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Astrocytes represent the most abundant cell type in the brain, where they play critical roles in synaptic transmission, cognition, and behavior. Recent discoveries show astrocytes are involved in synaptic dysfunction during Alzheimer's disease (AD). AD patients have imbalanced cholesterol metabolism, demonstrated by high levels of side-chain oxidized cholesterol known as 27-hydroxycholesterol (27-OH). Evidence from our laboratory has shown that elevated 27-OH can abolish synaptic connectivity during neuromaturation, but its effect on astrocyte function is currently unclear. Our results suggest that elevated 27-OH decreases the astrocyte function in vivo in Cyp27Tg, a mouse model of brain oxysterol imbalance. Here, we report a downregulation of glutamate transporters in the hippocampus of CYP27Tg mice together with increased GFAP. GLT-1 downregulation was also observed when WT mice were fed with high-cholesterol diets. To study the relationship between astrocytes and neurons, we have developed a 3D co-culture system that allows all the cell types from mice embryos to differentiate in vitro. We report that our 3D co-cultures reproduce the effects of 27-OH observed in 2D neurons and in vivo. Moreover, we found novel degenerative effects in astrocytes that do not appear in 2D cultures, together with the downregulation of glutamate transporters GLT-1 and GLAST. We propose that this transporter dysregulation leads to neuronal hyperexcitability and synaptic dysfunction based on the effects of 27-OH on astrocytes. Taken together, these results report a new mechanism linking oxysterol imbalance in the brain and synaptic dysfunction through effects on astrocyte function.
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Agricultural workers have an increased risk of musculoskeletal disorders, mainly due to the manual nature of the work. This study assesses the level of physical well-being in pepper cultivation workers in Almería (Spain). The objective was to analyze pepper cultivation tasks performed in the Almería-type greenhouse, using the OWAS (Ovako Working Posture Assessment System) and RULA (Rapid Upper Limb Assessment) methods. The OWAS results showed a normal posture percentage of 53 %, a medium risk of 30 %, a high risk of 16 %, and a very high risk of 1 %. The body areas most affected were the back and legs. The RULA assessment found high risk/action levels, with 50 % of the postures corresponding to level 3, 35 % to level 4, and 15 % to level 2. Improvements are therefore proposed; these include: redesigning tasks, mechanization, training, team development, and improving the workers' physical condition. The OWAS and RULA data may have overestimated the results, as workers do not appear to be limited in performing tasks and do not normally request sick leave.
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This paper shows the prevalence of psychosocial risks for workers in the greenhouse construction industry in south-eastern Spain. Method: The assessment of the workers' psychosocial risks was carried out through simple random sampling, which uses a questionnaire containing 13 variables characterizing the companies, 14 variables characterizing the workers, and 15 questions proposed by the Mini Psychosocial Factors (MPFs) risk assessment method. A descriptive analysis and multiple correspondence analysis were performed on the sample data. Results: Greenhouse construction businesses in south-eastern Spain can generally be classified as small companies with an average annual turnover below EUR 2.0 million (69.3%), an average of 22.8 workers with an average age of 39.84 years old, most of whom are married, with an average of 1.76 children. The prevalence of workers at high risk was 2.9%, while 45.1% were at medium-high risk. Of the 12 psychosocial factors assessed using the MPF method, 7 of them presented a high level of worker risk: Mobbing (3.2%), Relationships (1.6%), Recognition (1.6%), Autonomy (12.9%), Emotional (8.0%), Control (4.8%), and Demands (3.2%). Lastly, the variables were grouped into four clusters, showing that larger companies are correlated with a medium (workers over 40 years of age or less than 25 years of age) to high (workers under 25 years of age) risk level in several of the psychosocial factors assessed for workers who are Spanish nationals, while in smaller companies, the workers are usually middle aged (between 25 and 40 years old) and from Eastern Europe or Africa, presenting either a low or high level of risk depending on the psychosocial factors and tasks performed. Impact of the results: The study reveals a lack of prevention management regarding psychosocial risks. Therefore, it is necessary to carry out new prevention programmes that optimise the psychosocial conditions of the workers, involving the workers, employers, and other social agents.
