Yes-associated Protein Research Articles

Molecular pathology of small cell lung cancer: Overview from studies on neuroendocrine differentiation regulated by ASCL1 and Notch signaling.

Pulmonary neuroendocrine (NE) cells are rare airway epithelial cells. The balance between Achaete-scute complex homolog 1 (ASCL1) and hairy and enhancer of split 1, one of the target molecules of the Notch signaling pathway, is crucial for NE differentiation. Small cell lung cancer (SCLC) is a highly aggressive lung tumor, characterized by rapid cell proliferation, a high metastatic potential, and the acquisition of resistance to treatment. The subtypes of SCLC are defined by the expression status of NE cell-lineage transcription factors, such as ASCL1, which roles are supported by SRY-box 2, insulinoma-associated protein 1, NK2 homeobox 1, and wingless-related integration site signaling. This network reinforces NE differentiation and may induce the characteristic morphology and chemosensitivity of SCLC. Notch signaling mediates cell-fate decisions, resulting in an NE to non-NE fate switch. The suppression of NE differentiation may change the histological type of SCLC to a non-SCLC morphology. In SCLC with NE differentiation, Notch signaling is typically inactive and genetically or epigenetically regulated. However, Notch signaling may be activated after chemotherapy, and, in concert with Yes-associated protein signaling and RE1-silencing transcription factor, suppresses NE differentiation, producing intratumor heterogeneity and chemoresistance. Accumulated information on the molecular mechanisms of SCLC will contribute to further advances in the control of this recalcitrant cancer.

Human Nasal Inferior Turbinate-Derived Neural Stem Cells Improve the Niche of Substantia Nigra Par Compacta in a Parkinson's Disease Model by Modulating Hippo Signaling.

Parkinson's disease (PD) is one of the most prevalent neurodegenerative diseases, following Alzheimer's disease. The onset of PD is characterized by the loss of dopaminergic neurons in the substantia nigra. Stem cell therapy has great potential for the treatment of neurodegenerative diseases, and human nasal turbinate-derived stem cells (hNTSCs) have been found to share some characteristics with mesenchymal stem cells. Although the Hippo signaling pathway was originally thought to regulate cell size in organs, recent studies have shown that it can also control inflammation in neural cells. Dopaminergic neuron-like cells were differentiated from SH-SY5Y cells (DA-Like cells) and treated with 1-Methyl-4-phenylpyridinium iodide to stimulate Reactive oxidative species (ROS) production. A transwell assay was conducted to validate the effect of hNTSCs on the Hippo pathway. We generated an MPTP-induced PD mouse model and transplanted hNTSCs into the substantia nigra of PD mice via stereotaxic surgery. After five weeks of behavioral testing, the brain samples were validated by immunoblotting and immunostaining to confirm the niche control of hNTSCs. In-vitro experiments showed that hNTSCs significantly increased cell survival and exerted anti-inflammatory effects by controlling ROS-mediated ER stress and hippocampal signaling pathway factors. Similarly, the in-vivo experiments demonstrated an increase in anti-inflammatory effects and cell survival rate. After transplantation of hNTSCs, the PD mouse model showed improved mobility and relief from PD symptoms. hNTSCs improved the survival rate of dopaminergic neurons by manipulating the hippocampal pathway through Yes-associated protein (YAP)/transcriptional coactivator with a PDZ-binding motif (TAZ) by reducing inflammatory cytokines. In this study, we found that controlling the niche of hNTSCs had a therapeutic effect on PD lesions.

Silk Fibroin Films with Microscopic Surface Pattern as Promising Cartilage Tissue Engineering Scaffold in Supporting MSCs Amplification and Chondrogenic Differentiation

