RESUMO
Long-lived antibody-secreting plasma cells are essential to establish humoral memory against pathogens. While a regulatory transcription factor network has been established in plasma cell differentiation, the regulatory role of miRNAs remains enigmatic. We have recently identified miR-148a as the most abundant miRNA in primary mouse and human plasma cells. To determine whether this plasma cell signature miRNA controls the in vivo development of B cells into long-lived plasma cells, we established mice with genomic, conditional, and inducible deletions of miR-148a. The analysis of miR-148a-deficient mice revealed reduced serum Ig, decreased numbers of newly formed plasmablasts and reduced CD19-negative, CD93-positive long-lived plasma cells. Transcriptome and metabolic analysis revealed an impaired glucose uptake, a reduced oxidative phosphorylation-based energy metabolism, and an altered abundance of homing receptors CXCR3 (increase) and CXCR4 (reduction) in miR-148a-deficient plasma cells. These findings support the role of miR-148a as a positive regulator of the maintenance of long-lived plasma cells.
Assuntos
Diferenciação Celular/genética , Metabolismo Energético , Regulação da Expressão Gênica , MicroRNAs/genética , Plasmócitos/metabolismo , Animais , Antígenos CD19/metabolismo , Linfócitos B/citologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Biomarcadores , Medula Óssea/imunologia , Medula Óssea/metabolismo , Diferenciação Celular/imunologia , Sobrevivência Celular/genética , Sobrevivência Celular/imunologia , Epitopos de Linfócito B/imunologia , Técnicas de Silenciamento de Genes , Imunofenotipagem , Contagem de Linfócitos , Camundongos , Camundongos Knockout , Plasmócitos/citologia , Plasmócitos/imunologia , Interferência de RNARESUMO
We review the importance of small non-coding microRNAs for the generation of germinal center B cells and their differentiation in antibody-secreting plasma cells. In the last part, we briefly elucidate the role of microRNAs in some plasma cell disorders.
Assuntos
Formação de Anticorpos , MicroRNAs , Plasmócitos/imunologia , Animais , Autoimunidade , Diferenciação Celular , Centro Germinativo/imunologia , Humanos , Doenças do Sistema Imunitário/imunologiaRESUMO
We provide a robust four-color fluorescence-based flow cytometry protocol that distinguishes viable dividing plasmablasts from nondividing plasma cells and, based on CD19 surface abundance, identifies two mature plasma cell populations in the spleen and the bone marrow of mice.
Assuntos
Citometria de Fluxo/métodos , Imunofenotipagem/métodos , Plasmócitos/classificação , Plasmócitos/imunologia , Coloração e Rotulagem/métodos , Animais , Antígenos CD19/análise , Células da Medula Óssea/imunologia , Diferenciação Celular , Proteínas de Fluorescência Verde , Imunofenotipagem/instrumentação , Antígenos Comuns de Leucócito/análise , Camundongos , Fator 1 de Ligação ao Domínio I Regulador Positivo , Baço/imunologia , Sindecana-1/análise , Fatores de Transcrição/análiseRESUMO
We have previously shown that the microRNA (miRNA) processor complex consisting of the RNAse Drosha and the DiGeorge Critical Region (DGCR) 8 protein is essential for B cell maturation. To determine whether miRNA processing is required to initiate T cell-mediated antibody responses, we deleted DGCR8 in maturing B2 cells by crossing a mouse with loxP-flanked DGCR8 alleles with a CD23-Cre mouse. As expected, non-immunized mice showed reduced numbers of mature B2 cells and IgG-secreting cells and diminished serum IgG titers. In accordance, germinal centers and antigen-specific IgG-secreting cells were absent in mice immunized with T-dependent antigens. Therefore, DGCR8 is required to mount an efficient T-dependent antibody response. However, DGCR8 deletion in B1 cells was incomplete, resulting in unaltered B1 cell numbers and normal IgM and IgA titers in DGCR8-knock-out mice. Therefore, this mouse model could be used to analyze B1 responses in the absence of functional B2 cells.