Project acronym AEROBIC
Project Assessing the Effects of Rising O2 on Biogeochemical Cycles: Integrated Laboratory Experiments and Numerical Simulations
Researcher (PI) Itay Halevy
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Starting Grant (StG), PE10, ERC-2013-StG
Summary The rise of atmospheric O2 ~2,500 million years ago is one of the most profound transitions in Earth's history. Yet, despite its central role in shaping Earth's surface environment, the cause for the rise of O2 remains poorly understood. Tight coupling between the O2 cycle and the biogeochemical cycles of redox-active elements, such as C, Fe and S, implies radical changes in these cycles before, during and after the rise of O2. These changes, too, are incompletely understood, but have left valuable information encoded in the geological record. This information has been qualitatively interpreted, leaving many aspects of the rise of O2, including its causes and constraints on ocean chemistry before and after it, topics of ongoing research and debate. Here, I outline a research program to address this fundamental question in geochemical Earth systems evolution. The inherently interdisciplinary program uniquely integrates laboratory experiments, numerical models, geological observations, and geochemical analyses. Laboratory experiments and geological observations will constrain unknown parameters of the early biogeochemical cycles, and, in combination with field studies, will validate and refine the use of paleoenvironmental proxies. The insight gained will be used to develop detailed models of the coupled biogeochemical cycles, which will themselves be used to quantitatively understand the events surrounding the rise of O2, and to illuminate the dynamics of elemental cycles in the early oceans.
This program is expected to yield novel, quantitative insight into these important events in Earth history and to have a major impact on our understanding of early ocean chemistry and the rise of O2. An ERC Starting Grant will enable me to use the excellent experimental and computational facilities at my disposal, to access the outstanding human resource at the Weizmann Institute of Science, and to address one of the major open questions in modern geochemistry.
Summary
The rise of atmospheric O2 ~2,500 million years ago is one of the most profound transitions in Earth's history. Yet, despite its central role in shaping Earth's surface environment, the cause for the rise of O2 remains poorly understood. Tight coupling between the O2 cycle and the biogeochemical cycles of redox-active elements, such as C, Fe and S, implies radical changes in these cycles before, during and after the rise of O2. These changes, too, are incompletely understood, but have left valuable information encoded in the geological record. This information has been qualitatively interpreted, leaving many aspects of the rise of O2, including its causes and constraints on ocean chemistry before and after it, topics of ongoing research and debate. Here, I outline a research program to address this fundamental question in geochemical Earth systems evolution. The inherently interdisciplinary program uniquely integrates laboratory experiments, numerical models, geological observations, and geochemical analyses. Laboratory experiments and geological observations will constrain unknown parameters of the early biogeochemical cycles, and, in combination with field studies, will validate and refine the use of paleoenvironmental proxies. The insight gained will be used to develop detailed models of the coupled biogeochemical cycles, which will themselves be used to quantitatively understand the events surrounding the rise of O2, and to illuminate the dynamics of elemental cycles in the early oceans.
This program is expected to yield novel, quantitative insight into these important events in Earth history and to have a major impact on our understanding of early ocean chemistry and the rise of O2. An ERC Starting Grant will enable me to use the excellent experimental and computational facilities at my disposal, to access the outstanding human resource at the Weizmann Institute of Science, and to address one of the major open questions in modern geochemistry.
Max ERC Funding
1 472 690 €
Duration
Start date: 2013-09-01, End date: 2018-08-31
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 FORECASToneMONTH
Project Forecasting Surface Weather and Climate at One-Month Leads through Stratosphere-Troposphere Coupling
Researcher (PI) Chaim Israel Garfinkel
Host Institution (HI) THE HEBREW UNIVERSITY OF JERUSALEM
Call Details Starting Grant (StG), PE10, ERC-2015-STG
Summary Anomalies in surface temperatures, winds, and precipitation can significantly alter energy supply and demand, cause flooding, and cripple transportation networks. Better management of these impacts can be achieved by extending the duration of reliable predictions of the atmospheric circulation.
Polar stratospheric variability can impact surface weather for well over a month, and this proposed research presents a novel approach towards understanding the fundamentals of how this coupling occurs. Specifically, we are interested in: 1) how predictable are anomalies in the stratospheric circulation? 2) why do only some stratospheric events modify surface weather? and 3) what is the mechanism whereby stratospheric anomalies reach the surface? While this last question may appear academic, several studies indicate that stratosphere-troposphere coupling drives the midlatitude tropospheric response to climate change; therefore, a clearer understanding of the mechanisms will aid in the interpretation of the upcoming changes in the surface climate.
I propose a multi-pronged effort aimed at addressing these questions and improving monthly forecasting. First, carefully designed modelling experiments using a novel modelling framework will be used to clarify how, and under what conditions, stratospheric variability couples to tropospheric variability. Second, novel linkages between variability external to the stratospheric polar vortex and the stratospheric polar vortex will be pursued, thus improving our ability to forecast polar vortex variability itself. To these ends, my group will develop 1) an analytic model for Rossby wave propagation on the sphere, and 2) a simplified general circulation model, which captures the essential processes underlying stratosphere-troposphere coupling. By combining output from the new models, observational data, and output from comprehensive climate models, the connections between the stratosphere and surface climate will be elucidated.
