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Hertzler JI, Teng J, Bernard AR, Stone MC, Kline HL, Mahata G, Kumar N, Rolls MM. Voltage-gated calcium channels act upstream of adenylyl cyclase Ac78C to promote timely initiation of dendrite regeneration. PLoS Genet 2024; 20:e1011388. [PMID: 39186815 DOI: 10.1371/journal.pgen.1011388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 08/06/2024] [Indexed: 08/28/2024] Open
Abstract
Most neurons are not replaced after injury and thus possess robust intrinsic mechanisms for repair after damage. Axon injury triggers a calcium wave, and calcium and cAMP can augment axon regeneration. In comparison to axon regeneration, dendrite regeneration is poorly understood. To test whether calcium and cAMP might also be involved in dendrite injury signaling, we tracked the responses of Drosophila dendritic arborization neurons to laser severing of axons and dendrites. We found that calcium and subsequently cAMP accumulate in the cell body after both dendrite and axon injury. Two voltage-gated calcium channels (VGCCs), L-Type and T-Type, are required for the calcium influx in response to dendrite injury and play a role in rapid initiation of dendrite regeneration. The AC8 family adenylyl cyclase, Ac78C, is required for cAMP production after dendrite injury and timely initiation of regeneration. Injury-induced cAMP production is sensitive to VGCC reduction, placing calcium upstream of cAMP generation. We propose that two VGCCs initiate global calcium influx in response to dendrite injury followed by production of cAMP by Ac78C. This signaling pathway promotes timely initiation of dendrite regrowth several hours after dendrite damage.
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Affiliation(s)
- J Ian Hertzler
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Jiajing Teng
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Annabelle R Bernard
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Michelle C Stone
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Hannah L Kline
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Gibarni Mahata
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Nitish Kumar
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Melissa M Rolls
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences The Pennsylvania State University, University Park, Pennsylvania, United States of America
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2
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Hilton BJ, Griffin JM, Fawcett JW, Bradke F. Neuronal maturation and axon regeneration: unfixing circuitry to enable repair. Nat Rev Neurosci 2024:10.1038/s41583-024-00849-3. [PMID: 39164450 DOI: 10.1038/s41583-024-00849-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2024] [Indexed: 08/22/2024]
Abstract
Mammalian neurons lose the ability to regenerate their central nervous system axons as they mature during embryonic or early postnatal development. Neuronal maturation requires a transformation from a situation in which neuronal components grow and assemble to one in which these components are fixed and involved in the machinery for effective information transmission and computation. To regenerate after injury, neurons need to overcome this fixed state to reactivate their growth programme. A variety of intracellular processes involved in initiating or sustaining neuronal maturation, including the regulation of gene expression, cytoskeletal restructuring and shifts in intracellular trafficking, have been shown to prevent axon regeneration. Understanding these processes will contribute to the identification of targets to promote repair after injury or disease.
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Affiliation(s)
- Brett J Hilton
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada.
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Jarred M Griffin
- Laboratory for Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - James W Fawcett
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK.
- Centre for Reconstructive Neuroscience, Institute for Experimental Medicine Czech Academy of Science (CAS), Prague, Czechia.
| | - Frank Bradke
- Laboratory for Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
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3
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Gordon T. Physiology of Nerve Regeneration: Key Factors Affecting Clinical Outcomes. Hand Clin 2024; 40:337-345. [PMID: 38972678 DOI: 10.1016/j.hcl.2024.03.001] [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] [Indexed: 07/09/2024]
Abstract
Functional recovery after peripheral nerve injuries is disappointing despite surgical advances in nerve repair. This review summarizes the relatively short window of opportunity for successful nerve regeneration due to the decline in the expression of growth-associated genes and in turn, the decline in regenerative capacity of the injured neurons and the support provided by the denervated Schwann cells, and the atrophy of denervated muscles. Brief, low-frequency electrical stimulation and post-injury exercise regimes ameliorate these deficits in animal models and patients, but the misdirection of regenerating nerve fibers compromises functional recovery and remains an important area of future research.
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Affiliation(s)
- Tessa Gordon
- Department of Surgery, University of Toronto, Toronto, Ontario M5G 1X8, Canada.
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4
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Hingorani S, Paniagua Soriano G, Sánchez Huertas C, Villalba Riquelme EM, López Mocholi E, Martínez Rojas B, Alastrué Agudo A, Dupraz S, Ferrer Montiel AV, Moreno Manzano V. Transplantation of dorsal root ganglia overexpressing the NaChBac sodium channel improves locomotion after complete SCI. Mol Ther 2024; 32:1739-1759. [PMID: 38556794 PMCID: PMC11184342 DOI: 10.1016/j.ymthe.2024.03.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/21/2024] [Accepted: 03/28/2024] [Indexed: 04/02/2024] Open
Abstract
Spinal cord injury (SCI) is a debilitating condition currently lacking treatment. Severe SCI causes the loss of most supraspinal inputs and neuronal activity caudal to the injury, which, coupled with the limited endogenous capacity for spontaneous regeneration, can lead to complete functional loss even in anatomically incomplete lesions. We hypothesized that transplantation of mature dorsal root ganglia (DRGs) genetically modified to express the NaChBac sodium channel could serve as a therapeutic option for functionally complete SCI. We found that NaChBac expression increased the intrinsic excitability of DRG neurons and promoted cell survival and neurotrophic factor secretion in vitro. Transplantation of NaChBac-expressing dissociated DRGs improved voluntary locomotion 7 weeks after injury compared to control groups. Animals transplanted with NaChBac-expressing DRGs also possessed higher tubulin-positive neuronal fiber and myelin preservation, although serotonergic descending fibers remained unaffected. We observed early preservation of the corticospinal tract 14 days after injury and transplantation, which was lost 7 weeks after injury. Nevertheless, transplantation of NaChBac-expressing DRGs increased the neuronal excitatory input by an increased number of VGLUT2 contacts immediately caudal to the injury. Our work suggests that the transplantation of NaChBac-expressing dissociated DRGs can rescue significant motor function, retaining an excitatory neuronal relay activity immediately caudal to injury.
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Affiliation(s)
- Sonia Hingorani
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Guillem Paniagua Soriano
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Carlos Sánchez Huertas
- Development and Assembly of Bilateral Neural Circuits Laboratory, Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Miguel Hernández, Avenida Santiago Ramon y Cajal, s/n, 03550 Sant Joan d'Alacant, Alicante, Spain
| | - Eva María Villalba Riquelme
- Biochemistry and Molecular Biology Department, Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche-IDiBE, Avenida de la Universidad, s/n, Edificio Torregaitán, 03202 Elche, Alicante, Spain
| | - Eric López Mocholi
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Beatriz Martínez Rojas
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Ana Alastrué Agudo
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Sebastián Dupraz
- Laboratory for Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany
| | - Antonio Vicente Ferrer Montiel
- Biochemistry and Molecular Biology Department, Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche-IDiBE, Avenida de la Universidad, s/n, Edificio Torregaitán, 03202 Elche, Alicante, Spain
| | - Victoria Moreno Manzano
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain.
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5
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Tharakan T, Kallogjeri D, Piccirillo JF. Clinical studies in COVID-related olfactory disorders: Review of an institutional experience. World J Otorhinolaryngol Head Neck Surg 2024; 10:129-136. [PMID: 38855285 PMCID: PMC11156682 DOI: 10.1002/wjo2.176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 02/20/2024] [Accepted: 03/08/2024] [Indexed: 06/11/2024] Open
Abstract
Objective To share a single institutional experience with clinical research on COVID-related olfactory dysfunction (OD). Data Source/Method Narrative review of published original data and ongoing clinical trials on COVID-related OD at Washington University from 2020 to 2023. Results There were three new diagnostic-/patient-reported outcome measures developed and tested. We report five clinical trials of interventions for COVID-related olfactory disorders: combined Visual-Olfactory Training (VOLT) with patient-preferred scents versus standard olfactory training (VOLT trial), oral gabapentin versus placebo (Gabapentin for the Relief of Acquired Chemosensory Experience trial), nasal theophylline irrigations versus placebo (Smell Changes and Efficacy of Nasal Theophylline trial), stellate ganglion block (single-arm), and mindfulness-based stress reduction (MBSR) versus lifestyle intervention (MBSR trial). Conclusions Initial intervention trials for COVID-related OD have shown potential for improving subjective and objective olfactory outcomes. However, there remains no gold standard treatment that definitively outperforms placebo in controlled trials. Therefore, continued investigation of novel therapeutic strategies for COVID-related OD is necessary to maximize olfactory outcomes for affected patients.
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Affiliation(s)
- Theresa Tharakan
- Department of Otolaryngology–Head and Neck Surgery, Clinical Outcomes Research Office, School of MedicineWashington University in St LouisSt LouisMissouriUSA
| | - Dorina Kallogjeri
- Department of Otolaryngology–Head and Neck Surgery, Clinical Outcomes Research Office, School of MedicineWashington University in St LouisSt LouisMissouriUSA
| | - Jay F. Piccirillo
- Department of Otolaryngology–Head and Neck Surgery, Clinical Outcomes Research Office, School of MedicineWashington University in St LouisSt LouisMissouriUSA
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Xu G, Zou X, Dong Y, Alhaskawi A, Zhou H, Ezzi SHA, Kota VG, Abdulla MHAH, Alenikova O, Abdalbary SA, Lu H. Advancements in autologous peripheral nerve transplantation care: a review of strategies and practices to facilitate recovery. Front Neurol 2024; 15:1330224. [PMID: 38523615 PMCID: PMC10959128 DOI: 10.3389/fneur.2024.1330224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 02/22/2024] [Indexed: 03/26/2024] Open
Abstract
Autologous peripheral nerve transplantation, a pioneering technique in nerve injury treatment, has demonstrated remarkable progress. We examine recent nursing strategies and methodologies tailored to various anatomical sites, highlighting their role in postoperative recovery enhancement. Encompassing brachial plexus, upper limb, and lower limb nerve transplantation care, this discussion underscores the importance of personalized rehabilitation plans, interdisciplinary collaboration, and innovative approaches like nerve electrical stimulation and nerve growth factor therapy. Moreover, the exploration extends to effective complication management and prevention strategies, encompassing infection control and pain management. Ultimately, the review concludes by emphasizing the advances achieved in autologous peripheral nerve transplantation care, showcasing the potential to optimize postoperative recovery through tailored and advanced practices.
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Affiliation(s)
- Guoying Xu
- Operating Theater, Shaoxing City Keqiao District Hospital of Traditional Chinese Medicine, Shaoxing, Zhejiang, China
| | - Xiaodi Zou
- Department of Orthopedics, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
| | - Yanzhao Dong
- Department of Orthopedics, The First Affiliated Hospital, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ahmad Alhaskawi
- Department of Orthopedics, The First Affiliated Hospital, Zhejiang University, Hangzhou, Zhejiang, China
| | - Haiying Zhou
- Faculty of Medicine, School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | | | | | | | - Olga Alenikova
- Department of Neurology, Republican Research and Clinical Center of Neurology and Neurosurgery, Minsk, Belarus
| | - Sahar Ahmed Abdalbary
- Department of Orthopedic Physical Therapy, Faculty of Physical Therapy, Nahda University in Beni Suef, Beni Suef, Egypt
| | - Hui Lu
- Operating Theater, Shaoxing City Keqiao District Hospital of Traditional Chinese Medicine, Shaoxing, Zhejiang, China
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7
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Gordon T. Brief Electrical Stimulation Promotes Recovery after Surgical Repair of Injured Peripheral Nerves. Int J Mol Sci 2024; 25:665. [PMID: 38203836 PMCID: PMC10779324 DOI: 10.3390/ijms25010665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 12/07/2023] [Accepted: 12/08/2023] [Indexed: 01/12/2024] Open
Abstract
Injured peripheral nerves regenerate their axons in contrast to those in the central nervous system. Yet, functional recovery after surgical repair is often disappointing. The basis for poor recovery is progressive deterioration with time and distance of the growth capacity of the neurons that lose their contact with targets (chronic axotomy) and the growth support of the chronically denervated Schwann cells (SC) in the distal nerve stumps. Nonetheless, chronically denervated atrophic muscle retains the capacity for reinnervation. Declining electrical activity of motoneurons accompanies the progressive fall in axotomized neuronal and denervated SC expression of regeneration-associated-genes and declining regenerative success. Reduced motoneuronal activity is due to the withdrawal of synaptic contacts from the soma. Exogenous neurotrophic factors that promote nerve regeneration can replace the endogenous factors whose expression declines with time. But the profuse axonal outgrowth they provoke and the difficulties in their delivery hinder their efficacy. Brief (1 h) low-frequency (20 Hz) electrical stimulation (ES) proximal to the injury site promotes the expression of endogenous growth factors and, in turn, dramatically accelerates axon outgrowth and target reinnervation. The latter ES effect has been demonstrated in both rats and humans. A conditioning ES of intact nerve days prior to nerve injury increases axonal outgrowth and regeneration rate. Thereby, this form of ES is amenable for nerve transfer surgeries and end-to-side neurorrhaphies. However, additional surgery for applying the required electrodes may be a hurdle. ES is applicable in all surgeries with excellent outcomes.
