Project acronym A-FRO
Project Actively Frozen - contextual modulation of freezing and its neuronal basis
Researcher (PI) Marta de Aragão Pacheco Moita
Host Institution (HI) FUNDACAO D. ANNA SOMMER CHAMPALIMAUD E DR. CARLOS MONTEZ CHAMPALIMAUD
Call Details Consolidator Grant (CoG), LS5, ERC-2018-COG
Summary When faced with a threat, an animal must decide whether to freeze, reducing its chances of being noticed, or to flee to the safety of a refuge. Animals from fish to primates choose between these two alternatives when confronted by an attacking predator, a choice that largely depends on the context in which the threat occurs. Recent work has made strides identifying the pre-motor circuits, and their inputs, which control freezing behavior in rodents, but how contextual information is integrated to guide this choice is still far from understood. We recently found that fruit flies in response to visual looming stimuli, simulating a large object on collision course, make rapid freeze/flee choices that depend on the social and spatial environment, and the fly’s internal state. Further, identification of looming detector neurons was recently reported and we identified the descending command neurons, DNp09, responsible for freezing in the fly. Knowing the sensory input and descending output for looming-evoked freezing, two environmental factors that modulate its expression, and using a genetically tractable system affording the use of large sample sizes, places us in an unique position to understand how a information about a threat is integrated with cues from the environment to guide the choice of whether to freeze (our goal). To assess how social information impinges on the circuit for freezing, we will examine the sensory inputs and neuromodulators that mediate this process, mapping their connections to DNp09 neurons (Aim 1). We ask whether learning is required for the spatial modulation of freezing, which cues flies are using to discriminate different places and which brain circuits mediate this process (Aim 2). Finally, we will study how activity of DNp09 neurons drives freezing (Aim 3). This project will provide a comprehensive understanding of the mechanism of freezing and its modulation by the environment, from single neurons to behaviour.
Summary
When faced with a threat, an animal must decide whether to freeze, reducing its chances of being noticed, or to flee to the safety of a refuge. Animals from fish to primates choose between these two alternatives when confronted by an attacking predator, a choice that largely depends on the context in which the threat occurs. Recent work has made strides identifying the pre-motor circuits, and their inputs, which control freezing behavior in rodents, but how contextual information is integrated to guide this choice is still far from understood. We recently found that fruit flies in response to visual looming stimuli, simulating a large object on collision course, make rapid freeze/flee choices that depend on the social and spatial environment, and the fly’s internal state. Further, identification of looming detector neurons was recently reported and we identified the descending command neurons, DNp09, responsible for freezing in the fly. Knowing the sensory input and descending output for looming-evoked freezing, two environmental factors that modulate its expression, and using a genetically tractable system affording the use of large sample sizes, places us in an unique position to understand how a information about a threat is integrated with cues from the environment to guide the choice of whether to freeze (our goal). To assess how social information impinges on the circuit for freezing, we will examine the sensory inputs and neuromodulators that mediate this process, mapping their connections to DNp09 neurons (Aim 1). We ask whether learning is required for the spatial modulation of freezing, which cues flies are using to discriminate different places and which brain circuits mediate this process (Aim 2). Finally, we will study how activity of DNp09 neurons drives freezing (Aim 3). This project will provide a comprehensive understanding of the mechanism of freezing and its modulation by the environment, from single neurons to behaviour.
Max ERC Funding
1 969 750 €
Duration
Start date: 2019-02-01, End date: 2024-01-31
Project acronym CELLFITNESS
Project Active Mechanisms of Cell Selection: From Cell Competition to Cell Fitness
Researcher (PI) Eduardo Moreno Lampaya
Host Institution (HI) FUNDACAO D. ANNA SOMMER CHAMPALIMAUD E DR. CARLOS MONTEZ CHAMPALIMAUD
Call Details Consolidator Grant (CoG), LS3, ERC-2013-CoG
Summary The molecular mechanisms that mediate cell competition, cell fitness and cell selection is gaining interest. With innovative approaches, molecules and ground-breaking hypothesis, this field of research can help understand several biological processes such as development, cancer and tissue degeneration. The project has 3 clear and ambitious objectives: 1. We propose to identify all the key genes mediating cell competition and their molecular mechanisms. In order to reach this objective we will use data from two whole genome screens in Drosophila where we have identified 7 key genes. By the end of this CoG grant, we should have no big gaps in our knowledge of how slow dividing cells are recognised and eliminated in Drosophila. 2. In addition, we will explore how general the cell competition pathways are and how they can impact biomedical research, with a focus in cancer and tissue degeneration. The interest in cancer is based on experiments in Drosophila and mice where we and others have found that an active process of cell selection determines tumour growth. Preliminary results suggest that the pathways identified do not only play important roles in the elimination of slow dividing cells, but also during cancer initiation and progression. 3. We will further explore the role of cell competition in neuronal selection, specially during neurodegeneration, development of the retina and adult brain regeneration in Drosophila. This proposal is of an interdisciplinary nature because it takes a basic cellular mechanism (the genetic pathways that select cells within tissues) and crosses boundaries between different fields of research: development, cancer, regeneration and tissue degeneration. In this ERC CoG proposal, we are committed to continue our efforts from basic science to biomedical approaches. The phenomena of cell competition and its participating genes have the potential to discover novel biomarkers and therapeutic strategies against cancer and tissue degeneration.
