Microbial-transcriptome integrative analysis of heat stress effects on amino acid metabolism and lipid peroxidation in poultry jejunum

Despite the significant threat of heat stress to livestock animals, only a few studies have considered the potential relationship between broiler chickens and their microbiota. Therefore, this study examined microbial modifications, transcriptional changes and host-microbiome interactions using a predicted metabolome data-based approach to understand the impact of heat stress on poultry. After the analysis, the host functional enrichment analysis revealed that pathways related to lipid and protein metabolism were elevated under heat stress conditions. In contrast, pathways related to the cell cycle were suppressed under normal environmental temperatures. In line with the transcriptome analysis, the microbial analysis results indicate that taxonomic changes affect lipid degradation. Heat stress engendered statistically significant difference in the abundance of 11 microorganisms, including Bacteroides and Peptostreptococcacea. Together, integrative approach analysis suggests that microbiota-induced metabolites affect host fatty acid peroxidation metabolism, which is correlated with the gene families of Acyl-CoA dehydrogenase long chain (ACADL), Acyl-CoA Oxidase (ACOX) and Acetyl-CoA Acyltransferase (ACAA). This integrated approach provides novel insights into heat stress problems and identifies potential biomarkers associated with heat stress.

SARS-CoV-2 deregulates the vascular and immune functions of brain pericytes via Spike protein

Coronavirus disease 19 (COVID-19) is a respiratory illness caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). COVID-19 pathogenesis causes vascular-mediated neurological disorders via elusive mechanisms. SARS-CoV-2 infects host cells via the binding of viral Spike (S) protein to transmembrane receptor, angiotensin-converting enzyme 2 (ACE2). Although brain pericytes were recently shown to abundantly express ACE2 at the neurovascular interface, their response to SARS-CoV-2 S protein is still to be elucidated. Using cell-based assays, we found that ACE2 expression in human brain vascular pericytes was increased upon S protein exposure. Pericytes exposed to S protein underwent profound phenotypic changes associated with an elongated and contracted morphology accompanied with an enhanced expression of contractile and myofibrogenic proteins, such as α-smooth muscle actin (α-SMA), fibronectin, collagen I, and neurogenic locus notch homolog protein-3 (NOTCH3). On the functional level, S protein exposure promoted the acquisition of calcium (Ca2+) signature of contractile ensheathing pericytes characterized by highly regular oscillatory Ca2+ fluctuations. Furthermore, S protein induced lipid peroxidation, oxidative and nitrosative stress in pericytes as well as triggered an immune reaction translated by activation of nuclear factor-kappa-B (NF-κB) signaling pathway, which was potentiated by hypoxia, a condition associated with vascular comorbidities that exacerbate COVID-19 pathogenesis. S protein exposure combined to hypoxia enhanced the production of pro-inflammatory cytokines involved in immune cell activation and trafficking, namely macrophage migration inhibitory factor (MIF). Using transgenic mice expressing the human ACE2 that recognizes S protein, we observed that the intranasal infection with SARS-CoV-2 rapidly induced hypoxic/ischemic-like pericyte reactivity in the brain of transgenic mice, accompanied with an increased vascular expression of ACE2. Moreover, we found that SARS-CoV-2 S protein accumulated in the intranasal cavity reached the brain of mice in which the nasal mucosa is deregulated. Collectively, these findings suggest that SARS-CoV-2 S protein impairs the vascular and immune regulatory functions of brain pericytes, which may account for vascular-mediated brain damage. Our study provides a better understanding for the mechanisms underlying cerebrovascular disorders in COVID-19, paving the way to develop new therapeutic interventions.

TRP Channels as Sensors of Aldehyde and Oxidative Stress

The transient receptor potential (TRP) cation channel superfamily comprises more than 50 channels that play crucial roles in physiological processes. TRP channels are responsive to several exogenous and endogenous biomolecules, with aldehydes emerging as a TRP channel trigger contributing to a cellular cascade that can lead to disease pathophysiology. The body is not only exposed to exogenous aldehydes via tobacco products or alcoholic beverages, but also to endogenous aldehydes triggered by lipid peroxidation. In response to lipid peroxidation from inflammation or organ injury, polyunsaturated fatty acids undergo lipid peroxidation to aldehydes, such as 4-hydroxynonenal. Reactive aldehydes activate TRP channels via aldehyde-induced protein adducts, leading to the release of pro-inflammatory mediators driving the pathophysiology caused by cellular injury, including inflammatory pain and organ reperfusion injury. Recent studies have outlined how aldehyde dehydrogenase 2 protects against aldehyde toxicity through the clearance of toxic aldehydes, indicating that targeting the endogenous aldehyde metabolism may represent a novel treatment strategy. An addition approach can involve targeting specific TRP channel regions to limit the triggering of a cellular cascade induced by aldehydes. In this review, we provide a comprehensive summary of aldehydes, TRP channels, and their interactions, as well as their role in pathological conditions and the different therapeutical treatment options.

Comparative transcriptome analyses revealed different heat stress responses in pigeonpea (Cajanus cajan) and its crop wild relatives

Comparative transcriptome analyses accompanied by biochemical assays revealed high variability in heat stress response in Cajanus species. Among the studied species, C. scarabaeoides was the most thermotolerant followed by C. cajanifolius, C. cajan, and C. acutifolius. Pigeonpea is one of the climate-resilient grain legumes. Though the optimum temperature for cultivated pigeonpea is ~ 25-35 °C, its wild relatives grow in temperatures ranging between 18 and 45 °C. To gain insight into molecular mechanisms responsible for the heat stress tolerance in pigeonpea, we conducted time-series transcriptome analysis of one pigeonpea cultivar (Cajanus cajan) and two wild relatives, Cajanus acutifolius, and Cajanus scarabaeoides subjected to heat stress at 42 ± 2 ºC for 30 min and 3 h. A total of 9521, 12,447, and 5282 identified transcripts were differentially expressed in C. cajan, C. acutifolius, and C. scarabaeoides, respectively. In this study, we observed that a significant number of genes undergo alternative splicing in a species-specific pattern during heat stress. Gene expression profiling analysis, histochemical assay, chlorophyll content, and electrolyte leakage assay showed that C. scarabaeoides has adaptive features for heat stress tolerance. The gene set enrichment analyses of differentially expressed genes in these Cajanus species during heat stress revealed that oxidoreductase activity, transcription factor activity, oxygen-evolving complex, photosystem-II, thylakoid, phenylpropanoid biosynthetic process, secondary metabolic process, and flavonoid biosynthetic process were highly affected. The histochemical assay showed more lipid peroxidation in C. acutifolius compared to other Cajanus species inferring the presence of higher quantities of polyunsaturated fatty acids in the plasma membrane which might have led to severe damage of membrane-bound organelles like chloroplast, and high electrolyte leakage during heat stress. This study paves the way for the identification of candidate genes, which can be useful for the development of thermo-tolerant pigeonpea cultivars.

Differences in cell death in methionine versus cysteine depletion

Restriction of the sulfur amino acids methionine and cysteine has recently been proposed as potential adjuvant therapy in cancer. While cysteine depletion has been associated with ferroptotic cell death, methionine depletion has not. We hypothesized that comparing the response of melanoma cell lines to depletion of the amino acids methionine and cysteine would give us insight into the critical role in cancer of these two closely related amino acids. We analyzed the response to three conditions: methionine depletion, methionine replacement with homocysteine, and cysteine depletion. In cancer cells, the transcription factor ATF4 was induced by all three tested conditions. The replacement of methionine with homocysteine produced a strong ferroptotic gene signature. We also detected an activation of the NRF2 antioxidant pathway by both methionine and cysteine depletion. Total glutathione levels were decreased by 42% in melanoma cells grown without methionine, and by 95% in cells grown without cysteine. Lipid peroxidation was increased in cells grown without cysteine, but not in cells grown without methionine. Despite the large degree of overlap in gene expression between methionine and cysteine depletion, methionine depletion and replacement of methionine with homocysteine was associated with apoptosis while cysteine depletion was associated with ferroptosis. Glutamine depletion produced comparable gene expression patterns and was associated with a 28% decrease in glutathione. Apoptosis was detected in these cells. In this experiment, a strong ATF4-driven ferroptotic gene signature was insufficient to induce ferroptosis without a concomitant profound decrease in glutathione levels.

Ferroptosis: mechanisms and links with diseases

Ferroptosis is an iron-dependent cell death, which is different from apoptosis, necrosis, autophagy, and other forms of cell death. The process of ferroptotic cell death is defined by the accumulation of lethal lipid species derived from the peroxidation of lipids, which can be prevented by iron chelators (e.g., deferiprone, deferoxamine) and small lipophilic antioxidants (e.g., ferrostatin, liproxstatin). This review summarizes current knowledge about the regulatory mechanism of ferroptosis and its association with several pathways, including iron, lipid, and cysteine metabolism. We have further discussed the contribution of ferroptosis to the pathogenesis of several diseases such as cancer, ischemia/reperfusion, and various neurodegenerative diseases (e.g., Alzheimer's disease and Parkinson's disease), and evaluated the therapeutic applications of ferroptosis inhibitors in clinics.

