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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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53
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Emery AC, Eiden LE. Signaling through the neuropeptide GPCR PAC₁ induces neuritogenesis via a single linear cAMP- and ERK-dependent pathway using a novel cAMP sensor. FASEB J 2012; 26:3199-211. [PMID: 22532442 DOI: 10.1096/fj.11-203042] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Both cAMP and ERK are necessary for neuroendocrine cell neuritogenesis, and pituitary adenylate cyclase-activating polypeptide (PACAP) activates each. It is important to know whether cAMP and ERK are arranged in a novel, linear pathway or in two parallel pathways using known signaling mechanisms. Native cellular responses [cAMP elevation, ERK phosphorylation, cAMP responsive element binding (CREB) phosphorylation, and neuritogenesis] and promoter-reporter gene activation after treatment with forskolin, cAMP analogs, and PACAP were measured in Neuroscreen-1 (NS-1) cells, a PC12 variant enabling simultaneous morphological, molecular biological, and biochemical analysis. Forskolin (25 μM) and cAMP analogs (8-bromo-cAMP, dibutyryl-cAMP, and 8-chlorophenylthio-cAMP) stimulated ERK phosphorylation and neuritogenesis in NS-1 cells. Both ERK phosphorylation and neuritogenesis were MEK dependent (blocked by 10 μM U0126) and PKA independent (insensitive to 30 μM H-89 or 100 nM myristoylated protein kinase A inhibitor). CREB phosphorylation induced by PACAP was blocked by H-89. The exchange protein activated by cAMP (Epac)-selective 8-(4-chlorophenylthio)-2'-O-Me-cAMP (100-500 μM) activated Rap1 without affecting the other cAMP-dependent processes. Thus, PACAP-38 potently stimulated two distinct and independent cAMP pathways leading to CREB or ERK activation in NS-1 cells. Drug concentrations for appropriate effect were derived from control data for all compounds. In summary, a novel PKA- and Epac-independent signaling pathway: PACAP → adenylate cyclase → cAMP → ERK → neuritogenesis has been identified.
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Affiliation(s)
- Andrew C Emery
- Section on Molecular Neuroscience, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, Bethesda, Maryland 20892-4090, USA
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54
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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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55
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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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56
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Shi GX, Andres DA, Cai W. Ras family small GTPase-mediated neuroprotective signaling in stroke. Cent Nerv Syst Agents Med Chem 2012; 11:114-37. [PMID: 21521171 DOI: 10.2174/187152411796011349] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 01/18/2011] [Accepted: 03/22/2011] [Indexed: 12/31/2022]
Abstract
Selective neuronal cell death is one of the major causes of neuronal damage following stroke, and cerebral cells naturally mobilize diverse survival signaling pathways to protect against ischemia. Importantly, therapeutic strategies designed to improve endogenous anti-apoptotic signaling appear to hold great promise in stroke treatment. While a variety of complex mechanisms have been implicated in the pathogenesis of stroke, the overall mechanisms governing the balance between cell survival and death are not well-defined. Ras family small GTPases are activated following ischemic insults, and in turn, serve as intrinsic switches to regulate neuronal survival and regeneration. Their ability to integrate diverse intracellular signal transduction pathways makes them critical regulators and potential therapeutic targets for neuronal recovery after stroke. This article highlights the contribution of Ras family GTPases to neuroprotective signaling cascades, including mitogen-activated protein kinase (MAPK) family protein kinase- and AKT/PKB-dependent signaling pathways as well as the regulation of cAMP response element binding (CREB), Forkhead box O (FoxO) and hypoxiainducible factor 1(HIF1) transcription factors, in stroke.
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Affiliation(s)
- Geng-Xian Shi
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, 741 S. Limestone St., Lexington, KY 40536-0509, USA.
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57
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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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58
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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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59
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Mansouri S, Ortsäter H, Pintor Gallego O, Darsalia V, Sjöholm A, Patrone C. Pituitary adenylate cyclase-activating polypeptide counteracts the impaired adult neural stem cell viability induced by palmitate. J Neurosci Res 2011; 90:759-68. [PMID: 22183970 DOI: 10.1002/jnr.22803] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 08/30/2011] [Indexed: 12/30/2022]
Abstract
Diabetes and obesity are characterized by hyperlipidemia and represent risk factors for premature neurological disorders. Diabetic/obese animals have impaired adult neurogenesis. We hypothesize that lipotoxicity leading to neurogenesis impairment plays a role in the development of neurological complications. If so, normalizing neurogenesis in diabetes/obesity could be therapeutically useful in counteracting neurological dysfunction. The goal of this study was to determine the potential of pituitary adenylate cyclase-activating polypeptide (PACAP) to protect adult neural stem cells (NSCs) from lipotoxicity and to study the expression of PACAP receptors in NSCs under lipotoxic conditions in vitro and in the subventricular zone in vivo. The viability of NSCs isolated from the adult mouse brain subventricular zone was assessed in the presence of a high-fat milieu, as mimicked by palmitate, which characterizes diabetic lipotoxicity. Regulation studies of PACAP receptors were performed by quantitative PCR on NSCs in vitro or on subventricular tissues isolated from obese ob/ob mice and their lean littermates. We show that palmitate impairs NSC viability by promoting lipoapoptosis. We also show that PACAP counteracts lipotoxicity via PAC-1 receptor activation. Studies on PACAP receptor expression revealed that PAC-1 and VPAC-2 are expressed by NSC in vitro and are upregulated by palmitate treatment and that PAC-1, VPAC-1, and VPAC-2 are expressed in the subventricular zone/striatum in vivo and are upregulated in ob/ob mice. The present study reveals a previously uncharacterized role of PACAP to protect NSC from lipotoxicity and suggests a potential therapeutic role for PACAP receptor agonists in the treatment of neurological complications in obesity and diabetes.
