Thioredoxin-1 Promotes Anti-Inflammatory Macrophages of the M2 Phenotype and Antagonizes Atherosclerosis

Disulfide stress and its role in cardiovascular diseases

Cardiovascular disease (CVD) is one of the leading causes of mortality in humans, and oxidative stress plays a pivotal role in disease progression. This phenomenon typically arises from weakening of the cellular antioxidant system or excessive accumulation of peroxides. This review focuses on a specialized form of oxidative stress-disulfide stress-which is triggered by an imbalance in the glutaredoxin and thioredoxin antioxidant systems within the cell, leading to the accumulation of disulfide bonds. The genesis of disulfide stress is usually induced by extrinsic pathological factors that disrupt the thiol-dependent antioxidant system, manifesting as sustained glutathionylation of proteins, formation of abnormal intermolecular disulfide bonds between cysteine-rich proteins, or irreversible oxidation of thiol groups to sulfenic and sulfonic acids. Disulfide stress not only precipitates the collapse of the antioxidant system and the accumulation of reactive oxygen species, exacerbating oxidative stress, but may also initiate cellular inflammation, autophagy, and apoptosis through a cascade of signaling pathways. Furthermore, this review explores the detrimental effects of disulfide stress on the progression of various CVDs including atherosclerosis, hypertension, myocardial ischemia-reperfusion injury, diabetic cardiomyopathy, cardiac hypertrophy, and heart failure. This review also proposes several potential therapeutic avenues to improve the future treatment of CVDs.

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

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

Albumin-fused thioredoxin ameliorates high-fat diet-induced non-alcoholic steatohepatitis

The pathogenesis of non-alcoholic steatohepatitis (NASH) involves the simultaneous interaction of multiple factors such as lipid accumulation, oxidative stress, and inflammatory response. Here, the effect of human serum albumin (HSA) fused to thioredoxin (Trx) on NASH was investigated. Trx is known to have anti-oxidative, anti-inflammatory, and anti-apoptotic effects. However, Trx is a low molecular weight protein and is rapidly eliminated from the blood. To overcome the low availability of Trx, HSA-Trx fusion protein was produced and evaluated the therapeutic effect on high-fat diet (HFD)-induced NASH model mice. HSA-Trx administered before the formation of NASH pathology showed it to have a preventive effect. Specifically, HSA-Trx was found to prevent the pathological progression to NASH by suppressing lipid accumulation, liver injury markers, and liver fibrosis. When HSA-Trx was administered during the early stage of NASH there was a marked reduction in lipid accumulation, inflammation, and fibrosis in the liver, indicating that HSA-Trx ameliorates NASH pathology. The findings indicate that HSA-Trx influences multiple pathological factors, such as oxidative stress, inflammation, and apoptosis, to elicit a therapeutic benefit. HSA-Trx also inhibited palmitic acid-induced lipotoxicity in HepG2 cells. Taken together, these results indicate that HSA-Trx has potential as a therapeutic agent for NASH pathology.

Macrophage-expressed SRA ameliorates alcohol-induced liver injury by suppressing S-glutathionylation of Notch1 via recruiting thioredoxin

Scavenger receptor A (SRA) is preferentially expressed in macrophages and implicated as a multifunctional pattern recognition receptor for innate immunity. Hepatic macrophages play a primary role in the pathogenesis of alcoholic liver disease. Herein, we observed that SRA expression was significantly increased in the liver tissues of mice with alcohol-related liver injury. SRA-deficient (SRA-/-) mice developed more severe alcohol-induced liver disease than wild-type mice. Enhanced liver inflammation existed in alcohol-challenged SRA-/- mice and was associated with increased Notch activation in hepatic macrophages compared with wild-type control animals. Mechanistically, SRA directly bound with Notch1 and suppressed its S-glutathionylation, thereby inhibiting Notch pathway activation. Further, we determined that the SRA interacted with thioredoxin-1 (Trx-1), a redox-active protein. SRA inhibited Trx-1 dimerization and facilitated the interaction of Trx-1 with Notch1. Application of a Trx-1-specific inhibitory agent during macrophage stimulation abolished SRA-mediated regulation of the Notch pathway and its downstream targets. In summary, our study revealed that SRA plays a critical role in macrophage inflammatory response by targeting Notch1 for its glutathionylation. SRA-mediated negative regulation of Notch activation might serve as a novel therapeutic strategy for alcohol-induced liver injury.

Thioredoxin-1 and its mimetic peptide improve systolic cardiac function and remodeling after myocardial infarction

Myocardial infarction (MI) is characterized by a significant loss of cardiomyocytes (CMs), and it is suggested that reactive oxygen species (ROS) are involved in cell cycle arrest, leading to impaired CM renewal. Thioredoxin-1 (Trx-1) scavenges ROS and may play a role in restoring CM renewal. However, the truncated form of Trx-1, Trx-80, can compromise its efficacy by exerting antagonistic effects. Therefore, a Trx-1 mimetic peptide called CB3 was tested as an alternative way to restore CMs. This study aimed to investigate the effects of Trx-1, Trx-80, and CB3 on mice with experimental MI and study the underlying mechanism of CB3 on CMs. Mouse cardiac parameters were quantified by echocardiography, and infarction size and fibrosis determined using Trichrome and Picro-Sirius Red staining. The study found that Trx-1 and CB3 improved mouse cardiac function, reduced the size of cardiac infarct and fibrosis, and decreased the expression of cardiac inflammatory markers. Furthermore, CB3 polarized macrophages into M2 phenotype, reduced apoptosis and oxidative stress after MI, and increased CM proliferation in cell culture and in vivo. CB3 effectively protected against myocardial infarction and could represent a new class of compounds for treating MI.

Thioredoxin-1 promotes the restoration of alveolar bone in periodontitis with diabetes

Treatment of periodontitis in people with diabetes remains challenging. The present study aimed to investigate the therapeutic potential of thioredoxin-1 (TRX1) in periodontitis with diabetes, as well as its role in modulating osteogenic differentiation. Our findings indicated that the production of reactive oxygen species (ROS) was elevated, while the expression of TRX1 was significantly reduced in the periodontal tissues of periodontitis mice with diabetes. Furthermore, knockdown of TRX1 in periodontal ligament stem cells (PDLSCs) resulted in the inhibition of osteogenic differentiation through disrupting Wnt/β-catenin signaling. However, this inhibition was restored upon administration of recombinant human TRX1 (rhTRX1). Importantly, rhTRX1 treatment decreased ROS generation, activated Wnt/β-catenin signal pathway and considerably promoted the alveolar bone repair of periodontitis mice with diabetes. These findings highlighted the crucial protective role of TRX1 in periodontitis with diabetes and suggested that it may serve as a potential therapeutic target for refractory periodontitis associated with oxidative stress.

Lipid-laden foam cells in the pathology of atherosclerosis: shedding light on new therapeutic targets

INTRODUCTION

Lipid-laden foam cells within atherosclerotic plaques are key players in all phases of lesion development including its progression, necrotic core formation, fibrous cap thinning, and eventually plaque rupture. Manipulating foam cell biology is thus an attractive therapeutic strategy at early, middle, and even late stages of atherosclerosis. Traditional therapies have focused on prevention, especially lowering plasma lipid levels. Despite these interventions, atherosclerosis remains a major cause of cardiovascular disease, responsible for the largest numbers of death worldwide.

AREAS COVERED

Foam cells within atherosclerotic plaques are comprised of macrophages, vascular smooth muscle cells, and other cell types which are exposed to high concentrations of lipoproteins accumulating within the subendothelial intimal layer. Macrophage-derived foam cells are particularly well studied and have provided important insights into lipid metabolism and atherogenesis. The contributions of foam cell-based processes are discussed with an emphasis on areas of therapeutic potential and directions for drug development.

EXERT OPINION

As key players in atherosclerosis, foam cells are attractive targets for developing more specific, targeted therapies aimed at resolving atherosclerotic plaques. Recent advances in our understanding of lipid handling within these cells provide insights into how they might be manipulated and clinically translated to better treat atherosclerosis.

