Project acronym ANXIETY MECHANISMS
Project Neurocognitive mechanisms of human anxiety: identifying and
targeting disrupted function
Researcher (PI) Sonia Jane Bishop
Host Institution (HI) THE CHANCELLOR, MASTERS AND SCHOLARS OF THE UNIVERSITY OF OXFORD
Call Details Starting Grant (StG), LS5, ERC-2010-StG_20091118
Summary Within a 12 month period, 20% of adults will meet criteria for one or more clinical anxiety disorders (ADs). These disorders are hugely disruptive, placing an emotional burden on individuals and their families. While both cognitive behavioural therapy and pharmacological treatment are widely viewed as effective strategies for managing ADs, systematic review of the literature reveals that only 30–45% of patients demonstrate a marked response to treatment (anxiety levels being reduced into the nonaffected range). In addition, a significant proportion of initial responders relapse after treatment is discontinued. There is hence a real and marked need to improve upon current approaches to AD treatment.
One possible avenue for improving response rates is through optimizing initial treatment selection. Specifically, it is possible that certain individuals might respond better to cognitive interventions while others might respond better to pharmacological treatment. Recently it has been suggested that there may be two or more distinct biological pathways disrupted in anxiety. If this is the case, then specification of these pathways may be an important step in predicting which individuals are likely to respond to which treatment. Few studies have focused upon this issue and, in particular, upon identifying neural markers that might predict response to cognitive (as opposed to pharmacological) intervention. The proposed research aims to address this. Specifically, it tests the hypothesis that there are at least two mechanisms disrupted in ADs, one entailing amygdala hyper-responsivity to cues that signal threat, the other impoverished recruitment of frontal regions that support cognitive and emotional regulation.
Two series of functional magnetic resonance imaging experiments will be conducted. These will investigate differences in amygdala and frontal function during (a) attentional processing and (b) fear conditioning. Initial clinical experiments will investigate whether Generalised Anxiety Disorder and Specific Phobia involve differing degrees of disruption to frontal versus amygdala function during these tasks. This work will feed into training studies, the goal being to characterize AD patient subgroups that benefit from cognitive training.
Summary
Within a 12 month period, 20% of adults will meet criteria for one or more clinical anxiety disorders (ADs). These disorders are hugely disruptive, placing an emotional burden on individuals and their families. While both cognitive behavioural therapy and pharmacological treatment are widely viewed as effective strategies for managing ADs, systematic review of the literature reveals that only 30–45% of patients demonstrate a marked response to treatment (anxiety levels being reduced into the nonaffected range). In addition, a significant proportion of initial responders relapse after treatment is discontinued. There is hence a real and marked need to improve upon current approaches to AD treatment.
One possible avenue for improving response rates is through optimizing initial treatment selection. Specifically, it is possible that certain individuals might respond better to cognitive interventions while others might respond better to pharmacological treatment. Recently it has been suggested that there may be two or more distinct biological pathways disrupted in anxiety. If this is the case, then specification of these pathways may be an important step in predicting which individuals are likely to respond to which treatment. Few studies have focused upon this issue and, in particular, upon identifying neural markers that might predict response to cognitive (as opposed to pharmacological) intervention. The proposed research aims to address this. Specifically, it tests the hypothesis that there are at least two mechanisms disrupted in ADs, one entailing amygdala hyper-responsivity to cues that signal threat, the other impoverished recruitment of frontal regions that support cognitive and emotional regulation.
Two series of functional magnetic resonance imaging experiments will be conducted. These will investigate differences in amygdala and frontal function during (a) attentional processing and (b) fear conditioning. Initial clinical experiments will investigate whether Generalised Anxiety Disorder and Specific Phobia involve differing degrees of disruption to frontal versus amygdala function during these tasks. This work will feed into training studies, the goal being to characterize AD patient subgroups that benefit from cognitive training.