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Affiliation(s)
- Shiva Mansouri
- Diabetes Research Unit, Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
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60
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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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61
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Holighaus Y, Mustafa T, Eiden LE. PAC1hop, null and hip receptors mediate differential signaling through cyclic AMP and calcium leading to splice variant-specific gene induction in neural cells. Peptides 2011; 32:1647-55. [PMID: 21693142 PMCID: PMC3163081 DOI: 10.1016/j.peptides.2011.06.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 06/05/2011] [Accepted: 06/06/2011] [Indexed: 11/19/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP)-mediated activation of its G protein-coupled receptor PAC1 results in activation of the two G proteins Gs and Gq to alter second messenger generation and gene transcription in the nervous system, important for homeostatic responses to stress and injury. Heterologous expression of the three major splice variants of the rat PAC1 receptor, PAC1hop, null and hip, in neural NG108-15 cells conferred PACAP-mediated intracellular cAMP generation, while elevation of [Ca(2+)](i) occurred only in PAC1hop-, and to a lesser extent in PAC1null-expressing cells. Induction of vasoactive intestinal polypeptide (VIP) and stanniocalcin 1 (STC1), two genes potentially involved in PACAP's homeostatic responses, was examined as a function of the expressed PAC1 variant. VIP induction was greatest in PAC1hop-expressing cells, suggesting that a maximal transcriptional response requires combinatorial signaling through both cAMP and Ca(2+). STC1 induction was similar for all three receptor splice variants and was mimicked by the adenylate cyclase activator forskolin, indicating that cAMP elevation is sufficient to induce STC1. The degree of activation of two different second messenger pathways appears to determine the transcriptional response, suggesting that cellular responses to stressors are fine-tuned through differential receptor isoform expression. Signaling to the VIP gene proceeded through cAMP and protein kinase A (PKA) in these cells, independently of the MAP kinase ERK1/2. STC1 gene induction by PACAP was dependent on cAMP and ERK1/2, independently of PKA. Differential gene induction via different cAMP dependent signaling pathways potentially provides further targets for the design of treatments for stress-associated disorders.
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Affiliation(s)
- Yvonne Holighaus
- Section on Molecular Neuroscience, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, Bethesda, MD 20892, USA
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62
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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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63
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Vincze A, Reglodi D, Helyes Z, Hashimoto H, Shintani N, Abrahám H. Role of endogenous pituitary adenylate cyclase activating polypeptide (PACAP) in myelination of the rodent brain: lessons from PACAP-deficient mice. Int J Dev Neurosci 2011; 29:923-35. [PMID: 21726625 DOI: 10.1016/j.ijdevneu.2011.06.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 06/01/2011] [Accepted: 06/18/2011] [Indexed: 11/26/2022] Open
Abstract
Pituitary adenylate-cyclase activator polypeptide (PACAP), as a consequence of its effect on the elevation of intracellular cAMP level, strongly influences brain development including myelination. While proliferation of oligodendroglial progenitors is stimulated by PACAP applied in vitro, their differentiation is inhibited. However, the in vivo role of PACAP on myelination has never been examined. In the present study the role of endogenous PACAP in myelination was examined in PACAP-deficient mice, in several areas of the brain with a special attention to the cerebral cortex. In young postnatal and adult mice myelination was studied with immunohistochemistry detecting a protein present in the myelin sheath, the myelin basic protein, with Luxol Fast Blue staining and with electron microscopy. Results obtained in PACAP-deficient mice were compared to age-matched wild type controls. We found that the sequence of myelination in the PACAP-deficient animals was similar to that observed in controls. According to this, in both PACAP-deficient and wild type mice, the somatosensory cortex was myelinated before motor areas that preceded the myelination of associational cortical areas. Archicortical associational areas such as the cingulate cortex were myelinated before neocortical areas. Myelination in the corpus callosum followed the known rostro-caudal direction in both PACAP-deficient and wild type animals, and the ventrolateral part of the corpus callosum was myelinated earlier than the dorsomedial part in both groups. In contrast to the similarity in its sequence, striking difference was found in the onset of myelination that started earlier in PACAP-deficient mice than in wild type controls in all of the examined brain regions, including cerebral archi- and neocortex. The first myelinated axons in each of the examined brain regions were observed earlier in the PACAP-deficient mice than in controls. When age-matched animals of the two groups were compared, density of myelinated fibers in the PACAP-deficient mice was higher than in controls in all of the examined areas. We propose that endogenous PACAP exerts an inhibitory role on myelination in vivo. Since myelin sheath of the central nervous system contains several factors blocking neurite outgrowth, inhibition of myelination by PACAP gives time for axonal development and synapse formation, and therefore, strengthens neuronal plasticity.