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Affiliation(s)
- Tessa Gordon
- Division of Reconstructive Surgery, Department of Surgery, University of Toronto, Toronto, ON M4G 1X8, Canada
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8
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UENO YUJI. Mechanism of Post-stroke Axonal Outgrowth and Functional Recovery. JUNTENDO IJI ZASSHI = JUNTENDO MEDICAL JOURNAL 2023; 69:364-369. [PMID: 38845728 PMCID: PMC10984353 DOI: 10.14789/jmj.jmj23-0025-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 08/21/2023] [Indexed: 06/09/2024]
Abstract
Axonal outgrowth after stroke plays an important role in tissue repair and is critical for functional recovery. In the peri-infarct area of a rat middle cerebral artery occlusion model, we found that the axons and dendrites that had fallen off in the acute phase of stroke (7 days) were regenerated in the chronic phase of stroke (56 days). In vitro, we showed that phosphatase tensin homolog deleted on chromosome 10/Akt/Glycogen synthase kinase 3β signaling is implicated in postischemic axonal regeneration. In a rat model of chronic cerebral hypoperfusion, oral administration of L-carnitine induced axonal and oligodendrocyte regeneration in the cerebral white matter, resulting in myelin thickening, and it improved cognitive impairment in rats with chronic cerebral ischemia. Recently, it has been shown that exosomes enhanced functional recovery after stroke. Exosome treatment has less tumorigenicity, does not occlude the microvascular system, has low immunogenicity, and does not require a host immune response compared to conventional cell therapy. Several studies demonstrated specific microRNA in exosomes, which regulated signaling pathways related to neurogenesis after stroke. Collectively, there are various mechanisms of axonal regeneration and functional recovery after stroke, and it is expected that new therapeutic agents for stroke with the aim of axonal regeneration will be developed and used in real-world clinical practice in the future.
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Affiliation(s)
- YUJI UENO
- Corresponding author: Yuji Ueno, Department of Neurology, University of Yamanashi, 1110 Shimokato, Chuo-city, Yamanashi 409-3898, Japan, TEL/FAX: +81-55-273-9896 E-mail: ,
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9
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Gao J, Khang MK, Liao Z, Webb K, Detloff MR, Lee JS. Rolipram-loaded PgP nanoparticle reduces secondary injury and enhances motor function recovery in a rat moderate contusion SCI model. NANOMEDICINE : NANOTECHNOLOGY, BIOLOGY, AND MEDICINE 2023; 53:102702. [PMID: 37574117 DOI: 10.1016/j.nano.2023.102702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 07/30/2023] [Accepted: 08/02/2023] [Indexed: 08/15/2023]
Abstract
Spinal cord injury (SCI) results in immediate axonal damage and cell death, as well as a prolonged secondary injury consist of a cascade of pathophysiological processes. One important aspect of secondary injury is activation of phosphodiesterase 4 (PDE4) that leads to reduce cAMP levels in the injured spinal cord. We have developed an amphiphilic copolymer, poly (lactide-co-glycolide)-graft-polyethylenimine (PgP) that can deliver Rolipram, the PDE4 inhibitor. The objective of this work was to investigate the effect of rolipram loaded PgP (Rm-PgP) on secondary injury and motor functional recovery in a rat moderate contusion SCI model. We observed that Rm-PgP can increase cAMP level at the lesion site, and reduce secondary injury such as the inflammatory response by macrophages/microglia, astrogliosis by activated astrocytes and apoptosis as well as improve neuronal survival at 4 weeks post-injury (WPI). We also observed that Rm-PgP can improve motor functional recovery after SCI over 4 WPI.
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Affiliation(s)
- Jun Gao
- Drug Design Delivery and Development (4D) Laboratory, Department of Bioengineering, Clemson University, Clemson, SC, USA
| | - Min Kyung Khang
- Drug Design Delivery and Development (4D) Laboratory, Department of Bioengineering, Clemson University, Clemson, SC, USA
| | - Zhen Liao
- Drug Design Delivery and Development (4D) Laboratory, Department of Bioengineering, Clemson University, Clemson, SC, USA.
| | - Ken Webb
- MicroEnvironmental Laboratory, Department of Bioengineering, Clemson University, Clemson, SC, USA.
| | - Megan Ryan Detloff
- Department of Neurobiology & Anatomy, Marion Murray Spinal Cord Research Center, College of Medicine, Drexel University, Philadelphia, PA 19129, USA.
| | - Jeoung Soo Lee
- Drug Design Delivery and Development (4D) Laboratory, Department of Bioengineering, Clemson University, Clemson, SC, USA.
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10
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Halawani D, Wang Y, Ramakrishnan A, Estill M, He X, Shen L, Friedel RH, Zou H. Circadian clock regulator Bmal1 gates axon regeneration via Tet3 epigenetics in mouse sensory neurons. Nat Commun 2023; 14:5165. [PMID: 37620297 PMCID: PMC10449865 DOI: 10.1038/s41467-023-40816-7] [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: 10/25/2022] [Accepted: 08/11/2023] [Indexed: 08/26/2023] Open
Abstract
Axon regeneration of dorsal root ganglia (DRG) neurons after peripheral axotomy involves reconfiguration of gene regulatory circuits to establish regenerative gene programs. However, the underlying mechanisms remain unclear. Here, through an unbiased survey, we show that the binding motif of Bmal1, a central transcription factor of the circadian clock, is enriched in differentially hydroxymethylated regions (DhMRs) of mouse DRG after peripheral lesion. By applying conditional deletion of Bmal1 in neurons, in vitro and in vivo neurite outgrowth assays, as well as transcriptomic profiling, we demonstrate that Bmal1 inhibits axon regeneration, in part through a functional link with the epigenetic factor Tet3. Mechanistically, we reveal that Bmal1 acts as a gatekeeper of neuroepigenetic responses to axonal injury by limiting Tet3 expression and restricting 5hmC modifications. Bmal1-regulated genes not only concern axon growth, but also stress responses and energy homeostasis. Furthermore, we uncover an epigenetic rhythm of diurnal oscillation of Tet3 and 5hmC levels in DRG neurons, corresponding to time-of-day effect on axon growth potential. Collectively, our studies demonstrate that targeting Bmal1 enhances axon regeneration.
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Affiliation(s)
- Dalia Halawani
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Yiqun Wang
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, Shaanxi, China
| | - Aarthi Ramakrishnan
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Molly Estill
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Xijing He
- Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, Shaanxi, China
- Department of Orthopedics, Xi'an International Medical Center Hospital, Xi'an, China
| | - Li Shen
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Roland H Friedel
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Hongyan Zou
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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11
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Grooms NW, Fitzgerald MQ, Zuckerman B, Ureña SE, Weinberger LS, Chung SH. Expression of thioredoxin-1 in the ASJ neuron corresponds with and enhances intrinsic regenerative capacity under lesion conditioning in C. elegans. FEBS Lett 2023; 597:1880-1893. [PMID: 37300530 PMCID: PMC10526644 DOI: 10.1002/1873-3468.14684] [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: 05/10/2023] [Revised: 06/02/2023] [Accepted: 05/17/2023] [Indexed: 06/12/2023]
Abstract
A conditioning lesion of the peripheral sensory axon triggers robust central axon regeneration in mammals. We trigger conditioned regeneration in the Caenorhabditis elegans ASJ neuron by laser surgery or genetic disruption of sensory pathways. Conditioning upregulates thioredoxin-1 (trx-1) expression, as indicated by trx-1 promoter-driven expression of green fluorescent protein and fluorescence in situ hybridization (FISH), suggesting trx-1 levels and associated fluorescence indicate regenerative capacity. The redox activity of trx-1 functionally enhances conditioned regeneration, but both redox-dependent and -independent activity inhibit non-conditioned regeneration. Six strains isolated in a forward genetic screen for reduced fluorescence, which suggests diminished regenerative potential, also show reduced axon outgrowth. We demonstrate an association between trx-1 expression and the conditioned state that we leverage to rapidly assess regenerative capacity.
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Affiliation(s)
- Noa W.F. Grooms
- Department of Bioengineering, Northeastern University, Boston, Massachusetts, 02115, USA
| | - Michael Q. Fitzgerald
- Department of Bioengineering, Northeastern University, Boston, Massachusetts, 02115, USA
| | - Binyamin Zuckerman
- Gladstone/UCSF Center for Cell Circuitry, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Samuel E. Ureña
- Department of Bioengineering, Northeastern University, Boston, Massachusetts, 02115, USA
| | - Leor S. Weinberger
- Gladstone/UCSF Center for Cell Circuitry, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Samuel H. Chung
- Department of Bioengineering, Northeastern University, Boston, Massachusetts, 02115, USA
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12
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Sousa CS, Lima R, Cibrão JR, Gomes ED, Fernandes LS, Pinho TS, Silva D, Campos J, Salgado AJ, Silva NA. Pre-Clinical Assessment of Roflumilast Therapy in a Thoracic Model of Spinal Cord Injury. Pharmaceutics 2023; 15:pharmaceutics15051556. [PMID: 37242797 DOI: 10.3390/pharmaceutics15051556] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 05/14/2023] [Accepted: 05/17/2023] [Indexed: 05/28/2023] Open
Abstract
The failure of axons to regenerate after a spinal cord injury (SCI) remains one of the greatest challenges in neuroscience. The initial mechanical trauma is followed by a secondary injury cascade, creating a hostile microenvironment, which not only is not permissive to regeneration but also leads to further damage. One of the most promising approaches for promoting axonal regeneration is to maintain the levels of cyclic adenosine monophosphate (cAMP), specifically by a phosphodiesterase-4 (PDE4) inhibitor expressed in neural tissues. Therefore, in our study, we evaluated the therapeutic effect of an FDA-approved PDE4 inhibitor, Roflumilast (Rof), in a thoracic contusion rat model. Results indicate that the treatment was effective in promoting functional recovery. Rof-treated animals showed improvements in both gross and fine motor function. Eight weeks post-injury, the animals significantly recovered by achieving occasional weight-supported plantar steps. Histological assessment revealed a significant decrease in cavity size, less reactive microglia, as well as higher axonal regeneration in treated animals. Molecular analysis revealed that IL-10 and IL-13 levels, as well as VEGF, were increased in the serum of Rof-treated animals. Overall, Roflumilast promotes functional recovery and supports neuroregeneration in a severe thoracic contusion injury model and may be important in SCI treatment.
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Affiliation(s)
- Carla S Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's Associate Lab, PT Government Associated Lab, 4805-017 Guimarães, Portugal
- Department of Neurosurgery, Hospital Garcia de Orta, 2805-267 Almada, Portugal
| | - Rui Lima
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's Associate Lab, PT Government Associated Lab, 4805-017 Guimarães, Portugal
| | - Jorge R Cibrão
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's Associate Lab, PT Government Associated Lab, 4805-017 Guimarães, Portugal
| | - Eduardo D Gomes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's Associate Lab, PT Government Associated Lab, 4805-017 Guimarães, Portugal
| | - Luís S Fernandes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's Associate Lab, PT Government Associated Lab, 4805-017 Guimarães, Portugal
| | - Tiffany S Pinho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's Associate Lab, PT Government Associated Lab, 4805-017 Guimarães, Portugal
| | - Deolinda Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's Associate Lab, PT Government Associated Lab, 4805-017 Guimarães, Portugal
| | - Jonas Campos
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's Associate Lab, PT Government Associated Lab, 4805-017 Guimarães, Portugal
| | - António J Salgado
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's Associate Lab, PT Government Associated Lab, 4805-017 Guimarães, Portugal
| | - Nuno A Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's Associate Lab, PT Government Associated Lab, 4805-017 Guimarães, Portugal
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13
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Mussen F, Broeckhoven JV, Hellings N, Schepers M, Vanmierlo T. Unleashing Spinal Cord Repair: The Role of cAMP-Specific PDE Inhibition in Attenuating Neuroinflammation and Boosting Regeneration after Traumatic Spinal Cord Injury. Int J Mol Sci 2023; 24:ijms24098135. [PMID: 37175842 PMCID: PMC10179671 DOI: 10.3390/ijms24098135] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 04/27/2023] [Accepted: 04/29/2023] [Indexed: 05/15/2023] Open
Abstract
Traumatic spinal cord injury (SCI) is characterized by severe neuroinflammation and hampered neuroregeneration, which often leads to permanent neurological deficits. Current therapies include decompression surgery, rehabilitation, and in some instances, the use of corticosteroids. However, the golden standard of corticosteroids still achieves minimal improvements in functional outcomes. Therefore, new strategies tackling the initial inflammatory reactions and stimulating endogenous repair in later stages are crucial to achieving functional repair in SCI patients. Cyclic adenosine monophosphate (cAMP) is an important second messenger in the central nervous system (CNS) that modulates these processes. A sustained drop in cAMP levels is observed during SCI, and elevating cAMP is associated with improved functional outcomes in experimental models. cAMP is regulated in a spatiotemporal manner by its hydrolyzing enzyme phosphodiesterase (PDE). Growing evidence suggests that inhibition of cAMP-specific PDEs (PDE4, PDE7, and PDE8) is an important strategy to orchestrate neuroinflammation and regeneration in the CNS. Therefore, this review focuses on the current evidence related to the immunomodulatory and neuroregenerative role of cAMP-specific PDE inhibition in the SCI pathophysiology.
