Evolutionary and deep mining models for effective biomarker discovery

With the advent of high-throughput biology, large amounts of molecular data are available for purposeful analysis and evaluation. Extracting relevant knowledge from high-throughput biomedical datasets has become a common goal of current approaches to personalised cancer medicine and understanding cancer genotype and phenotype. However, the datasets are characterised by high dimensionality and relatively small sample sizes with small signal-to-noise ratios. Extracting and interpreting relevant knowledge from such complex datasets therefore remains a significant challenge for the fields of machine learning and data mining. This is evidenced by the limited success these methods have had in detecting robust and reliable biomarkers for cancers and other complicated diseases. This could also explain the lack of finding generic biomarkers among the identified published genes for identical diseases or clinical conditions. This thesis proposes and evaluates the efficacy of two novel feature mining models established on the basis of the evolutionary computation and deep learning paradigms to position and solve biomarker discovery as an optimisation problem. Deep learning methods lack the transparency and interpretability found in the evolutionary paradigm. To overcome the inherent issue of poor explanatory power associated with the deep learning, this research also introduces a novel deep mining model that helps to deconstruct the internal state of such deep learning models to reveal key determinants underlying its latent representations to aid feature selection. As a result, salient biomarkers for breast cancer and the positivity of the Estrogen and Progesterone receptors are discovered robustly and validated reliably across a wide range of independently generated breast cancer data samples

Non-communicable Diseases, Big Data and Artificial Intelligence

This reprint includes 15 articles in the field of non-communicable Diseases, big data, and artificial intelligence, overviewing the most recent advances in the field of AI and their application potential in 3P medicine

Developing RNA diagnostics for studying healthy human ageing

Developing strategies to cope with increase in the ageing population and age-related chronic diseases is one of the societies biggest challenges. The characteristics of the ageing process shows significant inter-individual variation. Building genomic signatures that could account for variation in health outcomes with age may facilitate early prognosis of individual age-correlated diseases (e.g. cancer, coronary artery diseases and dementia) and help in developing better targeted treatments provided years in advance of acquiring disabling symptoms for these diseases. The aim of this thesis was to explore methods for diagnosing molecular features of human ageing. In particular, we utilise multi-platform transcriptomics, independent clinical data and classification methods to evaluate which human tissues demonstrate a reproducible molecular signature for age and which clinical phenotypes correlated with these new RNA biomarkers. [Continues.

Investigating the metabolomics of treatment response in patients with inflammatory rheumatic diseases

