ABSTRACT
MOTIVATION: Since early 2020, the coronavirus disease 2019 (COVID-19) pandemic has confronted the biomedical community with an unprecedented challenge. The rapid spread of COVID-19 and ease of transmission seen worldwide is due to increased population flow and international trade. Front-line medical care, treatment research and vaccine development also require rapid and informative interpretation of the literature and COVID-19 data produced around the world, with 177 500 papers published between January 2020 and November 2021, i.e. almost 8500 papers per month. To extract knowledge and enable interoperability across resources, we developed the COVID-19 Vocabulary (COVoc), an application ontology related to the research on this pandemic. The main objective of COVoc development was to enable seamless navigation from biomedical literature to core databases and tools of ELIXIR, a European-wide intergovernmental organization for life sciences. RESULTS: This collaborative work provided data integration into SIB Literature services, an application ontology (COVoc) and a triage service named COVTriage and based on annotation processing to search for COVID-related information across pre-defined aspects with daily updates. Thanks to its interoperability potential, COVoc lends itself to wider applications, hopefully through further connections with other novel COVID-19 ontologies as has been established with Coronavirus Infectious Disease Ontology. AVAILABILITY AND IMPLEMENTATION: The data at https://github.com/EBISPOT/covoc and the service at https://candy.hesge.ch/COVTriage.
Subject(s)
COVID-19 , Humans , COVID-19/diagnosis , Triage , Commerce , InternationalityABSTRACT
Open Targets Genetics (https://genetics.opentargets.org) is an open-access integrative resource that aggregates human GWAS and functional genomics data including gene expression, protein abundance, chromatin interaction and conformation data from a wide range of cell types and tissues to make robust connections between GWAS-associated loci, variants and likely causal genes. This enables systematic identification and prioritisation of likely causal variants and genes across all published trait-associated loci. In this paper, we describe the public resources we aggregate, the technology and analyses we use, and the functionality that the portal offers. Open Targets Genetics can be searched by variant, gene or study/phenotype. It offers tools that enable users to prioritise causal variants and genes at disease-associated loci and access systematic cross-disease and disease-molecular trait colocalization analysis across 92 cell types and tissues including the eQTL Catalogue. Data visualizations such as Manhattan-like plots, regional plots, credible sets overlap between studies and PheWAS plots enable users to explore GWAS signals in depth. The integrated data is made available through the web portal, for bulk download and via a GraphQL API, and the software is open source. Applications of this integrated data include identification of novel targets for drug discovery and drug repurposing.
Subject(s)
Databases, Genetic , Genome, Human , Inflammatory Bowel Diseases/genetics , Molecular Targeted Therapy/methods , Quantitative Trait Loci , Software , Chromatin/chemistry , Chromatin/metabolism , Datasets as Topic , Drug Discovery/methods , Drug Repositioning/methods , Genome-Wide Association Study , Genotype , Humans , Inflammatory Bowel Diseases/drug therapy , Inflammatory Bowel Diseases/metabolism , Inflammatory Bowel Diseases/pathology , Internet , Phenotype , Quantitative Trait, HeritableABSTRACT
In biology and biomedicine, relating phenotypic outcomes with genetic variation and environmental factors remains a challenge: patient phenotypes may not match known diseases, candidate variants may be in genes that haven't been characterized, research organisms may not recapitulate human or veterinary diseases, environmental factors affecting disease outcomes are unknown or undocumented, and many resources must be queried to find potentially significant phenotypic associations. The Monarch Initiative (https://monarchinitiative.org) integrates information on genes, variants, genotypes, phenotypes and diseases in a variety of species, and allows powerful ontology-based search. We develop many widely adopted ontologies that together enable sophisticated computational analysis, mechanistic discovery and diagnostics of Mendelian diseases. Our algorithms and tools are widely used to identify animal models of human disease through phenotypic similarity, for differential diagnostics and to facilitate translational research. Launched in 2015, Monarch has grown with regards to data (new organisms, more sources, better modeling); new API and standards; ontologies (new Mondo unified disease ontology, improvements to ontologies such as HPO and uPheno); user interface (a redesigned website); and community development. Monarch data, algorithms and tools are being used and extended by resources such as GA4GH and NCATS Translator, among others, to aid mechanistic discovery and diagnostics.
