Redox regulation of tumor necrosis factor signaling

A preliminary study of combined toxicity and underlying mechanisms of imidacloprid and cadmium coexposure using a multiomics integration approach

Imidacloprid (IMI) and cadmium (Cd) have been shown to be harmful to mammals separately, but their combined toxicity to mammals remains largely unknown. In this study, biochemical analysis (oxidative stress and serum indicators of liver and kidney function), pathological sections and multiomics (metabolomics and transcriptomics) methods were used to investigate the changes and mechanisms of liver and kidney in mice coexposed to IMI and Cd. Biochemical analysis and pathological section results showed that oxidative stress, organ function, and cell damage were aggravated after the combination of the two methods. Omics results revealed the following mechanism: When mouse liver and kidney cells were threatened by the external environment, mitochondrial DNA was inhibited, which leads to changes in energy metabolism. In this process, lipid metabolism and amino acid metabolism were disordered, resulting in the inhibition of substances related to lipid metabolism and amino acid metabolism that protect the body from oxidative damage, and then showed more serious liver and kidney oxidative stress and liver and kidney function and cell damage. This research offers novel insights for the assessment of the safety profile associated with the concurrent exposure of the two chemicals in mammalian species.

Investigating the relationship of co-exposure to multiple metals with chronic kidney disease: An integrated perspective from epidemiology and adverse outcome pathways

Systematic studies on the associations between co-exposure to multiple metals and chronic kidney disease (CKD), as well as the underlying mechanisms, remain insufficient. This study aimed to provide a comprehensive perspective on the risk of CKD induced by multiple metal co-exposures through the integration of occupational epidemiology and adverse outcome pathway (AOP). The study participants included 401 male mine workers whose blood metal, β2-microglobulin (β2-MG), and cystatin C (Cys-C) levels were measured. Generalized linear models (GLMs), quantile g-computation models (qgcomp), least absolute shrinkage and selection operator (LASSO), and bayesian kernel machine regression (BKMR) were utilized to identify critical nephrotoxic metals. The mean concentrations of lead, cadmium, mercury, arsenic, and manganese were 191.93, 3.92, 4.66, 3.11, 11.35, and 16.33 µg/L, respectively. GLM, LASSO, qgcomp, and BKMR models consistently identified lead, cadmium, mercury, and arsenic as the primary contributors to kidney toxicity. Based on our epidemiological analysis, we used a computational toxicology method to construct a chemical-genetic-phenotype-disease network (CGPDN) from the Comparative Toxicogenomics Database (CTD), DisGeNET, and GeneCard databases, and further linked key events (KEs) related to kidney toxicity from the AOP-Wiki and PubMed databases. Finally, an AOP framework of multiple metals was constructed by integrating the common molecular initiating events (reactive oxygen species) and KEs (MAPK signaling pathway, oxidative stress, mitochondrial dysfunction, DNA damage, inflammation, hypertension, cell death, and kidney toxicity). This is the first AOP network to elucidate the internal association between multiple metal co-exposures and CKD, providing a crucial basis for the risk assessment of multiple metal co-exposures.

Study on characterization of Bupleurum chinense polysaccharides with antioxidant mechanisms focus on ROS relative signaling pathways and anti-aging evaluation in vivo model

This study explored the structures of three polysaccharides from Bupleurum chinense DC. (BCPRs), and evaluated their antioxidant and anti-aging properties. The HPGPC and ion chromatography analyses revealed that the molecular weights of the BCPRs ranged from 12.05 to 21.20 kDa, and were primarily composed of rhamnose, arabinose, xylose, galactose, glucose and galacturonic acid. Methylation and NMR studies identified 10 PMAAs, establishing the various backbones of BCPRs 1-3. BCPR-3 demonstrated potent antioxidant activities, including DPPH, ABTS, hydroxy, and superoxide radicals scavenging in vitro. At concentrations between 125 and 500 μg/mL, BCPR-3 increased T-AOC, SOD and GSH-Px activities, while decreasing MDA levels in H2O2-induced SH-SY5Y cells. In addition, RNA-seq results indicated that BCPR-3 considerably downregulated the expression of 49 genes and upregulated five genes compared with the control group. KEGG analysis suggested that these differentially expressed genes (DEGs) were predominantly involved in the TNF and PI3K/Akt signaling pathways. Furthermore, in vivo experiment with Drosophila melanogaster showed that BCPR-3 could extend the average lifespan of flies. In conclusion, polysaccharides from B. chinense exhibited potential antioxidant and anti-aging activities, which could be developed as new ingredients to combat oxidative stress damage and slow the aging process.

Phosphorylated SARM1 is involved in the pathological process of rotenone-induced neurodegeneration

Sterile alpha and Toll/interleukin receptor motif-containing protein 1 (SARM1) is a NAD+ hydrolase that plays a key role in axonal degeneration and neuronal cell death. We reported that c-Jun N-terminal kinase (JNK) activates SARM1 through phosphorylation at Ser-548. The importance of SARM1 phosphorylation in the pathological process of Parkinson's disease (PD) has not been determined. We thus conducted the present study by using rotenone (an inducer of PD-like pathology) and neurons derived from induced pluripotent stem cells (iPSCs) from healthy donors and a patient with familial PD PARK2 (FPD2). The results showed that compared to the healthy neurons, FPD2 neurons were more vulnerable to rotenone-induced stress and had higher levels of SARM1 phosphorylation. Similar cellular events were obtained when we used PARK2-knockdown neurons derived from healthy donor iPSCs. These events in both types of PD-model neurons were suppressed in neurons treated with JNK inhibitors, Ca2+-signal inhibitors, or by a SARM1-knockdown procedure. The degenerative events were enhanced in neurons overexpressing wild-type SARM1 and conversely suppressed in neurons overexpressing the SARM1-S548A mutant. We also detected elevated SARM1 phosphorylation in the midbrain of PD-model mice. The results indicate that phosphorylated SARM1 plays an important role in the pathological process of rotenone-induced neurodegeneration.

Diet enriched in saturated fatty acids induces liver oxidative stress and elicits inflammatory pathways prior to metabolic disruption in perinatal protein undernutrition

The impact of diets high in saturated fatty acids in individuals who have undergone maternal protein restriction is not clear. Here, we tested the hypothesis that a saturated fatty acid-enriched hyperlipidic diet (HL) affects liver expression of genes of the redox balance and inflammatory pathway in postweaning rat offspring subjected to maternal protein restriction. Pregnant Wistar rats received either a control (C; 19% protein) or low protein (LP; 8% protein) diet during gestation and lactation. At weaning, pups received either C or HL diets up to 90 days of life. The LP+HL group showed an upregulation of transcription of peroxisome proliferator-activated receptor γ (+48%) and peroxisome proliferator-activated receptor γ coactivator α (+96%) compared with the LP+C group (P < .05), respectively. Similarly, gene expression of the markers of inflammation, nuclear factor-kappa B1 (+194%) and tumor necrosis factor-α (+192%), was enhanced (P < .05). Although other antioxidant enzymes were not modified in gene expression, catalase (CAT) was 66% higher in LP+HL compared with LP+C. In contrast, CAT protein content in the liver was 50% lower in LP groups compared with C, and superoxide dismutase 2 (SOD2) was twice as high in LP groups compared with C. Postweaning HL after maternal protein restriction induces hepatic metabolic adaptation characterized by enhanced oxidative stress, unbalanced expression in the antioxidant enzymes SOD1, SOD2 and CAT, and activation of inflammatory pathways but does not impact circulating markers of lipid metabolism and liver function.

The role of the canonical nf-κb signaling pathway in the development of acute liver failure

As a clinical emergency with a high mortality rate, the treatment of acute liver failure has been paid attention to by society. At present, liver transplantation is the most effective treatment for acute liver failure, but there is still an insufficient supply of liver sources and a poor prognosis. In view of the current therapeutic development of this disease, more researchers have turned their attention to the research of drugs related to the NF-κB pathway. The NF-κB canonical pathway has been proven to play a role in a variety of diseases, regulating inflammation, apoptosis, and other physiological processes. More and more evidence shows that the NF-κB canonical pathway regulates the pathogenesis of acute liver failure. In this review, we will summarize the regulation process of the NF-κB canonical pathway on acute liver failure, and develop a new way to treat acute liver failure by targeting the components of the pathway.

