Project acronym BRAINGAIN
Project NOVEL STRATEGIES FOR BRAIN REGENERATION
Researcher (PI) Andras Simon
Host Institution (HI) KAROLINSKA INSTITUTET
Call Details Starting Grant (StG), LS3, ERC-2011-StG_20101109
Summary In contrast to mammals, newts possess exceptional capacities among vertebrates to rebuild complex structures, such as the brain. Our goal is to bridge the gap in the regenerative outcomes between newts and mammals. My group has made significant contributions towards this goal. We created a novel experimental system, which recapitulates central features of Parkinson’s disease in newts, and provides a unique model for understanding regeneration in the adult midbrain. We showed an unexpected but key feature of the newt brain that it is akin to the mammalian brain in terms of the extent of homeostatic cell turn over, but distinct in terms of its injury response, showing the regenerative capacity of the adult vertebrate brain by activating neurogenesis in normally quiescent regions. Further we established a critical role for the neurotransmitter dopamine in controlling quiescence in the midbrain, thereby preventing neurogenesis during homeostasis and terminating neurogenesis once the correct number of neurons has been produced during regeneration. Here we aim to identify key molecular pathways that regulate adult neurogenesis, to define lineage relationships between neuronal stem and progenitor cells, and to identify essential differences between newts and mammals. We will combine pharmacological modulation of neurotransmitter signaling with extensive cellular fate mapping approaches, and molecular manipulations. Ultimately we will test hypotheses derived from newt studies with mammalian systems including newt/mouse cross species complementation approaches. We expect that our findings will provide new regenerative strategies, and reveal fundamental aspects of cell fate determination, tissue growth, and tissue maintenance in normal and pathological conditions.
Summary
In contrast to mammals, newts possess exceptional capacities among vertebrates to rebuild complex structures, such as the brain. Our goal is to bridge the gap in the regenerative outcomes between newts and mammals. My group has made significant contributions towards this goal. We created a novel experimental system, which recapitulates central features of Parkinson’s disease in newts, and provides a unique model for understanding regeneration in the adult midbrain. We showed an unexpected but key feature of the newt brain that it is akin to the mammalian brain in terms of the extent of homeostatic cell turn over, but distinct in terms of its injury response, showing the regenerative capacity of the adult vertebrate brain by activating neurogenesis in normally quiescent regions. Further we established a critical role for the neurotransmitter dopamine in controlling quiescence in the midbrain, thereby preventing neurogenesis during homeostasis and terminating neurogenesis once the correct number of neurons has been produced during regeneration. Here we aim to identify key molecular pathways that regulate adult neurogenesis, to define lineage relationships between neuronal stem and progenitor cells, and to identify essential differences between newts and mammals. We will combine pharmacological modulation of neurotransmitter signaling with extensive cellular fate mapping approaches, and molecular manipulations. Ultimately we will test hypotheses derived from newt studies with mammalian systems including newt/mouse cross species complementation approaches. We expect that our findings will provide new regenerative strategies, and reveal fundamental aspects of cell fate determination, tissue growth, and tissue maintenance in normal and pathological conditions.
Max ERC Funding
1 500 000 €
Duration
Start date: 2012-02-01, End date: 2017-01-31
Project acronym DYNACOM
Project From Genome Integrity to Genome Plasticity:
Dynamic Complexes Controlling Once per Cell Cycle Replication
Researcher (PI) Zoi Lygerou
Host Institution (HI) PANEPISTIMIO PATRON
Call Details Starting Grant (StG), LS3, ERC-2011-StG_20101109
Summary Accurate genome duplication is controlled by multi-subunit protein complexes which associate with chromatin and dictate when and where replication should take place. Dynamic changes in these complexes lie at the heart of their ability to ensure the maintenance of genomic integrity. Defects in origin bound complexes lead to re-replication of the genome across evolution, have been linked to DNA-replication stress and may predispose for gene amplification events. Such genomic aberrations are central to malignant transformation.
We wish to understand how once per cell cycle replication is normally controlled within the context of the living cell and how defects in this control may result in loss of genome integrity and provide genome plasticity. To this end, live cell imaging in human cells in culture will be combined with genetic studies in fission yeast and modelling and in silico analysis.
