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Ma X, Guo J, Fu Y, Shen C, Jiang P, Zhang Y, Zhang L, Yu Y, Fan J, Chai R. G protein-coupled receptors in cochlea: Potential therapeutic targets for hearing loss. Front Mol Neurosci 2022; 15:1028125. [PMID: 36311029 PMCID: PMC9596917 DOI: 10.3389/fnmol.2022.1028125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 09/21/2022] [Indexed: 11/29/2022] Open
Abstract
The prevalence of hearing loss-related diseases caused by different factors is increasing worldwide year by year. Currently, however, the patient’s hearing loss has not been effectively improved. Therefore, there is an urgent need to adopt new treatment measures and treatment techniques to help improve the therapeutic effect of hearing loss. G protein-coupled receptors (GPCRs), as crucial cell surface receptors, can widely participate in different physiological and pathological processes, particularly play an essential role in many disease occurrences and be served as promising therapeutic targets. However, no specific drugs on the market have been found to target the GPCRs of the cochlea. Interestingly, many recent studies have demonstrated that GPCRs can participate in various pathogenic process related to hearing loss in the cochlea including heredity, noise, ototoxic drugs, cochlear structure, and so on. In this review, we comprehensively summarize the functions of 53 GPCRs known in the cochlea and their relationships with hearing loss, and highlight the recent advances of new techniques used in cochlear study including cryo-EM, AI, GPCR drug screening, gene therapy vectors, and CRISPR editing technology, as well as discuss in depth the future direction of novel GPCR-based drug development and gene therapy for cochlear hearing loss. Collectively, this review is to facilitate basic and (pre-) clinical research in this area, and provide beneficial help for emerging GPCR-based cochlear therapies.
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Affiliation(s)
- Xiangyu Ma
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
| | - Jiamin Guo
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
| | - Yaoyang Fu
- Department of Psychiatry, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Cangsong Shen
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Pei Jiang
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
| | - Yuan Zhang
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China
- Research Institute of Otolaryngology, Nanjing, China
| | - Lei Zhang
- Department of Otorhinolaryngology, Head and Neck Surgery, The Second Hospital of Anhui Medical University, Hefei, China
| | - Yafeng Yu
- First Affiliated Hospital of Soochow University, Soochow, China
- *Correspondence: Yafeng Yu,
| | - Jiangang Fan
- Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Jiangang Fan,
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
- Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
- Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
- Renjie Chai,
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Ruel J, Guitton MJ, Gratias P, Lenoir M, Shen S, Puel JL, Brabet P, Wang J. Endogenous Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Plays a Protective Effect Against Noise-Induced Hearing Loss. Front Cell Neurosci 2021; 15:658990. [PMID: 33828461 PMCID: PMC8019930 DOI: 10.3389/fncel.2021.658990] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/02/2021] [Indexed: 01/07/2023] Open
Abstract
Pituitary adenylyl cyclase-activating polypeptide (PACAP) is a member of the vasoactive intestinal polypeptide (VIP)-the secretin-glucagon family of neuropeptides. They act through two classes of receptors: PACAP type 1 (PAC1) and type 2 (VPAC1 and VPAC2). Among their pleiotropic effects throughout the body, PACAP functions as neuromodulators and neuroprotectors, rescuing neurons from apoptosis, mostly through the PAC1 receptor. To explore the potential protective effect of endogenous PACAP against Noise-induced hearing loss (NIHL), we used a knockout mouse model lacking PAC1 receptor expression (PACR1−/−) and a transgenic humanized mouse model expressing the human PAC1 receptor (TgHPAC1R). Based on complementary approaches combining electrophysiological, histochemical, and molecular biological evaluations, we show PAC1R expression in spiral ganglion neurons and in cochlear apical cells of the organ of Corti. Wild-type (WT), PAC1R−/−, and TgHPAC1R mice exhibit similar auditory thresholds. For most of the frequencies tested after acute noise damage, however, PAC1R−/− mice showed a larger elevation of the auditory threshold than did their WT counterparts. By contrast, in a transgene copy number-dependent fashion, TgHPAC1R mice showed smaller noise-induced elevations of auditory thresholds compared to their WT counterparts. Together, these findings suggest that PACAP could be a candidate for endogenous protection against noise-induced hearing loss.
