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Fragkiadaki E, Katsanou L, Vartzoka F, Gravanis A, Pitsikas N. Effects of low doses of the novel dehydroepiandrosterone (DHEA) derivative BNN27 in rat models of anxiety. Psychopharmacology (Berl) 2024; 241:341-350. [PMID: 37917180 PMCID: PMC10806005 DOI: 10.1007/s00213-023-06490-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 10/23/2023] [Indexed: 11/04/2023]
Abstract
RATIONALE Several lines of evidence indicate that the neurosteroid dehydroepiandrosterone (DHEA) is involved in anxiety. BNN27 is a new DHEA derivative lacking steroidogenic effects. The beneficial effects exerted by BNN27 in preclinical models of schizophrenia and memory disorders have been recently reported. OBJECTIVES The present study was designed to investigate the effects of this DHEA novel analog on anxiety-like behavior in rats. METHODS To this end, the light/dark box, the open field, the contextual fear conditioning, and the excessive self-grooming induced by the serotonin 5-HT2c receptor agonist mCPP tests were utilized. RESULTS Animals treated acutely with BNN27 (1, 3, and 6 mg/kg) dose dependently spent more time in the bright compartment of the light/dark box and in the central zone of the open field with respect to their vehicle-treated cohorts. Further, BNN27 reduced freezing behavior and weakened the mCPP-induced excessive self-grooming. CONCLUSIONS Our data indicate that BNN27 is a highly potent anxiolytic agent, as in all studied paradigms it showed anxiolytic-like effects in male rats.
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Affiliation(s)
- Evangelia Fragkiadaki
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences, University of Thessaly, Biopolis, Panepistimiou 3, 415-00, Larissa, Greece
| | - Lamprini Katsanou
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences, University of Thessaly, Biopolis, Panepistimiou 3, 415-00, Larissa, Greece
| | - Foteini Vartzoka
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences, University of Thessaly, Biopolis, Panepistimiou 3, 415-00, Larissa, Greece
| | - Achille Gravanis
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Greece
| | - Nikolaos Pitsikas
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences, University of Thessaly, Biopolis, Panepistimiou 3, 415-00, Larissa, Greece.
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Suzuki K, Ohi Y, Sato T, Tsuda Y, Madokoro Y, Mizuno M, Adachi K, Uchida Y, Haji A, Ojika K, Matsukawa N. Reduction of glutamatergic activity through cholinergic dysfunction in the hippocampus of hippocampal cholinergic neurostimulating peptide precursor protein knockout mice. Sci Rep 2022; 12:19161. [PMID: 36357544 PMCID: PMC9649636 DOI: 10.1038/s41598-022-23846-x] [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: 09/24/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022] Open
Abstract
Cholinergic activation can enhance glutamatergic activity in the hippocampus under pathologic conditions, such as Alzheimer's disease. The aim of the present study was to elucidate the relationship between glutamatergic neural functional decline and cholinergic neural dysfunction in the hippocampus. We report the importance of hippocampal cholinergic neurostimulating peptide (HCNP) in inducing acetylcholine synthesis in the medial septal nucleus. Here, we demonstrate that HCNP-precursor protein (pp) knockout (KO) mice electrophysiologically presented with glutamatergic dysfunction in the hippocampus with age. The impairment of cholinergic function via a decrease in vesicular acetylcholine transporter in the pre-synapse with reactive upregulation of the muscarinic M1 receptor may be partly involved in glutamatergic dysfunction in the hippocampus of HCNP-pp KO mice. The results, in combination with our previous reports that show the reduction of hippocampal theta power through a decrease of a region-specific choline acetyltransferase in the stratum oriens of CA1 and the decrease of acetylcholine concentration in the hippocampus, may indicate the defined cholinergic dysfunction in HCNP-pp KO mice. This may also support that HCNP-pp KO mice are appropriate genetic models for cholinergic functional impairment in septo-hippocampal interactions. Therefore, according to the cholinergic hypothesis, the model mice might are potential partial pathological animal models for Alzheimer's disease.