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Affiliation(s)
- Femke Mussen
- Department of Neuroscience, Biomedical Research Institute BIOMED, Hasselt University, 3590 Diepenbeek, Belgium
- University MS Center (UMSC) Hasselt-Pelt, Hasselt University, 3500 Hasselt, Belgium
| | - Jana Van Broeckhoven
- University MS Center (UMSC) Hasselt-Pelt, Hasselt University, 3500 Hasselt, Belgium
- Department of Immunology and Infection, Biomedical Research Institute BIOMED, Hasselt University, 3590 Diepenbeek, Belgium
| | - Niels Hellings
- University MS Center (UMSC) Hasselt-Pelt, Hasselt University, 3500 Hasselt, Belgium
- Department of Immunology and Infection, Biomedical Research Institute BIOMED, Hasselt University, 3590 Diepenbeek, Belgium
| | - Melissa Schepers
- Department of Neuroscience, Biomedical Research Institute BIOMED, Hasselt University, 3590 Diepenbeek, Belgium
- University MS Center (UMSC) Hasselt-Pelt, Hasselt University, 3500 Hasselt, Belgium
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, 6229ER Maastricht, The Netherlands
| | - Tim Vanmierlo
- Department of Neuroscience, Biomedical Research Institute BIOMED, Hasselt University, 3590 Diepenbeek, Belgium
- University MS Center (UMSC) Hasselt-Pelt, Hasselt University, 3500 Hasselt, Belgium
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, 6229ER Maastricht, The Netherlands
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14
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Zheng B, Tuszynski MH. Regulation of axonal regeneration after mammalian spinal cord injury. Nat Rev Mol Cell Biol 2023; 24:396-413. [PMID: 36604586 DOI: 10.1038/s41580-022-00562-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 57.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2022] [Indexed: 01/06/2023]
Abstract
One hundred years ago, Ramón y Cajal, considered by many as the founder of modern neuroscience, stated that neurons of the adult central nervous system (CNS) are incapable of regenerating. Yet, recent years have seen a tremendous expansion of knowledge in the molecular control of axon regeneration after CNS injury. We now understand that regeneration in the adult CNS is limited by (1) a failure to form cellular or molecular substrates for axon attachment and elongation through the lesion site; (2) environmental factors, including inhibitors of axon growth associated with myelin and the extracellular matrix; (3) astrocyte responses, which can both limit and support axon growth; and (4) intraneuronal mechanisms controlling the establishment of an active cellular growth programme. We discuss these topics together with newly emerging hypotheses, including the surprising finding from transcriptomic analyses of the corticospinal system in mice that neurons revert to an embryonic state after spinal cord injury, which can be sustained to promote regeneration with neural stem cell transplantation. These gains in knowledge are steadily advancing efforts to develop effective treatment strategies for spinal cord injury in humans.
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Affiliation(s)
- Binhai Zheng
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA. .,VA San Diego Research Service, San Diego, CA, USA.
| | - Mark H Tuszynski
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA. .,VA San Diego Research Service, San Diego, CA, USA.
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15
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Omura T. Editorial: Axonal growth in normal and pathological conditions. Front Mol Neurosci 2022; 15:1107999. [PMID: 36583083 PMCID: PMC9792978 DOI: 10.3389/fnmol.2022.1107999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 11/28/2022] [Indexed: 12/15/2022] Open
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16
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Juckett L, Saffari TM, Ormseth B, Senger JL, Moore AM. The Effect of Electrical Stimulation on Nerve Regeneration Following Peripheral Nerve Injury. Biomolecules 2022; 12:biom12121856. [PMID: 36551285 PMCID: PMC9775635 DOI: 10.3390/biom12121856] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/02/2022] [Accepted: 12/07/2022] [Indexed: 12/15/2022] Open
Abstract
Peripheral nerve injuries (PNI) are common and often result in lifelong disability. The peripheral nervous system has an inherent ability to regenerate following injury, yet complete functional recovery is rare. Despite advances in the diagnosis and repair of PNIs, many patients suffer from chronic pain, and sensory and motor dysfunction. One promising surgical adjunct is the application of intraoperative electrical stimulation (ES) to peripheral nerves. ES acts through second messenger cyclic AMP to augment the intrinsic molecular pathways of regeneration. Decades of animal studies have demonstrated that 20 Hz ES delivered post-surgically accelerates axonal outgrowth and end organ reinnervation. This work has been translated clinically in a series of randomized clinical trials, which suggest that ES can be used as an efficacious therapy to improve patient outcomes following PNIs. The aim of this review is to discuss the cellular physiology and the limitations of regeneration after peripheral nerve injuries. The proposed mechanisms of ES protocols and how they facilitate nerve regeneration depending on timing of administration are outlined. Finally, future directions of research that may provide new perspectives on the optimal delivery of ES following PNI are discussed.
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17
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Taylor MJ, Thompson AM, Alhajlah S, Tuxworth RI, Ahmed Z. Inhibition of Chk2 promotes neuroprotection, axon regeneration, and functional recovery after CNS injury. SCIENCE ADVANCES 2022; 8:eabq2611. [PMID: 36103534 PMCID: PMC9473583 DOI: 10.1126/sciadv.abq2611] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 07/29/2022] [Indexed: 06/15/2023]
Abstract
DNA double-strand breaks occur in many acute and long-term neurological conditions, including neurodegeneration, neurotrauma, and stroke. Nonrepaired breaks chronically activate the DNA damage response in neurons, leading to neural dysfunction and apoptosis. Here, we show that targeting of the central ATM-Chk2 pathway regulating the response to double-strand breaks slows neural decline in Drosophila models of chronic neurodegeneration. Inhibitors of ATM-Chk2, but not the parallel ATR-Chk1 pathway, also promote marked, functional recovery after acute central nervous system injury in rats, suggesting that inhibiting nonhomologous end-joining rather than homologous recombination is crucial for neuroprotection. We demonstrate that the Chk2 inhibitor, prexasertib, which has been evaluated in phase 2 clinical trials for cancer, has potent neuroprotective effects and represents a new treatment option to promote functional recovery after spinal cord or optic nerve injury.
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Affiliation(s)
- Matthew J. Taylor
- Institute of Cancer and Genomic Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Adam M. Thompson
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Sharif Alhajlah
- Applied Medical Science College, Shaqra University, Addawadmi, Riyadh, Saudi Arabia
| | - Richard I. Tuxworth
- Institute of Cancer and Genomic Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Zubair Ahmed
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
- Centre for Trauma Sciences Research, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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18
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NPC transplantation rescues sci-driven cAMP/EPAC2 alterations, leading to neuroprotection and microglial modulation. Cell Mol Life Sci 2022; 79:455. [PMID: 35904607 PMCID: PMC9338125 DOI: 10.1007/s00018-022-04494-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 07/07/2022] [Accepted: 07/17/2022] [Indexed: 11/17/2022]
Abstract
Neural progenitor cell (NPC) transplantation represents a promising treatment strategy for spinal cord injury (SCI); however, the underlying therapeutic mechanisms remain incompletely understood. We demonstrate that severe spinal contusion in adult rats causes transcriptional dysregulation, which persists from early subacute to chronic stages of SCI and affects nearly 20,000 genes in total tissue extracts. Functional analysis of this dysregulated transcriptome reveals the significant downregulation of cAMP signalling components immediately after SCI, involving genes such as EPAC2 (exchange protein directly activated by cAMP), PKA, BDNF, and CAMKK2. The ectopic transplantation of spinal cord-derived NPCs at acute or subacute stages of SCI induces a significant transcriptional impact in spinal tissue, as evidenced by the normalized expression of a large proportion of SCI-affected genes. The transcriptional modulation pattern driven by NPC transplantation includes the rescued expression of cAMP signalling genes, including EPAC2. We also explore how the sustained in vivo inhibition of EPAC2 downstream signalling via the intrathecal administration of ESI-05 for 1 week impacts therapeutic mechanisms involved in the NPC-mediated treatment of SCI. NPC transplantation in SCI rats in the presence and absence of ESI-05 administration prompts increased rostral cAMP levels; however, NPC and ESI-05 treated animals exhibit a significant reduction in EPAC2 mRNA levels compared to animals receiving only NPCs treatment. Compared with transplanted animals, NPCs + ESI-05 treatment increases the scar area (as shown by GFAP staining), polarizes microglia into an inflammatory phenotype, and increases the magnitude of the gap between NeuN + cells across the lesion. Overall, our results indicate that the NPC-associated therapeutic mechanisms in the context of SCI involve the cAMP pathway, which reduces inflammation and provides a more neuropermissive environment through an EPAC2-dependent mechanism.
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19
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Gupta S, Lee JJ, Perrin A, Khan A, Smith HJ, Farrell N, Kallogjeri D, Piccirillo JF. Efficacy and Safety of Saline Nasal Irrigation Plus Theophylline for Treatment of COVID-19-Related Olfactory Dysfunction: The SCENT2 Phase 2 Randomized Clinical Trial. JAMA Otolaryngol Head Neck Surg 2022; 148:830-837. [PMID: 35797024 DOI: 10.1001/jamaoto.2022.1573] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Importance Recent studies suggest that theophylline added to saline nasal irrigation (SNI) can be an effective treatment for postviral olfactory dysfunction (OD), a growing public health concern during the COVID-19 pandemic. Objective To evaluate the efficacy and safety of theophylline added to SNI compared with placebo for COVID-19-related OD. Design, Setting, and Participants This triple-blinded, placebo-controlled, phase 2 randomized clinical trial was conducted virtually between March 15 and August 31, 2021. Adults residing in Missouri or Illinois were recruited during this time period if they had OD persisting for 3 to 12 months following suspected COVID-19 infection. Data analysis was conducted from October to December 2021. Interventions Saline sinus rinse kits and bottles of identical-appearing capsules with either 400 mg of theophylline (treatment) or 500 mg of lactose powder (control) were mailed to consenting study participants. Participants were instructed to dissolve the capsule contents into the saline rinse and use the solution to irrigate their nasal cavities in the morning and at night for 6 weeks. Main Outcomes and Measures The primary outcome was the difference in the rate of responders between the treatment and the control arms, defined as a response of at least slightly better improvement in the Clinical Global Impression-Improvement scale posttreatment. Secondary outcome measures included changes in the University of Pennsylvania Smell Identification Test (UPSIT), the Questionnaire for Olfactory Disorders, the 36-Item Short Form Health Survey on general health, and COVID-19-related questions. Results A total of 51 participants were enrolled in the study; the mean (SD) age was 46.0 (13.1) years, and 36 (71%) participants were women. Participants were randomized to SNI with theophylline (n = 26) or to SNI with placebo (n = 25). Forty-five participants completed the study. At the end of treatment, 13 (59%) participants in the theophylline arm reported at least slight improvement in the Clinical Global Impression-Improvement scale (responders) compared with 10 (43%) in the placebo arm (absolute difference, 15.6%; 95% CI, -13.2% to 44.5%). The median difference for the UPSIT change between baseline and 6 weeks was 3.0 (95% CI, -1.0 to 7.0) for participants in the theophylline arm and 0.0 (95% CI, -2.0 to 6.0) for participants in the placebo arm. Mixed-model analysis revealed that the change in UPSIT scores through study assessments was not statistically significantly different between the 2 study arms. Eleven (50%) participants in the theophylline arm and 6 (26%) in the placebo arm had a change of 4 or more points in UPSIT scores from baseline to 6 weeks. The difference in the rate of responders as measured by the UPSIT was 24% (95% CI, -4% to 52%) in favor of theophylline. Conclusions and Relevance This randomized clinical trial suggests that the clinical benefit of theophylline nasal irrigations on olfaction in participants with COVID-19-related OD is inconclusive, though suggested by subjective assessments. Larger studies are warranted to investigate the efficacy of this treatment more fully. Trial Registration ClinicalTrials.gov Identifier: NCT04789499.
