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Loges LN, Walstrom KM. Modeling human glucose-6-phosphate dehydrogenase mutations using C. elegans GSPD-1. MICROPUBLICATION BIOLOGY 2021; 2021:10.17912/micropub.biology.000451. [PMID: 34532700 PMCID: PMC8438584 DOI: 10.17912/micropub.biology.000451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/23/2021] [Accepted: 08/31/2021] [Indexed: 11/06/2022]
Abstract
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked, recessive condition that causes intermittent jaundice or hemolytic anemia because of low NADPH levels in red blood cells. We performed steady-state enzyme kinetics with the recombinant C. elegans ortholog of human G6PD, GSPD-1, and two mutants containing amino acid changes found in human patients. The K M values for glucose-6-phosphate were 100 ± 27 µM, 80 ± 22 µM, and 1000 ± 300 µM for the wild-type, D60N, and R252L GSPD-1 enzymes, respectively. The specific activities of the D60N and R252L mutants were 59% and 11%, respectively, of the wild-type value. Protein homology modeling suggested that the R252L mutation was more severe because the mutation caused a shift in the position of some active site residues. The D60N mutation may have affected the conformation of an outer loop of the enzyme. These data demonstrate that GSPD-1 is a promising model for human G6PD deficiencies, with the advantage that potential treatments could be studied in vivo in C. elegans.
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Affiliation(s)
- Luiza N. Loges
- Division of Natural Sciences, New College of Florida, Sarasota, FL, USA
- Currently at Dept. of Global Health, Univ. of South Florida, Tampa, FL, USA
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Gupte R, Dhagia V, Rocic P, Ochi R, Gupte SA. Glucose-6-phosphate dehydrogenase increases Ca 2+ currents by interacting with Ca v1.2 and reducing intrinsic inactivation of the L-type calcium channel. Am J Physiol Heart Circ Physiol 2020; 319:H144-H158. [PMID: 32442021 DOI: 10.1152/ajpheart.00727.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Pyridine nucleotides, such as NADPH and NADH, are emerging as critical players in the regulation of heart and vascular function. Glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme in the pentose phosphate pathway, is the primary source and regulator of cellular NADPH. In the current study, we have identified two isoforms of G6PD (slow and fast migrating) and functionally characterized the slow migrating isoform of G6PD (G6PD545) in bovine and human arteries. We found that G6PD545 is eluted in the caveolae fraction of vascular smooth muscle (VSM) and has a higher maximum rate of reaction (Vmax: 1.65-fold) than its fast migrating isoform (G6PD515). Interestingly, caveolae G6PD forms a complex with the pore-forming α1C-subunit of the L-type Ca2+ channel, Cav1.2, as demonstrated by a proximity ligation assay in fixed VSMCs. Additionally, Förster resonance energy transfer (FRET) analysis of HEK293-17T cells cotransfected with red fluorescent protein (RFP)-tagged G6PD545 (C-G6PD545) and green fluorescent protein (GFP)-tagged Cav1.2-(Cav1.2-GFP) demonstrated strong FRET signals as compared with cells cotransfected with Cav1.2-GFP and C-G6PD515. Furthermore, L-type Ca2+ channel conductance was larger and the voltage-independent component of availability (c1) was augmented in C-G6PD545 and Cav1.2-GFP cotransfectants compared with those expressing Cav1.2-GFP alone. Surprisingly, epiandrosterone, a G6PD inhibitor, disrupted the G6PD-Cav1.2 complex, also decreasing the amplitude of L-type Ca2+ currents and window currents, thereby reducing the availability of the c1 component. Moreover, overexpression of adeno-G6PD545-GFP augmented the KCl-induced contraction in coronary arteries compared with control. To determine whether overexpression of G6PD had any clinical implication, we investigated its activity in arteries from patients and rats with metabolic syndrome and found that G6PD activity was high in this disease condition. Interestingly, epiandrosterone treatment reduced elevated mean arterial blood pressure and peripheral vascular resistance in metabolic syndrome rats, suggesting that the increased activity of G6PD augmented vascular contraction and blood pressure in the metabolic syndrome. These data suggest that the novel G6PD-Cav1.2 interaction, in the caveolae fraction, reduces intrinsic voltage-dependent inactivation of the channel and contributes to regulate VSM L-type Ca2+ channel function and Ca2+ signaling, thereby playing a significant role in modulating vascular function in physiological/pathophysiological conditions.NEW & NOTEWORTHY In this study we have identified a novel isozyme of glucose-6-phosphate dehydrogenase (G6PD), a metabolic enzyme, that interacts with and contributes to regulate smooth muscle cell l-type Ca2+ ion channel function, which plays a crucial role in vascular function in physiology and pathophysiology. Furthermore, we demonstrate that expression and activity of this novel G6PD isoform are increased in arteries of individuals with metabolic syndrome and in inhibition of G6PD activity in rats of metabolic syndrome reduced blood pressure.
