1
|
Pathogenic mechanisms of lipid mediator lysophosphatidic acid in chronic pain. Prog Lipid Res 2020; 81:101079. [PMID: 33259854 DOI: 10.1016/j.plipres.2020.101079] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023]
Abstract
A number of membrane lipid-derived mediators play pivotal roles in the initiation, maintenance, and regulation of various types of acute and chronic pain. Acute pain, comprising nociceptive and inflammatory pain warns us about the presence of damage or harmful stimuli. However, it can be efficiently reversed by opioid analgesics and anti-inflammatory drugs. Prostaglandin E2 and I2, the representative lipid mediators, are well-known causes of acute pain. However, some lipid mediators such as lipoxins, resolvins or endocannabinoids suppress acute pain. Various types of peripheral and central neuropathic pain (NeuP) as well as fibromyalgia (FM) are representatives of chronic pain and refractory owing to abnormal pain processing distinct from acute pain. Accumulating evidence demonstrated that lipid mediators represented by lysophosphatidic acid (LPA) are involved in the initiation and maintenance of both NeuP and FM in experimental animal models. The LPAR1-mediated peripheral mechanisms including dorsal root demyelination, Cavα2δ1 expression in dorsal root ganglion, and LPAR3-mediated amplification of central LPA production via glial cells are involved in the series of molecular mechanisms underlying NeuP. This review also discusses the involvement of lipid mediators in emerging research directives, including itch-sensing, sexual dimorphism, and the peripheral immune system.
Collapse
|
2
|
Hepsen S, Akhanli P, Sakiz D, Sencar ME, Ucan B, Unsal IO, Cakal E, Ozbek M. The effects of patient and disease-related factors on the quality of life in patients with hypoparathyroidism. Arch Osteoporos 2020; 15:75. [PMID: 32430780 DOI: 10.1007/s11657-020-00759-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/11/2020] [Indexed: 02/07/2023]
Abstract
UNLABELLED This study aims to evaluate factors affecting the quality of life (QOL) of hypoparathyroidism. While QOL is reduced in post-surgical and non-surgical groups, mental health seems to be less affected in non-surgical patients. Having an additional disease affects QOL negatively but having thyroid cancer may not change the QOL results. PURPOSE Hypoparathyroidism (HypoPT) is an orphan disease, which causes physical, emotional, and cognitive problems. We aimed to estimate the factors affecting the quality of life (QOL) of HypoPT patients. METHODS Basal characteristics, treatments, and laboratory results of the participants were recorded. QOL of the patients and controls were evaluated via the Short Form-36 (SF-36) survey. RESULTS One hundred sixty HypoPT patients were compared with 148 controls. Patients had lower scores in all SF-36 domains than controls. Non-surgical patients had better scores in vitality and mental health compared with post-surgical ones. Males had higher scores in mental and physical health domains than females. Non-surgical patients had higher scores in mental health compared with post-surgical ones when calcium levels were between 8 and 8.9 mg/dL. When we compared the patients with the pathological results, QOL scores of post-surgical patients with thyroid cancer were not different from the patients with thyroid nodular hyperplasia. HypoPT patients having an additional disease presented lower scores in physical functions and general health. Disease duration was found out positively correlated with vitality in non-surgical patients. CONCLUSION While QOL is reduced in both post-surgical and non-surgical HypoPT groups, mental health seems to be less affected in non-surgical patients. Non-surgical patients might be tolerating hypocalcemia symptoms, lower calcium levels, and longer disease duration better than post-surgical ones. Having an additional disease affects the QOL negatively but having thyroid cancer may not change the QOL results of post-surgical patients.
