1
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Deng C, Chen H. Brain-derived neurotrophic factor/tropomyosin receptor kinase B signaling in spinal muscular atrophy and amyotrophic lateral sclerosis. Neurobiol Dis 2024; 190:106377. [PMID: 38092270 DOI: 10.1016/j.nbd.2023.106377] [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: 09/17/2023] [Revised: 11/15/2023] [Accepted: 12/10/2023] [Indexed: 12/23/2023] Open
Abstract
Tropomyosin receptor kinase B (TrkB) and its primary ligand brain-derived neurotrophic factor (BDNF) are expressed in the neuromuscular system, where they affect neuronal survival, differentiation, and functions. Changes in BDNF levels and full-length TrkB (TrkB-FL) signaling have been revealed in spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS), two common forms of motor neuron diseases that are characterized by defective neuromuscular junctions in early disease stages and subsequently progressive muscle weakness. This review summarizes the current understanding of BDNF/TrkB-FL-related research in SMA and ALS, with an emphasis on their alterations in the neuromuscular system and possible BDNF/TrkB-FL-targeting therapeutic strategies. The limitations of current studies and future directions are also discussed, giving the hope of discovering novel and effective treatments.
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Affiliation(s)
- Chunchu Deng
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hong Chen
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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2
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Rifai OM, O’Shaughnessy J, Dando OR, Munro AF, Sewell MDE, Abrahams S, Waldron FM, Sibley CR, Gregory JM. Distinct neuroinflammatory signatures exist across genetic and sporadic amyotrophic lateral sclerosis cohorts. Brain 2023; 146:5124-5138. [PMID: 37450566 PMCID: PMC10690026 DOI: 10.1093/brain/awad243] [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: 03/26/2023] [Revised: 05/31/2023] [Accepted: 06/25/2023] [Indexed: 07/18/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive loss of upper and lower motor neurons. ALS is on a pathogenetic disease spectrum with frontotemporal dementia, referred to as ALS-frontotemporal spectrum disorder (ALS-FTSD). For mutations associated with ALS-FTSD, such as the C9orf72 hexanucleotide repeat expansion, the molecular factors associated with heterogeneity along this spectrum require further characterization. Here, using a targeted NanoString molecular barcoding approach, we interrogate neuroinflammatory dysregulation and heterogeneity at the level of gene expression in post-mortem motor cortex tissue from a cohort of clinically heterogeneous C9-ALS-FTSD cases. We identified 20 dysregulated genes in C9-ALS-FTSD, with enrichment of microglial and inflammatory response gene sets. Two genes with significant correlations to available clinical metrics were selected for validation: FKBP5, a correlate of cognitive function, and brain-derived neurotrophic factor (BDNF), a correlate of disease duration. FKBP5 and its signalling partner, NF-κB, appeared to have a cell type-specific staining distribution, with activated (i.e. nuclear) NF-κB immunoreactivity in C9-ALS-FTSD. Expression of BDNF, a correlate of disease duration, was confirmed to be higher in individuals with long compared to short disease duration using BaseScope™ in situ hybridization. Our analyses also revealed two distinct neuroinflammatory panel signatures (NPS), NPS1 and NPS2, delineated by the direction of expression of proinflammatory, axonal transport and synaptic signalling pathways. We compared NPS between C9-ALS-FTSD cases and those from sporadic ALS and SOD1-ALS cohorts and identified NPS1 and NPS2 across all cohorts. Moreover, a subset of NPS was also able to separate publicly available RNA sequencing data from independent C9-ALS and sporadic ALS cohorts into two inflammatory subgroups. Importantly, NPS subgroups did not clearly segregate with available demographic, genetic, clinical or pathological features, highlighting the value of molecular stratification in clinical trials for inflammatory subgroup identification. Our findings thus underscore the importance of tailoring therapeutic approaches based on distinct molecular signatures that exist between and within ALS-FTSD cohorts.
