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Riew TR, Hwang JW, Jin X, Kim HL, Jung SJ, Lee MY. Astrocytes are involved in the formation of corpora amylacea-like structures from neuronal debris in the CA1 region of the rat hippocampus after ischemia. Front Cell Neurosci 2023; 17:1308247. [PMID: 38188667 PMCID: PMC10766773 DOI: 10.3389/fncel.2023.1308247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 12/04/2023] [Indexed: 01/09/2024] Open
Abstract
Recently, we demonstrated that the corpora amylacea (CA), a glycoprotein-rich aggregate frequently found in aged brains, accumulates in the ischemic hippocampus and that osteopontin (OPN) mediates the entire process of CA formation. Therefore, this study aimed to elucidate the mechanisms by which astrocytes and microglia participate in CA formation during the late phase (4-12 weeks) of brain ischemia. Based on various morphological analyses, including immunohistochemistry, in situ hybridization, immunoelectron microscopy, and correlative light and electron microscopy, we propose that astrocytes are the primary cells responsible for CA formation after ischemia. During the subacute phase after ischemia, astrocytes, rather than microglia, express Opn messenger ribonucleic acid and OPN protein, a surrogate marker and key component of CA. Furthermore, the specific localization of OPN in the Golgi complex suggests that it is synthesized and secreted by astrocytes. Astrocytes were in close proximity to type I OPN deposits, which accumulated in the mitochondria of degenerating neurons before fully forming the CA (type III OPN deposits). Throughout CA formation, astrocytes remained closely attached to OPN deposits, with their processes exhibiting well-developed gap junctions. Astrocytic cytoplasmic protein S100β, a calcium-binding protein, was detected within the fully formed CA. Additionally, ultrastructural analysis revealed direct contact between astroglial fibrils and the forming facets of the CA. Overall, we demonstrated that astrocytes play a central role in mediating CA formation from the initial stages of OPN deposit accumulation to the evolution of fully formed CA following transient ischemia in the hippocampus.
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Affiliation(s)
- Tae-Ryong Riew
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
- Department of Biomedicine and Health Sciences, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Ji-Won Hwang
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
- Department of Biomedicine and Health Sciences, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Xuyan Jin
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
- Department of Biomedicine and Health Sciences, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Hong Lim Kim
- Integrative Research Support Center, Laboratory of Electron Microscope, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Sharon Jiyoon Jung
- Technological Convergence Center, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
| | - Mun-Yong Lee
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
- Department of Biomedicine and Health Sciences, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
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Zhang H, Lu Y, Kramer PR, Benson MD, Cheng YSL, Qin C. Intracranial calcification in Fam20c-deficient mice recapitulates human Raine syndrome. Neurosci Lett 2023; 802:137176. [PMID: 36914045 DOI: 10.1016/j.neulet.2023.137176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/26/2023] [Accepted: 03/08/2023] [Indexed: 03/15/2023]
Abstract
FAM20C (family with sequence similarity 20-member C) is a protein kinase that phosphorylates secretory proteins, including the proteins that are essential to the formation and mineralization of calcified tissues. FAM20C loss-of-function mutations cause Raine syndrome in humans, characterized by generalized osteosclerosis, distinctive craniofacial dysmorphism, along with extensive intracranial calcification. Our previous studies revealed that inactivation of Fam20c in mice led to hypophosphatemic rickets. In this study, we examined the expression of Fam20c in the mouse brain and investigated brain calcification in Fam20c-deficient mice. Reverse transcription polymerase chain reaction (RT-PCR), Western-blotting and in situ hybridization analyses demonstrated the broad expression of Fam20c in the mouse brain tissue. X-ray and histological analyses showed that the global deletion of Fam20c (mediated by Sox2-cre) resulted in brain calcification in mice after postnatal 3 months and that the calcifications were bilaterally distributed within the brain. There was mild perifocal microgliosis as well as astrogliosis around calcospherites. The calcifications were first observed in the thalamus, and later in the forebrain and hindbrain. Furthermore, brain-specific deletion (mediated by Nestin-cre) of Fam20c in mice also led to cerebral calcification at an older age (postnatal 6 months), but no obvious skeletal or dental defects. Our results suggest that the local loss of FAM20C function in the brain may directly account for intracranial calcification. We propose that FAM20C plays an essential role in maintaining normal brain homeostasis and preventing ectopic brain calcification.
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Affiliation(s)
- Hua Zhang
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, Dallas, TX 75246, USA.
| | - Yongbo Lu
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, Dallas, TX 75246, USA
| | - Phillip R Kramer
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, Dallas, TX 75246, USA
| | - M Douglas Benson
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, Dallas, TX 75246, USA
| | - Yi-Shing L Cheng
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, Dallas, TX 75246, USA
| | - Chunlin Qin
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, Dallas, TX 75246, USA
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West PK, Viengkhou B, Campbell IL, Hofer MJ. Microglia shield the murine brain from damage mediated by the cytokines IL-6 and IFN-α. Front Immunol 2022; 13:1036799. [PMID: 36389783 PMCID: PMC9650248 DOI: 10.3389/fimmu.2022.1036799] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 10/13/2022] [Indexed: 12/10/2023] Open
Abstract
Sustained production of elevated levels of the cytokines interleukin (IL)-6 or interferon (IFN)-α in the central nervous system (CNS) is detrimental and directly contributes to the pathogenesis of neurological diseases such as neuromyelitis optica spectrum disorders or cerebral interferonopathies, respectively. Using transgenic mice with CNS-targeted production of IL-6 (GFAP-IL6) or IFN-α (GFAP-IFN), we have recently demonstrated that microglia are prominent target and effector cells and mount stimulus-specific responses to these cytokines. In order to further clarify the phenotype and function of these cells, we treated GFAP-IL6 and GFAP-IFN mice with the CSF1R inhibitor PLX5622 to deplete microglia. We examined their ability to recover from acute microglia depletion, as well as the impact of chronic microglia depletion on the progression of disease. Following acute depletion in the brains of GFAP-IL6 mice, microglia repopulation was enhanced, while in GFAP-IFN mice, microglia did not repopulate the brain. Furthermore, chronic CSF1R inhibition was detrimental to the brain of GFAP-IL6 and GFAP-IFN mice and gave rise to severe CNS calcification which strongly correlated with the absence of microglia. In addition, PLX5622-treated GFAP-IFN mice had markedly reduced survival. Our findings provide evidence for novel microglia functions to protect against IFN-α-mediated neurotoxicity and neuronal dysregulation, as well as restrain calcification as a result of both IL-6- and IFN-α-induced neuroinflammation. Taken together, we demonstrate that CSF1R inhibition may be an undesirable target for therapeutic treatment of neuroinflammatory diseases that are driven by elevated IL-6 and IFN-α production.
