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PreBIND and Textomy--mining the biomedical literature for protein-protein interactions using a support vector machine.

BACKGROUND: The majority of experimentally verified molecular interaction and biological pathway data are present in the unstructured text of biomedical journal articles where they are inaccessible to computational methods. The Biomolecular interaction network database (BIND) seeks to capture these data in a machine-readable format. We hypothesized that the formidable task-size of backfilling the database could be reduced by using Support Vector Machine technology to first locate interaction information in the literature. We present an information extraction system that was designed to locate protein-protein interaction data in the literature and present these data to curators and the public for review and entry into BIND. RESULTS: Cross-validation estimated the support vector machine's test-set precision, accuracy and recall for classifying abstracts describing interaction information was 92%, 90% and 92% respectively. We estimated that the system would be able to recall up to 60% of all non-high throughput interactions present in another yeast-protein interaction database. Finally, this system was applied to a real-world curation problem and its use was found to reduce the task duration by 70% thus saving 176 days. CONCLUSIONS: Machine learning methods are useful as tools to direct interaction and pathway database back-filling; however, this potential can only be realized if these techniques are coupled with human review and entry into a factual database such as BIND. The PreBIND system described here is available to the public at http://bind.ca. Current capabilities allow searching for human, mouse and yeast protein-interaction information.

Algorithms↗

New technologies for chemical genetics.

Chemical genetics, in which small molecules are used in lieu of mutations to study biological processes, requires large and diverse chemical libraries to specifically perturb different biological pathways. Here we describe a suite of technologies that enable chemical libraries prepared by split-pool solid phase synthesis to be screened in a diverse range of chemical genetic assays. Compounds are synthesized on 500 micron high-capacity polystyrene beads, and arrayed into individual wells of 384-well plates using a hand-held bead arrayer. Compounds are cleaved from synthesis beads using a chemically-resistant ceramic dispensing system, producing individual stock solutions of single compounds. Nanoliter volumes of these solutions are then transferred into assay plates using an array of stainless steel pins mounted on a robotic arm. We have designed reusable 1536- and 6144-well assay plates made of silicone rubber that can be cast in the laboratory and filled by hand. This integrated technology platform enables hundreds of biological assays to be performed from the product of a single synthesis bead, enabling the results of different chemical genetic experiments to be directly compared.

Cell Extracts↗

Endothelial cell function: biologic and physiologic functions in health and disease.

Endothelial cells (EC) form a monolayer with a strategic role in the control of many physiologic and biologic pathways. Although the endothelium initially was thought to be an inert and passive barrier of the vasculature, the diverse functions of EC have been better defined in the past decade. EC play an important role in the control of coagulation, vasomotor tone, growth of vascular smooth muscle cells, white cell trafficking, ischemic and reperfusion injuries, and the development of arteriosclerosis. Owing to their location in the arterial tree, EC also are considered a potential target for gene therapy. The introduction of foreign DNA into EC by in vitro transfection with viral vectors has produced encouraging results when using genes that encode for proteins such as insulin and urokinase. The seeding of EC onto vascular grafts appears to convey the thromboresistant properties of saphenous vein to an artificial surface. This review focuses on the important biologic and physiologic functions of EC in health and disease.

Animals↗

A new role for microRNA pathways: modulation of degeneration induced by pathogenic human disease proteins.

MicroRNAs (miRNAs) are small noncoding RNAs that regulate the expression of target transcript mRNAs. Many miRNAs have been defined, however their roles and the processes influenced by miRNA pathways are still being elucidated. A role for miRNAs in development and cancer has been described. We recently isolated the miRNA bantam (ban) in a genetic screen for modulators of pathogenicity of a human neurodegenerative disease model in Drosophila. These studies showed that upregulation of ban mitigates degeneration induced by the pathogenic polyglutamine (polyQ) protein Ataxin-3, which is mutated in the human polyglutamine disease spinocerebellar ataxia type 3 (SCA3). To address the broader role for miRNAs in neuroprotection, we also showed that loss of all miRNAs, by dicer mutation, dramatically enhances pathogenic polyQ protein toxicity in flies and in human HeLa cells. These studies suggest that miRNAs may be important for neuronal survival in the context of human neurodegenerative disease. These studies provide the foundation to define the miRNAs involved in neurodegenerative disease, and the biological pathways affected.

Animals↗

Gene prioritization through genomic data fusion.

