Publications by authors named "Silvana Allodi"

69 Publications

Cell proliferation in the central nervous system of an adult semiterrestrial crab.

Cell Tissue Res 2021 Feb 18. Epub 2021 Feb 18.

Programa de Pós-Graduação em Ciências Biológicas - Fisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro-UFRJ, Rio de Janeiro, RJ, 21941-590, Brazil.

Neurogenesis occurs in adults of most organisms, both vertebrates and invertebrates. In semiterrestrial crabs of the infraorder Brachyura, the deutocerebrum, where neurogenesis occurs, processes the olfactory sensory information from the antennae. The deutocerebrum is composed of a pair of olfactory lobes associated with cell clusters 9 and 10 (Cl 9 and Cl 10), containing proliferating cells. Because the location of the neurogenic niche in brachyuran semiterrestrial crabs has not been defined, here we describe a neurogenic niche in the central olfactory system of the crab Ucides cordatus and report two types of glial cells in the deutocerebrum, based on different markers. Serotonin (5-hydroxytryptamine) labeling was used to reveal neuroanatomical aspects of the central olfactory system and the neurogenic niche. The results showed a zone of proliferating neural cells within Cl 10, which also contains III beta-tubulin (Tuj1)+ immature neurons, associated with a structure that has characteristics of the neurogenic niche. For the first time, using two glial markers, glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS), we identified two types of astrocyte-like cells in different regions of the deutocerebrum. This study adds to the understanding of neurogenesis in a brachyuran semiterrestrial crustacean and encourages comparative studies between crustaceans and vertebrates, including mammals, based on shared aspects of both mechanisms of neurogenesis and regenerative potentials.
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http://dx.doi.org/10.1007/s00441-021-03413-yDOI Listing
February 2021

Progressive muscle-strength protocol for the functionality of upper limbs and quality of life in individuals with Parkinson's disease: Pilot study.

Complement Ther Med 2020 Aug 23;52:102432. Epub 2020 May 23.

Graduate Program of Physical Education, Universidade Federal do Rio de Janeiro, Brazil; Institute of Neurology Deolindo Couto, Universidade Federal do Rio de Janeiro, Brazil. Electronic address:

The effects of physical-therapy intervention on the motor function of upper limbs and the quality of life in patients with Parkinson's disease (PD) are not fully understood. We evaluated the effects of a progressive muscle-strengthening protocol for upper limbs on the functionality and quality of life. Patients were divided into two groups: Intervention (n = 6) and Control (n = 7). Assessment tools used were: Unified Parkinson's Disease Rating Scale (UPDRS), Parkinson's Disease Questionnaire, Nine-Hole Peg Test (9HPT), Test d'Évaluation des Membres Supérieurs de Personnes Âgées (TEMPA), 10-Repetition Maximum (10-RM) and handgrip dynamometer, which were applied pre- and post-intervention, with follow-up for one month after the last training session. Only, the Intervention group (post-intervention) showed significant statistical differences, with the following outcomes: UPDRS III (p = 0.042); 9HPT, right (p = 0.028) and left side (p = 0.028); TEMPA for total right side (p = 0.028), left side (p = 0.028) and total bilateral tasks (p = 0.028); TEMPA task 2 - open a jar and take a spoonful of coffee (p = 0.028), task 3 - pick up a pitcher and pour water into a glass for right (p = 0.046) and left side (p = 0.028), task 5 - write on an envelope and stick on a stamp (p = 0.028), and task 6 - shuffle and deal playing cards (p = 0.028). We observed significant statistical differences between groups (post-intervention) for TEMPA task 6 (p = 0.032), total right side (p = 0.032), and total bilateral tasks (p = 0.032). An increase in the maximum load in the post-intervention stage, based on the 10-RM test, was observed on the right (p = 0.003) and left (p = 0.007) sides. Our results showed an improvement in upper-limb functionality in PD patients submitted to progressive muscle-strength training, although not in quality of life.
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http://dx.doi.org/10.1016/j.ctim.2020.102432DOI Listing
August 2020

Lipid Rafts from Olfactory Ensheathing Cells: Molecular Composition and Possible Roles.

Cell Mol Neurobiol 2021 Apr 15;41(3):525-536. Epub 2020 May 15.

Laboratório de Neurobiologia do Desenvolvimento, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, CCS. Bloco G, Rio de Janeiro, 21941-902, Brazil.

Olfactory ensheathing cells (OECs) are specialized glial cells of the olfactory system, believed to play a role in the continuous production of olfactory neurons and ensheathment of their axons. Although OECs are used in therapeutic applications, little is known about the cellular mechanisms underlying their migratory behavior. Recently, we showed that OEC migration is sensitive to ganglioside blockage through A2B5 and Jones antibody in OEC culture. Gangliosides are common components of lipid rafts, where they participate in several cellular mechanisms, including cell migration. Here, we characterized OEC lipid rafts, analyzing the presence of specific proteins and gangliosides that are commonly expressed in motile neural cells, such as young neurons, oligodendrocyte progenitors, and glioma cells. Our results showed that lipid rafts isolated from OECs were enriched in cholesterol, sphingolipids, phosphatidylcholine, caveolin-1, flotillin-1, gangliosides GM1 and 9-O-acetyl GD3, A2B5-recognized gangliosides, CNPase, α-actinin, and β1-integrin. Analysis of the actin cytoskeleton of OECs revealed stress fibers, membrane spikes, ruffled membranes and lamellipodia during cell migration, as well as the distribution of α-actinin in membrane projections. This is the first description of α-actinin and flotillin-1 in lipid rafts isolated from OECs and suggests that, together with β1-integrin and gangliosides, membrane lipid rafts play a role during OEC migration. This study provides new information on the molecular composition of OEC membrane microdomains that can impact on our understanding of the role of OEC lipid rafts under physiological and pathological conditions of the nervous system, including inflammation, hypoxia, aging, neurodegenerative diseases, head trauma, brain tumor, and infection.
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http://dx.doi.org/10.1007/s10571-020-00869-4DOI Listing
April 2021

Measurement properties from the Brazilian Portuguese version of the QUIP-RS.

NPJ Parkinsons Dis 2020 13;6. Epub 2020 Feb 13.

1Programa de Pós-Graduação em Educação Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.

