Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 369.722
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Cell ; 173(5): 1280-1292.e18, 2018 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-29681453

RESUMO

The mammalian hippocampus, comprised of serially connected subfields, participates in diverse behavioral and cognitive functions. It has been postulated that parallel circuitry embedded within hippocampal subfields may underlie such functional diversity. We sought to identify, delineate, and manipulate this putatively parallel architecture in the dorsal subiculum, the primary output subfield of the dorsal hippocampus. Population and single-cell RNA-seq revealed that the subiculum can be divided into two spatially adjacent subregions associated with prominent differences in pyramidal cell gene expression. Pyramidal cells occupying these two regions differed in their long-range inputs, local wiring, projection targets, and electrophysiological properties. Leveraging gene-expression differences across these regions, we use genetically restricted neuronal silencing to show that these regions differentially contribute to spatial working memory. This work provides a coherent molecular-, cellular-, circuit-, and behavioral-level demonstration that the hippocampus embeds structurally and functionally dissociable streams within its serial architecture.


Assuntos
Hipocampo/metabolismo , Animais , Axônios/fisiologia , Comportamento Animal , Encéfalo/metabolismo , Encéfalo/patologia , Feminino , Hipocampo/citologia , Técnicas In Vitro , Masculino , Aprendizagem em Labirinto , Memória de Curto Prazo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Técnicas de Patch-Clamp , Análise de Componente Principal , Células Piramidais/citologia , Células Piramidais/metabolismo , Análise de Sequência de RNA , Transcriptoma
2.
Cell ; 174(6): 1586-1598.e12, 2018 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-30100188

RESUMO

Cancer immunotherapies have shown substantial clinical activity for a subset of patients with epithelial cancers. Still, technological platforms to study cancer T-cell interactions for individual patients and understand determinants of responsiveness are presently lacking. Here, we establish and validate a platform to induce and analyze tumor-specific T cell responses to epithelial cancers in a personalized manner. We demonstrate that co-cultures of autologous tumor organoids and peripheral blood lymphocytes can be used to enrich tumor-reactive T cells from peripheral blood of patients with mismatch repair-deficient colorectal cancer and non-small-cell lung cancer. Furthermore, we demonstrate that these T cells can be used to assess the efficiency of killing of matched tumor organoids. This platform provides an unbiased strategy for the isolation of tumor-reactive T cells and provides a means by which to assess the sensitivity of tumor cells to T cell-mediated attack at the level of the individual patient.


Assuntos
Leucócitos Mononucleares/citologia , Linfócitos T/imunologia , Idoso , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Técnicas de Cultura de Células , Técnicas de Cocultura , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Feminino , Humanos , Técnicas In Vitro , Interferon gama/farmacologia , Leucócitos Mononucleares/metabolismo , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Ativação Linfocitária/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Linfócitos T/citologia , Linfócitos T/efeitos dos fármacos , Células Tumorais Cultivadas
3.
Nat Immunol ; 21(3): 274-286, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32066947

RESUMO

Human immunodeficiency virus 1 (HIV-1) infection is associated with heightened inflammation and excess risk of cardiovascular disease, cancer and other complications. These pathologies persist despite antiretroviral therapy. In two independent cohorts, we found that innate lymphoid cells (ILCs) were depleted in the blood and gut of people with HIV-1, even with effective antiretroviral therapy. ILC depletion was associated with neutrophil infiltration of the gut lamina propria, type 1 interferon activation, increased microbial translocation and natural killer (NK) cell skewing towards an inflammatory state, with chromatin structure and phenotype typical of WNT transcription factor TCF7-dependent memory T cells. Cytokines that are elevated during acute HIV-1 infection reproduced the ILC and NK cell abnormalities ex vivo. These results show that inflammatory cytokines associated with HIV-1 infection irreversibly disrupt ILCs. This results in loss of gut epithelial integrity, microbial translocation and memory NK cells with heightened inflammatory potential, and explains the chronic inflammation in people with HIV-1.


