Thioredoxin Domain-containing Research Articles

Insights into the functional properties of thioredoxin domain-containing protein 12 (TXNDC12): Antioxidant activity, immunological expression, and wound-healing effect in yellowtail clownfish (Amphiprion clarkii)

Thioredoxin domain-containing protein 12 (TXNDC12) is a member of the thioredoxin-like superfamily that contributes to various thiol-dependent metabolic activities in all living organisms. In this research, the TXNDC12 gene from yellowtail clownfish (Amphiprion clarkii) was structurally characterized using in silico tools, assessed for immunological expression, and evaluated for biological activity using recombinant protein and cellular overexpression. The deduced coding sequence of AcTXNDC12 comprised a 522-bp nucleotide, encoding 173 amino acids with a predicted molecular mass of 19.198 kDa. The AcTXNDC12 protein consists of a66WCGAC70 active motif and a170GDEL173 signature. The highest tissue-specific expression of AcTXNDC12 was observed in the brain tissue, with significant modulation observed in the blood and gill tissues following stimulation of polyinosinic: polycytidylic acid, lipopolysaccharides (LPS), and Vibrio harveyi. In functional assays, recombinant AcTXNDC12 protein (rAcTXNDC12) showed insulin disulfide reduction activity, 2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid) decolorization antioxidant capacity, and ferric (Fe3+) reducing antioxidant potential. Additionally, a significant reduction in nitric oxide production was observed in AcTXNDC12-overexpressed RAW 264.7 cells upon LPS stimulation. Furthermore, genes associated with the regulation of oxidative stress, including nuclear factor erythroid 2-related factor 2 (Nrf2), catalase (Cat), peroxiredoxin 1 (Prx1), and ribonucleotide reductase catalytic subunit M1 (Rrm1) were significantly upregulated in fathead minnow cells overexpressing AcTXNDC12 in response to H2O2 treatment. The scratch wound healing assay demonstrated tissue regeneration and cell proliferation ability upon AcTXNDC12 overexpression. Altogether, the current study elucidated the antioxidant activity, immunological importance, and wound-healing effect of the AcTXNDC12 gene in yellowtail clownfish, providing valuable insights for advancing the aquaculture of A. clarkii fish.

Parecoxib Enhances Resveratrol against Human Colorectal Cancer Cells through Akt and TXNDC5 Inhibition and MAPK Regulation.

In this study, we discovered the mechanisms underlying parecoxib and resveratrol combination's anti-cancer characteristics against human colorectal cancer DLD-1 cells. We studied its anti-proliferation and apoptosis-provoking effect by utilizing cell viability 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, fluorescence microscope, gene overexpression, Western blot, and flow cytometry analyses. Parecoxib enhanced the ability of resveratrol to inhibit cell viability and increase apoptosis. Parecoxib in combination with resveratrol strongly enhanced apoptosis by inhibiting the expression of thioredoxin domain containing 5 (TXNDC5) and Akt phosphorylation. Parecoxib enhanced resveratrol-provoked c-Jun N-terminal kinase (JNK) and p38 phosphorylation. Overexpression of TXNDC5 and repression of JNK and p38 pathways significantly reversed the inhibition of cell viability and stimulation of apoptosis by the parecoxib/resveratrol combination. This study presents evidence that parecoxib enhances the anti-cancer power of resveratrol in DLD-1 colorectal cancer cells via the inhibition of TXNDC5 and Akt signaling and enhancement of JNK/p38 MAPK pathways. Parecoxib may be provided as an efficient drug to sensitize colorectal cancer by resveratrol.

Proteome-wide Ligand and Target Discovery by Using Strain-Enabled Cyclopropane Electrophiles.

The evolving use of covalent ligands as chemical probes and therapeutic agents could greatly benefit from an expanded array of cysteine-reactive electrophiles for efficient and versatile proteome profiling. Herein, to expand the current repertoire of cysteine-reactive electrophiles, we developed a new class of strain-enabled electrophiles based on cyclopropanes. Proteome profiling has unveiled that C163 of lactate dehydrogenase A (LDHA) and C88 of adhesion regulating molecule 1 (ADRM1) are ligandable residues to modulate the protein functions. Moreover, fragment-based ligand discovery (FBLD) has revealed that one fragment (Y-35) shows strong reactivity toward C66 of thioredoxin domain-containing protein 12 (TXD12), and its covalent binding has been demonstrated to impact its downstream signal pathways. TXD12 plays a pivotal role in enabling Y-35 to exhibit its antisurvival and antiproliferative effects. Finally, dicarbonitrile-cyclopropane has been demonstrated to be an electrophilic warhead in the development of GSTO1-involved dual covalent inhibitors, which is promising to alleviate drug resistance.

