With the obesity epidemic and prevalence of 25%, metabolic dysfunction-associated steatotic liver disease (MASLD) is the most prevalent liver disease in the world. Despite the enormous economic and clinical burden that MASLD poses, there are still no approved therapies. Mechanisms regulating disease progression are largely unknown, but the crosstalk of liver and visceral adipose tissue (VAT) in the context of obesity, appears to be instrumental in driving the onset of steatosis and progression to metabolic dysfunction associated steatohepatitis (MASH) and fibrosis. This is also due to the role that VAT has in mediating immune modulation, inflammatory and metabolic alterations. The hypothesis is that VAT-driven intercellular communication involving hepatocytes and liver non-parenchymal cells (NPCs), has a significant role in MASLD progression. To study the liver-VAT axis in vitro, it is of utmost importance to reproduce the complex and multicellular nature of these tissues. Contrary to previous studies based on simplistic two-dimensional co-cultures of single cell types, XB-LIVAT proposes to use a holistic, interdisciplinary and translational approach to study liver-VAT axis. XB-LIVAT will use a novel co-culture system consisting of an advanced human hetero-cellular liver three-dimensional spheroid model and clinical VAT explants, together with state-of-the-art ‘omics’ technologies to unravel key cell players, early molecular events, and targets in MASLD. In combination with in-depth molecular analysis of MASLD liver biopsies, this advanced in vitro co-culture model with high translational value will shed light on molecular mechanisms in MASLD, with particular focus on the role of NPCs. In addition to contributing to the discovery of novel therapeutic targets and interventional approaches for improving the clinical management of MASLD, XB-LIVAT will shape the researcher into an expert in advanced in vitro disease modeling and translational hepatology.