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Memory Enhancers for Alzheimer's Dementia: Focus on cGMP. Pharmaceuticals (Basel) 2021; 14:ph14010061. [PMID: 33451088 PMCID: PMC7828493 DOI: 10.3390/ph14010061] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 01/07/2021] [Accepted: 01/12/2021] [Indexed: 02/06/2023] Open
Abstract
Cyclic guanosine-3',5'-monophosphate, better known as cyclic-GMP or cGMP, is a classical second messenger involved in a variety of intracellular pathways ultimately controlling different physiological functions. The family of guanylyl cyclases that includes soluble and particulate enzymes, each of which comprises several isoforms with different mechanisms of activation, synthesizes cGMP. cGMP signaling is mainly executed by the activation of protein kinase G and cyclic nucleotide gated channels, whereas it is terminated by its hydrolysis to GMP operated by both specific and dual-substrate phosphodiesterases. In the central nervous system, cGMP has attracted the attention of neuroscientists especially for its key role in the synaptic plasticity phenomenon of long-term potentiation that is instrumental to memory formation and consolidation, thus setting off a "gold rush" for new drugs that could be effective for the treatment of cognitive deficits. In this article, we summarize the state of the art on the neurochemistry of the cGMP system and then review the pre-clinical and clinical evidence on the use of cGMP enhancers in Alzheimer's disease (AD) therapy. Although preclinical data demonstrates the beneficial effects of cGMP on cognitive deficits in AD animal models, the results of the clinical studies carried out to date are not conclusive. More trials with a dose-finding design on selected AD patient's cohorts, possibly investigating also combination therapies, are still needed to evaluate the clinical potential of cGMP enhancers.
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Gulisano W, Melone M, Ripoli C, Tropea MR, Li Puma DD, Giunta S, Cocco S, Marcotulli D, Origlia N, Palmeri A, Arancio O, Conti F, Grassi C, Puzzo D. Neuromodulatory Action of Picomolar Extracellular Aβ42 Oligomers on Presynaptic and Postsynaptic Mechanisms Underlying Synaptic Function and Memory. J Neurosci 2019; 39:5986-6000. [PMID: 31127002 PMCID: PMC6650983 DOI: 10.1523/jneurosci.0163-19.2019] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 04/09/2019] [Accepted: 04/28/2019] [Indexed: 01/01/2023] Open
Abstract
Failure of anti-amyloid-β peptide (Aβ) therapies against Alzheimer's disease (AD), a neurodegenerative disorder characterized by high amounts of the peptide in the brain, raised the question of the physiological role of Aβ released at low concentrations in the healthy brain. To address this question, we studied the presynaptic and postsynaptic mechanisms underlying the neuromodulatory action of picomolar amounts of oligomeric Aβ42 (oAβ42) on synaptic glutamatergic function in male and female mice. We found that 200 pm oAβ42 induces an increase of frequency of miniature EPSCs and a decrease of paired pulse facilitation, associated with an increase in docked vesicle number, indicating that it augments neurotransmitter release at presynaptic level. oAβ42 also produced postsynaptic changes as shown by an increased length of postsynaptic density, accompanied by an increased expression of plasticity-related proteins such as cAMP-responsive element binding protein phosphorylated at Ser133, calcium-calmodulin-dependent kinase II phosphorylated at Thr286, and brain-derived neurotrophic factor, suggesting a role for Aβ in synaptic tagging. These changes resulted in the conversion of early into late long-term potentiation through the nitric oxide/cGMP/protein kinase G intracellular cascade consistent with a cGMP-dependent switch from short- to long-term memory observed in vivo after intrahippocampal administration of picomolar amounts of oAβ42 These effects were present upon extracellular but not intracellular application of the peptide and involved α7 nicotinic acetylcholine receptors. These observations clarified the physiological role of oAβ42 in synaptic function and memory formation providing solid fundamentals for investigating the pathological effects of high Aβ levels in the AD brains.SIGNIFICANCE STATEMENT High levels of oligomeric amyloid-β42 (oAβ42) induce synaptic dysfunction leading to memory impairment in Alzheimer's disease (AD). However, at picomolar concentrations, the peptide is needed to ensure long-term potentiation (LTP) and memory. Here, we show that extracellular 200 pm oAβ42 concentrations increase neurotransmitter release, number of docked vesicles, postsynaptic density length, and expression of plasticity-related proteins leading to the conversion of early LTP into late LTP and of short-term memory into long-term memory. These effects require α7 nicotinic acetylcholine receptors and are mediated through the nitric oxide/cGMP/protein kinase G pathway. The knowledge of Aβ function in the healthy brain might be useful to understand the causes leading to its increase and detrimental effect in AD.
