1
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Tasma Z, Rees TA, Guo S, Tan S, O'Carroll SJ, Faull RLM, Curtis MA, Christensen SL, Hay DL, Walker CS. Pharmacology of PACAP and VIP receptors in the spinal cord highlights the importance of the PAC 1 receptor. Br J Pharmacol 2024. [PMID: 38616050 DOI: 10.1111/bph.16376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 12/18/2023] [Accepted: 01/20/2024] [Indexed: 04/16/2024] Open
Abstract
BACKGROUND AND PURPOSE The spinal cord is a key structure involved in the transmission and modulation of pain. Pituitary adenylate cyclase-activating peptide (PACAP) and vasoactive intestinal peptide (VIP), are expressed in the spinal cord. These peptides activate G protein-coupled receptors (PAC1, VPAC1 and VPAC2) that could provide targets for the development of novel pain treatments. However, it is not clear which of these receptors are expressed within the spinal cord and how these receptors signal. EXPERIMENTAL APPROACH Dissociated rat spinal cord cultures were used to examine agonist and antagonist receptor pharmacology. Signalling profiles were determined for five signalling pathways. The expression of different PACAP and VIP receptors was then investigated in mouse, rat and human spinal cords using immunoblotting and immunofluorescence. KEY RESULTS PACAP, but not VIP, potently stimulated cAMP, IP1 accumulation and ERK and cAMP response element-binding protein (CREB) but not Akt phosphorylation in spinal cord cultures. Signalling was antagonised by M65 and PACAP6-38. PACAP-27 was more effectively antagonised than either PACAP-38 or VIP. The patterns of PAC1 and VPAC2 receptor-like immunoreactivity appeared to be distinct in the spinal cord. CONCLUSIONS AND IMPLICATIONS The pharmacological profile in the spinal cord suggested that a PAC1 receptor is the major functional receptor subtype present and thus likely mediates the nociceptive effects of the PACAP family of peptides in the spinal cord. However, the potential expression of both PAC1 and VPAC2 receptors in the spinal cord highlights that these receptors may play differential roles and are both possible therapeutic targets.
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Affiliation(s)
- Zoe Tasma
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Tayla A Rees
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Song Guo
- Department of Neurology, Danish Headache Center, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
- Department of Odontology, Panum Institute, Faculty of Health, University of Copenhagen, Copenhagen, Denmark
| | - Sheryl Tan
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Science, The University of Auckland, Auckland, New Zealand
| | - Simon J O'Carroll
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Science, The University of Auckland, Auckland, New Zealand
| | - Richard L M Faull
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Science, The University of Auckland, Auckland, New Zealand
| | - Maurice A Curtis
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Science, The University of Auckland, Auckland, New Zealand
| | - Sarah L Christensen
- Department of Neurology, Danish Headache Center, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Debbie L Hay
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
- Department of Pharmacology and Toxicology, The University of Otago, Dunedin, New Zealand
| | - Christopher S Walker
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
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2
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Kuburas A, Russo AF. Shared and independent roles of CGRP and PACAP in migraine pathophysiology. J Headache Pain 2023; 24:34. [PMID: 37009867 PMCID: PMC10069045 DOI: 10.1186/s10194-023-01569-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/23/2023] [Indexed: 04/04/2023] Open
Abstract
The neuropeptides calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase-activating polypeptide (PACAP) have emerged as mediators of migraine pathogenesis. Both are vasodilatory peptides that can cause migraine-like attacks when infused into people and migraine-like symptoms when injected into rodents. In this narrative review, we compare the similarities and differences between the peptides in both their clinical and preclinical migraine actions. A notable clinical difference is that PACAP, but not CGRP, causes premonitory-like symptoms in patients. Both peptides are found in distinct, but overlapping areas relevant to migraine, most notably with the prevalence of CGRP in trigeminal ganglia and PACAP in sphenopalatine ganglia. In rodents, the two peptides share activities, including vasodilation, neurogenic inflammation, and nociception. Most strikingly, CGRP and PACAP cause similar migraine-like symptoms in rodents that are manifested as light aversion and tactile allodynia. Yet, the peptides appear to act by independent mechanisms possibly by distinct intracellular signaling pathways. The complexity of these signaling pathways is magnified by the existence of multiple CGRP and PACAP receptors that may contribute to migraine pathogenesis. Based on these differences, we suggest PACAP and its receptors provide a rich set of targets to complement and augment the current CGRP-based migraine therapeutics.
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Affiliation(s)
- Adisa Kuburas
- Department of Molecular Physiology and Biophysics and Department of Neurology, University of Iowa, Iowa City, IA, 52242, USA
| | - Andrew F Russo
- Department of Molecular Physiology and Biophysics and Department of Neurology, University of Iowa, Iowa City, IA, 52242, USA.
- Veterans Affairs Medical Center, Iowa City, IA, 52246, USA.
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3
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Zhang L, Zhou Y, Wang Y, Yang L, Wang Y, Shan Z, Liang J, Xiao Z. Inhibiting PAC1 receptor internalization and endosomal ERK pathway activation may ameliorate hyperalgesia in a chronic migraine rat model. Cephalalgia 2023; 43:3331024231163131. [PMID: 36946245 DOI: 10.1177/03331024231163131] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
BACKGROUND Pituitary adenylate cyclase-activating polypeptide (PACAP) is a multipotent neuropeptide widely distributed in the trigeminovascular system (TVS) and higher brain regions. At present, the underlying mechanism of PACAP/PACAP type1 (PAC1) receptor in migraine generation remains unclear. METHODS The rat model of chronic migraine (CM) was established by repeated intraperitoneal injection of nitroglycerin (NTG). Von Frey filaments and hot plate tests were used to measure the mechanical and thermal thresholds. The expression levels of c-Fos, calcitonin gene-related peptide (CGRP), PACAP, PAC1, protein kinase A (PKA) and phosphorylated extracellular signal-regulated kinase (ERK) were assessed by western blotting or immunofluorescence staining. The internalization of PAC1 receptor was visualized by fluorescence microscope and laser scanning confocal microscope. RESULTS The results showed that c-Fos and CGRP expression significantly increased after repeated administrations of NTG or PACAP. Pitstop2 notably improved hyperalgesia in CM rats, while PACAP6-38 offered no benefit. In addition, PACAP-induced PAC1 receptor internalization, PKA and ERK pathways activation were blocked by Pitstop2 instead of PACAP6-38. CONCLUSIONS Our results demonstrate that inhibition of PAC1 receptor internalization could effectively improve allodynia in CM rats by restraining ERK signaling pathway activation in a chronic migraine rat model. Modulation of receptor internalization may be a novel perspective to explore specific mechanisms of PACAP signaling activation in the trigeminal vascular system.
