Project acronym AimingT6SS
Project Mechanisms of dynamic localization of the bacterial Type 6 secretion system assembly
Researcher (PI) Marek BASLER
Host Institution (HI) UNIVERSITAT BASEL
Call Details Consolidator Grant (CoG), LS6, ERC-2019-COG
Summary The Type 6 secretion system (T6SS) allows Gram-negative bacteria to deliver toxins into both eukaryotic and bacterial target cells and thus cause disease or kill competitors. T6SS is composed of four main parts: a membrane complex, a baseplate and a long spring-like sheath wrapped around an inner tube. Sheath contraction generates a large amount of energy to push the tube with associated toxins through the baseplate and membrane complex out of the cell. However, the reach of the T6SS tube is limited and thus a direct contact with the target membrane and precise positioning of T6SS assembly is required for protein translocation. In this proposal, we will unravel principles of spatial and temporal coordination of T6SS assembly that we have recently observed in several bacterial species. We will study how cells sense attacks from neighboring bacteria to dynamically localize its T6SS. We will describe how bacteria initiate and position T6SS assembly in response to physical cell-cell interactions. We will identify the principles and the role of T6SS localization in intracellular pathogens. Using genetic and biochemical approaches, we will identify and characterize proteins interacting with the core components of T6SS and test their role in initiation and positioning of T6SS assembly. We will search for peptidoglycan remodeling enzymes required for T6SS assembly. We will use advanced microscopy techniques to describe dynamic localization of proteins upon T6SS activation to establish the order of their assembly. We will quantify how much T6SS aiming increases efficiency of protein delivery and T6SS function during bacterial competition and pathogenesis. Overall, we will unravel novel principles of spatial and temporal control of localization of protein complexes and show how this allows bacteria to quickly respond to external cues and interact with their environment.
Summary
The Type 6 secretion system (T6SS) allows Gram-negative bacteria to deliver toxins into both eukaryotic and bacterial target cells and thus cause disease or kill competitors. T6SS is composed of four main parts: a membrane complex, a baseplate and a long spring-like sheath wrapped around an inner tube. Sheath contraction generates a large amount of energy to push the tube with associated toxins through the baseplate and membrane complex out of the cell. However, the reach of the T6SS tube is limited and thus a direct contact with the target membrane and precise positioning of T6SS assembly is required for protein translocation. In this proposal, we will unravel principles of spatial and temporal coordination of T6SS assembly that we have recently observed in several bacterial species. We will study how cells sense attacks from neighboring bacteria to dynamically localize its T6SS. We will describe how bacteria initiate and position T6SS assembly in response to physical cell-cell interactions. We will identify the principles and the role of T6SS localization in intracellular pathogens. Using genetic and biochemical approaches, we will identify and characterize proteins interacting with the core components of T6SS and test their role in initiation and positioning of T6SS assembly. We will search for peptidoglycan remodeling enzymes required for T6SS assembly. We will use advanced microscopy techniques to describe dynamic localization of proteins upon T6SS activation to establish the order of their assembly. We will quantify how much T6SS aiming increases efficiency of protein delivery and T6SS function during bacterial competition and pathogenesis. Overall, we will unravel novel principles of spatial and temporal control of localization of protein complexes and show how this allows bacteria to quickly respond to external cues and interact with their environment.
Max ERC Funding
2 493 650 €
Duration
Start date: 2021-01-01, End date: 2025-12-31
Project acronym B-DOMINANCE
Project B Cell Immunodominance in Antiviral Immunity
Researcher (PI) Davide Angeletti
Host Institution (HI) GOETEBORGS UNIVERSITET
Call Details Starting Grant (StG), LS6, ERC-2019-STG
Summary This proposal aims at understanding how B cell specificity and immunodominance shape primary and secondary humoral responses to influenza A virus. Influenza A virus is a relevant human pathogen causing a considerable yearly death toll and economic burden to society. Immunodominance is a major driving force of adaptive immunity and defines the hierarchical recognition of epitopes on the same antigen. Previous studies analysing B cell dynamics in primary and secondary responses have been mainly focusing on simple antigens and competition between B cell clones of the same family. Investigation using complex antigens and examining interclonal competition are surprisingly scarce. Influenza hemagglutinin (HA) is a prime candidate to study immunodominance in B cells. I have generated a set of mutant viruses that will allow for an unprecedented investigation into immunodominance and B cell interclonal competition in primary and secondary responses. These viruses can be used to isolate and enumerate antibody and B cells specific for different epitopes on the same complex antigen (HA). I will use these unique tools in combination with state-of-the-art immunological methods, multi-colour flow cytometry and single cells RNA sequencing paired with B cell receptor sequencing to gain fundamental insights into B cell regulation and anti-viral humoral responses. I will i) study the link between B cell receptor characteristics, specificity and B cell fate decisions in primary responses, ii) characterize the relative contribution of pre-existing B cells, serum antibodies and CD4 T cells for immunodominance of secondary responses, iii) define immunodominance in human individuals, repeatedly exposed to influenza virus. I expect this project to critically improve our understanding of basic B cell biology with the long-term benefit of improving current vaccination against variable viral pathogens.
