Vitamin D influences gut microbiota and acetate production in zebrafish (Danio rerio) to promote intestinal immunity against invading pathogens

ABSTRACT

Although evidence has shown that vitamin D (VD) influences gut homeostasis, limited knowledge is available how VD regulates intestinal immunity against bacterial infection. In the present study, cyp2r1 mutant zebrafish, lacking the capacity to metabolize VD, and zebrafish fed a diet devoid of VD, were utilized as VD-deficient animal models. Our results confirmed that the expression of antimicrobial peptides (AMPs) and IL-22 was restrained and the susceptibility to bacterial infection was increased in VD-deficient zebrafish. Furthermore, VD induced AMP expression in zebrafish intestine by activating IL-22 signaling, which was dependent on the microbiota. Further analysis uncovered that the abundance of the acetate-producer Cetobacterium in VD-deficient zebrafish was reduced compared to WT fish. Unexpectedly, VD promoted the growth and acetate production of Cetobacterium somerae under culture in vitro. Importantly, acetate treatment rescued the suppressed expression of β-defensins in VD-deficient zebrafish. Finally, neutrophils contributed to VD-induced AMP expression in zebrafish. In conclusion, our study elucidated that VD modulated gut microbiota composition and production of short-chain fatty acids (SCFAs) in zebrafish intestine, leading to enhanced immunity.

KEYWORDS:

• Short-chain fatty acids
• microbiota
• vitamin D₃
• antimicrobial peptides
• IL-22
• defensin
• Cetobacterium
• acetate
• neutrophil

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

Statement of ethics

Husbandry and handling of the fish in the present study were approved by the Experimental Animal Ethics Committee of Ocean University of China, and the procedures were performed strictly according to the Management Rule of Laboratory Animals (Chinese order no. 676 of the State Council, revised on 1 March, 2017).

Author contributions

XL designed and performed the experiments, analyzed the data, and wrote the manuscript; YL designed and performed the experiments, and analyzed the data; WW, JZ, RS performed the experiments; ZY generated cyp2r1 KO zebrafish and revised the manuscript; GHG and PB supervised the project and revised the manuscript; KM and QA supervised the project; MW supervised the project, designed the experiments, analyzed the data, and wrote the manuscript.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/19490976.2023.2187575.

Additional information

Funding

National Natural Science Foundation of China (31972802); Natural Science Foundation of Shandong Province (ZR2019MC041); National Key R&D Program of China (2018YFD0900400); Taishan Scholar Program of Shandong Province (tsqn201812023).