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Affiliation(s)
| | | | | | - Markus J. Hofer
- School of Life and Environmental Sciences, Charles Perkins Centre and the Sydney Institute for Infectious Diseases, The University of Sydney, Sydney, NSW, Australia
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4
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Osteopontin mediates the formation of corpora amylacea-like structures from degenerating neurons in the CA1 region of the rat hippocampus after ischemia. Cell Tissue Res 2022; 389:443-463. [PMID: 35688947 DOI: 10.1007/s00441-022-03645-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 05/23/2022] [Indexed: 11/02/2022]
Abstract
We previously demonstrated that osteopontin (OPN) is closely associated with calcium precipitation in response to ischemic brain insults. The present study was designed to elucidate the possible association between deposition of OPN and progressive neurodegeneration in the ischemic hippocampus. To address this, we analyzed the OPN deposits in the rat hippocampus after global cerebral ischemia in the chronic phase (4 to 12 weeks) after reperfusion using immunoelectron microscopy and correlative light and electron microscopy. We identified three different types of OPN deposits based on their morphological characteristics, numbered according to the order in which they evolved. Dark degenerative cells that retained cellular morphology were frequently observed in the pyramidal cell layer, and type I OPN deposits were degenerative mitochondria that accumulated among these cells. Type II deposits evolved into more complex amorphous structures with prominent OPN deposits within their periphery and within degenerative mitochondria-like structures. Finally, type III had large concentric laminated structures with irregularly shaped bodies in the center of the deposits. In all types, OPN expression was closely correlated with calcification, as confirmed by calcium fixation and Alizarin Red staining. Notably, type II and III deposits were highly reminiscent of corpora amylacea, glycoprotein-rich aggregates found in aged brains, or neurodegenerative disease, which was further confirmed by ubiquitin expression and periodic acid-Schiff staining. Overall, our data provide a novel link between ongoing neurodegeneration and the formation of corpora amylacea-like structures and calcium deposits in the ischemic hippocampus, suggesting that OPN may play an important role in such processes.
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Osteopontin accumulates in basal deposits of human eyes with age-related macular degeneration and may serve as a biomarker of aging. Mod Pathol 2022; 35:165-176. [PMID: 34389792 PMCID: PMC8786662 DOI: 10.1038/s41379-021-00887-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/13/2021] [Accepted: 07/14/2021] [Indexed: 11/24/2022]
Abstract
A common clinical phenotype of several neurodegenerative and systemic disorders including Alzheimer's disease and atherosclerosis is the abnormal accumulation of extracellular material, which interferes with routine cellular functions. Similarly, patients with age-related macular degeneration (AMD), the leading cause of vision loss among the aged population, present with extracellular lipid- and protein-filled basal deposits in the back of the eye. While the exact mechanism of growth and formation of these deposits is poorly understood, much has been learned from investigating their composition, providing critical insights into AMD pathogenesis, prevention, and therapeutics. We identified human osteopontin (OPN), a phosphoprotein expressed in a variety of tissues in the body, as a newly discovered component of basal deposits in AMD patients, with a distinctive punctate staining pattern. OPN expression within these lesions, which are associated with AMD disease progression, were found to co-localize with abnormal calcium deposition. Additionally, OPN puncta colocalized with an AMD risk-associated complement pathway protein, but not with apolipoprotein E or vitronectin, two other well-established basal deposit components. Mechanistically, we found that retinal pigment epithelial cells, cells vulnerable in AMD, will secrete OPN into the extracellular space, under oxidative stress conditions, supporting OPN biosynthesis locally within the outer retina. Finally, we report that OPN levels in plasma of aged (non-AMD) human donors were significantly higher than levels in young (non-AMD) donors, but were not significantly different from donors with the different clinical subtypes of AMD. Collectively, our study defines the expression pattern of OPN in the posterior pole as a function of disease, and its local expression as a potential histopathologic biomarker of AMD.
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Brown GC. Neuronal Loss after Stroke Due to Microglial Phagocytosis of Stressed Neurons. Int J Mol Sci 2021; 22:13442. [PMID: 34948237 PMCID: PMC8707068 DOI: 10.3390/ijms222413442] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 11/17/2022] Open
Abstract
After stroke, there is a rapid necrosis of all cells in the infarct, followed by a delayed loss of neurons both in brain areas surrounding the infarct, known as 'selective neuronal loss', and in brain areas remote from, but connected to, the infarct, known as 'secondary neurodegeneration'. Here we review evidence indicating that this delayed loss of neurons after stroke is mediated by the microglial phagocytosis of stressed neurons. After a stroke, neurons are stressed by ongoing ischemia, excitotoxicity and/or inflammation and are known to: (i) release "find-me" signals such as ATP, (ii) expose "eat-me" signals such as phosphatidylserine, and (iii) bind to opsonins, such as complement components C1q and C3b, inducing microglia to phagocytose such neurons. Blocking these factors on neurons, or their phagocytic receptors on microglia, can prevent delayed neuronal loss and behavioral deficits in rodent models of ischemic stroke. Phagocytic receptors on microglia may be attractive treatment targets to prevent delayed neuronal loss after stroke due to the microglial phagocytosis of stressed neurons.
