Hub gene identification and immune infiltration analysis in hepatocellular carcinoma: Computational approach.

In the case of hepatocellular carcinoma, there is a need to find novel immune biomarkers to predict cancer prognosis, which will help prolong patient survival. On the basis of these findings, we explored the role of the hub genes in hepatocellular carcinoma via computational analysis for future immunotherapy. To study this phenomenon, we selected three datasets downloaded from the GEO database (GSE25097, GSE76427 and GSE84402). The gene expression analysis platform (GEAP) online tool was used for the data analysis to identify the DEGs. Functional enrichment analysis was performed by GO and KEGG enrichment analysis. The genes associated with these genes were identified via Cytoscape software. Immune cell infiltration and correlation analysis were used to screen the hub genes. The results revealed that the PTTG1, NCAPG, RACGAP1, PBK, ASPM, AURKA, CDCA5, KIF20A, MELK and PRC1 genes were correlated with immune targets, and these hub gene biomarkers will aid in future cancer prognosis and immunotherapy targeting in hepatocellular carcinoma patients. Supplementary Information: The online version contains supplementary material available at 10.1007/s40203-024-00215-2.

Correction: Investigating the effect of acidic and basic precipitation on the antibacterial activity of ZnO nanoparticles against Gram-negative and Gram-positive bacteria.

Correction for 'Investigating the effect of acidic and basic precipitation on the antibacterial activity of ZnO nanoparticles against Gram-negative and Gram-positive bacteria' by Sreekanth R. et al., J. Mater. Chem. B, 2024, 12, 2180-2196, https://doi.org/10.1039/D3TB02119J.

Analysis of Somatic Mutations in the TCGA-LIHC Whole Exome Sequence to Identify the Neoantigen for Immunotherapy in Hepatocellular Carcinoma.

There are numerous clinically proven methods for treating cancer worldwide. Immunotherapy has been used to treat cancer with significant success in the current studies. The purpose of this work is to identify somatically altered target gene neoantigens and investigate liver cancer-related immune cell interaction and functional changes for potential immunotherapy in future clinical trials. Clinical patient data from the Cancer Genome Atlas (TCGA) database were used in this investigation. The R maf utility package was used to perform somatic analysis. The 17-mer peptide neoantigens were extracted using an in-house Python software called Peptide.py. Additionally, the epitope analysis was conducted using NetMHCpan4.1 program. Neopeptide immunogenicity was assessed using DeepCNN-Ineo, and tumor immune interaction, association with immune cells, correlation, and survival analysis were assessed using the TIMER web server. Based on somatic mutation analysis, we have identified the top 10 driver genes (TP53, TNN, CTNNB1, MUC16, ALB, PCLO, MUC4, ABCA13, APOB, and RYR2). From the superfamily of 20 HLA (Human leukocyte antigens) allele epitopes, we discovered 5653 neopeptides. Based on T cell receptor face hydrophobic analysis, these neopeptides were subjected to immunogenicity investigation. A mutation linked to tumor growth may have an impact on immune cells. According to this study's correlation and survival analysis, all driver genes may function as immune targets for liver cancer. These genes are recognized to be immune targets. In the future, immune checkpoint inhibitors may be developed to prolong patient survival times and prevent hepatocellular carcinoma (HCC) through immunotherapy.

COVID-19: comprehensive review on mutations and current vaccines.

Viral outbreaks had been a threat for the human race for a long time. Several epidemics and pandemics have been reported in the past with serious consequences on human health and subsequent social and economic aspects. According to WHO, viral infections continue to be a major health concern globally. Novel coronavirus, SARS-CoV-2 (Severe acute respiratory syndrome coronavirus-2) causes the most recent infectious pandemic disease, COVID-19 (Coronavirus disease-19). As of now, there were 249 million infections of COVID-19 worldwide with a high mortality of more than 5 million deaths reported; and the number of new additional cases is drastically increasing. Development of therapies to treat the infected cases and prophylactic agents including vaccines that are effective towards different variants are crucial to curtail the COVID-19 pandemic. Owing to the fact that there is a high mortality and morbidity rate along with the risk of virus causing further epidemic outbursts, development of additional effective therapeutic and preventive strategies are highly warranted. Prevention, early detection and treatment will reduce the spread of COVID-19 pandemic. The present review highlights the novel mutations and therapeutic updates associated with coronaviruses along with the clinical manifestations-diagnosis, clinical management and, prophylactic and therapeutic strategies of COVID-19 infection.

