(+)Alpha-Lipoic Acid Regulates Lipid Metabolism Gene Expression and Lipidic Profile in a Cellular Model of Fatty Acid Overload

Front Biosci (Landmark Ed). 2024 Jun 11;29(6):209. doi: 10.31083/j.fbl2906209.

Abstract

Background: Nonalcoholic fatty liver disease (NAFLD) is a prevalent condition characterized by hepatic fat accumulation, often progressing to severe liver injury, for which approved treatments are currently lacking. This study explores the potential therapeutic impact of alpha-lipoic acid (ALA), a natural compound crucial in lipid metabolism, on NAFLD using an in vitro model.

Methods: HepG2 cells were treated with a palmitic acid:oleic acid (PA:OA) mixture, representing a cellular model of steatosis. Subsequent treatment with ALA at concentrations of 1 µM and 5 µM aimed to evaluate its effects on lipid content and metabolism. Real-time polymerase chain reaction (PCR), BODIPY staining, cytofluorimetric analysis, and lipidomics were used to assess gene expression, lipid droplet accumulation, and fatty acid profiles.

Results: Our results showed that ALA significantly reduced lipid droplets in PA:OA-treated HepG2 cells, with a concentration-dependent effect. Analysis of fatty acid profiles demonstrated a decrease in palmitic acid levels with ALA treatment, while oleic acid reduction was observed only at the higher concentration. Moreover, ALA modulated the expression of genes involved in cholesterol biosynthesis and low-density lipoprotein (LDL) metabolism, indicating a potential role in lipid homeostasis. Further insights into molecular mechanisms revealed that ALA modulated peroxisome proliferator activated receptors (PPARs), specifically PPAR-alpha and PPAR-gamma, involved in fatty acid metabolism and insulin sensitivity. Finally, ALA counteracted the overexpression of thermogenic genes induced by exogenous fatty acids, suggesting a regulatory role in energy dissipation pathways.

Conclusion: In conclusion, this study highlights ALA as a therapeutic agent in mitigating lipid accumulation and dysregulation in NAFLD.

Keywords: fatty acid; lipid metabolism; lipoic acid; liver steatosis.

MeSH terms

  • Fatty Acids / metabolism
  • Gene Expression Regulation / drug effects
  • Hep G2 Cells
  • Humans
  • Lipid Droplets / drug effects
  • Lipid Droplets / metabolism
  • Lipid Metabolism* / drug effects
  • Non-alcoholic Fatty Liver Disease* / drug therapy
  • Non-alcoholic Fatty Liver Disease* / genetics
  • Non-alcoholic Fatty Liver Disease* / metabolism
  • Oleic Acid* / metabolism
  • Oleic Acid* / pharmacology
  • PPAR alpha / genetics
  • PPAR alpha / metabolism
  • PPAR gamma / metabolism
  • Palmitic Acid* / metabolism
  • Palmitic Acid* / pharmacology
  • Thioctic Acid* / pharmacology
  • Uncoupling Protein 2 / genetics
  • Uncoupling Protein 2 / metabolism

Substances

  • Thioctic Acid
  • Oleic Acid
  • Palmitic Acid
  • Fatty Acids
  • PPAR gamma
  • PPAR alpha
  • Uncoupling Protein 2