ABSTRACT Mesenchymal stem cells (MSCs) with multipotential differentiation ability are main cell source for cartilage tissue engineering, but its application is restricted by the difficulty in regulating committed chondrogenic differentiation. Study revealed that certain substrate topographic structure can enhance the chondrogenic differentiation of MSCs. This study prepared silk fibroin (SF) films with gradient microscopic surface patterns based on P280-P7000 type specification sandpapers, and investigated the adhesion, proliferation and chondrogenic differentiation of human adipose-derived stem cells (hADSCs) on the SF films. The results showed that the SF films surface had convex dots with diameter of 3–50 μm, and hADSCs could adhere and proliferate well on the film. Transcriptomics analysis indicated that hADSCs tend to differentiate differently on the SF films, among which hADSCs on P1000 SF films had higher expression of chondrogenic markers Sox-9 and Col-II, with activated yes associated protein (YAP) and restricted F-actin. In vitro co-culture of human OA knee cartilage with hADSCs seeded SF films found satisfactory cartilage protection effect in P1000 group. Overall, this study preliminarily revealed the microscopic surface pattern of SF films may induce chondrogenic differentiation of hADSCs through extracellular matrix mediated Hippo/Yap pathway, and provided a new strategy for cartilage repair.

Responses of osteoblasts under varied tensile stress types induced by stretching basement materials

ABSTRACT Osteoblasts are mechanosensitive cells. Tensile stress with different conditions, including loading time, frequency, magnitude, etc. would cause varied responses in osteoblasts. However, it was not clarified that the effect of the loading types on the osteoblasts. In this study, we focused on the effect of varied tensile stress types on osteoblasts, including isotropic stretch, biaxial stretch, and uniaxial stretch with the negative ratio of transverse strain to axial strain (NR) −1, 0, and 0.2 respectively. Cell proliferation was determined to be most efficient when stimulated by 6% strain at a frequency of 1 Hz and a negative value of 0 for 1 h/day. The varied strain resulted in a thickening of the F-actin cytoskeleton and a thinning of the nucleus. Nuclear flattening caused Yes-associated protein (YAP) to be transported to the nucleus. It was suggested that the influence of loading types on the mechanobiology responses must be noticed. The mechanism of cell mechanical sensitivity under varied loading types was explored, which would provide good suggestions for designing microstructures to control deformation patterns in bone tissue engineering.

BCAR4 facilitates trastuzumab resistance and EMT inbreast cancer via sponging miR-665 and interacting withYAP1.

Breast cancer antiestrogen resistance 4 (BCAR4) has been suggested that can modulate cell behavior, resulting in tumorigenesis and chemoresistance. However, the underlying mechanisms of BCAR4 in trastuzumab resistance (TR) is still elusive. Here, we explored the function and the underlying mechanism of BCAR4 involving in TR. We found that BCAR4 is significantly upregulated in trastuzumab-resistant BC cells. Knockdown of BCAR4 could sensitize the BC cells to trastuzumab and suppress epithelial-mesenchymal transition (EMT). Mechanically, BCAR4 promotes yes-associated protein 1 (YAP1) expression by competitively sponging miR-665, to activated TGF-β signaling. Reciprocally, YAP1 could occupy the BCAR4 promoter to enhance its transcription, suggesting that there exists a positive feedback regulation between YAP1 and BCAR4. Targeting the BCAR4/miR-665/YAP1 axis may provide a novel insight of therapeutic approaches for TR in BC.

Enhancing the productivity and proliferation of CHO-K1 cells by oncoprotein YAP (Yes-associated protein)

CHO cells are extensively employed in biological drug industry to manufacture therapeutic proteins. Nevertheless, production of biopharmaceuticals faces obstacles such as limited growth and inadequate productivity. Employing host cell engineering techniques for CHO cells serves as a valuable approach to address the constraints encountered in biologics manufacturing. Despite advancements, most techniques focus on specific genes to address individual cellular challenges. The significance of YAP, transcriptional co-activator, cannot be overstated due to its involvement in regulating organ size and tumor formation. YAP’s influence extends to various cellular processes and is regulated by kinase cascade in the Hippo pathway, which phosphorylates serine residues in specific LATS recognition motifs. Activation of YAP has been observed to impact both the size and quantity of cells. This research investigates the effects of YAP5SA on proliferation, apoptosis, and productivity in CHO-K1 cells. YAP5SA, with mutations in all five LATS-target sites, is selected for its heightened activity and resistance to repression through the Hippo-LATS1/2 kinase signaling pathway. Plasmid harboring YAP5SA was transfected into EPO-CHO and the influence of YAP5SA overexpression was investigated. According to our findings, transfection of EPO-CHO cells with YAP5SA exhibited a substantial enhancement in CHO cell productivity, resulting in a 3-fold increase in total protein and EPO, as well as a 1.5-fold increase in specific productivity. Additionally, it significantly contributes in augmenting viability, size, and proliferation. Overall, the findings of this study exemplify the potential of utilizing YAP5SA to impact particular cellular mechanisms, thereby presenting an avenue for customizing cells to fulfill production demands.Key points• YAP5SA in CHO cells boosts growth, reduces apoptosis, and significantly improves productivity.• YAP5SA regulates genes involved in proliferation, survival, and mTOR activation.• YAP5SA increases productivity by improving cell cycle, c-MYC expression, and mTOR pathway.

