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1.
Cell ; 160(6): 1099-110, 2015 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-25768906

RESUMEN

Hepatitis C virus (HCV) uniquely requires the liver-specific microRNA-122 for replication, yet global effects on endogenous miRNA targets during infection are unexplored. Here, high-throughput sequencing and crosslinking immunoprecipitation (HITS-CLIP) experiments of human Argonaute (AGO) during HCV infection showed robust AGO binding on the HCV 5'UTR at known and predicted miR-122 sites. On the human transcriptome, we observed reduced AGO binding and functional mRNA de-repression of miR-122 targets during virus infection. This miR-122 "sponge" effect was relieved and redirected to miR-15 targets by swapping the miRNA tropism of the virus. Single-cell expression data from reporters containing miR-122 sites showed significant de-repression during HCV infection depending on expression level and site number. We describe a quantitative mathematical model of HCV-induced miR-122 sequestration and propose that such miR-122 inhibition by HCV RNA may result in global de-repression of host miR-122 targets, providing an environment fertile for the long-term oncogenic potential of HCV.


Asunto(s)
Hepacivirus/metabolismo , Hepatitis C/metabolismo , Hepatitis C/virología , MicroARNs/metabolismo , ARN Viral/metabolismo , Proteínas Argonautas/metabolismo , Secuencia de Bases , Línea Celular Tumoral , Factores Eucarióticos de Iniciación/metabolismo , Hepacivirus/genética , Humanos , Hígado/metabolismo , Hígado/virología , Datos de Secuencia Molecular , ARN Viral/química , Replicación Viral
2.
Cell ; 146(2): 247-61, 2011 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-21784246

RESUMEN

FMRP loss of function causes Fragile X syndrome (FXS) and autistic features. FMRP is a polyribosome-associated neuronal RNA-binding protein, suggesting that it plays a key role in regulating neuronal translation, but there has been little consensus regarding either its RNA targets or mechanism of action. Here, we use high-throughput sequencing of RNAs isolated by crosslinking immunoprecipitation (HITS-CLIP) to identify FMRP interactions with mouse brain polyribosomal mRNAs. FMRP interacts with the coding region of transcripts encoding pre- and postsynaptic proteins and transcripts implicated in autism spectrum disorders (ASD). We developed a brain polyribosome-programmed translation system, revealing that FMRP reversibly stalls ribosomes specifically on its target mRNAs. Our results suggest that loss of a translational brake on the synthesis of a subset of synaptic proteins contributes to FXS. In addition, they provide insight into the molecular basis of the cognitive and allied defects in FXS and ASD and suggest multiple targets for clinical intervention.


Asunto(s)
Trastorno Autístico/metabolismo , Encéfalo/metabolismo , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/metabolismo , Síndrome del Cromosoma X Frágil/metabolismo , Ribosomas/metabolismo , Sinapsis/metabolismo , Animales , Trastorno Autístico/fisiopatología , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/genética , Síndrome del Cromosoma X Frágil/fisiopatología , Humanos , Ratones , Ratones Noqueados , Polirribosomas/metabolismo , Biosíntesis de Proteínas , Proteínas de Unión al ARN , Análisis de Secuencia de ARN
3.
Genes Dev ; 31(10): 990-1006, 2017 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-28637692

RESUMEN

Understanding the biologic role of N6-methyladenosine (m6A) RNA modifications in mRNA requires an understanding of when and where in the life of a pre-mRNA transcript the modifications are made. We found that HeLa cell chromatin-associated nascent pre-mRNA (CA-RNA) contains many unspliced introns and m6A in exons but very rarely in introns. The m6A methylation is essentially completed upon the release of mRNA into the nucleoplasm. Furthermore, the content and location of each m6A modification in steady-state cytoplasmic mRNA are largely indistinguishable from those in the newly synthesized CA-RNA or nucleoplasmic mRNA. This result suggests that quantitatively little methylation or demethylation occurs in cytoplasmic mRNA. In addition, only ∼10% of m6As in CA-RNA are within 50 nucleotides of 5' or 3' splice sites, and the vast majority of exons harboring m6A in wild-type mouse stem cells is spliced the same in cells lacking the major m6A methyltransferase Mettl3. Both HeLa and mouse embryonic stem cell mRNAs harboring m6As have shorter half-lives, and thousands of these mRNAs have increased half-lives (twofold or more) in Mettl3 knockout cells compared with wild type. In summary, m6A is added to exons before or soon after exon definition in nascent pre-mRNA, and while m6A is not required for most splicing, its addition in the nascent transcript is a determinant of cytoplasmic mRNA stability.


