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1.
Nat Commun ; 12(1): 1423, 2021 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-33658509

RESUMO

In the mammalian hippocampus, adult-born granule cells (abGCs) contribute to the function of the dentate gyrus (DG). Disruption of the DG circuitry causes spontaneous recurrent seizures (SRS), which can lead to epilepsy. Although abGCs contribute to local inhibitory feedback circuitry, whether they are involved in epileptogenesis remains elusive. Here, we identify a critical window of activity associated with the aberrant maturation of abGCs characterized by abnormal dendrite morphology, ectopic migration, and SRS. Importantly, in a mouse model of temporal lobe epilepsy, silencing aberrant abGCs during this critical period reduces abnormal dendrite morphology, cell migration, and SRS. Using mono-synaptic tracers, we show silencing aberrant abGCs decreases recurrent CA3 back-projections and restores proper cortical connections to the hippocampus. Furthermore, we show that GABA-mediated amplification of intracellular calcium regulates the early critical period of activity. Our results demonstrate that aberrant neurogenesis rewires hippocampal circuitry aggravating epilepsy in mice.


Assuntos
Epilepsia/fisiopatologia , Hipocampo/fisiopatologia , Neurogênese/fisiologia , Animais , Cálcio/metabolismo , Clozapina/análogos & derivados , Clozapina/farmacologia , Modelos Animais de Doenças , Eletroencefalografia , Epilepsia do Lobo Temporal/fisiopatologia , Feminino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neurogênese/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Pilocarpina/farmacologia , Retroviridae/genética , Convulsões/fisiopatologia , Ácido gama-Aminobutírico/metabolismo
2.
Nat Commun ; 12(1): 662, 2021 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-33510165

RESUMO

Dynamic assembly and disassembly of primary cilia controls embryonic development and tissue homeostasis. Dysregulation of ciliogenesis causes human developmental diseases termed ciliopathies. Cell-intrinsic regulatory mechanisms of cilia disassembly have been well-studied. The extracellular cues controlling cilia disassembly remain elusive, however. Here, we show that lysophosphatidic acid (LPA), a multifunctional bioactive phospholipid, acts as a physiological extracellular factor to initiate cilia disassembly and promote neurogenesis. Through systematic analysis of serum components, we identify a small molecular-LPA as the major driver of cilia disassembly. Genetic inactivation and pharmacological inhibition of LPA receptor 1 (LPAR1) abrogate cilia disassembly triggered by serum. The LPA-LPAR-G-protein pathway promotes the transcription and phosphorylation of cilia disassembly factors-Aurora A, through activating the transcription coactivators YAP/TAZ and calcium/CaM pathway, respectively. Deletion of Lpar1 in mice causes abnormally elongated cilia and decreased proliferation in neural progenitor cells, thereby resulting in defective neurogenesis. Collectively, our findings establish LPA as a physiological initiator of cilia disassembly and suggest targeting the metabolism of LPA and the LPA pathway as potential therapies for diseases with dysfunctional ciliogenesis.


Assuntos
Cílios/efeitos dos fármacos , Lisofosfolipídeos/farmacologia , Neurogênese/efeitos dos fármacos , Epitélio Pigmentado da Retina/efeitos dos fármacos , Transdução de Sinais , Animais , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Cílios/genética , Cílios/metabolismo , Células HEK293 , Proteínas Heterotriméricas de Ligação ao GTP/metabolismo , Humanos , Lisofosfolipídeos/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células-Tronco Neurais/citologia , Células-Tronco Neurais/efeitos dos fármacos , Células-Tronco Neurais/metabolismo , Neurogênese/genética , Ligação Proteica , Interferência de RNA , Receptores de Ácidos Lisofosfatídicos/genética , Receptores de Ácidos Lisofosfatídicos/metabolismo , Epitélio Pigmentado da Retina/citologia , Epitélio Pigmentado da Retina/metabolismo
3.
Methods Mol Biol ; 2258: 151-169, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33340360

RESUMO

Self-assembling brain spheroids derived from human stem cells closely emulate the tangled connectivity of the human brain, recapitulate aspects of organized tissue structure, and are relatively easy to manipulate compared to other existing three-dimensional (3D) cellular models. However, current platforms generate heterogeneously sized and short-lived spheroids, which do not robustly and reproducibly model human brain development and diseases. Here, we present a method to generate large-scale arrays of homogeneously sized 3D brain spheroids derived from human-induced pluripotent stem cells (hiPSCs) or immortalized neural progenitor cells to recapitulate Alzheimer's disease (AD) pathology in vitro. When embedded in extracellular matrix, these brain spheroids develop extensive outward projection of neurites and form networks, which are mediated by thick bundles of dendrites. This array facilitates cost-effective, high-throughput drug screening and mechanistic studies to better understand human brain development and neurodegenerative conditions, such as AD .


