Projects

Funding: The International Human Frontier Science Program Organization (HFSP), 1.106.000 EUR

Project Details:
Insect cell membranes differ from mammalian membranes by deformability, lipid content and distribution. Enveloped insect-borne viruses require intimate interactions with cellular
membranes to enter cells, replicate their genomes in cells and bud from cells. Despite fundamental biophysical differences between insect and mammalian membranes, viruses can productively infect cells from both phyla. Decades of studies on insect-borne viruses have not addressed the machinery of insect membrane deformation and its exploitation by viruses. Working at the interface of insect genetics, biophysics and infection biology, our newly formed team has assembled innovative technologies to break through this barrier in the field. Through the combined expertise of the PIs, we will: 1. Employ gene editing libraries in insect cells to identify host factors steering virus - membrane interactions; 2. Image membrane deformation at high resolution; 3. Assess the impact of membrane deformation on permissiveness to insectborne viruses. These studies will provide insight into mechanisms driving insect membrane shape and revolutionize our understanding of virus adaptation across fundamentally different
species.

Cooperation Partners:

Dr. Nicholas Ariotti, Institute for Molecular Bioscience, Australia

Dr. Norbert Perrimon, Harvard Medical School, USA

Funding: Deutsche Forschungsgesellschaft (DFG), 110.700 EUR

Project Details:
Tetraspanins are evolutionary conserved integral membrane proteins of 200-350 amino acid lengths. Through their large extracellular loop they mediate protein - protein and protein - lipid interactions in cellular membranes thereby shaping membrane microdomains called ?tetraspanin webs?. In humans and mice 33 tetraspanins are described and mosquito species express at least 15 tetraspanin orthologs. In mammalian cells, tetraspanins are host co-factors for several viruses including papillomaviruses, influenza virus, hepatitis C virus, HIV-1 and coronaviruses (Gerold et al., 2015; Bruening et al. 2018; Banse et al., 2018; Alberione et al. 2020; Palor et al., 2020). For hepatitis C virus, colleagues and we showed that the tetraspanin CD81 is a host range determining factor (Vogt et al. 2013; Scull et al., 2015; von Schaewen et al., 2016).
The proposed project aims at characterizing in detail, which of the 33 human tetraspanins in addition to CD81 are host factors for alphaviruses and whether tetraspanins from reservoir species, dead end host species and transmitting mosquito vectors serve as host factors of alphaviruses. Thereby the work will contribute to the understanding of the molecular composition and function of alphavirus replication complexes and determine the role of tetraspanins in species range, transmission and consequently emergence of alphaviruses.

Funding: BMBF, 198.361 EUR

Project Details:
Noroviruses are the most prevalent viral cause of acute gastroenteritis. At least 40 noroviruses have been
described, with new variants regularly emerging. Norovirus evolution, emergence, and circulation are not
entirely understood, especially the role of a potential animal reservoir is insufficiently investigated. Several
lines of evidence suggest norovirus transmission between humans and animals. However, there is no in
vitro system to investigate interspecies transmission to date. Here we set out to establish an ex vivo system
based on intestinal biopsies of various animal species to investigate interspecies norovirus transmission
experimentally. We will use biopsies of dogs, pigs, and chickens as they are highly abundant and kept in
close contact with humans. The risk for transmission is therefore increased. Precision-cut intestinal slices
will be set up and used to investigate norovirus binding, entry/internalization, and replication in the
respective host tissues. Furthermore, the role of the known susceptibility factors, the histo blood group
antigens, will be investigated. Once established, this explant system will allow the investigation of norovirus
receptors, attachment factors and other host determinants in humans and non-human animal species. The
system will also be valuable for investigating other enteric viruses with zoonotic potential, including
coronaviruses, influenza viruses, and dog and pig-specific noroviruses.

Funding: BMBF, 122.004 EUR

Project Details:
Every year, about 750,000 people die from mosquito-borne diseases, including malaria, dengue fever, rift valley fever and chikungunya fever. The incidence of these diseases is expected to increase significantly over the next few decades, as the ranges of several mosquito species are expanding due to climate
change. Mosquitoes not only transmit diseases, but can also influence the severity of the diseases they transmit. It has been shown in experimental infections of animals, the transmission of arboviruses by mosquito bites compared to artificial infection can lead to an increase in the severity of the disease. In
addition, it is known that the saliva of insects and ticks can promote the progression of vector-borne diseases. The skin is the first organ to be exposed to an arbovirus infection, thus the initial infection events also significantly determine the course of the disease. It is therefore essential for many to investigate a natural infection of the skin via a mosquito bite. So far, this could only be achieved by in-vivo experiments (animal experiments). In this project, an alternative is to be developed by replacing animal models with human skin explants for ethical and physiological reasons. The challenge of this study will be to establish an assay in which mosquitoes can use the skin implants as potential hosts. The goal is a successful biting of the skin explants by mosquitoes. Exemplarily, in a second step the skin explants should be infected via bite of Rift Valley Fever Virus (RVFV) and/or Chikungunya Virus (CHIKV)-infected mosquitoes. If
successful, the project results will allow to choose from different models for future research questions.

