Thioredoxin-interacting protein: pathophysiology and emerging pharmacotherapeutics in cardiovascular disease and diabetes

The effects of antihypertensive drugs on glucose metabolism

Abnormal glucose metabolism is a common disease of the endocrine system. The effects of drugs on glucose metabolism have been reported frequently in recent years, and since abnormal glucose metabolism increases the risk of microvascular and macrovascular complications, metabolic disorders, and infection, clinicians need to pay close attention to these effects. A variety of common drugs can affect glucose metabolism and have different mechanisms of action. Hypertension is a common chronic cardiovascular disease that requires long-term medication. Studies have shown that various antihypertensive drugs also have an impact on glucose metabolism. Among them, α-receptor blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and calcium channel blockers can improve insulin resistance, while β-receptor blockers, thiazides and loop diuretics can impair glucose metabolism. The aim of this review was to discuss the mechanisms underlying the effects of various antihypertensive drugs on glucose metabolism in order to provide reference information for rational clinical drug use.

Epigenetic Mechanisms in Sepsis-Associated Acute Kidney Injury

Sepsis, the dysregulated immune response of the host to infections, leads to numerous complications, including multiple organ dysfunction with sepsis-associated acute kidney injury (SA-AKI) being a frequent complication associated with increased risk of mortality and the progression toward chronic kidney disease (CKD). Several mechanisms have been widely investigated in understanding the complex pathophysiology of SA-AKI, including hemodynamic alterations, inflammation, oxidative stress, and direct cellular injury driven by pathogens or cell-derived products (pathogen-associated molecular patterns and damage-associated molecular patterns). Despite advancements in the management of septic patients, the prognosis of SA-AKI patients remains significantly poor and is associated with high in-hospital mortality and adverse long-term outcomes. Therefore, recent research has focused on the early identification of specific SA-AKI endotypes and subphenotypes through epigenetic analysis and the use of potential biomarkers, either alone or in combination with clinical data, to improve prognosis. Epigenetic regulation, such as DNA methylation, histone modifications, and noncoding RNA modulation, is crucial in modulating gene expression in response to stress and renal injury in SA-AKI. At the same time, these modifications are dynamic and reversible processes that can alter gene expression in several pathways implicated in the context of SA-AKI, including inflammation, immune response, and tolerance status. In addition, specific epigenetic modifications may exacerbate renal damage by causing persistent inflammation or cellular metabolic reprogramming, leading to progression toward CKD. This review aims to provide a comprehensive understanding of the epigenetic characteristics that define SA-AKI, also exploring targeted therapies that can improve patient outcomes and limit the chronic progression of this syndrome.

Mechanisms of Flavonoids and Their Derivatives in Endothelial Dysfunction Induced by Oxidative Stress in Diabetes

Diabetic complications pose a significant threat to life and have a negative impact on quality of life in individuals with diabetes. Among the various factors contributing to the development of these complications, endothelial dysfunction plays a key role. The main mechanism underlying endothelial dysfunction in diabetes is oxidative stress, which adversely affects the production and availability of nitric oxide (NO). Flavonoids, a group of phenolic compounds found in vegetables, fruits, and fungi, exhibit strong antioxidant and anti-inflammatory properties. Several studies have provided evidence to suggest that flavonoids have a protective effect on diabetic complications. This review focuses on the imbalance between reactive oxygen species and the antioxidant system, as well as the changes in endothelial factors in diabetes. Furthermore, we summarize the protective mechanisms of flavonoids and their derivatives on endothelial dysfunction in diabetes by alleviating oxidative stress and modulating other signaling pathways. Although several studies underline the positive influence of flavonoids and their derivatives on endothelial dysfunction induced by oxidative stress in diabetes, numerous aspects still require clarification, such as optimal consumption levels, bioavailability, and side effects. Consequently, further investigations are necessary to enhance our understanding of the therapeutic potential of flavonoids and their derivatives in the treatment of diabetic complications.

Disulfidptosis decoded: a journey through cell death mysteries, regulatory networks, disease paradigms and future directions

Cell death is an important part of the life cycle, serving as a foundation for both the orderly development and the maintenance of physiological equilibrium within organisms. This process is fundamental, as it eliminates senescent, impaired, or aberrant cells while also promoting tissue regeneration and immunological responses. A novel paradigm of programmed cell death, known as disulfidptosis, has recently emerged in the scientific circle. Disulfidptosis is defined as the accumulation of cystine by cancer cells with high expression of the solute carrier family 7 member 11 (SLC7A11) during glucose starvation. This accumulation causes extensive disulfide linkages between F-actins, resulting in their contraction and subsequent detachment from the cellular membrane, triggering cellular death. The RAC1-WRC axis is involved in this phenomenon. Disulfidptosis sparked growing interest due to its potential applications in a variety of pathologies, particularly oncology, neurodegenerative disorders, and metabolic anomalies. Nonetheless, the complexities of its regulatory pathways remain elusive, and its precise molecular targets have yet to be definitively identified. This manuscript aims to meticulously dissect the historical evolution, molecular underpinnings, regulatory frameworks, and potential implications of disulfidptosis in various disease contexts, illuminating its promise as a groundbreaking therapeutic pathway and target.

Thioredoxin (Trx): A redox target and modulator of cellular senescence and aging-related diseases

Thioredoxin (Trx) is a compact redox-regulatory protein that modulates cellular redox state by reducing oxidized proteins. Trx exhibits dual functionality as an antioxidant and a cofactor for diverse enzymes and transcription factors, thereby exerting influence over their activity and function. Trx has emerged as a pivotal biomarker for various diseases, particularly those associated with oxidative stress, inflammation, and aging. Recent clinical investigations have underscored the significance of Trx in disease diagnosis, treatment, and mechanistic elucidation. Despite its paramount importance, the intricate interplay between Trx and cellular senescence-a condition characterized by irreversible growth arrest induced by multiple aging stimuli-remains inadequately understood. In this review, our objective is to present a comprehensive and up-to-date overview of the structure and function of Trx, its involvement in redox signaling pathways and cellular senescence, its association with aging and age-related diseases, as well as its potential as a therapeutic target. Our review aims to elucidate the novel and extensive role of Trx in senescence while highlighting its implications for aging and age-related diseases.

TXNIP shuttling - a key molecular link in regulating inflammation and mitochondrial dysfunction in freeze tolerant wood frogs

Amphibians such as the wood frogs,Rana sylvatica, are a primary example of a freeze-tolerant vertebrate that undergoes whole body freezing. Multiple adaptations including sequestering 65-70% of total body water as extracellular/extra organ ice and producing massive amounts of glucose as a cryoprotectant support this. Interestingly, the high glucose levels induced in response to freezing can amplify oxidative stress's effects (reactive oxygen species, ROS) and induce inflammation and mitochondrial dysfunction. Since both freezing and dehydration stress (independent of freezing) can render wood frogs hyperglycemic, this study focussed on these two stresses to elucidate the role of a scaffold protein thioredoxin interacting protein (TXNIP), which localizes in multiple compartments inside the cell under hyperglycemic conditions and mediate diverse stress responses. The results from this study suggest a stress-specific response of TXNIP in inducing the cell-damaging pathway of inflammasome activation via its cytoplasmic localization during freezing. Interestingly, mitochondrial localization of TXNIP did not leads to increase in its binding to thioredoxin 2 (TRX-2) and activating the dysfunction of this organelle by releasing a mitochondrial protein cytochrome c (Cyt c) in cytoplasm under both freezing and dehydration stresses. Post-translational modifications of TXNIP hinted on changes in the regulating proteins involved in the inflammasome and mitochondrial dysfunction pathways, whereas sequential differences (cytosine residues) of amphibian TXNIP (compared to mammalian) assessed via 3D-modeling attributed to its weak binding to TRX-2. Overall, this study summarizes differential role of proteins activated under freeze and dehydration induced hyperglycemic response in freeze tolerant wood frogs.

Comparison of the efficacy of the mouse hepatic and renal antioxidant systems against inflammation-induced oxidative stress

This study was conducted to compare the efficacy of the mouse hepatic and renal antioxidant systems against inflammation-induced oxidative stress. Increased Il-1 and Il-6 expressions, markers of inflammation, were represented by inflammation models in mouse liver and kidney tissues injected intraperitoneally with LPS. After establishing the model, the GSH level and the GSH/GSSG ratio, which are oxidative stress markers, were investigated in both tissues treated with LPS and the control group. The expression of Trx1, TrxR, and Txnip genes increased in the liver tissues of LPS-treated mice. In the kidney tissue, while Trx1 expression decreased, no change was observed in TrxR1 expression, and Txnip expression increased. In the kidneys, TRXR1 and GR activities decreased, whereas GPx activity increased. In both tissues, the TRXR1 protein expression decreased significantly, while TXNIP expression increased. In conclusion, different behaviors of antioxidant system members were observed during acute inflammation in both tissues. Additionally, it can be said that the kidney tissue is more sensitive and takes earlier measures than the liver tissue against cellular damage caused by inflammation and inflammation-induced oxidative stress.