Asunto(s)
Citoplasma/metabolismo , Precursores del ARN/metabolismo , Empalme del ARN , ARN Mensajero/metabolismo , Animales , Cromatina/metabolismo , Células Madre Embrionarias , Exones/genética , Técnicas de Inactivación de Genes , Células HeLa , Humanos , Intrones/genética , Metilación , Metiltransferasas/genética , Metiltransferasas/metabolismo , Ratones
4.
N Engl J Med ; 383(3): 218-228, 2020 07 16.
Artículo en Inglés | MEDLINE | ID: mdl-32668112

RESUMEN

BACKGROUND: Rheumatoid arthritis, like many inflammatory diseases, is characterized by episodes of quiescence and exacerbation (flares). The molecular events leading to flares are unknown. METHODS: We established a clinical and technical protocol for repeated home collection of blood in patients with rheumatoid arthritis to allow for longitudinal RNA sequencing (RNA-seq). Specimens were obtained from 364 time points during eight flares over a period of 4 years in our index patient, as well as from 235 time points during flares in three additional patients. We identified transcripts that were differentially expressed before flares and compared these with data from synovial single-cell RNA-seq. Flow cytometry and sorted-blood-cell RNA-seq in additional patients were used to validate the findings. RESULTS: Consistent changes were observed in blood transcriptional profiles 1 to 2 weeks before a rheumatoid arthritis flare. B-cell activation was followed by expansion of circulating CD45-CD31-PDPN+ preinflammatory mesenchymal, or PRIME, cells in the blood from patients with rheumatoid arthritis; these cells shared features of inflammatory synovial fibroblasts. Levels of circulating PRIME cells decreased during flares in all 4 patients, and flow cytometry and sorted-cell RNA-seq confirmed the presence of PRIME cells in 19 additional patients with rheumatoid arthritis. CONCLUSIONS: Longitudinal genomic analysis of rheumatoid arthritis flares revealed PRIME cells in the blood during the period before a flare and suggested a model in which these cells become activated by B cells in the weeks before a flare and subsequently migrate out of the blood into the synovium. (Funded by the National Institutes of Health and others.).


Asunto(s)
Artritis Reumatoide/sangre , Linfocitos B/fisiología , Expresión Génica , Células Madre Mesenquimatosas , Análisis de Secuencia de ARN/métodos , Adulto , Artritis Reumatoide/genética , Artritis Reumatoide/inmunología , Femenino , Fibroblastos/metabolismo , Citometría de Flujo , Humanos , Masculino , Células Madre Mesenquimatosas/metabolismo , Persona de Mediana Edad , Gravedad del Paciente , Encuestas y Cuestionarios , Brote de los Síntomas , Líquido Sinovial/citología
5.
Genes Dev ; 29(19): 2037-53, 2015 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-26404942

RESUMEN

We adapted UV CLIP (cross-linking immunoprecipitation) to accurately locate tens of thousands of m(6)A residues in mammalian mRNA with single-nucleotide resolution. More than 70% of these residues are present in the 3'-most (last) exons, with a very sharp rise (sixfold) within 150-400 nucleotides of the start of the last exon. Two-thirds of last exon m(6)A and >40% of all m(6)A in mRNA are present in 3' untranslated regions (UTRs); contrary to earlier suggestions, there is no preference for location of m(6)A sites around stop codons. Moreover, m(6)A is significantly higher in noncoding last exons than in next-to-last exons harboring stop codons. We found that m(6)A density peaks early in the 3' UTR and that, among transcripts with alternative polyA (APA) usage in both the brain and the liver, brain transcripts preferentially use distal polyA sites, as reported, and also show higher proximal m(6)A density in the last exons. Furthermore, when we reduced m6A methylation by knocking down components of the methylase complex and then examined 661 transcripts with proximal m6A peaks in last exons, we identified a set of 111 transcripts with altered (approximately two-thirds increased proximal) APA use. Taken together, these observations suggest a role of m(6)A modification in regulating proximal alternative polyA choice.


Asunto(s)
Regiones no Traducidas 3'/genética , Adenosina/metabolismo , Metilación de ADN/genética , Exones/genética , Regulación de la Expresión Génica , ARN Mensajero/química , Animales , Encéfalo/citología , Encéfalo/metabolismo , Línea Celular , Técnicas de Silenciamiento del Gen , Humanos , Hígado/citología , Hígado/metabolismo , Ratones , Poliadenilación , ARNt Metiltransferasas/genética , ARNt Metiltransferasas/metabolismo
6.
Genes Dev ; 26(14): 1626-42, 2012 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-22802532

