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Dos Santos B, Piermartiri T, Tasca CI. The impact of purine nucleosides on neuroplasticity in the adult brain. Purinergic Signal 2024:10.1007/s11302-024-09988-9. [PMID: 38367178 DOI: 10.1007/s11302-024-09988-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 01/23/2024] [Indexed: 02/19/2024] Open
Abstract
Neuroplasticity refers to the nervous system's ability to adapt and reorganize its cell structures and neuronal networks in response to internal and external stimuli. In adults, this process involves neurogenesis, synaptogenesis, and synaptic and neurochemical plasticity. Several studies have reported the significant impact of the purinergic system on neuroplasticity modulation. And, there is considerable evidence supporting the role of purine nucleosides, such as adenosine, inosine, and guanosine, in this process. This review presents extensive research on how these nucleosides enhance the neuroplasticity of the adult central nervous system, particularly in response to damage. The mechanisms through which these nucleosides exert their effects involve complex interactions with various receptors and signaling pathways. Adenosine's influence on neurogenesis involves interactions with adenosine receptors, specifically A1R and A2AR. A1R activation appears to inhibit neuronal differentiation and promote astrogliogenesis, while A2AR activation supports neurogenesis, neuritogenesis, and synaptic plasticity. Inosine and guanosine positively impact cell proliferation, neurogenesis, and neuritogenesis. Inosine seems to modulate extracellular adenosine levels, and guanosine might act through interactions between purinergic and glutamatergic systems. Additionally, the review discusses the potential therapeutic implications of purinergic signaling in neurodegenerative and neuropsychiatric diseases, emphasizing the importance of these nucleosides in the neuroplasticity of brain function and recovery.
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Affiliation(s)
- Beatriz Dos Santos
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, 88040-900, Brazil
- Programa de Pós-Graduação Em Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Tetsade Piermartiri
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, 88040-900, Brazil.
- Programa de Pós-Graduação Em Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
| | - Carla I Tasca
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, 88040-900, Brazil.
- Programa de Pós-Graduação Em Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
- Programa de Pós-Graduação Em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
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Yun J, Park S, Park HY, Lee KA. Efficacy of Polydeoxyribonucleotide in Promoting the Healing of Diabetic Wounds in a Murine Model of Streptozotocin-Induced Diabetes: A Pilot Experiment. Int J Mol Sci 2023; 24:ijms24031932. [PMID: 36768255 PMCID: PMC9916466 DOI: 10.3390/ijms24031932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/11/2023] [Accepted: 01/12/2023] [Indexed: 01/20/2023] Open
Abstract
We assessed the efficacy of polydeoxyribonucleotide (PDRN) in accelerating the healing of diabetic wounds in a murine model of streptozotocin (STZ)-induced diabetes. After the creation of diabetic wounds, the mice of the PDRN SC, PDRN IP and PBS groups received a subcutaneous, an intra-peritoneal injection of PDRN and a subcutaneous injection of PBS, respectively. After euthanasia, time-dependent changes in the wound diameter and histologic scores were measured and vascular endothelial growth factor (VEGF), transforming growth factor-β1 (TGF-β1) and collagen types I and III were assessed for their expression levels. The PDRN SC and the PDRN IP groups showed a significantly smaller diameter of diabetic wounds, significantly higher histologic scores, a significantly greater expression of VEGF, a significantly lower expression of TGF-β1 and a significantly greater expression of collagen types I and III as compared with the PBS group (p < 0.05 or 0.0001). In conclusion, PDRN might be effective in promoting the healing of diabetic wounds in a murine model of STZ-induced diabetes.
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Affiliation(s)
- Jiyoung Yun
- Department of Plastic and Reconstructive Surgery, Inje University Busan Paik Hospital, College of Medicine, Inje University, Busan 47392, Republic of Korea
| | - SaeGwang Park
- Department of Microbiology and Immunology, College of Medicine, Inje University, Busan 47392, Republic of Korea
- Innovative Therapeutic Research Institute, Inje University Busan Paik Hospital, College of Medicine, Inje University, Busan 47392, Republic of Korea
| | - Ha Young Park
- Department of Pathology, Inje University Busan Paik Hospital, College of Medicine, Inje University, Busan 47392, Republic of Korea
| | - Kyung Ah Lee
- Department of Plastic and Reconstructive Surgery, Inje University Haeundae Paik Hospital, College of Medicine, Inje University, Busan 48108, Republic of Korea
- Correspondence:
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Polydeoxyribonucleotide: A Promising Biological Platform to Accelerate Impaired Skin Wound Healing. Pharmaceuticals (Basel) 2021; 14:ph14111103. [PMID: 34832885 PMCID: PMC8618295 DOI: 10.3390/ph14111103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/22/2021] [Accepted: 10/27/2021] [Indexed: 12/26/2022] Open
Abstract
The normal wound healing process is characterized by a complex, highly integrated cascade of events, requiring the interactions of many cell types, including inflammatory cells, fibroblasts, keratinocytes and endothelial cells, as well as the involvement of growth factors and enzymes. However, several diseases such as diabetes, thermal injury and ischemia could lead to an impaired wound healing process characterized by wound hypoxia, high levels of oxygen radicals, reduced angiogenesis, decreased collagen synthesis and organization. Polydeoxyribonucleotide (PDRN) has been used to improve wound healing through local and systemic administration thanks to its ability to promote cell migration and growth, angiogenesis, and to reduce inflammation on impaired wound healing models in vitro, in vivo and clinical studies. In light of all these observations, the aim of this review is to provide a full overview of PDRN applications on skin regeneration. We reviewed papers published in the last 25 years on PubMed, inserting “polydeoxyribonucleotide and wound healing” as the main search term. All data obtained proved the ability of PDRN in promoting physiological tissue repair through adenosine A2A receptor activation and salvage pathway suggesting that PDRN has proven encouraging results in terms of healing time, wound regeneration and absence of side effects.
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Chojnowski K, Opielka M, Nazar W, Kowianski P, Smolenski RT. Neuroprotective Effects of Guanosine in Ischemic Stroke-Small Steps towards Effective Therapy. Int J Mol Sci 2021; 22:6898. [PMID: 34199004 PMCID: PMC8268871 DOI: 10.3390/ijms22136898] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/22/2021] [Accepted: 06/23/2021] [Indexed: 12/12/2022] Open
Abstract
Guanosine (Guo) is a nucleotide metabolite that acts as a potent neuromodulator with neurotrophic and regenerative properties in neurological disorders. Under brain ischemia or trauma, Guo is released to the extracellular milieu and its concentration substantially raises. In vitro studies on brain tissue slices or cell lines subjected to ischemic conditions demonstrated that Guo counteracts destructive events that occur during ischemic conditions, e.g., glutaminergic excitotoxicity, reactive oxygen and nitrogen species production. Moreover, Guo mitigates neuroinflammation and regulates post-translational processing. Guo asserts its neuroprotective effects via interplay with adenosine receptors, potassium channels, and excitatory amino acid transporters. Subsequently, guanosine activates several prosurvival molecular pathways including PI3K/Akt (PI3K) and MEK/ERK. Due to systemic degradation, the half-life of exogenous Guo is relatively low, thus creating difficulty regarding adequate exogenous Guo distribution. Nevertheless, in vivo studies performed on ischemic stroke rodent models provide promising results presenting a sustained decrease in infarct volume, improved neurological outcome, decrease in proinflammatory events, and stimulation of neuroregeneration through the release of neurotrophic factors. In this comprehensive review, we discuss molecular signaling related to Guo protection against brain ischemia. We present recent advances, limitations, and prospects in exogenous guanosine therapy in the context of ischemic stroke.
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Affiliation(s)
- Karol Chojnowski
- Faculty of Medicine, Medical University of Gdańsk, Marii Skłodowskiej-Curie 3a, 80-210 Gdańsk, Poland; (K.C.); (W.N.)
| | - Mikolaj Opielka
- Department of Biochemistry, Medical University of Gdansk, 1 Debinki St., 80-211 Gdansk, Poland
- International Research Agenda 3P—Medicine Laboratory, Medical University of Gdańsk, 3A Sklodowskiej-Curie Street, 80-210 Gdansk, Poland
| | - Wojciech Nazar
- Faculty of Medicine, Medical University of Gdańsk, Marii Skłodowskiej-Curie 3a, 80-210 Gdańsk, Poland; (K.C.); (W.N.)
| | - Przemyslaw Kowianski
- Department of Anatomy and Neurobiology, Medical University of Gdansk, 1 Debinki Street, 80-211 Gdańsk, Poland;
- Institute of Health Sciences, Pomeranian University of Słupsk, Bohaterów Westerplatte 64, 76-200 Słupsk, Poland
| | - Ryszard T. Smolenski
- Department of Biochemistry, Medical University of Gdansk, 1 Debinki St., 80-211 Gdansk, Poland
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Mancinelli R, Fanò-Illic G, Pietrangelo T, Fulle S. Guanosine-Based Nucleotides, the Sons of a Lesser God in the Purinergic Signal Scenario of Excitable Tissues. Int J Mol Sci 2020; 21:ijms21051591. [PMID: 32111063 PMCID: PMC7084674 DOI: 10.3390/ijms21051591] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/20/2020] [Accepted: 02/25/2020] [Indexed: 12/28/2022] Open
Abstract
Purines are nitrogen compounds consisting mainly of a nitrogen base of adenine (ABP) or guanine (GBP) and their derivatives: nucleosides (nitrogen bases plus ribose) and nucleotides (nitrogen bases plus ribose and phosphate). These compounds are very common in nature, especially in a phosphorylated form. There is increasing evidence that purines are involved in the development of different organs such as the heart, skeletal muscle and brain. When brain development is complete, some purinergic mechanisms may be silenced, but may be reactivated in the adult brain/muscle, suggesting a role for purines in regeneration and self-repair. Thus, it is possible that guanosine-5′-triphosphate (GTP) also acts as regulator during the adult phase. However, regarding GBP, no specific receptor has been cloned for GTP or its metabolites, although specific binding sites with distinct GTP affinity characteristics have been found in both muscle and neural cell lines. Finally, even if the cross regulation mechanisms between the two different purines (ABP and GBP) are still largely unknown, it is now possible to hypothesize the existence of specific signal paths for guanosine-based nucleotides that are capable of modulating the intensity and duration of the intracellular signal, particularly in excitable tissues such as brain and muscle.
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Affiliation(s)
- Rosa Mancinelli
- Department of Neuroscience Imaging and Clinical Sciences, University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (R.M.); (T.P.)
- Interuniversity Institute of Miology (IIM), 66100 Chieti, Italy;
| | - Giorgio Fanò-Illic
- Interuniversity Institute of Miology (IIM), 66100 Chieti, Italy;
- Libera Università di Alcatraz, Santa Cristina di Gubbio, 06024 Gubbio, Italy
| | - Tiziana Pietrangelo
- Department of Neuroscience Imaging and Clinical Sciences, University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (R.M.); (T.P.)
- Interuniversity Institute of Miology (IIM), 66100 Chieti, Italy;
| | - Stefania Fulle
- Department of Neuroscience Imaging and Clinical Sciences, University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (R.M.); (T.P.)
