Regulation Of Neuronal Development Research Articles

High-throughput sequencing analysis of differential microRNA expression in the process of blocking the progression of chronic atrophic gastritis to gastric cancer by Xianglian Huazhuo formula.

To explore the mechanism of Xianglian Huazhuo formula (, XLHZ) blocking the development of chronic atrophic gastritis (CAG) to gastric cancer (GC) through bioinformatics analysis and in vitro. Pathological morphology of gastric mucosa of rats were observed. High-throughput sequencing was used to analyze the miRNA expression profile of gastric mucosa. The miRanda, miRDB and miRWalk databases were used to predict the differential target genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed for differential target genes. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to verify the differentially expressed miRNAs and target genes. Western blot, EdU, wound healing and flow cytometry were used to observe the effect of XLHZ on epithelial-mesenchymal transition (EMT) markers, proliferation, migration, apoptosis and cell cycle of CAG cells in vitro. A total of five differentially expressed miRNAs and four differential target genes were screened in this study. GO analysis showed that the target genes were enriched in regulation of neuron development, regulation of transcription factor activity and regulation of RNA polymerase. KEGG pathways database differences in gene enrichment of target genes in the Wnt signaling pathway, Phospholipase D signaling pathway and mitogen-activated protein kinase signaling pathway. qRT-PCR confirmed that miRNAs and its target genes were consistent with the screening results. In vitro, our study revealed that XLHZ could increase the expression of E-cadherin, decrease the expression of transforming growth factor β1, vimentin and β-catenin, inhibite the proliferation and migration of CAG cells, cause cell cycle arrest at G0/G1 and G2/M phase, induce the apoptosis of CAG cells, and prevent the progression of CAG to GC. This study provided a new idea for the mechanism of blocking the progression of CAG to GC by XLHZ, which may be related to the expression of miR-20a-3p, miR-320-3p, miR-34b-5p, miR-483-3p and miR-883-3p and their target genes transferrin receptor, nuclear receptor subfamily 4 member 2, delta like canonical Notch ligand 1 and a kinase anchor protein 12 in CAG. In the future, we will continue to investigate the linkage between the active ingredients of XLHZ and the relevant miRNAs and their target genes, so as to provide more sufficient experimental basis for clinically effective prevention of CAG to GC.

The evolution of mammalian Rem2: unraveling the impact of purifying selection and coevolution on protein function, and implications for human disorders.

Rad And Gem-Like GTP-Binding Protein 2 (Rem2), a member of the RGK family of Ras-like GTPases, is implicated in Huntington's disease and Long QT Syndrome and is highly expressed in the brain and endocrine cells. We examine the evolutionary history of Rem2 identified in various mammalian species, focusing on the role of purifying selection and coevolution in shaping its sequence and protein structural constraints. Our analysis of Rem2 sequences across 175 mammalian species found evidence for strong purifying selection in 70% of non-invariant codon sites which is characteristic of essential proteins that play critical roles in biological processes and is consistent with Rem2's role in the regulation of neuronal development and function. We inferred epistatic effects in 50 pairs of codon sites in Rem2, some of which are predicted to have deleterious effects on human health. Additionally, we reconstructed the ancestral evolutionary history of mammalian Rem2 using protein structure prediction of extinct and extant sequences which revealed the dynamics of how substitutions that change the gene sequence of Rem2 can impact protein structure in variable regions while maintaining core functional mechanisms. By understanding the selective pressures, protein- and gene - interactions that have shaped the sequence and structure of the Rem2 protein, we gain a stronger understanding of its biological and functional constraints.

EMX2 inhibits clear cell renal cell carcinoma progress via modulating Akt/FOXO3a pathway.

