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Park E, Lyon JG, Alvarado-Velez M, Betancur MI, Mokarram N, Shin JH, Bellamkonda RV. Enriching neural stem cell and anti-inflammatory glial phenotypes with electrical stimulation after traumatic brain injury in male rats. J Neurosci Res 2021; 99:1864-1884. [PMID: 33772860 PMCID: PMC8360147 DOI: 10.1002/jnr.24834] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 03/08/2021] [Indexed: 12/26/2022]
Abstract
Traumatic brain injury (TBI) by an external physical impact results in compromised brain function via undesired neuronal death. Following the injury, resident and peripheral immune cells, astrocytes, and neural stem cells (NSCs) cooperatively contribute to the recovery of the neuronal function after TBI. However, excessive pro‐inflammatory responses of immune cells, and the disappearance of endogenous NSCs at the injury site during the acute phase of TBI, can exacerbate TBI progression leading to incomplete healing. Therefore, positive outcomes may depend on early interventions to control the injury‐associated cellular milieu in the early phase of injury. Here, we explore electrical stimulation (ES) of the injury site in a rodent model (male Sprague–Dawley rats) to investigate its overall effect on the constituent brain cell phenotype and composition during the acute phase of TBI. Our data showed that a brief ES for 1 hr on day 2 of TBI promoted anti‐inflammatory phenotypes of microglia as assessed by CD206 expression and increased the population of NSCs and Nestin+ astrocytes at 7 days post‐TBI. Also, ES effectively increased the number of viable neurons when compared to the unstimulated control group. Given the salience of microglia and neural stem cells for healing after TBI, our results strongly support the potential benefit of the therapeutic use of ES during the acute phase of TBI to regulate neuroinflammation and to enhance neuroregeneration.
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Affiliation(s)
- Eunyoung Park
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Johnathan G Lyon
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Melissa Alvarado-Velez
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Martha I Betancur
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Nassir Mokarram
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Jennifer H Shin
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Ravi V Bellamkonda
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
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2
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Purvis EM, O'Donnell JC, Chen HI, Cullen DK. Tissue Engineering and Biomaterial Strategies to Elicit Endogenous Neuronal Replacement in the Brain. Front Neurol 2020; 11:344. [PMID: 32411087 PMCID: PMC7199479 DOI: 10.3389/fneur.2020.00344] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 04/07/2020] [Indexed: 12/19/2022] Open
Abstract
Neurogenesis in the postnatal mammalian brain is known to occur in the dentate gyrus of the hippocampus and the subventricular zone. These neurogenic niches serve as endogenous sources of neural precursor cells that could potentially replace neurons that have been lost or damaged throughout the brain. As an example, manipulation of the subventricular zone to augment neurogenesis has become a popular strategy for attempting to replace neurons that have been lost due to acute brain injury or neurodegenerative disease. In this review article, we describe current experimental strategies to enhance the regenerative potential of endogenous neural precursor cell sources by enhancing cell proliferation in neurogenic regions and/or redirecting migration, including pharmacological, biomaterial, and tissue engineering strategies. In particular, we discuss a novel replacement strategy based on exogenously biofabricated "living scaffolds" that could enhance and redirect endogenous neuroblast migration from the subventricular zone to specified regions throughout the brain. This approach utilizes the first implantable, biomimetic tissue-engineered rostral migratory stream, thereby leveraging the brain's natural mechanism for sustained neuronal replacement by replicating the structure and function of the native rostral migratory stream. Across all these strategies, we discuss several challenges that need to be overcome to successfully harness endogenous neural precursor cells to promote nervous system repair and functional restoration. With further development, the diverse and innovative tissue engineering and biomaterial strategies explored in this review have the potential to facilitate functional neuronal replacement to mitigate neurological and psychiatric symptoms caused by injury, developmental disorders, or neurodegenerative disease.