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Affiliation(s)
- Jérôme Ruel
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France.,Laboratoire de Neurosciences Cognitives, UMR7291 CNRS, Aix-Marseille Université, Marseille, France
| | - Matthieu J Guitton
- CERVO Brain Research Center, Faculty of Medicine, Laval University, Quebec City, QC, Canada
| | - Paul Gratias
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France
| | - Marc Lenoir
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France
| | - Sanbing Shen
- Regenerative Medicine Institute, National University of Ireland (NUI), Galway, Ireland
| | - Jean-Luc Puel
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France
| | - Philippe Brabet
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France
| | - Jing Wang
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France
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3
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Fulop DB, Humli V, Szepesy J, Ott V, Reglodi D, Gaszner B, Nemeth A, Szirmai A, Tamas L, Hashimoto H, Zelles T, Tamas A. Hearing impairment and associated morphological changes in pituitary adenylate cyclase activating polypeptide (PACAP)-deficient mice. Sci Rep 2019; 9:14598. [PMID: 31601840 PMCID: PMC6787024 DOI: 10.1038/s41598-019-50775-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 09/17/2019] [Indexed: 12/18/2022] Open
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a regulatory and cytoprotective neuropeptide, its deficiency implies accelerated aging in mice. It is present in the auditory system having antiapoptotic effects. Expression of Ca2+-binding proteins and its PAC1 receptor differs in the inner ear of PACAP-deficient (KO) and wild-type (WT) mice. Our aim was to elucidate the functional role of PACAP in the auditory system. Auditory brainstem response (ABR) tests found higher hearing thresholds in KO mice at click and low frequency burst stimuli. Hearing impairment at higher frequencies showed as reduced ABR wave amplitudes and latencies in KO animals. Increase in neuronal activity, demonstrated by c-Fos immunolabeling, was lower in KO mice after noise exposure in the ventral and dorsal cochlear nuclei. Noise induced neuronal activation was similar in further relay nuclei of the auditory pathway of WT and KO mice. Based on the similar inflammatory and angiogenic protein profile data from cochlear duct lysates, neither inflammation nor disturbed angiogenesis, as potential pathological components in sensorineural hearing losses, seem to be involved in the pathomechanism of the presented functional and morphological changes in PACAP KO mice. The hearing impairment is probably concomitant with the markedly accelerated aging processes in these animals.
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Affiliation(s)
- Daniel Balazs Fulop
- Department of Anatomy, MTA-PTE PACAP Research Team, Centre for Neuroscience, University of Pecs Medical School, Pecs, Hungary
| | - Viktoria Humli
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Judit Szepesy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Virag Ott
- Department of Anatomy, MTA-PTE PACAP Research Team, Centre for Neuroscience, University of Pecs Medical School, Pecs, Hungary
| | - Dora Reglodi
- Department of Anatomy, MTA-PTE PACAP Research Team, Centre for Neuroscience, University of Pecs Medical School, Pecs, Hungary
| | - Balazs Gaszner
- Department of Anatomy, MTA-PTE PACAP Research Team, Centre for Neuroscience, University of Pecs Medical School, Pecs, Hungary
| | - Adrienn Nemeth
- Department of Anatomy, MTA-PTE PACAP Research Team, Centre for Neuroscience, University of Pecs Medical School, Pecs, Hungary.,Department of Otorhinolaryngology, University of Pecs Medical School, Pecs, Hungary
| | - Agnes Szirmai
- Department of Otorhinolaryngology, Head and Neck Surgery, Semmelweis University, Budapest, Hungary
| | - Laszlo Tamas
- Department of Otorhinolaryngology, Head and Neck Surgery, Semmelweis University, Budapest, Hungary
| | - Hitoshi Hashimoto
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan.,Molecular Research Center for Children's Mental Development, United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Suita, Osaka, Japan.,Division of Bioscience, Institute for Datability Science, Osaka University, Suita, Osaka, Japan
| | - Tibor Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary. .,Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
| | - Andrea Tamas
- Department of Anatomy, MTA-PTE PACAP Research Team, Centre for Neuroscience, University of Pecs Medical School, Pecs, Hungary.
