Chronic orofacial pain is a common clinical syndrome lacking specific and effective therapeutic agents due to the fact that cellular mechanisms of chronic orofacial pain are poorly understood. Based on our preliminary data from a trigeminal nerve injury model and in non-orofacial pain models, we hypothesize that trigeminal nerve injury induced thrombospondin-4 (TSP4) expression in trigeminal ganglia (TG) and associated brainstem/upper cervical spinal cord (Vc/C2) that causes sensory neuron hyperexcitability, and abnormal synaptogenesis in the trigeminal complex in the spinal cord. These changes underlie the transition from trigeminal nerve injury to chronic pain development. In this proposal, we plan to identify the critical domain(s) of TSP4 in mediating behavioral hypersensitivity and spinal neuron hyperexcitability. Viral driven TSP4 expression in TG or Vc/C2, respectively, will be used to identify the site of the TSP4's action in chronic pain processing. We will perform confocal and electron microscopy to determine the extent of abnormal synaptogenesis in the nerve injury models. In addition, the influence of descending modulatory pathways and voltage-gated-calcium channels on TSP4-mediated behavioral hypersensitivity and dorsal horn neuron hyperexcitability will be studies using respective drugs. The influence of TSP4 on sensory neuron excitability, calcium channel activities, and intracellular calcium signaling will be studied in isolated neurons or intact TG from nerve injury models, or after TSP4 treatment. To determine if TSP4 induces behavioral hypersensitivity and dorsal horn neuron hyperexcitability through its interactions with its receptor, the calcium channel alpha-2-delta-1 subunit (Cava2d1), in a sensory neuron specific manner, Cava2d1 conditional knockout mice with selective deletion of Cava2d1 in subpopulation of sensory neurons will be used for these studies. The final goal of the proposed studies is to identify the peripheral and/or central mechanisms underlying TSP4-mediated transition to chronic pain states after trigeminal nerve injury.

Public Health Relevance

Chronic orofacial neuropathic pain often evolves from a preceding injury of the peripheral nerves, which is accompanied by initial nociceptive pain. Identification of the mechanisms underlying this transition would be critically valuable in preventing or reversing it. We plan to study a novel pathway mediated by injury-induced expression of thrombospondin 4 in mediating orofacial neuropathic pain. Completion of this study will provide important information for identifying a novel mediator for the transition to chronic orofacial pain after nerve injury.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
5R01DE021847-04
Application #
8617090
Study Section
Special Emphasis Panel (ZDE1-VH (02))
Program Officer
Kusiak, John W
Project Start
2011-04-07
Project End
2016-02-29
Budget Start
2014-03-01
Budget End
2015-02-28
Support Year
4
Fiscal Year
2014
Total Cost
$722,774
Indirect Cost
$179,616
Name
University of California Irvine
Department
Anesthesiology
Type
Schools of Medicine
DUNS #
046705849
City
Irvine
State
CA
Country
United States
Zip Code
92697
Yu, Yanhui Peter; Gong, Nian; Kweon, Tae Dong et al. (2018) Gabapentin prevents synaptogenesis between sensory and spinal cord neurons induced by thrombospondin-4 acting on pre-synaptic Cav ?2 ?1 subunits and involving T-type Ca2+ channels. Br J Pharmacol 175:2348-2361
Park, John Francisco; Yu, Yanhui Peter; Gong, Nian et al. (2018) The EGF-LIKE domain of thrombospondin-4 is a key determinant in the development of pain states due to increased excitatory synaptogenesis. J Biol Chem 293:16453-16463
Gong, Nian; Park, John; Luo, Z David (2018) Injury-induced maladaptation and dysregulation of calcium channel ?2 ? subunit proteins and its contribution to neuropathic pain development. Br J Pharmacol 175:2231-2243
Guo, Yuan; Zhang, Zhiyong; Wu, Hsiang-En et al. (2017) Increased thrombospondin-4 after nerve injury mediates disruption of intracellular calcium signaling in primary sensory neurons. Neuropharmacology 117:292-304
Park, John; Yu, Yanhui Peter; Zhou, Chun-Yi et al. (2016) Central Mechanisms Mediating Thrombospondin-4-induced Pain States. J Biol Chem 291:13335-48
Park, John; Trinh, Van Nancy; Sears-Kraxberger, Ilse et al. (2016) Synaptic ultrastructure changes in trigeminocervical complex posttrigeminal nerve injury. J Comp Neurol 524:309-22
Pan, Bin; Guo, Yuan; Wu, Hsiang-En et al. (2016) Thrombospondin-4 divergently regulates voltage-gated Ca2+ channel subtypes in sensory neurons after nerve injury. Pain 157:2068-80
Pan, Bin; Yu, Hongwei; Park, John et al. (2015) Painful nerve injury upregulates thrombospondin-4 expression in dorsal root ganglia. J Neurosci Res 93:443-53
Chang, E; Chen, X; Kim, M et al. (2015) Differential effects of voltage-gated calcium channel blockers on calcium channel alpha-2-delta-1 subunit protein-mediated nociception. Eur J Pain 19:639-48
Zhou, C; Luo, Z D (2015) Nerve injury-induced calcium channel alpha-2-delta-1 protein dysregulation leads to increased pre-synaptic excitatory input into deep dorsal horn neurons and neuropathic allodynia. Eur J Pain 19:1267-76

Showing the most recent 10 out of 18 publications