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Affiliation(s)
- Erin M. Purvis
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - John C. O'Donnell
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - H. Isaac Chen
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - D. Kacy Cullen
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, United States
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3
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Girouard MP, Simas T, Hua L, Morquette B, Khazaei MR, Unsain N, Johnstone AD, Rambaldi I, Sanz RL, Di Raddo ME, Gamage KK, Yong Y, Willis DE, Verge VMK, Barker PA, Deppmann C, Fournier AE. Collapsin Response Mediator Protein 4 (CRMP4) Facilitates Wallerian Degeneration and Axon Regeneration following Sciatic Nerve Injury. eNeuro 2020; 7:ENEURO.0479-19.2020. [PMID: 32001550 PMCID: PMC7053045 DOI: 10.1523/eneuro.0479-19.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 01/14/2020] [Accepted: 01/15/2020] [Indexed: 11/29/2022] Open
Abstract
In contrast to neurons in the CNS, damaged neurons from the peripheral nervous system (PNS) regenerate, but this process can be slow and imperfect. Successful regeneration is orchestrated by cytoskeletal reorganization at the tip of the proximal axon segment and cytoskeletal disassembly of the distal segment. Collapsin response mediator protein 4 (CRMP4) is a cytosolic phospho-protein that regulates the actin and microtubule cytoskeleton. During development, CRMP4 promotes growth cone formation and dendrite development. Paradoxically, in the adult CNS, CRMP4 impedes axon regeneration. Here, we investigated the involvement of CRMP4 in peripheral nerve injury in male and female Crmp4-/- mice following sciatic nerve injury. We find that sensory axon regeneration and Wallerian degeneration are impaired in Crmp4-/- mice following sciatic nerve injury. In vitro analysis of dissociated dorsal root ganglion (DRG) neurons from Crmp4-/- mice revealed that CRMP4 functions in the proximal axon segment to promote the regrowth of severed DRG neurons and in the distal axon segment where it facilitates Wallerian degeneration through calpain-dependent formation of harmful CRMP4 fragments. These findings reveal an interesting dual role for CRMP4 in proximal and distal axon segments of injured sensory neurons that coordinately facilitate PNS axon regeneration.
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Affiliation(s)
- Marie-Pier Girouard
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | - Tristan Simas
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | - Luyang Hua
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | - Barbara Morquette
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | - Mohamad R Khazaei
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | - Nicolas Unsain
- Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 5016 Córdoba, Argentina
| | - Aaron D Johnstone
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | - Isabel Rambaldi
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | - Ricardo L Sanz
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | | | - Kanchana K Gamage
- Department of Biology, University of Virginia, Charlottesville, Virginia 22903
| | - Yu Yong
- Department of Biology, University of Virginia, Charlottesville, Virginia 22903
| | - Dianna E Willis
- Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York 10065
- Burke Institute, Weill Cornell Medicine, White Plains, New York 10605
| | - Valerie M K Verge
- Department of Anatomy, Physiology and Pharmacology, University of Saskatchewan-CMSNRC, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Philip A Barker
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
- Department of Biology, University of British Columbia, Kelowna, British Columbia V1V 1V7, Canada
| | | | - Alyson E Fournier
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
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4
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Abstract
Injuries to the peripheral nervous system are major sources of disability and often result in painful neuropathies or the impairment of muscle movement and/or normal sensations. For gaps smaller than 10 mm in rodents, nearly normal functional recovery can be achieved; for longer gaps, however, there are challenges that have remained insurmountable. The current clinical gold standard used to bridge long, nonhealing nerve gaps, the autologous nerve graft (autograft), has several drawbacks. Despite best efforts, engineering an alternative "nerve bridge" for peripheral nerve repair remains elusive; hence, there is a compelling need to design new approaches that match or exceed the performance of autografts across critically sized nerve gaps. Here an immunomodulatory approach to stimulating nerve repair in a nerve-guidance scaffold was used to explore the regenerative effect of reparative monocyte recruitment. Early modulation of the immune environment at the injury site via fractalkine delivery resulted in a dramatic increase in regeneration as evident from histological and electrophysiological analyses. This study suggests that biasing the infiltrating inflammatory/immune cellular milieu after injury toward a proregenerative population creates a permissive environment for repair. This approach is a shift from the current modes of clinical and laboratory methods for nerve repair, which potentially opens an alternative paradigm to stimulate endogenous peripheral nerve repair.
