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Li H, Xu Y, Li W, Zhang L, Zhang X, Li B, Chen Y, Wang X, Zhu C. Novel insights into the immune cell landscape and gene signatures in autism spectrum disorder by bioinformatics and clinical analysis. Front Immunol 2023; 13:1082950. [PMID: 36761165 PMCID: PMC9905846 DOI: 10.3389/fimmu.2022.1082950] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 12/28/2022] [Indexed: 01/26/2023] Open
Abstract
The pathogenesis of autism spectrum disorder (ASD) is not well understood, especially in terms of immunity and inflammation, and there are currently no early diagnostic or treatment methods. In this study, we obtained six existing Gene Expression Omnibus transcriptome datasets from the blood of ASD patients. We performed functional enrichment analysis, PPI analysis, CIBERSORT algorithm, and Spearman correlation analysis, with a focus on expression profiling in hub genes and immune cells. We validated that monocytes and nonclassical monocytes were upregulated in the ASD group using peripheral blood (30 children with ASD and 30 age and sex-matched typically developing children) using flow cytometry. The receiver operating characteristic curves (PSMC4 and ALAS2) and analysis stratified by ASD severity (LIlRB1 and CD69) showed that they had predictive value using the "training" and verification groups. Three immune cell types - monocytes, M2 macrophages, and activated dendritic cells - had different degrees of correlation with 15 identified hub genes. In addition, we analyzed the miRNA-mRNA network and agents-gene interactions using miRNA databases (starBase and miRDB) and the DSigDB database. Two miRNAs (miR-342-3p and miR-1321) and 23 agents were linked with ASD. These findings suggest that dysregulation of the immune system may contribute to ASD development, especially dysregulation of monocytes and monocyte-derived cells. ASD-related hub genes may serve as potential predictors for ASD, and the potential ASD-related miRNAs and agents identified here may open up new strategies for the prevention and treatment of ASD.
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Affiliation(s)
- Hongwei Li
- Henan Key Laboratory of Child Brain Injury and Henan Pediatric Clinical Research Center, Institute of Neuroscience and the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yiran Xu
- Henan Key Laboratory of Child Brain Injury and Henan Pediatric Clinical Research Center, Institute of Neuroscience and the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China,National Health Council (NHC) Key Laboratory of Birth Defects Prevention, Henan Key Laboratory of Population Defects Prevention, Zhengzhou, China
| | - Wenhua Li
- Henan Key Laboratory of Child Brain Injury and Henan Pediatric Clinical Research Center, Institute of Neuroscience and the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Lingling Zhang
- Henan Key Laboratory of Child Brain Injury and Henan Pediatric Clinical Research Center, Institute of Neuroscience and the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xiaoli Zhang
- Henan Key Laboratory of Child Brain Injury and Henan Pediatric Clinical Research Center, Institute of Neuroscience and the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Bingbing Li
- Henan Key Laboratory of Child Brain Injury and Henan Pediatric Clinical Research Center, Institute of Neuroscience and the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yiwen Chen
- Henan Key Laboratory of Child Brain Injury and Henan Pediatric Clinical Research Center, Institute of Neuroscience and the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xiaoyang Wang
- Henan Key Laboratory of Child Brain Injury and Henan Pediatric Clinical Research Center, Institute of Neuroscience and the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Centre of Perinatal Medicine and Health, Institute of Clinical Science, University of Gothenburg, Gothenburg, Sweden
| | - Changlian Zhu
- Henan Key Laboratory of Child Brain Injury and Henan Pediatric Clinical Research Center, Institute of Neuroscience and the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden,*Correspondence: Changlian Zhu, ;;
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Keller TCS, Lechauve C, Keller AS, Brooks S, Weiss MJ, Columbus L, Ackerman H, Cortese-Krott MM, Isakson BE. The role of globins in cardiovascular physiology. Physiol Rev 2022; 102:859-892. [PMID: 34486392 PMCID: PMC8799389 DOI: 10.1152/physrev.00037.2020] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 08/25/2021] [Accepted: 08/27/2021] [Indexed: 12/11/2022] Open
Abstract
