Publications by authors named "Pier G Mastroberardino"

33 Publications

PML-controlled responses in severe congenital neutropenia with ELANE-misfolding mutations.

Blood Adv 2021 Feb;5(3):775-786

Department of Hematology.

Mutations in ELANE cause severe congenital neutropenia (SCN), but how they affect neutrophil production and contribute to leukemia predisposition is unknown. Neutropenia is alleviated by CSF3 (granulocyte colony-stimulating factor) therapy in most cases, but dose requirements vary between patients. Here, we show that CD34+CD45+ hematopoietic progenitor cells (HPCs) derived from induced pluripotent stem cell lines from patients with SCN that have mutations in ELANE (n = 2) or HAX1 (n = 1) display elevated levels of reactive oxygen species (ROS) relative to normal iPSC-derived HPCs. In patients with ELANE mutations causing misfolding of the neutrophil elastase (NE) protein, HPCs contained elevated numbers of promyelocyte leukemia protein nuclear bodies, a hallmark of acute oxidative stress. This was confirmed in primary bone marrow cells from 3 additional patients with ELANE-mutant SCN. Apart from responding to elevated ROS levels, PML controlled the metabolic state of these ELANE-mutant HPCs as well as the expression of ELANE, suggestive of a feed-forward mechanism of disease development. Both PML deletion and correction of the ELANE mutation restored CSF3 responses of these ELANE-mutant HPCs. These findings suggest that PML plays a crucial role in the disease course of ELANE-SCN characterized by NE misfolding, with potential implications for CSF3 therapy.
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http://dx.doi.org/10.1182/bloodadvances.2020003214DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7876869PMC
February 2021

Gender biased neuroprotective effect of Transferrin Receptor 2 deletion in multiple models of Parkinson's disease.

Cell Death Differ 2020 Dec 16. Epub 2020 Dec 16.

Department of Molecular Genetics, Rotterdam, the Netherlands.

Alterations in the metabolism of iron and its accumulation in the substantia nigra pars compacta accompany the pathogenesis of Parkinson's disease (PD). Changes in iron homeostasis also occur during aging, which constitutes a PD major risk factor. As such, mitigation of iron overload via chelation strategies has been considered a plausible disease modifying approach. Iron chelation, however, is imperfect because of general undesired side effects and lack of specificity; more effective approaches would rely on targeting distinctive pathways responsible for iron overload in brain regions relevant to PD and, in particular, the substantia nigra. We have previously demonstrated that the Transferrin/Transferrin Receptor 2 (TfR2) iron import mechanism functions in nigral dopaminergic neurons, is perturbed in PD models and patients, and therefore constitutes a potential therapeutic target to halt iron accumulation. To validate this hypothesis, we generated mice with targeted deletion of TfR2 in dopaminergic neurons. In these animals, we modeled PD with multiple approaches, based either on neurotoxin exposure or alpha-synuclein proteotoxic mechanisms. We found that TfR2 deletion can provide neuroprotection against dopaminergic degeneration, and against PD- and aging-related iron overload. The effects, however, were significantly more pronounced in females rather than in males. Our data indicate that the TfR2 iron import pathway represents an amenable strategy to hamper PD progression. Data also suggest, however, that therapeutic strategies targeting TfR2 should consider a potential sexual dimorphism in neuroprotective response.
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http://dx.doi.org/10.1038/s41418-020-00698-4DOI Listing
December 2020

The Coming of Age for Big Data in Systems Radiobiology, an Engineering Perspective.

Big Data 2021 Feb 29;9(1):63-71. Epub 2020 Sep 29.

School of Informatics, Aristotle University of Thessalonica (AUTH), Thessalonica, Greece.

As high-throughput approaches in biological and biomedical research are transforming the life sciences into information-driven disciplines, modern analytics platforms for big data have started to address the needs for efficient and systematic data analysis and interpretation. We observe that radiobiology is following this general trend, with -omics information providing unparalleled depth into the biomolecular mechanisms of radiation response-defined as systems radiobiology. We outline the design of computational frameworks and discuss the analysis of big data in low-dose ionizing radiation (LDIR) responses of the mammalian brain. Following successful examples and best practices of approaches for the analysis of big data in life sciences and health care, we present the needs and requirements for radiation research. Our goal is to raise awareness for the radiobiology community about the new technological possibilities that can capture complex information and execute data analytics on a large scale. The production of large data sets from genome-wide experiments (quantity) and the complexity of radiation research with multidimensional experimental designs (quality) will necessitate the adoption of latest information technologies. The main objective was to translate research results into applied clinical and epidemiological practice and understand the responses of biological tissues to LDIR to define new radiation protection policies. We envisage a future where multidisciplinary teams include data scientists, artificial intelligence experts, DevOps engineers, and of course radiation experts to fulfill the augmented needs of the radiobiology community, accelerate research, and devise new strategies.
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http://dx.doi.org/10.1089/big.2019.0144DOI Listing
February 2021

A perspective on DNA damage-induced potentiation of the pentose phosphate shunt and reductive stress in chemoresistance.

Mol Cell Oncol 2020 22;7(3):1733383. Epub 2020 Mar 22.

Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, Netherlands.

Metabolic rearrangements and genome instability are two hallmarks of cancer. Recent evidence from our laboratory demonstrates that persistent DNA lesions hampering transcription may cause glucose rerouting through the pentose phosphate shunt and reductive stress. Here, we highlight the relevance of these findings for cancer and chemoresistance development.
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http://dx.doi.org/10.1080/23723556.2020.1733383DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7199736PMC
March 2020

DNA damage and transcription stress cause ATP-mediated redesign of metabolism and potentiation of anti-oxidant buffering.

Nat Commun 2019 10 25;10(1):4887. Epub 2019 Oct 25.

Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, the Netherlands.