Dual Role of Extracellular Vesicles in Sepsis-Associated Kidney and Lung Injury

Extracellular vesicles form a complex intercellular communication network, shuttling a variety of proteins, lipids, and nucleic acids, including regulatory RNAs, such as microRNAs. Transfer of these molecules to target cells allows for the modulation of sets of genes and mediates multiple paracrine and endocrine actions. EVs exert broad pro-inflammatory, pro-oxidant, and pro-apoptotic effects in sepsis, mediating microvascular dysfunction and multiple organ damage. This deleterious role is well documented in sepsis-associated acute kidney injury and acute respiratory distress syndrome. On the other hand, protective effects of stem cell-derived extracellular vesicles have been reported in experimental models of sepsis. Stem cell-derived extracellular vesicles recapitulate beneficial cytoprotective, regenerative, and immunomodulatory properties of parental cells and have shown therapeutic effects in experimental models of sepsis with kidney and lung involvement. Extracellular vesicles are also likely to play a role in deranged kidney-lung crosstalk, a hallmark of sepsis, and may be key to a better understanding of shared mechanisms underlying multiple organ dysfunction. In this review, we analyze the state-of-the-art knowledge on the dual role of EVs in sepsis-associated kidney/lung injury and repair. PubMed library was searched from inception to July 2022, using a combination of medical subject headings (MeSH) and keywords related to EVs, sepsis, acute kidney injury (AKI), acute lung injury (ALI), and acute respiratory distress syndrome (ARDS). Key findings are summarized into two sections on detrimental and beneficial mechanisms of actions of EVs in kidney and lung injury, respectively. The role of EVs in kidney-lung crosstalk is then outlined. Efforts to expand knowledge on EVs may pave the way to employ them as prognostic biomarkers or therapeutic targets to prevent or reduce organ damage in sepsis.

Perhexiline Therapy in Patients with Type 2 Diabetes: Incremental Insulin Resistance despite Potentiation of Nitric Oxide Signaling

Perhexiline (Px) inhibits carnitine palmitoyltransferase 1 (CPT1), which controls uptake of long chain fatty acids into mitochondria. However, occasional cases of hypoglycaemia have been reported in Px-treated patients, raising the possibility that Px may also increase sensitivity to insulin. Furthermore, Px increases anti-aggregatory responses to nitric oxide (NO), an effect which may theoretically parallel insulin sensitization. We therefore sought to examine these relationships in patients with stable Type 2 diabetes (T2D) and cardiovascular disease (n = 30). Px was initiated, and dosage was titrated, to reach the therapeutic range and thus prevent toxicity. Investigations were performed before and after 2 weeks, to examine changes in insulin sensitivity and, utilizing aggregometry in whole blood, platelet responsiveness to the anti-aggregatory effects of the NO donor sodium nitroprusside (SNP). Other parameters that affect may affect NO signalling were also evaluated. Px substantially potentiated inhibition of platelet aggregation by SNP (from 16.7 ± 3.0 to 27.3 ± 3.7%; p = 0.005). Px did not change fasting blood glucose concentrations but reduced insulin sensitivity (HOMA-IR score increased from median of 4.47 to 6.08; p = 0.028), and increased fasting plasma insulin concentrations (median 16.5 to 19.0 mU/L; p = 0.014). Increases in SNP responses tended (r = −0.30; p = 0.11) to be reciprocally related to increases in HOMA-IR, and increases in HOMA-IR were greater (p = 0.002) in patients without NO-sensitizing effects. No patient developed symptomatic hypoglycaemia, nor was there any other short-term toxicity of Px. Thus, in patients with stable T2D and cardiovascular disease, Px increases anti-aggregatory responsiveness to NO, but is not an insulin sensitizer, and does not induce hypoglycaemia. Absence of NO-sensitizing effect occurs in approximately 30% of Px-treated patients with T2D, and is associated with induction of insulin resistance in these patients.

ITCH facilitates proteasomal degradation of TXNIP in hypoxia- induced lung cancer cells

Background

Lung cancer (LC) is one of the most common cancers and a leading cause of cancer‐related deaths worldwide. In many pathological conditions, particularly in the tumor microenvironment, cells and tissues frequently exist in a hypoxic state.

Here, we evaluated Itchy E3 ubiquitin protein ligase (ITCH) expression in LC cells following hypoxia treatment.

Methods

LC cell lines were treated with hypoxic condition. Cell migration, invasion, inflammation, reactive oxygen species (ROS) production, and apoptosis of LC cells were determined by wound healing assay, Transwell invasive assay, ELISA, DCFH‐DA staining, and flow cytometry, respectively. qPCR and WB were used to determine the expression of ITCH and TXNIP. Co‐IP was performed to assess the interaction between ITCH and TXNIP.

Results

ITCH expression was downregulated in LC cells under hypoxic conditions. Next, LC cells were subjected to hypoxic conditions and changes in cell viability and metastasis were determined. Hypoxic conditions resulted in increased migration and invasion abilities of LC cells. Intracellular reactive oxygen species (ROS) production, inflammation, and apoptosis were also promoted by hypoxia. We found that ITCH overexpression led to the proteasomal degradation of thioredoxin‐interacting protein (TXNIP), whereas the expression of the ITCH C830A mutant did not affect TXNIP levels in LC cells. The gain‐of‐function experiment demonstrated that migration, invasion, ROS generation, inflammation, and apoptosis of hypoxia‐conditioned LC cells were ameliorated by ITCH overexpression, whereas the ITCH C830A mutant did not cause any changes in these phenotypes. Furthermore, the contribution of TXNIP knockdown and ITCH overexpression to the hypoxia‐induced features in LC cells with ITCH C830A was found to be similar.

Conclusion

Our results suggest a novel mechanism underlying the changes in ITCH‐mediated malignant phenotypes of hypoxia‐conditioned LC cells via TXNIP.

Role of thioredoxin-interacting protein in mediating endothelial dysfunction in hypertension

Excessive oxidative stress is a major causative factor of endothelial dysfunction in hypertension. As an endogenous pro-oxidant, thioredoxin-interacting protein (TXNIP) contributes to oxidative damage in various tissues. The present study aimed to investigate the role of TXNIP in mediating endothelial dysfunction in hypertension. In vivo, an experimental model of acquired hypertension was established with two-kidney, one-clip (2K1C) surgery. The expression of TXNIP in the vascular endothelial cells of multiple vessels was significantly increased in hypertensive rats compared with sham-operated rats. Resveratrol, a TXNIP inhibitor, suppressed vascular oxidative damage and increased the expression and activity of eNOS in the aorta of hypertensive rats. Notably, impaired endothelium-dependent vasodilation was effectively improved by TXNIP inhibition in hypertensive rats. In vitro, we observed that Ang II increased the expression of TXNIP in primary human aortic endothelial cells (HAECs) and that TXNIP knockdown by RNA interference alleviated cellular oxidative stress damage and mitigated the impaired eNOS activation and intracellular nitric oxide (NO) production observed in Ang II-treated HAECs. However, inhibiting thioredoxin (TRX) with PX-12 completely blunted the protective effect of silencing TXNIP. In addition, TXNIP knockdown facilitated TRX expression and promoted TRX nuclear translocation to further activate AP1 and REF1. TRX overexpression exhibited favorable effects on eNOS/NO homeostasis in Ang II-treated HAECs. Thus, TXNIP contributes to oxidative stress and endothelial dysfunction in hypertension, and these effects are dependent on the antioxidant capacity of TRX, suggesting that targeting TXNIP may be a novel strategy for antihypertensive therapy.

Thioredoxin-interacting protein regulates keratinocyte differentiation: Implication of its role in psoriasis

Thioredoxin-interacting protein (TXNIP), also known as Vitamin-D upregulated protein-1 (VDUP-1), interacts with thioredoxin to regulate redox responses and participates in diverse disorders including metabolic, cardiovascular, inflammatory and malignant diseases. Psoriasis is characterized by chronic skin inflammation and an aberrant pattern of keratinocyte differentiation. Clinically, psoriasis is associated with various cardiometabolic comorbidities but studies on TXNIP's biological role in skin disorders are limited. In this study, we investigated TXNIP expression in psoriasis and its regulation in normal human epidermal keratinocytes (NHEKs), and then explored how TXNIP regulated skin keratinocyte differentiation to determine its role in psoriasis pathogenesis. Our immunohistochemical study demonstrated extensive TXNIP expression in the upper and lower epidermis of psoriasis compared to predominant TXNIP expression in the basal layer of normal skin. 1, 25-dihydroxyvitamin D₃  suppressed but TGF-α and EGF enhanced TXNIP expression in NHEKs. An inducer of keratinocyte differentiation, phorbol 12-myristate 13-acetate (PMA), also diminished TXNIP expression, which was reversed by PKC-δ knockdown. TXNIP knockdown reduced PMA-induced involucrin and transglutaminse-1 expression, and increased p63 expression in NHEKs but did not significantly affect cell proliferation. H₂ O₂ -induced ROS production and EGFR phosphorylation decreased in NHEKs with TXNIP knockdown. Furthermore, PMA-induced PKC-δ phosphorylation, TGF-α, and EGF-triggered EGFR phosphorylation were attenuated by TXNIP knockdown. Our results unraveled the regulation and function of TXNIP expression in skin keratinocytes and the cross-regulation between TXNIP and EGFR signaling. These findings imply a role of TXNIP in psoriasis and provide insight into the possible impact of TXNIP regulators on the skin or psoriasis.