The Janus-Faced Role of Lipid Droplets in Aging: Insights from the Cellular Perspective

It is widely accepted that nine hallmarks-including mitochondrial dysfunction, epigenetic alterations, and loss of proteostasis-exist that describe the cellular aging process. Adding to this, a well-described cell organelle in the metabolic context, namely, lipid droplets, also accumulates with increasing age, which can be regarded as a further aging-associated process. Independently of their essential role as fat stores, lipid droplets are also able to control cell integrity by mitigating lipotoxic and proteotoxic insults. As we will show in this review, numerous longevity interventions (such as mTOR inhibition) also lead to strong accumulation of lipid droplets in Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, and mammalian cells, just to name a few examples. In mammals, due to the variety of different cell types and tissues, the role of lipid droplets during the aging process is much more complex. Using selected diseases associated with aging, such as Alzheimer's disease, Parkinson's disease, type II diabetes, and cardiovascular disease, we show that lipid droplets are "Janus"-faced. In an early phase of the disease, lipid droplets mitigate the toxicity of lipid peroxidation and protein aggregates, but in a later phase of the disease, a strong accumulation of lipid droplets can cause problems for cells and tissues.

Immuno-Biochemical Impacts of Gamma Irradiation in Male Rats: A Dose-Response Study

During radiotherapy, immune-modulatory effects of radiation doses should be taken into consideration, not only the anti-tumor radiation effects. Thus, our study aimed to study how γ-radiation modulates immune response in comparison to common immune-suppressive/stimulant agents. Animals were divided into two groups. Category A received Echinacea purpura extract (EP) or irradiated at low radiation doses 0, .25 or .5 Gray (Gy), whereas Category B received cyclophosphamide (CP) or irradiated at high radiation doses 1, 2, or 5 Gy. Serum levels of immunological mediators interleukin-10 (IL-10) and tumor necrosis factor (TNF-α), as well as redox-markers malondialdehyde (MDA) and nitric oxide (NO), hemoglobin (Hgb), white and red blood cells (WBCs, RBCs), and platelet counts were assessed following irradiation. Of the immune-stimulant category, .25 Gy dose offered EP-comparable effects in TNF-α, RBCs, Hgb, and platelet counts cases. As for the immune-suppressive category; 5 Gy irradiation dose induced inflammatory/immunosuppressive responses indicated (rise in NO, TNF-α, and IL-10), and an oxidative stress status (increase in serum MDA). However, 5 Gy γ-irradiation was not observed, herein, as a single immunosuppressive agent. To conclude, during radiotherapy, immunological impact(s) of the used radiation doses should be optimized and followed-up closely to assess the risk/benefit of their usage.

The mitigation mechanism of hesperidin on deoxynivalenol toxicity in grass carp hepatocytes via decreasing ROS accumulation and inhibiting JNK phosphorylation

Deoxynivalenol (DON), a crucial kind of mycotoxin, is found globally present in the contaminated cereal crops including wheat, barley, maize and rice. Hesperidin (HDN) is a flavonoid with a variety of biological activities found in high concentrations in citrus fruits. However, the potential protective effects of HDN on cell damage under DON toxicity, and the role of oxidative stress, inflammation, autophagy and apoptosis in it, remain unclear. Therefore, we treated grass carp (Ctenopharyngodon idellus) liver cells (L8824 cell) with DON and HDN for 24 h. The results showed that DON exposure caused a higher ROS accumulation, activated inflammation, autophagy and apoptosis, induced the expression of cytokines (NF-kappaB, TNF-α, IL-1β, IL-6), triggered BCL2/BAX-mediated apoptosis and LC3B/P62-dependent autophagy in the L8824 cell line. Moreover, HDN reduced DON exposure-induced inflammation and autophagy by decreasing ROS accumulation and reduced DON exposure-induced apoptosis by inhibiting JNK phosphorylation. These results partly explained the mechanism of biological threat on fish under DON exposure and the potential application value of HDN in aquaculture.

Synergic interactions between berry polyphenols and gut microbiota in cardiovascular diseases

Now a days, scientific community has been taking initiatives to decrease burden of metabolic disorders including diabetes mellitus, chronic hypertension, cardiovascular diseases and many others. Many nutraceuticals and functional food have a crucial function in preventing and decreasing burden of chronic diseases. Main purpose of the study was to relate association between mechanism of gut microbiota effecting cardiovascular diseases, moreover, to find out advantageous effects of berry polyphenols on gut microbiota and cardiovascular diseases. To summarize, we explore literature for beneficial effects of berry polyphenols by using multiple search engines including Google Scholar, Science Direct and PubMed. Original research article, review articles, experimental trials (human and animal studies) and abstract were also included in the current study based on relevancy to the characteristics of berries and their potential benefit on human health. This detailed review revealed that all classes of berries and their metabolites possess a definite impact on human health by preventing onset of chronic diseases by its anti-inflammatory property, thus, consider as one of the beneficial natural compounds that can be consumed on daily basis to prevent various disorders. There is also a positive association between berry polyphenols and modulation of gut microbiota and their metabolites, furthermore, showed a relationship between gut microbiome and incidence of cardiovascular disease.

Toxicities of amyloid-beta and tau protein are reciprocally enhanced in the Drosophila model

Extracellular aggregation of amyloid-beta (Aβ) and intracellular tau tangles are two major pathogenic hallmarks and critical factors of Alzheimer’s disease. A linear interaction between Aβ and tau protein has been characterized in several models. Aβ induces tau hyperphosphorylation through a complex mechanism; however, the master regulators involved in this linear process are still unclear. In our study with Drosophila melanogaster, we found that Aβ regulated tau hyperphosphorylation and toxicity by activating c-Jun N-terminal kinase. Importantly, Aβ toxicity was dependent on tau hyperphosphorylation, and flies with hypophosphorylated tau were insulated against Aβ-induced toxicity. Strikingly, tau accumulation reciprocally interfered with Aβ degradation and correlated with the reduction in mRNA expression of genes encoding Aβ-degrading enzymes, including dNep1, dNep3, dMmp2, dNep4, and dIDE. Our results indicate that Aβ and tau protein work synergistically to further accelerate Alzheimer’s disease progression and may be considered as a combined target for future development of Alzheimer’s disease therapeutics.

Role of oxidative stress-mediated cell death and signaling pathways in experimental fluorosis

Free radicals and other oxidants have enticed the interest of researchers in the fields of biology and medicine, owing to their role in several pathophysiological conditions, including fluorosis (Fluoride toxicity). Radical species affect cellular biomolecules such as nucleic acids, proteins, and lipids, resulting in oxidative stress. Reactive oxygen species-mediated oxidative stress is a common denominator in fluoride toxicity. Fluorosis is a global health concern caused by excessive fluoride consumption over time. Fluoride alters the cellular redox homeostasis, and its toxicity leads to the activation of cell death mechanisms like apoptosis, autophagy, and necroptosis. Even though a surfeit of signaling pathways is involved in fluorosis, their toxicity mechanisms are not fully understood. Thus, this review aims to understand the role of reactive species in fluoride toxicity with an outlook on the effects of fluoride in vitro and in vivo models. Also, we emphasized the signal transduction pathways and the mechanism of cell death implicated in fluoride-induced oxidative stress.

Protective Role of Mitochondrial Uncoupling Proteins against Age-Related Oxidative Stress in Type 2 Diabetes Mellitus

The accumulation of oxidative damage to DNA and other biomolecules plays an important role in the etiology of aging and age-related diseases such as type 2 diabetes mellitus (T2D), atherosclerosis, and neurodegenerative disorders. Mitochondrial DNA (mtDNA) is especially sensitive to oxidative stress. Mitochondrial dysfunction resulting from the accumulation of mtDNA damage impairs normal cellular function and leads to a bioenergetic crisis that accelerates aging and associated diseases. Age-related mitochondrial dysfunction decreases ATP production, which directly affects insulin secretion by pancreatic beta cells and triggers the gradual development of the chronic metabolic dysfunction that characterizes T2D. At the same time, decreased glucose oxidation in skeletal muscle due to mitochondrial damage leads to prolonged postprandial blood glucose rise, which further worsens glucose homeostasis. ROS are not only highly reactive by-products of mitochondrial respiration capable of oxidizing DNA, proteins, and lipids but can also function as signaling and effector molecules in cell membranes mediating signal transduction and inflammation. Mitochondrial uncoupling proteins (UCPs) located in the inner mitochondrial membrane of various tissues can be activated by ROS to protect cells from mitochondrial damage. Mitochondrial UCPs facilitate the reflux of protons from the mitochondrial intermembrane space into the matrix, thereby dissipating the proton gradient required for oxidative phosphorylation. There are five known isoforms (UCP1-UCP5) of mitochondrial UCPs. UCP1 can indirectly reduce ROS formation by increasing glutathione levels, thermogenesis, and energy expenditure. In contrast, UCP2 and UCP3 regulate fatty acid metabolism and insulin secretion by beta cells and modulate insulin sensitivity. Understanding the functions of UCPs may play a critical role in developing pharmacological strategies to combat T2D. This review summarizes the current knowledge on the protective role of various UCP homologs against age-related oxidative stress in T2D.

