Yap overexpression attenuates septic cardiomyopathy by inhibiting DRP1-related mitochondrial fission and activating the ERK signaling pathway

Context: Yes-associated protein (Yap) has been linked to several cardiovascular disorders, but the role of this protein in septic cardiomyocytes is not fully understood.

Objective: The aim of our study was to explore the influence of Yap in septic cardiomyopathy in vivo and in vitro.

Materials and methods: In the current study, Yap transgenic mice and Yap adenovirus-mediated gain-of-function assays were used in an LPS-established septic cardiomyopathy model. Mitochondrial function and mitochondrial fission were determined through western blotting, immunofluorescence analysis and ELISA.

Results: Our results demonstrated that Yap expression was downregulated by LPS, whereas Yap overexpression sustained cardiac function and attenuated cardiomyocyte death. The functional exploration revealed that LPS treatment induced cardiomyocyte mitochondrial stress, as manifested by mitochondrial superoxide overproduction, cardiomyocyte ATP deprivation, and caspase-9 apoptosis activation. Furthermore, we demonstrated that LPS-mediated mitochondrial damage was controlled by mitochondrial fission. However, Yap overexpression reduced mitochondrial fission and therefore improved mitochondrial function. A molecular investigation revealed that Yap overexpression inhibited mitochondrial fission by reversing ERK activity, and the inhibition of the ERK pathway promoted DRP1 upregulation and thereby mediated mitochondrial fission activation in the presence of Yap overexpression.

Conclusions: Overall, our results suggest that the cause of septic cardiomyopathy appears to be connected with Yap downregulation. The overexpression of Yap can attenuate myocardial inflammation injury through the reduction of DRP1-related mitochondrial fission in an ERK pathway activation-dependent manner.     

Msn2p/Msn4p-activation is essential for the recovery from freezing stress in yeast

Recent data suggest that the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor subtype plays a pivotal role in the pathogenesis of effective disorders and in the action of antidepressant drugs. After chronic treatment with the antidepressants desipramine or paroxetine, we measured by immunoprecipitation and Western blotting, the changes in the interaction of AMPA receptor subunits with proteins involved in trafficking and/or stabilization of the subunits into synaptic membranes of the hippocampus. Both antidepressants increased the interaction of GluR1 subunit with stargazin and of GluR2/3 with NSF. Paroxetine increased the interaction of GluR1 with Rab4A, and desipramine markedly increased the interaction of GluR1 with SAP97. Paroxetine, but not desipramine, also increased membrane levels of CaMKII, autophosphorylated CaMKII and GluR1 phosphorylated at the CaMKII site. Interactions of GluR1 and GluR2/3 with proteins implicated in AMPA receptor trafficking and with scaffolding proteins appear to account for the enhanced membrane expression of AMPA receptors in the hippocampus after antidepressant treatment.     

YAP蛋白核过表达与卵巢癌腹膜及淋巴结转移的相关性分析

目的:探讨Yes相关蛋白(YAP)与卵巢癌腹膜及淋巴结转移的相关性。方法:选择148例原发性卵巢癌和30例正常卵巢石蜡切片标本,采用Western blot、免疫组化分析YAP蛋白在正常卵巢组织、非转移性卵巢癌组织及转移性卵巢癌组织中的表达,分析YAP蛋白在卵巢癌组织中的表达与临床病理特征的关系,并应用单因素及多因素logistics分析卵巢癌腹膜和淋巴结转移的独立危险因素。结果:YAP蛋白在正常卵巢组织、非转移性卵巢癌组织及转移性卵巢癌组织中的表达量依次增高,两两比较差异均有统计学差异(P0.05)。YAP蛋白核过表达与组织学分化、残余病灶、复发、腹膜转移以及淋巴结转移均显著相关(P0.05)。YAP蛋白核过表达是独立的影响卵巢癌腹膜(OR:5.443;95%CI:2.287-12.950;P0.001)和淋巴结转移(OR:4.477;95%CI:2.059-9.735;P0.001)的独立危险因素。结论:YAP基因核过表达与卵巢癌腹膜转移及淋巴结转移密切相关,有可能作为临床上预测卵巢癌腹膜及淋巴结转移的新的分子标记物。     

Yap1 plays a protective role in suppressing free fatty acid-induced apoptosis and promoting beta-cell survival

Mammalian pancreatic β-cells play a pivotal role in development and glucose homeostasis through the production and secretion of insulin. Functional failure or decrease in β-cell number leads to type 2 diabetes (T2D). Despite the physiological importance of β-cells, the viability of β-cells is often challenged mainly due to its poor ability to adapt to their changing microenvironment. One of the factors that negatively affect β-cell viability is high concentration of free fatty acids (FFAs) such as palmitate. In this work, we demonstrated that Yes-associated protein (Yap1) is activated when β-cells are treated with palmitate. Our loss- and gain-of-function analyses using rodent insulinoma cell lines revealed that Yap1 suppresses palmitate-induced apoptosis in β-cells without regulating their proliferation. We also found that upon palmitate treatment, re-arrangement of F-actin mediates Yap1 activation. Palmitate treatment increases expression of one of the Yap1 target genes, connective tissue growth factor (CTGF). Our gain-offunction analysis with CTGF suggests CTGF may be the downstream factor of Yap1 in the protective mechanism against FFA-induced apoptosis.