A Genetically Engineered Reporter System Designed for ²H-MRI Allows Quantitative In Vivo Mapping of Transgene...

Area of Science:

• Molecular Imaging
• Biophysics
• Medical Physics

Background:

• Quantitative spatial information on subcellular processes in deep tissues using molecular magnetic resonance imaging (MRI) is challenging.
• Quantifying genetically engineered MRI reporter readouts further complicates this imaging task.

Purpose of the Study:

• To develop a molecular system for quantitative 2H-MRI mapping of a gene reporter.
• To overcome the limitations of current MRI techniques in deep tissue imaging and reporter gene quantification.

Main Methods:

• Synthesis of deuterated thymidine (d3-thy) with a distinct 2H-NMR signal.
• Spectral resolution of 2H NMR signals from d3-thy and HDO for quantification.
• In vivo mapping of d3-thy accumulation in cells expressing the human thymidine kinase 1 (hTK1) transgene using 2H-MRI.

Main Results:

• Successfully synthesized d3-thy with a characteristic 2H-NMR singlet peak.
• Demonstrated spectral resolution and quantification of d3-thy concentration relative to HDO in vivo.
• Successfully mapped the accumulation of d3-thy in hTK1-expressing cells using 2H-MRI.

Conclusions:

• The d3-thy/hTK1 pair serves as an effective reporter probe/reporter gene system for quantitative transgene expression mapping with MRI.
• 2H-MRI molecular imaging holds significant potential for monitoring gene reporters and other biological targets in vivo.
• This approach enables quantitative imaging of unmodified reporter probes and proteins, advancing molecular imaging capabilities.