Targeted Complement Inhibition at Synapses Prevents Microglial Synaptic Engulfment and Synapse Loss in Demyelinating Disease (Immunity)

The mechanisms underlying synaptic changes in multiple sclerosis (MS) remain unclear. Werneburg et al. identify microglia-mediated synapse engulfment and synapse loss in MS patients and multiple MS-relevant animal models. Synapse loss can occur early and prior to other MS-relevant pathology and is associated with synapse-localized complement C3. An AAV approach to inhibit C3 protects synapses and preserves circuit function.