Temporal coordination of the transcription factor response to H2O2 stress.

Oxidative stress from excess H2O2 activates transcription factors that restore redox balance and repair oxidative damage. Although many transcription factors are activated by H2O2, it is unclear whether they are activated at the same H2O2 concentration, or time. Dose-dependent activation is likely as oxidative stress is not a singular state and exhibits dose-dependent outcomes including cell-cycle arrest and cell death. Here, we show that transcription factor activation is both dose-dependent and coordinated over time. Low levels of H2O2 activate p53, NRF2 and JUN. Yet under high H2O2, these transcription factors are repressed, and FOXO1, NF-κB, and NFAT1 are activated. Time-lapse imaging revealed that the order in which these two groups of transcription factors are activated depends on whether H2O2 is administered acutely by bolus addition, or continuously through the glucose oxidase enzyme. Finally, we provide evidence that 2-Cys peroxiredoxins control which group of transcription factors are activated.

SOX11/PRDX2 axis modulates redox homeostasis and chemoresistance in aggressive mantle cell lymphoma.

Mantle cell lymphoma (MCL) is an incurable B-cell neoplasm characterized by an aggressive behavior, short responses to conventional therapies and SOX11 overexpression, which is associated with aggressive disease features and inferior clinical outcome of patients. Oxidative stress is known to induce tumorigenesis and tumor progression, whereas high expression levels of antioxidant genes have been associated with chemoresistance in different cancers. However, the role of oxidative stress in MCL pathogenesis and the involvement of SOX11 regulating redox homeostasis in MCL cells are largely unknown. Here, by integrating gene set enrichment analysis of two independent series of MCL, we observed that SOX11+ MCL had higher reactive oxygen species (ROS) levels compared to SOX11- MCL primary tumors and increased expression of Peredoxine2 (PRDX2), which upregulation significantly correlated with SOX11 overexpression, higher ROS production and worse overall survival of patients. SOX11 knockout (SOX11KO) significantly reduced PRDX2 expression, and SOX11KO and PRDX2 knockdown (PRDX2KD) had increased ROS levels and ROS-mediated tumor cell death upon treatment with drugs, compared to control MCL cell lines. Our results suggest an aberrant redox homeostasis associated with chemoresistance in aggressive MCL through SOX11-mediated PRDX2 upregulation, highlighting PRDX2 as promising target for new therapeutic strategies to overcome chemoresistance in aggressive MCLs.

Intracerebral hemorrhage-induced brain injury in mice: The role of peroxiredoxin 2-Toll-like receptor 4 inflammatory axis.

BACKGROUND: Peroxiredoxin 2 (Prx2), an intracellular protein that regulates redox reactions, released from red blood cells is involved in inflammatory brain injury after intracerebral hemorrhage (ICH). Toll-like receptor 4 (TLR4) may be crucial in this process. This study investigated the role of the Prx2-TLR4 inflammatory axis in brain injury following experimental ICH in mice. METHODS: First, C57BL/6 mice received an intracaudate injection of autologous arterial blood or saline and their brains were harvested on day 1 to measure Prx2 levels. Second, mice received an intracaudate injection of either recombinant mouse Prx2 or saline. Third, the mice were co-injected with autologous arterial blood and conoidin A, a Prx2 inhibitor, or vehicle. Fourth, the mice received a Prx2 injection and were treated with TAK-242, a TLR4 antagonist, or saline (intraperitoneally). Behavioral tests, magnetic resonance imaging, western blot, immunohistochemistry/immunofluorescence staining, and RNA sequencing (RNA-seq) were performed. RESULTS: Brain Prx2 levels were elevated after autologous arterial blood injection. Intracaudate injection of Prx2 caused brain swelling, microglial activation, neutrophil infiltration, neuronal death, and neurological deficits. Co-injection of conoidin A attenuated autologous arterial blood-induced brain injury. TLR4 was expressed on the surface of microglia/macrophages and neutrophils and participated in Prx2-induced inflammation. TAK-242 treatment attenuated Prx2-induced inflammation and neurological deficits. CONCLUSIONS: Prx2 can cause brain injury following ICH through the TLR4 pathway, revealing the Prx2-TLR4 inflammatory axis as a potential therapeutic target.