Max ERC Funding
1 708 407 €
Duration
Start date: 2011-04-01, End date: 2016-08-31
Project acronym ARTTOUCH
Project Generating artificial touch: from the contribution of single tactile afferents to the encoding of complex percepts, and their implications for clinical innovation
Researcher (PI) Rochelle ACKERLEY
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Call Details Consolidator Grant (CoG), LS5, ERC-2017-COG
Summary Somatosensation encompass a wide range of processes, from feeling touch to temperature, as well as experiencing pleasure and pain. When afferent inputs are degraded or removed, such as in neuropathies or amputation, exploring the world becomes extremely difficult. Chronic pain is a major health issue that greatly diminishes quality of life and is one of the most disabling and costly conditions in Europe. The loss of a body part is common due to accidents, tumours, or peripheral diseases, and it has instantaneous effects on somatosensory functioning. Treating such disorders entails detailed knowledge about how somatosensory signals are encoded. Understanding these processes will enable the restoration of healthy function, such as providing real-time, naturalistic feedback in prostheses. To date, no prosthesis currently provides long-term sensory feedback, yet accomplishing this will lead to great quality of life improvements. The present proposal aims to uncover how basic tactile processes are encoded and represented centrally, as well as how more complex somatosensation is generated (e.g. wetness, pleasantness). Novel investigations will be conducted in humans to probe these mechanisms, including peripheral in vivo recording (microneurography) and neural stimulation, combined with advanced brain imaging and behavioural experiments. Preliminary work has shown the feasibility of the approach, where it is possible to visualise the activation of single mechanoreceptive afferents in the human brain. The multi-disciplinary approach unites detailed, high-resolution, functional investigations with actual sensations generated. The results will elucidate how basic and complex somatosensory processes are encoded, providing insights into the recovery of such signals. The knowledge gained aims to provide pain-free, efficient diagnostic capabilities for detecting and quantifying a range of somatosensory disorders, as well as identifying new potential therapeutic targets.
Summary
Somatosensation encompass a wide range of processes, from feeling touch to temperature, as well as experiencing pleasure and pain. When afferent inputs are degraded or removed, such as in neuropathies or amputation, exploring the world becomes extremely difficult. Chronic pain is a major health issue that greatly diminishes quality of life and is one of the most disabling and costly conditions in Europe. The loss of a body part is common due to accidents, tumours, or peripheral diseases, and it has instantaneous effects on somatosensory functioning. Treating such disorders entails detailed knowledge about how somatosensory signals are encoded. Understanding these processes will enable the restoration of healthy function, such as providing real-time, naturalistic feedback in prostheses. To date, no prosthesis currently provides long-term sensory feedback, yet accomplishing this will lead to great quality of life improvements. The present proposal aims to uncover how basic tactile processes are encoded and represented centrally, as well as how more complex somatosensation is generated (e.g. wetness, pleasantness). Novel investigations will be conducted in humans to probe these mechanisms, including peripheral in vivo recording (microneurography) and neural stimulation, combined with advanced brain imaging and behavioural experiments. Preliminary work has shown the feasibility of the approach, where it is possible to visualise the activation of single mechanoreceptive afferents in the human brain. The multi-disciplinary approach unites detailed, high-resolution, functional investigations with actual sensations generated. The results will elucidate how basic and complex somatosensory processes are encoded, providing insights into the recovery of such signals. The knowledge gained aims to provide pain-free, efficient diagnostic capabilities for detecting and quantifying a range of somatosensory disorders, as well as identifying new potential therapeutic targets.
Max ERC Funding
1 223 639 €
Duration
Start date: 2019-01-01, End date: 2023-12-31
Project acronym AstroFunc
Project Molecular Studies of Astrocyte Function in Health and Disease
Researcher (PI) Matthew Guy Holt
Host Institution (HI) VIB VZW
Call Details Starting Grant (StG), LS5, ERC-2011-StG_20101109
Summary Brain consists of two basic cell types – neurons and glia. However, the study of glia in brain function has traditionally been neglected in favor of their more “illustrious” counter-parts – neurons that are classed as the computational units of the brain. Glia have usually been classed as “brain glue” - a supportive matrix on which neurons grow and function. However, recent evidence suggests that glia are more than passive “glue” and actually modulate neuronal function. This has lead to the proposal of a “tripartite synapse”, which recognizes pre- and postsynaptic neuronal elements and glia as a unit.
However, what is still lacking is rudimentary information on how these cells actually function in situ. Here we propose taking a “bottom-up” approach, by identifying the molecules (and interactions) that control glial function in situ. This is complicated by the fact that glia show profound changes when placed into culture. To circumvent this, we will use recently developed cell sorting techniques, to rapidly isolate genetically marked glial cells from brain – which can then be analyzed using advanced biochemical and physiological techniques. The long-term aim is to identify proteins that can be “tagged” using transgenic technologies to allow protein function to be studied in real-time in vivo, using sophisticated imaging techniques. Given the number of proteins that may be identified we envisage developing new methods of generating transgenic animals that provide an attractive alternative to current “state-of-the art” technology.
