Role Of Hippo Pathway Research Articles

Role of hippo pathway and cuproptosis-related genes in immune infiltration and prognosis of skin cutaneous melanoma.

Melanoma is the most lethal type of skin cancer with an increasing incidence. Cuproptosis is the most recently identified copper-dependent form of cell death that relies on mitochondrial respiration. The hippocampal (Hippo) pathway functions as a tumor suppressor by regulating Yes-associated protein/transcriptional coactivator with PDZ-binding motif (YAP/TAZ) activity. However, its role in cuproptosis remains unknown. In addition, the correlation of cuproptosis-related genes and Hippo pathway-related genes with tumor prognosis warrants further investigation. In the present study, we explored the correlation of cuproptosis-related genes and Hippo pathway-related genes with the prognosis of melanoma through analysis of data from a public database and experimental verification. We found eight Hippo pathway-related genes that were downregulated in melanoma and exhibited predictive value for prognosis. There was a significant positive correlation between cuproptosis-related genes and Hippo pathway-related genes in skin cutaneous melanoma. YAP1 expression was positively correlated with ferredoxin 1 (FDX1) expression in the GSE68599 dataset and A2058 cells. Moreover, YAP1 was positively and negatively correlated with M2 macrophages and regulatory T cell infiltration, respectively. In conclusion, the present study demonstrated the prognostic value of Hippo pathway-related genes (particularly YAP1) in melanoma, revealing the correlation between the expression of Hippo pathway-related genes and immune infiltration. Thus, the present findings may provide new clues on the prognostic assessment of patients with melanoma and a new target for the immunotherapy of this disease.

Treatment development targeting Hippo pathway for scirrhous type gastric cancer.

398 Background: Treatment outcome of gastric cancer (GC) has been improved by minimally invasive surgery, and development of new drugs including immune checkpoint inhibitors. However, survival for patients with scirrhous type (SGC, Type4) gastric cancer is dismal. Methods: We collected miRNAs form exosomes released from cancer associated fibroblasts which is developed from resected gastric cancer tissue. Pathway enrichment analysis (PEA) of top miRNAs showed that they are significantly associated with Hippo signaling pathway (Hippo pathway). The molecules relating Hippo pathway was evaluated by Western blotting in cell line, and IHC of tissue array. Results: PEA using top miRNAs showed the significant relationship to Hippo pathway. Yap is a final effector in this pathway, and we found that YAP is not expressed in MKN45 cells (diffuse type), which is supposed to be degraded in cytoplasm. On the contrary, MKN74 cells express both YAP and pYAP. IHC showed that YAP translocation to nucleus is significantly associated with CTGF expression. CTGF low expression is significantly associated with worse prognosis especially in diffuse type GC (Log rank p = 0.022). This trend is similar in the analysis of patients with SGC. Conclusions: The role of Hippo pathway is different between intestinal type and diffuse type of GC. YAP activator could be effective for the treatment of SGC, and we are focusing on the treatment development.

The role of Hippo pathway in ovarian development.

The follicle is the functional unit of the ovary, whereby ovarian development is largely dependent on the development of the follicles themselves. The activation, growth, and progression of follicles are modulated by a diverse range of factors, including reproductive endocrine system and multiple signaling pathways. The Hippo pathway exhibits a high degree of evolutionary conservation between both Drosophila and mammalian systems, and is recognized for its pivotal role in regulating cellular proliferation, control of organ size, and embryonic development. During the process of follicle development, the components of the Hippo pathway show temporal and spatial variations. Recent clinical studies have shown that ovarian fragmentation can activate follicles. The mechanism is that the mechanical signal of cutting triggers actin polymerization. This process leads to the disruption of the Hippo pathway and subsequently induces the upregulation of downstream CCN and apoptosis inhibitors, thereby promoting follicle development. Thus, the Hippo pathway plays a crucial role in both the activation and development of follicles. In this article, we focused on the development and atresia of follicles and the function of Hippo pathway in these processes. Additionally, the physiological effects of Hippo pathway in follicle activation are also explored.

