Inducible smooth muscle specific deletion of Yap1/Wwtr1 in mouse
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ABSTRACT: YAP and TAZ are transcriptional co-activators and downstream effectors of the Hippo pathway, which play crucial roles in organ size control and cancer pathogenesis. Genetic deletion of YAP/TAZ has revealed their critical importance for embryonic development of the heart, vasculature and gastrointestinal mesenchyme. The aim of this study was to determine the functional role of YAP/TAZ in adult smooth muscle cell in vivo.
Project description:YAP and TAZ are transcriptional co-activators and downstream effectors of the Hippo pathway, which play crucial roles in organ size control and cancer pathogenesis. Genetic deletion of YAP/TAZ has revealed their critical importance for embryonic development of the heart, vasculature and gastrointestinal mesenchyme. The aim of this study was to determine the functional role of YAP/TAZ in adult smooth muscle cell in vivo.
Project description:YAP and TAZ are transcriptional co-activators and downstream effectors of the Hippo pathway, which play crucial roles in organ size control and cancer pathogenesis. Genetic deletion of YAP/TAZ has revealed their critical importance for embryonic development of the heart, vasculature and gastrointestinal mesenchyme. The aim of this study was to determine the long term role of YAP/TAZ in adult vascular smooth muscle in vivo. We used the novel Itga8-CreERT2 mouse for deletion of YAP/TAZ (i8-Y/T-KO).
Project description:TAZ, also known as WWTR1, is the one of the effectors of Hippo pathway. With its paralog, YAP, TAZ promotes organ size growth as well as tumor metastasis. In human renal carcinoma cells, we found that TAZ-silencing induces resisntance toward erastin-induced ferroptosis. In this study, TAZ is silencing in clear cell carcinoma cell line RCC4 to elucidate the downstream targets that promotes the resistance toward erastin-induced ferroptosis.
Project description:Aims: Hippo signalling is an evolutionarily conserved pathway that controls organ size by regulating apoptosis, cell proliferation and stem cell self-renewal. Recently, the pathway has been shown to exert powerful growth regulatory activity in cardiomyocytes. However, the functional role of this stress- and cell death-related pathway in the human heart and cardiomyocytes is not known. In this study, we investigated the role of the transcriptional co-activators of Hippo signalling, YAP and TAZ, in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) in response to cardiotoxic agents and investigated the effects of modulating the pathway on cardiomyocyte function and survival. Methods and Results: RNA sequencing analysis of human heart samples with doxorubicin-induced end-stage heart failure and healthy controls showed YAP and ERBB2 (HER2) as upstream regulators of differentially expressed genes correlated with doxorubicin treatment. Thus, we tested the effects of doxorubicin and/or small molecule inhibitor lapatinib on hiPSC-CM in vitro . Using an automated high contentscreen of 96 clinically relevant chemotherapeutic drugs, we showed that doxorubicin induced the highest activation of YAP/TAZ nuclear translocation in both hiPSC-CM and control MCF7 breast cancer cells. The overexpression of YAP rescued doxorubicin- induced cell loss in hiPSC-CM by inhibiting apoptosis and inducing proliferation. In contrast, silencing of YAP and TAZ by siRNAs resulted in elevated mitochondrial membrane potential loss in response to doxorubicin. Human iPSC-CM calcium transients did not change in response to YAP/TAZ silencing. Conclusions: Our results suggest that Hippo signalling is involved in clinical anthracycline-induced cardiomyopathy. Modelling with hiPSC-CM in vitro showed similar responses to doxorubicin as adult cardiomyocytes and revealed a potential cardioprotective effect of YAP in doxorubicin-induced cardiotoxicity.
Project description:Podocytes are terminally differentiated cells at the kidney filtration barrier and exposed to considerable mechanical strain. Podocyte injury causes morphological changes as a result of cytoskeletal reorganizations and failure of the filtration barrier. The transcriptional co-activators YAP/TAZ are tightly controlled through hippo signaling and responsive to mechanical cues. Here, we show that YAP is upregulated upon podocyte injury to activate YAP-dependent target genes. This activation preceded the development of proteinuria. In contrast, similar perturbations of cells in culture did not reveal increased YAP activity but showed a downregulation of YAP/TAZ activity when cells were grown on stiff surface. However, culture of cells on soft matrix or inhibition of stress fiber formation allowed recapitulation of the damage-induced YAP upregulation indicating a mechanotransduction-dependent mechanism of YAP over-activity. Interestingly, increased expression of YAP targets was confirmed in renal biopsies from patients with glomerular disease. Consistently, pharmacological inhibition of YAP/TEAD activity ameliorated glomerular disease in vivo. These data suggest that perturbation of the mechanosensitive hippo signaling pathway may be a therapeutic principle in podocyte disease.
Project description:Podocytes are terminally differentiated cells at the kidney filtration barrier and exposed to considerable mechanical strain. Podocyte injury causes morphological changes as a result of cytoskeletal reorganizations and failure of the filtration barrier. The transcriptional co-activators YAP/TAZ are tightly controlled through hippo signaling and responsive to mechanical cues. Here, we show that YAP is upregulated upon podocyte injury to activate YAP-dependent target genes. This activation preceded the development of proteinuria. In contrast, similar perturbations of cells in culture did not reveal increased YAP activity but showed a downregulation of YAP/TAZ activity when cells were grown on stiff surface. However, culture of cells on soft matrix or inhibition of stress fiber formation allowed recapitulation of the damage-induced YAP upregulation indicating a mechanotransduction-dependent mechanism of YAP hyper-activity. Interestingly, increased expression of YAP targets was confirmed in renal biopsies from patients with glomerular disease. Consistently, pharmacological inhibition of YAP/TEAD activity ameliorated glomerular disease in vivo. These data suggest that perturbation of the mechanosensitive hippo signaling pathway may be a therapeutic principle in podocyte disease.
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.
Project description:Dysregulation of the Hippo pathway and the consequent activation of its downstream targets, the transcriptional co-activators YAP and TAZ (YAP/TAZ), drives oncogenic transcriptional programs upon binding TEAD transcription factors in multiple human malignancies. The recent development of small molecule TEAD inhibitors (smTEADi) provides an opportunity to therapeutically target Hippo pathway dysregulation in cancer. In this regard, HPV-negative head and neck squamous cell carcinoma (HNSCC) harbor multiple genetic alterations that promote YAP/TAZ hyperactivation, raising the possibility that HNSCC cells might be dependent on YAP/TAZ-TEAD driven oncogenic transcriptional programs. To test this hypothesis, we examined the antitumor activity of the novel smTEADi, SW-682 and genetically encoded TEAD inhibitor peptide (pTEADi) in Cal33 HPV-negative HNSCC cell line-derived xenograft model. To elucidate the transcriptomic changes upon YAP/TAZ-TEAD inhibition, RNA extracted from xenograft tumors treated with SW-682 or pTEADi, as well as control, was subjected to RNA sequencing.