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Li J, Xue C, Yang H, Zhang J, Li G, Li J, Kuang F, Chen J, Zhang S, Gao F, Kou Z, Zhang X, Dong L. Simulated weightlessness induces hippocampal insulin resistance and cognitive impairment. Life Sci 2023; 333:122112. [PMID: 37758017 DOI: 10.1016/j.lfs.2023.122112] [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: 03/14/2023] [Revised: 09/05/2023] [Accepted: 09/18/2023] [Indexed: 10/03/2023]
Abstract
Growing evidence highlights the potential consequences of long-term spaceflight, including gray matter volume reduction and cognitive dysfunction with subclinical manifestations of diabetes mellitus among astronauts, but the underlying mechanisms remain unknown. In this study, we found that long-term simulated weightlessness induced hippocampal insulin resistance and subsequent neuronal damage and cognitive impairment in rats. Rats subjected to 4-week tail suspension exhibited peripheral insulin resistance, evidenced by increased fasting blood glucose and abnormal glucose tolerance and insulin tolerance, alongside reduced spontaneous activity and impaired recognition memory. In addition, 4 weeks of simulated weightlessness induced neuronal apoptosis and degeneration in the hippocampus, as evidenced by increased TUNEL and Fluoro-Jade B staining-positive neurons. Mechanistically, insulin-stimulated hippocampal Akt phosphorylation was decreased, while PTEN, the negative regulator of insulin signaling, was increased in the hippocampus in tail-suspended rats. Interestingly, treatment with berberine, an insulin sensitizer, partly reversed the above-mentioned effects induced by simulated weightlessness. These data suggest that long-term simulated weightlessness induces cognitive impairment as well as neuronal apoptosis and neural degeneration, partially through hippocampal insulin resistance via PTEN up-regulation. Berberine treatment attenuates hippocampal insulin resistance and improves cognitive function.
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Affiliation(s)
- Jiahui Li
- Key Laboratory of Aerospace Medicine of the Ministry of Education, School of Aerospace Medicine, Air Force Medical University, Xi'an, China; Department of Psychology, Air Force Hospital, Western Theater Command, Chengdu, China
| | - Caiyan Xue
- Key Laboratory of Aerospace Medicine of the Ministry of Education, School of Aerospace Medicine, Air Force Medical University, Xi'an, China
| | - Hongyan Yang
- Key Laboratory of Aerospace Medicine of the Ministry of Education, School of Aerospace Medicine, Air Force Medical University, Xi'an, China
| | - Jiaxin Zhang
- Key Laboratory of Aerospace Medicine of the Ministry of Education, School of Aerospace Medicine, Air Force Medical University, Xi'an, China
| | - Guohua Li
- Key Laboratory of Aerospace Medicine of the Ministry of Education, School of Aerospace Medicine, Air Force Medical University, Xi'an, China
| | - Jijun Li
- Key Laboratory of Aerospace Medicine of the Ministry of Education, School of Aerospace Medicine, Air Force Medical University, Xi'an, China
| | - Fang Kuang
- Department of Neurobiology, Air Force Medical University, Xi'an, China
| | - Jing Chen
- Department of Anatomy, Histology and Embryology & K. K. Leung Brain Research Centre, Air Force Medical University, Xi'an, China
| | - Shu Zhang
- Key Laboratory of Aerospace Medicine of the Ministry of Education, School of Aerospace Medicine, Air Force Medical University, Xi'an, China
| | - Feng Gao
- Key Laboratory of Aerospace Medicine of the Ministry of Education, School of Aerospace Medicine, Air Force Medical University, Xi'an, China
| | - Zhenzhen Kou
- Department of Anatomy, Histology and Embryology & K. K. Leung Brain Research Centre, Air Force Medical University, Xi'an, China.
| | - Xing Zhang
- Key Laboratory of Aerospace Medicine of the Ministry of Education, School of Aerospace Medicine, Air Force Medical University, Xi'an, China.
| | - Ling Dong
- Key Laboratory of Aerospace Medicine of the Ministry of Education, School of Aerospace Medicine, Air Force Medical University, Xi'an, China.
