Figure 8. Premature thymic involution and over-activation of NF-κB in the thymus of K5-CYLDC/S mice. (A-C) Analysis of the expression of the transgene by immunostaining with a specific antibody against the HA tag. Expression of HA is detected in the medulla of the thymus of the K5-CYLDC/S mice (B), following the expression pattern of the K5 (C), while it is not detected in the Controls (A). (D) Analysis by WB of the expression of the transgene in protein extracts from isolated thymic cells of mice of 3.5-month-old. Note the overactivation of NF-κB (increased levels of P-p65) in the K5-CYLDC/S mice. Mann-Whitney U test was used for statistical analysis. (*p<0.05). (E, F) Histological analysis of the thymus of 2.5-month-old mice. Observe the expansion of the cortical zone and reduction of the medullar region in the thymus of transgenic mice (F). (G, H) H&E staining of 3.5-month-old Control (G) and K5-CYLDC/S mice (H) thymus. A representative image of the thymic atrophy and infiltration of white adipose tissue in the thymus of transgenic mice (H) is shown. (I) Western blot showing the decreased expression of CYLD with age in the thymus of control mice. M, medulla. C, cortex. a, adipose tissue. Scale bars: 200 μm (A, B); 300 μm (C); 350 μm (E-H).