Hepatic lysosomal acid lipase overexpression worsens hepatic inflammation in mice fed a Western diet.
Study Goal
The researchers aimed to determine whether overexpressing lysosomal acid lipase (LAL) in the livers of mice fed a Western diet could prevent the development of nonalcoholic fatty liver disease (NAFLD).
Results Summary
Mice fed the Western diet exhibited markers of NAFLD, including hepatomegaly, lipid accumulation, and inflammation. LAL overexpression did not reduce steatosis and worsened inflammation and immune cell infiltration, suggesting it may not be a viable treatment for NAFLD.
Population
Mice (animal model)
Effective Dosage
Not specified
Duration
Not specified
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Western diet | increase | numerous markers of NAFLD, including hepatomegaly, lipid accumulation, and inflammation | mice | - | exhibited | #1 |
LAL overexpression | no change | steatosis | mice fed the Western diet | - | did not attenuate | #2 |
LAL overexpression | no change | neutral lipid composition | mice fed the Western diet | - | had only minor effects on | #3 |
LAL overexpression | increase | inflammatory gene expression | mice fed the Western diet | - | exacerbated | #4 |
LAL overexpression | increase | infiltration of immune cells | mice fed the Western diet | - | exacerbated | #5 |
LAL overexpression | increase | abnormal phagosome accumulation | - | - | resulted in | #6 |
LAL overexpression | increase | lysosomal lipid accumulation | - | - | resulted in | #7 |
hepatic overexpression of LAL | increase | immune cell infiltration | - | - | drove | #8 |
hepatic overexpression of LAL | increase | inflammation | - | - | drove | #9 |
hepatic overexpression of LAL | no change | the development of NAFLD | - | - | did not attenuate | #10 |
Nonalcoholic fatty liver disease (NAFLD) is characterized by the accumulation of lipid droplets in hepatocytes. NAFLD development and progression is associated with an increase in hepatic cholesterol levels and decreased autophagy and lipophagy flux. Previous studies have shown that the expression of lysosomal acid lipase (LAL), encoded by the gene LIPA, which can hydrolyze both triglyceride and cholesteryl esters, is inversely correlated with the severity of NAFLD. In addition, ablation of LAL activity results in profound NAFLD. Based on this, we predicted that overexpressing LIPA in the livers of mice fed a Western diet would prevent the development of NAFLD. As expected, mice fed the Western diet exhibited numerous markers of NAFLD, including hepatomegaly, lipid accumulation, and inflammation. Unexpectedly, LAL overexpression did not attenuate steatosis and had only minor effects on neutral lipid composition. However, LAL overexpression exacerbated inflammatory gene expression and infiltration of immune cells in mice fed the Western diet. LAL overexpression also resulted in abnormal phagosome accumulation and lysosomal lipid accumulation depending upon the dietary treatment. Overall, we found that hepatic overexpression of LAL drove immune cell infiltration and inflammation and did not attenuate the development of NAFLD, suggesting that targeting LAL expression may not be a viable route to treat NAFLD in humans.