RESUMEN
The upper airway is an important site of infection, but immune memory in the human upper airway is poorly understood, with implications for COVID-19 and many other human diseases1-4. Here we demonstrate that nasal and nasopharyngeal swabs can be used to obtain insights into these challenging problems, and define distinct immune cell populations, including antigen-specific memory B cells and T cells, in two adjacent anatomical sites in the upper airway. Upper airway immune cell populations seemed stable over time in healthy adults undergoing monthly swabs for more than 1 year, and prominent tissue resident memory T (TRM) cell and B (BRM) cell populations were defined. Unexpectedly, germinal centre cells were identified consistently in many nasopharyngeal swabs. In subjects with SARS-CoV-2 breakthrough infections, local virus-specific BRM cells, plasma cells and germinal centre B cells were identified, with evidence of local priming and an enrichment of IgA+ memory B cells in upper airway compartments compared with blood. Local plasma cell populations were identified with transcriptional profiles of longevity. Local virus-specific memory CD4+ TRM cells and CD8+ TRM cells were identified, with diverse additional virus-specific T cells. Age-dependent upper airway immunological shifts were observed. These findings provide new understanding of immune memory at a principal mucosal barrier tissue in humans.
Asunto(s)
Memoria Inmunológica , Células B de Memoria , Células T de Memoria , Mucosa Nasal , Nasofaringe , SARS-CoV-2 , Adulto , Humanos , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/citología , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/citología , COVID-19/inmunología , COVID-19/virología , Centro Germinal/inmunología , Centro Germinal/citología , Inmunoglobulina A/inmunología , Memoria Inmunológica/inmunología , Células B de Memoria/inmunología , Células T de Memoria/inmunología , Mucosa Nasal/inmunología , Mucosa Nasal/virología , Nasofaringe/virología , Nasofaringe/inmunología , Células Plasmáticas/inmunología , Células Plasmáticas/citología , SARS-CoV-2/inmunologíaRESUMEN
A major unanswered question in neuroscience is whether there exists genomic variability between individual neurons of the brain, contributing to functional diversity or to an unexplained burden of neurological disease. To address this question, we developed a method to amplify genomes of single neurons from human brains. Because recent reports suggest frequent LINE-1 (L1) retrotransposition in human brains, we performed genome-wide L1 insertion profiling of 300 single neurons from cerebral cortex and caudate nucleus of three normal individuals, recovering >80% of germline insertions from single neurons. While we find somatic L1 insertions, we estimate <0.6 unique somatic insertions per neuron, and most neurons lack detectable somatic insertions, suggesting that L1 is not a major generator of neuronal diversity in cortex and caudate. We then genotyped single cortical cells to characterize the mosaicism of a somatic AKT3 mutation identified in a child with hemimegalencephaly. Single-neuron sequencing allows systematic assessment of genomic diversity in the human brain.
Asunto(s)
Núcleo Caudado/citología , Corteza Cerebral/citología , Elementos de Nucleótido Esparcido Largo , Mutación , Neuronas/metabolismo , Análisis de la Célula Individual , Núcleo Caudado/metabolismo , Corteza Cerebral/metabolismo , Niño , Cromosomas Humanos Par 18 , Estudio de Asociación del Genoma Completo , Humanos , Masculino , Malformaciones del Desarrollo Cortical/genética , Malformaciones del Desarrollo Cortical/patología , Mosaicismo , Proteínas Proto-Oncogénicas c-akt/genética , TrisomíaRESUMEN
Akt kinases translate various external cues into intracellular signals that control cell survival, proliferation, metabolism and differentiation. This review discusses the requirement for Akt and its targets in determining the fate and function of T cells. We discuss the importance of Akt at various stages of T cell development including ß-selection during which Akt fulfills the energy requirements of highly proliferative DN3 cells. Akt also plays an integral role in CD8 T cell biology where its regulation of Foxo transcription factors and mTORC1 metabolic activity controls effector versus memory CD8 T cell differentiation. Finally, Akt promotes the differentiation of naïve CD4 T cells into Th1, Th17 and Tfh cells but inhibits the development of Treg cells. We also highlight how modulating Akt in T cells is a promising avenue for enhancing cell-based cancer immunotherapy.
