Thioredoxin-interacting protein: A new therapeutic target in bone metabolism disorders?

Inhibition of the Foxo3/Txnip Axis Alleviates Ventilator-Induced Diaphragmatic Dysfunction by Downregulating MuRF1

Ventilator-induced diaphragm dysfunction (VIDD) is one of the main causes of weaning from mechanical ventilation (MV). The forkhead box O3 (Foxo3) has been identified as being involved in regulating the contractile function of skeletal muscle. This study aimed to figure out the regulatory role and mechanism of Foxo3 on VIDD. The mouse myoblast C2C12 cells were stimulated using different intensities of stress to mimic the in-vitro VIDD model. 3- (4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and TdT-mediated dUTP nick end labeling (TUNEL) assays were applied to check cell viability and apoptosis, respectively. Cellular inflammation and oxidative stress levels were evaluated by measuring cellular inflammatory factors (IL-1β and TNF-α) and oxidative stress markers (SOD and MDA). The release of oxygen species (ROS) was assayed by cellular immunofluorescence. The expression of apoptosis-associated proteins (Bax and Bcl-2), Gpx4, Slc7a11, Ptgs2, Foxo3, Txnip, Murf1, Atrogin-1, Nlrp3, Asc, and Caspase1 was gauged using Western blot. The rats with or without MV therapy were treated with the Foxo3 inhibitor Carbenoxolone (CBX) to characterize the impact of Foxo3 on VIDD. Stress stimulation dampened myogenic cell viability, boosted apoptosis, inflammation, oxidative stress, and ROS release, and activated the expression of Foxo3 and Txnip pathways. Overexpression of Txnip or Murf1 lessened the protective effect of FOxO3 inhibition on myoblasts. Downregulation of Txnip or Murf1 mitigated myoblasts dysfunction that was induced by Foxo3 overexpression. In vivo, inhibition of Foxo3 mitigated MV-induced diaphragmatic atrophy and reduced contractility, inflammation, and oxidative stress in rats. Inhibition of Foxo3 eased VIDD by downregulating Txnip and Murf1.

Therapeutic prospects and potential mechanisms of Prdx6: as a novel target in musculoskeletal disorders

With the global population aging, musculoskeletal disorders (MSDs) have posed significant physical and psychological health challenges for patients as well as a substantial economic burden on society. The advancements in conservative and surgical interventions for MSDs have been remarkable in recent years; however, the current treatment modalities still fall short of meeting the optimal requirements of patients. Recently, peroxiredoxin 6 (Prdx6) has gained considerable attention from researchers due to its remarkable antioxidative, anti-inflammatory, and anti-apoptotic properties. It has been found that Prdx6 is involved in multiple system diseases, including MSDs; however, the exact role of Prdx6 in MSDs is still lacking. This study aimed to summarize the structure, regulatory mechanism, and potential function of Prdx6. These findings may demonstrate Prdx6 as a novel target for inhibiting the advancement of MSDs.

Direct inhibition of the TXNIP-NLRP3-GSDMD pathway reduces pyroptosis in colonocytes and alleviates ulcerative colitis in mice by the small compound PEITC

Ulcerative colitis (UC) is a chronic inflammatory bowel disease. The etiology of UC is multifaceted, and the underlying pathogenesis remains incompletely understood. Pyroptosis, programmed cell death mediated by the gasdermins, is a pivotal driver of UC pathology due to its dual role in epithelial barrier disruption and inflammatory amplification. We previously showed that phenethyl isothiocyanate (PEITC), an isothiocyanate derived from cruciferous vegetables, alleviated acute liver injury in mice by suppressing hepatocyte pyroptosis. In this study we evaluated the therapeutic potential of PEITC in the treatment of UC and the underlying mechanisms. UC mouse models were established by administration of 2.5% (w/v) dextran sulfate sodium (DSS) daily for 7 days. PEITC (5, 10, or 20 mg·kg-1·d-1, i.g.) was given 2 days before the start of modeling, and the dosing lasted for a total of 10 days. We showed that during the progression of DSS-induced UC, the pyroptosis pathway was activated accompanied by elevated expression levels of thioredoxin-interacting protein (TXNIP) and NOD-like receptor thermal protein domain associated protein 3 (NLRP3), as well as the activation of caspase-1, gasdermin D (GSDMD) and interleukin-1β (IL-1β). Treatment with PEITC dose-dependently reduced TXNIP and NLRP3 expression while inhibiting the cleavage of proteins associated with the pyroptosis pathway such as caspase-1, GSDMD, and IL-1β. We confirmed the inhibitory effect of PEITC on colonocyte pyroptosis in an in vitro model established in HT29 cells, where PEITC (0.2, 1, 5 µM) dose-dependently inhibited TXNIP and NLRP3 expression and the activation of pro-caspase-1, GSDMD and pro-IL-1β. We revealed that PEITC is directly bound to TXNIP and disrupted the interaction between TXNIP and NLRP3, leading to diminished cellular inflammation and oxidative stress levels. In conclusion, this study demonstrates that PEITC disrupts the interaction of TXNIP and NLRP3 by binding to TXNIP, inhibits NLRP3 activation and colonocyte pyroptosis, and thus effectively alleviates UC symptoms in mice. This study offers novel drug targets along with potential therapeutic candidates for the clinical prevention and treatment of UC.