TXNDC5 Plays a Crucial Role in Regulating Endoplasmic Reticulum Activity through Different ER Stress Signaling Pathways in Hepatic Cells.

The pathogenesis of non-alcoholic fatty liver disease (NAFLD) is influenced by a number of variables, including endoplasmic reticulum stress (ER). Thioredoxin domain-containing 5 (TXNDC5) is a member of the protein disulfide isomerase family and acts as an endoplasmic reticulum (ER) chaperone. Nevertheless, the function of TXNDC5 in hepatocytes under ER stress remains largely uncharacterized. In order to identify the role of TXNDC5 in hepatic wild-type (WT) and TXNDC5-deficient (KO) AML12 cell lines, tunicamycin, palmitic acid, and thapsigargin were employed as stressors. Cell viability, mRNA, protein levels, and mRNA splicing were then assayed. The protein expression results of prominent ER stress markers indicated that the ERN1 and EIF2AK3 proteins were downregulated, while the HSPA5 protein was upregulated. Furthermore, the ATF6 protein demonstrated no significant alterations in the absence of TXNDC5 at the protein level. The knockout of TXNDC5 has been demonstrated to increase cellular ROS production and its activity is required to maintain normal mitochondrial function during tunicamycin-induced ER stress. Tunicamycin has been observed to disrupt the protein levels of HSPA5, ERN1, and EIF2AK3 in TXNDC5-deficient cells. However, palmitic acid has been observed to disrupt the protein levels of ATF6, HSPA5, and EIF2AK3. In conclusion, TXNDC5 can selectively activate distinct ER stress pathways via HSPA5, contingent on the origin of ER stress. Conversely, the absence of TXNDC5 can disrupt the EIF2AK3 cascade.

Sodium-glucose cotransporter 2 inhibitors attenuate vascular calcification by suppressing endoplasmic reticulum protein thioredoxin domain containing 5 dependent osteogenic reprogramming

AimsVascular calcification is strongly linked to the development of major adverse cardiovascular events, but effective treatments are lacking. Sodium-glucose cotransporter 2 (SGLT2) inhibitors are an emerging category of oral hypoglycemic drugs that have displayed marked effects on metabolic and cardiovascular diseases, including recently reported vascular medial calcification. However, the roles and underlying mechanisms of SGLT2 inhibitors in vascular calcification have not been fully elucidated. Thus, we aimed to further determine whether SGLT2 inhibitors protect against vascular calcification and to investigate the mechanisms involved. Methods and resultsA computed tomography angiography investigation of coronary arteries from 1554 patients with type 2 diabetes revealed that SGLT2 inhibitor use was correlated with a lower Agatston calcification score. In the vitamin D3 overdose, 5/6 nephrectomy chronic kidney disease-induced medial calcification and Western diet-induced atherosclerotic intimal calcification models, dapagliflozin (DAPA) substantially alleviated vascular calcification in the aorta. Furthermore, we showed that DAPA reduced vascular calcification via Runx2-dependent osteogenic transdifferentiation in vascular smooth muscle cells (VSMCs). Transcriptome profiling revealed that thioredoxin domain containing 5 (TXNDC5) was involved in the attenuation of vascular calcification by DAPA. Rescue experiments showed that DAPA-induced TXNDC5 downregulation in VSMCs blocked the protective effect on vascular calcification. Furthermore, TXNDC5 downregulation disrupted protein folding-dependent Runx2 stability and promoted subsequent proteasomal degradation. Moreover, DAPA downregulated TXNDC5 expression via amelioration of oxidative stress and ATF6-dependent endoplasmic reticulum stress. Consistently, the class effects of SGLT2 inhibitors on vascular calcification were validated with empagliflozin in intimal and medial calcification models. ConclusionsSGLT2 inhibitors ameliorate vascular calcification through blocking endoplasmic reticulum stress-dependent TXNDC5 upregulation and promoting subsequent Runx2 proteasomal degradation, suggesting that SGLT2 inhibitors are potentially beneficial for vascular calcification treatment and prevention.

