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Jeyaraju DV, Alapa M, Polonskaia A, Risueño A, Subramanyam P, Anand A, Ghosh K, Kyriakopoulos C, Hemerich D, Hurren R, Wang X, Gronda M, Ahsan A, Chiu H, Thomas G, Lind EF, Menezes DL, Schimmer AD, Hagner PR, Gandhi A, Thakurta AG. Extended exposure to low doses of azacitidine induces differentiation of leukemic stem cells through activation of myeloperoxidase. Haematologica 2024; 109:1082-1094. [PMID: 37941406 PMCID: PMC10985425 DOI: 10.3324/haematol.2023.283437] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 10/30/2023] [Indexed: 11/10/2023] Open
Abstract
Oral azacitidine (oral-Aza) treatment results in longer median overall survival (OS) (24.7 vs. 14.8 months in placebo) in patients with acute myeloid leukemia (AML) in remission after intensive chemotherapy. The dosing schedule of oral-Aza (14 days/28-day cycle) allows for low exposure of Aza for an extended duration thereby facilitating a sustained therapeutic effect. However, the underlying mechanisms supporting the clinical impact of oral-Aza in maintenance therapy remain to be fully understood. In this preclinical work, we explore the mechanistic basis of oral-Aza/extended exposure to Aza through in vitro and in vivo modeling. In cell lines, extended exposure to Aza results in sustained DNMT1 loss, leading to durable hypomethylation, and gene expression changes. In mouse models, extended exposure to Aza, preferentially targets immature leukemic cells. In leukemic stem cell (LSC) models, the extended dose of Aza induces differentiation and depletes CD34+CD38- LSC. Mechanistically, LSC differentiation is driven in part by increased myeloperoxidase (MPO) expression. Inhibition of MPO activity either by using an MPO-specific inhibitor or blocking oxidative stress, a known mechanism of MPO, partly reverses the differentiation of LSC. Overall, our preclinical work reveals novel mechanistic insights into oral-Aza and its ability to target LSC.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Rose Hurren
- Princess Margaret Cancer Centre, Toronto, ON
| | | | | | | | | | | | - Evan F Lind
- Department of Molecular Microbiology and the Knight Cancer Institute, Oregon Health and Science University, Portland, OR
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Alapa M, Cui C, Shu P, Li H, Kholodovych V, Beuve A. Selective cysteines oxidation in soluble guanylyl cyclase catalytic domain is involved in NO activation. Free Radic Biol Med 2021; 162:450-460. [PMID: 33161042 PMCID: PMC7889651 DOI: 10.1016/j.freeradbiomed.2020.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 10/30/2020] [Accepted: 11/01/2020] [Indexed: 12/18/2022]
Abstract
Nitric oxide (NO) binds to soluble guanylyl cyclase (GC1) and stimulates its catalytic activity to produce cGMP. Despite the key role of the NO-cGMP signaling in cardiovascular physiology, the mechanisms of GC1 activation remain ill-defined. It is believed that conserved cysteines (Cys) in GC1 modulate the enzyme's activity through thiol-redox modifications. We previously showed that GC1 activity is modulated via mixed-disulfide bond by protein disulfide isomerase and thioredoxin 1. Herein we investigated the novel concept that NO-stimulated GC1 activity is mediated by thiol/disulfide switches and aimed to map the specific Cys that are involved. First, we showed that the dithiol reducing agent Tris (2-carboxyethyl)-phosphine reduces GC1 response to NO, indicating the significance of Cys oxidation in NO activation. Second, using dibromobimane, which fluoresces when crosslinking two vicinal Cys thiols, we demonstrated decreased fluorescence in NO-stimulated GC1 compared to unstimulated conditions. This suggested that NO-stimulated GC1 contained more bound Cys, potentially disulfide bonds. Third, to identify NO-regulated Cys oxidation using mass spectrometry, we compared the redox status of all Cys identified in tryptic peptides, among which, ten were oxidized and two were reduced in NO-stimulated GC1. Fourth, we resorted to computational modeling to narrow down the Cys candidates potentially involved in disulfide bond and identified Cys489 and Cys571. Fifth, our mutational studies showed that Cys489 and Cys571 were involved in GC1'response to NO, potentially as a thiol/disulfide switch. These findings imply that specific GC1 Cys sensitivity to redox environment is critical for NO signaling in cardiovascular physiology.
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Affiliation(s)
- Maryam Alapa
- Department of Pharmacology, Physiology, and Neuroscience, New Jersey Medical School-Rutgers, Newark, NJ, 07103, USA
| | - Chuanlong Cui
- Department of Pharmacology, Physiology, and Neuroscience, New Jersey Medical School-Rutgers, Newark, NJ, 07103, USA; Center for Advanced Proteomics Research- New Jersey Medical School- Rutgers, Newark, NJ, 07103, USA
| | - Ping Shu
- Department of Pharmacology, Physiology, and Neuroscience, New Jersey Medical School-Rutgers, Newark, NJ, 07103, USA
| | - Hong Li
- Center for Advanced Proteomics Research- New Jersey Medical School- Rutgers, Newark, NJ, 07103, USA
| | - Vlad Kholodovych
- Office of Advanced Research Computing, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Annie Beuve
- Department of Pharmacology, Physiology, and Neuroscience, New Jersey Medical School-Rutgers, Newark, NJ, 07103, USA.