Peripheral nerves modulate the peri-implant osteogenesis under type 2 diabetes through exosomes derived from schwann cells via miR-15b-5p/Txnip signaling axis

Studies have shown that the prognosis of dental implant treatment in patients with diabetes is not as good as that in the non-diabetes population. The nerve plays a crucial role in bone metabolism, but the role and the mechanism of peripheral nerves in regulating peri-implant osteogenesis under Type 2 diabetes mellitus (T2DM) situation remains unclear. In this study, it was shown that high glucose-stimulated Schwann cells (SCs) inhibited peri-implant osteogenesis via their exosomes. SCs-derived exosomes were analyzed for their miRNA cargo, identifying miR-15b-5p as significantly downregulated in high glucose conditions. T2DM rats and patients exhibited decreased miR-15b-5p expression, correlating with impaired bone microarchitecture. Luciferase assays and Western blotting confirmed TXNIP as a direct miR-15b-5p target, implicating its involvement in ROS signaling and inflammation-related osteogenesis suppression. Furthermore, normal SCs exosomes improved bone parameters around dental implants in T2DM rats. These findings underscore the therapeutic potential of miR-15b-5p and normal SCs exosomes in mitigating poor peri-implant bone regeneration of T2DM patients, offering insights into the molecular mechanisms of peripheral nerves governing bone regeneration in diabetic conditions.

E3 ubiquitination ligase XIAP lightens diabetes-induced cognitive impairment by inactivating TXNIP-ERS-mediated neuronal injury

Diabetes-induced cognitive dysfunction (DCD) is a neurological disorder associated with diabetes, characterized by cognitive impairment driven by neuronal injury from chronic high glucose (HG) exposure. This study aims to elucidate the role and mechanisms of the X-linked inhibitor of apoptosis protein (XIAP)/thioredoxin-interacting protein (TXNIP) in hippocampal neuron cell death and cognitive function within DCD models. A diabetic rat model was established using a high-fat/sucrose diet and streptozotocin injection. Primary hippocampal neurons were stimulated with HG to mimic diabetic conditions. Cognitive and memory functions were assessed using the Morris water maze (MWM) and novel object recognition test (ORT).

Thioredoxin Interacting Protein Expressed in Osteoblasts Mediates the Anti-Proliferative Effects of High Glucose and Modulates the Expression of Osteocalcin

BACKGROUND

Hyperglycemia is associated with impaired bone health in patients with diabetes mellitus. Although a direct detrimental effect of hyperglycemia on the bone has been previously reported, the specific molecular mediator(s) responsible for the inhibitory effect of high glucose levels on the bone remains unclear. We hypothesized that thioredoxin-interacting protein (Txnip), an essential mediator of oxidative stress, is such a mediator.

METHODS

We cultured MG-63 cells (immortalized human osteoblasts) with normal or high glucose concentrations and transfected them with scrambled or Txnip-specific small interfering RNA (siRNA).

RESULTS

High glucose levels increased Txnip expression and reduced MG-63 cell proliferation. The high-glucose level mediated reduction in cell proliferation was prevented in Txnip siRNA-transfected cells. In addition, we demonstrated that silencing Txnip mRNA expression in osteoblasts reduced the expression of the osteocalcin gene. Our results suggest that high glucose levels or silencing of Txnip mRNA expression may induce apoptosis in osteoblasts.

CONCLUSIONS

Our findings indicate that Txnip is an intracellular mediator of the anti-proliferative effects of extracellular high glucose levels on osteoblasts.

TXNIP mediated by EZH2 regulated osteogenic differentiation in hBmscs and MC3T3-E1 cells through the modulation of oxidative stress and PI3K/AKT/Nrf2 pathway

BACKGROUND

Previous research has identified a significant role of Thioredoxin-interacting protein (TXNIP) in bone loss. The purpose of this investigation was to assess the role and the underlying molecular mechanisms of TXNIP in the osteogenic differentiation of human bone marrow stromal cells (hBMSCs) and pre-osteoblast MC3T3-E1 cells.

