Wnt signalling in lung development and diseases (original) (raw)
Development, 2011
Bone morphogenetic protein 4 (Bmp4) is essential for lung development. To define the intracellular signaling mechanisms by which Bmp4 regulates lung development, BMP-specific Smad1 or Smad5 was selectively knocked out in fetal mouse lung epithelial cells. Abrogation of lung epithelial-specific Smad1, but not Smad5, resulted in retardation of lung branching morphogenesis and reduced sacculation, accompanied by altered distal lung epithelial cell proliferation and differentiation and, consequently, severe neonatal respiratory failure. By combining cDNA microarray with ChIP-chip analyses, Wnt inhibitory factor 1 (Wif1) was identified as a novel target gene of Smad1 in the developing mouse lung epithelial cells. Loss of Smad1 transcriptional activation of Wif1 was associated with reduced Wif1 expression and increased Wnt/β-catenin signaling activity in lung epithelia, resulting in specific fetal lung abnormalities. This suggests a novel regulatory loop of Bmp4-Smad1-Wif1-Wnt/β-catenin i...
Integrating regulatory mechanisms of Wnt signaling in development and tissue homeostasis
2017
Evolutionarily conserved signal transduction pathways mediate the ability of cells to respond to their environment and coordinate with each other for proper development and homeostasis of an organism. The Wnt/Wingless (Wg) pathway is required for proliferation, differentiation, stem-cell renewal and homeostasis, and when disrupted leads to disease. Wnt signaling does not control all these processes alone, its activity is extensively regulated by interaction with other signaling pathways and cellular mechanisms. This is mediated predominantly through phospho-regulation of the key pathway components by kinases and phosphatases. Our lab conducted an in vivo RNAi screen designed to identify novel kinase and phosphatase regulators of the Wnt pathway. In my PhD thesis research I further characterized three potential regulators: Downstream of Raf1 (Dsor1), Protein phosphatase 4 (PP4), and myosin phosphatase. Knockdown of Dsor1 reduced Wnt target gene expression and decreased stabilized βcatenin, the key effector protein of the Wnt pathway. Dsor1 and β-catenin had a close physical interaction, and catalytically inactive Dsor1 caused a reduction in active βcatenin, suggesting that Dsor1 counteracts destruction of β-catenin. Additionally, Ras-Dsor1 activity was independent of EGFR, and likely activated by the insulin-like receptor to promote Wnt. This work demonstrates novel crosstalk between Insulin and Wnt signaling via Dsor1. The reduction of PP4 inhibited Wg pathway activity, by reducing Notch-driven wg transcription. PP4 was found to promote Notch signaling within the nucleus of the receiving cell. Furthermore, PP4 regulates proliferation independently of its Notch interaction. This study identified a new role for PP4 in Notch signaling, and subsequently transcriptional regulation of wg. Reduced myosin phosphatase inhibited Wnt signaling by causing increased non-muscle myosin II (NMII) activation and cellular contraction. NMII activation stabilizes cortical F-actin resulting in accumulation of Ecadherin to the adherens junctions (AJ). E-cadherin titrates available β-catenin to the AJs in order to maintain cell-cell adhesion under contraction. The decreased cytoplasmic β-catenin results in insufficient nuclear translocation for full Wnt target gene transcription. This work elucidates that the dynamic activation of actomyosin contractility refines patterning of Wnt target gene expression. These studies identified three novel regulatory mechanisms for controlling Wnt signaling in development and homeostasis.
Scientific Reports, 2020
Lung malignancies comprise lethal and aggressive tumours that remain the leading cancer-related death cause worldwide. Regarding histological classification, lung squamous cell carcinoma (LUSC) and adenocarcinoma (LUAD) account for the majority of cases. Surgical resection and various combinations of chemo- and radiation therapies are the golden standards in the treatment of lung cancers, although the five-year survival rate remains very poor. Notch, Hedgehog, Wnt and Erbb signalling are evolutionarily conserved pathways regulating pivotal cellular processes such as differentiation, proliferation, and angiogenesis during embryogenesis and post-natal life. However, to date, there is no study comprehensively revealing signalling networks of these four pathways in LUSC and LUAD. Therefore, the aim of the present study was the investigation profiles of downstream target genes of pathways that differ between LUSC and LUAD biology. Our results showed a few co-expression modules, identifie...
A Role for Wnt Signaling Genes in the Pathogenesis of Impaired Lung Function in Asthma
American Journal of Respiratory and Critical Care Medicine, 2010
At-a-Glance Commentary: Scientific Knowledge on the Subject: The trajectory of lung function growth appears to be set early in life. Animal models demonstrate that abnormal in utero expression of genes implicated in normal lung development can result in abnormal pulmonary phenotypes after birth.
