Blood stages of the protozoan parasite Plasmodium falciparum are responsible for malaria, a disease that kills more than 400'000 people annually. During its development in red blood cells the parasite internalises a large part of the host cell cytosol (hemoglobin) in an endocytic process and digests it in its food vacuole. We recently identified a critical connection of this hemoglobin endocytosis with resistance of the parasite to the current frontline drug Artemisinin, revealing the mechanism of resistance. Artemisinin is activated by hemoglobin degradation products and we found that Artemisinin resistant parasite endocytose less. Using a toolbox of recently established approaches to carry out functional studies in malaria parasites, we identified an entire series of proteins involved in endocytosis that are involved in resistance to Artemisinin. This included Kelch13, the molecular marker of Artemisinin resistance in field samples. This provides us with a unique opportunity (i) to elucidate how these molecules orchestrate endocytosis, a prominent essential process in these parasites that so far is not understood on a molecular level, (ii) to specifically understand the role of Kelch13 in this process and in resistance, and (iii) to elucidate the reason for the fitness cost that is associated with Artemisinin resistance and the compensatory mechanisms the parasite uses to mitigate them. We expect this research program to not only elucidate so far elusive key aspects of the cell biology of this important parasite, but also to identify critical constraints of Artemisinin resistant parasites and possible ways to circumvent ART resistance.

Ebolaviruses comprise five virus species of which at least three are highly pathogenic for humans. Other mammalian species such as non-human primates, forest antelopes and pigs are susceptible to ebolavirus infection with different degree of severity. However, bats and laboratory mice are entirely resistant to ebolaviruses. Why do ebolaviruses cause severe disease in some species but not others? This question, which is paramount to understand ebolavirus pathogenesis is the central question of our proposal. To address it, we will build on technology developed by the host laboratory to develop xenochimeric mice, that is, severely immunodeficient mice whose hematopoietic system has been replaced with another from a donor species (e. g. bats, monkeys or humans). This novel in vivo system will allow us to investigate the kinetics of ebolavirus infection across species and to dissect the mechanisms responsible for pathogenicity.

Intracellular parasitism is a major hallmark of the most successful and deadly human pathogens. This microbial survival strategy is especially devastating if immune cells are exploited as hosts. Here we propose to use the protozoan parasite Leishmania (L.) donovani as model system to investigate the impact of pathogen-derived signalling molecules on parasite viability, virulence, and host cell expression profile. L. donovani is the causative agent of visceral leishmaniasis that represents a major public health problem worldwide and has been declared as the most significant emerging parasitic disease in Europe due to global warming. Despite the relevance of intracellular Leishmania infection in global mortality and morbidity, surprisingly little is known on how these microbes reprogram their host cell to establish permissive conditions for survival. The TranSig consortium is focused on secreted Leishmania signalling proteins that may act in “trans” to modulate the host cell phenotype. Our project emerges from a series of previously published observations showing (i) inactivation of macrophage immune signalling and anti-microbial activities by intracellular Leishmania, (ii) release of the parasite casein kinase homolog CK1.2 and the chaperone HSP90 into the host cell cytoplasm, and (iii) direct interaction of CK1.2 with host immune proteins. We hypothesize that CK1.2 is released through exosomes into the host cell cytoplasm in a HSP90-dependent manner, where it modulates signalling by phosphorylation of host proteins in order to establish permissive conditions for intracellular parasite survival. TranSig investigates this innovative working hypothesis through three complementary and multi-disciplinary tasks by applying genetic and microscopic approaches to gain insight into the function and localization of the Leishmania ecto-kinase CK1.2 (Task 1), by using a chemical-genetics approach to functionally analyse the role of HSP90 phoshorylation on chaperone function and localization (Task 2), and by investigating the regulatory relationship between CK1.2 and Hsp90 and their interaction partners, and the impact of both kinase and chaperone activities on the host cell phenotype by transcript profiling using RNAseq technology (Task 3). Our ultimate goal is to translate our research findings into novel potent anti-leishmanial therapies by interfering with parasite protein release thus restoring the host cell anti-microbial potential. The TranSig consortium mobilizes and synergizes two world-renowned centers in infectious diseases and parasitology, the Institut Pasteur in France (Partner 1) and the Bernhard Nocht Institute for Tropical Medicine in Germany (Partner 2). Significantly, both partners have a common interest in Leishmania stress signaling, with the German partner being an expert in parasite heat shock protein and chaperone biology, and the French partner providing expertise in parasite kinase biology and stress-induced protein phosphorylation. This complementary interest and expertise in parasite stress response is documented through a recent joint high-impact publication in PNAS. TranSig thus provides a unique opportunity to (for the first time) financially support this validated collaboration and to establish a powerful platform driving scientific excellence across European borders. TranSig will deliver considerable progress beyond the state-of-the-art with respect to (i) our very limited knowledge in the fields of parasite protein kinase and heat shock protein biology, and Leishmania-host cell interaction, with relevance to other intracellular parasites, such as Trypanosoma cruzi and Plasmodium falciparum, and (ii) the identification of novel drug targets that directly feed into the drug development pipeline established by Partner 1 through the LEISHDRUG (www.leishdrug.org) and TRANSLEISH (www.transleish.org) consortia.

The first Ebolavirus Zaire (EBOV) outbreak of 2014 was declared on 22 March in Guinea. As of 30 September 2014, the World Health Organization (WHO) reports the total number of cases in the current outbreak of Ebola virus disease (EVD) in West Africa at 7470, with 3431 deaths. The US Centers for Disease Control and Prevention states that the number of cases is currently doubling every 20 days and estimates the true number of cases at 2.5 times higher than that reported. Countries that have been affected are Guinea, Liberia, Nigeria, Senegal and Sierra Leone. Ten percent of fatalities have occurred among front line health care workers attempting to contain the epidemic. On 7 August 2014, the WHO requested that GSK “fully engage in WHO-coordinated efforts to test, license and make available safe and effective Ebola interventions” to assist in the control of the outbreak. Taking into account the early stage of development, EbolaVac seeks to accelerate the clinical development of the GSK chimpanzee adenovirus type 3 Ebolavirus Zaire (ChAd3-EBO Z) vaccine candidate to make the vaccine available to frontline health care workers at risk and to be used in the containment of EBOV outbreaks. The project specifically aims to: (i) complete Phase 1 development of the ChAd3-EBO Z vaccine by supporting a clinical study conducted in Lausanne, Switzerland (WP2); (ii) evaluate the ChAd3-EBO Z vaccine in Phase 2 testing on adults and children at established clinical study centers in West Africa outside the current most heavily affected countries of Guinea, Sierra Leone, and Liberia (WP3); (iii) investigate immunological effects of vaccination and the effect of booster vaccination (WP4) and (iv) centrally manage and analyse clinical study data (WP5). Besides using an innovative vaccine technology, much of the innovation of this program will reside in its capacity to implement vaccine evaluation under significant time pressure and complex logistical challenges while maintaining appropriate quality standards.