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Doctorant(e)
Faculté des Sciences et Technologies - Nancy
Université de Lorraine
03 72 74 57 45 | rania.allouche@univ-lorraine.fr
Molecules, 29 (7), 1552.
Allouche, R., Hafeez, Z., Dary-Mourot, A., Genay, M., Miclo, L.
In addition to traditional use in fermented dairy products, S. thermophilus also exhibits anti-inflammatory properties both in live and heat-inactivated form. Recent studies have highlighted that some hydrolysates from surface proteins of S. thermophilus could be responsible partially for overall anti-inflammatory activity of this bacterium. It was hypothesized that anti-inflammatory activity could also be attributed to peptides resulting from the digestion of intracellular proteins of S. thermophilus. Therefore, total intracellular proteins (TIP) from two phenotypically different strains, LMD-9 and CNRZ-21N, were recovered by sonication followed by ammonium sulphate precipitation. The molecular masses of the TIP of both strains were very close to each other as observed by SDS-PAGE. The TIP were fractionated by size exclusion fast protein liquid chromatography to obtain a 3–10 kDa intracellular protein (IP) fraction, which was then hydrolysed with pancreatic enzyme preparation, Corolase PP. The hydrolysed IP fraction from each strain exhibited anti-inflammatory activity by modulating pro-inflammatory mediators, particularly IL-1β in LPS-stimulated THP-1 macrophages. However, a decrease in IL-8 secretion was only observed with hydrolysed IP fraction from CNRZ-21N, indicating that strain could be an important parameter in obtaining active hydrolysates. Results showed that peptides from the 3–10 kDa IP fraction of S. thermophilus could therefore be considered as postbiotics with potential beneficial effects on human health. Thus, it can be used as a promising bioactive ingredient for the development of functional foods to prevent low-grade inflammation.
Nutrients, 14 (22), pp. 4777.
Allouche, R., Genay, M., Dary-Mourot, A., Hafeez, Z., Miclo, L.
Streptococcus thermophilus, a food grade bacterium, is extensively used in the manufacture of fermented products such as yogurt and cheeses. It has been shown that S. thermophilus strains exhibited varying anti-inflammatory activities in vitro. Our previous study displayed that this activity could be partially due to peptide(s) generated by trypsin hydrolysis of the surface proteins of S. thermophilus LMD-9. Surface protease PrtS could be the source of these peptides during gastrointestinal digestion. Therefore, peptide hydrolysates were obtained by shaving two phenotypically distinct strains of S. thermophilus (LMD-9 PrtS+ and CNRZ-21N PrtS−) with pepsin, a gastric protease, followed or not by trypsinolysis. The peptide hydrolysates of both strains exhibited anti-inflammatory action through the modulation of pro-inflammatory mediators in LPS-stimulated THP-1 macrophages (COX-2, Pro-IL-1β, IL-1β, and IL-8) and LPS-stimulated HT-29 cells (IL-8). Therefore, peptides released from either PrtS+ or PrtS− strains in the gastrointestinal tract during digestion of a product containing this bacterium may display anti-inflammatory effects and reduce the risk of inflammation-related chronic diseases.
Foods, 11 (8), pp. 1157.
Allouche, R., Hafeez, Z., Papier, F., Dary-Mourot, A., Genay, M., Miclo, L.
FEBS 2023 - the 47th FEBS Congress, 08-12 juillet, Tours, France
Allouche, R., Hafeez, Z., Dary, A., Genay, M., Miclo, L.
Streptococcus thermophilus is a dairy starter granted “Generally Recognized as Safe” by the FDA and “Qualified Presumption of Safety” by EFSA. A significant part of the world's population ingests this bacterium when consuming fermented products. Some strains of S. thermophilus, either in the live or heat-inactivated state, and peptides released after shaving and hydrolysis of the surface proteins of some strains of this bacterium displayed anti-inflammatory activity in vitro (Allouche et al.,2022). S. thermophilus cells could undergo lysis during their passage through the digestive tract. Consequently, its intracellular proteins could be hydrolysed by endogenous proteases leading to the release of peptides. We hypothesized that peptides generated from digestion of intracellular protein of S. thermophilus might also contribute to its overall anti-inflammatory effect. Therefore, intracellular proteins from S. thermophilus CNRZ-21N strain were recovered after sonication. After fractionation by size exclusion chromatography, the resulting 3-10 kDa protein fraction was hydrolysed by Corolase PP, a mixture of pancreatic proteases. MS-MS analysis showed that most of the identified peptides belonged to the ribosomal proteins. The hydrolysed fraction showed anti-inflammatory activity on macrophagelike THP-1 cells inflamed by LPS since their secretion of IL-8 and IL-1β cytokines and expression level of Pro-IL-1β were reduced. The results suggest that the peptides released from a fraction of intracellular proteins of S. thermophilus after digestion by Corolase PP may contribute to the anti-inflammatory activity of this bacterium and could be used as a functional ingredient to prevent lowgrade inflammation.
5th Edition of Innovations in Food Science and Human Nutrition (IFHN-2022), 20-21 septembre, Barcelone, Espagne
Allouche, R., Hafeez, Z., Dary-Mourot, A., Genay, M., Miclo, L.
23ème Colloque du Club des Bactéries Lactiques, 08-10 juin, Rennes, France
Allouche, R., Hafeez, Z., Papier, F., Dary-Mourot, A., Genay, M., Miclo, L.
Journée doctorale virtuelle franco-allemande et transfrontalière : Biotechnologies et Sciences de la Vie, 10 novembre, dématérialisée
Allouche, R., Hafeez, Z., Dary-Mourot, A., Genay, M., Miclo, L.
Séminaire de l'École Doctorale SIReNa, 13 février, Nancy, France
Allouche, R., Hafeez, Z., Dary, A., Genay, M., Miclo, L.
Streptococcus thermophilus is widely used as a starter culture in the dairy industry and has been awarded generally recognized as safe status (GRAS) by the American Food and Drug Administration. Some strains of S. thermophilus display an anti-inflammatory activity in vitro (Junjua et al., 2016). Inflammation is a part of the regular host reaction to injury or infection caused by pathogens, damaged cells, irritants and allergens. However, the mechanism of action by which this bacterium modulates inflammatory response remains unclear. It has been shown that the hydrolysis of food proteins or endogenous proteins by some digestive proteases releases peptides with various biological activities. Such peptides can also be generated by the surface proteolytic system of Lactic Acid Bacteria (Hafeez et al., 2014) as S. thermophilus, which produces bioactive peptides from bovine caseins (Miclo et al., 2012). These peptides are inactive within the sequence of the parent protein and display their activity after a hydrolysis step. Thus, the assumption that peptides generated in the gastro-intestinal tract from hydrolysis of S. thermophilus surface or intracellular proteins could display an anti?inflammatory activity and contribute to the overall anti-inflammatory effect of the bacterium can be made. Therefore, it is interesting to explore the role of such peptides in the modulation of inflammation. In a first approach, this study aims to investigate the anti-inflammatory properties of hydrolysates genrated after hydrolysis by gastrointestinal enzymes of surface proteins of S. thermophilus. The method involves the recovery of bacterial surface polypeptides by shaving with pepsin. Supernatant obtained after shaving was analysed by RP-HPLC and showed the release of peptides. The next challenge constitutes evaluation in in vitro cell model of anti-inflammatory activity of the peptides obtained and the characterisation of these peptides by mass spectrometry. This study will lead to novel insights into the modulation of host inflammatory response through probable action of peptides obtained from S. thermophilus.
Thèse de l'Université de Lorraine soutenue le 16 novembre 2022
Allouche, R.