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Affiliation(s)
- András Vincze
- Central Electron Microscopic Laboratory, University of Pécs Medical School, Pécs, Hungary
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64
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Baxter PS, Martel MA, McMahon A, Kind PC, Hardingham GE. Pituitary adenylate cyclase-activating peptide induces long-lasting neuroprotection through the induction of activity-dependent signaling via the cyclic AMP response element-binding protein-regulated transcription co-activator 1. J Neurochem 2011; 118:365-78. [PMID: 21623792 PMCID: PMC3557719 DOI: 10.1111/j.1471-4159.2011.07330.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Pituitary adenylate cyclase-activating peptide (PACAP) is a neuroprotective peptide which exerts its effects mainly through the cAMP-protein kinase A (PKA) pathway. Here, we show that in cortical neurons, PACAP-induced PKA signaling exerts a major part of its neuroprotective effects indirectly, by triggering action potential (AP) firing. Treatment of cortical neurons with PACAP induces a rapid and sustained PKA-dependent increase in AP firing and associated intracellular Ca2+ transients, which are essential for the anti-apoptotic actions of PACAP. Transient exposure to PACAP induces long-lasting neuroprotection in the face of apoptotic insults which is reliant on AP firing and the activation of cAMP response element (CRE) binding protein (CREB)-mediated gene expression. Although direct, activity-independent PKA signaling is sufficient to trigger phosphorylation on CREB’s activating serine-133 site, this is insufficient for activation of CREB-mediated gene expression. Full activation is dependent on CREB-regulated transcription co-activator 1 (CRTC1), whose PACAP-induced nuclear import is dependent on firing activity-dependent calcineurin signaling. Over-expression of CRTC1 is sufficient to rescue PACAP-induced CRE-mediated gene expression in the face of activity-blockade, while dominant negative CRTC1 interferes with PACAP-induced, CREB-mediated neuroprotection. Thus, the enhancement of AP firing may play a significant role in the neuroprotective actions of PACAP and other adenylate cyclase-coupled ligands.
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Affiliation(s)
- Paul S Baxter
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
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65
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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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66
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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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67
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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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Shneider Y, Shtrauss Y, Yadid G, Pinhasov A. Differential expression of PACAP receptors in postnatal rat brain. Neuropeptides 2010; 44:509-14. [PMID: 20971507 DOI: 10.1016/j.npep.2010.09.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Revised: 09/13/2010] [Accepted: 09/14/2010] [Indexed: 12/22/2022]
Abstract
Pituitary Adenylate Cyclase Activating Polypeptide (PACAP) is a multi-functional neuropeptide that acts through activation of three common G-protein coupled receptors (VPAC1, VPAC2 and PAC1). In this study, we have investigated the gene expression profile of PAC1 isoforms (Hop1, Hip, Hip-Hop) and VPAC1, VPAC2 receptors in distinct brain regions during different stages of rat postnatal development. Using quantitative real time PCR approach we found that PAC1 isoforms were highly expressed in the cortex of newborns with marked decrease in expression during later stages of development. In contrast, mRNA levels of VPAC1, VPAC2 receptors were markedly lower in newborns in comparison to later developmental stages. Expression of PAC1 isoforms predominated in the hippocampus, while expression of VPAC1 was more prominent in the cortex and VPAC2 in the striatum and hippocampus. In addition we found that during early stages of postnatal development the expression of PAC1 receptor in the hippocampus was significantly higher in females than in males. No sex dependent differences in expression were observed for the VPAC1 and VPAC2 receptors. In summary, differential expression of PAC1, VPAC1 and VPAC2 receptors during postnatal development as well as gender dependent differences of PAC1 receptor expression in the hippocampus, will contribute to our understanding of the role of PACAP/VIP signaling system in normal brain development and function.