The comparison of pro- and antioxidative parameters in plasma and placental tissues during early phase of placental development in cows

Physiological balance between pro- and antioxidative processes is crucial for placentation and further development of fetus and placenta. Parameters of pro- and antioxidative profile may serve as markers of proper course of pregnancy. The aim of study was to assess whether the balance between pro- and antioxidative parameters during placentation phase in bovine placenta is maintained. Placental and blood samples were collected from healthy, HF, pregnant (2nd-3rd month) cows (n = 8) in slaughterhouse and in farm, respectively. Formylokinurenine and bityrosine content were measured spectrofluorimetrically in blood plasma and tissue homogenates while metabolites of lipid peroxidation, total antioxidant capacity, SH groups and activity of antioxidative enzymes (glutathione peroxidase and superoxide dismutase) were determined in examined tissues by spectrophotometry. Western blotting was used to confirm the presence of enzymatic proteins in placenta. Results: Local profile in tissues was more pronounced than general profile in blood plasma. Activities of antioxidative enzymes were significantly (p < 0.05) higher in 2nd compared to 3rd month of pregnancy in maternal part of placenta while prooxidant parameters showed opposite relationship. Obtained results showed significant differences when compared to data from non-pregnant animals or time of parturition. Further studies are necessary for elucidation of placentation phase in cows.

An Overview of the Ferroptosis Hallmarks in Friedreich's Ataxia

BACKGROUND

Friedreich's ataxia (FRDA) is a neurodegenerative disease characterized by early mortality due to hypertrophic cardiomyopathy. FRDA is caused by reduced levels of frataxin (FXN), a mitochondrial protein involved in the synthesis of iron-sulphur clusters, leading to iron accumulation at the mitochondrial level, uncontrolled production of reactive oxygen species and lipid peroxidation. These features are also common to ferroptosis, an iron-mediated type of cell death triggered by accumulation of lipoperoxides with distinct morphological and molecular characteristics with respect to other known cell deaths.

SCOPE OF REVIEW

Even though ferroptosis has been associated with various neurodegenerative diseases including FRDA, the mechanisms leading to disease onset/progression have not been demonstrated yet. We describe the molecular alterations occurring in FRDA that overlap with those characterizing ferroptosis.

MAJOR CONCLUSIONS

The study of ferroptotic pathways is necessary for the understanding of FRDA pathogenesis, and anti-ferroptotic drugs could be envisaged as therapeutic strategies to cure FRDA.

Distinct TP53 Mutation Types Exhibit Increased Sensitivity to Ferroptosis Independently of Changes in Iron Regulatory Protein Activity

The tumor suppressor gene TP53 is the most commonly mutated gene in human cancer. In addition to loss of tumor suppressor functions, mutations in TP53 promote cancer progression by altering cellular iron acquisition and metabolism. A newly identified role for TP53 in the coordination of iron homeostasis and cancer cell survival lies in the ability for TP53 to protect against ferroptosis, a form of iron-mediated cell death. The purpose of this study was to determine the extent to which TP53 mutation status affects the cellular response to ferroptosis induction. Using H1299 cells, which are null for TP53, we generated cell lines expressing either a tetracycline inducible wild-type (WT) TP53 gene, or a representative mutated TP53 gene from six exemplary “hotspot” mutations in the DNA binding domain (R273H, R248Q, R282W, R175H, G245S, and R249S). TP53 mutants (R273H, R248Q, R175H, G245S, and R249S) exhibited increased sensitivity ferroptosis compared to cells expressing WT TP53. As iron-mediated lipid peroxidation is critical for ferroptosis induction, we hypothesized that iron acquisition pathways would be upregulated in mutant TP53-expressing cells. However, only cells expressing the R248Q, R175H, and G245S TP53 mutation types exhibited statistically significant increases in spontaneous iron regulatory protein (IRP) RNA binding activity following ferroptosis activation. Moreover, changes in the expression of downstream IRP targets were inconsistent with the observed differences in sensitivity to ferroptosis. These findings reveal that canonical iron regulatory pathways are bypassed during ferroptotic cell death. These results also indicate that induction of ferroptosis may be an effective therapeutic approach for tumor cells expressing distinct TP53 mutation types.

Genotoxicity and oxidative stress in Caiman latirostris hatchlings exposed to pesticide formulations and their mixtures during incubation period

Agricultural expansion and the consequent use of pesticides lead to the loss and fragmentation of natural habitats of several wild species. Then, many species are inevitably exposed to a wide amount of pesticide formulations. Glyphosate (GLY)-based formulations are the most used herbicide, whereas two of the most employed insecticides are chlorpyrifos (CPF) and cypermethrin (CYP). The aim of this study was to evaluate genotoxicity, oxidative damage, and the modulation of antioxidants defenses in peripheral blood of Caiman latirostris after embryonic exposure to pesticide formulations and their mixtures. Pesticides concentrations employed were equivalent to those recommended in agricultural practices for application in soybean crops and a half of them: GLY: 2% and 1%; CYP: 0.12% and 0.06%; CPF: 0.8% and 0.4%. Two similar experiments (E1 and E2) were carried out in consecutive years, where C. latirostris eggs were exposed to pesticide formulations separately and in different mixtures through application on the incubation material. After hatching, blood samples were taken and genotoxicity and oxidative stress was evaluated through the micronucleus (MN) test, the modified comet assay, the lipid peroxidation (LPO) levels and the activities of catalase (CAT) and superoxide dismutase (SOD) antioxidant enzymes. The results indicated the presence of DNA damage, oxidation of purines and pyrimidines, and increased frequency of micronucleus (FMN) in the case of GLY, CYP, and CPF formulations exposure, as well as in all the mixtures tested, with respect to the control groups. Specifically, the results observed for the mixtures would indicate independent action or antagonism of the components for DNA damage and base oxidation (purines and pyrimidines) and a possible potentiation interaction for the FMN in two binary mixtures. However, there were not differences regarding lipid peroxidation, the activity of antioxidant enzymes and growth parameters. This study proved that the use of pesticide formulations at concentrations used in the field generate deleterious genetic effects on this species, then, exposure to them could threaten its survival and health status.

Lack of Dose- and Time-Dependent Effects of Aflatoxin B1 on Gene Expression and Enzymes Associated with Lipid Peroxidation and the Glutathione Redox System in Chicken

Effects of aflatoxin B1 (AFB1) on lipid peroxidation and glutathione system were investigated in chicken liver. In a three-week feeding trial, different doses (<1.0 μg/kg (control diet), 17.0 µg (diet A1), 92.0 µg (diet A2), and 182.0 µg (diet A3) AFB1 kg/feed) were used. Markers of lipid peroxidation, conjugated dienes and trienes showed higher values in A3, while amounts of thiobarbituric acid reactive substances were increased in the A1 group at day 21. Glutathione content was lower at day 14 in Group A2. Glutathione peroxidase 4 activity was increased at days 7 and 21 in the A3 group but reduced in the A2 and A3 groups at day 14. The GPX4 gene was downregulated at day 7 in the A2 group, but overregulated at days 14 and 21, and at day 14 in the A3 group. GSS was downregulated at day 14 in the A1 group but overregulated at day 21 in A1 and A2 groups. GSR was downregulated at days 7 and 21 in all treatment groups, but on day 14, induction was observed in the A3 group. The results indicated that AFB1 did not induce dose- or time-dependent effects on the glutathione redox system and its encoding genes at the dose range used, which means that oxidative stress is not the primary effect of AFB1 toxicity.

Oxidation-Specific Epitopes in Non-Alcoholic Fatty Liver Disease

An improper balance between the production and elimination of intracellular reactive oxygen species causes increased oxidative stress. Consequently, DNA, RNA, proteins, and lipids are irreversibly damaged, leading to molecular modifications that disrupt normal function. In particular, the peroxidation of lipids in membranes or lipoproteins alters lipid function and promotes formation of neo-epitopes, such as oxidation-specific epitopes (OSEs), which are found to be present on (lipo)proteins, dying cells, and extracellular vesicles. Accumulation of OSEs and recognition of OSEs by designated pattern recognition receptors on immune cells or soluble effectors can contribute to the development of chronic inflammatory diseases. In line, recent studies highlight the involvement of modified lipids and OSEs in different stages of the spectrum of non-alcoholic fatty liver disease (NAFLD), including inflammatory non-alcoholic steatohepatitis (NASH), fibrosis, and hepatocellular carcinoma. Targeting lipid peroxidation products shows high potential in the search for novel, better therapeutic strategies for NASH.

Detection of HNE Modification of Proteins in Aging Mouse Tissues: A Western Blot-Based Approach

4-Hydroxenonenal (HNE) is one of the major α,β-unsaturated aldehyde products of lipid peroxidation. HNE can form conjugates with macromolecules, including protein, and thereby alter their function. HNE and its conjugation with proteins are increased in aging and age-related diseases. To elucidate how HNE is involved in these aging-related pathophysiological changes, it is necessary to assess HNE modification of proteins. Here a simple and convenient Western-blot based method is presented to detect HNE modification of proteins in tissues of aging mice.

