Project acronym APOSITE
Project Apoptotic foci: composition, structure and dynamics
Researcher (PI) Ana GARCIA SAEZ
Host Institution (HI) UNIVERSITAET ZU KOELN
Call Details Consolidator Grant (CoG), LS3, ERC-2018-COG
Summary Apoptotic cell death is essential for development, immune function or tissue homeostasis, and it is often deregulated in disease. Mitochondrial outer membrane permeabilization (MOMP) is central for apoptosis execution and plays a key role in its inflammatory outcome. Knowing the architecture of the macromolecular machineries mediating MOMP is crucial for understanding their function and for the clinical use of apoptosis.
Our recent work reveals that Bax and Bak dimers form distinct line, arc and ring assemblies at specific apoptotic foci to mediate MOMP. However, the molecular structure and mechanisms controlling the spatiotemporal formation and range of action of the apoptotic foci are missing. To address this fundamental gap in our knowledge, we aim to unravel the composition, dynamics and structure of apoptotic foci and to understand how they are integrated to orchestrate function. We will reach this goal by building on our expertise in cell death and cutting-edge imaging and by developing a new analytical pipeline to:
1) Identify the composition of apoptotic foci using in situ proximity-dependent labeling and extraction of near-native Bax/Bak membrane complexes coupled to mass spectrometry.
2) Define their contribution to apoptosis and its immunogenicity and establish their assembly dynamics to correlate it with apoptosis progression by live cell imaging.
3) Determine the stoichiometry and structural organization of the apoptotic foci by combining single molecule fluorescence and advanced electron microscopies.
This multidisciplinary approach offers high chances to solve the long-standing question of how Bax and Bak mediate MOMP. APOSITE will provide textbook knowledge of the mitochondrial contribution to cell death and inflammation. The implementation of this new analytical framework will open novel research avenues in membrane and organelle biology. Ultimately, understanding of Bax and Bak structure/function will help develop apoptosis modulators for medicine.
Summary
Apoptotic cell death is essential for development, immune function or tissue homeostasis, and it is often deregulated in disease. Mitochondrial outer membrane permeabilization (MOMP) is central for apoptosis execution and plays a key role in its inflammatory outcome. Knowing the architecture of the macromolecular machineries mediating MOMP is crucial for understanding their function and for the clinical use of apoptosis.
Our recent work reveals that Bax and Bak dimers form distinct line, arc and ring assemblies at specific apoptotic foci to mediate MOMP. However, the molecular structure and mechanisms controlling the spatiotemporal formation and range of action of the apoptotic foci are missing. To address this fundamental gap in our knowledge, we aim to unravel the composition, dynamics and structure of apoptotic foci and to understand how they are integrated to orchestrate function. We will reach this goal by building on our expertise in cell death and cutting-edge imaging and by developing a new analytical pipeline to:
1) Identify the composition of apoptotic foci using in situ proximity-dependent labeling and extraction of near-native Bax/Bak membrane complexes coupled to mass spectrometry.
2) Define their contribution to apoptosis and its immunogenicity and establish their assembly dynamics to correlate it with apoptosis progression by live cell imaging.
3) Determine the stoichiometry and structural organization of the apoptotic foci by combining single molecule fluorescence and advanced electron microscopies.
This multidisciplinary approach offers high chances to solve the long-standing question of how Bax and Bak mediate MOMP. APOSITE will provide textbook knowledge of the mitochondrial contribution to cell death and inflammation. The implementation of this new analytical framework will open novel research avenues in membrane and organelle biology. Ultimately, understanding of Bax and Bak structure/function will help develop apoptosis modulators for medicine.
