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- Romagnoni, A, et al.
(författare)
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Comparative performances of machine learning methods for classifying Crohn Disease patients using genome-wide genotyping data
- 2019
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1, s. 10351-
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Tidskriftsartikel (refereegranskat)abstract
- Crohn Disease (CD) is a complex genetic disorder for which more than 140 genes have been identified using genome wide association studies (GWAS). However, the genetic architecture of the trait remains largely unknown. The recent development of machine learning (ML) approaches incited us to apply them to classify healthy and diseased people according to their genomic information. The Immunochip dataset containing 18,227 CD patients and 34,050 healthy controls enrolled and genotyped by the international Inflammatory Bowel Disease genetic consortium (IIBDGC) has been re-analyzed using a set of ML methods: penalized logistic regression (LR), gradient boosted trees (GBT) and artificial neural networks (NN). The main score used to compare the methods was the Area Under the ROC Curve (AUC) statistics. The impact of quality control (QC), imputing and coding methods on LR results showed that QC methods and imputation of missing genotypes may artificially increase the scores. At the opposite, neither the patient/control ratio nor marker preselection or coding strategies significantly affected the results. LR methods, including Lasso, Ridge and ElasticNet provided similar results with a maximum AUC of 0.80. GBT methods like XGBoost, LightGBM and CatBoost, together with dense NN with one or more hidden layers, provided similar AUC values, suggesting limited epistatic effects in the genetic architecture of the trait. ML methods detected near all the genetic variants previously identified by GWAS among the best predictors plus additional predictors with lower effects. The robustness and complementarity of the different methods are also studied. Compared to LR, non-linear models such as GBT or NN may provide robust complementary approaches to identify and classify genetic markers.
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| 4. |
- Kalla, R., et al.
(författare)
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Whole blood profiling of T-cell derived miRNA allows the development of prognostic models in inflammatory bowel disease
- 2020
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Ingår i: Journal of Crohn's & Colitis. - : Elsevier. - 1873-9946 .- 1876-4479. ; 14:12, s. 1724-1733
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: MicroRNAs (miRNAs) are cell-specific small non-coding RNAs that can regulate gene expression and have been implicated in Inflammatory Bowel Disease (IBD) pathogenesis. In our study, we define the cell-specific miRNA profiles and investigate its biomarker potential in IBD.METHODS: In a 2-stage prospective multi-centre case control study, Next Generation sequencing was performed on a discovery cohort of immunomagnetically separated leucocytes from 32 patients (9 CD, 14 UC, 8 healthy controls) and differentially expressed signals were validated in whole blood in 294 patients (97 UC, 98 CD, 98 non-IBD) using quantitative PCR. Correlations were analysed with phenotype, including need for early treatment escalation as a marker of progressive disease using Cox proportional hazards.RESULTS: In stage 1, each leucocyte subset (CD4+ and CD8+ T-cells and CD14+ monocytes) was analysed in IBD and controls. Three specific miRNAs differentiated IBD from controls in CD4+ T-cells, including miR-1307-3p (p=0.01), miR-3615 (p=0.02) and miR-4792 (p=0.01). In the extension cohort, in stage 2, miR-1307-3p was able to predict disease progression in IBD (HR 1.98, IQR:1.20-3.27;logrank p=1.80×10-3), in particular CD (HR 2.81; IQR: 1.11-3.53, p=6.50×10-4). Using blood-based multimarker miRNA models, the estimated chance of escalation in CD was 83% if 2 or more criteria were met and 90% for UC if 3 or more criteria are met.INTERPRETATION: We have identified and validated unique CD4+ T-cell miRNAs that are differentially regulated in IBD. These miRNAs may be able to predict treatment escalation and have the potential for clinical translation; further prospective evaluation is now indicated.
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| 8. |
- Kalla, R., et al.
(författare)
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Analysis of systemic epigenetic alterations in inflammatory bowel disease : defining geographical, genetic, and immune-inflammatory influences on the circulating methylome
- 2023
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Ingår i: Journal of Crohn's & Colitis. - : Oxford University Press. - 1873-9946 .- 1876-4479. ; 17:2, s. 170-184
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Epigenetic alterations may provide valuable insights into gene-environment interactions play in the pathogenesis of Inflammatory Bowel Disease (IBD).METHODS: Genome-wide methylation was measured from peripheral blood using the Illumina 450k platform in a case-control study in an inception cohort (295 controls, 154 CD, 161 UC, 28 IBD-U) with covariates of age, sex, and cell counts, deconvoluted by the Houseman method. Genotyping was performed using Illumina HumanOmniExpressExome-8 BeadChips and gene expression using Ion AmpliSeq Human Gene Expression Core Panel. Treatment escalation was characterised by the need for biological agents or surgery after initial disease remission.RESULTS: A total of 137 differentially methylated positions (DMP) were identified in IBD, including VMP1/MIR21 (p=9.11×10 -15) and RPS6KA2 (6.43×10 -13); with consistency seen across Scandinavia and UK. Dysregulated loci demonstrate strong genetic influence, notably VMP1 (p=1.53×10 -15). Age acceleration is seen in IBD (coefficient 0.94, p<2.2x10 -16). Several immuno-active genes demonstrated highly significant correlations between methylation and gene expression in IBD, in particular OSM: IBD r -0.32, p 3.64×10 -7 vs. non-IBD r -0.14, p=0.77). Multi-omic integration of methylome, genome and transcriptome also implicate specific pathways that associate with immune activation, response and regulation at disease inception. At follow up, a signature of 3 DMPs (TAP1, TESPA1, RPTOR) associated with treatment escalation to biological agents or surgery (hazard ratio of 5.19 (CI:2.14-12.56, logrank p=9.70×10 -4).CONCLUSION: These data demonstrate consistent epigenetic alterations at diagnosis in European patients with IBD, providing insights into the pathogenetic importance and translational potential of epigenetic mapping in complex disease.
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