Expression of heat-shock/stress proteins in Duchenne muscular dystrophy

Abstract

Heat-shock/stress proteins (HSPs) are induced in response to stressful conditions and are essential for survival during and after cellular stress. We investigated whether dystrophin deficiency in muscle from Duchenne muscular dystrophy (DMD) patients induces HSPs. Immunohistochemical studies were performed on cryosections from normal muscle, heat-shocked muscle, and muscle from patients with DMD, dermatomyositis, and mitochondrial myopathy using antibodies against HSP 72/73, HSP 72, HSP 90, groEL (HSP 65 homologue), and ubiquitin. Computer-assisted image processing revealed a significant (P < 0.05) induction of HSP 72/73, 72, 65, and ubiquitin in hypercontracted fibers; HSP 90 and ubiquitin in regenerating fibers; and ubiquitin in macrophage invaded necrotic fibers of DMD muscle. No significant induction of HSPs was observed in dermatomyositis or mitochondrial myopathies. The stress response induced in DMD may relate to the metabolic stress characteristic of the disease and could represent an autoprotective mechanism. Manipulation of this protective response may reduce injury and have potential therapeutic application.