The PGRMC1 Protein Level Correlates with the Binding Activity of a Sigma-2 Fluorescent Probe (SW120) in Rat Brain Cells

Abstract

Purpose: We examined the progesterone receptor membrane component 1 (PGRMC1) protein expression in rat brain cells as the prerequisite step to understand the biology of PGRMC1 in the central nervous system (CNS). We also performed correlation studies between the PGRMC1 protein level and the binding activity of a sigma-2 fluorescent probe, SW120, in order to explore the possibility of using sigma-2 radiotracer of positron emission tomography (PET) to noninvasively image the CNS.

Procedures: Embryonic primary neurons, astrocytes, oligodendrocytes, and microglia cells were cultured. Immunocytochemistry, Western blot, and SW120 staining were performed in these cells.

Results: The protein expression of PGRMC1 determined by immunocytochemistry and SW120 staining is prominent in neurons and relatively low in astrocytes, oligodendrocytes, and microglia cells. The PGRMC1 expression level correlates with the binding activity of SW120 in rat brain cells.

Conclusions: The sigma-2 receptor PET radiotracer can be potentially used to noninvasively image neuron/synapse densities in the CNS.

Keywords: Fluorescent probe; Neuron; Progesterone receptor membrane component 1 (PGRMC1); Sigma-2 receptor; The central nervous system.