- Interuniversity Institute of Miology (IIM), 66100 Chieti, Italy;
- Correspondence:
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Decker H, Piermartiri TCB, Nedel CB, Romão LF, Francisco SS, Dal-Cim T, Boeck CR, Moura-Neto V, Tasca CI. Guanosine and GMP increase the number of granular cerebellar neurons in culture: dependence on adenosine A 2A and ionotropic glutamate receptors. Purinergic Signal 2019; 15:439-450. [PMID: 31478180 DOI: 10.1007/s11302-019-09677-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 07/30/2019] [Indexed: 12/20/2022] Open
Abstract
The guanine-based purines (GBPs) have essential extracellular functions such as modulation of glutamatergic transmission and trophic effects on neurons and astrocytes. We previously showed that GBPs, such as guanosine-5'-monophosphate (GMP) or guanosine (GUO), promote the reorganization of extracellular matrix proteins in astrocytes, and increase the number of neurons in a neuron-astrocyte co-culture protocol. To delineate the molecular basis underlying these effects, we isolated cerebellar neurons in culture and treated them with a conditioned medium derived from astrocytes previously exposed to GUO or GMP (GBPs-ACM) or, directly, with GUO or GMP. Agreeing with the previous studies, there was an increase in the number of β-tubulin III-positive neurons in both conditions, compared with controls. Interestingly, the increase in the number of neurons in the neuronal cultures treated directly with GUO or GMP was more prominent, suggesting a direct interaction of GBPs on cerebellar neurons. To investigate this issue, we assessed the role of adenosine and glutamate receptors and related intracellular signaling pathways after GUO or GMP treatment. We found an involvement of A2A adenosine receptors, ionotropic glutamate N-methyl-D-aspartate (NMDA), and non-NMDA receptors in the increased number of cerebellar neurons. The signaling pathways extracellular-regulated kinase (ERK), calcium-calmodulin-dependent kinase-II (CaMKII), protein kinase C (PKC), phosphatidilinositol-3'-kinase (PI3-K), and protein kinase A (PKA) are also potentially involved with GMP and GUO effect. Such results suggest that GMP and GUO, and molecules released in GBPs-ACM promote the survival or maturation of primary cerebellar neurons or both via interaction with adenosine and glutamate receptors.
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Affiliation(s)
- Helena Decker
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, 88040-900, Florianópolis, SC, Brasil
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
| | - Tetsade C B Piermartiri
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, 88040-900, Florianópolis, SC, Brasil
| | - Cláudia B Nedel
- Departamento de Biologia Celular, Embriologia e Genética, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, 88040-900, Florianópolis, SC, Brasil
| | - Luciana F Romão
- Departamento de Anatomia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brasil
| | - Sheila S Francisco
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, 88040-900, Florianópolis, SC, Brasil
| | - Tharine Dal-Cim
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, 88040-900, Florianópolis, SC, Brasil
| | - Carina R Boeck
- Programa de Pós-graduação em Nanociências, Universidade Franciscana, Santa Maria, RS, Brasil
| | - Vivaldo Moura-Neto
- Departamento de Anatomia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brasil
- Instituto Estadual do Cérebro Paulo Niemeyer da Secretaria de Estado de Saúde do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
| | - Carla I Tasca
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, 88040-900, Florianópolis, SC, Brasil.
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Camargo A, Rodrigues ALS. Novel Targets for Fast Antidepressant Responses: Possible Role of Endogenous Neuromodulators. CHRONIC STRESS (THOUSAND OAKS, CALIF.) 2019; 3:2470547019858083. [PMID: 32440595 PMCID: PMC7219953 DOI: 10.1177/2470547019858083] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 05/28/2019] [Indexed: 12/13/2022]
Abstract
The available medications for the treatment of major depressive disorder have limitations, particularly their limited efficacy, delayed therapeutic effects, and the side effects associated with treatment. These issues highlight the need for better therapeutic agents that provide more efficacious and faster effects for the management of this disorder. Ketamine, an N-methyl-D-aspartate receptor antagonist, is the prototype for novel glutamate-based antidepressants that has been shown to cause a rapid and sustained antidepressant effect even in severe refractory depressive patients. Considering the importance of these findings, several studies have been conducted to elucidate the molecular targets for ketamine's effect. In addition, efforts are under way to characterize ketamine-like drugs. This review focuses particularly on evidence that endogenous glutamatergic neuromodulators may be able to modulate mood and to elicit fast antidepressant responses. Among these molecules, agmatine and creatine stand out as those with more published evidence of similarities with ketamine, but guanosine and ascorbic acid have also provided promising results. The possibility that these neuromodulators and ketamine have common neurobiological mechanisms, mainly the ability to activate mechanistic target of rapamycin and brain-derived neurotrophic factor signaling, and synthesis of synaptic proteins in the prefrontal cortex and/or hippocampus is presented and discussed.
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Affiliation(s)
- Anderson Camargo
- Neuroscience Postgraduate Program,
Center of Biological Sciences, Universidade Federal de Santa Catarina,
Florianópolis, Brazil
| | - Ana Lúcia S. Rodrigues
- Department of Biochemistry, Center of
Biological Sciences, Universidade Federal de Santa Catarina, Florianópolis,
Brazil
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Tasca CI, Lanznaster D, Oliveira KA, Fernández-Dueñas V, Ciruela F. Neuromodulatory Effects of Guanine-Based Purines in Health and Disease. Front Cell Neurosci 2018; 12:376. [PMID: 30459558 PMCID: PMC6232889 DOI: 10.3389/fncel.2018.00376] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 10/02/2018] [Indexed: 12/18/2022] Open
Abstract
The function of guanine-based purines (GBPs) is mostly attributed to the intracellular modulation of heteromeric and monomeric G proteins. However, extracellular effects of guanine derivatives have also been recognized. Thus, in the central nervous system (CNS), a guanine-based purinergic system that exerts neuromodulator effects, has been postulated. The thesis that GBPs are neuromodulators emerged from in vivo and in vitro studies, in which neurotrophic and neuroprotective effects of these kinds of molecules (i.e., guanosine) were demonstrated. GBPs induce several important biological effects in rodent models and have been shown to reduce seizures and pain, stabilize mood disorder behavior and protect against gliomas and diseases related with aging, such as ischemia or Parkinson and Alzheimer diseases. In vitro studies to evaluate the protective and trophic effects of guanosine, and of the nitrogenous base guanine, have been fundamental for understanding the mechanisms of action of GBPs, as well as the signaling pathways involved in their biological roles. Conversely, although selective binding sites for guanosine have been identified in the rat brain, GBP receptors have not been still described. In addition, GBP neuromodulation may depend on the capacity of GBPs to interact with well-known membrane proteins in glutamatergic and adenosinergic systems. Overall, in this review article, we present up-to-date GBP biology, focusing mainly on the mechanisms of action that may lead to the neuromodulator role of GBPs observed in neurological disorders.
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Affiliation(s)
- Carla I Tasca
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil.,Programa de Pós-Graduação em Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Débora Lanznaster
- Programa de Pós-Graduação em Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil.,UMR 1253, Team 2, INSERM/University of Tours, Tours, France
| | - Karen A Oliveira
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil.,Programa de Pós-Graduação em Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Victor Fernández-Dueñas
- Unitat de Farmacologia, Departament de Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Francisco Ciruela
- Unitat de Farmacologia, Departament de Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
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Lanznaster D, Dal-Cim T, Piermartiri TCB, Tasca CI. Guanosine: a Neuromodulator with Therapeutic Potential in Brain Disorders. Aging Dis 2016; 7:657-679. [PMID: 27699087 PMCID: PMC5036959 DOI: 10.14336/ad.2016.0208] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 02/08/2016] [Indexed: 12/20/2022] Open
Abstract
Guanosine is a purine nucleoside with important functions in cell metabolism and a protective role in response to degenerative diseases or injury. The past decade has seen major advances in identifying the modulatory role of extracellular action of guanosine in the central nervous system (CNS). Evidence from rodent and cell models show a number of neurotrophic and neuroprotective effects of guanosine preventing deleterious consequences of seizures, spinal cord injury, pain, mood disorders and aging-related diseases, such as ischemia, Parkinson’s and Alzheimer’s diseases. The present review describes the findings of in vivo and in vitro studies and offers an update of guanosine effects in the CNS. We address the protein targets for guanosine action and its interaction with glutamatergic and adenosinergic systems and with calcium-activated potassium channels. We also discuss the intracellular mechanisms modulated by guanosine preventing oxidative damage, mitochondrial dysfunction, inflammatory burden and modulation of glutamate transport. New and exciting avenues for future investigation into the protective effects of guanosine include characterization of a selective guanosine receptor. A better understanding of the neuromodulatory action of guanosine will allow the development of therapeutic approach to brain diseases.
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Affiliation(s)
- Débora Lanznaster
- 2Programa de Pós-graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina-UFSC, Campus Trindade, 88040-900, Florianópolis, SC, Brazil; 3CAPES Foundation, Ministry of Education of Brazil, Brasília - DF 70040-020, Brazil
| | - Tharine Dal-Cim
- 2Programa de Pós-graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina-UFSC, Campus Trindade, 88040-900, Florianópolis, SC, Brazil; 3CAPES Foundation, Ministry of Education of Brazil, Brasília - DF 70040-020, Brazil
| | - Tetsadê C B Piermartiri
- 2Programa de Pós-graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina-UFSC, Campus Trindade, 88040-900, Florianópolis, SC, Brazil; 3CAPES Foundation, Ministry of Education of Brazil, Brasília - DF 70040-020, Brazil
| | - Carla I Tasca
- 1Departamento de Bioquímica,; 2Programa de Pós-graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina-UFSC, Campus Trindade, 88040-900, Florianópolis, SC, Brazil
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10
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Bettio LEB, Gil-Mohapel J, Rodrigues ALS. Guanosine and its role in neuropathologies. Purinergic Signal 2016; 12:411-26. [PMID: 27002712 PMCID: PMC5023624 DOI: 10.1007/s11302-016-9509-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 03/08/2016] [Indexed: 02/08/2023] Open
Abstract
Guanosine is a purine nucleoside thought to have neuroprotective properties. It is released in the brain under physiological conditions and even more during pathological events, reducing neuroinflammation, oxidative stress, and excitotoxicity, as well as exerting trophic effects in neuronal and glial cells. In agreement, guanosine was shown to be protective in several in vitro and/or in vivo experimental models of central nervous system (CNS) diseases including ischemic stroke, Alzheimer's disease, Parkinson's disease, spinal cord injury, nociception, and depression. The mechanisms underlying the neurobiological properties of guanosine seem to involve the activation of several intracellular signaling pathways and a close interaction with the adenosinergic system, with a consequent stimulation of neuroprotective and regenerative processes in the CNS. Within this context, the present review will provide an overview of the current literature on the effects of guanosine in the CNS. The elucidation of the complex signaling events underlying the biochemical and cellular effects of this nucleoside may further establish guanosine as a potential therapeutic target for the treatment of several neuropathologies.
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Affiliation(s)
- Luis E B Bettio
- Department of Biochemistry, Center of Biological Sciences, Federal University of Santa Catarina, 88040-900, Florianópolis, SC, Brazil
- Division of Medical Sciences and UBC Island Medical Program, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Joana Gil-Mohapel
- Division of Medical Sciences and UBC Island Medical Program, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Ana Lúcia S Rodrigues
- Department of Biochemistry, Center of Biological Sciences, Federal University of Santa Catarina, 88040-900, Florianópolis, SC, Brazil.