Accumulation of DNA lesions causing transcription stress is associated with natural and accelerated aging and culminates with profound metabolic alterations. Our understanding of the mechanisms governing metabolic redesign upon genomic instability, however, is highly rudimentary. Using Ercc1-defective mice and Xpg knock-out mice, we demonstrate that combined defects in transcription-coupled DNA repair (TCR) and in nucleotide excision repair (NER) directly affect bioenergetics due to declined transcription, leading to increased ATP levels. This in turn inhibits glycolysis allosterically and favors glucose rerouting through the pentose phosphate shunt, eventually enhancing production of NADPH-reducing equivalents. In NER/TCR-defective mutants, augmented NADPH is not counterbalanced by increased production of pro-oxidants and thus pentose phosphate potentiation culminates in an over-reduced redox state. Skin fibroblasts from the TCR disease Cockayne syndrome confirm results in animal models. Overall, these findings unravel a mechanism connecting DNA damage and transcriptional stress to metabolic redesign and protective antioxidant defenses.
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http://dx.doi.org/10.1038/s41467-019-12640-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6814737PMC
October 2019

Peripheral mitochondrial function correlates with clinical severity in idiopathic Parkinson's disease.

Mov Disord 2019 08 28;34(8):1192-1202. Epub 2019 May 28.

Department of Molecular Genetics, Erasmus Medical Center, Rotterdam, The Netherlands.

Background: Parkinson's disease is an intractable disorder with heterogeneous clinical presentation that may reflect different underlying pathogenic mechanisms. Surrogate indicators of pathogenic processes correlating with clinical measures may assist in better patient stratification. Mitochondrial function, which is impaired in and central to PD pathogenesis, may represent one such surrogate indicator.

Methods: Mitochondrial function was assessed by respirometry experiment in fibroblasts derived from idiopathic patients (n = 47) in normal conditions and in experimental settings that do not permit glycolysis and therefore force energy production through mitochondrial function. Respiratory parameters and clinical measures were correlated with bivariate analysis. Machine-learning-based classification and regression trees were used to classify patients on the basis of biochemical and clinical measures. The effects of mitochondrial respiration on α-synuclein stress were assessed monitoring the protein phosphorylation in permitting versus restrictive glycolysis conditions.

Results: Bioenergetic properties in peripheral fibroblasts correlate with clinical measures in idiopathic patients, and the correlation is stronger with predominantly nondopaminergic signs. Bioenergetic analysis under metabolic stress, in which energy is produced solely by mitochondria, shows that patients' fibroblasts can augment respiration, therefore indicating that mitochondrial defects are reversible. Forcing energy production through mitochondria, however, favors α-synuclein stress in different cellular experimental systems. Machine-learning-based classification identified different groups of patients in which increasing disease severity parallels higher mitochondrial respiration.

Conclusion: The suppression of mitochondrial activity in PD may be an adaptive strategy to cope with concomitant pathogenic factors. Moreover, mitochondrial measures in fibroblasts are potential peripheral biomarkers to follow disease progression. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.
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http://dx.doi.org/10.1002/mds.27723DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6771759PMC
August 2019

Endocytic iron trafficking and mitochondria in Parkinson's disease.

Int J Biochem Cell Biol 2019 05 25;110:70-74. Epub 2019 Feb 25.

Department of Molecular Genetics, Erasmus University Medical Center Rotterdam, the Netherlands; Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy. Electronic address:

Parkinson's disease (PD) - the second most common neurodegenerative disorder - is a multifactorial disease, the causes of which should be sought in complex and detrimental interactions between genetic and environmental factors. Multiple lines of evidence, however, identify mitochondrial dysfunction, oxidative stress, and iron accumulation as central pathogenic mechanisms. These factors are closely intertwined because mitochondria are a major source of pro-oxidant species and are the major intracellular recipients of iron. How iron is transported to mitochondria, however, is largely unknown. Some studies suggest that trafficking through endocytosis may participate to mitochondrial iron delivery with a "kiss and run" mechanism. Intracellular transferrin levels increase in PD, possibly as a consequence of oxidation of iron-containing prosthetic groups in mitochondria. It is therefore conceivable that transferrin endocytic trafficking can contribute to noxious iron accumulation. This short review will summarize these findings and discuss their relevance for a better understanding of PD pathogenesis.
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http://dx.doi.org/10.1016/j.biocel.2019.02.009DOI Listing
May 2019

Metabolic Alterations in Aging Macrophages: Ingredients for Inflammaging?

Trends Immunol 2019 02 6;40(2):113-127. Epub 2019 Jan 6.

Department of Immunology, Erasmus University Medical Center, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands. Electronic address:

Aging is a complex process with an impact on essentially all organs. Declined cellular repair causes increased damage at genomic and proteomic levels upon aging. This can lead to systemic changes in metabolism and pro-inflammatory cytokine production, resulting in low-grade inflammation, or 'inflammaging'. Tissue macrophages, gatekeepers of parenchymal homeostasis and integrity, are prime inflammatory cytokine producers, as well as initiators and regulators of inflammation. In this opinion piece, we summarize intrinsic alterations in macrophage phenotype and function with age. We propose that alternatively activated macrophages (M2-like), which are yet pro-inflammatory, can accumulate in tissues and promote inflammaging. Age-related increases in endoplasmic reticulum stress and mitochondrial dysfunction might be cell-intrinsic forces driving this unusual phenotype.
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http://dx.doi.org/10.1016/j.it.2018.12.007DOI Listing
February 2019

Bioenergetics in fibroblasts of patients with Huntington disease are associated with age at onset.

Neurol Genet 2018 Oct 4;4(5):e275. Epub 2018 Oct 4.