The cytosolic hyperoxidation-sensitive and -robust Leishmania peroxiredoxins cPRX1 and cPRX2 are both dispensable for parasite infectivity.

Typical two-cysteine peroxiredoxins (2-Cys-PRXs) are H2O2-metabolizing enzymes whose activity relies on two cysteine residues. Protists of the family Trypanosomatidae invariably express one cytosolic 2-Cys-PRX (cPRX1). However, the Leishmaniinae sub-family features an additional isoform (cPRX2), almost identical to cPRX1, except for the lack of an elongated C-terminus with a Tyr-Phe (YF) motif. Previously, cytosolic PRXs were considered vital components of the trypanosomatid antioxidant machinery. Here, we shed new light on the properties, functions and relevance of cPRXs from the human pathogen Leishmania infantum. We show first that LicPRX1 is sensitive to inactivation by hyperoxidation, mirroring other YF-containing PRXs participating in redox signaling. Using genetic fusion constructs with roGFP2, we establish that LicPRX1 and LicPRX2 can act as sensors for H2O2 and oxidize protein thiols with implications for signal transduction. Third, we show that while disrupting the LicPRX-encoding genes increases susceptibility of L. infantum promastigotes to external H2O2in vitro, both enzymes are dispensable for the parasites to endure the macrophage respiratory burst, differentiate into amastigotes and initiate in vivo infections. This study introduces a novel perspective on the functions of trypanosomatid cPRXs, exposing their dual roles as both peroxidases and redox sensors. Furthermore, the discovery that Leishmania can adapt to the absence of both enzymes has significant implications for our understanding of Leishmania infections and their treatment. Importantly, it questions the conventional notion that the oxidative response of macrophages during phagocytosis is a major barrier to infection and the suitability of cPRXs as drug targets for leishmaniasis.

DDAH1 recruits peroxiredoxin 1 and sulfiredoxin 1 to preserve its activity and regulate intracellular redox homeostasis.

Growing evidence suggests that dimethylarginine dimethylaminohydrolase 1 (DDAH1), a crucial enzyme for the degradation of asymmetric dimethylarginine (ADMA), is closely related to oxidative stress during the development of multiple diseases. However, the underlying mechanism by which DDAH1 regulates the intracellular redox state remains unclear. In the present study, DDAH1 was shown to interact with peroxiredoxin 1 (PRDX1) and sulfiredoxin 1 (SRXN1), and these interactions could be enhanced by oxidative stress. In HepG2 cells, H2O2-induced downregulation of DDAH1 and accumulation of ADMA were attenuated by overexpression of PRDX1 or SRXN1 but exacerbated by knockdown of PRDX1 or SRXN1. On the other hand, DDAH1 also maintained the expression of PRDX1 and SRXN1 in H2O2-treated cells. Furthermore, global knockout of Ddah1 (Ddah1-/-) or liver-specific knockout of Ddah1 (Ddah1HKO) exacerbated, while overexpression of DDAH1 alleviated liver dysfunction, hepatic oxidative stress and downregulation of PRDX1 and SRXN1 in CCl4-treated mice. Overexpression of liver PRDX1 improved liver function, attenuated hepatic oxidative stress and DDAH1 downregulation, and diminished the differences between wild type and Ddah1-/- mice after CCl4 treatment. Collectively, our results suggest that the regulatory effect of DDAH1 on cellular redox homeostasis under stress conditions is due, at least in part, to the interaction with PRDX1 and SRXN1.

Cisplatin Induces Kidney Cell Death via ROS-dependent MAPK Signaling Pathways by Targeting Peroxiredoxin I and II in African Green Monkey (Chlorocebus aethiops sabaeus) Kidney Cells.