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Di Liberto V, Mudò G, Garozzo R, Frinchi M, Fernandez-Dueñas V, Di Iorio P, Ciccarelli R, Caciagli F, Condorelli DF, Ciruela F, Belluardo N. The Guanine-Based Purinergic System: The Tale of An Orphan Neuromodulation. Front Pharmacol 2016; 7:158. [PMID: 27378923 PMCID: PMC4911385 DOI: 10.3389/fphar.2016.00158] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 05/30/2016] [Indexed: 11/17/2022] Open
Abstract
Guanine-based purines (GBPs) have been recently proposed to be not only metabolic agents but also extracellular signaling molecules that regulate important functions in the central nervous system. In such way, GBPs-mediated neuroprotection, behavioral responses and neuronal plasticity have been broadly described in the literature. However, while a number of these functions (i.e., GBPs neurothophic effects) have been well-established, the molecular mechanisms behind these GBPs-dependent effects are still unknown. Furthermore, no plasma membrane receptors for GBPs have been described so far, thus GBPs are still considered orphan neuromodulators. Interestingly, an intricate and controversial functional interplay between GBPs effects and adenosine receptors activity has been recently described, thus triggering the hypothesis that GBPs mechanism of action might somehow involve adenosine receptors. Here, we review recent data describing the GBPs role in the brain. We focus on the involvement of GBPs regulating neuronal plasticity, and on the new hypothesis based on putative GBPs receptors. Overall, we expect to shed some light on the GBPs world since although these molecules might represent excellent candidates for certain neurological diseases management, the lack of putative GBPs receptors precludes any high throughput screening intent for the search of effective GBPs-based drugs.
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Affiliation(s)
- Valentina Di Liberto
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo Palermo, Italy
| | - Giuseppa Mudò
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo Palermo, Italy
| | - Roberta Garozzo
- Department of Biomedical and Biotechnological Sciences, Unit of Medical Biochemistry, University of Catania Catania, Italy
| | - Monica Frinchi
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo Palermo, Italy
| | - Víctor Fernandez-Dueñas
- Department of Pathology and Experimental Therapeutics, Faculty of Medicine, Bellvitge Biomedical Research Institute, Institute of Neurosciences, University of Barcelona Barcelona, Spain
| | - Patrizia Di Iorio
- Department of Medical, Oral and Biotecnological Sciences, University of Chieti-Pescara Chieti, Italy
| | - Renata Ciccarelli
- Department of Medical, Oral and Biotecnological Sciences, University of Chieti-Pescara Chieti, Italy
| | - Francesco Caciagli
- Department of Medical, Oral and Biotecnological Sciences, University of Chieti-Pescara Chieti, Italy
| | - Daniele F Condorelli
- Department of Biomedical and Biotechnological Sciences, Unit of Medical Biochemistry, University of Catania Catania, Italy
| | - Francisco Ciruela
- Department of Pathology and Experimental Therapeutics, Faculty of Medicine, Bellvitge Biomedical Research Institute, Institute of Neurosciences, University of Barcelona Barcelona, Spain
| | - Natale Belluardo
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo Palermo, Italy
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Bettio LEB, Neis VB, Pazini FL, Brocardo PS, Patten AR, Gil-Mohapel J, Christie BR, Rodrigues ALS. The antidepressant-like effect of chronic guanosine treatment is associated with increased hippocampal neuronal differentiation. Eur J Neurosci 2016; 43:1006-15. [PMID: 26779605 DOI: 10.1111/ejn.13172] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 01/07/2016] [Indexed: 12/17/2022]
Abstract
Guanosine is a purine nucleoside that occurs naturally in the central nervous system, exerting trophic effects. Given its neuroprotective properties, the potential of guanosine as an antidepressant has been recently examined. Within this context, the present study sought to investigate the effects of chronic treatment with guanosine on the tail suspension test (TST), open field test and adult hippocampal neurogenesis. Swiss mice were administered guanosine for 21 days (5 mg/kg/day, p.o.) and subsequently submitted to the TST and open-field test. Following behavioural testing, animals were killed and the brains were processed for immunohistochemical analyses of hippocampal cell proliferation and neuronal differentiation. Animals treated with guanosine showed a reduction in immobility time in the TST without alterations in locomotor activity, confirming the antidepressant-like effect of this compound. Quantitative microscopic analysis did not reveal significant alterations in the numbers of Ki-67- and proliferating cell nuclear antigen (PCNA)-positive cells in the hippocampal dentate gyrus (DG) of guanosine-treated mice. However, guanosine treatment resulted in a significant increase in the number of immature neurons, as assessed by immunohistochemistry for the neurogenic differentiation protein. Interestingly, this effect was localized to the ventral hippocampal DG, a functionally distinct region of this structure known to regulate emotional and motivational behaviours. Taken together, our results suggest that the antidepressant-like effect of chronic guanosine treatment is associated with an increase in neuronal differentiation, reinforcing the notion that this nucleoside may be an endogenous mood modulator.
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Affiliation(s)
- Luis E B Bettio
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, 88040-900, Florianópolis-SC, Brazil.,Division of Medical Sciences and UBC Island Medical Program, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Vivian B Neis
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, 88040-900, Florianópolis-SC, Brazil
| | - Francis L Pazini
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, 88040-900, Florianópolis-SC, Brazil
| | - Patricia S Brocardo
- Department of Morphological Sciences, Center of Biological Sciences, Universidade Federal de Santa Catarina, 88040-900, Florianópolis-SC, Brazil
| | - Anna R Patten
- Division of Medical Sciences and UBC Island Medical Program, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Joana Gil-Mohapel
- Division of Medical Sciences and UBC Island Medical Program, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Brian R Christie
- Division of Medical Sciences and UBC Island Medical Program, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Ana Lúcia S Rodrigues
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, 88040-900, Florianópolis-SC, Brazil
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13
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Purine nucleosides in neuroregeneration and neuroprotection. Neuropharmacology 2015; 104:226-42. [PMID: 26577017 DOI: 10.1016/j.neuropharm.2015.11.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 11/05/2015] [Accepted: 11/06/2015] [Indexed: 12/20/2022]
Abstract
In the present review, we stress the importance of the purine nucleosides, adenosine and guanosine, in protecting the nervous system, both centrally and peripherally, via activation of their receptors and intracellular signalling mechanisms. A most novel part of the review focus on the mechanisms of neuronal regeneration that are targeted by nucleosides, including a recently identified action of adenosine on axonal growth and microtubule dynamics. Discussion on the role of the purine nucleosides transversally with the most established neurotrophic factors, e.g. brain derived neurotrophic factor (BDNF), glial derived neurotrophic factor (GDNF), is also focused considering the intimate relationship between some adenosine receptors, as is the case of the A2A receptors, and receptors for neurotrophins. This article is part of the Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'.
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Ebrahimi F, Koch M, Pieroh P, Ghadban C, Hobusch C, Bechmann I, Dehghani F. Time dependent neuroprotection of mycophenolate mofetil: effects on temporal dynamics in glial proliferation, apoptosis, and scar formation. J Neuroinflammation 2012; 9:89. [PMID: 22569136 PMCID: PMC3430572 DOI: 10.1186/1742-2094-9-89] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 05/08/2012] [Indexed: 12/14/2022] Open
Abstract
Background Immunosuppressants such as mycophenolate mofetil (MMF) have the capacity to inhibit microglial and astrocytic activation and to reduce the extent of cell death after neuronal injury. This study was designed to determine the effective neuroprotective time frame in which MMF elicits its beneficial effects, by analyzing glial cell proliferation, migration, and apoptosis. Methods Using organotypic hippocampal slice cultures (OHSCs), temporal dynamics of proliferation and apoptosis after N-methyl-D-aspartate (NMDA)-mediated excitotoxicity were analyzed by quantitative morphometry of Ki-67 or cleaved caspase-3 immunoreactive glial cells. Treatment on NMDA-lesioned OHSCs with mycophenolate mofetil (MMF)100 μg/mL was started at different time points after injury or performed within specific time frames, and the numbers of propidium iodide (PI)+ degenerating neurons and isolectin (I)B4+ microglial cells were determined. Pre-treatment with guanosine 100 μmol/l was performed to counteract MMF-induced effects. The effects of MMF on reactive astrocytic scar formation were investigated in the scratch-wound model of astrocyte monolayers. Results Excitotoxic lesion induction led to significant increases in glial proliferation rates between 12 and 36 hours after injury and to increased levels of apoptotic cells between 24 and 72 hours after injury. MMF treatment significantly reduced glial proliferation rates without affecting apoptosis. Continuous MMF treatment potently reduced the extent of neuronal cell demise when started within the first 12 hours after injury. A crucial time-frame of significant neuroprotection was identified between 12 and 36 hours after injury. Pre-treatment with the neuroprotective nucleoside guanosine reversed MMF-induced antiproliferative effects on glial cells. In the scratch-wound model, gap closure was reached within 48 hours in controls, and was potently inhibited by MMF. Conclusions Our data indicate that immunosuppression by MMF significantly attenuates the extent of neuronal cell death when administered within a crucial time frame after injury. Moreover, long-lasting immunosuppression, as required after solid-organ transplantation, does not seem to be necessary. Targeting inosine 5-monophosphate dehydrogenase, the rate-limiting enzyme of purine synthesis, is an effective strategy to modulate the temporal dynamics of proliferation and migration of microglia and astrocytes, and thus to reduce the extent of secondary neuronal damage and scar formation.
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Affiliation(s)
- Fahim Ebrahimi
- Institute of Anatomy, Leipzig University, Leipzig, Germany
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15
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Effects of chronic guanosine treatment on hippocampal damage and cognitive impairment of rats submitted to chronic cerebral hypoperfusion. Neurol Sci 2011; 33:985-97. [PMID: 22167652 DOI: 10.1007/s10072-011-0872-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 11/23/2011] [Indexed: 01/22/2023]
Abstract
Chronic cerebral hypoperfusion contributes to a cognitive decline related to brain disorders. Its experimental model in rats is a permanent bilateral common carotid artery occlusion (2VO). Overstimulation of the glutamatergic system excitotoxicity due to brain energetic disturbance in 2VO animals seems to play a pivotal role as a mechanism of cerebral damage. The nucleoside guanosine (GUO) exerts extracellular effects including antagonism of glutamatergic activity. Accordingly, our group demonstrated several neuroprotective effects of GUO against glutamatergic excitotoxicity. Therefore, in this study, we evaluated a chronic GUO treatment effects in rats submitted to 2VO. We evaluated the animals performance in the Morris water maze and hippocampal damage by neurons and astrocytes immunohistochemistry. In addition, we investigated the cerebrospinal fluid (CSF) brain derived neurotrophic factor (BDNF) and serum S100B levels. Additionally, the purine CSF and plasma levels were determined. GUO treatment did not prevent the cognitive impairment promoted by 2VO. However, none of the 2VO animals treated with GUO showed differences in the hippocampal regions compared to control, while 20% of 2VO rats not treated with GUO presented loss of pyramidal neurons and increased glial labeling cells in CA1 hippocampal region. In addition, we did not observe differences in CSF BDNF nor serum S100B levels among the groups. Of note, both the 2VO surgery and GUO treatment changed the purine CSF and plasma profile. In conclusion, GUO treatment did not prevent the cognitive impairment observed in 2VO animals, but our data suggest that GUO could be neuroprotective against hippocampal damage induced by 2VO.
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16
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Garozzo R, Sortino MA, Vancheri C, Condorelli DF. Antiproliferative effects induced by guanine-based purines require hypoxanthine-guanine phosphoribosyltransferase activity. Biol Chem 2011; 391:1079-89. [PMID: 20536392 DOI: 10.1515/bc.2010.106] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Guanine (GUA), guanosine and GMP exert a marked growth inhibition on the U87 glioma cell line that is not seen with other tested nucleotides, nucleosides and nucleobases. This effect could be replicated in several different human tumoral cell lines. Guanine shows a higher potency than guanosine or GMP, and co-treatments with adenosine or adenine are able to antagonize or revert the antiproliferative effect of guanine. The loss of the guanine effect in a cell line bearing a mutated inactive hypoxanthine-guanine phosphoribosyltransferase (HGPRT), and the decreased potency of GUA in U87 cells silenced for HGPRT transcripts, demonstrates the central role of the intracellular metabolism of GUA for growth-inhibitory effects. Considering the potential application of growth-inhibitory substances in anticancer therapy, knowledge of the molecular mechanism underlying GUA-induced effects encourages studies aimed at defining possible tumoral targets for experimental therapies.