Globin proteins exist in every cell type of the vasculature, from erythrocytes to endothelial cells, vascular smooth muscle cells, and peripheral nerve cells. Many globin subtypes are also expressed in muscle tissues (including cardiac and skeletal muscle), in other organ-specific cell types, and in cells of the central nervous system (CNS). The ability of each of these globins to interact with molecular oxygen (O2) and nitric oxide (NO) is preserved across these contexts. Endothelial α-globin is an example of extraerythrocytic globin expression. Other globins, including myoglobin, cytoglobin, and neuroglobin, are observed in other vascular tissues. Myoglobin is observed primarily in skeletal muscle and smooth muscle cells surrounding the aorta or other large arteries. Cytoglobin is found in vascular smooth muscle but can also be expressed in nonvascular cell types, especially in oxidative stress conditions after ischemic insult. Neuroglobin was first observed in neuronal cells, and its expression appears to be restricted mainly to the CNS and the peripheral nervous system. Brain and CNS neurons expressing neuroglobin are positioned close to many arteries within the brain parenchyma and can control smooth muscle contraction and thus tissue perfusion and vascular reactivity. Overall, reactions between NO and globin heme iron contribute to vascular homeostasis by regulating vasodilatory NO signals and scavenging reactive species in cells of the mammalian vascular system. Here, we discuss how globin proteins affect vascular physiology, with a focus on NO biology, and offer perspectives for future study of these functions.
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Affiliation(s)
- T C Stevenson Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Christophe Lechauve
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Alexander S Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Steven Brooks
- Physiology Unit, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Rockville, Maryland
| | - Mitchell J Weiss
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Linda Columbus
- Department of Chemistry, University of Virginia, Charlottesville, Virginia
| | - Hans Ackerman
- Physiology Unit, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Rockville, Maryland
| | - Miriam M Cortese-Krott
- Myocardial Infarction Research Laboratory, Department of Cardiology, Pulmonology, and Angiology, Medical Faculty, Heinrich Heine University of Düsseldorf, Düsseldorf, Germany
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia
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3
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Han G, Cao C, Yang X, Zhao GW, Hu XJ, Yu DL, Yang RF, Yang K, Zhang YY, Wang WT, Liu XZ, Xu P, Liu XH, Chen P, Xue Z, Liu DP, Lv X. Nrf2 expands the intracellular pool of the chaperone AHSP in a cellular model of β-thalassemia. Redox Biol 2022; 50:102239. [PMID: 35092867 PMCID: PMC8801382 DOI: 10.1016/j.redox.2022.102239] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/21/2021] [Accepted: 01/14/2022] [Indexed: 12/30/2022] Open
Abstract
In β-thalassemia, free α-globin chains are unstable and tend to aggregate or degrade, releasing toxic heme, porphyrins and iron, which produce reactive oxygen species (ROS). α-Hemoglobin-stabilizing protein (AHSP) is a potential modifier of β-thalassemia due to its ability to escort free α-globin and inhibit the cellular production of ROS. The influence of AHSP on the redox equilibrium raises the question of whether AHSP expression is regulated by components of ROS signaling pathways and/or canonical redox proteins. Here, we report that AHSP expression in K562 cells could be stimulated by NFE2-related factor 2 (Nrf2) and its agonist tert-butylhydroquinone (tBHQ). This tBHQ-induced increase in AHSP expression was also observed in Ter119+ mouse erythroblasts at each individual stage during terminal erythroid differentiation. We further report that the AHSP level was elevated in α-globin-overexpressing K562 cells and staged erythroblasts from βIVS-2-654 thalassemic mice. tBHQ treatment partially alleviated, whereas Nrf2 or AHSP knockdown exacerbated, α-globin precipitation and ROS production in fetal liver-derived thalassemic erythroid cells. MafG and Nrf2 occupancy at the MARE-1 site downstream of the AHSP transcription start site was detected in K562 cells. Finally, we show that MafG facilitated the activation of the AHSP gene in K562 cells by Nrf2. Our results demonstrate Nrf2-mediated feedback regulation of AHSP in response to excess α-globin, as occurs in β-thalassemia.
