Bioinformatics Seminar
Time: 11AM
Venue: Davis Auditorium and Online
2 July 2024
Exploring the hierarchical chromatin Landscape of Immune Memory Cells
Hannah CoughlanWEHI Bioinformatics
Adaptive immune memory is a specialized mechanism where immune cells remember previous encounters with pathogens, allowing for a quicker and more effective response upon re-exposure. Little is known about the epigenetics of memory immune cells especially compared to their naïve counterparts. Here we generated and integrated genome organisation (through HiC), chromatin accessibility (ATAC-Seq) and transcriptomic (RNA-Seq) data to unravel the intricate hierarchical chromatin landscape of the two arms of adaptive murine memory (T and B cells). Through statistically robust differential analysis of RNA-seq, ATAC-seq and HiC data, we observe that the genome of B cells undergoes fewer changes upon memory formation compared to T cells. In both transcriptomic and chromatin accessibility analyses, we find common changes occurring in both T and B cells as they form memory cells, despite these cells very different functions. These changes form part of a larger memory state convergence, with the genome organisation, transcriptomic and chromatin accessibility profiles of memory T being more like B cells than their naïve T cell counterparts. Interestingly we find shared intergenic regulators that increase in accessibility with memory formation and possess specific transcription factor motifs from the AP-1 complex. This indicates there is a memory epigenetic state independent of cell type. Our multi-omic analysis, not only unveils the hierarchical chromatin landscape governing immune memory cells but also offers insights into the differential epigenetic and transcriptional regulation within B and T cells. These discoveries have profound implications for our understanding of immune memory and its impact on long-term immunity, vaccine responses, and immunotherapies.