BACKGROUND/AIM: Cisplatin [cis-diamminedichloroplatinum(II), CDDP] is a widely used and effective antitumor drug in clinical settings, notorious for its nephrotoxic side effects. This study investigated the mechanisms of CDDP-induced damage in African green monkey kidney (Vero) cells, with a focus on the role of Peroxiredoxin I (Prx I) and Peroxiredoxin II (Prx II) of the peroxiredoxin (Prx) family, which scavenge reactive oxygen species (ROS). MATERIALS AND METHODS: We utilized the Vero cell line derived from African green monkey kidneys and exposed these cells to various concentrations of CDDP. Cell viability, apoptosis, ROS levels, and mitochondrial membrane potential were assessed. RESULTS: CDDP significantly compromised Vero cell viability by elevating both cellular and mitochondrial ROS, which led to increased apoptosis. Pretreatment with the ROS scavenger N-acetyl-L-cysteine (NAC) effectively reduced CDDP-induced ROS accumulation and subsequent cell apoptosis. Furthermore, CDDP reduced Prx I and Prx II levels in a dose- and time-dependent manner. The inhibition of Prx I and II exacerbated cell death, implicating their role in CDDP-induced accumulation of cellular ROS. Additionally, CDDP enhanced the phosphorylation of MAPKs (p38, ERK, and JNK) without affecting AKT. The inhibition of these pathways significantly attenuated CDDP-induced apoptosis. CONCLUSION: The study highlights the involvement of Prx proteins in CDDP-induced nephrotoxicity and emphasizes the central role of ROS in cell death mediation. These insights offer promising avenues for developing clinical interventions to mitigate the nephrotoxic effects of CDDP.

Implications and progression of peroxiredoxin 2 (PRDX2) in various human diseases.

Peroxiredoxin 2 (PRDX2), a characteristic 2-Cys enzyme is one of the foremost effective scavenger proteins against reactive oxygen species (ROS) and hydrogen peroxide (H2O2) defending cells against oxidative stress. Dysregulation of this antioxidant raises the quantity of ROS and oxidative stress implicated in several diseases. PRDX2 lowers the generation of ROS that takes part in controlling several signalling pathways occurring in neurons, protecting them from stress caused by oxidation and an inflammatory harm. Depending on the aetiological variables, the kind of cancer, and the stage of tumour development, PRDX2 may behave either as an onco-suppressor or a promoter. However, overexpression of PRDX2 may be linked to the development of numerous cancers, including those of the colon, cervix, breast, and prostate. PRDX2 also plays a beneficial effect in inflammatory diseases. PRDX2 being a thiol-specific peroxidase, is known to control proinflammatory reactions. The spilling of PRDX2, on the other hand, accelerates cognitive impairment following a stroke by triggering an inflammatory reflex. PRDX2 expression patterns in vascular cells tend to be crucial to its involvement in cardiovascular diseases. In vascular smooth muscle cells, if the protein tyrosine phosphatase is restricted, PRDX2 could avoid the neointimal thickening which relies on platelet derived growth factor (PDGF), a vital component of vascular remodelling. A proper PRDX2 balance is therefore crucial. The imbalance causes a number of illnesses, including cancers, inflammatory diseases, cardiovascular ailments, and neurological and neurodegenerative problems which are discussed in this review.

PRDX2 regulates stemness contributing to cisplatin resistance and metastasis in bladder cancer.

BACKGROUND: Cisplatin (CDDP)-based chemotherapy has emerged as the primary treatment for muscle-invasive bladder cancer and metastatic bladder cancer. Nevertheless, a significant proportion of patients experience rapidly developed chemoresistance, leading to treatment ineffectiveness. Existing evidence suggests that chemoresistance is governed by various factors, including tumor stem cells, epithelial mesenchymal transition, and reactive oxygen species (ROS). However, limited research has been conducted on the role of PRDX2, a crucial ROS scavenger, in the modulation of chemoresistance in bladder cancer. METHODS: Cisplatin-resistant cell lines were established using the concentration gradient overlay method, and differentially expressed genes in resistant cells were screened through RNA sequencing. The expression of PRDX2 in cells and tissues was assessed using RT-qPCR, Western Blot, and immunohistochemistry. The expression of PRDX2 in bladder cancer and adjacent tissues was evaluated using a bladder cancer tissue microarray. Furthermore, the impact of PRDX2 knockdown on tumor formation and metastasis was investigated in vivo by applying subcutaneous tumor xenografts tail vein metastasis assays. RESULTS: We demonstrated that PRDX2 is significantly upregulated in bladder tumors and cisplatin-resistant bladder tumor cell lines. Overexpression of PRDX2 can promote tumor proliferation, migration, and invasion both in vitro and in vivo. We have found that knockdown of PRDX2 expression can effectively reverse cell resistance to cisplatin. Mechanistically, our findings suggest that PRDX2 is involved in regulating tumor stemness and epithelial-mesenchymal transition (EMT). Knockdown of PRDX2 affects the PI3K-AKT and mTOR signaling pathways, thereby influencing tumor stemness and EMT, ultimately impacting the chemotherapy resistance of the tumor. CONCLUSIONS: This study provides a new insight into the regulation of chemotherapy resistance in bladder cancer by PRDX2. Targeting PRDX2 can serve as a potent therapeutic target for chemotherapy resistance.