Assuntos
Citocinas/sangue , HIV-1/imunologia , HIV-1/patogenicidade , Imunidade Inata , Células Matadoras Naturais/imunologia , Linfócitos/imunologia , Fator 1 de Transcrição de Linfócitos T/imunologia , Regulação da Expressão Gênica , Infecções por HIV/genética , Infecções por HIV/imunologia , Infecções por HIV/virologia , Homeostase/imunologia , Humanos , Memória Imunológica , Técnicas In Vitro , Inflamação/genética , Inflamação/imunologia , Inflamação/virologia , Fator 1 de Transcrição de Linfócitos T/genética , Via de Sinalização Wnt/imunologia
4.
Nat Immunol ; 21(3): 331-342, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32066950

RESUMO

Germinal center B cells (GCBCs) are critical for generating long-lived humoral immunity. How GCBCs meet the energetic challenge of rapid proliferation is poorly understood. Dividing lymphocytes typically rely on aerobic glycolysis over oxidative phosphorylation for energy. Here we report that GCBCs are exceptional among proliferating B and T cells, as they actively oxidize fatty acids (FAs) and conduct minimal glycolysis. In vitro, GCBCs had a very low glycolytic extracellular acidification rate but consumed oxygen in response to FAs. [13C6]-glucose feeding revealed that GCBCs generate significantly less phosphorylated glucose and little lactate. Further, GCBCs did not metabolize glucose into tricarboxylic acid (TCA) cycle intermediates. Conversely, [13C16]-palmitic acid labeling demonstrated that GCBCs generate most of their acetyl-CoA and acetylcarnitine from FAs. FA oxidation was functionally important, as drug-mediated and genetic dampening of FA oxidation resulted in a selective reduction of GCBCs. Hence, GCBCs appear to uncouple rapid proliferation from aerobic glycolysis.


Assuntos
Linfócitos B/metabolismo , Ácidos Graxos/metabolismo , Centro Germinativo/metabolismo , Animais , Linfócitos B/imunologia , Proliferação de Células , Metabolismo Energético , Ácidos Graxos não Esterificados/metabolismo , Expressão Gênica , Centro Germinativo/citologia , Centro Germinativo/imunologia , Glucose/metabolismo , Glicólise/genética , Técnicas In Vitro , Metaboloma , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Oxirredução , Fosforilação Oxidativa , Consumo de Oxigênio
5.
Cell ; 170(2): 284-297.e18, 2017 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-28689640

RESUMO

Major depressive disorder (MDD) patients display a common but often variable set of symptoms making successful, sustained treatment difficult to achieve. Separate depressive symptoms may be encoded by differential changes in distinct circuits in the brain, yet how discrete circuits underlie behavioral subsets of depression and how they adapt in response to stress has not been addressed. We identify two discrete circuits of parvalbumin-positive (PV) neurons in the ventral pallidum (VP) projecting to either the lateral habenula or ventral tegmental area contributing to depression. We find that these populations undergo different electrophysiological adaptations in response to social defeat stress, which are normalized by antidepressant treatment. Furthermore, manipulation of each population mediates either social withdrawal or behavioral despair, but not both. We propose that distinct components of the VP PV circuit can subserve related, yet separate depressive-like phenotypes in mice, which could ultimately provide a platform for symptom-specific treatments of depression.


Assuntos
Prosencéfalo Basal/fisiopatologia , Depressão/patologia , Neurônios/patologia , Animais , Aprendizagem da Esquiva , Prosencéfalo Basal/patologia , Depressão/fisiopatologia , Transtorno Depressivo Maior/patologia , Transtorno Depressivo Maior/fisiopatologia , Feminino , Técnicas In Vitro , Masculino , Mesencéfalo/metabolismo , Mesencéfalo/patologia , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/citologia , Parvalbuminas/metabolismo
6.
Cell ; 168(5): 775-788.e12, 2017 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-28235195

RESUMO

Stem-cell-based therapies can potentially reverse organ dysfunction and diseases, but the removal of impaired tissue and activation of a program leading to organ regeneration pose major challenges. In mice, a 4-day fasting mimicking diet (FMD) induces a stepwise expression of Sox17 and Pdx-1, followed by Ngn3-driven generation of insulin-producing ß cells, resembling that observed during pancreatic development. FMD cycles restore insulin secretion and glucose homeostasis in both type 2 and type 1 diabetes mouse models. In human type 1 diabetes pancreatic islets, fasting conditions reduce PKA and mTOR activity and induce Sox2 and Ngn3 expression and insulin production. The effects of the FMD are reversed by IGF-1 treatment and recapitulated by PKA and mTOR inhibition. These results indicate that a FMD promotes the reprogramming of pancreatic cells to restore insulin generation in islets from T1D patients and reverse both T1D and T2D phenotypes in mouse models. PAPERCLIP.


