A novel whey tetrapeptide IPAV reduces interleukin-8 production induced by TNF-α in human intestinal Caco-2 cells

In the present study, an anti-inflammatory effect of enzymatic whey protein hydrolysate was examined in human intestinal Caco-2 cells. Stimulation of Caco-2 cells with tumour necrosis factor (TNF)-α induced interleukin (IL)-8 expression through the activation of nuclear factor kappa B p65, spleen tyrosine kinase and mitogen-activated protein kinases pathways. Pre-treatment of cells with whey protein hydrolysate reduced TNF-α-induced IL-8 expression. Mass spectrometry analysis has identified the active tetrapeptide IPAV, which corresponded to amino acids 94-97 of β-lactoglobulin. Pre-treatment of cells with IPAV reduced TNF-α-induced IL-8 expression and the increase in phosphorylation levels of key cellular signalling proteins. Pharmacological inhibition of peptide transporter 1 (PepT1), but not of calcium-sensing receptor, attenuated IPAV-mediated suppression of IL-8 expression. In summary, a novel anti-inflammatory tetrapeptide IPAV, derived from whey protein hydrolysate, reduced IL-8 expression induced by TNF-α. Our results suggest that IPAV, transported by PepT1, can suppress inflammatory signalling in intestinal cells.