The role of Hippo pathway in ferroptosis.

The role of Hippo pathway in ferroptosis The Hippo pathway is mainly composed of mammalian serine/threonine (Ste20)like kinases 1/2 (MST1/2), large tumor suppressor 1/2 (LATS1/2), and transcriptional coactivator Yes-associated protein (YAP), and is closely related to cell growth, survival, proliferation, and migration; tissue and organ size control; and tumorigenesis and development. Ferroptosis is a regulated form of cell death characterized by the accumulation of iron-dependent reactive oxygen species (ROS) and the depletion of plasma membrane polyunsaturated fatty acids (PUFAs), which is caused by the imbalance of oxidation and the antioxidant system. This article elaborates the role of Hippo pathway in ferroptosis, providing ideas for the regulation of cell fate and the treatment of tumors.

Abstract 13994: Single-Dose Intervention With Rapamycin at Reperfusion Preserves Cardiac Function Through Attenuation of Inflammation and Increased Cardiomyocyte Proliferation in Diabetic Rabbit- Role of Hippo Pathway

Background: Rapamycin (RAPA, mTOR inhibitor) given at reperfusion protects diabetic rabbit hearts against ischemia/reperfusion (I/R) injury by reducing infarct size and apoptosis. We hypothesized that RAPA administration may preserve post-ischemic cardiac function through decreased inflammation and increased cardiomyocyte proliferation with regulation of YAP- the effector of Hippo pathway). Methods and Results: Diabetes (DM) was induced by administration of alloxan monohydrate (125 mg/kg, i.v.) in New Zealand rabbits (n=12; body weight≈3 kg, 4-month-old). Four weeks after alloxan treatments, conscious diabetic rabbits (maintaining blood glucose>250 mg/dL) were subjected to 45 min of ischemia and 10 days of reperfusion (R) by inflating/deflating previously implanted hydraulic balloon occluder. RAPA (0.25 mg/kg, i.v.) or DMSO (vehicle) was infused 5 min before onset of R. Post-I/R cardiac function in diabetic rabbit, assessed by echocardiography, showed significant improvement of ejection fraction (EF, Fig. A ). Left ventricular fibrosis ( Fig. B , evaluated by picrosirius red staining) was attenuated following treatment of RAPA in diabetic rabbits. Immunofluorescence staining revealed the attenuation of post-I/R inflammasome formation with RAPA treatment as shown by reduced ASC aggregation (apoptosis speck-like protein with a caspase recruitment domain) in cardiomyocytes ( Fig. C ). RAPA suppressed the phosphorylation of YAP in cytosol of cardiomyocytes ( Fig. D ). Proliferation markers, Ki-67 positive and phospho-Aurora B Kinase positive cells indicated cardiomyocytes were in G2-M phase in RAPA-treated diabetic rabbits after I/R injury ( Fig. E ). Conclusion: RAPA treatment at reperfusion preserves cardiac function and improves cardiomyocyte proliferation with attenuation of inflammation and possibly regulation of Hippo pathway following I/R injury in diabetes.

Human Umbilical Cord Mesenchymal Stem Cell-Derived Exosomes Improve Ovarian Function and Proliferation of Premature Ovarian Insufficiency by Regulating the Hippo Signaling Pathway.