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Affiliation(s)
- Lily Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
- Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yanjie Zhou
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
- Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yajuan Wang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
- Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, China
| | - Liu Yang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
- Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yue Wang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
- Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zhengming Shan
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
- Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jingjing Liang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
- Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zheman Xiao
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
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4
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Guo S, Jansen-Olesen I, Olesen J, Christensen SL. Role of PACAP in migraine: An alternative to CGRP? Neurobiol Dis 2023; 176:105946. [PMID: 36481434 DOI: 10.1016/j.nbd.2022.105946] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 11/29/2022] [Accepted: 12/03/2022] [Indexed: 12/12/2022] Open
Abstract
Migraine is a widespread and debilitating neurological condition affecting more than a billion people worldwide. Thus, more effective migraine therapies are highly needed. In the last decade, two endogenous neuropeptides, calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase-activating peptide (PACAP), were identified to be implicated in migraine. Recently, introduction of monoclonal antibodies (mAbs) blocking the CGRP is the most important advance in migraine therapy for decades. However, 40% of patients are unresponsive to these new drugs. We believe that PACAP may be involved in these patients. Like CGRP, PACAP is located to sensory nerve fibers, it dilates cranial arteries, it causes migraine when infused into patients and it is a peptide that lends itself to antibody therapy. Also, recent studies suggest that the PACAP pathway is independent of the CGRP pathway. Understanding the signaling pathways of PACAP may therefore lead to identification of novel therapeutic targets of particular interest in patients unresponsive to anti-CGRP therapy. Accordingly, neutralizing mAb to PACAP is currently in clinical phase II development. The aim of the present review is, therefore, to give a thorough account of the existing data on PACAP, its receptors and its relation to migraine.
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Affiliation(s)
- Song Guo
- Department of Neurology, Danish Headache Center, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Inger Jansen-Olesen
- Department of Neurology, Danish Headache Center, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Jes Olesen
- Department of Neurology, Danish Headache Center, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Sarah Louise Christensen
- Department of Neurology, Danish Headache Center, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark.
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5
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Alexander TI, Tasma Z, Siow A, Rees TA, Brimble MA, Harris PWR, Hay DL, Walker CS. Novel Fluorescently Labeled PACAP and VIP Highlight Differences between Peptide Internalization and Receptor Pharmacology. ACS Pharmacol Transl Sci 2022; 6:52-64. [PMID: 36654758 PMCID: PMC9841777 DOI: 10.1021/acsptsci.2c00124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Indexed: 12/13/2022]
Abstract
The related peptides pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) have diverse biological functions in peripheral tissues and the central nervous system. Therefore, these peptides and their three receptors represent potential drug targets for several conditions, including neurological and pain-related disorders. However, very little is known about how these peptides regulate their receptors through processes such as internalization. Therefore, we developed tools to study receptor regulation through the synthesis of fluorescently labeled analogues of PACAP-38, PACAP-27, and VIP using copper-mediated 1,3-dipolar cycloaddition of the Cy5 fluorophore. The functionality of Cy5-labeled peptides at their receptors was confirmed in cAMP accumulation assays. Internalization of the Cy5-labeled peptides was then examined and quantified at two distinct PAC1 receptor splice variants, VPAC1 and VPAC2 receptors in transfected cells. All labeled peptides were functional, exhibiting comparable cAMP pharmacology to their unlabeled counterparts and underwent internalization in a time-dependent manner. Temporal differences in the internalization profiles were observed between Cy5-labeled peptides at the PAC1n, PAC1s, VPAC1, and VPAC2 receptors. Interestingly, the pattern of Cy5-labeled peptide activity differed for cAMP accumulation and internalization, indicating that these peptides differentially stimulate cAMP accumulation and internalization and therefore display biased agonism. This novel insight into PACAP-responsive receptor signaling and internalization may provide a unique avenue for future therapeutic development. The fluorescently labeled PACAP and VIP peptides described herein, which we validated as tools to study receptor internalization, will have utility across a broad range of applications and provide greater insight into this receptor family.
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Affiliation(s)
- Tyla I. Alexander
- Department
of Pharmacology and Toxicology, The University
of Otago, Dunedin 9054, New Zealand,Maurice
Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand
| | - Zoe Tasma
- Maurice
Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand,School
of Biological Sciences, The University of
Auckland, Auckland 1010, New Zealand
| | - Andrew Siow
- School
of Chemical Sciences, The University of
Auckland, Auckland 1010, New Zealand
| | - Tayla A. Rees
- Maurice
Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand,School
of Biological Sciences, The University of
Auckland, Auckland 1010, New Zealand
| | - Margaret A. Brimble
- Maurice
Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand,School
of Chemical Sciences, The University of
Auckland, Auckland 1010, New Zealand
| | - Paul W. R. Harris
- Maurice
Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand,School
of Chemical Sciences, The University of
Auckland, Auckland 1010, New Zealand
| | - Debbie L. Hay
- Department
of Pharmacology and Toxicology, The University
of Otago, Dunedin 9054, New Zealand,Maurice
Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand
| | - Christopher S. Walker
- Maurice
Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand,School
of Biological Sciences, The University of
Auckland, Auckland 1010, New Zealand,
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6
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Tasma Z, Siow A, Harris PWR, Brimble MA, O’Carroll SJ, Hay DL, Walker CS. PAC 1, VPAC 1, and VPAC 2 Receptor Expression in Rat and Human Trigeminal Ganglia: Characterization of PACAP-Responsive Receptor Antibodies. Int J Mol Sci 2022; 23:ijms232213797. [PMID: 36430275 PMCID: PMC9697343 DOI: 10.3390/ijms232213797] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/02/2022] [Accepted: 11/06/2022] [Indexed: 11/11/2022] Open
Abstract
Pituitary adenylate cyclase-activating peptide (PACAP) is a neuropeptide expressed in the trigeminal ganglia (TG). The TG conducts nociceptive signals in the head and may play roles in migraine. PACAP infusion provokes headaches in healthy individuals and migraine-like attacks in patients; however, it is not clear whether targeting this system could be therapeutically efficacious. To effectively target the PACAP system, an understanding of PACAP receptor distribution is required. Therefore, this study aimed to characterize commercially available antibodies and use these to detect PACAP-responsive receptors in the TG. Antibodies were initially validated in receptor transfected cell models and then used to explore receptor expression in rat and human TG. Antibodies were identified that could detect PACAP-responsive receptors, including the first antibody to differentiate between the PAC1n and PAC1s receptor splice variants. PAC1, VPAC1, and VPAC2 receptor-like immunoreactivity were observed in subpopulations of both neuronal and glial-like cells in the TG. In this study, PAC1, VPAC1, and VPAC2 receptors were detected in the TG, suggesting they are all potential targets to treat migraine. These antibodies may be useful tools to help elucidate PACAP-responsive receptor expression in tissues. However, most antibodies exhibited limitations, requiring the use of multiple methodologies and the careful inclusion of controls.
