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Lin PH, Kuo LT, Luh HT. The Roles of Neurotrophins in Traumatic Brain Injury. LIFE (BASEL, SWITZERLAND) 2021; 12:life12010026. [PMID: 35054419 PMCID: PMC8780368 DOI: 10.3390/life12010026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/18/2021] [Accepted: 12/21/2021] [Indexed: 02/08/2023]
Abstract
Neurotrophins are a collection of structurally and functionally related proteins. They play important roles in many aspects of neural development, survival, and plasticity. Traumatic brain injury (TBI) leads to different levels of central nervous tissue destruction and cellular repair through various compensatory mechanisms promoted by the injured brain. Many studies have shown that neurotrophins are key modulators of neuroinflammation, apoptosis, blood–brain barrier permeability, memory capacity, and neurite regeneration. The expression of neurotrophins following TBI is affected by the severity of injury, genetic polymorphism, and different post-traumatic time points. Emerging research is focused on the potential therapeutic applications of neurotrophins in managing TBI. We conducted a comprehensive review by organizing the studies that demonstrate the role of neurotrophins in the management of TBI.
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Affiliation(s)
- Ping-Hung Lin
- Department of Medical Education, School of Medicine, National Taiwan University, Taipei 100, Taiwan;
| | - Lu-Ting Kuo
- Division of Neurosurgery, Department of Surgery, National Taiwan University Hospital, Taipei 100, Taiwan;
| | - Hui-Tzung Luh
- Department of Neurosurgery, Shuang Ho Hospital, Taipei Medical University, New Taipei City 235, Taiwan
- Taipei Neuroscience Institute, Taipei Medical University, New Taipei City 235, Taiwan
- Graduate Institute of Clinical Medicine, National Taiwan University, Taipei 100, Taiwan
- Correspondence: ; Tel.: +886-956279587
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2
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Molecular Mechanism for PACAP 38-Induced Neurite Outgrowth in PC12 Cells. Neural Plast 2021; 2021:2522454. [PMID: 34422037 PMCID: PMC8371652 DOI: 10.1155/2021/2522454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/08/2021] [Accepted: 07/17/2021] [Indexed: 11/17/2022] Open
Abstract
The present research investigates the molecular mechanism of neurite outgrowth (protrusion elongation) under pituitary adenylate cyclase-activating polypeptide (PACAP) 38 treatments using a rat adrenal-derived pheochromocytoma cell line-PC12. This study specifically looks into the regulation of PACAP38-induced collapsing response mediator protein 2 (CRMP2) previously identified in a mouse brain ischemia model and which could be recovered by PACAP38 treatment. Previously, DNA microarray analysis revealed that PACAP 38-mediated neuroprotection involved not only CRMP2 but also pathways related to glycogen synthase kinase-3β (GSK-3β) and other signaling components. Thus, to clarify whether CRMP2 acts directly on PACAP38 or through GSK-3β as part of the mechanism of PACAP38-induced neurite outgrowth, we observed neurite outgrowth in the presence of GSK-3β inhibitors and activators. PC12 cells were treated with PACAP38 being added to the cell culture medium at concentrations of 10-7 M, 10-8 M, and 10-9 M. Post PACAP38 treatment, immunostaining was used to confirm protrusion elongation of the PC12 cells, while RT-PCR, two-dimensional gel electrophoresis in conjunction with Western blotting, and inhibition experiments were performed to confirm the expression of the PACAP gene, its receptors, and downstream signaling components. Our data show that neurite protrusion elongation by PACAP38 (10-7 M) in PC12 cells is mediated through the PAC1-R receptor as demonstrated by its suppression by a specific inhibitor PA-8. Inhibitor experiments suggested that PACAP38-triggered neurite protrusion follows a GSK-3β-regulated pathway, where the AKT and cAMP/ERK pathways are involved and where the inhibition of Rho/Roc could enhance neurite protrusion under PACAP38 stimulation. Although we could not yet confirm the exact role and position of CRMP2 in PACAP38-mediated PC12 cell elongation, it appears that its phosphorylation and dephosphorylation have a correlation with the neurite protrusion elongation through the interplay of CDK5, which needs to be investigated further.
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Kvarik T, Reglodi D, Werling D, Vaczy A, Kovari P, Szabo E, Kovacs K, Hashimoto H, Ertl T, Gyarmati J, Atlasz T. The Protective Effects of Endogenous PACAP in Oxygen-Induced Retinopathy. J Mol Neurosci 2021; 71:2546-2557. [PMID: 33895966 PMCID: PMC8602170 DOI: 10.1007/s12031-021-01846-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 04/13/2021] [Indexed: 12/17/2022]
Abstract
Pituitary adenylate cyclase–activating polypeptide (PACAP) is a neuropeptide having trophic and protective functions in neural tissues, including the retina. Previously, we have shown that intravitreal PACAP administration can maintain retinal structure in the animal model of retinopathy of prematurity (ROP). The purpose of this study is to examine the development of ROP in PACAP-deficient and wild-type mice to reveal the function of endogenous PACAP. Wild-type and PACAP-knockout (KO) mouse pups at postnatal day (PD) 7 were maintained at 75% oxygen for 5 consecutive days then returned to room air on PD12 to develop oxygen-induced retinopathy (OIR). On PD15, animals underwent electroretinography (ERG) to assess visual function. On PD16, eyes were harvested for either immunohistochemistry to determine the percentage of the central avascular retinal area or molecular analysis to assess angiogenesis proteins by array kit and anti-apoptotic protein kinase B (Akt) change by western blot. Retinas of PACAP-deficient OIR mice showed a greater central avascular area than that of the wild types. ERG revealed significantly decreased b-wave amplitude in PACAP KO compared to their controls. Several angiogenic proteins were upregulated due to OIR, and 11 different proteins markedly increased in PACAP-deficient mice, whereas western blot analysis revealed a reduction in Akt phosphorylation, suggesting an advanced cell death in the lack of PACAP. This is the first study to examine the endogenous effect of PACAP in the OIR model. Previously, we have shown the beneficial effect of exogenous local PACAP treatment in the rat OIR model. Together with the present findings, we suggest that PACAP could be a novel retinoprotective agent in ROP.
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Affiliation(s)
- Timea Kvarik
- Department of Anatomy, MTA-PTE PACAP Research Team, Medical School, University of Pecs, Pecs, Hungary.,Department of Obstetrics and Gynecology, Medical School, University of Pecs, Pecs, Hungary
| | - Dora Reglodi
- Department of Anatomy, MTA-PTE PACAP Research Team, Medical School, University of Pecs, Pecs, Hungary
| | - Dora Werling
- Department of Anatomy, MTA-PTE PACAP Research Team, Medical School, University of Pecs, Pecs, Hungary
| | - Alexandra Vaczy
- Department of Anatomy, MTA-PTE PACAP Research Team, Medical School, University of Pecs, Pecs, Hungary
| | - Petra Kovari
- Department of Anatomy, MTA-PTE PACAP Research Team, Medical School, University of Pecs, Pecs, Hungary
| | - Edina Szabo
- Department of Anatomy, MTA-PTE PACAP Research Team, Medical School, University of Pecs, Pecs, Hungary
| | - Krisztina Kovacs
- Department of Biochemistry and Medical Chemistry, Medical School, University of Pecs, Pecs, Hungary
| | - Hitoshi Hashimoto
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Tibor Ertl
- Department of Obstetrics and Gynecology, Medical School, University of Pecs, Pecs, Hungary
| | - Judit Gyarmati
- Department of Obstetrics and Gynecology, Medical School, University of Pecs, Pecs, Hungary
| | - Tamas Atlasz
- Department of Anatomy, MTA-PTE PACAP Research Team, Medical School, University of Pecs, Pecs, Hungary. .,Department of Sportbiology, University of Pecs, Pecs, Hungary.
