Funded Projects

Pain associated with surgery is experienced by millions of patients every year. Although post-surgical pain usually resolves as the surgical site heals, up to half of the patients develop chronic pain after surgery. Opioids remain the mainstay treatment for post-surgical pain which are fraught with serious side-effects and abuse liabilities. The endogenous mechanism that leads to the resolution of post-surgical pain remain unclear, specifically the effects of surgery on the metabolism of sensory neurons and how those changes influence the resolution of post-surgical pain are not known. Preliminary findings suggest that surgical trauma suppresses pyruvate oxidation while increased glutamine catabolism was associated with the resolution of post-surgical pain. This project will test the hypothesis that tissue incision and surgery disrupt the expression of the glutamine transporter ASCT2, which then prevents the resolution of post-incisional pain and aims to validate ASCT2 as a therapeutic target. This project will also employ pharmacological, genetic and animal pain model studies test a novel RNA expression-based strategy to enhance ASCT2 expression in DRG sensory neurons and alleviate postoperative pain in animal model systems. Successful completion of this project would validate ASCT2 as a novel endogenous non-opioid and non-addictive mechanism-based target for the resolution of postoperative pain.

Debilitating neuropathic pain occurs in 40 percent to 70 percent of people who suffer from spinal cord injury (SCI). There are no distinguishing characteristics to identify who will develop neuropathic pain. The objective of this research is to develop a biomarker signature prognostic of SCI-induced neuropathic pain (NP). The aims of the project are to (1) identify autoantibodies in plasma samples from acute SCI patients to CNS autoantigens and determine the relationship between autoantibodies levels to the development of NP, (2) identify the autoantibody combination with maximal prognostic accuracy for the development of NP at six months after SCI, and (3) develop and optimize an assay to simultaneously measure several autoantibodies and independently validate the prognostic efficacy for NP using plasma samples collected prospectively. Establishing a panel will refine the prognostic value of these autoantibodies as biomarkers to detect who are vulnerable to NP and may be used to for development of nonaddictive pain therapeutics.

Activation of immune cells (microglia) in the central nervous system and neuroinflammation have emerged as key drivers of neuropathic pain. These processes can be triggered by release of ATP, the compound that provides energy to many biochemical reactions. The source and mechanism of ATP release are poorly understood but could be targets of novel treatment approaches for neuropathic pain. This project will use genetic, pharmacological, and electrophysiological approaches to determine whether a large pore channel called Swell 1 that spans the cell membrane is the source of ATP release and resulting neuropathic pain and thus could be a treatment target.

Recent studies have reported that neuropathic pain involves changes in the central nervous system that are linked to necroptosis (programmed necrotic cell death) and release of cellular components that create neuroinflammation. Necroptosis is a type of necrotic cell death affected by the protein receptor-interacting serine/threonine-protein kinase 1 (RIPK1 or RIP1). Preliminary studies also indicate that pain increases levels of RIPK1 in key brain regions implicated in pain processing. This project aims to further validate RIPK1 as a target for neuropathic pain using a newly developed positron emission tomography imaging approach. The work will pave the way for new brain-penetrant RIPK1 inhibitors as a safe, effective, and nonaddictive treatment approach for neuropathic pain.

A key marker of inflammation in Osteoarthritis (OA) is accompanied by significantly increased sensory innervation within the diseased joint. This study aims to validate the hypothesis that defective bone resorbing cells are responsible for the enlarged bone cavity, giving rise to the inflammatory marker causing further increases in levels sensory innervation and resulting in increased OA pain perception.

One of the most debilitating consequences of spinal cord injury is the development of chronic neuropathic pain, which is difficult to manage with existing pain treatments. Animal models and behavioral assays that better reflect the conditions in humans are urgently needed to help in identification of novel pain treatments. This project aims to develop a new model of spinal cord injury-related neuropathic pain using pigs, because they are similar to humans in anatomy, size, metabolism, physiology, and the way their bodies process drugs.