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Affiliation(s)
- Zoe Tasma
- School of Biological Sciences, The University of Auckland, Auckland 1010, New Zealand
| | - Andrew Siow
- School of Biological Sciences, The University of Auckland, Auckland 1010, New Zealand
- School of Chemical Sciences, The University of Auckland, Auckland 1010, New Zealand
| | - Paul W. R. Harris
- School of Biological Sciences, The University of Auckland, Auckland 1010, New Zealand
- School of Chemical Sciences, The University of Auckland, Auckland 1010, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand
| | - Margaret A. Brimble
- School of Biological Sciences, The University of Auckland, Auckland 1010, New Zealand
- School of Chemical Sciences, The University of Auckland, Auckland 1010, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand
| | - Simon J. O’Carroll
- Department of Anatomy and Medical Imaging, and Centre for Brain Research, Faculty of Medical and Health Science, The University of Auckland, Auckland 1023, New Zealand
| | - Debbie L. Hay
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand
- Department of Pharmacology and Toxicology, The University of Otago, Dunedin 9016, New Zealand
| | - Christopher S. Walker
- School of Biological Sciences, The University of Auckland, Auckland 1010, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand
- Correspondence:
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7
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PACAP-38 Induces Transcriptomic Changes in Rat Trigeminal Ganglion Cells Related to Neuroinflammation and Altered Mitochondrial Function Presumably via PAC1/VPAC2 Receptor-Independent Mechanism. Int J Mol Sci 2022; 23:ijms23042120. [PMID: 35216232 PMCID: PMC8874739 DOI: 10.3390/ijms23042120] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 11/17/2022] Open
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a broadly expressed neuropeptide which has diverse effects in both the peripheral and central nervous systems. While its neuroprotective effects have been shown in a variety of disease models, both animal and human data support the role of PACAP in migraine generation. Both PACAP and its truncated derivative PACAP(6-38) increased calcium influx in rat trigeminal ganglia (TG) primary sensory neurons in most experimental settings. PACAP(6-38), however, has been described as an antagonist for PACAP type I (known as PAC1), and Vasoactive Intestinal Polypeptide Receptor 2 (also known as VPAC2) receptors. Here, we aimed to compare the signaling pathways induced by the two peptides using transcriptomic analysis. Rat trigeminal ganglion cell cultures were incubated with 1 µM PACAP-38 or PACAP(6-38). Six hours later RNA was isolated, next-generation RNA sequencing was performed and transcriptomic changes were analyzed to identify differentially expressed genes. Functional analysis was performed for gene annotation using the Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome databases. We found 200 common differentially expressed (DE) genes for these two neuropeptides. Both PACAP-38 and PACAP(6-38) treatments caused significant downregulation of NADH: ubiquinone oxidoreductase subunit B6 and upregulation of transient receptor potential cation channel, subfamily M, member 8. The common signaling pathways induced by both peptides indicate that they act on the same target, suggesting that PACAP activates trigeminal primary sensory neurons via a mechanism independent of the identified and cloned PAC1/VPAC2 receptor, either via another target structure or a different splice variant of PAC1/VPAC2 receptors. Identification of the target could help to understand key mechanisms of migraine.
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8
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OUP accepted manuscript. Brain 2022; 145:2450-2460. [DOI: 10.1093/brain/awac040] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 12/07/2021] [Accepted: 01/09/2021] [Indexed: 11/14/2022] Open
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9
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Tasma Z, Siow A, Harris PWR, Brimble MA, Hay DL, Walker CS. Characterisation of agonist signalling profiles and agonist-dependent antagonism at PACAP-responsive receptors: Implications for drug discovery. Br J Pharmacol 2021; 179:435-453. [PMID: 34612509 DOI: 10.1111/bph.15700] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 08/16/2021] [Accepted: 08/30/2021] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND AND PURPOSE The pituitary adenylate cyclase-activating peptide (PACAP) family is of clinical interest for the treatment of migraine. These peptides activate three different PACAP-responsive class B G protein-coupled receptors: the PAC1 , VPAC1 and VPAC2 receptors. The PAC1 receptor may be alternatively spliced, generating variants that can differ in their pharmacological or signalling profiles. To inform drug discovery efforts targeting migraine, we need to better understand how the different PACAP-responsive receptors signal and how effectively these responses can be blocked by antagonists. EXPERIMENTAL APPROACH The signalling profiles of the human PAC1n , PAC1s , VPAC1 and VPAC2 receptors were examined in transfected Cos7 cells for cAMP, IP1 , pAkt, pERK and pCREB. Biased signalling was then quantified. The ability of antagonists to block PACAP-38, PACAP-27 or VIP stimulated cAMP accumulation at PACAP-responsive receptors was also determined. KEY RESULTS PACAP-responsive receptors exhibited varied pharmacological profiles but activated signalling in a similar manner. The PAC1n and PAC1s receptors displayed distinct pharmacology. At the PAC1s receptor, VIP and PHM were more potent than at the PAC1n receptor. PACAP-responsive receptors displayed agonist-dependent antagonism where PACAP-38 was less effectively antagonised compared to PACAP-27 and VIP. CONCLUSIONS AND IMPLICATIONS The distinct pharmacological profile displayed by the PAC1s receptor suggests that it can act as a dual receptor for VIP and PACAP. Furthermore, the effectiveness of blocking a signalling pathway can be influenced by which endogenous PACAP family agonist is present. These effects have potential implications for the development and effectiveness of drugs targeting the PACAP system.
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Affiliation(s)
- Zoe Tasma
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Andrew Siow
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | - Paul W R Harris
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,School of Chemical Sciences, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre and Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Margaret A Brimble
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,School of Chemical Sciences, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre and Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Debbie L Hay
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre and Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.,Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand
| | - Christopher S Walker
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre and Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
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10
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Tasma Z, Wills P, Hay DL, Walker CS. Agonist bias and agonist-dependent antagonism at corticotrophin releasing factor receptors. Pharmacol Res Perspect 2021; 8:e00595. [PMID: 32529807 PMCID: PMC7290078 DOI: 10.1002/prp2.595] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 03/26/2020] [Indexed: 01/14/2023] Open
Abstract
The corticotropin-releasing factor (CRF) receptors represent potential drug targets for the treatment of anxiety, stress, and other disorders. However, it is not known if endogenous CRF receptor agonists display biased signaling, how effective CRF receptor antagonists are at blocking different agonists and signaling pathways or how receptor activity-modifying proteins (RAMPs) effect these processes. This study aimed to address this by investigating agonist and antagonist action at CRF1 and CRF2 receptors. We used CRF1 and CRF2 receptor transfected Cos7 cells to assess the ability of CRF and urocortin (UCN) peptides to activate cAMP, inositol monophosphate (IP1 ), and extracellular signal-regulated kinase 1/2 signaling and determined the ability of antagonists to block agonist-stimulated cAMP and IP1 accumulation. The ability of RAMPs to interact with CRF receptors was also examined. At the CRF1 receptor, CRF and UCN1 activated signaling in the same manner. However, at the CRF2 receptor, UCN1 and UCN2 displayed similar signaling profiles, whereas CRF and UCN3 displayed bias away from IP1 accumulation over cAMP. The antagonist potency was dependent on the receptor, agonist, and signaling pathway. CRF1 and CRF2 receptors had no effect on RAMP1 or RAMP2 surface expression. The presence of biased agonism and agonist-dependent antagonism at the CRF receptors offers new avenues for developing drugs tailored to activate a specific signaling pathway or block a specific agonist. Our findings suggest that the already complex CRF receptor pharmacology may be underappreciated and requires further investigation.