Evaluation of cell wall-associated direct extracellular electron transfer in thermophilic Geobacillus sp.

In this study, a cell wall-associated extracellular electron transfer (EET) was determined in the thermophilic Geobacillus sp. to utilize iron as a terminal electron acceptor. The direct extracellular transfer of its electrons was primarily linked to the cell wall cytochrome-c and diffusible redox mediators like flavins during the anoxic condition. Based on the azo dye decolouration and protein film voltammetry, it was revealed that, in the absence of surface polysaccharide and diffusible mediators, the cell wall-associated EET pathway was likely to be a favorable mechanism in Geobacillus sp. Since the permeability of such redox molecule is primarily limited to the cell wall, the electron transfer occurs by direct contact with cell wall-associated cytochrome and final electron acceptor. Furthermore, transfer of electrons with the help of redox shuttling molecules like riboflavin from cytochrome to cells, vice versa indicates that Geoabcillus sp. has adopted this unique pathway during an anoxic environment for its respiration. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02917-2.

Mutational analysis in international isolates and drug repurposing against SARS-CoV-2 spike protein: molecular docking and simulation approach.

The novel SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) is spreading, as the causative pathogen of coronavirus disease-19 (COVID-19). It has infected more than 1.65 billion people all over the world since it was discovered and reported 3.43 million deaths by mid of May 2021. SARS-CoV-2 enters the host cell by binding to viral surface glycoprotein (S protein) with human ACE2 (angiotensin-converting enzyme2). Spike protein (contains S1 and S2 sub-domains) molecular interaction with the host cells is considered as a major step in the viral entry and disease initiation and progression and this identifies spike protein as a promising therapeutic target against antiviral drugs. Currently, there are no efficient antiviral drugs for the prevention of COVID-19 infection. In this study, we have analyzed global 8719 spike protein sequences from patients infected with SAR-CoV-2. These SAR-CoV-2 genome sequences were downloaded from the GISAID database. By using an open reading frame (ORF) tool we have identified the spike protein sequence. With these, all spike protein amino acid sequences are subjected to multiple sequence alignment (MSA) with Wuhan strain spike protein sequence as a query sequence, and it shows all SAR-CoV strain spike proteins are 99.8% identical. In the mutational analysis, we found 639 mutations in the spike protein sequence of SARS-CoV-2 and identified/highlighted 20 common mutations L5F, T22I, T29I, H49Y, L54F, V90F, S98F, S221L, S254F, V367F, A520S, T572I, D614G, H655Y, P809S, A879S, D936Y, A1020S, A1078S, and H1101Y. Further, we have analyzed the crystal structure of the 2019-nCoV chimeric receptor-binding complex with ACE2 (PDB ID: 6VW1) as a major target protein. The spike receptor binding protein (RBD) used as target region for our studies with FDA-approved drugs for repurposing, and identified few anti-SARS-CoV2 potential drugs (Silmitasertib, AC-55541, Merimepodib, XL413, AZ3451) based on their docking score and binding mode calculations expected to strongly bind to motifs of ACE2 receptor and may show impart relief in COVID-19 patients.

A comprehensive review on the influence of light on signaling cross-talk and molecular communication against phyto-microbiome interactions.

