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Xi XR, Zhang ZQ, Li YL, Liu Z, Ma DY, Gao Z, Zhang S. Hypothermia promotes tunneling nanotube formation and the transfer of astrocytic mitochondria into oxygen-glucose deprivation/reoxygenation-injured neurons. Brain Res 2024; 1831:148826. [PMID: 38403036 DOI: 10.1016/j.brainres.2024.148826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/20/2024] [Accepted: 02/22/2024] [Indexed: 02/27/2024]
Abstract
Mitochondrial transfer occurs between cells, and it is important for damaged cells to receive healthy mitochondria to maintain their normal function and protect against cell death. Accumulating evidence suggests that the functional mitochondria of astrocytes are released and transferred to oxygen-glucose deprivation/reoxygenation (OGD/R)-injured neurons. Mild hypothermia (33 °C) is capable of promoting this process, which partially restores the function of damaged neurons. However, the pathways and mechanisms by which mild hypothermia facilitates mitochondrial transfer remain unclear. We are committed to studying the role of mild hypothermia in neuroprotection to provide reliable evidences and insights for the clinical application of mild hypothermia in brain protection. Tunneling nanotubes (TNTs) are considered to be one of the routes through which mitochondria are transferred between cells. In this study, an OGD/R-injured neuronal model was successfully established, and TNTs, mitochondria, neurons and astrocytes were double labeled using immunofluorescent probes. Our results showed that TNTs were present and involved in the transfer of mitochondria between cells in the mixed-culture system of neurons and astrocytes. When neurons were subjected to OGD/R exposure, TNT formation and mitochondrial transportation from astrocytes to injured neurons were facilitated. Further analysis revealed that mild hypothermia increased the quantity of astrocytic mitochondria transferred into damaged neurons through TNTs, raised the mitochondrial membrane potential (MMP), and decreased the neuronal damage and death during OGD/R. Altogether, our data indicate that TNTs play an important role in the endogenous neuroprotection of astrocytic mitochondrial transfer. Furthermore, mild hypothermia enhances astrocytic mitochondrial transfer into OGD/R-injured neurons via TNTs, thereby promoting neuroprotection and neuronal recovery.
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Affiliation(s)
- Xiao-Rui Xi
- Department of Anesthesiology, Second Hospital of Hebei Medical University, Shijiazhuang, 050000 Hebei, China
| | - Zhi-Qiang Zhang
- Department of Anesthesiology, Second Hospital of Hebei Medical University, Shijiazhuang, 050000 Hebei, China
| | - Yan-Li Li
- Department of Anesthesiology, Second Hospital of Hebei Medical University, Shijiazhuang, 050000 Hebei, China
| | - Zheng Liu
- Department of Anesthesiology, Second Hospital of Hebei Medical University, Shijiazhuang, 050000 Hebei, China
| | - Dong-Yang Ma
- Department of Anesthesiology, Second Hospital of Hebei Medical University, Shijiazhuang, 050000 Hebei, China
| | - Zan Gao
- Department of Anesthesiology, Second Hospital of Hebei Medical University, Shijiazhuang, 050000 Hebei, China
| | - Shan Zhang
- Department of Anesthesiology, Second Hospital of Hebei Medical University, Shijiazhuang, 050000 Hebei, China.
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Narayanamurthy R, Armstrong EA, Yang JLJ, Yager JY, Unsworth LD. Administration of selective brain hypothermia using a simple cooling device in neonatal rats. J Neurosci Methods 2023; 390:109838. [PMID: 36933705 DOI: 10.1016/j.jneumeth.2023.109838] [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: 12/29/2021] [Revised: 03/03/2023] [Accepted: 03/14/2023] [Indexed: 03/18/2023]
Abstract
BACKGROUND The interruption of oxygen and blood supply to the newborn brain around the time of birth is a risk factor for hypoxic-ischemic encephalopathy and may lead to infant mortality or lifelong neurological impairments. Currently, therapeutic hypothermia, the cooling of the infant's head or entire body, is the only treatment to curb the extent of brain damage. NEW METHOD In this study, we designed a focal brain cooling device that circulates cooled water at a steady state temperature of 19 ± 1 °C through a coil of tubing fitted onto the neonatal rat's head. We tested its ability to selectively decrease brain temperature and offer neuroprotection in a neonatal rat model of hypoxic-ischemic brain injury. RESULTS Our method cooled the brain to 30-33 °C in conscious pups, while keeping the core body temperature approximately 3.2 °C warmer. Furthermore, the application of the cooling device to the neonatal rat model demonstrated a reduction in brain volume loss compared to pups maintained at normothermia and achieved a level of brain tissue protection the same as that of whole-body cooling. COMPARISON WITH EXISTING METHODS Prevailing methods of selective brain hypothermia are designed for adult animal models rather than for immature animals such as the rat as a conventional model of developmental brain pathology. Contrary to existing methods, our method of cooling does not require surgical manipulation or anaesthesia. CONCLUSION Our simple, economical, and effective method of selective brain cooling is a useful tool for rodent studies in neonatal brain injury and adaptive therapeutic interventions.