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Affiliation(s)
- Kengo Suzuki
- grid.260433.00000 0001 0728 1069Department of Neurology, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-Ku, Nagoya, 467-8602 Japan
| | - Yoshiaki Ohi
- grid.411253.00000 0001 2189 9594Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto, Chikusa-Ku, Nagoya, 464-8650 Japan
| | - Toyohiro Sato
- grid.260433.00000 0001 0728 1069Department of Neurology, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-Ku, Nagoya, 467-8602 Japan
| | - Yo Tsuda
- grid.260433.00000 0001 0728 1069Department of Neurology, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-Ku, Nagoya, 467-8602 Japan
| | - Yuta Madokoro
- grid.260433.00000 0001 0728 1069Department of Neurology, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-Ku, Nagoya, 467-8602 Japan
| | - Masayuki Mizuno
- grid.260433.00000 0001 0728 1069Department of Neurology, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-Ku, Nagoya, 467-8602 Japan
| | - Kenichi Adachi
- grid.260433.00000 0001 0728 1069Department of Neurology, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-Ku, Nagoya, 467-8602 Japan
| | - Yuto Uchida
- grid.260433.00000 0001 0728 1069Department of Neurology, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-Ku, Nagoya, 467-8602 Japan
| | - Akira Haji
- grid.411253.00000 0001 2189 9594Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto, Chikusa-Ku, Nagoya, 464-8650 Japan
| | - Kosei Ojika
- grid.260433.00000 0001 0728 1069Department of Neurology, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-Ku, Nagoya, 467-8602 Japan
| | - Noriyuki Matsukawa
- grid.260433.00000 0001 0728 1069Department of Neurology, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-Ku, Nagoya, 467-8602 Japan
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Deficiency in FTSJ1 Affects Neuronal Plasticity in the Hippocampal Formation of Mice. BIOLOGY 2022; 11:biology11071011. [PMID: 36101392 PMCID: PMC9312013 DOI: 10.3390/biology11071011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/01/2022] [Accepted: 07/03/2022] [Indexed: 11/16/2022]
Abstract
Simple Summary Neuronal plasticity refers to the brain’s ability to adapt in response to activity-dependent changes. This process, among others, allows the brain to acquire memory or to compensate for a neurocognitive deficit. We analyzed adult FTSJ1-deficient mice in order to gain insight into the role of FTSJ1 in neuronal plasticity. These mice displayed alterations in the hippocampus (a brain structure that is involved in memory and learning, among other functions) e.g., in the form of changes in dendritic spines. Changes in dendritic spines are considered to represent a morphological hallmark of altered neuronal plasticity, and thus FTSJ1 deficiency might have a direct effect upon the capacity of the brain to adapt to plastic changes. Long-term potentiation (LTP) is an electrophysiological correlate of neuronal plasticity, and is related to learning and to processes attributed to memory. Here we show that LTP in FTSJ1-deficient mice is reduced, hinting at disturbed neuronal plasticity. These findings suggest that FTSJ1 deficiency has an impact on neuronal plasticity not only morphologically but also on the physiological level. Abstract The role of the tRNA methyltransferase FTSJ1 in the brain is largely unknown. We analyzed whether FTSJ1-deficient mice (KO) displayed altered neuronal plasticity. We explored open field behavior (10 KO mice (aged 22–25 weeks)) and 11 age-matched control littermates (WT) and examined mean layer thickness (7 KO; 6 WT) and dendritic spines (5 KO; 5 WT) in the hippocampal area CA1 and the dentate gyrus. Furthermore, long-term potentiation (LTP) within area CA1 was investigated (5 KO; 5 WT), and mass spectrometry (MS) using CA1 tissue (2 each) was performed. Compared to controls, KO mice showed a significant reduction in the mean thickness of apical CA1 layers. Dendritic spine densities were also altered in KO mice. Stable LTP could be induced in the CA1 area of KO mice and remained stable at for at least 1 h, although at a lower level as compared to WTs, while MS data indicated differential abundance of several proteins, which play a role in neuronal plasticity. FTSJ1 has an impact on neuronal plasticity in the murine hippocampal area CA1 at the morphological and physiological levels, which, in conjunction with comparable changes in other cortical areas, might accumulate in disturbed learning and memory functions.
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Fading memories in aging and neurodegeneration: Is p75 neurotrophin receptor a culprit? Ageing Res Rev 2022; 75:101567. [PMID: 35051645 DOI: 10.1016/j.arr.2022.101567] [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: 09/14/2021] [Revised: 12/12/2021] [Accepted: 01/12/2022] [Indexed: 11/22/2022]
Abstract
Aging and age-related neurodegenerative diseases have become one of the major concerns in modern times as cognitive abilities tend to decline when we get older. It is well known that the main cause of this age-related cognitive deficit is due to aberrant changes in cellular, molecular circuitry and signaling pathways underlying synaptic plasticity and neuronal connections. The p75 neurotrophin receptor (p75NTR) is one of the important mediators regulating the fate of the neurons in the nervous system. Its importance in neuronal apoptosis is well documented. However, the mechanisms involving the regulation of p75NTR in synaptic plasticity and cognitive function remain obscure, although cognitive impairment has been associated with a higher expression of p75NTR in neurons. In this review, we discuss the current understanding of how neurons are influenced by p75NTR function to maintain normal neuronal synaptic strength and connectivity, particularly to support learning and memory in the hippocampus. We then discuss the age-associated alterations in neurophysiological mechanisms of synaptic plasticity and cognitive function. Furthermore, we also describe current evidence that has begun to elucidate how p75NTR regulates synaptic changes in aging and age-related neurodegenerative diseases, focusing on the hippocampus. Elucidating the role that p75NTR signaling plays in regulating synaptic plasticity will contribute to a better understanding of cognitive processes and pathological conditions. This will in turn provide novel approaches to improve therapies for the treatment of neurological diseases in which p75NTR dysfunction has been demonstrated.
