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Formation and differentiation of multiple mesenchymal lineages during lung development is regulated by beta-catenin signaling.

De Langhe SP, Carraro G, Tefft D, Li C, Xu X, Chai Y, Minoo P, Hajihosseini MK, Drouin J, Kaartinen V, Bellusci S - PLoS ONE (2008)

Bottom Line: The amplification but not differentiation of Fgf10-expressing parabronchial smooth muscle progenitor cells is drastically reduced.In the angioblast-endothelial lineage, however, only differentiation into mature endothelial cells is impaired.Taken together these findings reveal a hierarchy of gene activity involving ss-catenin and PITX, as important regulators of mesenchymal cell proliferation and differentiation.

View Article: PubMed Central - PubMed

Affiliation: Developmental Biology Program, Department of Surgery, Saban Research Institute of Childrens Hospital Los Angeles, Los Angeles, California, USA.

ABSTRACT

Background: The role of ss-catenin signaling in mesodermal lineage formation and differentiation has been elusive.

Methodology: To define the role of ss-catenin signaling in these processes, we used a Dermo1(Twist2)(Cre/+) line to target a floxed beta-catenin allele, throughout the embryonic mesenchyme. Strikingly, the Dermo1(Cre/+); beta-catenin(f/-) conditional Knock Out embryos largely phenocopy Pitx1(-/-)/Pitx2(-/-) double knockout embryos, suggesting that ss-catenin signaling in the mesenchyme depends mostly on the PITX family of transcription factors. We have dissected this relationship further in the developing lungs and find that mesenchymal deletion of beta-catenin differentially affects two major mesenchymal lineages. The amplification but not differentiation of Fgf10-expressing parabronchial smooth muscle progenitor cells is drastically reduced. In the angioblast-endothelial lineage, however, only differentiation into mature endothelial cells is impaired.

Conclusion: Taken together these findings reveal a hierarchy of gene activity involving ss-catenin and PITX, as important regulators of mesenchymal cell proliferation and differentiation.

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Related in: MedlinePlus

Reduced c-Myc expression and lack of PSMC progenitor amplification in CKO lungs.(a-b) Section RISH for c-Myc on E14.5 WT and CKO lungs. Expression of c-Myc is lost in CKO lung mesenchyme were β-catenin is completely deleted but remains the same were β-catenin expression is unaltered. These sections are adjacent to the ones represented in Fig. 1k,l illustrating mosaic β-catenin deletion. (c-d) Immunofluorescence for β-catenin (green) and α-SMA (red) on sections through E13.5 WT and CKO lungs. Absence of β-catenin in CKO lung mesenchyme and patchy α-SMA expression around the bronchi (d) and high magnification inset in (d). (e–f) Untreated primary cultures of mesenchyme from both WT and CKO lungs spontaneously differentiate into smooth muscle cells in vitro. (g–h) Primary cultures from WT lungs treated with FGF9 fail to differentiate into smooth muscle cells (g) while primary cultures from CKO lungs (h) are not affected in their differentiation after FGF9 treatment. (i–l) Immunofluorescence for β-catenin (green) and P-ERK (red) on primary culture of WT and CKO lung mesenchyme treated or not with FGF9. Upon FGF9 treatment, Note the drastic increase in P-ERK expression in WT cells in comparison to CKO cells.
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pone-0001516-g005: Reduced c-Myc expression and lack of PSMC progenitor amplification in CKO lungs.(a-b) Section RISH for c-Myc on E14.5 WT and CKO lungs. Expression of c-Myc is lost in CKO lung mesenchyme were β-catenin is completely deleted but remains the same were β-catenin expression is unaltered. These sections are adjacent to the ones represented in Fig. 1k,l illustrating mosaic β-catenin deletion. (c-d) Immunofluorescence for β-catenin (green) and α-SMA (red) on sections through E13.5 WT and CKO lungs. Absence of β-catenin in CKO lung mesenchyme and patchy α-SMA expression around the bronchi (d) and high magnification inset in (d). (e–f) Untreated primary cultures of mesenchyme from both WT and CKO lungs spontaneously differentiate into smooth muscle cells in vitro. (g–h) Primary cultures from WT lungs treated with FGF9 fail to differentiate into smooth muscle cells (g) while primary cultures from CKO lungs (h) are not affected in their differentiation after FGF9 treatment. (i–l) Immunofluorescence for β-catenin (green) and P-ERK (red) on primary culture of WT and CKO lung mesenchyme treated or not with FGF9. Upon FGF9 treatment, Note the drastic increase in P-ERK expression in WT cells in comparison to CKO cells.

Mentions: The loss of proliferation noted in CKO lungs led us to measure the levels of c-Myc expression, which is known to be a ß-catenin/PITX2 signaling target gene [17] and key regulator of cell proliferation [36]. As shown in Fig. 5a, c-Myc is normally expressed in the mesenchyme but its expression levels are drastically reduced both in CKO lungs (Fig. 5a,b) and in Pitx2−/− lungs (supplemental Fig. S2). c-Myc expression was maintained in the regions where β-catenin was not deleted (Fig. 1l), serving therefore as an internal control and indicating further that these effects are cell autonomous. Together with the proliferation data presented earlier (Fig. 4c,d), these results support the conclusion that ß-catenin signaling drives the proliferation of Fgf10-expressing sub-mesothelial cells.