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Affiliation(s)
- Olivia M Rifai
- Translational Neuroscience PhD Programme, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
- UK Dementia Research Institute, University of Edinburgh, Edinburgh, EH16 4SB, UK
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Judi O’Shaughnessy
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Owen R Dando
- UK Dementia Research Institute, University of Edinburgh, Edinburgh, EH16 4SB, UK
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XF, UK
| | - Alison F Munro
- Cancer Research UK Edinburgh Centre, Institute of Genetics and Cancer, The University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Michael D E Sewell
- Translational Neuroscience PhD Programme, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
- UK Dementia Research Institute, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Sharon Abrahams
- Human Cognitive Neuroscience-Psychology, School of Philosophy, Psychology and Language Sciences, University of Edinburgh, Edinburgh, EH8 9AD, UK
| | - Fergal M Waldron
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD, UK
| | - Christopher R Sibley
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XF, UK
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, The King’s Buildings, Edinburgh, EH9 3FF, UK
| | - Jenna M Gregory
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD, UK
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3
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Zhang Y, Zhang D, Chen L, Zhou J, Ren B, Chen H. The progress of autoimmune hepatitis research and future challenges. Open Med (Wars) 2023; 18:20230823. [PMID: 38025543 PMCID: PMC10655690 DOI: 10.1515/med-2023-0823] [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: 04/17/2023] [Revised: 09/24/2023] [Accepted: 09/28/2023] [Indexed: 12/01/2023] Open
Abstract
Autoimmune hepatitis (AIH) is a chronic liver inflammatory disease with various immune system manifestations, showing a global trend of increased prevalence. AIH is diagnosed through histological abnormalities, clinical manifestations, and biochemical indicators. The biochemical markers involve interfacial hepatitis, transaminase abnormalities, positive autoantibodies, etc. Although AIH pathogenesis is unclear, gene mutations and immunological factors could be the leading factors. AIH usually presents as a chronic liver disease and sometimes as acute hepatitis, making it challenging to distinguish it from drug-related hepatitis due to similar clinical symptoms. Normalizing transaminases and serum IgG levels is essential in assessing the remission status of AIH treatment. Glucocorticoids and azathioprine are the first-line AIH treatment, with lifelong maintenance therapy in some patients. The quality of life and survival can be improved after appropriate treatment. However, certain limitations jeopardize the quality of treatment, including long treatment cycles, side effects, poor patient compliance, and inability to inhibit liver fibrosis and cirrhosis. Accurate AIH animal models will help us understand the pathophysiology of the disease while providing fresh perspectives for avoiding and treating AIH. This review will help us understand AIH better, from the cellular and molecular causes to the clinical features, and will provide insight into new therapy techniques with fewer side effects.
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Affiliation(s)
- Yang Zhang
- Graduate Department of Zhejiang Chinese Medicine University, Hangzhou, Zhejiang, China
- Department of Infectious Diseases, Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, China
| | - Dehe Zhang
- Department of Infectious Diseases, Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, China
| | - Ling Chen
- Department of Infectious Diseases, Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, China
| | - Jing Zhou
- Department of Infectious Diseases, Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, China
| | - Binbin Ren
- Department of Infectious Diseases, Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, China
| | - Haijun Chen
- Department of Infectious Diseases, Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, China
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4
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Yang L, Cheng Y, Zhu Y, Cui L, Li X. The Serotonergic System and Amyotrophic Lateral Sclerosis: A Review of Current Evidence. Cell Mol Neurobiol 2023:10.1007/s10571-023-01320-0. [PMID: 36729314 DOI: 10.1007/s10571-023-01320-0] [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: 08/03/2022] [Accepted: 01/18/2023] [Indexed: 02/03/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the premature death of motor neurons. Serotonin (5-HT) is a crucial neurotransmitter, and its dysfunction, whether as a contributor or by-product, has been implicated in ALS pathogenesis. Here, we summarize current evidence linking serotonergic alterations to ALS, including results from post-mortem and neuroimaging studies, biofluid testing, and studies of ALS animal models. We also discuss the possible role of 5-HT in modulating some important mechanisms of ALS (i.e. glutamate excitotoxity and neuroinflammation) and in regulating ALS phenotypes (i.e. breathing dysfunction and metabolic defects). Finally, we discuss the promise and limitations of the serotonergic system as a target for the development of ALS biomarkers and therapeutic approaches. However, due to a relative paucity of data and standardized methodologies in previous studies, proper interpretation of existing results remains a challenge. Future research is needed to unravel the mechanisms linking serotonergic pathways and ALS and to provide valid, reproducible, and translatable findings.
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Affiliation(s)
- Lu Yang
- Department of Neurology, Peking Union Medical College Hospital (PUMCH), The Transformation Medical Center of PUMC, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Beijing, 100005, China
| | - Yanfei Cheng
- Department of Neurology, Peking Union Medical College Hospital (PUMCH), The Transformation Medical Center of PUMC, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Beijing, 100005, China
| | - Yicheng Zhu
- Department of Neurology, Peking Union Medical College Hospital (PUMCH), The Transformation Medical Center of PUMC, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Beijing, 100005, China.,Neuroscience Center, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Beijing, China
| | - Liying Cui
- Department of Neurology, Peking Union Medical College Hospital (PUMCH), The Transformation Medical Center of PUMC, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Beijing, 100005, China.,Neuroscience Center, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Beijing, China
| | - Xiaoguang Li
- Department of Neurology, Peking Union Medical College Hospital (PUMCH), The Transformation Medical Center of PUMC, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Beijing, 100005, China. .,Neuroscience Center, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Beijing, China.