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4
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Che Yaacob NS, Islam MA, Alsaleh H, Ibrahim IK, Hassan R. Alpha-hemoglobin-stabilizing protein (AHSP): a modulatory factor in β-thalassemia. Int J Hematol 2020; 111:352-359. [PMID: 31894534 DOI: 10.1007/s12185-019-02806-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/11/2019] [Accepted: 12/12/2019] [Indexed: 11/30/2022]
Abstract
Hemoglobin (Hb) is an iron-containing metalloprotein that transports oxygen molecules from the lungs to the rest of the human body. Among the different variants of Hb, HbA1 is the most common and is composed of two alpha (αHb) and two beta globin chains (βHb) constructing a heterotetrameric protein complex (α2β2). Due to the higher number of AHSP genes, there is a tendency to produce approximately twice as much of α subunit as β subunit. Therefore, there is a chance of presenting excess α subunit leftover in human blood plasma; excess subunits subsequently bind with each other and aggregates β-thalassemia occurs due to lack of or reduced numbers of βHb subunit. Alpha-hemoglobin-stabilizing protein (AHSP) is a scavenger protein which acts as a molecular chaperon by reversibly binding with free αHb forming a complex (AHSP-αHb) that prevents aggregation and precipitation preventing deleterious effects towards developing serious human diseases including β-thalassemia. Clinical severity worsens if mutations in AHSP gene co-occur in patients with β-thalassemia. Considering the mechanism of action of AHSP and its contribution to ameliorating β-thalassemia severity, it could potentially be used as a modulatory agent in the treatment of β-thalassemia.
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Affiliation(s)
- Nur Suraya Che Yaacob
- Department of Haematology, School of Medical Sciences, Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Md Asiful Islam
- Department of Haematology, School of Medical Sciences, Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Heba Alsaleh
- Department of Haematology, School of Medical Sciences, Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Ibrahim Khidir Ibrahim
- Department of Haematology, School of Medical Sciences, Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia.,Department of Haematology, Faculty of Medical Laboratory Sciences, Al-Neelain University, Khartoum, Sudan
| | - Rosline Hassan
- Department of Haematology, School of Medical Sciences, Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia.
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5
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Lechauve C, Butcher JT, Freiwan A, Biwer LA, Keith JM, Good ME, Ackerman H, Tillman HS, Kiger L, Isakson BE, Weiss MJ. Endothelial cell α-globin and its molecular chaperone α-hemoglobin-stabilizing protein regulate arteriolar contractility. J Clin Invest 2018; 128:5073-5082. [PMID: 30295646 DOI: 10.1172/jci99933] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 08/21/2018] [Indexed: 12/18/2022] Open
Abstract
Arteriolar endothelial cell-expressed (EC-expressed) α-globin binds endothelial NOS (eNOS) and degrades its enzymatic product, NO, via dioxygenation, thereby lessening the vasodilatory effects of NO on nearby vascular smooth muscle. Although this reaction potentially affects vascular physiology, the mechanisms that regulate α-globin expression and dioxygenase activity in ECs are unknown. Without β-globin, α-globin is unstable and cytotoxic, particularly in its oxidized form, which is generated by dioxygenation and recycled via endogenous reductases. We show that the molecular chaperone α-hemoglobin-stabilizing protein (AHSP) promotes arteriolar α-globin expression in vivo and facilitates its reduction by eNOS. In Ahsp-/- mice, EC α-globin was decreased by 70%. Ahsp-/- and Hba1-/- mice exhibited similar evidence of increased vascular NO signaling, including arteriolar dilation, blunted α1-adrenergic vasoconstriction, and reduced blood pressure. Purified α-globin bound eNOS or AHSP, but not both together. In ECs in culture, eNOS or AHSP enhanced α-globin expression posttranscriptionally. However, only AHSP prevented oxidized α-globin precipitation in solution. Finally, eNOS reduced AHSP-bound α-globin approximately 6-fold faster than did the major erythrocyte hemoglobin reductases (cytochrome B5 reductase plus cytochrome B5). Our data support a model whereby redox-sensitive shuttling of EC α-globin between AHSP and eNOS regulates EC NO degradation and vascular tone.