Max ERC Funding
2 000 000 €
Duration
Start date: 2019-04-01, End date: 2024-03-31
Project acronym CELLONGATE
Project Unraveling the molecular network that drives cell growth in plants
Researcher (PI) Matyas FENDRYCH
Host Institution (HI) UNIVERZITA KARLOVA
Call Details Starting Grant (StG), LS3, ERC-2018-STG
Summary Plants differ strikingly from animals by the almost total absence of cell migration in their development. Plants build their bodies using a hydrostatic skeleton that consists of pressurized cells encased by a cell wall. Consequently, plant cells cannot migrate and must sculpture their bodies by orientation of cell division and precise regulation of cell growth. Cell growth depends on the balance between internal cell pressure – turgor, and strength of the cell wall. Cell growth is under a strict developmental control, which is exemplified in the Arabidopsis thaliana root tip, where massive cell elongation occurs in a defined spatio-temporal developmental window. Despite the immobility of their cells, plant organs move to optimize light and nutrient acquisition and to orient their bodies along the gravity vector. These movements depend on differential regulation of cell elongation across the organ, and on response to the phytohormone auxin. Even though the control of cell growth is in the epicenter of plant development, protein networks steering the developmental growth onset, coordination and termination remain elusive. Similarly, although auxin is the central regulator of growth, the molecular mechanism of its effect on root growth is unknown. In this project, I will establish a unique microscopy setup for high spatio-temporal resolution live-cell imaging equipped with a microfluidic lab-on-chip platform optimized for growing roots, to enable analysis and manipulation of root growth physiology. I will use developmental gradients in the root to discover genes that steer cellular growth, by correlating transcriptome profiles of individual cell types with the cell size. In parallel, I will exploit the auxin effect on root to unravel molecular mechanisms that control cell elongation. Finally, I am going to combine the live-cell imaging methodology with the gene discovery approaches to chart a dynamic spatio-temporal physiological map of a growing Arabidopsis root.
Summary
Plants differ strikingly from animals by the almost total absence of cell migration in their development. Plants build their bodies using a hydrostatic skeleton that consists of pressurized cells encased by a cell wall. Consequently, plant cells cannot migrate and must sculpture their bodies by orientation of cell division and precise regulation of cell growth. Cell growth depends on the balance between internal cell pressure – turgor, and strength of the cell wall. Cell growth is under a strict developmental control, which is exemplified in the Arabidopsis thaliana root tip, where massive cell elongation occurs in a defined spatio-temporal developmental window. Despite the immobility of their cells, plant organs move to optimize light and nutrient acquisition and to orient their bodies along the gravity vector. These movements depend on differential regulation of cell elongation across the organ, and on response to the phytohormone auxin. Even though the control of cell growth is in the epicenter of plant development, protein networks steering the developmental growth onset, coordination and termination remain elusive. Similarly, although auxin is the central regulator of growth, the molecular mechanism of its effect on root growth is unknown. In this project, I will establish a unique microscopy setup for high spatio-temporal resolution live-cell imaging equipped with a microfluidic lab-on-chip platform optimized for growing roots, to enable analysis and manipulation of root growth physiology. I will use developmental gradients in the root to discover genes that steer cellular growth, by correlating transcriptome profiles of individual cell types with the cell size. In parallel, I will exploit the auxin effect on root to unravel molecular mechanisms that control cell elongation. Finally, I am going to combine the live-cell imaging methodology with the gene discovery approaches to chart a dynamic spatio-temporal physiological map of a growing Arabidopsis root.
Max ERC Funding
1 498 750 €
Duration
Start date: 2019-01-01, End date: 2023-12-31
Project acronym CellularBiographies
Project Global views of cell type specification and differentiation
Researcher (PI) Alexander Schier
Host Institution (HI) UNIVERSITAT BASEL
Call Details Advanced Grant (AdG), LS3, ERC-2018-ADG
Summary Each cell in our body has a specific biography that is defined by its pedigree relationship with other cells (lineage) and by its history of gene expression (trajectory). A fundamental question in cellular and developmental biology has been how the lineage and trajectory of a cell lead to its specification and differentiation. Remarkable progress in genome editing and single-cell sequencing has generated the opportunity to understand this process at global scales and single-cell resolution. We have recently developed methods to reconstruct the cellular ancestry and transcriptional trajectories of cells during embryogenesis. The resulting lineage and trajectory trees can be analyzed to gain comprehensive views of how cellular diversity arises and how differentiation leads to physiologically specialized cell types. To generate such global views of cellular development, we will: 1. Define the cellular diversity and gene expression trajectories during zebrafish embryogenesis and organogenesis. Trajectory trees will be generated from scRNA-seq data and analyzed to reconstruct the gene expression pathways underlying fate specification. 2. Reveal the relationships between lineage and transcriptional trajectories during fate specification. Lineage trees will be generated by marking cells via genome editing and combined with trajectory trees to reveal the cellular paths towards fate specification. 3. Discover the gene expression cascades that remodel cells into physiologically functional types. Cell biological modules will be identified by comparing gene enrichment in differentiation trajectories and reveal the specialized and shared mechanisms of differentiation. These studies will help provide the first comprehensive and global view of the trajectories and lineages underlying vertebrate development. Our focus is on the zebrafish model system, but the data and concepts developed in this project will be applicable to other developmental and cellular systems.
