1
|
Al-U'datt DGF, Tranchant CC, Al-Dwairi A, AlQudah M, Al-Shboul O, Hiram R, Allen BG, Jaradat S, Alqbelat J, Abu-Zaiton AS. Implications of enigmatic transglutaminase 2 (TG2) in cardiac diseases and therapeutic developments. Biochem Pharmacol 2022; 201:115104. [PMID: 35617996 DOI: 10.1016/j.bcp.2022.115104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 05/18/2022] [Accepted: 05/18/2022] [Indexed: 01/07/2023]
Abstract
Cardiac diseases are the leading cause of mortality and morbidity worldwide. Mounting evidence suggests that transglutaminases (TGs), tissue TG (TG2) in particular, are involved in numerous molecular responses underlying the pathogenesis of cardiac diseases. The TG family has several intra- and extracellular functions in the human body, including collagen cross-linking, angiogenesis, cell growth, differentiation, migration, adhesion as well as survival. TGs are thiol- and calcium-dependent acyl transferases that catalyze the formation of a covalent bond between the γ-carboxamide group of a glutamine residue and an amine group, thus increasing the stability, rigidity, and stiffness of the myocardial extracellular matrix (ECM). Excessive accumulation of cross-linked collagen leads to increase myocardial stiffness and fibrosis. Beyond TG2 extracellular protein cross-linking action, mounting evidence suggests that this pleiotropic TG isozyme may also promote fibrotic diseases through cell survival and profibrotic pathway activation at the signaling, transcriptional and translational levels. Due to its multiple functions and localizations, TG2 fulfils critical yet incompletely understood roles in myocardial fibrosis and associated heart diseases, such as cardiac hypertrophy, heart failure, and age-related myocardial stiffness under several conditions. This review summarizes current knowledge and existing gaps regarding the ECM-dependent and ECM-independent roles of TG2 and highlights the therapeutic prospects of targeting TG2 to treat cardiac diseases.
Collapse
Affiliation(s)
- Doa'a G F Al-U'datt
- Department of Physiology and Biochemistry, Faculty of Medicine, Jordan University of Science and Technology, Irbid, 22110, Jordan.
| | - Carole C Tranchant
- School of Food Science, Nutrition and Family Studies, Faculty of Health Sciences and Community Services, Université de Moncton, New Brunswick, Canada
| | - Ahmed Al-Dwairi
- Department of Physiology and Biochemistry, Faculty of Medicine, Jordan University of Science and Technology, Irbid, 22110, Jordan
| | - Mohammad AlQudah
- Department of Physiology and Biochemistry, Faculty of Medicine, Jordan University of Science and Technology, Irbid, 22110, Jordan
| | - Othman Al-Shboul
- Department of Physiology and Biochemistry, Faculty of Medicine, Jordan University of Science and Technology, Irbid, 22110, Jordan
| | - Roddy Hiram
- Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada; Department of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Bruce G Allen
- Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada; Department of Medicine, Université de Montréal, Montreal, Quebec, Canada; Department of Pharmacology and Physiology, Université de Montréal, Montreal, Quebec, Canada; Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Saied Jaradat
- Princess Haya Biotechnology Center, Jordan University of Science and Technology, Irbid, 22110, Jordan
| | - Jenan Alqbelat
- Department of Physiology and Biochemistry, Faculty of Medicine, Jordan University of Science and Technology, Irbid, 22110, Jordan
| | - Ahmed S Abu-Zaiton
- Department of Biological Sciences, Al al-bayt University, Al-Mafraq, Jordan
| |
Collapse
|
2
|
Abstract
Growing evidence supports a potential link between dietary gluten intake and neurodegenerative disease in susceptible populations. Observational data supporting this link are described along with interventional study data evaluating the effects of restricting gluten from the diet in patients with neurologic disorders. Suggested underlying mechanisms between gluten intake and neurodegeneration are discussed.
Collapse
Affiliation(s)
- Ashok Philip
- Ashok Philip, Director of Assessment and Professor of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, College of Pharmacy 4301 W. Markham
- Little Rock, AR 72205, USA. e-mail:
| | | |
Collapse
|
3
|
Pearse DD, Ghosh M. Neuronal and endothelial transglutaminase-2 expression in experimental autoimmune encephalomyelitis and multiple sclerosis. Neural Regen Res 2021; 17:1471-1472. [PMID: 34916421 PMCID: PMC8771117 DOI: 10.4103/1673-5374.330598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- Damien D Pearse
- Miami Project to Cure Paralysis; Department of Neurological Surgery; Neuroscience Program, Interdisciplinary Stem Cell Institute; Department of Veterans Affairs, Veterans Affairs Medical Center, Miami, FL, USA
| | - Mousumi Ghosh
- Miami Project to Cure Paralysis; Department of Neurological Surgery, University of Miami Miller School of Medicine; Department of Veterans Affairs, Veterans Affairs Medical Center, Miami, FL, USA
| |
Collapse
|
4
|
Affiliation(s)
- Yan Y Sanders
- Department of Medicine University of Alabama at Birmingham Birmingham, Alabama
| | - Gang Liu
- Department of Medicine University of Alabama at Birmingham Birmingham, Alabama
| |
Collapse
|
5
|
Dietary Gluten and Neurodegeneration: A Case for Preclinical Studies. Int J Mol Sci 2020; 21:ijms21155407. [PMID: 32751379 PMCID: PMC7432597 DOI: 10.3390/ijms21155407] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/23/2020] [Accepted: 07/24/2020] [Indexed: 12/11/2022] Open
Abstract
Although celiac disease (CD) is an autoimmune disease that primarily involves the intestinal tract, mounting evidence suggests that a sizeable number of patients exhibit neurological deficits. About 40% of the celiac patients with neurological manifestations have circulating antibodies against neural tissue transglutaminase-6 (tTG6). While early diagnosis and strict adherence to a gluten-free diet (GFD) have been recommended to prevent neurological dysfunction, better therapeutic strategies are needed to improve the overall quality of life. Dysregulation of the microbiota-gut-brain axis, presence of anti-tTG6 antibodies, and epigenetic mechanisms have been implicated in the pathogenesis. It is also possible that circulating or gut-derived extracellular structures and including biomolecular condensates and extracellular vesicles contribute to disease pathogenesis. There are several avenues for shaping the dysregulated gut homeostasis in individuals with CD, non-celiac gluten sensitivity (NCGS) and/or neurodegeneration. In addition to GFD and probiotics, nutraceuticals, such as phyto and synthetic cannabinoids, represent a new approach that could shape the host microbiome towards better prognostic outcomes. Finally, we provide a data-driven rationale for potential future pre-clinical research involving non-human primates (NHPs) to investigate the effect of nutraceuticals, such as phyto and synthetic cannabinoids, either alone or in combination with GFD to prevent/mitigate dietary gluten-induced neurodegeneration.