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Affiliation(s)
- Yevgenia Shneider
- Department of Molecular Biology, Ariel University Center of Samaria, Ariel, Israel
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69
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Atlasz T, Szabadfi K, Kiss P, Racz B, Gallyas F, Tamas A, Gaal V, Marton Z, Gabriel R, Reglodi D. Pituitary adenylate cyclase activating polypeptide in the retina: focus on the retinoprotective effects. Ann N Y Acad Sci 2010; 1200:128-39. [PMID: 20633141 DOI: 10.1111/j.1749-6632.2010.05512.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a neurotrophic and neuroprotective peptide that has been shown to exert protective effects against different neuronal injuries, such as traumatic brain and spinal cord injury, models of neurodegenerative diseases, and cerebral ischemia. PACAP and its receptors are present in the retina. In this study, we summarize the current knowledge on retinal PACAP with focus on the retinoprotective effects. Results of histological, immunohistochemical, and molecular biological analysis are reviewed. In vitro, PACAP shows protection against glutamate, thapsigargin, anisomycin, and anoxia. In vivo, the protective effects of intravitreal PACAP treatment have been shown in the following models of retinal degeneration in rats: excitotoxic injury induced by glutamate and kainate, ischemic injury, degeneration caused by UV-A light, optic nerve transection, and streptozotocin-induced diabetic retinopathy. Studying the molecular mechanism has revealed that PACAP acts by activating antiapoptotic and inhibiting proapoptotic signaling pathways in the retina in vivo. These studies strongly suggest that PACAP is an excellent candidate retinoprotective agent that could be a potential therapeutic substance in various retinal diseases.
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Affiliation(s)
- T Atlasz
- Department of Sportbiology, University of Pecs, Pecs, Hungary
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70
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Mester L, Kovacs K, Racz B, Solti I, Atlasz T, Szabadfi K, Tamas A, Reglodi D. Pituitary Adenylate Cyclase-Activating Polypeptide is Protective Against Oxidative Stress in Human Retinal Pigment Epithelial Cells. J Mol Neurosci 2010; 43:35-43. [DOI: 10.1007/s12031-010-9427-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Accepted: 07/07/2010] [Indexed: 12/27/2022]
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71
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Horvath G, Racz B, Szakaly P, Kiss P, Laszlo E, Hau L, Tamas A, Helyes Z, Lubics A, Hashimoto H, Baba A, Reglodi D. Mice Deficient in Neuropeptide PACAP Demonstrate Increased Sensitivity to In Vitro Kidney Hypoxia. Transplant Proc 2010; 42:2293-5. [DOI: 10.1016/j.transproceed.2010.05.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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72
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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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73
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The role of PACAP in central cardiorespiratory regulation. Respir Physiol Neurobiol 2010; 174:65-75. [PMID: 20470908 DOI: 10.1016/j.resp.2010.05.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 05/03/2010] [Accepted: 05/03/2010] [Indexed: 11/22/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) plays a role in almost every biological process from reproduction to hippocampal function. One area where a role for PACAP is not clearly delineated is central cardiorespiratory regulation. PACAP and its receptors (PAC1, VPAC1 and VPAC2) are present in cardiovascular areas of the ventral medulla and spinal cord and in the periphery. Central administration of PACAP generally increases arterial pressure. Knowledge about the role of PACAP in central cardiovascular regulation is growing, but even less is known about PACAP in central respiratory regulation. No specific data is currently available regarding the presence of PACAP or receptors in key respiratory centers, although it is known that neonatal PACAP knock-out mice die suddenly in a manner similar to sudden infant death syndrome (SIDS). Future studies in mature preparations investigating the role of PACAP in the physiology and integration of central cardiorespiratory reflexes are clearly essential for a full understanding of this important neuropeptide in breathing.
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74
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Kemény Á, Reglődi D, Cseharovszky R, Hashimoto H, Baba A, Szolcsányi J, Pintér E, Helyes Z. Pituitary Adenylate Cyclase-Activating Polypeptide Deficiency Enhances Oxazolone-Induced Allergic Contact Dermatitis in Mice. J Mol Neurosci 2010; 42:443-9. [DOI: 10.1007/s12031-010-9368-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Accepted: 04/07/2010] [Indexed: 12/18/2022]
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75
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Comparison of intestinal warm ischemic injury in PACAP knockout and wild-type mice. J Mol Neurosci 2010; 42:435-42. [PMID: 20387008 DOI: 10.1007/s12031-010-9357-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2010] [Accepted: 03/19/2010] [Indexed: 10/19/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is present in the gastrointestinal tract and plays a central role in the intestinal physiology, mainly in the secretion and motility. The aim of our study was to compare the ischemic injury in wild-type and PACAP-38 knockout mice following warm mesenteric small bowel ischemia. Warm ischemia groups were designed with occlusion of superior mesenteric artery for 1, 3, and 6 h in wild-type (n = 10 in each group) and PACAP-38 knockout (n = 10 in each group) mice. Small bowel biopsies were collected after laparotomy (control) and at the end of the ischemia periods. To determine oxidative stress parameters, malondialdehyde (MDA), reduced glutathione (GSH), and superoxide dismutase (SOD) were measured. Tissue damage was analyzed by qualitative and quantitative methods on hematoxylin/eosin-stained sections. In PACAP-38 knockout animals, tissue MDA increased significantly after 3 and 6 h ischemia (133.97 ± 6,2; 141.86 ± 5,8) compared to sham-operated (100.92 ± 3,6) and compared to wild-type results (112.8 ± 2,1; 118.4 ± 1.03 μmol/g, p < 0.05). Meanwhile, tissue concentration of GSH and activity of SOD decreased significantly in knockout mice compared to wild-type form (GSH, 795.97 ± 10.4; 665.1 ± 8,8 vs. 893.23 ± μmol/g; SOD, 94.4 ± 1.4; 81.2 ± 3.9 vs. 208.09 ± 3,7 IU/g). Qualitative and quantitative histological results showed destruction of the mucous, submucous layers, and crypts in knockout mice compared to wild-type tissues. These processes correlated with the warm ischemia periods. Our present results propose an important protective effect of endogenous PACAP-38 against intestinal warm ischemia, which provides basis for further investigation to elucidate the mechanism of this protective effect.