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Affiliation(s)
- Roberta Garozzo
- Department of Chemical Sciences, Section of Biochemistry, University of Catania, I-95125 Catania, Italy
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17
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Volpini R, Marucci G, Buccioni M, Dal Ben D, Lambertucci C, Lammi C, Mishra RC, Thomas A, Cristalli G. Evidence for the existence of a specific g protein-coupled receptor activated by guanosine. ChemMedChem 2011; 6:1074-80. [PMID: 21500353 DOI: 10.1002/cmdc.201100100] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 03/11/2011] [Indexed: 11/10/2022]
Abstract
Guanosine, released extracellularly from neurons and glial cells, plays important roles in the central nervous system, including neuroprotection. The innovative DELFIA Eu-GTP binding assay was optimized for characterization of the putative guanosine receptor binding site at rat brain membranes by using a series of novel and known guanosine derivatives. These nucleosides were prepared by modifying the purine and sugar moieties of guanosine at the 6- and 5'-positions, respectively. Results of these experiments prove that guanosine, 6-thioguanosine, and their derivatives activate a G protein-coupled receptor that is different from the well-characterized adenosine receptors.
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Affiliation(s)
- Rosaria Volpini
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino via S. Agostino 1, 62032 Camerino, Italy
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18
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Dehghani F, Sayan M, Conrad A, Evers J, Ghadban C, Blaheta R, Korf HW, Hailer NP. Inhibition of microglial and astrocytic inflammatory responses by the immunosuppressant mycophenolate mofetil. Neuropathol Appl Neurobiol 2011; 36:598-611. [PMID: 20609108 DOI: 10.1111/j.1365-2990.2010.01104.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AIMS Nucleotide depletion induced by the immunosuppressant mycophenolate mofetil (MMF) has been shown to exert neuroprotective effects. It remains unclear whether nucleotide depletion directly counteracts neuronal demise or whether it inhibits microglial or astrocytic activation, thereby resulting in indirect neuroprotection. METHODS Effects of MMF on isolated microglial cells, astrocyte/microglial cell co-cultures and isolated hippocampal neurones were analysed by immunocytochemistry, quantitative morphometry, and elisa. RESULTS We found that: (i) MMF suppressed lipopolysaccharide-induced microglial secretion of interleukin-1β, tumour necrosis factor-α and nitric oxide; (ii) MMF suppressed lipopolysaccharide-induced astrocytic production of tumour necrosis factor-α but not of nitric oxide; (iii) MMF strongly inhibited proliferation of both microglial cells and astrocytes; (iv) MMF did not protect isolated hippocampal neurones from excitotoxic injury; and (v) effects of MMF on glial cells were reversed after treatment with guanosine. CONCLUSIONS Nucleotide depletion induced by MMF inhibits microglial and astrocytic activation. Microglial and astrocytic proliferation is suppressed by MMF-induced inhibition of the salvage pathway enzyme inosine monophosphate dehydrogenase. The previously observed neuroprotection after MMF treatment seems to be indirectly mediated, making this compound an interesting immunosuppressant in the treatment of acute central nervous system lesions.
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Affiliation(s)
- F Dehghani
- Dr. Senckenbergische Anatomie, Institute of Anatomy 2, Goethe-University, Frankfurt am Main, Germany.
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19
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Guarnieri S, Pilla R, Morabito C, Sacchetti S, Mancinelli R, Fanò G, Mariggiò MA. Extracellular guanosine and GTP promote expression of differentiation markers and induce S-phase cell-cycle arrest in human SH-SY5Y neuroblastoma cells. Int J Dev Neurosci 2008; 27:135-47. [PMID: 19111604 DOI: 10.1016/j.ijdevneu.2008.11.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2008] [Revised: 11/04/2008] [Accepted: 11/29/2008] [Indexed: 01/09/2023] Open
Abstract
SH-SY5Y neuroblastoma cells, a model for studying neuronal differentiation, are able to differentiate into either cholinergic or dopaminergic/adrenergic phenotypes depending on media conditions. Using this system, we asked whether guanosine (Guo) or guanosine-5'-triphosphate (GTP) are able to drive differentiation towards one particular phenotype. Differentiation was determined by evaluating the frequency of cells bearing neurites and assessing neurite length after exposure to different concentrations of Guo or GTP for different durations. After 6 days, 0.3 mM Guo or GTP induced a significant increase in the number of cells bearing neurites and increased neurite length. Western blot analyses confirmed that purines induced differentiation; cells exposed to purines showed increases in the levels of GAP43, MAP2, and tyrosine hydroxylase. Proliferation assays and cytofluorimetric analyses indicated a significant anti-proliferative effect of purines, and a concentration-dependent accumulation of cells in S-phase, starting after 24 h of purine exposure and extending for up to 6 days. A transcriptional profile analysis using gene arrays showed that an up-regulation of cyclin E2/cdk2 evident after 24 h was responsible for S-phase entry, and a concurrent down-regulation of cell-cycle progression-promoting cyclin B1/B2 prevented S-phase exit. In addition, patch-clamp recordings revealed that 0.3 mM Guo or GTP, after 6 day incubation, significantly decreased Na(+) currents. In conclusion, we showed Guo- and GTP-induced cell-cycle arrest in neuroblastoma cells and suggest that this makes these cells more responsive to differentiation processes that favor the dopaminergic/adrenergic phenotype.
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Affiliation(s)
- S Guarnieri
- Dipartamento Scienze Mediche di Base ed Applicate Università G. d'Annunzio, Chieti, Italy
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Rathbone M, Pilutti L, Caciagli F, Jiang S. Neurotrophic effects of extracellular guanosine. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2008; 27:666-72. [PMID: 18600524 DOI: 10.1080/15257770802143913] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Central nervous system (CNS) astrocytes release guanosine extracellularly, that exerts trophic effects. In CNS, extracellular guanosine (GUO) stimulates mitosis, synthesis of trophic factors, and cell differentiation, including neuritogenesis, is neuroprotective, and reduces apoptosis due to several stimuli. Specific receptor-like binding sites for eGUO in the nervous system may mediate its effects through both MAP kinase and PI3-kinase signalling pathways. Extracellular guanine (eGUA) also exerts several effects; the trophic effects of eGUO are likely regulated by conversion of eGUO to eGUA by a membrane located purine nucleoside phosphorylase (ecto-PNP) and by conversion of eGUA to xanthine by guanine deaminase.
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Affiliation(s)
- Michel Rathbone
- Department of Medicine-Neurology, McMaster University, Hamilton, Canada.
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21
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Williams M, Jacobson KA. P 2-Purinoceptors: Advances and therapeutic opportunities. Expert Opin Investig Drugs 2008; 4:925-934. [PMID: 31827369 DOI: 10.1517/13543784.4.10.925] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The recent cloning of a number of distinct receptors belonging to the P2-purinoceptor superfamily has provided conclusive evidence for a pivotal role for ATP and other nucleotides as effector molecules involved in cell-to-cell communication and the modulation of many basic aspects of tissue function. ATP itself is being clinically evaluated as a cytotoxic agent for the treatment of cancer and as an adjunct to inhalation anaesthetic use. The pyrimidine nucleotide, UTP, is in clinical trials for the treatment of cystic fibrosis. The stable ATP bioisostere, ARL 67085, is being developed as a novel antithrombotic agent, blocking with a superior safety profile and increased efficacy as compared to other agents. The diversity of P2 receptors, with eleven having been defined using both pharmacological and molecular cloning criteria, indicates considerable additional potential and subtlety in regard to the effects of ATP on tissue function and pathophysiology.
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Affiliation(s)
- Michael Williams
- Neuroscience Discovery, Pharmaceutical Products Division, Abbott Laboratories, Abbott Park, IL 60064, USA
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
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22
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Chang R, Algird A, Bau C, Rathbone MP, Jiang S. Neuroprotective effects of guanosine on stroke models in vitro and in vivo. Neurosci Lett 2008; 431:101-5. [PMID: 18191898 DOI: 10.1016/j.neulet.2007.11.072] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Revised: 11/02/2007] [Accepted: 11/09/2007] [Indexed: 01/18/2023]
Abstract
Deprivation of oxygen and glucose for 5h induces apoptosis in SH-SY5Y neuroblastoma cell cultures. After combined glucose and oxygen deprivation (CGOD) addition of guanosine (100 microM), a non-adenine-based purine nucleoside, significantly reduced the proportion of cells undergoing apoptosis. To determine whether guanosine was also neuroprotective in vivo, we undertook middle cerebral artery occlusion (MCAo) on male Wistar rats and administered guanosine (8mg/kg), intraperitoneally, or saline (vehicle control) daily for 7 days. Guanosine prolonged rat survival and decreased both neurological deficits and tissue damage resulting from MCAo. These data are the first to demonstrate that guanosine protects neurons from the effects of CGOD even when administered 5h after the stimulus, and is neuroprotective in experimental stroke in rats.
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Affiliation(s)
- Ruby Chang
- Department of Neurosurgery, McMaster University, Health Sciences Centre, 4N71B, 1200 Main Street West, Hamilton, ON L8N 3Z5, Canada
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23
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Nagasawa K, Kawasaki F, Tanaka A, Nagai K, Fujimoto S. Characterization of guanine and guanosine transport in primary cultured rat cortical astrocytes and neurons. Glia 2007; 55:1397-404. [PMID: 17674371 DOI: 10.1002/glia.20550] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In this study, we examined the transport mechanisms for guanine and guanosine in rat neurons and astrocytes, and compared their characteristics. In the both types of cell, the uptake of [(3)H]guanine and [(3)H]guanosine was time-, temperature-, and concentration-dependent, and Na(+)-independent. Their uptake decreased on the addition of purine and pyrimidine nucleobases or nucleosides, and the inhibitory effect of the purine analogues was greater than that of the pyrimidine ones. In both cell types, equilibrative nucleoside transporter (ENT) 1 and ENT2 expression was confirmed at the mRNA level, and nitrobenzylmercaptopurine riboside, a representative inhibitor for ENT, decreased their uptake at concentrations of over 10 microM. Comparing uptake characteristics between the substrates, [(3)H]guanine uptake exhibited higher affinity and clearance than [(3)H]guanosine uptake in each type of cell. Although between neurons and astrocytes, there was no difference in the apparent uptake clearance for [(3)H]guanine and [(3)H]guanosine, which was calculated based upon the cellular protein content, the cellular uptake clearance was significantly greater in astrocytes than in neurons. These findings indicate that guanine and guanosine, of which the former is a preferable substrate, are taken up into both neurons and astrocytes via ENT2, and that the extracellular concentrations of guanine and guanosine are mainly regulated by astrocytes to maintain brain physiology.
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Affiliation(s)
- Kazuki Nagasawa
- Department of Environmental Biochemistry, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto, Japan.
