RESUMO
In humans, the pituitary gland is covered by a fibrous capsule and is considered a continuation of the meningeal sheath. However, in rodents some studies concluded that only the pars tuberalis (PT) and pars nervosa (PN) are enwrapped by the pia mater, while others showed that the whole gland is covered by this sheath. At PT the median eminence subarachnoid drains cerebrospinal fluid (CSF) to its cisternal system representing a pathway to the hypothalamus. In the present study we examined the rat pituitary capsule to elucidate its configuration, its physical interaction with the pituitary border and its relationship with the CSF. Furthermore, we also revisited the histology of the pituitary cleft and looked whether CSF drained in it. To answer such questions, we used scanning and transmission electron microscopy, intracerebroventricular infusion of Evan´s blue, fluorescent beads, and sodium fluorescein. The latter was measured in the pars distalis (PD) and various intracranial tissues. We found a pituitary capsule resembling leptomeninges, thick at the dorsal side of the pars intermedia (PI) and PD, thicker at the level of PI in contiguity with the PN and thinner at the rostro-ventral side as a thin membrane of fibroblast-like cells embedded in a fibrous layer. The capsule has abundant capillaries on all sides. Our results showed that the CSFs bathe between the capsule and the surface of the whole gland, and ciliate cells are present in the pituitary border. Our data suggest that the pituitary gland intercommunicates with the central nervous system (CNS) through the CSF.
Assuntos
Adeno-Hipófise , Hipófise , Humanos , Ratos , Animais , Hipófise/metabolismo , Hipotálamo , Adeno-Hipófise/metabolismoRESUMO
Whether neuroinflammation leads to dopaminergic nigrostriatal system neurodegeneration is controversial. We addressed this issue by inducing acute neuroinflammation in the substantia nigra (SN) with a single local administration (5 µg/2 µL saline solution) of lipopolysaccharide (LPS). Neuroinflammatory variables were assessed from 48 h to 30 days after the injury by immunostaining for activated microglia (Iba-1 +), neurotoxic A1 astrocytes (C3 + and GFAP +), and active caspase-1. We also evaluated NLRP3 activation and Il-1ß levels by western blot and mitochondrial complex I (CI) activity. Fever and sickness behavior was assessed for 24 h, and motor behavior deficits were followed up until day 30. On this day, we evaluated the cellular senescence marker ß-galactosidase (ß-Gal) in the SN and tyrosine hydroxylase (TH) in the SN and striatum. After LPS injection, Iba-1 (+), C3 (+), and S100A10 (+) cells were maximally present at 48 h and reached basal levels on day 30. NLRP3 activation occurred at 24 h and was followed by a rise of active caspase-1 (+), Il-1ß, and decreased mitochondrial CI activity until 48 h. A significant loss of nigral TH (+) cells and striatal terminals was associated with motor deficits on day 30. The remaining TH (+) cells were ß-Gal (+), suggesting senescent dopaminergic neurons. All the histopathological changes also appeared on the contralateral side. Our results show that unilaterally LPS-induced neuroinflammation can cause bilateral neurodegeneration of the nigrostriatal dopaminergic system and are relevant for understanding Parkinson's disease (PD) neuropathology.
Assuntos
Inflamassomos , Transtornos Parkinsonianos , Ratos , Animais , Inflamassomos/metabolismo , Lipopolissacarídeos/farmacologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Doenças Neuroinflamatórias , Transtornos Parkinsonianos/metabolismo , Substância Negra/metabolismo , Neurônios Dopaminérgicos/metabolismo , Caspase 1/metabolismo , Dopamina/metabolismo , Microglia/metabolismoRESUMO
Overexpression of neurotrophic factors in nigral dopamine neurons is a promising approach to reverse neurodegeneration of the nigrostriatal dopamine system, a hallmark in Parkinson's disease. The human cerebral dopamine neurotrophic factor (hCDNF) has recently emerged as a strong candidate for Parkinson's disease therapy. This study shows that hCDNF expression in dopamine neurons using the neurotensin-polyplex nanoparticle system reverses 6-hydroxydopamine-induced morphological, biochemical, and behavioral alterations. Three independent electron microscopy techniques showed that the neurotensin-polyplex nanoparticles containing the hCDNF gene, ranging in size from 20 to 150 nm, enabled the expression of a secretable hCDNF in vitro. Their injection in the substantia nigra compacta on day 21 after the 6-hydroxydopamine lesion resulted in detectable hCDNF in dopamine neurons, whose levels remained constant throughout the study in the substantia nigra compacta and striatum. Compared with the lesioned group, tyrosine hydroxylase-positive (TH+) nigral cell population and TH+ fiber density rose in the substantia nigra compacta and striatum after hCDNF transfection. An increase in ßIII-tubulin and growth-associated protein 43 phospho-S41 (GAP43p) followed TH+ cell recovery, as well as dopamine and its catabolite levels. Partial reversal (80%) of drug-activated circling behavior and full recovery of spontaneous motor and non-motor behavior were achieved. Brain-derived neurotrophic factor recovery in dopamine neurons that also occurred suggests its participation in the neurotrophic effects. These findings support the potential of nanoparticle-mediated hCDNF gene delivery to develop a disease-modifying treatment against Parkinson's disease. The Institutional Animal Care and Use Committee of Centro de Investigación y de Estudios Avanzados approved our experimental procedures for animal use (authorization No. 162-15) on June 9, 2019.
