1
|
Ward AS, Hsiung CH, Kesterson DG, Kamath VG, McKee EE. Entecavir competitively inhibits deoxyguanosine and deoxyadenosine phosphorylation in isolated mitochondria and the perfused rat heart. J Biol Chem 2022; 298:101876. [PMID: 35358513 PMCID: PMC9097457 DOI: 10.1016/j.jbc.2022.101876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/21/2022] [Accepted: 03/24/2022] [Indexed: 10/26/2022] Open
Abstract
Deoxyguanosine kinase (dGK) is reported responsible for the phosphorylation of deoxyadenosine (dA) and deoxyguanosine (dG) in the mitochondrial purine salvage pathway. Antiviral nucleoside analogs known as nucleoside reverse transcriptase inhibitors (NRTIs) must be phosphorylated by host enzymes for the analog to become active. We address the possibility that NRTI purine analogs may be competitive inhibitors of dGK. From a group of such analogs, we demonstrate that entecavir (ETV) competitively inhibited the phosphorylation of dG and dA in rat mitochondria. Mitochondria from the brain, heart, kidney, and liver showed a marked preference for phosphorylation of dG over dA (10-30-fold) and ETV over dA (2.5-4-fold). We found that ETV inhibited the phosphorylation of dG with an IC50 of 15.3 ± 2.2 μM and that ETV and dG were both potent inhibitors of dA phosphorylation with IC50s of 0.034 ± 0.007 and 0.028 ± 0.006 μM, respectively. In addition, the phosphorylation of dG and ETV followed Michaelis-Menten kinetics and each competitively inhibited the phosphorylation of the other. We observed that the kinetics of dA phosphorylation were strikingly different from those of dG phosphorylation, with an exponentially lower affinity for dGK and no effect of dA on dG or ETV phosphorylation. Finally, in an isolated heart perfusion model, we demonstrated that dG, dA, and ETV were phosphorylated and dG phosphorylation was inhibited by ETV. Taken together, these data demonstrate that dGK is inhibited by ETV and that the primary role of dGK is in the phosphorylation of dG rather than dA.
Collapse
Affiliation(s)
- Avery S Ward
- Department of Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, Michigan, USA
| | - Chia-Heng Hsiung
- Department of Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, Michigan, USA; School of Science, Westlake Institute for Advanced Study, Westlake University, Hangzhou, Zhejiang Province, China
| | - Daniel G Kesterson
- Department of Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, Michigan, USA; Department of Health Management and Policy, University of Michigan School of Public Health, University of Michigan, Ann Arbor, Michigan, USA
| | - Vasudeva G Kamath
- Department of Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, Michigan, USA; Department of Basic Medical Sciences, Touro College of Osteopathic Medicine, Middletown, New York, USA
| | - Edward E McKee
- Department of Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, Michigan, USA.
| |
Collapse
|
2
|
Di Pasqua LG, Cagna M, Berardo C, Vairetti M, Ferrigno A. Detailed Molecular Mechanisms Involved in Drug-Induced Non-Alcoholic Fatty Liver Disease and Non-Alcoholic Steatohepatitis: An Update. Biomedicines 2022; 10:194. [PMID: 35052872 PMCID: PMC8774221 DOI: 10.3390/biomedicines10010194] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 12/12/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are some of the biggest public health challenges due to their spread and increasing incidence around the world. NAFLD is characterized by intrahepatic lipid deposition, accompanied by dyslipidemia, hypertension, and insulin resistance, leading to more serious complications. Among the various causes, drug administration for the treatment of numerous kinds of diseases, such as antiarrhythmic and antihypertensive drugs, promotes the onset and progression of steatosis, causing drug-induced hepatic steatosis (DIHS). Here, we reviewed in detail the major classes of drugs that cause DIHS and the specific molecular mechanisms involved in these processes. Eight classes of drugs, among the most used for the treatment of common pathologies, were considered. The most diffused mechanism whereby drugs can induce NAFLD/NASH is interfering with mitochondrial activity, inhibiting fatty acid oxidation, but other pathways involved in lipid homeostasis are also affected. PubMed research was performed to obtain significant papers published up to November 2021. The key words included the class of drugs, or the specific compound, combined with steatosis, nonalcoholic steatohepatitis, fibrosis, fatty liver and hepatic lipid deposition. Additional information was found in the citations listed in other papers, when they were not displayed in the original search.