Summary
This proposal aims at understanding how B cell specificity and immunodominance shape primary and secondary humoral responses to influenza A virus. Influenza A virus is a relevant human pathogen causing a considerable yearly death toll and economic burden to society. Immunodominance is a major driving force of adaptive immunity and defines the hierarchical recognition of epitopes on the same antigen. Previous studies analysing B cell dynamics in primary and secondary responses have been mainly focusing on simple antigens and competition between B cell clones of the same family. Investigation using complex antigens and examining interclonal competition are surprisingly scarce. Influenza hemagglutinin (HA) is a prime candidate to study immunodominance in B cells. I have generated a set of mutant viruses that will allow for an unprecedented investigation into immunodominance and B cell interclonal competition in primary and secondary responses. These viruses can be used to isolate and enumerate antibody and B cells specific for different epitopes on the same complex antigen (HA). I will use these unique tools in combination with state-of-the-art immunological methods, multi-colour flow cytometry and single cells RNA sequencing paired with B cell receptor sequencing to gain fundamental insights into B cell regulation and anti-viral humoral responses. I will i) study the link between B cell receptor characteristics, specificity and B cell fate decisions in primary responses, ii) characterize the relative contribution of pre-existing B cells, serum antibodies and CD4 T cells for immunodominance of secondary responses, iii) define immunodominance in human individuals, repeatedly exposed to influenza virus. I expect this project to critically improve our understanding of basic B cell biology with the long-term benefit of improving current vaccination against variable viral pathogens.
Max ERC Funding
1 481 697 €
Duration
Start date: 2019-12-01, End date: 2024-11-30
Project acronym Bac2MUC
Project Bacteria-mucin interactions – Shaping intestinal epithelial responses in health and disease
Researcher (PI) Karin STRIJBIS
Host Institution (HI) UNIVERSITEIT UTRECHT
Call Details Starting Grant (StG), LS6, ERC-2019-STG
Summary The intestinal microbiota consists of beneficial commensal bacteria and pathobionts that cause inflammation. The intestinal mucus layer dictates how specific members of the microbiota affect health and disease. The mucus layer consists of soluble mucins and epithelial transmembrane (TM) mucins that regulate host responses. The molecular mechanisms as to how the intestinal microbiota affect the functions of TM mucins is largely unknown. My recent work shows that TM mucin MUC1 is a key receptor for Salmonella invasion into polarized epithelial cells. We also discovered that MUC13 is a central regulator of epithelial barrier formation. I hypothesize that bacteria-mucin interactions shape epithelial responses by stimulating healthy barrier formation, driving inflammation or mediating bacterial invasion. My aim is to unravel molecular mechanisms via which distinct bacterial species regulate the functions of TM mucins MUC1 and MUC13 in the intestine. The key objectives of Bac2MUC are to: 1. Identify commensal and pathogenic bacteria that target TM mucins 2. Elucidate TM mucin signaling pathways activated by commensal and pathogenic bacteria 3. Determine the function of TM mucins during inflammation and invasion 4. Utilize bacteria-TM mucin interactions to unravel healthy epithelial barrier regulation I will use an innovative large-scale screening platform to identify novel bacteria-mucin interactions. TM mucin signaling pathways during bacterial interaction will be characterized by sortase technology. Cutting-edge technologies such as CRISPR/Cas9 genome editing and advanced microscopy will be applied in established bacterial infection assays with intestinal cell lines and organoids. Bac2MUC is an ambitious and ground-breaking project that will address, for the first time, the complex interplay between intestinal bacteria and TM mucins. This project will contribute to clinical strategies that prevent intestinal inflammation and improve mucosal barrier function.
