| First Author | Tinklenberg JA | Year | 2023 |
| Journal | Am J Pathol | Volume | 193 |
| Issue | 10 | Pages | 1548-1567 |
| PubMed ID | 37419385 | Mgi Jnum | J:353839 |
| Mgi Id | MGI:7530476 | Doi | 10.1016/j.ajpath.2023.06.008 |
| Citation | Tinklenberg JA, et al. (2023) Different Mouse Models of Nemaline Myopathy Harboring Acta1 Mutations Display Differing Abnormalities Related to Mitochondrial Biology. Am J Pathol 193(10):1548-1567 |
| abstractText | ACTA1 encodes skeletal muscle-specific alpha-actin, which polymerizes to form the thin filament of the sarcomere. Mutations in ACTA1 are responsible for approximately 30% of nemaline myopathy (NM) cases. Previous studies of weakness in NM have focused on muscle structure and contractility, but genetic issues alone do not explain the phenotypic heterogeneity observed in patients with NM or NM mouse models. To identify additional biological processes related to NM phenotypic severity, proteomic analysis was performed using muscle protein isolates from wild-type mice in comparison to moderately affected knock-in (KI) Acta1(H40Y) and the minimally affected transgenic (Tg) ACTA1(D286G) NM mice. This analysis revealed abnormalities in mitochondrial function and stress-related pathways in both mouse models, supporting an in-depth assessment of mitochondrial biology. Interestingly, evaluating each model in comparison to its wild-type counterpart identified different degrees of mitochondrial abnormality that correlated well with the phenotypic severity of the mouse model. Muscle histology, mitochondrial respiration, electron transport chain function, and mitochondrial transmembrane potential were all normal or minimally affected in the TgACTA1(D286G) mouse model. In contrast, the more severely affected KI.Acta1(H40Y) mice displayed significant abnormalities in relation to muscle histology, mitochondrial respirometry, ATP, ADP, and phosphate content, and mitochondrial transmembrane potential. These findings suggest that abnormal energy metabolism is related to symptomatic severity in NM and may constitute a contributor to phenotypic variability and a novel treatment target. |