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Graves LY, Keane KF, Taylor JY, Wang TF, Saligan L, Bogie KM. Subacute and Chronic Spinal Cord Injury: A Scoping Review of Epigenetics and Secondary Health Conditions. Epigenet Insights 2023; 16:25168657231205679. [PMID: 37900668 PMCID: PMC10612389 DOI: 10.1177/25168657231205679] [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: 02/23/2023] [Accepted: 09/11/2023] [Indexed: 10/31/2023] Open
Abstract
Background Epigenetics studies the impact of environmental and behavioral factors on stable phenotypic changes; however, the state of the science examining epigenomic mechanisms of regulation related to secondary health conditions (SHCs) and neuroepigenetics in chronic spinal cord injury (SCI) remain markedly underdeveloped. Objective This scoping review seeks to understand the state of the science in epigenetics and secondary complications following SCI. Methods A literature search was conducted, yielding 277 articles. The inclusion criteria were articles (1) investigating SCI and (2) examining epigenetic regulation as part of the study methodology. A total of 23 articles were selected for final inclusion. Results Of the 23 articles 52% focused on histone modification, while 26% focused on DNA methylation. One study had a human sample, while the majority sampled rats and mice. Primarily, studies examined regeneration, with only one study looking at clinically relevant SHC, such as neuropathic pain. Discussion The findings of this scoping review offer exciting insights into epigenetic and neuroepigenetic application in SCI research. Several key genes, proteins, and pathways emerged across studies, suggesting the critical role of epigenetic regulation in biological processes. This review reinforced the dearth of studies that leverage epigenetic methods to identify prognostic biomarkers in SHCs. Preclinical models of SCI were genotypically and phenotypically similar, which is not reflective of the heterogeneity found in the clinical population of persons with SCI. There is a need to develop better preclinical models and more studies that examine the role of genomics and epigenomics in understanding the diverse health outcomes associated with traumatic SCI.
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Affiliation(s)
- Letitia Y Graves
- School of Nursing, University of Texas Medical Branch, Galveston, TX, USA
- Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH, USA
| | - Kayla F Keane
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Jacquelyn Y Taylor
- Columbia School of Nursing and Center for Research on People of Color, New York, NY, USA
| | - Tzu-fang Wang
- National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Leorey Saligan
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Kath M Bogie
- Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH, USA
- Case Western Reserve University, Cleveland, OH, USA
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Stewart AN, Kumari R, Bailey WM, Glaser EP, Bosse-Joseph CC, Park KA, Hammers GV, Wireman OH, Gensel JC. PTEN knockout using retrogradely transported AAVs transiently restores locomotor abilities in both acute and chronic spinal cord injury. Exp Neurol 2023; 368:114502. [PMID: 37558155 PMCID: PMC10498341 DOI: 10.1016/j.expneurol.2023.114502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 07/07/2023] [Accepted: 08/07/2023] [Indexed: 08/11/2023]
Abstract
Restoring function in chronic stages of spinal cord injury (SCI) has often been met with failure or reduced efficacy when regenerative strategies are delayed past the acute or sub-acute stages of injury. Restoring function in the chronically injured spinal cord remains a critical challenge. We found that a single injection of retrogradely transported adeno-associated viruses (AAVrg) to knockout the phosphatase and tensin homolog protein (PTEN) in chronic SCI can effectively target both damaged and spared axons and transiently restore locomotor functions in near-complete injury models. AAVrg's were injected to deliver cre recombinase and/or a red fluorescent protein (RFP) under the human Synapsin 1 promoter (hSyn1) into the spinal cords of C57BL/6 PTENFloxΔ/Δ mice to knockout PTEN (PTEN-KO) in a severe thoracic SCI crush model at both acute and chronic time points. PTEN-KO improved locomotor abilities in both acute and chronic SCI conditions over a 9-week period. Regardless of whether treatment was initiated at the time of injury (acute), or three months after SCI (chronic), mice with limited hindlimb joint movement gained hindlimb weight support after treatment. Interestingly, functional improvements were not sustained beyond 9 weeks coincident with a loss of RFP reporter-gene expression and a near-complete loss of treatment-associated functional recovery by 6 months post-treatment. Treatment effects were also specific to severely injured mice; animals with weight support at the time of treatment lost function over a 6-month period. Retrograde tracing with Fluorogold revealed viable neurons throughout the motor cortex despite a loss of RFP expression at 9 weeks post-PTEN-KO. However, few Fluorogold labeled neurons were detected within the motor cortex at 6 months post-treatment. BDA labeling from the motor cortex revealed a dense corticospinal tract (CST) bundle in all groups except chronically treated PTEN-KO mice, indicating a potential long-term toxic effect of PTEN-KO to neurons in the motor cortex which was corroborated by a loss of β-tubulin III labeling above the lesion within spinal cords after PTEN-KO. PTEN-KO mice had significantly more β-tubulin III labeled axons within the lesion when treatment was delivered acutely, but not chronically post-SCI. In conclusion, we have found that using AAVrg's to knockout PTEN is an effective manipulation capable of restoring motor functions in chronic SCI and can enhance axon growth of currently unidentified axon populations when delivered acutely after injury. However, the long-term consequences of PTEN-KO on neuronal health and viability should be further explored.