METHODS

Human bone marrow stem cells (hBMSCs) and MC3T3-E1 cells were used to induce osteogenic differentiation. The expression of genes and proteins was assessed using RT-qPCR and western blot, respectively. ChIP assay was used to validate the interaction between genes. The osteogenic differentiation ability of cells was reflected using ALP staining and detection of ALP activity. The mineralization ability of cells was assessed using ARS staining. DCFCA staining was employed to evaluate the intracellular ROS level.

RESULTS

Initially, downregulation of TXNIP and upregulation of EZH2 were observed during osteogenesis in hBMSCs and MC3T3-E1 cells. Additionally, it was discovered that EZH2 negatively regulates TXNIP expression in these cells. Furthermore, experiments indicated that the knockdown of TXNIP stimulated the activation of the PI3K/AKT/Nrf2 signaling pathway in hBMSCs and MC3T3- E1 cells, thus inhibiting the production of reactive oxygen species (ROS). Further functional experiments revealed that overexpression of TXNIP inhibited the osteogenic differentiation in hBMSCs and MC3T3-E1 cells by enhancing ROS produc-tion. On the other hand, knockdown of TXNIP promoted the osteogenic differentiation capacity of hBMSCs and MC3T3-E1 cells through the activation of the PI3K/AKT/Nrf2 pathway.

CONCLUSION

In conclusion, this study demonstrated that TXNIP expression, under the regulation of EZH2, plays a crucial role in the osteogenic differentiation of hBMSCs and MC3T3-E1 cells by regulating ROS production and the PI3K/AKT/Nrf2 pathway.

Selenium as a Modulator of Redox Reactions in the Prevention and Treatment of Cardiovascular Diseases

Cardiovascular diseases stand as the predominant global cause of mortality, exerting a profound impact on both life expectancy and its quality. Given their immense public health burden, extensive efforts have been dedicated to comprehending the underlying mechanisms and developing strategies for prevention and treatment. Selenium, a crucial participant in redox reactions, emerges as a notable factor in maintaining myocardial cell homeostasis and influencing the progression of cardiovascular disorders. Some disorders, such as Keshan disease, are directly linked with its environmental deficiency. Nevertheless, the precise extent of its impact on the cardiovascular system remains unclear, marked by contradictory findings in the existing literature. High selenium levels have been associated with an increased risk of developing hypertension, while lower concentrations have been linked to heart failure and atrial fibrillation. Although some trials have shown its potential effectiveness in specific groups of patients, large cohort supplementation attempts have generally yielded unsatisfactory outcomes. Consequently, there persists a significant need for further research aimed at delineating specific patient cohorts and groups of diseases that would benefit from selenium supplementation.

Rutin attenuates ensartinib-induced hepatotoxicity by non-transcriptional regulation of TXNIP

Ensartinib, an approved ALK inhibitor, is used as a first-line therapy for advanced ALK-positive non-small cell lung cancer in China. However, the hepatotoxicity of ensartinib seriously limits its clinical application and the regulatory mechanism is still elusive. Here, through transcriptome analysis we found that transcriptional activation of TXNIP was the main cause of ensartinib-induced liver dysfunction. A high TXNIP level and abnormal TXNIP translocation severely impaired hepatic function via mitochondrial dysfunction and hepatocyte apoptosis, and TXNIP deficiency attenuated hepatocyte apoptosis under ensartinib treatment. The increase in TXNIP induced by ensartinib is related to AKT inhibition and is mediated by MondoA. Through screening potential TXNIP inhibitors, we found that the natural polyphenolic flavonoid rutin, unlike most reported TXNIP inhibitors can inhibit TXNIP by binding to TXNIP and partially promoting its proteasomal degradation. Further studies showed rutin can attenuate the hepatotoxicity of ensartinib without antagonizing its antitumor effects. Accordingly, we suggest that TXNIP is the key cause of ensartinib-induced hepatotoxicity and rutin is a potential clinically safe and feasible therapeutic strategy for TXNIP intervention.