Background: Rheumatic and musculoskeletal diseases (RMDs) are autoimmune-mediated chronic diseases affecting the joints around the body, involving an inappropriate immune response being launched against the tissues of the joint. These devastating diseases include rheumatoid arthritis (RA) and psoriatic arthritis (PsA). If insufficiently managed – or indeed in severe cases – these diseases can substantially impact a patient’s quality of life, leading to joint damage, dysfunction, and disability. However, numerous treatments exist for these diseases that control the immune-mediated factors driving disease, described as disease modifying anti-rheumatic drugs (DMARDs). Despite the success of these drugs for patients in achieving remission, they are not effective in all patients, and those who do not respond well to first-line treatments will typically be given an alternative drug on a trial-and-error basis until they respond successfully. Given the rapid and irreversible damage these diseases can induce even in the early stages, the need for early and aggressive treatment is fundamental for reaching a good outcome for the patient. Biomarkers can be employed to identify the most suitable drug to administer on a patient-to-patient basis, using these to predict who will respond to which drug. Incorporating biomarkers into the clinical management of these diseases is expected to be fundamental for precision medicine. These may come from multiple molecular sources. For example, currently used biomarkers include autoantibodies while this project primarily focuses on discovering biomarkers from the metabolome. Methodology: This project involved the secondary analyses of metabolomic and transcriptomic datasets generated from patients enrolled on multiple clinical studies. These include data from the Targeting Synovitis in Early Rheumatoid Arthritis (TaSER) (n=72), Treatment in the Rotterdam Early Arthritis Cohort (tREACH) (n=82), Characterising the Centralised Pain Phenotype in Chronic Rheumatic Disease (CENTAUR) (n=50) and Mayo Clinic - Hur et al. (2021) (n=64) – cohorts. The metabolic findings' translatability across cohorts was evaluated by incorporating datasets from various regions, including the United Kingdom, the Netherlands, and the United States of America. These multi-omic datasets were analysed using an in-house workflow developed throughout this project’s duration, involving the use of the R environment to perform exploratory data analysis, supervised machine learning and an investigation of the biological relevance of the findings. Other methods were also employed, notably an exploration and evaluation of data integration methods. Supervised machine learning was included to generate molecular profiles of treatment responses from multiple datasets. Doing so showed the value of combining multiple weakly-associated analytes in a model that could predict patient responses. However, an important component, the validation of these models, could not be performed in this work, although suggestions were made throughout of possible next steps. Results and Discussion: The analysis of the TaSER metabolomic data showed metabolites associated with methotrexate response after 3 months of treatment. Tryptophan and argininerelated metabolites were included in the metabolic model predictive of the 3-month response. While the model was not directly validated using subsequent datasets, including the tREACH and Mayo Clinic cohorts, additional features from these pathways were associated with treatment response. Included across cohorts were several tryptophan metabolites, including those derived from indole. Since these are largely produced via the gut microbiome it was suggested that the gut microbiome may influence the effectiveness of RMD treatments. Since RA and PsA were considered in this work as two archetypal RMDs, part of the project intended to investigate whether there were shared metabolic features found in association to treatment response in both diseases. These common metabolites were not clearly identified, although arginine-related metabolites were observed in models generated from the TaSER and CENTAUR cohorts in association with response to treatment in both conditions. Owing to the limitations of the untargeted metabolomic approach, this work was expected to provide an initial step in understanding the involvement of arginine and tryptophan related pathways in influencing treatment response in RMDs. Not performed in this work, it was expected that targeted metabolomics would provide clearer insights into these metabolites, providing absolute quantification with the identification of these features of interest in the patient samples. It was expected that expanding the cohort sizes and incorporating other omics platforms would provide a greater understanding of the mechanisms of the resolution of RMDs and inform future therapeutic targets. An important output from this project was the analytical pipeline developed and employed throughout for the omics analysis to inform biomarker discovery. Later work will involve generating a package in the R environment called markerHuntR. The R scripts for the functions with example datasets can be found at https://github.com/cambest202/markerHuntR.git. It is anticipated that the package will soon be described in more detail in a publication. The package will be available for researchers familiar with R to perform similar analyses as those described in this work

Computational Methods for the Analysis of Genomic Data and Biological Processes

In recent decades, new technologies have made remarkable progress in helping to understand biological systems. Rapid advances in genomic profiling techniques such as microarrays or high-performance sequencing have brought new opportunities and challenges in the fields of computational biology and bioinformatics. Such genetic sequencing techniques allow large amounts of data to be produced, whose analysis and cross-integration could provide a complete view of organisms. As a result, it is necessary to develop new techniques and algorithms that carry out an analysis of these data with reliability and efficiency. This Special Issue collected the latest advances in the field of computational methods for the analysis of gene expression data, and, in particular, the modeling of biological processes. Here we present eleven works selected to be published in this Special Issue due to their interest, quality, and originality

ENDOMET database – A means to identify novel diagnostic and prognostic tools for endometriosis

