Funded Projects

There is a distinct neural ensemble in the brain that encodes the negative affective valence of pain. This project will identify novel targets to treat pain by determining the molecular identity of these BLA nociceptive cells via in situ hybridization and single cell RNAsequencing (scRNA-seq). Resolving the molecular identity of these ACC nociceptive cells will also reveal new targets to treat pain affect. To achieve these results the project will catalog candidate Gi/o-GPCR targets in BLA and ACC, test their utility to treat pain, and verify these new targets have no effect in the brain?s reward and breathing circuitry. The experiments in this project will also evaluate each target for abuse potential and effects on breathing by using behavioral assays for reward processing and whole-body plethysmography, respectively. To evaluate whether our results in rodents are likely to translate clinically, there will be an analysis of expression patterns of these drug targets in human tissue using in situ hybridization.

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.

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.

Pain is a major problem for spinal cord injury (SCI) patients that tends to persist and even worsen with time. No treatments are currently available to consistently relieve pain in SCI patients. This study will investigate the feasibility of Epidural Electrical Stimulation (EES) using the Abbott Proclaim? SCS system with two electrodes to treat neuropathic pain in patients with thoracic spinal cord injury. In this double-blind, prospective, randomized clinical trial, patients with subacute, traumatic, complete thoracic SCIs with American Spinal Injury Association (ASIA) Impairment Scale A will be randomized to receive either ?EES on? (treatment intervention) or ?EES off? (control intervention) of the target regions for pain control (lead overlying the spinal cord anatomy corresponding with their pain distribution) and neurorestoration (lead overlying the conus medullaris) as an adjunct to physical therapy. This study will help determine whether EES can help patients with SCI neuropathic pain and have more widespread clinical applicability.

Multidisciplinary chronic pain treatments show incomplete recovery at the population level because of significant heterogeneity on the individual level in the high impact chronic pain population. Subgroups of individuals either completely respond, do not change, or even worsen following pain management. Therefore, diagnostic biomarker signatures are needed to differentiate high impact chronic pain from low impact chronic pain. This study aims to develop prognostic biomarkers to predict the disease trajectory for individuals with musculoskeletal high-impact chronic pain. These biomarker signatures will integrate central nervous system (CNS), multi-?omic?, sensory, functional, psychosocial, and demographic domains into detection algorithms. Biomarker signatures from the proposed research are intended to facilitate risk and treatment stratification for clinical trial design and to facilitate treatment decisions in clinical practice for patients with musculoskeletal chronic pain.

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.

Opioids and other addictive substances have powerful rewarding properties that drive the development of addiction. They also have aversive properties that motivate their avoidance and protect against addiction. This project will explore the role of Type 2 Taste Receptor proteins (Tas2Rs or T2Rs) in regulating the aversive properties of opioids, potentially establishing an entirely new class of receptors that can be targeted for the development of novel addiction therapeutics.

There is an urgent unmet need for more efficacious analgesics that act via a non-opioid pathway. Mitogen Activated Protein Kinase-interacting kinase 2 (MNK2) is an enzyme that has been implicated in pain signaling, and there is compelling evidence that inhibiting MNK2 has significant pain-reducing effects with few side-effects. Since MNK2 selective inhibitors have not yet been identified, selective inhibition of MNK2 with a small molecule has not been possible. The development of such compounds will enable studies that will illuminate key differences between MNK2 and MNK1. More importantly, from a therapeutic standpoint, highly selective MNK2 inhibitors may prove to have enhanced efficacy and a more favorable side-effect profile than molecules that inhibit both MNK2 and MNK1. This project will support the design and synthesis of at least one MNK2 inhibitor, with >100-fold selectivity over MNK1, that may be developed into a lead compound for treating neuropathic pain.

G-protein coupled receptor 3 (GPR3) is an orphan receptor present in the central nervous system (CNS) that plays important role in many normal physiological functions and is involved in a variety of pathological conditions. Although the brain chemical that activates this receptor has not been identified, work with GPR3 knockout mice has identified GPR3 as a novel drug target for several Central Nervous System (CNS) mediated diseases including neuropathic pain. However, despite the emerging behavioral implications of the GPR3 system, little is known about how GPR3 affects behavior due to the lack of potent and selective chemical probes that allow scientists to examine functioning of the receptor. Recently, two cannabinoid chemicals present in the cannabis plant were discovered as affecting GPR3. This study will modify the chemical structure of these compounds to increase their potency and selectivity so that they may be used as pharmacological tools to investigate the role of GPR3 in modulating pain. In addition, this project focuses on identifying new compounds that show promise for development into therapeutics for the treatment of pain.

Chronic orofacial pain during Temporomandibular Disorders (TMD) and oral cancer is a significant health problem with scarce non-opioid treatment options. This study aims to validate critical regulators of the balance between protective immunity and immunopathology during chronic inflammatory diseases?tumor necrosis factor alpha superfamily members, LIGHT (TNFSF14) and lymphotoxin-beta (LT?) and their receptors, LT?R and Herpes Virus Entry Mediator (HVEM)?as novel therapeutic targets. The study also seeks to determine whether inhibition of LIGHT and LT? signaling prevents the development and inhibits maintenance of chronic TMD and oral cancer pain via peripheral mechanisms involving plasticity of immune, muscle and tumor cells as well as sensory neurons. The study will define the contribution of LIGHT and LT? signaling to TMD-induced excitability of trigeminal sensory neurons innervating the masseter muscle and joint. New validated therapeutic targets for prevention and treatment of orofacial pain that can be peripherally targeted would reduce side effects of current pain medicates related to drug dependence or tolerance.

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.

Mismanagement of orofacial chronic pain, such as temporomandibular joint and muscle disorders (TMJD) and oral cancer, substantially contributes to opioid overuse; overdose-related deaths; and cardiovascular, renal, and neurological complications at epidemic proportions. The current paradigm implies that orofacial conditions could trigger maladaptation of the immune system and plasticity supporting persistent inflammation, which influences the development and maintenance of orofacial chronic pain. LIGHT (TNFSF14) and Lymphotoxin-beta (LT?), members of the tumor necrosis factor superfamily, provide a balance between protective immunity and immunopathology during chronic inflammatory diseases. This project will test the hypothesis that targeting LIGHT and LT? signaling could prevent the development and inhibit the maintenance of chronic pain produced by TMJD and oral cancer, via peripheral mechanisms involving plasticity of immune, stromal, and tumor cells, as well as sensory neurons. The proposed research is significant as it advances our understanding of mechanisms regulating the development and maintenance of orofacial pain and offers new therapeutic targets and an immunotherapeutic approach for preventing and blocking chronic pain during TMJD and oral cancer.

There is increasing evidence that satellite glial cells (SGCs) surrounding neurons in the dorsal root ganglia modulate sensory processing and are important for chronic pain. Tissue inhibitor of metalloproteinase 3 (TIMP3) signaling occurs in SGCs and has unique plethoric functions in inhibiting matrix metalloproteinases, the tumor necrosis factor-?-converting enzyme, and the vascular endothelial growth factor receptor 2, all of which have been implicated in inflammation and pain. This study will test the hypothesis that expression of TIMP3 in SGCs is critical for the neuroimmune homeostasis in sensory ganglia, as well as for the development of pain, and therefore could be a novel therapeutic target for acute and chronic pain. Given the expression of TIMP3 in human SGCs and the strong validation of multiple small molecules targeting TIMP3 signaling, including FDA-approved drugs, in various animal models of pain and in cultured human SGCs, the successful completion of this research project has a high likelihood of rapid translation into therapeutic testing in inflammatory pain conditions that are a risk for opioid abuse.