The importance of studying glial function is given by the fact that every major brain pathology shows reactive gliosis. In the time it takes to read this abstract, 5 people in the EU will have suffered a stroke – not to mention those who suffer other forms of neurotrauma. Thus, understanding glial function is not only critical to understanding normal brain function, but also for relieving the burden of severe neurological injury and disease
Summary
Brain consists of two basic cell types – neurons and glia. However, the study of glia in brain function has traditionally been neglected in favor of their more “illustrious” counter-parts – neurons that are classed as the computational units of the brain. Glia have usually been classed as “brain glue” - a supportive matrix on which neurons grow and function. However, recent evidence suggests that glia are more than passive “glue” and actually modulate neuronal function. This has lead to the proposal of a “tripartite synapse”, which recognizes pre- and postsynaptic neuronal elements and glia as a unit.
However, what is still lacking is rudimentary information on how these cells actually function in situ. Here we propose taking a “bottom-up” approach, by identifying the molecules (and interactions) that control glial function in situ. This is complicated by the fact that glia show profound changes when placed into culture. To circumvent this, we will use recently developed cell sorting techniques, to rapidly isolate genetically marked glial cells from brain – which can then be analyzed using advanced biochemical and physiological techniques. The long-term aim is to identify proteins that can be “tagged” using transgenic technologies to allow protein function to be studied in real-time in vivo, using sophisticated imaging techniques. Given the number of proteins that may be identified we envisage developing new methods of generating transgenic animals that provide an attractive alternative to current “state-of-the art” technology.
The importance of studying glial function is given by the fact that every major brain pathology shows reactive gliosis. In the time it takes to read this abstract, 5 people in the EU will have suffered a stroke – not to mention those who suffer other forms of neurotrauma. Thus, understanding glial function is not only critical to understanding normal brain function, but also for relieving the burden of severe neurological injury and disease
Max ERC Funding
1 490 168 €
Duration
Start date: 2012-01-01, End date: 2016-12-31
Project acronym astromnesis
Project The language of astrocytes: multilevel analysis to understand astrocyte communication and its role in memory-related brain operations and in cognitive behavior
Researcher (PI) Andrea Volterra
Host Institution (HI) UNIVERSITE DE LAUSANNE
Call Details Advanced Grant (AdG), LS5, ERC-2013-ADG
Summary In the 90s, two landmark observations brought to a paradigm shift about the role of astrocytes in brain function: 1) astrocytes respond to signals coming from other cells with transient Ca2+ elevations; 2) Ca2+ transients in astrocytes trigger release of neuroactive and vasoactive agents. Since then, many modulatory astrocytic actions and mechanisms were described, forming a complex - partly contradictory - picture, in which the exact roles and modes of astrocyte action remain ill defined. Our project wants to bring light into the “language of astrocytes”, i.e. into how they communicate with neurons and, ultimately, address their role in brain computations and cognitive behavior. To this end we will perform 4 complementary levels of analysis using highly innovative methodologies in order to obtain unprecedented results. We will study: 1) the subcellular organization of astrocytes underlying local microdomain communications by use of correlative light-electron microscopy; 2) the way individual astrocytes integrate inputs and control synaptic ensembles using 3D two-photon imaging, genetically-encoded Ca2+ indicators, optogenetics and electrophysiology; 3) the contribution of astrocyte ensembles to behavior-relevant circuit operations using miniaturized microscopes capturing neuronal/astrocytic population dynamics in freely-moving mice during memory tests; 4) the contribution of astrocytic signalling mechanisms to cognitive behavior using a set of new mouse lines with conditional, astrocyte-specific genetic modification of signalling pathways. We expect that this combination of groundbreaking ideas, innovative technologies and multilevel analysis makes our project highly attractive to the neuroscience community at large, bridging aspects of molecular, cellular, systems and behavioral neuroscience, with the goal of leading from a provocative hypothesis to the conclusive demonstration of whether and how “the language of astrocytes” participates in memory and cognition.
