Linear ubiquitination prevents lipodystrophy and obesity-associated metabolic syndrome

Adipocyte hypertrophy during obesity triggers chronic inflammation, leading to metabolic disorders. However, the role of adipocyte-specific inflammatory signalling in metabolic syndrome remains unclear. The linear ubiquitin chain assembly complex, LUBAC, is an E3-ligase that generates non-degradative linear ubiquitination (Lin-Ub). LUBAC regulates NF-B/MAPK-driven inflammation and prevents cell death triggered by immune receptors like TNF-receptor-1. Here we show that mice lacking HOIP, LUBACs catalytic subunit, in adipocytes (HoipA-KO) display lipodystrophy and heightened susceptibility to obesity-induced metabolic syndrome, particularly Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD). Mechanistically, loss of HOIP attenuates TNF-induced NF-B activation and promotes cell death in human adipocytes. Inhibiting caspase-8-mediated cell death is sufficient to prevent lipodystrophy and MASLD in HoipA-KO obese mice. Importantly, HOIP expression in adipose tissue positively correlates with metabolic fitness in obese individuals. Overall, our findings reveal a fundamental developmental role for Lin-Ub in adipocytes by mitigating cell death-driven adipose tissue inflammation and protecting against obesity-related metabolic