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4
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Fang Y, Ren R, Shi H, Huang L, Lenahan C, Lu Q, Tang L, Huang Y, Tang J, Zhang J, Zhang JH. Pituitary Adenylate Cyclase-Activating Polypeptide: A Promising Neuroprotective Peptide in Stroke. Aging Dis 2020; 11:1496-1512. [PMID: 33269103 PMCID: PMC7673855 DOI: 10.14336/ad.2020.0626] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 06/26/2020] [Indexed: 12/11/2022] Open
Abstract
The search for viable, effective treatments for acute stroke continues to be a global priority due to the high mortality and morbidity. Current therapeutic treatments have limited effects, making the search for new treatments imperative. Pituitary adenylate cyclase-activating polypeptide (PACAP) is a well-established cytoprotective neuropeptide that participates in diverse neural physiological and pathological activities, such as neuronal proliferation, differentiation, and migration, as well as neuroprotection. It is considered a promising treatment in numerous neurological diseases. Thus, PACAP bears potential as a new therapeutic strategy for stroke treatment. Herein, we provide an overview pertaining to the current knowledge of PACAP, its receptors, and its potential neuroprotective role in the setting of stroke, as well as various mechanisms of neuroprotection involving ionic homeostasis, excitotoxicity, cell edema, oxidative stress, inflammation, and cell death, as well as the route of PACAP administration.
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Affiliation(s)
- Yuanjian Fang
- 1Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Reng Ren
- 1Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hui Shi
- 2Department of Neurosurgery, Yongchuan Hospital, Chongqing Medical University, Chongqing, China
| | - Lei Huang
- 3Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,4Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA
| | - Cameron Lenahan
- 3Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,4Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA.,5Burrell College of Osteopathic Medicine, Las Cruces, NM, USA
| | - Qin Lu
- 6Department of Neurosurgery, Sir Run Run Shaw Hospital, Zhejiang University, School of Medicine, Hangzhou, Zhejiang, China
| | - Lihui Tang
- 1Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yi Huang
- 1Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jiping Tang
- 3Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,4Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA.,7Department of Anesthesiology, Loma Linda University, Loma Linda, CA, USA
| | - Jianmin Zhang
- 1Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - John H Zhang
- 3Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,4Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA.,7Department of Anesthesiology, Loma Linda University, Loma Linda, CA, USA
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5
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Fang Y, Shi H, Ren R, Huang L, Okada T, Lenahan C, Gamdzyk M, Travis ZD, Lu Q, Tang L, Huang Y, Zhou K, Tang J, Zhang J, Zhang JH. Pituitary Adenylate Cyclase-Activating Polypeptide Attenuates Brain Edema by Protecting Blood-Brain Barrier and Glymphatic System After Subarachnoid Hemorrhage in Rats. Neurotherapeutics 2020; 17:1954-1972. [PMID: 32918234 PMCID: PMC7851266 DOI: 10.1007/s13311-020-00925-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2020] [Indexed: 12/14/2022] Open
Abstract
Brain edema is a vital contributor to early brain injury after subarachnoid hemorrhage (SAH), which is responsible for prolonged hospitalization and poor outcomes. Pharmacological therapeutic targets on edema formation have been the focus of research for decades. Pituitary adenylate cyclase-activating polypeptide (PACAP) has been shown to participate in neural development and brain injury. Here, we used PACAP knockout CRISPR to demonstrate that endogenous PACAP plays an endogenous neuroprotective role against brain edema formation after SAH in rats. The exogenous PACAP treatment provided both short- and long-term neurological benefits by preserving the function of the blood-brain barrier and glymphatic system after SAH. Pretreatment of inhibitors of PACAP receptors showed that the PACAP-involved anti-edema effect and neuroprotection after SAH was facilitated by the selective PACAP receptor (PAC1). Further administration of adenylyl cyclase (AC) inhibitor and sulfonylurea receptor 1 (SUR1) CRISPR activator suggested that the AC-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) axis participated in PACAP signaling after SAH, which inhibited the expression of edema-related proteins, SUR1 and aquaporin-4 (AQP4), through SUR1 phosphorylation. Thus, PACAP may serve as a potential clinical treatment to alleviate brain edema in patients with SAH.
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Affiliation(s)
- Yuanjian Fang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Zhejiang, 310009, Hangzhou, China
| | - Hui Shi
- Department of Neurosurgery, Yongchuan Hospital, Chongqing Medical University, Chongqing, China
| | - Reng Ren
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Zhejiang, 310009, Hangzhou, China
| | - Lei Huang
- Department of Neurosurgery, Loma Linda University, Loma Linda, California, USA
- Department of Physiology and Pharmacology, Loma Linda University, 11041 Campus St, Risley Hall, Room 219, Loma Linda, California, 92354, USA
| | - Takeshi Okada
- Department of Neurosurgery, Loma Linda University, Loma Linda, California, USA
- Department of Physiology and Pharmacology, Loma Linda University, 11041 Campus St, Risley Hall, Room 219, Loma Linda, California, 92354, USA
| | - Cameron Lenahan
- Department of Neurosurgery, Loma Linda University, Loma Linda, California, USA
- Burrell College of Osteopathic Medicine, Las Cruces, New Mexico, USA
| | - Marcin Gamdzyk
- Department of Neurosurgery, Loma Linda University, Loma Linda, California, USA
| | - Zachary D Travis
- Department of Neurosurgery, Loma Linda University, Loma Linda, California, USA
| | - Qin Lu
- Department of Neurosurgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Lihui Tang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Zhejiang, 310009, Hangzhou, China
| | - Yi Huang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Zhejiang, 310009, Hangzhou, China
| | - Keren Zhou
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Zhejiang, 310009, Hangzhou, China
| | - Jiping Tang
- Department of Neurosurgery, Loma Linda University, Loma Linda, California, USA
- Department of Physiology and Pharmacology, Loma Linda University, 11041 Campus St, Risley Hall, Room 219, Loma Linda, California, 92354, USA
- Department of Anesthesiology, Loma Linda University, Loma Linda, California, USA
| | - Jianmin Zhang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Zhejiang, 310009, Hangzhou, China.
| | - John H Zhang
- Department of Neurosurgery, Loma Linda University, Loma Linda, California, USA.
- Department of Physiology and Pharmacology, Loma Linda University, 11041 Campus St, Risley Hall, Room 219, Loma Linda, California, 92354, USA.
- Department of Anesthesiology, Loma Linda University, Loma Linda, California, USA.