Collapse
Affiliation(s)
- Sema Hepsen
- Department of Endocrinology and Metabolism, University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey.
| | - Pinar Akhanli
- Department of Endocrinology and Metabolism, University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey
| | - Davut Sakiz
- Department of Endocrinology and Metabolism, University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey
| | - Muhammed Erkam Sencar
- Department of Endocrinology and Metabolism, University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey
| | - Bekir Ucan
- Department of Endocrinology and Metabolism, University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey
| | - Ilknur Ozturk Unsal
- Department of Endocrinology and Metabolism, University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey
| | - Erman Cakal
- Department of Endocrinology and Metabolism, University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey
| | - Mustafa Ozbek
- Department of Endocrinology and Metabolism, University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey
| |
Collapse
|
3
|
Affiliation(s)
- Hiroshi Ueda
- Graduate School of Pharmaceutical Sciences, Kyoto University
| |
Collapse
|
4
|
Dohke T, Iba K, Hanaka M, Kanaya K, Okazaki S, Yamashita T. Teriparatide rapidly improves pain-like behavior in ovariectomized mice in association with the downregulation of inflammatory cytokine expression. J Bone Miner Metab 2018; 36:499-507. [PMID: 28983699 DOI: 10.1007/s00774-017-0865-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 08/20/2017] [Indexed: 12/18/2022]
Abstract
Recent studies have indicated that teriparatide, an anti-osteoporosis agent, significantly improves back pain regardless of the presence of vertebral fracture in osteoporosis patients. The aims of this study were to examine whether teriparatide improves pain-like behavior in an ovariectomized (OVX) mouse model, and to evaluate changes in osteoclast marker levels and inflammatory cytokine expression levels induced by teriparatide treatment in bone tissue in association with improvements in pain-like behavior. OVX and sham operations were performed in 8-week-old mice, followed by teriparatide treatment for 2 weeks. Pain-like behavior tests (von Frey, paw flick and spontaneous pain test), and the measurement of serum tartrate-resistant acid phosphatase 5b (TRAP5b) level and inflammatory cytokine (interleukin [IL]-1β, IL-6 and tumor necrosis factor [TNF]-α) expression levels in the bone tissue were conducted after teriparatide treatment in OVX mice. Pain-like behavior in the von Frey test was significantly improved by teriparatide treatment in OVX mice. With regard to the early phase (within the first 7 days of treatment), teriparatide significantly improved pain-like behavior in the von Frey test, the paw flick test and the spontaneous pain test. Teriparatide significantly inhibited the expression of IL-1β, IL-6 and TNF-α in OVX mice in the early phase of the treatment, while the TRAP5b level in OVX mice was not significantly affected. We demonstrated that the teriparatide-induced rapid improvement effect on pain-like behavior in OVX mice was associated with the downregulation of inflammatory cytokine expression, including IL-1β, IL-6 and TNF-α.
Collapse
Affiliation(s)
- Takayuki Dohke
- Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Kousuke Iba
- Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, Sapporo, Japan.
| | - Megumi Hanaka
- Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Kumiko Kanaya
- Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Shunichiro Okazaki
- Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Toshihiko Yamashita
- Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, Sapporo, Japan
| |
Collapse
|
5
|
Shepherd AJ, Mickle AD, McIlvried LA, Gereau RW, Mohapatra DP. Parathyroid hormone-related peptide activates and modulates TRPV1 channel in human DRG neurons. Eur J Pain 2018; 22:1685-1690. [PMID: 29797679 DOI: 10.1002/ejp.1251] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2018] [Indexed: 11/05/2022]
Abstract
Parathyroid hormone-related peptide (PTHrP) is associated with advanced tumor growth and metastasis, especially in breast, prostate and myeloma cancers that metastasize to bones, resulting in debilitating chronic pain conditions. Our recent studies revealed that the receptor for PTHrP, PTH1R, is expressed in mouse DRG sensory neurons, and its activation leads to flow-activation and modulation of TRPV1 channel function, resulting in peripheral heat and mechanical hypersensitivity. In order to verify the translatability of our findings in rodents to humans, we explored whether this signalling axis operates in primary human DRG sensory neurons. Analysis of gene expression data from recently reported RNA deep sequencing experiments performed on mouse and human DRGs reveals that PTH1R is expressed in DRG and tibial nerve. Furthermore, exposure of cultured human DRG neurons to PTHrP leads to slow-sustained activation of TRPV1 and modulation of capsaicin-induced channel activation. Both activation and modulation of TRPV1 by PTHrP were dependent on PKC activity. Our findings suggest that functional PTHrP/PTH1R-TRPV1 signalling exists in human DRG neurons, which could contribute to local nociceptor excitation in the vicinity of metastatic bone tumor microenvironment.
