@article{bce6edeab88d4a0da1cd0b4a01259450,
title = "Endosomal signaling of delta opioid receptors is an endogenous mechanism and therapeutic target for relief from inflammatory pain",
abstract = "Whether G protein-coupled receptors signal from endosomes to control important pathophysiological processes and are therapeutic targets is uncertain. We report that opioids from the inflamed colon activate -opioid receptors (DOPr) in endosomes of nociceptors. Biopsy samples of inflamed colonic mucosa from patients and mice with colitis released opioids that activated DOPr on nociceptors to cause a sustained decrease in excitability. DOPr agonists inhibited mechanically sensitive colonic nociceptors. DOPr endocytosis and endosomal signaling by protein kinase C (PKC) and extracellular signal-regulated kinase (ERK) pathways mediated the sustained inhibitory actions of endogenous opioids and DOPr agonists. DOPr agonists stimulated the recruitment of Gi/o and -Arrestin1/2 to endosomes. Analysis of compartmentalized signaling revealed a requirement of DOPr endocytosis for activation of PKC at the plasma membrane and in the cytosol and ERK in the nucleus. We explored a nanoparticle delivery strategy to evaluate whether endosomal DOPr might be a therapeutic target for pain. The DOPr agonist DADLE was coupled to a liposome shell for targeting DOPr-positive nociceptors and incorporated into a mesoporous silica core for release in the acidic and reducing endosomal environment. Nanoparticles activated DOPr at the plasma membrane, were preferentially endocytosed by DOPr-expressing cells, and were delivered to DOPr-positive early endosomes. Nanoparticles caused a long-lasting activation of DOPr in endosomes, which provided sustained inhibition of nociceptor excitability and relief from inflammatory pain. Conversely, nanoparticles containing a DOPr antagonist abolished the sustained inhibitory effects of DADLE. Thus, DOPr in endosomes is an endogenous mechanism and a therapeutic target for relief from chronic inflammatory pain.",
keywords = "G protein-coupled receptors, Inflammation, Nanomedicine, Signaling, pain, Nanoparticles/administration & dosage, Nociceptors/metabolism, Neurons, Colon/innervation, Humans, Signal Transduction/drug effects, Animals, Receptors, Opioid, delta/agonists, HEK293 Cells, Inflammation/complications, Mice, Enkephalin, Leucine-2-Alanine/administration & dosage, Pain/drug therapy",
author = "Jimenez-Vargas, {Nestor N.} and Jing Gong and Wisdom, {Matthew J.} and Jensen, {Dane D.} and Rocco Latorre and Alan Hegron and Shavonne Teng and DiCello, {Jesse J.} and Pradeep Rajasekhar and Veldhuis, {Nicholas A.} and Carbone, {Simona E.} and Yang Yu and Cintya Lopez-Lopez and Josue Jaramillo-Polanco and Meritxell Canals and Reed, {David E.} and Lomax, {Alan E.} and Schmidt, {Brian L.} and Leong, {Kam W.} and Vanner, {Stephen J.} and Halls, {Michelle L.} and Bunnett, {Nigel W.} and Poole, {Daniel P.}",
note = "Funding Information: Author contributions: N.N.J.-V., J.G., D.D.J., R.L., A.H., J.J.D., P.R., N.A.V., S.E.C., Y.Y., C.L.-L., J.J.-P., M.C., D.E.R., A.E.L., B.L.S., K.W.L., S.J.V., M.L.H., N.W.B., and D.P.P. designed research; N.N.J.-V., J.G., M.J.W., D.D.J., R.L., A.H., S.T., J.J.D., P.R., N.A.V., S.E.C., Y.Y., C.L.-L., J.J.-P., D.E.R., and A.E.L. performed research; N.N.J.-V., J.G., M.J.W., D.D.J., R.L., A.H., J.J.D., P.R., N.A.V., S.E.C., Y.Y., C.L.-L., J.J.-P., M.C., D.E.R., A.E.L., B.L.S., K.W.L., S.J.V., M.L.H., N.W.B., and D.P.P. analyzed data; and N.N.J.-V., A.H., B.L.S., K.W.L., S.J.V., M.L.H., N.W.B., and D.P.P. wrote the paper. Competing interest statement: N.W.B. is a founding scientist of Endosome Therapeutics Inc. Research in the laboratories of N.A.V., N.W.B., and D.P.P. is funded in part by Takeda Pharmaceuticals International. This article is a PNAS Direct Submission. Funding Information: ACKNOWLEDGMENTS. We thank Lih En Tiah for technical support and Dr. Malvin Janal for statistical support. The tdRGFP-Rab5a plasmid was designed and validated by Christian LeGouill and Lucas Tabajara Parreiras e Silva from the laboratory of Dr. Michel Bouvier. RGFP-CAAX and β-arrestin2-Rluc2 were provided by the Bouvier laboratory. This work was supported by grants from the NIH (NS102722, DE026806, and DK118971 to B.L.S. and N.W.B.), Department of Defense (W81XWH1810431, to B.L.S. and N.W.B.), Crohn{\textquoteright}s Colitis Canada (D.E.R., A.E.L., and S.J.V.), National Health and Medical Research Council (63303, 1049682, 1031886, 1049730, 1121029, and 1083480 to M.C., M.L.H., N.W.B., and D.P.P.), and Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology (N.W.B.). Publisher Copyright: {\textcopyright} 2020 National Academy of Sciences. All rights reserved.",
year = "2020",
month = jun,
day = "30",
doi = "10.1073/pnas.2000500117",
language = "English (US)",
volume = "117",
pages = "15281--15292",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
publisher = "National Academy of Sciences",
number = "26",
}