Summary
Each cell in our body has a specific biography that is defined by its pedigree relationship with other cells (lineage) and by its history of gene expression (trajectory). A fundamental question in cellular and developmental biology has been how the lineage and trajectory of a cell lead to its specification and differentiation. Remarkable progress in genome editing and single-cell sequencing has generated the opportunity to understand this process at global scales and single-cell resolution. We have recently developed methods to reconstruct the cellular ancestry and transcriptional trajectories of cells during embryogenesis. The resulting lineage and trajectory trees can be analyzed to gain comprehensive views of how cellular diversity arises and how differentiation leads to physiologically specialized cell types. To generate such global views of cellular development, we will: 1. Define the cellular diversity and gene expression trajectories during zebrafish embryogenesis and organogenesis. Trajectory trees will be generated from scRNA-seq data and analyzed to reconstruct the gene expression pathways underlying fate specification. 2. Reveal the relationships between lineage and transcriptional trajectories during fate specification. Lineage trees will be generated by marking cells via genome editing and combined with trajectory trees to reveal the cellular paths towards fate specification. 3. Discover the gene expression cascades that remodel cells into physiologically functional types. Cell biological modules will be identified by comparing gene enrichment in differentiation trajectories and reveal the specialized and shared mechanisms of differentiation. These studies will help provide the first comprehensive and global view of the trajectories and lineages underlying vertebrate development. Our focus is on the zebrafish model system, but the data and concepts developed in this project will be applicable to other developmental and cellular systems.
Max ERC Funding
2 411 440 €
Duration
Start date: 2020-01-01, End date: 2024-12-31
Project acronym CellularLogistics
Project Cellular Logistics: Form, Formation and Function of the Neuronal Microtubule Cytoskeleton
Researcher (PI) Lukas Christian KAPITEIN
Host Institution (HI) UNIVERSITEIT UTRECHT
Call Details Consolidator Grant (CoG), LS3, ERC-2018-COG
Summary The organization and dynamics of the MT (MT) cytoskeleton underlies the morphology, polarization and division of most cells. The structural polarity of MT determines the directionality of motor proteins, which move selectively towards either the MT plus (most kinesins) or minus end (dynein) to control the transport and positioning of proteins and organelles. Understanding how different cellular MT arrays, such as the mitotic spindle or neuronal MT networks, are built and utilized to ensure proper cellular logistics is a central challenge in cell biology.
Recently, our lab has introduced a new technique, motor-PAINT, to directly resolve MT polarity and the relation between MT orientations, stability and modifications. This revealed that in neurons, the mixed polarity MT network in the dendrites is much more ordered than previously anticipated. MTs with opposite orientations have different properties and are preferred by distinct kinesins, revealing an architectural principle that could explain why different plus-end directed motors move towards distinct destinations. Nevertheless, the mechanisms by which this specialized organization is established and the different ways in which it modulates intracellular transport have remained unknown.
To resolve how cytoskeletal organization guides transport, I propose to explore the form, formation and functioning of the neuronal MT cytoskeleton. We will combine advanced microscopy, molecular biology, and mathematical modelling to: 1) Create a complete 3D map of the dendritic MT cytoskeleton – form. 2) Unravel the mechanisms that establish MT organization in dendrites – formation. 3) Explore how specific MT configurations modulate intracellular transport – function.
This research will uncover key mechanisms of cytoskeletal organization and transport in neurons. In addition, our techniques and concepts will aid understanding intracellular transport in other cellular systems.
Summary
The organization and dynamics of the MT (MT) cytoskeleton underlies the morphology, polarization and division of most cells. The structural polarity of MT determines the directionality of motor proteins, which move selectively towards either the MT plus (most kinesins) or minus end (dynein) to control the transport and positioning of proteins and organelles. Understanding how different cellular MT arrays, such as the mitotic spindle or neuronal MT networks, are built and utilized to ensure proper cellular logistics is a central challenge in cell biology.
Recently, our lab has introduced a new technique, motor-PAINT, to directly resolve MT polarity and the relation between MT orientations, stability and modifications. This revealed that in neurons, the mixed polarity MT network in the dendrites is much more ordered than previously anticipated. MTs with opposite orientations have different properties and are preferred by distinct kinesins, revealing an architectural principle that could explain why different plus-end directed motors move towards distinct destinations. Nevertheless, the mechanisms by which this specialized organization is established and the different ways in which it modulates intracellular transport have remained unknown.