Summary
In the 90s, two landmark observations brought to a paradigm shift about the role of astrocytes in brain function: 1) astrocytes respond to signals coming from other cells with transient Ca2+ elevations; 2) Ca2+ transients in astrocytes trigger release of neuroactive and vasoactive agents. Since then, many modulatory astrocytic actions and mechanisms were described, forming a complex - partly contradictory - picture, in which the exact roles and modes of astrocyte action remain ill defined. Our project wants to bring light into the “language of astrocytes”, i.e. into how they communicate with neurons and, ultimately, address their role in brain computations and cognitive behavior. To this end we will perform 4 complementary levels of analysis using highly innovative methodologies in order to obtain unprecedented results. We will study: 1) the subcellular organization of astrocytes underlying local microdomain communications by use of correlative light-electron microscopy; 2) the way individual astrocytes integrate inputs and control synaptic ensembles using 3D two-photon imaging, genetically-encoded Ca2+ indicators, optogenetics and electrophysiology; 3) the contribution of astrocyte ensembles to behavior-relevant circuit operations using miniaturized microscopes capturing neuronal/astrocytic population dynamics in freely-moving mice during memory tests; 4) the contribution of astrocytic signalling mechanisms to cognitive behavior using a set of new mouse lines with conditional, astrocyte-specific genetic modification of signalling pathways. We expect that this combination of groundbreaking ideas, innovative technologies and multilevel analysis makes our project highly attractive to the neuroscience community at large, bridging aspects of molecular, cellular, systems and behavioral neuroscience, with the goal of leading from a provocative hypothesis to the conclusive demonstration of whether and how “the language of astrocytes” participates in memory and cognition.
Max ERC Funding
2 513 896 €
Duration
Start date: 2014-02-01, End date: 2019-01-31
Project acronym AstroNeuroCrosstalk
Project Astrocyte-Neuronal Crosstalk in Obesity and Diabetes
Researcher (PI) Cristina GARCÍA CÁCERES
Host Institution (HI) HELMHOLTZ ZENTRUM MUENCHEN DEUTSCHES FORSCHUNGSZENTRUM FUER GESUNDHEIT UND UMWELT GMBH
Call Details Starting Grant (StG), LS5, ERC-2017-STG
Summary Despite considerable efforts aimed at prevention and treatment, the prevalence of obesity and type 2 diabetes has increased at an alarming rate worldwide over recent decades. Given the urgent need to develop safe and efficient anti-obesity drugs, the scientific community has to intensify efforts to better understand the mechanisms involved in the pathogenesis of obesity. Based on human genome-wide association studies and targeted mouse mutagenesis models, it has recently emerged that the brain controls most aspects of systemic metabolism and that obesity may be a brain disease. I have recently shown that like neurons, astrocytes also respond to circulating nutrients, and they cooperate with neurons to efficiently regulate energy metabolism. So far, the study of brain circuits controlling energy balance has focused on neurons, ignoring the presence and role of astrocytes. Importantly, our studies were the first to describe that exposure to a high-fat, highsugar (HFHS) diet triggers hypothalamic astrogliosis prior to significant body weight gain, indicating a potentially important role in promoting obesity. Overall, my recent findings suggest a novel model in which astrocytes are actively involved in the central nervous system (CNS) control of metabolism, likely including active crosstalk between astrocytes and neurons. To test this hypothetical model, I propose to develop a functional understanding of astroglia-neuronal communication in the CNS control of metabolism focusing on: 1) dissecting the ability of astrocytes to release gliotransmitters to neurons, 2) assessing how astrocytes respond to neuronal activity, and 3) determining if HFHS-induced astrogliosis interrupts this crosstalk and contributes to the development of obesity and type 2 diabetes. These studies aim to uncover the molecular underpinnings of astrocyte-neuron inputs regulating metabolism in health and disease so as to
inspire and enable novel therapeutic strategies to fight diabetes and obesity.
Summary
Despite considerable efforts aimed at prevention and treatment, the prevalence of obesity and type 2 diabetes has increased at an alarming rate worldwide over recent decades. Given the urgent need to develop safe and efficient anti-obesity drugs, the scientific community has to intensify efforts to better understand the mechanisms involved in the pathogenesis of obesity. Based on human genome-wide association studies and targeted mouse mutagenesis models, it has recently emerged that the brain controls most aspects of systemic metabolism and that obesity may be a brain disease. I have recently shown that like neurons, astrocytes also respond to circulating nutrients, and they cooperate with neurons to efficiently regulate energy metabolism. So far, the study of brain circuits controlling energy balance has focused on neurons, ignoring the presence and role of astrocytes. Importantly, our studies were the first to describe that exposure to a high-fat, highsugar (HFHS) diet triggers hypothalamic astrogliosis prior to significant body weight gain, indicating a potentially important role in promoting obesity. Overall, my recent findings suggest a novel model in which astrocytes are actively involved in the central nervous system (CNS) control of metabolism, likely including active crosstalk between astrocytes and neurons. To test this hypothetical model, I propose to develop a functional understanding of astroglia-neuronal communication in the CNS control of metabolism focusing on: 1) dissecting the ability of astrocytes to release gliotransmitters to neurons, 2) assessing how astrocytes respond to neuronal activity, and 3) determining if HFHS-induced astrogliosis interrupts this crosstalk and contributes to the development of obesity and type 2 diabetes. These studies aim to uncover the molecular underpinnings of astrocyte-neuron inputs regulating metabolism in health and disease so as to
inspire and enable novel therapeutic strategies to fight diabetes and obesity.