Increase in omega-6 and decrease in omega-3 polyunsaturated fatty acid oxidation elevates the risk of exudative AMD development in adults with Chinese diet

Appropriate diet is essential for the regulation of age-related macular degeneration (AMD). In particular the type of dietary polyunsaturated fatty acids (PUFA) and poor antioxidant status including carotenoid levels concomitantly contribute to AMD risk. Build-up of oxidative stress in AMD induces PUFA oxidation, and a mix of lipid oxidation products (LOPs) are generated. However, LOPs are not comprehensively evaluated in AMD. LOPs are considered biomarkers of oxidative stress but also contributes to inflammatory response. In this cross-sectional case-control study, plasma omega-6/omega-3 PUFA ratios and antioxidant status (glutathione, superoxide dismutase and catalase), and plasma and urinary LOPs (41 types) were determined to evaluate its odds-ratio in the risk of developing exudative AMD (n = 99) compared to age-gender-matched healthy controls (n = 198) in adults with Chinese diet. The odds ratio of developing exudative AMD increased with LOPs from omega-6 PUFA and decreased from those of omega-3 PUFA. These observations were associated with a high plasma omega-6/omega-3 PUFA ratio and low carotenoid levels. In short, poor PUFA and antioxidant status increased the production of omega-6 PUFA LOPs such as dihomo-isoprostane and dihomo-isofuran, and lowered omega-3 PUFA LOPs such as neuroprostanes due to the high omega-6/omega-3 PUFA ratios; they were also correlated to the risk of AMD development. These findings indicate the generation of specific LOPs is associated with the development of exudative AMD.

Curcumin mitigates mancozeb-induced hepatotoxicity and genotoxicity in rats

Mancozeb (MZ) is a widely used ethylene-bis-dithiocarbamate fungicide in agriculture causing hepatoxic and genotoxic effects in rats. Curcumin (CUR) has various pharmacological effects including antioxidant and anti-inflammatory properties. This study investigated the efficacy of CUR in mitigating MZ-induced hepatotoxicity and genotoxicity in rats. Twenty-four male rats were divided into four equal groups; group I (control) was given carboxymethyl cellulose, group II was orally administered CUR (100 mg/kg b.wt), group III was gavaged with MZ (750 mg/kg b.wt), and group IV was co-treated with MZ and CUR at the same doses daily for 10 weeks. As a result, the concurrent treatment with CUR and MZ minimized the increased levels of liver function markers in serum, lipid peroxidation, pro-inflammatory mediators and DNA damage parameters in liver. In addition, CUR administration improved the depleted markers of hepatic antioxidant status in MZ-treated rats. Moreover, CUR protected the liver against the histological alterations elicited by MZ exposure and also, reduced the immunopositive reactivity of pro-apoptotic p53 in cytoplasm of hepatocytes. The present findings suggest that CUR exerts a significant protective effect against MZ-induced hepatotoxicity and genotoxicity.

FSP1 is a glutathione-independent ferroptosis suppressor

Ferroptosis is an iron-dependent form of necrotic cell death marked by oxidative damage to phospholipids1,2. To date, ferroptosis has been thought to be controlled only by the phospholipid hydroperoxide-reducing enzyme glutathione peroxidase 4 (GPX4)3,4 and radical-trapping antioxidants5,6. However, elucidation of the factors that underlie the sensitivity of a given cell type to ferroptosis7 is crucial to understand the pathophysiological role of ferroptosis and how it may be exploited for the treatment of cancer. Although metabolic constraints8 and phospholipid composition9,10 contribute to ferroptosis sensitivity, no cell-autonomous mechanisms have been identified that account for the resistance of cells to ferroptosis. Here we used an expression cloning approach to identify genes in human cancer cells that are able to complement the loss of GPX4. We found that the flavoprotein apoptosis-inducing factor mitochondria-associated 2 (AIFM2) is a previously unrecognized anti-ferroptotic gene. AIFM2, which we renamed ferroptosis suppressor protein 1 (FSP1) and which was initially described as a pro-apoptotic gene11, confers protection against ferroptosis elicited by GPX4 deletion. We further demonstrate that the suppression of ferroptosis by FSP1 is mediated by ubiquinone (also known as coenzyme Q10, CoQ10): the reduced form, ubiquinol, traps lipid peroxyl radicals that mediate lipid peroxidation, whereas FSP1 catalyses the regeneration of CoQ10 using NAD(P)H. Pharmacological targeting of FSP1 strongly synergizes with GPX4 inhibitors to trigger ferroptosis in a number of cancer entities. In conclusion, the FSP1-CoQ10-NAD(P)H pathway exists as a stand-alone parallel system, which co-operates with GPX4 and glutathione to suppress phospholipid peroxidation and ferroptosis.

Antioxidant, physiological and biochemical responses of drought susceptible and drought tolerant mustard (Brassica juncea L) genotypes to rhizobacterial inoculation under water deficit stress

Response of drought susceptible (DS) genotype Pusa Karishma LES-39 and drought tolerant (DT) mustard genotype NPJ-124, to rhizobacterial inoculation under water deficit stress, was compared in the present study to determine the influence of inoculants on biochemical and physiological attributes of these two different genotypes. Inoculation was observed to improve root and shoot dry weight in both the genotypes, although better results were observed in the DS genotype. There was variation in the response of the two genotypes to rhizobacterial inoculation, under water deficit stress. Significant improvement in most of the physiological and biochemical parameters including antioxidative enzyme activities of the DS genotype; with concomitant decrease in starch content, accumulation of H₂O₂ and lipid peroxidation upon inoculation of rhizobacteria was observed. In contrast, there was improvement in only few physiological and biochemical parameters in the DT genotype in response to inoculation with rhizobacteria. There was significant increase in catalase enzyme activity along with concomitant decrease in lipid peroxidation. Thus, drought susceptibility of the mustard genotypes, NPJ-124 and Pusa Karishma LES-39, determined their physiological, biochemical and antioxidative responses to rhizobacterial inoculation under water deficit stress. Expression of drought stress responsive genes belonging to ABA-dependent (RD20 and RD26) and ABA-independent (DREB2 and DREB1-2) pathways was studied in the DS genotype. Expression of DREB2 and DREB1-2 genes was considerably enhanced due to inoculation under water deficit stress; indicating that in Bacillus-mediated priming for drought stress tolerance, in this genotype, ABA-independent pathway probably played key role in enhancing tolerance to drought stress.

P53-induced reduction of lipid peroxidation supports brain microvascular endothelium integrity

Dysregulation of the blood brain barrier due to oxidative stress causes neurological disorders, such as Alzheimer's and Parkinson's disease. We employed brain microvascular endothelial cells; to investigate the effects of P53 towards the lipid oxidation of the BBB. P53 reduction by LPS, siRNA for P53 and Pifithrin increased the expression levels of malondialdehyde, a marker of oxidative stress and lipid peroxidation. Furthermore, P53 suppression impaired the permeability of the BBB monolayers. In contrast, P53 induction by Nutlin and Hsp90 inhibitor AUY922 enhanced the BBB function. In conclusion, P53 supports BBB integrity, at least in part, by reducing lipid peroxidation.

Plin5 deficiency exacerbates pressure overload-induced cardiac hypertrophy and heart failure by enhancing myocardial fatty acid oxidation and oxidative stress

While cardiac hypertrophy and heart failure are accompanied by significant alterations in energy metabolism, more than 50-70% of energy is obtained from fatty acid β-oxidation (FAO) in adult hearts under physiological conditions. Plin5 is involved in the metabolism of lipid droplets (LDs) and is highly abundant in oxidative tissues including heart, liver and skeletal muscle. Plin5 protects the storage of triglyceride (TG) in LDs by inhibiting lipolysis, thereby suppressing excess FAO and preventing excessive oxidative stress in the heart. In this study, we investigated the roles of Plin5 in cardiac hypertrophy and heart failure in mice treated with transverse aortic constriction (TAC). The results indicated that Plin5 deficiency aggravated myocardial hypertrophy in the TAC-treated mice and exacerbated the TAC-induced heart failure. We also found that Plin5 deficiency reduced the cardiac lipid accumulation and upregulated the levels of PPARα and PGC-1α, which stimulate mitochondrial proliferation. Moreover, Plin5 deficiency aggravated the TAC-induced oxidative stress. We consistently found that Plin5 knockdown disrupted TG storage and elevated FAO and lipolysis in H9C2 rat cardiomyocytes. In addition, Plin5 knockdown also provoked mitochondrial proliferation and lipotoxic injury in H9C2 cells. In conclusion, Plin5 deficiency increases myocardial lipolysis, elevates FAO and oxidative burden, and thereby exacerbates cardiac hypertrophy and heart failure in TAC-treated mice.

