VANGL2 regulates luminal epithelial organization and cell turnover in the mammary gland.
ABSTRACT: The VANGL family of planar cell polarity proteins is implicated in breast cancer however its function in mammary gland biology is unknown. Here, we utilized a panel of Vang1 and Vangl2 mouse alleles to examine the requirement of VANGL family members in the murine mammary gland. We show that Vang1CKO?/? glands display normal branching while Vangl2flox/flox and Vangl2Lp/Lp tissue exhibit several phenotypes. In MMTV-Cre;Vangl2flox/flox glands, cell turnover is reduced and lumens are narrowed. A Vangl2 missense mutation in the Vangl2Lp/Lp tissue leads to mammary anlage sprouting defects and deficient outgrowth with transplantation of anlage or secondary tissue fragments. In successful Vangl2Lp/Lp outgrowths, three morphological phenotypes are observed: distended ducts, supernumerary end buds, and ectopic acini. Layer specific defects are observed with loss of Vangl2 selectively in either basal or luminal layers of mammary cysts. Loss in the basal compartment inhibits cyst formation, but has the opposite effect in the luminal compartment. Candidate gene analysis on MMTV-Cre;Vangl2flox/flox and Vangl2Lp/Lp tissue reveals a significant reduction in Bmi1 expression, with overexpression of Bmi1 rescuing defects in Vangl2 knockdown cysts. Our results demonstrate that VANGL2 is necessary for normal mammary gland development and indicate differential functional requirements in basal versus luminal mammary compartments.
Project description:The planar cell polarity (PCP) pathway, incorporating non-canonical Wnt signalling, controls embryonic convergent (CE) extension, polarized cell division and ciliary orientation. It also limits diameters of differentiating renal tubules, with mutation of certain components of the pathway causing cystic kidneys. Mutations in mouse Vangl genes encoding core PCP proteins cause neural tube defects (NTDs) and Vangl2 mutations also impair branching of embryonic mouse lung airways. Embryonic metanephric kidneys also undergo branching morphogenesis and Vangl2 is known to be expressed in ureteric bud/collecting duct and metanephric mesenchymal/nephron lineages. These observations led us to investigate metanephroi in Vangl2 mutant mice, Loop-tail (Lp). Although ureteric bud formation is normal in Vangl2(Lp/Lp) embryos, subsequent in vivo and in vitro branching morphogenesis is impaired. Null mutant kidneys are short, consistent with a CE defect. Differentiating glomerular epithelia express several PCP genes (Vangl1/2, Celsr1, Scrib, Mpk1/2 and Fat4) and glomeruli in Vangl2(Lp/Lp) fetuses are smaller and contain less prominent capillary loops than wild-type littermates. Furthermore, Vangl2(Lp/+) kidneys had modest reduction in glomerular numbers postnatally. Vangl2(Lp/Lp) metanephroi contained occasional dilated tubules but no overt cystic phenotype. These data show for the first time that a PCP gene is required for normal morphogenesis of both the ureteric bud and metanephric mesenchyme-derived structures. It has long been recognized that certain individuals with NTDs are born with malformed kidneys, and recent studies have discovered VANGL mutations in some NTD patients. On the basis of our mutant mouse study, we suggest that PCP pathway mutations should be sought when NTD and renal malformation co-exist.
Project description:We have identified GATA-3 as a critical regulator of luminal cell differentiation in the mammary gland. Acute loss of GATA-3 in the adult mammary gland leads to an expansion of an undifferentiated luminal epithelium and the formation of a multi-layered epithelium. Here we report microarray analysis of mammary glands that have undergone acute loss of GATA-3 Adult GATA-3flox/flox; WAP-rtTA-Cre and GATA-flox/+; WAP-rtTA-Cre mice were administered doxyxcline for 5 days and their mammary glands harvested. Total RNA was extracted by the Trizol method. Het mammary gland total RNA was labeled with Cy5 while Null mammary gland total RNA was labeled with Cy3. Microarray hybridization was performed on spotted oligonucleotide microarrays with 38,000 features. Lowess print-tip normalization and analysis was performed on the Acuity software package (V 4.0)
Project description:Skin-mammary specific knockout (SSKO) of Pygo2 (K14-cre; Pygo2 flox/-) , a WNT signaling co-activator, results in defective mouse mammary gland development. The FACS sorted mammary stem cell (MaSC)/basal population from Pygo2 SSKO mammary gland displays biased differentiation towards luminal/alveolar lineage in vitro, and reduced regeneration rate of new mammary gland in vivo To gain the insight into gene expression profiles in control and Pygo2 SSKO mammary epithelial cells (MECs), we sorted the freshly isolated mouse MECs into MaSC/basal (Lin-CD29hiCD24+) and mature luminal population (Lin-CD29lowCD24+CD61-), and extract total RNA for cDNA microarray analysis
Project description:Integrin-extracellular matrix interactions play important roles in the coordinated integration of external and internal cues that are essential for proper development. To study the role of beta1 integrin in the mammary gland, Itgbeta1(flox/flox) mice were crossed with WAPiCre transgenic mice, which led to specific ablation of beta1 integrin in luminal alveolar epithelial cells. In the beta1 integrin mutant mammary gland, individual alveoli were disorganized resulting from alterations in cell-basement membrane associations. Activity of focal adhesion kinase (FAK) was also decreased in mutant mammary glands. Luminal cell proliferation was strongly inhibited in beta1 integrin mutant glands, which correlated with a specific increase of p21 Cip1 expression. In a p21 Cip1 null background, there was a partial rescue of BrdU incorporation, providing in vivo evidence linking p21 Cip1 to the proliferative defect observed in beta1 integrin mutant glands. A connection between p21 Cip1 and beta1 integrin as well as FAK was also established in primary mammary cells. These results point to the essential role of beta1 integrin signaling in mammary epithelial cell proliferation.
