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1.
Nat Commun ; 10(1): 1498, 2019 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-30940800

RESUMO

WNTs are lipid-modified proteins that control multiple functions in development and disease via short- and long-range signaling. However, it is unclear how these hydrophobic molecules spread over long distances in the mammalian brain. Here we show that WNT5A is produced by the choroid plexus (ChP) of the developing hindbrain, but not the telencephalon, in both mouse and human. Since the ChP produces and secretes the cerebrospinal fluid (CSF), we examine the presence of WNT5A in the CSF and find that it is associated with lipoprotein particles rather than exosomes. Moreover, since the CSF flows along the apical surface of hindbrain progenitors not expressing Wnt5a, we examined whether deletion of Wnt5a in the ChP controls their function and find that cerebellar morphogenesis is impaired. Our study thus identifies the CSF as a route and lipoprotein particles as a vehicle for long-range transport of biologically active WNT in the central nervous system.


Assuntos
Lipoproteínas/líquido cefalorraquidiano , Rombencéfalo/embriologia , Proteína Wnt-5a/metabolismo , Animais , Transporte Biológico , Plexo Corióideo/metabolismo , Feminino , Humanos , Masculino , Camundongos Endogâmicos ICR , Morfogênese , Rombencéfalo/metabolismo , Transdução de Sinais , Proteína Wnt-5a/genética
2.
Neurobiol Dis ; 121: 95-105, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30261283

RESUMO

The involvement of the 18kDa translocator protein (TSPO), a marker of neuroinflammation, in Alzheimer's disease (AD) remains controversial. In the present report, we used [125I]-CLINDE, a SPECT TSPO radiotracer never before used in AD, and we investigated the relationship between TSPO and amyloid plaque density (using [125I]-DRM106) in a triple transgenic mouse model of AD (3xTgAD, APPSWE, PS1M146V and TauP301L). Our results show that TSPO increases appear before those of amyloid deposits. Moreover, the different parts of the hippocampus are differentially affected. Indeed, for both TSPO and amyloid, the subiculum is affected earlier and the ventral hippocampus later than the dorsal hippocampus. In the subiculum and the dorsal hippocampus of 3xTgAD mice, a positive correlation between TSPO and of amyloid deposit levels is observed. This data supports the hypothesis that TSPO could be used as a predictive marker of amyloid pathology. In addition, our immunohistochemical data shows a segregation of TSPO in the hippocampus and immunofluorescence imaging revealed a mainly microglial origin of the TSPO expression. Thus, imaging TSPO with CLINDE may be a good alternative to PET radiotracers.


Assuntos
Doença de Alzheimer/metabolismo , Hipocampo/metabolismo , Placa Amiloide/metabolismo , Receptores de GABA/metabolismo , Doença de Alzheimer/complicações , Doença de Alzheimer/diagnóstico por imagem , Animais , Plexo Corióideo/metabolismo , Modelos Animais de Doenças , Encefalite/complicações , Encefalite/metabolismo , Feminino , Hipocampo/diagnóstico por imagem , Humanos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Tomografia Computadorizada de Emissão de Fóton Único/métodos
3.
Fluids Barriers CNS ; 15(1): 34, 2018 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-30541599

RESUMO

BACKGROUND: The roles of the choroid plexus (CP) and cerebrospinal fluid (CSF) production have drawn increasing attention in Alzheimer's disease (AD) research. Specifically, studies document markedly decreased CSF production and turnover in moderate-to-severe AD. Moreover, reduced CP function and CSF turnover lead to impaired clearance of toxic metabolites, likely promote neuroinflammation, and may facilitate neuronal death during AD progression. We analyzed CP gene expression in AD compared with control subjects, specifically considering those genes involved with CSF production and CP structural integrity. METHODS: The Brown-Merck Gene Expression Omnibus (GEO) database (CP transcripts) was mined to examine changes in gene expression in AD compared to controls with a focus on assorted genes thought to play a role in CSF production. Specifically, genes coding for ion transporters in CP epithelium (CPE) and associated enzymes like Na-K-ATPase and carbonic anhydrase, aquaporins, mitochondrial transporters/enzymes, blood-cerebrospinal fluid barrier (BCSFB) stability proteins, and pro-inflammatory mediators were selected for investigation. Data were analyzed using t test p-value and fold-change analysis conducted by the GEO2R feature of the GEO database. RESULTS: Significant expression changes for several genes were observed in AD CP. These included disruptions to ion transporters (e.g., the solute carrier gene SLC4A5, p = 0.004) and associated enzyme expressions (e.g., carbonic anhydrase CA4, p = 0.0001), along with decreased expression of genes involved in BCSFB integrity (e.g., claudin CLDN5, p = 0.039) and mitochondrial ATP synthesis (e.g., adenosine triphosphate ATP5L, p = 0.0004). Together all changes point to disrupted solute transport at the blood-CSF interface in AD. Increased expression of pro-inflammatory (e.g., interleukin IL1RL1, p = 0.00001) and potential neurodegenerative genes (e.g., amyloid precursor APBA3, p = 0.002) also implicate disturbed CP function. CONCLUSIONS: Because the altered expression of numerous transcripts in AD-CP help explain decreased CSF production in AD, these findings represent a first step towards identifying novel therapeutic targets in AD.


