Publicaciones por año
Publicaciones del Departamento de Histología y Embriología
Lead exposure stimulates VEGF expression in the spinal cord and extends survival in a mouse model of ALS
Neurobiol Dis 2010 37(3):574-80
Ana G Barbeito 1, Laura Martinez-Palma 1, Marcelo R Vargas 2, Mariana Pehar 2, Nelly Mañay 3, Joseph S Beckman 4, Luis Barbeito 2, Patricia Cassina 1
1 Departamento de Histología y Embriología, Facultad de Medicina, Montevideo, Uruguay 2 Laboratorio de Neurobiologia Celular y Molecular, Instituto Clemente Estable and Institut Pasteur de Montevideo, Uruguay 3 Departamento de Toxicología, Facultad de Química, Montevideo, Uruguay 4 Department of Biochemistry and Biophysics, Environmental Health Sciences Center and Linus Pauling Institute, Oregon State University, Corvallis, Oregon
DOI: 10.1016/j.nbd.2009.11.007
PMID: 19914377
Pubmed: https://pubmed.ncbi.nlm.nih.gov/19914377
Texto completo: https://linkinghub.elsevier.com/retrieve/pii/S0969-9961(09)00329-5
Abstract:
Exposure to environmental lead (Pb) is a mild risk factor for amyotrophic lateral sclerosis (ALS), a paralytic disease characterized by progressive degeneration of motor neurons. However, recent evidence has paradoxically linked higher Pb levels in ALS patients with longer survival. We investigated the effects of low-level Pb exposure on survival of mice expressing the ALS-linked superoxide dismutase-1 G93A mutation (SOD1(G93A)). SOD1(G93A) mice exposed to Pb showed longer survival and increased expression of VEGF in the ventral horn associated with reduced astrocytosis. Pretreatment of cultured SOD1(G93A) astrocytes with low, non toxic Pb concentrations upregulated VEGF expression and significantly abrogated motor neuron loss in coculture, an effect prevented by neutralizing antibodies to VEGF. The actions of Pb on astrocytes might explain its paradoxical slowing of disease progression in SOD1(G93A) mice and the improved survival of ALS patients. Understanding how Pb stimulates astrocytic VEGF production and reduces neuroinflammation may yield a new therapeutic approach for treating ALS.
Hyperpolarization of the plasma membrane potential provokes reorganization of the actin cytoskeleton and increases the stability of adherens junctions in bovine corneal endothelial cells in culture
Cell Motil Cytoskeleton 2009 66(12):1087-99
Verónica Nin 1, Julio A Hernández 2, Silvia Chifflet 3
1 Departamento de Histología y Embriología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay 2 Sección Biofísica, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay 3 Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
DOI: 10.1002/cm.20416
PMID: 19753628
Pubmed: https://pubmed.ncbi.nlm.nih.gov/19753628
Texto completo: https://doi.org/10.1002/cm.20416
Abstract:
In previous works we showed that the depolarization of the plasma membrane potential (PMP) determines a reorganization of the cytoskeleton of diverse epithelia in culture, consisting mainly of a reallocation of peripheral actin toward the cell center, ultimately provoking intercellular disruption. In view of this evidence, we explored in this study the possible effects of membrane potential hyperpolarization on the cytoskeletal organization and adherens junction (AJ) morphology and the stability of confluent bovine corneal endothelial cells in culture. For this purpose, hyperpolarization was achieved by substitution of extracellular sodium by nondiffusible cations or via the incorporation of valinomycin to the control solution. Actin compactness at the cell periphery was assessed by quantitative analysis of fluorescence microscopy images. The stability of the AJ was challenged by calcium deprivation or temperature decrease. Our results showed that plasma membrane hyperpolarization provokes a compaction of AJ-associated actin filaments toward the plasma membrane and an increase in the stability of the AJs. We also observed that the hyperpolarizing procedures determined similar modifications in the actin cytoskeleton of endothelial cells in whole bovine corneas. Together with our previous work, the results of this study contribute to the idea that modifications in the PMP of nonexcitable cells participate in cellular adaptive responses involving reorganization of cytoskeletal components.
