Funded Projects

This project aims to develop a next-generation noninvasive neuromodulation system for non-addictive pain treatments. The research team will build an integrated system that uses magnetic resonance image-guided focused ultrasound (MRgFUS) stimulation to target pain regions and circuits in the brain with high precision. The system will use MR imaging to locate three pain targets commonly used in clinical pain treatments, to stimulate those targets with ultrasound, and to monitor responses of nociceptive pain circuits using a functional MRI readout. Three collaborating laboratories will tackle the goals of this project: (Aim 1) Develop focused ultrasound technology for neuromodulation in humans, compatible with the high magnetic fields in an MRI scanner. (Aim 2) Develop MRI technology to find neuromodulation targets, compatible with focused ultrasound transducers. (Aim 3) Validate the complete MRgFUS neuromodulation system in brain pain regions in nonhuman primates. By the end of the project, the research team will have a fully developed and validated MRgFUS system that is ready for pilot clinical trials in pain management.

For patients with neuropathic pain refractory to therapy using small molecules, modulation of specific neural structures in the central or peripheral nervous system can provide effective alternative treatments. While current Food and Drug Administration–approved devices for dorsal root ganglion (DRG) stimulation are safe and effective, there have been an unfortunate number of adverse events associated with pulse generator infections and lead migration. The research team will develop a wireless, millimeter-sized nerve stimulator that can be delivered through the vasculature and stimulate the DRG to alleviate symptoms of neuropathic pain and the associated minimally invasive delivery method. This endovascular nerve stimulation (EVNS) system depends on development and integration of key novel technologies into an endovascular stent. The magnetoelectric transducers and electronic circuits will convert wireless power and data into stimulus patterns that can trigger neural activity in the DRG via miniature electrodes. After chronic demonstration of safety and functionality in large animal models, the team will prepare for regulatory discussions with the FDA. If successful, the EVNS will provide a technology platform for treating other neuropathic pain syndromes. 

Endometriosis is an often-painful disorder in which uterine tissue grows outside the uterus. Treatment of endometriosis-associated pain involves use of opioids in many women. This project aims to study a culprit gene thought to be involved with the disorder (capillary morphogenesis gene or CMG2) as a target for new, nonopioid pain medications. The research will also clarify how CMG2 s affects endometriosis-associated pain to test the effects of new medications for endometriosis pain.

Opioids affect the body by attaching to certain types of receptors that attach to G-proteins (particularly, a subtype called G-alpha). Opioids vary in their ability to provide pain relief as well as in their ability to require more drug to provide a response, known as tolerance. This project will explore the potential of various G-alpha subunits to increase or decrease opioid receptor signaling. The research findings will lay the groundwork for tailoring G-alpha related opioid effects to provide more pain relief while being less addictive.

Functional selectivity is a term used to describe the ability of drugs to differentially regulate the activity of multiple signaling cascades coupled to the receptor. The underlying mechanism for functional selectivity is based upon the formation of ligand-specific receptor conformations that are dependent upon ligand structure. Functional selectivity has the potential to revitalize the drug discovery/development process. Ligands with high efficacy for specific signaling pathways (or specific patterns of signaling) that mediate beneficial effects, and with minimal activity at pathways that lead to adverse effects, are expected to have improved therapeutic efficacy. We propose to demonstrate that ligand efficacy for specific signaling pathways associated with antinociception can be finely tuned by structural modifications to a ligand. We propose to use U50,488 and Salvinorin-A (Sal-A) as scaffolds to develop functionally selective analogs that maintain high efficacy for signaling pathways that lead to antinociception and minimize activity toward anti-antinociceptive signaling pathways.

Masticatory and spontaneous pain associated with temporomandibular joint disorders (TMJD) is a significant contributor to orofacial pain, and current treatments for TMJD pain are unsatisfactory. Pain-related transient receptor potential (TRP) channels, expressed by trigeminal ganglion (TG) sensory neurons, have been implicated in both acute and chronic pain and represent possible targets for anti-pain strategies. Using bite force metrics, we found TMJ inflammation-induced masticatory pain to be significantly, but not fully, reversed in Trpv4 knockout mice, suggesting the residual pain might be mediated by other pain-TRPs. Our gene expression studies demonstrated that TRPV1 and TRPA1 were up-regulated in the TG in response to TMJ inflammation in a Trpv4-dependent manner. We hypothesize that TRPV1 and TRPA1, like TRPV4, contribute to TMJ pain. Our specific aims will examine the contribution of TRPV1, TRPV4, and TRPA1 to pathogenesis of TMJD pathologic pain including assessment of the role of neurogenic inflammation.