The proposed research aims to:
1. Decipher the regulatory mechanisms which act in time and space to ensure once per cell cycle replication within living cells and how they may be affected by system aberrations, using functional live cell imaging.
2. Test whether aberrations in the licensing system may provide a selective advantage, through amplification of multiple genomic loci. To this end, a natural selection experiment will be set up in fission yeast .
3. Investigate how rereplication takes place along the genome in single cells. Is there heterogeneity amongst a population, leading to a plethora of different genotypes? In silico analysis of full genome DNA rereplication will be combined to single cell analysis in fission yeast.
4. Assess the relevance of our findings for gene amplification events in cancer. Does ectopic expression of human Cdt1/Cdc6 in cancer cells enhance drug resistance through gene amplification?
Our findings are expected to offer novel insight into mechanisms underlying cancer development and progression.
Summary
Accurate genome duplication is controlled by multi-subunit protein complexes which associate with chromatin and dictate when and where replication should take place. Dynamic changes in these complexes lie at the heart of their ability to ensure the maintenance of genomic integrity. Defects in origin bound complexes lead to re-replication of the genome across evolution, have been linked to DNA-replication stress and may predispose for gene amplification events. Such genomic aberrations are central to malignant transformation.
We wish to understand how once per cell cycle replication is normally controlled within the context of the living cell and how defects in this control may result in loss of genome integrity and provide genome plasticity. To this end, live cell imaging in human cells in culture will be combined with genetic studies in fission yeast and modelling and in silico analysis.
The proposed research aims to:
1. Decipher the regulatory mechanisms which act in time and space to ensure once per cell cycle replication within living cells and how they may be affected by system aberrations, using functional live cell imaging.
2. Test whether aberrations in the licensing system may provide a selective advantage, through amplification of multiple genomic loci. To this end, a natural selection experiment will be set up in fission yeast .
3. Investigate how rereplication takes place along the genome in single cells. Is there heterogeneity amongst a population, leading to a plethora of different genotypes? In silico analysis of full genome DNA rereplication will be combined to single cell analysis in fission yeast.
4. Assess the relevance of our findings for gene amplification events in cancer. Does ectopic expression of human Cdt1/Cdc6 in cancer cells enhance drug resistance through gene amplification?
Our findings are expected to offer novel insight into mechanisms underlying cancer development and progression.
Max ERC Funding
1 531 000 €
Duration
Start date: 2012-02-01, End date: 2017-01-31
Project acronym InPhoTime
Project Insect Photoperiodic Timer
Researcher (PI) David DOLEZEL
Host Institution (HI) Biologicke centrum AV CR, v. v. i.
Call Details Consolidator Grant (CoG), LS3, ERC-2016-COG
Summary Daylength measuring devices such as the photoperiodic timer enable animals to anticipate and thus survive adverse seasons. This ability has contributed to the great success of insects living in temperate regions. Yet the basis of photoperiodic sensing remains elusive, because of the lack of suitable genetic models expressing photoperiod-dependent seasonal phenotypes. We have developed the linden bug, Pyrrhocoris apterus, into a genetically tractable model with a robust, photoperiod-dependent reproductive arrest (diapause). With the available tools, this insect has become ideal for deciphering the regulation of seasonality. The project has 3 clear and ambitious objectives: 1). Our goal is to define the molecular and anatomical bases of the photoperiodic timer. To achieve this, we propose to identify photoperiodic timer genes, genes regulating input to the timer, and early output markers, through an RNA interference screen(s). To define the molecular mechanism of the timer, we will employ genome editing to precisely alter properties of the key players. 2). Next, we will combine techniques of neuronal backfilling, in-vivo fluorescent reporters, and microsurgery to define the photoperiodic timer anatomically and to examine its spatial relationship to the circadian clock in the insect brain. 3). We will exploit the great natural geographic variability of photoperiodic timing in P. apterus to explore its genetic basis. Genetic variants correlating with phenotypic differences will be causally tested by genome editing within the original genetic backgrounds. Both the established and the innovative strategies provide a complementary approach to the first molecular characterization of the seasonal photoperiodic timer in insects. The proposed research aspires to explain mechanisms underlying the critical physiological adaptation to changing seasons. Deciphering mechanisms underpinning widespread adaptation might bring general implications for environment-friendly pest control.