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Cade S, Zhou XF, Bobrovskaya L. The role of brain-derived neurotrophic factor and the neurotrophin receptor p75NTR in age-related brain atrophy and the transition to Alzheimer's disease. Rev Neurosci 2022; 33:515-529. [PMID: 34982865 DOI: 10.1515/revneuro-2021-0111] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 12/11/2021] [Indexed: 11/15/2022]
Abstract
Alzheimer's disease is a neurodegenerative condition that is potentially mediated by synaptic dysfunction before the onset of cognitive impairments. The disease mostly affects elderly people and there is currently no therapeutic which halts its progression. One therapeutic strategy for Alzheimer's disease is to regenerate lost synapses by targeting mechanisms involved in synaptic plasticity. This strategy has led to promising drug candidates in clinical trials, but further progress needs to be made. An unresolved problem of Alzheimer's disease is to identify the molecular mechanisms that render the aged brain susceptible to synaptic dysfunction. Understanding this susceptibility may identify drug targets which could halt, or even reverse, the disease's progression. Brain derived neurotrophic factor is a neurotrophin expressed in the brain previously implicated in Alzheimer's disease due to its involvement in synaptic plasticity. Low levels of the protein increase susceptibility to the disease and post-mortem studies consistently show reductions in its expression. A desirable therapeutic approach for Alzheimer's disease is to stimulate the expression of brain derived neurotrophic factor and potentially regenerate lost synapses. However, synthesis and secretion of the protein are regulated by complex activity-dependent mechanisms within neurons, which makes this approach challenging. Moreover, the protein is synthesised as a precursor which exerts the opposite effect of its mature form through the neurotrophin receptor p75NTR. This review will evaluate current evidence on how age-related alterations in the synthesis, processing and signalling of brain derived neurotrophic factor may increase the risk of Alzheimer's disease.
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Affiliation(s)
- Shaun Cade
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia
| | - Xin-Fu Zhou
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia
| | - Larisa Bobrovskaya
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia
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Zhang D, Zhao S, Zhang Z, Xu D, Lian D, Wu J, He D, Sun K, Li L. Regulation of the p75 neurotrophin receptor attenuates neuroinflammation and stimulates hippocampal neurogenesis in experimental Streptococcus pneumoniae meningitis. J Neuroinflammation 2021; 18:253. [PMID: 34727939 PMCID: PMC8561879 DOI: 10.1186/s12974-021-02294-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 10/09/2021] [Indexed: 12/12/2022] Open
Abstract
Background Streptococcus pneumoniae meningitis is a destructive central nervous system (CNS) infection with acute and long-term neurological disorders. Previous studies suggest that p75NTR signaling influences cell survival, apoptosis, and proliferation in brain-injured conditions. However, the role of p75NTR signaling in regulating pneumococcal meningitis (PM)-induced neuroinflammation and altered neurogenesis remains largely to be elucidated. Methods p75NTR signaling activation in the pathological process of PM was assessed. During acute PM, a small-molecule p75NTR modulator LM11A-31 or vehicle was intranasally administered for 3 days prior to S. pneumoniae exposure. At 24 h post-infection, clinical severity, histopathology, astrocytes/microglia activation, neuronal apoptosis and necrosis, inflammation-related transcription factors and proinflammatory cytokines/mediators were evaluated. Additionally, p75NTR was knocked down by the adenovirus-mediated short-hairpin RNA (shRNA) to ascertain the role of p75NTR in PM. During long-term PM, the intranasal administration of LM11A-31 or vehicle was continued for 7 days after successfully establishing the PM model. Dynamic changes in inflammation and hippocampal neurogenesis were assessed. Results Our results revealed that both 24 h (acute) and 7, 14, 28 day (long-term) groups of infected rats showed increased p75NTR expression in the brain. During acute PM, modulation of p75NTR through pretreatment of PM model with LM11A-31 significantly alleviated S. pneumoniae-induced clinical severity, histopathological injury and the activation of astrocytes and microglia. LM11A-31 pretreatment also significantly ameliorated neuronal apoptosis and necrosis. Moreover, we found that blocking p75NTR with LM11A-31 decreased the expression of inflammation-related transcription factors (NF-κBp65, C/EBPβ) and proinflammatory cytokines/mediators (IL-1β, TNF-α, IL-6 and iNOS). Furthermore, p75NTR knockdown induced significant changes in histopathology and inflammation-related transcription factors expression. Importantly, long-term LM11A-31 treatment accelerated the resolution of PM-induced inflammation and significantly improved hippocampal neurogenesis. Conclusion Our findings suggest that the p75NTR signaling plays an essential role in the pathogenesis of PM. Targeting p75NTR has beneficial effects on PM rats by alleviating neuroinflammation and promoting hippocampal neurogenesis. Thus, the p75NTR signaling may be a potential therapeutic target to improve the outcome of PM. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-021-02294-w.
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Affiliation(s)
- Dandan Zhang
- Department of Pediatric Neurology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Kongjiang Road 1665, Shanghai, 200092, China
| | - Shengnan Zhao
- Department of Pediatric Neurology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Kongjiang Road 1665, Shanghai, 200092, China
| | - Zhijie Zhang
- Department of Pediatric Neurology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Kongjiang Road 1665, Shanghai, 200092, China
| | - Danfeng Xu
- Department of Pediatric Neurology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Kongjiang Road 1665, Shanghai, 200092, China
| | - Di Lian
- Department of Pediatric Neurology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Kongjiang Road 1665, Shanghai, 200092, China
| | - Jing Wu
- Department of Pediatric Neurology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Kongjiang Road 1665, Shanghai, 200092, China
| | - Dake He
- Department of Pediatric Neurology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Kongjiang Road 1665, Shanghai, 200092, China
| | - Kun Sun
- Department of Pediatric Cardiology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Kongjiang Road 1665, Shanghai, 200092, China.
| | - Ling Li
- Department of Pediatric Neurology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Kongjiang Road 1665, Shanghai, 200092, China.