Empty spiracles homeobox 2 (EMX2)is initially identified as a key transcription factor that plays an essential role in the regulation of neuronal development and some brain disorders. Recently, several studies emphasized thatEMX2 could as a tumor suppressor, but its role in human clear cell renal cell carcinoma (ccRCC) remains unclear. In the present study, we investigated the role and underlying mechanism of EMX2 in the regulation of ccRCC progress. Our results demonstrated that EMX2 expression was markedly decreased in ccRCC tissues and cell lines, and low EMX2 expression predicted the poor prognosis of ccRCC patients. In addition, forced expression of EMX2 significantly inhibited the cell growth, migration, and invasion in vitro, as well as ccRCC tumor growth in nude mice, via, at least in part, regulating Akt/FOXO3a pathway. In detail, EMX2 could attenuate the phosphorylation levels of Akt and FOXO3a, and increase FOXO3a expression without affecting total Akt expression in vivo and in vitro. Meanwhile, shRNA-mediated knockdown of FOXO3a expression could obviously attenuate the effects of EMX2 on cell growth, migration, invasion, and tumor growth. Furthermore, EMX2 could significantly attenuate the interaction between Akt and FOXO3a. Taken together, our results demonstrated that EMX2 could inhibit ccRCC progress through, at least in part, modulating Akt/FOXO3a signaling pathway, thus representing a novel role and underlying mechanism of EMX2 in the regulation of ccRCC progress.

Short- and Long-Term Regulation of HuD: A Molecular Switch Mediated by Folic Acid?

The RNA-binding protein HuD has been shown to play a crucial role in gene regulation in the nervous system and is involved in various neurological and psychiatric diseases. In this study, through the creation of an interaction network on HuD and its potential targets, we identified a strong association between HuD and several diseases of the nervous system. Specifically, we focused on the relationship between HuD and the brain-derived neurotrophic factor (BDNF), whose protein is implicated in several neuronal diseases and is involved in the regulation of neuronal development, survival, and function. To better investigate this relationship and given that we previously demonstrated that folic acid (FA) is able to directly bind HuD itself, we performed in vitro experiments in neuron-like human SH-SY5Y cells in the presence of FA, also known to be a pivotal environmental factor influencing the nervous system development. Our findings show that FA exposure results in a significant increase in both HuD and BDNF transcripts and proteins after 2 and 4 h of treatment, respectively. Similar data were obtained after 2 h of FA incubation followed by 2 h of washout. This increase was no longer detected upon 24 h of FA exposure, probably due to a signaling shutdown mechanism. Indeed, we observed that following 24 h of FA exposure HuD is methylated. These findings indicate that FA regulates BDNF expression via HuD and suggest that FA can behave as an epigenetic modulator of HuD in the nervous system acting via short- and long-term mechanisms. Finally, the present results also highlight the potential of BDNF as a therapeutic target for specific neurological and psychiatric diseases.

PCSK9 Involvement in Autism Etiology: Sequence Variations, Protein Concentration, and Promoter Methylation

Besides its main role in the control of blood cholesterol, PCSK9 has a role in the regulation of neuronal development and apoptosis. We suggest, for the first time, the possible involvement of PCSK9 in autism. In this case-control study, Sanger sequencing was used to analyze sequence variations in the PCSK9 gene exons and their flanking intronic sequences. ELISA assay was used to determine the plasma concentration of PCSK9. The methylation percentage of the PCSK9 gene promoter was assessed by methylation-specific PCR (MSP). Forty-three variants were found; out of them, seven showed differential frequency between patients and controls. rs.45448095, rs.45613943, rs.630431, rs.529500286, and rs.45439391 are risk factors for autism, while rs.11800231 and rs.483462 are protective variants. The concentration of plasma PCSK9 protein was significantly elevated and the methylation percentage of PCSK9 gene promoter was significantly lower in cases than in controls (P <0.001 and = 0.002, respectively). ROC curve analysis identified an area under the curve (AUC) of 0.915 for plasma protein concentration and 0.693 for percent gene promoter methylation. In addition, two new variants were identified (g.23809C>T in intron 11 and g.24071T>G in 3' UTR). This is the first study to investigate the correlation between PCSK9 protein and autism and suggests the potential involvement of PCSK9 as one of the susceptibility genes for autism. Further studies with a larger number of subjects are recommended.