Axonal mitochondrial clusters containing mutant SOD1 in transgenic models of ALS
Antioxid Redox Signal 2009 11(7):1535-45
Jose R Sotelo-Silveira 1 2 5, Paola Lepanto 1, Victoria Elizondo 1, Sofia Horjales 2, Florencia Palacios 2, Laura Martinez-Palma 1, Monica Marin 2, Joseph S Beckman 3, Luis Barbeito 1 4
1 Department of Cell and Molecular Neurobiology, Instituto de Investigaciones Biologicas Clemente Estable, Montevideo, Uruguay. 2 Department of Cell and Molecular Biology, Facultad de Ciencias, Montevideo, Uruguay. 3 Environmental Health Sciences Center, Oregon State University, Corvallis, Oregon. 4 Institut Pasteur de Montevideo, Montevideo, Uruguay. 5 Present address of Dr. Sotelo-Silveira: Laboratory of Molecular Technology, ATP, SAIC-National Cancer Institute, Frederick, Maryland.
DOI: 10.1089/ars.2009.2614
PMID: 19344250
Pubmed: https://pubmed.ncbi.nlm.nih.gov/19344250
Texto completo: https://www.liebertpub.com/doi/10.1089/ars.2009.2614
Abstract:
We studied the subcellular distribution of mitochondria and superoxide dismutase-1 (SOD1) in whole mounts of microdissected motor axons of rats expressing the ALS-linked SOD1-G93A mutation. The rationale was to determine whether physical interactions between the enzyme and mitochondria were linked to the axonopathy of motor fibers occurring in amyotrophic lateral sclerosis (ALS). Mitochondria and SOD1 displayed a homogeneous distribution along motor axons both in nontransgenic rats and in those overexpressing wild-type SOD1. In contrast, axons from SOD1-G93A rats (older than 35 days) showed accumulation of mitochondria in discrete clusters located at regular intervals. Most of SOD1 immunoreactivity was enriched in these clusters and colocalized with mitochondria, suggesting a recruitment of SOD1-G93A to the organelle. The SOD1/mitochondrial clusters were abundant in motor axons but scarcely seen in sensory axons. Clusters also were stained for neuronal nitric oxide synthase, nitrotyrosine, and cytochrome c. The later also was detected surrounding clusters. Ubiquitin colocalized with clusters only at late stages of the disease. The cytoskeleton was not overtly altered in clusters. These results suggest that mutant SOD1 and defective mitochondria create localized dysfunctional domains in motor axons, which may lead to progressive axonopathy in ALS.