HMGB2 Release Promotes Pulmonary Hypertension and Predicts Severity and Mortality of Patients With Pulmonary Arterial Hypertension.

Pulmonary hypertension (PH) is a progressive and life-threatening disease characterized by pulmonary vascular remodeling, which involves aberrant proliferation and apoptosis resistance of the pulmonary arterial smooth muscle cells (PASMCs), resembling the hallmark characteristics of cancer. In cancer, the HMGB2 (high-mobility group box 2) protein promotes the pro-proliferative/antiapoptotic phenotype. However, the function of HMGB2 in PH remains uninvestigated. Smooth muscle cell (SMC)-specific HMGB2 knockout or HMGB2-OE (HMGB2 overexpression) mice and HMGB2 silenced rats were used to establish hypoxia+Su5416 (HySu)-induced PH mouse and monocrotaline-induced PH rat models, respectively. The effects of HMGB2 and its underlying mechanisms were subsequently elucidated using RNA-sequencing and cellular and molecular biology analyses. Serum HMGB2 levels were measured in the controls and patients with pulmonary arterial (PA) hypertension. HMGB2 expression was markedly increased in the PAs of patients with PA hypertension and PH rodent models and was predominantly localized in PASMCs. SMC-specific HMGB2 deficiency or silencing attenuated PH development and pulmonary vascular remodeling in hypoxia+Su5416-induced mice and monocrotaline-treated rats. SMC-specific HMGB2 overexpression aggravated hypoxia+Su5416-induced PH. HMGB2 knockdown inhibited PASMC proliferation in vitro in response to PDGF-BB (platelet-derived growth factor-BB). In contrast, HMGB2 protein stimulation caused the hyperproliferation of PASMCs. In addition, HMGB2 promoted PASMC proliferation and the development of PH by RAGE (receptor for advanced glycation end products)/FAK (focal adhesion kinase)-mediated Hippo/YAP (yes-associated protein) signaling suppression. Serum HMGB2 levels were significantly increased in patients with PA hypertension, and they correlated with disease severity, predicting worse survival. Our findings indicate that targeting HMGB2 might be a novel therapeutic strategy for treating PH. Serum HMGB2 levels could serve as a novel biomarker for diagnosing PA hypertension and determining its prognosis.

TSG-6 mediated extracellular matrix modifications regulate hypoxic-ischemic brain injury.

Proteoglycans containing link-domains modify the extracellular matrix (ECM) to regulate cellular homeostasis and can also sensitize tissues/organs to injury and stress. Hypoxic-Ischemic (H-I) injury disrupts cellular homeostasis by activating inflammation and attenuating regeneration and repair pathways. In the brain, the main component of the ECM is the glycosaminoglycan (GAG), Hyaluronic Acid (HA), but whether HA modifications of the ECM regulate cellular homeostasis and response to H-I injury is not known. In this report, employing both male and female mice, we demonstrate that link-domain containing proteoglycan, TNFα-stimulated gene-6 (TSG-6), is active in the brain from birth onwards and differentially modifies ECM HA during discrete neurodevelopmental windows. ECM HA modification by TSG-6 enables it to serve as a developmental switch to regulate activity of the Hippo pathway effector protein, Yes Associated Protein 1 (YAP1) in the maturing brain and in response to H-I injury. Mice that lack TSG-6 expression display dysregulated expression of YAP1 targets, excitatory amino acid transporter 1 (EAAT1; GLAST) and 2 (EAAT2; GLT-1). Dysregulation of YAP1 activation in TSG-6-/- mice coincides with age- and sex-dependent sensitization of the brain to H-I injury such that 1-week-old neonates display an anti-inflammatory response in contrast to an enhanced pro-inflammatory injury reaction in 3-month-old adult males but not females. Our findings thus support that a key regulator of age- and sex-dependent H-I injury response in the mouse brain is modulation of the Hippo-YAP1 pathway by TSG-6 dependent ECM modifications.Significance Statement Hypoxic-Ischemic (H-I) injury is a common cause of morbidity and mortality worldwide. Numerous genomic and proteomic screens have identified changes in extracellular matrix (ECM) as the most common finding, yet the downstream mechanistic insights remain obscure. We found that proteoglycan, TNF stimulated gene-6 (TSG-6) dependent ECM modifications regulate the activity of the Hippo pathway effector, the RNA transcription co-activator, Yes Associated Protein 1 (YAP1). Dysregulation of YAP1 activation in TSG-6-/- mice coincided with age- and sex-dependent sensitization of the brain to H-I injury such that neonates displayed an anti-inflammatory response in contrast to an enhanced pro-inflammatory injury reaction in adults. Thus, our findings establish TSG-6-dependent ECM modifications as a key regulator of age- and sex-dependent H-I injury responses.