Generally, plant growth, development, and their productivity are mainly affected by their growth rate and also depend on environmental factors such as temperature, pH, humidity, and light. The interaction between plants and pathogens are highly specific. Such specificity is well characterized by plants and pathogenic microbes in the form of a molecular signature such as pattern-recognition receptors (PRRs) and microbes-associated molecular patterns (MAMPs), which in turn trigger systemic acquired immunity in plants. A number of Arabidopsis mutant collections are available to investigate molecular and physiological changes in plants under the presence of different light conditions. Over the past decade(s), several studies have been performed by selecting Arabidopsis thaliana under the influence of red, green, blue, far/far-red, and white light. However, only few phenotypic and molecular based studies represent the modulatory effects in plants under the influence of green and blue lights. Apart from this, red light (RL) actively participates in defense mechanisms against several pathogenic infections. This evolutionary pattern of light sensitizes the pathologist to analyze a series of events in plants during various stress conditions of the natural and/or the artificial environment. This review scrutinizes the literature where red, blue, white, and green light (GL) act as sensory systems that affects physiological parameters in plants. Generally, white and RL are responsible for regulating various defense mechanisms, but, GL also participates in this process with a robust impact! In addition to this, we also focus on the activation of signaling pathways (salicylic acid and jasmonic acid) and their influence on plant immune systems against phytopathogen(s).

Nephro-protective activity of wheatgrass juice against alcohol-induced oxidative damage in rats.

The present study is an attempt to check the protective effect of fresh wheatgrass juice (WJ) as a potential therapeutic agent against alcohol-induced oxidative/nitrosative stress leading to nephrotoxicity in rats. Administration of 20% ethanol (5 g/kg b.wt/day) for 60 days resulted in a significant rise in the plasma concentrations of urea and creatinine with decreased levels of uric acid. Besides, a significant decrease in plasma electrolyte/mineral levels along with decreased activity of Na+/K+-ATPase activity was recorded in alcohol administered rats. In alcohol administered rats augmented lipid peroxidation (thio-barbituric acid reactive substance - TBARS) and nitric oxide (NOx) reflects the increased oxidative stress and nitrosative stress, moreover, we noticed a concomitant decrease in the levels of reduced glutathione (GSH) with decreased activities of antioxidant enzyme machinery viz., superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione s-transferase (GST). Administration of WJ to the alcoholic rats significantly restored the plasma biochemical markers and the kidney antioxidant status near to control group animal levels. These findings were further confirmed by the kidney histopathological studies, wherein the protective effect of WJ treatment in retaining the morphological features of the renal tissue in spite of the alcohol administration was evident. The rich repertoire of phenolic compounds present in the WJ from the freshly sprouted seeds synergistically protected the kidney from alcohol-induced damage.

Molecular Modeling, Docking, Dynamics and Simulation of Gefitinib and its Derivatives with EGFR in Non-small Cell Lung Cancer.

BACKGROUND: Gefitinib (lressa) is the most prescribed drug, highly effective to treat nonsmall cell lung cancer; primarily it was considered that targeted therapy is a kinase inhibitor. The nonsmall cell lung cancer is caused by mutation in the Epithelial Growth Factor Receptor (EGFR) gene. Iressa works by blocking the EGFR protein that helps the cancer cell growth. EGFR protein has lead to the development of anticancer therapeutics directed against EGFR inhibitor including Gefitinib for non-small cell lung cancer. METHODS: To explore the interaction between Gefitinib and its derivatives with crystal structure of EGFR to understand the better molecular insights interaction strategies. Molecular modeling of ligands (Gefitinib and its derivatives) was carried out by Avogadro software till atomic angle stable confirmation was obtained. The partial charges for the ligands were assigned as per standard protocol for molecular docking. All docking simulations were performed with AutoDockVina. Virtual screening was carried out based on binding energy and hydrogen bonding affinity. Molecular dynamics (MD) and Simulation EGFR were done using GROMACS 5.1.1 software to explore the interaction stability in a cell. RESULTS: The stable conformation for EGFR protein trajectories were captured at various time intervals 0-20ns. Few compounds screen based on high affinity as the inhibitor for EGFR may inhibit the cell cycle signaling in non-small cell lung cancer. CONCLUSION: These result suggested a computer-aided screening approach of Gefitinib derivatives with regard to their binding to EGFR for identifying novel drugs for the treatment of non-small cell lung cancer.

Association between alcohol-induced oxidative stress and membrane properties in synaptosomes: A protective role of vitamin E.