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4
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Kasica N, Podlasz P, Sundvik M, Tamas A, Reglodi D, Kaleczyc J. Protective Effects of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Against Oxidative Stress in Zebrafish Hair Cells. Neurotox Res 2016; 30:633-647. [PMID: 27557978 PMCID: PMC5047952 DOI: 10.1007/s12640-016-9659-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 07/26/2016] [Accepted: 08/09/2016] [Indexed: 12/30/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a pleiotropic neuropeptide, with known antiapoptotic functions. Our previous in vitro study has demonstrated the ameliorative role of PACAP-38 in chicken hair cells under oxidative stress conditions, but its effects on living hair cells is now yet known. Therefore, the aim of the present study was to investigate in vivo the protective role of PACAP-38 in hair cells found in zebrafish (Danio rerio) sense organs-neuromasts. To induce oxidative stress the 5-day postfertilization (dpf) zebrafish larvae were exposed to 1.5 mM H2O2 for 15 min or 1 h. This resulted in an increase in caspase-3 and p-38 MAPK level in the hair cells as well as in an impairment of the larvae basic behavior. To investigate the ameliorative role of PACAP-38, the larvae were incubated with a mixture of 1.5 mM H2O2 and 100 nM PACAP-38 following 1 h preincubation with 100 nM PACAP-38 only. PACAP-38 abilities to prevent hair cells from apoptosis were investigated. Whole-mount immunohistochemistry and confocal microscopy analyses revealed that PACAP-38 treatment decreased the cleaved caspase-3 level in the hair cells, but had no influence on p-38 MAPK. The analyses of basic locomotor activity supported the protective role of PACAP-38 by demonstrating the improvement of the fish behavior after PACAP-38 treatment. In summary, our in vivo findings demonstrate that PACAP-38 protects zebrafish hair cells from oxidative stress by attenuating oxidative stress-induced apoptosis.
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Affiliation(s)
- Natalia Kasica
- Department of Animal Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, box 105J, 10-719, Olsztyn, Poland.
| | - Piotr Podlasz
- Department of Pathophysiology, Forensic Veterinary and Administration, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, 10-719, Olsztyn, Poland
| | - Maria Sundvik
- Department of Anatomy, Neuroscience Center, University of Helsinki, Haartmaninkatu 8 (Biomedicum Helsinki), 00290, Helsinki, Finland
| | - Andrea Tamas
- Department of Anatomy, University of Pecs, Szigeti 12, 7624, Pecs, Hungary
| | - Dora Reglodi
- Department of Anatomy, University of Pecs, Szigeti 12, 7624, Pecs, Hungary
| | - Jerzy Kaleczyc
- Department of Animal Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, box 105J, 10-719, Olsztyn, Poland
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5
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Pituitary Adenylate Cyclase-Activating Polypeptide Is Upregulated in Murine Skin Inflammation and Mediates Transient Receptor Potential Vanilloid-1-Induced Neurogenic Edema. J Invest Dermatol 2015; 135:2209-2218. [PMID: 25905588 DOI: 10.1038/jid.2015.156] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 03/23/2015] [Accepted: 04/08/2015] [Indexed: 12/18/2022]
Abstract
Although pituitary adenylate cyclase-activating polypeptide (PACAP) was described as a key vasoregulator in human skin, little is known about its expression in mouse skin. As it is important to investigate PACAP signaling in translational mouse dermatitis models, we determined its presence, regulation, and role in neurogenic and non-neurogenic cutaneous inflammatory mechanisms. The mRNA of PACAP and its specific receptor PAC1 was detected with real-time PCR in several skin regions at comparable levels. PACAP-38-immunoreactivity measured with radioimmunoassay was similar in plantar and dorsal paw skin and the ear but significantly smaller in the back skin. PACAP and PAC1 mRNA, as well as PACAP-38 and PAC1 protein expression, significantly increased in the plantar skin after intraplantar administration of capsaicin (50 μl, 100 μg ml(-1)), an agonist of the transient receptor potential vanilloid 1 (TRPV1) receptor, evoking chiefly neurogenic inflammation without inflammatory cell accumulation. Intraplantar complete Freund's adjuvant (CFA; 50 μl, 1 mg ml(-1)) also increased PACAP/PAC1 mRNA but not the PACAP peptide. Capsaicin-induced neurogenic paw edema, but not CFA-evoked non-neurogenic swelling, was significantly smaller in PACAP-deficient mice throughout a 24-hour period. To our knowledge, we provide previously unreported evidence for PACAP and PAC1 expression upregulation during skin inflammation of different mechanisms and for its pro-inflammatory function in neurogenic edema formation.