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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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7
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IL-6 knockout mice are protected from cocaine-induced kindling behaviors; possible involvement of JAK2/STAT3 and PACAP signalings. Food Chem Toxicol 2018; 116:249-263. [PMID: 29673861 DOI: 10.1016/j.fct.2018.04.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 03/27/2018] [Accepted: 04/13/2018] [Indexed: 01/12/2023]
Abstract
IL-6 has been recognized as an anticonvulsant against certain neuroexcitotoxicities. We aimed to investigate on the interactive role between IL-6 and PACAP in cocaine-induced kindling behaviors. Although we found that cocaine (45 mg/kg, i.p./day x 5) significantly increased IL-6 and TNF-α expression, it resulted in a decrease in IFN-γ expression. We observed that the cocaine-induced increase in IL-6 expression was more pronounced than that in TNF-α expression. Genetic depletion of IL-6 significantly activated cocaine kindling behaviors. This phenomenon was also consistently observed in WT mice that received a neutralizing IL-6 receptor antibody. Cocaine-treated IL-6 knockout mice exhibited significantly decreased PACAP and PACAP receptor (PAC1R) mRNA levels and significantly increased TNF-α gene expression. TNF-α knockout mice were protected from cocaine kindling via an up-regulation of IL-6, phospho-JAK2/STAT3, PACAP, and PAC1R levels, which produced anti-apoptotic effects. Recombinant IL-6 protein (rIL-6, 2 μg, i.v./mouse/day x 5) also up-regulated phospho-JAK2/STAT3, PACAP, and PAC1R mRNA levels, leading to anti-apoptotic effects in IL-6 knockout mice. Consistently, AG490, a JAK2/STAT3 inhibitor, and PACAP 6-38, a PAC1 receptor antagonist, counteracted rIL-6-mediated protection. Combined, our results suggest that IL-6 gene requires up-regulation of phospho-JAK2/STAT3, PACAP, and PAC1R and down-regulation of the TNF-α gene to modulate its anticonvulsive/neuroprotective potential.
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Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is an ubiquitous peptide involved, among others, in neurodevelopment, neuromodulation, neuroprotection, neurogenic inflammation and nociception. Presence of PACAP and its specific receptor, PAC1, in the trigeminocervical complex, changes of PACAP levels in migraine patients and the migraine-inducing effect of PACAP injection strongly support the involvement of PACAP/PAC1 receptor in migraine pathogenesis. While antagonizing PAC1 receptor is a promising therapeutic target in migraine, the diverse array of PACAP's functions, including protection in ischemic events, requires that the cost-benefit of such an intervention is well investigated by taking all the beneficial effects of PACAP into account. In the present review we summarize the protective effects of PACAP in ischemia, especially in neuronal ischemic injuries, and discuss possible points to consider when developing strategies in migraine therapy interfering with the PACAP/PAC1 receptor system.
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Farkas J, Sandor B, Tamas A, Kiss P, Hashimoto H, Nagy AD, Fulop BD, Juhasz T, Manavalan S, Reglodi D. Early Neurobehavioral Development of Mice Lacking Endogenous PACAP. J Mol Neurosci 2017; 61:468-478. [PMID: 28168413 DOI: 10.1007/s12031-017-0887-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 01/13/2017] [Indexed: 02/06/2023]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a multifunctional neuropeptide. In addition to its diverse physiological roles, PACAP has important functions in the embryonic development of various tissues, and it is also considered as a trophic factor during development and in the case of neuronal injuries. Data suggest that the development of the nervous system is severely affected by the lack of endogenous PACAP. Short-term neurofunctional outcome correlates with long-term functional deficits; however, the early neurobehavioral development of PACAP-deficient mice has not yet been evaluated. Therefore, the aim of the present study was to describe the postnatal development of physical signs and neurological reflexes in mice partially or completely lacking PACAP. We examined developmental hallmarks during the first 3 weeks of the postnatal period, during which period most neurological reflexes and motor coordination show most intensive development, and we describe the neurobehavioral development using a complex battery of tests. In the present study, we found that PACAP-deficient mice had slower weight gain throughout the observation period. Interestingly, mice partially lacking PACAP weighed significantly less than homozygous mice. There was no difference between male and female mice during the first 3 weeks. Some other signs were also more severely affected in the heterozygous mice than in the homozygous mice, such as air righting, grasp, and gait initiation reflexes. Interestingly, incisor teeth erupted earlier in mice lacking PACAP. Motor coordination, shown by the number of foot-faults on an elevated grid, was also less developed in PACAP-deficient mice. In summary, our results show that mice lacking endogenous PACAP have slower weight gain during the first weeks of development and slower neurobehavioral development regarding a few developmental hallmarks.
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Affiliation(s)
- Jozsef Farkas
- Department of Anatomy, Medical School, University of Pecs, Szigeti u 12, 7624, Pecs, Hungary
| | - Balazs Sandor
- Department of Anatomy, Medical School, University of Pecs, Szigeti u 12, 7624, Pecs, Hungary.,Department of Dentistry, Oral and Maxillofacial Surgery, University of Pecs, Pecs, Hungary
| | - Andrea Tamas
- Department of Anatomy, Medical School, University of Pecs, Szigeti u 12, 7624, Pecs, Hungary
| | - Peter Kiss
- Department of Anatomy, Medical School, University of Pecs, Szigeti u 12, 7624, Pecs, Hungary
| | - Hitoshi Hashimoto
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences and Molecular Research Center for Children's Mental Development, United Graduate School of Child Development, Osaka University, Osaka, Japan
| | - Andras D Nagy
- Department of Anatomy, Medical School, University of Pecs, Szigeti u 12, 7624, Pecs, Hungary
| | - Balazs D Fulop
- Department of Anatomy, Medical School, University of Pecs, Szigeti u 12, 7624, Pecs, Hungary
| | - Tamas Juhasz
- Department of Anatomy, Histology and Embryology, University of Debrecen, Debrecen, Hungary
| | - Sridharan Manavalan
- Department of Anatomy, Medical School, University of Pecs, Szigeti u 12, 7624, Pecs, Hungary.,Department of Basic Sciences, National University of Health Sciences, Florida, USA
| | - Dora Reglodi
- Department of Anatomy, Medical School, University of Pecs, Szigeti u 12, 7624, Pecs, Hungary.
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10
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Shioda S, Nakamachi T. PACAP as a neuroprotective factor in ischemic neuronal injuries. Peptides 2015; 72:202-7. [PMID: 26275482 DOI: 10.1016/j.peptides.2015.08.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 08/06/2015] [Accepted: 08/06/2015] [Indexed: 10/23/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a 27- or 38-amino acid neuropeptide, which belongs to the vasoactive intestinal polypeptide/glucagon/secretin family. PACAP and its three receptor subtypes are expressed in neural tissues, with PACAP known to exert pleiotropic effects on the nervous system. This review provides an overview of current knowledge regarding the neuroprotective effects, mechanisms of action, and therapeutic potential of PACAP in response to ischemic brain injuries.
