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Liao S, Chen Y, Luo Y, Zhang M, Min J. The phenotypic changes of Schwann cells promote the functional repair of nerve injury. Neuropeptides 2024; 106:102438. [PMID: 38749170 DOI: 10.1016/j.npep.2024.102438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 05/08/2024] [Accepted: 05/09/2024] [Indexed: 06/17/2024]
Abstract
Functional recovery after nerve injury is a significant challenge due to the complex nature of nerve injury repair and the non-regeneration of neurons. Schwann cells (SCs), play a crucial role in the nerve injury repair process because of their high plasticity, secretion, and migration abilities. Upon nerve injury, SCs undergo a phenotypic change and redifferentiate into a repair phenotype, which helps in healing by recruiting phagocytes, removing myelin fragments, promoting axon regeneration, and facilitating myelin formation. However, the repair phenotype can be unstable, limiting the effectiveness of the repair. Recent research has found that transplantation of SCs can be an effective treatment option, therefore, it is essential to comprehend the phenotypic changes of SCs and clarify the related mechanisms to develop the transplantation therapy further.
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Affiliation(s)
- Shufen Liao
- The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, China
| | - Yan Chen
- The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, China
| | - Yin Luo
- The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, China
| | - Mengqi Zhang
- The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, China
| | - Jun Min
- Neurology Department, The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, China.
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Su Y, Huang M, Thomas AG, Maragakis J, Huizar KDJ, Zheng Y, Wu Y, Farah MH, Slusher BS. GCPII Inhibition Promotes Remyelination after Peripheral Nerve Injury in Aged Mice. Int J Mol Sci 2024; 25:6893. [PMID: 39000003 PMCID: PMC11241013 DOI: 10.3390/ijms25136893] [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: 06/07/2024] [Revised: 06/18/2024] [Accepted: 06/21/2024] [Indexed: 07/14/2024] Open
Abstract
Peripheral nerve injuries (PNIs) represent a significant clinical challenge, particularly in elderly populations where axonal remyelination and regeneration are impaired. Developing therapies to enhance these processes is crucial for improving PNI repair outcomes. Glutamate carboxypeptidase II (GCPII) is a neuropeptidase that plays a pivotal role in modulating glutamate signaling through its enzymatic cleavage of the abundant neuropeptide N-acetyl aspartyl glutamate (NAAG) to liberate glutamate. Within the PNS, GCPII is expressed in Schwann cells and activated macrophages, and its expression is amplified with aging. In this study, we explored the therapeutic potential of inhibiting GCPII activity following PNI. We report significant GCPII protein and activity upregulation following PNI, which was normalized by the potent and selective GCPII inhibitor 2-(phosphonomethyl)-pentanedioic acid (2-PMPA). In vitro, 2-PMPA robustly enhanced myelination in dorsal root ganglion (DRG) explants. In vivo, using a sciatic nerve crush injury model in aged mice, 2-PMPA accelerated remyelination, as evidenced by increased myelin sheath thickness and higher numbers of remyelinated axons. These findings suggest that GCPII inhibition may be a promising therapeutic strategy to enhance remyelination and potentially improve functional recovery after PNI, which is especially relevant in elderly PNI patients where this process is compromised.
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Affiliation(s)
- Yu Su
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (Y.S.); (M.H.); (A.G.T.); (J.M.); (K.D.J.H.); (Y.Z.); (Y.W.)
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Meixiang Huang
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (Y.S.); (M.H.); (A.G.T.); (J.M.); (K.D.J.H.); (Y.Z.); (Y.W.)
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ajit G. Thomas
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (Y.S.); (M.H.); (A.G.T.); (J.M.); (K.D.J.H.); (Y.Z.); (Y.W.)
| | - John Maragakis
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (Y.S.); (M.H.); (A.G.T.); (J.M.); (K.D.J.H.); (Y.Z.); (Y.W.)
| | - Kaitlyn D. J. Huizar
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (Y.S.); (M.H.); (A.G.T.); (J.M.); (K.D.J.H.); (Y.Z.); (Y.W.)
| | - Yuxin Zheng
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (Y.S.); (M.H.); (A.G.T.); (J.M.); (K.D.J.H.); (Y.Z.); (Y.W.)
| | - Ying Wu
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (Y.S.); (M.H.); (A.G.T.); (J.M.); (K.D.J.H.); (Y.Z.); (Y.W.)
| | - Mohamed H. Farah
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Barbara S. Slusher
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (Y.S.); (M.H.); (A.G.T.); (J.M.); (K.D.J.H.); (Y.Z.); (Y.W.)
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Psychiatry and Behavioral Science, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Maitre M, Jeltsch-David H, Okechukwu NG, Klein C, Patte-Mensah C, Mensah-Nyagan AG. Myelin in Alzheimer's disease: culprit or bystander? Acta Neuropathol Commun 2023; 11:56. [PMID: 37004127 PMCID: PMC10067200 DOI: 10.1186/s40478-023-01554-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 03/20/2023] [Indexed: 04/03/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder with neuronal and synaptic losses due to the accumulation of toxic amyloid β (Αβ) peptide oligomers, plaques, and tangles containing tau (tubulin-associated unit) protein. While familial AD is caused by specific mutations, the sporadic disease is more common and appears to result from a complex chronic brain neuroinflammation with mitochondriopathies, inducing free radicals' accumulation. In aged brain, mutations in DNA and several unfolded proteins participate in a chronic amyloidosis response with a toxic effect on myelin sheath and axons, leading to cognitive deficits and dementia. Αβ peptides are the most frequent form of toxic amyloid oligomers. Accumulations of misfolded proteins during several years alters different metabolic mechanisms, induce chronic inflammatory and immune responses with toxic consequences on neuronal cells. Myelin composition and architecture may appear to be an early target for the toxic activity of Aβ peptides and others hydrophobic misfolded proteins. In this work, we describe the possible role of early myelin alterations in the genesis of neuronal alterations and the onset of symptomatology. We propose that some pathophysiological and clinical forms of the disease may arise from structural and metabolic disorders in the processes of myelination/demyelination of brain regions where the accumulation of non-functional toxic proteins is important. In these forms, the primacy of the deleterious role of amyloid peptides would be a matter of questioning and the initiating role of neuropathology would be primarily the fact of dysmyelination.
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Affiliation(s)
- Michel Maitre
- Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques, Fédération de Médecine Translationnelle de Strasbourg (FMTS), INSERM U1119, Université de Strasbourg, Bâtiment CRBS de la Faculté de Médecine, 1 rue Eugène Boeckel, Strasbourg, 67000, France.
| | - Hélène Jeltsch-David
- Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques, Fédération de Médecine Translationnelle de Strasbourg (FMTS), INSERM U1119, Université de Strasbourg, Bâtiment CRBS de la Faculté de Médecine, 1 rue Eugène Boeckel, Strasbourg, 67000, France
- Biotechnologie et signalisation cellulaire, UMR 7242 CNRS, Université de Strasbourg, 300 Boulevard Sébastien Brant CS 10413, Illkirch cedex, 67412, France
| | - Nwife Getrude Okechukwu
- Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques, Fédération de Médecine Translationnelle de Strasbourg (FMTS), INSERM U1119, Université de Strasbourg, Bâtiment CRBS de la Faculté de Médecine, 1 rue Eugène Boeckel, Strasbourg, 67000, France
| | - Christian Klein
- Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques, Fédération de Médecine Translationnelle de Strasbourg (FMTS), INSERM U1119, Université de Strasbourg, Bâtiment CRBS de la Faculté de Médecine, 1 rue Eugène Boeckel, Strasbourg, 67000, France
| | - Christine Patte-Mensah
- Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques, Fédération de Médecine Translationnelle de Strasbourg (FMTS), INSERM U1119, Université de Strasbourg, Bâtiment CRBS de la Faculté de Médecine, 1 rue Eugène Boeckel, Strasbourg, 67000, France
| | - Ayikoe-Guy Mensah-Nyagan
- Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques, Fédération de Médecine Translationnelle de Strasbourg (FMTS), INSERM U1119, Université de Strasbourg, Bâtiment CRBS de la Faculté de Médecine, 1 rue Eugène Boeckel, Strasbourg, 67000, France
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Yuan Y, Wang Y, Wu S, Zhao MY. Review: Myelin clearance is critical for regeneration after peripheral nerve injury. Front Neurol 2022; 13:908148. [PMID: 36588879 PMCID: PMC9801717 DOI: 10.3389/fneur.2022.908148] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 11/17/2022] [Indexed: 12/23/2022] Open
Abstract
Traumatic peripheral nerve injury occurs frequently and is a major clinical and public health problem that can lead to functional impairment and permanent disability. Despite the availability of modern diagnostic procedures and advanced microsurgical techniques, active recovery after peripheral nerve repair is often unsatisfactory. Peripheral nerve regeneration involves several critical events, including the recreation of the microenvironment and remyelination. Results from previous studies suggest that the peripheral nervous system (PNS) has a greater capacity for repair than the central nervous system. Thus, it will be important to understand myelin and myelination specifically in the PNS. This review provides an update on myelin biology and myelination in the PNS and discusses the mechanisms that promote myelin clearance after injury. The roles of Schwann cells and macrophages are considered at length, together with the possibility of exogenous intervention.
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Affiliation(s)
- YiMing Yuan
- Laboratory of Brain Function and Neurorehabilitation, Heilongjiang University of Chinese Medicine, Harbin, China
| | - Yan Wang
- Laboratory of Brain Function and Neurorehabilitation, Heilongjiang University of Chinese Medicine, Harbin, China,Department of Rehabilitation, The Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, China,*Correspondence: Yan Wang
| | - ShanHong Wu
- Laboratory of Brain Function and Neurorehabilitation, Heilongjiang University of Chinese Medicine, Harbin, China
| | - Ming Yue Zhao
- Laboratory of Brain Function and Neurorehabilitation, Heilongjiang University of Chinese Medicine, Harbin, China,Department of Rehabilitation, The Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, China
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5
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Axonal Regeneration: Underlying Molecular Mechanisms and Potential Therapeutic Targets. Biomedicines 2022; 10:biomedicines10123186. [PMID: 36551942 PMCID: PMC9775075 DOI: 10.3390/biomedicines10123186] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/21/2022] [Accepted: 12/01/2022] [Indexed: 12/13/2022] Open
Abstract
Axons in the peripheral nervous system have the ability to repair themselves after damage, whereas axons in the central nervous system are unable to do so. A common and important characteristic of damage to the spinal cord, brain, and peripheral nerves is the disruption of axonal regrowth. Interestingly, intrinsic growth factors play a significant role in the axonal regeneration of injured nerves. Various factors such as proteomic profile, microtubule stability, ribosomal location, and signalling pathways mark a line between the central and peripheral axons' capacity for self-renewal. Unfortunately, glial scar development, myelin-associated inhibitor molecules, lack of neurotrophic factors, and inflammatory reactions are among the factors that restrict axonal regeneration. Molecular pathways such as cAMP, MAPK, JAK/STAT, ATF3/CREB, BMP/SMAD, AKT/mTORC1/p70S6K, PI3K/AKT, GSK-3β/CLASP, BDNF/Trk, Ras/ERK, integrin/FAK, RhoA/ROCK/LIMK, and POSTN/integrin are activated after nerve injury and are considered significant players in axonal regeneration. In addition to the aforementioned pathways, growth factors, microRNAs, and astrocytes are also commendable participants in regeneration. In this review, we discuss the detailed mechanism of each pathway along with key players that can be potentially valuable targets to help achieve quick axonal healing. We also identify the prospective targets that could help close knowledge gaps in the molecular pathways underlying regeneration and shed light on the creation of more powerful strategies to encourage axonal regeneration after nervous system injury.
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6
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Basu S, Choudhury IN, Lee JYP, Chacko A, Ekberg JAK, St John JA. Macrophages Treated with VEGF and PDGF Exert Paracrine Effects on Olfactory Ensheathing Cell Function. Cells 2022; 11:cells11152408. [PMID: 35954252 PMCID: PMC9368560 DOI: 10.3390/cells11152408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/29/2022] [Accepted: 08/01/2022] [Indexed: 02/05/2023] Open
Abstract
Glial cell transplantation using olfactory ensheathing cells (OECs) holds a promising approach for treating spinal cord injury (SCI). However, integration of OECs into the hostile acute secondary injury site requires interaction and response to macrophages. Immunomodulation of macrophages to reduce their impact on OECs may improve the functionality of OECs. Vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF), known for their immunomodulatory and neuroprotective functions, have provided improved outcomes in SCI animal models. Thus, VEGF and PDGF modulation of the SCI microenvironment may be beneficial for OEC transplantation. In this in vitro study, the effect of VEGF and PDGF on macrophages in an inflammatory condition was tested. Combined VEGF + PDGF reduced translocation nuclear factor kappa B p65 in macrophages without altering pro-inflammatory cytokines. Further, the ability of OECs to phagocytose myelin debris was assessed using macrophage-conditioned medium. Conditioned medium from macrophages incubated with PDGF and combined VEGF + PDGF in inflammatory conditions promoted phagocytosis by OECs. The growth factor treated conditioned media also modulated the expression of genes associated with nerve repair and myelin expression in OECs. Overall, these results suggest that the use of growth factors together with OEC transplantation may be beneficial in SCI therapy.