Modeling alcohol-associated liver disease in humans using adipose stromal or stem cell-derived organoids

Alcohol-associated liver disease (ALD) is a prevalent liver disease, yet research is hampered by the lack of suitable and reliable human ALD models. Herein, we generated human adipose stromal/stem cell (hASC)-derived hepatocellular organoids (hAHOs) and hASC-derived liver organoids (hALOs) in a three-dimensional system using hASC-derived hepatocyte-like cells and endodermal progenitor cells, respectively. The hAHOs were composed of major hepatocytes and cholangiocytes. The hALOs contained hepatocytes and nonparenchymal cells and possessed a more mature liver function than hAHOs. Upon ethanol treatment, both steatosis and inflammation were present in hAHOs and hALOs. The incubation of hALOs with ethanol resulted in increases in the levels of oxidative stress, the endoplasmic reticulum protein thioredoxin domain-containing protein 5 (TXNDC5), the alcohol-metabolizing enzymes ADH1B and ALDH1B1, and extracellular matrix accumulation, similar to those of liver tissues from patients with ALD. These results present a useful approach for understanding the pathogenesis of ALD in humans, thus facilitating the discovery of effective treatments.

Thioredoxin Domain Containing 5 (TXNDC5): Friend or Foe?

This review focuses on the thioredoxin domain containing 5 (TXNDC5), also known as endoplasmic reticulum protein 46 (ERp46), a member of the protein disulfide isomerase (PDI) family with a dual role in multiple diseases. TXNDC5 is highly expressed in endothelial cells, fibroblasts, pancreatic β-cells, liver cells, and hypoxic tissues, such as cancer endothelial cells and atherosclerotic plaques. TXNDC5 plays a crucial role in regulating cell proliferation, apoptosis, migration, and antioxidative stress. Its potential significance in cancer warrants further investigation, given the altered and highly adaptable metabolism of tumor cells. It has been reported that both high and low levels of TXNDC5 expression are associated with multiple diseases, such as arthritis, cancer, diabetes, brain diseases, and infections, as well as worse prognoses. TXNDC5 has been attributed to both oncogenic and tumor-suppressive features. It has been concluded that in cancer, TXNDC5 acts as a foe and responds to metabolic and cellular stress signals to promote the survival of tumor cells against apoptosis. Conversely, in normal cells, TXNDC5 acts as a friend to safeguard cells against oxidative and endoplasmic reticulum stress. Therefore, TXNDC5 could serve as a viable biomarker or even a potential pharmacological target.

Hepatitis E virus ORF3 protein hijacking thioredoxin domain-containing protein 5 (TXNDC5) for its stability to promote viral particle release.

Hepatitis E virus (HEV) infection is the leading cause of acute viral hepatitis worldwide. After the synthesis and modification in the cells, the mature ORF3 protein is essential for HEV release. However, the host protein involved in this process has yet to be determined. Here, we reported a novel host protein, thioredoxin domain-containing protein 5 (TXNDC5), as a chaperone, contributing to HEV release by facilitating ORF3 protein stability in the endoplasmic reticulum through interacting with non-palmitoylated ORF3 protein. However, we also found that in the knockout-TXNDC5 stable cell lines, the HEV ORF3 protein may hijack other proteins for its stabilization. For the first time, our study demonstrated the involvement of TXNDC5 in viral particle release. These findings provide some new insights into the process of the HEV life cycle, the interaction between HEV and host factors, and a new direction for antiviral design.

Endoplasmic Reticulum Protein TXNDC5 Interacts with PRDX6 and HSPA9 to Regulate Glutathione Metabolism and Lipid Peroxidation in the Hepatic AML12 Cell Line.

