Nedd9 protein, a Cas-L homologue, is upregulated after transient global ischemia in rats: possible involvement of Nedd9 in the differentiation of neurons after ischemia

Abdominal surgery under ketamine anesthesia during second trimester impairs hippocampal learning and memory of offspring by regulating dendrite spine remodeling in rats

Recent evidence showed that general anesthesia produces long-term neurotoxicity and cognitive dysfunction. However, it remains unclear whether maternal non-obstetric surgery under ketamine anesthesia during second trimester causes cognitive impairment in offspring. The present study assigned pregnant rats into three groups: 1) normal control group receiving no anesthesia and no surgery, 2) ketamine group receiving ketamine anesthesia for 2 h on the 14th day of gestation but no surgery, and 3) surgery group receiving abdominal surgery under ketamine anesthesia on the 14th day of gestation. On postnatal day 1, the offspring rats in Ketamine group and surgery group were assigned to receive intra-peritoneal injection of Senegenin (15 mg/kg), once per day for consecutive 14 days. The offspring's spatial perception, anxiety-like behavior, and learning and memory were evaluated. Then the offspring's hippocampal tissues were collected. The offspring of the surgery group were impaired in the spatial perception in the cliff avoidance test and the spatial learning and memory in the Morris water maze test. Accordingly, the activity of histone deacetylases increased, the protein levels of NEDD9, BDNF, p-TrkB, Syn and PSD-95 decreased, and the density of dendritic spines reduced in the hippocampus of the offspring of the surgery group, and such effects were not seen in the offspring of the ketamine group, neither in the offspring of control group. Senegenin alleviated the learning and memory impairment, and increased the protein levels of NEDD9, BDNF, p-TrkB, Syn and PSD-95 and the density of dendritic spines in the offspring of the surgery group. ketamine anesthesia plus surgery during second trimester impairs hippocampus-dependent learning and memory, and the deficits could be rescued by treatment with Senegenin.

Discrete hippocampal projections are differentially regulated by parvalbumin and somatostatin interneurons

People with schizophrenia show hyperactivity in the ventral hippocampus (vHipp) and we have previously demonstrated distinct behavioral roles for vHipp cell populations. Here, we test the hypothesis that parvalbumin (PV) and somatostatin (SST) interneurons differentially innervate and regulate hippocampal pyramidal neurons based on their projection target. First, we use eGRASP to show that PV-positive interneurons form a similar number of synaptic connections with pyramidal cells regardless of their projection target while SST-positive interneurons preferentially target nucleus accumbens (NAc) projections. To determine if these anatomical differences result in functional changes, we used in vivo opto-electrophysiology to show that SST cells also preferentially regulate the activity of NAc-projecting cells. These results suggest vHipp interneurons differentially regulate that vHipp neurons that project to the medial prefrontal cortex (mPFC) and NAc. Characterization of these cell populations may provide potential molecular targets for the treatment schizophrenia and other psychiatric disorders associated with vHipp dysfunction.

Comprehensive Analysis of Potential miRNA-Target mRNA-Immunocyte Subtype Network in Cerebral Infarction

INTRODUCTION

Cerebral infarction (CI) is one of the leading causes of serious long-term disability and mortality.

OBJECTIVE

We aimed to identify potential miRNAs and target mRNAs and assess the involvement of immunocyte infiltration in the process of CI.

METHODS

First, miRNA and mRNA data were downloaded from the Gene Expression Omnibus database, followed by differential expression analysis. Second, correlation analysis between differentially expressed mRNAs and differential immunocyte subtypes was performed through the CIBERSORT algorithm. Third, the regulatory network between miRNAs and immunocyte subtype-related mRNAs was constructed followed by the functional analysis of these target mRNAs. Fourth, correlation validation between differentially expressed mRNAs and differential immunocyte subtypes was performed in the GSE37587 dataset. Finally, the diagnostic ability of immunocyte subtype-related mRNAs was tested.

RESULTS

Up to 17 differentially expressed miRNAs and 3,267 differentially expressed mRNAs were identified, among which 310 differentially expressed mRNAs were significantly associated with immunocyte subtypes. Several miRNA-target mRNA-immunocyte subtype networks including hsa-miR-671-3p-ZC3HC1-neutrophils, hsa-miR-625-CD5-monocytes, hsa-miR-122-ACOX1/DUSP1/NEDD9-neutrophils, hsa-miR-455-5p-SLC24A4-monocytes, and hsa-miR-455-5p-SORL1-neutrophils were identified. LAT, ACOX1, DUSP1, NEDD9, ZC3HC1, BIN1, AKT1, DNMT1, SLC24A4, and SORL1 had a potential diagnostic value for CI.

CONCLUSIONS

The network including miRNA, target mRNA, and immunocyte subtype may be novel regulators and diagnostic and therapeutic targets in CI.

NEDD9 Facilitates Hypoxia-Induced Gastric Cancer Cell Migration via MICAL1 Related Rac1 Activation

Aims and Hypothesis: NEDD9 is highly expressed in gastric cancer and has a significant involvement in its pathogenesis. However, the mechanism behind hypoxia-promoted cancer cell migration and its regulation because of NEDD9 is still unknown. The aim of this study is to investigate the involvement of NEDD9 in gastric cancer cell migration under hypoxia and explore the underlying potential molecular mechanisms.