Collapse
Affiliation(s)
- Laura Giuseppina Di Pasqua
- Unit of Cellular and Molecular Pharmacology and Toxicology, Department of Internal Medicine and Therapeutics, University of Pavia, 27100 Pavia, Italy
| | - Marta Cagna
- Unit of Cellular and Molecular Pharmacology and Toxicology, Department of Internal Medicine and Therapeutics, University of Pavia, 27100 Pavia, Italy
| | - Clarissa Berardo
- Unit of Cellular and Molecular Pharmacology and Toxicology, Department of Internal Medicine and Therapeutics, University of Pavia, 27100 Pavia, Italy
| | - Mariapia Vairetti
- Unit of Cellular and Molecular Pharmacology and Toxicology, Department of Internal Medicine and Therapeutics, University of Pavia, 27100 Pavia, Italy
| | - Andrea Ferrigno
- Unit of Cellular and Molecular Pharmacology and Toxicology, Department of Internal Medicine and Therapeutics, University of Pavia, 27100 Pavia, Italy
| |
Collapse
|
3
|
Yuan NY, Kaul M. Beneficial and Adverse Effects of cART Affect Neurocognitive Function in HIV-1 Infection: Balancing Viral Suppression against Neuronal Stress and Injury. J Neuroimmune Pharmacol 2021; 16:90-112. [PMID: 31385157 PMCID: PMC7233291 DOI: 10.1007/s11481-019-09868-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 07/23/2019] [Indexed: 02/07/2023]
Abstract
HIV-associated neurocognitive disorders (HAND) persist despite the successful introduction of combination antiretroviral therapy (cART). While insufficient concentration of certain antiretrovirals (ARV) may lead to incomplete viral suppression in the brain, many ARVs are found to cause neuropsychiatric adverse effects, indicating their penetration into the central nervous system (CNS). Several lines of evidence suggest shared critical roles of oxidative and endoplasmic reticulum stress, compromised neuronal energy homeostasis, and autophagy in the promotion of neuronal dysfunction associated with both HIV-1 infection and long-term cART or ARV use. As the lifespans of HIV patients are increased, unique challenges have surfaced. Longer lives convey prolonged exposure of the CNS to viral toxins, neurotoxic ARVs, polypharmacy with prescribed or illicit drug use, and age-related diseases. All of these factors can contribute to increased risks for the development of neuropsychiatric conditions and cognitive impairment, which can significantly impact patient well-being, cART adherence, and overall health outcome. Strategies to increase the penetration of cART into the brain to lower viral toxicity may detrimentally increase ARV neurotoxicity and neuropsychiatric adverse effects. As clinicians attempt to control peripheral viremia in an aging population of HIV-infected patients, they must navigate an increasingly complex myriad of comorbidities, pharmacogenetics, drug-drug interactions, and psychiatric and cognitive dysfunction. Here we review in comparison to the neuropathological effects of HIV-1 the available information on neuropsychiatric adverse effects and neurotoxicity of clinically used ARV and cART. It appears altogether that future cART aiming at controlling HIV-1 in the CNS and preventing HAND will require an intricate balancing act of suppressing viral replication while minimizing neurotoxicity, impairment of neurocognition, and neuropsychiatric adverse effects. Graphical abstract Schematic summary of the effects exerted on the brain and neurocognitive function by HIV-1 infection, comorbidities, psychostimulatory, illicit drugs, therapeutic drugs, such as antiretrovirals, the resulting polypharmacy and aging, as well as the potential interactions of all these factors.
Collapse
Affiliation(s)
- Nina Y Yuan
- School of Medicine, Division of Biomedical Sciences, University of California Riverside, 900 University Ave, Riverside, CA, 92521, USA
| | - Marcus Kaul
- School of Medicine, Division of Biomedical Sciences, University of California Riverside, 900 University Ave, Riverside, CA, 92521, USA.
- Sanford Burnham Prebys Medical Discovery Institute, Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Road, La Jolla, CA, 92037, USA.
| |
Collapse
|
4
|
Fraik AK, Margres MJ, Epstein B, Barbosa S, Jones M, Hendricks S, Schönfeld B, Stahlke AR, Veillet A, Hamede R, McCallum H, Lopez-Contreras E, Kallinen SJ, Hohenlohe PA, Kelley JL, Storfer A. Disease swamps molecular signatures of genetic-environmental associations to abiotic factors in Tasmanian devil (Sarcophilus harrisii) populations. Evolution 2020; 74:1392-1408. [PMID: 32445281 DOI: 10.1111/evo.14023] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 05/14/2020] [Indexed: 12/11/2022]
Abstract
Landscape genomics studies focus on identifying candidate genes under selection via spatial variation in abiotic environmental variables, but rarely by biotic factors (i.e., disease). The Tasmanian devil (Sarcophilus harrisii) is found only on the environmentally heterogeneous island of Tasmania and is threatened with extinction by a transmissible cancer, devil facial tumor disease (DFTD). Devils persist in regions of long-term infection despite epidemiological model predictions of species' extinction, suggesting possible adaptation to DFTD. Here, we test the extent to which spatial variation and genetic diversity are associated with the abiotic environment (i.e., climatic variables, elevation, vegetation cover) and/or DFTD. We employ genetic-environment association analyses using 6886 SNPs from 3287 individuals sampled pre- and post-disease arrival across the devil's geographic range. Pre-disease, we find significant correlations of allele frequencies with environmental variables, including 365 unique loci linked to 71 genes, suggesting local adaptation to abiotic environment. The majority of candidate loci detected pre-DFTD are not detected post-DFTD arrival. Several post-DFTD candidate loci are associated with disease prevalence and were in linkage disequilibrium with genes involved in tumor suppression and immune response. Loss of apparent signal of abiotic local adaptation post-disease suggests swamping by strong selection resulting from the rapid onset of DFTD.