IASPP regulates neurite development by interacting with Spectrin proteins.

Since its discovery in 1999, a substantial body of research has shown that iASPP is highly expressed in various kinds of tumors, interacts with p53, and promotes cancer cell survival by antagonizing the apoptotic activity of p53. However, its role in neurodevelopment is still unknown. We studied the role of iASPP in neuronal differentiation through different neuronal differentiation cellular models, combined with immunohistochemistry, RNA interference and gene overexpression, and studied the molecular mechanism involved in the regulation of neuronal development by iASPP through coimmunoprecipitation coupled with mass spectrometry (CoIP-MS) and coimmunoprecipitation (CoIP). In this study, we found that the expression of iASPP gradually decreased during neuronal development. iASPP silencing promotes neuronal differentiation, while its overexpression inhibited neurite differentiation in a variety of neuronal differentiation cellular models. iASPP associated with the cytoskeleton-related protein Sptan1 and dephosphorylated the serine residues in the last spectrin repeat domain of Sptan1 by recruiting PP1. The non-phosphorylated and phosphomimetic mutant form of Sptbn1 inhibited and promoted neuronal cell development respectively. Overall, we demonstrate that iASPP suppressed neurite development by inhibiting phosphorylation of Sptbn1.

Shuttle craft Gene Affects Lifespan of Drosophila melanogaster by Controlling Early Development and Modifying Aging Program.

Fundamental mechanisms underlying genetic control of lifespan are intensively studied and discussed due to the increasing importance of extending healthy human life. The stc gene of the model organism Drosophila melanogaster encodes a transcription factor, homolog of the human transcription factor NF-X1, involved in regulation of neuronal development and other processes, as well as in control of lifespan. In this work, we demonstrate that the stc knockdown in embryonic and nerve cells leads to changes in lifespan, with the nature of changes depending on the cell type and sex of individuals. Based on our results, we suggest that stc gene is involved in transcription regulation throughout life, and, as a result, also affects a complex integral trait, lifespan. At the same time, we show that the reduction of stc expression in neurons can alleviate the negative effect of glutamate on longevity, possibly preventing development of glutamate excitotoxicity, thus modifying the cell death program and preventing death of individuals due to phenoptosis.

Deep proteome profiling reveals signatures of age and sex differences in paw skin and sciatic nerve of naïve mice.

The age and sex of studied animals profoundly impact experimental outcomes in biomedical research. However, most preclinical studies in mice use a wide-spanning age range from 4 to 20 weeks and do not assess male and female mice in parallel. This raises concerns regarding reproducibility and neglects potentially relevant age and sex differences, which are largely unknown at the molecular level in naïve mice. Here, we employed an optimized quantitative proteomics workflow in order to deeply profile mouse paw skin and sciatic nerves (SCN) - two tissues implicated in nociception and pain as well as diseases linked to inflammation, injury, and demyelination. Remarkably, we uncovered significant differences when comparing male and female mice at adolescent (4 weeks) and adult (14 weeks) age. Our analysis deciphered protein subsets and networks that were correlated with the age and/or sex of mice. Notably, among these were proteins/biological pathways with known (patho)physiological relevance, e.g., homeostasis and epidermal signaling in skin, and, in SCN, multiple myelin proteins and regulators of neuronal development. Extensive comparisons with available databases revealed that various proteins associated with distinct skin diseases and pain exhibited significant abundance changes in dependence on age and/or sex. Taken together, our study uncovers hitherto unknown sex and age differences at the level of proteins and protein networks. Overall, we provide a unique proteome resource that facilitates mechanistic insights into somatosensory and skin biology, and integrates age and sex as biological variables - a prerequisite for successful preclinical studies in mouse disease models.

