Nutrition and Food Science Studies of Cholesterol Metabolism Regulation

(JSNFS Award for Excellence in Research (2015))

Abstract

We have identified, for the first time, a novel hypocholesterolemic pentapeptide (lactostatin: IIAEK) derived from bovine milk β-lactoglobulin in rats. Lactostatin activates expression of the gene for cholesterol 7α-hydroxylase (CYP7A1) , the rate-limiting enzyme for cholesterol degradation, through a new regulatory pathway involving calcium-channel-related MAPK signaling in HepG2 cells. The novel soy protein hydrolysate with bound phospholipids exerts an excellent hypocholesterolemic effect in patients with hypercholesterolemia. Soystatin (VAWWMY) , derived from soybean glycinin, is the first inhibitory peptide of intestinal cholesterol absorption in rats to have been identified. The peptide array is able to enhance the hypocholesterolemic activity of soystatin. Cattle heart protein hydrolysate or rice bran protein ameliorates hypercholesterolemia accompanied by suppression of cholesterol absorption in rats. GLWEK (ovocholestin) was identified as a CYP7A1 activated peptide derived from ovalbumin in HepG2 cells. We have identified, for the first time, a novel hypocholesterolemic protein, MRJP (Major Royal Jelly Protein) 1 in RJ or C-phycocyanin in Spirulina platensis. Our study has contributed to the development of a food for specified health use containing S-methyl-L-cysteine sulfoxide exerting a hypocholesterolemic action. Epigallocatechin gallate induces up-regulation of the LDL receptor accompanied by a reduction of atherogenic PCSK9 via the annexin A2-independent pathway.