Maslinic acid modulates secreted phospholipase A2-IIA (sPLA2-IIA)-mediated inflammatory effects in macrophage foam cells formation

J Biosci. 2018 Jun;43(2):277-285.

Abstract

Secretory phospholipase A2-IIA (sPLA2-IIA) is one of the key enzymes causing lipoprotein modification and vascular inflammation. Maslinic acid is a pentacyclic triterpene which has potential cardioprotective and anti-inflammatory properties. Recent research showed that maslinic acid interacts with sPLA2-IIA and inhibits sPLA2-IIA-mediated monocyte differentiation and migration. This study elucidates the potential of maslinic acid in modulating sPLA2-IIA-mediated inflammatory effects in THP-1 macrophages. We showed that maslinic acid inhibits sPLA2-IIA-mediated LDL modification and suppressed foam cell formation. Further analysis revealed that sPLA2-IIA only induced modest LDL oxidation and that inhibitory effect of maslinic acid on sPLA2-IIA-mediated foam cells formation occurred independently of its anti-oxidative properties. Interestingly, maslinic acid was also found to significantly reduce lipid accumulation observed in macrophages treated with sPLA2-IIA only. Flow cytometry analysis demonstrated that the effect observed in maslinic acid might be contributed in part by suppressing sPLA2-IIA-induced endocytic activity, thereby inhibiting LDL uptake. The study further showed that maslinic acid suppresses sPLA2-IIA-induced up-regulation of PGE2 levels while having no effects on COX-2 activity. Other pro-inflammatory mediators TNF-a and IL-6 were not induced in sPLA2-IIA-treated THP-1 macrophages. The findings of this study showed that maslinic acid inhibit inflammatory effects induced by sPLA2-IIA, including foam cells formation and PGE2 production.

MeSH terms

  • Animals
  • Cardiotonic Agents / administration & dosage*
  • Foam Cells / drug effects
  • Foam Cells / pathology
  • Gene Expression Regulation / drug effects
  • Group IV Phospholipases A2 / antagonists & inhibitors
  • Group IV Phospholipases A2 / genetics*
  • Group IV Phospholipases A2 / metabolism
  • Humans
  • Inflammation / drug therapy*
  • Inflammation / genetics
  • Inflammation / pathology
  • Interleukin-6 / genetics
  • Lipoproteins, LDL / genetics
  • Macrophages / drug effects
  • Macrophages / pathology
  • Triterpenes / administration & dosage*
  • Tumor Necrosis Factor-alpha / genetics

Substances

  • Cardiotonic Agents
  • Interleukin-6
  • Lipoproteins, LDL
  • Triterpenes
  • Tumor Necrosis Factor-alpha
  • maslinic acid
  • Group IV Phospholipases A2