Collapse
|
6
|
Currò M, Ferlazzo N, Giunta ML, Montalto AS, Russo T, Arena S, Impellizzeri P, Caccamo D, Romeo C, Ientile R. Hypoxia-Dependent Expression of TG2 Isoforms in Neuroblastoma Cells as Consequence of Different MYCN Amplification Status. Int J Mol Sci 2020; 21:ijms21041364. [PMID: 32085516 PMCID: PMC7072980 DOI: 10.3390/ijms21041364] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 02/07/2020] [Accepted: 02/15/2020] [Indexed: 12/13/2022] Open
Abstract
Transglutaminase 2 (TG2) is a multifunctional enzyme and two isoforms, TG2-L and TG2-S, exerting opposite effects in the regulation of cell death and survival, have been revealed in cancer tissues. Notably, in cancer cells a hypoxic environment may stimulate tumor growth, invasion and metastasis. Here we aimed to characterize the role of TG2 isoforms in neuroblastoma cell fate under hypoxic conditions. The mRNA levels of TG2 isoforms, hypoxia-inducible factor (HIF)-1α, p16, cyclin D1 and B1, as well as markers of cell proliferation/death, DNA damage, and cell cycle were examined in SH-SY5Y (non-MYCN-amplified) and IMR-32 (MYCN-amplified) neuroblastoma cells in hypoxia/reoxygenation conditions. The exposure to hypoxia induced the up-regulation of HIF-1α in both cell lines. Hypoxic conditions caused the up-regulation of TG2-S and the reduction of cell viability/proliferation associated with DNA damage in SH-SY5Y cells, while in IMR-32 did not produce DNA damage, and increased the levels of both TG2 isoforms and proliferation markers. Different cell response to hypoxia can be mediated by TG2 isoforms in function of MYCN amplification status. A better understanding of the role of TG2 isoforms in neuroblastoma may open new venues in a diagnostic and therapeutic perspective.
Collapse
Affiliation(s)
- Monica Currò
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, 98125 Messina, Italy; (M.C.); (N.F.); (M.L.G.); (D.C.)
| | - Nadia Ferlazzo
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, 98125 Messina, Italy; (M.C.); (N.F.); (M.L.G.); (D.C.)
| | - Maria Laura Giunta
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, 98125 Messina, Italy; (M.C.); (N.F.); (M.L.G.); (D.C.)
| | - Angela Simona Montalto
- Department of Human Pathology of Adult and Childhood “Gaetano Barresi,” University of Messina, 98125 Messina, Italy; (A.S.M.); (T.R.); (S.A.); (P.I.); (C.R.)
| | - Tiziana Russo
- Department of Human Pathology of Adult and Childhood “Gaetano Barresi,” University of Messina, 98125 Messina, Italy; (A.S.M.); (T.R.); (S.A.); (P.I.); (C.R.)
| | - Salvatore Arena
- Department of Human Pathology of Adult and Childhood “Gaetano Barresi,” University of Messina, 98125 Messina, Italy; (A.S.M.); (T.R.); (S.A.); (P.I.); (C.R.)
| | - Pietro Impellizzeri
- Department of Human Pathology of Adult and Childhood “Gaetano Barresi,” University of Messina, 98125 Messina, Italy; (A.S.M.); (T.R.); (S.A.); (P.I.); (C.R.)
| | - Daniela Caccamo
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, 98125 Messina, Italy; (M.C.); (N.F.); (M.L.G.); (D.C.)
| | - Carmelo Romeo
- Department of Human Pathology of Adult and Childhood “Gaetano Barresi,” University of Messina, 98125 Messina, Italy; (A.S.M.); (T.R.); (S.A.); (P.I.); (C.R.)
| | - Riccardo Ientile
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, 98125 Messina, Italy; (M.C.); (N.F.); (M.L.G.); (D.C.)
