caa a22 4500 606175210 CHVBK 20210128100742.0 cr unu---uuuuu 210128e20151001xx s 000 0 eng 10.1007/s00018-015-1915-1 doi (NATIONALLICENCE)springer-10.1007/s00018-015-1915-1 Critical residues involved in Toll-like receptor 4 activation by cationic lipid nanocarriers are not located at the lipopolysaccharide-binding interface [Elektronische Daten] [Caroline Lonez, Kate Irvine, Malvina Pizzuto, Boris Schmidt, Nick Gay, Jean-Marie Ruysschaert, Monique Gangloff, Clare Bryant] DiC14-amidine is a cationic lipid that was originally designed as a lipid nanocarrier for nucleic acid transport, and turned out to be a Toll-like receptor 4 (TLR4) agonist as well. We found that while E. coli lipopolysaccharide (LPS) is a TLR4 agonist in all species, diC14-amidine nanoliposomes are full agonists for human, mouse and cat receptors but weak horse agonists. Taking advantage of this unusual species specificity, we used chimeric constructs based on the human and horse sequences and identified two regions in the human TLR4 that modulate the agonist activity of diC14-amidine. Interestingly, these regions lie outside the known LPS-binding domain. Competition experiments also support our hypothesis that diC14-amidine interacts primarily with TLR4 hydrophobic crevices located at the edges of the TLR4/TLR4* dimerization interface. We have characterized potential binding modes using molecular docking analysis and suggest that diC14-amidine nanoliposomes activate TLR4 by facilitating its dimerization in a process that is myeloid differentiation 2 (MD-2)-dependent and cluster of differentiation 14 (CD14)-independent. Our data suggest that TLR4 may be activated through binding at different anchoring points, expanding the repertoire of TLR4 ligands to non-MD-2-binding lipids. Springer Basel, 2015 Toll-like receptor nationallicence Cationic lipid nationallicence Nanoparticle nationallicence Activation mechanism nationallicence Species specificity nationallicence Lonez Caroline Department of Veterinary Medicine, University of Cambridge, Cambridge, UK aut Irvine Kate Department of Veterinary Medicine, University of Cambridge, Cambridge, UK aut Pizzuto Malvina Structure and Function of Biological Membranes, Université Libre de Bruxelles, Brussels, Belgium aut Schmidt Boris Structure and Function of Biological Membranes, Université Libre de Bruxelles, Brussels, Belgium aut Gay Nick Department of Biochemistry, University of Cambridge, Cambridge, UK aut Ruysschaert Jean-Marie Structure and Function of Biological Membranes, Université Libre de Bruxelles, Brussels, Belgium aut Gangloff Monique Department of Biochemistry, University of Cambridge, Cambridge, UK aut Bryant Clare Department of Veterinary Medicine, University of Cambridge, Cambridge, UK aut Cellular and Molecular Life Sciences Springer Basel 72/20(2015-10-01), 3971-3982 1420-682X 72:20<3971 2015 72 18 https://doi.org/10.1007/s00018-015-1915-1 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00018-015-1915-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lonez Caroline Department of Veterinary Medicine, University of Cambridge, Cambridge, UK aut NATIONALLICENCE 700 1- Irvine Kate Department of Veterinary Medicine, University of Cambridge, Cambridge, UK aut NATIONALLICENCE 700 1- Pizzuto Malvina Structure and Function of Biological Membranes, Université Libre de Bruxelles, Brussels, Belgium aut NATIONALLICENCE 700 1- Schmidt Boris Structure and Function of Biological Membranes, Université Libre de Bruxelles, Brussels, Belgium aut NATIONALLICENCE 700 1- Gay Nick Department of Biochemistry, University of Cambridge, Cambridge, UK aut NATIONALLICENCE 700 1- Ruysschaert Jean-Marie Structure and Function of Biological Membranes, Université Libre de Bruxelles, Brussels, Belgium aut NATIONALLICENCE 700 1- Gangloff Monique Department of Biochemistry, University of Cambridge, Cambridge, UK aut NATIONALLICENCE 700 1- Bryant Clare Department of Veterinary Medicine, University of Cambridge, Cambridge, UK aut NATIONALLICENCE 773 0- Cellular and Molecular Life Sciences Springer Basel 72/20(2015-10-01), 3971-3982 1420-682X 72:20<3971 2015 72 18