Metabolic reprograming of immune cells in MASH

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as nonalcoholic fatty liver disease (NAFLD), affects approximately 30% of adults worldwide. Approximately 1/6 of MASLD patients progress to metabolic dysfunction-associated steatohepatitis (MASH) and potentially evolve towards cirrhosis and hepatocellular carcinoma (HCC). This condition imposes a significant burden on the global health. Although MASH is primarily a metabolic disorder, immune cells play a crucial role in its development. The activation of immune cells involves alterations in transcription and protein synthesis, which require metabolic adaptation of cellular substrate metabolism, including glucose and lipid metabolism. Moreover, the lipid-rich environment of the liver can affect the metabolism of immune cells. In this review, we delineate the metabolic profiles of immune cells in MASH, focusing on macrophages and T cells, and discuss the impact of targeting cellular metabolism on these cells along with clinical trial outcomes. Macrophages in MASH are characterized by increased glycolysis, compromised oxidative phosphorylation, and augmented lipid uptake, synthesis, and fatty acid oxidation, all of which contribute to their inflammatory phenotype. Lymphocytes, such as T cells and NK cells, exhibit impaired metabolic functions that hamper their immune surveillance capabilities and facilitate the development of HCC. However, research on the metabolic characteristics of other types of immune cells remains limited. With the development of single-cell genomics and animal models of MASH, we anticipate that further studies in this compelling field may shed light on the pathogenesis of MASH and pave the way for novel therapeutic strategies.