Scoparone Improves Nonalcoholic Steatohepatitis Through Alleviating JNK/Sab Signaling Pathway-Mediated Mitochondrial Dysfunction

The activated c-Jun N-terminal kinase (JNK) specifically combined with SH3 domain-binding protein 5 (Sab) may mediate damage to the mitochondrial respiratory chain. Whether mitochondrial dysfunction induced by the JNK/Sab signaling pathway plays a pivotal role in the lipotoxic injury of nonalcoholic steatohepatitis (NASH) remains a lack of evidence. Scoparone, a natural compound from Traditional Chinese Medicine herbs, has the potential for liver protection and lipid metabolism regulation. However, the effect of scoparone on NASH induced by a high-fat diet (HFD) as well as its underlying mechanism remains to be elucidated. The HepG2 and Huh7 cells with/without Sab-knockdown induced by palmitic acid (PA) were used to determine the role of JNK/Sab signaling in mitochondrial dysfunction and cellular lipotoxic injury. To observe the effect of scoparone on the lipotoxic injured hepatocytes, different dose of scoparone together with PA was mixed into the culture medium of HepG2 and AML12 cells to incubate for 24 h. In addition, male C57BL/6J mice were fed with an HFD for 22 weeks to induce the NASH model and were treated with scoparone for another 8 weeks to investigate its effect on NASH. Molecules related to JNK/Sab signaling, mitochondrial function, and lipotoxic injury were detected in in vitro and/or in vivo experiments. The results showed that PA-induced activation of JNK/Sab signaling was blocked by Sab knockdown in hepatocytes, which improved mitochondrial damage, oxidative stress, hepatosteatosis, cell viability, and apoptosis. Scoparone demonstrated a similar effect on the PA-induced hepatocytes as Sab knockdown. For the NASH mice, treatment with scoparone also downregulated the activation of JNK/Sab signaling, improved histopathological changes of liver tissues including mitochondrial number and morphology, lipid peroxide content, hepatosteatosis and inflammation obviously, as well as decreased the serum level of lipid and transaminases. Taken together, this study confirms that activation of the JNK/Sab signaling pathway-induced mitochondrial dysfunction plays a crucial role in the development of NASH. Scoparone can improve the lipotoxic liver injury partially by suppressing this signaling pathway, making it a potential therapeutic compound for NASH.

Anticancer potential and through study of the cytotoxicity mechanism of ionic liquids that are based on the trifluoromethanesulfonate and bis(trifluoromethylsulfonyl)imide anions

Ionic liquids (ILs) are known for their unique physicochemical properties. However, despite the great number of published papers, still little attention has been paid to their biological activity. Anticancer potential and the molecular mechanisms underlying the toxicity of these compounds are especially interesting and still unexplored. In the current work, a broad analysis of the cytotoxicity towards colon and breast cancers as well as glioblastoma of the ILs with pyridinium, piperidinium, pyrrolidinium, and imidazolium cations and trifluoromethanesulfonate or bis(trifluoromethylsulfonyl)imide anions indicated previously as the most toxic for normal human dermal fibroblasts were presented. In the case of MCF-7 cells, the activity of 1-decyl-3-methylimidazolium trifluoromethanesulfonate was more than twice as high as cisplatin. It was found that the inhibition of the cell cycle of colon cancer and glioblastoma cells occurs in different phases. More importantly, the different types of cell death were detected for both selected ILs, namely 1-hexyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and 1-hexyl-3-methylimidazolium trifluoromethane-sulfonate, on colon cancer and glioblastoma, respectively, apoptosis and autophagy, confirmed at the gene and protein levels. Additionally, kinetic studies of the reactive oxygen species indicated that the tested ILs disturbed the cellular redox homeostasis.

Secondary Mania induced by TNF-α inhibitors: A systematic review

A growing number of studies support a bidirectional relationship between inflammation and bipolar disorders. Tumor necrosis factor-α (TNF-α) inhibitors have recently attracted interest as potential therapeutic compounds for treating depressive symptoms, but the risk for triggering mood switches in patients with or without bipolar disorders remains controversial. Thus, we conducted a systematic review to study the anti-TNF-α medication-induced manic or hypomanic episodes. PubMed, Scopus, Medline, and Embase databases were screened for a comprehensive literature search from inception until November 2020, using The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Out of the initial 75 references, the screening resulted in the inclusion of four case reports (each describing one patient) and a cohort study (in which 40 patients out of 7600-0.53% - experienced elated mood episodes after infliximab administration). Of these 44 patients, 97.7% experienced a manic episode and 2.3% hypomania. 93.2% of patients had no history of psychiatric disorder or psychotropic treatment. Only 6.8% had a history of psychiatric disorders with the affective spectrum (4.6% dysthymia and 2.3% bipolar disorder). The time of onset of manic or hypomanic symptoms varied across TNF-α inhibitors with an early onset for Infliximab and a later onset for Adalimumab and Etanercept. These findings suggest that medications targeting the TNF-α pathway may trigger a manic episode in patients with or without affective disorders. However, prospective studies are needed to evaluate the relative risk of such side effects and identify the population susceptible to secondary mania.

Therapeutics effect of mesenchymal stromal cells in reactive oxygen species-induced damages

Reactive Oxygen Species are chemically unstable molecules generated during aerobic respiration, especially in the electron transport chain. ROS are involved in various biological functions; any imbalance in their standard level results in severe damage, for instance, oxidative damage, inflammation in a cellular system, and cancer. Oxidative damage activates signaling pathways, which result in cell proliferation, oncogenesis, and metastasis. Since the last few decades, mesenchymal stromal cells have been explored as therapeutic agents against various pathologies, such as cardiovascular diseases, acute and chronic kidney disease, neurodegenerative diseases, macular degeneration, and biliary diseases. Recently, the research community has begun developing several anti-tumor drugs, but these therapeutic drugs are ineffective. In this present review, we would like to emphasize MSCs-based targeted therapy against pathologies induced by ROS as cells possess regenerative potential, immunomodulation, and migratory capacity. We have also focused on how MSCs can be used as next-generation drugs with no side effects.

Advanced preclinical models for evaluation of drug-induced liver injury - consensus statement by the European Drug-Induced Liver Injury Network [PRO-EURO-DILI-NET]

Drug-induced liver injury (DILI) is a major cause of acute liver failure (ALF) and one of the leading indications for liver transplantation in Western societies. Given the wide use of both prescribed and over the counter drugs, DILI has become a major health issue for which there is a pressing need to find novel and effective therapies. Although significant progress has been made in understanding the molecular mechanisms underlying DILI, our incomplete knowledge of its pathogenesis and inability to predict DILI is largely due to both discordance between human and animal DILI in preclinical drug development and a lack of models that faithfully recapitulate complex pathophysiological features of human DILI. This is exemplified by the hepatotoxicity of acetaminophen (APAP) overdose, a major cause of ALF because of its extensive worldwide use as an analgesic. Despite intensive efforts utilising current animal and in vitro models, the mechanisms involved in the hepatotoxicity of APAP are still not fully understood. In this expert Consensus Statement, which is endorsed by the European Drug-Induced Liver Injury Network, we aim to facilitate and outline clinically impactful discoveries by detailing the requirements for more realistic human-based systems to assess hepatotoxicity and guide future drug safety testing. We present novel insights and discuss major players in APAP pathophysiology, and describe emerging in vitro and in vivo pre-clinical models, as well as advanced imaging and in silico technologies, which may improve prediction of clinical outcomes of DILI.

Pulmonary toxicity of actual alveolar deposition concentrations of ultrafine particulate matters in human normal bronchial epithelial cell

Air pollution is a major worldwide concern, and exposure to particulate matter (PM) can increase the risks of pulmonary diseases. Normal human bronchial epithelial cells were applied to clarify the role of ultrafine PM (UFPM) in the pathogenesis of pulmonary toxic effects with realistic alveolar deposition doses. The UFPM used in this research originated from vehicular emissions and coal combustion. UFPM exposure of up to 72 h was found to induce significant time- and concentration-dependent decreases in cell viability. Exposure to UFPM increased reactive oxygen species (ROS) accumulation through heme oxygenase-1 (HO-1) inhibition and induced massive oxidative stress that increased the interleukin-8 (IL-8) expression. UFPM also reduced the pulmonary trans-epithelial electrical resistance through the depletion of zonula occludens (ZO) proteins. Finally, UFPM decreased the α1-antitrypsin (A1AT) expression, which implies high risk of chronic obstructive pulmonary disease (COPD). The evidence demonstrates that exposure to UFPM, even at very low concentrations, may affect the functions of the respiratory system.