Subject(s)
Computational Biology/methods , Genotype , Phenotype , Algorithms , Animals , Biological Ontologies , Databases, Genetic , Exome , Genetic Association Studies , Genetic Variation , Genomics , Humans , Internet , Software , Translational Research, Biomedical , User-Computer InterfaceABSTRACT
Transplantation of dopaminergic neurons can potentially improve the clinical outcome of Parkinson's disease, a neurological disorder resulting from degeneration of mesencephalic dopaminergic neurons. In particular, transplantation of embryonic-stem-cell-derived dopaminergic neurons has been shown to be efficient in restoring motor symptoms in conditions of dopamine deficiency. However, the use of pluripotent-derived cells might lead to the development of tumours if not properly controlled. Here we identified a minimal set of three transcription factors--Mash1 (also known as Ascl1), Nurr1 (also known as Nr4a2) and Lmx1a--that are able to generate directly functional dopaminergic neurons from mouse and human fibroblasts without reverting to a progenitor cell stage. Induced dopaminergic (iDA) cells release dopamine and show spontaneous electrical activity organized in regular spikes consistent with the pacemaker activity featured by brain dopaminergic neurons. The three factors were able to elicit dopaminergic neuronal conversion in prenatal and adult fibroblasts from healthy donors and Parkinson's disease patients. Direct generation of iDA cells from somatic cells might have significant implications for understanding critical processes for neuronal development, in vitro disease modelling and cell replacement therapies.
Subject(s)
Cell Differentiation , Cellular Reprogramming , Dopamine/metabolism , Fibroblasts/cytology , Neurons/cytology , Neurons/metabolism , Action Potentials , Animals , Animals, Newborn , Basic Helix-Loop-Helix Transcription Factors/genetics , Basic Helix-Loop-Helix Transcription Factors/metabolism , Cell Differentiation/genetics , Cell Differentiation/physiology , Cells, Cultured , Cellular Reprogramming/genetics , Cellular Reprogramming/physiology , Embryo, Mammalian/cytology , Fibroblasts/metabolism , Gene Expression Profiling , Homeodomain Proteins/genetics , Homeodomain Proteins/metabolism , Humans , LIM-Homeodomain Proteins , Mice , Nuclear Receptor Subfamily 4, Group A, Member 2/genetics , Nuclear Receptor Subfamily 4, Group A, Member 2/metabolism , Oligonucleotide Array Sequence Analysis , Parkinson Disease/pathology , Patch-Clamp Techniques , Regenerative Medicine , Skin/cytology , Transcription FactorsABSTRACT
BACKGROUND: People with an autistic spectrum disorder (ASD) display a variety of characteristic behavioral traits, including impaired social interaction, communication difficulties and repetitive behavior. This complex neurodevelopment disorder is known to be associated with a combination of genetic and environmental factors. Neurexins and neuroligins play a key role in synaptogenesis and neurexin-neuroligin adhesion is one of several processes that have been implicated in autism spectrum disorders. RESULTS: In this report we describe the manual annotation of a selection of gene products known to be associated with autism and/or the neurexin-neuroligin-SHANK complex and demonstrate how a focused annotation approach leads to the creation of more descriptive Gene Ontology (GO) terms, as well as an increase in both the number of gene product annotations and their granularity, thus improving the data available in the GO database. CONCLUSIONS: The manual annotations we describe will impact on the functional analysis of a variety of future autism-relevant datasets. Comprehensive gene annotation is an essential aspect of genomic and proteomic studies, as the quality of gene annotations incorporated into statistical analysis tools affects the effective interpretation of data obtained through genome wide association studies, next generation sequencing, proteomic and transcriptomic datasets.
