Funded Projects

Data suggest that members of minority groups are more likely to develop chronic pain and to have greater pain burden. We will identify a set of promising intervention targets for reducing or eliminating racial/ethnic pain disparities. We will interview adult survivors of serious physical injury, comprised of roughly equal proportions of African-Americans (AA), Latinos, and non-Latino Whites (NLW), and examine their medical records for information on injury severity and medication use in-hospital. Our aims are to determine whether: 1) AA and Latino physical injury survivors experience more severe pain relative to NLW; 2) AA and Latino injury survivors experience greater pain burden relative to NLW counterparts; 3) differences in pain severity burden are linked to a set of target candidates for interventions; and (4) pain outcomes in at-risk minority groups can be linked to a set of target candidates for group-tailored interventions to reduce pain severity and pain burden.

The research team will develop an implantable neural stimulation system to provide natural and intuitive sensation for prosthesis users. The nerve cuff technology meets the requirements for a sensory feedback system capable of providing consistent and controlled electrical stimulation. Coupled with a multichannel implantable stimulator, this electrode array will offer substantial improvement over existing options to treat phantom limb pain (PLP). In Phase I, researchers will finalize array architectures for evaluation in cadaver studies, complete integration of electrodes with our stimulator, conduct benchtop verification of electrical and mechanical performance, send implants for third-party evaluation of system biocompatibility, and complete a Good Laboratory Practice animal study to validate safety and efficacy. In Phase II, researchers will conduct a 5-subject clinical study to test the implantable stimulation system. Each unilateral prosthesis user will be implanted for one year as researchers evaluate the safety and efficacy of this implantable device to treat PLP.

The research team will develop HD64—a high-resolution, 64-channel spinal cord stimulation therapy to provide more pain relief for those suffering from chronic neuropathic pain and opioid dependence. HD64 provides an ultra-thin conformal blanket of stimulation contacts across the width of the spinal cord and enables more precise targeting of the lateral structures of the spinal cord to enhance pain relief. A cadaveric pilot run followed by a non-significant risk intraoperative study will be performed to inform the design parameters of HD64 arrays. The study will evaluate activation of medial and lateral spinal targets. At the end of Phase 1, the clinical feasibility of HD64 surgical leads will be established. In Phase 2, researchers will develop an external active lead pulse generator and charger. They will perform an early feasibility study human trial using active HD64 and mechanical and electrical design verification testing and chronic safety studies in large animals.

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.

Chemotherapy-induced painful peripheral neuropathy (CIPN) is the most common toxicity associated with widely used chemotherapeutics. CIPN accounts for significant dose reductions and/or discontinuation of these life-saving treatments. Unfortunately CIPN can also persist in cancer-survivors, adversely affecting their quality of life. CIPN is not well-managed with existing pain therapeutics. Recent preliminary findings suggest that the transcription factor hypoxia-inducible factor alpha (HIF1A) is the target for the chemotherapeutic bortezomib, a proteasome inhibitor. This project will test the hypothesis that bortezomib chemotherapy-induced expression of HIF1A, PDHK1 and LDHA constitute an altered metabolic state known as aerobic glycolysis (AG) that leads to the initiation and maintenance of peripheral neuropathy and pain using a novel tumor-bearing animal model of CIPN. This project aims to validate HIF1A as a therapeutic target for the prevention of CIPN, as well as validate PDHK1 and LDHA as non-opioid therapeutic targets for chronic or established CIPN in animal models.

Neuropathic pain is a debilitating affliction present in 26% of diabetic patients, with substantial impact on the quality of life. Despite this significant impact and prevalence, current therapies for painful diabetic neuropathy (PDN) are only partially effective, and the molecular mechanisms underlying neuropathic pain in diabetes are not well understood. Our long-term goal is to elucidate the molecular mechanisms responsible for PDN in order to provide targets for the development of therapeutic agents. Our objective is to identify the molecular cascade linking CXCR4/SDF-1 chemokine signaling to DRG nociceptor hyper-excitability, neuropathic pain, and small fiber degeneration. Our aims will determine: 1) the ion-channel current profile of the nociceptor hyper-excitable state produced by CXCR4/SDF-1 signaling in PDN; 2) the gene expression profile of the nociceptor hyper-excitable state produced by CXCR4/SDF-1 signaling in PDN; and 3) the specific features of nociceptor mitochondrial dysfunction produced by CXCR4/SDF-1 signaling in PDN.

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.

To avoid the reliance on opioids for treatment of pain, researchers are investigating alternative approaches to disrupt the transmission of pain signals by specialized neurons in the body, such as dorsal root ganglion neurons in the spinal cord. Molecules called voltage-gated sodium channels that are located in the membranes of dorsal root ganglion neurons are essential for transmission of the pain signals. People carrying a specific variant of these channels, NaV1.7, are insensitive to pain; therefore, strategies to block this particular channel might help in the development of non-addictive pain treatment approaches. Navega Therapeutics is developing an innovative gene therapy that specifically targets NaV1.7. Using studies in human cell lines, they will identify the best designs to then test this gene therapy approach in human dorsal root ganglion neurons.

Mindfulness has been shown to be effective in treating chronic low back pain, but it has not been embedded into routine clinical care. The OPTIMUM study (Optimizing Pain Treatment In Medical settings Using Mindfulness) will address barriers to delivering mindfulness in primary care and determine the effectiveness in this setting. This project extends the stakeholder engagement efforts of the OPTIMUM study by increasing the size and responsibilities of the Community Advisory Board, adding focus groups for participants in both study arms, and collecting stories from study nonparticipants about their experience seeking care for chronic low back pain and their views on participating in research. This expanded effort will optimize recruitment of a diverse and underrepresented sample, maximize retention, and prepare for future implementation and dissemination.

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.

The need to develop non-opioid therapeutics for chronic pain is greater than ever.  One option being explored is inhibiting the activity of calpains – enzymes that have been shown to cause pain in animal models of chronic pain.  Using an artificial intelligence (AI)-driven drug discovery platform, researchers have uncovered and validated four calpain-1 inhibitors using biochemical assays.  This study by 1910 Genetics Inc. hopes to synthesize multiple analogs of its most potent discovered calpain-1 inhibitor and determine its effectiveness against calpain-2 and certain enzymes that break down proteins.  Findings that successfully significantly inhibit calpain-1 in at least one animal model of chronic pain could lead to the first oral, central nervous system penetrating selective calpain-1 inhibitor [non-opioid therapeutic] for chronic pain.

It is unclear what changes in the brain mediate the development of chronic pain from acute pain and how chronic pain may change responses to opioid reward for the altered liability of opioid abuse under chronic pain. Preliminary studies have found that Dnmt3a, a DNA methyltransferase that catalyzes DNA methylation for gene repression, is significantly downregulated in the brain in a time-dependent manner during the development of chronic pain and after repeated opioid treatment. This project will investigate whether Dnmt3a acts as a key protein in the brain for the development of chronic pain, and whether Dnmt3a could be a novel epigenetic target for the development of new drugs and therapeutic options for the treatment of chronic pain while decreasing abuse liability of opioids.

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.