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Habecker BA, Bers DM, Birren SJ, Chang R, Herring N, Kay MW, Li D, Mendelowitz D, Mongillo M, Montgomery JM, Ripplinger CM, Tampakakis E, Winbo A, Zaglia T, Zeltner N, Paterson DJ. Molecular and cellular neurocardiology in heart disease. J Physiol 2024. [PMID: 38778747 DOI: 10.1113/jp284739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 04/16/2024] [Indexed: 05/25/2024] Open
Abstract
This paper updates and builds on a previous White Paper in this journal that some of us contributed to concerning the molecular and cellular basis of cardiac neurobiology of heart disease. Here we focus on recent findings that underpin cardiac autonomic development, novel intracellular pathways and neuroplasticity. Throughout we highlight unanswered questions and areas of controversy. Whilst some neurochemical pathways are already demonstrating prognostic viability in patients with heart failure, we also discuss the opportunity to better understand sympathetic impairment by using patient specific stem cells that provides pathophysiological contextualization to study 'disease in a dish'. Novel imaging techniques and spatial transcriptomics are also facilitating a road map for target discovery of molecular pathways that may form a therapeutic opportunity to treat cardiac dysautonomia.
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Affiliation(s)
- Beth A Habecker
- Department of Chemical Physiology & Biochemistry, Department of Medicine Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis School of Medicine, Davis, CA, USA
| | - Susan J Birren
- Department of Biology, Volen Center for Complex Systems, Brandeis University, Waltham, MA, USA
| | - Rui Chang
- Department of Neuroscience, Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Neil Herring
- Burdon Sanderson Cardiac Science Centre and BHF Centre of Research Excellence, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Matthew W Kay
- Department of Biomedical Engineering, George Washington University, Washington, DC, USA
| | - Dan Li
- Burdon Sanderson Cardiac Science Centre and BHF Centre of Research Excellence, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - David Mendelowitz
- Department of Pharmacology and Physiology, George Washington University, Washington, DC, USA
| | - Marco Mongillo
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Johanna M Montgomery
- Department of Physiology and Manaaki Manawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Crystal M Ripplinger
- Department of Pharmacology, University of California, Davis School of Medicine, Davis, CA, USA
| | | | - Annika Winbo
- Department of Physiology and Manaaki Manawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Tania Zaglia
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Nadja Zeltner
- Departments of Biochemistry and Molecular Biology, Cell Biology, and Center for Molecular Medicine, University of Georgia, Athens, GA, USA
| | - David J Paterson
- Burdon Sanderson Cardiac Science Centre and BHF Centre of Research Excellence, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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Ashton JL, Prince B, Sands G, Argent L, Anderson M, Smith JEG, Tedoldi A, Ahmad A, Baddeley D, Pereira AG, Lever N, Ramanathan T, Smaill BH, Montgomery JM. Electrophysiology and 3D-imaging reveal properties of human intracardiac neurons and increased excitability with atrial fibrillation. J Physiol 2024. [PMID: 38687681 DOI: 10.1113/jp286278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 03/22/2024] [Indexed: 05/02/2024] Open
Abstract
Altered autonomic input to the heart plays a major role in atrial fibrillation (AF). Autonomic neurons termed ganglionated plexi (GP) are clustered on the heart surface to provide the last point of neural control of cardiac function. To date the properties of GP neurons in humans are unknown. Here we have addressed this knowledge gap in human GP neuron structure and physiology in patients with and without AF. Human right atrial GP neurons embedded in epicardial adipose tissue were excised during open heart surgery performed on both non-AF and AF patients and then characterised physiologically by whole cell patch clamp techniques. Structural analysis was also performed after fixation at both the single cell and at the entire GP levels via three-dimensional confocal imaging. Human GP neurons were found to exhibit unique properties and structural complexity with branched neurite outgrowth. Significant differences in excitability were revealed between AF and non-AF GP neurons as measured by lower current to induce action potential firing, a reduced occurrence of low action potential firing rates, decreased accommodation and increased synaptic density. Visualisation of entire GPs showed almost all neurons are cholinergic with a small proportion of noradrenergic and dual phenotype neurons. Phenotypic distribution differences occurred with AF including decreased cholinergic and dual phenotype neurons, and increased noradrenergic neurons. These data show both functional and structural differences occur between GP neurons from patients with and without AF, highlighting that cellular plasticity occurs in neural input to the heart that could alter autonomic influence on atrial function. KEY POINTS: The autonomic nervous system plays a critical role in regulating heart rhythm and the initiation of AF; however, the structural and functional properties of human autonomic neurons in the autonomic ganglionated plexi (GP) remain unknown. Here we perform the first whole cell patch clamp electrophysiological and large tissue confocal imaging analysis of these neurons from patients with and without AF. Our data show human GP neurons are functionally and structurally complex. Measurements of action potential kinetics show higher excitability in GP neurons from AF patients as measured by lower current to induce action potential firing, reduced low firing action potential rates, and decreased action potential accommodation. Confocal imaging shows increased synaptic density and noradrenergic phenotypes in patients with AF. Both functional and structural differences occur in GP neurons from patients with AF that could alter autonomic influence on atrial rhythm.
