Soya protein hydrolysates modify the expression of various pro-inflammatory genes induced by fatty acids in ovine phagocytes

Green Alga Ulva spp. Hydrolysates and Their Peptide Fractions Regulate Cytokine Production in Splenic Macrophages and Lymphocytes Involving the TLR4-NFκB/MAPK Pathways

Hydrolysates of food protein sources have immunomodulatory effects, which are of interest for use as functional foods. In this study, we have characterized the immune regulatory effect on rat splenocytes, macrophages and T lymphocytes of Ulva spp. hydrolysates and their peptide fractions with or without in vitro gastrointestinal digestion and/or ultrafiltration. IL-10 was induced in almost all conditions and cell types obtained from wild type animals. The induction was in general increased by ultrafiltration and in vitro gastrointestinal digestion. TNF was also induced in basal conditions. In turn, TNF and IFN-γ production was attenuated by the hydrolysate products in lipopolysaccharide or concanavalin A immune stimulated cells. Inhibitors for the activation of NFκB, MAPK p38 and JNK inhibited IL-10 induction in rat splenocytes. The response was dramatically attenuated in TLR4-/- cells, and only modestly in TLR2-/- cells. Food peptides from Ulva spp. genus exert anti-inflammatory effects in immune cells mediated by TLR4 and NFκB. Similarity with the immunomodulatory profile of protein hydrolysates from other sources suggests a common mechanism.

Leucocyte expression of genes implicated in the plasminogen activation cascade is modulated by yoghurt peptides

The urokinase-plasminogen activator (u-PA), its receptor (u-PAR) and the inhibitors of u-PA (PAI-1 and PAI-2) provide a multi-molecular system in leucocytes that exerts pleiotropic functions influencing the development of inflammatory and immune responses. The objective of the present study was to examine the ability of water soluble extracts (WSE) obtained from traditional Greek yoghurt made from bovine or ovine milk to modulate the expression of u-PA, u-PAR, PAI-1 and PAI-2 in ovine monocytes and neutrophils. WSE were obtained from 8 commercial traditional type Greek yoghurts made from ovine or bovine milk. WSE upregulated the expression of all 4 u-PA related genes in monocytes but the upregulation was much higher in the PAI-1 (10-fold) than in u-PA and u-PAR (3–4 fold) thus, shifting the system towards inhibition. In line with this observation, WSE reduced total and membrane-bound u-PA activity in monocytes. In neutrophils, WSE caused small (50–60%) but significant (P < 0·05) reductions in expression of u-PAR and PAI-2 but had no effect on expression of u-PA, PAI-1 and on total cell-associated and membrane-bound u-PA activity. WSE from yoghurts made from bovine or ovine milk were essentially equally effective in affecting the u-PA system except for the u-PAR gene in ovine neutrophils that was affected (reduced) by the ovine and not the bovine WSE. In conclusion, peptides present in WSE modulated the expression of u-PA related genes but the effect was much more prominent in monocytes than in neutrophils.