SIRT1-dependent deacetylation of Txnip H3K9ac is critical for exenatide-improved diabetic kidney disease

Glucagon-like peptide 1 receptor agonist exenatide (exendin-4) has potential protective capabilities against diabetic kidney disease (DKD). However, the underlying mechanism has not been fully elucidated. The expression of thioredoxin-interacting protein (Txnip) is upregulated during DKD progression by histone acetylation. Sirtuin 1 (SIRT1) is a deacetylase and is decreased in DKD, which indicates that it may regulate Txnip in this disease. Here, we used whole-body heterozygous Sirt1 knockout (Sirt1+/-) and kidney-specific Sirt1 knockout (KSK) mice to investigate whether SIRT1 regulates Txnip via histone deacetylation in DKD and exenatide-alleviated DKD. Exenatide substantially improved renal pathological damage, decreased the albumin-to-creatinine ratio (ACR), upregulated SIRT1 expression, and downregulated Txnip expression in kidneys of high-fat diet-treated C57BL/6J mice. However, these effects diminished in Sirt1+/- and KSK mice under exenatide treatment. The downregulation of Txnip expression by exendin-4 in high-glucose-treated SV40 MES13 cells was hampered during Sirt1 knockdown. These results demonstrate that kidney SIRT1 is indispensable in exenatide-improved DKD and downregulation of Txnip expression. Exendin-4 mechanistically downregulated Txnip histone 3 lysine 9 acetylation (H3K9ac) in a SIRT1-dependent manner and decreased spliced X-box binding protein 1 (XBP1s) recruitment to the Txnip promoter. These findings provide epigenetic evidence elucidating the specific mechanism for exenatide-mediated DKD alleviation and highlight the importance of Txnip as a promising therapeutic target for DKD.

Mechanisms of pulmonary microvascular endothelial cells barrier dysfunction induced by LPS: The roles of ceramides and the Txnip/NLRP3 inflammasome

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) are characterized by pulmonary microvascular endothelial cells (PMVECs) barrier dysfunction and proinflammatory cytokine influx into lung tissue, resulting in pulmonary oedema. Ceramide overproduction is an important mediator of pulmonary hyperinflammation and pulmonary oedema in Acute lung injury (ALI). Ceramides induce NLRP3 inflammasome activation are essential for the hyperinflammatory response. However, the roles and specific mechanisms of ceramide-induced NLRP3 inflammasome activation, proinflammatory cytokine manufacturing and PMVECs barrier dysfunction in ALI are unclear. Herein, pretreatment with the acid sphingomyelinase (ASMase) inhibitor imipramine (but not a neutral sphingomyelinase (NSMase) inhibitor or de novo pathway inhibitor) significantly inhibited ceramide early production in rats with lipopolysaccharide (LPS)-induced ALI; Furthermore, the Txnip/NLRP3 inflammasome activation, proinflammatory cytokine release, increased PMVECs permeability and lung injury were significantly decreased. Verapamil, a Txnip inhibitor, substantially inhibited Txnip/NLRP3 inflammasome activation, proinflammatory cytokine release, increased PMVECs permeability and lung injury in rats with C8-ceramide-induced ALI. In vitro, short hairpin RNA-mediated Txnip silencing significantly inhibited C8-ceramide-induced Txnip/NLRP3 inflammasome activation in NR8383 alveolar macrophages (AMs) and early secretion of the proinflammatory cytokines IL-1β (4-12 h) as well as IL-6 and TNF-α at subsequent times (later than 12 h). However, C8-ceramide significantly increased the early secretion (within 8 h) of the proinflammatory cytokines IL-1β, IL-6 and TNF-α in a co-culture model of NR8383 AMs and PMVECs, and Txnip silencing of NR8383 AMs inhibited the secretion of pro-inflammatory cytokines and reduced cytoskeletal rearrangements, intercellular connection breakage and hyperpermeability in PMVECs. Overall, our results suggest that in LPS-induced ALI, ceramide-mediated Txnip/NLRP3 inflammasome activation in NR8383 AMs leads to early IL-1β release, subsequently inducing PMVECs injury and release of the proinflammatory cytokines IL-6 and TNF-α, ultimately leading to PMVECs barrier dysfunction and ALI.

