Central Mechanisms Mediating Thrombospondin-4-induced Pain States

John Park; Yanhui Peter Yu; Chun-Yi Zhou; Kang-Wu Li; Dongqing Wang; Eric Chang; Doo-Sik Kim; Benjamin Vo; Xia Zhang; Nian Gong; Kelli Sharp; Oswald Steward; Iuliia Vitko; Edward Perez-Reyes; Cagla Eroglu; Ben Barres; Frank Zaucke; Guoping Feng; Z. David Luo

doi:10.1074/jbc.M116.723478

Central Mechanisms Mediating Thrombospondin-4-induced Pain States*

From the ^‡Department of Pharmacology and
^§Department of Anesthesiology and Perioperative Care, University of California, Irvine, California 92697,
^¶Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,
^‖Reeve-Irvine Research Center, University of California, Irvine, School of Medicine, Irvine, California 92697,
^**Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22908,
^‡‡Cell Biology, Duke University Medical Center, Durham, North Carolina 27710,
^¶¶Department of Neurobiology, Stanford University, Stanford, California 94305, and
^‖‖Center for Biochemistry and Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, D50931 Cologne, Germany

↵4 To whom correspondence should be addressed: Dept. of Anesthesiology and Perioperative Care, University of California Irvine, Gillespie Bldg., Rm. 3113, 837 Health Sci. Rd., Irvine, CA 92697. Tel.: 949-824-7469; Fax: 949-824-7447; E-mail: zluo{at}uci.edu.

↵1 These authors contributed equally to the work.

Abstract

Peripheral nerve injury induces increased expression of thrombospondin-4 (TSP4) in spinal cord and dorsal root ganglia that contributes to neuropathic pain states through unknown mechanisms. Here, we test the hypothesis that TSP4 activates its receptor, the voltage-gated calcium channel Ca_vα₂δ₁ subunit (Ca_vα₂δ₁), on sensory afferent terminals in dorsal spinal cord to promote excitatory synaptogenesis and central sensitization that contribute to neuropathic pain states. We show that there is a direct molecular interaction between TSP4 and Ca_vα₂δ₁ in the spinal cord in vivo and that TSP4/Ca_vα₂δ₁-dependent processes lead to increased behavioral sensitivities to stimuli. In dorsal spinal cord, TSP4/Ca_vα₂δ₁-dependent processes lead to increased frequency of miniature and amplitude of evoked excitatory post-synaptic currents in second-order neurons as well as increased VGlut₂- and PSD95-positive puncta, indicative of increased excitatory synapses. Blockade of TSP4/Ca_vα₂δ₁-dependent processes with Ca_vα₂δ₁ ligand gabapentin or genetic Ca_vα₂δ₁ knockdown blocks TSP4 induced nociception and its pathological correlates. Conversely, TSP4 antibodies or genetic ablation blocks nociception and changes in synaptic transmission in mice overexpressing Ca_vα₂δ₁. Importantly, TSP4/Ca_vα₂δ₁-dependent processes also lead to similar behavioral and pathological changes in a neuropathic pain model of peripheral nerve injury. Thus, a TSP4/Ca_vα₂δ₁-dependent pathway activated by TSP4 or peripheral nerve injury promotes exaggerated presynaptic excitatory input and evoked sensory neuron hyperexcitability and excitatory synaptogenesis, which together lead to central sensitization and pain state development.

Footnotes

↵2 Recipient of a Pre-Doctoral Fellowship in Pharmacology/Toxicology from the Pharmaceutical Research and Manufacturers of America Foundation (PRMAF-52427).
↵3 Recipient of National Institutes of Health Rehabilitation Medicine Scientist Training Program fellowship (K-12) and faculty career development (KL-2) fellowship from the Institute for Clinical and Translational Science.
↵* This work was supported, in part, through access to the confocal facility of the Optical Biology Shared Resource of the Cancer Center, Support Grant CA-62203, at the University of California Irvine and by National Institutes of Health Grants NS069524 (to E. P.-R.), NS40135, DE014545, and NS064341 (to Z. D. L.), and DE021847 (to O. S. and Z. D. L).The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.