Nuclear phosphoinositide signaling promotes YAP/TAZ-TEAD transcriptional activity in breast cancer.

The Hippo pathway effectors Yes-associated protein 1 (YAP) and its homolog TAZ are transcriptional coactivators that control gene expression by binding to TEA domain (TEAD) family transcription factors. The YAP/TAZ-TEAD complex is a key regulator of cancer-specific transcriptional programs, which promote tumor progression in diverse types of cancer, including breast cancer. Despite intensive efforts, the YAP/TAZ-TEAD complex in cancer has remained largely undruggable due to an incomplete mechanistic understanding. Here, we report that nuclear phosphoinositides function as cofactors that mediate the binding of YAP/TAZ to TEADs. The enzymatic products of phosphoinositide kinases PIPKIα and IPMK, including phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) and phosphatidylinositol 3,4,5-trisphosphate (P(I3,4,5)P3), bridge the binding of YAP/TAZ to TEAD. Inhibiting these kinases or the association of YAP/TAZ with PI(4,5)P2 and PI(3,4,5)P3 attenuates YAP/TAZ interaction with the TEADs, the expression of YAP/TAZ target genes, and breast cancer cell motility. Although we could not conclusively exclude the possibility that other enzymatic products of IPMK such as inositol phosphates play a role in the mechanism, our results point to a previously unrecognized role of nuclear phosphoinositide signaling in control of YAP/TAZ activity and implicate this pathway as a potential therapeutic target in YAP/TAZ-driven breast cancer.

Yes-associated protein regulates the differentiation and osteoporosis of bone marrow mesenchymal stem cells

Mammalian Yes-associated protein (YAP) is involved in the regulation of various biological behaviors. Osteoporosis (OP) is a common orthopedic disease. However, the role of YAP in the differentiation and osteoporosis of Bone marrow mesenchymal stem cells (BMSCs) is unclear. Ovariectomy (OVX)-induced OP rat model was constructed and YAP plasmid was transfected to detect bone density and alkaline phosphatase (ALP) activity. Rat BMSCs were assigned into 3 groups: sham group, OP group, and YAP group, in which YAP plasmid was transfected followed by analysis of YAP expression by real-time PCR. After 14 days of induction culture, type I collagen, Osterix and FABP4 mRNA expression was detected by real-time PCR along with Wnt5 protein expression by western blot and TGF-β secretion by ELISA. In OP rats, YAP expression was significantly down-regulated and the bone density and ALP activity decreased (P <0.05). YAP transfection in OP rats reversed the changes in OP rats. In OP group, YAP expression was decreased, and type I collagen and Osterix expression decreased, FABP4 expression increased, β-catenin expression and TGF-β secretion decreased (P <0.05). Transfection of YAP plasmid in BMSCs of OP group significantly reversed the above changes (P <0.05). In conclusion, YAP level decreases in OP and up-regulating its expression in BMSCs can promote osteogenic differentiation and inhibit adipogenic differentiation by regulating Tnt5/TGF-β signaling.