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Affiliation(s)
- Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
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Dashdulam D, Kim ID, Lee H, Lee HK, Kim SW, Lee JK. Osteopontin heptamer peptide containing the RGD motif enhances the phagocytic function of microglia. Biochem Biophys Res Commun 2020; 524:371-377. [PMID: 32005517 DOI: 10.1016/j.bbrc.2020.01.100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 01/16/2020] [Indexed: 12/29/2022]
Abstract
Osteopontin (OPN) is a phosphorylated glycoprotein expressed in various tissues, including brain, and mediates a wide range of cellular activities. In our previous studies, we reported recombinant OPN and RGD and SLAY-containing OPN-peptide icosamer (OPNpt20) exhibited robust neuroprotective activities in an animal model of transient focal ischemia, and attributed these effects to the anti-inflammatory, pro-angiogenic, and phagocytic functions of OPNpt20. In the present study, we truncated OPNpt20 to 13 or 7 amino acid peptides containing RGD (R) and/or SLAY (S) motif (OPNpt13RS, OPNpt7R, OPNpt7RS, and OPNpt7S) and their cell motility and migration inducing activities were examined in BV2 cells (a microglia cell line). All four peptides significantly enhanced BV2 cell motility and migration, but OPNpt7R, an RGD-containing 7-amino-acid OPN peptide (VPNGRGD), was found to be most potent and its potency was comparable to OPNpt20. Phagocytic activity and F-actin polymerization were also significantly enhanced in OPNpt7R-treated BV2 cells. Importantly, studies using two mutant peptides (OPNpt7R-RAA and OPNpt7R-RAD, wherein RGD in OPNpt7R was replaced with RAA or RAD, respectively) revealed that all these effects of OPNpt7R, motility, migration, F-actin polymerization, and phagocytosis induction, were RGD-dependent. Furthermore, the Erk, Fak, and Akt signaling pathways appeared to be involved in the induction of phagocytic activity by OPNpt7R. Co-treating cells with OPNpt7R and D98059 or wortmannin (pharmacological inhibitors of Erk and Akt, respectively) significantly suppressed OPNpt7R-mediated phagocytosis induction. These results indicate the RGD-containing OPN heptamer OPNpt7R triggers microglial motility, migration, and phagocytic activity and that the RGD motif plays a critical role in these activities.
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Affiliation(s)
- Davaanyam Dashdulam
- Department of Anatomy, Inha University School of Medicine, Incheon, Republic of Korea; Medical Research Center, Inha University School of Medicine, Incheon, Republic of Korea
| | - Il-Doo Kim
- Department of Anatomy, Inha University School of Medicine, Incheon, Republic of Korea; Medical Research Center, Inha University School of Medicine, Incheon, Republic of Korea
| | - Hahnbie Lee
- Department of Anatomy, Inha University School of Medicine, Incheon, Republic of Korea; Medical Research Center, Inha University School of Medicine, Incheon, Republic of Korea
| | - Hye-Kyung Lee
- Department of Anatomy, Inha University School of Medicine, Incheon, Republic of Korea; Medical Research Center, Inha University School of Medicine, Incheon, Republic of Korea
| | - Seung-Woo Kim
- Department of Anatomy, Inha University School of Medicine, Incheon, Republic of Korea; Department of Biomedical Sciences, Inha University School of Medicine, Incheon, Republic of Korea
| | - Ja-Kyeong Lee
- Department of Anatomy, Inha University School of Medicine, Incheon, Republic of Korea; Medical Research Center, Inha University School of Medicine, Incheon, Republic of Korea.
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Sugiyama Y, Oishi T, Yamashita A, Murata Y, Yamamoto T, Takashima I, Isa T, Higo N. Neuronal and microglial localization of secreted phosphoprotein 1 (osteopontin) in intact and damaged motor cortex of macaques. Brain Res 2019; 1714:52-64. [PMID: 30790559 DOI: 10.1016/j.brainres.2019.02.021] [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] [Received: 10/02/2018] [Revised: 02/12/2019] [Accepted: 02/17/2019] [Indexed: 01/06/2023]
Abstract
We previously reported that mRNA encoding secreted phosphoprotein 1 (SPP1), also known as osteopontin, is preferentially expressed in large neurons in layer V of the macaque motor cortex, most of which are presumed to be corticospinal tract neurons. As a first step to elucidating the cellular function of SPP1 in macaque neurons, we examined the localization of SPP1 in the primary motor cortex (M1) of the macaque by using immunohistochemistry. SPP1 immunoreactivity was found to be localized in the cell bodies of neurons, but not outside the cells, indicating that SPP1 was not secreted from these neurons. The results of electron microscope analysis and double-labeling analysis with marker proteins suggested that SPP1 was localized in the mitochondria of neurons. The distributions of SPP1 in the neurons corresponded to those of integrin αV, a putative receptor for SPP1. The distribution of SPP1 was also investigated in macaques whose M1 had been lesioned. We found that SPP1 was secreted by proliferated microglia in the lesioned area. Double-labeling analysis indicated that SPP1 immunoreactivity in the microglia was colocalized with CD44, another putative receptor for SPP1. Success rates in the small-object-retrieval task were positively correlated with SPP1 immunoreactivity in the neurons in the perilesional area. SPP1 has multiple roles in the macaque motor cortex, and it may be a key protein during recovery of hand movement after brain damage.