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7
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Ma X, Vuyyuru H, Munsch T, Endres T, Lessmann V, Meis S. ProBDNF Dependence of LTD and Fear Extinction Learning in the Amygdala of Adult Mice. Cereb Cortex 2021; 32:1350-1364. [PMID: 34470044 DOI: 10.1093/cercor/bhab265] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 07/14/2021] [Accepted: 07/15/2021] [Indexed: 11/12/2022] Open
Abstract
Neurotrophins are secreted proteins that control survival, differentiation, and synaptic plasticity. While mature neurotrophins regulate these functions via tyrosine kinase signaling (Trk), uncleaved pro-neurotrophins bind preferentially to the p75 neurotrophin receptor (p75NTR) and often exert opposite effects to those of mature neurotrophins. In the amygdala, brain-derived neurotrophic factor (BDNF) enables long-term potentiation as well as fear and fear extinction learning. In the present study, we focused on the impact of mature BDNF and proBDNF signaling on long-term depression (LTD) in the lateral amygdala (LA). Hence, we conducted extracellular field potential recordings in an in vitro slice preparation and recorded LTD in cortical and thalamic afferents to the LA. LTD was unchanged by acute block of BDNF/TrkB signaling. In contrast, LTD was inhibited by blocking p75NTR signaling, by disinhibition of the proteolytic cleavage of proBDNF into mature BDNF, and by preincubation with a function-blocking anti-proBDNF antibody. Since LTD-like processes in the amygdala are supposed to be related to fear extinction learning, we locally inhibited p75NTR signaling in the amygdala during or after fear extinction training, resulting in impaired fear extinction memory. Overall, these results suggest that in the amygdala proBDNF/p75NTR signaling plays a pivotal role in LTD and fear extinction learning.
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Affiliation(s)
- Xiaoyun Ma
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany
| | - Harish Vuyyuru
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany
| | - Thomas Munsch
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany.,Center for Behavioral Brain Sciences, Universitätsplatz 2, D-39106 Magdeburg, Germany
| | - Thomas Endres
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany
| | - Volkmar Lessmann
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany.,Center for Behavioral Brain Sciences, Universitätsplatz 2, D-39106 Magdeburg, Germany
| | - Susanne Meis
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany.,Center for Behavioral Brain Sciences, Universitätsplatz 2, D-39106 Magdeburg, Germany
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Schott BH, Kronenberg G, Schmidt U, Düsedau HP, Ehrentraut S, Geisel O, von Bohlen Und Halbach O, Gass P, Dunay IR, Hellweg R. Robustly High Hippocampal BDNF levels under Acute Stress in Mice Lacking the Full-length p75 Neurotrophin Receptor. PHARMACOPSYCHIATRY 2021; 54:205-213. [PMID: 33592642 DOI: 10.1055/a-1363-1680] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Brain-derived neurotrophic factor (BDNF) exerts its effects on neural plasticity via 2 distinct receptor types, the tyrosine kinase TrkB and the p75 neurotrophin receptor (p75NTR). The latter can promote inflammation and cell death while TrkB is critically involved in plasticity and memory, particularly in the hippocampus. Acute and chronic stress have been associated with suppression of hippocampal BDNF expression and impaired hippocampal plasticity. We hypothesized that p75NTR might be involved in the hippocampal stress response, in particular in stress-induced BDNF suppression, which might be accompanied by increased neuroinflammation. METHOD We assessed hippocampal BDNF protein concentrations in wild-type mice compared that in mice lacking the long form of the p75NTR (p75NTRExIII-/-) with or without prior exposure to a 1-hour restraint stress challenge. Hippocampal BDNF concentrations were measured using an optimized ELISA. Furthermore, whole-brain mRNA expression of pro-inflammatory interleukin-6 (Il6) was assessed with RT-PCR. RESULTS Deletion of full-length p75NTR was associated with higher hippocampal BDNF protein concentration in the stress condition, suggesting persistently high hippocampal BDNF levels in p75NTR-deficient mice, even under stress. Stress elicited increased whole-brain Il6 mRNA expression irrespective of genotype; however, p75NTRExIII-/- mice showed elevated baseline Il6 expression and thus a lower relative increase. CONCLUSIONS Our results provide evidence for a role of p75NTR signaling in the regulation of hippocampal BDNF levels, particularly under stress. Furthermore, p75NTR signaling modulates baseline but not stress-related Il6 gene expression in mice. Our findings implicate p75NTR signaling as a potential pathomechanism in BDNF-dependent modulation of risk for neuropsychiatric disorders.