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76
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Ohtaki H, Satoh A, Nakamachi T, Yofu S, Dohi K, Mori H, Ohara K, Miyamoto K, Hashimoto H, Shintani N, Baba A, Matsunaga M, Shioda S. Regulation of Oxidative Stress by Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Mediated by PACAP Receptor. J Mol Neurosci 2010; 42:397-403. [DOI: 10.1007/s12031-010-9350-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Accepted: 03/09/2010] [Indexed: 11/28/2022]
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77
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Ferencz A, Weber G, Helyes Z, Hashimoto H, Baba A, Reglodi D. Presence of Endogenous PACAP-38 Ameliorated Intestinal Cold Preservation Tissue Injury. J Mol Neurosci 2010; 42:428-34. [DOI: 10.1007/s12031-010-9352-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2010] [Accepted: 03/12/2010] [Indexed: 10/19/2022]
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78
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Horvath G, Racz B, Reglodi D, Kovacs K, Kiss P, Gallyas F, Bognar Z, Szabo A, Magyarlaki T, Laszlo E, Lubics A, Tamas A, Toth G, Szakaly P. Effects of PACAP on mitochondrial apoptotic pathways and cytokine expression in rats subjected to renal ischemia/reperfusion. J Mol Neurosci 2010; 42:411-8. [PMID: 20229361 DOI: 10.1007/s12031-010-9342-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Accepted: 02/11/2010] [Indexed: 10/19/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide with highly efficient cytoprotective actions. Its neuroprotective effects are well-known, but PACAP is able to exert similar actions in non-neuronal cells. Recently, we have shown that PACAP prolongs renal ischemic time, decreases mortality, and attenuates tubular degeneration in a rat model of renal ischemia/reperfusion, but the mechanism of renoprotection is not yet known. Therefore, the aim of the present study was to obtain further insight into the renoprotective effects of PACAP by examining its direct effects of PACAP on mitochondrial permeability transition in vitro and on the expression of the anti-apoptotic Bcl-2 and cytokines/chemokines in kidney tissues following 45 and 60 min renal ischemia and reperfusion in vivo. We found that PACAP did not have any direct effect on mitochondrial permeability transition. Cytokine array revealed that the expression of a few cytokines/chemokines was strongly increased after ischemia/reperfusion, which was ameliorated by PACAP treatment. Furthermore, in rats subjected to renal ischemia, PACAP treatment counteracted the ischemia/reperfusion-induced decrease of the anti-apoptotic Bcl-2, both after 45 and 60 min ischemia, as analyzed by Western blot. In summary, we showed that PACAP could attenuate tissue injury involving both anti-inflammatory and anti-apoptotic effects, but not directly acting on mitochondrial permeability transition.
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Affiliation(s)
- Gabriella Horvath
- Department of Anatomy, School of Medicine, University of Pecs, Szigeti u 12, Pecs, Hungary.
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79
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Szabadfi K, Mester L, Reglodi D, Kiss P, Babai N, Racz B, Kovacs K, Szabo A, Tamas A, Gabriel R, Atlasz T. Novel neuroprotective strategies in ischemic retinal lesions. Int J Mol Sci 2010; 11:544-561. [PMID: 20386654 PMCID: PMC2852854 DOI: 10.3390/ijms11020544] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 01/27/2010] [Accepted: 01/27/2010] [Indexed: 02/04/2023] Open
Abstract
Retinal ischemia can be effectively modeled by permanent bilateral common carotid artery occlusion, which leads to chronic hypoperfusion-induced degeneration in the entire rat retina. The complex pathways leading to retinal cell death offer a complex approach of neuroprotective strategies. In the present review we summarize recent findings with different neuroprotective candidate molecules. We describe the protective effects of intravitreal treatment with: (i) urocortin 2; (ii) a mitochondrial ATP-sensitive K+ channel opener, diazoxide; (iii) a neurotrophic factor, pituitary adenylate cyclase activating polypeptide; and (iv) a novel poly(ADP-ribose) polymerase inhibitor (HO3089). The retinoprotective effects are demonstrated with morphological description and effects on apoptotic pathways using molecular biological techniques.