RESUMO
An understanding of the biochemistry of the giant cell tumour of bone (GCTB) provides an opportunity for the development of prognostic markers and identification of therapeutic targets. Based on metabolomic analysis, we proposed glycerophospholipid metabolism as the altered pathway in GCTB., The objective of this study was to identify these altered metabolites. Using phosphorus-31 nuclear magnetic resonance spectroscopy (31P-NMR), sphingomyelin was determined to be the most dysregulated phospholipid in tissue samples from six patients with GCTB. Enzymes related to its biosynthesis and hydrolysis were examined using immunodetection techniques. High expression of sphingomyelin synthases 1 and 2, but low expression of neutral sphingomyelinase 2 (nSMase2) was found in GCTB tissues compared to non-neoplastic bone tissues. Sphingomyelin/ceramide biosynthesis is dysregulated in GCTB due to alterations in the expression of SMS1, SMS2, and nSMase2.
Assuntos
Neoplasias Ósseas , Tumor de Células Gigantes do Osso , Osso e Ossos , Humanos , Espectroscopia de Ressonância Magnética , EsfingomielinasRESUMO
The current pandemic caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a public health emergency. To date, March 1, 2021, coronavirus disease 2019 (COVID-19) has caused about 114 million accumulated cases and 2.53 million deaths worldwide. Previous pieces of evidence suggest that SARS-CoV-2 may affect the central nervous system (CNS) and cause neurological symptoms in COVID-19 patients. It is also known that angiotensin-converting enzyme-2 (ACE2), the primary receptor for SARS-CoV-2 infection, is expressed in different brain areas and cell types. Thus, it is hypothesized that infection by this virus could generate or exacerbate neuropathological alterations. However, the molecular mechanisms that link COVID-19 disease and nerve damage are unclear. In this review, we describe the routes of SARS-CoV-2 invasion into the central nervous system. We also analyze the neuropathologic mechanisms underlying this viral infection, and their potential relationship with the neurological manifestations described in patients with COVID-19, and the appearance or exacerbation of some neurodegenerative diseases.
RESUMO
Chronic consumption of ß-sitosterol-ß-D-glucoside (BSSG), a neurotoxin contained in cycad seeds, leads to Parkinson's disease in humans and rodents. Here, we explored whether a single intranigral administration of BSSG triggers neuroinflammation and neurotoxic A1 reactive astrocytes besides dopaminergic neurodegeneration. We injected 6 µg BSSG/1 µL DMSO or vehicle into the left substantia nigra and immunostained with antibodies against tyrosine hydroxylase (TH) together with markers of microglia (OX42), astrocytes (GFAP, S100ß, C3), and leukocytes (CD45). We also measured nitric oxide (NO), lipid peroxidation (LPX), and proinflammatory cytokines (TNF-α, IL-1ß, IL-6). The Evans blue assay was used to explore the blood-brain barrier (BBB) permeability. We found that BSSG activates NO production on days 15 and 30 and LPX on day 120. Throughout the study, high levels of TNF-α were present in BSSG-treated animals, whereas IL-1ß was induced until day 60 and IL-6 until day 30. Immunoreactivity of activated microglia (899.0 ± 80.20%) and reactive astrocytes (651.50 ± 11.28%) progressively increased until day 30 and then decreased to remain 251.2 ± 48.8% (microglia) and 91.02 ± 39.8 (astrocytes) higher over controls on day 120. C3(+) cells were also GFAP and S100ß immunoreactive, showing they were neurotoxic A1 reactive astrocytes. BBB remained permeable until day 15 when immune cell infiltration was maximum. TH immunoreactivity progressively declined, reaching 83.6 ± 1.8% reduction on day 120. Our data show that BSSG acute administration causes chronic neuroinflammation mediated by activated microglia, neurotoxic A1 reactive astrocytes, and infiltrated immune cells. The severe neuroinflammation might trigger Parkinson's disease in BSSG intoxication.