To resolve how cytoskeletal organization guides transport, I propose to explore the form, formation and functioning of the neuronal MT cytoskeleton. We will combine advanced microscopy, molecular biology, and mathematical modelling to: 1) Create a complete 3D map of the dendritic MT cytoskeleton – form. 2) Unravel the mechanisms that establish MT organization in dendrites – formation. 3) Explore how specific MT configurations modulate intracellular transport – function.
This research will uncover key mechanisms of cytoskeletal organization and transport in neurons. In addition, our techniques and concepts will aid understanding intracellular transport in other cellular systems.
Max ERC Funding
2 000 000 €
Duration
Start date: 2019-05-01, End date: 2024-04-30
Project acronym CENGIN
Project Deciphering and engineering centriole assembly
Researcher (PI) Pierre Jörg GÖNCZY
Host Institution (HI) ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE
Call Details Advanced Grant (AdG), LS3, ERC-2018-ADG
Summary Deciphering and engineering the assembly of cellular organelles is a key pursuit in biology. The centriole is an evolutionarily conserved organelle well suited for this goal, and which is crucial for cell signaling, motility and division. The centriole exhibits a striking 9-fold radial symmetry of microtubules around a likewise symmetrical cartwheel containing stacked ring-bearing structures. Components essential for generating this remarkable architecture from alga to man have been identified. A next critical step is to engineer assays to probe the dynamics of centriole assembly with molecular precision to fully understand how these components together build a functional organelle. Our ambitious research proposal aims at taking groundbreaking steps in this direction through four specific aims:
1) Reconstituting cartwheel ring assembly dynamics. We will use high-speed AFM (HS-AFM) to dissect the biophysics of SAS-6 ring polymer dynamics at the root of cartwheel assembly. We will also use HS-AFM to analyze monobodies against SAS-6, as well as engineer surfaces and DNA origamis to further dissect ring assembly.
2) Deciphering ring stacking mechanisms. We will use cryo-ET to identify SAS-6 features that direct stacking of ring structures and set cartwheel height. Moreover, we will develop an HS-AFM stacking assay and a reconstituted stacking assay from human cells.
3) Understanding peripheral element contributions to centriole biogenesis. We will dissect the function of the peripheral centriole pinhead protein Cep135/Bld10p, as well as identify and likewise dissect peripheral A-C linker proteins. Furthermore, we will further engineer the HS-AFM assay to include such peripheral components.
4) Dissecting de novo centriole assembly mechanisms. We will dissect de novo centriole formation in human cells and water fern. We will also explore whether de novo formation involves a phase separation mechanism and repurpose the HS-AFM assay to probe de novo organelle biogenes
Summary
Deciphering and engineering the assembly of cellular organelles is a key pursuit in biology. The centriole is an evolutionarily conserved organelle well suited for this goal, and which is crucial for cell signaling, motility and division. The centriole exhibits a striking 9-fold radial symmetry of microtubules around a likewise symmetrical cartwheel containing stacked ring-bearing structures. Components essential for generating this remarkable architecture from alga to man have been identified. A next critical step is to engineer assays to probe the dynamics of centriole assembly with molecular precision to fully understand how these components together build a functional organelle. Our ambitious research proposal aims at taking groundbreaking steps in this direction through four specific aims:
1) Reconstituting cartwheel ring assembly dynamics. We will use high-speed AFM (HS-AFM) to dissect the biophysics of SAS-6 ring polymer dynamics at the root of cartwheel assembly. We will also use HS-AFM to analyze monobodies against SAS-6, as well as engineer surfaces and DNA origamis to further dissect ring assembly.
2) Deciphering ring stacking mechanisms. We will use cryo-ET to identify SAS-6 features that direct stacking of ring structures and set cartwheel height. Moreover, we will develop an HS-AFM stacking assay and a reconstituted stacking assay from human cells.
3) Understanding peripheral element contributions to centriole biogenesis. We will dissect the function of the peripheral centriole pinhead protein Cep135/Bld10p, as well as identify and likewise dissect peripheral A-C linker proteins. Furthermore, we will further engineer the HS-AFM assay to include such peripheral components.