Assuntos
Células-Tronco Pluripotentes Induzidas/fisiologia , Células-Tronco Neurais/fisiologia , Neurogênese , Neurônios/fisiologia , Engenharia Tecidual , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Técnicas de Cultura de Células , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Ensaios de Triagem em Larga Escala , Humanos , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas/ultraestrutura , Microscopia Eletrônica de Varredura , Proteínas do Tecido Nervoso/metabolismo , Células-Tronco Neurais/efeitos dos fármacos , Células-Tronco Neurais/ultraestrutura , Neurogênese/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/ultraestrutura , Organoides
4.
Chemosphere ; 262: 128045, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182117

RESUMO

The vulnerability to environmental insults is heightened at early stages of development. However, the neurotoxic potential of bisphenol A (BPA) and bisphenol S (BPS) at developmental windows remains unclear. To investigate the mechanisms mediating the developmental neurotoxicity, zebrafish embryos were treated with 0.01, 0.03, 0.01, 0.3, 1 µM BPA/BPS. Also, we used Tg(HuC:GFP) zebrafish to investigate whether BPA/BPS could induce neuron development. The reduction in body length, and increased heart rate were significant in 0.3 and 1 µM BPA/BPS groups. The green fluorescence protein (GFP) intensity increased at 72 hpf and 120 hpf in Tg(HuC:GFP) larvae which was consistent with the increased mRNA expression of elval3 following BPS treatments, an indication of the plausible effect of BPS on embryonic neuron development. Additionally, BPA/BPS treatments elicited hyperactivity and reduced static time in zebrafish larvae, suggesting behavioral alterations. Moreover, qRT-PCR results showed that BPA and BPS could interfere with the normal expression of development-related genes vegfa, wnt8a, and mstn1 at the developmental stages. The expression of neurodevelopment-related genes (ngn1, elavl3, gfap, α1-tubulin, mbp, and gap43) were significantly upregulated in BPA and BPS treatments, except for the remarkable downregulation of mbp and gfap elicited by BPA at 48 (0.03 µM) and 120 hpf (0.3 µM) respectively; ngn1 at 48 hpf for 0.1 µM BPS. Overall, our results highlighted that embryonic exposure to low concentrations of BPA/BPS could be deleterious to the central nervous system development and elicit behavioral abnormalities in zebrafish at developmental stages.


Assuntos
Compostos Benzidrílicos/toxicidade , Embrião não Mamífero/efeitos dos fármacos , Desenvolvimento Embrionário/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Fenóis/toxicidade , Sulfonas/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra , Animais , Embrião não Mamífero/metabolismo , Larva/efeitos dos fármacos , Larva/metabolismo , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/metabolismo
5.
Nat Commun ; 11(1): 6363, 2020 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-33311466

RESUMO

Depression is the leading cause of disability worldwide. Recent observations have revealed an association between mood disorders and alterations of the intestinal microbiota. Here, using unpredictable chronic mild stress (UCMS) as a mouse model of depression, we show that UCMS mice display phenotypic alterations, which could be transferred from UCMS donors to naïve recipient mice by fecal microbiota transplantation. The cellular and behavioral alterations observed in recipient mice were accompanied by a decrease in the endocannabinoid (eCB) signaling due to lower peripheral levels of fatty acid precursors of eCB ligands. The adverse effects of UCMS-transferred microbiota were alleviated by selectively enhancing the central eCB or by complementation with a strain of the Lactobacilli genus. Our findings provide a mechanistic scenario for how chronic stress, diet and gut microbiota generate a pathological feed-forward loop that contributes to despair behavior via the central eCB system.


Assuntos
Comportamento Animal , Depressão/complicações , Endocanabinoides/farmacologia , Microbioma Gastrointestinal/fisiologia , Estresse Psicológico/complicações , Animais , Modelos Animais de Doenças , Ácidos Graxos/metabolismo , Transplante de Microbiota Fecal , Lactobacillus/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurogênese/efeitos dos fármacos
6.
J Toxicol Sci ; 45(10): 639-650, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33012732

RESUMO

Bisphenol A (BPA), an endocrine disruptor with estrogenic effects, is widely used as a raw material for manufacturing polycarbonate plastic and epoxy resins. Prenatal and postnatal exposure to BPA affects brain morphogenesis. However, the effects of prenatal and postnatal BPA exposure on postnatal neurogenesis in mice are poorly understood. In this study, we developed a mouse model of prenatal and postnatal BPA exposure and analyzed its effects on hippocampal neurogenesis. The hippocampal dentate gyrus is vulnerable to chemical exposure, as neurogenesis continues in this region even after birth. Our results showed that in mice, prenatal and postnatal BPA exposure decreased the number of type-1, 2a, 2b, and 3 neural progenitor cells, as well as in granule cells, in the hippocampal dentate gyrus on postnatal days 16 and 70. The effect of prenatal and postnatal BPA exposure on neural progenitors were affected at all differentiation stages. In addition, prenatal and postnatal BPA exposure affects the maintenance of long-term memory on postnatal day 70. Our results suggest that neurodevelopmental toxicity due to prenatal and postnatal BPA exposure might affect postnatal morphogenesis and functional development of the hippocampal dentate gyrus.