Prevention of atrial fibrillation after open-chest surgery with extracellular vesicle therapy

Almost half of patients recovering from open-chest surgery experience atrial fibrillation (AF) that results principally from inflammation in the pericardial space surrounding the heart. Given that postoperative AF is associated with increased mortality, effective measures to prevent AF after open-chest surgery are highly desirable. In this study, we tested the concept that extracellular vesicles (EVs) isolated from human atrial explant-derived cells can prevent postoperative AF. Middle-aged female and male rats were randomized to undergo sham operation or induction of sterile pericarditis followed by trans-epicardial injection of human EVs or vehicle into the atrial tissue. Pericarditis increased the probability of inducing AF while EV treatment abrogated this effect in a sex-independent manner. EV treatment reduced infiltration of inflammatory cells and production of pro-inflammatory cytokines. Atrial fibrosis and hypertrophy seen after pericarditis were markedly attenuated by EV pretreatment, an effect attributable to suppression of fibroblast proliferation by EVs. Our study demonstrates that injection of EVs at the time of open-chest surgery shows prominent antiinflammatory effects and prevents AF due to sterile pericarditis. Translation of this finding to patients might provide an effective new strategy to prevent postoperative AF by reducing atrial inflammation and fibrosis.

Schistosoma mansoni egg-derived thioredoxin and Sm14 drive the development of IL-10 producing regulatory B cells

During chronic schistosome infections, a complex regulatory network is induced to regulate the host immune system, in which IL-10-producing regulatory B (Breg) cells play a significant role. Schistosoma mansoni soluble egg antigens (SEA) are bound and internalized by B cells and induce both human and mouse IL-10 producing Breg cells. To identify Breg-inducing proteins in SEA, we fractionated SEA by size exclusion chromatography and found 6 fractions able to induce IL-10 production by B cells (out of 18) in the high, medium and low molecular weight (MW) range. The high MW fractions were rich in heavily glycosylated molecules, including multi-fucosylated proteins. Using SEA glycoproteins purified by affinity chromatography and synthetic glycans coupled to gold nanoparticles, we investigated the role of these glycan structures in inducing IL-10 production by B cells. Then, we performed proteomics analysis on active low MW fractions and identified a number of proteins with putative immunomodulatory properties, notably thioredoxin (SmTrx1) and the fatty acid binding protein Sm14. Subsequent splenic murine B cell stimulations and hock immunizations with recombinant SmTrx1 and Sm14 showed their ability to dose-dependently induce IL-10 production by B cells both in vitro and in vivo. Identification of unique Breg cells-inducing molecules may pave the way to innovative therapeutic strategies for inflammatory and auto-immune diseases.

Clinical Potential of Hydrogen Sulfide in Peripheral Arterial Disease

Peripheral artery disease (PAD) affects more than 230 million people worldwide. PAD patients suffer from reduced quality of life and are at increased risk of vascular complications and all-cause mortality. Despite its prevalence, impact on quality of life and poor long-term clinical outcomes, PAD remains underdiagnosed and undertreated compared to myocardial infarction and stroke. PAD is due to a combination of macrovascular atherosclerosis and calcification, combined with microvascular rarefaction, leading to chronic peripheral ischemia. Novel therapies are needed to address the increasing incidence of PAD and its difficult long-term pharmacological and surgical management. The cysteine-derived gasotransmitter hydrogen sulfide (H₂S) has interesting vasorelaxant, cytoprotective, antioxidant and anti-inflammatory properties. In this review, we describe the current understanding of PAD pathophysiology and the remarkable benefits of H₂S against atherosclerosis, inflammation, vascular calcification, and other vasculo-protective effects.

Collagen type I alters the proteomic signature of macrophages in a collagen morphology-dependent manner

Idiopathic pulmonary fibrosis is a progressive lung disease that causes scarring and loss of lung function. Macrophages play a key role in fibrosis, but their responses to altered morphological and mechanical properties of the extracellular matrix in fibrosis is relatively unexplored. Our previous work showed functional changes in murine fetal liver-derived alveolar macrophages on fibrous or globular collagen morphologies. In this study, we applied differential proteomics to further investigate molecular mechanisms underlying the observed functional changes. Macrophages cultured on uncoated, fibrous, or globular collagen-coated plastic were analyzed by liquid chromatography-mass spectrometry. The presence of collagen affected expression of 77 proteins, while 142 were differentially expressed between macrophages grown on fibrous or globular collagen. Biological process and pathway enrichment analysis revealed that culturing on any type of collagen induced higher expression of enzymes involved in glycolysis. However, this did not lead to a higher rate of glycolysis, probably because of a concomitant decrease in activity of these enzymes. Our data suggest that macrophages sense collagen morphologies and can respond with changes in expression and activity of metabolism-related proteins. These findings suggest intimate interactions between macrophages and their surroundings that may be important in repair or fibrosis of lung tissue.

Tuning macrophages for atherosclerosis treatment

Atherosclerosis is a chronic inflammatory vascular disease and a leading cause of death worldwide. Macrophages play an important role in inflammatory responses, cell-cell communications, plaque growth and plaque rupture in atherosclerotic lesions. Here, we review the sources, functions and complex phenotypes of macrophages in the progression of atherosclerosis, and discuss the recent approaches in modulating macrophage phenotype and autophagy for atherosclerosis treatment. We then focus on the drug delivery strategies that target macrophages or use macrophage membrane-coated particles to deliver therapeutics to the lesion sites. These biomaterial-based approaches that target, modulate or engineer macrophages have broad applications for disease therapies and tissue regeneration.

Physiological and modulatory role of thioredoxins in the cellular function

Thioredoxins (TRXs) are a class of ubiquitous and multifunctional protein. Mammal cells present three isoforms: a cytosolic and extracellular called thioredoxin 1 (TRX1), a mitochondrial (TRX2), and one specific in spermatozoids (TRX3). Besides, a truncated form called TRX80 exists, which results from the post-translational cleavage performed on TRX1. TRXs' main function is to maintain the reduction-oxidation homeostasis of the cell, reducing the proteins through a thiol-disulfide exchange that depends on two cysteines located in the active site of the protein (Cys32-X-X-Cys35 in humans). In addition, TRX1 performs S-nitrosylation, a post-translational modification of proteins that depends on cysteines of its C-terminal region (Cys62, Cys69, and Cys73 in human TRX1). These modifications allow the TRXs to modulate the protein function and participate in regulating diverse cellular processes, such as oxidative stress, transcription, signaling cascades, apoptosis, inflammation, and immunologic response. This points out the crucial relevance of TRXs for cell function, signaling it as a strategic target for the treatment of many diseases and its possible use as a therapeutic factor.

Redox regulation of the immune response

The immune-inflammatory response is associated with increased nitro-oxidative stress. The aim of this mechanistic review is to examine: (a) the role of redox-sensitive transcription factors and enzymes, ROS/RNS production, and the activity of cellular antioxidants in the activation and performance of macrophages, dendritic cells, neutrophils, T-cells, B-cells, and natural killer cells; (b) the involvement of high-density lipoprotein (HDL), apolipoprotein A1 (ApoA1), paraoxonase-1 (PON1), and oxidized phospholipids in regulating the immune response; and (c) the detrimental effects of hypernitrosylation and chronic nitro-oxidative stress on the immune response. The redox changes during immune-inflammatory responses are orchestrated by the actions of nuclear factor-κB, HIF1α, the mechanistic target of rapamycin, the phosphatidylinositol 3-kinase/protein kinase B signaling pathway, mitogen-activated protein kinases, 5' AMP-activated protein kinase, and peroxisome proliferator-activated receptor. The performance and survival of individual immune cells is under redox control and depends on intracellular and extracellular levels of ROS/RNS. They are heavily influenced by cellular antioxidants including the glutathione and thioredoxin systems, nuclear factor erythroid 2-related factor 2, and the HDL/ApoA1/PON1 complex. Chronic nitro-oxidative stress and hypernitrosylation inhibit the activity of those antioxidant systems, the tricarboxylic acid cycle, mitochondrial functions, and the metabolism of immune cells. In conclusion, redox-associated mechanisms modulate metabolic reprogramming of immune cells, macrophage and T helper cell polarization, phagocytosis, production of pro- versus anti-inflammatory cytokines, immune training and tolerance, chemotaxis, pathogen sensing, antiviral and antibacterial effects, Toll-like receptor activity, and endotoxin tolerance.

