Project acronym iMAC-FUN
Project Dissecting novel mechanisms of iron regulation during macrophage-fungal interplay
Researcher (PI) Georgios Chamilos
Host Institution (HI) IDRYMA TECHNOLOGIAS KAI EREVNAS
Country Greece
Call Details Consolidator Grant (CoG), LS6, ERC-2019-COG
Summary Airborne filamentous fungi (molds) are major causes of respiratory diseases in an expanding population of patients with complex immune and metabolic defects. Invasive mold infections (IMI) are associated with substantial mortality and enormous economic impact. Understanding pathogenesis of IMI is an unmet need for design of better therapies. We have put forward a novel mechanism for the pathogenesis of IMI, according to which development of IMI requires two discrete mechanisms (a) phagosome maturation arrest via inhibition of LC3-associated phagocytosis (LAP), which allows intracellular persistence of fungal conidia (spores), and (b) alteration in iron homeostasis, resulting in invasive fungal growth and lysis of the macrophage. On the pathogen site, fungal melanin targets LAP and affects macrophage metal homeostasis. On the macrophage site, iron distribution in subcellular compartments of all eukaryotic cells is controlled by ferric reductases and divalent cation transporters, in a process that remains molecularly unexplored. During mold infection a group of ferric reductases represent the most prominently transcriptionally modulated iron regulatory genes in macrophages. Thus, iron regulation is the critical determinant of macrophage-fungal interplay and is the focus of this project. We will use molds as model pathogens to (i) dissect the role of selected ferric reductases in infection, (ii) identify novel iron transporters implicated in host defense (iii) and explore mechanisms of melanin interference with iron regulation in macrophages. To this end, we will employ a robust, unbiased, approach combining transcriptomics, metalloproteomics, in vivo RNAi screening in Drosophila model of IMI, and validation studies in transgenic mice and eventually in human patients ex vivo. Dissecting the function of novel iron regulators in the macrophage will have profound impact on iron biology and is likely to have direct therapeutic implications for the management of IMI.
Summary
Airborne filamentous fungi (molds) are major causes of respiratory diseases in an expanding population of patients with complex immune and metabolic defects. Invasive mold infections (IMI) are associated with substantial mortality and enormous economic impact. Understanding pathogenesis of IMI is an unmet need for design of better therapies. We have put forward a novel mechanism for the pathogenesis of IMI, according to which development of IMI requires two discrete mechanisms (a) phagosome maturation arrest via inhibition of LC3-associated phagocytosis (LAP), which allows intracellular persistence of fungal conidia (spores), and (b) alteration in iron homeostasis, resulting in invasive fungal growth and lysis of the macrophage. On the pathogen site, fungal melanin targets LAP and affects macrophage metal homeostasis. On the macrophage site, iron distribution in subcellular compartments of all eukaryotic cells is controlled by ferric reductases and divalent cation transporters, in a process that remains molecularly unexplored. During mold infection a group of ferric reductases represent the most prominently transcriptionally modulated iron regulatory genes in macrophages. Thus, iron regulation is the critical determinant of macrophage-fungal interplay and is the focus of this project. We will use molds as model pathogens to (i) dissect the role of selected ferric reductases in infection, (ii) identify novel iron transporters implicated in host defense (iii) and explore mechanisms of melanin interference with iron regulation in macrophages. To this end, we will employ a robust, unbiased, approach combining transcriptomics, metalloproteomics, in vivo RNAi screening in Drosophila model of IMI, and validation studies in transgenic mice and eventually in human patients ex vivo. Dissecting the function of novel iron regulators in the macrophage will have profound impact on iron biology and is likely to have direct therapeutic implications for the management of IMI.
Max ERC Funding
2 000 000 €
Duration
Start date: 2020-09-01, End date: 2025-08-31
Project acronym NUCDDR
Project Nucleolar Responses to DNA Damage: rDNA, an emerging hub of genome instability
Researcher (PI) Eleftheria Dafni Pefani
Host Institution (HI) PANEPISTIMIO PATRON
Country Greece
Call Details Starting Grant (StG), LS1, ERC-2019-STG
Summary DNA lesions can impose serious threats to genome integrity and cell viability. Whereas DNA damage may occur anywhere in the genome, it is increasingly recognized that certain genomic loci rich in repetitive sequences display increased susceptibility to damage and are linked to chromosomal rearrangements and malignancy. Clusters of ribosomal DNA gene (rDNA) repeats, present on five different chromosomes, constitute the most heavily transcribed area of the human genome and are organized in a nuclear membrane-less organelle, the nucleolus. So far, putative links between rDNA damage and malignant processes have not been rigorously assessed.
We will address the hypothesis that rDNA repeats represent a major hub of genomic instability contributing to malignant transformation. Using state-of-the-art experimental systems that allow enrichment for nucleolar DNA damage, we will explore: (i) hypothesis-driven and mass spectrometry-based approaches to define regulators of the rDNA damage response; (ii) live imaging and advanced molecular biology tools to uncover how histone epigenetic changes and formation of RNA:DNA hybrids impact on nucleolar chromatin, nucleolar organization, rDNA transcription and repair ; (iii) cell models that recapitulate malignant transformation caused by inducible oncogene expression or epigenetic inactivation of tumour suppressors, to assess replication stress in rDNA repeats as a primary source of genomic instability and pertinent to hallmarks of cancer.
The proposed research is expected to yield novel insights into the signaling networks and biological processes regulating rDNA damage and repair within the nuclear environment and define how these mechanisms are corrupted during neoplastic transformation. This knowledge could be directly applicable to the design of new diagnostic or therapeutic strategies for cancer.
Summary
DNA lesions can impose serious threats to genome integrity and cell viability. Whereas DNA damage may occur anywhere in the genome, it is increasingly recognized that certain genomic loci rich in repetitive sequences display increased susceptibility to damage and are linked to chromosomal rearrangements and malignancy. Clusters of ribosomal DNA gene (rDNA) repeats, present on five different chromosomes, constitute the most heavily transcribed area of the human genome and are organized in a nuclear membrane-less organelle, the nucleolus. So far, putative links between rDNA damage and malignant processes have not been rigorously assessed.
We will address the hypothesis that rDNA repeats represent a major hub of genomic instability contributing to malignant transformation. Using state-of-the-art experimental systems that allow enrichment for nucleolar DNA damage, we will explore: (i) hypothesis-driven and mass spectrometry-based approaches to define regulators of the rDNA damage response; (ii) live imaging and advanced molecular biology tools to uncover how histone epigenetic changes and formation of RNA:DNA hybrids impact on nucleolar chromatin, nucleolar organization, rDNA transcription and repair ; (iii) cell models that recapitulate malignant transformation caused by inducible oncogene expression or epigenetic inactivation of tumour suppressors, to assess replication stress in rDNA repeats as a primary source of genomic instability and pertinent to hallmarks of cancer.
The proposed research is expected to yield novel insights into the signaling networks and biological processes regulating rDNA damage and repair within the nuclear environment and define how these mechanisms are corrupted during neoplastic transformation. This knowledge could be directly applicable to the design of new diagnostic or therapeutic strategies for cancer.
Max ERC Funding
1 499 525 €
Duration
Start date: 2020-06-01, End date: 2025-05-31