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Affiliation(s)
- Yoko Sugiyama
- Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan; Graduate School of Comprehensive Human Science, University of Tsukuba, Tsukuba, Ibaraki 305-8574, Japan
| | - Takao Oishi
- Systems Neuroscience Section, Primate Research Institute, Kyoto University, Inuyama, Aichi 484-8506, Japan
| | - Akiko Yamashita
- Division of Biology, Department of Liberal Education, Nihon University School of Medicine, Tokyo 173-8610, Japan
| | - Yumi Murata
- Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
| | - Tatsuya Yamamoto
- Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan; Department of Physical Therapy, Faculty of Medical and Health Sciences, Tsukuba International University, Tsuchiura, Ibaraki 300-0051, Japan
| | - Ichiro Takashima
- Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan; Graduate School of Comprehensive Human Science, University of Tsukuba, Tsukuba, Ibaraki 305-8574, Japan
| | - Tadashi Isa
- Department of Neuroscience, Graduate School of Medicine, Kyoto University, Yoshida-konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Noriyuki Higo
- Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan.
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Riew TR, Kim S, Jin X, Kim HL, Lee JH, Lee MY. Osteopontin and its spatiotemporal relationship with glial cells in the striatum of rats treated with mitochondrial toxin 3-nitropropionic acid: possible involvement in phagocytosis. J Neuroinflammation 2019; 16:99. [PMID: 31088570 PMCID: PMC6518780 DOI: 10.1186/s12974-019-1489-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 04/25/2019] [Indexed: 12/16/2022] Open
Abstract
Background Osteopontin (OPN, SPP1) is upregulated in response to acute brain injury, and based on its immunoreactivity, two distinct forms have been identified: intracellular OPN within brain macrophages and small granular OPN, identified as OPN-coated degenerated neurites. This study investigates the spatiotemporal relationship between punctate OPN deposition and astroglial and microglial reactions elicited by 3-nitropropionic acid (3-NP). Methods Male Sprague-Dawley rats were intraperitoneally injected with mitochondrial toxin 3-NP and euthanized at 3, 7, 14, and 28 days. Quantitative and qualitative light and electron microscopic techniques were used to assess the relationship between OPN and glial cells. Statistical significance was determined by Student’s t test or a one-way analysis of variance followed by Tukey’s multiple comparisons test. Results Punctate OPN-immunoreactive profiles were synthesized and secreted by amoeboid-like brain macrophages in the lesion core, but not by reactive astrocytes and activated microglia with a stellate shape in the peri-lesional area. Punctate OPN accumulation was detected only in the lesion core away from reactive astrocytes in the peri-lesional area at day 3, but had direct contact with, and even overlapped with astroglial processes at day 7. The distance between the OPN-positive area and the astrocytic scar significantly decreased from days 3 to 7. By days 14 and 28 post-lesion, when the glial scar was fully formed, punctate OPN distribution mostly overlapped with the astrocytic scar. Three-dimensional reconstructions and quantitative image analysis revealed numerous granular OPN puncta inside the cytoplasm of reactive astrocytes and brain macrophages. Reactive astrocytes showed prominent expression of the lysosomal marker lysosomal-associated membrane protein 1, and ultrastructural analysis confirmed OPN-coated degenerating neurites inside astrocytes, suggesting the phagocytosis of OPN puncta by reactive astrocytes after injury. Conclusions Punctate OPN-immunoreactive profiles corresponded to OPN-coated degenerated neurites, which were closely associated with, or completely engulfed by, the reactive astrocytes forming the astroglial scar in 3-NP lesioned striatum, suggesting that OPN may cause astrocytes to migrate towards these degenerated neurites in the lesion core to establish physical contact with, and possibly, to phagocytose them. Our results provide novel insights essential to understanding the recovery and repair of the central nervous system tissue. Electronic supplementary material The online version of this article (10.1186/s12974-019-1489-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tae-Ryong Riew
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seoul, 06591, Republic of Korea
| | - Soojin Kim
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seoul, 06591, Republic of Korea
| | - Xuyan Jin
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seoul, 06591, Republic of Korea.,Department of Biomedicine and Health Sciences, College of Medicine, The Catholic University of Korea, Seoul, 06591, Republic of Korea
| | - Hong Lim Kim
- Integrative Research Support Center, Laboratory of Electron Microscope, College of Medicine, The Catholic University of Korea, Seoul, 06591, Republic of Korea
| | - Jeong-Hwa Lee
- Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul, 06591, Republic of Korea.,The Institute for Aging and Metabolic Diseases, College of Medicine, The Catholic University of Korea, Seoul, 06591, Republic of Korea
| | - Mun-Yong Lee
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seoul, 06591, Republic of Korea. .,Department of Biomedicine and Health Sciences, College of Medicine, The Catholic University of Korea, Seoul, 06591, Republic of Korea.
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Proangiogenic functions of an RGD-SLAY-containing osteopontin icosamer peptide in HUVECs and in the postischemic brain. Exp Mol Med 2018; 50:e430. [PMID: 29350679 PMCID: PMC5799800 DOI: 10.1038/emm.2017.241] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 07/05/2017] [Accepted: 07/07/2017] [Indexed: 01/08/2023] Open
Abstract
Osteopontin (OPN) is a phosphorylated glycoprotein secreted into body fluids by various cell types. OPN contains arginine-glycine-aspartate (RGD) and serine-leucine-alanine-tyrosine (SLAY) motifs that bind to several integrins and mediate a wide range of cellular processes. In the present study, the proangiogenic effects of a 20-amino-acid OPN peptide (OPNpt20) containing RGD and SLAY motifs were examined in human umbilical vein endothelial cells (HUVECs) and in a rat focal cerebral ischemia model. OPNpt20 exerted robust proangiogenic effects in HUVECs by promoting proliferation, migration and tube formation. These effects were significantly reduced in OPNpt20-RAA (RGD->RAA)-treated cells, but only slightly reduced in OPNpt20-SLAA (SLAY->SLAA)-treated cells. Interestingly, a mutant peptide without both motifs failed to induce these proangiogenic processes, indicating that the RGD motif is crucial and that SLAY also has a role. In OPNpt20-treated HUVEC cultures, AKT and ERK signaling pathways were activated, but activation of these pathways and tube formation were suppressed by anti-αvβ3 antibody, indicating that OPNpt20 stimulates angiogenesis via the αvβ3-integrin/AKT and ERK pathways. The proangiogenic function of OPNpt20 was further confirmed in a rat middle cerebral artery occlusion model. Total vessel length and vessel densities were markedly greater in OPNpt20-treated ischemic brains, accompanied by induction of proangiogenic markers. Together, these results demonstrate that the 20-amino-acid OPN peptide containing RGD and SLAY motifs exerts proangiogenic effects, wherein both motifs have important roles, and these effects appear to contribute to the neuroprotective effects of this peptide in the postischemic brain.
