Vitamin D Enhances Neutrophil Generation and Function in Zebrafish (Danio rerio)

• Published in: Journal of innate immunity 2022, Vol.14 (3), p.229-242
• Main Authors: Liao, Xinmeng, Lan, Yawen, Shao, Rui, Liu, Jiayu, Liang, Shufei, Yin, Zhan, Gudmundsson, Gudmundur H., Bergman, Peter, Wan, Min
• Format: Article
• Language: English
• Subjects: Animals; granulopoiesis; infection; Larva; Medicin och hälsovetenskap; microbiota; Neutrophil Infiltration; neutrophil recruitment; Neutrophils; Research Article; Vitamin D - metabolism; Vitamin D - pharmacology; vitamin d3; Zebrafish
• ISSN: 1662-811X; 1662-8128; 1662-8128
• DOI: 10.1159/000519183

Vitamin D (VD) is a major regulator of calcium metabolism in many living organisms. In addition, VD plays a key role in regulating innate and adaptive immunity in vertebrates. Neutrophils constitute an important part of the first line of defense against invading microbes; however, the potential effect of VD on neutrophils remains elusive. Thus, in this study zebrafish in different developmental stages were utilized to identify the potential role of VD in the basal homeostasis and functions of neutrophils. Our results showed that addition of exogenous VD 3 promoted granulopoiesis in zebrafish larvae. Reciprocally, neutrophil abundance in the intestine of adult zebrafish with a cyp2r1 mutant, lacking the capacity to 25-hydroxylate VD, was reduced. Moreover, VD-mediated granulopoiesis was still observed in gnotobiotic zebrafish larvae, indicating that VD regulates neutrophil generation independent of the microbiota during early development. In contrast, VD was incapable to influence granulopoiesis in adult zebrafish when the commensal bacteria were depleted by antibiotic treatment, suggesting that VD might modulate neutrophil activity via different mechanisms depending on the developmental stage. In addition, we found that VD 3 augmented the expression of il-8 and neutrophil recruitment to the site of caudal fin amputation. Finally, VD 3 treatment significantly decreased bacterial counts and mortality in zebrafish infected with Edwardsiella tarda (E. tarda) in a neutrophil-dependent manner. Combined, these findings demonstrate that VD regulates granulopoiesis and neutrophil function in zebrafish immunity.