Iron overload in steatotic hepatocytes drives systemic metabolic dysfunction via alterations in hepatokine production.

Abstract

Iron overload has emerged as a significant risk factor for metabolic dysfunction-associated steatotic liver disease (MASLD), a growing global health concern. Despite this association, the precise mechanisms by which hepatic iron and its regulatory genes connect liver pathology to systemic metabolic dysfunction remain elusive. Here, we demonstrate that humoral signals originating from iron-overloaded hepatocytes act as critical mediators driving systemic metabolic dysfunction in MASLD. Ferroportin (FPN, SLC40A1), the sole cellular iron exporter, exhibits markedly reduced expression in hepatocytes of both human patients and mouse models with MASLD, concomitant with hepatic iron accumulation. Functionally, hepatocyte-specific FPN deletion significantly exacerbates diet-induced obesity and insulin resistance, with these metabolic perturbations accompanied by decreased energy expenditure and impaired thermogenic capacity. Mechanistically, we establish that hepatic iron accumulation resulting from FPN deficiency enhances the production of two specific hepatokines, Fetuin-A and LECT2, through activation of the transcription factor FoxO1. Notably, therapeutic interventions - including genetic silencing of these hepatokines, hepatocyte-specific FPN overexpression, or oral iron chelation - effectively reverse the metabolic dysfunction phenotypes. These findings provide critical insights into the pathophysiological mechanisms linking MASLD to systemic metabolic disorders and highlight promising therapeutic strategies to combat these diseases.