Laboratoire de Physiomedecine moléculaire (LP2M) - CNRS-UMR 7370, Université de Nice-Sophia antipolis, Faculté de Médecine, 28 Av Valombrose, Tour Pasteur06108 Nice, France.
We are looking for excellent applicants for a PhD position for three years, starting between September and December 2015. The fellowship is granted by the ICST Labex andbe awarded for one of the 3 thesis topics described below. Applicants must imperatively choose one of the three topics. They have to send a detailed CV (with ranks and marks for the Master's degree or equivalent) to before July 15 at 12pm, accompanied by a letter explaining their motivation for a PhD and for the chosen subject. Following a pre-selection based on the sent documents, an external panel of scientists will conduct an audition of the selected candidates. The date of the audition will be between July 20 and 29th in NICE at the laboratory.
PROJECT 1
Name of the thesis director (with HDR) :Saïd BENDAHHOU.
Title: Role of the Kir2.1 potassium channels in excitable and non-excitable tissues.
PROJECT 2
Name of the thesis director (with HDR) : Laurent COUNILLON.
Title: The Na+/H+ exchangers expressed in the intracellular compartments. From their biochemical function to their implication in Autism spectrum disorders.
PROJECT 3
Name of the thesis director (with HDR) : Christophe DURANTON/ Isabelle RUBERA.
Title: Roles and functions of the newly identified Cl- channels LRRC8 familyin kidney physiology and differentiation of immune cells.
PROJECT 1
PhD Student Request Form
Host team:
Name of the thesis director (with HDR) :…………………..Saïd BENDAHHOU
Starting date : September 1st 2015
Thesis project
Role of the Kir2.1 potassium channels in excitable and non-excitable tissues.
Andersen’s syndrome (AS) is complex disorder unique with patient phenotypes mixing periodic paralyses, cardiac arrhythmia, bone malformation, and cognitive abnormalities. We have made progress understanding how mutations in the KCNJ2, the only gene associated with AS, can lead to electrical dysfunctions in both skeletal and cardiac muscles. The involvement of Kir2.1 channels in AS has emphasized the physiological importance of sarcolemmal inward rectifiers in regulating cellular excitability. However, our understanding of the fundamental molecular and biophysical mechanisms responsible for Kir2.1 dysfunction and an explanation for dominant negative mutant channel behavior in this disorder are incomplete. Moreover, the contribution of Kir2.1 to muscle excitability and bone development remains to be elucidated. The actual project will focus on determining the role of the Kir2.1 channel in excitability and bone morphogenesis in vitro and in vivo, using biopsies from AS patients and animal models. We have used AS muscle biopsies to understand the role of the potassium channels in both skeletal muscle excitability and bone morphogenesis. If muscle biopsies may be appropriate in addressing skeletal muscle issues, this may have some limitations in other tissues. Reprogramming of human somatic cells into induced pluripotent stem cells (iPSCs) and differentiating them into the 3 germ layers is a new powerful technology that offer an attractive tool to model human developmental pathways1. Furthermore, disease-specific iPSCs allow an unprecedented experimental plateform for basic research as well as highthroughput screening 2. This may be particularly relevant for developmental disorders in which the effects on cells during the early life are not accessible. We will take advantage of the availability of three AS muscle biopsies (along with biopsies from controls) to generate human AS-specific iPSCs. These human AS-specific iPSCs will be differentiated in vitro into skeletal muscle, cardiac muscle, or osteoblasts according to known protocols and mimickingthe corresponding developmental pathways.First, a thorough functional characterization will be carried out on the undifferentiated as well as differentiated cells using conventional patch clamp techniques. A combination of transcriptomics and proteomic analyses, immunohistochemistry, microscopy imaging, and 2-photon Ca2+ imaging will be used to determine the role of the Kir2.1 potassium channel in cell excitability as well as during the different key steps of bone morphogenesis. In parallel, mouse embryos will be injected with either WT or AS mutant constructs to generate mouse model allowing the identification of the critical steps involving Kir2.1 channel during embryonic stages and especially during palate formation. In mouse development, the prospective palatal mesenchymal cells begin to be specified in the maxillary processes at embryonic day 11.5 (E11.5) 3. The developing palate shelves first grow down vertically along the two sides of the tongue between E12.5 and E13.5. From E14.5, however, the two palatal shelves elevate above the level of the dorsal tongue. It has been recently shown that kcnj2 is expressed at lower levels during early developmental stages (at day E10.5) in fetal heart4. We will monitor the transcript and protein expression level in mouse tissues of the kcnj2 as well as that of osteogenic genes. Using a combination of immunohistochemistry, microarray, and biochemical techniques, we will identify the molecular determinants that have been affected by the lack of the Ik1 current expression, and may likely be involved in kir2.1 signaling during osteogenesis. This combination of both in vitro (human cells) and in vivo (on mouse) studies will allow to obtain converging data on the role of Kir2.1 in muscle excitability and during mammalian development. This project fits well in the TASK 2 of the Labex scientific themes (molecular and cellular physiology of ion channels). The scheduled experiments will involve the inward rectifier Kir2.1 potassium channels in human ex vivo models that are carried out within many teams of the Labex. Making human induced pluripotent stem cells (iPSCs) from diseased tissues, which is part of the thesis project, may turn out to be very useful for other Labex teams. The generation of a conditional kcnj2 knockout mouse (funding requested to Fondation Maladies rares) may be beneficial also to other teams of the ICST labex.
