Chronic low-dose of BPS and PFOS alter adipogenic programming and impair insulin responsiveness in human adipocytes

Background and aim: obesity is a major global health concern tightly linked to insulin resistance and type 2 diabetes. Environmental exposure to endocrine-disrupting chemicals (EDs), including bisphenols (BPs) and perfluoroalkyl substances (PFs), has been implicated in metabolic dysfunction, yet the impact of chronic low-dose co-exposure on human adipocyte development and insulin responsiveness remains poorly defined. Here, we evaluated bisphenol S (BPS) and perfluorooctane sulfonate (PFOS), alone or combined, in human adipose-derived stem cells undergoing adipogenic differentiation. Methods: Cells were chronically exposed to environmentally relevant low doses of bisphenol S (BPS) and perfluorooctane sulfonate (PFOS), alone or in combination, throughout adipogenic differentiation. Results: Lipid droplet accumulation was unchanged across conditions, indicating preserved terminal differentiation. In contrast, BPS and PFOS altered the timing and magnitude of key adipogenic transcriptional programs (CEBPA, PPARγ) and the mature adipocyte marker FABP4. PFOS and BPS+PFOS selectively increased IL1β expression in mature adipocytes, suggesting a limited pro-inflammatory shift. Functionally, all ED-treated groups showed reduced insulin-stimulated glucose uptake, associated with impaired GLUT4 translocation to the plasma membrane despite unchanged total GLUT4 levels. Notably, combined exposure produced the strongest defects in insulin signalling, reducing PI3K pathway activation and decreasing total AKT and ERK1/2 protein levels. In contrast, individually administered BPS and PFOS impaired glucose uptake without detectable PI3K alterations, suggesting the involvement of additional mechanisms. Conclusion: Overall, chronic low-dose exposure to BPS and PFOS disrupts adipocyte transcriptional and signalling networks, inducing features consistent with impaired insulin responsiveness and underscoring the importance of considering ED mixtures in metabolic risk assessment.