OR20-03 Transcriptional Changes in Lipid Metabolism of Adipocytes Derived from Subcutaneous Abdominal Adipose Stem Cells of Normal-Weight Polycystic Ovary Syndrome Women

Abstract

Normal-weight polycystic ovary syndrome (PCOS) women exhibit increased adipose insulin resistance in vivo (1) accompanying enhanced subcutaneous (SC) abdominal adipose stem cell (ASC) development to adipocytes with greater lipid accumulation per cell in vitro (2). To determine whether this phenomenon is associated with abnormal adipogenic gene transcription during ASC differentiation into adipocytes, SC abdominal ASCs isolated from three non-Hispanic Caucasian normal-weight PCOS women and three age- and BMI-matched controls were cultured in adipogenic differentiation medium for 3–12 days. After RNA isolation, gene expression levels were determined by RNA sequencing at days 3, 7, and 12. Differentially expressed genes were filtered for significance (padj<0.05) and fold change (>2-fold); upstream regulator genes and gene ontology (GO) functions were determined using Ingenuity Pathway Analysis. Gene set enrichment analysis (GSEA) also was used to identify enriched cellular processes (3). Differentially expressed genes in PCOS vs. control cells were either upregulated (466, 768 and 441 genes on days 3, 7 and 12, respectively) or downregulated (742, 974 and 605 genes on days 3, 7 and 12, respectively) over time, with critical genes governing adipocyte cell differentiation in PCOS cells increased 2–6 fold at days 3, 7 and 12 (PPARγ, CEBPα, ADIPOQ, AGPAT2, FABP4, LPL, PLIN1). The predicted upstream regulator genes TGFβ1 (an adipogenic inhibitor) and TNF (a pro-inflammatory adipokine) were significantly reduced in PCOS relative to control cells at all time points. The GO functions lipid oxidation and free fatty acid (FFA) beta-oxidation were enriched amongst upregulated genes in PCOS cells across all time points, while acylglycerol synthesis was increased at days 7 and 12 alone (z>2, p<0.05, all GO functions). In parallel, GSEA showed in PCOS cells significantly increased transcripts related to oxidative phosphorylation, peroxisome activity and adipogenesis at all time points (p<0.05). Thus, adipocytes derived from SC abdominal ASCs of normal-weight PCOS women exhibit early activation of adipogenic genes, potentially underlying their exaggerated lipid accumulation in vitro, as previously described (2). These PCOS-related changes in gene expression involve an increase in both oxidative phosphorylation and FFA beta oxidation, which could disrupt the balance between energy production and lipid storage, particularly when caloric intake exceeds energy utilization.