1231 Inhibition of YAP With Vertoporfin Makes Chordomas Sensitive to Radiation in Vitro and in Vivo: New Therapies to Combat Radioresistance

INTRODUCTION: Chordomas are locally invasive tumors of notochordal origin with a propensity to resist radiotherapy and with no FDA approved therapies. Verteporfin is a photosensitizer with the ability to inhibit the yes-associated-protein (YAP) pathway which is upregulated in chordomas and enables their resistance to radiotherapy. METHODS: We used five primary chordoma cell lines (JHC7, UCH1, UCH2, MUG-CHOR1, UM-CHOR1) to perform in vitro and in vivo experiments with 64 mice using a xenograft subcutaneous model of chordoma. We then knocked down the YAP gene in chordoma cells and performed experiments to confirm our results were secondary to verteporfin effects on YAP. RESULTS: Verteporfin has additive and synergistic effects on chordoma cells when combined with radiation. Chordoma cells treated with verteporfin have significantly more double-stranded DNA damage after radiation therapy (p < 0.0001) and verteporfin prevents repair of that DNA damage. Verteporfin significantly reduces DNA damage repair proteins and genes in chordoma cells (ATM: p = 0.0007, ATR: p < 0.0001, RADS1: p = 0.0033, BRCA1: p < 0.0001, BRCA2: p = 0.0012, PPP2R4: p < 0.0001). Verteporfin leads to significantly increased frequency of cells in G2/M phase (MUG-CHOR1: p < 0.0001, UCH2: p = 0.0021). We then performed all the above experiments using chordoma cells with the YAP gene knocked down and found that YAP knockdown led to enhanced radiation induced DNA damage (p<0.0001), diminished yH2AX response (p = 0.0264), and increased frequency of cells in G2/M phase (p < 0.0001). In vivo verteporfin treatment significantly inhibited chordoma tumor growth (p < 0.0001) and microparticles were most effective at radiosensitization. CONCLUSIONS: Inhibition of YAP using verteporfin radiosensitizes chordoma via 1) inhibition of the DNA damage repair cascade and 2) increasing frequency of the G2/M cell cycle phase when cells are most sensitive to radiation.

Nuclear curvature determines Yes-Associated Protein nuclear localization and differentiation of mesenchymal stem cells

Controlling mesenchymal stem cells (MSCs) differentiation remains a critical challenge in their therapeutic application. Numerous biophysical and mechanical stimuli influence stem cell fate, however, their relative efficacy and specificity in mechanically directed differentiation remain unclear. Yes-associated protein (YAP) is one key mechanosensitive protein that controls MSC differentiation. Previous studies have related nuclear mechanics with YAP activity, but we still lack an understanding of what nuclear deformation specifically regulates YAP, and its relationship with mechanical stimuli. Here we report that maximum nuclear curvature is the most precise biophysical determinant for YAP mechanotransduction mediated MSC differentiation, and is a relevant parameter for stem cell-based therapies. We employed traction force microscopy and confocal microscopy to characterize the causal relationships between contractility and nuclear deformation in regulating YAP activity in MSCs. We observed that an increase in contractility compresses nuclei anisotropically, where the degree of asymmetric compression increased the bending curvature of the nuclear membrane. We then examined membrane curvature and tension using thin micropatterned adhesive substrate lines and a FRET-based tension sensor, revealing the direct role of curvature in YAP activity driven by both active and passive nuclear import. Finally, we employed micropatterned lines to control nuclear curvature and precisely direct MSC differentiation. This work illustrates that nuclear curvature subsumes other biophysical aspects to control YAP-mediated differentiation in MSCs and may provide a deterministic solution to some of the challenges in mesenchymal stem cell therapies.

Fluid shear force and hydrostatic pressure jointly promote osteogenic differentiation of BMSCs by activating YAP1 and NFAT2.

