In contrast, expression of homeostatic markers such as CX3CR1 and TGFBR1, as well as MERTK were unaffected by in vitro α-syn PFF exposure (Supplementary Fig. 10), suggesting α-syn fibrils are direct drivers of some, but not all, microglial transcriptomic changes in late-stage Parkinson’s disease/Lewy body dementia. Here, MERTK is linked to Lewy body dementia.