GPR160 de-orphanization reveals critical roles in neuropathic pain in rodents
Gina L.C. Yosten, Caron M. Harada, Chris Haddock, Luigino Antonio Giancotti, Grant R. Kolar, Ryan Patel, Chun Guo, Zhoumou Chen, Jinsong Zhang, Timothy M. Doyle, Anthony H. Dickenson, Willis K. Samson, Daniela Salvemini
Gina L.C. Yosten, Caron M. Harada, Chris Haddock, Luigino Antonio Giancotti, Grant R. Kolar, Ryan Patel, Chun Guo, Zhoumou Chen, Jinsong Zhang, Timothy M. Doyle, Anthony H. Dickenson, Willis K. Samson, Daniela Salvemini
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Concise Communication Neuroscience

GPR160 de-orphanization reveals critical roles in neuropathic pain in rodents

Abstract

Treating neuropathic pain is challenging and novel non–opioid-based medicines are needed. Using unbiased receptomics, transcriptomic analyses, immunofluorescence, and in situ hybridization, we found that the expression of the orphan GPCR Gpr160 and GPR160 increased in the rodent dorsal horn of the spinal cord following traumatic nerve injury. Genetic and immunopharmacological approaches demonstrated that GPR160 inhibition in the spinal cord prevented and reversed neuropathic pain in male and female rodents without altering normal pain response. GPR160 inhibition in the spinal cord attenuated sensory processing in the thalamus, a key relay in the sensory discriminative pathways of pain. We also identified cocaine- and amphetamine-regulated transcript peptide (CARTp) as a GPR160 ligand. Inhibiting endogenous CARTp signaling in spinal cord attenuated neuropathic pain, whereas exogenous intrathecal CARTp evoked painful hypersensitivity through GPR160-dependent ERK and cAMP response element–binding protein (CREB). Our findings de-orphanize GPR160, identify it as a determinant of neuropathic pain and potential therapeutic target, and provide insights into its signaling pathways. CARTp is involved in many diseases including depression and reward and addiction; de-orphanization of GPR160 is a major step forward understanding the role of CARTp signaling in health and disease.

Authors

Gina L.C. Yosten, Caron M. Harada, Chris Haddock, Luigino Antonio Giancotti, Grant R. Kolar, Ryan Patel, Chun Guo, Zhoumou Chen, Jinsong Zhang, Timothy M. Doyle, Anthony H. Dickenson, Willis K. Samson, Daniela Salvemini

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Figure 4

CARTp induced mechano-hypersensitivity in mice through GPR160-dependent ERK-CREB activation in the spinal cord.

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CARTp induced mechano-hypersensitivity in mice through GPR160-dependent ...
(A) Time-dependent development of mechano-allodynia in mice (n = 4) after i.th. CARTp 55–102 or CARTp 62–102. (B and C) Mechano-allodynia measured 1 hour after i.th. CARTp 55–102 (B, n = 6; C, n = 4) or CARTp 62–102 (B, n = 7; C, n = 5) was reduced with i.th. GPR160 Ab (B, n = 10 and n = 8, respectively) or i.th. CARTp Ab (C, n = 6 and n = 5, respectively). (D and E) When compared with vehicle (D, n = 8; E, n = 4), i.th. CARTp 55–102 induced phosphorylation of ERK (D; p-ERK, n = 9) and CREB (E; p-CREB, n = 6) in the DH-SC, which was attenuated with i.th. coinjections of MEK inhibitor U0126 (D, n = 9; E, n = 5), CREB inhibitor 666-15 (E, n = 5), or GPR160 Ab (D, n = 6). (F) CARTp 55–102–induced mechano-allodynia (n = 20) was attenuated with coinjection of U0126 (n = 20) or 666-15 (n = 6). Vehicles for CARTp, U0126, and 666-15 (n = 17) had no effect on behavior. (G) Proposed model of CARTp/GPR160–induced signaling. Data are expressed as mean ± SD and were analyzed by (A) 2-tailed, 2-way ANOVA with Bonferroni’s multiple-comparisons test or (B–F) 2-tailed, 1-way ANOVA with Dunnett’s multiple-comparisons test. *P < 0.05 versus 0 hours; #P < 0.05 versus Veh; and †P < 0.05 versus respective CARTp plus Veh. PWT, paw withdrawal threshold.