Description du projet
Une thérapie génique pour les troubles cutanés héréditaires
Le terme «épidermolyse bulleuse» (EB) regroupe plusieurs troubles cutanés héréditaires rares, caractérisés par une peau fragile ayant tendance à la formation de bulles. L’EB est due à des mutations dans un éventail de gènes responsables de la cohésion intraépidermique, y compris les gènes codant la kératine, l’intégrine et la laminine. Les scientifiques du projet Holo-GT, financé par l’UE, ont déjà démontré l’efficacité d’une approche combinatoire et de thérapie génique pour le traitement de l’EB. Toutefois, en raison du profil héréditaire dominant de nombreuses maladies de la peau, l’addition de gènes ne convient pas à cette approche. Le consortium Holo-GT entend développer une stratégie de modification génétique et une approche pour renouveler les cellules souches cutanées qui font souvent défaut chez les patients atteints d’EB.
Objectif
Holo-GT will define innovative ex vivo gene therapy of dominant genetic skin disease, by using Epidermolysis Bullosa (EB) as a model system. EB is a group of dominantly or recessively inherited, devastating, incurable diseases marked by structural fragility of the integuments. The applicant has shown that combined ex vivo cell and gene therapy can cure the skin of recessive LAMB3-Junctional EB. This lifesaving procedure unveiled that the human epidermis is sustained solely by long-lived stem cells, detected as holoclone-forming cells, which generate transient progenitors referred to as meroclones and paraclones.
However, over 50% of EB are dominantly inherited, making gene addition unsuitable. Gene editing does not efficiently correct epidermal stem cells, which define a small proportion of clonogenic keratinocytes and cannot be prospectively isolated.
Holo-GT aims at designing a safe and efficacious protocol for dominant forms of EB through:
• Molecular characterization of the keratinocyte clonal types and pathways sustaining holoclone-forming cells by single-cell RNA profiling.
• Generation of induced holoclone-forming cells (iHolo) by transient expression of specific sets of transcription factors (identified in aim 1) able to reprogram progenitors into holoclone-forming cells.
• Development of custom-engineered CRISPR/Cas nucleases, based on selection-based directed evolution or structure-guided mutagenesis, able to fully distinguish wild type and mutant alleles.
• Using this newly developed CRISPR/Cas system, gene editing of iHolo prepared from keratinocyte cultures initiated from patients with dominant forms of EB.
Holo-GT could tackle not only dominant EBs but also other dominant genetic diseases of the epidermis and other squamous epithelia, as well as recessive forms of EB, particularly those characterized by the well-known depletion of stem cells, which could be rescued by the reprogramming of transient progenitors into holoclone-forming cells (iHolo).
Champ scientifique
Mots‑clés
Programme(s)
Thème(s)
Régime de financement
ERC-ADG - Advanced GrantInstitution d’accueil
41121 Modena
Italie