1 Takahashi K, et al. (2007) Cell 131: 861-‐72.
2 Park IH, et al. (2008) Cell 134: 877-‐86.
3 Murray JC, and Schutte BC (2004) J Clin Invest 113: 1676--‐8.
4 Liu A, et al. (2010) CellPhysiolBiochem 26: 413--‐20.
CNRS-UMR 7370 -Laboratoire de Physiomedecine moléculaire, Université de Nice-Sophia antipolis Faculté de Médecine, 28 Av Valombrose, Tour Pasteur
06108 Nice, France. e-mail:
PROJECT 2
PhD Student Request Form
Host team:
Name of the thesis director (with HDR) :…………………..Laurent COUNILLON
Starting date : September 1st 2015
Thesis project
The Na+/H+ exchangers expressed in the intracellular compartments. From their biochemical function to their implication in Autism spectrum disorders.
Na+/H+ Exchangers (NHEs) are expressed in all biological systems. In vertebrates, three isoforms of NHEs are mostly restricted to intracellular compartments. Their sequences are highly conserved and their mRNAs are detected in a number of organs in mammals, including the central nervous system. In 2006, a deletion of the gene encoding NHE-7 was found in mental retardation patients (5-6) and in 2008 two studies have linked defects NHE-6 and NHE-9 to genetic syndromes associating cognitive disorders autism or attention deficit type, epilepsy and cerebellar degeneration (7). Despite this importance, little is known about the role of these intracellular exchangers in the regulation of the pH of intracellular compartments. Indeed, the study of their biochemical and pharmacological characteristics, essential to understanding their function, has encountered the fact that they are sequestered within the cells and are very poorly accessible for measurements. We managed to solve this problem by selecting cell lines capable of withstanding acute cytosolic acidification, through expression NHE-6 or 7 at the plasma membrane. We now use an arsenal of ion transport measurement techniques developed in our team (8-9) to study the kinetics, ion selectivity, pharmacology and regulation of these carriers in a quasi-exhaustive manner. In parallel we are studying their localization in organs and particularly in the brain. We work with clinical groups whose goal is to identify mutations in patients with mental disorders like autism, mental retardation, or attention deficit. The PhD student will use the tools available in our laboratory (somatic genetics, fast kinetics, video microscopy and imaging etc) to study the NHE6 and NHE9 exchangers for all that concerns their ion selectivity, regulation, pharmacological profile, interactome and their cerebral and intracellular localization. The gained information will be used to measure their impact on vesicular pH, on trafficking and ultimately to understand their brain functionand role in neurodevelopment. The PhD student will also be involved in the genotyping of cohorts of patients and study of the impact of the mutations that will be eventually be found. This will bring together their function and patient phenotypes.
CNRS-UMR 7370 -Laboratoire de Physiomedecine moléculaire, Université de Nice-Sophia antipolis Faculté de Médecine, 28 Av Valombrose, Tour Pasteur
06108 Nice, France. e-mail:
PROJECT 3
PhD Student Request Form
Host team:
Name of the thesis director (with HDR) :Christophe DURANTON/ Isabelle RUBERA
Starting date : September 1st 2015
Thesis project
Roles and functions of the newly-identified channels family LRRC8 in kidney physiology and differentiation of immune cells.
A Chloride permeability sensitive to volume variation has been described in most of the eukaryote cells. This ubiquitous Cl- conductance plays a major role in regulatory volume decrease (RVD) 1 and apoptotic volume decrease (AVD) processes 2. Since more than 30 years the molecular identity of this conductance has remained elusive. In 2014, 2 independent studies 3, 4 have demonstrated the involvement of a new family of membrane proteins (LRRC8A/swell) in the generation of a volume sensitive Cl- conductance opening new perspectives of research in this field.
The aim of this original project is to establish the roles and the functions of this new family of channels in 1/ cell division, 2/ in apoptotic progression and 3/ in different cellular processes (epithelial mesenchymal transition and the behavior of immune cells). Extensively, animal model will be developed to study the importance of the LRCC8 family in kidney physiology and/or differentiation of immune cells. This project will focus on this new family of proteins to identified new processes and innovative targets to prevent kidney fibrosis and renalfailure5.
We are looking for strongly motivated candidates with interest in cell volume regulation and ions transport. The candidate will be formed to various techniques including electrophysiology (patch-clamp), fluorescence video-microscopy and/or flow cytometry analysis. Basic techniques of biochemistry and cell biology will be also developed during the PhD.
1. Barriere, H. et al. Am J PhysiolRenalPhysiol 284, F796-811 (2003).
2. L'Hoste, S. et al. Free RadicBiol Med 46, 1017-31 (2009).
3. Voss, F. K. et al. Science 344, 634-8 (2014).
4. Qiu, Z. et al. Cell 157, 447-58 (2014).
5. Liu, Y. J Am SocNephrol 15, 1-12 (2004).
CNRS-UMR 7370 -Laboratoire de Physiomedecine moléculaire, Université de Nice-Sophia antipolis Faculté de Médecine, 28 Av Valombrose, Tour Pasteur
06108 Nice, France. e-mail: or