Mitochondrial calcium overload triggers complement-dependent superoxide-mediated programmed cell death in Trypanosoma cruzi
Biochem J 2009 418(3):595-604
Florencia Irigoín 1 2, Natalia M Inada 3, Mariana P Fernandes 3, Lucía Piacenza 2 4, Fernanda R Gadelha 5, Anibal E Vercesi 3, Rafael Radi 2 4
1 Departamento de Histología y Embriología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay 2 Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Avda. Gral. Flores 2125, 11800 Montevideo, Uruguay 3 Labóratorio de Bioenergética, Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Unicamp, Campinas, Brazil 4 Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay 5 Instituto de Biologia, Unicamp, Campinas, Brazil
DOI: 10.1042/BJ20081981
PMID: 19053945
Pubmed: https://pubmed.ncbi.nlm.nih.gov/19053945
Texto completo: https://portlandpress.com/biochemj/article-lookup/doi/10.1042/BJ20081981
Abstract:
The epimastigote stage of Trypanosoma cruzi undergoes PCD (programmed cell death) when exposed to FHS (fresh human serum). Although it has been known for over 30 years that complement is responsible for FHS-induced death, the link between complement activation and triggering of PCD has not been established. We have previously shown that the mitochondrion participates in the orchestration of PCD in this model. Several changes in mitochondrial function were described, and in particular it was shown that mitochondrion-derived O(2)(*-) (superoxide radical) is necessary for PCD. In the present study, we establish mitochondrial Ca(2+) overload as the link between complement deposition and the observed changes in mitochondrial physiology and the triggering of PCD. We show that complement activation ends with the assembly of the MAC (membrane attack complex), which allows influx of Ca(2+) and release of respiratory substrates to the medium. Direct consequences of these events are accumulation of Ca(2+) in the mitochondrion and decrease in cell respiration. Mitochondrial Ca(2+) causes partial dissipation of the inner membrane potential and consequent mitochondrial uncoupling. Moreover, we provide evidence that mitochondrial Ca(2+) overload is responsible for the increased O(2)(*-) production, and that if cytosolic Ca(2+) rise is not accompanied by the accumulation of the cation in the mitochondrion and consequent production of O(2)(*-), epimastigotes die by necrosis instead of PCD. Thus our results suggest a model in which MAC assembly on the parasite surface allows Ca(2+) entry and its accumulation in the mitochondrion, leading to O(2)(*-) production, which in turn constitutes a PCD signal.
Prepubertal estrogen exposure modifies neurotrophin receptor expression in celiac neurons and alters ovarian innervation
Auton Neurosci 2009 Jan 28;145(1-2):35-43
Gabriel Anesetti 1, Paula Lombide 1 2, Rebeca Chávez-Genaro 1
1 Departamento de Histología y Embriología, Facultad de Medicina, Universidad de la República, General Flores 2125, CP 11800, Uruguay 2 Departamento de Morfología y Desarrollo, Facultad de Veterinaria, Lasplaces 1550, CP 11600, Universidad de la República, Montevideo, Uruguay
DOI: 10.1016/j.autneu.2008.10.021
PMID: 19036644
Pubmed: https://pubmed.ncbi.nlm.nih.gov/19036644
Texto completo: https://linkinghub.elsevier.com/retrieve/pii/S1566-0702(08)00195-1
Abstract:
Estradiol is a key hormone in the regulation of reproductive processes acting both on peripheral organs and sympathetic neurons associated to reproductive function. However, many of its regulatory effects on the development and function on the sympathetic neurons have not been completely clarified. Sympathetic neurons located in the celiac ganglion projects to visceral, vascular and glandular targets, and contribute to ovarian innervation, being the main source of sympathetic fibers. In the present study, we analyze the effects of elevated levels of exogenous estrogen during the prepubertal period in post-ganglionic sympathetic neurons. Estrogen exposure induced a significant increase in sympathetic celiac neuronal size and modified the expression of neurotrophin receptor p75. This change affected mainly small and medium size neurons. The effect of estrogens on innervation of celiac target organs was heterogeneous, inducing a significant increase in catecholaminergic innervation of the ovary, but not of the pyloric muscular layers. These findings further support the role of estrogen as a modulator of neuronal plasticity and suggest that estrogen could modify some features involved in the relation between sympathetic immature peripheral neurons and their target organs throughout a neurotrophin-dependent mechanism.
Sensory processing in the fast electrosensory pathway of pulse gymnotids studied at multiple integrative levels
Comp Biochem Physiol A Mol Integr Physiol 2008 Nov;151(3):370-380
María E Castelló 1 , Javier Nogueira 1 , Omar Trujillo-Cenóz 2 , Angel A Caputi 3
1 Departamento de Neurociencias Integrativas y Computacionales, Instituto de Investigaciones Biológicas Clemente Estable, Unidad Asociada de la Facultad de Ciencias, Universidad de la República. Montevideo, Av Italia 3318, 11600, Uruguay; Departamento de Histología y Embriología, Facultad de Medicina, Universidad de la República. Montevideo, Uruguay. 2 Departamento de Neuroanatomía Comparada, Instituto de Investigaciones Biológicas Clemente Estable, Unidad Asociada de la Facultad de Ciencias, Universidad de la República. Montevideo, Uruguay. 3 Departamento de Neurociencias Integrativas y Computacionales, Instituto de Investigaciones Biológicas Clemente Estable, Unidad Asociada de la Facultad de Ciencias, Universidad de la República. Montevideo, Av Italia 3318, 11600, Uruguay. Electronic address: angel@iibce.edu.uy.
