Inflammation and polyendocrine metabolic ovarian syndrome: Utilising proteomics to unravel this link in adolescents

Purpose and Methods PMOS affects 10-26% of adolescent females. Yet, its pathogenesis is poorly understood. Proteomics is a valuable tool to explore biological pathways underpinning PMOS, and identify novel diagnostic/monitoring biomarkers. We undertook deep-phenotyping discovery proteomic profiling (nano-2D-LC-QTOF MSe) on urine samples from a subset of a longitudinal adolescent PMOS cohort (n = 40). We compared the urinary proteome of adolescents (12-19 years, ≥1-year post-menarche) recruited from adolescent endocrinology/gynaecology clinics with PMOS or insulin resistance (IR), and community-recruited age/sex/puberty-matched controls. PMOS was defined by adolescent-specific criteria (irregular menstrual cycles and hyperandrogenism). Exclusion criteria included the combined oral contraceptive pill. Results were validated in the whole cohort with a multiplexed targeted proteomic panel. Results Discovery proteomic analysis identified 3,793 proteins, of which 66 were differentially expressed in the PMOS cohort versus IR and controls - candidate PMOS biomarkers. Bioinformatic analysis revealed that almost half of the PMOS-associated biological pathways were related to inflammatory/immunological responses. The inflammatory response was the most significant biological process (p < 0.001). Targeted proteomic analysis of 89 known inflammatory-associated proteins validated this association. Multivariate analysis demonstrated a distinct inflammatory proteome in adolescent PMOS. Twenty inflammatory-associated proteins were differentially expressed in the PMOS cohort versus IR/controls, with notable roles in oxidative stress and neuroinflammation. Six proteins were significantly different in PMOS in comparison to both IR/control cohorts. Conclusion These analyses provide insight into the pathophysiology of PMOS, highlighting inflammatory processes as a prominent feature of adolescent PMOS and identifying several candidate novel non-invasive biomarkers and drug targets to further validate.