Parkinson's disease (PD) has numerous motor and non-motor symptoms. Among non-motor manifestations impulse control disorders (ICDs) stand out. ICDs include compulsions for gambling, shopping, eating, and sexual behavior, and "related disorders" such as hobbyism, simple motor activities, and dopamine dysregulation syndrome. There is no rating scale translated and adapted transculturally into Brazilian Portuguese language. Therefore, we cross-culturally adapted and investigated the measurement properties of the Brazilian version of the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale (QUIP-RS). Fifty-three patients participated in the study. Inter-evaluator and test-retest (patient and health professional) reliabilities (intraclass correlation coefficient) were all excellent (0.93, 0.93, and 0.99). The internal consistency was high ( = 0.92). The Minimal detectable change (MDC) value was 5.8 (patient) and 2.3 (health professional) points. There was a floor, but no ceiling, effect. In summary, the Brazilian version of the QUIP-RS has high reliability and content validity.
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http://dx.doi.org/10.1038/s41531-020-0108-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7018811PMC
February 2020

A Balancing Act: The Immune System Supports Neurodegeneration and Neurogenesis.

Cell Mol Neurobiol 2020 Aug 24;40(6):967-989. Epub 2020 Jan 24.

Programa de Neurobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, RJ, 21949-902, Brazil.

Decapod crustaceans, like mammals, retain the ability to make new neurons throughout life. In mammals, immune cells are closely associated with stem cells that generate adult-born neurons. In crayfish, evidence suggests that immune cells (hemocytes) originating in the immune system travel to neurogenic regions and transform into neural progenitor cells. This nontraditional immune activity takes place continuously under normal physiological conditions, but little is known under pathological conditions (neurodegeneration). In this study, the immune system and its relationship with neurogenesis were investigated during neurodegeneration (unilateral antennular ablation) in adult crayfish. Our experiments show that after ablation (1) Proliferating cells decrease in neurogenic areas of the adult crayfish brain; (2) The immune response, but not neurogenesis, is ablation-side dependent; (3) Inducible nitric oxide synthase (iNOS) plays a crucial role in the neurogenic niche containing neural progenitors during the immune response; (4) Brain areas targeted by antennular projections respond acutely (15 min) to the lesion, increasing the number of local immune cells; (5) Immune cells are recruited to the area surrounding the ipsilateral neurogenic niche; and (6) The vasculature in the niche responds acutely by dilation and possibly also neovascularization. We conclude that immune cells are important in both neurodegeneration and neurogenesis by contributing in physiological conditions to the maintenance of the number of neural precursor cells in the neurogenic niche (neurogenesis), and in pathological conditions (neurodegeneration) by coordinating NO release and vascular responses associated with the neurogenic niche. Our data suggest that neural damage and recovery participate in a balance between these competing immune cell roles.
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http://dx.doi.org/10.1007/s10571-020-00787-5DOI Listing
August 2020

Oxidative stress: Noradrenaline as an integrator of responses in the neuroendocrine and immune systems of the ascidian Phallusia nigra.

Dev Comp Immunol 2020 04 13;105:103573. Epub 2019 Dec 13.

Laboratório Integrado de Biociências Translacionais, Instituto de Biodiversidade e Sustentabilidade, NUPEM, Universidade Federal do Rio de Janeiro, Av. São José Barreto, 764, Macaé, RJ, 27965-045, Brazil; Programa de Pós-Graduação em Produtos Bioativos e Biociências, Universidade Federal do Rio de Janeiro, Campus UFRJ, Av. Aluizio da Silva Gomes, 50, Macaé, RJ, 27930-560, Brazil. Electronic address:

Neurotransmitters play key roles in regulating the homeostasis of organisms in stressful environments. Noradrenaline (NA) is the main neurotransmitter known to modulate immunological parameters, and is important in the crosstalk between the neuroendocrine and immune systems. In this study, using the ascidian Phallusia nigra, we analyzed the level of catecholamines (CA) in the plasma after mechanical stress, and the effect of NA on the oxidative stress (OS) displayed by immune cells. We measured the concentration of reactive oxygen species (ROS), and analyzed whether α- and/or β-adrenoreceptors (ARs) are involved in ROS modulation, lipid peroxidation (LPO), antioxidant capacity against peroxyl radicals (ACAP), and activity of the enzymes catalase (CAT) and glutathione S transferase (GST) in immune cells after incubation with different concentrations of NA, with or without zymosan (ZnA) challenge. The results showed that NA reduced ROS production, even in immune cells challenged with ZnA, and that this modulation occurred through α-and β-ARs. ACAP levels showed different responses, depending on whether immune cells were challenged or not with ZnA, and also depending on the NA concentration: 1.0 μM NA increased ACAP levels, but 10.0 μM reduced ACAP levels. NA enhanced the activity of CAT and GST in ZnA-challenged and non-challenged immune cells, while 1.0 and 10.0 μM NA effectively reduced LPO. Taken together, these results show that NA can protect cells from ROS damage, decreasing ROS production and LPO, and enhancing ACAP as well as the activity of CAT and GST. The approach used here with this model contributes to understanding the relationship between the neuroendocrine and immune systems, revealing new effects of NA on OS regulation in ascidians.
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http://dx.doi.org/10.1016/j.dci.2019.103573DOI Listing
April 2020

Putative stem cells in the hemolymph and in the intestinal submucosa of the solitary ascidian .

Evodevo 2019 25;10:31. Epub 2019 Nov 25.

1Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, Trav. 14, São Paulo, SP 101 05508-090 Brazil.

Background: In various ascidian species, circulating stem cells have been documented to be involved in asexual reproduction and whole-body regeneration. Studies of these cell population(s) are mainly restricted to colonial species. Here, we investigate the occurrence of circulating stem cells in the solitary a member of the Styelidae, a family with at least two independent origins of coloniality.

Results: Using flow cytometry, we characterized a population of circulating putative stem cells (CPSCs) in and determined two gates likely enriched with CPSCs based on morphology and aldehyde dehydrogenase (ALDH) activity. We found an ALDH + cell population with low granularity, suggesting a stem-like state. In an attempt to uncover putative CPSCs niches in . , we performed a histological survey for hemoblast-like cells, followed by immunohistochemistry with stem cell and proliferation markers. The intestinal submucosa (IS) showed high cellular proliferation levels and high frequency of undifferentiated cells and histological and ultrastructural analyses revealed the presence of hemoblast aggregations in the IS suggesting a possible niche. Finally, we document the first ontogenetic appearance of distinct metamorphic circulatory mesenchyme cells, which precedes the emergence of juvenile hemocytes.

