A versatile cholera toxin conjugate for neuronal targeting and tracing
Jessica L Haigh1, Daniel J Williamson, Emma Poole
1School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK. w.b.turnbull@leeds.ac.uk.
Chemical Communications (Cambridge, England)
|May 2, 2020
Summary
A novel azido-CTB tracer allows rapid in vivo detection of neural pathways using click chemistry. This method eliminates the need for antibodies and preserves ultrastructure for enhanced neuronal tracing.
Area of Science:
- Neuroscience
- Bioconjugation Chemistry
- Nanotechnology
Background:
- Neuronal tracing is crucial for understanding brain and spinal cord networks.
- Cholera toxin B subunit (CTB) is a common tracer but requires antibody-based detection.
- Current methods can be limited by the need for immunohistochemistry and potential ultrastructural damage.
Purpose of the Study:
- To develop a novel neuronal tracer based on CTB with enhanced detection capabilities.
- To utilize click chemistry for rapid in vivo detection of the modified tracer.
- To create a nano-conjugate for improved visualization and tracing flexibility.
Main Methods:
- Incorporation of non-canonical azido amino acids into CTB (azido-CTB).
- Attachment of cadmium selenide/zinc sulfide (CdSe/ZnS) nanoparticles to azido-CTB via click chemistry (strain-promoted alkyne-azide cycloaddition).
- Intramuscular tongue injection in vivo and detection using light and electron microscopy with silver enhancement.
Main Results:
- Azido-CTB enabled rapid in vivo detection via click chemistry, eliminating antibody requirement.
- The nano-conjugate was successfully detected in the brainstem following tongue injection.
- The method maintained ultrastructure integrity as it did not require membrane permeabilization.
Conclusions:
- Azido-CTB represents a significant advancement in neuronal tracing technology.
- Click chemistry offers a versatile platform for modifying CTB as a tracer and delivery vehicle.
- This approach enhances the utility of CTB for neuroanatomical studies and potentially therapeutic applications.
