Expression Profile Study of Macrophages From Patients Affected by Amyotrophic Lateral Sclerosis (ALS) or Other Related Motor Impairments

Amyotrophic Lateral Sclerosis (ALS) is the most common motor neuron disease in adults affecting upper and lower motor neurons resulting in progressive muscle atrophy and paralysis of the patients within 2 to 5 years. The majority of ALS cases are sporadic (SALS), 5 to 10% are familial forms (FALS). In France, the most frequent mutation is an intronic hexanucleotide expansion in the C9orf72 gene, representing 46% of FALS followed by mutations in the first discovered ALS gene, SOD1 accounting for around 10% of FALS. Using mutant SOD1 ALS mouse models, the investigators and others have shown that motor neurons degenerated through a non-cell autonomous mechanism involving microglial cells. Microglial cells are the macrophages of the central nervous system (CNS) capable of producing neurotrophic or neurotoxic factors. Microglial cells are part of the myeloid lineage like macrophages at the periphery, however these two cell types have different developmental origins and are in different environments. Spinal motor neurons are particular neurons since their cell body is in the CNS, and therefore surrounded by microglial cells, while their axon extends at the periphery and is therefore in contact with peripheral macrophages. The investigators have shown that (i) peripheral macrophages in affected peripheral nerves of ALS mouse models and ALS patient post-mortem tissues were activated, (ii) in ALS mouse models, both microglial cells but also peripheral macrophages participated in disease progression and (iii) peripheral macrophages were able to influence microglial cell reactivity.

The working hypothesis is that peripheral macrophages are themselves (and not just microglial cells) involved in ALS and with this project the investigators want to compare macrophages from ALS patients and controls using macrophages derived from blood monocytes. The aim is to analyze the macrophage transcriptome and protein markers of Amyotrophic Lateral Sclerosis (ALS) patients compared to controls (non-affected individuals, patients with other motor impairments) and asymptomatic ALS gene carriers, to find new pathways to target and disease biomarkers.