Identification of a novel mechanism for reversal of doxorubicin-induced chemotherapy resistance by TXNIP in triple-negative breast cancer via promoting reactive oxygen-mediated DNA damage

Given that triple-negative breast cancer (TNBC) lacks specific receptors (estrogen and progesterone receptors and human epidermal growth factor receptor 2) and cannot be treated with endocrine therapy, chemotherapy has remained the mainstay of treatment. Drug resistance is reportedly the main obstacle to the clinical use of doxorubicin (DOX) in this patient population. Accordingly, screening molecules related to chemoresistance and studying their specific mechanisms has clinical significance for improving the efficacy of chemotherapy in TNBC patients. Thioredoxin-interacting protein (TXNIP) is a metabolism-related protein that plays a tumor suppressor role in various malignant tumors; however, the specific role of TXNIP in tumor chemoresistance has not been reported. In the present study, we explored the potential molecular mechanism of TXNIP in the chemoresistance of TNBC for the first time. The results showed that TXNIP inhibited the proliferation of TNBC drug-resistant cells and promoted apoptosis in vitro and in vivo. Furthermore, TXNIP promoted the synthesis of reactive oxygen species (ROS) and the accumulation of DNA damage caused by DOX and increased γ-H2AX levels in a time and dose-dependent manner. Moreover, ROS scavenger pretreatment could block DNA damage induced by TXNIP and restore the resistance of TNBC resistant cells to DOX to a certain extent. In addition, we found that the small molecule c-Myc inhibitor 10058-F4 promoted TXNIP expression, increased ROS synthesis in cells, and could enhance the cytotoxicity of chemotherapy drugs in vitro and in vivo when combined with DOX. These results indicated that c-Myc inhibitor 10058-F4 could induce TXNIP upregulation in TNBC drug-resistant cells, and the upregulated TXNIP increased the accumulation of ROS-dependent DNA damage, thereby decreasing chemotherapy resistance of TNBC. Our findings reveal a new mechanism of mediating drug resistance and provide a new drug combination strategy to overcome DOX resistance in TNBC.

TXNIP: A Double-Edged Sword in Disease and Therapeutic Outlook

Thioredoxin-interacting protein (TXNIP) was originally named vitamin D₃ upregulated protein-1 (VDUP1) because of its ability to bind to thioredoxin (TRX) and inhibit TRX function and expression. TXNIP is an alpha-arrestin protein that is essential for redox homeostasis in the human body. TXNIP may act as a double-edged sword in the cell. The balance of TXNIP is crucial. A study has shown that TXNIP can travel between diverse intracellular locations and bind to different proteins to play different roles under oxidative stress. The primary function of TXNIP is to induce apoptosis or pyroptosis under oxidative stress. TXNIP also inhibits proliferation and migration in cancer cells, although TXNIP levels decrease, and function diminishes in various cancers. In this review, we summarized the main structure, binding proteins, pathways, and the role of TXNIP in diseases, aiming to explore the double-edged sword role of TXNIP, and expect it to be helpful for future treatment using TXNIP as a therapeutic target.

Disrupting CISD2 function in cancer cells primarily impacts mitochondrial labile iron levels and triggers TXNIP expression

The CISD2 (NAF-1) protein plays a key role in regulating cellular homeostasis, aging, cancer and neurodegenerative diseases. It was found to control different calcium, reactive oxygen species (ROS), and iron signaling mechanisms. However, since most studies of CISD2 to date were conducted with cells that constitutively lack, overexpress, or contain mutations in CISD2, the relationships between these different signaling processes are unclear. To address the hierarchy of signaling events occurring in cells upon CISD2 disruption, we developed an inducible system to express CISD2, or the dominant-negative H114C inhibitor of CISD2, in human breast cancer cells. Here, we report that inducible disruption of CISD2 function causes an immediate disruption in mitochondrial labile iron (mLI), and that this disruption results in enhanced mitochondrial ROS (mROS) levels. We further show that alterations in cytosolic and ER calcium levels occur only after the changes in mLI and mROS levels happen and are unrelated to them. Interestingly, disrupting CISD2 function resulted in the enhanced expression of the tumor suppressor thioredoxin-interacting protein (TXNIP) that was dependent on the accumulation of mLI and associated with ferroptosis activation. CISD2 could therefore regulate the expression of TXNIP in cancer cells, and this regulation is dependent on alterations in mLI levels.

Gym and home-based combined training in men with primary hypertension: are they equally effective on functional fitness profile, body composition components, and biochemical parameters of hypertension?

OBJECTIVE

This study aimed to compare the effects of 10 weeks of gym versus home-based combined training on the functional fitness, body composition, and biochemical parameters of hypertension in primary hypertensive men.

METHODS

Forty-six patients (age 48 ± 9 years, BMI 30 ± 4 kg/m²) assigned into three groups: a gym-based combined training (GBCTr: n = 16; resistance at 60-80% of 1RM, using pin-loaded resistance equipment, aerobic at 40-60% HRR, and stretching), home-based combined training (HBCTr: n = 15; resistance at 12-15 RPE, using an elastic exercise band, aerobic at 40-60% HRR, and stretching), and control (CTR, n = 15).

RESULTS

Following GBCTr and HBCTr, the functional aerobic capacity (P = .005 and P = .004, respectively), flexibility (P = .01 and P = .004, respectively), and lower limb muscle strength (P = .01 and P = .02, respectively) was increased significantly compared with the CTR group. The body weight (P = .02), body mass index (P = .008), hip circumference (P = .02), and nitric oxide level in GBCTr and HBCTr group (P = .002 and P = .02, respectively) was decreased significantly compared with the CTR group. No significant changes found in the plasma levels of NADPH oxidase 5, thioredoxin-2, thioredoxin reductase-2, and resting blood pressure after GBCTr and HBCTr compared with the CTR group.

CONCLUSION

These results suggest that in hypertensive men, HBCTr equally to GBCTr improved functional fitness and body composition remarkably without necessarily reducing resting blood pressure. Therefore, they can be advisable substitutes for gaining health benefits.

The lncRNA CASC9 alleviates lipopolysaccharide-induced acute kidney injury by regulating the miR-424-5p/TXNIP pathway

OBJECTIVE

This study aimed to clarify the mechanism by which the long non-coding RNA cancer susceptibility candidate 9 (CASC9) alleviates sepsis-related acute kidney injury (S-AKI).

METHODS

A lipopolysaccharide (LPS)-induced AKI model was established to simulate S-AKI. HK-2 human renal tubular epithelial cells were treated with LPS to establish an in vitro model, and mice were intraperitoneally injected with LPS to generate an in vivo model. Subsequently, the mRNA expression of inflammatory and antioxidant factors was validated by quantitative reverse transcription polymerase chain reaction (RT-qPCR). Reactive oxygen species (ROS) production was assessed using an assay kit. Apoptosis was detected by western blotting and fluorescence-activated cell sorting.

RESULTS

CASC9 was significantly downregulated in the LPS-induced AKI model. CASC9 attenuated cell inflammation and apoptosis and enhanced the antioxidant capacity of cells. Regarding the mechanism, miR-424-5p was identified as the downstream target of CASC9, and the interaction between CASC9 and miR-424-5p promoted thioredoxin-interacting protein (TXNIP) expression.

CONCLUSIONS

CASC9 alleviates LPS-induced AKI in vivo and in vitro, and CASC9 directly targets miR-424-5p and further promotes the expression of TXNIP. We have provided a possible reference strategy for the treatment of S-AKI.

Up-regulation of nPKC contributes to proliferation of mice pulmonary artery smooth muscle cells in hypoxia-induced pulmonary hypertension

This study is designed to investigate the role of novel protein kinases C (nPKC) in mediating pulmonary artery smooth muscle cells (PASMCs) proliferation in pulmonary hypertension (PH) and the underlying mechanisms. Mouse PASMCs was isolated using magnetic separation technology. The PASMCs were divided into 24 h group, 48 h group and 72 h group according to different hypoxia treatment time, then detected cell proliferation rate and nPKC expression level in each group. We treated PASMCs with agonists or inhibitors of PKCdelta (PKCδ) and PKCepsilon (PKCε) and exposed them to hypoxia or normoxia for 72 h, then measured the proliferation of PASMCs. We also constructed a lentiviral vector containing siRNA fragments for inhibiting PKCδ and PKCε to transfected PASMCs, then examined their proliferation. PASMCs isolated successfully by magnetic separation method and were in good condition. Hypoxia promoted the proliferation of PASMCs, and the treatment for 72 h had the most significant effect. Hypoxia upregulated the expression of PKCδ and PKCε in mouse PASMCs, leading to PASMCs proliferation. Moreover, Our study demonstrated that hypoxia induced upregulation of PKCδ and PKCε expression resulting to the proliferation of PASMCs via up-regulating the phosphorylation of AKT and ERK. Our study provides clear evidence that increased nPKC expression contributes to PASMCs proliferation and uncovers the correlation between AKT and ERK pathways and nPKC-mediated proliferation of PASMCs. These findings may provide novel targets for molecular therapy of pulmonary hypertension.

The protective effect of the cardiac thioredoxin system on the heart in the case of iron overload in mice

BACKGROUND

Iron, which is essential for many vital biological processes, causes significant clinical pathologies in the case of its deficiency or excess. Cardiovascular protective pathways are activated by iron therapy. However, determining the appropriate iron concentration is essential to protect heart tissue from iron-induced oxidative stress. The thioredoxin system is one of the antioxidant systems that protect cells against oxidative stress. Moreover, it allows the binding of many transcription factors for apoptosis, myocardial protection, the stimulation of cell proliferation, and angiogenesis processes, especially the regulation of the cardiovascular system. This study's goal was to understand how iron overload affects the gene and protein levels of the thioredoxin system in the mouse heart.