Subject(s)
Autistic Disorder/metabolism , Cell Adhesion Molecules, Neuronal/metabolism , Cell Physiological Phenomena , Gene Ontology , High-Throughput Nucleotide Sequencing/methods , Nerve Tissue Proteins/metabolism , Animals , Autistic Disorder/genetics , Autistic Disorder/psychology , Calcium-Binding Proteins , Cell Adhesion Molecules, Neuronal/genetics , Genome , Genomics/methods , Humans , Membrane Potentials/physiology , Mice , Models, Molecular , Nerve Tissue Proteins/genetics , Neural Cell Adhesion Molecules , Phenotype , Rats , Social Behavior , Synapses/physiology , Synaptic PotentialsABSTRACT
BACKGROUND: Parkinson's disease (PD) is a chronic progressive neurodegenerative disorder that is clinically defined in terms of motor symptoms. These are preceded by prodromal non-motor manifestations that prove the systemic nature of the disease. Identifying genes and pathways altered in living patients provide new information on the diagnosis and pathogenesis of sporadic PD. METHODS: Changes in gene expression in the blood of 40 sporadic PD patients and 20 healthy controls ("Discovery set") were analyzed by taking advantage of the Affymetrix platform. Patients were at the onset of motor symptoms and before initiating any pharmacological treatment. Data analysis was performed by applying Ranking-Principal Component Analysis, PUMA and Significance Analysis of Microarrays. Functional annotations were assigned using GO, DAVID, GSEA to unveil significant enriched biological processes in the differentially expressed genes. The expressions of selected genes were validated using RT-qPCR and samples from an independent cohort of 12 patients and controls ("Validation set"). RESULTS: Gene expression profiling of blood samples discriminates PD patients from healthy controls and identifies differentially expressed genes in blood. The majority of these are also present in dopaminergic neurons of the Substantia Nigra, the key site of neurodegeneration. Together with neuronal apoptosis, lymphocyte activation and mitochondrial dysfunction, already found in previous analysis of PD blood and post-mortem brains, we unveiled transcriptome changes enriched in biological terms related to epigenetic modifications including chromatin remodeling and methylation. Candidate transcripts as CBX5, TCF3, MAN1C1 and DOCK10 were validated by RT-qPCR. CONCLUSIONS: Our data support the use of blood transcriptomics to study neurodegenerative diseases. It identifies changes in crucial components of chromatin remodeling and methylation machineries as early events in sporadic PD suggesting epigenetics as target for therapeutic intervention.
Subject(s)
Parkinson Disease/genetics , Transcriptome/genetics , Aged , Chromobox Protein Homolog 5 , Female , Gene Expression Profiling , Humans , Male , Middle Aged , Real-Time Polymerase Chain ReactionABSTRACT
BACKGROUND: The mesencephalic dopaminergic (mDA) cell system is composed of two major groups of projecting cells in the Substantia Nigra (SN) (A9 neurons) and the Ventral Tegmental Area (VTA) (A10 cells). Selective degeneration of A9 neurons occurs in Parkinson's disease (PD) while abnormal function of A10 cells has been linked to schizophrenia, attention deficit and addiction. The molecular basis that underlies selective vulnerability of A9 and A10 neurons is presently unknown. RESULTS: By taking advantage of transgenic labeling, laser capture microdissection coupled to nano Cap-Analysis of Gene Expression (nanoCAGE) technology on isolated A9 and A10 cells, we found that a subset of Olfactory Receptors (OR)s is expressed in mDA neurons. Gene expression analysis was integrated with the FANTOM5 Helicos CAGE sequencing datasets, showing the presence of these ORs in selected tissues and brain areas outside of the olfactory epithelium. OR expression in the mesencephalon was validated by RT-PCR and in situ hybridization. By screening 16 potential ligands on 5 mDA ORs recombinantly expressed in an heterologous in vitro system, we identified carvone enantiomers as agonists at Olfr287 and able to evoke an intracellular Ca2+ increase in solitary mDA neurons. ORs were found expressed in human SN and down-regulated in PD post mortem brains. CONCLUSIONS: Our study indicates that mDA neurons express ORs and respond to odor-like molecules providing new opportunities for pharmacological intervention in disease.
