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Marciante AB, Tadjalli A, Burrowes KA, Oberto JR, Luca EK, Seven YB, Nikodemova M, Watters JJ, Baker TL, Mitchell GS. Microglia regulate motor neuron plasticity via reciprocal fractalkine/adenosine signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.07.592939. [PMID: 38765982 PMCID: PMC11100694 DOI: 10.1101/2024.05.07.592939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Microglia are innate CNS immune cells that play key roles in supporting key CNS functions including brain plasticity. We now report a previously unknown role for microglia in regulating neuroplasticity within spinal phrenic motor neurons, the neurons driving diaphragm contractions and breathing. We demonstrate that microglia regulate phrenic long-term facilitation (pLTF), a form of respiratory memory lasting hours after repetitive exposures to brief periods of low oxygen (acute intermittent hypoxia; AIH) via neuronal/microglial fractalkine signaling. AIH-induced pLTF is regulated by the balance between competing intracellular signaling cascades initiated by serotonin vs adenosine, respectively. Although brainstem raphe neurons release the relevant serotonin, the cellular source of adenosine is unknown. We tested a model in which hypoxia initiates fractalkine signaling between phrenic motor neurons and nearby microglia that triggers extracellular adenosine accumulation. With moderate AIH, phrenic motor neuron adenosine 2A receptor activation undermines serotonin-dominant pLTF; in contrast, severe AIH drives pLTF by a unique, adenosine-dominant mechanism. Phrenic motor neuron fractalkine knockdown, cervical spinal fractalkine receptor inhibition on nearby microglia, and microglial depletion enhance serotonin-dominant pLTF with moderate AIH but suppress adenosine-dominant pLTF with severe AIH. Thus, microglia play novel functions in the healthy spinal cord, regulating hypoxia-induced neuroplasticity within the motor neurons responsible for breathing.
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Affiliation(s)
- Alexandria B. Marciante
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Arash Tadjalli
- Current Address: Nova Southeastern University, College of Allopathic Medicine (NSU MD), Department of Medical Education, 3200 South University Drive, Fort Lauderdale, FL 33328-2018
| | - Kayla A. Burrowes
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Jose R. Oberto
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Edward K. Luca
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Yasin B. Seven
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Maria Nikodemova
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Jyoti J. Watters
- Current Address: Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53706
| | - Tracy L. Baker
- Current Address: Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53706
| | - Gordon S. Mitchell
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
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Spinal Canal and Spinal Cord in Rat Continue to Grow Even after Sexual Maturation: Anatomical Study and Molecular Proposition. Int J Mol Sci 2022; 23:ijms232416076. [PMID: 36555713 PMCID: PMC9781254 DOI: 10.3390/ijms232416076] [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: 11/06/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Although rodents have been widely used for experimental models of spinal cord diseases, the details of the growth curves of their spinal canal and spinal cord, as well as the molecular mechanism of the growth of adult rat spinal cords remain unavailable. They are particularly important when conducting the experiments of cervical spondylotic myelopathy (CSM), since the disease condition depends on the size of the spinal canal and the spinal cord. Thus, the purposes of the present study were to obtain accurate growth curves for the spinal canal and spinal cord in rats; to define the appropriate age in weeks for their use as a CSM model; and to propose a molecular mechanism of the growth of the adult spinal cord in rats. CT myelography was performed on Lewis rats from 4 weeks to 40 weeks of age. The vertical growth of the spinal canal at C5 reached a plateau after 20 and 12 weeks, and at T8 after 20 and 16 weeks, in males and females, respectively. The vertical growth of the C5 and T8 spinal cord reached a plateau after 24 weeks in both sexes. The vertical space available for the cord (SAC) of C5 and T8 did not significantly change after 8 weeks in either sex. Western blot analyses showed that VEGFA, FGF2, and BDNF were highly expressed in the cervical spinal cords of 4-week-old rats, and that the expression of these growth factors declined as rats grew. These findings indicate that the spinal canal and the spinal cord in rats continue to grow even after sexual maturation and that rats need to be at least 8 weeks of age for use in experimental models of CSM. The present study, in conjunction with recent evidence, proposes the hypothetical model that the growth of rat spinal cord after the postnatal period is mediated at least in part by differentiation of neural progenitor cells and that their differentiation potency is maintained by VEGFA, FGF2, and BDNF.
