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Teixeira J, Basit F, Willems PHGM, Wagenaars JA, van de Westerlo E, Amorim R, Cagide F, Benfeito S, Oliveira C, Borges F, Oliveira PJ, Koopman WJH. Mitochondria-targeted phenolic antioxidants induce ROS-protective pathways in primary human skin fibroblasts. Free Radic Biol Med 2021; 163:314-324. [PMID: 33359686 DOI: 10.1016/j.freeradbiomed.2020.12.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/10/2020] [Accepted: 12/11/2020] [Indexed: 02/07/2023]
Abstract
Phytochemical antioxidants like gallic and caffeic acid are constituents of the normal human diet that display beneficial health effects, potentially via activating stress response pathways. Using primary human skin fibroblasts (PHSFs) as a model, we here investigated whether such pathways were induced by novel mitochondria-targeted variants of gallic acid (AntiOxBEN2) and caffeic acid (AntiOxCIN4). Both molecules reduced cell viability with similar kinetics and potency (72 h incubation, IC50 ~23 μM). At a relatively high but non-toxic concentration (12.5 μM), AntiOxBEN2 and AntiOxCIN4 increased ROS levels (at 24 h), followed by a decline (at 72 h). Further analysis at the 72 h timepoint demonstrated that AntiOxBEN2 and AntiOxCIN4 did not alter mitochondrial membrane potential (Δψ), but increased cellular glutathione (GSH) levels, mitochondrial NAD(P)H autofluorescence, and mitochondrial superoxide dismutase 2 (SOD2) protein levels. In contrast, cytosolic SOD1 protein levels were not affected. AntiOxBEN2 and AntiOxCIN4 both stimulated the gene expression of Nuclear factor erythroid 2-related factor 2 (NRF2; a master regulator of the cellular antioxidant response toward oxidative stress). AntiOxBEN2 and ANtiOxCIN4 differentially affected the gene expression of the antioxidants Heme oxygenase 1 (HMOX1) and NAD(P)H dehydrogenase (quinone) 1 (NQO1). Both antioxidants did not protect from cell death induced by GSH depletion and AntiOxBEN2 (but not AntiOxCIN4) antagonized hydrogen peroxide-induced cell death. We conclude that AntiOxBEN2 and AntiOxCIN4 increase ROS levels, which stimulates NRF2 expression and, as a consequence, SOD2 and GSH levels. This highlights that AntiOxBEN2 and AntiOxCIN4 can act as prooxidants thereby activating endogenous ROS-protective pathways.
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Affiliation(s)
- José Teixeira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, 3060-197, Cantanhede, Portugal; CIQUP/Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto (UP), 4169-007, Porto, Portugal; Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500HB Nijmegen, the Netherlands.
| | - Farhan Basit
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500HB Nijmegen, the Netherlands
| | - Peter H G M Willems
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500HB Nijmegen, the Netherlands
| | - Jori A Wagenaars
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500HB Nijmegen, the Netherlands
| | - Els van de Westerlo
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500HB Nijmegen, the Netherlands
| | - Ricardo Amorim
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, 3060-197, Cantanhede, Portugal; CIQUP/Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto (UP), 4169-007, Porto, Portugal
| | - Fernando Cagide
- CIQUP/Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto (UP), 4169-007, Porto, Portugal
| | - Sofia Benfeito
- CIQUP/Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto (UP), 4169-007, Porto, Portugal
| | - Catarina Oliveira
- CIQUP/Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto (UP), 4169-007, Porto, Portugal
| | - Fernanda Borges
- CIQUP/Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto (UP), 4169-007, Porto, Portugal
| | - Paulo J Oliveira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, 3060-197, Cantanhede, Portugal
| | - Werner J H Koopman
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500HB Nijmegen, the Netherlands.
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Grefte S, Koopman WJH. Live-Cell Assessment of Reactive Oxygen Species Levels Using Dihydroethidine. Methods Mol Biol 2021; 2275:291-299. [PMID: 34118045 DOI: 10.1007/978-1-0716-1262-0_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Reactive oxygen species (ROS) play an important role in cellular (patho)physiology. Empirical evidence suggests that mitochondria are an important source of ROS, especially under pathological conditions. Here, we describe a method for ROS measurement using dihydroethidium (HEt) and live-cell microscopy.
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Affiliation(s)
- Sander Grefte
- Human and Animal Physiology, Wageningen University & Research, Wageningen, Netherlands
| | - Werner J H Koopman
- Human and Animal Physiology, Wageningen University & Research, Wageningen, Netherlands.
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, The Netherlands.