MiR-92a-2-5p suppresses esophageal squamous cell carcinoma cell proliferation and invasion by targeting PRDX2.

MicroRNAs (miRNAs) can function as negative regulators of gene expression by binding to the 3'-untranslated region (3'-UTR) of target genes. The aberrant expression of miRNAs in neoplasm is extensively associated with tumorigenesis and cancer progression, including esophageal squamous cell carcinoma (ESCC). Our previous investigation has identified the oncogenic roles of Peroxiredoxin2 (PRDX2) in ESCC progression; however, its upstream regulatory mechanism remains to be elucidated. By merging the prediction results from miRWalk2.0 and miRNA differential expression analysis results based on The Cancer Genome Atlas Esophageal Carcinoma (TCGA-ESCA) database, eight miRNA candidates were predicted to be the potential regulatory miRNAs of PRDX2, followed by further identification of miR-92a-2-5p as the putative miRNA of PRDX2. Subsequent functional studies demonstrated that miR-92a-2-5p can suppress ESCC cell proliferation and migration, as well as tumor growth in subcutaneous tumor xenograft models, which might be mediated by the suppression of AKT/mTOR and Wnt3a/ß-catenin signaling pathways upon miR-92a-2-5p mimic transfection condition. These data revealed the tumor suppressive functions of miR-92a-2-5p in ESCC by targeting PRDX2.

Functions of Peroxiredoxins and Their Roles in Autoimmune Diseases.

Significance: Oxidative stress is a common feature of autoimmune diseases. Low levels of reactive oxygen species (ROS) generation are important for various biological processes. Redox homeostasis can be disrupted when there is an imbalance between the production of ROS and the detoxification effect of antioxidants. Peroxiredoxins (PRDXs) are essential regulators of cellular redox signaling. Recent Advances: PRDXs are widely expressed antioxidant enzymes, and their physiological role is mainly to remove excess ROS in cells and reduce oxidative stress. Recent studies have shown that almost all PRDX subtypes are involved in the development of autoimmune diseases. Critical Issues: The pathogenesis of autoimmune diseases is complex, and effective treatments are lacking. Therefore, there is an urgent need to find new therapeutic targets. In this review, we discuss the functions of PRDXs and their pathophysiological roles in several autoimmune diseases. PRDXs may serve as potential targets for the treatment of autoimmune diseases. Future Directions: PRDXs are important in oxidative stress-mediated pathological situations. Future in-depth exploration of the mechanisms involved in regulating PRDXs in autoimmune diseases is needed to develop strategies targeting PRDXs for the treatment of autoimmune diseases. Antioxid. Redox Signal. 40, 329-344.

Dual role of PRDX1 in redox-regulation and tumorigenesis: Past and future.

Tumour cells often display an active metabolic profile, leading to the intracellular accumulation of reactive oxygen species. As a member of the peroxidase family, peroxiredoxin 1 (PRDX1) functions generally in protecting against cell damage caused by H2O2. Additionally, PRDX1 plays a role as a molecular chaperone in various malignant tumours, exhibiting either tumour-promoting or tumour-suppressing effects. Currently, PRDX1-targeting drugs have demonstrated in vitro anticancer effects, indicating the potential of PRDX1 as a molecular target. Here we discussed the diverse functions of PRDX1 in tumour biology and provided a comprehensive analysis of the therapeutic potential of targeting PRDX1 signalling across various types of cancer.

