scRNAseq of C3 producing myeloid and astrocytic cells from EAE inflamed murine CNS [scRTL]
Complement component C3 mediates pathology in several CNS neurodegenerative diseases, but the cellular and molecular mechanisms leading to neuronal injury remain unclear. Herein, we examined how C3 deletion affects glial profiles and anterior visual pathway pathology in an animal model of neuroinflammation.  scRNA-seq from mouse brain and optic nerve revealed that C3 expression defined disease-associated glial subtypes which were characterized by increased mTOR activation, cell metabolism, and translation. Deletion of C3 restored these glia towards homeostatic profiles.  Myeloid-derived C3 mediated injury in optic nerve axons and retinal ganglion cells (RGCs) at the peak of EAE.  To elucidate the timing of pathology we examined retinas prior to symptom onset and found reductions in Brn3a, an RGC transcription factor involved in dendritic arborization and protection from apoptosis.  Our study supports a direct role for C3 in activating the mTOR-ribosomal biogenesis axis in glia which subsequently mediate early neuro-axonal stress and later synapse loss. Overall design: From C3 reporter mice at peak of EAE, CNS (brain and spinal cord) were collected from 3 biological replicates, each consisting of 2 animals, and were sorted into 3 populations - Myeloid C3+, Myeloid C3-, and Astrocyte C3+ and C3-. 3 biological replicates, 3 populations per replicate for total of 9 samples