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Donders Z, Skorupska IJ, Willems E, Mussen F, Broeckhoven JV, Carlier A, Schepers M, Vanmierlo T. Beyond PDE4 inhibition: A comprehensive review on downstream cAMP signaling in the central nervous system. Biomed Pharmacother 2024; 177:117009. [PMID: 38908196 DOI: 10.1016/j.biopha.2024.117009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/27/2024] [Accepted: 06/17/2024] [Indexed: 06/24/2024] Open
Abstract
Cyclic adenosine monophosphate (cAMP) is a key second messenger that regulates signal transduction pathways pivotal for numerous biological functions. Intracellular cAMP levels are spatiotemporally regulated by their hydrolyzing enzymes called phosphodiesterases (PDEs). It has been shown that increased cAMP levels in the central nervous system (CNS) promote neuroplasticity, neurotransmission, neuronal survival, and myelination while suppressing neuroinflammation. Thus, elevating cAMP levels through PDE inhibition provides a therapeutic approach for multiple CNS disorders, including multiple sclerosis, stroke, spinal cord injury, amyotrophic lateral sclerosis, traumatic brain injury, and Alzheimer's disease. In particular, inhibition of the cAMP-specific PDE4 subfamily is widely studied because of its high expression in the CNS. So far, the clinical translation of full PDE4 inhibitors has been hampered because of dose-limiting side effects. Hence, focusing on signaling cascades downstream activated upon PDE4 inhibition presents a promising strategy, offering novel and pharmacologically safe targets for treating CNS disorders. Yet, the underlying downstream signaling pathways activated upon PDE(4) inhibition remain partially elusive. This review provides a comprehensive overview of the existing knowledge regarding downstream mediators of cAMP signaling induced by PDE4 inhibition or cAMP stimulators. Furthermore, we highlight existing gaps and future perspectives that may incentivize additional downstream research concerning PDE(4) inhibition, thereby providing novel therapeutic approaches for CNS disorders.
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Affiliation(s)
- Zoë Donders
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht 6229ER, the Netherlands; Department of Neuroscience, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Hasselt 3500, Belgium
| | - Iga Joanna Skorupska
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht 6229ER, the Netherlands; Department of Neuroscience, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Hasselt 3500, Belgium; Department of Cell Biology-Inspired Tissue Engineering, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht 6629ER, the Netherlands
| | - Emily Willems
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht 6229ER, the Netherlands; Department of Neuroscience, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Hasselt 3500, Belgium
| | - Femke Mussen
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht 6229ER, the Netherlands; Department of Neuroscience, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Hasselt 3500, Belgium; Department of Immunology and Infection, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Hasselt 3500, Belgium
| | - Jana Van Broeckhoven
- Department of Immunology and Infection, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Hasselt 3500, Belgium; University MS Centre (UMSC) Hasselt - Pelt, Belgium
| | - Aurélie Carlier
- Department of Cell Biology-Inspired Tissue Engineering, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht 6629ER, the Netherlands
| | - Melissa Schepers
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht 6229ER, the Netherlands; Department of Neuroscience, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Hasselt 3500, Belgium; University MS Centre (UMSC) Hasselt - Pelt, Belgium
| | - Tim Vanmierlo
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht 6229ER, the Netherlands; Department of Neuroscience, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Hasselt 3500, Belgium; University MS Centre (UMSC) Hasselt - Pelt, Belgium.
