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Reed KJ, Landry GM. Diglycolic acid inhibits succinate dehydrogenase activity, depletes mitochondrial membrane potential, and induces inflammation in an SH-SY5Y neuroblastoma model of neurotoxicity in vitro. Toxicol Appl Pharmacol 2023; 463:116414. [PMID: 36754214 DOI: 10.1016/j.taap.2023.116414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/31/2023] [Accepted: 02/01/2023] [Indexed: 02/08/2023]
Abstract
Diethylene glycol is a toxic industrial solvent resulting in a well-defined toxidrome. Diglycolic acid (DGA) has been identified as the metabolite responsible for the nephrotoxicity and hepatotoxicity. These studies assess the mechanism of DGA-induced neurotoxicity, specifically addressing the known ability of DGA to chelate calcium (Ca2+) in solution and inhibit mitochondrial complex II. SH-SY5Y cells were seeded into 96-well plates to assess intracellular Ca2+ chelation, complex II activity, mitochondrial membrane potential (ΔΨm), ATP production, and release of inflammatory cytokines TNF-α and IL-1β with 2-, 4-, 6-, 24-, and 48-h DGA exposure. Peak Ca2+ chelation occurred at 4 h in cells treated with 6.25-50 mM DGA; however, effects were transient. Complex II activity was significantly decreased at all DGA concentrations tested, with 12.5 mM DGA causing 80% inhibition and 25 and 50 mM DGA causing 97 and 100% inhibition, respectively. Subsequently, 12.5-50 mM DGA concentrations significantly decreased ΔΨm at all time points. 50 mM DGA significantly increased release of TNF-α and IL-1β after 24 and 48 h with significantly decreased ATP production observed at the same time points and concentration. These studies demonstrate that the DGA-induced mechanism of SH-SY5Y cell death involves complex II inhibition leading to mitochondrial depolarization, and subsequent ATP depletion with accompanying inflammatory cytokine release. These results indicate a direct mechanism of DGA-induced neurotoxicity in vitro, similarly observed in other DEG-affected target organs.
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Affiliation(s)
- Kristi J Reed
- Massachusetts College of Pharmacy and Health Sciences, School of Pharmacy, Department of Pharmaceutical Sciences, Boston, MA 02115, United States
| | - Greg M Landry
- Massachusetts College of Pharmacy and Health Sciences, School of Pharmacy, Department of Pharmaceutical Sciences, Boston, MA 02115, United States.
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O'Hare Doig RL, Bartlett CA, Smith NM, Hodgetts SI, Dunlop SA, Hool L, Fitzgerald M. Specific combinations of ion channel inhibitors reduce excessive Ca 2+ influx as a consequence of oxidative stress and increase neuronal and glial cell viability in vitro. Neuroscience 2016; 339:450-462. [PMID: 27725216 DOI: 10.1016/j.neuroscience.2016.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 09/15/2016] [Accepted: 10/02/2016] [Indexed: 01/02/2023]
Abstract
Combinations of Ca2+ channel inhibitors have been proposed as an effective means to prevent excess Ca2+ flux and death of neurons and glia following neurotrauma in vivo. However, it is not yet known if beneficial outcomes such as improved viability have been due to direct effects on intracellular Ca2+ concentrations. Here, the effects of combinations of Lomerizine (Lom), 2,3-dioxo-7-(1H-imidazol-1-yl)6-nitro-1,2,3,4-tetrahydro-1-quinoxalinyl]acetic acid monohydrate (YM872), 3,5-dimethyl-1-adamantanamine (memantine (Mem)) and/or adenosine 5'-triphosphate periodate oxidized sodium salt (oxATP) to block voltage-gated Ca2+ channels, Ca2+ permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, NMDA receptors and purinergic P2X7 receptors (P2X7R) respectively, on Ca2+ concentration and viability of rat primary mixed cortical (MC) cultures exposed to hydrogen peroxide (H2O2) insult, were assessed. The contribution of ryanodine-sensitive intracellular stores to intracellular Ca2+ concentration was also assessed. Live cell calcium imaging revealed that a 30min H2O2 insult induced a slow increase in intracellular Ca2+, in part from intracellular sources, associated with loss of cell viability by 6h. Most combinations of inhibitors that included oxATP significantly decreased Ca2+ influx and increased cell viability when administered simultaneously with H2O2. However, reductions in intracellular Ca2+ concentration were not always linked to improved cell viability. Examination of the density of specific cell subpopulations demonstrated that most combinations of inhibitors that included oxATP preserved NG2+ non-oligodendroglial cells, but preservation of astrocytes and neurons required additional inhibitors. Olig2+ oligodendroglia and ED-1+ activated microglia/macrophages were not preserved by any of the inhibitor combinations. These data indicate that following H2O2 insult, limiting intracellular Ca2+ entry via P2X7R is generally associated with increased cell viability. Protection of NG2+ non-oligodendroglial cells by Ca2+ channel inhibitor combinations may contribute to observed beneficial outcomes in vivo.