Identifying Immune Cell Infiltration and Effective Diagnostic Biomarkers in Lung Adenocarcinoma by Comprehensive Bioinformatics Analysis and In Vitro Study.

Family with sequence similarity 72B (FAM72B) has been characterized in the regulation of neuronal development. Nevertheless, the prognostic value of FAM72B expression and its function in the immune microenvironment of lung adenocarcinoma (LUAD) currently remains elusive. In this study, by adopting bioinformatics methodology and experimental verification, we found that FAM72B was upregulated in lung cancer tissues and cell lines, and a higher FAM72B level predicted an unfavorable clinical outcome in LUAD patients. The knockdown of FAM72B significantly inhibited cell proliferation, cell migration, and induced cell apoptosis in LUAD. The receiver operating characteristic curve suggested that FAM72B had a high predictive accuracy for the outcomes of LUAD. Kyoto Encyclopedia of Genes and Genomes and Gene Set Enrichment Analyses confirmed that FAM72B-related genes were involved in cell proliferation and immune-response signaling pathway. Moreover, upregulated FAM72B expression was significantly associated with immune cell infiltration in the LUAD tumor microenvironment. Meanwhile, a potential ceRNA network was constructed to identify the lncRNA-AL360270.2/TMPO-AS1/AC125807.2/has-let-7a/7b/7c/7e/7f/FAM72B regulatory axis that regulates FAM72B overexpression in LUAD and is associated with a poor prognosis. We also confirmed that AL360270.2, TMPO-AS1, and AC125807.2 were significantly upregulated in LUAD cell lines than in human bronchial epithelial cells. In conclusion, FAM72B may serve as a novel biomarker in predicting the clinical prognosis and immune status for lung adenocarcinoma.

Role of IL-6 in the regulation of neuronal development, survival and function

The pleiotropic cytokine interleukin-6 (IL-6) is emerging as a molecule with both beneficial and destructive potentials. It can exert opposing actions triggering either neuron survival after injury or causing neurodegeneration and cell death in neurodegenerative or neuropathic disorders. Importantly, neurons respond differently to IL-6 and this critically depends on their environment and whether they are located in the peripheral or the central nervous system. In addition to its hub regulator role in inflammation, IL-6 is recently emerging as an important regulator of neuron function in health and disease, offering exciting possibilities for more mechanistic insight into the pathogenesis of mental, neurodegenerative and pain disorders and for developing novel therapies for diseases with neuroimmune and neurogenic pathogenic components.

Musashi-1-A Stemness RBP for Cancer Therapy?

Simple SummaryMusashi–1 (MSI1) is an RNA–binding protein that promotes stemness properties. It was initially discovered as a regulator of neuronal development and oocyte maturation in flies and frogs. Due to its specific expression pattern with high levels during development and in a variety of cancers, MSI1 evolved as an interesting target for cancer therapy. In cancer cells, the protein mainly promotes an undifferentiated state enhancing cancer growth and therapy resistance. In this review, we summarize previous findings from development of other organisms, outline MSI1′s expression and function in different cancer entities and highlight the development of MSI1–directed inhibitors.The RNA–binding protein Musashi–1 (MSI1) promotes stemness during development and cancer. By controlling target mRNA turnover and translation, MSI1 is implicated in the regulation of cancer hallmarks such as cell cycle or Notch signaling. Thereby, the protein enhanced cancer growth and therapy resistance to standard regimes. Due to its specific expression pattern and diverse functions, MSI1 represents an interesting target for cancer therapy in the future. In this review we summarize previous findings on MSI1′s implications in developmental processes of other organisms. We revisit MSI1′s expression in a set of solid cancers, describe mechanistic details and implications in MSI1 associated cancer hallmark pathways and highlight current research in drug development identifying the first MSI1–directed inhibitors with anti–tumor activity.

