Using corticosteroids to reshape the gut microbiome: implications for inflammatory bowel diseases
BACKGROUND:
Commensal gut microbiota play an important role in regulating metabolic and inflammatory conditions. Reshaping intestinal microbiota through pharmacologic means may be a viable treatment option. We sought to delineate the functional characteristics of glucocorticoid-mediated alterations on gut microbiota and their subsequent repercussions on host mucin regulation and colonic inflammation.
METHODS:
Adult male C57Bl/6 mice, germ-free, Muc2-heterozygote (±), or Muc2-knockout (-/-) were injected with dexamethasone, a synthetic glucocorticoid, for 4 weeks. Fecal samples were collected for gut microbiota analysis through 16S rRNA terminal restriction fragment length polymorphism and amplicon sequencing. Intestinal mucosa was collected for mucin gene expression studies. Germ-free mice were conventionalized with gut microbes from treated and nontreated groups to determine their functional capacities in recipient hosts.
RESULTS:
Exposure to dexamethasone in wild-type mice led to substantial shifts in gut microbiota over a 4-week period. Furthermore, a significant downregulation of colonic Muc2 gene expression was observed after treatment. Muc2-knockout mice harbored a proinflammatory environment of gut microbes, characterized by the increase or decrease in prevalence of specific microbiota populations such as Clostridiales and Lactobacillaceae, respectively. This colitogenic phenotype was transmissible to IL10-knockout mice, a genetically susceptible model of colonic inflammatory disorders. Microbiota from donors pretreated with dexamethasone, however, ameliorated symptoms of inflammation.
CONCLUSIONS:
Commensal gut bacteria may be a key mediator of the anti-inflammatory effects observed in the large intestine after glucocorticoid exposure. These findings underscore the notion that intestinal microbes comprise a "microbial organ" essential for host physiology that can be targeted by therapeutic approaches to restore intestinal homeostasis.
Research Papers
- Profiling Reactive Metabolites via Chemical Trapping and Targeted Mass Spectrometry
- Does the brain listen to the gut?
- (Meta)genomic insights into the pathogenome of Cellulosimicrobium cellulans
- A robust adaptive denoising framework for real-time artifact removal in scalp EEG measurements
- Imputing Gene Expression in Uncollected Tissues Within and Beyond GTEx
- Small Rad51 and Dmc1 Complexes Often Co-occupy Both Ends of a Meiotic DNA Double Strand Break
- Controlling the Cyanobacterial Clock by Synthetically Rewiring Metabolism
- Choosing experiments to accelerate collective discovery
- The transcriptional landscape of age in human peripheral blood
- Digital signaling decouples activation probability and population heterogeneity
