Team 2

Targeted therapies for peripheral neuropathies

PI : Liliane Massade

Our research is focused on the use of nanomedecine based on small interfering RNA (siRNA) nanoparticles for the treatment of monogenic peripheral neuropathies. The strength of our team relies on complementary expertises in: 1) siRNA design, their characterization and optimization; 2) nanotechnologies, with the development of nanoparticle carriers for the delivery of siRNA and neuroactive molecules.

Recently, we investigated the regulation of a gene playing a key role in inherited demyelinating peripheral neuropathy by siRNA-squalene nanoparticles. The effect of these nanoparticles were tested in a mouse model, characterized by muscle weakness and atrophy and by slow nerve conduction velocity (European patent filed in September 2018). Importantly, we showed a normalization of the disease gene expression in this mouse model in addition of the reversal of the disease process and symptoms.

The figure below represents our projects for the next years. They consist of optimization of the treatment by siRNA-squalene nanoparticules and studying the mechanisms underlying the restoration of motor activity in the model of inherited demyelinating neuropathy. Our final aim is to reach clinical phases that will be done in the National reference center for Familial Amyloid Polyneuropathy and Other Rare Neuropathies, headed by Pr. David ADAMS.

This work is supported by a public grant overseen by the French National Research Agency (ANR) as part of the “Investissements d’Avenir” program (Labex NanoSaclay, reference: ANR-10-LABX-0035).

Nervous system development and myelination

PI : Marcel Tawk, Degerny Cindy

Our broad aim is to comprehend how the different cellular players within the nervous system interact to elaborate a functional neuronal entity. We mainly focus on the axo-glial communication, a fundamental process that orchestrates the assembly of the myelin sheath. The latter is a plasma membrane extension of specialised glial cells, Oligodendrocytes in the Central Nervous System and Schwann cells in the peripheral nervous system, that wraps around axons thereby permitting the rapid conduction of nerve impulses. Myelin disruption underlies several human diseases, such as Multiple sclerosis and Charcot-Marie-Tooth. In order to gain insight into this mechanism, we use the simplicity and high optical quality of the zebrafish embryo to monitor early and most fundamental behaviour of developing neuronal and glial cells. Some of the questions we beg: i) What are the molecular signallings that shape the peripheral myelinating glia? We have initiated a differential screen looking for genes that are dysregulated in the absence of Schwann cells using zebrafish. This screen helped us in identifying several new candidates that regulate different aspects of peripheral nervous system development. ii) How do Schwann cells migrate and divide along growing axons in order to myelinate? We use pharmacological and genetics tools, laser ablation, in vivo time-lapse imaging and transmitted electron microscopy to study the different molecular and cellular aspects that shape Schwann cell migration, division and behaviour.

Genetics and neurodevelopment

PI : Judith Melki

Our main research is focused on deciphering the genetic basis of several fetal and infantile diseases including arthrogryposis, a heterogeneous group of fetal neuromuscular disorders diseases, peripheral neuropathies and congenital anomaly of the cerebral vasculature. To support gene discovery, our have set up a genomics facility including a server for in-house bioinformatics analysis of SNPs and data from whole or targeted exome sequencing. Functional genomics are performed using various cellular or animal models to help understand how discovered gene mutations affect phenotypes.

This approach should lead to the identification of possibly novel signaling pathways involved in the process of development and/ maintenance of the neuromuscular system, peripheral myelination and brain vasculature in human. Moreover, our approaches should open new avenue in the genetic investigation of these diseases.

Promoting peripheral nerve regeneration by combining microsurgery

and neuroregenerative treatments

PI : Song Liu

A new surgical procedure for repairing the injured facial nerve with functional restoration has been developed using a rat model of facial nerve crush lesion. The method consists of hypoglossal–facial nerve ‘side’-to-side neurorrhaphy with a predegenerated nerve autograft for restoring functions after facial palsy. The method has then been successfully translated to the clinics and represents a major advance in the rehabilitation of facial nerve injury.

In preclinical studies, we test the usefulness of small molecules, in particular ligands of the tanslocator protein (TSPO), and of viral vectors delivering neurotrophic factors to promote the viability of sensory and motoneurons and the regeneration of axons after peripheral nerve injury.

Morphology and regeneration of the autonomic nervous system

PI : Thomas Bessede

Functional sequelae after abdomino-pelvic oncologic surgery are mainly related to nerve damage in the peripheral autonomic system. Because of anatomical, physiological and functional particularities, specific studies are required to try to improve its intraoperative nerve preservation and its postoperative nerve regeneration.

A Computer-Assisted Anatomical Dissection model was elaborated and is used to identify peripheral autonomic nerve fibers. Utilizing specific immunolabelings, we create 3D morphologic cartographies that are augmented with functional data. It is possible to analyse surgical dissection planes to better preserve vegetative functions.

As a second model, the recovery of erectile function was assessed after cavernous nerve injury in rats. Various techniques to promote cavernous neuroregeneration were assessed : pharmacologic treatments, support with silicone guide, autologous support, combined strategies.
Morphological and experimental data converge towards the objective of reducing functional sequelae after lesions of the autonomic nervous system. With new experimental and imaging models, it is possible to overpass surgical applications and collaborate in Neuroscience.

Preclinical development of analgesic

and anti-inflammatory molecules in pain models

PI : Dan Benhamou

The laboratory of anesthesia focus on preclinical development of analgesic and anti-inflammatory molecules such as Opiorphin (endogenous peptide inhibit NEP and APN) and Losmapimod (an inhibitor of p38 MAPK used as treatment of depression). We developed several murine models of neuropathic pain and showed that:
– Opiorphin as well as its stable derivate STR-324 have an analgesic effect and potentialize that of enkephalins.
– Losmapimod have analgesic and anti-inflammatory effects.

The future studies will consist to understand the mechanisms underlying these observations and to expend their studies on sever pains.

Dementias and neurodegeneration : A role for FKBP52 in Tau function

PI : Étienne-Émile Baulieu

We are studying in vivo functions of the FK506 Binding Protein 52 (FKBP52) in relation to nervous system development (axonal growth, neuron viability) and its interaction with the microtubule associated protein Tau.

The pathological mutant of Tau containing a proline-to-leucine mutation at position 301 (P301L) leads to severe human tauopathy. We identified a direct interaction of FKBP52 with Tau-P301L and its phosphorylated forms and demonstrated FKBP52’s ability to induce the formation of Tau-P301L oligomers. In a transgenic zebrafish expressing the human Tau-P301L mutant, FKBP52 knockdown is sufficient to redrive defective axonal outgrowth and branching related to Tau-P301L expression in spinal primary motoneurons.