• circDCBLD2 is downregulated in CD4+ T cells from asthmatic patients and OVA-induced asthmatic mice, correlating with Th1/Th2 cytokine imbalance.
• Overexpression of circDCBLD2 shifts the immune balance toward Th1, reducing Th2 responses and alleviating asthma symptoms in mice.
• Mechanistically, circDCBLD2 acts as a sponge for miR-26a-5p, which targets PTEN, revealing a novel regulatory axis in asthma pathogenesis.
• The circDCBLD2/miR-26a-5p/PTEN axis offers a promising therapeutic target for asthma immunotherapy.