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Affiliation(s)
- Rukhmani Narayanamurthy
- Department of Pediatrics, Division of Pediatric Neurosciences, University of Alberta, 11405 87 Avenue, Edmonton, Alberta T6G 1C9, Canada
| | - Edward A Armstrong
- Department of Pediatrics, Division of Pediatric Neurosciences, University of Alberta, 11405 87 Avenue, Edmonton, Alberta T6G 1C9, Canada
| | - Jung-Lynn Jonathan Yang
- Department of Chemical and Materials Engineering, University of Alberta, 11487 89 Avenue, Edmonton, Alberta T6G 2M7, Canada
| | - Jerome Y Yager
- Department of Pediatrics, Division of Pediatric Neurosciences, University of Alberta, 11405 87 Avenue, Edmonton, Alberta T6G 1C9, Canada
| | - Larry D Unsworth
- Department of Chemical and Materials Engineering, University of Alberta, 11487 89 Avenue, Edmonton, Alberta T6G 2M7, Canada.
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Li M, Yu J, Deng H, Xie S, Li Q, Zhao Y, Yin S, Ji YF. Upregulation of glutamate transporter 1 by mTOR/Akt pathway in astrocyte culture during oxygen-glucose deprivation and reoxygenation. Exp Brain Res 2023; 241:201-209. [PMID: 36436003 DOI: 10.1007/s00221-022-06514-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 11/16/2022] [Indexed: 11/28/2022]
Abstract
Astrocyte-specific glutamate transporter subtype 1 (GLT-1) plays an important role in influencing glutamate excitatory toxicity and preventing the death of excitatory toxic neurons. Although the mammalian target of rapamycin (mTOR)/protein kinase B(Akt)/nuclear factor kappa B signaling cascade is involved in the upregulation of astrocytic GLT-1 in oxygen-glucose deprivation (OGD), it is unclear whether the mTOR/Akt pathway is involved in astrocytic GLT-1 upregulation in OGD and reoxygenation (OGD/R). In this study, we found that the treatment of cultured astrocytes with rapamycin and triciribine led to the decreased astrocytes' protrusions, smaller nuclei, and an increased apoptotic rate. The inhibitors of mTOR complex 1 significantly increased the expression levels of phosphorylated Akt-Ser473 (p-Akt), phosphorylated Akt-Thr308(p-Akt), and GLT-1, while Akt-specific inhibitors blocked GLT-1 expression, suggesting that the mTOR/Akt pathway is involved in GLT-1 upregulation. We further demonstrated that astrocytes under OGD/R adapted to environmental changes through the mTOR/Akt pathway, mainly by altering cell morphology and apoptosis and upregulating the expression levels of p-Akt and GLT-1. Our results suggested that astrocytes may adapt to short-term ischemic-reperfusion injury by regulating cell morphology, apoptosis and GLT-1 upregulation.
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Affiliation(s)
- Mi Li
- Department of Neurology, Second Clinical College, North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China
- Department of Neurology, Yilong County People's Hospital, Nanchong, Sichuan, People's Republic of China
| | - Jingmei Yu
- Department of Neurology, Second Clinical College, North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China
| | - Huan Deng
- Department of Neurology, Second Clinical College, North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China
| | - Shansha Xie
- Department of Neurology, Second Clinical College, North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China
| | - Qiuling Li
- Department of Neurology, Second Clinical College, North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China
| | - Yuping Zhao
- Department of Neurology, Second Clinical College, North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China
| | - Shubin Yin
- Department of Neurology, Second Clinical College, North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China
| | - Yi-Fei Ji
- Department of Neurology, Second Clinical College, North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China.
