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McCoy HM, Polcyn R, Banik NL, Haque A. Regulation of enolase activation to promote neural protection and regeneration in spinal cord injury. Neural Regen Res 2023; 18:1457-1462. [PMID: 36571342 PMCID: PMC10075133 DOI: 10.4103/1673-5374.361539] [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: 08/10/2022] [Revised: 10/10/2022] [Accepted: 10/26/2022] [Indexed: 11/19/2022] Open
Abstract
Spinal cord injury (SCI) is a debilitating condition characterized by damage to the spinal cord resulting in loss of function, mobility, and sensation with no U.S. Food and Drug Administration-approved cure. Enolase, a multifunctional glycolytic enzyme upregulated after SCI, promotes pro- and anti-inflammatory events and regulates functional recovery in SCI. Enolase is normally expressed in the cytosol, but the expression is upregulated at the cell surface following cellular injury, promoting glial cell activation and signal transduction pathway activation. SCI-induced microglia activation triggers pro-inflammatory mediators at the injury site, activating other immune cells and metabolic events, i.e., Rho-associated kinase, contributing to the neuroinflammation found in SCI. Enolase surface expression also activates cathepsin X, resulting in cleavage of the C-terminal end of neuron-specific enolase (NSE) and non-neuronal enolase (NNE). Fully functional enolase is necessary as NSE/NNE C-terminal proteins activate many neurotrophic processes, i.e., the plasminogen activation system, phosphatidylinositol-4,5-bisphosphate 3-kinase/protein kinase B, and mitogen-activated protein kinase/extracellular signal-regulated kinase. Studies here suggest an enolase inhibitor, ENOblock, attenuates the activation of Rho-associated kinase, which may decrease glial cell activation and promote functional recovery following SCI. Also, ENOblock inhibits cathepsin X, which may help prevent the cleavage of the neurotrophic C-terminal protein allowing full plasminogen activation and phosphatidylinositol-4,5-bisphosphate 3-kinase/mitogen-activated protein kinase activity. The combined NSE/cathepsin X inhibition may serve as a potential therapeutic strategy for preventing neuroinflammation/degeneration and promoting neural cell regeneration and recovery following SCI. The role of cell membrane-expressed enolase and associated metabolic events should be investigated to determine if the same strategies can be applied to other neurodegenerative diseases. Hence, this review discusses the importance of enolase activation and inhibition as a potential therapeutic target following SCI to promote neuronal survival and regeneration.
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Affiliation(s)
- Hannah M. McCoy
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA
| | - Rachel Polcyn
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA
| | - Naren L. Banik
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA
- Department of Neurosurgery, Medical University of South Carolina, Charleston, SC, USA
- Ralph H. Johnson Veterans Administration Medical Center, Charleston, SC, USA
| | - Azizul Haque
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA
- Department of Neurosurgery, Medical University of South Carolina, Charleston, SC, USA
- Ralph H. Johnson Veterans Administration Medical Center, Charleston, SC, USA
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Shams R, Banik NL, Haque A. Implications of enolase in the RANKL-mediated osteoclast activity following spinal cord injury. ACTA ACUST UNITED AC 2021; 45:1453-1457. [PMID: 34539043 PMCID: PMC8445338 DOI: 10.32604/biocell.2021.017659] [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] [Indexed: 11/15/2022]
Abstract
Spinal Cord Injury (SCI) is a debilitating condition characterized by damage to the spinal cord, resulting in loss of function, mobility, and sensation. Although increasingly prevalent in the US, no FDA-approved therapy exists due to the unfortunate complexity of the condition, and the difficulties of SCI may be furthered by the development of SCI-related complications, such as osteoporosis. SCI demonstrates two crucial stages for consideration: the primary stage and the secondary stage. While the primary stage is suggested to be immediate and irreversible, the secondary stage is proposed as a promising window of opportunity for therapeutic intervention. Enolase, a metabolic enzyme upregulated after SCI, performs non-glycolytic functions, promoting inflammatory events via extracellular degradative actions and increased production of inflammatory cytokines and chemokines. Neuron-specific enolase (NSE) serves as a biomarker of functional damage to neurons following SCI, and the inhibition of NSE has been demonstrated to reduce signs of secondary injury of SCI and to ameliorate dysfunction. This Viewpoint article involves enolase activation in the regulation of RANK-RANKL pathway and summarizes succinctly the mechanisms influencing osteoclast-mediated resorption of bone in SCI. Our laboratory proposes that inhibition of enolase activation may reduce SCI-induced inflammatory response and decrease osteoclast activity, limiting the chances of skeletal tissue loss in SCI.