Department of Neurology (S.L.G., M.H., R.A.C.R., N.A.A.), Department of Human Genetic (S.L.G., R.A.M.B., W.M.C.v.R.-M.), and Department of Clinical Genetics (M.W.B.), Leiden University Medical Centre, Leiden; Department of Molecular Genetics (C.M., P.G.M.), Erasmus Medical Centre, Rotterdam, The Netherlands; and German Center for Neurodegenerative Diseases (DZNE) (N.A.A.), Bonn, Germany.

Objective: We aimed to assess whether differences in energy metabolism in fibroblast cell lines derived from patients with Huntington disease were associated with age at onset independent of the cytosine-adenine-guanine (CAG) repeat number in the mutant allele.

Methods: For this study, we selected 9 pairs of patients with Huntington disease matched for mutant CAG repeat size and sex, but with a difference of at least 10 years in age at onset, using the Leiden Huntington disease database. From skin biopsies, we isolated fibroblasts in which we (1) quantified the ATP concentration before and after a hydrogen-peroxide challenge and (2) measured mitochondrial respiration and glycolysis in real time, using the Seahorse XF Extracellular Flux Analyzer XF24.

Results: The ATP concentration in fibroblasts was significantly lower in patients with Huntington disease with an earlier age at onset, independent of calendar age and disease duration. Maximal respiration, spare capacity, and respiration dependent on complex II activity, and indices of mitochondrial respiration were significantly lower in patients with Huntington disease with an earlier age at onset, again independent of calendar age and disease duration.

Conclusions: A less efficient bioenergetics profile was found in fibroblast cells from patients with Huntington disease with an earlier age at onset independent of mutant CAG repeat size. Thus, differences in bioenergetics could explain part of the residual variation in age at onset in Huntington disease.
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http://dx.doi.org/10.1212/NXG.0000000000000275DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6186024PMC
October 2018

Activation of the DNA damage response in vivo in synucleinopathy models of Parkinson's disease.

Cell Death Dis 2018 07 26;9(8):818. Epub 2018 Jul 26.

Department of Molecular Genetics, Rotterdam, The Netherlands.

The involvement of DNA damage and repair in aging processes is well established. Aging is an unequivocal risk factor for chronic neurodegenerative diseases, underscoring the relevance of investigations into the role that DNA alterations may have in the pathogenesis of these diseases. Consistently, even moderate impairment of DNA repair systems facilitates the onset of pathological features typical of PD that include derangement of the dopaminergic system, mitochondrial dysfunction, and alpha-synuclein stress. The latter establishes a connection between reduced DNA repair capacity and a cardinal feature of PD, alpha-synuclein pathology. It remains to be determined, however, whether alpha-synuclein stress activates in vivo the canonical signaling cascade associated with DNA damage, which is centered on the kinase ATM and substrates such as γH2Ax and 53BP1. Addressing these issues would shed light on age-related mechanisms impinging upon PD pathogenesis and neurodegeneration in particular. We analyzed two different synucleinopathy PD mouse models based either on intranigral delivery of AAV-expressing human alpha-synuclein, or intrastriatal injection of human alpha-synuclein pre-formed fibrils. In both cases, we detected a significant increase in γH2AX and 53BP1 foci, and in phospho-ATM immunoreactivity in dopaminergic neurons, which collectively indicate DNA damage and activation of the DNA damage response. Mechanistic experiments in cell cultures indicate that activation of the DNA damage response is caused, at least in part, by pro-oxidant species because it is prevented by exogenous or endogenous antioxidants, which also rescue mitochondrial anomalies caused by proteotoxic alpha-synuclein. These in vivo and in vitro findings reveal that the cellular stress mediated by alpha-synuclein-a pathological hallmark in PD-elicits DNA damage and activates the DNA damage response. The toxic cascade leading to DNA damage involves oxidant stress and mitochondrial dysfunction The data underscore the importance of DNA quality control for preservation of neuronal integrity and protection against neurodegenerative processes.
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http://dx.doi.org/10.1038/s41419-018-0848-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6062587PMC
July 2018

Decreased mitochondrial respiration in aneurysmal aortas of Fibulin-4 mutant mice is linked to PGC1A regulation.

Cardiovasc Res 2018 11;114(13):1776-1793

Department of Vascular Surgery, Erasmus MC, Wytemaweg 80, CN Rotterdam, The Netherlands.

Aim: Thoracic aortic aneurysms are a life-threatening condition often diagnosed too late. To discover novel robust biomarkers, we aimed to better understand the molecular mechanisms underlying aneurysm formation.

Methods And Results: In Fibulin-4R/R mice, the extracellular matrix protein Fibulin-4 is 4-fold reduced, resulting in progressive ascending aneurysm formation and early death around 3 months of age. We performed proteomics and genomics studies on Fibulin-4R/R mouse aortas. Intriguingly, we observed alterations in mitochondrial protein composition in Fibulin-4R/R aortas. Consistently, functional studies in Fibulin-4R/R vascular smooth muscle cells (VSMCs) revealed lower oxygen consumption rates, but increased acidification rates. Yet, mitochondria in Fibulin-4R/R VSMCs showed no aberrant cytoplasmic localization. We found similar reduced mitochondrial respiration in Tgfbr-1M318R/+ VSMCs, a mouse model for Loeys-Dietz syndrome (LDS). Interestingly, also human fibroblasts from Marfan (FBN1) and LDS (TGFBR2 and SMAD3) patients showed lower oxygen consumption. While individual mitochondrial Complexes I-V activities were unaltered in Fibulin-4R/R heart and muscle, these tissues showed similar decreased oxygen consumption. Furthermore, aortas of aneurysmal Fibulin-4R/R mice displayed increased reactive oxygen species (ROS) levels. Consistent with these findings, gene expression analyses revealed dysregulation of metabolic pathways. Accordingly, blood ketone levels of Fibulin-4R/R mice were reduced and liver fatty acids were decreased, while liver glycogen was increased, indicating dysregulated metabolism at the organismal level. As predicted by gene expression analysis, the activity of PGC1α, a key regulator between mitochondrial function and organismal metabolism, was downregulated in Fibulin-4R/R VSMCs. Increased TGFβ reduced PGC1α levels, indicating involvement of TGFβ signalling in PGC1α regulation. Activation of PGC1α restored the decreased oxygen consumption in Fibulin-4R/R VSMCs and improved their reduced growth potential, emphasizing the importance of this key regulator.

