Thioredoxin-interacting Protein Protein Research Articles

TXNIP knockdown ameliorates hepatic ischemia/reperfusion injury by inhibiting apoptosis and improving mitochondrial dysfunction via HIF-1α.

This study aims to investigate whether thioredoxin-interacting protein (TXNIP) regulates cell viability, cell apoptosis and mitochondrial damage in OGD/R-induced hepatocytes and to explore its underlying mechanism. AML12 cells were cultured under oxygen-glucose deprivation/reperfusion (OGD/R) conditions. TXNIP mRNA was detected using qRT-PCR, and the TXNIP protein was analyzed using western blotting. TXNIP-targeted short hairpin RNA (sh-TXNIP) lentivirus was used to infect the AML12 cells. CCK8 and TUNEL assays were applied to detect cell viability and apoptosis, respectively. DCFH-DA probe was used to determine reactive oxygen species (ROS) release level, and JC-1 probe was used to evaluate mitochondrial membrane potential (MMP). The localization of TXNIP and HIF-1α was observed using immunofluorescence. Our results showed that TXNIP markedly increased in AML12 cells treated with OGD/R. TXNIP knockdown increased cell viability and reduced cell apoptosis under OGD/R treatment. Moreover, MMP significantly increased and ROS release decreased in cells after TXNIP knockdown under OGD/R treatment. Additionally, TXNIP knockdown markedly increased the expression of HIF-1α. HIF-1α exhibited nuclear translocation following OGD/R induction, and TXNIP knockdown further promoted it. Compared with the OGD/R + sh-TXNIP group, HIF-1α agonist ML228 inhibited cell apoptosis and ROS release, and increased MMP. However, HIF-1α inhibitor PX478 had the opposite effect. In summary, TXNIP deletion ameliorated AML12 cell injury caused by OGD/R via promoting HIF-1α expression and nuclear translocation, manifested by inhibiting cell apoptosis and alleviating mitochondrial dysfunction.

Molecular Regulation of Transforming Growth Factor-β1-induced Thioredoxin-interacting Protein Ubiquitination and Proteasomal Degradation in Lung Fibroblasts: Implication in Pulmonary Fibrosis.

Thioredoxin-interacting protein (TXNIP) plays a critical role in regulation of cellular redox reactions and inflammatory responses by interacting with thioredoxin (TRX) or the inflammasome. The role of TXNIP in lung fibrosis and molecular regulation of its stability have not been well studied. Therefore, here we investigated the molecular regulation of TXNIP stability and its role in TGF-β1-mediated signaling in lung fibroblasts. TXNIP protein levels were significantly decreased in lung tissues from bleomycin-challenged mice. Overexpression of TXNIP attenuated transforming growth factor-β1 (TGF-β1)-induced phosphorylation of Smad2/3 and fibronectin expression in lung fibroblasts, suggesting that decrease in TXNIP may contribute to the pathogenesis of lung fibrosis. Further, we observed that TGF-β1 lowered TXNIP protein levels, while TXNIP mRNA levels were unaltered by TGF-β1 exposure. TGF-β1 induced TXNIP degradation via the ubiquitin-proteasome system. A serine residue mutant (TNXIP-S308A) was resistant to TGF-β1-induced degradation. Furthermore, downregulationof ubiquitin-specific protease-13 (USP13) promoted the TGF-β1-induced TXNIP ubiquitination and degradation. Mechanistic studies revealed that USP13 targeted and deubiquitinated TXNIP. The results of this study revealed that the decrease of TXNIP in lungs apparently contributes to the pathogenesis of pulmonary fibrosis and that USP13 can target TXNP for deubiquitination and regulate its stability.

Fluorinated curcumin derivative (Shiga-Y6) modulates the level of thioredoxin-interacting protein (TXNIP) in a mouse model of diabetes