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11
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Riew TR, Kim HL, Jin X, Choi JH, Shin YJ, Kim JS, Lee MY. Spatiotemporal expression of osteopontin in the striatum of rats subjected to the mitochondrial toxin 3-nitropropionic acid correlates with microcalcification. Sci Rep 2017; 7:45173. [PMID: 28345671 PMCID: PMC5366947 DOI: 10.1038/srep45173] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 02/20/2017] [Indexed: 11/18/2022] Open
Abstract
Our aim was to elucidate whether osteopontin (OPN) is involved in the onset of mineralisation and progression of extracellular calcification in striatal lesions due to mitochondrial toxin 3-nitropropionic acid exposure. OPN expression had two different patterns when observed using light microscopy. It was either localised to the Golgi complex in brain macrophages or had a small granular pattern scattered in the affected striatum. OPN labelling tended to increase in number and size over a 2-week period following the lesion. Ultrastructural investigations revealed that OPN is initially localised to degenerating mitochondria within distal dendrites, which were then progressively surrounded by profuse OPN on days 7–14. Electron probe microanalysis of OPN-positive and calcium-fixated neurites indicated that OPN accumulates selectively on the surfaces of degenerating calcifying dendrites, possibly via interactions between OPN and calcium. In addition, 3-dimensional reconstruction of OPN-positive neurites revealed that they are in direct contact with larger OPN-negative degenerating dendrites rather than with fragmented cell debris. Our overall results indicate that OPN expression is likely to correlate with the spatiotemporal progression of calcification in the affected striatum, and raise the possibility that OPN may play an important role in the initiation and progression of microcalcification in response to brain insults.
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Affiliation(s)
- Tae-Ryong Riew
- Department of Anatomy, Catholic Neuroscience Institute, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Hong Lim Kim
- Integrative Research Support Center, Laboratory of Electron Microscope, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Xuyan Jin
- Department of Anatomy, Catholic Neuroscience Institute, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Jeong-Heon Choi
- Department of Anatomy, Catholic Neuroscience Institute, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Yoo-Jin Shin
- Department of Anatomy, Catholic Neuroscience Institute, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Ji Soo Kim
- Gumi Electronics &Information Technology Research Institute, Gumi, Korea
| | - Mun-Yong Lee
- Department of Anatomy, Catholic Neuroscience Institute, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, Seoul, Korea
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Chang SW, Kim HI, Kim GH, Park SJ, Kim IB. Increased Expression of Osteopontin in Retinal Degeneration Induced by Blue Light-Emitting Diode Exposure in Mice. Front Mol Neurosci 2016; 9:58. [PMID: 27504084 PMCID: PMC4958628 DOI: 10.3389/fnmol.2016.00058] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 07/07/2016] [Indexed: 02/01/2023] Open
Abstract
Osteopontin (OPN) is a multifunctional adhesive glycoprotein that is implicated in a variety of pro-inflammatory as well as neuroprotective and repair-promoting effects in the brain. As a first step towards understanding the role of OPN in retinal degeneration (RD), we examined changes in OPN expression in a mouse model of RD induced by exposure to a blue light-emitting diode (LED). RD was induced in BALB/c mice by exposure to a blue LED (460 nm) for 2 h. Apoptotic cell death was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. In order to investigate changes in OPN in RD, western blotting and immunohistochemistry were performed. Anti-OPN labeling was compared to that of anti-glial fibrillary acidic protein (GFAP), which is a commonly used marker for retinal injury or stress including inflammation. OPN expression in RD retinas markedly increased at 24 h after exposure, was sustained through 72 h, and subsided at 120 h. Increased OPN expression was observed co-localized with microglial cells in the outer nuclear layer (ONL), outer plexiform layer (OPL), and subretinal space. Expression was restricted to the central retina in which photoreceptor cell death occurred. Interestingly, OPN expression in the ONL/OPL was closely associated with microglia, whereas most of the OPN plaques observed in the subretinal space were not. Immunogold electron microscopy demonstrated that OPN was distributed throughout the cytoplasm of microglia and in nearby fragments of degenerating photoreceptors. In addition, we found that OPN was induced more acutely and with greater region specificity than GFAP. These results indicate that OPN may be a more useful marker for retinal injury or stress, and furthermore act as a microglial pro-inflammatory mediator and a phagocytosis-inducing opsonin in the subretinal space. Taken together, our data suggest that OPN plays an important role in the pathogenesis of RD.