Conclusion: Our data indicate altered mitochondrial function and metabolic dysregulation, leading to increased ROS levels and altered energy production, as a novel mechanism, which may contribute to thoracic aortic aneurysm formation.
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http://dx.doi.org/10.1093/cvr/cvy150DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6198735PMC
November 2018

Mitochondrial Complex I Reversible S-Nitrosation Improves Bioenergetics and Is Protective in Parkinson's Disease.

Antioxid Redox Signal 2018 Jan 21;28(1):44-61. Epub 2017 Sep 21.

1 Department of Molecular Genetics, Erasmus MC , Rotterdam, The Netherlands .

Aims: This study was designed to explore the neuroprotective potential of inorganic nitrite as a new therapeutic avenue in Parkinson's disease (PD).

Results: Administration of inorganic nitrite ameliorates neuropathology in phylogenetically distinct animal models of PD. Beneficial effects are not confined to prophylactic treatment and also occur if nitrite is administered when the pathogenic cascade is already active. Mechanistically, the effect is mediated by both complex I S-nitrosation, which under nitrite administration is favored over formation of other forms of oxidation, and down-stream activation of the antioxidant Nrf2 pathway. Nitrite also rescues respiratory reserve capacity and increases proton leakage in LRRK2 PD patients' dermal fibroblasts.

Innovation: The study proposes an unprecedented approach based on the administration of the nitrosonium donor nitrite to contrast complex I and redox anomalies in PD. Dysfunctional mitochondrial complex I propagates oxidative stress in PD, and treatments mitigating this defect may, therefore, limit disease progression. Therapeutic complex I targeting has been successfully achieved in ischemia/reperfusion by using nitrosonium donors such as nitrite to reversibly modify its subunits and protect from oxidative damage after reperfusion. This evidence led to the innovative hypothesis that nitrite could exert protective effects also in pathological conditions where complex I dysfunction occurs in normoxia, such as in PD.

Conclusions: Overall, these results demonstrate that administration of inorganic nitrite improves mitochondrial function in PD, and it, therefore, represents an amenable intervention to hamper disease progression. Antioxid. Redox Signal. 28, 44-61.
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http://dx.doi.org/10.1089/ars.2017.6992DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5749586PMC
January 2018

Mesenchymal Inflammation Drives Genotoxic Stress in Hematopoietic Stem Cells and Predicts Disease Evolution in Human Pre-leukemia.

Cell Stem Cell 2016 11 22;19(5):613-627. Epub 2016 Sep 22.

Department of Hematology, Erasmus MC Cancer Institute, Rotterdam 3015CN, the Netherlands. Electronic address:

Mesenchymal niche cells may drive tissue failure and malignant transformation in the hematopoietic system, but the underlying molecular mechanisms and relevance to human disease remain poorly defined. Here, we show that perturbation of mesenchymal cells in a mouse model of the pre-leukemic disorder Shwachman-Diamond syndrome (SDS) induces mitochondrial dysfunction, oxidative stress, and activation of DNA damage responses in hematopoietic stem and progenitor cells. Massive parallel RNA sequencing of highly purified mesenchymal cells in the SDS mouse model and a range of human pre-leukemic syndromes identified p53-S100A8/9-TLR inflammatory signaling as a common driving mechanism of genotoxic stress. Transcriptional activation of this signaling axis in the mesenchymal niche predicted leukemic evolution and progression-free survival in myelodysplastic syndrome (MDS), the principal leukemia predisposition syndrome. Collectively, our findings identify mesenchymal niche-induced genotoxic stress in heterotypic stem and progenitor cells through inflammatory signaling as a targetable determinant of disease outcome in human pre-leukemia.
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http://dx.doi.org/10.1016/j.stem.2016.08.021DOI Listing
November 2016

Inefficient DNA Repair Is an Aging-Related Modifier of Parkinson's Disease.

Cell Rep 2016 05 19;15(9):1866-75. Epub 2016 May 19.

Department of Molecular Genetics, Erasmus Medical Center, 3015 Rotterdam, the Netherlands. Electronic address:

The underlying relation between Parkinson's disease (PD) etiopathology and its major risk factor, aging, is largely unknown. In light of the causative link between genome stability and aging, we investigate a possible nexus between DNA damage accumulation, aging, and PD by assessing aging-related DNA repair pathways in laboratory animal models and humans. We demonstrate that dermal fibroblasts from PD patients display flawed nucleotide excision repair (NER) capacity and that Ercc1 mutant mice with mildly compromised NER exhibit typical PD-like pathological alterations, including decreased striatal dopaminergic innervation, increased phospho-synuclein levels, and defects in mitochondrial respiration. Ercc1 mouse mutants are also more sensitive to the prototypical PD toxin MPTP, and their transcriptomic landscape shares important similarities with that of PD patients. Our results demonstrate that specific defects in DNA repair impact the dopaminergic system and are associated with human PD pathology and might therefore constitute an age-related risk factor for PD.
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http://dx.doi.org/10.1016/j.celrep.2016.04.071DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4893155PMC
May 2016

Brain Radiation Information Data Exchange (BRIDE): integration of experimental data from low-dose ionising radiation research for pathway discovery.

BMC Bioinformatics 2016 May 11;17(1):212. Epub 2016 May 11.

Department of Genetics, Development & Molecular Biology, School of Biology, Aristotle University of Thessalonica, 54124, Thessalonica, Greece.