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3
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Gutierrez B, Gallardo I, Ruiz L, Alvarez Y, Cachofeiro V, Margolles A, Hernandez M, Nieto ML. Oleanolic acid ameliorates intestinal alterations associated with EAE. J Neuroinflammation 2020; 17:363. [PMID: 33246492 PMCID: PMC7697371 DOI: 10.1186/s12974-020-02042-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 11/19/2020] [Indexed: 12/18/2022] Open
Abstract
Background Multiple sclerosis (MS) is a chronic demyelinating autoimmune disease affecting the CNS. Recent studies have indicated that intestinal alterations play key pathogenic roles in the development of autoimmune diseases, including MS. The triterpene oleanolic acid (OA), due to its anti-inflammatory properties, has shown to beneficially influence the severity of the experimental autoimmune encephalomyelitis (EAE), a preclinical model of MS. We herein investigate EAE-associated gut intestinal dysfunction and the effect of OA treatment. Methods Mice with MOG35–55-induced EAE were treated with OA or vehicle from immunization day and were daily analyzed for clinical deficit. We performed molecular and histological analysis in serum and intestinal tissues to measure oxidative and inflammatory responses. We used Caco-2 and HT29-MTX-E12 cells to elucidate OA in vitro effects. Results We found that OA protected from EAE-induced changes in intestinal permeability and preserved the mucin-containing goblet cells along the intestinal tract. Serum levels of the markers for intestinal barrier damage iFABP and monocyte activation sCD14 were consistently and significantly reduced in OA-treated EAE mice. Beneficial OA effects also included a decrease of pro-inflammatory mediators both in serum and colonic tissue of treated-EAE mice. Moreover, the levels of some immunoregulatory cytokines, the neurotrophic factor GDNF, and the gastrointestinal hormone motilin were preserved in OA-treated EAE mice. Regarding oxidative stress, OA treatment prevented lipid peroxidation and superoxide anion accumulation in intestinal tissue, while inducing the expression of the ROS scavenger Sestrin-3. Furthermore, short-chain fatty acids (SCFA) quantification in the cecal content showed that OA reduced the high iso-valeric acid concentrations detected in EAE-mice. Lastly, using in vitro cell models which mimic the intestinal epithelium, we verified that OA protected against intestinal barrier dysfunction induced by injurious agents produced in both EAE and MS. Conclusion These findings reveal that OA ameliorates the gut dysfunction found in EAE mice. OA normalizes the levels of gut mucosal dysfunction markers, as well as the pro- and anti-inflammatory immune bias during EAE, thus reinforcing the idea that OA is a beneficial compound for treating EAE and suggesting that OA may be an interesting candidate to be explored for the treatment of human MS. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-020-02042-6.
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Affiliation(s)
- Beatriz Gutierrez
- Instituto de Biología y Genética Molecular (IBGM-CSIC/UVa), Valladolid, Spain
| | - Isabel Gallardo
- Instituto de Biología y Genética Molecular (IBGM-CSIC/UVa), Valladolid, Spain
| | - Lorena Ruiz
- Dairy Research Institute of Asturias, Spanish National Research Council (IPLA-CSIC), Paseo Río Linares s/n, Villaviciosa, Asturias, Spain.,MicroHealth Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Asturias, Spain
| | - Yolanda Alvarez
- Instituto de Biología y Genética Molecular (IBGM-CSIC/UVa), Valladolid, Spain
| | - Victoria Cachofeiro
- Departamento de Fisiología, Facultad de Medicina, Universidad Complutense de Madrid and Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Abelardo Margolles
- Dairy Research Institute of Asturias, Spanish National Research Council (IPLA-CSIC), Paseo Río Linares s/n, Villaviciosa, Asturias, Spain.,MicroHealth Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Asturias, Spain
| | - Marita Hernandez
- Instituto de Biología y Genética Molecular (IBGM-CSIC/UVa), Valladolid, Spain
| | - Maria Luisa Nieto
- Instituto de Biología y Genética Molecular (IBGM-CSIC/UVa), Valladolid, Spain.
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Study of Eosinophil Apoptosis Induced by Fasciola hepatica Excretory-Secretory Products. Methods Mol Biol 2020. [PMID: 32399926 DOI: 10.1007/978-1-0716-0475-5_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The excretory-secretory products released by the liver fluke Fasciola hepatica (FhESP) are in close contact with the immune system and have different immunomodulatory effects associated with the parasite virulence. The control of the early immune response is crucial for the establishment of the fluke in the host. Related to this, eosinophils (Eo) are implicated as effector cells in helminthic infections, and the induction of Eo apoptosis has been demonstrated to be a remarkable immunoevasion mechanism induced by the parasite. In this chapter, we describe different techniques to assay Eo apoptosis triggered by FhESP as well as the mechanisms involved in this phenomenon.