New insights into macrophage subsets in atherosclerosis

Macrophages in atherosclerotic patients are notably plastic and heterogeneous. Single-cell RNA sequencing (Sc RNA-seq) can provide information about all the RNAs in individual cells, and it is used to identify cell subpopulations in atherosclerosis (AS) and reveal the heterogeneity of these cells. Recently, some findings from Sc RNA-seq experiments have suggested the existence of multiple macrophage subsets in atherosclerotic plaque lesions, and these subsets exhibit significant differences in their gene expression levels and functions. These cells affect various aspects of plaque lesion development, stabilization, and regression, as well as plaque rupture. This article aims to review the content and results of current studies that used RNA-seq to explore the different types of macrophages in AS and the related molecular mechanisms as well as to identify the potential roles of these macrophage types in the pathogenesis of atherosclerotic plaques. Also, this review listed some new therapeutic targets for delaying atherosclerotic lesion progression and treatment based on the experimental results.

Thioredoxin-1 Activation by Pterostilbene Protects Against Doxorubicin-Induced Hepatotoxicity via Inhibiting the NLRP3 Inflammasome

Background: Doxorubicin (DOX) has been widely used in cancer treatment. However, DOX can cause a range of significant side effects, of which hepatotoxicity is a common one, and therefore limits its clinical use. Pterostilbene (PTS) has been shown to exhibit anti-oxidant and anti-inflammatory effects in the treatment of liver diseases but whether PTS could protect against hepatotoxicity in DOX-treated mice is unknown.

Methods: In our study, we use C57/BL6J mice and the HepG2 cell line. We divided the mice in 4 groups: the control, the PTS treatment, the DOX treatment, and the DOX + PTS treatment group. Liver histopathology was judged by performing hematoxylin–eosin and Masson staining. Immunohistochemistry was used to perform the expression of NLRP3. The levels of serum alanine transaminase (ALT) and aspartate transaminase (AST) were evaluated. Levels of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), and DCFH-DA staining were used to evaluate the oxidative injury. Western blot and real-time PCR were applied to evaluate the expressions of proteins and mRNA. MTT was used to evaluate DOX-induced cell injury and the protective effects of PTS. Recombinant Trx-1 was used to analyze the mechanism of PTS. A TUNEL assay was used to detect apoptosis in DOX-induced HepG2 cells and the protective effects of PTS.

Results: PTS ameliorated DOX-induced liver pathological changes and the levels of AST and ALT. PTS also decreased the level of MDA, increased the level of SOD, GSH, and the expression of Trx-1 in DOX-treated mice. PTS decreased the levels of NLRP3 and IL-1β mRNA and the expressions of their proteins in DOX-treated mice. In addition, PTS also decreased the expression of Cleaved Caspase-3 and BAX and increased the expression of BCL-2. In vitro, after treatment with recombinant Trx-1, ROS and NLRP3 inflammasome were both decreased. Treatment with PTS could rescue the downregulation of Trx-1, decreased the ROS level and the NLRP3 inflammasome, and protected HepG2 cells against DOX-induced apoptosis.

Conclusion: The results show that PTS exhibits protective effects against DOX-induced liver injuries via suppression of oxidative stress, fibrosis, NLRP3 inflammasome stimulation, and cell apoptosis which might lead to a new approach of preventing DOX-induced hepatotoxicity.

An Overview of the TRP-Oxidative Stress Axis in Metabolic Syndrome: Insights for Novel Therapeutic Approaches

Metabolic syndrome (MS) is a complex pathology characterized by visceral adiposity, insulin resistance, arterial hypertension, and dyslipidaemia. It has become a global epidemic associated with increased consumption of high-calorie, low-fibre food and sedentary habits. Some of its underlying mechanisms have been identified, with hypoadiponectinemia, inflammation and oxidative stress as important factors for MS establishment and progression. Alterations in adipokine levels may favour glucotoxicity and lipotoxicity which, in turn, contribute to inflammation and cellular stress responses within the adipose, pancreatic and liver tissues, in addition to hepatic steatosis. The multiple mechanisms of MS make its clinical management difficult, involving both non-pharmacological and pharmacological interventions. Transient receptor potential (TRP) channels are non-selective calcium channels involved in a plethora of physiological events, including energy balance, inflammation and oxidative stress. Evidence from animal models of disease has contributed to identify their specific contributions to MS and may help to tailor clinical trials for the disease. In this context, the oxidative stress sensors TRPV1, TRPA1 and TRPC5, play major roles in regulating inflammatory responses, thermogenesis and energy expenditure. Here, the interplay between these TRP channels and oxidative stress in MS is discussed in the light of novel therapies to treat this syndrome.

The Secretome of Preconditioned Mesenchymal Stem Cells Drives Polarization and Reprogramming of M2a Macrophages toward an IL-10-Producing Phenotype

The preconditioning of mesenchymal stem cells (MSCs) has been recognized as an attractive tool to improve their regenerative and immunomodulatory capacities based on their paracrine effects. In this study, we examined the potential of an MSC-conditioned medium (MSC-CM) to alter the phenotype of murine macrophages and to drive reprogramming toward an anti-inflammatory, M2-like state in vitro. We further explored the impact of MSC cytokine preconditioning on the immunosuppressive properties of the MSC secretome. The MSC-CM suppressed the expression of proinflammatory genes in murine M1 macrophages, but only the CM from preconditioned MSCs (preMSC-CM) downregulated their expression during M1 polarization. Remarkably, only the preMSC-CM significantly increased the expression of M2a-, M2b- and M2c-specific genes and proteins during M2a polarization. Further, macrophages were found to secrete high levels of anti-inflammatory IL-10. Similarly, M2a macrophages cultured in the presence of the preMSC-CM displayed an enhanced expression of M2b/M2c-specific markers, suggesting that the secretome of preMSC promotes the repolarization of M2a-like macrophages to M2b/M2c subtypes. The preMSC-CM was found to be enriched in molecules involved in M2 polarization. Additionally, a unique downregulation of extracellular matrix components was observed. Altogether, the preMSC-CM may provide an attractive strategy to dampen inflammation by suppressing the expression of proinflammatory mediators and promoting the polarization and phenotype switch of M2a cells to IL-10-secreting M2b/M2c-like macrophages.

Immune Modulating Brevetoxins: Monocyte Cytotoxicity, Apoptosis, and Activation of M1/M2 Response Elements Is Dependent on Reactive Groups

Brevetoxins are a suite of marine neurotoxins that activate voltage-gated sodium channels (VGSCs) in cell membranes, with toxicity occurring from persistent activation of the channel at high doses. Lower doses, in contrast, have been shown to elicit neuroregeneration. Brevetoxins have thus been proposed as a novel treatment for patients after stroke, when neuron regrowth and repair is critical to recovery. However, findings from environmental exposures indicate that brevetoxins may cause inflammation, thus, there is concern for brevetoxins as a stroke therapy given the potential for neuroinflammation. In this study, we examined the inflammatory properties of several brevetoxin analogs, including those that do and do not bind strongly to VGSCs, as binding has classically indicated toxicity. We found that several analogs are toxic to monocytes, while others are not, and the degree of toxicity is not directly related to VGSC binding. Rather, results indicate that brevetoxins containing aldehyde groups were more likely to cause immunotoxicity, regardless of binding affinity to the VGSC. Our results demonstrate that different brevetoxin family members can elicit a spectrum of apoptosis and necrosis by multiple possible mechanisms of action in monocytes. As such, care should be taken in treating “brevetoxins” as a uniform group, particularly in stroke therapy research.

Long-Acting Thioredoxin Ameliorates Doxorubicin-Induced Cardiomyopathy via Its Anti-Oxidative and Anti-Inflammatory Action

Although the number of patients with heart failure is increasing, a sufficient treatment agent has not been established. Oxidative stress and inflammation play important roles in the development of myocardial remodeling. When thioredoxin (Trx), an endogenous anti-oxidative and inflammatory modulator with a molecular weight of 12 kDa, is exogenously administered, it disappears rapidly from the blood circulation. In this study, we prepared a long-acting Trx, by fusing human Trx (HSA-Trx) with human serum albumin (HSA) and evaluated its efficacy in treating drug-induced heart failure. Drug-induced cardiomyopathy was created by intraperitoneally administering doxorubicin (Dox) to mice three times per week. A decrease in heart weight, increased myocardial fibrosis and markers for myocardial damage that were observed in the Dox group were suppressed by HSA-Trx administration. HSA-Trx also suppressed the expression of atrogin-1 and myostatin, myocardial atrophy factors in addition to suppressing oxidative stress and inflammation. In the Dox group, a decreased expression of endogenous Trx in cardiac tissue and an increased expression of macrophage migration inhibitory factor were observed, but these changes were restored to normal levels by HSA-Trx administration. These findings suggest that HSA-Trx improves the pathological condition associated with Dox-induced cardiomyopathy by its anti-oxidative/anti-inflammatory and myocardial atrophy inhibitory action.