Background: The underlying molecular processes representing stress responses to low-dose ionising radiation (LDIR) in mammals are just beginning to be understood. In particular, LDIR effects on the brain and their possible association with neurodegenerative disease are currently being explored using omics technologies.

Results: We describe a light-weight approach for the storage, analysis and distribution of relevant LDIR omics datasets. The data integration platform, called BRIDE, contains information from the literature as well as experimental information from transcriptomics and proteomics studies. It deploys a hybrid, distributed solution using both local storage and cloud technology.

Conclusions: BRIDE can act as a knowledge broker for LDIR researchers, to facilitate molecular research on the systems biology of LDIR response in mammals. Its flexible design can capture a range of experimental information for genomics, epigenomics, transcriptomics, and proteomics. The data collection is available at: .
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http://dx.doi.org/10.1186/s12859-016-1068-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4865096PMC
May 2016

Editorial: Neuronal Self-Defense: Compensatory Mechanisms in Neurodegenerative Disorders.

Front Cell Neurosci 2015 5;9:499. Epub 2016 Jan 5.

Department of Genetics, Erasmus Medical Center Rotterdam, Netherlands.

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http://dx.doi.org/10.3389/fncel.2015.00499DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4700255PMC
January 2016

Metals and neurodegeneration.

Neurobiol Dis 2015 Sep;81:1-3

Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands. Electronic address:

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http://dx.doi.org/10.1016/j.nbd.2015.08.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4793913PMC
September 2015

Contractile Defect Caused by Mutation in MYBPC3 Revealed under Conditions Optimized for Human PSC-Cardiomyocyte Function.

Cell Rep 2015 Oct 17;13(4):733-745. Epub 2015 Oct 17.

Department of Anatomy and Embryology, Leiden University Medical Center, 2300 RC Leiden, the Netherlands. Electronic address:

Maximizing baseline function of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) is essential for their effective application in models of cardiac toxicity and disease. Here, we aimed to identify factors that would promote an adequate level of function to permit robust single-cell contractility measurements in a human induced pluripotent stem cell (hiPSC) model of hypertrophic cardiomyopathy (HCM). A simple screen revealed the collaborative effects of thyroid hormone, IGF-1 and the glucocorticoid analog dexamethasone on the electrophysiology, bioenergetics, and contractile force generation of hPSC-CMs. In this optimized condition, hiPSC-CMs with mutations in MYBPC3, a gene encoding myosin-binding protein C, which, when mutated, causes HCM, showed significantly lower contractile force generation than controls. This was recapitulated by direct knockdown of MYBPC3 in control hPSC-CMs, supporting a mechanism of haploinsufficiency. Modeling this disease in vitro using human cells is an important step toward identifying therapeutic interventions for HCM.
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http://dx.doi.org/10.1016/j.celrep.2015.09.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4644234PMC
October 2015

Neonatal Irradiation Leads to Persistent Proteome Alterations Involved in Synaptic Plasticity in the Mouse Hippocampus and Cortex.

J Proteome Res 2015 Nov 12;14(11):4674-86. Epub 2015 Oct 12.

Department of Genetics, Erasmus Medical Center , 3015 CE Rotterdam, The Netherlands.

Recent epidemiological data indicate that radiation doses as low as those used in computer tomography may result in long-term neurocognitive side effects. The aim of this study was to elucidate long-term molecular alterations related to memory formation in the brain after low and moderate doses of γ radiation. Female C57BL/6J mice were irradiated on postnatal day 10 with total body doses of 0.1, 0.5, or 2.0 Gy; the control group was sham-irradiated. The proteome analysis of hippocampus, cortex, and synaptosomes isolated from these brain regions indicated changes in ephrin-related, RhoGDI, and axonal guidance signaling. Immunoblotting and miRNA-quantification demonstrated an imbalance in the synapse morphology-related Rac1-Cofilin pathway and long-term potentiation-related cAMP response element-binding protein (CREB) signaling. Proteome profiling also showed impaired oxidative phosphorylation, especially in the synaptic mitochondria. This was accompanied by an early (4 weeks) reduction of mitochondrial respiration capacity in the hippocampus. Although the respiratory capacity was restored by 24 weeks, the number of deregulated mitochondrial complex proteins was increased at this time. All observed changes were significant at doses of 0.5 and 2.0 Gy but not at 0.1 Gy. This study strongly suggests that ionizing radiation at the neonatal state triggers persistent proteomic alterations associated with synaptic impairment.
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http://dx.doi.org/10.1021/acs.jproteome.5b00564DOI Listing
November 2015

Women have more potential to induce browning of perirenal adipose tissue than men.

Obesity (Silver Spring) 2015 Aug 14;23(8):1671-9. Epub 2015 Jul 14.

Department of Internal Medicine, Section of Endocrinology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.

Objective: Brown adipose tissue (BAT) can generate heat by burning fatty acids, a process mediated by uncoupling protein 1 (UCP1). White adipose tissue (WAT) depots can gain BAT-like properties, and various studies have suggested that females have more active BAT or BAT-like WAT. We studied sex differences in BAT-like properties of human perirenal adipose tissue.

Methods: Perirenal and subcutaneous adipose tissue was obtained from 20 male and 24 female healthy live kidney donors. Mesenchymal stem cells (MSCs), adipocyte precursor cells, were isolated from these depots to study whether intrinsic factors control BAT-like properties of the adipose tissue depots.

Results: When average outside temperature a week before harvesting was below 11°C, brown-like adipocytes expressing UCP1 were present in perirenal adipose tissue of women, but not of men. MSCs derived from perirenal adipose tissue expressed significantly more UCP1 when from female origin compared to male origin (P = 0.009). However, UCP1 protein content and oxygen consumption rate did not differ between adipocytes derived from male and female perirenal MSCs.