Assuntos
Diabetes Mellitus Tipo 1/dietoterapia , Diabetes Mellitus Tipo 2/dietoterapia , Jejum , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Dieta , Teste de Tolerância a Glucose , Humanos , Técnicas In Vitro , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas , Camundongos , Proteínas do Tecido Nervoso/genética , Pâncreas/citologia , Pâncreas/metabolismo , Transdução de Sinais , Transcriptoma
7.
Cell ; 164(4): 617-31, 2016 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-26871628

RESUMO

The motivation to seek social contact may arise from either positive or negative emotional states, as social interaction can be rewarding and social isolation can be aversive. While ventral tegmental area (VTA) dopamine (DA) neurons may mediate social reward, a cellular substrate for the negative affective state of loneliness has remained elusive. Here, we identify a functional role for DA neurons in the dorsal raphe nucleus (DRN), in which we observe synaptic changes following acute social isolation. DRN DA neurons show increased activity upon social contact following isolation, revealed by in vivo calcium imaging. Optogenetic activation of DRN DA neurons increases social preference but causes place avoidance. Furthermore, these neurons are necessary for promoting rebound sociability following an acute period of isolation. Finally, the degree to which these neurons modulate behavior is predicted by social rank, together supporting a role for DRN dopamine neurons in mediating a loneliness-like state. PAPERCLIP.


Assuntos
Neurônios Dopaminérgicos/patologia , Núcleo Dorsal da Rafe/patologia , Solidão , Animais , Dopamina/metabolismo , Núcleo Dorsal da Rafe/fisiopatologia , Ácido Glutâmico/metabolismo , Técnicas In Vitro , Masculino , Camundongos , Optogenética , Técnicas de Patch-Clamp , Recompensa , Sinapses , Área Tegmentar Ventral/fisiologia
8.
Cell ; 166(3): 651-663, 2016 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-27374333

RESUMO

Cellular bodies such as P bodies and PML nuclear bodies (PML NBs) appear to be phase-separated liquids organized by multivalent interactions among proteins and RNA molecules. Although many components of various cellular bodies are known, general principles that define body composition are lacking. We modeled cellular bodies using several engineered multivalent proteins and RNA. In vitro and in cells, these scaffold molecules form phase-separated liquids that concentrate low valency client proteins. Clients partition differently depending on the ratio of scaffolds, with a sharp switch across the phase diagram diagonal. Composition can switch rapidly through changes in scaffold concentration or valency. Natural PML NBs and P bodies show analogous partitioning behavior, suggesting how their compositions could be controlled by levels of PML SUMOylation or cellular mRNA concentration, respectively. The data suggest a conceptual framework for considering the composition and control thereof of cellular bodies assembled through heterotypic multivalent interactions.


Assuntos
Células Artificiais/química , Compartimento Celular , Organelas/química , Proteínas/química , Motivos de Aminoácidos , Composição Corporal , Proteínas de Transporte/química , Linhagem Celular , Núcleo Celular/química , Citoplasma , Eletroquímica , Células HeLa , Humanos , Técnicas In Vitro , Estrutura Molecular , Proteína de Ligação a Regiões Ricas em Polipirimidinas/química , Engenharia de Proteínas , Ubiquitinas/química , Leveduras
9.
Cell ; 162(2): 338-350, 2015 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-26186188

RESUMO

Spinal circuits can generate locomotor output in the absence of sensory or descending input, but the principles of locomotor circuit organization remain unclear. We sought insight into these principles by considering the elaboration of locomotor circuits across evolution. The identity of limb-innervating motor neurons was reverted to a state resembling that of motor neurons that direct undulatory swimming in primitive aquatic vertebrates, permitting assessment of the role of motor neuron identity in determining locomotor pattern. Two-photon imaging was coupled with spike inference to measure locomotor firing in hundreds of motor neurons in isolated mouse spinal cords. In wild-type preparations, we observed sequential recruitment of motor neurons innervating flexor muscles controlling progressively more distal joints. Strikingly, after reversion of motor neuron identity, virtually all firing patterns became distinctly flexor like. Our findings show that motor neuron identity directs locomotor circuit wiring and indicate the evolutionary primacy of flexor pattern generation.


