Hemoglobin-induced Transcriptomic Changes in Human Cerebral Arteries
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE271989 | GEO | 2024/07/15
REPOSITORIES: GEO
Similar Datasets
Project description:Hemoglobin-induced Transcriptomic Changes in Human Cerebral Arteries
| PRJNA1134252 | ENA
Project description:Extracellular hemoglobin (Hb) has been recognized as a disease trigger in hemolytic conditions such as sickle cell disease, malaria and blood transfusion. In vivo, many of the adverse effects of free Hb can be attenuated by the Hb scavenger acute phase protein haptoglobin (Hp). The primary physiologic disturbances that can be caused be free Hb are found within the cardiovascular system and Hb triggered oxidative toxicity towards the endothelium has been promoted as a potential mechanism. The molecular mechanisms of this toxicity as well as of the protective activities of Hp are not yet clear. Within this study we systematically investigated the structural, biochemical and cell biologic nature of Hb toxicity in an endothelial cell system under peroxidative stress. We identified two principal mechanisms of oxidative Hb toxicity that are mediated by globin degradation products and by modified lipoprotein species, respectively. The two damage pathways trigger diverse and discriminative inflammatory and cytotoxic responses. Hp provides structural stabilization of Hb and shields Hb’s oxidative reactions with lipoproteins providing dramatic protection against both pathways of toxicity. By these mechanisms Hp shifts Hb’s destructive pseudo-peroxidative reaction into a potential anti-oxidative function during peroxidative stress.
2015-04-30 | GSE46471 | GEO
Project description:BACKGROUND & AIMS: Recent studies revealed that hemoglobin is expressed in some non-erythrocytes and it suppresses oxidative stress when overexpressed. Oxidative stress plays a critical role in the pathogenesis of non-alcoholic steatohepatitis (NASH). This study was to investigate whether hemoglobin is expressed in hepatocytes and how it is related to oxidative stress in NASH patients. METHODS: Microarray was performed to identify differentially expressed genes in NASH. Quantitative real time PCR (qRT-PCR) was used to examine gene expression levels. Western blotting and immunofluorescence staining were employed to examine hemoglobin proteins. Flow cytometry was used to measure intracellular oxidative stress. RESULTS: Analysis of microarray gene expression data has revealed a significant increase in the expression of hemoglobin alpha (HBA1) and beta (HBB) in liver biopspies from NASH patients. Increased hemoglobin expression in NASH was validated by qRT-PCR. However, the expression of erythrocyte specific marker genes such as SPTA, SPTB, GYPA, GATA1, and ALAS2 did not change, indicating that increased hemoglobin expression in NASH was not from erythropoiesis, but could result from increased expression in hepatocytes. Immunofluorescence staining demonstrated positive HBA1 and HBB expression in the hepatocytes of NASH livers. Hemoglobin expression was also observed in human hepatocellular carcinoma HepG2 cell line. Furthermore, treatment with hydrogen peroxide, a known oxidative stress inducer, induced a dose dependent increase in HBA1 expression in HepG2 cells. Intriguingly, forced hemoglobin expression suppressed oxidative stress. CONCLUSIONS: Oxidative stress upregulates hemoglobin expression in hepatocytes. Suppression of oxidative stress by hemoglobin could be a mechanism to protect hepatocytes from oxidative damage. These findings suggest that hemoglobin is an inducible antioxidant in hepatocytes in response to increased oxidative stress as found in NASH livers. Twelve biopsy diagnosed NASH patients were included in this study. For control groups, total RNA from 5 different subjects were purchased from ADMET. These subjects are free from liver disease.