Assuntos
Doença de Alzheimer/líquido cefalorraquidiano , Doença de Alzheimer/genética , Encéfalo/metabolismo , Plexo Corióideo/metabolismo , Doença de Alzheimer/metabolismo , Barreira Hematoencefálica/metabolismo , Bases de Dados Factuais , Expressão Gênica , Perfilação da Expressão Gênica , Homeostase , Humanos , Transporte de Íons
4.
Mediators Inflamm ; 2018: 9150207, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30402044

RESUMO

The study was designed to examine whether the administration of neostigmine (0.5 mg/animal), a peripheral inhibitor of acetylcholinesterase (AChE), during an immune/inflammatory challenge provoked by intravenous injection of bacterial endotoxin-lipopolysaccharide (LPS; 400 ng/kg)-attenuates the synthesis of proinflammatory cytokines in the ovine preoptic area (POA), the hypothalamic structure playing an essential role in the control of the reproduction process, and in the choroid plexus (CP), a multifunctional organ sited at the interface between the blood and cerebrospinal fluid in the ewe. Neostigmine suppressed (p < 0.05) LPS-stimulated synthesis of cytokines such as interleukin- (IL-) 1ß, IL-6, and tumor necrosis factor (TNF) α in the POA, and this effect was similar to that induced by the treatment with systemic AChE inhibitor-donepezil (2.5 mg/animal). On the other hand, both AChE inhibitors did not influence the gene expression of these cytokines and their corresponding receptors in the CP. It was found that this structure seems to not express the neuronal acetylcholine (ACh) receptor subunit alpha-7, required for anti-inflammatory action of ACh. The mechanism of action involves inhibition of the proinflammatory cytokine synthesis on the periphery as well as inhibition of their de novo synthesis rather in brain microvessels and not in the CP. In conclusion, it is suggested that the AChE inhibitors incapable of reaching brain parenchyma might be used in the treatment of neuroinflammatory processes induced by peripheral inflammation.


Assuntos
Plexo Corióideo/metabolismo , Citocinas/metabolismo , Inflamação/induzido quimicamente , Inflamação/metabolismo , Lipopolissacarídeos/toxicidade , Neostigmina/uso terapêutico , Área Pré-Óptica/metabolismo , Animais , Inibidores da Colinesterase/uso terapêutico , Plexo Corióideo/efeitos dos fármacos , Ensaio de Imunoadsorção Enzimática , Feminino , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Interleucina-1beta/sangue , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Área Pré-Óptica/efeitos dos fármacos , Ovinos , Fator de Necrose Tumoral alfa/metabolismo
5.
J Pineal Res ; 65(4): e12528, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30260503

RESUMO

The cerebrospinal fluid melatonin is released from the pineal gland, directly into the third ventricle, or produced de novo in the brain from extrapineal melatonin sources leading to a melatonin concentration gradient in the cerebrospinal fluid. Despite the interest on this topic, the brain areas capable of producing melatonin are not yet clear. Bearing this in mind, we hypothesized that the choroid plexus (CP) could be one of these melatonin sources. We analyzed and confirmed the presence of the four enzymes required for melatonin synthesis in rat CP and demonstrated that arylalkylamine N-acetyltransferase shows a circadian expression in female and male rat CP. Specifically, this enzyme colocalizes with mitochondria in rat CP epithelial cells, an organelle known to be involved in melatonin function and synthesis. Then, we demonstrated that melatonin is synthesized by porcine CP explants, although without a circadian pattern. In conclusion, our data show that the CP is a local source of melatonin to the central nervous system, probably contributing to its high levels in the cerebrospinal fluid. We believe that in the CP, melatonin might be regulated by its endogenous clock machinery and by the hormonal background.


Assuntos
Encéfalo/metabolismo , Sistema Nervoso Central/metabolismo , Plexo Corióideo/metabolismo , Melatonina/metabolismo , Animais , Líquido Cefalorraquidiano/metabolismo , Feminino , Masculino , Ratos
6.
CNS Neurol Disord Drug Targets ; 17(10): 743-756, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30179148

RESUMO

BACKGROUND & OBJECTIVE: Regulation of composition, volume and turnover of fluids surrounding the brain and damp cells is vital. These fluids transport all substances required for cells and remove the unwanted materials. This regulation tends to act as barrier to prevent free exchange of materials between the brain and blood. There are specific mechanisms concerned with fluid secretion of the controlled composition of the brain, and others responsible for reabsorption eventually to blood and the extracellular fluid whatever their composition is. The current view assumes that choroidal plexuses secrete the major part of Cerebrospinal Fluid (CSF), while the Blood-Brain Barrier (BBB) has a much less contribution to fluid production, generating Interstitial Fluid (ISF) that drains to CSF. The skull is a rigid box; thereby the sum of volumes occupied by the parenchyma with its ISF, related connective tissue, the vasculature, the meninges and the CSF must be relatively constant according to the Monroe-Kellie dogma. This constitutes a formidable challenge that normal organisms surpass daily. The ISF and CSF provide water and solutes influx and efflux from cells to these targeted fluids in a quite precise way. Microvessels within the parenchyma are sufficiently close to every cell where diffusion areas for solutes are tiny. Despite this, CSF and ISF exhibit very similar compositions, but differ significantly from blood plasma. Many hydrophilic substances are effectively prevented from the entry into the brain via blood, while others like neurotransmitters are extremely hindered from getting out of the brain. Anatomical principle of the barrier and routes of fluid transfer cannot explain the extraordinary accuracy of fluids and substances needed to enter or leave the brain firmly. There is one aspect that has not been deeply analyzed, despite being prevalent in all the above processes, it is considered a part of the CSF and ISF dynamics. This aspect is the energy necessary to propel them properly in time, form, space, quantity and temporality. CONCLUSION: The recent hypothesis based on glucose and ATP as sources of energy presents numerous contradictions and controversies. The discovery of the unsuspected intrinsic ability of melanin to dissociate and reform water molecules, similar to the role of chlorophyll in plants, was confirmed in the study of ISF and CSF biology.