Glucocorticoids, genes and brain function

The identification of key genes in transcriptomic data constitutes a huge challenge. Our review of microarray reports revealed 88 genes whose transcription is consistently regulated by glucocorticoids (GCs), such as cortisol, corticosterone and dexamethasone, in the brain. Replicable transcriptomic data were combined with biochemical and physiological data to create an integrated view of the effects induced by GCs. The most frequently reported genes were Errfi1 and Ddit4. Their up-regulation was associated with the altered transcription of genes regulating growth factor and mTORC1 signaling (Gab1, Tsc22d3, Dusp1, Ndrg2, Ppp5c and Sesn1) and progression of the cell cycle (Ccnd1, Cdkn1a and Cables1). The GC-induced reprogramming of cell function involves changes in the mRNA level of genes responsible for the regulation of transcription (Klf9, Bcl6, Klf15, Tle3, Cxxc5, Litaf, Tle4, Jun, Sox4, Sox2, Sox9, Irf1, Sall2, Nfkbia and Id1) and the selective degradation of mRNA (Tob2). Other genes are involved in the regulation of metabolism (Gpd1, Aldoc and Pdk4), actin cytoskeleton (Myh2, Nedd9, Mical2, Rhou, Arl4d, Osbpl3, Arhgef3, Sdc4, Rdx, Wipf3, Chst1 and Hepacam), autophagy (Eva1a and Plekhf1), vesicular transport (Rhob, Ehd3, Vps37b and Scamp2), gap junctions (Gjb6), immune response (Tiparp, Mertk, Lyve1 and Il6r), signaling mediated by thyroid hormones (Thra and Sult1a1), calcium (Calm2), adrenaline/noradrenaline (Adcy9 and Adra1d), neuropeptide Y (Npy1r) and histamine (Hdc). GCs also affected genes involved in the synthesis of polyamines (Azin1) and taurine (Cdo1). The actions of GCs are restrained by feedback mechanisms depending on the transcription of Sgk1, Fkbp5 and Nr3c1. A side effect induced by GCs is increased production of reactive oxygen species. Available data show that the brain's response to GCs is part of an emergency mode characterized by inactivation of non-core activities, restrained inflammation, restriction of investments (growth), improved efficiency of energy production and the removal of unnecessary or malfunctioning cellular components to conserve energy and maintain nutrient supply during the stress response.

Microarray analysis of an synthetic α-synuclein induced cellular model reveals the expression profile of long non-coding RNA in Parkinson's disease

Long non-coding RNAs (lncRNAs) are a new research focus that are reported to influence the pathogenetic process of neurodegenerative disorders. To uncover new disease-associated genes and their relevant mechanisms, we carried out a gene microarray analysis based on a Parkinson's disease (PD) in vitro model induced by α-synuclein oligomers. This cellular model induced by 25 μmol/L α-synuclein oligomers has been confirmed to show the stable, transmissible neurotoxicity of α-synuclein, a typical PD pathological marker. And several differentially expressed lncRNAs and mRNAs were identified in this model, such as G046036, G030771, AC009365.4, RPS14P3, CTB-11I22.1, and G007549. Subsequent ceRNA analysis determined the potential relationships between these lncRNAs and their associated mRNAs and microRNAs. The results of the present study widen our horizon of PD susceptibility genes and provide new pathways towards efficient diagnostic biomarkers and therapeutic targets for PD.

Actin polymerization-dependent activation of Cas-L promotes immunological synapse stability

The immunological synapse formed between a T-cell and an antigen-presenting cell is important for cell-cell communication during T-cell-mediated immune responses. Immunological synapse formation begins with stimulation of the T-cell receptor (TCR). TCR microclusters are assembled and transported to the center of the immunological synapse in an actin polymerization-dependent process. However, the physical link between TCR and actin remains elusive. Here we show that lymphocyte-specific Crk-associated substrate (Cas-L), a member of a force sensing protein family, is required for transport of TCR microclusters and for establishing synapse stability. We found that Cas-L is phosphorylated at TCR microclusters in an actin polymerization-dependent fashion. Furthermore, Cas-L participates in a positive feedback loop leading to amplification of Ca2+ signaling, inside-out integrin activation, and actomyosin contraction. We propose a new role for Cas-L in T-cell activation as a mechanical transducer linking TCR microclusters to the underlying actin network and coordinating multiple actin-dependent structures in the immunological synapse. Our studies highlight the importance of mechanotransduction processes in T-cell-mediated immune responses.

