Development of a gene therapy strategy for

Charcot-Marie-Tooth disease type 2A (CMT2A)

L’Associazione Progetto Mitofusina2 onlus onlus supports this project on the scientific responsibility of Prof. Stefania Corti, Prof. Giacomo Pietro Comi and Prof. Nereo Bresolin, researchers and neurologists of “Centro Dino Ferrari” at University of Milan.

This project involves a young researchers team (biology and biotechnology), coordinated by Doct. Federica Rizzo at University of Milan and at IRCCS Ca’ Granda Foundation, Ospedale Maggiore Policlinico, Milan.

We have been collaborating with Associazione Progetto Mitofusina2 onlus actively, bridging the gap between science and society in order to sensitize towards the existence of this rare disease, actually without a cure. We supported their activities and we plan to organize other events together, establishing a continuous and challenging dialog.

PATHOLOGY

Charcot-Marie-Tooth disease type 2A (CMT2A) is a polyneuropathy that affects motor and sensory neurons, resulting in progressive weakness, limb muscle atrophy and loss of sensitivity. The disease is caused by mutations in the Mitofusin2 (MFN2) gene, which encodes MFN2 mitochondrial protein, involved into mitochondria structure and function regulation. Up to now, there is no cure for this disorder.

The process to translate a potential therapy into the clinic is complex and requires time. Moreover, it is not as a straight way, but a circular one: the collaboration among patients, doctors and researchers is really essential.

WHAT WE HAVE DONE

The data obtained from the study, carried out by our laboratory (Neuronal Stem Cells Lab), has been recently published on Human Molecular Genetics.

The reprogramming of mature cells in induced pluripotent stem cells (iPSCs) offers the possibility of obtaining patient-specific cells, such as human motor neurons, typically affected in the disease, but impossible to obtain directly from patients with other strategies. In this way, we have generated an in vitro disease model, currently not available yet. Indeed, we generated different iPSC lines from CMT2A patients and we demonstrated their differentiation in motor neurons, one of the affected cellular types in the disease. These cells exhibited a global reduction in mitochondrial content and altered mitochondrial positioning without significant differences in survival and axon elongation.

This study contributed to deepen the knowledge about disease molecular mechanisms, generating an in vitro model of CMT2A based on patient-specific iPSCs, and to identify new possible molecular therapeutic targets for the disease.

WHAT WE PLAN TO DO

In addition to the study of the disease pathogenic mechanism, our project aims to develop a possible therapeutic approach for CMT2A, not currently available. Up to now, gene therapy represents a promising strategy to correct the genetic cause of the disease. Positive results with this strategy have been obtained in clinical trials for other neuromuscular disease such as Spinal Muscular Atrophy (SMA). Our goal is to apply the same approach to CMT2A.

However, CMT2A is characterized not only by the lack of the “healthy” gene, but also by the presence of the affected MFN2 protein. Hence, the reintroduction of the “healthy” gene is not sufficient, but it is also necessary to switch off the mutated gene.

In particular, we aim to evaluate the efficacy of this therapeutic strategy in the in vitro patient-specific model, generated in the already published paper, and in the in vivo model of the pathology. The project will be developed as follows:

Evaluation of the impact of the therapeutic strategy in the in vitro model of the disease

We will evaluate the efficacy of this therapeutic strategy in the patient-specific motor neurons, previously differentiated from iPSCs, studying any modification of the pathological phenotype after the treatment.

Evaluation of the impact of the therapeutic strategy in the in vivo model of the disease.

We will evaluate the efficacy of this therapeutic strategy in the murine model of CMT2A (MitoCharc1), considering any modification of the pathological phenotype after the treatment.

Preliminary data-our publications on international peer reviewed journal about CMT2A disease