Ursodeoxycholyl lysophosphatidylethanolamide inhibits lipoapoptosis by shifting fatty acid pools toward monosaturated and polyunsaturated fatty acids in mouse hepatocytes

Mol Pharmacol. 2013 Nov;84(5):696-709. doi: 10.1124/mol.113.088039. Epub 2013 Aug 23.

Abstract

Ursodeoxycholyl lysophosphatidylethanolamide (UDCA-LPE) is a hepatoprotectant in inhibiting apoptosis, inflammation, and hyperlipidemia in mouse models of nonalcoholic steatohepatitis (NASH). We studied the ability of UDCA-LPE to inhibit palmitate (Pal)-induced apoptosis in primary hepatocytes and delineate cytoprotective mechanisms. We showed that lipoprotection by UDCA-LPE was mediated by cAMP and was associated with increases in triglycerides (TGs) and phospholipids (PLs). An inhibitor of cAMP-effector protein kinase A partially reversed the protective effects of UDCA-LPE. Lipidomic analyses of fatty acids and PL composition revealed a shift of lipid metabolism from saturated Pal to monounsaturated and polyunsaturated fatty acids, mainly, oleate, docosapentaenoate, and docosahexaenoate. The latter two ω-3 fatty acids were particularly found in phosphatidylcholine and phosphatidylserine pools. The catalysis of Pal by stearoyl-CoA desaturase-1 (SCD-1) is a known mechanism for the channeling of Pal away from apoptosis. SCD-1 protein was upregulated during UDCA-LPE lipoprotection. SCD-1 knockdown of Pal-treated cells showed further increased apoptosis, and the extent of UDCA-LPE protection was reduced. Thus, the major mechanism of UDCA-LPE lipoprotection involved a metabolic shift from toxic saturated toward cytoprotective unsaturated fatty acids in part via SCD-1. UDCA-LPE may thus be a therapeutic agent for treatment of NASH by altering distinct pools of fatty acids for storage into TGs and PLs, and the latter may protect lipotoxicity at the membrane levels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects*
  • Cyclic AMP / physiology
  • Cytoprotection
  • Fatty Acids / analysis
  • Fatty Acids / metabolism*
  • Hepatocytes / metabolism*
  • Lysophospholipids / pharmacology*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Stearoyl-CoA Desaturase / physiology
  • Ursodeoxycholic Acid / pharmacology*

Substances

  • Fatty Acids
  • Lysophospholipids
  • lysophosphatidylethanolamine
  • Ursodeoxycholic Acid
  • Cyclic AMP
  • Scd1 protein, mouse
  • Stearoyl-CoA Desaturase