Thioredoxin interacting protein (TXNIP) has emerged as a significant regulator of β-cell mass and loss, rendering it an attractive target for treating diabetes. We previously showed that Shiga-Y6, a fluorinated curcumin derivative, inhibited TXNIP mRNA and protein expression in vitro, raising the question of whether the same effect could be translated in vivo. Herein, we examined the effect of Shiga-Y6 on TNXIP levels and explored its therapeutic potential in a mouse model of diabetes, Akita mice. We intraperitoneally injected Shiga-Y6 (SY6; 30 mg/kg of body weight) or vehicle into 8-week-old Akita mice for 28 consecutive days. On day 29, the mice were euthanized, following which the serum levels of glucose, insulin, and glucagon were measured using ELISA, the expression of TXNIP in pancreatic tissue lysates was determined using western blotting, and the level of β-cell apoptosis was assessed using the TUNEL assay. TXNIP levels in the pancreatic tissue of Akita mice were significantly elevated compared with wild-type (WT) mice. Shiga-Y6 administration for 28 days significantly lowered those levels compared with Akita mice that received vehicle to a level comparable to WT mice. In immunohistochemical analysis, both α- to β-cell ratio and the number of apoptotic β-cells were significantly reduced in SY6-treated Akita mice, compared with vehicle-treated Akita mice. Findings from the present study suggest a potential of Shiga-Y6 as an antidiabetic agent through lowering TXNIP protein levels and ameliorating pancreatic β-cells apoptosis.

USP5 promotes lipopolysaccharide-induced apoptosis and inflammatory response by stabilizing the TXNIP protein.

The role of thioredoxin-interacting protein (TXNIP) in lipopolysaccharide-induced liver injury in mice has been reported, but the underlying mechanisms are poorly understood. We overexpressed deubiquitinase in cells overexpressing TXNIP and then detected the level of TXNIP to screen out the deubiquitinase regulating TXNIP; the interaction between TXNIP and deubiquitinase was verified by coimmunoprecipitation. After knockdown of a deubiquitinase and overexpression of TXNIP in Huh7 and HepG2 cells, lipopolysaccharide was used to establish a cellular inflammatory model to explore the role of deubiquitinase and TXNIP in hepatocyte inflammation. In this study, we discovered that ubiquitin-specific protease 5 (USP5) interacts with TXNIP and stabilizes it through deubiquitylation in Huh-7 and HepG2 cells after treatment with lipopolysaccharide. In lipopolysaccharide-treated Huh-7 and HepG2 cells, USP5 knockdown increased cell viability, reduced apoptosis, and decreased the expression of inflammatory factors, including NLRP3, IL-1β, IL-18, ASC, and procaspase-1. Overexpression of TXNIP reversed the phenotype induced by knockdown USP5. In summary, USP5 promotes lipopolysaccharide-induced apoptosis and inflammatory response by stabilizing the TXNIP protein.

0155 Persistent Activation of TXNIP and NLRP3 Inflammasomes in Cortical Glia and Neurons after Mild Traumatic Brain Injury

Abstract Introduction Mild traumatic brain injuries (TBI) induce persistent dysregulated sleep, reactive oxygen species (ROS), and inflammation. Nucleotide-binding domain leucine rich family pyrin containing 3 (NLRP3) inflammasomes are protein complexes that stimulate caspase-1 to activate the somnogenic pro-inflammatory cytokines IL-1β and IL-18. ROS induce thioredoxin interacting protein (TXNIP) to activate NLRP3 inflammasomes by inhibiting thioredoxin which inhibits ROS. We previously found that mice lacking NLRP3 have increased non-rapid-eye movement (NREM) sleep and slow-wave activity (SWA) 24 h after mild TBI, but at 2 months post-injury theses values are reduced. Following up on this, we sought to determine the activity of NLRP3 inflammasomes in glia and neurons after mild TBI. Methods Two-month-old mice lacking NLRP3, and wild-type mice received a craniectomy and mild TBI via controlled cortical impact or sham. Frontal and somatosensory cortices were collected without a TBI and at 24 h and 2 months post-TBI. Microglia, astrocytes, and neurons were isolated using fluorescent-activated cell sorting, and reactive oxygen species (ROS), RNA and protein were quantified using RT-PCR and ELISAs. Significance was set at p < 0.05. Results RNA, protein, and ROS control treatment values were similar for both genotypes in cortical microglia, astrocytes, and neurons. In wild-type mice, NLRP3, IL-1β, IL-18, caspase-1, and TXNIP expression along with ROS values were significantly greater and thioredoxin expression was significantly less in cortical microglia, astrocytes, and neurons 24 h and 2 months post-TBI. In wild-type cortical microglia, astrocytes, and neurons NLRP3, IL-1β, and TXNIP expression levels were significantly greater in these cell types 2 months vs. 24 h post-TBI. Wild-type mice caspase-1 activity and NLRP3, IL-18, IL-1β, and TXNIP protein levels, were significantly greater and thioredoxin protein levels were significantly less in both cortical areas 24 h and 2 months post-TBI. Mice lacking NLRP3 showed significant increased values of TXNIP but reduced thioredoxin expression and protein levels 24 and 2 months post-TBI but no significant differences in other measures. Conclusion Our findings suggest that TBI induces persistent oxidative stress, TXNIP, and NLRP3 inflammasome activation in cortical glia and neurons that likely contributes to sleep dysregulation. Support (if any) Merit Review Award (I01BX005379)(MRZ) and SPiRE Award (I21RX003722)(GBK) Department of Veterans Affairs

An update on the role of thioredoxin-interacting protein in diabetic kidney disease: A mini review.

