Análise imuno-histoquímica da Yes-Associated Protein (YAP) e sua influência sobre a proliferação celular e a apoptose em lesões odontogênicas epiteliais benignas / Immunohistochemical analysis of Yes-Associated Protein (YAP) and its influence on cell proliferation and apoptosis in benign epithelial odontogenic lesions

Introdução: Os cistos e tumores odontogênicos são lesões que apresentam comportamento biológico heterogêneo e patogênese ainda não totalmente esclarecida. A Yes-associated protein (YAP) atua como um regulador transcricional de genes envolvidos na proliferação celular e na apoptose, participando da ativação de vias associadas ao crescimento cístico e à progressão neoplásica. Objetivo: Analisar a expressão imuno-histoquímica da proteína YAP e correlacioná-la com marcadores envolvidos na proliferação celular e na apoptose em lesões odontogênicas epiteliais benignas. Metodologia: A amostra consistiu de 95 casos de lesões odontogênicas - 25 cistos dentígeros (CDs), 30 CO não sindrômicos (COs), 30 AMB convencionais (AMB-Cs) e 10 AMB unicísticos (AMB-Us) -, além de 10 espécimes de folículo dentários (FD). Foi realizada coleta dos dados clinico-demográficos dos casos, bem como análise morfológica para melhor caracterização da amostra. Os cortes histológicos foram submetidos à técnica imuno-histoquímica através da utilização dos anticorpos YAP, ciclina D1, Ki-67 e Bcl-2, e a análise da expressão destes foi realizada quali-quantitativamente, mediante metodologia adaptada. Os dados coletados seguiram para análise descritiva e estatística (p ≤ 0,05). Resultados: Houve discreta predileção por mulheres (n = 55; 57,6%) e por indivíduos na faixa etária dos 21 aos 40 anos (n = 50; 47,6%), sendo a região posterior de mandíbula mais afetada (64%). A análise da imunoexpressão de YAP revelou maiores níveis de expressão em COs, especialmente nas camadas basal e parabasal, seguido dos AMB-Us e AMB-Cs, que demonstraram moderada imunorreatividade, predominantemente nas células periféricas. Além disso, houve diferenças significativas quanto à imunoexpressão de YAP entre os grupos analisados, com existência de correlações positivas e estatisticamente significativas entre YAP e ciclina D1 em CDs e AMB-Us, e entre YAP e Ki-67 em AMB-Us (p < 0,05). Todavia, entre a imunoexpressão YAP e Bcl-2, foi verificada ausência de correlação estatisticamente significativa. Conclusões: A YAP pode exercer influência sobre a proliferação celular do epitélio de cistos e tumores odontogênicos, auxiliando, assim, na progressão das diferentes lesões odontogênicas (AU).

Background: Odontogenic cysts and tumors present heterogeneous biological behavior, and their etiopathogenesis is not fully understood yet. Yes-associated protein (YAP) acts as a transcriptional regulator of genes involved in cell proliferation and apoptosis, activating pathways associated with cystic growth and neoplastic progression. Objective: To analyze the immunohistochemical expression of YAP protein and correlate it with markers involved in cell proliferation and apoptosis in benign epithelial odontogenic lesions. Methods: The sample consisted of 95 cases of odontogenic lesions - 25 dentigerous cysts (DCs), 30 non-syndromic odontogenic keratocyst (OKCs), 30 conventional AMB (C-AMBs), and 10 unicystic AMB (UAMBs) -, in addition to 10 specimens of dental follicles (DF). Clinicodemographic data collection was carried out, as well as morphological analysis for better characterization of the sample. The histological sections were submitted to the immunohistochemical technique using YAP, cyclin D1, Ki-67, and Bcl-2 antibodies, and their immunoexpression analysis was performed qualitatively and quantitatively, through an adapted methodology. The collected data were submitted for descriptive and statistical analysis (p ≤ 0.05). Results: There was a slight predilection for women (n = 55; 57.6%) and individuals aged between 21 and 40 years (n = 50; 47.6%), with the posterior region of the mandible as the most affected site (64%). Analysis of YAP immunoexpression revealed higher expression levels in OKCs, especially in the basal and parabasal layers, followed by U-AMBs and C-AMBs, which showed moderate immunoreactivity, predominantly in peripheral cells. In addition, there were significant differences in YAP immunoexpression between the analyzed groups, with positive and statistically significant correlations between YAP and cyclin D1 in DCs and U-AMBs, and between YAP and Ki-67 in U-AMBs (p < 0.05). However, between YAP and Bcl-2 immunoexpression, there was no statistically significant correlation. Conclusions: YAP may influence on the cell proliferation of odontogenic cysts and tumors epithelium, thus helping with the progression of the different odontogenic lesions (AU) .

