By the use of spectroscopic techniques, foremost NMR,we determined the structure of an antimicrobial peptide based on the sequence of human lactoferrin in solution, as well as in complex with lipopolysaccharide (LPS,endotoxin) and different types of lipid environment, which are models for eukaryotic and bacterial membranes.We found that the peptide, upon binding to LPS or other lipids, folded into a defined conformation,depending on the type of their surrounding.The paper already has 10 citations.The results were presented as invited lectures at scientific conferences and universities abroad.
COBISS.SI-ID: 3635994
TLR3 receptor recognizes double stranded RNA. It is activated only through binding of dsRNA longer than 21 base pairs. We have discovered the existence of additional RNA binding site at N-terminus. We showed that siRNA comprising 21 bp represents minimal size of RNA duplex that can bind to both binding sites of TLR3 ectodomain and causes nonspecific, sequence independent immune response by interferon production. We showed that the secondary structure of nucleic acids affects TLR3 activation, which is important for the design of good therapeutic interfering RNA.
COBISS.SI-ID: 3954714
Bacterial lipopolysaccharide (LPS, endotoxin) is recognized by innate immune system through MD-2/TLR4 receptor complex. Murine but not human cells expressing MD-2/TLR4 are also activated by paclitaxel, which is used as a mitotic inhibitor in cancer therapy. We showed that paclitaxel binds to human MD-2 and that the binding site of paclitaxel overlaps with the binding site of LPS. This results in inhibition of LPS signaling. Therefore paclitaxel and his analogues could be used as a lead to therapeutic inhibitors of processes that engage MD-2, such as sepsis or other inflammatory diseases.
COBISS.SI-ID: 4065818
We have proposed a model of activation of receptor complex TLR4/MD-2 by endotoxin (LPS): Hydrophobic residues at positions 82, 85 and 87 of MD-2 are essential both for transfer of LPS from CD14 to monomeric MD-2 and for TLR4 activation. Phe-440 and Phe-463, conserved hydrophobic residues of the TLR4 ectodomain, are essential for activation of TLR4 by LPS. Val-82, Met-85 and Leu-87 in MD-2 and distal portions of a secondary acyl chain of hexaacylated lipid A form a hydrophobic surface that interacts with Phe-440 and Phe-463 on a neighboring TLR4/MD-2/LPS complex, driving TLR4 activation.
COBISS.SI-ID: 4120602
MD-2 is a part of the TLR4 signaling complex with indispensable role in activation of the LPS signaling pathway and thus a suitable target for the therapeutic inhibition of TLR4 signaling. Compounds with affinity for the hydrophobic pocket in MD-2 were tested. IAANS and N-pyrene maleimide formed covalent bond with MD-2 through Cys133 and inhibited LPS signaling. Cell activation was inhibited by JTT-705 originally targeted against cholesterol-ester transfer protein and antirheumatic compound auranofin. Oral intake of JTT-705 significantly inhibited LPS-triggered TNFa production in mice.
COBISS.SI-ID: 4173082