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Affiliation(s)
- Shruti Gupta
- Clinical Outcomes Research Office, Department of Otolaryngology-Head & Neck Surgery, Washington University School of Medicine in St Louis, St Louis, Missouri.,Medical College of Georgia, Augusta University, Augusta
| | - Jake J Lee
- Clinical Outcomes Research Office, Department of Otolaryngology-Head & Neck Surgery, Washington University School of Medicine in St Louis, St Louis, Missouri
| | - Amber Perrin
- Clinical Outcomes Research Office, Department of Otolaryngology-Head & Neck Surgery, Washington University School of Medicine in St Louis, St Louis, Missouri
| | - Amish Khan
- Washington University School of Medicine in St Louis, St Louis, Missouri
| | | | - Nyssa Farrell
- Division of Rhinology, Department of Otolaryngology-Head & Neck Surgery, Washington University School of Medicine in St Louis, St Louis, Missouri
| | - Dorina Kallogjeri
- Clinical Outcomes Research Office, Department of Otolaryngology-Head & Neck Surgery, Washington University School of Medicine in St Louis, St Louis, Missouri
| | - Jay F Piccirillo
- Clinical Outcomes Research Office, Department of Otolaryngology-Head & Neck Surgery, Washington University School of Medicine in St Louis, St Louis, Missouri
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20
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Cooke P, Janowitz H, Dougherty SE. Neuronal Redevelopment and the Regeneration of Neuromodulatory Axons in the Adult Mammalian Central Nervous System. Front Cell Neurosci 2022; 16:872501. [PMID: 35530177 PMCID: PMC9074815 DOI: 10.3389/fncel.2022.872501] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 03/24/2022] [Indexed: 01/09/2023] Open
Abstract
One reason that many central nervous system injuries, including those arising from traumatic brain injury, spinal cord injury, and stroke, have limited recovery of function is that neurons within the adult mammalian CNS lack the ability to regenerate their axons following trauma. This stands in contrast to neurons of the adult mammalian peripheral nervous system (PNS). New evidence, provided by single-cell expression profiling, suggests that, following injury, both mammalian central and peripheral neurons can revert to an embryonic-like growth state which is permissive for axon regeneration. This “redevelopment” strategy could both facilitate a damage response necessary to isolate and repair the acute damage from injury and provide the intracellular machinery necessary for axon regrowth. Interestingly, serotonin neurons of the rostral group of raphe nuclei, which project their axons into the forebrain, display a robust ability to regenerate their axons unaided, counter to the widely held view that CNS axons cannot regenerate without experimental intervention after injury. Furthermore, initial evidence suggests that norepinephrine neurons within the locus coeruleus possess similar regenerative abilities. Several morphological characteristics of serotonin axon regeneration in adult mammals, observable using longitudinal in vivo imaging, are distinct from the known characteristics of unaided peripheral nerve regeneration, or of the regeneration seen in the spinal cord and optic nerve that occurs with experimental intervention. These results suggest that there is an alternative CNS program for axon regeneration that likely differs from that displayed by the PNS.
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Affiliation(s)
- Patrick Cooke
- Linden Lab, Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Haley Janowitz
- Linden Lab, Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Sarah E Dougherty
- Linden Lab, Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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21
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Lee JJ, Peterson AM, Kallogjeri D, Jiramongkolchai P, Kukuljan S, Schneider JS, Klatt-Cromwell CN, Drescher AJ, Brunworth JD, Piccirillo JF. Smell Changes and Efficacy of Nasal Theophylline (SCENT) irrigation: A randomized controlled trial for treatment of post-viral olfactory dysfunction. Am J Otolaryngol 2022; 43:103299. [PMID: 34894449 PMCID: PMC9057210 DOI: 10.1016/j.amjoto.2021.103299] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/28/2021] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To evaluate the efficacy and safety of intranasal theophylline saline irrigation on olfactory recovery in patients with post-viral olfactory dysfunction (PVOD). METHODS Between May 2019 and April 2020, we conducted a double-blinded, placebo-controlled randomized clinical trial of adults with 6-36 months of PVOD. Patients were randomized to nasal theophylline saline irrigation or placebo saline irrigation twice a day for 6 weeks. The primary outcome was the Global Rating of Smell Change. Secondary outcomes were changes in the University of Pennsylvania Smell Identification Test (UPSIT) and Questionnaire of Olfactory Disorders-Negative Statements (QOD-NS). RESULTS Twenty-two patients (n = 12, theophylline; n = 10, placebo) completed the study. Slightly more patients in the theophylline group (33%) reported improved smell compared to the placebo group (30%, difference 3.3%, 95% CI -35.6% to 42.3%). The median differences in pre- and post-treatment UPSIT and QOD-NS change between the two groups were 1 (95% CI -3 to 5) and -10 (95% CI -15 to -4), respectively in favor of theophylline. Three patients receiving theophylline and 2 receiving placebo had clinically meaningful improvements on the UPSIT (difference 5%, 95% CI -30% to 40%). There were no adverse events, and serum theophylline levels were undetectable in 10/10 patients. CONCLUSIONS While safe, there were no clinically meaningful differences in olfactory change between the two groups except for olfaction-related quality of life, which was better with theophylline. The imprecise estimates suggest future trials will need substantially larger sample sizes or treatment modifications, such as increasing the theophylline dose, to observe larger treatment effects.
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Affiliation(s)
- Jake J Lee
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO, USA.
| | - Andrew M Peterson
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO, USA; University of Missouri Kansas City School of Medicine, Kansas City, MO, USA
| | - Dorina Kallogjeri
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO, USA
| | - Pawina Jiramongkolchai
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO, USA
| | - Sara Kukuljan
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO, USA
| | - John S Schneider
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO, USA
| | - Cristine N Klatt-Cromwell
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO, USA
| | - Andrew J Drescher
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO, USA
| | - Joseph D Brunworth
- Department of Otolaryngology-Head and Neck Surgery, Saint Louis University School of Medicine, St. Louis, MO, USA
| | - Jay F Piccirillo
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO, USA
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22
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Zhou G, Wang Z, Han S, Chen X, Li Z, Hu X, Li Y, Gao J. Multifaceted Roles of cAMP Signaling in the Repair Process of Spinal Cord Injury and Related Combination Treatments. Front Mol Neurosci 2022; 15:808510. [PMID: 35283731 PMCID: PMC8904388 DOI: 10.3389/fnmol.2022.808510] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 01/26/2022] [Indexed: 01/03/2023] Open
Abstract
Spinal cord injury (SCI) results in multiple pathophysiological processes, including blood–spinal cord barrier disruption, hemorrhage/ischemia, oxidative stress, neuroinflammation, scar formation, and demyelination. These responses eventually lead to severe tissue destruction and an inhibitory environment for neural regeneration.cAMP signaling is vital for neurite outgrowth and axonal guidance. Stimulating intracellular cAMP activity significantly promotes neuronal survival and axonal regrowth after SCI.However, neuronal cAMP levels in adult CNS are relatively low and will further decrease after injury. Targeting cAMP signaling has become a promising strategy for neural regeneration over the past two decades. Furthermore, studies have revealed that cAMP signaling is involved in the regulation of glial cell function in the microenvironment of SCI, including macrophages/microglia, reactive astrocytes, and oligodendrocytes. cAMP-elevating agents in the post-injury milieu increase the cAMP levels in both neurons and glial cells and facilitate injury repair through the interplay between neurons and glial cells and ultimately contribute to better morphological and functional outcomes. In recent years, combination treatments associated with cAMP signaling have been shown to exert synergistic effects on the recovery of SCI. Agents carried by nanoparticles exhibit increased water solubility and capacity to cross the blood–spinal cord barrier. Implanted bioscaffolds and injected hydrogels are potential carriers to release agents locally to avoid systemic side effects. Cell transplantation may provide permissive matrices to synergize with the cAMP-enhanced growth capacity of neurons. cAMP can also induce the oriented differentiation of transplanted neural stem/progenitor cells into neurons and increase the survival rate of cell grafts. Emerging progress focused on cAMP compartmentation provides researchers with new perspectives to understand the complexity of downstream signaling, which may facilitate the clinical translation of strategies targeting cAMP signaling for SCI repair.
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Affiliation(s)
- Gang Zhou
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Zhiyan Wang
- Plastic Surgery Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Shiyuan Han
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xiaokun Chen
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Zhimin Li
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xianghui Hu
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yongning Li
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- Department of International Medical Service, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Jun Gao
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- *Correspondence: Jun Gao
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23
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Lu J, Wang X, Wu A, Cao Y, Dai X, Liang Y, Li X. Ginsenosides in central nervous system diseases: Pharmacological actions, mechanisms, and therapeutics. Phytother Res 2022; 36:1523-1544. [PMID: 35084783 DOI: 10.1002/ptr.7395] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 01/04/2022] [Accepted: 01/08/2022] [Indexed: 12/11/2022]
Abstract
The nervous system is one of the most complex physiological systems, and central nervous system diseases (CNSDs) are serious diseases that affect human health. Ginseng (Panax L.), the root of Panax species, are famous Chinese herbs that have been used for various diseases in China, Japan, and Korea since ancient times, and remain a popular natural medicine used worldwide in modern times. Ginsenosides are the main active components of ginseng, and increasing evidence has demonstrated that ginsenosides can prevent CNSDs, including neurodegenerative diseases, memory and cognitive impairment, cerebral ischemia injury, depression, brain glioma, multiple sclerosis, which has been confirmed in numerous studies. Therefore, this review summarizes the potential pathways by which ginsenosides affect the pathogenesis of CNSDs mainly including antioxidant effects, anti-inflammatory effects, anti-apoptotic effects, and nerve protection, which provides novel ideas for the treatment of CNSDs.
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Affiliation(s)
- Jing Lu
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Xian Wang
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Anxin Wu
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yi Cao
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Xiaolin Dai
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Youdan Liang
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Xiaofang Li
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
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24
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Varadarajan SG, Hunyara JL, Hamilton NR, Kolodkin AL, Huberman AD. Central nervous system regeneration. Cell 2022; 185:77-94. [PMID: 34995518 PMCID: PMC10896592 DOI: 10.1016/j.cell.2021.10.029] [Citation(s) in RCA: 84] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 02/06/2023]
Abstract
Neurons of the mammalian central nervous system fail to regenerate. Substantial progress has been made toward identifying the cellular and molecular mechanisms that underlie regenerative failure and how altering those pathways can promote cell survival and/or axon regeneration. Here, we summarize those findings while comparing the regenerative process in the central versus the peripheral nervous system. We also highlight studies that advance our understanding of the mechanisms underlying neural degeneration in response to injury, as many of these mechanisms represent primary targets for restoring functional neural circuits.
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Affiliation(s)
| | - John L Hunyara
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Natalie R Hamilton
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Alex L Kolodkin
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Andrew D Huberman
- Department of Neurobiology, Stanford University, Stanford, CA 94305, USA; Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA.