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Affiliation(s)
- Souptik Basu
- Clem Jones Centre for Neurobiology and Stem Cell Research, Nathan Campus, Griffith University, Nathan, QLD 4222, Australia
- Menzies Health Institute Queensland, Southport Campus, Griffith University, Southport, QLD 4222, Australia
| | - Indra N. Choudhury
- Clem Jones Centre for Neurobiology and Stem Cell Research, Nathan Campus, Griffith University, Nathan, QLD 4222, Australia
- Menzies Health Institute Queensland, Southport Campus, Griffith University, Southport, QLD 4222, Australia
| | - Jia Yu Peppermint Lee
- Clem Jones Centre for Neurobiology and Stem Cell Research, Nathan Campus, Griffith University, Nathan, QLD 4222, Australia
| | - Anu Chacko
- Clem Jones Centre for Neurobiology and Stem Cell Research, Nathan Campus, Griffith University, Nathan, QLD 4222, Australia
- Menzies Health Institute Queensland, Southport Campus, Griffith University, Southport, QLD 4222, Australia
| | - Jenny A. K. Ekberg
- Clem Jones Centre for Neurobiology and Stem Cell Research, Nathan Campus, Griffith University, Nathan, QLD 4222, Australia
- Menzies Health Institute Queensland, Southport Campus, Griffith University, Southport, QLD 4222, Australia
- Griffith Institute for Drug Discovery, Nathan Campus, Griffith University, Nathan, QLD 4111, Australia
| | - James A. St John
- Clem Jones Centre for Neurobiology and Stem Cell Research, Nathan Campus, Griffith University, Nathan, QLD 4222, Australia
- Menzies Health Institute Queensland, Southport Campus, Griffith University, Southport, QLD 4222, Australia
- Griffith Institute for Drug Discovery, Nathan Campus, Griffith University, Nathan, QLD 4111, Australia
- Correspondence:
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7
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Taylor HA, Przemylska L, Clavane EM, Meakin PJ. BACE1: More than just a β-secretase. Obes Rev 2022; 23:e13430. [PMID: 35119166 PMCID: PMC9286785 DOI: 10.1111/obr.13430] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/04/2022] [Accepted: 01/16/2022] [Indexed: 02/06/2023]
Abstract
β-site amyloid precursor protein cleaving enzyme-1 (BACE1) research has historically focused on its actions as the β-secretase responsible for the production of β-amyloid beta, observed in Alzheimer's disease. Although the greatest expression of BACE1 is found in the brain, BACE1 mRNA and protein is also found in many cell types including pancreatic β-cells, adipocytes, hepatocytes, and vascular cells. Pathologically elevated BACE1 expression in these cells has been implicated in the development of metabolic diseases, including type 2 diabetes, obesity, and cardiovascular disease. In this review, we examine key questions surrounding the BACE1 literature, including how is BACE1 regulated and how dysregulation may occur in disease, and understand how BACE1 regulates metabolism via cleavage of a myriad of substrates. The phenotype of the BACE1 knockout mice models, including reduced weight gain, increased energy expenditure, and enhanced leptin signaling, proposes a physiological role of BACE1 in regulating energy metabolism and homeostasis. Taken together with the weight loss observed with BACE1 inhibitors in clinical trials, these data highlight a novel role for BACE1 in regulation of metabolic physiology. Finally, this review aims to examine the possibility that BACE1 inhibitors could provide a innovative treatment for obesity and its comorbidities.
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Affiliation(s)
- Hannah A Taylor
- Discovery & Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
| | - Lena Przemylska
- Discovery & Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
| | - Eva M Clavane
- Discovery & Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
| | - Paul J Meakin
- Discovery & Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
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8
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Jeong H, Shin H, Hong S, Kim Y. Physiological Roles of Monomeric Amyloid-β and Implications for Alzheimer's Disease Therapeutics. Exp Neurobiol 2022; 31:65-88. [PMID: 35673997 PMCID: PMC9194638 DOI: 10.5607/en22004] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/26/2022] [Accepted: 03/30/2022] [Indexed: 12/23/2022] Open
Abstract
Alzheimer's disease (AD) progressively inflicts impairment of synaptic functions with notable deposition of amyloid-β (Aβ) as senile plaques within the extracellular space of the brain. Accordingly, therapeutic directions for AD have focused on clearing Aβ plaques or preventing amyloidogenesis based on the amyloid cascade hypothesis. However, the emerging evidence suggests that Aβ serves biological roles, which include suppressing microbial infections, regulating synaptic plasticity, promoting recovery after brain injury, sealing leaks in the blood-brain barrier, and possibly inhibiting the proliferation of cancer cells. More importantly, these functions were found in in vitro and in vivo investigations in a hormetic manner, that is to be neuroprotective at low concentrations and pathological at high concentrations. We herein summarize the physiological roles of monomeric Aβ and current Aβ-directed therapies in clinical trials. Based on the evidence, we propose that novel therapeutics targeting Aβ should selectively target Aβ in neurotoxic forms such as oligomers while retaining monomeric Aβ in order to preserve the physiological functions of Aβ monomers.
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Affiliation(s)
- Hyomin Jeong
- Division of Integrated Science and Engineering, Underwood International College, Yonsei University, Incheon 21983, Korea
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon 21983, Korea
- Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, Incheon 21983, Korea
| | - Heewon Shin
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon 21983, Korea
- Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, Incheon 21983, Korea
| | - Seungpyo Hong
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon 21983, Korea
- Yonsei Frontier Lab, Yonsei University, Seoul 03722, Korea
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA
- Wisconsin Center for NanoBioSystems, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - YoungSoo Kim
- Division of Integrated Science and Engineering, Underwood International College, Yonsei University, Incheon 21983, Korea
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon 21983, Korea
- Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, Incheon 21983, Korea
- Yonsei Frontier Lab, Yonsei University, Seoul 03722, Korea
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Juanez K, Ghose P. Repurposing the Killing Machine: Non-canonical Roles of the Cell Death Apparatus in Caenorhabditis elegans Neurons. Front Cell Dev Biol 2022; 10:825124. [PMID: 35237604 PMCID: PMC8882910 DOI: 10.3389/fcell.2022.825124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/31/2022] [Indexed: 12/29/2022] Open
Abstract
Here we highlight the increasingly divergent functions of the Caenorhabditis elegans cell elimination genes in the nervous system, beyond their well-documented roles in cell dismantling and removal. We describe relevant background on the C. elegans nervous system together with the apoptotic cell death and engulfment pathways, highlighting pioneering work in C. elegans. We discuss in detail the unexpected, atypical roles of cell elimination genes in various aspects of neuronal development, response and function. This includes the regulation of cell division, pruning, axon regeneration, and behavioral outputs. We share our outlook on expanding our thinking as to what cell elimination genes can do and noting their versatility. We speculate on the existence of novel genes downstream and upstream of the canonical cell death pathways relevant to neuronal biology. We also propose future directions emphasizing the exploration of the roles of cell death genes in pruning and guidance during embryonic development.
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10
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Pharmacological inhibition of BACE1 suppresses glioblastoma growth by stimulating macrophage phagocytosis of tumor cells. NATURE CANCER 2021; 2:1136-1151. [PMID: 35122055 PMCID: PMC8809483 DOI: 10.1038/s43018-021-00267-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 09/14/2021] [Indexed: 12/11/2022]
Abstract
Glioblastoma (GBM) contains abundant tumor-associated macrophages (TAMs). The majority of TAMs are tumor-promoting macrophages (pTAMs), while tumor-suppressive macrophages (sTAMs) are the minority. Thus, reprogramming pTAMs into sTAMs represents an attractive therapeutic strategy. By screening a collection of small-molecule compounds, we find that inhibiting β-site amyloid precursor protein-cleaving enzyme 1 (BACE1) with MK-8931 potently reprograms pTAMs into sTAMs and promotes macrophage phagocytosis of glioma cells; moreover, low-dose radiation markedly enhances TAM infiltration and synergizes with MK-8931 treatment to suppress malignant growth. BACE1 is preferentially expressed by pTAMs in human GBMs and is required to maintain pTAM polarization through trans-interleukin 6 (IL-6)-soluble IL-6 receptor (sIL-6R)-signal transducer and activator of transcription 3 (STAT3) signaling. Because MK-8931 and other BACE1 inhibitors have been developed for Alzheimer's disease and have been shown to be safe for humans in clinical trials, these inhibitors could potentially be streamlined for cancer therapy. Collectively, this study offers a promising therapeutic approach to enhance macrophage-based therapy for malignant tumors.
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11
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Aldskogius H, Kozlova EN. Dorsal Root Injury-A Model for Exploring Pathophysiology and Therapeutic Strategies in Spinal Cord Injury. Cells 2021; 10:2185. [PMID: 34571835 PMCID: PMC8470715 DOI: 10.3390/cells10092185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 12/12/2022] Open
Abstract
Unraveling the cellular and molecular mechanisms of spinal cord injury is fundamental for our possibility to develop successful therapeutic approaches. These approaches need to address the issues of the emergence of a non-permissive environment for axonal growth in the spinal cord, in combination with a failure of injured neurons to mount an effective regeneration program. Experimental in vivo models are of critical importance for exploring the potential clinical relevance of mechanistic findings and therapeutic innovations. However, the highly complex organization of the spinal cord, comprising multiple types of neurons, which form local neural networks, as well as short and long-ranging ascending or descending pathways, complicates detailed dissection of mechanistic processes, as well as identification/verification of therapeutic targets. Inducing different types of dorsal root injury at specific proximo-distal locations provide opportunities to distinguish key components underlying spinal cord regeneration failure. Crushing or cutting the dorsal root allows detailed analysis of the regeneration program of the sensory neurons, as well as of the glial response at the dorsal root-spinal cord interface without direct trauma to the spinal cord. At the same time, a lesion at this interface creates a localized injury of the spinal cord itself, but with an initial neuronal injury affecting only the axons of dorsal root ganglion neurons, and still a glial cell response closely resembling the one seen after direct spinal cord injury. In this review, we provide examples of previous research on dorsal root injury models and how these models can help future exploration of mechanisms and potential therapies for spinal cord injury repair.
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Affiliation(s)
- Håkan Aldskogius
- Laboratory of Regenertive Neurobiology, Biomedical Center, Department of Neuroscience, Uppsala University, 75124 Uppsala, Sweden;
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12
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Lomoio S, Willen R, Kim W, Ho KZ, Robinson EK, Prokopenko D, Kennedy ME, Tanzi RE, Tesco G. Gga3 deletion and a GGA3 rare variant associated with late onset Alzheimer's disease trigger BACE1 accumulation in axonal swellings. Sci Transl Med 2021; 12:12/570/eaba1871. [PMID: 33208500 DOI: 10.1126/scitranslmed.aba1871] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 05/18/2020] [Accepted: 08/03/2020] [Indexed: 12/13/2022]
Abstract
Axonal dystrophy, indicative of perturbed axonal transport, occurs early during Alzheimer's disease (AD) pathogenesis. Little is known about the mechanisms underlying this initial sign of the pathology. This study proves that Golgi-localized γ-ear-containing ARF binding protein 3 (GGA3) loss of function, due to Gga3 genetic deletion or a GGA3 rare variant that cosegregates with late-onset AD, disrupts the axonal trafficking of the β-site APP-cleaving enzyme 1 (BACE1) resulting in its accumulation in axonal swellings in cultured neurons and in vivo. We show that BACE pharmacological inhibition ameliorates BACE1 axonal trafficking and diminishes axonal dystrophies in Gga3 null neurons in vitro and in vivo. These data indicate that axonal accumulation of BACE1 engendered by GGA3 loss of function results in local toxicity leading to axonopathy. Gga3 deletion exacerbates axonal dystrophies in a mouse model of AD before β-amyloid (Aβ) deposition. Our study strongly supports a role for GGA3 in AD pathogenesis, where GGA3 loss of function triggers BACE1 axonal accumulation independently of extracellular Aβ, and initiates a cascade of events leading to the axonal damage distinctive of the early stage of AD.
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Affiliation(s)
- Selene Lomoio
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Rachel Willen
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
| | - WonHee Kim
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Kevin Z Ho
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Edward K Robinson
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Dmitry Prokopenko
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | | | - Rudolph E Tanzi
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Giuseppina Tesco
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA.