Summary
The molecular mechanisms that mediate cell competition, cell fitness and cell selection is gaining interest. With innovative approaches, molecules and ground-breaking hypothesis, this field of research can help understand several biological processes such as development, cancer and tissue degeneration. The project has 3 clear and ambitious objectives: 1. We propose to identify all the key genes mediating cell competition and their molecular mechanisms. In order to reach this objective we will use data from two whole genome screens in Drosophila where we have identified 7 key genes. By the end of this CoG grant, we should have no big gaps in our knowledge of how slow dividing cells are recognised and eliminated in Drosophila. 2. In addition, we will explore how general the cell competition pathways are and how they can impact biomedical research, with a focus in cancer and tissue degeneration. The interest in cancer is based on experiments in Drosophila and mice where we and others have found that an active process of cell selection determines tumour growth. Preliminary results suggest that the pathways identified do not only play important roles in the elimination of slow dividing cells, but also during cancer initiation and progression. 3. We will further explore the role of cell competition in neuronal selection, specially during neurodegeneration, development of the retina and adult brain regeneration in Drosophila. This proposal is of an interdisciplinary nature because it takes a basic cellular mechanism (the genetic pathways that select cells within tissues) and crosses boundaries between different fields of research: development, cancer, regeneration and tissue degeneration. In this ERC CoG proposal, we are committed to continue our efforts from basic science to biomedical approaches. The phenomena of cell competition and its participating genes have the potential to discover novel biomarkers and therapeutic strategies against cancer and tissue degeneration.
Max ERC Funding
1 968 062 €
Duration
Start date: 2014-06-01, End date: 2019-05-31
Project acronym CentrioleBirthDeath
Project Mechanism of centriole inheritance and maintenance
Researcher (PI) Monica BETTENCOURT CARVALHO DIAS
Host Institution (HI) FUNDACAO CALOUSTE GULBENKIAN
Call Details Consolidator Grant (CoG), LS3, ERC-2015-CoG
Summary Centrioles assemble centrosomes and cilia/flagella, critical structures for cell division, polarity, motility and signalling, which are often deregulated in human disease. Centriole inheritance, in particular the preservation of their copy number and position in the cell is critical in many eukaryotes. I propose to investigate, in an integrative and quantitative way, how centrioles are formed in the right numbers at the right time and place, and how they are maintained to ensure their function and inheritance. We first ask how centrioles guide their own assembly position and centriole copy number. Our recent work highlighted several properties of the system, including positive and negative feedbacks and spatial cues. We explore critical hypotheses through a combination of biochemistry, quantitative live cell microscopy and computational modelling. We then ask how the centrosome and the cell cycle are both coordinated. We recently identified the triggering event in centriole biogenesis and how its regulation is akin to cell cycle control of DNA replication and centromere assembly. We will explore new hypotheses to understand how assembly time is coupled to the cell cycle. Lastly, we ask how centriole maintenance is regulated. By studying centriole disappearance in the female germline we uncovered that centrioles need to be actively maintained by their surrounding matrix. We propose to investigate how that matrix provides stability to the centrioles, whether this is differently regulated in different cell types and the possible consequences of its misregulation for the organism (infertility and ciliopathy-like symptoms). We will take advantage of several experimental systems (in silico, ex-vivo, flies and human cells), tailoring the assay to the question and allowing for comparisons across experimental systems to provide a deeper understanding of the process and its regulation.