METHODS

BALB/c mice were randomly separated into two groups. The iron overload group was administered with intraperitoneal injections of an iron-dextran solution twice a week for three weeks. In parallel, the control group was intraperitoneally given Dextran 5 solution. The total iron content, the total GSH level, the reduced glutathione/oxidized glutathione (GSH/GSSG) ratio, and thioredoxin reductase 1 (TXNRD1) activity were demonstrated spectroscopically. Changes in the iron metabolism marker genes and thioredoxin system genes were examined by qPCR. The quantitative protein expression of TXNRD1 and thioredoxin-interacting protein (TXNIP) was examined by western blotting.

RESULTS

The iron content of the heart increased in the iron overload group. The expression of hepcidin (Hamp) and ferroportin (Fpn) increased with iron overload. However, decreased expression was observed for ferritin (Fth). No changes were revealed in the GSH level and GSH/GSSG ratio. The gene expression of thioredoxin 1 (Txn1), Txnrd1, and Txnip did not change. TXNRD1 activity and protein expression increased significantly, while the protein expression of TXNIP decreased significantly.

CONCLUSION

In the case of iron overload, the cardiac thioredoxin system is affected by the protein level rather than the gene level. The amount and duration of iron overload used in this study may be considered as a starting point for further studies to determine appropriate conditions for the iron therapy of cardiovascular diseases.

Current Knowledge and Future Challenges in Takotsubo Syndrome: Part 1-Pathophysiology and Diagnosis

First recognized in 1990, takotsubo syndrome (TTS) constitutes an acute cardiac condition that mimics acute myocardial infarction commonly in the absence of obstructive coronary artery disease; it is characterized by temporary left ventricular dysfunction, regularly in a circumferential apical, midventricular, or basal distribution. Considering its acute clinical presentation, coronary angiography with left ventriculography constitutes the gold standard diagnostic tool to exclude or confirm TTS. Frequently, TTS is related to severe emotional or physical stress and a subsequent increased adrenergic stimulation affecting cardiac function. Beyond clinical presentation, epidemiology, and novel diagnostic biomarkers, this review draws attention to potential pathophysiological mechanisms for the observed reversible myocardial dysfunction such as sympathetic overdrive-mediated multi-vessel epicardial spasms, microvascular dysfunction, the direct toxicity of catecholamines, lipotoxicity, and inflammation. Considering the long-term prognosis, further experimental and clinical research is indispensable to elucidate further pathophysiological mechanisms underlying TTS before randomized control trials with evidence-based therapeutic management can be performed.

The Torpid State: Recent Advances in Metabolic Adaptations and Protective Mechanisms†

Torpor and hibernation are powerful strategies enabling animals to survive periods of low resource availability. The state of torpor results from an active and drastic reduction of an individual's metabolic rate (MR) associated with a relatively pronounced decrease in body temperature. To date, several forms of torpor have been described in all three mammalian subclasses, i.e., monotremes, marsupials, and placentals, as well as in a few avian orders. This review highlights some of the characteristics, from the whole organism down to cellular and molecular aspects, associated with the torpor phenotype. The first part of this review focuses on the specific metabolic adaptations of torpor, as it is used by many species from temperate zones. This notably includes the endocrine changes involved in fat- and food-storing hibernating species, explaining biomedical implications of MR depression. We further compare adaptive mechanisms occurring in opportunistic vs. seasonal heterotherms, such as tropical and sub-tropical species. Such comparisons bring new insights into the metabolic origins of hibernation among tropical species, including resistance mechanisms to oxidative stress. The second section of this review emphasizes the mechanisms enabling heterotherms to protect their key organs against potential threats, such as reactive oxygen species, associated with the torpid state. We notably address the mechanisms of cellular rehabilitation and protection during torpor and hibernation, with an emphasis on the brain, a central organ requiring protection during torpor and recovery. Also, a special focus is given to the role of an ubiquitous and readily-diffusing molecule, hydrogen sulfide (H2S), in protecting against ischemia-reperfusion damage in various organs over the torpor-arousal cycle and during the torpid state. We conclude that (i) the flexibility of torpor use as an adaptive strategy enables different heterothermic species to substantially suppress their energy needs during periods of severely reduced food availability, (ii) the torpor phenotype implies marked metabolic adaptations from the whole organism down to cellular and molecular levels, and (iii) the torpid state is associated with highly efficient rehabilitation and protective mechanisms ensuring the continuity of proper bodily functions. Comparison of mechanisms in monotremes and marsupials is warranted for understanding the origin and evolution of mammalian torpor.

Thioredoxin-Interacting Protein (TXNIP) with Focus on Brain and Neurodegenerative Diseases

The development of new therapeutic approaches to diseases relies on the identification of key molecular targets involved in amplifying disease processes. One such molecule is thioredoxin-interacting protein (TXNIP), also designated thioredoxin-binding protein-2 (TBP-2), a member of the α-arrestin family of proteins and a central regulator of glucose and lipid metabolism, involved in diabetes-associated vascular endothelial dysfunction and inflammation. TXNIP sequesters reduced thioredoxin (TRX), inhibiting its function, resulting in increased oxidative stress. Many different cellular stress factors regulate TXNIP expression, including high glucose, endoplasmic reticulum stress, free radicals, hypoxia, nitric oxide, insulin, and adenosine-containing molecules. TXNIP is also directly involved in inflammatory activation through its interaction with the nucleotide-binding domain, leucine-rich-containing family, and pyrin domain-containing-3 (NLRP3) inflammasome complex. Neurodegenerative diseases such as Alzheimer’s disease have significant pathologies associated with increased oxidative stress, inflammation, and vascular dysfunctions. In addition, as dysfunctions in glucose and cellular metabolism have been associated with such brain diseases, a role for TXNIP in neurodegeneration has actively been investigated. In this review, we will focus on the current state of the understanding of possible normal and pathological functions of TXNIP in the central nervous system from studies of in vitro neural cells and the brains of humans and experimental animals with reference to other studies. As TXNIP can be expressed by neurons, microglia, astrocytes, and endothelial cells, a complex pattern of regulation and function in the brain is suggested. We will examine data suggesting TXNIP as a therapeutic target for neurodegenerative diseases where further research is needed.

Upregulation of Thioredoxin-Interacting Protein in Brain of Amyloid-β Protein Precursor/Presenilin 1 Transgenic Mice and Amyloid-β Treated Neuronal Cells

Oxidative stress has been hypothesized to play a role in the pathophysiology of Alzheimer's disease (AD). Previously, we found that total nitrosylated protein levels were increased in the brain of amyloid-β protein precursor (AβPP) and presenilin 1 (PS1) double transgenic mice, an animal model for AD, suggesting that cysteine oxidative protein modification may contribute to this disease. Thioredoxin (Trx) is a major oxidoreductase that can reverse cysteine oxidative modifications such as sulfenylation and nitrosylation, and inhibit oxidative stress. Thioredoxin-interacting protein (Txnip) is an endogenous Trx inhibitor. To understand the involvement of Trx and Txnip in AD development, we investigated Trx and Txnip in the brain of AβPP/PS1 mice. Using immunoblotting analysis, we found that although Trx protein levels were not changed, Txnip protein levels were significantly increased in hippocampus and frontal cortex of 9- and 12-month-old AβPP/PS1 mice when compared to wild-type mice. Txnip protein levels were also increased by amyloid-β treatment in primary cultured mouse cerebral cortical neurons and HT22 mouse hippocampal cells. Using biotin switch and dimedone conjugation methods, we found that amyloid-β treatment increased protein nitrosylation and sulfenylation in HT22 cells. We also found that downregulation of Txnip, using CRISPR/Cas9 method in HT22 cells, attenuated amyloid-β-induced protein nitrosylation and sulfenylation. Our findings suggest that amyloid-β may increase Txnip levels, subsequently inhibiting Trx reducing capability and enhancing protein cysteine oxidative modification. Our findings also indicate that Txnip may be a potential target for the treatment of AD.

Correlation Between Thioredoxin-Interacting Protein and Nerve Conduction Velocity in Patients With Type 2 Diabetes Mellitus

Aims: To investigate the correlation between thioredoxin-interacting protein (TXNIP) and peripheral nerve conduction velocity (NCV) in patients with type 2 diabetes mellitus.

Methods: In total, 338 patients with type 2 diabetes mellitus (T2DM) were included in this study. We collected the clinical data and measured the motor conduction velocities of the bilateral ulnar nerve, median nerve, tibial nerve, and common peroneal nerve, and the sensory conduction velocities of the ulnar nerve, median nerve, sural nerve, and superficial peroneal nerve. According to the results, the patients were divided into two groups: normal peripheral nerve conduction group (NCVN group) and abnormal peripheral nerve conduction group (NCVA group). The two groups were then compared in terms of the conventional biochemical index and the sugar metabolic index as well as the serum levels of TXNIP, reduced glutathione (GSH), total superoxide dismutase (SOD), malondialdehyde (MDA), and tumor necrosis factor alpha (TNF-α). The correlation between TXNIP and NCV was also analyzed.

Results: Compared with the NCVN group, the TXNIP and MDA values were significantly increased in the NCVA group (P < 0.05). Among the patients with T2DM, age, fasting glucose, SDBG, and TXNIP were risk factors for NCV abnormality, while vitamin D3 was a protective factor. After adjusting for related confounding factors, TXNIP was significantly correlated with NCV (P < 0.05). Among the patients with T2DM, TXNIP was an independent risk factor for left ulnar motor conduction velocity (MCV), right ulnar MCV, left median MCV, and right median MCV. TNF-α was identified as a positive influencing factor for serum TXNIP, while serum TXNIP was a positive factor for TNF-α and MDA (both P < 0.05).