Max ERC Funding
1 499 938 €
Duration
Start date: 2018-01-01, End date: 2022-12-31
Project acronym AstroWireSyn
Project Wiring synaptic circuits with astroglial connexins: mechanisms, dynamics and impact for critical period plasticity
Researcher (PI) Nathalie Rouach
Host Institution (HI) COLLEGE DE FRANCE
Call Details Consolidator Grant (CoG), LS5, ERC-2015-CoG
Summary Brain information processing is commonly thought to be a neuronal performance. However recent data point to a key role of astrocytes in brain development, activity and pathology. Indeed astrocytes are now viewed as crucial elements of the brain circuitry that control synapse formation, maturation, activity and elimination. How do astrocytes exert such control is matter of intense research, as they are now known to participate in critical developmental periods as well as in psychiatric disorders involving synapse alterations. Thus unraveling how astrocytes control synaptic circuit formation and maturation is crucial, not only for our understanding of brain development, but also for identifying novel therapeutic targets.
We recently found that connexin 30 (Cx30), an astroglial gap junction subunit expressed postnatally, tunes synaptic activity via an unprecedented non-channel function setting the proximity of glial processes to synaptic clefts, essential for synaptic glutamate clearance efficacy. Our work not only reveals Cx30 as a key determinant of glial synapse coverage, but also extends the classical model of neuroglial interactions in which astrocytes are generally considered as extrasynaptic elements indirectly regulating neurotransmission. Yet the molecular mechanisms involved in such control, its dynamic regulation by activity and impact in a native developmental context are unknown. We will now address these important questions, focusing on the involvement of this novel astroglial function in wiring developing synaptic circuits.
Thus using a multidisciplinary approach we will investigate:
1) the molecular and cellular mechanisms underlying Cx30 regulation of synaptic function
2) the activity-dependent dynamics of Cx30 function at synapses
3) a role for Cx30 in wiring synaptic circuits during critical developmental periods
This ambitious project will provide essential knowledge on the molecular mechanisms underlying astroglial control of synaptic circuits.
Summary
Brain information processing is commonly thought to be a neuronal performance. However recent data point to a key role of astrocytes in brain development, activity and pathology. Indeed astrocytes are now viewed as crucial elements of the brain circuitry that control synapse formation, maturation, activity and elimination. How do astrocytes exert such control is matter of intense research, as they are now known to participate in critical developmental periods as well as in psychiatric disorders involving synapse alterations. Thus unraveling how astrocytes control synaptic circuit formation and maturation is crucial, not only for our understanding of brain development, but also for identifying novel therapeutic targets.
We recently found that connexin 30 (Cx30), an astroglial gap junction subunit expressed postnatally, tunes synaptic activity via an unprecedented non-channel function setting the proximity of glial processes to synaptic clefts, essential for synaptic glutamate clearance efficacy. Our work not only reveals Cx30 as a key determinant of glial synapse coverage, but also extends the classical model of neuroglial interactions in which astrocytes are generally considered as extrasynaptic elements indirectly regulating neurotransmission. Yet the molecular mechanisms involved in such control, its dynamic regulation by activity and impact in a native developmental context are unknown. We will now address these important questions, focusing on the involvement of this novel astroglial function in wiring developing synaptic circuits.
Thus using a multidisciplinary approach we will investigate:
1) the molecular and cellular mechanisms underlying Cx30 regulation of synaptic function
2) the activity-dependent dynamics of Cx30 function at synapses
3) a role for Cx30 in wiring synaptic circuits during critical developmental periods
This ambitious project will provide essential knowledge on the molecular mechanisms underlying astroglial control of synaptic circuits.
