Projects / Programmes
Flagelina signaling mechanism through Tollu-like receptor 5
| Code |
Science |
Field |
Subfield |
| 3.01.00 |
Medical sciences |
Microbiology and immunology |
|
| Code |
Science |
Field |
| B500 |
Biomedical sciences |
Immunology, serology, transplantation |
| Code |
Science |
Field |
| 3.05 |
Medical and Health Sciences |
Other medical sciences |
Toll like receptor TLR5, flagellin, innate immunity, adaptive immunity, Crohn disease, cystic fibrosis
Researchers (12)
| no. |
Code |
Name and surname |
Research area |
Role |
Period |
No. of publicationsNo. of publications |
| 1. |
14360 |
PhD Mojca Benčina |
Biotechnology |
Head |
2011 - 2014 |
0 |
| 2. |
32254 |
PhD Rok Gaber |
Biotechnology |
Technical associate |
2012 - 2014 |
0 |
| 3. |
23563 |
PhD Iva Hafner Bratkovič |
Neurobiology |
Researcher |
2011 - 2014 |
0 |
| 4. |
10412 |
PhD Simon Horvat |
Biotechnical sciences |
Researcher |
2011 - 2014 |
0 |
| 5. |
28881 |
PhD Karolina Ivičak Kocjan |
Biotechnology |
Junior researcher |
2011 - 2012 |
0 |
| 6. |
06628 |
PhD Roman Jerala |
Biochemistry and molecular biology |
Researcher |
2011 - 2014 |
0 |
| 7. |
34252 |
Tina Lebar |
Biochemistry and molecular biology |
Technical associate |
2012 - 2014 |
0 |
| 8. |
21426 |
PhD Mateja Manček Keber |
Pharmacy |
Researcher |
2011 - 2013 |
0 |
| 9. |
32114 |
PhD Jerneja Mori |
Biochemistry and molecular biology |
Junior researcher |
2011 - 2013 |
0 |
| 10. |
29991 |
Alja Oblak |
Biochemistry and molecular biology |
Technical associate |
2011 - 2012 |
0 |
| 11. |
26500 |
PhD Nina Pirher |
Biotechnology |
Researcher |
2011 - 2014 |
0 |
| 12. |
32113 |
PhD Jelka Pohar |
Biotechnology |
Technical associate |
2013 |
0 |
Organisations (2)
Abstract
Activation of innate immunity via Toll-like receptors, (TLR) serves as protection against pathogens and tissue damage and is essential for activation of adaptive immunity. A Toll-like receptor 5, TLR5, expressed in virtually most types of epithelial cells of mucosal organs including gastrointestinal tract, lung or uterus, recognizes bacterial flagellin, which is the main component of bacterial flagella and a virulence factor of many Gram-positive and Gram-negative bacteria. TLR5 activation by flagellin probably leads to its dimerization, which triggers activation of the MyD88 dependent signalling pathway and synthesis of proinflammatory cytokines crucial for the defence against bacterial infections. An excessive, uncontrolled immune response accompanied with a specific genetic background could lead to an acute inflammatory response, such as in sepsis and septic shock. A significant increase of TLR5 activation and consequently synthesis of proinflammatory cytokines are characteristic for Crohn’s disease and increased susceptibility to pneumonia caused by bacterial infections such as infection with Legionella pneumophila and Pseudomonas aeruginosa that triggers chronic inflammation of lung tissue in patients with cystic fibrosis.
Structural requirements for the interaction between flagellin and TLR5 are yet to be clarified. It has already been established that both the conserved N-terminal and C-terminal helices of flagellin are required for binding and activation of TLR5. Several flagellin mutations that impair TLR5 activation have been identified, however the number and identity of binding site(s) on flagellin as well as on the TLR5 are not yet known.
Based on published results, molecular modelling and experimental results of targeted mutations, we will propose a molecular model of the receptor TLR5. We propose that binding site for flagellin on TLR5 encompasses the area in the region from 377 to 425 amino acid of the receptor TLR5 that are predicted to form a binding cleft. On the other hand residues affecting activation of TLR5 have been identified around amino acids 90 and 430 of flagellin of Salmonella typhimurium. We expect that with selected point mutations on human TLR5 receptor and the flagellin of S. typhimurium, a reliable model of flagellin anchoring and activation of the receptor will be determined. Molecular model will be supported by creation of constitutively active chimeric fusion between flagellin and TLR5, which will allow us to confirm the molecular mechanism of TLR5 activation and prepare bioactive compounds for potential immunotherapy.
Research objectives are to determine the molecular mechanism of flagellin binding to the receptor and to determine possible biochemical basis and physiological significance of the distinction among different bacterial flagellins between different organism, especially human and mice, which sensitivity to activation varies between flagellins of bacteria S. typhimurium and Serratia marcescens. We also plan to demonstrate possible existence of predefined inactive dimers of receptor and spatial and temporal cellular localization of the receptor after binding flagellin.
This knowledge will provide the possibility to engineer better peptides, agonists and antagonists, which can be used as vaccine adjuvant or for therapeutic intervention in diseases, such as: Crohn’s disease and cystic fibrosis.
Significance for science
The objectives of the research project are directed towards the study of immediate immune response in human cell lines. Immediate immunity is the first line of defence of the human body against viruses and microorganisms. Inadequate response of cells to the infection has serious consequences for human health. In contrast excessive immune response could initiate the autoimmune diseases and chronic and acute inflammations. A treatment of one problem could set in motion another. Therefore, the understanding the TLR activation as well as the mechanism of intracellular signal transduction is one of the basic problems of immunology and medicine. We addressed several questions in relation to medically important processes. We explained the key points of signaling pathways of systemic inflammatory response to bacterial infection through flagellin. Knowing the mechanism of activation is important for designing compounds for supervised activation of TLR5 as adjuvant for activation of adaptive immunity. The innovative technologies and methodologies were disseminated via presentations on conferences, publications and via student courses
Significance for the country
Education. The project team involved graduate and undergraduate students who gained the necessary skills and experience in molecular biology and immunology. The project has direct importance for society by achieving a high international level of science and education of highly qualified researchers that are important investment for development of economy. Through the exchange of researchers between foreign and domestic institutions, we ensured not only the scientific linkage between institutions, but the upgrade of research experience for graduate students and PhDs involved in the project. The development of inventive methods presents an excellent starting point for a business initiative. We filed a patent application based on results of proposed project in Slovenia and Europe. Protected innovations are now available for either licensing or start-up establishment. The proposed research also centered innovative methods and technology, which is now available for scientific community and industry. Some researchers of project team were employed by the industry; therefore, the obtained knowledge and skills were directly transferred to industry. Promotion of the science and the state. During the last years the members of project group achieved excellent success in a competition of research projects among the most eminent academic competitors and thus contributed to the promotion of natural science to the general audience as well as promotion of Slovenia as a country with good science and education. We published results in internationally well established scientific journals, which is important for relevance of the research and for the recognition of the research group and the country.
Most important scientific results
Annual report
2011,
2012,
2013,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2011,
2012,
2013,
final report,
complete report on dLib.si
