Lactococcus lactis Delivery of Surface Layer Protein A Protects Mice from Colitis by Re-Setting Host Immune Repertoire

Recent advances in bacteria-based platforms for inflammatory bowel diseases treatment

Inflammatory bowel disease (IBD) is a recurring chronic inflammatory disease. Current treatment strategies are aimed at alleviating clinical symptoms and are associated with gastrointestinal or systemic adverse effects. New delivery strategies are needed for the treatment of IBD. Bacteria are promising biocarriers, which can produce drugs in situ and sense the gut in real time. Herein, we focus on recent studies of engineered bacteria used for IBD treatment and introduce the application of engineered bacteria in the diagnosis. On this basis, the current dilemmas and future developments of bacterial delivery systems are discussed.

A Comprehensive Review of the Triangular Relationship among Diet-Gut Microbiota-Inflammation

The human gastrointestinal tract hosts a complex and dynamic community of microorganisms known as the gut microbiota, which play a pivotal role in numerous physiological processes, including digestion, metabolism, and immune function. Recent research has highlighted the significant impact of diet on the gut microbiota composition and functionality, and the consequential effects on host health. Concurrently, there is growing evidence linking the gut microbiota to inflammation, a key factor in many chronic diseases such as inflammatory bowel disease (IBD), obesity, diabetes, and cardiovascular diseases (CVDs). This review explores how dietary components influence the gut microbiota composition, how these microbial changes affect inflammatory pathways, and the therapeutic implications of modulating this axis for chronic inflammatory disease prevention and management. Beneficial dietary patterns, such as the Mediterranean diet (MD) and plant-based diets, promote a diverse and balanced gut microbiota composition, supporting anti-inflammatory pathways. Conversely, the Western diet (WD), high in saturated fats and refined sugars, is associated with dysbiosis and increased inflammation. With all the links between the three variables considered, this review attempts to offer a thorough examination of the triangle formed by inflammation, the gut microbiota, and food.

Display of porcine epidemic diarrhea virus spike protein B-cell linear epitope on Lactobacillus mucosae G01 S-layer surface induce a robust immunogenicity in mice

The Porcine epidemic diarrhea virus (PEDV) presents a substantial risk to the domestic pig industry, resulting in extensive and fatal viral diarrhea among piglets. Recognizing the mucosal stimulation triggered by PEDV and harnessing the regulatory impact of lactobacilli on intestinal function, we have developed a lactobacillus-based vaccine that is carefully designed to elicit a strong mucosal immune response. Through bioinformatics analysis, we examined PEDV S proteins to identify B-cell linear epitopes that meet the criteria of being non-toxic, soluble, antigenic, and capable of neutralizing the virus. In this study, a genetically modified strain of Lactobacillus mucosae G01 (L.mucosae G01) was created by utilizing the S layer protein (SLP) as a scaffold for surface presentation. Chimeric immunodominant epitopes with neutralizing activity were incorporated at various sites on SLP. The successful expression of SLP chimeric immunodominant epitope 1 on the surface of L.mucosae G01 was confirmed through indirect immunofluorescence and transmission electron microscopy, revealing the formation of a transparent membrane. The findings demonstrate that the oral administration of L.mucosae G01, which expresses the SLP chimeric immunodominant gene epitope1, induces the production of secreted IgA in the intestine and feces of mice. Additionally, there is an elevation in IgG levels in the serum. Moreover, the levels of cytokines IL-2, IL-4, IFN-γ, and IL-17 are significantly increased compared to the negative control group. These results suggest that L. mucosae G01 has the ability to deliver exogenous antigens and elicit a specific mucosal immune response against PEDV. This investigation presents new possibilities for immunoprophylaxis against PEDV-induced diarrhea.

Role of gut microbiota in infectious and inflammatory diseases

Thousands of microorganisms compose the human gut microbiota, fighting pathogens in infectious diseases and inhibiting or inducing inflammation in different immunological contexts. The gut microbiome is a dynamic and complex ecosystem that helps in the proliferation, growth, and differentiation of epithelial and immune cells to maintain intestinal homeostasis. Disorders that cause alteration of this microbiota lead to an imbalance in the host’s immune regulation. Growing evidence supports that the gut microbial community is associated with the development and progression of different infectious and inflammatory diseases. Therefore, understanding the interaction between intestinal microbiota and the modulation of the host’s immune system is fundamental to understanding the mechanisms involved in different pathologies, as well as for the search of new treatments. Here we review the main gut bacteria capable of impacting the immune response in different pathologies and we discuss the mechanisms by which this interaction between the immune system and the microbiota can alter disease outcomes.

Intestinal Engineered Probiotics as Living Therapeutics: Chassis Selection, Colonization Enhancement, Gene Circuit Design, and Biocontainment

Intestinal probiotics are often used for the in situ treatment of diseases, such as metabolic disorders, tumors, and chronic inflammatory infections. Recently, there has been an increased emphasis on intelligent, customized treatments with a focus on long-term efficacy; however, traditional probiotic therapy has not kept up with this trend. The use of synthetic biology to construct gut-engineered probiotics as live therapeutics is a promising avenue in the treatment of specific diseases, such as phenylketonuria and inflammatory bowel disease. These studies generally involve a series of fundamental design issues: choosing an engineered chassis, improving the colonization ability of engineered probiotics, designing functional gene circuits, and ensuring the safety of engineered probiotics. In this review, we summarize the relevant past research, the progress of current research, and discuss the key issues that restrict the widespread application of intestinal engineered probiotic living therapeutics.