Core D will perform the qualitative and quantitative histological and ultrastructural checks that are necessary to support all other Projects. The Core will not only supply various techniques of electron, phase contrast and confocal microscopy, but it will also operate at a high standard of quality and offer an expert critical evaluation of the results of experimental and molecular alterations. The uniform and consistent use of high quality images will allow the detection of even subtle alterations in protein-protein interactions and in the response of individual cell organelles that either are at the basis of altered functions or are the long term results of such alterations. It is clear that the overall ultrastructural response of the muscle fiber to mutations affecting excitation-contraction coupling are quite specific and offer considerable insight into causative effects. In the past period we have evidenced a strong fiber type- and gender-dependence of the pathology, that correspindes quite well with similar variations in function. Two general approaches are proposed. One is to define any alterations in the relationships between the major protein components of calcium release units (CRUs, triads in skeletal muscle) within the context of the mutation and the other is to follow the development of pathology (most specifically mitochondrial, myofibrillar and CRUs'alterations) through development and aging and in relation to the known functional effects of the mutation on CRUs'channels.This will be achieved by combining light microscope techniques (phase contrast of fibers whole mounts and confocal imaging of fluorescently immunolabeled fibers) with thin sectioning and freeze-fracture for electron microscopy supplemented by quantitative morphometry techniques. The core aims at defining the primary impact of each mutation on the macromelcular assembly of calcium release units within a short term and the secondary impact on SR, mitochondria and contractile material on the long term.
To understand the muscle pathology of MH susceptible individuals it will be crucial to detect if any subtle alterations in the relationship between key component of the calcium release units machinery (mostly DHPR and RyR) underlie the RyR function imbalance. To that effect, ultrastructure will be tested by different technical approaches at an early and a late age.
|Franzini-Armstrong, Clara (2016) Can the Arrangement of RyR2 in Cardiac Muscle Be Predicted? Biophys J 110:2563-5|
|Polster, Alexander; Nelson, Benjamin R; Olson, Eric N et al. (2016) Stac3 has a direct role in skeletal muscle-type excitation-contraction coupling that is disrupted by a myopathy-causing mutation. Proc Natl Acad Sci U S A 113:10986-91|
|Bannister, Roger A; Sheridan, David C; Beam, Kurt G (2016) Distinct Components of Retrograde Ca(V)1.1-RyR1 Coupling Revealed by a Lethal Mutation in RyR1. Biophys J 110:912-21|
|Ronjat, Michel; Feng, Wei; Dardevet, Lucie et al. (2016) In cellulo phosphorylation induces pharmacological reprogramming of maurocalcin, a cell-penetrating venom peptide. Proc Natl Acad Sci U S A 113:E2460-8|
|Perni, Stefano; Dynes, Joseph L; Yeromin, Andriy V et al. (2015) Nanoscale patterning of STIM1 and Orai1 during store-operated Ca2+ entry. Proc Natl Acad Sci U S A 112:E5533-42|
|Franzini-Armstrong, Clara (2015) Electron Microscopy: From 2D to 3D Images with Special Reference to Muscle. Eur J Transl Myol 25:4836|
|Perni, Stefano; Marsden, Kurt C; Escobar, Matias et al. (2015) Structural and functional properties of ryanodine receptor type 3 in zebrafish tail muscle. J Gen Physiol 145:253|
|HenrÃquez-OlguÃn, Carlos; Altamirano, Francisco; Valladares, Denisse et al. (2015) Altered ROS production, NF-ÎºB activation and interleukin-6 gene expression induced by electrical stimulation in dystrophic mdx skeletal muscle cells. Biochim Biophys Acta 1852:1410-9|
|Fiszer, Dorota; Shaw, Marie-Anne; Fisher, Nickla A et al. (2015) Next-generation Sequencing of RYR1 and CACNA1S in Malignant Hyperthermia and Exertional Heat Illness. Anesthesiology 122:1033-46|
|Perni, Stefano; Marsden, Kurt C; Escobar, Matias et al. (2015) Structural and functional properties of ryanodine receptor type 3 in zebrafish tail muscle. J Gen Physiol 145:173-84|
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