Conclusions: We find CPSCs in the hemolymph of the solitary ascidian , presumably involved in the regenerative capacity of this species. The presence of proliferating and undifferentiated mesenchymal cells suggests IS as a possible niche.
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http://dx.doi.org/10.1186/s13227-019-0144-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6876114PMC
November 2019

A subacute model of glaucoma based on limbal plexus cautery in pigmented rats.

Sci Rep 2019 11 8;9(1):16286. Epub 2019 Nov 8.

Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.

Glaucoma is a neurodegenerative disorder characterized by the progressive functional impairment and degeneration of the retinal ganglion cells (RGCs) and their axons, and is the leading cause of irreversible blindness worldwide. Current management of glaucoma is based on reduction of high intraocular pressure (IOP), one of its most consistent risk factors, but the disease proceeds in almost half of the patients despite such treatments. Several experimental models of glaucoma have been developed in rodents, most of which present shortcomings such as high surgical invasiveness, slow learning curves, damage to the transparency of the optic media which prevents adequate functional assessment, and variable results. Here we describe a novel and simple method to induce ocular hypertension in pigmented rats, based on low-temperature cauterization of the whole circumference of the limbal vascular plexus, a major component of aqueous humor drainage and easily accessible for surgical procedures. This simple, low-cost and efficient method produced a reproducible subacute ocular hypertension with full clinical recovery, followed by a steady loss of retinal ganglion cells and optic axons, accompanied by functional changes detected both by electrophysiological and behavioral methods.
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http://dx.doi.org/10.1038/s41598-019-52500-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6841973PMC
November 2019

A role for gangliosides and β1-integrin in the motility of olfactory ensheathing glia.

J Anat 2019 11 2;235(5):977-983. Epub 2019 Aug 2.

Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.

Olfactory ensheathing glia (OEG) are found in the olfactory mucosa, nerve and bulb, and provide in vivo ensheathment for the unmyelinated olfactory axons within the central and peripheral nervous system domains. OEG cells are able to migrate long distances within the neuropil of the central nervous system. Because gangliosides such as 9-O-acetyl GD3 have crucial regulatory roles in neuronal migration during development, we analyzed whether OEG in organotypical cultures are revealed by anti-9-O-acetyl GD3 and/or gangliosides are recognized by the A2B5 antibody (G-A2B5), and whether these gangliosides are involved in OEG migration. Our results showed that all OEG migrating out of a section of olfactory bulb onto a laminin substrate bound to the 9-O-acetyl GD3 and A2B5 antibodies, and that 2',3'-cyclic nucleotide phosphodiesterase (CNPase) colocalized with 9-O-acetyl GD3 and with G-A2B5. Additionally, we showed that the immune blockade of 9-O-acetyl GD3 or G-A2B5 reduced the migration of OEG on laminin, and that 9-O-acetyl GD3 and G-A2B5 colocalized with the β1-integrin subunit. We also confirmed the phenotype of in-vitro-grown OEG cells derived from adult rats, showing that they express CNPase, and also α-smooth muscle actin, which is not expressed by Schwann cells. Our data showed that the gangliosides 9-O-acetyl GD3 and G-A2B5 participate in the migratory activity of OEG cells, and that the β1-integrin subunit colocalizes with these gangliosides. These results suggest a new role for β1-integrin and gangliosides in the polarized migration of OEG cells, and provide new information on the molecules controlling OEG motility and behavior.
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http://dx.doi.org/10.1111/joa.13057DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6794200PMC
November 2019

The Neurotropic Parasite Toxoplasma gondii Induces Sustained Neuroinflammation with Microvascular Dysfunction in Infected Mice.

Am J Pathol 2018 11 17;188(11):2674-2687. Epub 2018 Aug 17.

Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address:

Toxoplasmosis is one of the leading parasitic diseases worldwide. Some data suggest that chronic acquired toxoplasmosis could be linked to behavioral alterations in humans. The parasite infects neurons, forming immunologically silent cysts. Cerebral microcirculation homeostasis is determinant to brain functions, and pathologic states can alter capillarity or blood perfusion, leading to neurodegeneration and cognitive deficits. Albino mice were infected with Toxoplasma gondii (ME49 strain) and analyzed after 10, 40, and 180 days. Infected mice presented decreased cerebral blood flow at 10 and 40 days post infection (dpi), which were restored at 180 dpi, as shown by laser speckle contrast imaging. Intravital microscopy demonstrated that infection led to significant capillary rarefaction, accompanied by neuroinflammation, with microglial activation and increased numbers of rolling and adherent leukocytes to the wall of cerebral capillaries. Acetylcholine-induced vasodilation was altered at all time points, and blood brain barrier permeability was evident in infected animals at 40 dpi. Infection reduced angiogenesis, with a decreased number of isolectin B4-stained blood vessels and a decrease in length and branching of laminin-stained capillaries. Sulfadiazine reduced parasite load and partially repaired microvascular damages. We conclude that T. gondii latent infection causes a harmful insult in the brain, promoting neuroinflammation and microcirculatory dysfunction in the brain, with decreased angiogenesis and can contribute to a neurodegenerative process.
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http://dx.doi.org/10.1016/j.ajpath.2018.07.007DOI Listing
November 2018

Acute exposure to water-soluble fractions of marine diesel oil: Evaluation of apoptosis and oxidative stress in an ascidian.

Chemosphere 2018 Nov 30;211:308-315. Epub 2018 Jul 30.

Laboratório Integrado de Morfologia, Núcleo em Ecologia e Desenvolvimento Sócio Ambiental de Macaé, NUPEM, Universidade Federal do Rio de Janeiro, Campus UFRJ, Macaé, RJ, Brazil; Programa de Pós-graduação em Ciências Ambientais e Conservação, NUPEM, UFRJ, Macaé, RJ, Brazil. Electronic address:

To understand the mechanisms involved in organisms' responses to toxicity from oil pollution, we studied the effect of acute exposure (24 h) to the marine water-soluble fraction of diesel oil (WFDO) on the ascidian Styela plicata. We evaluated the mortality and behavior by means of the siphon reflex, and the response of blood cells (hemocytes) contained in the pharynx, by means of the production of nitric oxide (NO) and reactive oxygen species (ROS), in addition to the activity of the antioxidant enzyme catalase (CAT). We also correlated oxidative stress with the activation of apoptotic pathways. No mortality occurred 24 h after the ascidians were exposed to 5% and 10% marine WFDO; however, the siphon reflex, a behavioral test based on the time that the animals took to close their siphons, increased. We also observed an inflammatory response, as estimated by the increase in the number of hemocytes in the pharynx. NO and ROS production and CAT activity were reduced, whereas caspase-3, a signaling molecule involved in apoptosis, was activated. This suggests that in ascidians acutely exposed to oil, another mechanism can occur in addition to oxidative stress. Another possibility is that WFDO may directly interact with cellular macromolecules and activate caspase-3, independently of generating oxidative stress. The results showed that components of diesel oil affected a marine organism, which showed reduced ROS production in the pharynx cells, including hemocytes, and activation of apoptotic pathways.
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http://dx.doi.org/10.1016/j.chemosphere.2018.07.138DOI Listing
November 2018

Neuroprotective effects of erythropoietin on rat retinas subjected to oligemia.