2010-10-20 | E-GEOD-24807 | biostudies-arrayexpress
Project description:Extracellular hemoglobin (Hb) has been recognized as a disease trigger in hemolytic conditions such as sickle cell disease, malaria and blood transfusion. In vivo, many of the adverse effects of free Hb can be attenuated by the Hb scavenger acute phase protein haptoglobin (Hp). The primary physiologic disturbances that can be caused be free Hb are found within the cardiovascular system and Hb triggered oxidative toxicity towards the endothelium has been promoted as a potential mechanism. The molecular mechanisms of this toxicity as well as of the protective activities of Hp are not yet clear. Within this study we systematically investigated the structural, biochemical and cell biologic nature of Hb toxicity in an endothelial cell system under peroxidative stress. We identified two principal mechanisms of oxidative Hb toxicity that are mediated by globin degradation products and by modified lipoprotein species, respectively. The two damage pathways trigger diverse and discriminative inflammatory and cytotoxic responses. Hp provides structural stabilization of Hb and shields Hb’s oxidative reactions with lipoproteins providing dramatic protection against both pathways of toxicity. By these mechanisms Hp shifts Hb’s destructive pseudo-peroxidative reaction into a potential anti-oxidative function during peroxidative stress. HPAEC: A two color common reference design was chosen with 4-8 independent biological replicates of each condition. Each experimental sample (Cy5 labeled) was hybridized against a non-treated reference sample (Cy3 labeled). HUVEC: A two color common reference design was chosen with 3-4 independent biological replicates of each condition. Each experimental sample (Cy5 labeled) was hybridized against a non-treated reference sample (Cy3 labeled).
2015-04-30 | E-GEOD-46471 | biostudies-arrayexpress
Project description:Hemoglobin (Hb) is released from red blood cells (RBC) during intravascular hemolysis. Cell free Hb has been implicated to play a pathogenic role in hemolytic diseases such as sickle cell anemia or malaria. Hydrogen peroxide (H2O2) is the most prevalent reactive oxygen species which is produced in excess during inflammation or tissue injury and has been included as a potential mediator of oxidative stress related cell and tissue damage. The biologic significance of Hbs peroxidase activity as an anti-oxidant is controversial as the radicals and higher oxidation iron species which are potentially released during these reactions could be a source of exaggerated oxidative damage. Using a cell culture model of low-flux continuous H2O2 generation by glucose-oxidase (GOx) Hb revealed the potential to protect vascular smooth muscle cells and macrophages from H2O2 mediated glutathione depletion and cell death. As revealed by gene array analysis, Hb effectively abolished H2O2 induced oxidative stress response in these cells. Through electron microscopy and quantitative mass spectrometry extensive oxidation of specific Hb amino acid residues, polymerization and precipitation was defined. This may be a consequence of potential protective mechanism within Hb. The net biologic effect of Hb, when present in oxidative rich environments, is likely a result of the balance of H2O2 consumption (protection) on one hand and the production of free radicals (damage) on the other hand. Further the extensive structural changes occurring during the reaction of ferrous Hb with H2O2 could 'absorb' a significant amount of oxidative impact and thereby further protect the environment from heme derived free radical damage. The intrinsic peroxidase activity of hemoglobin seems to be a constitutive 'enzymatic' function of Hb which adds a novel facet to the multivalent role played by the abundant oxygen carrier protein.