Chronic and excessive alcohol consumption leads to various neurological diseases. Synaptosomes are ideal organelles to study the functional properties of the brain in alcoholism. This study focuses on the association between oxidative stress and synaptosomal membrane properties in alcohol treated rats. Sixty day old male albino rats were treated with 20% alcohol at 5g/kg body weight/ day for sixty days. Alcohol administration significantly increased the levels of thiobarbituric acid reactive substances (TBARS) and protein carbonyls with decreased catalase, glutathione peroxidase (GPx), superoxide dismutase (SOD) activities and reduced glutathione (GSH) content in synaptosomes. Further, alcohol administration decreased (cholesterol/phospholipids) C/P ratio in synaptosomal membranes, which was further confirmed using 1,6 diphenyl 1,3 hexatriene (DPH) as fluorescent probe. Moreover, alcohol treatment also increased membrane bound Na+/K+-ATPase, Ca2+-ATPase and Mg2+-ATPase enzyme activities. Correlation (r) analysis revealed that anisotropic (γ) values were strongly associated with lipid peroxidation (r=0.678) and Na+/K+-ATPase activity (r=0.793). The results of the present study clearly indicate that lipid peroxidation was positively correlated (r=0.621) with Na+/K+-ATPase activity and C/P ratio was negatively associated (r=-0.549) in alcohol treated animals. Similar results were found on alcohol treatment (50 and 100mM) of brain synaptosomes in vitro. But with the co-treatment of vitamin E reversed these changes. In conclusion, synaptosomal membranes properties are impaired due to increased oxidative stress, changes in lipid composition, altered fluidity and membrane bound enzyme activities. And treatment with vitamin E renders protection against ethanol-induced membrane alterations.

In vivo and molecular docking studies using whole extract and phytocompounds of Aegle marmelos fruit protective effects against Isoproterenol-induced Myocardial infarction in rats.

Myocardial infarction (MI) is a leading major health problem with increased morbidity and mortality worldwide. The present study investigates isoproterenol (ISO) induced MI and the beneficial role of Aegle marmelos fruit extract (AMFE) in rats. Our results indicated the significant augmentation of plasma nitric oxide (NOx) levels, C-reactive protein (CRP), homocysteine, apolipoprotein B (apo-B), cardiac tissue lipid peroxidation and liver 3-hydroxy-3 methyl glutaryl CoA (HMG-CoA) reductase activity in ISO treated rats (85mg/kg b.wt) with a concomitant decrease in plasma apolipoprotein A1 (apo-A), lipase activity, paraoxonase-1 activity and cardiac tissue taurine levels when compared with controls. However, pretreatment of ISO administered rats with AMFE (150mg/kg b.wt/day for 45 days) markedly brought the observed alterations toward near normal level indicating its protective role against MI. Further, we have extended our studies to study the interaction of important phytocompounds, marmesin, marmin, umbelliferone and impertonin, present in AMFE with key enzymes, HMG-CoA reductase, iNOS, lipoprotein lipase and paraoxonase using AutoDock4. Molecular docking analysis indicated that HMG-CoA reductase, inducible nitric oxide synthase (iNOS) and lipoprotein lipase formed a strong enzyme ligand complex with impertonin. While the marmesin showed strong interaction with paraoxonase enzyme. In conclusion, our results suggest that AMFE acts as a strong protective agent against ISO-induced MI, and the bioactive compounds are responsible for this protective action which is confirmed by molecular docking studies.

Association between alcohol-induced erythrocyte membrane alterations and hemolysis in chronic alcoholics.

The present study aimed to understand the association between erythrocyte membrane alterations and hemolysis in chronic alcoholics. Study was conducted on human male volunteers aged between 35-45 years with a drinking history of 8-10 years. Results showed that plasma marker enzymes AST, ALT, ALP and γGT were increased in alcoholic subjects. Plasma and erythrocyte membrane lipid peroxidation, erythrocyte lysate nitric oxide (NOx) levels were also increased significantly in alcoholics. Furthermore, erythrocyte membrane protein carbonyls, total cholesterol, phospholipid and cholesterol/phospholipid (C/P) ratio were increased in alcoholics. SDS-PAGE analysis of erythrocyte membrane proteins revealed that increased density of band 3, protein 4.2, 4.9, actin and glycophorins, whereas glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and glycophorin A showed slight increase, however, decreased ankyrin with no change in spectrins (α and ß) and protein 4.1 densities were observed in alcoholics. Moreover, alcoholics red blood cells showed altered morphology with decreased resistance to osmotic hemolysis. Increased hemolysis showed strong positive association with lipid peroxidation (r = 0.703, p<0.05), protein carbonyls (r = 0.754, p<0.05), lysate NOx (r = 0.654, p<0.05) and weak association with C/P ratio (r = 0.240, p<0.05). Bottom line, increased lipid and protein oxidation, altered membrane C/P ratio and membrane cytoskeletal protein profile might be responsible for the increased hemolysis in alcoholics.