Conclusion: Serum TXNIP is related to NCV in T2DM patients. In combination with oxidative stress and inflammation, TXNIP may affect diabetic peripheral neuropathy (DPN).

TXNIP hypomethylation and its interaction with obesity and hypertriglyceridemia increase type 2 diabetes mellitus risk: A nested case-control study

BACKGROUND

This study aims to estimate type 2 diabetes mellitus (T2DM) incidence with DNA methylation of the thioredoxin-interacting protein (TXNIP) gene and its interaction with environmental factors.

MATERIALS AND METHODS

This case-control study included 286 incident T2DM cases and 286 non-T2DM controls matched by sex, age, marital status, race, and residence village nested in the Rural Chinese Cohort Study. A conditional logistic regression model was used to estimate the association of DNA methylation at TXNIP gene with T2DM risk. Also, multifactor dimensionality reduction (MDR) and classification and regression tree (CART) analyses were used to investigate the interaction between TXNIP methylation and environmental risk factors.

RESULTS

Methylation levels of all five CpG loci at TXNIP gene were significantly lower in T2DM than in controls (all P < .001). With increasing methylation level, risk of T2DM was significantly decreased (odds ratio, 95% CI 0.80, 0.69-0.94 for CpG1; 0.80, 0.69-0.93 for CpG2; 0.70, 0.56-0.88 for CpG3; 0.78, 0.66-0.92 for CpG4; and 0.76, 0.60-0.97 for CpG5). Additionally, the essential interactions among TXNIP methylation, obesity, and hypertriglyceridemia were identified by CART and MDR analyses. On logistic regression analysis, the risk of T2DM was reduced with terminal node 5 (CpG3 methylation ≥72%, nonobesity, normal triglyceride (TG) level, and CpG4 methylation ≥83%) vs terminal node 1 (CpG3 methylation <72%) (odds ratio 95% CI 0.20, 0.10-0.40).

CONCLUSIONS

TXNIP methylation is associated with T2DM incidence in a Chinese population. Interaction between TXNIP methylation and environmental factors may influence T2DM risk and needs more investigation.

Enhanced expression of nicotinamide nucleotide transhydrogenase (NNT) and its role in a human T cell line continuously exposed to asbestos

The effects of asbestos fibers on human immune cells have not been well documented. We have developed a continuously exposed cell line model using the human T-lymphotropic virus 1 (HTLV-1)-immortalized human T cell line MT-2. Sublines continuously exposed to chrysotile (CH) or crocidolite (CR) showed acquired resistance to asbestos-induced apoptosis following transient and high-dose re-exposure with fibers. These sublines in addition to other immune cells such as natural killer cells or cytotoxic T lymphocytes exposed to asbestos showed a reduction in anti-tumor immunity. In this study, the expression of genes and molecules related to antioxidative stress was examined. Furthermore, complexes related to oxidative phosphorylation were investigated since the production of reactive oxygen species (ROS) is important when considering the effects of asbestos in carcinogenesis and the mechanisms involved in resistance to asbestos-induced apoptosis. In sublines continuously exposed to CH or CR, the expression of thioredoxin decreased. Interestingly, nicotinamide nucleotide transhydrogenase (NNT) expression was markedly enhanced. Thus, knockdown of NNT was then performed. Although the knockdown clones did not show any changes in proliferation or occurrence of apoptosis, these clones showed recovery of ROS production with returning NADPH/NADP+ ratio that increased with decreased production of ROS in continuously exposed sublines. These results indicated that NNT is a key factor in preventing ROS-induced cytotoxicity in T cells continuously exposed to asbestos. Considering that these sublines showed a reduction in anti-tumor immunity, modification of NNT may contribute to recovery of the anti-tumor effects in asbestos-exposed T cells.

The Anti-Inflammatory Effects of Glucagon-Like Peptide Receptor Agonist Lixisenatide on the Retinal Nuclear and Nerve Fiber Layers in an Animal Model of Early Type 2 Diabetes

This study explored the anti-inflammatory effects of a glucagon-like peptide-1 receptor agonist (GLP-1RA), known as lixisenatide, on the eyes of early type 2 diabetic mice. Diabetic (db/db) mice were divided into three groups: GLP-1RA [lixisenatide (LIX)], insulin (INS) with controlled hyperglycemia based on the glucose concentration of lixisenatide, and diabetic control (D-CON). Nondiabetic control mice (db/dm) were also characterized for comparison. After 8 weeks of treatment, mRNA levels of inflammatory markers, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, immunohistochemical staining; Western blot of glial fibrillary acidic protein (GFAP) and thioredoxin-interacting protein; and retinal thickness were assessed in the central and peripheral neurosensory retina. LIX showed decreased immunohistochemical staining for both thioredoxin-interacting protein and GFAP in the central and peripheral neurosensory retina compared with D-CON and INS, and decreased expression of these proteins in the neurosensory retina and immunohistochemical staining in the optic nerve head for GFAP compared with D-CON. The inner nuclear layer in the peripheral retina in LIX was only thinner than those of D-CON and INS. In an early type 2 diabetic mouse model, lixisenatide treatment showed superior anti-inflammatory effects on the retina and optic nerve head independent of hyperglycemia. Thus, the neuroprotective effects of lixisenatide treatment in the peripheral inner nuclear layer should be evaluated in early type 2 diabetic retinopathy.

Antecedent cancer in Takotsubo syndrome predicts both cardiovascular and long-term mortality

Background

Takotsubo syndrome (TTS), primarily an acute myocardial inflammatory condition engendered by catecholamine exposure, is associated with similar long-term mortality rates to those of patients with acute myocardial infarction. However, there is increasing evidence of a nexus between TTS and underlying malignancies:- many patients have antecedent cancer (A/Ca), while incremental risk of late cancer-related death has also been reported.

Purpose

To evaluate potential interactions between A/Ca among TTS patients and both early and late clinical course.

Methods

Three hundred forty-six consecutive TTS patients [aged 69 ± 13 (SD) years, males: 8.2%] were prospectively followed up for a median duration of 4.1 (IQR 2.2–6.4) years. Associations between A/Ca and severity of acute attacks, in-hospital complications and long-term death rates were sought utilising univariate analyses followed by multiple logistic regression analysis.

Results

A/Ca (present in 16.8% of patients) was associated with (i) greater elevation of hs-CRP and NT-proBNP concentrations (p = 0.01 and 0.04, respectively), (ii) more complicated in-hospital clinical course, with major adverse cardiac events (MACE) in 30.9% of patients, compared to 18.2% in non-A/Ca patients (p = 0.04). Long-term all-cause mortality rate was also greater [hazard ratio (HR) = 2.4, p = 0.0001] in A/Ca patients, with an excess cardiovascular (CVS) fatality rate (HR = 3.1, p = 0.001). On multivariate analysis, male gender, peak plasma concentrations of normetanephrine and hs-CRP, early arrhythmias and development of shock, but not A/Ca per se, were all independently associated with increased long-term mortality rate. Furthermore, patients discharged on β-adrenoceptor antagonists (βBl) or angiotensin converting enzyme inhibitors/ angiotensin receptor blockers (ACEi/ARB) had lower long-term mortality rates (β = − 0.2, p = 0.01; β = − 0.14, p = 0.05, respectively).

Conclusions

(1) A/Ca is associated with greater clinical severity of initial TTS attacks and substantially greater long-term CVS-related as well as all-cause mortality.

(2) Post-discharge therapy with either βBl or ACEi/ARB is associated with reductions in long-term mortality rates.

Overall, the current data suggest operation of substantial interactions between neoplasia and TTS, both at the level of pathogenesis and of outcomes.

S-Equol ameliorates insulin secretion failure through Chrebp/Txnip signaling via modulating PKA/PP2A activities

Background

S-Equol, produced from daidzein by gut microbiota, has been suggested as an potential anti-diabetic agent, but the underlying mechanisms remain unclear. Recent evidences demonstrated that carbohydrate response element-binding protein (Chrebp)/Thioredoxin-interacting protein (Txnip) signaling played central roles on diabetes progression, particularly in relation to the function maintenance and apoptosis of pancreatic β-cell. Here, we investigated the effects of S-Equol on β-cell function and Chrebp/Txnip signaling.

Methods

Zucker diabetic fatty rats were treated with racemic Equol (120 mg/kg.BW.d) for 6 weeks. The glucose and lipid metabolism were monitored during the supplementation, and the Chrebp and Txnip expression were measured by using Western blotting. INS-1 cells were incubated with high glucose (26.2 mM) with or without S-Equol (0.1 μM, 1 μM, 10 μM) for 48 h. Glucose-stimulated insulin secretion (GSIS) was evaluated by radioimmunoassay, and the apoptosis of INS-1 cells was analyzed using Annexin V-FITC/PI and TUNEL assay. The dual luciferase reporter assay, chromatin immunoprecipitation assay and Western-blotting followed by Chrebp small interfering RNAs were utilized to clarify the mechanism of transcriptional regulation of S-Equol on Chrebp/Txnip signaling and the activities of protein kinase A (PKA) and protein phophatase (PP2A) were also detected.