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Affiliation(s)
- Christophe Lechauve
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Joshua T Butcher
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Abdullah Freiwan
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Lauren A Biwer
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Julia M Keith
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Miranda E Good
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Hans Ackerman
- Laboratory of Malaria and Vector Research, National Institutes of Allergy and Infectious Diseases, Rockville, Maryland, USA
| | - Heather S Tillman
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | | | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Mitchell J Weiss
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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6
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Sjodt M, Macdonald R, Marshall JD, Clayton J, Olson JS, Phillips M, Gell DA, Wereszczynski J, Clubb RT. Energetics underlying hemin extraction from human hemoglobin by Staphylococcus aureus. J Biol Chem 2018. [PMID: 29540481 DOI: 10.1074/jbc.ra117.000803] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Staphylococcus aureus is a leading cause of life-threatening infections in the United States. It actively acquires the essential nutrient iron from human hemoglobin (Hb) using the iron-regulated surface-determinant (Isd) system. This process is initiated when the closely related bacterial IsdB and IsdH receptors bind to Hb and extract its hemin through a conserved tri-domain unit that contains two NEAr iron Transporter (NEAT) domains that are connected by a helical linker domain. Previously, we demonstrated that the tri-domain unit within IsdH (IsdHN2N3) triggers hemin release by distorting Hb's F-helix. Here, we report that IsdHN2N3 promotes hemin release from both the α- and β-subunits. Using a receptor mutant that only binds to the α-subunit of Hb and a stopped-flow transfer assay, we determined the energetics and micro-rate constants of hemin extraction from tetrameric Hb. We found that at 37 °C, the receptor accelerates hemin release from Hb up to 13,400-fold, with an activation enthalpy of 19.5 ± 1.1 kcal/mol. We propose that hemin removal requires the rate-limiting hydrolytic cleavage of the axial HisF8 Nϵ-Fe3+ bond, which, based on molecular dynamics simulations, may be facilitated by receptor-induced bond hydration. Isothermal titration calorimetry experiments revealed that two distinct IsdHN2N3·Hb protein·protein interfaces promote hemin release. A high-affinity receptor·Hb(A-helix) interface contributed ∼95% of the total binding standard free energy, enabling much weaker receptor interactions with Hb's F-helix that distort its hemin pocket and cause unfavorable changes in the binding enthalpy. We present a model indicating that receptor-introduced structural distortions and increased solvation underlie the IsdH-mediated hemin extraction mechanism.
