Photocaged Oxytocin and Vasopressin Probes to Decipher Neuropeptide Signalling With High Spatiotemporal Resolution

Area of Science:

• Neuroscience
• Molecular Biology
• Biochemistry

Background:

• Oxytocin/vasopressin (OT/VP) neuropeptide signaling is crucial for social behavior, emotion, learning, and memory.
• Dysregulation of OT/VP signaling is linked to neurological disorders.
• Studying OT/VP signaling in the brain is challenging due to widespread receptor expression, long peptide half-lives, and diffusion.

Purpose of the Study:

• To develop precise, light-triggered methods for releasing OT/VP in the brain.
• To create photolabile protecting groups for controlled neuropeptide activation.
• To investigate the photopharmacological properties of novel OT/VP photoprobes.

Main Methods:

• Investigated three classes of photolabile protecting groups: coumarin, nitrophenylpropyl, and borondipyrromethene.
• Synthesized OT/VP photoprobes using these cages.
• Characterized photopharmacological properties at neuronal receptors (OTR, V1aR, V1bR) using cellular assays, primary rat hippocampal neurons, and ex vivo mouse brain slices.
• Evaluated photocage biocompatibility and compatibility with neuronal experimental setups.

Main Results:

• The coumarin cage demonstrated superior performance, effectively suppressing OT/VP bioactivity until light-induced uncaging.
• Photouncaging enabled on-demand activation of OT/VP receptors with high spatiotemporal resolution.
• The developed photoprobes are biocompatible, easily incorporated into peptides, and compatible with various experimental setups.
• Photo-uncaging can be achieved using inexpensive LED setups or precise two-photon excitation.

Conclusions:

• Developed effective photocages for precise, light-controlled release of OT/VP neuropeptides.
• The coumarin cage offers a promising tool for studying OT/VP signaling with unprecedented spatiotemporal control.
• These photoprobes open new avenues for investigating neuropeptide function in neurological health and disease.