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Proposition de sujet de thèse à l’appui d’une demande de contrat doctoral 2017-2018
Renseignements relatifs à l’Unité de Recherche :
Label et intitulé : Inserm U1163/Institut Imagine
Nom et prénom du Directeur : Pr Stanislas Lyonnet
Téléphone : 01 42 75 49 96
Télécopie : 01 42 75 42 25
courriel : [email protected]
Renseignements relatifs à l’Equipe :
Nom de l’Equipe d’Accueil : Laboratoire des Maladies Rénales Héréditaires-1
Nom et prénom du responsable : Pr Antignac Corinne
Qualité du responsable : PU-PH
Téléphone : 01 42 75 43 45
Télécopie : 01 42 75 42 25
courriel : [email protected]
Renseignements relatifs au sujet de thèse :
Nom et prénom du Directeur de thèse (HDR) : Géraldine Mollet
Qualité : CR1
Téléphone :01 42 75 43 46
Télécopie : 01 42 75 42 25
courriel : [email protected]
Titre du sujet proposé :
(en français) : Caractérisation fonctionnelle du complexe KEOPS et son implication dans le syndrome
de Galloway-Mowat
(en anglais): Functional characterization of the KEOPS complex and its involvement in
Galloway-Mowat syndrome
Département (cocher le département correspondant au sujet de thèse qui n’est pas obligatoirement le
vôtre) :
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
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Biologie Cellulaire et moléculaire, Physiologie et Physiopathologie
Immunologie
Développement Génétique Neurobiologie et Vieillissement
Infectiologie, Microbiologie
Summary (5 lignes maximum) :
Hereditary podocytopathies represent a group of rare renal disorders characterized by massive urinary protein loss
due to a defect in the podocyte, a highly specialized cell of the plasma filtration barrier in the kidney. The purpose
of this project is to understand the role of the human KEOPS complex and its subunits in the pathophysiology of
the Galloway-Mowat syndrome and to characterize the role of the newly discovered C14 subunit within this
complex.
Proposition de sujet de thèse à l’appui d’une demande de contrat doctoral 2016-2017
Nom, prénom du directeur de l'unité de recherche : Pr Stanislas Lyonnet
Numéro de l'unité de recherche (et établissement de rattachement) : Inserm U1163
Nom, prénom du responsable de l'équipe d'accueil (EAD) : ANTIGNAC Corinne
Nom, prénom du directeur de thèse : MOLLET Géraldine
Titre du sujet de thèse proposé: Functional characterization of the KEOPS complex and its involvement
in Galloway-Mowat syndrome
Citer 5 mots clés : Nephrotic syndrome, podocyte, functional studies, animal and cellular models
Candidat pressenti :
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OUI
 NON
Contenu scientifique du programme de la thèse (en anglais)
Our group is interested in the identification and characterization of novel genes involved in
hereditary podocytopathies using the latest cutting-edge technologies, such as CRISPR/Cas9
technology, induced pluripotent stem cells (iPSCs) and animal models (mouse, Drosophila).
Hereditary podocytopathies is a group of rare renal disorders characterized by chronic
proteinuria and/or steroid-resistant nephrotic syndrome (SRNS) due to intrinsic alterations of the kidney
glomerular filtration barrier. The renal disease can be isolated or associated with several extra-renal
disorders, the most frequent being neurological disorders. Genetic studies identified more than 30 genes
responsible for monogenic forms, including five in our laboratory, all encoding proteins expressed in the
podocyte, a highly specialized epithelial cell that wraps around the capillaries of the renal glomerulus
making it a major component of the glomerular filtration barrier. Most of these genes encode structural
proteins and actin network regulators, but recently, our group highlighted the emergent role of proteins
involved in microtubule dynamic and organization in podocytes pathophysiology. The discovery of
mutations in genes affecting only the kidney and the nervous system has highlighted common molecular
processes essential to the development and maintenance of the renal glomerulus and the nervous system.
However, our understanding of the molecular and cellular processes leading to these neuro-renal
disorders is incomplete. The identification of mutations in KEOPS genes opens new avenues to
elucidate these pathophysiological mechanisms.
The aim of our project is to decipher the role of the new set of genes, encoding the KEOPS
complex, which we recently identified as being responsible for Galloway-Mowat syndrome (GAMOS),
a SRNS associated with microcephaly and developmental delay. These genes encode the four subunits
of an ubiquitous and essential multi-protein complex named KEOPS that catalyzes a unique
modification on tRNA (named t6A), that is necessary for translation initiation and translational
efficiency. Human KEOPS comprises at least 4 subunits: LAGE3, OSGEP, TP53RK, and TPRKB,
whereas a fifth subunit (Gon7) is present in yeast. OSGEP, present in all sequenced genomes, contains
the t6A activity but the role of the other subunits is not well understood. We also identified a novel gene
encoding C14 that we demonstrated to be the fifth subunit of the human KEOPS complex. Our
preliminary data made us hypothesized that C14 could stabilize the KEOPS complex.
This will be achieved by using podocyte cellular models, generated using the CRISPR/Cas9
genome editing to obtain either knock-out or knock-in of the genes, to study various cellular processes
(motility, proliferation and apoptosis using the real-time live-cell imaging IncuCyte technology and
EXCELLigence, and microtubule and/or actin network remodeling by immunofluorescence). To test our
hypothesis of C14 being a stabilizer, we will study the expression level and the half-life of KEOPS
subunits (using cycloheximide chase assay) in presence or absence of C14 in the different podocyte cell
lines generated above as well as in patient fibroblasts and LCLs. To model the disease in vivo, knock-in
mouse models will be generated by CRISPR/Cas9. These models will allow us to study the impact of
mutations on structure, development and function of brain and kidney, as well as cellular processes in
neurons (proliferation, apoptosis, differentiation, migration, arborization) at embryonic and adult stages.
Altogether, we hope to identify the pathological molecular mechanisms leading to GMS as well
as new molecular pathways that contribute to the pathology of podocytopathies.
Indiquez les trois meilleures publications récentes sur le sujet :1.Colin E et al.. Loss-of-function mutations in WDR73 are responsible for
microcephaly and steroid-resistant nephrotic syndrome: Galloway-Mowat syndrome. Am J Hum Genet. 2014 4;95(6):637-48.2-Huynh Cong E et al. A
homozygous missense mutation in the ciliary gene TTC21B causes familial FSGS. J Am Soc Nephrol. 2014; 25(11):2435-43.
3. Tory K, et al. Mutation-dependent recessive inheritance of NPHS2-associated steroid-resistant nephrotic syndrome. Nat Genet. 2014, 46(3):299-304.