Txnip deficiency promotes β-cell proliferation in the HFD-induced obesity mouse model

Elucidating the mechanisms of regulation of β-cell proliferation is key to understanding the pathogenesis of diabetes mellitus. Txnip is a tumor suppressor that is upregulated in diabetes and plays an important role in the regulation of insulin sensitivity; however, its potential effect on pancreatic β-cell proliferation remains unclear. Here, we evaluated the role of Txnip in pancreatic β-cell compensatory proliferation by subjecting WT and Txnip knockout (KO) mice to a high-fat diet (HFD). Our results demonstrate that Txnip deficiency improves glucose tolerance and increases insulin sensitivity in HFD-induced obesity. The antidiabetogenic effect of Txnip deficiency was accompanied by increased β-cell proliferation and enhanced β-cell mass expansion. Furthermore, Txnip deficiency modulated the expression of a set of transcription factors with key roles in β-cell proliferation and cell cycle regulation. Txnip KO in HFD mice also led to activated levels of p-PI3K, p-AKT, p-mTOR and p-GSK3β, suggesting that Txnip may act via PI3K/AKT signaling to suppress β-cell proliferation. Thus, our work provides a theoretical basis for Txnip as a new therapeutic target for the treatment of diabetes mellitus.

Identification of Gm15441, a Txnip antisense lncRNA, as a critical regulator in liver metabolic homeostasis

Background

The majority of mammalian genome is composed of non-coding regions, where numerous long non-coding RNAs (lncRNAs) are transcribed. Although lncRNAs have been identified to regulate fundamental biological processes, most of their functions remain unknown, especially in metabolic homeostasis. Analysis of our recent genome-wide screen reveals that Gm15441, a thioredoxin-interacting protein (Txnip) antisense lncRNA, is the most robustly induced lncRNA in the fasting mouse liver. Antisense lncRNAs are known to regulate their sense gene expression. Given that Txnip is a critical metabolic regulator of the liver, we aimed to investigate the role of Gm15441 in the regulation of Txnip and liver metabolism.

Methods

We examined the response of Gm15441 and Txnip under in vivo metabolic signals such as fasting and refeeding, and in vitro signals such as insulin and key metabolic transcription factors. We investigated the regulation of Txnip expression by Gm15441 and the underlying mechanism in mouse hepatocytes. Using adenovirus-mediated liver-specific overexpression, we determined whether Gm15441 regulates Txnip in the mouse liver and modulates key aspects of liver metabolism.

Results

We found that the expression levels of Gm15441 and Txnip showed a similar response pattern to metabolic signals in vivo and in vitro, but that their functions were predicted to be opposite. Furthermore, we found that Gm15441 robustly reduced Txnip protein expression in vitro through sequence-specific regulation and translational inhibition. Lastly, we confirmed the Txnip inhibition by Gm15441 in vivo (mice) and found that Gm15441 liver-specific overexpression lowered plasma triglyceride and blood glucose levels and elevated plasma ketone body levels.

Conclusions

Our data demonstrate that Gm15441 is a potent Txnip inhibitor and a critical metabolic regulator in the liver. This study reveals the therapeutic potential of Gm15441 in treating metabolic diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-021-00722-1.

Ceramide induces the apoptosis of non‑small cell lung cancer cells through the Txnip/Trx1 complex