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Affiliation(s)
- Zoe Tasma
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Peter Wills
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Debbie L Hay
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Christopher S Walker
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre and Centre for Brain Research, University of Auckland, Auckland, New Zealand
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11
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Ghanizada H, Al-Karagholi MAM, Arngrim N, Ghanizada M, Larsson HBW, Amin FM, Ashina M. Effect of pituitary adenylate cyclase-activating polypeptide-27 on cerebral hemodynamics in healthy volunteers: A 3T MRI study. Peptides 2019; 121:170134. [PMID: 31449829 DOI: 10.1016/j.peptides.2019.170134] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 08/16/2019] [Accepted: 08/22/2019] [Indexed: 11/17/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) has emerged as an important signaling peptide in migraine pathogenesis. Recently, we have shown that the less-abundant PACAP isoform, PACAP27, induced migraine and headache in patients equipotently to PACAP38. The present study examined the effect of PACAP27 on cerebral hemodynamics in healthy volunteers using high resolution magnetic resonance angiography (MRA). Eighteen healthy volunteers received infusion of PACAP27 (10 pmol/kg/min) or placebo over 20 min and were scanned repeatedly in fixed intervals for 5 h in a double-blind, randomized, placebo-controlled study. The circumference of extra-intracerebral arteries was measured and compared with PACAP38 data. We found significant dilation of middle meningeal artery (MMA) (p = 0.019), superficial temporal artery (p = 0.001) and external carotid artery (p = 0.039) after PACAP27 infusion compared to placebo. Whereas the middle cerebral artery (MCA) (p = 0.011) and internal carotid artery (ICA) (pICAcervical = 0.015, pICAcerebral = 0.019) were constricted. No effects on basilar artery (p = 0.708) and cavernous portion of ICA were found. Post hoc analyses revealed significant larger area under the curve for MMA after PACAP38 compared to PACAP27 (p = 0.033). We also found that PACAP27 induced headache in nine out of twelve (75%) volunteers and one (17%) after placebo. In conclusion, PACAP27 induced headache and dilated extracerebral arteries (>5 h) and slightly constricted MCA in healthy volunteers. Post hoc analysis of PACAP38 data compared with PACAP27 showed that PACAP isoforms dilates MMA with significantly different magnitude.
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Affiliation(s)
- Hashmat Ghanizada
- Danish Headache Center and Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Mohammad Al-Mahdi Al-Karagholi
- Danish Headache Center and Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Nanna Arngrim
- Danish Headache Center and Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Mustafa Ghanizada
- Danish Headache Center and Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Henrik Bo Wiberg Larsson
- Functional Imaging Unit, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Faisal Mohammad Amin
- Danish Headache Center and Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Messoud Ashina
- Danish Headache Center and Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
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Ghanizada H, Al-Karagholi MAM, Arngrim N, Olesen J, Ashina M. PACAP27 induces migraine-like attacks in migraine patients. Cephalalgia 2019; 40:57-67. [DOI: 10.1177/0333102419864507] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Introduction Pituitary adenylate cyclase-activating polypeptide (PACAP) is found in two functional isoforms, namely PACAP38 and PACAP27. The migraine-inducing properties of PACAP38 are well studied. However, it is not known whether the lesser-known and under-studied protein isoform, PACAP27, can also induce migraine attacks. Here, we studied the effect of human PACAP27 infusion on induction of migraine in a provocation model. Methods In a crossover study, 20 migraine without aura patients were randomly assigned to receive human PACAP27 (10 picomol/kg/min) or saline (placebo) infusion over 20 min. We recorded the migraine and associated symptoms. Results All patients completed the study. PACAP27 provoked migraine-like attacks in 11 patients (55%) and two developed attacks after placebo (10%) ( p = 0.022). The headache intensity and duration after PACAP27 was significantly greater compared to placebo ( p = 0.003). Conclusion PACAP27 triggers migraine attacks without aura. These novel data strengthen the role of PACAP and its receptors in migraine pathogenesis.
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Affiliation(s)
- Hashmat Ghanizada
- Danish Headache Center and Department of Neurology, Rigshospitalet-Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
| | - Mohammad Al-Mahdi Al-Karagholi
- Danish Headache Center and Department of Neurology, Rigshospitalet-Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
| | - Nanna Arngrim
- Danish Headache Center and Department of Neurology, Rigshospitalet-Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
| | - Jes Olesen
- Danish Headache Center and Department of Neurology, Rigshospitalet-Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
| | - Messoud Ashina
- Danish Headache Center and Department of Neurology, Rigshospitalet-Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
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13
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Frederiksen SD, Haanes KA, Warfvinge K, Edvinsson L. Perivascular neurotransmitters: Regulation of cerebral blood flow and role in primary headaches. J Cereb Blood Flow Metab 2019; 39:610-632. [PMID: 29251523 PMCID: PMC6446417 DOI: 10.1177/0271678x17747188] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 11/04/2017] [Accepted: 11/06/2017] [Indexed: 12/17/2022]
Abstract
In order to understand the nature of the relationship between cerebral blood flow (CBF) and primary headaches, we have conducted a literature review with particular emphasis on the role of perivascular neurotransmitters. Primary headaches are in general considered complex polygenic disorders (genetic and environmental influence) with pathophysiological neurovascular alterations. Identified candidate headache genes are associated with neuro- and gliogenesis, vascular development and diseases, and regulation of vascular tone. These findings support a role for the vasculature in primary headache disorders. Moreover, neuronal hyperexcitability and other abnormalities have been observed in primary headaches and related to changes in hemodynamic factors. In particular, this relates to migraine aura and spreading depression. During headache attacks, ganglia such as trigeminal and sphenopalatine (located outside the blood-brain barrier) are variably activated and sensitized which gives rise to vasoactive neurotransmitter release. Sympathetic, parasympathetic and sensory nerves to the cerebral vasculature are activated. During migraine attacks, altered CBF has been observed in brain regions such as the somatosensory cortex, brainstem and thalamus. In regulation of CBF, the individual roles of neurotransmitters are partly known, but much needs to be unraveled with respect to headache disorders.
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Affiliation(s)
- Simona D Frederiksen
- Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet Glostrup, Glostrup, Denmark
| | - Kristian A Haanes
- Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet Glostrup, Glostrup, Denmark
| | - Karin Warfvinge
- Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet Glostrup, Glostrup, Denmark
- Division of Experimental Vascular Research, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Lars Edvinsson
- Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet Glostrup, Glostrup, Denmark
- Division of Experimental Vascular Research, Department of Clinical Sciences, Lund University, Lund, Sweden
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15
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Moldovan Loomis C, Dutzar B, Ojala EW, Hendrix L, Karasek C, Scalley-Kim M, Mulligan J, Fan P, Billgren J, Rubin V, Boshaw H, Kwon G, Marzolf S, Stewart E, Jurchen D, Pederson SM, Perrino McCulloch L, Baker B, Cady RK, Latham JA, Allison D, Garcia-Martinez LF. Pharmacologic Characterization of ALD1910, a Potent Humanized Monoclonal Antibody against the Pituitary Adenylate Cyclase-Activating Peptide. J Pharmacol Exp Ther 2019; 369:26-36. [PMID: 30643015 DOI: 10.1124/jpet.118.253443] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 12/27/2018] [Indexed: 01/10/2023] Open
Abstract
Migraine is a debilitating disease that affects almost 15% of the population worldwide and is the first cause of disability in people under 50 years of age, yet its etiology and pathophysiology remain incompletely understood. Recently, small molecules and therapeutic antibodies that block the calcitonin gene-related peptide (CGRP) signaling pathway have reduced migraine occurrence and aborted acute attacks of migraine in clinical trials and provided prevention in patients with episodic and chronic migraine. Heterogeneity is present within each diagnosis and patient's response to treatment, suggesting migraine as a final common pathway potentially activated by multiple mechanisms, e.g., not all migraine attacks respond to or are prevented by anti-CGRP pharmacological interventions. Consequently, other unique mechanisms central to migraine pathogenesis may present new targets for drug development. Pituitary adenylate cyclase-activating peptide (PACAP) is an attractive novel target for treatment of migraines. We generated a specific, high-affinity, neutralizing monoclonal antibody (ALD1910) with reactivity to both PACAP38 and PACAP27. In vitro, ALD1910 effectively antagonizes PACAP38 signaling through the pituitary adenylate cyclase-activating peptide type I receptor, vasoactive intestinal peptide receptor 1, and vasoactive intestinal peptide receptor 2. ALD1910 recognizes a nonlinear epitope within PACAP and blocks its binding to the cell surface. To test ALD1910 antagonistic properties directed against endogenous PACAP, we developed an umbellulone-induced rat model of neurogenic vasodilation and parasympathetic lacrimation. In vivo, this model demonstrates that the antagonistic activity of ALD1910 is dose-dependent, retaining efficacy at doses as low as 0.3 mg/kg. These results indicate that ALD1910 represents a potential therapeutic antibody to address PACAP-mediated migraine.
