Loss of myogenic potential and fusion capacity of muscle stem cells isolated from contractured muscle in children with cerebral palsy

Abstract

Cerebral palsy (CP) is the most common cause of pediatric neurodevelopmental and physical disability in the United States. It is defined as a group of motor disorders caused by a nonprogressive perinatal insult to the brain. Although the brain lesion is nonprogressive, there is a progressive, lifelong impact on skeletal muscles, which are shorter, spastic, and may develop debilitating contractures. Satellite cells are resident muscle stem cells that are indispensable for postnatal growth and regeneration of skeletal muscles. Here we measured the myogenic potential of satellite cells isolated from contractured muscles in children with CP. When compared with typically developing (TD) children, satellite cell-derived myoblasts from CP differentiated more slowly (slope: 0.013 (SD 0.013) CP vs. 0.091 (SD 0.024) TD over 24 h, P < 0.001) and fused less (fusion index: 21.3 (SD 8.6) CP vs. 81.3 (SD 7.7) TD after 48 h, P < 0.001) after exposure to low-serum conditions that stimulated myotube formation. This impairment was associated with downregulation of several markers important for myoblast fusion and myotube formation, including DNA methylation-dependent inhibition of promyogenic integrin-β 1D (ITGB1D) protein expression levels (-50% at 42 h), and ~25% loss of integrin-mediated focal adhesion kinase phosphorylation. The cytidine analog 5-Azacytidine (5-AZA), a demethylating agent, restored ITGB1D levels and promoted myogenesis in CP cultures. Our data demonstrate that muscle contractures in CP are associated with loss of satellite cell myogenic potential that is dependent on DNA methylation patterns affecting expression of genetic programs associated with muscle stem cell differentiation and muscle fiber formation.

To switch from Botox to Dysport in children with CP, a real world, dose conversion, cost-effectiveness study

“…As satellite cells are important for skeletal muscle growth [89,90] but also play a role in the regulation of ECM production [93,94], these cells are of great interest for the study of contracture development in children with CP. Recently, Domenighetti and co-workers [214] showed a loss of myogenic potential for satellite cells isolated from CP muscle. The authors speculate that this was due to altered expression of genetic programs associated with muscle stem cell differentiation and muscle fiber formation, plausibly conditioned by an alternative DNA methylation pattern.…”

Muscle Microbiopsy to Delineate Stem Cell Involvement in Young Patients: A Novel Approach for Children With Cerebral Palsy

“…The timing of these interventions is not appropriate to associate muscle biopsies able to unravel the onset of muscle alterations in CP. Hence, the use of less invasive techniques to collect muscle biopsies earlier in the course of the disease is preferable and essential for optimizing treatment (Booth et al, 2001;Marbini et al, 2002;Domenighetti et al, 2018).…”

Joint and Muscle Assessments of the Separate Effects of Botulinum NeuroToxin-A and Lower-Leg Casting in Children With Cerebral Palsy

“…Recent literature indicates that hyperactive stretch reflexes, commonly labeled as spasticity, are considered to have less impact (2,3). Instead, alterations such as reduced muscle volume and atrophy, cellular and genetic factors have been related to the increased joint resistance (4)(5)(6). Despite the likelihood of multifactorial contributions, the most common non-surgical treatment for joint hyper-resistance is intramuscular injection of Botulinum NeuroToxin-A (BoNT-A) which, mainly targets hyperactive stretch reflexes by causing temporary muscle paralysis.…”