Assuntos
Animais Recém-Nascidos , Compostos Benzidrílicos/toxicidade , Giro Denteado/efeitos dos fármacos , Disruptores Endócrinos/toxicidade , Hipocampo/efeitos dos fármacos , Exposição Materna/efeitos adversos , Troca Materno-Fetal/efeitos dos fármacos , Células-Tronco Neurais/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Fenóis/toxicidade , Animais , Diferenciação Celular/efeitos dos fármacos , Feminino , Masculino , Camundongos , Modelos Animais , Gravidez
7.
PLoS One ; 15(9): e0233477, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32925933

RESUMO

Emerging evidence indicates that a strong relationship exists between brain regenerative therapies and nutrition. Early life nutrition plays an important role during embryonic brain development, and there are clear consequences to an imbalance in nutritional factors on both the production and survival of mature neuronal populations and the infant's risk of diseases in later life. Our research and that of others suggest that vitamins play a fundamental role in the formation of neurons and their survival. There is a growing body of evidence that nicotinamide, the water-soluble amide form of vitamin B3, is implicated in the conversion of pluripotent stem cells to clinically relevant cells for regenerative therapies. This study investigated the ability of nicotinamide to promote the development of mature catecholaminergic neuronal populations (associated with Parkinson's disease) from mouse embryonic stem cells, as well as investigating the underlying mechanisms of nicotinamide's action. Nicotinamide selectively enhanced the production of tyrosine hydroxylase-expressing neurons and serotonergic neurons from mouse embryonic stem cell cultures (Sox1GFP knock-in 46C cell line). A 5-Ethynyl-2´-deoxyuridine (EdU) assay ascertained that nicotinamide, when added in the initial phase, reduced cell proliferation. Nicotinamide drove tyrosine hydroxylase-expressing neuron differentiation as effectively as an established cocktail of signalling factors, reducing the proliferation of neural progenitors and accelerating neuronal maturation, neurite outgrowth and neurotransmitter expression. These novel findings show that nicotinamide enhanced and enriched catecholaminergic differentiation and inhibited cell proliferation by directing cell cycle arrest in mouse embryonic stem cell cultures, thus driving a critical neural proliferation-to-differentiation switch from neural progenitors to neurons. Further research into the role of vitamin metabolites in embryogenesis will significantly advance cell-based regenerative medicine, and help realize their role as crucial developmental signalling molecules in brain development.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Neurais/citologia , Neurogênese/efeitos dos fármacos , Niacinamida/farmacologia , Animais , Células Cultivadas , Camundongos , Neurônios/citologia
8.
PLoS One ; 15(7): e0235232, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32735618

RESUMO

The tamoxifen-dependent Cre/lox system in transgenic mice has become an important research tool across all scientific disciplines for manipulating gene expression in specific cell types. In these mouse models, Cre-recombination is not induced until tamoxifen is administered, which allows researchers to have temporal control of genetic modifications. Interestingly, tamoxifen has been identified as a potential therapy for spinal cord injury (SCI) and traumatic brain injury patients due to its neuroprotective properties. It is also reparative in that it stimulates oligodendrocyte differentiation and remyelination after toxin-induced demyelination. However, it is unknown whether tamoxifen is neuroprotective and neuroreparative when administration is delayed after SCI. To properly interpret data from transgenic mice in which tamoxifen treatment is delayed after SCI, it is necessary to identify the effects of tamoxifen alone on anatomical and functional recovery. In this study, female and male mice received a moderate mid-thoracic spinal cord contusion. Mice were then gavaged with corn oil or a high dose of tamoxifen from 19-22 days post-injury, and sacrificed 42 days post-injury. All mice underwent behavioral testing for the duration of the study, which revealed that tamoxifen treatment did not impact hindlimb motor recovery. Similarly, histological analyses revealed that tamoxifen had no effect on white matter sparing, total axon number, axon sprouting, glial reactivity, cell proliferation, oligodendrocyte number, or myelination, but tamoxifen did decrease the number of neurons in the dorsal and ventral horn. Semi-thin sections confirmed that axon demyelination and remyelination were unaffected by tamoxifen. Sex-specific responses to tamoxifen were also assessed, and there were no significant differences between female and male mice. These data suggest that delayed tamoxifen administration after SCI does not change functional recovery or improve tissue sparing in female or male mice.


Assuntos
Neurônios/efeitos dos fármacos , Remielinização/efeitos dos fármacos , Traumatismos da Medula Espinal/tratamento farmacológico , Tamoxifeno/administração & dosagem , Tempo para o Tratamento , Administração Oral , Animais , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Feminino , Membro Posterior/inervação , Membro Posterior/fisiologia , Humanos , Masculino , Camundongos , Atividade Motora/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Oligodendroglia/efeitos dos fármacos , Recuperação de Função Fisiológica/efeitos dos fármacos , Fatores Sexuais , Corno Dorsal da Medula Espinal/citologia , Corno Dorsal da Medula Espinal/efeitos dos fármacos , Corno Ventral da Medula Espinal/citologia , Corno Ventral da Medula Espinal/efeitos dos fármacos
9.
Proc Natl Acad Sci U S A ; 117(32): 19578-19589, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32727894