High expression of HEF1 predicts a poorer prognosis of hepatocellular carcinoma: A retrospective study

Human enhancer of filamentation 1 (HEF1), a scaffold protein, is highly expressed in a variety of cancer types and is involved cancer cell growth, migration and invasion. The prognostic value of HEF1 in hepatocellular carcinoma (HCC) remains to be elucidated. The aim of the present study was to assess the association between the expression of HEF1, the clinical/pathological parameters and survival in HCC. In the present study, immunohistochemistry was performed to investigate the protein expression of HEF1 in 123 hepatocellular carcinoma tissues and their adjacent normal liver tissues. Spearman's rank correlation, Kaplan-Meier plots and Cox regression model were used to analyze the data. Overexpression of HEF1 protein was observed in HCC tissue when compared with their adjacent non-malignant liver tissue. High expression of HEF1 correlated with higher advanced tumor, node, metastasis (TNM) stage and vascular invasion (P<0.05). In univariate and multivariate analysis, the expression of HEF1 was identified as an independent prognostic factor in the 123 patients with HCC. In subgroup analysis, high expression of HEF1 correlated with a poorer prognosis in advanced (TNM III+IV) stages (P<0.05). These findings demonstrated the potential value of detecting the expression of HEF1 by immunohistochemistry as a prognostic biomarker and therapeutic target for patients with HCC.

Mice null for NEDD9 (HEF1α) display extensive hippocampal dendritic spine loss and cognitive impairment

NEDD9 (neural precursor cell expressed, developmentally down-regulated 9) is a member of the CAS (Crk-associated substrate) family of scaffolding proteins that regulate cell adhesion and migration. A Nedd9 knock-out/lacZ knock-in mouse (Nedd9(-/)(-)) was developed in order to study Nedd9 expression and function in the nervous system. Herein we show that NEDD9 is expressed in the adult brain and is prominently expressed in the hippocampus. Behavioral testing uncovered functional deficits in Nedd9(-)(/)(-) mice. In the Morris water maze test, Nedd9(-)(/)(-) mice showed deficits in both the ability to learn the task as well as in their ability to recall the platform location. There was no change in the gross morphology of the hippocampus, and stereological analysis of BrdU-labeled newly formed hippocampal cells suggested that this defect is not secondary to altered neurogenesis. However, analysis of the hippocampus revealed extensive loss of dendritic spine density in both the dentate gyrus (DG) and CA1 regions. Spine loss occurred equally across all branch orders and regions of the dendrite. Analysis of spine density in Nedd9(-)(/)(-) mice at 1.5, 6 and 10 months revealed an age-dependent spine loss. This work shows that NEDD9 is required for the maintenance of dendritic spines in the hippocampus, and suggests it could play a role in learning and memory.

Preclinical and clinical studies of the NEDD9 scaffold protein in cancer and other diseases

Cancer progression requires a significant reprogramming of cellular signaling to support the essential tumor-specific processes that include hyperproliferation, invasion (for solid tumors) and survival of metastatic colonies. NEDD9 (also known as CasL and HEF1) encodes a multi-domain scaffolding protein that assembles signaling complexes regulating multiple cellular processes relevant to cancer. These include responsiveness to signals emanating from the T and B cell receptors, integrins, chemokine receptors, and receptor tyrosine kinases, as well as cytoplasmic oncogenes such as BCR-ABL and FAK- and SRC-family kinases. Downstream, NEDD9 regulation of partners including CRKL, WAVE, PI3K/AKT, ERK, E-cadherin, Aurora-A (AURKA), HDAC6, and others allow NEDD9 to influence functions as pleiotropic as migration, invasion, survival, ciliary resorption, and mitosis. In this review, we summarize a growing body of preclinical and clinical data that indicate that while NEDD9 is itself non-oncogenic, changes in expression of NEDD9 (most commonly elevation of expression) are common features of tumors, and directly impact tumor aggressiveness, metastasis, and response to at least some targeted agents inhibiting NEDD9-interacting proteins. These data strongly support the relevance of further development of NEDD9 as a biomarker for therapeutic resistance. Finally, we briefly discuss emerging evidence supporting involvement of NEDD9 in additional pathological conditions, including stroke and polycystic kidney disease.

Elevated expression of NEDD9 is associated with metastatic activity in gastric cancer

Objective

To investigate the protein and mRNA expression of NEDD9 in gastric cancer (GC) tissues, adjacent atypical hyperplasia tissues, and normal gastric mucosa tissues, and analyze its relationship with the pathological features and prognosis of GC.

Methods

Forty cases of GC tissues, 20 cases of adjacent atypical hyperplasia tissues, and 40 cases of normal gastric mucous tissues were collected. Immunohistochemistry and Western blot were used to examine the expression of NEDD9 protein in various tissues. Situ hybridization and reverse transcription polymerase chain reaction were applied to detect the expression of NEDD9 mRNA in various tissues. The correlation of NEDD9 expression with invasion and metastasis of GC was analyzed.

Results

The protein expression level of NEDD9 was significantly higher in GC tissues than in adjacent atypical hyperplasia tissues and normal gastric mucous tissues (P<0.05). The protein expression level of NEDD9 was positively related to the invasion depth of carcinoma and tumor lymph node metastasis (P<0.05), but unrelated to age, sex, tumor size, and clinical classification of cancer (P<0.05). The mRNA expression level of NEDD9 was also significantly higher in GC tissues than in adjacent atypical hyperplasia tissues and normal gastric mucous tissues (P<0.05), and positively related with the tumor lymph node metastasis and invasion depth of carcinoma (P<0.05).

