Project acronym CANCER-DC
Project Dissecting Regulatory Networks That Mediate Dendritic Cell Suppression
Researcher (PI) Oren PARNAS
Host Institution (HI) THE HEBREW UNIVERSITY OF JERUSALEM
Call Details Starting Grant (StG), LS6, ERC-2017-STG
Summary Recent advances have shown that therapeutic manipulations of key cell-cell interactions can have dramatic clinical outcomes. Most notable are several early successes in cancer immunotherapy that target the tumor-T cell interface. However, these successes were only partial. This is likely because the few known interactions are just a few pieces of a much larger puzzle, involving additional signaling molecules and cell types. Dendritic cells (DCs), play critical roles in the induction/suppression of T cells. At early cancer stages, DCs capture tumor antigens and present them to T cells. However, in advanced cancers, the tumor microenvironment (TME) disrupts the crosstalk between DCs and T cells.
We will take a multi-step approach to explore how the TME imposes a suppressive effect on DCs and how to reverse this hazardous effect. First, we will use single cell RNA-seq to search for genes in aggressive human and mouse ovarian tumors that are highly expressed in advanced tumors compared to early tumors and that encode molecules that suppress DC activity. Second, we will design a set of CRISPR screens to find genes that are expressed in DCs and regulate the transfer of the suppressive signals. The screens will be performed in the presence of suppressive molecules to mimic the TME and are expected to uncover many key genes in DCs biology. We will develop a new strategy to find synergistic combinations of genes to target (named Perturb-comb), thereby reversing the effect of local tumor immunosuppressive signals. Lastly, we will examine the effect of modified DCs on T cell activation and proliferation in-vivo, and on tumor growth.
We expect to find: (1) Signaling molecules in the TME that affect the immune system. (2) New cytokines and cell surface receptors that are expressed in DCs and signal to T cells. (3) New key regulators in DC biology and their mechanisms. (4) Combinations of genes to target in DCs that reverse the TME’s hazardous effects.
Summary
Recent advances have shown that therapeutic manipulations of key cell-cell interactions can have dramatic clinical outcomes. Most notable are several early successes in cancer immunotherapy that target the tumor-T cell interface. However, these successes were only partial. This is likely because the few known interactions are just a few pieces of a much larger puzzle, involving additional signaling molecules and cell types. Dendritic cells (DCs), play critical roles in the induction/suppression of T cells. At early cancer stages, DCs capture tumor antigens and present them to T cells. However, in advanced cancers, the tumor microenvironment (TME) disrupts the crosstalk between DCs and T cells.
We will take a multi-step approach to explore how the TME imposes a suppressive effect on DCs and how to reverse this hazardous effect. First, we will use single cell RNA-seq to search for genes in aggressive human and mouse ovarian tumors that are highly expressed in advanced tumors compared to early tumors and that encode molecules that suppress DC activity. Second, we will design a set of CRISPR screens to find genes that are expressed in DCs and regulate the transfer of the suppressive signals. The screens will be performed in the presence of suppressive molecules to mimic the TME and are expected to uncover many key genes in DCs biology. We will develop a new strategy to find synergistic combinations of genes to target (named Perturb-comb), thereby reversing the effect of local tumor immunosuppressive signals. Lastly, we will examine the effect of modified DCs on T cell activation and proliferation in-vivo, and on tumor growth.
We expect to find: (1) Signaling molecules in the TME that affect the immune system. (2) New cytokines and cell surface receptors that are expressed in DCs and signal to T cells. (3) New key regulators in DC biology and their mechanisms. (4) Combinations of genes to target in DCs that reverse the TME’s hazardous effects.