Assuntos
Astrócitos/efeitos dos fármacos , Astrócitos/imunologia , Inflamação/etiologia , Neurotoxinas/imunologia , Sitosteroides/administração & dosagem , Substância Negra/efeitos dos fármacos , Substância Negra/metabolismo , Animais , Astrócitos/metabolismo , Biomarcadores , Doença Crônica , Citocinas/metabolismo , Modelos Animais de Doenças , Humanos , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Inflamação/patologia , Mediadores da Inflamação/metabolismo , Leucócitos/imunologia , Leucócitos/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Masculino , Microglia/imunologia , Microglia/metabolismo , Neurotoxinas/efeitos adversos , Estresse Oxidativo/efeitos dos fármacos , Doença de Parkinson/etiologia , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , Ratos , Substância Negra/patologiaRESUMO
Lipopolysaccharide (LPS) is a potent immunogen when administered locally and/or systemically. The peripheral immunization with LPS could contribute to the progression of neurological diseases because a strong link between neuroinflammation and dopaminergic degeneration has been found. The switch between the survival and neuronal death in substantia nigra could be related to M1 (neurotoxic) and M2 (neuroprotective) microglia phenotypes. In this review, we present the current findings about microglia roles, biomarkers, and natural or synthetic immune modulators determined in the LPS-based murine model.
Assuntos
Modelos Animais de Doenças , Inflamação/imunologia , Lipopolissacarídeos/farmacologia , Microglia/imunologia , Animais , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/imunologia , Humanos , Inflamação/induzido quimicamente , Microglia/efeitos dos fármacosRESUMO
An animal model, suitable for resembling Parkinson's disease (PD) progress, should show both, motor and non-motor alterations. However, these features have been scarcely evaluated or developed in parkinsonian models induced by neurotoxins. This protocol provides modifications to original methods, allowing six different motor and non-motor behavior tests, which adequately and timely emulate the main parkinsonian sensorimotor alterations in the rat or mouse: (1) bilateral sensorimotor alterations, examined by the vibrissae test; (2) balance and motor coordination, evaluated by the uncoordinated gait test; (3) locomotor asymmetry, analyzed by the cylinder test; (4) bradykinesia, as a locomotor alteration evidenced by the open field test; (5) depressive-like behavior, judged by the forced swimming test; and (6) hyposmia, assessed by the olfactory asymmetry test. Some advantages of using these behavioral tests over others include:â¢No sophisticated materials or equipment are required for their application and evaluation.â¢They are used in rodent models for parkinsonian research, but they can also be helpful for studying other movement disorders.â¢These tests can accurately discriminate the affected side from the healthy one, after unilateral injury of one hemisphere, resulting in sensorimotor, olfactory or locomotor asymmetry.
RESUMO
Parkinson's disease (PD) is a progressive neuropathology characterized by motor and non-motor alterations. ß-sitosterol ß-d-glucoside (BSSG) is a neurotoxin whose prolonged oral administration in rats has been proposed as a new PD model. Herein, we demonstrate that a single, unilateral, and intranigral administration of BSSG also elicits bilateral sensorimotor alterations in the rat. Six behavioral tests evaluated the effect of different concentrations of BSSG (3, 6, 9, and 12 µg/µL DMSO) from 15 to 120 days after administration. The first behavioral alterations, which appeared on day 15, were unbalanced and uncoordinated gaits and a decrease in the sensorimotor cortex activity, as evidenced by the beam-walking and the vibrissae tests, respectively. After 30 days, the corridor test revealed hyposmia and a decreased locomotor activity in the open field. The last alteration was a depressive-like behavior, as shown by the forced swim test on days 60 and 120. According to the cylinder test, no locomotor asymmetry was observed over time with any BSSG concentrations tested. Also, a mesencephalic TH(+) cell loss (p < 0.05) was shown on day 30 when compared with the mock condition, and such a loss was even higher on day 120. At this time, the presence of pathological α-synuclein aggregates in the mesencephalon was documented. Our results show that the stereotaxic intranigral administration of BSSG reproduces some characteristics of oral administration, such as the progression of behavioral alterations, dopaminergic neurons loss, and the presence of Lewy body-like synuclein aggregations, in less time and resources.