Assuntos
Transporte Biológico/fisiologia , Barreira Hematoencefálica/fisiologia , Encéfalo/fisiologia , Líquido Cefalorraquidiano/metabolismo , Melaninas/metabolismo , Equilíbrio Hidroeletrolítico/fisiologia , Animais , Edema Encefálico/líquido cefalorraquidiano , Edema Encefálico/metabolismo , Plexo Corióideo/metabolismo , Plexo Corióideo/ultraestrutura , Homeostase , Humanos , Melaninas/química
7.
J Neuroinflammation ; 15(1): 254, 2018 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-30180861

RESUMO

BACKGROUND: The complement system plays an important role in many neurological disorders. Complement modulation, including C3/C3a receptor signaling, shows promising therapeutic effects on cognition and neurodegeneration. Yet, the implications for this pathway in perioperative neurocognitive disorders (PND) are not well established. Here, we evaluated the possible role for C3/C3a receptor signaling after orthopedic surgery using an established mouse model of PND. METHODS: A stabilized tibial fracture surgery was performed in adult male C57BL/6 mice under general anesthesia and analgesia to induce PND-like behavior. Complement activation was assessed in the hippocampus and choroid plexus. Changes in hippocampal neuroinflammation, synapse numbers, choroidal blood-cerebrospinal fluid barrier (BCSFB) integrity, and hippocampal-dependent memory function were evaluated after surgery and treatment with a C3a receptor blocker. RESULTS: C3 levels and C3a receptor expression were specifically increased in hippocampal astrocytes and microglia after surgery. Surgery-induced neuroinflammation and synapse loss in the hippocampus were attenuated by C3a receptor blockade. Choroidal BCSFB dysfunction occurred 1 day after surgery and was attenuated by C3a receptor blockade. Administration of exogenous C3a exacerbated cognitive decline after surgery, whereas C3a receptor blockade improved hippocampal-dependent memory function. CONCLUSIONS: Orthopedic surgery activates complement signaling. C3a receptor blockade may be therapeutically beneficial to attenuate neuroinflammation and PND.


Assuntos
Ativação do Complemento/fisiologia , Proteínas do Sistema Complemento/metabolismo , Hipocampo/metabolismo , Transtornos Neurocognitivos , Complicações Pós-Operatórias/fisiopatologia , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Barreira Hematoencefálica/fisiopatologia , Plexo Corióideo/metabolismo , Ativação do Complemento/efeitos dos fármacos , Fator I do Complemento/farmacologia , Condicionamento Clássico/efeitos dos fármacos , Condicionamento Clássico/fisiologia , Citofagocitose/efeitos dos fármacos , Modelos Animais de Doenças , Medo/psicologia , Hipocampo/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microglia/efeitos dos fármacos , Microglia/metabolismo , Transtornos Neurocognitivos/tratamento farmacológico , Transtornos Neurocognitivos/etiologia , Transtornos Neurocognitivos/metabolismo , Transtornos Neurocognitivos/patologia , Complicações Pós-Operatórias/tratamento farmacológico , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Sinapses/efeitos dos fármacos , Sinapses/patologia , Fraturas da Tíbia/cirurgia , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/fisiologia
8.
Fluids Barriers CNS ; 15(1): 22, 2018 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-30111340

RESUMO

BACKGROUND: Choroid plexus epithelial cells express high levels of transthyretin, produce cerebrospinal fluid and many of its proteins, and make up the blood-cerebrospinal fluid barrier. Choroid plexus epithelial cells are vital to brain health and may be involved in neurological diseases. Transgenic mice containing fluorescent and luminescent reporters of these cells would facilitate their study in health and disease, but prior transgenic reporters lost expression over the early postnatal period. METHODS: Human bacterial artificial chromosomes in which the transthyretin coding sequence was replaced with DNA for tdTomato or luciferase 2 were used in pronuclear injections to produce transgenic mice. These mice were characterized by visualizing red fluorescence, immunostaining, real-time reverse transcription polymerase chain reaction, and luciferase enzyme assay. RESULTS: Reporters were faithfully expressed in cells that express transthyretin constitutively, including choroid plexus epithelial cells, retinal pigment epithelium, pancreatic islets, and liver. Expression of tdTomato in choroid plexus began at the appropriate embryonic age, being detectable by E11.5. Relative levels of tdTomato transcript in the liver and choroid plexus paralleled relative levels of transcripts for transthyretin. Expression remained robust over the first postnatal year, although choroid plexus transcripts of tdTomato declined slightly with age whereas transthyretin remained constant. TdTomato expression patterns were consistent across three founder lines, displayed no sex differences, and were stable across several generations. Two of the tdTomato lines were bred to homozygosity, and homozygous mice are healthy and fertile. The usefulness of tdTomato reporters in visualizing and analyzing live Transwell cultures was demonstrated. Luciferase activity was very high in homogenates of choroid plexus and continued to be expressed through adulthood. Luciferase also was detectable in eye and pancreas. CONCLUSIONS: Transgenic mice bearing fluorescent and luminescent reporters of transthyretin should prove useful for tracking transplanted choroid plexus epithelial cells, for purifying the cells, and for reporting their derivation from stem cells. They also should prove useful for studying transthyretin synthesis by other cell types, as transthyretin has been implicated in many functions and conditions, including clearance of ß-amyloid peptides associated with Alzheimer's disease, heat shock in neurons, processing of neuropeptides, nerve regeneration, astrocyte metabolism, and transthyretin amyloidosis.


