Project description:VEGF is a major driver of blood vessel formation. However, the signal transduction pathways culminating into the biological consequences of VEGF signaling are partially understood. Here we show that the Hippo pathway effectors YAP and TAZ, work as a regulatory hub in mediating VEGF-VEGFR2 signaling during angiogenesis. We demonstrate that YAP/TAZ are essential for vascular development as endothelium specific deletion of YAP/TAZ leads to impaired vascularization and embryonic lethality. Mechanistically, we show that VEGF activates YAP/TAZ via its effects on actin cytoskeleton remodeling, and that activated YAP/TAZ induce a transcriptional program that results in the expression of a set of genes to further control cytoskeleton dynamics, and thus ensure a proper angiogenic response. YAP/TAZ deletion also results in VEGFR2 trafficking defects from the Golgi to the plasma membrane. Together, our study establishes YAP/TAZ as a central regulatory hub that mediates VEGF signaling, and hence, regulates angiogenesis.
Project description:VEGF is a major driver of blood vessel formation. However, the signal transduction pathways culminating into the biological consequences of VEGF signaling are partially understood. Here we show that the Hippo pathway effectors YAP and TAZ, work as a regulatory hub in mediating VEGF-VEGFR2 signaling during angiogenesis. We demonstrate that YAP/TAZ are essential for vascular development as endothelium specific deletion of YAP/TAZ leads to impaired vascularization and embryonic lethality. Mechanistically, we show that VEGF activates YAP/TAZ via its effects on actin cytoskeleton remodeling, and that activated YAP/TAZ induce a transcriptional program that results in the expression of a set of genes to further control cytoskeleton dynamics, and thus ensure a proper angiogenic response. YAP/TAZ deletion also results in VEGFR2 trafficking defects from the Golgi to the plasma membrane. Together, our study establishes YAP/TAZ as a central regulatory hub that mediates VEGF signaling, and hence, regulates angiogenesis.
Project description:Uncontrolled Transforming growth factor-beta (TGFβ) signaling promotes aggressive metastatic properties in late-stage breast cancers. However, how TGFβ-mediated cues are directed to induce late-stage tumorigenic events is poorly understood, particularly given that TGFβ has clear tumor suppressing activity in other contexts. Here we demonstrate that the transcriptional regulators TAZ and YAP (TAZ/YAP), key effectors of the Hippo pathway, are necessary to promote and maintain TGFβ-induced tumorigenic phenotypes in breast cancer cells. Interactions between TAZ/YAP, TGFβ-activated SMAD2/3, and TEAD transcription factors reveal convergent roles for these factors in the nucleus. Genome-wide expression analyses indicate that TAZ/YAP, TEADs and TGFβ-induced signals coordinate a specific pro-tumorigenic transcriptional program. Importantly, genes cooperatively regulated by TAZ/YAP, TEAD, and TGFβ, such as the novel targets NEGR1 and UCA1, are necessary for maintaining tumorigenic activity in metastatic breast cancer cells. Nuclear TAZ/YAP also cooperate with TGFβ signaling to promote phenotypic and transcriptional changes in non-tumorigenic cells to overcome TGFβ repressive effects. Our work thus identifies crosstalk between nuclear TAZ/YAP and TGFβ signaling in breast cancer cells, revealing novel insight into late-stage disease-driving mechanisms. Expression profiling was conducted following the repression of the transcriptional regulators TAZ and YAP (TAZ/YAP), the TEAD family of transcription factors (TEAD1/2/3/4), or the TGFb signaling pathway (with SB-431542, an inhibitor of the TBRI recpeptor) in human MDA-MB-231-LM2 breast cancer cells treated with TGFβ1. Human MDA-MB-231-LM2-4 breast cancer cells were transfected with control siRNA, or siRNAs targeting TAZ/YAP or all four TEADs and were treated 24 hours later with 500pM TGFβ1 or 5mM SB-431542 for an additional 24 hours. Total RNA was isolated and twelve microarrays in total were performed, with each condition carried out three times on separate days. The Boston University Microarray Core generated the data using the Affymetrix Human Gene 1.0 St Array.
