Mechanotransduction, or the mechanisms by which cells convert mechanical stimuli into electrical activity, is a process conserved across all domains of life and is a necessary facet of our interaction with the world. However, despite its ubiquity and importance, mechanotransduction is not well understood at a molecular level. Leeches in the genus Hirudo, commonly known as medicinal leeches, have been long used as a model system for neurobiology and as a result the characteristics of the neurons in the segmentally iterated ganglia of the ventral nerve cord have been well established. To determine what genes might mediate the differences between the mechanosensitive and non-mechanosensitive neurons in these ganglia, I and others carried out a transcriptomic analysis of five different cell types in the Hirudo ganglion. One major signature that arose from this analysis was the differential expression of several transcripts encoding channels similar to those that have been shown to be mechanosensitive in other systems. However, our system would not only allow us to ground- truth whether these channels confer mechanosensitivity, but also would determine the nature of this process, as the three different mechanosensitive neurons in the leech ganglion exhibit different responses to touch. Specifically, I plan to: 1) Determine the effect of the loss of these channels on neuronal function by transcript knock-down in Hirudo body wall preparations and in vivo neuronal culture; 2) Describe the developmental trajectory and organismal relevance of these genes using Helobdella, another leech and well-established developmental model system; and 3) Directly determine whether a subset of these channels confers mechanosensitivity in mammalian cell culture through expression of the full-length protein and subsequent functional assays.
My project aims to improve our understanding of mechanosensation, a process that is well- conserved and essential for interaction with the outside world, and is yet not well understood at a molecular level. As aberrations in mechanosensation can lead to debilitating diseases such as chronic pain and chronic itch, a better understanding of this process will greatly benefit human health. I plan to investigate the processes underlying mechanotransduction by using the model system of the medicinal leech ventral nerve cord ganglion, which allows me to determine the transcriptomes of different neurons (both mechanosensitive and not) and to begin to determine what transcripts are necessary for mechanotransduction in this animal and hopefully others as well.
| Heath-Heckman, Elizabeth A C (2016) The Metronome of Symbiosis: Interactions Between Microbes and the Host Circadian Clock. Integr Comp Biol 56:776-783 |