Clinics (Sao Paulo) 2018 19;73:e161. Epub 2018 Apr 19.

Programa de Neurobiologia, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BR.

Objectives: Erythropoietin may have neuroprotective potential after ischemia of the central nervous system. Here, we conducted a study to characterize the protective effects of erythropoietin on retinal ganglion cells and gliotic reactions in an experimentally induced oligemia model.

Methods: Rats were subjected to global oligemia by bilateral common carotid artery occlusion and then received either vehicle or erythropoietin via intravitreal injection after 48 h; they were euthanized one week after the injection. The densities of retinal ganglion cells and contents of glial fibrillary acidic protein (astrocytes/Müller cells) and cluster of differentiation 68 clone ED1 (microglia/macrophages), assessed by fluorescence intensity, were evaluated in frozen retinal sections by immunofluorescence and epifluorescence microscopy.

Results: Retinal ganglion cells were nearly undetectable one week after oligemia compared with the sham controls; however, these cells were partially preserved in erythropoietin-treated retinas. The contents of glial fibrillary acidic protein and cluster of differentiation 68 clone ED1, markers for reactive gliosis, were significantly higher in retinas after bilateral common carotid artery occlusion than those in both sham and erythropoietin-treated retinas.

Conclusions: The number of partially preserved retinal ganglion cells in the erythropoietin-treated group suggests that erythropoietin exerts a neuroprotective effect on oligemic/ischemic retinas. This effect could be related to the down-modulation of glial reactivity, usually observed in hypoxic conditions, clinically observed during glaucoma or retinal artery occlusion conditions. Therefore, glial reactivity may enhance neurodegeneration in hypoxic conditions, like normal-tension glaucoma and retinal ischemia, and erythropoietin is thus a candidate to be clinically applied after the detection of decreased retinal blood flow.
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http://dx.doi.org/10.6061/clinics/2018/e161DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5890171PMC
September 2018

Nitric-oxide generation induced by metals plays a role in their accumulation by Phallusia nigra hemocytes.

Mar Pollut Bull 2017 Nov 2;124(1):441-448. Epub 2017 Aug 2.

Laboratório de Neurobiologia Comparativa e do Desenvolvimento, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, UFRJ, Rio de Janeiro, RJ, Brazil.

Ascidians are good monitors for assessing water quality, since they filter large volumes of water; however, little is known about how xenobiotics, including metals, can affect ascidian hemocytes. Metals can be either toxic or beneficial to health, inducing many different responses. The response mechanism depends on the class of metals to which organisms are exposed: essential, nonessential, and borderline. To analyze the influence of metals from different classes on the protective mechanisms of an ascidian, we investigated the production of nitric oxide (NO) after exposure to various concentrations of Mg, Mn and Pb over different time periods. We also determined the amounts of each metal in the hemocytes. Our results indicated that especially Pb could stimulate NO production. Although Pb induced the highest NO production, cell viability was not severely altered in all Pb concentrations and time periods. Ascidians might serve as biomonitor for Pb, since their vanadocytes accumulate Pb.
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http://dx.doi.org/10.1016/j.marpolbul.2017.06.043DOI Listing
November 2017

Catecholamines are produced by ascidian immune cells: The involvement of PKA and PKC in the adrenergic signaling pathway.

Brain Behav Immun 2017 Mar 12;61:289-296. Epub 2017 Jan 12.

Laboratório Integrado de Morfologia, Núcleo em Ecologia e Desenvolvimento Sócio Ambiental de Macaé - NUPEM, Universidade Federal do Rio de Janeiro, Campus UFRJ-Macaé, RJ, Brazil; Pós-Graduação em Produtos Bioativos e Biociências, Universidade Federal do Rio de Janeiro, Campus UFRJ-Macaé, Macaé, RJ, Brazil. Electronic address:

The stress response is a complex mechanism, which includes changes in the immune system to enable organisms to maintain homeostasis. The neurohormones dopamine, noradrenaline (NA) and adrenalin are responsible for the physiological modulations that occur during acute stress. In the present study, we analyzed the effects of NA on the immune system specific to nitric-oxide (NO) production by subpopulations of immune cells (hemocytes) of the ascidian Phallusia nigra. We also investigated the capability of immune cells to produce catecholamine (CA). Finally, we tested the involvement of protein kinase A (PKA) and C (PKC) in the NA downstream signaling pathway. The results revealed that NA can reduce NO production by P. nigra hemocytes threefold, and that signet-ring cells, univacuolar refractile granulocytes and morula cells are the cell types most involved in this event. A challenge effected with Zymosan A induced CA production, and co-incubation with both inhibitors of the second messengers PKA and PKC revealed the involvement of these molecules in the adrenergic pathway of P. nigra hemocytes. Taken together, these results suggest that NO production can be down-regulated by NA through α- and β-adrenoceptors via the second messengers PKA and PKC.
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http://dx.doi.org/10.1016/j.bbi.2017.01.002DOI Listing
March 2017

Streptococcus pneumoniae resists intracellular killing by olfactory ensheathing cells but not by microglia.

Sci Rep 2016 11 9;6:36813. Epub 2016 Nov 9.

Laboratório Translacional em Fisiologia Molecular, Centro de Cirurgia Experimental, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.

Olfactory ensheathing cells (OECs) are a type of specialized glial cell currently considered as having a double function in the nervous system: one regenerative, and another immune. Streptococcus pneumoniae is a major agent of severe infections in humans, including meningitis. It is commonly found in the nasopharynx of asymptomatic carriers, and, under certain still unknown conditions, can invade the brain. We evaluated whether pneumococcal cells recovered from lysed OECs and microglia are able to survive by manipulating the host cell activation. An intracellular-survival assay of S. pneumoniae in OECs showed a significant number of bacterial CFU recovered after 3 h of infection. In contrast, microglia assays resulted in a reduced number of CFU. Electron-microscopy analysis revealed a large number of pneumococci with apparently intact morphology. However, microglia cells showed endocytic vesicles containing only bacterial cell debris. Infection of OEC cultures resulted in continuous NF-κB activation. The IFN-γ-induced increase of iNOS expression was reversed in infected OECs. OECs are susceptible to S. pneumoniae infection, which can suppress their cytotoxic mechanisms in order to survive. We suggest that, in contrast to microglia, OECs might serve as safe targets for pneumococci, providing a more stable environment for evasion of the immune system.
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http://dx.doi.org/10.1038/srep36813DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5101813PMC
November 2016

Developmental effects of exposure to ultraviolet B radiation on the freshwater prawn Macrobrachium olfersi: Mitochondria as a target of environmental UVB radiation.