Assuntos
Plexo Corióideo/citologia , Células Epiteliais/citologia , Proteínas Luminescentes/metabolismo , Camundongos Transgênicos , Modelos Animais , Pré-Albumina/metabolismo , Animais , Técnicas de Cultura de Células , Células Cultivadas , Plexo Corióideo/crescimento & desenvolvimento , Plexo Corióideo/metabolismo , Cromossomos Artificiais Bacterianos , Células Epiteliais/metabolismo , Humanos , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/crescimento & desenvolvimento , Ilhotas Pancreáticas/metabolismo , Fígado/citologia , Fígado/crescimento & desenvolvimento , Fígado/metabolismo , Proteínas Luminescentes/genética , Pré-Albumina/genética , RNA Mensageiro/metabolismo , Epitélio Pigmentado da Retina/citologia , Epitélio Pigmentado da Retina/crescimento & desenvolvimento , Epitélio Pigmentado da Retina/metabolismo
9.
J Neuroinflammation ; 15(1): 236, 2018 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-30134924

RESUMO

BACKGROUND: Very late antigen 4 (VLA-4; integrin α4ß1) is critical for transmigration of T helper (TH) 1 cells into the central nervous system (CNS) under inflammatory conditions such as multiple sclerosis (MS). We have previously shown that VLA-4 and melanoma cell adhesion molecule (MCAM) are important for trans-endothelial migration of human TH17 cells in vitro and here investigate their contribution to pathogenic CNS inflammation. METHODS: Antibody blockade of VLA-4 and MCAM is assessed in murine models of CNS inflammation in conjunction with conditional ablation of α4-integrin expression in T cells. Effects of VLA-4 and MCAM blockade on lymphocyte migration are further investigated in the human system via in vitro T cell transmigration assays. RESULTS: Compared to the broad effects of VLA-4 blockade on encephalitogenic T cell migration over endothelial barriers, MCAM blockade impeded encephalitogenic T cell migration in murine models of MS that especially depend on CNS migration across the choroid plexus (CP). In transgenic mice lacking T cell α4-integrin expression (CD4::Itga4-/-), MCAM blockade delayed disease onset. Migration of MCAM-expressing T cells through the CP into the CNS was restricted, where laminin 411 (composed of α4, ß1, γ1 chains), the proposed major ligand of MCAM, is detected in the endothelial basement membranes of murine CP tissue. This finding was translated to the human system; blockade of MCAM with a therapeutic antibody reduced in vitro transmigration of MCAM-expressing T cells across a human fibroblast-derived extracellular matrix layer and a brain-derived endothelial monolayer, both expressing laminin α4. Laminin α4 was further detected in situ in CP endothelial-basement membranes in MS patients' brain tissue. CONCLUSIONS: Our findings suggest that MCAM-laminin 411 interactions facilitate trans-endothelial migration of MCAM-expressing T cells into the CNS, which seems to be highly relevant to migration via the CP and to potential future clinical applications in neuroinflammatory disorders.


Assuntos
Antígeno CD146/metabolismo , Plexo Corióideo/patologia , Encefalomielite Autoimune Experimental/patologia , Linfócitos T/efeitos dos fármacos , Animais , Anticorpos/uso terapêutico , Antígeno CD146/imunologia , Movimento Celular/efeitos dos fármacos , Movimento Celular/fisiologia , Células Cultivadas , Sistema Nervoso Central/patologia , Plexo Corióideo/diagnóstico por imagem , Plexo Corióideo/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Encefalomielite Autoimune Experimental/induzido quimicamente , Células Endoteliais/efeitos dos fármacos , Adjuvante de Freund/toxicidade , Humanos , Integrina alfa4beta1/genética , Integrina alfa4beta1/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Glicoproteína Mielina-Oligodendrócito/toxicidade , Fragmentos de Peptídeos/toxicidade , Proteínas Quinases/genética , Proteínas Quinases/metabolismo
10.
J Chem Neuroanat ; 94: 1-7, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30118754

RESUMO

The eusocial Damaraland mole-rat (Fukomys damarensis) represents an extreme example of reproductive skew, in that reproduction is completely blocked in female subordinate group members. It is thought that in these animals normal GnRH secretion from the hypothalamus is disrupted. Prolactin, a peptide hormone secreted from the anterior pituitary gland, has been implicated in a wide variety of functions. Well documented in rodents is its role in mediating lactational infertility. Elevated circulating prolactin levels, such as during lactation, are associated with reduced GnRH release into the portal blood and with a reduction in the frequency and amplitude of LH pulses. The present study aimed at investigating whether such a mechanism could act in reproductively suppressed female Damaraland mole-rats. By means of in situ hybridisation we studied the distribution and gene expression of the prolactin receptor (Prlr) in wild-caught female Damaraland mole-rats with different reproductive status. Substantial Prlr expression was found in several brain regions, with highest levels in the choroid plexus and moderate expression in the preoptic and tuberal hypothalamus. While in reproductive and non-reproductive females plasma prolactin levels were very low and not significantly different, quantification of the Prlr hybridisation signal revealed significant differences in relation to reproductive status. Reproductively suppressed females had increased expression of Prlr in the choroid plexus and in the arcuate nucleus (ARC) when compared to reproductive females. This suggests higher local prolactin levels in the brain of suppressed females. Together with previous findings, it could indicate that prolactin inhibits ARC kisspeptin neurons, which then would lead to reduced activation of GnRH neurons in such females.


