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Open AccessArticle

A Dietary Mixture of Oxysterols Induces In Vitro Intestinal Inflammation through TLR2/4 Activation: The Protective Effect of Cocoa Bean Shells

1
Department of Clinical and Biological Sciences, University of Turin, 10043 Orbassano (Turin), Italy
2
Department of Agricultural, Forestry, and Food Sciences (DISAFA), 10095 Grugliasco (Turin), Italy
*
Author to whom correspondence should be addressed.
These authors contributed equally to this work.
These authors contributed to supervise manuscript as last co-authors.
Antioxidants 2019, 8(6), 151; https://doi.org/10.3390/antiox8060151
Received: 11 April 2019 / Revised: 24 May 2019 / Accepted: 25 May 2019 / Published: 31 May 2019
Background: Exaggerated Toll-like receptor (TLR)-mediated immune and inflammatory responses play a role in inflammatory bowel diseases. This report deals with the ability of a mixture of oxysterols widely present in cholesterol-rich foods to induce in vitro intestinal inflammation through TLR up-regulation. The anti-inflammatory action of four cocoa bean shell (CBS) extracts with different polyphenol content, was tested. Methods: Differentiated intestinal CaCo-2 cells were treated with a dietary oxysterol mixture (Oxy-mix) (60 µM). The expression and activation of TLR2 and TLR4, as well as the production of their downstream signaling effectors IL-8, IFNβ and TNFα were analyzed in the presence or absence of TLR antibodies. Honduras CBS extracts were characterized for their polyphenol contents; their anti-inflammatory action was analyzed in CaCo-2 cells treated with Oxy-mix. Results: Oxysterol-dependent TLR-2 and TLR4 over-expression and activation together with cytokine induction were abolished by blocking TLRs with specific antibodies. Polyphenol-rich CBS extracts consisting of high quantities of (−)-epicatechin and tannins also prevented TLR induction. Conclusions: TLR2 and TLR4 mainly contribute to inducing oxysterol-dependent intestinal inflammation. The fractionation method of CBS allowed the recovery of fractions rich in (−)-epicatechin and tannins able to counteract oxysterol-induced inflammation, thus highlighting the beneficial biological potential of specific CBS extracts. View Full-Text
Keywords: dietary oxysterols; Toll-like receptors; IL-8; IFNβ; TNFα; phenolic extract; cocoa bean shell; Honduras cocoa; (−)-epicatechin; tannins dietary oxysterols; Toll-like receptors; IL-8; IFNβ; TNFα; phenolic extract; cocoa bean shell; Honduras cocoa; (−)-epicatechin; tannins
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MDPI and ACS Style

Rossin, D.; Barbosa-Pereira, L.; Iaia, N.; Testa, G.; Sottero, B.; Poli, G.; Zeppa, G.; Biasi, F. A Dietary Mixture of Oxysterols Induces In Vitro Intestinal Inflammation through TLR2/4 Activation: The Protective Effect of Cocoa Bean Shells. Antioxidants 2019, 8, 151.

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