Results

In vivo, Equol supplementation delayed the onset of the hyperglycemia and hyperlipemia, ameliorated insulin secretion failure, enhanced GSIS in isolated islets, and significantly reduced Chrebp and Txnip expression in islets. In vitro, S-Equol treatment enhanced GSIS of high glucose cultured INS-1 cell, and reduced apoptosis of INS-1 cells were also observed. Moreover, S-Equol dramatically suppressed Txnip transcription, as evident by the reduction of Txnip protein and mRNA levels and decrease in the Txnip promoter-driven luciferase activity. Meanwhile, S-Equol significantly inhibited Chrebp/Mlx expression and decreased occupancy of Chrebp on the Txnip promoter, and combined with siChrebp, we confirmed that S-Equol improvement of insulin secretion was partially through the Chrebp/Txnip pathway. Furthermore, S-Equol significantly decrease nuclear translocation of Chrebp, which was related with the decrease activity of protein kinase A (PKA) and the increase activity of protein phophatase (PP2A).

Conclusions

S-Equol could ameliorate insulin secretion failure, which was dependent on the suppression of Chrebp/Txnip signaling via modulating PKA/PP2A activities.

Thioredoxin-Interacting Protein as a Novel Potential Therapeutic Target in Diabetes Mellitus and Its Underlying Complications

Diabetes mellitus (DM) is a common metabolic disorder which is characterized by a persistent increment of blood glucose. Globally, DM affects millions of people and the prevalence is increasing alarmingly. The critical step in the pathophysiology of DM is the loss of β-cells of the pancreas, which are responsible for the secretion of insulin. Thioredoxin-interacting protein (TXNIP) is among the factors that control the production and loss of the pancreatic β-cells. TXNIP is an α-arrestin that can bind and inhibit thioredoxin (the antioxidant protein) which is produced in the pancreatic islet after glucose intake. Numerous studies illustrated that elevated TXNIP levels were found to induce β-cell apoptosis; whereas TXNIP deficiency protects against type I and type II diabetes by promoting β-cell survival. Nowadays, TXNIP depletion is becoming a key factor in pancreatic β-cell survival enhancement. In the present review, targeting TXNIP is found to be relevant as a unique therapeutic opportunity, not only to improve insulin secretion and sensitivity, but also ameliorating the long term microvascular and macrovascular complications of the disease. Thus, TXNIP inhibitors that could reduce the expression and/or activity of TXNIP to non-diabetic levels are promising agents to halt the alarming rate of diabetes and its related complications.

Thioredoxin, thioredoxin interacting protein and transducer and activator of transcription 3 in gestational diabetes

To evaluate changes in the inflammatory response of thioredoxin (TXN), thioredoxin interacting protein (TXNIP), transducer and activator of transcription 3, NFƙB-p50 and STAT3 at the level of maternal serum, placenta, and umbilical cord blood of women with gestational diabetes mellitus type 2 (GDMA2) compared to normal pregnancies (NP). Thirty pregnant women (20 with GDMA2 and 10 NP) were recruited during admission for delivery. Blood samples were obtained from the parturients and umbilical cords, as well as placental tissue for mRNA and protein extraction. TXNIP mRNA expression was significantly increased in maternal serum of women with GDMA2 compared to NP women. TXNIP mRNA was significantly decreased in GDMA2 placentas and cord blood compared to NP. TXN/TXNIP mRNA ratio showed significantly high absolute values in placental and cord blood (2.39 and 1.66) respectively, compared to maternal ratio (1.084) (P < 0.001). TXN/TXNIP placenta protein ratio showed similar values between GDMA2 and NP (0.98 and 0.86; P = 0.7). STAT3 and its target protein SOCS3, as well as NFƙB-p50 mRNA expression were significantly increased in placentas of GDMA2. NFƙB-p50 mRNA expression was significantly decreased in cord blood compared to both maternal and placental mRNA expression. Pro-inflammatory changes are expressed by low mRNA TXN/TXNIP ratio in maternal blood of GDMA2 patients, but not in placental and umbilical cord blood samples. This, as well as the feedback role of SOCS3 in STAT3 pathway and NFƙB-p50 expression, may indicate that the placenta has a role in protecting the fetus from damage due to inflammatory response, which is common in diabetes.

NLRP3 inflammasome mediates angiotensin II-induced islet β cell apoptosis

Elevation of angiotensin II (Ang II) in the serum of patients with diabetes is known to promote apoptosis of islet β cells, but the underlying mechanism remains unclear. The aim of the present study was to explore the role of Nod-like receptor protein 3 (NLRP3) inflammasome in Ang II-induced apoptosis of pancreatic islet β cells and investigate the possible underlying mechanism. The effect of Ang II on INS-1 cell (a rat insulinoma cell line) viability was detected by CCK-8 method. The cell apoptosis was detected by flow cytometry and western blot analysis. The effect of Ang II on the expressions of thioredoxin-interacting protein (TXNIP) and NLRP3 protein was detected by western blot analysis. The expression of TXNIP mRNA was detected by real-time polymerase chain reaction. The results showed that Ang II was able to reduce INS-1 cell viability and promote apoptosis and at the same time up-regulate the expressions of TXNIP and NLRP3 components. Ang II-induced apoptosis was inhibited after administration of the NLRP3 inhibitor MCC950, and TXNIP silencing could reduce the NLRP3 expression and apoptosis, while both effects of Ang II on TXNIP-NLRP3 and its apoptosis-inducing effect were inhibited by angiotensin II type I receptor (AT1R) blocker Telmisartan. Our results demonstrated that the TXNIP-NLRP3 inflammasome pathway mediated Ang II-induced INS-1 cell apoptosis and might hopefully become a novel target for the treatment of diabetes mellitus.

Coronary Artery Vasospasm Induced by 5-fluorouracil: Proposed Mechanisms, Existing Management Options and Future Directions

Cardiovascular disease and cancer are leading contributors to the global disease burden. As a result of cancer therapy-related cardiotoxicities, cardiovascular disease results in significant morbidity and mortality in cancer survivors and patients with active cancer. There is an unmet need for management of cardio-oncology conditions, which is predicted to reach epidemic proportions, and better understanding of their pathophysiology and treatment is urgently required. The proposed mechanisms underlying cardiotoxicity induced by 5-fluorouracil (5-FU) are vascular endothelial damage followed by thrombus formation, ischaemia secondary to coronary artery vasospasm, direct toxicity on myocardium and thrombogenicity. In patients with angina and electrocardiographic evidence of myocardial ischaemia due to chemotherapy-related coronary artery vasospasm, termination of chemotherapy and administration of calcium channel blockers or nitrates can improve ischaemic symptoms. However, coronary artery vasospasm can reoccur with 5-FU re-administration with limited effectiveness of vasodilator prophylaxis observed. While pre-existing coronary artery disease may increase the ischaemic potential of 5-FU, cardiovascular risk factors do not appear to completely predict the development of cardiac complications. Pharmacogenomic studies and genetic profiling may help predict the occurrence and streamline the treatment of 5-FU-induced coronary artery vasospasm. Echocardiographic measures such as the Tei index may help detect subclinical 5-FU cardiotoxicity. Further research is required to explore the cardioprotective effect of agents such as coenzyme complex, GLP-1 analogues and degradation inhibitors on 5-FU-induced coronary artery vasospasm.

Absence of TXNIP in Humans Leads to Lactic Acidosis and Low Serum Methionine Linked to Deficient Respiration on Pyruvate

Thioredoxin-interacting protein (TXNIP) is an α-arrestin that can bind to and inhibit the antioxidant protein thioredoxin (TXN). TXNIP expression is induced by glucose and promotes β-cell apoptosis in the pancreas, and deletion of its gene in mouse models protects against diabetes. TXNIP is currently studied as a potential new target for antidiabetic drug therapy. In this study, we describe a family with a mutation in the TXNIP gene leading to nondetectable expression of TXNIP protein. Symptoms of affected family members include lactic acidosis and low serum methionine levels. Using patient-derived TXNIP-deficient fibroblasts and myoblasts, we show that oxidative phosphorylation is impaired in these cells when given glucose and pyruvate but normalized with malate. Isolated mitochondria from these cells appear to have normal respiratory function. The cells also display a transcriptional pattern suggestive of a high basal activation of the Nrf2 transcription factor. We conclude that a complete lack of TXNIP in human is nonlethal and leads to specific metabolic distortions that are, at least in part, linked to a deficient respiration on pyruvate. The results give important insights into the impact of TXNIP in humans and thus help to further advance the development of antidiabetic drugs targeting this protein.

Increased thioredoxin-interacting protein in brain of mice exposed to chronic stress

Chronic stress is a key contributor to depression. Previous studies have shown that oxidative stress and inflammation are increased by chronic stress and in subjects with depression. Thioredoxin is a small redox protein that regulates cellular redox balance and signaling. This protein can reverse protein cysteine oxidative modifications such as sulfenylation and nitrosylation, and inhibit stress-regulated apoptosis signal-regulating kinase 1 pathway. Therefore thioredoxin plays an important role in cellular defense against oxidative stress. Thioredoxin-interacting protein is an endogenous thioredoxin inhibitor. In the present study, to understand the role of thioredoxin in chronic stress and depression, we have investigated thioredoxin, thioredoxin-interacting protein, sulfenylation, nitrosylation and apoptosis signal-regulating kinase 1 phosphorylation in brain of mice exposed to chronic unpredictable stress (CUS). We found that mice exposed to CUS displayed decreased exploratory, increased anhedonic and increased despair depressive-like behaviours. We also found that although CUS had no effect on thioredoxin protein levels, it significantly increased levels of thioredoxin-interacting protein in mouse hippocampus and frontal cortex. CUS also increased protein cysteine sulfenylation, protein cysteine nitrosylation and apoptosis signal-regulating kinase 1 phosphorylation in mouse hippocampus and frontal cortex. These findings suggest that chronic stress may upregulate thioredoxin-interacting protein, subsequently inhibiting thioredoxin activity and enhancing oxidative protein cysteine modification and apoptosis signal-regulating kinase 1 pathway. These results also indicate that thioredoxin-interacting protein may have potential for depression treatment.