Oral cancers are painful and often require use of opioid medications to manage pain. However, the effectiveness of opioids often wanes quickly, and many patients require higher doses because they develop tolerance to these medications. This project will study the potential value of blocking epidermal growth-factor receptors interacting with peripheral nerves to treat oral cancer pain. The findings will advance understanding of the molecular mechanisms underlying oral cancer pain and provide a rationale for repurposing epidermal growth-factor receptor blockers, which is already approved for head and neck cancer treatment for treating oral cancer and associated pain.

This project focuses on identifying and validating a new central analgesic circuit in the brain, based on a highly innovative hypothesis that the strong analgesic effects of general anesthesia (GA) are in part carried out by GA-mediated activation of the endogenous analgesic circuits. Preliminary discovery studies found that a subset of GABAergic neurons located in the central amygdala (CeA) become strongly activated and express high levels of the immediate early gene Fos under GA (hereafter referred to as CeAGA neurons). Furthermore, activation of these neurons exert profound pain-suppressing effects in an acute pain model and a chronic orofacial neuropathic pain model in mice. Based on these exciting preliminary findings, this project will identify and validate CeAGA neurons’ analgesic functions utilizing multiple mouse pain models. Identification of these shared common pathways that need to be suppressed by specific subtypes of CeAGA analgesic neurons will be highly critical for developing precise CeAGA-targeted therapies to treat chronic pain.

Validation of novel pain targets is a critical step toward the development of new non-addictive therapeutic agents for chronic pain management. Recent findings suggest that nerve injury-induced concurrent upregulation of the calcium channel alpha-2delta-1 subunit (CaValpha-2-delta-1) and thrombospondin-4 (TSP4) proteins in sensory and spinal cord neurons contributes to neuropathic pain development. Specifically, induction of aberrant excitatory synapse formation and sensitization of neurotransmission in spinal cord underlies this process; accordingly, a target site has been identified in the TSP4 that plays a critical role in mediating these pathological changes upon interaction with the CaValpha-2-delta-1 protein. This project will validate this novel target site in TSP4 for development of non-addictive pain medications, utilizing multidisciplinary approaches to investigate if blocking and genetic deletion of the target site can block or prevent the development of chronic pain state, aberrant excitatory synapse formation, and spinal cord neuron sensitization after injury in multiple rodent neuropathic pain models.

Postoperative ileus (POI) following gastrointestinal (GI) surgery leads to significant patient morbidity and prolonged hospitalizations. Recent studies have demonstrated that intestinal manipulation and surgical trauma activate inflammatory macrophages (M?) and release inflammatory mediators such as nitric oxide (NO) to inhibit intestinal smooth muscle cells in POI. Intestinal M? are a highly heterogeneous and dynamic population in the innate immune system. Preliminary studies show that transient receptor potential vanilloid 4 (TRPV4) channel, a molecular sensor of tissue damage and inflammation, is exclusively expressed by the F4/80+/CD206+ intestinal anti-inflammatory M2 M?. Activation of TRPV4 produces an intestinal contractile response and improves GI transit in a mouse model of POI. The current proposal aims to elucidate the cellular and molecular mechanisms underlying the activation of TRPV4 in the intestinal M2 M?.

Interstitial cystitis/bladder pain syndrome is a debilitating disease affecting many women. Opioid-based pain management is a common feature of current treatment approaches but is associated with the risk of addiction. The causes of this disorder remain unknown, and no effective treatments are available. This project will provide new insights using genetic, medication-based and other approaches in a mouse model, along with single-cell gene expression studies conducted with cells from mice and human patients who have this condition. The analyses will help provide targeted, safe, and effective treatment approaches for individuals with interstitial cystitis/bladder pain syndrome.

This project will establish a rapid research pipeline for linking plant-derived compounds to nociception (pain) and to G Protein-Coupled Receptors (GPCRs) and ion channels in the druggable human genome. As more than 80% of these membrane proteins are conserved in the C. elegans nematodes, the study will screen for compounds and genes affecting nociception as well as to identify novel ligand-receptor pairs using this model organism. The study will test which understudied GPCRs and ion channels are involved in nociception as well as attraction or repulsion behaviors. This research has the potential to reveal novel ligand-receptor pairs that could serve as new entry points for improved or alternative pain treatments.

Current medications for chronic pain are largely ineffective and rely heavily on opioids, one contributor to the nation’s opioid crisis. The endocannabinoid system that consists of cannabinoid receptors (CB1R and CB2R) and their endogenous ligands is a natural pathway in the human body and has emerged as an alternative target for developing new pain medications with few side effects. Current molecules that bind to CB1R in the brain and spinal cord have psychoactive side effects, limiting their therapeutic use for treating chronic pain. This study aims to develop new molecules to bind to CB1R tightly and selectively, are metabolically stable, and are also unable to enter the brain.