4) Dissecting de novo centriole assembly mechanisms. We will dissect de novo centriole formation in human cells and water fern. We will also explore whether de novo formation involves a phase separation mechanism and repurpose the HS-AFM assay to probe de novo organelle biogenes
Max ERC Funding
2 500 000 €
Duration
Start date: 2019-09-01, End date: 2024-08-31
Project acronym ChaperoneRegulome
Project ChaperoneRegulome: Understanding cell-type-specificity of chaperone regulation
Researcher (PI) Ritwick SAWARKAR
Host Institution (HI) THE CHANCELLOR MASTERS AND SCHOLARSOF THE UNIVERSITY OF CAMBRIDGE
Call Details Consolidator Grant (CoG), LS3, ERC-2018-COG
Summary Protein misfolding causes devastating health conditions such as neurodegeneration. Although the disease-causing protein is widely expressed, its misfolding occurs only in certain cell-types such as neurons. What governs the susceptibility of some tissues to misfolding is a fundamental question with biomedical relevance.
Molecular chaperones help cellular proteins fold into their native conformation. Despite the generality of their function, chaperones are differentially expressed across various tissues. Moreover exposure to misfolding stress changes chaperone expression in a cell-type-dependent manner. Thus cell-type-specific regulation of chaperones is a major determinant of susceptibility to misfolding. The molecular mechanisms governing chaperone levels in different cell-types are not understood, forming the basis of this proposal. We will take a multidisciplinary approach to address two key questions: (1) How are chaperone levels co-ordinated with tissue-specific demands on protein folding? (2) How do different cell-types regulate chaperone genes when exposed to the same misfolding stress?
Cellular chaperone levels and their response to misfolding stress are both driven by transcriptional changes and influenced by chromatin. The proposed work will bring the conceptual, technological and computational advances of chromatin/ transcription field to understand chaperone biology and misfolding diseases. Using in vivo mouse model and in vitro differentiation model, we will investigate molecular mechanisms that control chaperone levels in relevant tissues. Our work will provide insights into functional specialization of chaperones driven by tissue-specific folding demands. We will develop a novel and ambitious approach to assess protein-folding capacity in single cells moving the chaperone field beyond state-of-the-art. Thus by implementing genetic, computational and biochemical approaches, we aim to understand cell-type-specificity of chaperone regulation.
Summary
Protein misfolding causes devastating health conditions such as neurodegeneration. Although the disease-causing protein is widely expressed, its misfolding occurs only in certain cell-types such as neurons. What governs the susceptibility of some tissues to misfolding is a fundamental question with biomedical relevance.
Molecular chaperones help cellular proteins fold into their native conformation. Despite the generality of their function, chaperones are differentially expressed across various tissues. Moreover exposure to misfolding stress changes chaperone expression in a cell-type-dependent manner. Thus cell-type-specific regulation of chaperones is a major determinant of susceptibility to misfolding. The molecular mechanisms governing chaperone levels in different cell-types are not understood, forming the basis of this proposal. We will take a multidisciplinary approach to address two key questions: (1) How are chaperone levels co-ordinated with tissue-specific demands on protein folding? (2) How do different cell-types regulate chaperone genes when exposed to the same misfolding stress?
Cellular chaperone levels and their response to misfolding stress are both driven by transcriptional changes and influenced by chromatin. The proposed work will bring the conceptual, technological and computational advances of chromatin/ transcription field to understand chaperone biology and misfolding diseases. Using in vivo mouse model and in vitro differentiation model, we will investigate molecular mechanisms that control chaperone levels in relevant tissues. Our work will provide insights into functional specialization of chaperones driven by tissue-specific folding demands. We will develop a novel and ambitious approach to assess protein-folding capacity in single cells moving the chaperone field beyond state-of-the-art. Thus by implementing genetic, computational and biochemical approaches, we aim to understand cell-type-specificity of chaperone regulation.
Max ERC Funding
1 992 500 €
Duration
Start date: 2020-01-01, End date: 2024-12-31
Project acronym ChromoSOMe
Project Canonical and Non-canonical modes of Chromosome Segregation in Oocyte Meiosis
Researcher (PI) Julien Dumont
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Call Details Consolidator Grant (CoG), LS3, ERC-2018-COG
Summary Cell division is crucial for the development of complex organisms, for the homeostasis of tissues, and for the reproductive capacity of individuals. While most somatic cells are diploid and proliferate through mitosis, multiplication of sexually reproducing species relies on haploid gametes that are generated through a specialized cell division process called meiosis. To achieve this reduction in ploidy, two rounds of chromosome segregation follow a single phase of genome replication. Inaccuracy in this process leads to gametes that carry an incorrect number of chromosomes and to aneuploid embryos after fertilization. In their vast majority, these are non-viable and lead to spontaneous abortion: defective meiotic division is therefore a major obstacle in achieving reproduction. However, the key principles that drive this process are still poorly understood, one main reason being the diversity of the molecular scenarios that have been adopted across evolution to regulate oocyte chromosome segregation.