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Affiliation(s)
- Megan Sjodt
- From the Department of Chemistry and Biochemistry.,UCLA-DOE Institute of Genomics and Proteomics, and
| | - Ramsay Macdonald
- From the Department of Chemistry and Biochemistry.,UCLA-DOE Institute of Genomics and Proteomics, and
| | | | - Joseph Clayton
- the Department of Physics and Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, Chicago, Illinois 60616
| | - John S Olson
- the Department of BioSciences, Rice University, Houston, Texas 77251, and
| | | | - David A Gell
- the School of Medicine, University of Tasmania, Hobart, Tasmania 7000, Australia
| | - Jeff Wereszczynski
- the Department of Physics and Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, Chicago, Illinois 60616
| | - Robert T Clubb
- From the Department of Chemistry and Biochemistry, .,UCLA-DOE Institute of Genomics and Proteomics, and.,Molecular Biology Institute, UCLA, Los Angeles, California 90095
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7
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Gell DA. Structure and function of haemoglobins. Blood Cells Mol Dis 2017; 70:13-42. [PMID: 29126700 DOI: 10.1016/j.bcmd.2017.10.006] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 10/29/2017] [Accepted: 10/30/2017] [Indexed: 12/18/2022]
Abstract
Haemoglobin (Hb) is widely known as the iron-containing protein in blood that is essential for O2 transport in mammals. Less widely recognised is that erythrocyte Hb belongs to a large family of Hb proteins with members distributed across all three domains of life-bacteria, archaea and eukaryotes. This review, aimed chiefly at researchers new to the field, attempts a broad overview of the diversity, and common features, in Hb structure and function. Topics include structural and functional classification of Hbs; principles of O2 binding affinity and selectivity between O2/NO/CO and other small ligands; hexacoordinate (containing bis-imidazole coordinated haem) Hbs; bacterial truncated Hbs; flavohaemoglobins; enzymatic reactions of Hbs with bioactive gases, particularly NO, and protection from nitrosative stress; and, sensor Hbs. A final section sketches the evolution of work on the structural basis for allosteric O2 binding by mammalian RBC Hb, including the development of newer kinetic models. Where possible, reference to historical works is included, in order to provide context for current advances in Hb research.
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Affiliation(s)
- David A Gell
- School of Medicine, University of Tasmania, TAS 7000, Australia.
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Best SP, Levina A, Glover C, Johannessen B, Kappen P, Lay PA. XAS spectroelectrochemistry: reliable measurement of X-ray absorption spectra from redox manipulated solutions at room temperature. JOURNAL OF SYNCHROTRON RADIATION 2016; 23:743-750. [PMID: 27140154 DOI: 10.1107/s1600577516005464] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/01/2016] [Indexed: 06/05/2023]
Abstract
The design and operation of a low-volume spectroelectrochemical cell for X-ray absorption spectroscopy (XAS) of solutions at room temperature is described. Fluorescence XAS measurements are obtained from samples contained in the void space of a 50 µL reticulated vitreous carbon (sponge) working electrode. Both rapid electrosynthesis and control of the effects of photoreduction are achieved by control over the flow properties of the solution through the working electrode, where a good balance between the rate of consumption of sample and the minimization of decomposition was obtained by pulsing the flow of the solution by 1-2 µL with duty cycle of ∼3 s while maintaining a small net flow rate (26-100 µL h(-1)). The performance of the cell in terms of control of the redox state of the sample and minimization of the effects of photoreduction was demonstrated by XAS measurements of aqueous solutions of the photosensitive Fe(III) species, [Fe(C2O4)3](3-), together with that of the electrogenerated [Fe(C2O4)3](4-) product. The current response from the cell during the collection of XAS spectra provides an independent measure of the stability of the sample of the measurement. The suitability of the approach for the study of small volumes of mM concentrations of protein samples was demonstrated by the measurement of the oxidized and electrochemically reduced forms of cytochrome c.
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Affiliation(s)
- Stephen P Best
- School of Chemistry, University of Melbourne, Parkville, Melbourne, Victoria 3010, Australia
| | - Aviva Levina
- School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Chris Glover
- Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | - Bernt Johannessen
- Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | - Peter Kappen
- Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | - Peter A Lay
- School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
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Dickson CF, Jacques DA, Clubb RT, Guss JM, Gell DA. The structure of haemoglobin bound to the haemoglobin receptor IsdH from Staphylococcus aureus shows disruption of the native α-globin haem pocket. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2015; 71:1295-306. [PMID: 26057669 PMCID: PMC8518021 DOI: 10.1107/s1399004715005817] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 03/23/2015] [Indexed: 12/13/2022]
Abstract
Staphylococcus aureus is a common and serious cause of infection in humans. The bacterium expresses a cell-surface receptor that binds to, and strips haem from, human haemoglobin (Hb). The binding interface has previously been identified; however, the structural changes that promote haem release from haemoglobin were unknown. Here, the structure of the receptor-Hb complex is reported at 2.6 Å resolution, which reveals a conformational change in the α-globin F helix that disrupts the haem-pocket structure and alters the Hb quaternary interactions. These features suggest potential mechanisms by which the S. aureus Hb receptor induces haem release from Hb.