Hepatoprotective effect of kaempferol glycosides isolated from Cedrela odorata L. leaves in albino mice: involvement of Raf/MAPK pathway

Background and purpose:

Paracetamol is the most implicated xenobiotic in inducing hepatotoxicity. Our study aimed to determine the impact of some kaempferol glycosides isolated from the leaves of Cedrela odorata L. on paracetamol hepatotoxicity.

Experimental approach:

The methanolic extract of dried leaves of C. odorata L. was subjected to the combination of spectroscopic methods (¹H and ¹³CNMR). Six kaempferol glycosides were isolated: kaempferol-3-O-β-D-glycopyranoside (astragalin), kaempferol-3-O-β-L-rhamnopyranoside, kaempferol-3-O-β-D-rutinoside, kaempferide-3-O-β-D-rutinoside, kaempferide-3-O-β-Drutinosyl-7-O-β-D-rhamnopyranoside, and kaempferol-3-O-β-D- rutinosyl-7-O-a-D-arabinopyranoside. Fifty-four female Swiss Albino mice were divided randomly into 9 groups including (1) control negative (1 mL/kg saline; IP), (2) control positive (paracetamol 300 mg/kg; IP), (3) silymarin 50 mg/kg (IP). Animals of groups 4-9 were injected with 6 different samples of isolated compounds at 100 mg/kg (IP). One h later, groups 3-9 were injected with paracetamol (300 mg/kg IP). Two h later, tissue samples were taken from all animals to assess nitrotyrosine, c-Jun N-terminal protein kinase (c-JNK), Raf -1kinase, and oxidative stress biomarkers viz. reduced glutathione (GSH) and malondialdehyde (MDA).

Findings/Results:

Isolated glycosides had a prominent anti-apoptotic effect via inhibition of c-JNK and Raf-1 kinase. They also exerted a powerful antioxidant effect by modulating the oxidative stress induced by paracetamol via increasing GSH, reducing MDA and nitrotyrosine concentrations compared to positive control. The glycoside (1) showed a better effect than silymarin (standard) in ameliorating the formation of nitrotyrosine, Raf-1 kinase, c-JNK, and GSH.

Conclusion and implication:

Kaempferol glycosides isolated for the first time from C. odorata L. leaves exerted antioxidant and antiapoptotic effects via amelioration of oxidative stress and inhibition of Raf/MAPK pathway.

Xenotransplantation of tannic acid-encapsulated neonatal porcine islets decreases proinflammatory innate immune responses

BACKGROUND

Islet transplantation with neonatal porcine islets (NPIs) is a promising treatment for type 1 diabetes (T1D), but immune rejection poses a major hurdle for clinical use. Innate immune-derived reactive oxygen species (ROS) synthesis can facilitate islet xenograft destruction and enhance adaptive immune responses.

METHODS

To suppress ROS-mediated xenograft destruction, we utilized nanothin encapsulation materials composed of multilayers of tannic acid (TA), an antioxidant, and a neutral polymer, poly(N-vinylpyrrolidone) (PVPON). We hypothesized that (PVPON/TA)-encapsulated NPIs will maintain euglycemia and dampen proinflammatory innate immune responses following xenotransplantation.

RESULTS

(PVPON/TA)-encapsulated NPIs were viable and glucose-responsive similar to non-encapsulated NPIs. Transplantation of (PVPON/TA)-encapsulated NPIs into hyperglycemic C57BL/6.Rag or NOD.Rag mice restored euglycemia, exhibited glucose tolerance, and maintained islet-specific transcription factor levels similar to non-encapsulated NPIs. Gene expression analysis of (PVPON/TA)-encapsulated grafts post-transplantation displayed reduced proinflammatory Ccl5, Cxcl10, Tnf, and Stat1 while enhancing alternatively activated macrophage Retnla, Arg1, and Stat6 mRNA accumulation compared with controls. Flow cytometry analysis demonstrated significantly reduced innate immune infiltration, MHC-II, co-stimulatory molecule, and TNF expression with concomitant increases in arginase-1⁺ macrophages and dendritic cells. Similar alterations in immune responses were observed following xenotransplantation into immunocompetent NOD mice.

CONCLUSION

Our data suggest that (PVPON/TA) encapsulation of NPIs is an effective strategy to decrease inflammatory innate immune signals involved in NPI xenograft responses through STAT1/6 modulation without compromising islet function.

AWP1 Restrains the Aggressive Behavior of Breast Cancer Cells Induced by TNF-α

TNF-α plays a crucial role in cancer initiation and progression by enhancing cancer cell proliferation, survival, and migration. Even though the known functional role of AWP1 (zinc finger AN1 type-6, ZFAND6) is as a key mediator of TNF-α signaling, its potential role in the TNF-α-dependent responses of cancer cells remains unclear. In our current study, we found that an AWP1 knockdown using short hairpin RNAs increases the migratory potential of non-aggressive MCF-7 breast cancer cells with no significant alteration of their proliferation in response to TNF-α. A CRISPR/Cas9-mediated AWP1 knockout in MCF-7 cells led to mesenchymal cell type morphological changes and an accelerated motility. TNF-α administration further increased this migratory capacity of these AWP1-depleted cells through the activation of NF-κB accompanied by increased epithelial-mesenchymal transition-related gene expression. In particular, an AWP1 depletion augmented the expression of Nox1, reactive oxygen species (ROS) generating enzymes, and ROS levels and subsequently promoted the migratory potential of MCF-7 cells mediated by TNF-α. These TNF-α-mediated increases in the chemotactic migration of AWP1 knockout cells were completely abrogated by an NF-κB inhibitor and a ROS scavenger. Our results suggest that a loss-of-function of AWP1 alters the TNF-α response of non-aggressive breast cancer cells by potentiating ROS-dependent NF-κB activation.

Apigenin protects mice against 3,5-diethoxycarbonyl-1,4-dihydrocollidine-induced cholestasis

Cholestasis can induce liver fibrosis and cirrhosis. Apigenin has anti-oxidant and anti-inflammatory effects. Herein, we determined whether apigenin can protect mice against cholestasis. In vitro, apigenin protected TFK-1 cells (a human bile duct cancer cell line) against H2O2-induced ROS generation and inhibited transforming growth factor-β-activated collagen type 1 alpha 1 and α-smooth muscle actin in LX2 cells (a human hepatic stellate cell line). In vivo, cholestatic mice induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) were treated with apigenin. Apigenin potently blocked DDC-induced gallbladder atrophy and associated liver injury, fibrosis and collagen accumulation. Moreover, apigenin relieved the DDC-caused abnormality of bile acid metabolism and restored the balance between bile secretion and excretion by regulating the farnesoid X receptor signaling pathway. Furthermore, apigenin reduced inflammation or oxidative stress in the liver by blocking the DDC-activated Toll-like receptor 4, nuclear factor κB and tumor necrosis factor α, or DDC-suppressed superoxidase dismutase 1/2, catalase and glutathione peroxidase. Taken together, apigenin improves DDC-induced cholestasis by reducing inflammation and oxidative damage and improving bile acid metabolism, indicating its potential application for cholestasis treatment.

Berry-Derived Polyphenols in Cardiovascular Pathologies: Mechanisms of Disease and the Role of Diet and Sex

Cardiovascular disease (CVD) prevalence, pathogenesis, and manifestation is differentially influenced by biological sex. Berry polyphenols target several signaling pathways pertinent to CVD development, including inflammation, oxidative stress, and cardiac and vascular remodeling, and there are innate differences in these pathways that also vary by sex. There is limited research systematically investigating sex differences in berry polyphenol effects on these pathways, but there are fundamental findings at this time that suggest a sex-specific effect. This review will detail mechanisms within these pathological pathways, how they differ by sex, and how they may be individually targeted by berry polyphenols in a sex-specific manner. Because of the substantial polyphenolic profile of berries, berry consumption represents a promising interventional tool in the treatment and prevention of CVD in both sexes, but the mechanisms in which they function within each sex may vary.