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MicroRNAs 21 and 199a-3p Regulate Axon Growth Potential through Modulation of Pten and mTor mRNAs. eNeuro 2021; 8:ENEURO.0155-21.2021. [PMID: 34326064 PMCID: PMC8362682 DOI: 10.1523/eneuro.0155-21.2021] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 07/11/2021] [Accepted: 07/15/2021] [Indexed: 12/14/2022] Open
Abstract
Increased mTOR activity has been shown to enhance regeneration of injured axons by increasing neuronal protein synthesis, while PTEN signaling can block mTOR activity to attenuate protein synthesis. MicroRNAs (miRs) have been implicated in regulation of PTEN and mTOR expression, and previous work in spinal cord showed an increase in miR-199a-3p after spinal cord injury (SCI) and increase in miR-21 in SCI animals that had undergone exercise. Pten mRNA is a target for miR-21 and miR-199a-3p is predicted to target mTor mRNA. Here, we show that miR-21 and miR-199a-3p are expressed in adult dorsal root ganglion (DRG) neurons, and we used culture preparations to test functions of the rat miRs in adult DRG and embryonic cortical neurons. miR-21 increases and miR-199a-3p decreases in DRG neurons after in vivo axotomy. In both the adult DRG and embryonic cortical neurons, miR-21 promotes and miR-199a-3p attenuates neurite growth. miR-21 directly bound to Pten mRNA and miR-21 overexpression decreased Pten mRNA levels. Conversely, miR-199a-3p directly bound to mTor mRNA and miR-199a-3p overexpression decreased mTor mRNA levels. Overexpressing miR-21 increased both overall and intra-axonal protein synthesis in cultured DRGs, while miR-199a-3p overexpression decreased this protein synthesis. The axon growth phenotypes seen with miR-21 and miR-199a-3p overexpression were reversed by co-transfecting PTEN and mTOR cDNA expression constructs with the predicted 3′ untranslated region (UTR) miR target sequences deleted. Taken together, these studies indicate that injury-induced alterations in miR-21 and miR-199a-3p expression can alter axon growth capacity by changing overall and intra-axonal protein synthesis through regulation of the PTEN/mTOR pathway.
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Giraldo E, Nebot VJ, Đorđević S, Requejo-Aguilar R, Alastrue-Agudo A, Zagorodko O, Armiñan A, Martinez-Rojas B, Vicent MJ, Moreno-Manzano V. A rationally designed self-immolative linker enhances the synergism between a polymer-rock inhibitor conjugate and neural progenitor cells in the treatment of spinal cord injury. Biomaterials 2021; 276:121052. [PMID: 34388362 DOI: 10.1016/j.biomaterials.2021.121052] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 07/04/2021] [Accepted: 07/24/2021] [Indexed: 10/24/2022]
Abstract
Rho/ROCK signaling induced after spinal cord injury (SCI) contributes to secondary damage by promoting apoptosis, inflammation, and axon growth inhibition. The specific Rho-kinase inhibitor fasudil can contribute to functional regeneration after SCI, although inherent low stability has hampered its use. To improve the therapeutic potential of fasudil, we now describe a family of rationally-designed bioresponsive polymer-fasudil conjugates based on an understanding of the conditions after SCI, such as low pH, enhanced expression of specific proteases, and a reductive environment. Fasudil conjugated to poly-l-glutamate via a self-immolative redox-sensitive linker (PGA-SS-F) displays optimal release kinetics and, consequently, treatment with PGA-SS-F significantly induces neurite elongation and axon growth in dorsal root ganglia explants, spinal cord organotypic cultures, and neural precursor cells (NPCs). The intrathecal administration of PGA-SS-F after SCI in a rat model prevents early apoptosis and induces the expression of axonal growth- and neuroplasticity-associated markers to a higher extent than the free form of fasudil. Moreover, a combination treatment comprising the acute transplantation of NPCs pre-treated with PGA-SS-F leads to enhanced cell engraftment and reduced cyst formation after SCI. In chronic SCI, combinatory treatment increases the preservation of neuronal fibers. Overall, this synergistic combinatorial strategy may represent a potentially efficient clinical approach to SCI treatment.
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Affiliation(s)
- E Giraldo
- Neuronal and Tissue Regeneration Lab. Prince Felipe Research Institute, Valencia, Spain; Department of Biotechnology. Universitat Politècnica de València, Valencia, Spain
| | - V J Nebot
- Polymer Therapeutics Lab. Prince Felipe Research Institute, Valencia, Spain; PTS S.L., Valencia, Spain
| | - S Đorđević
- Polymer Therapeutics Lab. Prince Felipe Research Institute, Valencia, Spain
| | - R Requejo-Aguilar
- Neuronal and Tissue Regeneration Lab. Prince Felipe Research Institute, Valencia, Spain; Dept. Biochemistry and Molecular Biology, University of Cordoba, Cordoba, Spain. Maimonides Biomedical Research Institute of Córdoba (IMIBIC), Cordoba, Spain
| | - A Alastrue-Agudo
- Neuronal and Tissue Regeneration Lab. Prince Felipe Research Institute, Valencia, Spain
| | - O Zagorodko
- Polymer Therapeutics Lab. Prince Felipe Research Institute, Valencia, Spain
| | - A Armiñan
- Polymer Therapeutics Lab. Prince Felipe Research Institute, Valencia, Spain
| | - B Martinez-Rojas
- Neuronal and Tissue Regeneration Lab. Prince Felipe Research Institute, Valencia, Spain
| | - M J Vicent
- Polymer Therapeutics Lab. Prince Felipe Research Institute, Valencia, Spain.
| | - V Moreno-Manzano
- Neuronal and Tissue Regeneration Lab. Prince Felipe Research Institute, Valencia, Spain.
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Inhibiting PDE7A Enhances the Protective Effects of Neural Stem Cells on Neurodegeneration and Memory Deficits in Sevoflurane-Exposed Mice. eNeuro 2021; 8:ENEURO.0071-21.2021. [PMID: 34135002 PMCID: PMC8266220 DOI: 10.1523/eneuro.0071-21.2021] [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: 02/19/2021] [Revised: 05/21/2021] [Accepted: 05/25/2021] [Indexed: 12/03/2022] Open
Abstract
Sevoflurane is widely used in general anesthesia, especially for children. However, prolonged exposure to sevoflurane is reported to be associated with adverse effects on the development of brain in infant monkey. Neural stem cells (NSCs), with potent proliferation, differentiation, and renewing ability, provide an encouraging tool for basic research and clinical therapies for neurodegenerative diseases. We aim to explore the functional effects of injecting NSCs with phosphodiesterase 7A (PDE7A) knock-down in infant mice exposed to sevoflurane. The effects of PDE7A in NSCs proliferation and differentiation were determined by cell counting kit-8 (CCK-8) assay and differentiation-related gene expression assay, respectively. The effects of NSCs with modified PDE7A on mice’s long-term memory and learning ability were assessed by behavioral assays. Our data demonstrated that depleting PDE7A promoted, whereas forcing PDE7A suppressed the activation of cAMP/cAMP-response element binding protein (CREB) signaling as well as cell proliferation and neuronal differentiation of NSCs. Inhibition of PDE7A in NSCs exhibited profound improved effects on long-term memory and learning ability of mice exposed to sevoflurane. Our results for the first time show that knock-down of PDE7A improves the neurogenesis of NSCs in vitro and in vivo, and is beneficial for alleviating sevoflurane-induced brain damage in infant mice.
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Application of electrical stimulation for peripheral nerve regeneration: Stimulation parameters and future horizons. INTERDISCIPLINARY NEUROSURGERY 2021. [DOI: 10.1016/j.inat.2021.101117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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BRCA1-BARD1 Regulates Axon Regeneration in Concert with the Gqα-DAG Signaling Network. J Neurosci 2021; 41:2842-2853. [PMID: 33593852 PMCID: PMC8018897 DOI: 10.1523/jneurosci.1806-20.2021] [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: 07/13/2020] [Revised: 01/20/2021] [Accepted: 02/05/2021] [Indexed: 12/27/2022] Open
Abstract
The breast cancer susceptibility protein BRCA1 and its partner BRCA1-associated RING domain protein 1 (BARD1) form an E3-ubiquitin (Ub) ligase complex that acts as a tumor suppressor in mitotic cells. However, the roles of BRCA1–BARD1 in postmitotic cells, such as neurons, remain poorly defined. Here, we report that BRC-1 and BRD-1, the Caenorhabditis elegans orthologs of BRCA1 and BARD1, are required for adult-specific axon regeneration, which is positively regulated by the EGL-30 Gqα–diacylglycerol (DAG) signaling pathway. This pathway is downregulated by DAG kinase (DGK), which converts DAG to phosphatidic acid (PA). We demonstrate that inactivation of DGK-3 suppresses the brc-1 brd-1 defect in axon regeneration, suggesting that BRC-1–BRD-1 inhibits DGK-3 function. Indeed, we show that BRC-1–BRD-1 poly-ubiquitylates DGK-3 in a manner dependent on its E3 ligase activity, causing DGK-3 degradation. Furthermore, we find that axon injury causes the translocation of BRC-1 from the nucleus to the cytoplasm, where DGK-3 is localized. These results suggest that the BRC-1–BRD-1 complex regulates axon regeneration in concert with the Gqα–DAG signaling network. Thus, this study describes a new role for breast cancer proteins in fully differentiated neurons and the molecular mechanism underlying the regulation of axon regeneration in response to nerve injury. SIGNIFICANCE STATEMENT BRCA1–BRCA1-associated RING domain protein 1 (BARD1) is an E3-ubiquitin (Ub) ligase complex acting as a tumor suppressor in mitotic cells. The roles of BRCA1–BARD1 in postmitotic cells, such as neurons, remain poorly defined. We show here that Caenorhabditis elegans BRC-1/BRCA1 and BRD-1/BARD1 are required for adult-specific axon regeneration, a process that requires high diacylglycerol (DAG) levels in injured neurons. The DAG kinase (DGK)-3 inhibits axon regeneration by reducing DAG levels. We find that BRC-1–BRD-1 poly-ubiquitylates and degrades DGK-3, thereby keeping DAG levels elevated and promoting axon regeneration. Furthermore, we demonstrate that axon injury causes the translocation of BRC-1 from the nucleus to the cytoplasm, where DGK-3 is localized. Thus, this study describes a new role for BRCA1–BARD1 in fully-differentiated neurons.
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Liu D, Shu M, Liu W, Shen Y, Long G, Zhao Y, Hou X, Xiao Z, Dai J, Li X. Binary scaffold facilitates in situ regeneration of axons and neurons for complete spinal cord injury repair. Biomater Sci 2021; 9:2955-2971. [PMID: 33634811 DOI: 10.1039/d0bm02212h] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The limited regrowth of transected axons and insufficient regeneration of lost neurons in adult mammals collectively hinder complete spinal cord injury (SCI) repair. Hence, designing an ideal bio-scaffold which could coordinate the regeneration of axons and neurons in situ might be able to effectively facilitate the reconstruction of neural circuits and the recovery of nerve function after complete SCI. In this study, a sponge-like collagen scaffold with good drug release characteristics and good nerve cell compatibility was prepared and used as a drug delivery platform. When doubly modified with Taxol liposomes and collagen-binding neurotrophic factor 3, the scaffold dually alleviated myelin-derived inhibition on neurite outgrowth of neurons and neuronal differentiation of neural stem cells in vitro. Meanwhile, the binary-drug modified scaffold was also able to simultaneously promote both axonal and neuronal regeneration when implanted into a complete transected SCI model. Additionally, the regenerated axons and neurons throughout the lesion site formed extensive synaptic connections. Finally, complete SCI rats that received binary scaffold implantation exhibited optimal neuroelectrophysiological recovery and hindlimb locomotor improvement. Taken together, implantation of the binary scaffold can establish neural bridging networks for functional recovery, representing a clinically promising strategy for complete SCI repair.
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Affiliation(s)
- Dingyang Liu
- Department of Neurosurgery, Xiangya Hospital of Central South University, Changsha, 410008, Hunan Province, China.
| | - Muya Shu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Weiyuan Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yeyu Shen
- Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Changsha 410008, Hunan Province, China and Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha 410008, Hunan Province, China
| | - Ge Long
- Department of Anesthesia, the Third Xiangya Hospital of Central South University, Changsha, 410013, China
| | - Yannan Zhao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xianglin Hou
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhifeng Xiao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jianwu Dai
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xing Li
- Department of Neurosurgery, Xiangya Hospital of Central South University, Changsha, 410008, Hunan Province, China. and Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Changsha 410008, Hunan Province, China and Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha 410008, Hunan Province, China
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31
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Li P, Jia Y, Tang W, Cui Q, Liu M, Jiang J. Roles of Non-coding RNAs in Central Nervous System Axon Regeneration. Front Neurosci 2021; 15:630633. [PMID: 33597844 PMCID: PMC7882506 DOI: 10.3389/fnins.2021.630633] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 01/05/2021] [Indexed: 12/11/2022] Open
Abstract
Axons in the central nervous system often fail to regenerate after injury due to the limited intrinsic regeneration ability of the central nervous system (CNS) and complex extracellular inhibitory factors. Therefore, it is of vital importance to have a better understanding of potential methods to promote the regeneration capability of injured nerves. Evidence has shown that non-coding RNAs play an essential role in nerve regeneration, especially long non-coding RNA (lncRNA), microRNA (miRNA), and circular RNA (circRNA). In this review, we profile their separate roles in axon regeneration after CNS injuries, such as spinal cord injury (SCI) and optic nerve injury. In addition, we also reveal the interactive networks among non-coding RNAs.