RESUMO

The CreER/LoxP system is widely accepted to track neural lineages and study gene functions upon tamoxifen (TAM) administration. We have observed that prenatal TAM treatment caused high rates of delayed delivery and fetal mortality. This substance could produce undesired results, leading to data misinterpretation. Here, we report that administration of TAM during early stages of cortical neurogenesis promoted precocious neural differentiation, while it inhibited neural progenitor cell (NPC) proliferation. The TAM-induced inhibition of NPC proliferation led to deficits in cortical neurogenesis, dendritic morphogenesis, synaptic formation, and cortical patterning in neonatal and postnatal offspring. Mechanistically, by employing single-cell RNA-sequencing (scRNA-seq) analysis combined with in vivo and in vitro assays, we show TAM could exert these drastic effects mainly through dysregulating the Wnt-Dmrta2 signaling pathway. In adult mice, administration of TAM significantly attenuated NPC proliferation in both the subventricular zone and the dentate gyrus. This study revealed the cellular and molecular mechanisms for the adverse effects of TAM on corticogenesis, suggesting that care must be taken when using the TAM-induced CreER/LoxP system for neural lineage tracing and genetic manipulation studies in both embryonic and adult brains.


Assuntos
Encéfalo/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Efeitos Tardios da Exposição Pré-Natal/patologia , Tamoxifeno/efeitos adversos , Animais , Encéfalo/embriologia , Encéfalo/patologia , Diferenciação Celular , Proliferação de Células , Giro Denteado/efeitos dos fármacos , Giro Denteado/patologia , Feminino , Ventrículos Laterais/efeitos dos fármacos , Ventrículos Laterais/patologia , Camundongos , Células-Tronco Neurais/efeitos dos fármacos , Células-Tronco Neurais/patologia , Gravidez , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , RNA-Seq , Análise de Célula Única , Fatores de Transcrição/metabolismo , Via de Sinalização Wnt/efeitos dos fármacos
10.
Nat Med ; 26(8): 1285-1294, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32719487

RESUMO

We asked whether pharmacological stimulation of endogenous neural precursor cells (NPCs) may promote cognitive recovery and brain repair, focusing on the drug metformin, in parallel rodent and human studies of radiation injury. In the rodent cranial radiation model, we found that metformin enhanced the recovery of NPCs in the dentate gyrus, with sex-dependent effects on neurogenesis and cognition. A pilot double-blind, placebo-controlled crossover trial was conducted (ClinicalTrials.gov, NCT02040376) in survivors of pediatric brain tumors who had been treated with cranial radiation. Safety, feasibility, cognitive tests and MRI measures of white matter and the hippocampus were evaluated as endpoints. Twenty-four participants consented and were randomly assigned to complete 12-week cycles of metformin (A) and placebo (B) in either an AB or BA sequence with a 10-week washout period at crossover. Blood draws were conducted to monitor safety. Feasibility was assessed as recruitment rate, medication adherence and procedural adherence. Linear mixed modeling was used to examine cognitive and MRI outcomes as a function of cycle, sequence and treatment. We found no clinically relevant safety concerns and no serious adverse events associated with metformin. Sequence effects were observed for all cognitive outcomes in our linear mixed models. For the subset of participants with complete data in cycle 1, metformin was associated with better performance than placebo on tests of declarative and working memory. We present evidence that a clinical trial examining the effects of metformin on cognition and brain structure is feasible in long-term survivors of pediatric brain tumors and that metformin is safe to use and tolerable in this population. This pilot trial was not intended to test the efficacy of metformin for cognitive recovery and brain growth, but the preliminary results are encouraging and warrant further investigation in a large multicenter phase 3 trial.


Assuntos
Neoplasias Encefálicas/complicações , Disfunção Cognitiva/tratamento farmacológico , Metformina/administração & dosagem , Pediatria/tendências , Adolescente , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Sobreviventes de Câncer , Criança , Pré-Escolar , Cognição/efeitos dos fármacos , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/patologia , Método Duplo-Cego , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Metformina/efeitos adversos , Neurogênese/efeitos dos fármacos , Projetos Piloto , Resultado do Tratamento , Adulto Jovem
11.
Life Sci ; 258: 118071, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32673664

RESUMO

Many cancer patients treated with chemotherapy develop chemotherapy-induced cognitive impairment (CICI), often referred to as chemo-brain, which manifest during or post-treatment with variable degrees, onset and duration thereby affecting the patients' quality of life. Several chemotherapeutic agents have been studied to determine its possible association with cognitive impairment and to fully comprehend their contribution to CICI. A vast number of studies have emerged proposing several candidate underlying mechanisms and etiologies contributing to CICI such as direct neurotoxicity, BBB disruption, decreased hippocampal neurogenesis, white matter abnormalities, secondary neuro-inflammatory response and increased oxidative stress; however, the exact underlying mechanisms are still not well defined. This review summarizes CICI associated with most commonly used chemotherapeutic agents with emphasizes the possible underlying pathogenesis in both animal and clinical studies.


