Journal: Developmental biology

Article Title: Retinoic acid selectively regulates Fgf10 expression and maintains cell identity in the prospective lung field of the developing foregut.

doi: 10.1016/j.ydbio.2004.04.039

Figure Lengend Snippet: Fig. 4. Whole mount ISH of Fgfr2b and Fgf10 mRNA in vivo and in foregut cultures. (A) Fgfr2b mRNA is expressed throughout the foregut endoderm including the respiratory tract in E9.5 embryos and in (B) control cultures. (B, C) Fgfr2b expression is not disrupted by BMS treatment. (D) At E8.5, Fgf10 is expressed in the mesoderm of thyroid; subsequently (E9.5), signals appear in lung and thyroid domains. (E) In control cultures, these domains are preserved. (F) BMS treatment of explants younger than the 15-somite stage, but not older than that (G), prevents Fgf10 mRNA expression in the presumptive respiratory mesoderm (*). RA (106 M) has no obvious effects on Fgf10 expression. Area between dotted lines (in yellow) corresponds to the region of disrupted Fgf10 expression. Scale bars in A and E represent 85 and 150 Am, respectively.

Article Snippet: In some experiments, heparin beads soaked in human recombinant FGF10 (100 ng/Al, R&D Systems) or PBS (buffer) were grafted onto foreguts after 48 h culture.

Techniques: In Vivo, Control, Expressing

Journal: Developmental biology

Article Title: Retinoic acid selectively regulates Fgf10 expression and maintains cell identity in the prospective lung field of the developing foregut.

doi: 10.1016/j.ydbio.2004.04.039

Figure Lengend Snippet: Fig. 6. Exogenous FGF10 rescues lung budding and epithelial differentiation in BMS-treated cultures. PCNA staining in sagittal sections (A, D) and whole mount ISH of Ttf1 (B, E) and Sp-C (C, F) in 6-day cultures engrafted with heparin beads (human recombinant FGF10, PBS buffer). (A) FGF10 beads induced lung bud formation, local PCNA labeling and expression of Ttf1 (B) and Sp-C mRNA (C) in BMS-treated explants. PBS beads failed to induce a local increase in proliferation (D) and had no detectable Ttf1 (E) or Sp-C (F) signals in the respiratory region of foregut. Note the preserved Ttf1 staining in thyroid (B, E). (G–J) Quantitative analysis of PCNA- and TUNEL-stained sections from BMS-treated explants in the lung field. (H) Engraftment of an FGF10 bead results in a significant increase in the relative number of PCNA-labeled cells in the adjacent endoderm (G) as compared to a PBS bead. Mesodermal PCNA (G) or TUNEL labeling (I) in endoderm or mesoderm is not altered by FGF10. Graphs (H, J) represent mean and standard error; *P < 0.05. Lu, lung; Th, thyroid. Scale bar in E represents 240 Am.

Article Snippet: In some experiments, heparin beads soaked in human recombinant FGF10 (100 ng/Al, R&D Systems) or PBS (buffer) were grafted onto foreguts after 48 h culture.

Techniques: Staining, Recombinant, Labeling, Expressing, TUNEL Assay

Journal: Developmental biology

Article Title: Retinoic acid selectively regulates Fgf10 expression and maintains cell identity in the prospective lung field of the developing foregut.

doi: 10.1016/j.ydbio.2004.04.039

Figure Lengend Snippet: Fig. 7. Lung agenesis and disrupted expression of Ttf1 protein and Fgf10 mRNA in the respiratory region of foregut of vitamin A-deficient rats (A–D). H&E and Ttf1 immunostaining of transverse sections of control RAS foregut demonstrates (A) ongoing tracheoesophageal separation with Ttf1 expression restricted to the ventrally located tracheal epithelium and, more caudally, (B) primary lung bud epithelium intensely labeled with Ttf1. (C) In RAD foregut, the tube is irregularly shaped (*) and shows low levels of Ttf1 expression in the ventral endoderm at the prospective respiratory region that failed to bud. (D) Strong Ttf1 signals, however, are present in the thyroid bud. (E, F) Isotopic ISH of Fgf10 mRNA in transverse sections at the level of the lung buds in control RAS demonstrates localized signal in the mesoderm of the lung (F, enlarged), limb and urogenital tract (ug). In RAD (G, H), Fgf10 expression is preserved in the limb and urogenital tract but is disrupted in the presumptive lung field of the foregut (H, high magnification). Es, esophagus; fl, forelimb; hl, hindlimb; Lu, lung; Th, thyroid; Tr, trachea; RAD, RA deficient; RAS, RA sufficient; ug, urogenital ridge. Dashed boxes in E and G delineate close-up views in F and H, respectively. Arrowheads represent signals; asterisks indicate areas that failed to bud or to express Fgf10. Scale bars in B and G represent 80 and 480 Am, respectively.

Article Snippet: In some experiments, heparin beads soaked in human recombinant FGF10 (100 ng/Al, R&D Systems) or PBS (buffer) were grafted onto foreguts after 48 h culture.

Techniques: Expressing, Immunostaining, Control, Labeling

Journal: Developmental biology

Article Title: Retinoic acid selectively regulates Fgf10 expression and maintains cell identity in the prospective lung field of the developing foregut.

doi: 10.1016/j.ydbio.2004.04.039

Figure Lengend Snippet: Fig. 8. Proposed model for the role of RA in early lung morphogenesis. Early in mouse foregut organogenesis, RA signaling is active in all layers. (A) By the 15-somite stage, RA has induced proliferation of a critical mass of mesodermal cells in the lung field, while signaling in endoderm maintains identity in lung progenitor cells (in red). (B) At around 25 somites, the condensing mesodermal cells begin to locally express Fgf10 (in green), which then activates the Fgf pathway in the endoderm to expand the population of lung progenitor cells into a primary endodermal bud. (C) Once secondary buds form and branching morphogenesis starts, RA signaling is downregulated in the lung and Fgf10 expression becomes independent of RA.

Article Snippet: In some experiments, heparin beads soaked in human recombinant FGF10 (100 ng/Al, R&D Systems) or PBS (buffer) were grafted onto foreguts after 48 h culture.

Techniques: Expressing