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Affiliation(s)
| | | | | | - Lee Hendrix
- Alder BioPharmaceuticals, Inc., Bothell, Washington
| | | | | | | | - Pei Fan
- Alder BioPharmaceuticals, Inc., Bothell, Washington
| | | | | | - Heidi Boshaw
- Alder BioPharmaceuticals, Inc., Bothell, Washington
| | - Gayle Kwon
- Alder BioPharmaceuticals, Inc., Bothell, Washington
| | - Sam Marzolf
- Alder BioPharmaceuticals, Inc., Bothell, Washington
| | | | | | | | | | - Brian Baker
- Alder BioPharmaceuticals, Inc., Bothell, Washington
| | - Roger K Cady
- Alder BioPharmaceuticals, Inc., Bothell, Washington
| | | | - Dan Allison
- Alder BioPharmaceuticals, Inc., Bothell, Washington
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16
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Abstract
LINKED ARTICLES This article is part of a themed section on Molecular Pharmacology of GPCRs. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.21/issuetoc.
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Affiliation(s)
- Christopher J Langmead
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityParkvilleVictoriaAustralia
| | - Roger J Summers
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityParkvilleVictoriaAustralia
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17
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Poujol de Molliens M, Létourneau M, Devost D, Hébert TE, Fournier A, Chatenet D. New insights about the peculiar role of the 28–38 C-terminal segment and some selected residues in PACAP for signaling and neuroprotection. Biochem Pharmacol 2018; 154:193-202. [DOI: 10.1016/j.bcp.2018.04.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 04/24/2018] [Indexed: 12/20/2022]
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18
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Bower RL, Yule L, Rees TA, Deganutti G, Hendrikse ER, Harris PWR, Kowalczyk R, Ridgway Z, Wong AG, Swierkula K, Raleigh DP, Pioszak AA, Brimble MA, Reynolds CA, Walker CS, Hay DL. Molecular Signature for Receptor Engagement in the Metabolic Peptide Hormone Amylin. ACS Pharmacol Transl Sci 2018; 1:32-49. [PMID: 32219203 DOI: 10.1021/acsptsci.8b00002] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Indexed: 11/30/2022]
Abstract
The pancreatic peptide hormone, amylin, plays a critical role in the control of appetite, and synergizes with other key metabolic hormones such as glucagon-like peptide 1 (GLP-1). There is opportunity to develop potent and long-acting analogues of amylin or hybrids between these and GLP-1 mimetics for treating obesity. To achieve this, interrogation of how the 37 amino acid amylin peptide engages with its complex receptor system is required. We synthesized an extensive library of peptides to profile the human amylin sequence, determining the role of its disulfide loop, amidated C-terminus and receptor "capture" and "activation" regions in receptor signaling. We profiled four signaling pathways with different ligands at multiple receptor subtypes, in addition to exploring selectivity determinants between related receptors. Distinct roles for peptide subregions in receptor binding and activation were identified, resulting in peptides with greater activity than the native sequence. Enhanced peptide activity was preserved in the brainstem, the major biological target for amylin. Interpretation of our data using full-length active receptor models supported by molecular dynamics, metadynamics, and supervised molecular dynamics simulations guided the synthesis of a potent dual agonist of GLP-1 and amylin receptors. The data offer new insights into the function of peptide amidation, how allostery drives peptide-receptor interactions, and provide a valuable resource for the development of novel amylin agonists for treating diabetes and obesity.
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Affiliation(s)
- Rebekah L Bower
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Lauren Yule
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Tayla A Rees
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Giuseppe Deganutti
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, U.K
| | - Erica R Hendrikse
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Paul W R Harris
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Renata Kowalczyk
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Zachary Ridgway
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Amy G Wong
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Katarzyna Swierkula
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, U.K
| | - Daniel P Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States.,Department of Structural and Molecular Biology, University College London, London WC1E 6BT, U.K
| | - Augen A Pioszak
- Department of Biochemistry and Molecular Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, United States
| | - Margaret A Brimble
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Christopher A Reynolds
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, U.K
| | - Christopher S Walker
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Debbie L Hay
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
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19
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Abstract
The hypothalamus is involved in the regulation of homeostatic mechanisms and migraine-related trigeminal nociception and as such has been hypothesized to play a central role in the migraine syndrome from the earliest stages of the attack. The hypothalamus hosts many key neuropeptide systems that have been postulated to play a role in this pathophysiology. Such neuropeptides include but are not exclusive too orexins, oxytocin, neuropeptide Y, and pituitary adenylate cyclase activating protein, which will be the focus of this review. Each of these peptides has its own unique physiological role and as such many preclinical studies have been conducted targeting these peptide systems with evidence supporting their role in migraine pathophysiology. Preclinical studies have also begun to explore potential therapeutic compounds targeting these systems with some success in all cases. Clinical efficacy of dual orexin receptor antagonists and intranasal oxytocin have been tested; however, both have yet to demonstrate clinical effect. Despite this, there were limitations in these cases and strong arguments can be made for the further development of intranasal oxytocin for migraine prophylaxis. Regarding neuropeptide Y, work has yet to begun in a clinical setting, and clinical trials for pituitary adenylate cyclase activating protein are just beginning to be established with much optimism. Regardless, it is becoming increasingly clear the prominent role that the hypothalamus and its peptide systems have in migraine pathophysiology. Much work is required to better understand this system and the early stages of the attack to develop more targeted and effective therapies aimed at reducing attack susceptibility with the potential to prevent the attack all together.
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Affiliation(s)
- Lauren C Strother
- Headache Group, Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
| | - Anan Srikiatkhachorn
- International Medical College, King Mongkut's Institute of Technology Ladkrabang, Bangkok, Thailand
| | - Weera Supronsinchai
- Department of Physiology, Faculty of Dentistry, Chulalongkorn University, Pathumwan, Bangkok, Thailand.
