Phosphatidylglycerol Incorporates into Cardiolipin to Improve Mitochondrial Activity and Inhibits Inflammation

Sci Rep. 2018 Mar 20;8(1):4919. doi: 10.1038/s41598-018-23190-z.

Abstract

Chronic inflammation and concomitant oxidative stress can induce mitochondrial dysfunction due to cardiolipin (CL) abnormalities in the mitochondrial inner membrane. To examine the responses of mitochondria to inflammation, macrophage-like RAW264.7 cells were activated by Kdo2-Lipid A (KLA) in our inflammation model, and then the mitochondrial CL profile, mitochondrial activity, and the mRNA expression of CL metabolism-related genes were examined. The results demonstrated that KLA activation caused CL desaturation and the partial loss of mitochondrial activity. KLA activation also induced the gene upregulation of cyclooxygenase (COX)-2 and phospholipid scramblase 3, and the gene downregulation of COX-1, lipoxygenase 5, and Δ-6 desaturase. We further examined the phophatidylglycerol (PG) inhibition effects on inflammation. PG supplementation resulted in a 358-fold inhibition of COX-2 mRNA expression. PG(18:1)2 and PG(18:2)2 were incorporated into CLs to considerably alter the CL profile. The decreased CL and increased monolysocardiolipin (MLCL) quantity resulted in a reduced CL/MLCL ratio. KLA-activated macrophages responded differentially to PG(18:1)2 and PG(18:2)2 supplementation. Specifically, PG(18:1)2 induced less changes in the CL/MLCL ratio than did PG(18:2)2, which resulted in a 50% reduction in the CL/MLCL ratio. However, both PG types rescued 20-30% of the mitochondrial activity that had been affected by KLA activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cardiolipins / metabolism*
  • Cyclooxygenase 2 / genetics
  • Cyclooxygenase 2 / metabolism
  • Gene Expression Regulation
  • Inflammation / metabolism*
  • Lipopolysaccharides / metabolism
  • Lysophospholipids / metabolism*
  • Macrophage Activation
  • Macrophages / physiology*
  • Mice
  • Mitochondria / metabolism*
  • Mitochondrial Membranes / metabolism*
  • Phosphatidylglycerols / metabolism*
  • RAW 264.7 Cells

Substances

  • Cardiolipins
  • Kdo2-lipid A
  • Lipopolysaccharides
  • Lysophospholipids
  • Phosphatidylglycerols
  • monolysocardiolipin
  • Cyclooxygenase 2