Transport of cowpea bean derived peptides and their modulator effects on mRNA expression of cholesterol-related genes in Caco-2 and HepG2 cells

This work studied the cell transport of peptidase-generated peptides from cowpea bean proteins and their effects on mRNA expression of cholesterol-related genes in intestinal and liver cells. The ≤3 kDa hydrolysate was obtained and incubated with Caco-2 intestinal cells using Transwell® plates. HepG2 liver cells were incubated with synthetic analogues of peptides (MELNAVSVVHS and MELNAVSVVSH) identified by “de novo” peptide sequencing in the Caco-2 monolayer permeates. The mRNA expression of NPC1L1, ABCA1 and ABCG1 was measured in Caco-2 cells, in the presence or absence of ≤3 kDa hydrolysate and the expression of HMGCR, SREBP2, LXRα, AMPK1, was determined in the HepG2 cells in the presence or absence of synthetic peptides. Exposure of Caco-2 cells to cowpea ≤3 kDa hydrolysate (2.5 and 5 mg/mL) increased ABCG1 expression at 6 h and 12 h. SREBP2, HMGCR and LDLR mRNA levels were reduced in HepG2 cells after 24 h of treatment with MELNAVSVVHS peptide (50 μM and 100 μM). These results suggest that MELNAVSVVHS peptide is able to cross intestinal barrier and to modulate genes involved in cholesterol homeostasis.