Pro-Inflammatory Protein PSCA Is Upregulated in Neurological Diseases and Targets β2-Subunit-Containing nAChRs

Area of Science:

• Neuroscience
• Molecular Biology
• Structural Biology

Background:

• Prostate stem cell antigen (PSCA) is a Ly6/uPAR protein.
• Soluble PSCA is upregulated in Alzheimer's disease and linked to various neurological conditions.
• PSCA's role in neuroinflammation and its molecular targets remain unclear.

Purpose of the Study:

• To investigate the structure, pharmacology, and inflammatory function of PSCA.
• To explore PSCA's potential role in a broader spectrum of neurological diseases.
• To elucidate PSCA's interaction with neuronal nicotinic acetylcholine receptors (nAChRs).

Main Methods:

• Production of a water-soluble recombinant analog (ws-PSCA).
• Analysis of ws-PSCA structure using Heteronuclear NMR and 15N relaxation measurements.
• Electrophysiological studies in Xenopus oocytes and computational simulations (docking, molecular dynamics) to determine nAChR interactions.

Main Results:

• PSCA expression is upregulated in multiple sclerosis, Huntington's disease, and other neurological disorders.
• ws-PSCA induces pro-inflammatory responses by increasing TNFβ secretion in neurons and astrocytes.
• ws-PSCA inhibits specific nAChR variants (α3β2, α4β2) but not α4β4, suggesting targeting of the β2 subunit.
• Structural analysis revealed a three-finger fold with disordered loops, and simulations predicted binding to α4β2-nAChR at specific interfaces.

Conclusions:

• PSCA plays a role in neuroinflammation and targets specific nAChR subtypes.
• The study provides structural and functional insights into PSCA's molecular interactions.
• Findings offer potential clues for understanding PSCA's involvement in brain function and mental disorders.