Thioredoxin-interacting protein (TXNIP) was first isolated from Vitamin D3-exposed HL60 cells. TXNIP is the main redox-regulating factor in various organs and tissues. We begin with an overview of the TXNIP gene and protein information, followed by a summary of studies that have shown its expression in human kidneys. Then, we highlight our current understanding of the effect of TXNIP on diabetic kidney disease (DKD) to improve our understanding of the biological roles and signal transduction of TXNIP in DKD. Based on the recent review, the modulation of TXNIP may be considered as a new target in the management of DKD.

Regulation of Pancreatic TXNIP-Insulin Expression Levels after Bariatric Surgery Using Diabetic Rodent Model.

The purpose of this study was to investigate the effect of bariatric surgery on pancreatic thioredoxin-interacting protein (TXNIP) and insulin expression levels. The research question is does bariatric surgery induce changes in the pancreatic TXNIP level, given that TXNIP has been proposed as a key glucose control factor? Using nondiabetic and diabetic rats, we investigated whether our streptozotocin-induced diabetic rat models exhibited changes in pancreatic TXNIP regulation. Following this confirmation, we randomly divided the diabetic rats into the following three groups: the gastric bypass group (n = 16), pair-fed group (n = 10), and sham group (n = 10). Preoperatively and 3 weeks postoperatively, all the rats underwent an oral glucose tolerance test, insulin tolerance test, and blood sampling procedures for hormonal analysis. The TXNIP messenger ribonucleic acid (mRNA) and protein expression levels were significantly lower in the gastric bypass group than in the other groups. Regarding the gastric bypass group, the pancreatic mRNA expression levels of microRNA-204 (miR-204) and MafA were significantly lower and higher, respectively, than in the other groups. Furthermore, the levels of pancreatic insulin expression at the mRNA and protein levels were also significantly higher in the gastric bypass group than in the other groups. Bariatric surgery significantly improved glucose control and regulated the pancreatic insulin production pathways of TXNIP, miR-204, and MafA. The regulation of TXNIP, miR-204, and MafA might play an important role in the mechanism of diabetes remission following bariatric surgery.

In Silico Molecular Interaction Analysis and Pharmacokinetic Profiling of Flavonoids from Catharanthus roseus (Flower) Against TXNIP Protein

Catharanthus roseus is a flowering plant whose flowers have been used in traditional medicine to treat diabetes mellitus. Some of the flavonoids present in these flowers, namely, quercetin, petunidin, malvidin, kaempferol, and hirsutidin were utilized for studying molecular interaction analysis. Diabetes mellitus which is a metabolic disorder caused by the depletion in the secretion of insulin, which regulates the blood glucose levels by facilitating the metabolism of glucose. Reduction in insulin secretion is often caused by the loss of beta cells of the pancreas. Thioredoxin-interacting protein (TXNIP) is an alpha arrestin which inhibits the production of thioredoxin. It can regulate the beta cells and its inhibition can be advantageous. Reduction in insulin secretion is often caused by the loss of beta cells of the pancreas. Studies have shown that elevated levels of TXNIP can induce apoptosis in beta cells while deficiency of TXNIP leads to protection against Type I & II diabetes due to beta cell survival. To study molecular interactions, flavonoids from the flower of C. roseus and control drug glibenclamide were subjected to docking against 3D structure of TXNIP protein using Autodock 4.2 and their molecular interactions were visualized using a Biovia discovery studio visualizer. Docking interactions and ADMET studies of the bioactive compounds signified the application of C. roseus as a natural therapeutic agent to combat diabetes.
 HIGHLIGHTS
 
 Studies have shown elevated levels of TXNIP can induce apoptosis in beta cells while deficiency of TXNIP leads to protection against diabetes type I & II due to beta cell survival
 Molecular interaction analysis of flavonoids namely, quercetin, petunidin, malvidin, kaempferol, and hirsutidin from Catharanthus roseus (Flower) against TXNIP Protein were utilized for studying using Autodock 4.2 software
 ADMET study of the selected bioactive compounds were carried out
 Docking interactions and ADMET studies of the bioactive compounds signified the application of roseus as a natural therapeutic agent to combat diabetes
 
 GRAPHICAL ABSTRACT

TXNIP Exacerbates the Senescence and Aging-Related Dysfunction of β Cells by Inducing Cell Cycle Arrest Through p38-p16/p21-CDK-Rb Pathway.