Assuntos
Extremidades/fisiologia , Locomoção , Neurônios Motores/fisiologia , Músculo Esquelético/inervação , Animais , Evolução Biológica , Extremidades/inervação , Técnicas In Vitro , Camundongos , Medula Espinal/fisiologia
10.
Cell ; 162(6): 1404-17, 2015 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-26359991

RESUMO

Activation of orexigenic AgRP-expressing neurons in the arcuate nucleus of the hypothalamus potently promotes feeding, thus defining new regulators of AgRP neuron activity could uncover potential novel targets for obesity treatment. Here, we demonstrate that AgRP neurons express the purinergic receptor 6 (P2Y6), which is activated by uridine-diphosphate (UDP). In vivo, UDP induces ERK phosphorylation and cFos expression in AgRP neurons and promotes action potential firing of these neurons in brain slice recordings. Consequently, central application of UDP promotes feeding, and this response is abrogated upon pharmacologic or genetic inhibition of P2Y6 as well as upon pharmacogenetic inhibition of AgRP neuron activity. In obese animals, hypothalamic UDP content is elevated as a consequence of increased circulating uridine concentrations. Collectively, these experiments reveal a potential regulatory pathway in obesity, where peripheral uridine increases hypothalamic UDP concentrations, which in turn can promote feeding via PY6-dependent activation of AgRP neurons.


Assuntos
Regulação do Apetite , Hipotálamo/metabolismo , Obesidade/metabolismo , Receptores Purinérgicos P2/metabolismo , Difosfato de Uridina/metabolismo , Proteína Relacionada com Agouti/metabolismo , Animais , Modelos Animais de Doenças , Técnicas In Vitro , Masculino , Camundongos , Camundongos Endogâmicos C57BL
11.
Cell ; 162(3): 607-21, 2015 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-26232227

RESUMO

We identified a dominant missense mutation in the SCN transcription factor Zfhx3, termed short circuit (Zfhx3(Sci)), which accelerates circadian locomotor rhythms in mice. ZFHX3 regulates transcription via direct interaction with predicted AT motifs in target genes. The mutant protein has a decreased ability to activate consensus AT motifs in vitro. Using RNA sequencing, we found minimal effects on core clock genes in Zfhx3(Sci/+) SCN, whereas the expression of neuropeptides critical for SCN intercellular signaling was significantly disturbed. Moreover, mutant ZFHX3 had a decreased ability to activate AT motifs in the promoters of these neuropeptide genes. Lentiviral transduction of SCN slices showed that the ZFHX3-mediated activation of AT motifs is circadian, with decreased amplitude and robustness of these oscillations in Zfhx3(Sci/+) SCN slices. In conclusion, by cloning Zfhx3(Sci), we have uncovered a circadian transcriptional axis that determines the period and robustness of behavioral and SCN molecular rhythms.


Assuntos
Ritmo Circadiano , Regulação da Expressão Gênica , Proteínas de Homeodomínio/metabolismo , Neuropeptídeos/genética , Núcleo Supraquiasmático/metabolismo , Sequência de Aminoácidos , Animais , Regulação para Baixo , Proteínas de Homeodomínio/química , Proteínas de Homeodomínio/genética , Técnicas In Vitro , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Mutação , Motivos de Nucleotídeos , Regiões Promotoras Genéticas , Alinhamento de Sequência , Transcrição Gênica
12.
Cell ; 160(5): 870-881, 2015 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-25703095

