Development of a lactic acid bacteria strain that suppresses chronic inflammation and improves glucose and lipid metabolism

Regulation of IL-10 production in dendritic cells is controlled by the co-activation of TLR2 and Mincle by Lactiplantibacillus plantarum OLL2712

We showed that Lactiplantibacillus plantarum OLL2712 (OLL2712) strongly induces interleukin (IL)-10 production in immune cells. Although beneficial effects of this strain have been observed in both mice and humans, the mechanisms underlying IL-10 induction remain unclear. In this study, we found that OLL2712 co-activates two pattern recognition receptors, leading to IL-10 production in the mouse-derived thermosensitive dendritic cell line, tsDC. We first revealed the involvement of the Toll-like receptor (TLR)2-Myeloid differentiation primary response gene (MYD) 88 pathway in OLL2712-induced IL-10 production in tsDCs. However, stimulation with the TLR2 agonist alone was insufficient to induce IL-10 production. Consequently, we explored additional signaling pathways and found that the phosphorylation of spleen tyrosine kinase (Syk) was important in response to OLL2712, which was not triggered by a TLR2 agonist alone. Notably, the activation of Syk was found to depend on macrophage-inducible C-type lectin receptor (Mincle), one of the C-type lectin receptors. However, the surface-expressed Mincle is not responsible for the IL-10 production by OLL2712. Instead, it depends on the incorporation of OLL2712 into tsDCs, suggesting that Mincle recognizes incorporated OLL2712 intracellularly. In summary, OLL2712 is initially recognized by TLR2, which subsequently induces the expression of Mincle to recognize incorporated OLL2712, ultimately inducing IL-10 production.IMPORTANCEThe objective of this study is to elucidate the mechanism by which Lactiplantibacillus plantarum OLL2712 (OLL2712), previously identified by our research group as a potent stimulator of interleukin-10 production in immune cells, exerts its immunomodulatory effects. Our findings indicate that OLL2712 acts in synergy with two pattern-recognition receptors: Toll-like receptor 2 and Macrophage inducible C-type lectin receptor (Mincle). Additionally, we observed that OLL2712 needs to be internalized intracellularly to be recognized by Mincle. These findings represent the first insights into the detailed mechanism underlying the anti-inflammatory effects of OLL2712.

Caenorhabditis elegans as a Screening Model for Probiotics with Properties against Metabolic Syndrome

There is a growing need to develop new approaches to prevent and treat diseases related to metabolic syndromes, including obesity or type 2 diabetes, that focus on the different factors involved in the pathogenesis of these diseases. Due to the role of gut microbiota in the regulation of glucose and insulin homeostasis, probiotics with beneficial properties have emerged as an alternative therapeutic tool to ameliorate metabolic diseases-related disturbances, including fat excess or inflammation. In the last few years, different strains of bacteria, mainly lactic acid bacteria (LAB) and species from the genus Bifidobacterium, have emerged as potential probiotics due to their anti-obesogenic and/or anti-diabetic properties. However, in vivo studies are needed to demonstrate the mechanisms involved in these probiotic features. In this context, Caenorhabditis elegans has emerged as a very powerful simple in vivo model to study the physiological and molecular effects of probiotics with potential applications regarding the different pathologies of metabolic syndrome. This review aims to summarize the main studies describing anti-obesogenic, anti-diabetic, or anti-inflammatory properties of probiotics using C. elegans as an in vivo research model, as well as providing a description of the molecular mechanisms involved in these activities.

Yogurt Production

Yogurt is a widely consumed dairy product that is obtained through the fermentation of lactic acid bacteria. During fermentation, these bacteria produce lactic acid, which lowers the pH and causes the coagulation of milk proteins. Metabolites of lactic acid bacteria, such as carbonyl compounds, nonvolatile or volatile acids, and exopolysaccharides, significantly affect the quality of yogurt. The production method also greatly influences yogurt characteristics. Yogurt can be produced in various forms, including solid, fluid, and soft-drinking types, depending on the manufacturing method employed. In addition, the raw materials, sterilization, homogenization, fermentation, and other conditions in each manufacturing method greatly affect yogurt's physical properties and flavor. This chapter summarizes common and modern methods of yogurt production.