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5
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Lee SJ, Zhu W, Heyburn L, Nowicki M, Harris B, Zhang LG. Development of Novel 3-D Printed Scaffolds With Core-Shell Nanoparticles for Nerve Regeneration. IEEE Trans Biomed Eng 2017; 64:408-418. [DOI: 10.1109/tbme.2016.2558493] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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6
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Sugimura-Wakayama Y, Katagiri W, Osugi M, Kawai T, Ogata K, Sakaguchi K, Hibi H. Peripheral Nerve Regeneration by Secretomes of Stem Cells from Human Exfoliated Deciduous Teeth. Stem Cells Dev 2015; 24:2687-99. [PMID: 26154068 DOI: 10.1089/scd.2015.0104] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Peripheral nerve regeneration across nerve gaps is often suboptimal, with poor functional recovery. Stem cell transplantation-based regenerative therapy is a promising approach for axon regeneration and functional recovery of peripheral nerve injury; however, the mechanisms remain controversial and unclear. Recent studies suggest that transplanted stem cells promote tissue regeneration through a paracrine mechanism. We investigated the effects of conditioned media derived from stem cells from human exfoliated deciduous teeth (SHED-CM) on peripheral nerve regeneration. In vitro, SHED-CM-treated Schwann cells exhibited significantly increased proliferation, migration, and the expression of neuron-, extracellular matrix (ECM)-, and angiogenesis-related genes. SHED-CM stimulated neuritogenesis of dorsal root ganglia and increased cell viability. Similarly, SHED-CM enhanced tube formation in an angiogenesis assay. In vivo, a 10-mm rat sciatic nerve gap model was bridged by silicon conduits containing SHED-CM or serum-free Dulbecco's modified Eagle's medium. Light and electron microscopy confirmed that the number of myelinated axons and axon-to-fiber ratio (G-ratio) were significantly higher in the SHED-CM group at 12 weeks after nerve transection surgery. The sciatic functional index (SFI) and gastrocnemius (target muscle) wet weight ratio demonstrated functional recovery. Increased compound muscle action potentials and increased SFI in the SHED-CM group suggested sciatic nerve reinnervation of the target muscle and improved functional recovery. We also observed reduced muscle atrophy in the SHED-CM group. Thus, SHEDs may secrete various trophic factors that enhance peripheral nerve regeneration through multiple mechanisms. SHED-CM may therefore provide a novel therapy that creates a more desirable extracellular microenvironment for peripheral nerve regeneration.
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Affiliation(s)
- Yukiko Sugimura-Wakayama
- 1 Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine , Nagoya, Japan
| | - Wataru Katagiri
- 1 Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine , Nagoya, Japan
| | - Masashi Osugi
- 1 Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine , Nagoya, Japan
| | - Takamasa Kawai
- 1 Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine , Nagoya, Japan
| | - Kenichi Ogata
- 1 Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine , Nagoya, Japan .,2 Section of Oral and Maxillofacial Oncology, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University , Fukuoka, Japan
| | - Kohei Sakaguchi
- 1 Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine , Nagoya, Japan
| | - Hideharu Hibi
- 1 Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine , Nagoya, Japan
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7
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Jin H, Yang Q, Ji F, Zhang YJ, Zhao Y, Luo M. Human amniotic epithelial cell transplantation for the repair of injured brachial plexus nerve: evaluation of nerve viscoelastic properties. Neural Regen Res 2015; 10:260-5. [PMID: 25883625 PMCID: PMC4392674 DOI: 10.4103/1673-5374.152380] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/20/2015] [Indexed: 12/11/2022] Open
Abstract
The transplantation of embryonic stem cells can effectively improve the creeping strength of nerves near an injury site in animals. Amniotic epithelial cells have similar biological properties as embryonic stem cells; therefore, we hypothesized that transplantation of amniotic epithelial cells can repair peripheral nerve injury and recover the creeping strength of the brachial plexus nerve. In the present study, a brachial plexus injury model was established in rabbits using the C6 root avulsion method. A suspension of human amniotic epithelial cells was repeatedly injected over an area 4.0 mm lateral to the cephal and caudal ends of the C6 brachial plexus injury site (1 × 106 cells/mL, 3 μL/injection, 25 injections) immediately after the injury. The results showed that the decrease in stress and increase in strain at 7,200 seconds in the injured rabbit C6 brachial plexus nerve were mitigated by the cell transplantation, restoring the viscoelastic stress relaxation and creep properties of the brachial plexus nerve. The forepaw functions were also significantly improved at 26 weeks after injury. These data indicate that transplantation of human amniotic epithelial cells can effectively restore the mechanical properties of the brachial plexus nerve after injury in rabbits and that viscoelasticity may be an important index for the evaluation of brachial plexus injury in animals.
