Spinal cord pathology is ameliorated by P2X7 antagonism in a SOD1-mutant mouse model of amyotrophic lateral sclerosis.

In recent years there has been an increasing awareness of the role of P2X7, a receptor for extracellular ATP, in modulating physiopathological mechanisms in the central nervous system. In particular, P2X7 has been shown to be implicated in neuropsychiatry, chronic pain, neurodegeneration and neuroinflammation. Remarkably, P2X7 has also been shown to be a 'gene modifier' in amyotrophic lateral sclerosis (ALS): the receptor is upregulated in spinal cord microglia in human and rat at advanced stages of the disease; in vitro, activation of P2X7 exacerbates pro-inflammatory responses in microglia that have an ALS phenotype, as well as toxicity towards neuronal cells. Despite this detrimental in vitro role of P2X7, in SOD1-G93A mice lacking P2X7, the clinical onset of ALS was significantly accelerated and disease progression worsened, thus indicating that the receptor might have some beneficial effects, at least at certain stages of disease. In order to clarify this dual action of P2X7 in ALS pathogenesis, in the present work we used the antagonist Brilliant Blue G (BBG), a blood-brain barrier permeable and safe drug that has already been proven to reduce neuroinflammation in traumatic brain injury, cerebral ischemia-reperfusion, neuropathic pain and experimental autoimmune encephalitis. We tested BBG in the SOD1-G93A ALS mouse model at asymptomatic, pre-symptomatic and late pre-symptomatic phases of disease. BBG at late pre-onset significantly enhanced motor neuron survival and reduced microgliosis in lumbar spinal cord, modulating inflammatory markers such as NF-κB, NADPH oxidase 2, interleukin-1β, interleukin-10 and brain-derived neurotrophic factor. This was accompanied by delayed onset and improved general conditions and motor performance, in both male and female mice, although survival appeared unaffected. Our results prove the twofold role of P2X7 in the course of ALS and establish that P2X7 modulation might represent a promising therapeutic strategy by interfering with the neuroinflammatory component of the disease.

Apolloni S ，Amadio S ，Parisi C ，Matteucci A ，Potenza RL ，Armida M ，Popoli P ，D'Ambrosi N ，Volonté C ... -  《-》

Ablation of P2X7 receptor exacerbates gliosis and motoneuron death in the SOD1-G93A mouse model of amyotrophic lateral sclerosis.

Apolloni S ，Amadio S ，Montilli C ，Volonté C ，D'Ambrosi N ... -  《-》

Motor neuron dysfunction in a mouse model of ALS: gender-dependent effect of P2X7 antagonism.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative progressive currently untreatable disease, characterized by selective motor neuron degeneration; the incidence and prevalence of ALS are greater in men than in women. Although some important mechanisms that might contribute to the death of motor neurons have been identified, the mechanisms underlying disease pathophysiology are still uncertain. In particular, the mechanisms underlying the role of gender in ALS and whether treatments should take into account sexual dimorphism remain only partially understood. Recently, the P2X7 receptor for ATP was reported to display neurotoxic potential in motor neuron disorders, and antagonism of the receptor has been suggested to be helpful in these disorders. Studying transgenic mice with superoxide dismutase 1 gene mutations, widely used as model for ALS, may provide a better understanding of pathogenic mechanisms and of toxicity towards motor neurons, also possibly helping to understand whether treatments for ALS should take into account sexual dimorphism. The aim of the work was (1) investigating on gender-dependence of disease progression in the standard model for ALS - the transgenic mouse bearing superoxide dismutase 1 gene mutations - and (2) assessing if a P2X7 receptor antagonist treatment should take into account sexual dimorphism. We evaluated if gender affect the disease course, the motor performance, the weight loss and the lifespan in mice overexpressing mutant superoxide dismutase 1. We measured motor impairment, motor strength and coordination by rotarod and grip strength testing. Further, we assessed if a treatment with the P2X7 receptor antagonist Brilliant Blue G - a dye that can cross the blood-brain barrier, has low toxicity, and has exhibited therapeutic effects in animal models of neurodegenerative diseases - impact on the disease progression, in male and female ALS mice. We found that (1) the onset and the disease progression, and the survival were dependent on gender: male performed worst than female, lost body weight and died before; (2) treatment with the P2X7 receptor antagonist Brilliant Blue G ameliorated the disease progression. The treatment effect was gender-dependent: amelioration was greater in male than in female. In conclusions, we suggest that not only pathogenetic mechanism of motor neuron toxicity but also the drug treatment effectiveness may depend on gender; sexual dimorphism should be considered when investigating on ALS treatment efficacy in the ALS animal model. Our findings also point on the potential relevance of P2X7 receptor antagonism for ALS treatment, and highlight the importance of adopting a sex-specific approach to searching for treatment of ALS.

Cervetto C ，Frattaroli D ，Maura G ，Marcoli M ... -  《-》

The NADPH oxidase pathway is dysregulated by the P2X7 receptor in the SOD1-G93A microglia model of amyotrophic lateral sclerosis.

Apolloni S ，Parisi C ，Pesaresi MG ，Rossi S ，Carrì MT ，Cozzolino M ，Volonté C ，D'Ambrosi N ... -  《-》

Novel P2X7 Antagonist Ameliorates the Early Phase of ALS Disease and Decreases Inflammation and Autophagy in SOD1-G93A Mouse Model.

Apolloni S ，Fabbrizio P ，Amadio S ，Napoli G ，Freschi M ，Sironi F ，Pevarello P ，Tarroni P ，Liberati C ，Bendotti C ，Volonté C ... -  《-》