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Affiliation(s)
- Seung Wook Chang
- Department of Anatomy, College of Medicine, The Catholic University of Korea Seoul, Korea
| | - Hyung Il Kim
- Department of Anatomy, College of Medicine, The Catholic University of KoreaSeoul, Korea; Gyeongju St. Mary's Eye ClinicGyeongju, Korea
| | - Gyu Hyun Kim
- Department of Anatomy, College of Medicine, The Catholic University of KoreaSeoul, Korea; Catholic Neuroscience Institute, College of Medicine, The Catholic University of KoreaSeoul, Korea
| | - Su Jin Park
- Department of Anatomy, College of Medicine, The Catholic University of KoreaSeoul, Korea; Catholic Neuroscience Institute, College of Medicine, The Catholic University of KoreaSeoul, Korea
| | - In-Beom Kim
- Department of Anatomy, College of Medicine, The Catholic University of KoreaSeoul, Korea; Catholic Neuroscience Institute, College of Medicine, The Catholic University of KoreaSeoul, Korea; Catholic Institute for Applied Anatomy, College of Medicine, The Catholic University of KoreaSeoul, Korea
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Riew TR, Shin YJ, Kim HL, Cho JM, Pak HJ, Lee MY. Spatiotemporal Progression of Microcalcification in the Hippocampal CA1 Region following Transient Forebrain Ischemia in Rats: An Ultrastructural Study. PLoS One 2016; 11:e0159229. [PMID: 27414398 PMCID: PMC4945069 DOI: 10.1371/journal.pone.0159229] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 06/29/2016] [Indexed: 11/19/2022] Open
Abstract
Calcification in areas of neuronal degeneration is a common finding in several neuropathological disorders including ischemic insults. Here, we performed a detailed examination of the onset and spatiotemporal profile of calcification in the CA1 region of the hippocampus, where neuronal death has been observed after transient forebrain ischemia. Histopathological examinations showed very little alizarin red staining in the CA1 pyramidal cell layer until day 28 after reperfusion, while prominent alizarin red staining was detected in CA1 dendritic subfields, particularly in the stratum radiatum, by 14 days after reperfusion. Electron microscopy using the osmium/potassium dichromate method and electron probe microanalysis revealed selective calcium deposits within the mitochondria of degenerating dendrites at as early as 7 days after reperfusion, with subsequent complete mineralization occurring throughout the dendrites, which then coalesced to form larger mineral conglomerates with the adjacent calcifying neurites by 14 days after reperfusion. Large calcifying deposits were frequently observed at 28 days after reperfusion, when they were closely associated with or completely engulfed by astrocytes. In contrast, no prominent calcification was observed in the somata of CA1 pyramidal neurons showing the characteristic features of necrotic cell death after ischemia, although what appeared to be calcified mitochondria were noted in some degenerated neurons that became dark and condensed. Thus, our data indicate that intrahippocampal calcification after ischemic insults initially occurs within the mitochondria of degenerating dendrites, which leads to the extensive calcification that is associated with ischemic injuries. These findings suggest that in degenerating neurons, the calcified mitochondria in the dendrites, rather than in the somata, may serve as the nidus for further calcium precipitation in the ischemic hippocampus.
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Affiliation(s)
- Tae-Ryong Riew
- Department of Anatomy, Catholic Neuroscience Institute, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 137-701, Seoul, Korea
| | - Yoo-Jin Shin
- Department of Anatomy, Catholic Neuroscience Institute, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 137-701, Seoul, Korea
| | - Hong Lim Kim
- Integrative Research Support Center, Laboratory of Electron Microscope, College of Medicine, The Catholic University of Korea, Seoul, Korea, 137-701, Seoul, Korea
| | - Jeong Min Cho
- Department of Anatomy, Catholic Neuroscience Institute, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 137-701, Seoul, Korea
| | - Ha-Jin Pak
- Department of Anatomy, Catholic Neuroscience Institute, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 137-701, Seoul, Korea
| | - Mun-Yong Lee
- Department of Anatomy, Catholic Neuroscience Institute, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 137-701, Seoul, Korea
- * E-mail:
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Kim HL, Lee MY, Shin YJ, Song DW, Park J, Chang BS, Lee JH. Increased Expression of Osteopontin in the Degenerating Striatum of Rats Treated with Mitochondrial Toxin 3-Nitropropionic Acid: A Light and Electron Microscopy Study. Acta Histochem Cytochem 2015; 48:135-43. [PMID: 26633905 PMCID: PMC4652028 DOI: 10.1267/ahc.15010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 09/04/2015] [Indexed: 12/16/2022] Open
Abstract
The mycotoxin 3-nitropropionic acid (3NP) is an irreversible inhibitor that induces neuronal damage by inhibiting mitochondrial complex II. Neurodegeneration induced by 3NP, which is preferentially induced in the striatum, is caused by an excess influx and accumulation of calcium in mitochondria. Osteopontin (OPN) is a glycosylated phosphoprotein and plays a role in the regulation of calcium precipitation in the injured brain. The present study was designed to examine whether induction of OPN protein is implicated in the pathogenesis of 3NP-induced striatal neurodegeneration. We observed overlapping regional expression of OPN, the neurodegeneration marker Fluoro-Jade B, and the microglial marker ionized calcium-binding adaptor molecule 1 (Iba1) in the 3NP-lesioned striatum. OPN expression was closely associated with the mitochondrial marker NADH dehydrogenase (ubiquinone) flavoprotein 2 in the damaged striatum. In addition, immunoelectron microscopy demonstrated that OPN protein was specifically localized to the inner membrane and matrix of the mitochondria in degenerating striatal neurons, and cell fragments containing OPN-labeled mitochondria were also present within activated brain macrophages. Thus, our study revealed that OPN expression is associated with mitochondrial dysfunction produced by 3NP-induced alteration of mitochondrial calcium homeostasis, suggesting that OPN is involved in the pathogenesis of striatal degeneration by 3NP administration.
