stress has been considered as one of the Down Syndrome phenotype causes. We correlated, in a preliminary study, the fibroblast proliferation rate and different cell proliferation key regulators, like Rcan1 and the telomere length from Down Syndrome fetuses, with their oxidative stress profile and the Ribonucleic acid and protein expression of the main antioxidant enzymes together with their activity. Increased oxidized glutathione/glutathione ratio and high peroxide production were found in our cell model. These results correlated with a distorted antioxidant shield. The messenger RNA (SOD1) and protein levels of copper/zinc superoxide dismutase were increased together with a decreased mRNA expression and protein levels of glutathione peroxidase (GPx). As a consequence the [Cu/ZnSOD/(catalase+GPx)] activity ratio increases which explains the oxidative stress generated in the cell model. In addition, the expression of thioredoxin 1 and glutaredoxin 1 is decreased. The results obtained show a decreased antioxidant phenotype that correlates with increased levels of Regulator of calcineurin 1 and attrition of telomeres, both related to oxidative stress and cell cycle impairment. Our preliminary results may explain the proneness to a progeroid phenotype.

Comparative expression of thioredoxin-1 in uterine leiomyomas and myometrium.

Uterine leiomyomas are benign tumors that develop from smooth muscle cells (SMCs). The reactive oxygen species (ROS) have been shown to be involved in the signaling pathways that stimulate proliferation of a variety of cell types. Thioredoxin-1 (TRX-1) is a redox-regulating protein, which is overexpressed in various tumors. In the present study, we investigated the expressions of TRX-1 and its related molecules in uterine leiomyomas and matched adjacent myometrium. Our results showed the expression of TRX-1 was increased in leiomyomas compared with the matched adjacent myometrium by quantitative RT-PCR and western blotting. FOXO3A expression was increased in leiomyomas compared with myometrium by western blotting. The mRNA levels of hypoxia-inducible factor-1α, cyclooxygenase-2 and cyclin D1 were increased in leiomyomas compared with the adjacent myometrium. The mRNA level of (thioredoxin-1-binding protein) TBP-2 in leiomyomas was not altered when compared with the matched adjacent myometrium. These results suggest that TRX-1 and some of its related molecules are associated with the pathogenesis of uterine leiomyomas. The identification of TRX-1 signaling pathways leading to cell proliferation points to another potential therapeutic target for treatment and/or prevention of uterine leiomyomas.