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20
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PENG Y, XU M, HUANG G, ZHANG H, AI K. Effect of electroacupuncture on urodynamics, PACAP-38 and PAC1R of spinal cord in rats with neurogenic bladder ✰. WORLD JOURNAL OF ACUPUNCTURE-MOXIBUSTION 2018. [DOI: 10.1016/j.wjam.2018.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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21
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Sundrum T, Walker CS. Pituitary adenylate cyclase-activating polypeptide receptors in the trigeminovascular system: implications for migraine. Br J Pharmacol 2017; 175:4109-4120. [PMID: 28977676 DOI: 10.1111/bph.14053] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 08/24/2017] [Accepted: 09/11/2017] [Indexed: 12/13/2022] Open
Abstract
The neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) has been implicated in a wide range of functions including vasodilatation, neuroprotection, nociception and neurogenic inflammation. PACAP activates three distinct receptors, the PAC1 receptor, which responds to PACAP, and the VPAC1 and VPAC2 receptors, which respond to both PACAP and vasoactive intestinal polypeptide. The trigeminovascular system plays a key role in migraine and contains the trigeminal nerve, which is the major conduit of craniofacial pain. PACAP is expressed throughout the trigeminovascular system and in higher brain regions involved in processing pain. Evidence from human clinical studies suggests that PACAP may act outside the blood-brain barrier in the pathogenesis of migraine. However, the precise mechanisms involved remain unclear. PACAP potentially induces migraine attacks by activating different receptors in different cell types and tissues. This complexity prompted this review of PACAP receptor pharmacology, expression and function in the trigeminovascular system. Current evidence suggests that the PAC1 receptor is the likely pathophysiological target of PACAP in migraine. However, multiple PACAP receptors are expressed in key parts of the trigeminovascular system and further work is required to determine their contribution to PACAP physiology and the pathology of migraine. LINKED ARTICLES This article is part of a themed section on Molecular Pharmacology of GPCRs. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.21/issuetoc.
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Affiliation(s)
- Tahlia Sundrum
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Christopher S Walker
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre and Centre for Brain Research, University of Auckland, Auckland, New Zealand
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22
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Bohn KJ, Li B, Huang X, Mason BN, Wattiez AS, Kuburas A, Walker CS, Yang P, Yu J, Heinz BA, Johnson KW, Russo AF. CGRP receptor activity in mice with global expression of human receptor activity modifying protein 1. Br J Pharmacol 2017; 174:1826-1840. [PMID: 28317098 DOI: 10.1111/bph.13783] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 01/26/2017] [Accepted: 03/03/2017] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND AND PURPOSE CGRP is a potent vasodilator and nociceptive neuropeptide linked to migraine. CGRP receptors are heterodimers of receptor activity modifying protein 1 (RAMP1) and either calcitonin receptor-like receptor (CLR; forms canonical CGRP receptor) or calcitonin receptor (CT receptor; forms AMY1 receptor). The goal of this study was to test whether transgenic mice globally expressing human RAMP1 have increased CGRP receptor activity and whether the receptors are sensitive to human selective antagonist telcagepant. EXPERIMENTAL APPROACH cAMP production was measured in primary cultures of aortic smooth muscle and trigeminal ganglia neurons from global hRAMP1 mice and non-transgenic littermates. Functional activity and inhibition were compared with clonal cell lines expressing combinations of CLR or CT receptors with RAMP1. KEY RESULTS Cultured smooth muscle from global hRAMP1 mice had a 10-fold greater CGRP-induced cAMP maximal response (Rmax) than non-transgenic littermates, with similar EC50 s. In contrast, cultured trigeminal ganglia from global hRAMP1 mice had a 40-fold leftward shift of the EC50 , with similar Rmax values as littermates. In both hRAMP1 cultures, telcagepant blocked CGRP-induced cAMP production, but was not effective in non-transgenic cultures. IC50 values were closer to those observed for CT receptor/hRAMP1 than CLR/hRAMP1 in clonal cell lines. CONCLUSIONS AND IMPLICATIONS Overexpression of hRAMP1 increases CGRP signalling by changing the maximal response or ligand sensitivity, depending on tissue type. Furthermore, telcagepant inhibited transgenic hRAMP1 CGRP receptors, but the degree of inhibition suggests that the transgenic mice are only partially humanized or both canonical CGRP and AMY1 receptors are functional in trigeminal ganglia neurons and vascular smooth muscle.
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Affiliation(s)
- Keegan J Bohn
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, USA
| | - Baolin Li
- Neuroscience Research Division, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Xiaofang Huang
- Neuroscience Research Division, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Bianca N Mason
- Molecular and Cellular Biology Program, University of Iowa, Iowa City, IA, USA
| | - Anne-Sophie Wattiez
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, USA
| | - Adisa Kuburas
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, USA
| | - Christopher S Walker
- Maurice Wilkins Centre and Centre for Brain Research, School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Peiyi Yang
- Quantitative Biology, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Jianliang Yu
- Quantitative Biology, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Beverly A Heinz
- Quantitative Biology, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Kirk W Johnson
- Neuroscience Research Division, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Andrew F Russo
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, USA.,Department of Neurology, University of Iowa, Iowa City, IA, USA.,Molecular and Cellular Biology Program, University of Iowa, Iowa City, IA, USA.,Veterans Affairs Medical Center, Iowa City, IA, USA
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23
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Walker CS, Raddant AC, Woolley MJ, Russo AF, Hay DL. CGRP receptor antagonist activity of olcegepant depends on the signalling pathway measured. Cephalalgia 2017; 38:437-451. [PMID: 28165287 DOI: 10.1177/0333102417691762] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background Calcitonin gene-related peptide (CGRP) is a neuropeptide that acts in the trigeminovascular system and is believed to play an important role in migraine. CGRP activates two receptors that are both present in the trigeminovascular system; the CGRP receptor and the amylin 1 (AMY1) receptor. CGRP receptor antagonists, including olcegepant (BIBN4096BS) and telcagepant (MK-0974), can treat migraine. This study aimed to determine the effectiveness of these antagonists at blocking CGRP receptor signalling in trigeminal ganglia (TG) neurons and transfected CGRP and AMY1 receptors in Cos7 cells, to better understand their mechanism of action. Methods CGRP stimulation of four intracellular signalling molecules relevant to pain (cAMP, CREB, p38 and ERK) were examined in rat TG neurons and compared to transfected CGRP and AMY1 receptors in Cos7 cells. Results In TG neurons, olcegepant displayed signal-specific differences in antagonism of CGRP responses. This effect was also evident in transfected Cos7 cells, where olcegepant blocked CREB phosphorylation more potently than expected at the AMY1 receptor, suggesting that the affinity of this antagonist can be dependent on the signalling pathway activated. Conclusions CGRP receptor antagonist activity appears to be assay-dependent. Thus, these molecules may not be as selective for the CGRP receptor as commonly reported.