Subject(s)
Dopaminergic Neurons/metabolism , Gene Expression Regulation , Mesencephalon/cytology , Mesencephalon/metabolism , Odorants , Receptors, Odorant/genetics , Animals , Cell Line , Cluster Analysis , Dopaminergic Neurons/drug effects , Female , Gene Expression Profiling , Gene Expression Regulation/drug effects , Humans , Mice , Organ Specificity/genetics , Parkinson Disease/genetics , Parkinson Disease/metabolism , Receptors, Odorant/metabolism , Recombinant Proteins , Substantia Nigra/metabolism , Transcription, GeneticABSTRACT
BACKGROUND: The Gene Ontology (GO) facilitates the description of the action of gene products in a biological context. Many GO terms refer to chemical entities that participate in biological processes. To facilitate accurate and consistent systems-wide biological representation, it is necessary to integrate the chemical view of these entities with the biological view of GO functions and processes. We describe a collaborative effort between the GO and the Chemical Entities of Biological Interest (ChEBI) ontology developers to ensure that the representation of chemicals in the GO is both internally consistent and in alignment with the chemical expertise captured in ChEBI. RESULTS: We have examined and integrated the ChEBI structural hierarchy into the GO resource through computationally-assisted manual curation of both GO and ChEBI. Our work has resulted in the creation of computable definitions of GO terms that contain fully defined semantic relationships to corresponding chemical terms in ChEBI. CONCLUSIONS: The set of logical definitions using both the GO and ChEBI has already been used to automate aspects of GO development and has the potential to allow the integration of data across the domains of biology and chemistry. These logical definitions are available as an extended version of the ontology from http://purl.obolibrary.org/obo/go/extensions/go-plus.owl.
Subject(s)
Biology , Chemistry , Genes , Vocabulary, ControlledABSTRACT
The mesencephalic dopaminergic (mDA) cell system is composed of two major groups of projecting cells in the substantia nigra (SN) (A9 neurons) and the ventral tegmental area (VTA) (A10 cells). A9 neurons form the nigrostriatal pathway and are involved in regulating voluntary movements and postural reflexes. Their selective degeneration leads to Parkinson's disease. Here, we report that gene expression analysis of A9 dopaminergic neurons (DA) identifies transcripts for alpha- and beta-chains of hemoglobin (Hb). Globin immunoreactivity decorates the majority of A9 DA, a subpopulation of cortical and hippocampal astrocytes and mature oligodendrocytes. This pattern of expression was confirmed in different mouse strains and in rat and human. We show that Hb is expressed in the SN of human postmortem brain. By microarray analysis of dopaminergic cell lines overexpressing alpha- and beta-globin chains, changes in genes involved in O(2) homeostasis and oxidative phopshorylation were observed, linking Hb expression to mitochondrial function. Our data suggest that the most famed oxygen-carrying globin is not exclusively restricted to the blood, but it may play a role in the normal physiology of the brain and neurodegenerative diseases.
Subject(s)
Neuroglia/metabolism , Neurons/metabolism , Substantia Nigra/cytology , Ventral Tegmental Area/cytology , alpha-Globins/metabolism , beta-Globins/metabolism , Animals , Flow Cytometry , Green Fluorescent Proteins , Humans , Mice , Oligonucleotide Array Sequence Analysis , RatsABSTRACT
Ontologies have emerged to become critical to support data and knowledge representation, standardization, integration, and analysis. The SARS-CoV-2 pandemic led to the rapid proliferation of COVID-19 data, as well as the development of many COVID-19 ontologies. In the interest of supporting data interoperability, we initiated a community-based effort to harmonize COVID-19 ontologies. Our effort involves the collaborative discussion among developers of seven COVID-19 related ontologies, and the merging of four ontologies. This effort demonstrates the feasibility of harmonizing these ontologies in an interoperable framework to support integrative representation and analysis of COVID-19 related data and knowledge.