RESUMO

Programmed ribosomal frameshifting produces alternative proteins from a single transcript. -1 frameshifting occurs on Escherichia coli's dnaX mRNA containing a slippery sequence AAAAAAG and peripheral mRNA structural barriers. Here, we reveal hidden aspects of the frameshifting process, including its exact location on the mRNA and its timing within the translation cycle. Mass spectrometry of translated products shows that ribosomes enter the -1 frame from not one specific codon but various codons along the slippery sequence and slip by not just -1 but also -4 or +2 nucleotides. Single-ribosome translation trajectories detect distinctive codon-scale fluctuations in ribosome-mRNA displacement across the slippery sequence, representing multiple ribosomal translocation attempts during frameshifting. Flanking mRNA structural barriers mechanically stimulate the ribosome to undergo back-and-forth translocation excursions, broadly exploring reading frames. Both experiments reveal aborted translation around mutant slippery sequences, indicating that subsequent fidelity checks on newly adopted codon position base pairings lead to either resumed translation or early termination.


Assuntos
Mutação da Fase de Leitura , Biossíntese de Proteínas , RNA Mensageiro/genética , Ribossomos/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Sequência de Bases , DNA Polimerase III/genética , Escherichia coli/metabolismo , Técnicas In Vitro , Espectrometria de Massas , Dados de Sequência Molecular
13.
Cell ; 161(3): 610-621, 2015 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-25910210

RESUMO

Cytotoxic brain edema triggered by neuronal swelling is the chief cause of mortality following brain trauma and cerebral infarct. Using fluorescence lifetime imaging to analyze contributions of intracellular ionic changes in brain slices, we find that intense Na(+) entry triggers a secondary increase in intracellular Cl(-) that is required for neuronal swelling and death. Pharmacological and siRNA-mediated knockdown screening identified the ion exchanger SLC26A11 unexpectedly acting as a voltage-gated Cl(-) channel that is activated upon neuronal depolarization to membrane potentials lower than -20 mV. Blockade of SLC26A11 activity attenuates both neuronal swelling and cell death. Therefore cytotoxic neuronal edema occurs when sufficient Na(+) influx and depolarization is followed by Cl(-) entry via SLC26A11. The resultant NaCl accumulation causes subsequent neuronal swelling leading to neuronal death. These findings shed light on unique elements of volume control in excitable cells and lay the ground for the development of specific treatments for brain edema.


Assuntos
Edema Encefálico/patologia , Antiportadores de Cloreto-Bicarbonato/metabolismo , Neurônios/metabolismo , Animais , Edema Encefálico/metabolismo , Morte Celular , Células Cultivadas , Antiportadores de Cloreto-Bicarbonato/química , Humanos , Técnicas In Vitro , Proteínas de Membrana Transportadoras/química , Proteínas de Membrana Transportadoras/metabolismo , Camundongos , Neurônios/patologia , Ratos , Sódio/metabolismo , Transportadores de Sulfato
14.
Nature ; 625(7994): 366-376, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38093015

RESUMO

Sexual reproduction of Toxoplasma gondii, confined to the felid gut, remains largely uncharted owing to ethical concerns regarding the use of cats as model organisms. Chromatin modifiers dictate the developmental fate of the parasite during its multistage life cycle, but their targeting to stage-specific cistromes is poorly described1,2. Here we found that the transcription factors AP2XII-1 and AP2XI-2 operate during the tachyzoite stage, a hallmark of acute toxoplasmosis, to silence genes necessary for merozoites, a developmental stage critical for subsequent sexual commitment and transmission to the next host, including humans. Their conditional and simultaneous depletion leads to a marked change in the transcriptional program, promoting a full transition from tachyzoites to merozoites. These in vitro-cultured pre-gametes have unique protein markers and undergo typical asexual endopolygenic division cycles. In tachyzoites, AP2XII-1 and AP2XI-2 bind DNA as heterodimers at merozoite promoters and recruit MORC and HDAC3 (ref. 1), thereby limiting chromatin accessibility and transcription. Consequently, the commitment to merogony stems from a profound epigenetic rewiring orchestrated by AP2XII-1 and AP2XI-2. Successful production of merozoites in vitro paves the way for future studies on Toxoplasma sexual development without the need for cat infections and holds promise for the development of therapies to prevent parasite transmission.


