How do neurons mature? Discerning factors that control the development of somatosensory neurons.

• Daivik Arora, Biological Sciences, University of Delaware

• Austin Keeler, Biological Sciences, University of Delaware

The brain builds circuits that translate stimuli into appropriate behavioral responses: however, problems during development can lead to dysfunctional pain sensation, such as in chronic pain conditions. When the growth or maturation of pain neurons is disrupted, pain conditions can develop later in life. Pain neuron growth is guided by secreted proteins called trophic cues that help neurons survive a selective competition during development. However, recent work suggests these trophic cues may also help young neurons decide what to become, in other words, what type of pain they will transmit, such as heat, cold, or itch. To understand how trophic cues may control how pain neurons decide this fate, we used mass cytometry to study the populations of peripheral embryonic cultured mouse neurons that will become pain neurons. As they grow, they are exposed to different trophic cues and their expression of protein markers, that tell us their identity, are assessed. I expect to find that each trophic cue results in specific neuron types expanded or diminished after long-term (1 week) exposure. We used a powerful new tool, mass cytometry, that can detect a higher number of proteins than traditional methods, thus it can identify each individual cell based on that cell’s expression of identity markers. The data is separated into each growth condition and analyzed to compare the relative amounts of each population across the different growth conditions to determine how each trophic cue regulates immature pain neuron populations. These results provide basic understanding of the patterns underlying pain neuron development providing a step towards alleviating chronic pain conditions.