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Patronas EM, Balber T, Miller A, Geist BK, Michligk A, Vraka C, Krisch M, Rohr-Udilova N, Haschemi A, Viernstein H, Hacker M, Mitterhauser M. A fingerprint of 2-[ 18F]FDG radiometabolites - How tissue-specific metabolism beyond 2-[ 18F]FDG-6-P could affect tracer accumulation. iScience 2023; 26:108137. [PMID: 37867937 PMCID: PMC10585399 DOI: 10.1016/j.isci.2023.108137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/01/2023] [Accepted: 10/02/2023] [Indexed: 10/24/2023] Open
Abstract
Studies indicate that the radiotracer 2-[18F]fluoro-2-deoxy-D-glucose (2-[18F]FDG) can be metabolized beyond 2-[18F]FDG-6-phosphate (2-[18F]FDG-6-P), but its metabolism is incompletely understood. Most importantly, it remains unclear whether downstream metabolism affects tracer accumulation in vivo. Here we present a fingerprint of 2-[18F]FDG radiometabolites over time in cancer cells, corresponding tumor xenografts and murine organs. Strikingly, radiometabolites representing glycogen metabolism or the oxPPP correlated inversely with tracer accumulation across all examined tissues. Recent studies suggest that not only hexokinase, but also hexose-6-phosphate dehydrogenase (H6PD), an enzyme of the oxidative pentose phosphate pathway (oxPPP), determines 2-[18F]FDG accumulation. However, little is known about the corresponding enzyme glucose-6-phosphate dehydrogenase (G6PD). Our mechanistic in vitro experiments on the role of the oxPPP propose that 2-[18F]FDG can be metabolized via both G6PD and H6PD, but data from separate enzyme knockdown suggest diverging roles in downstream tracer metabolism. Overall, we propose that tissue-specific metabolism beyond 2-[18F]FDG-6-P could matter for imaging.
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Affiliation(s)
- Eva-Maria Patronas
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna 1090, Austria
- Division of Pharmaceutical Technology and Biopharmaceutics, Department of Pharmaceutical Sciences, University of Vienna, Vienna 1090, Austria
| | - Theresa Balber
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna 1090, Austria
- Ludwig Boltzmann Institute Applied Diagnostics, Vienna 1090, Austria
| | - Anne Miller
- Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna 1090, Austria
| | - Barbara Katharina Geist
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna 1090, Austria
| | - Antje Michligk
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna 1090, Austria
| | - Chrysoula Vraka
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna 1090, Austria
| | - Maximilian Krisch
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna 1090, Austria
| | - Nataliya Rohr-Udilova
- Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna 1090, Austria
| | - Arvand Haschemi
- Department of Laboratory Medicine, Medical University of Vienna, Vienna 1090, Austria
| | - Helmut Viernstein
- Division of Pharmaceutical Technology and Biopharmaceutics, Department of Pharmaceutical Sciences, University of Vienna, Vienna 1090, Austria
| | - Marcus Hacker
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna 1090, Austria
| | - Markus Mitterhauser
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna 1090, Austria
- Ludwig Boltzmann Institute Applied Diagnostics, Vienna 1090, Austria
- University of Vienna, Faculty of Chemistry, Institute of Inorganic Chemistry, Vienna 1090, Austria
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Abhishek S, Deeksha W, Nethravathi KR, Davari MD, Rajakumara E. Allosteric crosstalk in modular proteins: Function fine-tuning and drug design. Comput Struct Biotechnol J 2023; 21:5003-5015. [PMID: 37867971 PMCID: PMC10589753 DOI: 10.1016/j.csbj.2023.10.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/07/2023] [Accepted: 10/08/2023] [Indexed: 10/24/2023] Open
Abstract
Modular proteins are regulatory proteins that carry out more than one function. These proteins upregulate or downregulate a biochemical cascade to establish homeostasis in cells. To switch the function or alter the efficiency (based on cellular needs), these proteins require different facilitators that bind to a site different from the catalytic (active/orthosteric) site, aka 'allosteric site', and fine-tune their function. These facilitators (or effectors) are allosteric modulators. In this Review, we have discussed the allostery, characterized them based on their mechanisms, and discussed how allostery plays an important role in the activity modulation and function fine-tuning of proteins. Recently there is an emergence in the discovery of allosteric drugs. We have also emphasized the role, significance, and future of allostery in therapeutic applications.