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Affiliation(s)
- Walter Gulisano
- Department Biomedical and Biotechnological Sciences, University of Catania, Catania 95123, Italy
| | - Marcello Melone
- Section of Neuroscience and Cell Biology, Department Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona 60020, Italy
- Center for Neurobiology of Aging, IRCCS Istituto Nazionale Ricovero e Cura Anziani (INRCA), Ancona 60020, Italy
| | - Cristian Ripoli
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome 00168, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome 00168, Italy
| | - Maria Rosaria Tropea
- Department Biomedical and Biotechnological Sciences, University of Catania, Catania 95123, Italy
| | - Domenica D Li Puma
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome 00168, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome 00168, Italy
| | - Salvatore Giunta
- Department Biomedical and Biotechnological Sciences, University of Catania, Catania 95123, Italy
| | - Sara Cocco
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome 00168, Italy
| | - Daniele Marcotulli
- Section of Neuroscience and Cell Biology, Department Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona 60020, Italy
| | - Nicola Origlia
- Neuroscience Institute, Italian National Research Council, Pisa 56100, Italy
| | - Agostino Palmeri
- Department Biomedical and Biotechnological Sciences, University of Catania, Catania 95123, Italy
| | - Ottavio Arancio
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York 10032
| | - Fiorenzo Conti
- Section of Neuroscience and Cell Biology, Department Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona 60020, Italy
- Center for Neurobiology of Aging, IRCCS Istituto Nazionale Ricovero e Cura Anziani (INRCA), Ancona 60020, Italy
- Foundation for Molecular Medicine, Università Politecnica delle Marche, Ancona 60020, Italy, and
| | - Claudio Grassi
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome 00168, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome 00168, Italy
| | - Daniela Puzzo
- Department Biomedical and Biotechnological Sciences, University of Catania, Catania 95123, Italy,
- Oasi Research Institute-IRCCS, Troina, 94018, Italy
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O'Brart NAL, O'Brart DPS, Aldahlawi NH, Hayes S, Meek KM. An Investigation of the Effects of Riboflavin Concentration on the Efficacy of Corneal Cross-Linking Using an Enzymatic Resistance Model in Porcine Corneas. Invest Ophthalmol Vis Sci 2018; 59:1058-1065. [PMID: 29490342 PMCID: PMC6436846 DOI: 10.1167/iovs.17-22994] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Purpose To investigate riboflavin concentration on enzymatic resistance following corneal cross-linking (CXL). Methods Ninety-six porcine eyes were divided into five groups in two treatment runs. Group 1 remained untreated. Group 2 received riboflavin 0.05%, group 3 riboflavin 0.1%, group 4 riboflavin 0.2%, and group 5 riboflavin 0.3%. Treated eyes underwent CXL with ultraviolet A at 9 mW/cm2 for 10 minutes. Eight-millimeter discs from each cornea were submerged in pepsin digest solution. In the first run, disc diameters were measured daily. After 10 days, dry weights were recorded from five samples in each group. In the second run, dry weights were recorded in five samples in each group at 10 and 20 days. Results CXL-treated corneas took longer to digest than untreated (P < 0.001). Although eyes treated with higher riboflavin concentrations generally took longer to digest, there were no significant differences between groups (P = 0.3). Dry weights at 10 days demonstrated, with each increase in concentration, an increase in weight of residual undigested tissue (P < 0.001). In the second run, with each increase in riboflavin concentration there was an increase in weight of residual tissue (P < 0.001) at 10 days. At 20 days, the dry weight was lower with 0.05% riboflavin compared to 0.3% (P < 0.001) and 0.2% and 0.1% solutions (P < 0.05), with no other difference between groups. Conclusions There is a consistent dose-response curve with higher concentrations of riboflavin achieving greater CXL efficacy, suggesting that manipulation of riboflavin dosage as well as the UVA protocol can be used to optimize CXL.
