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Background and aims: Liver regeneration retardation post partial hepatectomy (PH) is a common clinical problem after liver transplantation. Identification of key regulators in liver regeneration post PH may be beneficial for clinically improving the prognosis of patients after liver transplantation. This study aimed to clarify the function of junctional protein‐associated with coronary artery disease (JCAD) in liver regeneration post PH and to reveal the underlying mechanisms. Methods: JCAD knockout (JCAD‐KO), liver‐specific JCAD‐KO (Jcad△Hep) mice and their control group were subjected to 70% PH. RNA sequencing was conducted to unravel the related signalling pathways. Primary hepatocytes from KO mice were treated with epidermal growth factor (EGF) to evaluate DNA replication. Fluorescent ubiquitination‐based cell cycle indicator (FUCCI) live‐imaging system was used to visualise the phases of cell cycle. Results: Both global and liver‐specific JCAD deficiency postponed liver regeneration after PH as indicated by reduced gene expression of cell cycle transition and DNA replication. Prolonged retention in G1 phase and failure to transition over the cell cycle checkpoint in JCAD‐KO cell line was indicated by a FUCCI live‐imaging system as well as pharmacologic blockage. JCAD replenishment by adenovirus reversed the impaired DNA synthesis in JCAD‐KO primary hepatocyte in exposure to EGF, which was abrogated by a Yes‐associated protein (YAP) inhibitor, verteporfin. Mechanistically, JCAD competed with large tumour suppressor 2 (LATS2) for WWC1 interaction, leading to LATS2 inhibition and thereafter YAP activation, and enhanced expression of cell cycle‐associated genes. Conclusion: JCAD deficiency led to delayed regeneration after PH as a result of blockage in cell cycle progression through the Hippo–YAP signalling pathway. These findings uncovered novel functions of JCAD and suggested a potential strategy for improving graft growth and function post liver transplantation. Key Points: JCAD deficiency leads to an impaired liver growth after PH due to cell division blockage.JCAD competes with LATS2 for WWC1 interaction, resulting in LATS2 inhibition, YAP activation and enhanced expression of cell cycle‐associated genes.Delineation of JCADHippoYAP signalling pathway would facilitate to improve prognosis of acute liver failure and graft growth in living‐donor liver transplantation. [ABSTRACT FROM AUTHOR]

Background: Hepatocellular carcinoma (HCC) is most common malignant tumor worldwide, and one of the most lethal malignancies. MEX3A, RNA-binding protein, is profoundly implicated in tumor initiation and progression. But its role and potential mechanism in HCC remains fully unclear. Methods: The expression of MEX3A in HCC was analysis using the data derived from the Cancer Genome Atlas (TCGA) dataset and further confirmed by HCC samples and cells lines. The roles of MEX3A in the proliferation, migration and sorafenib resistance were detected both in vitro and vivo. In addition, the underline mechanism was investigated. Results: In this study, MEX3A expression was upregulated in HCC tissue and cell lines. Knockdown or overexpression of MEX3A disturbed the proliferation, migration and apoptosis of HCC cells by modulating the activation of Hippo signaling pathway. The expression of MEX3A was negatively associated with sorafenib sensitivity and upregulated in sorafenib resistant HCC cells. MEX3A knockdown facilitated the expression of WWC1, a negative modulator of Hippo signaling pathway, and led to increase of the phosphorylation of LATS1 and YAP1. Pharmacological inhibition of LATS1 or WWC1 overexpression alleviated the proliferative and migrated suppression and increased sorafenib sensitivity, whereas WWC1 inhibition using genetic interference strategy showed opposite trend in MEX3A knockdown HCC cells. Importantly, MEX3A knockdown led to growth and lung metastasis inhibition using xenograft model established by means of subcutaneous or tail vein injection. In addition, a combination of MEX3A knockdown and WWC1 overexpression dramatically enhances the growth inhibition of sorafenib in vivo. Conclusion: MEX3A may facilitate HCC progression and hinder sorafenib sensitivity via inactivating Hippo signaling. The present study suggested that targeting MEX3A can be served as a novel therapeutic strategy for HCC. [ABSTRACT FROM AUTHOR]

Objective: It is suggested that WWC1 has an active role in melanoma progression. Therefore, it was aimed to evaluate the WWC1 gene expression profiles in melanoma, an aggressive malignant skin tumor. Materials and Methods: Quantitative data from melanoma samples (n=592) were clinically evaluated using cBioPortal. Gene expression (GSE65904 and GSE22155) and gene methylation datasets (GSE120878) were retrieved from the Gene Expression Omnibus (GEO) database. Using the GeneMANIA database, the functions of given genes and pathways were evaluated. The STRING database achieved a protein-protein interaction (PPI) network was used to visualize it. Results: Mutations in the WWC1 were found in 6.7% of all melanoma samples, 8% of skin cutaneous melanoma, and 2.8% of metastatic melanoma. When the GeneMANIA platform was used to analyze gene interactions, it was determined that the WWC1 gene shared common protein domains with three genes, was co-expressed with five genes, and interacted with 17 other genes. According to the function analysis results, the most effective of the ten functions of WWC1 was Hippo signaling, with a coverage value of 0.16 (p=0.009). In addition, it then played a role in Notch signaling and organ growth. When the protein-protein interactions were examined, it was determined that it interacted with ten proteins and was co-expressed with nine. Conclusion: The findings demonstrated the potential of WWC1 to be effective in the progression of melanoma. Further research is needed to provide a more accurate analysis of WWC1 expression and methylation. [ABSTRACT FROM AUTHOR]

Abstract Sepsis is characterized by a severe inflammatory response throughout the whole body and can induce acute kidney injury (AKI). This research aimed to investigate the regulatory mechanisms underlying miR‐155‐5p in sepsis‐induced AKI. CLP‐treated mice were used as an in vivo model of sepsis‐induced AKI, and LPS‐treated HK‐2 and TCMK‐1 cells were used as in vitro models. Bioinformatics analyses and mechanistic assays were utilized to reveal the relationships between molecules. H&E staining was used to reveal morphological changes in kidney tissues. ELISAs were conducted to detect the concentrations of proinflammatory cytokines. We discovered that miR‐155‐5p was prominently upregulated in sepsis‐induced AKI in vivo and in vitro. MiR‐155‐5p inhibition alleviated kidney injury in mice. Moreover, WWC1 served as a direct target of miR‐155‐5p and was negatively regulated by miR‐155‐5p. WWC1 upregulation inhibited the productions of inflammatory cytokines and suppressed apoptosis in vivo and in vitro. In addition, rescue assays demonstrated that WWC1 knockdown counteracted the inhibitory effect of anti‐miR‐155‐5p on inflammation and apoptosis. Moreover, miR‐155‐5p could bind to XIST. XIST expression was downregulated in LPS‐stimulated HK‐2 and TCMK‐1 cells. XIST could negatively regulate miR‐155‐5p expression and positively regulate WWC1 expression. Rescue assays revealed that miR‐155‐5p overexpression significantly reversed the suppressive effects of XIST upregulation on inflammation and apoptosis. In conclusion, our study revealed that the XIST/miR‐155‐5p/WWC1 axis modulated sepsis‐induced AKI progression, providing promising insight into therapeutic targets for sepsis‐induced AKI.

Mutations of human TBC1D24 are associated with deafness, epilepsy, or DOORS syndrome (deafness, onychodystrophy, osteodystrophy, cognitive disability, and seizures). The causal relationships between TBC1D24 variants and the different clinical phenotypes are not understood. Our hypothesis is that phenotypic heterogeneity of missense mutations of TBC1D24 results, in part, from perturbed binding of different protein partners. To discover novel protein partners of TBC1D24, we conducted yeast two-hybrid (Y2H) screen using mouse full-length TBC1D24 as bait. Kidney and brain protein (KIBRA), a scaffold protein encoded by Wwc1, was identified as a partner of TBC1D24. KIBRA functions in the Hippo signaling pathway and is important for human cognition and memory. The TBC1D24 TLDc domain binds to KIBRA full-length and to its C2 domain, confirmed by Y2H assays. No interaction was detected with Y2H assays between the KIBRA C2 domain and TLDc domains of NCOA7, MEAK7, and OXR1. Moreover, the C2 domains of other WWC family proteins do not interact with the TLDc domain of TBC1D24, demonstrating specificity. The mRNAs encoding TBC1D24 and KIBRA proteins in mouse are coexpressed at least in a subset of hippocampal cells indicating availability to interact in vivo. As two epilepsy-associated recessive variants (Gly511Arg and Ala515Val) in the TLDc domain of human TBC1D24 disrupt the interaction with the human KIBRA C2 domain, this study reveals a pathogenic mechanism of TBC1D24-associated epilepsy, linking the TBC1D24 and KIBRA pathways. The interaction of TBC1D24-KIBRA is physiologically meaningful and necessary to reduce the risk of epilepsy., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Published by Elsevier Inc.)

Sepsis is characterized by a severe inflammatory response throughout the whole body and can induce acute kidney injury (AKI). This research aimed to investigate the regulatory mechanisms underlying miR‐155‐5p in sepsis‐induced AKI. CLP‐treated mice were used as an in vivo model of sepsis‐induced AKI, and LPS‐treated HK‐2 and TCMK‐1 cells were used as in vitro models. Bioinformatics analyses and mechanistic assays were utilized to reveal the relationships between molecules. H&E staining was used to reveal morphological changes in kidney tissues. ELISAs were conducted to detect the concentrations of proinflammatory cytokines. We discovered that miR‐155‐5p was prominently upregulated in sepsis‐induced AKI in vivo and in vitro. MiR‐155‐5p inhibition alleviated kidney injury in mice. Moreover, WWC1 served as a direct target of miR‐155‐5p and was negatively regulated by miR‐155‐5p. WWC1 upregulation inhibited the productions of inflammatory cytokines and suppressed apoptosis in vivo and in vitro. In addition, rescue assays demonstrated that WWC1 knockdown counteracted the inhibitory effect of anti‐miR‐155‐5p on inflammation and apoptosis. Moreover, miR‐155‐5p could bind to XIST. XIST expression was downregulated in LPS‐stimulated HK‐2 and TCMK‐1 cells. XIST could negatively regulate miR‐155‐5p expression and positively regulate WWC1 expression. Rescue assays revealed that miR‐155‐5p overexpression significantly reversed the suppressive effects of XIST upregulation on inflammation and apoptosis. In conclusion, our study revealed that the XIST/miR‐155‐5p/WWC1 axis modulated sepsis‐induced AKI progression, providing promising insight into therapeutic targets for sepsis‐induced AKI. [ABSTRACT FROM AUTHOR]

Abstract Whether SOX2 and ACTL6A/TP63 interact with the Hippo‐YAP1 pathway in esophageal squamous cell carcinoma (ESCC) remains unclear. Here, we reveal that SOX2, ACTL6A, and TP63 are co‐amplified and upregulated in ESCC samples. Multiple SOX2 binding peaks in the locus of WWC1, a Hippo‐YAP1 regulator, and an inverse correlation between the expression of SOX2 and WWC1 are identified, suggesting direct repression of WWC1 by SOX2. Expression scores of SOX2 are higher in tumors than normal tissues and positively correlated with nuclear YAP1 staining in primary ESCC. Moreover, SOX2 gain‐of‐function significantly promotes nuclear YAP1 expression in ESCC cells while silencing of SOX2 expression inhibits YAP1 activation. SOX2 overexpression leads to a significant enhancement of cell migration and invasion as well as chemoresistance to cisplatin, whereas knockdown of SOX2 or ectopic expression of WWC1 suppresses the SOX2‐induced migration ability and invasive potential. Disruption of this SOX2‐WWC1‐YAP1 axis could be a therapeutic strategy for SOX2‐dependent tumors.

The WW and C2 domain containing 1 (WWC1) gene encodes a protein named WWC1 (or KIBRA), which is involved in the Hippo signaling pathway. WWC1 is often lost in triple‐negative breast cancer and has been shown to suppress tumor metastasis. In this study, 470 breast cancer patients were recruited and WWC1 expression in the tumor samples was measured with quantitative reverse transcriptase PCR. Associations of WWC1 expression with breast cancer survival were analyzed using the Cox proportional hazards regression model and Kaplan–Meier survival analysis. The relationship between WWC1 expression and methylation was evaluated in a dataset from The Cancer Genome Atlas. Using our microarray data on gene expression and the Ingenuity Pathway Analysis, we predicted the WWC1‐associated signaling pathways in breast cancer. Our results showed that low expression of WWC1 was significantly associated with advanced‐stage diseases, high‐grade tumors, and estrogen receptor‐ or progesterone receptor‐negative status. Compared to those with high expression, patients with low WWC1 had higher risk of breast cancer relapse [hazard ratio (HR) = 2.06, 95% confidence interval (CI): 1.26–3.37] and higher risk of death (HR = 2.76, 95% CI: 1.51–5.03). The association with relapse‐free survival remained significant after adjustment for disease stage, tumor grade, and hormone receptor status and was replicated in a public dataset. Analysis of high‐throughput gene expression data indicated that WWC1 was involved in the Hippo signaling pathway. Online data also suggested that DNA methylation was inversely associated with WWC1 expression. The study confirmed that low WWC1 expression was associated with aggressive breast cancer and poor survival outcomes.

BackgroundWe investigated the prognostic effects and their patterns of immune infiltration of hippo pathway core genes in lung squamous cell carcinoma, in order to find some clues for underlying mechanisms of LUSC tumorigenesis and help developing new therapeutic methods.MethodsThe mutational data, transcriptome data and corresponding clinical medical information of LUSC patients were extracted from The Cancer Genome Atlas (TCGA) database. Differential expression genes (DEGs) and Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were explored. Survival analysis for the hippo core genes and the prognostic model were performed. Immune infiltration was estimated by CIBERSORT algorithm and some immune checkpoints-related genes were further investigated.ResultsOverall, 551 LUSC samples were included in our study, consisting of 502 LUSC tumor samples and 49 adjacent normal samples, respectively. There were 1910 up-regulated DEGs and 2253 down-regulated DEGs were finally identified. The top five mutational hippo pathway core genes were LATS1 (4%), WWC1 (2%), TAOK1 (2%), TAOK3 (2%), and TAOK2 (2%), respectively. the mutation of LATS2 was highly associated with co-mutational NF2 (P

Background: We investigated the prognostic effects and their patterns of immune infiltration of hippo pathway core genes in lung squamous cell carcinoma, in order to find some clues for underlying mechanisms of LUSC tumorigenesis and help developing new therapeutic methods. Methods: The mutational data, transcriptome data and corresponding clinical medical information of LUSC patients were extracted from The Cancer Genome Atlas (TCGA) database. Differential expression genes (DEGs) and Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were explored. Survival analysis for the hippo core genes and the prognostic model were performed. Immune infiltration was estimated by CIBERSORT algorithm and some immune checkpoints-related genes were further investigated. Results: Overall, 551 LUSC samples were included in our study, consisting of 502 LUSC tumor samples and 49 adjacent normal samples, respectively. There were 1910 up-regulated DEGs and 2253 down-regulated DEGs were finally identified. The top five mutational hippo pathway core genes were LATS1 (4%), WWC1 (2%), TAOK1 (2%), TAOK3 (2%), and TAOK2 (2%), respectively. the mutation of LATS2 was highly associated with co-mutational NF2 (P <0.05) and TAOK1 (P <0.05). In survival analyses, we found only WWC1 (log-rank p = 0.046, HR = 1.32, 95% CI = 1–1.73) and LATS2 (log-rank p = 0.013, HR = 1.41, 95%CI = 1.08–1.86) had significant prognostic roles. After getting the three subgroups according to the subtyping results, we demonstrated that T cell gamma delta (p = 5.78e-6), B cell memory (p = 4.61e-4) and T cell CD4+ memory resting (p = 2.65e-5) had significant differences among the three groups. SIGLEC15 (P <0.01) and CD274 (P <0.05) also had statistical differences among the three subgroups. Conclusions: Our study verified the prognostic roles of WWC1 and LATS2 in LUSC patients. Immune checkpoints-related genes SIGLEC15 and CD274 had statistical differences among the three subgroups, which may provide new perceptions on the molecular mechanisms in LUSC and maybe helpful for precisely selecting specific LUSC patients with potential immunotherapy benefits. [ABSTRACT FROM AUTHOR]

Hyperuricemia (HUA) is a metabolic disorder characterized by elevated serum uric acid (UA), primarily attributed to the hepatic overproduction and renal underexcretion of UA. Despite the elucidation of molecular pathways associated with this underexcretion, the etiology of HUA remains largely unknown. In our study, using by Uox knockout rats, HUA mouse, and cell line models, we discovered that the increased WWC1 levels were associated with decreased renal UA excretion. Additionally, using knockdown and overexpression approaches, we found that WWC1 inhibited UA excretion in renal tubular epithelial cells. Mechanistically, WWC1 activated the Hippo pathway, leading to phosphorylation and subsequent degradation of the downstream transcription factor YAP1, thereby impairing the ABCG2 and OAT3 expression through transcriptional regulation. Consequently, this reduction led to a decrease in UA excretion in renal tubular epithelial cells. In conclusion, our study has elucidated the role of upregulated WWC1 in renal tubular epithelial cells inhibiting the excretion of UA in the kidneys and causing HUA., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The Hippo pathway participates in development of numerous tumors through regulating tissue growth and cell fate. This study aimed to detect the association between the genetic variants in Hippo pathway genes and bladder cancer risk in a Chinese population. A case–control study of 580 cases and 1101 controls was performed to evaluate the association of single nucleotide polymorphisms (SNPs) in 39 candidate genes involved in the Hippo pathway with bladder cancer risk. A logistic regression model was used to assess the effects of SNPs on bladder cancer susceptibility. Candidate gene expression in human bladder cancer samples was detected using The Cancer Genome Atlas (TCGA) database and the Gene Expression Omnibus (GEO) datasets. We found that SNP rs755813 in WWC1 was significantly associated with a decreased risk of bladder cancer [odds ratio (OR) = 0.76, 95% confidence interval (CI) = 0.66–0.88, P = 3.63 × 10–4], which was more common in patients with low grade and non-muscle invasive tumors. Younger subjects (age ≤ 65) (OR = 0.70, 95% CI = 0.56–0.86), females (0.35, 0.23–0.52) and non-smokers (0.72, 0.58–0.88) showed a pronounced association between the rs755813 C allele and risk of bladder cancer by stratified analysis. The WWC1 was upregulated in bladder cancer tissues according to TCGA and GEO datasets. These findings indicated that genetic variant of WWC1 gene in Hippo signaling pathway contributes to the decreased risk of bladder cancer in the Chinese population and may have the protective effect against the development of bladder cancer. [ABSTRACT FROM AUTHOR]

Abstract Background KIBRA has been suggested as a key regulator of the Hippo signaling pathway, regulating organ size, cell contact inhibition, tissue regeneration as well as tumorigenesis and cystogenesis. We recently reported that human KIBRA expression depends on a complex alternative CpG-rich promoter system. Our current study aimed at the identification of epigenetic mechanisms associated with alterations in KIBRA expression regulation. Results We identified two separated methylation-sensitive CpG islands located to independent KIBRA promoter regions. In vitro promoter methylation analysis using human neuroblastoma (SH-SY5Y) and immortalized kidney cells (IHKE) revealed that total promoter methylation by CpG methyltransferase SssI resulted in complete abrogation of transcriptional activity (p

Osteoarthritis (OA) is an age-related or post-traumatic degenerative whole joint disease characterized by the rupture of articular cartilage homeostasis, the regulatory mechanisms of which remain elusive. This study identifies the essential role of heterogeneous nuclear ribonucleoprotein K (hnRNPK) in maintaining articular cartilage homeostasis. Hnrnpk expression is markedly downregulated in human and mice OA cartilage. The deletion of Hnrnpk effectively accelerates the development of post-traumatic and age-dependent OA in mice. Mechanistically, the KH1 and KH2 domain of Hnrnpk bind and degrade the mRNA of WWC1. Hnrnpk deletion increases WWC1 expression, which in turn leads to the activation of Hippo signaling and ultimately aggravates OA. In particular, intra-articular injection of LPA and adeno-associated virus serotype 5 expressing WWC1 RNA interference ameliorates cartilage degeneration induced by Hnrnpk deletion, and intra-articular injection of adeno-associated virus serotype 5 expressing Hnrnpk protects against OA. Collectively, this study reveals the critical roles of Hnrnpk in inhibiting OA development through WWC1-dependent downregulation of Hippo signaling in chondrocytes and defines a potential target for the prevention and treatment of OA., Competing Interests: Declaration of interests The authors declare no competing interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

OBJECTIVE: The aim of this study was to clarify the role of TCF19 in influencing the malignant progression of colorectal cancer (CRC) by negatively regulating WWC1. PATIENTS AND METHODS: Relative expression levels of TCF19 and WWC1 in CRC tissues and cells were detected by quantitative Real-Time Polymerase Chain Reaction (qRT-PCR). The prognosis of CRC patients was assessed by the Kaplan-Meier method. Meanwhile, the correlation between TCF19 and pathological indexes of CRC patients was evaluated. Regulatory effects of TCF19/WWC1 on viability, colony formation ability, and migration in HT29 and HCT-8 cells were evaluated. Finally, rescue experiments were conducted to elucidate a negative feedback loop of TCF19/WWC1 in influencing the progression of CRC. RESULTS: TCF19 was significantly up-regulated in CRC, while WWC1 was down-regulated. High-level TCF19 or low-level WWC1 indicated worse survival of CRC patients. Besides, TCF19 expression level was positively correlated with the occurrence of distant metastasis in CRC. Silence of TCF19 significantly attenuated proliferative and migratory capacities of HT29 cells. However, overexpression of TCF19 yielded the opposite trends in HCT-8 cells. WWC1 expression was negatively regulated by TCF19 in CRC tissues. In addition, knockdown of WWC1 abolished the regulatory effect of TCF19 on CRC cells. CONCLUSIONS: TCF19 is closely correlated with the occurrence of distant metastasis and poor prognosis of CRC. Furthermore, it aggravates the malignant progression of CRC via negatively regulating WWC1. [ABSTRACT FROM AUTHOR]

Whether SOX2 and ACTL6A/TP63 interact with the Hippo‐YAP1 pathway in esophageal squamous cell carcinoma (ESCC) remains unclear. Here, we reveal that SOX2, ACTL6A, and TP63 are co‐amplified and upregulated in ESCC samples. Multiple SOX2 binding peaks in the locus of WWC1, a Hippo‐YAP1 regulator, and an inverse correlation between the expression of SOX2 and WWC1 are identified, suggesting direct repression of WWC1 by SOX2. Expression scores of SOX2 are higher in tumors than normal tissues and positively correlated with nuclear YAP1 staining in primary ESCC. Moreover, SOX2 gain‐of‐function significantly promotes nuclear YAP1 expression in ESCC cells while silencing of SOX2 expression inhibits YAP1 activation. SOX2 overexpression leads to a significant enhancement of cell migration and invasion as well as chemoresistance to cisplatin, whereas knockdown of SOX2 or ectopic expression of WWC1 suppresses the SOX2‐induced migration ability and invasive potential. Disruption of this SOX2‐WWC1‐YAP1 axis could be a therapeutic strategy for SOX2‐dependent tumors. [ABSTRACT FROM AUTHOR]

The WW and C2 domain containing 1 (WWC1) gene encodes a protein named WWC1 (or KIBRA), which is involved in the Hippo signaling pathway. WWC1 is often lost in triple‐negative breast cancer and has been shown to suppress tumor metastasis. In this study, 470 breast cancer patients were recruited and WWC1 expression in the tumor samples was measured with quantitative reverse transcriptase PCR. Associations of WWC1 expression with breast cancer survival were analyzed using the Cox proportional hazards regression model and Kaplan–Meier survival analysis. The relationship between WWC1 expression and methylation was evaluated in a dataset from The Cancer Genome Atlas. Using our microarray data on gene expression and the Ingenuity Pathway Analysis, we predicted the WWC1‐associated signaling pathways in breast cancer. Our results showed that low expression of WWC1 was significantly associated with advanced‐stage diseases, high‐grade tumors, and estrogen receptor‐ or progesterone receptor‐negative status. Compared to those with high expression, patients with low WWC1 had higher risk of breast cancer relapse [hazard ratio (HR) = 2.06, 95% confidence interval (CI): 1.26–3.37] and higher risk of death (HR = 2.76, 95% CI: 1.51–5.03). The association with relapse‐free survival remained significant after adjustment for disease stage, tumor grade, and hormone receptor status and was replicated in a public dataset. Analysis of high‐throughput gene expression data indicated that WWC1 was involved in the Hippo signaling pathway. Online data also suggested that DNA methylation was inversely associated with WWC1 expression. The study confirmed that low WWC1 expression was associated with aggressive breast cancer and poor survival outcomes. [ABSTRACT FROM AUTHOR]

Previous studies have indicated that glomerular podocyte injury serves a crucial role in proteinuria during the process of chronic kidney disease. The slit diaphragm of podocytes forms the final barrier to proteinuria. Dendrin, a constituent of the slit diaphragm protein complex, has been observed to relocate from the slit diaphragm to the nuclei in injured podocytes and promote podocyte apoptosis. However, the exact mechanism for nuclear relocation of dendrin remains unclear. The expression of WWC1 in podocyte injury induced by lipopolysaccharides (LPS) or adriamycin (ADR) was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blotting and the immunofluorescence assay. The role of WWC1 in podocyte apoptosis was detected by knockdown of WWC1 and flow cytometry. The mRNA and protein expression levels of apoptosis-associated genes Bcl-2-associated X (Bax) and Bcl-2 were measured by RT-qPCR and western blotting. The impact of WWC1 on dendrin nucleus relocation in vitro in podocytes was further evaluated by knockdown of WWC1. Expression of WWC1 significantly decreased in injured podocytes in vitro. The loss-of-function assay indicated that knockdown of WWC1 gene in vitro promoted podocyte apoptosis, accompanied with increased levels of the pro-apoptotic protein Bax and decreased levels of the anti-apoptotic protein Bcl-2. Furthermore, the relocation of dendrin protein was significantly promoted by knockdown of the WWC1 gene. In conclusion, the study indicated that loss of WWC1 may contribute to podocyte apoptosis by inducing nuclear relocation of dendrin protein, which provided novel insight into the molecular events in podocyte apoptosis. [ABSTRACT FROM AUTHOR]

Background: KIBRA has been suggested as a key regulator of the Hippo signaling pathway, regulating organ size, cell contact inhibition, tissue regeneration as well as tumorigenesis and cystogenesis. We recently reported that human KIBRA expression depends on a complex alternative CpG-rich promoter system. Our current study aimed at the identification of epigenetic mechanisms associated with alterations in KIBRA expression regulation. Results: We identified two separated methylation-sensitive CpG islands located to independent KIBRA promoter regions. In vitro promoter methylation analysis using human neuroblastoma (SH-SY5Y) and immortalized kidney cells (IHKE) revealed that total promoter methylation by CpG methyltransferase SssI resulted in complete abrogation of transcriptional activity (p<0.001), while partial methylation by HpaII selectively repressed KIBRA core promoter activity in kidney cells (p<0.001). Cell culture-based experiments demonstrated that 5-azacitidine may be used to restore KIBRA mRNA and protein levels, while overexpression of transcription factor SP1 also induced KIBRA upregulation (all p<0.001). Furthermore, SP1 transactivation of KIBRA transcription was largely prevented by methylation of KIBRA regulatory elements (p<0.001). Analysis of human kidney biopsies revealed that KIBRA promoter methylation was associated with human clear cell renal cell carcinoma (ccRCC; n=8 vs 16 controls, OR =1.921, [CI 95% =1.369-2.695]). The subsequent determination of KIBRA mRNA levels by real-time PCR in a larger patient sample confirmed significantly reduced KIBRA expression in ccRCC (n=32) compared to non-neoplastic human kidney tissue samples (controls, n=32, p<0.001). Conclusion: We conclude that epigenetic downregulation of tumor suppressor KIBRA may involve impaired SP1 binding to functional methylation-sensitive KIBRA promoter elements as observed in human kidney clear cell carcinoma. Our findings provide a pathophysiological basis for future studies on altered KIBRA regulation in clinical disease entities such as renal cancer. [ABSTRACT FROM AUTHOR]

The rs17070145-T variant of the WWC1 gene, coding for the KIBRA protein, has been associated with both increased episodic memory performance and lowered risk for late onset Alzheimer's disease, although the mechanism behind this protective effect has not been completely elucidated. To achieve a better understanding of the pathways modulated by rs17070145 and its associated functional variant(s), we used laser capture microdissection (LCM) and RNA-sequencing to investigate the effect of rs17070145 genotypes on whole transcriptome expression in the human hippocampus (HP) of 22 neuropathologically normal individuals, with a specific focus on the dentate gyrus (DG) and at the pyramidal cells (PC) of CA1 and CA3 sub-regions. Differential expression analysis of RNA-seq data within the HP based on the rs17070145 genotype revealed an overexpression of genes involved in the MAPK signaling pathway, potentially driven by the T/T genotype. The most important contribution comes from genes dysregulated within the DG region. Other genes significantly dysregulated, and not involved in the MAPK pathway (Adj P < 0.01 and Fold Change > |1.00|) were: RSPO4 (HP); ARC, DUSP5, DNAJB5, EGR4, PPP1R15A, WBP11P1, EGR1, GADD45B (DG); CH25H, HSPA1A, HSPA1B, TNFSF9, and NPAS4 (PC). Several evidences suggested that the MAPK signaling pathway is linked with memory and learning processes. In non-neuronal cells, the KIBRA protein is phosphorylated by ERK1/2 (involved in the MAPK signaling) in cells as well as in vitro. Several of the other dysregulated genes are involved in memory and learning processes, as well as in Alzheimer's Disease. In conclusion, our results suggest that the effect of the WWC1 rs17070145 polymorphism on memory performance and Alzheimer's disease might be due to a differential regulation of the MAPK signaling, a key pathway involved in memory and learning processes. [ABSTRACT FROM AUTHOR]

Learning and memory rely on changes in postsynaptic glutamergic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type receptor (AMPAR) number, spatial organization, and function. The Hippo pathway component WW and C2 domain-containing protein 1 (WWC1) regulates AMPAR surface expression and impacts on memory performance. However, synaptic binding partners of WWC1 and its hierarchical position in AMPAR complexes are largely unclear. Using cell-surface proteomics in hippocampal tissue of Wwc1 -deficient mice and by generating a hippocampus-specific interactome, we show that WWC1 is a major regulatory platform in AMPAR signaling networks. Under basal conditions, the Hippo pathway members WWC1 and large tumor-suppressor kinase (LATS) are associated, which might prevent WWC1 effects on synaptic proteins. Reduction of WWC1/LATS binding through a point mutation at WWC1 elevates the abundance of WWC1 in AMPAR complexes and improves hippocampal-dependent learning and memory. Thus, uncoupling of WWC1 from the Hippo pathway to AMPAR-regulatory complexes provides an innovative strategy to enhance synaptic transmission. [Display omitted] • Multilevel proteomics show WWC1 as a major postsynaptic hub for AMPA receptor complexes • WWC1/LATS dissociation enhances AMPA receptor scaffolds on the postsynaptic site • WWC1/LATS dissociation primes long-term memory in mice Stepan et al. report that the memory-enhancing effects of the Hippo pathway member WWC1 rely on its binding to LATS. Upon WWC1/LATS dissociation, WWC1 becomes an important component of postsynaptic AMPA receptor heterocomplexes and improves long-term memory in mice. [ABSTRACT FROM AUTHOR]

Inter-individual variability in memory performance has been suggested to result, in part, from genetic differences in the coding of proteins involved in long-term potentiation (LTP). The present study examined the effect of a single-nucleotide polymorphism (SNP) in the KIBRA gene (rs1707045) on episodic memory performance, using multiple measures of verbal and visual episodic memory. A total of 256 female and 130 male healthy, older adults (mean age = 60.86 years) were recruited from the Tasmanian Healthy Brain Project, undergoing both neuropsychological and genetic testing. The current study showed no significant effect of the KIBRA polymorphism on performance on the Rey Auditory Verbal Learning Task, Logical Memory test, Paired Associates Learning test or Rey Complex Figure Task. The results suggest there is little to no functional significance of KIBRA genotype on episodic memory performance, regardless of modality.

Inter-individual variability in memory performance has been suggested to result, in part, from genetic differences in the coding of proteins involved in long-term potentiation (LTP). The present study examined the effect of a single-nucleotide polymorphism (SNP) in the KIBRA gene (rs17070145) on episodic memory performance, using multiple measures of verbal and visual episodic memory. A total of 256 female and 130 male healthy, older adults (mean age = 60.86 years) were recruited from the Tasmanian Healthy Brain Project (THBP), undergoing both neuropsychological and genetic testing. The current study showed no significant effect of the KIBRA polymorphism on performance on the Rey Auditory Verbal Learning Task, Logical Memory test, Paired Associates Learning test or Rey Complex Figure Task. The results suggest there is little to no functional significance of KIBRA genotype on episodic memory performance, regardless of modality. [ABSTRACT FROM AUTHOR]

Background: Episodic memory (EM) declines with age and the rate of decline is variable across individuals. A single nucleotide polymorphism (rs17070145) in the WWC1 gene that encodes the KIBRA protein critical for long-term potentiation and memory consolidation has previously been associated with EM performance, as well as differences in hippocampal engagement during EM tasks using functional magnetic resonance imaging (fMRI). In the current study, we explore the effect of this polymorphism on EM-related activity and cognitive performance across the adult life span using fMRI. Methods: Two hundred thirty-two healthy, Caucasian subjects (18–89 years) completed a battery of cognitive tests, as well as an EM task during an fMRI scan. Results: WWC1 T carriers had significantly better delayed recall performance than CC individuals (p = .006). The relationship between increasing age and recall scores (immediate and delayed) was also significantly different between WWC1 genotype groups (p = .01). In addition to the age-related decline in hippocampal formation (HF) activation (p < .05; false discovery ratesmall volume correction -HF-region of interest), we observed an age by WWC1 genotype interaction on HF activation during encoding and retrieval. The CC group showed a significant negative association between HF activity and increasing age, while no such association was observed in the T carrier group (left HF p = .04; r-z correlation difference during encoding and retrieval; right HF p = .0008; r-z correlation difference during retrieval). Conclusions: Our results show a dynamic relationship between rs17070145 polymorphism and increasing age on neuronal activity in the hippocampal region. [Copyright &y& Elsevier]

Background: WWC1 is known to be involved in the development of cancer. Therefore, it is critical to study the molecular mechanisms and cellular roles of WWC1 in cancer therapy., Methods: In this study, we examined the effect of WWC1 on prostate cancer tumorigenesis and the role of miR-138-5p in prostate cancer. The expression levels of miR-138-5p and WWC1 in prostate cancer (Pca) tissues and cells were detected by real-time quantitative reverse transcription PCR and western blotting. Cell counting kit-8 and BrdU assays were performed to study cell proliferation and caspase-3 activity assay to detect apoptosis. Migration experiments were conducted to observe the movement ability of the cells., Results: The expression of WWC1 in Pca tissues or cell lines was increased, whereas miR-138-5p expression was decreased. MiR-138-5p targeted and partially neutralized the role of WWC1 in Pca cells. Moreover, reduced expression of WWC1 in Pca cell lines suppressed cell proliferation and migration and promoted apoptosis in vitro., Conclusions: Collectively, these findings reveal a novel mechanism by which miR-138-5p negatively regulates WWC1 in Pca., Competing Interests: Declaration of Competing Interests The authors declare that they have no competing interests., (Copyright © 2022 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.)

Background: Posttraumatic stress disorder (PTSD) results from the formation of a strong memory for the sensory-perceptual and affective representations of traumatic experiences, which is detached from the corresponding autobiographical context information. Because WWC1, the gene encoding protein KIBRA, is associated with long-term memory performance, we hypothesized that common WWC1 alleles influence the risk for a lifetime diagnosis of PTSD. Methods: Traumatic load and diagnosis of current and lifetime PTSD were assessed in two independent African samples of survivors from conflict zones who had faced severe trauma (n = 392, Rwanda, and n = 399, Northern Uganda, respectively). Array-based single nucleotide polymorphism (SNP) genotyping was performed. The influence of WWC1 tagging SNPs and traumatic load on lifetime PTSD was estimated by means of logistic regression models with correction for multiple comparisons in the Rwandan sample. Replication analysis was performed in the independent Ugandan sample. Results: An association of two neighboring SNPs in almost complete linkage disequilibrium, rs10038727 and rs4576167, with lifetime PTSD was discovered in the Rwandan sample. Although each traumatic event added to the probability of lifetime PTSD in a dose-dependent manner in both genotype groups, carriers of the minor allele of both SNPs displayed a diminished risk (p = .007, odds ratio = .29 [95% confidence interval = .15–.54]). This effect was confirmed in the independent Ugandan sample. Conclusions: This study reveals an association between two WWC1 SNPs and the likelihood of PTSD development, indicating that this memory-related gene might be involved in processes that occur in response to traumatic stress and influence the strengthening of fear memories. [Copyright &y& Elsevier]

YAP and TAZ (YAP/TAZ), two major effectors of the Hippo signaling pathway, are frequently activated in human cancers. The activity of YAP/TAZ is strictly repressed upon phosphorylation by LATS1/2 tumor suppressors. However, it is unclear how LATS1/2 are precisely regulated by upstream factors such as Hippo kinases MST1/2. Here, we show that WWC proteins (WWC1/2/3) directly interact with LATS1/2 and SAV1, and SAV1, in turn, brings in MST1/2 to phosphorylate and activate LATS1/2. Hence, WWC1/2/3 play an organizer role in a signaling module that mediates LATS1/2 activation by MST1/2. Moreover, we have defined a minimum protein interaction interface on WWC1/2/3 that is sufficient to activate LATS1/2 in a robust and specific manner. The corresponding minigene, dubbed as SuperHippo , can effectively suppress tumorigenesis in multiple tumor models. Our study has uncovered a molecular mechanism underlying LATS1/2 regulation and provides a strategy for treating diverse malignancies related to Hippo pathway dysregulation. [Display omitted] • WWC1/2/3 mediate LATS1/2 activation by MST1/2 in a SAV1-dependent manner • WWC1/2/3 organize an MST1/2-SAV1-WWC1/2/3-LATS1/2 signaling module • SuperHippo minigene mimicking WWC1/2/3 robustly and specifically activates LATS1/2 • SuperHippo effectively suppresses tumorigenesis driven by YAP/TAZ activation In this article, Qi et al. uncover a role of WWC family proteins in transducing signals from Hippo kinases to LATS1/2. Based on this mechanism, a SuperHippo minigene has been engineered to robustly and specifically activate LATS1/2, which, in turn, inhibit YAP/TAZ oncoproteins and tumorigenesis in multiple models. [ABSTRACT FROM AUTHOR]

Background/aim: WW and C2 domain-containing 1 (WWC1) protein is a suppressor of malignancies. However, there is no information on the pathological significance of WWC1 in upper urinary tract cancer (UTUC)., Patients and Methods: In this study, WWC1 immunoreactivity was investigated in 152 non-metastatic UTUC samples. The relationships between WWC1 expression and grade, pT stage, proliferative index (using an antibody to Ki-67), and the immunohistochemical expression of matrix metalloproteinase (MMP)-2 and -9 were evaluated., Results: WWC1 expression was negatively associated with tumor grade and pT stage (p<0.001). Positive expression of WWC1 was a better predictor of the UTUC recurrence and subsequent metastasis, and the multivariate analysis showed that WWC1 expression was a significant predictor of subsequent metastasis (hazard ratio=0.29, p=0.020). WWC1 expression inversely correlated with the proliferative index (odds ratio=2.59, p=0.023) and expression of MMP9 (odds ratio=2.19, p=0.040) but not with MMP2 expression, by multivariate analyses., Conclusion: WWC1 expression was negatively associated with malignant aggressiveness via the suppression of cancer cell proliferation and MMP9 expression in patients with UTUC. This suggests WWC1 to be a useful predictor and novel therapeutic target in patients with UTUC., (Copyright © 2022 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Hippo signaling acts as a tumor suppressor pathway by inhibiting the proliferation of adult stem cells and progenitor cells in various organs. Liver-specific deletion of Hippo pathway components in mice induces liver cancer development through activation of the transcriptional coactivators, YAP and TAZ, which exhibit nuclear enrichment and are activated in numerous types of cancer. The upstream-most regulators of Warts, the Drosophila ortholog of mammalian LATS1/2, are Kibra, Expanded, and Merlin. However, the roles of the corresponding mammalian orthologs, WWC1, FRMD6 and NF2, in the regulation of LATS1/2 activity and liver tumorigenesis in vivo are not fully understood. Here, we show that deletion of both Wwc1 and Nf2 in the liver accelerates intrahepatic cholangiocarcinoma (iCCA) development through activation of YAP/TAZ. Additionally, biliary epithelial cell-specific deletion of both Lats1 and Lats2 using a Sox9-Cre ERT2 system resulted in iCCA development through hyperactivation of YAP/TAZ. These findings suggest that WWC1 and NF2 cooperate to promote suppression of cholangiocarcinoma development by inhibiting the oncogenic activity of YAP/TAZ via LATS1/2.

Abstract Systematic epistasis analyses in multifactorial disorders are an important step to better characterize complex genetic risk structures. We conducted a hypothesis-free sex-stratified genome-wide screening for epistasis contributing to Alzheimer's disease (AD) susceptibility. We identified a statistical epistasis signal between the single nucleotide polymorphisms rs3733980 and rs7175766 that was associated with AD in males (genome-wide significant p Bonferroni-corrected =0.0165). This signal pointed toward the genes WW and C2 domain containing 1, aka KIBRA ; 5q34 and TLN2 (talin 2; 15q22.2). Gene-based meta-analysis in 3 independent consortium data sets confirmed the identified interaction: the most significant (p meta-Bonferroni-corrected =9.02*10−3) was for the single nucleotide polymorphism pair rs1477307 and rs4077746. In functional studies, WW and C2 domain containing 1, aka KIBRA and TLN2 coexpressed in the temporal cortex brain tissue of AD subjects (β =0.17, 95% CI 0.04 to 0.30, p =0.01); modulated Tau toxicity in Drosophila eye experiments; colocalized in brain tissue cells, N2a neuroblastoma, and HeLa cell lines; and coimmunoprecipitated both in brain tissue and HEK293 cells. Our finding points toward new AD-related pathways and provides clues toward novel medical targets for the cure of AD. [ABSTRACT FROM AUTHOR]

Triple-negative breast cancers (TNBCs) display a complex spectrum of mutations and chromosomal aberrations. Chromosome 5q (5q) loss is detected in up to 70% of TNBCs, but little is known regarding the genetic drivers associated with this event. Here, we show somatic deletion of a region syntenic with human 5q33.2-35.3 in a mouse model of TNBC. Mechanistically, we identify KIBRA as a major factor contributing to the effects of 5q loss on tumor growth and metastatic progression. Re-expression of KIBRA impairs metastasis in vivo and inhibits tumorsphere formation by TNBC cells in vitro. KIBRA functions co-operatively with the protein tyrosine phosphatase PTPN14 to trigger mechanotransduction-regulated signals that inhibit the nuclear localization of oncogenic transcriptional co-activators YAP/TAZ. Our results argue that the selective advantage produced by 5q loss involves reduced dosage of KIBRA, promoting oncogenic functioning of YAP/TAZ in TNBC., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)