Assuntos
Gatos , Técnicas In Vitro , Estágios do Ciclo de Vida , Toxoplasma , Animais , Gatos/parasitologia , Humanos , Cromatina/genética , Cromatina/metabolismo , Modelos Animais de Doenças , Epigênese Genética , Técnicas In Vitro/métodos , Estágios do Ciclo de Vida/genética , Merozoítos/genética , Proteínas Nucleares/metabolismo , Regiões Promotoras Genéticas/genética , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Toxoplasma/genética , Toxoplasma/crescimento & desenvolvimento , Toxoplasma/fisiologia , Toxoplasmose/genética , Toxoplasmose/parasitologia , Toxoplasmose/transmissão , Transcrição Gênica
15.
Nature ; 630(8017): 596-608, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38898293

RESUMO

The evolution of the modern human brain was accompanied by distinct molecular and cellular specializations, which underpin our diverse cognitive abilities but also increase our susceptibility to neurological diseases. These features, some specific to humans and others shared with related species, manifest during different stages of brain development. In this multi-stage process, neural stem cells proliferate to produce a large and diverse progenitor pool, giving rise to excitatory or inhibitory neurons that integrate into circuits during further maturation. This process unfolds over varying time scales across species and has progressively become slower in the human lineage, with differences in tempo correlating with differences in brain size, cell number and diversity, and connectivity. Here we introduce the terms 'bradychrony' and 'tachycrony' to describe slowed and accelerated developmental tempos, respectively. We review how recent technical advances across disciplines, including advanced engineering of in vitro models, functional comparative genetics and high-throughput single-cell profiling, are leading to a deeper understanding of how specializations of the human brain arise during bradychronic neurodevelopment. Emerging insights point to a central role for genetics, gene-regulatory networks, cellular innovations and developmental tempo, which together contribute to the establishment of human specializations during various stages of neurodevelopment and at different points in evolution.


Assuntos
Evolução Biológica , Encéfalo , Animais , Humanos , Encéfalo/anatomia & histologia , Encéfalo/citologia , Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , Redes Reguladoras de Genes , Técnicas In Vitro , Células-Tronco Neurais/citologia , Células-Tronco Neurais/fisiologia , Neurogênese , Neurônios/citologia , Neurônios/fisiologia , Tamanho do Órgão , Análise de Célula Única , Fatores de Tempo , Inibição Neural
16.
Nature ; 629(8012): 704-709, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38693257

RESUMO

Choline is an essential nutrient that the human body needs in vast quantities for cell membrane synthesis, epigenetic modification and neurotransmission. The brain has a particularly high demand for choline, but how it enters the brain remains unknown1-3. The major facilitator superfamily transporter FLVCR1 (also known as MFSD7B or SLC49A1) was recently determined to be a choline transporter but is not highly expressed at the blood-brain barrier, whereas the related protein FLVCR2 (also known as MFSD7C or SLC49A2) is expressed in endothelial cells at the blood-brain barrier4-7. Previous studies have shown that mutations in human Flvcr2 cause cerebral vascular abnormalities, hydrocephalus and embryonic lethality, but the physiological role of FLVCR2 is unknown4,5. Here we demonstrate both in vivo and in vitro that FLVCR2 is a BBB choline transporter and is responsible for the majority of choline uptake into the brain. We also determine the structures of choline-bound FLVCR2 in both inward-facing and outward-facing states using cryo-electron microscopy. These results reveal how the brain obtains choline and provide molecular-level insights into how FLVCR2 binds choline in an aromatic cage and mediates its uptake. Our work could provide a novel framework for the targeted delivery of therapeutic agents into the brain.


Assuntos
Encéfalo , Colina , Proteínas de Membrana Transportadoras , Animais , Feminino , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Transporte Biológico , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Colina/metabolismo , Microscopia Crioeletrônica , Técnicas In Vitro , Proteínas de Membrana Transportadoras/química , Proteínas de Membrana Transportadoras/metabolismo , Proteínas de Membrana Transportadoras/ultraestrutura , Modelos Moleculares
17.
Nature ; 625(7996): 813-821, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38172637