Summary
Daylength measuring devices such as the photoperiodic timer enable animals to anticipate and thus survive adverse seasons. This ability has contributed to the great success of insects living in temperate regions. Yet the basis of photoperiodic sensing remains elusive, because of the lack of suitable genetic models expressing photoperiod-dependent seasonal phenotypes. We have developed the linden bug, Pyrrhocoris apterus, into a genetically tractable model with a robust, photoperiod-dependent reproductive arrest (diapause). With the available tools, this insect has become ideal for deciphering the regulation of seasonality. The project has 3 clear and ambitious objectives: 1). Our goal is to define the molecular and anatomical bases of the photoperiodic timer. To achieve this, we propose to identify photoperiodic timer genes, genes regulating input to the timer, and early output markers, through an RNA interference screen(s). To define the molecular mechanism of the timer, we will employ genome editing to precisely alter properties of the key players. 2). Next, we will combine techniques of neuronal backfilling, in-vivo fluorescent reporters, and microsurgery to define the photoperiodic timer anatomically and to examine its spatial relationship to the circadian clock in the insect brain. 3). We will exploit the great natural geographic variability of photoperiodic timing in P. apterus to explore its genetic basis. Genetic variants correlating with phenotypic differences will be causally tested by genome editing within the original genetic backgrounds. Both the established and the innovative strategies provide a complementary approach to the first molecular characterization of the seasonal photoperiodic timer in insects. The proposed research aspires to explain mechanisms underlying the critical physiological adaptation to changing seasons. Deciphering mechanisms underpinning widespread adaptation might bring general implications for environment-friendly pest control.
Max ERC Funding
2 000 000 €
Duration
Start date: 2017-04-01, End date: 2022-03-31
Project acronym Neurogenesis
Project Exploration and promotion of neurogenesis in the adult brain
Researcher (PI) Jonas FRISÉN
Host Institution (HI) KAROLINSKA INSTITUTET
Call Details Advanced Grant (AdG), LS3, ERC-2015-AdG
Summary It is now well established that new neurons are added to certain regions of the adult brain. There is today considerable interest in the development of regenerative therapies based on modulating endogenous neurogenesis, but it is necessary to better understand these events to assess whether this is rational and realistic.
This application takes its initiation in two recent discoveries that we have made: that astrocytes in the mouse striatum give rise to new neurons after stroke or inhibition of Notch signaling (Magnusson et al., Science, 2014) and that neurogenesis is a continuous process in the human striatum throughout adulthood (Ernst et al., Cell, 2014). We propose to characterize the molecular regulation of neurogenesis from striatal astrocytes in detail, and compare these astrocytes with those in other regions to understand why striatal astrocytes are uniquely neurogenic and whether astrocytes in other parts of the brain can be induced to give rise to new neurons. We will, moreover, assess the role of integration of new neurons in the striatal circuitry by inducing neurogenesis in the striatum in adult mice by blocking Notch signaling or by inducing stroke and modulate the activity of the new neurons by optogenetics and chemogenetics. We will, furthermore, study whether striatal neurogenesis is altered in human neurological diseases by retrospective birth dating by measuring the integration of 14C from nuclear bomb tests. We will assess whether inducing striatal neurogenesis in corresponding mouse models of neurological diseases has therapeutic potential.
This project will elucidate the molecular regulation of neurogenesis from astrocytes and the neurogenic potential of astrocytes in different parts of the brain, reveal the role of new neurons in the striatum, answer whether striatal neurogenesis is altered in common neurological conditions in humans and reveal whether inducing striatal neurogenesis may have therapeutic potential.
Summary
It is now well established that new neurons are added to certain regions of the adult brain. There is today considerable interest in the development of regenerative therapies based on modulating endogenous neurogenesis, but it is necessary to better understand these events to assess whether this is rational and realistic.
