Noninvasive Imaging of Transgene Expression in Neurons Using Chemical Exchange Saturation Transfer MRI

Area of Science:

• Neuroscience
• Biomedical Imaging
• Gene Therapy

Background:

• Gene therapy for brain diseases requires noninvasive methods for monitoring gene expression.
• Conventional reporter gene imaging methods have limitations for longitudinal in vivo studies.
• Chemical Exchange Saturation Transfer (CEST) Magnetic Resonance Imaging (MRI) offers noninvasive imaging with depth penetration and specificity.

Purpose of the Study:

• To explore the potential of CEST-MRI for monitoring gene expression specifically in neurons.
• To develop and evaluate a novel CEST polypeptide reporter for in vivo gene expression tracking.

Main Methods:

• Designed a CEST polypeptide reporter (150 arginine residues) for gene expression.
• Delivered the reporter gene into the living brain via viral vectors.
• Conducted longitudinal CEST-MRI studies at 1 and 2 months post-injection.
• Confirmed neuronal expression using histological analysis with a td-Tomato fluorophore.

Main Results:

• Specific CEST signals were observable in the brain at 1 and 2 months post-injection.
• CEST contrast showed distinct peaks at 0.75 and 1.75 ppm, corresponding to expected proton frequencies.
• Histology confirmed specific neuronal transgene expression.

Conclusions:

• A neuron-specific CEST-MRI reporter gene was successfully developed and evaluated.
• This noninvasive imaging approach can monitor gene expression in neurons.
• The findings support the development of advanced gene therapies for neurological disorders.