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Krishna Kumar K, Jacques DA, Guss JM, Gell DA. The structure of α-haemoglobin in complex with a haemoglobin-binding domain from Staphylococcus aureus reveals the elusive α-haemoglobin dimerization interface. Acta Crystallogr F Struct Biol Commun 2014; 70:1032-7. [PMID: 25084376 PMCID: PMC4118798 DOI: 10.1107/s2053230x14012175] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Accepted: 05/26/2014] [Indexed: 11/10/2022] Open
Abstract
Adult haemoglobin (Hb) is made up of two α and two β subunits. Mutations that reduce expression of the α- or β-globin genes lead to the conditions α- or β-thalassaemia, respectively. Whilst both conditions are characterized by anaemia of variable severity, other details of their pathophysiology are different, in part owing to the greater stability of the β chains that is conferred through β self-association. In contrast, α subunits interact weakly, and in the absence of stabilizing quaternary interactions the α chain (α) is prone to haem loss and denaturation. The molecular contacts that confer weak self-association of α have not been determined previously. Here, the first structure of an α2 homodimer is reported in complex with one domain of the Hb receptor from Staphylococcus aureus. The α2 dimer interface has a highly unusual, approximately linear, arrangement of four His side chains within hydrogen-bonding distance of each other. Some interactions present in the α1β1 dimer interface of native Hb are preserved in the α2 dimer. However, a marked asymmetry is observed in the α2 interface, suggesting that steric factors limit the number of stabilizing interactions that can form simultaneously across the interface.
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Affiliation(s)
- Kaavya Krishna Kumar
- School of Molecular Bioscience, University of Sydney, Sydney, NSW 2006, Australia
| | - David A. Jacques
- School of Molecular Bioscience, University of Sydney, Sydney, NSW 2006, Australia
| | - J. Mitchell Guss
- School of Molecular Bioscience, University of Sydney, Sydney, NSW 2006, Australia
| | - David A. Gell
- Menzies Research Institute, University of Tasmania, Hobart, TAS 7000, Australia
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11
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The Fe-heme structure of met-indoleamine 2,3-dioxygenase-2 determined by X-ray absorption fine structure. Biochem Biophys Res Commun 2014; 450:25-9. [DOI: 10.1016/j.bbrc.2014.05.054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 05/14/2014] [Indexed: 01/20/2023]
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12
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Koury MJ. Abnormal erythropoiesis and the pathophysiology of chronic anemia. Blood Rev 2014; 28:49-66. [PMID: 24560123 DOI: 10.1016/j.blre.2014.01.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 01/17/2014] [Indexed: 12/14/2022]
Abstract
Erythropoiesis, the bone marrow production of erythrocytes by the proliferation and differentiation of hematopoietic cells, replaces the daily loss of 1% of circulating erythrocytes that are senescent. This daily output increases dramatically with hemolysis or hemorrhage. When erythrocyte production rate of erythrocytes is less than the rate of loss, chronic anemia develops. Normal erythropoiesis and specific abnormalities of erythropoiesis that cause chronic anemia are considered during three periods of differentiation: a) multilineage and pre-erythropoietin-dependent hematopoietic progenitors, b) erythropoietin-dependent progenitor cells, and c) terminally differentiating erythroblasts. These erythropoietic abnormalities are discussed in terms of their pathophysiological effects on the bone marrow cells and the resultant changes that can be detected in the peripheral blood using a clinical laboratory test, the complete blood count.
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Affiliation(s)
- Mark J Koury
- Division of Hematology/Oncology, Vanderbilt University and Veterans Affairs Tennessee Valley Healthcare System, 777 Preston Research Building, Nashville, TN 37232, USA.
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