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Affiliation(s)
- Seiji Shioda
- Global Research Center for Innovative Life Science, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
| | - Tomoya Nakamachi
- Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan
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11
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Hori M, Nakamachi T, Shibato J, Rakwal R, Shioda S, Numazawa S. Unraveling the Specific Ischemic Core and Penumbra Transcriptome in the Permanent Middle Cerebral Artery Occlusion Mouse Model Brain Treated with the Neuropeptide PACAP38. MICROARRAYS 2015; 4:2-24. [PMID: 27600210 PMCID: PMC4996388 DOI: 10.3390/microarrays4010002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/15/2015] [Indexed: 01/01/2023]
Abstract
Our group has been systematically investigating the effects of the neuropeptide pituitary adenylate-cyclase activating polypeptide (PACAP) on the ischemic brain. To do so, we have established and utilized the permanent middle cerebral artery occlusion (PMCAO) mouse model, in which PACAP38 (1 pmol) injection is given intracerebroventrically and compared to a control saline (0.9% sodium chloride, NaCl) injection, to unravel genome‑wide gene expression changes using a high-throughput DNA microarray analysis approach. In our previous studies, we have accumulated a large volume of data (gene inventory) from the whole brain (ipsilateral and contralateral hemispheres) after both PMCAO and post-PACAP38 injection. In our latest research, we have targeted specifically infarct or ischemic core (hereafter abbreviated IC) and penumbra (hereafter abbreviated P) post-PACAP38 injections in order to re-examine the transcriptome at 6 and 24 h post injection. The current study aims to delineate the specificity of expression and localization of differentially expressed molecular factors influenced by PACAP38 in the IC and P regions. Utilizing the mouse 4 × 44 K whole genome DNA chip we show numerous changes (≧/≦ 1.5/0.75-fold) at both 6 h (654 and 456, and 522 and 449 up- and down-regulated genes for IC and P, respectively) and 24 h (2568 and 2684, and 1947 and 1592 up- and down-regulated genes for IC and P, respectively) after PACAP38 treatment. Among the gene inventories obtained here, two genes, brain-derived neurotrophic factor (Bdnf) and transthyretin (Ttr) were found to be induced by PACAP38 treatment, which we had not been able to identify previously using the whole hemisphere transcriptome analysis. Using bioinformatics analysis by pathway- or specific-disease-state focused gene classifications and Ingenuity Pathway Analysis (IPA) the differentially expressed genes are functionally classified and discussed. Among these, we specifically discuss some novel and previously identified genes, such as alpha hemoglobin stabilizing protein (Ahsp), cathelicidin antimicrobial peptide (Camp), chemokines, interferon beta 1 (Ifnb1), and interleukin 6 (Il6) in context of PACAP38-mediated neuroprotection in the ischemic brain. Taken together, the DNA microarray analysis provides not only a great resource for further study, but also reinforces the importance of region-specific analyses in genome-wide identification of target molecular factors that might play a role in the neuroprotective function of PACAP38.
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Affiliation(s)
- Motohide Hori
- Division of Toxicology, Department of Pharmacology, Toxicology and Therapeutics, School of Pharmacy, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555, Japan.
- Department of Anatomy, School of Medicine, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555, Japan.
| | - Tomoya Nakamachi
- Department of Anatomy, School of Medicine, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555, Japan.
- Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, Toyama, Toyama 930-8555, Japan.
| | - Junko Shibato
- Department of Anatomy, School of Medicine, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555, Japan.
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Institute of Health and Sports Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8574, Japan.
| | - Randeep Rakwal
- Department of Anatomy, School of Medicine, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555, Japan.
- Organization for Educational Initiatives, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8577, Japan.
| | - Seiji Shioda
- Department of Anatomy, School of Medicine, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555, Japan.
| | - Satoshi Numazawa
- Division of Toxicology, Department of Pharmacology, Toxicology and Therapeutics, School of Pharmacy, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555, Japan.
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Jóźwiak-Bębenista M, Kowalczyk E, Nowak JZ. The cyclic AMP effects and neuroprotective activities of PACAP and VIP in cultured astrocytes and neurons exposed to oxygen-glucose deprivation. Pharmacol Rep 2014; 67:332-8. [PMID: 25712659 DOI: 10.1016/j.pharep.2014.10.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 09/24/2014] [Accepted: 10/02/2014] [Indexed: 01/30/2023]
Abstract
BACKGROUND Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) are endogenous peptides, widely expressed in the central and peripheral nervous system. The adenylyl cyclase (AC)/cyclic AMP (cAMP) is their main intracellular signal transduction pathway. Numerous data suggest that PACAP and VIP have considerable neuroprotective potential, indicating the possibility for their use as new therapeutic strategies in stroke treatment. The aim of this study was to evaluate the effect of oxygen-glucose deprivation (OGD) - an established in vitro model for ischemic cell stress - on PACAP and VIP-evoked receptor-mediated cAMP generation in glial and neuronal cells, and to determine whether PACAP and VIP have neuroprotective activity under these conditions. METHODS The formation of [(3)H]cAMP by PACAP, VIP and forskolin (a direct activator of AC) was measured in [(3)H]adenine prelabeled primary rat glial and neuronal cells under normoxia and OGD conditions. The effects of PACAP and VIP on cell viability were measured using the MTT conversion method, and were compared to tacrolimus (FK506), a well known neuroprotective agent. RESULTS The OGD model inhibited the PACAP and VIP-induced cAMP formation in rat astrocytes and neurons. Incubation of neuronal cells with PACAP prevented OGD-induced cell death, more efficiently than VIP and FK506. CONCLUSION The obtained results showed that hypoxia/ischemia may trigger down-regulation of the brain AC-coupled PACAP/VIP receptors, with a consequent decrease of PACAP- and/or VIP-ergic-dependent cAMP-driven signaling. Moreover, our findings indicate that PACAP and VIP can prevent the deleterious effect of OGD on rat neuronal cells.
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Affiliation(s)
- Marta Jóźwiak-Bębenista
- Department of Pharmacology and Toxicology, The Interfaculty Chair of Basic and Clinical Pharmacology, Medical University of Lodz, Łódź, Poland.
| | - Edward Kowalczyk
- Department of Pharmacology and Toxicology, The Interfaculty Chair of Basic and Clinical Pharmacology, Medical University of Lodz, Łódź, Poland
| | - Jerzy Z Nowak
- Department of Pharmacology and Toxicology, The Interfaculty Chair of Basic and Clinical Pharmacology, Medical University of Lodz, Łódź, Poland
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PACAP38 differentially effects genes and CRMP2 protein expression in ischemic core and penumbra regions of permanent middle cerebral artery occlusion model mice brain. Int J Mol Sci 2014; 15:17014-34. [PMID: 25257527 PMCID: PMC4200817 DOI: 10.3390/ijms150917014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 09/05/2014] [Accepted: 09/10/2014] [Indexed: 11/17/2022] Open
Abstract
Pituitary adenylate-cyclase activating polypeptide (PACAP) has neuroprotective and axonal guidance functions, but the mechanisms behind such actions remain unclear. Previously we examined effects of PACAP (PACAP38, 1 pmol) injection intracerebroventrically in a mouse model of permanent middle cerebral artery occlusion (PMCAO) along with control saline (0.9% NaCl) injection. Transcriptomic and proteomic approaches using ischemic (ipsilateral) brain hemisphere revealed differentially regulated genes and proteins by PACAP38 at 6 and 24 h post-treatment. However, as the ischemic hemisphere consisted of infarct core, penumbra, and non-ischemic regions, specificity of expression and localization of these identified molecular factors remained incomplete. This led us to devise a new experimental strategy wherein, ischemic core and penumbra were carefully sampled and compared to the corresponding contralateral (healthy) core and penumbra regions at 6 and 24 h post PACAP38 or saline injections. Both reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were used to examine targeted gene expressions and the collapsin response mediator protein 2 (CRMP2) protein profiles, respectively. Clear differences in expression of genes and CRMP2 protein abundance and degradation product/short isoform was observed between ischemic core and penumbra and also compared to the contralateral healthy tissues after PACAP38 or saline treatment. Results indicate the importance of region-specific analyses to further identify, localize and functionally analyse target molecular factors for clarifying the neuroprotective function of PACAP38.