RESUMEN

Two polypyrimidine tract RNA-binding proteins (PTBs), one near-ubiquitously expressed (Ptbp1) and another highly tissue-restricted (Ptbp2), regulate RNA in interrelated but incompletely understood ways. Ptbp1, a splicing regulator, is replaced in the brain and differentiated neuronal cell lines by Ptbp2. To define the roles of Ptbp2 in the nervous system, we generated two independent Ptbp2-null strains, unexpectedly revealing that Ptbp2 is expressed in neuronal progenitors and is essential for postnatal survival. A HITS-CLIP (high-throughput sequencing cross-linking immunoprecipitation)-generated map of reproducible Ptbp2-RNA interactions in the developing mouse neocortex, combined with results from splicing-sensitive microarrays, demonstrated that the major action of Ptbp2 is to inhibit adult-specific alternative exons by binding pyrimidine-rich sequences upstream of and/or within them. These regulated exons are present in mRNAs encoding proteins associated with control of cell fate, proliferation, and the actin cytoskeleton, suggesting a role for Ptbp2 in neurogenesis. Indeed, neuronal progenitors in the Ptbp2-null brain exhibited an aberrant polarity and were associated with regions of premature neurogenesis and reduced progenitor pools. Thus, Ptbp2 inhibition of a discrete set of adult neuronal exons underlies early brain development prior to neuronal differentiation and is essential for postnatal survival.


Asunto(s)
Empalme Alternativo/fisiología , Encéfalo/embriología , Diferenciación Celular/fisiología , Proteínas del Tejido Nervioso/metabolismo , Células-Madre Neurales/metabolismo , Proteína de Unión al Tracto de Polipirimidina/metabolismo , ARN Mensajero/metabolismo , Animales , Encéfalo/metabolismo , Exones/fisiología , Ribonucleoproteínas Nucleares Heterogéneas/genética , Ribonucleoproteínas Nucleares Heterogéneas/metabolismo , Ratones , Ratones Mutantes , Proteínas del Tejido Nervioso/genética , Células-Madre Neurales/citología , Proteína de Unión al Tracto de Polipirimidina/genética , ARN Mensajero/genética
7.
Eur J Immunol ; 44(11): 3240-51, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25103845

RESUMEN

Paraneoplastic neurologic diseases (PND) involving immune responses directed toward intracellular antigens are poorly understood. Here, we examine immunity to the PND antigen Nova2, which is expressed exclusively in central nervous system (CNS) neurons. We hypothesized that ectopic expression of neuronal antigen in the periphery could incite PND. In our C57BL/6 mouse model, CNS antigen expression limits antigen-specific CD4+ and CD8+ T-cell expansion. Chimera experiments demonstrate that this tolerance is mediated by antigen expression in nonhematopoietic cells. CNS antigen expression does not limit tumor rejection by adoptively transferred transgenic T cells but does limit the generation of a memory population that can be expanded upon secondary challenge in vivo. Despite mediating cancer rejection, adoptively transferred transgenic T cells do not lead to paraneoplastic neuronal targeting. Preliminary experiments suggest an additional requirement for humoral activation to induce CNS autoimmunity. This work provides evidence that the requirements for cancer immunity and neuronal autoimmunity are uncoupled. Since humoral immunity was not required for tumor rejection, B-cell targeting therapy, such as rituximab, may be a rational treatment option for PND that does not hamper tumor immunity.


Asunto(s)
Autoinmunidad , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Sistema Nervioso Central/inmunología , Síndromes Paraneoplásicos del Sistema Nervioso/inmunología , Traslado Adoptivo , Animales , Anticuerpos Monoclonales de Origen Murino/farmacología , Antígenos de Neoplasias/inmunología , Antineoplásicos/farmacología , Linfocitos B/inmunología , Sistema Nervioso Central/citología , Tolerancia Inmunológica , Inmunización , Factores Inmunológicos/farmacología , Memoria Inmunológica , Activación de Linfocitos/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Antígeno Ventral Neuro-Oncológico , Neuronas/inmunología , Proteínas de Unión al ARN/inmunología , Rituximab , beta-Galactosidasa/genética , beta-Galactosidasa/inmunología
8.
Nature ; 456(7221): 464-9, 2008 Nov 27.
Artículo en Inglés | MEDLINE | ID: mdl-18978773

RESUMEN

Protein-RNA interactions have critical roles in all aspects of gene expression. However, applying biochemical methods to understand such interactions in living tissues has been challenging. Here we develop a genome-wide means of mapping protein-RNA binding sites in vivo, by high-throughput sequencing of RNA isolated by crosslinking immunoprecipitation (HITS-CLIP). HITS-CLIP analysis of the neuron-specific splicing factor Nova revealed extremely reproducible RNA-binding maps in multiple mouse brains. These maps provide genome-wide in vivo biochemical footprints confirming the previous prediction that the position of Nova binding determines the outcome of alternative splicing; moreover, they are sufficiently powerful to predict Nova action de novo. HITS-CLIP revealed a large number of Nova-RNA interactions in 3' untranslated regions, leading to the discovery that Nova regulates alternative polyadenylation in the brain. HITS-CLIP, therefore, provides a robust, unbiased means to identify functional protein-RNA interactions in vivo.