Clockophagy is a novel selective autophagy process favoring ferroptosis

Ferroptosis is a form of nonapoptotic regulated cell death driven by iron-dependent lipid peroxidation. Autophagy involves a lysosomal degradation pathway that can either promote or impede cell death. A high level of autophagy has been associated with ferroptosis, but the mechanisms underpinning this relationship are largely elusive. We characterize the contribution of autophagy to ferroptosis in human cancer cell lines and mouse tumor models. We show that "clockophagy," the selective degradation of the core circadian clock protein ARNTL by autophagy, is critical for ferroptosis. We identify SQSTM1 as a cargo receptor responsible for autophagic ARNTL degradation. ARNTL inhibits ferroptosis by repressing the transcription of Egln2, thus activating the prosurvival transcription factor HIF1A. Genetic or pharmacological interventions blocking ARNTL degradation or inhibiting EGLN2 activation diminished, whereas destabilizing HIF1A facilitated, ferroptotic tumor cell death. Thus, our findings reveal a new pathway, initiated by the autophagic removal of ARNTL, that facilitates ferroptosis induction.

Paraoxonase 1 (PON1) Q192R and L55M polymorphisms, lipid profile, lipid peroxidation and lipoprotein-a levels in Turkish patients with pregnancy-related disorders

The aim of this study was to investigate the role of PON1Q192R and L55M single nucleotide polymorphisms(SNPs) and its association with the maternal levels of lipid parameters in gestational diabetes mellitus(GDM) and preeclampsia(PE). Ninety-nine pregnant with GDM, 97 pregnant with PE and 98 healthy pregnant were included in the study. No statistically significant difference was observed in the alleles or in the genotypes frequencies of SNPs between groups. In GDM patients, total cholesterol was higher in MM genotype of L55M gene (p < .05); Lp(a) were lower in LM genotype of the gene compared to their respective control (p < .05). In PE, HDL-C levels were higher in LM genotype (p < .05); LDL-C levels were lower in MM genotype of the gene compared to their respective control (p < .05). In PE patients, malondialdehyde(MDA) were higher in QQ genotype compared to their respective control (p < .05). Triglyceride levels were higher in PE patients with QR genotype compared with GDM patients with QR genotype (p < .05). Our results indicated that lipid profiles, Lp(a) and MDA levels showed significant differences in GDM and PE pregnants. These findings support the importance of the lipid profile, oxidized lipid and Lp(a) in different genotypes of L55M and Q192R in Turkish pregnant women with PE/GDM suggesting their roles in etiopathogenesis in these pregnancy-related disorders.

The tumor suppressor protein p53 and the ferroptosis network

Ferroptosis is a form of lipid peroxidation-induced cell death that can be regulated in many ways, from altering the activity of antioxidant enzymes to the level of transcription factors. The p53 tumor suppressor is 'the guardian of the genome' that participates in the control of cell survival and division under various stresses. Beyond its effects on apoptosis, autophagy, and cell cycle, p53 also regulates ferroptosis either through a transcriptional or posttranslational mechanism. On one hand, p53 can enhance ferroptosis by inhibiting the expression of SLC7A11 (solute carrier family 7 member 11) or by enhancing that of SAT1 (spermidine/spermine N1-acetyltransferase 1) and GLS2 (glutaminase 2). On the other hand, p53 suppresses ferroptosis through the direct inhibition of DPP4 (dipeptidyl peptidase 4) activity or by the induction of CDKN1A/p21 (cyclin dependent kinase inhibitor 1 A) expression. Here, we review recent discoveries and emerging trends in the study of the ferroptosis network and highlight the context-dependent impact of p53 on ferroptosis and oxidative stress.

Role of GPX4 in ferroptosis and its pharmacological implication

Ferroptosis is a non-apoptotic form of cell death characterized by iron-dependent lipid peroxidation and metabolic constraints. Dependence on NADPH/H⁺, polyunsaturated fatty acid metabolism, and the mevalonate and glutaminolysis metabolic pathways have been implicated in this novel form of regulated necrotic cell death. Genetic studies performed in cells and mice established the selenoenzyme glutathione peroxidase (GPX4) as the key regulator of this form of cell death. Besides these genetic models, the identification of a series of small molecule ferroptosis-specific inhibitors and inducers have not only helped in the delineation of the molecular underpinnings of ferroptosis but they might also prove highly beneficial when tipping the balance between cell death inhibition and induction in the context of degenerative diseases and cancer, respectively. In the latter, the recent recognition that a subset of cancer cell lines including certain triple negative breast cancer cells and those of therapy-resistant high-mesenchymal cell state present a high dependence on this lipid make-up offers unprecedented opportunities to eradicate difficult to treat cancers. Due to the rapidly growing interest in this form of cell death, we provide an overview herein what we know about this field today and its future translational impact.

Melatonin Alleviates Copper Toxicity via Improving Copper Sequestration and ROS Scavenging in Cucumber

Melatonin plays an important role in stress tolerance in plants. In this study, exogenous melatonin significantly alleviated the dwarf phenotype and inhibited the decrease of plant fresh weight induced by excess copper (Cu2+). Our results indicated that melatonin alleviated Cu2+ toxicity by improving Cu2+ sequestration, carbon metabolism and ROS (reactive oxygen species) scavenging, rather than by influencing the Cu2+ uptake under excess Cu2+ conditions. Transcriptome analysis showed that melatonin broadly altered gene expression under Cu2+ stress. Melatonin increased the levels of glutathione and phytochelatin to chelate excess Cu2+ and promoted cell wall trapping, thus keeping more Cu2+ in the cell wall and vacuole. Melatonin inhibited ROS production and enhanced antioxidant systems at the transcriptional level and enzyme activities, thus building a line of defense in response to excess Cu2+. The distribution of nutrient elements was recovered by melatonin which was disturbed by Cu2+. In addition, melatonin activated carbon metabolism, especially glycolysis and the pentose phosphate pathway, to generate more ATP, an intermediate for biosynthesis. Taken together, melatonin alleviated Cu2+ toxicity in cucumber via multiple mechanisms. These results will help to resolve the toxic effects of Cu2+ stress on plant growth and development. These results can be used for new strategies to solve problems associated with Cu2+ stress.

Exogenous gibberellin weakens lipid breakdown by increasing soluble sugars levels in early germination of zanthoxylum seeds

Zanthoxylum is a precious medicinal woody plant with a very low seed germination rate in China. The gibberellin (GA) treatment extremely increased the germination rate of zanthoxylum seeds. Our previous transcriptome data showed that exogenous GA played a negative role in the expression levels of genes involved in lipid metabolism during imbibition. Our present data indicated that compared with the GA-treated seeds, the soluble sugars were more quickly consumed and lipid breakdown was prematurely and actively initiated in the water-treated seeds during the early germination. However, the application of sucrose could improve the germination of water-treated seeds and significantly inhibit lipid breakdown. Both the application of sucrose and exogenous GA could significantly reduce the catalytic activities of sugar-dependent 1 (SDP1) and isocitratelyase (ICL), the expressions of SDP1 and ICL genes, and decrease the products of lipid breakdown as well during the early germination. We suggested that exogenous GA might enhance starch hydrolysis by promoting the catalytic activity of ɑ-amylase to supplement metabolically consumed soluble sugars, thus the increased sugars levels would help to inhibit the lipid breakdown to mitigate oxidative damages in the early germination of zanthoxylum seeds. In the end, we summarized the possible molecular mechanism on the exogenous GA weakening lipid breakdown by increasing soluble sugars levels in the early germination of zanthoxylum seeds.

The development of the concept of ferroptosis

The term ferroptosis was coined in 2012 to describe an iron-dependent regulated form of cell death caused by the accumulation of lipid-based reactive oxygen species; this type of cell death was found to have molecular characteristics distinct from other forms of regulated cell death. Features of ferroptosis have been observed periodically over the last several decades, but these molecular features were not recognized as evidence of a distinct form of cell death until recently. Here, we describe the history of observations consistent with the current definition of ferroptosis, as well as the advances that contributed to the emergence of the concept of ferroptosis. We also discuss recent implications and applications of manipulations of the ferroptotic death pathway.

Iron catalysis of lipid peroxidation in ferroptosis: Regulated enzymatic or random free radical reaction?

Duality of iron as an essential cofactor of many enzymatic metabolic processes and as a catalyst of poorly controlled redox-cycling reactions defines its possible biological beneficial and hazardous role in the body. In this review, we discuss these two "faces" of iron in a newly conceptualized program of regulated cell death, ferroptosis. Ferroptosis is a genetically programmed iron-dependent form of regulated cell death driven by enhanced lipid peroxidation and insufficient capacity of thiol-dependent mechanisms (glutathione peroxidase 4, GPX4) to eliminate hydroperoxy-lipids. We present arguments favoring the enzymatic mechanisms of ferroptotically engaged non-heme iron of 15-lipoxygenases (15-LOX) in complexes with phosphatidylethanolamine binding protein 1 (PEBP1) as a catalyst of highly selective and specific oxidation reactions of arachidonoyl- (AA) and adrenoyl-phosphatidylethanolamines (PE). We discuss possible role of iron chaperons as control mechanisms for guided iron delivery directly to their "protein clients" thus limiting non-enzymatic redox-cycling reactions. We also consider opportunities of loosely-bound iron to contribute to the production of pro-ferroptotic lipid oxidation products. Finally, we propose a two-stage iron-dependent mechanism for iron in ferroptosis by combining its catalytic role in the 15-LOX-driven production of 15-hydroperoxy-AA-PE (HOO-AA-PE) as well as possible involvement of loosely-bound iron in oxidative cleavage of HOO-AA-PE to oxidatively truncated electrophiles capable of attacking nucleophilic targets in yet to be identified proteins leading to cell demise.