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Affiliation(s)
- Ryan L O'Hare Doig
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, Western Australia, Australia; School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia; School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Carole A Bartlett
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, Western Australia, Australia; School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Nicole M Smith
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, Western Australia, Australia; School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia; School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia, Australia
| | - Stuart I Hodgetts
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, Western Australia, Australia; School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Sarah A Dunlop
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, Western Australia, Australia; School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Livia Hool
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia; Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
| | - Melinda Fitzgerald
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley, Western Australia, Australia; School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia.
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Liu X, Yao Z. Chronic over-nutrition and dysregulation of GSK3 in diseases. Nutr Metab (Lond) 2016; 13:49. [PMID: 27493677 PMCID: PMC4972972 DOI: 10.1186/s12986-016-0108-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 07/21/2016] [Indexed: 12/16/2022] Open
Abstract
Loss of cellular response to hormonal regulation in maintaining metabolic homeostasis is common in the process of aging. Chronic over-nutrition may render cells insensitive to such a hormonal regulation owing to overstimulation of certain signaling pathways, thus accelerating aging and causing diseases. The glycogen synthase kinase 3 (GSK3) plays a pivotal role in relaying various extracellular and intracellular regulatory signals critical to cell growth, survival, regeneration, or death. The main signaling pathway regulating GSK3 activity through serine-phosphorylation is the phosphoinositide 3-kinase (PI3K)/phosphoinositide-dependent kinase-1 (PDK1)/Akt relay that catalyzes serine-phosphorylation and thus inactivation of GSK3. In addition, perilipin 2 (PLIN2) has recently been shown to regulate GSK3 activation through direct association with GSK3. This review summarizes current understanding on environmental and nutritional factors contributing to GSK3 regulation (or dysregulation) through the PI3K/PDK1/Akt/GSK3 axis, and highlights the newly discovered role that PLIN2 plays in regulating GSK3 activity and GSK3 downstream pathways.
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Affiliation(s)
- Xunxian Liu
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems Biology, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5 Canada
| | - Zemin Yao
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems Biology, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5 Canada
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De Marco G, Lomartire A, Mandili G, Lupino E, Buccinnà B, Ramondetti C, Moglia C, Novelli F, Piccinini M, Mostert M, Rinaudo MT, Chiò A, Calvo A. Reduced cellular Ca(2+) availability enhances TDP-43 cleavage by apoptotic caspases. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:725-34. [PMID: 24440855 DOI: 10.1016/j.bbamcr.2014.01.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 12/20/2013] [Accepted: 01/08/2014] [Indexed: 12/13/2022]
Abstract
Accumulation of transactive response DNA binding protein (TDP-43) fragments in motor neurons is a post mortem hallmark of different neurodegenerative diseases. TDP-43 fragments are the products of the apoptotic caspases-3 and -7. Either excessive or insufficient cellular Ca(2+) availability is associated with activation of apoptotic caspases. However, as far as we know, it is not described whether activation of caspases, due to restricted intracellular Ca(2+), affects TDP-43 cleavage. Here we show that in various cell lineages with restricted Ca(2+) availability, TDP-43 is initially cleaved by caspases-3 and -7 and then, also by caspases-6 and -8 once activated by caspase-3. Furthermore, we disclose the existence of a TDP-43 caspase-mediated fragment of 15kDa, in addition to the well-known fragments of 35 and 25kDa. Interestingly, with respect to the other two fragments this novel fragment is the major product of caspase activity on murine TDP-43 whereas in human cell lines the opposite occurs. This outcome should be considered when murine models are used to investigate TDP-43 proteinopathies.