Collapse
Affiliation(s)
- A J Shepherd
- Department of Anesthesiology, Washington University Pain Center, Washington University in St. Louis School of Medicine, USA
| | - A D Mickle
- Department of Anesthesiology, Washington University Pain Center, Washington University in St. Louis School of Medicine, USA
| | - L A McIlvried
- Department of Anesthesiology, Washington University Pain Center, Washington University in St. Louis School of Medicine, USA
| | - R W Gereau
- Department of Anesthesiology, Washington University Pain Center, Washington University in St. Louis School of Medicine, USA
| | - D P Mohapatra
- Department of Anesthesiology, Washington University Pain Center, Washington University in St. Louis School of Medicine, USA.,Center for the Investigation of Membrane Excitable Diseases, Washington University in St. Louis School of Medicine, USA
| |
Collapse
|
6
|
Shepherd AJ, Mickle AD, Kadunganattil S, Hu H, Mohapatra DP. Parathyroid Hormone-Related Peptide Elicits Peripheral TRPV1-dependent Mechanical Hypersensitivity. Front Cell Neurosci 2018; 12:38. [PMID: 29497363 PMCID: PMC5818411 DOI: 10.3389/fncel.2018.00038] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 01/31/2018] [Indexed: 02/04/2023] Open
Abstract
Bone metastasis in breast, prostate and lung cancers often leads to chronic pain, which is poorly managed by existing analgesics. The neurobiological mechanisms that underlie chronic pain associated with bone-metastasized cancers are not well understood, but sensitization of peripheral nociceptors by tumor microenvironment factors has been demonstrated to be important. Parathyroid hormone-related peptide (PTHrP) is highly expressed in bone-metastasized breast and prostate cancers, and is critical to growth and proliferation of these tumors in the bone tumor microenvironment. Previous studies have suggested that PTHrP could sensitize nociceptive sensory neurons, resulting in peripheral pain hypersensitivity. In this study, we found that PTHrP induces both heat and mechanical hypersensitivity, that are dependent on the pain-transducing transient receptor potential channel family vanilloid, member-1 (TRPV1), but not the mechano-transducing TRPV4 and TRPA1 ion channels. Functional ratiometric Ca2+ imaging and voltage-clamp electrophysiological analysis of cultured mouse DRG neurons show significant potentiation of TRPV1, but not TRPA1 or TRPV4 channel activation by PTHrP. Interestingly, PTHrP exposure led to the slow and sustained activation of TRPV1, in the absence of any exogenous channel agonist, and is dependent on the expression of the type-1 parathyroid hormone receptor (PTH1), as well as on downstream phosphorylation of the channel by protein kinase C (PKC). Accordingly, local administration of specific small-molecule antagonists of TRPV1 to mouse hindpaws after the development of PTHrP-induced mechanical hypersensitivity led to its significant attenuation. Collectively, our findings suggest that PTHrP/PTH1-mediated flow activation of TRPV1 channel contributes at least in part to the development and maintenance of peripheral mechanical pain hypersensitivity, and could therefore constitute a mechanism for nociceptor sensitization in the context of metastatic bone cancer pain.
