Forced expression of a single transcription factor, FOXN1, can regenerate an aged thymus, leading to normal production and differentiation of T cells.
Thymus is the most rapidly aging tissue. In our previous blog we discussed how age-related thymic involution is associated with immunosenescence, a degeneration of the immune system primarily due to reduction in naïve T cells population. The compromised immune system causes the marked reduction in responsiveness to infectious diseases in old adults.
A study lead by researchers at Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, showed restoration of a fully involute thymus in aged mice model. The rejuvenated thymus was able to reinstate its ability to create naive T-cells and also able to differentiate into mature T lymphocytes (T cells). T cells play a very important role in fighting against the infection. This significant finding is an inspiring archetype in aging related therapies or regenerative medicine.
Recently, it has been found that thymic epithelial cell (TEC)-specific transcription factor Forkhead box N1 (FOXN1) is an important component for regulating the age-related involution mechanism. Researchers showed that the forced expression of FOXN1, which is a key regulator of TEC lineage specification can regenerate a robust thymus from the fully involute thymus. The rejuvenated thymus closely resembles with the juvenile thymus in terms of architecture and gene expression profile.
The thymus is characterized by increased thymopoiesis and increased naive T cell output and researchers further show that FOXN1-mediated regeneration stems from an enlarged TEC compartment, rebuilt from progenitor TECs. The study offers a hope that thymus regeneration in aged adults or in patients with compromised immunity (because of undeveloped thymus) can be directed by manipulation of a single transcription factor. This advancement in regenerative medicine can lay the first stone by invigorating the aged or undeveloped thymus. HemaCare, a leading provider of high quality blood products to researchers for over 35 years, supplies all kinds of lymphocytes and immune cell products to suit your need.
 Murasko, D. M., and J. Jiang. 2005. Response of aged mice to primary virus infections. Immunol. Rev. 205: 285–296.
 Romano R, Palamaro L, Fusco A, Giardino G, Gallo V, Del Vecchio L, Pignata C. FOXN1: A Master Regulator Gene of Thymic Epithelial Development Program. Front Immunol. 2013 Jul 12;4:187.