RESUMO
Disease is a neurodegenerative disorder characterised by the progressive loss of dopaminergic cells of the substantia nigra pars compacta. Even though successful transplantation of dopamine-producing cells into the striatum exhibits favourable effects in animal models and clinical trials; transplanted cell survival is low. Since every transplant elicits an inflammatory response which can affect cell survival and differentiation, we aimed to study in vivo and in vitro the impact of the pro-inflammatory environment on human dopaminergic precursors. We first observed that transplanted human dopaminergic precursors into the striatum of immunosuppressed rats elicited an early and sustained activation of astroglial and microglial cells after 15 days' post-transplant. This long-lasting response was associated with Tumour necrosis factor alpha expression in microglial cells. In vitro, conditioned media from activated BV2 microglial cells increased cell death, decreased Tyrosine hydroxylase-positive cells and induced morphological alterations on human neural stem cells-derived dopaminergic precursors at two differentiation stages: 19 days and 28 days. Those effects were ameliorated by inhibition of Tumour necrosis factor alpha, a cytokine which was previously detected in vivo and in conditioned media from activated BV-2 cells. Our results suggest that a pro-inflammatory environment is sustained after transplantation under immunosuppression, providing a window of opportunity to modify this response to increase transplant survival and differentiation. In addition, our data show that the microglia-derived pro-inflammatory microenvironment has a negative impact on survival and differentiation of dopaminergic precursors. Finally, Tumour necrosis factor alpha plays a key role in these effects, suggesting that this cytokine could be an interesting target to increase the efficacy of human dopaminergic precursors transplantation in Parkinson's Disease.
Assuntos
Microglia , Fator de Necrose Tumoral alfa , Humanos , Animais , Ratos , Fator de Necrose Tumoral alfa/farmacologia , Meios de Cultivo Condicionados/farmacologia , Dopamina , Diferenciação Celular , CitocinasRESUMO
In Drosophila melanogaster, several Gal4 drivers are used to direct gene/RNAi expression to different dopaminergic neuronal clusters. We previously developed a fly model of Parkinson's disease, in which dopaminergic neurons had elevated cytosolic Ca2+ due to the expression of a Plasma Membrane Ca2+ ATPase (PMCA) RNAi under the thyroxine hydroxylase (TH)-Gal4 driver. Surprisingly, TH-Gal4>PMCARNAi flies died earlier compared to controls and showed swelling in the abdominal area. Flies expressing the PMCARNAi under other TH drivers also showed such swelling and shorter lifespan. Considering that TH-Gal4 is also expressed in the gut, we proposed to suppress the expression specifically in the nervous system, while maintaining the activation in the gut. Therefore, we expressed Gal80 under the direction of the panneuronal synaptobrevin (nSyb) promoter in the context of TH-Gal4. nSyb-Gal80; TH-Gal4>PMCARNAi flies showed the same reduction of survival as TH-Gal4>PMCARNAi flies, meaning that the phenotype of abdomen swelling and reduced survival could be due to the expression of the PMCARNAi in the gut. In perimortem stages TH-Gal4>PMCARNAi guts had alteration in the proventriculi and crops. The proventriculi appeared to lose cells and collapse on itself, and the crop increased its size several times with the appearance of cellular accumulations at its entrance. No altered expression or phenotype was observed in flies expressing PMCARNAi in the dopaminergic PAM cluster (PAM-Gal4>PMCARNAi). In this work we show the importance of checking the global expression of each promoter and the relevance of the inhibition of PMCA expression in the gut.
Assuntos
Proteínas de Drosophila , Drosophila melanogaster , Fatores de Transcrição , Tirosina 3-Mono-Oxigenase , Animais , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Membrana Celular/metabolismo , Neurônios Dopaminérgicos/metabolismo , Regulação para Baixo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Longevidade/genética , Fatores de Transcrição/genética , Tirosina 3-Mono-Oxigenase/genética , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
BACKGROUND: Inflammation in the Central Nervous System (CNS) is associated with blood brain barrier (BBB) breakdown during the early stages of Multiple Sclerosis (MS), indicating a facilitated entry of waves of inflammatory cells from the circulation to the CNS. In the progressive forms of MS, as the lesion becomes chronic, the inflammation remains trapped within the CNS compartment forming the slow evolving lesion, characterized by low inflammation and microglia activation at the lesions edges. The chronic expression of interleukin 1ß (IL-1ß) in the cortex induces BBB breakdown, demyelination, neurodegeneration, microglial/macrophage activation and impaired cognitive performance. The latter can be improved, as long as the BBB recovers and the lesion presents low inflammation. Here, we study the effects of peripheral inflammation on cortical central lesions after the restoration of the BBB, in order to elucidate the role of the peripheral inflammation on these lesions with intact BBB, as it occurs in the progressive forms of MS. MATERIALS AND METHODS: Cortical lesions and peripheral inflammation were induced by the chronic expression of IL-1ß using an adenovector. We performed histological, immunohistochemistry on brain tissue and behavioural analyses. RESULTS: The effects of the chronic expression of IL-1ß in the cortex resolved within 56 days. However, peripheral and sustained inflammation re-opened the BBB, allowing the reappearance of the neuroinflammatory processes within the cortical lesions, increased demyelination and neurodegeneration, and an increase of the behavioral symptoms, such as cognitive impairment and anxiety-like symptoms. CONCLUSIONS: The early treatment of peripheral inflammatory processes should be considered in order to protect the brain from exacerbation of the ongoing neurodegenerative process.
