Dietary Yeasts Reduce Inflammation in Central Nerve System via Microflora

Area of Science:

• Immunology
• Microbiome Research
• Neuroscience

Background:

• The gut microbiome influences autoimmune disease pathogenesis.
• Lactic acid bacteria show immune benefits, but yeast effects are less understood.
• Investigating dietary yeasts for autoimmune conditions like multiple sclerosis (MS) is crucial.

Purpose of the Study:

• To explore the impact of dietary yeasts from fermented foods on experimental autoimmune encephalomyelitis (EAE), an animal model for MS.
• To identify specific yeasts with therapeutic potential.
• To elucidate the underlying mechanisms of yeast-mediated immune modulation.

Main Methods:

• Eight yeasts were screened in an EAE model.
• Candida kefyr was further analyzed for its effects on gut microbiota and immune responses.
• Immune cell populations (Th17, Tregs, dendritic cells) and cytokine production were assessed.
• Fecal 16S rRNA gene sequencing was used to profile the gut microbiota.

Main Results:

• Candida kefyr administration significantly ameliorated EAE severity.
• C. kefyr treatment led to increased regulatory T cells (Tregs) and CD103-positive regulatory dendritic cells in mesenteric lymph nodes.
• A decrease in Th17 cells and suppressed IL-6 production were observed in the intestinal lamina propria.
• Microbiota analysis revealed an increase in Lactobacillales and a decrease in Bacteroides following C. kefyr treatment.
• Transfer of microbiota from C. kefyr-treated mice also reduced Bacteroides and improved EAE symptoms.

Conclusions:

• Oral intake of Candida kefyr demonstrates therapeutic potential for MS by modulating the gut microbiota.
• The beneficial effects are associated with enhanced regulatory immune cells and altered microbial composition.
• Dietary yeasts represent a promising avenue for developing novel strategies for autoimmune diseases.