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Indústria da Construção , Saúde Ocupacional , Adulto , África , Criança , Europa Oriental , Humanos , Pessoa de Meia-Idade , Prevalência , Espanha/epidemiologiaRESUMO
Alterations in brain cholesterol homeostasis in midlife are correlated with a higher risk of developing Alzheimer's disease (AD). However, global cholesterol-lowering therapies have yielded mixed results when it comes to slowing down or preventing cognitive decline in AD. We used the transgenic mouse model Cyp27Tg, with systemically high levels of 27-hydroxycholesterol (27-OH) to examine long-term potentiation (LTP) in the hippocampal CA1 region, combined with dendritic spine reconstruction of CA1 pyramidal neurons to detect morphological and functional synaptic alterations induced by 27-OH high levels. Our results show that elevated 27-OH levels lead to enhanced LTP in the Schaffer collateral-CA1 synapses. This increase is correlated with abnormally large dendritic spines in the stratum radiatum. Using immunohistochemistry for synaptopodin (actin-binding protein involved in the recruitment of the spine apparatus), we found a significantly higher density of synaptopodin-positive puncta in CA1 in Cyp27Tg mice. We hypothesize that high 27-OH levels alter synaptic potentiation and could lead to dysfunction of fine-tuned processing of information in hippocampal circuits resulting in cognitive impairment. We suggest that these alterations could be detrimental for synaptic function and cognition later in life, representing a potential mechanism by which hypercholesterolemia could lead to alterations in memory function in neurodegenerative diseases.
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Hipocampo/metabolismo , Hidroxicolesteróis/metabolismo , Plasticidade Neuronal/fisiologia , Doença de Alzheimer/metabolismo , Doença de Alzheimer/fisiopatologia , Animais , Região CA1 Hipocampal/metabolismo , Região CA1 Hipocampal/fisiologia , Disfunção Cognitiva/prevenção & controle , Espinhas Dendríticas/fisiologia , Modelos Animais de Doenças , Humanos , Potenciação de Longa Duração/fisiologia , Masculino , Camundongos , Camundongos Transgênicos , Proteínas dos Microfilamentos/metabolismo , Células Piramidais/fisiologia , Sinapses/fisiologia , Transmissão Sináptica/fisiologiaRESUMO
Surgical interventions rapidly trigger a cascade of molecular, cellular, and neural signaling responses that ultimately reach remote organs, including the brain. Using a mouse model of orthopedic surgery, we have previously demonstrated hippocampal metabolic, structural, and functional changes associated with cognitive impairment. However, the nature of the underlying signals responsible for such periphery-to-brain communication remains hitherto elusive. Here we present the first exploratory study that tests the hypothesis of extracellular vesicles (EVs) as potential mediators carrying information from the injured tissue to the distal organs including the brain. The primary goal was to investigate whether the cargo of circulating EVs after surgery can undergo quantitative changes that could potentially trigger phenotypic modifications in the target tissues. EVs were isolated from the serum of the mice subjected to a tibia surgery after 6, 24, and 72 h, and the proteome and miRNAome were investigated using mass spectrometry and RNA-seq approaches. We found substantial differential expression of proteins and miRNAs starting at 6 h post-surgery and peaking at 24 h. Interestingly, one of the up-regulated proteins at 24 h was α-synuclein, a pathogenic hallmark of certain neurodegenerative syndromes. Analysis of miRNA target mRNA and corresponding biological pathways indicate the potential of post-surgery EVs to modify the extracellular matrix of the recipient cells and regulate metabolic processes including fatty acid metabolism. We conclude that surgery alters the cargo of circulating EVs in the blood, and our results suggest EVs as potential systemic signal carriers mediating remote effects of surgery on the brain.