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Sadeghinezhad J, Nyengaard JR. Morphometry of cervical spinal cord in cat using design-based stereology. Anat Histol Embryol 2021; 50:746-755. [PMID: 34137069 DOI: 10.1111/ahe.12719] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 05/18/2021] [Accepted: 05/23/2021] [Indexed: 11/30/2022]
Abstract
The spinal cord harbours nerve fibres that facilitate reflex actions and that transmit impulses to and from the brain. The cervical spinal cord is an area of particular interest in medicine and veterinary due to frequent pathologic alterations in this region. This study describes the morphometric features of the cervical spinal cord in cat using design-unbiased stereological methods. The cervical spinal cords of four male cats were dissected and samples were taken according to systematic uniform random sampling. Each sample was embedded in agar and cut into 60-µm thick sections and stained with cresyl violet 0.1% for stereological estimations. The total cervical spinal cord volume obtained by the Cavalieri estimator was 2,321.21 ± 285.5 mm3 . The relative volume of grey matter and white matter was 23.8 ± 1.3% and 76.1 ± 1.3%. The dorsal horn and ventral horn volume were 12.3 ± 1.2% and 11.4 ± 0.7% of the whole cervical spinal cord. The volume of central canal was estimated to 3.8 ± 1 mm3 . The total number of neurons was accounted 3,405,366.2 ± 267,469.4 using the optical disector/fractionator method. The number of motoneurons and interneurons was estimated to be 1,120,433.2 ± 174,796.7 and 2,284,932.9 ± 127,261.5, respectively. The average volume of the motoneurons and interneurons was estimated to 1980 µm3 and 680 µm3 , respectively, using the spatial rotator method. This knowledge of cat spinal cord findings may serve as a foundation as a translational model in spinal cord experimental research and provide basic findings for diagnosis and treatment of spinal cord disorders.
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Affiliation(s)
- Javad Sadeghinezhad
- Department of Basic Sciences, Faculty of veterinary Medicine, University of Tehran, Tehran, Iran
| | - Jens Randel Nyengaard
- Core Centre for Molecular Morphology, Section for Stereology and Microscopy, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Pathology, Aarhus University Hospital, Aarhus, Denmark
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Gao Y, Vijayaraghavalu S, Stees M, Kwon BK, Labhasetwar V. Evaluating accessibility of intravenously administered nanoparticles at the lesion site in rat and pig contusion models of spinal cord injury. J Control Release 2019; 302:160-168. [PMID: 30930216 DOI: 10.1016/j.jconrel.2019.03.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 03/13/2019] [Accepted: 03/27/2019] [Indexed: 01/17/2023]
Abstract
In spinal cord injury (SCI), timely therapeutic intervention is critical to inhibit the post-injury rapidly progressing degeneration of spinal cord. Towards that objective, we determined the accessibility of intravenously administered biodegradable nanoparticles (NPs) as a drug delivery system to the lesion site in rat and pig contusion models of SCI. Poly (d,l-lactide co-glycolide, PLGA)-based NPs loaded with a near-infrared dye as a marker for NPs were used. To analyze and quantify localization of NPs to the lesion site, we mapped the entire spinal cord, segment-by-segment, for the signal count. Our objectives were to determine the NP dose effect and duration of retention of NPs at the lesion site, and the time window post-SCI within which NPs localize at the lesion site. We hypothesized that breakdown of the blood-spinal cord barrier following contusion injury could lead to more specific localization of NPs at the lesion site. The mapping data showed a dose-dependent increase and significantly greater localization of NPs at the lesion site than in the remaining uninjured segment of the spinal cord. Further, NPs were seen to be retained at the lesion site for more than a week. With delayed post-SCI administration, localization of NPs at the lesion site was reduced but still localize even at four weeks post-injury administration. Interestingly, in uninjured animals (sham control), greater accumulation of NPs was seen in the thoracic and lumbar enlargement regions of the spinal cord, which in animals with SCI changed to the lesion site, indicating drastic post-injury hemodynamic changes in the spinal cord. Similar to the rat results, pig contusion model of SCI showed greater NP localization at the lesion site. In conclusion, NPs could potentially be explored as a carrier for delivery of therapeutics to the lesion site to minimize the impact of post-SCI response.