BackgroundPremature ovarian insufficiency (POI) is associated with severe physical damage and psychological burden on women. Transplantation of exosomes is an encouraging regenerative medicine method, which has the potential for restoring ovarian functions on POI with high efficiency. This study aims at evaluating the therapeutic efficacy of human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-Exos) on ovarian dysfunction of POI and the role of Hippo pathway in this exosome-mediated treatment.MethodsPOI mice models were established through intraperitoneal injection of cyclophosphamide. Subsequently, transplantation of hUCMSC-Exos was conducted to administer POI mice. Ovaries and plasma of these mice models were harvested after two weeks of treatment. Ovarian morphology and follicle number were assessed by hematoxylin and eosin staining. Moreover, ELISA was used to detect hormone levels, which are related to ovarian function in serum. To assess the recovery of reproductive ability, we recorded the rate of pregnancy, the amount of offspring, and the time of birth in different groups. To explore the underlying mechanisms of exosome-mediated treatment for ovarian function recovery, the proliferation of ovarian cells in vivo was detected by immunohistochemistry and immunofluorescence staining. Additionally, we conducted EdU and CCK-8 assays to assess the proliferative ability of ovarian granulosa cells (GCs) that were cultured in vitro. Western blot analysis was conducted to estimate the proteins levels of Hippo- and proliferation-associated molecules in vivo and in vitro.ResultsAfter transplantation of hUCMSC-Exos, the ovarian function-related hormone levels and the number of ovarian follicles returned to nearly normal degrees. Meanwhile, there was a significant improvement in reproductive outcomes after exosomal treatment. Furthermore, the improvement of ovarian function and proliferation was associated with the regulation of Hippo pathway. In vitro, co-culture with exosomes significantly elevated the proliferation of ovarian GCs by regulating Hippo pathway. However, the positive effects on the proliferation of GCs were significantly depressed when key Hippo pathway molecule was inhibited.ConclusionThis study suggested that hUCMSC-Exos promoted ovarian functions and proliferation by regulating the Hippo pathway. Therefore, exosomal transplantation could be a promising and efficient clinical therapy for POI in the near future.

YAP promotes the activation of NLRP3 inflammasome via blocking K27-linked polyubiquitination of NLRP3

The transcription coactivator YAP plays a vital role in Hippo pathway for organ-size control and tissue homeostasis. Recent studies have demonstrated YAP is closely related to immune disorders and inflammatory diseases, but the underlying mechanisms remain less defined. Here, we find that YAP promotes the activation of NLRP3 inflammasome, an intracellular multi-protein complex that orchestrates host immune responses to infections or sterile injuries. YAP deficiency in myeloid cells significantly attenuates LPS-induced systemic inflammation and monosodium urate (MSU) crystals-induced peritonitis. Mechanistically, YAP physically interacts with NLRP3 and maintains the stability of NLRP3 through blocking the association between NLRP3 and the E3 ligase β-TrCP1, the latter increases the proteasomal degradation of NLRP3 via K27-linked ubiquitination at lys380. Together, these findings establish a role of YAP in the activation of NLRP3 inflammasome, and provide potential therapeutic target to treat the NLRP3 inflammasome-related diseases.

The Hippo pathway: a renewed insight in the craniofacial diseases and hard tissue remodeling.

The Hippo pathway plays an important role in many pathophysiological processes, including cell proliferation and differentiation, cell death, cell migration and invasion. Because of its extensive functions, Hippo pathway is closely related to not only growth and development, but also many diseases, including inflammation and cancer. In this study, the role of Hippo pathway in craniofacial diseases and hard tissue remodeling was reviewed, in attempting to find new research directions.

The Hippo Show Must Go On: YAP Activation as a Therapeutic Strategy in Colorectal Cancer.

The role of Hippo pathway in colorectal cancer (CRC) initiation and progression has been controversial. In this issue of Cell Stem Cell, Cheung etal. (2020) shed new light on a distinct function of the transcriptional co-activator YAP as a tumor suppressor and Wnt pathway inhibitor in CRC.

Involvement of YAP and LATS1 in lung development in a rat model of nitrofen-induced congenital diaphragmatic hernia

Purpose: To investigate the role of Hippo pathway in lung development in congenital diaphragmatic hernia (CDH).
 Methods: One oral dose of nitrofen was maternally administered for induction of CDH on embryonic day 9.5 (E 9.5). Sildenafil was administered intragastrically at a dose of 100 mg/kg on E 11.5. Three rat groups were used: control, CDH, and CDH + sildenafil. Cesarean section was used for fetal delivery on E 21.5. Fetuses with left diaphragmatic hernia (except in control rats) were chosen for investigations. Fetal body weight and weight of lung tissue were recorded, and lung histological evaluation, western blot and PCR were carried out after lung processing.
 Results: There was markedly higher expression of YAP in CDH rats than in control rats was unaffected by antenatal sildenafil administration (p < 0.05). However, prenatal sildenafil intervention significantly increased LATS1 expression in the lung of CDH fetuses (p < 0.05).
 Conclusion: These results indicate that increased pulmonary YAP expression in CDH rat model might contribute to pulmonary vascular remodeling and suppression of lung development. Thus, antenatal sildenafil administration not only mitigates abnormal vascular remodeling but also promotes lung development, most likely via increased expression of LATS1.
 Keywords: Congenital diaphragmatic hernia (CDH), Hippo pathway, Lung development, Sildenafil