Aims: Thioredoxin-interacting protein (TXNIP) is a crucial molecular promoter of oxidative stress and has been identified to be associated with cellular senescence. It is an important mediator of β cell insulin secretion and has effects on β cell mass. However, its role in β cell senescence is unclear. The present study was designed to investigate the effects and mechanisms of TXNIP on the senescence and aging- and diet-related dysfunction of β cells. Methods: Human pancreatic paraffin tissues and serum samples from different ages were collected to detect TXNIP expression. TXNIP-/- and C57BL/6J mice were fed either a normal chow diet (NCD) or a high-fat diet (HFD) until 5, 11, 14, or 20 months. The recapitulation experiment was conducted with TXNIP protein injection. MIN6 cells were transfected with LV-TXNIP and LV-siTXNIP. The biochemical indexes, ageing-related markers, cell cycle proteins, and pathways were examined both in vivo and in vitro. Results: TXNIP expression showed an age-related increase in β cells and serum samples from humans. TXNIP significantly impaired glucose metabolism and insulin secretion in an age-dependent manner. TXNIP aggravated age-related and obesity-induced structural failure, oxidative stress, decreased proliferation, increased apoptosis in β cells, and induced the cell cycle arrest. TXNIP interacted with p38 mitogen-activated protein kinase (p38MAPK) and modulated the p16/p21-CDK-Rb axis to accelerate β cell senescence. Innovation and Conclusions: The present study demonstrated that TXNIP may exacerbate pancreatic β cell senescence and age-related dysfunction by inducing cell cycle arrest through the p38-p16/p21-CDK-Rb pathway, in natural and pathological states. Antioxid. Redox Signal. 38, 480-495.

Expression and Mechanism of TXNIP/NLRP3 Inflammasome in Sciatic Nerve of Type 2 Diabetic Rats.

Objective To determine the expression profiling and mechanism of thioredoxin-interacting protein (TXNIP)/nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome pathway in sciatic nerve (SN) of type 2 diabetes mellitus (T2DM) rats. Methods Ten out of the 35 healthy SD rats (specific pathogen free) purchased were randomized into the control group, while the others were established a T2DM model by feeding a high-fat and high-sugar diet plus laparoscopic injection of 1% streptozotocin (STZ). The successfully modeled rats were subgrouped into two arms: a DM group with 10 rats and a resveratrol- (RES-) treated DM intervention group with 11 rats. Normal saline to control and DM groups. Alterations in fasting blood glucose (FBG) and body weight (BW) at different time points after administration were observed. Sciatic nerve conduction velocity (SNCV) and mechanical pain threshold (MPT) were measured. TXNIP, NLRP3, caspase-1, and interleukin- (IL-) 1β levels in rat SN tissue were determined. Results DM group rats showed higher FBG and lower BW than control rats at different time points (P < 0.05). The FBG of DM intervention group at 2, 4, and 6 weeks after administration was lower, and the BW at 4 and 6 weeks after dosing was higher than DM group. Higher MPT and SNCV were determined in DM intervention group versus DM group (P < 0.05). DM group rats had disordered, swollen, and dissolved SN myelin sheath structure; TXNIP inhibition led to a small amount of nerve myelin fragments and mild pathological changes. Lower TXNIP, NLRP3, caspase-1, and IL-1β protein levels were found in DM intervention group versus DM group (P < 0.05). Conclusion The pathogenesis of peripheral neuropathy in T2DM rats may be linked to TXNIP/NLRP3 inflammasome pathway activation, indicating the potential of this pathway as a therapeutic target for diabetic peripheral neuropathy (DPN).

3-Bromopyruvic acid regulates glucose metabolism by targeting the c-Myc/TXNIP axis and induces mitochondria-mediated apoptosis in TNBC cells.