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Tsuchida M, Nakamachi T, Sugiyama K, Tsuchikawa D, Watanabe J, Hori M, Yoshikawa A, Imai N, Kagami N, Matkovits A, Atsumi T, Shioda S. PACAP Stimulates Functional Recovery after Spinal Cord Injury through Axonal Regeneration. J Mol Neurosci 2014; 54:380-7. [DOI: 10.1007/s12031-014-0338-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 05/20/2014] [Indexed: 12/19/2022]
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15
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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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16
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Mao SS, Hua R, Zhao XP, Qin X, Sun ZQ, Zhang Y, Wu YQ, Jia MX, Cao JL, Zhang YM. Exogenous administration of PACAP alleviates traumatic brain injury in rats through a mechanism involving the TLR4/MyD88/NF-κB pathway. J Neurotrauma 2013; 29:1941-59. [PMID: 22583372 DOI: 10.1089/neu.2011.2244] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is effective in reducing axonal damage associated with traumatic brain injury (TBI), and has immunomodulatory properties. Toll-like receptor 4 (TLR4) is an important mediator of the innate immune response. It significantly contributes to neuroinflammation induced by brain injury. However, it remains unknown whether exogenous PACAP can modulate TBI through the TLR4/adapter protein myeloid differentiation factor 88 (MyD88)/nuclear factor-κB (NF-κB) signaling pathway. In this study, we investigated the potential neuroprotective mechanisms of PACAP pretreatment in a weight-drop model of TBI. PACAP38 was microinjected intracerebroventricularly before TBI. Brain samples were extracted from the pericontusional area in the cortex and hippocampus. We found that TBI induced significant upregulation of TLR4, with peak expression occurring 24 h post-trauma, and that pretreatment with PACAP significantly improved motor and cognitive dysfunction, attenuated neuronal apoptosis, and decreased brain edema. Pretreatment with PACAP inhibited upregulation of TLR4 and its downstream signaling molecules MyD88, p-IκB, and NF-κB, and suppressed increases in the levels of the downstream inflammatory agents interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), in the brain tissue around the injured cortex and in the hippocampus. Administration of PACAP both in vitro and in vivo attenuated the ability of the TLR4 agonist lipopolysaccharide (LPS) to increase TLR4 protein levels. Therefore, PACAP exerts a neuroprotective effect in this rat model of TBI, by inhibiting a secondary inflammatory response mediated by the TLR4/MyD88/NF-κB signaling pathway in microglia and neurons, thereby reducing neuronal death and improving the outcome following TBI.
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Affiliation(s)
- Shan-Shan Mao
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical College, Xuzhou, Jiangsu, China
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Nakamachi T, Farkas J, Kagami N, Wada Y, Hori M, Tsuchikawa D, Tsuchida M, Yoshikawa A, Imai N, Hosono T, Atrata S, Shioda S. Expression and distribution of pituitary adenylate cyclase-activating polypeptide receptor in reactive astrocytes induced by global brain ischemia in mice. ACTA NEUROCHIRURGICA. SUPPLEMENT 2013; 118:55-9. [PMID: 23564104 DOI: 10.1007/978-3-7091-1434-6_9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide acting as a neuroprotectant. We previously showed that PACAP receptor (PAC1R) immunoreactivity was elevated in reactive astrocytes after stab wound injury. However, the pattern of PAC1R expression in astrocytes after brain injury is still unknown. In this study, PAC1R expression was evaluated in mouse hippocampal astrocytes after bilateral common carotid artery occlusion. PAC1R mRNA levels in the hippocampus peaked on day 7, and glial fibrillary acidic protein (GFAP) mRNA levels increased from day 3 to day 7 after ischemia. We then observed co-localization of PAC1R and GFAP by double immunostaining. GFAP-immunopositive cells showed signs of hypertrophy 3 days after the ischemia, and by day 7 had fine processes, were hypertrophied, and are known as reactive astrocytes. A low number of PAC1R-immunopositive astrocytes were detectable in the hippocampal area until 3 days after ischemia. PAC1R-positive astrocytes were widely distributed in the hippocampus between day 7 and day 14 after ischemia, and they were converging around the damaged CA1 pyramidal cell layer by day 28. These results suggest that PAC1R might be expressed in the middle to late stage of reactive astrocytes and PACAP plays an important role in the reactive astrocytes after brain injury.
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Affiliation(s)
- Tomoya Nakamachi
- Department of Anatomy, Showa University School of Medicine, Tokyo, Japan
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Lazarovici P, Cohen G, Arien-Zakay H, Chen J, Zhang C, Chopp M, Jiang H. Multimodal neuroprotection induced by PACAP38 in oxygen-glucose deprivation and middle cerebral artery occlusion stroke models. J Mol Neurosci 2012; 48:526-40. [PMID: 22678884 DOI: 10.1007/s12031-012-9818-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2012] [Accepted: 05/21/2012] [Indexed: 01/30/2023]
Abstract
Pituitary adenylate cyclase activating peptide (PACAP), a potent neuropeptide which crosses the blood-brain barrier, is known to provide neuroprotection in rat stroke models of middle cerebral artery occlusion (MCAO) by mechanism(s) which deserve clarification. We confirmed that following i.v. injection of 30 ng/kg of PACAP38 in rats exposed to 2 h of MCAO focal cerebral ischemia and 48 h reoxygenation, 50 % neuroprotection was measured by reduced caspase-3 activity and volume of cerebral infarction. Similar neuroprotective effects were measured upon PACAP38 treatment of oxygen-glucose deprivation and reoxygenation of brain cortical neurons. The neuroprotection was temporally associated with increased expression of brain-derived neurotrophic factor, phosphorylation of its receptor-tropomyosin-related kinase receptor type B (trkB), activation of phosphoinositide 3-kinase and Akt, and reduction of extracellular signal-regulated kinases 1/2 phosphorylation. PACAP38 increased expression of neuronal markers beta-tubulin III, microtubule-associated protein-2, and growth-associated protein-43. PACAP38 induced stimulation of Rac and suppression of Rho GTPase activities. PACAP38 downregulated the nerve growth factor receptor (p75(NTR)) and associated Nogo-(Neurite outgrowth-A) receptor. Collectively, these in vitro and in vivo results propose that PACAP exhibits neuroprotective effects in cerebral ischemia by three mechanisms: a direct one, mediated by PACAP receptors, and two indirect, induced by neurotrophin release, activation of the trkB receptors and attenuation of neuronal growth inhibitory signaling molecules p75(NTR) and Nogo receptor.
