RESUMO
To understand how a protective immune response against SARS-CoV-2 develops over time, we integrated phenotypic, transcriptional and repertoire analyses on PBMCs from mild and severe COVID-19 patients during and after infection, and compared them to healthy donors (HD). A type I IFN-response signature marked all the immune populations from severe patients during the infection. Humoral immunity was dominated by IgG production primarily against the RBD and N proteins, with neutralizing antibody titers increasing post infection and with disease severity. Memory B cells, including an atypical FCRL5+ T-BET+ memory subset, increased during the infection, especially in patients with mild disease. A significant reduction of effector memory, CD8+ T cells frequency characterized patients with severe disease. Despite such impairment, we observed robust clonal expansion of CD8+ T lymphocytes, while CD4+ T cells were less expanded and skewed toward TCM and TH2-like phenotypes. MAIT cells were also expanded, but only in patients with mild disease. Terminally differentiated CD8+ GZMB+ effector cells were clonally expanded both during the infection and post-infection, while CD8+ GZMK+ lymphocytes were more expanded post-infection and represented bona fide memory precursor effector cells. TCR repertoire analysis revealed that only highly proliferating T cell clonotypes, which included SARS-CoV-2-specific cells, were maintained post-infection and shared between the CD8+ GZMB+ and GZMK+ subsets. Overall, this study describes the development of immunity against SARS-CoV-2 and identifies an effector CD8+ T cell population with memory precursor-like features.
Assuntos
COVID-19/genética , COVID-19/imunologia , Interações Hospedeiro-Patógeno/imunologia , Imunofenotipagem , SARS-CoV-2/imunologia , Transcriptoma , Adulto , Idoso , Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Biomarcadores , COVID-19/virologia , Plasticidade Celular/genética , Plasticidade Celular/imunologia , Evolução Clonal/imunologia , Feminino , Perfilação da Expressão Gênica , Humanos , Isotipos de Imunoglobulinas/imunologia , Memória Imunológica , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismoRESUMO
The histone demethylase LSD1 is a key chromatin regulator that is often deregulated in cancer. Its ortholog, dLsd1 plays a crucial role in Drosophila oogenesis; however, our knowledge of dLsd1 function is insufficient to explain its role in the ovary. Here, we have performed genome-wide analysis of dLsd1 binding in the ovary, and we document that dLsd1 is preferentially associated to the transcription start site of developmental genes. We uncovered an unanticipated interplay between dLsd1 and the GATA transcription factor Serpent and we report an unexpected role for Serpent in oogenesis. Besides, our transcriptomic data show that reducing dLsd1 levels results in ectopic transposable elements (TE) expression correlated with changes in H3K4me2 and H3K9me2 at TE loci. In addition, our results suggest that dLsd1 is required for Piwi dependent TE silencing. Hence, we propose that dLsd1 plays crucial roles in establishing specific gene expression programs and in repressing transposons during oogenesis.
Assuntos
Elementos de DNA Transponíveis/genética , Proteínas de Drosophila/genética , Fatores de Transcrição GATA/genética , Oogênese/genética , Oxirredutases N-Desmetilantes/genética , Animais , Proteínas Argonautas/genética , Cromatina/genética , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Feminino , Regulação da Expressão Gênica no Desenvolvimento/genética , Genes Controladores do Desenvolvimento/genética , Histonas/genética , Ovário/crescimento & desenvolvimento , Ovário/metabolismo , Sítio de Iniciação de TranscriçãoRESUMO
N6-methyladenosine (m6A) is the most abundant RNA modification. It has been involved in the regulation of RNA metabolism, including degradation and translation, in both physiological and disease conditions. A recent study showed that m6A-mediated degradation of key transcripts also plays a role in the control of T cells homeostasis and IL-7 induced differentiation. We re-analyzed the omics data from that study and, through the integrative analysis of total and nascent RNA-seq data, we were able to comprehensively quantify T cells RNA dynamics and how these are affected by m6A depletion. In addition to the expected impact on RNA degradation, we revealed a broader effect of m6A on RNA dynamics, which included the alteration of RNA synthesis and processing. Altogether, the combined action of m6A on all major steps of the RNA life-cycle closely re-capitulated the observed changes in the abundance of premature and mature RNA species. Ultimately, our re-analysis extended the findings of the initial study, focused on RNA stability, and proposed a yet unappreciated role for m6A in RNA synthesis and processing dynamics.