Max ERC Funding
1 500 000 €
Duration
Start date: 2018-01-01, End date: 2022-12-31
Project acronym DecodingInfection
Project Decoding the host-pathogen interspecies crosstalk at a multiparametric single-cell level
Researcher (PI) Roi AVRAHAM
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Starting Grant (StG), LS6, ERC-2017-STG
Summary Bacterial pathogens remain a significant threat to global health, necessitating a better understanding of host-pathogen biology. While various evidence point to early infection as a key event in the eventual progression to disease, our recent preliminary data show that during this stage, highly adaptable and dynamic host cells and bacteria engage in complex, diverse interactions that contribute to well-documented heterogeneous outcomes of infection. However, current methodologies rely on measurements of bulk populations, thereby overlooking this diversity that can trigger different outcomes. This application focuses on understanding heterogeneity during the first stages of infection in order to reduce the complexity of these interactions into informative readouts of population physiology and predictors of infection outcome. We will apply multiparametric single-cell analysis to obtain an accurate and complete description of infection with the enteric intracellular pathogen Salmonella of macrophages in vitro, and in early stages of mice colonization. We will characterize the molecular details that underlie distinct infection outcomes of individual encounters, to reconstruct the repertoire of host and pathogen strategies that prevail at critical stages of early infection.
We propose the following three objectives: (1) Develop methodologies to simultaneously profile host and pathogen transcriptional changes on a single cell level; 2) Characterizing the molecular details that underlie the formation of subpopulations during macrophage infection; and (3) Determine how host and pathogen encounters in vivo result in emergence of specialized subpopulations, recruitment of immune cells and pathogen dissemination.
We anticipate that this work will fundamentally shift our paradigms of infectious disease pathogenesis and lay the groundwork for the development of a new generation of therapeutic agents targeting the specific host-pathogen interactions ultimately driving disease.
Summary
Bacterial pathogens remain a significant threat to global health, necessitating a better understanding of host-pathogen biology. While various evidence point to early infection as a key event in the eventual progression to disease, our recent preliminary data show that during this stage, highly adaptable and dynamic host cells and bacteria engage in complex, diverse interactions that contribute to well-documented heterogeneous outcomes of infection. However, current methodologies rely on measurements of bulk populations, thereby overlooking this diversity that can trigger different outcomes. This application focuses on understanding heterogeneity during the first stages of infection in order to reduce the complexity of these interactions into informative readouts of population physiology and predictors of infection outcome. We will apply multiparametric single-cell analysis to obtain an accurate and complete description of infection with the enteric intracellular pathogen Salmonella of macrophages in vitro, and in early stages of mice colonization. We will characterize the molecular details that underlie distinct infection outcomes of individual encounters, to reconstruct the repertoire of host and pathogen strategies that prevail at critical stages of early infection.
We propose the following three objectives: (1) Develop methodologies to simultaneously profile host and pathogen transcriptional changes on a single cell level; 2) Characterizing the molecular details that underlie the formation of subpopulations during macrophage infection; and (3) Determine how host and pathogen encounters in vivo result in emergence of specialized subpopulations, recruitment of immune cells and pathogen dissemination.
We anticipate that this work will fundamentally shift our paradigms of infectious disease pathogenesis and lay the groundwork for the development of a new generation of therapeutic agents targeting the specific host-pathogen interactions ultimately driving disease.