Propofol impairs specification of retinal cell types in zebrafish by inhibiting Zisp-mediated Noggin-1 palmitoylation and trafficking

BackgroundPropofol can have adverse effects on developing neurons, leading to cognitive disorders, but the mechanism of such an effect remains elusive. Here, we aimed to investigate the effect of propofol on neuronal development in zebrafish and to identify the molecular mechanism(s) involved in this pathway.MethodsThe effect of propofol on neuronal development was demonstrated by a series of in vitro and in vivo experiments. mRNA injections, whole-mount in situ hybridization and immunohistochemistry, quantitative real-time polymerase chain reaction, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, 5-ethynyl-2′-deoxyuridine labeling, co-immunoprecipitation, and acyl–biotin exchange labeling were used to identify the potential mechanisms of propofol-mediated zisp expression and determine its effect on the specification of retinal cell types.ResultsPropofol impaired the specification of retinal cell types, thereby inhibiting neuronal and glial cell formation in retinas, mainly through the inhibition of Zisp expression. Furthermore, Zisp promoted the stabilization and secretion of a soluble form of the membrane-associated protein Noggin-1, a specific palmitoylation substrate.ConclusionsPropofol caused a severe phenotype during neuronal development in zebrafish. Our findings established a direct link between an anesthetic agent and protein palmitoylation in the regulation of neuronal development. This could be used to investigate the mechanisms via which the improper use of propofol might result in neuronal defects.

An interaction between PRRT2 and Na+/K+ ATPase contributes to the control of neuronal excitability

Mutations in PRoline Rich Transmembrane protein 2 (PRRT2) cause pleiotropic syndromes including benign infantile epilepsy, paroxysmal kinesigenic dyskinesia, episodic ataxia, that share the paroxysmal character of the clinical manifestations. PRRT2 is a neuronal protein that plays multiple roles in the regulation of neuronal development, excitability, and neurotransmitter release. To better understand the physiopathology of these clinical phenotypes, we investigated PRRT2 interactome in mouse brain by a pulldown-based proteomic approach and identified α1 and α3 Na+/K+ ATPase (NKA) pumps as major PRRT2-binding proteins. We confirmed PRRT2 and NKA interaction by biochemical approaches and showed their colocalization at neuronal plasma membrane. The acute or constitutive inactivation of PRRT2 had a functional impact on NKA. While PRRT2-deficiency did not modify NKA expression and surface exposure, it caused an increased clustering of α3-NKA on the plasma membrane. Electrophysiological recordings showed that PRRT2-deficiency in primary neurons impaired NKA function during neuronal stimulation without affecting pump activity under resting conditions. Both phenotypes were fully normalized by re-expression of PRRT2 in PRRT2-deficient neurons. In addition, the NKA-dependent afterhyperpolarization that follows high-frequency firing was also reduced in PRRT2-silenced neurons. Taken together, these results demonstrate that PRRT2 is a physiological modulator of NKA function and suggest that an impaired NKA activity contributes to the hyperexcitability phenotype caused by PRRT2 deficiency.

3D promoter architecture re-organization during iPSC-derived neuronal cell differentiation implicates target genes for neurodevelopmental disorders.

Neurodevelopmental disorders are thought to arise from interrupted development of the brain at an early age. Genome-wide association studies (GWAS) have identified hundreds of loci associated with susceptibility to neurodevelopmental disorders; however, which noncoding variants regulate which genes at these loci is often unclear. To implicate neuronal GWAS effector genes, we performed an integrated analysis of transcriptomics, epigenomics and chromatin conformation changes during the development from Induced pluripotent stem cell-derived neuronal progenitor cells (NPCs) into neurons using a combination of high-resolution promoter-focused Capture-C, ATAC-seq and RNA-seq. We observed that gene expression changes during the NPC-to-neuron transition were highly dependent on both promoter accessibility changes and long-range interactions which connect distal cis-regulatory elements (enhancer or silencers) to developmental-stage-specific genes. These genome-scale promoter-cis-regulatory-element atlases implicated 454 neurodevelopmental disorder-associated, putative causal variants mapping to 600 distal targets. These putative effector genes were significantly enriched for pathways involved in the regulation of neuronal development and chromatin organization, with 27 % expressed in a stage-specific manner. The intersection of open chromatin and chromatin conformation revealed development-stage-specific gene regulatory architectures during neuronal differentiation, providing a rich resource to aid characterization of the genetic and developmental basis of neurodevelopmental disorders.

