Heteromerization of the μ- and δ-Opioid Receptors Produces Ligand-Biased Antagonism and Alters μ-Receptor Trafficking

Heteromerization of opioid receptors has been shown to alter opioid receptor pharmacology. However, how receptor heteromerization affects the processes of endocytosis and postendocytic sorting has not been closely examined. This question is of particular relevance for heteromers of the μ-opioid receptor (MOR) and δ-opioid receptor (DOR), because the MOR is recycled primarily after endocytosis and the DOR is degraded in the lysosome. Here, we examined the endocytic and postendocytic fate of MORs, DORs, and DOR/MOR heteromers in human embryonic kidney 293 cells stably expressing each receptor alone or coexpressing both receptors. We found that the clinically relevant MOR agonist methadone promotes endocytosis of MOR but also the DOR/MOR heteromer. Furthermore, we show that DOR/MOR heteromers that are endocytosed in response to methadone are targeted for degradation, whereas MORs in the same cell are significantly more stable. It is noteworthy that we found that the DOR-selective antagonist naltriben mesylate could block both methadone- and [d-Ala2,NMe-Phe4,Gly-ol5]-enkephalin-induced endocytosis of the DOR/MOR heteromers but did not block signaling from this heteromer. Together, our results suggest that the MOR adopts novel trafficking properties in the context of the DOR/MOR heteromer. In addition, they suggest that the heteromer shows “biased antagonism,” whereby DOR antagonist can inhibit trafficking but not signaling of the DOR/MOR heteromer.

[1]  Shaoqiu He,et al.  Facilitation of μ-Opioid Receptor Activity by Preventing δ-Opioid Receptor-Mediated Codegradation , 2011, Neuron.

[2]  R. Bodnar.  Endogenous opiates and behavior: 2009 , 2010, Peptides.

[3]  G. Balboni,et al.  Agonists at the δ‐opioid receptor modify the binding of µ‐receptor agonists to the µ–δ receptor hetero‐oligomer , 2010, British journal of pharmacology.

[4]  J. Mulder,et al.  Increased Abundance of Opioid Receptor Heteromers After Chronic Morphine Administration , 2010, Science Signaling.

[5]  T. Hökfelt,et al.  Coexpression of δ- and μ-opioid receptors in nociceptive sensory neurons , 2010, Proceedings of the National Academy of Sciences.

[6]  L. Devi,et al.  Receptor heteromerization and drug discovery. , 2010, Trends in pharmacological sciences.

[7]  P. Portoghese,et al.  Standard opioid agonists activate heteromeric opioid receptors: evidence for morphine and [d-Ala(2)-MePhe(4)-Glyol(5)]enkephalin as selective μ-δ agonists. , 2010, ACS chemical neuroscience.

[8]  A. Basbaum,et al.  Dissociation of the Opioid Receptor Mechanisms that Control Mechanical and Heat Pain , 2009, Cell.

[9]  L. Devi,et al.  Cell surface targeting of μ-δ opioid receptor heterodimers by RTP4 , 2008, Proceedings of the National Academy of Sciences.

[10]  M. Low,et al.  Differential Activation and Trafficking of μ-Opioid Receptors in Brain Slices , 2008, Molecular Pharmacology.

[11]  Yingjian Liang,et al.  Membrane glycoprotein M6A promotes μ-opioid receptor endocytosis and facilitates receptor sorting into the recycling pathway , 2008, Cell Research.

[12]  Y. Sarne,et al.  Agonist-specific down regulation of mu-opioid receptors: Different cellular pathways are activated by different opioid agonists. , 2008, Life sciences.

[13]  G. Piñeyro,et al.  Src promotes delta opioid receptor (DOR) desensitization by interfering with receptor recycling , 2008, Journal of cellular and molecular medicine.

[14]  A. Marchese,et al.  G protein-coupled receptor sorting to endosomes and lysosomes. , 2008, Annual review of pharmacology and toxicology.

[15]  B. O'dowd,et al.  Trafficking of preassembled opioid μ-δ heterooligomer-Gz signaling complexes to the plasma membrane: Coregulation by agonists , 2007 .

[16]  L. Devi,et al.  Receptor heterodimerization leads to a switch in signaling: β‐arrestin2‐mediated ERK activation by μ‐δ opioid receptor heterodimers , 2007 .

[17]  B. Bie,et al.  Trafficking of central opioid receptors and descending pain inhibition , 2007, Molecular pain.

[18]  S. Ananthan.  Opioid ligands with mixed μ/δ opioid receptor interactions: An emerging approach to novel analgesics , 2006, The AAPS Journal.

[19]  David J. Daniels,et al.  Opioid-induced tolerance and dependence in mice is modulated by the distance between pharmacophores in a bivalent ligand series. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[20]  Susan R. George,et al.  A Role for the Distal Carboxyl Tails in Generating the Novel Pharmacology and G Protein Activation Profile of μ and δ Opioid Receptor Hetero-oligomers* , 2005, Journal of Biological Chemistry.