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24
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Early temporal changes in ecto-nucleotidase activity after cortical stab injury in rat. Neurochem Res 2007; 33:873-9. [PMID: 17992570 DOI: 10.1007/s11064-007-9529-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Accepted: 10/11/2007] [Indexed: 01/19/2023]
Abstract
During a variety of insults to the brain adenine nucleotides are released in large quantities from damaged cells, triggering multiple cellular responses to injury. Here, we evaluated changes in extracellular ATP, ADP and AMP hydrolysis at different times (0-24 hours) after unilateral cortical stab injury (CSI) in adult rats. Results demonstrated that 24 hours following CSI, ATP and ADP hydrolyzing activities were not significantly altered in injured cortex. Based on calculated V (ATP)/V (ADP) ratio it was concluded that ATP/ADP hydrolysis was primarily catalyzed by NTPDase1 enzyme form. In contrast, AMP hydrolysis, catalyzed by 5'-nucleotidase, was significantly reduced at least 4 hours following CSI. Kinetic analysis and Lineweaver-Burk transformation of the enzyme velocities obtained over the range of AMP concentrations (0.05-1.50 mM) revealed that inhibition of 5'-nucleotidase activity after CSI was of the uncompetitive type. Taken together our data suggest that injured tissue has reduced potential for extracellular metabolism of adenine nucleotides in early stages after CSI.
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25
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Schmidt AP, Lara DR, Souza DO. Proposal of a guanine-based purinergic system in the mammalian central nervous system. Pharmacol Ther 2007; 116:401-16. [PMID: 17884172 DOI: 10.1016/j.pharmthera.2007.07.004] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Accepted: 07/30/2007] [Indexed: 01/06/2023]
Abstract
Guanine-based purines have been traditionally studied as modulators of intracellular processes, mainly G-protein activity. However, they also exert several extracellular effects not related to G proteins, including modulation of glutamatergic activity, trophic effects on neural cells, and behavioral effects. In this article, the putative roles of guanine-based purines on the nervous system are reviewed, and we propose a specific guanine-based purinergic system in addition to the well-characterized adenine-based purinergic system. Current evidence suggest that guanine-based purines modulate glutamatergic parameters, such as glutamate uptake by astrocytes and synaptic vesicles, seizures induced by glutamatergic agents, response to ischemia and excitotoxicity, and are able to affect learning, memory and anxiety. Additionally, guanine-based purines have important trophic functions affecting the development, structure, or maintenance of neural cells. Although studies addressing the mechanism of action (receptors and second messenger systems) of guanine-based purines are still insufficient, these findings point to the guanine-based purines (nucleotides and guanosine) as potential new targets for neuroprotection and neuromodulation.
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Affiliation(s)
- André P Schmidt
- Departamento de Bioquímica, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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26
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Oleskovicz SPB, Martins WC, Leal RB, Tasca CI. Mechanism of guanosine-induced neuroprotection in rat hippocampal slices submitted to oxygen-glucose deprivation. Neurochem Int 2007; 52:411-8. [PMID: 17822807 DOI: 10.1016/j.neuint.2007.07.017] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Revised: 07/17/2007] [Accepted: 07/25/2007] [Indexed: 12/23/2022]
Abstract
Guanine derivates have been implicated in many relevant extracellular roles, such as modulation of glutamate transmission, protecting neurons against excitotoxic damage. Guanine derivatives are spontaneously released to the extracellular space from cultured astrocytes during oxygen-glucose deprivation (OGD) and may act as trophic factors, glutamate receptors blockers or glutamate transport modulators, thus promoting neuroprotection. The aim of this study was to evaluate the mechanisms involved in the neuroprotective role of the nucleoside guanosine in rat hippocampal slices submitted to OGD, identifying a putative extracellular binding site and the intracellular signaling pathways related to guanosine-induced neuroprotection. Cell damage to hippocampal slices submitted to 15 min of OGD followed by 2 h of reperfusion was decreased by the addition of guanosine (100 microM) or guanosine-5'-monophosphate (GMP, 100 microM). The neuroprotective effect of guanosine was not altered by the addition of adenosine receptor antagonists, nucleosides transport inhibitor, glutamate receptor antagonists, glutamate transport inhibitors, and a non-selective Na(+) and Ca(2+) channel blocker. However, in a Ca(2+)-free medium (by adding EGTA), guanosine was ineffective. Nifedipine (a Ca(2+) channel blocker) increased the neuroprotective effect of guanosine and 4-aminopyridine, a K(+) channel blocker, reversed the neuroprotective effect of guanosine. Evaluation of the intracellular signaling pathways associated with guanosine-induced neuroprotection showed the involvement of PKA, PKC, MEK and PI-3 K pathways, but not CaMKII. Therefore, this study shows guanosine is acting via K(+) channels activation, depending on extracellular Ca(2+) levels and via modulation of the PKA, PKC, MEK and/or PI-3 K pathways.
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Affiliation(s)
- Scheyla P B Oleskovicz
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, 88040-900 Florianópolis, SC, Brazil
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Guizzardi S, Martini D, Bacchelli B, Valdatta L, Thione A, Scamoni S, Uggeri J, Ruggeri A. Effects of heat deproteinate bone and polynucleotides on bone regeneration: an experimental study on rat. Micron 2007; 38:722-8. [PMID: 17587587 DOI: 10.1016/j.micron.2007.05.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Revised: 05/09/2007] [Accepted: 05/10/2007] [Indexed: 11/19/2022]
Abstract
This experimental study evaluated the effects of polynucleotides on bone regeneration on rats. Defects with a diameter of 2mm were prepared in the thickness of cortical bone of 32 rat tibiae and filled with different compounds: polynucleotide gel (PDRN), deproteinated porcine cortical bone (HDB) obtained by high temperature heating in the form of granules and a paste made of HDB granules and PDRN gel. Bone regeneration of the gaps was histologically analysed after a treatment time ranging from 1 to 12 weeks. Both PDRN and HDB stimulated bone growth and repair, but the paste prepared combining HDB granules and PDRN showed the best performance with faster filling, better osteconductive and biocompatible properties and easier handling. This study suggests that the paste prepared combining HDB and PDRN gel induces rapid bone regeneration in different clinical situations.
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Affiliation(s)
- S Guizzardi
- Department of Experimental Medicine, Section of Histology, University of Parma, Italy.
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Ballerini P, Di Iorio P, Caciagli F, Rathbone MP, Jiang S, Nargi E, Buccella S, Giuliani P, D'Alimonte I, Fischione G, Masciulli A, Romano S, Ciccarelli R. P2Y2 receptor up-regulation induced by guanosine or UTP in rat brain cultured astrocytes. Int J Immunopathol Pharmacol 2006; 19:293-308. [PMID: 16831297 DOI: 10.1177/039463200601900207] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Among P2 metabotropic ATP receptors, P2Y2 subtype seems to be peculiar as its upregulation triggers important biological events in different cells types. In non-stimulated cells including astrocytes, P2Y2 receptors are usually expressed at levels lower than P2Y1 sites, however the promoter region of the P2Y2 receptors has not yet been studied and little is known about the mechanisms underlying the regulation of the expression of this ATP receptor. We showed that not only UTP and ATP are the most potent and naturally occurring agonist for P2Y2 sites, but also guanosine induced an up-regulation of astrocyte P2Y2 receptor mRNA evaluated by Northern blot analysis. We also focused our attention on this nucleoside since in our previous studies it was reported to be released by cultured astrocytes and to exert different neuroprotective effects. UTP and guanosine-evoked P2Y2 receptor up-regulation in rat brain cultured astrocytes was linked to an increased P2Y2-mediated intracellular calcium response, thus suggesting an increased P2Y2 activity. Actinomycin D, a RNA polymerase inhibitor, abrogated both UTP and guanosine-mediated P2Y2 up-regulation, thus indicating that de novo transcription was required. The effect of UTP and guanosine was also evaluated in astrocytes pretreated with different inhibitors of signal transduction pathways including ERK, PKC and PKA reported to be involved in the regulation of other cell surface receptor mRNAs. The results show that ERK1-2/MAPK pathway play a key role in the P2Y2 receptor up-regulation mediated by either UTP or guanosine. Moreover, our data suggest that PKA is also involved in guanosine-induced transcriptional activation of P2Y2 mRNA and that increased intracellular calcium levels and PKC activation may also mediate P2Y2 receptor up-regulation triggered by UTP. The extracellular release of ATP under physiological and pathological conditions has been widely studied. On the contrary, little is known about the release of pyrimidines and in particular of UTP. Here we show that astrocytes are able to release UTP, either at rest or during and following hypoxia/hypoglycemia obtained by submitting the cells to glucose-oxygen deprivation (OGD). Interestingly, also P2Y2 receptor mRNA increased by about two-fold the control values when the cultures were submitted to OGD. It has been recently reported that P2Y2 receptors can play a protective role in astrocytes, thus either guanosine administration or increased extracellular concentrations of guanosine and UTP reached locally following CNS injury may increase P2Y2-mediated biological events aimed at promoting a protective astrocyte response.
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Affiliation(s)
- P Ballerini
- Dept. of Biomedical Sciences, Section of Pharmacology and Toxicology, Medical School, University G. D'Annunzio of Chieti-Pescara, Via dei Vestini 29, 66013 Chieti, Italy.
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29
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Benfenati V, Caprini M, Nobile M, Rapisarda C, Ferroni S. Guanosine promotes the up-regulation of inward rectifier potassium current mediated by Kir4.1 in cultured rat cortical astrocytes. J Neurochem 2006; 98:430-45. [PMID: 16805837 DOI: 10.1111/j.1471-4159.2006.03877.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Guanosine (Guo) is an endogenous neuroprotective molecule of the CNS, which has various acute and long-term effects on both neurones and astroglial cells. Whether Guo also modulates the activity/expression of ion channels involved in homeostatic control of extracellular potassium by the astrocytic syncytium is still unknown. Here we provide electrophysiological evidence that chronic exposure (48 h) to Guo (500 microm) promotes the functional expression of an inward rectifier K+ (Kir) conductance in primary cultured rat cortical astrocytes. Molecular screening indicated that Guo promotes the up-regulation of the Kir4.1 channel, the major component of the Kir current in astroglia in vivo. Furthermore, the properties of astrocytic Kir current overlapped those of the recombinant Kir4.1 channel expressed in a heterologous system, strongly suggesting that the Guo-induced Kir conductance is mainly gated by Kir4.1. In contrast, the expression levels of two other Kir channel proteins were either unchanged (Kir2.1) or decreased (Kir5.1). Finally, we showed that inhibition of translational process, but not depression of transcription, prevents the Guo-induced up-regulation of Kir4.1, indicating that this nucleoside acts through de novo protein synthesis. Because accumulating data indicate that down-regulation of astroglial Kir current contributes to the pathogenesis of neurodegenerative diseases associated with dysregulation of extracellular K+ homeostasis, these results support the notion that Guo might be a molecule of therapeutic interest for counteracting the detrimental effect of K+-buffering impairment of the astroglial syncytium that occurs in pathological conditions.