P5382Geometry and strain sensing dictate YAP-dependent evolution of human cardiac stromal cells toward myofibroblasts in the cardiosphere organoid model

Abstract Background Cardiac stromal cells are the most abundant cell type present in the heart, where they have an important homeostatic function in matrix renewal and electromechanical coupling. We have shown that YAP transcription factor (a component of the Hippo pathway) is important for the proliferation of these cells and, potentially, pathologic cardiac matrix stiffening in heart failure. Purpose Given the role of Hippo pathway in cell mechanosensation, we assessed the conditions for activation of the YAP-dependent transcriptional pathway related to geometry/strain sensing using human “cardiosphere”-derived cells. Methods Human cardiospheres (C-Sp) and C-Sp-derived cells (CDCs) were obtained from fragments of atrial appendages of patients admitted for AoC bypass. C-Sps and CDCs were cultured using published methods. To analyze cell/nuclear geometry in 2D/3D culture, we employed an adapting thresholding algorithm allowing segmentation of cell membrane/nuclei shape and the relative abundance of nuclear/cytoplasmic fluorescence intensities from z-stacked confocal immunofluorescence images. Inhibitors of signaling cascades converging onto actin cytoskeleton polymerization or of YAP/TEADs interaction were used to assess YAP target genes transcription. Results Previous results showed stiffness sensitivity of YAP nuclear translocation process. Namely, CDCs plated onto stiff (E >50kPa) culture plates exhibited high ratios of nuclear/cytoplasmic YAP, as compared to cells plated on substrates with lower stiffness (E ∼ 10kPa). Analogously, cells with a stretched cytoplasm/nuclear shape in the border regions of the 3D organoids exhibited a higher YAP nuclear localization level and expression of fibrotic markers compared with cells with a more round geometry in the center of the spheres. To uncouple the cytoskeleton tensioning-dependent YAP nuclear shuttling, we treated CDCs plated onto stiff substrates with blebbistatin and Y27632. This showed a fully reversible YAP relocation from the nucleus to the cytoplasm and a reversion of canonical target genes (CYR61, ANKRD1 and CTGF) expression. In parallel, a “softening” process of the nucleus, likely due to release from cytoskeleton traction forces, was observed by confocal imaging along the cellular z-axis. Interestingly, use of Verteporfin, a drug directly interfering with the interaction of YAP/TAZ complex with TEADs DNA binding proteins showed reversion of pro-fibrotic YAP targets independent of high cytoskeleton tensioning. Conclusions These results establish, for the first time, a deterministic relationship between pro-pathologic evolution of human adult cardiac stromal cells and activation of mechanosensing-dependent pathways. They also provide quantitative criteria for interpreting fibrotic evolution of the heart based on modifications of myocardial architecture and mechanical compliance, as well as the ability of the cells to generate tension forces affecting the nuclear structure.

YAP, A Component of the Hippo Pathway, is Essential for Antioxidant Defense

The highly conserved Hippo signaling pathway which negatively regulates cell growth and survival is a key regulator of organ size and tumorigenesis. Emerging evidence suggests the important role of Hippo pathway in response to oxidative stress. However the mechanism was rarely explored. Here we reported that YAP protein, which is the terminal effector of Hippo signaling pathway, shuttled between cytoplasm and nucleus following different concentration of sodium arsenite treatment, thereby controlling cell death or survival under arsenite-induced oxidative stress. Low concentration of sodium arsenite inhibited phosphorylation of YAP S127 and promoted YAP translocation to nucleus, thus further enhanced cell proliferation. However, high concentration of sodium arsenite augmented phosphorylation of YAP at S127 and induced translocation of YAP into cytoplasm and further caused cell apoptosis. These results suggest that YAP translocation plays an important role in deciding cell fate under arsenite-induced oxidative stress.

