Regulatory B cell metabolism and ageing: Integrating experiment and data analysis

Regulatory B-cells (Bregs) are an important component of immune-tolerance, they are
numerically and phenotypically altered with increasing age and in cancer1-3. Breg
differentiation and function, unlike other B cell populations, requires oxidative
phosphorylation and high mitochrondria capacity and we have shown that interference
with these metabolic pathways abrogates Bregs function4. Declining mitochondrial
quality and metabolic activity are associated with normal aging, correlating with the
declining of the immune function5. Here we will investigate how age-related
mitochondrial/metabolic changes in Bregs affect their differentiation into plasma cells
and their suppressive function. Aim-1. Define age-related metabolic changes in B-cells
and Bregs (Mauri-Bradford UCL). PBMC/splenocytes from 20 to 70+ year-old donors will
be stained with antibodies defining B-cell subsets and metabolic pathways will be
analysed by multiparameter flow cytometry. B-cell glycolysis and respiration rates will
also be assessed by seahorse. Aim-2. Define age-related changes in the Breg
metabolic transcriptome. (Fraternali-Ng King's). We will sort Bregs from the
spleens/blood of young (20-25y/o) and aged (70+) (n=3) adults and perform singlecell-
RNA-sequencing. We propose a multi-disciplinary approach to interrogate agerelated
changes of Breg metabolism through analysing the generated scRNA-seq
datasets using state-of-the-art computational algorithms followed by experimental
validation. Descriptions of key Breg cellular/metabolomic states identified by
computational methods will be substantiated, integrating different biological
annotations (protein-protein interactions, pathways, metabolomics) (Fraternali-Ng's).
We will also perturb gene/metabolite drivers with genetic/pharmacological approaches
to recapitulate or rescue age-associated Breg deficits (Mauri-Bradford's). We anticipate
improved understanding of B cells, Breg metabolism and its deregulation in ageing.
Significance: Bregs are an essential component of the immune system and
understanding how changes in their metabolic requirements in ageing affects their
regulatory function is crucial to a full understanding of immune homeostasis in old
age.