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Almomani R, Herkert JC, Posafalvi A, Post JG, Boven LG, van der Zwaag PA, Willems PHGM, van Veen-Hof IH, Verhagen JMA, Wessels MW, Nikkels PGJ, Wintjes LT, van den Berg MP, Sinke RJ, Rodenburg RJ, Niezen-Koning KE, van Tintelen JP, Jongbloed JDH. Homozygous damaging SOD2 variant causes lethal neonatal dilated cardiomyopathy. J Med Genet 2019; 57:23-30. [PMID: 31494578 DOI: 10.1136/jmedgenet-2019-106330] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/22/2019] [Accepted: 07/29/2019] [Indexed: 01/05/2023]
Abstract
BACKGROUND Idiopathic dilated cardiomyopathy (DCM) is recognised to be a heritable disorder, yet clinical genetic testing does not produce a diagnosis in >50% of paediatric patients. Identifying a genetic cause is crucial because this knowledge can affect management options, cardiac surveillance in relatives and reproductive decision-making. In this study, we sought to identify the underlying genetic defect in a patient born to consanguineous parents with rapidly progressive DCM that led to death in early infancy. METHODS AND RESULTS Exome sequencing revealed a potentially pathogenic, homozygous missense variant, c.542G>T, p.(Gly181Val), in SOD2. This gene encodes superoxide dismutase 2 (SOD2) or manganese-superoxide dismutase, a mitochondrial matrix protein that scavenges oxygen radicals produced by oxidation-reduction and electron transport reactions occurring in mitochondria via conversion of superoxide anion (O2 -·) into H2O2. Measurement of hydroethidine oxidation showed a significant increase in O2 -· levels in the patient's skin fibroblasts, as compared with controls, and this was paralleled by reduced catalytic activity of SOD2 in patient fibroblasts and muscle. Lentiviral complementation experiments demonstrated that mitochondrial SOD2 activity could be completely restored on transduction with wild type SOD2. CONCLUSION Our results provide evidence that defective SOD2 may lead to toxic increases in the levels of damaging oxygen radicals in the neonatal heart, which can result in rapidly developing heart failure and death. We propose SOD2 as a novel nuclear-encoded mitochondrial protein involved in severe human neonatal cardiomyopathy, thus expanding the wide range of genetic factors involved in paediatric cardiomyopathies.
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Affiliation(s)
- Rowida Almomani
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Johanna C Herkert
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Anna Posafalvi
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Jan G Post
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ludolf G Boven
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Paul A van der Zwaag
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Peter H G M Willems
- Department of Biochemistry, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ingrid H van Veen-Hof
- Laboratory of Metabolic Diseases, Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Judith M A Verhagen
- Department of Clinical Genetics, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Marja W Wessels
- Department of Clinical Genetics, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Peter G J Nikkels
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Liesbeth T Wintjes
- Department of Paediatrics, Radboud Center for Mitochondrial Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Maarten P van den Berg
- Department of Cardiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Richard J Sinke
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Richard J Rodenburg
- Department of Paediatrics, Radboud Center for Mitochondrial Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Klary E Niezen-Koning
- Laboratory of Metabolic Diseases, Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - J Peter van Tintelen
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jan D H Jongbloed
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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6
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Rescue from galactose-induced death of Leigh Syndrome patient cells by pyruvate and NAD .. Cell Death Dis 2018; 9:1135. [PMID: 30429455 PMCID: PMC6235972 DOI: 10.1038/s41419-018-1179-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 10/11/2018] [Accepted: 10/12/2018] [Indexed: 01/08/2023]
Abstract
Cell models of mitochondrial complex I (CI) deficiency display activation of glycolysis to compensate for the loss in mitochondrial ATP production. This adaptation can mask other relevant deficiency-induced aberrations in cell physiology. Here we investigated the viability, mitochondrial morphofunction, ROS levels and ATP homeostasis of primary skin fibroblasts from Leigh Syndrome (LS) patients with isolated CI deficiency. These cell lines harbored mutations in nuclear DNA (nDNA)-encoded CI genes (NDUFS7, NDUFS8, NDUFV1) and, to prevent glycolysis upregulation, were cultured in a pyruvate-free medium in which glucose was replaced by galactose. Following optimization of the cell culture protocol, LS fibroblasts died in the galactose medium, whereas control cells did not. LS cell death was dose-dependently inhibited by pyruvate, malate, oxaloacetate, α-ketoglutarate, aspartate, and exogenous NAD+ (eNAD), but not by lactate, succinate, α-ketobutyrate, and uridine. Pyruvate and eNAD increased the cellular NAD+ content in galactose-treated LS cells to a different extent and co-incubation studies revealed that pyruvate-induced rescue was not primarily mediated by NAD+. Functionally, in LS cells glucose-by-galactose replacement increased mitochondrial fragmentation and mass, depolarized the mitochondrial membrane potential (Δψ), increased H2DCFDA-oxidizing ROS levels, increased mitochondrial ATP generation, and reduced the total cellular ATP content. These aberrations were differentially rescued by pyruvate and eNAD, supporting the conclusion that these compounds rescue galactose-induced LS cell death via different mechanisms. These findings establish a cell-based strategy for intervention testing and enhance our understanding of CI deficiency pathophysiology.
