Day 3 Nanosymposium Highlight: Connect-Seq
Just after lunch on Tuesday, I watched a nanosymposium talk given by Naresh Hanchate, a postdoc in Linda Buck’s lab at the Fred Hutchinson Cancer Center at the University of Washington in Seattle. There, he presented a new method he developed, which he called Connect-Seq.
Connect-Seq visual summary.
This method uses a combination of single cell RNA-sequencing and viral tracing to figure out which cells in one part of the brain connect to which cells in another. He was very interested in neurons in the amygdalo-piriform transition area (APir) innervating CRH neurons in the hypothalamus, which control stress hormone release after smelling an innately fearful scent, like trimethylthiazoline, an odor given off by foxes. To figure out the properties of these APir neurons, he specifically infected hypothalamic CRH neurons with a pseudorabies virus, which can actually travel backwards and infect their upstream neurons.
Using microfluidic sorting, he was then able to isolate these cells into their own individual wells, and then he could perform RNA sequencing on these isolated single cells. This then allowed him to find the overall gene expression in each cell, creating a complete molecular map of each cell they isolated.
This map showed a number of new and interesting things about these upstream cells that were previously unknown. The most interesting, by far, are the range of signaling molecules they use. Each cell does not simply express one neurotransmitter gene, as expected, but instead a wide range of different signaling molecules. These signaling molecules are not just GABA, glutamate, or the traditional neuromodulators like serotonin and dopamine. Instead, they include compounds like CART, vasopressin, adrenomedullin, and other obscure, poorly studied proteins.
The implications of these results could be further-reaching than they may appear. Release of stress hormones may be less controlled by traditional signals from upstream neurons, but instead could result from less familiar methods that could provide fertile ground for future research, and could allow for a far richer understanding of both the intrinsic dynamics of stress and how we respond.