Collapse
Affiliation(s)
- Alexandra K Fraik
- School of Biological Sciences, Washington State University, Pullman, Washington, 99164
| | - Mark J Margres
- School of Biological Sciences, Washington State University, Pullman, Washington, 99164
| | - Brendan Epstein
- School of Biological Sciences, Washington State University, Pullman, Washington, 99164.,Plant Biology, University of Minnesota, Minneapolis, Minnesota, 55455
| | - Soraia Barbosa
- Department of Biological Sciences, Institute for Bioinformatics and Evolutionary Studies, University of Idaho, 875 Perimeter Drive, Moscow, Idaho, 83844
| | - Menna Jones
- School of Biological Sciences, University of Tasmania, Hobart, TAS, 7004, Australia
| | - Sarah Hendricks
- Department of Biological Sciences, Institute for Bioinformatics and Evolutionary Studies, University of Idaho, 875 Perimeter Drive, Moscow, Idaho, 83844
| | - Barbara Schönfeld
- School of Biological Sciences, University of Tasmania, Hobart, TAS, 7004, Australia
| | - Amanda R Stahlke
- Department of Biological Sciences, Institute for Bioinformatics and Evolutionary Studies, University of Idaho, 875 Perimeter Drive, Moscow, Idaho, 83844
| | - Anne Veillet
- Department of Biological Sciences, Institute for Bioinformatics and Evolutionary Studies, University of Idaho, 875 Perimeter Drive, Moscow, Idaho, 83844
| | - Rodrigo Hamede
- School of Biological Sciences, University of Tasmania, Hobart, TAS, 7004, Australia
| | - Hamish McCallum
- School of Environment, Griffith University Nathan, Nathan, QLD, 4111, Australia
| | - Elisa Lopez-Contreras
- School of Biological Sciences, Washington State University, Pullman, Washington, 99164
| | - Samantha J Kallinen
- School of Biological Sciences, Washington State University, Pullman, Washington, 99164
| | - Paul A Hohenlohe
- Department of Biological Sciences, Institute for Bioinformatics and Evolutionary Studies, University of Idaho, 875 Perimeter Drive, Moscow, Idaho, 83844
| | - Joanna L Kelley
- School of Biological Sciences, Washington State University, Pullman, Washington, 99164
| | - Andrew Storfer
- School of Biological Sciences, Washington State University, Pullman, Washington, 99164
| |
Collapse
|
5
|
Sun R, Eriksson S, Wang L. The expression and activity of thymidine kinase 1 and deoxycytidine kinase are modulated by hydrogen peroxide and nucleoside analogs. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2020; 39:1347-1358. [PMID: 32189555 DOI: 10.1080/15257770.2020.1720234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Thymidine kinase 1 (TK1) and deoxycytidine kinase (dCK) are required for the activation of thymidine and deoxycytidine analogs used in antiviral and anticancer therapies. Many anticancer drugs cause oxidative stress, and the rise of GSSG and other reactive oxygen species may lead to alteration in gene expression, protein, nucleic acids and lipid modifications. Here, we investigated the effects of oxidative stress and nucleoside analog on the expression and activity of TK1 and dCK. Treatment with GSSG resulted in glutathionylation of dCK and dGK but not TK1 and Dm-dNK, and glutathionylation led to increased dCK activity but decreased dGK activity. Treatment with hydrogen peroxide resulted in induction of TK1, however, the TK1 activity did not correlate with TK1 protein levels, indicating that TK1 protein was inactive. The cellular expression of dCK, however, was reduced but dCK activity was not affected at concentration ≤ 4 mM. Treatment with TFT or 5FdU resulted in downregulation of both TK1 and dCK. However, araC and dFdC treatment led to increased dCK protein but decreased dCK activity. In contrast, both TK1 protein and activity were upregulated after araC and dFdC treatment. Doxorubicin treatment led to upregulation of the TK1 but downregulation of dCK. In conclusion TK1 and dCK expression and activity are apparently affected by oxidative stress and treatment by nucleoside analogs. These results demonstrate the pharmacokinetic importance of characterizing the expression and activity of TK1 and dCK during chemotherapy with thymidine and deoxycytidine analogs in order to optimize their efficacy.