Natural bone tissue features a complex mechanical environment, with cells responding to diverse mechanical stimuli, including fluid shear stress (FSS) and hydrostatic pressure (HP). However, current in vitro experiments commonly employ a singular mechanical stimulus to simulate the mechanical environment in vivo. The understanding of the combined effects and mechanisms of multiple mechanical stimuli remains limited. Hence, this study constructed a mechanical stimulation device capable of simultaneously applying FSS and HP to cells. This study investigated the impact of FSS and HP on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and examined the distinctions and interactions between the two mechanisms. The results demonstrated that both FSS and HP individually enhanced the osteogenic differentiation of BMSCs, with a more pronounced effect observed through their combined application. BMSCs responded to external FSS and HP stimulation through the integrin-cytoskeleton and Piezo1 ion channel respectively. This led to the activation of downstream biochemical signals, resulting in the dephosphorylation and nuclear translocation of the intracellular transcription factors Yes Associated Protein 1 (YAP1) and nuclear factor of activated T cells 2 (NFAT2). Activated YAP1 could bind to NFAT2 to enhance transcriptional activity, thereby promoting osteogenic differentiation of BMSCs more effectively. This study highlights the significance of composite mechanical stimulation in BMSCs' osteogenic differentiation, offering guidance for establishing a complex mechanical environment for in vitro functional bone tissue construction.

Cordycepin alleviates hepatic fibrosis in association with the inhibition of glutaminolysis to promote hepatic stellate cell senescence

Cordycepin (CRD) is an active component derived from Cordyceps militaris, which possesses multiple biological activities and uses in liver disease. However, whether CRD improves liver fibrosis by regulating hepatic stellate cell (HSC) activation has remained unknown. The study aims further to clarify the activities of CRD on liver fibrosis and elucidate the possible mechanism. Our results demonstrated that CRD significantly relieved hepatocyte injury and inhibited HSC activation, alleviating hepatic fibrogenesis in the Diethyl 1,4-dihydro-2,4,6-trimethyl-3,5-pyridinedicarboxylate (DDC)-induced mice model. In vitro, CRD exhibited dose-dependent repress effects on HSC proliferation, migration, and pro-fibrotic function in TGF-β1-activated LX-2 and JS-1 cells. The functional enrichment analysis of RNA-seq data indicated that the pathway through which CRD alleviates HSC activation involves cellular senescence and cell cycle-related pathways. Furthermore, it was observed that CRD accumulated the number of senescence-associated a-galactosidase positive cells and the levels of senescencemarker p21, and provoked S phasearrestof activated HSC. Remarkably, CRD treatment abolished TGF-β‐induced yes-associated protein (YAP) nuclear translocation that acts upstream of glutaminolysis in activated HSC. On the whole, CRD significantly inhibited glutaminolysis of activated-HSC and induced cell senescence through the YAP signaling pathway, consequently alleviating liver fibrosis, which may be a valuable supplement for treating liver fibrosis.

A LATS2/ALKBH5 positive feedback loop supports their oncogenic roles

N(6)-methyladenosine (m6A) critically regulates RNA dynamics in various biological processes. The m6A demethylase ALKBH5 promotes tumorigenesis of glioblastoma, while the intricate web that orchestrates its regulation remains enigmatic. Here, we discover that cell density affects ALKBH5 subcellular localization and m6A dynamics. Mechanistically, ALKBH5 is phosphorylated by the large tumor suppressor kinase 2 (LATS2), preventing its nuclear export and enhancing protein stability. Furthermore, phosphorylated ALKBH5 reciprocally erases m6A from LATS2 mRNA, thereby stabilizing this transcript. Unexpectedly, LATS2 depletion suppresses glioblastoma stem cell self-renewal independent of yes-associated protein activation. Additionally, deficiency in either LATS2 or ALKBH5 phosphorylation impedes tumor progression in mouse xenograft models. Moreover, high levels of LATS2 expression and ALKBH5 phosphorylation are associated with tumor malignancy in patients with gliomas. Collectively, our study unveils an oncogenic positive feedback loop between LATS2 and ALKBH5, revealing a non-canonical branch of the Hippo pathway for RNA processing and suggesting potential anti-cancer interventions.

