Funded Projects

Multi-protein complexes have emerged as a mechanism for spatiotemporal specificity and efficiency in the function and regulation of myriad cellular signals. In particular, many ion channels are clustered either with the receptors that modulate them, or with other ion channels whose activities are linked. Often the clustering is mediated by scaffolding proteins, such as the AKAP79/150 protein that is a focus of this research. This research will focus on three different channels critical to nervous function. One is the"M-type" (KCNQ, Kv7) K+ channel that plays fundamental roles in the regulation of excitability in nerve and muscle. It is thought to associate with Gq/11- coupled receptors, protein kinases, calcineurin (CaN), calmodulin (CaM) and phosphoinositides via AKAP79/150. Another channel of focus is TRPV1, a nociceptive channel in sensory neurons that is also thought to be regulated by signaling proteins recruited by AKAP79/150. The third are L-type Ca2+ (CaV1.2) channels that are critical to synaptic plasticity, gene regulation and neuronal firing. This research will probe complexes containing AKAP79/150 and these three channels using"super-resolution" STORM imaging of primary sensory neurons and heterologously-expressed tissue-culture cells, in which individual complexes can be visualized at 10-20 nm resolution with visible light, breaking the diffraction barrier of physics. The researchers hypothesize that AKAP79/150 brings several of these channels together to enable functional coupling, which the researchers will examine by patch-clamp electrophysiology of the neurons. Förster resonance energy transfer (FRET) will also be performed under total internal reflection fluorescence (TIRF) or confocal microscopy, further testing for complexes containing KCNQ, TRPV1 and CaV1.2 channels. Since all three of these channels bind to AKAP79/150, the researchers hypothesize that they co-assemble into complexes in neurons, together with certain G protein-coupled receptors. Furthermore, the researchers hypothesize these complexes to not be static, but rather to be dynamically regulated by other cellular signals, which the researchers will examine using rapid activation of kinases or phosphatases. Several types of mouse colonies of genetically altered AKAP150 knock-out or knock-in mice will be utilized.

Neuropathic corneal pain (NCP) causes patients to have severe discomfort and a compromised quality of life (QoL). The lack of signs observed by standard examination has resulted in misdiagnosis as dry eye disease (DED). An optical biopsy using laser in vivo confocal microscopy (IVCM) revealed that microneuromas (bulbs at the ends of severed nerves caused by buildup of molecular constituents) are present in NCP but not DED and may serve as a biomarker for NCP. The aims are to (1) use a database of more than 2,000 DED/NCP subjects and more than 500,000 IVCM images to confirm that the presence of microneuromas is an appropriate biomarker for NCP, (2) provide biological validation of microneuromas, (3) develop a validated artificial intelligence (AI) program for automated identification of microneuromas, and (4) establish the clinical utility of microneuromas observed by IVCM as a biomarker for NCP in a prospective, multicenter study.

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.

The development of non-addictive pain therapeutics can help counter opioid addiction and benefit patients, including those who suffer from neuropathic pain, in particular diabetic neuropathic pain (DNP). This project’s goal is to develop a safe, efficacious, and non-addictive small-molecule drug that activates Kv7 voltage-gated potassium channels to address overactive neuronal activity in DNP. Researchers will discover Kv7 activators that favor Kv7 isoforms altered in DNP and found in dorsal root ganglia, decrease off-target side effects observed with the use of earlier non-biased Kv7 activators, and optimize the absorption, distribution, metabolism, excretion, and toxicity profiles of these activators. This screening paradigm is intended to establish a clinic-ready, well-tolerated, and widely effective product to treat neuropathic pain.

