GPCR-induced YAP activation sensitizes fibroblasts to profibrotic effects of TGFβ1
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ABSTRACT: Fibrosis is an uncontrolled wound healing process resulting from tissue injury, inflammation and fibroblast activation, finally leading to accumulation of extracellular matrix (ECM) components in tissues and to organ failure. The underlying mechanisms of fibrosis have been intensely studied and it has become clear that multiple pathways and their crosstalk regulate fibrotic diseases with a few central players, including TGFβ1. Recently, YAP and TAZ were implicated in fibrosis as one of the essential components of its pathogenesis. YAP/TAZ are known to crosstalk with the TGFβ pathway in the nucleus and regulate its activity on transcriptional level by binding to Smad2/3/4 complexes. We hypothesized that factors, such as GPCR ligands which regulate YAP/TAZ, might modulate the profibrotic responses to TGFβ1. We performed gene expression microarray in NHDF treated with TGFβ1, LPA, the combination of TGFβ1/LPA or vehicle. The aim was to have a broader look at transcriptional signatures induced by the individual treatments and in the combination of TGFβ1 and LPA.
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:Idiopathic pulmonary fibrosis is a chronic devastating disease of unknown etiology. No therapy is currently available. A growing body of evidence supports the role of TGFβ1 as the major player in the pathogenesis of the disease. This study designed novel human- and mouse-specific siRNAs and siRNA/DNA chimeras targeting both human and mouse common sequences and evaluated their inhibitory activity in pulmonary fibrosis induced by bleomycin and lung-specific transgenic expression of human TGFβ1. Selective novel sequences of siRNA and siRNA/DNA chimeras efficiently inhibited pulmonary fibrosis, indicating their applicability as tools for treating fibrotic disease in humans. Total RNA was extracted from lung tissue from mice with bleomycin (BLM)-induced lung fibrosis treated with mouse TGFβ1 siRNAs or vehicle on different days after BLM infusion.
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.
Project description:Fibrotic diseases account for nearly half of all deaths in the developed world. Despite its importance, the pathogenesis of fibrosis remains poorly understood. Recently, the two mechanosensitive transcription cofactors YAP and TAZ have emerged as important profibrotic regulators in multiple murine tissues. Despite this growing recognition, a number of important questions remain unanswered, including which cell types require YAP/TAZ activation for fibrosis to occur and the time course of this activation. Here, we present a detailed analysis of the role that myofibroblast YAP and TAZ play in organ fibrosis and the kinetics of their activation. Using analyses of cells, as well as multiple murine and human tissues, we demonstrated that myofibroblast YAP and TAZ were activated early after organ injury and that this activation was sustained. We further demonstrated the critical importance of myofibroblast YAP/TAZ in driving progressive scarring in the kidney, lung, and liver, using multiple transgenic models in which YAP and TAZ were either deleted or hyperactivated. Taken together, these data establish the importance of early injury-induced myofibroblast YAP and TAZ activation as a key event driving fibrosis in multiple organs. This information should help guide the development of new antifibrotic YAP/TAZ inhibition strategies.
Project description:4 replicates were prepared from A2058 melanoma cells [transfected with 10ng of empty vector (pcDNA3.1+)] and treated with 5ng/ml TGFβ1 or vehicle control for 24hrs This is the control arm of a larger experiment where cells transfected with a particular expression plasmid were treated with TGFβ1 or control vehicle. The transfection with the expresion plasmid was unsucessful so this empty vector data has been used alone to simply examine the effect of TGFβ1 treatment on A2058 cells.
Project description:Peritoneal fibrosis is a major complication of long-term peritoneal dialysis (PD), leading to ultrafiltration failure and sometimes life threatening encapsulating peritoneal sclerosis. Fibrosis is driven by activated myofibroblasts that are derived, in part, from mesothelial-to-mesenchymal transition (MMT). We aimed to discover novel mediators of MMT and then experimentally exploit them to prevent peritoneal fibrosis. Using an antibody to HBME-1 and streptavidin nanobead technology, we first pioneered a novel method to purify rat mesothelial cells. After exposing mesothelial cells to transforming growth factor β1 (TGFβ1), we undertook RNAseq whole transcriptome analyses and outlined, the expression profile of sorted mesothelial cells at pre- and post- MMT.
Project description:The factors regulating cellular identity are critical for understanding the transition from health to disease and responses to therapies. Cell identity is generally assigned based on static phenotypes, like “omics” profiles. However, how such static features translate into dynamic responses to perturbations that determine cellular function is often unclear. We found that autophagy perturbation in different cell types can have opposite responses in growth-promoting oncogenic YAP/TAZ transcriptional signalling. These apparently contradictory responses can be resolved by a feedback loop where autophagy negatively regulates the levels of α-catenins LC3-interacting proteins, which inhibit YAP/TAZ, which, in turn, positively regulate autophagy. High basal levels of α-catenins enable autophagy induction to positively regulate YAP/TAZ, while low α-catenins cause YAP/TAZ activation upon autophagy inhibition. These data reveal how feedback loops enable post-transcriptional determination of cell identity and how levels of a single intermediary protein can dictate the direction of response to external or internal perturbations.
Project description:Idiopathic pulmonary fibrosis is a chronic devastating disease of unknown etiology. No therapy is currently available. A growing body of evidence supports the role of TGFβ1 as the major player in the pathogenesis of the disease. This study designed novel human- and mouse-specific siRNAs and siRNA/DNA chimeras targeting both human and mouse common sequences and evaluated their inhibitory activity in pulmonary fibrosis induced by bleomycin and lung-specific transgenic expression of human TGFβ1. Selective novel sequences of siRNA and siRNA/DNA chimeras efficiently inhibited pulmonary fibrosis, indicating their applicability as tools for treating fibrotic disease in humans.
Project description:Idiopathic pulmonary fibrosis (IPF) is a life-threatening and progressive scarring disease of the lung. Loss of alveolar epithelial cells, inflammation, activation of fibroblasts, appearance of myofibroblasts and excessive deposition of extracellular matrix (ECM) are central features of IPF pathogenesis, ultimately resulting in changes in tissue architecture and lung dysfunction. The two currently approved therapies, pirfenidone (Esbriet®) and nintedanib (Ofev®), significantly slow the rate of disease progression, but they do not halt or reverse tissue remodeling. Therefore, disease modifying strategies that influence (myo)fibroblast activity and ECM deposition could lead to promising new treatments. Here we demonstrate potent and effective in vitro antifibrotic properties of the selective prostacyclin (IP) receptor agonist, ACT-333679, on TGFβ1-stimulated primary human lung fibroblasts from non-diseased and IPF donors. We demonstrate that ACT-333679 inhibited fibrotic processes through elevation of cAMP, inhibition of YAP/TAZ signaling and subsequent suppression of YAP/TAZ-induced gene transcription. Our results describe attenuation of YAP/TAZ signaling through IP receptor activation as a novel mechanism that suppresses pro-fibrotic (myo)fibroblast activity and we offer a rationale to further explore the potential of IP receptor agonists for the treatment of IPF .