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Affiliation(s)
- Rakhee Gupte
- Department of Pharmacology, New York Medical College, Valhalla, New York.,Department of Biochemistry, College of Medicine, University of South Alabama, Mobile, Alabama
| | - Vidhi Dhagia
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Petra Rocic
- Department of Pharmacology, New York Medical College, Valhalla, New York.,Department of Biochemistry, College of Medicine, University of South Alabama, Mobile, Alabama
| | - Rikuo Ochi
- Department of Pharmacology, New York Medical College, Valhalla, New York.,Department of Biochemistry, College of Medicine, University of South Alabama, Mobile, Alabama
| | - Sachin A Gupte
- Department of Pharmacology, New York Medical College, Valhalla, New York.,Department of Biochemistry, College of Medicine, University of South Alabama, Mobile, Alabama
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Ai G, Dachineni R, Kumar DR, Alfonso LF, Marimuthu S, Bhat GJ. Aspirin inhibits glucose‑6‑phosphate dehydrogenase activity in HCT 116 cells through acetylation: Identification of aspirin-acetylated sites. Mol Med Rep 2016; 14:1726-32. [PMID: 27356773 PMCID: PMC4940102 DOI: 10.3892/mmr.2016.5449] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 05/18/2016] [Indexed: 12/13/2022] Open
Abstract
Glucose-6-phosphate dehydrogenase (G6PD) catalyzes the first reaction in the pentose phosphate pathway, and generates ribose sugars, which are required for nucleic acid synthesis, and nicotinamide adenine dinucleotide phosphate (NADPH), which is important for neutralization of oxidative stress. The expression of G6PD is elevated in several types of tumor, including colon, breast and lung cancer, and has been implicated in cancer cell growth. Our previous study demonstrated that exposure of HCT 116 human colorectal cancer cells to aspirin caused acetylation of G6PD, and this was associated with a decrease in its enzyme activity. In the present study, this observation was expanded to HT-29 colorectal cancer cells, in order to compare aspirin-mediated acetylation of G6PD and its activity between HCT 116 and HT-29 cells. In addition, the present study aimed to determine the acetylation targets of aspirin on recombinant G6PD to provide an insight into the mechanisms of inhibition. The results demonstrated that the extent of G6PD acetylation was significantly higher in HCT 116 cells compared with in HT-29 cells; accordingly, a greater reduction in G6PD enzyme activity was observed in the HCT 116 cells. Mass spectrometry analysis of aspirin-acetylated G6PD (isoform a) revealed that aspirin acetylated a total of 14 lysine residues, which were dispersed throughout the length of the G6PD protein. One of the important amino acid targets of aspirin included lysine 235 (K235, in isoform a) and this corresponds to K205 in isoform b, which has previously been identified as being important for catalysis. Acetylation of G6PD at several sites, including K235 (K205 in isoform b), may mediate inhibition of G6PD activity, which may contribute to the ability of aspirin to exert anticancer effects through decreased synthesis of ribose sugars and NADPH.