Ceramide is a biologically active sphingomyelin that inhibits cell growth and proliferation. In previous studies, it was demonstrated that the use of lipopolysaccharides induces acid sphingomyelinases to produce ceramide, promoting lung cancer cell apoptosis; however, the specific mechanisms of this action remain unclear. Thioredoxin‑interacting protein (Txnip) plays an important role in the signal transmission of redox reactions inside and outside the cell. Thus, it was hypothesized that ceramide induces apoptosis in lung adenocarcinoma cells (A549 and PC9) by modulating the Txnip/Trx1 complex. In the present study, the Cell Counting kit‑8 method was used to detect cell activity and the drug concentration. Hoechst 33258 staining and flow cytometry were used to detect cell apoptosis, and the positional association between Txnip and Trx1 upregulated by ceramide was observed by immunofluorescence confocal microscopy. Reverse transcription‑quantitative polymerase chain reaction and western blot analysis were used to detect the changes in related gene, mRNA and protein expression levels. The results revealed that ceramide treatment resulted in the upregulation of Txnip and in the reduction of Trx1 activities. However, the Txnip inhibitor, verapamil, reversed these changes. The analysis of mRNA expression further verified the changes observed in the protein expression of Txnip, Trx1 and apoptosis‑related proteins. On the whole, the present study demonstrates that ceramide induces the apoptosis of lung cancer cells by regulating the Txnip/Trx1 complex.

Impact of Acidosis-Regulated MicroRNAs on the Expression of Their Target Genes in Experimental Tumors In Vivo

In comparison to normal tissue, solid tumors show an acidic extracellular pH, which results from hypoxia-induced glycolytic metabolism and the Warburg effect. Since acidosis modulates the expression of different microRNAs (e.g., miR-7, miR-183, miR-203, miR-215), microRNAs and their targets might be mediators between tumor acidosis and malignant behavior. The aim of this study was to investigate how modulation of these microRNAs affects the expression of their targets (Crem, cAMP-responsive element modulator; Gls2, glutaminase 2; Txnip, thioredoxin-interacting protein) in experimental tumors in vivo and whether these changes are acidosis dependent. The study was performed in two experimental tumor lines of the rat (AT-1 prostate carcinoma, Walker-256 mammary carcinoma). The results showed that all three targets were regulated by acidosis in vivo, Crem and Gls2 being downregulated and Txnip upregulated in both models. In AT-1 tumors at normal tumor pH, miR-203 overexpression increased Txnip expression by about 75%, whereas in Walker-256 tumors, miR-7 reduced protein expression. In more acidic tumors, no impact of microRNAs on Txnip expression was seen. On the other hand, Gls2 was significantly increased in acidic tumors by miR-183 or miR-7 overexpression (cell line dependent). As this increase was not present under control conditions, an acidosis-dependent effect can be assumed. These results indicate that tumor acidosis modulates the expression of targets of pH-sensitive microRNAs in experimental tumors. Especially the protein expression of Gls2 might be regulated via changes of microRNAs, which then affects the malignant progression of tumors.

Validation of an air/liquid interface device for TiO2 nanoparticle toxicity assessment on NR8383 cells: preliminary results

nvestigations on adverse biological effects of nanoparticles (NP) are performed usually either in vivo on rodents or in vitro under submerged conditions where NP are in suspension into cell culture media. However, sedimentation of NP in vitro is a continuous process and to assess the exact deposited cellular dose remains difficult, as the cellular internal dose is a function of time. Moreover, the cellular responses to NP under submerged culture conditions or by exposing rodents by nose-only to NP aerosols might differ from those observed at physiological settings at the air-liquid interface (ALI). Rat alveolar NR8383 macrophages were exposed to aerosols at the air-liquid interface. We studied TiO2 NM105, a mixture of anatase and rutile. NR8383 cells were exposed to a single dose of 3.0 cm2/cm2 of TiO2 aerosol. Following RNA extraction, transcriptome allowing full coverage of the rat genome was performed, and differentially expressed genes were retrieved. Their products were analyzed for functions and interaction with String DB. Only 126 genes were differentially expressed and 98 were recognized by String DB and give us the gene expression signature of exposed rat alveolar NR8383 macrophages. Among them, 13 display relationships at a high confidence level and the ten most differentially expressed compared to unexposed cells were: Chac1, Ccl4, Zfp668, Fam129b, Nab2, Txnip, Id1, Cdc42ep3, Dusp6 and Myc, ranked from the most overexpressed to the most under-expressed. Some of them were previously described as over or under-expressed in NP exposed cell systems. We validated in our laboratory an easy-to-use device and a physiological relevant paradigm for studying the effects of cell exposure to TiO2. Ccl4 gene expression seems to be a positive marker of exposure evidenced as well as in vivo or in both in vitro conditions.