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Affiliation(s)
- Krisztina Szabadfi
- Department of Experimental Zoology and Neurobiology, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(K.S.);
(N.B.);
(R.G.)
| | - Laszlo Mester
- Department of Biochemistry and Medical Chemistry, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(L.M.);
(B.R.);
(K.K.);
(A.S.)
| | - Dora Reglodi
- Department of Anatomy, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(D.R.);
(P.K.);
(A.T.)
| | - Peter Kiss
- Department of Anatomy, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(D.R.);
(P.K.);
(A.T.)
| | - Norbert Babai
- Department of Experimental Zoology and Neurobiology, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(K.S.);
(N.B.);
(R.G.)
| | - Boglarka Racz
- Department of Biochemistry and Medical Chemistry, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(L.M.);
(B.R.);
(K.K.);
(A.S.)
| | - Krisztina Kovacs
- Department of Biochemistry and Medical Chemistry, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(L.M.);
(B.R.);
(K.K.);
(A.S.)
| | - Aliz Szabo
- Department of Biochemistry and Medical Chemistry, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(L.M.);
(B.R.);
(K.K.);
(A.S.)
| | - Andrea Tamas
- Department of Anatomy, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(D.R.);
(P.K.);
(A.T.)
| | - Robert Gabriel
- Department of Experimental Zoology and Neurobiology, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(K.S.);
(N.B.);
(R.G.)
| | - Tamas Atlasz
- Department of Experimental Zoology and Neurobiology, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(K.S.);
(N.B.);
(R.G.)
- Department of Sportbiology, University of Pecs, H-7624 Pecs, Hungary
- Author to whom correspondence should be addressed; E-Mail:
; Tel.: +36-72-503-600/4613; Fax: +36-72-501-517
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80
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Apurinic/apyrimidinic endonuclease APE1 is required for PACAP-induced neuroprotection against global cerebral ischemia. Proc Natl Acad Sci U S A 2010; 107:3204-9. [PMID: 20133634 DOI: 10.1073/pnas.1000030107] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Inducible DNA repair via the base-excision repair pathway is an important prosurvival mechanism activated in response to oxidative DNA damage. Elevated levels of the essential base-excision repair enzyme apurinic/apyrimidinic endonuclease 1 (APE1)/redox effector factor-1 correlate closely with neuronal survival against ischemic insults, depending on the CNS region, protective treatments, and degree of insult. However, the precise mechanisms by which this multifunctional protein affords protection and is activated by upstream signaling pathways in postischemic neurons are not well delineated. Here we show that intracerebral administration of pituitary adenylate cyclase-activating polypeptide (PACAP), an endogenously occurring small neuropeptide, induces expression of APE1 in hippocampal neurons. Induction of APE1 expression requires PKA- and p38-dependent phosphorylation of cAMP response-element binding and activating transcription factor 2, which leads to transactivation of the APE1 promoter. We further show that PACAP markedly reduces oxidative DNA stress and hippocampal CA1 neuronal death following transient global ischemia. These effects occurred, at least in part, via enhanced APE1 expression. Furthermore, the DNA repair function of APE1 was required for PACAP-mediated neuroprotection. Thus, induction of DNA repair enzymes may be a unique strategy for neuroprotection against hippocampal injury.
