SPP1
Secreted phosphoprotein 1 (Osteopontin)
Also known as: SPP1, OPN, osteopontin, BNSP, BSPI
Biology & Mechanism
SPP1 encodes osteopontin, a secreted glycoprotein and marker of disease-associated microglial states. SPP1-positive microglia represent a subset of activated cells found in close proximity to amyloid plaques and sites of neurodegeneration. SPP1 expression is strongly upregulated in the disease-associated microglia (DAM) signature and in proliferating microglia. Its levels are elevated in CSF of neurodegeneration patients.
Open Questions
- —Is SPP1 upregulation a marker of protective or damaging microglial states?
- —Can SPP1 serve as a blood or CSF biomarker of microglial activation state?
- —What are the downstream signaling pathways activated by osteopontin in the neuroinflammatory context?
Sources
- Disease-associated microglia: a universal response to neurological insults (2017)
Last reviewed: June 1, 2026