📋 Browse Articles

Acute lymphoblastic leukemia (ALL) has been a huge threat for people's health and finding effective target therapy is urgent and important. WWP2, as one of E3 ubiquitin ligase, is involved in many biological processes by specifically binding to substrates. PARP1 plays a role in cell apoptosis and is considered as a therapeutic target of certain cancers. In this study, we firstly found that WWP2 expressed higher in newly diagnosed ALL patients comparing with complete remission (CR) ALL patients and normal control people, and WWP2 in relapse ALL patients expressed higher than normal control people. WWP2 expression was related with the FAB subtype of ALL and the proportion of blast cells in bone marrow blood tested by flow cytometry. We demonstrated knockout WWP2 inhibited the ALL growth and enhanced apoptosis induced by Dox in vitro and vivo for the first time. WWP2 negatively regulated and interacted with PARP1 and WWP2 mechanically degraded PARP1 through polyubiquitin-proteasome pathway in ALL. These findings suggested WWP2 played a role in ALL development as well as growth and apoptosis, and also displayed a regulatory pathway of PARP1, which provided a new potential therapeutic target for the treatment of ALL. Show less

Dishvelled-2 (Dvl2) is an essential component of Wnt pathway, which controls several cell fate decisions during development, such as proliferation, survival and differentiation. Dvl2 forms higher-order protein assemblies in the cell that are critical for relaying the signal from upstream Wnt ligand-frizzled receptor binding to downstream effector β-catenin activation. However, the precise molecular nature and contribution of Dvl2 protein assemblies during Wnt signalling is unknown. Here, we show that Dvl2 forms protein condensates driven by liquid-liquid phase separation. An intrinsically disordered region (IDR) at the N-terminus is essential for Dvl2 phase separation. Importantly, we identified the HECT-E3 ligase WWP2 as an essential driver of Dvl2 phase separation in vitro and in cells. We demonstrated that ubiquitylation of Dvl2 through K63 linkage by WWP2 is required for formation of Dvl2 condensates. Phase-separated Dvl2 activates Wnt signaling by sequestering the components of destruction complex and thus relieving β-catenin. Together, our results reveal a ubiquitylation-dependent liquid-liquid phase separation as a new process through which Dvl2 forms condensates, which is necessary for transduction of Wnt signalling. This article has an associated First Person interview with the first author of the paper. Show less

Non-ischemic cardiomyopathy (NICM) can cause left ventricular dysfunction through interstitial fibrosis, which corresponds to the failure of cardiac tissue remodeling. Recent evidence implicates monocytes/macrophages in the etiopathology of cardiac fibrosis, but giving their heterogeneity and the antagonizing roles of macrophage subtypes in fibrosis, targeting these cells has been challenging. Here we focus on WWP2, an E3 ubiquitin ligase that acts as a positive genetic regulator of human and murine cardiac fibrosis, and show that myeloid specific deletion of WWP2 reduces cardiac fibrosis in hypertension-induced NICM. By using single cell RNA sequencing analysis of immune cells in the same model, we establish the functional heterogeneity of macrophages and define an early pro-fibrogenic phase of NICM that is driven by Ccl5-expressing Ly6c Show less

WW domain-containing E3 Ubiquitin-protein ligase 2 (WWP2) has been found to positively regulate odontoblastic differentiation by monoubiquitinating the transcription factor Kruppel-like factor 5 (KLF5) in a cell culture system. However, the in vivo role of WWP2 in mouse teeth remains unknown. To explore this, here we generated Wwp2 knockout (Wwp2 KO) mice. We found that molars in Wwp2 KO mice exhibited thinner dentin, widened predentin, and reduced numbers of dentinal tubules. In addition, expression of the odontoblast differentiation markers Dspp and Dmp1 was decreased in the odontoblast layers of Wwp2 KO mice. These findings demonstrate that WWP2 may facilitate odontoblast differentiation and dentinogenesis. Furthermore, we show for the first time that phosphatase and tensin homolog (PTEN), a tumor suppressor, is expressed in dental papilla cells and odontoblasts of mouse molars and acts as a negative regulator of odontoblastic differentiation. Further investigation indicated that PTEN is targeted by WWP2 for degradation during odontoblastic differentiation. We demonstrate PTEN physically interacts with and inhibits the transcriptional activity of KLF5 on Dspp and Dmp1. Finally, we found WWP2 was able to suppress the interaction between PTEN and KLF5, which diminished the inhibition effect of PTEN on KLF5. Taken together, this study confirms the essential role of WWP2 and the WWP2-PTEN-KLF5 signaling axis in odontoblast differentiation and dentinogenesis in vivo. Show less