Max ERC Funding
1 499 999 €
Duration
Start date: 2017-10-01, End date: 2022-09-30
Project acronym FAT NKT
Project Targeting iNKT cell and adipocyte crosstalk for control of metabolism and body weight
Researcher (PI) Lydia Lynch
Host Institution (HI) THE PROVOST, FELLOWS, FOUNDATION SCHOLARS & THE OTHER MEMBERS OF BOARD OF THE COLLEGE OF THE HOLY & UNDIVIDED TRINITY OF QUEEN ELIZABETH NEAR DUBLIN
Call Details Starting Grant (StG), LS6, ERC-2015-STG
Summary Obesity has reached epidemic proportions globally. At least 2.8 million people die each year as a result of being overweight or obese, the biggest burden being obesity-related diseases. It is now clear that inflammation is an underlying cause or contributor to many of these diseases, including type 2 diabetes, atherosclerosis, and cancer. Recognition that the immune system can regulate metabolic pathways has prompted a new way of thinking about diabetes and weight management. Despite much recent progress, most immunometabolic pathways, and how to target them, are currently unknown. One such pathway is the cross-talk between invariant natural killer (iNKT) cells and neighboring adipocytes. iNKT cells are the innate lipid-sensing arm of the immune system. Since our discovery that mammalian adipose tissue is enriched for iNKT cells, we have identified a critical role for iNKT cells in regulating adipose inflammation and body weight. The goal of this project is to use a multi-disciplinary approach to identify key signals and molecules used by iNKT cells to induce metabolic control and weight loss in obesity. Using immunological assays and multi-photon intravital microscopy, cells and pathways that control the unique regulatory functions of adipose iNKT cells will be identified and characterised. Novel lipid antigens in adipose tissue will be identified using a biochemical approach, perhaps explaining iNKT cell conservation in adipose depots, and providing safe tools for iNKT cell manipulation in vivo. Finally, using proteomics and whole body metabolic analysis in vivo, novel ‘weight-loss inducing’ factors produced by adipose iNKT cells will be identified. This ambitious and high impact project has the potential to yield major insights into immunometabolic interactions at steady state and in obesity. The ability to activate or induce adipose iNKT cells holds remarkable potential as an entirely new therapeutic direction for treating obesity and type 2 diabetes.
Summary
Obesity has reached epidemic proportions globally. At least 2.8 million people die each year as a result of being overweight or obese, the biggest burden being obesity-related diseases. It is now clear that inflammation is an underlying cause or contributor to many of these diseases, including type 2 diabetes, atherosclerosis, and cancer. Recognition that the immune system can regulate metabolic pathways has prompted a new way of thinking about diabetes and weight management. Despite much recent progress, most immunometabolic pathways, and how to target them, are currently unknown. One such pathway is the cross-talk between invariant natural killer (iNKT) cells and neighboring adipocytes. iNKT cells are the innate lipid-sensing arm of the immune system. Since our discovery that mammalian adipose tissue is enriched for iNKT cells, we have identified a critical role for iNKT cells in regulating adipose inflammation and body weight. The goal of this project is to use a multi-disciplinary approach to identify key signals and molecules used by iNKT cells to induce metabolic control and weight loss in obesity. Using immunological assays and multi-photon intravital microscopy, cells and pathways that control the unique regulatory functions of adipose iNKT cells will be identified and characterised. Novel lipid antigens in adipose tissue will be identified using a biochemical approach, perhaps explaining iNKT cell conservation in adipose depots, and providing safe tools for iNKT cell manipulation in vivo. Finally, using proteomics and whole body metabolic analysis in vivo, novel ‘weight-loss inducing’ factors produced by adipose iNKT cells will be identified. This ambitious and high impact project has the potential to yield major insights into immunometabolic interactions at steady state and in obesity. The ability to activate or induce adipose iNKT cells holds remarkable potential as an entirely new therapeutic direction for treating obesity and type 2 diabetes.
Max ERC Funding
1 804 052 €
Duration
Start date: 2016-09-01, End date: 2021-08-31
Project acronym GutBCells
Project Cellular Dynamics of Intestinal Antibody-Mediated Immune Response
Researcher (PI) Ziv Shulman Ben-Avraham
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE LTD
Call Details Starting Grant (StG), LS6, ERC-2015-STG
Summary Vaccination is widely used to prevent human diseases by inducing the formation of cellular and antibody-mediated immune responses for induction of long lasting immunological memory. Although most studies focus on immune responses elicited against injected immunizations, the simplest delivery of a vaccine regimen is by oral administration. The cellular and molecular components of the antibody immune response in peripheral lymph nodes in response to immunization are well described, however, much less is known about the dynamics of immune cells in gut associate lymphoid tissues (GALT) and adjust intestinal mucosal tissues. In the proposed research plan I will implicate intravital in vivo imaging for analysis of the cellular component of the antibody immune response in intestinal tissues. My goals are: 1. To track germinal center (GC) T cells for prolong time periods in peripheral lymph nodes and GALT and determine if they enter the memory compartment. For this purpose I will develop a new photoactivation method for permanently labeling immune cells and fate tracing of their daughter cells. 2. To examine T-B interactions and their regulation by intraceullar signaling pathways in GALT and to determine where and when class switch recombination to IgA takes place. For this purpose I will use intravital imaging of fluorescent reporter mice. 3. I will analyze the dynamics of plasma cell migration from Peyer’s patches to the mucosa by implementing state of the art photoactivation and imaging techniques that allow prolonged cell tracking. I will also use photoactivation approaches for sorting plasma cells from specific intestinal layers and perform gene expression analysis. 4. I will develop a new method to study dynamics and fate of B cells specific for commensal microbes in the GC, memory and plasma cell compartments. This research plan will extend our knowledge of the antibody immune response in intestinal tissues towards the future design of improved oral vaccinations.