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6
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He X, Meng F, Wang Y, Li J. Molecular cloning and characterization of two pig vasoactive intestinal polypeptide receptors (VPAC1-R and VPAC2-R). DNA Cell Biol 2014; 33:259-70. [PMID: 24520933 DOI: 10.1089/dna.2013.2235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We here report the cloning, tissue expression, and functional analyses of the two pig vasoactive intestinal polypeptide (VIP) receptors (pVPAC1-R and pVPAC2-R). The cloned full-length pVPAC1-R and pVPAC2-R share high structural similarity with their mammalian counterparts. Functional assay revealed that the full-length pVPAC1-R and pVPAC2-R-expressed Chinese hamster ovary (CHO) cells could be activated by pVIP and pPACAP38 potently, indicating that pVPAC1-R and pVPAC2-R are capable of binding VIP and pituitary adenylate cyclase-activating polypeptide (PACAP). In addition to the identification of the transcripts encoding the two full-length receptors, multiple splice transcript variants were isolated. Comparison with the pig genome database revealed that pVPAC1-R and pVPAC2-R share a unique gene structure with 14 exons different from other vertebrates. Reverse transcription and polymerase chain reaction (RT-PCR) assays further showed that the transcript encoding the full-length pVPAC2-R is widely expressed in all adult tissues whereas the splice variants of pVPAC1-R are predominantly expressed in all tissues instead of the transcript encoding the full-length receptor, hinting that pVPAC2-R may play more important roles than pVPAC1-R in mediating VIP and PACAP actions. Our present findings help to elucidate the important role of VIP and PACAP and promote to rethink of their species-specific physiological roles including their actions in regulation of phenotypic traits in pigs.
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Affiliation(s)
- Xiaping He
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University , Chengdu, People's Republic of China
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7
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Nemeth A, Szabadfi K, Fulop B, Reglodi D, Kiss P, Farkas J, Szalontai B, Gabriel R, Hashimoto H, Tamas A. Examination of calcium-binding protein expression in the inner ear of wild-type, heterozygous and homozygous pituitary adenylate cyclase-activating polypeptide (PACAP)-knockout mice in kanamycin-induced ototoxicity. Neurotox Res 2013; 25:57-67. [PMID: 24155155 DOI: 10.1007/s12640-013-9428-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 09/23/2013] [Accepted: 09/24/2013] [Indexed: 11/24/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with diverse biological effects. It also occurs and exerts protective effects in sensory organs; however, little is known about its effects in the auditory system. Recently, we have shown that PACAP protects cochlear cells against oxidative-stress-induced apoptosis and homozygous PACAP-deficient animals show stronger expression of Ca(2+)-binding proteins in the hair cells of the inner ear, but there are no data about the consequences of the lack of endogenous PACAP in different ototoxic insults such as aminoglycoside-induced toxicity. In this study, we examined the effect of kanamycin treatment on Ca(2+)-binding protein expression in hair cells of wild-type, heterozygous and homozygous PACAP-deficient mice. We treated 5-day-old mice with kanamycin, and 2 days later, we examined the Ca(2+)-binding protein expression of the hair cells with immunohistochemistry. We found stronger expression of Ca(2+)-binding proteins in the hair cells of control heterozygous and homozygous PACAP-deficient mice compared with wild-type animals. Kanamycin induced a significant increase in Ca(2+)-binding protein expression in wild-type and heterozygous PACAP-deficient mice, but the baseline higher expression in homozygous PACAP-deficient mice did not show further changes after the treatment. Elevated endolymphatic Ca(2+) is deleterious for the cochlear function, against which the high concentration of Ca(2+)-buffers in hair cells may protect. Meanwhile, the increased immunoreactivity of Ca(2+)-binding proteins in the absence of PACAP provide further evidence for the important protective role of PACAP in ototoxicity, but further investigations are necessary to examine the exact role of endogenous PACAP in ototoxic insults.