Assuntos
Barreira Hematoencefálica , Esclerose Múltipla , Encéfalo , Sistema Nervoso Central , Humanos , InflamaçãoRESUMO
The accumulation of Ca2+ and its subsequent increase in oxidative stress is proposed to be involved in selective dysfunctionality of dopaminergic neurons, the main cell type affected in Parkinson's disease. To test the in vivo impact of Ca2+ increment in dopaminergic neurons physiology, we downregulated the plasma membrane Ca2+ ATPase (PMCA), a pump that extrudes cytosolic Ca2+ , by expressing PMCARNAi in Drosophila melanogaster dopaminergic neurons. In these animals, we observed major locomotor alterations paralleled to higher cytosolic Ca2+ and increased levels of oxidative stress in mitochondria. Interestingly, although no overt degeneration of dopaminergic neurons was observed, evidences of neuronal dysfunctionality were detected such as increases in presynaptic vesicles in dopaminergic neurons and in the levels of dopamine in the brain, as well as presence of toxic effects when PMCA was downregulated in the eye. Moreover, reduced PMCA levels were found in a Drosophila model of Parkinson's disease, Parkin knock-out, expanding the functional relevance of PMCA reduction to other Parkinson's disease-related models. In all, we have generated a new model to study motor abnormalities caused by increments in Ca2+ that lead to augmented oxidative stress in a dopaminergic environment, added to a rise in synaptic vesicles and dopamine levels.
Assuntos
Doença de Parkinson , ATPases Transportadoras de Cálcio da Membrana Plasmática , Animais , Cálcio/metabolismo , Neurônios Dopaminérgicos/metabolismo , Regulação para Baixo , Drosophila melanogaster , ATPases Transportadoras de Cálcio da Membrana Plasmática/genética , ATPases Transportadoras de Cálcio da Membrana Plasmática/metabolismoRESUMO
Multiple sclerosis (MS) is a chronic, immune-mediated disease of the central nervous system (CNS) that affects both white and gray matter. Although it has been traditionally considered as a T cell mediated disease, the role of B cell in MS pathology has become a topic of great research interest. Cortical lesions, key feature of the progressive forms of MS, are involved in cognitive impairment and worsening of the patients' outcome. These lesions present pathognomonic hallmarks, such as: absence of blood-brain barrier (BBB) disruption, limited inflammatory events, reactive microglia, neurodegeneration, demyelination and meningeal inflammation. B cells located in the meninges, either as part of diffuse inflammation or as part of follicle-like structures, are strongly associated with cortical damage. The function of CD20-expressing B cells in MS is further highlighted by the success of specific therapies using anti-CD20 antibodies. The possible roles of B cells in pathology go beyond their ability to produce antibodies, as they also present antigens to T cells, secrete cytokines (both pathogenic and protective) within the CNS to modulate T and myeloid cell functions, and are involved in meningeal inflammation. Here, we will review the contributions of B cells to the pathogenesis of meningeal inflammation and cortical lesions in MS patients as well as in preclinical animal models.
Assuntos
Esclerose Múltipla , Animais , Linfócitos B , Substância Cinzenta , Humanos , Inflamação , Meninges , Modelos AnimaisRESUMO
Multiple sclerosis (MS) is a neurological disease characterized by neuroinflammation, demyelination and axonal degeneration along with loss of function in the central nervous system. For many years, research in MS has focused on the efficacy of pharmacological treatments. However, during the last years, many publications have been dedicated to the study of the efficacy of non-pharmacological strategies, such as physical exercise and cognitive training. Beneficial effects of the combination of both strategies on cognitive function have been described in both ageing adults and patients with neurodegenerative diseases, such as MS. The analysis of combining both physical and cognitive stimulation can be summarized by the environmental enrichment (EE) experiments, which are more suitable for animal models. EE refers to housing conditions consisting of exercise and cognitive and social stimulation. In this review, we will summarize the available studies that describe the influence of EE in both MS patients and MS animal models.