Assuntos
Plexo Corióideo/metabolismo , Hipotálamo/metabolismo , Prolactina/sangue , Receptores da Prolactina/metabolismo , Reprodução/fisiologia , Animais , Feminino , Hormônio Liberador de Gonadotropina/metabolismo , Ratos-Toupeira , Neurônios/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores da Prolactina/genética
11.
J Trace Elem Med Biol ; 49: 128-133, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29895361

RESUMO

The role of the choroid plexus (CP) in iron (Fe) homeostasis has been suggested as the main mechanism of Fe uptake and storage in the mammalian central nervous system. Thus, the CP of the lateral and fourth ventricles was studied in guinea pigs with light and electron microscopy using methods including Perls' Prussian blue and Gomori acid phosphatase staining, immunoreactivity for ferritin and transferrin, as well as energy dispersive spectrometry microanalysis. The present study reveals the presence of endogenous Fe in CP epithelial cells. Under light microscopy, Prussian blue staining revealed dark blue precipitates (i.e., Fe3+) with a preferentially perinuclear localization. The Fe was also positive for such granules with similar cellular localization. Ultrastructural analysis demonstrated the presence of dense bodies and siderosomes with molecular ferritin. The spectra obtained by the microanalysis demonstrated emissions for Fe, both in dense bodies and siderosomes. This study suggests that guinea pig CP epithelial cells accumulate Fe in the form of ferritin, possibly in cytoplasmic organelles such as lysosomes.


Assuntos
Plexo Corióideo/metabolismo , Ferro/metabolismo , Microscopia Eletrônica de Transmissão/métodos , Animais , Ferritinas/metabolismo , Cobaias , Lisossomos/metabolismo , Masculino
12.
J Physiol ; 596(19): 4709-4728, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29956324

RESUMO

KEY POINTS: Normal pH is crucial for proper functioning of the brain, and disorders increasing the level of CO2 in the blood lead to a decrease in brain pH. CO2 can easily cross the barriers of the brain and will activate chemoreceptors leading to an increased exhalation of CO2 . The low pH, however, is harmful and bases such as HCO3 - are imported across the brain barriers in order to normalize brain pH. We show that the HCO3 - transporter NBCe2 in the choroid plexus of the blood-cerebrospinal fluid barrier is absolutely necessary for normalizing CSF pH during high levels of CO2 . This discovery represents a significant step in understanding the molecular mechanisms behind regulation of CSF pH during acid-base disturbances, such as chronic lung disease. ABSTRACT: The choroid plexus epithelium (CPE) is located in the brain ventricles where it produces the majority of the cerebrospinal fluid (CSF). The hypothesis that normal brain function is sustained by CPE-mediated CSF pH regulation by extrusion of acid-base equivalents was tested by determining the contribution of the electrogenic Na+ -HCO3 - cotransporter NBCe2 to CSF pH regulation. A novel strain of NBCe2 (Slc4a5) knockout (KO) mice was generated and validated. The base extrusion rate after intracellular alkalization was reduced by 77% in NBCe2 KO mouse CPE cells compared to control mice. NBCe2 KO mice and mice with CPE-targeted NBCe2 siRNA knockdown displayed a reduction in CSF pH recovery during hypercapnia-induced acidosis of approximately 85% and 90%, respectively, compared to control mice. NBCe2 KO did not affect baseline respiration rate or tidal volume, and the NBCe2 KO and wild-type (WT) mice displayed similar ventilatory responses to 5% CO2 exposure. NBCe2 KO mice were not protected against pharmacological or heating-induced seizure development. In conclusion, we establish the concept that the CPE is involved in the regulation of CSF pH by demonstrating that NBCe2 is necessary for proper CSF pH recovery after hypercapnia-induced acidosis.


Assuntos
Bicarbonatos/metabolismo , Líquido Cefalorraquidiano/metabolismo , Plexo Corióideo/metabolismo , Simportadores de Sódio-Bicarbonato/fisiologia , Sódio/metabolismo , Acidose Respiratória/etiologia , Acidose Respiratória/patologia , Acidose Respiratória/prevenção & controle , Doença Aguda , Animais , Líquido Cefalorraquidiano/química , Concentração de Íons de Hidrogênio , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Convulsões/etiologia , Convulsões/patologia
13.
Fluids Barriers CNS ; 15(1): 18, 2018 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-29848382