Non-alcoholic fatty liver disease or steatosis is an accumulation of fat in the liver. Increased amounts of non-esterified fatty acids, calcium deficiency, or insulin resistance may disturb endoplasmic reticulum (ER) homeostasis, which leads to the abnormal accumulation of misfolded proteins, activating the unfolded protein response. The ER is the primary location site for chaperones like thioredoxin domain-containing 5 (TXNDC5). Glutathione participates in cellular oxidative stress, and its interaction with TXNDC5 in the ER may decrease the disulfide bonds of this protein. In addition, glutathione is utilized by glutathione peroxidases to inactivate oxidized lipids. To characterize proteins interacting with TXNDC5, immunoprecipitation and liquid chromatography-mass spectrometry were used. Lipid peroxidation, reduced glutathione, inducible phospholipase A2 (iPLA2) and hepatic transcriptome were assessed in the AML12 and TXNDC5-deficient AML12 cell lines. The results showed that HSPA9 and PRDX6 interact with TXNDC5 in AML12 cells. In addition, TXNDC5 deficiency reduced the protein levels of PRDX6 and HSPA9 in AML12. Moreover, lipid peroxidation, glutathione and iPLA2 activities were significantly decreased in TXNDC5-deficient cells, and to find the cause of the PRDX6 protein reduction, proteasome suppression revealed no considerable effect on it. Finally, hepatic transcripts connected to PRDX6 and HSPA9 indicated an increase in the Dnaja3, Mfn2 and Prdx5 and a decrease in Npm1, Oplah, Gstp3, Gstm6, Gstt1, Serpina1a, Serpina1b, Serpina3m, Hsp90aa1 and Rps14 mRNA levels in AML12 KO cells. In conclusion, the lipid peroxidation system and glutathione mechanism in AML12 cells may be disrupted by the absence of TXNDC5, a novel protein-protein interacting partner of PRDX6 and HSPA9.

Thioredoxin domain containing 5 is involved in the hepatic storage of squalene into lipid droplets in a sex-specific way

Hepatic thioredoxin domain-containing 5 (TXNDC5) is a member of the protein disulfide isomerase family found associated with anti-steatotic properties of squalene and located in the endoplasmic reticulum and in lipid droplets. Considering that the latter are involved in hepatic squalene accumulation, the present research was aimed to investigate the role of TXNDC5 on hepatic squalene management in mice and in the AML12 hepatic cell line. Wild-type and TXNDC5-deficient (KO) mice were fed Western diets with or without 1% squalene supplementation for 6 weeks. In males, but not in females, absence of TXNDC5 blocked hepatic, but not duodenal, squalene accumulation. Hepatic lipid droplets were isolated and characterized using label-free LC-MS/MS analysis. TXNDC5 accumulated in this subcellular compartment of mice receiving squalene and was absent in TXNDC5-KO male mice. The latter mice were unable to store squalene in lipid droplets. CALR and APMAP were some of the proteins that responded to the squalene administration in all studied conditions. CALR and APMAP were positively associated with lipid droplets in the presence of squalene and they were decreased by the absence of TXNDC5. The increased squalene content was reproduced in vitro using AML12 cells incubated with squalene-loaded nanoparticles and this effect was not observed in an engineered cell line lacking TXNDC5. The phenomenon was also present when incubated in the presence of a squalene epoxidase inhibitor, suggesting a mechanism of squalene exocytosis involving CALR and APMAP. In conclusion, squalene accumulation in hepatic lipid droplets is sex-dependent on TXNDC5 that blocks its secretion.

Piperlongumine is a ligand for the orphan nuclear receptor 4A1 (NR4A1).

Piperlongumine and derivatives are being developed as anticancer agents which act primarily as inducers of reactive oxygen species (ROS) in cancer cell lines. Many of the anticancer activities of piperlongumine resemble those observed for bis-indole derived compounds that bind the orphan nuclear receptor 4A1 (NR4A1) and act as inverse receptor agonists to inhibit NR4A1-regulated pro-oncogenic pathways and genes. In this study we show that like other NR4A1 inverse agonists piperlongumine inhibited RKO, SW480 and HCT116 colon cancer cell growth migration and invasion and induced apoptosis. Piperlongumine also downregulated the pro-reductant isocitrate dehydrogenase 1 (IDH1) and thioredoxin domain-containing 5 (TXNDC5) gene products resulting in the induction of ROS as previously observed for other inverse NR4A1 agonists. ROS also induced sestrin2 and this resulted in activation of AMPK phosphorylation and inhibition of mTOR pathway signaling. It has previously been reported that these pathways/genes are also regulated by inverse NR4A1 agonists or by knockdown of NR4A1. We also observed that piperlongumine directly bound NR4A1, inhibited NR4A1-dependent transactivation and interactions of the NR4A1/Sp1 complex bound to the GC-rich promoter of the NR4A1-regulated G9a gene.