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13
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Fissel JA, Farah MH. The influence of BACE1 on macrophage recruitment and activity in the injured peripheral nerve. J Neuroinflammation 2021; 18:71. [PMID: 33722254 PMCID: PMC7962400 DOI: 10.1186/s12974-021-02121-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 02/26/2021] [Indexed: 01/13/2023] Open
Abstract
Following peripheral nerve injury, multiple cell types, including axons, Schwann cells, and macrophages, coordinate to promote nerve regeneration. However, this capacity for repair is limited, particularly in older populations, and current treatments are insufficient. A critical component of the regeneration response is the network of cell-to-cell signaling in the injured nerve microenvironment. Sheddases are expressed in the peripheral nerve and play a role in the regulation if this cell-to-cell signaling through cleavage of transmembrane proteins, enabling the regulation of multiple pathways through cis- and trans-cellular regulatory mechanisms. Enhanced axonal regeneration has been observed in mice with deletion of the sheddase beta-secretase (BACE1), a transmembrane aspartyl protease that has been studied in the context of Alzheimer’s disease. BACE1 knockout (KO) mice display enhanced macrophage recruitment and activity following nerve injury, although it is unclear whether this plays a role in driving the enhanced axonal regeneration. Further, it is unknown by what mechanism(s) BACE1 increases macrophage recruitment and activity. BACE1 has many substrates, several of which are known to have immunomodulatory activity. This review will discuss current knowledge of the role of BACE1 and other sheddases in peripheral nerve regeneration and outline known immunomodulatory BACE1 substrates and what potential roles they could play in peripheral nerve regeneration. Currently, the literature suggests that BACE1 and substrates that are expressed by neurons and Schwann cells are likely to be more important for this process than those expressed by macrophages. More broadly, BACE1 may play a role as an effector of immunomodulation beyond the peripheral nerve.
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Affiliation(s)
- John A Fissel
- Department of Neurology, Johns Hopkins University School of Medicine, The John G. Rangos Sr. Building, Room 239, 855 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Mohamed H Farah
- Department of Neurology, Johns Hopkins University School of Medicine, The John G. Rangos Sr. Building, Room 239, 855 N. Wolfe Street, Baltimore, MD, 21205, USA.
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14
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Asparagine Endopeptidase (δ Secretase), an Enzyme Implicated in Alzheimer's Disease Pathology, Is an Inhibitor of Axon Regeneration in Peripheral Nerves. eNeuro 2021; 8:ENEURO.0155-20.2020. [PMID: 33323399 PMCID: PMC7814480 DOI: 10.1523/eneuro.0155-20.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 11/20/2020] [Accepted: 11/23/2020] [Indexed: 01/11/2023] Open
Abstract
Asparagine endopeptidase (AEP) is a lysosomal protease implicated in the pathology of Alzheimer’s disease (AD). It is known to cleave the axonal microtubule associated protein, Tau, and amyloid precursor protein (APP), both of which might impede axon regeneration following peripheral nerve injury (PNI). Active AEP, AEP-cleaved fragments of Tau (Tau N368), and APP (APP N585) were found in injured peripheral nerves. In AEP null mice, elongation of regenerating axons after sciatic nerve transection and repair was increased relative to wild-type (WT) controls. Compound muscle action potentials (M responses) were restored in reinnervated muscles twice as fast after injury in AEP knock-out (KO) mice as WT controls. Neurite elongation in cultures of adult dorsal root ganglion (DRG) neurons derived from AEP KO mice was increased significantly relative to cultures from WT controls. In AEP KO mice exposed to 1 h of 20-Hz electrical stimulation (ES) at the time of nerve injury, no further enhancement of axon regeneration was observed. These findings support inhibition of AEP as a therapeutic target to enhance axon regeneration after PNI.
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15
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Marshall KL, Farah MH. Axonal regeneration and sprouting as a potential therapeutic target for nervous system disorders. Neural Regen Res 2021; 16:1901-1910. [PMID: 33642358 PMCID: PMC8343323 DOI: 10.4103/1673-5374.308077] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Nervous system disorders are prevalent health issues that will only continue to increase in frequency as the population ages. Dying-back axonopathy is a hallmark of many neurologic diseases and leads to axonal disconnection from their targets, which in turn leads to functional impairment. During the course of many of neurologic diseases, axons can regenerate or sprout in an attempt to reconnect with the target and restore synapse function. In amyotrophic lateral sclerosis (ALS), distal motor axons retract from neuromuscular junctions early in the disease-course before significant motor neuron death. There is evidence of compensatory motor axon sprouting and reinnervation of neuromuscular junctions in ALS that is usually quickly overtaken by the disease course. Potential drugs that enhance compensatory sprouting and encourage reinnervation may slow symptom progression and retain muscle function for a longer period of time in ALS and in other diseases that exhibit dying-back axonopathy. There remain many outstanding questions as to the impact of distinct disease-causing mutations on axonal outgrowth and regeneration, especially in regards to motor neurons derived from patient induced pluripotent stem cells. Compartmentalized microfluidic chambers are powerful tools for studying the distal axons of human induced pluripotent stem cells-derived motor neurons, and have recently been used to demonstrate striking regeneration defects in human motor neurons harboring ALS disease-causing mutations. Modeling the human neuromuscular circuit with human induced pluripotent stem cells-derived motor neurons will be critical for developing drugs that enhance axonal regeneration, sprouting, and reinnervation of neuromuscular junctions. In this review we will discuss compensatory axonal sprouting as a potential therapeutic target for ALS, and the use of compartmentalized microfluidic devices to find drugs that enhance regeneration and axonal sprouting of motor axons.
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Affiliation(s)
| | - Mohamed H Farah
- Department of Neurology at Johns Hopkins School of Medicine, Baltimore, MD, USA
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16
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Fissel JA, Farah MH. Macrophage-specific deletion of BACE1 does not enhance macrophage recruitment to the injured peripheral nerve. J Neuroimmunol 2020; 349:577423. [PMID: 33074142 DOI: 10.1016/j.jneuroim.2020.577423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/02/2020] [Accepted: 10/03/2020] [Indexed: 02/06/2023]
Abstract
Following peripheral nerve injury, macrophages are recruited to the injury site from circulation to clear cellular debris. Injured β-secretase 1 (BACE1) knockout mice have enhanced macrophage recruitment and debris clearance, which may be due to BACE1 activity in macrophages or the hypomyelination observed in BACE1 knockout mice. To assess if BACE1 expression by macrophages mediates enhanced macrophage recruitment we utilized mice with macrophage specific deletion of BACE1 and saw no increase in macrophage recruitment following injury. This study suggests that expression of BACE1 by macrophages may not be essential for increased recruitment observed previously in global BACE1 KO mice.
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Affiliation(s)
- John A Fissel
- Department of Neurology at Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mohamed H Farah
- Department of Neurology at Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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17
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Kent SA, Spires-Jones TL, Durrant CS. The physiological roles of tau and Aβ: implications for Alzheimer's disease pathology and therapeutics. Acta Neuropathol 2020; 140:417-447. [PMID: 32728795 PMCID: PMC7498448 DOI: 10.1007/s00401-020-02196-w] [Citation(s) in RCA: 197] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/20/2020] [Accepted: 07/20/2020] [Indexed: 01/18/2023]
Abstract
Tau and amyloid beta (Aβ) are the prime suspects for driving pathology in Alzheimer's disease (AD) and, as such, have become the focus of therapeutic development. Recent research, however, shows that these proteins have been highly conserved throughout evolution and may have crucial, physiological roles. Such functions may be lost during AD progression or be unintentionally disrupted by tau- or Aβ-targeting therapies. Tau has been revealed to be more than a simple stabiliser of microtubules, reported to play a role in a range of biological processes including myelination, glucose metabolism, axonal transport, microtubule dynamics, iron homeostasis, neurogenesis, motor function, learning and memory, neuronal excitability, and DNA protection. Aβ is similarly multifunctional, and is proposed to regulate learning and memory, angiogenesis, neurogenesis, repair leaks in the blood-brain barrier, promote recovery from injury, and act as an antimicrobial peptide and tumour suppressor. This review will discuss potential physiological roles of tau and Aβ, highlighting how changes to these functions may contribute to pathology, as well as the implications for therapeutic development. We propose that a balanced consideration of both the physiological and pathological roles of tau and Aβ will be essential for the design of safe and effective therapeutics.
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Affiliation(s)
- Sarah A. Kent
- Translational Neuroscience PhD Programme, Centre for Discovery Brain Sciences and the UK Dementia Research Institute, The University of Edinburgh, 1 George Square, Edinburgh, EH8 9JZ Scotland, UK
| | - Tara L. Spires-Jones
- Centre for Discovery Brain Sciences and the UK Dementia Research Institute, The University of Edinburgh, 1 George Square, Edinburgh, EH8 9JZ Scotland, UK
| | - Claire S. Durrant
- Centre for Discovery Brain Sciences and the UK Dementia Research Institute, The University of Edinburgh, 1 George Square, Edinburgh, EH8 9JZ Scotland, UK
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18
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Nocera G, Jacob C. Mechanisms of Schwann cell plasticity involved in peripheral nerve repair after injury. Cell Mol Life Sci 2020; 77:3977-3989. [PMID: 32277262 PMCID: PMC7532964 DOI: 10.1007/s00018-020-03516-9] [Citation(s) in RCA: 195] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 03/09/2020] [Accepted: 03/30/2020] [Indexed: 01/01/2023]
Abstract
The great plasticity of Schwann cells (SCs), the myelinating glia of the peripheral nervous system (PNS), is a critical feature in the context of peripheral nerve regeneration following traumatic injuries and peripheral neuropathies. After a nerve damage, SCs are rapidly activated by injury-induced signals and respond by entering the repair program. During the repair program, SCs undergo dynamic cell reprogramming and morphogenic changes aimed at promoting nerve regeneration and functional recovery. SCs convert into a repair phenotype, activate negative regulators of myelination and demyelinate the damaged nerve. Moreover, they express many genes typical of their immature state as well as numerous de-novo genes. These genes modulate and drive the regeneration process by promoting neuronal survival, damaged axon disintegration, myelin clearance, axonal regrowth and guidance to their former target, and by finally remyelinating the regenerated axon. Many signaling pathways, transcriptional regulators and epigenetic mechanisms regulate these events. In this review, we discuss the main steps of the repair program with a particular focus on the molecular mechanisms that regulate SC plasticity following peripheral nerve injury.
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Affiliation(s)
- Gianluigi Nocera
- Faculty of Biology, Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University, Mainz, Germany
| | - Claire Jacob
- Faculty of Biology, Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University, Mainz, Germany.
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19
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Stassart RM, Woodhoo A. Axo-glial interaction in the injured PNS. Dev Neurobiol 2020; 81:490-506. [PMID: 32628805 DOI: 10.1002/dneu.22771] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/28/2020] [Accepted: 06/12/2020] [Indexed: 12/11/2022]
Abstract
Axons share a close relationship with Schwann cells, their glial partners in peripheral nerves. An intricate axo-glia network of signals and bioactive molecules regulates the major aspects of nerve development and normal functioning of the peripheral nervous system. Disruptions to these complex axo-glial interactions can have serious neurological consequences, as typically seen in injured nerves. Recent studies in inherited neuropathies have demonstrated that damage to one of the partners in this symbiotic unit ultimately leads to impairment of the other partner, emphasizing the bidirectional influence of axon to glia and glia to axon signaling in these diseases. After physical trauma to nerves, dramatic alterations in the architecture and signaling environment of peripheral nerves take place. Here, axons and Schwann cells respond adaptively to these perturbations and change the nature of their reciprocal interactions, thereby driving the remodeling and regeneration of peripheral nerves. In this review, we focus on the nature and importance of axon-glia interactions in injured nerves, both for the reshaping and repair of nerves after trauma, and in driving pathology in inherited peripheral neuropathies.
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Affiliation(s)
- Ruth M Stassart
- Department of Neuropathology, University Clinic Leipzig, Leipzig, Germany
| | - Ashwin Woodhoo
- Nerve Disorders Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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20
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Baloh RH. The Nerve to Give BACE Inhibitors a Second Chance? Neurotherapeutics 2020; 17:966-967. [PMID: 32514890 PMCID: PMC7609629 DOI: 10.1007/s13311-020-00876-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Robert H Baloh
- Department of Neurology, Center for Neural Science and Medicine, Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA.