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Affiliation(s)
| | | | | | | | | | - Jingjing Jiang
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, China
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32
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Smith GM, Liu Y. Quantitative Assessment of Neurite Outgrowth Over Growth Promoting or Inhibitory Substrates. Methods Mol Biol 2021; 2311:167-175. [PMID: 34033085 DOI: 10.1007/978-1-0716-1437-2_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
The use of sensory neurons and assessment of neurite outgrowth in vitro is an important part of understanding neuronal development and plasticity. Cultures of rat dorsal root ganglion (DRG) neurons provide quantitative results very quickly and, when grown on growth promoting or inhibitory substrates, can be utilized to study axonal growth, neurotrophic dependence, and structure and function of growth cones. Since we are interested in axon regeneration and targeting, we have sought to promote neurite outgrowth by refining the techniques of growing DRG neurons in culture. This chapter describes detailed methods for the dissection and purification of DRG neurons and quantitative assessment of neurite on promoting or inhibitory substrates.
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Affiliation(s)
- George M Smith
- Shriners Hospital Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA.
| | - Yingpeng Liu
- Shriners Hospital Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
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33
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Guijarro-Belmar A, Domanski DM, Bo X, Shewan D, Huang W. The therapeutic potential of targeting exchange protein directly activated by cyclic adenosine 3',5'-monophosphate (Epac) for central nervous system trauma. Neural Regen Res 2021; 16:460-469. [PMID: 32985466 PMCID: PMC7996029 DOI: 10.4103/1673-5374.293256] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Millions of people worldwide are affected by traumatic spinal cord injury, which usually results in permanent sensorimotor disability. Damage to the spinal cord leads to a series of detrimental events including ischaemia, haemorrhage and neuroinflammation, which over time result in further neural tissue loss. Eventually, at chronic stages of traumatic spinal cord injury, the formation of a glial scar, cystic cavitation and the presence of numerous inhibitory molecules act as physical and chemical barriers to axonal regrowth. This is further hindered by a lack of intrinsic regrowth ability of adult neurons in the central nervous system. The intracellular signalling molecule, cyclic adenosine 3′,5′-monophosphate (cAMP), is known to play many important roles in the central nervous system, and elevating its levels as shown to improve axonal regeneration outcomes following traumatic spinal cord injury in animal models. However, therapies directly targeting cAMP have not found their way into the clinic, as cAMP is ubiquitously present in all cell types and its manipulation may have additional deleterious effects. A downstream effector of cAMP, exchange protein directly activated by cAMP 2 (Epac2), is mainly expressed in the adult central nervous system, and its activation has been shown to mediate the positive effects of cAMP on axonal guidance and regeneration. Recently, using ex vivo modelling of traumatic spinal cord injury, Epac2 activation was found to profoundly modulate the post-lesion environment, such as decreasing the activation of astrocytes and microglia. Pilot data with Epac2 activation also suggested functional improvement assessed by in vivo models of traumatic spinal cord injury. Therefore, targeting Epac2 in traumatic spinal cord injury could represent a novel strategy in traumatic spinal cord injury repair, and future work is needed to fully establish its therapeutic potential.
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Affiliation(s)
- Alba Guijarro-Belmar
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen; Sainsbury Wellcome Centre, University College London, London, UK
| | - Dominik Mateusz Domanski
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, UK
| | - Xuenong Bo
- Center for Neuroscience, Surgery and Trauma, Queen Mary University of London, London, UK
| | - Derryck Shewan
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, UK
| | - Wenlong Huang
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, UK
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34
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Tsujioka H, Yamashita T. Neural circuit repair after central nervous system injury. Int Immunol 2020; 33:301-309. [PMID: 33270108 DOI: 10.1093/intimm/dxaa077] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/01/2020] [Indexed: 12/24/2022] Open
Abstract
Central nervous system injury often causes lifelong impairment of neural function, because the regenerative ability of axons is limited, making a sharp contrast to the successful regeneration that is seen in the peripheral nervous system. Nevertheless, partial functional recovery is observed, because axonal branches of damaged or undamaged neurons sprout and form novel relaying circuits. Using a lot of animal models such as the spinal cord injury model or the optic nerve injury model, previous studies have identified many factors that promote or inhibit axonal regeneration or sprouting. Molecules in the myelin such as myelin-associated glycoprotein, Nogo-A or oligodendrocyte-myelin glycoprotein, or molecules found in the glial scar such as chondroitin sulfate proteoglycans, activate Ras homolog A (RhoA) signaling, which leads to the collapse of the growth cone and inhibit axonal regeneration. By contrast, axonal regeneration programs can be activated by many molecules such as regeneration-associated transcription factors, cyclic AMP, neurotrophic factors, growth factors, mechanistic target of rapamycin or immune-related molecules. Axonal sprouting and axonal regeneration largely share these mechanisms. For functional recovery, appropriate pruning or suppressing of aberrant sprouting are also important. In contrast to adults, neonates show much higher sprouting ability. Specific cell types, various mouse strains and different species show higher regenerative ability. Studies focusing on these models also identified a lot of molecules that affect the regenerative ability. A deeper understanding of the mechanisms of neural circuit repair will lead to the development of better therapeutic approaches for central nervous system injury.
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Affiliation(s)
- Hiroshi Tsujioka
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.,WPI Immunology Frontier Research Center, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Toshihide Yamashita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.,WPI Immunology Frontier Research Center, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.,Graduate School of Frontier Bioscience, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.,Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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35
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Glial Metabolic Rewiring Promotes Axon Regeneration and Functional Recovery in the Central Nervous System. Cell Metab 2020; 32:767-785.e7. [PMID: 32941799 PMCID: PMC7642184 DOI: 10.1016/j.cmet.2020.08.015] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 07/07/2020] [Accepted: 08/26/2020] [Indexed: 12/25/2022]
Abstract
Axons in the mature central nervous system (CNS) fail to regenerate after axotomy, partly due to the inhibitory environment constituted by reactive glial cells producing astrocytic scars, chondroitin sulfate proteoglycans, and myelin debris. We investigated this inhibitory milieu, showing that it is reversible and depends on glial metabolic status. We show that glia can be reprogrammed to promote morphological and functional regeneration after CNS injury in Drosophila via increased glycolysis. This enhancement is mediated by the glia derived metabolites: L-lactate and L-2-hydroxyglutarate (L-2HG). Genetically/pharmacologically increasing or reducing their bioactivity promoted or impeded CNS axon regeneration. L-lactate and L-2HG from glia acted on neuronal metabotropic GABAB receptors to boost cAMP signaling. Local application of L-lactate to injured spinal cord promoted corticospinal tract axon regeneration, leading to behavioral recovery in adult mice. Our findings revealed a metabolic switch to circumvent the inhibition of glia while amplifying their beneficial effects for treating CNS injuries.
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Kong G, Zhou L, Serger E, Palmisano I, De Virgiliis F, Hutson TH, Mclachlan E, Freiwald A, La Montanara P, Shkura K, Puttagunta R, Di Giovanni S. AMPK controls the axonal regenerative ability of dorsal root ganglia sensory neurons after spinal cord injury. Nat Metab 2020; 2:918-933. [PMID: 32778834 DOI: 10.1038/s42255-020-0252-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 06/26/2020] [Indexed: 12/25/2022]
Abstract
Regeneration after injury occurs in axons that lie in the peripheral nervous system but fails in the central nervous system, thereby limiting functional recovery. Differences in axonal signalling in response to injury that might underpin this differential regenerative ability are poorly characterized. Combining axoplasmic proteomics from peripheral sciatic or central projecting dorsal root ganglion (DRG) axons with cell body RNA-seq, we uncover injury-dependent signalling pathways that are uniquely represented in peripheral versus central projecting sciatic DRG axons. We identify AMPK as a crucial regulator of axonal regenerative signalling that is specifically downregulated in injured peripheral, but not central, axons. We find that AMPK in DRG interacts with the 26S proteasome and its CaMKIIα-dependent regulatory subunit PSMC5 to promote AMPKα proteasomal degradation following sciatic axotomy. Conditional deletion of AMPKα1 promotes multiple regenerative signalling pathways after central axonal injury and stimulates robust axonal growth across the spinal cord injury site, suggesting inhibition of AMPK as a therapeutic strategy to enhance regeneration following spinal cord injury.
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Affiliation(s)
- Guiping Kong
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Graduate School for Cellular and Molecular Neuroscience, University of Tübingen, Tübingen, Germany
| | - Luming Zhou
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Graduate School for Cellular and Molecular Neuroscience, University of Tübingen, Tübingen, Germany
| | - Elisabeth Serger
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Ilaria Palmisano
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Francesco De Virgiliis
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Thomas H Hutson
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Eilidh Mclachlan
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Anja Freiwald
- Proteomics Core Facility, Institute of Molecular Biology, Mainz, Germany
| | - Paolo La Montanara
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Kirill Shkura
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Radhika Puttagunta
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- University of Heidelberg, Heidelberg, Germany
| | - Simone Di Giovanni
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK.
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.
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37
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Jack AS, Hurd C, Martin J, Fouad K. Electrical Stimulation as a Tool to Promote Plasticity of the Injured Spinal Cord. J Neurotrauma 2020; 37:1933-1953. [PMID: 32438858 DOI: 10.1089/neu.2020.7033] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Unlike their peripheral nervous system counterparts, the capacity of central nervous system neurons and axons for regeneration after injury is minimal. Although a myriad of therapies (and different combinations thereof) to help promote repair and recovery after spinal cord injury (SCI) have been trialed, few have progressed from bench-top to bedside. One of the few such therapies that has been successfully translated from basic science to clinical applications is electrical stimulation (ES). Although the use and study of ES in peripheral nerve growth dates back nearly a century, only recently has it started to be used in a clinical setting. Since those initial experiments and seminal publications, the application of ES to restore function and promote healing have greatly expanded. In this review, we discuss the progression and use of ES over time as it pertains to promoting axonal outgrowth and functional recovery post-SCI. In doing so, we consider four major uses for the study of ES based on the proposed or documented underlying mechanism: (1) using ES to introduce an electric field at the site of injury to promote axonal outgrowth and plasticity; (2) using spinal cord ES to activate or to increase the excitability of neuronal networks below the injury; (3) using motor cortex ES to promote corticospinal tract axonal outgrowth and plasticity; and (4) leveraging the timing of paired stimuli to produce plasticity. Finally, the use of ES in its current state in the context of human SCI studies is discussed, in addition to ongoing research and current knowledge gaps, to highlight the direction of future studies for this therapeutic modality.
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Affiliation(s)
- Andrew S Jack
- Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, California, USA
| | - Caitlin Hurd
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - John Martin
- Department of Molecular, Cellular, and Biomedical Sciences, City University of New York School of Medicine, and City University of New York Graduate Center, New York, New York, USA
| | - Karim Fouad
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada.,Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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Moradi K, Golbakhsh M, Haghighi F, Afshari K, Nikbakhsh R, Khavandi MM, Faghani S, Badripour A, Etemadi A, Ashraf-Ganjouei A, Bagheri S, Dehpour AR. Inhibition of phosphodiesterase IV enzyme improves locomotor and sensory complications of spinal cord injury via altering microglial activity: Introduction of Roflumilast as an alternative therapy. Int Immunopharmacol 2020; 86:106743. [PMID: 32619958 DOI: 10.1016/j.intimp.2020.106743] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/06/2020] [Accepted: 06/23/2020] [Indexed: 02/02/2023]
Abstract
Despite the great search for an effective approach to minimize secondary injury in spinal cord injury (SCI) setting, there have been limited advances. Roflumilast is a selective inhibitor of phosphodiesterase 4 with potent anti-inflammatory properties. Here, we sought to explore Roflumilast efficacy in the improvement of locomotor and sensory deficits of SCI. In an animal setting, 50 male rats were randomly assigned to five groups: an SCI group receiving Placebo, three SCI groups receiving Roflumilast at the doses of 0.25, 0.5, and 1 mg/kg prior to T9 vertebra laminectomy, and a sham-operated group. Locomotor, mechanical, and thermal activities were evaluated for 28 days. At the end of the study, spinal cord samples were taken to assess the relative ratio of microglial subtypes, including M1 and M2, histopathological changes, levels of pro-inflammatory (TNF-α and IL-1β) and anti-inflammatory (IL-10) biomarkers, and cAMP level. Repeated measure analysis revealed significant effect for time-treatment interaction on locomotion [F (24, 270) = 280.7, p < 0.001], thermal sensitivity [F (16, 180) = 4.35, p < 0.001], and mechanical sensitivity [F (16, 180) = 7.96, p < 0.001]. As expected, Roflumilast significantly increased the expression of spinal cAMP. H&E staining exhibited lesser histopathological disruptions in Roflumilast-treated rodents. We also observed a significant reduction in the M1/M2 ratio (p values < 0.001) as well as in pro-inflammatory biomarkers following the administration of Roflumilast to the injured rats. Furthermore, IL-10 level was increased in rodents receiving 1 mg/kg of the reagent. In conclusion, the increased spinal cAMP following Roflumilast therapy might attenuate neuroinflammation via altering microglial activity; therefore, it could be considered as an alternative therapeutic agent for SCI complications.
