Fig. 6.

PGE₂ increased Paneth cell numbers in postnatal wild-type (WT), Toll-like receptor 4 (TLR4)^f/fLysM-Cre, and cyclooxygenase 2 (COX2)^−/− mice, but not in postnatal epidermal growth factor receptor (EGFR)^f/fVil-Cre/ERT2 mice. A: photomicrographs show lysozyme-expressing Paneth cells in small intestines of control and 16,16-dimethyl PGE₂ (dmPGE₂)-treated 14-dayold mice. B: compared with WT mice, the number of Paneth cells/crypt section was reduced in WT mice depleted of macrophages due to clodronate treatment, in TLR4^f/fLysM-Cre mice having constitutive deletion of TLR4 in macrophages, in COX2^−/− mice, and in EGFR^f/fVil-Cre/ERT2 mice with tamoxifen-induced deletion of EGFR in intestinal epithelial cells. Treatment with dmPGE₂ increased Paneth cell numbers in WT mice, in mice deficient in myeloid TLR4, and in mice deficient in COX2 but not in mice deficient in epithelial cell EGFR. Values are means ± SE for 6 mice/treatment group. ***P < 0.001 compared with similar mice not treated with dmPGE₂. +++P < 0.001 compared with WT control mice.