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Biomarcadores , Vesículas Extracelulares/metabolismo , Ferimentos e Lesões/metabolismo , Animais , Fracionamento Químico , Cromatografia Líquida , Modelos Animais de Doenças , Suscetibilidade a Doenças , Vesículas Extracelulares/ultraestrutura , Camundongos , MicroRNAs/genética , Proteoma , Proteômica/métodos , RNA Mensageiro/genética , Procedimentos Cirúrgicos Operatórios/efeitos adversos , Espectrometria de Massas em Tandem , Ferimentos e Lesões/sangue , Ferimentos e Lesões/etiologiaRESUMO
A decrease in synaptic plasticity and/or a change in excitation/inhibition balance have been suggested as mechanisms underlying major depression disorder. However, given the crucial role of astrocytes in balancing synaptic function, particular attention should be given to the contribution of astrocytes in these mechanisms, especially since previous findings show that astrocytes are affected and exhibit reactive-like features in depression. Moreover, it has been shown that reactive astrocytes increase the synthesis and release of GABA, contributing significantly to tonic GABA inhibition. In this study we found decreased plasticity and increased tonic GABA inhibition in the prelimbic area in acute slices from the medial prefrontal cortex in the Flinders Sensitive Line (FSL) rat model of depression. The tonic inhibition can be reduced by either blocking astrocytic intracellular Ca2+ signaling or by reducing astrocytic GABA through inhibition of the synthesizing enzyme MAO-B with Selegiline. Blocking GABA synthesis also restores the impaired synaptic plasticity in the FSL prefrontal cortex, providing a new antidepressant mechanism of Selegiline.
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Astrócitos/metabolismo , Depressão/fisiopatologia , Plasticidade Neuronal , Córtex Pré-Frontal/fisiopatologia , Ácido gama-Aminobutírico/metabolismo , Animais , Astrócitos/efeitos dos fármacos , Atrofia , Modelos Animais de Doenças , Potenciação de Longa Duração/efeitos dos fármacos , Masculino , Plasticidade Neuronal/efeitos dos fármacos , Ratos Sprague-Dawley , Receptores de GABA/metabolismo , Selegilina/farmacologiaRESUMO
NEW FINDINGS: What is the central question of this study? Are carotid bodies (CBs) modulated by the damage-associated molecular patterns (DAMPs) and humoral factors of aseptic tissue injury? What are the main findings and their importance? DAMPs (HMGB1, S100 A8/A9) and blood plasma from rats subjected to tibia surgery, a model of aseptic injury, stimulate the release of neurotransmitters (ATP, dopamine) and TNF-α from ex vivo rat CBs. All-thiol HMGB1 mediates upregulation of immune-related biological pathways. These data suggest regulation of CB function by endogenous mediators of innate immunity. ABSTRACT: The glomus cells of carotid bodies (CBs) are the primary sensors of arterial partial O2 and CO2 tensions and moreover serve as multimodal receptors responding also to other stimuli, such as pathogen-associated molecular patterns (PAMPs) produced by acute infection. Modulation of CB function by excessive amounts of these immunomodulators is suggested to be associated with a detrimental hyperinflammatory state. We have hypothesized that yet another class of immunomodulators, endogenous danger-associated molecular patterns (DAMPs), released upon aseptic tissue injury and recognized by the same pathogen recognition receptors as PAMPs, might modulate the CB activity in a fashion similar to PAMPs. We have tested this hypothesis by exposing rat CBs to various DAMPs, such as HMGB1 (all-thiol and disulfide forms) and S100 A8/A9 in a series of ex vivo experiments that demonstrated the release of dopamine and ATP, neurotransmitters known to mediate CB homeostatic responses. We observed a similar response after incubating CBs with conditioned blood plasma obtained from the rats subjected to tibia surgery, a model of aseptic injury. In addition, we have investigated global gene expression in the rat CB using an RNA sequencing approach. Differential gene expression analysis showed all-thiol HMGB1-driven upregulation of a number of prominent pro-inflammatory markers including Il1α and Il1ß. Interestingly, conditioned plasma had a more profound effect on the CB transcriptome resulting in inhibition rather than activation of the immune-related pathways. These data are the first to suggest potential modulation of CB function by endogenous mediators of innate immunity.