Aerobic glycolysis is commonly observed in tumor cells, including triple-negative breast cancer (TNBC) cells, and the rate of aerobic glycolysis is higher in TNBC cells than in non-TNBC cells. Hexokinase 2 (HK2) is a key enzyme in the glycolytic pathway and a target of the transcription factor c-Myc, which is highly expressed in TNBC and promotes aerobic glycolysis by enhancing HK2 expression. As an inhibitor of HK2, 3-bromopyruvic acid (3-BrPA) exhibits good therapeutic efficacy in intrahepatic and extrahepatic tumors and inhibits the proliferation of human tumor cells with high expression levels of c-Myc in vivo and in vitro. In addition, 3-BrPA combines with photodynamic therapy to inhibit TNBC cell migration. Thioredoxin-interacting protein (TXNIP) competes with c-Myc to reduce glucose consumption in tumor cells to restrain cell proliferation. A comparative analysis was performed in the present study in TNBC (HCC1143) and non-TNBC (MCF-7) cell lines to explore the effect of 3-BrPA on energy metabolism in TNBC cells and to investigate the possible mechanism of action. Cell viability and apoptosis were detected through Cell Counting Kit-8 and flow cytometry assays, respectively. Expression levels of HK2, glucose transporter 1, TXNIP, c-Myc and mitochondria-regulated apoptosis pathway proteins were measured through western blotting. 3-BrPA inhibited cell proliferation, downregulated c-Myc and HK2 expression, and upregulated TXNIP expression in TNBC cells, but it doesn't have the same effect on non-TNBC cells. Furthermore, 3-BrPA induced the typical manifestations of mitochondrial-mediated apoptosis such as decreasing Bcl-2 expression and increasing Bax, Cyt-C and Caspase-3 expression. The present results suggested that 3-BrPA promoted TXNIP protein expression and reduced HK2 expression in TNBC cells by downregulating c-Myc expression, inhibiting glycolysis including suppressing lactate generation, intracellular ATP generation and HK activity, inducing mitochondrial-mediated apoptosis and eventually suppressing TNBC cell proliferation. These findings may reveal a novel therapeutic target for the clinical treatment of TNBC.

Localization of Thioredoxin-Interacting Protein in Aging and Alzheimer's Disease Brains.

Thioredoxin-Interacting Protein (TXNIP) has been shown to have significant pathogenic roles in many human diseases, particularly those associated with diabetes and hyperglycemia. Its main mode of action is to sequester thioredoxins, resulting in enhanced oxidative stress. The aim of this study was to identify if cellular expression of TXNIP in human aged and Alzheimer's disease (AD) brains correlated with pathological structures. This study employed fixed tissue sections and protein extracts of temporal cortex from AD and aged control brains. Studies employed light and fluorescent immunohistochemical techniques using the monoclonal antibody JY2 to TXNIP to identify cellular structures. Immunoblots were used to quantify relative amounts of TXNIP in brain protein extracts. The major finding was the identification of TXNIP immunoreactivity in selective neuronal populations and structures, particularly in non-AD brains. In AD brains, less neuronal TXNIP but increased numbers of TXNIP-positive plaque-associated microglia were observed. Immunoblot analyses showed no significant increase in levels of TXNIP protein in the AD samples tested. In conclusion, this study identified altered patterns of expression of TXNIP in human brains with progression of AD pathology.

Exercise reduces the protein abundance of TXNIP and its interacting partner REDD1 in skeletal muscle: potential role for a PKA-mediated mechanism.

Thioredoxin-interacting protein (TXNIP) negatively effects the redox state and growth signaling via its interactions with thioredoxin (TRX) and regulated in development and DNA damage response 1 (REDD1), respectively. TXNIP expression is downregulated by pathways activated during aerobic exercise (AE), via posttranslational modifications (PTMs; serine phosphorylation and ubiquitination). The purpose of this investigation was to determine the effects of acute AE on TXNIP expression, posttranslational modifications, and its interacting partners, REDD1 and TRX. Fifteen healthy adults performed 30 min of aerobic exercise (80% V̇o2max) with muscle biopsies taken before, immediately following, and 3 h following the exercise bout. To explore potential mechanisms underlying our in vivo findings, primary human myotubes were exposed to two models of exercise, electrical pulse stimulation (EPS) and palmitate-forskolin-ionomycin (PFI). Immediately following exercise, TXNIP protein decreased, but returned to preexercise levels 3 h after exercise. These results were replicated in our PFI exercise model only. Although not statistically significant, there was a trending main effect in serine-phosphorylation status of TXNIP (P = 0.07) immediately following exercise. REDD1 protein decreased 3 h after exercise. AE had no effect on TRX protein expression, gene expression, or the activity of its reducing enzyme, thioredoxin reductase. Consequently, AE had no effect on the TRX: TXNIP interaction. Our results indicate that AE leads to acute reductions in TXNIP and REDD1 protein expression. However, these changes did not result in alterations in the TRX: TXNIP interaction and could not be entirely explained by alterations in TXNIP PTMs or changes in TRX expression or activity.NEW & NOTEWORTHY Aerobic exercise is an effective tool in the prevention and treatment of several chronic metabolic diseases. However, the mechanisms through which these benefits are conferred have yet to be fully elucidated. Our data reveal a novel effect of aerobic exercise on reducing the protein expression of molecular targets that negatively impact redox and insulin/growth signaling in skeletal muscle. These findings contribute to the expanding repository of molecular signatures provoked by aerobic exercise.