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Affiliation(s)
- Philip Lazarovici
- School of Pharmacy Institute for Drug Research, The Hebrew University of Jerusalem, POB 12065, Jerusalem 91120, Israel.
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Neuroprotective effect of endogenous pituitary adenylate cyclase-activating polypeptide on spinal cord injury. J Mol Neurosci 2012; 48:508-17. [PMID: 22674051 DOI: 10.1007/s12031-012-9817-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Accepted: 05/17/2012] [Indexed: 02/06/2023]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuroprotective peptide expressed in the central nervous system. To date, changes in the expression and effect of endogenous PACAP have not been clarified with respect to spinal cord injury (SCI). The aim of this study was to elucidate the expression pattern and function of endogenous PACAP on the contusion model of SCI using heterozygous PACAP knockout (PACAP(+/-)) and wild-type mice. Real-time polymerase chain reaction methods revealed that the level of PACAP mRNA increased gradually for 14 days after SCI and that PAC1R mRNA levels also increased for 7 days compared with intact control mice. PACAP and PAC1R immunoreactivities colabeled with a neuronal marker in the intact spinal cord. Seven days after SCI, PAC1R immunoreactivity was additionally co-expressed with an astrocyte marker. Wild-type mice gradually recovered motor function after 14 days, but PACAP(+/-) mice showed significantly impaired recovery from 3 days compared with wild-type mice. The injury volume at day 7 in PACAP(+/-) mice, and the number of single-stranded DNA-immunopositive cells as a marker of neuronal cell death at day 3 were significantly higher than values measured in wild-type mice. These data suggest that endogenous PACAP is upregulated by SCI and has a neuroprotective effect on the damaged spinal cord.
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IL-6 and PACAP Receptor Expression and Localization after Global Brain Ischemia in Mice. J Mol Neurosci 2012; 48:518-25. [DOI: 10.1007/s12031-012-9819-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 05/21/2012] [Indexed: 10/28/2022]
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21
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PACAP is an Endogenous Protective Factor—Insights from PACAP-Deficient Mice. J Mol Neurosci 2012; 48:482-92. [DOI: 10.1007/s12031-012-9762-0] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 03/22/2012] [Indexed: 01/07/2023]
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22
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Reglodi D, Kiss P, Horvath G, Lubics A, Laszlo E, Tamas A, Racz B, Szakaly P. Effects of pituitary adenylate cyclase activating polypeptide in the urinary system, with special emphasis on its protective effects in the kidney. Neuropeptides 2012; 46:61-70. [PMID: 21621841 DOI: 10.1016/j.npep.2011.05.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 05/03/2011] [Indexed: 10/18/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a widespread neuropeptide with diverse effects in the nervous system and peripheral organs. One of the most well-studied effects of PACAP is its cytoprotective action, against different harmful stimuli in a wide variety of cells and tissues. PACAP occurs in the urinary system, from the kidney to the lower urinary tract. The present review focuses on the nephroprotective effects of PACAP and summarizes data obtained regarding the protective effects of PACAP in different models of kidney pathologies. In vitro data show that PACAP protects tubular cells against oxidative stress, myeloma light chain, cisplatin, cyclosporine-A and hypoxia. In vivo data provide evidence for its protective effects in ischemia/reperfusion, cisplatin, cyclosporine-A, myeloma kidney injury, diabetic nephropathy and gentamicin-induced kidney damage. Results accumulated on the renoprotective effects of PACAP suggest that PACAP is an emerging candidate for treatment of human kidney pathologies.
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Affiliation(s)
- Dora Reglodi
- Department of Anatomy, University of Pecs, Szigeti u 12, 7624 Pecs, Hungary.
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Nakamachi T, Matkovits A, Seki T, Shioda S. Distribution and protective function of pituitary adenylate cyclase-activating polypeptide in the retina. Front Endocrinol (Lausanne) 2012; 3:145. [PMID: 23189073 PMCID: PMC3504973 DOI: 10.3389/fendo.2012.00145] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP), which is found in 27- or 38-amino acid forms, belongs to the VIP/glucagon/secretin family. PACAP and its three receptor subtypes are expressed in neural tissues, with PACAP known to exert a protective effect against several types of neural damage. The retina is considered to be part of the central nervous system, and retinopathy is a common cause of profound and intractable loss of vision. This review will examine the expression and morphological distribution of PACAP and its receptors in the retina, and will summarize the current state of knowledge regarding the protective effect of PACAP against different kinds of retinal damage, such as that identified in association with diabetes, ultraviolet light, hypoxia, optic nerve transection, and toxins. This article will also address PACAP-mediated protective pathways involving retinal glial cells.
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Affiliation(s)
- Tomoya Nakamachi
- Department of Anatomy, Showa University School of MedicineTokyo, Japan
- Center for Biotechnology, Showa UniversityTokyo, Japan
| | - Attila Matkovits
- Department of Anatomy, Showa University School of MedicineTokyo, Japan
- Center for Biotechnology, Showa UniversityTokyo, Japan
| | - Tamotsu Seki
- Department of Anatomy, Showa University School of MedicineTokyo, Japan
- Center for Biotechnology, Showa UniversityTokyo, Japan
| | - Seiji Shioda
- Department of Anatomy, Showa University School of MedicineTokyo, Japan
- *Correspondence: Seiji Shioda, Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan. 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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Hori M, Nakamachi T, Rakwal R, Shibato J, Nakamura K, Wada Y, Tsuchikawa D, Yoshikawa A, Tamaki K, Shioda S. Unraveling the ischemic brain transcriptome in a permanent middle cerebral artery occlusion mouse model by DNA microarray analysis. Dis Model Mech 2011; 5:270-83. [PMID: 22015461 PMCID: PMC3291648 DOI: 10.1242/dmm.008276] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Brain ischemia, also termed cerebral ischemia, is a condition in which there is insufficient blood flow to the brain to meet metabolic demand, leading to tissue death (cerebral infarction) due to poor oxygen supply (cerebral hypoxia). Our group is interested in the protective effects of neuropeptides for alleviating brain ischemia, as well as the underlying mechanisms of their action. The present study was initiated to investigate molecular responses at the level of gene expression in ischemic brain tissue. To achieve this, we used a mouse permanent middle cerebral artery occlusion (PMCAO) model in combination with high-throughput DNA microarray analysis on an Agilent microarray platform. Briefly, the right (ipsilateral) and left (contralateral) hemispheres of PMCAO model mice were dissected at two time points, 6 and 24 hours post-ischemia. Total RNA from the ischemic (ipsilateral) hemisphere was subjected to DNA microarray analysis on a mouse whole genome 4x44K DNA chip using a dye-swap approach. Functional categorization using the gene ontology (GO, MGD/AMIGO) of numerous changed genes revealed expression pattern changes in the major categories of cellular process, biological regulation, regulation of biological process, metabolic process and response to stimulus. Reverse-transcriptase PCR (RT-PCR) analysis on randomly selected highly up- or downregulated genes validated, in general, the microarray data. Using two time points for this analysis, major and minor trends in gene expression and/or functions were observed in relation to early- and late-response genes and differentially regulated genes that were further classified into specific pathways or disease states. We also examined the expression of these genes in the contralateral hemisphere, which suggested the presence of bilateral effects and/or differential regulation. This study provides the first ischemia-related transcriptome analysis of the mouse brain, laying a strong foundation for studies designed to elucidate the mechanisms regulating ischemia and to explore the neuroprotective effects of agents such as target neuropeptides.