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Affiliation(s)
- Suman Abhishek
- Macromolecular Structural Biology lab, Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana 502284, India
| | - Waghela Deeksha
- Macromolecular Structural Biology lab, Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana 502284, India
| | | | - Mehdi D. Davari
- Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Halle 06120, Germany
| | - Eerappa Rajakumara
- Macromolecular Structural Biology lab, Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana 502284, India
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Batsios G, Taglang C, Gillespie AM, Viswanath P. Imaging telomerase reverse transcriptase expression in oligodendrogliomas using hyperpolarized δ-[1- 13C]-gluconolactone. Neurooncol Adv 2023; 5:vdad092. [PMID: 37600229 PMCID: PMC10433788 DOI: 10.1093/noajnl/vdad092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/22/2023] Open
Abstract
Background Telomere maintenance by telomerase reverse transcriptase (TERT) is essential for immortality in most cancers, including oligodendrogliomas. Agents that disrupt telomere maintenance such as the telomere uncapping agent 6-thio-2'-deoxyguanosine (6-thio-dG) are in clinical trials. We previously showed that TERT expression in oligodendrogliomas is associated with upregulation of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the pentose phosphate pathway (PPP). We also showed that hyperpolarized δ-[1-13C]-gluconolactone metabolism to 6-phosphogluconate (6-PG) can be used to probe the PPP in glioblastomas. The goal of this study was to determine whether hyperpolarized 13C imaging using δ-[1-13C]-gluconolactone can monitor TERT expression and response to 6-thio-dG in oligodendrogliomas. Methods We examined patient-derived oligodendroglioma cells and orthotopic tumors to assess the link between TERT and hyperpolarized δ-[1-13C]-gluconolactone metabolism. We performed in vivo imaging to assess the ability of hyperpolarized δ-[1-13C]-gluconolactone to report on TERT and response to 6-thio-dG in rats bearing orthotopic oligodendrogliomas in vivo. Results Doxycycline-inducible TERT silencing abrogated 6-PG production from hyperpolarized δ-[1-13C]-gluconolactone in oligodendroglioma cells, consistent with the loss of G6PD activity. Rescuing TERT expression by doxycycline removal restored G6PD activity and, concomitantly, 6-PG production. 6-PG production from hyperpolarized δ-[1-13C]-gluconolactone demarcated TERT-expressing tumor from surrounding TERT-negative normal brain in vivo. Importantly, 6-thio-dG abrogated 6-PG production at an early timepoint preceding MRI-detectable alterations in rats bearing orthotopic oligodendrogliomas in vivo. Conclusions These results indicate that hyperpolarized δ-[1-13C]-gluconolactone reports on TERT expression and early response to therapy in oligodendrogliomas. Our studies identify a novel agent for imaging tumor proliferation and treatment response in oligodendroglioma patients.
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Affiliation(s)
- Georgios Batsios
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Celine Taglang
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Anne Marie Gillespie
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Pavithra Viswanath
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
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Ran Y, He J, Peng W, Liu Z, Mei Y, Zhou Y, Yin N, Qi H. Development and validation of a transcriptomic signature-based model as the predictive, preventive, and personalized medical strategy for preterm birth within 7 days in threatened preterm labor women. EPMA J 2022; 13:87-106. [PMID: 35273661 PMCID: PMC8897543 DOI: 10.1007/s13167-021-00268-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 12/24/2021] [Indexed: 12/08/2022]
Abstract
Preterm birth (PTB) is the leading cause of neonatal death. The essential strategy to prevent PTB is the accurate identification of threatened preterm labor (TPTL) women who will have PTB in a short time (< 7 days). Here, we aim to propose a clinical model to contribute to the effective prediction, precise prevention, and personalized medical treatment for PTB < 7 days in TPTL women through bioinformatics analysis and prospective cohort studies. In this study, the 1090 key genes involved in PTB < 7 days in the peripheral blood of TPTL women were ascertained using WGCNA. Based on this, the biological basis of immune-inflammatory activation (e.g., IFNγ and TNFα signaling) as well as immune cell disorders (e.g., monocytes and Th17 cells) in PTB < 7 days were revealed. Then, four core genes (JOSD1, IDNK, ZMYM3, and IL1B) that best represent their transcriptomic characteristics were screened by SVM and LASSO algorithm. Therefore, a prediction model with an AUC of 0.907 was constructed, which was validated in a larger population (AUC = 0.783). Moreover, the predictive value (AUC = 0.957) and clinical feasibility of this model were verified through the clinical prospective cohort we established. In conclusion, in the context of Predictive, Preventive, and Personalized Medicine (3PM), we have developed and validated a model to predict PTB < 7 days in TPTL women. This is promising to greatly improve the accuracy of clinical prediction, which would facilitate the personalized management of TPTL women to precisely prevent PTB < 7 days and improve maternal-fetal outcomes.