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Affiliation(s)
- Björn H Schott
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen (UMG), Göttingen, Germany.,Department of Psychiatry and Psychotherapy, Charité Universitätsmedizin Berlin, Berlin, Germany.,Leibniz Institute for Neurobiology, Department of Behavioral Neurology, Magdeburg, Germany.,German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | - Golo Kronenberg
- Department of Psychiatry and Psychotherapy, Charité Universitätsmedizin Berlin, Berlin, Germany.,University of Leicester and Leicestershire Partnership NHS Trust, Leicester, United Kingdom
| | - Ulrike Schmidt
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen (UMG), Göttingen, Germany.,Department of Psychiatry and Psychotherapy, University Medical Center Bonn, Bonn, Germany
| | - Henning P Düsedau
- Institute of Inflammation and Neurodegeneration, Otto von Guericke University, Magdeburg, Germany
| | - Stefanie Ehrentraut
- Institute of Inflammation and Neurodegeneration, Otto von Guericke University, Magdeburg, Germany
| | - Olga Geisel
- Department of Psychiatry and Psychotherapy, Charité Universitätsmedizin Berlin, Berlin, Germany
| | | | - Peter Gass
- Central Institute for Mental Health, Department of Psychiatry and Psychotherapy, Heidelberg University, Mannheim Faculty, Germany
| | - Ildiko Rita Dunay
- Institute of Inflammation and Neurodegeneration, Otto von Guericke University, Magdeburg, Germany
| | - Rainer Hellweg
- Department of Psychiatry and Psychotherapy, Charité Universitätsmedizin Berlin, Berlin, Germany
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9
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Qin Z, Gonsalvez DG, Wood RJ, Daemi F, Yoo S, Ivanusic JJ, Coulson EJ, Murray SS, Xiao J. Partial deletion of p75 NTR in large-diameter DRG neurons exerts no influence upon the survival of peripheral sensory neurons in vivo. J Neurosci Res 2020; 98:1987-1998. [PMID: 32585763 DOI: 10.1002/jnr.24665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 04/20/2020] [Accepted: 05/14/2020] [Indexed: 01/19/2023]
Abstract
The p75 neurotrophin receptor (p75NTR ) is required for maintaining peripheral sensory neuron survival and function; however, the underlying cellular mechanism remains unclear. The general view is that expression of p75NTR by the neuron itself is required for maintaining sensory neuron survival and myelination in the peripheral nervous system (PNS). Adopting a neuronal-specific conditional knockout strategy, we demonstrate the partial depletion of p75NTR in neurons exerts little influence upon maintaining sensory neuron survival and peripheral nerve myelination in health and after demyelinating neuropathy. Our data show that the density and total number of dorsal root ganglion (DRG) neurons in 2-month-old mice is not affected following the deletion of p75NTR in large-diameter myelinating neurons, as assessed by stereology. Adopting experimental autoimmune neuritis induced in adult male mice, an animal model of demyelinating peripheral neuropathy, we identify that deleting p75NTR in myelinating neurons exerts no influence upon the disease progression, the total number of DRG neurons, and the extent of myelin damage in the sciatic nerve, indicating that the expression of neuronal p75NTR is not essential for maintaining peripheral neuron survival and myelination after a demyelinating insult in vivo. Together, results of this study suggest that the survival and myelination of peripheral sensory neurons is independent of p75NTR expressed by a subtype of neurons in vivo. Thus, our findings provide new insights into the mechanism underpinning p75NTR -mediated neuronal survival in the PNS.
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Affiliation(s)
- Zuoheng Qin
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - David G Gonsalvez
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Rhiannon J Wood
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Fatemeh Daemi
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Sangwon Yoo
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Jason J Ivanusic
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Elizabeth J Coulson
- School of Biomedical Sciences, Queensland University, Brisbane, QLD, Australia
| | - Simon S Murray
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Junhua Xiao
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
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10
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Neurotrophin signalling in amygdala-dependent cued fear learning. Cell Tissue Res 2020; 382:161-172. [PMID: 32845430 PMCID: PMC7529623 DOI: 10.1007/s00441-020-03260-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 07/13/2020] [Indexed: 12/20/2022]
Abstract
The amygdala is a central hub for fear learning assessed by Pavlovian fear conditioning. Indeed, the prevailing hypothesis that learning and memory are mediated by changes in synaptic strength was shown most convincingly at thalamic and cortical afferents to the lateral amygdala. The neurotrophin brain-derived neurotrophic factor (BDNF) is known to regulate synaptic plasticity and memory formation in many areas of the mammalian brain including the amygdala, where BDNF signalling via tropomyosin-related kinase B (TrkB) receptors is prominently involved in fear learning. This review updates the current understanding of BDNF/TrkB signalling in the amygdala related to fear learning and extinction. In addition, actions of proBDNF/p75NTR and NGF/TrkA as well as NT-3/TrkC signalling in the amygdala are introduced.