Assuntos
Antineoplásicos/efeitos adversos , Disfunção Cognitiva/induzido quimicamente , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Ensaios Clínicos como Assunto , Disfunção Cognitiva/imunologia , Disfunção Cognitiva/psicologia , Humanos , Neurogênese/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos
12.
J Neurosci ; 40(21): 4116-4129, 2020 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-32385093

RESUMO

The cellular and molecular basis of metaplasia and declining neurogenesis in the aging olfactory epithelium (OE) remains unknown. The horizontal basal cell (HBC) is a dormant tissue-specific stem cell presumed to only be forced into self-renewal and differentiation by injury. Here we analyze male and female mice and show that HBCs also are activated with increasing age as well as non-cell-autonomously by increased expression of the retinoic acid-degrading enzyme CYP26B1. Activating stimuli induce HBCs throughout OE to acquire a rounded morphology and express IP3R3, which is an inositol-1,4,5-trisphosphate receptor constitutively expressed in stem cells of the adjacent respiratory epithelium. Odor/air stimulates CYP26B1 expression in olfactory sensory neurons mainly located in the dorsomedial OE, which is spatially inverse to ventrolateral constitutive expression of the retinoic acid-synthesizing enzyme (RALDH1) in supporting cells. In ventrolateral OE, HBCs express low p63 levels and preferentially differentiate instead of self-renewing when activated. When activated by chronic CYP26B1 expression, repeated injury, or old age, ventrolateral HBCs diminish in number and generate a novel type of metaplastic respiratory cell that is RALDH- and secretes a mucin-like mucus barrier protein (FcγBP). Conversely, in the dorsomedial OE, CYP26B1 inhibits injury-induced and age-related replacement of RALDH- supporting cells with RALDH1+ ciliated respiratory cells. Collectively, these results support the concept that inositol-1,4,5-trisphosphate type 3 receptor signaling in HBCs, together with altered retinoic acid metabolism within the niche, promote HBC lineage commitment toward two types of respiratory cells that will maintain epithelial barrier function once the capacity to regenerate OE cells ceases.SIGNIFICANCE STATEMENT Little is known about signals that activate dormant stem cells to self-renew and regenerate odor-detecting neurons and other olfactory cell types after loss due to injury, infection, or toxin exposure in the nose. It is also unknown why the stem cells do not prevent age-dependent decline of odor-detecting neurons. We show that (1) stem cells are kept inactive by the vitamin A derivative retinoic acid, which is synthesized and degraded locally by olfactory cells; (2) old age as well as repeated injuries activate the stem cells and exhaust their potential to produce olfactory cells; and (3) exhausted stem cells alter the local retinoic acid metabolism and maintain the epithelial tissue barrier by generating airway cells instead of olfactory cells.


Assuntos
Envelhecimento/metabolismo , Isotretinoína/farmacologia , Células-Tronco Neurais/metabolismo , Neurônios Receptores Olfatórios/metabolismo , Ácido Retinoico 4 Hidroxilase/metabolismo , Animais , Feminino , Masculino , Metaplasia/metabolismo , Camundongos , Células-Tronco Neurais/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Neurogênese/fisiologia , Mucosa Olfatória/efeitos dos fármacos , Mucosa Olfatória/metabolismo , Neurônios Receptores Olfatórios/efeitos dos fármacos
13.
Ecotoxicol Environ Saf ; 200: 110733, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32450442

RESUMO

Paraquat (1,1'-dimethyl-4,4'-bipyridium dichloride, PQ), a non-selective and efficient herbicide, causes neuroinflammation, neurodegeneration and memory dysfunction. However, adverse effects of PQ on the neuroimmune interactions have rarely been investigated. Female adult C57/BL6 mice were divided into 3 groups and treated with PQ (intraperitoneal injection, 1 mg/kg or 5 mg/kg) or the vehicle (an equivalent volume of 0.9% saline) every two days, at day 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, for a total of 14 doses. We evaluated blood-brain barrier (BBB) integrity and PQ concentrations during the course of PQ exposure and tested interleukin-1ß (IL-1ß) concentrations in dentate gyrus (DG) after 28 days PQ exposure. In addition, memory function, neural stem cells (NSCs) proliferation, neurogenesis and microglia polarization were analyzed after PQ exposure. Furthermore, mice were intraperitoneal injections of anti-IL-1ß during 5 mg/kg PQ exposure to test the rule of IL-1ß. Blood-brain barrier (BBB) permeability and PQ concentrations increased gradually during PQ exposure (n = 6). Moreover, memory function, NSCs proliferation and neurogenesis were impaired after 5 mg/kg PQ exposure (n = 6). Further analyses revealed that 'classically' activated (M1) microglia and IL-1ß concentrations in DG were increased after 5 mg/kg PQ treatment (n = 6). Moreover, we found that neutralization of IL-1ß partly restored PQ-induced NSCs impairments and memory dysfunction (n = 6). In conclusion, our results revealed that PQ induced NSCs impairments and memory dysfunction in adult mice, which was related to the release of IL-1ß by M1-polarized microglia in DG. These findings may help understand the neurotoxic effect of PQ.