RESUMO

BACKGROUND: In Alzheimer's disease, there are striking changes in CSF composition that relate to altered choroid plexus (CP) function. Studying CP tissue gene expression at the blood-cerebrospinal fluid barrier could provide further insight into the epithelial and stromal responses to neurodegenerative disease states. METHODS: Transcriptome-wide Affymetrix microarrays were used to determine disease-related changes in gene expression in human CP. RNA from post-mortem samples of the entire lateral ventricular choroid plexus was extracted from 6 healthy controls (Ctrl), 7 patients with advanced (Braak and Braak stage III-VI) Alzheimer's disease (AD), 4 with frontotemporal dementia (FTD) and 3 with Huntington's disease (HuD). Statistics and agglomerative clustering were accomplished with MathWorks, MatLab; and gene set annotations by comparing input sets to GeneGo ( http://www.genego.com ) and Ingenuity ( http://www.ingenuity.com ) pathway sets. Bonferroni-corrected hypergeometric p-values of < 0.1 were considered a significant overlap between sets. RESULTS: Pronounced differences in gene expression occurred in CP of advanced AD patients vs. Ctrls. Metabolic and immune-related pathways including acute phase response, cytokine, cell adhesion, interferons, and JAK-STAT as well as mTOR were significantly enriched among the genes upregulated. Methionine degradation, claudin-5 and protein translation genes were downregulated. Many gene expression changes in AD patients were observed in FTD and HuD (e.g., claudin-5, tight junction downregulation), but there were significant differences between the disease groups. In AD and HuD (but not FTD), several neuroimmune-modulating interferons were significantly enriched (e.g., in AD: IFI-TM1, IFN-AR1, IFN-AR2, and IFN-GR2). AD-associated expression changes, but not those in HuD and FTD, were enriched for upregulation of VEGF signaling and immune response proteins, e.g., interleukins. HuD and FTD patients distinctively displayed upregulated cadherin-mediated adhesion. CONCLUSIONS: Our transcript data for human CP tissue provides genomic and mechanistic insight for differential expression in AD vs. FTD vs. HuD for stromal as well as epithelial components. These choroidal transcriptome characterizations elucidate immune activation, tissue functional resiliency, and CSF metabolic homeostasis. The BCSFB undergoes harmful, but also important functional and adaptive changes in neurodegenerative diseases; accordingly, the enriched JAK-STAT and mTOR pathways, respectively, likely help the CP in adaptive transcription and epithelial repair and/or replacement when harmed by neurodegeneration pathophysiology. We anticipate that these precise CP translational data will facilitate pharmacologic/transgenic therapies to alleviate dementia.


Assuntos
Doença de Alzheimer/metabolismo , Plexo Corióideo/metabolismo , Demência Frontotemporal/metabolismo , Doença de Huntington/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Expressão Gênica , Homeostase/fisiologia , Humanos , Masculino , Análise em Microsséries , Pessoa de Meia-Idade , Transcriptoma
14.
Nat Commun ; 9(1): 2167, 2018 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-29867199

RESUMO

Cerebrospinal fluid (CSF) production occurs at a rate of 500 ml per day in the adult human. Conventional osmotic forces do not suffice to support such production rate and the molecular mechanisms underlying this fluid production remain elusive. Using ex vivo choroid plexus live imaging and isotope flux in combination with in vivo CSF production determination in mice, we identify a key component in the CSF production machinery. The Na+/K+/2Cl- cotransporter (NKCC1) expressed in the luminal membrane of choroid plexus contributes approximately half of the CSF production, via its unusual outward transport direction and its unique ability to directly couple water transport to ion translocation. We thereby establish the concept of cotransport of water as a missing link in the search for molecular pathways sustaining CSF production and redefine the current model of this pivotal physiological process. Our results provide a rational pharmacological target for pathologies involving disturbed brain fluid dynamics.


Assuntos
Líquido Cefalorraquidiano/metabolismo , Plexo Corióideo/metabolismo , Membro 2 da Família 12 de Carreador de Soluto/metabolismo , Água/metabolismo , Animais , Transporte Biológico Ativo , Membrana Celular/metabolismo , Feminino , Expressão Gênica , Humanos , Masculino , Camundongos Endogâmicos C57BL , Microscopia de Fluorescência , Oócitos/metabolismo , Membro 2 da Família 12 de Carreador de Soluto/genética , Xenopus laevis
15.
Am J Physiol Cell Physiol ; 315(4): C445-C456, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-29949405

RESUMO

Hydrogen peroxide, released at low physiological concentration, is involved in different cell signaling pathways during brain development. When released at supraphysiological concentrations in brain fluids following an inflammatory, hypoxic, or toxic stress, it can initiate lipid peroxidation, protein, and nucleic acid damage and contribute to long-term neurological impairment associated with perinatal diseases. We found high glutathione peroxidase and glutathione reductase enzymatic activities in both lateral and fourth ventricle choroid plexus tissue isolated from developing rats, in comparison to the cerebral cortex and liver. Consistent with these, a high protein expression of glutathione peroxidases 1 and 4 was observed in choroid plexus epithelial cells, which form the blood-cerebrospinal fluid barrier. Live choroid plexuses isolated from newborn rats were highly efficient in detoxifying H2O2 from mock cerebrospinal fluid, illustrating the capacity of the choroid plexuses to control H2O2 concentration in the ventricular system of the brain. We used a differentiated cellular model of the blood-cerebrospinal fluid barrier coupled to kinetic and inhibition analyses to show that glutathione peroxidases are more potent than catalase to detoxify extracellular H2O2 at concentrations up to 250 µM. The choroidal cells also formed an enzymatic barrier preventing blood-borne hydroperoxides to reach the cerebrospinal fluid. These data point out the choroid plexuses as key structures in the control of hydroperoxide levels in the cerebral fluid environment during development, at a time when the protective glial cell network is still immature. Glutathione peroxidases are the main effectors of this choroidal hydroperoxide inactivation.


