YAP promotes endothelial barrier repair by repressing STAT3/VEGF signaling

The Hippo Signaling Pathway Manipulates Cellular Senescence

The Hippo pathway, a kinase cascade, coordinates with many intracellular signals and mediates the regulation of the activities of various downstream transcription factors and their coactivators to maintain homeostasis. Therefore, the aberrant activation of the Hippo pathway and its associated molecules imposes significant stress on tissues and cells, leading to cancer, immune disorders, and a number of diseases. Cellular senescence, the mechanism by which cells counteract stress, prevents cells from unnecessary damage and leads to sustained cell cycle arrest. It acts as a powerful defense mechanism against normal organ development and aging-related diseases. On the other hand, the accumulation of senescent cells without their proper removal contributes to the development or worsening of cancer and age-related diseases. A correlation was recently reported between the Hippo pathway and cellular senescence, which preserves tissue homeostasis. This review is the first to describe the close relationship between aging and the Hippo pathway, and provides insights into the mechanisms of aging and the development of age-related diseases. In addition, it describes advanced findings that may lead to the development of tissue regeneration therapies and drugs targeting rejuvenation.

Naringenin alleviates intestinal ischemia/reperfusion injury by inhibiting ferroptosis via targeting YAP/STAT3 signaling axis

BACKGROUND

Intestinal ischemia/reperfusion injury (IRI) is a significant clinical emergency, and investigating novel therapeutic approaches and understanding their underlying mechanisms is essential for improving patient outcomes. Naringenin (Nar), a flavanone present in tomatoes and citrus fruits, is frequently consumed in the human diet and recognized for having immunomodulatory, anti-inflammatory, and antioxidant properties. Despite Nar being able to alleviate intestinal IRI, the exact molecular mechanisms remain elusive.

PURPOSE

To investigate Nar's protective properties on intestinal IRI and elucidate the mechanisms, a comprehensive approach that combines network pharmacology analysis with experimental verification in vitro and in vivo was adopted.

METHODS

The oxygen-glucose deprivation/reoxygenation (OGD/R) model in IEC-6 cells and a murine model of intestinal IRI were used. Nar's effects on intestinal IRI were assessed through histological analysis using H&E staining and tight junction (TJ) protein expression. Ferroptosis-related parameters, including iron levels, superoxide dismutase (SOD), glutathione (GSH), reactive oxygen species (ROS), malondialdehyde (MDA), and mitochondrial morphology, were analyzed. Network pharmacology was utilized to predict the pathways through which Nar exerts its anti-ferroptosis effects. Further mechanistic insights were obtained through si-RNA transfection, YAP inhibitor (verteporfin, VP) treatment, ferroptosis inhibitor (Ferrostatin-1) and ferroptosis inducer (Erastin) application, co-immunoprecipitation (Co-IP) and Western blotting.

RESULTS

Our results revealed that pretreatment with Nar significantly mitigated intestinal tissue damage and improved gut barrier function, as evidenced by increased TJ proteins (ZO-1 and Occludin). Nar reduced iron, MDA, and ROS, while it increased GSH and SOD levels. Additionally, Nar alleviated mitochondrial damage in mice. Nar treatment increased GPX4 and SLC7A11, while decreasing ACSL4 levels both in vivo and in vitro. Network pharmacology analysis suggested that Nar may target the Hippo signaling pathway. Notably, YAP, a key transcriptional co-activator within the Hippo pathway, was downregulated in intestinal IRI mice and OGD/R-induced IEC-6 cells. Nar pretreatment activated YAP, thereby augmenting anti-ferroptosis effects. The inhibition of YAP activation by VP or YAP knockdown increased p-STAT3 expression, thereby diminishing Nar's efficacy. Co-IP and immunofluorescence studies confirmed the interaction between YAP and STAT3.

CONCLUSION

This study shows that Nar can inhibit ferroptosis in intestinal IRI via activating YAP, which in turn suppresses STAT3 phosphorylation, thereby unveiling a novel mechanism and supporting Nar's potential to be a promising therapeutic agent for intestinal IRI.