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Yan C, Mao J, Yao C, Liu Y, Yan H, Jin W. Neuroprotective effects of mild hypothermia against traumatic brain injury by the involvement of the Nrf2/ARE pathway. Brain Behav 2022; 12:e2686. [PMID: 35803901 PMCID: PMC9392531 DOI: 10.1002/brb3.2686] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 06/01/2022] [Accepted: 06/14/2022] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Traumatic brain injury (TBI) is the leading cause of death and disability worldwide. Mild hypothermia (32-35°C) has been found to show neuroprotective effects against TBI. However, the specific mechanism is still elusive. In the current study, we explored the relationship between oxidative damage after TBI and treatment with mild hypothermia as well as the underlying molecular mechanisms. METHODS We used the closed cortex injury model to perform the brain injury and a temperature monitoring and control system to regulate the body temperature of mice after injury. Adult male C57BL/6 mice were adopted in this study and divided into four experimental groups. Tissue samples were harvested 24 h after injury. RESULTS First, our results showed that treatment with mild hypothermia significantly improved neurobehavioral dysfunction and alleviated brain edema after TBI. Moreover, treatment with mild hypothermia enhanced the activity of the antioxidant enzymes superoxide dismutase and glutathione peroxidase and reduced the accumulation of lipid peroxidation malondialdehyde. Importantly, the expression and activation of the nuclear factor erythroid 2-related factor 2-antioxidant response element (Nrf2-ARE) pathway were upregulated by mild hypothermia after TBI. Finally, treatment with hypothermia significantly decreased the cell apoptosis induced by TBI. CONCLUSION Our results showed that the protective effects of mild hypothermia after TBI may be achieved by the upregulation of the Nrf2-ARE pathway and revealed Nrf2 as a potentially important target to improve the prognosis of TBI.
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Affiliation(s)
- Chaolong Yan
- Department of Neurosurgery, Nanjing Drum Tower Hospital, Clinical College of Nanjing Medical University, Nanjing, China.,Department of Neurosurgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China.,Department of Neurosurgery, Zhongshan Hospital, The Affiliated Hospital of Fudan University, Shanghai, China
| | - Jiannan Mao
- Department of Neurosurgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Chenbei Yao
- Department of Neurosurgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Yang Liu
- Department of Neurosurgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Huiying Yan
- Department of Neurosurgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Wei Jin
- Department of Neurosurgery, Nanjing Drum Tower Hospital, Clinical College of Nanjing Medical University, Nanjing, China.,Department of Neurosurgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
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Jia Y, Yang J, Lu T, Pu X, Chen Q, Ji L, Luo C. Repair of spinal cord injury in rats via exosomes from bone mesenchymal stem cells requires sonic hedgehog. Regen Ther 2021; 18:309-315. [PMID: 34522723 PMCID: PMC8416644 DOI: 10.1016/j.reth.2021.08.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/24/2021] [Accepted: 08/16/2021] [Indexed: 12/18/2022] Open
Abstract
Objective The loss of neural ability leading to subsequent diminishing of motor function and the impairment below the location of the injury is a result of the SCI (Spinal Cord Injury). Among the many therapeutic agents for SCI, the exosomes considered as extracellular vesicles seem to be the most promising. Sonic Hedgehog (Shh) is an exosome-carrying protein. This Study's purpose was to identify whether Shh is required for exosomes from BMSCs (mesenchymal stem cells of the bone) and plays a protective effect on SCI. Methods Spinal cord injection with shRNA Shh-adeno associated virus (sh-Shh-AAV) were used to silence Shh. Exosomes were extracted from BMSCs. Rats that had suffered SCI were given intravenous injections of exosomes through the veins of the tail. Immunohistochemistry was used to identify the expression of Shh glycoprotein molecule as well as the expression of Gli-1 (glioma-associated oncogene homolog 1) in the rat spinal cord tissues. Western blot was performed to measure the levels of growth associated protein-43 (GAP-43). The BBB (Basso Beattie Bresnahan) score was used to assess the motor functions of the hind legs. In the same manner, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling or TUNEL and Nissl Staining was deployed to assess the level of regeneration of neurons and assess the level of histopathological damage in the tissues of the Spinal Cord. Results In the case of the rats with SCI, the levels of display of Gli-1 and Shh showed dramatic improvement after the BMSCs exosome injections. In comparison to rats with SCI, the subjects of BMSCs exosomes group showed an improvement in their SCI, including a higher BBB score and Nissl body count, increasing GAP-43 expression, along with a much-decreased number of cells that suffered apoptosis. While the exosome effect on Spinal Cord Injury was completely ineffective in rats that had Shh silencing. Conclusions Exosomes secreted from BMSCs showed great effectiveness in the SCI healing with a vital involvement of Shh in this repair.