RESUMO

Although the impact of host genetics on gut microbial diversity and the abundance of specific taxa is well established1-6, little is known about how host genetics regulates the genetic diversity of gut microorganisms. Here we conducted a meta-analysis of associations between human genetic variation and gut microbial structural variation in 9,015 individuals from four Dutch cohorts. Strikingly, the presence rate of a structural variation segment in Faecalibacterium prausnitzii that harbours an N-acetylgalactosamine (GalNAc) utilization gene cluster is higher in individuals who secrete the type A oligosaccharide antigen terminating in GalNAc, a feature that is jointly determined by human ABO and FUT2 genotypes, and we could replicate this association in a Tanzanian cohort. In vitro experiments demonstrated that GalNAc can be used as the sole carbohydrate source for F. prausnitzii strains that carry the GalNAc-metabolizing pathway. Further in silico and in vitro studies demonstrated that other ABO-associated species can also utilize GalNAc, particularly Collinsella aerofaciens. The GalNAc utilization genes are also associated with the host's cardiometabolic health, particularly in individuals with mucosal A-antigen. Together, the findings of our study demonstrate that genetic associations across the human genome and bacterial metagenome can provide functional insights into the reciprocal host-microbiome relationship.


Assuntos
Bactérias , Microbioma Gastrointestinal , Interações entre Hospedeiro e Microrganismos , Metagenoma , Humanos , Acetilgalactosamina/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Estudos de Coortes , Simulação por Computador , Faecalibacterium prausnitzii/genética , Microbioma Gastrointestinal/genética , Genoma Humano/genética , Genótipo , Interações entre Hospedeiro e Microrganismos/genética , Técnicas In Vitro , Metagenoma/genética , Família Multigênica , Países Baixos , Tanzânia
18.
Nature ; 631(8019): 170-178, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38768632

RESUMO

Epigenetic reprogramming resets parental epigenetic memories and differentiates primordial germ cells (PGCs) into mitotic pro-spermatogonia or oogonia. This process ensures sexually dimorphic germ cell development for totipotency1. In vitro reconstitution of epigenetic reprogramming in humans remains a fundamental challenge. Here we establish a strategy for inducing epigenetic reprogramming and differentiation of pluripotent stem-cell-derived human PGC-like cells (hPGCLCs) into mitotic pro-spermatogonia or oogonia, coupled with their extensive amplification (about >1010-fold). Bone morphogenetic protein (BMP) signalling is a key driver of these processes. BMP-driven hPGCLC differentiation involves attenuation of the MAPK (ERK) pathway and both de novo and maintenance DNA methyltransferase activities, which probably promote replication-coupled, passive DNA demethylation. hPGCLCs deficient in TET1, an active DNA demethylase abundant in human germ cells2,3, differentiate into extraembryonic cells, including amnion, with de-repression of key genes that bear bivalent promoters. These cells fail to fully activate genes vital for spermatogenesis and oogenesis, and their promoters remain methylated. Our study provides a framework for epigenetic reprogramming in humans and an important advance in human biology. Through the generation of abundant mitotic pro-spermatogonia and oogonia-like cells, our results also represent a milestone for human in vitro gametogenesis research and its potential translation into reproductive medicine.


Assuntos
Reprogramação Celular , Epigênese Genética , Células Germinativas , Técnicas In Vitro , Feminino , Humanos , Masculino , Âmnio/citologia , Proteínas Morfogenéticas Ósseas/metabolismo , Reprogramação Celular/genética , Metilação de DNA/genética , Células Germinativas/metabolismo , Células Germinativas/citologia , Sistema de Sinalização das MAP Quinases , Mitose/genética , Oxigenases de Função Mista/deficiência , Oogênese/genética , Oogônios/citologia , Oogônios/metabolismo , Células-Tronco Pluripotentes/citologia , Células-Tronco Pluripotentes/metabolismo , Regiões Promotoras Genéticas/genética , Espermatogênese/genética , Espermatogônias/citologia , Espermatogônias/metabolismo , Regulação da Expressão Gênica no Desenvolvimento
19.
Nature ; 626(8000): 836-842, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38267582