Early plasma proteomic biomarkers and prediction model of acute respiratory distress syndrome after cardiopulmonary bypass: a prospective nested cohort study.

Early recognition of the risk of acute respiratory distress syndrome (ARDS) after cardiopulmonary bypass (CPB) may improve clinical outcomes. The main objective of this study was to identify proteomic biomarkers and develop an early prediction model for CPB-ARDS. We conducted three prospective nested cohort studies of all consecutive patients undergoing cardiac surgery with CPB at XXX Hospital. Plasma proteomic profiling was performed in ARDS patients and matched controls (Cohort 1, April, 2021 to July, 2021) at multiple timepoints: before CPB (T1), at end of CPB (T2), and 24 h after CPB (T3). Then, for Cohort 2 (August, 2021 to July, 2022), biomarker expression was measured and verified in the plasma. Furthermore, lung ischemia/reperfusion injury (LIRI) models and sham-operation were established in 50 rats to explore the tissue-level expression of biomarkers identified in the aforementioned clinical cohort. Subsequently, a machine learning-based prediction model incorporating protein and clinical predictors from Cohort 2 for CPB-ARDS was developed and internally validated. Model performance was externally validated on Cohort 3 (January, 2023 to March, 2023). A total of 709 proteins were identified, with 9, 29, and 35 altered proteins between ARDS cases and controls at T1, T2, and T3, respectively, in Cohort 1. Following quantitative verification of several predictive proteins in Cohort 2, higher levels of thioredoxin domain containing 5 (TXNDC5), cathepsin L (CTSL), and NPC intracellular cholesterol transporter 2 (NPC2) at T2 were observed in CPB-ARDS patients. A dynamic online predictive nomogram was developed based on three proteins (TXNDC5, CTSL, and NPC2) and two clinical risk factors (CPB time, massive blood transfusion), with excellent performance (precision: 83.33%, sensitivity: 93.33%, specificity: 61.16%, F1 score: 85.05%). Mean area under the receiver operating characteristics curve (AUC) of the model after 10-fold cross-validation was 0.839 (95% confidence interval (CI): 0.824 to 0.855). Model discrimination and calibration were maintained during external validation dataset testing, with AUC of 0.820 (95% CI: 0.685 to 0.955) and Brier Score of 0.177 (95% CI: 0.147 to 0.206). Moreover, the considerably overexpressed TXNDC5 and CTSL proteins identified in the plasma of patients with CPB-ARDS, exhibited a significant upregulation in the lung tissue of LIRI rats. This study identified several novel predictive biomarkers, developed and validated a practical prediction tool using biomarker and clinical factor combinations for individual prediction of CPB-ARDS risk. Assessing the plasma TXNDC5, CTSL, and NPC2 levels might identify patients who warrant closer follow-up and intensified therapy for ARDS prevention following major surgery.

High Thioredoxin Domain-Containing Protein 11 Expression Is Associated with Tumour Progression in Glioma.

Glioblastoma (GBM) is the most common primary brain malignancy in adults. Despite multimodal treatment that involves maximal safe resection, concurrent chemoradiotherapy, and tumour treatment for supratentorial lesions, the prognosis remains poor. The current median overall survival is only <2 years, and the 5-year survival is only 7.2%. Thioredoxin domain-containing protein 11 (TXNDC11), also known as EF-hand binding protein 1, was reported as an endoplasmic reticulum stress-induced protein. The present study aimed to elucidate the prognostic role of TXNDC11 in GBM. We evaluated the clinical parameters and TXNDC11 scores in gliomas from hospitals. Additionally, proliferation, invasion, migration assays, apoptosis, and temozolomide (TMZ)-sensitivity assays of GBM cells were conducted to evaluate the effects of short interfering RNA (siRNA) on these processes. In addition, these cells were subjected to Western blotting to detect the expression levels of N-cadherin, E-cadherin, and Cyclin D1. High levels of TXNDC11 protein expression were significantly associated with World Health Organization (WHO) high-grade tumour classification and poor prognosis. Multivariate analysis revealed that in addition to the WHO grade, TXNDC11 protein expression was also an independent prognostic factor of glioma. In addition, TXNDC11 silencing inhibited proliferation, migration, and invasion and led to apoptosis of GBM cells. However, over-expression of TXNDC11 enhanced proliferation, migration, and invasion. Further, TXNDC11 knockdown downregulated N-cadherin and cyclin D1 expression and upregulated E-cadherin expression in GBM cells. Knock-in TXNDC11 return these. Finally, in vivo, orthotopic xenotransplantation of TXNDC11-silenced GBM cells into nude rats promoted slower tumour growth and prolonged survival time. TXNDC11 is a potential oncogene in GBMs and may be an emerging therapeutic target.