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11
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Yang WJ, Yan AZ, Xu YJ, Guo XY, Fu XG, Li D, Liao J, Zhang D, Lan FH. Further identification of a 140bp sequence from amid intron 9 of human FMR1 gene as a new exon. BMC Genet 2020; 21:63. [PMID: 32552710 PMCID: PMC7301526 DOI: 10.1186/s12863-020-00870-2] [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: 01/07/2020] [Accepted: 06/09/2020] [Indexed: 11/24/2022] Open
Abstract
Background The disease gene of fragile X syndrome, FMR1 gene, encodes fragile X mental retardation protein (FMRP). The alternative splicing (AS) of FMR1 can affect the structure and function of FMRP. However, the biological functions of alternatively spliced isoforms remain elusive. In a previous study, we identified a new 140bp exon from the intron 9 of human FMR1 gene. In this study, we further examined the biological functions of this new exon and its underlying signaling pathways. Results qRT-PCR results showed that this novel exon is commonly expressed in the peripheral blood of normal individuals. Comparative genomics showed that sequences paralogous to the 140 bp sequence only exist in the genomes of primates. To explore the biological functions of the new transcript, we constructed recombinant eukaryotic expression vectors and lentiviral overexpression vectors. Results showed that the spliced transcript encoded a truncated protein which was expressed mainly in the cell nucleus. Additionally, several genes, including the BEX1 gene involved in mGluR-LTP or mGluR-LTD signaling pathways were significantly influenced when the truncated FMRP was overexpressed. Conclusions our work identified a new exon from amid intron 9 of human FMR1 gene with wide expression in normal healthy individuals, which emphasizes the notion that the AS of FMR1 gene is complex and may in a large part account for the multiple functions of FMRP.
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Affiliation(s)
- Wen-Jing Yang
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China.,Present addresses: Department of Laboratory Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Ai-Zhen Yan
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China
| | - Yong-Jun Xu
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China
| | - Xiao-Yan Guo
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China.,Present addresses: Department of Laboratory Medicine, Fuzhou No. 2 Hospital Affiliated Xiamen University, Fuzhou, Fujian, 350007, People's Republic of China
| | - Xian-Guo Fu
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China.,Present addresses: Department of Laboratory Medicine, Ningde Municipal Hospital, Fujian Medical University, Ningde City, 352100, Fujian Province, China
| | - Dan Li
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China
| | - Juan Liao
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China.,Present addresses: Department of Laboratory Medicine, Fujian University of Traditional Chinese Medicine Affiliated People's Hospital, Fuzhou, 350001, Fujian, China
| | - Duo Zhang
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China
| | - Feng-Hua Lan
- Department of Clinical Genetics and Experimental Medicine, 900th Hospital of the Joint Logistics Force, Xiamen University School of Medicine, 156 Xi'erhuanbei Road, Fuzhou City, Fujian Province, 350025, People's Republic of China.
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Choi MR, Jin YB, Bang SH, Im CN, Lee Y, Kim HN, Chang KT, Lee SR, Kim DJ. Age-related Effects of Heroin on Gene Expression in the Hippocampus and Striatum of Cynomolgus Monkeys. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE 2020; 18:93-108. [PMID: 31958910 PMCID: PMC7006971 DOI: 10.9758/cpn.2020.18.1.93] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/02/2019] [Accepted: 05/03/2019] [Indexed: 11/18/2022]
Abstract
Objective The aim of this study was to investigate differentially expressed genes and their functions in the hippocampus and striatum after heroin administration in cynomolgus macaques of different ages. Methods Cynomolgus monkeys were divided by age as follows: 1 year (A1, n = 2); 3 to 4 years (A2, n = 2); 6 to 8 years (A3, n = 2); and older than 11 years (A4, n = 2). After heroin was injected intramuscularly into the monkeys (0.6 mg/kg), we performed large-scale transcriptome profiling in the hippocampus (H) and striatum (S) using RNA sequencing technology. Some genes were validated with real-time quantitative PCR. Results In the hippocampus, the gene expression of A1H was similar to that of A4H, while the gene expression of A2H was similar to that of A3H. Genes associated with the mitogen-activated protein kinase signaling pathway (STMN1, FGF14, and MAPT) and γ-aminobutyric acid-ergic synapses (GABBR2 and GAD1) were differentially expressed among control and heroin-treated animals. Differential gene expression between A1S and A4S was the least significant, while differential gene expression between A3S and A2S was the most significant. Genes associated with the neurotrophin signaling pathway (NTRK1 and NGFR), autophagy (ATG5), and dopaminergic synapses (AKT1) in the striatum were differentially expressed among control and heroin-treated animals. Conclusion These results suggest that even a single heroin exposure can cause differential gene expression in the hippocampus and striatum of nonhuman primates at different ages.