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Affiliation(s)
- Hua Jin
- Jinan Maternity and Child Care Hospital, Jinan, Shandong Province, China
| | - Qi Yang
- China-Japan Union Hospital, Jilin University, Changchun, Jilin Province, China
| | - Feng Ji
- Shandong Corps Hospital of Chinese People's Armed Police Forces, Jinan, Shandong Province, China
| | - Ya-Jie Zhang
- Jinan Maternity and Child Care Hospital, Jinan, Shandong Province, China
| | - Yan Zhao
- Jinan Maternity and Child Care Hospital, Jinan, Shandong Province, China
| | - Min Luo
- China-Japan Union Hospital, Jilin University, Changchun, Jilin Province, China
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8
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Potter-Baker KA, Ravikumar M, Burke AA, Meador WD, Householder KT, Buck AC, Sunil S, Stewart WG, Anna JP, Tomaszewski WH, Capadona JR. A comparison of neuroinflammation to implanted microelectrodes in rat and mouse models. Biomaterials 2014; 35:5637-46. [PMID: 24755527 PMCID: PMC4071936 DOI: 10.1016/j.biomaterials.2014.03.076] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 03/27/2014] [Indexed: 12/31/2022]
Abstract
Rat models have emerged as a common tool to study neuroinflammation to intracortical microelectrodes. While a number of studies have attempted to understand the factors resulting in neuroinflammation using rat models, a complete understanding of key mechanistic pathways remains elusive. Transgenic mouse models, however, could facilitate a deeper understanding of mechanistic pathways due to an ease of genetic alteration. Therefore, the goal of the present study is to compare neuroinflammation following microelectrode implantation between the rat and the mouse model. Our study suggests that subtle differences in the classic neuroinflammatory markers exist between the animal models at both two and sixteen weeks post implantation. Most notably, neuronal densities surrounding microelectrodes were significantly lower in the rat model at two weeks, while similar densities were observed between the animal models at sixteen weeks. Physiological differences between the species and slight alterations in surgical methods are likely key contributors to the observed differences. Moving forward, we propose that differences in the time course of neuroinflammation between the animal models should be considered when trying to understand and prevent intracortical microelectrode failure.