Collapse
Affiliation(s)
- Andrew J Shepherd
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, United States.,Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
| | - Aaron D Mickle
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, United States.,Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
| | - Suraj Kadunganattil
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
| | - Hongzhen Hu
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO, United States.,Center for the Study of Itch, Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO, United States.,Center for Investigation on Membrane Excitable Diseases, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
| | - Durga P Mohapatra
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, United States.,Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO, United States.,Center for the Study of Itch, Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO, United States.,Center for Investigation on Membrane Excitable Diseases, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
| |
Collapse
|
7
|
Lysophosphatidic acid signaling is the definitive mechanism underlying neuropathic pain. Pain 2017; 158 Suppl 1:S55-S65. [DOI: 10.1097/j.pain.0000000000000813] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
8
|
Induction of thermal and mechanical hypersensitivity by parathyroid hormone-related peptide through upregulation of TRPV1 function and trafficking. Pain 2016; 156:1620-1636. [PMID: 25970319 DOI: 10.1097/j.pain.0000000000000224] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The neurobiological mechanisms underlying chronic pain associated with cancers are not well understood. It has been hypothesized that factors specifically elevated in the tumor microenvironment sensitize adjacent nociceptive afferents. We show that parathyroid hormone-related peptide (PTHrP), which is found at elevated levels in the tumor microenvironment of advanced breast and prostate cancers, is a critical modulator of sensory neurons. Intraplantar injection of PTHrP led to the development of thermal and mechanical hypersensitivity in both male and female mice, which were absent in mice lacking functional transient receptor potential vanilloid-1 (TRPV1). The PTHrP treatment of cultured mouse sensory neurons enhanced action potential firing, and increased TRPV1 activation, which was dependent on protein kinase C (PKC) activity. Parathyroid hormone-related peptide induced robust potentiation of TRPV1 activation and enhancement of neuronal firing at mild acidic pH that is relevant to acidic tumor microenvironment. We also observed an increase in plasma membrane TRPV1 protein levels after exposure to PTHrP, leading to upregulation in the proportion of TRPV1-responsive neurons, which was dependent on the activity of PKC and Src kinases. Furthermore, co-injection of PKC or Src inhibitors attenuated PTHrP-induced thermal but not mechanical hypersensitivity. Altogether, our results suggest that PTHrP and mild acidic conditions could induce constitutive pathological activation of sensory neurons through upregulation of TRPV1 function and trafficking, which could serve as a mechanism for peripheral sensitization of nociceptive afferents in the tumor microenvironment.
Collapse
|
9
|
Magerl W, Burkart D, Fernandez A, Schmidt LG, Treede RD. Persistent antinociception through repeated self-injury in patients with borderline personality disorder. Pain 2012; 153:575-584. [DOI: 10.1016/j.pain.2011.11.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 11/16/2011] [Accepted: 11/18/2011] [Indexed: 12/21/2022]
|
10
|
Dobolyi A, Dimitrov E, Palkovits M, Usdin TB. The neuroendocrine functions of the parathyroid hormone 2 receptor. Front Endocrinol (Lausanne) 2012; 3:121. [PMID: 23060860 PMCID: PMC3465808 DOI: 10.3389/fendo.2012.00121] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 09/20/2012] [Indexed: 01/25/2023] Open
Abstract
The G-protein coupled parathyroid hormone 2 receptor (PTH2R) is concentrated in endocrine and limbic regions in the forebrain. Its endogenous ligand, tuberoinfundibular peptide of 39 residues (TIP39), is synthesized in only two brain regions, within the posterior thalamus and the lateral pons. TIP39-expressing neurons have a widespread projection pattern, which matches the PTH2R distribution in the brain. Neuroendocrine centers including the preoptic area, the periventricular, paraventricular, and arcuate nuclei contain the highest density of PTH2R-positive networks. The administration of TIP39 and an antagonist of the PTH2R as well as the investigation of mice that lack functional TIP39 and PTH2R revealed the involvement of the PTH2R in a variety of neural and neuroendocrine functions. TIP39 acting via the PTH2R modulates several aspects of the stress response. It evokes corticosterone release by activating corticotropin-releasing hormone-containing neurons in the hypothalamic paraventricular nucleus. Block of TIP39 signaling elevates the anxiety state of animals and their fear response, and increases stress-induced analgesia. TIP39 has also been suggested to affect the release of additional pituitary hormones including arginine-vasopressin and growth hormone. A role of the TIP39-PTH2R system in thermoregulation was also identified. TIP39 may play a role in maintaining body temperature in a cold environment via descending excitatory pathways from the preoptic area. Anatomical and functional studies also implicated the TIP39-PTH2R system in nociceptive information processing. Finally, TIP39 induced in postpartum dams may play a role in the release of prolactin during lactation. Potential mechanisms leading to the activation of TIP39 neurons and how they influence the neuroendocrine system are also described. The unique TIP39-PTH2R neuromodulator system provides the possibility for developing drugs with a novel mechanism of action to control neuroendocrine disorders.