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Affiliation(s)
- Motohide Hori
- Department of Forensic Medicine and Molecular Pathology, School of Medicine, Kyoto University, Kyoto, Japan
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Szabadfi K, Atlasz T, Kiss P, Danyadi B, Tamas A, Helyes Z, Hashimoto H, Shintani N, Baba A, Toth G, Gabriel R, Reglodi D. Mice deficient in pituitary adenylate cyclase activating polypeptide (PACAP) are more susceptible to retinal ischemic injury in vivo. Neurotox Res 2011; 21:41-8. [PMID: 21717232 DOI: 10.1007/s12640-011-9254-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 06/14/2011] [Accepted: 06/16/2011] [Indexed: 12/19/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuroprotective peptide exerting protective effects in neuronal injuries. We have provided evidence that PACAP is neuroprotective in several models of retinal degeneration in vivo. Our previous studies showed that PACAP treatment ameliorated the damaging effects of chronic hypoperfusion modeled by permanent bilateral carotid artery occlusion. We have also demonstrated in earlier studies that treatment with PACAP antagonists further aggravates retinal lesions. It has been shown that PACAP deficient mice have larger infarct size in cerebral ischemia. The aim of this study was to compare the degree of retinal damage in wild type and PACAP deficient mice in ischemic retinal insult. Mice underwent 10 min of bilateral carotid artery occlusion followed by 2-week reperfusion period. Retinas were then processed for histological analysis. It was found that PACAP deficient mice had significantly greater retinal damage, as shown by the thickness of the whole retina, the morphometric analysis of the individual retinal layers, and the cell numbers in the inner nuclear and ganglion cell layers. Exogenous PACAP administration could partially protect against retinal degeneration in PACAP deficient mice. These results clearly show that endogenous PACAP reacts as a stress-response peptide that is necessary for endogenous protection against different retinal insults.
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Affiliation(s)
- K Szabadfi
- Department of Experimental Zoology, University of Pecs, Pecs, Hungary
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Dejda A, Seaborn T, Bourgault S, Touzani O, Fournier A, Vaudry H, Vaudry D. PACAP and a novel stable analog protect rat brain from ischemia: Insight into the mechanisms of action. Peptides 2011; 32:1207-16. [PMID: 21514338 DOI: 10.1016/j.peptides.2011.04.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 04/06/2011] [Accepted: 04/07/2011] [Indexed: 02/06/2023]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) shows potent protective effects in numerous models of neurological insults. However, the use of PACAP as a clinically efficient drug is limited by its poor metabolic stability. By combining identification of enzymatic cleavage sites with targeted chemical modifications, a metabolically stable and potent PACAP38 analog was recently developed. The neuroprotective activity of this novel compound was for the first time evaluated and compared to the native peptide using a rat model of middle cerebral artery occlusion (MCAO). Our results show that as low as picomolar doses of PACAP38 and its analog strongly reduce infarct volume and improve neurological impairment induced by stroke. In particular, these peptides inhibit the expression of Bcl-2-associated death promoter, caspase 3, macrophage inflammatory protein-1α, inducible nitric oxide synthase 2, tumor necrosis factor-α mRNAs, and increase extracellular signal-regulated kinase 2, B-cell CLL/lymphoma 2 and interleukin 6 mRNA levels. These results indicate that the neuroprotective effect of PACAP after MCAO is not only due to its ability to inhibit apoptosis but also to modulate the inflammatory response. The present study highlights the potential therapeutic efficacy of very low concentrations of PACAP or its metabolically stable derivative for the treatment of stroke.
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Szakaly P, Laszlo E, Kovacs K, Racz B, Horvath G, Ferencz A, Lubics A, Kiss P, Tamas A, Brubel R, Opper B, Baba A, Hashimoto H, Farkas J, Matkovits A, Magyarlaki T, Helyes Z, Reglodi D. Mice deficient in pituitary adenylate cyclase activating polypeptide (PACAP) show increased susceptibility to in vivo renal ischemia/reperfusion injury. Neuropeptides 2011; 45:113-21. [PMID: 21211837 DOI: 10.1016/j.npep.2010.12.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 11/12/2010] [Accepted: 12/07/2010] [Indexed: 11/29/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide with well-known cytoprotective effects. We have reported earlier that PACAP decreases mortality and the degree of tubular atrophy in a rat model of renal ischemia/reperfusion injury. Recently, we have shown that kidney cultures isolated from PACAP deficient mice show increased susceptibility to renal oxidative stress. Based on these previous studies, we raised the question whether PACAP deficient mice display increased sensitivity to in vivo kidney ischemia/reperfusion. PACAP⁻/⁻ mice underwent 45 or 60 min of renal ischemia followed by 2 weeks reperfusion. Kidneys were processed for histological analysis. Sections stained with PAS-haematoxylin were graded for the following parameters: degree of tubular dilation, Bowmann's capsule dilation, lymphocyte and macrophage infiltration, thyroidization and the disappearance of the PAS-positive glycocalyx from under the brush border. In other sets of experiments, tissue cytokine expression and the level of the endogenous antioxidant superoxide dismutase (SOD) were also determined after 60 min ischemia/reperfusion. Our results show that while intact kidneys were not different between wild-type and PACAP deficient mice, marked differences were observed in the histological structures in groups that underwent ischemia/reperfusion. PACAP deficient mice had a worse histological outcome, with significantly higher histological scores for all tested parameters. Cytokine expression was also markedly different between wild-type and PACAP deficient mice. In addition, the level of SOD was significantly lower in PACAP⁻/⁻ animals after ischemia/reperfusion. In conclusion, the lack of endogenous PACAP leads to higher susceptibility to in vivo renal ischemia/reperfusion, suggesting that PACAP has an endogenous renoprotective effect.