Association between dynapenic abdominal obesity and inflammatory profile in diabetic older community-dwelling patients with end-stage renal disease

BACKGROUND

Obesity and poor strength impose higher risk factor for end-stage renal disease (ESRD) patients. It is expected that the combination of both conditions might be critically associated with the inflammatory profile in this population, especially in community-dwelling elderly. So, diagnosis of dynapenic obesity and inflammation is an important tool in the management of chronic kidney disease patients at imminent risk of hospitalization.

PURPOSE

To investigate the association between dynapenic abdominal obesity and inflammatory markers in community-swelling elderly with ESRD.

METHODS

Two hundred and forty-seven community-dwelling older patients (66.74 ± 3.20 years; n = 150, 60.73%, males) undergoing maintenance phase hemodialysis volunteered for this study. The study sample was categorized into four groups according to handgrip strength and waist circumference as follows: control, dynapenia (low strength alone), abdominal obesity (high waist circumference alone), and dynapenic obesity (D/AO) (the combination of low strength and high waist circumference). Blood samples were collected for tumor necrosis factor alpha (TNF-α), interleukin (IL)- 6 and IL- 10. Results were considered significant at P < 0.05.

RESULTS

Proportions for control, abdominal obesity, dynapenic, and D/AO were 38.5%, 15.8%, 25.9%, and 19.8%, respectively. Higher concentrations of TNF-α were found in the D/AO group (P < 0.0001). This group also displayed lower levels of IL-10 (P < 0.0001). Further, the D/AO traits were strongly associated with TNF-α and IL-10 (P < 0.0001).

CONCLUSION

The closely relation between D/AO and inflammatory profile provides evidence that the pooled information of low muscle strength and abdominal obesity may be clinically relevant for the management of ESRD patients.

Immunomodulatory role of reactive oxygen species and nitrogen species during T cell-driven neutrophil-enriched acute and chronic cutaneous delayed-type hypersensitivity reactions

Rationale: Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are important regulators of inflammation. The exact impact of ROS/RNS on cutaneous delayed-type hypersensitivity reaction (DTHR) is controversial. The aim of our study was to identify the dominant sources of ROS/RNS during acute and chronic trinitrochlorobenzene (TNCB)-induced cutaneous DTHR in mice with differently impaired ROS/RNS production. Methods: TNCB-sensitized wild-type, NADPH oxidase 2 (NOX2)- deficient (gp91^phox-/-), myeloperoxidase-deficient (MPO^-/-), and inducible nitric oxide synthase-deficient (iNOS^-/-) mice were challenged with TNCB on the right ear once to elicit acute DTHR and repetitively up to five times to induce chronic DTHR. We measured ear swelling responses and noninvasively assessed ROS/RNS production in vivo by employing the chemiluminescence optical imaging (OI) probe L-012. Additionally, we conducted extensive ex vivo analyses of inflamed ears focusing on ROS/RNS production and the biochemical and morphological consequences. Results: The in vivo L-012 OI of acute and chronic DTHR revealed completely abrogated ROS/RNS production in the ears of gp91^phox-/- mice, up to 90 % decreased ROS/RNS production in the ears of MPO^-/- mice and unaffected ROS/RNS production in the ears of iNOS^-/- mice. The DHR flow cytometry analysis of leukocytes derived from the ears with acute DTHR confirmed our in vivo L-012 OI results. Nevertheless, we observed no significant differences in the ear swelling responses among all the experimental groups. The histopathological analysis of the ears of gp91^phox-/- mice with acute DTHRs revealed slightly enhanced inflammation. In contrast, we observed a moderately reduced inflammatory immune response in the ears of gp91^phox-/- mice with chronic DTHR, while the inflamed ears of MPO^-/- mice exhibited the strongest inflammation. Analyses of lipid peroxidation, 8-hydroxy-2'deoxyguanosine levels, redox related metabolites and genomic expression of antioxidant proteins revealed similar oxidative stress in all experimental groups. Furthermore, inflamed ears of wild-type and gp91^phox-/- mice displayed neutrophil extracellular trap (NET) formation exclusively in acute but not chronic DTHR. Conclusions: MPO and NOX2 are the dominant sources of ROS/RNS in acute and chronic DTHR. Nevertheless, depletion of one primary source of ROS/RNS exhibited only marginal but conflicting impact on acute and chronic cutaneous DTHR. Thus, ROS/RNS are not a single entity, and each species has different properties at certain stages of the disease, resulting in different outcomes.

N-Acetylcysteine: A potential therapeutic agent for SARS-CoV-2

COVID-19, a respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to spread across the globe. Predisposing factors such as age, diabetes, cardiovascular disease, and lowered immune function increase the risk of disease severity. T cell exhaustion, high viral load, and high levels of TNF-ɑ, IL1β, IL6, IL10 have been associated with severe SARS-CoV-2. Cytokine and antigen overstimulation are potentially responsible for poor humoral response to the virus. Lower cellular redox status, which leads to pro-inflammatory states mediated by TNF-ɑ is also potentially implicated. In vivo, in vitro, and human clinical trials have demonstrated N-acetylcysteine (NAC) as an effective method of improving redox status, especially when under oxidative stress. In human clinical trials, NAC has been used to replenish glutathione stores and increase the proliferative response of T cells. NAC has also been shown to inhibit the NLRP3 inflammasome pathway (IL1β and IL18) in vitro, and decrease plasma TNF-ɑ in human clinical trials. Mediation of the viral load could occur through NAC's ability to increase cellular redox status via maximizing the rate limiting step of glutathione synthesis, and thereby potentially decreasing the effects of virally induced oxidative stress and cell death. We hypothesize that NAC could act as a potential therapeutic agent in the treatment of COVID-19 through a variety of potential mechanisms, including increasing glutathione, improving T cell response, and modulating inflammation. In this article, we present evidence to support the use of NAC as a potential therapeutic agent in the treatment of COVID-19.

Shikonin overcomes drug resistance and induces necroptosis by regulating the miR-92a-1-5p/MLKL axis in chronic myeloid leukemia

Development of resistance to tyrosine kinase inhibitors (TKIs) targeting the BCR/ABL fusion protein represents a major challenge in the treatment of chronic myeloid leukemia (CML). Since apoptosis resistance is the fundamental mechanism impeding TKIs' therapeutic effects, alternative approaches that induce nonapoptotic cell death are being pursued to treat TKI-resistant CML. Induction of necroptosis, a distinct, caspase-independent form of programmed cell death, may be a valuable strategy in this respect. The present study shows that shikonin, an herbal compound used in traditional Chinese medicine, overcomes TKI resistance in BCR/ABL-positive CML cells by inducing necroptosis via activation of RIPK1/RIPK3/MLKL signaling. This effect occurs both in vitro and in vivo and involves downregulation of miR-92a-1-5p, a poor-prognosis marker frequently overexpressed in leukemia patients. Based on gene expression experiments, we conclude that miR-92a-1-5p promotes CML progression by inhibiting MLKL expression. Accordingly, we show that antagomiR-mediated in vivo inhibition of miR-92a-1-5p reduces the growth of CML tumors in mice through necroptosis induction. Our research suggests that therapies that relieve MLKL suppression by targeting miR-92a-1-5p may represent a useful strategy to treat TKI-refractory CML.

Water-Soluble Pristine C60 Fullerene Inhibits Liver Alterations Associated with Hepatocellular Carcinoma in Rat

Excessive production of reactive oxygen species is the main cause of hepatocellular carcinoma (HCC) initiation and progression. Water-soluble pristine C₆₀ fullerene is a powerful and non-toxic antioxidant, therefore, its effect under rat HCC model and its possible mechanisms were aimed to be discovered. Studies on HepG2 cells (human HCC) demonstrated C₆₀ fullerene ability to inhibit cell growth (IC₅₀ = 108.2 μmol), to induce apoptosis, to downregulate glucose-6-phosphate dehydrogenase, to upregulate vimentin and p53 expression and to alter HepG2 redox state. If applied to animals experienced HCC in dose of 0.25 mg/kg per day starting at liver cirrhosis stage, C₆₀ fullerene improved post-treatment survival similar to reference 5-fluorouracil (31 and 30 compared to 17 weeks) and inhibited metastasis unlike the latter. Furthermore, C₆₀ fullerene substantially attenuated liver injury and fibrosis, decreased liver enzymes, and normalized bilirubin and redox markers (elevated by 1.7–7.7 times under HCC). Thus, C₆₀ fullerene ability to inhibit HepG2 cell growth and HCC development and metastasis and to improve animal survival was concluded. C₆₀ fullerene cytostatic action might be realized through apoptosis induction and glucose-6-phosphate dehydrogenase downregulation in addition to its antioxidant activity.