Cucumber Phospholipase D alpha gene overexpression in tobacco enhanced drought stress tolerance by regulating stomatal closure and lipid peroxidation

BACKGROUND

Plant phospholipase D (PLD), which can hydrolyze membrane phospholipids to produce phosphatidic acid (PA), a secondary signaling molecule, has been proposed to function in diverse plant stress responses. Both PLD and PA play key roles in plant growth, development, and cellular processes. PLD was suggested to mediate the regulation of stomatal movements by abscisic acid (ABA) as a response to water deficit. In this research, we characterized the roles of the cucumber phospholipase D alpha gene (CsPLDα, GenBank accession number EF363796) in the growth and tolerance of transgenic tobacco (Nicotiana tabacum) to drought stress.

RESULTS

The CsPLDα overexpression in tobacco lines correlated with the ABA synthesis and metabolism, regulated the rapid stomatal closure in drought stress, and reduced the water loss. The NtNCED1 expression levels in the transgenic lines and wild type (WT) were sharply up-regulated after 16 days of drought stress compared with those before treatment, and the expression level in the transgenic lines was significantly higher than that in the WT. The NtAOG expression level evidently improved after 8 and 16 days compared with that at 0 day of treatment and was significantly lower in the transgenic lines than in the WT. The ABA content in the transgenic lines was significantly higher than that in the WT. The CsPLDα overexpression could increase the osmolyte content and reduce the ion leakage. The proline, soluble sugar, and soluble protein contents significantly increased. By contrast, the electrolytic leakage and malondialdehyde accumulation in leaves significantly decreased. The shoot and root fresh and dry weights of the overexpression lines significantly increased. These results indicated that a significant correlation between CsPLDα overexpression and improved resistance to water deficit.

CONCLUSIONS

The plants with overexpressed CsPLDα exhibited lower water loss, higher leaf relative water content, and heavier fresh and dry matter accumulation than the WT. We proposed that CsPLDα was involved in the ABA-dependent pathway in mediating the stomatal closure and preventing the elevation of intracellular solute potential.

Tissue acylcarnitine status in a mouse model of mitochondrial β-oxidation deficiency during metabolic decompensation due to influenza virus infection

Despite judicious monitoring and care, patients with fatty acid oxidation disorders may experience metabolic decompensation due to infection which may result in rhabdomyolysis, cardiomyopathy, hypoglycemia and liver dysfunction and failure. Since clinical studies on metabolic decompensation are dangerous, we employed a preclinical model of metabolic decompensation due to infection. By infecting mice with mouse adapted influenza and using a pair-feeding strategy in a mouse model of long-chain fatty acid oxidation (Acadvl-/-), our goals were to isolate the effects of infection on tissue acylcarnitines and determine how they relate to their plasma counterparts. Applying statistical data reduction techniques (Partial Least Squares-Discriminant Analysis), we were able to identify critical acylcarnitines that were driving differentiation of our experimental groups for all the tissues studied. While plasma displayed increases in metabolites directly related to mouse VLCAD deficiency (e.g. C16 and C18), organs like the heart, muscle and liver also showed involvement of alternative pathways (e.g. medium-chain FAO and ketogenesis), suggesting adaptive measures. Matched correlation analyses showed strong correlations (r > 0.7) between plasma and tissue levels for a small number of metabolites. Overall, our results demonstrate that infection as a stress produces perturbations in metabolism in Acadvl-/- that differ greatly from WT infected and Acadvl-/- pair-fed controls. This model system will be useful for studying the effects of infection on tissue metabolism as well as evaluating interventions aimed at modulating the effects of metabolic decompensation.

Lipid Peroxidation Drives Gasdermin D-Mediated Pyroptosis in Lethal Polymicrobial Sepsis

Sepsis is a life-threatening condition caused by pathogen infection and associated with pyroptosis. Pyroptosis occurs upon activation of proinflammatory caspases and their subsequent cleavage of gasdermin D (GSDMD), resulting in GSDMD N-terminal fragments that form membrane pores to induce cell lysis. Here, we show that antioxidant defense enzyme glutathione peroxidase 4 (GPX4) and its ability to decrease lipid peroxidation, negatively regulate macrophage pyroptosis, and septic lethality in mice. Conditional Gpx4 knockout in myeloid lineage cells increases lipid peroxidation-dependent caspase-11 activation and GSDMD cleavage. The resultant N-terminal GSDMD fragments then trigger macrophage pyroptotic cell death in a phospholipase C gamma 1 (PLCG1)-dependent fashion. Administration of the antioxidant vitamin E that reduces lipid peroxidation, chemical inhibition of PLCG1, or genetic Caspase-11 deletion or Gsdmd inactivation prevents polymicrobial sepsis in Gpx4-/- mice. Collectively, this study suggests that lipid peroxidation drives GSDMD-mediated pyroptosis and hence constitutes a potential therapeutic target for lethal infection.

Brain ischemic preconditioning protects against ischemic injury and preserves the blood-brain barrier via oxidative signaling and Nrf2 activation

Brain ischemic preconditioning (IPC) with mild ischemic episodes is well known to protect the brain against subsequent ischemic challenges. However, the underlying mechanisms are poorly understood. Here we demonstrate the critical role of the master redox transcription factor, nuclear factor (erythroid-derived 2)-like 2 (Nrf2), in IPC-mediated neuroprotection and blood-brain barrier (BBB) preservation. We report that IPC causes generation of endogenous lipid electrophiles, including 4-hydroxy-2-nonenal (4-HNE), which release Nrf2 from inhibition by Keap1 (via Keap1-C288) and inhibition by glycogen synthase kinase 3β (via GSK3β-C199). Nrf2 then induces expression of its target genes, including a new target, cadherin 5, a key component of adherens junctions of the BBB. These effects culminate in mitigation of BBB leakage and of neurological deficits after stroke. Collectively, these studies are the first to demonstrate that IPC protects the BBB against ischemic injury by generation of endogenous electrophiles and activation of the Nrf2 pathway through inhibition of Keap1- and GSK3β-dependent Nrf2 degradation.

Strategies to decrease oxidative stress biomarker levels in human medical conditions: A meta-analysis on 8-iso-prostaglandin F2α

The widespread detection of elevated oxidative stress levels in many medical conditions has led to numerous efforts to design interventions to reduce its effects. Efforts have been wide-ranging, from dietary changes to administration of antioxidants, supplements, e.g., omega-3-fatty acids, and many medications. However, there is still no systemic assessment of the efficacy of treatments for oxidative stress reduction across a variety of medical conditions. The goal of this meta-analysis is, by combining multiple studies, to quantitate the change in the levels of the popular oxidative stress biomarker 8-iso-prostaglandin F2α (8-iso-PGF2α) after a variety of treatment strategies in human populations. Nearly 350 unique publications with 180 distinct strategies were included in the analysis. For each strategy, the difference between pre- or placebo and post-treatment levels calculated using Hedges' g value of effect. In general, administration of antibiotics, antihyperlipidemic agents, or changes in lifestyle (g = - 0.63, - 0.54, and 0.56) had the largest effect. Administration of supplements, antioxidants, or changes in diet (g = - 0.09, - 0.28, - 0.12) had small quantitative effects. To fully interpret the effectiveness of these treatments, comparisons to the increase in g value for each medical condition is required. For example, antioxidants in populations with coronary artery disease (CAD) reduce the 8-iso-PGF2α levels by g = - 0.34 ± 0.1, which is quantitatively considered a small effect. However, CAD populations, in comparison to healthy populations, have an increase in 8-iso-PGF2α levels by g = 0.38 ± 0.04; therefore, the overall reduction of 8-iso-PGF2α levels is ≈ 90% by this treatment in this specific medical condition. In conclusion, 8-iso-PGF2α levels can be reduced not only by antioxidants but by many other strategies. Not all strategies are equally effective at reducing 8-iso-PGF2α levels. In addition, the effectiveness of any strategy can be assessed only in relation to the medical condition investigated.