Summary
Centrioles assemble centrosomes and cilia/flagella, critical structures for cell division, polarity, motility and signalling, which are often deregulated in human disease. Centriole inheritance, in particular the preservation of their copy number and position in the cell is critical in many eukaryotes. I propose to investigate, in an integrative and quantitative way, how centrioles are formed in the right numbers at the right time and place, and how they are maintained to ensure their function and inheritance. We first ask how centrioles guide their own assembly position and centriole copy number. Our recent work highlighted several properties of the system, including positive and negative feedbacks and spatial cues. We explore critical hypotheses through a combination of biochemistry, quantitative live cell microscopy and computational modelling. We then ask how the centrosome and the cell cycle are both coordinated. We recently identified the triggering event in centriole biogenesis and how its regulation is akin to cell cycle control of DNA replication and centromere assembly. We will explore new hypotheses to understand how assembly time is coupled to the cell cycle. Lastly, we ask how centriole maintenance is regulated. By studying centriole disappearance in the female germline we uncovered that centrioles need to be actively maintained by their surrounding matrix. We propose to investigate how that matrix provides stability to the centrioles, whether this is differently regulated in different cell types and the possible consequences of its misregulation for the organism (infertility and ciliopathy-like symptoms). We will take advantage of several experimental systems (in silico, ex-vivo, flies and human cells), tailoring the assay to the question and allowing for comparisons across experimental systems to provide a deeper understanding of the process and its regulation.
Max ERC Funding
2 000 000 €
Duration
Start date: 2017-01-01, End date: 2021-12-31
Project acronym ChronosAntibiotics
Project Exploring the bacterial cell cycle to re-sensitize antibiotic-resistant bacteria
Researcher (PI) MARIANA LUISA TOMAS GOMES DE PINHO
Host Institution (HI) UNIVERSIDADE NOVA DE LISBOA
Call Details Consolidator Grant (CoG), LS6, ERC-2017-COG
Summary Over the next 35 years, antibiotic resistant bacteria are expected to kill more than 300 million people. The need to find alternative strategies for antimicrobial therapies remains a global challenge with several bottlenecks in the antibiotic discovery process. Using Staphylococcus aureus, the most common multidrug-resistant bacterium in the European Union and an excellent model organism for cell division in cocci, we propose:
(i) to find new pathways to re-sensitize resistant bacteria. Bacteria undergo major morphology changes during the cell cycle. We hypothesize that these changes generate windows of opportunity during which bacteria are more susceptible or more tolerant to the action of antibiotics. We will identify key regulators of the cell cycle in order to manipulate the duration of windows of opportunity for the action of existing antibiotics.
(ii) to develop new fluorescence-based reporters for whole-cell screenings of antimicrobial compounds with new modes of action, including compounds that arrest or delay the cell cycle; compounds that target non-essential pathways that are required for expression of resistance against existing antibiotics and therefore can be used as synergistic drugs for combination therapies; compounds that inhibit the production of virulence factors and compounds that revert persister states that are phenotypically resistant to antibiotics.
(iii) to unravel new modes of action of antibiotics by using the constructed reporter strains as powerful tools to learn how antibiotics act at the single cell level.
Over the past years, my group has become expert on the biology of S. aureus, has constructed powerful biological tools to study cell division and synthesis of the cell surface and has studied mechanisms of action of various antimicrobial compounds. We are therefore in a privileged position to quickly unravel the function of new players in the bacterial cell cycle and simultaneously contribute to accelerate antibiotic discovery.
Summary
Over the next 35 years, antibiotic resistant bacteria are expected to kill more than 300 million people. The need to find alternative strategies for antimicrobial therapies remains a global challenge with several bottlenecks in the antibiotic discovery process. Using Staphylococcus aureus, the most common multidrug-resistant bacterium in the European Union and an excellent model organism for cell division in cocci, we propose:
(i) to find new pathways to re-sensitize resistant bacteria. Bacteria undergo major morphology changes during the cell cycle. We hypothesize that these changes generate windows of opportunity during which bacteria are more susceptible or more tolerant to the action of antibiotics. We will identify key regulators of the cell cycle in order to manipulate the duration of windows of opportunity for the action of existing antibiotics.
(ii) to develop new fluorescence-based reporters for whole-cell screenings of antimicrobial compounds with new modes of action, including compounds that arrest or delay the cell cycle; compounds that target non-essential pathways that are required for expression of resistance against existing antibiotics and therefore can be used as synergistic drugs for combination therapies; compounds that inhibit the production of virulence factors and compounds that revert persister states that are phenotypically resistant to antibiotics.