This application takes its initiation in two recent discoveries that we have made: that astrocytes in the mouse striatum give rise to new neurons after stroke or inhibition of Notch signaling (Magnusson et al., Science, 2014) and that neurogenesis is a continuous process in the human striatum throughout adulthood (Ernst et al., Cell, 2014). We propose to characterize the molecular regulation of neurogenesis from striatal astrocytes in detail, and compare these astrocytes with those in other regions to understand why striatal astrocytes are uniquely neurogenic and whether astrocytes in other parts of the brain can be induced to give rise to new neurons. We will, moreover, assess the role of integration of new neurons in the striatal circuitry by inducing neurogenesis in the striatum in adult mice by blocking Notch signaling or by inducing stroke and modulate the activity of the new neurons by optogenetics and chemogenetics. We will, furthermore, study whether striatal neurogenesis is altered in human neurological diseases by retrospective birth dating by measuring the integration of 14C from nuclear bomb tests. We will assess whether inducing striatal neurogenesis in corresponding mouse models of neurological diseases has therapeutic potential.
This project will elucidate the molecular regulation of neurogenesis from astrocytes and the neurogenic potential of astrocytes in different parts of the brain, reveal the role of new neurons in the striatum, answer whether striatal neurogenesis is altered in common neurological conditions in humans and reveal whether inducing striatal neurogenesis may have therapeutic potential.
Max ERC Funding
2 500 000 €
Duration
Start date: 2016-10-01, End date: 2021-09-30
Project acronym PAGE
Project The role of mRNA-processing bodies in ageing
Researcher (PI) Popi Syntichaki
Host Institution (HI) IDRYMA IATROVIOLOGIKON EREUNON AKADEMIAS ATHINON
Call Details Starting Grant (StG), LS3, ERC-2007-StG
Summary Recently, we and others have revealed that, in the nematode Caenorhabditis elegans, reduction of protein synthesis rates in somatic cells extends lifespan. Based on this, we postulate that the molecular factors and mechanisms that control the mRNA metabolism in post-mitotic cells are critical determinants of ageing. This project will validate this hypothesis using C. elegans as main model system, but parallel studies in Saccharomyces cerevisiae and Drosophila melanogaster will prove the conservation of our observations. The cellular factors involved in mRNA metabolism (degradation/storage) are localized at specific particles in the cytoplasm of all eukaryotic cells, termed mRNA processing (P) bodies. Additionally, stress granules are cytoplasmic sites of mRNA-metabolism that are formed under stress conditions in mammalian cells. The objectives of this project include: -Monitoring of both P bodies and stress granules in adult worms and characterization of the age-related alterations in their profile, by immunostaining and real-time fluorescence imaging -Direct alterations in the expression of genes encoding factors of each particle in wild-type worms and analysis of the effects on lifespan and stress resistance -Comparison of the age-related changes in the profile of P bodies and stress granules between wild-type and long- or short-lived mutant worms -Direct alterations in the expression of genes encoding factors of each particle in worms with altered lifespan and investigation of the effects on lifespan and stress resistance -Observation of the age-related alterations in the profile of P bodies in yeast and flies, both in wild-type and long-lived strains. The rationale for this project is to provide insight into the modulation of ageing and stress resistance at the level of mRNA metabolism, which is a yet unexplored field of the biology of ageing and global stress response.
