Genome Editing and Muscle Stem Cells as a Therapeutic Tool for Muscular Dystrophies

Abstract

Purpose of review: Muscular dystrophies are a group of severe degenerative disorders characterized by muscle fiber degeneration and death. Therapies designed to restore muscle homeostasis and to replace dying fibers are being experimented, but none of those in clinical trials are suitable to permanently address individual gene mutation. The purpose of this review is to discuss genome editing tools such as CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated), which enable direct sequence alteration and could potentially be adopted to correct the genetic defect leading to muscle impairment.

Recent findings: Recent findings show that advances in gene therapy, when combined with traditional viral vector-based approaches, are bringing the field of regenerative medicine closer to precision-based medicine.

Summary: The use of such programmable nucleases is proving beneficial for the creation of more accurate in vitro and in vivo disease models. Several gene and cell-therapy studies have been performed on satellite cells, the primary skeletal muscle stem cells involved in muscle regeneration. However, these have mainly been based on artificial replacement or augmentation of the missing protein. Satellite cells are a particularly appealing target to address these innovative technologies for the treatment of muscular dystrophies.

Keywords: CRISPR/Cas; Gene therapy; Genome editing; Muscular dystrophies; Precision medicine; Stem cells.

Fig. 1

a Satellite cells originate from dorsal somites and are characterized by the expression of intracellular and extracellular markers: Pax7, CXCR4, Syndecan 3- and -4, c-Met, VCAM1, NCAM1, Caveolin-1, CD34, Calcitonin receptor, M-Cadherin. Integrin-α7 (ITGA7) and integrin-β1 (ITGB1). Satellite cells generate both cells aimed to replenish the satellite cell pool and cells that develop into myoblasts, precursors of the muscle fiber. Satellite cells reside at the periphery of the muscle fiber. b Diagram of regenerative medicine: satellite cells isolated from patient muscle and satellite-cells derived myoblasts can be treated with engineered nucleases (TALEN/CRISPR) to introduce a double strand break in their genome sequence, thus eliminating the mutation. NHEJ or HDR re-join the cleaved DS break, restoring the sequence. Corrected cells are then transplanted back into patient’s muscle