The growth of antler is driven by endochondral ossification in the growth center of the apical region. Antler grows faster than cancer tissues, but it can be stably regulated and regenerated periodically. To elucidate the molecular mechanisms of how antler grows rapidly without carcinogenesis, in this study, we used RNA-seq technology to evaluate the changes of miRNA and mRNA profiles in antler at four different developmental stages, including 15, 60, 90, and 110 days. We identified a total of 55004 unigenes and 246 miRNAs of which, 10182, 13258, 10740 differentially expressed (DE) unigenes and 35, 53, 27 DE miRNAs were identified in 60-day vs. 15-day, 90-day vs. 60-day, and 110-day vs. 90-day. GO and KEGG pathway analysis indicated that DE unigenes and DE miRNA were mainly associated with chondrogenesis, osteogenesis and inhibition of oncogenesis, that were closely related to antler growth. The interaction networks of mRNA-mRNA and miRNA-mRNA related to chondrogenesis, osteogenesis and inhibition of oncogenesis of antler were constructed. The results indicated that mRNAs (COL2A1, SOX9, WWP2, FGFR1, SPARC, LOX, etc.) and miRNAs (miR-145, miR-199a-3p, miR-140, miR-199a-5p, etc.) might have key roles in chondrogenesis and osteogenesis of antler. As well as mRNA (TP53, Tpm3 and ATP1A1, etc.) and miRNA (miR-106a, miR-145, miR-1260b and miR-2898, etc.) might play important roles in inhibiting the carcinogenesis of antler. In summary, we constructed the mRNA-mRNA and miRNA-mRNA regulatory networks related to chondrogenesis, osteogenesis and inhibition of oncogenesis of antler, and identified key candidate mRNAs and miRNAs among them. Further developments and validations may provide a reference for in-depth analysis of the molecular mechanism of antler growth without carcinogenesis. Show less

Protein labeling strategies have been explored for decades to study protein structure, function, and regulation. Fluorescent labeling of a protein enables the study of protein-protein interactions through biophysical methods such as microscale thermophoresis (MST). MST measures the directed motion of a fluorescently labeled protein in response to microscopic temperature gradients, and the protein's thermal mobility can be used to determine binding affinity. However, the stoichiometry and site specificity of fluorescent labeling are hard to control, and heterogeneous labeling can generate inaccuracies in binding measurements. Here, we describe an easy-to-apply protocol for high-stoichiometric, site-specific labeling of a protein at its N-terminus with N-hydroxysuccinimide (NHS) esters as a means to measure protein-protein interaction affinity by MST. This protocol includes guidelines for NHS ester labeling, fluorescent-labeled protein purification, and MST measurement using a labeled protein. As an example of the entire workflow, we additionally provide a protocol for labeling a ubiquitin E3 enzyme and testing ubiquitin E2-E3 enzyme binding affinity. These methods are highly adaptable and can be extended for protein interaction studies in various biological and biochemical circumstances. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Labeling a protein of interest at its N-terminus with NHS esters through stepwise reaction Alternate Protocol: Labeling a protein of interest at its N-terminus with NHS esters through a one-pot reaction Basic Protocol 2: Purifying the N-terminal fluorescent-labeled protein and determining its concentration and labeling efficiency Basic Protocol 3: Using MST to determine the binding affinity of an N-terminal fluorescent-labeled protein to a binding partner. Basic Protocol 4: NHS ester labeling of ubiquitin E3 ligase WWP2 and measurement of the binding affinity between WWP2 and an E2 conjugating enzyme by the MST binding assay. Show less

Chronic elevated free fatty (FFA) levels are linked to metabolic disorders and tumorigenesis. However, the molecular mechanism by which FFAs induce cancer remains poorly understood. Here, we show that the tumor suppressor PTEN protein levels were decreased in high fat diet (HFD) fed mice. As palmitic acid (PA, C16:0) showed a significant increase in the HFD fed mice, we further investigated its role in PTEN down regulation. Our studies revealed that exposure of cells to high doses of PA induced mTOR/S6K-mediated phosphorylation of PTEN at T366. The phosphorylation subsequently enhanced the interaction of PTEN with the E3 ubiquitin ligase WW domain-containing protein 2 (WWP2), which promoted polyubiquitination of PTEN and protein degradation. Consistent with PTEN degradation, exposure of cells to increased concentrations of PA also promoted PTEN-mediated AKT activation and cell proliferation. Significantly, a higher level of S6K activation, PTEN T366 phosphorylation, and AKT activation were also observed in the livers of the HFD fed mice. These results provide a molecular mechanism by which a HFD and elevated PA regulate cell proliferation through inactivation of tumor suppressor PTEN. Show less