Peroxiredoxin-2 gene in Antheraea pernyi modulates immune functions and protect DNA damage.

Peroxiredoxins have been shown to protect insects from oxidative damage and to play a role in the immune system. In the present study, we cloned and characterized the Antheraea pernyi peroxiredoxin 2 (ApPrx-2) gene, then assessed its functional roles. The ApPrx-2 gene has a 687 bp open reading frame that encodes a protein with 288 amino acid residues. Quantitative real-time PCR analysis revealed that the mRNA levels of ApPrx-2 were highest in the hemocytes. Immune challenge assay revealed that ApPrx-2 transcription could be induced after microbial challenge. A DNA cleavage assay employing recombinant ApPrx-2 protein and a metal-catalyzed oxidation system showed that rApPrx-2 protein could protect supercoiled DNA against oxidative stress. The protein antioxidant activity of rApPrx-2 was examined, and it was found that rApPrx-2 exhibited a high level of antioxidant activity by removing H2O2. In addition, ApPrx-2 knockdown larvae had higher H2O2 levels and a lower survival rate when compared to controls. Interestingly, the antibacterial activity was significantly higher in ApPrx-2 depleted larvae compared with control. Overall, our findings indicate that ApPrx-2 may be involved in a range of physiological functions of A. pernyi, as it protects supercoiled DNA from oxidative stress and regulates antibacterial activity.

Systematic analysis of Prx genes in the Brachypodium genus and their expression pattern under abiotic constraints.

Peroxiredoxins (Prx) are ubiquitous peroxidases required for the removal of excess free radicals produced under stress conditions. Peroxiredoxin genes (Prx) in the Brachypodium genus were identified using bioinformatics tools and their expression profiles were determined under abiotic stress using RT-qPCR. The promoter regions of Prx genes contain several cis-acting elements related to stress response. In silico expression analysis showed that B. distachyon Prx genes (BdPrx) are tissue specific. RT-qPCR analysis revealed their differential expression when exposed to salt or PEG-induced dehydration stress. In addition, the upregulation of BdPrx genes was accompanied by accumulation of H2 O2 . Exogenous application of H2 O2 induced expression of almost all BdPrx genes. The identified molecular interaction network indicated that Prx proteins may contribute to abiotic stress tolerance by regulating key enzymes involved in lignin biosynthesis. Overall, our findings suggest the potential role of Prx genes in abiotic stress tolerance and lay the foundation for future functional analyses aiming to engineer genetically improved cereal lines.

Kinetic and structural assessment of the reduction of human 2-Cys peroxiredoxins by thioredoxins.

We have studied the reduction reactions of two cytosolic human peroxiredoxins (Prx) in their disulfide form by three thioredoxins (Trx; two human and one bacterial), with the aim of better understanding the rate and mechanism of those reactions, and their relevance in the context of the catalytic cycle of Prx. We have developed a new methodology based on stopped-flow and intrinsic fluorescence to study the bimolecular reactions, and found rate constants in the range of 105 -106 m-1 s-1 in all cases, showing that there is no marked kinetic preference for the expected Trx partner. By combining experimental findings and molecular dynamics studies, we found that the reactivity of the nucleophilic cysteine (CN ) in the Trx is greatly affected by the formation of the Prx-Trx complex. The protein-protein interaction forces the CN thiolate into an unfavorable hydrophobic microenvironment that reduces its hydration and results in a remarkable acceleration of the thiol-disulfide exchange reactions by more than three orders of magnitude and also produces a measurable shift in the pKa of the CN . This mechanism of activation of the thiol disulfide exchange may help understand the reduction of Prx by alternative reductants involved in redox signaling.

Serum peroxiredoxin-4, a biomarker of oxidative stress, is associated with the development of nephropathy in patients with type 2 diabetes (Zodiac-65).