Summary
Vaccination is widely used to prevent human diseases by inducing the formation of cellular and antibody-mediated immune responses for induction of long lasting immunological memory. Although most studies focus on immune responses elicited against injected immunizations, the simplest delivery of a vaccine regimen is by oral administration. The cellular and molecular components of the antibody immune response in peripheral lymph nodes in response to immunization are well described, however, much less is known about the dynamics of immune cells in gut associate lymphoid tissues (GALT) and adjust intestinal mucosal tissues. In the proposed research plan I will implicate intravital in vivo imaging for analysis of the cellular component of the antibody immune response in intestinal tissues. My goals are: 1. To track germinal center (GC) T cells for prolong time periods in peripheral lymph nodes and GALT and determine if they enter the memory compartment. For this purpose I will develop a new photoactivation method for permanently labeling immune cells and fate tracing of their daughter cells. 2. To examine T-B interactions and their regulation by intraceullar signaling pathways in GALT and to determine where and when class switch recombination to IgA takes place. For this purpose I will use intravital imaging of fluorescent reporter mice. 3. I will analyze the dynamics of plasma cell migration from Peyer’s patches to the mucosa by implementing state of the art photoactivation and imaging techniques that allow prolonged cell tracking. I will also use photoactivation approaches for sorting plasma cells from specific intestinal layers and perform gene expression analysis. 4. I will develop a new method to study dynamics and fate of B cells specific for commensal microbes in the GC, memory and plasma cell compartments. This research plan will extend our knowledge of the antibody immune response in intestinal tissues towards the future design of improved oral vaccinations.
Max ERC Funding
1 375 000 €
Duration
Start date: 2016-05-01, End date: 2021-04-30
Project acronym LIVERMIRCOENV
Project Heterotypic Cell Interactions in Hepatitis induced Liver Cancer
Researcher (PI) Eli Pikarsky
Host Institution (HI) THE HEBREW UNIVERSITY OF JERUSALEM
Call Details Starting Grant (StG), LS6, ERC-2011-StG_20101109
Summary The link between inflammation and cancer is now established, yet the underlying molecular mechanisms are unresolved. As tumors progress, they modulate inflammatory cells towards a pro-tumorigenic phenotype. We have shown that inflammatory cells reciprocate by sculpting the parenchymal epithelial cells. I hypothesize that these reciprocal interactions lie at the heart of the link between inflammation and cancer.
Hepatocellular carcinoma (HCC), one of the deadliest tumors, is a prototype of inflammation induced cancer. My team will employ a twofold strategy to analyze the changes occuring in inflammatory cells before and after tumors emerge, based on preliminary findings showing that changes in inflammatory cells precede tumorigenesis. First, we will perform comprehensive mapping of the changing inflammatory microenvironment in a mouse model of inflammation induced HCC. We will employ genetic manipulation strategies, coupled to cell isolation techniques to delineate the molecular cues that mediate these changes and then will analyze the functional role of key mediators of these processes in HCC. Microfluidics approaches will give us a highthroughput quantitative view of these heterotypic interactions. The same approaches will be harnessed to identify the interactions that form the liver stem cell niche which dramatically expands in states of chronic inflammation. Second, drawing on our finding that a recurring tumor amplicon drives HCC progression by modulating the microenvironment, we will work towards identifying additional similar amplicons to define additional key effectors of the microenvironment.
