Investigating the role of the genetically modified k.lactis in the treatment of inflammatory bowel disease

Abstract

Abstract Background: Inflammatory Bowel Disease (IBD) is a major health care problem. It is characterized by chronic and relapsing inflammation of the gastrointestinal tract, causing damage to the cells. The clinical manifestations are heterogeneous and include abdominal pain, rectal bleeding, diarrhea, and weight loss. It includes two predominant clinical forms, such as Crohn’s disease and ulcerative colitis. Modern lifestyle and environmental triggers led to increasing incidence and prevalence rates among the population. In 2019, 4.5 million people were diagnosed with IBD. IBD is a multifactorial disease. Genetic predisposition, environmental factors, immune dysregulation, and microbial flora are key factors in the development of IBD. The pathophysiological mechanism of IBD involves an imbalance between pro-inflammatory and anti-inflammatory chemokines. CCL5 (C-C chemokine ligand 5) is a pro-inflammatory chemokine. It plays the pivotal role in activating multiple inflammatory pathways in IBD, such as PI3K/ATP, NF-kB and Ras/MAPK. Therefore, the CCL5-CCR5 axis is a potential therapeutic target in the treatment of IBD. Currently, existing treatment approaches often have systemic adverse effects. It is known that probiotics restore microbiota, enhance the intestinal barrier, and regulate immune response in the GIT by enhancing differentiation of regulatory T cells. Genetic modification of intestinal bacteria and yeasts are used in order to enhance the therapeutic effect. It offers a local expression of therapeutic molecules or proteins, avoiding the systemic effect on organisms. Kluyveromyces lactis (K.lactis) is an anti-inflammatory probiotic and is used in the food industry. Recent evidence suggests that wild-type K.lactis improves the symptoms in the mouse model of IBD. We developed a genetically modified K.lactis that expresses a CCR5 antagonist to reduce inflammation process. Objective: The objective of this study is to investigate the influence of genetically modified K.lactis expressing CCR5 antagonist on the inflammatory process of IBD, using MMP-10 expression as marker of intestinal inflammation in an IBD mouse model. Methods: The acute form of Crohn’s disease-like colitis in C57BL/6 mice will be induced by rectal administration of TNBS. Mice will additionally be treated by the wild-type K.lactis strain and genetically-modified strains, respectively, while the control group will receive no further treatment. The symptoms of IBD will be evaluated during the experimental period. After the sacrifice, the intestine will be isolated. MMP-10 expression will be analyzed by immunofluorescence to assess the degree of intestinal inflammation and the therapeutic effect of CCL5 antagonist. Results: it is expected that the genetically-modified K.lactis strains will reduce the inflammatory markers in mice by expressing the CCR5 antagonist. Conclusion: The use of genetically-modified probiotics provides an important opportunity to advance the treatment of IBD. The genetically-modified K.lactis serves as a potential new therapeutic approach. By locally expressing a therapeutic molecule in the intestine, such as a CCR5 antagonist, it reduces the inflammatory markers of IBD, including MMP-10 expression, and systemic adverse effects on organisms.