Collapse
Affiliation(s)
- Ren Sun
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Staffan Eriksson
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Liya Wang
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
| |
Collapse
|
6
|
Lin S, Huang C, Sun J, Bollt O, Wang X, Martine E, Kang J, Taylor MD, Fang B, Singh PK, Koomen J, Hao J, Yang S. The mitochondrial deoxyguanosine kinase is required for cancer cell stemness in lung adenocarcinoma. EMBO Mol Med 2019; 11:e10849. [PMID: 31633874 PMCID: PMC6895611 DOI: 10.15252/emmm.201910849] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 09/17/2019] [Accepted: 09/20/2019] [Indexed: 12/14/2022] Open
Abstract
The mitochondrial deoxynucleotide triphosphate (dNTP) is maintained by the mitochondrial deoxynucleoside salvage pathway and dedicated for the mtDNA homeostasis, and the mitochondrial deoxyguanosine kinase (DGUOK) is a rate-limiting enzyme in this pathway. Here, we investigated the role of the DGUOK in the self-renewal of lung cancer stem-like cells (CSC). Our data support that DGUOK overexpression strongly correlates with cancer progression and patient survival. The depletion of DGUOK robustly inhibited lung adenocarcinoma tumor growth, metastasis, and CSC self-renewal. Mechanistically, DGUOK is required for the biogenesis of respiratory complex I and mitochondrial OXPHOS, which in turn regulates CSC self-renewal through AMPK-YAP1 signaling. The restoration of mitochondrial OXPHOS in DGUOK KO lung cancer cells using NDI1 was able to prevent AMPK-mediated phosphorylation of YAP and to rescue CSC stemness. Genetic targeting of DGUOK using doxycycline-inducible CRISPR/Cas9 was able to markedly induce tumor regression. Our findings reveal a novel role for mitochondrial dNTP metabolism in lung cancer tumor growth and progression, and implicate that the mitochondrial deoxynucleotide salvage pathway could be potentially targeted to prevent CSC-mediated therapy resistance and metastatic recurrence.
Collapse
Affiliation(s)
- Shengchen Lin
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Chongbiao Huang
- Key Laboratory of Cancer Prevention and Therapy, Department of Pancreatic Cancer, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin, China
| | - Jianwei Sun
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
- State Key Laboratory of Natural Resource Conservation and Utilization in Yunnan and Center for Life Science, School of Life Sciences, Yunnan University, Kunming, China
- South China Agricultural University, Guangzhou, China
| | - Oana Bollt
- Department of Surgery, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Xiuchao Wang
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
- Key Laboratory of Cancer Prevention and Therapy, Department of Pancreatic Cancer, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin, China
| | - Eric Martine
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Jiaxin Kang
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
- South China Agricultural University, Guangzhou, China
| | - Matthew D Taylor
- Department of Surgery, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Bin Fang
- Department of Molecular Oncology, Proteomics & Metabolomics Core, H. Lee Moffitt Cancer Center, Tampa, FL, USA
| | - Pankaj K Singh
- Department of Pathology and Microbiology, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - John Koomen
- Department of Molecular Oncology, Proteomics & Metabolomics Core, H. Lee Moffitt Cancer Center, Tampa, FL, USA
| | - Jihui Hao
- Key Laboratory of Cancer Prevention and Therapy, Department of Pancreatic Cancer, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin, China
| | - Shengyu Yang
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
- Department of Tumor Biology, H. Lee Moffitt Cancer Center, Tampa, FL, USA
| |
Collapse
|
7
|
Wang L, Zhang L, Sun R, Eriksson S. Negative Cooperative Binding of Thymidine, Ordered Substrate Binding, and Product Release of Human Mitochondrial Thymidine Kinase 2 Explain Its Complex Kinetic Properties and Physiological Functions. ACS OMEGA 2018; 3:8971-8979. [PMID: 31459030 PMCID: PMC6644362 DOI: 10.1021/acsomega.8b01376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 07/30/2018] [Indexed: 06/10/2023]
Abstract
Mitochondrial thymidine kinase 2 (TK2) catalyzes the phosphorylation of thymidine (dT) and deoxycytidine (dC) and is essential for mitochondrial function in post-mitotic tissues. The phosphorylation of dT shows negative cooperativity, but the phosphorylation of dC follows classical Michaelis-Menten kinetics. The enzyme is feedback-inhibited by its end products deoxythymidine triphosphate (dTTP) and deoxycytidine triphosphate (dCTP). In order to better understand the reaction mechanism and the negative cooperative behavior, we conducted isothermal titration calorimetry (ITC) and intrinsic tryptophan fluorescence (ITF) quenching studies with purified recombinant human TK2. Cooperative binding was observed with dT but not dC by the ITC analysis in accordance with earlier enzyme kinetic studies. The phosphate donor adenosine triphosphate (ATP) did not bind to either dTTP-bound or dTTP-free enzymes but bound tightly to the dT- or dC-TK2 complexes with large differences in enthalpy and entropy changes, strongly suggesting an ordered binding of the substrates and different conformational states of the ATP and dT- and dC-TK2 ternary complexes. dTTP binding was endothermic; however, dCTP could not be shown to interact with the enzyme. ITF quenching studies also revealed tight binding of dT, dC, deoxythymidine monophosphate, deoxycytidine monophosphate, and dTTP but not adenosine 5'-diphosphate or ATP. These results strongly indicate an ordered sequential binding of the substrates and ordered release of the products as well as different conformational states of the active site of TK2. These results help to explain the different kinetics observed with dT and dC as substrates, which have important implications for TK2 regulation in vivo.