Project description:<h4>Background</h4>Mutations in the Planar Cell Polarity (PCP) core gene Vangl2 cause the most severe neural tube defects (NTD) in mice and humans. Genetic studies show that the Vangl2 gene genetically interacts with a close homologue Vangl1. How precisely Vangl2 and Vangl1 proteins interact and crosstalk has remained a difficult issue to address, with the main obstacle being the accurate discrimination of the two proteins, which share close sequence homology. Experimental evidence previously presented has been sparse and addressed with ectopically expressed proteins or with antibodies unable to biochemically discriminate Vangl1 from Vangl2, therefore giving rise to unclear results.<h4>Methodology and main findings</h4>A highly specific monoclonal anti-Vangl2 antibody was generated and rigorously tested on both recombinant and extracted Vangl2 using surface plasmon resonance (SPR) analysis, western blot, and immunoprecipitation experiments. This antibody efficiently affinity-purified Vangl2 from cell lysates and allowed the unambiguous identification of endogenous Vangl2 by proteomic analysis. Vangl1 was also present in Vangl2 immunoprecipitates, establishing the first biochemical evidence for the existence of Vangl2/Vangl1 heterodimers at an endogenous level. Epitope-tagged Vangl2 and Vangl1 confirmed that both proteins interact and colocalize at the plasma membrane. The Vangl2 antibody is able to acutely assess differential expression levels of Vangl2 protein in culture cell lines, as corroborated with gene expression analysis. We characterised Vangl2 expression in the cochlea of homozygous and heterozygous Lp mutant mice bearing a point mutation within the C-terminal Vangl2 region that leads to profound PCP defects. Our antibody could detect much lower levels of Vangl2(Lp) protein in mutant mice compared to the wild type mice.<h4>Conclusion</h4>Our results provide an in-depth biochemical characterisation of the interaction observed between Vangl paralogues.
Project description:Neural tube defects (NTDs) are very frequent congenital abnormalities in humans. Recently, we have documented independent association of Vangl1 and Vangl2 gene mutations with NTDs. In the Looptail mouse, homozygosity (but not heterozygosity) for loss-of-function alleles at Vangl2 causes the severe NTD craniorachischisis, whereas heterozygosity for mutant variants of VANGL1 is associated with NTDs in a human cohort of sporadic and familial cases. To understand the role of Vangl1 in normal development, we created a mouse mutant with an inactivating mutation at Vangl1 (Vangl1(gt)). Vangl1 shows a dynamic pattern of expression in the developing neural tube and notochord at the time of neural tube closure. Vangl1(gt/+) heterozygotes and Vangl1(gt/gt) homozygotes are viable and fertile, although Vangl1(gt/gt) display subtle alterations in polarity of inner hair cells of the cochlea. Remarkably, and as opposed to healthy Vangl1(gt/+) and Vangl2(lp/+) heterozygotes, Vangl1(gt/+);Vangl2(lp/+) double heterozygotes show profound developmental defects that include severe craniorachischisis, inner ear defects (disorganization of the stereociliary bundles of hair cells of the organ of Corti), and cardiac abnormality (aberrant right subclavian artery). These results show that genetic interaction between Vangl1 and Vangl2 genes causes neural tube defects and raise the possibility that interaction between individual Vangl genes and other genetic loci and/or environmental factors may additionally contribute to the etiology of NTDs.