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Affiliation(s)
- A Nemeth
- Department of Oto-rhino-laryngology, University of Pecs, Pecs, Hungary
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8
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Blechman J, Levkowitz G. Alternative Splicing of the Pituitary Adenylate Cyclase-Activating Polypeptide Receptor PAC1: Mechanisms of Fine Tuning of Brain Activity. Front Endocrinol (Lausanne) 2013; 4:55. [PMID: 23734144 PMCID: PMC3659299 DOI: 10.3389/fendo.2013.00055] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Accepted: 04/24/2013] [Indexed: 12/11/2022] Open
Abstract
Alternative splicing of the precursor mRNA encoding for the neuropeptide receptor PAC1/ADCYAP1R1 generates multiple protein products that exhibit pleiotropic activities. Recent studies in mammals and zebrafish have implicated some of these splice isoforms in control of both cellular and body homeostasis. Here, we review the regulation of PAC1 splice variants and their underlying signal transduction and physiological processes in the nervous system.
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Affiliation(s)
- Janna Blechman
- Department of Molecular Cell Biology, Weizmann Institute of ScienceRehovot, Israel
| | - Gil Levkowitz
- Department of Molecular Cell Biology, Weizmann Institute of ScienceRehovot, Israel
- *Correspondence: Gil Levkowitz, Department of Molecular Cell Biology, Weizmann Institute of Science, P. O. Box 26, Rehovot 76100, Israel. e-mail:
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Tamas A, Szabadfi K, Nemeth A, Fulop B, Kiss P, Atlasz T, Gabriel R, Hashimoto H, Baba A, Shintani N, Helyes Z, Reglodi D. Comparative Examination of Inner Ear in Wild Type and Pituitary Adenylate Cyclase Activating Polypeptide (PACAP)-Deficient Mice. Neurotox Res 2011; 21:435-44. [DOI: 10.1007/s12640-011-9298-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Revised: 11/17/2011] [Accepted: 12/06/2011] [Indexed: 12/30/2022]
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10
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Racz B, Horvath G, Reglodi D, Gasz B, Kiss P, Gallyas F, Sumegi B, Toth G, Nemeth A, Lubics A, Tamas A. PACAP ameliorates oxidative stress in the chicken inner ear: an in vitro study. ACTA ACUST UNITED AC 2009; 160:91-8. [PMID: 19969027 DOI: 10.1016/j.regpep.2009.12.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 11/09/2009] [Accepted: 12/02/2009] [Indexed: 11/30/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a pleiotropic and multifunctional neuropeptide. Numerous studies prove that PACAP has neuroprotective effects in diverse neuronal systems in vitro and in vivo. The involvement of PACAP in visual and olfactory sensory processing has also been documented, but little is known about its effects in the auditory system. The presence of PACAP and its receptor, the specific PAC1 receptor, has been shown in the cochlea and in brain structures involved in auditory pathways. The aim of the present study was to investigate whether PACAP is protective in cochlear oxidative stress-induced cell death, which is known to play a role in several ototoxic insults. Chicken cochlear cells were exposed to 1mM H(2)O(2), which resulted in a marked reduction of cell viability and a parallel increase of apoptotic and necrotic cells assessed by MTT test, annexin V/propidium iodide flow cytometry and JC-1 apoptosis assay. Co-incubation with 100nM PACAP increased cell viability and reduced the percentage of apoptotic cells. Furthermore, oxidative stress increased the activation of caspase-3, while simultaneous PACAP treatment reduced it. In summary, our present results demonstrate that PACAP effectively protects cochlear cells against oxidative stress-induced apoptotic cell death.
