Ricerc@Sapienza

Amyotrophic lateral sclerosis (ALS) represents the major adult-onset neuron disease leading to motor neuron degeneration, alteration in the neuromuscular junction (NMJ), muscle atrophy, paralysis, and death. In the 20% of cases that show familial inheritance, ALS is linked to mutations in the gene encoding the superoxide dismutase 1 (SOD1). Recent studies on SOD1 G93A mice showed that the communication between nerve and muscle is highly impaired, indicating that Neuromuscular Junction (NMJ) dysfunction precedes the clinical phase of the disease. However, mechanistic insight into how NMJ dysfunction relates to muscle-nerve alteration is incomplete. This is, in part, caused by a lack of robust in vitro models. The main goal of this research is to use a 3D NMJ system to study the physiopathological interplay between nerve and muscle occurring during ALS disease. We propose to define the potential cellular and molecular players involved in the functional short circuit that contributes to the so-called dying-back process. We will define: i) whether altered skeletal muscle impinges motor neuron homeostasis or ii) whether the maintenance of healthy muscle counteracts motor neuron decline. To this purpose, we will use a custom build microfluidic device, containing the main elements forming the NMJ architecture, namely the ex vivo muscle engineered tissue (X-MET), already developed in our laboratory, coupled with motor neuron cell cultures and the terminal Schwann cells (TSC). Based on the comparison between muscle contractile response to direct membrane stimulation and muscle response to indirect nerve stimulation, we will be able to evaluate NMJ functional properties, allowing a deeper analysis of synaptic transmission in the 3D ALS model. This study will provide new insights into the mechanisms that trigger functional denervation and offer the possibility of developing the specific intervention to attenuate NMJ loss and nerve-muscle dysfunction in ALS.