Funded Projects

Genomic medicine offers hope for improved diagnostic methods and for more effective, patient-specific therapies. Genome-wide associated studies (GWAS) elucidate genetic markers that improve clinical understanding of risks and mechanisms for many diseases and conditions and that may ultimately guide diagnosis and therapy on a patient-specific basis. Previous phenome-wide association studies (PheWAS) established a systematic and efficient approach to identifying novel disease-variant associations and discovering pleiotropy using electronic health records (EHRs). This proposal will develop novel methods to identify associations based on patterns of phenotypes using a phenotype risk score (PheRS) methodology to systematically search for the influence of Mendelian disease variants on common disease. By doing so, it also creates a way to assess pathogenicity for rare variants and will identify patients at highest risk of having undiagnosed Mendelian disease. The project is enabled by large DNA biobanks coupled to de-identified copies of EHR.

Despite the need for non-opioid treatments for chronic pain, few alternative treatment approaches exist. Transcutaneous auricular neurostimulation (tAN) is a safe and effective treatment for pain during opioid withdrawal; however, researchers do not understand how tAN reduces pain, which limits its clinical use. A better understanding of how tAN affects neurophysiological processes to provide pain relief would likely expand tAN development and use. This interdisciplinary project will conduct research in both healthy adults and those with chronic pain to explain the neurochemical and neurophysiological mechanisms for tAN-based pain relief, and also help optimize treatments and their use.

Spinal cord injury (SCI) impairs sensory transmission leading to chronic, debilitating neuropathic pain. While our understanding of the molecular basis underlying the development of chronic pain has improved, the available therapeutics provide limited relief. In the lab, we have shown the timing of exercise is critical to meaningful sensory recovery. Early administration of a sustained locomotor exercise program in spinal cord–injured rats prevents the development of neuropathic pain, while delaying similar locomotor training until pain was established was ineffective at ameliorating it. The time elapsed since the injury occurred also indicates the degree of inflammation in the dorsal horn. We have previously shown that chronic SCI and the development of neuropathic pain correspond with robust increases in microglial activation and the levels of pro-inflammatory cytokines. This proposal seeks to lengthen the therapeutic window where rehabilitative exercise can successfully suppress neuropathic pain by pharmacologically reducing inflammation in dorsal root ganglia.

Neck pain is the fourth leading cause of disability and also a significant cause of cervicogenic headaches. Many of the currently available neck pain treatments are invasive with associated risks and complications, particularly because of the complex anatomy. Magnetic resonance guided focused ultrasound, a novel, completely noninvasive technique, can precisely target spinal facet joints to help ameliorate neck pain, potentially transforming the current practices. The goal of this study is to develop a cervical spine-specific device and demonstrate its safety and efficacy on targeting cervical sensory fibers and the third occipital nerve. The results of these studies will provide an understanding on how to best use this technology for chronic neck pain as well as a basis for translation into human use.

Opioids are widely used pain treatments, despite their relative ineffectiveness for chronic pain and their high potential for misuse and addiction. There is thus an urgent need for alternative, non-addictive pain treatments. Genetic and functional studies of human pain disorders and animal models of pain have validated Nav1.7, a voltage-gated sodium channel as an attractive target for new pain treatments. Currently available blockers of these channels can sometimes provide symptomatic relief for patients but have worrisome side effects affecting the brain and heart. This study aims to develop and validate an innovative site-directed RNA editing strategy that will offer the ability to create new versions of molecules to block Nav1.7, toward establishing a novel, non-addictive approach to treat chronic pain.

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.

Pain signals originate predominantly in a subset of peripheral sensory neurons that harbor a distinct subset of voltage-gated sodium (NaV) channels; however, current NaV channel blockers, such as local anesthetics, are non-selective and also block NaV channels vital for function of the heart, muscle, and central nervous system. Genetic studies have identified human NaV1.7, NaV1.8, and NaV1.9 channel subtypes as key players in pain signaling and as major contributors to action potential generation in peripheral neurons. ProTx-II is a highly potent and moderately selective peptide toxin that inhibits human NaV1.7 activation. This study will optimize ProTx-II selectivity, potency, and stability by exploiting the new structures of ProTx-II—human NaV1.7 channel complexes, advances in rational peptide optimization, and rigorous potency and efficacy screens to generate high-affinity, selective inhibitors of human NaV1.7, NaV1.8, and NaV1.9 channels that can define a new class of biologics to treat pain.

An important component of neuropathic pain is spontaneous or ongoing pain, such as burning pain or intermittent paroxysms of sharp and shooting pain, which may result from abnormal spontaneous activity in sensory nerves. However, due to technical limitations, spontaneous activity in sensory neurons in vivo has not been well studied. Using in vivo imaging in genetically-modified mice, preliminary findings identified spontaneously-firing clusters of neurons formed within the dorsal root ganglia (DRG) after traumatic nerve injury that exhibits increased spontaneous pain behaviors. Furthermore, preliminary evidence has been collected that cluster firing may be related to abnormal sympathetic sprouting in the sensory ganglia. This project will test the hypothesis that cluster firing is triggered by abnormal sympathetic inputs to sensory neurons, and that it underpins spontaneous paroxysmal pain in neuropathic pain models. Findings from this project will identify potential novel therapeutic targets for the treatment of neuropathic pain.

Natural products, which are substances found in nature and made by living organisms, have been used in the past as good sources for developing new medications. Natural products isolated from marine bacteria that attach to the pain-signaling protein sigma-2 receptor (also known as transmembrane protein 97 [TMEM97]), may serve as a starting point to create new, non-opioid pain medications. This project will use chemistry and biology approaches to refine such natural products as a treatment for neuropathic pain.

Migraine is a painful and debilitating neurological condition, the development and maintenance of which involves the neuropeptide calcitonin gene-related peptide (CGRP). An exciting development in the treatment of migraine is the recent FDA approval of a new class of CGRP-targeted therapies designed to prevent migraine. However, these drugs meet a clinically relevant endpoint for only about half of the patients. This project will test the hypothesis that the high-affinity CGRP receptor AMY1 is a novel and unexplored target that mediates specific migraine-related behaviors in the brain and/or periphery to cause migraine. Validation of CGRP and AMY1 receptor involvement in migraines will create a new direction for the development of novel drugs and provide alternatives to opioids for management of migraine and potentially for other chronic pain conditions.

This study aims to address critical gaps and unmet therapeutic needs of chronic low back pain (CLBP) patients using a next-generation deep brain stimulation (DBS) device with directional steering capability to engage networks known to mediate the affective component of CLBP. Researchers will utilize patient-specific probabilistic tractography to target the subgenual cingulate cortex (SCC) to engage the major fiber pathways mediating the affective component of chronic pain. The objective is to conduct an exploratory first-in-human clinical trial of SCC DBS for treatment of medically refractory CLBP. The research team aims to: (1) assess the preliminary efficacy of DBS of SCC in treatment of medically refractory CLBP; (2) demonstrate the safety and feasibility of SCC DBS for CLBP; and (3) develop diffusion tensor imaging–based blueprints of response to SCC DBS for CLBP.

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.