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Cui C, Alapa M, Shu P, Kholodovych V, Li H, Beuve AV. Abstract 869: Cysteine-based Redox Regulation of Soluble Guanylyl Cyclase. Circ Res 2019. [DOI: 10.1161/res.125.suppl_1.869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Soluble guanylyl cyclase (GC1) is the major receptor of nitric oxide (NO) and a key regulator for cardiovascular physiology. NO binding to the heme of GC1 catalyzes conversion of GTP to cGMP, which in turn activates protein kinase G pathway, thus leading to vasodilation. However, the mechanism by which NO signaling is propagated within the GC1 molecule for its stimulation is still poorly understood. The high frequency of solvent-exposed cysteines (Cys) of GC1 suggests a potential role of Cys posttranslational modifications (PTMs) in regulating GC1 activity. Our previous studies show that the disulfide reductase Thioredoxin 1 (Trx1) can interact with GC1 and affect its activity in cells. Together with studies showing that GC1 activity is modulated by thiol redox, we hypothesize that thiol/disulfide switch might be a mechanism that regulates the activity of GC1. Here we show that dithiol oxidant diamide can dose-dependently affect the activity of GC1. PEG-switch assay, LC/MS/MS and mutational analysis identified Cys involved in redox regulation of GC1. In addition, we show that Trx1 modulates Cys-based redox PTMs of GC1 in cells and blocking the interaction between Trx1 and GC1 affects GC1 activity in a purified system. Taken together, these results suggest that the thiol/disulfide switch of GC1 and its interaction with Trx1 could be an underlying mechanism for NO stimulation of GC1.
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Affiliation(s)
| | - Maryam Alapa
- Rutgers Univ Sch of Graduate Studies, Newark, NJ
| | - Ping Shu
- Rutgers Univ New Jersey Med Sch, Newark, NJ
| | | | - Hong Li
- Rutgers Univ New Jersey Med Sch, Newark, NJ
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Huang C, Alapa M, Shu P, Nagarajan N, Wu C, Sadoshima J, Kholodovych V, Li H, Beuve A. Guanylyl cyclase sensitivity to nitric oxide is protected by a thiol oxidation-driven interaction with thioredoxin-1. J Biol Chem 2017; 292:14362-14370. [PMID: 28659344 DOI: 10.1074/jbc.m117.787390] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 06/20/2017] [Indexed: 01/08/2023] Open
Abstract
Nitric oxide (NO) modulates many physiological events through production of cGMP from its receptor, the NO-sensitive guanylyl cyclase (GC1). NO also appears to function in a cGMP-independent manner, via S-nitrosation (SNO), a redox-based modification of cysteine thiols. Previously, we have shown that S-nitrosated GC1 (SNO-GC1) is desensitized to NO stimulation following prolonged NO exposure or under oxidative/nitrosative stress. In animal models of nitrate tolerance and angiotensin II-induced hypertension, decreased vasodilation in response to NO correlates with GC1 thiol oxidation, but the physiological mechanism that resensitizes GC1 to NO and restores basal activity is unknown. Because GC1 interacts with the oxidoreductase protein-disulfide isomerase, we hypothesized that thioredoxin-1 (Trx1), a cytosolic oxidoreductase, could be involved in restoring GC1 basal activity and NO sensitivity because the Trx/thioredoxin reductase (TrxR) system maintains thiol redox homeostasis. Here, by manipulating activity and levels of the Trx1/TrxR system and by using a Trx1-Trap assay, we demonstrate that Trx1 modulates cGMP synthesis through an association between Trx1 and GC1 via a mixed disulfide. A proximity ligation assay confirmed the endogenous Trx1-GC1 complex in cells. Mutational analysis suggested that Cys609 in GC1 is involved in the Trx1-GC1 association and modulation of GC1 activity. Functionally, we established that Trx1 protects GC1 from S-nitrosocysteine-induced desensitization. A computational model of Trx1-GC1 interaction illustrates a possible mechanism for Trx1 to maintain basal GC1 activity and prevent/rescue GC1 desensitization to NO. The etiology of some oxidative vascular diseases may very well be explained by the dysfunction of the Trx1-GC1 association.
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Affiliation(s)
- Can Huang
- From the Department of Pharmacology, Physiology, and Neuroscience
| | - Maryam Alapa
- From the Department of Pharmacology, Physiology, and Neuroscience
| | - Ping Shu
- From the Department of Pharmacology, Physiology, and Neuroscience
| | - Narayani Nagarajan
- the Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark, New Jersey 07103
| | - Changgong Wu
- the Center for Advanced Proteomics Research, Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers New Jersey Medical School Cancer Center, Newark, New Jersey 07103
| | - Junichi Sadoshima
- the Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark, New Jersey 07103
| | - Vladyslav Kholodovych
- the Office of Advanced and Research Computing, Rutgers University, Piscataway, New Jersey 08854, and.,the Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey 08901
| | - Hong Li
- the Center for Advanced Proteomics Research, Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers New Jersey Medical School Cancer Center, Newark, New Jersey 07103
| | - Annie Beuve
- From the Department of Pharmacology, Physiology, and Neuroscience,
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