Summary
Recently, we and others have revealed that, in the nematode Caenorhabditis elegans, reduction of protein synthesis rates in somatic cells extends lifespan. Based on this, we postulate that the molecular factors and mechanisms that control the mRNA metabolism in post-mitotic cells are critical determinants of ageing. This project will validate this hypothesis using C. elegans as main model system, but parallel studies in Saccharomyces cerevisiae and Drosophila melanogaster will prove the conservation of our observations. The cellular factors involved in mRNA metabolism (degradation/storage) are localized at specific particles in the cytoplasm of all eukaryotic cells, termed mRNA processing (P) bodies. Additionally, stress granules are cytoplasmic sites of mRNA-metabolism that are formed under stress conditions in mammalian cells. The objectives of this project include: -Monitoring of both P bodies and stress granules in adult worms and characterization of the age-related alterations in their profile, by immunostaining and real-time fluorescence imaging -Direct alterations in the expression of genes encoding factors of each particle in wild-type worms and analysis of the effects on lifespan and stress resistance -Comparison of the age-related changes in the profile of P bodies and stress granules between wild-type and long- or short-lived mutant worms -Direct alterations in the expression of genes encoding factors of each particle in worms with altered lifespan and investigation of the effects on lifespan and stress resistance -Observation of the age-related alterations in the profile of P bodies in yeast and flies, both in wild-type and long-lived strains. The rationale for this project is to provide insight into the modulation of ageing and stress resistance at the level of mRNA metabolism, which is a yet unexplored field of the biology of ageing and global stress response.
Max ERC Funding
1 080 000 €
Duration
Start date: 2008-09-01, End date: 2014-08-31
Project acronym QUALIAGE
Project Spatial protein quality control and its links to aging, proteotoxicity, and polarity
Researcher (PI) Lars Bertil Thomas Nyström
Host Institution (HI) GOETEBORGS UNIVERSITET
Call Details Advanced Grant (AdG), LS3, ERC-2010-AdG_20100317
Summary Propagation of a species requires periodic cell renewal to avoid clonal senescence. My
laboratory has described a new mechanism for such cell renewal in yeast, in which damaged
protein aggregates are transported out of the daughter buds along actin cables to preserve
youthfulness. Such spatial protein quality control (SQC) is a Sir2p-dependent process and by establishing the global genetic interaction network of SIR2, we identified the
polarisome as the machinery required for mitotic segregation and translocation of protein
aggregates. In addition, we found that the fusion of smaller aggregates into large inclusion
bodies, a process that has been suggested to reduce the toxicity of such aggregates, requires
actin cables and their nucleation at the septin ring. Sir2p controls damage segregation by
affecting deacetylation and the activity of the chaperonin CCT, enhancing actin folding and
polymerization. Considering that CCT has been implicated in mitigating
aggregation/toxicity of polyglutamine proteins, e.g. huntingtin, and that actin cables is
affecting formation, fusion, and resolution of aggregates, we hypothesize that CCT
deacetylation may underlie Sirt1¿s (mammalian orthologues of Sir2p) documented beneficial
effects in several neurodegenerative disorders caused by proteotoxic aggregates. This project
is aimed at approaching this hypothesis and to elucidate, on a genome-wide scale, how the
cell tether, sort, fuse, and detoxify aggregates with the help of CCT, actin cables, and the
polarity machinery. This will be accomplished by combining the power of synthetic genetic
array analysis, high-content imaging, genome wide proximity ligand assays, and microfluidics.
Using such approaches, the project seeks to decipher the machineries of the spatial quality
control network as a means to identify new therapeutic targets that may retard or postpone
the development of age-related maladies, including neurodegenerative disorders.
Summary
Propagation of a species requires periodic cell renewal to avoid clonal senescence. My
laboratory has described a new mechanism for such cell renewal in yeast, in which damaged
protein aggregates are transported out of the daughter buds along actin cables to preserve
youthfulness. Such spatial protein quality control (SQC) is a Sir2p-dependent process and by establishing the global genetic interaction network of SIR2, we identified the
polarisome as the machinery required for mitotic segregation and translocation of protein
aggregates. In addition, we found that the fusion of smaller aggregates into large inclusion
bodies, a process that has been suggested to reduce the toxicity of such aggregates, requires
actin cables and their nucleation at the septin ring. Sir2p controls damage segregation by
affecting deacetylation and the activity of the chaperonin CCT, enhancing actin folding and
polymerization. Considering that CCT has been implicated in mitigating
aggregation/toxicity of polyglutamine proteins, e.g. huntingtin, and that actin cables is
affecting formation, fusion, and resolution of aggregates, we hypothesize that CCT
deacetylation may underlie Sirt1¿s (mammalian orthologues of Sir2p) documented beneficial
effects in several neurodegenerative disorders caused by proteotoxic aggregates. This project
is aimed at approaching this hypothesis and to elucidate, on a genome-wide scale, how the
cell tether, sort, fuse, and detoxify aggregates with the help of CCT, actin cables, and the
polarity machinery. This will be accomplished by combining the power of synthetic genetic
array analysis, high-content imaging, genome wide proximity ligand assays, and microfluidics.
