Structure-function relationships of Toll-like receptors, key mediators of antiviral innate immunity, in Human Papillomavirus 16 infection and cervical cancer
Zusammenfassung der Projektergebnisse
Pattern recognition receptors (PRR), for example Toll‐like receptors (TLRs), are sensors of the innate immune system able to detect microbes based on molecular patterns, and subsequently initiate immune responses leading to the full activation of adaptive immunity. PRR play an important role in all infectious diseases but also inflammatory conditions, autoimmune diseases, metabolic diseases and cancer. Critical therefore is to understand how PRR are activated and which signaling pathways they initiate in different cells and how these are regulated. Furthermore, although an increasing number of genetic variants in genes of the PRR sensory system have been reported, little is known about their functional impact on the immune system and their association with disease. In this project we addressed two fundamental questions in the field of PRR: 1) How do PRR detect their ligands and how is signal transduction initiated? 2) Which impact do PRR SNPs have on the molecular level, immunologically and epidemiologically? Regarding the first question, we were able to find that sensors for viral or bacterial DNA (TLR9) and RNA (TLRs 7 and 8) detect ligands according to a shared principle, namely that ligand sensing involves two charged patches in their ectodomain and that ligand binding and sensing are separate events. Surprisingly, we found that different classes (RNA oligoribonucleotides vs. imidazoquinoline compounds) of ligands of TLR7/8 are discriminated at the receptor level and initiate both overlapping and distinct phosphorylation and transcription patterns. These findings are of therapeutic interest as both TLR9 (CpG DNA oligonucleotides) as well as TLR7/8 agonists (RNA oligoribonucleotides and imidazoquinoline compounds) are in clinical trials for the treatment of human disease or as vaccine adjuvants. Regarding the second research question, we have described several alleles in TLR and their signaling adaptors as functional, impacting on TLR signaling pathways and modifying cytokine production. Some alleles were found to be significantly associated with colorectal cancer survival, hepatitis C viral clearance, progression of gastritis to gastric cancer or lymphoma risk, respectively, suggesting a causative link between altered function and disease in humans that we have started to explore further. With increasingly individualized approaches in diagnostics and therapy, these findings may translate to concrete applications. For example, TLR5 variants are currently being explored as genetic biomarkers for patient stratification in screening programs for colorectal cancer, the third most frequent malignancy worldwide. In general, our work has contributed to efforts trying to making sense of the increasing number of reported genetic variants in humans with regard to the PRR sensory system. Additionally, we have started to employ functionally attenuated variants as naturally occurring functional probes to study PRR pathways further. We see such studies in the human system as an important and translationally valuable complementation to studies in murine knock‐out systems.
Projektbezogene Publikationen (Auswahl)
- Identification of an N‐terminal recognition site in TLR9 that contributes to CpG‐DNA‐mediated receptor activation. J Immunol. 2009 Jun 15;182(12):7690‐7
Peter M, Kubarenko, A, Weber AN, Dalpke, A
- A naturally occurring variant in human TLR9, P99L, is associated with loss of CpG oligonucleotide responsiveness. J Biol Chem, J Biol Chem 2010, Sept 14
Kubarenko A, Ranjan S, Rautanen, A, Mills TC, Wong S, Vannberg F, Neumaier M, Bekeredjian‐Ding I, Hill AVS, Ahmad‐Nejad P, Weber, AN
- Comprehensive Modeling and Functional Analysis of Toll‐like Receptor Ligand‐Recognition Domains. Protein Sci. 2010 Jan 13;19(3):558‐569.
Kubarenko A, Ranjan S, Colak E, George J, Frank M, Weber AN
- Mal D96N is a naturally occurring loss‐of‐function variant of TIRAP. J Immunol. 2010, Mar 15; 184(6): 3025‐32
George J, Kubarenko A, Rautanen, A, Mills TC, Colak E, Kempf T, Hill AVS, Nieters A, Weber, AN
- A point mutation in the amino terminus of TLR7 abolishes signaling without affecting ligand binding. J Immunol. 2011 Apr 1;186(7):4213‐22.
Iavarone C, Ramsauer K, Kubarenko AV, Debasitis JC, Leykin I, Weber AN, Siggs OM, Beutler B, Zhang P, Otten G, D'Oro U, Valiante NM, Mbow ML, Visintin A
- Death domain assembly in the MyD88‐IRAK4‐Myddosome is altered in two naturally occurring human MYD88 variants, S34Y and R98C. J Biol Chem 2011, Jan 14;286(2):1341‐53.
George J, Motshwene G, Wang H, Kubarenko A, Rautanen A, Mills TC, Hill AVS, Weber AN
- B lymphocytes and plasmacytoid dendritic cells from carriers of dysfunctional TLR9 alleles retain CpG‐oligonucleotide responsiveness. J Biol Chem. 2012 Jul 13;287(29):24544‐53.
Knežević J, Pavlinić D, Bendelja K, Gabrilovac J, Parcina M, Kubarenko AV, Petricevic B, Vrbanec D, Bulat‐Kardum L, Bekeredjian‐Ding I, Pavelić J, Dembić Z, Weber AN
- Neutrophils express distinct RNA receptors in a non‐canonical way. J Biol Chem. 2012 Jun 1;287(23):19409‐17.
Berger M, Hsieh CY, Bakele M, Marcos V, Rieber N, Kormann M, Mays L, Hofer L, Neth O, Vitkov L, Krautgartner WD, von Schweinitz D, Kappler R, Hector A, Weber A, Hartl D
(Siehe online unter https://doi.org/10.1074/jbc.M112.353557) - Functional TLR5 genetic variants affect human colorectal cancer survival. Cancer Res 2013;73(24):7232‐ 42.
Klimosch SN, Försti A, Eckert J, Knežević J, Bevier M, von Schönfels W, Heits N, Walter J, Hinz S, Lascorz J, Hampe J, Hartl D, Frick JS, Hemminki K, Schafmayer C, Weber AN
(Siehe online unter https://doi.org/10.1158/0008-5472.CAN-13-1746) - The Crystal Structure of Lipopolysaccharide Binding Protein Reveals the Location of a Frequent Mutation that Impairs Innate Immunity. Immunity (2013); 39(4):647 – 660
Eckert KJ, Kim YJ, Kim JI, Gürtler K, Oh D‐Y, Sur S, Lundvall L, Hamann L, van der Ploeg A, Pickkers P, Giamarellos‐Bourboulis E, Kubarenko AV, Weber AN, Kabesch M, Kumpf O, An H‐ J, Lee J‐O and Schumann RR
(Siehe online unter https://doi.org/10.1016/j.immuni.2013.09.005)
