Quercetin Attenuates Adhesion Molecule Expression in Intestinal Microvascular Endothelial Cells by Modulating...

Area of Science:

• Endocrinology
• Immunology
• Pharmacology

Background:

• Inflammatory bowel disease (IBD) involves microvascular endothelial cell activation and immune cell adhesion.
• Quercetin, a dietary flavone, is investigated for its anti-inflammatory properties.

Purpose of the Study:

• To evaluate the effects of quercetin on lipopolysaccharide (LPS)-induced inflammation in rat intestinal microvascular endothelial cells (RIMVECs).
• To elucidate the underlying molecular mechanisms of quercetin's action in RIMVECs.

Main Methods:

• RIMVECs were treated with varying concentrations of quercetin followed by LPS stimulation.
• ELISA and Western blot assays were employed to measure protein levels of adhesion molecules (ICAM-1, VCAM-1) and key signaling proteins (TLR4, NF-κB, IκB-α, ERK, JNK, STAT, MAPK p38).

Main Results:

• Quercetin significantly reduced LPS-induced ICAM-1 and VCAM-1 protein levels.
• Quercetin inhibited Toll-like receptor 4 (TLR4) expression, NF-κB p65, ERK, JNK, and STAT phosphorylation, while decreasing IκB-α degradation.
• The p38 MAPK signaling pathway was not implicated in quercetin's anti-inflammatory effects.

Conclusions:

• Quercetin exhibits anti-inflammatory effects in RIMVECs by suppressing ICAM-1 and VCAM-1 expression.
• The mechanism involves the inhibition of TLR4, NF-κB, ERK, JNK, and STAT signaling pathways.
• The p38 signaling pathway does not contribute to quercetin's observed anti-inflammatory actions.