Phagocytosis-related NADPH oxidase 2 subunit gp91phox contributes to neurodegeneration after repeated systemic challenge with lipopolysaccharides

Repeated systemic challenge with lipopolysaccharides (LPS) can induce microglia activation and inflammatory neurodegeneration in the substantia nigra pars compacta region of mice. We now explored the role of mononuclear phagocytes associated nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX-2) in inflammatory neurodegeneration. Cybb-deficient NOX-2 knock-out (KO) and control wild type (WT) mice were treated intraperitoneally daily over four consecutive days with 1 μg/gbw/day LPS. Transcriptome analysis by RNA-seq of total brain tissue indicated increased LPS-induced upregulation of genes belonging to the reactive oxygen species and reactive nitrogen species production, complement and lysosome activation as well as apoptosis and necroptosis in WT compared to NOX-2 KO mice. Validation of up-regulated gene transcripts via qRT-PCR confirmed that LPS-challenged NOX-2 KO mice expressed lower levels of the microglial phagocytosis-related genes Nos2, Cd68, Aif1/Iba1, Cyba, Itgam, and Fcer1g compared to WT mice at Day 5 after systemic inflammatory challenge, but no significant differences in the pro-inflammatory genes Tnfα and Il1b as well as microglial IBA1 and CD68 intensities were observed between both genotypes. Furthermore, loss of tyrosine hydroxylase positive (TH+) and NeuN positive neurons in the substantia nigra pars compacta upon repeated systemic LPS application were attenuated in NOX-2 KO mice. Thus, our data demonstrate that loss of dopaminergic neurons in the substantia nigra pars compacta after repeated systemic challenge with LPS is associated with a microglial phagocytosis-related gene activation profile involving the NADPH oxidase subunit Cybb/gp91phox.

Redox Control of the Immune Response in the Hepatic Progenitor Cell Niche

The liver commonly self-regenerates by a proliferation of mature cell types. Nevertheless, in case of severe or protracted damage, the organ renewal is mediated by the hepatic progenitor cells (HPCs), adult progenitors capable of differentiating toward the biliary and the hepatocyte lineages. This regeneration process is determined by the formation of a stereotypical niche surrounding the emerging progenitors. The organization of the HPC niche microenvironment is crucial to drive biliary or hepatocyte regeneration. Furthermore, this is the site of a complex immunological activity mediated by several immune and non-immune cells. Indeed, several cytokines produced by monocytes, macrophages and T-lymphocytes may promote the activation of HPCs in the niche. On the other side, HPCs may produce pro-inflammatory cytokines induced by liver inflammation. The inflamed liver is characterized by high generation of reactive oxygen and nitrogen species, which in turn lead to the oxidation of macromolecules and the alteration of signaling pathways. Reactive species and redox signaling are involved in both the immunological and the adult stem cell regeneration processes. It is then conceivable that redox balance may finely regulate the immune response in the HPC niche, modulating the regeneration process and the immune activity of HPCs. In this perspective article, we summarize the current knowledge on the role of reactive species in the regulation of hepatic immunity, suggesting future research directions for the study of redox signaling on the immunomodulatory properties of HPCs.

High Glucose Exacerbates TNF-α-Induced Proliferative Inhibition in Human Periodontal Ligament Stem Cells through Upregulation and Activation of TNF Receptor 1

Objective

This research is aimed at investigating how high glucose affects the proliferation and apoptosis in periodontal ligament stem cells (PDLSCs) in the presence of TNF-α.

Methods

PDLSCs obtained from periodontal healthy permanent teeth were treated under either high-glucose condition (30 mmol/L, G30 group) or normal glucose condition (5.6 mmol/L, G5.6 group) in the presence or absence of TNF-α (10 ng/ml) for 2 to 6 days. Cell proliferation and cell cycle were evaluated by CCK-8, EdU incorporation assay, and flow cytometry. Cell apoptosis was assessed by annexin V/PI staining. Protein expression was detected by western blotting. Cellular ROS expression was evaluated by CellROX labeling and flow cytometry. Specific antibodies targeting TNFR1 and TNFR2 were used to block TNF-α signaling. Vitamin C was also used to verify if the blockage of ROS can rescue PDLSCs in the presence of high glucose and TNF-α.

Results

CCK-8 assay showed that high glucose exacerbated TNF-α-induced cell viability inhibition (57.0%, 85.2%, and 100% for the G30+TNF-α group, G5.6+TNF-α group, and control group, respectively) on day 6. High glucose increased protein expression of TNFR1 compared with the control group on day 2 (1.24-fold) and day 6 (1.26-fold). Blocking TNFR1 totally reversed the proliferative inhibition in G30+TNF-α group. The addition of vitamin C or TNFR1 antibody totally reversed the elevation of intracellular ROS expression caused by high glucose and TNF-α. Vitamin C partially restored cell proliferation in the presence of high glucose and TNF-α.

Conclusion

High glucose exacerbates TNF-α-induced proliferative inhibition in human periodontal ligament stem cells through the upregulation and activation of TNF receptor 1. Inhibition of intracellular ROS expression by vitamin C partially rescues PDLSCs in terms of cell proliferation.

Gostner J, Kurz K. Pharmacological Targets of Kaempferol Within Inflammatory Pathways-A Hint Towards the Central Role of Tryptophan Metabolism

The flavonoid kaempferol is almost ubiquitously contained in edible and medicinal plants and exerts a broad range of interesting pharmacological activities. Interactions with central inflammatory processes can be exploited to treat or attenuate symptoms of disorders associated with chronic immune activation during infections, malignancies, and neurodegenerative or cardiovascular disorders. Many drugs, phytochemicals, and nutritional components target the catabolism of the essential amino acid tryptophan by indoleamine 2,3-dioxygenase 1 (IDO-1) for immunomodulation. We studied the effects of kaempferol by in vitro models with human peripheral blood mononuclear cells (PBMC) and THP-1 derived human myelomonocytic cell lines. Kaempferol suppressed interferon-γ dependent immunometabolic pathways: Formation of the oxidative stress biomarker neopterin and catabolism of tryptophan were inhibited dose-dependently in stimulated cells. In-silico docking studies revealed a potential interaction of kaempferol with the catalytic domain of IDO-1. Kaempferol stimulated nuclear factor kappa B (NF-κB) signaling in lipopolysaccharide (LPS)-treated THP-1 cells, thereby increasing the mRNA expression of interleukin (IL) 1 beta, tumor necrosis factor, and nuclear factor kappa B subunit 1, while IL6 was downregulated. Data suggest that concerted effects of kaempferol on multiple immunologically relevant targets are responsible for its immunomodulatory activity. However, the immunosuppressive effects may be more relevant in a T-cell dominated context.

Cellular Interplay as a Consequence of Inflammatory Signals Leading to Liver Fibrosis Development

Inflammation has been known to be an important driver of fibrogenesis in the liver and onset of hepatic fibrosis. It starts off as a process meant to protect the liver from further damage, but it can become the main promoter of liver fibrosis. There are many inflammation-related pathways activated during liver fibrosis that lead to hepatic stellate cells (HSCs) activation and collagen-deposition in the liver. Such events are mostly modulated upstream of HSCs and involve signals from hepatocytes and innate immune cells. One particular event is represented by cell death during liver injury that generates multiple inflammatory signals that further trigger sterile inflammation and enhancement of inflammatory response. The assembly of inflammasome that responds to danger-associated molecular patterns (DAMPs) stimulates the release of pro-inflammatory cytokines and at the same time, initiates programmed cell death called pyroptosis. This review focuses on cellular and molecular mechanisms responsible for initiation and progress of inflammation in the liver.

Future Therapeutic Directions for Smac-Mimetics

It is well accepted that the ability of cancer cells to circumvent the cell death program that untransformed cells are subject to helps promote tumor growth. Strategies designed to reinstate the cell death program in cancer cells have therefore been investigated for decades. Overexpression of members of the Inhibitor of APoptosis (IAP) protein family is one possible mechanism hindering the death of cancer cells. To promote cell death, drugs that mimic natural IAP antagonists, such as second mitochondria-derived activator of caspases (Smac/DIABLO) were developed. Smac-Mimetics (SMs) have entered clinical trials for hematological and solid cancers, unfortunately with variable and limited results so far. This review explores the use of SMs for the treatment of cancer, their potential to synergize with up-coming treatments and, finally, discusses the challenges and optimism facing this strategy.

