GPNMB
Glycoprotein NMB (Osteoactivin)
Also known as: GPNMB, osteoactivin, DC-HIL, NMB
Biology & Mechanism
GPNMB is a lysosomal glycoprotein expressed on microglia that is upregulated in disease-associated and lipid-laden microglial states. GPNMB is co-regulated with progranulin (GRN) and both are involved in microglial lysosomal function. Elevated GPNMB has been observed in Parkinson's disease brain and in GBA1-related lipid storage contexts. GPNMB may be shed as a soluble form and could serve as a biomarker of microglial lysosomal stress.
Open Questions
- —What is the precise lysosomal function of GPNMB in microglia?
- —Can soluble GPNMB levels serve as a biomarker of microglial lysosomal stress in neurodegenerative diseases?
- —Is GPNMB upregulation a compensatory or pathological response in lipid-laden microglia?
Sources
- Elevated GPNMB in PD brain corresponds to glycolipid storage defects (2022)
Last reviewed: June 1, 2026