Summary
The intestinal microbiota consists of beneficial commensal bacteria and pathobionts that cause inflammation. The intestinal mucus layer dictates how specific members of the microbiota affect health and disease. The mucus layer consists of soluble mucins and epithelial transmembrane (TM) mucins that regulate host responses. The molecular mechanisms as to how the intestinal microbiota affect the functions of TM mucins is largely unknown. My recent work shows that TM mucin MUC1 is a key receptor for Salmonella invasion into polarized epithelial cells. We also discovered that MUC13 is a central regulator of epithelial barrier formation. I hypothesize that bacteria-mucin interactions shape epithelial responses by stimulating healthy barrier formation, driving inflammation or mediating bacterial invasion. My aim is to unravel molecular mechanisms via which distinct bacterial species regulate the functions of TM mucins MUC1 and MUC13 in the intestine. The key objectives of Bac2MUC are to: 1. Identify commensal and pathogenic bacteria that target TM mucins 2. Elucidate TM mucin signaling pathways activated by commensal and pathogenic bacteria 3. Determine the function of TM mucins during inflammation and invasion 4. Utilize bacteria-TM mucin interactions to unravel healthy epithelial barrier regulation I will use an innovative large-scale screening platform to identify novel bacteria-mucin interactions. TM mucin signaling pathways during bacterial interaction will be characterized by sortase technology. Cutting-edge technologies such as CRISPR/Cas9 genome editing and advanced microscopy will be applied in established bacterial infection assays with intestinal cell lines and organoids. Bac2MUC is an ambitious and ground-breaking project that will address, for the first time, the complex interplay between intestinal bacteria and TM mucins. This project will contribute to clinical strategies that prevent intestinal inflammation and improve mucosal barrier function.
Max ERC Funding
1 500 000 €
Duration
Start date: 2020-03-01, End date: 2025-02-28
Project acronym BARRIER BREAK
Project Breaking the barrier: How inflammation spreads from skin to joint
Researcher (PI) Andreas Ramming
Host Institution (HI) UNIVERSITATSKLINIKUM ERLANGEN
Call Details Starting Grant (StG), LS6, ERC-2019-STG
Summary Physical barriers of the body and their immunological dysregulation are connected to a variety of inflammatory diseases and therefore an emerging area of interest in medicine. The gut and its microbiome gained center stage, whereas the skin as large primary immunological barrier to the environment is still less appreciated. Psoriatic arthritis (PsA) is a prototypic inflammatory disease which usually starts with skin lesions, before spreading to the musculoskeletal regions. To date, it is still obscure why the inflammatory process in some patients with psoriasis is restrained to the skin, whereas in other patients it extends to tendons and joints. Moreover, disease spreading to the joints associates with local tissue remodelling as evidenced by new bone formation at the insertion site of tendons into the bones. The molecular and cellular regulation of this “skin-joint axis” leading to development of PsA is still unclear but essential to understand organ communication in inflammatory diseases, the identification of potential biomarkers for early recognition of the disease and the development of preventive treatments. We will take advantage of a new model resembling PsA, which was established in our lab, with the aim of (1) studying disease spreading from the skin to musculoskeletal regions, (2) deciphering the molecular mechanisms that lead to uncontrolled local tissue remodeling, and finally (3) testing a new translational approach to prevent spreading of inflammation and tissue remodelling. We plan to adopt cutting-edge techniques to achieve our goals, which in turn will contribute to a better knowledge of the connection between epithelial surfaces and inflammation.
Summary
Physical barriers of the body and their immunological dysregulation are connected to a variety of inflammatory diseases and therefore an emerging area of interest in medicine. The gut and its microbiome gained center stage, whereas the skin as large primary immunological barrier to the environment is still less appreciated. Psoriatic arthritis (PsA) is a prototypic inflammatory disease which usually starts with skin lesions, before spreading to the musculoskeletal regions. To date, it is still obscure why the inflammatory process in some patients with psoriasis is restrained to the skin, whereas in other patients it extends to tendons and joints. Moreover, disease spreading to the joints associates with local tissue remodelling as evidenced by new bone formation at the insertion site of tendons into the bones. The molecular and cellular regulation of this “skin-joint axis” leading to development of PsA is still unclear but essential to understand organ communication in inflammatory diseases, the identification of potential biomarkers for early recognition of the disease and the development of preventive treatments. We will take advantage of a new model resembling PsA, which was established in our lab, with the aim of (1) studying disease spreading from the skin to musculoskeletal regions, (2) deciphering the molecular mechanisms that lead to uncontrolled local tissue remodeling, and finally (3) testing a new translational approach to prevent spreading of inflammation and tissue remodelling. We plan to adopt cutting-edge techniques to achieve our goals, which in turn will contribute to a better knowledge of the connection between epithelial surfaces and inflammation.
