RNA-seq analysis provide new insights into mapk signaling of apolipoproteinciii-induced inflammation in porcine vascular endothelial cells

Apolipoprotein CIII (ApoCIII) has been shown to be associated with the inflammatory response, but the mechanism of its inflammatory effects remains unclear. Because vascular endothelial cells (VECs) play a key role in the development of inflammation, the present study was performed to investigate inflammatory mechanisms induced by ApoCIII in VECs. In this study, we screened differentially expressed genes (DEGs) using RNA-sequencing. The results identified 390 up-regulated genes and 257 down-regulated genes. We performed GO functional classification and KEGG pathway analysis for DEGs. Analysis of sequencing data showed that 21 genes were related to the MAPK pathway. Finally, we investigated whether ApoCIII regulates the expression of pro-inflammatory cytokines via MAPK signaling pathway. The results showed that ApoCIII increased the expression levels of IL-6, TNF-α, VCAM-1 and ICAM-1 in VECs. ApoCIII activated the phosphorylation of ERK1/2 and p38 MAPK. An inhibitor of ERK1/2 and p38 MAPK decreased the protein levels of IL-6 and TNF-α. Our findings demonstrate that ApoCIII induces pro-inflammatory cytokine production in VECs via activation of ERK1/2 and p38 MAPK phosphorylation.     

Automated oncogene detection in complex protein networks with applications to the MAPK signal transduction pathway

Activation of the extracellular signal-regulated kinases (ERK1/2; p42/p44 mitogen-activated protein kinase (MAPK)) is one of the most extensively studied signaling pathways not least because it occurs downstream of oncogenic RAS. Here, we take advantage of the wealth of experimental data available on the canonical RAS/RAF/MEK/ERK pathway of Bhalla et al. to test the utility of a newly developed nonlinear analysis algorithm designed to predict likelihood of cellular transformation. By using ERK phosphorylation as an "output signal", the method analyzes experimentally determined kinetic data and predicts putative oncogenes and tumor suppressor gene products impacting the RAS/MAPK module using a purely theoretical approach. This analysis identified several modifiers of ERK/MAPK activation described previously. In addition, several novel enzymes are identified which are not previously described to affect ERK/MAPK phosphorylation. Importantly, the nonlinear analysis enables a ranking of modifiers of MAPK activation predicting their relative importance in RAS-dependent oncogenesis. The results are compared with a linearized analysis based on sensitivity analysis about the steady state or metabolic control analysis (MCA). The results are favorable, pointing to the utility of first-order sensitivity analysis and MCA in the analysis of complex signaling networks for oncogenes.     

Signal transduction through tyrosine-phosphorylated C-terminal fragments of amyloid precursor protein via an enhanced interaction with Shc/Grb2 adaptor proteins in reactive astrocytes of Alzheimer's disease brain

The proteolytic processing of amyloid precursor protein (APP) through the formation of membrane-bound C-terminal fragments (CTFs) and of soluble beta-amyloid peptides likely influences the development of Alzheimer's disease (AD). We show that in human brain a subset of CTFs are tyrosine-phosphorylated and form stable complexes with the adaptor protein ShcA. Grb2 is also part of these complexes, which are present in higher amounts in AD than in control brains. ShcA immunoreactivity is also greatly enhanced in patients with AD and occurs at reactive astrocytes surrounding cerebral vessels and amyloid plaques. A higher amount of phospho-ERK1,2, likely as result of the ShcA activation, is present in AD brains. In vitro experiments show that the ShcA-CTFs interaction is strictly confined to glial cells when treated with thrombin, which is a well known ShcA and ERK1,2 activator and a regulator of APP cleavage. In untreated cells ShcA does not interact with either APP or CTFs, although they are normally generated. Altogether these data suggest that CTFs are implicated in cell signaling via Shc transduction machinery, likely influencing MAPK activity and glial reaction in AD patients.     