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Alarminas/metabolismo , Corpo Carotídeo/metabolismo , Neurotransmissores/metabolismo , Ferimentos e Lesões/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Calgranulina A , Calgranulina B , Dopamina/metabolismo , Expressão Gênica , Proteína HMGB1 , Masculino , Ratos , Ratos Sprague-Dawley , Tíbia/cirurgiaRESUMO
The objective of this study was to reveal RULA method applications in terms of the knowledge, country, year and journal categories. The search was performed using the "Web of Science Core Collection". The period from 1993 to April 2019 was selected. Eight hundred nine results were obtained, of which 226 were used. The largest number of publications was determined to be in the fields of industry and health and social assistance, which coincides with the OWAS and Standardized Nordic Questionnaire methods. By country, the USA stands out for its greater number of research studies and categories that are encompassed. By date, 2016 was the year when more studies were carried out, again coinciding with the Standardized Nordic Questionnaire. By journal, "Work-A Journal of Prevention Assessment and Rehabilitation" is highlighted, as it is for the REBA method as well. It was concluded that RULA can be applied to workers in different fields, usually in combination with other methods, while technological advancement provides benefits for its application.
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Bibliometria , Doenças Musculoesqueléticas/epidemiologia , Doenças Profissionais/epidemiologia , Medição de Risco/métodos , Ergonomia , Humanos , Indústrias/estatística & dados numéricos , Doenças Musculoesqueléticas/etiologia , Doenças Musculoesqueléticas/prevenção & controle , Doenças Profissionais/etiologia , Doenças Profissionais/prevenção & controle , Fatores de RiscoRESUMO
The objective of this work is to review literature, worldwide, in which the Rapid Entire Body Assessment (REBA) ergonomic assessment method was applied and count the number of times that REBA was applied together with other methods and subsequent incidence. The database used was the "Web of Science-Core Collection". Only scientific articles and bibliographic reviews were included, analysing a total of 314 documents and selecting only 91. The use of the REBA method is indicated in terms of knowledge, country, year and journal sectors. It was most used in the knowledge areas of "Manufacturing" (24.18%), "Agriculture, forestry and fishing" (21.98%) and in "Other activities" (19.78%). One of the benefits of REBA is that it evaluates different body parts: upper limbs (arm, forearm and wrist), lower extremities, trunk and neck. It is a useful method to identify the forced postures adopted by workers to thus develop improvement measures if necessary. It is concluded that REBA method use has increased over the last decade, probably due to the digitization of knowledge. It is almost always applied in combination with other methods, and its use can be a positive indicator of company sustainability.
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Ergonomia , Doenças Musculoesqueléticas , Doenças Profissionais , Criança , Feminino , Humanos , Índia , Doenças Musculoesqueléticas/diagnóstico , Doenças Profissionais/diagnóstico , Reprodutibilidade dos TestesRESUMO
In the present work, the results are presented for the characterization of work risk prevention in the Guatemalan construction industry. This characterization has been carried out using a simple random sampling technique, employing a questionnaire that was structured into 3 groups of variables: 1. General company data; 2. Prevention and management activities regarding health and safety in the company and on the worksite; and 3. Health and safety in the contractor companies. Following the sampling phase, the data were introduced in a database format, and a preliminary analysis was performed on the studied variables, followed by a descriptive analysis and a multiple correspondence analysis. The main findings of the study emphasize that companies in the Guatemalan construction sector are characterized as dedicating most of their activity (52.0%) indistinctly between civil engineering work, building construction and other specialized construction, mainly working as contractors (47.5%). These are "medium-sized" companies, employing an average of 81.1 on-site workers, having an average of 6.8 on-site work crews, and grossing an average turnover of 1.29 million euros annually. Likewise, it found that the larger construction companies adopt better prevention and management measures for worksite health and safety the larger companies are correlated with a high awareness of experiencing worksite accidents, while medium-sized companies have medium-level awareness. Companies with fewer workers manage workplace risk prevention worse, with low accident risk awareness. This correlation between these indicative variables of company size and workplace risk management and prevention is clearly reflected in the four company "clusters" that have been identified as having homogenous characteristics using the multiple correspondence analysis technique. Companies in the Guatemalan construction sector should make a greater effort to improve manager and worker training regarding workplace risk prevention to increase the effectiveness of company prevention management.