- Correspondence:
| |
Collapse
|
7
|
Kramer K, Yeboah-Awudzi M, Magazine N, King JM, Xu Z, Losso JN. Procyanidin B2 rich cocoa extracts inhibit inflammation in Caco-2 cell model of in vitro celiac disease by down-regulating interferon-gamma- or gliadin peptide 31-43-induced transglutaminase-2 and interleukin-15. J Funct Foods 2019. [DOI: 10.1016/j.jff.2019.03.039] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
|
8
|
Wells EA, Anderson MA, Zeczycki TN. 15(V/K) kinetic isotope effect and steady-state kinetic analysis for the transglutaminase 2 catalyzed deamidation and transamidation reactions. Arch Biochem Biophys 2018; 643:57-61. [PMID: 29477769 DOI: 10.1016/j.abb.2018.02.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 02/18/2018] [Accepted: 02/19/2018] [Indexed: 10/18/2022]
Abstract
The Ca2+-dependent deamidation and transamidation activities of transglutaminase 2 (TG2) are important to numerous physiological and pathological processes. Herein, we have examined the steady-state kinetics and 15(V/K) kinetic isotope effects (KIEs) for the TG2-catalyzed deamidation and transamidation of N-Benzyloxycarbonyl-l-Glutaminylglycine (Z-Gln-Gly) using putrescine as the acyl acceptor substrate. Kinetic parameters determined from initial velocity plots are consistent with previously proposed mechanisms. Significant differences in the 15(V/K) KIEs on NH3 release determined for the deamidation (0.2%) and the transamidation (2.3%) of Z-Gln-Gly suggest the rate-limiting steps of TG2 active site acylation are dependent on the presence of the acyl acceptor. We propose a plausible mechanistic explanation where substrate-induced conformational changes may play a role in promoting catalysis.
Collapse
Affiliation(s)
- Evan A Wells
- Department of Biochemistry and Molecular Biology and the East Carolina Diabetes and Obesity Institute, Brody School of Medicine at East Carolina University, Greenville, NC, United States
| | - Mark A Anderson
- Department of Biochemistry, University of Wisconsin, Madison, WI, United States
| | - Tonya N Zeczycki
- Department of Biochemistry and Molecular Biology and the East Carolina Diabetes and Obesity Institute, Brody School of Medicine at East Carolina University, Greenville, NC, United States.
| |
Collapse
|
9
|
Palanski BA, Khosla C. Cystamine and Disulfiram Inhibit Human Transglutaminase 2 via an Oxidative Mechanism. Biochemistry 2018; 57:3359-3363. [PMID: 29570977 DOI: 10.1021/acs.biochem.8b00204] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The catalytic activity of transglutaminase 2 (TG2), a ubiquitously expressed mammalian enzyme, is regulated by multiple post-translational mechanisms. Because elevated activity of TG2 in the extracellular matrix is associated with organ-specific diseases such as celiac disease and renal fibrosis, there is growing therapeutic interest in inhibitors of this enzyme. Cystamine, a symmetric disulfide compound, is one of the earliest reported TG2 inhibitors. Despite its widespread use as a tool compound to block TG2 activity in vitro and in vivo, its mechanism of action has remained unclear. Here, we demonstrate that cystamine irreversibly inhibits human TG2 ( kinh/ Ki = 1.2 mM-1 min-1) via a mechanism fundamentally distinct from those proposed previously. Through mass spectrometric disulfide mapping and site-directed mutagenesis, we show that cystamine promotes the formation of a physiologically relevant disulfide bond between Cys370 and Cys371 that allosterically abrogates the catalytic activity of human TG2. This discovery led us to evaluate clinically useful thiol → disulfide oxidants for TG2 inhibitory activity. It is demonstrated that disulfiram, a relatively safe oral thiuram disulfide, is a fairly potent TG2 inhibitor ( kinh/ Ki = 8.3 mM-1 min-1) and may therefore provide a practical tool for clinically validating this emerging therapeutic target in intestinal disorders such as celiac disease.
Collapse
|
10
|
Song M. Recent developments in small molecule therapies for renal cell carcinoma. Eur J Med Chem 2017; 142:383-392. [DOI: 10.1016/j.ejmech.2017.08.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/27/2017] [Accepted: 08/02/2017] [Indexed: 12/23/2022]
|
11
|
β 2 -adrenoceptor-induced modulation of transglutaminase 2 transamidase activity in cardiomyoblasts. Eur J Pharmacol 2017; 813:105-121. [DOI: 10.1016/j.ejphar.2017.07.043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/24/2017] [Accepted: 07/24/2017] [Indexed: 12/12/2022]
|
12
|
Song M, Hwang H, Im CY, Kim SY. Recent Progress in the Development of Transglutaminase 2 (TGase2) Inhibitors. J Med Chem 2016; 60:554-567. [PMID: 28122456 DOI: 10.1021/acs.jmedchem.6b01036] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Transglutaminase 2 (TGase2, TG2) activity has been implicated in the pathogenesis of a number of unrelated disorders, including celiac, neurological, and renal diseases, and various forms of cancer. It has been suggested that TGase2 activity, such as cross-linking, deamidation, and GTP-related activity, is associated with each disease. Continuing efforts to develop small molecule TG2 inhibitors are ongoing. To develop a new class of TG2 inhibitors, the factors impeding the development of TG2 inhibitors have been identified. Additionally, the conformational effect of TG2 enzyme in regard to its pathological roles, in vitro screening methods, recently discovered TG2 inhibitors, and preclinical evaluations are discussed with a brief summary of current TG2 inhibitor pipelines under the clinical setting.