Collapse
Affiliation(s)
- Arpád Dobolyi
- Neuromorphological and Neuroendocrine Research Laboratory, Department of Anatomy, Histology and Embryology, Hungarian Academy of Sciences, Semmelweis UniversityBudapest, Hungary
- *Correspondence: Arpád Dobolyi, Neuromorphological and Neuroendocrine Research Laboratory, Department of Anatomy, Histology and Embryology, Hungarian Academy of Sciences, Semmelweis University, Tűzoltó u. 58, Budapest H-1094, Hungary. e-mail:
| | - Eugene Dimitrov
- Section on Fundamental Neuroscience, National Institute of Mental Health, National Institute of HealthBethesda, MD, USA
| | - Miklós Palkovits
- Neuromorphological and Neuroendocrine Research Laboratory, Department of Anatomy, Histology and Embryology, Hungarian Academy of Sciences, Semmelweis UniversityBudapest, Hungary
| | - Ted B. Usdin
- Section on Fundamental Neuroscience, National Institute of Mental Health, National Institute of HealthBethesda, MD, USA
| |
Collapse
|
11
|
Nozaki C, Vergnano AM, Filliol D, Ouagazzal AM, Le Goff A, Carvalho S, Reiss D, Gaveriaux-Ruff C, Neyton J, Paoletti P, Kieffer BL. Zinc alleviates pain through high-affinity binding to the NMDA receptor NR2A subunit. Nat Neurosci 2011; 14:1017-22. [PMID: 21725314 DOI: 10.1038/nn.2844] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 04/19/2011] [Indexed: 02/07/2023]
Abstract
Zinc is abundant in the central nervous system and regulates pain, but the underlying mechanisms are unknown. In vitro studies have shown that extracellular zinc modulates a plethora of signaling membrane proteins, including NMDA receptors containing the NR2A subunit, which display exquisite zinc sensitivity. We created NR2A-H128S knock-in mice to investigate whether Zn2+-NR2A interaction influences pain control. In these mice, high-affinity (nanomolar) zinc inhibition of NMDA currents was lost in the hippocampus and spinal cord. Knock-in mice showed hypersensitivity to radiant heat and capsaicin, and developed enhanced allodynia in inflammatory and neuropathic pain models. Furthermore, zinc-induced analgesia was completely abolished under both acute and chronic pain conditions. Our data establish that zinc is an endogenous modulator of excitatory neurotransmission in vivo and identify a new mechanism in pain processing that relies on NR2A NMDA receptors. The study also potentially provides a molecular basis for the pain-relieving effects of dietary zinc supplementation.
Collapse
Affiliation(s)
- Chihiro Nozaki
- Institut de Génétique et Biologie Moléculaire et Cellulaire, Illkirch, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Abraham-Nordling M, Persson B, Nordling E. Model of the complex of Parathyroid hormone-2 receptor and Tuberoinfundibular peptide of 39 residues. BMC Res Notes 2010; 3:270. [PMID: 20979597 PMCID: PMC2991341 DOI: 10.1186/1756-0500-3-270] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 10/27/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND We aim to propose interactions between the parathyroid hormone-2 receptor (PTH2R) and its ligand the tuberoinfundibular peptide of 39 residues (TIP39) by constructing a homology model of their complex. The two related peptides parathyroid hormone (PTH) and parathyroid hormone related protein (PTHrP) are compared with the complex to examine their interactions. FINDINGS In the model, the hydrophobic N-terminus of TIP39 is buried in a hydrophobic part of the central cavity between helices 3 and 7. Comparison of the peptide sequences indicates that the main discriminator between the agonistic peptides TIP39 and PTH and the inactive PTHrP is a tryptophan-phenylalanine replacement. The model indicates that the smaller phenylalanine in PTHrP does not completely occupy the binding site of the larger tryptophan residue in the other peptides. As only TIP39 causes internalisation of the receptor and the primary difference being an aspartic acid in position 7 of TIP39 that interacts with histidine 396 in the receptor, versus isoleucine/histidine residues in the related hormones, this might be a trigger interaction for the events that cause internalisation. CONCLUSIONS A model is constructed for the complex and a trigger interaction for full agonistic activation between aspartic acid 7 of TIP39 and histidine 396 in the receptor is proposed.
