PDGFRB and amyotrophic lateral sclerosis: In mouse models of ALS [46, 66, 67] and in pericyte-deficient mice with disrupted PDGFRβ signaling in pericytes [63], BSCB disruption with erythrocyte extravasation and/or motor neuron accumulation of extravasated plasma-proteins such as thrombin and fibrin precedes motor neuron injury.