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81
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Mori H, Nakamachi T, Ohtaki H, Yofu S, Sato A, Endo K, Iso Y, Suzuki H, Takeyama Y, Shintani N, Hashimoto H, Baba A, Shioda S. Cardioprotective Effect of Endogenous Pituitary Adenylate Cyclase-Activating Polypeptide on Doxorubicin-Induced Cardiomyopathy in Mice. Circ J 2010; 74:1183-90. [DOI: 10.1253/circj.cj-09-1024] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Hiroyoshi Mori
- Division of Cardiology, Department of Internal Medicine, Showa University Fujigaoka Hospital
- Department of First Anatomy, Showa University School of Medicine
| | - Tomoya Nakamachi
- Department of First Anatomy, Showa University School of Medicine
- Center for Biotechnology, Showa University
| | - Hirokazu Ohtaki
- Department of First Anatomy, Showa University School of Medicine
| | - Sachiko Yofu
- Department of First Anatomy, Showa University School of Medicine
| | - Atsushi Sato
- Department of First Anatomy, Showa University School of Medicine
| | - Kimi Endo
- Department of First Anatomy, Showa University School of Medicine
| | - Yoshitaka Iso
- Division of Cardiology, Department of Internal Medicine, Showa University Fujigaoka Hospital
| | - Hiroshi Suzuki
- Division of Cardiology, Department of Internal Medicine, Showa University Fujigaoka Hospital
| | - Youichi Takeyama
- Division of Cardiology, Department of Internal Medicine, Showa University Fujigaoka Hospital
| | - Norihito Shintani
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University
| | - Hitoshi Hashimoto
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University
| | - Akemichi Baba
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University
| | - Seiji Shioda
- Department of First Anatomy, Showa University School of Medicine
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82
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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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83
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Horvath G, Mark L, Brubel R, Szakaly P, Racz B, Kiss P, Tamas A, Helyes Z, Lubics A, Hashimoto H, Baba A, Shintani N, Furjes G, Nemeth J, Reglodi D. Mice deficient in pituitary adenylate cyclase activating polypeptide display increased sensitivity to renal oxidative stress in vitro. Neurosci Lett 2009; 469:70-4. [PMID: 19932736 DOI: 10.1016/j.neulet.2009.11.046] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 11/13/2009] [Accepted: 11/17/2009] [Indexed: 12/24/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a multifunctional neuropeptide, showing widespread occurrence in the nervous system and also in peripheral organs. The neuroprotective effects of PACAP are well-established in different neuronal systems against noxious stimuli in vitro and in vivo. Recently, its general cytoprotective actions have been recognized, including renoprotective effects. However, the effect of endogenous PACAP in the kidneys is not known. The main aim of the present study was to investigate whether the lack of this endogenous neuropeptide influences survival of kidney cells against oxidative stress. First, we determined the presence of endogenous PACAP from mouse kidney homogenates by mass spectrometry and PACAP-like immunoreactivity by radioimmunoassay. Second, primary cultures were isolated from wild type and PACAP deficient mice and cell viability was assessed following oxidative stress induced by 0.5, 1.5 and 3mM H(2)O(2). Our mass spectrometry and radioimmunoassay results show that PACAP is endogenously present in the kidney. The main part of our study revealed that the sensitivity of cells from PACAP deficient mice was increased to oxidative stress: both after 2 or 4h of exposure, cell viability was significantly reduced compared to that from control wild type mice. This increased sensitivity of kidneys from PACAP deficient mice could be counteracted by exogenously given PACAP38. These results show, for the first time, that endogenous PACAP protects against oxidative stress in the kidney, and that PACAP may act as a stress sensor in renal cells. These findings further support the general cytoprotective nature of this neuropeptide.
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Atlasz T, Szabadfi K, Kiss P, Tamas A, Toth G, Reglodi D, Gabriel R. Evaluation of the protective effects of PACAP with cell-specific markers in ischemia-induced retinal degeneration. Brain Res Bull 2009; 81:497-504. [PMID: 19751807 DOI: 10.1016/j.brainresbull.2009.09.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2009] [Accepted: 09/08/2009] [Indexed: 01/26/2023]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a neurotrophic and neuroprotective peptide that has been shown to exert protective effects in different neuronal injuries, such as traumatic brain injury, models of neurodegenerative diseases and cerebral ischemia. We have provided evidence that PACAP is neuroprotective in several models of retinal degeneration in vivo. In our previous studies we showed that PACAP treatment significantly ameliorated the damaging effects of permanent bilateral common carotid artery occlusion (BCCAO). In the present study cell-type-specific markers were used in the same models in order to further specify the protective effects of PACAP. In rats BCCAO led to severe degeneration of all retinal layers that was attenuated by PACAP (100 pmol) administered unilaterally immediately following BCCAO into the vitreous body of one eye. Retinas were processed for immunohistochemistry after 3 weeks. Immunolabeling was executed for vesicular glutamate transporter 1 (VGLUT 1), vesicular gamma-aminobutyric acid transporter (VGAT), protein kinase Calpha (PKCalpha), glial fibrillary acidic protein (GFAP) and calcium-binding proteins, such as calbindin, calretinin, parvalbumin. In BCCAO retinas, intensity of immunopositivity for all antisera was dramatically decreased, except in the case of GFAP. In PACAP-treated retinas, immunostaining was similar to that of the control animals. In summary, our study presented immunohistochemical identification of cell types sensitive to chronic retinal hypoperfusion and the protective effects of PACAP. This analysis revealed that the retinoprotective effects of PACAP are not phenotype-specific, but it rather influences general cytoprotective pathways irrespective of the neuronal subtypes in the retina subjected to chronic hypoperfusion.
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Affiliation(s)
- Tamas Atlasz
- Department of Experimental Zoology and Neurobiology, University of Pecs, Pecs, Hungary.