Brain Gene Expression of a Sporadic (icv-STZ Mouse) and a Familial Mouse Model (3xTg-AD Mouse) of Alzheimer’s Disease

Alzheimer’s disease (AD) can be divided into sporadic AD (SAD) and familial AD (FAD). Most AD cases are sporadic and may result from multiple etiologic factors, including environmental, genetic and metabolic factors, whereas FAD is caused by mutations of presenilins or amyloid-β (Aβ) precursor protein (APP). A commonly used mouse model for AD is 3xTg-AD mouse, which is generated by over-expression of mutated presenilin 1, APP and tau in the brain and thus represents a mouse model of FAD. A mouse model generated by intracerebroventricular (icv) administration of streptozocin (STZ), icv-STZ mouse, shows many aspects of SAD. Despite the wide use of these two models for AD research, differences in gene expression between them are not known. Here, we compared the expression of 84 AD-related genes in the hippocampus and the cerebral cortex between icv-STZ mice and 3xTg-AD mice using a custom-designed qPCR array. These genes are involved in APP processing, tau/cytoskeleton, synapse function, apoptosis and autophagy, AD-related protein kinases, glucose metabolism, insulin signaling, and mTOR pathway. We found altered expression of around 20 genes in both mouse models, which affected each of above categories. Many of these gene alterations were consistent with what was observed in AD brain previously. The expression of most of these altered genes was decreased or tended to be decreased in the hippocampus of both mouse models. Significant diversity in gene expression was found in the cerebral cortex between these two AD mouse models. More genes related to synaptic function were dysregulated in the 3xTg-AD mice, whereas more genes related to insulin signaling and glucose metabolism were down-regulated in the icv-STZ mice. The present study provides important fundamental knowledge of these two AD mouse models and will help guide future studies using these two mouse models for the development of AD drugs.     

ET-1神经分布异常与高血压鼠脑动脉神经源性调节的关系

目的探讨ET-1（Endothelin-1,ET-1）能神经纤维分布与高血压鼠脑血管的神经源性调节的关系,探讨ET-1神经是否参与高血压时期脑血流的调节。方法应用免疫组织化学技术观察自发性高血压鼠和Wistar正常血压鼠脑底动脉（包括大脑前动脉、大脑中动脉、大脑后动脉和基底动脉）ET-1能神经纤维的分布密度和走行方式。结果自发性高血压鼠和Wistar正常血压鼠脑底动脉均可见棕褐色的ET-1能免疫反应阳性纤维,似细线状,攀附于血管壁上,自发性高血压鼠脑底动脉各主要分支ET-1能免疫反应阳性纤维密度较Wistar正常血压鼠明显增加,纤维走行大多呈网状。结论实验结果提示自发性高血压鼠脑底动脉增加的ET-1能免疫反应阳性纤维可能与脑血管的神经源性调节有关;高密度的ET-1能神经纤维可能涉及高血压时期脑血流的调节。     

The protein kinase ERK3 is encoded by a single functional gene: genomic analysis of the ERK3 gene family

Extracellular signal-regulated kinase 3 (ERK3) is a distantly related member of the mitogen-activated protein (MAP) kinase family of serine/threonine kinases. Here, we report the characterization of the genomic loci encoding ERK3 in mice and humans. The mouse ERK3 gene (Mapk6) spans more than 20 kb and is split into six exons. Its structure is similar to that of the human MAPK6 gene, which extends over 40 kb. We also identified and characterized a mouse Mapk6 processed pseudogene. In humans, database analysis has revealed the presence of six MAPK6 processed pseudogenes localized on four different chromosomes. We further show that the structure of MAPK6 is closely related to that of the gene encoding the homologous protein kinase p63(MAPK) (MAPK4), suggesting that the two genes arose by duplication. Our analysis demonstrates that the ERK3 subfamily of MAP kinase genes is composed of two functional genes, MAPK6 and MAPK4, and several pseudogenes.     