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5
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Maxwell MN, Marullo AL, Slyne AD, Lucking EF, O'Halloran KD. Ventilatory Effects of Acute Intermittent Hypoxia in Conscious Dystrophic Mice. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1427:83-88. [PMID: 37322338 DOI: 10.1007/978-3-031-32371-3_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Exposure to acute intermittent hypoxia (AIH) elicits a form of respiratory plasticity known as long-term facilitation (LTF). Interest has grown in developing AIH interventions to treat ventilatory insufficiency, with promising results in spinal cord injury and amyotrophic lateral sclerosis. Therapeutic AIH may have application in neuromuscular disorders including muscular dystrophies. We sought to establish hypoxic ventilatory responsiveness and the expression of ventilatory LTF in X-linked muscular dystrophy (mdx) mice.Experiments were performed in 15 male wild-type (BL10) and 15 male mdx mice at 4 months of age. Ventilation was assessed using whole-body plethysmography. Baseline measures of ventilation and metabolism were established. Mice were exposed to 10 successive bouts of hypoxia, each lasting 5 min, interspersed with 5-min bouts of normoxia. Measurements were taken for 60 min following termination of AIH.In mdx mice, ventilation was significantly increased 60 min post-AIH compared to baseline. However, metabolic CO2 production was also increased. Therefore, ventilatory equivalent was unaffected by AIH exposure, i.e., no ventilatory LTF manifestation. In wild-type mice, ventilation and metabolism were not affected by AIH.Eliciting ventilatory LTF is dependent on many factors and may require concomitant isocapnia or hypercapnia during AIH exposures and/or repeated daily AIH exposures, which is worthy of further pursuit.
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Affiliation(s)
- Michael N Maxwell
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Anthony L Marullo
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Aoife D Slyne
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Eric F Lucking
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Ken D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland.
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6
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Yoo HS, Shanmugalingam U, Smith PD. Potential roles of branched-chain amino acids in neurodegeneration. Nutrition 2022; 103-104:111762. [DOI: 10.1016/j.nut.2022.111762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 03/12/2022] [Accepted: 05/31/2022] [Indexed: 10/31/2022]
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7
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Finn HT, Bogdanovski O, Hudson AL, McCaughey EJ, Crawford MR, Taylor JL, Butler JE, Gandevia SC. The effect of acute intermittent hypoxia on human limb motoneurone output. Exp Physiol 2022; 107:615-630. [PMID: 35338753 DOI: 10.1113/ep090099] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 03/17/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does a single session of repeated bouts of acute intermittent hypoxic breathing enhance the motoneuronal output of the limb muscles of healthy able-bodied participants? What is the main finding and its importance? Compared to breathing room air, there were some increases in motoneuronal output following acute intermittent hypoxia, but the increases were variable across participants, in time after the intervention and depended on which neurophysiological measure was checked. ABSTRACT Acute intermittent hypoxia (AIH) induces persistent increases in output from rat phrenic motoneurones. Studies in people with spinal cord injury suggest AIH improves limb performance, perhaps via postsynaptic changes at cortico-motoneuronal synapses. We assessed whether limb motoneurone output in response to reflex and descending synaptic activation is facilitated after one session of AIH in healthy able-bodied volunteers. Fourteen participants completed two experimental days, either AIH or a sham intervention (randomised crossover design). We measured H-reflex recruitment curves and homosynaptic post-activation depression (HPAD) of the H reflex in soleus, and motor evoked potentials (MEPs) evoked by transcranial magnetic stimulation (TMS) and their recruitment curves, in first dorsal interosseous. All measurements were performed at rest and occurred at baseline, 0, 20, 40, and 60 minutes post-intervention. The intervention was 30 minutes of either normoxia (sham, FiO2 ≈ 0.21) or AIH (alternate 1-minute hypoxia [FiO2 ≈ 0.09], 1-minute normoxia). After AIH the H-reflex recruitment curve shifted leftward. Lower stimulation intensities were needed to evoke 5%, 50%, and 99% of the maximal H reflex at 40 and 60 minutes after AIH (P<0.04). The maximal H reflex, recruitment slope and HPAD, were unchanged after AIH. MEPs evoked by constant intensity TMS were larger 40 minutes after AIH (P = 0.027). There was no change in MEP recruitment or the maximal MEP. In conclusion, some measures of the evoked responses from limb motoneurones increased after a single AIH session, but only at discrete time points. It is unclear to what extent these changes alter functional performance. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Harrison T Finn
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
| | - Oliver Bogdanovski
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
| | - Anna L Hudson
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia.,College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, 5042, Australia
| | - Euan J McCaughey
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
| | | | - Janet L Taylor
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,Edith Cowan University, Perth, WA, 6027, Australia
| | - Jane E Butler
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
| | - Simon C Gandevia
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
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8
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Sajjadi E, Seven YB, Ehrbar JG, Wymer JP, Mitchell GS, Smith BK. Acute intermittent hypoxia and respiratory muscle recruitment in people with amyotrophic lateral sclerosis: A preliminary study. Exp Neurol 2022; 347:113890. [PMID: 34624328 PMCID: PMC9488543 DOI: 10.1016/j.expneurol.2021.113890] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 09/28/2021] [Accepted: 10/03/2021] [Indexed: 01/03/2023]
Abstract
Respiratory failure is the main cause of death in amyotrophic lateral sclerosis (ALS). Since no effective treatments to preserve independent breathing are available, there is a critical need for new therapies to preserve or restore breathing ability. Since acute intermittent hypoxia (AIH) elicits spinal respiratory motor plasticity in rodent ALS models, and may restore breathing ability in people with ALS, we performed a proof-of-principle study to investigate this possibility in ALS patients. Quiet breathing, sniff nasal inspiratory pressure (SNIP) and maximal inspiratory pressure (MIP) were tested in 13 persons with ALS and 10 age-matched controls, before and 60 min post-AIH (15, 1 min episodes of 10% O2, 2 min normoxic intervals) or sham AIH (continuous normoxia). The root mean square (RMS) of the right and left diaphragm, 2nd parasternal, scalene and sternocleidomastoid muscles were monitored. A vector analysis was used to calculate summated vector magnitude (Mag) and similarity index (SI) of collective EMG activity during quiet breathing, SNIP and MIP maneuvers. AIH facilitated tidal volume and minute ventilation (treatment main effects: p < 0.05), and Mag (ie. collective respiratory muscle activity; p < 0.001) during quiet breathing in ALS and control subjects, but there was no effect on SI during quiet breathing. SNIP SI decreased in both groups post-AIH (p < 0.005), whereas Mag was unchanged (p = 0.09). No differences were observed in SNIP or MIP post AIH in either group. Discomfort was not reported during AIH by any subject, nor were adverse events observed. Thus, AIH may be a safe way to increase collective inspiratory muscle activity during quiet breathing in ALS patients, although a single AIH presentation was not sufficient to significantly increase peak inspiratory pressure generation. These preliminary results provide evidence that AIH may improve breathing function in people with ALS, and that future studies of prolonged, repetitive AIH protocols are warranted.
