SPP1 and neurodegenerative disease: Osteopontin, encoded by Spp1, is a pro-inflammatory secreted protein which has been shown to inhibit autophagosome-lysosome fusion (Tang et al., 2020) and is thought to play a role in pathogenesis of neurodegenerative diseases or in neuroprotection by regulating the activation and function of microglia (Yu et al., 2017).