ABSTRACT
BACKGROUND: The current COVID-19 pandemic and the previous SARS/MERS outbreaks of 2003 and 2012 have resulted in a series of major global public health crises. We argue that in the interest of developing effective and safe vaccines and drugs and to better understand coronaviruses and associated disease mechenisms it is necessary to integrate the large and exponentially growing body of heterogeneous coronavirus data. Ontologies play an important role in standard-based knowledge and data representation, integration, sharing, and analysis. Accordingly, we initiated the development of the community-based Coronavirus Infectious Disease Ontology (CIDO) in early 2020. RESULTS: As an Open Biomedical Ontology (OBO) library ontology, CIDO is open source and interoperable with other existing OBO ontologies. CIDO is aligned with the Basic Formal Ontology and Viral Infectious Disease Ontology. CIDO has imported terms from over 30 OBO ontologies. For example, CIDO imports all SARS-CoV-2 protein terms from the Protein Ontology, COVID-19-related phenotype terms from the Human Phenotype Ontology, and over 100 COVID-19 terms for vaccines (both authorized and in clinical trial) from the Vaccine Ontology. CIDO systematically represents variants of SARS-CoV-2 viruses and over 300 amino acid substitutions therein, along with over 300 diagnostic kits and methods. CIDO also describes hundreds of host-coronavirus protein-protein interactions (PPIs) and the drugs that target proteins in these PPIs. CIDO has been used to model COVID-19 related phenomena in areas such as epidemiology. The scope of CIDO was evaluated by visual analysis supported by a summarization network method. CIDO has been used in various applications such as term standardization, inference, natural language processing (NLP) and clinical data integration. We have applied the amino acid variant knowledge present in CIDO to analyze differences between SARS-CoV-2 Delta and Omicron variants. CIDO's integrative host-coronavirus PPIs and drug-target knowledge has also been used to support drug repurposing for COVID-19 treatment. CONCLUSION: CIDO represents entities and relations in the domain of coronavirus diseases with a special focus on COVID-19. It supports shared knowledge representation, data and metadata standardization and integration, and has been used in a range of applications.
Subject(s)
COVID-19 , Communicable Diseases , Coronavirus , Vaccines , Humans , SARS-CoV-2 , Pandemics , Amino Acids , COVID-19 Drug TreatmentABSTRACT
The conversion of the cellular prion protein (PrP(C)) to an abnormal and protease-resistant isoform is the key event in prion diseases. Mice lacking PrP(C) are resistant to prion infection, and downregulation of PrP(C) during prion infection prevents neuronal loss and the progression to clinical disease. These results are suggestive of the potential beneficial effect of silencing PrP(C) during prion diseases. However, the silencing of a protein that is widely expressed throughout the central nervous system could be detrimental to brain homeostasis. The physiological role of PrP(C) remains still unclear, but several putative functions (e.g., neuronal development and maintenance) have been proposed. To assess the influence of PrP(C) on gene expression profile in the mouse brain, we undertook a microarray analysis by using RNA isolated from the hippocampus at two different developmental stages: newborn (4.5-day-old) and adult (3-mo-old) mice, both from wild-type and Prnp(0/0) animals. Comparing the different datasets allowed us to identify "commonly" co-regulated genes and "uniquely" deregulated genes during postnatal development. The absence of PrP(C) affected several biological pathways, the most representative being cell signaling, cell-cell communication and transduction processes, calcium homeostasis, nervous system development, synaptic transmission, and cell adhesion. However, there was only a moderate alteration of the gene expression profile in our animal models. PrP(C) deficiency did not lead to a dramatic alteration of gene expression profile and produced moderately altered gene expression levels from young to adult animals. Thus, our results may provide additional support to silencing endogenous PrP(C) levels as therapeutic approach to prion diseases.
Subject(s)
Gene Expression Profiling , Gene Expression Regulation/genetics , Gene Silencing , Genetic Therapy/methods , Hippocampus/metabolism , Prion Diseases/therapy , Prions/metabolism , Age Factors , Animals , Blotting, Western , Mice , Microarray Analysis , Prion Diseases/genetics , Prion Proteins , Prions/genetics , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
Mutations in PARK7/DJ-1 are associated with autosomal recessive, early onset Parkinson disease (PD). DJ-1 is an atypical peroxiredoxin-like peroxidase that may act as a redox-dependent chaperone and a regulator of transcription. Here we show that DJ-1 plays an essential role in the expression of rearranged during transfection (RET), a receptor for the glial cell line-derived neurotrophic factor, a neuroprotective molecule for dopaminergic neurons, the main target of degeneration in PD. The inducible loss of DJ-1 triggers the establishment of hypoxia and the production of reactive oxygen species that stabilize the hypoxia-inducible factor-1alpha (HIF-1a). HIF-1a expression is required for RET down-regulation. This study establishes for the first time a molecular link between the lack of functional DJ-1 and the glial cell line-derived neurotrophic factor signaling pathway that may explain the adult-onset loss of dopaminergic neurons. Furthermore, it suggests that hypoxia may play an important role in PD.