Of special importance, heterotypic cell interactions that play key roles in both cancer initiation and progression, present ideal therapeutic targets, which are easily accessible and less amenable to mutational selection. Furthermore, the results of our experiments could also have far reaching implications in other inflammatory states and different types of cancer.
Summary
The link between inflammation and cancer is now established, yet the underlying molecular mechanisms are unresolved. As tumors progress, they modulate inflammatory cells towards a pro-tumorigenic phenotype. We have shown that inflammatory cells reciprocate by sculpting the parenchymal epithelial cells. I hypothesize that these reciprocal interactions lie at the heart of the link between inflammation and cancer.
Hepatocellular carcinoma (HCC), one of the deadliest tumors, is a prototype of inflammation induced cancer. My team will employ a twofold strategy to analyze the changes occuring in inflammatory cells before and after tumors emerge, based on preliminary findings showing that changes in inflammatory cells precede tumorigenesis. First, we will perform comprehensive mapping of the changing inflammatory microenvironment in a mouse model of inflammation induced HCC. We will employ genetic manipulation strategies, coupled to cell isolation techniques to delineate the molecular cues that mediate these changes and then will analyze the functional role of key mediators of these processes in HCC. Microfluidics approaches will give us a highthroughput quantitative view of these heterotypic interactions. The same approaches will be harnessed to identify the interactions that form the liver stem cell niche which dramatically expands in states of chronic inflammation. Second, drawing on our finding that a recurring tumor amplicon drives HCC progression by modulating the microenvironment, we will work towards identifying additional similar amplicons to define additional key effectors of the microenvironment.
Of special importance, heterotypic cell interactions that play key roles in both cancer initiation and progression, present ideal therapeutic targets, which are easily accessible and less amenable to mutational selection. Furthermore, the results of our experiments could also have far reaching implications in other inflammatory states and different types of cancer.
Max ERC Funding
1 499 940 €
Duration
Start date: 2011-10-01, End date: 2017-09-30
Project acronym MalPar.NET
Project Malaria Parasite Networking: Discovering Modes of Cell-Cell Communication
Researcher (PI) Neta REGEV-RUDZKI
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Starting Grant (StG), LS6, ERC-2017-STG
Summary Malaria, caused by Plasmodium falciparum, is a devastating parasitic disease effecting hundreds of millions of people worldwide. The parasite’s transmission cycle between humans and mosquitoes involves a remarkable series of morphological transformations. While it is clear that, for such a complex journey, the parasites must develop means to sense their host and coordinate their actions; these modes of communication remain one of the greatest mysteries in malaria biology. In fact, since an individual parasite is enclosed by three membranes inside its human host, the red blood cell (RBC), they were not thought to possess any communication ability. However, we discovered that these parasites, despite the multiple barriers, are able to communicate and exchange episomal genes by releasing exosome-like vesicles, thereby opening the exciting new field of malaria parasite communication. Our initial data demonstrate that these vesicles serve as a secure tool for the delivery of remarkable components.
The overarching goal of this proposal is to take an innovative look at this under-investigated area of parasite sensing and signalling pathways and to decipher the multiple layers of parasite and host signalling networks. Specifically, we will determine the biological roles of Plasmodium exosome cargo components in: parasite-parasite communication - exploring parasite coordination traits in cell-density growth and sexual development (Objective 1); and parasite-host communication - unravelling the mutual communication of the parasite and its hosts, the red blood and immune cells (Objective 2). Simultaneously, we will exploit our experience in cell communication research to investigate the complementary, yet-to-be-explored mode of parasite communication via the secretion of small molecules (Objective 3).
Our project will provide a holistic view of parasite communication networking while potentially providing, in the long term, novel targets for malaria therapeutics.
