Associations between host gene expression, the mucosal microbiome, and clinical outcome in the pelvic pouch of patients with inflammatory bowel disease.
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Associations between host gene expression, the mucosal microbiome, and clinical outcome in the pelvic pouch of patients with inflammatory bowel disease.
Abstract
<h4>Background</h4>Pouchitis is common after ileal pouch-anal anastomosis (IPAA) surgery for ulcerative colitis (UC). Similar to inflammatory bowel disease (IBD), both host genetics and the microbiota are implicated in its pathogenesis. We use the IPAA model of IBD to associate mucosal host gene expression with mucosal microbiomes and clinical outcomes. We analyze host transcriptomic data and 16S rRNA gene sequencing data from paired biopsies from IPAA patients with UC and familial adenomatous polyposis. To achieve power for a genome-wide microbiome-transcriptome association study, we use principal component analysis for transcript and clade reduction, and identify significant co-variation between clades and transcripts.<h4>Results</h4>Host transcripts co-vary primarily with biopsy location and inflammation, while microbes co-vary primarily with antibiotic use. Transcript-microbe associations are surprisingly modest, but the most strongly microbially-associated host transcript pattern is enriched for complement cascade genes and for the interleukin-12 pathway. Activation of these host processes is inversely correlated with Sutterella, Akkermansia, Bifidobacteria, and Roseburia abundance, and positively correlated with Escherichia abundance.<h4>Conclusions</h4>This study quantifies the effects of inflammation, antibiotic use, and biopsy location upon the microbiome and host transcriptome during pouchitis. Understanding these effects is essential for basic biological insights as well as for well-designed and adequately-powered studies. Additionally, our study provides a method for profiling host-microbe interactions with appropriate statistical power using high-throughput sequencing, and suggests that cross-sectional changes in gut epithelial transcription are not a major component of the host-microbiome regulatory interface during pouchitis.
doi:10.1186/s13059-015-0637-x ↗ PMID 25887922 ↗ PMC4414286 ↗
Study facts
- Organism
- Homo sapiens
- Platform
- Illumina MiSeq v2
- Age group
- adult
- Disease groups
- —
- Anatomical sites
- —
Data availability
- Analysis code
Strengths & limitations for reuse
Strengths
- Raw reads are advertised
- Feature/OTU tables are advertised
- Taxonomic tables are advertised
- Analysis code is available
- Participant-to-sample mapping is available
- Participant counts are documented
- Sample counts are documented
Extraction evidence & provenance
Each extracted field is shown with the source excerpt and location used to resolve it.
Assay
| Field | Value | Evidence |
|---|---|---|
assay.paired_end |
True |
generating paired-end reads of 175 bp in each direction. Section |
assay.platform |
Illumina MiSeq v2 |
Sequencing was performed on the Illumina MiSeq v2 platform Section |
assay.primers_reported |
True |
Primers: 515 F [GTGCCAGCMGCCGCGGTAA] and 806R [GGACTACHVGGGTWTCTAAT]. Section |
assay.read_depth_reported |
29914 |
A mean sequence depth of 29,914 sequences/sample was obtained Section |
assay.read_length |
175 |
generating paired-end reads of 175 bp in each direction. Section |
assay.sequencing_type |
amplicon_16s |
The 16S gene dataset consists of Illumina MiSeq sequences targeting the V4 variable region. Section |
assay.target_region |
V4 |
Illumina MiSeq sequences targeting the V4 variable region. Section |
Cohort
| Field | Value | Evidence |
|---|---|---|
cohort.age_group |
adult |
The cohort consisted of 265 patients (51% women) aged between 18 and 78 years Section |
cohort.disease_activity_metadata_available |
True |
to numerically score inflammation, the severity of objective traits was graded Section |
cohort.study_design |
cross_sectional |
a large, metadata-rich, cross-sectional cohort Section |
cohort.total_participants |
205 |
we analyzed 205 IPAA patients with biopsies collected from the pouch and afferent limb Section |
cohort.treatment_exposure_documented |
True |
For this cohort, antibiotic use was reported as ‘true’ if patients had taken antibiotics in the 30 days prior to biopsy collections. Section |
cohort.treatment_response_metadata_available |
True |
Acute Pouchitis (AP) based on historical or current documentation of inflammation of the pouch resolving after a single course of antibiotics Section |
Data_Assets
| Field | Value | Evidence |
|---|---|---|
data_assets.analysis_code |
True |
Input files used for MaAsLin are available from [72]. Section |
data_assets.feature_or_otu_table |
True |
this pipeline picks OTUs using a reference-based method and constructs an OTU table Section |
data_assets.open_access |
True |
"isOpenAccess": "Y" Section |
data_assets.pipeline_or_tool_versions |
True |
a data curation pipeline implemented in QIIME 1.5.0 as pick_reference_otus.py Section |
data_assets.qc_or_negative_controls_reported |
True |
The resulting OTU tables are checked for mislabeling and contamination Section |
data_assets.raw_reads |
True |
16S sequence data for this project have been filtered to remove human sequences and are publicly available Section |
data_assets.sample_metadata |
True |
Metadata are available at [ 74 ]. Section |
data_assets.taxonomic_table |
True |
Taxonomy is assigned using the Greengenes predefined taxonomy map Section |
Specimens
| Field | Value | Evidence |
|---|---|---|
specimens.body_site |
pouch and afferent limb |
with biopsies collected from the pouch and afferent limb Section |
specimens.inflamed_status_available |
True |
the inflammation score was defined as the sum of these traits Section |
specimens.longitudinal_sampling |
False |
a large, metadata-rich, cross-sectional cohort Section |
specimens.number_of_samples |
255 |
from a total of 255 samples representing 204 individuals Section |
specimens.participant_to_sample_mapping_available |
True |
255 samples representing 204 individuals; these comprised 196 PPI samples and 59 pouch samples. Section |
specimens.sample_type |
mucosal_biopsy |
Tissue biopsies were obtained from the mid-portion of the pouch and the PPI during pouchoscopy. Section |