Formation and differentiation of multiple mesenchymal lineages during lung development is regulated by beta-catenin signaling.

De Langhe SP, Carraro G, Tefft D, Li C, Xu X, Chai Y, Minoo P, Hajihosseini MK, Drouin J, Kaartinen V, Bellusci S - PLoS ONE (2008)

Reduced c-Myc expression and lack of PSMC progenitor amplification in CKO lungs.(a-b) Section RISH for c-Myc on E14.5 WT and CKO lungs. Expression of c-Myc is lost in CKO lung mesenchyme were β-catenin is completely deleted but remains the same were β-catenin expression is unaltered. These sections are adjacent to the ones represented in Fig. 1k,l illustrating mosaic β-catenin deletion. (c-d) Immunofluorescence for β-catenin (green) and α-SMA (red) on sections through E13.5 WT and CKO lungs. Absence of β-catenin in CKO lung mesenchyme and patchy α-SMA expression around the bronchi (d) and high magnification inset in (d). (e–f) Untreated primary cultures of mesenchyme from both WT and CKO lungs spontaneously differentiate into smooth muscle cells in vitro. (g–h) Primary cultures from WT lungs treated with FGF9 fail to differentiate into smooth muscle cells (g) while primary cultures from CKO lungs (h) are not affected in their differentiation after FGF9 treatment. (i–l) Immunofluorescence for β-catenin (green) and P-ERK (red) on primary culture of WT and CKO lung mesenchyme treated or not with FGF9. Upon FGF9 treatment, Note the drastic increase in P-ERK expression in WT cells in comparison to CKO cells.
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Related In: Results  -  Collection

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pone-0001516-g005: Reduced c-Myc expression and lack of PSMC progenitor amplification in CKO lungs.(a-b) Section RISH for c-Myc on E14.5 WT and CKO lungs. Expression of c-Myc is lost in CKO lung mesenchyme were β-catenin is completely deleted but remains the same were β-catenin expression is unaltered. These sections are adjacent to the ones represented in Fig. 1k,l illustrating mosaic β-catenin deletion. (c-d) Immunofluorescence for β-catenin (green) and α-SMA (red) on sections through E13.5 WT and CKO lungs. Absence of β-catenin in CKO lung mesenchyme and patchy α-SMA expression around the bronchi (d) and high magnification inset in (d). (e–f) Untreated primary cultures of mesenchyme from both WT and CKO lungs spontaneously differentiate into smooth muscle cells in vitro. (g–h) Primary cultures from WT lungs treated with FGF9 fail to differentiate into smooth muscle cells (g) while primary cultures from CKO lungs (h) are not affected in their differentiation after FGF9 treatment. (i–l) Immunofluorescence for β-catenin (green) and P-ERK (red) on primary culture of WT and CKO lung mesenchyme treated or not with FGF9. Upon FGF9 treatment, Note the drastic increase in P-ERK expression in WT cells in comparison to CKO cells.
Mentions: The loss of proliferation noted in CKO lungs led us to measure the levels of c-Myc expression, which is known to be a ß-catenin/PITX2 signaling target gene [17] and key regulator of cell proliferation [36]. As shown in Fig. 5a, c-Myc is normally expressed in the mesenchyme but its expression levels are drastically reduced both in CKO lungs (Fig. 5a,b) and in Pitx2−/− lungs (supplemental Fig. S2). c-Myc expression was maintained in the regions where β-catenin was not deleted (Fig. 1l), serving therefore as an internal control and indicating further that these effects are cell autonomous. Together with the proliferation data presented earlier (Fig. 4c,d), these results support the conclusion that ß-catenin signaling drives the proliferation of Fgf10-expressing sub-mesothelial cells.

Bottom Line: The amplification but not differentiation of Fgf10-expressing parabronchial smooth muscle progenitor cells is drastically reduced.In the angioblast-endothelial lineage, however, only differentiation into mature endothelial cells is impaired.Taken together these findings reveal a hierarchy of gene activity involving ss-catenin and PITX, as important regulators of mesenchymal cell proliferation and differentiation.

View Article: PubMed Central - PubMed

Affiliation: Developmental Biology Program, Department of Surgery, Saban Research Institute of Childrens Hospital Los Angeles, Los Angeles, California, USA.

ABSTRACT

Background: The role of ss-catenin signaling in mesodermal lineage formation and differentiation has been elusive.

Methodology: To define the role of ss-catenin signaling in these processes, we used a Dermo1(Twist2)(Cre/+) line to target a floxed beta-catenin allele, throughout the embryonic mesenchyme. Strikingly, the Dermo1(Cre/+); beta-catenin(f/-) conditional Knock Out embryos largely phenocopy Pitx1(-/-)/Pitx2(-/-) double knockout embryos, suggesting that ss-catenin signaling in the mesenchyme depends mostly on the PITX family of transcription factors. We have dissected this relationship further in the developing lungs and find that mesenchymal deletion of beta-catenin differentially affects two major mesenchymal lineages. The amplification but not differentiation of Fgf10-expressing parabronchial smooth muscle progenitor cells is drastically reduced. In the angioblast-endothelial lineage, however, only differentiation into mature endothelial cells is impaired.

Conclusion: Taken together these findings reveal a hierarchy of gene activity involving ss-catenin and PITX, as important regulators of mesenchymal cell proliferation and differentiation.

Show MeSH
Related in: MedlinePlus