Tissue-specific molecular and cellular toxicity of Pb in the oyster (Crassostrea gigas): mRNA expression and physiological studies

Lead (Pb) is one of the ubiquitous and toxic elements in aquatic environment. In oysters, gills and digestive glands are the main target organs for Pb-induced toxicity, but there is limited information on the molecular mechanisms underlying its toxicity. The present study investigated the Pb-induced toxicity mechanisms in the Pacific oyster (Crassostrea gigas) based on transcriptome, phenotypic anchoring, and validation of targeted gene expression. Gene ontology and pathway enrichment analyses revealed the differential Pb toxicity mechanisms in the tissues. In the gills, Pb disturbed the protein metabolism, with the most significant enrichment of the "protein processing in endoplasmic reticulum" pathway. The main mechanism comprised of a Pb-stimulated calcium (Ca²⁺) increase by the up-regulation of transporter-Ca-ATPase expression. The disturbed Ca²⁺ homeostasis then further induced high expressions of endoplasmic reticulum (ER) chaperones, leading to ER stress in the oysters. Unfolded proteins induced ER associated degradation (ERAD), thereby preventing the accumulation of folding-incompetent glycoproteins. However, Pb mainly induced oxidative reduction reactions in the digestive gland with high accumulation of lipid peroxidation products and high expression of antioxidant enzymes. Further, Pb induced fatty acid β-oxidation and CYP450 catalyzed ω-oxidation due to increased metabolic expenditure for detoxification. The increased content of arachidonic acid indicated that Pb exposure might alter unsaturated fatty acid composition and disturb cellular membrane functions. Taken together, our results provided a new insight into the molecular mechanisms underlying Pb toxicity in oysters.

Oxidative stress increases M1dG, a major peroxidation-derived DNA adduct, in mitochondrial DNA

Reactive oxygen species (ROS) are formed in mitochondria during electron transport and energy generation. Elevated levels of ROS lead to increased amounts of mitochondrial DNA (mtDNA) damage. We report that levels of M1dG, a major endogenous peroxidation-derived DNA adduct, are 50-100-fold higher in mtDNA than in nuclear DNA in several different human cell lines. Treatment of cells with agents that either increase or decrease mitochondrial superoxide levels leads to increased or decreased levels of M1dG in mtDNA, respectively. Sequence analysis of adducted mtDNA suggests that M1dG residues are randomly distributed throughout the mitochondrial genome. Basal levels of M1dG in mtDNA from pulmonary microvascular endothelial cells (PMVECs) from transgenic bone morphogenetic protein receptor 2 mutant mice (BMPR2R899X) (four adducts per 106 dG) are twice as high as adduct levels in wild-type cells. A similar increase was observed in mtDNA from heterozygous null (BMPR2+/-) compared to wild-type PMVECs. Pulmonary arterial hypertension is observed in the presence of BMPR2 signaling disruptions, which are also associated with mitochondrial dysfunction and oxidant injury to endothelial tissue. Persistence of M1dG adducts in mtDNA could have implications for mutagenesis and mitochondrial gene expression, thereby contributing to the role of mitochondrial dysfunction in diseases.

Transcriptome analysis of Rana chensinensis liver under trichlorfon stress

Trichlorfon is a selective organophosphate insecticide that is widely applied in aquaculture and agriculture for control of various parasites. However, repeated and excess applications of trichlorfon often lead to water pollution and threaten non-targeted species. Our previous studies showed that trichlorfon could cause oxidative stress, lipid peroxidation and hepatic lesions in the liver of Rana chensinensis, but the related molecular mechanisms remain unclear. To explore the interference of trichlorfon in gene transcription, the differentially expressed genes in the liver of R. chensinensis exposed to trichlorfon were characterized using the RNA-seq platform. A search of all unigenes against non-redundant protein sequence (Nr), non-redundant nucleotide (Nt), Swiss-Prot, Kyoto Encyclopaedia of Genes and Genomes (KEGG), Clusters of Orthologous Groups (COG) and Gene Ontology (GO) databases resulted in 22,888, 21,719, 20,934, 16,923, 7375 and 15,631 annotations, respectively, and provided a total of 27,781 annotated unigenes. Among the annotated unigenes, 16,923 were mapped to 257 signalling pathways. A set of 3329 differentially expressed unigenes was identified by comparison of the two groups in liver. Notably, relative expression of metabolism-related genes, including both up- and down-regulated genes, were also validated by qPCR. The present study depicts the high degree of transcriptional complexity in R. chensinensis under trichlorfon stress and provides new insights into the molecular mechanisms of organophosphate insecticide toxicology. Some of these metabolism-responsive genes could be useful for understanding the toxicological mechanism of trichlorfon on non-target aquatic organisms and will contribute to the conservation of aquatic life.

Physiological impacts of acute Cu exposure on deep-sea vent mussel Bathymodiolus azoricus under a deep-sea mining activity scenario

Over the past years, several studies have been dedicated to understanding the physiological ability of the vent mussel Bathymodiolus azoricus to overcome the high metal concentrations present in their surrounding hydrothermal environment. Potential deep-sea mining activities at Azores Triple junction hydrothermal vent deposits would inevitably lead to the emergence of new fluid sources close to mussel beds, with consequent emission of high metal concentrations and potential resolubilization of Cu from minerals formed during the active phase of the vent field. Copper is an essential metal playing a key role in the activation of metalloenzymes and metalloproteins responsible for important cellular metabolic processes and tissue homeostasis. However, excessive intracellular amounts of reactive Cu ions may cause irreversible damages triggering possible cell apoptosis. In the present study, B. azoricus was exposed to increasing concentrations of Cu for 96h in conditions of temperature and hydrostatic pressure similar to those experienced at the Lucky Strike hydrothermal vent field. Specimens were kept in 1L flasks, exposed to four Cu concentrations: 0μg/L (control), 300, 800 and 1600μg/L and pressurized to 1750bar. We addressed the question of how increased Cu concentration would affect the function of antioxidant defense proteins and expression of antioxidant and immune-related genes in B. azoricus. Both antioxidant enzymatic activities and gene expression were examined in gills, mantle and digestive gland tissues of exposed vent mussels. Our study reveals that stressful short-term Cu exposure has a strong effect on molecular metabolism of the hydrothermal vent mussel, especially in gill tissue. Initially, both the stress caused by unpressurization or by Cu exposure was associated with high antioxidant enzyme activities and tissue-specific transcriptional up-regulation. However, mussels exposed to increased Cu concentrations showed both antioxidant and immune-related gene suppression. Under a mining activity scenario, the release of an excess of dissolved Cu to the vent environment may cause serious changes in cellular defense mechanisms of B. azoricus. This outcome, while adding to our knowledge of Cu toxicity, highlights the potentially deleterious impacts of mining activities on the physiology of deep-sea organisms.

Changes on lipid peroxidation,enzymatic activities and gene expression in planarian (Dugesia japonica) following exposure to perfluorooctanoic acid

We investigated perfluorooctanoic acid (PFOA)-induced stress response in planarians. We administered different concentrations of PFOA to planarians for up to 10 d. PFOA exposure resulted in significant concentration-dependent elevations in lipid peroxidation, glutathione S-transferase and caspase-3 protease activities, and a significant decline in glutathione peroxidase activities compared with control groups. Exposure to PFOA significantly up-regulated the heat shock proteins hsp70 and hsp90, and p53, and down-regulated hsp40 compared with controls. PFOA exposure also increased HSP70 protein levels, as demonstrated by western blot analysis. These alterations indicated that PFOA exposure induced a stress response and affected the regulation of oxidative stress, enzymatic activities and gene expression. These results suggest that these sensitive parameters, together with other biomarkers, could be used for evaluating toxicity, for ecological risk assessment of PFOA in freshwaters.

4-hydroxynonenal protein adducts: Key mediator in Rett syndrome oxinflammation

In the last 15 years a strong correlation between oxidative stress (OxS) and Rett syndrome (RTT), a rare neurodevelopmental disorder known to be caused in 95% of the cases, by a mutation in the methyl-CpG-binding protein 2 (MECP2) gene, has been well documented. Here, we revised, summarized and discussed the current knowledge on the role of lipid peroxidation byproducts, with special emphasis on 4-hydroxynonenal (4HNE), in RTT pathophysiology. The posttranslational modifications of proteins via 4HNE, known as 4HNE protein adducts (4NHE-PAs), causing detrimental effects on protein functions, appear to contribute to the clinical severity of the syndrome, since their levels increase significantly during the subsequent 4 clinical stages, reaching the maximum degree at stage 4, represented by a late motor deterioration. In addition, 4HNE-PA are only partially removed due to the compromised functionality of the proteasome activity, contributing therefore to the cellular damage in RTT. All this will lead to a characteristic subclinical inflammation, defined "OxInflammation", derived by a positive feedback loop between OxS byproducts and inflammatory mediators that in a long run further aggravates the clinical features of RTT patients. Therefore, in a pathology completely orphan of any therapy, aiming 4HNE as a therapeutic target could represent a coadjuvant treatment with some beneficial impact in these patients.‬‬‬.

Developmental toxicity and DNA damaging properties of silver nanoparticles in the catfish (Clarias gariepinus)

Although, silver nanoparticles (AgNPs) are used in many different products, little information is known about their toxicity in tropical fish embryos. Therefore, this study evaluated the developmental toxicity of waterborne silver nanoparticles in embryos of Clarias gariepinus. Embryos were treated with (0, 25, 50, 75ng/L silver nanoparticles) in water up to 144h postfertilization stage (PFS). Results revealed various morphological malformations including notochord curvature and edema. The mortality rate, malformations, and DNA fragmentation in embryos exposed to silver nanoparticles increased in a dose- and embryonic stage-dependent manner. The total antioxidant capacity and the activity of catalase in embryos exposed to 25ng/L silver nanoparticles were decreased significantly while the total antioxidant capacity and the activity of catalase were insignificantly increased with increasing concentrations in the embryos from 24 to 144 h-PFS exposed to 50 and 75ng/L silver nanoparticles. Lipid peroxidation values showed fluctuations with doses of silver nanoparticles. Histopathological lesions including severely distorted and wrinkled notochord were observed. The current data propose that the toxicity of silver nanoparticles in C. gariepinus embryos is caused by oxidative stress and genotoxicity.