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Affiliation(s)
- Elaheh Sajjadi
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA, 32610,McKnight Brain Institute, University of Florida, Gainesville, FL, USA, 32610,Department of Physical Therapy, University of Florida, Gainesville, FL, USA, 32610
| | - Yasin B. Seven
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA, 32610,McKnight Brain Institute, University of Florida, Gainesville, FL, USA, 32610,Department of Physical Therapy, University of Florida, Gainesville, FL, USA, 32610
| | - Jessica G Ehrbar
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA, 32610
| | - James P. Wymer
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA, 32610,McKnight Brain Institute, University of Florida, Gainesville, FL, USA, 32610,Neurology, University of Florida, Gainesville, FL, USA, 32610
| | - Gordon S. Mitchell
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA, 32610,McKnight Brain Institute, University of Florida, Gainesville, FL, USA, 32610,Department of Physical Therapy, University of Florida, Gainesville, FL, USA, 32610
| | - Barbara K. Smith
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA, 32610,Department of Physical Therapy, University of Florida, Gainesville, FL, USA, 32610,Pediatrics, University of Florida, Gainesville, FL, USA, 32610
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9
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Vose AK, Welch JF, Nair J, Dale EA, Fox EJ, Muir GD, Trumbower RD, Mitchell GS. Therapeutic acute intermittent hypoxia: A translational roadmap for spinal cord injury and neuromuscular disease. Exp Neurol 2022; 347:113891. [PMID: 34637802 PMCID: PMC8820239 DOI: 10.1016/j.expneurol.2021.113891] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/29/2021] [Accepted: 10/03/2021] [Indexed: 01/03/2023]
Abstract
We review progress towards greater mechanistic understanding and clinical translation of a strategy to improve respiratory and non-respiratory motor function in people with neuromuscular disorders, therapeutic acute intermittent hypoxia (tAIH). In 2016 and 2020, workshops to create and update a "road map to clinical translation" were held to help guide future research and development of tAIH to restore movement in people living with chronic, incomplete spinal cord injuries. After briefly discussing the pioneering, non-targeted basic research inspiring this novel therapeutic approach, we then summarize workshop recommendations, emphasizing critical knowledge gaps, priorities for future research effort, and steps needed to accelerate progress as we evaluate the potential of tAIH for routine clinical use. Highlighted areas include: 1) greater mechanistic understanding, particularly in non-respiratory motor systems; 2) optimization of tAIH protocols to maximize benefits; 3) identification of combinatorial treatments that amplify plasticity or remove plasticity constraints, including task-specific training; 4) identification of biomarkers for individuals most/least likely to benefit from tAIH; 5) assessment of long-term tAIH safety; and 6) development of a simple, safe and effective device to administer tAIH in clinical and home settings. Finally, we update ongoing clinical trials and recent investigations of tAIH in SCI and other clinical disorders that compromise motor function, including ALS, multiple sclerosis, and stroke.