Assuntos
Encéfalo/metabolismo , Líquido Cefalorraquidiano/metabolismo , Plexo Corióideo/metabolismo , Peróxido de Hidrogênio/metabolismo , Animais , Barreira Hematoencefálica/metabolismo , Células Epiteliais/metabolismo , Feminino , Masculino , Ratos , Ratos Sprague-Dawley
16.
Am J Physiol Cell Physiol ; 315(3): C357-C366, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-29791207

RESUMO

The choroid plexus (CP) epithelium plays a major role in the production of cerebrospinal fluid (CSF). A polarized cell line, the porcine CP-Riems (PCP-R) line, which exhibits many of the characteristics of the native epithelium, was used to study the effect of activation of the transient receptor potential vanilloid 4 (TRPV4) cation channel found in the PCP-R cells as well as in the native epithelium. Ussing-style electrophysiological experiments showed that activation of TRPV4 with a specific agonist, GSK1016790A, resulted in an immediate increase in both transepithelial ion flux and conductance. These changes were inhibited by either of two distinct antagonists, HC067047 or RN1734. The change in conductance was reversible and did not involve disruption of epithelial junctional complexes. Activation of TRPV4 results in Ca2+ influx, therefore, we examined whether the electrophysiological changes were the result of secondary activation of Ca2+-sensitive channels. PCP-R cells contain two Ca2+-activated K+ channels, the small conductance 2 (SK2) and the intermediate conductance (IK) channels. Based on inhibitor studies, the former is not involved in the TRPV4-mediated electrophysiological changes whereas one of the three isoforms of the IK channel (KCNN4c) may play a role in the apical secretion of K+. Blocking the activity of this IK isoform with TRAM34 inhibited the TRPV4-mediated change in net transepithelial ion flux and the increased conductance. These studies implicate TRPV4 as a hub protein in the control of CSF production through stimulation by multiple effectors resulting in transepithelial ion and subsequent water movement.


Assuntos
Plexo Corióideo/metabolismo , Células Epiteliais/metabolismo , Potenciais da Membrana/fisiologia , Canais de Cátion TRPV/metabolismo , Animais , Cálcio/metabolismo , Linhagem Celular , Plexo Corióideo/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Leucina/análogos & derivados , Leucina/farmacologia , Isoformas de Proteínas/metabolismo , Sulfonamidas/farmacologia , Suínos
17.
J Biochem ; 164(3): 205-213, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-29701803

RESUMO

Idiopathic normal pressure hydrocephalus (iNPH) is a dementia-inducing disorder. Primary cause of iNPH is speculated to be a reduction of cerebrospinal fluid (CSF) absorption, which secondarily induces hydrocephalus, compression of brain, and reduction of CSF production. Patients are treated by surgically inserting a shunt to deliver excess CSF to the abdominal cavity. The prognosis for cognitive improvement after shunt surgery has been difficult to predict. We therefore investigated various CSF proteins, hoping to find a biomarker predictive of cognitive performance one to two years after shunt surgery. CSF proteins of 34 iNPH and 15 non-iNPH patients were analysed by Western blotting, revealing two glycan isoforms of transferrin (Tf); 'brain-type' Tf with N-acetylglucosaminylated glycans and 'serum-type' Tf with α2, 6-sialylated glycans. Brain-type Tf levels decreased in iNPH but rapidly returned to normal levels within 1-3 months after shunt surgery. This change was positively correlated with recovery from dementia, per Mini-Mental State Examination and Frontal Assessment Battery scores at 11.8 ± 7.7 months post-operation, suggesting that brain-type Tf is a prognostic marker for recovery from dementia after shunt surgery for iNPH. Histochemical staining with anti-Tf antibody and an N-acetylglucosamine-binding lectin suggests that brain-type Tf is secreted from choroid plexus, CSF-producing tissue.


Assuntos
Biomarcadores/líquido cefalorraquidiano , Encéfalo/metabolismo , Transtornos Cognitivos/reabilitação , Hidrocefalia de Pressão Normal/cirurgia , Transferrina/líquido cefalorraquidiano , Idoso , Western Blotting , Estudos de Casos e Controles , Plexo Corióideo/metabolismo , Feminino , Humanos , Hidrocefalia de Pressão Normal/metabolismo , Hidrocefalia de Pressão Normal/psicologia , Masculino , Polissacarídeos/metabolismo , Prognóstico
18.
J Alzheimers Dis ; 62(4): 1691-1702, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29614677

RESUMO

BACKGROUND: On target 18F-Flortaucipir (FTP) binding of Alzheimer's disease tau aggregates and off-target binding of melanocytes have been demonstrated with autoradiography. OBJECTIVE: We aimed to investigate the hypothesis that if binding in choroid plexus (CP) is due to melanocytes, the signal would be elevated in Black/African American (B/AA) compared to White (W) participants. In addition, we examined whether CP signal affects measurements in adjacent regions, and whether correcting for spill-in effects has an influence on associations between hippocampus (HC) FTP and amyloid or cognition. METHODS: FTP race differences in 147 Harvard Aging Brain Study participants (23 B/AA, 124W) were examined in CP, HC, HC covaried for CP, amygdala, inferior temporal gyrus, entorhinal cortex, and fusiform regions. Associations between CP FTP and other regions-of-interest (ROIs) were probed to assess spill-in effects. A statistical regression approach to attenuate CP spill-in was tested by relating adjusted HC SUVR residuals and unadjusted HC SUVR to race, cognition and amyloid. All analyses were covaried for age, sex, education and amyloid deposition, and Bonferroni-corrected for multiple comparisons. RESULTS: B/AA individuals had elevated CP and HC SUVR (p < 0.007), whereas other ROI SUVR and HC SUVR covaried for CP SUVR did not show race differences (p > 0.05). CP SUVR was associated with HC SUVR (p < 10-14), but with no other ROI SUVR (p > 0.05). When adjusting HC SUVR for CP SUVR, no race differences in residual HC SUVR were detected, and relationships with amyloid and memory became apparent. CONCLUSION: Melanocyte FTP binding may account partially for high CP signal. This off-target binding affects mainly HC FTP measurements, which should be interpreted with caution.