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Affiliation(s)
- Valentina Benfenati
- Department of Human and General Physiology, University of Bologna, Bologna, Italy
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Jiang S, Zavitz CCJ, Wang J, Saraf A, Zielinski R, Ramsbottom JD, Ballerini P, D'Alimonte I, Romano S, Fischione G, Traversa U, Werstiuk ES, Rathbone MP. Non-adenine based purines accelerate wound healing. Purinergic Signal 2006; 2:651-61. [PMID: 18404468 PMCID: PMC2096660 DOI: 10.1007/s11302-006-9022-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Revised: 05/22/2006] [Accepted: 05/29/2006] [Indexed: 01/26/2023] Open
Abstract
Wound healing is a complex sequence of cellular and molecular processes that involves multiple cell types and biochemical mediators. Several growth factors have been identified that regulate tissue repair, including the neurotrophin nerve growth factor (NGF). As non-adenine based purines (NABPs) are known to promote cell proliferation and the release of growth factors, we investigated whether NABPs had an effect on wound healing. Full-thickness, excisional wound healing in healthy BALB/c mice was significantly accelerated by daily topical application of NABPs such as guanosine (50% closure by days 2.5′.8). Co-treatment of wounds with guanosine plus anti-NGF reversed the guanosine-promoted acceleration of wound healing, indicating that this effect of guanosine is mediated, at least in part, by NGF. Selective inhibitors of the NGF-inducible serine/threonine protein kinase (protein kinase N), such as 6-methylmercaptopurine riboside abolished the acceleration of wound healing caused by guanosine, confirming that activation of this enzyme is required for this effect of guanosine. Treatment of genetically diabetic BKS.Cg-m+/+lepr db mice, which display impaired wound healing, with guanosine led to accelerated healing of skin wounds (25% closure by days 2.8′.0). These results provide further confirmation that the NABP-mediated acceleration of cutaneous wound healing is mediated via an NGF-dependent mechanism. Thus, NABPs may offer an alternative and viable approach for the treatment of wounds in a clinical setting.
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Affiliation(s)
- Shucui Jiang
- Department of Surgery, McMaster University Health Sciences Centre, 4N71B, 1200 Main Street West, Hamilton, Ontario, L8N 3Z5, Canada,
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31
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van Calker D, Biber K. The Role of Glial Adenosine Receptors in Neural Resilience and the Neurobiology of Mood Disorders. Neurochem Res 2005; 30:1205-17. [PMID: 16341582 DOI: 10.1007/s11064-005-8792-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2005] [Indexed: 10/25/2022]
Abstract
Adenosine receptors were classified into A1- and A2-receptors in the laboratory of Bernd Hamprecht more than 25 years ago. Adenosine receptors are instrumental to the neurotrophic effects of glia cells. Both microglia and astrocytes release after stimulation via adenosine receptors factors that are important for neuronal survival and growth. Neuronal resilience is now considered as of pivotal importance in the neurobiology of mood disorders and their treatment. Both sleep deprivation and electroconvulsive therapy, two effective therapeutic measures in mood disorders, are associated with an increase of adenosine and upregulation of adenosine A1-receptors in the brain. Parameters closely related to adenosine receptor activation such as cerebral metabolic rate and delta power in the sleep EEG provide indirect evidence that adenosinergic signaling may be associated with the therapeutic response to these measures. Thus, neurotrophic effects evoked by adenosine receptors might be important in the mechanism of action of ECT and perhaps also sleep deprivation.
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Affiliation(s)
- Dietrich van Calker
- Department of Psychiatry and Psychotherapy, University of Freiburg, D-79104 Freiburg, Germany.
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32
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Rathbone MP, Middlemiss PJ, Crocker CE, Glasky MS, Juurlink BH, Ramirez JJ, Ciccarelli R, Di Iorio P, Caciagli F. AIT-082 as a potential neuroprotective and regenerative agent in stroke and central nervous system injury. Expert Opin Investig Drugs 2005; 8:1255-62. [PMID: 15992149 DOI: 10.1517/13543784.8.8.1255] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The synthetic purine 4-[[3-(1,6 dihydro-6-oxo-9-purin-9-yl)-1-oxypropyl] amino] benzoic acid (AIT-082, Neotrofin, leteprinim potassium) possesses several biological properties of note: it stimulates outgrowth of neurites from PC12 cells and neurones, stimulates synthesis and/or release of neurotrophic factors from astrocytes, enhances nerve fibre regeneration in vivo and enhances of memory in animals and humans. AIT-082 also protects against glutamate neurotoxicity in vitro and in vivo, which has led to successful tests of AIT-082 in animal models of acute central nervous system injury. In such cases, AIT-082 probably functions by both acutely reducing glutamate excitotoxicity and, over a longer period, by enhancing neuronal sprouting and functional recovery.
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Affiliation(s)
- M P Rathbone
- Department of Medicine, McMaster University Health Sciences Center, Hamilton, ON L8N 2S1, Canada.
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33
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Traversa U, Bombi G, Camaioni E, Macchiarulo A, Costantino G, Palmieri C, Caciagli F, Pellicciari R. Rat brain guanosine binding site. Biological studies and pseudo-receptor construction. Bioorg Med Chem 2004; 11:5417-25. [PMID: 14642586 DOI: 10.1016/j.bmc.2003.09.043] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Rat brain guanosine binding sites were studied by (i). a pharmacological approach to confirm the hypothesis of the existence of specific G-coupled receptors for guanosine (1) and, for the first time, delineate a structure-activity relationship for a series of guanosine derivatives; (ii). a molecular modelling approach to design a pseudo-receptor construction. GTP and its non-hydrolysable analogue Gpp[NH]p decreased [3H]-guanosine binding to rat brain membranes. Gpp[NH]p 30 and 100 microM induced a dose-dependent decrease in [3H]-guanosine affinity and PTX pretreatment of rat brain membranes caused a 50% reduction in binding. In slices from rat brain cortex, guanosine induced a dose-dependent increase in intracellular cAMP. This increase is specific for guanosine, since neither the pretreatment with adenosine deaminase nor the A(1) and A(2) adenosine receptor antagonists were able to modify the guanosine-induced cAMP accumulation. The structure-activity relationship showed that the potency order of the best substances able to displace 50 nM [3H]-guanosine was guanosine (1)=6-thioguanosine (3)>8-bromoguanosine (4)>inosine (10)>7-methylguanosine (6)=3'-deoxyguanosine (9)>2'-deoxyguanosine (8)=guanine (11)=6-thioguanine (12)>>N(2)-methylguanosine (5). The competition studies confirmed that [3H]-guanosine site was distinct from the well characterized ATP and adenosine binding sites. The present results are rationalized in terms of a putative pseudo-receptor construct which includes all the relevant physicochemical interaction between guanosine analogues and their putative binding sites. This construct will be useful for the in silico screening of compound libraries in search for new potent and structurally diverse pharmacological tools.
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Affiliation(s)
- Ugo Traversa
- Dipartimento di Scienze Biomediche - BRAIN Center, via L Giorgieri 7, Università di Trieste, 34127 Trieste, Italy
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Di Iorio P, Ballerini P, Traversa U, Nicoletti F, D'Alimonte I, Kleywegt S, Werstiuk ES, Rathbone MP, Caciagli F, Ciccarelli R. The antiapoptotic effect of guanosine is mediated by the activation of the PI 3-kinase/AKT/PKB pathway in cultured rat astrocytes. Glia 2004; 46:356-68. [PMID: 15095366 DOI: 10.1002/glia.20002] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Guanosine has many trophic effects in the CNS, including the stimulation of neurotrophic factor synthesis and release by astrocytes, which protect neurons against excitotoxic death. Therefore, we questioned whether guanosine protected astrocytes against apoptosis induced by staurosporine. We evaluated apoptosis in cultured rat brain astrocytes, following exposure (3 h) to 100 nM staurosporine by acridine orange staining or by oligonucleosome, or caspase-3 ELISA assays. Staurosporine promoted apoptosis rapidly, reaching its maximal effect (approximately 10-fold over basal apoptotic values) in 18-24 h after its administration to astrocytes. Guanosine, added to the culture medium for 4 h, starting from 1 h prior to staurosporine, reduced the proportion of apoptotic cells in a concentration-dependent manner. The IC50 value for the inhibitory effect of guanosine is 7.5 x 10(-5) M. The protective effect of guanosine was not affected by inhibiting the nucleoside transporters by propentophylline, or by the selective antagonists of the adenosine A1 or A2 receptors (DPCPX or DMPX), or by an antagonist of the P2X and P2Y purine receptors (suramin). In contrast, pretreatment of astrocytes with pertussis toxin, which uncouples Gi-proteins from their receptors, abolished the antiapoptotic effect of guanosine. The protective effect of guanosine was also reduced by pretreatment of astrocytes with inhibitors of the phosphoinositide 3-kinase (PI3K; LY294002, 30 microM) or the MAPK pathway (PD98059, 10 microM). Addition of guanosine caused a rapid phosphorylation of Akt/PKB, and glycogen synthase kinase-3beta (GSK-3beta) and induced an upregulation of Bcl-2 mRNA and protein expression. These data demonstrate that guanosine protects astrocytes against staurosporine-induced apoptosis by activating multiple pathways, and these are mediated by a Gi-protein-coupled putative guanosine receptor.
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Affiliation(s)
- Patrizia Di Iorio
- Department of Biomedical Sciences, School of Medicine, University of Chieti, Chieti, Italy
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35
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Pietrangelo T, Mariggiò MA, Lorenzon P, Fulle S, Protasi F, Rathbone M, Werstiuk E, Fanò G. Characterization of specific GTP binding sites in C2C12 mouse skeletal muscle cells. J Muscle Res Cell Motil 2003; 23:107-18. [PMID: 12416717 DOI: 10.1023/a:1020288117082] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Receptor sites, specific for guanosine 5'-triphosphate (GTP) were characterised in myoblasts and myotubes of C2C12 mouse skeletal muscle cells, using binding experiments and measurements of intracellular Ca2+ concentration ([Ca2+]i). We identified two GTP binding sites in myoblasts membranes: a high affinity site (Kd = 15.4 +/- 4.6 microM; Bmax = 1.7 +/- 0.5 nmol mg(-1) protein); and a low affinity site (Kd = 170 +/- 94.5 microM; Bmax = 14.2 +/- 3.9 nmol mg(-1) protein). In myotube membranes only a low affinity binding site for GTP (Kd = 169 +/- 39 microM; Bmax = 12.3 +/- 1.4 nmol mg(-1) protein) was detected. In myoblasts GTP binding was not displaced by ATP or UTP, even at high concentrations (up to of 1 mM), but it was affected by treatments with suramin or Reactive Blue 2 (RB2), the non-selective purine receptor antagonists. In contrast, in myotubes GTP binding was partially displaced by high concentrations of ATP, but treatments with the non-selective purine receptor antagonists, suramin or RB2, and with UTP had no effect on GTP binding. The addition of GTP to myoblasts, and to myotubes, resulted in elevations of [Ca2+]i. The patterns of Ca2+ response however, were different in the two cell phenotypes. In myoblasts the addition of GTP induced two types of Ca2+ responses: (1) a fast increase in [Ca2+]i, followed by a sustained [Ca2+]i elevation, and (2) a slow raising and steady prolonged increase in [Ca2+]i. In myotubes, however only fast Ca2+ responses were observed following the addition of 500 microM GTP. In the myoblasts and myotubes GTP-stimulated [Ca2+]i increases were abolished by treatments with suramin or RB2 at concentrations which had no effect on the ATP-induced Ca2+ responses. We conclude, that C2C12 cells express two distinct binding sites for GTP before differentiation, but only one after, the low affinity binding site. These results suggest a possible role of the high affinity GTP binding site in early stage of development of skeletal muscle.