Assuntos
Giro Denteado/efeitos dos fármacos , Herbicidas/toxicidade , Interleucina-1beta/metabolismo , Neurogênese/efeitos dos fármacos , Paraquat/toxicidade , Animais , Barreira Hematoencefálica/efeitos dos fármacos , Giro Denteado/citologia , Feminino , Memória/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Microglia/efeitos dos fármacos , Células-Tronco Neurais/citologia , Células-Tronco Neurais/efeitos dos fármacos
14.
PLoS One ; 15(3): e0229892, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32231396

RESUMO

The specification of cell identity depends on the exposure of cells to sequences of bioactive ligands. All-trans retinoic acid (ATRA) affects neuronal development in the early stage, and it is involved in neuronal lineage reprogramming. We previously established a fibroblast-like dedifferentiated fat cells (DFATs) derived from highly homogeneous mature adipocytes, which are more suitable for the study of cellular reprogramming. Canine cognitive dysfunction is similar to human cognitive dysfunction, suggesting that dogs could be a pathological and pharmacological model for human neuronal diseases. However, the effect of ATRA on neuronal reprogramming in dogs has remained unclear. Therefore, in this study, we investigated the effect of ATRA on the neuronal reprogramming of canine DFATs. ATRA induced the expression of neuronal marker mRNA/protein. The neuron-like cells showed Ca2+ influx with depolarization (50 mM KCl; 84.75 ± 4.05%) and Na+ channel activation (50 µM veratridine; 96.02 ± 2.02%). Optical imaging of presynaptic terminal activity and detection of neurotransmitter release showed that the neuron-like cells exhibited the GABAergic neuronal property. Genome-wide RNA-sequencing analysis shows that the transcriptome profile of canine DFATs is effectively reprogrammed towards that of cortical interneuron lineage. Collectively, ATRA can produce functional GABAergic cortical interneuron-like cells from canine DFATs, exhibiting neuronal function with > 80% efficiency. We further demonstrated the contribution of JNK3 to ATRA-induced neuronal reprogramming in canine DFATs. In conclusion, the neuron-like cells from canine DFATs could be a powerful tool for translational research in cell transplantation therapy, in vitro disease modeling, and drug screening for neuronal diseases.


Assuntos
Desdiferenciação Celular/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Tretinoína/farmacologia , Animais , Diferenciação Celular/efeitos dos fármacos , Reprogramação Celular/efeitos dos fármacos , Cães , Neurogênese/genética , RNA Mensageiro/genética , Sinapses/efeitos dos fármacos , Sinapses/genética
15.
Nat Commun ; 11(1): 1914, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32313051

RESUMO

Obesity is associated with the activation of cellular responses, such as endoplasmic reticulum (ER) stress. Here, we show that leptin-deficient ob/ob mice display elevated hypothalamic ER stress as early as postnatal day 10, i.e., prior to the development of obesity in this mouse model. Neonatal treatment of ob/ob mice with the ER stress-relieving drug tauroursodeoxycholic acid (TUDCA) causes long-term amelioration of body weight, food intake, glucose homeostasis, and pro-opiomelanocortin (POMC) projections. Cells exposed to ER stress often activate autophagy. Accordingly, we report that in vitro induction of ER stress and neonatal leptin deficiency in vivo activate hypothalamic autophagy-related genes. Furthermore, genetic deletion of autophagy in pro-opiomelanocortin neurons of ob/ob mice worsens their glucose homeostasis, adiposity, hyperphagia, and POMC neuronal projections, all of which are ameliorated with neonatal TUDCA treatment. Together, our data highlight the importance of early life ER stress-autophagy pathway in influencing hypothalamic circuits and metabolic regulation.


Assuntos
Autofagia/fisiologia , Estresse do Retículo Endoplasmático/fisiologia , Metabolismo Energético/fisiologia , Hipotálamo/metabolismo , Leptina/metabolismo , Neurogênese/fisiologia , Adiposidade , Animais , Antivirais/farmacologia , Autofagia/efeitos dos fármacos , Autofagia/genética , Proteína 7 Relacionada à Autofagia/genética , Peso Corporal/efeitos dos fármacos , Peso Corporal/fisiologia , Colagogos e Coleréticos/farmacologia , Modelos Animais de Doenças , Ingestão de Alimentos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/genética , Comportamento Alimentar , Homeostase , Hiperfagia/metabolismo , Leptina/genética , Masculino , Doenças Metabólicas/genética , Doenças Metabólicas/metabolismo , Camundongos , Camundongos Endogâmicos , Camundongos Knockout , Neuroendocrinologia , Neurogênese/efeitos dos fármacos , Obesidade/metabolismo , Pró-Opiomelanocortina/metabolismo , Ácido Tauroquenodesoxicólico
16.
Sci Rep ; 10(1): 6596, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32313130

RESUMO

Enhancement of endogenous neurogenesis after ischemic stroke may improve functional recovery. We previously demonstrated that medium B, which is a combination with epidermal growth factor (EGF) and fibronectin, can promote neural stem/progenitor cell (NSPC) proliferation and migration. Here, we showed that medium B promoted proliferation and migration of cultured NSPCs onto various 3-dimentional structures. When rat cortical neurons with oxygen glucose deprivation (OGD) were co-cultured with NSPCs, medium B treatment increased neuronal viability and reduced cell apoptosis. In a rat model with transient middle cerebral artery occlusion (MCAO), post-insult intraventricular medium B treatment enhanced proliferation, migration, and neuronal differentiation of NSPCs and diminished cell apoptosis in the infarct brain. In cultured post-OGD neuronal cells and the infarct brain from MCAO rats, medium B treatment increased protein levels of Bcl-xL, Bcl-2, phospho-Akt, phospho-GSK-3ß, and ß-catenin and decreased the cleaved caspase-3 level, which may be associated with the effects of anti-apoptosis. Notably, intraventricular medium B treatment increased neuronal density, improved motor function and reduced infarct size in MCAO rats. In summary, medium B treatment results in less neuronal death and better functional outcome in both cellular and rodent models of ischemic stroke, probably via promotion of neurogenesis and reduction of apoptosis.