Ecotoxicol Environ Saf 2016 Oct 23;132:279-87. Epub 2016 Jun 23.

Departamento de Biologia Celular, Embriologia e Genética, Universidade Federal de Santa Catarina, Brazil.

In South America, increased UVB radiation has become an important environmental issue that is potentially threatening aquatic ecosystems. Considering that species exhibit different degrees of sensitivity to UVB radiation and that embryos are more sensitive than organisms at later life stages, the aim of this study was to characterize the effects of UVB radiation on subcellular compartments of embryos of the freshwater prawn Macrobrachium olfersi. This species lives and reproduces in clear and shallow waters, where UV radiation can fully penetrates. Embryos were irradiated with a UVB 6W lamp for 30min and examined after 1h, 12h, 24h and 48h of exposure. The irradiance of the UVB used simulates the UV radiation that embryos receive in the natural environment. The subcellular compartment most affected by the UVB radiation was the mitochondria, which exhibited a circular shape, a decrease in mitochondrial cristae, rupture of membranes and a morphology compatible with fission. These impairments were observed simultaneously with increased ROS production, just after 1h of UVB exposure. Thus, we investigated proteins related to mitochondrial fission (Drp-1) and fusion (Mfn-1), which are essential to cell maintenance. We found a significant increase in Drp-1 expression at all analyzed time-points and a significant decrease in Mfn-1 expression only after 24h of UVB exposure. Additionally, a decrease in embryonic cell viability was verified via the mitochondrial integrity assay. To conclude, we observed important mitochondrial dysfunctions against the environmental stress caused by UVB radiation. Moreover, the cellular responses found are critical and should not be disregarded, because they impact embryos that can potentially compromise the aquatic ecosystems.
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http://dx.doi.org/10.1016/j.ecoenv.2016.06.018DOI Listing
October 2016

Neurotrophic factors in Parkinson's disease are regulated by exercise: Evidence-based practice.

J Neurol Sci 2016 Apr 10;363:5-15. Epub 2016 Feb 10.

Laboratório de Neurobiologia Comparativa e do Desenvolvimento, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil; Programa de Pós-Graduação em Educação Física, Universidade Federal do Rio de Janeiro, Brazil. Electronic address:

We carried out a qualitative review of the literature on the influence of forced or voluntary exercise in Parkinson's Disease (PD)-induced animals, to better understand neural mechanisms and the role of neurotrophic factors (NFs) involved in the improvement of motor behavior. A few studies indicated that forced or voluntary exercise may promote neuroprotection, through upregulation of NF expression, against toxicity of drugs that simulate PD. Forced training, such as treadmill exercise and forced-limb use, adopted in most studies, in addition to voluntary exercise on a running wheel are suitable methods for NFs upregulation.
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http://dx.doi.org/10.1016/j.jns.2016.02.017DOI Listing
April 2016

Effects of hypoxia and reoxygenation on the antioxidant defense system of the locomotor muscle of the crab Neohelice granulata (Decapoda, Varunidae).

J Comp Physiol B 2016 07 19;186(5):569-79. Epub 2016 Mar 19.

Programa de Pós-Graduação em Ciências Fisiológicas, Fisiologia Animal Comparada, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, FURG, Av. Itália, Km 8, Rio Grande, RS, CEP 96203-900, Brazil.

Crustaceans often occur in areas with variations in oxygen and experience situations known as hypoxia and reoxygenation. Consequences of such situations are increased levels of reactive oxygen species. To avoid oxidative damage intertidal crabs appear to possess an efficient antioxidant defense system (ADS). However, to date, studies have not addressed the strategies that are adopted by the crabs when exposed to hypoxia/reoxygenation cycles. Towards this end we evaluated the ADS and the role of melatonin as an antioxidant in the locomotor muscle of the crab Neohelice granulata under conditions of severe hypoxia and reoxygenation. Total antioxidant capacity against peroxyl radicals and the enzymes superoxide dismutase, catalase, glutathione peroxidase (GPx), and glutathione-S-transferase as well as the key enzyme of glutathione synthesis, glutamate cysteine ligase (GCL), were evaluated. Furthermore, GSH, GSH/GSSG index as well as hemolymph and cellular melatonin levels were evaluated. During hypoxia, increased GPx and GCL activity and decreased GSH and mitochondrial melatonin levels were observed, but during reoxygenation catalase activity increased and cytosolic melatonin levels decreased. It appears that the ADS in the locomotor muscle of N. granulata exert a modulating effect when being confronted with hypoxia and reoxygenation to avoid oxidative stress. During hypoxia, the ADS appear to target GPX activity as well as GSH and mitochondrial melatonin. During reoxygenation, however, evidence suggests that catalase and cytosolic melatonin are involved in the recovery of the locomotor muscle from oxidative damage and the suppression of further damage.
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http://dx.doi.org/10.1007/s00360-016-0976-2DOI Listing
July 2016

Increased p53 and decreased p21 accompany apoptosis induced by ultraviolet radiation in the nervous system of a crustacean.

Aquat Toxicol 2016 Apr 12;173:1-8. Epub 2016 Jan 12.

Programa de Pós Graduação em Ciências Biológicas-Fisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro-UFRJ, Rio de Janeiro, RJ 21941-590, Brazil. Electronic address:

Ultraviolet (UV) radiation can produce biological damage, leading the cell to apoptosis by the p53 pathway. This study evaluated some molecular markers of the apoptosis pathway induced by UVA, UVB and UVA+ UVB (Solar Simulator, SIM) in environmental doses, during five consecutive days of exposure, in the brain of the crab Ucides cordatus. We evaluated the central nervous system (CNS) by immunoblotting the content of proteins p53, p21, phosphorylated AKT, BDNF, GDNF, activated caspase-3 (C3) and phosphohistone H3 (PH3); and by immunohistochemical tests of the cells labeled for PH3 and C3. After the fifth day of exposure, UVB radiation and SIM increased the protein content of p53, increasing the content of AKT and, somehow, blocking p21, increasing the content of activated caspase-3, which led the cells to apoptosis. The signs of death affected the increase in neurotrophins, such as BDNF and GDNF, stimulating the apoptotic cascade of events. Immunohistochemical assays and immunoblotting showed that apoptosis was present in the brains of all UV groups, while the number of mitotic cells in the same groups decreased. In conclusion, environmental doses of UV can cause apoptosis by increasing p53 and decreasing p21, revealing an UV-damage pathway for U. cordatus.
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http://dx.doi.org/10.1016/j.aquatox.2015.12.025DOI Listing
April 2016

Culture of neural cells of the eyestalk of a mangrove crab is optimized on poly-L-ornithine substrate.