BRAF Modulates the Interplay Between Cell-Cell and Cell-Extracellular Matrix Adhesions in PECAM-1-Mediated Mechanotransduction

Mechanotransduction, the process of how cells sense and convert mechanical stimuli into biochemical response, is crucial in the migration of leukocytes or cancer cells through the endothelium during inflammation or metastasis. Migrating cells exert forces on the endothelium through cell surface adhesion molecules, such as platelet endothelial adhesion molecule PECAM-1, and this is essential for a successful transmigration. To study PECAM-1-mediated mechanotransduction, we applied PECAM-1-antibody-coated magnetic beads and exerted about 40 pN force on the endothelial monolayer. We show that force increases cell-ECM adhesion in the cell center and is accompanied by the opening of cell-cell junctions. Upon depletion of the MEK/ERK kinase, BRAF force increases cell-ECM adhesion both at the cell periphery and in the cell center, but this does not result in the opening of cell-cell junctions. Decreasing cell-ECM adhesion in BRAF-depleted cells through FAK inhibition results in the remodeling of cell-cell junctions. Force-induced increase in cell-ECM adhesion in the cell center correlates with the activation of the transcriptional cofactor Yes-associated protein (YAP). Furthermore, the induced activation of YAP through LATS inhibition prevents junctional remodeling in control cells. Thus, the activation of YAP might determine the strength of cell-cell junctions during PECAM-1-mediated mechanotransduction.

Astragalus polysaccharide-containing 3D-printed scaffold for traumatized skin repair and proteomic study

Astragalus polysaccharide-containing 3D-printed scaffold shows great potential in traumatic skin repair. This study aimed to investigate its repairing effect and to combine it with proteomic technology to deeply resolve the related protein expression changes. Thirty SD rats were divided randomly into three groups (n = 10 per group): the sham-operated group, the model group and the scaffold group. Subsequently, we conducted a comparative analysis on trauma blood perfusion, trauma healing rate, histological changes, the expression of the YAP/TAZ signalling pathway and angiogenesis-related factors. Additionally, neonatal skin tissues were collected for proteomic analysis. The blood perfusion volume and wound healing recovery in the scaffold group were better than that in the model group (p < 0.05). The protein expression of STAT3, YAP, TAZ and expression of vascular-related factor A (VEGFA) in the scaffold group was higher than that in the model group (p < 0.05). Proteomic analysis showed that there were 207 differential proteins common to the three groups. Mitochondrial function, immune response, redox response, extracellular gap and ATP metabolic process were the main groups of differential protein changes. Oxidative phosphorylation, metabolic pathway, carbon metabolism, calcium signalling pathway, etc. were the main differential metabolic pathway change groups. Astragalus polysaccharide-containing 3D-printed scaffold had certain reversals of protein disorder. The Astragalus polysaccharide-containing 3D-printed scaffold may promote the VEGFs by activating the YAP/TAZ signalling pathway with the help of STAT3 into the nucleus, accelerating early angiogenesis of the trauma, correcting the protein disorder of the trauma and ultimately realizing the repair of the wound.

Effects of Angiogenic Factors on the Epithelial-to-Mesenchymal Transition and Their Impact on the Onset and Progression of Oral Squamous Cell Carcinoma: An Overview

High levels of vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF)-2 and angiopoietin (ANG)-2 are found in tissues from oral squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMDs). As might be expected, VEGF, FGF-2, and ANG-2 overexpression parallels the development of new blood and lymphatic vessels that nourish the growing OPMDs or OSCCs and provide the latter with metastatic routes. Notably, VEGF, FGF-2, and ANG-2 are also linked to the epithelial-to-mesenchymal transition (EMT), a trans-differentiation process that respectively promotes or exasperates the invasiveness of normal and neoplastic oral epithelial cells. Here, we have summarized published work regarding the impact that the interplay among VEGF, FGF-2, ANG-2, vessel generation, and EMT has on oral carcinogenesis. Results from the reviewed studies indicate that VEGF, FGF-2, and ANG-2 spark either protein kinase B (AKT) or mitogen-activated protein kinases (MAPK), two signaling pathways that can promote both EMT and new vessels' formation in OPMDs and OSCCs. Since EMT and vessel generation are key to the onset and progression of OSCC, as well as to its radio- and chemo-resistance, these data encourage including AKT or MAPK inhibitors and/or antiangiogenic drugs in the treatment of this malignancy.

HMGN5 Escorts Oncogenic STAT3 Signaling by Regulating the Chromatin Landscape in Breast Cancer Tumorigenesis

Cancer progression is highly dependent on the ability of cancer cell tumor formation, in which epigenetic modulation plays an essential role. However, the epigenetic factors promoting breast tumor formation are less known. Screened from three-dimensional (3D)-sphere tumor formation model, HMGN5 that regulates chromatin structures became the candidate therapeutic target in breast cancer, though its role is obscure. HMGN5 is highly expressed in 3D-spheres of breast cancer cells and clinical tumors, also an unfavorable prognostic marker in patients. Furthermore, HMGN5 controls tumor formation and metastasis of breast cancer cells in vitro and in vivo. Mechanistically, HMGN5 is governed by active STAT3 transcriptionally and further escorts STAT3 to shape the oncogenic chromatin landscape and transcriptional program. More importantly, interference of HMGN5 by nanovehicle-packaged siRNA effectively inhibits tumor growth in breast cancer cell-derived xenograft mice model.

