Hippo通路核心蛋白在小鼠出生后不同时间点脑皮质中的表达变化

目的 探究Hippo信号通路核心蛋白在小鼠出生后不同时间点皮质中的表达变化。方法 在C57BL/6小鼠出生后（postnatal，P）3 d、6 d、9 d、3周和8周，通过测量脑重及脑横径来检测小鼠脑组织生长发育情况；通过Western Blot检测小鼠皮质中MST1、LATS1的表达；通过酪酰胺信号放大技术检测小鼠皮质中小胶质细胞在小鼠出生后五个不同时间点的数目变化以及Yes-相关蛋白（Yes-associated protein，YAP）在小胶质细胞中的定位情况。 结果 小鼠出生后早期脑重、脑横径增速显著；MST1和LATS1从P9d开始极显著降低，P3周与P8周相比无统计学意义；皮质中IBA1阳性小胶质细胞数目占比随鼠龄上升，出生后早期增速显著，伴随小胶质细胞数目增多的是YAP从核外转向核内聚集。 结论 Hippo信号通路在出生后早期的小鼠皮质中被激活，可能参与出生后脑发育时体积调控。     

Expression of Yes-associated protein in common solid tumors

The Hippo signaling pathway is a highly conserved potent regulator of cell growth, division, and apoptosis. Yes-associated protein (YAP), the nuclear effector of the Hippo pathway, is a highly conserved component of this pathway in mammalian systems. In humans, amplification of the chromosome region containing the YAP gene (11q22) has been reported in several tumor types. This study was performed to determine if YAP expression was present in 4 common types of malignant tumors that have the highest lifetime risk of causing cancer death among men and women in the United States. The YAP expression intensity and distribution were evaluated in normal tissues and compared to the most frequently occurring malignant tumors in these tissues (colonic adenocarcinoma, lung adenocarcinoma, ovarian serous cystadenocarcinoma, and ductal carcinoma of the breast). For each tissue, the nuclear and cytoplasmic YAP expression intensity was scored as negative, low, or high. We found focal expression of YAP in the progenitor and reparative cellular compartments of normal tissue. In contrast, there was strong and diffuse nuclear and cytoplasmic YAP expression in colonic adenocarcinoma, lung adenocarcinoma, and ovarian serous cystadenocarcinoma. We concluded that the potent Hippo growth regulatory pathway shows markedly different expression patterns in normal tissues of the colon, lung, and ovary compared to the 3 common malignant tumor types we examined in these tissues. Our findings suggest that activation of the Hippo signaling pathway may occur through YAP as part of cell proliferation in normal tissue homeostasis and also might be a frequently activated oncogenic pathway in 3 common malignant tumor types.     

Loss of Caenorhabditis elegans homologue of human MOB4 compromises life span,health life span and thermotolerance

Mob1/phocein family proteins are conserved from yeast to mammals. Human has four MOB genes, MOB1, 2, 3 and 4. Human MOB1 protein, which is a component of the Hippo pathway, is involved in the inhibition of yes-associated protein (YAP1) through large tumor suppressor (LATS) kinases and plays a tumor suppressive role. In contrast, MOB4 activates YAP1. Caernorhabditis elegans (C. elegans) also has four MOB genes. Moreover, C. elegans has homologues of YAP1 (Ce_YAP-1) and LATS kinases (WTS-1). Nevertheless, our previous study revealed that the Hippo pathway is not conserved in C. elegans and that heat shock activates Ce_YAP-1. We also reported that Ce_YAP-1 is involved in the regulation of life span, healthy lifespan and thermotolerance. In this study, we raised a question whether and how C. elegans homologue of MOB4 (Ce_MOB-4) is involved in the regulation of Ce_YAP-1. Ce_MOB-4 is ubiquitously expressed in adult worms. This expression pattern is similar to that of Ce_YAP-1. mob-4 loss-of-function mutants show short life span, short health life span and compromise thermotolerance. However, heat shock activates Ce_YAP-1 in mob-4 mutant. In conclusion, the role of MOB4 in the activation of YAP1 is not conserved in C. elegans.     

Synaptopodin‐2 suppresses metastasis of triple‐negative breast cancer via inhibition of YAP/TAZ activity

Triple‐negative breast cancer (TNBC) represents the most aggressive subtype of breast cancer, with a high incidence of distant metastasis; however, the underlying mechanism for this frequent recurrence remains unclear. Herein, we show that synaptopodin‐2 (SYNPO2), a putative tumour suppressor in aggressive cancer, is frequently downregulated in TNBC by methylation of the promoter of SYNPO2. Low expression levels of SYNPO2 correlated significantly with 5‐year metastatic relapse, and predicted poorer prognosis in breast cancer patients. Reintroduction of SYNPO2 inhibited the invasion and spontaneous metastasis of TNBC cells in vivo. Strikingly, downregulation of SYNPO2 is essential for the maintenance of stem cell‐like properties in TNBC cells, leading to efficient distant colonization and metastasis outgrowth. Moreover, we demonstrate that SYNPO2 inhibits the activities of YAP and TAZ by stabilizing LATS2 protein, and transduction of YAP‐S127A abrogates the repressive role of SYNPO2 in metastasis. Finally, immunohistochemical (IHC) analysis of breast cancer patient specimens indicated that the SYNPO2–LATS2–YAP axis is clinically relevant. These findings uncover a suppressive role of SYNPO2 in TNBC metastasis via inhibition of YAP/TAZ, and suggest that SYNPO2 might provide a potential prognosis marker and novel therapeutic strategy. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

LATSl-YAP信号通路对人皮肤成纤维细胞增殖及细胞外基质合成的调控

目的探讨LATSl-YAP信号通路对人皮肤成纤维细胞活力及细胞外基质合成的调控作用。方法实验分为未干预组、LATSlsiRNA干预组和YAPsiRNA干预组。构建LATSlsiRNA和YAPsiRNA,LATSlsiRNA干预组利用LATSlsiRNA转染人皮肤成纤维细胞株HS27,YAPsiRNA干预组利用YAPsiRNA转染HS27。转染后48h利用Western．blot观察LATSl、YAP和c01．1agenI的表达情况,应用MTY检测HS27细胞株的细胞活力情况。结果LATSlsiRNA转染48h后LATSl蛋白表达显著降低,YAP蛋白和collagenI蛋白表达升高,细胞活力显著增高;YAPsiRNA转染48h后LATSl蛋白表达无变化,YAP蛋白和collagenI蛋白表达降低,细胞活力显著降低。结论LATSl．YAP信号通路可调控人皮肤成纤维细胞活力和细胞外基质的合成,可能成为皮肤创伤后修复以及阻止创伤后瘢痕形成提供潜在治疗靶点。