Modulation of Astrocytic Mitochondrial Function by Dichloroacetate Improves Survival and Motor Performance in Inherited Amyotrophic Lateral Sclerosis Ernesto Miquel1., Adriana Cassina2,3., Laura Martı´nez-Palma 1 , Carmen Bolatto1, Emiliano Trı´as4, Mandi Gandelman 1 , Rafael Radi2,3, Luis Barbeito5,3, Patricia Cassina1,3* 1 Departamento de Histolog´ıa y Embriolog´ıa, Facultad de Medicina, Universidad de la Repu´ blica, Montevideo, Uruguay, 2 Departamento de Bioqu´ımica, Facultad de Medicina, Universidad de la Repu´ blica, Montevideo, Uruguay, 3 CEINBIO, Facultad de Medicina, Universidad de la Repu´ blica, Montevideo, Uruguay, 4 Instituto de Investigaciones Biol o´gicas Clemente Estable, Montevideo, Uruguay, 5 Institut Pasteur de Montevideo, Montevideo, Uruguay Abstract Mitochondrial dysfunction is one of the pathogenic mechanisms that lead to neurodegeneration in Amyotrophic Lateral Sclerosis (ALS). Astrocytes expressing the ALS-linked SOD1G93A mutation display a decreased mitochondrial respiratory capacity associated to phenotypic changes that cause them to induce motor neuron death. Astrocyte-mediated toxicity can be prevented by mitochondria-targeted antioxidants, indicating a critical role of mitochondria in the neurotoxic phenotype. However, it is presently unknown whether drugs currently used to stimulate mitochondrial metabolism can also modulate ALS progression. Here, we tested the disease-modifying effect of dichloroacetate (DCA), an orphan drug that improves the functional status of mitochondria through the stimulation of the pyruvate dehydrogenase complex activity (PDH). Applied to astrocyte cultures isolated from rats expressing the SOD1G93A mutation, DCA reduced phosphorylation of PDH and improved mitochondrial coupling as expressed by the respiratory control ratio (RCR). Notably, DCA completely prevented the toxicity of SOD1G93A astrocytes to motor neurons in coculture conditions. Chronic administration of DCA (500 mg/L) in the drinking water of mice expressing the SOD1G93A mutation increased survival by 2 weeks compared to untreated mice. Systemic DCA also normalized the reduced RCR value measured in lumbar spinal cord tissue of diseased SOD1G93A mice. A remarkable effect of DCA was the improvement of grip strength performance at the end stage of the disease, which correlated with a recovery of the neuromuscular junction area in extensor digitorum longus muscles. Systemic DCA also decreased astrocyte reactivity and prevented motor neuron loss in SOD1G93A mice. Taken together, our results indicate that improvement of the mitochondrial redox status by DCA leads to a disease-modifying effect, further supporting the therapeutic potential of mitochondria-targeted drugs in ALS. Citation: Miquel E, Cassina A, Mart´ınez-Palma L, Bolatto C, Tr´ıas E, et al. (2012) Modulation of Astrocytic Mitochondrial Function by Dichloroacetate Improves Survival and Motor Performance in Inherited Amyotrophic Lateral Sclerosis. PLoS ONE 7(4): e34776. doi:10.1371/journal.pone.0034776 Editor: Sergio T. Ferreira, Federal University of Rio de Janeiro, Brazil Received December 22, 2011; Accepted March 5, 2012; Published April 3, 2012 Copyright: 2012 Miquel et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by grants from Amyotrophic Lateral Sclerosis Association (ALSA, www.alsa.org), Grant #1734 to PC; Comisio´ n Sectorial de Investigacio´ n Cient´ıfica-Universidad de la Repu´ blica, Uruguay (CSIC, www.csic.edu.uy) and Agencia Nacional de Investigacio´ n e Innovacio´ n, Uruguay (ANII, www. anii.org.uy) to RR and Programa para el Desarrollo de las Ciencias Ba´sicas, Uruguay (PEDECIBA, www.pedeciba.edu.uy). EM is recipient of a fellowship from ANII. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: pcassina@fmed.edu.uy . These authors contributed equally to this work. Introduction ALS is a fatal paralytic neurodegenerative disease characterized by motor neuron loss, which leads to death within 3–5 years of diagnosis. No therapy is available other than riluzole, which extends the lifespan of patients by only 3–6 months [1]. Mitochondrial dysfunction can contribute to motor neuron degeneration in ALS and description of mitochondrial alterations have been fully documented in the spinal cord and the muscle from patients and animal models linked to SOD mutations (for review see [2,3]). Astrocytes from rats expressing SOD1G93A display reduced mitochondrial ability to synthesize ATP and produce increased levels of nitric oxide [4], superoxide and peroxynitrite [5] and accordingly, these effects can be reverted with mitochondria-targeted antioxidants [5]. Interestingly, mito- chondrial dysfunction in astrocytes is associated to neurotoxic phenotypic changes that reduce motor neuron survival [5]. Astrocytes surrounding motor neurons are known to modulate ALS progression. Indeed, analyses of chimeric mice composed of mixtures of normal and mutated SOD1–expressing cells have offered evidence that motor neuron death is non–cell-autonomous [6]. Restricted mutated SOD1 expression in astrocytes is not sufficient for disease development [7]. However, selective reduction of mutated SOD1 in astrocytes increases disease duration after onset as determined by mating mice expressing mutated SOD1 transgenes flanked by lox sites to mice carrying a Cre-encoding sequence under control of the promoter from GFAP [8]. This is accompanied by delayed microglial activation, in accordance with studies using the same technology for microglia [9]. Damage induced by mutated SOD1 in astrocytes determines a phenotype that is neurotoxic for motor neurons in culture and may account for the role of astrocytes in disease progression [4,10,11]. Indeed, the recent isolation of astrocytes with aberrant PLoS ONE | www.plosone.org 1 April 2012 | Volume 7 | Issue 4 | e34776