Ribosome profiling of porcine reproductive and respiratory syndrome virus reveals novel features of viral gene expression

The arterivirus porcine reproductive and respiratory syndrome virus (PRRSV) causes significant economic losses to the swine industry worldwide. Here we apply ribosome profiling (RiboSeq) and parallel RNA sequencing (RNASeq) to characterise the transcriptome and translatome of both species of PRRSV and to analyse the host response to infection. We calculated programmed ribosomal frameshift (PRF) efficiency at both sites on the viral genome. This revealed the nsp2 PRF site as the second known example where temporally regulated frameshifting occurs, with increasing -2 PRF efficiency likely facilitated by accumulation of the PRF-stimulatory viral protein, nsp1β. Surprisingly, we find that PRF efficiency at the canonical ORF1ab frameshift site also increases over time, in contradiction of the common assumption that RNA structure-directed frameshift sites operate at a fixed efficiency. This has potential implications for the numerous other viruses with canonical PRF sites. Furthermore, we discovered several highly translated additional viral ORFs, the translation of which may be facilitated by multiple novel viral transcripts. For example, we found a highly expressed 125-codon ORF overlapping nsp12, which is likely translated from novel subgenomic RNA transcripts that overlap the 3' end of ORF1b. Similar transcripts were discovered for both PRRSV-1 and PRRSV-2, suggesting a potential conserved mechanism for temporally regulating expression of the 3'-proximal region of ORF1b. We also identified a highly translated, short upstream ORF in the 5' UTR, the presence of which is highly conserved amongst PRRSV-2 isolates. These findings reveal hidden complexity in the gene expression programmes of these important nidoviruses.

Oxidative Stress and Cancer Heterogeneity Orchestrate NRF2 Roles Relevant for Therapy Response

Oxidative stress and its end-products, such as 4-hydroxynonenal (HNE), initiate activation of the Nuclear Factor Erythroid 2-Related Factor 2 (NRF2)/Kelch Like ECH Associated Protein 1 (KEAP1) signaling pathway that plays a crucial role in the maintenance of cellular redox homeostasis. However, an involvement of 4-HNE and NRF2 in processes associated with the initiation of cancer, its progression, and response to therapy includes numerous, highly complex events. They occur through interactions between cancer and stromal cells. These events are dependent on many cell-type specific features. They start with the extent of NRF2 binding to its cytoplasmic repressor, KEAP1, and extend to the permissiveness of chromatin for transcription of Antioxidant Response Element (ARE)-containing genes that are NRF2 targets. This review will explore epigenetic molecular mechanisms of NRF2 transcription through the specific molecular anatomy of its promoter. It will explain the role of NRF2 in cancer stem cells, with respect to cancer therapy resistance. Additionally, it also discusses NRF2 involvement at the cross-roads of communication between tumor associated inflammatory and stromal cells, which is also an important factor involved in the response to therapy.

Inflammation, Oxidative Stress, Senescence in Atherosclerosis: Thioredoxine-1 as an Emerging Therapeutic Target

Atherosclerosis is a leading cause of cardiovascular diseases (CVD) worldwide and intimately linked to aging. This pathology is characterized by chronic inflammation, oxidative stress, gradual accumulation of low-density lipoproteins (LDL) particles and fibrous elements in focal areas of large and medium arteries. These fibrofatty lesions in the artery wall become progressively unstable and thrombogenic leading to heart attack, stroke or other severe heart ischemic syndromes. Elevated blood levels of LDL are major triggering events for atherosclerosis. A cascade of molecular and cellular events results in the atherosclerotic plaque formation, evolution, and rupture. Moreover, the senescence of multiple cell types present in the vasculature were reported to contribute to atherosclerotic plaque progression and destabilization. Classical therapeutic interventions consist of lipid-lowering drugs, anti-inflammatory and life style dispositions. Moreover, targeting oxidative stress by developing innovative antioxidant agents or boosting antioxidant systems is also a well-established strategy. Accumulation of senescent cells (SC) is also another important feature of atherosclerosis and was detected in various models. Hence, targeting SCs appears as an emerging therapeutic option, since senolytic agents favorably disturb atherosclerotic plaques. In this review, we propose a survey of the impact of inflammation, oxidative stress, and senescence in atherosclerosis; and the emerging therapeutic options, including thioredoxin-based approaches such as anti-oxidant, anti-inflammatory, and anti-atherogenic strategy with promising potential of senomodulation.

Matrisome provides a supportive microenvironment for oral squamous cell carcinoma progression

Oral squamous cell carcinoma (OSCC) is a common pernicious tumor in the head and neck regions. However, the function of tumor extracellular matrix (ECM) has not been elucidated. A tissue engineering method was applied for remodeling ECM through decellularization. The cellular components were removed, and the biological composition was mostly preserved. Proteomics was performed to analyze the characterization between normal and tumor ECM. According to LC-MS/MS results, 26 proteins just showed in tumor ECM, and 14 proteins only showed in late-stage tumor ECM. KEGG pathway analysis showed that most variant proteins were linked to metabolic regulation and tumor immunity (such as SCC-Ag1, LOX). To affirm the influence of tumor ECM on the progression of OSCC, tumor cells and macrophages were co-cultured with ECM scaffold. Marked differences in proliferation, apoptosis, and migration of OSCC cells were observed between tumor and normal ECM. Tumor ECM polarized macrophages towards an anti-inflammatory phenotype (higher IL-10 and CD68, and relatively lower CD86 and IL1-β). Collectively, these findings suggest that tumor ECM served as a permissive role in OSCC progression. SIGNIFICANCE: The variation between OSCC ECM and normal ECM confirm tumor ECM plays a significant role in OSCC deterioration, which is conducive to exploring the occurrence and progression mechanisms of OSCC, and further improving the curative effect of this disease.

Amniotic fluid-derived extracellular vesicles: characterization and therapeutic efficacy in an experimental model of bronchopulmonary dysplasia

BACKGROUND AIMS

Extracellular vesicles (EVs) are being tested for their use as novel therapeutics. However, the optimal source of EVs is currently under investigation. Amniotic fluid (AF) is a natural source of EVs that can be easily obtained for use in regenerative medicine, yet AF-EV characterization has not been fully explored.

METHODS

Here the authors demonstrate AF as a rich source of EVs and identify the microRNA and proteomic cargo. Bioinformatics analysis of this cargo revealed multiple pathway targets, including immunomodulatory, anti-inflammatory and free radical scavenging networks. The authors further demonstrated the therapeutic potential of this EV product as a novel preventative agent for bronchopulmonary dysplasia (BPD).

RESULTS

Intra-tracheal administration of AF-EVs preserved alveolar development, attenuated vascular remodeling and pulmonary hypertension, decreased lung pro-inflammatory cytokine expression and reduced macrophage infiltration in an experimental BPD model.

CONCLUSIONS

The authors' results suggest that AF is a viable biological fluid for EV harvest and that AF-EVs have strong therapeutic potential for pulmonary diseases, such as BPD, warranting further development to transition this novel EV product into the clinic.

Innate and adaptive immunity: the understudied driving force of heart valve disease

Calcific aortic valve disease (CAVD), and its clinical manifestation that is calcific aortic valve stenosis, is the leading cause for valve disease within the developed world, with no current pharmacological treatment available to delay or halt its progression. Characterized by progressive fibrotic remodelling and subsequent pathogenic mineralization of the valve leaflets, valve disease affects 2.5% of the western population, thus highlighting the need for urgent intervention. Whilst the pathobiology of valve disease is complex, involving genetic factors, lipid infiltration, and oxidative damage, the immune system is now being accepted to play a crucial role in pathogenesis and disease continuation. No longer considered a passive degenerative disease, CAVD is understood to be an active inflammatory process, involving a multitude of pro-inflammatory mechanisms, with both the adaptive and the innate immune system underpinning these complex mechanisms. Within the valve, 15% of cells evolve from haemopoietic origin, and this number greatly expands following inflammation, as macrophages, T lymphocytes, B lymphocytes, and innate immune cells infiltrate the valve, promoting further inflammation. Whether chronic immune infiltration or pathogenic clonal expansion of immune cells within the valve or a combination of the two is responsible for disease progression, it is clear that greater understanding of the immune systems role in valve disease is required to inform future treatment strategies for control of CAVD development.