Cytotechnology 2016 Oct 16;68(5):2193-206. Epub 2016 Jan 16.

Programa de Pós Graduação em Ciências Morfológicas, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.

Although there is a considerable demand for cell culture protocols from invertebrates for both basic and applied research, few attempts have been made to culture neural cells of crustaceans. We describe an in vitro method that permits the proliferation, growth and characterization of neural cells from the visual system of an adult decapod crustacean. We explain the coating of the culture plates with different adhesive substrates, and the adaptation of the medium to maintain viable neural cells for up to 7 days. Scanning electron microscopy allowed us to monitor the conditioned culture medium to assess cell morphology and cell damage. We quantified cells in the different substrates and performed statistical analyses. Of the most commonly used substrates, poly-L-ornithine was found to be the best for maintaining neural cells for 7 days. We characterized glial cells and neurons, and observed cell proliferation using immunocytochemical reactions with specific markers. This protocol was designed to aid in conducting investigations of adult crustacean neural cells in culture. We believe that an advantage of this method is the potential for adaptation to neural cells from other arthropods and even other groups of invertebrates.
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http://dx.doi.org/10.1007/s10616-015-9942-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5023563PMC
October 2016

Light-mediated DNA Repair Prevents UVB-induced Cell Cycle Arrest in Embryos of the Crustacean Macrobrachium olfersi.

Photochem Photobiol 2015 Jul-Aug;91(4):869-78. Epub 2015 May 4.

Departamento de Biologia Celular, Embriologia e Genética, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil.

High levels of ultraviolet-B (UVB) radiation can negatively affect aquatic animals. Macrobrachium olfersi is a prawn that lives in clear freshwaters and during the breeding season, females carry eggs in an external brood pouch. Therefore, we hypothesize that eggs are also exposed to environmental UVB radiation. The aim of this study was to investigate whether UVB radiation induces DNA damage and compromises cell cycle in embryos of M. olfersi. In laboratory, UVB irradiance (310 mW. cm(-2) ) that embryos receive in the natural environment was simulated. After irradiation, embryos were kept under different light conditions in order to recognize the presence of cell repair. UVB radiation induces DNA damage, specifically thymine dimers. After 48 h of UVB exposure, a significant decrease in the level of these dimers was observed in embryos kept under visible light while it remained constant in the dark. Moreover, under visible light and darkness, a decrease in proliferation was observed after 48 h of irradiation. An increase in PCNA expression and decrease in p53 expression were observed after, respectively, 1 and 48 h of exposure. Our results showed that UVB radiation disturbs the cell cycle and induces DNA damage in M. olfersi embryos. However, under visible light these embryos showed successful DNA repair.
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http://dx.doi.org/10.1111/php.12457DOI Listing
December 2015

Antioxidant activity stimulated by ultraviolet radiation in the nervous system of a crustacean.

Aquat Toxicol 2015 Mar 15;160:151-62. Epub 2015 Jan 15.

Programa de Pós Graduação em Ciências Biológicas-Fisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro-UFRJ, Rio de Janeiro, RJ 21941-590, Brazil. Electronic address:

Ultraviolet (UV) radiation can produce biological damage, principally oxidative stress, by increasing the production of reactive oxygen species (ROS). This study evaluated biochemical impairments related to the oxidative stress induced by UVA, UVB and UVA+UVB (solar simulator-SIM) in environmental doses, during five consecutive days of exposure, in the brain and eyestalk of the crab Ucides cordatus. We evaluated these regions by sampling on the 1st, 3rd and 5th days of UV exposure for lipid peroxidation (LPO), antioxidant capacity against the peroxyl radical (ACAP), and the activities of catalase (CAT), glutathione peroxidase (GPX) and glutathione-S-transferase (GST). Immunohistochemical and immunoblotting assays were performed for anti-activated-caspase 3 in the brains. After the first day of exposure, LPO increased in the eyestalks and brains of the UV-exposed animals; ACAP, and CAT, GPX and GST activities also increased in the brains. On the third day, the LPO values in the eyestalk remained high in the UV-exposed groups, while ACAP decreased in the brain and eyestalk and CAT activity remained high in all irradiated groups in both regions. On the fifth day, LPO decreased in the eyestalk and brain of the UV-exposed groups. These results may have been a consequence of the antioxidant defense system (ADS) activity, since CAT activity was high in both regions, ACAP was high in the eyestalks of the SIM group, and GPX activity remained high in the eyestalks of the UVA and UVB groups. Immunohistochemical assays and immunoblotting showed that there was apoptosis in the brains of the UV-exposed crabs. In conclusion, environmental doses of UV can cause oxidative damage to the CNS cells, including apoptosis.
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http://dx.doi.org/10.1016/j.aquatox.2015.01.008DOI Listing
March 2015

Melatonin as a signaling molecule for metabolism regulation in response to hypoxia in the crab Neohelice granulata.

Int J Mol Sci 2014 Dec 4;15(12):22405-20. Epub 2014 Dec 4.

Programa de Pós-Graduação em Ciências Fisiológicas-Fisiologia Animal Comparada, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande (FURG), 96201-300 Rio Grande, Brazil.

