An Integrated Analysis to Understand the Dysregulation of Innate Immune Response in Mouse Models of MASLD

Background: Dysregulation of innate immune pathways is an important contributor to the progression of metabolic dysfunction-associated steatotic liver disease (MASLD). Inflammasomes serve as key regulators of innate immunity. Emerging evidence suggests that nutrient status, particularly choline, may play an important role in inflammasome activation. However, there is no systematic study across different in vitro and in vivo experiments to demonstrate the same. Methods: Hepatic expression of canonical inflammasomes such as NLRP3, NLRC4, and AIM2 and downstream inflammatory cytokines was analyzed in the high-fat-high-fructose (HF-HF) and methionine-choline-deficient (MCD) diet-induced mouse models of MASLD, along with liver biopsies from MASLD patients (n = 20). Moreover, in vitro experiments were performed to analyze the potential of choline to modulate inflammasome activation under obesogenic conditions. Results: Our data suggest increased hepatic expression of IL-1β and IL-18, at both mRNA and protein levels, in both models. While MCD-fed mice showed elevated hepatic mRNA expression of all three inflammasomes, the HF-HF diet induced a selective upregulation of NLRP3. Consistently, MCD-fed mice showed stronger induction of IL-1β and IL-18. MASLD patients also demonstrated increased hepatic expression of inflammasomes and both cytokines. In vitro, choline supplementation attenuated free fatty acid- and fructose-induced cytokine elevation. Conclusions: Our data suggest the differential activation of canonical inflammasomes across experimental MASLD models. We also observed that choline availability can serve as a potential modulator of metabolic stress-induced inflammation, highlighting the importance of nutrient status in metabolic liver disease.