YAP/miR-524-5p axis negatively regulates TXNIP expression to promote chondrosarcoma cell growth

Chondrosarcoma (CHS) is the second most common bone malignant tumor and currently has limited treatment options. We have recently demonstrated that thioredoxin interacting protein (TXNIP) plays a crucial role in the oncogenesis of bone sarcoma, yet its implication in CHS is underdetermined. In the present study, we first found that knockdown of TXNIP promotes the proliferation of CHS cell largely through increasing their glycolytic metabolism, which is well-known as Warburg effect for providing energy. Consistent with our previous report that YAP is fundamental for CHS cell growth, herein we revealed that YAP functioned as an upstream molecule of TXNIP, and that YAP negatively regulated TXNIP mRNA and protein expression both in vitro and in vivo. Mechanistically, although knockdown of YAP upregulated both the nuclear and cytoplasmic TXNIP expression, we did not observe any obvious interaction between YAP and TXNIP; instead, miRNA-524-5p was demonstrated to be required for YAP-regulated TXNIP expression and thus controlling CHS cell growth. Together, our study reveals that TXNIP is a tumor suppressor in terms of CHS, and that the YAP/miRNA-524-5p/TXNIP signaling axis may provide a novel clue for CHS targeted therapy.

MiR-223 Enhances the Neuroprotection of Estradiol Against Oxidative Stress Injury by Inhibiting the FOXO3/TXNIP Axis.

Alzheimer's disease (AD) is an irreversible neurodegenerative disorder characterized by complex pathogenesis, of which oxidative stress has long been regarded as a major mechanism. Previously, the protective effects of estradiol on SH-SY5Y cells against Aβ42-induced injuries were demonstrated. In this study, the protection of SH-SY5Y cells by estradiol from H2O2-caused oxidative stress injury and Alzheimer's mice was further confirmed. H2O2 downregulated, whereas estradiol upregulated miR-223 expression. miR-223 overexpression promoted cell viability, inhibited cell apoptosis, reduced ROS levels, enhanced Superoxide Dismutase (SOD) activity, and decreased malondialdehyde (MDA) content. However, miR-223 inhibition exerted opposite effects. miR-223 directly targeted forkhead box O3 (FOXO3) and inhibited FOXO3 expression. H2O2 increased, whereas estradiol decreased thioredoxin interacting protein (TXNIP) levels; FOXO3 positively regulated TXNIP protein levels. In SH-SY5Y cells, FOXO3 overexpression increased, whereas FOXO3 knockdown reduced the cell apoptosis and ROS levels. FOXO3 bound to TXNIP promoter region and activated TXNIP transcription, whereas the activation could be partially inhibited by estradiol. Collectively, the FOXO3/TXNIP axis is downstream of miR-223. miR-223 enhances the neuroprotection of estradiol against oxidative stress injury through the FOXO3/TXNIP axis.

A Fluorine-19 Magnetic Resonance Probe, Shiga-Y5, Downregulates Thioredoxin-Interacting Protein Expression in the Brain of a Mouse Model of Alzheimer's Disease.

Thioredoxin-interacting protein (TXNIP) is involved in multiple disease-associated functions related to oxidative stress, especially by inhibiting the anti-oxidant- and thiol-reducing activity of thioredoxin (TXN). Shiga-Y5 (SY5), a fluorine-19 magnetic resonance probe for detecting amyloid-β deposition in the brain, previously showed therapeutic effects in a mouse model of Alzheimer’s disease; however, the mechanism of action of SY5 remains unclear. SY5 passes the blood–brain barrier and then undergoes hydrolysis to produce a derivative, Shiga-Y6 (SY6), which is a TXNIP-negative regulator. Therefore, this study investigates the therapeutic role of SY5 as the prodrug of SY6 in the thioredoxin system in the brain of a mouse model of Alzheimer’s disease. The intraperitoneal injection of SY5 significantly inhibited TXNIP mRNA (p = 0.0072) and protein expression (p = 0.0143) induced in the brain of APP/PS1 mice. In contrast, the levels of TXN mRNA (p = 0.0285) and protein (p = 0.0039) in the brain of APP/PS1 mice were increased after the injection of SY5. The ratio of TXN to TXNIP, which was decreased (p = 0.0131) in the brain of APP/PS1 mice, was significantly increased (p = 0.0072) after the injection of SY5. These results suggest that SY5 acts as a prodrug of SY6 in targeting the thioredoxin system and could be a potential therapeutic compound in oxidative stress-related diseases in the brain.