Redox Proteomes in Human Physiology and Disease Mechanisms

Redox proteomics is a field of proteomics that is concerned with the characterization of the oxidation state of proteins to gain information about their modulated structure, function, activity, and involvement in different physiological pathways. Oxidative modifications of proteins have been shown to be implicated in normal physiological processes of cells as well as in pathomechanisms leading to the development of cancer, diabetes, neurodegenerative diseases, and some rare hereditary metabolic diseases, like classic galactosemia. Reactive oxygen species generate a variety of reversible and irreversible modifications in amino acid residue side chains and within the protein backbone. These oxidative post-translational modifications (Ox-PTMs) can participate in the activation of signal transduction pathways and mediate the toxicity of harmful oxidants. Thus the application of advanced redox proteomics technologies is important for gaining insights into molecular mechanisms of diseases. Mass-spectrometry-based proteomics is one of the most powerful methods that can be used to give detailed qualitative and quantitative information on protein modifications and allows us to characterize redox proteomes associated with diseases. This Review illustrates the role and biological consequences of Ox-PTMs under basal and oxidative stress conditions by focusing on protein carbonylation and S-glutathionylation, two abundant modifications with an impact on cellular pathways that have been intensively studied during the past decade.

Beneficial and Deleterious Effects of Female Sex Hormones, Oral Contraceptives, and Phytoestrogens by Immunomodulation on the Liver

The liver is considered the laboratory of the human body because of its many metabolic processes. It accomplishes diverse activities as a mixed gland and is in continuous cross-talk with the endocrine system. Not only do hormones from the gastrointestinal tract that participate in digestion regulate the liver functions, but the sex hormones also exert a strong influence on this sexually dimorphic organ, via their receptors expressed in liver, in both health and disease. Besides, the liver modifies the actions of sex hormones through their metabolism and transport proteins. Given the anatomical position and physiological importance of liver, this organ is evidenced as an immune vigilante that mediates the systemic immune response, and, in turn, the immune system regulates the hepatic functions. Such feedback is performed by cytokines. Pro-inflammatory and anti-inflammatory cytokines are strongly involved in hepatic homeostasis and in pathological states; indeed, female sex hormones, oral contraceptives, and phytoestrogens have immunomodulatory effects in the liver and the whole organism. To analyze the complex and interesting beneficial or deleterious effects of these drugs by their immunomodulatory actions in the liver can provide the basis for either their pharmacological use in therapeutic treatments or to avoid their intake in some diseases.

GKN2 promotes oxidative stress-induced gastric cancer cell apoptosis via the Hsc70 pathway

BACKGROUND

The GKN2 is a secretory protein, whose levels decrease in gastric cancer. The present study aimed to investigate the expression, function and mechanism of action of GKN2 in gastric cancer.

METHODS

Molecular biology assays were performed to elucidate the function and underlying mechanisms of GKN2 in gastric cancer under stress-induced condition in vivo and in vitro. Clinical specimens were used to assess the correlation of GKN2 and prognosis.

RESULTS

We found that overexpression of GKN2 significantly enhanced apoptosis and growth arrest in vitro. GKN2 expression increased in gastric cancer cells exposed to hydrogen peroxide and promoted reactive oxygen species-induced mitochondrial dysfunction and resulted in increased cell apoptosis via inhibition of NF-κB signaling pathway and activation of JNK signaling pathway through the direct interaction of GKN2 with Hsc70. Trefoil factor 1 might contribute to the tumor suppressing effects of GKN2. MiR-216a downregulated GKN2 expression. GKN2 also inhibited xenograft tumor growth and was an independent and significant prognostic factor for patients with gastric cancer treated with oxaliplatin.

CONCLUSIONS

Taken together, our data indicate that GKN2 may increase sensitivity of GC cells to the drugs which increase ROS levels in tumors. Inhibition of the interaction between GKN2 and Hsc70 could attenuate the effects induced by GKN2. GKN2 overexpression could be used to determine the subgroup of patients to obtain the more favorable outcome of oxaliplatin treatment and may be used as biomarker of the prognosis of this cancer.

The cyclic nitroxide antioxidant 4-methoxy-TEMPO decreases mycobacterial burden in vivo through host and bacterial targets

Tuberculosis is a chronic inflammatory disease caused by persistent infection with Mycobacterium tuberculosis. The rise of antibiotic resistant strains necessitates the design of novel treatments. Recent evidence shows that not only is M. tuberculosis highly resistant to oxidative killing, it also co-opts host oxidant production to induce phagocyte death facilitating bacterial dissemination. We have targeted this redox environment with the cyclic nitroxide derivative 4-methoxy-TEMPO (MetT) in the zebrafish-M. marinum infection model. MetT inhibited the production of mitochondrial ROS and decreased infection-induced cell death to aid containment of infection. We identify a second mechanism of action whereby stress conditions, including hypoxia, found in the infection microenvironment appear to sensitise M. marinum to killing by MetT both in vitro and in vivo. Together, our study demonstrates MetT inhibited the growth and dissemination of M. marinum through host and bacterial targets.

Methyl 3,4-dihydroxybenzoate protects against d-galN/LPS-induced acute liver injury by inhibiting inflammation and apoptosis in mice

Objectives

Aimed to investigate the effect and mechanism of methyl 3,4-dihydroxybenzoate (MDHB) on d-galactosamine/lipopolysaccharide (d-galN/LPS)-induced acute liver failure (ALF).

Methods

Confirmed the hepatoprotective effect and hepatotoxicity of MDHB by histopathological examination (HE) and examination of alanine aminotransferase (ALT) and aspartate aminotransferase (AST); the expression of serum tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6) was detected by ELISA; transcription levels of TNF-α, IL-1β, IL-6 and Toll-like receptor 4 (TLR4) were detected by qRT-PCR; and phosphorylation levels of p38 and p65 were analysed by Western blot.

Results

Histopathological examination and examination of ALT and AST confirmed that MDHB is a low toxicity drug that can resist d-galN/LPS-induced ALF; MDHB can effectively reduce high transcription and expression of TNF-α, IL-1β, IL-6 and TLR4 in d-galN/LPS-induced ALF; and Western blot showed that MDHB could down-regulate the expression of bax, up-regulate the expression of bcl-xl and bcl-2, and inhibit the phosphorylation of p38 and p65.

Conclusions

Methyl 3,4-dihydroxybenzoate can effectively resist d-galN/LPS-induced acute liver failure, which is related to the inhibition of inflammation and apoptosis.

Stress of Strains: Inbred Mice in Liver Research

Inbred mice are the most popular animals used for in vivo liver research. These mice are genetically defined, readily available, less expensive to maintain than larger animals, and enjoy a broad array of commercial reagents for scientific characterization. C57BL/6 mice are the most commonly used strain. However, other strains discussed, including BALB/c, C3H, A/J, and FVB/N, may be better suited to a particular disease model or line of investigation. Understanding the phenotypes of different inbred mouse strains facilitates informed decision making during experimental design. Model systems influenced by strain-dependent phenotype include tissue regeneration, drug-induced liver injury (DILI; e.g., acetaminophen), fibrosis (e.g., carbon tetrachloride, CCl₄), Fas-induced apoptosis, cholestasis, alcohol-induced liver disease and cirrhosis, nonalcoholic fatty liver disease and steatohepatitis (NAFLD/NASH), and hepatocellular carcinoma (HCC). Thoughtful consideration of the strengths and weaknesses of each inbred strain in a given model system will lead to more robust data and a clearer understanding of translational relevance to human liver disease.

Identification of urate hydroperoxide in neutrophils: A novel pro-oxidant generated in inflammatory conditions

Uric acid is the final product of purine metabolism in humans and is considered to be quantitatively the main antioxidant in plasma. In vitro studies showed that the oxidation of uric acid by peroxidases, in presence of superoxide, generates urate free radical and urate hydroperoxide. Urate hydroperoxide is a strong oxidant and might be a relevant intermediate in inflammatory conditions. However, the identification of urate hydroperoxide in cells and biological samples has been a challenge due to its high reactivity. By using mass spectrometry, we undoubtedly demonstrated the formation of urate hydroperoxide and its corresponding alcohol, hydroxyisourate during the respiratory burst in peripheral blood neutrophils and in human leukemic cells differentiated in neutrophils (dHL-60). The respiratory burst was induced by phorbol myristate acetate (PMA) and greatly increased oxygen consumption and superoxide production. Both oxygen consumption and superoxide production were further augmented by incubation with uric acid. Conversely, uric acid significantly decreased the levels of HOCl, probably because of the competition with chloride by the catalysis of myeloperoxidase. In spite of the decrease in HOCl, the overall oxidative status, measured by GSH/GSSG ratio, was augmented in the presence of uric acid. In summary, the present results support the formation of urate hydroperoxide, a novel oxidant in neutrophils oxidative burst. Urate hydroperoxide is a strong oxidant and alters the redox balance toward a pro-oxidative environment. The production of urate hydroperoxide in inflammatory conditions could explain, at least in part, the harmful effect associated to uric acid.