Nephro-protective action of P. santalinus against alcohol-induced biochemical alterations and oxidative damage in rats.

The present study investigated the antioxidant potential of P. santalinus heartwood methanolic extract (PSE) against alcohol-induced nephro-toxicity. The results indicated an increase in the concentration of kidney damage plasma markers, urea and creatinine with a concomitant decrease in the concentration of uric acid in alcohol-administered rats. A significant decrease in plasma electrolytes and mineral levels with increased kidney thiobarbituric acid reactive substances (TBARS) and nitric oxide (NOx) levels was also observed. PSE treatment to alcohol-administered rats effectively prevented the elevation in TBARS and NOx levels. Decreased activity of Na+/K+-ATPase in alcohol administered rats was brought to near normal levels with treatment of PSE. Chronic alcohol consumption affects antioxidant enzymatic activity and reabsorption function of the kidney which is evident from the decreased level of GSH as well as the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione s-transferase (GST). However, treatment with PSE to alcohol-administered rats significantly enhanced these enzymatic activities and reduced glutathione (GSH) content close to normal level. Alcohol-induced organ damage was evident from morphological changes in the kidney. Nevertheless, administration of PSE effectively restored these morphological changes to normal. The flavonoid and tannoid compounds might have protective activity against alcohol-induced oxidative/nitrosative stress mediated kidney damage.

Modulatory role of Pterocarpus santalinus against alcohol-induced liver oxidative/nitrosative damage in rats.

Pterocarpus santalinus, a traditional medicinal plant has shown protective mechanisms against various complications. The aim of the present study is to evaluate therapeutic efficacy of P. santalinus heartwood methanolic extract (PSE) against alcohol-induced oxidative/nitrosative stress leading to hepatotoxicity. In-vitro studies revealed that PSE possess strong DPPH (1,1-diphenyl-2-picryl hydrazyl) and nitric oxide radical scavenging activity. For in vivo studies male albino Wistar rats were treated with 20% alcohol (5g/kg b.wt/day) and PSE (250mg/kg b.wt/day) for 60days. Results showed that alcohol administration significantly altered plasma lipid profile with marked increase in the levels of plasma transaminases (ALT and AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and gamma glutamyl transferase (γGT). Moreover, lipid peroxides, nitric oxide (NOx) levels in plasma and liver were increased with increased iNOS protein expression in liver was noticed in alcohol administered rats and these levels were significantly brought back close to normal level by PSE administration except iNOS protein expression. Alcohol administration also decreased the content of reduced glutathione (GSH) and activities of glutathione peroxidase (GPx), glutathione-s transferase (GST), glutathione reductase (GR), superoxide dismutase (SOD) and catalase (CAT) in liver, which were significantly enhanced by administration of PSE. The active compounds pterostilbene, lignan and lupeols present in PSE might have shown protection against alcohol-induced hepatic damage by possibly reducing the rate of lipid peroxidation, NOx levels and increasing the antioxidant defence mechanism in alcohol administered rats. Both biochemical and histopathological results in the alcohol-induced liver damage model emphasize beneficial action of PSE as a hepatoprotective agent.

Influence of Altered Hormonal Status on Platelet 5-HT and MAO-B Activity in Cigarette Smokers.

