HLA-DRB1 and major depressive disorder: Network pharmacology was utilized to decode the associations between metabolic biomarkers and depression, and 9 metabolite targets correlated with the neurological, immune, and endocrine systems are potential drug targets for the treatment of depression, including PTEN, TP53, HLA-DRB1, bIL1B, TNF, HRAS, MTOR, PIK3CA, and INS [80].