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de Bont CM, Koopman WJH, Boelens WC, Pruijn GJM. Stimulus-dependent chromatin dynamics, citrullination, calcium signalling and ROS production during NET formation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1621-1629. [PMID: 30327203 DOI: 10.1016/j.bbamcr.2018.08.014] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/26/2018] [Accepted: 08/22/2018] [Indexed: 12/21/2022]
Abstract
Neutrophils can release their chromatin to form neutrophil extracellular traps (NETs), a process known as NETosis. Although NET formation can be induced by various stimuli, recent evidence suggests that these stimuli do so via different mechanisms. Here, we have analysed NET formation induced by lipopolysaccharide (LPS), phorbol 12‑myristate 13‑acetate (PMA) and the calcium (Ca2+) ionophore A23187. Our results show distinct peroxidase and neutrophil elastase activities in both culture supernatant and NETs. Especially stimulation with A23187 led to pronounced peroxidase and elastase release and yielded high peroxidase activity on the resulting NETs. In contrast to LPS and PMA, A23187 did not induce morphological changes of the nuclei. Histone H3 citrullination was more extensively observed upon induction by A23187 and particularly in LPS- and PMA-induced NETs the detection of citrullinated H3 was dependent on the inhibition of neutrophil proteases, which suggests that NET-associated citrullinated histones are readily cleaved by these proteases. With live cell imaging techniques, differences in the rate of plasma membrane permeabilization were observed, not only for the different inducers, but also among individual neutrophils. LPS and PMA, but not A23187, induced early calcium oscillations and the cytosolic calcium concentrations gradually increased upon LPS and PMA stimulation until the plasma membrane ruptured. The levels of reactive oxygen species rose rapidly after PMA stimulation and much later in neutrophils exposed to LPS and A23187. Taken together, the observed molecular and dynamic differences indicate that NET formation induced by LPS, PMA and A23187 proceeds via different pathways.
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Affiliation(s)
- Cynthia M de Bont
- Department of Biomolecular Chemistry, Institute of Molecules and Materials (IMM), Radboud University, Nijmegen, the Netherlands
| | - Werner J H Koopman
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Wilbert C Boelens
- Department of Biomolecular Chemistry, Institute of Molecules and Materials (IMM), Radboud University, Nijmegen, the Netherlands
| | - Ger J M Pruijn
- Department of Biomolecular Chemistry, Institute of Molecules and Materials (IMM), Radboud University, Nijmegen, the Netherlands.
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Zhuo M, Gorgun MF, Englander EW. Neurotoxicity of cytarabine (Ara-C) in dorsal root ganglion neurons originates from impediment of mtDNA synthesis and compromise of mitochondrial function. Free Radic Biol Med 2018; 121:9-19. [PMID: 29698743 PMCID: PMC5971160 DOI: 10.1016/j.freeradbiomed.2018.04.570] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/12/2018] [Accepted: 04/21/2018] [Indexed: 12/18/2022]
Abstract
Peripheral Nervous System (PNS) neurotoxicity caused by cancer drugs hinders attainment of chemotherapy goals. Due to leakiness of the blood nerve barrier, circulating chemotherapeutic drugs reach PNS neurons and adversely affect their function. Chemotherapeutic drugs are designed to target dividing cancer cells and mechanisms underlying their toxicity in postmitotic neurons remain to be fully clarified. The objective of this work was to elucidate progression of events triggered by antimitotic drugs in postmitotic neurons. For proof of mechanism study, we chose cytarabine (ara-C), an antimetabolite used in treatment of hematological cancers. Ara-C is a cytosine analog that terminates DNA synthesis. To investigate how ara-C affects postmitotic neurons, which replicate mitochondrial but not genomic DNA, we adapted a model of Dorsal Root Ganglion (DRG) neurons. We showed that DNA polymerase γ, which is responsible for mtDNA synthesis, is inhibited by ara-C and that sublethal ara-C exposure of DRG neurons leads to reduction in mtDNA content, ROS generation, oxidative mtDNA damage formation, compromised mitochondrial respiration and diminution of NADPH and GSH stores, as well as, activation of the DNA damage response. Hence, it is plausible that in ara-C exposed DRG neurons, ROS amplified by the high mitochondrial content shifts from physiologic to pathologic levels signaling stress to the nucleus. Combined, the findings suggest that ara-C neurotoxicity in DRG neurons originates in mitochondria and that continuous mtDNA synthesis and reliance on oxidative phosphorylation for energy needs sensitize the highly metabolic neurons to injury by mtDNA synthesis terminating cancer drugs.