Asunto(s)
Empalme Alternativo/genética , Antígenos de Neoplasias/metabolismo , Genoma/genética , Neocórtex/citología , Neuronas/metabolismo , ARN Mensajero/metabolismo , Proteínas de Unión al ARN/metabolismo , Animales , Antígenos de Neoplasias/genética , Línea Celular , Reactivos de Enlaces Cruzados/química , Reactivos de Enlaces Cruzados/metabolismo , Exones/genética , Genómica , Humanos , Inmunoprecipitación , Ratones , Antígeno Ventral Neuro-Oncológico , Especificidad de Órganos , Poliadenilación/genética , ARN Mensajero/genética , Proteínas de Unión al ARN/genética
9.
Nat Neurosci ; 27(5): 822-835, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38589584

RESUMEN

Learning and memory require activity-induced changes in dendritic translation, but which mRNAs are involved and how they are regulated are unclear. In this study, to monitor how depolarization impacts local dendritic biology, we employed a dendritically targeted proximity labeling approach followed by crosslinking immunoprecipitation, ribosome profiling and mass spectrometry. Depolarization of primary cortical neurons with KCl or the glutamate agonist DHPG caused rapid reprogramming of dendritic protein expression, where changes in dendritic mRNAs and proteins are weakly correlated. For a subset of pre-localized messages, depolarization increased the translation of upstream open reading frames (uORFs) and their downstream coding sequences, enabling localized production of proteins involved in long-term potentiation, cell signaling and energy metabolism. This activity-dependent translation was accompanied by the phosphorylation and recruitment of the non-canonical translation initiation factor eIF4G2, and the translated uORFs were sufficient to confer depolarization-induced, eIF4G2-dependent translational control. These studies uncovered an unanticipated mechanism by which activity-dependent uORF translational control by eIF4G2 couples activity to local dendritic remodeling.


Asunto(s)
Dendritas , Factor 4G Eucariótico de Iniciación , Sistemas de Lectura Abierta , Biosíntesis de Proteínas , Animales , Ratones , Células Cultivadas , Dendritas/metabolismo , Factor 4G Eucariótico de Iniciación/metabolismo , Neuronas/metabolismo , Sistemas de Lectura Abierta/genética , Cloruro de Potasio/farmacología , Biosíntesis de Proteínas/fisiología
10.
bioRxiv ; 2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-36993710

RESUMEN

Attention is required for most higher-order cognitive functions. Prior studies have revealed functional roles for the prefrontal cortex and its extended circuits to enabling attention, but the underlying molecular processes and their impacts on cellular and circuit function remain poorly understood. To develop insights, we here took an unbiased forward genetics approach to identify single genes of large effect on attention. We studied 200 genetically diverse mice on measures of pre-attentive processing and through genetic mapping identified a small locus on chromosome 13 (95%CI: 92.22-94.09 Mb) driving substantial variation (19%) in this trait. Further characterization of the locus revealed a causative gene, Homer1, encoding a synaptic protein, where down-regulation of its short isoforms in prefrontal cortex (PFC) during early postnatal development led to improvements in multiple measures of attention in the adult. Subsequent mechanistic studies revealed that prefrontal Homer1 down-regulation is associated with GABAergic receptor up-regulation in those same cells. This enhanced inhibitory influence, together with dynamic neuromodulatory coupling, led to strikingly low PFC activity at baseline periods of the task but targeted elevations at cue onset, predicting short-latency correct choices. Notably high-Homer1, low-attentional performers, exhibited uniformly elevated PFC activity throughout the task. We thus identify a single gene of large effect on attention - Homer1 - and find that it improves prefrontal inhibitory tone and signal-to-noise (SNR) to enhance attentional performance. A therapeutic strategy focused on reducing prefrontal activity and increasing SNR, rather than uniformly elevating PFC activity, may complement the use of stimulants to improve attention.