Sequence Characterization of Forebrain Embryonic Zinc Finger-like (FEZL) Gene in Indian Zebu (Bos indicus) Cattle and their Crossbreds

Background: Forebrain embryonic zinc finger-like (FEZL) gene is an important candidate associated with mastitis resistance in dairy cattle. FEZL is involved in transcriptional regulation of neuronal development and there exists a crosstalk between neuronal development and immunity via downstream cytokine expression. A single glycine insertion into glycine stretch of FEZL gene has large effect on downstream cytokine pathway making the cows susceptible to mastitis. The present study was aimed to sequence characterize FEZL gene in Sahiwal (Bos indicus) and Karan Fries (Bos inidcus X Bos taurus) cattle.Methods: Sequence characterization of bovine FEZL gene was carried out by primer walking method. Ten sets of oligonucleotide primers were designed to synthesize overlapping fragments and generate the complete sequence of about 3.7 kb covering all exons and 5’ upstream regulatory and flanking regions.Result: A total of eight nucleotide variations including three INDELS and five substitution mutations were observed among FEZL gene sequences of Bos taurus, Bos indicus (Sahiwal) and Bos taurus X Bos indicus (Karan Fries) cattle. The conceptualized amino acid sequence of bovine FEZL gene in Sahiwal and Karan Fries cattle was found to have 13 tandem Glycine residues and a serine to proline change within exon 1 region. The percent identity of FEZL gene of Sahiwal and Karan Fries cattle was 99% with that of Bos taurus, 95% with dog, horse and pig, 94% with human, 93% with rabbit, 92% with marmoset, 89% with rat and 79% with chicken. Sequence characterization of ~0.7 kb 5’ flanking region showed that it is highly conserved among bovines and resulted in prediction of six putative sites for binding of transcription factors (including Elk-1, Oct-1, HNF4, Lmo2 complex, GATA-3 and Nkx2-5). Elucidation of Bos indicus FEZL gene will further form the basis to identify candidate gene markers for association with mastitis resistance/susceptibility in cattle.

Downregulation of Brain Enriched Type 2 MAGEs Is Associated With Immune Infiltration and Poor Prognosis in Glioma.

Melanoma associated antigen (MAGE) is an extensively studied family of tumor-associated genes that share a common MAGE homology domain (MHD). Based upon their expression pattern, MAGE genes have been broadly classified into type 1 MAGEs (T1Ms) and type 2 MAGEs (T2Ms) categories. Interestingly, several T2Ms are highly expressed in the brain and involved in the regulation of neuronal development, differentiation, and survival. Available literature suggests possible tumor suppressor functions of a few T2Ms, while information available about their expression, regulation, and clinical significance in glioma is scanty. This prompted us to perform a comprehensive analysis of T2M expression in glioma. Gene expression data from glioma datasets: Oncomine, TCGA, and REMBRANDT study, were used to assess the mRNA expression of T2M genes (MAGED1, MAGED2, MAGED3, MAGED4, MAGED4B, MAGEE1, MAGEE2, MAGEF1, MAGEH1, MAGEL2, NSMCE3, and NDN), and their association with clinical characteristics and composition of the tumor microenvironment. Further, mutation, copy number alteration, and DNA methylation data from TCGA were assessed for determining potential mechanisms of T2Ms expression in glioma. Expression analysis revealed overexpression of MAGED subfamily genes in glioma, while other genes of this family exhibited reduced expression in advanced grades of this malignancy. Further, the expression of T2Ms exhibited varying extent of positive correlations with each other. Amongst downregulated T2Ms, MAGEH1 expression exhibited negative correlations with DNA methylation. Additionally, genes associated with MAGEH1 were enriched in Myc and Hedgehog signaling. Furthermore, T2Ms downregulation was associated with immune infiltration in glioma tissues and poor overall survival of glioma patients. In multivariate Cox regression analysis, MAGEH1 emerged as an independent prognosticator in lower grade glioma. Conclusively, these results suggest that expression of T2Ms is associated with important clinical and molecular features in glioma. Mechanistic studies may further provide novel insights into their role in glioma progression.

