Enzyme UBE2N identified as potential defense against fatty liver disease progression

Metabolic dysfunction-associated steatohepatitis (MASH) is a progressive liver disease with limited treatment options. Recent preclinical studies have identified promising therapeutic targets to halt its progression. Research co-led by Cedars-Sinai shows that restoring the enzyme UBE2N protects mouse livers by clearing damaged mitochondria and breaking down fat. Separately, Texas A&M researchers found that inhibiting the MAP4K4 protein with an experimental compound reduces fat, inflammation, and scarring. Additionally, a study in eGastroenterology links intestinal neutral ceramidase to gut barrier dysfunction that drives MASH, highlighting new therapeutic pathways across the gut-liver axis.

Role of UBE2N enzyme in MASH

• ▪Researchers found that UBE2N enzyme levels decline in liver cells as metabolic dysfunction-associated steatohepatitis (MASH) becomes more advanced, leading to increased cell damage and liver injury.
• ▪A preclinical study co-led by Cedars-Sinai Health Sciences University identified UBE2N as a potential therapeutic target; restoring its levels in laboratory mice reduced fat accumulation, inflammation, and scarring, suggesting its potential to prevent MASLD from advancing to MASH.
• ▪The UBE2N enzyme protects the liver by facilitating the removal of damaged mitochondria and supporting the breakdown of fat, according to a study published in Nature Metabolism.

MAP4K4 protein and GPPD inhibitor

• ▪Researchers determined that MAP4K4 levels increase as MASH advances, suggesting it could serve as a promising therapeutic target.
• ▪In preclinical testing, the experimental compound GPPD simultaneously improved fat accumulation, inflammation, liver injury, and fibrosis while demonstrating an encouraging safety profile with no significant toxicity.
• ▪A study from the Texas A&M College of Veterinary Medicine and Biomedical Sciences identified the protein MAP4K4 as a central regulator of multiple disease-related processes in MASH.
• ▪An experimental small-molecule inhibitor called GPPD selectively blocks MAP4K4 activity without changing its overall levels, which may minimize unintended side effects while slowing MASH progression.

Role of intestinal neutral ceramidase

• ▪A study published in eGastroenterology identified intestinal neutral ceramidase, encoded by the Asah2 gene, as a gut-derived driver of MASH progression through its effects on microbial metabolism and epithelial signaling.
• ▪Mice with intestinal epithelial cell-specific deletion of the Asah2 gene were protected from diet-induced MASH, displaying less liver fibrosis, lower inflammatory injury, and improved gut barrier integrity.
• ▪Fecal microbiota transplantation from Asah2-deficient mice conferred protection against MASH in germ-free mice, demonstrating that intestinal neutral ceramidase shapes a disease-relevant microbial ecosystem.

Epithelial AhR signaling and barrier function

• ▪Intestinal epithelial AhR deficiency worsened MASH and reduced fucosylation, whereas fucoidan supplementation increased fucosylation, improved barrier function, and attenuated disease severity in mice.
• ▪Intestinal neutral ceramidase and epithelial AhR influence lung inflammation, supporting the existence of a gut-liver-lung axis in metabolic disease where microbial metabolites contribute to systemic immune activation.
• ▪Intestinal neutral ceramidase alters gut microbial composition to increase production of 2-hydroxyhippuric acid (2-HHA), which suppresses epithelial aryl hydrocarbon receptor (AhR) signaling and weakens mucosal barrier function.

Overview and prevalence of MASH

• ▪MASH has an estimated prevalence of 1% to 6% in the United States, which is projected to rise substantially over the next decade.
• ▪An estimated 100 million people in the United States have MASLD, and approximately 20% to 25% of those affected progress to develop MASH.
• ▪Metabolic dysfunction-associated steatohepatitis (MASH), formerly called nonalcoholic steatohepatitis (NASH), is the progressive form of metabolic dysfunction-associated steatotic liver disease (MASLD).
• ▪MASH is defined histologically by hepatic steatosis, lobular inflammation, and ballooning degeneration, which can progress to fibrosis, cirrhosis, liver failure, and liver cancer.

Treatment options for MASH

• ▪Treatment options for MASH remain limited, with current care mainly centering on lifestyle changes, efforts to limit additional liver damage, and no existing cure.
• ▪The thyroid hormone receptor-beta (THR-β) agonist resmetirom, approved by the FDA in March 2024, offers a liver-directed treatment specifically for MASH patients with moderate to severe fibrosis without cirrhosis.

Debatable claims

• ▪Healthcare providers should routinely screen asymptomatic patients with metabolic risk factors for MASH
• ▪Restoring intestinal homeostasis is more critical to treating MASH than reducing liver fat