Collapse
Affiliation(s)
- Liya Wang
- Department of Anatomy,
Physiology and Biochemistry, Swedish University
of Agricultural Sciences, Box 7011, SE-750 07 Uppsala, Sweden
| | - Li Zhang
- Department of Cell and Molecular Biology, Uppsala University, The Biomedical Centre, Box 590, SE-751 23 Uppsala, Sweden
| | - Ren Sun
- Department of Immunology, Genetics and
Pathology, Uppsala University, The Rudbeck
Laboratory, SE-751 85 Uppsala, Sweden
| | - Staffan Eriksson
- Department of Anatomy,
Physiology and Biochemistry, Swedish University
of Agricultural Sciences, Box 7011, SE-750 07 Uppsala, Sweden
| |
Collapse
|
8
|
Rahman MF, Raj R, Govindarajan R. Identification of Structural and Molecular Features Involved in the Transport of 3'-Deoxy-Nucleoside Analogs by Human Equilibrative Nucleoside Transporter 3. Drug Metab Dispos 2018. [PMID: 29530865 PMCID: PMC5896370 DOI: 10.1124/dmd.117.079400] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Combination antiretroviral drug treatments depend on 3′-deoxy-nucleoside analogs such as 3′-azido-3′-deoxythymidine (AZT) and 2′3′-dideoxyinosine (DDI). Despite being effective in inhibiting human immunodeficiency virus replication, these drugs produce a range of toxicities, including myopathy, pancreatitis, neuropathy, and lactic acidosis, that are generally considered as sequelae to mitochondrial damage. Although cell surface–localized nucleoside transporters, such as human equilibrative nucleoside transporter 2 (hENT2) and human concentrative nucleoside transporter 1 (hCNT1), are known to increase the carrier-mediated uptake of 3′-deoxy-nucleoside analogs into cells, another ubiquitously expressed intracellular nucleoside transporter (namely, hENT3) has been implicated in the mitochondrial transport of 3′-deoxy-nucleoside analogs. Using site-directed mutagenesis, generation of chimeric hENTs, and 3H-permeant flux measurements in mutant/chimeric RNA–injected Xenopus oocytes, here we identified the molecular determinants of hENT3 that dictate membrane translocation of 3′-deoxy-nucleoside analogs. Our findings demonstrated that whereas hENT1 had no significant transport activity toward 3′-deoxy-nucleoside analogs, hENT3 was capable of transporting 3′-deoxy-nucleoside analogs similar to hENT2. Transport analyses of hENT3-hENT1 chimeric constructs demonstrated that the N-terminal half of hENT3 is primarily responsible for the hENT3–3′-deoxy-nucleoside analog interaction. In addition, mutagenic studies identified that 225D and 231L in the N-terminal half of hENT3 partially contribute to the ability of hENT3 to transport AZT and DDI. The identification of the transporter segment and amino acid residues that are important in hENT3 transport of 3′-deoxy-nucleoside analogs may present a possible mechanism for overcoming the adverse toxicities associated with 3′-deoxy-nucleoside analog treatment and may guide rational development of novel nucleoside analogs.
