P2RX7 and neurodegenerative disease: In contrast, the SOD1-G93A protein has recently been shown to be rapidly released into the extracellular space upon P2X7 activation and is then re-uptaken by naïve NSC-34 cells or microglia cell lines to induce endoplasmic reticulum stress and TNF-α release, which mediate neurodegenerative disease and neuroinflammation-related ALS events respectively (213).