Assuntos
Apoptose , Isquemia Encefálica/tratamento farmacológico , Ventrículos Cerebrais/patologia , Fator de Crescimento Epidérmico/uso terapêutico , Fibronectinas/uso terapêutico , Neurogênese , Acidente Vascular Cerebral/tratamento farmacológico , Animais , Apoptose/efeitos dos fármacos , Isquemia Encefálica/complicações , Isquemia Encefálica/fisiopatologia , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ventrículos Cerebrais/fisiopatologia , Modelos Animais de Doenças , Fator de Crescimento Epidérmico/farmacologia , Fibronectinas/farmacologia , Glucose/deficiência , Infarto da Artéria Cerebral Média/complicações , Infarto da Artéria Cerebral Média/patologia , Infarto da Artéria Cerebral Média/fisiopatologia , Ventrículos Laterais/patologia , Ventrículos Laterais/fisiopatologia , Masculino , Células-Tronco Neurais/efeitos dos fármacos , Células-Tronco Neurais/ultraestrutura , Neurogênese/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/patologia , Oxigênio , Ratos Wistar , Recuperação de Função Fisiológica/efeitos dos fármacos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/fisiopatologia
17.
Life Sci ; 252: 117669, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32298740

RESUMO

Chronic social defeat stress (CSDS) is an ethologically relevant psychosocial stress animal model and has been widely used in depression studies. Ginsenoside Rg1 (Rg1) is the major active ingredients of ginseng with low toxicity and neuroprotective effects. The present study aims to investigate the antidepressant effects of Rg1 in CSDS mice and explore its molecular mechanism. We found that Rg1 (20 or 40 mg/kg, i.g.) administration significantly alleviated depressive-like behaviors caused by 4-week CSDS exposure, as measured by social interaction test and sucrose preference test, tail suspension test and forced swim test. Additionally, Rg1 treatment inhibited CSDS-induced production of IL-6, TNF-α and IL-1ß, decreased the expression of iNOS, COX2, and caspase-9 and -3, and inhibited microglial activation (Iba1) in the hippocampus. Rg1 was found to significantly downregulate p-JNK1/2 and p-P38 MAPK levels, upregulate p-ERK1/2 levels and inhibit the expression of phosphorylated NF-κB in the hippocampus. Meanwhile, Rg1 regulated SIRT1 and decreased the levels of acetylated p65 (ac-p65) in the hippocampus. Moreover, the reduction in adult hippocampal neurogenesis in CSDS mice was reversed by Rg1 treatment. In conclusion, our findings suggest that Rg1 prevents depressive-like behavior in CSDS-exposed mice, partially through the downregulation of hippocampal neuroinflammation and the upregulation of adult hippocampal neurogenesis and that these changes presumably occur through increased anti-inflammatory effects and the inhibition of proinflammatory cytokine and neurotoxic mediator expression and microglial activation, which is partly mediated by the regulation of the MAPK and SIRT1 signaling pathways and results in the inhibition of NF-κB transcriptional activity.


Assuntos
Antidepressivos/farmacologia , Depressão/prevenção & controle , Ginsenosídeos/farmacologia , Estresse Psicológico/tratamento farmacológico , Animais , Antidepressivos/administração & dosagem , Comportamento Animal/efeitos dos fármacos , Citocinas/metabolismo , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Ginsenosídeos/administração & dosagem , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Inflamação/tratamento farmacológico , Inflamação/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Neurogênese/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos
18.
J Nutr ; 150(6): 1631-1643, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32243527

RESUMO

BACKGROUND: The cognitive impairments that characterize Down syndrome (DS) have been attributed to brain hypocellularity due to neurogenesis impairment during fetal stages. Thus, enhancing prenatal neurogenesis in DS could prevent or reduce some of the neuromorphological and cognitive defects found in postnatal stages. OBJECTIVES: As fatty acids play a fundamental role in morphogenesis and brain development during fetal stages, in this study, we aimed to enhance neurogenesis and the cognitive abilities of the Ts65Dn (TS) mouse model of DS by administering oleic or linolenic acid. METHODS: In total, 85 pregnant TS females were subcutaneously treated from Embryonic Day (ED) 10 until Postnatal Day (PD) 2 with oleic acid (400 mg/kg), linolenic acid (500 mg/kg), or vehicle. All analyses were performed on their TS and Control (CO) male and female progeny. At PD2, we evaluated the short-term effects of the treatments on neurogenesis, cellularity, and brain weight, in 40 TS and CO pups. A total of 69 TS and CO mice were used to test the long-term effects of the prenatal treatments on cognition from PD30 to PD45, and on neurogenesis, cellularity, and synaptic markers, at PD45. Data were compared by ANOVAs. RESULTS: Prenatal administration of oleic or linolenic acid increased the brain weight (+36.7% and +45%, P < 0.01), the density of BrdU (bromodeoxyuridine)- (+80% and +115%; P < 0.01), and DAPI (4',6-diamidino-2-phenylindole)-positive cells (+64% and +22%, P < 0.05) of PD2 TS mice with respect to the vehicle-treated TS mice. Between PD30 and PD45, TS mice prenatally treated with oleic or linolenic acid showed better cognitive abilities (+28% and +25%, P < 0.01) and a higher density of the postsynaptic marker PSD95 (postsynaptic density protein 95) (+65% and +44%, P < 0.05) than the vehicle-treated TS animals. CONCLUSION: The beneficial cognitive and neuromorphological effects induced by oleic or linolenic acid in TS mice suggest that they could be promising pharmacotherapies for DS-associated cognitive deficits.