Short- and long-term exposure to high glucose induces unique transcriptional changes in osteoblasts in vitro

Bone is increasingly recognized as a target for diabetic complications. In order to evaluate the direct effects of high glucose on bone, we investigated the global transcriptional changes induced by hyperglycemia in osteoblasts in vitro. Rat bone marrow-derived mesenchymal stromal cells were differentiated into osteoblasts for 10 days, and prior to analysis, they were exposed to hyperglycemia (25 mM) for the short-term (1 or 3 days) or long-term (10 days). Genes and pathways regulated by hyperglycemia were identified using mRNA sequencing and verified with qPCR. Genes upregulated by 1-day hyperglycemia were, for example, related to extracellular matrix organization, collagen synthesis and bone formation. This stimulatory effect was attenuated by 3 days. Long-term exposure impaired osteoblast viability, and downregulated, for example, extracellular matrix organization and lysosomal pathways, and increased intracellular oxidative stress. Interestingly, transcriptional changes by different exposure times were mostly unique and only 89 common genes responding to glucose were identified. In conclusion, short-term hyperglycemia had a stimulatory effect on osteoblasts and bone formation, whereas long-term hyperglycemia had a negative effect on intracellular redox balance, osteoblast viability and function.

SALVIANOLIC ACID A ATTENUATES ANGIOTENSIN II-INDUCED CARDIAC FIBROSIS THROUGH REGULATING THE TXNIP SIGNALING PATHWAY

ABSTRACT

Cardiac fibrosis, characterized by excessive collagen accumulation in heart tissues, poses a significant clinical challenge in various heart diseases and complications. Although salvianolic acid A (Sal A) from Danshen ( Salvia miltiorrhiza ) has shown promise in the treatment of ischemic heart disease, myocardial infarction, and atherosclerosis, its effects on cardiac fibrosis remain unexplored. Our study investigated the efficacy of Sal A in reducing cardiac fibrosis and elucidated its underlying molecular mechanisms. We observed that Sal A demonstrated significant cardioprotective effects against Angiotensin II (Ang II)-induced cardiac remodeling and fibrosis, showing a dose-dependent reduction in fibrosis in mice and suppression of cardiac fibroblast proliferation and fibrotic protein expression in vitro . RNA sequencing revealed that Sal A counteracted Ang II-induced upregulation of Txnip, and subsequent experiments indicated that it acts through the inflammasome and ROS pathways. These findings establish the antifibrotic effects of Sal A, notably attenuated by Txnip overexpression, and highlight its significant role in modulating inflammation and oxidative stress pathways. This underscores the importance of further research on Sal A and similar compounds, especially regarding their effects on inflammation and oxidative stress, which are key factors in various cardiovascular diseases.

Single-cell characterisation of tissue homing CD4 + and CD8 + T cell clones in immune-mediated refractory arthritis

BACKGROUND

Immune-mediated arthritis is a group of autoinflammatory diseases, where the patient's own immune system attacks and destroys synovial joints. Sustained remission is not always achieved with available immunosuppressive treatments, warranting more detailed studies of T cell responses that perpetuate synovial inflammation in treatment-refractory patients.

METHODS

In this study, we investigated CD4 + and CD8 + T lymphocytes from the synovial tissue and peripheral blood of patients with treatment-resistant immune-mediated arthritis using paired single-cell RNA and TCR-sequencing. To gain insights into the trafficking of clonal families, we compared the phenotypes of clones with the exact same TCRß amino acid sequence between the two tissues.

RESULTS

Our results show that both CD4 + and CD8 + T cells display a more activated and inflamed phenotype in the synovial tissue compared to peripheral blood both at the population level and within individual T cell families. Furthermore, we found that both cell subtypes exhibited clonal expansion in the synovial tissue.

CONCLUSIONS

Our findings suggest that the local environment in the synovium drives the proliferation of activated cytotoxic T cells, and both CD4 + and CD8 + T cells may contribute to tissue destruction and disease pathogenesis.

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.

The Notch1 signaling pathway directly modulates the human RANKL-induced osteoclastogenesis

Notch signaling is an evolutionary conserved pathway with a key role in tissue homeostasis, differentiation and proliferation. It was reported that Notch1 receptor negatively regulates mouse osteoclast development and formation by inhibiting the expression of macrophage colony-stimulating factor in mesenchymal cells. Nonetheless, the involvement of Notch1 pathway in the generation of human osteoclasts is still controversial. Here, we report that the constitutive activation of Notch1 signaling induced a differentiation block in human mononuclear CD14+ cells directly isolated from peripheral blood mononuclear cells (PBMCs) upon in vitro stimulation to osteoclasts. Additionally, using a combined approach of single-cell RNA sequencing (scRNA-Seq) simultaneously with a panel of 31 oligo-conjugated antibodies against cell surface markers (AbSeq assay) as well as unsupervised learning methods, we detected four different cell stages of human RANKL-induced osteoclastogenesis after 5 days in which Notch1 signaling enforces the cell expansion of specific subsets. These cell populations were characterized by distinct gene expression and immunophenotypic profiles and active Notch1, JAK/STAT and WNT signaling pathways. Furthermore, cell-cell communication analyses revealed extrinsic modulators of osteoclast progenitors including the IL7/IL7R and WNT5a/RYK axes. Interestingly, we also report that Interleukin-7 receptor (IL7R) was a downstream effector of Notch1 pathway and that Notch1 and IL7R interplay promoted cell expansion of human RANKL-induced osteoclast progenitors. Taken together, these findings underline a novel cell pattern of human osteoclastogenesis, outlining the key role of Notch1 and IL-7R signaling pathways.

