Project description:The BMP/TGFβ-Smad, Notch and VEGF signaling guides formation of endothelial tip and stalk cells. However, the crosstalk of bone morphogenetic proteins (BMPs) and vascular endothelial growth factor receptor 2 (VEGFR2) signaling has remained largely unknown. We demonstrate that BMP family members regulate VEGFR2 and Notch signaling, and act via TAZ-Hippo signaling pathway. BMPs were found to be regulated after VEGF gene transfer in C57/Bl6 mice and in a porcine myocardial ischemia model. BMPs 2/4/6 were identified as endothelium-specific targets of VEGF. BMP2 modulated VEGF-mediated endothelial sprouting via Delta like Canonical Notch Ligand 4 (DLL4). BMP6 modulated VEGF signaling by regulating VEGFR2 expression and acted via Hippo signaling effector TAZ, known to regulate cell survival/proliferation, and to be dysregulated in cancer. In a matrigel plug assay in nude mice BMP6 was further demonstrated to induce angiogenesis. BMP6 is the first member of BMP family found to directly regulate both Hippo signaling and neovessel formation. It may thus serve as a target in pro/anti-angiogenic therapies.
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:Osteogenesis is influenced by a variety of factors including growth factors - especially those of the TGF-beta superfamily - and Hippo signaling. Consequently, we hypothesize that the YAP/TAZ pathway is intertwining with TGF-beta and BMP signaling resulting in osteogenic differentiation. Therefore, we performed a comprehensive RNA-Seq study including both YAP/TAZ depletion by siRNA and BMP stimulation conditions in human fetal osteoblasts cell line hFOB 1.10. In order to identify the direct SMAD1 target genes corresponding to our RNA-Seq data, we performed an SMAD1 chromatin immunoprecipitation followed by sequencing.
Project description:The Hippo pathway downstream effectors, Yap and Taz, play key roles in cell proliferation and tissue growth, regulating gene expression especially via interaction with Tead transcription factors. To investigate their role in skeletal muscle stem cells, we analysed gene expression changes driven by Taz and compared these to Yap mediated changes to the transcriptome by measurement of gene expression on Affymetrix microarrays. To interrogate overlapping and unique transcriptional changes driven by these Hippo effectors, satellite cell-derived myoblasts were transduced with constitutively active TAZ S89A or YAP S127A retrovirus for 24h or 48h, with empty retrovirus as control. Triplicate microarray analyses of empty vector controls, hYAP1 S127A and TAZ S89A transgenic primary myoblasts were conducted.
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:The Hippo pathway is an emerging signaling cascade involved in the regulation of organ size control. It consists of evolutionally conserved protein kinases that are sequentially phosphorylated and activated. The active Hippo pathway subsequently phosphorylates a transcription coactivator, YAP, which precludes its nuclear localization and transcriptional activation. Identification of transcriptional targets of YAP in diverse cellular contexts is therefore critical to the understanding of the molecular mechanisms in which the Hippo pathway restricts tissue growth. We used microarrays to profile the gene expression patterns upon acute siRNA knockdown of Hippo pathway components in multiple mammalian cell lines and identified a set of genes representing immediate transcriptional targets of the Hippo/Yap signaling pathway. Three mammalian cell lines (HEK293T, HepG2, HaCaT) were transfected with scramble siRNA controls or siRNAs against NF2 and LATS2, two core components of the Hippo pathway, simultaneously. Total RNAs were harvested four days after transfection to reveal the gene expression pattern unsing microarry. YAP and TAZ siRNAs were also transfected along with NF2 and LATS2 siRNAs to identify YAP/TAZ-dependent transcriptional targets upon loss of NF2/LATS2.