11.
Nat Commun ; 14(1): 3956, 2023 07 05.
Artículo en Inglés | MEDLINE | ID: mdl-37407548

RESUMEN

The ability to use blood to predict the outcomes of Parkinson's disease, including disease progression and cognitive and motor complications, would be of significant clinical value. We undertook bulk RNA sequencing from the caudate and putamen of postmortem Parkinson's disease (n = 35) and control (n = 40) striatum, and compared molecular profiles with clinical features and bulk RNA sequencing data obtained from antemortem peripheral blood. Cognitive and motor complications of Parkinson's disease were associated with molecular changes in the caudate (stress response) and putamen (endothelial pathways) respectively. Later and earlier-onset Parkinson's disease were molecularly distinct, and disease duration was associated with changes in caudate (oligodendrocyte development) and putamen (cellular senescence), respectively. Transcriptome patterns in the postmortem Parkinson's disease brain were also evident in antemortem peripheral blood, and correlated with clinical features of the disease. Together, these findings identify molecular signatures in Parkinson's disease patients' brain and blood of potential pathophysiologic and prognostic importance.


Asunto(s)
Enfermedad de Parkinson , Humanos , Enfermedad de Parkinson/metabolismo , Transcriptoma , Encéfalo/metabolismo , Cuerpo Estriado/metabolismo , Putamen
12.
Sci Transl Med ; 15(684): eabq8476, 2023 02 22.
Artículo en Inglés | MEDLINE | ID: mdl-36812347

RESUMEN

Periodontal disease is more common in individuals with rheumatoid arthritis (RA) who have detectable anti-citrullinated protein antibodies (ACPAs), implicating oral mucosal inflammation in RA pathogenesis. Here, we performed paired analysis of human and bacterial transcriptomics in longitudinal blood samples from RA patients. We found that patients with RA and periodontal disease experienced repeated oral bacteremias associated with transcriptional signatures of ISG15+HLADRhi and CD48highS100A2pos monocytes, recently identified in inflamed RA synovia and blood of those with RA flares. The oral bacteria observed transiently in blood were broadly citrullinated in the mouth, and their in situ citrullinated epitopes were targeted by extensively somatically hypermutated ACPAs encoded by RA blood plasmablasts. Together, these results suggest that (i) periodontal disease results in repeated breaches of the oral mucosa that release citrullinated oral bacteria into circulation, which (ii) activate inflammatory monocyte subsets that are observed in inflamed RA synovia and blood of RA patients with flares and (iii) activate ACPA B cells, thereby promoting affinity maturation and epitope spreading to citrullinated human antigens.


Asunto(s)
Artritis Reumatoide , Enfermedades Periodontales , Humanos , Autoanticuerpos , Mucosa Bucal , Formación de Anticuerpos , Epítopos , Bacterias
13.
Proc Natl Acad Sci U S A ; 106(9): 3513-8, 2009 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-19221030

RESUMEN

Synapse formation at the neuromuscular junction (NMJ) requires an alternatively spliced variant of agrin (Z(+) agrin) that is produced only by neurons. Here, we show that Nova1 and Nova2, neuron-specific splicing factors identified as targets in autoimmune motor disease, are essential regulators of Z(+) agrin. Nova1/Nova2 double knockout mice are paralyzed and fail to cluster AChRs at the NMJ, and breeding them with transgenic mice constitutively expressing Z(+) agrin in motor neurons rescued AChR clustering. Surprisingly, however, these rescued mice remained paralyzed, while electrophysiologic studies demonstrated that the motor axon and synapse were functional-spontaneous and evoked recordings revealed synaptic transmission and muscle contraction. These results point to a proximal defect in motor neuron firing in the absence of Nova and reveal a previously unsuspected role for RNA regulation in the physiologic activation of motor neurons.


Asunto(s)
Agrina/metabolismo , Empalme Alternativo/genética , Antígenos de Neoplasias/metabolismo , Enfermedad de la Neurona Motora/metabolismo , Enfermedad de la Neurona Motora/fisiopatología , Proteínas del Tejido Nervioso/deficiencia , Proteínas del Tejido Nervioso/metabolismo , Proteínas de Unión al ARN/metabolismo , Sinapsis/metabolismo , Agrina/química , Agrina/genética , Secuencia de Aminoácidos , Animales , Antígenos de Neoplasias/genética , Electrofisiología , Embrión de Mamíferos/embriología , Embrión de Mamíferos/metabolismo , Regulación de la Expresión Génica , Ratones , Ratones Noqueados , Datos de Secuencia Molecular , Enfermedad de la Neurona Motora/genética , Proteínas del Tejido Nervioso/genética , Antígeno Ventral Neuro-Oncológico , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas de Unión al ARN/genética
14.
J Clin Invest ; 132(18)2022 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-36106631

