C9orf72 and neurodegenerative disease: Furthermore, microglia in co-culture expressed essential microglia-specific markers (namely, MERTK, GPR34, PROS1, C1QA, GAS6, and P2RY12), as well as genes relevant for major neurodegenerative diseases [namely, AD-related genes (APP, PICALM, and CD33); PD-related genes (PARK15, PINK1, SNCA, and DJ-1); and MND/amyotrophic lateral sclerosis-related genes (C9orf72, TDP43, and SOD1)], suggesting that the developed co-culture model could be useful to investigate the effects of several genes associated with highly debilitating neurodegenerative diseases.