2009-09-15 | E-MEXP-2263 | biostudies-arrayexpress
Project description:Hypoxia, a naturally occurring phenomenon, results in tremendous losses in the growth of plants and in their productivity. On the physiological level oxygen deprivation results in distinct metabolic rearrangements, is accompanied by dehydration, and oxidative and nitrosative stresses. Six to seven core hypoxia-responsive genes, which are always induced under oxygen deprivation, have been shown to include hemoglobin 1 (Hb1) across a wide range of plant species. However, the function of this induced Hb1 is not completely understood .The importance of elevated Hb expression has been attributed mainly to its nitric oxide (NO) scavenging properties, and hence, to the elimination of this free-radical and signaling species. NO is known to accumulate under hypoxia and its level is in reciprocal relationship with the Hb expression levels. However, evidence has accumulated on Hbs as essential for normal plant development and they take part in the regulation of e.g. flowering, germination and lateral and adventitious root emergence. The physiological role of induced hemoglobin (Hb) expression and its role in NO scavenging were assessed by introducing bacterial (Vitreoscilla stercoraria) hemoglobin (VHb) to the cytoplasm and mitochondria of Arabidopsis thaliana. Heterologous expression was chosen to avoid interference with developmental functions of endogenous Hbs. Sixteen day old transformants were subjected to hypoxia or to NO donor treatment (DETA, 500 µM) for 2h and 24h and global changes in gene expression were assessed using a microarray approach. Both hypoxic and NO-treatment experiments were aimed also to reveal novel functions for Hb under abiotic stress conditions, exemplified by oxygen deprivation and NO/oxidative stresses and during normal development of Arabidopsis transformants on the background of normally expressed endogenous Hbs Hypoxia, a naturally occurring phenomenon, results in tremendous losses in the growth of plants and in their productivity. On the physiological level oxygen deprivation results in distinct metabolic rearrangements, is accompanied by dehydration, and oxidative and nitrosative stresses. Six to seven core hypoxia-responsive genes, which are always induced under oxygen deprivation, have been shown to include hemoglobin 1 (Hb1) across a wide range of plant species. However, the function of this induced Hb1 is not completely understood .The importance of elevated Hb expression has been attributed mainly to its nitric oxide (NO) scavenging properties, and hence, to the elimination of this free-radical and signaling species. NO is known to accumulate under hypoxia and its level is in reciprocal relationship with the Hb expression levels. However, evidence has accumulated on Hbs as essential for normal plant development and they take part in the regulation of e.g. flowering, germination and lateral and adventitious root emergence. The physiological role of induced hemoglobin (Hb) expression and its role in NO scavenging were assessed by introducing bacterial (Vitreoscilla stercoraria) hemoglobin (VHb) to the cytoplasm and mitochondria of Arabidopsis thaliana. Heterologous expression was chosen to avoid interference with developmental functions of endogenous Hbs. Sixteen day old transformants were subjected to hypoxia or to NO donor treatment (DETA, 500 µM) for 2h and 24h and global changes in gene expression were assessed using a microarray approach. Both hypoxic and NO-treatment experiments were aimed also to reveal novel functions for Hb under abiotic stress conditions, exemplified by oxygen deprivation and NO/oxidative stresses and during normal development of Arabidopsis transformants on the background of normally expressed endogenous Hbs
2017-10-01 | GSE72168 | GEO
Project description:Sickle cell disease (SCD) results from a point mutation in the β-globin gene forming hemoglobin S (HbS), which polymerizes in deoxygenated erythrocytes, triggering recurrent painful vaso-occlusive crises and chronic hemolytic anemia. Reactivation of fetal Hb (HbF) expression ameliorates these symptoms of SCD. Nuclear factor (erythroid derived-2)–like 2 (Nrf2) is a transcription factor that triggers cytoprotective and antioxidant pathways to limit oxidative damage and inflammation and increases HbF synthesis in CD34+ stem cell–derived erythroid progenitors. We investigated the ability of dimethyl fumarate (DMF), a small-molecule Nrf2 agonist, to activate γ-globin transcription and enhance HbF in tissue culture, murine and primate models. DMF recruited Nrf2 to the γ-globin promoters and the locus control region of the β-globin locus in erythroleukemia cells, elevated HbF in SCD donor–derived erythroid progenitors, and reduced hypoxia-induced sickling. Chronic DMF administration in SCD mice induced HbF and increased Nrf2-dependent genes to detoxify heme and limit inflammation. This improved hematological parameters, reduced plasma-free Hb, and attenuated inflammatory markers. Chronic DMF administration to nonanemic primates increased γ-globin mRNA in BM and HbF protein in red cells. DMF represents a potential therapy for SCD to induce HbF and augment vasoprotection and heme detoxification
2017-11-01 | GSE105035 | GEO
Project description:Methods of structural mass spectrometry have become more popular to study protein structure and dynamics. Among them, fast photochemical oxidation of proteins (FPOP) has several advantages such as irreversibility of modifications and more facile determination of the site of modification with single residue resolution. In the present study, FPOP analysis was applied to study the hemoglobin (Hb) – haptoglobin (Hp) complex allowing identification of respective regions altered upon the complex formation. The footprinting using a timsTOF Pro mass spectrometer allowed to obtain structural information for 84 and 76 residues in Hp and Hb, respectively, including statistically significant differences in the modification extent below 0.3 %. The most affected residues upon the complex formation were Met76 and Tyr140 in Hbα, and Tyr280 and Trp284 in Hpβ. The data allowed determination of amino acids directly involved in Hb – Hp interactions and those located outside of the interaction interface yet affected by the complex formation. Also, previously modeled interaction between Hb βTrp37 and Hp βPhe292 was not confirmed by our data.