RESUMEN

In addition to playing a major role in tumor cell biology, p53 generates a microenvironment that promotes antitumor immune surveillance via tumor-associated macrophages. We examined whether increasing p53 signaling in the tumor microenvironment influences antitumor T cell immunity. Our findings indicate that increased p53 signaling induced either pharmacologically with APR-246 (eprenetapopt) or in p53-overexpressing transgenic mice can disinhibit antitumor T cell immunity and augment the efficacy of immune checkpoint blockade. We demonstrated that increased p53 expression in tumor-associated macrophages induces canonical p53-associated functions such as senescence and activation of a p53-dependent senescence-associated secretory phenotype. This was linked with decreased expression of proteins associated with M2 polarization by tumor-associated macrophages. Our preclinical data led to the development of a clinical trial in patients with solid tumors combining APR-246 with pembrolizumab. Biospecimens from select patients participating in this ongoing trial showed that there was a suppression of M2-polarized myeloid cells and increase in T cell proliferation with therapy in those who responded to the therapy. Our findings, based on both genetic and a small molecule-based pharmacological approach, suggest that increasing p53 expression in tumor-associated macrophages reprograms the tumor microenvironment to augment the response to immune checkpoint blockade.


Asunto(s)
Inhibidores de Puntos de Control Inmunológico , Macrófagos Asociados a Tumores , Animales , Inhibidores de Puntos de Control Inmunológico/farmacología , Ratones , Quinuclidinas , Microambiente Tumoral , Proteína p53 Supresora de Tumor/genética
15.
Elife ; 102021 12 23.
Artículo en Inglés | MEDLINE | ID: mdl-34939924

RESUMEN

Neurons rely on translation of synaptic mRNAs in order to generate activity-dependent changes in plasticity. Here, we develop a strategy combining compartment-specific crosslinking immunoprecipitation (CLIP) and translating ribosome affinity purification (TRAP) in conditionally tagged mice to precisely define the ribosome-bound dendritic transcriptome of CA1 pyramidal neurons. We identify CA1 dendritic transcripts with differentially localized mRNA isoforms generated by alternative polyadenylation and alternative splicing, including many that have altered protein-coding capacity. Among dendritic mRNAs, FMRP targets were found to be overrepresented. Cell-type-specific FMRP-CLIP and TRAP in microdissected CA1 neuropil revealed 383 dendritic FMRP targets and suggests that FMRP differentially regulates functionally distinct modules in CA1 dendrites and cell bodies. FMRP regulates ~15-20% of mRNAs encoding synaptic functions and 10% of chromatin modulators, in the dendrite and cell body, respectively. In the absence of FMRP, dendritic FMRP targets had increased ribosome association, consistent with a function for FMRP in synaptic translational repression. Conversely, downregulation of FMRP targets involved in chromatin regulation in cell bodies suggests a role for FMRP in stabilizing mRNAs containing stalled ribosomes in this compartment. Together, the data support a model in which FMRP regulates the translation and expression of synaptic and nuclear proteins within different compartments of a single neuronal cell type.


The brain has over 100 billion neurons that together form vast networks to relay electrical signals. A neuron receives electrical signals from other neurons via branch-like structures known as dendrites. The signals then travel into the cell body of the neuron. If their sum reaches a threshold, they fire a new signal through a single outgoing projection known as the axon, which is connected to the dendrites of other neurons. A single neuron has thousands of dendrites that each receive inputs from different axons, and it is thought that the strengthening and weakening of these dendritic connections enables us to learn and store memories. Dendrites are filled with molecules known as messenger ribonucleic acids (mRNAs) that act as templates to make proteins. Axonal signals reaching the dendrites can trigger these mRNAs to make new proteins that strengthen or weaken the connections between the two neurons, which is believed to be necessary for generating long-term memories. A protein called FMRP is found in both the cell body and dendrites and is able to bind to and regulate the ability of mRNAs to make proteins. A loss of the gene encoding FMRP is the most common cause of inherited intellectual disability and autism in humans, but it remains unclear precisely what role this protein plays in learning and memory. Hale et al. used genetic and bioinformatics approaches to specifically study mRNAs in the dendrites and the cell body of a specific type of neuron involved in memory in mice. The experiments revealed that FMRP played different roles in the dendrites and cell body. In the dendrites, FMRP interacted with mRNAs encoding proteins that can change how the neuron responds to a signal from a neighboring neuron and may alter how strong the connections between the neurons are. On the other hand, FMRP in the cell body modulated the activities of mRNAs encoding proteins that in turn regulate the activities of genes. These findings change the way we think about how memory may work by suggesting that groups of mRNAs encoding proteins with certain activities are found in distinct parts of a single neuron. These observations offer new ways to approach intellectual disabilities and autism spectrum disorder.