To dissect the key components of oocyte meiotic chromosome segregation, we propose to carry out a multi-disciplinary approach, combining several nematode species with the use of high-resolution live and electron microscopy, cutting edge genomic and proteomic technologies, and biochemistry coupled to in silico modeling. In Work Package 1 (WP1), we will analyze the molecular mechanisms controlling the self-assembly of the chromosome segregation machinery -the meiotic spindle- in the oocyte. WP2 will focus on defining how chromosome segregation is achieved in oocytes with non-canonical kinetochore geometry. WP3 aims at analyzing meiotic divisions in parthenogenetic nematodes with specific meiotic constraints, such as centrosomal oogenesis and unichromosomal genomes. By considering the wealth of mechanisms that can drive chromosome segregation in oocytes, this project will provide decisive steps towards understanding the essential and universal features of female meiosis.
Summary
Cell division is crucial for the development of complex organisms, for the homeostasis of tissues, and for the reproductive capacity of individuals. While most somatic cells are diploid and proliferate through mitosis, multiplication of sexually reproducing species relies on haploid gametes that are generated through a specialized cell division process called meiosis. To achieve this reduction in ploidy, two rounds of chromosome segregation follow a single phase of genome replication. Inaccuracy in this process leads to gametes that carry an incorrect number of chromosomes and to aneuploid embryos after fertilization. In their vast majority, these are non-viable and lead to spontaneous abortion: defective meiotic division is therefore a major obstacle in achieving reproduction. However, the key principles that drive this process are still poorly understood, one main reason being the diversity of the molecular scenarios that have been adopted across evolution to regulate oocyte chromosome segregation.
To dissect the key components of oocyte meiotic chromosome segregation, we propose to carry out a multi-disciplinary approach, combining several nematode species with the use of high-resolution live and electron microscopy, cutting edge genomic and proteomic technologies, and biochemistry coupled to in silico modeling. In Work Package 1 (WP1), we will analyze the molecular mechanisms controlling the self-assembly of the chromosome segregation machinery -the meiotic spindle- in the oocyte. WP2 will focus on defining how chromosome segregation is achieved in oocytes with non-canonical kinetochore geometry. WP3 aims at analyzing meiotic divisions in parthenogenetic nematodes with specific meiotic constraints, such as centrosomal oogenesis and unichromosomal genomes. By considering the wealth of mechanisms that can drive chromosome segregation in oocytes, this project will provide decisive steps towards understanding the essential and universal features of female meiosis.
Max ERC Funding
1 561 563 €
Duration
Start date: 2020-01-01, End date: 2024-12-31
Project acronym CORKtheCAMBIA
Project Thickening of plant organs by nested stem cells
Researcher (PI) Ari Pekka MÄHÖNEN
Host Institution (HI) HELSINGIN YLIOPISTO
Call Details Consolidator Grant (CoG), LS3, ERC-2018-COG
Summary Growth originates from meristems, where stem cells are located. Lateral meristems, which provide thickness to tree stems and other plant organs, include vascular cambium (produces xylem [wood] and phloem); and cork cambium (forms cork, a tough protective layer).
We recently identified the molecular mechanism that specifies stem cells of vascular cambium. Unexpectedly, this same set of experiments revealed also novel aspects of the regulation of cork cambium, a meristem whose development has remained unknown. CORKtheCAMBIA aims to identify the stem cells of cork cambium and reveal how they mechanistically regulate plant organ thickening. Thus, stemming from these novel unpublished findings and my matching expertise on plant stem cells and lateral growth, the timing is perfect to discover the molecular mechanism underlying specification of stem cells of cork cambium.
To identify the origin of stem cells of cork cambium, 1st-we will combine lineage tracing with a detailed molecular marker analysis. To deduce the cell dynamics of cork cambium, 2nd-we will follow regeneration of the stem cells after ablation of this meristem. To discover the molecular factors regulating the stem cell specification of cork cambium, 3rd-we will utilize molecular genetics and a novel method (inducible CRISPR/Cas9 mutant targeting) being developed in my lab. Since the lateral growth is orchestrated by two adjacent, nested meristems, cork and vascular cambia, the growth process must be tightly co-regulated. Thus, 4th-an in silico model of the intertwined growth process will be generated. By combining modelling with experimentation, we will uncover mechanistically how cork and vascular cambium coordinate lateral growth.
