Strain specific differences in vitamin D3 response: impact on gut homeostasis

Area of Science:

• Immunology
• Gastroenterology
• Nutritional Science

Background:

• Vitamin D3 is crucial for calcium metabolism and also influences immune function, gut barrier integrity, and microbiome composition.
• Emerging evidence suggests vitamin D3 plays a role in immune regulation and gut homeostasis beyond its classical functions.

Purpose of the Study:

• To investigate the impact of vitamin D3-fortified diets on gut homeostasis and immune cells in C57BL/6 and BALB/c mice.
• To explore strain-specific differences in vitamin D3 responsiveness in vivo and in vitro.

Main Methods:

• Administration of vitamin D3-containing diets to C57BL/6 and BALB/c mice.
• Analysis of immune cell populations (e.g., T cells, myeloid cells) in spleen and Peyer's Patches.
• Assessment of gene and protein expression related to gut homeostasis (e.g., Mucin Reg3γ, Batf) in the small intestine.
• In vitro analysis of cytokine secretion (IFN, GM-CSF, IL-10) by murine T cells.
• Gut microbiome profiling.

Main Results:

• Vitamin D3 supplementation led to tissue-specific enrichment of myeloid cells, but not T cells, in both mouse strains.
• High vitamin D3 diets suppressed key gut homeostasis proteins (Reg3γ, Batf) in C57BL/6 mice but not BALB/c mice.
• In vitro, 1,25-dihydroxyvitamin D3 tended to suppress cytokine secretion in T cells from C57BL/6 mice, but not BALB/c mice.
• Vitamin D3 impacted the gut microbiome in C57BL/6 mice, but not BALB/c mice.
• Vitamin D3 receptor expression was high in epithelial cells of both strains, suggesting other factors mediate strain-specific responses.

Conclusions:

• Significant strain-specific differences exist in vitamin D3 responsiveness in mice under steady-state conditions.
• These findings underscore the importance of considering mouse strain when designing studies on vitamin D3's role in immunity and gut health.
• The observed variations may influence the interpretation of results in preclinical models of disease.