Collapse
Affiliation(s)
- Md Fazlur Rahman
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy (M.F.R., R.R., R.G.) and Translational Therapeutics, Ohio State University Comprehensive Cancer Center (R.G.), The Ohio State University, Columbus, Ohio
| | - Radhika Raj
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy (M.F.R., R.R., R.G.) and Translational Therapeutics, Ohio State University Comprehensive Cancer Center (R.G.), The Ohio State University, Columbus, Ohio
| | - Rajgopal Govindarajan
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy (M.F.R., R.R., R.G.) and Translational Therapeutics, Ohio State University Comprehensive Cancer Center (R.G.), The Ohio State University, Columbus, Ohio
| |
Collapse
|
9
|
Wang L. Mitochondrial purine and pyrimidine metabolism and beyond. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2017; 35:578-594. [PMID: 27906631 DOI: 10.1080/15257770.2015.1125001] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Carefully balanced deoxynucleoside triphosphate (dNTP) pools are essential for both nuclear and mitochondrial genome replication and repair. Two synthetic pathways operate in cells to produce dNTPs, e.g., the de novo and the salvage pathways. The key regulatory enzymes for de novo synthesis are ribonucleotide reductase (RNR) and thymidylate synthase (TS), and this process is considered to be cytosolic. The salvage pathway operates both in the cytosol (TK1 and dCK) and the mitochondria (TK2 and dGK). Mitochondrial dNTP pools are separated from the cytosolic ones owing to the double membrane structure of the mitochondria, and are formed by the salvage enzymes TK2 and dGK together with NMPKs and NDPK in postmitotic tissues, while in proliferating cells the mitochondrial dNTPs are mainly imported from the cytosol produced by the cytosolic pathways. Imbalanced mitochondrial dNTP pools lead to mtDNA depletion and/or deletions resulting in serious mitochondrial diseases. The mtDNA depletion syndrome is caused by deficiencies not only in enzymes in dNTP synthesis (TK2, dGK, p53R2, and TP) and mtDNA replication (mtDNA polymerase and twinkle helicase), but also in enzymes in other metabolic pathways such as SUCLA2 and SUCLG1, ABAT and MPV17. Basic questions are why defects in these enzymes affect dNTP synthesis and how important is mitochondrial nucleotide synthesis in the whole cell/organism perspective? This review will focus on recent studies on purine and pyrimidine metabolism, which have revealed several important links that connect mitochondrial nucleotide metabolism with amino acids, glucose, and fatty acid metabolism.
Collapse
Affiliation(s)
- Liya Wang
- a Department of Anatomy, Physiology and Biochemistry , Swedish University of Agricultural Sciences , Uppsala , Sweden
| |
Collapse
|
10
|
Abstract
Telbivudine (LdT) is an antiviral agent currently used in the treatment of chronic hepatitis B virus, which was first approved by the US FDA in 2006. The safety of LdT is of great importance for patients that receive long-term treatment for this condition. It has been confirmed that patients treated with LdT have significantly elevated creatine kinase levels. However, the mechanism responsible for this adverse reaction is unclear. This review summarizes the current literature of the adverse reactions of LdT and the possible mechanisms that are involved in chronic hepatitis B infection. Thus, we aim to provide guidance on best practices in using LdT and to provide evidence of the possible mechanisms of LdT-associated adverse reactions.
Collapse
Affiliation(s)
- Jianfei Long
- Department of Pharmacy, HuaShan Hospital, Fudan University, No. 12 Middle Wu Lu Mu Qi Road, Shanghai 200040, China
| | - Min Wang
- College of Pharmacy, Fudan University, Shanghai, China
| | - Bicui Chen
- Department of Pharmacy, HuaShan Hospital, Fudan University, No. 12 Middle Wu Lu Mu Qi Road, Shanghai 200040, China
| | - Jiming Zhang
- Department of Infectious Diseases, HuaShan Hospital, Fudan University, No.12 Middle Wu Lu Mu Qi Road, Shanghai 200040, China
| | - Bin Wang
- Department of Pharmacy, HuaShan Hospital, Fudan University, No. 12 Middle Wu Lu Mu Qi Road, Shanghai 200040, China
| |
Collapse
|
11
|
Sanchez AB, Kaul M. Neuronal Stress and Injury Caused by HIV-1, cART and Drug Abuse: Converging Contributions to HAND. Brain Sci 2017; 7:brainsci7030025. [PMID: 28241493 PMCID: PMC5366824 DOI: 10.3390/brainsci7030025] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 02/15/2017] [Accepted: 02/20/2017] [Indexed: 12/21/2022] Open
Abstract
Multiple mechanisms appear to contribute to neuronal stress and injury underlying HIV-associated neurocognitive disorders (HAND), which occur despite the successful introduction of combination antiretroviral therapy (cART). Evidence is accumulating that components of cART can itself be neurotoxic upon long-term exposure. In addition, abuse of psychostimulants, such as methamphetamine (METH), seems to compromise antiretroviral therapy and aggravate HAND. However, the combined effect of virus and recreational and therapeutic drugs on the brain is still incompletely understood. However, several lines of evidence suggest a shared critical role of oxidative stress, compromised neuronal energy homeostasis and autophagy in promotion and prevention of neuronal dysfunction associated with HIV-1 infection, cART and psychostimulant use. In this review, we present a synopsis of recent work related to neuronal stress and injury induced by HIV infection, antiretrovirals (ARVs) and the highly addictive psychostimulant METH.
