Hepatocyte-specific YAP is crucial for CAR-driven hepatocyte proliferation, but not for induction of drug metabolism genes in mice
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PROVIDER: PRJNA625193 | ENA |
REPOSITORIES: ENA
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Project description:Constitutive androstane receptor (CAR) agonists, such as TCPOBOP, are known to cause robust hepatocyte proliferation and hepatomegaly in mice along with induction of drug metabolism genes, without any associated liver injury. Yes-associated protein (YAP) is a key transcription regulator that tightly controls organ size including that of liver. Ours and other previous studies suggested increased nuclear localization and activation of YAP after TCPOBOP treatment in mice and potential role of YAP in CAR-driven proliferative response. Here, we investigated a direct role of YAP in CAR-driven hepatomegaly and hepatocyte proliferation using hepatocyte-specific YAP-KO mice. AAV8-TBG-CRE vector was injected to YAP-floxed mice for achieving hepatocyte-specific YAP deletion followed by TCPOBOP treatment. YAP deletion did not alter protein expression of CAR or CAR-driven induction of drug metabolism genes (including Cyp2b10, Cyp2c55 and UGT1a1). However, YAP deletion substantially reduced TCPOBOP-induced hepatocyte proliferation. TCPOBOP-driven cell cycle activation was disrupted in YAP-KO mice due to delayed (and decreased) induction of cyclin D1 and higher expression of p21, resulting in decreased phosphorylation of retinoblastoma (Rb) protein. Further, induction of other cyclins, which are sequentially involved in progression through cell cycle (including cyclin E1, A2 and B1) and important mitotic regulators (such as aurora B kinase and polo-like kinase 1) was remarkably reduced in YAP-KO mice. Microarray analysis revealed that 26% of TCPOBOP‐responsive genes mainly related to proliferation, but not to drug metabolism, were altered by YAP deletion. YAP regulated these proliferation genes via alerting expression of cMyc and FOXM1, two critical transcriptional regulators of CAR-mediated hepatocyte proliferation. Conclusion: Our study revealed an important role of YAP signaling in CAR-driven hepatocyte proliferation; however, CAR-driven induction of drug metabolism genes was independent of YAP. We used microarrays to detail the global programme of gene expression in livers of hepatocyte-specific YAP KO mice following TCPOBOP treatment
2021-09-09 | GSE148607 | GEO
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. Yap wild type ChIPseq and input
2015-02-20 | E-GEOD-57717 | biostudies-arrayexpress
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.
2015-02-20 | E-GEOD-57718 | biostudies-arrayexpress
Project description:It has been a long-standing challenge to maintain the functions of hepatocytes in vitro. In the present study, we found that mechanical tension-induced yes-associated protein (Yap) activation triggered hepatocyte dedifferentiation. Alleviation of mechanical tension by confinement of cell spreading was sufficient to inhibit hepatocyte dedifferentiation. Based on this finding, we identified a small molecular cocktail LBDXL through reiterative chemical screening that could maintain hepatocyte functions over the long term and in vivo repopulation capacity by targeting actin polymerization and actomyosin contraction.
2019-10-30 | GSE138158 | GEO
Project description:The transcriptional coactivator Yap promotes proliferation and inhibits apoptosis, suggesting that Yap functions as an oncogene. Most oncogenes, however, require a combination of at least two signals to promote proliferation. Here we present evidence that Yap activation is insufficient to promote growth in the otherwise normal tissue. Using a mosaic mouse model, we demonstrate that Yap overexpression in a fraction of hepatocytes does not lead to their clonal expansion, as proliferation is counterbalanced by increased apoptosis. To shift the activity of Yap towards growth, a second signal provided by tissue damage or inflammation is required. In response to liver injury, Yap drives clonal expansion, suppresses hepatocyte differentiation and promotes a progenitor phenotype. These results suggest that Yap activation is insufficient to promote growth in the absence of a second signal thus coordinating tissue homeostasis and repair. Totally sixteen samples
2015-02-07 | E-GEOD-65207 | biostudies-arrayexpress
Project description:Defective Hippo/YAP signaling in the liver results in tissue overgrowth and development of hepatocellular carcinoma (HCC). Here, we uncover mechanisms of YAP-mediated hepatocyte reprogramming and HCC pathogenesis. We show that YAP functions as a rheostat maintaining metabolic specialization, differentiation and quiescence within the hepatocyte compartment. Importantly, treatment with siRNA-lipid nanoparticles (siRNA-LNPs) targeting YAP restores hepatocyte differentiation and causes pronounced tumor regression in a genetically engineered mouse HCC model (mice with liver-specific Mst1/Mst2 double knockout). Furthermore, YAP targets are enriched in an aggressive human HCC subtype characterized by a proliferative signature and absence of CTNNB1 mutations. Thus, our work reveals Hippo signaling as a key regulator of positional identity of hepatocytes, supports targeting YAP using siRNA-LNPs as a paradigm of differentiation-based therapy, and identifies an HCC subtype potentially responsive to this approach. Mice with liver-specific Mst1/Mst2 double-knockout (Adeno-Cre injected Mst1-/-; Mst2Flox/Flox mice) were monitored for the formation of HCC by ultrasound imaging. Animals were then randomized to be treated by intravenous injection of either siYap-LNPs or siLuciferase-LNPs for a period of 9 days.
