Anti-inflammatory effect of procyanidin B1 on LPS-treated THP1 cells via interaction with the TLR4–MD-2 heterodimer and p38 MAPK and NF-κB signaling
- 671 Downloads
Anti-inflammatory effects of procyanidin B1 have been documented; however, the molecular mechanisms that are involved have not been fully elucidated. Molecular docking models were applied to evaluate the binding capacity of lipopolysaccharide (LPS) and procyanidin B1 with the toll-like receptor (TLR)4/myeloid differentiation factor (MD)-2 complex. LPS-induced production of the proinflammatory cytokine tumor necrosis factor (TNF)-α in a human monocyte cell line (THP1) was measured by ELISA. mRNA expression of MD-2, TLR4, TNF receptor-associated factor (TRAF)-6, and nuclear factor (NF)-κB was measured by real-time PCR with or without an 18-h co-treatment with procyanidin B1. In addition, protein expression of phosphorylated p38 mitogen-activated protein kinase (MAPK) and NF-κB was determined by Western blotting. Structural modeling studies identified Tyr296 in TLR4 and Ser120 in MD-2 as critical sites for hydrogen bonding with procyanidin B1, similar to the sites occupied by LPS. The production of TNF-α was significantly decreased by procyanidin B1 in LPS-treated THP1 cells (p < 0.05). Procyanidin B1 also significantly suppressed levels of phosphorylated p38 MAPK and NF-κB protein, as well as mRNA levels of MD-2, TRAF-6, and NF-κB (all p < 0.05). Procyanidin B1 can compete with LPS for binding to the TLR4–MD-2 heterodimer and suppress downstream activation of p38 MAPK and NF-κB signaling pathways.
KeywordsAnti-inflammatory LPS Procyanidin B1 THP1 cells TLR4–MD-2 heterodimer
This study was supported by the Young Starting Foundation of the First Affiliated Hospital, Dalian Medical University (QN2012008) and the 2013 Dalian Science and Technology Planning Project (guidance project).
Conflict of interest
The authors do not have any conflicts of interest to declare.
- 3.Serra AT, Rocha J, Sepodes B, Matias AA, Feliciano RP, de Carvalho A, Bronze MR, Duarte CM, Figueira ME (2012) Evaluation of cardiovascular protective effect of different apple varieties—correlation of response with composition. Food Chem 135:2378–2386. doi: 10.1016/j.foodchem.2012.07.067 CrossRefPubMedGoogle Scholar
- 4.Zhao J, Wang J, Chen Y, Agarwal R (1999) Anti-tumor-promoting activity of a polyphenolic fraction isolated from grape seeds in the mouse skin two-stage initiation-promotion protocol and identification of procyanidin B5-3′-gallate as the most effective antioxidant constituent. Carcinogenesis 20:1737–1745CrossRefPubMedGoogle Scholar
- 7.Terra X, Valls J, Vitrac X, Merrillon JM, Arola L, Ardevol A, Blade C, Fernandez-Larrea J, Pujadas G, Salvado J et al (2007) Grape-seed procyanidins act as antiinflammatory agents in endotoxin-stimulated RAW 264.7 macrophages by inhibiting NFkB signaling pathway. J Agric Food Chem 55:4357–4365. doi: 10.1021/jf0633185 CrossRefPubMedGoogle Scholar
- 8.Prasain JK, Peng N, Dai Y, Moore R, Arabshahi A, Wilson L, Barnes S, Michael Wyss J, Kim H, Watts RL (2009) Liquid chromatography tandem mass spectrometry identification of proanthocyanidins in rat plasma after oral administration of grape seed extract. Phytomedicine 16:233–243. doi: 10.1016/j.phymed.2008.08.006 CrossRefPubMedGoogle Scholar
- 19.Kolek MJ, Carlquist JF, Muhlestein JB, Whiting BM, Horne BD, Bair TL, Anderson JL (2004) Toll-like receptor 4 gene Asp299Gly polymorphism is associated with reductions in vascular inflammation, angiographic coronary artery disease, and clinical diabetes. Am Heart J 148:1034–1040CrossRefPubMedGoogle Scholar
- 24.Palsson-McDermott EM, Doyle SL, McGettrick AF, Hardy M, Husebye H, Banahan K, Gong M, Golenbock D, Espevik T, O’Neill LA (2009) TAG, a splice variant of the adaptor TRAM, negatively regulates the adaptor MyD88-independent TLR4 pathway. Nat Immunol 10:579–586. doi: 10.1038/ni.1727 CrossRefPubMedGoogle Scholar
- 26.Lima Mdos S, Silani Ide S, Toaldo IM, Correa LC, Biasoto AC, Pereira GE, Bordignon-Luiz MT, Ninow JL (2014) Phenolic compounds, organic acids and antioxidant activity of grape juices produced from new Brazilian varieties planted in the Northeast Region of Brazil. Food Chem 161:94–103. doi: 10.1016/j.foodchem.2014.03.109 CrossRefPubMedGoogle Scholar
- 27.Shimada T, Tokuhara D, Tsubata M, Kamiya T, Kamiya-Sameshima M, Nagamine R, Takagaki K, Sai Y, Miyamoto K, Aburada M (2012) Flavangenol (pine bark extract) and its major component procyanidin B1 enhance fatty acid oxidation in fat-loaded models. Eur J Pharmacol 677:147–153. doi: 10.1016/j.ejphar.2011.12.034 CrossRefPubMedGoogle Scholar
- 32.Chacon MR, Ceperuelo-Mallafre V, Maymo-Masip E, Mateo-Sanz JM, Arola L, Guitierrez C, Fernandez-Real JM, Ardevol A, Simon I, Vendrell J (2009) Grape-seed procyanidins modulate inflammation on human differentiated adipocytes in vitro. Cytokine 47:137–142. doi: 10.1016/j.cyto.2009.06.001 CrossRefPubMedGoogle Scholar
- 33.Gray P, Michelsen KS, Sirois CM, Lowe E, Shimada K, Crother TR, Chen S, Brikos C, Bulut Y, Latz E et al (2010) Identification of a novel human MD-2 splice variant that negatively regulates lipopolysaccharide-induced TLR4 signaling. J Immunol 184:6359–6366. doi: 10.4049/jimmunol.0903543 PubMedCentralCrossRefPubMedGoogle Scholar
- 34.Sung NY, Yang MS, Song DS, Byun EB, Kim JK, Park JH, Song BS, Lee JW, Park SH, Park HJ et al (2013) The procyanidin trimer C1 induces macrophage activation via NF-kB and MAPK pathways, leading to Th1 polarization in murine splenocytes. Eur J Pharmacol 714:218–228. doi: 10.1016/j.ejphar.2013.02.059 CrossRefPubMedGoogle Scholar