Collapse
Affiliation(s)
- Ana B Sanchez
- Immunity and Pathogenesis Program, Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA.
| | - Marcus Kaul
- Immunity and Pathogenesis Program, Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA.
- Department of Psychiatry, University of California San Diego, San Diego, CA 92093, USA.
| |
Collapse
|
12
|
Vilarinho S, Sari S, Yilmaz G, Stiegler AL, Boggon TJ, Jain D, Akyol G, Dalgic B, Günel M, Lifton RP. Recurrent recessive mutation in deoxyguanosine kinase causes idiopathic noncirrhotic portal hypertension. Hepatology 2016; 63:1977-86. [PMID: 26874653 PMCID: PMC4874872 DOI: 10.1002/hep.28499] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Accepted: 02/10/2016] [Indexed: 12/30/2022]
Abstract
UNLABELLED Despite advances in the diagnosis and management of idiopathic noncirrhotic portal hypertension, its pathogenesis remains elusive. Insight may be gained from study of early-onset familial idiopathic noncirrhotic portal hypertension, in which Mendelian mutations may account for disease. We performed exome sequencing of eight subjects from six kindreds with onset of portal hypertension of indeterminate etiology during infancy or childhood. Three subjects from two consanguineous families shared the identical rare homozygous p.N46S mutation in DGUOK, a deoxyguanosine kinase required for mitochondrial DNA replication; haplotype sharing demonstrated that the mutation in the two families was inherited from a remote common ancestor. All three affected subjects had stable portal hypertension with noncirrhotic liver disease for 6-16 years of follow-up. This mutation impairs adenosine triphosphate binding and reduces catalytic activity. Loss-of-function mutations in DGUOK have previously been implicated in cirrhosis and liver failure but not in isolated portal hypertension. Interestingly, treatment of patients with human immunodeficiency viral infection with the nucleoside analogue didanosine is known to cause portal hypertension in a subset of patients and lowers deoxyguanosine kinase levels in vitro; the current findings implicate these effects on deoxyguanosine kinase in the causal mechanism. CONCLUSION Our findings provide new insight into the mechanisms mediating inherited and acquired noncirrhotic portal hypertension, expand the phenotypic spectrum of DGUOK deficiency, and provide a new genetic test for a specific cause of idiopathic noncirrhotic portal hypertension. (Hepatology 2016;63:1977-1986).
Collapse
Affiliation(s)
- Sílvia Vilarinho
- Department of Internal Medicine, Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut, USA,Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA,Correspondence should be addressed to: Richard P. Lifton, M.D., Ph.D., Departments of Genetics and Internal Medicine, Howard Hughes Medical Institute, Yale University School of Medicine, 333 Cedar St., SHM I308, New Haven, CT 06510, USA. Telephone: +1-203-737-4420, Fax: +1-203-785-7560, ; or Sílvia Vilarinho, M.D., Ph.D., Departments of Genetics and Internal Medicine, Section of Digestive Diseases, Yale University School of Medicine, 333 Cedar St., LMP1080, New Haven, CT 06510, USA. Telephone: +1-203-737-1833, Fax: +1-203-737-1755,
| | - Sinan Sari
- Department of Pediatrics, Division of Gastroenterology, Gazi University, Faculty of Medicine, Ankara, Turkey
| | - Güldal Yilmaz
- Department of Pathology, Gazi University, Faculty of Medicine, Ankara, Turkey
| | - Amy L. Stiegler
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Titus J. Boggon
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Dhanpat Jain
- Department of Internal Medicine, Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut, USA,Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA,Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Gulen Akyol
- Department of Pathology, Gazi University, Faculty of Medicine, Ankara, Turkey
| | - Buket Dalgic
- Department of Pediatrics, Division of Gastroenterology, Gazi University, Faculty of Medicine, Ankara, Turkey
| | - Murat Günel
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA,Department of Neurosurgery, Yale Program in Brain Tumor Research, Yale University School of Medicine, New Haven, Connecticut, USA,Yale Center for Mendelian Genomics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Richard P. Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA,Department of Neurosurgery, Yale Program in Brain Tumor Research, Yale University School of Medicine, New Haven, Connecticut, USA,Department of Internal Medicine and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA,Correspondence should be addressed to: Richard P. Lifton, M.D., Ph.D., Departments of Genetics and Internal Medicine, Howard Hughes Medical Institute, Yale University School of Medicine, 333 Cedar St., SHM I308, New Haven, CT 06510, USA. Telephone: +1-203-737-4420, Fax: +1-203-785-7560, ; or Sílvia Vilarinho, M.D., Ph.D., Departments of Genetics and Internal Medicine, Section of Digestive Diseases, Yale University School of Medicine, 333 Cedar St., LMP1080, New Haven, CT 06510, USA. Telephone: +1-203-737-1833, Fax: +1-203-737-1755,
