Funded Projects

Neuropathic pain conditions are difficult to treat, and novel non-narcotic analgesics are desperately needed. The G protein-coupled receptor 160 (GPR160) has emerged as a novel target for analgesic development, as GPR160 in the spinal cord may play a role in the transition from acute to chronic pain. Cocaine- and Amphetamine-Regulated transcript peptide (CARTp) was identified as a ligand for GPR160. Blocking endogenous CARTp signaling in the spinal cord attenuates neuropathic pain, whereas intrathecal injection of CARTp evokes painful hypersensitivity in rodents through GPR160-dependent extracellular signal-regulated kinase (ERK) and cyclic AMP response element-binding pathways (CREB). This project will isolate and biochemically characterize GPR160 and establish methods for biochemical characterization of GPR160 interaction with CARTp activator. Researchers will miniaturize and optimize biochemical assay and scale up protein production for future high throughput biochemical screening to identify potent inhibitors of GPR160 activation. These studies are critical for defining the molecular mechanism of CARTp/GPR160 interactions and initiating large-scale screens for new inhibitors to develop novel therapeutics.

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.

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.

This project will use a variety of technologies to create a comprehensive, 3D map of how sensory neurons activate knee joints in both mice and humans. The research will use imaging techniques and molecular approaches that measure gene expression. The findings will help create a comprehensive gene expression profile map of individual cells in the nerve fibers leading to the knee, as well as describe how nerve cells and joint cells interact at the most fundamental level. This research will generate a rich anatomical and molecular resource to understand the molecular basis of joint pain and guide the development of novel pain-relieving strategies.

Technology approaches that deliver electrical current through the skin near a damaged or injured peripheral nerve are used to treat chronic neuropathic pain that does not respond to other treatments. This project will optimize this nerve stimulation approach while also determining how the stimulation works to reduce pain in the body. The research will also look for patient characteristics that predict response by conducting a clinical trial comparing combined peripheral nerve stimulation and conventional medical treatment to medication alone.

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.

This project will build overdose models for fentanyl, methadone, codeine, and morphine in a multi-organ system and evaluate the acute and repeat dose, or chronic effects, of overdose treatments as well as off-target toxicity. Researchers developed a system using human cells in a pumpless multi-organ platform that allows continuous recirculation of a blood surrogate for up to 28 days. They will develop two overdose models for male and female phenotypes based on pre-B?tzinger Complex neurons and will integrate functional immune components that enable organ-specific or systemic monocyte actuation. Models for cardiomyopathy and infection will be utilized. Researchers will establish a pharmacokinetic/pharmacodynamic model of overdose and treatment to enable prediction for a range of variables. We will use a serum-free medium with microelectrode arrays and cantilever systems integrated on chip that allow noninvasive electronic and mechanical readouts of organ function.

The research team will develop stimulation control algorithms to treat chronic pain using a novel device that allows longitudinal intracranial signal recording in an ambulatory setting. Subjects with refractory chronic pain syndromes will undergo bilateral surgical implant of temporary electrodes in the thalamus, anterior cingulate, prefrontal cortex, insula, and amygdala to identify candidate biomarkers of pain and optimal stimulation parameters. Six patients will proceed to chronic implantation of “optimal” brain regions for long-term recording and stimulation. The team will first validate biomarkers of low- and high-pain states to define neural signals for pain prediction in individuals. They will then use these pain biomarkers to develop personalized closed-loop algorithms for deep-brain stimulation (DBS) and test the feasibility of closed-loop DBS for chronic pain in weekly blocks. Researchers will assess the efficacy of closed-loop DBS algorithms against traditional open-loop DBS or sham in a double-blinded cross-over trial and measure mechanisms of DBS tolerance.

Pain caused by degenerative joint diseases such as osteoarthritis (OA) is a major public health challenge that significantly affects quality of life for millions of Americans. There are no therapies available that offer pain relief and reverse the course of OA.  This project will use state-of-the-art technologies to create a neuronal connectivity and molecular map of the mouse knee joint, which will help identify molecular signatures that can be targeted for therapy. The research will include animals of different ages and of both sexes and test joint effects after exercise, in animals with OA, and after gene therapy that delivers an experimental OA medication directly to the joint.

High-voltage-gated calcium channels convert electrical signals into physiological responses. After a nerve injury, levels of these channels go down in some neurons in the dorsal root ganglia that communicates pain signals to and from the brain. This decline results in reduced flow of calcium that may underlie pain. This project will develop novel approaches to block these calcium channels p to further study their roles in controlling pain.

Approximately 3.6 million Americans live with an amputated extremity, and the majority of these individuals are likely to suffer from chronic post-amputation pain. There is no consensus as to a recommended therapy for such pain, and many treatments do not provide sufficient pain control. Some studies have shown effective pain suppression from delivering an anesthetic agent directly to an injured nerve. This research aims to develop a device that can be implanted near the injured nerves of an amputated limb to deliver an anesthetic. Findings from this preclinical study will optimize design and delivery features to maximize its effect on pain control for as long as possible without needing a drug refill. The research is expected to advance eligibility for further testing in large animals and humans.

An extensive literature provides compelling evidence that selective antagonists or negative allosteric modulators (NAMs) of the metabotropic glutamate (mGlu) receptor, mGlu5, have exciting potential as a novel approach for treatment of multiple pain conditions that could provide sustained antinociceptive activity without the serious adverse effects and abuse liability associated with opioids. Researchers have developed a novel series of highly selective mGlu5 NAMs that are structurally unrelated to previous compounds, have properties for further development, and avoid the formation of toxic metabolites that were associated with previous mGlu5 NAMs. Based on existing preclinical models, as well as clinical trial data showing efficacy of an mGlu5 NAM in migraine patients, researchers anticipate that their compounds will have broad-spectrum analgesic activity in patients with a variety of chronic pain conditions.

An International Cooperative Biodiversity Group with an interdisciplinary leadership team of physicians, pharmacologists, evolutionary biologists, and chemists will discover and develop therapeutic agents produced by Brazilian symbiotic bacteria. The team will target three therapeutic areas: 1) infectious fungal pathogens, 2) Chagas disease and leishmaniasis, and 3) cancers of the blood. All three areas represent major threats to human health that need to be addressed with new therapeutic agents. Internationally, invasive fungal diseases kill more people than malaria or TB, while Chagas disease imposes a special burden on Brazil, killing as many Brazilians as TB. Leishmaniasis has now passed Chagas disease in the Brazilian population. Despite major improvements in cancer chemotherapy, cancer is projected to result in 8 million deaths internationally this year (13% of all deaths, WHO) and an estimated 13 million per year by 2030.