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Affiliation(s)
- Guoqiang Ai
- Department of Pharmaceutical Sciences, South Dakota State University College of Pharmacy, Avera Health and Sciences Center, Brookings, SD 57007, USA
| | - Rakesh Dachineni
- Department of Pharmaceutical Sciences, South Dakota State University College of Pharmacy, Avera Health and Sciences Center, Brookings, SD 57007, USA
| | - D Ramesh Kumar
- Department of Pharmaceutical Sciences, South Dakota State University College of Pharmacy, Avera Health and Sciences Center, Brookings, SD 57007, USA
| | - Lloyd F Alfonso
- D'Youville College School of Pharmacy, Buffalo, NY 14201, USA
| | - Srinivasan Marimuthu
- Department of Pharmaceutical Sciences, South Dakota State University College of Pharmacy, Avera Health and Sciences Center, Brookings, SD 57007, USA
| | - G Jayarama Bhat
- Department of Pharmaceutical Sciences, South Dakota State University College of Pharmacy, Avera Health and Sciences Center, Brookings, SD 57007, USA
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Ho HY, Cheng ML, Chiu DTY. Glucose-6-phosphate dehydrogenase--beyond the realm of red cell biology. Free Radic Res 2014; 48:1028-48. [PMID: 24720642 DOI: 10.3109/10715762.2014.913788] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Glucose-6-phosphate dehydrogenase (G6PD) is critical to the maintenance of NADPH pool and redox homeostasis. Conventionally, G6PD deficiency has been associated with hemolytic disorders. Most biochemical variants were identified and characterized at molecular level. Recently, a number of studies have shone light on the roles of G6PD in aspects of physiology other than erythrocytic pathophysiology. G6PD deficiency alters the redox homeostasis, and affects dysfunctional cell growth and signaling, anomalous embryonic development, and altered susceptibility to infection. The present article gives a brief review of basic science and clinical findings about G6PD, and covers the latest development in the field. Moreover, how G6PD status alters the susceptibility of the affected individuals to certain degenerative diseases is also discussed.
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Affiliation(s)
- H-Y Ho
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University , Kwei-san, Tao-yuan , Taiwan
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Hodge DL, Charron T, Stabile LP, Klautky SA, Salati LM. Structural characterization and tissue-specific expression of the mouse glucose-6-phosphate dehydrogenase gene. DNA Cell Biol 1998; 17:283-91. [PMID: 9539108 DOI: 10.1089/dna.1998.17.283] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Glucose-6-phosphate dehydrogenase (G6PD) activity differs among tissues and, in liver, with the dietary state of the mouse. Tissue-specific differences in G6PD activity in adipose tissue, liver, kidney, and heart were associated with similar differences in the amount of G6PD mRNA. Regulation of mRNA amount by dietary fat was only observed in liver. In mice fed a low-fat diet, the relative amounts of G6PD mRNA were 3:1:1:0.38, respectively, in the four tissues. Further, the amount of precursor mRNA for G6PD in liver, kidney, and heart reflected the amount of mature mRNA in these tissues, suggesting differing transcriptional activity. Our S1 nuclease and primer-extension analyses indicated that the same transcriptional start site is used in liver, kidney, and adipose tissue, resulting in a common 5' end of the mRNA in these tissues. Thus, differential regulation is not attributable to alternate promoter usage. A DNase hypersensitivity analysis of the 5' end of the G6PD gene identified three hypersensitive sites (HS): HS 1 and HS 2 were present in all tissues, whereas HS 3 was liver specific. Thus, regulation of G6PD expression involves both dietary and tissue-specific signals that appear to act via different mechanisms.
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Affiliation(s)
- D L Hodge
- Department of Biochemistry, West Virginia University, School of Medicine, Morgantown 26506, USA
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Turner G, Fletcher J, Elber J, Yanagawa Y, Davé V, Yoshida A. Molecular defect of a phosphoglycerate kinase variant associated with haemolytic anaemia and neurological disorders in a large kindred. Br J Haematol 1995; 91:60-5. [PMID: 7577653 DOI: 10.1111/j.1365-2141.1995.tb05245.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The X-chromosome-linked phosphoglycerate kinase (PGK) deficiency associated with severe chronic and acute haemolytic anaemia and mental disorders was first described in a large Chinese kindred in 1969. The molecular abnormality of this original variant remained to be identified. The red cell PGK activity was only about 5%, but the activity of the patients' lymphoblastoid cells was about 15% of normal. The PGK mRNA content of the patients' lymphoblastoid cells were normal. Analysis of the patients' mRNA showed the existence of a nucleotide transversion A-->T at position 491 (counting from adenine of the initiation codon). The mutation should cause an amino acid substitution Asp-->Val at position 163 of the enzyme. The replacement of the acidic aspartic acid by a hydrophobic valine is expected to induce drastic structural instability resulting in severe enzyme deficiency in the patients' tissues. The genotypes of two affected males, their mothers and 22 females of the family were identified by the PCR-mediated method using their genomic DNA samples. 13/24 females examined were found to be variant heterozygous. In this large family, affected males over three generations have died at a pre-adult age. Post- and pre-natal genotyping of the family members may prevent future problems.
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Affiliation(s)
- G Turner
- Prince of Wales Children's Hospital, Sydney, Australia
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