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Oxidative stress and calcium homeostasis in dystrophic skin fibroblasts
D Degl'Innocenti1, A Pieri, F Rosati
1Department of Biochemical Sciences, University of Florence, Firenze, Italy.
Abstract:
Muscular dystrophy is a genetic disease that affects primarily skeletal muscle. The dystrophin absence has been related to the degeneration of muscle fibres. Indirect evidences suggest that oxidative stress may play a role in the pathogenesis of the disease, but the significance and precise extent of this contribution is poorly understood. In this paper we show that Becker Muscular Dystrophy (BMD) and Duchenne Muscular Dystrophy (DMD) skin fibroblasts are more susceptible to H2O2 treatment than are fibroblasts from unaffected persons. In particular, we found that, in growing DMD skin fibroblasts, the oxidative treatment resulted in significantly reduced growing capacity. We also investigated the concentrations of intracellular calcium during H2O2 treatment. The intracellular free calcium concentration increased by 22%, 35%, and 40% in unaffected, BMD, and DMD fibroblasts, respectively. However, the increase of the intracellular free calcium concentration is not related, as previously hypothesized, to a reduction of acylphosphatase concentrations, which seem to be unaffected by the H2O2 treatment, but rather to reduced enzyme activity.
Insights
Skin cells from muscular dystrophy patients show increased susceptibility to oxidative stress. Hydrogen peroxide treatment reduced growth in Duchenne muscular dystrophy cells and altered calcium levels in both Becker and Duchenne muscular dystrophy cells.
Area of Science:
- Biochemistry
- Genetics
- Cell Biology
Background:
- Muscular dystrophy is a genetic disorder impacting skeletal muscle, with dystrophin absence linked to muscle fiber degeneration.
- Oxidative stress is implicated in muscular dystrophy pathogenesis, but its exact role remains unclear.
Purpose of the Study:
- To investigate the susceptibility of skin fibroblasts from patients with Becker Muscular Dystrophy (BMD) and Duchenne Muscular Dystrophy (DMD) to oxidative stress.
- To explore the role of oxidative stress in cellular dysfunction in muscular dystrophy.
Main Methods:
- Exposing skin fibroblasts from unaffected individuals, BMD, and DMD patients to hydrogen peroxide (H2O2).
- Assessing cell growth capacity and intracellular free calcium concentrations.
- Measuring acylphosphatase concentrations and enzyme activity.
Main Results:
- BMD and DMD fibroblasts exhibited higher susceptibility to H2O2 compared to unaffected fibroblasts.
- Oxidative treatment significantly reduced the growth capacity of DMD fibroblasts.
- Intracellular free calcium concentration increased in BMD (35%) and DMD (40%) fibroblasts, but not due to reduced acylphosphatase concentration, rather due to decreased enzyme activity.
Conclusions:
- Skin fibroblasts from muscular dystrophy patients are more vulnerable to oxidative stress.
- Oxidative stress impacts cell growth and calcium homeostasis in muscular dystrophy.
- The observed calcium increase is linked to reduced enzyme activity, not acylphosphatase levels.