title: A dairy bacterium displays in vitro probiotic properties for the pharyngeal mucosa by antagonizing group A streptococci and modulating the immune response.
abstract: The probiotic approach represents an alternative strategy in the prevention and treatment of infectious diseases, not only at the intestinal level but also at other sites of the body where the microbiota plays a role in the maintenance of physiological homeostasis. In this context, we evaluated in vitro the potential abilities of probiotic and dairy bacteria in controlling Streptococcus pyogenes infections at the pharyngeal level. Initially, we analyzed bacterial adhesion to FaDu hypopharyngeal carcinoma cells and the ability to antagonize S. pyogenes on FaDu cell layers and HaCat keratinocytes. Due to its promising adhesive and antagonistic features, we studied the dairy strain Lactobacillus helveticus MIMLh5, also through in vitro immunological experiments. First, we performed quantification of several cytokines and measurement of NF-κB activation in FaDu cells. MIMLh5 efficiently reduced the induction of interleukin-6 (IL-6), IL-8, and tumor necrosis factor alpha (TNF-α), in a dose-dependent manner. After stimulation of cells with IL-1β, active NF-κB was still markedly lowered. Nevertheless, we observed an increased secretion of IL-6, gamma interferon (IFN-γ), and granulocyte-macrophage colony-stimulating factor (GM-CSF) under these conditions. These effects were associated with the ability of MIMLh5 to enhance the expression of the heat shock protein coding gene hsp70. In addition, MIMLh5 increased the GM-CSF/G-CSF ratio. This is compatible with a switch of the immune response toward a TH1 pathway, as supported by our observation that MIMLh5, once in contact with bone marrow-derived dendritic cells, triggered the secretion of TNF-α and IL-2. In conclusion, we propose MIMLh5 as a potential probiotic bacterium for the human pharynx, with promising antagonistic and immunomodulatory properties.
authors: Dipartimento di Scienze e Tecnologie Alimentari, Università degli Studi di Milano, Milano, Italy. simone.guglielmetti@unimi.it
authors: Simone
authors: S
authors: Guglielmetti
authors: Valentina
authors: V
authors: Taverniti
authors: Mario
authors: M
authors: Minuzzo
authors: Stefania
authors: S
authors: Arioli
authors: Ivan
authors: I
authors: Zanoni
authors: Milda
authors: M
authors: Stuknyte
authors: Francesca
authors: F
authors: Granucci
authors: Matti
authors: M
authors: Karp
authors: Diego
authors: D
authors: Mora
mesh_terms: D000898:Antibiosis; D001422:Bacterial Adhesion; D002460:Cell Line; D016207:Cytokines / Q000378:metabolism; D003612:Dairying; D004847:Epithelial Cells / Q000382:microbiology; D006801:Humans; D056747:Immunomodulation; D052198:Lactobacillus helveticus / Q000254:growth & development* / Q000276:immunology; D009092:Mucous Membrane / Q000382:microbiology*; D010614:Pharynx / Q000166:cytology / Q000276:immunology / Q000382:microbiology*; D019936:Probiotics; D013297:Streptococcus pyogenes / Q000254:growth & development* / Q000472:pathogenicity
chemical_list: D016207:Cytokines