Max ERC Funding
1 487 231 €
Duration
Start date: 2020-01-01, End date: 2024-12-31
Project acronym DissectCMV
Project Creating a comprehensive functional map of the viral and host factors in HCMV infection
Researcher (PI) Noam STERN-GINOSSAR
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Consolidator Grant (CoG), LS6, ERC-2019-COG
Summary The herpesvirus human cytomegalovirus (HCMV), the largest known human virus, is a ubiquitous pathogen that persistently infects the majority of the world's population through the establishment of latency. Although asymptomatic in most healthy individuals, HCMV can lead to a severe congenital disease, as well as morbidity and mortality in immunocompromised adults. Despite the prevalence and pathogenicity of HCMV, many fundamental questions about this pathogen remain open. We still do not know the complete list of functional elements in HCMV's complex genome and how these contribute to infection progression and latency, we do not understand the determinants that govern infection outcome, and we are missing tools that will facilitate systematic dissection of the host and viral factors that are needed for HCMV infection in different cell types.
In this proposal, we suggest to employ our expertise and to develop unique toolsets to shed light on the host and viral factors that regulate the HCMV life cycle. We propose to combine state-of-the art high-throughput tools with mechanistic studies to comprehensively characterize the viral elements that regulate HCMV progression (aim 1), decipher the determinants that dictate infection outcome (lytic vs. latent, aim 2) and develop and implement a sensitive screening platform that will facilitate easy dissection and characterization of HCMV essential components in any cell type (aim 3).
The knowledge generated from these objectives will provide a clearer depiction of the different determinants that control HCMV infection and will generate new tools for the benefit of the community. These in turn could help to expand our therapeutic options. More broadly, with its comprehensive and complementary approaches, this work will provide a paradigm for the study of other herpesviruses and for understanding complex host-pathogen interactions.
Summary
The herpesvirus human cytomegalovirus (HCMV), the largest known human virus, is a ubiquitous pathogen that persistently infects the majority of the world's population through the establishment of latency. Although asymptomatic in most healthy individuals, HCMV can lead to a severe congenital disease, as well as morbidity and mortality in immunocompromised adults. Despite the prevalence and pathogenicity of HCMV, many fundamental questions about this pathogen remain open. We still do not know the complete list of functional elements in HCMV's complex genome and how these contribute to infection progression and latency, we do not understand the determinants that govern infection outcome, and we are missing tools that will facilitate systematic dissection of the host and viral factors that are needed for HCMV infection in different cell types.
In this proposal, we suggest to employ our expertise and to develop unique toolsets to shed light on the host and viral factors that regulate the HCMV life cycle. We propose to combine state-of-the art high-throughput tools with mechanistic studies to comprehensively characterize the viral elements that regulate HCMV progression (aim 1), decipher the determinants that dictate infection outcome (lytic vs. latent, aim 2) and develop and implement a sensitive screening platform that will facilitate easy dissection and characterization of HCMV essential components in any cell type (aim 3).
The knowledge generated from these objectives will provide a clearer depiction of the different determinants that control HCMV infection and will generate new tools for the benefit of the community. These in turn could help to expand our therapeutic options. More broadly, with its comprehensive and complementary approaches, this work will provide a paradigm for the study of other herpesviruses and for understanding complex host-pathogen interactions.
Max ERC Funding
2 000 000 €
Duration
Start date: 2020-06-01, End date: 2025-05-31
Project acronym GUT-SEQ
Project Single-cell analysis of intestinal lymphocytes reveals targets for treatment of inflammatory bowel disease
Researcher (PI) Jenny MJÖSBERG
Host Institution (HI) KAROLINSKA INSTITUTET
Call Details Starting Grant (StG), LS6, ERC-2019-STG
Summary Inflammatory bowel disease (IBD) constitutes an increasing global health burden, yet effective treatments are lacking. Hampering rationale treatment strategies, the human intestinal immune system remains largely unexplored. I have made seminal contributions to the discovery and characterization of innate lymphoid cells (ILCs) (Nat Immunol 2011, 2013 and 2016, Immunity 2012), revealing that in addition to antigen-specific adaptive T cells, innate equivalents play important roles in mucosal immunity. Determining the complementarity and redundancy of these two lymphocyte systems, acting in concert, is important for our understanding of inflammatory diseases and the development of novel therapies. For this proposal, I am in the beneficial position of having access to unique patient samples as well as established methods for single-cell RNA-sequencing to perform an ambitious and comprehensive molecular dissection of the human intestinal lymphocyte compartments in IBD. With this approach, I will determine parallels between known, and identify novel, subsets of tissue-resident, inflammation-associated, innate and adaptive lymphocytes. Building on this unprecedented molecular characterization, we will take on some of the most pressing clinical problems in IBD by performing longitudinal assessments of intestinal lymphocytes from IBD patients on conventional and biological treatments. As only a fraction of patients respond to treatment, this approach provides a golden opportunity to unveil immunological signatures of treatment response and “drug-induced transformation” of inflammation in non-responders. Furthermore, we will unfold critical disease mechanisms and reveal novel therapy targets and how they can be used to personalize treatment. In summary, my ambitious, yet feasible, proposal combines state-of-the-art technology with access to unique patient materials. My studies are likely to advance our understanding of the complex intestinal lymphocyte network in IBD.