Oxidative stress is implicated in the development and progression of type 2 diabetes (T2D). Peroxiredoxin-4 is an antioxidant protein, which may serve as biomarker of oxidative stress, and has previously been associated with new-onset T2D. In this study, we investigated associations between circulating peroxiredoxin-4 and the risk of developing new-onset microvascular complications in T2D patients. Serum peroxiredoxin-4 was measured in 536 patients with T2D with (n = 257) and without (n = 279) baseline microvascular complications who participated in a primary-care based cohort study (Zwolle Outpatient Diabetes project Integrating Available Care [ZODIAC] study). Over a median follow-up of 3.4 years, 38 (13.6%) developed nephropathy, defined as albuminuria in two consecutive urine samples. In multivariable Cox proportional hazards regression analyses, peroxiredoxin-4 was associated with new-onset nephropathy (hazard ratio [HR] per doubling 1.78 [95% CI: 1.27-2.49], P < 0.001) after adjustment for potential confounding factors, including age, sex, disease duration, HbA1c levels, macrovascular complications, systolic blood pressure, and even high-sensitive C-reactive protein. There was no interaction of peroxiredoxin-4 with hs-CRP impacting on new-onset nephropathy. No significant associations were found with new-onset retinopathy or neuropathy. In conclusion, circulating peroxiredoxin-4 associates positively with an increased risk of developing nephropathy in T2D independent and irrespective of low-grade inflammation.

Identification of PRDX5 as A Target for The Treatment of Castration-Resistant Prostate Cancer.

Treatment of castration-resistant prostate cancer (CRPC) is a long-standing clinical challenge. Traditionally, CRPC drugs work by either reducing dihydrotestosterone biosynthesis or blocking androgen receptor (AR) signaling. Here it is demonstrated that AR inhibitor treatment gives rise to a drug-tolerant persister (DTP) state. The thioredoxin/peroxiredoxin pathway is up-regulated in DTP cells. Peroxiredoxin 5 (PRDX5) promotes AR inhibitor resistance and CRPC development. Inhibition of PRDX5 suppresses DTP cell proliferation in culture, dampens CRPC development in animal models, and stabilizes PSA progression and metastatic lesions in patients. Therefore, the study provides a novel mechanism and potential target for the management of castration-resistant prostate cancer.

Hepatocytes-derived Prdx1 regulates macrophage phenotypes via TLR4 activation in acute liver injury.

Acute liver injury (ALI) is a significant causative factor for multiple hepatic diseases. The excessive inflammatory response triggers proinflammatory immune cells recruitment, infiltration and differentiation, further contributing to inflammatory injuries in liver. As a proinflammatory factor, circulating Peroxiredoxin 1 (Prdx1) is elevated in ALI patients and mice. In this study, through carbon tetrachloride (CCl4) and cecal puncture and ligation (CLP)-induced liver injury mice model, we found hepatocytes-derived Prdx1 expression was increased in ALI. After AAV8-Prdx1-mediated Prdx1 knockdown, CCl4 and CLP-induced ALI was alleviated, along with the reduced proinflammatory cytokines, suppressed myeloid cells recruitment, decreased proportions of hepatic macrophages and neutrophils, restrained proinflammatory macrophage differentiation and infiltration. Mechanistically, hepatocyte-derived Prdx1 regulated macrophages through paracrine activation of the TLR4 signal. Our data support the immune and inflammatory regulatory role of Prdx1 in ALI pathological process to suggest its potential therapeutic application and clinical value.

The architecture of redox microdomains: Cascading gradients and peroxiredoxins' redox-oligomeric coupling integrate redox signaling and antioxidant protection.