The Value of Thioredoxin Level and its Gene Polymorphism in the Diagnosis of Post- HCV Hepatocellular Carcinoma

Background: Hepatocellular carcinoma (HCC) is one of the most common malignancies and a leading cause of cancer-related death worldwide. Indeed, we need a novel tumor marker other than AFP for early detection and to improve the outcome. Serum thioredoxin is a promising protein involved in the pathogenesis of many malignancies. The study aims to evaluate serum thioredoxin and its gene polymorphism in HCC in cirrhotic patients due to HCV infection. Patients and Methods: 350 patients with HCC, 350 patients with chronic liver diseases, and 300 healthy controls were enrolled in our study. Serum thioredoxin level was measured by ELISA, and molecular study of thioredoxin domain-containing 5 (TXNDC5) gene polymorphism (rs1225943) polymorphism using real-time polymerase chain reaction by Taqman allele discrimination was done for all subjects. Results: Our study revealed a significant increase in serum thioredoxin levels in patients with HCC compared to chronic liver diseases and healthy controls. Using the Receiver operating characteristic (ROC) curve at the area under the curve (AUC) 0.917 and a cut-off value of &gt; 14.6 U/ml, our overall sensitivity and specificity for the HCC group over the other groups were 86 % and 92.15%, respectively with 92.2% positive predictive value and 54.9% negative predictive value. The molecular study of TXNDC5 gene polymorphism (rs1225943) polymorphism revealed no significant difference between the studied groups. Conclusion: Serum thioredoxin may be used as a promising tumor marker for HCC. Future research is needed to assess its use as a single or combined with other markers in the diagnosis and follow-up of the patients after interventions.

Thioredoxin domain-containing protein 9 protects cells against UV-B-provoked apoptosis via NF-κB/p65 activation in cutaneous squamous cell carcinoma.

Cutaneous squamous cell carcinoma (cSCC), a type of non-melanoma skin cancer (NMSC), is the most common malignancy worldwide. Thioredoxin (TXN) domain-containing protein 9 (TXNDC9) is a member of the TXN family that is important in cell differentiation. However, the biological function of this protein in cancer, particularly cSCC, is still unknown. In the present study, our experiments revealed the protective effects of TXNDC9 on UV-B-irritated cSCC cells. The initial findings showed that TXNDC9 is significantly upregulated in cSCC tissue and cells compared to normal skin tissue and keratinocytes. UV-B radiation robustly induces the expression of TXNDC9, and UV-B-induced cSCC cell death is boosted by TXNDC9 deficiency. Moreover, cSCC cells lacking TXNDC9 displayed attenuated activation of the NF-κB pathway. Additional studies by inhibiting TXNDC9 confirmed this finding, as TXNDC9 deficiency attenuated UV-B radiation-induced translocation of NF-κB p65 from the cytoplasm to the nucleus of cSCC. In conclusion, our work demonstrates the biological roles of TXNDC9 in cSCC progression and may provide a novel therapeutic target to treat cSCC in the future.

Expression analysis and functional characterization of thioredoxin domain-containing protein 11.

