Identification and Validation of ALOX15 as a Robust Diagnostic Biomarker for Obesity-Associated Asthma: An Integrative Bioinformatic and Experimental Study

Background: Obesity is a significant independent risk factor for asthma severity. However, the underlying molecular mechanisms by which it exacerbates asthma development remain unclear. This study aims to identify and validate key hub genes involved in high-fat diet-induced obesity aggravating asthma. Methods: Candidate genes associated with asthma, obesity, immunity, and inflammation were identified by integrating GEO databases (GSE76262, GSE41863, and GSE65204) with the GeneCards database. These candidate genes were further screened using three machine learning algorithms (LASSO, Random Forest, and SVM-RFE) followed by SHAP analysis. The expression of the hub gene ALOX15 and its correlation with pulmonary pathological changes were validated in a high-fat diet-induced asthma mouse model using qRT-PCR, Western Blot, and histological staining. Immune cell infiltration and functional pathways were explored using CIBERSORT, GSEA, and GSVA technologies. Results: Among 233 asthma differentially expressed genes, nine candidate genes associated with obesity, immunity, and inflammation were identified. Machine learning further identified ALOX15, IL1R1, TNFAIP3, and NLRP3 as diagnostic candidate genes, with ALOX15 demonstrating the most robust performance across multiple datasets (AUC > 0.7) and confirmed as the primary predictor via SHAP analysis. Animal experiments confirmed that a high-fat diet significantly exacerbated pulmonary inflammation and airway remodeling. ALOX15 expression in lung tissue was markedly higher in high-fat diet asthma model mice compared to normal diet asthma model mice. Functional analysis revealed a positive correlation between ALOX15 and eosinophil infiltration, with significant enrichment in arachidonic acid metabolism, NF-κB signaling pathways, and lipid metabolism processes. Conclusion: ALOX15 is a key molecular bridge in the pathogenesis of obesity-exacerbated asthma, linking high-fat diet-induced metabolic dysfunction to pro-inflammatory immune responses in the lungs, and may serve as a potential diagnostic biomarker and therapeutic target for obesity-associated asthma.