(iii) to unravel new modes of action of antibiotics by using the constructed reporter strains as powerful tools to learn how antibiotics act at the single cell level.
Over the past years, my group has become expert on the biology of S. aureus, has constructed powerful biological tools to study cell division and synthesis of the cell surface and has studied mechanisms of action of various antimicrobial compounds. We are therefore in a privileged position to quickly unravel the function of new players in the bacterial cell cycle and simultaneously contribute to accelerate antibiotic discovery.
Max ERC Funding
2 533 500 €
Duration
Start date: 2018-03-01, End date: 2023-02-28
Project acronym CODECHECK
Project CRACKING THE CODE BEHIND MITOTIC FIDELITY: the roles of tubulin post-translational modifications and a chromosome separation checkpoint
Researcher (PI) Helder Jose Martins Maiato
Host Institution (HI) INSTITUTO DE BIOLOGIA MOLECULAR E CELULAR-IBMC
Call Details Consolidator Grant (CoG), LS3, ERC-2015-CoG
Summary During the human lifetime 10000 trillion cell divisions take place to ensure tissue homeostasis and several vital functions in the organism. Mitosis is the process that ensures that dividing cells preserve the chromosome number of their progenitors, while deviation from this, a condition known as aneuploidy, represents the most common feature in human cancers. Here we will test two original concepts with strong implications for chromosome segregation fidelity. The first concept is based on the “tubulin code” hypothesis, which predicts that molecular motors “read” tubulin post-translational modifications on spindle microtubules. Our proof-of-concept experiments demonstrate that tubulin detyrosination works as a navigation system that guides chromosomes towards the cell equator. Thus, in addition to regulating the motors required for chromosome motion, the cell might regulate the tracks in which they move on. We will combine proteomic, super-resolution and live-cell microscopy, with in vitro reconstitutions, to perform a comprehensive survey of the tubulin code and the respective implications for motors involved in chromosome motion, mitotic spindle assembly and correction of kinetochore-microtubule attachments. The second concept is centered on the recently uncovered chromosome separation checkpoint mediated by a midzone-associated Aurora B gradient, which delays nuclear envelope reformation in response to incompletely separated chromosomes. We aim to identify Aurora B targets involved in the spatiotemporal regulation of the anaphase-telophase transition. We will establish powerful live-cell microscopy assays and a novel mammalian model system to dissect how this checkpoint allows the detection and correction of lagging/long chromosomes and DNA bridges that would otherwise contribute to genomic instability. Overall, this work will establish a paradigm shift in our understanding of how spatial information is conveyed to faithfully segregate chromosomes during mitosis.
Summary
During the human lifetime 10000 trillion cell divisions take place to ensure tissue homeostasis and several vital functions in the organism. Mitosis is the process that ensures that dividing cells preserve the chromosome number of their progenitors, while deviation from this, a condition known as aneuploidy, represents the most common feature in human cancers. Here we will test two original concepts with strong implications for chromosome segregation fidelity. The first concept is based on the “tubulin code” hypothesis, which predicts that molecular motors “read” tubulin post-translational modifications on spindle microtubules. Our proof-of-concept experiments demonstrate that tubulin detyrosination works as a navigation system that guides chromosomes towards the cell equator. Thus, in addition to regulating the motors required for chromosome motion, the cell might regulate the tracks in which they move on. We will combine proteomic, super-resolution and live-cell microscopy, with in vitro reconstitutions, to perform a comprehensive survey of the tubulin code and the respective implications for motors involved in chromosome motion, mitotic spindle assembly and correction of kinetochore-microtubule attachments. The second concept is centered on the recently uncovered chromosome separation checkpoint mediated by a midzone-associated Aurora B gradient, which delays nuclear envelope reformation in response to incompletely separated chromosomes. We aim to identify Aurora B targets involved in the spatiotemporal regulation of the anaphase-telophase transition. We will establish powerful live-cell microscopy assays and a novel mammalian model system to dissect how this checkpoint allows the detection and correction of lagging/long chromosomes and DNA bridges that would otherwise contribute to genomic instability. Overall, this work will establish a paradigm shift in our understanding of how spatial information is conveyed to faithfully segregate chromosomes during mitosis.