Summary
Inflammatory bowel disease (IBD) constitutes an increasing global health burden, yet effective treatments are lacking. Hampering rationale treatment strategies, the human intestinal immune system remains largely unexplored. I have made seminal contributions to the discovery and characterization of innate lymphoid cells (ILCs) (Nat Immunol 2011, 2013 and 2016, Immunity 2012), revealing that in addition to antigen-specific adaptive T cells, innate equivalents play important roles in mucosal immunity. Determining the complementarity and redundancy of these two lymphocyte systems, acting in concert, is important for our understanding of inflammatory diseases and the development of novel therapies. For this proposal, I am in the beneficial position of having access to unique patient samples as well as established methods for single-cell RNA-sequencing to perform an ambitious and comprehensive molecular dissection of the human intestinal lymphocyte compartments in IBD. With this approach, I will determine parallels between known, and identify novel, subsets of tissue-resident, inflammation-associated, innate and adaptive lymphocytes. Building on this unprecedented molecular characterization, we will take on some of the most pressing clinical problems in IBD by performing longitudinal assessments of intestinal lymphocytes from IBD patients on conventional and biological treatments. As only a fraction of patients respond to treatment, this approach provides a golden opportunity to unveil immunological signatures of treatment response and “drug-induced transformation” of inflammation in non-responders. Furthermore, we will unfold critical disease mechanisms and reveal novel therapy targets and how they can be used to personalize treatment. In summary, my ambitious, yet feasible, proposal combines state-of-the-art technology with access to unique patient materials. My studies are likely to advance our understanding of the complex intestinal lymphocyte network in IBD.
Max ERC Funding
1 500 000 €
Duration
Start date: 2020-07-01, End date: 2025-06-30
Project acronym MyeFattyLiver
Project Unravelling the heterogeneity and functions of hepatic myeloid cells in Non-Alcoholic Fatty Liver Disease
Researcher (PI) Charlotte Louise SCOTT
Host Institution (HI) VIB VZW
Call Details Starting Grant (StG), LS6, ERC-2019-STG
Summary Non-alcoholic fatty liver disease (NAFLD) results from accumulation of excessive fat in the liver. It encompasses simple steatosis (fatty liver) progressing through non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma. It is the most common cause of chronic liver disease in western countries and is predicted to be the main cause of liver transplantation by 2030. As such NAFLD represents a significant clinical burden for which to date, there is no effective treatment. Multiple ‘hits’ are thought to contribute to the progression from steatosis to NASH. One of these ‘hits’ is activation of the immune system and the ensuing inflammatory response. Hepatic myeloid cells, including mononuclear phagocytes (MNPs) are thought to play an essential role in this, sensing excess lipids and other danger signals and initiating immune responses. However, MNPs represent a highly heterogeneous population, including multiple subtypes of dendritic cells and macrophages. To date these have been studied as a group rather than as individual cell types, leading to them being ascribed multiple and often contradictory roles depending on the experimental set up. Thus their specific contributions to NAFLD still remain unclear. I hypothesize that by dissecting the phenotypic and functional heterogeneity of hepatic MNPs, we will be able to unravel their roles in NAFLD and in the progression to NASH. Single cell technologies such as single cell RNA sequencing have revolutionised our ability to understand cellular heterogeneity. In addition, they have facilitated the development of novel genetic tools to study functions of specific cell types in vivo. I aim to use this technology and more specific in vivo tools to understand MNP phenotypic and functional heterogeneity in NAFLD in mice and men. This is essential for the development of novel therapeutic strategies targeting myeloid cells in what is becoming one of the biggest health challenges in the western world.
