Eleonora Kurtenbach - Academia.edu (original) (raw)

Papers by Eleonora Kurtenbach

Brain, behavior, and immunity, May 1, 2024

Frontiers in Pharmacology, Apr 21, 2023

Introduction: Sepsis is defined as a multifactorial debilitating condition with high risks of dea... more Introduction: Sepsis is defined as a multifactorial debilitating condition with high risks of death. The intense inflammatory response causes deleterious effects on the brain, a condition called sepsis-associated encephalopathy. Neuroinflammation or pathogen recognition are able to stress cells, resulting in ATP (Adenosine Triphosphate) release and P2X7 receptor activation, which is abundantly expressed in the brain. The P2X7 receptor contributes to chronic neurodegenerative and neuroinflammatory diseases; however, its function in long-term neurological impairment caused by sepsis remains unclear. Therefore, we sought to evaluate the effects of P2X7 receptor activation in neuroinflammatory and behavioral changes in sepsis-surviving mice. Methods: Sepsis was induced in wild-type (WT), P2X7 −/− , and BBG (Brilliant Blue G)-treated mice by cecal ligation and perforation (CLP). On the thirteenth day after the surgery, the cognitive function of mice was assessed using the novel recognition object and Water T-maze tests. Acetylcholinesterase (AChE) activity, microglial and astrocytic activation markers, and cytokine production were also evaluated. Results: Initially, we observed that both WT and P2X7 −/− sepsis-surviving mice showed memory impairment 13 days after surgery, once they did not differentiate between novel and familiar objects. Both groups of animals presented increased AChE activity in the hippocampus and cerebral cortex. However, the absence of P2X7 prevented partly this increase in the cerebral cortex. Likewise, P2X7 absence decreased ionized calcium-binding protein 1 (Iba −1) and glial fibrillary acidic protein (GFAP) upregulation in the cerebral cortex of sepsis-surviving animals.

FEBS Letters, Dec 4, 2003

Gene expression patterns in response to hydrostatic pressure were determined by whole genome micr... more Gene expression patterns in response to hydrostatic pressure were determined by whole genome microarray hybridization. Functional classi¢cation of the 274 genes a¡ected by pressure treatment of 200 MPa for 30 min revealed a stress response expression pro¢le. The majority of the s 2-fold upregulated genes were involved in stress defense and carbohydrate metabolism while most of the repressed ones were in cell cycle progression and protein synthesis categories. Furthermore, uncharacterized genes were among the 10 highest expressed sequences and represented 45% of the total upregulated genes. The results of this study revealed a hydrostatic pressure-speci¢c stress response pattern and suggested interesting information about the mechanisms involved in adaptation of cells to a high-pressure environment.

Biochemical Society Transactions, Feb 1, 1991

JCSM Clinical Reports, 2021

BackgroundThis study investigated the effects of methylmercury intoxication on mice skeletal musc... more BackgroundThis study investigated the effects of methylmercury intoxication on mice skeletal muscle subjected or not to progressive resistance training (RT).MethodsFour experimental groups were formed. Control and Con + RT received water and methylmercury (MeHg) and MeHg + RT groups received methylmercury (5 mg/kg/day), via gavage for 14 days. The Con + RT and MeHg + RT animals performed weighted ladder climbing RT, three times a week for 4 weeks. Animal muscle strength and gastrocnemius and soleus cross‐section area, fibrosis, myosin heavy chains (MyHCs), E3‐ligases MAFbx and MuRF1, 20S proteasome (P20S) and LC3‐II content were analysed. In addition, P20S chymotrypsin‐like activity was evaluated.ResultsResistance training protected MeHg + RT mice against strength loss but not against muscle atrophy. The latter appeared to be associated with MyHCs significant content reductions observed in the MeHg and MeHg + RT groups. In soleus muscle, there was an increase in E3‐ligases and P20S ...

Background: Sepsis is associated with high mortality rates ... more Background: Sepsis is associated with high mortality rates in intensive care units worldwide and represents a systemic inflammatory response to infection. P2X7 is an ionotropic purine receptor with known proinflammatory activity. Here, we investigated the role of the P2X7 receptor in sepsis induced by cecal ligation and puncture (CLP). Methods: Wild-type (WT) and P2X7KO (P2X7 null) mice were subjected to CLP and their survival was monitored for 7 days. Blood, peritoneal wash and lungs were collected 24 h after CLP and used to measure bacterial load, immune cell infiltration, nitric oxide (NO), cytokine levels, and peritoneal cell death and to assess lung injury. Results: P2X7KO mice showed significantly increased survival 7 days after CLP (30% compared to 60% in WT animals) accompanied by an overall attenuated inflammatory response, with decreased cell recruitment to the peritoneum, no or limited increases in the levels of NO and proinflammatory cytokines (IL-1β, IL-6, IL-12, IL-17, and IL-4), reduced peritoneal cell apoptosis, and less pronounced lung infiltration and morphological changes. Conclusions: Our data show the P2X7 receptor is required for the development of the inflammatory response associated with sepsis and support the notion that P2X7 receptor is a valid therapeutic target against inflammatory diseases.