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21
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Tallon C, Marshall KL, Kennedy ME, Hyde LA, Farah MH. Pharmacological BACE Inhibition Improves Axonal Regeneration in Nerve Injury and Disease Models. Neurotherapeutics 2020; 17:973-988. [PMID: 32236823 PMCID: PMC7609814 DOI: 10.1007/s13311-020-00852-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
While the peripheral nervous system is able to repair itself following injury and disease, recovery is often slow and incomplete, with no available treatments to enhance the effectiveness of regeneration. Using knock-out and transgenic overexpressor mice, we previously reported that BACE1, an aspartyl protease, as reported by Hemming et al. (PLoS One 4:12, 2009), negatively regulates peripheral nerve regeneration. Here, we investigated whether pharmacological inhibition of BACE may enhance peripheral nerve repair following traumatic nerve injury or neurodegenerative disease. BACE inhibitor-treated mice had increased numbers of regenerating axons and enhanced functional recovery after a sciatic nerve crush while inhibition increased axonal sprouting following a partial nerve injury. In the SOD1G93A ALS mouse model, BACE inhibition increased axonal regeneration with improved muscle re-innervation. CHL1, a BACE1 substrate, was elevated in treated mice and may mediate enhanced regeneration. Our data demonstrates that pharmacological BACE inhibition accelerates peripheral axon regeneration after varied nerve injuries and could be used as a potential therapy.
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Affiliation(s)
- Carolyn Tallon
- Department of Neurology, Neuromuscular Division, Johns Hopkins University School of Medicine, The John G. Rangos Sr. Building, Room 239, 855 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Katherine L Marshall
- Department of Neurology, Neuromuscular Division, Johns Hopkins University School of Medicine, The John G. Rangos Sr. Building, Room 239, 855 N. Wolfe Street, Baltimore, MD, 21205, USA
| | | | | | - Mohamed H Farah
- Department of Neurology, Neuromuscular Division, Johns Hopkins University School of Medicine, The John G. Rangos Sr. Building, Room 239, 855 N. Wolfe Street, Baltimore, MD, 21205, USA.
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22
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Li C, Zhao B, Fan YN, Jia X, Liu Y. Expression of BACE1 in the Rat Carotid Body. Front Physiol 2020; 11:505. [PMID: 32508682 PMCID: PMC7251150 DOI: 10.3389/fphys.2020.00505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 04/24/2020] [Indexed: 11/13/2022] Open
Abstract
This study explored the expression of BACE1 (β-amyloid precursor protein cleaving enzyme 1) in the rat carotid body and the effect of CIH (cyclic intermittent hypoxia) on the expression of BACE1. We found that BACE1 was expressed in the rat carotid body and located in the nerve endings and type II cells but not in type I cells. CIH reduced BACE1 level in the carotid body, and reoxygenation or ROS scavenger alleviated this reduction. Furthermore, we found that CIH augmented the mRNA level of PGC-1α but attenuated the mRNA level of BACE1 in the carotid body. Taken together, our results suggest that CIH promotes the production of ROS that upregulates the level of PGC-1α, which may in turn inhibits the transcription of BACE1, and that a reduction in the BACE1 level may be related to CIH-induced reversible and ROS-dependent carotid body plasticity. Our study provides a new candidate molecule for further study of the mechanism of carotid body plasticity.
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Affiliation(s)
- Chaohong Li
- Henan Key Laboratory of Neural Regeneration and Repairment, Henan Neurology Institute, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Baosheng Zhao
- Department of Thoracic Surgery, The First Affiliated Hospital of Xinxiang Medical University, Weihui, China
| | - Ya-Nan Fan
- Henan Key Laboratory of Neural Regeneration and Repairment, Henan Neurology Institute, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Xianglei Jia
- Henan Key Laboratory of Neural Regeneration and Repairment, Henan Neurology Institute, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Yuzhen Liu
- Henan Key Laboratory of Neural Regeneration and Repairment, Henan Neurology Institute, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
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23
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Wu M, Downie LE, Grover LM, Moakes RJA, Rauz S, Logan A, Jiao H, Hill LJ, Chinnery HR. The neuroregenerative effects of topical decorin on the injured mouse cornea. J Neuroinflammation 2020; 17:142. [PMID: 32366307 PMCID: PMC7199348 DOI: 10.1186/s12974-020-01812-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 04/13/2020] [Indexed: 02/08/2023] Open
Abstract
Background The cornea is innervated with a rich supply of sensory nerves that play important roles in ocular surface health. Any injury or pathology of the corneal nerves increases the risk of dry eye disease and infection. This study aims to evaluate the therapeutic potential of topical decorin to improve corneal nerve regeneration in a mouse model of sterile epithelial abrasion injury. Methods Bilateral central corneal epithelial abrasions (2-mm, Alger Brush) were performed on young C57BL/6 J mice to remove the corneal sensory nerves. Decorin, or vehicle, was applied topically, three times per day for 1 week or every 2 h for 6 h. Spectral-domain optical coherence tomography was performed to measure the abrasion area and corneal thickness. Wholemount immunofluorescence staining was used to assess sensory nerve regeneration (β-tubulin III) and immune cell density (CD45, Iba1, CD11c). To investigate the specific role of dendritic cells (DCs), Cx3cr1gfp/gfp mice, which spontaneously lack resident corneal epithelial DCs, were also investigated. The effect of prophylactic topical administration of recombinant human decorin (applied prior to the abrasion) was also investigated. Nerve tracing (NeuronJ software) was performed to compare recovery of basal nerve axons and superficial nerve terminals in the central and peripheral cornea. Results At 6 h after injury, topical decorin application was associated with greater intraepithelial DC recruitment but no change in re-epithelialisation or corneal thickness, compared to the vehicle control. One week after injury, sub-basal nerve plexus and superficial nerve terminal density were significantly higher in the central cornea in the decorin-treated eyes. The density of corneal stromal macrophages in the decorin-treated eyes and their contralateral eyes was significantly lower compared to saline-treated corneas. No significant improvement in corneal nerve regeneration was observed in Cx3cr1gfp/gfp mice treated with decorin. Conclusions Decorin promotes corneal epithelial nerve regeneration after injury. The neuroregenerative effect of topical decorin was associated with a higher corneal DC density during the acute phase, and fewer macrophages at the study endpoint. The corneal neuroregenerative effects of decorin were absent in mice lacking intraepithelial DCs. Together, these findings support a role for decorin in DC-mediated neuroregeneration following corneal abrasion injury.
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Affiliation(s)
- Mengliang Wu
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, 3053, Australia
| | - Laura E Downie
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, 3053, Australia
| | - Liam M Grover
- School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT, UK
| | - Richard J A Moakes
- School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT, UK
| | - Saaeha Rauz
- Academic Unit of Ophthalmology, Institute of Inflammation and Ageing, Birmingham and Midland Eye Centre, Birmingham, UK.,Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, B15 2TT, UK
| | - Ann Logan
- Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, B15 2TT, UK
| | - Haihan Jiao
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, 3053, Australia
| | - Lisa J Hill
- School of Biomedical Sciences, Institute of Clinical Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Holly R Chinnery
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, 3053, Australia.
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24
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Wang Y, Li B, Xu H, Du S, Liu T, Ren J, Zhang J, Zhang H, Liu Y, Lu L. Growth and elongation of axons through mechanical tension mediated by fluorescent-magnetic bifunctional Fe 3O 4·Rhodamine 6G@PDA superparticles. J Nanobiotechnology 2020; 18:64. [PMID: 32334582 PMCID: PMC7183675 DOI: 10.1186/s12951-020-00621-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/19/2020] [Indexed: 12/12/2022] Open
Abstract
Background The primary strategy to repair peripheral nerve injuries is to bridge the lesions by promoting axon regeneration. Thus, the ability to direct and manipulate neuronal cell axon regeneration has been one of the top priorities in the field of neuroscience. A recent innovative approach for remotely guiding neuronal regeneration is to incorporate magnetic nanoparticles (MNPs) into cells and transfer the resulting MNP-loaded cells into a magnetically sensitive environment to respond to an external magnetic field. To realize this intention, the synthesis and preparation of ideal MNPs is an important challenge to overcome. Results In this study, we designed and prepared novel fluorescent-magnetic bifunctional Fe3O4·Rhodamine 6G@polydopamine superparticles (FMSPs) as neural regeneration therapeutics. With the help of their excellent biocompatibility and ability to interact with neural cells, our in-house fabricated FMSPs can be endocytosed into cells, transported along the axons, and then aggregated in the growth cones. As a result, the mechanical forces generated by FMSPs can promote the growth and elongation of axons and stimulate gene expression associated with neuron growth under external magnetic fields. Conclusions Our work demonstrates that FMSPs can be used as a novel stimulator to promote noninvasive neural regeneration through cell magnetic actuation.![]()
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Affiliation(s)
- Yang Wang
- Department of Hand Surgery, The First Hospital of Jilin University, Changchun, 130021, Jilin, People's Republic of China
| | - Binxi Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, Jilin, People's Republic of China
| | - Hao Xu
- Institute of Translational Medicine, The First Hospital of Jilin University, Changchun, 130021, Jilin, People's Republic of China
| | - Shulin Du
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, Jilin, People's Republic of China
| | - Ting Liu
- Departments of Geriatrics, The First Hospital of Jilin University, Changchun, 130021, Jilin, People's Republic of China
| | - Jingyan Ren
- Department of Hand Surgery, The First Hospital of Jilin University, Changchun, 130021, Jilin, People's Republic of China
| | - Jiayi Zhang
- Department of Hand Surgery, The First Hospital of Jilin University, Changchun, 130021, Jilin, People's Republic of China
| | - Hao Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, Jilin, People's Republic of China
| | - Yi Liu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, Jilin, People's Republic of China.
| | - Laijin Lu
- Department of Hand Surgery, The First Hospital of Jilin University, Changchun, 130021, Jilin, People's Republic of China.
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25
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Offringa-Hup A. Alzheimer's disease: The derailed repair hypothesis. Med Hypotheses 2019; 136:109516. [PMID: 31825804 DOI: 10.1016/j.mehy.2019.109516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 11/27/2019] [Accepted: 11/30/2019] [Indexed: 11/25/2022]
Abstract
A lot of research has been done on Alzheimer's disease, especially focused on factors like amyloid beta, ApoE and tau-protein. However, a complete theory on the disease mechanism of AD, including and connecting all known pathological elements of AD in a conceivable context and order of occurrence, is still lacking. In this article I describe a hypothesis on the entire pathophysiology of Alzheimer's disease, based on the most wellknown pathological elements in AD, filling the gaps with hypothetical mechanisms. This proposed mechanism of derailed repair starts with an insufficiently increased level of injury signalling in the axon by ApoE, DLK, APP, BACE-1, Aβ and iPLA2β, followed by an excessive repair response induced by opening of the mitochondrial permeability transition pore, release of mitochondrial CoA and activation of palmitoylation and massive endocytosis. Excessive compounds, associated with injury signalling and repair, start to accumulate, adding to axonal injury. This increased activation of the repair mechanism causes exhaustion of the repair response by lack of mitochondrial CoA. A vicious circle of increased injury signalling and insufficient repair ensues. Based on this hypothesis, I propose possible markers for early diagnosis and disease-modifying treatments for Alzheimer's disease.
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Pellegatta M, Taveggia C. The Complex Work of Proteases and Secretases in Wallerian Degeneration: Beyond Neuregulin-1. Front Cell Neurosci 2019; 13:93. [PMID: 30949030 PMCID: PMC6436609 DOI: 10.3389/fncel.2019.00093] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 02/26/2019] [Indexed: 01/24/2023] Open
Abstract
After damage, axons in the peripheral nervous system (PNS) regenerate and regrow following a process termed Wallerian degeneration, but the regenerative process is often incomplete and usually the system does not reach full recovery. Key steps to the creation of a permissive environment for axonal regrowth are the trans-differentiation of Schwann cells and the remodeling of the extracellular matrix (ECM). In this review article, we will discuss how proteases and secretases promote effective regeneration and remyelination. We will detail how they control neuregulin-1 (NRG-1) activity at the post-translational level, as the concerted action of alpha, beta and gamma secretases cooperates to balance activating and inhibitory signals necessary for physiological myelination and remyelination. In addition, we will discuss the role of other proteases in nerve repair, among which A Disintegrin And Metalloproteinases (ADAMs) and gamma-secretases substrates. Moreover, we will present how matrix metalloproteinases (MMPs) and proteases of the blood coagulation cascade participate in forming newly synthetized myelin and in regulating axonal regeneration. Overall, we will highlight how a deeper comprehension of secretases and proteases mechanism of action in Wallerian degeneration might be useful to develop new therapies with the potential of readily and efficiently improve the regenerative process.