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Affiliation(s)
- Kamyar Moradi
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammadreza Golbakhsh
- Department of Orthopedic Surgery, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Farinaz Haghighi
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Khashayar Afshari
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Rajan Nikbakhsh
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Mahdi Khavandi
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Shahriar Faghani
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Abolfazl Badripour
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Etemadi
- Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Ashraf-Ganjouei
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Sayna Bagheri
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmad Reza Dehpour
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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Smith TP, Sahoo PK, Kar AN, Twiss JL. Intra-axonal mechanisms driving axon regeneration. Brain Res 2020; 1740:146864. [PMID: 32360100 DOI: 10.1016/j.brainres.2020.146864] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 04/24/2020] [Accepted: 04/27/2020] [Indexed: 12/27/2022]
Abstract
Traumatic injury to the peripheral and central nervous systems very often causes axotomy, where an axon loses connections with its target resulting in loss of function. The axon segments distal to the injury site lose connection with the cell body and degenerate. Axotomized neurons in the periphery can spontaneously mount a regenerative response and reconnect to their denervated target tissues, though this is rarely complete in humans. In contrast, spontaneous regeneration rarely occurs after axotomy in the spinal cord and brain. Here, we concentrate on the mechanisms underlying this spontaneous regeneration in the peripheral nervous system, focusing on events initiated from the axon that support regenerative growth. We contrast this with what is known for axonal injury responses in the central nervous system. Considering the neuropathy focus of this special issue, we further draw parallels and distinctions between the injury-response mechanisms that initiate regenerative gene expression programs and those that are known to trigger axon degeneration.
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Affiliation(s)
- Terika P Smith
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Pabitra K Sahoo
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Amar N Kar
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA.
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Patel NJ, Hogan KJ, Rizk E, Stewart K, Madrid A, Vadakkadath Meethal S, Alisch R, Borth L, Papale LA, Ondoma S, Gorges LR, Weber K, Lake W, Bauer A, Hariharan N, Kuehn T, Cook T, Keles S, Newton MA, Iskandar BJ. Ancestral Folate Promotes Neuronal Regeneration in Serial Generations of Progeny. Mol Neurobiol 2020; 57:2048-2071. [PMID: 31919777 PMCID: PMC7125003 DOI: 10.1007/s12035-019-01812-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 10/07/2019] [Indexed: 12/17/2022]
Abstract
Folate supplementation in F0 mating rodents increases regeneration of injured spinal axons in vivo in 4 or more generations of progeny (F1-F4) in the absence of interval folate administration to the progeny. Transmission of the enhanced regeneration phenotype to untreated progeny parallels axonal growth in neuron culture after in vivo folate administration to the F0 ancestors alone, in correlation with differential patterns of genomic DNA methylation and RNA transcription in treated lineages. Enhanced axonal regeneration phenotypes are observed with diverse folate preparations and routes of administration, in outbred and inbred rodent strains, and in two rodent genera comprising rats and mice, and are reversed in F4-F5 progeny by pretreatment with DNA demethylating agents prior to phenotyping. Uniform transmission of the enhanced regeneration phenotype to progeny together with differential patterns of DNA methylation and RNA expression is consistent with a non-Mendelian mechanism. The capacity of an essential nutritional co-factor to induce a beneficial transgenerational phenotype in untreated offspring carries broad implications for the diagnosis, prevention, and treatment of inborn and acquired disorders.
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Affiliation(s)
- Nirav J Patel
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA
| | - Kirk J Hogan
- Department of Anesthesiology, University of Wisconsin, Madison, WI, USA
| | - Elias Rizk
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA
| | - Krista Stewart
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA
| | - Andy Madrid
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA
| | - Sivan Vadakkadath Meethal
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA
| | - Reid Alisch
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA
| | - Laura Borth
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA
| | - Ligia A Papale
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA
| | - Solomon Ondoma
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA
| | - Logan R Gorges
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA
| | - Kara Weber
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA
| | - Wendell Lake
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA
| | - Andrew Bauer
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA
| | - Nithya Hariharan
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA
| | - Thomas Kuehn
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA
| | - Thomas Cook
- Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison, WI, USA
| | - Sunduz Keles
- Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison, WI, USA
- Department of Statistics, University of Wisconsin, Madison, WI, USA
| | - Michael A Newton
- Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison, WI, USA
- Department of Statistics, University of Wisconsin, Madison, WI, USA
| | - Bermans J Iskandar
- Department of Neurological Surgery, University of Wisconsin, 600 Highland Avenue, K4/832, Madison, WI, 53792, USA.
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41
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Epac2 Promotes Axonal Outgrowth and Attenuates the Glial Reaction in an Ex Vivo Model of Spinal Cord Injury. J Neurosci 2020; 40:2184-2185. [PMID: 32161180 DOI: 10.1523/jneurosci.2450-19.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/17/2020] [Accepted: 01/21/2020] [Indexed: 01/25/2023] Open
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Griffin JM, Bradke F. Therapeutic repair for spinal cord injury: combinatory approaches to address a multifaceted problem. EMBO Mol Med 2020; 12:e11505. [PMID: 32090481 PMCID: PMC7059014 DOI: 10.15252/emmm.201911505] [Citation(s) in RCA: 110] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 01/07/2020] [Accepted: 01/31/2020] [Indexed: 12/21/2022] Open
Abstract
The recent years saw the advent of promising preclinical strategies that combat the devastating effects of a spinal cord injury (SCI) that are progressing towards clinical trials. However, individually, these treatments produce only modest levels of recovery in animal models of SCI that could hamper their implementation into therapeutic strategies in spinal cord injured humans. Combinational strategies have demonstrated greater beneficial outcomes than their individual components alone by addressing multiple aspects of SCI pathology. Clinical trial designs in the future will eventually also need to align with this notion. The scenario will become increasingly complex as this happens and conversations between basic researchers and clinicians are required to ensure accurate study designs and functional readouts.
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Affiliation(s)
- Jarred M Griffin
- Laboratory for Axonal Growth and Regeneration, German Centre for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Frank Bradke
- Laboratory for Axonal Growth and Regeneration, German Centre for Neurodegenerative Diseases (DZNE), Bonn, Germany
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43
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Nikulina E, Gkioka V, Siddiq MM, Mellado W, Hilaire M, Cain CR, Hannila SS, Filbin MT. Myelin-associated glycoprotein inhibits neurite outgrowth through inactivation of the small GTPase Rap1. FEBS Lett 2020; 594:1389-1402. [PMID: 31985825 DOI: 10.1002/1873-3468.13740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 11/05/2022]
Abstract
Rap1 is a small GTPase that has been implicated in dendritic development and plasticity. In this study, we investigated the role of Rap1 in axonal growth and its activation in response to neurotrophins and myelin-associated inhibitors. We report that Rap1 is activated by brain-derived neurotrophic factor and that this activation can be blocked by myelin-associated glycoprotein (MAG) or central nervous system myelin, which also induced increases in Rap1GAP1 levels. In addition, we demonstrate that adenoviral overexpression of Rap1 enhances neurite outgrowth in the presence of MAG and myelin, while inhibition of Rap1 activity through overexpression of Rap1GAP1 blocks neurite outgrowth. These findings suggest that Rap1GAP1 negatively regulates neurite outgrowth, making it a potential therapeutic target to promote axonal regeneration.
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Affiliation(s)
- Elena Nikulina
- Department of Biological Sciences, Hunter College, City University of New York, NY, USA
| | - Vasiliki Gkioka
- Department of Biological Sciences, Hunter College, City University of New York, NY, USA
| | - Mustafa M Siddiq
- Icahn Medical Institute 12-52, Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, NY, USA
| | | | - Melissa Hilaire
- Department of Biological Sciences, Hunter College, City University of New York, NY, USA
| | - Christine R Cain
- Department of Biological Sciences, Hunter College, City University of New York, NY, USA
| | - Sari S Hannila
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Marie T Filbin
- Department of Biological Sciences, Hunter College, City University of New York, NY, USA
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44
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The Cellular and Molecular Patterns Involved in the Neural Differentiation of Adipose-Derived Stem Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1298:23-41. [PMID: 32514816 DOI: 10.1007/5584_2020_547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Injuries to the nervous system cause serious problems among affected patients by preventing them from the possibility of living a normal life. As this tissue possesses a reduced capacity of self-regeneration currently, lots of different strategies are being developed in order to make the regeneration in the nervous system possible. Among them, tissue engineering and stem cell-based therapies are to date very exploded fields and tremendous progress has been made in this direction. As the two main components of the nervous system, react differently to injuries and behave different during disease, it is clear that two separate regeneration approaches have been taken into consideration during development of treatment. Special attention is constantly given to the potential of adipose-derived stem cells for this kind of application. Due to the fact that they present remarkable properties, they can easily be obtained and have demonstrated that are capable of engaging in neural and glial lineages, adipose-derived stem cells are promising tools for the field of nervous system regeneration. Moreover, new insights into epigenetic control and modifications during the differentiation of adipose-derived stem cells towards the neural liege could provide new methods to maximize the regeneration process. In this review, we summarize the current applications of adipose-derived stem cells for neural regeneration and discuss in-depth molecular patterns involved in the differentiation of adipose-derived stem cells in neuron-like cells and Schwann-like cells.
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45
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Liu Y, Wang H. Peripheral nerve injury induced changes in the spinal cord and strategies to counteract/enhance the changes to promote nerve regeneration. Neural Regen Res 2020; 15:189-198. [PMID: 31552884 PMCID: PMC6905333 DOI: 10.4103/1673-5374.265540] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Peripheral nerve injury leads to morphological, molecular and gene expression changes in the spinal cord and dorsal root ganglia, some of which have positive impact on the survival of neurons and nerve regeneration, while the effect of others is the opposite. It is crucial to take prompt measures to capitalize on the positive effects of these reactions and counteract the negative impact after peripheral nerve injury at the level of spinal cord, especially for peripheral nerve injuries that are severe, located close to the cell body, involve long distance for axons to regrow and happen in immature individuals. Early nerve repair, exogenous supply of neurotrophic factors and Schwann cells can sustain the regeneration inductive environment and enhance the positive changes in neurons. Administration of neurotrophic factors, acetyl-L-carnitine, N-acetyl-cysteine, and N-methyl-D-aspartate receptor antagonist MK-801 can help counteract axotomy-induced neuronal loss and promote regeneration, which are all time-dependent. Sustaining and reactivation of Schwann cells after denervation provides another effective strategy. FK506 can be used to accelerate axonal regeneration of neurons, especially after chronic axotomy. Exploring the axotomy-induced changes after peripheral nerve injury and applying protective and promotional measures in the spinal cord which help to retain a positive functional status for neuron cell bodies will inevitably benefit regeneration of the peripheral nerve and improve functional outcomes.