Funding: Europa-Programm des Niedersächsischen Ministeriums für Wissenschaft und Kultur aus Mitteln von SPRUNG, 79.770 EUR

Project Details:
The focus is on studying the evolution of viruses in the two hosts arthropods (mosquitoes, ticks) and mammals and the implications for host receptor usage.

Cooperation Partners:

Prof. Dr. Félix Rey, Institut Pasteur, Paris, Frankreich

Funding: Deutsche Forschungsgesellschaft (DFG), 398.333 EUR

Project Details:
Virus emergence and re-emergence is an increasing public health
problem as globalization and climate change promote the spread of
infectious disease. This is particularly true for mosquito-borne
infections as mosquitoes continue to spread to new geographic
regions. Alphaviruses such as Chikungunya virus (CHIKV) and
Venezuelan equine encephalitis virus (VEEV) belong to the group of
mosquito-borne viruses, which cause pathology in humans. The re-emerging CHIKV is causing long-lasting arthritis like symptoms, while
VEEV infection leads to encephalitis. Why the two viruses from the
same family cause pathologies in different tissues, i.e. joints versus
central nervous system (CNS), is unclear to date. This gap of
knowledge is reflected by the fact that few host factors for CHIKV and
VEEV are known. Here we capitalize on our findings that the
phosphatidylserine (PS) receptor T cell immunoglobulin mucin
receptor 1 (TIM-1) and a tetraspanin are host factors for CHIKV. We
hypothesize that (a) VEEV also hijacks PS receptors and tetraspanins
to infect human cells, (b) TIM-1 and the tetraspanin interact with
additional proteins to promote infection with CHIKV and possibly
VEEV and (c) that a subset of these host factors contribute to tissue
tropism of CHIKV and VEEV. To test our hypothesis we will initially
use unbiased state of the art quantitative proteomics methods to
identify entry factors and receptors of CHIKV and VEEV. Next we will
screen PS receptors and all 33 human tetraspanins for their role in
VEEV infection by RNA interference in human cells. TIM-1 and
Tetraspanin associated proteins will be identified by proximity labeling
in conjunction with high-resolution affinity enrichment mass
spectrometry. Finally we will investigate the contribution of the
identified host factors to tissue tropism of CHIKV and VEEV using
proteomics, single cell sequencing and virological methods.
Specifically, we will infect skin organotypic raft cultures and determine
the predominantly infected cell type as well as expression levels of
identified host factors in the susceptible versus refractory cells.
Additionally we will integrate expression data from online repositories
and measure proteomes of relevant cell types including fibroblasts
and neuronal cells. Using feature selection approaches, we will
identify host factors, which likely contribute to the distinct tissue
tropism and pathologies caused by CHIKV and VEEV. These host
factors will be systematically knocked out first in relevant cell types
and then in mice to delineate the contribution to disease manifestation
in vitro and in vivo. Taken together, this research program aims at
providing mechanistic insight into the infection processes caused by
two important human pathogens, CHIKV and VEEV. The results will
help understand disease mechanisms and may ultimately reveal drug
targets for therapeutic intervention with Chikungunya fever and
Venezuelan equine encephalitis.

Funding: Deutscher Akademischer Austauschdienst (DAAD), 48.000 EUR

Project Details:
Alphaviruses (family Togaviridae) are emerging and re-emerging small enveloped RNA viruses, which are transmitted from animal reservoirs to humans by mosquitoes and can cause debilitating joint pain or encephalitis. Depending on the reservoir species and the transmitting
mosquito vector they are found in different geographic regions. While Chikungunya virus (CHIKV) and O?nyong?nyong virus (ONNV) were historically restricted to tropical and subtropical climates, Sindbis virus (SINV) and Ross River virus (RRV) are primarily found in Scandinavia and Australia, respectively. Adaptation of CHIKV to new mosquito vectors and global warming led to the occurrence of the virus in Europe, making it a potential public health problem in Germany and neighboring countries. An
introduction of Venezuelan equine encephalitis virus (VEEV), which is circulating in the Americas and causing neurological symptoms in equids and humans, may also be possible in the future. No human vaccines or antiviral drugs against arthritogenic and neurotropic alphaviruses are on the market to date. This is reflected by a gap of knowledge of the molecular mechanism of the infection process and critical host factors involved in alphavirus infection and cross-species transmission.
Recently, our team found that the phosphatidylserine receptor T-cell immunoglobulin and mucin domain 1 (TIM-1) is a CHIKV attachment factor. Another prominent group of phosphatidylserine receptors is the Tyro3, AXL, and MerTK (TAM) receptor tyrosine kinase (RTK) family comprising the three proteins Tyro3, AXL and MerTK. The physiological function of TIM and TAM receptors is to bind and internalize apoptotic
bodies, which expose phosphatidylserine on the outer membrane leaflet. We could show that TIM-1 but not AXL serves as host factor for CHIKV. Moreover, the TIM-1 phosphatidylserine binding domain termed metal ion ligand binding site (MILIBS) is critical for the host factor function of TIM-1 in the context of CHIKV infection. TIM-1 affects binding as well as internalization of CHIKV particles to human cells. Finally, TIM-1 also enhances CHIKV infection in keratinocytes, which are among the first target cells of the virus after mosquito bite.
We therefore hypothesize that alphaviruses including CHIKV will use phosphatidylserine receptors for cell attachment and entry in reservoir species such as non-human primates and in transmitting mosquito vectors. Moreover, we here aim to clarify if virus produced in insect cells also exposes phosphatidylserine and this aids in infection of human cells, i.e. in cross-species transmission. Lastly, we will elucidate, how
phosphatidylserine becomes exposed on the viral envelope.
Thereby the work will contribute to the understanding of the molecular composition of alphavirus particles, the function of alphavirus attachment factors and the role of apoptotic mimicry in cross-species transmission and consequently emergence of alphaviruses.