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Affiliation(s)
- Marta Pellegatta
- Division of Neuroscience and INSPE at IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Carla Taveggia
- Division of Neuroscience and INSPE at IRCCS San Raffaele Scientific Institute, Milan, Italy
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Sun G, Qu S, Wang S, Shao Y, Sun J. Taurine attenuates acrylamide-induced axonal and myelinated damage through the Akt/GSK3β-dependent pathway. Int J Immunopathol Pharmacol 2019; 32:2058738418805322. [PMID: 30354842 PMCID: PMC6202743 DOI: 10.1177/2058738418805322] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Acrylamide (ACR), formed during the Maillard reaction induced by high temperature
in food processing, is one of the main causes of neurodegenerative diseases.
Taurine, a free intracellular β-amino acid, is characterized by many functions,
including antioxidation, anti-inflammatory, and neuroprotective properties. This
promotes its application in the treatment of neurodegenerative diseases. In this
study, the neuroprotective effects of taurine against ACR-induced neurotoxicity
and the potential underlying mechanisms were explored. Rats were intoxicated
with ACR and injected with taurine in different groups for totally 2 weeks
between January and July 2017. Electron microscopic analysis was used to observe
the changes in tissues of the rats. Meanwhile, the levels of proteins including
p-Akt, p-GSK3β, SIM312, and MBP were detected by Western blot. Furthermore, the
GSK3β phosphorylation in taurine-treated dorsal root ganglion (DRG) with ACR was
examined in the presence of the Akt inhibitor, MK-2206. The analysis of
behavioral performances and electron micrographs indicated that taurine
treatment significantly attenuated the toxic manifestations induced by ACR and
stimulated the growth of axons and the medullary sheath, which was associated
with the activation of the Akt/GSK3β signaling pathway. Mechanistically, it was
found that taurine activated GSK3β, leading to significant recovery of the
damage in ACR-induced sciatic nerves. Furthermore, MK-2206, an inhibitor of Akt,
was applied in DRG cells, suggesting that taurine-induced GSK3β phosphorylation
was Akt dependent. Our findings demonstrated that taurine attenuated ACR-induced
neuropathy in vivo, in an Akt/GSK3β-dependent manner. This confirmed the
treatment with taurine to be a novel strategy against ACR-induced
neurotoxicity.
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Affiliation(s)
- Guohua Sun
- The First Affiliated Hospital of Dalian
Medical University, Liaoning, China
| | - Shuxian Qu
- Institute of Cancer Stem Cell, Dalian
Medical University, Dalian, Liaoning, China
| | - Siyi Wang
- The First Affiliated Hospital of Dalian
Medical University, Liaoning, China
| | - Ying Shao
- The First Affiliated Hospital of Dalian
Medical University, Liaoning, China
| | - Jingsong Sun
- The First Affiliated Hospital of Dalian
Medical University, Liaoning, China
- Jingsong Sun, The First Affiliated Hospital
of Dalian Medical University, Liaoning 116011, China.
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Abstract
Alzheimer's disease (AD), the most common cause of age-dependent dementia, is one of the most significant healthcare problems worldwide. Aggravating this situation, drugs that are currently US Food and Drug Administration (FDA)-approved for AD treatment do not prevent or delay disease progression. Therefore, developing effective therapies for AD patients is of critical urgency. Human genetic and clinical studies over the past three decades have indicated that abnormal generation or accumulation of amyloid-β (Aβ) peptides is a likely culprit in AD pathogenesis. Aβ is generated from amyloid precursor protein (APP) via proteolytic cleavage by β-site APP cleaving enzyme 1 (BACE1) (memapsin 2, β-secretase, Asp 2 protease) and γ-secretase. Mice deficient in BACE1 show abrogated production of Aβ. Therefore, pharmacological inhibition of BACE1 is being intensively pursued as a therapeutic approach to treat AD patients. Recent setbacks in clinical trials with BACE1 inhibitors have highlighted the critical importance of understanding how to properly inhibit BACE1 to treat AD patients. This review summarizes the recent studies on the role of BACE1 in synaptic functions as well as our views on BACE1 inhibition as an effective AD treatment.
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Affiliation(s)
- Brati Das
- Department of Neuroscience, Room E4032, UConn Health, 263 Farmington Avenue, Farmington, CT, 06030-3401, USA
| | - Riqiang Yan
- Department of Neuroscience, Room E4032, UConn Health, 263 Farmington Avenue, Farmington, CT, 06030-3401, USA.
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Chiu H, Zou Y, Suzuki N, Hsieh YW, Chuang CF, Wu YC, Chang C. Engulfing cells promote neuronal regeneration and remove neuronal debris through distinct biochemical functions of CED-1. Nat Commun 2018; 9:4842. [PMID: 30451835 PMCID: PMC6242819 DOI: 10.1038/s41467-018-07291-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 10/22/2018] [Indexed: 11/25/2022] Open
Abstract
Two important biological events happen coincidently soon after nerve injury in the peripheral nervous system in C. elegans: removal of axon debris and initiation of axon regeneration. But, it is not known how these two events are co-regulated. Mutants of ced-1, a homolog of Draper and MEGF10, display defects in both events. One model is that those events could be related. But our data suggest that they are actually separable. CED-1 functions in the muscle-type engulfing cells in both events and is enriched in muscle protrusions in close contact with axon debris and regenerating axons. Its two functions occur through distinct biochemical mechanisms; extracellular domain-mediated adhesion for regeneration and extracellular domain binding-induced intracellular domain signaling for debris removal. These studies identify CED-1 in engulfing cells as a receptor in debris removal but as an adhesion molecule in neuronal regeneration, and have important implications for understanding neural circuit repair after injury.
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Affiliation(s)
- Hui Chiu
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, 60607, USA
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, 10617, Taiwan
- Division of Biology and Biological Engineering and HHMI, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Yan Zou
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, 60607, USA
- School of Life Science, ShanghaiTech University, Shanghai, 200031, China
| | - Nobuko Suzuki
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, 60607, USA
| | - Yi-Wen Hsieh
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, 60607, USA
| | - Chiou-Fen Chuang
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, 60607, USA
| | - Yi-Chun Wu
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, 10617, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan
| | - Chieh Chang
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, 60607, USA.
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Tallon C, Farah MH. Beta secretase activity in peripheral nerve regeneration. Neural Regen Res 2017; 12:1565-1574. [PMID: 29171411 PMCID: PMC5696827 DOI: 10.4103/1673-5374.217319] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2017] [Indexed: 12/13/2022] Open
Abstract
While the peripheral nervous system has the capacity to regenerate following a nerve injury, it is often at a slow rate and results in unsatisfactory recovery, leaving patients with reduced function. Many regeneration associated genes have been identified over the years, which may shed some insight into how we can manipulate this intrinsic regenerative ability to enhance repair following peripheral nerve injuries. Our lab has identified the membrane bound protease beta-site amyloid precursor protein-cleaving enzyme 1 (BACE1), or beta secretase, as a potential negative regulator of peripheral nerve regeneration. When beta secretase activity levels are abolished via a null mutation in mice, peripheral regeneration is enhanced following a sciatic nerve crush injury. Conversely, when activity levels are greatly increased by overexpressing beta secretase in mice, nerve regeneration and functional recovery are impaired after a sciatic nerve crush injury. In addition to our work, many substrates of beta secretase have been found to be involved in regulating neurite outgrowth and some have even been identified as regeneration associated genes. In this review, we set out to discuss BACE1 and its substrates with respect to axonal regeneration and speculate on the possibility of utilizing BACE1 inhibitors to enhance regeneration following acute nerve injury and potential uses in peripheral neuropathies.
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Affiliation(s)
- Carolyn Tallon
- Department of Neurology at Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Mohamed H. Farah
- Department of Neurology at Johns Hopkins School of Medicine, Baltimore, MD, USA
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Tallon C, Rockenstein E, Masliah E, Farah MH. Increased BACE1 activity inhibits peripheral nerve regeneration after injury. Neurobiol Dis 2017; 106:147-157. [PMID: 28687442 DOI: 10.1016/j.nbd.2017.07.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 06/26/2017] [Accepted: 07/02/2017] [Indexed: 12/20/2022] Open
Abstract
Axons of the peripheral nervous system possess the capacity to regenerate following injury. Previously, we showed that genetically knocking out Beta-Site APP-Cleaving Enzyme 1 (BACE1) leads to increased nerve regeneration. Two cellular components, macrophages and neurons, contribute to enhanced nerve regeneration in BACE1 knockout mice. Here, we utilized a transgenic mouse model that overexpresses BACE1 in its neurons to investigate whether neuronal BACE1 has an inverse effect on regeneration following nerve injury. We performed a sciatic nerve crush in BACE1 transgenic mice and control wild-type littermates, and evaluated the extent of both morphological and physiological improvements over time. At the earliest time point of 3days, we observed a significant decrease in the length of axonal sprouts growing out from the crush site in BACE1 transgenic mice. At later times (10 and 15days post-crush), there were significant reductions in the number of myelinated axons in the sciatic nerve and the percentage of re-innervated neuromuscular junctions in the gastrocnemius muscle. Transgenic mice had a functional electrophysiological delay in the recovery up to 8weeks post-crush compared to controls. These results indicate that BACE1 activity levels have an inverse effect on peripheral nerve repair after injury. The results obtained in this study provide evidence that neuronal BACE1 activity levels impact peripheral nerve regeneration. This data has clinical relevance by highlighting a novel drug target to enhance peripheral nerve repair, an area which currently does not have any approved therapeutics.
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Affiliation(s)
- Carolyn Tallon
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Edward Rockenstein
- Department of Neurosciences, San Diego School of Medicine, University of California, San Diego, CA, United States
| | - Eliezer Masliah
- Department of Neurosciences, San Diego School of Medicine, University of California, San Diego, CA, United States; Department of Molecular Pathology, San Diego School of Medicine, University of California, San Diego, CA, United States
| | - Mohamed H Farah
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, United States.
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Boerboom A, Dion V, Chariot A, Franzen R. Molecular Mechanisms Involved in Schwann Cell Plasticity. Front Mol Neurosci 2017; 10:38. [PMID: 28261057 PMCID: PMC5314106 DOI: 10.3389/fnmol.2017.00038] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 01/31/2017] [Indexed: 01/09/2023] Open
Abstract
Schwann cell incredible plasticity is a hallmark of the utmost importance following nerve damage or in demyelinating neuropathies. After injury, Schwann cells undergo dedifferentiation before redifferentiating to promote nerve regeneration and complete functional recovery. This review updates and discusses the molecular mechanisms involved in the negative regulation of myelination as well as in the reprogramming of Schwann cells taking place early following nerve lesion to support repair. Significant advance has been made on signaling pathways and molecular components that regulate SC regenerative properties. These include for instance transcriptional regulators such as c-Jun or Notch, the MAPK and the Nrg1/ErbB2/3 pathways. This comprehensive overview ends with some therapeutical applications targeting factors that control Schwann cell plasticity and highlights the need to carefully modulate and balance this capacity to drive nerve repair.
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Affiliation(s)
| | - Valérie Dion
- GIGA-Neurosciences, University of Liège Liège, Belgium
| | - Alain Chariot
- GIGA-Molecular Biology of Diseases, University of LiègeLiège, Belgium; Walloon Excellence in Lifesciences and Biotechnology (WELBIO)Wavre, Belgium
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Lyczek A, Arnold A, Zhang J, Campanelli JT, Janowski M, Bulte JWM, Walczak P. Transplanted human glial-restricted progenitors can rescue the survival of dysmyelinated mice independent of the production of mature, compact myelin. Exp Neurol 2017; 291:74-86. [PMID: 28163160 DOI: 10.1016/j.expneurol.2017.02.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 01/24/2017] [Accepted: 02/01/2017] [Indexed: 01/11/2023]
Abstract
The therapeutic effect of glial progenitor transplantation in diseases of dysmyelination is currently attributed to the formation of new myelin. Using magnetic resonance imaging (MRI), we show that the therapeutic outcome in dysmyelinated shiverer mice is dependent on the extent of cell migration but not the presence of mature and compact myelin. Human or mouse glial restricted progenitors (GRPs) were transplanted into rag2-/- shiverer mouse neonates and followed for over one year. Mouse GRPs produced mature myelin as detected with multi-parametric MRI, but showed limited migration without extended animal lifespan. In sharp contrast, human GRPs migrated extensively and significantly increased animal survival, but production of mature myelin did not occur until 46weeks post-grafting. We conclude that human GRPs can extend the survival of transplanted shiverer mice prior to production of mature myelin, while mouse GRPs fail to extend animal survival despite the early presence of mature myelin. This paradox suggests that transplanted GRPs provide therapeutic benefits through biological processes other than the formation of mature myelin capable to foster rapid nerve conduction, challenging the current dogma of the primary role of myelination in regaining function of the central nervous system.