miR-124与MAPK/ERK通路对调节脑梗死大鼠神经细胞凋亡的影响

摘要 目的：研究miR-124和MAPK/ERK途径对脑梗死大鼠神经细胞凋亡的影响及其可能的机制。方法：本研究将SD大鼠随机分为假手术组（Sham组）、模型组（CI组）、miR-124组（miR组）、脑梗死+miR-124组（CI+miR组）和脑梗死+MEK/ERK阻滞剂组（CI+U0126组）,采用mNSS评分法评估大鼠神经功能损伤程度,采用TTC染色检测脑梗死体积,采用尼式染色检查脑组织的病理情况,采用TUNEL染色法检测大鼠脑神经细胞凋亡,TRIzol法提取总RNA,RT-PCR检测miR-124、ERK1和ERK2基因表达,蛋白质免疫印迹法检测Caspase-3、Bax、Bcl-2、MEK2和ERK1蛋白表达水平。结果：与Sham组和miR组相比,CI组、CI+miR组和CI+U0126组大鼠的脑梗死体积、mNSS评分和脑含水量均显著增加（P<0.01）。Sham组、miR组、CI+miR组和CI+U0126组大鼠的脑组织中尼式体的数量显著高于CI组,模型组大鼠的脑神经元结构被破坏且出现核移位和细胞坏死等病理变化;与Sham组和miR组相比,CI组大鼠中miR-124的表达水平显著降低（P<0.01）,CI+miR组和CI+U0126组大鼠中miR-124的表达水平显著上调（P<0.01）。TUNEL染色结果显示,与模型组相比,CI+miR组和CI+U0126组大鼠中凋亡数量显著减少（P<0.01）,ERK1和ERK2的mRNA相对表达水平均显著下调（P<0.01）。与模型组相比,CI+miR组和CI+U0126组大鼠脑组织中Caspase-3和Bax蛋白表达水平显著下调,Bcl-2蛋白的表达水平显著上调（P<0.01）。与模型组相比,CI+miR组和CI+U0126组大鼠脑组织中磷酸化的p-MEK-2和p-ERK1/2蛋白表达水平均显著下调（P<0.01）。结论：miR-124可能通过抑制MAPK/ERK信号通路的激活,减少脑梗死大鼠的神经细胞的凋亡,最终发挥保护作用。     

Regional and Temporal Changes in Proteomic Profile after Middle Cerebral Artery Occlusion with or without Reperfusion in Rats

Although DNA microarray studies showed up-regulation of various genes, failures of translation of many genes are expected to occur under ischemic conditions even in the penumbra with mild reduction in cerebral blood flow. We applied surface enhanced laser desorption/ionization-time of flight mass spectrometry (SELDI-TOF-MS) technology to study proteomic profile at 6, 12, and 24 h after photothrombotic middle cerebral artery (MCA) occlusion with or without YAG laser-induced reperfusion in adult male spontaneously hypertensive rats. Of the 43 protein peaks that differed from the sham-operation group with a criterion (no overlap of peak intensities between the two groups), 36 peaks (84%) were down-regulated, and seven were up-regulated. All increased peaks showed greater than twofold increases (up to 8.1 fold) compared with those in the sham-operation group. Effects of reperfusion were observed mainly at 24 h after 1 h of MCA occlusion only in the penumbra, where 23 of 32 peaks returned toward the control values, whereas none of 33 peaks showed such attenuation in the ischemic core. Major ischemia-induced changes in protein peaks detected with SELDI-TOF-MS were down-regulations. The present study showed that dynamic changes of protein profile were associated with progression and recovery of the ischemic core and penumbra.     

The hepatitis E virus ORF3 protein regulates the expression of liver-specific genes by modulating localization of hepatocyte nuclear factor 4

The hepatitis E virus (HEV) is a small RNA virus and the cause of acute viral hepatitis E. The open reading frame 3 protein (pORF3) of HEV appears to be a pleiotropic regulatory protein that helps in the establishment, propagation and progression of viral infection. However, the global cellular effects of this protein remain to be explored. In the absence of traditional in vitro viral infection systems or efficient replicon systems, we made an adenovirus based ORF3 protein expression system to study its effects on host cell gene expression. We infected Huh7 hepatoma cells with recombinant adenoviruses expressing pORF3 and performed microarray-based gene expression analyses. Several genes down regulated in pORF3-expressing cells were found to be under regulation of the liver-enriched hepatocyte nuclear factor 4 (HNF4), which regulates hepatocyte-specific gene expression. While HNF4 localizes to the nucleus, its phosphorylation results in impaired nuclear localization of HNF4. Here we report that pORF3 increases HNF4 phosphorylation through the ERK and Akt kinases, which results in impaired nuclear translocation of HNF4 and subsequently the down modulation of HNF4-responsive genes in pORF3-expressing cells. We propose that modulation of several hepatocyte specific genes by pORF3 will create an environment favorable for viral replication and pathogenesis.     