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Affiliation(s)
- Boglarka Racz
- Department of Biochemistry and Medical Chemistry, University of Pecs, Hungary
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11
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Somogyi I, Boros A, Engelmann P, Varhalmi E, Nemeth J, Lubics A, Tamas A, Kiss P, Reglodi D, Pollak E, Molnar L. Pituitary adenylate cyclase-activating polypeptide-like compounds could modulate the activity of coelomocytes in the earthworm. Ann N Y Acad Sci 2009; 1163:521-3. [PMID: 19456404 DOI: 10.1111/j.1749-6632.2009.04431.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
By means of radioimmunoassay, we studied the concentration of pituitary adenylate cyclase-activating polypeptide (PACAP)-like proteins in intact and regenerating earthworms. Transection of animals increased the concentration of PACAP-like compounds in coelomocytes, and a decreasing rostrocaudal gradient was detected in the regenerating animals. Western blot analysis revealed a range of PAC1-receptor proteins with molecular weights from 40 to 80 kDa. Electron microscopic immunocytochemistry showed that PAC1 receptors were located on distinct sets of coelomocytes (mainly on amebocytes and on some granulocytes). Based on our results we hypothesize a link between PACAP and coelomocytes, suggesting that PACAP modulates the function of amebocytes and certain granulocytes that play a role in tissue remodeling of regenerating earthworms.
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Affiliation(s)
- Ildiko Somogyi
- Department of General Zoology, University of Pécs, Pécs, Hungary
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12
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13
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Gaal V, Mark L, Kiss P, Kustos I, Tamas A, Kocsis B, Lubics A, Nemeth V, Nemeth A, Lujber L, Pytel J, Toth G, Reglodi D. Investigation of the effects of PACAP on the composition of tear and endolymph proteins. J Mol Neurosci 2008; 36:321-9. [PMID: 18421426 DOI: 10.1007/s12031-008-9067-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Accepted: 03/12/2008] [Indexed: 12/30/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is widely distributed in ocular tissues, including the lacrimal gland. PACAP has been shown to influence the activity of several exocrine glands, but its effects on the composition of the tear film are not known yet. Similarly, the presence of PACAP has already been shown in the inner ear, but it is not known whether PACAP influences the composition of the endolymph. The aim of the present study was to investigate whether systemic injection of PACAP has any modulatory effects on the protein composition of the tear film and endolymph using chip electrophoresis and mass spectrometry analysis. Tear and endolymph samples were collected from rats and chickens, respectively, at various time points after systemic injection of PACAP. Fluid samples were further processed for chip electrophoretic studies. No difference was found in the protein composition of the endolymph between control and PACAP-treated animals. In contrast, tear samples showed a marked difference after PACAP treatment. Proteins in the molecular range 50-70 kDa, which showed a different chip electropherogram profile in every PACAP-treated sample, were further analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. PACAP treatment induced a repression in certain keratins, while others were induced after PACAP injection. Furthermore, PACAP treatment decreased aldehyde dehydrogenase expression. The present study provides a base for further studies on the in vivo effects of PACAP on the composition of tear film. These investigations may have important clinical relevance because of the noninvasive sample collection, the correlation between tear proteins and ocular diseases, and the possible presence of biomarkers for both ophthalmological and systemic pathological conditions.