VDUP1 Deficiency Promotes the Severity of DSS-Induced Colitis in Mice by Inducing Macrophage Infiltration

The loss of vitamin D3 upregulated protein 1 (VDUP1) has been implicated in the pathogenesis of various inflammation-related diseases. Notably, reduced expression of VDUP1 has been observed in clinical specimens of ulcerative colitis (UC). However, the role of VDUP1 deficiency in colitis remains unclear. In this study, we investigated the role of VDUP1 in dextran sulfate sodium (DSS)-induced experimental colitis in mice. VDUP1-deficient mice were more susceptible to DSS-induced colitis than their wild-type (WT) littermates after 2% DSS administration. VDUP1-deficient mice exhibited an increased disease activity index (DAI) and histological scores, as well as significant colonic goblet cell loss and an increase in apoptotic cells. These changes were accompanied by a significant decrease in MUC2 mRNA expression and a marked increase in proinflammatory cytokines and chemokines within damaged tissues. Furthermore, phosphorylated NF-κB p65 expression was significantly upregulated in damaged tissues in the context of VDUP1 deficiency. VDUP1 deficiency also led to significant infiltration of macrophages into the site of ulceration. An in vitro chemotaxis assay confirmed that VDUP1 deficiency enhanced bone marrow-derived macrophage (BMDM) chemotaxis induced by CCL2. Overall, this study highlights VDUP1 as a regulator of UC pathogenesis and a potential target for the future development of therapeutic strategies.

TXNIP: A key protein in the cellular stress response pathway and a potential therapeutic target

Thioredoxin-interacting protein (TXNIP), which is also known as thioredoxin-binding protein 2 (TBP2), directly interacts with the major antioxidant protein thioredoxin (TRX) and inhibits its antioxidant function and expression. However, recent studies have demonstrated that TXNIP is a multifunctional protein with functions beyond increasing intracellular oxidative stress. TXNIP activates endoplasmic reticulum (ER) stress-mediated nucleotide-binding oligomerization domain (NOD)-like receptor protein-3 (NLRP3) inflammasome complex formation, triggers mitochondrial stress-induced apoptosis, and stimulates inflammatory cell death (pyroptosis). These newly discovered functions of TXNIP highlight its role in disease development, especially in response to several cellular stress factors. In this review, we provide an overview of the multiple functions of TXNIP in pathological conditions and summarize its involvement in various diseases, such as diabetes, chronic kidney disease, and neurodegenerative diseases. We also discuss the potential of TXNIP as a therapeutic target and TXNIP inhibitors as novel therapeutic drugs for treating these diseases.

Oxidative-Stress-Related Genes in Osteoporosis: A Systematic Review

Osteoporosis is characterized by a decline in bone mineral density (BMD) and increased fracture risk. Free radicals and antioxidant systems play a central role in bone remodeling. This study was conducted to illustrate the role of oxidative-stress-related genes in BMD and osteoporosis. A systematic review was performed following the PRISMA guidelines. The search was computed in PubMed, Web of Sciences, Scopus, EBSCO, and BVS from inception to November 1st, 2022. The risk of bias was evaluated using the Joanna Briggs Institute Critical Appraisal Checklist tool. A total of 427 potentially eligible articles exploring this search question were detected. After removing duplicates (n = 112) and excluding irrelevant manuscripts based on screenings of their titles and abstracts (n = 317), 19 articles were selected for full-text review. Finally, 14 original articles were included in this systematic review after we applied the exclusion and inclusion criteria. Data analyzed in this systematic review indicated that oxidative-stress-related genetic polymorphisms are associated with BMD at different skeletal sites in diverse populations, influencing the risk of osteoporosis or osteoporotic fracture. However, it is necessary to look deep into their association with bone metabolism to determine if the findings can be translated into the clinical management of osteoporosis and its progression.