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Affiliation(s)
- Tiziana Pietrangelo
- Dipartimento di Scienze del Farmaco, Università G. d'Annunzio, Chieti, Italy
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Di Iorio P, Kleywegt S, Ciccarelli R, Traversa U, Andrew CM, Crocker CE, Werstiuk ES, Rathbone MP. Mechanisms of apoptosis induced by purine nucleosides in astrocytes. Glia 2002; 38:179-90. [PMID: 11968056 DOI: 10.1002/glia.10055] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Astrocytes release adenine-based and guanine-based purines under physiological and, particularly, pathological conditions. Thus, the aim of this study was to determine if adenosine induced apoptosis in cultured rat astrocytes. Further, if guanosine, which increases the extracellular concentration of adenosine, also induced apoptosis determined using the TUNEL and Annexin V assays. Adenosine induced apoptosis in a concentration-dependent manner up to 100 microM. Inosine, hypoxanthine, guanine, and guanosine did not. Guanosine or adenosine (100 microM) added to the culture medium was metabolized, with 35% or 15%, respectively, remaining after 2-3 h. Guanosine evoked the extracellular accumulation of adenosine, and particularly of adenine-based nucleotides. Cotreatment with EHNA and guanosine increased the extracellular accumulation of adenosine and induced apoptosis. Inhibition of the nucleoside transporters using NBTI (100 microM) or propentophylline (100 microM) significantly decreased but did not abolish the apoptosis induced by guanosine + EHNA or adenosine + EHNA, respectively. Apoptosis produced by either guanosine + EHNA or adenosine + EHNA was unaffected by A(1) or A(2) adenosine receptor antagonists, but was significantly reduced by MRS 1523, a selective A(3) adenosine receptor antagonist. Adenosine + EHNA, not guanosine + EHNA, significantly increased the intracellular concentration of S-adenosyl-L-homocysteine (SAH) and greatly reduced the ratio of S-adenosyl-L-methioine to SAH, which is associated with apoptosis. These data demonstrate that adenosine mediates apoptosis of astrocytes both, via activation of A(3) adenosine receptors and by modulating SAH hydrolase activity. Guanosine induces apoptosis by accumulating extracellular adenosine, which then acts solely via A(3) adenosine receptors.
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Affiliation(s)
- Patrizia Di Iorio
- Department of Biomedical Sciences, School of Medicine, University of Chieti, Italy
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Traversa U, Bombi G, Di Iorio P, Ciccarelli R, Werstiuk ES, Rathbone MP. Specific [(3)H]-guanosine binding sites in rat brain membranes. Br J Pharmacol 2002; 135:969-76. [PMID: 11861325 PMCID: PMC1573206 DOI: 10.1038/sj.bjp.0704542] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2001] [Revised: 11/27/2001] [Accepted: 11/30/2001] [Indexed: 11/08/2022] Open
Abstract
1. Extracellular guanosine has diverse effects on many cellular components of the central nervous system, some of which may be related to its uptake into cells and others to its ability to release adenine-based purines from cells. Yet other effects of extracellular guanosine are compatible with an action on G-protein linked cell membrane receptors. 2. Specific binding sites for [(3)H]-guanosine were detected on membrane preparations from rat brain. The kinetics of [(3)H]-guanosine binding to membranes was described by rate constants of association and dissociation of 2.6122 x 10(7) M(-1) min(-1) and 1.69 min(-1), respectively. A single high affinity binding site for [(3)H]-guanosine with a K(D) of 95.4 +/- 11.9 nM and B(max) of 0.57 +/- 0.03 pmol mg(-1) protein was shown. This site was specific for guanosine, and the order of potency in displacing 50 nM [(3)H]-guanosine was: guanosine=6-thio-guanosine > inosine > 6-thio-guanine > guanine. Other naturally occurring purines, such as adenosine, hypoxanthine, xanthine caffeine, theophylline, GDP, GMP and ATP were unable to significantly displace the radiolabelled guanosine. Thus, this binding site is distinct from the well-characterized receptors for adenosine and purines. 5. The addition of GTP produced a small concentration-dependent decrease in guanosine binding, suggesting this guanosine binding site was linked to a G-protein. 6. Our results therefore are consistent with the existence of a novel cell membrane receptor site, specific for guanosine.
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Affiliation(s)
- Ugo Traversa
- Department of Biomedical Sciences--Basic Research and Integrative Neuroscience Centre, University of Trieste, via Licio Giorgieri 7, 34127 Trieste, Italy.
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Ciccarelli R, Ballerini P, Sabatino G, Rathbone MP, D'Onofrio M, Caciagli F, Di Iorio P. Involvement of astrocytes in purine‐mediated reparative processes in the brain. Int J Dev Neurosci 2001; 19:395-414. [PMID: 11378300 DOI: 10.1016/s0736-5748(00)00084-8] [Citation(s) in RCA: 178] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Astrocytes are involved in multiple brain functions in physiological conditions, participating in neuronal development, synaptic activity and homeostatic control of the extracellular environment. They also actively participate in the processes triggered by brain injuries, aimed at limiting and repairing brain damages. Purines may play a significant role in the pathophysiology of numerous acute and chronic disorders of the central nervous system (CNS). Astrocytes are the main source of cerebral purines. They release either adenine-based purines, e.g. adenosine and adenosine triphosphate, or guanine-based purines, e.g. guanosine and guanosine triphosphate, in physiological conditions and release even more of these purines in pathological conditions. Astrocytes express several receptor subtypes of P1 and P2 types for adenine-based purines. Receptors for guanine-based purines are being characterised. Specific ecto-enzymes such as nucleotidases, adenosine deaminase and, likely, purine nucleoside phosphorylase, metabolise both adenine- and guanine-based purines after release from astrocytes. This regulates the effects of nucleotides and nucleosides by reducing their interaction with specific membrane binding sites. Adenine-based nucleotides stimulate astrocyte proliferation by a P2-mediated increase in intracellular [Ca2+] and isoprenylated proteins. Adenosine also, via A2 receptors, may stimulate astrocyte proliferation, but mostly, via A1 and/or A3 receptors, inhibits astrocyte proliferation, thus controlling the excessive reactive astrogliosis triggered by P2 receptors. The activation of A1 receptors also stimulates astrocytes to produce trophic factors, such as nerve growth factor, S100beta protein and transforming growth factor beta, which contribute to protect neurons against injuries. Guanosine stimulates the output of adenine-based purines from astrocytes and in addition it directly triggers these cells to proliferate and to produce large amount of neuroprotective factors. These data indicate that adenine- and guanine-based purines released in large amounts from injured or dying cells of CNS may act as signals to initiate brain repair mechanisms widely involving astrocytes.
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Affiliation(s)
- R Ciccarelli
- Department of Biomedical Sciences, Section of Pharmacology, Via del Vestini Pal. B, 66013, Chieti, Italy.
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Dobolyi A, Reichart A, Szikra T, Nyitrai G, Kékesi KA, Juhász G. Sustained depolarisation induces changes in the extracellular concentrations of purine and pyrimidine nucleosides in the rat thalamus. Neurochem Int 2000; 37:71-9. [PMID: 10781847 DOI: 10.1016/s0197-0186(99)00162-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
ATP and adenosine are well-known neuroactive compounds. Other nucleotides and nucleosides may also be involved in different brain functions. This paper reports on extracellular concentrations of nucleobases and nucleosides (uracil, hypoxanthine, xanthine, uridine, 2'-deoxycytidine, 2'-deoxyuridine, inosine, guanosine, thymidine, adenosine) in response to sustained depolarisation, using in vivo brain microdialysis technique in the rat thalamus. High-potassium solution, the glutamate agonist kainate, and the Na(+)/K(+) ATPase blocker ouabain were applied in the perfusate of microdialysis probes and induced release of various purine and pyrimidine nucleosides. All three types of depolarisation increased the level of hypoxanthine, uridine, inosine, guanosine and adenosine. The levels of measured deoxynucleosides (2'-deoxycytidine, 2'-deoxyuridine and thymidine) decreased or did not change, depending on the type of depolarisation. Kainate-induced changes were TTX insensitive, and ouabain-induced changes for inosine, guanosine, 2'-deoxycytidine and 2'-deoxyuridine were TTX sensitive. In contrast, TTX application without depolarisation decreased the extracellular concentrations of hypoxanthine, uridine, inosine, guanosine and adenosine. Our data suggest that various nucleosides may be released from cells exposed to excessive activity and, thus, support several different lines of research concerning the regulatory roles of nucleosides.
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Affiliation(s)
- A Dobolyi
- Research Group of Neurobiology MTA-ELTE, Hungarian Academy of Sciences, Eötvös Loránd University, H-1088, Budapest, Hungary
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Althaus HH, Richter-Landsberg C. Glial cells as targets and producers of neurotrophins. INTERNATIONAL REVIEW OF CYTOLOGY 2000; 197:203-77. [PMID: 10761118 DOI: 10.1016/s0074-7696(00)97005-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Glial cells fulfill important tasks within the neural network of the central and peripheral nervous systems. The synthesis and secretion of various polypeptidic factors (cytokines) and a number of receptors, with which glial cells are equipped, allow them to communicate with their environment. Evidence has accumulated during recent years that neurotrophins play an important role not only for neurons but also for glial cells. This brief update of some morphological, immunocytochemical, and biochemical characteristics of glial cell lineages conveys our present knowledge about glial cells as targets and producers of neurotrophins under normal and pathological conditions. The chapter discusses the presence of neurotrophin receptors on glial cells, glial cells as producers of neurotrophins, signaling pathways downstream Trk and p75NTR, and the significance of neurotrophins and their receptors for glial cells during development, in cell death and survival, and in neurological disorders.
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Affiliation(s)
- H H Althaus
- AG Neural Regeneration, Max Planck Institute for Experimental Medicine, Göttingen, Germany
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D'Ambrosi N, Cavaliere F, Merlo D, Milazzo L, Mercanti D, Volonté C. Antagonists of P2 receptor prevent NGF-dependent neuritogenesis in PC12 cells. Neuropharmacology 2000; 39:1083-94. [PMID: 10727719 DOI: 10.1016/s0028-3908(99)00213-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The pheochromocytoma PC12 cell line that develops neuronal characteristics of sympathetic cells after treatment with nerve growth factor (NGF) represents a well-established cellular model system for studying NGF signalling. Interesting information on the different mechanistic pathways of NGF can be obtained by adopting the pharmacological approach of inhibiting P2 receptors, expressed in naive PC12 cells and recognised as important biological mediators of neurotransmitters and growth factors. We show here that Basilen Blue, an antagonist of P2 receptor, reversibly prevents NGF-dependent neurite outgrowth with an IC(50) in the 5-10 microM range. Suramin, oxidised-ATP and diisothiocyanatostilbene-disulfonic acid, differently from other purinoceptor ligands, are also effective in this regard. NGF-dependent regeneration and stability of neurites, selected NGF-dependent extracellular and intracellular protein phosphorylations, binding of [(3)H] ATP to PC12 cell membranes are also modulated by Basilen Blue. On the contrary, cell adhesion, cellular duplication, 5'-nucleotidase activity, NGF-induced tyrosine autophosphorylation of TrkA receptors are not affected. NGF furthermore directly modulates the extracellular release of ATP and especially the levels of P2X(2) receptor protein in PC12 cells. In addition, extracellular ATP improves the neuritogenic effect of sub-optimal concentrations of NGF. Our study identifies P2 receptor ligands, particularly Basilen Blue, as useful tools to dissect different NGF-evoked functions, suggesting a mechanistic role for P2 receptors in the signalling pathways of NGF.
