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

Abstract

Amyotrophic lateral sclerosis (ALS) is a disease with a resilient neuroinflammatory component caused by activated microglia and infiltrated immune cells. How to successfully balance neuroprotective versus neurotoxic actions through the use of anti-inflammatory agents is still under debate. There has been a boost of awareness regarding the role of extracellular ATP and purinergic receptors in modulating the physiological and pathological mechanisms in the nervous system. Particularly in ALS, it is known that the purinergic ionotropic P2X7 receptor plays a dual role in disease progression by acting at different cellular and molecular levels. In this context, we previously demonstrated that the P2X7 receptor antagonist, brilliant blue G, reduces neuroinflammation and ameliorates some of the pathological features of ALS in the SOD1-G93A mouse model. Here, we test the novel, noncommercially available, and centrally permeant Axxam proprietary P2X7 antagonist, AXX71, in SOD1-G93A mice, by assessing some behavioral and molecular parameters, among which are disease progression, survival, gliosis, and motor neuron wealth. We demonstrate that AXX71 affects the early symptomatic phase of the disease by reducing microglia-related proinflammatory markers and autophagy without affecting the anti-inflammatory markers or motor neuron survival. Our results suggest that P2X7 modulation can be further investigated as a therapeutic strategy in preclinical studies, and exploited in ALS clinical trials.

Purinergic P2X7 Receptor: A Therapeutic Target in Amyotrophic Lateral Sclerosis

“…At a terminal stage, antagonist-treated mice displayed a significant reduction in pro-inflammatory cytokines and autophagy markers compared to vehicle controls. Surprisingly, AXX71 did not affect anti-inflammatory markers, motor neuron survival, or overall lifespan …”

“…These effects could be ameliorated by the use of antagonist A-804598 . Similarly, a recent in vivo study of SOD1 G93A mice found that novel P2X 7 R antagonist AXX71 successfully ameliorated autophagy …”

“…Recently, Axxam SpA published data on its proprietary P2X 7 R antagonist AXX71. It has high potency (IC 50 = 14 nM at human P2X 7 R), does not have activity at other P2X or P2Y receptors, and reaches the brain after intraperitoneal administration . The structure of AXX71 is currently undisclosed.…”

Mitochondrial Damage-Associated Molecular Patterns Content in Extracellular Vesicles Promotes Early Inflammation in Neurodegenerative Disorders

“…On the other hand, increased ATP levels in ALS patients CSF were measured [ 129 ]. Importantly, Apolloni et al demonstrated that the antagonism of P2X7 receptor in a SOD1-G93A mouse model of ALS ameliorates the early symptomatic phase of the disease by reducing microglia-related pro-inflammatory markers and autophagy [ 130 ]. In fact, the activation of P2X7 receptor in SOD1-G93A mouse leads to the increase in autophagic flux in microglia [ 131 ] and increased oxidative stress [ 132 ] concomitantly with the enhancement of pro-inflammatory action of microglia [ 133 ].…”

Mitochondrial Damage-Associated Molecular Patterns Content in Extracellular Vesicles Promotes Early Inflammation in Neurodegenerative Disorders

“…On the other hand, increased ATP levels in ALS patients CSF were measured [125]. Importantly, Apolloni et al demonstrated that the antagonism of P2X7 receptor in a SOD1-G93A mouse model of ALS ameliorates the early symptomatic phase of the disease by reducing microglia-related pro-inflammatory markers and autophagy [126]. In fact, the activation of P2X7 receptor in SOD1-G93A mouse leads to the increase of autophagic flux in microglia [127] and increased oxidative stress [128] concomitantly with the enhancement of pro-inflammatory action of microglia [129].…”