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Ma F, Akolkar H, Xu J, Liu Y, Popova D, Xie J, Youssef MM, Benosman R, Hart RP, Herrup K. The Amyloid Precursor Protein Modulates the Position and Length of the Axon Initial Segment. J Neurosci 2023; 43:1830-1844. [PMID: 36717226 PMCID: PMC10010458 DOI: 10.1523/jneurosci.0172-22.2023] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 01/23/2023] [Accepted: 01/24/2023] [Indexed: 01/31/2023] Open
Abstract
The amyloid precursor protein (APP) is linked to the genetics and pathogenesis of Alzheimer's disease (AD). It is the parent protein of the β-amyloid (Aβ) peptide, the main constituent of the amyloid plaques found in an AD brain. The pathways from APP to Aβ are intensively studied, yet the normal functions of APP itself have generated less interest. We report here that glutamate stimulation of neuronal activity leads to a rapid increase in App gene expression. In mouse and human neurons, elevated APP protein changes the structure of the axon initial segment (AIS) where action potentials are initiated. The AIS is shortened in length and shifts away from the cell body. The GCaMP8f Ca2+ reporter confirms the predicted decrease in neuronal activity. NMDA antagonists or knockdown of App block the glutamate effects. The actions of APP on the AIS are cell-autonomous; exogenous Aβ, either fibrillar or oligomeric, has no effect. In culture, APPSwe (a familial AD mutation) induces larger AIS changes than wild type APP. Ankyrin G and βIV-spectrin, scaffolding proteins of the AIS, both physically associate with APP, more so in AD brains. Finally, in humans with sporadic AD or in the R1.40 AD mouse model, both females and males, neurons have elevated levels of APP protein that invade the AIS. In vivo as in vitro, this increased APP is associated with a significant shortening of the AIS. The findings outline a new role for the APP and encourage a reconsideration of its relationship to AD.SIGNIFICANCE STATEMENT While the amyloid precursor protein (APP) has long been associated with Alzheimer's disease (AD), the normal functions of the full-length Type I membrane protein have been largely unexplored. We report here that the levels of APP protein increase with neuronal activity. In vivo and in vitro, modest amounts of excess APP alter the properties of the axon initial segment. The β-amyloid peptide derived from APP is without effect. Consistent with the observed changes in the axon initial segment which would be expected to decrease action potential firing, we show that APP expression depresses neuronal activity. In mouse AD models and human sporadic AD, APP physically associates with the scaffolding proteins of the axon initial segment, suggesting a relationship with AD dementia.
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Affiliation(s)
- Fulin Ma
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Himanshu Akolkar
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Jianquan Xu
- Departments of Medicine and Bioengineering, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Yang Liu
- Departments of Medicine and Bioengineering, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Dina Popova
- Human Genetics Institute, Rutgers University, Piscataway, NJ 08854
| | - Jiaan Xie
- Departments of Medicine and Bioengineering, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Mark M Youssef
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854
| | - Ryad Benosman
- Robotics Institute, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Ronald P Hart
- Human Genetics Institute, Rutgers University, Piscataway, NJ 08854
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854
| | - Karl Herrup
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Departments of Medicine and Bioengineering, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
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Mektrirat R, Rueangsri T, Keeratichandacha W, Soonsawat S, Boonyapakorn C, Pongkan W. Polyunsaturated Fatty Acid EAB-277 ® Supplementation Improved Heart Rate Variability and Clinical Signs in Tracheal Collapse Dogs. Front Vet Sci 2022; 9:880952. [PMID: 35909680 PMCID: PMC9330478 DOI: 10.3389/fvets.2022.880952] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 06/15/2022] [Indexed: 11/20/2022] Open
Abstract
Canine tracheal collapse is a progressive disease in small breed dogs resulting from chronic inflammation of the tracheal mucosal lining. Polyunsaturated fatty acid EAB-277® is one of the nutraceuticals that can alleviate inflammation and oxidative stress. Heart rate variability (HRV) is a prognostic tool related to sympathovagal balance and oxidative stress level, which is widely used with cardiorespiratory diseases. However, the effect of EAB-277® on HRV in tracheal collapse dogs has rarely been investigated. In this study, 26 tracheal collapse dogs were divided into two groups. In the control group, the dogs received the standard treatment, whereas the dogs in the EAB-277® group received standard treatment combined with EAB-277®. After being treated for 5 weeks, changes in radiographic findings, blood profiles, serum malondialdehyde, inflammatory markers, and HRV were evaluated. This study found that clinical signs were improved in both groups (p < 0.05). However, serum malondialdehyde (MDA), Interleukin-6 (IL-6), and Tumor necrosis factor-alpha (TNF-α) were decreased only in the EAB-277® group after treatment for five weeks (p < 0.05) and the mean percent change of MDA, IL-6, and TNF-α at week five compared to baseline in the EAB-277® group was greater than in the control group (p < 0.05). Additionally, greater sympathovagal imbalance indicated by decreased standard deviation of all normal R-R intervals (SDNN) and standard deviation of the averaged R-R intervals for all 5-minutes segments (SDANN) was found in the control group at week five compared to baseline (P < 0.05), whereas EAB-277® improved SDNN and SDANN and decreased low frequency/high-frequency component (LF/HF ratio) after being treated for five weeks (P < 0.05). This study demonstrates that EAB-277® improves clinical signs and attenuates HRV impairment by reducing oxidative stress and inflammation in tracheal collapse dogs.