Conclusion

NEDD9 is involved in the occurrence and development of GC, and it may be an important biological marker of GC metastasis and infiltration.

A complex RARE is required for the majority of Nedd9 embryonic expression

Neural precursor cell expressed, developmentally down-regulated 9 (Nedd9, Casl, Hef1, p105cas, Ef1) is a scaffolding protein that assembles complexes involved in regulating cell adhesion, migration, division, and survival. Nedd9 is found very early in the developing embryonic nervous system. A highly conserved complex retinoic acid response element (RARE) is located 485 base pairs (bp) upstream of exon 2B in the promoter of the Nedd9 gene. Mice transgenic for a 5.2 kilobase (kb) region of the 2B Nedd9 promoter containing the RARE upstream of a lacZ reporter gene [Nedd9(RARE)-lacZ] show a large subset of the normal endogenous Nedd9 expression including that in the caudal hindbrain neuroepithelium, spinal cord, dorsal root ganglia (drg) and migrating neural crest (ncc). However, the transgenic mice do not recapitulate the native Nedd9 expression pattern in presumptive rhombomeres (pr) 3 and 5 of the early hindbrain, the base of the neuroepithelium in the midbrain, nor the forebrain telencephalon. Thus, the 5.2 kb region containing the intact RARE drives a large subset of Nedd9 expression, with additional sequences outside of this region needed to define the full complement of expression. When the 5.2 kb construct is modified (eight point mutations) to eliminate responsiveness of the RARE to all-trans retinoic acid (atRA) [Nedd9(mutRARE)-lacZ], virtually all β-galactosidase (β-gal, lacZ) expression is lost. Exposure of Nedd9(RARE)-lacZ transgenic embryos to excess atRA at embryonic day 8.0 (E8.0) leads to rostral ectopic transgene expression within 6 h whereas the Nedd9(mutRARE)-lacZ mutant does not show this effect. Thus the RARE upstream of the Nedd9 2B promoter is necessary for much of the endogenous gene expression during early development as well as ectopic expression in response to atRA.

Adaptors for disorders of the brain? The cancer signaling proteins NEDD9, CASS4, and PTK2B in Alzheimer's disease

No treatment strategies effectively limit the progression of Alzheimer's disease (AD), a common and debilitating neurodegenerative disorder. The absence of viable treatment options reflects the fact that the pathophysiology and genotypic causes of the disease are not well understood. The advent of genome-wide association studies (GWAS) has made it possible to broadly investigate genotypic alterations driving phenotypic occurrences. Recent studies have associated single nucleotide polymorphisms (SNPs) in two paralogous scaffolding proteins, NEDD9 and CASS4, and the kinase PTK2B, with susceptibility to late-onset AD (LOAD). Intriguingly, NEDD9, CASS4, and PTK2B have been much studied as interacting partners regulating oncogenesis and metastasis, and all three are known to be active in the brain during development and in cancer. However, to date, the majority of studies of these proteins have emphasized their roles in the directly cancer relevant processes of migration and survival signaling. We here discuss evidence for roles of NEDD9, CASS4 and PTK2B in additional processes, including hypoxia, vascular changes, inflammation, microtubule stabilization and calcium signaling, as potentially relevant to the pathogenesis of LOAD. Reciprocally, these functions can better inform our understanding of the action of NEDD9, CASS4 and PTK2B in cancer.

Overexpression of Nedd9 is a prognostic marker of human gastric cancer

The present study was designed to evaluate the expression and prognostic significance of neural precursor cell-expressed, developmentally downregulated 9 (Nedd9) in patients with gastric cancer. Overexpression of Nedd9 was detected in a number of human cancers and was associated with progression and poor prognosis of the diseases. The expression of Nedd9 and focal adhesion kinase (FAK) were detected using the tissue microarray technique and immunohistochemical method and compared with clinicopathological parameters of patients with gastric cancer. The expressions of Nedd9 and FAK were upregulated in gastric cancer lesions compared with their expression in adjacent non-malignant tissues. High expression of Nedd9 correlated with age, location of tumor, tumor size, depth of invasion, vessel invasion, lymph node metastasis, and distant metastasis, and also with expression of FAK. Further, multivariate analysis suggested that expression of Nedd9 and FAK were independent prognostic indicators for gastric cancer. Cumulative 5-year survival rates of patients with high expression of both Nedd9 and FAK was significantly lower than those with low expression of both. Nedd9 was implicated in the progression of gastric cancer. Based on the TNM stage, Nedd9 and FAK proteins could be useful prognostic marker to predict tumor progression and prognosis in gastric cancer.