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Affiliation(s)
- Agatha Lyczek
- Russell H. Morgan Dept. of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Antje Arnold
- Russell H. Morgan Dept. of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Jiangyang Zhang
- Russell H. Morgan Dept. of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States
| | | | - Miroslaw Janowski
- Russell H. Morgan Dept. of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University, Baltimore, MD 21205, United States; Dept. of Neurosurgery, Mossakowski Med. Res. Center, Polish Acad. of Sci., Warsaw, Poland; Dept. of NeuroRepair, Mossakowski Med. Res. Center, Polish Acad. of Sci., Warsaw, Poland
| | - Jeff W M Bulte
- Russell H. Morgan Dept. of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Piotr Walczak
- Russell H. Morgan Dept. of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University, Baltimore, MD 21205, United States; Dept. of Neurology and Neurosurgery, Faculty of Medical Sciences, University of Warmia and Mazury, Olsztyn, Poland.
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34
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Villamil-Ortiz JG, Barrera-Ocampo A, Piedrahita D, Velásquez-Rodríguez CM, Arias-Londoño JD, Cardona-Gómez GP. BACE1 RNAi Restores the Composition of Phosphatidylethanolamine-Derivates Related to Memory Improvement in Aged 3xTg-AD Mice. Front Cell Neurosci 2016; 10:260. [PMID: 27891075 PMCID: PMC5105502 DOI: 10.3389/fncel.2016.00260] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 10/26/2016] [Indexed: 01/16/2023] Open
Abstract
β-amyloid (Aβ) is produced by the β-secretase 1 (BACE1)-mediated enzymatic cleavage of the amyloid precursor protein through the amyloidogenic pathway, making BACE1 a therapeutic target against Alzheimer’s disease (AD). Alterations in lipid metabolism are a risk factor for AD by an unknown mechanism. The objective of this study was to determine the effect of RNA interference against BACE1 (shBACEmiR) on the phospholipid profile in hippocampal CA1 area in aged 3xTg-AD mice after 6 and 12 months of treatment compared to aged PS1KI mice. The shBACEmiR treatment induced cognitive function recovery and restored mainly the fatty acid composition of lysophosphatidylethanolamine and etherphosphatidylethanolamine, reduced the cPLA2’s phosphorylation, down-regulated the levels of arachidonic acid and COX2 in the hippocampi of 3xTg-AD mice. Together, our findings suggest, for the first time, that BACE1 silencing restores phospholipids composition which could favor the recovery of cellular homeostasis and cognitive function in the hippocampus of triple transgenic AD mice.
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Affiliation(s)
- Javier G Villamil-Ortiz
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Sede de Investigación Universitaria, University of Antioquia Medellín, Colombia
| | - Alvaro Barrera-Ocampo
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Sede de Investigación Universitaria, University of Antioquia Medellín, Colombia
| | - Diego Piedrahita
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Sede de Investigación Universitaria, University of Antioquia Medellín, Colombia
| | | | | | - Gloria P Cardona-Gómez
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Sede de Investigación Universitaria, University of Antioquia Medellín, Colombia
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Altmann C, Vasic V, Hardt S, Heidler J, Häussler A, Wittig I, Schmidt MHH, Tegeder I. Progranulin promotes peripheral nerve regeneration and reinnervation: role of notch signaling. Mol Neurodegener 2016; 11:69. [PMID: 27770818 PMCID: PMC5075406 DOI: 10.1186/s13024-016-0132-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 09/28/2016] [Indexed: 01/11/2023] Open
Abstract
Background Peripheral nerve injury is a frequent cause of lasting motor deficits and chronic pain. Although peripheral nerves are capable of regrowth they often fail to re-innervate target tissues. Results Using newly generated transgenic mice with inducible neuronal progranulin overexpression we show that progranulin accelerates axonal regrowth, restoration of neuromuscular synapses and recovery of sensory and motor functions after injury of the sciatic nerve. Oppositely, progranulin deficient mice have long-lasting deficits in motor function tests after nerve injury due to enhanced losses of motor neurons and stronger microglia activation in the ventral horn of the spinal cord. Deep proteome and gene ontology (GO) enrichment analysis revealed that the proteins upregulated in progranulin overexpressing mice were involved in ‘regulation of transcription’ and ‘response to insulin’ (GO terms). Transcription factor prediction pointed to activation of Notch signaling and indeed, co-immunoprecipitation studies revealed that progranulin bound to the extracellular domain of Notch receptors, and this was functionally associated with higher expression of Notch target genes in the dorsal root ganglia of transgenic mice with neuronal progranulin overexpression. Functionally, these transgenic mice recovered normal gait and running, which was not achieved by controls and was stronger impaired in progranulin deficient mice. Conclusion We infer that progranulin activates Notch signaling pathways, enhancing thereby the regenerative capacity of partially injured neurons, which leads to improved motor function recovery. Graphical abstract ![]()
Electronic supplementary material The online version of this article (doi:10.1186/s13024-016-0132-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Christine Altmann
- Institute of Clinical Pharmacology, Goethe-University Hospital, Frankfurt, Germany
| | - Verica Vasic
- Molecular Signal Transduction Laboratories, Institute for Microscopic Anatomy and Neurobiology, Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn2), University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Stefanie Hardt
- Institute of Clinical Pharmacology, Goethe-University Hospital, Frankfurt, Germany
| | - Juliana Heidler
- Functional Proteomics, SFB815 Core Unit, Goethe-University, Frankfurt, Germany
| | - Annett Häussler
- Institute of Clinical Pharmacology, Goethe-University Hospital, Frankfurt, Germany
| | - Ilka Wittig
- Functional Proteomics, SFB815 Core Unit, Goethe-University, Frankfurt, Germany
| | - Mirko H H Schmidt
- Molecular Signal Transduction Laboratories, Institute for Microscopic Anatomy and Neurobiology, Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn2), University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Irmgard Tegeder
- Institute of Clinical Pharmacology, Goethe-University Hospital, Frankfurt, Germany.
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Tasnim A, Rammelkamp Z, Slusher AB, Wozniak K, Slusher BS, Farah MH. Paclitaxel causes degeneration of both central and peripheral axon branches of dorsal root ganglia in mice. BMC Neurosci 2016; 17:47. [PMID: 27401104 PMCID: PMC4940970 DOI: 10.1186/s12868-016-0285-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 05/25/2016] [Indexed: 01/05/2023] Open
Abstract
Background Peripheral neuropathy is a common and dose-limiting side effect of many cancer chemotherapies. The taxane agents, including paclitaxel (Taxol®), are effective chemotherapeutic drugs but cause degeneration of predominantly large myelinated afferent sensory fibers of the peripheral nervous system in humans and animal models. Dorsal root ganglia (DRG) neurons are sensory neurons that have unipolar axons each with two branches: peripheral and central. While taxane agents induce degeneration of peripheral axons, whether they also cause degeneration of central nervous system axons is not clear. Using a mouse model of paclitaxel-induced neuropathy, we investigated the effects of paclitaxel on the central branches of sensory axons. Results We observed that in the spinal cords of paclitaxel-intoxicated mice, degenerated axons were present in the dorsal columns, where the central branches of DRG axons ascend rostrally. In the peripheral nerves, degenerated myelinated fibers were present in significantly greater numbers in distal segments than in proximal segments indicating that this model exhibits the distal-to-proximal degeneration pattern generally observed in human peripheral nerve disorders. Conclusions We conclude that paclitaxel causes degeneration of both the peripheral and central branches of DRG axons, a finding that has implications for the site and mode of action of chemotherapy agents on the nervous system.
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Affiliation(s)
- Aniqa Tasnim
- Neuromuscular Division, Department of Neurology, Johns Hopkins University School of Medicine, The John G. Rangos Sr. Building, Room 239, 855 N. Wolfe Street, Baltimore, MD, 21205, USA.,Harvard University, Boston, MA, USA
| | - Zoe Rammelkamp
- Neuromuscular Division, Department of Neurology, Johns Hopkins University School of Medicine, The John G. Rangos Sr. Building, Room 239, 855 N. Wolfe Street, Baltimore, MD, 21205, USA.,University of Maryland Medical School, Baltimore, MD, USA
| | - Amy B Slusher
- Neuromuscular Division, Department of Neurology, Johns Hopkins University School of Medicine, The John G. Rangos Sr. Building, Room 239, 855 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Krystyna Wozniak
- Johns Hopkins Drug Discovery Program, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Barbara S Slusher
- Neuromuscular Division, Department of Neurology, Johns Hopkins University School of Medicine, The John G. Rangos Sr. Building, Room 239, 855 N. Wolfe Street, Baltimore, MD, 21205, USA.,Johns Hopkins Drug Discovery Program, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mohamed H Farah
- Neuromuscular Division, Department of Neurology, Johns Hopkins University School of Medicine, The John G. Rangos Sr. Building, Room 239, 855 N. Wolfe Street, Baltimore, MD, 21205, USA.
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37
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Liu L, Fissel JA, Tasnim A, Borzan J, Gocke A, Calabresi PA, Farah MH. Increased TNFR1 expression and signaling in injured peripheral nerves of mice with reduced BACE1 activity. Neurobiol Dis 2016; 93:21-7. [PMID: 27080468 DOI: 10.1016/j.nbd.2016.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 03/01/2016] [Accepted: 04/06/2016] [Indexed: 11/19/2022] Open
Abstract
Hematogenous macrophages remove myelin debris from injured peripheral nerves to provide a micro-environment conducive to axonal regeneration. Previously, we observed that injured peripheral nerves from Beta-site APP Cleaving Enzyme 1 (BACE1) knockout (KO) mice displayed earlier influx of and enhanced phagocytosis by macrophages when compared to wild-type (WT) mice. These observations suggest that BACE1 might regulate macrophage influx into distal stumps of injured nerves. To determine through which pathway BACE1 influences macrophage influx, we used a mouse inflammation antibody array to assay the expression of inflammation-related proteins in injured nerves of BACE1 KO and WT mice. The most significant change was in expression of tumor necrosis factor receptor 1 (TNFR1) in the distal stump of injured BACE1 KO nerves. Western blotting of protein extracts confirmed increased expression of TNFR1 and its downstream transcriptional factor NFκB in the BACE1 KO distal stumps. Additionally, treatment of WT mice with a BACE1 inhibitor resulted in increased TNFR1 expression and signaling in the distal stump of injured nerves. Exogenous TNFα increased nuclear translocation of p65 NFκB in BACE1 KO tissue and cultured fibroblasts compared with control WT. BACE1 regulates TNFR1 expression at the level of gene expression and not through proteolytic processing. The accelerated macrophage influx in injured nerves of BACE1 KO mice correlates with increased expression and signaling via TNFR1, indicating a link between BACE1 activity and TNFR1 expression/signaling that might contribute to repair of the injured nervous system.
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Affiliation(s)
- Lijuan Liu
- Department of Neurology, Johns Hopkins University School of Medicine, United States
| | - John A Fissel
- Department of Neurology, Johns Hopkins University School of Medicine, United States
| | - Aniqa Tasnim
- Department of Neurology, Johns Hopkins University School of Medicine, United States
| | - Jasenka Borzan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, United States
| | - Anne Gocke
- Department of Neurology, Johns Hopkins University School of Medicine, United States
| | - Peter A Calabresi
- Department of Neurology, Johns Hopkins University School of Medicine, United States
| | - Mohamed H Farah
- Department of Neurology, Johns Hopkins University School of Medicine, United States.
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38
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Gong B, Radulovic M, Figueiredo-Pereira ME, Cardozo C. The Ubiquitin-Proteasome System: Potential Therapeutic Targets for Alzheimer's Disease and Spinal Cord Injury. Front Mol Neurosci 2016; 9:4. [PMID: 26858599 PMCID: PMC4727241 DOI: 10.3389/fnmol.2016.00004] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 01/07/2016] [Indexed: 01/20/2023] Open
Abstract
The ubiquitin-proteasome system (UPS) is a crucial protein degradation system in eukaryotes. Herein, we will review advances in the understanding of the role of several proteins of the UPS in Alzheimer’s disease (AD) and functional recovery after spinal cord injury (SCI). The UPS consists of many factors that include E3 ubiquitin ligases, ubiquitin hydrolases, ubiquitin and ubiquitin-like molecules, and the proteasome itself. An extensive body of work links UPS dysfunction with AD pathogenesis and progression. More recently, the UPS has been shown to have vital roles in recovery of function after SCI. The ubiquitin hydrolase (Uch-L1) has been proposed to increase cellular levels of mono-ubiquitin and hence to increase rates of protein turnover by the UPS. A low Uch-L1 level has been linked with Aβ accumulation in AD and reduced neuroregeneration after SCI. One likely mechanism for these beneficial effects of Uch-L1 is reduced turnover of the PKA regulatory subunit and consequently, reduced signaling via CREB. The neuron-specific F-box protein Fbx2 ubiquitinates β-secretase thus targeting it for proteasomal degradation and reducing generation of Aβ. Both Uch-L1 and Fbx2 improve synaptic plasticity and cognitive function in mouse AD models. The role of Fbx2 after SCI has not been examined, but abolishing ß-secretase reduces neuronal recovery after SCI, associated with reduced myelination. UBB+1, which arises through a frame-shift mutation in the ubiquitin gene that adds 19 amino acids to the C-terminus of ubiquitin, inhibits proteasomal function and is associated with increased neurofibrillary tangles in patients with AD, Pick’s disease and Down’s syndrome. These advances in understanding of the roles of the UPS in AD and SCI raise new questions but, also, identify attractive and exciting targets for potential, future therapeutic interventions.