Max ERC Funding
2 000 000 €
Duration
Start date: 2016-10-01, End date: 2021-09-30
Project acronym AttentionCircuits
Project Modulation of neocortical microcircuits for attention
Researcher (PI) Johannes Jakob Letzkus
Host Institution (HI) MAX-PLANCK-GESELLSCHAFT ZUR FORDERUNG DER WISSENSCHAFTEN EV
Call Details Starting Grant (StG), LS5, ERC-2013-StG
Summary At every moment in time, the brain receives a vast amount of sensory information about the environment. This makes attention, the process by which we select currently relevant stimuli for processing and ignore irrelevant input, a fundamentally important brain function. Studies in primates have yielded a detailed description of how attention to a stimulus modifies the responses of neuronal ensembles in visual cortex, but how this modulation is produced mechanistically in the circuit is not well understood. Neuronal circuits comprise a large variety of neuron types, and to gain mechanistic insights, and to treat specific diseases of the nervous system, it is crucial to characterize the contribution of different identified cell types to information processing. Inhibition supplied by a small yet highly diverse set of interneurons controls all aspects of cortical function, and the central hypothesis of this proposal is that differential modulation of genetically-defined interneuron types is a key mechanism of attention in visual cortex. To identify the interneuron types underlying attentional modulation and to investigate how this, in turn, affects computations in the circuit we will use an innovative multidisciplinary approach combining genetic targeting in mice with cutting-edge in vivo 2-photon microscopy-based recordings and selective optogenetic manipulation of activity. Importantly, a key set of experiments will test whether the observed neuronal mechanisms are causally involved in attention at the level of behavior, the ultimate readout of the computations we are interested in. The expected results will provide a detailed, mechanistic dissection of the neuronal basis of attention. Beyond attention, selection of different functional states of the same hard-wired circuit by modulatory input is a fundamental, but poorly understood, phenomenon in the brain, and we predict that our insights will elucidate similar mechanisms in other brain areas and functional contexts.
Summary
At every moment in time, the brain receives a vast amount of sensory information about the environment. This makes attention, the process by which we select currently relevant stimuli for processing and ignore irrelevant input, a fundamentally important brain function. Studies in primates have yielded a detailed description of how attention to a stimulus modifies the responses of neuronal ensembles in visual cortex, but how this modulation is produced mechanistically in the circuit is not well understood. Neuronal circuits comprise a large variety of neuron types, and to gain mechanistic insights, and to treat specific diseases of the nervous system, it is crucial to characterize the contribution of different identified cell types to information processing. Inhibition supplied by a small yet highly diverse set of interneurons controls all aspects of cortical function, and the central hypothesis of this proposal is that differential modulation of genetically-defined interneuron types is a key mechanism of attention in visual cortex. To identify the interneuron types underlying attentional modulation and to investigate how this, in turn, affects computations in the circuit we will use an innovative multidisciplinary approach combining genetic targeting in mice with cutting-edge in vivo 2-photon microscopy-based recordings and selective optogenetic manipulation of activity. Importantly, a key set of experiments will test whether the observed neuronal mechanisms are causally involved in attention at the level of behavior, the ultimate readout of the computations we are interested in. The expected results will provide a detailed, mechanistic dissection of the neuronal basis of attention. Beyond attention, selection of different functional states of the same hard-wired circuit by modulatory input is a fundamental, but poorly understood, phenomenon in the brain, and we predict that our insights will elucidate similar mechanisms in other brain areas and functional contexts.
Max ERC Funding
1 466 505 €
Duration
Start date: 2014-02-01, End date: 2019-01-31
Project acronym AVIANEGG
Project Evolutionary genetics in a ‘classical’ avian study system by high throughput transcriptome sequencing and SNP genotyping
Researcher (PI) Jon Slate
Host Institution (HI) THE UNIVERSITY OF SHEFFIELD
Call Details Starting Grant (StG), LS5, ERC-2007-StG
Summary Long-term studies of free-living vertebrate populations have proved a rich resource for understanding evolutionary and ecological processes, because individuals’ life histories can be measured by tracking them from birth/hatching through to death. In recent years the ‘animal model’ has been applied to pedigreed long-term study populations with great success, dramatically advancing our understanding of quantitative genetic parameters such as heritabilities, genetic correlations and plasticities of traits that are relevant to microevolutionary responses to environmental change. Unfortunately, quantitative genetic approaches have one major drawback – they cannot identify the actual genes responsible for genetic variation. Therefore, it is impossible to link evolutionary responses to a changing environment to molecular genetic variation, making our picture of the process incomplete. Many of the best long-term studies have been conducted in passerine birds. Unfortunately genomics resources are only available for two model avian species, and are absent for bird species that are studied in the wild. I will fill this gap by exploiting recent advances in genomics technology to sequence the entire transcriptome of the longest running study of wild birds – the great tit population in Wytham Woods, Oxford. Having identified most of the sequence variation in the great tit transcriptome, I will then genotype all birds for whom phenotype records and blood samples are available This will be, by far, the largest phenotype-genotype dataset of any free-living vertebrate population. I will then use gene mapping techniques to identify genes and genomic regions responsible for variation in a number of key traits such as lifetime recruitment, clutch size and breeding/laying date. This will result in a greater understanding, at the molecular level, how microevolutionary change can arise (or be constrained).