Conclusions: Female perirenal adipose tissue has a higher potency to gain BAT-like properties than male perirenal adipose tissue. The degree of gaining BAT-like properties depends on sex-specific intrinsic factors and environmental triggers such as temperature.
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http://dx.doi.org/10.1002/oby.21166DOI Listing
August 2015

Low-dose ionizing radiation rapidly affects mitochondrial and synaptic signaling pathways in murine hippocampus and cortex.

J Proteome Res 2015 May 6;14(5):2055-64. Epub 2015 Apr 6.

†Institute of Radiation Biology, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany.

The increased use of radiation-based medical imaging methods such as computer tomography is a matter of concern due to potential radiation-induced adverse effects. Efficient protection against such detrimental effects has not been possible due to inadequate understanding of radiation-induced alterations in signaling pathways. The aim of this study was to elucidate the molecular mechanisms behind learning and memory deficits after acute low and moderate doses of ionizing radiation. Female C57BL/6J mice were irradiated on postnatal day 10 (PND10) with gamma doses of 0.1 or 0.5 Gy. This was followed by evaluation of the cellular proteome, pathway-focused transcriptome, and neurological development/disease-focused miRNAome of hippocampus and cortex 24 h postirradiation. Our analysis showed that signaling pathways related to mitochondrial and synaptic functions were changed by acute irradiation. This may lead to reduced mitochondrial function paralleled by enhanced number of dendritic spines and neurite outgrowth due to elevated long-term potentiation, triggered by increased phosphorylated CREB. This was predominately observed in the cortex at 0.1 and 0.5 Gy and in the hippocampus only at 0.5 Gy. Moreover, a radiation-induced increase in the expression of several neural miRNAs associated with synaptic plasticity was found. The early changes in signaling pathways related to memory formation may be associated with the acute neurocognitive side effects in patients after brain radiotherapy but might also contribute to late radiation-induced cognitive injury.
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http://dx.doi.org/10.1021/acs.jproteome.5b00114DOI Listing
May 2015

Direct activating effects of adrenocorticotropic hormone (ACTH) on brown adipose tissue are attenuated by corticosterone.

FASEB J 2014 Nov 1;28(11):4857-67. Epub 2014 Aug 1.

Department of Internal Medicine, Section of Endocrinology, and.

Brown adipose tissue (BAT) and brown-like cells in white adipose tissue (WAT) can dissipate energy through thermogenesis, a process mediated by uncoupling protein 1 (UCP1). We investigated whether stress hormones ACTH and corticosterone contribute to BAT activation and browning of WAT. ACTH and corticosterone were studied in male mice exposed to 4 or 23°C for 24 h. Direct effects were studied in T37i mouse brown adipocytes and primary cultured murine BAT and inguinal WAT (iWAT) cells. In vivo effects were studied using (18)F-deoxyglucose positron emission tomography. Cold exposure doubled serum ACTH concentrations (P=0.03) and fecal corticosterone excretion (P=0.008). In T37i cells, ACTH dose-dependently increased Ucp1 mRNA (EC50=1.8 nM) but also induced Ucp1 protein content 88% (P=0.02), glycerol release 32% (P=0.03) and uncoupled respiration 40% (P=0.003). In cultured BAT and iWAT, ACTH elevated Ucp1 mRNA by 3-fold (P=0.03) and 3.7-fold (P=0.01), respectively. In T37i cells, corticosterone prevented induction of Ucp1 mRNA and Ucp1 protein by both ACTH and norepinephrine in a glucocorticoid receptor (GR)-dependent fashion. ACTH and GR antagonist RU486 independently doubled BAT (18)F-deoxyglucose uptake (P=0.0003 and P=0.004, respectively) in vivo. Our results show that ACTH activates BAT and browning of WAT while corticosterone counteracts this.
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http://dx.doi.org/10.1096/fj.14-254839DOI Listing
November 2014

Mitochondrial DNA damage: molecular marker of vulnerable nigral neurons in Parkinson's disease.

Neurobiol Dis 2014 Oct 27;70:214-23. Epub 2014 Jun 27.

Pittsburgh Institute for Neurodegenerative Diseases and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15260, USA. Electronic address:

DNA damage can cause (and result from) oxidative stress and mitochondrial impairment, both of which are implicated in the pathogenesis of Parkinson's disease (PD). We therefore examined the role of mitochondrial DNA (mtDNA) damage in human postmortem brain tissue and in in vivo and in vitro models of PD, using a newly adapted histochemical assay for abasic sites and a quantitative polymerase chain reaction (QPCR)-based assay. We identified the molecular identity of mtDNA damage to be apurinic/apyrimidinic (abasic) sites in substantia nigra dopamine neurons, but not in cortical neurons from postmortem PD specimens. To model the systemic mitochondrial impairment of PD, rats were exposed to the pesticide rotenone. After rotenone treatment that does not cause neurodegeneration, abasic sites were visualized in nigral neurons, but not in cortex. Using a QPCR-based assay, a single rotenone dose induced mtDNA damage in midbrain neurons, but not in cortical neurons; similar results were obtained in vitro in cultured neurons. Importantly, these results indicate that mtDNA damage is detectable prior to any signs of degeneration - and is produced selectively in midbrain neurons under conditions of mitochondrial impairment. The selective vulnerability of midbrain neurons to mtDNA damage was not due to differential effects of rotenone on complex I since rotenone suppressed respiration equally in midbrain and cortical neurons. However, in response to complex I inhibition, midbrain neurons produced more mitochondrial H2O2 than cortical neurons. We report selective mtDNA damage as a molecular marker of vulnerable nigral neurons in PD and suggest that this may result from intrinsic differences in how these neurons respond to complex I defects. Further, the persistence of abasic sites suggests an ineffective base excision repair response in PD.
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http://dx.doi.org/10.1016/j.nbd.2014.06.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4144978PMC
October 2014

PGC-1α and reactive oxygen species regulate human embryonic stem cell-derived cardiomyocyte function.