Collapse
Affiliation(s)
- Minsoo Song
- New Drug Development Center (NDDC), Daegu-Gyeongbuk Medical Innovation Foundation (DGMIF) , 80 Cheombok-ro, Dong-gu, Daegu 701-310, Korea
| | - Hayoung Hwang
- New Drug Development Center (NDDC), Daegu-Gyeongbuk Medical Innovation Foundation (DGMIF) , 80 Cheombok-ro, Dong-gu, Daegu 701-310, Korea
| | - Chun Young Im
- New Drug Development Center (NDDC), Daegu-Gyeongbuk Medical Innovation Foundation (DGMIF) , 80 Cheombok-ro, Dong-gu, Daegu 701-310, Korea
| | - Soo-Youl Kim
- Cancer Cell and Molecular Biology Branch, Research Institute, National Cancer Center , Goyang-si, Gyeonggi-do 410-769, Korea
| |
Collapse
|
13
|
Wodtke R, Schramm G, Pietzsch J, Pietsch M, Löser R. Synthesis and Kinetic Characterisation of Water-Soluble Fluorogenic Acyl Donors for Transglutaminase 2. Chembiochem 2016; 17:1263-81. [DOI: 10.1002/cbic.201600048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Indexed: 12/16/2022]
Affiliation(s)
- Robert Wodtke
- Helmholtz-Zentrum Dresden-Rossendorf; Institut für Radiopharmazeutische Krebsforschung; Bautzner Landstrasse 400 01328 Dresden Germany
- Fachrichtung Chemie und Lebensmittelchemie; Technische Universität Dresden; Mommsenstrasse 4 01062 Dresden Germany
| | - Georg Schramm
- Helmholtz-Zentrum Dresden-Rossendorf; Institut für Radiopharmazeutische Krebsforschung; Bautzner Landstrasse 400 01328 Dresden Germany
- Department of Imaging and Pathology; KU Leuven; UZ Herestraat 49 3000 Leuven Belgium
| | - Jens Pietzsch
- Helmholtz-Zentrum Dresden-Rossendorf; Institut für Radiopharmazeutische Krebsforschung; Bautzner Landstrasse 400 01328 Dresden Germany
- Fachrichtung Chemie und Lebensmittelchemie; Technische Universität Dresden; Mommsenstrasse 4 01062 Dresden Germany
| | - Markus Pietsch
- Zentrum für Pharmakologie, Medizinische Fakultät; Universität zu Köln; Gleueler Strasse 24 50931 Köln Germany
| | - Reik Löser
- Helmholtz-Zentrum Dresden-Rossendorf; Institut für Radiopharmazeutische Krebsforschung; Bautzner Landstrasse 400 01328 Dresden Germany
- Fachrichtung Chemie und Lebensmittelchemie; Technische Universität Dresden; Mommsenstrasse 4 01062 Dresden Germany
| |
Collapse
|
14
|
Vyas FS, Hargreaves AJ, Bonner PL, Boocock DJ, Coveney C, Dickenson JM. A1 adenosine receptor-induced phosphorylation and modulation of transglutaminase 2 activity in H9c2 cells: A role in cell survival. Biochem Pharmacol 2016; 107:41-58. [DOI: 10.1016/j.bcp.2016.03.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 03/17/2016] [Indexed: 12/25/2022]
|
15
|
Singh G, Zhang J, Ma Y, Cerione RA, Antonyak MA. The Different Conformational States of Tissue Transglutaminase Have Opposing Affects on Cell Viability. J Biol Chem 2016; 291:9119-32. [PMID: 26893378 PMCID: PMC4861479 DOI: 10.1074/jbc.m115.699108] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 02/11/2016] [Indexed: 02/06/2023] Open
Abstract
Tissue transglutaminase (tTG) is an acyltransferase/GTP-binding protein that contributes to the development of various diseases. In human cancer cells, tTG activates signaling pathways that promote cell growth and survival, whereas in other disorders (i.e. neurodegeneration), overexpression of tTG enhances cell death. Therefore, it is important to understand how tTG is differentially regulated and functioning to promote diametrically distinct cellular outcomes. Previous structural studies revealed that tTG adopts either a nucleotide-bound closed conformation or a transamidation-competent open conformation. Here we provide evidence showing that these different conformational states determine whether tTG promotes, or is detrimental to, cell survival, with the open conformation of the protein being responsible for inducing cell death. First, we demonstrate that a nucleotide binding-defective form of tTG, which has previously been shown to induce cell death, assumes an open conformation in solution as assessed by an enhanced sensitivity to trypsin digestion and by small angle x-ray scattering (SAXS) analysis. We next identify two pairs of intramolecular hydrogen bonds that, based on existing x-ray structures, are predicted to form between the most C-terminal β-barrel domain and the catalytic core domain of tTG. By disrupting these hydrogen bonds, we are able to generate forms of tTG that constitutively assume an open conformation and induce apoptosis. These findings provide important insights into how tTG participates in the pathogenesis of neurodegenerative diseases, particularly with regard to the actions of a C-terminal truncated form of tTG (TG-Short) that has been linked to such disorders and induces apoptosis by assuming an open-like conformation.