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Affiliation(s)
- Yue Gao
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Sivakumar Vijayaraghavalu
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Melinda Stees
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Brian K Kwon
- Department of Orthopedics, International Collaboration of Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada
| | - Vinod Labhasetwar
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
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Azizi F, Jalil H, Nasiri Z, Moshtaghian J, Esmaeili F, Doostmohammadi A, Shabani L, Ebrahimie E. The combined effects of three-dimensional cell culture and natural tissue extract on neural differentiation of P19 embryonal carcinoma stem cells. J Tissue Eng Regen Med 2018; 12:1909-1924. [PMID: 29905008 DOI: 10.1002/term.2712] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 05/23/2018] [Accepted: 06/01/2018] [Indexed: 11/10/2022]
Abstract
Tissue engineering, as a novel transplantation therapy, aims to create biomaterial scaffolds resembling the extracellular matrix in order to regenerate the damaged tissues. Adding bioactive factors to the scaffold would improve cell-tissue interactions. In this study, the effect of chitosan polyvinyl alcohol nanofibres containing carbon nanotube scaffold with or without active bioglass (BG+ /BG- ), in combination with neonatal rat brain extract on cell viability, proliferation, and neural differentiation of P19 embryonic carcinoma stem cells was investigated. To induce differentiation, the cells were cultured in α-MEM supplemented with neonatal rat brain extract on the scaffolds. The expression of undifferentiated stem cell markers as well as neuroepithelial and neural-specific markers was evaluated and confirmed by real-time Reverse transcription polymerase chain reaction (RT-PCR) and immunofluorescence procedures. Finally, the three-dimensional (3D) cultured cells were implanted into the damaged neural tubes of chick embryos, and their fates were followed in ovo. Based on the histological and immunofluorescence observations, the transplanted cells were able to survive, migrate, and penetrate into the host embryonic tissues. Gene network analysis suggested the possible involvement of neurotransmitters as a downstream target of synaptophysin and tyrosine hydroxylase. Overall, the results of this study indicated that combining the effects of 3D cell culture and natural brain tissue extract can accelerate the differentiation of P19 embryonic carcinoma cells into neuronal phenotype cells.
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Affiliation(s)
- Faezeh Azizi
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, Iran
| | - Hamidreza Jalil
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, Iran
| | - Zohreh Nasiri
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, Iran
| | - Jamal Moshtaghian
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, Iran
| | - Fariba Esmaeili
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, Iran
| | - Ali Doostmohammadi
- Department of Materials, Faculty of Engineering, Shahrekord University, Shahrekord, Iran
| | - Leila Shabani
- Department of Biology, Faculty of Sciences, Shahrekord University, Shahrekord, Iran
| | - Esmaeil Ebrahimie
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,School of Information Technology and Mathematical Sciences, Division of Information Technology, Engineering and the Environment, University of South Australia, Adelaide, SA, Australia.,Institute of Biotechnology, Shiraz University, Shiraz, Iran.,School of Biological Sciences, Faculty of Science and Engineering, Flinders University, Adelaide, SA, Australia
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Nishida F, Zanuzzi CN, Martínez A, Barbeito CG, Portiansky EL. Functional and histopathological changes induced by intraparenchymal injection of kainic acid in the rat cervical spinal cord. Neurotoxicology 2015; 49:68-78. [PMID: 26014486 DOI: 10.1016/j.neuro.2015.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 04/27/2015] [Accepted: 05/12/2015] [Indexed: 01/04/2023]
Abstract