Melatonin has been identified in a variety of crustacean species, but its function is not as well understood as in vertebrates. The present study investigates whether melatonin has an effect on crustacean hyperglycemic hormone (CHH) gene expression, oxygen consumption (VO2) and circulating glucose and lactate levels, in response to different dissolved-oxygen concentrations, in the crab Neohelice granulata, as well as whether these possible effects are eyestalk- or receptor-dependent. Melatonin decreased CHH expression in crabs exposed for 45 min to 6 (2, 200 or 20,000 pmol·crab-1) or 2 mgO2·L-1 (200 pmol·crab-1). Since luzindole (200 nmol·crab-1) did not significantly (p > 0.05) alter the melatonin effect, its action does not seem to be mediated by vertebrate-typical MT1 and MT2 receptors. Melatonin (200 pmol·crab-1) increased the levels of glucose and lactate in crabs exposed to 6 mgO2·L-1, and luzindole (200 nmol·crab-1) decreased this effect, indicating that melatonin receptors are involved in hyperglycemia and lactemia. Melatonin showed no effect on VO2. Interestingly, in vitro incubation of eyestalk ganglia for 45 min at 0.7 mgO2·L-1 significantly (p < 0.05) increased melatonin production in this organ. In addition, injections of melatonin significantly increased the levels of circulating melatonin in crabs exposed for 45 min to 6 (200 or 20,000 pmol·crab-1), 2 (200 and 20,000 pmol·crab-1) and 0.7 (200 or 20,000 pmol·crab-1) mgO2·L-1. Therefore, melatonin seems to have an effect on the metabolism of N. granulata. This molecule inhibited the gene expression of CHH and caused an eyestalk- and receptor-dependent hyperglycemia, which suggests that melatonin may have a signaling role in metabolic regulation in this crab.
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http://dx.doi.org/10.3390/ijms151222405DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4284716PMC
December 2014

3-acetylpyridine-induced degeneration in the adult ascidian neural complex: Reactive and regenerative changes in glia and blood cells.

Dev Neurobiol 2015 Aug 11;75(8):877-93. Epub 2014 Dec 11.

Laboratório Integrado de Morfologia, Núcleo em Ecologia e Desenvolvimento Sócio Ambiental de Macaé, NUPEM, Universidade Federal do Rio de Janeiro, UFRJ, Macaé, RJ, Brazil.

Ascidians are interesting neurobiological models because of their evolutionary position as a sister-group of vertebrates and the high regenerative capacity of their central nervous system (CNS). We investigated the degeneration and regeneration of the cerebral ganglion complex of the ascidian Styela plicata following injection of the niacinamide antagonist 3-acetylpyridine (3AP), described as targeting the CNS of several vertebrates. For the analysis and establishment of a new model in ascidians, the ganglion complex was dissected and prepared for transmission electron microscopy (TEM), routine light microscopy (LM), immunohistochemistry and Western blotting, 1 or 10 days after injection of 3AP. The siphon stimulation test (SST) was used to quantify the functional response. One day after the injection of 3AP, CNS degeneration and recruitment of a non-neural cell type to the site of injury was observed by both TEM and LM. Furthermore, weaker immunohistochemical reactions for astrocytic glial fibrillary acidic protein (GFAP) and neuronal βIII-tubulin were observed. In contrast, the expression of caspase-3, a protein involved in the apoptotic pathway, and the glycoprotein CD34, a marker for hematopoietic stem cells, increased. Ten days after the injection of 3AP, the expression of markers tended toward the original condition. The SST revealed attenuation and subsequent recovery of the reflexes from 1 to 10 days after 3AP. Therefore, we have developed a new method to study ascidian neural degeneration and regeneration, and identified the decreased expression of GFAP and recruitment of blood stem cells to the damaged ganglion as reasons for the success of neuroregeneration in ascidians.
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http://dx.doi.org/10.1002/dneu.22255DOI Listing
August 2015

Evidence of involvement of the mannose receptor in the internalization of Streptococcus pneumoniae by Schwann cells.

BMC Microbiol 2014 Aug 2;14:211. Epub 2014 Aug 2.

Faculdade de Medicina, Centro de Cirurgia Experimental, Laboratório Translacional em Fisiologia Molecular, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.

Background: The ability of S. pneumoniae to generate infections depends on the restrictions imposed by the host's immunity, in order to prevent the bacterium from spreading from the nasopharynx to other tissues, such as the brain. Some authors claim that strains of S. pneumoniae, which fail to survive in the bloodstream, can enter the brain directly from the nasal cavity by axonal transport through the olfactory and/or trigeminal nerves. However, from the immunological point of view, glial cells are far more responsive to bacterial infections than are neurons. This hypothesis is consistent with several recent reports showing that bacteria can infect glial cells from the olfactory bulb and trigeminal ganglia. Since our group previously demonstrated that Schwann cells (SCs) express a functional and appropriately regulated mannose receptor (MR), we decided to test whether SCs are involved in the internalization of S. pneumoniae via MR.

Results: Immediately after the interaction step, as well as 3 h later, the percentage of association was approximately 56.5%, decreasing to 47.2% and 40.8% after 12 and 24 h, respectively. Competition assays by adding a 100-fold excess of mannan prior to the S. pneumoniae infection reduced the number of infected cells at 3 and 24 h. A cytochemistry assay with Man/BSA-FITC binding was performed in order to verify a possible overlap between mannosylated ligands and internalized bacteria. Incubation of the SCs with Man/BSA-FITC resulted in a large number of intracellular S. pneumoniae, with nearly complete loss of the capsule. Moreover, the anti-pneumococcal antiserum staining colocalized with the internalized man/BSA-FITC, suggesting that both markers are present within the same endocytic compartment of the SC.

Conclusions: Our data offer novel evidence that SCs could be essential for pneumococcal cells to escape phagocytosis and killing by innate immune cells. On the other hand, the results also support the idea that SCs are immunocompetent cells of the PNS that can mediate an efficient immune response against pathogens via MR.
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http://dx.doi.org/10.1186/s12866-014-0211-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4236529PMC
August 2014

Selective stimulatory action of olfactory ensheathing glia-conditioned medium on oligodendroglial differentiation, with additional reference to signaling mechanisms.

Biochem Biophys Res Commun 2014 Jul 20;449(3):338-43. Epub 2014 May 20.

Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil; Programa de Pós-Graduação em Ciências Biológicas (Fisiologia), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil. Electronic address:

We examined the effects of conditioned medium from olfactory ensheathing glia (OEGCM) on the differentiation of oligodendrocytes in mixed cultures of early postnatal hippocampi. Differentiation was judged from the numerical density (ND) of cells immunoreactive to 2'3' cyclic nucleotide 3'phosphodiesterase (CNPase) and O4 antibodies. NDs increased according to inverted-U dose-response curves, particularly for CNPase+ cells (9-fold at optimal dilution) and these changes were blocked by inhibitors of ERK1, p38-MAPK, and PI3K. Our results raise the possibility that OEG secreted factor(s) may counteract demyelination induced by trauma, neurodegenerative diseases, and advanced age, and should stimulate novel methods to deliver these factors and/or potentiating chemicals.
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http://dx.doi.org/10.1016/j.bbrc.2014.05.051DOI Listing
July 2014

Vascular endothelial growth factor-like and its receptor in a crustacean optic ganglia: a role in neuronal differentiation?