WW domain-containing E3 Ub-protein ligase 2 (WWP2) belongs to the homologous to E6AP C-terminus (HECT) E3 ligase family. It has been explored to regulate osteogenic differentiation, chondrogenesis, and palatogenesis. Odontoblasts are terminally differentiated mesenchymal cells, which contribute to dentin formation in tooth development. However, it remained unknown whether WWP2 participated in odontoblast differentiation. In this study, WWP2 was found to be expressed in mouse dental papilla cells (mDPCs), odontoblasts, and odontoblastic-induced mDPCs by immunohistochemistry and Western blotting. Besides, WWP2 expression was decreased in the cytoplasm but increased in the nuclei of differentiation-induced mDPCs. When Show less

Derivative chromosome der(1;16), isochromosome 1q, and deleted 16q-producing arm-level 1q-gain and/or 16q-loss-are recurrent cytogenetic abnormalities in breast cancer, but their exact role in determining the malignant phenotype is still largely unknown. We exploited The Cancer Genome Atlas (TCGA) data to generate and analyze groups of breast invasive carcinomas, called 1,16-chromogroups, that are characterized by a pattern of arm-level somatic copy number aberrations congruent with known cytogenetic aberrations of chromosome 1 and 16. Substantial differences were found among 1,16-chromogroups in terms of other chromosomal aberrations, aneuploidy scores, transcriptomic data, single-point mutations, histotypes, and molecular subtypes. Breast cancers with a co-occurrence of 1q-gain and 16q-loss can be distinguished in a "low aneuploidy score" group, congruent to der(1;16), and a "high aneuploidy score" group, congruent to the co-occurrence of isochromosome 1q and deleted 16q. Another three groups are formed by cancers showing separately 1q-gain or 16q-loss or no aberrations of 1q and 16q. Transcriptome comparisons among the 1,16-chromogroups, integrated with functional pathway analysis, suggested the cooperation of overexpressed 1q genes and underexpressed 16q genes in the genesis of both ductal and lobular carcinomas, thus highlighting the putative role of genes encoding gamma-secretase subunits (APH1A, PSEN2, and NCSTN) and Wnt enhanceosome components (BCL9 and PYGO2) in 1q, and the glycoprotein E-cadherin (CDH1), the E3 ubiquitin-protein ligase WWP2, the deubiquitinating enzyme CYLD, and the transcription factor CBFB in 16q. The analysis of 1,16-chromogroups is a strategy with far-reaching implications for the selection of cancer cell models and novel experimental therapies. Show less

The present work aimed to identify the roles of WWP2 (an E3 ubiquitin-protein ligase) and protein phosphatase 1 regulatory subunit 3A (PPP1R3A) in different pathological stages of cardiac arrhythmia development. Leptin-deficient mice (C57BLKS-Lepr Show less

Glioblastoma (GBM), a lethal primary brain tumor, contains glioma stem cells (GSCs) that promote malignant progression and therapeutic resistance. SOX2 is a core transcription factor that maintains the properties of stem cells, including GSCs, but mechanisms associated with posttranslational SOX2 regulation in GSCs remain elusive. Here, we report that DNA-dependent protein kinase (DNA-PK) governs SOX2 stability through phosphorylation, resulting in GSC maintenance. Mass spectrometric analyses of SOX2-binding proteins showed that DNA-PK interacted with SOX2 in GSCs. The DNA-PK catalytic subunit (DNA-PKcs) was preferentially expressed in GSCs compared to matched non-stem cell tumor cells (NSTCs) isolated from patient-derived GBM xenografts. DNA-PKcs phosphorylated human SOX2 at S251, which stabilized SOX2 by preventing WWP2-mediated ubiquitination, thus promoting GSC maintenance. We then demonstrated that when the nuclear DNA of GSCs either in vitro or in GBM xenografts in mice was damaged by irradiation or treatment with etoposide, the DNA-PK complex dissociated from SOX2, which then interacted with WWP2, leading to SOX2 degradation and GSC differentiation. These results suggest that DNA-PKcs-mediated phosphorylation of S251 was critical for SOX2 stabilization and GSC maintenance. Pharmacological inhibition of DNA-PKcs with the DNA-PKcs inhibitor NU7441 reduced GSC tumorsphere formation in vitro and impaired growth of intracranial human GBM xenografts in mice as well as sensitized the GBM xenografts to radiotherapy. Our findings suggest that DNA-PK maintains GSCs in a stem cell state and that DNA damage triggers GSC differentiation through precise regulation of SOX2 stability, highlighting that DNA-PKcs has potential as a therapeutic target in glioblastoma. Show less