Collapse
Affiliation(s)
| | | | - Yilun Ma
- From the Department of Molecular Medicine and
| | - Richard A Cerione
- From the Department of Molecular Medicine and the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
| | | |
Collapse
|
16
|
|
17
|
Almami I, Dickenson JM, Hargreaves AJ, Bonner PLR. Modulation of transglutaminase 2 activity in H9c2 cells by PKC and PKA signalling: a role for transglutaminase 2 in cytoprotection. Br J Pharmacol 2015; 171:3946-60. [PMID: 24821315 DOI: 10.1111/bph.12756] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 04/15/2014] [Accepted: 04/22/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE Tissue transglutaminase (TG2) has been shown to mediate cell survival in many cell types. In this study, we investigated whether the role of TG2 in cytoprotection was mediated by the activation of PKA and PKC in cardiomyocyte-like H9c2 cells. EXPERIMENTAL APPROACH H9c2 cells were extracted following stimulation with phorbol-12-myristate-13-acetate (PMA) and forskolin. Transglutaminase activity was determined using an amine incorporating and a protein crosslinking assay. The presence of TG isoforms (TG1, 2, 3) was determined using Western blot analysis. The role of TG2 in PMA- and forskolin-induced cytoprotection was investigated by monitoring H₂O₂-induced oxidative stress in H9c2 cells. KEY RESULTS Western blotting showed TG2 >> TG1 protein expression but no detectable TG3. The amine incorporating activity of TG2 in H9c2 cells increased in a time and concentration-dependent manner following stimulation with PMA and forskolin. PMA and forskolin-induced TG2 activity was blocked by PKC (Ro 31-8220) and PKA (KT 5720 and Rp-8-Cl-cAMPS) inhibitors respectively. The PMA- and forskolin-induced increases in TG2 activity were attenuated by the TG2 inhibitors Z-DON and R283. Immunocytochemistry revealed TG2-mediated biotin-X-cadaverine incorporation into proteins and proteomic analysis identified known (β-tubulin) and novel (α-actinin) protein substrates for TG2. Pretreatment with PMA and forskolin reversed H2 O2 -induced decrease in MTT reduction and release of LDH. TG2 inhibitors R283 and Z-DON blocked PMA- and forskolin-induced cytoprotection. CONCLUSIONS AND IMPLICATIONS TG2 activity was stimulated via PKA- and PKC-dependent signalling pathways in H9c2 cells These results suggest a role for TG2 in cytoprotection induced by these kinases.
Collapse
Affiliation(s)
- Ibtesam Almami
- School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | | | | | | |
Collapse
|
18
|
Inhibitors of tissue transglutaminase. Trends Pharmacol Sci 2014; 36:32-40. [PMID: 25500711 DOI: 10.1016/j.tips.2014.10.014] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 10/23/2014] [Accepted: 10/30/2014] [Indexed: 02/07/2023]
Abstract
Tissue transglutaminase (TG2) catalyzes the cross-linking of proteins by the formation of isopeptide bonds between glutamine (Gln) and lysine (Lys) side chains. Although TG2 is essential for the stabilization of the extracellular matrix, its unregulated activity has been implicated in celiac disease, fibrosis, and cancer metastasis, among other disorders. Given the importance and range of TG2-related pathologies, recent work has focused on the development of potent and selective inhibitors against TG2. In this review, we present the latest and most noteworthy irreversible and reversible inhibitors of TG2, and offer perspectives for the design of future inhibitors, in the hope that lead compounds with therapeutic potential may soon be discovered.
Collapse
|
19
|
Ientile R, Currò M, Caccamo D. Transglutaminase 2 and neuroinflammation. Amino Acids 2014; 47:19-26. [PMID: 25398223 DOI: 10.1007/s00726-014-1864-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 10/29/2014] [Indexed: 12/28/2022]
Abstract
Neuroinflammatory processes seem to play a pivotal role in various chronic neurodegenerative diseases, characterized also by the pathogenetic accumulation of specific protein aggregates. Several of these proteins have been shown to be substrates of transglutaminases, calcium-dependent enzymes that catalyze protein crosslinking reactions. However, it has recently been demonstrated that transglutaminase 2 (TG2) may also be involved in molecular mechanisms underlying inflammation. In the central nervous system, astrocytes and microglia are the cell types mainly involved in the inflammatory process. This review is focused on the increases of TG2 protein expression and enzyme activity that occur in astroglial, microglial and monocyte cell models in response to inflammatory stimuli. The transcription factor NF-κB is considered the main regulator of inflammation, being activated by a variety of stimuli including calcium influx, oxidative stress and inflammatory cytokines. Under these conditions, the over-expression of TG2 results in the sustained activation of NF-κB. Several findings emphasize the possible role of the TG2/NF-κB activation pathway in neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, multiple sclerosis and amyotrophic lateral sclerosis. Although further studies are needed to characterize the TG2/NF-κB cross-talk in monocytes/macrophages/microglia within the central nervous system, some results show that TG2 and NF-κB are co-localized in cell compartments. Together, evidence suggests that TG2 plays a role in neuroinflammation and contributes to the production of compounds that are potentially deleterious to neuronal cells.
Collapse
Affiliation(s)
- Riccardo Ientile
- Department of Biomedical Sciences and Morphological and Functional Imaging, University of Messina, AOU Policlinico "G. Martino", Via C. Valeria, Messina, Italy,
| | | | | |
Collapse
|
20
|
Abstract
Tissue transglutaminase (transglutaminase 2) is a multifunctional enzyme with many interesting properties resulting in versatile roles in both physiology and pathophysiology. Herein, the particular involvement of the enzyme in human diseases will be outlined with special emphasis on its role in cancer and in tissue interactions with biomaterials. Despite recent progress in unraveling the different cellular functions of transglutaminase 2, several questions remain. Transglutaminase 2 features in both confirmed and some still ambiguous roles within pathological conditions, raising interest in developing inhibitors and imaging probes which target this enzyme. One important prerequisite for identifying and characterizing such molecular tools are reliable assay methods to measure the enzymatic activity. This digest Letter will provide clarification about the various assay methods described to date, accompanied by a discussion of recent progress in the development of inhibitors and imaging probes targeting transglutaminase 2.
