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Mathai C, Jourd'heuil F, Pham LGC, Gilliard K, Balnis J, Jen A, Overmyer KA, Coon JJ, Jaitovich A, Boivin B, Jourd'heuil D. A role for cytoglobin in regulating intracellular hydrogen peroxide and redox signals in the vasculature. bioRxiv 2023:2023.03.31.535146. [PMID: 37034694 PMCID: PMC10081330 DOI: 10.1101/2023.03.31.535146] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The oxidant hydrogen peroxide serves as a signaling molecule that alters many aspects of cardiovascular functions. Recent studies suggest that cytoglobin - a hemoglobin expressed in the vasculature - may promote electron transfer reactions with proposed functions in hydrogen peroxide decomposition. Here, we determined the extent to which cytoglobin regulates intracellular hydrogen peroxide and established mechanisms. We found that cytoglobin decreased the hyperoxidation of peroxiredoxins and maintained the activity of peroxiredoxin 2 following challenge with exogenous hydrogen peroxide. Cytoglobin promoted a reduced intracellular environment and facilitated the reduction of the thiol-based hydrogen peroxide sensor Hyper7 after bolus addition of hydrogen peroxide. Cytoglobin also limited the inhibitory effect of hydrogen peroxide on glycolysis and reversed the oxidative inactivation of the glycolytic enzyme GAPDH. Our results indicate that cytoglobin in cells exists primarily as oxyferrous cytoglobin (CygbFe 2+ -O 2 ) with its cysteine residues in the reduced form. We found that the specific substitution of one of two cysteine residues on cytoglobin (C83A) inhibited the reductive activity of cytoglobin on Hyper7 and GAPDH. Carotid arteries from cytoglobin knockout mice were more sensitive to glycolytic inhibition by hydrogen peroxide than arteries from wildtype mice. Together, these results support a role for cytoglobin in regulating intracellular redox signals associated with hydrogen peroxide through oxidation of its cysteine residues, independent of hydrogen peroxide reaction at its heme center.
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Mathai C, Jourd'heuil F, Pham LGC, Gilliard K, Howard D, Balnis J, Jaitovich A, Chittur SV, Rilley M, Peredo-Wende R, Ammoura I, Shin SJ, Barroso M, Barra J, Shishkova E, Coon JJ, Lopez-Soler RI, Jourd'heuil D. Regulation of DNA damage and transcriptional output in the vasculature through a cytoglobin-HMGB2 axis. Redox Biol 2023; 65:102838. [PMID: 37573836 PMCID: PMC10428073 DOI: 10.1016/j.redox.2023.102838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 07/24/2023] [Accepted: 08/02/2023] [Indexed: 08/15/2023] Open
Abstract
Identifying novel regulators of vascular smooth muscle cell function is necessary to further understand cardiovascular diseases. We previously identified cytoglobin, a hemoglobin homolog, with myogenic and cytoprotective roles in the vasculature. The specific mechanism of action of cytoglobin is unclear but does not seem to be related to oxygen transport or storage like hemoglobin. Herein, transcriptomic profiling of injured carotid arteries in cytoglobin global knockout mice revealed that cytoglobin deletion accelerated the loss of contractile genes and increased DNA damage. Overall, we show that cytoglobin is actively translocated into the nucleus of vascular smooth muscle cells through a redox signal driven by NOX4. We demonstrate that nuclear cytoglobin heterodimerizes with the non-histone chromatin structural protein HMGB2. Our results are consistent with a previously unknown function by which a non-erythrocytic hemoglobin inhibits DNA damage and regulates gene programs in the vasculature by modulating the genome-wide binding of HMGB2.
