ERC FUNDED PROJECTS

Plants typically release large quantities of volatiles in response to attack by herbivores or pathogens. I may claim to have contributed to various breakthroughs in this research field, including the discovery that the volatile blends induced by different attackers are astonishingly specific, resulting in characteristic, readily distinguishable odour blends. Using maize as our model plant, I wish to take several leaps forward in our understanding of this signal specificity and use this knowledge to develop sensors for the real-time detection of crop pests and diseases. For this, three interconnected work-packages will aim to: • Develop chemical analytical techniques and statistical models to decipher the odorous vocabulary of plants, and to create a complete inventory of “odour-prints” for a wide range of herbivore-plant and pathogen-plant combinations, including simultaneous infestations. • Develop and optimize nano-mechanical sensors for the detection of specific plant volatile mixtures. For this, we will initially adapt a prototype sensor that has been successfully developed for the detection of cancer-related volatiles in human breath. • Genetically manipulate maize plants to release a unique blend of root-produced volatiles upon herbivory. For this, we will engineer gene cassettes that combine recently identified P450 (CYP) genes from poplar with inducible, root-specific promoters from maize. This will result in maize plants that, in response to pest attack, release easy-to-detect aldoximes and nitriles from their roots. In short, by investigating and manipulating the specificity of inducible odour blends we will generate the necessary knowhow to develop a novel odour-detection device. The envisioned sensor technology will permit real-time monitoring of the pests and enable farmers to apply crop protection treatments at the right time and in the right place.

2 498 086 €

Start date: 2018-09-01, End date: 2023-08-31

Vaccines and immunodiagnostics have been vital for public health and medicine, however a quantitative molecular understanding of vaccine-induced antibody responses is lacking. Antibody research is currently going through a big-data driven revolution, largely due to progress in next-generation sequencing (NGS) and bioinformatic analysis of antibody repertoires. A main advantage of high-throughput antibody repertoire analysis is that it provides a wealth of quantitative information not possible with other classical methods of antibody analysis (i.e., serum titers); this information includes: clonal distribution and diversity, somatic hypermutation patterns, and lineage tracing. In preliminary work my group has established standardized methods for antibody repertoire NGS, including an experimental-bioinformatic pipeline for error and bias correction that enables highly accurate repertoire sequencing and analysis. The overall goal of this proposal will be to apply high-throughput antibody repertoire analysis for quantitative vaccine profiling and discovery of next-generation immunodiagnostics. Using mouse subunit vaccination as our model system, we will answer for the first time, a fundamental biological question within the context of antibody responses - what is the link between genotype (antibody repertoire) and phenotype (serum antibodies)? We will expand upon this approach for improved rational vaccine design by quantitatively determining the impact of a comprehensive set of subunit vaccination parameters on complete antibody landscapes. Finally, we will develop advanced bioinformatic methods to discover immunodiagnostics based on antibody repertoire sequences. In summary, this proposal lays the foundation for fundamentally new approaches in the quantitative analysis of antibody responses, which long-term will promote the development of next-generation vaccines and immunodiagnostics.

1 492 586 €

Start date: 2016-06-01, End date: 2021-05-31

Work conducted in my laboratory on the trypanosome killing factor of human serum led to the identification of the primate-specific Apolipoprotein L1 (APOL1) as a novel pore-forming protein with striking similarities with proteins of the apoptotic BCL2 family. APOL1 belongs to a family of proteins induced under inflammatory conditions in myeloid and endothelial cells. APOL1 is efficiently neutralized by the SRA protein of Trypanosoma rhodesiense, accounting for the ability of this trypanosome subspecies to infect humans and cause sleeping sickness. We found that natural APOL1 variants escaping SRA neutralization and therefore conferring human resistance to T. rhodesiense are associated with chronic kidney disease. Moreover, transgenic mice expressing these APOL1 variants exhibit an obese phenotype. Our unpublished results also indicate that APOLs control the lifespan of dendritic cells and podocytes activated by viral stimuli. Therefore, we propose that the pathology of APOL variants is due to their deregulated activity on the control of the cellular lifespan in myeloid/endothelial cells activated by pathogen detection. This project aims at characterizing (i) the molecular mechanism by which APOLs control the lifespan of activated dendritic cells and podocytes, which has direct impact on innate immunity and inflammation, and (ii) the mechanism by which APOL1 variants cause pathology. In addition, we plan to detail the physiological function of APOLs by studying the phenotype of transgenic mice either expressing human APOL1 (wild-type and variants) or devoid of APOL genes, which we have recently generated. Finally, we propose to exploit the extraordinary potential of trypanosomes for antigenic variation in order to produce SRA variants able to neutralize the pathogenic APOL1 variants. Preliminary experiments suggest that in podocytes SRA antagonizes APOL1 induction by viral stimulus and subsequent cell death, opening new perspectives to treat kidney disease.

2 250 000 €

Start date: 2015-09-01, End date: 2020-08-31

Dietary fibres are recognized for their health promoting properties; nevertheless, many of the physicochemical mechanisms behind these effects remain poorly understood. While it is understood that dietary fibres can associate with small molecules influencing, both positively or negatively their absorption, the molecular mechanism, by which these associations take place, have yet to be elucidated We propose a study of the binding in soluble dietary fibres at a molecular level to establish binding constants for various fibres and nutritionally relevant ligands. The interactions between fibres and target compounds may be quite weak, but still have a major impact on the bioavailability. To gain insight to the binding mechanisms at a level of detail that has not earlier been achieved, we will apply novel combinations of analytical techniques (MS, NMR, EPR) and both natural as well as synthetic probes to elucidate the associations in these complexes from macromolecular to atomic level. Glucans, xyloglucans and galactomannans will serve as model soluble fibres, representative of real food systems, allowing us to determine their binding constants with nutritionally relevant micronutrients, such as monosaccharides, bile acids, and metals. Furthermore, we will examine supramolecular interactions between fibre strands to evaluate possible contribution of several fibre strands to the micronutrient associations. At the atomic level, we will use complementary spectroscopies to identify the functional groups and atoms involved in the bonds between fibres and the ligands. The proposal describes a unique approach to quantify binding of small molecules by dietary fibres, which can be translated to polysaccharide interactions with ligands in a broad range of biological systems and disciplines. The findings from this study may further allow us to predictably utilize fibres in functional foods, which can have far-reaching consequences in human nutrition, and thereby also public health.

1 500 000 €

Start date: 2016-04-01, End date: 2021-03-31