Kainic acid (KA) is an analog of the neurotransmitter glutamate and is widely used as an excitotoxic agent to lesion spinal cord networks, thus, providing an interesting model to learn basic mechanisms of spinal cord injury. The present work was aimed to evaluate motor and sensory performance of rats and analyze morphometric parameters of spinal cord neurons after KA injection. Animals were injected either with 0.75, 1 or 1.25 mM of KA at the C5 segment of the cervical spinal cord. Motor and sensory performance of the rats were evaluate at day 0 (before injection) and at days 1, 2, 3 and 7 post-injection (pi) and compared with those of saline-treated and non-operated animals. Animals were sacrificed at each time point for morphometric and histopathological analysis and compared among groups. All KA-treated animals showed a significant impairment at the motor and sensory tests for the ipsilateral forelimb in a concentration-dependent manner in comparison to saline-treated and non-operated animals. Neuronal cell count showed a significant loss of neurons at C4, C5 and C6 cervical segments when compared with those of saline-treated and non-operated animals. The contralateral side of the cervical segments in KA-treated rats remained unchanged. Some improvement at the motor and sensory tests was observed in animals injected with 0.75 and 1mM KA. Moreover, a mild increase in the neuronal count of the damaged segments was also recorded. The improvement recorded in the motor and sensory tests by day 7 pi may be a consequence of a neuron repairing mechanism triggered soon after the KA excitotoxic effect.
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Affiliation(s)
- Fabián Nishida
- Image Analysis Laboratory, School of Veterinary Sciences, National University of La Plata (UNLP), Buenos Aires, Argentina; National Research Council of Science and Technology (CONICET), Argentina.
| | - Carolina N Zanuzzi
- Image Analysis Laboratory, School of Veterinary Sciences, National University of La Plata (UNLP), Buenos Aires, Argentina; Department of Histology and Embryology, School of Veterinary Sciences, National University of La Plata, Buenos Aires, Argentina; National Research Council of Science and Technology (CONICET), Argentina.
| | - Agustín Martínez
- National Institute of Agricultural Technology (INTA), Bariloche, Argentina.
| | - Claudio G Barbeito
- Image Analysis Laboratory, School of Veterinary Sciences, National University of La Plata (UNLP), Buenos Aires, Argentina; Department of Histology and Embryology, School of Veterinary Sciences, National University of La Plata, Buenos Aires, Argentina; National Research Council of Science and Technology (CONICET), Argentina.
| | - Enrique L Portiansky
- Image Analysis Laboratory, School of Veterinary Sciences, National University of La Plata (UNLP), Buenos Aires, Argentina; National Research Council of Science and Technology (CONICET), Argentina.
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Is the vertebral canal prepared to host the aged spinal cord? A morphometric assessment. ZOOMORPHOLOGY 2014. [DOI: 10.1007/s00435-013-0215-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Kennedy HS, Jones C, Caplazi P. Comparison of standard laminectomy with an optimized ejection method for the removal of spinal cords from rats and mice. J Histotechnol 2013; 36:86-91. [PMID: 24039319 PMCID: PMC3770983 DOI: 10.1179/014788813x13756994210382] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
For researchers seeking to collect spinal cord samples from mice and rats while avoiding acid decalcification, few options are available. Laminectomy is the standard method which yields high quality samples, yet is time consuming and technically difficult. Ejection of the cord from the vertebral column is another technique commonly used; however, the literature suggests that this method can damage the spinal tissues and is typically avoided when histology of samples is the desired endpoint. Here, we describe an optimized method for ejection of spinal cords from rats and mice, and compare histological quality of these samples with those collected via laminectomy. Our results show that ejection can yield high quality spinal cord samples and may be suitable for use as an alternative to laminectomy.
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Affiliation(s)
- Heather S Kennedy
- Genentech, Inc., 1 DNA Way, MS 462a, South San Francisco, CA, California, USA
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