The endoplasmic reticulum (ER) is a crucial organelle that regulates both the folding, modification and transport of many proteins and senses certain stimuli inside and outside of cells. ER-associated degradation (ERAD), including SEL1L is a crucial mechanism to maintain homeostasis. In this study, we performed comparative proteome analysis in wild-type (wt) and SEL1L-deficient cells. We found constitutively high expression of thioredoxin domain-containing protein 11 (TXNDC11) mRNA and protein in our SEL1L-deficient HEK293 cells by RT-PCR and Western blot analysis. The TXNDC11 gene possesses a well-conserved unfolded protein response element (UPRE) around its transcription start site, and ER stress increased TXNDC11 mRNA and luciferase reporter activity via this putative UPRE in HEK293 cells. The amounts of TXNDC11 protein in wild-type and SEL1L-deficient cells with or without thapsigargin (Tg) treatment were parallel to their mRNAs in these cells, which was almost proportional to spliced XBP1 (sXBP1) mRNA expression. The establishment and characterization of TXNDC11-deficient HEK293 cells revealed that the expression of three different ER resident stress sensors, ATF6α, CREB3 and CREB3L2, is regulated by TXNDC11. The rate of disappearance of the three proteins by CHX treatment in wt cells was remarkably different, and the full-length CREB3L2 protein was almost completely degraded within 15min after CHX treatment. TXNDC11 deficiency increased the expression of each full-length form under resting conditions and delayed their disappearance by CHX treatment. Interestingly, the degree of increase in full-length CREB3/CREB3L2 by TXNDC11 deficiency was apparently higher than that in full-length ATF6α. The increase in these proteins by TXNDC11 deficiency was hardly correlated with the expression of each mRNA. Treatment with ER stress inducers influenced each full-length mature form, and the difference in each full-length form observed in wt and TXNDC11-deficient cells was smaller. This study demonstrated that TXNDC11 is an ER stress-inducible gene regulated by the IRE1-sXBP1 pathway. In addition, TXNDC11 is involved in the regulation of ATF6α, CREB3 and CREB3L2 protein expression, although the contribution to the stability of these proteins is quite variable. Therefore, its further characterization will provide new insights for understanding protein homeostasis in ER physiology and pathology.

Abstract 139: Precision Nanomedicine Targeting Novel Endothelial Mechano-sensing Mechanisms To Treat Vascular Diseases

Endothelial mechano-transduction mechanisms are instrumental to vascular health and disease but targeting disease-causing mechano-sensing pathways remains extremely challenging. Atherosclerosis preferentially develops at arterial curvatures and bifurcations where disturbed blood flow activates endothelium, leading to peripheral artery disease, carotid artery disease and ischemic stroke. Nevertheless; current atherosclerosis therapies mainly target systematic risk factors but not the vasculature per se . This underscores the significance and unique opportunity to identify and target novel mechanosensitive mechanisms in activated endothelium subjected to disturbed flow. Our objectives are to (1) delineate novel endothelial mechano-sensing mechanisms and (2) devise innovative precision nanomedicine approaches targeting these disease-causing mechano-sensitive pathways. Using multiple new transgenic mouse lines, our studies demonstrated that disturbed flow (DF) significantly increases the endothelial expression of TXNDC5 (thioredoxin domain containing 5) and microRNA-92a (miR-92a), two atherogenic molecules driving atherogenesis. Mechanistically, DF-induced TXNDC5 increases proteasome-mediated degradation of heat shock factor 1 and consequently promotes eNOS/NOS3 protein degradation. Meanwhile, DF induces endothelial miR-92a to suppress key anti-inflammatory molecules such as KLF2, KLF4, and PLPP3. We successfully formulated nanoparticles to deliver TXNDC5-targeting CRISPR/Cas9 plasmids driven by an endothelium-specific promoter (CDH5), which effectively deleted endothelial TXNDC5 expression and reduced atherosclerosis in Apoe -/- mice. Moreover, VCAM1-tageting polyelectrolyte complex micelles were engineered to selectively deliver miR-92a inhibitors to inflamed endothelium, which markedly decreased arterial stenosis and atherosclerosis in Apoe -/- mice. These results elucidate novel endothelial mechano-sensing mechanisms and provide a proof of concept of innovative targeted nanomedicine approaches, addressing an unmet medical need in vascular therapies.