Etomidate (ETO) is a commonly used intravenous anesthetic that has been reported to exert a tumor suppressive effect in several types of cancer. The present study aimed to investigate the effect of ETO on cell proliferation and apoptosis in non-small cell lung cancer (NSCLC) cells and elucidate its potential mechanism of action. Therefore, Cell Counting Kit-8 assay was performed to evaluate the effect of different concentrations of ETO (0, 1, 2 or 3 µg/ml) on A549 cell viability. In addition, the possible interaction between ETO and WW domain containing E3 ubiquitin protein ligase 2 (WWP2) was predicted using the STITCH database. Additionally, a stable WWP2-overexpressing A549 cell line was constructed by transfecting A549 cells with the pcDNA3.1-WWP2 plasmid. Cell proliferation and apoptosis were assessed using colony formation and TUNEL assays, respectively. The mRNA and protein expression levels of the apoptosis-related proteins Bcl-2, Bax, caspase 3 and cleaved-caspase 3 were determined by reverse transcription-quantitative PCR and western blotting. In addition, the expression and phosphorylation levels of proliferation-associated genes (PCNA and Ki-67) and proteins in the PI3K/Akt pathway were analyzed by western blotting. The results showed that treatment with ETO attenuated the cell viability and proliferation of A549 cells. ETO also promoted cell apoptosis and decreased the expression of the anti-apoptotic protein Bcl-2, whilst increasing that of pro-apoptotic proteins Bax and cleaved caspase 3 in a dose-dependent manner. Furthermore, ETO was found to negatively regulate the expression of WWP2, such that WWP2 overexpression reversed the potentiating effects of ETO on cell apoptosis. In addition, ETO promoted the expression of PTEN and reduced the phosphorylation levels of the PI3K/AKT pathway-related proteins. These effects aforementioned could also be reversed by WWP2 overexpression. Therefore, data from the present study suggest that ETO can attenuate the progression of NSCLC through by the PI3K/AKT pathway, specifically by targeting WWP2. These findings may provide a novel target for the treatment of NSCLC. Show less

The Salmonella enterica effector SteD depletes mature MHC class II (mMHCII) molecules from the surface of infected antigen-presenting cells through ubiquitination of the cytoplasmic tail of the mMHCII β chain. This requires the Nedd4 family HECT E3 ubiquitin ligase Wwp2 and a tumor-suppressing transmembrane protein adaptor Tmem127. Here, through a proteomic screen of dendritic cells, we found that SteD targets the plasma membrane protein CD97 for degradation by a similar mechanism. SteD enhanced ubiquitination of CD97 on K555 and mutation of this residue eliminated the effect of SteD on CD97 surface levels. We showed that CD97 localises to and stabilises the immunological synapse between dendritic cells and T cells. Removal of CD97 by SteD inhibited dendritic cell-T cell interactions and reduced T cell activation, independently of its effect on MHCII. Therefore, SteD suppresses T cell immunity by two distinct processes. Show less

Bortezomib-based chemotherapy represents the most prevalent regimens for multiple myeloma (MM), whereas acquired drug resistance remains a major obstacle. Myeloma cells often produce excessive amount of dickkopf-1 (DKK1), giving rise to myeloma bone disease. However, it remains obscure about the effects and mechanisms of DKK1 in the progression and bortezomib responsiveness of MM cells. In the current study, we found WWP2, an E3 ubiquitin-protein ligase, was downregulated in the bortezomib-resistant cells along with high expression of DKK1. Further investigation revealed that WWP2 was a direct target of Wnt/β-catenin signaling pathway, and DKK1 suppressed the expression of WWP2 via canonical Wnt signaling. We further identified that WWP2 mediated the ubiquitination and degradation of GLI2, a main transcriptional factor of the Hedgehog (Hh) pathway. Therefore, DKK1-induced WWP2 downregulation improved GLI2 stability and activation of Hh signaling pathway, contributing to the resistance to bortezomib of MM cells. Clinical data also validated that WWP2 expression was associated with the treatment response and clinic outcomes of MM patients. WWP2 overexpression restricted MM progression and enhanced cell sensitivity to bortezomib treatment in vitro and in vivo. Taken together, our findings demonstrate that DKK1 facilitates the generation of bortezomib resistance in MM via downregulating WWP2 and activating Hh pathway. Thus, the manipulation of DKK1-WWP2-GLI2 axis might sensitize myeloma cells to proteasome inhibitors. Show less