Filarial thioredoxin reductase exerts anti-inflammatory effects upon lipopolysaccharide induced inflammation in macrophages

Lymphatic filariasis and its associated health hazards have taken enormous tolls especially in the tropical and sub-tropical countries round the globe. Our present work contemplates the immunomodulatory role of filarial Thioredoxin reductase (TrxR) for the survival of the parasite inside the human host. For this, the protein TrxR was purified from the filarial parasite Setaria cervi and further substantiated through specific anti-TrxR antibody raised in mice. Both commercially available anti-TrxR antibody and laboratory raised antibody produced a single band with a molecular mass of ~80 kDa on western blot. The protein is optimally active at pH 7.0 and at temperature 37 °C. This protein contains both alpha helix and beta pleated sheet with selenocysteine at its active site. The Km was found to be 2.75 ± 0.49 mM. TrxR was found to downregulate lipopolysaccharide (LPS)-induced inflammation in macrophages due to inhibition of TLR4-NF-κB pathway. The result was further supported by the downregulation of inflammasome pathway and activation of alternatively activated macrophages upon TrxR treatment. Hence this study projects insights into the importance of filarial TrxR in host-parasite interface as well as it illustrates novel therapeutic strategy towards anti-filarial drug development.

New Horizons for the Roles and Association of APE1/Ref-1 and ABCA1 in Atherosclerosis

Atherosclerosis is the leading cause of death worldwide. APE1/Ref-1 and ABCA1 play key roles in the progression of atherosclerosis. APE1/Ref-1 suppresses atherosclerosis via multiple mechanisms, including reducing the IL-6-, TNF-α-, and IL-1β-mediated proinflammatory responses, suppressing ROS-mediated oxidant activity and Bax/Bcl-2-mediated vascular calcification and apoptosis, and reducing LOX-1-mediated cholesterol uptake. However, APE1/Ref-1 also promotes atherosclerosis by increasing the activity of the NK-κB and S1PR1 pathways. APE1/Ref-1 localizes to the nucleus, cytoplasm, and mitochondria and can be secreted from the cell. APE1/Ref-1 localization is dynamically regulated by the disease state and may be responsible for its proatherogenic and antiatherogenic effects. ABCA1 promotes cholesterol efflux and anti-inflammatory responses by binding to apoA-I and regulates apoptotic cell clearance and HSPC proliferation to protect against inflammatory responses. Interestingly, in addition to mediating these functions, ABCA1 promotes the secretion of acetylated APE1/Ref-1 (AcAPE1/Ref-1), a therapeutic target, which protects against atherosclerosis development. The APE1/Ref-1 inhibitor APX3330 is being evaluated in a phase II clinical trial. The LXR agonist LXR-623 (WAY-252623) is an agonist of ABCA1 and the first LXR-targeting compound to be evaluated in clinical trials. In this article, we review the roles of ABCA1 and APE1/Ref-1 in atherosclerosis and focus on new insights into the ABCA1-APE1/Ref-1 axis and its potential as a novel therapeutic target in atherosclerosis.

Understanding the role of S-nitrosylation/nitrosative stress in inflammation and the role of cellular denitrosylases in inflammation modulation: Implications in health and diseases

S-nitrosylation is a very fundamental post-translational modification of protein and non-protein thiols due the involvement of it in a variety of cellular processes including activation/inhibition of several ion channels such as ryanodine receptor in the cardiovascular system; blood vessel dilation; cGMP signaling and neurotransmission. S-nitrosothiol homeostasis in the cell is tightly regulated and perturbations in homeostasis result in an altered redox state leading to a plethora of disease conditions. However, the exact role of S-nitrosylated proteins and nitrosative stress metabolites in inflammation and in inflammation modulation is not well-reviewed. The cell utilizes its intricate defense mechanisms i.e. cellular denitrosylases such as Thioredoxin (Trx) and S-nitrosoglutathione reductase (GSNOR) systems to combat nitric oxide (NO) pathology which has also gained current attraction as novel anti-inflammatory molecules. This review attempts to provide state-of-the-art knowledge from past and present research on the mechanistic role of nitrosative stress intermediates (RNS, OONO^-, PSNO) in pulmonary and autoimmune diseases and how cellular denitrosylases particularly GSNOR and Trx via imparting opposing effects can modulate and reduce inflammation in several health and disease conditions. This review would also bring into notice the existing gaps in current research where denitrosylases can be utilized for ameliorating inflammation that would leave avenues for future therapeutic interventions.

Thioredoxin-1 and Correlations of the Plasma Cytokines Regarding Aortic Valve Stenosis Severity

Aortic valve stenosis (AS) develops not only with a pronounced local inflammatory response, but also oxidative stress is involved. The aim of this study was to evaluate the plasma levels of thioredoxin-1 (TRX1), myeloperoxidase (MPO), chemerin, growth differentiation factor 15 (GDF-15), angiopoietin-2 (Ang-2), vascular endothelial growth factor A (VEGF-A), fibroblast growth factor 2 (FGF-2), fibroblast growth factor 21 (FGF-21), and metalloproteinase (MMP)-1, -3, and -9 in acquired AS patients as well as to clarify the correlations of TXR1 and the plasma inflammatory biomarkers regarding AS severity. AS patients were classified into three groups: 16 patients with mild AS stenosis, 19 with moderate and 11 with severe AS, and 30 subjects without AS were selected as a control group. AS patients had significantly higher plasma levels of TRX1 compared to controls, but the highest difference was found in mild AS patients compared to the controls. We conclude that AS is associated with significantly increased plasma TRX1 levels, and TRX1 might serve as a specific and sensitive biomarker of AS. TRX1 and also chemerin, GDF-15, VEGF-A, FGF-2 and FGF-21 significantly correlate with AS severity degrees. TRX1 also showed positive association with FGF-2, VEGF-A, and MMP-3 in all AS patients.

Chemerin in atherosclerosis

Atherosclerosis (AS), a chronic arterial disease, is characterized by endothelial dysfunction, inflammatory reactions and lipid accumulation in parallel with aberrant angiogenesis and vascular smooth muscle cell (VSMC) proliferation. Adipose tissue has been suggested to have an integral influence on metabolism and endocrine secretion, while there have been increasing concerns about the possible involvement of adipokines in cardiovascular diseases, including AS. Here, we focused on chemerin, an adipokine highly expressed in adipose tissue, with strong evidence of an association with inflammation, endothelial dysfunction, metabolic disorder, aberrant angiogenesis, VSMC proliferation and calcification. In this review, we discuss chemerin and its receptors in the pathogenesis of AS. However, the existing data assign various, even contradictory, roles to chemerin in atherosclerosis, such as inhibiting vascular calcification and impairing endothelial function. Current studies focusing on its anti- and pro-atherogenic effects have pinpointed its distinct role in specific cell types and contexts in the pathogenesis of atherosclerosis. Therefore, the gaps in current knowledge regarding the specific role played by chemerin in the etiology of AS require additional future studies. It seems reasonable to suggest that targeted chemerin therapy can be developed as an innovative approach for treating AS.

Natural Molecules Targeting Thioredoxin System and Their Therapeutic Potential

Significance: Thioredoxin (Trx) and thioredoxin reductase are two core members of the Trx system. The system bridges the gap between the universal reducing equivalent NADPH and various biological molecules and plays an essential role in maintaining cellular redox homeostasis and regulating multiple cellular redox signaling pathways. Recent Advance: In recent years, the Trx system has been well documented as an important regulator of many diseases, especially tumorigenesis. Thus, the development of potential therapeutic molecules targeting the system is of great significance for disease treatment. Critical Issues: We herein first discuss the physiological functions of the Trx system and the role that the Trx system plays in various diseases. Then, we focus on the introduction of natural small molecules with potential therapeutic applications, especially the anticancer activity, and review their mechanisms of pharmacological actions via interfering with the Trx system. Finally, we further discuss several natural molecules that harbor therapeutic potential and have entered different clinical trials. Future Directions: Further studies on the functions of the Trx system in multiple diseases will not only improve our understanding of the pathogenesis of many human disorders but also help develop novel therapeutic strategies against these diseases. Antioxid. Redox Signal. 34, 1083-1107.

