Projects / Programmes source: ARRS

Peptides preventing response to bacterial endotoxin

Research activity

Code Science Field Subfield
1.09.00  Natural sciences and mathematics  Pharmacy   

Code Science Field
B740  Biomedical sciences  Pharmacological sciences, pharmacognosy, pharmacy, toxicology 
LPS; peptidic inhibitors of LPS; molecular recognition; Toll-like receptors; rational drug design
Evaluation (rules)
source: COBISS
Researchers (6)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  18675  Robert Bremšak    Technician  2007 - 2009  11 
2.  23940  PhD Boštjan Japelj  Natural sciences and mathematics  Junior researcher  2007  37 
3.  06628  PhD Roman Jerala  Natural sciences and mathematics  Researcher  2007 - 2009  1,141 
4.  17917  PhD Andreja Majerle  Biotechnical sciences  Researcher  2007 - 2009  92 
5.  21426  PhD Mateja Manček Keber  Natural sciences and mathematics  Researcher  2007 - 2009  152 
6.  12060  PhD Primož Pristovšek  Natural sciences and mathematics  Principal Researcher  2007 - 2009  135 
Organisations (1)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0104  National Institute of Chemistry  Ljubljana  5051592000  21,093 
The proposed project is a continuation and extension of the ongoing project Structure-based approach to neutralization of endotoxin by peptides and the EU 5th framework project ANEPID - Antimicrobial endotoxin neutralizing peptides to combat infectious diseases. Septic shock causes more than 150.000 casualties in the EU alone and indicates an extraordinary need for drugs that not only possess antimicrobial activity but also netralize the septic action of bacterial endotoxin (lipo¬poly¬saccharide, LPS). An important strategy towards prevention of sepsis is the lowering of the concentration of biologically active LPS by binding it specifically to peptides. In our lab we will develop cationic peptides using NMR and molecular modeling that are derived from lactoferrin and LBP (LPS binding protein), and other LPS binding proteins. Additionally we plan to improve peptide activity by acylation, as shown in a preliminary study with a fragment of lactoferrin. Another innovative approach towards limiting the excessive immune response to bacterial infection that we develop in our lab goes in the direction of interrupting the LPS signalling pathway by acting on the transmembrane (TM) Toll like receptor 4 (TLR4), i.e. the LPS receptor that triggers the intracellular signalling. TLR4 association is necessary for signalling. We were able to show in preliminary studies that addition of a peptide that contains the TM region of TLR4 inhibits cell activation via TLR4. In the proposed project we will study the interaction of the TM peptide in lipid environments and its structure; using mutations we will identify structural regions that are crucial for interaction with TLR4, and determine the specificity of inhibitions for the different TLRs. We will use genetically coded as well as sythetic peptides. All the equipment and know-how mecessary to complete such a complex project is available; our group is world leader in the field of structural studies of LPS neutralizing peptides. In attempts to improve the activity of peptides we will use the structures of peptides in complex with LPS and/or membrane mimetics; we will determine the former using NMR and molecular modeling techniques, and various biological activity measurements. We expect that the project will provide basis for rational design of novel peptides – inhibitors of endotoxin action.
Significance for science
New approaches to the therapy of sepsis and infections with resistant organisms are urgently needed. The possibilities of peptoids (peptidomimetics) with increased resistance to enzymatic degradation that could be effective against severe symptoms of LPS-induced septic shock are promising. The increasing structural knowledge opens pathways to design of novel bactericidal peptides that integrate into the outer membrane and inhibit the endotoxic effect of LPS. The proposed work contributes to the understanding of the mechanism of molecular signal transmission in one of the most important non-adaptive immune reaction. In the first part of the project the main impact for biophysical chemistry is improvement in understanding of peptide-LPS interaction, the development and use of methodology for hydrophibic binding in molecular modeling, and protocols for docking of amphiphillic ligands and receptors. In the second part we widened the knowledge of interactions between alpha-helices in lipid environments and of the homodimerization mechanism of TLR4 and its interaction with its TM segment. Our interdisciplinary approach with expertise in structural and cell biology represents an innovative and original contribution to the very competitive field of sepsis research. Our team is world leader in the field of structural studies of LPS-neutralizing peptides. We expect that the structural models significantly contribute to understanding of mechanisms of LPS inhibition in vitro. In the last years we have shown the importance of innate immunity receptors in chronical infections that are not linked to microorganism invasion. In this project we discovered two new types of cell signalling inhibition through Toll-like receptors where the latter bind to signal cascade proteins. Such inhibitors are instrumental in the understanding of the activation mechanism and have huge potential in development of drugs against chronical infections.
Significance for the country
Employment and increasing of knowledge is the best way of sustainable development ensuring high added value concomitant with environment protection. The interdisciplinary mode of the project enables collaboration with other research organizations within Slovenia as well as within Europe and worldwide. The results of research could contribute to health improvement which would lead to lowering of economical and socio damage because of diseases. The important part of the project is also education of students and post docs as well as presentation of results at scientific meetings. Researchers of the proposed project have presented the past results also to broad public in press, through interviews and TV emissions. The proposed research project comprises the tools of modern structural and cell biology. The research is based on seeking for new basic knowledge in the field of medicine with concomitant possibility for applicative research in industry.
Most important scientific results Annual report 2008, final report, complete report on dLib.si
Most important socioeconomically and culturally relevant results Annual report 2008, final report, complete report on dLib.si
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