Poly(ADP-ribose) polymerase 1 (PARP1) has a major regulatory role in cardiovascular disease. However, inhibiting PARP1 activity does not significantly improve clinical outcomes of cardiovascular disease, which suggests that the regulatory mechanism of PARP1 in cardiovascular disease is unclear. Here, we focused on deacetylation regulatory mechanisms of PARP1 and crosstalk of PARP1 post-translational modifications. We uncovered the crucial molecular interactions and protein modifications of deacetylase Sirtuin 2 (SIRT2) and PARP1 in vascular damage. The results showed that SIRT2 was involved in this process and oxidative stress damage factor PARP1 was a novel physiological substrate of SIRT2. SIRT2 interacted with PARP1 at the PARP-A-helical domain and deacetylated the K249 residue of PARP1. Furthermore, SIRT2 promoted ubiquitination of the K249 residue of PARP1 via mobilization of the E3 ubiquitin ligase WW domain-containing protein 2 (WWP2), which led to proteasome-mediated degradation of PARP1. Knockout of SIRT2 in mice and cells increased PARP1 acetylation and decreased PARP1 ubiquitination, which in turn aggravated oxidative stress-induced vascular injury and remodeling. Conversely, overexpression of SIRT2 in mice and cells decreased PARP1 acetylation, increased PARP1 ubiquitination, and relieved oxidative stress-induced vascular injury and remodeling. Overall, this study revealed a previously unrecognized mechanistic link between SIRT2 and PARP1 in the regulation of oxidative stress-induced vascular injury. Show less

The pluripotency transcription factor SOX2 is essential for the maintenance of glioblastoma stem cells (GSC), which are thought to underlie tumor growth, treatment resistance, and recurrence. To understand how SOX2 is regulated in GSCs, we utilized a proteomic approach and identified the E3 ubiquitin ligase TRIM26 as a direct SOX2-interacting protein. Unexpectedly, we found TRIM26 depletion decreased SOX2 protein levels and increased SOX2 polyubiquitination in patient-derived GSCs, suggesting TRIM26 promotes SOX2 protein stability. Accordingly, TRIM26 knockdown disrupted the SOX2 gene network and inhibited both self-renewal capacity as well as in vivo tumorigenicity in multiple GSC lines. Mechanistically, we found TRIM26, via its C-terminal PRYSPRY domain, but independent of its RING domain, stabilizes SOX2 protein by directly inhibiting the interaction of SOX2 with WWP2, which we identify as a bona fide SOX2 E3 ligase in GSCs. Our work identifies E3 ligase competition as a critical mechanism of SOX2 regulation, with functional consequences for GSC identity and maintenance. Show less

High-throughput reliable data generation has become a substantial requirement in many "omics" investigations. In proteomics the sample preparation workflow consists of multiple steps adding more bias to the sample with each additional manual step. Especially for label-free quantification experiments, this drastically impedes reproducible quantification of proteins in replicates. Here, a positive pressure workstation was evaluated to increase automation of sample preparation and reduce workload as well as consumables. Digested peptide samples were purified utilizing a new semi-automated sample preparation device, the Resolvex A200, followed by nanospray liquid chromatography/electrospray ionization (nLC/ESI) Orbitrap tandem mass spectrometry (MS/MS) measurements. In addition, the sorbents Maestro and WWP2 (available in conventional cartridge and dual-chamber narrow-bore extraction columns) were compared with Sep-Pak C18 cartridges. Raw data was analyzed by MaxQuant and Perseus software. The semi-automated workflow with the Resolvex A200 workstation and both new sorbents produced highly reproducible results within 10-300 μg of peptide starting material. The new workflow performed equally as well as the routinely conducted manual workflow with similar technical variability in MS/MS-based identifications of peptides and proteins. A first application of the system to a biological question contributed to highly reliable results, where time-resolved proteomic data was separated by principal component analysis (PCA) and hierarchical clustering. The new workstation was successfully established for proteolytic peptide purification in our proteomic workflow without any drawbacks. Highly reproducible results were obtained in decreased time per sample, which will facilitate further large-scale proteomic investigations. Show less