2015-03-07 | E-GEOD-65665 | biostudies-arrayexpress
Project description:TCPOBOP (1,4-Bis [2-(3,5-Dichloropyridyloxy)] benzene) is a constitutive androstane receptor (CAR) agonist that induces robust hepatocyte proliferation and hepatomegaly without any liver injury or tissue loss. TCPOBOP-induced direct hyperplasia has been considered to be CAR-dependent with no evidence of involvement of cytokines or growth factor signaling. Receptor tyrosine kinases (RTKs), MET and EGFR, are known to play a critical role in liver regeneration after partial hepatectomy, but their role in TCPOBOP-induced direct hyperplasia, not yet explored, is investigated in the current study. Disruption of the RTK-mediated signaling was achieved utilizing MET KO mice along with Canertinib treatment for EGFR inhibition. Combined elimination of MET and EGFR signaling [MET KO + EGFRi], but not individual disruption, dramatically reduced TCPOBOP-induced hepatomegaly and hepatocyte proliferation. TCPOBOP-driven CAR activation was not altered in [MET KO + EGFRi] mice, as measured by nuclear CAR translocation and analysis of typical CAR target genes. However, TCPOBOP induced cell cycle activation was impaired in [MET KO + EGFRi] mice due to defective induction of cyclins, which regulate cell cycle initiation and progression. TCPOBOP-driven induction of FOXM1, a key transcriptional regulator of cell cycle progression during TCPOBOP-mediated hepatocyte proliferation, was greatly attenuated in [MET KO + EGFRi] mice. Interestingly, TCPOBOP treatment caused transient decline in HNF4α expression concomitant to proliferative response; this was not seen in [MET KO + EGFRi] mice. Transcriptomic profiling revealed vast majority (~40%) of TCPOBOP-dependent genes mainly related to proliferative response, but not to drug metabolism, were differentially expressed in [MET KO + EGFRi] mice. Conclusion: Taken together, combined disruption of EGFR and MET signaling lead to dramatic impairment of TCPOBOP-induced proliferative response without altering CAR activation. We used microarrays to detail the global programme of gene expression in [METKO + EGFRi] mice liver following TCPOBOP treatment
2018-08-28 | GSE110695 | GEO
Project description:We conditionally knocked out both Yap and Taz in cranial neural crest (CNC) using the Wnt1Cre driver and sequenced mRNA from embryonic day 10.5 mandibles. Examination of mRNA level in E10.5 mandibular tissues from control and Wnt1Cre Taz and Yap dKO mutant.
2016-03-01 | E-GEOD-69311 | biostudies-arrayexpress
Project description:The Hippo/YAP signaling pathway is a crucial regulator of tissue growth and stem cell activity. YAP is also a powerful driver of tumor growth and its nuclear accumulation is frequently observed in human cancer. However, the molecular mechanism employed by YAP to orchestrate transcriptional outputs are undefined. Here, we utilize genomic technologies to demonstrate that YAP occupancy is restricted to a small number of distal regulatory elements highly enriched for superenhancers. Target genes associated with these elements are selectively sensitive to the loss of YAP in cancer cells. YAP directs recruitment of the Mediator complex to activate transcriptional regulation from these enhancers without affecting chromatin organization We also provide in vivo genetic evidence that loss of Mediator rescues YAP-driven cancer cell proliferation and organ overgrowth. Our data provide a molecular mechanism behind YAP-driven tumorigenesis, and highlights transcriptional control as a potential therapeutic strategy for YAP-driven cancers.
2017-10-10 | GSE62274 | GEO
Project description:The Hippo/YAP signaling pathway is a crucial regulator of tissue growth and stem cell activity. YAP is also a powerful driver of tumor growth and its nuclear accumulation is frequently observed in human cancer. However, the molecular mechanism employed by YAP to orchestrate transcriptional outputs are undefined. Here, we utilize genomic technologies to demonstrate that YAP occupancy is restricted to a small number of distal regulatory elements highly enriched for superenhancers. Target genes associated with these elements are selectively sensitive to the loss of YAP in cancer cells. YAP directs recruitment of the Mediator complex to activate transcriptional regulation from these enhancers without affecting chromatin organization We also provide in vivo genetic evidence that loss of Mediator rescues YAP-driven cancer cell proliferation and organ overgrowth. Our data provide a molecular mechanism behind YAP-driven tumorigenesis, and highlights transcriptional control as a potential therapeutic strategy for YAP-driven cancers.
2015-10-01 | GSE62272 | GEO