Endometriosis is a common benign hormone reliant inflammatory gynecological disease that affects fertile aged women and has a considerable economic impact on healthcare systems. Symptoms include intense menstrual pain, persistent pelvic pain, and infertility. It is defined by the existence of endometrium-like tissue developing in ectopic locations outside the uterine cavity and inflammation in the peritoneal cavity. Endometriosis presents with multifactorial etiology, and despite extensive research the etiology is still poorly understood. Diagnostic delay from the onset of the disease to when a conclusive diagnosis is reached is between 7–12 years. There is no known cure, although symptoms can be improved with hormonal medications (which often have multiple side effects and prevent pregnancy), or through surgery which carries its own risk. Current non-invasive tools for diagnosis are not sufficiently dependable, and a definite diagnosis is achieved through laparoscopy or laparotomy. This study was based on two prospective cohorts: The ENDOMET study, including 137 endometriosis patients scheduled for surgery and 62 healthy women, and PROENDO that included 138 endometriosis patients and 33 healthy women. Our long-term goal with the current study was to support the discovery of innovative new tools for efficient diagnosis of endometriosis as well as tools to further understand the etiology and pathogenesis of the disease. We set about achieving this goal by creating a database, EndometDB, based on a relational data model, implemented with PostgreSQL programming language. The database allows e.g., for the exploration of global genome-wide expression patterns in the peritoneum, endometrium, and in endometriosis lesions of endometriosis patients as well as in the peritoneum and endometrium of healthy control women of reproductive age. The data collected in the EndometDB was also used for the development and validation of a symptom and biomarker-based predictive model designed for risk evaluation and early prediction of endometriosis without invasive diagnostic methods. Using the data in the EndometDB we discovered that compared with the eutopic endometrium, the WNT- signaling pathway is one of the molecular pathways that undergo strong changes in endometriosis. We then evaluated the potential role for secreted frizzled-related protein 2 (SFRP-2, a WNT-signaling pathway modulator), in improving endometriosis lesion border detection. The SFRP-2 expression visualizes the lesion better than previously used markers and can be used to better define lesion size and that the surgical excision of the lesions is complete.ENDOMET tietokanta – Keino tunnistaa uusi diagnostinen ja ennustava työkalu endometrioosille Endometrioosi on yleinen hyvänlaatuinen, hormoneista riippuvainen tulehduksellinen lisääntymisikäisten naisten gynekologinen sairaus, joka kuormittaa terveydenhuoltojärjestelmää merkittävästi. Endometrioositaudin oireita ovat mm. voimakas kuukautiskipu, jatkuva lantion alueen kipu ja hedelmättömyys. Sairaus määritellään kohdun limakalvon kaltaisen kudoksen esiintymisenä kohdun ulkopuolella sekä siihen liittyvänä vatsakalvon tulehduksena. Endometrioosin etiologia on monitahoinen, ja laajasta tutkimuksesta huolimatta edelleen huonosti tunnettu. Kesto taudin puhkeamisesta lopullisen diagnoosin saamiseen on usein jopa 7–12 vuotta. Sairauteen ei tunneta parannuskeinoa, mutta oireita voidaan lievittää esimerkiksi hormonaalisilla lääkkeillä (joilla on usein monia sivuvaikutuksia ja jotka estävät raskauden) tai leikkauksella, johon liittyy omat tunnetut riskit. Nykyiset ei-invasiiviset diagnoosityökalut eivät ole riittävän luotettavia sairauden tunnistamiseen, ja varma endometrioosin diagnoosi saavutetaan laparoskopian tai laparotomian avulla. Tämä tutkimus perustui kahteen prospektiiviseen kohorttiin: ENDOMET-tutkimuk-seen, johon osallistui 137 endometrioosipotilasta ja 62 terveellistä naista, sekä PROENDO-tutkimukseen, johon osallistui 138 endometrioosipotilasta ja 33 terveellistä naista. Tässä tutkimuksessa pitkän aikavälin tavoitteemme oli löytää uusia työkalujen endometrioosin diagnosointiin, sekä ymmärtää endometrioosin etiologiaa ja patogeneesiä. Ensimmäisessä vaiheessa loimme EndometDB –tietokannan PostgreSQL-ohjelmointi-kielellä. Tämän osittain avoimeen käyttöön vapautetun tietokannan avulla voidaan tutkia genomin, esimerkiksi kaikkien tunnettujen geenien ilmentymistä peritoneumissa, endo-metriumissa ja endometrioosipotilaiden endometrioosileesioissa EndometDB-tietokantaan kerättyjä tietoja käytettiin oireiden ja biomarkkeripohjaisen ennustemallin kehittämiseen ja validointiin. Malli tuottaa riskinarvioinnin endometrioositaudin varhaiseen ennustamiseen ilman laparoskopiaa. Käyttäen EndometDB-tietokannan tietoja havaitsimme, että endo-metrioositautikudoksessa tapahtui voimakkaita geeni-ilmentymisen muutoksia erityisesti geeneissä, jotka liittyvät WNT-signalointireitin säätelyyn. Keskeisin löydös oli, että SFRP-2 proteiinin ilmentyminen oli huomattavasti koholla endometrioosikudoksessa ja SFRP-2 proteiinin immunohistokemiallinen värjäys erottaa endometrioosin tautikudoksen terveestä kudoksesta aiempia merkkiaineita paremmin. Löydetyllä menetelmällä voidaan siten selvittää tautikudoksen laajuus ja tarvittaessa osoittaa, että leikkauksella on kyetty poistamaan koko sairas kudos