Summary
Long-term studies of free-living vertebrate populations have proved a rich resource for understanding evolutionary and ecological processes, because individuals’ life histories can be measured by tracking them from birth/hatching through to death. In recent years the ‘animal model’ has been applied to pedigreed long-term study populations with great success, dramatically advancing our understanding of quantitative genetic parameters such as heritabilities, genetic correlations and plasticities of traits that are relevant to microevolutionary responses to environmental change. Unfortunately, quantitative genetic approaches have one major drawback – they cannot identify the actual genes responsible for genetic variation. Therefore, it is impossible to link evolutionary responses to a changing environment to molecular genetic variation, making our picture of the process incomplete. Many of the best long-term studies have been conducted in passerine birds. Unfortunately genomics resources are only available for two model avian species, and are absent for bird species that are studied in the wild. I will fill this gap by exploiting recent advances in genomics technology to sequence the entire transcriptome of the longest running study of wild birds – the great tit population in Wytham Woods, Oxford. Having identified most of the sequence variation in the great tit transcriptome, I will then genotype all birds for whom phenotype records and blood samples are available This will be, by far, the largest phenotype-genotype dataset of any free-living vertebrate population. I will then use gene mapping techniques to identify genes and genomic regions responsible for variation in a number of key traits such as lifetime recruitment, clutch size and breeding/laying date. This will result in a greater understanding, at the molecular level, how microevolutionary change can arise (or be constrained).
Max ERC Funding
1 560 770 €
Duration
Start date: 2008-10-01, End date: 2014-06-30
Project acronym AXOGLIA
Project The role of myelinating glia in preserving axon function
Researcher (PI) Klaus-Armin Nave
Host Institution (HI) MAX-PLANCK-GESELLSCHAFT ZUR FORDERUNG DER WISSENSCHAFTEN EV
Call Details Advanced Grant (AdG), LS5, ERC-2010-AdG_20100317
Summary In the human brain, the 'bottleneck' of neuronal integrity are long axonal projections, which are often the first to degenerate in neuro-psychiatric diseases. We have discovered in mice that oligodendrocytes and Schwann cells are not only essential for the formation of myelin, but also for the functional integrity of axons and their long-term survival. However, the underlying molecular mechanisms have remained obscure. We propose to use experimental mouse genetics to study neuron-glia interactions and to identify axonal signals that control the normal behaviour of myelinating oligodendrocytes. We will then test our hypothesis that axons require oligodendrocytes not only for myelination, but also for the metabolic support of impulse propagation and fast axonal transport. Based on striking pilot observations, we will analyze the mechanisms by which ensheathing glial cells respond to axonal distress and ask in vivo whether they provide glycolysis end products to axonal mitochondria for energy production ('lactate shuttle'). We will also investigate whether myelin lipids are a readily accessible energy store in glia and explore a speculative hypothesis that N-acetyl aspartate is an aspartate-based shuttle of acetyl-CoA residues. If this proposal is successful, we will begin to understand the true function of oligodendrocytes in endogenous neuroprotection and as bystanders of neuronal disease and normal brain aging. This would initiate a paradigm shift for the role of myelinating glial cells, and could open the door for novel therapeutic strategies in a broad range of neurodegenerative diseases, which pose a major burden on the EC health care system.