Summary
Non-alcoholic fatty liver disease (NAFLD) results from accumulation of excessive fat in the liver. It encompasses simple steatosis (fatty liver) progressing through non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma. It is the most common cause of chronic liver disease in western countries and is predicted to be the main cause of liver transplantation by 2030. As such NAFLD represents a significant clinical burden for which to date, there is no effective treatment. Multiple ‘hits’ are thought to contribute to the progression from steatosis to NASH. One of these ‘hits’ is activation of the immune system and the ensuing inflammatory response. Hepatic myeloid cells, including mononuclear phagocytes (MNPs) are thought to play an essential role in this, sensing excess lipids and other danger signals and initiating immune responses. However, MNPs represent a highly heterogeneous population, including multiple subtypes of dendritic cells and macrophages. To date these have been studied as a group rather than as individual cell types, leading to them being ascribed multiple and often contradictory roles depending on the experimental set up. Thus their specific contributions to NAFLD still remain unclear. I hypothesize that by dissecting the phenotypic and functional heterogeneity of hepatic MNPs, we will be able to unravel their roles in NAFLD and in the progression to NASH. Single cell technologies such as single cell RNA sequencing have revolutionised our ability to understand cellular heterogeneity. In addition, they have facilitated the development of novel genetic tools to study functions of specific cell types in vivo. I aim to use this technology and more specific in vivo tools to understand MNP phenotypic and functional heterogeneity in NAFLD in mice and men. This is essential for the development of novel therapeutic strategies targeting myeloid cells in what is becoming one of the biggest health challenges in the western world.
Max ERC Funding
1 500 000 €
Duration
Start date: 2019-12-01, End date: 2024-11-30
Project acronym NICHEADAPT
Project Deciphering the niche adaptations of a gut commensal involved in educating the host immune system
Researcher (PI) Pamela Schnupf
Host Institution (HI) INSTITUT NATIONAL DE LA SANTE ET DE LA RECHERCHE MEDICALE
Call Details Consolidator Grant (CoG), LS6, ERC-2019-COG
Summary The gut microbiota plays an integral part in driving the postnatal maturation of the gut immune system and in protecting the host from pathogens. The commensal segmented filamentous bacteria (SFB) plays a critical role in these processes through its intimate attachment to the ileal epithelium using a unique pointed tip structure on its unicellular ‘infectious’ particle. SFB induces a broad pro-inflammatory immune activation, and notably a striking induction of IgA and Th17 cell responses, that fosters pathogen resistance but can also exacerbate disease severity in a number of autoimmune models, making SFB an important microbe in health and disease. SFB is found in many vertebrate species, including humans, and SFB monocolonization has allowed a detail study of its immunostimulatory potential. However, the unique and complex life-cycle of SFB and SFB’s interaction with the host has remained poorly understood due to a lack of in vitro culturing techniques. We recently overcame this hurdle by establishing the first in vitro SFB-host cell co-culturing system. Using this system, unicellular SFB were discovered to be flagellated and to stimulate TLR5 signaling, revealing a missing link of immunological importance in the SFB life-cycle. This important developmental stage will now be further characterized and its immunological consequence assessed using gnotobiology. State-of-the-art microscopy techniques will be employed to characterize in detail the SFB life-cycle and novel structures discovered during in vitro growth. Unicellular SFB surface proteins will be identified using mass spectrometry, localized on the bacterium and tested for their ability to mediate host cell attachment. In addition, next generation sequencing and transcriptomics will be used to assess SFB genome evolution and SFB niche constraints. Together, this work will lead to a detailed view of the SFB life-cycle and how SFB has adapted to its unique replicative niche at the epithelial surface.