Dopamine D3 Receptor Heteromerization: Implications for Neuroplasticity and Neuroprotection.

The dopamine (DA) D3 receptor (D3R) plays a pivotal role in the control of several functions, including motor activity, rewarding and motivating behavior and several aspects of cognitive functions. Recently, it has been reported that the D3R is also involved in the regulation of neuronal development, in promoting structural plasticity and in triggering key intracellular events with neuroprotective potential. A new role for D3R-dependent neurotransmission has thus been proposed both in preserving DA neuron homeostasis in physiological conditions and in preventing pathological alterations that may lead to neurodegeneration. Interestingly, there is evidence that nicotinic acetylcholine receptors (nAChR) located on DA neurons also provide neurotrophic support to DA neurons, an effect requiring functional D3R and suggesting the existence of a positive cross-talk between these receptor systems. Increasing evidence suggests that, as with the majority of G protein-coupled receptors (GPCR), the D3R directly interacts with other receptors to form new receptor heteromers with unique functional and pharmacological properties. Among them, we recently identified a receptor heteromer containing the nAChR and the D3R as the molecular effector of nicotine-mediated neurotrophic effects. This review summarizes the functional and pharmacological characteristics of D3R, including the capability to form active heteromers as pharmacological targets for specific neurodegenerative disorders. In particular, the molecular and functional features of the D3R-nAChR heteromer will be especially discussed since it may represent a possible key etiologic effector for DA-related pathologies, such as Parkinson’s disease (PD), and a target for drug design.

117 Supplementation of IVF medium with nerve growth factor improved bovine embryonic cleavage rates during summer months

Nerve growth factor-β (NGF), a protein originally associated with regulation of neuron development, has been found to play a role in the reproductive system of mammals. Previous research showed that administration of NGF to cows resulted in enhanced conceptus development. Although these effects were speculated to be a result of improved corpus luteum function, whether NGF could act directly on the embryo remained undetermined. Therefore, the direct effects of NGF on fertilization and embryo development warrant investigation to see whether it can be used as a novel tool to improve cleavage and blastocyst rates when producing embryos via IVF during periods of suboptimal oocyte quality, such as with heat stress. The objective of this study was to explore how supplementation of NGF, purified from bull seminal plasma, during IVF may directly affect embryo development in oocytes harvested in the summer. Abattoir-derived bovine ovaries were used for recovery of cumulus-oocyte complexes (COCs) over eight replicates through May and June. On Day −1, COCs were collected and matured for 20h in oocyte maturation medium incubated at 38.5°C. On Day 0, matured oocytes were added to a solution of IVF-Tyrode's albumin lactate pyruvate (TALP) and either phosphate-buffered saline (PBS; control) or 100ngmL−1 NGF. Pooled frozen-thawed semen from two different bulls per replicate were added to the IVF solutions and incubated with COCs for 20h at 38.5°C in a humidified atmosphere of 5% CO2. On Day 1, zygotes were washed in HEPES-TALP, and cumulus cells were removed using 1% hyaluronidase. The zygotes were plated in synthetic oviductal fluid (SOF-BE2) culture medium and incubated at 38.5°C in a tri-gas chamber (5% CO2, 5% O2, and balanced N2). Cleavage rates were recorded at 24 and 48h, calculated by dividing the number of cleaved embryos by the total zygote count. Embryos were incubated until Day 8, when the rate of blastocysts was assessed. This study found that the treatment of IVF medium with NGF increased the cleavage rate of embryos after 48h (Control: 59%; NGF: 66%; P=0.04) and the hatched blastocyst percentage per oocyte on Day 8 (Control: 6.7%; NGF: 9.4%; P=0.01). The treatment did not affect the percentage of blastocysts per cleaved embryos (Control: 21%; NGF: 22%; P=0.16) or the hatched blastocyst rate at Day 8 (Control: 53%; NGF: 55%; P=0.67). These results show that NGF can act directly on the oocyte during fertilization to alter subsequent development, specifically through increased embryonic cleavage rates. Further studies are needed to assess different dosages of NGF in order to mitigate the detrimental effects of heat stress on oocyte competence for use in IVF. Follow-up studies using a whole-animal model are needed to understand the clinical relevance of these findings in the ability of embryos to promote maternal recognition of pregnancy.

