Orai2 deficiency attenutates experimental colitis by facilitating the colonization of Akkermansia muciniphila

Area of Science:

• Immunology
• Microbiology
• Gastroenterology

Background:

• Orai2 is crucial for store-operated Calcium channels (SOCCs) and immune function.
• Intestinal macrophages (Mφs) play a key role in maintaining gut homeostasis.
• Dysregulation of calcium signaling is implicated in inflammatory conditions like colitis.

Purpose of the Study:

• To investigate the role of Orai2 in intestinal macrophages during experimental colitis.
• To elucidate the molecular mechanisms linking Orai2 deficiency to gut inflammation and microbial changes.
• To explore Orai2 as a potential therapeutic target for colitis.

Main Methods:

• Orai2 knockout (Orai2^-/-) mouse model of experimental colitis.
• 16S rRNA sequencing for gut microbiota analysis.
• Untargeted metabolomics to profile lipid derivatives.
• Pharmacological inhibition of Pla2g6.

Main Results:

• Orai2 deficiency ameliorated colitis, reducing colonic damage and pro-inflammatory cytokines.
• Orai2 knockout led to increased Akkermansia muciniphila abundance and altered lipid metabolism (Pla2g6, Alox5).
• Pla2g6 inhibition in Orai2^-/- mice reduced A. muciniphila and normalized calcium channel activity.

Conclusions:

• Orai2 deficiency in intestinal Mφs promotes A. muciniphila colonization via Pla2g6 upregulation.
• This Orai2-Pla2g6-A. muciniphila axis ameliorates experimental colitis.
• Targeting Orai2 signaling represents a potential therapeutic strategy for colitis.