Procyanidin A2, a polyphenolic compound, exerts anti-inflammatory and anti-oxidative activity in lipopolysaccharide-stimulated RAW264.7 cells

PLoS One. 2020 Aug 5;15(8):e0237017. doi: 10.1371/journal.pone.0237017. eCollection 2020.

Abstract

Procyandin A2 (PCA2) is a polyphenolic compound which is isolated from grape seeds. It has been reported that PCA2 exhibits antioxidative and anti-inflammatory effects, but its molecular mechanism is still poorly understood. This study tests the hypothesis that PCA2 suppresses lipopolysaccharide (LPS)-induced inflammation and oxidative stress through targeting the nuclear factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), and NF-E2-related factor 2 (Nrf2) pathways in RAW264.7 cells. PCA2 (20, 40, 80 μM) exhibited no significant cytotoxicity in RAW264.7 cells and showed an inhibitory effect on an LPS-induced nitrite level. Pro-inflammatory cytokines like tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), prostaglandin E2 (PGE2), nitric oxide (NO), and reactive oxygen species (ROS) were suppressed by PCA2 with a concentration range of 0-80 μM. The mRNA levels of TNF-α and IL-6 were inhibited by PCA2 (80 μM). The hallmark-protein expression of the NF-κB (p-IKKα/β, p-IκBα, and p-p65) and MAPK (p-p38, p-JNK, and p-ERK) pathways were decreased by PCA2 in LPS-stimulated RAW264.7 cells. In addition, immunofluorescence results indicated that PCA2 (80 μM) promoted the translocation of NF-κB/p65 from the cytoplasm into the nucleus. PCA2 upregulated the expressions of Nrf2 and HO-1 and downregulated the expression of Keap-1. Simultaneously, PCA2 (80 μM) reversed LPS-induced Nrf2 translocation from the nucleus into the cytoplasm. Collectively, PCA2 protect cells against the damage from inflammation and oxidative injury, which suggest a potential therapeutic strategy for inflammatory and oxidative stress through targeting NF-κB, MAPK, and Nrf2 pathways in RAW264.7 cells.

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / pharmacology
  • Antioxidants / pharmacology
  • Catechin / metabolism*
  • Catechin / pharmacology*
  • Cytokines / metabolism
  • Dinoprostone / metabolism
  • Heme Oxygenase-1 / metabolism
  • Inflammation / drug therapy*
  • Lipopolysaccharides / pharmacology
  • MAP Kinase Signaling System / drug effects
  • Mice
  • Mitogen-Activated Protein Kinase 1 / drug effects
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinases / metabolism
  • NF-E2-Related Factor 2 / drug effects
  • NF-E2-Related Factor 2 / metabolism
  • NF-KappaB Inhibitor alpha / metabolism
  • NF-kappa B / drug effects
  • NF-kappa B / metabolism
  • Nitric Oxide / metabolism
  • Proanthocyanidins / metabolism*
  • Proanthocyanidins / pharmacology*
  • RAW 264.7 Cells
  • Signal Transduction / drug effects

Substances

  • Anti-Inflammatory Agents
  • Antioxidants
  • Cytokines
  • Lipopolysaccharides
  • NF-E2-Related Factor 2
  • NF-kappa B
  • Proanthocyanidins
  • procyanidin A2
  • NF-KappaB Inhibitor alpha
  • Nitric Oxide
  • Catechin
  • Heme Oxygenase-1
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinases
  • Dinoprostone

Grants and funding

The author(s) received no specific funding for this work.