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Affiliation(s)
- Yuxin Ran
- Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, No.1 Youyi Rd, Yuzhong District, Chongqing, 400016 China
- Chongqing Health Center for Women and Children, No. 120 Longshan Road, Yubei District, Chongqing, 401120 China
- Chongqing Key Laboratory of Maternal and Fetal Medicine, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
- Joint International Research Laboratory of Reproduction and Development of Chinese Ministry of Education, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
| | - Jie He
- Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, No.1 Youyi Rd, Yuzhong District, Chongqing, 400016 China
- Chongqing Key Laboratory of Maternal and Fetal Medicine, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
- Joint International Research Laboratory of Reproduction and Development of Chinese Ministry of Education, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
| | - Wei Peng
- Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, No.1 Youyi Rd, Yuzhong District, Chongqing, 400016 China
- Chongqing Key Laboratory of Maternal and Fetal Medicine, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
- Joint International Research Laboratory of Reproduction and Development of Chinese Ministry of Education, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
| | - Zheng Liu
- Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, No.1 Youyi Rd, Yuzhong District, Chongqing, 400016 China
- Chongqing Key Laboratory of Maternal and Fetal Medicine, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
- Joint International Research Laboratory of Reproduction and Development of Chinese Ministry of Education, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
| | - Youwen Mei
- Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, No.1 Youyi Rd, Yuzhong District, Chongqing, 400016 China
- Chongqing Key Laboratory of Maternal and Fetal Medicine, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
- Joint International Research Laboratory of Reproduction and Development of Chinese Ministry of Education, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
| | - Yunqian Zhou
- Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, No.1 Youyi Rd, Yuzhong District, Chongqing, 400016 China
- Chongqing Key Laboratory of Maternal and Fetal Medicine, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
- Joint International Research Laboratory of Reproduction and Development of Chinese Ministry of Education, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
| | - Nanlin Yin
- Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, No.1 Youyi Rd, Yuzhong District, Chongqing, 400016 China
- Chongqing Key Laboratory of Maternal and Fetal Medicine, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
- Joint International Research Laboratory of Reproduction and Development of Chinese Ministry of Education, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
- Center for Reproductive Medicine, The First Affiliated Hospital of Chongqing Medical University, No.1 Youyi Rd, Yuzhong District, Chongqing, 400016 China
| | - Hongbo Qi
- Chongqing Health Center for Women and Children, No. 120 Longshan Road, Yubei District, Chongqing, 401120 China
- Chongqing Key Laboratory of Maternal and Fetal Medicine, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
- Joint International Research Laboratory of Reproduction and Development of Chinese Ministry of Education, Chongqing Medical University, No. 1 Yixueyuan Rd, Yuzhong District, Chongqing, 400016 China
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Machuca A, Garcia-Calvo E, Anunciação DS, Luque-Garcia JL. Integration of Transcriptomics and Metabolomics to Reveal the Molecular Mechanisms Underlying Rhodium Nanoparticles-Based Photodynamic Cancer Therapy. Pharmaceutics 2021; 13:pharmaceutics13101629. [PMID: 34683922 PMCID: PMC8539937 DOI: 10.3390/pharmaceutics13101629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/24/2021] [Accepted: 10/04/2021] [Indexed: 12/12/2022] Open
Abstract
Rhodium nanoparticles have recently been described as promising photosensitizers due to their low toxicity in the absence of near-infrared irradiation, but their high cytotoxicity when irradiated. Irradiation is usually carried out with a laser source, which allows the treatment to be localized in a specific area, thus avoiding undesirable side effects on healthy tissues. In this study, a multi-omics approach based on the combination of microarray-based transcriptomics and mass spectrometry-based untargeted and targeted metabolomics has provided a global picture of the molecular mechanisms underlying the anti-tumoral effect of rhodium nanoparticle-based photodynamic therapy. The results have shown the ability of these nanoparticles to promote apoptosis by suppressing or promoting anti- and pro-apoptotic factors, respectively, and by affecting the energy machinery of tumor cells, mainly blocking the β-oxidation, which is reflected in the accumulation of free fatty acids and in the decrease in ATP, ADP and NAD+ levels.
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Affiliation(s)
- Andres Machuca
- Department Analytical Chemistry, Faculty of Chemical Sciences, Complutense University of Madrid, 28040 Madrid, Spain; (A.M.); (E.G.-C.)
| | - Estefania Garcia-Calvo
- Department Analytical Chemistry, Faculty of Chemical Sciences, Complutense University of Madrid, 28040 Madrid, Spain; (A.M.); (E.G.-C.)
| | - Daniela S. Anunciação
- Institute of Chemistry and Biotechnology, Federal University of Alagoas, Campus A. C. Simões, 57072-900 Maceió, Brazil;
| | - Jose L. Luque-Garcia
- Department Analytical Chemistry, Faculty of Chemical Sciences, Complutense University of Madrid, 28040 Madrid, Spain; (A.M.); (E.G.-C.)
