The Motor Neuron m6A Repertoire Governs Neuronal Homeostasis and Augmented m6A Production Mitigates ALS Symptom Manifestation [snMultiome-seq]

Amyotrophic lateral sclerosis (ALS) is a swiftly progressive and fatal neurodegenerative ailment marked by the degenerative motor neurons (MNs). Why MNs are specifically susceptible in predominantly sporadic cases remains enigmatic. Here, we demonstrated N6-methyladenosine (m6A), an RNA modification catalyzed by the METTL3/METTL14 methyltransferase complex, as a pivotal contributor to ALS pathogenesis. By conditional knockout Mettl14 in murine MNs, we recapitulate almost the full spectrum of ALS disease characteristics. Mechanistically, pervasive m6A hypomethylation triggers dysregulated expression of high-risk genes associated with ALS and an unforeseen reduction of chromatin accessibility in MNs. Additionally, we observed diminished m6A levels in induced pluripotent stem cell (iPSC)-derived MNs from familial and sporadic ALS patients. Restoring m6A equilibrium via a small molecule or gene therapy significantly preserves MNs from degeneration and mitigates motor impairments in ALS iPSC-derived MNs and murine models. Our study presents a substantial stride towards identifying pioneering efficacious ALS therapies via RNA modifications. Overall design: snMultiome-seq: Single nuclei were extracted from P100~P120 Sun1sfGFP; ChAT-Cre; Mettl14floxed (cKO) and Sun1sfGFP; ChAT-Cre (control) lumbar spinal cord. Cholinergic neurons were labeled in GFP and sorted via FACS, and loaded onto 10x Genomics Chromium Next GEM Chip J Single Cell Kit. Join snRNA and scATAV libaries were prepared using 10x Genomics plateform.