Mechanisms of Heat Sensing by Nociceptive Vanilloid Receptors

About This Grant

PROJECT SUMMARY Chronic pain affects one in five Americans, yet fewer than half find adequate relief from existing treatments. For severe pain, opioids often remain the primary option, but their overreliance has fueled the ongoing opioid crisis − a nationwide epidemic now in its third wave, according to the CDC. While effective pain therapies are lacking, promising therapeutic targets are abundant. Temperature receptors, such as TRPV1, act as gateway detectors of pain signals, making them ideal targets for developing analgesics that act directly at pain initiation sites. However, targeting these receptors in clinical settings has proven challenging, requiring mode-specific antagonists that selectively inhibit agonist sensitivity while preserving thermal functions. Understanding how these receptors respond to thermal and chemical stimuli is thus crucial for developing effective therapies. We have recently discovered that the gating of temperature receptors is uniquely complex, involving a “suicidal” mechanism where heat-induced opening is inherently coupled with protein unfolding. Their functional states are transient, lasting only milliseconds, posing significant challenges for structural studies. To overcome these obstacles, we propose developing a novel cryo-EM sample preparation device that enables time-resolved cryo-EM imaging to capture transiently active conformations. By integrating this technology with state-of-the-art methods – including ultrafast T- jump patch-clamp recording and ultrasensitive differential scanning calorimetry – we propose studies to elucidate the structural basis of the suicidal mechanism, uncover the molecular pathways underlying heat- induced activation within the receptors, and identify mode-specific conformational states triggered by heat and agonists. The successful completion of this project will advance both the methodology and understanding of thermal transduction and provide essential structural insights to support mode-specific antagonist development targeting temperature receptors. Furthermore, the innovative technology will have broad applications for studying protein dynamics and other temperature-driven biological processes.