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Indústria da Construção/estatística & dados numéricos , Conhecimentos, Atitudes e Prática em Saúde , Saúde Ocupacional/estatística & dados numéricos , Local de Trabalho/estatística & dados numéricos , Humanos , Gestão de Riscos , Empresa de Pequeno Porte , Inquéritos e QuestionáriosRESUMO
Immune-related events in the periphery can remotely affect brain function, contributing to neurodegenerative processes and cognitive decline. In mice, peripheral surgery induces a systemic inflammatory response associated with changes in hippocampal synaptic plasticity and transient cognitive decline, however, the underlying mechanisms remain unknown. Here we investigated the effect of peripheral surgery on neuronal-glial function within hippocampal neuronal circuits of relevance to cognitive processing in male mice at 6, 24, and 72 h postsurgery. At 6 h we detect the proinflammatory cytokine IL-6 in the hippocampus, followed up by alterations in the mRNA and protein expression of astrocytic and neuronal proteins necessary for optimal energy supply to the brain and for the reuptake and recycling of glutamate in the synapse. Similarly, at 24 h postsurgery the mRNA expression of structural proteins (GFAP and AQP4) was compromised. At this time point, functional analysis in astrocytes revealed a decrease in resting calcium signaling. Examination of neuronal activity by whole-cell patch-clamp shows elevated levels of glutamatergic transmission and changes in AMPA receptor subunit composition at 72 h postsurgery. Finally, lactate, an essential energy substrate produced by astrocytes and critical for memory formation, decreases at 6 and 72 h after surgery. Based on temporal parallels with our previous studies, we propose that the previously reported cognitive decline observed at 72 h postsurgery in mice might be the consequence of temporal hippocampal metabolic, structural, and functional changes in astrocytes that lead to a disruption of the neuroglial metabolic coupling and consequently to a neuronal dysfunction.SIGNIFICANCE STATEMENT A growing body of evidence suggests that surgical trauma launches a systemic inflammatory response that reaches the brain and associates with immune activation and cognitive decline. Understanding the mechanisms by which immune-related events in the periphery can influence brain processes is essential for the development of therapies to prevent or treat postoperative cognitive dysfunction and other forms of cognitive decline related to immune-to-brain communication, such as Alzheimer's and Parkinson's diseases. Here we describe the temporal orchestration of a series of metabolic, structural, and functional changes after aseptic trauma in mice related to astrocytes and later in neurons that emphasize the role of astrocytes as key intermediaries between peripheral immune events, neuronal processing, and potentially cognition.
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Hipocampo/metabolismo , Neuroglia/metabolismo , Neuroimunomodulação/fisiologia , Neurônios/metabolismo , Osteotomia/efeitos adversos , Animais , Citocinas/biossíntese , Hipocampo/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos C57BLRESUMO
The prevention of musculoskeletal disorders (MSD) is very important in the world. Governments and companies are the most interested. The objective of the present work is to review the literature on the applications of the OWAS method in the diverse sectors or fields of knowledge and countries from its publication to March 2017. The use of OWAS method has been classified by categories of knowledge, by country and by year. The search was made by selecting only the main collection of the Web of Science. This was selected by the option "Advanced search" using the term OWAS (ts=OWAS) for the time period of 1900 to 2017. A total of 166 results were found, consisting of conference papers and articles in scientific journals. In conclusion, the OWAS has been applied mainly in two sectors: "Manufacturing industries" and "Healthcare and Social assistance activities". This method needs to be complemented with other indirect or direct methods. Also, whenever the OWAS has been used, whether individually or together with other methods, musculoskeletal disorders risks have been detected, this perhaps being an indicator to review the evaluation parameters because overestimating the risk.