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Affiliation(s)
- N D'Ambrosi
- I.R.C.C.S. Santa Lucia, Via Ardeatina 306, 00179, Rome, Italy
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Ciccarelli R, Di Iorio P, D'Alimonte I, Giuliani P, Florio T, Caciagli F, Middlemiss PJ, Rathbone MP. Cultured astrocyte proliferation induced by extracellular guanosine involves endogenous adenosine and is raised by the co-presence of microglia. Glia 2000. [DOI: 10.1002/(sici)1098-1136(20000201)29:3<202::aid-glia2>3.0.co;2-c] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Rathbone MP, Middlemiss PJ, Gysbers JW, Andrew C, Herman MA, Reed JK, Ciccarelli R, Di Iorio P, Caciagli F. Trophic effects of purines in neurons and glial cells. Prog Neurobiol 1999; 59:663-90. [PMID: 10845757 DOI: 10.1016/s0301-0082(99)00017-9] [Citation(s) in RCA: 306] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In addition to their well known roles within cells, purine nucleotides such as adenosine 5' triphosphate (ATP) and guanosine 5' triphosphate (GTP), nucleosides such as adenosine and guanosine and bases, such as adenine and guanine and their metabolic products xanthine and hypoxanthine are released into the extracellular space where they act as intercellular signaling molecules. In the nervous system they mediate both immediate effects, such as neurotransmission, and trophic effects which induce changes in cell metabolism, structure and function and therefore have a longer time course. Some trophic effects of purines are mediated via purinergic cell surface receptors, whereas others require uptake of purines by the target cells. Purine nucleosides and nucleotides, especially guanosine, ATP and GTP stimulate incorporation of [3H]thymidine into DNA of astrocytes and microglia and concomitant mitosis in vitro. High concentrations of adenosine also induce apoptosis, through both activation of cell-surface A3 receptors and through a mechanism requiring uptake into the cells. Extracellular purines also stimulate the synthesis and release of protein trophic factors by astrocytes, including bFGF (basic fibroblast growth factor), nerve growth factor (NGF), neurotrophin-3, ciliary neurotrophic factor and S-100beta protein. In vivo infusion into brain of adenosine analogs stimulates reactive gliosis. Purine nucleosides and nucleotides also stimulate the differentiation and process outgrowth from various neurons including primary cultures of hippocampal neurons and pheochromocytoma cells. A tonic release of ATP from neurons, its hydrolysis by ecto-nucleotidases and subsequent re-uptake by axons appears crucial for normal axonal growth. Guanosine and GTP, through apparently different mechanisms, are also potent stimulators of axonal growth in vitro. In vivo the extracellular concentration of purines depends on a balance between the release of purines from cells and their re-uptake and extracellular metabolism. Purine nucleosides and nucleotides are released from neurons by exocytosis and from both neurons and glia by non-exocytotic mechanisms. Nucleosides are principally released through the equilibratory nucleoside transmembrane transporters whereas nucleotides may be transported through the ATP binding cassette family of proteins, including the multidrug resistance protein. The extracellular purine nucleotides are rapidly metabolized by ectonucleotidases. Adenosine is deaminated by adenosine deaminase (ADA) and guanosine is converted to guanine and deaminated by guanase. Nucleosides are also removed from the extracellular space into neurons and glia by transporter systems. Large quantities of purines, particularly guanosine and, to a lesser extent adenosine, are released extracellularly following ischemia or trauma. Thus purines are likely to exert trophic effects in vivo following trauma. The extracellular purine nucleotide GTP enhances the tonic release of adenine nucleotides, whereas the nucleoside guanosine stimulates tonic release of adenosine and its metabolic products. The trophic effects of guanosine and GTP may depend on this process. Guanosine is likely to be an important trophic effector in vivo because high concentrations remain extracellularly for up to a week after focal brain injury. Purine derivatives are now in clinical trials in humans as memory-enhancing agents in Alzheimer's disease. Two of these, propentofylline and AIT-082, are trophic effectors in animals, increasing production of neurotrophic factors in brain and spinal cord. Likely more clinical uses for purine derivatives will be found; purines interact at the level of signal-transduction pathways with other transmitters, for example, glutamate. They can beneficially modify the actions of these other transmitters.
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Affiliation(s)
- M P Rathbone
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
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Tasca CI, Cardoso LF, Souza DO. Effects of guanine nucleotides on adenosine and glutamate modulation of cAMP levels in optic tectum slices from chicks. Neurochem Int 1999; 34:213-20. [PMID: 10355488 DOI: 10.1016/s0197-0186(99)00006-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glutamate and adenosine both modulate adenylyl cyclase activity through interaction of their specific receptors with stimulatory or inhibitory G-proteins. Guanine nucleotides (GN), which modulate G-protein activity intracellularly, are also involved in the inhibition of glutamate responses, acting from the outside of the cells. We had previously reported that glutamate inhibits adenosine-induced cyclic AMP (cAMP) accumulation in slices obtained from the optic tectum of chicks. In the present study we investigated the interaction of GN with these two neurotransmitters and found that GN inhibit the inhibitory effect of glutamate on adenosine-induced cAMP accumulation and potentiate adenosine-induced cAMP accumulation. These effects were observed with 5'-guanylylimidodiphosphate (GppNHp) or GMP, but not with guanosine (the nucleoside). Besides, these interactions of GN occur via a metabotropic glutamate receptor (mGluR) sensitive to (1 S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (1 S,3R-ACPD) but not to L-2-amino-4-phosphonobutyrate (L-AP4). These effects were partially modulated by a mGluR antagonist, (RS)-alpha-methyl-4-carboxyphenylglycine ((RS)M-CPG), and by an adenosine receptor antagonist, 8-phenyltheophylline. GN only potentiated the adenosine response when adenosine was acting through its receptor positively linked to adenylyl cyclase. Therefore, the data show that guanine nucleotides not only inhibit glutamate-induced responses, but also stimulate adenosine-induced responses, a fact that may contribute to the understanding of the physiological functions of guanine nucleotides.
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Affiliation(s)
- C I Tasca
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil.
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Miyazaki S, Imaizumi M, Abiru T, Machida H. Effects of nucleotides on learning and memory in a Morris water maze test in normal and basal forebrain-lesioned rats. Life Sci 1999; 64:45-52. [PMID: 10027741 DOI: 10.1016/s0024-3205(98)00532-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effects of nucleotides on learning and memory were studied in normal and basal forebrain-lesioned rats using a Morris water maze test. Chronic oral administration of a nucleotide mixture (500 mg/kg), containing an equal weight of the disodium salts of adenosine 5'-monophosphate, guanosine 5'-monophosphate, inosine 5'-monophosphate, cytidine 5'-monophosphate, and uridine 5'-monophosphate facilitated learning acquisition in normal rats. In basal forebrain-lesioned rats, administration of the nucleotide mixture showed a tendency to improve learning acquisition and memory retrieval. In the biochemical studies, no significant changes were observed in brain choline and acetylcholine levels by treatment with the nucleotide mixture at the doses tested in both normal and basal forebrain-lesioned rats. The nucleotides did not affect the monoaminergic systems in normal rats, but did cause some changes in these systems in basal forebrain-lesioned rats. The present studies indicate that nucleotides ameliorate learning and memory processes in normal rats, but not in basal forebrain-lesioned rats, and they also modulate the activity of the central monoaminergic systems under certain conditions.
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Affiliation(s)
- S Miyazaki
- Biology Laboratory, Yamasa Corporation, Choshi, Chiba, Japan
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Ciccarelli R, Di Iorio P, Giuliani P, D'Alimonte I, Ballerini P, Caciagli F, Rathbone MP. Rat cultured astrocytes release guanine-based purines in basal conditions and after hypoxia/hypoglycemia. Glia 1999. [DOI: 10.1002/(sici)1098-1136(19990101)25:1<93::aid-glia9>3.0.co;2-n] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abbracchio MP, Burnstock G. Purinergic signalling: pathophysiological roles. JAPANESE JOURNAL OF PHARMACOLOGY 1998; 78:113-45. [PMID: 9829617 DOI: 10.1254/jjp.78.113] [Citation(s) in RCA: 321] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In this review, after a summary of the history and current status of the receptors involved in purinergic signalling, we focus on the distribution and physiological roles of purines and pyrimidines in both short-term events such as neurotransmission, exocrine and endocrine secretion and regulation of immune cell function, and long-term events such as cell growth, differentiation and proliferation in development and regeneration. Finally, the protective roles of nucleosides and nucleotides in events such as cancer, ischemia, wound healing, drug toxicity, inflammation and pain are explored and some suggestions made for future developments in this rapidly expanding field, with particular emphasis on the involvement of selective agonists and antagonists for purinergic receptor subtypes in therapeutic strategies.
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Affiliation(s)
- M P Abbracchio
- Institute of Pharmacological Sciences, University of Milan, Italy
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Upregulation of the enzyme chain hydrolyzing extracellular ATP after transient forebrain ischemia in the rat. J Neurosci 1998. [PMID: 9634555 DOI: 10.1523/jneurosci.18-13-04891.1998] [Citation(s) in RCA: 153] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A short ischemic period induced by the transient occlusion of major brain arteries induces neuronal damage in selectively vulnerable regions of the hippocampus. Adenosine is considered to be one of the major neuroprotective substances produced in the ischemic brain. It can be released from damaged cells, but it also could be generated extracellularly from released ATP via a surface-located enzyme chain. Using the rat model of global forebrain ischemia, we applied a short (10 min) transient interruption of blood flow and studied the distribution of ectonucleotidase activities in the hippocampus. Northern hybridization of mRNA isolated from hippocampi of sham-operated and ischemic animals revealed an upregulation of ectoapyrase (capable of hydrolyzing nucleoside 5'-tri- and diphosphates) and ecto-5'-nucleotidase (capable of hydrolyzing nucleoside 5'-monophosphates). A histochemical analysis that used ATP, UTP, ADP, or AMP as substrates revealed a strong and selective increase in enzyme activity in the injured areas of the hippocampus. Enhanced staining could be observed first at 2 d. Staining increased within the next days and persisted at 28 d after ischemia. The spatiotemporal development of catalytic activities was identical for all substrates. It was most pronounced in the CA1 subfield and also could be detected in the dentate hilus and to a marginal extent in CA3. The histochemical staining corresponded closely to the development of markers for reactive glia, in particular of microglia. The upregulation of ectonucleotidase activities implies increased nucleotide release from the damaged tissue and could play a role in the postischemic control of nucleotide-mediated cellular responses.
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Tasca CI, Cardoso LF, Martini LH, Ramírez G, Souza DO. Guanine nucleotides inhibit cAMP accumulation induced by metabotropic glutamate receptor activation. Neurochem Res 1998; 23:183-8. [PMID: 9475513 DOI: 10.1023/a:1022480825290] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Metabotropic glutamate receptors (mGluRs) have been shown to modulate adenylate cyclase activity via G-proteins. In the present study we report similar results to the previously observed in the literature, showing that glutamate and the metabotropic agonists, 1S,3R-ACPD or quisqualate induced cAMP accumulation in hippocampal slices of young rats. Moreover, guanine nucleotides GTP, GDP or GMP, inhibited the glutamate-induced cAMP accumulation. By measuring LDH activity in the buffer surrounding the slices, we showed that the integrity of the slices was maintained, indicating that the effect of guanine nucleotides was extracellular. GMP, GDPbeta-S or Gpp(NH)p abolished quisqualate-induced cAMP accumulation. GDPbeta-S or Gpp(NH)p but not GMP inhibited 1S,3R-ACPD-induced cAMP accumulation. The response evoked by glutamate was also abolished by the mGluR antagonists: L-AP3 abolished glutamate-induced cAMP accumulation in a dose-dependent manner and MCPG was effective only at the 2 mM dose. DNQX was ineffective. We are reporting here, an inhibition induced by guanine nucleotides, via an extracellular site (s), similar to the observed with classical glutamate antagonists on a cellular response evoked by mGluR agonists.
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Affiliation(s)
- C I Tasca
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, Florianópolis, SC, Brasil
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