Redox Regulation and Noncoding RNAs

SIGNIFICANCE

RNA is a heterogeneous class of molecules with the minority being protein coding. Noncoding RNAs (ncRNAs) are involved in translation and epigenetic control mechanisms of gene expression. Recent Advances: In recent years, the number of identified ncRNAs has dramatically increased and it is now clear that ncRNAs provide a complex layer of differential gene expression control.

CRITICAL ISSUES

NcRNAs exhibit interplay with redox regulation. Redox regulation alters the expression of ncRNAs; conversely, ncRNAs alter the expression of generator and effector systems of redox regulation in a complex manner, which will be the focus of this review article.

FUTURE DIRECTIONS

Understanding the role of ncRNA in redox control will lead to the development of new strategies to alter redox programs. Given that many ncRNAs (particularly microRNAs [miRNAs]) change large gene sets, these molecules are attractive drug candidates; already, now miRNAs can be targeted in patients. Therefore, the development of ncRNA therapies focusing on these molecules is an attractive future strategy. Antioxid. Redox Signal. 29, 793-812.

Cell Death Pathways: a Novel Therapeutic Approach for Neuroscientists

In the first part, the following mechanisms involved in different forms of cell death are considered, with a view to identifying potential therapeutic targets: tumour necrosis factor receptors (TNFRs) and their engagement by tumour necrosis factor-alpha (TNF-α); poly [ADP-ribose] polymerase (PARP)-1 cleavage; the apoptosis signalling kinase (ASK)-c-Jun N-terminal kinase (JNK) axis; lysosomal permeability; activation of programmed necrotic cell death; oxidative stress, caspase-3 inhibition and parthanatos; activation of inflammasomes by reactive oxygen species and the development of pyroptosis; oxidative stress, calcium dyshomeostasis and iron in the development of lysosomal-mediated necrosis and lysosomal membrane permeability; and oxidative stress, lipid peroxidation, iron dyshomeostasis and ferroptosis. In the second part, there is a consideration of the role of lethal and sub-lethal activation of these pathways in the pathogenesis and pathophysiology of neurodegenerative and neuroprogressive disorders, with particular reference to the TNF-α-TNFR signalling axis; dysregulation of ASK-1-JNK signalling; prolonged or chronic PARP-1 activation; the role of pyroptosis and chronic inflammasome activation; and the roles of lysosomal permeabilisation, necroptosis and ferroptosis. Finally, it is suggested that, in addition to targeting oxidative stress and inflammatory processes generally, neuropsychiatric disorders may respond to therapeutic targeting of TNF-α, PARP-1, the Nod-like receptor NLRP3 inflammasome and the necrosomal molecular switch receptor-interacting protein kinase-3, since their widespread activation can drive and/or exacerbate peripheral inflammation and neuroinflammation even in the absence of cell death. To this end, the use is proposed of a combination of the tetracycline derivative minocycline and N-acetylcysteine as adjunctive treatment for a range of neuropsychiatric disorders.

Wound Healing and Omega-6 Fatty Acids: From Inflammation to Repair

Wound healing is an evolutionarily conserved process that is essential for species survival. Wound healing involves a series of biochemical and cellular events that are tightly controlled, divided into 3 concomitant and overlapping phases: inflammation, proliferation, and remodelling. Poor wound healing or a chronic wound represents a silent epidemic that affects billions of people worldwide. Considering the involvement of immune cells in its resolution, recent studies are focused on investigating the roles of immune nutrients such as amino acids, minerals, and fatty acids on wound healing. Among the fatty acids, much attention has been given to omega-6 (ω-6) fatty acids since they can modulate cell migration and proliferation, phagocytic capacity, and production of inflammatory mediators. The present review summarizes current knowledge about the role of ω-6 fatty acids in the wound healing context.

The novel piperazine-containing compound LQFM018: Necroptosis cell death mechanisms, dopamine D4 receptor binding and toxicological assessment

Piperazine is a promising scaffold for drug development due to its broad spectrum of biological activities. Based on this, the new piperazine-containing compound LQFM018 (2) [ethyl 4-((1-(4-chlorophenyl)-1H-pyrazol-4-yl)methyl)piperazine-1-carboxylate] was synthetized and some biological activities investigated. In this work, we described its ability to bind aminergic receptors, antiproliferative effects as well as the LQFM018 (2)-triggered cell death mechanisms, in K562 leukemic cells, by flow cytometric analyses. Furthermore, acute oral systemic toxicity and potential myelotoxicity assessments of LQFM018 (2) were carried out. LQFM018 (2) was originally obtained by molecular simplification from LASSBio579 (1), an analogue compound of clozapine, with 33% of global yield. Binding profile assay to aminergic receptors showed that LQFM018 (2) has affinity for the dopamine D₄ receptor (K_i = 0.26 μM). Moreover, it showed cytotoxicity in K562 cells, in a concentration and time-dependent manner; IC₅₀ values obtained were 399, 242 and 119 μM for trypan blue assay and 427, 259 and 50 μM for MTT method at 24, 48 or 72 h, respectively. This compound (427 μM) also promoted increase in LDH release and cell cycle arrest in G2/M phase. Furthermore, it triggered necrotic morphologies in K562 cells associated with intense cell membrane rupture as confirmed by Annexin V/propidium iodide double-staining. LQFM018 (2) also triggered mitochondrial disturb through loss of ΔΨm associated with increase of ROS production. No significant accumulation of cytosolic cytochrome c was verified in treated cells. Furthermore, it was verified an increase of expression of TNF-R1 and mRNA levels of CYLD with no involviment in caspase-3 and -8 activation and NF-κB in K562 cells. LQFM018 (2) showed in vitro myelotoxicity potential, but it was orally well tolerated and classified as UN GHS category 5 (LD₅₀ > 2000-5000 mg/Kg). Thus, LQFM018 (2) seems to have a non-selective action considering hematopoietic cells. In conclusion, it is suggested LQFM018 (2) promotes cell death in K562 cells via necroptotic signaling, probably with involvement of dopamine D₄ receptor. These findings open new perspectives in cancer therapy by use of necroptosis inducing agents as a strategy of reverse cancer cell chemoresistance.

Uric acid disrupts hypochlorous acid production and the bactericidal activity of HL-60 cells

Uric acid is the end product of purine metabolism in humans and is an alternative physiological substrate for myeloperoxidase. Oxidation of uric acid by this enzyme generates uric acid free radical and urate hydroperoxide, a strong oxidant and potentially bactericide agent. In this study, we investigated whether the oxidation of uric acid and production of urate hydroperoxide would affect the killing activity of HL-60 cells differentiated into neutrophil-like cells (dHL-60) against a highly virulent strain (PA14) of the opportunistic pathogen Pseudomonas aeruginosa. While bacterial cell counts decrease due to dHL-60 killing, incubation with uric acid inhibits this activity, also decreasing the release of the inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF- α). In a myeloperoxidase/Cl^-/H₂O₂ cell-free system, uric acid inhibited the production of HOCl and bacterial killing. Fluorescence microscopy showed that uric acid also decreased the levels of HOCl produced by dHL-60 cells, while significantly increased superoxide production. Uric acid did not alter the overall oxidative status of dHL-60 cells as measured by the ratio of reduced (GSH) and oxidized (GSSG) glutathione. Our data show that uric acid impairs the killing activity of dHL-60 cells likely by competing with chloride by myeloperoxidase catalysis, decreasing HOCl production. Despite diminishing HOCl, uric acid probably stimulates the formation of other oxidants, maintaining the overall oxidative status of the cells. Altogether, our results demonstrated that HOCl is, indeed, the main relevant oxidant against bacteria and deviation of myeloperoxidase activity to produce other oxidants hampers dHL-60 killing activity.

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Uric acid decreased microbicide activity and release of cytokines by dHL-60 cells.

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Uric acid decreased HOCl in cells and in the myeloperoxidase/Cl^-/H₂O₂ system.

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Uric acid induces a pro-oxidant redox imbalance.

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HOCl is crucial for Pseudomonas aeruginosa killing by dHL-60.