Asparagine-related biomarkers and regulatory mechanisms in type 2 diabetes mellitus.

Background: Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder. Emerging evidence suggests asparagine metabolism might play a pivotal role in T2DM, yet the underlying molecular mechanisms remain elusive. This study aimed to detect asparagine-related biomarkers and expound their functional roles in T2DM pathogenesis. Methods: Transcriptomic datasets from peripheral blood samples of T2DM patients and controls were analyzed. Differential expression analysis, protein-protein interaction (PPI) network, and machine learning algorithms, followed by expression analysis across cohorts were employed to screen biomarkers. Biomarker diagnostic performance was evaluated. Functional enrichment, immune infiltration analysis, and multi-layer regulatory network construction were conducted. Drug-target interactions and molecular docking were explored to identify potential therapeutics. Results: A total of 90 candidate genes were detected. Four feature genes were screened via multi-algorithm integration. Protein phosphatase 1 catalytic subunit alpha (PPP1CA) and cathepsin D (CTSD) were validated as biomarkers, showing significant upregulation in T2DM samples and high diagnostic accuracy (AUC of PPP1CA = 0.969 and CTSD = 0.984 in the training cohort, AUC of PPP1CA = 0.806 and CTSD = 0.875 in the validation cohort, respectively). Functional enrichment highlighted distinct yet complementary functional roles of PPP1CA and CTSD in T2DM progression. Immune infiltration revealed elevated activated dendritic cells, mast cells, and myeloid-derived suppressor cells in T2DM samples, with PPP1CA and CTSD correlating significantly with these cell types. Regulatory networks identified shared transcription factors and miRNAs targeting both genes. Pharmacological screening prioritized norcantharidin and naringenin as high-affinity compounds targeting these biomarkers. Conclusion: This study identified PPP1CA and CTSD as asparagine-related biomarkers driving immune-metabolic crosstalk in T2DM. The príicted regulatory networks and therapeutic compounds provided novel insights into T2DM mechanisms and potential intervention strategies.