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Aparicio JG, Hopp H, Harutyunyan N, Stewart C, Cobrinik D, Borchert M. Aberrant gene expression yet undiminished retinal ganglion cell genesis in iPSC-derived models of optic nerve hypoplasia. Ophthalmic Genet 2024; 45:1-15. [PMID: 37807874 PMCID: PMC10841193 DOI: 10.1080/13816810.2023.2253902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 08/26/2023] [Indexed: 10/10/2023]
Abstract
BACKGROUND Optic nerve hypoplasia (ONH), the leading congenital cause of permanent blindness, is characterized by a retinal ganglion cell (RGC) deficit at birth. Multifactorial developmental events are hypothesized to underlie ONH and its frequently associated neurologic and endocrine abnormalities; however, environmental influences are unclear and genetic underpinnings are unexplored. This work investigates the genetic contribution to ONH RGC production and gene expression using patient induced pluripotent stem cell (iPSC)-derived retinal organoids (ROs). MATERIALS AND METHODS iPSCs produced from ONH patients and controls were differentiated to ROs. RGC genesis was assessed using immunofluorescence and flow cytometry. Flow-sorted BRN3+ cells were collected for RNA extraction for RNA-Sequencing. Differential gene expression was assessed using DESeq2 and edgeR. PANTHER was employed to identify statistically over-represented ontologies among the differentially expressed genes (DEGs). DEGs of high interest to ONH were distinguished by assessing function, mutational constraint, and prior identification in ONH, autism and neurodevelopmental disorder (NDD) studies. RESULTS RGC genesis and survival were similar in ONH and control ROs. Differential expression of 70 genes was identified in both DESeq2 and edgeR analyses, representing a ~ 4-fold higher percentage of DEGs than in randomized study participants. DEGs showed trends towards over-representation of validated NDD genes and ONH exome variant genes. Among the DEGs, RAPGEF4 and DMD had the greatest number of disease-relevant features. CONCLUSIONS ONH genetic background was not associated with impaired RGC genesis but was associated with DEGs exhibiting disease contribution potential. This constitutes some of the first evidence of a genetic contribution to ONH.
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Affiliation(s)
- Jennifer G. Aparicio
- The Vision Center and The Saban Research Institute,
Children’s Hospital Los Angeles, Los Angeles, CA, USA
| | - Hanno Hopp
- The Vision Center and The Saban Research Institute,
Children’s Hospital Los Angeles, Los Angeles, CA, USA
| | - Narine Harutyunyan
- The Vision Center and The Saban Research Institute,
Children’s Hospital Los Angeles, Los Angeles, CA, USA
| | - Carly Stewart
- The Vision Center and The Saban Research Institute,
Children’s Hospital Los Angeles, Los Angeles, CA, USA
| | - David Cobrinik
- The Vision Center and The Saban Research Institute,
Children’s Hospital Los Angeles, Los Angeles, CA, USA
- Department of Biochemistry & Molecular Medicine, Keck
School of Medicine, University of Southern California, Los Angeles, CA, USA
- Norris Comprehensive Cancer Center, Keck School of
Medicine, University of Southern California, Los Angeles, CA, USA
- USC Roski Eye Institute, Department of Ophthalmology, Keck
School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Mark Borchert
- The Vision Center and The Saban Research Institute,
Children’s Hospital Los Angeles, Los Angeles, CA, USA
- USC Roski Eye Institute, Department of Ophthalmology, Keck
School of Medicine, University of Southern California, Los Angeles, CA, USA
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Gao J, Khang MK, Liao Z, Webb K, Detloff MR, Lee JS. Rolipram-loaded PgP nanoparticle reduces secondary injury and enhances motor function recovery in a rat moderate contusion SCI model. NANOMEDICINE : NANOTECHNOLOGY, BIOLOGY, AND MEDICINE 2023; 53:102702. [PMID: 37574117 DOI: 10.1016/j.nano.2023.102702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 07/30/2023] [Accepted: 08/02/2023] [Indexed: 08/15/2023]
Abstract
Spinal cord injury (SCI) results in immediate axonal damage and cell death, as well as a prolonged secondary injury consist of a cascade of pathophysiological processes. One important aspect of secondary injury is activation of phosphodiesterase 4 (PDE4) that leads to reduce cAMP levels in the injured spinal cord. We have developed an amphiphilic copolymer, poly (lactide-co-glycolide)-graft-polyethylenimine (PgP) that can deliver Rolipram, the PDE4 inhibitor. The objective of this work was to investigate the effect of rolipram loaded PgP (Rm-PgP) on secondary injury and motor functional recovery in a rat moderate contusion SCI model. We observed that Rm-PgP can increase cAMP level at the lesion site, and reduce secondary injury such as the inflammatory response by macrophages/microglia, astrogliosis by activated astrocytes and apoptosis as well as improve neuronal survival at 4 weeks post-injury (WPI). We also observed that Rm-PgP can improve motor functional recovery after SCI over 4 WPI.