Assuntos
Anosmia , Depressão , Neurônios Dopaminérgicos , Transtornos Neurológicos da Marcha , Locomoção , Mesencéfalo , Neurotoxinas/farmacologia , Doença de Parkinson Secundária/induzido quimicamente , Doença de Parkinson , Córtex Sensório-Motor , Sitosteroides/farmacologia , Animais , Anosmia/induzido quimicamente , Anosmia/patologia , Anosmia/fisiopatologia , Depressão/induzido quimicamente , Depressão/patologia , Depressão/fisiopatologia , Modelos Animais de Doenças , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/patologia , Transtornos Neurológicos da Marcha/induzido quimicamente , Transtornos Neurológicos da Marcha/etiologia , Transtornos Neurológicos da Marcha/patologia , Transtornos Neurológicos da Marcha/fisiopatologia , Locomoção/efeitos dos fármacos , Locomoção/fisiologia , Masculino , Mesencéfalo/efeitos dos fármacos , Mesencéfalo/patologia , Mesencéfalo/fisiopatologia , Neurotoxinas/administração & dosagem , Doença de Parkinson/complicações , Doença de Parkinson/patologia , Doença de Parkinson/fisiopatologia , Ratos , Ratos Wistar , Córtex Sensório-Motor/fisiopatologia , Sitosteroides/administração & dosagem , Substância Negra/efeitos dos fármacosRESUMO
Models of Parkinson's disease with neurotoxins have shown that microglial activation does not evoke a typical inflammatory response in the substantia nigra, questioning whether neuroinflammation leads to neurodegeneration. To address this issue, the archetypal inflammatory stimulus, lipopolysaccharide (LPS), was injected into the rat substantia nigra. LPS induced fever, sickness behavior, and microglial activation (OX42 immunoreactivity), followed by astrocyte activation and leukocyte infiltration (GFAP and CD45 immunoreactivities). During the acute phase of neuroinflammation, pro- and anti-inflammatory cytokines (TNF-α, IL-1ß, IL-6, IL-4, and IL-10) responded differentially at mRNA and protein level. Increased NO production and lipid peroxidation occurred at 168 h after LPS injection. At this time, evidence of neurodegeneration could be seen, entailing decreased tyrosine hydroxylase (TH) immunoreactivity, irregular body contour, and prolongation discontinuity of TH+ cells, as well as apparent phagocytosis of TH+ cells by OX42+ cells. Altogether, these results show that LPS evokes a typical inflammatory response in the substantia nigra that is followed by dopaminergic neurodegeneration.
Assuntos
Astrócitos/fisiologia , Neurônios Dopaminérgicos/fisiologia , Leucócitos Mononucleares/fisiologia , Lipopolissacarídeos/imunologia , Microglia/fisiologia , Doenças Neurodegenerativas/imunologia , Inflamação Neurogênica/imunologia , Doença de Parkinson/imunologia , Parte Compacta da Substância Negra/imunologia , Tirosina 3-Mono-Oxigenase/imunologia , Doença Aguda , Animais , Diferenciação Celular , Movimento Celular , Células Cultivadas , Citocinas/metabolismo , Modelos Animais de Doenças , Humanos , Peroxidação de Lipídeos , Masculino , Ratos , Ratos WistarRESUMO
The structural effect of neurturin (NRTN) on the nigrostriatal dopaminergic system in animals remains unknown, although NRTN has been shown to be effective in Parkinson's disease animal models. Herein, we aimed to demonstrate that NRTN overexpression in dopaminergic neurons stimulates both neurite outgrowths in the nigrostriatal pathway and striatal dendritic spines in aging rats with chronic 6-hydroxydopamine (6-OHDA) lesion. At week 12 after lesion, pTracer-mNRTN-His or pGreenLantern-1 plasmids were intranigrally transfected using the NTS-polyplex nanoparticles system. We showed that the transgenic expression in dopaminergic neurons remained until the end of the study (12 weeks). Only animals expressing NRTN-His showed recovery of tyrosine hydroxylase (TH)+ cells (28 ± 2%), their neurites (32 ± 2%) and the neuron-specific cytoskeletal marker ß-III-tubulin in the substantia nigra; striatal TH(+) fibers were also recovered (52 ± 3%), when compared to the healthy condition. Neurotensin receptor type 1 levels were also significantly recovered in the substantia nigra and striatum. Dopamine recovery was 70 ± 4% in the striatum and complete in the substantia nigra. The number of dendritic spines of striatal medium spiny neurons was also significantly increased, but the recovery was not complete. Drug-activated circling behavior decreased by 73 ± 2% (methamphetamine) and 89 ± 1% (apomorphine). Similar decrease was observed in the spontaneous motor behavior. Our results demonstrate that NRTN causes presynaptic and postsynaptic restoration of the nigrostriatal dopaminergic system after a 6-OHDA-induced chronic lesion. However, those improvements did not reach the healthy condition, suggesting that NRTN exerts lesser neurotrophic effects than other neurotrophic approaches.