Activation of Yes-associated protein (YAP) improves mouse acute liver failure by alleviating ferroptosis / 细胞与分子免疫学杂志

Objective To investigate the effects of YAP on the occurrence and progression of acute liver failure by regulating the ferroptosis pathway and its underlying mechanism. Methods A total of 20 8-week-old C57BL/6 mice were randomly divided into four groups: a control group, an acute liver failure model group, a YAP agonist XMU-MP-1 treatment group and a YAP inhibitor verteporfin treatment group, five mice for each group. HE staining was used to observe the pathological changes of hepatic inflammation and necrosis. Plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were detected by liver biochemistry. Iron (Fe), malondialdehyde (MDA), glutathione (GSH) determination kits were used to measure their levels in liver tissues of each group. The changes of hepatocyte mitochondrial in each group were observed by electron microscopy. Real time PCR and Western blot analysis were used to detect the mRNA and protein expressions of YAP, glutathione peroxidase 4 (GPX4) and 5-lipoxygenase (5-LOX). Results Compared with the control group, mice in the acute liver failure model group and the YAP inhibitor verteporfin treatment group showed severe liver tissue congestion with inflammatory cell infiltration and structural damage to hepatic lobules. Liver injury was alleviated in the XMU-MP-1 treatment group. With the occurrence of liver failure, plasma ALT and AST levels significantly increased, and liver function was improved in XMU-MP-1 treatment group. Electron microscopy showed that mitochondria in hepatocytes of mice with liver failure became smaller and bilayer membrane density increased, while mitochondria changes in the XMU-MP-1 group were alleviated. In addition, the acute liver failure model group showed an increase in Fe and MDA contents, decreased protein expressions of GPX4, and enhanced expression of 5-LOX, suggesting that ferroptosis was involved in acute liver failure in C57BL/6 mice. Ferroptosis was inhibited by activation of YAP. Conclusion Activation of YAP may ameliorate liver injury by inhibiting ferroptosis.

Influência da via hippo em carcinomas de células escamosas de língua oral / Influence of the hippo pathway on oral tongue squamous cell carcinomas

O carcinoma de células escamosas de língua oral (CCELO) apresenta altas taxas de morbidade e mortalidade. Apesar dos progressos alcançados nesta área, os pesquisadores continuam em busca de biomarcadores moleculares que tenham valor preditivo no prognóstico dos pacientes e que possibilitem o desenvolvimento de novas estratégias terapêuticas. Neste contexto, várias pesquisas têm destacado o papel da via Hippo com esta finalidade. Portanto, esta pesquisa teve como objetivo avaliar se as proteínas relacionadas à Via Hippo, LATS2 e YAP1, exercem alguma influência sobre o comportamento biológico dos CCELOs. A amostra foi constituída por 26 casos de CCELO e 8 casos de mucosa oral normal como controle. Para avaliar a morfologia dos CCELOs foram utilizadas as gradações propostas pela OMS (2005) e por Almangush et al. (2014). O perfil imunoistoquímico de LATS2 e YAP1 foi avaliado por escores (0-3), com base na sua imunoexpressão em localização intracelular (núcleo e/ou citoplasma) e distribuição epitelial. Para a análise entre os parâmetros estudados foram realizados os testes estatísticos Qui-quadrado de Pearson e Exato de Fisher. A análise de sobrevida foi realizada através do método de Kaplan Meier e do teste log-rank. Para todas as avaliações foram considerados valores significativos com p<0,05. Foi observada alta expressão da LATS2 tanto em mucosa oral normal (100%) quanto na maioria dos CCELOs (73,1%), sem diferença estatística significativa (p=0,160). Foi possível evidenciar o aumento da imunoexpressão da YAP nos casos de CCELO em comparação à mucosa oral normal (p<0,001). Verificou-se ainda que a baixa expressão da LATS2 foi associada com menores taxas de sobrevida livre da doença (p=0,039). Além disso, constatou-se que a elevada expressão da YAP foi associada à classificação de alto risco do modelo BD (p=0,034), sugerindo que a imunoexpressão desta proteína pode estar associada a TEM e invasão celular em CCELO. A elevada expressão de ambas as proteínas, na maioria dos CCELOs, sugere que outras vias de sinalização, além da regulação através da LATS2, podem estar induzindo a expressão nuclear de YAP nestes tumores. Portanto, conclui-se que a via Hippo pode influenciar o comportamento biológico dos CCELOs (AU).