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Affiliation(s)
- Giovanni De Marco
- 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy; Department of Oncology, University of Turin, Turin, Italy
| | - Annarosa Lomartire
- 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy; Department of Oncology, University of Turin, Turin, Italy
| | - Giorgia Mandili
- Center for Experimental Research and Medical Studies (CeRMS), University of Turin, Turin, Italy; Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin, Italy
| | - Elisa Lupino
- Department of Oncology, University of Turin, Turin, Italy
| | | | | | - Cristina Moglia
- 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy; CRESLA Turin, AOU Città della Salute e della Scienza, Turin, Italy
| | - Francesco Novelli
- Center for Experimental Research and Medical Studies (CeRMS), University of Turin, Turin, Italy; Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin, Italy
| | | | - Michael Mostert
- Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy
| | | | - Adriano Chiò
- 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy; CRESLA Turin, AOU Città della Salute e della Scienza, Turin, Italy
| | - Andrea Calvo
- 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy; CRESLA Turin, AOU Città della Salute e della Scienza, Turin, Italy
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A screen for regulators of survival of motor neuron protein levels. Nat Chem Biol 2011; 7:544-52. [PMID: 21685895 DOI: 10.1038/nchembio.595] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 04/15/2011] [Indexed: 01/15/2023]
Abstract
The motor neuron disease spinal muscular atrophy (SMA) results from mutations that lead to low levels of the ubiquitously expressed protein survival of motor neuron (SMN). An ever-increasing collection of data suggests that therapeutics that elevate SMN may be effective in treating SMA. We executed an image-based screen of annotated chemical libraries and discovered several classes of compounds that were able to increase cellular SMN. Among the most important was the RTK-PI3K-AKT-GSK-3 signaling cascade. Chemical inhibitors of glycogen synthase kinase 3 (GSK-3) and short hairpin RNAs (shRNAs) directed against this target elevated SMN levels primarily by stabilizing the protein. It was particularly notable that GSK-3 chemical inhibitors were also effective in motor neurons, not only in elevating SMN levels, but also in blocking the death that was produced when SMN was acutely reduced by an SMN-specific shRNA. Thus, we have established a screen capable of detecting drug-like compounds that correct the main phenotypic change underlying SMA.
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Padilla A, Descorbeth M, Almeyda AL, Payne K, De Leon M. Hyperglycemia magnifies Schwann cell dysfunction and cell death triggered by PA-induced lipotoxicity. Brain Res 2010; 1370:64-79. [PMID: 21108938 DOI: 10.1016/j.brainres.2010.11.013] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 11/01/2010] [Accepted: 11/05/2010] [Indexed: 01/01/2023]
Abstract
Lipid overload resulting in lipotoxicity is prominent in a number of chronic diseases and has been associated with cellular dysfunction and cell death. This study characterizes palmitic acid-induced lipotoxicity (PA-LTx) in Schwann cell cultures grown in normal and high glucose concentrations. The study shows for the first time that Schwann cell (SC) cultures exposed to elevated levels of PA exhibit a dose- and time-dependent loss in cell viability. Hoescht and Annexin V/7AAD staining confirmed cell death through apoptosis and the lipotoxic effect was more dramatic in SC cultures grown under high glucose conditions. The first indication of cellular dysfunction in treated SC cultures was a decrease in Ca(++) levels in the endoplasmic reticulum (ER, [Ca(++)](ER)) observed five minutes following the initial challenge with PA. This decrease in [Ca(++) ](ER) was followed by a significant increase in the expression of ER stress signature genes CHOP, Xbp1 and GRP78. The early ER stress response induced by PA-LTx was followed by a strong mitochondrial membrane depolarization. Flow cytometry using 2', 7'-dichlorodihydrofluorescein diacetate (H(2)DCFDA) showed an increase in oxidative stress within three to six hours after PA treatment. Treatment of cultures undergoing PA-LTx with the calcium chelator BAPTA-AM and the anti-oxidant MCI-186 significantly reversed the lipotoxic effect by decreasing the generation of ROS and significantly increasing cell viability. We conclude that lipotoxicity in Schwann cells results in cellular dysfunction and cell death that involves a robust ER stress response, mitochondrial dysfunction and an augmented state of cellular oxidative stress (ASCOS).
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Affiliation(s)
- Amelia Padilla
- Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
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Segregation of myoblast fusion and muscle-specific gene expression by distinct ligand-dependent inactivation of GSK-3β. Cell Mol Life Sci 2010; 68:523-35. [PMID: 20694829 PMCID: PMC3021259 DOI: 10.1007/s00018-010-0467-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 07/07/2010] [Accepted: 07/12/2010] [Indexed: 11/16/2022]
Abstract
Myogenic differentiation involves myoblast fusion and induction of muscle-specific gene expression, which are both stimulated by pharmacological (LiCl), genetic, or IGF-I-mediated GSK-3β inactivation. To assess whether stimulation of myogenic differentiation is common to ligand-mediated GSK-3β inactivation, myoblast fusion and muscle-specific gene expression were investigated in response to Wnt-3a. Moreover, crosstalk between IGF-I/GSK-3β/NFATc3 and Wnt/GSK-3β/β-catenin signaling was assessed. While both Wnt-3a and LiCl promoted myoblast fusion, muscle-specific gene expression was increased by LiCl, but not by Wnt-3a or β-catenin over-expression. Furthermore, LiCl and IGF-I, but not Wnt-3a, increased NFATc3 transcriptional activity. In contrast, β-catenin-dependent transcriptional activity was increased by Wnt-3a and LiCl, but not IGF-I. These results for the first time reveal a segregated regulation of myoblast fusion and muscle-specific gene expression following stimulation of myogenic differentiation in response to distinct ligand-specific signaling routes of GSK-3β inactivation.
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