Endocrine Abstracts

JOINT1641

Background: Polycystic ovary syndrome (PCOS), characterized by hyperandrogenism, is the leading cause of female infertility and is associated with insulin resistance and type 2 diabetes. Impaired adipose tissue function is a key determinant of the metabolic phenotype in PCOS, with dysfunction evident in altered lipid metabolism, energy homeostasis, and adipokine production. Our group has identified enlarged fat cells as drivers of insulin resistance and linked aberrant genetic and epigenetic expression in adipose tissue to PCOS-related metabolic disturbances. However, the molecular mechanisms remain poorly understood and are not addressed by current drug development. Treatment for insulin-resistant PCOS primarily focuses on symptom management through lifestyle changes, diet, exercise, and antidiabetic drugs, including metformin and GLP1 receptor agonists. Yet, their direct effects on adipocytes in PCOS remain unclear. To address this, we are generating a single-nuclei transcriptome atlas of subcutaneous adipose tissue from women with and without PCOS to identify disease- and cell type-specific signatures and treatment responses (see abstract Li et al). In parallel, we are developing and characterizing 2D and 3D in vitro adipose tissue cultures to investigate adipogenic differentiation, adipose dysfunction, and drug responses, focusing on metformin and GLP1-RA (semaglutide).

Methods: We collect subcutaneous white adipose tissue from hyperandrogenic, insulin-resistant women with PCOS and age and BMI-matched controls. Fresh biopsies are used to isolate adipose stem cells (ASCs) to assess adipogenic capacity, tissue recapitulation, and responses to metformin and semaglutide. We perform bulk RNA sequencing at day 0 (ASC), day 6 (preadipocytes), and day 12 (mature adipocytes). Moreover, we analyse lipid accumulation ad lipid droplet size, basal and stimulated lipolysis, and bioenergetics using Seahorse XFe96. Additionally, 3D adipocyte spheroids are generated and characterized.

Results & Future Perspectives:: Preliminary data indicate that 2D-differentiated PCOS adipocytes retain larger lipid droplets, mimicking tissue biopsies. PCOS adipocytes exhibit lower basal oxygen consumption and higher basal lipolysis, both partially reversed by metformin and semaglutide. Bulk RNA sequencing reveals persistent PCOS-specific differential gene expression related to mitochondrial function throughout differentiation. Preliminary 3D spheroid data suggest similar lipid droplet enlargement. Ongoing work includes profiling the secretome and extracellular vesicles and comparing transcriptomic data from in vitro and freshly isolated mature adipocytes for model validation and with single nuclei RNA-seq data. Future efforts aim to develop advanced in vitro PCOS models, such as microfluidic co-culture systems integrating adipose and reproductive tissues, including endometrial epithelial organoids and stromal cells, to study tissue interactions in PCOS.