Imbalance in thioredoxin system activates NLRP3 inflammasome pathway in epicardial adipose tissue of patients with coronary artery disease

Atherosclerosis is the leading cause of death worldwide and has in part an inflammatory basis. Since epicardial adipose tissue (EAT) is in close contact with coronary arteries we hypothesized that an imbalance in thioredoxin-1 (TRX-1) and thioredoxin interacting protein (TXNIP) in EAT, activates NLRP3 inflammasome and promotes production of IL-1β, leading to the development of atherosclerosis. Thirty-eight patients with coronary artery disease (CAD) and thirty patients with no clinical signs of atherosclerosis who underwent open-heart surgery for valve replacement were classified as CAD and control groups, respectively. Biopsy samples from EAT were collected and expression of TXNIP, TRX-1, NLRP3 and IL-1β genes were assessed using qRT-PCR. Tissue protein levels of TXNIP and TRX-1 were determined by Western blotting while ELISA was applied to measure IL-1β. Haematoxylin and eosin staining was used for histological examination. mRNA and protein levels of TXNIP in EAT were significantly higher in patients with CAD compared with control group, whereas CAD patients showed lower TRX-1 gene and protein expression. In addition, in CAD patients the NLRP3 gene expression was almost doubled and IL-1β significantly increased at the both mRNA and protein levels. Enhancment in NLRP3 gene expression and TXNIP protein levels were accompanied with the increase in IL-1β protein level whereas TRX-1 protein content showed a negative correlation with IL-1β level. Concurrent increase in TXNIP, NLRP3, and IL-1β suggests possible involvement of thioredoxin system in the activation of NLRP3 inflammasome, production of IL-1β, and the presence of inflammation in CAD patients.

Up-regulation of thioredoxin system by puerarin inhibits lipid uptake in macrophages

Cellular oxidative stress promotes lipid accumulation in macrophages during atherogenesis. Puerarin is a natural isoflavone with beneficial effects against oxidation and atherosclerosis. In this study, we investigated the effects of puerarin on lipid uptake and explored the underlying molecular regulation. We found puerarin up-regulated thioredoxin-1 (Trx1) and Trx reductase-1 (TrxR1) expression; it increased TrxR1 activity, cellular thiols contents and decreased oxidized form of Trx1, thus inhibiting cellular ROS generation. Confocal microscope and flow cytometry analysis showed fluorescence labeled Dil-oxLDL uptake was dramatically inhibited by puerarin in RAW264.7 cells as well as in primary bone marrow derived macrophages and peritoneal macrophages. The effects were reversed when Trx1 was inhibited by treatment with Trx1 inhibitor PX-12 or Trx1 siRNA. We also found scavenger receptors such as SR-A and Lox-1, but not CD36 were involved in the Trx1-mediated lipid uptake inhibition. Moreover, measurements of foam cell accumulation and ROS production in sections of aortic roots showed those were reduced by puerarin but raised when additional treatment with PX-12 or Trx1 siRNA in apoE-/- mice, which demonstrates the lipid uptake reduction by puerarin requires Trx1 inhibition in vivo. In addition, we analyzed the upstream regulation and found puerarin induced Nrf2 activity; cooperation between Nrf2 and ATF4 facilitated the puerarin effects. PERK phosphorylation was detected to be increased by puerarin, while PERK inhibition reduced cellular Trx1, TrxR1, nuclear Nrf2 and ATF4. Altogether, puerarin modulates PERK/Nrf2 that coordinates with ATF4 to active Trx1, which causes SR-A and Lox-1 reduction and lipid uptake inhibition in macrophages. This suggests Trx1 could be an effective target by puerarin in the prevention of atherosclerosis.

Cutting Edge: NOX2 NADPH Oxidase Controls Infection by an Intracellular Bacterial Pathogen through Limiting the Type 1 IFN Response

The NOX2 NADPH oxidase (NOX2) produces reactive oxygen species to kill phagosome-confined bacteria. However, we previously showed that Listeria monocytogenes is able to avoid the NOX2 activity in phagosomes and escape to the cytosol. Thus, despite the established role of NOX2 limiting L. monocytogenes infection in mice, the underlying mechanisms of this antibacterial activity remain unclear. In this article, we report that NOX2 controls systemic L. monocytogenes spread through modulation of the type I IFN response, which is known to be exploited by L. monocytogenes during infection. NOX2 deficiency results in increased expression of IFN-stimulated genes in response to type I IFN and leads to 1) promotion of cell-to-cell spread by L. monocytogenes, 2) defective leukocyte recruitment to infection foci, and 3) production of anti-inflammatory effectors IL-10 and thioredoxin 1. Our findings report a novel antimicrobial role for NOX2 through modulation of type I IFN responses to control bacterial dissemination.

Protein expression profile of Taenia crassiceps cysticerci related to Th1- and Th2-type responses in the mouse cysticercosis model

The intraperitoneal cysticercosis model with the Taenia crassiceps ORF strain in female BALB/cAnN mice has been widely used to study the immune response in cysticercosis. During early infection (2 weeks), the host develops a non-permissive Th1 response, whereas during late infection (8 weeks), molecules from the cysticerci induce a Th2 response that is permissive to parasite growth. The modulation of the Th2 response is induced by molecules excreted/secreted by the larval stage of the parasite. However, there is limited information regarding the response of cysticerci to the mouse immunological environment during infection. The proteomic profiles in T. crassiceps ORF cysticerci when faced with the mouse Th1 and Th2 responses were analyzed through two-dimensional gel electrophoresis (2DE), and the differential expression of proteins was evaluated. Thirteen proteins, whose differential expression varied between 70% and 100%, were selected randomly. Protein identification by MALDI-TOF MS and BLAST showed that the proteins were related to folding, signaling, enzymatic activities, cell-movement regulation, cell-cell interactions, motility, carbohydrate metabolism, detoxification, and redox regulation processes. Notably, some of the proteins can act as antigenic-protective molecules and elicit a weak Th1 response; however, most are involved in the avoidance of the immune system, which leads to a Th2 response, or apoptosis. The findings indicate the process by which T. crassiceps cysticerci responds based on the host environment and provides novel insights into the mechanism by which this facilitates its establishment and persistence in the mouse. Furthermore, these proteins could be used as targets for drug and vaccine development.

Good Cop, Bad Cop: The Opposing Effects of Macrophage Activation State on Maintaining or Damaging Functional β-Cell Mass

Loss of functional β-cell mass is a hallmark of Type 1 and Type 2 Diabetes. Macrophages play an integral role in the maintenance or destruction of pancreatic β-cells. The effect of the macrophage β-cell interaction is dependent on the activation state of the macrophage. Macrophages can be activated across a spectrum, from pro-inflammatory to anti-inflammatory and tissue remodeling. The factors secreted by these differentially activated macrophages and their effect on β-cells define the effect on functional β-cell mass. In this review, the spectrum of macrophage activation is discussed, as are the positive and negative effects on β-cell survival, expansion, and function as well as the defined factors released from macrophages that impinge on functional β-cell mass.

ADAM17 cytoplasmic domain modulates Thioredoxin-1 conformation and activity

The activity of Thioredoxin-1 (Trx-1) is adjusted by the balance of its monomeric, active and its dimeric, inactive state. The regulation of this balance is not completely understood. We have previously shown that the cytoplasmic domain of the transmembrane protein A Disintegrin And Metalloprotease 17 (ADAM17cyto) binds to Thioredoxin-1 (Trx-1) and the destabilization of this interaction favors the dimeric state of Trx-1. Here, we investigate whether ADAM17 plays a role in the conformation and activation of Trx-1. We found that disrupting the interacting interface with Trx-1 by a site-directed mutagenesis in ADAM17 (ADAM17cyto^F730A) caused a decrease of Trx-1 reductive capacity and activity. Moreover, we observed that ADAM17 overexpressing cells favor the monomeric state of Trx-1 while knockdown cells do not. As a result, there is a decrease of cell oxidant levels and ADAM17 sheddase activity and an increase in the reduced cysteine-containing peptides in intracellular proteins in ADAM17cyto overexpressing cells. A mechanistic explanation that ADAM17cyto favors the monomeric, active state of Trx-1 is the formation of a disulfide bond between Cys⁸²⁴ at the C-terminal of ADAM17cyto with the Cys⁷³ of Trx-1, which is involved in the dimerization site of Trx-1. In summary, we propose that ADAM17 is able to modulate Trx-1 conformation affecting its activity and intracellular redox state, bringing up a novel possibility for positive regulation of thiol isomerase activity in the cell by mammalian metalloproteinases.

