Persistent Link:
http://hdl.handle.net/10150/578606
Title:
Bradykinin Ligands and Receptors Involved in Neuropathic Pain
Author:
Hall, Sara M.
Issue Date:
2015
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Neuropathic pain is a prevalent disease with no effective, safe treatments and limited knowledge on the mechanisms involved. One target for neuropathic pain treatment may be the blockade of Dynorphin A (Dyn A). Dyn A is a unique endogenous ligand that possesses well-known neuroinhibitory effects via opioid receptors and neuroexcitatory effects that are mediated through the bradykinin 2 receptors (B2Rs). Extensive SAR was carried out to develop a ligand for the blockade of the excitatory actions of Dyn A at the B2R. A lead ligand was able to block Dyn A-induced hyperalgesia in naïve animals and was effective in a neuropathic pain model. However, the ligand was susceptible to enzymatic degradation. In an effort to increase the stability, modifications of the ligand using non-natural amino acids were performed. Analogues substituted at or near the N-terminus with a D-isomer retained binding at the receptor as well as provided a large increase in stability. These ligands were also found to be non-toxic in a cell toxicity assay. Dyn A has been found to not activate the classical signaling of the B2R, PI hydrolysis or Ca²⁺ mobilization. In an effort to determine Dyn A's signaling, a study was done examining up-regulation of phosphorylated proteins. It was found that Dyn A did not activate; pERK, 7 PKC isoforms or PKA. A well known B2R antagonist, HOE140, was found to have low affinity at rat and guinea pig brain B2Rs but high affinity in the guinea pig ileum. Further examination revealed that this discrepancy in binding may arise from a different isoform of the B2R that has not been previously examined. To date, we have discovered Dyn A analogues that have high affinity for the B2R, are very stable, and have low toxicity. The signaling pathway is still not fully understood, but further studies are underway. Also, there is evidence that the B2R in which the analogues are interacting at may be a different form than what has previously been described. Targeting this different isoform of the B2R with our current stable ligands may provide beneficial therapeutics for the treatment of neuropathic pain without the cardiovascular liabilities.
Type:
text; Electronic Dissertation
Keywords:
neuropathic pain; non-opioid Dynorphin A; structure activity relationship; Biochemistry; bradykinin receptors
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Biochemistry
Degree Grantor:
University of Arizona
Advisor:
Hruby, Victor J.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen
dc.titleBradykinin Ligands and Receptors Involved in Neuropathic Painen_US
dc.creatorHall, Sara M.en
dc.contributor.authorHall, Sara M.en
dc.date.issued2015en
dc.publisherThe University of Arizona.en
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en
dc.description.abstractNeuropathic pain is a prevalent disease with no effective, safe treatments and limited knowledge on the mechanisms involved. One target for neuropathic pain treatment may be the blockade of Dynorphin A (Dyn A). Dyn A is a unique endogenous ligand that possesses well-known neuroinhibitory effects via opioid receptors and neuroexcitatory effects that are mediated through the bradykinin 2 receptors (B2Rs). Extensive SAR was carried out to develop a ligand for the blockade of the excitatory actions of Dyn A at the B2R. A lead ligand was able to block Dyn A-induced hyperalgesia in naïve animals and was effective in a neuropathic pain model. However, the ligand was susceptible to enzymatic degradation. In an effort to increase the stability, modifications of the ligand using non-natural amino acids were performed. Analogues substituted at or near the N-terminus with a D-isomer retained binding at the receptor as well as provided a large increase in stability. These ligands were also found to be non-toxic in a cell toxicity assay. Dyn A has been found to not activate the classical signaling of the B2R, PI hydrolysis or Ca²⁺ mobilization. In an effort to determine Dyn A's signaling, a study was done examining up-regulation of phosphorylated proteins. It was found that Dyn A did not activate; pERK, 7 PKC isoforms or PKA. A well known B2R antagonist, HOE140, was found to have low affinity at rat and guinea pig brain B2Rs but high affinity in the guinea pig ileum. Further examination revealed that this discrepancy in binding may arise from a different isoform of the B2R that has not been previously examined. To date, we have discovered Dyn A analogues that have high affinity for the B2R, are very stable, and have low toxicity. The signaling pathway is still not fully understood, but further studies are underway. Also, there is evidence that the B2R in which the analogues are interacting at may be a different form than what has previously been described. Targeting this different isoform of the B2R with our current stable ligands may provide beneficial therapeutics for the treatment of neuropathic pain without the cardiovascular liabilities.en
dc.typetexten
dc.typeElectronic Dissertationen
dc.subjectneuropathic painen
dc.subjectnon-opioid Dynorphin Aen
dc.subjectstructure activity relationshipen
dc.subjectBiochemistryen
dc.subjectbradykinin receptorsen
thesis.degree.namePh.D.en
thesis.degree.leveldoctoralen
thesis.degree.disciplineGraduate Collegeen
thesis.degree.disciplineBiochemistryen
thesis.degree.grantorUniversity of Arizonaen
dc.contributor.advisorHruby, Victor J.en
dc.contributor.committeememberHruby, Victor J.en
dc.contributor.committeememberHorton, Nancyen
dc.contributor.committeememberJewett, Johnen
dc.contributor.committeememberLai, Josephineen
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