Assuntos
Neurônios Dopaminérgicos/metabolismo , Neurturina/metabolismo , Terminações Pré-Sinápticas/metabolismo , Animais , Corpo Estriado/metabolismo , Corpo Estriado/patologia , Citoesqueleto/metabolismo , Espinhas Dendríticas/metabolismo , Dopamina/metabolismo , Ensaio de Imunoadsorção Enzimática , Membro Anterior/fisiologia , Masculino , Camundongos , Neuritos/metabolismo , Oxidopamina , Ratos Wistar , Receptores de Neurotensina/metabolismo , Substância Negra/metabolismo , Substância Negra/patologia , Transfecção , Vibrissas/fisiologiaRESUMO
BACKGROUND: The neurotrophin Brain-Derived Neurotrophic Factor (BDNF) influences nigral dopaminergic neurons via autocrine and paracrine mechanisms. The reduction of BDNF expression in Parkinson's disease substantia nigra (SN) might contribute to the death of dopaminergic neurons because inhibiting BDNF expression in the SN causes parkinsonism in the rat. This study aimed to demonstrate that increasing BDNF expression in dopaminergic neurons of rats with one week of 6-hydroxydopamine lesion recovers from parkinsonism. The plasmids phDAT-BDNF-flag and phDAT-EGFP, coding for enhanced green fluorescent protein, were transfected using neurotensin (NTS)-polyplex, which enables delivery of genes into the dopaminergic neurons via neurotensin-receptor type 1 (NTSR1) internalization. RESULTS: Two weeks after transfections, RT-PCR and immunofluorescence techniques showed that the residual dopaminergic neurons retain NTSR1 expression and susceptibility to be transfected by the NTS-polyplex. phDAT-BDNF-flag transfection did not increase dopaminergic neurons, but caused 7-fold increase in dopamine fibers within the SN and 5-fold increase in innervation and dopamine levels in the striatum. These neurotrophic effects were accompanied by a significant improvement in motor behavior. CONCLUSIONS: NTS-polyplex-mediated BDNF overexpression in dopaminergic neurons has proven to be effective to remit hemiparkinsonism in the rat. This BDNF gene therapy might be helpful in the early stage of Parkinson's disease.
Assuntos
Fator Neurotrófico Derivado do Encéfalo/biossíntese , Neurônios Dopaminérgicos , Neurotensina , Doença de Parkinson , Substância Negra , Transfecção/métodos , Animais , Fator Neurotrófico Derivado do Encéfalo/genética , Modelos Animais de Doenças , Neurônios Dopaminérgicos/metabolismo , Neurônios Dopaminérgicos/patologia , Terapia Genética/métodos , Masculino , Neurotensina/química , Neurotensina/farmacologia , Doença de Parkinson/genética , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , Doença de Parkinson/terapia , Ratos , Ratos Wistar , Receptores de Neurotensina/metabolismo , Substância Negra/metabolismo , Substância Negra/patologiaRESUMO
Neurotensin (NTS)-polyplex is a gene nanocarrier that has potential nanomedicine-based applications for the treatment of Parkinson's disease and cancers of cells expressing NTS receptor type 1. We assessed the acute inflammatory response to NTS-polyplex carrying a reporter gene in BALB/c mice. The intravenous injection of NTS-polyplex caused the specific expression of the reporter gene in gastrointestinal cells. Six hours after an intravenous injection of propidium iodide labeled-NTS-polyplex, fluorescent spots were located in the cells of the organs with a mononuclear phagocyte system, suggesting NTS-polyplex clearance. In contrast to lipopolysaccharide and carbon tetrachloride, NTS-polyplex did not increase the serum levels of tumor necrosis factor alpha, interleukin (IL)-1ß, IL-6, bilirubin, aspartate transaminase, and alanine transaminase. NTS-polyplex increased the levels of serum amyloid A and alkaline phosphatase, but these levels normalized after 24 h. Compared to carrageenan, the local injection of NTS-polyplex did not produce inflammation. Our results support the safety of NTS-polyplex. FROM THE CLINICAL EDITOR: This study focuses on the safety of neurotensin (NTS)-polyplex, a gene nanocarrier that has potential in the treatment of Parkinson's disease and cancers of cells expressing NTS receptor type 1. NTS polyplex demonstrates a better safety profile compared with carrageenan, lipopolysaccharide, and carbon tetrachloride in a murine model.