Assuntos
Síndrome de Down/fisiopatologia , Exposição Materna , Ácido Oleico/administração & dosagem , Ácido alfa-Linoleico/administração & dosagem , Animais , Peso Corporal/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Cognição/efeitos dos fármacos , Modelos Animais de Doenças , Síndrome de Down/patologia , Feminino , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neurogênese/efeitos dos fármacos , Ácido Oleico/farmacologia , Tamanho do Órgão/efeitos dos fármacos , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Ácido alfa-Linoleico/farmacologia
19.
Toxicology ; 439: 152443, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32278789

RESUMO

Stavudine is an anti-AIDS drug widely used to prevent HIV transmission from pregnant mothers to the fetuses in underdeveloped countries for its low price. However, there is still a controversy on whether stavudine affects embryo development. In the current study, embryotoxicity of stavudine was evaluated using cultured mouse embryos with the concentrations: 5, 10, 15 µM and vehicle control. The data indicated that the effect of stavudine was dose-dependent at early neurogenesis. Stavudine exposure reduced somite numbers, yolk sac diameter, crown-rump length, and increased the rate of embryonic degeneration compared with the control. We chose the lowest but clearly toxic concentration: 5 µM to investigate the molecular mechanisms of the damage. At the molecular level, stavudine produced DNA damage, increased the levels of the phospho-CHK1 and cleaved-caspase-3, and decreased the expression level of proliferating cell nuclear antigen. These changes indicated that stavudine caused a coordinated DNA damage response, inhibited cell proliferation, and induced apoptosis in the embryos. Collectively these results suggest that stavudine exposure disturbs the embryonic development, and its use in pregnant mothers should be re-examined.


Assuntos
Anormalidades Induzidas por Medicamentos/patologia , Fármacos Anti-HIV/toxicidade , Apoptose/efeitos dos fármacos , Estavudina/toxicidade , Animais , Caspase 3/efeitos dos fármacos , Contagem de Células , Proliferação de Células/efeitos dos fármacos , Quinase 1 do Ponto de Checagem/efeitos dos fármacos , Dano ao DNA , Desenvolvimento Embrionário/efeitos dos fármacos , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Neurogênese/efeitos dos fármacos , Gravidez , Antígeno Nuclear de Célula em Proliferação/efeitos dos fármacos , Saco Vitelino/efeitos dos fármacos , Saco Vitelino/patologia
20.
Eur J Histochem ; 64(2)2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-32236088

RESUMO

Schwann cells (SC) are characterized by a remarkable plasticity that enables them to promptly respond to nerve injury promoting axonal regeneration. In peripheral nerves after damage SC convert to a repair-promoting phenotype activating a sequence of supportive functions that drive myelin clearance, prevent neuronal death, and help axon growth and guidance. Regeneration of peripheral nerves after damage correlates inversely with thrombin levels. Thrombin is not only the key regulator of the coagulation cascade but also a protease with hormone-like activities that affects various cells of the central and peripheral nervous system mainly through the protease-activated receptor 1 (PAR1). Aim of the present study was to investigate if and how thrombin could affect the axon supportive functions of SC. In particular, our results show that the activation of PAR1 in rat SC cultures with low levels of thrombin or PAR1 agonist peptides induces the release of molecules, which favor neuronal survival and neurite elongation. Conversely, the stimulation of SC with high levels of thrombin or PAR1 agonist peptides drives an opposite effect inducing SC to release factors that inhibit the extension of neurites. Moreover, high levels of thrombin administered to sciatic nerve ex vivo explants induce a dramatic change in SC morphology causing disappearance of the Cajal bands, enlargement of the Schmidt-Lanterman incisures and calcium-mediated demyelination of the paranodes. Our results indicate thrombin as a novel modulator of SC plasticity potentially able to favor or inhibit SC pro-regenerative properties according to its level at the site of lesion.


Assuntos
Neurogênese/efeitos dos fármacos , Nós Neurofibrosos/efeitos dos fármacos , Células de Schwann/efeitos dos fármacos , Trombina/farmacologia , Animais , Cálcio/metabolismo , Feminino , Masculino , Neuritos/efeitos dos fármacos , Células PC12 , Pirróis/farmacologia , Quinazolinas/farmacologia , Ratos , Ratos Wistar , Receptor PAR-1/metabolismo , Nervo Isquiático/efeitos dos fármacos , Tapsigargina/farmacologia
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