Stem Cell Reports 2013 12;1(6):560-74. Epub 2013 Dec 12.

Leiden University Medical Center, 2300RC Leiden, The Netherlands.

Diminished mitochondrial function is causally related to some heart diseases. Here, we developed a human disease model based on cardiomyocytes from human embryonic stem cells (hESCs), in which an important pathway of mitochondrial gene expression was inactivated. Repression of PGC-1α, which is normally induced during development of cardiomyocytes, decreased mitochondrial content and activity and decreased the capacity for coping with energetic stress. Yet, concurrently, reactive oxygen species (ROS) levels were lowered, and the amplitude of the action potential and the maximum amplitude of the calcium transient were in fact increased. Importantly, in control cardiomyocytes, lowering ROS levels emulated this beneficial effect of PGC-1α knockdown and similarly increased the calcium transient amplitude. Our results suggest that controlling ROS levels may be of key physiological importance for recapitulating mature cardiomyocyte phenotypes, and the combination of bioassays used in this study may have broad application in the analysis of cardiac physiology pertaining to disease.
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http://dx.doi.org/10.1016/j.stemcr.2013.11.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3871390PMC
May 2015

Defects in mitochondrial clearance predispose human monocytes to interleukin-1β hypersecretion.

J Biol Chem 2014 Feb 19;289(8):5000-12. Epub 2013 Dec 19.

From the Department of Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht, Wilhelmina Children's Hospital, 3584 EA Utrecht, The Netherlands.

Most hereditary periodic fever syndromes are mediated by deregulated IL-1β secretion. The generation of mature IL-1β requires two signals: one that induces synthesis of inflammasome components and substrates and a second that activates inflammasomes. The mechanisms that mediate autoinflammation in mevalonate kinase deficiency, a periodic fever disease characterized by a block in isoprenoid biosynthesis, are poorly understood. In studying the effects of isoprenoid shortage on IL-1 β generation, we identified a new inflammasome activation signal that originates from defects in autophagy. We find that hypersecretion of IL-1β and IL-18 requires reactive oxygen species and is associated with an oxidized redox status of monocytes but not lymphocytes. IL-1β hypersecretion by monocytes involves decreased mitochondrial stability, release of mitochondrial content into the cytosol and attenuated autophagosomal degradation. Defective autophagy, as established by ATG7 knockdown, results in prolonged cytosolic retention of damaged mitochondria and increased IL-1β secretion. Finally, activation of autophagy in healthy but not mevalonate kinase deficiency patient cells reduces IL-1β secretion. Together, these results indicate that defective autophagy can prime monocytes for mitochondria-mediated NLRP3 inflammasome activation, thereby contributing to hypersecretion of IL-1β in mevalonate kinase deficiency.
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http://dx.doi.org/10.1074/jbc.M113.536920DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3931060PMC
February 2014

Expression of Ambra1 in mouse brain during physiological and Alzheimer type aging.

Neurobiol Aging 2014 Jan 2;35(1):96-108. Epub 2013 Aug 2.

Department of Sciences, University "Roma Tre", Rome, Italy; Department of Genetics, Erasmus Medical Center, Rotterdam, the Netherlands.

Autophagy is a major protein degradation pathway, essential for stress-induced and constitutive protein turnover. In nervous tissue, autophagy is constitutively active and crucial to neuronal survival. The efficiency of the autophagic pathway reportedly undergoes age-related decline, and autophagy defects are observed in neurodegenerative diseases. Since Ambra1 plays a fundamental role in regulating the autophagic process in developing nervous tissue, we investigated the expression of this protein in mature mouse brain and during physiological and Alzheimer type aging. The present study accomplished the first complete map of Ambra1 protein distribution in the various brain areas, and highlights differential expression in neuronal/glial cell populations. Differences in Ambra1 content are possibly related to specific neuronal features and properties, particularly concerning susceptibility to neurodegeneration. Furthermore, the analysis of Ambra1 expression in physiological and pathological brain aging supports important, though conflicting, functions of autophagy in neurodegenerative processes. Thus, novel therapeutic approaches, based on autophagy modulation, should also take into account the age-dependent roles of this mechanism in establishing, promoting, or counteracting neurodegeneration.
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http://dx.doi.org/10.1016/j.neurobiolaging.2013.07.001DOI Listing
January 2014

Nucleotide excision repair in chronic neurodegenerative diseases.

DNA Repair (Amst) 2013 Aug 28;12(8):568-77. Epub 2013 May 28.

Department of Genetics, Erasmus Medical Center, Rotterdam, The Netherlands.

Impaired DNA repair involving the nucleotide excision repair (NER)/transcription-coupled repair (TCR) pathway cause human pathologies associated with severe neurological symptoms. These clinical observations suggest that defective NER/TCR might also play a critical role in chronic neurodegenerative disorders (ND), such as Alzheimer's and Parkinson's disease. Involvement of NER/TCR in these disorders is also substantiated by the evidence that aging constitutes the principal risk factor for chronic ND and that this DNA repair mechanism is very relevant for the aging process itself. Our understanding of the exact role of NER/TCR in chronic ND, however, is extremely rudimentary; while there is no doubt that defective NER/TCR can lead to neuronal death, evidence for its participation in the etiopathogenesis of ND is inconclusive thus far. Here we summarize the experimental observations supporting a role for NER/TCR in chronic ND and suggest questions and lines of investigation that might help in addressing this important issue. We also present a preliminary yet unprecedented meta-analysis on human brain microarray data to understand the expression levels of the various NER factors in the anatomical areas relevant for chronic ND pathogenesis. In summary, this review intends to highlight elements supporting a role of NER/TCR in these devastating disorders and to propose potential strategies of investigation.
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http://dx.doi.org/10.1016/j.dnarep.2013.04.009DOI Listing
August 2013

Thiol oxidation and altered NR2B/NMDA receptor functions in in vitro and in vivo pilocarpine models: implications for epileptogenesis.