TXNIP, a novel key factor to cause Schwann cell dysfunction in diabetic peripheral neuropathy, under the regulation of PI3K/Akt pathway inhibition-induced DNMT1 and DNMT3a overexpression

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes mellitus (DM) and the dysfunction of Schwann cells plays an important role in the pathogenesis of DPN. Thioredoxin-interacting protein (TXNIP) is known as an inhibitor of thioredoxin and associated with oxidative stress and inflammation. However, whether TXNIP is involved in dysfunction of Schwann cells of DPN and the exact mechanism is still not known. In this study, we first reported that TXNIP expression was significantly increased in the sciatic nerves of diabetic mice, accompanied by abnormal electrophysiological indexes and myelin sheath structure. Similarly, in vitro cultured Schwann cells TXNIP was evidently enhanced by high glucose stimulation. Again, the function experiment found that knockdown of TXNIP in high glucose-treated RSC96 cells led to a 4.12 times increase of LC3-II/LC3-I ratio and a 25.94% decrease of cleaved caspase 3/total caspase 3 ratio. Then, DNA methyltransferase (DNMT) inhibitor 5-Aza has been reported to benefit Schwann cell in DPN, and here 5-Aza treatment reduced TXNIP protein expression, improved autophagy and inhibited apoptosis in high glucose-treated RSC96 cells and the sciatic nerves of diabetic mice. Furthermore, DNMT1 and DNMT3a upregulation were found to be involved in TXNIP overexpression in high glucose-stimulated RSC96 cells. Silencing of DNMT1 and DNMT3a effectively reversed high glucose-enhanced TXNIP. Moreover, high glucose-inhibited PI3K/Akt pathway led to DNMT1, DNMT3a, and TXNIP upregulation in RSC96 cells. Knockdown of DNMT1 and DNMT3a prevented PI3K/Akt pathway inhibition-caused TXNIP upregulation in RSC96 cells. Finally, in vivo knockout of TXNIP improved nerve conduction function, increased autophagosome and LC3 expression, and decreased cleaved Caspase 3 and Bax expression in diabetic mice. Taken together, PI3K/Akt pathway inhibition mediated high glucose-induced DNMT1 and DNMT3a overexpression, leading to cell autophagy inhibition and apoptosis via TXNIP protein upregulation in Schwann cells of DPN.

Vitamin D Supplementation Induces Cardiac Remodeling in Rats: Association with Thioredoxin-Interacting Protein and Thioredoxin.

ResumoFundamento:A vitamina D (VD) tem um importante papel na função cardíaca. No entanto, a vitamina exerce uma curva “dose-resposta” bifásica na fisiopatologia cardiovascular e pode causar efeitos deletérios, mesmo em doses não tóxicas. A VD exerce suas funções celulares ligando-se ao seu receptor. Ainda, a expressão da proteína de interação com a tiorredoxina (TXNIP) é positivamente regulada pela VD. A TXNIP modula diferentes visa de sinalização celular que podem ser importantes para a remodelação cardíaca.Objetivos:Avaliar se a suplementação com VD leva à remodelação cardíaca, e se a TXNIP e a tiorredoxina (Trx) estão associadas com esse processo.Métodos:Duzentos e cinquenta ratos Wistar machos foram alocados em três grupos: controle (C, n=21), sem suplementação com VD; VD3 (n = 22) e VD10 (n=21), suplementados com 3,000 e 10,000 UI de VD/ kg de ração, respectivamente, por dois meses. Os grupos foram comparados por análise de variância (ANOVA) com um fator e teste post hoc de Holm-Sidak (variáveis com distribuição normal), ou pelo teste de Kruskal-Wallis e análise post-hoc de Dunn. O nível de significância para todos os testes foi de 5%.Resultados:A expressão de TXNIP foi mais alta e a atividade do Trx foi mais baixa no grupo VD10. Os animais que receberam suplementação com VD apresentaram aumento de hidroperóxido lipídico e diminuição de superóxido dismutase e glutationa peroxidase. A proteína Bcl-2 foi mais baixa no grupo VD10. Observou-se uma diminuição na β-oxidação de ácidos graxos, no ciclo do ácido tricarboxílico, na cadeia transportadora de elétrons, e um aumento na via glicolítica.Conclusão:A suplementação com VD levou à remodelação cardíaca e esse processo pode ser modulado por TXNIP e Trx, e consequentemente por estresse oxidativo.