Targeting ROCK2 improves macromolecular permeability in a 3D fibrotic pancreatic cancer microenvironment model

Pancreatic cancer is characterized by a densely fibrotic stroma. The fibrotic stroma hinders the intratumoral penetration of nanomedicine and diminishes therapeutic efficacy. Fibrosis is characterized by an abnormal organization of extracellular matrix (ECM) components, namely the abnormal deposition and/or orientation of collagen and fibronectin. Abnormal ECM organization is chiefly driven by pathological signaling in pancreatic stellate cells (PSCs), the main cell type involved in fibrogenesis. However, whether targeting signaling pathways involved in abnormal ECM organization improves the intratumoral penetration of nanomedicines is unknown. Here, we show that targeting transforming growth factor-β (TGFβ)/Rho-associated kinase (ROCK) 1/2 signaling in PSCs normalizes ECM organization and concomitantly improves macromolecular permeability of the fibrotic stroma. Using a 3-dimensional cell culture model of the fibrotic pancreatic cancer microenvironment, we found that pharmacological inhibition of TGFβ or ROCK1/2 improves the permeation of various macromolecules. By using an isoform-specific pharmacological inhibitor and siRNAs, we show that targeting ROCK2, but not ROCK1, alone is sufficient to normalize ECM organization and improve macromolecular permeability. Moreover, we found that ROCK2 inhibition/knockdown attenuates Yes-associated protein (YAP) nuclear localization in fibroblasts co-cultured with pancreatic cancer cells in 3D. Finally, pharmacological inhibition or siRNA-mediated knockdown of YAP normalized ECM organization and improved macromolecular permeability. Our results together suggest that the TGFβ/ROCK2/YAP signaling axis may be therapeutically targeted to normalize ECM organization and improve macromolecular permeability to augment therapeutic efficacy of nanomedicines in pancreatic cancer.

Combination of Molecule-Targeted Therapy and Photodynamic Therapy Using Nanoformulated Verteporfin for Effective Uveal Melanoma Treatment.

Uveal melanoma (UM) is the most common primary ocular malignancy in adults and has high mortality. Recurrence, metastasis, and therapeutic resistance are frequently observed in UM, but no beneficial systemic therapy is available, presenting an urgent need for developing effective therapeutic drugs. Verteporfin (VP) is a photosensitizer and a Yes-Associated Protein (YAP) inhibitor that has been used in clinical practice. However, VP's lack of tumor targetability, poor biocompatibility, and relatively low treatment efficacy hamper its application in UM management. Herein, we developed a biocompatible CD44-targeting hyaluronic acid nanoparticle (HANP) carrying VP (HANP/VP) to improve UM treatment efficacy. We found that HANP/VP showed a stronger inhibitory effect on cell proliferation than that of free VP in UM cells. Systemic delivery of HANP/VP led to targeted accumulation in the UM-tumor-bearing mouse model. Notably, HANP/VP mediated photodynamic therapy (PDT) significantly inhibited UM tumor growth after laser irradiation compared with no treatment or free VP treatment. Consistently, in HANP/VP treated tumors after laser irradiation, the tumor proliferation and YAP expression level were decreased, while the apoptotic tumor cell and CD8+ immune cell levels were elevated, contributing to effective tumor growth inhibition. Overall, the results of this preclinical study showed that HANP/VP is an effective nanomedicine for tumor treatment through PDT and inhibition of YAP in the UM tumor mouse model. Combining phototherapy and molecular-targeted therapy offers a promising approach for aggressive UM management.

USP40 promotes hepatocellular carcinoma progression through a YAP/USP40 positive feedback loop

Yes-associated protein (YAP) is an essential driver of hepatocellular carcinoma (HCC) progression and the ubiquitin-proteasome system controls its abundance. However, the role of ubiquitin-specific protease 40 (USP40) in YAP stability remains unclear. Here, USP40 was first identified as a novel regulator of YAP abundance and its target genes in HCC cells. USP40 interacted with YAP to remove the lysine 48 (K48)-linked polyubiquitination of YAP at K252 and K315 sites, thereby maintaining YAP stability. USP40 facilitated the proliferation, colony formation, migration and spheroid formation of HCC cells in vitro and promoted HCC growth in vivo in a YAP-dependent manner. In turn, YAP transcriptionally activated USP40 expression in HCC cells. RNA sequencing analysis showed that about 37% of USP40-regulated genes overlapped with YAP-regulated genes. Interestingly, stiffness-induced USP40 upregulation was abolished by YAP knockdown, and USP40 knockdown attenuated stiffness-induced YAP accumulation in HCC cells. Clinical data demonstrated that USP40 was positively associated with YAP expression in HCC tissues and its high expression indicated a poor prognosis. In conclusion, the USP40/YAP positive feedback loop contributes to HCC progression, suggesting that USP40 may be a promising drug target for anti-HCC.