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Affiliation(s)
- Ming Zhuo
- Division of Neurosurgery, Department of Surgery, University of Texas Medical Branch, Galveston, TX, USA
| | - Murat F Gorgun
- Division of Neurosurgery, Department of Surgery, University of Texas Medical Branch, Galveston, TX, USA
| | - Ella W Englander
- Division of Neurosurgery, Department of Surgery, University of Texas Medical Branch, Galveston, TX, USA.
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Extracellular acidification induces ROS- and mPTP-mediated death in HEK293 cells. Redox Biol 2017; 15:394-404. [PMID: 29331741 PMCID: PMC5767902 DOI: 10.1016/j.redox.2017.12.018] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 12/27/2017] [Accepted: 12/28/2017] [Indexed: 12/20/2022] Open
Abstract
The extracellular pH (pHe) is a key determinant of the cellular (micro)environment and needs to be maintained within strict boundaries to allow normal cell function. Here we used HEK293 cells to study the effects of pHe acidification (24 h), induced by mitochondrial inhibitors (rotenone, antimycin A) and/or extracellular HCl addition. Lowering pHe from 7.2 to 5.8 reduced cell viability by 70% and was paralleled by a decrease in cytosolic pH (pHc), hyperpolarization of the mitochondrial membrane potential (Δψ), increased levels of hydroethidine-oxidizing ROS and stimulation of protein carbonylation. Co-treatment with the antioxidant α-tocopherol, the mitochondrial permeability transition pore (mPTP) desensitizer cyclosporin A and Necrostatin-1, a combined inhibitor of Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) and Indoleamine 2,3-dioxygenase (IDO), prevented acidification-induced cell death. In contrast, the caspase inhibitor zVAD.fmk and the ferroptosis inhibitor Ferrostatin-1 were ineffective. We conclude that extracellular acidification induces necroptotic cell death in HEK293 cells and that the latter involves intracellular acidification, mitochondrial functional impairment, increased ROS levels, mPTP opening and protein carbonylation. These findings suggest that acidosis of the extracellular environment (as observed in mitochondrial disorders, ischemia, acute inflammation and cancer) can induce cell death via a ROS- and mPTP opening-mediated pathogenic mechanism. Extracellular acidification induces mitochondrial dysfunction. Extracellular acidification increases intracellular ROS levels. Extracellular acidification stimulates protein carbonylation. Extracellular acidification induces mPTP opening- and ROS-dependent cell death. Acidosis-induced oxidative stress likely contributes to various pathologies.
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LUCS (Light-Up Cell System), a universal high throughput assay for homeostasis evaluation in live cells. Sci Rep 2017; 7:18069. [PMID: 29273711 PMCID: PMC5741755 DOI: 10.1038/s41598-017-18211-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 12/06/2017] [Indexed: 01/14/2023] Open
Abstract
Observations of fluorescent cyanine dye behavior under illumination at 500 nm lead to a novel concept in cell biology allowing the development of a new live cell assay called LUCS, for Light-Up Cell System, measuring homeostasis in live cells. Optimization of the LUCS process resulted in a standardized, straightforward and high throughput assay with applications in toxicity assessment. The mechanisms of the LUCS process were investigated. Electron Paramagnetic Resonance experiments showed that the singlet oxygen and hydroxyl radical are involved downstream of the light effect, presumably leading to deleterious oxidative stress that massively opens access of the dye to its intracellular target. Reversible modulation of LUCS by both verapamil and proton availability indicated that plasma membrane proton/cation antiporters, possibly of the MATE drug efflux transport family, are involved. A mechanistic model is presented. Our data show that intracellular oxidation can be controlled by tuning light energy, opening applications in regulatory purposes, anti-oxidant research, chemotherapy efficacy and dynamic phototherapy strategies.