In the cytosol of human cells under low oxidative loads, hydrogen peroxide is confined to microdomains around its supply sites, due to its fast consumption by peroxiredoxins. So are the sulfenic and disulfide forms of the 2-Cys peroxiredoxins, according to a previous theoretical analysis [Travasso et al., Redox Biology 15 (2017) 297]. Here, an extended reaction-diffusion model that for the first time considers the differential properties of human peroxiredoxins 1 and 2 and the thioredoxin redox cycle predicts important new aspects of the dynamics of redox microdomains. The peroxiredoxin 1 sulfenates and disulfides are more localized than the corresponding peroxiredoxin 2 forms, due to the former peroxiredoxin's faster resolution step. The thioredoxin disulfides are also localized. As the H2O2 supply rate (vsup) approaches and then surpasses the maximal rate of the thioredoxin/thioredoxin reductase system (V), these concentration gradients become shallower, and then vanish. At low vsup the peroxiredoxin concentration determines the H2O2 concentrations and gradient length scale, but as vsup approaches V, the thioredoxin reductase activity gains influence. A differential mobility of peroxiredoxin disulfide dimers vs. reduced decamers enhances the redox polarity of the cytosol: as vsup approaches V, reduced decamers are preferentially retained far from H2O2 sources, attenuating the local H2O2 buildup. Substantial total protein concentration gradients of both peroxiredoxins emerge under these conditions, and the concentration of reduced peroxiredoxin 1 far from the H2O2 sources even increases with vsup. Altogether, the properties of 2-Cys peroxiredoxins and thioredoxin are such that localized H2O2 supply induces a redox and functional polarization between source-proximal regions (redox microdomains) that facilitate peroxiredoxin-mediated signaling and distal regions that maximize antioxidant protection.

Altered Regulation of the Glucose Transporter GLUT3 in PRDX1 Null Cells Caused Hypersensitivity to Arsenite.

Targeting tumour metabolism through glucose transporters is an attractive approach. However, the role these transporters play through interaction with other signalling proteins is not yet defined. The glucose transporter SLC2A3 (GLUT3) is a member of the solute carrier transporter proteins. GLUT3 has a high affinity for D-glucose and regulates glucose uptake in the neurons, as well as other tissues. Herein, we show that GLUT3 is involved in the uptake of arsenite, and its level is regulated by peroxiredoxin 1 (PRDX1). In the absence of PRDX1, GLUT3 mRNA and protein expression levels are low, but they are increased upon arsenite treatment, correlating with an increased uptake of glucose. The downregulation of GLUT3 by siRNA or deletion of the gene by CRISPR cas-9 confers resistance to arsenite. Additionally, the overexpression of GLUT3 sensitises the cells to arsenite. We further show that GLUT3 interacts with PRDX1, and it forms nuclear foci, which are redistributed upon arsenite exposure, as revealed by immunofluorescence analysis. We propose that GLUT3 plays a role in mediating the uptake of arsenite into cells, and its homeostatic and redox states are tightly regulated by PRDX1. As such, GLUT3 and PRDX1 are likely to be novel targets for arsenite-based cancer therapy.

Comparative Genomic and Transcriptomic Analysis of Phenol Degradation and Tolerance in Acinetobacter lwoffii through Adaptive Evolution.

Microorganism-based methods have been widely applied for the treatment of phenol-polluted environments. The previously isolated Acinetobacter lwoffii NL1 strain could completely degrade 0.5 g/L phenol within 12 h, but not higher concentrations of phenol. In this study, we developed an evolutionary strain NL115, through adaptive laboratory evolution, which possessed improved degradation ability and was able to degrade 1.5 g/L phenol within 12 h. Compared with that of the starting strain NL1, the concentration of degradable phenol by the developed strain increased three-fold; its phenol tolerance was also enhanced. Furthermore, comparative genomics showed that sense mutations mainly occurred in genes encoding alkyl hydroperoxide reductase, phenol hydroxylase, 30S ribosomal protein, and mercury resistance operon. Comparative transcriptomics between A. lwoffii NL115 and NL1 revealed the enrichment of direct degradation, stress resistance, and vital activity processes among the metabolic responses of A. lwoffii adapted to phenol stress. Among these, all the upregulated genes (log2fold-change > 5) encoded peroxidases. A phenotypic comparison of A. lwoffii NL1 and NL115 found that the adapted strain NL115 exhibited strengthened antioxidant capacity. Furthermore, the increased enzymatic activities of phenol hydroxylase and alkyl hydroperoxide reductase in A. lwoffii NL115 validated their response to phenol. Overall, this study provides insight into the mechanism of efficient phenol degradation through adaptive microbial evolution and can help to drive improvements in phenol bioremediation.