Project description:The purpose of this microarray experiment was to obtain reference gene expression patterns of a number of epithelial cell populations [mammary stem cells (MASC), luminal progenitors (LP), alveolar luminal stem/progenitor cells (WC virgin-these are mammary epithelial cells genetically marked by Wap-Cre in virgin females), mature luminal cells (ML, mainly represent ductal luminal cells in virgin females), and alveolar luminal cells (WC preg M-bM-^@M-^S these are alveolar cells genetically marked by Wap-Cre during mid-gestation)] present in the mammary gland of wildtype adult mice on a C57BL6 genetic background. For the isolation of RNA from mammary stem cells (MASC, Lin-CD24+CD29hi), luminal progenitors (LP, Lin-CD24hiCD29+CD61+), and mature luminal cells (ML, lin-CD24hiCD29+CD61-), the thoracic and inguinal mammary glands from 3 adult virgin female mice were harvested, minced and digested into a single cell suspension. Form each of these 3 single cell suspensions, the above populations were sorted by FACS. For alveolar luminal stem/progenitor cells and alveolar luminal cells, Lin-YFP+ mammary epithelial cells were isolated from virgin or midgestation mice genetically marked by Wap-Cre;R26Y. R26Y is a conditional YFP reporter that would be turned on upon Cre-mediated recombination.
Project description:Lung diseases impose a huge economic and health burden worldwide. A key aspect of several adult lung diseases, such as idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD), including emphysema, is aberrant tissue repair, which leads to an accumulation of damage and impaired respiratory function. Currently, there are few effective treatments available for these diseases and their incidence is rising. The planar cell polarity (PCP) pathway is critical for the embryonic development of many organs, including kidney and lung. We have previously shown that perturbation of the PCP pathway impairs tissue morphogenesis, which disrupts the number and shape of epithelial tubes formed within these organs during embryogenesis. However, very little is known about the role of the PCP pathway beyond birth, partly because of the perinatal lethality of many PCP mouse mutant lines. Here, we investigate heterozygous Looptail (Lp) mice, in which a single copy of the core PCP gene, Vangl2, is disrupted. We show that these mice are viable but display severe airspace enlargement and impaired adult lung function. Underlying these defects, we find that Vangl2Lp/+ lungs exhibit altered distribution of actin microfilaments and abnormal regulation of the actin-modifying protein cofilin. In addition, we show that Vangl2Lp/+ lungs exhibit many of the hallmarks of tissue damage, including an altered macrophage population, abnormal elastin deposition and elevated levels of the elastin-modifying enzyme, Mmp12, all of which are observed in emphysema. In vitro, disruption of VANGL2 impairs directed cell migration and reduces the rate of repair following scratch wounding of human alveolar epithelial cells. Moreover, using population data from a birth cohort of young adults, all aged 31, we found evidence of an interactive effect between VANGL2 and smoking on lung function. Finally, we show that PCP genes VANGL2 and SCRIB are significantly downregulated in lung tissue from patients with emphysema. Our data reveal an important novel role for the PCP pathway in adult lung homeostasis and repair and shed new light on the genetic factors which may modify destructive lung diseases such as emphysema.
Project description:Planar cell polarity (PCP) is an evolutionarily conserved essential mechanism that provides directional information to control and coordinate polarized cellular and tissue behavior during embryonic development. Disruption of PCP leads to severe morphological defects in vertebrates and its dysregulation results in a variety of human diseases such as neural tube defects and skeletal dysplasia. PCP is governed by a set of highly conserved core proteins that are asymmetrically localized at the cell surface throughout the polarized tissues. The uniform directionality of PCP is established by global cues, such as Wg/Wnt signaling gradients that break the original symmetrical localization of core PCP proteins including Vang/Vangl and Fz/Fzd. However, the exact mechanism remains elusive. In this study, we found that Vangl2 phosphorylation, which was previously identified to be induced by Wnt5a signaling, is required for Vangl2 functions in mammalian PCP in multiple tissues. The in vivo activities of Vangl2 are determined by its phosphorylation level. Phospho-mutant Vangl2 exhibits dominant negative effects, whereas Vangl2 with reduced phosphorylation is hypomorphic. We show that Vangl2 phosphorylation is essential for its uniform polarization pattern. Moreover, serine/threonine kinases CK1? and CK1? are redundantly required for Wnt5a-induced Vangl2 phosphorylation. Dvl family members are also required for Wnt5a-induced Vangl2 phosphorylation by enhancing the interaction of CK1 and Vangl2. These findings demonstrate that induction of Vangl protein phosphorylation plays an essential role in transducing Wnt5a signaling to establish PCP in mammalian development, suggesting a phosphorylation-regulated "Vangl activity gradient" model in addition to the well-documented "Fz activity gradient" model in Wnt/PCP signaling.
Project description:RNA from MMTV-Cre;Sox9flox/flox mouse mammary glands were compared to RNA from MMTV-Cre;Sox9+/flox glands. Results indicate that Sox9 regulates several genes that impact ductal morphogenesis in the mammary gland. The portion of the fourth mammary gland that is proximal to the intra-mammary gland lymph nodes was dissected from four 5-week-old MMTV-Cre;Sox9flox/flox females and four MMTV-Cre;Sox9+/flox females of the same age. Total RNA from each gland was extracted and hybridized to separate Affymetrix Gene 1.0 ST chips.