The identification of genes involved in health and disease remains a challenge. We describe a bioinformatics approach, together with a freely accessible, interactive and flexible software termed Endeavour, to prioritize candidate genes underlying biological processes or diseases, based on their similarity to known genes involved in these phenomena. Unlike previous approaches, ours generates distinct prioritizations for multiple heterogeneous data sources, which are then integrated, or fused, into a global ranking using order statistics. In addition, it offers the flexibility of including additional data sources. Validation of our approach revealed it was able to efficiently prioritize 627 genes in disease data sets and 76 genes in biological pathway sets, identify candidates of 16 mono- or polygenic diseases, and discover regulatory genes of myeloid differentiation. Furthermore, the approach identified a novel gene involved in craniofacial development from a 2-Mb chromosomal region, deleted in some patients with DiGeorge-like birth defects. The approach described here offers an alternative integrative method for gene discovery.

Algorithms↗

A traveling salesman approach for predicting protein functions.

BACKGROUND: Protein-protein interaction information can be used to predict unknown protein functions and to help study biological pathways. RESULTS: Here we present a new approach utilizing the classic Traveling Salesman Problem to study the protein-protein interactions and to predict protein functions in budding yeast Saccharomyces cerevisiae. We apply the global optimization tool from combinatorial optimization algorithms to cluster the yeast proteins based on the global protein interaction information. We then use this clustering information to help us predict protein functions. We use our algorithm together with the direct neighbor algorithm 1 on characterized proteins and compare the prediction accuracy of the two methods. We show our algorithm can produce better predictions than the direct neighbor algorithm, which only considers the immediate neighbors of the query protein. CONCLUSION: Our method is a promising one to be used as a general tool to predict functions of uncharacterized proteins and a successful sample of using computer science knowledge and algorithms to study biological problems.

Journal Article↗

KLHL17 as a Prognostic Indicator and Therapeutic Target in Cervical Cancer: A Comprehensive Analysis.

INTRODUCTION: This study aims to clarify the role of kelch like family member 17 (KLHL17) in cervical cancer (CESC) is unclear. OBJECTIVE: To clarify this uncertainty, our research employed bioinformatics analysis coupled with experimental corroboration. METHODS: We utilized the Cancer Genome Atlas (TCGA) database to assess the expression of KLHL17 in various cancers, specifically CESC, and to explore its association with clinical characteristics, diagnostic utility, and prognostic significance in CESC. The current investigation delved into the potential regulatory pathways related to KLHL17, examining its connection with the infiltration of immune cells, the expression of immune checkpoint genes, the status of microsatellite instability (MSI), and the efficacy of diverse therapeutic agents in CESC. The research analyzed KLHL17 expression patterns using single-cell sequencing data from CESC samples and investigated the genetic variations of KLHL17 within this context. KLHL17 expression was validated using GSE145372. The presence and levels of KLHL17 in different cell lines were validated through quantitative real-time PCR (qRT-PCR) assays. RESULTS: KLHL17 exhibited irregular expression profiles across various cancer types, including CESC. Furthermore, increased KLHL17 levels in CESC patients were significantly associated with a lower progression-free survival (PFS) rate (hazard ratio: 1.62; 95% confidence interval: 1.01-2.60, p = 0.044). Moreover, KLHL17 expression emerged as a distinct prognostic indicator for CESC patients (p = 0.031). It has been associated with various biological pathways, such as cytokine-cytokine receptor interaction, primary immunodeficiency, cell adhesion molecules (CAMs), chemokine signaling pathway, steroid hormone biosynthesis, and others. The expression levels of KLHL17 were found to correlate with the presence of immune cells, the expression of immune checkpoint genes, and the status of MSI within CESC. Furthermore, KLHL17 expression exhibited a significant and inverse correlation with XMD15-27, rTRAIL, Paclitaxel, tp4ek, and tp4ek-k6. Furthermore, KLHL17 was found to be significantly positively regulated in CESC cell lines. DISCUSSION: The findings suggest that KLHL17 is involved in the progression of CESC and may serve as a potential prognostic marker and therapeutic target. KLHL17's association with immune cell infiltration and immune checkpoint genes indicates a role in immuneevasion. Future research should focus on validating these findings through independent datasets and experimental studies to elucidate the molecular mechanisms underlying KLHL17's role in CESC progression and immune regulation. CONCLUSION: KLHL17 is a promising prognostic marker and potential therapeutic target in CESC.

Humans↗

[Genetics of psychoses under a new aspect].