Collapse
|
21
|
Involvement of IL-13 and tissue transglutaminase in liver granuloma and fibrosis after schistosoma japonicum infection. Mediators Inflamm 2014; 2014:753483. [PMID: 25110399 PMCID: PMC4106180 DOI: 10.1155/2014/753483] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/20/2014] [Accepted: 06/05/2014] [Indexed: 11/24/2022] Open
Abstract
Schistosomiasis, one of the most devastating parasitic diseases, is caused by Schistosoma japonicum (Sj) infection resulting in serious liver fibrosis. Interleukin- (IL-) 13, which is produced by TH2 cells, is a critical profibrotic cytokine found in various organs, including the liver. Tissue transglutaminase (tTG), a group of multifunctional enzymes, serves a central function in the pathogenesis of chronic liver diseases. However, the relationship between IL-13, tTG, and liver fibrosis during Schistosoma infection has not been established. This study investigated the involvement of IL-13 and tTG in liver fibrogenesis during Sj infection in mice. Five weeks after Sj infection, granuloma and fibrosis development in the liver coincided with an increase in IL-13 and tTG in the liver and the upregulation of serum IL-13 in infected mice. Administration of cystamine, an inhibitor of tTG, abrogated the increase in both tTG and IL-13 in infected mice and ameliorated liver fibrogenesis and granuloma development. This result establishes a novel link among IL-13, tTG, and liver granuloma and fibrosis under Sj infection. Based on their important functions in liver fibrosis induced by Sj infection, IL-13 and tTG could be promising potential drug targets against schistosomiasis.
Collapse
|
22
|
Tarazi FI, Sahli ZT, Wolny M, Mousa SA. Emerging therapies for Parkinson's disease: from bench to bedside. Pharmacol Ther 2014; 144:123-33. [PMID: 24854598 DOI: 10.1016/j.pharmthera.2014.05.010] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 05/01/2014] [Indexed: 02/08/2023]
Abstract
The prevalence of Parkinson's disease (PD) increases with age and is projected to increase in parallel to the rising average age of the population. The disease can have significant health-related, social, and financial implications not only for the patient and the caregiver, but for the health care system as well. While the neuropathology of this neurodegenerative disorder is fairly well understood, its etiology remains a mystery, making it difficult to target therapy. The currently available drugs for treatment provide only symptomatic relief and do not control or prevent disease progression, and as a result patient compliance and satisfaction are low. Several emerging pharmacotherapies for PD are in different stages of clinical development. These therapies include adenosine A2A receptor antagonists, glutamate receptor antagonists, monoamine oxidase inhibitors, anti-apoptotic agents, and antioxidants such as coenzyme Q10, N-acetyl cysteine, and edaravone. Other emerging non-pharmacotherapies include viral vector gene therapy, microRNAs, transglutaminases, RTP801, stem cells and glial derived neurotrophic factor (GDNF). In addition, surgical procedures including deep brain stimulation, pallidotomy, thalamotomy and gamma knife surgery have emerged as alternative interventions for advanced PD patients who have completely utilized standard treatments and still suffer from persistent motor fluctuations. While several of these therapies hold much promise in delaying the onset of the disease and slowing its progression, more pharmacotherapies and surgical interventions need to be investigated in different stages of PD. It is hoped that these emerging therapies and surgical procedures will strengthen our clinical armamentarium for improved treatment of PD.
Collapse
Affiliation(s)
- F I Tarazi
- Department of Psychiatry and Neuroscience Program, Harvard Medical School, McLean Hospital, Belmont, MA 02478, USA.
| | - Z T Sahli
- Department of Psychiatry and Neuroscience Program, Harvard Medical School, McLean Hospital, Belmont, MA 02478, USA; School of Medicine, American University of Beirut, Beirut, Lebanon
| | - M Wolny
- The Pharmaceutical Research Institute at Albany College of Pharmacy and Health Sciences, Rensselaer, NY 12144, USA
| | - S A Mousa
- The Pharmaceutical Research Institute at Albany College of Pharmacy and Health Sciences, Rensselaer, NY 12144, USA
| |
Collapse
|
23
|
Anti-cancer effect of a quinoxaline derivative GK13 as a transglutaminase 2 inhibitor. J Cancer Res Clin Oncol 2013; 139:1279-94. [PMID: 23604466 DOI: 10.1007/s00432-013-1433-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 03/27/2013] [Indexed: 12/26/2022]
Abstract
PURPOSE Transglutaminase 2 (TGase 2), a cross-linking enzyme, plays an important role in both pro-survival and anti-apoptosis during oncogenesis. For instance, TGase 2 induces NF-κB activation through I-κBα polymerization, which leads to the increase of pro-survival factors such as BCl-2. TGase 2 also suppresses apoptosis via depletion of caspase 3 and cathepsin D. Therefore, a specific TGase 2 inhibitor may become a very useful treatment for cancer showing high levels of TGase 2 expression. METHODS By small-molecule library screening, we managed to locate a competitive TGase 2 inhibiting quinoxaline compound (GK13) from 50 other quinoxaline derivatives. The 50 compounds that were screened represent a thousand structurally diverse, potentially pharmaceutical heterocyclic compound libraries, including benzopyrans, oxadiazoles, thiadiazoles, and quinoxalines. By measuring GI50, TGI, and LC50 using SRB assay, GK13 was selected. RESULTS In vitro enzyme kinetics using guinea pig liver TGase 2 showed that IC50 value was about 16.4 E-6 M. GK13 inhibits TGase 2-mediated I-κBα polymerization in a dose-dependent manner. LC50 of GK13 showed greater efficacy as 4.3E-4 M than LC50 of doxorubicin that showed efficacy as 3.87E-3 M in NCC72 composing 11 tissue origins and 72 cancer cell lines. CONCLUSION GK13 showed a possibility that quinoxaline derivatives may be effective for anti-cancer activity via TGase 2 inhibition.