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Affiliation(s)
- Clinton Mathai
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA
| | - Frances Jourd'heuil
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA
| | - Le Gia Cat Pham
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA
| | - Kurrim Gilliard
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA
| | - Dennis Howard
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA
| | - Joseph Balnis
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA; Division of Pulmonary and Critical Care Medicine, Albany Medical College, Albany, NY, USA
| | - Ariel Jaitovich
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA; Division of Pulmonary and Critical Care Medicine, Albany Medical College, Albany, NY, USA
| | - Sridar V Chittur
- Center for Functional Genomics, Cancer Research Center, University at Albany, New York, 12144, USA
| | - Mark Rilley
- Division of Rheumatology, Department of Medicine, Samuel Stratton VA Medical Center, Albany, NY, 12208, USA
| | - Ruben Peredo-Wende
- Division of Rheumatology, Department of Medicine, Samuel Stratton VA Medical Center, Albany, NY, 12208, USA
| | - Ibrahim Ammoura
- Department of Pathology and Medicine, Albany Medical Center, Albany, NY, 12208, USA
| | - Sandra J Shin
- Department of Pathology and Medicine, Albany Medical Center, Albany, NY, 12208, USA
| | - Margarida Barroso
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA
| | - Jonathan Barra
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA
| | - Evgenia Shishkova
- National Center for Quantitative Biology of Complex Systems, Madison, WI, 53706, USA; Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53506, USA
| | - Joshua J Coon
- Department of Pathology and Medicine, Albany Medical Center, Albany, NY, 12208, USA; Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53506, USA; Morgridge Institute for Research, Madison, WI, 53515, USA; Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53506, USA
| | - Reynold I Lopez-Soler
- Section of Renal Transplantation, Edward Hines VA Jr. Hospital, Hines, IL, 60141, USA; Department of Surgery, Division of Intra-Abdominal Transplantation, Stritch School of Medicine, Maywood, IL, 60153, USA
| | - David Jourd'heuil
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA.
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Mathai C, Jourd'heuil F, Pham LGC, Gilliard K, Howard D, Balnis J, Jaitovich A, Chittur SV, Rilley M, Peredo-Wende R, Ammoura I, Shin SJ, Barroso M, Barra J, Shishkova E, Coon JJ, Lopez-Soler RI, Jourd'heuil D. Nuclear cytoglobin associates with HMGB2 and regulates DNA damage and genome-wide transcriptional output in the vasculature. bioRxiv 2023:2023.05.10.540045. [PMID: 37214992 PMCID: PMC10197644 DOI: 10.1101/2023.05.10.540045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Identifying novel regulators of vascular smooth muscle cell function is necessary to further understand cardiovascular diseases. We previously identified cytoglobin, a hemoglobin homolog, with myogenic and cytoprotective roles in the vasculature. The specific mechanism of action of cytoglobin is unclear but does not seem to be related to oxygen transport or storage like hemoglobin. Herein, transcriptomic profiling of injured carotid arteries in cytoglobin global knockout mice revealed that cytoglobin deletion accelerated the loss of contractile genes and increased DNA damage. Overall, we show that cytoglobin is actively translocated into the nucleus of vascular smooth muscle cells through a redox signal driven by NOX4. We demonstrate that nuclear cytoglobin heterodimerizes with the non-histone chromatin structural protein HMGB2. Our results are consistent with a previously unknown function by which a non-erythrocytic hemoglobin inhibits DNA damage and regulates gene programs in the vasculature by modulating the genome-wide binding of HMGB2.
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Jain RK, Lee E, Mathai C, Dako F, Gogineni P, Weiner MG, Vokes T. Using opportunistic screening with abdominal CT to identify osteoporosis and osteopenia in patients with diabetes. Osteoporos Int 2020; 31:2189-2196. [PMID: 32623489 DOI: 10.1007/s00198-020-05521-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 06/25/2020] [Indexed: 12/11/2022]
Abstract
UNLABELLED Opportunistic osteoporosis screening involves measuring the attenuation of L1 vertebrae on abdominal computed tomography (CT), which correlates with DXA T-score. We found that this approach is useful for detecting low bone mass in patients with diabetes and propose L1 attenuation ≤ 135 Hounsfield units (HU) as a threshold for which DXA should be strongly considered. INTRODUCTION Attenuation of the L1 vertebrae on computer tomography (CT) images done for other reasons ("Opportunistic Osteoporosis Screening") has been found to correlate well with DXA-derived T-score. However, the method and the thresholds have never been tested specifically in those with diabetes mellitus (DM), in whom the fracture risk is greater than explained by BMD. METHODS In a retrospective study of subjects with DM who had both abdominal CT and DXA within 6 months of each other, we compared L1 attenuation and DXA T-score to define the sensitivity and specificity of thresholds previously established in the general population. RESULTS There were 313 subjects among whom 18 (5.8%) had prior major osteoporotic fracture (MOF). Subjects with MOF had lower T-scores (- 2.3 ± 1.4 vs. - 0.9 ± 1.4, p < 0.001) and L1 attenuation (104 HU ± 46 vs. 149 HU ± 47, p < 0.001) than non-fracture subjects. L1 attenuation ≤ 160 HU was 91% sensitive for osteoporosis, while ≤ 110 HU was 80% specific. For a higher T-score of ≤ - 1.5, L1 attenuation ≤ 135 HU showed balanced sensitivity and specificity (65% and 69%, respectively). CONCLUSION Opportunistic osteoporosis screening with abdominal CT is useful in determining the need for DXA screening in subjects with diabetes. We propose L1 attenuation ≤ 135 HU as a reasonable threshold for detecting the T-score of ≤ - 1.5, which is likely associated with increased fragility in DM.