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85
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Sanchez A, Tripathy D, Grammas P. RANTES release contributes to the protective action of PACAP38 against sodium nitroprusside in cortical neurons. Neuropeptides 2009; 43:315-20. [PMID: 19497618 PMCID: PMC2726654 DOI: 10.1016/j.npep.2009.05.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 05/12/2009] [Accepted: 05/13/2009] [Indexed: 12/21/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP), a promising neuroprotective peptide, plays an important role during development of the nervous system and in regeneration after injury. PACAP directly promotes survival via multiple signaling systems in neurons. This neuropeptide also has immuno-modulatory properties and can regulate the expression of various inflammatory mediators such as chemokines in nonneuronal cells. Chemokines and their G protein-coupled receptors are widely distributed in the brain, suggesting important functions for these inflammatory proteins in the CNS. The ability of brain endothelial cells and glia to release chemokines has been well documented, whether neurons are also a source for these mediators is unclear. The objective of this study is to determine whether PACAP38 affects expression of regulated on activation normal T expressed and secreted (RANTES) and macrophage inflammatory protein 1-alpha (MIP-1alpha) in cultured neurons and if these chemokines contribute to the neuroprotective effect of PACAP38. The data show that incubation of neuronal cultures with both PACAP38 and sodium nitroprusside (SNP) reduces the neuronal cell death evoked by SNP alone. PACAP38 dose-dependently increases immunodetectable levels of both RANTES and MIP-1alpha released in the media by cultured neurons. Co-treatment with a neutralizing antibody to RANTES decreases the PACAP38-mediated protection against SNP. Although RANTES treatment of neurons increased MIP-1alpha levels in the media and MIP-1alpha supports neuronal survival in unstressed cultures, MIP-1alpha does not protect neurons from SNP-induced toxicity. Furthermore, co-treatment with a MIP-1alpha neutralizing antibody did not affect PACAP38-induced protection against SNP. These results show that the protective effect of PACAP38 on cultured neurons is mediated, in part, by release of RANTES. The ability of PACAP to directly enhance neuronal survival through multiple intracellular signaling pathways as well as via the release of neuroprotective mediators such as RANTES highlights its utility as a potential therapeutic agent for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Alma Sanchez
- Garrison Institute on Aging, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Debjani Tripathy
- Garrison Institute on Aging, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Paula Grammas
- Garrison Institute on Aging, Texas Tech University Health Sciences Center, Lubbock, Texas
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86
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Riek-Burchardt M, Kolodziej A, Henrich-Noack P, Reymann KG, Höllt V, Stumm R. Differential regulation of CXCL12 and PACAP mRNA expression after focal and global ischemia. Neuropharmacology 2009; 58:199-207. [PMID: 19647005 DOI: 10.1016/j.neuropharm.2009.07.032] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 07/08/2009] [Accepted: 07/23/2009] [Indexed: 02/06/2023]
Abstract
Pituitary adenylate cyclase activating peptide (PACAP) and the chemokine stromal cell-derived factor (SDF-1) have been implicated in neuroprotection, neurogenesis, and regeneration. Focal ischemia is associated with rapid upregulation of PACAP in perifocal neurons and delayed induction of SDF-1 in hypoxic/ischemic tissues, the latter process being involved in the recruitment of stem cells and inflammatory cells. Here, we studied mRNA patterns of PACAP, SDF-1 and the cognate receptors PAC1 and CXCR4 by in situ hybridization in the rat hippocampus after transient global ischemia, a rat model for programmed death of CA1 pyramidal neurons. Cell death in CA1 was not associated with local induction of PACAP and SDF-1 expression or recruitment of CXCR4-expressing infiltrates. However, there was a transient, almost complete loss of SDF-1 expression in microvessels in all hippocampal regions. Granule cells transiently showed a decrease of SDF-1 and an increase of PACAP expression. While PAC1 mRNA was moderately decreased throughout the hippocampus, CXCR4 expression was selectively increased in the subgranular layer. We propose that altered PACAP and SDF-1 gene expression in granule cells plays a role in regulated neurogenesis after global ischemia. The finding that programmed neuronal death after global ischemia was not associated with SDF-1 upregulation or recruitment of CXCR4-expressing cells is in sharp contrast to SDF-1/CXCR4-mediated infiltration of infarct tissue after focal ischemia. Hence, the different modes of neuronal death after focal and global ischemia are associated with distinct SDF-1 and PACAP gene regulation patterns and distinct reorganization mechanisms.
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87
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Atlasz T, Szabadfi K, Reglődi D, Kiss P, Tamás A, Tóth G, Molnár A, Szabó K, Gábriel R. Effects of Pituitary Adenylate Cyclase Activating Polypeptide and Its Fragments on Retinal Degeneration Induced by Neonatal Monosodium Glutamate Treatment. Ann N Y Acad Sci 2009; 1163:348-52. [DOI: 10.1111/j.1749-6632.2008.03650.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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