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Chan W, Almasieh M, Catrinescu MM, Levin LA. Cobalamin-Associated Superoxide Scavenging in Neuronal Cells Is a Potential Mechanism for Vitamin B 12-Deprivation Optic Neuropathy. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 188:160-172. [PMID: 29037851 DOI: 10.1016/j.ajpath.2017.08.032] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Revised: 07/31/2017] [Accepted: 08/28/2017] [Indexed: 12/16/2022]
Abstract
Chronic deficiency of vitamin B12 is the only nutritional deficiency definitively proved to cause optic neuropathy and loss of vision. The mechanism by which this occurs is unknown. Optic neuropathies are associated with death of retinal ganglion cells (RGCs), neurons that project their axons along the optic nerve to the brain. Injury to RGC axons causes a burst of intracellular superoxide, which then signals RGC apoptosis. Vitamin B12 (cobalamin) was recently shown to be a superoxide scavenger, with a rate constant similar to superoxide dismutase. Given that vitamin B12 deficiency causes an optic neuropathy through unknown mechanisms and that it is a potent superoxide scavenger, we tested whether cobalamin, a vitamin B12 vitamer, would be neuroprotective in vitro and in vivo. We found that cobalamin scavenged superoxide in neuronal cells in vitro treated with the reduction-oxidation cycling agent menadione. In vivo confocal scanning laser ophthalmoscopy demonstrated that optic nerve transection in Long-Evans rats increased superoxide levels in RGCs. The RGC superoxide burst was significantly reduced by intravitreal cobalamin and resulted in increased RGC survival. These data demonstrate that cobalamin may function as an endogenous neuroprotectant for RGCs through a superoxide-associated mechanism.
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Affiliation(s)
- Wesley Chan
- Maisonneuve-Rosemont Hospital Research Center and Department of Ophthalmology, University of Montreal, Montreal, Quebec, Canada
| | - Mohammadali Almasieh
- Maisonneuve-Rosemont Hospital Research Center and Department of Ophthalmology, University of Montreal, Montreal, Quebec, Canada; Department of Ophthalmology, McGill University, Montreal, Quebec, Canada; Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Maria-Magdalena Catrinescu
- Maisonneuve-Rosemont Hospital Research Center and Department of Ophthalmology, University of Montreal, Montreal, Quebec, Canada; Department of Ophthalmology, McGill University, Montreal, Quebec, Canada; Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Leonard A Levin
- Maisonneuve-Rosemont Hospital Research Center and Department of Ophthalmology, University of Montreal, Montreal, Quebec, Canada; Department of Ophthalmology, McGill University, Montreal, Quebec, Canada; Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada; Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
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Cisplatin Toxicity in Dorsal Root Ganglion Neurons Is Relieved by Meclizine via Diminution of Mitochondrial Compromise and Improved Clearance of DNA Damage. Mol Neurobiol 2016; 54:7883-7895. [PMID: 27858292 DOI: 10.1007/s12035-016-0273-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 10/30/2016] [Indexed: 01/09/2023]
Abstract
Chemotherapy-induced neurotoxicity of peripheral nervous system (PNS) hinders efficacy of cancer treatments. Mechanisms initiating PNS injury by anticancer drugs are incompletely understood delaying development of effective management strategies. To understand events triggered in PNS by cancer drugs, we exposed dorsal root ganglion (DRG) neurons to cisplatin, a drug from platinum-based class of chemotherapeutics frequently implicated in peripheral neuropathies. While cisplatin enters cancer cells and forms cisplatin/DNA crosslinks that block cell proliferation, circulating cisplatin can also reach the PNS and produce crosslinks that impede critical DNA transactions in postmitotic neurons. Cisplatin forms crosslinks with both, nuclear and mitochondrial DNA (mtDNA). Crosslinks are repairable primarily via the nucleotide excision repair (NER) pathway, which is present in nuclei but absent from mitochondrial compartment. Hence, high mitochondrial content and limited shielding by blood nerve barrier make DRG neurons particularly vulnerable to mitochondrial injury by cisplatin. We report that in DRG neurons, cisplatin elevates reactive oxygen species, depletes mtDNA, and impairs mitochondrial respiration, whereas concomitant meclizine supplementation preserves redox balance, attenuates mitochondrial compromise, and augments DNA repair. Meclizine is an antihistamine drug recently implicated in neuroprotection via modulation of energy metabolism. Our data demonstrate that in the mitochondria-rich DRG neurons, meclizine mitigates cisplatin-induced mitochondrial compromise via enhancement of pentose phosphate pathway and repletion of nicotinamide adenine dinucleotide phosphate (NADPH) and glutathione stores. The findings suggest that meclizine-mediated preservation of redox balance sustains mitochondrial respiration and supports execution of cellular processes, including timely removal of cisplatin crosslinks from nuclear DNA, thereby attenuating cisplatin toxicity in DRG neurons. Collectively, the findings reveal potential for pharmacologic modulation of dorsal root ganglion neurons metabolism for protection against toxicity of chemotherapeutic drugs.
