Ketogenic diet alleviates colitis by reduction of colonic group 3 innate lymphoid cells through altering gut microbiome

Cheng Kong,Yongqiang Liu,Jide He,Huanlong Qin,Yanlei Ma,Xuebing Yan,Linsheng Huang,Ajay Goel,Yefei Zhu,Matthew F. Kalady,Renyuan Gao

doi:10.1038/s41392-021-00549-9

Abstract

Accumulating evidence suggests that ketogenic diets (KDs) mediate the rise of circulating ketone bodies and exert a potential anti-inflammatory effect; however, the consequences of this unique diet on colitis remain unknown. We performed a series of systematic studies using a dextran sulfate sodium (DSS) animal model of inflammatory colitis. Animals were fed with a KD, low-carbohydrate diet (LCD), or normal diet (ND). Germ-free mice were utilized in validation experiments. Colon tissues were analyzed by transcriptome sequencing, RT2 profiler PCR array, histopathology, and immunofluorescence. Serum samples were analyzed by metabolic assay kit. Fecal samples were analyzed by 16S rRNA gene sequencing, liquid chromatography–mass spectrometry and gas chromatography–mass spectrometry. We observed that KD alleviated colitis by altering the gut microbiota and metabolites in a manner distinct from LCD. Quantitative diet experiments confirmed the unique impact of KD relative to LCD with a reproducible increase in Akkermansia, whereas the opposite was observed for Escherichia/Shigella. After colitis induction, the KD protected intestinal barrier function, and reduced the production of RORγt+CD3− group 3 innate lymphoid cells (ILC3s) and related inflammatory cytokines (IL-17α, IL-18, IL-22, Ccl4). Finally, fecal microbiota transplantation into germ-free mice revealed that the KD- mediated colitis inhibition and ILC3 regulation were dependent on the modification of gut microbiota. Taken together, our study presents a global view of microbiome-metabolomics changes that occur during KD colitis treatment, and identifies the regulation of gut microbiome and ILC3s as novel targets involving in IBD dietary therapy.

Highlights

Inflammatory bowel disease (IBD) is a complicated chronic inflammatory disease that involves various genetic and environmental driving factors.[1]
The ketogenic diets (KDs) significantly reduced inflammatory responses, protected intestinal barrier function, and reduced ILC3 production and the expression of related inflammatory cytokines, whereas the opposite effects were observed for the lowcarbohydrate diet (LCD)
FMT revealed that the inhibitory effect of the KD in colitis was dependent on its modification of gut microbiota

Summary

RESULTS

KD contributes to beneficial gut microbiota and related and ND-C groups, respectively. The functional potential of compared to the ND, whereas the opposite was observed for the gut microbiota was analyzed using PICRUSt and LEfSe These findings were confirmed by quantitative PCR (Fig. 3j), Discriminant Analysis (LDA) score > 3.0, p < 0.05), indicating that while PAS staining revealed that the KD and LCD increased and bacterial motility proteins and bacterial chemotaxis were over- decreased the number of goblet cells in the colon compared to represented in the microbiome of the LCD group compared to the the ND, respectively (Fig. 3k). KD ketogenic diet, LCD low-carbohydrate diet, ND normal diet, DSS dextran sulfate sodium, DAI disease activity index, IHC immunohistochemistry, PAS periodic acid schiff recipient mice, whereas 78 ND OTUs were present (Fig. S3 and Supplementary Table 3) These results demonstrate that a significant proportion of OTUs successfully colonized the gut of recipient mice, validating the reliability of FMT

DISCUSSION

MATERIALS AND METHODS

Findings

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