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Affiliation(s)
- Ramsha Shams
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29425, USA.,Department of Neurosurgery, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Naren L Banik
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29425, USA.,Department of Neurosurgery, Medical University of South Carolina, Charleston, SC 29425, USA.,Ralph H. Johnson Veterans Administration Medical Center, Charleston, SC 29401, USA
| | - Azizul Haque
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29425, USA
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Traumatic brain injury biomarkers in pediatric patients: a systematic review. Neurosurg Rev 2021; 45:167-197. [PMID: 34170424 DOI: 10.1007/s10143-021-01588-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 05/23/2021] [Accepted: 06/15/2021] [Indexed: 10/21/2022]
Abstract
Traumatic brain injury (TBI) is the main cause of pediatric trauma death and disability worldwide. Recent studies have sought to identify biomarkers of TBI for the purpose of assessing functional outcomes. The aim of this systematic review was to evaluate the utility of TBI biomarkers in the pediatric population by summarizing recent findings in the medical literature. A total of 303 articles were retrieved from our search. An initial screening to remove duplicate studies yielded 162 articles. After excluding all articles that did not meet the inclusion criteria, 56 studies were gathered. Among the 56 studies, 36 analyzed serum biomarkers; 11, neuroimaging biomarkers; and 9, cerebrospinal fluid (CSF) biomarkers. Most studies assessed biomarkers in the serum, reflecting the feasibility of obtaining blood samples compared to obtaining CSF or performing neuroimaging. S100B was the most studied serum biomarker in TBI, followed by SNE and UCH-L1, whereas in CSF analysis, there was no unanimity. Among the different neuroimaging techniques employed, diffusion tensor imaging (DTI) was the most common, seemingly holding diagnostic power in the pediatric TBI clinical setting. The number of cross-sectional studies was similar to the number of longitudinal studies. Our data suggest that S100B measurement has high sensitivity and great promise in diagnosing pediatric TBI, ideally when associated with head CT examination and clinical decision protocols. Further large-scale longitudinal studies addressing TBI biomarkers in children are required to establish more accurate diagnostic protocols and prognostic tools.
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Multifunctional neuron-specific enolase: its role in lung diseases. Biosci Rep 2020; 39:220911. [PMID: 31642468 PMCID: PMC6859115 DOI: 10.1042/bsr20192732] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 10/22/2019] [Accepted: 10/22/2019] [Indexed: 12/13/2022] Open
Abstract
Neuron-specific enolase (NSE), also known as gamma (γ) enolase or enolase-2 (Eno2), is a form of glycolytic enolase isozyme and is considered a multifunctional protein. NSE is mainly expressed in the cytoplasm of neurons and neuroendocrine cells, especially in those of the amine precursor uptake and decarboxylation (APUD) lineage such as pituitary, thyroid, pancreas, intestine and lung. In addition to its well-established glycolysis function in the cytoplasm, changes in cell localization and differential expression of NSE are also associated with several pathologies such as infection, inflammation, autoimmune diseases and cancer. This article mainly discusses the role and diagnostic potential of NSE in some lung diseases.
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Polcyn R, Capone M, Matzelle D, Hossain A, Chandran R, Banik NL, Haque A. Enolase inhibition alters metabolic hormones and inflammatory factors to promote neuroprotection in spinal cord injury. Neurochem Int 2020; 139:104788. [PMID: 32650031 DOI: 10.1016/j.neuint.2020.104788] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/10/2020] [Accepted: 06/20/2020] [Indexed: 12/17/2022]
Abstract
Enolase inhibition is a potential therapeutic strategy currently being investigated for treatment of spinal cord injury (SCI) as it reduces pro-inflammatory cytokines and chemokines, alters metabolic factors, and reduces gliosis in acute SCI. Herein, the role of enolase in SCI has been examined to better understand the effects of this enzyme on inflammation, metabolic hormones, glial cell activation, and neuroprotection under these shorter injury conditions. Immunohistochemical analyses of inflammatory markers vimentin, Cox-2, and caspase-1 indicated that enolase inhibition attenuated the elevated levels of inflammation seen following SCI. Iba1, GFAP, NFP, and CSPG staining indicated that enolase inhibition with prolonged administration of ENOblock reduced microglia/astrocyte activation and lead to enhanced neuroprotection in SCI. An analysis of metabolic hormones revealed that ENOblock treatment significantly upregulated plasma concentrations of peptide YY, glucagon-like peptide 1, glucose-dependent insulinotropic peptide, glucagon, and insulin hormones as compared to vehicle-treated controls (Mann-Whitney, p ≤ 0.05). ENOblock did not have a significant effect on plasma concentrations of pancreatic polypeptide. Interestingly, ENOblock treatment inhibited chondroitin sulfate proteoglycan (CSPG), which is produced by activated glia and serves to block regrowth of axons across the lesion site following injury. An increased level of NeuN and MBP with reduced caspase-1 was detected in SCI tissues after ENOblock treatment, suggesting preservation of myelin and induction of neuroprotection. ENOblock also induced improved motor function in SCI rats, indicating a role for enolase in modulating inflammatory and metabolic factors in SCI with important implications for clinical consideration.