Project description:Angiogenesis, the process by which endothelial cells (ECs) form new blood vessels from existing ones, is intimately linked to the tissue's metabolic milieu and often occurs at nutrient-deficient sites. However, ECs rely on sufficient metabolic resources to support growth and proliferation. How endothelial nutrient acquisition and usage are regulated is unknown. Here we show that these processes are dictated by YAP/TAZ-TEAD – a transcriptional module whose function is highly responsive to changes in the tissue environment. ECs lacking YAP/TAZ or their transcriptional partners, TEAD1, 2, and 4 fail to divide, resulting in stunted vascular growth in mice. Conversely, activation of TAZ, the more abundant paralogue in ECs, boosts proliferation, leading to vascular hyperplasia. We find that YAP/TAZ promote angiogenesis by fueling nutrient mTORC1 signaling. By orchestrating the transcription of a repertoire of cell-surface transporters, YAP/TAZ-TEAD stimulate the import of amino acids and other essential nutrients, thereby enabling mTORC1 pathway activation. Dissociating mTORC1 from these nutrient inputs – elicited by the loss of Rag GTPases – inhibits mTORC1 activity and prevents YAP/TAZ-dependent vascular growth. These findings define a pivotal role for YAP/TAZ-TEAD in steering endothelial mTORC1 and illustrate the essentiality of coordinated nutrient fluxes in the vasculature.
Project description:The goal of this study was to identify YAP/TAZ direct transcriptional targets and transcriptional partners, through ChIP-sequencing and gene expression profiling. ChIP-seq analysis of YAP, TAZ, TEAD4 and JUN in MDA-MB-231 cells. Two independent replicates were analysed for each TF, as well as for negative controls.
Project description:Phosphodiesterase type 5 inhibitors (PDE5is) are the primary therapeutic option for erectile dysfunction. However, 30% of patients do not respond to PDE5is treatment, making the quest for a new treatment modality a central endeavor. Here, we found a new pathway in erectile function control, mechano-regulated YAP/TAZ activate Adrenomedullin transcription, which sustains smooth muscle cells (SMCs) relaxation to maintain the erection. We first found that penile erection stretches the SMCs, dominating YAP/TAZ activity. Subsequently, we showed that YAP/TAZ plays a vital role in erectile function and penile rehabilitation using genetic lesions and several animal models. The mechanism relies on the regulation of Adrenomedullin on penile SMCs contraction, which we identify here as a direct YAP/TAZ transcript. Notably, conventional PDE5is targeting NO-cGMP signaling do not cure YAP/TAZ deficient ED. In contrast, by activating YAP/TAZ-Adrenomedullin cascade, mechano-stimulation improved erectile function, including PDE5is non-responders in both experimental models and clinical trials. Our studies lay the groundwork for exploring mechano-YAP/TAZ-Adrenomedullin as prospective targets in the treatment of ED
Project description:The optic vesicle comprises a pool of bi-potential progenitor cells from which the retinal pigment epithelium (RPE) and neural retina fates segregate during ocular morphogenesis. Several transcription factors and signaling pathways have been shown to be important for RPE maintenance and differentiation, but an understanding of the initial fate specification and determination of this ocular cell type is lacking. We show that Yap/Taz-Tead activity is necessary and sufficient for optic vesicle progenitors to adopt RPE identity in zebrafish. A Teadresponsive transgene is expressed within the domain of the optic cup from which RPE arises, and Yap immunoreactivity localizes to the nuclei of prospective RPE cells. yap (yap1) mutants lack a subset of RPE cells and/or exhibit coloboma. Loss of RPE in yap mutants is exacerbated in combination with taz (wwtr1) mutant alleles such that, when Yap and Taz are both absent, optic vesicle progenitor cells completely lose their ability to form RPE. The mechanism of Yap dependent RPE cell type determination is reliant on both nuclear localization of Yap and interaction with a Tead co-factor. In contrast to loss of Yap and Taz, overexpression of either protein within optic vesicle progenitors leads to ectopic pigmentation in a dosagedependent manner. Overall, this study identifies Yap and Taz as key early regulators of RPE genesis and provides a mechanistic framework for understanding the congenital ocular defects of Sveinsson’s chorioretinal atrophy and congenital retinal coloboma. 60 pooled eyes from 36 hpf wild type or vsx2:Gal4/dsRed:14xUAS:YapS87A embryos were pooled for one sample. Three wild type and three vsx2:Gal4/dsRed:14xUAS:YapS87A pools were analyzed for RNA.