Max ERC Funding
2 323 468 €
Duration
Start date: 2016-07-01, End date: 2021-06-30
Project acronym COGTOM
Project Cognitive tomography of mental representations
Researcher (PI) Máté Miklós LENGYEL
Host Institution (HI) KOZEP-EUROPAI EGYETEM
Call Details Consolidator Grant (CoG), SH4, ERC-2016-COG
Summary Internal models are fundamental to our understanding of how the mind constructs percepts, makes decisions, controls movements, and interacts with others. Yet, we lack principled quantitative methods to systematically estimate internal models from observable behaviour, and current approaches for discovering their mental representations remain heuristic and piecemeal. I propose to develop a set of novel 'doubly Bayesian' data analytical methods, using state-of-the-art Bayesian statistical and machine learning techniques to infer humans' internal models formalised as prior distributions in Bayesian models of cognition. This approach, cognitive tomography, takes a series of behavioural observations, each of which in itself may have very limited information content, and accumulates a detailed reconstruction of the internal model based on these observations. I also propose a set of stringent, quantifiable criteria which will be systematically applied at each step of the proposed work to rigorously assess the success of our approach. These methodological advances will allow us to track how the structured, task-general internal models that are so fundamental to humans' superior cognitive abilities, change over time as a result of decay, interference, and learning. We will apply cognitive tomography to a variety of experimental data sets, collected by our collaborators, in paradigms ranging from perceptual learning, through visual and motor structure learning, to social and concept learning. These analyses will allow us to conclusively and quantitatively test our central hypothesis that, rather than simply changing along a single 'memory strength' dimension, internal models typically change via complex and consistent patterns of transformations along multiple dimensions simultaneously. To facilitate the widespread use of our methods, we will release and support off-the-shelf usable implementations of our algorithms together with synthetic and real test data sets.
Summary
Internal models are fundamental to our understanding of how the mind constructs percepts, makes decisions, controls movements, and interacts with others. Yet, we lack principled quantitative methods to systematically estimate internal models from observable behaviour, and current approaches for discovering their mental representations remain heuristic and piecemeal. I propose to develop a set of novel 'doubly Bayesian' data analytical methods, using state-of-the-art Bayesian statistical and machine learning techniques to infer humans' internal models formalised as prior distributions in Bayesian models of cognition. This approach, cognitive tomography, takes a series of behavioural observations, each of which in itself may have very limited information content, and accumulates a detailed reconstruction of the internal model based on these observations. I also propose a set of stringent, quantifiable criteria which will be systematically applied at each step of the proposed work to rigorously assess the success of our approach. These methodological advances will allow us to track how the structured, task-general internal models that are so fundamental to humans' superior cognitive abilities, change over time as a result of decay, interference, and learning. We will apply cognitive tomography to a variety of experimental data sets, collected by our collaborators, in paradigms ranging from perceptual learning, through visual and motor structure learning, to social and concept learning. These analyses will allow us to conclusively and quantitatively test our central hypothesis that, rather than simply changing along a single 'memory strength' dimension, internal models typically change via complex and consistent patterns of transformations along multiple dimensions simultaneously. To facilitate the widespread use of our methods, we will release and support off-the-shelf usable implementations of our algorithms together with synthetic and real test data sets.
Max ERC Funding
1 179 462 €
Duration
Start date: 2017-05-01, End date: 2022-04-30
Project acronym COMPCON
Project Competition under (niche) construction
Researcher (PI) Sara NEWBERY RAPOSO DE MAGALHÃES
Host Institution (HI) FCIENCIAS.ID - ASSOCIACAO PARA A INVESTIGACAO E DESENVOLVIMENTO DE CIENCIAS
Call Details Consolidator Grant (CoG), LS8, ERC-2016-COG
Summary Interspecific competition is arguably the best interaction to address how individual trait variation and eco-evolutionary feedbacks shape species distributions and trait evolution, due to its indirect effects via the shared resource. However, a clear understanding of such feedbacks is only possible if each contributing factor can be manipulated independently. With COMPCON, we will address how individual variation, niche width, niche construction and the presence of competitors shape species distributions and trait evolution, using a system amenable to manipulation of all these variables. The system is composed of two spider mite species, Tetranychus urticae and T. ludeni, that up- and down-regulate plant defences (i.e., negative and positive niche construction, respectively). Tomato mutant plants with low defences will be used as an environment in which niche construction is not expressed. Furthermore, tomato plants will be grown under different cadmium concentrations, allowing quantitative variation of available niches. Using isogenic lines, we will measure individual variation in niche width, niche construction and competitive ability. Different combinations of lines will then be used to test key predictions of recent theory on how such variation affects coexistence with competitors. Subsequently, mite populations will evolve in environments with either one or more potential niches, in plants where niche construction is possible or not, and in presence or absence of competitors (coevolving or not). We will test how these selection pressures affect niche width, niche construction and competitive ability, as well as plant damage. Finally, we will re-derive isogenic lines from these treatments, to test how evolution under different scenarios affects individual variation in niche width.