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Affiliation(s)
- Alicia K Vose
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA; Brooks Rehabilitation, Jacksonville, FL 32216, USA
| | - Joseph F Welch
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA; Brooks Rehabilitation, Jacksonville, FL 32216, USA
| | - Jayakrishnan Nair
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Erica A Dale
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL 32610, USA
| | - Emily J Fox
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA; Brooks Rehabilitation, Jacksonville, FL 32216, USA
| | - Gillian D Muir
- Department of Biomedical Sciences, WCVM, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
| | - Randy D Trumbower
- Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, USA
| | - Gordon S Mitchell
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
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10
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Allen LL, Nichols NL, Asa ZA, Emery AT, Ciesla MC, Santiago JV, Holland AE, Mitchell GS, Gonzalez-Rothi EJ. Phrenic motor neuron survival below cervical spinal cord hemisection. Exp Neurol 2021; 346:113832. [PMID: 34363808 PMCID: PMC9065093 DOI: 10.1016/j.expneurol.2021.113832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 07/31/2021] [Accepted: 08/02/2021] [Indexed: 02/04/2023]
Abstract
Cervical spinal cord injury (cSCI) severs bulbospinal projections to respiratory motor neurons, paralyzing respiratory muscles below the injury. C2 spinal hemisection (C2Hx) is a model of cSCI often used to study spontaneous and induced plasticity and breathing recovery post-injury. One key assumption is that C2Hx dennervates motor neurons below the injury, but does not affect their survival. However, a recent study reported substantial bilateral motor neuron death caudal to C2Hx. Since phrenic motor neuron (PMN) death following C2Hx would have profound implications for therapeutic strategies designed to target spared neural circuits, we tested the hypothesis that C2Hx minimally impacts PMN survival. Using improved retrograde tracing methods, we observed no loss of PMNs at 2- or 8-weeks post-C2Hx. We also observed no injury-related differences in ChAT or NeuN immunolabeling within labelled PMNs. Although we found no evidence of PMN loss following C2Hx, we cannot rule out neuronal loss in other motor pools. These findings address an essential prerequisite for studies that utilize C2Hx as a model to explore strategies for inducing plasticity and/or regeneration within the phrenic motor system, as they provide important insights into the viability of phrenic motor neurons as therapeutic targets after high cervical injury.
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Affiliation(s)
- Latoya L Allen
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Nicole L Nichols
- Department of Biomedical Sciences and Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, USA
| | - Zachary A Asa
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | | | - Marissa C Ciesla
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Juliet V Santiago
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Ashley E Holland
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Gordon S Mitchell
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Elisa J Gonzalez-Rothi
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
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11
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How Are Adenosine and Adenosine A 2A Receptors Involved in the Pathophysiology of Amyotrophic Lateral Sclerosis? Biomedicines 2021; 9:biomedicines9081027. [PMID: 34440231 PMCID: PMC8392384 DOI: 10.3390/biomedicines9081027] [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: 07/13/2021] [Revised: 08/03/2021] [Accepted: 08/12/2021] [Indexed: 12/19/2022] Open
Abstract
Adenosine is extensively distributed in the central and peripheral nervous systems, where it plays a key role as a neuromodulator. It has long been implicated in the pathogenesis of progressive neurogenerative disorders such as Parkinson’s disease, and there is now growing interest in its role in amyotrophic lateral sclerosis (ALS). The motor neurons affected in ALS are responsive to adenosine receptor function, and there is accumulating evidence for beneficial effects of adenosine A2A receptor antagonism. In this article, we focus on recent evidence from ALS clinical pathology and animal models that support dynamism of the adenosinergic system (including changes in adenosine levels and receptor changes) in ALS. We review the possible mechanisms of chronic neurodegeneration via the adenosinergic system, potential biomarkers and the acute symptomatic pharmacology, including respiratory motor neuron control, of A2A receptor antagonism to explore the potential of the A2A receptor as target for ALS therapy.
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Borkowski LF, Smith CL, Keilholz AN, Nichols NL. Divergent receptor utilization is necessary for phrenic long-term facilitation over the course of motor neuron loss following CTB-SAP intrapleural injections. J Neurophysiol 2021; 126:709-722. [PMID: 34288779 DOI: 10.1152/jn.00236.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Intrapleural injection of cholera toxin B conjugated to saporin (CTB-SAP) mimics respiratory motor neuron death and respiratory deficits observed in rat models of neuromuscular diseases. Seven-day CTB-SAP rats elicit enhanced phrenic long-term facilitation (pLTF) primarily through TrkB and PI3K/Akt-dependent mechanisms [i.e., Gs-pathway, which can be initiated by adenosine 2A (A2A) receptors in naïve rats], whereas 28-day CTB-SAP rats elicit moderate pLTF though BDNF- and MEK-/ERK-dependent mechanisms [i.e., Gq-pathway, which is typically initiated by serotonin (5-HT) receptors in naïve rats]. Here, we tested the hypothesis that pLTF following CTB-SAP is 1) A2A receptor-dependent at 7 days and 2) 5-HT receptor-dependent at 28 days. Adult Sprague-Dawley male rats were anesthetized, paralyzed, ventilated, and exposed to acute intermittent hypoxia (AIH; 3-, 5-min bouts of 10.5% O2) following bilateral, intrapleural injections at 7 days and 28 days of 1) CTB-SAP (25 µg) or 2) unconjugated CTB and SAP (control). Intrathecal C4 delivery included either the 1) A2A receptor antagonist (MSX-3; 10 µM; 12 µL) or 2) 5-HT receptor antagonist (methysergide; 20 mM; 15 µL). pLTF was abolished with A2A receptor inhibition in 7-day, not 28-day, CTB-SAP rats versus controls (P < 0.05), whereas pLTF was abolished following 5-HT receptor inhibition in 28-day, not 7-day, CTB-SAP rats versus controls (P < 0.05). In addition, 5-HT2A receptor expression was unchanged in CTB-SAP rats versus controls, whereas 5-HT2B receptor expression was decreased in CTB-SAP rats versus controls (P < 0.05). This study furthers our understanding of the contribution of differential receptor activation to pLTF and its implications for breathing following respiratory motor neuron death.NEW & NOTEWORTHY The current study investigates underlying receptor-dependent mechanisms contributing to phrenic long-term facilitation (pLTF) following CTB-SAP-induced respiratory motor neuron death at 7 days and 28 days. We found that A2A receptors are required for enhanced pLTF in 7-day CTB-SAP rats, whereas 5-HT receptors are required for moderate pLTF in 28-day CTB-SAP rats. Targeting these time-dependent mechanisms have implications for breathing maintenance over the course of many neuromuscular diseases.