The present study was designed to understand the cigarette smoking-induced alterations in hormones and the resulting changes in platelet serotonin (5-hydroxytryptamine, 5-HT) and monoamine oxidase (MAO-B) activity in chronic smokers. Human male volunteers aged 35 ± 8 years, were divided into two groups, namely controls and smokers (12 ± 2 cigarettes per day for 7-10 years). Results showed that cigarette smoking significantly (p < 0.05) elevated plasma triiodothyronine (T3), cortisol and testosterone levels with significant (p < 0.05) reduction in plasma tryptophan and thyroxin (T4). Moreover, smokers showed reduced platelet 5-HT levels and MAO-B activity. In smokers, plasma cortisol was negatively correlated with tryptophan (r = -0.386), platelet MAO-B (r = -0.264), and 5-HT (r = -0.671), and positively correlated with testosterone (r = 0.428). However, testosterone was negatively correlated with platelet MAO-B (r = -0.315), and 5-HT (r = -.419) in smokers. Further, smokers plasma T3 levels were negatively correlated with platelet MAO-B (r = -0.398), and 5-HT (r = -0.541), whereas T4 levels were positively correlated with platelet MAO-B (r = 0.369), and 5-HT (r = 0.454). In conclusion, our study showed that altered testosterone and cortisol levels may aggravate behavior, mood disturbances and symptoms of depression by decreasing platelet 5-HT and MAO-B activity in smokers.

Regulation of hypoxia-inducible factor-α isoforms and redox state by carotid body neural activity in rats.

Previous studies reported that chronic intermittent hypoxia (CIH) results in an imbalanced expression of hypoxia-inducible factor-α (HIF-α) isoforms and oxidative stress in rodents, which may be due either to the direct effect of CIH or indirectly via hitherto uncharacterized mechanism(s). As neural activity is a potent regulator of gene transcription, we hypothesized that carotid body (CB) neural activity contributes to CIH-induced HIF-α isoform expression and oxidative stress in the chemoreflex pathway. Experiments were performed on adult rats exposed to CIH for 10 days. Rats exposed to CIH exhibited: increased HIF-1α and decreased HIF-2α expression; increased NADPH oxidase 2 and decreased superoxide dismutase 2 expression; and oxidative stress in the nucleus tractus solitarius and rostral ventrolateral medulla as well as in the adrenal medulla (AM), a major end organ of the sympathetic nervous system. Selective ablation of the CB abolished these effects. In the AM, sympathetic activation by the CB chemoreflex mediates CIH-induced HIF-α isoform imbalance via muscarinic acetylcholine receptor-mediated Ca(2+) influx, and the resultant activation of mammalian target of rapamycin pathway and calpain proteases. Rats exposed to CIH presented with hypertension, elevated sympathetic activity and increased circulating catecholamines. Selective ablation of either the CB (afferent pathway) or sympathetic innervation to the AM (efferent pathway) abolished these effects. These observations uncover CB neural activity-dependent regulation of HIF-α isoforms and the redox state by CIH in the central and peripheral nervous systems associated with the chemoreflex.

Alcohol-induced oxidative stress in rat liver microsomes: Protective effect of Emblica officinalis.

The protective effect of Emblica officinalis fruit extract (EFE) against alcohol-induced oxidative damage in liver microsomes was investigated in rats. EFE (250mg/kg b.wt/day) and alcohol (5g/kg b.wt/day, 20%, w/v) were administered orally to animals for 60 days. Alcohol administration significantly increased lipid peroxidation, protein carbonyls with decreased sulfhydryl groups in microsomes, which were significantly restored to normal levels in EFE and alcohol co-administered rats. Alcohol administration also markedly decreased the levels of reduced glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) in the liver microsomes, which were prevented with EFE administration. Further, alcohol administration significantly increased the activities of cytochrome P-450, Na(+)/K(+) and Mg(2+) ATPases and also membrane fluidity. But, administration of EFE along with alcohol restored the all above enzyme activities and membrane fluidity to normal level. Thus, EFE showed protective effects against alcohol-induced oxidative damage by possibly reducing the rate of lipid peroxidation and restoring the various membrane bound and antioxidant enzyme activities to normal levels, and also by protecting the membrane integrity in rat liver microsomes. In conclusion, the polyphenolic compounds including flavonoid and tannoid compounds present in EFE might be playing a major role against alcohol-induced oxidative stress in rats.

Mutual antagonism between hypoxia-inducible factors 1α and 2α regulates oxygen sensing and cardio-respiratory homeostasis.