RESUMEN
Neurogenesis is a highly-regulated process occurring in the dentate gyrus that has been linked to learning, memory, and antidepressant efficacy. MicroRNAs (miRNAs) have been previously shown to play an important role in the regulation of neuronal development and neurogenesis in the dentate gyrus via modulation of gene expression. However, this mode of regulation is both incompletely described in the literature thus far and highly multifactorial. In this study, we designed sensors and detected relative levels of expression of 10 different miRNAs and found miR-338-3p was most highly expressed in the dentate gyrus. Comparison of miR-338-3p expression with neuronal markers of maturity indicates miR-338-3p is expressed most highly in the mature neuron. We also designed a viral "sponge" to knock down in vivo expression of miR-338-3p. When miR-338-3p is knocked down, neurons sprout multiple primary dendrites that branch off of the soma in a disorganized manner, cellular proliferation is upregulated, and neoplasms form spontaneously in vivo. Additionally, miR-338-3p overexpression in glioblastoma cell lines slows their proliferation in vitro. Further, low miR-338-3p expression is associated with increased mortality and disease progression in patients with glioblastoma. These data identify miR-338-3p as a clinically relevant tumor suppressor in glioblastoma.
Asunto(s)
Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patología , Diferenciación Celular , Glioblastoma/genética , Glioblastoma/patología , MicroARNs/genética , Neuronas/patología , Animales , Línea Celular Tumoral , Proliferación Celular , Forma de la Célula , Giro Dentado/metabolismo , Giro Dentado/patología , Supervivencia sin Enfermedad , Regulación Neoplásica de la Expresión Génica , Técnicas de Silenciamiento del Gen , Proteína Ácida Fibrilar de la Glía/metabolismo , Humanos , Ratones Endogámicos C57BL , MicroARNs/metabolismo , Neuronas/metabolismo , Reproducibilidad de los Resultados , Resultado del TratamientoRESUMEN
OBJECTIVE: To identify the genetic cause of a syndrome causing cerebellar ataxia and eye movement abnormalities. METHODS: We identified 2 families with cerebellar ataxia, eye movement abnormalities, and global developmental delay. We performed genetic analyses including single nucleotide polymorphism genotyping, linkage analysis, array comparative genomic hybridization, quantitative PCR, and Sanger sequencing. We obtained eye movement recordings of mutant mice deficient for the ortholog of the identified candidate gene, and performed immunohistochemistry using human and mouse brain specimens. RESULTS: All affected individuals had ataxia, eye movement abnormalities, most notably tonic upgaze, and delayed speech and cognitive development. Homozygosity mapping identified the disease locus on chromosome 4q. Within this region, a homozygous deletion of GRID2 exon 4 in the index family and compound heterozygous deletions involving GRID2 exon 2 in the second family were identified. Grid2-deficient mice showed larger spontaneous and random eye movements compared to wild-type mice. In developing mouse and human cerebella, GRID2 localized to the Purkinje cell dendritic spines. Brain MRI in 2 affected children showed progressive cerebellar atrophy, which was more severe than that of Grid2-deficient mice. CONCLUSIONS: Biallelic deletions of GRID2 lead to a syndrome of cerebellar ataxia and tonic upgaze in humans. The phenotypic resemblance and similarity in protein expression pattern between humans and mice suggest a conserved role for GRID2 in the synapse organization between parallel fibers and Purkinje cells. However, the progressive and severe cerebellar atrophy seen in the affected individuals could indicate an evolutionarily unique role for GRID2 in the human cerebellum.
Asunto(s)
Ataxia Cerebelosa/genética , Trastornos de la Motilidad Ocular/genética , Receptores de Glutamato/genética , Adolescente , Animales , Niño , Preescolar , Exones/genética , Femenino , Genes Recesivos/genética , Humanos , Masculino , Ratones , Eliminación de Secuencia/genética , SíndromeRESUMEN
Hemimegalencephaly (HMG) is a developmental brain disorder characterized by an enlarged, malformed cerebral hemisphere, typically causing epilepsy that requires surgical resection. We studied resected HMG tissue to test whether the condition might reflect somatic mutations affecting genes critical to brain development. We found that two out of eight HMG samples showed trisomy of chromosome 1q, which encompasses many genes, including AKT3, a gene known to regulate brain size. A third case showed a known activating mutation in AKT3 (c.49GâA, creating p.E17K) that was not present in the patient's blood cells. Remarkably, the E17K mutation in AKT3 is exactly paralogous to E17K mutations in AKT1 and AKT2 recently discovered in somatic overgrowth syndromes. We show that AKT3 is the most abundant AKT paralog in the brain during neurogenesis and that phosphorylated AKT is abundant in cortical progenitor cells. Our data suggest that somatic mutations limited to the brain could represent an important cause of complex neurogenetic disease.