Circular RNA circFADS2 is overexpressed in sepsis and suppresses LPS-induced lung cell apoptosis by inhibiting the maturation of miR-15a-5p

BACKGROUND: Circular RNA circFADS2 plays protective roles in LPS-induced inflammation, which promotes sepsis, suggesting its involvement in sepsis. METHODS: Expression of circFADS2, mature miR-15a-5p, and miR-15a-5p precursor in plasma samples from sepsis patients and healthy controls was determined by RT-qPCR. The circFADS2 expression vector was transfected in lung cells, followed by the measurement of the expression levels of mature miR-15a-5p and miR-15a-5p precursor to study the role of circFADS2 in miR-15a-5p maturation. Cell apoptosis was analyzed by cell apoptosis assay. RESULTS: CircFADS2 was upregulated in sepsis and inversely correlated with mature miR-15a-5p, but not miR-15a-5p precursor. In lung cells, circFADS2 overexpression decreased the level of mature miR-15a-5p, but not miR-15a-5p precursor. LPS treatment decreased miR-15a-5p expression and increased circFADS2 level. Cell apoptosis analysis showed that circFADS2 overexpression reduced miR-15a-5p overexpression-induced apoptosis of LPS-treated lung cells. CONCLUSIONS: CircFADS2 is upregulated in sepsis to suppress LPS-induced lung cell apoptosis by inhibiting miR-15a-5p maturation.