Asunto(s)
Cuerpo Celular/fisiología , Dendritas/fisiología , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/genética , Regulación de la Expresión Génica , Células Piramidales/fisiología , ARN Mensajero/genética , Animales , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Plasticidad Neuronal/fisiología , Células Piramidales/clasificación , Transcriptoma
16.
PLoS One ; 16(6): e0252949, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34170927

RESUMEN

To address the need for simple, safe, sensitive, and scalable SARS-CoV-2 tests, we validated and implemented a PCR test that uses a saliva collection kit use at home. Individuals self-collected 300 µl saliva in vials containing Darnell Rockefeller University Laboratory (DRUL) buffer and extracted RNA was assayed by RT-PCR (the DRUL saliva assay). The limit of detection was confirmed to be 1 viral copy/µl in 20 of 20 replicate extractions. Viral RNA was stable in DRUL buffer at room temperature up to seven days after sample collection, and safety studies demonstrated that DRUL buffer immediately inactivated virus at concentrations up to 2.75x106 PFU/ml. Results from SARS-CoV-2 positive nasopharyngeal (NP) swab samples collected in viral transport media and assayed with a standard FDA Emergency Use Authorization (EUA) test were highly correlated with samples placed in DRUL buffer. Direct comparison of results from 162 individuals tested by FDA EUA oropharyngeal (OP) or NP swabs with co-collected saliva samples identified four otherwise unidentified positive cases in DRUL buffer. Over six months, we collected 3,724 samples from individuals ranging from 3 months to 92 years of age. This included collecting weekly samples over 10 weeks from teachers, children, and parents from a pre-school program, which allowed its safe reopening while at-risk pods were quarantined. In sum, we validated a simple, sensitive, stable, and safe PCR-based test using a self-collected saliva sample as a valuable tool for clinical diagnosis and screening at workplaces and schools.


Asunto(s)
Prueba de Ácido Nucleico para COVID-19 , COVID-19 , SARS-CoV-2 , Saliva/virología , Instituciones Académicas , Manejo de Especímenes , COVID-19/diagnóstico , COVID-19/genética , Niño , Femenino , Humanos , Masculino
17.
Neuron ; 101(4): 707-720.e5, 2019 02 20.
Artículo en Inglés | MEDLINE | ID: mdl-30638744

RESUMEN

RNA-binding proteins (RBPs) regulate genetic diversity, but the degree to which they do so in individual cell types in vivo is unknown. We developed NOVA2 cTag-crosslinking and immunoprecipitation (CLIP) to generate functional RBP-RNA maps from different neuronal populations in the mouse brain. Combining cell type datasets from Nova2-cTag and Nova2 conditional knockout mice revealed differential NOVA2 regulatory actions on alternative splicing (AS) on the same transcripts expressed in different neurons. This includes functional differences in transcripts expressed in cortical and cerebellar excitatory versus inhibitory neurons, where we find NOVA2 is required for, respectively, development of laminar structure, motor coordination, and synapse formation. We also find that NOVA2-regulated AS is coupled to NOVA2 regulation of intron retention in hundreds of transcripts, which can sequester the trans-acting splicing factor PTBP2. In summary, cTag-CLIP complements single-cell RNA sequencing (RNA-seq) studies by providing a means for understanding RNA regulation of functional cell diversity.


Asunto(s)
Empalme Alternativo , Antígenos de Neoplasias/genética , Cerebelo/embriología , Corteza Cerebral/embriología , Neurogénesis , Neuronas/metabolismo , Proteínas de Unión al ARN/genética , Animales , Antígenos de Neoplasias/metabolismo , Células Cultivadas , Cerebelo/citología , Cerebelo/fisiología , Corteza Cerebral/citología , Potenciales Postsinápticos Excitadores , Femenino , Potenciales Postsinápticos Inhibidores , Masculino , Ratones , Ratones Endogámicos C57BL , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Antígeno Ventral Neuro-Oncológico , Neuronas/citología , Neuronas/fisiología , Proteína de Unión al Tracto de Polipirimidina/genética , Proteína de Unión al Tracto de Polipirimidina/metabolismo , Proteínas de Unión al ARN/metabolismo
18.
Elife ; 82019 12 20.
Artículo en Inglés | MEDLINE | ID: mdl-31860442

RESUMEN

Loss of the RNA binding protein FMRP causes Fragile X Syndrome (FXS), the most common cause of inherited intellectual disability, yet it is unknown how FMRP function varies across brain regions and cell types and how this contributes to disease pathophysiology. Here we use conditional tagging of FMRP and CLIP (FMRP cTag CLIP) to examine FMRP mRNA targets in hippocampal CA1 pyramidal neurons, a critical cell type for learning and memory relevant to FXS phenotypes. Integrating these data with analysis of ribosome-bound transcripts in these neurons revealed CA1-enriched binding of autism-relevant mRNAs, and CA1-specific regulation of transcripts encoding circadian proteins. This contrasted with different targets in cerebellar granule neurons, and was consistent with circadian defects in hippocampus-dependent memory in Fmr1 knockout mice. These findings demonstrate differential FMRP-dependent regulation of mRNAs across neuronal cell types that may contribute to phenotypes such as memory defects and sleep disturbance associated with FXS.