- Correspondence: ; Tel.: +34-913-944-212
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Wang Y, Mittermaier AK. Characterizing Bi-substrate Enzyme Kinetics at High Resolution by 2D-ITC. Anal Chem 2021; 93:12723-12732. [PMID: 34514786 DOI: 10.1021/acs.analchem.1c02705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
There is growing interest in using isothermal titration calorimetry (ITC) to characterize enzyme kinetics by measuring the heat produced or absorbed by catalysis in real time. Since virtually all chemical reactions are associated with changes in enthalpy, ITC represents a robust and nearly universal experimental approach. Nevertheless, there are technical challenges that limit ITC's applicability. For instance, the full kinetic characterization of enzymes with two substrates (bi-substrate enzymes), which comprise the majority of known examples, requires a series of experiments to be performed as the concentrations of both substrates are varied. This is a time-consuming and expensive process using current ITC methods since many (>5) individual experiments must be performed independently to obtain a sufficient quantity of data. We have developed a new ITC method, which we term 2D-ITC, which maps the reaction velocity as a function of two substrate concentrations in a single, roughly 2 h long experiment. This method provides a level of detail that rivals or exceeds any existing enzyme assay, as a single experiment generates on the order of 7000 catalytic rate measurements. In a proof-of-principle application to rabbit muscle pyruvate kinase (rMPK), the method correctly identified the enzyme's random sequential mechanism and allosteric catalytic suppression by the amino acid phenylalanine (Phe). Unexpectedly, we found that while Phe reduces affinity for the substrate phosphoenolpyruvate, a known phenomenon, it also alleviates inhibition by the reaction product ATP, which had not been reported previously. Given the relative abundance of ATP in the cell, this opposing effect is expected to have a substantial impact on rMPK activity.
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Affiliation(s)
- Yun Wang
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | - Anthony K Mittermaier
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
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Batsios G, Taglang C, Cao P, Gillespie AM, Najac C, Subramani E, Wilson DM, Flavell RR, Larson PEZ, Ronen SM, Viswanath P. Imaging 6-Phosphogluconolactonase Activity in Brain Tumors In Vivo Using Hyperpolarized δ-[1- 13C]gluconolactone. Front Oncol 2021; 11:589570. [PMID: 33937017 PMCID: PMC8082394 DOI: 10.3389/fonc.2021.589570] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 03/23/2021] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION The pentose phosphate pathway (PPP) is essential for NADPH generation and redox homeostasis in cancer, including glioblastomas. However, the precise contribution to redox and tumor proliferation of the second PPP enzyme 6-phosphogluconolactonase (PGLS), which converts 6-phospho-δ-gluconolactone to 6-phosphogluconate (6PG), remains unclear. Furthermore, non-invasive methods of assessing PGLS activity are lacking. The goal of this study was to examine the role of PGLS in glioblastomas and assess the utility of probing PGLS activity using hyperpolarized δ-[1-13C]gluconolactone for non-invasive imaging. METHODS To interrogate the function of PGLS in redox, PGLS expression was silenced in U87, U251 and GS2 glioblastoma cells by RNA interference and levels of NADPH and reduced glutathione (GSH) measured. Clonogenicity assays were used to assess the effect of PGLS silencing on glioblastoma proliferation. Hyperpolarized δ-[1-13C]gluconolactone metabolism to 6PG was assessed in live cells treated with the chemotherapeutic agent temozolomide (TMZ) or with vehicle control. 13C 2D echo-planar spectroscopic imaging (EPSI) studies of hyperpolarized δ-[1-13C]gluconolactone metabolism were performed on rats bearing orthotopic glioblastoma tumors or tumor-free controls on a 3T spectrometer. Longitudinal 2D EPSI studies of hyperpolarized δ-[1-13C]gluconolactone metabolism and T2-weighted magnetic resonance imaging (MRI) were performed in rats bearing orthotopic U251 tumors following treatment with TMZ to examine the ability of hyperpolarized δ-[1-13C]gluconolactone to report on treatment response. RESULTS PGLS knockdown downregulated NADPH and GSH, elevated oxidative stress and inhibited clonogenicity in all models. Conversely, PGLS expression and activity and steady-state NADPH and GSH were higher in tumor tissues from rats bearing orthotopic glioblastoma xenografts relative to contralateral brain and tumor-free brain. Importantly, [1-13C]6PG production from hyperpolarized δ-[1-13C]gluconolactone was observed in live glioblastoma cells and was significantly reduced by treatment with TMZ. Furthermore, hyperpolarized δ-[1-13C]gluconolactone metabolism to [1-13C]6PG could differentiate tumor from contralateral normal brain in vivo. Notably, TMZ significantly reduced 6PG production from hyperpolarized δ-[1-13C]gluconolactone at an early timepoint prior to volumetric alterations as assessed by anatomical imaging. CONCLUSIONS Collectively, we have, for the first time, identified a role for PGLS activity in glioblastoma proliferation and validated the utility of probing PGLS activity using hyperpolarized δ-[1-13C]gluconolactone for non-invasive in vivo imaging of glioblastomas and their response to therapy.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Sabrina M. Ronen