IMPLICATIONS

Our findings reveal a novel feed-forward circuit between HMGN5 and STAT3 in promoting breast cancer tumorigenesis and suggest HMGN5 as a novel epigenetic therapeutic target in STAT3-hyperactive breast cancer.

The regulation of yes-associated protein/transcriptional coactivator with PDZ-binding motif and their roles in vascular endothelium

Normal endothelial function plays a pivotal role in maintaining cardiovascular homeostasis, while endothelial dysfunction causes the occurrence and development of cardiovascular diseases. Yes-associated protein (YAP) and its homolog transcriptional co-activator with PDZ-binding motif (TAZ) serve as crucial nuclear effectors in the Hippo signaling pathway, which are regulated by mechanical stress, extracellular matrix stiffness, drugs, and other factors. Increasing evidence supports that YAP/TAZ play an important role in the regulation of endothelial-related functions, including oxidative stress, inflammation, and angiogenesis. Herein, we systematically review the factors affecting YAP/TAZ, downstream target genes regulated by YAP/TAZ and the roles of YAP/TAZ in regulating endothelial functions, in order to provide novel potential targets and effective approaches to prevent and treat cardiovascular diseases.

Hippo: a new hub for atherosclerotic disease

Abstract:

Hippo,an evolutionarily conserved kinase cascade reaction in organisms,can respond to a set of signals,such as mechanical signals and cell metabolism,to maintain cell growth,differentiation,tissue/organ development and homeostasis.In the past ten years,HIPPO has controlled the development of tissues and organs by regulating the process of cell proliferation,especially in the field of cardiac regeneration after myocardial infarction.This suggests that HIPPO signaling is closely linked to cardiovascular disease.Atherosclerosis is the most common disease of the cardiovascular system. It is characterised by chronic inflammation of the vascular wall, mainly involving dysfunction of endothelial cells, smooth muscle cells and macrophages.Oxidized Low density lipoprotein (LDL) damages the barrier function of endothelial cells, which enter the middle membrane of the vascular wall, accelerates the formation of foam cells and promotes the occurrence and development of atherosclerosis.Autophagy is associated with the development of atherosclerosis.However, the mechanism of HIPPO regulation of atherosclerosis has not meant to clarified.In view of the pivotal role of this signaling pathway in maintaining cell growth,proliferation and differentiation,the imbalance of Hippo is related to atherosclerosis and related diseases.In this review,we emphasized Hippo as a hub for regulating atherosclerosis and discussed its potential targets in pathophysiology,human diseases,and related pharmacology.

Down-Regulated microRNA-192-5p Protects Against Hypoxic-Ischemic Brain Damage via Regulation of YAP1-Mediated Hippo Signaling Pathway

Hypoxic-ischemic brain damage (HIBD) is a familiar neurological disorder. Emerging reports manifest that microRNAs (miRs) are related to the progression of HIBD. The goal of this study is to explore the mechanism of miR-192-5p in HIBD via regulation of Yes-associated protein 1 (YAP1)-mediated Hippo signaling pathway. The miR-192-5p, YAP1, and Hippo pathway-related factors Phospho (p)-Triaminoguanidinium azide (TAZ) in hippocampal tissues and neurons were detected. The regulatory relationship between miR-192-5p and YAP1 was verified. Neonatal hypoxic ischemia and oxygen-glucose deprivation (OGD) were used to simulate HIBD in vivo and in vitro. The neurobehavioral impairment, neuronal damage and vascular endothelial growth factor (VEGF) expression of neonatal rats in each group were detected. The viability, apoptosis and VEGF expression of hippocampal neurons in each group were also examined. MiR-192-5p expression was elevated while YAP1 expression was reduced in hippocampal tissues of HIBD rats in vivo and OGD neurons in vitro. MiR-192-5p had a targeting relation with YAP1. Suppressed miR-192-5p or overexpressed YAP1 in HIBD rats alleviated neurobehavioral impairment and neuronal damage, and decreased the expression levels of p-TAZ and VEGF expression in vivo. Reduced miR-192-5p or augmented YAP1 decelerated the neuron apoptosis, decreased the p-TAZ level and VEGF level and promoted cell viability of OGD hippocampal neurons in vitro. The study highlights that inhibited miR-192-5p protects against HIBD via regulation of YAP1 and Hippo signaling pathway, which is beneficial for HIBD treatment.