To analyze the biological pathways of the genetical activity in psychoses is growing more and more to an important goal. The research in this field should be started on the assumption of a multifactorial hereditary system controlling the somatic base of mental illness in a specific way as can be argued from twin and family studies. Screening the present data, there is strong evidence that the metabolism of affective psychoses is characterized by quantitative deviations only concerning the 5-hydroxytryptamine and norepinephrine turnover particularly. The biochemical findings in schizophrenic psychoses are suspicious for qualitative abnormities too. There are some indications of toxic products in the catecholamine metabolism and of antibodies against brain substances. All these disturbances could be caused by structural gene mutants or by mutations of the genetical regulatory system changing the sensitivity for the environmental stimulus. The simultaneous investigation of simple inherited serum groups is described as a useful tool for biological marking of the responsible genotypes.

Environmental Exposure↗

Inverse gene expression patterns for macrophage activating hepatotoxicants and peroxisome proliferators in rat liver.

Macrophage activation contributes to adverse effects produced by a number of hepatotoxic compounds. Transcriptional profiles elicited by two macrophage activators, LPS and zymosan A, were compared to those produced by 100 paradigm compounds (mostly hepatotoxicants) using cDNA microarrays. Several hepatotoxicants previously reported to activate liver macrophages produced transcriptional responses similar to LPS and zymosan, and these were used to construct a gene signature profile for macrophage activators in the liver. Measurement of cytokine mRNAs in the same liver samples by RT-PCR independently confirmed that these compounds are associated with macrophage activation. In addition to expected effects on acute phase proteins and metabolic pathways that are regulated by LPS and inflammation, a strong induction was observed for many endoplasmic reticulum-associated stress/chaperone proteins. Additionally, many genes in our macrophage activator signature profile were well-characterized PPARalpha-induced genes which were repressed by macrophage activators. A shared gene signature profile for peroxisome proliferators was determined using a training set of clofibrate, WY 14643, diethylhexylphthalate, diisononylphthalate, perfluorodecanoic acid, perfluoroheptanoic acid, and perfluorooctanoic acid. The signature profile included macrophage activator-induced genes that were repressed by peroxisome proliferators. NSAIDs comprised an interesting pharmacological class in that some compounds, notably diflunisal, co-clustered with peroxisome proliferators whereas several others co-clustered with macrophage activators, possibly due to endotoxin exposure secondary to their adverse effects on the gastrointestinal system. While much of these data confirmed findings from the literature, the transcriptional patterns detected using this toxicogenomics approach showed relationships between genes and biological pathways requiring complex analysis to be discerned.

Animals↗

ProteoformDB: A Built-In Application to Generate Proteoform Database.

Proteins play essential functions through their complex regulations on cell-type-specific expression, localization, and molecular complexes. Protein complexity is further enhanced by proteoforms, which are the diverse molecular forms that each gene can produce through genomic alterations, transcriptional variations, translational regulations, and protein modifications. Profiling of proteoforms is a promising method for gaining a deeper understanding of the role of proteins in biological pathways and disease mechanisms. Here, we developed ProteoformDB, an application tool for generating proteoform databases, and we cataloged a total of over one million unique single-site human proteoforms. We showed that ProteoformDB can serve as a valuable resource to document the experimentally identified proteoforms in a database, supporting protein characterization in quantitative proteomics for both total protein abundances and modified protein forms.

Humans↗

Assessing the impact of alternative splicing on domain interactions in the human proteome.

We have constructed a database of alternatively spliced protein forms (ASP), consisting of 13,384 protein isoform sequences of 4422 human genes (www.bioinformatics.ucla.edu/ASP). We identified fifty protein domain types that were selectively removed by alternative splicing at much higher frequencies than average (p-value < 0.01). These include many well-known protein-interaction domains (e.g., KRAB; ankyrin repeats; Kelch) including some that have been previously shown to be regulated functionally by alternative splicing (e.g., collagen domain). We present a number of novel examples (Kruppel transcription factors; Pbx2; Enc1) from the ASP database, illustrating how this pattern of alternative splicing changes the structure of a biological pathway, by redirecting protein interaction networks at key switch points. Our bioinformatics analysis indicates that a major impact of alternative splicing is removal of protein-protein interaction domains that mediate key linkages in protein interaction networks. ASP expands the available dataset of human alternatively spliced protein forms from 1989 human genes (SwissProt release 42) to 5413 (nonredundant set, ASP + SwissProt), a nearly 3-fold increase. ASP will enhance the existing pool of protein sequences that are searched by mass spectroscopy software during the identification of peptide fragments.

Alternative Splicing↗

MARS: microarray analysis, retrieval, and storage system.