Persistent pain states arising from inflammatory conditions, such as in arthritis, diabetes, HIV, and chemotherapy, exhibit a common feature in the release of damage-associated molecular pattern molecules, which can activate toll-like receptor-4 (TLR4). Previous studies suggest that TLR4 is critical in mediating the transition from acute to persistent pain. TLR4 as well as other inflammatory receptors localize to lipid raft microdomains on the plasma membrane. We have found that the secreted apoA-I binding protein (AIBP) accelerates cholesterol removal, disrupts lipid rafts, prevents TLR4 dimerization, and inhibits microglia inflammatory responses. We propose that AIBP targets cholesterol removal to lipid rafts harboring activated TLR4. The aims of this proposal are to: 1) determine whether AIBP targets lipid rafts harboring activated TLR4; 2) test whether AIBP reduces glial activation and neuroinflammation in mouse models of neuropathic pain; and 3) identify the origin and function of endogenous AIBP in the spinal cord.

There is currently no recognized way of accurately predicting who will recover from post-traumatic headache (PTH) during the acute phase following concussion and who will go on to develop persistent post-traumatic headache (PPTH), a condition that is difficult to treat effectively. Clinical experience suggests that early treatment is most effective, before headache patterns become persistent, but treating all patients with PTH would expose some patients to unnecessary treatment. Clinicians lack the information needed to make informed treatment decisions. Therefore, the study goals are to develop a prognostic biomarker signature for PPTH using clinical data and structural and functional brain neuroimaging and to assess the predictive accuracy of an ensemble biomarker signature for the early identification of patients at high risk for PPTH. This study can be translated into clinical practice and integrated into PTH clinical trials for early identification of those individuals who are at high risk for PPTH.

This project will develop a human cell-based model of the afferent pain pathway in the dorsal horn of the spinal cord. The research team’s approach utilizes novel human pluripotent stem cell (hPSC)-derived phenotypes in a model that combines 3D organoid culture with microfabricated systems on an integrated, three-dimensional (3D) microelectrode array. Researchers will establish the feasibility of a physiologically relevant, human 3D model of the afferent pain pathway that will be useful for evaluation of candidate analgesic drugs. They will then improve the physiological relevance of the system by promoting neural network maturation before demonstrating the system’s utility in modeling adverse effects of opioids and screening compounds to validate the model. Completion of the study objective will establish novel protocols for deriving dorsal horn neurons from hPSCs and create the first human microphysiological model of the spinal cord dorsal horn afferent sensory pathway.

We propose to develop a safe and effective nonopioid analgesic to treat neuropathic pain that targets an isoform of the voltage-gated sodium ion channel, NaV1.7. Voltage-gated sodium channels are involved in the transmission of nociceptive signals from their site of origin in the peripheral terminals of DRG neurons to the synaptic terminals in the dorsal horn. NaV1.7 is the most abundant tetrodotoxin-sensitive sodium channel in small diameter myelinated and unmyelinated afferents, where it has been shown to modulate excitability and set the threshold for action potentials. Development of systemic NaV1.7 inhibitors has been complicated by the challenge of achieving selectivity over other NaV isoforms expressed throughout the body. We have discovered a series of potent, state-independent NaV1.7 inhibitors that exhibit >1000-fold selectivity over other human isoforms. Work conducted under this program will support advancement of a lead candidate into clinical development as a therapeutic 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.

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.

Currently, there are no adequate therapies for abdominal pain in patients with Irritable Bowel Syndrome (IBS), a gastrointestinal disorder affecting 14-20% of the US population. More than 40% of IBS patients regularly use opioid narcotics. An alternative treatment for IBS that has been shown to be an effective pain management strategy is electroacupuncture. However its drawbacks include infrequent administration, unclear mechanistic understanding, and lack of methodology optimization. This study will use a noninvasive method of transcutaneous electrical acustimulation (TEA) by replacing needles with surface electrodes and testing acupoints that target peripheral nerves. Based on prior mechanistic and clinical studies, two stimulation parameters and effective acupoints will be tested. In the UG3 phase, the TEA device and a cell phone app will be optimized for use in IBS abdominal pain, and an acute clinical study will determine the best stimulation locations and parameters. During the UH3 phase, an early feasibility clinical study will be performed in 160 IBS patients in treating abdominal pain. Participants will self-administer the therapy at home/work and will be randomized across four treatment groups to determine the therapeutic potential of the TEA system.

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.

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.