Collapse
|
24
|
Obara Y, Ishii K. [Multiple functions of Gh/transglutaminase 2]. Nihon Yakurigaku Zasshi 2013; 141:225. [PMID: 23575431 DOI: 10.1254/fpj.141.225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
|
25
|
Obara Y, Yanagihata Y, Abe T, Dafik L, Ishii K, Nakahata N. Gα(h)/transglutaminase-2 activity is required for maximal activation of adenylylcyclase 8 in human and rat glioma cells. Cell Signal 2012. [PMID: 23200849 DOI: 10.1016/j.cellsig.2012.11.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Gα(h) (or transglutaminase-2 (TG2)) is an atypical guanine nucleotide binding-protein that associates with G protein-coupled receptors. TG2 also exerts transglutaminase activity that catalyzes posttranslational protein cross-linking with the formation of ε-(γ-glutamyl) lysine or (γ-glutamyl) polyamine bonds. Here, the role of Gα(h)/TG2 in signal transduction in glial cells was examined in detail. In 1321N1 human astrocytoma cells that lack Gα(h)/TG2, overexpression of Gα(h)/TG2 caused an enhancement of cAMP accumulation stimulated with the β-adrenergic receptor agonist, isoproterenol, or the adenylylcyclase activator, forskolin. This cAMP-enhancement was reversed by the TG2 inhibitor, ERW1069. In rat C6 glioma cells that express endogenous Gα(h)/TG2, cAMP accumulation induced by isoproterenol or forskolin was significantly inhibited by overexpression of Gα(h)/TG2-C277V, a dominant-negative mutant that lacks transglutaminase activity, but was not inhibited by the Gα(h)/TG2-S171E mutant that cannot bind GTP/GDP. These results suggest Gα(h)/TG2 potentiates adenylylcyclase activity by its transglutaminase activity and not by its G-protein activity. Gα(h)/TG2 also increased the activities of the cAMP response element and interleukin-6 promoter, accompanied by an of cAMP in both glioma cells. Since adenylylcyclase 8 plays a major role in cAMP production, we focused on post-translational modification of adenylylcyclase 8 by Gα(h)/TG2. Adenylylcyclase 8 is expressed in both 1321N1 and C6 cells; however, Gα(h)/TG2 affected neither adenylylcyclase 8 expression levels, glycosylation, nor dimerization status. In contrast, pentylamine, a substrate of Gα(h)/TG2, was incorporated into adenylylcyclase 8 in a transglutaminase activity-dependent manner. Taking these results together, Gα(h)/TG2 promotes cAMP production accompanied by a modification of adenylylcyclase 8 in glioma cells.
Collapse
Affiliation(s)
- Yutaro Obara
- Department of Cellular Signaling, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| | | | | | | | | | | |
Collapse
|
26
|
Bayardo M, Punzi F, Bondar C, Chopita N, Chirdo F. Transglutaminase 2 expression is enhanced synergistically by interferon-γ and tumour necrosis factor-α in human small intestine. Clin Exp Immunol 2012; 168:95-104. [PMID: 22385244 DOI: 10.1111/j.1365-2249.2011.04545.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Transglutaminase 2 (TG2) is expressed ubiquitously, has multiple physiological functions and has also been associated with inflammatory diseases, neurodegenerative disorders, autoimmunity and cancer. In particular, TG2 is expressed in small intestine mucosa where it is up-regulated in active coeliac disease (CD). The aim of this work was to investigate the induction of TG2 expression by proinflammatory cytokines [interleukin (IL)-1, IL-6, tumour necrosis factor (TNF)-α, interferon (IFN)-γ and IL-15] and the signalling pathways involved, in human epithelial and monocytic cells and in intestinal tissue from controls and untreated CD patients. Here we report that IFN-γ was the most potent inducer of TG2 expression in the small intestinal mucosa and in four [Caco-2, HT-29, Calu-6 and human acute monocytic leukaemia cell line (THP-1)] of five cell lines tested. The combination of TNF-α and IFN-γ produced a strong synergistic effect. The use of selective inhibitors of signalling pathways revealed that induction of TG2 by IFN-γ was mediated by phosphoinositide 3-kinase (PI3K), while c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) were required for TNF-α activation. Quantitative polymerase chain reaction (PCR), flow cytometry and Western blot analysis showed that TG2 expression was blocked completely when stimulation by either TNF-α or IFN-γ was performed in the presence of nuclear factor (NF)-κB inhibitors (sulphasalazine and BAY-117082). TG2 was up-regulated substantially by TNF-α and IFN-γ in intestinal mucosa in untreated CD compared with controls. This study shows that IFN-γ, a dominant cytokine in intestinal mucosa in active CD, is the most potent inducer of TG2, and synergism with TNF-α may contribute to exacerbate the pathogenic mechanism of CD. Selective inhibition of signalling pathways may be of therapeutic benefit.