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States
| | - Pavithra Viswanath
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States
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Wang Y, Wang G, Moitessier N, Mittermaier AK. Enzyme Kinetics by Isothermal Titration Calorimetry: Allostery, Inhibition, and Dynamics. Front Mol Biosci 2020; 7:583826. [PMID: 33195429 PMCID: PMC7604385 DOI: 10.3389/fmolb.2020.583826] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/11/2020] [Indexed: 12/14/2022] Open
Abstract
Isothermal titration calorimetry (ITC) involves accurately measuring the heat that is released or absorbed in real time when one solution is titrated into another. This technique is usually used to measure the thermodynamics of binding reactions. However, there is mounting interest in using it to measure reaction kinetics, particularly enzymatic catalysis. This application of ITC has been steadily growing for the past two decades, and the method is proving to be sensitive, generally applicable, and capable of providing information on enzyme activity that is difficult to obtain using traditional biochemical assays. This review aims to give a broad overview of the use of ITC to measure enzyme kinetics. It describes several different classes of ITC experiment, their strengths and weaknesses, and recent methodological advancements. A summary of applications in the literature is given and several examples where ITC has been used to investigate challenging aspects of enzyme behavior are presented in more detail. These include examples of allostery, where small-molecule binding outside the active site modulates activity. We describe the use of ITC to measure the strength, mode (i.e., competitive, uncompetitive, or mixed), and association and dissociation kinetics of enzyme inhibitors. Further, we provide examples of ITC applied to complex, heterogeneous mixtures, such as insoluble substrates and live cells. These studies exemplify the wide range of problems where ITC can provide answers, and illustrate the versatility of the technique and potential for future development and applications.
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Affiliation(s)
- Yun Wang
- Department of Chemistry, McGill University, Montreal, QC, Canada
| | - Guanyu Wang
- Department of Chemistry, McGill University, Montreal, QC, Canada
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Wu XM, Jin C, Gu YL, Chen WQ, Zhu MQ, Zhang S, Zhang Z. Gluconokinase IDNK Promotes Cell Proliferation and Inhibits Apoptosis in Hepatocellular Carcinoma. Onco Targets Ther 2020; 13:1767-1776. [PMID: 32161472 PMCID: PMC7049873 DOI: 10.2147/ott.s234055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 02/13/2020] [Indexed: 01/20/2023] Open
Abstract
Purpose Hepatocellular carcinoma (HCC) is one of the deadliest cancers globally with a poor prognosis. Breakthroughs in the treatment of HCC are urgently needed. This study explored the role of IDNK in the development and progression of HCC. Methods IDNK expression was suppressed using short hairpin (shRNA) in BEL-7404 and Huh-7 cells. The expression of IDNK in HCC cells after IDNK knockdown was evaluated by real-time quantitative RT-PCR analysis and Western blot. After IDNK silencing, the proliferation and apoptosis of HCC cells were evaluated by Celigo cell counting, flow cytometry analysis, MTT assay, and caspase3/7 assay. Gene expressions in BEL-7404 cells transfected with IDNK shRNA lentivirus plasmid and blank control plasmid were evaluated by microarray analysis. The differentially expressed genes induced by deregulation of IDNKwere identified, followed by pathway analysis. Results The expression of IDNK at the mRNA and protein levels was considerably reduced in shRNA IDNK transfected cells. Knockdown of IDNK significantly inhibited HCC cell proliferation and increased cell apoptosis. A total of 1196 genes (585 upregulated and 611 downregulated) were differentially expressed in IDNK knockdown BEL-7404 cells. The pathway of tRNA charging with Z-score = -3 was significantly inhibited in BEL-7404 cells with IDNK knockdown. Conclusion IDNK plays a key role in the proliferation and apoptosis of HCC cells. IDNK may be a candidate therapeutic target for HCC.
