In vertebrates, a receptor-based, innate sensing machinery is used to detect the presence of microbederived molecules or the perturbation microbial infection causes within the host. In the context of viral infection, non-self nucleic acids are sensed by a set of intracellular receptors that upon activation initiate broad antiviral effector responses to eliminate the imminent threat. Over the past years our understanding of these processes has considerably grown, mainly by employing murine knockout models. Recent advances in genome engineering now provide the opportunity to knockout genes or even to perform functional genetic screens in human cells, providing a powerful means to validate and generate hypotheses. We have developed a high-throughput genome targeting and validation platform that allows us to tackle large-scale loss-of-function studies both at a polyclonal as well as an arrayed format. In addition, we have invested considerable efforts to render this technology applicable to study innate immune sensing and signalling pathways in the human system. GENESIS will combine these efforts to tackle pertinent questions in this field that could not have been addressed before: We will systematically dissect known nucleic acid sensing pathways in the human system to explore their unique roles, cooperativity or redundancy in detecting non-self nucleic acids. We will perform polyclonal, genome-wide loss-of-function screens to elucidate signalling events downstream of intracellular DNA and RNA sensing pathways and their roles in orchestrating antiviral effector mechanisms. Moreover, in a large-scale perturbation study, we will specifically address the role of the kinome in antiviral innate immune signalling pathways, exploring the role of its individual members and their epistatic relationships in orchestrating gene expression. Altogether, these studies will allow us to obtain insight into innate immune signalling pathways at unprecedented precision, depth and breadth.

Neurodegeneration is a major health concern affecting millions of individuals in Europe, with this number constantly increasing as population ages. A cure for this spectrum of conditions is still missing, in part due to differences between available experimental models and human pathophysiology. My aim is to develop an in vitro 3D brain tissue model that combine the major brain cell types (obtained from human induced pluripotent stem cells - iPSCs) also including vascular cells, for better resembling the human brain. Currently, the available in vitro 3D brain tissue models lack a functional vasculature with brain-specific features, thus limiting the possibility to study (vascular-related) pathophysiology. Transplantation is still the only strategy leading to an extensive and functional vascularization of 3D brain models. I will combine -omics technologies for optimizing the vascularization of 3D brain tissue models. First, I will investigate whether factors released by iPSC-derived neurons and their precursor cells can promote vessel formation by the endothelium. Second, I will determine which changes occur in 3D brain tissue models upon transplantation compared with in vitro culture. I will then reproduce the identified drivers of this process for obtaining a fully in vitro vascularized 3D brain tissue model, without the need for transplantation. Finally, I will show that the manipulation of this vascularized 3D models allows for studying the vascular contribution to mechanisms of neurodegeneration and for evaluating possible intervention strategies. The optimization of in vitro vascularized 3D brain tissue models will facilitate reducing costs and number of experimental animals. Also, their ease of manipulation and high-throughput will facilitate mechanism investigation and drug screening. Altogether, the MSCA fellowship will allow me to work on a relevant project while building critical skills for continuing my career as an independent researcher.