Global and Local Changes in Nuclear Shape upon T Cell Activation

T cells, crucial players in the adaptive immune response, become activated when receptors on their surface recognize and bind to pathogenic peptides presented by antigen-presenting cells. Activation triggers a series of dynamic changes in cellular morphology, including notable alterations to nuclear shape and chromatin organization. Here, we use confocal microscopy to study T cells activated on ligand-coated planar surfaces. We develop an analysis platform to generate 3D reconstructions of nuclei and characterize nuclear shape. Nuclear morphology is characterized as a function of T cell activation as well as chemical and mechanical perturbations to the nucleus. We find that the actin cytoskeleton plays an important role in nuclear deformation during T cell activation and that perturbations of chromatin compaction affect nuclear shape. Our findings further reveal that the centrosome, the microtubule-organizing center, tends to be located near a prominent invagination of the nucleus. We characterize how this nuclear invagination and the centrosome polarize towards the activating surface. We also apply our analysis platform to quantify the intranuclear distribution of epigenetic markers of transcriptional repression or activation. These findings deepen our understanding of nuclear organization and dynamics during T cell activation and establish a foundation for further exploring how nuclear architecture may regulate gene expression and immune function.