Assuntos
Afro-Americanos , Carbolinas , Plexo Corióideo/metabolismo , Grupo com Ancestrais do Continente Europeu , Hipocampo/metabolismo , Compostos Radiofarmacêuticos , Idoso , Compostos de Anilina , Mapeamento Encefálico , Plexo Corióideo/diagnóstico por imagem , Feminino , Hipocampo/diagnóstico por imagem , Humanos , Estudos Longitudinais , Imagem por Ressonância Magnética , Masculino , Melanócitos/metabolismo , Tomografia por Emissão de Pósitrons , Tiazóis
19.
J Neurosci ; 38(14): 3466-3479, 2018 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-29507144

RESUMO

Exposure of the developing brain to toxins, drugs, or deleterious endogenous compounds during the perinatal period can trigger alterations in cell division, migration, differentiation, and synaptogenesis, leading to lifelong neurological impairment. The brain is protected by cellular barriers acting through multiple mechanisms, some of which are still poorly explored. We used a combination of enzymatic assays, live tissue fluorescence microscopy, and an in vitro cellular model of the blood-CSF barrier to investigate an enzymatic detoxification pathway in the developing male and female rat brain. We show that during the early postnatal period the choroid plexus epithelium forming the blood-CSF barrier and the ependymal cell layer bordering the ventricles harbor a high detoxifying capacity that involves glutathione S-transferases. Using a functional knock-down rat model for choroidal glutathione conjugation, we demonstrate that already in neonates, this metabolic pathway efficiently prevents the penetration of blood-borne reactive compounds into CSF. The versatility of the protective mechanism results from the multiplicity of the glutathione S-transferase isoenzymes, which are differently expressed between the choroidal epithelium and the ependyma. The various isoenzymes display differential substrate specificities, which greatly widen the spectrum of molecules that can be inactivated by this pathway. In conclusion, the blood-CSF barrier and the ependyma are identified as key cellular structures in the CNS to protect the brain fluid environment from different chemical classes of potentially toxic compounds during the postnatal period. This metabolic neuroprotective function of brain interfaces ought to compensate for the liver postnatal immaturity.SIGNIFICANCE STATEMENT Brain homeostasis requires a stable and controlled internal environment. Defective brain protection during the perinatal period can lead to lifelong neurological impairment. We demonstrate that the choroid plexus forming the blood-CSF barrier is a key player in the protection of the developing brain. Glutathione-dependent enzymatic metabolism in the choroidal epithelium inactivates a broad spectrum of noxious compounds, efficiently preventing their penetration into the CSF. A second line of detoxification is located in the ependyma separating the CSF from brain tissue. Our study reveals a novel facet of the mechanisms by which the brain is protected at a period of high vulnerability, at a time when the astrocytic network is still immature and liver xenobiotic metabolism is limited.


Assuntos
Barreira Hematoencefálica/metabolismo , Glutationa Transferase/metabolismo , Glutationa/metabolismo , Animais , Barreira Hematoencefálica/crescimento & desenvolvimento , Plexo Corióideo/crescimento & desenvolvimento , Plexo Corióideo/metabolismo , Epêndima/crescimento & desenvolvimento , Epêndima/metabolismo , Feminino , Radicais Livres/sangue , Radicais Livres/líquido cefalorraquidiano , Glutationa/sangue , Glutationa/líquido cefalorraquidiano , Masculino , Ratos , Ratos Sprague-Dawley
20.
Folia Morphol (Warsz) ; 77(4): 642-648, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29569703

RESUMO

BACKGROUND: Traumatic brain injury (TBI) is in part associated with the disruption of the blood-brain barrier. In this study, we analysed the histopathological changes in E-cadherin and vascular endothelial growth factor (VEGF) expression after TBI in rats. MATERIALS AND METHODS: The rats were divided into two groups as the control and the trauma groups. Sprague-Dawley rats were subjected to TBI with a weight-drop device using 300 g/1 m weight-height impact. After 5 days of TBI, blood samples were taken under ketamine hydroxide anaesthesia and biochemical analyses were performed. The control and trauma groups were compared in terms of biochemical values. RESULTS: There was no change in glutathione (GSH) levels and blood-brain barier permeability. However, malondialdehyde (MDA) and myeloperoxidase (MPO) activity levels increased in the trauma group. In the histopathological examination, choroid plexus in the lateral ventricle, near the pia mater membrane, was removed. In the traumatic group, some of epithelial cells were hyperplasic. Some of them were peeled off the apical surface and had local degeneration. CONCLUSIONS: In addition, we observed congestion in capillary vessels and mononuclear cell infiltration around the vessels. After TBI, the increase in VEGF levels, vascular permeability, and interaction with VEGF receptors in endothelial cells lead to oedema of the vessel wall. On the other hand, E-cadherin expression decreased in the tight-junction structures between epithelial cells and basal membrane, resulting in an increase in cerebrospinal fluid in the intervillous area.


Assuntos
Barreira Hematoencefálica , Lesões Encefálicas Traumáticas , Plexo Corióideo , Ventrículos Laterais , Animais , Barreira Hematoencefálica/metabolismo , Barreira Hematoencefálica/patologia , Lesões Encefálicas Traumáticas/metabolismo , Lesões Encefálicas Traumáticas/patologia , Caderinas/metabolismo , Permeabilidade Capilar , Plexo Corióideo/metabolismo , Plexo Corióideo/patologia , Imuno-Histoquímica , Ventrículos Laterais/patologia , Masculino , Ratos , Ratos Sprague-Dawley , Ratos Wistar , Receptores de Fatores de Crescimento do Endotélio Vascular/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo
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