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Doenças Musculoesqueléticas/prevenção & controle , Postura , Ergonomia , Feminino , Humanos , Masculino , Doenças Musculoesqueléticas/etiologia , Doenças Profissionais/etiologia , Doenças Profissionais/prevenção & controleRESUMO
Stress, such as social isolation, is a well-known risk factor for depression, most probably in combination with predisposing genetic factors. Physical exercise on the other hand, is depicted as a wonder-treatment that makes you healthier, happier and live longer. However, the published results on the effects of exercise are ambiguous, especially when it comes to neuropsychiatric disorders. Here we combine a paradigm of social isolation with a genetic rat model of depression, the Flinders Sensitive Line (FSL), already known to have glutamatergic synaptic alterations. Compared to group-housed FSL rats, we found that social isolation further affects synaptic plasticity and increases basal synaptic transmission in hippocampal CA1 pyramidal neurons. These functional synaptic alterations co-exist with changes in hippocampal protein expression levels: social isolation in FSL rats reduce expression of the glial glutamate transporter GLT-1, and increase expression of the GluA2 AMPA-receptor subunit. We further show that physical exercise in form of voluntary running prevents the stress-induced synaptic effects but do not restore the endogenous mechanisms of depression already present in the FSL rat.
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Depressão/fisiopatologia , Transportador 2 de Aminoácido Excitatório/metabolismo , Isolamento Social/psicologia , Sinapses/fisiologia , Animais , Comportamento Animal , Depressão/metabolismo , Modelos Animais de Doenças , Hipocampo/metabolismo , Masculino , Plasticidade Neuronal , Ratos , Corrida , Sinapses/metabolismo , Transmissão SinápticaRESUMO
The possibility that exposure to general anesthetics during early life results in long-term impairment of neural function attracted considerable interest over the past decade. Extensive laboratory data suggest that administration of these drugs during critical stages of central nervous system development can lead to cell death, impaired neurogenesis, and synaptic growth as well as cognitive deficits. These observations are corroborated by several recent human epidemiological studies arguing that such cognitive impairment might also occur in humans. Despite the potential public health importance of this issue, several important questions remain open. Amongst them, how the duration of anesthesia exposure impact on outcome is as yet not fully elucidated. To gain insight into this question, here we focused on the short- and long-term impact of a 30-min-long exposure to clinically relevant concentrations of sevoflurane in rat pups at 2 functionally distinct stages of the brain growth spurt. We show that this treatment paradigm induced developmental stage-dependent and brain region-specific acute but not lasting changes in dendritic spine densities. Electrophysiological recordings in hippocampal brain slices from adult animals exposed to anesthesia in the early postnatal period revealed larger paired-pulse facilitation but no changes in the long-term potentiation paradigm when compared with nonanesthetized controls. 5-bromo-2-deoxyuridine pulse and pulse-chase experiments demonstrated that neither proliferation nor differentiation and survival of hippocampal progenitors were affected by sevoflurane exposure. In addition, behavioral testing of short- and long-term memory showed no differences between control and sevoflurane-exposed animals. Overall, these results suggest that brief sevoflurane exposure during critical periods of early postnatal development, although it does not seem to exert major long-term effects on brain circuitry development, can induce subtle changes in synaptic plasticity and spine density of which the physiological significance remains to be determined.
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Anestésicos Inalatórios/toxicidade , Espinhas Dendríticas/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Éteres Metílicos/toxicidade , Plasticidade Neuronal/efeitos dos fármacos , Anestesia , Animais , Animais Recém-Nascidos , Hipocampo/patologia , Potenciação de Longa Duração/efeitos dos fármacos , Masculino , Ratos , Ratos Wistar , SevofluranoRESUMO
The role of developmental transcription factors in maintenance of neuronal properties and in disease remains poorly understood. Lmx1a and Lmx1b are key transcription factors required for the early specification of ventral midbrain dopamine (mDA) neurons. Here we show that conditional ablation of Lmx1a and Lmx1b after mDA neuron specification resulted in abnormalities that show striking resemblance to early cellular abnormalities seen in Parkinson's disease. We found that Lmx1b was required for the normal execution of the autophagic-lysosomal pathway and for the integrity of dopaminergic nerve terminals and long-term mDA neuronal survival. Notably, human LMX1B expression was decreased in mDA neurons in brain tissue affected by Parkinson's disease. Thus, these results reveal a sustained and essential requirement of Lmx1b for the function of midbrain mDA neurons and suggest that its dysfunction is associated with Parkinson's disease pathogenesis.