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Affiliation(s)
- Yan Liu
- Department of Hand Surgery, China-Japan Union Hospital of Jilin University, Changchun, Jilin Province, China; Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Huan Wang
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA
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46
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Gao X, Zhang X, Cui L, Chen R, Zhang C, Xue J, Zhang L, He W, Li J, Wei S, Wei M, Cui H. Ginsenoside Rb1 Promotes Motor Functional Recovery and Axonal Regeneration in Post-stroke Mice through cAMP/PKA/CREB Signaling Pathway. Brain Res Bull 2019; 154:51-60. [PMID: 31715311 DOI: 10.1016/j.brainresbull.2019.10.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 09/29/2019] [Accepted: 10/19/2019] [Indexed: 11/29/2022]
Abstract
The central nervous system (CNS) has a poor self-repairing capability after injury because of the inhibition of axonal regeneration by many myelin-associated inhibitory factors. Therefore, ischemic stroke usually leads to disability. Previous studies reported that Ginsenoside Rb1 (GRb1) plays a role in neuronal protection in acute phase after ischemic stroke, but its efficacy in post-stroke and the underlying mechanism are not clear. Recent evidences demonstrated GRb1 promotes neurotransmitter release through the cAMP-depend protein kinase A (PKA) pathway, which is related to axonal regeneration. The present study aimed to determine whether GRb1 improves long-term motor functional recovery and promotes cortical axon regeneration in post-stroke. Adult male C57BL/6 mice were subjected to distal middle cerebral artery occlusion (dMCAO). GRb1 solution (5 mg/ml) or equal volume of normal saline was injected intraperitoneally for the first time at 24 h after surgery, and then daily injected until day 14. Day 3, 7, 14 and 28 after dMCAO were used as observation time points. Motor functional recovery was assessed with Rota-rod test and grid walking task. The expression of growth-associated protein 43 (GAP43) and biotinylated dextran amine (BDA) was measured to evaluate axonal regeneration. The levels of cyclic AMP (cAMP) and PKA were measured by Elisa, PKAc and phosphorylated cAMP response element protein (pCREB) were determined by western blot. Our results shown that GRb1 treatment improved motor function and increased the expression of GAP43 and BDA in ipsilesional and contralateral cortex. GRb1 significantly elevated cAMP and PKA, increased the protein expression of PKAc and pCREB. However, the effects of GRb1 were eliminated by H89 intervention (a PKA inhibitor). These results suggested that GRb1 improved functional recovery in post-stroke by stimulating axonal regeneration and brain repair. The underlying mechanism might be up-regulating the expression of cAMP/PKA/CREB pathway.
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Affiliation(s)
- Xuan Gao
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Xiangjian Zhang
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China; Hebei Key Laboratory of Vascular Homeostasis and Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China.
| | - Lili Cui
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China; Hebei Key Laboratory of Vascular Homeostasis and Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Rong Chen
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China; Hebei Key Laboratory of Vascular Homeostasis and Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Cong Zhang
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Jing Xue
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Lan Zhang
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Weiliang He
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Jiamin Li
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Shanshan Wei
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Mengmeng Wei
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
| | - Hemei Cui
- Department of Neurology, Second Hospital of Hebei Medical University, 215 Hepingxi Road, Shijiazhuang, Hebei, 050000, PR China
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Barros Ribeiro da Silva V, Porcionatto M, Toledo Ribas V. The Rise of Molecules Able To Regenerate the Central Nervous System. J Med Chem 2019; 63:490-511. [PMID: 31518122 DOI: 10.1021/acs.jmedchem.9b00863] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Injury to the adult central nervous system (CNS) usually leads to permanent deficits of cognitive, sensory, and/or motor functions. The failure of axonal regeneration in the damaged CNS limits functional recovery. The lack of information concerning the biological mechanism of axonal regeneration and its complexity has delayed the process of drug discovery for many years compared to other drug classes. Starting in the early 2000s, the ability of many molecules to stimulate axonal regrowth was evaluated through automated screening techniques; many hits and some new mechanisms involved in axonal regeneration were identified. In this Perspective, we discuss the rise of the CNS regenerative drugs, the main biological techniques used to test these drug candidates, some of the most important screens performed so far, and the main challenges following the identification of a drug that is able to induce axonal regeneration in vivo.
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Affiliation(s)
| | - Marimélia Porcionatto
- Universidade Federal de São Paulo , Escola Paulista de Medicina, Laboratório de Neurobiologia Molecular, Departmento de Bioquímica , Rua Pedro de Toledo, 669 - third floor, 04039-032 São Paulo , São Paolo , Brazil
| | - Vinicius Toledo Ribas
- Universidade Federal de Minas Gerais , Instituto de Ciências Biológicas, Departamento de Morfologia, Laboratório de Neurobiologia Av. Antônio Carlos, 6627, room O3-245 , - Campus Pampulha, 31270-901 , Belo Horizonte , Minas Gerais , Brazil
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48
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Epac2 Elevation Reverses Inhibition by Chondroitin Sulfate Proteoglycans In Vitro and Transforms Postlesion Inhibitory Environment to Promote Axonal Outgrowth in an Ex Vivo Model of Spinal Cord Injury. J Neurosci 2019; 39:8330-8346. [PMID: 31409666 DOI: 10.1523/jneurosci.0374-19.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 08/05/2019] [Accepted: 08/08/2019] [Indexed: 02/07/2023] Open
Abstract
Millions of patients suffer from debilitating spinal cord injury (SCI) without effective treatments. Elevating cAMP promotes CNS neuron growth in the presence of growth-inhibiting molecules. cAMP's effects on neuron growth are partly mediated by Epac, comprising Epac1 and Epac2; the latter predominantly expresses in postnatal neural tissue. Here, we hypothesized that Epac2 activation would enhance axonal outgrowth after SCI. Using in vitro assays, we demonstrated, for the first time, that Epac2 activation using a specific soluble agonist (S-220) significantly enhanced neurite outgrowth of postnatal rat cortical neurons and markedly overcame the inhibition by chondroitin sulfate proteoglycans and mature astrocytes on neuron growth. We further investigated the novel potential of Epac2 activation in promoting axonal outgrowth by an ex vivo rat model of SCI mimicking post-SCI environment in vivo and by delivering S-220 via a self-assembling Fmoc-based hydrogel that has suitable properties for SCI repair. We demonstrated that S-220 significantly enhanced axonal outgrowth across the lesion gaps in the organotypic spinal cord slices, compared with controls. Furthermore, we elucidated, for the first time, that Epac2 activation profoundly modulated the lesion environment by reducing astrocyte/microglial activation and transforming astrocytes into elongated morphology that guided outgrowing axons. Finally, we showed that S-220, when delivered by the gel at 3 weeks after contusion SCI in male adult rats, resulted in significantly better locomotor performance for up to 4 weeks after treatment. Our data demonstrate a promising therapeutic potential of S-220 in SCI, via beneficial effects on neurons and glia after injury to facilitate axonal outgrowth.SIGNIFICANCE STATEMENT During development, neuronal cAMP levels decrease significantly compared with the embryonic stage when the nervous system is established. This has important consequences following spinal cord injury, as neurons fail to regrow. Elevating cAMP levels encourages injured CNS neurons to sprout and extend neurites. We have demonstrated that activating its downstream effector, Epac2, enhances neurite outgrowth in vitro, even in the presence of an inhibitory environment. Using a novel biomaterial-based drug delivery system in the form of a hydrogel to achieve local delivery of an Epac2 agonist, we further demonstrated that specific activation of Epac2 enhances axonal outgrowth and minimizes glial activation in an ex vivo model of spinal cord injury, suggesting a new strategy for spinal cord repair.
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49
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Tedeschi A, Dupraz S, Curcio M, Laskowski CJ, Schaffran B, Flynn KC, Santos TE, Stern S, Hilton BJ, Larson MJE, Gurniak CB, Witke W, Bradke F. ADF/Cofilin-Mediated Actin Turnover Promotes Axon Regeneration in the Adult CNS. Neuron 2019; 103:1073-1085.e6. [PMID: 31400829 DOI: 10.1016/j.neuron.2019.07.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 06/06/2019] [Accepted: 07/08/2019] [Indexed: 11/27/2022]
Abstract
Injured axons fail to regenerate in the adult CNS, which contrasts with their vigorous growth during embryonic development. We explored the potential of re-initiating axon extension after injury by reactivating the molecular mechanisms that drive morphogenetic transformation of neurons during development. Genetic loss- and gain-of-function experiments followed by time-lapse microscopy, in vivo imaging, and whole-mount analysis show that axon regeneration is fueled by elevated actin turnover. Actin depolymerizing factor (ADF)/cofilin controls actin turnover to sustain axon regeneration after spinal cord injury through its actin-severing activity. This pinpoints ADF/cofilin as a key regulator of axon growth competence, irrespective of developmental stage. These findings reveal the central role of actin dynamics regulation in this process and elucidate a core mechanism underlying axon growth after CNS trauma. Thereby, neurons maintain the capacity to stimulate developmental programs during adult life, expanding their potential for plasticity. Thus, actin turnover is a key process for future regenerative interventions.
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Affiliation(s)
- Andrea Tedeschi
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Sebastian Dupraz
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Michele Curcio
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Claudia J Laskowski
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Barbara Schaffran
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Kevin C Flynn
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Telma E Santos
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Sina Stern
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Brett J Hilton
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Molly J E Larson
- Center for Brain and Spinal Cord Repair, Department of Neuroscience, Wexner Medical Center, The Ohio State University, 460 W. 12th Ave., Columbus, OH 43210, USA
| | - Christine B Gurniak
- Institute of Genetics, University of Bonn, Karlrobert-Kreiten-Str. 13, 53115 Bonn, Germany
| | - Walter Witke
- Institute of Genetics, University of Bonn, Karlrobert-Kreiten-Str. 13, 53115 Bonn, Germany
| | - Frank Bradke
- Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany.
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50
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Hassanpour Golakani M, Mohammad MG, Li H, Gamble J, Breit SN, Ruitenberg MJ, Brown DA. MIC-1/GDF15 Overexpression Is Associated with Increased Functional Recovery in Traumatic Spinal Cord Injury. J Neurotrauma 2019; 36:3410-3421. [PMID: 31232176 DOI: 10.1089/neu.2019.6421] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Spinal cord injury (SCI) has devastating consequences, with limited therapeutic options; therefore, improving its functional outcome is a major goal. The outcome of SCI is contributed to by neuroinflammation, which may be a target for improved recovery and quality of life after injury. Macrophage inhibitory cytokine-1/growth differentiation factor 15 (MIC-1/GDF15) has been identified as a potential novel therapy for central nervous system (CNS) injury because it is an immune regulatory cytokine with neurotrophic properties. Here we used MIC-1/GDF15 knockout (KO) and overexpressing/transgenic (Tg) and wild type (WT) animals to explore its putative therapeutic benefits in a mouse model of contusive SCI. MIC-1/GDF15 Tg mice had superior locomotor recovery and reduced secondary tissue loss at 28 days compared with their KO and WT counterparts. Overexpression of MIC-1/GDF15 coincided with increased expression of monocyte chemoattractant protein-1 (MCP-1)/C-C Motif Chemokine Ligand 2 (CCL2) at the lesion site (28 days post-SCI) and enhanced recruitment of inflammatory cells to the injured spinal cord. This inflammatory cellular infiltrate included an increased frequency of macrophages and dendritic cells (DCs) that mostly preceded recruitment of cluster of differentiation (CD)4+ and CD8+ T cells. Collectively, our findings suggest hat MIC-1/GDF15 is associated with beneficial changes in the clinical course of SCI that are characterized by altered post-injury inflammation and improved functional outcome. Further investigation of MIC-1/GDF15 as a novel therapeutic target for traumatic SCI appears warranted.
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Affiliation(s)
- Masoud Hassanpour Golakani
- St. Vincent's Centre for Applied Medical Research (AMR), St Vincent's Hospital and University of New South Wales (UNSW), Sydney, New South Wales, Australia.,The Neuroinflammation Research Group, Centre for Immunology and Allergy Research, Westmead Institute for Medical Research, University of Sydney, Sydney, New South Wales, Australia
| | - Mohammad G Mohammad
- Department of Medical Laboratory Sciences, College of Health Sciences and Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates. Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
| | - Hui Li
- St. Vincent's Centre for Applied Medical Research (AMR), St Vincent's Hospital and University of New South Wales (UNSW), Sydney, New South Wales, Australia.,The Neuroinflammation Research Group, Centre for Immunology and Allergy Research, Westmead Institute for Medical Research, University of Sydney, Sydney, New South Wales, Australia
| | - Joanne Gamble
- The Neuroinflammation Research Group, Centre for Immunology and Allergy Research, Westmead Institute for Medical Research, University of Sydney, Sydney, New South Wales, Australia
| | - Samuel N Breit
- St. Vincent's Centre for Applied Medical Research (AMR), St Vincent's Hospital and University of New South Wales (UNSW), Sydney, New South Wales, Australia
| | - Marc J Ruitenberg
- School of Biomedical Sciences, Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
| | - David A Brown
- St. Vincent's Centre for Applied Medical Research (AMR), St Vincent's Hospital and University of New South Wales (UNSW), Sydney, New South Wales, Australia.,The Neuroinflammation Research Group, Centre for Immunology and Allergy Research, Westmead Institute for Medical Research, University of Sydney, Sydney, New South Wales, Australia.,Department of Immunopathology, Institute for Clinical Pathology and Medical Research-New South Wales Health Pathology, Westmead Hospital, Sydney, New South Wales, Australia
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