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Affiliation(s)
- Lauren F Borkowski
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Catherine L Smith
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Amy N Keilholz
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Nicole L Nichols
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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Borkowski LF, Nichols NL. Differential mechanisms are required for phrenic long-term facilitation over the course of motor neuron loss following CTB-SAP intrapleural injections. Exp Neurol 2020; 334:113460. [PMID: 32916172 PMCID: PMC10823911 DOI: 10.1016/j.expneurol.2020.113460] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/28/2020] [Accepted: 09/01/2020] [Indexed: 01/25/2023]
Abstract
Selective elimination of respiratory motor neurons using intrapleural injections of cholera toxin B fragment conjugated to saporin (CTB-SAP) mimics motor neuron death and respiratory deficits observed in rat models of neuromuscular diseases. This CTB-SAP model allows us to study the impact of motor neuron death on the output of surviving phrenic motor neurons. After 7(d) days of CTB-SAP, phrenic long-term facilitation (pLTF, a form of respiratory plasticity) is enhanced, but returns towards control levels at 28d. However, the mechanism responsible for this difference in magnitude of pLTF is unknown. In naïve rats, pLTF predominately requires 5-HT2 receptors, the new synthesis of BDNF, and MEK/ERK signaling; however, pLTF can alternatively be induced via A2A receptors, the new synthesis of TrkB, and PI3K/Akt signaling. Since A2A receptor-dependent pLTF is enhanced in naïve rats, we suggest that 7d CTB-SAP treated rats utilize the alternative mechanism for pLTF. Here, we tested the hypothesis that pLTF following CTB-SAP is: 1) TrkB and PI3K/Akt, not BDNF and MEK/ERK, dependent at 7d; and 2) BDNF and MEK/ERK, not TrkB and PI3K/Akt, dependent at 28d. Adult Sprague Dawley male rats were anesthetized, paralyzed, ventilated, and were exposed to acute intermittent hypoxia (AIH; 3, 5 min bouts of 10.5% O2) following bilateral, intrapleural injections at 7d and 28d of: 1) CTB-SAP (25 μg), or 2) un-conjugated CTB and SAP (control). Intrathecal C4 delivery included either: 1) small interfering RNA that targeted BDNF or TrkB mRNA; 2) UO126 (MEK/ERK inhibitor); or 3) PI828 (PI3K/Akt inhibitor). Our data suggest that pLTF in 7d CTB-SAP treated rats is elicited primarily through TrkB and PI3K/Akt-dependent mechanisms, whereas BDNF and MEK/ERK-dependent mechanisms induce pLTF in 28d CTB-SAP treated rats. This project increases our understanding of respiratory plasticity and its implications for breathing following motor neuron death.
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Affiliation(s)
- Lauren F Borkowski
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, United States of America
| | - Nicole L Nichols
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, United States of America.
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Miranda-Lourenço C, Ribeiro-Rodrigues L, Fonseca-Gomes J, Tanqueiro SR, Belo RF, Ferreira CB, Rei N, Ferreira-Manso M, de Almeida-Borlido C, Costa-Coelho T, Freitas CF, Zavalko S, Mouro FM, Sebastião AM, Xapelli S, Rodrigues TM, Diógenes MJ. Challenges of BDNF-based therapies: From common to rare diseases. Pharmacol Res 2020; 162:105281. [PMID: 33161136 DOI: 10.1016/j.phrs.2020.105281] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 12/11/2022]
Abstract
Neurotrophins are a well-known family of neurotrophic factors that play an important role both in the central and peripheral nervous systems, where they modulate neuronal survival, development, function and plasticity. Brain-derived neurotrophic factor (BDNF) possesses diverse biological functions which are mediated by the activation of two main classes of receptors, the tropomyosin-related kinase (Trk) B and the p75 neurotrophin receptor (p75NTR). The therapeutic potential of BDNF has drawn attention since dysregulation of its signalling cascades has been suggested to underlie the pathogenesis of both common and rare diseases. Multiple strategies targeting this neurotrophin have been tested; most have found obstacles that ultimately hampered their effectiveness. This review focuses on the involvement of BDNF and its receptors in the pathophysiology of Alzheimer's disease (AD), Amyotrophic Lateral Sclerosis (ALS) and Rett Syndrome (RTT). We describe the known mechanisms leading to the impairment of BDNF/TrkB signalling in these disorders. Such mechanistic insight highlights how BDNF signalling compromise can take various shapes, nearly disease-specific. Therefore, BDNF-based therapeutic strategies must be specifically tailored and are more likely to succeed if a combination of resources is employed.