Preheating mitigates cadmium toxicity in zebrafish livers: Evidence from promoter demethylation, gene transcription to biochemical levels

The working hypothesis for this study was that moderate heat stress would alleviate the deleterious effects of subsequent cadmium (Cd) exposure on fish. Thus, zebrafish (Danio rerio) were subjected to water maintained at 26°C and 34°C for 4days, and then exposed to 0 or 200μg/L Cd for 1 week at 26°C. Multiple indicators were measured from livers of zebrafish at different levels, including DNA, RNA, protein and enzymatic activity associated with oxidative stress, inflammation and metal transport. The ameliorative effect of preheatinging on Cd toxicity was demonstrated. In the Cd-exposed groups, preheating decreased mortality and lipid peroxidation, increased activity levels of catalase (CAT) and copper/zinc-superoxide dismutase (Cu/Zn-SOD), and up-regulated mRNA levels of heat shock protein 70 (HSP70) and heat shock factor 2 (HSF2). Preheating also mitigated Cd-induced increases in protein and mRNA levels of metallothioneins (MTs), and mRNA levels of several inflammation-related genes. Furthermore, preheating alone dramatically up-regulated mRNA levels of genes related to antioxidant and immune defenses, zinc and copper transporters, protein folding, and reduced methylation levels in the HSF binding motif of the HSP70 promoter. Overall, preheating-induced accumulation of transcripts via demethylation might support the rapid defense responses at post-transcriptional levels caused by subsequent Cd exposure, indicating an adaptive mechanism for organisms exposed to one mild stressor followed by another.

Association between iron level, glucose impairment and increased DNA damage during pregnancy

Elevated circulating ferritin has been reported to increase the risk of gestational diabetes mellitus (GDM). When high ferritin translates into high iron stores, iron excess is also a condition leading to free radical damage. We aimed to evaluate the relationship between oxidative stress (OS) induced by iron status and GDM risk in non iron-supplemented pregnant women.

METHODS

This was a pilot observational study conducted on 93 non-anemic pregnant women. Iron status was assessed at the first trimester of gestation. Blood sampling was done at 24-28 weeks' gestation for oral glucose tolerance test (OGTT), insulin and biological markers of oxidative damage tests.

RESULTS

A significant increase in DNA damage was found in patients who developed GDM. Women with elevated DNA damage had a six-fold increased risk of developing GDM (Exp (B)=6.851, P=0.038; 95% CI [1.108-42.375]). The serum ferritin levels at first trimester were significantly correlated to lipid peroxidation (rho=0.24, p=0.012). The stratified analysis suggests that ferritin is a modifying factor for the correlation of oxidative stress (OS) and glucose intolerance.

CONCLUSION

Moderate ferritin levels due to iron intake without iron-supplement, at early pregnancy is a modifying factor for the correlation of oxidative damage and glucose intolerance in pregnant women. Larger studies to evaluate the risk of food iron intake induced increased oxidative damage in offspring are warranted to propose nutrition advice regarding iron intake in women with a high risk of GDM.

Role of Donors and Recipients' Glutathione S-Transferase Gene Polymorphisms in Association of Oxidative Stress With Delayed Graft Function in Kidney Allograft Recipients

INTRODUCTION

Oxidative stress contributes to delayed graft function (DGF). Glutathione S-transferases (GSTs) are polymorphic genes which produce enzymes with protective effect against oxidative stress. This study aimed to investigate the association between donors' and recipients' GSTM1 and GSTT1 polymorphisms and DGF, creatinine clearance, and oxidative stress parameters in kidney allograft recipients.

MATERIALS AND METHODS

One hundred and eighty-two donor-recipient pairs were studied. Lipid peroxidation and total antioxidant capacity were measured in the recipients' plasma as the parameters of oxidative stress. Delayed graft function was determined based on at least 10% increase, no change, or less than 10% decrease in the serum creatinine level in 3 consecutive days during the 1st week after transplantation.

RESULTS

Lipid peroxidation was significantly greater in the recipients with DGF (P < .001). The frequency of GSTM1 null was significantly higher in the patients with DGF (odds ratio [OR], 0.38; 95% confidence interval [CI], 0.17 to 0.86; P = .02). There was also a significant association between the donors' GSTM1 polymorphism and DGF (OR, 0.31; 95% CI, 0.14 to 0.68; P = .003). A significant association was detected between combination of recipients and donors' GSTM1 polymorphism and DGF (OR, 0.20; 95% CI, 0.07 to 0.64, P = .006). The recipients' GSTM1 polymorphism, alone and in combination with donors' GSTM1 and GSTT1, significantly affected the creatinine clearance on discharge day.

CONCLUSIONS

These results suggest that the donors and recipients' GSTM1 polymorphism may be a major risk factor for oxidative stress and poor kidney allograft transplantation outcomes.

Isolevuglandins as a gauge of lipid peroxidation in human tumors

The cellular production of free radicals or reactive oxygen species (ROS) can lead to protein, lipid or DNA modifications and tumor formation. The cellular lipids undergo structural changes through the actions of enzymes (e.g. cyclooxygenases) or free radicals to form a class of compounds called Isolevuglandins (IsoLGs). The recruitment and continued exposure of tissue to ROS and IsoLGs causes increased cell proliferation, mutagenesis, loss of normal cell function and angiogenesis. The elevated concentration of ROS in cancerous tissues suggests that these mediators play an important role in cancer development. We hypothesized that tumors with elevated ROS levels would similarly possess an increased concentration of IsoLGs when compared with normal tissue. Using D11, an ScFv recombinant antibody specific for IsoLGs, we utilized immunohistochemistry to visualize the presence of IsoLG in human tumors compared to normal adjacent tissue (NAT) to the same tumor. We found that IsoLG concentrations were elevated in human breast, colon, kidney, liver, lung, pancreatic and tongue tumor cells when compared to NAT and believe that IsoLGs can be used as a gauge indicative of lipid peroxidation in tumors.

Dual signaling evoked by oxidized LDLs in vascular cells

The oxidative theory of atherosclerosis relies on the modification of low density lipoproteins (LDLs) in the vascular wall by reactive oxygen species. Modified LDLs, such as oxidized LDLs, are thought to participate in the formation of early atherosclerotic lesions (accumulation of foam cells and fatty streaks), whereas their role in advanced lesions and atherothrombotic events is more debated, because antioxidant supplementation failed to prevent coronary disease events and mortality in intervention randomized trials. As oxidized LDLs and oxidized lipids are present in atherosclerotic lesions and are able to trigger cell signaling on cultured vascular cells and macrophages, it has been proposed that they could play a role in atherogenesis and atherosclerotic vascular remodeling. Oxidized LDLs exhibit dual biological effects, which are dependent on extent of lipid peroxidation, nature of oxidized lipids (oxidized phospholipids, oxysterols, malondialdehyde, α,β-unsaturated hydroxyalkenals), concentration of oxidized LDLs and uptake by scavenger receptors (e.g. CD36, LOX-1, SRA) that signal through different transduction pathways. Moderate concentrations of mildly oxidized LDLs are proinflammatory and trigger cell migration and proliferation, whereas higher concentrations induce cell growth arrest and apoptosis. The balance between survival and apoptotic responses evoked by oxidized LDLs depends on cellular systems that regulate the cell fate, such as ceramide/sphingosine-1-phosphate rheostat, endoplasmic reticulum stress, autophagy and expression of pro/antiapoptotic proteins. In vivo, the intimal concentration of oxidized LDLs depends on the influx (hypercholesterolemia, endothelial permeability), residence time and lipid composition of LDLs, oxidative stress intensity, induction of defense mechanisms (antioxidant systems, heat shock proteins). As a consequence, the local cellular responses to oxidized LDLs may stimulate inflammatory or anti-inflammatory pathways, angiogenic or antiangiogenic responses, survival or apoptosis, thereby contributing to plaque growth, instability, complication (intraplaque hemorrhage, proteolysis, calcification, apoptosis) and rupture. Finally, these dual properties suggest that oxLDLs could be implicated at each step of atherosclerosis development, from early fatty streaks to advanced lesions, depending on the nature and concentration of their oxidized lipid content.