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Autofagia/genética , Dopamina/metabolismo , Proteínas com Homeodomínio LIM/metabolismo , Lisossomos/metabolismo , Doença de Parkinson/fisiopatologia , Fatores de Transcrição/metabolismo , Animais , Comportamento Animal , Monoaminas Biogênicas/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Neurônios Dopaminérgicos/fisiologia , Humanos , Proteínas com Homeodomínio LIM/genética , Camundongos , Camundongos Knockout , Doença de Parkinson/genética , Doença de Parkinson/psicologia , Fatores de Transcrição/genética , Fatores de Transcrição/fisiologiaRESUMO
Accumulating in vivo and ex vivo evidences show that humans suffering from depression have decreased hippocampal volume and altered spine density. Moreover, physical activity has an antidepressant effect in humans and in animal models, but to what extent physical activity can affect hippocampal volume and spine numbers in a model for depression is not known. In this study we analyzed whether physical activity affects hippocampal volume and spine density by analyzing a rodent genetic model of depression, Flinders Sensitive Line Rats (FSL), with Magnetic Resonance Imaging (MRI) and ex vivo Golgi staining. We found that physical activity in the form of voluntary wheel running during 5 weeks increased hippocampal volume. Moreover, runners also had larger numbers of thin spines in the dentate gyrus. Our findings support that voluntary wheel running, which is antidepressive in FSL rats, is associated with increased hippocampal volume and spine numbers.
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Hospitalization for major surgery or critical illness often associates with cognitive decline. Inflammation and dysregulation of the innate immune system can exert broad effects in the periphery and central nervous system (CNS), yet the mechanisms underlying memory impairment after surgery remain poorly understood and without effective therapy. Endogenous regulation of acute inflammation is providing novel approaches to treat several disease states including sepsis, pain, obesity and diabetes. Resolvins are potent endogenous lipid mediators biosynthesized during the resolution phase of acute inflammation that display immunoresolvent actions. Here, using a mouse model of surgery-induced cognitive decline we report that orthopedic surgery affects hippocampal neuronal-glial function, including synaptic transmission and plasticity. Systemic prophylaxis with aspirin-triggered resolvin D1 (AT-RvD1: 7S,8R,17R-trihydroxy-4Z,9E,11E,13Z,15E,19Z-docosahexaenoic acid, as little as 100 ng dose per mouse) improved memory decline following surgery and abolished signs of synaptic dysfunction. Moreover, delayed administration 24 h after surgery also attenuated signs of neuronal dysfunction postoperatively. AT-RvD1 also limited peripheral damage by modulating the release of systemic interleukin (IL)-6 and improved other clinical markers of tissue injury. Collectively, these results demonstrate a novel role of AT-RvD1 in modulating the proinflammatory milieu after aseptic injury and protecting the brain from neuroinflammation, synaptic dysfunction and cognitive decline. These findings provide novel and safer approaches to treat postoperative cognitive decline and potentially other forms of memory dysfunctions.
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Aspirina/farmacologia , Aspirina/uso terapêutico , Cognição/efeitos dos fármacos , Ácidos Docosa-Hexaenoicos/farmacologia , Ácidos Docosa-Hexaenoicos/uso terapêutico , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Eletrofisiologia , Imuno-Histoquímica , Técnicas In Vitro , Locomoção/efeitos dos fármacos , Potenciação de Longa Duração/efeitos dos fármacos , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/metabolismo , Masculino , Camundongos , Complicações Pós-Operatórias/prevenção & controle , Superóxidos/metabolismoRESUMO
Mood disorders, such as major depressive disorder (MDD), bipolar disorder and generalized anxiety disorder usually comprise mood related as well as cognitive symptoms and the interaction between these symptoms is still not clear. Most antidepressant drugs have a positive effect on mood but do not treat the cognitive dysfunctions or even aggravate the symptoms. In this review we will evaluate the association between mood and cognition in the context of mood disorders. In the first section we will summarize the brain circuits at the intersection between cognition and emotion, highlighting the role of the hippocampus. In the second section, we will survey the contribution of the glutamate and GABA systems in the pathophysiology of mood disorders, making an effort to understand the link between emotions and cognition and how novel therapeutic approaches deal with them. In the third section we will explore the monoamine involvement in the emotion/cognition duality in the context of mood disorders. Finally we will underline the role of synaptic plasticity and neurogenesis in depression. We consider that a broader knowledge about the integrative mechanisms involved in specific aspects of mood disorders is crucial in the development of more powerful and effective antidepressant drugs. This article is part of a Special Issue entitled: Brain Integration.