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Affiliation(s)
- Andrew N Stewart
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA.
| | - Reena Kumari
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - William M Bailey
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - Ethan P Glaser
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - Christopher C Bosse-Joseph
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - Kennedy A Park
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - Gabrielle V Hammers
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - Olivia H Wireman
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - John C Gensel
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA; Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA; College of Medicine, University of Kentucky, Lexington, KY 40536, USA.
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Stewart AN, Kumari R, Bailey WM, Glaser EP, Hammers GV, Wireman OH, Gensel JC. PTEN knockout using retrogradely transported AAVs restores locomotor abilities in both acute and chronic spinal cord injury. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.17.537179. [PMID: 37131840 PMCID: PMC10153160 DOI: 10.1101/2023.04.17.537179] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Restoring function in chronic stages of spinal cord injury (SCI) has often been met with failure or reduced efficacy when regenerative strategies are delayed past the acute or sub-acute stages of injury. Restoring function in the chronically injured spinal cord remains a critical challenge. We found that a single injection of retrogradely transported adeno-associated viruses (AAVrg) to knockout the phosphatase and tensin homolog protein (PTEN) in chronic SCI can effectively target both damaged and spared axons and restore locomotor functions in near-complete injury models. AAVrg's were injected to deliver cre recombinase and/or a red fluorescent protein (RFP) under the human Synapsin 1 promoter (hSyn1) into the spinal cords of C57BL/6 PTEN FloxΔ / Δ mice to knockout PTEN (PTEN-KO) in a severe thoracic SCI crush model at both acute and chronic time points. PTEN-KO improved locomotor abilities in both acute and chronic SCI conditions over a 9-week period. Regardless of whether treatment was initiated at the time of injury (acute), or three months after SCI (chronic), mice with limited hindlimb joint movement gained hindlimb weight support after treatment. Interestingly, functional improvements were not sustained beyond 9 weeks coincident with a loss of RFP reporter-gene expression and a near-complete loss of treatment-associated functional recovery by 6 months post-treatment. Treatment effects were also specific to severely injured mice; animals with weight support at the time of treatment lost function over a 6-month period. Retrograde tracing with Fluorogold revealed viable neurons throughout the motor cortex despite a loss of RFP expression at 9 weeks post-PTEN-KO. However, few Fluorogold labeled neurons were detected within the motor cortex at 6 months post-treatment. BDA labeling from the motor cortex revealed a dense corticospinal tract (CST) bundle in all groups except chronically treated PTEN-KO mice indicating a potential long-term toxic effect of PTEN-KO to neurons in the motor cortex. PTEN-KO mice had significantly more β - tubulin III labeled axons within the lesion when treatment was delivered acutely, but not chronically post-SCI. In conclusion, we have found that using AAVrg's to knockout PTEN is an effective manipulation capable of restoring motor functions in chronic SCI and can enhance axon growth of currently unidentified axon populations when delivered acutely after injury. However, the long-term consequences of PTEN-KO may exert neurotoxic effects.
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Affiliation(s)
- Andrew N. Stewart
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, USA
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536, USA
| | - Reena Kumari
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, USA
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536, USA
| | - William M. Bailey
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, USA
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536, USA
| | - Ethan P. Glaser
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, USA
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536, USA
| | - Gabrielle V. Hammers
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, USA
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536, USA
| | - Olivia H. Wireman
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, USA
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536, USA
| | - John C. Gensel
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536, USA
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536, USA
- College of Medicine, University of Kentucky, Lexington, Kentucky 40536, USA
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