Publications

2022

• ACL - Articles comité de lecture référencés bases de données AERES

  Cell proteins obtained by peptic shaving of two phenotypically different strains of Streptococcus thermophilus as a source of anti-inflammatory peptides

  Nutrients, 14 (22), pp. 4777.

  Allouche, R., Genay, M., Dary-Mourot, A., Hafeez, Z., Miclo, L.

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  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.

• ACL - Articles comité de lecture référencés bases de données AERES

  In vitro anti-inflammatory activity of peptides obtained by tryptic shaving of surface proteins of Streptococcus thermophilus LMD-9

  Foods, 11 (8), pp. 1157.

  Allouche, R., Hafeez, Z., Papier, F., Dary-Mourot, A., Genay, M., Miclo, L.

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  Streptococcus thermophilus, a lactic acid bacterium widely used in the dairy industry, is consumed regularly by a significant proportion of the population. Some strains show in vitro anti-inflammatory activity which is not fully understood. We hypothesized that peptides released from the surface proteins of this bacterium during digestion could be implied in this activity. Consequently, we prepared a peptide hydrolysate by shaving and hydrolysis of surface proteins using trypsin, and the origin of peptides was checked by liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis. Most of the identified peptides originated from bacterial cell surface proteins. The anti-inflammatory activity of peptide hydrolysate was investigated under inflammatory conditions in two cell models. Peptide hydrolysate significantly decreased secretion of pro-inflammatory cytokine IL-8 in lipopolysaccharide (LPS)-stimulated human colon epithelial HT-29 cells. It also reduced the production of pro-inflammatory cytokines IL-8, IL-1? and the protein expression levels of Pro-IL-1? and COX-2 in LPS-stimulated THP-1 macrophages. The results showed that peptides released from bacterial surface proteins by a pancreatic protease could therefore participate in an anti-inflammatory activity of S. thermophilus LMD-9 and could prevent low-grade inflammation

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Communications

2023

• C-AFF - Communications par affiche dans un congrès international ou national

  Peptides obtained after in vitro digestion of intracellular proteins of S. thermophilus display anti-inflammatory activity in THP-1 cells

  FEBS 2023 - the 47th FEBS Congress, 08-12 juillet, Tours, France

  Allouche, R., Hafeez, Z., Dary, A., Genay, M., Miclo, L.

  See the abstract

  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.

2022

• C-ACTI - Communications avec actes dans un congrès international

  Streptococcus thermophilus: anti-inflammatory potential of surface protein derived-peptides

  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.
• C-COM - Communications orales sans actes dans un congrès international ou national

  Are peptides released from surface proteins of S. thermophilus contributing to its anti-inflammatory activity in vitro?

  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.

  See the abstract

  Inflammation provides protection against injury, trauma or infection caused by damaged cells, irritants, or pathogens. This process eliminates injurious agents or intruders and clear components of damaged tissues. Nevertheless, low grade chronic inflammation is often associated with various pathologies. Attention is paid on bioactive peptides released from food proteins that could modulate inflammatory key factors and consequently delay the onset of these chronic diseases. Moreover, LAB, components of fermented dairy products, have also been reported to display anti-inflammatory properties both in in vitro and in vivo studies. Among LAB, Streptococcus thermophilus is widely used as a starter culture in the dairy industry. It is largely and regularly consumed by a significant proportion of the population in fermented milk products. Studies revealed that some strains of S. thermophilus displayed an anti-inflammatory activity in vitro but the mechanism is unknown. Thus, the assumption that peptides generated in the gastro-intestinal tract from hydrolysis of S. thermophilus surface proteins could display an anti-inflammatory activity and contribute to the overall anti-inflammatory effect of the bacterium can be made. After proteolytic “shaving” of S. thermophilus cells with digestive enzymes and subsequent mass spectrometry analysis, it was found that the majority of the identified peptides belongs to the surface-located proteins of this bacterium. The total set of peptides from surface proteins showed an anti-inflammatory activity since secretion of IL-8 and IL-1? cytokines by in macrophage-like THP-1 cells was reduced after LPS-induced inflammation. The results suggest that the peptides from surface proteins of S. thermophilus may contribute to the potential anti-inflammatory action of this bacterium.

2020

• C-COM - Communications orales sans actes dans un congrès international ou national

  Les peptides libérés à partir de protéines de surface de S. thermophilus sont-ils responsables de son activité anti-inflammatoire in vitro ?

  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.

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• C-ED/RES - Communication de type ED ou diffusion restreinte

  Peptides from proteins of Streptococcus thermophilus: an actor of its anti inflammatory properties?

  Séminaire de l'École Doctorale SIReNa, 13 février, Nancy, France

  Allouche, R., Hafeez, Z., Dary, A., Genay, M., Miclo, L.

  See the abstract

  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.

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Masters - Thèses - HDR

2022

• Thèses

  Effet anti-inflammatoire d'hydrolysats de protéines de surface ou intracellulaires de Streptococcus thermophilus obtenus après action de protéases digestives

  Thèse de l'Université de Lorraine soutenue le 16 novembre 2022

  Allouche, R.

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