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Affiliation(s)
- Bing Gong
- Department of Medicine, Mount Sinai School of MedicineNew York, NY, USA; Medicine, James J. Peters Veteran Affairs Medical CenterBronx, NY, USA
| | - Miroslav Radulovic
- Department of Medicine, Mount Sinai School of MedicineNew York, NY, USA; Medicine, James J. Peters Veteran Affairs Medical CenterBronx, NY, USA; National Center of Excellence for the Medical Consequences of Spinal Cord Injury (SCI)Bronx, NY, USA
| | - Maria E Figueiredo-Pereira
- Department of Biological Sciences, Hunter College, and the Graduate School and University Center, The City University of New York New York, NY, USA
| | - Christopher Cardozo
- Department of Medicine, Mount Sinai School of MedicineNew York, NY, USA; Medicine, James J. Peters Veteran Affairs Medical CenterBronx, NY, USA; National Center of Excellence for the Medical Consequences of Spinal Cord Injury (SCI)Bronx, NY, USA
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Chen Z, Zhang W, Ni L, Wang G, Cao Y, Wu W, Sun C, Yuan D, Ni H, Wang Y, Yang H. Spatiotemporal Expression of Poly(rC)-Binding Protein PCBP2 Modulates Schwann Cell Proliferation After Sciatic Nerve Injury. Cell Mol Neurobiol 2015; 36:725-35. [PMID: 26250704 DOI: 10.1007/s10571-015-0253-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 07/31/2015] [Indexed: 12/16/2022]
Abstract
Poly(C)-binding proteins (PCBPs), also known as RNA-binding proteins, interact in a sequence-specific fashion with single-stranded poly(C). It was reported that PCBP2 contributed to gastric cancer proliferation and survival through miR-34a, and knockdown of PCBP2 inhibited glioma proliferation through inhibition of cell cycle progression. In addition, PCBP2 might play a critical role in the regulation of cortical neurons apoptosis induced by hypoxia or ischemia. Because of the essential role of PCBP2 in nervous system and cell growth, we investigated the spatiotemporal expression of PCBP2 in a rat sciatic nerve crush (SNC) model. We detected the upregulated expression of PCBP2 in Schwann cell after SNC. Besides, the peak expression of PCBP2 was in parallel with proliferation cell nuclear antigen. In vitro, we observed increased expression of PCBP2 during the process of TNF-α-induced Schwann cell proliferation. Specially, PCBP2-specific siRNA-transfected Schwann cell showed significantly decreased ability for proliferation. Together, all these data indicated that the change of PCBP2 protein expression was associated with Schwann cell proliferation after the trauma of the peripheral nervous system.
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Affiliation(s)
- Zhigang Chen
- Department of Orthopaedic Surgery, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, Jiangsu, People's Republic of China.,Department of Orthopedic Surgery, The Affiliated Hai'an Hospital of Nantong University, 17 Zhongba Middle Road, Hai'an, 226600, Jiangsu, People's Republic of China
| | - Weidong Zhang
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Li Ni
- Department of Orthopaedic Surgery, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, Jiangsu, People's Republic of China
| | - Genlin Wang
- Department of Orthopaedic Surgery, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, Jiangsu, People's Republic of China
| | - Yi Cao
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Weijie Wu
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Chi Sun
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Damin Yuan
- Department of Immunology, Medical College, Nantong University, Nantong, 226001, People's Republic of China
| | - Haidan Ni
- Department of Neurology, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Youhua Wang
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Huilin Yang
- Department of Orthopaedic Surgery, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, Jiangsu, People's Republic of China.
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40
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Zhang Y, Chopp M, Liu XS, Kassis H, Wang X, Li C, An G, Zhang ZG. MicroRNAs in the axon locally mediate the effects of chondroitin sulfate proteoglycans and cGMP on axonal growth. Dev Neurobiol 2015; 75:1402-19. [PMID: 25788427 DOI: 10.1002/dneu.22292] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 02/25/2015] [Accepted: 03/16/2015] [Indexed: 01/08/2023]
Abstract
Axonal miRNAs locally regulate axonal growth by modulating local protein composition. Whether localized miRNAs in the axon mediate the inhibitory effect of Chondroitin sulfate proteoglycans (CSPGs) on the axon remains unknown. We showed that in cultured cortical neurons, axonal application of CSPGs inhibited axonal growth and altered axonal miRNA profiles, whereas elevation of axonal cyclic guanosine monophosphate (cGMP) levels by axonal application of sildenafil reversed the effect of CSPGs on inhibition of axonal growth and on miRNA profiles. Specifically, CSPGs elevated and reduced axonal levels of miR-29c and integrin β1 (ITGB1) proteins, respectively, while elevation of cGMP levels overcame these CSPG effects. Gain-of- and loss-of-function experiments demonstrated that miR-29c in the distal axon mediates axonal growth downstream of CSPGs and cGMP by regulating axonal protein levels of ITGB1, FAK, and RhoA. Together, our data demonstrate that axonal miRNAs play an important role in mediating the inhibitory action of CSPGs on axonal growth and that miR-29c at least partially mediates this process.
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Affiliation(s)
- Yi Zhang
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, 48202
| | - Michael Chopp
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, 48202.,Department of Physics, Oakland University, Rochester, Michigan, 48309
| | - Xian Shuang Liu
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, 48202
| | - Haifa Kassis
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, 48202
| | - Xinli Wang
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, 48202
| | - Chao Li
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, 48202
| | | | - Zheng Gang Zhang
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, 48202
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41
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Christianson MG, Lo DC. Differential roles of Aβ processing in hypoxia-induced axonal damage. Neurobiol Dis 2015; 77:94-105. [PMID: 25771168 DOI: 10.1016/j.nbd.2015.02.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 01/28/2015] [Accepted: 02/11/2015] [Indexed: 11/25/2022] Open
Abstract
Axonopathy is a common and early phase in neurodegenerative and traumatic CNS diseases. Recent work suggests that amyloid β (Aβ) produced from amyloid precursor protein (APP) may be a critical downstream mediator of CNS axonopathy in CNS diseases, particularly those associated with hypoxia. We critically tested this hypothesis in an adult retinal explant system that preserves the three-dimensional organization of the retina while permitting direct imaging of two cardinal features of early-stage axonopathy: axonal structural integrity and axonal transport capacity. Using this system, we found via pharmacological inhibition and genetic deletion of APP that production of Aβ is a necessary step in structural compromise of retinal ganglion cell (RGC) axons induced by the disease-relevant stressor hypoxia. However, identical blockade of Aβ production was not sufficient to protect axons from associated hypoxia-induced reduction in axonal transport. Thus, Aβ mediates distinct facets of hypoxia-induced axonopathy and may represent a functionally selective pharmacological target for therapies directed against early-stage axonopathy in CNS diseases.
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Affiliation(s)
- Melissa G Christianson
- Center for Drug Discovery and Department of Neurobiology, Duke University Medical Center, Durham, NC, USA.
| | - Donald C Lo
- Center for Drug Discovery and Department of Neurobiology, Duke University Medical Center, Durham, NC, USA
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Butler CR, Brodney MA, Beck EM, Barreiro G, Nolan CE, Pan F, Vajdos F, Parris K, Varghese AH, Helal CJ, Lira R, Doran SD, Riddell DR, Buzon LM, Dutra JK, Martinez-Alsina LA, Ogilvie K, Murray JC, Young JM, Atchison K, Robshaw A, Gonzales C, Wang J, Zhang Y, O’Neill BT. Discovery of a Series of Efficient, Centrally Efficacious BACE1 Inhibitors through Structure-Based Drug Design. J Med Chem 2015; 58:2678-702. [DOI: 10.1021/jm501833t] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
| | | | | | - Gabriela Barreiro
- Departamento
de Inovação, Eurofarma Laboratorios S.A., Avenida Vereador
José Diniz, 3465, Campo Belo, São Paulo, Brasil
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Jinlong Wang
- WuXi AppTec, 288 Fute Zhong Road, Waigaoqiao Free Trade Zone, Shanghai 200131, China
| | - Yong Zhang
- WuXi AppTec, 288 Fute Zhong Road, Waigaoqiao Free Trade Zone, Shanghai 200131, China
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43
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Collagen VI regulates peripheral nerve regeneration by modulating macrophage recruitment and polarization. Acta Neuropathol 2015; 129:97-113. [PMID: 25421425 DOI: 10.1007/s00401-014-1369-9] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 11/15/2014] [Accepted: 11/17/2014] [Indexed: 12/22/2022]
Abstract
Macrophages contribute to peripheral nerve regeneration and produce collagen VI, an extracellular matrix protein involved in nerve function. Here, we show that collagen VI is critical for macrophage migration and polarization during peripheral nerve regeneration. Nerve injury induces a robust upregulation of collagen VI, whereas lack of collagen VI in Col6a1(-/-) mice delays peripheral nerve regeneration. In vitro studies demonstrated that collagen VI promotes macrophage migration and polarization via AKT and PKA pathways. Col6a1(-/-) macrophages exhibit impaired migration abilities and reduced antiinflammatory (M2) phenotype polarization, but are prone to skewing toward the proinflammatory (M1) phenotype. In vivo, macrophage recruitment and M2 polarization are impaired in Col6a1(-/-) mice after nerve injury. The delayed nerve regeneration of Col6a1(-/-) mice is induced by macrophage deficits and rejuvenated by transplantation of wild-type bone marrow cells. These results identify collagen VI as a novel regulator for peripheral nerve regeneration by modulating macrophage function.
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44
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Morrison BM, Tsingalia A, Vidensky S, Lee Y, Jin L, Farah MH, Lengacher S, Magistretti PJ, Pellerin L, Rothstein JD. Deficiency in monocarboxylate transporter 1 (MCT1) in mice delays regeneration of peripheral nerves following sciatic nerve crush. Exp Neurol 2014; 263:325-38. [PMID: 25447940 DOI: 10.1016/j.expneurol.2014.10.018] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 10/16/2014] [Accepted: 10/22/2014] [Indexed: 12/20/2022]
Abstract
Peripheral nerve regeneration following injury occurs spontaneously, but many of the processes require metabolic energy. The mechanism of energy supply to axons has not previously been determined. In the central nervous system, monocarboxylate transporter 1 (MCT1), expressed in oligodendroglia, is critical for supplying lactate or other energy metabolites to axons. In the current study, MCT1 is shown to localize within the peripheral nervous system to perineurial cells, dorsal root ganglion neurons, and Schwann cells by MCT1 immunofluorescence in wild-type mice and tdTomato fluorescence in MCT1 BAC reporter mice. To investigate whether MCT1 is necessary for peripheral nerve regeneration, sciatic nerves of MCT1 heterozygous null mice are crushed and peripheral nerve regeneration was quantified electrophysiologically and anatomically. Compound muscle action potential (CMAP) recovery is delayed from a median of 21 days in wild-type mice to greater than 38 days in MCT1 heterozygote null mice. In fact, half of the MCT1 heterozygote null mice have no recovery of CMAP at 42 days, while all of the wild-type mice recovered. In addition, muscle fibers remain 40% more atrophic and neuromuscular junctions 40% more denervated at 42 days post-crush in the MCT1 heterozygote null mice than wild-type mice. The delay in nerve regeneration is not only in motor axons, as the number of regenerated axons in the sural sensory nerve of MCT1 heterozygote null mice at 4 weeks and tibial mixed sensory and motor nerve at 3 weeks is also significantly reduced compared to wild-type mice. This delay in regeneration may be partly due to failed Schwann cell function, as there is reduced early phagocytosis of myelin debris and remyelination of axon segments. These data for the first time demonstrate that MCT1 is critical for regeneration of both sensory and motor axons in mice following sciatic nerve crush.
