Project description:Kilian2024 - Immune cell dynamics in Cue-Induced Extended Human Colitis Model
Single-cell technologies such as scRNA-seq and flow cytometry provide critical insights into immune cell behavior in inflammatory bowel disease (IBD). However, integrating these datasets into computational models for dynamic analysis remains challenging. Here, Kilian et al., (2024) developed a deterministic ODE-based model that incorporates these technologies to study immune cell population changes in murine colitis. The model parameters were optimized to fit experimental data, ensuring an accurate representation of immune cell behavior over time. It was then validated by comparing simulations with experimental data using Pearson’s correlation and further tested on independent datasets to confirm its robustness. Additionally, the model was applied to clinical bulk RNA-seq data from human IBD patients, providing valuable insights into immune system dynamics and potential therapeutic strategies.
Figure 4c, obtained from the simulation of human colitis model is highlighted here.
This model is described in the article:
Kilian, C., Ulrich, H., Zouboulis, V.A. et al. Longitudinal single-cell data informs deterministic modelling of inflammatory bowel disease. npj Syst Biol Appl 10, 69 (2024). https://doi.org/10.1038/s41540-024-00395-9
Abstract:
Single-cell-based methods such as flow cytometry or single-cell mRNA sequencing (scRNA-seq) allow deep molecular and cellular profiling of immunological processes. Despite their high throughput, however, these measurements represent only a snapshot in time. Here, we explore how longitudinal single-cell-based datasets can be used for deterministic ordinary differential equation (ODE)-based modelling to mechanistically describe immune dynamics. We derived longitudinal changes in cell numbers of colonic cell types during inflammatory bowel disease (IBD) from flow cytometry and scRNA-seq data of murine colitis using ODE-based models. Our mathematical model generalised well across different protocols and experimental techniques, and we hypothesised that the estimated model parameters reflect biological processes. We validated this prediction of cellular turnover rates with KI-67 staining and with gene expression information from the scRNA-seq data not used for model fitting. Finally, we tested the translational relevance of the mathematical model by deconvolution of longitudinal bulk mRNA-sequencing data from a cohort of human IBD patients treated with olamkicept. We found that neutrophil depletion may contribute to IBD patients entering remission. The predictive power of IBD deterministic modelling highlights its potential to advance our understanding of immune dynamics in health and disease.
This model was curated during the Hackathon hosted by BioMed X GmbH in 2024.
Project description:Long intergenic noncoding RNAs (lincRNAs) are key regulators of chromatin state, yet the nature and sites of RNA-chromatin interaction are mostly unknown. Here we introduce Chromatin Isolation by RNA Purification (ChIRP), where tiling oligonucleotides retrieve specific lincRNAs and bound protein and DNA sequences, which are enumerated by deep sequencing. ChIRP-seq of two lincRNAs reveal that RNA binding sites in the genome are focal, sequence-specific, and numerous. Human telomerase RNA TERC occupies telomeres and Wnt pathway genes. HOTAIR lincRNA preferentially binds a GA-rich homopurine DNA motif to nucleate broad domains of Polycomb occupancy and histone H3 lysine 27 trimethylation. HOTAIR occupancy occurs independently of EZH2, defining the order of RNA guidance of Polycomb occupancy. ChIRP-seq is readily applicable to numerous RNAs in different cell types and biological states, thus enabling the study of RNA regulation of chromatin and gene expression at a genomic scale. Examination of 3 lincRNAs in 5 cell types
Project description:Estrogen receptor α (ERα) is the major driving transcription factor in normal mammary gland development as well as breast cancer initiation and progression.However,the fundamental mechanisms,including global cistromic and genomic transcriptional responses that are required to elicit mammary epithelial cell proliferation in response to ERα, have not been elucidated. We used chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) to identify estrogen regulated genes that directly recruit ERα in the WT mouse mammary gland
Project description:Osteoarthritis, a serious joint disease for which we currently have no disease-stratifying or modifying therapy, causes pain and functional disability for almost a quarter of a billion people world-wide. In this study chondrocytes, synoviocytes and peripheral blood from 100 patients with osteoarthritis to construct a deep molecular quantitative trait locus (molQTL) map of the disease for transcriptomics and proteomics.
