Quantitative Analysis of S1PR1 Expression in the Postmortem Multiple Sclerosis Central Nervous System

Area of Science:

• Neuroscience
• Immunology
• Radiochemistry

Background:

• Multiple sclerosis (MS) involves CNS demyelination and inflammation.
• Sphingosine-1-phosphate receptor 1 (S1PR1) modulators impact immune cell trafficking.
• S1PR1 may have non-immune inflammatory roles within the CNS in MS.

Purpose of the Study:

• To quantitatively assess S1PR1 expression in postmortem human CNS tissues from MS cases and healthy controls.
• To explore the role of S1PR1 in the development and progression of demyelinating pathology in MS.
• To evaluate the feasibility of targeting S1PR1 for novel MS imaging strategies.

Main Methods:

• Quantitative autoradiography using the S1PR1-specific radioligand [³H]CS1P1 on human postmortem CNS tissues.
• Immunohistochemistry for S1PR1 and myelin proteins with whole slide scanning.
• Blocking studies with a S1PR1 antagonist (NIBR-0213) to confirm radioligand specificity.

Main Results:

• S1PR1 expression was significantly elevated in MS lesions compared to nonlesion areas and healthy controls.
• Increased binding affinity (Kd) of [³H]CS1P1 to S1PR1 was observed in MS brains (gray and white matter).
• Autoradiography demonstrated S1PR1 activation and increased radioligand uptake in MS CNS lesions.

Conclusions:

• Findings demonstrate S1PR1 activation and increased radioligand uptake in MS CNS lesions.
• Quantitative autoradiography using [³H]CS1P1 on human postmortem tissues shows feasibility for novel MS imaging.
• S1PR1 is implicated in the inflammatory pathology of MS, supporting its potential as an imaging target.