Summary
Malaria, caused by Plasmodium falciparum, is a devastating parasitic disease effecting hundreds of millions of people worldwide. The parasite’s transmission cycle between humans and mosquitoes involves a remarkable series of morphological transformations. While it is clear that, for such a complex journey, the parasites must develop means to sense their host and coordinate their actions; these modes of communication remain one of the greatest mysteries in malaria biology. In fact, since an individual parasite is enclosed by three membranes inside its human host, the red blood cell (RBC), they were not thought to possess any communication ability. However, we discovered that these parasites, despite the multiple barriers, are able to communicate and exchange episomal genes by releasing exosome-like vesicles, thereby opening the exciting new field of malaria parasite communication. Our initial data demonstrate that these vesicles serve as a secure tool for the delivery of remarkable components.
The overarching goal of this proposal is to take an innovative look at this under-investigated area of parasite sensing and signalling pathways and to decipher the multiple layers of parasite and host signalling networks. Specifically, we will determine the biological roles of Plasmodium exosome cargo components in: parasite-parasite communication - exploring parasite coordination traits in cell-density growth and sexual development (Objective 1); and parasite-host communication - unravelling the mutual communication of the parasite and its hosts, the red blood and immune cells (Objective 2). Simultaneously, we will exploit our experience in cell communication research to investigate the complementary, yet-to-be-explored mode of parasite communication via the secretion of small molecules (Objective 3).
Our project will provide a holistic view of parasite communication networking while potentially providing, in the long term, novel targets for malaria therapeutics.
Max ERC Funding
1 500 000 €
Duration
Start date: 2017-10-01, End date: 2022-09-30
Project acronym MIX-Effectors
Project T6SS MIX-effectors: secretion, activities and use as antibacterial treatment
Researcher (PI) Dor Samuel Salomon
Host Institution (HI) TEL AVIV UNIVERSITY
Call Details Starting Grant (StG), LS6, ERC-2016-STG
Summary Bacteria use various mechanisms to combat competitors and colonize new niches. The Type VI Secretion System (T6SS), a contact-dependent protein delivery apparatus, is a widespread, recently discovered machine used by Gram-negative bacteria to target competitors. Its toxicity is mediated by secreted proteins called effectors, yet the identity of many effectors, the mechanism of secretion of different effector classes, and their toxic activities remain largely unknown. I recently uncovered a widespread class of T6SS effectors that share a domain called MIX. MIX-effectors are polymorphic proteins carrying various toxin domains, many of which with unknown activities.
Many bacterial pathogens have acquired resistance to contemporary antibiotic treatments, becoming a public health threat and necessitating the development of novel antibacterial strategies. Thus, as a relatively untapped antibacterial system, studying the T6SS and its MIX-effectors presents a double incentive: 1) previously uncharacterized antibacterial activities of MIX-effectors can illuminate novel cellular targets for antibacterial drug development; 2) the T6SS machinery can be used as a novel toxin delivery platform to combat multi-drug resistant bacterial infections, using polymorphic MIX-effectors.
In this proposal, I will focus on T6SS MIX-effectors and elucidate their activities, mechanism of secretion, and utilization as antibacterial agents, by combining microbiology, molecular biology, genetic, biochemical, and proteomic approaches. Specifically, the goal of this proposal is to utilize T6SSs and MIX-effectors to develop a novel T6SS-based, antibacterial therapeutic platform in which a nonpathogenic bacterium will be engineered to carry a T6SS that can secrete a diverse repertoire of polymorphic antibacterial MIX-effectors. This innovative platform has several advantages over current antibacterial strategies, and can be used as an adjustable tool to combat multi-drug resistant bacteria.
Summary
Bacteria use various mechanisms to combat competitors and colonize new niches. The Type VI Secretion System (T6SS), a contact-dependent protein delivery apparatus, is a widespread, recently discovered machine used by Gram-negative bacteria to target competitors. Its toxicity is mediated by secreted proteins called effectors, yet the identity of many effectors, the mechanism of secretion of different effector classes, and their toxic activities remain largely unknown. I recently uncovered a widespread class of T6SS effectors that share a domain called MIX. MIX-effectors are polymorphic proteins carrying various toxin domains, many of which with unknown activities.