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Affiliation(s)
- Jun Gao
- Drug Design Delivery and Development (4D) Laboratory, Department of Bioengineering, Clemson University, Clemson, SC, USA
| | - Min Kyung Khang
- Drug Design Delivery and Development (4D) Laboratory, Department of Bioengineering, Clemson University, Clemson, SC, USA
| | - Zhen Liao
- Drug Design Delivery and Development (4D) Laboratory, Department of Bioengineering, Clemson University, Clemson, SC, USA.
| | - Ken Webb
- MicroEnvironmental Laboratory, Department of Bioengineering, Clemson University, Clemson, SC, USA.
| | - Megan Ryan Detloff
- Department of Neurobiology & Anatomy, Marion Murray Spinal Cord Research Center, College of Medicine, Drexel University, Philadelphia, PA 19129, USA.
| | - Jeoung Soo Lee
- Drug Design Delivery and Development (4D) Laboratory, Department of Bioengineering, Clemson University, Clemson, SC, USA.
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Mussen F, Broeckhoven JV, Hellings N, Schepers M, Vanmierlo T. Unleashing Spinal Cord Repair: The Role of cAMP-Specific PDE Inhibition in Attenuating Neuroinflammation and Boosting Regeneration after Traumatic Spinal Cord Injury. Int J Mol Sci 2023; 24:ijms24098135. [PMID: 37175842 PMCID: PMC10179671 DOI: 10.3390/ijms24098135] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 04/27/2023] [Accepted: 04/29/2023] [Indexed: 05/15/2023] Open
Abstract
Traumatic spinal cord injury (SCI) is characterized by severe neuroinflammation and hampered neuroregeneration, which often leads to permanent neurological deficits. Current therapies include decompression surgery, rehabilitation, and in some instances, the use of corticosteroids. However, the golden standard of corticosteroids still achieves minimal improvements in functional outcomes. Therefore, new strategies tackling the initial inflammatory reactions and stimulating endogenous repair in later stages are crucial to achieving functional repair in SCI patients. Cyclic adenosine monophosphate (cAMP) is an important second messenger in the central nervous system (CNS) that modulates these processes. A sustained drop in cAMP levels is observed during SCI, and elevating cAMP is associated with improved functional outcomes in experimental models. cAMP is regulated in a spatiotemporal manner by its hydrolyzing enzyme phosphodiesterase (PDE). Growing evidence suggests that inhibition of cAMP-specific PDEs (PDE4, PDE7, and PDE8) is an important strategy to orchestrate neuroinflammation and regeneration in the CNS. Therefore, this review focuses on the current evidence related to the immunomodulatory and neuroregenerative role of cAMP-specific PDE inhibition in the SCI pathophysiology.
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Affiliation(s)
- Femke Mussen
- Department of Neuroscience, Biomedical Research Institute BIOMED, Hasselt University, 3590 Diepenbeek, Belgium
- University MS Center (UMSC) Hasselt-Pelt, Hasselt University, 3500 Hasselt, Belgium
| | - Jana Van Broeckhoven
- University MS Center (UMSC) Hasselt-Pelt, Hasselt University, 3500 Hasselt, Belgium
- Department of Immunology and Infection, Biomedical Research Institute BIOMED, Hasselt University, 3590 Diepenbeek, Belgium
| | - Niels Hellings
- University MS Center (UMSC) Hasselt-Pelt, Hasselt University, 3500 Hasselt, Belgium
- Department of Immunology and Infection, Biomedical Research Institute BIOMED, Hasselt University, 3590 Diepenbeek, Belgium
| | - Melissa Schepers
- Department of Neuroscience, Biomedical Research Institute BIOMED, Hasselt University, 3590 Diepenbeek, Belgium
- University MS Center (UMSC) Hasselt-Pelt, Hasselt University, 3500 Hasselt, Belgium
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, 6229ER Maastricht, The Netherlands
| | - Tim Vanmierlo
- Department of Neuroscience, Biomedical Research Institute BIOMED, Hasselt University, 3590 Diepenbeek, Belgium
- University MS Center (UMSC) Hasselt-Pelt, Hasselt University, 3500 Hasselt, Belgium
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, 6229ER Maastricht, The Netherlands
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Dorrian RM, Berryman CF, Lauto A, Leonard AV. Electrical stimulation for the treatment of spinal cord injuries: A review of the cellular and molecular mechanisms that drive functional improvements. Front Cell Neurosci 2023; 17:1095259. [PMID: 36816852 PMCID: PMC9936196 DOI: 10.3389/fncel.2023.1095259] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 01/16/2023] [Indexed: 02/05/2023] Open
Abstract
Spinal cord injury (SCI) is a devastating condition that causes severe loss of motor, sensory and autonomic functions. Additionally, many individuals experience chronic neuropathic pain that is often refractory to interventions. While treatment options to improve outcomes for individuals with SCI remain limited, significant research efforts in the field of electrical stimulation have made promising advancements. Epidural electrical stimulation, peripheral nerve stimulation, and functional electrical stimulation have shown promising improvements for individuals with SCI, ranging from complete weight-bearing locomotion to the recovery of sexual function. Despite this, there is a paucity of mechanistic understanding, limiting our ability to optimize stimulation devices and parameters, or utilize combinatorial treatments to maximize efficacy. This review provides a background into SCI pathophysiology and electrical stimulation methods, before exploring cellular and molecular mechanisms suggested in the literature. We highlight several key mechanisms that contribute to functional improvements from electrical stimulation, identify gaps in current knowledge and highlight potential research avenues for future studies.
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Affiliation(s)
- Ryan M. Dorrian
- Spinal Cord Injury Research Group, School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia,*Correspondence: Ryan M. Dorrian,
| | | | - Antonio Lauto
- School of Science, Western Sydney University, Penrith, NSW, Australia
| | - Anna V. Leonard
- Spinal Cord Injury Research Group, School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia
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Costa G, Ribeiro FF, Sebastião AM, Muir EM, Vaz SH. Bridging the gap of axonal regeneration in the central nervous system: A state of the art review on central axonal regeneration. Front Neurosci 2022; 16:1003145. [PMID: 36440273 PMCID: PMC9682039 DOI: 10.3389/fnins.2022.1003145] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/19/2022] [Indexed: 08/26/2023] Open
Abstract
Neuronal regeneration in the central nervous system (CNS) is an important field of research with relevance to all types of neuronal injuries, including neurodegenerative diseases. The glial scar is a result of the astrocyte response to CNS injury. It is made up of many components creating a complex environment in which astrocytes play various key roles. The glial scar is heterogeneous, diverse and its composition depends upon the injury type and location. The heterogeneity of the glial scar observed in different situations of CNS damage and the consequent implications for axon regeneration have not been reviewed in depth. The gap in this knowledge will be addressed in this review which will also focus on our current understanding of central axonal regeneration and the molecular mechanisms involved. The multifactorial context of CNS regeneration is discussed, and we review newly identified roles for components previously thought to solely play an inhibitory role in central regeneration: astrocytes and p75NTR and discuss their potential and relevance for deciding therapeutic interventions. The article ends with a comprehensive review of promising new therapeutic targets identified for axonal regeneration in CNS and a discussion of novel ways of looking at therapeutic interventions for several brain diseases and injuries.
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Affiliation(s)
- Gonçalo Costa
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| | - Filipa F. Ribeiro
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Ana M. Sebastião
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Elizabeth M. Muir
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Sandra H. Vaz
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
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NPC transplantation rescues sci-driven cAMP/EPAC2 alterations, leading to neuroprotection and microglial modulation. Cell Mol Life Sci 2022; 79:455. [PMID: 35904607 PMCID: PMC9338125 DOI: 10.1007/s00018-022-04494-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 07/07/2022] [Accepted: 07/17/2022] [Indexed: 11/17/2022]
Abstract
Neural progenitor cell (NPC) transplantation represents a promising treatment strategy for spinal cord injury (SCI); however, the underlying therapeutic mechanisms remain incompletely understood. We demonstrate that severe spinal contusion in adult rats causes transcriptional dysregulation, which persists from early subacute to chronic stages of SCI and affects nearly 20,000 genes in total tissue extracts. Functional analysis of this dysregulated transcriptome reveals the significant downregulation of cAMP signalling components immediately after SCI, involving genes such as EPAC2 (exchange protein directly activated by cAMP), PKA, BDNF, and CAMKK2. The ectopic transplantation of spinal cord-derived NPCs at acute or subacute stages of SCI induces a significant transcriptional impact in spinal tissue, as evidenced by the normalized expression of a large proportion of SCI-affected genes. The transcriptional modulation pattern driven by NPC transplantation includes the rescued expression of cAMP signalling genes, including EPAC2. We also explore how the sustained in vivo inhibition of EPAC2 downstream signalling via the intrathecal administration of ESI-05 for 1 week impacts therapeutic mechanisms involved in the NPC-mediated treatment of SCI. NPC transplantation in SCI rats in the presence and absence of ESI-05 administration prompts increased rostral cAMP levels; however, NPC and ESI-05 treated animals exhibit a significant reduction in EPAC2 mRNA levels compared to animals receiving only NPCs treatment. Compared with transplanted animals, NPCs + ESI-05 treatment increases the scar area (as shown by GFAP staining), polarizes microglia into an inflammatory phenotype, and increases the magnitude of the gap between NeuN + cells across the lesion. Overall, our results indicate that the NPC-associated therapeutic mechanisms in the context of SCI involve the cAMP pathway, which reduces inflammation and provides a more neuropermissive environment through an EPAC2-dependent mechanism.
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Zhou G, Wang Z, Han S, Chen X, Li Z, Hu X, Li Y, Gao J. Multifaceted Roles of cAMP Signaling in the Repair Process of Spinal Cord Injury and Related Combination Treatments. Front Mol Neurosci 2022; 15:808510. [PMID: 35283731 PMCID: PMC8904388 DOI: 10.3389/fnmol.2022.808510] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 01/26/2022] [Indexed: 01/03/2023] Open
Abstract
Spinal cord injury (SCI) results in multiple pathophysiological processes, including blood–spinal cord barrier disruption, hemorrhage/ischemia, oxidative stress, neuroinflammation, scar formation, and demyelination. These responses eventually lead to severe tissue destruction and an inhibitory environment for neural regeneration.cAMP signaling is vital for neurite outgrowth and axonal guidance. Stimulating intracellular cAMP activity significantly promotes neuronal survival and axonal regrowth after SCI.However, neuronal cAMP levels in adult CNS are relatively low and will further decrease after injury. Targeting cAMP signaling has become a promising strategy for neural regeneration over the past two decades. Furthermore, studies have revealed that cAMP signaling is involved in the regulation of glial cell function in the microenvironment of SCI, including macrophages/microglia, reactive astrocytes, and oligodendrocytes. cAMP-elevating agents in the post-injury milieu increase the cAMP levels in both neurons and glial cells and facilitate injury repair through the interplay between neurons and glial cells and ultimately contribute to better morphological and functional outcomes. In recent years, combination treatments associated with cAMP signaling have been shown to exert synergistic effects on the recovery of SCI. Agents carried by nanoparticles exhibit increased water solubility and capacity to cross the blood–spinal cord barrier. Implanted bioscaffolds and injected hydrogels are potential carriers to release agents locally to avoid systemic side effects. Cell transplantation may provide permissive matrices to synergize with the cAMP-enhanced growth capacity of neurons. cAMP can also induce the oriented differentiation of transplanted neural stem/progenitor cells into neurons and increase the survival rate of cell grafts. Emerging progress focused on cAMP compartmentation provides researchers with new perspectives to understand the complexity of downstream signaling, which may facilitate the clinical translation of strategies targeting cAMP signaling for SCI repair.
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Affiliation(s)
- Gang Zhou
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Zhiyan Wang
- Plastic Surgery Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Shiyuan Han
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xiaokun Chen
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Zhimin Li
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xianghui Hu
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yongning Li
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- Department of International Medical Service, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Jun Gao
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- *Correspondence: Jun Gao
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Melrose J, Hayes AJ, Bix G. The CNS/PNS Extracellular Matrix Provides Instructive Guidance Cues to Neural Cells and Neuroregulatory Proteins in Neural Development and Repair. Int J Mol Sci 2021; 22:ijms22115583. [PMID: 34070424 PMCID: PMC8197505 DOI: 10.3390/ijms22115583] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 05/11/2021] [Accepted: 05/17/2021] [Indexed: 02/07/2023] Open
Abstract
Background. The extracellular matrix of the PNS/CNS is unusual in that it is dominated by glycosaminoglycans, especially hyaluronan, whose space filling and hydrating properties make essential contributions to the functional properties of this tissue. Hyaluronan has a relatively simple structure but its space-filling properties ensure micro-compartments are maintained in the brain ultrastructure, ensuring ionic niches and gradients are maintained for optimal cellular function. Hyaluronan has cell-instructive, anti-inflammatory properties and forms macro-molecular aggregates with the lectican CS-proteoglycans, forming dense protective perineuronal net structures that provide neural and synaptic plasticity and support cognitive learning. Aims. To highlight the central nervous system/peripheral nervous system (CNS/PNS) and its diverse extracellular and cell-associated proteoglycans that have cell-instructive properties regulating neural repair processes and functional recovery through interactions with cell adhesive molecules, receptors and neuroregulatory proteins. Despite a general lack of stabilising fibrillar collagenous and elastic structures in the CNS/PNS, a sophisticated dynamic extracellular matrix is nevertheless important in tissue form and function. Conclusions. This review provides examples of the sophistication of the CNS/PNS extracellular matrix, showing how it maintains homeostasis and regulates neural repair and regeneration.
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Affiliation(s)
- James Melrose
- Raymond Purves Bone and Joint Research Laboratory, Kolling Institute, Northern Sydney Local Health District, St. Leonards, NSW 2065, Australia
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW 2052, Australia
- Sydney Medical School, Northern, The University of Sydney, Sydney, NSW 2052, Australia
- Faculty of Medicine and Health, The University of Sydney, Royal North Shore Hospital, St. Leonards, NSW 2065, Australia
- Correspondence:
| | - Anthony J. Hayes
- Bioimaging Research Hub, Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK;
| | - Gregory Bix
- Clinical Neuroscience Research Center, Departments of Neurosurgery and Neurology, Tulane University School of Medicine, New Orleans, LA 70112, USA;
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Abstract
The well-known second messenger cyclic adenosine monophosphate (cAMP) regulates the morphology and physiology of neurons and thus higher cognitive brain functions. The discovery of exchange protein activated by cAMP (Epac) as a guanine nucleotide exchange factor for Rap GTPases has shed light on protein kinase A (PKA)-independent functions of cAMP signaling in neural tissues. Studies of cAMP-Epac-mediated signaling in neurons under normal and disease conditions also revealed its diverse contributions to neurodevelopment, synaptic remodeling, and neurotransmitter release, as well as learning, memory, and emotion. In this mini-review, the various roles of Epac isoforms, including Epac1 and Epac2, highly expressed in neural tissues are summarized, and controversies or issues are highlighted that need to be resolved to uncover the critical functions of Epac in neural tissues and the potential for a new therapeutic target of mental disorders.
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Affiliation(s)
- Kyungmin Lee
- Laboratory for Behavioral Neural Circuitry and Physiology, Department of Anatomy, Brain Science & Engineering Institute, School of Medicine, Kyungpook National University, Daegu 41944, Korea
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Guijarro-Belmar A, Domanski DM, Bo X, Shewan D, Huang W. The therapeutic potential of targeting exchange protein directly activated by cyclic adenosine 3',5'-monophosphate (Epac) for central nervous system trauma. Neural Regen Res 2021; 16:460-469. [PMID: 32985466 PMCID: PMC7996029 DOI: 10.4103/1673-5374.293256] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Millions of people worldwide are affected by traumatic spinal cord injury, which usually results in permanent sensorimotor disability. Damage to the spinal cord leads to a series of detrimental events including ischaemia, haemorrhage and neuroinflammation, which over time result in further neural tissue loss. Eventually, at chronic stages of traumatic spinal cord injury, the formation of a glial scar, cystic cavitation and the presence of numerous inhibitory molecules act as physical and chemical barriers to axonal regrowth. This is further hindered by a lack of intrinsic regrowth ability of adult neurons in the central nervous system. The intracellular signalling molecule, cyclic adenosine 3′,5′-monophosphate (cAMP), is known to play many important roles in the central nervous system, and elevating its levels as shown to improve axonal regeneration outcomes following traumatic spinal cord injury in animal models. However, therapies directly targeting cAMP have not found their way into the clinic, as cAMP is ubiquitously present in all cell types and its manipulation may have additional deleterious effects. A downstream effector of cAMP, exchange protein directly activated by cAMP 2 (Epac2), is mainly expressed in the adult central nervous system, and its activation has been shown to mediate the positive effects of cAMP on axonal guidance and regeneration. Recently, using ex vivo modelling of traumatic spinal cord injury, Epac2 activation was found to profoundly modulate the post-lesion environment, such as decreasing the activation of astrocytes and microglia. Pilot data with Epac2 activation also suggested functional improvement assessed by in vivo models of traumatic spinal cord injury. Therefore, targeting Epac2 in traumatic spinal cord injury could represent a novel strategy in traumatic spinal cord injury repair, and future work is needed to fully establish its therapeutic potential.
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Affiliation(s)
- Alba Guijarro-Belmar
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen; Sainsbury Wellcome Centre, University College London, London, UK
| | - Dominik Mateusz Domanski
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, UK
| | - Xuenong Bo
- Center for Neuroscience, Surgery and Trauma, Queen Mary University of London, London, UK
| | - Derryck Shewan
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, UK
| | - Wenlong Huang
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, UK
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Silva D, Sousa R, Salgado A. Hydrogels as delivery systems for spinal cord injury regeneration. Mater Today Bio 2021; 9:100093. [PMID: 33665602 PMCID: PMC7905359 DOI: 10.1016/j.mtbio.2021.100093] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 01/04/2023] Open
Abstract
Spinal cord injury is extremely debilitating, both at physiological and psychological levels, changing completely the patient's lifestyle. The introduction of biomaterials has opened a new window to develop a therapeutic approach to induce regeneration after injury due to similarities with extracellular matrix. Particularly, hydrogels have the ability to support axonal growth and endogenous regeneration. Moreover, they can also act as potential matrixes in which to load and deliver therapeutic agents at injury site. In this review, we highlight some important characteristics to be considered when designing hydrogels as delivery systems (DS), such as rheology, mesh size, swelling, degradation, gelation temperature and surface charge. Additionally, affinity-based release systems, incorporation of nanoparticles, or ion-mediated interactions are also pondered. Overall, hydrogel DS aim to promote a sustained, controlled and prolonged release at injury site, allowing a targeted oriented action of the therapeutic agent that will be used.
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Affiliation(s)
- D. Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
- ICVS/3B's—PT Government Associate Laboratory, 4710-057/4805-017, Braga/Guimarães, Portugal
- Stemmatters, Biotecnologia e Medicina Regenerativa SA, 4805-017, Guimarães, Portugal
| | - R.A. Sousa
- Stemmatters, Biotecnologia e Medicina Regenerativa SA, 4805-017, Guimarães, Portugal
| | - A.J. Salgado
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
- ICVS/3B's—PT Government Associate Laboratory, 4710-057/4805-017, Braga/Guimarães, Portugal
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13
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Omelchenko A, Singh NK, Firestein BL. Current advances in in vitro models of central nervous system trauma. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2020; 14:34-41. [PMID: 32671312 PMCID: PMC7363028 DOI: 10.1016/j.cobme.2020.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
CNS trauma is a prominent cause of mortality and morbidity, and although much effort has focused on developing treatments for CNS trauma-related pathologies, little progress has been made. Pre-clinical models of TBI and SCI suffer from significant drawbacks, which result in substantial failures during clinical translation of promising pre-clinical therapies. Here, we review recent advances made in the development of in vitro models of CNS trauma, the promises and drawbacks of current in vitro CNS injury models, and the attributes necessary for future models to accurately mimic the trauma microenvironment and facilitate CNS trauma drug discovery. The goal is to provide insight for the development of future CNS injury models and to aid researchers in selecting effective models for pre-clinical research of trauma therapeutics.
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Affiliation(s)
- Anton Omelchenko
- Department of Cell Biology and Neuroscience; Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ 08854-8082
- Neuroscience Graduate Program, Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ 08854-8082
| | - Nisha K. Singh
- Department of Cell Biology and Neuroscience; Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ 08854-8082
- Molecular Biosciences Graduate Program, Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ 08854-8082
| | - Bonnie L. Firestein
- Department of Cell Biology and Neuroscience; Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ 08854-8082
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14
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Yang T, Dai Y, Chen G, Cui S. Dissecting the Dual Role of the Glial Scar and Scar-Forming Astrocytes in Spinal Cord Injury. Front Cell Neurosci 2020; 14:78. [PMID: 32317938 PMCID: PMC7147295 DOI: 10.3389/fncel.2020.00078] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 03/18/2020] [Indexed: 12/19/2022] Open
Abstract
Recovery from spinal cord injury (SCI) remains an unsolved problem. As a major component of the SCI lesion, the glial scar is primarily composed of scar-forming astrocytes and plays a crucial role in spinal cord regeneration. In recent years, it has become increasingly accepted that the glial scar plays a dual role in SCI recovery. However, the underlying mechanisms of this dual role are complex and need further clarification. This dual role also makes it difficult to manipulate the glial scar for therapeutic purposes. Here, we briefly discuss glial scar formation and some representative components associated with scar-forming astrocytes. Then, we analyze the dual role of the glial scar in a dynamic perspective with special attention to scar-forming astrocytes to explore the underlying mechanisms of this dual role. Finally, taking the dual role of the glial scar into account, we provide several pieces of advice on novel therapeutic strategies targeting the glial scar and scar-forming astrocytes.
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Affiliation(s)
- Tuo Yang
- Department of Hand Surgery, China-Japan Union Hospital of Jilin University, Changchun, China.,Medical School of Nantong University, Nantong, China
| | - YuJuan Dai
- Medical School of Nantong University, Nantong, China
| | - Gang Chen
- Department of Tissue and Embryology, Medical School of Nantong University, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, China
| | - ShuSen Cui
- Department of Hand Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
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15
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Epac2 Promotes Axonal Outgrowth and Attenuates the Glial Reaction in an Ex Vivo Model of Spinal Cord Injury. J Neurosci 2020; 40:2184-2185. [PMID: 32161180 DOI: 10.1523/jneurosci.2450-19.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/17/2020] [Accepted: 01/21/2020] [Indexed: 01/25/2023] Open
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