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Affiliation(s)
- Kelsey A Potter-Baker
- Department of Biomedical Engineering, Case Western Reserve University, 2071 Martin Luther King Jr. Drive, Wickenden Bldg., Cleveland, OH 44106, USA; Advanced Platform Technology Center, L. Stokes Cleveland VA Medical Center, 10701 East Blvd. Mail Stop 151 AW/APT, Cleveland, OH 44106-1702, USA
| | - Madhumitha Ravikumar
- Department of Biomedical Engineering, Case Western Reserve University, 2071 Martin Luther King Jr. Drive, Wickenden Bldg., Cleveland, OH 44106, USA; Advanced Platform Technology Center, L. Stokes Cleveland VA Medical Center, 10701 East Blvd. Mail Stop 151 AW/APT, Cleveland, OH 44106-1702, USA
| | - Alan A Burke
- Department of Biomedical Engineering, Case Western Reserve University, 2071 Martin Luther King Jr. Drive, Wickenden Bldg., Cleveland, OH 44106, USA
| | - William D Meador
- Department of Biomedical Engineering, Case Western Reserve University, 2071 Martin Luther King Jr. Drive, Wickenden Bldg., Cleveland, OH 44106, USA
| | - Kyle T Householder
- Department of Biomedical Engineering, Case Western Reserve University, 2071 Martin Luther King Jr. Drive, Wickenden Bldg., Cleveland, OH 44106, USA; Advanced Platform Technology Center, L. Stokes Cleveland VA Medical Center, 10701 East Blvd. Mail Stop 151 AW/APT, Cleveland, OH 44106-1702, USA
| | - Amy C Buck
- Department of Biomedical Engineering, Case Western Reserve University, 2071 Martin Luther King Jr. Drive, Wickenden Bldg., Cleveland, OH 44106, USA; Advanced Platform Technology Center, L. Stokes Cleveland VA Medical Center, 10701 East Blvd. Mail Stop 151 AW/APT, Cleveland, OH 44106-1702, USA
| | - Smrithi Sunil
- Department of Biomedical Engineering, Case Western Reserve University, 2071 Martin Luther King Jr. Drive, Wickenden Bldg., Cleveland, OH 44106, USA; Advanced Platform Technology Center, L. Stokes Cleveland VA Medical Center, 10701 East Blvd. Mail Stop 151 AW/APT, Cleveland, OH 44106-1702, USA
| | - Wade G Stewart
- Department of Biomedical Engineering, Case Western Reserve University, 2071 Martin Luther King Jr. Drive, Wickenden Bldg., Cleveland, OH 44106, USA
| | - Jake P Anna
- Department of Biomedical Engineering, Case Western Reserve University, 2071 Martin Luther King Jr. Drive, Wickenden Bldg., Cleveland, OH 44106, USA
| | - William H Tomaszewski
- Department of Biomedical Engineering, Case Western Reserve University, 2071 Martin Luther King Jr. Drive, Wickenden Bldg., Cleveland, OH 44106, USA
| | - Jeffrey R Capadona
- Department of Biomedical Engineering, Case Western Reserve University, 2071 Martin Luther King Jr. Drive, Wickenden Bldg., Cleveland, OH 44106, USA; Advanced Platform Technology Center, L. Stokes Cleveland VA Medical Center, 10701 East Blvd. Mail Stop 151 AW/APT, Cleveland, OH 44106-1702, USA.
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9
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Sarker MMH, Zhou MC, Rameshwar P, Hanover JA. Functions and roles of a protein-associated factor. Cell Biochem Biophys 2014; 68:577-82. [PMID: 24036680 PMCID: PMC6402795 DOI: 10.1007/s12013-013-9743-0] [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] [Indexed: 10/26/2022]
Abstract
The divergence of protein (Hedgehog) in different organisms remains an unresolved issue to comprehend how the pathway in Hh signaling evolves. Insights into this question can help one identify the key molecules in Hh signaling. This work proposes a protein-associated factor in cells. The development of a non-reductionist theory of cellular functions in medicine is not sufficient. It is necessary to find the parameters with regards to molecules/genes that can elicit functions. This work shows that molecular interactions of gene products can be accomplished by biophysics logic. Defining the protein-associated factors in molecular activities and identifying its roles in molecular transduction are important. A misregulation in molecular switch can account for complex biomolecular consequences. This work shows the potential of the factor on homo-sapiens and unlocks its implications to gene multi-tasking functionality. The associated factor notion should facilitate the medical development in cancer therapeutics.
