NUAK1 promotes metabolic dysfunction-associated steatohepatitis progression by activating Caspase 6-driven pyroptosis and inflammation.

Background: lNUAK1 is strongly associated with organ fibrosis, but its causal mechanism for modulating lipid metabolism and hepatic inflammation underlying MASH has not been fully clarified.

Method: In our study, human liver tissues from patients with MASH and control subjects were obtained to evaluate NUAK1 expression. MASH models were established using C57BL/6 mice. Liver damage and molecular mechanisms of the NUAK1-Caspase 6 signaling were tested in vivo and in vitro.

Results: In the clinical arm, NUAK1 expression was upregulated in liver samples from patients with MASH. Moreover, increased NUAK1 was detected in mouse MASH models. NUAK1 inhibition ameliorated steatohepatitis development in MASH mice accompanied by the downregulation of hepatic steatosis and fibrosis. Intriguingly, NUAK1 was found to facilitate Caspase 6 activation and trigger pyroptosis in MASH-stressed livers. Disruption of hepatocytes Caspase 6 decreased MASH-induced liver inflammation with upregulated TAK1 but diminished RIPK1. Moreover, we found that NUAK1/Caspase 6 axis inhibition could accelerate the interaction between TAK1 and RIPK1, which in turn led to the degradation of RIPK1.

Conclusions: In summary, our study elucidates that NUAK1-Caspase 6 signaling controls inflammation activation in MASH through the interaction between TAK1 and RIPK1, which is crucial for controlling pyroptosis and promoting the progression of MASH.