The overexpression of scaffolding protein NEDD9 promotes migration and invasion in cervical cancer via tyrosine phosphorylated FAK and SRC

NEDD9, a focal adhesion scaffolding protein, has been recently proposed to regulate invasion and metastasis in some cancer types, but unknown in cervical cancer. The aim of this study was to determine if NEDD9 was involved in the progression and metastasis of cervical cancer. The experimental results showed NEDD9 protein was overexpressed in cervical cancer compared with normal cervical epithelium tissues. Overexpression of NEDD9 was correlated with histological grading, lymph node metastasis, and FIGO stage of cervical cancer. Silencing NEDD9 resulted in tyrosine dephosphorylation of FAK and SRC oncoproteins, and decreased cell migration and invasion in the cervical carcinoma SiHa and HeLa cells. Overexpression of NEDD9 led to tyrosine phosphorylation of FAK and SRC oncoproteins, and increased cell migration and invasion. Moreover, tyrosine phosphorylation of NEDD9 was significantly decreased via suppressing tyrosine phosphorylation of FAK or SRC, suggesting a positive feedback loop of tyrosine phosphorylation between NEDD9 and FAK or SRC. In addition, our data showed that silencing NEDD9 decreased Vimentin expression and increased E-cadherin expression in cervical cancer cells, and vice versa. E-cadherin was subject to regulation of NEDD9, FAK and SRC, but altered neither tyrosine-phosphorylated nor total NEDD9. Our findings suggest that NEDD9 is overexpressed in cervical cancer tissues and cells, and overexpressed NEDD9 promotes migration and invasion in cervical carcinoma cells, probably via a positive feedback loop of tyrosine phosphorylation between NEDD9 and FAK or SRC.

ZNF-mediated resistance to imatinib mesylate in gastrointestinal stromal tumor

Although imatinib mesylate (IM) has transformed the treatment of gastrointestinal stromal tumors (GIST), many patients experience primary/secondary drug resistance. In a previous study, we identified a gene signature, consisting mainly of Kruppel-associated box (KRAB) domain containing zinc finger (ZNF) transcriptional repressors that predict short-term response to IM. To determine if these genes have functional significance, a siRNA library targeting these genes was constructed and applied to GIST cells in vitro. These screens identified seventeen “IM sensitizing genes” in GIST cells (sensitization index (SI) <0.85 ratio of drug/vehicle) with a false discovery rate (FDR) <15%, including twelve ZNF genes, the majority of which are located within the HSA19p12–13.1 locus. These genes were shown to be highly specific to IM and another tyrosine kinase inhibitor (TKI), sunitinib, in GIST cells. In order to determine mechanistically how these ZNFs might be modulating response to IM, RNAi approaches were used to individually silence genes within the predictive signature in GIST cells and expression profiling was performed. Knockdown of the 14 IM-sensitizing genes (10 ZNFs) universally led to downregulation of six genes, including TGFb3, periostin, and NEDD9. These studies implicate a role of KRAB-ZNFs in modulating response to TKIs in GIST.

NEDD9 rs760678 polymorphism and the risk of Alzheimer's disease: a meta-analysis

The NEDD9 rs760678 polymorphism has been extensively investigated for association to Alzheimer's disease (AD), however, results of different studies have been inconsistent. The objective of this study is to assess the relationship of NEDD9 rs760678 polymorphism and AD risk by using meta-analysis. Systematic searches of electronic databases Pubmed and Embase, as well as hand searching of the references of identified articles were performed. Statistical analyses were performed using software Revman 4.2 and STATA 11.0. A total of 4436 cases and 4420 controls in 11 case-control studies were included. The results indicated that the homozygote GG had a 13% decreased risk of AD, when compared with the C allele carriers (CC+CG) (OR=0.87, 95%CI=0.77-0.99, P=0.04 for GG vs. CG+CC). In the subgroup analysis by ethnicity, significant decreased risk was associated with homozygote GG or G allele carriers in Caucasians (OR=0.84, 95%CI=0.74-0.96, P=0.008 for GG vs. CG+CC; OR=0.79, 95%CI=0.69-0.91, P=0.001 for GG vs. CC; OR=0.90, 95%CI=0.84-0.96, P=0.002 for G vs. C), but not in Asians. This meta-analysis suggests that the GG genotype of NEDD9 rs760678 polymorphism would be a protective factor for AD in Caucasians but not in Asians. To further evaluate the effect of gene-gene and gene-environmental interactions between NEDD9 rs760678 polymorphism and the risk of AD, more studies with larger number of subjects are required.

NEDD9 gene polymorphism influences the risk of Alzheimer disease and cognitive function in Chinese older persons

Neural precursor cell expressed, developmentally down-regulated (NEDD9) gene was a new candidate risk gene for Alzheimer disease (AD). The CC genotype of a single nucleotide polymorphism rs760678 within this gene was associated with increasing risk of AD in a large study with white population. Our study aimed to replicate the initial report in Chinese population and explore its effect on cognitive performance. A total of 262 patients with AD, 293 patients with mild cognitive impairment, and 434 cognitive intact controls were recruited in the study. The result showed that G allele had a greater risk of AD (χ for trend test=5.61, df 1, P=0.018). The effects were mainly observed among Apolipoprotein E (APOE) ε4 noncarriers (χ for trend test=4.30, df 1, P=0.038). After adjustment of sex, age, education year, and APOE ε4 status by logistic regression, significant association between NEDD9 GG genotype and AD remained [OR=2.04, 95% confidence interval (CI)=1.02-4.08, P=0.044]. The scores of Cantonese version of the Mini-mental State Examination and Alzheimer's Disease Assessment Subscale-Cognitive subscale were associated with N polymorphism after adjusting for sex, age, education year, and ApoE ε4 status (Linear regression model, P<0.05). Our study identified rs760678 within NEDD9 gene in association with the risk of AD and cognitive performance in Chinese older persons. The fact that different alleles accounted for the risk in different population might suggest that there were ethnic group specific haplotypes that were primarily responsible for the predisposition.