CORKtheCAMBIA will thus provide long-awaited insight into the regulatory mechanisms specifying the stem cells of lateral meristem as whole, lay the foundation for studies on radial thickening and facilitate rational manipulation of lateral meristems of crop plants and trees.
Summary
Growth originates from meristems, where stem cells are located. Lateral meristems, which provide thickness to tree stems and other plant organs, include vascular cambium (produces xylem [wood] and phloem); and cork cambium (forms cork, a tough protective layer).
We recently identified the molecular mechanism that specifies stem cells of vascular cambium. Unexpectedly, this same set of experiments revealed also novel aspects of the regulation of cork cambium, a meristem whose development has remained unknown. CORKtheCAMBIA aims to identify the stem cells of cork cambium and reveal how they mechanistically regulate plant organ thickening. Thus, stemming from these novel unpublished findings and my matching expertise on plant stem cells and lateral growth, the timing is perfect to discover the molecular mechanism underlying specification of stem cells of cork cambium.
To identify the origin of stem cells of cork cambium, 1st-we will combine lineage tracing with a detailed molecular marker analysis. To deduce the cell dynamics of cork cambium, 2nd-we will follow regeneration of the stem cells after ablation of this meristem. To discover the molecular factors regulating the stem cell specification of cork cambium, 3rd-we will utilize molecular genetics and a novel method (inducible CRISPR/Cas9 mutant targeting) being developed in my lab. Since the lateral growth is orchestrated by two adjacent, nested meristems, cork and vascular cambia, the growth process must be tightly co-regulated. Thus, 4th-an in silico model of the intertwined growth process will be generated. By combining modelling with experimentation, we will uncover mechanistically how cork and vascular cambium coordinate lateral growth.
CORKtheCAMBIA will thus provide long-awaited insight into the regulatory mechanisms specifying the stem cells of lateral meristem as whole, lay the foundation for studies on radial thickening and facilitate rational manipulation of lateral meristems of crop plants and trees.
Max ERC Funding
1 999 752 €
Duration
Start date: 2019-09-01, End date: 2024-08-31
Project acronym DCRIDDLE
Project A novel physiological role for IRE1 and RIDD..., maintaining the balance between tolerance and immunity?
Researcher (PI) Sophie Janssens
Host Institution (HI) VIB VZW
Call Details Consolidator Grant (CoG), LS3, ERC-2018-COG
Summary Dendritic cells (DCs) play a crucial role as gatekeepers of the immune system, coordinating the balance between protective immunity and tolerance to self antigens. What determines the switch between immunogenic versus tolerogenic antigen presentation remains one of the most puzzling questions in immunology. My team recently discovered an unanticipated link between a conserved stress response in the endoplasmic reticulum (ER) and tolerogenic DC maturation, thereby setting the stage for new insights in this fundamental branch in immunology.
Specifically, we found that one of the branches of the unfolded protein response (UPR), the IRE1/XBP1 signaling axis, is constitutively active in murine dendritic cells (cDC1s), without any signs of an overt UPR gene signature. Based on preliminary data we hypothesize that IRE1 is activated by apoptotic cell uptake, orchestrating a metabolic response from the ER to ensure tolerogenic antigen presentation. This entirely novel physiological function for IRE1 entails a paradigm shift in the UPR field, as it reveals that IRE1’s functions might stretch far from its well-established function induced by chronic ER stress. The aim of my research program is to establish whether IRE1 in DCs is the hitherto illusive switch between tolerogenic and immunogenic maturation. To this end, we will dissect its function in vivo both in steady-state conditions and in conditions of danger (viral infection models). In line with our data, IRE1 has recently been identified as a candidate gene for autoimmune disease based on Genome Wide Association Studies (GWAS). Therefore, I envisage that my research program will not only have a large impact on the field of DC biology and apoptotic cell clearance, but will also yield new insights in diseases like autoimmunity, graft versus host disease or tumor immunology, all associated with disturbed balances between tolerogenic and immunogenic responses.
Summary
Dendritic cells (DCs) play a crucial role as gatekeepers of the immune system, coordinating the balance between protective immunity and tolerance to self antigens. What determines the switch between immunogenic versus tolerogenic antigen presentation remains one of the most puzzling questions in immunology. My team recently discovered an unanticipated link between a conserved stress response in the endoplasmic reticulum (ER) and tolerogenic DC maturation, thereby setting the stage for new insights in this fundamental branch in immunology.
