KGF signaling engages NF-κB and p53 in TECs. (A) Proliferation of cells present in thymocyte-depleted E15.5 fetal thymic stromal cell preparations was assessed in culture by 3H-thymidine incorporation (cpm). The x-axis indicates the time (in hours) after exposure to exogenous KGF (100 ng/mL, ○) or HBSS (▪); n = 6 experiments. Mean ± SD; *P < .05. (B) Transcripts for Wnt5b, Wnt10b, BMP2, and BMP4 were quantified by qRT-PCR after 24 hours of culture. Expression levels in KGF-treated mice (⊡) were compared with those in control mice treated with HBSS (x-fold change KGF vs HBSS, whereby the expression levels in the latter were set as 1.0; dotted line). A total of 3 experiments were performed, whereby material from 15 mice was pooled for each experiment. (C) Transcripts for Wnt10b were quantified by qRT-PCR in alymphoid E15.5 fetal thymic lobes exposed in culture for 24 hours to either KGF (⊡) or HBSS (▪) in the presence or absence of the following inhibitors: the selective IκB kinase (IKK) inhibitor PS1145, the farnesyltransferase (FTase) inhibitor L-778123, which blocks the Ras pathway, or PFT102, a specific small-molecular inhibitor of p53. Transcription levels were compared with control cultures exposed to HBSS but not supplemented with any of the inhibitors (dotted line = 1.0). Three independent experiments were performed; mean ± SD. *P < .05 versus HBSS control, with 6 lobes examined per time point (A), 3 lobes per group and experiment (B, total of 3 experiments), and 4 experiments (C).