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Affiliation(s)
- Md Mosharrof Hossain Sarker
- Department of Electrical and Computer Engineering, New Jersey Institute of Technology, Newark, NJ, 07102, USA,
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10
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Mokarram N, Bellamkonda RV. A perspective on immunomodulation and tissue repair. Ann Biomed Eng 2013; 42:338-51. [PMID: 24297492 DOI: 10.1007/s10439-013-0941-0] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 11/12/2013] [Indexed: 12/14/2022]
Abstract
An immune response involves the action of all types of macrophages, classically activated subtype (M1) in the early inflammatory phase and regulatory and wound-healing subtypes (M2) in the resolution phase. The remarkable plasticity of macrophages makes them an interesting target in the context of immunomodulation. Here, we reviewed the current state of understanding regarding the role that different phenotypes of macrophages and monocytes play following injury and during the course of remodeling in different tissue types. Moreover, we explored recent designs of macrophage modulatory biomaterials for tissue engineering and regenerative medicine applications.
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Affiliation(s)
- Nassir Mokarram
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
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11
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Effect of modulating macrophage phenotype on peripheral nerve repair. Biomaterials 2012; 33:8793-801. [PMID: 22979988 DOI: 10.1016/j.biomaterials.2012.08.050] [Citation(s) in RCA: 248] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 08/22/2012] [Indexed: 12/15/2022]
Abstract
Peripheral nerve repair across long gaps remains clinically challenging despite progress made with autograft transplantation. While scaffolds that present trophic factors and extracellular matrix molecules have been designed, matching the performance of autograft-induced repair has been challenging. In this study, we explored the effect of cytokine mediated 'biasing' of macrophage phenotypes on Schwann cell (SC) migration and axonal regeneration in vitro and in vivo. Macrophage phenotype was successfully modulated by local delivery of either Interferon-gamma (IFN-γ) or Interleukin-4 (IL-4) within polymeric nerve guidance channels, polarizing them toward pro-inflammatory (M1) or pro-healing (M2a and M2c) phenotypes, respectively. The initial polarization of macrophages to M2a and M2c phenotype results in enhanced SC infiltration and substantially faster axonal growth in a critically-sized rat sciatic nerve gap model (15 mm). The ratio of pro-healing to pro-inflammatory population of macrophages (CD206+/CCR7+), defined as regenerative bias, demonstrates a linear relationship with the number of axons at the distal end of the nerve scaffolds. The present results clearly suggest that rather than the extent of macrophage presence, their specific phenotype at the site of injury regulates the regenerative outcomes.
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12
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Potter KA, Buck AC, Self WK, Capadona JR. Stab injury and device implantation within the brain results in inversely multiphasic neuroinflammatory and neurodegenerative responses. J Neural Eng 2012; 9:046020. [PMID: 22832283 DOI: 10.1088/1741-2560/9/4/046020] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
An estimated 25 million people in the US alone rely on implanted medical devices, ∼2.5 million implanted within the nervous system. Even though many devices perform adequately for years, the host response to medical devices often severely limits tissue integration and long-term performance. This host response is believed to be particularly limiting in the case of intracortical microelectrodes, where it has been shown that glial cell encapsulation and localized neuronal cell loss accompany intracortical microelectrode implantation. Since neuronal ensembles must be within ∼50 µm of the electrode to obtain neuronal spikes and local field potentials, developing a better understanding of the molecular and cellular environment at the device-tissue interface has been the subject of significant research. Unfortunately, immunohistochemical studies of scar maturation in correlation to device function have been inconclusive. Therefore, here we present a detailed quantitative study of the cellular events and the stability of the blood-brain barrier (BBB) following intracortical microelectrode implantation and cortical stab injury in a chronic survival model. We found two distinctly inverse multiphasic profiles for neuronal survival in device-implanted tissue compared to stab-injured animals. For chronically implanted animals, we observed a biphasic paradigm between blood-derived/trauma-induced and CNS-derived inflammatory markers driving neurodegeneration at the interface. In contrast, stab injured animals demonstrated a CNS-mediated neurodegenerative environment. Collectively these data provide valuable insight to the possibility of multiple roles of chronic neuroinflammatory events on BBB disruption and localized neurodegeneration, while also suggesting the importance to consider multiphasic neuroinflammatory kinetics in the design of therapeutic strategies for stabilizing neural interfaces.
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Affiliation(s)
- Kelsey A Potter
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
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