[21]  Jamie Fong,et al.  A heterodimer-selective agonist shows in vivo relevance of G protein-coupled receptor dimers. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[22]  S. Allouche,et al.  Different Regulation of Human δ-Opioid Receptors by SNC-80 [(+)-4-[(αR)-α-((2S,5R)-4-Allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl]-N,N-diethylbenzamide] and Endogenous Enkephalins , 2004, Journal of Pharmacology and Experimental Therapeutics.

[23]  Lakshmi A. Devi,et al.  A role for heterodimerization of μ and δ opiate receptors in enhancing morphine analgesia , 2004 .

[24]  U. Fuhr,et al.  Affinities of dihydrocodeine and its metabolites to opioid receptors. , 2002, Pharmacology & toxicology.

[25]  M. von Zastrow,et al.  Modulation of Postendocytic Sorting of G Protein-Coupled Receptors , 2002, Science.

[26]  D. Grandy,et al.  μ-Opioid Receptors: Ligand-Dependent Activation of Potassium Conductance, Desensitization, and Internalization , 2002, The Journal of Neuroscience.

[27]  J. Whistler,et al.  Endocytosis of the Mu Opioid Receptor Reduces Tolerance and a Cellular Hallmark of Opiate Withdrawal , 2001, Neuron.

[28]  E. Kostenis.  Is Gα16 the optimal tool for fishing ligands of orphan G-protein-coupled receptors? , 2001 .

[29]  H. Szeto,et al.  Resensitization of Blood Pressure Response to &mgr;-Opioid Peptide Agonists After Acute Desensitization , 2001, Anesthesia and analgesia.

[30]  Kee-Won Kim,et al.  Pharmacological effects of naltriben as a ligand for opioid μ and κ receptors in rat cerebral cortex , 2001 .

[31]  Lakshmi A. Devi,et al.  Heterodimerization of μ and δ Opioid Receptors: A Role in Opiate Synergy , 2000, The Journal of Neuroscience.

[32]  B. O'dowd,et al.  Oligomerization of mu- and delta-opioid receptors. Generation of novel functional properties. , 2000, The Journal of biological chemistry.

[33]  H. Loh,et al.  Receptor density and recycling affect the rate of agonist-induced desensitization of mu-opioid receptor. , 2000, Molecular pharmacology.

[34]  M. Zastrow,et al.  Downregulation of G protein-coupled receptors , 2000, Current Opinion in Neurobiology.

[35]  Lakshmi A. Devi,et al.  G-protein-coupled receptor heterodimerization modulates receptor function , 1999, Nature.

[36]  J. Whistler,et al.  Morphine-activated opioid receptors elude desensitization by β-arrestin , 1998 .

[37]  M. Caron,et al.  Molecular mechanisms of G protein-coupled receptor desensitization and resensitization. , 1998, Life sciences.

[38]  D. Lissin,et al.  mu-Opioid receptor internalization: opiate drugs have differential effects on a conserved endocytic mechanism in vitro and in the mammalian brain. , 1998, Molecular pharmacology.

[39]  L. Devi,et al.  Dimerization of the delta opioid receptor: implication for a role in receptor internalization. , 1997, The Journal of biological chemistry.

[40]  C. Kuhn,et al.  Differential effects of naltrindole on morphine-induced tolerance and physical dependence in rats. , 1997, The Journal of pharmacology and experimental therapeutics.

[41]  T. Coderre,et al.  Attenuation of morphine tolerance and dependence with the highly selective δ-opioid receptor antagonist TIPP[ψ] , 1995 .

[42]  G. Bell,et al.  Pharmacological characterization of the cloned kappa-, delta-, and mu-opioid receptors. , 1994, Molecular pharmacology.

[43]  P. Portoghese,et al.  Selective blockage of delta opioid receptors prevents the development of morphine tolerance and dependence in mice. , 1991, The Journal of pharmacology and experimental therapeutics.

[44]  L. Devi,et al.  Receptor heterodimerization leads to a switch in signaling: beta-arrestin2-mediated ERK activation by mu-delta opioid receptor heterodimers. , 2007, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[45]  C. Cahill,et al.  Trafficking of δ-opioid receptors and other G-protein-coupled receptors: implications for pain and analgesia , 2007 .

[46]  B. O'dowd,et al.  Trafficking of preassembled opioid mu-delta heterooligomer-Gz signaling complexes to the plasma membrane: coregulation by agonists. , 2007, Biochemistry.

[47]  S. Allouche,et al.  Different regulation of human delta-opioid receptors by SNC-80 [(+)-4-[(alphaR)-alpha-((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl]-N,N-diethylbenzamide] and endogenous enkephalins. , 2004, The Journal of pharmacology and experimental therapeutics.

[48]  E. Kostenis.  Is Galpha16 the optimal tool for fishing ligands of orphan G-protein-coupled receptors? , 2001, Trends in pharmacological sciences.

[49]  M. Caron,et al.  Agonist-Specific Regulation of δ-Opioid Receptor Trafficking by G Protein-Coupled Receptor Kinase and β-Arrestin , 1999 .