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Moody TW, Ito T, Osefo N, Jensen RT. VIP and PACAP: recent insights into their functions/roles in physiology and disease from molecular and genetic studies. Curr Opin Endocrinol Diabetes Obes 2011; 18:61-7. [PMID: 21157320 PMCID: PMC3075877 DOI: 10.1097/med.0b013e328342568a] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE OF REVIEW Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) as well as the three classes of G-protein-coupled receptors mediating their effects, are widely distributed in the central nervous system (CNS) and peripheral tissues. These peptides are reported to have many effects in different tissues, which are physiological or pharmacological, and which receptor mediates which effect, has been difficult to determine, primarily due to lack of potent, stable, selective agonists/antagonists. Recently the use of animals with targeted knockout of the peptide or a specific receptor has provided important insights into their role in normal physiology and disease states. RECENT FINDINGS During the review period, considerable progress and insights has occurred in the understanding of the role of VIP/PACAP as well as their receptors in a number of different disorders/areas. Particularly, insights into their roles in energy metabolism, glucose regulation, various gastrointestinal processes including gastrointestinal inflammatory conditions and motility and their role in the CNS as well as CNS diseases has greatly expanded. SUMMARY PACAP/VIP as well as their three classes of receptors are important in many physiological/pathophysiological processes, some of which are identified in these studies using knockout animals. These studies may lead to new novel treatment approaches. Particularly important are their roles in glucose metabolism and on islets leading to possible novel approaches in diabetes; their novel anti-inflammatory, cytoprotective effects, their CNS neuroprotective effects, and their possible roles in diseases such as schizophrenia and chronic depression.
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Affiliation(s)
- Terry W. Moody
- Department of Health and Human Services, National Cancer Institute Office of the Director, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Tetsuhide Ito
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan
| | - Nuramy Osefo
- Department of Health and Human Services, National Cancer Institute Office of the Director, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Robert T. Jensen
- Digestive Diseases Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
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Johanson C, Stopa E, Baird A, Sharma H. Traumatic brain injury and recovery mechanisms: peptide modulation of periventricular neurogenic regions by the choroid plexus-CSF nexus. J Neural Transm (Vienna) 2011; 118:115-33. [PMID: 20936524 PMCID: PMC3026679 DOI: 10.1007/s00702-010-0498-0] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2010] [Accepted: 09/24/2010] [Indexed: 01/26/2023]
Abstract
In traumatic brain injury (TBI), severe disruptions occur in the choroid plexus (CP)-cerebrospinal fluid (CSF) nexus that destabilize the nearby hippocampal and subventricular neurogenic regions. Following invasive and non-invasive injuries to cortex, several adverse sequelae harm the brain interior: (i) structural damage to CP epithelium that opens the blood-CSF barrier (BCSFB) to protein, (ii) altered CSF dynamics and intracranial pressure (ICP), (iii) augmentation of leukocyte traffic across CP into the CSF-brain, (iv) reduction in CSF sink action and clearance of debris from ventricles, and (v) less efficient provision of micronutritional and hormonal support for the CNS. However, gradual post-TBI restitution of the injured CP epithelium and ependyma, and CSF homeostatic mechanisms, help to restore subventricular/subgranular neurogenesis and the cognitive abilities diminished by CNS damage. Recovery from TBI is facilitated by upregulated choroidal/ependymal growth factors and neurotrophins, and their secretion into ventricular CSF. There, by an endocrine-like mechanism, CSF bulk flow convects the neuropeptides to target cells in injured cortex for aiding repair processes; and to neurogenic niches for enhancing conversion of stem cells to new neurons. In the recovery from TBI and associated ischemia, the modulating neuropeptides include FGF2, EGF, VEGF, NGF, IGF, GDNF, BDNF, and PACAP. Homeostatic correction of TBI-induced neuropathology can be accelerated or amplified by exogenously boosting the CSF concentration of these growth factors and neurotrophins. Such intraventricular supplementation via the CSF route promotes neural restoration through enhanced neurogenesis, angiogenesis, and neuroprotective effects. CSF translational research presents opportunities that involve CP and ependymal manipulations to expedite recovery from TBI.
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Affiliation(s)
- Conrad Johanson
- Department of Neurosurgery, Warren Alpert Medical School at Brown University, Providence, RI 02903, USA.
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Nakamachi T, Nakamura K, Oshida K, Kagami N, Mori H, Watanabe J, Arata S, Yofu S, Endo K, Wada Y, Hori M, Tsuchikawa D, Kato M, Shioda S. Pituitary adenylate cyclase-activating polypeptide (PACAP) stimulates proliferation of reactive astrocytes in vitro. J Mol Neurosci 2010; 43:16-21. [PMID: 20574684 DOI: 10.1007/s12031-010-9404-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 05/10/2010] [Indexed: 10/19/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide originally isolated from ovine hypothalamus. Recently, we have shown that the PACAP receptor (PAC1-R) is expressed in reactive astrocytes following an in vivo stub wound brain injury. However, the functional role of PACAP has not yet been clarified. In order to investigate the effect of PACAP on the proliferation of reactive astrocytes, a scratch wound paradigm was applied to astrocytic monolayers. Following injury, there was an increase in PAC1-R and glial fibrillary acidic protein (GFAP) immunoreactivity in the astrocytes surrounding the scratch line. PACAP at concentrations of 10(-15) to 10(-7) M was applied immediately after scratching, and the proliferating astrocytes were visualized by multiple immunofluorescence labeling. The percentage of cells that colabeled for Ki67 (a marker of proliferating cells) and GFAP increased in the 10(-11)- and 10(-13)-M PACAP-treated groups. The proliferating astrocytes induced by PACAP treatment mainly occurred in the proximal wound area where many reactive astrocytes were observed. Pretreatment with the PACAP receptor antagonist PACAP6-38 significantly suppressed the PACAP-induced effects. These results strongly suggest that PACAP plays an important role in the proliferation of reactive astrocytes following nerve injury.
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Affiliation(s)
- Tomoya Nakamachi
- Department of Anatomy, School of Medicine, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
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Atlasz T, Szabadfi K, Kiss P, Marton Z, Griecs M, Hamza L, Gaal V, Biro Z, Tamas A, Hild G, Nyitrai M, Toth G, Reglodi D, Gabriel R. Effects of PACAP in UV-A radiation-induced retinal degeneration models in rats. J Mol Neurosci 2010; 43:51-7. [PMID: 20521124 DOI: 10.1007/s12031-010-9392-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2010] [Accepted: 05/11/2010] [Indexed: 11/26/2022]
Abstract
The retina is constantly exposed to ultraviolet (UV) light with different wavelengths, which may lead to chronic UV-induced retinal injury. In our previous studies, we have shown the protective effects of pituitary adenylate cyclase activating polypeptide (PACAP) in toxic and ischemic retinal injuries. The aim of the present study was to investigate the effects of PACAP in UV-A-induced retinal lesion. We used diffuse UV-A radiation (315-400 nm) to induce acute retinal damage over a short period of exposure. Using standard histological (morphological and morphometrical) analysis, we assessed the actions of intravitreal PACAP (100 pmol/5 µl) treatment on acute UV-A-induced retinal damage. We measured the thickness of nuclear and plexiform layers as well as the number of cells in the outer nuclear and inner nuclear layers and in the ganglion cell layer. Outer limiting membrane-inner limiting membrane distances in the cross-section of the retina were also examined. Our results show that UV-A light-induced retinal damage led to severe degeneration in the photoreceptor layer, and in the outer and inner nuclear layers. Alteration in the plexiform layers was also observed. We found that post-irradiation PACAP treatment significantly attenuated the UV-A-induced retinal damage. Our results provide the basis for future clinical application of PACAP treatment in retinal degeneration and may have clinical implications in several ophthalmic diseases.
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Affiliation(s)
- Tamas Atlasz
- Department of Sportbiology, University of Pecs, Pecs, Hungary
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