Collapse
Affiliation(s)
- M Bayardo
- Laboratorio de Investigación en el Sistema Inmune, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata Servicio de Gastroenterología, Hospital Interzonal de Agudos José de San Martin, La Plata, Argentina
| | | | | | | | | |
Collapse
|
27
|
Jeitner TM, Battaile K, Cooper AJL. γ-Glutamylamines and neurodegenerative diseases. Amino Acids 2012; 44:129-42. [PMID: 22407484 DOI: 10.1007/s00726-011-1209-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 12/22/2011] [Indexed: 12/12/2022]
Abstract
Transglutaminases catalyze the formation of γ-glutamylamines utilizing glutamyl residues and amine-bearing compounds such as lysyl residues and polyamines. These γ-glutamylamines can be released from proteins by proteases in an intact form. The free γ-glutamylamines can be catabolized to 5-oxo-L-proline and the free amine by γ-glutamylamine cyclotransferase. Free γ-glutamylamines, however, accumulate in the CSF and affected areas of Huntington Disease brain. This observation suggests transglutaminase-derived γ-glutamylamines may play a more significant role in neurodegeneration than previously thought. The following monograph reviews the metabolism of γ-glutamylamines and examines the possibility that these species contribute to neurodegeneration.
Collapse
Affiliation(s)
- Thomas M Jeitner
- Neurosciences, Biomedical Research Core, Winthrop University Hospital, 222 Station Plaza North, Mineola, USA.
| | | | | |
Collapse
|
28
|
Hayashi H, Sakai T. Biological Significance of Local TGF-β Activation in Liver Diseases. Front Physiol 2012; 3:12. [PMID: 22363291 PMCID: PMC3277268 DOI: 10.3389/fphys.2012.00012] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 01/17/2012] [Indexed: 12/20/2022] Open
Abstract
The cytokine transforming growth factor-β (TGF-β) plays a pivotal role in a diverse range of cellular responses, including cell proliferation, apoptosis, differentiation, migration, adhesion, angiogenesis, stimulation of extracellular matrix (ECM) synthesis, and downregulation of ECM degradation. TGF-β and its receptors are ubiquitously expressed by most cell types and tissues in vivo. In intact adult tissues and organs, TGF-β is secreted in a biologically inactive (latent) form associated in a non-covalent complex with the ECM. In response to injury, local latent TGF-β complexes are converted into active TGF-β according to a tissue- and injury type-specific activation mechanism. Such a well and tightly orchestrated regulation in TGF-β activity enables an immediate, highly localized response to type-specific tissue injury. In the pathological process of liver fibrosis, TGF-β plays as a master profibrogenic cytokine in promoting activation and myofibroblastic differentiation of hepatic stellate cells, a central event in liver fibrogenesis. Continuous and/or persistent TGF-β signaling induces sustained production of ECM components and of tissue inhibitor of metalloproteinase synthesis. Therefore, the regulation of locally activated TGF-β levels is increasingly recognized as a therapeutic target for liver fibrogenesis. This review summarizes our present knowledge of the activation mechanisms and bioavailability of latent TGF-β in biological and pathological processes in the liver.
Collapse
Affiliation(s)
- Hiromitsu Hayashi
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Cleveland, OH, USA
| | | |
Collapse
|
29
|
|
30
|
Perez Alea M, Thomas V, Martin G, El Alaoui S. Identification of human salivary transglutaminases. Amino Acids 2011; 44:245-50. [PMID: 22080209 DOI: 10.1007/s00726-011-1142-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 10/27/2011] [Indexed: 01/22/2023]
Abstract
Transglutaminases (TGs) expression and enzymatic activities in human saliva were investigated. Specific antibodies showed the co-existence of TG1, TG2, TG3 and TG4. TG2 and TG3 were found in native and multiple proteolytic forms. Our data indicate that TG1 and TG2 isoenzymes are highly active with the major activity attributed to TG1. These findings pave the way for future studies on the physiological role of TG in the oral cavity and the potential impact of their deregulation in TG-associated oral diseases.
Collapse
Affiliation(s)
- Mileidys Perez Alea
- CovalAb, Research Department, 11 Avenue Albert Einstein, 69100 Villeurbanne, Lyon, France.
| | | | | | | |
Collapse
|
31
|
Mithramycin is a gene-selective Sp1 inhibitor that identifies a biological intersection between cancer and neurodegeneration. J Neurosci 2011; 31:6858-70. [PMID: 21543616 DOI: 10.1523/jneurosci.0710-11.2011] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Oncogenic transformation of postmitotic neurons triggers cell death, but the identity of genes critical for degeneration remain unclear. The antitumor antibiotic mithramycin prolongs survival of mouse models of Huntington's disease in vivo and inhibits oxidative stress-induced death in cortical neurons in vitro. We had correlated protection by mithramycin with its ability to bind to GC-rich DNA and globally displace Sp1 family transcription factors. To understand how antitumor drugs prevent neurodegeneration, here we use structure-activity relationships of mithramycin analogs to discover that selective DNA-binding inhibition of the drug is necessary for its neuroprotective effect. We identify several genes (Myc, c-Src, Hif1α, and p21(waf1/cip1)) involved in neoplastic transformation, whose altered expression correlates with protective doses of mithramycin or its analogs. Most interestingly, inhibition of one these genes, Myc, is neuroprotective, whereas forced expression of Myc induces Rattus norvegicus neuronal cell death. These results support a model in which cancer cell transformation shares key genetic components with neurodegeneration.
Collapse
|