Summary
In the human brain, the 'bottleneck' of neuronal integrity are long axonal projections, which are often the first to degenerate in neuro-psychiatric diseases. We have discovered in mice that oligodendrocytes and Schwann cells are not only essential for the formation of myelin, but also for the functional integrity of axons and their long-term survival. However, the underlying molecular mechanisms have remained obscure. We propose to use experimental mouse genetics to study neuron-glia interactions and to identify axonal signals that control the normal behaviour of myelinating oligodendrocytes. We will then test our hypothesis that axons require oligodendrocytes not only for myelination, but also for the metabolic support of impulse propagation and fast axonal transport. Based on striking pilot observations, we will analyze the mechanisms by which ensheathing glial cells respond to axonal distress and ask in vivo whether they provide glycolysis end products to axonal mitochondria for energy production ('lactate shuttle'). We will also investigate whether myelin lipids are a readily accessible energy store in glia and explore a speculative hypothesis that N-acetyl aspartate is an aspartate-based shuttle of acetyl-CoA residues. If this proposal is successful, we will begin to understand the true function of oligodendrocytes in endogenous neuroprotection and as bystanders of neuronal disease and normal brain aging. This would initiate a paradigm shift for the role of myelinating glial cells, and could open the door for novel therapeutic strategies in a broad range of neurodegenerative diseases, which pose a major burden on the EC health care system.
Max ERC Funding
2 477 800 €
Duration
Start date: 2011-04-01, End date: 2016-03-31
Project acronym AXONENDO
Project Endosomal control of local protein synthesis in axons
Researcher (PI) Jean-Michel Cioni
Host Institution (HI) OSPEDALE SAN RAFFAELE SRL
Call Details Starting Grant (StG), LS5, ERC-2019-STG
Summary Neurons are morphologically complex cells that rely on highly compartmentalized signaling to coordinate cellular functions. The endocytic pathway is a crucial trafficking route by which neurons integrate, spatially process and transfer information. Endosomal trafficking in axons and dendrites ensures that required molecules and signaling complexes are present where and when they are functionally needed thus fulfilling essential roles in neuronal physiology. Our recent work has revealed the presence of mRNAs and ribosomes on endosomes in axons, raising the exciting possibility that these motile organelles also directly modulate the local proteome by controlling de novo protein synthesis. However, the mechanisms by which endosomes regulate mRNA translation in neurons is unknown. Moreover, the roles of endosome-mediated control of protein synthesis in neuronal development and function have not been investigated. Here, we propose to bridge this knowledge gap by elucidating links between the endocytic pathway and local protein synthesis in neurons, focusing on their functional relationship in axons. By combining genome-wide analysis, genetic tools, state-of-the-art imaging techniques and the use of Xenopus and mouse vertebrate models, we plan to address the following fundamental questions: (i) What are the mRNAs associated with endosomes and does endosomal trafficking regulate their axonal localization? (ii) Does the endocytic pathway mediate the selective translation of axonal mRNAs in response to extracellular factors? (iii) What are the endosome-associated RNA-binding proteins, and what is the effect of perturbing these associations on axonal development and maintenance in vivo? (iv) Does impaired endosomal regulation of axonal mRNA localization and translation cause axonopathies? Answering these questions will set strong foundations for this new area of research and can provide a new angle in our comprehension of neuropathies in need of novel therapeutic strategies.
Summary
Neurons are morphologically complex cells that rely on highly compartmentalized signaling to coordinate cellular functions. The endocytic pathway is a crucial trafficking route by which neurons integrate, spatially process and transfer information. Endosomal trafficking in axons and dendrites ensures that required molecules and signaling complexes are present where and when they are functionally needed thus fulfilling essential roles in neuronal physiology. Our recent work has revealed the presence of mRNAs and ribosomes on endosomes in axons, raising the exciting possibility that these motile organelles also directly modulate the local proteome by controlling de novo protein synthesis. However, the mechanisms by which endosomes regulate mRNA translation in neurons is unknown. Moreover, the roles of endosome-mediated control of protein synthesis in neuronal development and function have not been investigated. Here, we propose to bridge this knowledge gap by elucidating links between the endocytic pathway and local protein synthesis in neurons, focusing on their functional relationship in axons. By combining genome-wide analysis, genetic tools, state-of-the-art imaging techniques and the use of Xenopus and mouse vertebrate models, we plan to address the following fundamental questions: (i) What are the mRNAs associated with endosomes and does endosomal trafficking regulate their axonal localization? (ii) Does the endocytic pathway mediate the selective translation of axonal mRNAs in response to extracellular factors? (iii) What are the endosome-associated RNA-binding proteins, and what is the effect of perturbing these associations on axonal development and maintenance in vivo? (iv) Does impaired endosomal regulation of axonal mRNA localization and translation cause axonopathies? Answering these questions will set strong foundations for this new area of research and can provide a new angle in our comprehension of neuropathies in need of novel therapeutic strategies.
Max ERC Funding
1 499 563 €
Duration
Start date: 2020-09-01, End date: 2025-08-31