Luteolin ameliorates LPS-induced acute liver injury by inhibiting TXNIP-NLRP3 inflammasome in mice

BackgroundChemical liver injury is one of the main causes of acute liver failure and death. To date, however, treatment strategies for acute liver injury have been limited. Therefore, there is an urgent need to find new therapeutic targets and effective drugs. NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome is a complex of multiple proteins that has been shown to induce cell death under inflammatory and stress pathologic conditions and is thought to provide new targets for the treatment of a variety of diseases. PurposeThe purpose of this study was to investigate whether luteolin has a protective effect on the liver and further elucidate whether it is realized through the thioredoxin interacting protein (TXNIP)-NLRP3 axis. Study designAcute hepatic injury in mice caused by intraperitoneal injection of lipopolysaccharide (LPS) was treated with or without luteolin. MethodsMale C57BL/6 mice and mouse primary hepatocytes were selected. TXNIP protein knockdown was achieved by siRNA, qPCR and Western blot were performed to explore the mechanism of luteolin in alleviating acute liver injury. ResultsThe results indicated that luteolin had a markedly protective effect on acute liver injury induced by LPS in mice by inhibiting the TXNIP-NLRP3 axis. Luteolin inhibits NLRP3 inflammasome activation by suppressing TXNIP, apoptosis associated speck-like protein containing a CARD domain (ASC), caspase-1, interleukin-1β (IL-1β) and IL-18 to reduce liver injury. In addition, luteolin inhibits LPS-induced liver inflammation by inhibiting the production of inflammation-related gene tumor necrosis factor-α (TNF-α), IL-10, and IL-6. What's more, luteolin alleviated LPS-induced hepatocyte injury by inhibiting oxidative stress and regulating MDA, SOD, and GSH levels. However, the protective effect of luteolin on acute LPS-induced liver injury in mice was blocked by si-TXNIP in vitro. ConclusionsThese combined data showed that luteolin may alleviate LPS-induced liver injury through the TXNIP-NLPR3 axis, providing new therapeutic targets and therapeutic drugs for subsequent studies.

Hsa_circ_0054633 regulates PDGF-BB-induced proliferation, migration and oxidative stress of vascular smooth muscle cells through miR-107/TXNIP axis

IntroductionHsa_circ_0054633 has been found to be elevated in the blood of coronary artery disease (CAD) patients. However, the molecular mechanism and the role of hsa_circ_0054633 in the pathogenesis of CAD have not been reported in detail.Material and methodsThe expression of hsa_circ_0054633, microRNA (miR)-107 and thioredoxin-interacting protein (TXNIP) mRNA was measured using quantitative real-time polymerase chain reaction. Human artery vascular smooth muscle cell (HA-VSMC) proliferation, cell cycle, and migration were detected by cell counting kit-8 assay, flow cytometry and transwell assay, respectively. The generation of reactive oxygen species (ROS) was analyzed by dichlorofluorescein diacetate (DCFH-DA) assay. Western blot was utilized to determine the levels of proliferating cell nuclear antigen (PCNA), cyclin D1, matrix metallopeptidase 9 (MMP-9), Mn-superoxide dismutase (SOD2) and TXNIP protein. The interaction between miR-107 and hsa_circ_0054633 or TXNIP was confirmed by dual-luciferase reporter, RNA immunoprecipitation assay or pull-down assay.ResultsHsa_circ_0054633 was elevated in the plasma of CAD patients, and might be a potential blood biomarker for CAD prediction. Hsa_circ_0054633 silencing reversed PDGF-BB-induced promotion on HA-VSMC proliferation, cell cycle, migration and ROS production. MiR-107 directly interacted with hsa_circ_0054633 and TXNIP, and hsa_circ_0054633 regulated TXNIP expression by sponging miR-107. Besides, rescue assay indicated that the action of hsa_circ_0054633 silencing on PDGF-BB-treated HA-VSMCs could be attenuated by miR-107 inhibition or TXNIP overexpression, respectively.ConclusionsHsa_circ_0054633 knockdown protected HA-VSMCs against PDGF-BB-induced dysfunction through regulating miR-107/TXNIP axis, suggesting a potential therapeutic target for coronary atherosclerosis.