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Affiliation(s)
| | - David P S O'Brart
- Keratoconus Research Institute, Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom
| | - Nada H Aldahlawi
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff
| | - Sally Hayes
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff
| | - Keith M Meek
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff
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Gulisano W, Tropea MR, Arancio O, Palmeri A, Puzzo D. Sub-efficacious doses of phosphodiesterase 4 and 5 inhibitors improve memory in a mouse model of Alzheimer's disease. Neuropharmacology 2018; 138:151-159. [PMID: 29885420 DOI: 10.1016/j.neuropharm.2018.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 05/30/2018] [Accepted: 06/03/2018] [Indexed: 01/06/2023]
Abstract
Cyclic nucleotides cAMP and cGMP cooperate to ensure memory acquisition and consolidation. Increasing their levels by phosphodiesterase inhibitors (PDE-Is) enhanced cognitive functions and rescued memory loss in different models of aging and Alzheimer's disease (AD). However, side effects due to the high doses used limited their application in humans. Based on previous studies suggesting that combinations of sub-efficacious doses of cAMP- and cGMP-specific PDE-Is improved synaptic plasticity and memory in physiological conditions, here we aimed to study whether this treatment was effective to counteract the AD phenotype in APPswe mice. We found that a 3-week chronic treatment with a combination of sub-efficacious doses of the cAMP-specific PDE4-I roflumilast (0.01 mg/kg) and the cGMP-specific PDE5-I vardenafil (0.1 mg/kg) improved recognition, spatial and contextual fear memory. Importantly, the cognitive enhancement persisted for 2 months beyond administration. This long-lasting action, and the possibility to minimize side effects due to the low doses used, might open feasible therapeutic strategies against AD.
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Affiliation(s)
- Walter Gulisano
- Dept. Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania, Italy
| | - Maria Rosaria Tropea
- Dept. Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania, Italy
| | - Ottavio Arancio
- Dept. of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Agostino Palmeri
- Dept. Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania, Italy
| | - Daniela Puzzo
- Dept. Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania, Italy.
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Shefa U, Kim D, Kim MS, Jeong NY, Jung J. Roles of Gasotransmitters in Synaptic Plasticity and Neuropsychiatric Conditions. Neural Plast 2018; 2018:1824713. [PMID: 29853837 PMCID: PMC5960547 DOI: 10.1155/2018/1824713] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 02/25/2018] [Accepted: 03/11/2018] [Indexed: 12/22/2022] Open
Abstract
Synaptic plasticity is important for maintaining normal neuronal activity and proper neuronal functioning in the nervous system. It is crucial for regulating synaptic transmission or electrical signal transduction to neuronal networks, for sharing essential information among neurons, and for maintaining homeostasis in the body. Moreover, changes in synaptic or neural plasticity are associated with many neuropsychiatric conditions, such as schizophrenia (SCZ), bipolar disorder (BP), major depressive disorder (MDD), and Alzheimer's disease (AD). The improper maintenance of neural plasticity causes incorrect neurotransmitter transmission, which can also cause neuropsychiatric conditions. Gas neurotransmitters (gasotransmitters), such as hydrogen sulfide (H2S), nitric oxide (NO), and carbon monoxide (CO), play roles in maintaining synaptic plasticity and in helping to restore such plasticity in the neuronal architecture in the central nervous system (CNS). Indeed, the upregulation or downregulation of these gasotransmitters may cause neuropsychiatric conditions, and their amelioration may restore synaptic plasticity and proper neuronal functioning and thereby improve such conditions. Understanding the specific molecular mechanisms underpinning these effects can help identify ways to treat these neuropsychiatric conditions.
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Affiliation(s)
- Ulfuara Shefa
- Department of Biomedical Science, Graduate School, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Dokyoung Kim
- Department of Biomedical Science, Graduate School, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Min-Sik Kim
- Department of Applied Chemistry, College of Applied Science, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 17104, Republic of Korea
| | - Na Young Jeong
- Department of Anatomy and Cell Biology, College of Medicine, Dong-A University, 32 Daesingongwon-ro, Seo-gu, Busan 49201, Republic of Korea
| | - Junyang Jung
- Department of Biomedical Science, Graduate School, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
- East-West Medical Research Institute, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, 13 Seoul 02447, Republic of Korea
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