Project Summary / Abstract The long-term goal of this project is to elucidate the basic cellular, molecular, and physiological mechanisms of cold nociception. Thermosensory nociception is a specialized form of somatosensation, essential to the survival of all metazoans, that alerts the organism to potential environmental dangers coupled with pain sensation thereby serving as a protective mechanism for driving adaptive behavioral responses to safeguard against incipient damage. Despite this importance, the fundamental cellular, molecular, and physiological bases of cold nociception remain incompletely understood. Molecularly, transient receptor potential channels (i.e. thermoTRPs) play critical roles in thermosensation either by direct or indirect activation in response to temperature change, however, the mechanisms by which cold temperatures are transformed into ion channel structural alterations to regulate neural activity remain unclear. Similarly, relatively less is known regarding how thermoTRPs may interact with other sensory transduction receptors and downstream signaling pathways to mechanistically regulate cold detection. Neurologically, acute and chronic pain may manifest as altered thermosensory nociception whereby thermal stimuli erroneously engage nociceptive circuitry leading to neuropathic pain. Cold allodynia or hyperalgesia are well-known symptoms of inflammatory and neuropathic pain that have been associated with peripheral nerve injury, multiple sclerosis, fibromyalgia, stroke, and chemotherapy-induced peripheral neuropathy, however, the mechanisms underlying cold sensitization are poorly understood. Here, we will investigate how noxious cold stimulation exerts cellular and physiological effects on membrane properties, cytoskeletal dynamics, and mechanosensory ion channel function. Further, we will characterize non-canonical roles of sensory transduction receptor signaling in regulating cold nociception. Using Drosophila as a model system, we will bi-directionally link experimental and computational approaches involving neurogenetics, high-resolution cellular imaging, in vivo functional imaging, electrophysiology, behavioral assays, and computational biophysically-grounded modeling. The project aims and outcomes of this research will significantly advance our knowledge of cold nociception by addressing three open questions: (1) How do changes in the mechanical and fluidic properties of the membrane and cytoskeleton contribute to cold-evoked behavior? (2) How do mechanoreceptor channels contribute to cold somatosensation? (3) How does a heterogeneous population of sensory transduction receptors, including non-canonical receptor channels and G- protein coupled receptors (GPCRs) contribute to cold sensation? More generally, the bi-directional integration of experimental and computational approaches in a closed-loop investigational strategy is well-suited to transform our understanding of cold nociception by elucidating potentially ...