Chronic stress and impaired glutamate function elicit a depressive-like phenotype and common changes in gene expression in the mouse frontal cortex

Major depression might originate from both environmental and genetic risk factors. The environmental chronic mild stress (CMS) model mimics some environmental factors contributing to human depression and induces anhedonia and helplessness. Mice heterozygous for the synaptic vesicle protein (SVP) vesicular glutamate transporter 1 (VGLUT1) have been proposed as a genetic model of deficient glutamate function linked to depressive-like behaviour. Here, we aimed to identify, in these two experimental models, gene expression changes in the frontal cortex, common to stress and impaired glutamate function. Both VGLUT1(+/-) and CMS mice showed helpless and anhedonic-like behavior. Microarray studies in VGLUT1(+/-) mice revealed regulation of genes involved in apoptosis, neurogenesis, synaptic transmission, protein metabolic process or learning and memory. In addition, RT-PCR studies confirmed gene expression changes in several glutamate, GABA, dopamine and serotonin neurotransmitter receptors. On the other hand, CMS affected the regulation of 147 transcripts, some of them involved in response to stress and oxidoreductase activity. Interestingly, 52 genes were similarly regulated in both models. Specifically, a dowregulation in genes that promote cell proliferation (Anapc7), cell growth (CsnK1g1), cell survival (Hdac3), and inhibition of apoptosis (Dido1) was observed. Genes linked to cytoskeleton (Hspg2, Invs), psychiatric disorders (Grin1, MapK12) or an antioxidant enzyme (Gpx2) were also downregulated. Moreover, genes that inhibit the MAPK pathways (Dusp14), stimulate oxidative metabolism (Eif4a2) and enhance glutamate transmission (Rab8b) were upregulated. We suggest that these genes could form part of the altered "molecular context" underlying depressive-like behaviour in animal models. The clinical relevance of these findings is discussed.

NEDD9 is genetically associated with Alzheimer's disease in a Han Chinese population

Neural precursor cell-expressed, developmentally downregulated 9 (NEDD9) has been suspected to be associated with Alzheimer's disease (AD) through participating in the formation of neurite-like membrane extensions and neurite outgrowth to affect the number of neuronal cells/synapses in the brain under stressful conditions. A recent large-scale, multi-tiered association study has identified significant association of a common single nucleotide polymorphism (SNP) rs760678 in the NEDD9 gene with predisposition to late-onset Alzheimer's disease (LOAD) in Caucasians. In order to evaluate the involvement of the NEDD9 polymorphism in the risk of sporadic LOAD, we performed an independent case-control association study to analyze the genotype and allele distributions of the NEDD9 rs760678 polymorphism in a Han Chinese population (383 LOAD cases and 369 healthy controls). There were significant differences in genotype and allele frequencies between LOAD cases and controls (genotype P=0.003, allele P=0.002). After stratification by APOE ε4-carrying status, the C allele of rs760678 was only significantly associated with LOAD in non-APOE ε4 allele carriers (OR=1.43, 95%, CI=1.06-1.94, P=0.024). In addition, a logistic regression analysis also conferred positive association between the SNP rs760678 and LOAD (dominant model: OR=2.10, 95% CI=1.23-3.58, P=0.007; additive model: OR=1.37, 95% CI=1.09-1.74, P=0.008) after adjustment for age, gender, and the APOE ε4 carrier status. The study demonstrated a significant association between the tested SNP and LOAD, indicating that NEDD9 polymorphism has a possible role in changing the genetic susceptibility to LOAD in a Han Chinese population.

Human enhancer of filamentation 1 Is a mediator of hypoxia-inducible factor-1alpha-mediated migration in colorectal carcinoma cells

Human enhancer of filamentation 1 (HEF1; also known as NEDD9 or Cas-L) is a scaffolding protein that is implicated in regulating diverse cellular processes, such as cellular attachment, motility, cell cycle progression, apoptosis, and inflammation. Here, we identify HEF1 as a novel hypoxia-inducible factor-1alpha (HIF-1alpha)-regulated gene and reveal that HEF1 mediates hypoxia-induced migration of colorectal carcinoma cells. HEF1 is highly expressed in cultured colorectal carcinoma cells exposed to hypoxia and in the hypoxic areas of human colorectal cancer (CRC) specimens. Moreover, our data show that HIF-1alpha mediates the effects of hypoxia on induction of HEF1 expression via binding to a hypoxia-responsive element of the HEF1 promoter. Importantly, the induction of HEF1 expression significantly enhances hypoxia-stimulated HIF-1alpha transcriptional activity by modulating the interaction between HIF-1alpha and its transcriptional cofactor p300. Inhibition of HEF1 expression also reduced the levels of hypoxia-inducible genes, including those that regulate cell motility. Cell migration was reduced dramatically following knockdown of HEF1 expression under hypoxic conditions. Thus, this positive feedback loop may contribute to adaptive responses of carcinoma cells encountering hypoxia during cancer progression.