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Affiliation(s)
- Hong-Lim Kim
- Department of Veterinary Anatomy, College of Veterinary Medicine, Konkuk University
- Integrative Research Support Center, College of Medicine, Catholic University
| | - Mun-Yong Lee
- Department of Anatomy, College of Medicine, Catholic University
| | - Yoo-Jin Shin
- Department of Anatomy, College of Medicine, Catholic University
| | - Doo-Won Song
- Department of Veterinary Internal Medicine, College of Veterinary Medicine, Konkuk University
| | - Jieun Park
- Integrative Research Support Center, College of Medicine, Catholic University
| | | | - Jong-Hwan Lee
- Department of Veterinary Anatomy, College of Veterinary Medicine, Konkuk University
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Jin YC, Lee H, Kim SW, Kim ID, Lee HK, Lee Y, Han PL, Lee JK. Intranasal Delivery of RGD Motif-Containing Osteopontin Icosamer Confers Neuroprotection in the Postischemic Brain via αvβ3 Integrin Binding. Mol Neurobiol 2015; 53:5652-63. [PMID: 26482372 DOI: 10.1007/s12035-015-9480-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 10/08/2015] [Indexed: 12/18/2022]
Abstract
Osteopontin (OPN) is a phosphorylated glycoprotein possessing an arginine-glycine-aspartate (RGD)-motif, which binds to several cell surface integrins and mediates a wide range of cellular processes. Inductions of OPN have been reported in the postischemic brain, and the neuroprotective effects of OPN have been demonstrated in animal models of stroke. In the present study, we showed a robust neuroprotective effect of RGD-containing icosamer OPN peptide (OPNpt20) in a rat model of focal cerebral ischemia (middle cerebral artery occlusion, MCAO). Intranasally administered OPNpt20 reduced mean infarct volume by 79.7 % compared to the treatment-naïve MCAO control animals and markedly ameliorated neurological deficits. In addition, OPNpt20 significantly suppressed the inductions of iNOS and of inflammatory markers in postischemic brains and in primary microglial cultures, demonstrating anti-inflammatory effects. Administration of a mutant peptide, in which RGD was replaced by arginine-alanine-alanine (RAA), failed to suppress infarct volumes in MCAO animals and co-administration of OPNpt20 with anti-αvβ3 integrin antibody failed to suppress iNOS induction in primary microglia culture, indicating that the RGD motif in OPNpt20 and endogenous αvβ3 integrin play critical roles. Furthermore, pull-down assay revealed a direct binding between OPNpt20 and αvβ3 integrin in primary microglia culture. Together, these results indicate that RGD-containing OPN icosamer has therapeutic potential in the postischemic brain and αvβ3 integrin-mediated anti-inflammatory effect might be an underlying mechanism.
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Affiliation(s)
- Yin-Chuan Jin
- Department of Anatomy, Inha University School of Medicine, 7-241 Shinheung-dong, Jung-Gu, Inchon, 400-712, Republic of Korea
| | - Hahnbie Lee
- Department of Anatomy, Inha University School of Medicine, 7-241 Shinheung-dong, Jung-Gu, Inchon, 400-712, Republic of Korea.,Medical Research Center, Inha University School of Medicine, Inchon, South Korea
| | - Seung-Woo Kim
- Department of Anatomy, Inha University School of Medicine, 7-241 Shinheung-dong, Jung-Gu, Inchon, 400-712, Republic of Korea.,Medical Research Center, Inha University School of Medicine, Inchon, South Korea
| | - Il-Doo Kim
- Department of Anatomy, Inha University School of Medicine, 7-241 Shinheung-dong, Jung-Gu, Inchon, 400-712, Republic of Korea.,Medical Research Center, Inha University School of Medicine, Inchon, South Korea
| | - Hye-Kyung Lee
- Department of Anatomy, Inha University School of Medicine, 7-241 Shinheung-dong, Jung-Gu, Inchon, 400-712, Republic of Korea.,Medical Research Center, Inha University School of Medicine, Inchon, South Korea
| | - Yunjin Lee
- Department of Brain and Cognitive Science, Ewha Womans University, Seoul, South Korea
| | - Pyung-Lim Han
- Department of Brain and Cognitive Science, Ewha Womans University, Seoul, South Korea
| | - Ja-Kyeong Lee
- Department of Anatomy, Inha University School of Medicine, 7-241 Shinheung-dong, Jung-Gu, Inchon, 400-712, Republic of Korea. .,Medical Research Center, Inha University School of Medicine, Inchon, South Korea.
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Riew TR, Kim HL, Shin YJ, Park JH, Pak HJ, Lee MY. Ultrastructural investigation of microcalcification and the role of oxygen-glucose deprivation in cultured rat hippocampal slices. Brain Res 2015; 1622:430-42. [PMID: 26188662 DOI: 10.1016/j.brainres.2015.06.048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 06/24/2015] [Accepted: 06/25/2015] [Indexed: 01/09/2023]
Abstract
Intracellular calcium accumulation is associated with cell death in several neuropathological disorders including brain ischemia, but the exact mechanisms of calcification need to be clarified. We used organotypic hippocampal slice culture - cultures subjected to oxygen-glucose deprivation (OGD) mimicking the in vivo situation to investigate the events underlying ectopic calcification. Alizarin red staining indicating calcium deposition was observed in the cornu ammonis (CA)1 and dentate gyrus regions in control hippocampal slices despite no specific labeling for cell death markers. Electron microscopy using the osmium/potassium dichromate method revealed scattered degenerated cells throughout the normally appearing CA1 region. They contained electron-dense precipitates within mitochondria, and electron probe microanalysis confirmed that they were calcifying mitochondria. Selective calcium deposition was noted within, but not beyond, mitochondria in these mineralized cells. They showed ultrastructural features of non-necrotic, non-apoptotic cell death and retained their compact ultrastructure, even after the majority of mitochondria were calcified. Unexpectedly, no intracellular calcification was noted in necrotic CA1 pyramidal cells after OGD, and there was no progression of calcification in OGD-lesioned slices. In addition, mineralized cells in both control and OGD-lesioned slices were closely associated with or completely engulfed by astrocytes but not microglia. These astrocytes were laden with heterogeneous cytoplasmic inclusions that appeared to be related with their phagocytic activity. These data demonstrate that microcalcification specifically associated with mitochondria might lead to a novel type of cell death and suggest that astrocytes may be involved in the phagocytosis of these mineralized cells and possibly in the regulation of ectopic calcification.
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Affiliation(s)
- Tae-Ryong Riew
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 137-701 Seoul, Korea
| | - Hong Lim Kim
- Integrative Research Support Center, Laboratory of Electron Microscope, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Yoo-Jin Shin
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 137-701 Seoul, Korea
| | - Joo-Hee Park
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 137-701 Seoul, Korea
| | - Ha-Jin Pak
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 137-701 Seoul, Korea
| | - Mun-Yong Lee
- Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 137-701 Seoul, Korea.