Assuntos
Encéfalo/fisiopatologia , Transtornos Cognitivos/reabilitação , Exercício Físico/fisiologia , Esclerose Múltipla/metabolismo , Esclerose Múltipla/reabilitação , Animais , Cognição/fisiologia , Humanos , Esclerose Múltipla/tratamento farmacológico , Doenças Neurodegenerativas/reabilitaçãoRESUMO
Multiple Sclerosis (MS) is a neuroinflammatory disease affecting white and grey matter, it is characterized by demyelination, axonal degeneration along with loss of motor, sensitive and cognitive functions. MS is a heterogeneous disease that displays different clinical courses: relapsing/remitting MS (RRMS), and MS progressive forms: primary progressive (PPMS) and secondary progressive (SPMS). Cortical damage in the progressive MS forms has considerable clinical relevance due to its association with cognitive impairment and disability progression in patients. One treatment is available for the progressive forms of the disease, but none are specific for cognitive deficits. We developed an animal model that reflects most of the characteristics of the cortical damage, such as cortical neuroinflammation, demyelination, neurodegeneration and meningeal inflammation, which was associated with cognitive impairment. Cognitive rehabilitation, exercise and social support have begun to be evaluated in patients and animal models of neurodegenerative diseases. Environmental enrichment (EE) provides exercise as well as cognitive and social stimulation. EE has been demonstrated to exert positive effects on cognitive domains, such as learning and memory, and improving anxiety-like symptoms. We proposed to study the effect of EE on peripherally stimulated cortical lesion induced by the long term expression of interleukin IL-1ß (IL-1ß) in adult rats. Here, we demonstrated that EE: 1) reduces the peripheral inflammatory response to the stimulus, 2) ameliorates cognitive deficits and anxiety-like symptoms, 3) modulates neurodegeneration, demyelination and glial activation, 4) regulates neuroinflammation by reducing the expression of pro-inflammatory cytokines and enhancing the expression of anti-inflammatory ones. Our findings correlate with the fact that EE housing could be considered an effective non- pharmacological therapeutic agent that can synergistically aid in the rehabilitation of the disease.
Assuntos
Disfunção Cognitiva/reabilitação , Esclerose Múltipla/psicologia , Esclerose Múltipla/reabilitação , Interação Social , Apoio Social , Animais , Cognição , Substância Cinzenta/metabolismo , Substância Cinzenta/patologia , Humanos , Inflamação/metabolismo , Inflamação/patologia , Inflamação/terapia , Masculino , Condicionamento Físico Animal , Ratos , Ratos WistarRESUMO
Multiple sclerosis (MS) is an inflammatory and neurodegenerative disease that involves an intricate interaction between the central nervous system and the immune system. Nevertheless, its etiology is still unknown. MS exhibits different clinical courses: recurrent episodes with remission periods ('relapsing-remitting') that can evolve to a 'secondary progressive' form or persistent progression from the onset of the disease ('primary progressive'). The discovery of an effective treatment and cure has been hampered due to the pathological and clinical heterogeneity of the disease. Historically, MS has been considered as a disease exclusively of white matter. However, patients with progressive forms of MS present with cortical lesions associated with meningeal inflammation along with physical and cognitive disabilities. The pathogenesis of the cortical lesions has not yet been fully described. Animal models that represent both the cortical and meningeal pathologies will be critical in addressing MS pathogenesis as well as the design of specific treatments. In this review, we will address the state-of-the-art diagnostic and therapeutic alternatives and the development of strategies to discover new therapeutic approaches, especially for the progressive forms.
Assuntos
Córtex Cerebral/patologia , Doenças Desmielinizantes/patologia , Esclerose Múltipla/patologia , Substância Branca/patologia , Animais , Progressão da Doença , Humanos , Inflamação/imunologia , Esclerose Múltipla/terapiaRESUMO
The specific roles of Notch in progressive adulthood neurodegenerative disorders have begun to be unraveled in recent years. A number of independent studies have shown significant increases of Notch expression in brains from patients at later stages of sporadic Alzheimer's disease (AD). However, the impact of Notch canonical signaling activation in the pathophysiology of AD is still elusive. To further investigate this issue, 2-month-old wild-type (WT) and hemizygous McGill-R-Thy1-APP rats (Tg(+/-)) were injected in CA1 with lentiviral particles (LVP) expressing the transcriptionally active fragment of Notch, known as Notch Intracellular Domain (NICD), (LVP-NICD), or control lentivirus particles (LVP-C). The Tg(+/-) rat model captures presymptomatic aspects of the AD pathology, including intraneuronal amyloid beta (Aß) accumulation and early cognitive deficits. Seven months after LVP administration, Morris water maze test was performed, and brains isolated for biochemical and histological analysis. Our results showed a learning impairment and a worsening of spatial memory in LVP-NICD- as compared to LVP-C-injected Tg(+/-) rats. In addition, immuno histochemistry, ELISA multiplex, Western blot, RT-qPCR, and 1H-NMR spectrometry of cerebrospinal fluid (CSF) indicated that chronic expression of NICD promoted hippocampal vessel thickening with accumulation of Aß in brain microvasculature, alteration of blood-brain barrier (BBB) permeability, and a decrease of CSF glucose levels. These findings suggest that, in the presence of early Aß pathology, expression of NICD may contribute to the development of microvascular abnormalities, altering glucose transport at the BBB with impact on early decline of spatial learning and memory.