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Affiliation(s)
- R K Jain
- Section of Endocrinology, Diabetes, and Metabolism, Lewis Katz School of Medicine at Temple University, 3322 N Broad St, Ste 205, Philadelphia, PA, 19140, USA.
| | - E Lee
- Lewis Katz School of Medicine at Temple University, Philadelphia, PA, 19140, USA
| | - C Mathai
- Section of Endocrinology, Diabetes, and Metabolism, Temple University Hospital, Philadelphia, PA, 19140, USA
| | - F Dako
- Department of Radiology, University of Maryland Medical Center, Baltimore, MD, 21201, USA
| | - P Gogineni
- Section of Endocrinology, Diabetes, and Metabolism, Temple University Hospital, Philadelphia, PA, 19140, USA
| | - M G Weiner
- Department of Healthcare Policy and Research, Weill Cornell Medicine, New York, NY, 10038, USA
| | - T Vokes
- Department of Medicine, Section of Endocrinology, Diabetes, and Metabolism, The University of Chicago, Chicago, IL, 60637, USA
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Mathai C, Jourd'heuil FL, Lopez-Soler RI, Jourd'heuil D. Emerging perspectives on cytoglobin, beyond NO dioxygenase and peroxidase. Redox Biol 2020; 32:101468. [PMID: 32087552 PMCID: PMC7033357 DOI: 10.1016/j.redox.2020.101468] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/05/2020] [Accepted: 02/13/2020] [Indexed: 12/18/2022] Open
Abstract
Cytoglobin is an evolutionary ancient hemoglobin with poor functional annotation. Rather than constrained to penta coordination, cytoglobin's heme iron may exist either as a penta or hexacoordinated arrangement when exposed to different intracellular environments. Two cysteine residues at the surface of the protein form an intramolecular disulfide bond that regulates iron coordination, ligand binding, and peroxidase activity. Overall, biochemical results do not support a role for cytoglobin as a direct antioxidant enzyme that scavenges hydrogen peroxide because the rate of the reaction of cytoglobin with hydrogen peroxide is several orders of magnitude slower than metal and thiol-based peroxidases. Thus, alternative substrates such as fatty acids have been suggested and regulation of nitric oxide bioavailability through nitric oxide dioxygenase and nitrite reductase activities has received experimental support. Cytoglobin is broadly expressed in connective, muscle, and nervous tissues. Rational for differential cellular distribution is poorly understood but inducibility in response to hypoxia is one of the most established features of cytoglobin expression with regulation through the transcription factor hypoxia-inducible factor (HIF). Phenotypic characterization of cytoglobin deletion in the mouse have indicated broad changes that include a heightened inflammatory response and fibrosis, increase tumor burden, cardiovascular dysfunction, and hallmarks of senescence. Some of these changes might be reversed upon inhibition of nitric oxide synthase. However, subcellular and molecular interactions have been seldom characterized. In addition, specific molecular mechanisms of action are still lacking. We speculate that cytoglobin functionality will extend beyond nitric oxide handling and will have to encompass indirect regulatory antioxidant and redox sensing functions.
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Affiliation(s)
- Clinton Mathai
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA
| | - Frances L Jourd'heuil
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA
| | | | - David Jourd'heuil
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA.
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Mathai C, Jain R, Achanta VG, Duttagupta SP, Ghindani D, Joshi NR, Pinto R, Prabhu SS. Sensing at terahertz frequency domain using a sapphire whispering gallery mode resonator. Opt Lett 2018; 43:5383-5386. [PMID: 30383013 DOI: 10.1364/ol.43.005383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 10/08/2018] [Indexed: 06/08/2023]
Abstract
In this Letter, we experimentally demonstrate a terahertz (THz) whispering gallery mode (WGM) sensor based on a sapphire WGM resonator. The fundamental mode at 129.49 GHz with a Q-factor of 4.63×103 is used to study its sensitivity to adsorbed molecules. The efficiency of our sensor to detect rhodamine 6G dye molecules in a polyvinyl alcohol matrix at room temperature has been manifested, and a detection sensitivity of 25 parts per million has been achieved. Also, we report an analytical approach based on coupled-mode theory between the waveguide mode and the spherical resonator mode to evaluate the absorption coefficient of the adsorbed molecule on the resonator. The model is modified to evaluate optical constants of materials. The results obtained have been verified by continuous-wave THz transmission results. The results are of importance in sensing, metrology, and material characterization.
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