Thioredoxin-1 attenuates atherosclerosis development through inhibiting NLRP3 inflammasome

BACKGROUNDS

The thioredoxin-1 has atheroprotective effects via regulating oxidative stress and inflammation. In addition, the NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome also contributes to atherosclerosis development. However, whether the thioredoxin-1 suppresses atherosclerosis development by modulating the NLRP3 inflammasome remains unclear.

METHODS

The regulation of NLRP3 inflammasome by thioredoxin-1 was determined in vitro on macrophage cells after ox-LDL (oxidized low-density lipoprotein) stimulation. The IL-1β and caspase-1 p10 secretion were assessed by ELISA and western blot. Finally, the thioredoxin-1/NLRP3 inflammasome pathway was confirmed in apolipoprotein E-deficient mice.

RESULTS

Thioredoxin-1 suppressed the expression of NLRP3, the secretion of IL-1β and caspase-1 p10 in vitro. And ROS stimulation activated the NLRP3 inflammasome which was inhibited by thioredoxin-1. In the mouse model of atherosclerosis, thioredoxin-1 delivered by lentivirus vector inhibited atherosclerosis development. And the atheroprotective effects of thioredoxin-1 were attenuated by ROS stimulation. Furthermore, the regulation of NLRP3 inflammasome by thioredoxin-1 was also confirmed in vivo.

CONCLUSIONS

We demonstrated here that the thioredoxin-1 had atheroprotective functions through thioredoxin-1/NLRP3 inflammasome pathway.

Melatonin induced suppression of ER stress and mitochondrial dysfunction inhibited NLRP3 inflammasome activation in COPD mice

In recent decades, the occurrence of chronic obstructive pulmonary disease (COPD) has been increased remarkably in the population. Cigarette smoke (Cs) plays one of the key roles for COPD development. In our study, we explored the ameliorative role of melatonin on COPD progression by using a Cs inhaled in vivo COPD and cigarette smoke extract (CSE)-treated in vitro L-132 (alveolar epithelial cell) models. Mice exposed to Cs (4hr/day for 4 weeks) exhibited abrupt increase of lactate dehydrogenase (LDH) level in broncho alveolar lavage fluid (BALF) and disrupted alveolar structure in lung tissue. Additionally, increased reactive oxygen species (ROS), decreased cellular antioxidant status with reduced GSH/GSSG ratio were also found in Cs exposed lung. Besides, Cs induced endoplasmic reticulum (ER) stress and mitochondrial dysfunctions causing the activation of NLRP3 inflammasome. Activated NLRP3 inflammasome caused Caspase-1 mediated release of IL-1β and IL-18 resulting in inflammatory outburst. Melatonin showed protection against COPD both in vitro and in vivo. Exhibiting its anti-inflammatory potential, melatonin also attenuated the lung inflammation. It activated the intracellular antioxidant Thioredoxin-1 (thereby suppressing the TXNIP/NLRP3 pathway) and inhibited the impaired mitophagy mediated inflammasome activation (upregulating PINK-1, Parkin, LC3B-II expression). Melatonin also improved the overall antioxidant status of the COPD lung via NRF-2-HO-1 axis restoration.

Integrated omics profiling of dextran sodium sulfate-induced colitic mice supplemented with Wolfberry (Lycium barbarum)

We used a multi-omics profiling approach to investigate the suppressive effects of 2% Wolfberry (WOL)-enriched diets on dextran sodium sulfate (DSS)-induced colitis in mice. It was observed that in mice fed the WOL diet, the disease activity index, colon shortening, plasma concentrations of matrix metalloproteinase-3 and relative mesenteric fat weight were significantly improved as compared to the DSS group. Results from colon transcriptome and proteome profiles showed that WOL supplementation significantly ameliorated the expression of genes and proteins associated with the integrity of the colonic mucosal wall and colonic inflammation. Based on the hepatic transcriptome, proteome and metabolome data, genes involved in fatty acid metabolism, proteins involved in inflammation and metabolites related to glycolysis were downregulated in WOL mice, leading to lowered inflammation and changes in these molecules may have led to improvement in body weight loss. The integrated nutrigenomic approach thus revealed the molecular mechanisms underlying the ameliorative effect of whole WOL fruit consumption on inflammatory bowel disease.

Role of reactive oxygen species in atherosclerosis: Lessons from murine genetic models

Atherosclerosis is a multifactorial chronic and inflammatory disease of medium and large arteries, and the major cause of cardiovascular morbidity and mortality worldwide. The pathogenesis of atherosclerosis involves a number of risk factors and complex events including hypercholesterolemia, endothelial dysfunction, increased permeability to low density lipoproteins (LDL) and their sequestration on extracellular matrix in the intima of lesion-prone areas. These events promote LDL modifications, particularly by oxidation, which generates acute and chronic inflammatory responses implicated in atherogenesis and lesion progression. Reactive oxygen species (ROS) (which include both free radical and non-free radical oxygen intermediates), play a key-role at each step of atherogenesis, in endothelial dysfunction, LDL oxidation, and inflammatory events involved in the initiation and development of atherosclerosis lesions. Most advanced knowledge supporting the "oxidative theory of atherosclerosis" i.e. the nature and the cellular sources of ROS and antioxidant defences, as well as the mechanisms involved in the redox balance, is based on the use of genetically engineered animals, i.e. transgenic, genetically modified, or altered for systems producing or neutralizing ROS in the vessels. This review summarizes the results obtained from animals genetically manipulated for various sources of ROS or antioxidant defences in the vascular wall, and their relevance (advance or limitation), for understanding the place and role of ROS in atherosclerosis.

Different monocyte phenotypes result in proresolving macrophages in conjugated linoleic acid-induced attenuated progression and regression of atherosclerosis

Monocytes/macrophages drive progression and regression of atherosclerosis. Conjugated linoleic acid (CLA), an anti-inflammatory lipid, mediates atheroprotective effects. We investigated how CLA alters monocyte/macrophage phenotype during attenuated progression and regression of atherosclerosis. Apolipoprotein E knockout (ApoE^-/-) mice were fed a high-fat (60%) high-cholesterol (1%) diet (HFHCD) for 2 wk, followed by 6-wk 1% CLA 80:20 supplementation to investigate disease progression. Simultaneously, ApoE^-/- mice were fed a 12-wk HFHCD with/without CLA for the final 4 wk to investigate regression. Aortic lesions were quantified by en face staining. Proteomic analysis, real-time quantitative PCR and flow cytometry were used to interrogate monocyte/macrophage phenotypes. CLA supplementation inhibited atherosclerosis progression coincident with decreased proinflammatory and increased anti-inflammatory macrophages. However, CLA-induced regression was associated with increased proinflammatory monocytes resulting in increased proresolving M2 bone marrow-derived macrophages, splenic macrophages, and dendritic cells in lesion-draining lymph nodes. Proteomic analysis confirmed regulation of a proinflammatory bone marrow response, which was abolished upon macrophage differentiation. Thus, in attenuation and regression of atherosclerosis, regardless of the monocyte signature, during monocyte to macrophage differentiation, proresolving macrophages prevail, mediating vascular repair. This study provides novel mechanistic insight into the monocyte/macrophage phenotypes in halted atherosclerosis progression and regression of atherosclerosis.-Bruen, R., Curley, S., Kajani, S., Lynch, G., O'Reilly, M. E., Dillon, E. T., Fitzsimons, S., Mthunzi, L., McGillicuddy, F. C., Belton, O. Different monocyte phenotypes result in proresolving macrophages in conjugated linoleic acid-induced attenuated progression and regression of atherosclerosis.

