Autophagy Genes of Host Responds to Disruption of Gut Microbial Community by Antibiotics.

backgroundDefective autophagic machinery, such as that in Crohn's disease patients homozygous for ATG16L1 risk allele, is associated with alteration of resident gut bacterial communities. However, whether or not host autophagy responds to changes in the resident gut microbial community is not known. Here, we investigated the effect of antibiotic-induced disruption of the gut microbiome (dysbiosis) on autophagy gene expression and the expression of antimicrobial peptides/protein (AMP) over time.

aimTo test the hypothesis that antibiotic treatment may cause time-dependent changes in gut bacterial density, autophagy genes, and antimicrobial protein/peptide gene expression.

methodsMice (n = 8 per group) were treated with antibiotic cocktail and sacrificed at different intervals of recovery (days 3, 7, 10, 14, 21, 28, 35, and 42) post-antibiotics. DNA and RNA were extracted from small intestinal tissues. Bacterial density, expression of host autophagy genes, and AMP genes were analyzed by relative quantitative PCR. Fold change difference in comparison with untreated control group was calculated using 2

resultsGut bacterial density changed in a time-dependent fashion in response to antibiotic treatment. These changes were concurrent with upregulation of autophagy genes and antimicrobial peptide/protein gene expression. We further showed that an oral gavage of a resident microbe Desulfovibrio, which bloomed in antibiotic-treated animals, induced Atg5 and lysozyme (Lyz) gene expression.

conclusionAutophagy genes respond to dysbiosis induced by antibiotics. This response may be a host mechanism to detect and possibly correct dysbiosis by activating antimicrobial peptides/proteins that control the microbial load in the gut.