Expression of recombinant classical swine fever virus E2 glycoprotein by endogenous Txnip promoter in stable transgenic CHO cells

As the main immunogen that could stimulate neutralized antibody in pigs, recombinant E2 protein of CSFV was expressed in CHO-dhfr-cells driven by endogenous Txnip promoter from Chinese hamster. Different fragments of Txnip promoter were amplified by PCR from isolated genomic DNA of CHO cells and cloned into different expression vectors. Compared with CMV promoter, CHO-pTxnip-4-rE2 (F12) cell clone with the highest yield of rE2 protein was established by random insertion of the expression cassette driven by 860 bp sequences of Txnip promoter. In combination with treatment of 800 nM MTX for copy amplification of inserted expression cassette, the dynamic expression profile of rE2 protein was observed. Then inducible expression strategy of balance between viable cell density and product yield was conducted by mixed addition of 0.1 mM NADH and 0.1 mM ATP in culture medium at day 3 of batch-wise culture. It could be concluded that Txnip promoter would be a promising alternative promoter for recombinant antigen protein expression in transgenic cells.

A rough Brucella mutant induced macrophage death depends on secretion activity of T4SS, but not on cellular Txnip- and Caspase-2-mediated signaling pathway

Brucella is a facultative intracellular bacterium, dividing into smooth- and rough-type Brucella. Smooth-type Brucella can dissociate into rough mutants with cytotoxicity for macrophages during infection, which is critical for Brucella egress and dissemination. However, the mechanism of cytotoxicity infected by rough Brucella is incomplete. In this study, we verified that a rough-type Brucella (RB14 strain) was cytotoxic for macrophages dependent on Type IV secretion system (T4SS). Two specific T4SS VirB4 and VirB11 mutants were constructed, which affect the secretion of T4SS effectors, but not the expression of T4SS components. Cytotoxicity analysis showed that RB14- induced macrophages death depends on T4SS secretion activity. In a further study, 15 reported T4SS effectors were evaluated in inducing macrophage death using over-expression and transfection methods, the results showed that 15 recombinant strains with over-expression of respective effector were not cytotoxicity. In addition, 10 effectors transfected individually, or co-transfected with five effectors barely induced macrophage death, suggesting that all 15 effectors were not associated with macrophage death. Besides, we also evaluated endoplasmic reticulum (ER) stress, Txnip- or Caspase-2 roles in RB14-induced macrophages death. The results showed that inhibition of ER stress, Caspase or Caspase-2 activation was not associated with RB14-infected macrophages death. The casp2 and txnip knockout cells also showed death when infected by the RB14 strain. In all, the RB14-induced macrophage death depends on the secretion activity of T4SS, but not on ER stress, Txnip- or Caspase-2 signal pathway. This study provides a deep insight for rough Brucella-induced macrophage death, which favors for elucidating Brucella infection lifecycle.

Glucose-6-Phosphate Upregulates Txnip Expression by Interacting With MondoA

The major metabolic fates of glucose in cells are glycolysis and the pentose phosphate pathway, and they share the first step: converting glucose to glucose-6-phosphate (G6P). Here, we show that G6P can be sensed by the transcription factor MondoA/Mlx to modulate Txnip expression. Endogenous knockdown and EMSA (gel migration assay) analyses both confirmed that G6P is the metabolic intermediate that activates the heterocomplex MondoA/Mlx to elicit the expression of Txnip. Additionally, the three-dimensional structure of MondoA is modeled, and the binding mode of G6P to MondoA is also predicted by in silico molecular docking and binding free energy calculation. Finally, free energy decomposition and mutational analyses suggest that certain residues in MondoA, GKL139-141 in particular, mediate its binding with G6P to activate MondoA, which signals the upregulation of the expression of Txnip.

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.