Icariin Ameliorates Palmitate-Induced Insulin Resistance Through Reducing Thioredoxin-Interacting Protein (TXNIP) and Suppressing ER Stress in C2C12 Myotubes

Both thioredoxin-interacting protein (TXNIP) and endoplasmic reticulum (ER) stress are implicated in skeletal muscle insulin resistance. Icariin has been found to mimic insulin action in normal skeletal muscle C2C12 cells and display anti-diabetic properties in diet-induced obese mice. However, the underlying molecular mechanism remains to be well-established. Herein, we tested the hypothesis that the protective effects of icariin on free fatty acid-induced insulin resistance were attributed to its regulation on TXNIP protein levels and ER stress in skeletal muscle cells. We found that TXNIP mediated the saturated fatty acid palmitate (PA)-induced insulin resistance in C2C12 myotubes. Icariin treatment significantly restored PA-reduced proteasome activity resulting in reduction of TXNIP protein and suppression of ER stress, as well as improvement of insulin sensitivity. Proteasome inhibition by its specific inhibitor MG132 obviously abolished the inhibitory effect of icariin on PA-induced insulin resistance. In addition, MG132 supplementation markedly abrogated the impacts of icariin on ER stress and TXNIP-mediated downstream events such as inflammation and STAT3 phosphorylation. These results clearly indicate that icariin improves PA-induced skeletal muscle insulin resistance through a proteasome-dependent mechanism, by which icariin downregulats TXNIP levels and inhibits ER stress.

Glucocorticoid Upregulates Thioredoxin-interacting Protein in Cultured Neuronal Cells

Previous studies have shown that chronic stress and chronic stress hormone treatment induce oxidative damage in rodents. Thioredoxin (Trx) is a small redox protein that plays an important role in regulation of oxidative protein cysteine modification. A Trx reduced state is maintained by thioredoxin reductase (TrxR), and the thioredoxin-interacting protein (Txnip) is an endogenous inhibitor of Trx. The purpose of this study was to investigate the effects of chronic treatment with stress hormone corticosterone on Trx, TrxR and Txnip in cultured neuronal cells. Using immunoblotting analysis we found that although chronic corticosterone treatment had no effect on Trx and TrxR protein levels, this treatment significantly increased Txnip protein levels. Using immunocytochemistry we also found that chronic corticosterone treatment increased Txnip in both nucleus and cytosol, while glucocorticoid receptor inhibitor RU486 can block corticosterone-increased Txnip protein levels. Using biotin switch, dimedone conjugation and CRISPR/Cas9 methods we found that chronic corticosterone treatment increased protein nitrosylation and sulfenylation, while knocking out Txnip blocked corticosterone-induced protein nitrosylation and sulfenylation. Since Trx can reduce cysteine oxidative protein modification such as nitrosylation and sulfenylation, our findings suggest that chronic corticosterone treatment may upregulate Txnip by targeting glucocorticoid receptor, subsequently inhibiting Trx activity and enhancing oxidative protein cysteine modification, which contributes to corticosterone-caused oxidative damage.

The role of the thioredoxin/thioredoxin reductase system in the metabolic syndrome: towards a possible prognostic marker?

Mammalian thioredoxin reductase (TrxR) is a selenoprotein with three existing isoenzymes (TrxR1, TrxR2, and TrxR3), which is found primarily intracellularly but also in extracellular fluids. The main substrate thioredoxin (Trx) is similarly found (as Trx1 and Trx2) in various intracellular compartments, in blood plasma, and is the cell's major disulfide reductase. Thioredoxin reductase is necessary as a NADPH-dependent reducing agent in biochemical reactions involving Trx. Genetic and environmental factors like selenium status influence the activity of TrxR. Research shows that the Trx/TrxR system plays a significant role in the physiology of the adipose tissue, in carbohydrate metabolism, insulin production and sensitivity, blood pressure regulation, inflammation, chemotactic activity of macrophages, and atherogenesis. Based on recent research, it has been reported that the modulation of the Trx/TrxR system may be considered as a new target in the management of the metabolic syndrome, insulin resistance, and type 2 diabetes, as well as in the treatment of hypertension and atherosclerosis. In this review evidence about a possible role of this system as a marker of the metabolic syndrome is reported.

Nitrosative Stress as a Modulator of Inflammatory Change in a Model of Takotsubo Syndrome

Previous studies have shown that patients with Takotsubo syndrome (TS) have supranormal nitric oxide signaling, and post-mortem studies of TS heart samples revealed nitrosative stress. Therefore, we first showed in a female rat model that isoproterenol induces TS-like echocardiographic changes, evidence of nitrosative stress, and consequent activation of the energy-depleting enzyme poly(ADP-ribose) polymerase-1. We subsequently showed that pre-treatment with an inhibitor of poly(ADP-ribose) polymerase-1 ameliorated contractile abnormalities. These findings thus add to previous reports of aberrant β-adrenoceptor signaling (coupled with nitric oxide synthase activation) to elucidate mechanisms of impaired cardiac function in TS and point to potential methods of treatment.

TXNIP in Metabolic Regulation: Physiological Role and Therapeutic Outlook

Background & Objective:

Thioredoxin-interacting protein (TXNIP) also known as thioredoxin binding protein-2 is a ubiquitously expressed protein that interacts and negatively regulates expression and function of Thioredoxin (TXN). Over the last few years, TXNIP has attracted considerable attention due to its wide-ranging functions impacting several aspects of energy metabolism. TXNIP acts as an important regulator of glucose and lipid metabolism through pleiotropic actions including regulation of β-cell function, hepatic glucose production, peripheral glucose uptake, adipogenesis, and substrate utilization. Overexpression of TXNIP in animal models has been shown to induce apoptosis of pancreatic β-cells, reduce insulin sensitivity in peripheral tissues like skeletal muscle and adipose, and decrease energy expenditure. On the contrary, TXNIP deficient animals are protected from diet induced insulin resistance and type 2 diabetes.

Summary:

Consequently, targeting TXNIP is thought to offer novel therapeutic opportunity and TXNIP inhibitors have the potential to become a powerful therapeutic tool for the treatment of diabetes mellitus. Here we summarize the current state of our understanding of TXNIP biology, highlight its role in metabolic regulation and raise critical questions that could help future research to exploit TXNIP as a therapeutic target.

The A to Z of modulated cell patterning by mammalian thioredoxin reductases

Mammalian thioredoxin reductases (TrxRs) are selenocysteine-containing proteins (selenoproteins) that propel a large number of functions through reduction of several substrates including the active site disulfide of thioredoxins (Trxs). Well-known enzymatic systems that in turn are supported by Trxs and TrxRs include deoxyribonucleotide synthesis through ribonucleotide reductase, antioxidant defense through peroxiredoxins and methionine sulfoxide reductases, and redox modulation of a number of transcription factors. Although these functions may be essential for cells due to crucial roles in maintenance of cell viability and proliferation, findings during the last decade reveal that mammals have major redundancy in their cellular reductive systems. The synthesis of glutathione (GSH) and reductive functions of GSH-dependent pathways typically act in parallel with Trx-dependent pathways, with only one of these systems often being sufficient to support viability. Importantly, this does not imply that a modulation of the Trx system will remain without consequences, even when GSH-dependent pathways remain functional. As suggested by several recent findings, the Trx system in general and the TrxRs in particular, function as key regulators of signaling pathways. In this review article we will discuss findings that collectively suggest that modulation in mammalian systems of cytosolic TrxR1 (TXNRD1) or mitochondrial TrxR2 (TXNRD2) influence cell patterning and cellular stress responses. Effects of lower activities include increased adipogenesis, insulin responsiveness, glycogen accumulation, hyperproliferation, and distorted embryonic development, while increased activities correlate with decreased proliferation and extended lifespan, as well as worse cancer prognosis. The molecular mechanisms that underlie these diverse effects, involving regulation of protein phosphorylation cascades and of key transcription factors that guide cellular differentiation pathways, will be discussed. We conclude that the selenium-dependent oxidoreductases TrxR1 and TrxR2 should be considered as key components of signaling pathways that control cell differentiation and cellular stress responses.

DNA methylation and gene expression of TXNIP in adult offspring of women with diabetes in pregnancy

BACKGROUND

Fetal exposure to maternal diabetes increases the risk of type 2 diabetes (T2DM), possibly mediated by epigenetic mechanisms. Low blood TXNIP DNA methylation has been associated with elevated glucose levels and risk of T2DM, and increased skeletal muscle TXNIP gene expression was reported in subjects with impaired glucose metabolism or T2DM. Subcutaneous adipose tissue (SAT) and skeletal muscle play a key role in the control of whole body glucose metabolism and insulin action. The extent to which TXNIP DNA methylation levels are decreased and/or gene expression levels increased in SAT or skeletal muscle of a developmentally programmed at-risk population is unknown.

OBJECTIVE AND METHODS

The objective of this study was to investigate TXNIP DNA methylation and gene expression in SAT and skeletal muscle, and DNA methylation in blood, from adult offspring of women with gestational diabetes (O-GDM, n = 82) or type 1 diabetes (O-T1DM, n = 67) in pregnancy compared with offspring of women from the background population (O-BP, n = 57).