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Affiliation(s)
- Christopher S Walker
- 1 School of Biological Sciences, University of Auckland, Auckland, New Zealand.,2 Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Ann C Raddant
- 3 Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, USA
| | - Michael J Woolley
- 4 Institute of Clinical Studies, University of Birmingham, Edgbaston, Birmingham, UK
| | - Andrew F Russo
- 3 Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, USA.,5 Department of Neurology, University of Iowa; Veterans Affairs Medical Center, Iowa City, IA, USA
| | - Debbie L Hay
- 1 School of Biological Sciences, University of Auckland, Auckland, New Zealand.,2 Centre for Brain Research, University of Auckland, Auckland, New Zealand
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24
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Wootten D, Miller LJ, Koole C, Christopoulos A, Sexton PM. Allostery and Biased Agonism at Class B G Protein-Coupled Receptors. Chem Rev 2016; 117:111-138. [PMID: 27040440 DOI: 10.1021/acs.chemrev.6b00049] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Class B G protein-coupled receptors (GPCRs) respond to paracrine or endocrine peptide hormones involved in control of bone homeostasis, glucose regulation, satiety, and gastro-intestinal function, as well as pain transmission. These receptors are targets for existing drugs that treat osteoporosis, hypercalcaemia, Paget's disease, type II diabetes, and obesity and are being actively pursued as targets for numerous other diseases. Exploitation of class B receptors has been limited by difficulties with small molecule drug discovery and development and an under appreciation of factors governing optimal therapeutic efficacy. Recently, there has been increasing awareness of novel attributes of GPCR function that offer new opportunity for drug development. These include the presence of allosteric binding sites on the receptor that can be exploited as drug binding pockets and the ability of individual drugs to enrich subpopulations of receptor conformations to selectively control signaling, a phenomenon termed biased agonism. In this review, current knowledge of biased signaling and small molecule allostery within class B GPCRs is discussed, highlighting areas that have progressed significantly over the past decade, in addition to those that remain largely unexplored with respect to these phenomena.
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Affiliation(s)
- Denise Wootten
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville 3052, Victoria, Australia
| | - Laurence J Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic , Scottsdale, Arizona 85259, United States
| | - Cassandra Koole
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville 3052, Victoria, Australia.,Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University , New York, New York 10065, United States
| | - Arthur Christopoulos
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville 3052, Victoria, Australia
| | - Patrick M Sexton
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville 3052, Victoria, Australia
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25
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Sághy É, Payrits M, Helyes Z, Reglődi D, Bánki E, Tóth G, Couvineau A, Szőke É. Stimulatory effect of pituitary adenylate cyclase-activating polypeptide 6-38, M65 and vasoactive intestinal polypeptide 6-28 on trigeminal sensory neurons. Neuroscience 2015; 308:144-56. [PMID: 26321242 DOI: 10.1016/j.neuroscience.2015.08.043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 07/31/2015] [Accepted: 08/20/2015] [Indexed: 02/08/2023]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) acts on G protein-coupled receptors: the specific PAC1 and VPAC1/VPAC2 receptors. PACAP6-38 was described as a potent PAC1/VPAC2 antagonist in several models, but recent studies reported its agonistic behaviors proposing novel receptorial mechanisms. Since PACAP in migraine is an important research tool, we investigated the effect of PACAP and its peptide fragments on trigeminal primary sensory neurons. Effect of the peptides was studied with ratiometric Ca-imaging technique using the fluorescent indicator fura-2 AM on primary cultures of rat and mouse trigeminal ganglia (TRGs) neurons. Specificity testing was performed on PAC1, VPAC1 and VPAC2 receptor-expressing cell lines with both fluorescent and radioactive Ca-uptake methods. Slowly increasing intracellular free calcium concentration [Ca(2+)]i was detected after PACAP1-38, PACAP1-27, vasoactive intestinal polypeptide (VIP) and the selective PAC1 receptor agonist maxadilan administration on TRG neurons, but interestingly, PACAP6-38, VIP6-28 and the PAC1 receptor antagonist M65 also caused similar activation. The VPAC2 receptor agonist BAY 55-9837 induced similar activation, while the VPAC1 receptor agonist Ala(11,22,28)VIP had no significant effect on [Ca(2+)]i. It was proven that the Ca(2+)-influx originated from intracellular stores using radioactive calcium-45 uptake experiment and Ca-free solution. On the specific receptor-expressing cell lines the antagonists inhibited the stimulating actions of the respective agonists, but had no effects by themselves. PACAP6-38, M65 and VIP6-28, which were described as antagonists in numerous studies in several model systems, act as agonists on TRG primary sensory neurons. Currently unknown receptors or splice variants linked to distinct signal transduction pathways might explain these differences.
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MESH Headings
- Animals
- CHO Cells
- Calcium/metabolism
- Cells, Cultured
- Cricetulus
- Humans
- Insect Proteins/pharmacology
- Mice
- Peptide Fragments/pharmacology
- Pituitary Adenylate Cyclase-Activating Polypeptide/pharmacology
- Rats, Wistar
- Receptors, Vasoactive Intestinal Peptide, Type II/antagonists & inhibitors
- Receptors, Vasoactive Intestinal Peptide, Type II/metabolism
- Receptors, Vasoactive Intestinal Polypeptide, Type I/agonists
- Receptors, Vasoactive Intestinal Polypeptide, Type I/metabolism
- Sensory Receptor Cells/drug effects
- Sensory Receptor Cells/physiology
- Sensory System Agents/pharmacology
- TRPV Cation Channels/metabolism
- Trigeminal Ganglion/drug effects
- Trigeminal Ganglion/physiology
- Vasoactive Intestinal Peptide/pharmacology
- Voltage-Sensitive Dye Imaging
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Affiliation(s)
- É Sághy
- Department of Pharmacology and Pharmacotherapy, MTA-PTE Chronic Pain Research Group, Szentágothai Research Center, University of Pécs, Pécs-7624, Szigeti Street 12, Hungary.
| | - M Payrits
- Department of Pharmacology and Pharmacotherapy, MTA-PTE Chronic Pain Research Group, Szentágothai Research Center, University of Pécs, Pécs-7624, Szigeti Street 12, Hungary.
| | - Zs Helyes
- Department of Pharmacology and Pharmacotherapy, MTA-PTE Chronic Pain Research Group, Szentágothai Research Center, University of Pécs, Pécs-7624, Szigeti Street 12, Hungary.
| | - D Reglődi
- Department of Anatomy, MTA-PTE "Lendület" PACAP Research Team, University of Pécs, Pécs-7624, Szigeti Street 12, Hungary.
| | - E Bánki
- Department of Anatomy, MTA-PTE "Lendület" PACAP Research Team, University of Pécs, Pécs-7624, Szigeti Street 12, Hungary.
| | - G Tóth
- Department of Medical Chemistry, University of Szeged, Szeged-6720, Dugonics Street 13, Hungary.
| | - A Couvineau
- UMR 1149 INSERM/Centre de Recherche sur l'Inflammation, Université Paris Diderot, Faculte de Medecine Paris 7 - Site Bichat, 16 Rue Henri Huchard, 75890 Paris Cedex 18, France.
| | - É Szőke
- Department of Pharmacology and Pharmacotherapy, MTA-PTE Chronic Pain Research Group, Szentágothai Research Center, University of Pécs, Pécs-7624, Szigeti Street 12, Hungary.