Specifically, we found that one of the branches of the unfolded protein response (UPR), the IRE1/XBP1 signaling axis, is constitutively active in murine dendritic cells (cDC1s), without any signs of an overt UPR gene signature. Based on preliminary data we hypothesize that IRE1 is activated by apoptotic cell uptake, orchestrating a metabolic response from the ER to ensure tolerogenic antigen presentation. This entirely novel physiological function for IRE1 entails a paradigm shift in the UPR field, as it reveals that IRE1’s functions might stretch far from its well-established function induced by chronic ER stress. The aim of my research program is to establish whether IRE1 in DCs is the hitherto illusive switch between tolerogenic and immunogenic maturation. To this end, we will dissect its function in vivo both in steady-state conditions and in conditions of danger (viral infection models). In line with our data, IRE1 has recently been identified as a candidate gene for autoimmune disease based on Genome Wide Association Studies (GWAS). Therefore, I envisage that my research program will not only have a large impact on the field of DC biology and apoptotic cell clearance, but will also yield new insights in diseases like autoimmunity, graft versus host disease or tumor immunology, all associated with disturbed balances between tolerogenic and immunogenic responses.
Max ERC Funding
1 999 196 €
Duration
Start date: 2019-02-01, End date: 2024-01-31
Project acronym DiRECT
Project Directly reprogrammed renal cells for targeted medicine
Researcher (PI) Soeren LIENKAMP
Host Institution (HI) UNIVERSITAT ZURICH
Call Details Starting Grant (StG), LS3, ERC-2018-STG
Summary The global incidence of kidney disease is on the rise, but little progress has been made to develop novel therapies or preventative measures.
New methods to generated renal tissue in vitro hold great promise for regenerative medicine and the prospect of organ replacement. Most of the strategies employed differentiate induced pluripotent stem cells (iPSCs) into kidney organoids, which can be derived from patient tissue.
Direct reprogramming is an alternative approach to convert one cell type into another using cell fate specifying transcription factors. We were the first to develop a method to directly reprogram mouse and human fibroblasts to kidney cells (induced renal tubular epithelial cells - iRECs) without the need for pluripotent cells. Morphological, transcriptomic and functional analyses found that directly reprogrammed iRECs are remarkably similar to native renal tubular cells. Direct reprogramming is fast, technically simple and scalable.
This proposal aims to establish direct reprogramming in nephrology and develop novel in vitro models for kidney diseases that primarily affect the renal tubules. We will unravel the mechanics of how only four transcription factors can change the morphology and function of fibroblasts towards a renal tubule cell identity. These insights will be used to identify alternative routes to directly reprogram tubule cells with increased efficiency and accuracy. We will identify cell type specifying factors for reprogramming of tubular segment specific cell types. Finally, we will use of reprogrammed kidney cells to establish new in vitro models for autosomal dominant polycystic kidney disease and nephronophthisis.
Direct reprogramming holds enormous potential to deliver patient specific disease models for diagnostic and therapeutic applications in the age of personalized and targeted medicine.
Summary
The global incidence of kidney disease is on the rise, but little progress has been made to develop novel therapies or preventative measures.
New methods to generated renal tissue in vitro hold great promise for regenerative medicine and the prospect of organ replacement. Most of the strategies employed differentiate induced pluripotent stem cells (iPSCs) into kidney organoids, which can be derived from patient tissue.
Direct reprogramming is an alternative approach to convert one cell type into another using cell fate specifying transcription factors. We were the first to develop a method to directly reprogram mouse and human fibroblasts to kidney cells (induced renal tubular epithelial cells - iRECs) without the need for pluripotent cells. Morphological, transcriptomic and functional analyses found that directly reprogrammed iRECs are remarkably similar to native renal tubular cells. Direct reprogramming is fast, technically simple and scalable.
This proposal aims to establish direct reprogramming in nephrology and develop novel in vitro models for kidney diseases that primarily affect the renal tubules. We will unravel the mechanics of how only four transcription factors can change the morphology and function of fibroblasts towards a renal tubule cell identity. These insights will be used to identify alternative routes to directly reprogram tubule cells with increased efficiency and accuracy. We will identify cell type specifying factors for reprogramming of tubular segment specific cell types. Finally, we will use of reprogrammed kidney cells to establish new in vitro models for autosomal dominant polycystic kidney disease and nephronophthisis.
Direct reprogramming holds enormous potential to deliver patient specific disease models for diagnostic and therapeutic applications in the age of personalized and targeted medicine.
Max ERC Funding
1 499 917 €
Duration
Start date: 2019-03-01, End date: 2024-02-29