DOI: 10.1016/j.cbpa.2007.04.012
PMID: 17513149
Pubmed: https://pubmed.ncbi.nlm.nih.gov/17513149
Texto completo: https://linkinghub.elsevier.com/retrieve/pii/S1095-6433(07)00988-9
Abstract:
Pulse gymnotids extract information about the environment using the pulsed discharge of an electric organ. Cutaneous electroreceptor organs transduce and encode the changes that objects imprint on the self-generated transcutaneous electric field. This review deals with the role of a neural circuit, the fast electrosensory path of pulse gymnotids, in the streaming of self generated electrosensory signals. The activation of this path triggers a low-responsiveness window slightly shorter than the interval between electric organ discharges. This phenomenon occurs at the electrosensory lateral line lobe where primary afferent terminals project on the somata of spherical neurons. The main subservient mechanism of the low-responsiveness window rely on the intrinsic properties of spherical neurons (dominated by a voltage dependent, low-threshold, non-inactivating and slowly-deactivating K(+) conductance) determining the cell to respond with a single spike followed by a long refractory period. Externally generated signals that randomly occur within the interval between self-generated discharges are likely blocked by the low responsiveness window. Repetitive signals, as those emitted by conspecifics with a slightly lower rate, occur progressively at longer delays beyond the duration of the low responsiveness window. Transient increases of the discharge rate relocate the interference within the low-responsiveness window. We propose that this combination of sensory filtering and electromotor control favors the self-generated signals in detriment of other, securing the continuity of the electrolocation stream.
Insights into the redox biology of Trypanosoma cruzi: Trypanothione metabolism and oxidant detoxification
Free Radic Biol Med 2008 Sep 15;45(6):733-42
Florencia Irigoín 1 3, Lucía Cibils 2 3, Marcelo A Comini 4, Shane R Wilkinson 5, Leopold Flohé 6, Rafael Radi 2 3
1 Departmento de Histología y Embriología, Facultad de Medicina, Universidad de la República, Uruguay 2 Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Uruguay 3 Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Uruguay 4 Biochemie-Zentrum der Universität Heidelberg, 69120 Heidelberg, Germany 5 School of Biological and Chemical Sciences, Queen Mary University of London, London, UK 6 MOLISA GmbH, 39118 Magdeburg, Germany
DOI: 10.1016/j.freeradbiomed.2008.05.028
PMID: 18588970
Pubmed: https://pubmed.ncbi.nlm.nih.gov/18588970
Texto completo: https://www.sciencedirect.com/science/article/abs/pii/S089158490800347X?via%3Dihub
Abstract:
Trypanosoma cruzi is the etiologic agent of Chagas' disease, an infection that affects several million people in Latin America. With no immediate prospect of a vaccine and problems associated with current chemotherapies, the development of new treatments is an urgent priority. Several aspects of the redox metabolism of this parasite differ enough from those in the mammalian host to be considered targets for drug development. Here, we review the information about a trypanosomatid-specific molecule centrally involved in redox metabolism, the dithiol trypanothione, and the main effectors of cellular antioxidant defense. We focus mainly on data from T. cruzi, making comparisons with other trypanosomatids whenever possible. In these parasites trypanothione participates in crucial thiol-disulfide exchange reactions and serves as electron donor in different metabolic pathways, from synthesis of DNA precursors to oxidant detoxification. Interestingly, the levels of several enzymes involved in trypanothione metabolism and oxidant detoxification increase during the transformation of T. cruzi to its mammalian-infective form and the overexpression of some of them has been associated with increased resistance to macrophage-dependent oxidative killing. Together, the evidence suggests a central role of the trypanothione-dependent antioxidant systems in the infection process.