BRCA1/BRCA2-containing complex subunit 3 (BRCC3) is a lysine 63-specific deubiquitinase involved in multiple biological processes, such as DNA repair and immune responses. However, the regulation mechanism for BRCC3 protein stability is still unknown. Here, we demonstrate that BRCC3 is mainly degraded through the ubiquitin-proteasome pathway. The HECT-type E3 ubiquitin ligase WWP2 modulates BRCC3 ubiquitination and degradation. ABRO1, a subunit of the BRCC36 isopeptidase complex (BRISC), competes with WWP2 to bind to BRCC3, thereby preventing WWP2-mediated BRCC3 ubiquitination and enhancing BRCC3 stability. Functionally, we show that lentivirus-mediated overexpression of WWP2 in murine macrophages inhibits NLRP3 inflammasome activation by decreasing BRCC3 protein level. This study provides the first insights into the regulation of BRCC3 stability and expands our knowledge about the physiological function of WWP2. Show less

The Salmonella enterica effector SteD depletes mature MHC class II (mMHCII) molecules from the surface of infected antigen-presenting cells through ubiquitination of the cytoplasmic tail of the mMHCII β chain. Here, through a genome-wide mutant screen of human antigen-presenting cells, we show that the NEDD4 family HECT E3 ubiquitin ligase WWP2 and a tumor-suppressing transmembrane protein of unknown biochemical function, TMEM127, are required for SteD-dependent ubiquitination of mMHCII. Although evidently not involved in normal regulation of mMHCII, TMEM127 was essential for SteD to suppress both mMHCII antigen presentation in mouse dendritic cells and MHCII-dependent CD4 Show less

WWP2 is a HECT-type E3 ubiquitin ligase that regulates various physiological and pathological activities by binding to different substrates, but its function and regulatory mechanism in vascular smooth muscle cells (VSMCs) are still unknown. Here, we clarified the role of WWP2 in the regulation of SIRT1-STAT3 and the impact of this regulatory process in VSMCs. We demonstrated that WWP2 expression was significantly increased in angiotensin II-induced VSMCs model. Knockdown of WWP2 significantly inhibited angiotensin II-induced VSMCs proliferation, migration and phenotypic transformation, whereas overexpression of WWP2 had opposite effects. In vivo experiments showed that vascular smooth muscle-specific WWP2 knockout mice significantly relieved angiotensin II-induced hypertensive angiopathy. Mechanistically, mass spectrometry and co-immunoprecipitation assays identified that WWP2 is a novel interacting protein of SIRT1 and STAT3. Moreover, WWP2 formed a complex with SIRT1-STAT3, inhibiting the interaction between SIRT1 and STAT3, then reducing the inhibitory effect of SIRT1 on STAT3, ensuing promoting STAT3-K685 acetylation and STAT3-Y705 phosphorylation in angiotensin II-induced VSMCs and mice. In conclusion, WWP2 modulates hypertensive angiopathy by regulating SIRT1-STAT3 and WWP2 suppression in VSMCs can alleviate hypertensive angiopathy vitro and vivo. These findings provide new insights into the treatment of hypertensive vascular diseases. Show less

It is critical to identify patients with stage II and III colorectal cancer (CRC) who will benefit from adjuvant chemotherapy (ACT) after curative surgery, while the only use of clinical factors is insufficient to predict this beneficial effect. In this study, we performed genetic algorithm (GA) to select ACT candidate genes, and built a predictive model of support vector machine (SVM) using gene expression profiles from the Gene Expression Omnibus database. The model contained four ACT candidate genes (EDEM1, MVD, SEMA5B, and WWP2) and TNM stage (stage II or III). After using Subpopulation Treatment Effect Pattern Plot to determine the optimal cutoff value of predictive scores, the validated patients from The Cancer Genome Atlas database can be divided into the predictive ACT-benefit/-futile groups. Patients in the predictive ACT-benefit group with 5-fluorouracil (5-Fu)-based ACT had significantly longer relapse-free survival (RFS) compared to those without ACT (P = .015); However, the difference in RFS in the predictive ACT-futile group was insignificant (P = .596). The multivariable analysis found that the predictive groups were significantly associated with the effect of ACT (P Show less

Oxidative stress-associated endothelial injury is the initial event and major cause of multiple cardiovascular diseases such as atherosclerosis and hypertensive angiopathy. A protein homeostasis imbalance is a critical cause of endothelial injury, and homologous to E6AP C-terminus (HECT)-type E3 ubiquitin ligases are the core factors controlling protein homeostasis. Although HECT-type E3 ubiquitin ligases are involved in the regulation of cardiac development and diseases, their roles in endothelial injury remain largely unknown. This study aimed to identify which HECT-type E3 ubiquitin ligase is involved in endothelial injury and clarify the mechanisms at molecular, cellular, and organism levels. We revealed a novel role of the HECT-type E3 ubiquitin ligase WWP2 in regulating endothelial injury and vascular remodeling after endothelial injury. Endothelial/myeloid-specific WWP2 knockout in mice significantly aggravated angiotensin II/oxidative stress-induced endothelial injury and vascular remodeling after endothelial injury. The same results were obtained from in vitro experiments. Mechanistically, the endothelial injury factor Septin4 was identified as a novel physiological substrate of WWP2. In addition, WWP2 interacted with the GTPase domain of Septin4, ubiquitinating Septin4-K174 to degrade Septin4 through the ubiquitin-proteasome system, which inhibited the Septin4-PARP1 endothelial damage complex. These results identified the first endothelial injury-associated physiological pathway regulated by HECT-type E3 ubiquitin ligases in vivo as well as a unique proteolytic mechanism through which WWP2 controls endothelial injury and vascular remodeling after endothelial injury. These findings might provide a novel treatment strategy for oxidative stress-associated atherosclerosis and hypertensive vascular diseases. Show less

This study investigates the antifibrotic activities and potential mechanisms of costunolide (COS), a natural sesquiterpene compound. Rats subjected to bile duct ligation and mice challenged with CCl In animals, COS administration attenuated hepatic histopathological injury and collagen accumulation and reduced the expression of fibrogenic genes. COS time- and dose-dependently suppressed the levels of fibrotic markers in LX-2 cells and mouse pHSCs. Mechanistic studies showed COS destabilized Notch3 and subsequently inhibited the Notch3-HES1 pathway, thus inhibiting HSC activation. Furthermore, COS blocked the WW domain-containing protein 2 (WWP2)/protein phosphatase 1G (PPM1G) interaction and enhanced the effect of WWP2 on Notch3 degradation. COS exerted potent antifibrotic effects in vitro and in vivo by disrupting the WWP2/PPM1G complex, promoting Notch3 degradation and inhibiting the Notch3/HES1 pathway. This indicates that COS may be a potential therapeutic candidate for the treatment of liver fibrosis. Show less

E3 ubiquitin ligase gene, WWP2, is associated with acute kidney injury (AKI). This research was conducted to explore the role of WWP2 in AKI. AKI cell model was produced in human renal proximal tubular epithelial cell line (HK-2) by ischemia-reperfusion (IR) injury. CCK8 and flow cytometry assay were performed to explore the influence of WWP2 overexpression on cell proliferation and apoptosis of IR-induced HK-2 cells. Quantitative real-time PCR and immunoblotting (IB) were performed to assess the gene and protein expression. Then, the influence of WWP2 on p53 ubiquitylation and degradation was estimated by immunoprecipitation assay. Our data indicated that WWP2 was down-regulated and p53 was up-regulated in IR-induced HK-2 cells. WWP2 overexpression promoted proliferation and inhibited apoptosis of IR-induced HK-2 cells. And WWP2 interacted with p53 and regulated p53 ubiquitylation and degradation. Furthermore, the influence of WWP2 on cell proliferation and apoptosis was rescued by MG132 (proteasome inhibitor) treatment. In conclusion, our work described for the first time the role of WWP2 in AKI, showing that WWP2 ameliorated AKI by mediating p53 ubiquitylation and degradation. Moreover, the study offers some important insights into the occurrence of AKI and WWP2 may be a novel target of AKI treatment. SIGNIFICANCE OF THE STUDY: Our data elaborates that WWP2 has protective effect against AKI by mediating p53 ubiquitylation and degradation. Thus, WWP2 might be a therapeutic target for AKI. Show less

The elevated expression of poly(ADP-ribose) polymerase-1 (PARP1) and increased PARP1 activity, namely, poly(ADP-ribosyl)ation (PARylation), have been observed in cardiac remodeling, leading to extreme energy consumption and myocardial damage. However, the mechanisms underlying the regulation of PARP1 require further study. WWP2, a HECT-type E3 ubiquitin ligase, is highly expressed in the heart, but its function there is largely unknown. Here, we clarified the role of WWP2 in the regulation of PARP1 and the impact of this regulatory process on cardiac remodeling. We determined that the knockout of WWP2 specifically in myocardium decreased the level of PARP1 ubiquitination and increased the effects of isoproterenol (ISO)-induced PARP1 and PARylation, in turn aggravating ISO-induced myocardial hypertrophy, heart failure, and myocardial fibrosis. Similar findings were obtained in a model of ISO-induced H9c2 cells with WWP2 knockdown, while the reexpression of WWP2 significantly increased PARP1 ubiquitination and decreased PAPR1 and PARylation levels. Mechanistically, coimmunoprecipitation results identified that WWP2 is a novel interacting protein of PARP1 and mainly interacts with its BRCT domain, thus mediating the degradation of PARP1 through the ubiquitin-proteasome system. In addition, lysine 418 (K418) and lysine 249 (K249) were shown to be of critical importance in regulating PARP1 ubiquitination and degradation by WWP2. These findings reveal a novel WWP2-PARP1 signal transduction pathway involved in controlling cardiac remodeling and may provide a basis for exploring new strategies for treating heart disorders related to cardiac remodeling. Show less

WW domain containing E3 Ub-protein ligase 2 (WWP2) plays an important role in tumor progression as an E3 ligase of PTEN. Here, we investigated the role of WWP2 in gastric cancer (GC). We found that WWP2 is overexpressed in GC tissues, which is closely related to poor prognosis of GC patients. Using a WWP2-shRNA lentivirus expressing system, we established WWP2 stable-knockdown GC cell lines and found that knockdown of WWP2 inhibits the proliferation of GC cells both in vitro and in vivo. Also, WWP2 silencing induced the up-regulation of PTEN protein level and down-regulation of AKT phosphorylation level. We further investigated the role of PTEN in this regulating process by performing rescue assay and found that PTEN is essential for WWP2-mediated regulation of GC cells proliferation. Taken together, our results demonstrated that WWP2 promotes proliferation of GC cells by downregulating PTEN, which may provide new therapeutic targets for GC. Show less

Alternative splicing within a gene can create different versions of an mRNA, called isoforms. CFIm, composed of a small subunit CFIm25 and two large subunits CFIm68 and CFIm59 (also known as CPSF7), has been proposed as an enhancer-dependent activator of mRNA 3' processing. In this study, we investigated the role of CPSF7 in hepatocellular carcinoma. Experimental evidence suggests that the expression level of CPSF7 is higher in liver cancer cells and tissues than in non-tumor hepatic cells and tissues. Furthermore, knockdown of CPSF7 effectively suppressed cell proliferation, migration and colony formation in liver cancer cells by inhibiting PTEN/AKT signaling. CPSF7 promoted WWP2-FL due to the presence of PTEN ubiquitination sites in this longer transcript. Taken together, we identified that CPSF7 regulates liver cancer growth by targeting WWP2-FL that in turn regulates AKT activation in a PTEN-dependent manner. Show less

Rho GTPase-activating proteins (RhoGAPs) have been reported to be of great importance in the initiation and development of many different cancers. However, their biological roles and regulatory mechanisms in lung cancer development and progression are poorly defined. Real-time PCR or western blotting analysis was used to detect Rho GTPase-activating protein 24 (ARHGAP24), WWP2, p27, p-STAT6 and STAT6 expression levels as well as the activity of RhoA and Rac1 in lung cancer. Cell proliferation, apoptosis and cell cycle were measured by CCK-8 and flow cytometry analysis. Tumor growth of lung cancer cells was measured using a nude mouse xenograft experiment model in vivo. The correlation between WWP2 and p27 was measured by co-immunoprecipitation and ubiquitination analysis. We found that ARHGAP24 expression was lower in lung cancer tissues collected from the The Cancer Genome Atlas and independent hospital database. Overexpression of ARHGAP24 significantly suppressed cell proliferation and the activity of RhoA and Rac1, induced cell apoptosis and arrested cell cycle at the G0-G1 phase. ARHGAP24 overexpression also inhibited tumor growth in nude mice, whereas knockdown of ARHGAP24 significantly promoted cell proliferation and WWP2 expression and inhibited cell cycle arrest at G1 phase through activating STAT6 signaling. ARHGAP24 overexpression inhibited WWP2 overexpression-induced cell proliferation, cell cycle progression and the decreased p27 expression. Moreover, WWP2 was found interacted with p27, and WWP2 overexpression promoted the ubiquitination of p27. In conclusion, our findings suggest that ARHGAP24 inhibits cell proliferation and cell cycle progression and induces cell apoptosis of lung cancer via a STAT6-WWP2-p27 axis. Show less