Subject(s)
Gene Expression Regulation, Neoplastic , Intracellular Signaling Peptides and Proteins/physiology , Mutation , Neuroblastoma/metabolism , Oncogene Proteins/physiology , Proto-Oncogene Proteins c-ret/metabolism , Cell Line, Tumor , Flow Cytometry , Humans , Hypoxia , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Neuroglia/cytology , Oligonucleotide Array Sequence Analysis , Oncogene Proteins/metabolism , Oxidation-Reduction , Protein Deglycase DJ-1 , Reactive Oxygen Species , Signal TransductionABSTRACT
Dysregulation of glutamate handling ensuing downregulation of expression and activity levels of the astroglial glutamate transporter EAAT2 is implicated in excitotoxic degeneration of motor neurons in amyotrophic lateral sclerosis (ALS). We previously reported that EAAT2 (a.k.a. GLT-1) is cleaved by caspase-3 at its cytosolic carboxy-terminus domain. This cleavage results in impaired glutamate transport activity and generates a proteolytic fragment (CTE) that we found to be post-translationally conjugated by SUMO1. We show here that this sumoylated CTE fragment accumulates in the nucleus of spinal cord astrocytes of the SOD1-G93A mouse model of ALS at symptomatic stages of disease. Astrocytic expression of CTE, artificially tagged with SUMO1 (CTE-SUMO1) to mimic the native sumoylated fragment, recapitulates the nuclear accumulation pattern of the endogenous EAAT2-derived proteolytic fragment. Moreover, in a co-culture binary system, expression of CTE-SUMO1 in spinal cord astrocytes initiates extrinsic toxicity by inducing caspase-3 activation in motor neuron-derived NSC-34 cells or axonal growth impairment in primary motor neurons. Interestingly, prolonged nuclear accumulation of CTE-SUMO1 is intrinsically toxic to spinal cord astrocytes, although this gliotoxic effect of CTE-SUMO1 occurs later than the indirect, noncell autonomous toxic effect on motor neurons. As more evidence on the implication of SUMO substrates in neurodegenerative diseases emerges, our observations strongly suggest that the nuclear accumulation in spinal cord astrocytes of a sumoylated proteolytic fragment of the astroglial glutamate transporter EAAT2 could participate to the pathogenesis of ALS and suggest a novel, unconventional role for EAAT2 in motor neuron degeneration.
Subject(s)
Excitatory Amino Acid Transporter 2/toxicity , Motor Neurons/drug effects , SUMO-1 Protein/metabolism , Amyotrophic Lateral Sclerosis/genetics , Amyotrophic Lateral Sclerosis/metabolism , Animals , Astrocytes/metabolism , Axons/physiology , Axons/ultrastructure , Caspase 3/metabolism , Cell Nucleus/metabolism , Cell Nucleus/pathology , Cells, Cultured , Coculture Techniques , Excitatory Amino Acid Transporter 2/chemistry , Fluorescent Antibody Technique , Immunohistochemistry , Mice , Mice, Transgenic , Microarray Analysis , Peptide Fragments/chemistry , Peptide Fragments/toxicity , Real-Time Polymerase Chain Reaction , Superoxide Dismutase/genetics , Superoxide Dismutase-1ABSTRACT
Entamoeba histolytica is an intestinal parasite and the causative agent of amoebiasis, which is a significant source of morbidity and mortality in developing countries. Here we present the genome of E. histolytica, which reveals a variety of metabolic adaptations shared with two other amitochondrial protist pathogens: Giardia lamblia and Trichomonas vaginalis. These adaptations include reduction or elimination of most mitochondrial metabolic pathways and the use of oxidative stress enzymes generally associated with anaerobic prokaryotes. Phylogenomic analysis identifies evidence for lateral gene transfer of bacterial genes into the E. histolytica genome, the effects of which centre on expanding aspects of E. histolytica's metabolic repertoire. The presence of these genes and the potential for novel metabolic pathways in E. histolytica may allow for the development of new chemotherapeutic agents. The genome encodes a large number of novel receptor kinases and contains expansions of a variety of gene families, including those associated with virulence. Additional genome features include an abundance of tandemly repeated transfer-RNA-containing arrays, which may have a structural function in the genome. Analysis of the genome provides new insights into the workings and genome evolution of a major human pathogen.