Many bacterial pathogens have acquired resistance to contemporary antibiotic treatments, becoming a public health threat and necessitating the development of novel antibacterial strategies. Thus, as a relatively untapped antibacterial system, studying the T6SS and its MIX-effectors presents a double incentive: 1) previously uncharacterized antibacterial activities of MIX-effectors can illuminate novel cellular targets for antibacterial drug development; 2) the T6SS machinery can be used as a novel toxin delivery platform to combat multi-drug resistant bacterial infections, using polymorphic MIX-effectors.
In this proposal, I will focus on T6SS MIX-effectors and elucidate their activities, mechanism of secretion, and utilization as antibacterial agents, by combining microbiology, molecular biology, genetic, biochemical, and proteomic approaches. Specifically, the goal of this proposal is to utilize T6SSs and MIX-effectors to develop a novel T6SS-based, antibacterial therapeutic platform in which a nonpathogenic bacterium will be engineered to carry a T6SS that can secrete a diverse repertoire of polymorphic antibacterial MIX-effectors. This innovative platform has several advantages over current antibacterial strategies, and can be used as an adjustable tool to combat multi-drug resistant bacteria.
Max ERC Funding
1 484 375 €
Duration
Start date: 2017-02-01, End date: 2022-01-31
Project acronym PathoPhageHost
Project Studying Pathogen Phage Host Interactions
Researcher (PI) Anat Herskovits
Host Institution (HI) TEL AVIV UNIVERSITY
Call Details Starting Grant (StG), LS6, ERC-2013-StG
Summary The DNA uptake competence system of the intracellular bacterial pathogen Listeria monocytogenes was considered non-functional. There are no known conditions for DNA transformation and the competence master activator gene, comK, is interrupted by a temperate (lysogenic) prophage. We have shown recently that the L. monocytogenes competence system is required during infection to promote bacterial escape from macrophage phagosomes, in a manner that is independent of DNA uptake. Remarkably, we found that regulation of the competence system relies on the formation of a functional comK gene via a controlled process of prophage excision. Prophage excision was specifically induced during intracellular growth, primarily within phagosomes, yet, unlike classic prophage induction, progeny virions were not produced and bacterial lysis did not occur. This study revealed a unique adaptation of a prophage to the intracellular life style of its host, whereby the prophage serves as a genetic switch to modulate the virulence of its host. In the proposed project we aim to investigate this phenomenon and study the give-and-take interactions between the L. monocytogenes 10403S strain and its ϕ10403S-prophage during mammalian infection. We will study the prophage determinants and mechanisms that control intracellular excision and maintenance as well as the mechanisms that prevent its virions production and bacterial lysis. We will explore the crosstalk between phage and bacterial regulatory factors and characterize the mammalian host signals/conditions that trigger this unique prophage response. Lastly, we will investigate the unexpected function of the competence system in phagosomal escape. In particular, we will explore the possibility that the competence system serves as an auxiliary secretion system, which secretes proteins that promote phagosomal escape.
Summary
The DNA uptake competence system of the intracellular bacterial pathogen Listeria monocytogenes was considered non-functional. There are no known conditions for DNA transformation and the competence master activator gene, comK, is interrupted by a temperate (lysogenic) prophage. We have shown recently that the L. monocytogenes competence system is required during infection to promote bacterial escape from macrophage phagosomes, in a manner that is independent of DNA uptake. Remarkably, we found that regulation of the competence system relies on the formation of a functional comK gene via a controlled process of prophage excision. Prophage excision was specifically induced during intracellular growth, primarily within phagosomes, yet, unlike classic prophage induction, progeny virions were not produced and bacterial lysis did not occur. This study revealed a unique adaptation of a prophage to the intracellular life style of its host, whereby the prophage serves as a genetic switch to modulate the virulence of its host. In the proposed project we aim to investigate this phenomenon and study the give-and-take interactions between the L. monocytogenes 10403S strain and its ϕ10403S-prophage during mammalian infection. We will study the prophage determinants and mechanisms that control intracellular excision and maintenance as well as the mechanisms that prevent its virions production and bacterial lysis. We will explore the crosstalk between phage and bacterial regulatory factors and characterize the mammalian host signals/conditions that trigger this unique prophage response. Lastly, we will investigate the unexpected function of the competence system in phagosomal escape. In particular, we will explore the possibility that the competence system serves as an auxiliary secretion system, which secretes proteins that promote phagosomal escape.