Frontiers in Cell and Developmental Biology, 2020
FGF signaling plays an essential role in lung development, homeostasis, and regeneration. We employed mouse 3D cell culture models and imaging to study ex vivo the role of FGF ligands and the interplay of FGF signaling with epithelial growth factor (EGF) and WNT signaling pathways in lung epithelial morphogenesis and differentiation. In non-adherent conditions, FGF signaling promoted formation of lungospheres from lung epithelial stem/progenitor cells (LSPCs). Ultrastructural and immunohistochemical analyses showed that LSPCs produced more differentiated lung cell progeny. In a 3D extracellular matrix, FGF2, FGF7, FGF9, and FGF10 promoted lung organoid formation. FGF9 showed reduced capacity to promote lung organoid formation, suggesting that FGF9 has a reduced ability to sustain LSPC survival and/or initial divisions. FGF7 and FGF10 produced bigger organoids and induced organoid branching with higher frequency than FGF2 or FGF9. Higher FGF concentration and/or the use of FGF2 with increased stability and affinity to FGF receptors both increased lung organoid and lungosphere formation efficiency, respectively, suggesting that the level of FGF signaling is a crucial driver of LSPC survival and differentiation, and also lung epithelial morphogenesis. EGF signaling played a supportive but non-essential role in FGF-induced lung organoid formation. Analysis of tissue architecture and cell type composition confirmed that the lung organoids contained alveolar-like regions with cells expressing alveolar type I and type II cell markers, as well as airway-like structures with club cells and ciliated cells. FGF ligands showed differences in promoting distinct lung epithelial cell types. FGF9 was a potent inducer of more proximal cell types, including ciliated and basal cells. FGF7 and FGF10 directed the differentiation toward distal lung lineages. WNT signaling enhanced the efficiency of lung organoid formation, but in the absence of FGF10 signaling, the organoids displayed limited branching and less differentiated phenotype. In summary, we present lung 3D cell culture models as useful tools to study the role and interplay of signaling pathways in postnatal lung development and homeostasis, and we reveal distinct roles for FGF ligands in regulation of mouse lung morphogenesis and differentiation ex vivo.
PLoS ONE, 2011
Canonical Wnt signaling plays multiple roles in lung organogenesis and repair by regulating early progenitor cell fates: investigation has been enhanced by canonical Wnt reporter mice, TOPGAL, BATGAL and Axin2 LacZ . Although widely used, it remains unclear whether these reporters convey the same information about canonical Wnt signaling. We therefore compared beta-galactosidase expression patterns in canonical Wnt signaling of these reporter mice in whole embryo versus isolated prenatal lungs. To determine if expression varied further during repair, we analyzed comparative pulmonary expression of beta-galactosidase after naphthalene injury. Our data show important differences between reporter mice. While TOPGAL and BATGAL lines demonstrate Wnt signaling well in early lung epithelium, BATGAL expression is markedly reduced in late embryonic and adult lungs. By contrast, Axin2 LacZ expression is sustained in embryonic lung mesenchyme as well as epithelium. Three days into repair after naphthalene, BATGAL expression is induced in bronchial epithelium as well as TOPGAL expression (already strongly expressed without injury). Axin2 LacZ expression is increased in bronchial epithelium of injured lungs. Interestingly, both TOPGAL and Axin2 LacZ are up regulated in parabronchial smooth muscle cells during repair. Therefore the optimal choice of Wnt reporter line depends on whether up-or down-regulation of canonical Wnt signal reporting in either lung epithelium or mesenchyme is being compared.
Journal of Clinical Investigation, 2011
Although mutations in Kras are present in 21% of lung tumors, there is a high level of heterogeneity in phenotype and outcome among patients with lung cancer bearing similar mutations, suggesting that other pathways are important. Wnt/β-catenin signaling is a known oncogenic pathway that plays a well-defined role in colon and skin cancer; however, its role in lung cancer is unclear. We have shown here that activation of Wnt/β-catenin in the bronchiolar epithelium of the adult mouse lung does not itself promote tumor development. However, concurrent activation of Wnt/β-catenin signaling and expression of a constitutively active Kras mutant (KrasG12D) led to a dramatic increase in both overall tumor number and size compared with KrasG12D alone. Activation of Wnt/β-catenin signaling altered the KrasG12D tumor phenotype, resulting in a phenotypic switch from bronchiolar epithelium to the highly proliferative distal progenitors found in the embryonic lung. This was associated with decreased E-cadherin expression at the cell surface, which may underlie the increased metastasis of tumors with active Wnt/β-catenin signaling. Together, these data suggest that activation of Wnt/β-catenin signaling can combine with other oncogenic pathways in lung epithelium to produce a more aggressive tumor phenotype by imposing an embryonic distal progenitor phenotype and by decreasing E-cadherin expression. Conflict of interest: The authors have declared that no conflict of interest exists.
CFTR and Wnt/beta-catenin signaling in lung development
BMC Developmental Biology, 2008
Background: Cystic fibrosis transmembrane conductance regulator (CFTR) was shown previously to modify stretch induced differentiation in the lung. The mechanism for CFTR modulation of lung development was examined by in utero gene transfer of either a sense or antisense construct to alter CFTR expression levels.