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Who did the case? Perceptions on resident operative participation. Am J Surg 2016; 213:821-826. [PMID: 27866727 DOI: 10.1016/j.amjsurg.2016.11.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 10/31/2016] [Accepted: 11/04/2016] [Indexed: 11/22/2022]
Abstract
BACKGROUND The ACGME case log is one of the primary metrics used to determine resident competency; it is unclear if this is an accurate reflection of the residents' role and participation. METHODS Residents and faculty were independently administered 16-question surveys following each case over a three-week period. The main outcome was agreement between resident and faculty on resident role and percent of the case performed by the resident. RESULTS Matched responses were collected for 87 cases. Agreement on percent performed occurred in 61% of cases, on role in 63%, and on both in 47%. Disagreement was more often due to resident perception they performed more of the case. Faculty with <10 years experience were more likely to have disagreement compared to faculty with ≥10 years (p = 0.009). CONCLUSIONS There was a high degree of disagreement between faculty and residents regarding percent of the case performed and role. Accurate understanding of participation and competency is vital for accrediting institutions and for resident self-assessment meriting further study of the causes for this disagreement to improve training and evaluation.
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Liemburg-Apers DC, Wagenaars JAL, Smeitink JAM, Willems PHGM, Koopman WJH. Acute stimulation of glucose influx upon mitoenergetic dysfunction requires LKB1, AMPK, Sirt2 and mTOR-RAPTOR. J Cell Sci 2016; 129:4411-4423. [PMID: 27793977 DOI: 10.1242/jcs.194480] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 10/24/2016] [Indexed: 12/20/2022] Open
Abstract
Mitochondria play a central role in cellular energy production, and their dysfunction can trigger a compensatory increase in glycolytic flux to sustain cellular ATP levels. Here, we studied the mechanism of this homeostatic phenomenon in C2C12 myoblasts. Acute (30 min) mitoenergetic dysfunction induced by the mitochondrial inhibitors piericidin A and antimycin A stimulated Glut1-mediated glucose uptake without altering Glut1 (also known as SLC2A1) mRNA or plasma membrane levels. The serine/threonine liver kinase B1 (LKB1; also known as STK11) and AMP-activated protein kinase (AMPK) played a central role in this stimulation. In contrast, ataxia-telangiectasia mutated (ATM; a potential AMPK kinase) and hydroethidium (HEt)-oxidizing reactive oxygen species (ROS; increased in piericidin-A- and antimycin-A-treated cells) appeared not to be involved in the stimulation of glucose uptake. Treatment with mitochondrial inhibitors increased NAD+ and NADH levels (associated with a lower NAD+:NADH ratio) but did not affect the level of Glut1 acetylation. Stimulation of glucose uptake was greatly reduced by chemical inhibition of Sirt2 or mTOR-RAPTOR. We propose that mitochondrial dysfunction triggers LKB1-mediated AMPK activation, which stimulates Sirt2 phosphorylation, leading to activation of mTOR-RAPTOR and Glut1-mediated glucose uptake.