Neurobiol Dis 2013 Jan 21;49:87-98. Epub 2012 Jul 21.

Pittsburgh Institute for Neurodegenerative Diseases and Department of Neurology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA. Electronic address:

Hippocampal sclerosis, the main pathological sign of chronic temporal lobe epilepsy (TLE), is associated with oxidative injury, altered N-methyl d-aspartate receptor (NMDAR) stoichiometry, and loss of hippocampal neurons. However, the mechanisms that drive the chronic progression of TLE remain elusive. Our previous studies have shown that NADPH oxidase activation and ERK 1/2 phosphorylation are required for the up-regulation of the predominantly pre-synaptic NR2B subunit auto-receptor in both in vitro and in vivo pilocarpine (PILO) models of TLE. To provide further understanding of the cellular responses during the early-stages of hyper excitability, we investigated the role of oxidative damage and altered NR2B functions. In rat primary hippocampal cultures, we found that N-acetylcysteine (NAC) prevented PILO-mediated thiol oxidation, apoptosis, cell death and NR2B subunit over-expression. Interestingly, NAC did not block thiol oxidation when added to the neurons 6h after the PILO exposure, suggesting that disulfide formation could rapidly become an irreversible phenomenon. Moreover, NAC pre-treatment did not prevent PILO-induced NR2A subunit over-expression, a critical event in hippocampal sclerosis. Pre-treatment with the highly specific NR2B subunit inhibitor, ifenprodil, partially decreased PILO-mediated thiol oxidation and was not effective in preventing apoptosis and cell death. However, if acutely administered 48h after PILO exposure, ifenprodil blocked glutamate-induced aberrant calcium influx, suggesting the crucial role of NR2B over-expression in triggering neuronal hyper-excitability. Furthermore, ifenprodil treatment was able to prevent NR2A subunit over-expression by means of ERK1/2 phosphorylation. Our findings indicate oxidative stress and NR2B/NMDA signaling as promising therapeutic targets for co-treatments aimed to prevent chronic epilepsy following the seizure onset.
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http://dx.doi.org/10.1016/j.nbd.2012.07.013DOI Listing
January 2013

Pilocapine alters NMDA receptor expression and function in hippocampal neurons: NADPH oxidase and ERK1/2 mechanisms.

Neurobiol Dis 2011 Jun 17;42(3):482-95. Epub 2011 Mar 17.

Pittsburgh Institute for Neurodegenerative Diseases and Department of Neurology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA.

The molecular basis for epileptogenesis remains poorly defined, but repeated or prolonged seizures can cause altered hippocampal N-methyl D-aspartate receptor (NMDAR) stoichiometry, loss of hippocampal neurons, and aberrant mossy fiber sprouting. Using the muscarinic receptor 1 (m1R) agonist, pilocarpine (PILO), in hippocampal cell cultures we explored the early sequence of molecular events that occur within 24h of the initial insult and result in altered neuronal function during epileptogenesis. Our findings show that PILO-induced, m1R-mediated, inositol 1,4,5-trisphosphate (IP3) synthesis constitutes an early, crucial biochemical event required for NMDAR hyperactivation and subsequent NADPH oxidase (NOX) activation and NMDAR-independent ERK1/2 phoshorylation. Together, but not separately, NOX activation and ERK1/2 phosphorylation induce alterations in NMDAR stoichiometry through the upregulation of NR1 and NR2B subunits. Lastly, we demonstrated that PILO-mediated oxidative stress alters NMDAR function through the redox modulation of cysteine residues. The in vitro results related to thiol oxidation, NOX activation, ERK1/2 phosphorylation and NMDAR upregulation were confirmed in vivo, 24h after treatment of adult rats with PILO. These results obtained in PILO-treated primary hippocampal neurons--and confirmed in vivo at the same time-point after PILO--provide a better understanding of the early cellular responses during epileptogenesis and identify potential therapeutic targets to prevent development of chronic epilepsy.
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http://dx.doi.org/10.1016/j.nbd.2011.02.012DOI Listing
June 2011

Single-cell redox imaging demonstrates a distinctive response of dopaminergic neurons to oxidative insults.

Antioxid Redox Signal 2011 Aug 6;15(4):855-71. Epub 2011 Jun 6.

Medical Scientist Training Program, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.

Aims: The study of the intracellular oxido-reductive (redox) state is of extreme relevance to the dopamine (DA) neurons of the substantia nigra pars compacta. These cells possess a distinct physiology intrinsically associated with elevated reactive oxygen species production, and they selectively degenerate in Parkinson's disease under oxidative stress conditions. To test the hypothesis that these cells display a unique redox response to mild, physiologically relevant oxidative insults when compared with other neuronal populations, we sought to develop a novel method for quantitatively assessing mild variations in intracellular redox state.

Results: We have developed a new imaging strategy to study redox variations in single cells, which is sensitive enough to detect changes within the physiological range. We studied DA neurons' physiological redox response in biological systems of increasing complexity--from primary cultures to zebrafish larvae, to mammalian brains-and identified a redox response that is distinctive for substantia nigra pars compacta DA neurons. We studied simultaneously, and in the same cells, redox state and signaling activation and found that these phenomena are synchronized.

Innovation: The redox histochemistry method we have developed allows for sensitive quantification of intracellular redox state in situ. As this method is compatible with traditional immunohistochemical techniques, it can be applied to diverse settings to investigate, in theory, any cell type of interest.

Conclusion: Although the technique we have developed is of general interest, these findings provide insights into the biology of DA neurons in health and disease and may have implications for therapeutic intervention.
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http://dx.doi.org/10.1089/ars.2010.3629DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3135271PMC
August 2011