O Espaco Ciencia Viva (ECV) e um museu interativo de ciencias localizado na Tijuca, onde criancas... more O Espaco Ciencia Viva (ECV) e um museu interativo de ciencias localizado na Tijuca, onde criancas, adolescentes e adultos “aprendem” Ciencias de forma divertida e dinâmica, em atividades baseadas na experimentacao. Atende escolas agendadas durante a semana, com participacao de mediadores de diferentes cursos de graduacao, e no ultimo sabado de cada mes recebe o publico geral com atividades tematicas. Em 2008, o Projeto Sangue Ciencia e Vida foi implantado no Museu em parceria com o HLA-UERJ, a UFRJ e o Hemorio. Neste periodo foram produzidos diversos materiais instrucionais e em 2014 foi instalado um laboratorio multidisciplinar capacitado para a execucao de experimentos mais elaborados, dentro das normas de Boas Praticas e Bioseguranca. Dentre estes, destacamos a pratica “Extracao de Medula Ossea” onde os mediadores do ECV provocam a curiosidade e o conhecimento dos visitantes sobre assuntos relacionados a doacao de medula ossea. Esta atividade e realizada apos uma incursao dos a...

O Museu Espaco Ciencia Viva e uma organizacao sem fins lucrativos e e o primeiro museu participat... more O Museu Espaco Ciencia Viva e uma organizacao sem fins lucrativos e e o primeiro museu participativo de Ciencias do Brasil. Fundado, em 1982, por um grupo de cientistas, pesquisadores e educadores interessados em tornar a Ciencia mais proxima do cidadao comum, o Espaco Ciencia Viva desenvolve acoes e atividades para um publico diversificado, prioritariamente de jovens e criancas. O projeto em questao tem como objetivo principal a divulgacao dos eventos oferecidos e dos projetos desenvolvidos pelo museu. Isso e proporcionado atraves da utilizacao de midias sociais (Facebook e Twitter) e de outras plataformas online (site proprio,http://www.cienciaviva.org.br). A intencao e manter um site informativo sobre assuntos relacionados ao cenario cientifico atual, com entrevistas, artigos e noticias. Paralelamente a isso, a utilizacao de redes sociais auxilia na divulgacao do material produzido e, principalmente, na divulgacao dos eventos realizados no museu. Consequentemente, essas pecas de ...

Journal of Biological Chemistry, 1990

Muscarinic acetylcholine receptors (mAChR) were purified from rat brain and labeled either with t... more Muscarinic acetylcholine receptors (mAChR) were purified from rat brain and labeled either with the site-directed affinity label [3H]propylbenzilylcholine mustard (PrBCM) or with the sulfhydryl-specific label [3H]N-ethylmaleimide (NEM), using a protocol designed to give selective incorporation of the label into disulfide-bonded cysteines. m1 mAChRs were purified from CHO-K1 cells stably expressing the cloned receptor sequence and labeled with [3H]PrBCM. The labeled receptors were cleaved with the lysine-specific protease Lys-C and, after fractionation of the products, subcleaved with cyanogen bromide. Two major CNBr cleavage products were found with a molecular mass of approximately 3.9 and approximately 2.4 kDa, labeled either by [3H]PrBCM or [3H]NEM. The results obtained from CNBr cleavage of purified forebrain receptors were consistent with those obtained from the purified cloned m1 mAChR. Edman degradation was applied to the CNBr peptides. The results were compatible with the attachment of the [3H]PrBCM label to a conserved aspartic acid residue in transmembrane helix 3 of the mAChR (corresponding to Asp-105, m1 sequence) and of [3H]NEM to a conserved cysteine residue (corresponding to Cys-98, m1 sequence). These results support the hypothesis that the cysteine residue participates in a disulfide bond on the extracellular surface of the mAChRs and related G-protein-coupled receptors, while the aspartic acid residue is involved in binding the positively charged headgroup of muscarinic antagonists.

Autoimmunity, 2018

Autoantibodies against the M2 subtype of muscarinic acetylcholine receptors with functional activ... more Autoantibodies against the M2 subtype of muscarinic acetylcholine receptors with functional activities have been found in the sera of patients with dilated cardiomyopathy (DCM), and the second extracellular loop has been established as the predominant epitope. However, it has been shown that the third intracellular loop is recognized by Chagas disease patients with severe cardiac dysfunction. In this work, BALB/c mice were immunized with plasmids encoding these two epitopes, and a control group received the empty plasmid (pcDNA3 vector). Serum from these DNA-immunized animals had elevated and persistent titres of antibodies against respective antigens. Heart echocardiography indicated diminished left ventricular wall thickness and reduced ejection fraction for both epitopeimmunized groups, and ergospirometry tests showed a significant decrease in the exercise time and oxygen consumption. Transfer of serum from these immunized mice into naïve recipients induced the same alterations in cardiac structure and function. Furthermore, electron microscopy analysis of donor-immunized animals revealed several ultrastructural alterations suggestive of autophagy and mitophagy, suggesting novel roles for these autoantibodies. Overall, greater functional and structural impairment was observed in the donor and recipient epitope groups, implicating the third intracellular loop epitope in the pathological effects for the first-time. Therefore, the corresponding peptides could be useful for autoimmune DCM diagnosis and targeted therapy.

