Actin Polymerization Defects Induce Mitochondrial Dysfunction in Cellular Models of Nemaline Myopathies

Area of Science:

• * Cellular and Molecular Biology
• * Muscle Physiology
• * Rare Genetic Diseases

Background:

• * Nemaline myopathy (NM) is a common congenital myopathy characterized by
• nemaline bodies
• in muscle fibers.

Purpose of the Study:

• * Investigate pathophysiological alterations in NM using patient-derived dermal fibroblasts.
• * Identify potential therapeutic compounds targeting cellular defects in NM.

Main Methods:

• * Utilized dermal fibroblasts from patients with mutations in Actin Alpha 1 (ACTA1) and Nebulin (NEB) genes.
• * Analyzed actin filament polymerization via rhodamine-phalloidin staining and fluorescence microscopy.
• * Assessed mitochondrial function and bioenergetics.

Main Results:

• * Patient fibroblasts exhibited defective actin filament polymerization compared to controls.
• * Actin defects were linked to mitochondrial dysfunction.
• * Linoleic acid (LA) and L-carnitine (LCAR) improved actin polymerization and corrected mitochondrial bioenergetics in mutant fibroblasts.

Conclusions:

• * Cellular models derived from NM patients are valuable for studying disease mechanisms.
• * Targeting mitochondrial dysfunction with LA and LCAR shows promise for treating NM.
• * LA and LCAR can potentially reverse pathological alterations in NM cellular models.