Mapping the Human Colon Using Single Cell Sequencing

Study Overview
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Brief Summary
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The overall purpose of this study is to describe the cellular composition of the human colon and its gene expression using scRNAseq and scATACseq methods. This will potentially provide is with a detailed map of the colon aiding our understanding of how diseases of the colon develop as well as the colons influence on systemic diseases such as type II diabetes.

Detailed Description
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The human colon is composed of four distinct histological layers: Serosa, muscularis externa, submucosa, and mucosa. The inner mucosal surface is composed of columnar epithelium and glandular tissue containing crypts of Lieberkühn and secretory goblet cells, lamina propria and muscularis mucosa. Several distinct cell types have been discovered in varying degree in the colon for example enteroendocrine cells and M-cells. The cellular composition, patterns of gene expression and upstream regulatory pathways of the human colon varies across different anatomical location. This is evident in the anatomical bias in benign and malignant colorectal diseases. For example, the distal colon has a higher incidens of ulcerative colitis, diverticulitis, and chromosomal instability cancer whereas in the proximal colon ischemic colitis, collagenous colitis and microsatellite instability-induced cancer are predominant. Currently there are no studies describing baseline data for genome-wide coding, methylation or gene expression related to specific anatomic locations in the human colon. By using scRNAseq and scATACseq (Single-cell Assay of Transposase Accessible Chromatin sequencing) we will be able to map open regions in the cell's DNA and RNA, thus providing us with a unique map of the cells in the colon as well is their gene expression. ScATACseq visualizes open regions in the chromatin, generating peaks which can then be used to map DNA motifs, such as transcription factor binding sites. With the emergence of scATACseq, chromatin accessibility is in combination with gene expression data an extremely useful resource to study cell type specific regulatory DNA interactions. To further study the immunological aspects of the colon, we will extract immune cells from the colon. Lastly, full blood will be extracted to better analyze metabolic risk factors in relation to the colon's metabolic cellular regulation. The overall purpose of this study is to describe the cellular composition of the human colon and its gene expression using scRNAseq and scATACseq methods. This will potentially provide is with a detailed map of the colon aiding our understanding of how diseases of the colon develop as well as the colons influence on systemic diseases such as type II diabetes.

Official Title
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Cellular Composition of the Human Colon Using Single-cell RNA and Single-cell ATAC-sequencing.

Conditions
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Diabetes, Large Bowel Cancer, Inflammatory Bowel Diseases

Intervention / Treatment
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* Diagnostic Test: Biopsy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients referred for out-patient colonoscopy as a result of positive hemoccult. Patients able to read and understand danish. Patients able to give informed consent. Patients of Scandinavian ethnicity. Exclusion Criteria: Previous large bowel resections Suspicion pre or intraoperatively of benign or malignant disease of the colon Known inflammatory bowel disease. Immuno-modulation treatment Chemotherapy. Daily smoking > 21 weekly units of alcohol < 18 years of age

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Screening colonoscopy patients<br>Patients referred for out-patient colonoscopy in the Danish Colorectal Screening program | Diagnostic Test: Biopsy<br>* Participants included in the study, will have additional biopsies performed during their colonoscopy<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Profiling of open chromatin regions | Mapping of cell types, including rare cell types, using profiling of open chromatin regions. (ATAC-seq) in mucosal biopsies from the large bowel | 2 years | 
| Evaluation of metabolic profile | Using bioimpedance, insulin and glucose measurements and CHiP-seq we will determine patient phenotype and epigenetics to evaluate their metabolic risk-profile and correlate this to cell types in the large bowel | 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Colonic biofilm | By sequencing bacterial DNA in our samples, we will evaluate the mucosa-associated microbiome of the large bowel. This will be correlated to the two primary outcome measures | 2 years |