Project description:Sequence-based deep learning models have become the state of the art for the analysis of the genomic regulatory code. Particularly for transcriptional enhancers, deep learning models excel at deciphering sequence features and grammar that underlie their spatiotemporal activity. To enable end-to-end enhancer modeling and design, we developed a software and modeling package, called CREsted. It combines preprocessing starting from single-cell ATAC-seq data; modeling with a choice of several architectures for training classification and regression models on either topics or pseudobulk peak heights; sequence design using multiple strategies; and downstream analysis through a collection of tools to locate transcription factor (TF) binding sites, infer the effect of a TF (activating or repressing) on enhancer accessibility, decipher enhancer grammar, and score gene loci. We demonstrate CREsted using a mouse cortex model that we validate using the BICCN collection of in vivo validated mouse brain enhancers. Classical enhancers in immune cells, including the IFN-β enhanceosome are revisited using a PBMC model, and we assess the accuracy of TF binding site predictions with ChIP-seq. Additionally, we use CREsted to compare mesenchymal-like cancer cell states between tumor types; and we investigate different fine-tuning strategies of Borzoi within CREsted, comparing their performance and explainability with CREsted models trained from scratch. Finally, we train a CREsted model on a scATAC-seq atlas of zebrafish development, and use this to design and in vivo validate cell type-specific synthetic enhancers in 3 tissues. For varying datasets we demonstrate that CREsted facilitates efficient training and analyses, enabling scrutinization of the enhancer logic and design of synthetic enhancers across tissues and species. CREsted is available at https://crested.readthedocs.io.
Project description:Long intergenic noncoding RNAs (lincRNAs) are key regulators of chromatin state, yet the nature and sites of RNA-chromatin interaction are mostly unknown. Here we introduce Chromatin Isolation by RNA Purification (ChIRP), where tiling oligonucleotides retrieve specific lincRNAs and bound protein and DNA sequences, which are enumerated by deep sequencing. ChIRP-seq of two lincRNAs reveal that RNA binding sites in the genome are focal, sequence-specific, and numerous. Human telomerase RNA TERC occupies telomeres and Wnt pathway genes. HOTAIR lincRNA preferentially binds a GA-rich homopurine DNA motif to nucleate broad domains of Polycomb occupancy and histone H3 lysine 27 trimethylation. HOTAIR occupancy occurs independently of EZH2, defining the order of RNA guidance of Polycomb occupancy. ChIRP-seq is readily applicable to numerous RNAs in different cell types and biological states, thus enabling the study of RNA regulation of chromatin and gene expression at a genomic scale.
Project description:Determining the genomic localization of chromatin features is an essential aspect of investigating gene expression control, and ChIP-Seq has long been the gold standard technique for interrogating chromatin landscapes. Recently, the development of alternative methods, such as CUT&Tag, have provided researchers with alternative strategies that eliminate the need for chromatin purification, and allow for in situ investigation of histone modifications and chromatin bound factors. Mindful of technical differences, we set out to investigate whether distinct chromatin modifications were equally compatible with these different chromatin interrogation techniques. We found that ChIP-Seq and CUT&Tag performed similarly for modifications known to reside at gene regulatory regions, such as promoters and enhancers, but major differences were observed when we assessed enrichment over heterochromatin-associated loci. Unlike ChIP-Seq, CUT&Tag detects robust levels of H3K9me3 at a substantial number of repetitive elements, with especially high sensitivity over evolutionarily young retrotransposons. IAPEz-int elements for example, exhibited underrepresentation in mouse ChIP-Seq datasets but strong enrichment using CUT&Tag. Additionally, we identified several euchromatin-associated proteins that co-purify with repetitive loci and are similarly depleted when applying ChIP-based methods. This study reveals that our current knowledge of chromatin states across the heterochromatin portions of the mammalian genome is extensively incomplete, largely due to36 limitations of ChIP-Seq. We also demonstrate that newer in situ chromatin fragmentation-based techniques, such as CUT&Tag and CUT&RUN, are more suitable for studying chromatin modifications over repetitive elements and retrotransposons.
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Project description:To identify direct NFIB target genes in HFSCs, we performed chromatin immunoprecipitation and deep sequencing (ChIP-seq) analysis using FACS-isolated HFSCs. Two independent NFIB ChIP-seq experiments were conducted.