COMPCON will shed new light on the role of competition in shaping eco-evolutionary communities, with bearings on disciplines ranging from macro-ecology to evolutionary genetics
Summary
Interspecific competition is arguably the best interaction to address how individual trait variation and eco-evolutionary feedbacks shape species distributions and trait evolution, due to its indirect effects via the shared resource. However, a clear understanding of such feedbacks is only possible if each contributing factor can be manipulated independently. With COMPCON, we will address how individual variation, niche width, niche construction and the presence of competitors shape species distributions and trait evolution, using a system amenable to manipulation of all these variables. The system is composed of two spider mite species, Tetranychus urticae and T. ludeni, that up- and down-regulate plant defences (i.e., negative and positive niche construction, respectively). Tomato mutant plants with low defences will be used as an environment in which niche construction is not expressed. Furthermore, tomato plants will be grown under different cadmium concentrations, allowing quantitative variation of available niches. Using isogenic lines, we will measure individual variation in niche width, niche construction and competitive ability. Different combinations of lines will then be used to test key predictions of recent theory on how such variation affects coexistence with competitors. Subsequently, mite populations will evolve in environments with either one or more potential niches, in plants where niche construction is possible or not, and in presence or absence of competitors (coevolving or not). We will test how these selection pressures affect niche width, niche construction and competitive ability, as well as plant damage. Finally, we will re-derive isogenic lines from these treatments, to test how evolution under different scenarios affects individual variation in niche width.
COMPCON will shed new light on the role of competition in shaping eco-evolutionary communities, with bearings on disciplines ranging from macro-ecology to evolutionary genetics
Max ERC Funding
1 999 275 €
Duration
Start date: 2017-05-01, End date: 2022-04-30
Project acronym DeCode
Project Dendrites and memory: role of dendritic spikes in information coding by hippocampal CA3 pyramidal neurons
Researcher (PI) Judit MAKARA
Host Institution (HI) INSTITUTE OF EXPERIMENTAL MEDICINE - HUNGARIAN ACADEMY OF SCIENCES
Call Details Consolidator Grant (CoG), LS5, ERC-2017-COG
Summary The hippocampus is essential for building episodic memories. Coding of locations, contexts or events in the hippocampus is based on the correlated activity of neuronal ensembles; however, the mechanisms promoting the recruitment of individual neurons into information-coding ensembles are poorly understood.
In particular, the recurrent synaptic network of pyramidal cells (PCs) in the hippocampal CA3 area, receiving external inputs from the entorhinal cortex and the dentate gyrus, is thought to be essential for associative memory. Current models of the associative functions of CA3 are mainly based on plasticity of these synaptic connections. Recent work by us and others however suggests that active, voltage-dependent properties of CA3PC dendrites may also promote ensemble functions. Dendritic voltage-dependent ion channels allow nonlinear amplification of spatiotemporally correlated synaptic inputs (such as those produced by ensemble activity) and can even generate local dendritic spikes, which may elicit specific action potential patterns and induce synaptic plasticity. Furthermore, dendritic processing may be modulated by activity-dependent regulation of dendritic ion channels. However, still little is known about the active properties of CA3PC dendrites and their functions during spatial coding or memory tasks.
The general aim of my research program is to understand the cellular mechanisms that underlie the formation of hippocampal memory-coding neuronal ensembles. Specifically, we will test the hypothesis that active input integration by dendrites of individual CA3PCs plays an important role in their recruitment into specific context-coding ensembles. By combining in vitro (patch-clamp electrophysiology and two-photon (2P) microscopy in slices) and in vivo (2P imaging and activity-dependent labelling in behaving rodents) approaches, we will provide an in-depth understanding of the dendritic components contributing to the generation of the CA3 ensemble code.
Summary
The hippocampus is essential for building episodic memories. Coding of locations, contexts or events in the hippocampus is based on the correlated activity of neuronal ensembles; however, the mechanisms promoting the recruitment of individual neurons into information-coding ensembles are poorly understood.