Funding: DFG, 110.700 EUR

Project Details:
Tetraspanins are evolutionary conserved integral membrane proteins of 200-350 amino acid lengths. Through their large extracellular loop they mediate protein - protein and protein - lipid interactions in cellular membranes thereby shaping membrane microdomains called ?tetraspanin webs?. In humans and mice 33 tetraspanins are described and mosquito species express at least 15 tetraspanin orthologs. In mammalian cells, tetraspanins are host co-factors for several viruses including papillomaviruses, influenza virus, hepatitis C virus, HIV-1 and coronaviruses (Gerold et al., 2015; Bruening et al. 2018; Banse et al., 2018; Alberione et al. 2020; Palor et al., 2020). For hepatitis C virus, colleagues and we showed that the tetraspanin CD81 is a host range determining factor (Vogt et al. 2013; Scull et al., 2015; von Schaewen et al., 2016).
The proposed project aims at characterizing in detail, which of the 33 human tetraspanins in addition to CD81 are host factors for alphaviruses and whether tetraspanins from reservoir species, dead end host species and transmitting mosquito vectors serve as host factors of alphaviruses. Thereby the work will contribute to the understanding of the molecular composition and function of alphavirus replication complexes and determine the role of tetraspanins in species range, transmission and consequently emergence of alphaviruses.

Funding: A128512 MWK Niedersachsen, Volkswagen Stiftung, 1.190.125 EUR

Project Details:
In this study we will collect and analyze more than 108 datapoints (proteomics, genomics, clinical and environmental data) from retrospective and prospective patient cohorts. For the first time, this study
will take into account the recent discovery of the tight association of human norovirus with host cell membranes and proteins and link it to clinical, environmental and ecological niche (microbiota) data.
The translational potential of PRESENt ranges from prognostic and preventive to therapeutic strategies for stratified patient groups. First, we aim to define prognostic biomarkers of severe and chronic gastroenteritis to stratify patient groups. Second, we will investigate how efficient
disinfectants can inactivate patient-derived membrane cloaked norovirus. Third, the microbiome signatures may inform about possibilities of microbiota therapies to alleviate the course of disease in critical patient groups. Finally, the informatics meta-analysis of the retrospective and prospective study will reveal in addition to prognostic biomarkers and microbiome signatures environmental and individual factors, which associate with severe gastroenteritis. In the future, this work will thus pave the way towards better prevention (biomarkers, environmental
factors, individualized disinfectant use) and care (targeting/modifying microbiome or host factors) of severe and chronic viral gastroenteritis.

Results:

https://www.translationsallianz.de/train-platforms/train-projects/present/?L=1

Cooperation Partners:

Prof. Dr. Wolfgang Neijdl, Leibnitz University

Prof. Dr. Michael Marschollek, Hannover Medical School

Dr. Benjamin Heidrich, Hannover Medical School

Dr. Till Strowig, Helmholtz Centre for Infection Research

Prof. Dr. Lothar Jänsch, Helmholtz Centre for Infection Research

Prof. Dr. Thomas F. Schulz, Medizinische Hochschule Hannover

Prof. Dr. Lennart Svensson, Linköping Universität, Schweden

Funding: SprinD GmbH, 263.866 EUR

Project Details:
The viral genome of an RNA virus is released into the cell, where the viral genome is amplified and its transcripts translated into proteins to form more copies the virus. CRISPR/Cas13 enzymes cleave different sites of the viral genome and its transcripts through a combination of crRNAs. Proliferation of the virus is blocked and transcripts to be translated into viral proteins are reduced.

Cooperation Partners:

Universitätsmedizin Göttingen (UMG), Prof. Elisabeth Zeisberg