Subject(s)
Entamoeba histolytica/genetics , Genome, Protozoan , Parasites/genetics , Animals , Entamoeba histolytica/metabolism , Entamoeba histolytica/pathogenicity , Evolution, Molecular , Fermentation , Gene Transfer, Horizontal/genetics , Glycolysis , Oxidative Stress/genetics , Parasites/metabolism , Parasites/pathogenicity , Phylogeny , Signal Transduction , Virulence/geneticsABSTRACT
BACKGROUND: Gene Ontology (GO) is a major bioinformatic resource used for analysis of large biomedical datasets, for example from genome-wide association studies, applied universally across biological fields, including Alzheimer's disease (AD) research. OBJECTIVE: We aim to demonstrate the applicability of GO for interpretation of AD datasets to improve the understanding of the underlying molecular disease mechanisms, including the involvement of inflammatory pathways and dysregulated microRNAs (miRs). METHODS: We have undertaken a systematic full article GO annotation approach focused on microglial proteins implicated in AD and the miRs regulating their expression. PANTHER was used for enrichment analysis of previously published AD data. Cytoscape was used for visualizing and analyzing miR-target interactions captured from published experimental evidence. RESULTS: We contributed 3,084 new annotations for 494 entities, i.e., on average six new annotations per entity. This included a total of 1,352 annotations for 40 prioritized microglial proteins implicated in AD and 66 miRs regulating their expression, yielding an average of twelve annotations per prioritized entity. The updated GO resource was then used to re-analyze previously published data. The re-analysis showed novel processes associated with AD-related genes, not identified in the original study, such as 'gliogenesis', 'regulation of neuron projection development', or 'response to cytokine', demonstrating enhanced applicability of GO for neuroscience research. CONCLUSIONS: This study highlights ongoing development of the neurobiological aspects of GO and demonstrates the value of biocuration activities in the area, thus helping to delineate the molecular bases of AD to aid the development of diagnostic tools and treatments.
Subject(s)
Alzheimer Disease/genetics , Encephalitis/genetics , Gene Expression , Gene Ontology , Computational Biology/methods , Humans , Microglia/metabolism , Molecular Sequence Annotation/methodsABSTRACT
BACKGROUND: The deposition of unconjugated bilirubin (UCB) in selected regions of the brain results in irreversible neuronal damage, or Bilirubin Encephalopathy (BE). Although UCB impairs a large number of cellular functions in other tissues, the basic mechanisms of neurotoxicity have not yet been fully clarified. While cells can accumulate UCB by passive diffusion, cell protection may involve multiple mechanisms including the extrusion of the pigment as well as pro-survival homeostatic responses that are still unknown. RESULTS: Transcriptome changes induced by UCB exposure in SH-SY5Y neuroblastoma cell line were examined by high density oligonucleotide microarrays. Two-hundred and thirty genes were induced after 24 hours. A Gene Ontology (GO) analysis showed that at least 50 genes were directly involved in the endoplasmic reticulum (ER) stress response. Validation of selected ER stress genes is shown by quantitative RT-PCR. Analysis of XBP1 splicing and DDIT3/CHOP subcellular localization is presented. CONCLUSION: These results show for the first time that UCB exposure induces ER stress response as major intracellular homeostasis in surviving neuroblastoma cells in vitro.