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Affiliation(s)
- Brett M Morrison
- Department of Neurology, School of Medicine, The Johns Hopkins University, 855 North Wolfe Street, Baltimore, MD 21205, USA.
| | - Akivaga Tsingalia
- Department of Neurology, School of Medicine, The Johns Hopkins University, 855 North Wolfe Street, Baltimore, MD 21205, USA.
| | - Svetlana Vidensky
- Department of Neurology, School of Medicine, The Johns Hopkins University, 855 North Wolfe Street, Baltimore, MD 21205, USA; Brain Science Institute, School of Medicine, The Johns Hopkins University, 855 North Wolfe Street, Baltimore, MD 21205, USA.
| | - Youngjin Lee
- Department of Neurology, School of Medicine, The Johns Hopkins University, 855 North Wolfe Street, Baltimore, MD 21205, USA; Brain Science Institute, School of Medicine, The Johns Hopkins University, 855 North Wolfe Street, Baltimore, MD 21205, USA.
| | - Lin Jin
- Department of Neurology, School of Medicine, The Johns Hopkins University, 855 North Wolfe Street, Baltimore, MD 21205, USA; Brain Science Institute, School of Medicine, The Johns Hopkins University, 855 North Wolfe Street, Baltimore, MD 21205, USA.
| | - Mohamed H Farah
- Department of Neurology, School of Medicine, The Johns Hopkins University, 855 North Wolfe Street, Baltimore, MD 21205, USA.
| | - Sylvain Lengacher
- Laboratory of Neuroenergetics and Cellular Dynamics, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland.
| | - Pierre J Magistretti
- Division of Biological and Environmental Sciences and Engineering, KAUST, Thuwal, Saudi Arabia; Brain Mind Institute, Ecole Polytechnique Federale de Lausanne, SV2511, Station 19, CH-1015 Lausanne, Switzerland.
| | - Luc Pellerin
- Department of Fundamental Neurosciences, University of Lausanne, 7 Rue du Bugnon, 1005 Lausanne, Switzerland.
| | - Jeffrey D Rothstein
- Department of Neurology, School of Medicine, The Johns Hopkins University, 855 North Wolfe Street, Baltimore, MD 21205, USA; Brain Science Institute, School of Medicine, The Johns Hopkins University, 855 North Wolfe Street, Baltimore, MD 21205, USA.
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Yan XX, Ma C, Gai WP, Cai H, Luo XG. Can BACE1 inhibition mitigate early axonal pathology in neurological diseases? J Alzheimers Dis 2014; 38:705-18. [PMID: 24081378 DOI: 10.3233/jad-131400] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
β-Secretase-1 (BACE1) is the rate-limiting enzyme for the genesis of amyloid-β (Aβ) peptides, the main constituents of the amyloid plaques in the brains of Alzheimer's disease (AD) patients. BACE1 is being evaluated as an anti-Aβ target for AD therapy. Recent studies indicate that BACE1 elevation is associated with axonal and presynaptic pathology during plaque development. Evidence also points to a biological role for BACE1 in axonal outgrowth and synapse formation during development. Axonal, including presynaptic, pathology exists in AD as well as many other neurological disorders such as Parkinson's disease, epilepsy, stroke, and trauma. In this review, we discuss pharmaceutical BACE1 inhibition as a therapeutic option for axonal pathogenesis, in addition to amyloid pathology. We first introduce the amyloidogenic processing of amyloid-β protein precursor and describe the normal expression pattern of the amyloidogenic proteins in the brain, with an emphasis on BACE1. We then address BACE1 elevation relative to amyloid plaque development, followed by updating recent understanding of a neurotrophic role of BACE1 in axon and synapse development. We further elaborate the occurrence of axonal pathology in some other neurological conditions. Finally, we propose pharmacological inhibition of excessive BACE1 activity as an option to mitigate early axonal pathology occurring in AD and other neurological disorders.
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Affiliation(s)
- Xiao-Xin Yan
- Department of Anatomy and Neurobiology, Central South University Xiangya School of Medicine, Changsha, Hunan, China
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46
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Liu Y, Liu Y, Nie X, Cao J, Zhu X, Zhang W, Liu Z, Mao X, Yan S, Ni Y, Wang Y. Up-regulation of HDAC4 is associated with Schwann cell proliferation after sciatic nerve crush. Neurochem Res 2014; 39:2105-17. [PMID: 25103231 DOI: 10.1007/s11064-014-1401-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 06/29/2014] [Accepted: 07/24/2014] [Indexed: 12/12/2022]
Abstract
Histone deacetylase 4 (HDAC4), a member of the class IIa HDACs subfamily, has emerged as a critical regulator of cell growth, differentiation, and migration in various cell types. It was reported that HDAC4 stimulated colon cell proliferation via repression of p21. Also, HDAC4 contributes to platelet-derived growth factor-BB-induced proliferation and migration of vascular smooth muscle cells. Furthermore, HDAC4 may play an important role in the regulation of neuronal differentiation and survival. However, the role of HDAC4 in the process of peripheral nervous system regeneration after injury remains virtually unknown. Herein, we investigated the spatiotemporal expression of HDAC4 in a rat sciatic nerve crush model. We found that sciatic nerve crush induced up-regulated expression of HDAC4 in Schwann cells. Moreover, the expression of the proliferation marker Ki-67 exhibited a similar tendency with that of HDAC4. In cell cultures, we observed increased expression of HDAC4 during the process of TNF-α-induced Schwann cell proliferation, whereas the protein level of p21 was down-regulated. Interference of HDAC4 led to enhanced expression of p21 and impaired proliferation of Schwan cells. Taken together, our findings implicated that HDAC4 was up-regulated in the sciatic nerve after crush, which was associated with proliferation of Schwann cells.
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Affiliation(s)
- Yonghua Liu
- Department of Pathogen Biology, Medical College, Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
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Vassar R, Kuhn PH, Haass C, Kennedy ME, Rajendran L, Wong PC, Lichtenthaler SF. Function, therapeutic potential and cell biology of BACE proteases: current status and future prospects. J Neurochem 2014; 130:4-28. [PMID: 24646365 PMCID: PMC4086641 DOI: 10.1111/jnc.12715] [Citation(s) in RCA: 235] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 03/12/2014] [Accepted: 03/14/2014] [Indexed: 01/18/2023]
Abstract
The β-site APP cleaving enzymes 1 and 2 (BACE1 and BACE2) were initially identified as transmembrane aspartyl proteases cleaving the amyloid precursor protein (APP). BACE1 is a major drug target for Alzheimer's disease because BACE1-mediated cleavage of APP is the first step in the generation of the pathogenic amyloid-β peptides. BACE1, which is highly expressed in the nervous system, is also required for myelination by cleaving neuregulin 1. Several recent proteomic and in vivo studies using BACE1- and BACE2-deficient mice demonstrate a much wider range of physiological substrates and functions for both proteases within and outside of the nervous system. For BACE1 this includes axon guidance, neurogenesis, muscle spindle formation, and neuronal network functions, whereas BACE2 was shown to be involved in pigmentation and pancreatic β-cell function. This review highlights the recent progress in understanding cell biology, substrates, and functions of BACE proteases and discusses the therapeutic options and potential mechanism-based liabilities, in particular for BACE inhibitors in Alzheimer's disease. The protease BACE1 is a major drug target in Alzheimer disease. Together with its homolog BACE2, both proteases have an increasing number of functions within and outside of the nervous system. This review highlights recent progress in understanding cell biology, substrates, and functions of BACE proteases and discusses the therapeutic options and potential mechanism-based liabilities, in particular for BACE inhibitors in Alzheimer disease.
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Affiliation(s)
- Robert Vassar
- Department of Cell and Molecular Biology, Feinberg University School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Peer-Hendrik Kuhn
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- Institute for Advanced Study, Technische Universität München, Garching, Germany
| | - Christian Haass
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
- Adolf-Butenandt Institute, Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany
| | - Matthew E. Kennedy
- Neurosciences, Merck Research Labs, Boston, Massachusetts, USA
- Division of Psychiatry Research, University of Zurich, Zurich, Switzerland
| | - Lawrence Rajendran
- Systems and Cell Biology of Neurodegeneration, Division of Psychiatry Research, University of Zurich, Zurich, Switzerland
- Graduate programs of the Zurich Center for Integrative Human Physiology and Zurich Neuroscience Center, University of Zurich, Zurich, Switzerland
| | - Philip C. Wong
- Departments of Pathology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Stefan F. Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- Institute for Advanced Study, Technische Universität München, Garching, Germany
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
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48
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Pajoohesh-Ganji A, Burns MP, Pal-Ghosh S, Tadvalkar G, Hokenbury NG, Stepp MA, Faden AI. Inhibition of amyloid precursor protein secretases reduces recovery after spinal cord injury. Brain Res 2014; 1560:73-82. [PMID: 24630972 DOI: 10.1016/j.brainres.2014.02.049] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 02/24/2014] [Accepted: 02/25/2014] [Indexed: 12/18/2022]
Abstract
Amyloid-β (Aβ) is produced through the enzymatic cleavage of amyloid precursor protein (APP) by β (Bace1) and γ-secretases. The accumulation and aggregation of Aβ as amyloid plaques is the hallmark pathology of Alzheimer׳s disease and has been found in other neurological disorders, such as traumatic brain injury and multiple sclerosis. Although the role of Aβ after injury is not well understood, several studies have reported a negative correlation between Aβ formation and functional outcome. In this study we show that levels of APP, the enzymes cleaving APP (Bace1 and γ-secretase), and Aβ are significantly increased from 1 to 3 days after impact spinal cord injury (SCI) in mice. To determine the role of Aβ after SCI, we reduced or inhibited Aβ in vivo through pharmacological (using DAPT) or genetic (Bace1 knockout mice) approaches. We found that these interventions significantly impaired functional recovery as evaluated by white matter sparing and behavioral testing. These data are consistent with a beneficial role for Aβ after SCI.
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Affiliation(s)
| | - Mark P Burns
- Georgetown University, Washington, DC, United States
| | | | - Gauri Tadvalkar
- The George Washington University, Washington, DC, United States
| | - Nicole G Hokenbury
- The George Washington University, Washington, DC, United States; Georgetown University, Washington, DC, United States; University of Maryland, Baltimore, United States
| | - Mary Ann Stepp
- The George Washington University, Washington, DC, United States
| | - Alan I Faden
- University of Maryland, Baltimore, United States
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Evin G, Barakat A. Critical analysis of the use of β-site amyloid precursor protein-cleaving enzyme 1 inhibitors in the treatment of Alzheimer's disease. Degener Neurol Neuromuscul Dis 2014; 4:1-19. [PMID: 32669897 PMCID: PMC7337240 DOI: 10.2147/dnnd.s41056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 03/06/2014] [Indexed: 01/18/2023] Open
Abstract
Alzheimer’s disease (AD) is the major cause of dementia in the elderly and an unmet clinical challenge. A variety of therapies that are currently under development are directed to the amyloid cascade. Indeed, the accumulation and toxicity of amyloid-β (Aβ) is believed to play a central role in the etiology of the disease, and thus rational interventions are aimed at reducing the levels of Aβ in the brain. Targeting β-site amyloid precursor protein-cleaving enzyme (BACE)-1 represents an attractive strategy, as this enzyme catalyzes the initial and rate-limiting step in Aβ production. Observation of increased levels of BACE1 and enzymatic activity in the brain, cerebrospinal fluid, and platelets of patients with AD and mild cognitive impairment supports the potential benefits of BACE1 inhibition. Numerous potent inhibitors have been generated, and many of these have been proved to lower Aβ levels in the brain of animal models. Over 10 years of intensive research on BACE1 inhibitors has now culminated in advancing half a dozen of these drugs into human trials, yet translating the in vitro and cellular efficacy of BACE1 inhibitors into preclinical and clinical trials represents a challenge. This review addresses the promises and also the potential problems associated with BACE1 inhibitors for AD therapy, as the complex biological function of BACE1 in the brain is becoming unraveled.
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Affiliation(s)
- Genevieve Evin
- Oxidation Biology Laboratory, Mental Health Research Institute, Florey Institute of Neuroscience and Mental Health, University of Melbourne.,Department of Pathology, University of Melbourne, Parkville, VIC, Australia
| | - Adel Barakat
- Department of Pathology, University of Melbourne, Parkville, VIC, Australia
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Farah MH. BACE1 influences debris clearance and axonal regeneration in injured peripheral nerve. J Peripher Nerv Syst 2013; 17 Suppl 3:30-3. [PMID: 23279429 DOI: 10.1111/j.1529-8027.2012.00428.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
During 3 years, my research activities in Jack Griffin's laboratory focused on the influence of β-amyloid precursor protein cleaving enzyme 1 (BACE1) on the degeneration/regeneration of sciatic nerve of mice. Here, potential mechanisms of how BACE1 enzymatic activity influences these processes are discussed.
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Affiliation(s)
- Mohamed H Farah
- Department of Neurology, Johns Hopkins School of Medicine, 855 N. Wolfe St., Baltimore, MD 21205, USA.
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