Although opioid-based analgesics have been proven effective in reducing the intensity of pain for many neuropathic pain conditions, their clinical utility is grossly limited due to the substantial risks involved in such therapy, including nausea, constipation, physical dependence, tolerance, and respiratory depression. Cumulative evidence suggests that human Mas-related G protein-coupled receptor X1 (MRGPRX1) is a promising target for pain with limited side effects due to its restricted expression in nociceptors within the peripheral nervous system; however, direct activation of MRGPRX1 at peripheral terminals is expected to induce itch side effects, limiting the therapeutic utility of orthosteric MRGPRX1 agonists. This finding led to the exploration of positive allosteric modulators (PAMs) of MRGPRX1 to potentiate the effects of the endogenous agonists at the central terminals of sensory neurons without activating peripheral MRGPRX1. An intrathecal injection of a prototype MRGPRX1 PAM, ML382, effectively attenuated evoked, persistent, and spontaneous pain without causing itch side effects. The goal of this study is to develop a CNS-penetrant small-molecule MRGPRX1 PAM that can be given orally to treat neuropathic pain conditions.

As many as 64% of patients with Temporomandibular Joint Disorders (TMJDs) report symptoms consistent with Irritable Bowel Syndrome (IBS). However the underlying connection between these comorbid conditions is unclear and treatment options are poor. As such, pain management for these Chronic Overlapping Pain Conditions (COPCs) is a challenge for physicians and patients. This project will determine whether the convergence of pain from different peripheral tissues and perceived stress occurs in the brain and elicits a change in central neural processing of painful stimuli. This project will identify and validate specific lipids, enzymes and metabolic pathways that change expression in the brain during the transition from acute to chronic overlapping pain that can be therapeutically targeted to treat COPCs. Multi-disciplinary approaches will be used to combine brain imaging, visualization of spatial distribution of molecules, genetics, pharmacological and behavioral research techniques.

This project aims to develop and clinically validate a 64-channel spinal cord stimulation therapy for treating chronic neuropathic pain of the lower extremities, groin, and lower back. With an increased channel count and the ability to precisely target medial and lateral structures of the spinal cord, the system will treat chronic pain with greater efficacy and reduced side effects. This project will pursue a safe, effective, and non-addictive treatment for neuropathic pain through the testing of enhanced HD64 active leads to be manufactured under GMP regulations. The leads will then undergo electrical, mechanical, biocompatibility, and sterilization testing before being tested in a 10-subject early feasibility study.

Migraine is the most common neurological disorder. Currently available treatments fail to effectively manage migraine in most patients. Development of new therapeutics has been slow due in large part to a poor understanding of the underlying pathology of migraine. Endogenous proteases, released in the meninges by resident mast cells, have been proposed as a potential driver of migraine pain via an action on protease activated receptor type 2 (PAR2). The central hypothesis is that PAR2 expression in nociceptors that project to the meninges plays a key role in the pathogenesis of migraine pain. The aims are to: 1) use the established PAR2 development pipeline to design new PAR2 antagonists with improved drug-like properties; 2) use pharmacological tools in a novel mouse migraine model to further understand the potential role of PAR2 in migraine; and 3) use mouse genetics to study the cell type–specific role of PAR2 in migraine pain.

Chronic pain is maintained, in part, by persistent changes in sensory neurons, including a pathological increase in peptides derived from the neurosecretory protein VGF (non-acronymic). Preliminary findings show that the C-terminal VGF peptide, TLQP-62, contributes to spinal cord neuroplasticity and that TLQP-62 immunoneutralization attenuates established mechanical hypersensitivity in a traumatic nerve injury model of neuropathic pain. This project will test the hypothesis that spinal cord TLQP-62 signaling can be targeted for the development of new chronic pain treatments through immunoneutralization and/or receptor inhibition. It will pursue discovery and validation of TLQP-62-based therapeutic interventions along two parallel lines: identification of TLQP-62 receptor(s) and validation of anti-TLQP-62 antibodies as a potential biological therapeutic option for chronic neuropathic pain conditions.

Effective development of non-addictive therapies for pain requires animal models that reflect the human condition. Unfortunately, currently used models have limitations and have not always done a good job of predicting what will work in human patients. This project will refine a new way of measuring pain-related behaviors in mice that takes advantage of more natural mouse behavior and is less influenced by experimenter biases and artifacts. The research will verify that the promising results hold up in several different types of pain and that different classes of clinically used pain medications are effective. They will also make sure the data can be reproduced by an outside laboratory. If successful, this will support the use of this new read-out for future pain therapy development.