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Affiliation(s)
- Rachel Polcyn
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA
| | - Mollie Capone
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA; Department of Neurosurgery, Medical University of South Carolina, 96 Jonathan Lucas Street Charleston, SC 29425, USA
| | - Denise Matzelle
- Department of Neurosurgery, Medical University of South Carolina, 96 Jonathan Lucas Street Charleston, SC 29425, USA; Ralph H. Johnson Veterans Administration Medical Center, 109 Bee St, Charleston, SC 29401, USA
| | - Azim Hossain
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA
| | - Raghavendar Chandran
- Department of Neurosurgery, Medical University of South Carolina, 96 Jonathan Lucas Street Charleston, SC 29425, USA
| | - Naren L Banik
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA; Department of Neurosurgery, Medical University of South Carolina, 96 Jonathan Lucas Street Charleston, SC 29425, USA; Ralph H. Johnson Veterans Administration Medical Center, 109 Bee St, Charleston, SC 29401, USA
| | - Azizul Haque
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA.
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Haque A, Polcyn R, Matzelle D, Banik NL. New Insights into the Role of Neuron-Specific Enolase in Neuro-Inflammation, Neurodegeneration, and Neuroprotection. Brain Sci 2018; 8:E33. [PMID: 29463007 PMCID: PMC5836052 DOI: 10.3390/brainsci8020033] [Citation(s) in RCA: 128] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 02/12/2018] [Accepted: 02/13/2018] [Indexed: 01/18/2023] Open
Abstract
Neurodegeneration is a complex process that leads to irreversible neuronal damage and death in spinal cord injury (SCI) and various neurodegenerative diseases, which are serious, debilitating conditions. Despite exhaustive research, the cause of neuronal damage in these degenerative disorders is not completely understood. Elevation of cell surface α-enolase activates various inflammatory pathways, including the production of pro-inflammatory cytokines, chemokines, and some growth factors that are detrimental to neuronal cells. While α-enolase is present in all neurological tissues, it can also be converted to neuron specific enolase (NSE). NSE is a glycolytic enzyme found in neuronal and neuroendocrine tissues that may play a dual role in promoting both neuroinflammation and neuroprotection in SCI and other neurodegenerative events. Elevated NSE can promote ECM degradation, inflammatory glial cell proliferation, and actin remodeling, thereby affecting migration of activated macrophages and microglia to the injury site and promoting neuronal cell death. Thus, NSE could be a reliable, quantitative, and specific marker of neuronal injury. Depending on the injury, disease, and microenvironment, NSE may also show neurotrophic function as it controls neuronal survival, differentiation, and neurite regeneration via activation of phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways. This review discusses possible implications of NSE expression and activity in neuroinflammation, neurodegeneration, and neuroprotection in SCI and various neurodegenerative diseases for prognostic and therapeutic potential.
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Affiliation(s)
- Azizul Haque
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29401, USA.
| | - Rachel Polcyn
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29401, USA.
| | - Denise Matzelle
- Department of Neurosurgery, Medical University of South Carolina, Charleston, SC 29401, USA.
- Ralph H. Johnson Veterans Administration Medical Center, Charleston, SC 29401, USA.
| | - Naren L Banik
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29401, USA.
- Department of Neurosurgery, Medical University of South Carolina, Charleston, SC 29401, USA.
- Ralph H. Johnson Veterans Administration Medical Center, Charleston, SC 29401, USA.
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