miR-380调控羊驼黑色素细胞MAPK/ERK信号通路

miR-380是不同羊驼毛色中差异表达的基因之一,但是否与黑色素生成有关未见报道。为了丰富调控黑色素生成的机制,挖掘黑色素生成路径中所涉及到的更多新的基因并揭示miR 380在黑色素细胞中的功能,本实验通过生物信息学方法预测出MAPK信号通路的成员MAP3K6是miR-380的靶基因之一。在293T细胞中共转染miR-380和MAP3K6后,与对照组相比双荧光报告酶活性下降（28.92 ± 25.63）%(P<0.01) ,下降趋势明显,说明MAP3K6可能是miR-380的靶基因之一;在羊驼黑色素细胞中转染miR-380后,MAP3K6、MEK1、ERK1/2、CREB和MITF在转录水平的表达量与NC组相比具有显著下降趋势,其中CREB下降趋势尤为显著（64.20 ± 54.30）%（P<0.01）,Western印迹检测MAP3K6、p-MEK1、p-ERK1/2、CREB和MITF在蛋白质水平的表达与NC组相比下降趋势明显且p-MEK1和CREB基因下降极为显著,分别为（29.09 ± 10.68）%（P<0.001）和（47.12 ± 6.70）%（P<0.001）,抑制组则反之。通过 Masson-Fontana黑色素颗粒染色法检测miR-380抑制黑色素细胞产生黑色素颗粒,用紫外分光度法检测真黑素（eumelanin,EM）和褐黑素（pheomelanin,PM）,含量结果提示EM与PM含量分别下降为（38.63 ± 2.00）%（P<0.01）,（54.10 ± 5.73）%（P<0.001）且PM含量下降极为显著。综上所述miR-380通过靶向抑制MAP3K6等基因的表达,从而对MAPK/ERK信号通路起调控作用,最终影响黑色素生成生物学功能,此研究对哺乳动物毛色形成机制和防止皮肤受紫外辐射有重要意义。     

LOC100996425 acts as a promoter in prostate cancer by mediating hepatocyte nuclear factor 4A and the AMPK/mTOR pathway

The involvement of long non-coding RNAs (lncRNAs), differentially expressed genes and signals in prostate cancer (PCa) continues to be a subject of investigation. This study determined effects of LOC100996425 on human PCa by targeting hepatocyte nuclear factor 4A (HNF4A) via the AMPK/mTOR pathway. PCa and adjacent normal tissues were obtained to characterize expression pattern of LOC100996425, HNF4A and the AMPK/mTOR pathway-related genes. Then, the target gene of LOC100996425 was determined with lncRNA target prediction website and further verification was obtained through luciferase assay and ribonucleoprotein immunoprecipitation. After that, PCa cells were introduced with LOC100996425, HNF4A, siLOC100996425 or siHNF4A to explore the specific significance of LOC100996425 and HNF4A in PCa. The mechanism associated with AMPK/mTOR pathway was investigated using AMPK inhibitor or activator. LOC100996425 was up-regulated, while HNF4A was down-regulated in the PCa tissues. HNF4A was a target gene of LOC100996425. PCa cells transfected with either siLOC100996425 or HNF4A displayed reduced rates of PCa cell proliferation and migration while elevating cell apoptosis. HNF4A overexpression reversed the promotive effect of LOC100996425 overexpression on PCa. The activation of AMPK pathway involved in the cancer progression mediated by LOC100996425. Down-regulation of LOC100996425 retards progression of PCa through HNF4A-mediated AMPK/mTOR pathway.     

Calcium-induced matrix metalloproteinase 9 gene expression is differentially regulated by ERK1/2 and p38 MAPK in oral keratinocytes and oral squamous cell carcinoma

Matrix metalloproteinases (MMPs) play an important role in the invasive behavior of a number of cancers including oral squamous cell cancer (OSCC), and increased expression of MMP-9 is correlated with invasive and metastatic OSCC. Because calcium is an important regulator of keratinocyte function, the effect of modulating extracellular calcium on MMP-9 expression in OSCC cell lines was evaluated. Increasing extracellular calcium induced a dose-dependent increase in MMP-9 expression in immortalized normal and premalignant oral keratinocytes, but not in two highly invasive OSCC cell lines. Differential activation of MAPK signaling was also induced by calcium. p38 MAPK activity was down-regulated, whereas ERK1/2 activity was enhanced. Pharmacologic inhibition of p38 MAPK activity or expression of a catalytically inactive mutant of the upstream kinase MAPK kinase 3 (MKK3) increased the calcium induced MMP-9 gene expression, demonstrating that p38 MAPK activity negatively regulated this process. Interestingly blocking p38 MAPK activity enhanced ERK1/2 phosphorylation, suggesting reciprocal regulation between the ERK1/2 and p38 MAPK pathways. Together these data support a model wherein calcium-induced MMP-9 expression is differentially regulated by the ERK1/2 and p38 MAPK pathways in oral keratinocytes, and the data suggest that a loss of this regulatory mechanism accompanies malignant transformation of the oral epithelium.     