RESUMO

HIV can infect non-dividing cells because the viral capsid can overcome the selective barrier of the nuclear pore complex and deliver the genome directly into the nucleus1,2. Remarkably, the intact HIV capsid is more than 1,000 times larger than the size limit prescribed by the diffusion barrier of the nuclear pore3. This barrier in the central channel of the nuclear pore is composed of intrinsically disordered nucleoporin domains enriched in phenylalanine-glycine (FG) dipeptides. Through multivalent FG interactions, cellular karyopherins and their bound cargoes solubilize in this phase to drive nucleocytoplasmic transport4. By performing an in vitro dissection of the nuclear pore complex, we show that a pocket on the surface of the HIV capsid similarly interacts with FG motifs from multiple nucleoporins and that this interaction licences capsids to penetrate FG-nucleoporin condensates. This karyopherin mimicry model addresses a key conceptual challenge for the role of the HIV capsid in nuclear entry and offers an explanation as to how an exogenous entity much larger than any known cellular cargo may be able to non-destructively breach the nuclear envelope.


Assuntos
Proteínas do Capsídeo , Glicina , HIV , Carioferinas , Mimetismo Molecular , Complexo de Proteínas Formadoras de Poros Nucleares , Poro Nuclear , Fenilalanina , Humanos , Transporte Ativo do Núcleo Celular , Proteínas do Capsídeo/química , Proteínas do Capsídeo/metabolismo , Difusão , Dipeptídeos/química , Dipeptídeos/metabolismo , Glicina/metabolismo , HIV/química , HIV/metabolismo , Técnicas In Vitro , Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/metabolismo , Carioferinas/metabolismo , Poro Nuclear/química , Poro Nuclear/metabolismo , Poro Nuclear/virologia , Complexo de Proteínas Formadoras de Poros Nucleares/química , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Permeabilidade , Fenilalanina/metabolismo , Solubilidade , Internalização do Vírus , Capsídeo/química , Capsídeo/metabolismo
20.
Nature ; 632(8023): 174-181, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38987594

RESUMO

Changes in the gut microbiome have pivotal roles in the pathogenesis of acute graft-versus-host disease (aGVHD) after allogenic haematopoietic cell transplantation (allo-HCT)1-6. However, effective methods for safely resolving gut dysbiosis have not yet been established. An expansion of the pathogen Enterococcus faecalis in the intestine, associated with dysbiosis, has been shown to be a risk factor for aGVHD7-10. Here we analyse the intestinal microbiome of patients with allo-HCT, and find that E. faecalis escapes elimination and proliferates in the intestine by forming biofilms, rather than by acquiring drug-resistance genes. We isolated cytolysin-positive highly pathogenic E. faecalis from faecal samples and identified an anti-E. faecalis enzyme derived from E. faecalis-specific bacteriophages by analysing bacterial whole-genome sequencing data. The antibacterial enzyme had lytic activity against the biofilm of E. faecalis in vitro and in vivo. Furthermore, in aGVHD-induced gnotobiotic mice that were colonized with E. faecalis or with patient faecal samples characterized by the domination of Enterococcus, levels of intestinal cytolysin-positive E. faecalis were decreased and survival was significantly increased in the group that was treated with the E. faecalis-specific enzyme, compared with controls. Thus, administration of a phage-derived antibacterial enzyme that is specific to biofilm-forming pathogenic E. faecalis-which is difficult to eliminate with existing antibiotics-might provide an approach to protect against aGVHD.


Assuntos
Bacteriófagos , Enterococcus faecalis , Microbioma Gastrointestinal , Doença Enxerto-Hospedeiro , Adulto , Idoso , Animais , Feminino , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Adulto Jovem , Bacteriófagos/enzimologia , Bacteriófagos/genética , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Disbiose/complicações , Disbiose/microbiologia , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecalis/genética , Enterococcus faecalis/crescimento & desenvolvimento , Enterococcus faecalis/metabolismo , Enterococcus faecalis/virologia , Fezes/microbiologia , Vida Livre de Germes , Doença Enxerto-Hospedeiro/complicações , Doença Enxerto-Hospedeiro/microbiologia , Doença Enxerto-Hospedeiro/prevenção & controle , Doença Enxerto-Hospedeiro/terapia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Técnicas In Vitro , Intestinos/efeitos dos fármacos , Intestinos/microbiologia , Perforina/metabolismo , Fatores de Risco , Transplante Homólogo/efeitos adversos , Sequenciamento Completo do Genoma , Farmacorresistência Bacteriana/efeitos dos fármacos , Antibacterianos/farmacologia
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa