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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]

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]

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]

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]