Analysis of Liver Progenitor Cells Generated from Yap Expression [Set 1]
ABSTRACT: Hippo signaling is highly associated with activity in the stem cell compartment of many epithelial tissues. In this study, we examined if Hippo signaling inhibition (by inducing Yap expression) could convert differentiated cells into a progenitor like phenotype. Organoid cells derived from mouse livers under various conditions, wild-type, Yap ON (Plus Dox), and Yap ON then OFF (Minus Dox) was examined. Comparison between freshly isolated hepatocytes; Uninduced_YPF-#.cel against Organoids grown in wild-type conditions (WT), Yap On (in vivo) off (in vitro) - YapOrganoidDoxMinus , and Yap On continuously - YapOrganoidDoxPlus. Organoids grown in culture or YFP+ sorted liver cells after the indicated time of Yap expression were collected. These were amplified using Nugene technology and hybridized to Affymetrix MoGene1.0 st arrays.
Project description:Hippo signaling is highly associated with activity in the stem cell compartment of many epithelial tissues. In this study, we examined if Hippo signaling inhibition (by inducing Yap expression) could convert differentiated cells into a progenitor like phenotype. Rosa26-lsl-YFP mice had recombination induced and cells were FACS sorted using YFP as a marker at either 1 week or 6 weeks after recombination. YFP expression is a surrogate for Yap expression (our protein of interest) and time was varied in vivo. RNA was immediately extracted after sorting and labeled to be hybridized to the array. FACS sorted Yap expressing liver cells were sorted one or six weeks after induction and compared to fetal liver samples as controls The control data from fetal liver samples have been previously published and is available in the GEO database as GSE12117 (GSM305568, GSM305569, GSM305570). The complete dataset representing: Yap Expressiong Liver samples and the fetal liver control Samples from Series GSE12117 (re-processed in this study), is linked below as a supplementary file.
Project description:Liver undergoes both size increase and differentiation during postnatal period, which in mice is approximately first 30 days. The mechanisms of simultaneous postnatal liver cell proliferation and maturation are not clear. In these experiments, role of yes associated protein (Yap), the downstream effector of Hippo Kinase signaling pathway was investigated. Total RNA isolated from livers of Yap+/+ and Yap+/- mice at Postnatal day 30. Pooled livers from 5 mice per genotype were used.
Project description:The Hippo pathway plays a crucial in organ size control during development and tissue homeostasis in adult life. To examine a role for Hippo signaling in the intestinal epithelium, we analyzed gene expression patterns in the mouse intestinal epithelilum transfected with siRNAs or expression plasmids for shRNAs targeting the Hippo pathway effectors, YAP and TAZ. We performed two independent series of experiments (siGFP (n=3) vs siYAP/siTAZ (n=3), and shLacZ (n=1) vs shYAP/shTAZ (n=1)). Control siRNA (siGFP), YAP/TAZ siRNAs, or expression plasmids for control shRNA (shLacZ) or YAP/TAZ shRNAs were introduced into the mouse intestinal epithelium by the newly-developed in vivo transfection method. Four days after transfection, intestinal epithelial cells were isolated from the tissues and total RNA was extracted.
Project description:Global downregulation of microRNAs (miRNAs) is commonly observed in human cancers and can have a causative role in tumorigenesis. The mechanisms responsible for this phenomenon remain poorly understood. Here we show that YAP, the downstream target of the tumor-suppressive Hippo signaling pathway regulates miRNA biogenesis in a cell density-dependent manner. At low cell density, nuclear YAP binds and sequesters p72 (DDX17), a regulatory component of the miRNA processing machinery. At high cell density, Hippo-mediated cytoplasmic retention of YAP facilitates p72 association with Microprocessor and binding to a specific sequence motif in pri-miRNAs. Inactivation of the Hippo pathway or expression of constitutively active YAP causes widespread miRNA suppression in cells and tumors and a corresponding post-transcriptional induction of MYC expression. Thus, the Hippo pathway links contact-inhibition regulation to miRNA biogenesis and may be responsible for the widespread miRNA repression observed in cancer. Two conditions (siCtrl and siYAP) were analyzed in duplicate.
Project description:Hippo effectors YAP/TAZ act as on-off mechanosensing switches by sensing modifications in extracellular matrix (ECM) composition and mechanics. The regulation of their activity has been described so far through a hierarchical model in which elements of Hippo pathway are under the control of Focal Adhesions (FAs). Here we unveiled the molecular mechanism by which cell spreading and RhoA GTPase control FA formation through YAP to stabilize the anchorage of actin cytoskeleton to cell membrane. This mechanism required YAP co-transcriptional function and involved the activation of genes encoding for integrins and FA docking proteins. Tuning YAP transcriptional activity led to the modification of cell mechanics, force development, adhesion strength, determined cell shaping, migration and differentiation. These results provide new insights into the mechanism of YAP mechanosensing activity and qualify Hippo effector as the key determinant of cell mechanics in response to ECM cues.