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Affiliation(s)
- Valeria Gaal
- Department of Ophthalmology, University of Pecs, Ifjusag u 13, 7624, Pecs, Hungary
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14
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Khan KM, Drescher MJ, Hatfield JS, Ramakrishnan NA, Drescher DG. Immunohistochemical localization of adrenergic receptors in the rat organ of corti and spiral ganglion. J Neurosci Res 2008; 85:3000-12. [PMID: 17671986 DOI: 10.1002/jnr.21404] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Alpha(1)-, beta(1)-, and beta(2)-adrenergic receptors (ARs), which mediate responses to adrenergic input, have been immunohistochemically identified within the organ of Corti and spiral ganglion with polyclonal antibodies of established specificity. Alpha(1)-AR was immunolocalized to sites overlapping supranuclear regions of inner hair cells as well as to nerve fibers approaching the base of inner hair cells, most evident in the basal cochlear turn. A similar preponderance across cochlear turns for alpha(1)-AR in afferent cell bodies in the spiral ganglion pointed to type I afferent dendrites as a possible neural source of alpha(1)-AR beneath the inner hair cell. Foci of immunoreactivity for alpha(1)-AR, putatively neural, were found overlapping supranuclear and basal sites of outer hair cells for all turns. Beta(1)- and beta(2)-ARs were immunolocalized to sites overlapping apical and basal poles of the inner and outer hair cells, putatively neural in part, with immunoreactive nerve fibers observed passing through the habenula perforata. Beta(1)- and beta(2)-ARs were also detected in the cell bodies of Deiters' and Hensen's cells. Within the spiral ganglion, beta(1)- and beta(2)-ARs were immunolocalized to afferent cell bodies, with highest expression in the basal cochlear turn, constituting one possible neural source of receptors within the organ of Corti, specifically on type I afferent dendrites. Beta(1)- and beta(2)-ARs in Hensen's and Deiters' cells would couple to Galphas, known to be present specifically in the supporting cells. Overall, adrenergic modulation of neural/supporting cell function within the organ of Corti represents a newly considered mechanism for modifying afferent signaling.
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Affiliation(s)
- Khalid M Khan
- Laboratory of Bio-Otology, Department of Otolaryngology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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15
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Cardoso JCR, Vieira FA, Gomes AS, Power DM. PACAP, VIP and their receptors in the metazoa: insights about the origin and evolution of the ligand-receptor pair. Peptides 2007; 28:1902-19. [PMID: 17826180 DOI: 10.1016/j.peptides.2007.05.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 05/15/2007] [Accepted: 05/21/2007] [Indexed: 11/23/2022]
Abstract
The evolution, function and interaction of ligand-receptor pairs are of major pharmaceutical interest. Comparative sequence analysis approaches using data from phylogenetically distant organisms can provide insights into their origin and possible physiological roles. The present review focuses on the pituitary adenylate cyclase-activating polypeptide (PACAP), vasoactive intestinal polypeptide (VIP) and their receptors in the metazoa. A PACAP-like peptide is present in tunicates and chordates while VIP- and PACAP/VIP-specific receptors have only been isolated in the latter phyla. The apparently disparate evolution of the ligands and their specific receptors raises questions about their evolution during the metazoan radiation and also about how the ligands may have acquired new functions.
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Affiliation(s)
- João C R Cardoso
- Centre of Marine Sciences (CCMAR), Universidade do Algarve, Campus de Gambelas, Faro 8005-139, Portugal.
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16
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Helyes Z, Pozsgai G, Börzsei R, Németh J, Bagoly T, Márk L, Pintér E, Tóth G, Elekes K, Szolcsányi J, Reglodi D. Inhibitory effect of PACAP-38 on acute neurogenic and non-neurogenic inflammatory processes in the rat. Peptides 2007; 28:1847-55. [PMID: 17698245 DOI: 10.1016/j.peptides.2007.07.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 06/22/2007] [Accepted: 07/02/2007] [Indexed: 11/25/2022]
Abstract
Inhibitory actions of pituitary adenylate cyclase activating polypeptide (PACAP) have been described on cellular/vascular inflammatory components, but there are few data concerning its role in neurogenic inflammation. In this study we measured PACAP-like immunoreactivity with radioimmunoassay in the rat plasma and showed a two-fold elevation in response to systemic stimulation of capsaicin-sensitive sensory nerves by resiniferatoxin, but not after local excitation of cutaneous afferents. Neurogenic plasma extravasation in the plantar skin induced by intraplantar capsaicin or resiniferatoxin, as well as carrageenan-induced paw edema were significantly diminished by intraperitoneal PACAP-38. In summary, these results demonstrate that PACAP is released from activated capsaicin-sensitive afferents into the systemic circulation. It diminishes acute pure neurogenic and mixed-type inflammatory reactions via inhibiting pro-inflammatory mediator release and/or by acting at post-junctional targets on the vascular endothelium.