RESULTS

SAT TXNIP DNA methylation was increased (p = 0.032) and gene expression decreased (p = 0.001) in O-GDM, but these differences were attenuated after adjustment for confounders. Neither blood/muscle TXNIP DNA methylation nor muscle gene expression differed between groups.

CONCLUSION

We found no evidence of decreased TXNIP DNA methylation or increased gene expression in metabolic target tissues of offspring exposed to maternal diabetes. Further studies are needed to confirm and understand the paradoxical SAT TXNIP DNA methylation and gene expression changes in O-GDM subjects.

Epigenetic programming, early life nutrition and the risk of metabolic disease

Time separates the past from the present, during this period memory are formed - written in code and decoded to be read while other memories are erased - but when it comes to the epigenome some memories are harder to forget than others. Recent studies show chemical information is written in the context of the epigenome and codified on histone and non-histone proteins to regulate nuclear processes such as gene transcription. The genome is also subject to modification in the form of 5-methylcytosine, which has been implicated in metabolic memory. In this review, we examine some of the chemical modifications that signal early life events and explore epigenetic changes that underlie the diabetic vasculature. The fine balance between past and present is discussed, as it pertains to gestational diabetes and obesity in context to the Barker hypothesis. We also examine emerging experimental evidence suggesting the hypothalamus as a central regulator of obesity risk and explore current genomic medicine. As for how cells recall specific chemical information, we examine the experimental evidence implicating chemical cues on the epigenome, providing examples of diet during pregnancy and the increased risk of disease in offspring.

Estradiol Regulates Txnip and Prevents Intermittent Hypoxia-Induced Vascular Injury

Chronic intermittent hypoxia (IH) contributes to obstructive sleep apnea (OSA)-related cardiovascular diseases through increasing oxidative stress. It has been widely recognized that estradiol decreases the risk for cardiovascular disease, but the estrogen replacement therapy is limited for its side effects. Thioredoxin (Trx) and its endogenous inhibitor, thioredoxin-interacting protein (Txnip), are associated with the protective effect of estradiol in some conditions. In this study, we aimed to explore whether estradiol could protect against IH-induced vascular injury, and the possible effect of Trx-1/Txnip in this process. Forty-eight adult female C57/BL6J mice were randomly divided into 4 groups, ovariectomy combined with IH group, sham operation combined with IH group, IH group and the control group. The mice treated with IH for 8 hrs/day, and 28 days. IH induced the injury of aorta, and ovariectomized mice were more prone to the IH-induced aortic injury, with higher level of oxidative stress. In vitro, estradiol increased Trx-1 level, but decreased the level of Txnip and oxidative stress in human umbilical vein endothelial cells (HUVECs) treated with IH for 16 hrs. Knock-down of Txnip by specific siRNA rescued oxidative stress and apoptosis. In conclusion, estradiol protects against IH-induced vascular injury, partially through the regulation of Trx-1/Txnip pathway.

Endogenous hydrogen sulfide-mediated MAPK inhibition preserves endothelial function through TXNIP signaling

Mounting evidence demonstrated deficient cystathionine-γ-lyase (CSE)/H₂S implicated the development of cardiovascular disease. The present study aimed to evaluating the favorable action of CSE derived H₂S on endothelial function in CSE^-/- mice. CSE^-/- mice exhibited attenuated endothelium-dependent relaxations, coupled with reduction of endothelial nitric oxide synthase (eNOS) phosphorylation at site of Ser1177, increase of thioredoxin interacting protein (TXNIP) level and MAPK phosphorylation, which were corrected by sodium hydrosulfide chronic treatment for 8 weeks. Impaired relaxations to ACh and upregulated TXNIP of CSE^-/- mice aorta were partially corrected by p38 inhibitor, extracellular regulated protein kinase (ERK) inhibitor and c-Jun N-terminal kinase (JNK) inhibitor and totally corrected by combined treatment. Pharmacological inhibition of CSE with DL-propargylglycine (PPG) in vivo and ex vivo induced endothelial dysfunction. PPG stimulated the phosphorylation of p38, JNK and ERK in human umbilical vein endothelial cells (HUVECs). MAPK inhibition by combined treatment of p38, JNK and ERK inhibitors normalized the endothelial changes of eNOS phosphorylation and TXNIP protein level in CSE^-/- mice aorta and PPG-treated HUVECs. NaHS offered similar effect with MAKP inhibitors. TXNIP siRNA prevented against endothelial function by PPG and TXNIP overexpression mimics the detrimental effect of PPG treatment on endothelial function, whereas MAPK inhibitor or NaHS has no beneficial effect. In a word, Endogenous CSE/H₂S benefits against endothelial dysfunction through suppressing MAPK/TXNIP cascade. CSE deficiency and consequently lowered endogenous H₂S level should be considered as risk factors and biomarkers for endothelial dysfunction.

Interdisciplinary approach to compensation of hypoglycemia in diabetic patients with chronic heart failure

Diabetes mellitus is a chronic disease requiring lifelong control with hypoglycemic agents that must demonstrate excellent efficacy and safety profiles. In patients taking glucose-lowering drugs, hypoglycemia is a common cause of death associated with arrhythmias, increased thrombus formation, and specific effects of catecholamines due to sympathoadrenal activation. Focus is now shifting from merely glycemic control to multifactorial approach. In the context of individual drugs and classes, this article reviews interdisciplinary strategies evaluating metabolic effects of drugs for treatment of chronic heart failure (CHF) which can mask characteristic hypoglycemia symptoms. Hypoglycemia unawareness and cardiac autonomic neuropathy are discussed. Data suggesting that hypoglycemia modulates immune response are reviewed. The potential role of gut microbiota in improving health of patients with diabetes and CHF is emphasized. Reports stating that nondiabetic CHF patients can have life-threatening hypoglycemia associated with imbalance of thyroid hormones are discussed. Regular glycemic control based on HbA1c measurements and adequate pharmacotherapy remain the priorities in diabetes management. New antihyperglycemic drugs with safer profiles should be preferred in vulnerable CHF patients. Multidrug interactions must be considered. Emerging therapies with reduced hypoglycemia risk, telemedicine, sensor technologies, and genetic testing predicting hypoglycemia risk may help solving the challenges of hypoglycemia in CHF patients with diabetes. Interdisciplinary work may involve cardiologists, diabetologists/endocrinologists, immunologists, gastroenterologists, microbiologists, nutritionists, imaging specialists, geneticists, telemedicine experts, and other relevant specialists. This review emphasizes that systematic knowledge on pathophysiology of hypoglycemia in diabetic patients with CHF is largely lacking and the gaps in our understanding require further discoveries.

Cardiac metabolism - A promising therapeutic target for heart failure

Both heart failure with reduced ejection fraction (HFrEF) and with preserved ejection fraction (HFpEF) are associated with high morbidity and mortality. Although many established pharmacological interventions exist for HFrEF, hospitalization and death rates remain high, and for those with HFpEF (approximately half of all heart failure patients), there are no effective therapies. Recently, the role of impaired cardiac energetic status in heart failure has gained increasing recognition with the identification of reduced capacity for both fatty acid and carbohydrate oxidation, impaired function of the electron transport chain, reduced capacity to transfer ATP to the cytosol, and inefficient utilization of the energy produced. These nodes in the genesis of cardiac energetic impairment provide potential therapeutic targets, and there is promising data from recent experimental and early-phase clinical studies evaluating modulators such as carnitine palmitoyltransferase 1 inhibitors, partial fatty acid oxidation inhibitors and mitochondrial-targeted antioxidants. Metabolic modulation may provide significant symptomatic and prognostic benefit for patients suffering from heart failure above and beyond guideline-directed therapy, but further clinical trials are needed.

The RPMI-1640 vitamin mixture promotes bovine blastocyst development in vitro and downregulates gene expression of TXNIP with epigenetic modification of associated histones

Diverse environmental conditions surrounding preimplantation embryos, including available nutrients, affect their metabolism and development in both short- and long-term manner. Thioredoxin-interacting protein (TXNIP) is a possible marker for preimplantation stress that is implicated in in vitro fertilization- (IVF) induced long-term DOHaD effects. B vitamins, as participants in one-carbon metabolism, may affect preimplantation embryos by epigenetic alterations of metabolically and developmentally important genes. In vitro-produced bovine embryos were cultured with or without Roswell Park Memorial Institute 1640 vitamin mixture, containing B vitamins and B vitamin-like substances, from day 3 after IVF and we evaluated blastocyst development and TXNIP messenger RNA (mRNA) expression in the blastocysts by reverse transcription-quantitative polymerase chain reaction. The degree of trimethylation of histone H3 lysine 27 (H3K27me3) at TXNIP promoter was examined semi-quantitatively by chromatin immunoprecipitation polymerase chain reaction. Total H3K27me3 were also compared between the groups by Western blot analysis. The vitamin treatment significantly increased the rates of blastocyst development (P<0.05) and their hatching (P<0.001) from the zona pellucida by day 8. The mRNA expression of TXNIP was lower (P<0.01) in blastocysts in the vitamin-mixture-treated group concomitant with higher (P<0.05) level of H3K27me3 of its promoter compared with the control group. The total H3K27me3 in the vitamin-mixture-treated group was also higher (P<0.01) than that in the control group. The epigenetic control of genes related to important metabolic processes during the periconceptional period by nutritional conditions in utero and/or in vitro may have possible implication for the developmental programming during this period that may impact the welfare and production traits of farm animals.