Collapse
Affiliation(s)
- Mirna Abraham-Nordling
- Division of Surgery, Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden.
| | | | | |
Collapse
|
13
|
Dimitrov EL, Petrus E, Usdin TB. Tuberoinfundibular peptide of 39 residues (TIP39) signaling modulates acute and tonic nociception. Exp Neurol 2010; 226:68-83. [PMID: 20696160 DOI: 10.1016/j.expneurol.2010.08.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 07/26/2010] [Accepted: 08/02/2010] [Indexed: 11/19/2022]
Abstract
Tuberoinfundibular peptide of 39 residues (TIP39) synthesizing neurons at the caudal border of the thalamus and in the lateral pons project to areas rich in its receptor, the parathyroid hormone 2 receptor (PTH2R). These areas include many involved in processing nociceptive information. Here we examined the potential role of TIP39 signaling in nociception using a PTH2R antagonist (HYWH) and mice with deletion of TIP39's coding sequence or PTH2R null mutation. Intracerebroventricular (icv) infusion of HYWH significantly inhibited nociceptive responses in tail-flick and hot-plate tests and attenuated the nociceptive response to hindpaw formalin injection. TIP39-KO and PTH2R-KO had increased response latency in the 55°C hot-plate test and reduced responses in the hindpaw formalin test. The tail-flick test was not affected in either KO line. Thermal hypoalgesia in KO mice was dose-dependently reversed by systemic administration of the cannabinoid receptor 1 (CB1) antagonist rimonabant, which did not affect nociception in wild-type (WT). Systemic administration of the cannabinoid agonist CP 55,940 did not affect nociception in KO mice at a dose effective in WT. WT mice administered HYWH icv, and both KOs, had significantly increased stress-induced analgesia (SIA). Rimonabant blocked the increased SIA in TIP39-KO, PTH2R-KO or after HYWH infusion. CB1 and FAAH mRNA were decreased and increased, respectively, in the basolateral amygdala of TIP39-KO mice. These data suggest that TIP39 signaling modulates nociception, very likely by inhibiting endocannabinoid circuitry at a supraspinal level. We infer a new central mechanism for endocannabinoid regulation, via TIP39 acting on the PTH2R in discrete brain regions.
Collapse
MESH Headings
- Amidohydrolases/metabolism
- Animals
- Cannabinoid Receptor Modulators/metabolism
- Formaldehyde
- In Situ Hybridization
- Injections, Intraventricular
- Injections, Spinal
- Male
- Mice
- Mice, Knockout
- Naloxone/pharmacology
- Narcotic Antagonists/pharmacology
- Neuropeptides/administration & dosage
- Neuropeptides/pharmacology
- Nociceptors/drug effects
- Nociceptors/physiology
- Pain/pathology
- Pain/physiopathology
- Pain Measurement/drug effects
- Piperidines/pharmacology
- Pyrazoles/pharmacology
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/biosynthesis
- Receptor, Parathyroid Hormone, Type 2/biosynthesis
- Receptor, Parathyroid Hormone, Type 2/genetics
- Rimonabant
- Signal Transduction/physiology
- Stress, Psychological/psychology
- Synapses/physiology
- Vesicular Glutamate Transport Protein 2/biosynthesis
- Vesicular Glutamate Transport Protein 2/genetics
Collapse
Affiliation(s)
- Eugene L Dimitrov
- Section on Fundamental Neuroscience, National Institute of Mental Health, 35 Convent Drive, Room 1B-213, Bethesda, MD 20892, USA.
| | | | | |
Collapse
|