Toll receptor 4 Asp299Gly polymorphism and its association with preterm birth and premature rupture of membranes in a South American population
Mol Hum Reprod 2008 Sep;14(9):555-9
G Rey 1, F Skowronek 1, J Alciaturi 1, J Alonso 2, B Bertoni 3, R Sapiro 1 4
1 Laboratory of Molecular Biology of Reproduction, Department of Histology and Embryology, School of Medicine, Gral. Flores 2125, CP 11800 Montevideo, Uruguay 2 Department of Obstetrics and Gynecology, C Pereira Rossell Hospital, School of Medicine, University of Uruguay, Montevideo, Uruguay 3 Department of Genetics, School of Medicine, University of Uruguay, Montevideo, Uruguay 4 Correspondence address. Tel: +598-2924-3414; E-mail: rsapiro@fmed.edu.uy
DOI: 10.1093/molehr/gan049
PMID: 18723631
Pubmed: https://pubmed.ncbi.nlm.nih.gov/18723631
Texto completo: https://academic.oup.com/molehr/article-lookup/doi/10.1093/molehr/gan049
Abstract:
Preterm birth (PTB) is a worldwide health problem and remains the leading cause of perinatal morbidity and mortality. Systemic and local intrauterine infections have been implicated in the pathogenesis of preterm labor and delivery. Common pathways between PTB, premature rupture of ovular membranes (PROM) and altered molecular routes of inflammation have been proposed. There is evidence to support a genetic component in these conditions. Lipopolysaccharide (LPS), a component of the cell wall of Gram-negative bacteria, is thought to play a key role in eliciting an inflammatory response. LPS is recognized by proteins of the innate immune system, including Toll-like receptor 4 (TLR4). Individuals from some European countries carrying the variant alleles resulting in an amino acid substitution (Asp299Gly) are at increased risk of Gram-negative infections and premature birth. The objective of this study was to determine if preterm newborns have different allele frequency of the Asp299Gly TLR4 variant from healthy term neonates in Uruguay. The impact of PROM was also examined. There was an increase in the risk for fetuses carrying the Asp299Gly substitution in TLR4 of being severely premature (<33 weeks) and to present PROM at the same time.
Mitochondrial dysfunction in SOD1G93A-bearing astrocytes promotes motor neuron degeneration: prevention by mitochondrial-targeted antioxidants
J Neurosci 2008 Apr 16;28(16):4115-22
Patricia Cassina 1 3, Adriana Cassina 2 3, Mariana Pehar 4, Raquel Castellanos 1, Mandi Gandelman 1 5, Andrés de León 1 5, Kristine M Robinson 7, Ronald P Mason 6, Joseph S Beckman 7, Luis Barbeito 3 4 5, Rafael Radi 2 3
1 Departamento de Histología, 2 Departamento de Bioquímica, and 3 Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, 11800 Montevideo, Uruguay, 4 Instituto de Investigaciones Biológicas Clemente Estable, 11600 Montevideo, Uruguay, 5 Neurodegeneration Laboratory, Institut Pasteur, 11400 Montevideo, Uruguay, 6 Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Science, National Institutes of Health, Research Triangle Park, North Carolina 27709, and 7 Department of Biochemistry and Biophysics, Linus Pauling Institute, Oregon State University, Corvallis, Oregon 97331
DOI: .1523/JNEUROSCI.5308-07.2008
PMID: 18417691
Pubmed: https://pubmed.ncbi.nlm.nih.gov/18417691
Texto completo: https://www.jneurosci.org/content/28/16/4115
Abstract:
Mitochondrial dysfunction and oxidative stress contribute to motor neuron degeneration in amyotrophic lateral sclerosis (ALS). Recent reports indicate that astrocytes expressing the mutations of superoxide dismutase-1 (SOD1) may contribute to motor neuron injury in ALS. Here, we provide evidence that mitochondrial dysfunction in SOD1(G93A) rat astrocytes causes astrocytes to induce apoptosis of motor neurons. Mitochondria from SOD1(G93A) rat astrocytes displayed a defective respiratory function, including decreased oxygen consumption, lack of ADP-dependent respiratory control, and decreased membrane potential. Protein 3-nitrotyrosine was detected immunochemically in mitochondrial proteins from SOD1(G93A) astrocytes, suggesting that mitochondrial defects were associated with nitroxidative damage. Furthermore, superoxide radical formation in mitochondria was increased in SOD1(G93A) astrocytes. Similar defects were found in mitochondria isolated from the spinal cord of SOD1(G93A) rats, and pretreatment of animals with the spin trap 5,5-dimethyl-1-pyrroline N-oxide restored mitochondrial function, forming adducts with mitochondrial proteins in vivo. As shown previously, SOD1(G93A) astrocytes induced death of motor neurons in cocultures, compared with nontransgenic ones. This behavior was recapitulated when nontransgenic astrocytes were treated with mitochondrial inhibitors. Remarkably, motor neuron loss was prevented by preincubation of SOD1(G93A) astrocytes with antioxidants and nitric oxide synthase inhibitors. In particular, low concentrations (approximately 10 nm) of two mitochondrial-targeted antioxidants, ubiquinone and carboxy-proxyl nitroxide, each covalently coupled to a triphenylphosphonium cation (Mito-Q and Mito-CP, respectively), prevented mitochondrial dysfunction, reduced superoxide production in SOD1(G93A) astrocytes, and restored motor neuron survival. Together, our results indicate that mitochondrial dysfunction in astrocytes critically influences motor neuron survival and support the potential pharmacological utility of mitochondrial-targeted antioxidants in ALS treatment.
Echinococcus granulosus: the establishment of the metacestode is associated with control of complement-mediated early inflammation
Exp Parasitol 2008 Feb;118(2):188-96
Martin Breijo 1 2, Gabriel Anesetti 3, Laura Martínez 3, Robert B Sim 4, Ana M Ferreira 2
1 Departamento de Ciencias Microbiológicas, Area Inmunología, Facultad de Veterinaria, Universidad de la República, A. Lasplaces 1620, Montevideo CP11600, Uruguay 2 Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República, Instituto de Higiene, Avda A. Navarro 3051, p2, Montevideo CP 11600, Uruguay 3 Departamento de Histología, Facultad de Veterinaria, Universidad de la República, A. Lasplaces 1620, Montevideo CP11600, Uruguay 4 MRC Immunochemistry Unit, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
DOI: 10.1016/j.exppara.2007.07.014
PMID: 17905232
Pubmed: https://pubmed.ncbi.nlm.nih.gov/17905232
Texto completo: https://linkinghub.elsevier.com/retrieve/pii/S0014-4894(07)00205-6
Abstract:
In this work we studied the evolution of early inflammation, complement activation and parasite survival/death along the establishment phase of Echinococcus granulosus metacestode. Using a chamber model of infection in mice, we examined cell infiltration and C3 deposition on individual parasites during their development from protoscoleces to cystic forms. We found that the intensity of the initial inflammation decreased around undamaged but not around damaged parasites: at 43dpi undamaged parasites were mostly associated with poor/mild inflammation while damaged parasites with a strong inflammation. In addition, whereas complement activation participated in the induction of early inflammation, the deposition of C3 on undamaged parasites progressively diminished. Interestingly, we observed some parasites in pre-cystic stage with no/poor C3 deposition at 3dpi. Overall, these results indicated that the establishment and survival of the hydatid cyst is associated with the control of complement and, consequently, of local inflammation at the initial phases of infection.