Diagnosis and Mechanism of <scp>miR</scp> ‐1224‐5p in Children With <scp> <i>Mycoplasma pneumoniae</i> </scp> Pneumonia Complicated by Digestive System Damage

Pediatric Mycoplasma pneumoniae pneumonia (MPP) is often complicated by digestive system damage (DSD), with unclear mechanisms and biomarkers. The role of miR-1224-5p in this remains unknown. To explore the diagnostic value, mechanism, and role of miR-1224-5p in lung-gut axis injury in MPP + DSD. Bioinformatics analysis screened miR-1224-5p. Serum levels were detected via RT-qPCR in 120 MPP children (57 with DSD) and 81 controls. ROC curves and logistic regression assessed its diagnostic value. LAMPs-induced cell models and co-cultures were used to explore the mechanisms. GO/KEGG-analyzed pathways. Dual-luciferase assay was used to verify the binding relationship of the target. Serum miR-1224-5p was significantly upregulated in MPP children, especially in those complicated by DSD. MiR-1224-5p showed good diagnostic efficacy for MPP and MPP + DSD, and was an independent risk factor for DSD. In LAMPs-induced BEAS-2B cells and co-culture systems, miR-1224-5p expression was upregulated, while its inhibition reduced apoptosis and the secretion of inflammatory factors (IL-6, IL-1β, TNF-α). Its predicted target genes are involved in endothelial barrier, and GRB2 is a target of miR-1224-5p. MiR-1224-5p is a potential biomarker for MPP + DSD, and it participates in lung-gut injury by regulating inflammation/barrier function.