Different implication of NEDD9 genetic variant in early and late-onset Alzheimer's disease

Alzheimer's disease (AD) is a complex and multifactorial progressive neurodegenerative disease. Recently, two studies reported inconsistent results on a possible involvement of the NEDD9 (neural precursor cell expressed, developmentally down-regulated 9, 6p25-p24) as a candidate gene for the risk of developing AD and/or Parkinson's disease (PD). We analyzed the distribution of the rs760678 SNP polymorphism in 735 Italian subjects: 214 unrelated sporadic late-onset AD patients (LOAD, 64.5% females, mean age-at-onset 71.8+/-5.2 years), 135 early-onset AD patients (EOAD, 57.3% females, mean age-at-onset 57.5+/-5.5 years) and 386 healthy controls (68.9% females, mean age 83.4+/-17.9 years; SD). We observed a statistically significant difference between LOAD patients and controls according to genotypes (P=0.016) and allele frequency (P=0.007); CC genotype was more frequent in LOAD cases (44.4%) than controls (36.0%). No difference after stratification of the data in terms of gender and status of the APOE epsilon4 allele was observed. In conclusion, our data do support an implication of the NEDD9 allelic variant in late-onset AD, with an independent effect of the apolipoprotein E (APOE) epsilon4 allele in the risk of developing AD.

CAS proteins in normal and pathological cell growth control

Proteins of the CAS (Crk-associated substrate) family (BCAR1/p130Cas, NEDD9/HEF1/Cas-L, EFS/SIN and CASS4/HEPL) are integral players in normal and pathological cell biology. CAS proteins act as scaffolds to regulate protein complexes controlling migration and chemotaxis, apoptosis, cell cycle, and differentiation, and have more recently been linked to a role in progenitor cell function. Reflecting these complex functions, over-expression of CAS proteins has now been strongly linked to poor prognosis and increased metastasis in cancer, as well as resistance to first-line chemotherapeutics in multiple tumor types including breast and lung cancers, glioblastoma, and melanoma. Further, CAS proteins have also been linked to additional pathological conditions including inflammatory disorders, Alzheimer's and Parkinson's disease, as well as developmental defects. This review will explore the roles of the CAS proteins in normal and pathological states in the context of the many mechanistic insights into CAS protein function that have emerged in the past decade.

Association study of the NEDD9 gene with the risk of developing Alzheimer's and Parkinson's disease

Alzheimer's disease (AD) and Parkinson's disease (PD), the two most common neurodegenerative disorders in the elderly, have been hypothesized to share genetic determinants. Recently, Li et al. proposed that a variant in the NEDD9 gene may be one of these common genetic factors. We attempted to confirm this initial observation by conducting an equivalent analysis in terms of pathologies and sample size. We genotyped the NEDD9 rs760678 SNP in three independent AD case-control studies (n = 3176) and two independent PD case-control studies (n = 1855). However, we failed to detect an association of this SNP with the risk of developing AD or PD, in any of these populations. In conclusion, these data indicate that the rs760678 SNP of the NEDD9 gene is at best a weak genetic determinant of AD or PD.

atRA Regulation of NEDD9, a gene involved in neurite outgrowth and cell adhesion

We previously identified NEDD9 (RAINB2/HEF1/Cas-L) as a new downstream target of all-trans retinoic acid (atRA) and its receptors in the human neuroblastoma cell line, SH-SY5Y [R.A. Merrill, A.W.-M. See, M.L. Wertheim, M. Clagett-Dame, Dev. Dyn. 231 (2004) 564-575; R.A. Merrill, J.M. Ahrens, M.E. Kaiser, K.S. Federhart, V.Y. Poon, M. Clagett-Dame, Biol. Chem. 385 (2004) 605-614]. We now provide functional evidence that NEDD9 is directly regulated by atRA through a complex retinoic acid response element (RARE) located in the NEDD9 proximal promoter and consisting of four conserved half-sites separated by 1, 5, and 1 intervening base pairs. We show that a region of the human NEDD9 promoter from -1670 to +15 is sufficient to confer atRA-responsiveness and that a complex RARE located from -475 to -445 is necessary for this effect. While mutation of any one half-site does not eliminate complex formation in electrophoretic mobility shift assays (EMSA); these same mutations, when tested in transient transfection assays, markedly decrease atRA-responsiveness. Finally, chromatin immunoprecipitation (ChIP) assays demonstrate that RAR and RXR are bound to the RARE in cells.