Using such approaches, the project seeks to decipher the machineries of the spatial quality
control network as a means to identify new therapeutic targets that may retard or postpone
the development of age-related maladies, including neurodegenerative disorders.
Max ERC Funding
2 371 262 €
Duration
Start date: 2011-06-01, End date: 2016-05-31
Project acronym Triploid Block
Project Mechanisms of polyploidy-mediated postzygotic reproductive isolation
Researcher (PI) Claudia Köhler
Host Institution (HI) SVERIGES LANTBRUKSUNIVERSITET
Call Details Starting Grant (StG), LS3, ERC-2011-StG_20101109
Summary Polyploidization is a widespread phenomenon among plants and is considered a major speciation mechanism. Before becoming evolutionary successful, newly formed polyploids often have to overcome fertility bottlenecks, because mating with partners of lower ploidy causes incompatibilities in the endosperm leading to the formation of mainly non-viable progeny. This reproductive barrier is called the triploid block. Nevertheless, the most frequent route to polyploid formation is probably through unreduced gametes, suggesting that the triploid block can be overcome. Recent work from our laboratory uncovered a genetic pathway leading to unreduced gamete formation at high frequency and revealed that the triploid block is mainly caused by malfunction of Polycomb group (PcG) proteins. PcG proteins are evolutionary conserved proteins, which assemble into multimeric complexes with chromatin-modifying enzymatic activity, implicating epigenetic regulatory mechanisms as an important element of speciation. Here, I propose to unravel the underlying molecular mechanism(s) of the triploid block by identifying the responsible genes causing endosperm failure upon deregulation and their mechanism of regulation in response to interploidy crosses. I also plan to investigate whether genes that contribute to the triploid block are as well responsible for establishing interspecies incompatibilities within the Arabidopsis genus. This project will combine genetics, genomics and epigenomics and will make extensive use of knowledge and tools that we have been established in my laboratory over the recent years, making it likely that the proposed objectives can be achieved. The results of this project will be of interest to a broad scientific community, including biologists with a strong interest in epigenetic mechanisms as well as ecologists interested to understand mechanisms of plant speciation.
Summary
Polyploidization is a widespread phenomenon among plants and is considered a major speciation mechanism. Before becoming evolutionary successful, newly formed polyploids often have to overcome fertility bottlenecks, because mating with partners of lower ploidy causes incompatibilities in the endosperm leading to the formation of mainly non-viable progeny. This reproductive barrier is called the triploid block. Nevertheless, the most frequent route to polyploid formation is probably through unreduced gametes, suggesting that the triploid block can be overcome. Recent work from our laboratory uncovered a genetic pathway leading to unreduced gamete formation at high frequency and revealed that the triploid block is mainly caused by malfunction of Polycomb group (PcG) proteins. PcG proteins are evolutionary conserved proteins, which assemble into multimeric complexes with chromatin-modifying enzymatic activity, implicating epigenetic regulatory mechanisms as an important element of speciation. Here, I propose to unravel the underlying molecular mechanism(s) of the triploid block by identifying the responsible genes causing endosperm failure upon deregulation and their mechanism of regulation in response to interploidy crosses. I also plan to investigate whether genes that contribute to the triploid block are as well responsible for establishing interspecies incompatibilities within the Arabidopsis genus. This project will combine genetics, genomics and epigenomics and will make extensive use of knowledge and tools that we have been established in my laboratory over the recent years, making it likely that the proposed objectives can be achieved. The results of this project will be of interest to a broad scientific community, including biologists with a strong interest in epigenetic mechanisms as well as ecologists interested to understand mechanisms of plant speciation.
Max ERC Funding
1 447 596 €
Duration
Start date: 2011-10-01, End date: 2016-09-30