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26
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Walker CS, Eftekhari S, Bower RL, Wilderman A, Insel PA, Edvinsson L, Waldvogel HJ, Jamaluddin MA, Russo AF, Hay DL. A second trigeminal CGRP receptor: function and expression of the AMY1 receptor. Ann Clin Transl Neurol 2015; 2:595-608. [PMID: 26125036 PMCID: PMC4479521 DOI: 10.1002/acn3.197] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 03/01/2015] [Accepted: 03/02/2015] [Indexed: 12/14/2022] Open
Abstract
Objective The trigeminovascular system plays a central role in migraine, a condition in need of new treatments. The neuropeptide, calcitonin gene-related peptide (CGRP), is proposed as causative in migraine and is the subject of intensive drug discovery efforts. This study explores the expression and functionality of two CGRP receptor candidates in the sensory trigeminal system. Methods Receptor expression was determined using Taqman G protein-coupled receptor arrays and immunohistochemistry in trigeminal ganglia (TG) and the spinal trigeminal complex of the brainstem in rat and human. Receptor pharmacology was quantified using sensitive signaling assays in primary rat TG neurons. Results mRNA and histological expression analysis in rat and human samples revealed the presence of two CGRP-responsive receptors (AMY1: calcitonin receptor/receptor activity-modifying protein 1 [RAMP1]) and the CGRP receptor (calcitonin receptor-like receptor/RAMP1). In support of this finding, quantification of agonist and antagonist potencies revealed a dual population of functional CGRP-responsive receptors in primary rat TG neurons. Interpretation The unexpected presence of a functional non-canonical CGRP receptor (AMY1) at neural sites important for craniofacial pain has important implications for targeting the CGRP axis in migraine.
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Affiliation(s)
- Christopher S Walker
- School of Biological Sciences, University of Auckland Auckland, 1142, New Zealand ; Centre for Brain Research, University of Auckland Auckland, 1142, New Zealand
| | - Sajedeh Eftekhari
- Division of Experimental Vascular Research, Department of Clinical Sciences, Lund University Lund, Sweden
| | - Rebekah L Bower
- School of Biological Sciences, University of Auckland Auckland, 1142, New Zealand ; Centre for Brain Research, University of Auckland Auckland, 1142, New Zealand
| | - Andrea Wilderman
- Departments of Pharmacology and Medicine, University of California at San Diego La Jolla, California
| | - Paul A Insel
- Departments of Pharmacology and Medicine, University of California at San Diego La Jolla, California
| | - Lars Edvinsson
- Division of Experimental Vascular Research, Department of Clinical Sciences, Lund University Lund, Sweden
| | - Henry J Waldvogel
- Centre for Brain Research, University of Auckland Auckland, 1142, New Zealand ; Department of Anatomy with Radiology, Faculty of Medical and Health Science, University of Auckland Auckland, 1142, New Zealand
| | | | - Andrew F Russo
- Department of Molecular Physiology and Biophysics, University of Iowa Iowa City, Iowa ; Department of Neurology, Veterans Affairs Medical Center, University of Iowa Iowa City, Iowa
| | - Debbie L Hay
- School of Biological Sciences, University of Auckland Auckland, 1142, New Zealand ; Centre for Brain Research, University of Auckland Auckland, 1142, New Zealand
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27
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Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Signalling Enhances Osteogenesis in UMR-106 Cell Line. J Mol Neurosci 2014; 54:555-73. [DOI: 10.1007/s12031-014-0389-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 07/22/2014] [Indexed: 01/14/2023]
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28
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Edvinsson L. PACAP and its receptors in migraine pathophysiology: Commentary on Walker et al., Br J Pharmacol 171: 1521-1533. Br J Pharmacol 2014; 172:4782-4. [PMID: 24826981 DOI: 10.1111/bph.12772] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Revised: 04/25/2014] [Accepted: 04/30/2014] [Indexed: 11/28/2022] Open
Affiliation(s)
- Lars Edvinsson
- Department of Medicine, Institute of Clinical Sciences, Lund University, Sweden
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29
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Investigation of PACAP Fragments and Related Peptides in Chronic Retinal Hypoperfusion. J Ophthalmol 2014; 2014:563812. [PMID: 24900914 PMCID: PMC4036611 DOI: 10.1155/2014/563812] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 03/24/2014] [Indexed: 12/05/2022] Open
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) has neuroprotective effects in different neuronal and retinal injuries. Retinal ischemia can be effectively modelled by permanent bilateral common carotid artery occlusion (BCCAO), which causes chronic hypoperfusion-induced degeneration in the entire rat retina. The retinoprotective effect of PACAP 1-38 and VIP is well-established in ischemic retinopathy. However, little is known about the effects of related peptides and PACAP fragments in ischemic retinopathy. The aim of the present study was to investigate the potential retinoprotective effects of different PACAP fragments (PACAP 4-13, 4-22, 6-10, 6-15, 11-15, and 20-31) and related peptides (secretin, glucagon) in BCCAO-induced ischemic retinopathy. Wistar rats (3-4 months old) were used in the experiment. After performing BCCAO, the right eyes of the animals were treated with PACAP fragments or related peptides intravitreal (100 pM), while the left eyes were injected with saline serving as control eyes. Sham-operated (without BCCAO) rats received the same treatment. Routine histology was performed 2 weeks after the surgery; cells were counted and the thickness of retinal layers was compared. Our results revealed significant neuroprotection by PACAP 1-38 but did not reveal retinoprotective effect of the PACAP fragments or related peptides. These results suggest that PACAP 1-38 has the greatest efficacy in ischemic retinopathy.
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30
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Pituitary adenylate cyclase activating polypeptide (PACAP) signalling exerts chondrogenesis promoting and protecting effects: implication of calcineurin as a downstream target. PLoS One 2014; 9:e91541. [PMID: 24643018 PMCID: PMC3958376 DOI: 10.1371/journal.pone.0091541] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 02/13/2014] [Indexed: 01/20/2023] Open
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is an important neurotrophic factor influencing differentiation of neuronal elements and exerting protecting role during traumatic injuries or inflammatory processes of the central nervous system. Although increasing evidence is available on its presence and protecting function in various peripheral tissues, little is known about the role of PACAP in formation of skeletal components. To this end, we aimed to map elements of PACAP signalling in developing cartilage under physiological conditions and during oxidative stress. mRNAs of PACAP and its receptors (PAC1,VPAC1, VPAC2) were detectable during differentiation of chicken limb bud-derived chondrogenic cells in micromass cell cultures. Expression of PAC1 protein showed a peak on days of final commitment of chondrogenic cells. Administration of either the PAC1 receptor agonist PACAP 1-38, or PACAP 6-38 that is generally used as a PAC1 antagonist, augmented cartilage formation, stimulated cell proliferation and enhanced PAC1 and Sox9 protein expression. Both variants of PACAP elevated the protein expression and activity of the Ca-calmodulin dependent Ser/Thr protein phosphatase calcineurin. Application of PACAPs failed to rescue cartilage formation when the activity of calcineurin was pharmacologically inhibited with cyclosporine A. Moreover, exogenous PACAPs prevented diminishing of cartilage formation and decrease of calcineurin activity during oxidative stress. As an unexpected phenomenon, PACAP 6-38 elicited similar effects to those of PACAP 1-38, although to a different extent. On the basis of the above results, we propose calcineurin as a downstream target of PACAP signalling in differentiating chondrocytes either in normal or pathophysiological conditions. Our observations imply the therapeutical perspective that PACAP can be applied as a natural agent that may have protecting effect during joint inflammation and/or may promote cartilage regeneration during degenerative diseases of articular cartilage.
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