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Affiliation(s)
- Yijia Jia
- Department of Spine Surgery, Guizhou Province Osteological Hospital, Guiyang, 550002, China
| | - Jianwen Yang
- Department of Spine Surgery, Guizhou Province Osteological Hospital, Guiyang, 550002, China
| | - Tingsheng Lu
- Department of Spine Surgery, Guizhou Province Osteological Hospital, Guiyang, 550002, China
| | - Xingwei Pu
- Department of Spine Surgery, Guizhou Province Osteological Hospital, Guiyang, 550002, China
| | - Qiling Chen
- Department of Spine Surgery, Guizhou Province Osteological Hospital, Guiyang, 550002, China
| | - Linsong Ji
- Department of Spine Surgery, Guizhou Province Osteological Hospital, Guiyang, 550002, China
| | - Chunshan Luo
- Department of Spine Surgery, Guizhou Province Osteological Hospital, Guiyang, 550002, China
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Li X, Li Y, Zhang Z, Bian Q, Gao Z, Zhang S. Mild hypothermia facilitates mitochondrial transfer from astrocytes to injured neurons during oxygen-glucose deprivation/reoxygenation. Neurosci Lett 2021; 756:135940. [PMID: 33971244 DOI: 10.1016/j.neulet.2021.135940] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 04/21/2021] [Accepted: 04/29/2021] [Indexed: 01/16/2023]
Abstract
Mitochondrial dysfunction is now considered an important sign of neuronal death during cerebral ischemia/reperfusion (I/R) injury. Studies have shown that the transfer of mitochondria from astrocytes to injured neurons contributes to endogenous neuroprotection after stroke. Basic and clinical studies have shown that mild hypothermia exerts a clear protective effect on neurons after cerebral ischemic injury, but the role of mild hypothermia in this endogenous neuroprotective mechanism remains unclear. Here, we established a neuronal cell oxygen-glucose deprivation (OGD)/reoxygenation (OGD/R)-induced injury model and explored the effect of mild hypothermia on the transfer of mitochondria from astrocytes to injured neurons. Astrocytes in the hypothermia group (33 °C) released more functional mitochondria into the extracellular medium than those in the normal temperature group (37 °C). Compared with cells in the normal temperature group, OGD-injured neuronal cells in the mild hypothermia group exhibited an increased intracellular ATP content, mitochondrial membrane potential (MMP) and cellular viability and a decreased death rate after the addition of astrocyte-derived conditioned medium. Based on the results of this study, mild hypothermia promotes endogenous neuroprotective effects through a mechanism related to functional mitochondria released from astrocytes into the extracellular space and transferred into injured neurons.
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Affiliation(s)
- Xiaowei Li
- Department of Anesthesiology, Second Hospital of Hebei Medical University, Shijiazhuang, 050000, Hebei, China
| | - Yanli Li
- Department of Anesthesiology, Second Hospital of Hebei Medical University, Shijiazhuang, 050000, Hebei, China
| | - Zhiqiang Zhang
- Department of Anesthesiology, Second Hospital of Hebei Medical University, Shijiazhuang, 050000, Hebei, China
| | - Qinghu Bian
- Department of Anesthesiology, Second Hospital of Hebei Medical University, Shijiazhuang, 050000, Hebei, China
| | - Zan Gao
- Department of Anesthesiology, Second Hospital of Hebei Medical University, Shijiazhuang, 050000, Hebei, China
| | - Shan Zhang
- Department of Anesthesiology, Second Hospital of Hebei Medical University, Shijiazhuang, 050000, Hebei, China.
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