Genomic variation in educational attainment modifies Alzheimer disease risk.

ObjectiveTo determine the putative protective relationship of educational attainment on Alzheimer disease (AD) risk using Mendelian randomization and to test the hypothesis that by using genetic regions surrounding individually associated single nucleotide polymorphisms (SNPs) as the instrumental variable, we can identify genes that contribute to the relationship.MethodsWe performed Mendelian randomization using genome-wide association study summary statistics from studies of educational attainment and AD in two stages. Our instrumental variable comprised (1) 1,271 SNPs significantly associated with educational attainment and (2) individual 2-Mb regions surrounding the genome-wide significant SNPs.ResultsA causal inverse relationship between educational attainment and AD was identified by the 1,271 SNPs (odds ratio = 0.63; 95% confidence interval, 0.54–0.74; p = 4.08 x 10−8). Analysis of individual loci identified 2 regions that significantly replicated the causal relationship. Genes within these regions included LRRC2, SSBP2, and NEGR1; the latter a regulator of neuronal growth.ConclusionsEducational attainment is an important protective factor for AD. Genomic regions that significantly paralleled the overall causal relationship contain genes expressed in neurons or involved in the regulation of neuronal development.

SA62 - TRANSCRIPTIONAL CONSEQUENCES OF REDUCED EXPRESSION OF THE SCHIZOPHRENIA SUSCEPTIBILITY GENE SETD1A

Background Loss of function alleles in SETD1A are a genetic risk factor for developing schizophrenia. SETD1A encodes a protein possessing histone methyltransferase activity. Specifically, it catalyses the methylation of histone H3 at Lys4, a modification indicative of active regulatory DNA function. Reduced SETD1A expression is therefore likely to have a major impact on global gene expression via alterations to the histone code. To understand the downstream genes and pathways altered by SETD1A expression we performed gene expression profiling of a neural cell line in which SETD1A expression had been reduced. Methods SETD1A expression was reduced in the SH-SY5Y neuroblastoma cell line using two non-overlapping siRNAs. A non-targeting siRNA was used as a control. Four days after transfection cells were harvested for RNA extraction. Transcriptional profiling was performed using Illumina microarrays. Differential expressed probes were identified using t tests and gene ontology enrichment analysis performed using DAVID. Quantitative PCR was used to verify the microarray findings for a subset of gene transcripts. We tested for enrichment of association with schizophrenia amongst the differential expressed probes using MAGMA. Results Both targeting siRNAs reduced SETD1A RNA expression ~50% compared to control. Gene expression profiling identified 1131 differentially expressed probes (p Discussion Reduced SETD1A levels lead to widespread changes in the expression of genes involved in diverse process, consistent with its role in general transcription. However, we observed altered expression of known regulators of neuronal development and function. Our results also highlight mitochondrial function as important downstream consequences of reduced SETD1A expression. Importantly, we show that gene expression changes after knock-down of a rare variant schizophrenia risk gene are enriched for a common variant association signal, indicating a point of molecular convergence in risk mechanisms.