Lethal dysregulation of energy metabolism during embryonic vitamin E deficiency

Vitamin E (α-tocopherol, VitE) was discovered in 1922 for its role in preventing embryonic mortality. We investigated the underlying mechanisms causing lethality using targeted metabolomics analyses of zebrafish VitE-deficient embryos over five days of development, which coincided with their increased morbidity and mortality. VitE deficiency resulted in peroxidation of docosahexaenoic acid (DHA), depleting DHA-containing phospholipids, especially phosphatidylcholine, which also caused choline depletion. This increased lipid peroxidation also increased NADPH oxidation, which depleted glucose by shunting it to the pentose phosphate pathway. VitE deficiency was associated with mitochondrial dysfunction with concomitant impairment of energy homeostasis. The observed morbidity and mortality outcomes could be attenuated, but not fully reversed, by glucose injection into VitE-deficient embryos at developmental day one. Thus, embryonic VitE deficiency in vertebrates leads to a metabolic reprogramming that adversely affects methyl donor status and cellular energy homeostasis with lethal outcomes.

[The processes of lipo-peroxidation and the system of antioxidant defense in women with sleep disorders in menopause: the ethnic aspect]

The purpose of study was to evaluate the system ofperoxidation of lipids as an antioxidant defense in women of peri-menopause period with sleep disorders. The sampling included 73 examined women of peri-menopause period of Russian (n=45) and Buryat (n=28) ethnic groups. All women were applied clinical anamnestic examination. The evaluation of sleep disorders was implemented using the Stanford Center for Sleep sciences and medicine questionnaire, the insomnia subjective severity evaluation test, questionnaires of quantitative estimate of risk of occurrence of syndrome of obstructive sleep apnea and the Epworth Sleepiness Scale. According the results of survey the ethnic groups were separated on main (with sleep disorders) and control (without sleep disorders) subgroups. The processes of lipoperoxidation and the system antioxidant defense are evaluated using spectrophotometric techniques. The survey established higher rate of occurrence of troubles with falling asleep and morning awakenings in female representatives of the Russian ethnic group. The total number on the Epworth Sleepiness Scale in the Russian group amounted to 12.2±0.42 and in the Buryat group - 10.01±1.29. The study of processes of lipoperoxidation in women of the Russian ethnic group established increasing of level of ketodienes and coupled trienes (p<0.05) in subgroup with sleep disorders as compared with control group. The sleep disorders in women of Buryat ethnic group are accompanied by higher levels of substrates of lipoperoxidation with coupled doubled bounds (p<0.05), diene conjugates (p<0.05), ketodienes and coupled trienes (p<0.05). The value of coefficient of oxidative stress in female patients of Russian ethnic group amounted to 2.2 and in women of Buryat ethnic group - 3.8. The study results both demonstrate development of oxidative stress in female patients with sleep disorders in peri-menopause period in Russian and Buryat ethnic groups and substantiate ethnic specificity ofprocesses of lipoperoxidation.

Non-enzymatic oxidized metabolite of DHA, 4(RS)-4-F4t-neuroprostane protects the heart against reperfusion injury

Acute myocardial infarction leads to an increase in oxidative stress and lipid peroxidation. 4(RS)-4-F_4t-Neuroprostane (4-F_4t-NeuroP) is a mediator produced by non-enzymatic free radical peroxidation of the cardioprotective polyunsaturated fatty acid, docosahexaenoic acid (DHA). In this study, we investigated whether intra-cardiac delivery of 4-F_4t-NeuroP (0.03mg/kg) prior to occlusion (ischemia) prevents and protects rat myocardium from reperfusion damages. Using a rat model of ischemic-reperfusion (I/R), we showed that intra-cardiac infusion of 4-F_4t-NeuroP significantly decreased infarct size following reperfusion (-27%) and also reduced ventricular arrhythmia score considerably during reperfusion (-41%). Most notably, 4-F_4t-NeuroP decreased ventricular tachycardia and post-reperfusion lengthening of QT interval. The evaluation of the mitochondrial homeostasis indicates a limitation of mitochondrial swelling in response to Ca²⁺ by decreasing the mitochondrial permeability transition pore opening and increasing mitochondria membrane potential. On the other hand, mitochondrial respiration measured by oxygraphy, and mitochondrial ROS production measured with MitoSox red® were unchanged. We found decreased cytochrome c release and caspase 3 activity, indicating that 4-F_4t-NeuroP prevented reperfusion damages and reduced apoptosis. In conclusion, 4-F_4t-NeuroP derived from DHA was able to protect I/R cardiac injuries by regulating the mitochondrial homeostasis.

Ptgr1 expression is regulated by NRF2 in rat hepatocarcinogenesis and promotes cell proliferation and resistance to oxidative stress

Prostaglandin reductase-1 (Ptgr1) is an alkenal/one oxidoreductase that is involved in the catabolism of eicosanoids and lipid peroxidation such as 4-hydroxynonenal (4-HNE). Recently, we reported that Ptgr1 is overexpressed in human clinical and experimentally induced samples of hepatocellular carcinoma (HCC). However, how the expression of this gene is regulated and its role in carcinogenesis are not yet known. Here, we studied parameters associated with antioxidant responses and the mechanisms underlying the induction of Ptgr1 expression by the activation of Nuclear Factor (erythroid-derived-2)-like-2 (NRF2). For these experiments, we used two protocols of induced hepatocarcinogenesis in rats. Furthermore, we determined the effect of PTGR1 on cell proliferation and resistance to oxidative stress in cell cultures of the epithelial liver cell line, C9. Ptgr1 was overexpressed during the early phase in altered hepatocyte foci, and this high level of expression was maintained in persistent nodules until tumors developed. Ptgr1 expression was regulated by NRF2, which bound to an antioxidant response element at -653bp in the rat Ptgr1 gene. The activation of NRF2 induced the activation of an antioxidant response that included effects on proteins such as glutamate-cysteine ligase, catalytic subunit, NAD(P)H dehydrogenase quinone-1 (NQO1) and glutathione-S-transferase-P (GSTP1). These effects may have produced a reduced status that was associated with a high proliferation rate in experimental tumors. Indeed, when Ptgr1 was stably expressed, we observed a reduction in the time required for proliferation and a protective effect against hydrogen peroxide- and 4-HNE-induced cell death. These data were consistent with data showing colocalization between PTGR1 and 4-HNE protein adducts in liver nodules. These findings suggest that Ptgr1 and antioxidant responses act as a metabolic adaptation and could contribute to proliferation and cell-death evasion in liver tumor cells. Furthermore, these data indicate that Ptgr1 could be used to design early diagnostic tools or targeted therapies for HCC.

Mitochondrial control of apoptosis through modulation of cardiolipin oxidation in hepatocellular carcinoma: A novel link between oxidative stress and cancer

Altered redox status in cancer cells has been linked to lipid peroxidation induced by reactive oxygen species (ROS) and subsequent formation of reactive lipid electrophiles, especially 4-hydroxy-nonenal (4-HNE). Emerging evidence suggests that cancer cells manipulate redox status to acquire anti-apoptotic phenotype but the underlying mechanisms are poorly understood. Cardiolipin (CL), a mitochondria-specific inner membrane phospholipid, is critical for maintaining mitochondrial function. Paradoxically, liver tissues contain tetralinoleoyl cardiolipin (TLCL) as the major CL in mitochondria yet emerging evidence suggests that ROS generated in mitochondria may lead to CL peroxidation and activation of intrinsic apoptosis. It remains unclear how CL oxidation leads to apoptosis and its relevance to the pathogenesis of hepatocellular carcinoma (HCC). We employed a mass spectrometry-based lipidomic approach to profile lipids in human tissues of HCC and found that CL was gradually decreased in tumor comparing to peripheral non-cancerous tissues, accompanied by a concomitant decrease of oxidized CL and its oxidation product, 4-HNE. Incubation of liver cancer cells with TLCL significantly restored apoptotic sensitivity accompanied by an increase of CL and its oxidation products when treated with staurosporine (STS) or Sorafenib (the standard treatment for late stage HCC patients). Our studies uncovered a novel mechanism by which cancer cells adopt to evade apoptosis, highlighting the importance of mitochondrial control of apoptosis through modulation of CL oxidation and subsequent 4-HNE formation in HCC. Thus manipulation of mitochondrial CL oxidation and lipid electrophile formation may have potential therapeutic value for diseases linked to oxidative stress and mitochondrial dysfunctions.

Study on the relationship of genotoxic and oxidative potential of a new mixed chelate copper antitumoral drug, Casiopeina II-gly (Cas II-gly) in Drosophila melanogaster

The present study evaluates the superoxide dismutase (SOD) and catalase (CAT) activities in a wild strain of Drosophila melanogaster and the genotoxic potential induced by Cas II-gly (a new antineoplastic drug) using the somatic mutation and recombination test. Larvae 48h old were treated with Cas II-gly in a range of 0-1.5mM and aliquot were taken every 24h to have individuals treated for 24, 48, 72h and adulthood as well. A dose-dependent toxicity and a significant increase in SOD and CAT activities were found after a 24 and 48h treatment with 0.5-1.5mM concentrations. The comparison of the effect in enzymes with mutation indicated a positive correlation with increased genetic damage, after 24 and 48h of exposure for all concentrations tested. The addition of the genetic damage induced in each exposure time showed a significant effect, but only the small single spots had a concentration-related increase.