Project description:Background—YAP, the nuclear effector of Hippo signaling, regulates cellular growth and survival in multiple organs, including the heart, by interacting with TEAD sequence specific DNA-binding proteins. Recent studies showed that YAP stimulates cardiomyocyte proliferation and survival. However, the direct transcriptional targets through which YAP exerts its effects are poorly defined. Methods and Results—To identify genes directly regulated by YAP in cardiomyocytes, we combined differential gene expression analysis in YAP gain- and loss-of-function with genome-wide identification of YAP bound loci using chromatin immunoprecipitation and high throughput sequencing. This screen identified Pik3cb, encoding p110β, a catalytic subunit of phosphoinositol-3-kinase (PI3K), as a candidate YAP effector that promotes cardiomyocyte proliferation and survival. We validated YAP and TEAD occupancy of a conserved enhancer within the first intron of Pik3cb, and show that this enhancer drives YAP-dependent reporter gene expression. Yap gain- and loss-of-function studies indicated that YAP is necessary and sufficient to activate the PI3K-Akt pathway. Like Yap, Pik3cb gain-of-function stimulated cardiomyocyte proliferation, and Pik3cb knockdown dampened the YAP mitogenic activity. Reciprocally, Yap loss-of-function impaired heart function and reduced cardiomyocyte proliferation and survival, all of which were significantly rescued by AAV-mediated Pik3cb expression. Conclusion—Pik3cb is a crucial direct target of YAP, through which the YAP activates PI3K-AKT pathway and regulates cardiomyocyte proliferation and survival. Two groups were involved in this study:TNTcreYapfl_het group and TNTcreYapfl_KO group. Each group contained three biological replicates. Embryo hearts were collected at E12.5 and dissociated. Cardiomyocytes were collected by FACS. The total RNA of cardiomyocytes were isolated for microarray analysis.
Project description:Hippo signalling has been implicated as a key regulator of tissue regeneration. In the intestine, ex vivo organoid cultures model aspects of crypt epithelial regeneration. Therefore in order to uncover the Yap regulated transcriptional programs during crypt regeneration we performed RNA-sequencing of Yap wt and Yap deficient organoids, as well as organoids inducibly expressing Yap. Overall design: Yap loss of function organoids were harvested from Yapfl/fl;VillinCre mice (Yap-/-). In addition, we developed Yap overexpressing organoids by generating a doxycycline-inducible wild-type Yap transgenic line under the control of a Cre driven reverse tetracycline transactivator (rtTA), referred to here as YapTg. Organoids were seeded on day 0 from whole crypts isolated from Yap+/D, YapD/D, YapTg mice and cultured for 24 hours at which time they were harvested for transcriptome analysis by RNAseq.
Project description:YAP is the principle effector of the Hippo signaling pathway; a key regulator of tissue homeostasis whose dysregulation is linked to cancer development. YAP regulation of gene expression is thought to involve the TEAD transcription factor family. Here we show that YAP and TEAD1 binding always co-occurs and is mediated by single as well as double TEAD1 motifs with a particular 3bp spacer (CATTCCNNNCATTCC). This suggests that YAP activity appears exclusively mediated by TEAD1. Despite being characterized as a promoter-binding factor YAP/TEAD actually binds predominantly to enhancers. Moreover we show that YAP is necessary for activity of the linked gene and proper chromatin state of regulated enhancers. These results establish mode of binding and activation of YAP mediated nuclear response of the Hippo pathway by TEAD1 and provide a comprehensive list and a novel class of direct target genes that are regulated distally and could be exploited for cancer therapeutics. Sequencing of ChIP and input samples for YAP1 and TEAD1 transcription factors and H3K27ac histone modification in SF268 glioblastoma cells and for YAP1 transcription factor in NCI-H2052 mesothelioma cells.
Project description:Mammary organoids harvested from ErbB3 DOX-KO mice, which utilize MMTV-Cre transgene expression in the LE to cause genomic recombination at floxed ErbB3 alleles in ErbB3FL/FL were cultured in the presence or absence of doxycycline to induce ErbB3 loss. The gene expression shift following DOX-induced ErbB3 loss in the 3D organoids was examined by microarray. Gene expression patterns were interrogated in mammary organoids from ErbB3 inducible-knockout mice cultured in the presence of absence of doxycycline. Three biological replicates of the experiment were performed, resulting in a total of 6 samples (3 treatment, 3 control).