| |
Collapse
|
13
|
Antiretrovirals, Methamphetamine, and HIV-1 Envelope Protein gp120 Compromise Neuronal Energy Homeostasis in Association with Various Degrees of Synaptic and Neuritic Damage. Antimicrob Agents Chemother 2015; 60:168-79. [PMID: 26482305 DOI: 10.1128/aac.01632-15] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 10/12/2015] [Indexed: 01/06/2023] Open
Abstract
HIV-1 infection frequently causes HIV-associated neurocognitive disorders (HAND) despite combination antiretroviral therapy (cART). Evidence is accumulating that components of cART can themselves be neurotoxic upon long-term exposure. In addition, abuse of psychostimulants, such as methamphetamine, seems to aggravate HAND and compromise antiretroviral therapy. However, the combined effect of virus and recreational and therapeutic drugs on the brain is poorly understood. Therefore, we exposed mixed neuronal-glial cerebrocortical cells to antiretrovirals (ARVs) (zidovudine [AZT], nevirapine [NVP], saquinavir [SQV], and 118-D-24) of four different pharmacological categories and to methamphetamine and, in some experiments, the HIV-1 gp120 protein for 24 h and 7 days. Subsequently, we assessed neuronal injury by fluorescence microscopy, using specific markers for neuronal dendrites and presynaptic terminals. We also analyzed the disturbance of neuronal ATP levels and assessed the involvement of autophagy by using immunofluorescence and Western blotting. ARVs caused alterations of neurites and presynaptic terminals primarily during the 7-day incubation and depending on the specific compounds and their combinations with and without methamphetamine. Similarly, the loss of neuronal ATP was context specific for each of the drugs or combinations thereof, with and without methamphetamine or viral gp120. Loss of ATP was associated with activation of AMP-activated protein kinase (AMPK) and autophagy, which, however, failed to restore normal levels of neuronal ATP. In contrast, boosting autophagy with rapamycin prevented the long-term drop of ATP during exposure to cART in combination with methamphetamine or gp120. Our findings indicate that the overall positive effect of cART on HIV infection is accompanied by detectable neurotoxicity, which in turn may be aggravated by methamphetamine.
Collapse
|
14
|
Zidovudine induces downregulation of mitochondrial deoxynucleoside kinases: implications for mitochondrial toxicity of antiviral nucleoside analogs. Antimicrob Agents Chemother 2014; 58:6758-66. [PMID: 25182642 DOI: 10.1128/aac.03613-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Mitochondrial thymidine kinase 2 (TK2) and deoxyguanosine kinase (dGK) catalyze the initial phosphorylation of deoxynucleosides in the synthesis of the DNA precursors required for mitochondrial DNA (mtDNA) replication and are essential for mitochondrial function. Antiviral nucleosides are known to cause toxic mitochondrial side effects. Here, we examined the effects of 3'-azido-2',3'-dideoxythymidine (AZT) (zidovudine) on mitochondrial TK2 and dGK levels and found that AZT treatment led to downregulation of mitochondrial TK2 and dGK in U2OS cells, whereas cytosolic deoxycytidine kinase (dCK) and thymidine kinase 1 (TK1) levels were not affected. The AZT effects on mitochondrial TK2 and dGK were similar to those of oxidants (e.g., hydrogen peroxide); therefore, we examined the oxidative effects of AZT. We found a modest increase in cellular reactive oxygen species (ROS) levels in the AZT-treated cells. The addition of uridine to AZT-treated cells reduced ROS levels and protein oxidation and prevented the degradation of mitochondrial TK2 and dGK. In organello studies indicated that the degradation of mitochondrial TK2 and dGK is a mitochondrial event. These results suggest that downregulation of mitochondrial TK2 and dGK may lead to decreased mitochondrial DNA precursor pools and eventually mtDNA depletion, which has significant implications for the regulation of mitochondrial nucleotide biosynthesis and for antiviral therapy using nucleoside analogs.
Collapse
|