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Affiliation(s)
- Z Helyes
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Pécs, Hungary
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17
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Drescher MJ, Drescher DG, Khan KM, Hatfield JS, Ramakrishnan NA, Abu-Hamdan MD, Lemonnier LA. Pituitary adenylyl cyclase-activating polypeptide (PACAP) and its receptor (PAC1-R) are positioned to modulate afferent signaling in the cochlea. Neuroscience 2006; 142:139-64. [PMID: 16876955 DOI: 10.1016/j.neuroscience.2006.05.065] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Revised: 05/02/2006] [Accepted: 05/09/2006] [Indexed: 10/24/2022]
Abstract
Pituitary adenylyl cyclase-activating polypeptide (PACAP), via its specific receptor pituitary adenylyl cyclase-activating polypeptide receptor 1 (PAC1-R), is known to have roles in neuromodulation and neuroprotection associated with glutamatergic and cholinergic neurotransmission, which, respectively, are believed to form the primary basis for afferent and efferent signaling in the organ of Corti. Previously, we identified transcripts for PACAP preprotein and multiple splice variants of its receptor, PAC1-R, in microdissected cochlear subfractions. In the present work, neural localizations of PACAP and PAC1-R within the organ of Corti and spiral ganglion were examined, defining sites of PACAP action. Immunolocalization of PACAP and PAC1-R in the organ of Corti and spiral ganglion was compared with immunolocalization of choline acetyltransferase (ChAT) and synaptophysin as efferent neuronal markers, and glutamate receptor 2/3 (GluR2/3) and neurofilament 200 as afferent neuronal markers, for each of the three cochlear turns. Brightfield microscopy giving morphological detail for individual immunolocalizations was followed by immunofluorescence detection of co-localizations. PACAP was found to be co-localized with ChAT in nerve fibers of the intraganglionic spiral bundle and beneath the inner and outer hair cells within the organ of Corti. Further, evidence was obtained that PACAP is expressed in type I afferent axons leaving the spiral ganglion en route to the auditory nerve, potentially serving as a neuromodulator in axonal terminals. In contrast to the efferent localization of PACAP within the organ of Corti, PAC1-R immunoreactivity was co-localized with afferent dendritic neuronal marker GluR2/3 in nerve fibers passing beneath and lateral to the inner hair cell and in fibers at supranuclear and basal sites on outer hair cells. Given the known association of PACAP with catecholaminergic neurotransmission in sympathoadrenal function, we also re-examined the issue of whether the organ of Corti receives adrenergic innervation. We now demonstrate the existence of nerve fibers within the organ of Corti which are immunoreactive for the adrenergic marker dopamine beta-hydroxylase (DBH). DBH immunoreactivity was particularly prominent in nerve fibers both at the base and near the cuticular plate of outer hair cells of the apical turn, extending to the non-sensory Hensen's cell region. Evidence was obtained for limited co-localization of DBH with PAC1-R and PACAP. In the process of this investigation, we obtained evidence that efferent and afferent nerve fibers, in addition to adrenergic nerve fibers, are present at supranuclear sites on outer hair cells and distributed within the non-sensory epithelium of the apical cochlear turn for rat, based upon immunoreactivity for the corresponding neuronal markers. Overall, PACAP is hypothesized to act within the organ of Corti as an efferent neuromodulator of afferent signaling via PAC1-R that is present on type I afferent dendrites, in position to afford protection from excitotoxicity. Additionally, PACAP/PAC1-R may modulate secretion of catecholamines from adrenergic terminals within the organ of Corti.
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Affiliation(s)
- M J Drescher
- Laboratory of Bio-otology, Department of Otolaryngology, Wayne State University School of Medicine, 261 Lande Medical Research Building, 540 East Canfield Avenue, Detroit, MI 48201, USA.
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