BACKGROUND: Microarray analysis has become a widely used technique for the study of gene-expression patterns on a genomic scale. As more and more laboratories are adopting microarray technology, there is a need for powerful and easy to use microarray databases facilitating array fabrication, labeling, hybridization, and data analysis. The wealth of data generated by this high throughput approach renders adequate database and analysis tools crucial for the pursuit of insights into the transcriptomic behavior of cells. RESULTS: MARS (Microarray Analysis and Retrieval System) provides a comprehensive MIAME supportive suite for storing, retrieving, and analyzing multi color microarray data. The system comprises a laboratory information management system (LIMS), a quality control management, as well as a sophisticated user management system. MARS is fully integrated into an analytical pipeline of microarray image analysis, normalization, gene expression clustering, and mapping of gene expression data onto biological pathways. The incorporation of ontologies and the use of MAGE-ML enables an export of studies stored in MARS to public repositories and other databases accepting these documents. CONCLUSION: We have developed an integrated system tailored to serve the specific needs of microarray based research projects using a unique fusion of Web based and standalone applications connected to the latest J2EE application server technology. The presented system is freely available for academic and non-profit institutions. More information can be found at http://genome.tugraz.at.

Algorithms↗

A systematic model to predict transcriptional regulatory mechanisms based on overrepresentation of transcription factor binding profiles.

An important aspect of understanding a biological pathway is to delineate the transcriptional regulatory mechanisms of the genes involved. Two important tasks are often encountered when studying transcription regulation, i.e., (1) the identification of common transcriptional regulators of a set of coexpressed genes; (2) the identification of genes that are regulated by one or several transcription factors. In this study, a systematic and statistical approach was taken to accomplish these tasks by establishing an integrated model considering all of the promoters and characterized transcription factors (TFs) in the genome. A promoter analysis pipeline (PAP) was developed to implement this approach. PAP was tested using coregulated gene clusters collected from the literature. In most test cases, PAP identified the transcription regulators of the input genes accurately. When compared with chromatin immunoprecipitation experiment data, PAP's predictions are consistent with the experimental observations. When PAP was used to analyze one published expression-profiling data set and two novel coregulated gene sets, PAP was able to generate biologically meaningful hypotheses. Therefore, by taking a systematic approach of considering all promoters and characterized TFs in our model, we were able to make more reliable predictions about the regulation of gene expression in mammalian organisms.

Animals↗

Monoclonal antibody therapy of ovarian cancer.

Despite advances in understanding and treatment, ovarian cancer remains a major cause of cancer mortality worldwide. Debulking surgery and paclitaxel/carboplatin chemotherapy induce good initial responses in most patients, although most cases of advanced disease are not controlled. Monoclonal antibodies hold promise as a potential incremental advance for the treatment of the disease. Antibodies can be used to stimulate the immune response, target tumor-specific receptors to induce antibody-dependent cellular cytotoxicity or interfere with biologic pathways. They can also be used to deliver therapeutic radioisotopes to malignant cells. Oregovomab is in Phase III clinical trials as a consolidation treatment post front-line therapy to trigger tumor-specific cellular immunity. Bevacizumab, which blocks vascular endothelial growth factor, will be entering Phase III as an adjuvant to front-line chemotherapy with a direct effect on angiogenesis. Additional immunostimulating, immune counter-regulatory and receptor-targeting approaches are also reviewed. The family of epidermal growth factor receptors including epidermal growth factor receptor 1 (HER-1) and 2 (HER-2) are both expressed in ovarian cancer and are the subject of ongoing research and development. The recent disappointing results with 90-yttrium-labeled anti-HMFG by single intraperitoneal administration have left the radiopharmaceutical field without a Phase III candidate. Identification of novel targets may advance this therapeutic area in the future. The rapid advances in the fields of immunoregulation and tumor biology should permit an accelerated introduction of antibodies for the treatment of ovarian cancer. These antibodies could complement novel small molecules that are also in development.

Angiogenesis Inhibitors↗

Recent developments in computational proteomics.

The mapping of the human genome was completed earlier this year and efforts are underway to understand the role of gene products (i.e. proteins) in biological pathways and human disease and to exploit their functional roles to derive protein therapeutics and protein-based drugs. A key component to the next revolution in the 'post-genomic' era will be the increasingly widespread use of protein structure in rational experimental design. Improvements in quality, availability and utility of large-scale 3D and 4D protein structural information are enabling a revolution in rational design, having particular impact on drug discovery and optimization. New computational methodologies now yield modeled structures that are, in many cases, quantitatively comparable with crystal structures, at a fraction of the cost.