Assuntos
Sintomas Comportamentais/patologia , Transtornos Cognitivos/patologia , Hipocampo/fisiopatologia , Transtornos do Humor/patologia , Animais , Antidepressivos/uso terapêutico , Sintomas Comportamentais/tratamento farmacológico , Sintomas Comportamentais/metabolismo , Transtornos Cognitivos/tratamento farmacológico , Ácido Glutâmico/metabolismo , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Humanos , Transtornos do Humor/tratamento farmacológico , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/metabolismo , Córtex Pré-Frontal/patologia , Sinapses/metabolismo , Sinapses/patologia , Ácido gama-Aminobutírico/metabolismoRESUMO
The deficiency in the mitochondrial aspartate/glutamate transporter Aralar/AGC1 results in a loss of the malate-aspartate NADH shuttle in the brain neurons, hypomyelination, and additional defects in the brain metabolism. We studied the development of cortico/hippocampal local field potential (LFP) in Aralar/AGC1 knockout (KO) mice. Laminar profiles of LFP, evoked potentials, and unit activity were recorded under anesthesia in young (P15 to P22) Aralar-KO and control mice as well as control adults. While LFP power increased 3 to 7 times in both cortex and hippocampus of control animals during P15 to P22, the Aralar-KO specimens hardly progressed. The divergence was more pronounced in the CA3/hilus region. In parallel, spontaneous multiunit activity declined severely in KO mice. Postnatal growth of hippocampal-evoked potentials was delayed in KO mice, and indicated abnormal synaptic and spike electrogenesis and reduced output at P20 to P22. The lack of LFP development in KO mice was accompanied by the gradual appearance of epileptic activity in the CA3/hilus region that evolved to status epilepticus. Strikingly, CA3 bursts were poorly conducted to the CA1 field. We conclude that disturbed substrate supply to neuronal mitochondria impairs development of cortico-hippocampal LFPs. Aberrant neuronal electrogenesis and reduced neuron output may explain circuit dysfunction and phenotype deficiencies.
Assuntos
Sistema X-AG de Transporte de Aminoácidos/metabolismo , Hipocampo/crescimento & desenvolvimento , Hipocampo/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Sistema X-AG de Transporte de Aminoácidos/genética , Animais , Células Cultivadas , Feminino , Glutamato Descarboxilase/metabolismo , Hipocampo/citologia , Masculino , Camundongos , Camundongos Knockout , Mitocôndrias/genética , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/genética , Neurônios/metabolismoRESUMO
Spreading depression (SD), a wave of neuron activity related to migraine and the ischaemic penumbra, features a moving shell of extracellular negative potential shift (V(o)) whose generators are poorly understood. We investigated its subcellular correlates in the hippocampal CA1 in vivo by localizing the neuron domains that generate transmembrane current (I(m)) using field analysis, and the local changes of tissue resistivity, a major determinant of extracellular current flow. A large increase of tissue resistivity occurred in times and dendritic strata displaying large V(o), albeit with different rates. Typically, SD is composed of basal and apical dendritic components. The apical SD lasts much longer, while it becomes gradually restricted to a narrow dendritic region. Strikingly, pyramidal cells displayed a strong surge of inward current only when SD affected a small dendritic region. However, when the V(o) signal covered most of the main neuron axis, only smaller surges of inward current developed at the outer dendritic rims of a wide null current zone. Computational reconstruction showed that this effect was due to strong spatial cancellation of the inward and outward currents in SD-activated isopotential and shunted regions of individual neurons. Consequently, despite former accounts of large conductance increase, the net I(m) is small and the large DeltaV(o) amplitude mostly due to increased tissue resistivity. The particular subcellular evolution indicates an initial explosive opening of conductance along most of the pyramidal neuron followed by a wave-like centripetal closure towards the apical dendrites. The applicability of these mechanisms to SD in other brain regions is discussed.