Summary
The gut microbiota plays an integral part in driving the postnatal maturation of the gut immune system and in protecting the host from pathogens. The commensal segmented filamentous bacteria (SFB) plays a critical role in these processes through its intimate attachment to the ileal epithelium using a unique pointed tip structure on its unicellular ‘infectious’ particle. SFB induces a broad pro-inflammatory immune activation, and notably a striking induction of IgA and Th17 cell responses, that fosters pathogen resistance but can also exacerbate disease severity in a number of autoimmune models, making SFB an important microbe in health and disease. SFB is found in many vertebrate species, including humans, and SFB monocolonization has allowed a detail study of its immunostimulatory potential. However, the unique and complex life-cycle of SFB and SFB’s interaction with the host has remained poorly understood due to a lack of in vitro culturing techniques. We recently overcame this hurdle by establishing the first in vitro SFB-host cell co-culturing system. Using this system, unicellular SFB were discovered to be flagellated and to stimulate TLR5 signaling, revealing a missing link of immunological importance in the SFB life-cycle. This important developmental stage will now be further characterized and its immunological consequence assessed using gnotobiology. State-of-the-art microscopy techniques will be employed to characterize in detail the SFB life-cycle and novel structures discovered during in vitro growth. Unicellular SFB surface proteins will be identified using mass spectrometry, localized on the bacterium and tested for their ability to mediate host cell attachment. In addition, next generation sequencing and transcriptomics will be used to assess SFB genome evolution and SFB niche constraints. Together, this work will lead to a detailed view of the SFB life-cycle and how SFB has adapted to its unique replicative niche at the epithelial surface.
Max ERC Funding
1 999 948 €
Duration
Start date: 2021-01-01, End date: 2025-12-31
Project acronym PATHOCODE
Project Molecular pathology of anti-viral T cell responses in the central nervous system
Researcher (PI) Doron MERKLER
Host Institution (HI) UNIVERSITE DE GENEVE
Call Details Consolidator Grant (CoG), LS6, ERC-2019-COG
Summary "Immune responses against viruses in the central nervous system (CNS) can result in devastating outcomes. Even non-cytolytic CD8+ T cell interactions, which purge viruses from neurons without triggering cell death, can induce permanent damage. Yet, how this immune response irreversibly disrupts neuronal homeostasis remains unclear.
Here, we will elucidate the molecular mechanisms that underlie non-cytolytic CD8+ T cell engagement with infected neurons and their consequences on neuron function in vivo. We hypothesize that inflammatory signalling in neurons, induced by non-cytolytic CD8+ T cell interactions, triggers metabolic and epigenetic changes that underpin permanent neuronal dysfunction.
""PATHOCODE"" will test this hypothesis by harnessing a unique animal model of T cell-driven virus encephalitis in the following objectives: 1. Discern neuronal subset-specific vulnerabilities and antigen-dependent versus bystander effects in the inflamed CNS. We will perform single nucleus RNA sequencing to examine whether T cell engagement (a) differentially affects molecularly distinct neurons, and (b) affects non-targeted, uninfected neurons. 2. Uncover the consequences of non-cytolytic T cell engagement on neuronal metabolism. We will use cell-specific mitochondrial reporter mice to investigate immune-driven metabolic adaptation of neurons in vivo. 3. Determine how non-cytolytic T cell engagement affects the neuronal epigenome. We will employ cell-specific nucleus/ribosome reporter mice to elucidate how T cell engagement affects the translatome and epigenome of infected cells. 4. Rescue T cell-mediated neuronal dysfunction by restoring metabolic pathways. We will exploit recent CRISPR/Cas9 technological advances to restore neuronal gene expression and uncover the relevance of immune-driven metabolic and epigenomic changes to disease. Our study will thus provide novel molecular concepts about immune-driven neuronal alterations in CNS inflammatory diseases."
Summary
"Immune responses against viruses in the central nervous system (CNS) can result in devastating outcomes. Even non-cytolytic CD8+ T cell interactions, which purge viruses from neurons without triggering cell death, can induce permanent damage. Yet, how this immune response irreversibly disrupts neuronal homeostasis remains unclear.
Here, we will elucidate the molecular mechanisms that underlie non-cytolytic CD8+ T cell engagement with infected neurons and their consequences on neuron function in vivo. We hypothesize that inflammatory signalling in neurons, induced by non-cytolytic CD8+ T cell interactions, triggers metabolic and epigenetic changes that underpin permanent neuronal dysfunction.
""PATHOCODE"" will test this hypothesis by harnessing a unique animal model of T cell-driven virus encephalitis in the following objectives: 1. Discern neuronal subset-specific vulnerabilities and antigen-dependent versus bystander effects in the inflamed CNS. We will perform single nucleus RNA sequencing to examine whether T cell engagement (a) differentially affects molecularly distinct neurons, and (b) affects non-targeted, uninfected neurons. 2. Uncover the consequences of non-cytolytic T cell engagement on neuronal metabolism. We will use cell-specific mitochondrial reporter mice to investigate immune-driven metabolic adaptation of neurons in vivo. 3. Determine how non-cytolytic T cell engagement affects the neuronal epigenome. We will employ cell-specific nucleus/ribosome reporter mice to elucidate how T cell engagement affects the translatome and epigenome of infected cells. 4. Rescue T cell-mediated neuronal dysfunction by restoring metabolic pathways. We will exploit recent CRISPR/Cas9 technological advances to restore neuronal gene expression and uncover the relevance of immune-driven metabolic and epigenomic changes to disease. Our study will thus provide novel molecular concepts about immune-driven neuronal alterations in CNS inflammatory diseases."