Oral tongue squamous cell carcinoma (OTSCC) has high morbidity and mortality rates. Despite the progress made in this area, researchers continue to search for molecular biomarkers that have predictive value in the prognosis of patients and allow the development of new therapeutic strategies. In this context, several studies have highlighted the role of the Hippo pathway for this purpose. Therefore, this research aimed to evaluate whether the proteins related to the Hippo pathway, LATS2 and YAP1, have some influence on the OTSCC biological behavior. The sample consisted of 26 OTSCC cases and 8 normal oral mucosa cases as control. For the morphological assessment of OTSCC, the gradations proposed by the WHO (2005) and by Almangush et al. (2014) were performed. The immunohistochemical profile of LATS2 and YAP1 was evaluated by scores (0-3), based on their immunoexpression in intracellular location (nucleus and/or cytoplasm) and epithelial distribution. Pearson's Chi-square and Fisher's Exact statistical tests were performed for the analysis of the studied parameters. Survival analysis was performed using the Kaplan-Meier method and the log-rank test. For all evaluations, values with p<0.05 were considered significant. High expression of LATS2 was observed both in normal oral mucosa (100%) and in most OTSCC (73,1%), with no statistically significant difference (p=0,160). It was possible to observe the increase in YAP immunoexpression in cases of OTSCC compared to the normal oral mucosa (p<0.001). It was also found that the LATS2 low expression was associated with lower rates of disease-free survival (p=0.039). Furthermore, YAP high expression was found associated with the BD model's high-risk classification (p=0.034), suggesting this protein immunoexpression may be associated with EMT and cell invasion in OTSCC. The high expression of both proteins in most OTSCC suggests that other signaling pathways, in addition to regulating through LATS2, may be inducing the nuclear YAP expression in these tumors. Therefore, it is concluded that the Hippo pathway can influence the OTSCC biological behavior (AU).

YAP regulates intestinal epithelial cell proliferation through activation of STAT3 in DSS-induced colitis and associated cancer / 中南大学学报(医学版)

OBJECTIVES@#Ulcerative colitis (UC) is a chronic, relapsing inflammation of the colon. Impaired epithelial repair is an important biological features of UC. Accelerating intestinal epithelial repair to achieve endoscopic mucosal healing has become a key goal in UC. Yes-associated protein (YAP) is a key transcriptional coactivator that regulates organ size, tissue growth and tumorigenesis. Growing studies have focused on the role of YAP in intestinal epithelial regeneration. This study explore the molecular mechanism for the role YAP in modulating colonic epithelial proliferation, repair, and the development of colitis associated cancer.@*METHODS@#We constructed the acute colitis mouse model through successive 5 days of 3% dextran sulfate sodium salt (DSS) induction. Then YAP-overexpressed mouse model was constructed by intraperitoneal injection the YAP overexpressed and negative control lentivirus into DSS mice. On the 5th day of DSS induction and the 5th day of normal drinking water after removing DSS (5+5 d), the mice were killed by spinal dislocation. The colon was taken to measure the length, and the bowel 1-2 cm near the anal canal was selected for immunohistochemical and Western blotting. We used YAP over-expressed colonic epithelial cells and small interfering signal transducer and activator of transcription 3 (STAT3) RNA to probe the regulation of YAP on STAT3, using cell counting kit-8 and scratch assays to explore the role of YAP on colonic epithelial cell proliferation. Finally, we conducted co-immunoprecipitation to test the relationship between YAP and STAT3.@*RESULTS@#After DSS treatment, the expression of YAP was dramatically diminished in crypts. Compared with the empty control mice, overexpression of YAP drastically accelerated epithelial regeneration after DSS induced colitis, presenting with more intact of structural integrity in intestinal epithelium and a reduction in the number of inflammatory cells in the mucosa. Further Western blotting, functional experiment and co-immunoprecipitation analyses showed that the expression of YAP in nucleus was significantly increased by 2 h post DSS cessation, accompanied with up-regulated total protein levels of STAT3 and phosphorylated-STAT3 (p-STAT3). Overexpression of YAP enhanced the expression of STAT3, p-STAT3, and their transcriptional targets including c-Myc and Cyclin D1. In addition, it promoted the proliferation and the "wound healing" of colonic cells. However, these effects were reversed when silencing STAT3 on YAP-overexpressed FHC cells. Moreover, protein immunoprecipitation indicated that YAP could directly interact with STAT3 in the nucleus, up-regulatvng the expressvon of STAT3. Finally, during the process of CAC, overexpression of YAP mutant caused the down-regulated expression of STAT3 and inhibited the development and progress of CAC.@*CONCLUSIONS@#YAP activates STAT3 signaling in regulation of epithelial cell proliferation and promotes mucosal regeneration after DSS induced colitis, which may serve as a potential therapeutic target in UC. However, persistent and excessive YAP activation may promote CAC development.