2021-12-30 | PXD021621 | Pride
Project description:BACKGROUND & AIMS: Recent studies revealed that hemoglobin is expressed in some non-erythrocytes and it suppresses oxidative stress when overexpressed. Oxidative stress plays a critical role in the pathogenesis of non-alcoholic steatohepatitis (NASH). This study was to investigate whether hemoglobin is expressed in hepatocytes and how it is related to oxidative stress in NASH patients. METHODS: Microarray was performed to identify differentially expressed genes in NASH. Quantitative real time PCR (qRT-PCR) was used to examine gene expression levels. Western blotting and immunofluorescence staining were employed to examine hemoglobin proteins. Flow cytometry was used to measure intracellular oxidative stress. RESULTS: Analysis of microarray gene expression data has revealed a significant increase in the expression of hemoglobin alpha (HBA1) and beta (HBB) in liver biopspies from NASH patients. Increased hemoglobin expression in NASH was validated by qRT-PCR. However, the expression of erythrocyte specific marker genes such as SPTA, SPTB, GYPA, GATA1, and ALAS2 did not change, indicating that increased hemoglobin expression in NASH was not from erythropoiesis, but could result from increased expression in hepatocytes. Immunofluorescence staining demonstrated positive HBA1 and HBB expression in the hepatocytes of NASH livers. Hemoglobin expression was also observed in human hepatocellular carcinoma HepG2 cell line. Furthermore, treatment with hydrogen peroxide, a known oxidative stress inducer, induced a dose dependent increase in HBA1 expression in HepG2 cells. Intriguingly, forced hemoglobin expression suppressed oxidative stress. CONCLUSIONS: Oxidative stress upregulates hemoglobin expression in hepatocytes. Suppression of oxidative stress by hemoglobin could be a mechanism to protect hepatocytes from oxidative damage. These findings suggest that hemoglobin is an inducible antioxidant in hepatocytes in response to increased oxidative stress as found in NASH livers.
2010-10-21 | GSE24807 | GEO
Project description:Hemoglobin (Hb) released from red blood cells during hemolysis is a trigger of oxidative vascular damage with endothelial cells being a primary target. The Hb and heme scavenger proteins haptoglobin (Hp) and hemopexin (Hx) have been characterized as a sequential defense system with Hp as the primary protector and Hx as a backup when all Hp is depleted during more severe or prolonged hemolysis. The paradigm of sequential protection by the two scavengers is based on observational patient data proposed by Mueller-Eberhardt. In this study we present a mechanistic rationale for these clinical observations using a novel in vitro model of Hb triggered endothelial damage. We identified oxyHb(Fe2+) transformation to ferric Hb(Fe3+), free heme transfer from ferric Hb(Fe3+) to lipoprotein and subsequent oxidative reactions in the lipophilic phase. The accumulation of toxic lipid peroxidation products liberated during oxidation reactions lead to endothelial damage characterized by a specific gene expression pattern, reduced cellular ATP and monolayer disintegration. Quantitative analysis of key biochemical and functional parameters allowed us to precisely define the mechanisms and concentrations required for Hp and Hx to prevent this toxicity. In the case of Hp we defined an exponential relationship between Hp availability relative to oxyHb(Fe2+) and related protective activity. This exponential relationship demonstrates that large Hp quantities are required to prevent Hb toxicity. In contrast, the linear relationship between Hx concentration and protective activity allows for significant protection by the backup scavenger during conditions of large excess of free oxyHb(Fe2+) that occurs when all Hp is consumed. The diverse protective function of Hp and Hx in this model can be explained by the different target specificities of the two proteins.
2018-02-25 | GSE66283 | GEO