Max ERC Funding
1 999 954 €
Duration
Start date: 2020-08-01, End date: 2025-07-31
Project acronym REpAIR
Project Spatio-Temporal Regulation of Inflammation and Tissue Regeneration: Studying the immune system - tissue - microbiota communication to develop targeted therapies for immune-mediated diseases and cancer
Researcher (PI) Samuel Huber
Host Institution (HI) UNIVERSITAETSKLINIKUM HAMBURG-EPPENDORF
Call Details Consolidator Grant (CoG), LS6, ERC-2019-COG
Summary Inflammation is fundamental to promote tissue regeneration upon injury, and in turn, the resolution of the immune response. Physiological tissue regeneration depends on fine-tuned interaction between the immune system, the tissue, and the microbiota. However, the complex communication between these three components and the molecules that mediate it are unclear. Understanding this is fundamental to prevent immune-mediated diseases and even cancer. This is particularly important at mucosal surfaces, where continued regeneration occurs. Therefore, we hypothesize that inflammatory bowel disease (IBD) and colorectal cancer (CRC) are a consequence of a miscommunication between these components.
Interleukin-22 (IL-22) is one key orchestrator of this communication: It is produced by immune cells and by acting on intestinal epithelial cells, it modulates the composition of the microbiota and promotes tissue regeneration. However, IL-22 can also promote both chronic inflammation and cancer. Exactly what regulates these paradoxical effects remains unclear. Of note, there is an endogenous inhibitor of IL-22, namely IL-22 binding protein (IL-22BP), which blocks IL-22 activity. We hypothesize that a misguided spatio-temporal regulation of the IL-22 – IL-22BP axis is the cause of pathogenic effects of IL-22.
In particular, we will analyse: (i) the location, and the functional and molecular heterogeneity; (ii) the origin and fate of IL-22 and IL-22BP producing immune cells; and (iii) the role of the microbiota in regulating them. To this end, we will use new transgenic and gnotobiotic mouse models, single cell RNA sequencing and human samples.
In short, by studying the IL-22 - IL-22BP axis, we will understand how the complex interactions between the immune system, the tissue, and the microbiota lead to either physiological or pathological tissue regeneration. This will provide the basis for therapies controlling inflammation and tissue regeneration in a spatio-temporal manner.
Summary
Inflammation is fundamental to promote tissue regeneration upon injury, and in turn, the resolution of the immune response. Physiological tissue regeneration depends on fine-tuned interaction between the immune system, the tissue, and the microbiota. However, the complex communication between these three components and the molecules that mediate it are unclear. Understanding this is fundamental to prevent immune-mediated diseases and even cancer. This is particularly important at mucosal surfaces, where continued regeneration occurs. Therefore, we hypothesize that inflammatory bowel disease (IBD) and colorectal cancer (CRC) are a consequence of a miscommunication between these components.
Interleukin-22 (IL-22) is one key orchestrator of this communication: It is produced by immune cells and by acting on intestinal epithelial cells, it modulates the composition of the microbiota and promotes tissue regeneration. However, IL-22 can also promote both chronic inflammation and cancer. Exactly what regulates these paradoxical effects remains unclear. Of note, there is an endogenous inhibitor of IL-22, namely IL-22 binding protein (IL-22BP), which blocks IL-22 activity. We hypothesize that a misguided spatio-temporal regulation of the IL-22 – IL-22BP axis is the cause of pathogenic effects of IL-22.
In particular, we will analyse: (i) the location, and the functional and molecular heterogeneity; (ii) the origin and fate of IL-22 and IL-22BP producing immune cells; and (iii) the role of the microbiota in regulating them. To this end, we will use new transgenic and gnotobiotic mouse models, single cell RNA sequencing and human samples.
In short, by studying the IL-22 - IL-22BP axis, we will understand how the complex interactions between the immune system, the tissue, and the microbiota lead to either physiological or pathological tissue regeneration. This will provide the basis for therapies controlling inflammation and tissue regeneration in a spatio-temporal manner.
Max ERC Funding
1 999 687 €
Duration
Start date: 2020-06-01, End date: 2025-05-31