Animals↗

Strength of evidence linking oral conditions and systemic disease.

Associations between dental diseases and systemic outcomes are potentially important because of the high occurrence of dental diseases. If this extremely common source of chronic infection (dental disease) leads to an increased morbidity and mortality rate, the public health impact of oral disease on millions of Americans would be substantial. Recent studies demonstrate an association between dental and systemic diseases, including systemic infections, cardiovascular disease, pregnancy outcomes, respiratory diseases, and increased all-cause mortality rate. Because there are several common risk factors for oral and systemic diseases, and limitations in published studies, a careful interpretation is needed. Confounding (shared risk factors for both systemic and dental disease) may explain part of the reported associations. It is also plausible that there may be a causal link. It is likely that if there is a causal link, several pathways and mediators coexist, linking oral and systemic disease. Bacteremia, bacterial endotoxins, cytokines, and other inflammatory mediators could conceivably be playing a direct or indirect role. Missing teeth are a surrogate marker for previous dental infection, and may also lead to altered dietary intake. Hence, diet may be an additional mediator for several of these outcomes. We caution clinicians not to recommend extracting infected teeth, based on the periodontal-systemic disease associations, if the teeth do not warrant extraction otherwise, because loss of teeth and edentulousness are associated with increased risk of systemic diseases. When assessed against causal-defined criteria, the evidence suggests possible causal associations between chronic periodontal disease and tooth loss with cardiovascular disease, bacterial endocarditis, pregnancy outcomes, and all-cause overall mortality. Further studies are needed to show consistency, to corroborate that the associations are independent of common risk factors for both systemic and dental disease, including healthy lifestyle factors, and to evaluate different biological pathways.

Bacterial Infections↗

Automated detection of informative combined effects in genetic association studies of complex traits.

There is a growing body of evidence suggesting that the relationships between gene variability and common disease are more complex than initially thought and require the exploration of the whole polymorphism of candidate genes as well as several genes belonging to biological pathways. When the number of polymorphisms is relatively large and the structure of the relationships among them complex, the use of data mining tools to extract the relevant information is a necessity. Here, we propose an automated method for the detection of informative combined effects (DICE) among several polymorphisms (and nongenetic covariates) within the framework of association studies. The algorithm combines the advantages of the regressive approaches with those of data exploration tools. Importantly, DICE considers the problem of interaction between polymorphisms as an effect of interest and not as a nuisance effect. We illustrate the method with three applications on the relationship between (1). the P-selectin gene and myocardial infarction, (2). the cholesteryl ester transfer protein gene and plasma high-density-lipoprotein cholesterol concentration, and (3). genes of the renin-angiotensin-aldosterone system and myocardial infarction. The applications demonstrated that the method was able to recover results already found using other approaches, but in addition detected biologically sensible effects not previously described.

Algorithms↗

Profiling of aortic smooth muscle cell gene expression in response to chronic inhibition of nitric oxide synthase in rats.

BACKGROUND: Chronic inhibition of nitric oxide (NO) synthesis by N(omega)-nitro-L-arginine methyl ester (L-NAME) induces hypertension associated with remodeling of the arterial wall. In this study, we aimed at identifying genes and pathways involved in this process in aortic smooth muscle cells from Fischer 344 rats, which exhibit an accelerated hypertension after administration of L-NAME. METHODS AND RESULTS: We studied the transcriptional profile of aortic media after 15 days (moderate hypertension) and 30 days (accelerated hypertension) of L-NAME administration (50 mg x kg(-1) x d(-1)) by using rat Affymetrix Genechips, and we present a large-scale validation of the DNA chip results by real-time reverse transcription-polymerase chain reaction (RT-PCR). We observed, in aortic media, a progressive increase in the number of modulated genes during L-NAME administration, with 53 genes significantly modulated after 15 days and 147 genes after 30 days. These expression changes were confirmed at 87% by RT-PCR. We found 28 known genes regulated at both 15 and 30 days (96% confirmation by RT-PCR). The functional classification of the regulated genes highlights 3 major biological pathways modulated in aortic media during L-NAME administration: genes regulating cell proliferation, genes involved in the extracellular matrix remodeling, and genes of the NO/cGMP signaling pathway. CONCLUSIONS: As a consequence of the genomic approach, we observed a large increase in modulation of gene expression along the evolution of the model and the progressive implication of compensatory mechanisms, making expression profile analysis more complex.

Animals↗