Max ERC Funding
1 490 400 €
Duration
Start date: 2013-10-01, End date: 2018-09-30
Project acronym Profile Infection
Project Unraveling changes in cellular gene expression during viral infection
Researcher (PI) Noam Stern-Ginossar
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Starting Grant (StG), LS6, ERC-2014-STG
Summary The herpesvirus human cytomegalovirus (HCMV) infects the majority of the world's population, leading to severe diseases in millions of newborns and immunocompromised adults annually. During infection, HCMV extensively manipulates cellular gene expression to maintain conditions favorable for efficient viral propagation. Identifying the pathways that the virus relies on or subverts is of great interest as they have the potential to provide new therapeutic windows and reveal novel principles in cell biology. Over the past years high-throughput analyses have profoundly broadened our understanding of the processes that occur during HCMV infection. However, much of this analysis is focused on transcriptional changes at the lytic phase of infection leaving posttranscriptional regulation and the latent phase of the virus relatively untouched. Novel emerging technologies have the potential to extend our knowledge in areas that were heretofore unattainable.
My overall goal is to decipher the multiple mechanisms by which HCMV modulates the host cell. For this, I will use multiple cutting-edge deep-sequencing and imaging technologies that will allow the analysis of novel aspects of host gene regulation during infection. Accordingly, the primary objectives of this research proposal are: 1) Deciphering posttranscriptional mechanisms that control cellular gene expression during HCMV infection; 2) Identifying and characterizing cellular protein diversification during infection; and 3) Uncovering the changes that occur in infected cells during latent infection. The knowledge generated from these objectives will provide us with a clearer depiction of the changes that take place during HCMV infection, which in turn can facilitate the development of novel anti-viral strategies. More broadly, with its comprehensive and complementarity approaches, this work will provide a paradigm for understanding how gene expression is regulated during a complex biological process.
Summary
The herpesvirus human cytomegalovirus (HCMV) infects the majority of the world's population, leading to severe diseases in millions of newborns and immunocompromised adults annually. During infection, HCMV extensively manipulates cellular gene expression to maintain conditions favorable for efficient viral propagation. Identifying the pathways that the virus relies on or subverts is of great interest as they have the potential to provide new therapeutic windows and reveal novel principles in cell biology. Over the past years high-throughput analyses have profoundly broadened our understanding of the processes that occur during HCMV infection. However, much of this analysis is focused on transcriptional changes at the lytic phase of infection leaving posttranscriptional regulation and the latent phase of the virus relatively untouched. Novel emerging technologies have the potential to extend our knowledge in areas that were heretofore unattainable.
My overall goal is to decipher the multiple mechanisms by which HCMV modulates the host cell. For this, I will use multiple cutting-edge deep-sequencing and imaging technologies that will allow the analysis of novel aspects of host gene regulation during infection. Accordingly, the primary objectives of this research proposal are: 1) Deciphering posttranscriptional mechanisms that control cellular gene expression during HCMV infection; 2) Identifying and characterizing cellular protein diversification during infection; and 3) Uncovering the changes that occur in infected cells during latent infection. The knowledge generated from these objectives will provide us with a clearer depiction of the changes that take place during HCMV infection, which in turn can facilitate the development of novel anti-viral strategies. More broadly, with its comprehensive and complementarity approaches, this work will provide a paradigm for understanding how gene expression is regulated during a complex biological process.
Max ERC Funding
1 500 000 €
Duration
Start date: 2015-06-01, End date: 2020-05-31