In particular, the recurrent synaptic network of pyramidal cells (PCs) in the hippocampal CA3 area, receiving external inputs from the entorhinal cortex and the dentate gyrus, is thought to be essential for associative memory. Current models of the associative functions of CA3 are mainly based on plasticity of these synaptic connections. Recent work by us and others however suggests that active, voltage-dependent properties of CA3PC dendrites may also promote ensemble functions. Dendritic voltage-dependent ion channels allow nonlinear amplification of spatiotemporally correlated synaptic inputs (such as those produced by ensemble activity) and can even generate local dendritic spikes, which may elicit specific action potential patterns and induce synaptic plasticity. Furthermore, dendritic processing may be modulated by activity-dependent regulation of dendritic ion channels. However, still little is known about the active properties of CA3PC dendrites and their functions during spatial coding or memory tasks.
The general aim of my research program is to understand the cellular mechanisms that underlie the formation of hippocampal memory-coding neuronal ensembles. Specifically, we will test the hypothesis that active input integration by dendrites of individual CA3PCs plays an important role in their recruitment into specific context-coding ensembles. By combining in vitro (patch-clamp electrophysiology and two-photon (2P) microscopy in slices) and in vivo (2P imaging and activity-dependent labelling in behaving rodents) approaches, we will provide an in-depth understanding of the dendritic components contributing to the generation of the CA3 ensemble code.
Max ERC Funding
1 990 314 €
Duration
Start date: 2018-06-01, End date: 2023-05-31
Project acronym DevoTed_miR
Project MicroRNA determinants of the balance between effector and regulatory T cells in vivo
Researcher (PI) Bruno Miguel De Carvalho e Silva Santos
Host Institution (HI) INSTITUTO DE MEDICINA MOLECULAR JOAO LOBO ANTUNES
Call Details Consolidator Grant (CoG), LS6, ERC-2014-CoG
Summary T lymphocytes display potent pro- or anti-inflammatory properties, which typically associate with distinct effector (Teff) versus regulatory (Treg) cell subsets. Based on published and our preliminary data showing a major impact of microRNAs on T cell differentiation and (auto)immune pathology, my proposal aims to dissect the miRNA networks that control the balance between Teff and Treg subsets in vivo, in various experimental models of infection and autoimmunity.
We will focus on three critical mediators of T cell functions: interferon-gamma (IFN-g) and interleukin-17A (IL-17), highly pro-inflammatory Teff cytokines; and Foxp3, the transcription factor that confers Treg suppressive properties. To track the activity of these key genes, we will generate a new Ifng/ Il17/ Foxp3 triple reporter mouse, from which we will isolate Teff and Treg subsets to determine their genome-wide miRNA profiles and specific signatures in vivo. We will investigate both natural (thymic-derived and present in naïve mice) and induced (in the periphery upon challenge) Teff and Treg subsets, as they make distinct contributions to the immune response. We will identify miRNAs selectively expressed in Teff (Ifng+ or Il17+) versus Treg (Foxp3+) subsets of various lineages (CD4+, CD8+, gamma-delta or NKT) in each in vivo model; assess whether they are induced during thymic development or upon peripheral activation; and determine the robustness of subset-specific miRNA profiles across various in vivo challenges.
We will then use loss- and gain-of-function strategies to define the individual miRNAs that impact Teff or Treg differentiation and disease pathogenesis; dissect the external cues and intracellular mechanisms that regulate miRNA expression; and identify the mRNA networks controlled by key miRNAs in Teff and Treg differentiation. I expect this project to provide major conceptual and experimental advances towards manipulating miRNAs either to boost immunity or to treat autoimmunity.
Summary
T lymphocytes display potent pro- or anti-inflammatory properties, which typically associate with distinct effector (Teff) versus regulatory (Treg) cell subsets. Based on published and our preliminary data showing a major impact of microRNAs on T cell differentiation and (auto)immune pathology, my proposal aims to dissect the miRNA networks that control the balance between Teff and Treg subsets in vivo, in various experimental models of infection and autoimmunity.
We will focus on three critical mediators of T cell functions: interferon-gamma (IFN-g) and interleukin-17A (IL-17), highly pro-inflammatory Teff cytokines; and Foxp3, the transcription factor that confers Treg suppressive properties. To track the activity of these key genes, we will generate a new Ifng/ Il17/ Foxp3 triple reporter mouse, from which we will isolate Teff and Treg subsets to determine their genome-wide miRNA profiles and specific signatures in vivo. We will investigate both natural (thymic-derived and present in naïve mice) and induced (in the periphery upon challenge) Teff and Treg subsets, as they make distinct contributions to the immune response. We will identify miRNAs selectively expressed in Teff (Ifng+ or Il17+) versus Treg (Foxp3+) subsets of various lineages (CD4+, CD8+, gamma-delta or NKT) in each in vivo model; assess whether they are induced during thymic development or upon peripheral activation; and determine the robustness of subset-specific miRNA profiles across various in vivo challenges.