Breathing and blood pressure are under constant homeostatic regulation to maintain optimal oxygen delivery to the tissues. Chemosensory reflexes initiated by the carotid body and catecholamine secretion from the adrenal medulla are the principal mechanisms for maintaining respiratory and cardiovascular homeostasis; however, the underlying molecular mechanisms are not known. Here, we report that balanced activity of hypoxia-inducible factor-1 (HIF-1) and HIF-2 is critical for oxygen sensing by the carotid body and adrenal medulla, and for their control of cardio-respiratory function. In Hif2α(+/-) mice, partial HIF-2α deficiency increased levels of HIF-1α and NADPH oxidase 2, leading to an oxidized intracellular redox state, exaggerated hypoxic sensitivity, and cardio-respiratory abnormalities, which were reversed by treatment with a HIF-1α inhibitor or a superoxide anion scavenger. Conversely, in Hif1α(+/-) mice, partial HIF-1α deficiency increased levels of HIF-2α and superoxide dismutase 2, leading to a reduced intracellular redox state, blunted oxygen sensing, and impaired carotid body and ventilatory responses to chronic hypoxia, which were corrected by treatment with a HIF-2α inhibitor. None of the abnormalities observed in Hif1α(+/-) mice or Hif2α(+/-) mice were observed in Hif1α(+/-);Hif2α(+/-) mice. These observations demonstrate that redox balance, which is determined by mutual antagonism between HIF-α isoforms, establishes the set point for hypoxic sensing by the carotid body and adrenal medulla, and is required for maintenance of cardio-respiratory homeostasis.

Gender differences in alcohol-induced oxidative stress and altered membrane properties in erythrocytes of rats.

Alcohol-induced oxidative stress leads to imbalance between reactive oxygen species (ROS) and the antioxidant defense system, resulting in oxidative damage to membrane components such as lipids and proteins, ultimately altering membrane properties. In this study, we assessed oxidative stress status and alterations in erythrocyte membrane properties in alcohol-administered rats with respect to gender difference. Alcohol (20% v/v) administered rats of both genders showed significant changes in plasma lipid profile with elevated nitrite/nitrate levels. Furthermore, alcohol-administration significantly decreased erythrocyte antioxidant enzymes and enhanced erythrocyte membrane lipid peroxidation, cholesterol/phospholipid (C/P) ratio and Na+/K(+)-ATPase activity in both males and females. Besides, anisotropic studies revealed that alcohol-administration significantly decreased erythrocyte membrane fluidity. In conclusion, alcohol-administration significantly increased oxidative stress by decreasing antioxidant status, and subsequent generation of ROS altered membrane properties by altering fluidity and Na+/K(+)-ATPase activity. Female rats were more vulnerable to alcohol-induced biochemical and biophysical changes in plasma and erythrocyte including oxidative stress than male rats.

Alcohol-induced oxidative/nitrosative stress alters brain mitochondrial membrane properties.

Chronic alcohol consumption causes numerous biochemical and biophysical changes in the central nervous system, in which mitochondria is the primary organelle affected. In the present study, we hypothesized that alcohol alters the mitochondrial membrane properties and leads to mitochondrial dysfunction via mitochondrial reactive oxygen species (mROS) and reactive nitrogen species (RNS). Alcohol-induced hypoxia further enhances these effects. Administration of alcohol to rats significantly increased the mitochondrial lipid peroxidation and protein oxidation with decreased SOD2 mRNA and protein expression was decreased, while nitric oxide (NO) levels and expression of iNOS and nNOS in brain cortex were increased. In addition, alcohol augmented HIF-1α mRNA and protein expression in the brain cortex. Results from this study showed that alcohol administration to rats decreased mitochondrial complex I, III, IV activities, Na(+)/K(+)-ATPase activity and cardiolipin content with increased anisotropic value. Cardiolipin regulates numerous enzyme activities, especially those related to oxidative phosphorylation and coupled respiration. In the present study, decreased cardiolipin could be ascribed to ROS/RNS-induced damage. In conclusion, alcohol-induced ROS/RNS is responsible for the altered mitochondrial membrane properties, and alcohol-induced hypoxia further enhance these alterations, which ultimately leads to mitochondrial dysfunction.