Biochem Biophys Res Commun 2014 May 4;447(2):299-303. Epub 2014 Apr 4.

Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil; Programa de Pós-Graduação em Ciências Morfológicas, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil; Programa de Pós-Graduação em Ciências Biológicas (Fisiologia), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, 21949-902 Rio de Janeiro, Brazil. Electronic address:

The neural system appears before the vascular system in the phylogenetic tree. During evolution, vascular system generation takes advantage of the pre-existing vascular endothelial growth factor (VEGF) in order to form its networks. Nevertheless, the role of VEGF in neuronal and glial cells is not yet completely understood. In order to support the hypothesis of a neural role for VEGF, we searched for VEGF- and VEGF receptor (VEGFR)-like immunoreactivities (immunohisto/cytochemistry and Western blotting) in the eyestalk of the invertebrate Ucides cordatus (Crustacea, Brachyura, Ucididae). Our results showed that both neurons and glial cells expressed VEGF-immunoreactivity, and that VEGFR was evidenced in neural cells. This is the first report about the VEGF/VEGFR-like immunoreactivities in the nervous tissue of a crustacean, and enables U. cordatus to be included in the repertoire of animal models used for ascertaining the role of VEGF in the nervous system.
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http://dx.doi.org/10.1016/j.bbrc.2014.03.137DOI Listing
May 2014

Regulation of nitric-oxide production in hemocytes of the ascidian Phallusia nigra.

Nitric Oxide 2014 Apr 2;38:26-36. Epub 2014 Mar 2.

Laboratório de Neurobiologia Comparativa e do Desenvolvimento, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro - UFRJ, Rio de Janeiro, RJ, Brazil. Electronic address:

Nitric oxide (NO) production in ascidians is related to immune responses of blood cells, and also to events such as egg fertilization and notochord regression. However, the signaling pathway for NO generation has been little investigated in this animal model. The present contribution identifies the cells involved in NO production and provides new information about a pathway for NO signaling. We were able to identify eight types of blood cells in the hemolymph of the ascidian Phallusia nigra, of which signet ring cells, univacuolar refractile granulocytes, and morula cells were involved in NO production. Zymosan A and lipopolysaccharide (LPS) enhanced NO production by blood cells, and the compound N-nitro-L-arginine-methyl ester (L-NAME) reduced NO production. Finally, the application of protein kinase A (PKA) and protein kinase C (PKC) inhibitors revealed that these molecules participate, together with NFκB, in the regulation of NO production by blood cells of P. nigra. This is the first report to show that PKA and PKC are involved in a signaling pathway that leads to NO production in ascidian blood cells.
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http://dx.doi.org/10.1016/j.niox.2014.02.007DOI Listing
April 2014

The crustacean central nervous system in focus: subacute neurodegeneration induces a specific innate immune response.

PLoS One 2013 20;8(11):e80896. Epub 2013 Nov 20.

Programa de Neurobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil ; Programa de Pós-Graduação em Morfologia, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.

To date nothing is known about the subacute phase of neurodegeneration following injury in invertebrates. Among few clues available are the results published by our group reporting hemocytes and activated glial cells at chronic and acute phases of the lesion. In vertebrates, glial activation and recruitment of immunological cells are crucial events during neurodegeneration. Here, we aimed to study the subacute stage of neurodegeneration in the crab Ucides cordatus, investigating the cellular/molecular strategy employed 48 hours following ablation of the protocerebral tract (PCT). We also explored the expression of nitric oxide (NO) and histamine in the PCT during this phase of neurodegeneration. Three immune cellular features which seem to characterize the subacute phase of neurodegeneration were revealed by: 1) the recruitment of granulocytes and secondarily of hyalinocytes to the lesion site (inducible NO synthase- and histamine-positive cells); 2) the attraction of a larger number of cells than observed in the acute phase; 3) the presence of activated glial cells as shown by the round shaped nuclei and increased expression of glial fibrillary acidic protein. We suggest that molecules released from granulocytes in the acute phase attract the hyalinocytes thus moving the degeneration process to the subacute phase. The importance of our study resides in the characterization of cellular and biochemical strategies peculiar to the subacute stage of the neurodegeneration in invertebrates. Such events are worth studying in crustaceans because in invertebrates this issue may be addressed with less interference from complex strategies resulting from the acquired immune system.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0080896PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3835822PMC
December 2014

The mannose receptor is expressed by olfactory ensheathing cells in the rat olfactory bulb.

J Neurosci Res 2013 Dec 16;91(12):1572-80. Epub 2013 Sep 16.

Instituto de Biofísica Carlos Chagas Filho, Laboratory of Comparative and Developmental Neurobiology, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.

Complex carbohydrate structures are essential molecules of infectious bacteria, parasites, and host cells and are involved in cell signaling associated with immune responses, glycoprotein homeostasis, and cell migration. The uptake of mannose-tailed glycans is usually carried out by professional phagocytes to trigger MHC class I- and MHC class II-restricted antigen presentation or, alternatively, to end inflammation. We have detected the mannose receptor (MR) in cultured olfactory ensheathing cells (OECs), so we investigated by flow cytometry whether recently dissociated cells of the olfactory bulb (OB) nerve fiber layer (ONL) could bind a mannosylated ligand (fluorescein conjugate of mannosyl bovine serum albumin; Man/BSA-FITC) in a specific manner. In addition, we estimated the relative proportion of ONL OECs, microglia, and astrocytes, tagged by 2'3'-cyclic nucleotide 3'-phosphodiesterase (CNPase), by the B4 isolectin of Griffonia simplicifonia (IB4), and by glial fibrillary acidic protein (GFAP), respectively, that were Man/BSA-FITC(+) . We also determined by histochemistry and/or immunohistochemistry whether Man/BSA-FITC or an anti-MR antibody (anti-C-terminal MR peptide; anti-cMR) labeled OECs and/or parenchymal microglia. In addition, we confirmed by Western blot with the K1K2 (against the entire MR molecule) antibody that a band of about 180 kDA is expressed in the OB. Our findings are compatible with a prospective sentinel role of OECs against pathogens of the upper airways and/or damage-associated glycidic patterns as well as with homeostasis of OB mannosylated glycoproteins.
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http://dx.doi.org/10.1002/jnr.23285DOI Listing
December 2013