Optical Imaging

Cell and Channel Imaging: Our Center houses a multi-photon microscope, super resolution TIRF microscope with STORM capabilities, a super resolution spinning disk microscope, and standard confocal and epifluorescence microscopes, which allow us to investigate the spatial distribution of ion channels at high resolution at the plasma membrane of cultured neurons, as well as investigating trafficking of tagged channels and their partners in real time in multiple neuronal compartments. Through our studies of ion channel trafficking in neurons in vivo, we aim to understand, at the single-molecule level, how the excitable membranes of pain-signaling neurons are built, and how they change in disease.

Imaging the Spinal Cord In Vivo and in Real Time : Our Center has developed the expertise to implant spinal cord window chambers in mice for up to 4 weeks, without damaging the cord or inducing locomotor deficits. This enables repeated imaging of the spinal cord and its vasculature in situ in the same animal, using a multi-photon confocal imaging system (Nikon A1R MP+), which is part of our core infrastructure. Our platform of high-resolution direct imaging of the spinal cord following injury, during recovery, or following therapeutic intervention aims to significantly improve preclinical research and accelerate the pace toward clinical translation.

Understanding Sodium Channel Trafficking and Deployment: Our Center has developed the expertise to investigate insertion of individual sodium channel isoforms channels into neuronal membranes and understand the intracellular dynamics of channel transport. We have, e.g., applied optical pulse chase and single molecule tracking to observe the trajectory of Nav1.6 channels as they are transported from synthesis in the ER to distant locations along the axonal membrane, and demonstrated that mature Nav1.6 channels are preferentially inserted into the axon initial segment membrane via direct vesicular trafficking, and we have shown that channels delivered to the axon are immediately immobilized within the axonal membrane, whereas channels delivered to the soma are often mobile (Akin et al., 2015).

We have now built on this achievement to understand the molecular machinery that controls

sodium channel trafficking in the CNS and PNS in order to develop strategies that can, for e.g., restore conduction in demyelinated axons in pathologies such as MS and SCI where myelin is damaged, and understand the spatial organization and trafficking of sodium channels in nociceptors, and its impact on action potential initiation and propagation.