Human apoB overexpression and a high-cholesterol diet differently modify the brain APP metabolism in the transgenic mouse model of atherosclerosis

Epidemiological and biochemical data suggest a link between the cholesterol metabolism, the amyloid precursor protein (APP) processing and the increased cerebral beta-amyloid (Abeta) deposition in Alzheimer's disease (AD). The individual and combined effects of a high-cholesterol (HC) diet and the overexpression of the human apoB-100 gene were therefore examined on the cerebral expression and processing of APP in homozygous apoB-100 transgenic mice [Tg (apoB(+/+))], a validated model of atherosclerosis. When fed with 2% cholesterol for 17 weeks, only the wild-type mice exhibited significantly increased APP695 (123%) and APP770 (138%) mRNA levels in the cortex. The HC diet-induced hypercholesterolemia significantly increased the APP isoform levels in the membrane-bound fraction, not only in the wild-type animals (114%), but also in the Tg apoB(+/+) group (171%). The overexpression of human apoB-100 gene by the liver alone reduced the brain APP isoform levels in the membrane-bound fraction (78%), whereas the levels were increased by the combined effect of HC and the overexpression of the human apoB-100 gene (134%). The protein kinase C and beta-secretase protein levels were not altered by the individual or combined effects of these two factors. Our data indicate that the two atherogenic factors, the HC diet and the overexpression of the human apoB-100 gene by the liver, could exert different effects on the processing and expression of APP in the mice brain.     

Ubiquitin-conjugating enzymes UBC4 and UBC5 mediate selective degradation of short-lived and abnormal proteins.

Ubiquitin-conjugating enzymes catalyse the covalent attachment of ubiquitin to target proteins. Members of this enzyme family are involved in strikingly diverse cellular functions: UBC2 (RAD6) is central to DNA repair, UBC3 (CDC34) is involved in cell cycle control. We have cloned the genes for two novel ubiquitin-conjugating enzymes, UBC4 and UBC5, from the yeast Saccharomyces cerevisiae. These enzymes mediate selective degradation of short-lived and abnormal proteins. UBC4 and UBC5 are closely related in sequence and complementing in function. Expression of UBC4 and UBC5 genes is heat inducible. UBC4 and UBC5 enzymes generate high mol. wt ubiquitin-protein conjugates in vivo consistent with previous studies which suggested that attachment of multiple ubiquitin molecules to proteolytic substrates is required for their selective degradation. UBC4 and UBC5 enzymes comprise a major part of total ubiquitin-conjugation activity in stressed cells. Turnover of short-lived proteins and canavanyl-peptides but not of long-lived proteins is markedly reduced in ubc4ubc5 mutants. Loss of UBC4 and UBC5 activity impairs cell growth, leads to inviability at elevated temperatures or in the presence of an amino acid analog, and induces the stress response.     

Signaling pathways for TNF production induced by human aminoacyl-tRNA synthetase-associating factor,p43

The p43 protein is associated with human macromolecular aminoacyl tRNA synthetase complex and secreted to up-regulate diverse proinflammatory genes including TNF. Here we focused on the p43-induced TNF production and determined its responsible signal pathway. The p43-induced TNF production was mediated by the activation of MAPK family members, ERK and p38 MAPK, and by IkappaB degradation leading to the activation of NFkappaB. We also studied the upstream molecules for ERK and p38 MAPK by using a variety of inhibitors. The inhibitors for protein kinase C (PKC) and phospholipase C (PLC) prevented the p43-induced TNF production. Interestingly, all of the effective drugs inhibited the ERK activity, while the drugs had no effects on p38 MAPK activity and IkappaB degradation. Together, the p43-induced TNF production was controlled by NFkB, p38 MAPK, and ERK that is dependent on the activities of PLC and PKC.