FIGURE 3.

Ghrelin regulates epithelial-to mesenchymal transition in the thymus. A, the FoxN1-Cre-expressing mice were bred with indicator mice that contain the LacZ gene integrated into the ubiquitous ROSA26 locus downstream of a floxed transcriptional STOP sequence. Expression of Cre recombinase in TECs excised the floxed STOP sequence and indelibly marked the cells with LacZ. B, immunofluorescence triple labeling in 3-month-old FoxN1Cre; ROSA26RstoplacZ reporter mice thymus with DAPI (blue), antibodies to β-galactosidase (indelibly marked TEC), and FSP-1 (EMT marker). The EMT is evident by medullary expression and co-localization of FSP1 with β-galactosidase. Thymic cryosections of 3-month-old FoxN1Cre;ROSA26RstoplacZ mice were triple labeled with antibodies to FSP1 (blue), β-galactosidase (red), and neutral lipid by LipidTox (green) or PPARγ (green). A representative image (n = 4) shows lipid expression within a β-galactosidase and FSP1 co-expressing cells in the thymic PVS.