Asunto(s)
Trastorno Autístico/metabolismo , Región CA1 Hipocampal/metabolismo , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/genética , Síndrome del Cromosoma X Frágil/genética , Trastornos de la Memoria/genética , Células Piramidales/metabolismo , Animales , Trastorno Autístico/genética , Trastorno Autístico/fisiopatología , Región CA1 Hipocampal/citología , Cerebelo/citología , Cerebelo/metabolismo , Relojes Circadianos/genética , Relojes Circadianos/fisiología , Modelos Animales de Enfermedad , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/metabolismo , Síndrome del Cromosoma X Frágil/metabolismo , Síndrome del Cromosoma X Frágil/fisiopatología , Regulación de la Expresión Génica , Humanos , Trastornos de la Memoria/metabolismo , Trastornos de la Memoria/fisiopatología , Ratones Endogámicos C57BL , Ratones Noqueados , Neuronas/metabolismo
19.
Neuron ; 104(2): 256-270.e5, 2019 10 23.
Artículo en Inglés | MEDLINE | ID: mdl-31416668

RESUMEN

Familial Alzheimer's disease (fAD) results from mutations in the amyloid precursor protein (APP) and presenilin (PSEN1 and PSEN2) genes. Here we leveraged recent advances in induced pluripotent stem cell (iPSC) and CRISPR/Cas9 genome editing technologies to generate a panel of isogenic knockin human iPSC lines carrying APP and/or PSEN1 mutations. Global transcriptomic and translatomic profiling revealed that fAD mutations have overlapping effects on the expression of AD-related and endocytosis-associated genes. Mutant neurons also increased Rab5+ early endosome size. APP and PSEN1 mutations had discordant effects on Aß production but similar effects on APP ß C-terminal fragments (ß-CTFs), which accumulate in all mutant neurons. Importantly, endosomal dysfunction correlated with accumulation of ß-CTFs, not Aß, and could be rescued by pharmacological modulation of ß-secretase (BACE). These data display the utility of our mutant iPSCs in studying AD-related phenotypes in a non-overexpression human-based system and support mounting evidence that ß-CTF may be critical in AD pathogenesis.


Asunto(s)
Enfermedad de Alzheimer/genética , Péptidos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Endocitosis/genética , Endosomas/metabolismo , Neuronas/metabolismo , Fragmentos de Péptidos/metabolismo , Presenilina-1/genética , Enfermedad de Alzheimer/patología , Secretasas de la Proteína Precursora del Amiloide , Ácido Aspártico Endopeptidasas , Sistemas CRISPR-Cas , Línea Celular , Endosomas/patología , Perfilación de la Expresión Génica , Técnicas de Sustitución del Gen , Heterocigoto , Homocigoto , Humanos , Células Madre Pluripotentes Inducidas , Mutación , Tamaño de los Orgánulos , Fenotipo , Proteómica , Proteínas de Unión al GTP rab5/metabolismo
20.
Nat Genet ; 51(6): 973-980, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-31133750

RESUMEN

We address the challenge of detecting the contribution of noncoding mutations to disease with a deep-learning-based framework that predicts the specific regulatory effects and the deleterious impact of genetic variants. Applying this framework to 1,790 autism spectrum disorder (ASD) simplex families reveals a role in disease for noncoding mutations-ASD probands harbor both transcriptional- and post-transcriptional-regulation-disrupting de novo mutations of significantly higher functional impact than those in unaffected siblings. Further analysis suggests involvement of noncoding mutations in synaptic transmission and neuronal development and, taken together with previous studies, reveals a convergent genetic landscape of coding and noncoding mutations in ASD. We demonstrate that sequences carrying prioritized mutations identified in probands possess allele-specific regulatory activity, and we highlight a link between noncoding mutations and heterogeneity in the IQ of ASD probands. Our predictive genomics framework illuminates the role of noncoding mutations in ASD and prioritizes mutations with high impact for further study, and is broadly applicable to complex human diseases.


Asunto(s)
Trastorno del Espectro Autista/genética , Aprendizaje Profundo , Predisposición Genética a la Enfermedad , Genoma Humano , Genómica , Mutación , ARN no Traducido , Algoritmos , Alelos , Trastorno del Espectro Autista/diagnóstico , Biología Computacional/métodos , Expresión Génica , Regulación de la Expresión Génica , Genes Reporteros , Estudios de Asociación Genética , Genómica/métodos , Humanos , Fenotipo , Procesamiento Postranscripcional del ARN , Transcripción Genética
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