Duchenne muscular dystrophy (DMD) is a severe and progressive muscle wasting disorder caused by mutations in the dystrophin gene that result in the absence of the membrane-stabilizing protein dystrophin. Dystrophin-deficient muscle fibres are fragile and susceptible to an influx of Ca²⁺, which activates inflammatory and muscle degenerative pathways. At present there is no cure for DMD, and existing therapies are ineffective. Here we show that increasing the expression of intramuscular heat shock protein 72 (Hsp72) preserves muscle strength and ameliorates the dystrophic pathology in two mouse models of muscular dystrophy. Treatment with BGP-15 (a pharmacological inducer of Hsp72 currently in clinical trials for diabetes) improved muscle architecture, strength and contractile function in severely affected diaphragm muscles in mdx dystrophic mice. In dko mice, a phenocopy of DMD that results in severe spinal curvature (kyphosis), muscle weakness and premature death, BGP-15 decreased kyphosis, improved the dystrophic pathophysiology in limb and diaphragm muscles and extended lifespan. We found that the sarcoplasmic/ endoplasmic reticulum Ca2²⁺-ATPase (SERCA, the main protein responsible for the removal of intracellular Ca²⁺) is dysfunctional in severely affected muscles of mdx and dko mice, and that Hsp72 interacts with SERCA to preserve its function under conditions of stress, ultimately contributing to the decreased muscle degeneration seen with Hsp72 upregulation. Treatment with BGP-15 similarly increased SERCA activity in dystrophic skeletal muscles. Our results provide evidence that increasing the expression of Hsp72 in muscle (through the administration of BGP-15) has significant therapeutic potential for DMD and related conditions, either as a self-contained therapy or as an adjuvant with other potential treatments, including gene, cell and pharmacological therapies.

Item Type:	Refereed Article
Keywords:	heat shock protein 72, sarcoplasmic reticulum calcium transporting adenosine triphosphatase, calcium, developmental biology, diabetes, drug, gene expression, ion, muscle, mutation, pathology, male
Research Division:	Biological Sciences
Research Group:	Biochemistry and cell biology
Research Field:	Cell metabolism
Objective Division:	Health
Objective Group:	Clinical health
Objective Field:	Clinical health not elsewhere classified
UTAS Author:	Henstridge, DC (Mr Darren Henstridge)
ID Code:	133334
Year Published:	2012
Web of Science® Times Cited:	174
Deposited By:	Health Sciences
Deposited On:	2019-06-24
Last Modified:	2019-07-23
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