Distinctive Roles of YAP and TAZ in Human Endothelial Progenitor Cells Growth and Functions

The hippo signaling pathway plays an essential role in controlling organ size and balancing tissue homeostasis. Its two main effectors, yes-associated protein (YAP) and WW domain-containing transcription regulator 1, WWTR1 or TAZ, have also been shown to regulate endothelial cell functions and angiogenesis. In this study, the functions of YAP and TAZ in human endothelial progenitor cells (EPCs) were investigated by a loss-of-function study using CRISPR/Cas9-mediated gene knockdown (KD). Depletion of either YAP or TAZ reduced EPC survival and impaired many of their critical functions, including migration, invasion, vessel-formation, and expression of pro-angiogenic genes. Notably, TAZ-KD EPCs exhibited more severe phenotypes in comparison to YAP-KD EPCs. Moreover, the conditioned medium derived from TAZ-KD EPCs reduced the survivability of human lung cancer cells and increased their sensitivity to chemotherapeutic agents. The overexpression of either wild-type or constitutively active TAZ rescued the impaired phenotypes of TAZ-KD EPCs and restored the expression of pro-angiogenic genes in those EPCs. In summary, we demonstrate the crucial role of Hippo signaling components, YAP and TAZ, in controlling several aspects of EPC functions that can potentially be used as a drug target to enhance EPC functions in patients.

YAP inhibition promotes endothelial cell differentiation from pluripotent stem cell through EC master transcription factor FLI1

Endothelial cells (ECs) derived from pluripotent stem cells (PSCs) provide great resource for vascular disease modeling and cell-based regeneration therapy. However, the molecular mechanisms of EC differentiation are not completely understood. In this study, we checked transcriptional profile by microarray and found Hippo pathway is changed and the activity of YAP decreased during mesoderm-mediated EC differentiation from human embryonic stem cells (hESCs). Knockdown of YAP in hESCs promoted both mesoderm and EC differentiation indicating by mesodermal- or EC-specific marker gene expression increased both in mRNA and protein level. In contrast, overexpression of YAP inhibited mesoderm and EC differentiation. Microarray data showed that several key transcription factors of EC differentiation, such as FLI1, ERG, SOX17 are upregulated. Interestingly, knockdown YAP enhanced the expression of these master transcription factors. Bioinformation analysis revealed that TEAD, a YAP binds transcription factors, might regulate the expression of EC master TFs, including FLI1. Luciferase assay confirmed that YAP binds to TEAD1, which would inhibit FLI1 expression. Finally, FLI1 overexpression rescued the effects of YAP overexpression-mediated inhibition of EC differentiation. In conclusion, we revealed the inhibitory effects of YAP on EC differentiation from PSCs, and YAP inhibition might promote expression of master TFs FLI1 for EC commitment through interacting with TEAD1, which might provide an idea for EC differentiation and vascular regeneration via manipulating YAP signaling.

Endothelial YAP/TAZ Signaling in Angiogenesis and Tumor Vasculature

Solid tumors are dependent on vascularization for their growth. The hypoxic, stiff, and pro-angiogenic tumor microenvironment induces angiogenesis, giving rise to an immature, proliferative, and permeable vasculature. The tumor vessels promote tumor metastasis and complicate delivery of anti-cancer therapies. In many types of tumors, YAP/TAZ activation is correlated with increased levels of angiogenesis. In addition, endothelial YAP/TAZ activation is important for the formation of new blood and lymphatic vessels during development. Oncogenic activation of YAP/TAZ in tumor cell growth and invasion has been studied in great detail, however the role of YAP/TAZ within the tumor endothelium remains insufficiently understood, which complicates therapeutic strategies aimed at targeting YAP/TAZ in cancer. Here, we overview the upstream signals from the tumor microenvironment that control endothelial YAP/TAZ activation and explore the role of their downstream targets in driving tumor angiogenesis. We further discuss the potential for anti-cancer treatments and vascular normalization strategies to improve tumor therapies.

Immuno-hippo: Research progress of the hippo pathway in autoimmune disease

Extensive research in Drosophila and mammals has identified the core components of Hippo signaling, which controls gene expression. Studies of Drosophila have demonstrated the highly conserved Hippo pathway controls tissue homeostasis and organ size by regulating the balance between cell proliferation and apoptosis. Recent work has indicated a potential role of the Hippo pathway in regulating the immune system, which is the key player in autoimmune disease (AID). Therefore, the Hippo pathway may become a novel target for curing AID. Although the pivotal role of both the Hippo pathway in tumorigenesis has been thoroughly investigated, the role of it in AID is still poorly understood. Elucidating the role of Hippo signaling pathways in the activation and expression of specific molecules involved in immune regulation is important for understanding the pathogenesis of AID and exploring novel therapeutic targets. To aid in further research, this review describes the relationship between the Hippo pathway and inflammatory signals such as NF-κB and JAK-STAT, the function of the Hippo pathway in the formation and differentiation of immune cells, and the regulatory role of the Hippo pathway in AID.