Designing chemigenetic DNA nanotrap for norepinephrine dynamic imaging in organelles.

The lack of organelle-targeted neurotransmitter probes limits understanding of their intracellular roles. Here we created an organelle-targeted neurotransmitter nanoprobe using specific molecule-trapped DNA nanostructures for multiple recognition effects. In particular, we designed phenylboronic acid derivatives for chemical reaction and hydroxymethyl groups for forming hydrogen bonding with norepinephrine (NE), which were confined into tetrahedral DNA nanostructures with the optimized spatial effects, achieving the specific and rapid NE identification. Moreover, cyanine 3 providing built-in correction was designed for accurate NE quantification and the HaloTag ligand was synthesized for HaloTag protein targeting onto the organelle membrane, which were bonded to tips of the DNA nanostructure. The developed nanotrap demonstrated high selectivity, fast response (~50 ms), good stability and biocompatibility for organelle NE imaging. Using this tool, we discovered that traumatic brain injury triggers NE bursts in the endoplasmic reticulum, inducing endoplasmic reticulum (ER) stress, altering ER-mitochondrial protein regulation, promoting mitophagy and mitochondrial dysfunction and ultimately causing neuronal death.