Universidade Federal do Rio Grande do SulCiências BiológicasAgronomiaDepositad

Biochemical Society Transactions, 1991

Journal of Biological Chemistry

High intensity interval training (HIIT) is characterized by vigorous exercise with short rest int... more High intensity interval training (HIIT) is characterized by vigorous exercise with short rest intervals. Hydrogen peroxide (H 2 O 2) plays a key role in muscle adaptation. This study aimed to evaluate whether HIIT promotes similar H 2 O 2 formation via O 2 consumption (electron leakage) in three skeletal muscles with different twitch characteristics. Rats were assigned to two groups: sedentary (n=10) and HIIT (n=10, swimming training). We collected the tibialis anterior (TA-fast), gastrocnemius (GAST-fast/slow) and soleus (SOL-slow) muscles. The fibers were analyzed for mitochondrial respiration, H 2 O 2 production and citrate synthase (CS) activity. A multi-substrate (glycerol phosphate (G3P), pyruvate, malate, glutamate and succinate) approach was used to analyze the mitochondria in permeabilized fibers. Compared to the control group, oxygen flow coupled to ATP synthesis, complex I and complex II was higher in the TA of the HIIT group by 1.5-, 3.0-and 2.7-fold, respectively. In contrast, oxygen consumed by mitochondrial glycerol phosphate dehydrogenase (mGPdH) was 30% lower. Surprisingly, the oxygen flow coupled to ATP synthesis was 42% lower after HIIT in the SOL. Moreover, oxygen flow coupled to ATP synthesis and complex II was higher by 1.4-and 2.7-fold in the GAST of the HIIT group. After HIIT, CS activity increased 1.3-fold in the TA, and H 2 O 2 production was 1.3-fold higher in the TA at sites containing mGPdH. No significant differences in H 2 O 2 production were detected in the SOL. Surprisingly, HIIT increased H 2 O 2 production in the GAST via complex II, phosphorylation, oligomycin and antimycin by 1.6-, 1.8-, 2.2-, and 2.2-fold, respectively. Electron leakage was 3.3-fold higher in the TA with G3P and 1.8-fold higher in the GAST with multiple substrates. Unexpectedly, the HIIT protocol induced different respiration and electron leakage responses in different types of muscle.

Cellular and molecular biology (Noisy-le-Grand, France), 2004

Yeasts are unicellular organisms that are exposed to a highly variable environment, concerning th... more Yeasts are unicellular organisms that are exposed to a highly variable environment, concerning the availability of nutrients, temperature, pH, radiation, access to oxygen and, specially, water activity. Evolution has selected yeasts to tolerate, to a certain extent, these environmental stresses. High hydrostatic pressure (HHP) exerts a broad effect upon yeast cells, interfering with the cell membranes, cellular architecture and in processes ofpolymerisation and denaturation of proteins. Gene expression patterns in response to HHP revealed a stress response profile. The majority of the upregulated genes were involved in stress defence and carbohydrate metabolism while most of the repressed ones were in cell cycle progression and protein synthesis categories. In addition, in the present work it was seen that mild pressure induced cell cycle arrest and protection against severe stresses, such as high temperature, high pressure and ultra cold shock. Nevertheless, this protection was onl...

Frontiers in Immunology

Despite long-term sequelae of COVID-19 are emerging as a substantial public health concern, the m... more Despite long-term sequelae of COVID-19 are emerging as a substantial public health concern, the mechanism underlying these processes still unclear. Evidence demonstrates that SARS-CoV-2 Spike protein can reach different brain regions, irrespective of viral brain replication resulting in activation of pattern recognition receptors (PRRs) and neuroinflammation. Considering that microglia dysfunction, which is regulated by a whole array of purinergic receptors, may be a central event in COVID-19 neuropathology, we investigated the impact of SARS-CoV-2 Spike protein on microglial purinergic signaling. Here, we demonstrate that cultured microglial cells (BV2 line) exposed to Spike protein induce ATP secretion and upregulation of P2Y6, P2Y12, NTPDase2 and NTPDase3 transcripts. Also, immunocytochemistry analysis shows that spike protein increases the expression of P2X7, P2Y1, P2Y6, and P2Y12 in BV2 cells. Additional, hippocampal tissue of Spike infused animals (6,5ug/site, i.c.v.) presents...

A Física na Escola, May 24, 2024

Microscopy and Microanalysis, 2003