Thioredoxin-1 promotes macrophage reverse cholesterol transport and protects liver from steatosis

Atherosclerosis is characterized by the accumulation of excess cholesterol in plaques. Reverse cholesterol transport (RCT) plays a key role in the removal of cholesterol. In the present study, we examined the effect of thioredoxin-1 (Trx-1) on RCT and explored the underlying mechanism. We found that Trx-1 promoted RCT in vivo, as did T0901317, a known liver X receptor (LXR) ligand. T0901317 also inhibited the development of atherosclerotic plaques but promoted liver steatosis. Furthermore, Trx-1 promoted macrophage cholesterol efflux to apoAI in vitro. Mechanistically, Trx-1 promoted nuclear translocation of LXRα and induced the expression of ATP-binding cassette transporter A1 (ABCA1). Apolipoprotein E knockout (apoE-/-) mice fed an atherogenic diet were daily injected intraperitoneally with saline or Trx-1 (0.33 mg/kg). Trx-1 treatment significantly inhibited the development of atherosclerosis and induced the expression of ABCA1 in macrophages retrieved from apoE-/- mice. Moreover, the liver steatosis was attenuated by Trx-1. Overall, we demonstrated that Trx-1 promotes RCT by upregulating ABCA1 expression through induction of nuclear translocation of LXRα, and protects liver from steatosis.

Extracellular vesicle-mediated macrophage activation: An insight into the mechanism of thioredoxin-mediated immune activation

Extracellular vesicles (EVs) generated from redox active anticancer drugs are released into the extracellular environment. These EVs contain oxidized molecules and trigger inflammatory responses by macrophages. Using a mouse model of doxorubicin (DOX)-induced tissue injury, we previously found that the major sources of circulating EVs are from heart and liver, organs that are differentially affected by DOX. Here, we investigated the effects of EVs from cardiomyocytes and those from hepatocytes on macrophage activation. EVs from H9c2 rat cardiomyocytes (H9c2 EVs) and EVs from FL83b mouse hepatocytes (FL83 b EVs) have different levels of protein-bound 4-hydroxynonenal and thus different immunostimulatory effects on mouse RAW264.7 macrophages. H9c2 EVs but not FL83 b EVs induced both pro-inflammatory and anti-inflammatory macrophage activation, mediated by NFκB and Nrf-2 pathways, respectively. DOX enhanced the effects of H9c2 EVs but not FL83 b EVs. While EVs from DOX-treated H9c2 cells (H9c2 DOXEVs) suppressed mitochondrial respiration and increased glycolysis of macrophages, EVs from DOX-treated FL83b cells (FL83b DOXEVs) enhanced mitochondrial reserve capacity. Mechanistically, the different immunostimulatory functions of H9c2 EVs and FL83 b EVs are regulated, in part, by the redox status of the cytoplasmic thioredoxin 1 (Trx1) of macrophages. H9c2 DOXEVs lowered the level of reduced Trx1 in cytoplasm while FL83b DOXEVs did the opposite. Trx1 overexpression alleviated the effect of H9c2 DOXEVs on NFκB and Nrf-2 activation and prevented the upregulation of their target genes. Our findings identify EVs as a novel Trx1-mediated redox mediator of immune response, which greatly enhances our understanding of innate immune responses during cancer therapy.

Thioredoxin-1 confines T cell alloresponse and pathogenicity in graft-versus-host disease

Oxidative stress is elevated in the recipients of allogeneic hematopoietic transplantation (allo-HCT) and likely contributes to the development of graft-versus-host disease (GVHD). GVHD is characterized by activation, expansion, cytokine production and migration of alloreactive donor T cells, and remains a major cause of morbidity and mortality after allo-HCT. Hence, strategies to limit oxidative stress in GVHD are highly desirable. Thioredoxin1 (Trx1) counteracts oxidative stress by scavenging reactive oxygen species (ROS) and regulating other enzymes that metabolize H2O2. The present study sought to elucidate the role of Trx1 in the pathophysiology of GVHD. Using murine and xenograft models of allogeneic bone marrow transplantation (allo-BMT) and genetic (human Trx1-transgenic, Trx1-Tg) as well as pharmacologic (human recombinant Trx1, RTrx1) strategies; we found that Trx1-Tg donor T cells or administration of the recipients with RTrx1 significantly reduced GVHD severity. Mechanistically, we observed RTrx1 reduced ROS accumulation and cytokine production of mouse and human T cells in response to alloantigen stimulation in vitro. In allo-BMT settings, we found that Trx1-Tg or RTrx1 decreased downstream signaling molecules including NFκB activation and T-bet expression, and reduced proliferation, IFN-γ production and ROS accumulation in donor T cells within GVHD target organs. More importantly, administration of RTrx1 did not impair the graft-versus-leukemia (GVL) effect. Taken together, the current work provides a strong rationale and demonstrates feasibility to target the ROS pathway, which can be readily translated into clinic.

M2 Macrophages as a Potential Target for Antiatherosclerosis Treatment

Atherosclerosis is a chronic progressive inflammation course, which could induce life-threatening diseases such as stroke and myocardial infarction. Optimal medical treatments for atherosclerotic risk factors with current antihypertensive and lipid-lowering drugs (for example, statins) are widely used in clinical practice. However, many patients with established disease still continue to have recurrent cardiovascular events in spite of treatment with a state-of-the-art therapy. Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of mortality worldwide. Hence, current treatment of atherosclerosis is still far from being satisfactory. Recently, M2 macrophages have been found associated with atherosclerosis regression. The M2 phenotype can secrete anti-inflammatory factors such as IL-10 and TGF-β, promote tissue remodeling and repairing through collagen formation, and clear dying cells and debris by efferocytosis. Therefore, modulators targeting macrophages' polarization to the M2 phenotype could be another promising treatment strategy for atherosclerosis. Two main signaling pathways, the Akt/mTORC/LXR pathway and the JAK/STAT6 pathway, are found playing important roles in M2 polarization. In addition, researchers have reported several potential approaches to modulate M2 polarization. Inhibiting or activating some kinds of enzymes, affecting transcription factors, or acting on several membrane receptors could regulate the polarization of the M2 phenotype. Besides, biomolecules, for example vitamin D, were found to affect the process of M2 polarization. Pomegranate juice could promote M2 polarization via unclear mechanism. In this review, we will discuss how M2 macrophages affect atherosclerosis regression, signal transduction in M2 polarization, and outline potential targets and compounds that affect M2 polarization, thus controlling the progress of atherosclerosis.

Redox-Sensitive Innate Immune Pathways During Macrophage Activation in Type 1 Diabetes

SIGNIFICANCE

Type 1 diabetes (T1D) is an autoimmune disease resulting in β-cell destruction mediated by islet-infiltrating leukocytes. The role of oxidative stress in human and murine models of T1D is highly significant as these noxious molecules contribute to diabetic complications and β-cell lysis, but their direct impact on dysregulated autoimmune responses is highly understudied. Pro-inflammatory macrophages play a vital role in the initiation and effector phases of T1D by producing free radicals and pro-inflammatory cytokines to facilitate β-cell destruction and to present antigen to autoreactive T cells. Recent Advances: Redox modulation of macrophage functions may play critical roles in autoimmunity. These include enhancing pro-inflammatory innate immune signaling pathways in response to environmental triggers, enforcing an M1 macrophage differentiation program, controlling antigen processing, and altering peptide recognition by oxidative post-translational modification. Therefore, an oxidative environment may act on multiple macrophage functions to orchestrate T1D pathogenesis.

CRITICAL ISSUES

Mechanisms involved in the initiation of T1D remain unclear, making preventive and early therapeutics difficult to develop. Although many of these advances in the redox regulation of macrophages are in their infancy, they provide insight into how oxidative stress aids in the precipitating event of autoimmune activation.

FUTURE DIRECTIONS

Future studies should be aimed at mechanistically determining which redox-regulated macrophage functions are pertinent in T1D pathogenesis, as well as at investigating potential targetable therapeutics to halt and/or dampen innate immune activation in T1D.

The proinflammatory effects of macrophage-derived NADPH oxidase function in autoimmune diabetes

Type 1 diabetes (T1D) is an autoimmune disease culminating in the destruction of insulin-producing pancreatic β-cells. While ultimately a T cell-mediated disease, macrophages play an indispensable role in disease initiation and progression. Infiltrating macrophages generate an inflammatory environment by releasing NADPH oxidase-derived superoxide and proinflammatory cytokines. The synthesis of reactive oxygen species (ROS) is acknowledged as putative factors contributing to autoimmunity and β-cell damage in T1D. In addition to direct lysis, free radicals collectively participate in β-cell destruction by providing a redox-dependent third signal necessary for islet-reactive CD4 and CD8 T cell maturation and by inducing oxidative post-translational modifications of β-cell epitopes to further exacerbate autoimmune responses. This review will provide an overview of macrophage function and a synergistic cross-talk with redox biology that contributes to autoimmune dysregulation in T1D.

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

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