Subject(s)
Bilirubin/pharmacology , Gene Expression Profiling , Neuroblastoma/pathology , Amino Acids/metabolism , Autophagy/drug effects , Autophagy/genetics , Bilirubin/chemistry , Cell Line, Tumor , Cell Survival/drug effects , DNA-Binding Proteins/metabolism , Endoplasmic Reticulum/drug effects , Endoplasmic Reticulum/genetics , Endoplasmic Reticulum/metabolism , Homeostasis/drug effects , Humans , Neurons/drug effects , Neurons/metabolism , Neurons/pathology , Oligonucleotide Array Sequence Analysis , Protein Biosynthesis/drug effects , Protein Biosynthesis/genetics , Protein Splicing/drug effects , Protein Transport/drug effects , Protein Transport/genetics , Regulatory Factor X Transcription Factors , Reproducibility of Results , Reverse Transcriptase Polymerase Chain Reaction , Transcription Factor CHOP/metabolism , Transcription Factors/metabolism , Transcription, Genetic/drug effects , Unfolded Protein Response/drug effects , X-Box Binding Protein 1ABSTRACT
BACKGROUND: Diamond-Blackfan anaemia (DBA) is a rare inherited red cell hypoplasia characterised by a defect in the maturation of erythroid progenitors and in some cases associated with malformations. Patients have an increased risk of solid tumors. Mutations have been found in several ribosomal protein (RP) genes, i.e RPS19, RPS24, RPS17, RPL5, RPL11, RPL35A. Studies in haematopoietic progenitors from patients show that haplo-insufficiency of an RP impairs rRNA processing and ribosome biogenesis. DBA lymphocytes show reduced protein synthesis and fibroblasts display abnormal rRNA processing and impaired proliferation. RESULTS: To evaluate the involvement of non-haematopoietic tissues in DBA, we have analysed global gene expression in fibroblasts from DBA patients compared to healthy controls. Microarray expression profiling using Affymetrix GeneChip Human Genome U133A 2.0 Arrays revealed that 421 genes are differentially expressed in DBA patient fibroblasts. These genes include a large cluster of ribosomal proteins and factors involved in protein synthesis and amino acid metabolism, as well as genes associated to cell death, cancer and tissue development. CONCLUSION: This analysis reports for the first time an abnormal gene expression profile in a non-haematopoietic cell type in DBA. These data support the hypothesis that DBA may be due to a defect in general or specific protein synthesis.
Subject(s)
Anemia, Diamond-Blackfan/genetics , Fibroblasts/metabolism , Gene Expression Profiling , Ribosomal Proteins/genetics , Base Sequence , Case-Control Studies , DNA Mutational Analysis , Female , Humans , Male , Molecular Sequence Data , Mutation , Oligonucleotide Array Sequence Analysis , Protein Biosynthesis , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
Autophagy is a fundamental cellular process that is well conserved among eukaryotes. It is one of the strategies that cells use to catabolize substances in a controlled way. Autophagy is used for recycling cellular components, responding to cellular stresses and ridding cells of foreign material. Perturbations in autophagy have been implicated in a number of pathological conditions such as neurodegeneration, cardiac disease and cancer. The growing knowledge about autophagic mechanisms needs to be collected in a computable and shareable format to allow its use in data representation and interpretation. The Gene Ontology (GO) is a freely available resource that describes how and where gene products function in biological systems. It consists of 3 interrelated structured vocabularies that outline what gene products do at the biochemical level, where they act in a cell and the overall biological objectives to which their actions contribute. It also consists of 'annotations' that associate gene products with the terms. Here we describe how we represent autophagy in GO, how we create and define terms relevant to autophagy researchers and how we interrelate those terms to generate a coherent view of the process, therefore allowing an interoperable description of its biological aspects. We also describe how annotation of gene products with GO terms improves data analysis and interpretation, hence bringing a significant benefit to this field of study.
Subject(s)
Autophagy/genetics , Databases, Genetic , Gene Ontology , Parkinson Disease/genetics , Animals , Humans , Molecular Sequence Annotation , Proteins/metabolismABSTRACT
The analysis and interpretation of high-throughput datasets relies on access to high-quality bioinformatics resources, as well as processing pipelines and analysis tools. Gene Ontology (GO, geneontology.org) is a major resource for gene enrichment analysis. The aim of this project, funded by the Alzheimer's Research United Kingdom (ARUK) foundation and led by the University College London (UCL) biocuration team, was to enhance the GO resource by developing new neurological GO terms, and use GO terms to annotate gene products associated with dementia. Specifically, proteins and protein complexes relevant to processes involving amyloid-beta and tau have been annotated and the resulting annotations are denoted in GO databases as 'ARUK-UCL'. Biological knowledge presented in the scientific literature was captured through the association of GO terms with dementia-relevant protein records; GO itself was revised, and new GO terms were added. This literature biocuration increased the number of Alzheimer's-relevant gene products that were being associated with neurological GO terms, such as 'amyloid-beta clearance' or 'learning or memory', as well as neuronal structures and their compartments. Of the total 2055 annotations that we contributed for the prioritised gene products, 526 have associated proteins and complexes with neurological GO terms. To ensure that these descriptive annotations could be provided for Alzheimer's-relevant gene products, over 70 new GO terms were created. Here, we describe how the improvements in ontology development and biocuration resulting from this initiative can benefit the scientific community and enhance the interpretation of dementia data.