Inhibition of TXNDC5 attenuates lipopolysaccharide-induced septic shock by altering inflammatory responses

AbstractSepsis and its severe form, septic shock, represent the leading cause of death among hospitalized patients. Thioredoxin is a ubiquitous protein essential for cellular redox balance and its aberrant expression is associated with a wide spectrum of inflammation-related pathological conditions. The current study aimed to compare the expression of thioredoxin domain containing 5 (TXNDC5) in septic patients with or without septic shock and to explore the potential regulatory effects of TXNDC5 in sepsis. We analyzed the RNA expression data downloaded from the Gene Expression Omnibus database and measured the plasma level of TXNDC5 in septic patients. The results showed that TXNDC5 was upregulated in patients with septic shock compared to septic patients without shock or healthy controls. We further treated wild-type mice and cultured macrophages with lipopolysaccharide (LPS) and found that TXNDC5 was highly expressed in mice with LPS-induced sepsis and macrophages subjected to LPS stimulation compared to corresponding controls. Then a mouse strain with targeted depletion of Txndc5 was generated. Txndc5 depletion reduced inflammatory cytokine production and affected the recruitment of macrophages and neutrophils into the blood and peritoneum of mice challenged with LPS. Further analysis revealed that TXNDC5 inhibition alleviated LPS-induced sepsis by inhibiting the NF-κB signaling pathway. In summary, these findings suggested that the inhibition of TXNDC5 may be a potential approach to treat sepsis and related syndromes.Thioredoxin domain containing 5 (TXNDC5) is highly expressed in patients with septic shock. It is also upregulated in mice with lipopolysaccharide (LPS)-induced sepsis and mouse macrophages subjected to LPS stimulation. Txndc5 depletion reduced inflammatory cytokine production and affected recruitment of macrophages and neutrophils in LPS-challenged mice. TXNDC5 inhibition alleviated LPS-induced sepsis by inhibiting the nuclear factor kappa B signaling pathway. These findings suggest that TXNDC5 inhibition may be a therapeutic approach for sepsis.

Thioredoxin Domain Containing 5 Suppression Elicits Serum Amyloid A-Containing High-Density Lipoproteins.

Thioredoxin domain containing 5 (TXNDC5) is a protein disulfide isomerase involved in several diseases related to oxidative stress, energy metabolism and cellular inflammation. In a previous manuscript, a negative association between fatty liver development and hepatic Txndc5 expression was observed. To study the role of TXNDC5 in the liver, we generated Txndc5-deficient mice. The absence of the protein caused an increased metabolic need to gain weight along with a bigger and fatter liver. RNAseq was performed to elucidate the putative mechanisms, showing a substantial liver overexpression of serum amyloid genes (Saa1, Saa2) with no changes in hepatic protein, but discrete plasma augmentation by the gene inactivation. Higher levels of malonyldialdehyde, apolipoprotein A1 and platelet activating factor-aryl esterase activity were also found in serum from Txndc5-deficient mice. However, no difference in the distribution of high-density lipoproteins (HDL)-mayor components and SAA was found between groups, and even the reactive oxygen species decreased in HDL coming from Txndc5-deficient mice. These results confirm the relation of this gene with hepatic steatosis and with a fasting metabolic derive remedying an acute phase response. Likewise, they pose a new role in modulating the nature of HDL particles, and SAA-containing HDL particles are not particularly oxidized.

Targeting mechanosensitive endothelial TXNDC5 to stabilize eNOS and reduce atherosclerosis in vivo.

Although atherosclerosis preferentially develops at arterial curvatures and bifurcations where disturbed flow (DF) activates endothelium, therapies targeting flow-dependent mechanosensing pathways in the vasculature are unavailable. Here, we provided experimental evidence demonstrating a previously unidentified causal role of DF-induced endothelial TXNDC5 (thioredoxin domain containing 5) in atherosclerosis. TXNDC5 was increased in human and mouse atherosclerotic lesions and induced in endothelium subjected to DF. Endothelium-specific Txndc5 deletion markedly reduced atherosclerosis in ApoE−/− mice. Mechanistically, DF-induced TXNDC5 increases proteasome-mediated degradation of heat shock factor 1, leading to reduced heat shock protein 90 and accelerated eNOS (endothelial nitric oxide synthase) protein degradation. Moreover, nanoparticles formulated to deliver Txndc5-targeting CRISPR-Cas9 plasmids driven by an endothelium-specific promoter (CDH5) significantly increase eNOS protein and reduce atherosclerosis in ApoE−/− mice. These results delineate a new molecular paradigm that DF-induced endothelial TXNDC5 promotes atherosclerosis and establish a proof of concept of targeting endothelial mechanosensitive pathways in vivo against atherosclerosis.