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Affiliation(s)
- Dania C Liemburg-Apers
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500HB, Nijmegen, The Netherlands.,Centre for Systems Biology and Bioenergetics, Radboud University and Radboud University Medical Center, 6500HB, Nijmegen, The Netherlands.,Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, 6525GA, Nijmegen, The Netherlands
| | - Jori A L Wagenaars
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500HB, Nijmegen, The Netherlands.,Centre for Systems Biology and Bioenergetics, Radboud University and Radboud University Medical Center, 6500HB, Nijmegen, The Netherlands.,Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, 6525GA, Nijmegen, The Netherlands
| | - Jan A M Smeitink
- Centre for Systems Biology and Bioenergetics, Radboud University and Radboud University Medical Center, 6500HB, Nijmegen, The Netherlands.,Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, 6525GA, Nijmegen, The Netherlands
| | - Peter H G M Willems
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500HB, Nijmegen, The Netherlands.,Centre for Systems Biology and Bioenergetics, Radboud University and Radboud University Medical Center, 6500HB, Nijmegen, The Netherlands.,Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, 6525GA, Nijmegen, The Netherlands
| | - Werner J H Koopman
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500HB, Nijmegen, The Netherlands .,Centre for Systems Biology and Bioenergetics, Radboud University and Radboud University Medical Center, 6500HB, Nijmegen, The Netherlands.,Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, 6525GA, Nijmegen, The Netherlands
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15
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Zhuo M, Gorgun MF, Englander EW. Augmentation of glycolytic metabolism by meclizine is indispensable for protection of dorsal root ganglion neurons from hypoxia-induced mitochondrial compromise. Free Radic Biol Med 2016; 99:20-31. [PMID: 27458119 PMCID: PMC5538108 DOI: 10.1016/j.freeradbiomed.2016.07.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 07/19/2016] [Accepted: 07/21/2016] [Indexed: 01/12/2023]
Abstract
To meet energy demands, dorsal root ganglion (DRG) neurons harbor high mitochondrial content, which renders them acutely vulnerable to disruptions of energy homeostasis. While neurons typically rely on mitochondrial energy production and have not been associated with metabolic plasticity, new studies reveal that meclizine, a drug, recently linked to modulations of energy metabolism, protects neurons from insults that disrupt energy homeostasis. We show that meclizine rapidly enhances glycolysis in DRG neurons and that glycolytic metabolism is indispensable for meclizine-exerted protection of DRG neurons from hypoxic stress. We report that supplementation of meclizine during hypoxic exposure prevents ATP depletion, preserves NADPH and glutathione stores, curbs reactive oxygen species (ROS) and attenuates mitochondrial clustering in DRG neurites. Using extracellular flux analyzer, we show that in cultured DRG neurons meclizine mitigates hypoxia-induced loss of mitochondrial respiratory capacity. Respiratory capacity is a measure of mitochondrial fitness and cell ability to meet fluctuating energy demands and therefore, a key determinant of cellular fate. While meclizine is an 'old' drug with long record of clinical use, its ability to modulate energy metabolism has been uncovered only recently. Our findings documenting neuroprotection by meclizine in a setting of hypoxic stress reveal previously unappreciated metabolic plasticity of DRG neurons as well as potential for pharmacological harnessing of the newly discovered metabolic plasticity for protection of peripheral nervous system under mitochondria compromising conditions.
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Affiliation(s)
- Ming Zhuo
- Department of Surgery, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
| | - Murat F Gorgun
- Department of Surgery, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
| | - Ella W Englander
- Department of Surgery, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.
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Forkink M, Basit F, Teixeira J, Swarts HG, Koopman WJH, Willems PHGM. Complex I and complex III inhibition specifically increase cytosolic hydrogen peroxide levels without inducing oxidative stress in HEK293 cells. Redox Biol 2015; 6:607-616. [PMID: 26516986 PMCID: PMC4635408 DOI: 10.1016/j.redox.2015.09.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/01/2015] [Accepted: 09/07/2015] [Indexed: 12/17/2022] Open
Abstract
Inhibitor studies with isolated mitochondria demonstrated that complex I (CI) and III (CIII) of the electron transport chain (ETC) can act as relevant sources of mitochondrial reactive oxygen species (ROS). Here we studied ROS generation and oxidative stress induction during chronic (24h) inhibition of CI and CIII using rotenone (ROT) and antimycin A (AA), respectively, in intact HEK293 cells. Both inhibitors stimulated oxidation of the ROS sensor hydroethidine (HEt) and increased mitochondrial NAD(P)H levels without major effects on cell viability. Integrated analysis of cells stably expressing cytosolic- or mitochondria-targeted variants of the reporter molecules HyPer (H2O2-sensitive and pH-sensitive) and SypHer (H2O2-insensitive and pH-sensitive), revealed that CI- and CIII inhibition increased cytosolic but not mitochondrial H2O2 levels. Total and mitochondria-specific lipid peroxidation was not increased in the inhibited cells as reported by the C11-BODIPY(581/591) and MitoPerOx biosensors. Also expression of the superoxide-detoxifying enzymes CuZnSOD (cytosolic) and MnSOD (mitochondrial) was not affected. Oxyblot analysis revealed that protein carbonylation was not stimulated by CI and CIII inhibition. Our findings suggest that chronic inhibition of CI and CIII: (i) increases the levels of HEt-oxidizing ROS and (ii) specifically elevates cytosolic but not mitochondrial H2O2 levels, (iii) does not induce oxidative stress or substantial cell death. We conclude that the increased ROS levels are below the stress-inducing level and might play a role in redox signaling.
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Affiliation(s)
- Marleen Forkink
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Farhan Basit
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - José Teixeira
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands; CIQUP/Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Portugal
| | - Herman G Swarts
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Werner J H Koopman
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands.
| | - Peter H G M Willems
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
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