Funded Projects

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.

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.

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.

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.

Epidural/spinal administration of analgesics such as opioids, ziconotide and local anesthetics have profound efficacy in some of the most intractable pain conditions such as severe neuropathic pain after failed back surgery, cancer pain and post-operative pain after major abdominal/thoracic surgeries. Contulakin G (CGX) is a snail venom derived peptide that has homology with mammalian neurotensin and was shown to be safe in humans in preliminary studies. A small pilot study demonstrated CGX?s analgesic effect in some patients with spinal cord injury-associated pain. Preliminary findings from mechanistic studies in rodents identified neurotensin receptor 2 (NTSR2) as the mediator for analgesic effects of CGX. This project aims to validate spinal NTSR2 as an analgesic target utilizing three species (rat, mice and human), and two pain models (neuropathic pain and post-surgical pain). The project will utilize pharmacological and gene editing tools such as CRISPR-Cas9 and will include assessment of both sensory and affective measures of pain. A two-site parallel confirmation study is designed based on multisite clinical trials to further authenticate spinal NTSR2 as an analgesic target. Successful completion of this project could lead to the development of a non-opioid spinal analgesic that has high translational potential.

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.

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.

Researchers will develop multi-organ, microphysiological systems (MPSs) based on human induced pluripotent stem cell-derived midbrain-fated dopamine (DA)/gamma-aminobutyric acid neurons on a three-dimensional platform that incorporates microglia, blood–brain barrier (BBB), and liver metabolism. RNA sequencing and metabolomics analyses will complement the primary DA release measure to identify novel mechanisms contributing to chronic opioid-induced plasticity in DA responsiveness. The chronic pain-relevant aspect of the model will be realized by examination of aversive kappa-mediated opioid effects on DA transmission in addition to commonly abused mu opioid receptor agonists, and by incorporation of inflammatory-mediating microglia. Incorporation of BBB and liver metabolism modules into the microphysiologic system platform will permit screening of drugs. Throughput will be increased by integration of online sensors for online detection of DA and other analytes. Researchers will use a curated set of 100 chemical genomics probes.

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.

The goal of this project is to generate data and reagents that help uncover critical functions of the poorly characterized members of ion channels. It focuses on co-perturbation of ion channel genes and their interacting genetic components as opposed to singly altering ion channel genes in mouse models. This approach will validate our proteomics approaches in the most definitive manner: in vivo. We see in vivo exploration as an essential step to evaluate ion channel function. Our major aims include mapping ion channel interactions and complexes using a high-throughput proteomics platform at UCSF. These data will be interrogated using integrative approaches established by the Monarch Initiative, where biochemical interactions will be validated and prioritized for further study. Another major aim is function-centric: We use mouse models for elucidation of human disease mechanisms, where we embrace a genetic interaction scheme to uncover ion channel redundancy and polygenic effects.

Validation of novel pain targets is a critical step toward the development of new non-addictive therapeutic agents for chronic pain management. Recent findings suggest that nerve injury-induced concurrent upregulation of the calcium channel alpha-2delta-1 subunit (CaValpha-2-delta-1) and thrombospondin-4 (TSP4) proteins in sensory and spinal cord neurons contributes to neuropathic pain development. Specifically, induction of aberrant excitatory synapse formation and sensitization of neurotransmission in spinal cord underlies this process; accordingly, a target site has been identified in the TSP4 that plays a critical role in mediating these pathological changes upon interaction with the CaValpha-2-delta-1 protein. This project will validate this novel target site in TSP4 for development of non-addictive pain medications, utilizing multidisciplinary approaches to investigate if blocking and genetic deletion of the target site can block or prevent the development of chronic pain state, aberrant excitatory synapse formation, and spinal cord neuron sensitization after injury in multiple rodent neuropathic pain models.

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.