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Affiliation(s)
- Catarina Miranda-Lourenço
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Leonor Ribeiro-Rodrigues
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - João Fonseca-Gomes
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Sara R Tanqueiro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Rita F Belo
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Catarina B Ferreira
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Nádia Rei
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Mafalda Ferreira-Manso
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Carolina de Almeida-Borlido
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Tiago Costa-Coelho
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Céline Felicidade Freitas
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Svitlana Zavalko
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Francisco M Mouro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Ana M Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Sara Xapelli
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Tiago M Rodrigues
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Institute of Molecular and Clinical Ophthalmology Basel (IOB), Mittlere Strasse 91, 4031 Basel, Switzerland
| | - Maria J Diógenes
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, 1649-028 Lisboa, Portugal.
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Borkowski LF, Craig TA, Stricklin OE, Johnson KA, Nichols NL. 5-HT2A/B receptor expression in the phrenic motor nucleus in a rat model of ALS (SOD1 G93A). Respir Physiol Neurobiol 2020; 279:103471. [PMID: 32504811 PMCID: PMC7384973 DOI: 10.1016/j.resp.2020.103471] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/23/2020] [Accepted: 05/27/2020] [Indexed: 12/13/2022]
Abstract
Despite respiratory motor neuron death, ventilation is preserved in SOD1G93A rats. Compensatory respiratory plasticity may counterbalance the loss of these neurons. Phrenic long-term facilitation (pLTF; a form of respiratory plasticity) in naïve rats is 5-HT2 and NADPH oxidase-dependent. Furthermore, 5-HT2A, not 5-HT2B, receptor-induced phrenic motor facilitation is NADPH oxidase-independent in naïve rats. pLTF is NADPH oxidase-dependent in pre-symptomatic, but not end-stage, SOD1G93A rats. Here, we hypothesized that in the putative phrenic motor nucleus (PMN) of SOD1G93A rats vs. wild-type littermates: 1) pre-symptomatic rats would have greater 5-HT2B receptor expression that decreases at end-stage; and 2) 5-HT2A receptor expression would increase from pre-symptomatic to end-stage. Putative PMN 5-HT2A receptor expression was reduced when comparing across (but not within) pre-symptomatic vs. end-stage groups (p < 0.05). In contrast, putative PMN 5-HT2B receptor expression was increased when comparing across pre-symptomatic vs. end-stage groups, and within end-stage groups (p < 0.05). These data suggest a potential role for 5-HT2 receptors in pLTF and breathing in SOD1G93A rats.
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Affiliation(s)
- Lauren F Borkowski
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, United States
| | - Taylor A Craig
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, United States
| | - Olivia E Stricklin
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, United States
| | - Katherine A Johnson
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, United States
| | - Nicole L Nichols
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, United States.
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The Impact of Kinases in Amyotrophic Lateral Sclerosis at the Neuromuscular Synapse: Insights into BDNF/TrkB and PKC Signaling. Cells 2019; 8:cells8121578. [PMID: 31817487 PMCID: PMC6953086 DOI: 10.3390/cells8121578] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 11/19/2019] [Accepted: 12/03/2019] [Indexed: 12/14/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) promotes neuron survival in adulthood in the central nervous system. In the peripheral nervous system, BDNF is a contraction-inducible protein that, through its binding to tropomyosin-related kinase B receptor (TrkB), contributes to the retrograde neuroprotective control done by muscles, which is necessary for motor neuron function. BDNF/TrkB triggers downstream presynaptic pathways, involving protein kinase C, essential for synaptic function and maintenance. Undeniably, this reciprocally regulated system exemplifies the tight communication between nerve terminals and myocytes to promote synaptic function and reveals a new view about the complementary and essential role of pre and postsynaptic interplay in keeping the synapse healthy and strong. This signaling at the neuromuscular junction (NMJ) could establish new intervention targets across neuromuscular diseases characterized by deficits in presynaptic activity and muscle contractility and by the interruption of the connection between nervous and muscular tissues, such as amyotrophic lateral sclerosis (ALS). Indeed, exercise and other therapies that modulate kinases are effective at delaying ALS progression, preserving NMJs and maintaining motor function to increase the life quality of patients. Altogether, we review synaptic activity modulation of the BDNF/TrkB/PKC signaling to sustain NMJ function, its and other kinases’ disturbances in ALS and physical and molecular mechanisms to delay disease progression.