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Affiliation(s)
- Mi Ran Choi
- Department of Psychiatry, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Yeung-Bae Jin
- National Primate Research Center (NPRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
| | - Sol Hee Bang
- Department of Psychiatry, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Chang-Nim Im
- Department of Psychiatry, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Youngjeon Lee
- National Primate Research Center (NPRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
| | - Han-Na Kim
- National Primate Research Center (NPRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
| | - Kyu-Tae Chang
- National Primate Research Center (NPRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea.,Department of Functional Genomics, University of Science and Technology, Daejeon, Korea
| | - Sang-Rae Lee
- National Primate Research Center (NPRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea.,Department of Functional Genomics, University of Science and Technology, Daejeon, Korea
| | - Dai-Jin Kim
- Department of Psychiatry, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
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Zhao M, Wang Y, Li G, Li J, Yang K, Liu C, Wen X, Song J. The role and potential mechanism of p75NTR in mineralization via in vivo p75NTR knockout mice and in vitro ectomesenchymal stem cells. Cell Prolif 2020; 53:e12758. [PMID: 31922317 PMCID: PMC7048213 DOI: 10.1111/cpr.12758] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/03/2019] [Accepted: 12/19/2019] [Indexed: 01/15/2023] Open
Abstract
OBJECTIVE The aim of this study is to investigate the role and potential mechanism of p75NTR in mineralization in vivo using p75NTR-knockout mice and in vitro using ectomesenchymal stem cells (EMSCs). MATERIALS AND METHODS Femur bone mass and daily incisor mineralization speed were assessed in an in vivo p75NTR-knockout mouse model. The molecular signatures alkaline phosphatase (ALP), collagen type 1 (Col1), melanoma-associated antigen (Mage)-D1, bone sialoprotein (BSP), osteocalcin (OCN), osteopontin (OPN), distal-less homeobox 1 (Dlx1) and Msh homeobox 1 (Msx1) were examined in vitro in EMSCs isolated from p75NTR+/+ and p75NTRExIII-/- mice. RESULTS p75NTR-knockout mice were smaller in body size than heterozygous and wild-type mice. Micro-computed tomography and structural quantification showed that the osteogenic ability of p75NTRExIII -knockout mice was significantly decreased compared with that of wild-type mice (P < .05). Weaker ALP and alizarin red staining and reduced expression of ALP, Col1, Runx2, BSP, OCN and OPN were also observed in p75NTRExIII-/- EMSCs. Moreover, the distance between calcein fluorescence bands in p75NTRExIII -knockout mice was significantly smaller than that in wild type and heterozygous mice (P < .05), indicating the lower daily mineralization speed of incisors in p75NTRExIII -knockout mice. Further investigation revealed a positive correlation between p75NTR and Mage-D1, Dlx1, and Msx1. CONCLUSION p75NTR not only promotes osteogenic differentiation and tissue mineralization, but also shows a possible relationship with the circadian rhythm of dental hard tissue formation.
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Affiliation(s)
- Manzhu Zhao
- College of StomatologyChongqing Key Laboratory for Oral Diseases and Biomedical SciencesChongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher EducationChongqing Medical UniversityChongqingChina
| | - Yingying Wang
- Department of StomatologyDaping Hospital & Research Institute of SurgeryThird Military Medical UniversityChongqingChina
| | - Gang Li
- Department of StomatologyDaping Hospital & Research Institute of SurgeryThird Military Medical UniversityChongqingChina
| | - Jun Li
- Department of StomatologyDaping Hospital & Research Institute of SurgeryThird Military Medical UniversityChongqingChina
| | - Kun Yang
- Department of StomatologyDaping Hospital & Research Institute of SurgeryThird Military Medical UniversityChongqingChina
| | - Chang Liu
- College of StomatologyChongqing Key Laboratory for Oral Diseases and Biomedical SciencesChongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher EducationChongqing Medical UniversityChongqingChina
| | - Xiujie Wen
- Department of StomatologyDaping Hospital & Research Institute of SurgeryThird Military Medical UniversityChongqingChina
- Department of OrthodonticsHospital of StomatologySouthwest Medical UniversityLuzhouChina
| | - Jinlin Song
- College of StomatologyChongqing Key Laboratory for Oral Diseases and Biomedical SciencesChongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher EducationChongqing Medical UniversityChongqingChina
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Modulation of the p75 neurotrophin receptor suppresses age-related basal forebrain cholinergic neuron degeneration. Sci Rep 2019; 9:5273. [PMID: 30918278 PMCID: PMC6437186 DOI: 10.1038/s41598-019-41654-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 02/08/2019] [Indexed: 11/19/2022] Open
Abstract
Age-related degeneration of basal forebrain cholinergic neurons (BFCNs) is linked to cognitive impairment. The p75 neurotrophin receptor (p75NTR) has been proposed to mediate neuronal degeneration in aging. Therefore, we tested the hypothesis that modifying p75NTR function would prevent or reverse aging-related neuronal degeneration using LM11A-31, a small molecule p75NTR modulator that downregulates degenerative and upregulates trophic receptor-associated signaling. Morphological analysis in mice showed loss of BFCN area detectable by 18 months of age. Oral administration of LM11A-31 from age 15 to 18 months resulted in a dose-related preservation of BFCN area and one month of treatment from 17 to 18 months also preserved cell area. To evaluate reversal of established neuronal atrophy, animals were treated from 21 to 25 months of age. Treatment was associated with an increase of cell size to a mean area larger than that observed at 18 months, accompanied by increases in mean MS/VDB neurite length, as well as increased cholinergic fiber density and synaptophysin pre-synaptic marker levels in the hippocampus. These findings support the idea that modulation of p75NTR activity can prevent and potentially reverse age-associated BFCN degeneration. Moreover, this may be achieved therapeutically with orally bioavailable agents such as LM11A-31.
