Genes 2013, 4(2), 275-292; doi:10.3390/genes4020275
Article

Altered Ca2+ Homeostasis and Endoplasmic Reticulum Stress in Myotonic Dystrophy Type 1 Muscle Cells

1email, 2email, 3email, 2email, 4email, 2email, 4,5email and 2,* email
Received: 1 April 2013; in revised form: 3 May 2013 / Accepted: 16 May 2013 / Published: 4 June 2013
(This article belongs to the Special Issue Microsatellite Instability)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: The pathogenesis of Myotonic Dystrophy type 1 (DM1) is linked to unstable CTG repeats in the DMPK gene which induce the mis-splicing to fetal/neonatal isoforms of many transcripts, including those involved in cellular Ca2+ homeostasis. Here we monitored the splicing of three genes encoding for Ca2+ transporters and channels (RyR1, SERCA1 and CACN1S) during maturation of primary DM1 muscle cells in parallel with the functionality of the Excitation-Contraction (EC) coupling machinery. At 15 days of differentiation, fetal isoforms of SERCA1 and CACN1S mRNA were significantly higher in DM1 myotubes compared to controls. Parallel functional studies showed that the cytosolic Ca2+ response to depolarization in DM1 myotubes did not increase during the progression of differentiation, in contrast to control myotubes. While we observed no differences in the size of intracellular Ca2+ stores, DM1 myotubes showed significantly reduced RyR1 protein levels, uncoupling between the segregated ER/SR Ca2+ store and the voltage-induced Ca2+ release machinery, parallel with induction of endoplasmic reticulum (ER) stress markers. In conclusion, our data suggest that perturbed Ca2+ homeostasis, via activation of ER stress, contributes to muscle degeneration in DM1 muscle cells likely representing a premature senescence phenotype.
Keywords: myotonic dystrophy; muscle cells; Ca2+ homeostasis; SERCA; Ryr1; Cav1.1; ER stress
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MDPI and ACS Style

Botta, A.; Malena, A.; Loro, E.; Del Moro, G.; Suman, M.; Pantic, B.; Szabadkai, G.; Vergani, L. Altered Ca2+ Homeostasis and Endoplasmic Reticulum Stress in Myotonic Dystrophy Type 1 Muscle Cells. Genes 2013, 4, 275-292.

AMA Style

Botta A, Malena A, Loro E, Del Moro G, Suman M, Pantic B, Szabadkai G, Vergani L. Altered Ca2+ Homeostasis and Endoplasmic Reticulum Stress in Myotonic Dystrophy Type 1 Muscle Cells. Genes. 2013; 4(2):275-292.

Chicago/Turabian Style

Botta, Annalisa; Malena, Adriana; Loro, Emanuele; Del Moro, Giulia; Suman, Matteo; Pantic, Boris; Szabadkai, Gyorgy; Vergani, Lodovica. 2013. "Altered Ca2+ Homeostasis and Endoplasmic Reticulum Stress in Myotonic Dystrophy Type 1 Muscle Cells." Genes 4, no. 2: 275-292.

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