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Affiliation(s)
- Xiao-Min Wu
- Department of Integrated Traditional Chinese and Western Medicine Oncology, Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu 214062, People's Republic of China
| | - Cheng Jin
- Department of Hepatobiliary Surgery, Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu 214041, People's Republic of China
| | - Yuan-Long Gu
- Department of Hepatobiliary Surgery, Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu 214041, People's Republic of China
| | - Wu-Qiang Chen
- Department of Hepatobiliary Surgery, Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu 214041, People's Republic of China
| | - Mao-Qun Zhu
- Department of Hepatobiliary Surgery, Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu 214041, People's Republic of China
| | - Shuo Zhang
- Department of Hepatobiliary Surgery, Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu 214041, People's Republic of China
| | - Zhen Zhang
- Department of Integrated Traditional Chinese and Western Medicine Oncology, Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu 214062, People's Republic of China
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Dong L, Lv M, Gao X, Zhang L, Rogers M, Cao Y, Lan Y. In vitrogastrointestinal digestibility of phytosterol oleogels: influence of self-assembled microstructures on emulsification efficiency and lipase activity. Food Funct 2020; 11:9503-9513. [DOI: 10.1039/d0fo01642j] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The objective of this study was to investigate the influence of a self-assembled microstructure on lipid digestibility of phytosterol (γ-oryzanol and β-sitosterol) oleogels, including the oil emulsification process and further lipolysis.
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Affiliation(s)
- Lulu Dong
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods
- College of Food Sciences
- South China Agricultural University
- Guangzhou
- P.R. China
| | - Muwen Lv
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods
- College of Food Sciences
- South China Agricultural University
- Guangzhou
- P.R. China
| | - Xiangyang Gao
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods
- College of Food Sciences
- South China Agricultural University
- Guangzhou
- P.R. China
| | - Luping Zhang
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods
- College of Food Sciences
- South China Agricultural University
- Guangzhou
- P.R. China
| | - Michael Rogers
- Department of Food Science
- University of Guelph
- Guelph
- Canada
| | - Yong Cao
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods
- College of Food Sciences
- South China Agricultural University
- Guangzhou
- P.R. China
| | - Yaqi Lan
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods
- College of Food Sciences
- South China Agricultural University
- Guangzhou
- P.R. China
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11
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Singh J, Suh EH, Sharma G, Khemtong C, Sherry AD, Kovacs Z. Probing carbohydrate metabolism using hyperpolarized 13 C-labeled molecules. NMR IN BIOMEDICINE 2019; 32:e4018. [PMID: 30474153 PMCID: PMC6579721 DOI: 10.1002/nbm.4018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 08/03/2018] [Accepted: 08/11/2018] [Indexed: 05/05/2023]
Abstract
Glycolysis is a fundamental metabolic process in all organisms. Anomalies in glucose metabolism are linked to various pathological conditions. In particular, elevated aerobic glycolysis is a characteristic feature of rapidly growing cells. Glycolysis and the closely related pentose phosphate pathway can be monitored in real time by hyperpolarized 13 C-labeled metabolic substrates such as 13 C-enriched, deuterated D-glucose derivatives, [2-13 C]-D-fructose, [2-13 C] dihydroxyacetone, [1-13 C]-D-glycerate, [1-13 C]-D-glucono-δ-lactone and [1-13 C] pyruvate in healthy and diseased tissues. Elevated glycolysis in tumors (the Warburg effect) was also successfully imaged using hyperpolarized [U-13 C6 , U-2 H7 ]-D-glucose, while the size of the preexisting lactate pool can be measured by 13 C MRS and/or MRI with hyperpolarized [1-13 C]pyruvate. This review summarizes the application of various hyperpolarized 13 C-labeled metabolites to the real-time monitoring of glycolysis and related metabolic processes in normal and diseased tissues.