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Affiliation(s)
- Raktham Mektrirat
- Department of Veterinary Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
- Integrative Research Center for Veterinary Circulatory Sciences, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Thareerat Rueangsri
- Department of Veterinary Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Waraporn Keeratichandacha
- Department of Veterinary Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Sasiwimon Soonsawat
- Veterinary Diagnostic Laboratory, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Chavalit Boonyapakorn
- Integrative Research Center for Veterinary Circulatory Sciences, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
- Department of Companion Animal and Wildlife Clinic, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
- Veterinary Cardiopulmonary Clinic, Small Animal Hospital, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Wanpitak Pongkan
- Department of Veterinary Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
- Integrative Research Center for Veterinary Circulatory Sciences, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
- Veterinary Cardiopulmonary Clinic, Small Animal Hospital, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
- Center of Excellence in Veterinary Biosciences, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
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Identifying a Population of Glial Progenitors That Have Been Mistaken for Neurons in Embryonic Mouse Cortical Culture. eNeuro 2021; 8:ENEURO.0388-20.2020. [PMID: 33483322 PMCID: PMC7986526 DOI: 10.1523/eneuro.0388-20.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 12/16/2020] [Accepted: 12/28/2020] [Indexed: 12/17/2022] Open
Abstract
Experiments in primary culture have helped advance our understanding of the curious phenomenon of cell cycle-related neuronal death. In a differentiated postmitotic cell such as a neuron, aberrant cell cycle reentry is strongly associated with apoptosis. Indeed, in many pathologic conditions, neuronal populations at risk for death are marked by cells engaged in a cell cycle like process. The evidence for this conclusion is typically based on finding MAP2+ cells that are also positive for cell cycle-related proteins (e.g., cyclin D) or have incorporated thymidine analogs such as bromodeoxyuridine (BrdU) or 5-ethynyl-2’-deoxyuridine (EdU) into their nuclei. We now report that we and others may have partly been led astray in pursuing this line of work. Morphometric analysis of mouse embryonic cortical cultures reveals that the size of the “cycling” MAP2+ cells is significantly smaller than those of normal neurons, and their expression of MAP2 is significantly lower. This led us to ask whether, rather than representing fully developed neurons, they more closely resembled precursor-like cells. In support of this idea, we find that these small MAP2+ cells are immunopositive for nestin, a neuronal precursor marker, Olig2, an oligodendrocyte lineage marker, and neural/glial antigen 2 (NG2), an oligodendrocyte precursor marker. Tracking their behavior in culture, we find that they predominantly give rise to GFAP+ astrocytes instead of neurons or oligodendrocytes. These findings argue for a critical reexamination of previous reports of stimuli that lead to neuronal cell cycle-related death in primary cultures.
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Arakaki FH, Xerfan EMS, Galduróz JCF, Tufik S, Andersen ML. Could PCSO-524® be a potential adjuvant treatment to sleep therapy in the management of depression? Psychiatry Res 2021; 295:113590. [PMID: 33276268 DOI: 10.1016/j.psychres.2020.113590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 11/21/2020] [Indexed: 11/30/2022]
Abstract
Sleep is essential in neural system homeostasis due to its regulation of the immunological system and inflammatory cytokines. Poor sleep quality can induce a pro-inflammatory state and aggravate depressive symptoms. Depression has been linked with high levels of peripheral and central pro-inflammatory markers. In this context, we highlight a possible role for PCSO-524®, a nutritional supplement extracted from the New Zealand green lipped mussel that has already been shown to have anti-inflammatory effects, as an adjuvant treatment for depression alongside sleep therapy. Although there are not as yet any studies on its use in treating depression, it has been demonstrated to be a promising treatment in another condition that has been linked with inflammation, attention deficit/hyperactivity disorder, and in some other neurodegenerative disorders. Therefore, PCSO-524®, associated with good sleep quality, could be an option to reinforce depression management.
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Affiliation(s)
- Felipe H Arakaki
- Departamento de Psicobiologia - Universidade Federal de Sao Paulo (UNIFESP), Brazil
| | - Ellen M S Xerfan
- Programa de Pós-Graduação em Medicina Translacional - Universidade Federal de Sao Paulo (UNIFESP), Brazil
| | | | - Sergio Tufik
- Departamento de Psicobiologia - Universidade Federal de Sao Paulo (UNIFESP), Brazil
| | - Monica L Andersen
- Departamento de Psicobiologia - Universidade Federal de Sao Paulo (UNIFESP), Brazil.
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