Dataset on the formation of Thioredoxin interacting protein (Txnip) containing redox sensitive high molecular weight nucleoprotein complexes

This dataset is supplementary to the submitted research by Ref. [1]. RNAs were extracted from high molecular weight complexes, prepared with 100 kDa filtration of HEK293 Tet-on cells stably transfected with either F-HA-Txnip-V5-His or control vector. Cells were stimulated with 1 μg/mL doxycycline for 24 h, followed by overnight stimulation with 100 μM 4-thiouridine (4sU), 20 mM glucose, and 1 μM bortezomib for 14h. The extracted RNAs from Txnip overexpressing cells compared with control cells was analyzed by RNA-seq. Differentially expressed mRNAs, long noncoding RNAs (lncRNA) and transcripts of uncertain coding potential (TUCPs) are shown. Gene ontology and KEGG enrichment of these differential expressed RNAs is presented.

HECT E3 Ubiquitin Ligase-Regulated Txnip Degradation Facilitates TLR2-Mediated Inflammation During Group A Streptococcal Infection

Thioredoxin-interacting protein (Txnip) inhibits the activity of thioredoxin (Trx) to modulate inflammatory responses. The burden of inflammation caused by microbial infection is strongly associated with disease severity; however, the role of Txnip in bacterial infection remains unclear. In Group A Streptococcus (GAS)-infected macrophages, Txnip was degraded independent of glucose consumption and streptococcal cysteine protease expression. Treatment with proteasome inhibitors reversed GAS-induced Txnip degradation. The activation of Toll-like receptor 2 (TLR2) initiated Txnip degradation, while no further Txnip degradation was observed in TLR2-deficient bone marrow-derived macrophages. NADPH oxidase-regulated NF-κB activation and pro-inflammatory activation were induced and accompanied by Txnip degradation during GAS infection. Silencing Txnip prompted TLR2-mediated inducible nitric oxide synthase (iNOS)/NO, TNF-α, and IL-6 production whereas the blockage of Txnip degradation by pharmacologically inhibiting the HECT E3 ubiquitin ligase with heclin and AMP-dependent protein kinase with dorsomorphin effectively reduced such effects. Our findings reveal that TLR2/NADPH oxidase-mediated Txnip proteasomal degradation facilitates pro-inflammatory cytokine production during GAS infection.

Enhanced vulnerability to oxidative stress and induction of inflammatory gene expression in 3-phosphoglycerate dehydrogenase-deficient fibroblasts

l‐Serine (l‐Ser) is a necessary precursor for the synthesis of proteins, lipids, glycine, cysteine, d‐serine, and tetrahydrofolate metabolites. Low l‐Ser availability activates stress responses and cell death; however, the underlying molecular mechanisms remain unclear. l‐Ser is synthesized de novo from 3‐phosphoglycerate with 3‐phosphoglycerate dehydrogenase (Phgdh) catalyzing the first reaction step. Here, we show that l‐Ser depletion raises intracellular H₂O₂ levels and enhances vulnerability to oxidative stress in Phgdh‐deficient mouse embryonic fibroblasts. These changes were associated with reduced total glutathione levels. Moreover, levels of the inflammatory markers thioredoxin‐interacting protein and prostaglandin‐endoperoxide synthase 2 were upregulated under l‐Ser‐depleted conditions; this was suppressed by the addition of N‐acetyl‐l‐cysteine. Thus, intracellular l‐Ser deficiency triggers an inflammatory response via increased oxidative stress, and de novo l‐Ser synthesis suppresses oxidative stress damage and inflammation when the external l‐Ser supply is restricted.

Mapping Txnip: Key connexions in progression of diabetic nephropathy

Studies demonstrates the major involvement of inflammatory and apoptotic pathway in the pathophysiology of diabetic nephropathy. The cross talk between inflammatory and apoptotic pathway suggests Txnip as a molecular connexion in progression of disease state. Txnip modulates inflammatory pathway (via ROS production and NLRP3 inflammasome activity) and apoptotic pathway (via mTOR pathway). The key contribution of Txnip in both the pathways, reflects, its crucial role in diabetic nephropathy. In the present review, we have first provided an overview of diabetic nephropathy and Txnip system, followed by the mechanistic insight of Txnip in the progression of diabetic nephropathy. This new mechanistic approach suggests to explore Txnip modulators as a promising therapeutic drug target in diabetic nephropathy.