Epigenetic regulation of BMP7 in the regenerative response to ischemia

Kidneys damaged by ischemia have the potential to regenerate through a mechanism involving intrarenal induction of protective factors, including bone morphogenetic protein-7 (BMP7). Epigenetic changes, such as alterations in histone modifications, have also been shown to play a role in various pathologic conditions, but their involvement in ischemic injury and regeneration remains unknown. This study investigated whether changes in histone acetylation, regulated by histone acetyltransferase and histone deacetylase (HDAC), are induced by renal ischemia and involved in the regenerative response. Ischemia/reperfusion of the mouse kidney induced a transient decrease in histone acetylation in proximal tubular cells, likely as a result of a decrease in histone acetyltransferase activity as suggested by experiments with energy-depleted renal epithelial cells in culture. During recovery after transient energy depletion in epithelial cells, the HDAC isozyme HDAC5 was selectively downregulated in parallel with the return of acetylated histone. Knockdown of HDAC5 by RNAi significantly increased histone acetylation and BMP7 expression. BMP7 induction and HDAC5 downregulation in the recovery phase were also observed in proximal tubular cells in vivo after transient ischemia. These data indicate that ischemia induces dynamic epigenetic changes involving HDAC5 downregulation, which contributes to histone re-acetylation and BMP7 induction in the recovery phase. This highlights HDAC5 as a modulator of the regenerative response after ischemia and suggests HDAC5 inhibition may be a therapeutic strategy to enhance BMP7 expression.

Evidence that common variation in NEDD9 is associated with susceptibility to late-onset Alzheimer's and Parkinson's disease

Late-onset Alzheimer's disease (LOAD) and Parkinson's disease (PD) are the most common neurodegenerative disorders and in both diseases susceptibility is known to be influenced by genes. We set out to identify novel susceptibility genes for LOAD by performing a large scale, multi-tiered association study testing 4692 single nucleotide polymorphism (SNPs). We identified a SNP within a putative transcription factor binding site in the NEDD9 gene (neural precursor cell expressed, developmentally down-regulated), that shows good evidence of association with disease risk in four out of five LOAD samples [N = 3521, P = 5.38x10(-6), odds ratio (OR) = 1.38 (1.20-1.59)] and in addition, we observed a similar pattern of association in two PD sample sets [N = 1464, P = 0.0145, OR =1.31 (1.05-1.62)]. In exploring a potential mechanism for the association, we observed that expression of NEDD9 and APOE show a strong inverse correlation in the hippocampus of Alzheimer's cases. These data implicate NEDD9 as a novel susceptibility gene for LOAD and possibly PD.

A new central scaffold for metastasis: parsing HEF1/Cas-L/NEDD9

Greater understanding of metastasis is required to improve cancer treatment outcomes. Recently, changes in expression of the scaffold protein HEF1/CAS-L/NEDD9 were found to be a potent prometastatic stimulus in melanoma and other cancers. Mechanistic studies suggest diverse cellular roles of HEF1 and highlight its importance in the response to extracellular cues that drive invasion and metastasis. As a metastatic "hub" for signaling in cancer, HEF1 may provide a useful target for drug discovery efforts.

Molecular basis for HEF1/NEDD9/Cas-L action as a multifunctional co-ordinator of invasion, apoptosis and cell cycle

Upregulation of the scaffolding protein HEF1, also known as NEDD9 and Cas-L, has recently been identified as a pro-metastatic stimulus in a number of different solid tumors, and has also been strongly associated with pathogenesis of BCR-Abl-dependent tumors. As the evidence mounts for HEF1/NEDD9/Cas-L as a key player in metastatic cancer, it is timely to review the molecular regulation of HEF1/NEDD9/Cas-L. Most of the mortality associated with cancer arises from uncontrolled metastases, thus a better understanding of the properties of proteins specifically associated with promotion of this process may yield insights that improve cancer diagnosis and treatment. In this review, we summarize the extensive literature regarding HEF1/NEDD9/Cas-L expression and function in signaling relevant to cell attachment, migration, invasion, cell cycle, apoptosis, and oncogenic signal transduction. The complex function of HEF1/NEDD9/Cas-L revealed by this analysis leads us to propose a model in which alleviation of cell cycle checkpoints and acquired resistance to apoptosis is permissive for a HEF1/NEDD9/Cas-L-promoted pro-metastatic phenotype.

Crk-associated substrate lymphocyte type regulates transforming growth factor-beta signaling by inhibiting Smad6 and Smad7

Crk-associated substrate lymphocyte type (Cas-L) is a 105 kDa docking protein with diverse functional properties, including regulation of cell division, proliferation, migration and adhesion. Cas-L is also involved in beta1 integrin- or antigen receptor-mediated signaling in B and T cells. In the present study, we demonstrate that Cas-L potentiates transforming growth factor-beta (TGF-beta) signaling pathway by interacting with Smad6 and Smad7. Immunoprecipitation experiments reveal that single domain deletion of full-length Cas-L completely abolishes its docking function with Smad6 and Smad7, suggesting that the natural structure of Cas-L is necessary for its association with Smad6 and Smad7. On the other hand, both N-terminal and C-terminal deletion mutants of Smad6 and Smad7 still retain their docking ability to Cas-L, suggesting that Smad6 and Smad7 possess several binding motifs to Cas-L. Moreover, Cas-L interaction with Mad-homology (MH)2 domain, but not with MH1 domain of Smad6 or Smad7, ameliorates TGF-beta-induced signaling pathway. Finally, depletion of Cas-L by small-interfering RNA oligo attenuates TGF-beta-induced growth inhibition of Huh-7 cells, with a concomitant reduction in phosphorylation of Smad2 and Smad3. These results strongly suggest that Cas-L is a potential regulator of TGF-beta signaling pathway.