Year: 2015
Type: article
Abstract: Our research in the past few years has identified B cell-specific biomarkers able to predict optimal Ab responses in both young and elderly individuals. These biomarkers are activation-induced cytidine deaminase (AID), the enzyme of class switch recombination and somatic hypermutation; the transcription factor E47, crucial for AID expression; and the ability to generate optimal memory B cells. Moreover, we have found that the increased proinflammatory status of the elderly, both in sera and intrinsic to B cells, negatively impacts B cell function. We have now investigated whether particular inflammatory microRNAs (miRs) contribute to decreased E47 and AID in aged B cells. Our data indicate that E47 and AID mRNA stability is lower in stimulated B cells from elderly individuals. We measured the expression of two miRs crucial for class switch recombination, miR-155 and miR-16, in human unstimulated B cells from young and elderly individuals with the rationale that increases in these before stimulation would decrease E47/AID upon cell activation. We found these miRs and B cell-intrinsic inflammation upregulated in aged unstimulated B cells and negatively associated with AID in the same B cells after stimulation with CpG. We propose that the downregulation of AID in aged human B cells may occur through binding of miR-155 to the 3'-untranslated regions of AID mRNA and/or binding of miR-16 to the 3'-untranslated regions of E47 mRNA, as well as at the transcriptional level of less E47 for AID. Our results indicate novel molecular pathways leading to reduced B cell function with aging.
Source: The Journal of Immunology
Authors: Daniela Frasca, Alain Diaz, Maria Romero, Franco Ferracci, Bonnie B Blomberg
Institution: University of Miami
Language: English
Topic: T-cell and B-cell Immunology
Subfield: Immunology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: bronze
Awards: Regulation of B Lymphocyte Defects in Senescent Humans, Regulation of Immunoglobulin Class Switch in Aged Mice, G4110906, Molecular mechanisms for TNF-mediated inhibition of B lymphocyte function, Regulation of primary and memory B cell vaccine responses in the elderly, G9000052191, Micro-RNAs: a new mechanism negatively regulating B cell responses in the elderly
OpenAlex ID: W2158271393