Diabetes regulates fructose absorption through thioredoxin-interacting protein

Metabolic studies suggest that the absorptive capacity of the small intestine for fructose is limited, though the molecular mechanisms controlling this process remain unknown. Here we demonstrate that thioredoxin-interacting protein (Txnip), which regulates glucose homeostasis in mammals, binds to fructose transporters and promotes fructose absorption by the small intestine. Deletion of Txnip in mice reduced fructose transport into the peripheral bloodstream and liver, as well as the severity of adverse metabolic outcomes resulting from long-term fructose consumption. We also demonstrate that fructose consumption induces expression of Txnip in the small intestine. Diabetic mice had increased expression of Txnip in the small intestine as well as enhanced fructose uptake and transport into the hepatic portal circulation. The deletion of Txnip in mice abolished the diabetes-induced increase in fructose absorption. Our results indicate that Txnip is a critical regulator of fructose metabolism and suggest that a diabetic state can promote fructose uptake.

Thioredoxin/Txnip: redoxisome, as a redox switch for the pathogenesis of diseases

During the past few decades, it has been widely recognized that Reduction-Oxidation (redox) responses occurring at the intra- and extra-cellular levels are one of most important biological phenomena and dysregulated redox responses are involved in the initiation and progression of multiple diseases. Thioredoxin1 (Trx1) and Thioredoxin2 (Trx2), mainly located in the cytoplasm and mitochondria, respectively, are ubiquitously expressed in variety of cells and control cellular reactive oxygen species by reducing the disulfides into thiol groups. Thioredoxin interacting protein (Txnip/thioredoxin binding protein-2/vitamin D3 upregulated protein) directly binds to Trx1 and Trx2 (Trx) and inhibit the reducing activity of Trx through their disulfide exchange. Recent studies have revealed that Trx1 and Txnip are involved in some critical redox-dependent signal pathways including NLRP-3 inflammasome activation in a redox-dependent manner. Therefore, Trx/Txnip, a redox-sensitive signaling complex is a regulator of cellular redox status and has emerged as a key component in the link between redox regulation and the pathogenesis of diseases. Here, we review the novel functional concept of the redox-related protein complex, named “Redoxisome,” consisting of Trx/Txnip, as a critical regulator for intra- and extra-cellular redox signaling, involved in the pathogenesis of various diseases such as cancer, autoimmune disease, and diabetes.

A Txnrd1-dependent metabolic switch alters hepatic lipogenesis, glycogen storage, and detoxification

Besides helping to maintain a reducing intracellular environment, the thioredoxin (Trx) system impacts bioenergetics and drug metabolism. We show that hepatocyte-specific disruption of Txnrd1, encoding Trx reductase-1 (TrxR1), causes a metabolic switch in which lipogenic genes are repressed and periportal hepatocytes become engorged with glycogen. These livers also overexpress machinery for biosynthesis of glutathione and conversion of glycogen into UDP-glucuronate; they stockpile glutathione-S-transferases and UDP-glucuronyl-transferases; and they overexpress xenobiotic exporters. This realigned metabolic profile suggested that the mutant hepatocytes might be preconditioned to more effectively detoxify certain xenobiotic challenges. Hepatocytes convert the pro-toxin acetaminophen (APAP, paracetamol) into cytotoxic N-acetyl-p-benzoquinone imine (NAPQI). APAP defenses include glucuronidation of APAP or glutathionylation of NAPQI, allowing removal by xenobiotic exporters. We found that NAPQI directly inactivates TrxR1, yet Txnrd1-null livers were resistant to APAP-induced hepatotoxicity. Txnrd1-null livers did not have more effective gene expression responses to APAP challenge; however, their constitutive metabolic state supported more robust GSH biosynthesis, glutathionylation, and glucuronidation systems. Following APAP challenge, this effectively sustained the GSH system and attenuated damage.