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Pradhan J, Noakes PG, Bellingham MC. The Role of Altered BDNF/TrkB Signaling in Amyotrophic Lateral Sclerosis. Front Cell Neurosci 2019; 13:368. [PMID: 31456666 PMCID: PMC6700252 DOI: 10.3389/fncel.2019.00368] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 07/29/2019] [Indexed: 12/11/2022] Open
Abstract
Brain derived neurotrophic factor (BDNF) is well recognized for its neuroprotective functions, via activation of its high affinity receptor, tropomysin related kinase B (TrkB). In addition, BDNF/TrkB neuroprotective functions can also be elicited indirectly via activation of adenosine 2A receptors (A2aRs), which in turn transactivates TrkB. Evidence suggests that alterations in BDNF/TrkB, including TrkB transactivation by A2aRs, can occur in several neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). Although enhancing BDNF has been a major goal for protection of dying motor neurons (MNs), this has not been successful. Indeed, there is emerging in vitro and in vivo evidence suggesting that an upregulation of BDNF/TrkB can cause detrimental effects on MNs, making them more vulnerable to pathophysiological insults. For example, in ALS, early synaptic hyper-excitability of MNs is thought to enhance BDNF-mediated signaling, thereby causing glutamate excitotoxicity, and ultimately MN death. Moreover, direct inhibition of TrkB and A2aRs has been shown to protect MNs from these pathophysiological insults, suggesting that modulation of BDNF/TrkB and/or A2aRs receptors may be important in early disease pathogenesis in ALS. This review highlights the relevance of pathophysiological actions of BDNF/TrkB under certain circumstances, so that manipulation of BDNF/TrkB and A2aRs may give rise to alternate neuroprotective therapeutic strategies in the treatment of neural diseases such as ALS.
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Affiliation(s)
- Jonu Pradhan
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Peter G Noakes
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Mark C Bellingham
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
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Seven YB, Mitchell GS. Mechanisms of compensatory plasticity for respiratory motor neuron death. Respir Physiol Neurobiol 2019; 265:32-39. [PMID: 30625378 DOI: 10.1016/j.resp.2019.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 12/22/2018] [Accepted: 01/03/2019] [Indexed: 02/06/2023]
Abstract
Respiratory motor neuron death arises from multiple neurodegenerative and traumatic neuromuscular disorders. Despite motor neuron death, compensatory mechanisms minimize its functional impact by harnessing intrinsic mechanisms of compensatory respiratory plasticity. However, the capacity for compensation eventually reaches limits and pathology ensues. Initially, challenges to the system such as increased metabolic demand reveal sub-clinical pathology. With greater motor neuron loss, the eventual result is de-compensation, ventilatory failure, ventilator dependence and then death. In this brief review, we discuss recent advances in our understanding of mechanisms giving rise to compensatory respiratory plasticity in response to respiratory motor neuron death including: 1) increased central respiratory drive, 2) plasticity in synapses on spared phrenic motor neurons, 3) enhanced neuromuscular transmission and 4) shifts in respiratory muscle utilization from more affected to less affected motor pools. Some of these compensatory mechanisms may prolong breathing function, but hasten the demise of surviving motor neurons. Improved understanding of these mechanisms and their impact on survival of spared motor neurons will guide future efforts to develop therapeutic interventions that preserve respiratory function with neuromuscular injury/disease.
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Affiliation(s)
- Yasin B Seven
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA
| | - Gordon S Mitchell
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA.
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Nichols NL, Craig TA, Tanner MA. Phrenic long-term facilitation following intrapleural CTB-SAP-induced respiratory motor neuron death. Respir Physiol Neurobiol 2017; 256:43-49. [PMID: 28822818 DOI: 10.1016/j.resp.2017.08.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/20/2017] [Accepted: 08/04/2017] [Indexed: 01/26/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating disease leading to progressive motor neuron degeneration and death by ventilatory failure. In a rat model of ALS (SOD1G93A), phrenic long-term facilitation (pLTF) following acute intermittent hypoxia (AIH) is enhanced greater than expected at disease end-stage but the mechanism is unknown. We suggest that one trigger for this enhancement is motor neuron death itself. Intrapleural injections of cholera toxin B fragment conjugated to saporin (CTB-SAP) selectively kill respiratory motor neurons and mimic motor neuron death observed in SOD1G93A rats. This CTB-SAP model allows us to study the impact of respiratory motor neuron death on breathing without many complications attendant to ALS. Here, we tested the hypothesis that phrenic motor neuron death is sufficient to enhance pLTF. pLTF was assessed in anesthetized, paralyzed and ventilated Sprague Dawley rats 7 and 28 days following bilateral intrapleural injections of: 1) CTB-SAP (25 μg), or 2) un-conjugated CTB and SAP (control). CTB-SAP enhanced pLTF at 7 (CTB-SAP: 162 ± 18%, n = 8 vs. Control: 63 ± 3%; n = 8; p < 0.05), but not 28 days post-injection (CTB-SAP: 64 ± 10%, n = 10 vs. Control: 60 ± 13; n = 8; p > 0.05). Thus, pLTF at 7 (not 28) days post-CTB-SAP closely resembles pLTF in end-stage ALS rats, suggesting that processes unique to the early period of motor neuron death enhance pLTF. This project increases our understanding of respiratory plasticity and its implications for breathing in motor neuron disease.
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Affiliation(s)
- Nicole L Nichols
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, 65211, United States.
| | - Taylor A Craig
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, 65211, United States
| | - Miles A Tanner
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, 65211, United States
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