Funded Projects

Dorsal root ganglion (DRG) neuronal hyperexcitability is central to the pathology of neuropathic pain and is a target for local anesthetics, even though the efficacy of local anesthetic patches has been mixed. The coordinated movement of ion channels, especially voltage-dependent sodium channels, from intracellular pools to the sites of nerve injury has been suggested to be an underlying cause of electrogenesis and ectopic firing in neuropathic pain conditions. Recent studies identified Magi1 as a scaffold protein responsible for sodium channel targeting and membrane stabilization in DRG neurons. This project will determine whether reducing the expression Magi1 could disrupt intracellular trafficking of sodium channels in DRG neurons under neuropathic injury conditions, and could therefore serve as a potential therapeutic target for neuropathic pain.

A substantial proportion of Americans seeking emergency care after traumatic stress exposure (TSE) are at a high risk of chronic pain and opioid use/misuse. Physiologic systems involved in the stress response could possibly play a critical role in the development of chronic pain after TSE. FK506-binding protein 51 (FKBP51) is an intracellular protein known to affect glucocorticoid negative feedback inhibition and component of stress response, provides an important non-opioid therapeutic target for such chronic pain. This project will test the hypothesis that functional inhibition of FKBP51 prevents or reduces enduring stress-induced hyperalgesia in a timing, dose, and duration-dependent manner in animal models of single prolonged stress alone and in combination with surgery. This project will also test if FKBP51 inhibition enhances recovery following TSE via reduction in pro-inflammatory responses in peripheral and central tissues. It will also test whether FKBP51 inhibition effects cardiotoxicity or addiction. Completion of these studies will increase understanding of FKBP51 as a novel therapeutic target for the prevention of chronic pain and opioid use/misuse resulting from TSE.

Head and neck cancer is particularly susceptible to nociceptive and neuropathic pains because it is dense with sensitive anatomic structures and richly innervated. Transcranial magnetic resonance imaging–guided focused ultrasound (FUS) is a new stereotactic modality capable of delivering high-intensity energy through the intact human skull with submillimeter precision. This clinical trial will target the spinothalamic and spinoreticular pain circuits by unilateral FUS mesencephalotomy, an effective procedure for cancer pain but limited by the accuracy of its era. The primary aim is to assess the safety and preliminary effectiveness in six head and neck cancer patients with opioid-resistant pain. Researchers will investigate the potential mechanism of pain relief as the mesencephalotomy target involves the confluence of the ascending and descending pain systems. Aims 2 and 3 will investigate these systems with electrophysiology specific for the spinothalamic tract and carfentenil positron emission tomography imaging that measures the brain’s endogenous opioids.

Sickle cell disease is an inherited blood disorder affecting about 100,000 Americans and over 20 million people worldwide. It is caused by a mutation in the gene for beta-globin that results in the characteristic sickled shape of red blood cells, life-long severe pain, and shortened lifespan. Painful episodes that require hospitalization and, in many cases, opioid treatment, are a hallmark of sickle cell disease. The source of these painful episodes remains unclear, and it is also unknown why pain severity varies so much among affected individuals. This project will identify novel, non-opioid targets to reduce sickle cell-related pain and search for biomarkers to help clinicians predict which individuals are at risk for increased pain, thereby improving health outcomes for people with sickle cell disease.

Osteoarthritis (OA) is the most common form of arthritis and a leading cause of pain and disability. Current challenges of managing OA are that there is no OA disease-modifying drug available, there are few effective treatment strategies, and there is an over-reliance on the use of opioids to manage OA-related joint pain. This project aims to validate vascular endothelial growth factor receptors 1 and 2 (VEGFR 1 receptor = Flt1) and (VEGFR 2 receptor = Flk1) as novel therapeutic targets for OA. This is based on a hypothesis that blocking these two specific receptors of VEGF will inhibit cartilage tissue degeneration and alleviate pain symptoms. This study will test the role of VEGFR-1 and -2 in multiple OA animal models using multiple available VEGF inhibitor molecules. The findings from these studies will develop a rationale for future clinical trials to target VEGFR-1 and -2 for OA patients and develop a novel non-addictive treatment for both joint pain and OA pathology.