Cloning and Sequence Analysis of Hippo Pathway Related Major Genes of Silkworm (<i>Bombyx mori)</i>

Hippo kinase cascade shared by a variety of multicellular animals is appreciated as a signaling pathway which aims to inhibit the growth of cells and it is very conservative during evolution. Recent studies have confirmed that the Hippo signal pathway functions in cancer, tissue regeneration as well as stem cell regulation. The silkworm Bombyx mori is a model of Lepidopteran insect, little is known regarding genes related to Hippo kinase cascade. In the present study, the sequences of major genes related to Hippo pathway are obtained successfully in silkworm, B. mori, by in silico cloning or RT-PCR, including BmHop, BmSav, BmMats, BmWts and BmYki. The deduced amino acid sequences of the genes were aligned with those of other species, although the sequence identities of these proteins from different species were not high, the conserved domains were prominent, suggesting that the roles of Hippo pathway in the silkworm are similar to those in other species. These results has laid an important foundation for the further understanding and clarifying the function of the Hippo signaling pathway in silkworm.

Abstract 1146: STK4 downregulation promotes tumor invasion/migration and is associated with poor prognosis in human colon cancer.

Abstract Colon cancer has high incidence rate in the world and the early stage of colon cancer can be cured by surgical therapy. However, it remains difficult to predict the prognostic outcome of colon cancer patients. STK4 is considered as a potential tumor suppressor, which plays an important role in Hippo pathway to control the organ size and the inhibition ability of cell-cell contact. The major aim of this study is focused on the investigation of prognostic value of STK4 in colon cancer. By immunohistochemistry assay, we examined the expression of STK4 in 140 pairs normal and tumor colon cancer specimens. The relationship between STK4 expression and clinicopathological factors as well as patient survival were analyzed and the results showed that STK4 was significantly downregulated in tumor tissues compared to their corresponding non-tumor part (P<0.01) and that was significantly associated with tumor size (P=0.003), distal metastasis (P=0.03), disease recurrence and poor survival (P<0.005). Moreover, loss of STK4 expression showed a significant poor outcome in colon cancer patients by univariate and multivariate analysis. These results indicated that there is a positive correlation in STK4 expression and prognosis and survival of colon cancer patients. Loss of STK4 expression displayed poor outcome. The conclusion is that STK4 can be used as a prognostic maker to predict patient survival and play a role in metastasis suppression of colorectal cancer. Citation Format: Yu-Cheng Lee, Chia-Ning Yang, Tai-I Hsu, Pei-Jung Lu. STK4 downregulation promotes tumor invasion/migration and is associated with poor prognosis in human colon cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1146. doi:10.1158/1538-7445.AM2013-1146

Negative Regulation of Cell-proliferation of Adult Stem Cells in the Midgut and Hindgut by dMats in Drosophila melanogaster

The existence of adult stem cells in the midgut and hindgut of Drosophila has been reported. The components of Hippo pathway such as dWarts and dYki were involved in the regulation of stem cell proliferation in the midgut. In this study, we reported the role of dMats in the control of stem cell proliferation in the midgut and hindgut of adult fruit fly. The eGFP signals driven by dmats indicated that dMats expressed in small diploid cells in the adult midgut and hindgut. By inducing MARCM cell clones, the dmats -/-cell clones in the midgut exhibited a bigger cell number than wild type cell clones and tissue outgrowth. Similarly, the dmats-/- mutation also caused more cell numbers in hindgut. Thus, dMats was critical to control stem cell proliferation in midgut as well as in hindgut. Our results implicated an important regulatory role for Hippo pathway in the regulation of adult stem cell proliferation.