Summary
Anomalies in surface temperatures, winds, and precipitation can significantly alter energy supply and demand, cause flooding, and cripple transportation networks. Better management of these impacts can be achieved by extending the duration of reliable predictions of the atmospheric circulation.
Polar stratospheric variability can impact surface weather for well over a month, and this proposed research presents a novel approach towards understanding the fundamentals of how this coupling occurs. Specifically, we are interested in: 1) how predictable are anomalies in the stratospheric circulation? 2) why do only some stratospheric events modify surface weather? and 3) what is the mechanism whereby stratospheric anomalies reach the surface? While this last question may appear academic, several studies indicate that stratosphere-troposphere coupling drives the midlatitude tropospheric response to climate change; therefore, a clearer understanding of the mechanisms will aid in the interpretation of the upcoming changes in the surface climate.
I propose a multi-pronged effort aimed at addressing these questions and improving monthly forecasting. First, carefully designed modelling experiments using a novel modelling framework will be used to clarify how, and under what conditions, stratospheric variability couples to tropospheric variability. Second, novel linkages between variability external to the stratospheric polar vortex and the stratospheric polar vortex will be pursued, thus improving our ability to forecast polar vortex variability itself. To these ends, my group will develop 1) an analytic model for Rossby wave propagation on the sphere, and 2) a simplified general circulation model, which captures the essential processes underlying stratosphere-troposphere coupling. By combining output from the new models, observational data, and output from comprehensive climate models, the connections between the stratosphere and surface climate will be elucidated.
Max ERC Funding
1 808 000 €
Duration
Start date: 2016-05-01, End date: 2021-04-30
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 OOID
Project The Ocean's Oxygen Isotopes Deciphered: Combining Observations, Experiments and Models
Researcher (PI) Itay HALEVY
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Starting Grant (StG), PE10, ERC-2017-STG
Summary The isotopic composition of O in seawater is a fundamental property of Earth's oceans, key to paleoclimate reconstructions and to our understanding of the origin of water on Earth, the water-rock reactions that govern seawater chemistry, and the conditions under which life emerged. Despite more than five decades of research, the geologic history of seawater 18O/16O remains a topic of intense debate. Without exception, well-preserved 18O/16O records from marine precipitates reflect both the minerals' formation temperature, and the isotopic composition of seawater. This duality has prevented unique interpretation of a long-term secular trend, in which 18O/16O in sedimentary rocks (e.g., carbonates, cherts) has increased by ~15 ‰ since the Archean. Here I outline an inter-disciplinary research program to address this fundamental problem, which integrates new geochemical observations, laboratory experiments, and numerical models.
We will generate geologic records of 18O/16O in two previously untapped repositories: iron oxides and iron-bearing authigenic clays. Several characteristics of both, and preliminary results, suggest that these repositories hold the potential to settle the long-standing debate about seawater 18O/16O. We will determine the temperature dependence of mineral-water O isotope fractionation in laboratory experiments and observations of natural systems. We will experimentally test the resistance of these minerals to O isotope exchange under geologically-relevant conditions, with the aim of evaluating the potential for late-stage isotopic resetting. Finally, we will develop models of the marine O isotope cycle, which account for the processes that govern seawater 18O/16O over long timescales, and which will be used to provide a quantitative understanding of the new records. With these new insights, we will explore implications for the geologic history of seawater chemistry, atmospheric composition, climate and biology.
Summary
The isotopic composition of O in seawater is a fundamental property of Earth's oceans, key to paleoclimate reconstructions and to our understanding of the origin of water on Earth, the water-rock reactions that govern seawater chemistry, and the conditions under which life emerged. Despite more than five decades of research, the geologic history of seawater 18O/16O remains a topic of intense debate. Without exception, well-preserved 18O/16O records from marine precipitates reflect both the minerals' formation temperature, and the isotopic composition of seawater. This duality has prevented unique interpretation of a long-term secular trend, in which 18O/16O in sedimentary rocks (e.g., carbonates, cherts) has increased by ~15 ‰ since the Archean. Here I outline an inter-disciplinary research program to address this fundamental problem, which integrates new geochemical observations, laboratory experiments, and numerical models.
We will generate geologic records of 18O/16O in two previously untapped repositories: iron oxides and iron-bearing authigenic clays. Several characteristics of both, and preliminary results, suggest that these repositories hold the potential to settle the long-standing debate about seawater 18O/16O. We will determine the temperature dependence of mineral-water O isotope fractionation in laboratory experiments and observations of natural systems. We will experimentally test the resistance of these minerals to O isotope exchange under geologically-relevant conditions, with the aim of evaluating the potential for late-stage isotopic resetting. Finally, we will develop models of the marine O isotope cycle, which account for the processes that govern seawater 18O/16O over long timescales, and which will be used to provide a quantitative understanding of the new records. With these new insights, we will explore implications for the geologic history of seawater chemistry, atmospheric composition, climate and biology.
Max ERC Funding
1 490 596 €
Duration
Start date: 2018-09-01, End date: 2023-08-31
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