Many chronic pain conditions are dependent upon activity of the sympathetic nervous system. Sympathetic blockade is used clinically in chronic pain conditions, but the clinical and preclinical evidence for this practice is incomplete. We propose that certain pathological pain conditions require intact sympathetic innervation of the sensory nervous system at the level of the dorsal root ganglion (DRG) and that release of sympathetic transmitters enhances local inflammation and leads to pain. Our preliminary data show large, rapid, and long-lasting reduction of pain behaviors and inflammatory responses following a"microsympathectomy" (mSYMPX) in both neuropathic and inflammatory pain models. Our aims are to: 1) characterize the effects of mSYMPX on pain and on local inflammation in the DRG; 2) explore the molecular mechanisms for sympathetic regulation of inflammatory responses in the DRG; and 3) assess the functional role of sympathetic transmitters in the sympathetically mediated inflammatory responses in the DRG.

Taxanes are among the most effective chemotherapeutic agents and are frequently used in the treatment of early stage and metastatic breast cancer. However, they are known to produce a pain condition known as Chemotherapy-Induced Peripheral Neuropathic Pain (CIPNP). CIPNP is one of the primary reasons a patient receives a limited dose of taxane. No diagnostic tool exists to identify patients that will develop CIPNP in response to taxane therapy. Biomarker signatures associated with taxane-induced neuropathic pain will be developed to: 1) identify patients at risk for developing debilitating taxane neuropathic pain before chemotherapy is initiated; and 2) to identify patients already on treatment who are at risk of developing neuropathic pain and need dosing adjustments to prevent CIPNP symptoms. This biomarker signature will be used to detect CIPNP-susceptible patients early and personalize their taxane therapy to minimize CIPNP while optimizing the therapeutic taxane dosing.

Overreliance on opioids to treat chronic pain has been a contributor to the increase in individuals experiencing opioid addiction. This project aims to develop an innovative treatment approach for chronic pain that targets the cannabinoid receptor 1 (CB1R) to block the sensation of pain. The approach seeks to identify molecules that interact with a different part of the CBR1 receptor than do endocannabinoids and the primary active component of cannabis, tetrahydrocannabinol. Molecules that bind to and activate CBR1 in this different way (at an “allosteric” site) may produce nerve signaling that might differ from the effects of cannabis and endocannabinoids. This redirection of signaling pathways could help eliminate the risk of adverse effects observed with natural cannabinoids and other CBR1-binding molecules. The goal of this project is to identify a CB1R allosteric molecule, conduct studies toward obtaining federal permission to develop it as a medication, and to test it in a Phase I clinical study.

Efforts to identify non-opioid analgesics for treatment of chronic pain have identified a protein, carbonic anhydrase-8 (CA8), in pain-sensing nerve cells in the spinal cord (dorsal root ganglion cells) whose expression regulates analgesic responses. Gene therapy delivering CA8 to dorsal root ganglion cells through clinically relevant routes of administration functions as a “local anesthetic” that induces long-lasting pain relief in animal models of chronic pain. This project will further develop CA8 gene therapy with the goal of treating chronic knee osteoarthritis pain. It will assess several gene therapy constructs to determine the doses needed, safety, efficacy, and specificity to nerve cells for each construct. It will then select the safest and most effective construct that can be administered via the least invasive route for further development. The project will include all steps necessary to identify one candidate gene therapy construct that will be suitable to begin clinical trials in patients with chronic knee osteoarthritis pain.

Researchers will develop an innovative three-dimensional (3D) model of acute and chronic nociception using human induced pluripotent stem cell (hiPSC) sensory neurons and satellite glial cell surrogates. They will develop a tissue chip for modeling acute and chronic nociception based on 3D hiPSC-based dorsal root ganglion tissue mimics and a high-content, moderate-throughput microelectrode array. Researchers will demonstrate stable spontaneous and noxious stimulus-evoked behavior in response to thermal, chemical, and electrical stimulation challenges. They aim to demonstrate sensitivity to translational control via ligand receptor interactions between neuronal and non-neuronal cell types. They also will demonstrate the quantitative efficiency and preclinical efficacy of our system by detecting known ligand-based modulators of translational control and voltage-gated ion channel antagonists in a sensitized model of chronic nociception. Researchers will leverage the high-throughput nature of our tissue chip model to screen Food and Drug Administration–approved bioactive compounds.

Voltage-gated sodium channels such as Nav1.7, Nav1.8, and Nav1.9 transmit pain signals in nerve fibers and are molecular targets for pain therapy. While Nav channels have been validated as pharmacological targets for the treatment of pain, available therapies are limited due to incomplete efficacy and significant side effects. Taking advantage of recent advances in structural biology and computational-based protein design, this project aims to develop antibodies to attach to Nav channels and freeze them in an inactive state. These antibodies can then be further developed as novel treatments for chronic pain.

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.