We will then use loss- and gain-of-function strategies to define the individual miRNAs that impact Teff or Treg differentiation and disease pathogenesis; dissect the external cues and intracellular mechanisms that regulate miRNA expression; and identify the mRNA networks controlled by key miRNAs in Teff and Treg differentiation. I expect this project to provide major conceptual and experimental advances towards manipulating miRNAs either to boost immunity or to treat autoimmunity.
Max ERC Funding
2 000 000 €
Duration
Start date: 2015-07-01, End date: 2020-06-30
Project acronym DYCOCIRC
Project Basal ganglia circuit mechanisms underlying dynamic cognitive behavior
Researcher (PI) Joseph PATON
Host Institution (HI) FUNDACAO D. ANNA SOMMER CHAMPALIMAUD E DR. CARLOS MONTEZ CHAMPALIMAUD
Call Details Consolidator Grant (CoG), LS5, ERC-2017-COG
Summary You’re faced with a difficult choice. What do you do? Most people will, either explicitly or implicitly, weigh the possible consequences their decision. This involves an internal journey through possible events. Its these kinds of dynamic processes and their mapping onto behavior that characterize higher brain function. And yet, their very internal nature is both what makes them of critical interest and so difficult to study. Here, we propose to study a simple, well-controlled decision-making behavior wherein mice have to generate a dynamic, internal representation of elapsed time in order to make choices that result in reward. We focus on frontal cortico-basal ganglia circuits and their dopaminergic inputs that together are broadly implicated in cognition and involved in the production of this particular behavior. We have demonstrated previously that striatal population dynamics and dopamine neuron activity both correlate with and exert control over animals’ judgments. Having identified key signals at multiple stages of the BG circuit related to this decision in rats and mice, my laboratory is now uniquely poised to dissect the circuit mechanisms by which such signals are generated and transformed into actions. Specifically, we will 1) Measure activity of specific cell types at multiple stages of the BG as mice judge duration. 2) Image and manipulate the activity of DA neurons while recording from neural populations in the BG to determine the relationship between neuromodulatory input, neural dynamics, and behavior. 3) Relate the activity of cortico-striatal inputs to striatal responses during behavior to understand the computational and circuit bases of striatal activity. These experiments promise to unlock deep mysteries regarding how animals free themselves from the immediacy of the current moment, learning, planning, and choosing their path toward a safer, more fruitful, and satisfying existence.
Summary
You’re faced with a difficult choice. What do you do? Most people will, either explicitly or implicitly, weigh the possible consequences their decision. This involves an internal journey through possible events. Its these kinds of dynamic processes and their mapping onto behavior that characterize higher brain function. And yet, their very internal nature is both what makes them of critical interest and so difficult to study. Here, we propose to study a simple, well-controlled decision-making behavior wherein mice have to generate a dynamic, internal representation of elapsed time in order to make choices that result in reward. We focus on frontal cortico-basal ganglia circuits and their dopaminergic inputs that together are broadly implicated in cognition and involved in the production of this particular behavior. We have demonstrated previously that striatal population dynamics and dopamine neuron activity both correlate with and exert control over animals’ judgments. Having identified key signals at multiple stages of the BG circuit related to this decision in rats and mice, my laboratory is now uniquely poised to dissect the circuit mechanisms by which such signals are generated and transformed into actions. Specifically, we will 1) Measure activity of specific cell types at multiple stages of the BG as mice judge duration. 2) Image and manipulate the activity of DA neurons while recording from neural populations in the BG to determine the relationship between neuromodulatory input, neural dynamics, and behavior. 3) Relate the activity of cortico-striatal inputs to striatal responses during behavior to understand the computational and circuit bases of striatal activity. These experiments promise to unlock deep mysteries regarding how animals free themselves from the immediacy of the current moment, learning, planning, and choosing their path toward a safer, more fruitful, and satisfying existence.
Max ERC Funding
2 000 000 €
Duration
Start date: 2018-04-01, End date: 2023-03-31
