Human Microbiota and Host-Interactions

A.Y. 2023/2024
6
Max ECTS
56
Overall hours
SSD
BIO/19
Language
Italian
Learning objectives
The teaching aims to provide a deep knowledge of the microbiota functions, both from the microbiological point of view (bacterial composition and function) and from an immunological perspective (protective role of the microbiota and microbiota-host interaction). The teaching has the objective to broaden and consolidate the knowledge related to:
- role and composition of the main bacterial components of the human microbiota, in particular of the gastro-intestinal tract;
- differences between commensal and pathogenic bacteria in terms of virulence factors and interaction with immune system, with particular reference to foodborne diseases;
- dysbiosis definition and characterization by omics-technologies, and the use of probiotics as therapeutic approach to manipulate dysbiosis.
The learning objectives of the practical laboratory activities are to acquire basic cellular microbiology techniques related to the study of host-bacteria interaction, in order to understand the different interactions between pathogen or commensal bacteria and host immune system, and to acquire the ability to critically analyze the results obtained.
Expected learning outcomes
By the end of the course, students will be able to define the differences between commensal bacteria and pathogens, to understand the mechanisms of bacterial pathogenicity and interaction with the immune system. Students will be able to define the human microbiota in terms of composition and function, and describe in depth the different mechanisms of host-microorganism interaction underlying the innate and adaptive immune system. Students will acquire detailed knowledge and understanding of the gut-microbiota dysbiosis and dysbiosis-driven disease processes.

Through the practical laboratory activities students will be able to use basic methods of cellular microbiology and to apply the cultural skills acquired on the host-microorganism interaction mechanisms. By discussing the results obtained during practical laboratory activities students will develop analytical and scientific communication skills.
Single course

This course can be attended as a single course.

Course syllabus and organization

Single session

Responsible
Lesson period
Second semester
Course syllabus
Microorganisms: taxonomy, fundamental and ancillary bacterial structures, virulence factors and pathogenicity. Role and relevance of microorganisms in foods. Foodborne diseases: virulence factors and pathogenic mechanisms, bacterial toxins, adherence and invasion mechanisms.
Innate immunity: physical and chemical barriers. Role and functions of epithelial cells and antimicrobial peptides. Macrophages and neutrophils: role and function in host defence, mechanism of phagocytosis and NETs formation. Role of dendritic cells and the complement system in host defence. Bacterial evasion strategies from components of the innate immune system.
Adaptive immunity: antigen-presenting cells, difference between MHC-I and MHC-II. Mechanism of antigen-presentation and recognition in bacterial infections. Immunoevasion strategies adopted by pathogens to elude antigen-presentation.
T lymphocytes: activation and effector functions of T cells in response to commensal bacteria and pathogens. Antigen-specificity of T-cells and mechanisms used by pathogenic bacteria to avoid adaptive immunity.
Microbiota: composition, phyla and enterotypes. Gut Microbiota: microbial-microbial and host-microbial interactions. "OMICS"-technologies to study human microbiota: metagenomics and metatranscriptomics. Bioinformatic analysis: 16S analysis, database example. Dysbiosis: microbiota alterations in human diseases and immune evasion strategies of pathogenic microorganisms. Analysis and characterization of gut microbiota in the pathogenesis of different chronic inflammatory intestinal diseases: irritable bowel syndrome (IBS) and Inflammatory bowel disease (IBD).
Probiotics, prebiotics, postbiotics, genetically engineered probiotics and Fecal-microbiota Transplantation: immuno-modulatory effects and possible clinical application in Dysbiosis-associated diseases.
Gut-Brain axis and Gut-lung axis: mechanism of bidirectional communication between microbiota and the central/enteric nervous system, and lung microbiota and chronic lung inflammation. Intestinal microbiome alteration and its relationship to neurodegenerative diseases (Multiple Sclerosis and Parkinson's). Dysbiosis in Lung microbiota and its relationship to chronic inflammatory airway diseases (Asthma, Cystic Fibrosis, COPD).
Practical laboratory activities: infection of an epithelial cell line with commensal or pathobionts bacteria and analysis of their adhesion and invasion capability. Evaluation of bacterial isolates from different samples (yogurt, probiotic formulation): aerobic and anaerobic growth, quantification of probiotic isolates. Evaluation of the inflammatory response of epithelial cells after infection with probiotic or pathobionts bacteria.
Prerequisites for admission
Basic knowledge of microbiology is required.
Teaching methods
The educational activities include classroom teaching (5 ECTS), supported by PowerPoint presentations, and practical laboratory activities. Attendance of all planned activities is strongly recommended. The students are invited to actively participate in the discussion both to improve their critical skills, and to re-elaborate the concepts acquired during the lessons. During practical laboratory activities (1 ECTS) the students will actively take part in the experiments of host-pathogen interaction, in which some of the key concepts acquired during the lectures will be applied.
The teaching material will be made available to the students on the ARIEL website.
Teaching Resources
The following books may be used as reference texts:
- Principi di microbiologia medica (Antonelli - Clementi - Pozzi - Rossolini)
- Biologia dei microrganismi (Dehò-Galli)
Also, all the PDF presentations will be made available, together with scientific papers, as an aid to the student.
Assessment methods and Criteria
The acquisition of knowledge and the achievement of the expected learning outcomes are verified through a written examination (7 open-ended questions, duration of 90 minutes). The test aims to evaluate, by open-ended questions, both the acquired knowledge of cellular microbiology, in particular on the mechanisms of bacterial virulence and pathogenesis, and the understanding of the mechanisms of interaction between pathogens, commensal microbiota and host immune system. The final assessment will also take into account the ability to discuss and comment with the correct scientific language. The final grade is expressed out of 30, with a passing mark of 18/30. The examination procedures are the same for attending and non-attending students. The exam results will be communicated by e-mail.
BIO/19 - MICROBIOLOGY - University credits: 6
Practicals: 16 hours
Lessons: 40 hours
Professor: Paroni Moira
Professor(s)
Reception:
10am-12pm (by email appointment)
Department of Biosciences (Scientific Buildings) - 1st floor Tower B