Key points from article :
T cells, from bone marrow, learn to attack antigens, not body tissues in the thymus.
With aging, thymic tissues are replaced by fat tissue, decreasing its function, through a process which is known as involution.
Thymus is regulated by thymic epithelial cells (TECs), dysregulation of which increases risks of infections and autoimmune disorders.
Dendritic cells (mDC), of the adaptive immune system, express Jagged ligands, which bind to Notch protein, expressed by TECs, essential for the functioning of the thymus.
mDcs through intercellular communication activates the Notch pathway leading to the death of TECs.
Intrathymic injection of mDCs or jagged ligand in mice resulted in atrophy of the thymus which suggests that aging-related thymus degeneration can be induced either by mass migration or by a few but constantly homing mDCs.
This study does not examine any potential treatments, but it paves way for the development of signaling-based interventions to slow and/or reverse thymic involution.
Study published in Nature Communications’ Cell Death Discovery by Qixiang Shao et.al.s from Jiangsu University.