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Abstract
The solute carrier (SLC) group of membrane transport proteins includes about 400 members organized into more than 50 families. The SLC family that comprises nucleoside-sugar transporters is referred to as SLC35. One of the members of this family is SLC35F1. The function of SLC35F1 is still unknown; however, recent studies demonstrated that SLC35F1 mRNA is highly expressed in the brain and in the kidney. Therefore, we examine the distribution of Slc35f1 protein in the murine forebrain using immunohistochemistry. We could demonstrate that Slc35f1 is highly expressed in the adult mouse brain in a variety of different brain structures, including the cortex, hippocampus, amygdala, thalamus, basal ganglia, and hypothalamus. To examine the possible roles of Slc35f1 and its subcellular localization, we used an in vitro glioblastoma cell line expressing Slc35f1. Co-labeling experiments were performed to reveal the subcellular localization of Slc35f1. Our results indicate that Slc35f1 neither co-localizes with markers for the Golgi apparatus nor with markers for the endoplasmic reticulum. Time-lapse microscopy of living cells revealed that Slc35f1-positive structures are highly dynamic and resemble vesicles. Using super-resolution microscopy, these Slc35f1-positive spots clearly co-localize with the recycling endosome marker Rab11.
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Regulation of cholinergic basal forebrain development, connectivity, and function by neurotrophin receptors. Neuronal Signal 2019; 3:NS20180066. [PMID: 32269831 PMCID: PMC7104233 DOI: 10.1042/ns20180066] [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: 10/22/2018] [Revised: 01/15/2019] [Accepted: 01/15/2019] [Indexed: 12/11/2022] Open
Abstract
Cholinergic basal forebrain (cBF) neurons are defined by their expression of the p75 neurotrophin receptor (p75NTR) and tropomyosin-related kinase (Trk) neurotrophin receptors in addition to cholinergic markers. It is known that the neurotrophins, particularly nerve growth factor (NGF), mediate cholinergic neuronal development and maintenance. However, the role of neurotrophin signalling in regulating adult cBF function is less clear, although in dementia, trophic signalling is reduced and p75NTR mediates neurodegeneration of cBF neurons. Here we review the current understanding of how cBF neurons are regulated by neurotrophins which activate p75NTR and TrkA, B or C to influence the critical role that these neurons play in normal cortical function, particularly higher order cognition. Specifically, we describe the current evidence that neurotrophins regulate the development of basal forebrain neurons and their role in maintaining and modifying mature basal forebrain synaptic and cortical microcircuit connectivity. Understanding the role neurotrophin signalling plays in regulating the precision of cholinergic connectivity will contribute to the understanding of normal cognitive processes and will likely provide additional ideas for designing improved therapies for the treatment of neurological disease in which cholinergic dysfunction has been demonstrated.
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Buhusi M, Etheredge C, Granholm AC, Buhusi CV. Increased Hippocampal ProBDNF Contributes to Memory Impairments in Aged Mice. Front Aging Neurosci 2017; 9:284. [PMID: 28912711 PMCID: PMC5583170 DOI: 10.3389/fnagi.2017.00284] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 08/14/2017] [Indexed: 01/27/2023] Open
Abstract
Memory decline during aging or accompanying neurodegenerative diseases, represents a major health problem. Neurotrophins have long been considered relevant to the mechanisms of aging-associated cognitive decline and neurodegeneration. Mature Brain-Derived Neurotrophic Factor (BDNF) and its precursor (proBDNF) can both be secreted in response to neuronal activity and exert opposing effects on neuronal physiology and plasticity. In this study, biochemical analyses revealed that increased levels of proBDNF are present in the aged mouse hippocampus relative to young and that the level of hippocampal proBDNF inversely correlates with the ability to perform in a spatial memory task, the water radial arm maze (WRAM). To ascertain the role of increased proBDNF levels on hippocampal function and memory we performed infusions of proBDNF into the CA1 region of the dorsal hippocampus in male mice trained in the WRAM paradigm: In well-performing aged mice, intra-hippocampal proBDNF infusions resulted in a progressive and significant impairment of memory performance. This impairment was associated with increased p-cofilin levels, an important regulator of dendritic spines and synapse physiology. On the other hand, in poor performers, intra-hippocampal infusions of TAT-Pep5, a peptide which blocks the interaction between the p75 Neurotrophin Receptor (p75NTR) and RhoGDI, significantly improved learning and memory, while saline infusions had no effect. Our results support a role for proBDNF and its receptor p75NTR in aging-related memory impairments.
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Affiliation(s)
- Mona Buhusi
- Interdisciplinary Program in Neuroscience, Department of Psychology, Utah State UniversityLogan, UT, United States
| | - Chris Etheredge
- Department of Neuroscience, Medical University of South CarolinaCharleston, SC, United States
| | - Ann-Charlotte Granholm
- Department of Neuroscience, Medical University of South CarolinaCharleston, SC, United States
| | - Catalin V Buhusi
- Interdisciplinary Program in Neuroscience, Department of Psychology, Utah State UniversityLogan, UT, United States
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