Low-intensity pulsed ultrasound reduces alveolar bone resorption during orthodontic treatment via Lamin A/C-Yes-associated protein axis in stem cells.

The bone remodeling during orthodontic treatment for malocclusion often requires a long duration of around two to three years, which also may lead to some complications such as alveolar bone resorption or tooth root resorption. Low-intensity pulsed ultrasound (LIPUS), a noninvasive physical therapy, has been shown to promote bone fracture healing. It is also reported that LIPUS could reduce the duration of orthodontic treatment; however, how LIPUS regulates the bone metabolism during the orthodontic treatment process is still unclear. To investigate the effects of LIPUS on bone remodeling in an orthodontic tooth movement (OTM) model and explore the underlying mechanisms. A rat model of OTM was established, and alveolar bone remodeling and tooth movement rate were evaluated via micro-computed tomography and staining of tissue sections. In vitro, human bone marrow mesenchymal stem cells (hBMSCs) were isolated to detect their osteogenic differentiation potential under compression and LIPUS stimulation by quantitative reverse transcription-polymerase chain reaction, Western blot, alkaline phosphatase (ALP) staining, and Alizarin red staining. The expression of Yes-associated protein (YAP1), the actin cytoskeleton, and the Lamin A/C nucleoskeleton were detected with or without YAP1 small interfering RNA (siRNA) application via immunofluorescence. The force treatment inhibited the osteogenic differentiation potential of hBMSCs; moreover, the expression of osteogenesis markers, such as type 1 collagen (COL1), runt-related transcription factor 2, ALP, and osteocalcin (OCN), decreased. LIPUS could rescue the osteogenic differentiation of hBMSCs with increased expression of osteogenic marker inhibited by force. Mechanically, the expression of LaminA/C, F-actin, and YAP1 was downregulated after force treatment, which could be rescued by LIPUS. Moreover, the osteogenic differentiation of hBMSCs increased by LIPUS could be attenuated by YAP siRNA treatment. Consistently, LIPUS increased alveolar bone density and decreased vertical bone absorption in vivo. The decreased expression of COL1, OCN, and YAP1 on the compression side of the alveolar bone was partially rescued by LIPUS. LIPUS can accelerate tooth movement and reduce alveolar bone resorption by modulating the cytoskeleton-Lamin A/C-YAP axis, which may be a promising strategy to reduce the orthodontic treatment process.

Ischemia-inhibited ferric chelate reductase 1 improves ferroptosis-mediated intestinal ischemia injury via Hippo signaling

The precise mechanism of ferroptosis as a regulatory cell death in intestinal ischemia injury induced by vascular intestinal obstruction (Vio) remains to be elucidated. Here, we evaluated iron levels, glutathione peroxidase 4 (GPX4) and Acyl-CoA synthetase long-chain family member 4 (ACSL4) changes after intestinal ischemia injury to validate ferroptosis. As an enzyme for Fe3+ reduction to Fe2+, Ferric Chelate Reductase 1 (FRRS1) is involved in the electron transport chain and the tricarboxylic acid (TCA) cycle in mitochondria. However, whether it is involved in ferroptosis and its role in intestinal ischemia injury need to be clarified. In the present study, FRRS1 was overexpressed in vivo and in vitro. The results showed that overexpression of FRRS1 prevented ischemia-induced iron levels, reactive oxygen species (ROS) production, lipid peroxidation, inflammatory responses, and cell death. Meanwhile, FRRS1 overexpression promoted GPX4 expression and suppressed ACSL4 levels. Further studies revealed that FRRS1 overexpression inhibited the activity of large tumor suppressor 1 (LATS1) / Yes-associated protein (YAP) / transcriptional co-activator with PDZ-binding motif (TAZ), a key component of Hippo signaling. In conclusion, this study demonstrates that FRRS1 is intimately involved in the inhibition of ferroptosis and thus protection of the intestine from intestinal ischemia injury, its downstream mechanism was related to Hippo signaling. These data provide new sight for the prevention and treatment of intestinal ischemia injury.