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Affiliation(s)
- Jaspal Singh
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Eul Hyun Suh
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Gaurav Sharma
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Chalermchai Khemtong
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - A. Dean Sherry
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Zoltan Kovacs
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
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12
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Schittenhelm D, Neuss-Radu M, Verma N, Pink M, Schmitz-Spanke S. ROS and pentose phosphate pathway: mathematical modelling of the metabolic regulation in response to xenobiotic-induced oxidative stress and the proposed Impact of the gluconate shunt. Free Radic Res 2019; 53:979-992. [PMID: 31476923 DOI: 10.1080/10715762.2019.1660777] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Elevated intracellular levels of reactive oxygen species (ROS), e.g. resulting from exposure to xenobiotics, can cause severe damages. Antioxidant defence mechanisms, which involve regulation of enzyme activities, protect cells to a certain extent. Nevertheless, continuous or increased exposure can overwhelm this system resulting in an adverse cellular state. To simulate exposure scenarios and to investigate the transition to an adverse cellular state, a mathematical model for the dynamics of ROS in response to xenobiotic-induced oxidative stress has been developed. It is based on exposure experiments of human urothelial cells (RT4) to the nitrated polycyclic aromatic hydrocarbon 3-nitrobenzanthrone (3-NBA), a component of diesel engine exhaust, and takes into account the following metabolic pathways of the antioxidant defence system: glutathione redox cycle scavenging directly ROS, the pentose phosphate pathway and the gluconate shunt as NADPH supplier and the beginning of glycolysis. In addition, ROS generation due to the bioactivation of 3-NBA has been implemented. The regulation of enzyme activities plays an important role in the presented mathematical model. The in silico model consists of ordinary differential equations on the basis of enzyme kinetics and mass action for the metabolism of 3-NBA. Parameters are either estimated from performed in vitro experiments via least-squares fitting or obtained from the literature. The results underline the importance of the pentose phosphate pathway to cope with oxidative stress and suggest an important role of the gluconate shunt during low-dose exposure.
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Affiliation(s)
- Doris Schittenhelm
- Department of Mathematics, Friedrich-Alexander-Universität Erlangen-Nürnberg , Erlangen , Germany
| | - Maria Neuss-Radu
- Department of Mathematics, Friedrich-Alexander-Universität Erlangen-Nürnberg , Erlangen , Germany
| | - Nisha Verma
- Institute and Outpatient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander-Universität Erlangen-Nürnberg , Erlangen , Germany
| | - Mario Pink
- Institute and Outpatient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander-Universität Erlangen-Nürnberg , Erlangen , Germany
| | - Simone Schmitz-Spanke
- Institute and Outpatient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander-Universität Erlangen-Nürnberg , Erlangen , Germany
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13
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Wang Y, Guan J, Di Trani JM, Auclair K, Mittermaier AK. Inhibition and Activation of Kinases by Reaction Products: A Reporter-Free Assay. Anal Chem 2019; 91:11803-11811. [PMID: 31426630 DOI: 10.1021/acs.analchem.9b02456] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Kinases are widely distributed in nature and are implicated in many human diseases. Thus, an understanding of their activity and regulation is of fundamental importance. Several kinases are known to be inhibited by ADP. However, thorough investigation of this phenomenon is hampered by the lack of a simple and effective assay for studying this inhibition. We now present a quick, general approach for measuring the effects of reaction products on kinase activity. The method, based on isothermal titration calorimetry, is the first universal, reporter-free, continuous assay for probing kinase inhibition or activation by ADP. In applications to an aminoglycoside phosphotransferase [APH(3')-IIIa] and pantothenate kinases from Escherichia coli (EcPanK) and Pseudomonas aeruginosa (PaPanK), we found ADP to be an efficient inhibitor of all three kinases, with inhibition constant (Ki) values similar to or lower than the Michaelis-Menten constant (Km) values of ATP. Interestingly, ADP was an activator at low concentrations and an inhibitor at high concentrations for EcPanK. This unusual effect was quantitatively modeled and attributed to cooperative interactions between the two subunits of the dimeric enzyme. Importantly, our results suggest that, at typical bacterial intracellular concentrations of ATP and ADP (approximately 1.5 mM and 180 μM, respectively), all three kinases are partially inhibited by ADP, allowing enzyme activity to rapidly respond to changes in the levels of both metabolites.
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Affiliation(s)
- Yun Wang
- Department of Chemistry , McGill University , 801 Sherbrooke Street West , Montreal , Quebec , Canada H3A 0B8
| | - Jinming Guan
- Department of Chemistry , McGill University , 801 Sherbrooke Street West , Montreal , Quebec , Canada H3A 0B8
| | - Justin M Di Trani
- Department of Chemistry , McGill University , 801 Sherbrooke Street West , Montreal , Quebec , Canada H3A 0B8
| | - Karine Auclair
- Department of Chemistry , McGill University , 801 Sherbrooke Street West , Montreal , Quebec , Canada H3A 0B8
| | - Anthony K Mittermaier
- Department of Chemistry , McGill University , 801 Sherbrooke Street West , Montreal , Quebec , Canada H3A 0B8
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14
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Hepatic metabolic adaptation in a murine model of glutathione deficiency. Chem Biol Interact 2019; 303:1-6. [PMID: 30794799 DOI: 10.1016/j.cbi.2019.02.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 02/03/2019] [Accepted: 02/16/2019] [Indexed: 11/23/2022]
Abstract
Glutathione (GSH), the most abundant cellular non-protein thiol, plays a pivotal role in hepatic defense mechanisms against oxidative damage. Despite a strong association between disrupted GSH homeostasis and liver diseases of various etiologies, it was shown that GSH-deficient glutamate-cysteine ligase modifier subunit (Gclm)-null mice are protected against fatty liver development induced by a variety of dietary and environmental insults. The biochemical mechanisms underpinning this protective phenotype have not been clearly defined. The purpose of the current study was to characterize the intrinsic metabolic signature in the livers from GSH deficient Gclm-null mice. Global profiling of hepatic polar metabolites revealed a spectrum of changes in amino acids and metabolites derived from fatty acids, glucose and nucleic acids due to the loss of GCLM. Overall, the observed low GSH-driven metabolic changes represent metabolic adaptations, including elevations in glutamate, aspartate, acetyl-CoA and gluconate, which are beneficial for the maintenance of cellular redox and metabolic homeostasis.