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Nemeth CL, Neigh GN. Microemboli alter the acute stress response and cause prolonged expression of MCP-1 in the hippocampus. Psychoneuroendocrinology 2015; 54:71-7. [PMID: 25697594 DOI: 10.1016/j.psyneuen.2015.01.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 01/05/2015] [Accepted: 01/27/2015] [Indexed: 10/24/2022]
Abstract
Microvascular ischemia is linked to cardiovascular disease pathology, as well as alterations in mood and cognition. Ischemia activates the hypothalamic-pituitary-adrenal (HPA) axis and through chronic activation, alters HPA axis function. Dysregulation of the HPA axis can lead to the chronic release of glucocorticoids, a hyper-inflammatory cerebral response, cell damage, and changes in behavior. Although the interactions between injury and HPA axis activity have been established in global ischemia, HPA-related repercussions of diffuse ischemic damage and subsequent inflammation have not been assessed. The current study used a rat model of microsphere embolism (ME) ischemia to test the hypothesis that microvascular ischemia would lead to long term alterations in HPA axis function and inflammatory activity. Furthermore, given the pro-inflammatory nature of chronic stress, we assessed the implications of chronic stress for gene expression of inflammatory factors and key components of the glucocorticoid receptor response, following microvascular ischemia. Results indicated that ME altered the response to an acute stress fourteen days following ME injury and increased hippocampal expression of monocyte chemoattractant protein 1 (Mcp-1) as long as 4 weeks following ME injury, without concomitant effects on gene expression of the glucocorticoid receptor or its co-chaperones. Furthermore, no exacerbative effects of chronic stress exposure were observed following ME injury beyond the effects of ME injury alone. Together, these results indicate that ME injury is sufficient to alter both HPA axis activity and cerebral inflammation for a prolonged period of time following injury.
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Affiliation(s)
- Christina L Nemeth
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, United States; Department of Physiology, Emory University, Atlanta, GA, United States
| | - Gretchen N Neigh
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, United States; Department of Physiology, Emory University, Atlanta, GA, United States.
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Cuadrado E, Jansen MH, Anink J, De Filippis L, Vescovi AL, Watts C, Aronica E, Hol EM, Kuijpers TW. Chronic exposure of astrocytes to interferon-α reveals molecular changes related to Aicardi–Goutières syndrome. Brain 2013; 136:245-58. [DOI: 10.1093/brain/aws321] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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Peng H, Ouyang JM, Yao XQ, Yang RE. Interaction between submicron COD crystals and renal epithelial cells. Int J Nanomedicine 2012; 7:4727-37. [PMID: 22973095 PMCID: PMC3433325 DOI: 10.2147/ijn.s33848] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Objectives This study aims to investigate the adhesion characteristics between submicron calcium oxalate dihydrate (COD) with a size of 150 ± 50 nm and African green monkey kidney epithelial cells (Vero cells) before and after damage, and to discuss the mechanism of kidney stone formation. Methods Vero cells were oxidatively injured by hydrogen peroxide to establish a model of injured cells. Scanning electron microscopy was used to observe Vero–COD adhesion. Inductively coupled plasma emission spectrometry was used to quantitatively measure the amount of adhered COD microcrystals. Nanoparticle size analyzer and laser scanning confocal microscopy were performed to measure the change in the zeta potential on the Vero cell surface and the change in osteopontin expression during the adhesion process, respectively. The level of cell injury was evaluated by measuring the changes in malonaldehyde content, and cell viability during the adhesion process. Results The adhesion capacity of Vero cells in the injury group to COD microcrystals was obviously stronger than that of Vero cells in the control group. After adhesion to COD, cell viability dropped, both malonaldehyde content and cell surface zeta potential increased, and the fluorescence intensity of osteopontin decreased because the osteopontin molecules were successfully covered by COD. Submicron COD further damaged the cells during the adhesion process, especially for Vero cells in the control group, leading to an elevated amount of attached microcrystals. Conclusion Submicron COD can further damage injured Vero cells during the adhesion process. The amount of attached microcrystals is proportional to the degree of cell damage. The increased amount of microcrystals that adhered to the injured epithelial cells plays an important role in the formation of early-stage kidney stones.
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Affiliation(s)
- Hua Peng
- Department of Chemistry, Jinan University, Guangzhou, China
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Park JM, Shin YJ, Kim HL, Cho JM, Lee MY. Sustained expression of osteopontin is closely associated with calcium deposits in the rat hippocampus after transient forebrain ischemia. J Histochem Cytochem 2012; 60:550-9. [PMID: 22496158 DOI: 10.1369/0022155412441707] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present study was designed to evaluate the extent and topography of osteopontin (OPN) protein expression in the rat hippocampus 4 to 12 weeks following transient forebrain ischemia, and to compare OPN expression patterns with those of calcium deposits and astroglial and microglial reactions. Two patterns of OPN staining were recognized by light microscopy: 1) a diffuse pattern of tiny granular deposits throughout the CA1 region at 4 weeks after ischemia and 2) non-diffuse ovoid to round deposits, which formed conglomerates in the CA1 pyramidal cell layer over the chronic interval of 8 to 12 weeks. Immunogold-silver electron microscopy and electron probe microanalysis demonstrated that OPN deposits were indeed diverse types of calcium deposits, which were clearly delineated by profuse silver grains indicative of OPN expression. Intracellular OPN deposits were frequently observed within reactive astrocytes and neurons 4 weeks after ischemia but rarely at later times. By contrast, extracellular OPN deposits progressively increased in size and appeared to be gradually phagocytized by microglia or brain macrophages and some astrocytes over 8 to 12 weeks. These data indicate an interaction between OPN and calcium in the hippocampus in the chronic period after ischemia, suggesting that OPN binding to calcium deposits may be involved in scavenging mechanisms.
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Affiliation(s)
- Jang-Mi Park
- Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul, Korea
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