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15
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Wolahan SM, Lebby E, Mao HC, McArthur D, Real C, Vespa P, Braas D, Glenn TC. Novel Metabolomic Comparison of Arterial and Jugular Venous Blood in Severe Adult Traumatic Brain Injury Patients and the Impact of Pentobarbital Infusion. J Neurotrauma 2018; 36:212-221. [PMID: 29901425 DOI: 10.1089/neu.2018.5674] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Treatment of severe traumatic brain injury (TBI) in the intensive care unit focuses on controlling intracranial pressure, ensuring sufficient cerebral perfusion, and monitoring for secondary injuries. However, there are limited prognostic tools and no biomarkers or tests of the evolving neuropathology. Metabolomics has the potential to be a powerful tool to indirectly monitor evolving dysfunctional metabolism. We compared metabolite levels in simultaneously collected arterial and jugular venous samples in acute TBI patients undergoing intensive care as well as in healthy control volunteers. Our results show that, first, many circulating metabolites are decreased in TBI patients compared with healthy controls days after injury; both proline and hydroxyproline were depleted by ≥60% compared with healthy controls, as was gluconate. Second, both arterial and jugular venous plasma metabolomic analysis separates TBI patients from healthy controls and shows that distinct combinations of metabolites are driving the group separation in the two blood types. Third, TBI patients under heavy sedation with pentobarbital at the time of blood collection were discernibly different from patients not receiving pentobarbital. These results highlight the importance of accounting for medications in metabolomics analysis. Jugular venous plasma metabolomics shows potential as a minimally invasive tool to identify and study dysfunctional cerebral metabolism after TBI.
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Affiliation(s)
- Stephanie M Wolahan
- 1 UCLA Brain Injury Research Center and Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Elliott Lebby
- 1 UCLA Brain Injury Research Center and Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Howard C Mao
- 1 UCLA Brain Injury Research Center and Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - David McArthur
- 1 UCLA Brain Injury Research Center and Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Courtney Real
- 1 UCLA Brain Injury Research Center and Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Paul Vespa
- 1 UCLA Brain Injury Research Center and Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Daniel Braas
- 2 UCLA Metabolomics Center, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Thomas C Glenn
- 1 UCLA Brain Injury Research Center and Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, California
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16
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Falconer RJ. Applications of isothermal titration calorimetry - the research and technical developments from 2011 to 2015. J Mol Recognit 2016; 29:504-15. [PMID: 27221459 DOI: 10.1002/jmr.2550] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 04/05/2016] [Accepted: 04/14/2016] [Indexed: 12/12/2022]
Abstract
Isothermal titration calorimetry is a widely used biophysical technique for studying the formation or dissociation of molecular complexes. Over the last 5 years, much work has been published on the interpretation of isothermal titration calorimetry (ITC) data for single binding and multiple binding sites. As over 80% of ITC papers are on macromolecules of biological origin, this interpretation is challenging. Some researchers have attempted to link the thermodynamics constants to events at the molecular level. This review highlights work carried out using binding sites characterized using x-ray crystallography techniques that allow speculation about individual bond formation and the displacement of individual water molecules during ligand binding and link these events to the thermodynamic constants for binding. The review also considers research conducted with synthetic binding partners where specific binding events like anion-π and π-π interactions were studied. The revival of assays that enable both thermodynamic and kinetic information to be collected from ITC data is highlighted. Lastly, published criticism of ITC research from a physical chemistry perspective is appraised and practical advice provided for researchers unfamiliar with thermodynamics and its interpretation. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Robert J Falconer
- Department of Chemical and Biological Engineering, ChELSI Institute, University of Sheffield, Sheffield, S1 3JD, UK.
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