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Affiliation(s)
- J L Ashton
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Manaaki Manawa Centre for Heart Research, University of Auckland and Pūtahi Manawa Centre of Research Excellence, Auckland, New Zealand
| | - B Prince
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Manaaki Manawa Centre for Heart Research, University of Auckland and Pūtahi Manawa Centre of Research Excellence, Auckland, New Zealand
| | - G Sands
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - L Argent
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Manaaki Manawa Centre for Heart Research, University of Auckland and Pūtahi Manawa Centre of Research Excellence, Auckland, New Zealand
| | - M Anderson
- Cardiothoracic Surgical Unit, Auckland City Hospital, Auckland, New Zealand
| | - J E G Smith
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Manaaki Manawa Centre for Heart Research, University of Auckland and Pūtahi Manawa Centre of Research Excellence, Auckland, New Zealand
| | - A Tedoldi
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Manaaki Manawa Centre for Heart Research, University of Auckland and Pūtahi Manawa Centre of Research Excellence, Auckland, New Zealand
| | - A Ahmad
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Manaaki Manawa Centre for Heart Research, University of Auckland and Pūtahi Manawa Centre of Research Excellence, Auckland, New Zealand
| | - D Baddeley
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - A G Pereira
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - N Lever
- Manaaki Manawa Centre for Heart Research, University of Auckland and Pūtahi Manawa Centre of Research Excellence, Auckland, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
- Department of Cardiology, Auckland City Hospital, Auckland, New Zealand
| | - T Ramanathan
- Manaaki Manawa Centre for Heart Research, University of Auckland and Pūtahi Manawa Centre of Research Excellence, Auckland, New Zealand
- Cardiothoracic Surgical Unit, Auckland City Hospital, Auckland, New Zealand
| | - B H Smaill
- Manaaki Manawa Centre for Heart Research, University of Auckland and Pūtahi Manawa Centre of Research Excellence, Auckland, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Manaaki Manawa Centre for Heart Research, University of Auckland and Pūtahi Manawa Centre of Research Excellence, Auckland, New Zealand
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Smith JEG, Ashton JL, Argent LP, Cheyne JE, Montgomery JM. Recording plasticity in neuronal activity in the rodent intrinsic cardiac nervous system using calcium imaging techniques. Front Synaptic Neurosci 2023; 15:1104736. [PMID: 37082542 PMCID: PMC10110955 DOI: 10.3389/fnsyn.2023.1104736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 03/20/2023] [Indexed: 04/22/2023] Open
Abstract
The intrinsic cardiac nervous system (ICNS) is composed of interconnected clusters of neurons called ganglionated plexi (GP) which play a major role in controlling heart rate and rhythm. The function of these neurons is particularly important due to their involvement in cardiac arrhythmias such as atrial fibrillation (AF), and previous work has shown that plasticity in GP neural networks could underpin aberrant activity patterns that drive AF. As research in this field increases, developing new techniques to visualize the complex interactions and plasticity in this GP network is essential. In this study we have developed a calcium imaging method enabling the simultaneous recording of plasticity in neuronal activity from multiple neurons in intact atrial GP networks. Calcium imaging was performed with Cal-520 AM labeling in aged spontaneously hypertensive rats (SHRs), which display both spontaneous and induced AF, and age-matched Wistar Kyoto (WKY) controls to determine the relationship between chronic hypertension, arrhythmia and GP calcium dynamics. Our data show that SHR GPs have significantly larger calcium responses to cholinergic stimulation compared to WKY controls, as determined by both higher amplitude and longer duration calcium responses. Responses were significantly but not fully blocked by hexamethonium, indicating multiple cholinergic receptor subtypes are involved in the calcium response. Given that SHRs are susceptible to cardiac arrhythmias, our data provide evidence for a potential link between arrhythmia and plasticity in calcium dynamics that occur not only in cardiomyocytes but also in the GP neurons of the heart.
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Affiliation(s)
- Joscelin E. G. Smith
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Pūtahi Manawa, Centre for Heart Research, Auckland, New Zealand
| | - Jesse L. Ashton
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Pūtahi Manawa, Centre for Heart Research, Auckland, New Zealand
| | - Liam P. Argent
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Pūtahi Manawa, Centre for Heart Research, Auckland, New Zealand
| | | | - Johanna M. Montgomery
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Pūtahi Manawa, Centre for Heart Research, Auckland, New Zealand
- *Correspondence: Johanna M. Montgomery,
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Lee K, Mills Z, Cheung P, Cheyne JE, Montgomery JM. The Role of Zinc and NMDA Receptors in Autism Spectrum Disorders. Pharmaceuticals (Basel) 2022; 16:ph16010001. [PMID: 36678498 PMCID: PMC9866730 DOI: 10.3390/ph16010001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
NMDA-type glutamate receptors are critical for synaptic plasticity in the central nervous system. Their unique properties and age-dependent arrangement of subunit types underpin their role as a coincidence detector of pre- and postsynaptic activity during brain development and maturation. NMDAR function is highly modulated by zinc, which is co-released with glutamate and concentrates in postsynaptic spines. Both NMDARs and zinc have been strongly linked to autism spectrum disorders (ASDs), suggesting that NMDARs are an important player in the beneficial effects observed with zinc in both animal models and children with ASDs. Significant evidence is emerging that these beneficial effects occur via zinc-dependent regulation of SHANK proteins, which form the backbone of the postsynaptic density. For example, dietary zinc supplementation enhances SHANK2 or SHANK3 synaptic recruitment and rescues NMDAR deficits and hypofunction in Shank3ex13-16-/- and Tbr1+/- ASD mice. Across multiple studies, synaptic changes occur in parallel with a reversal of ASD-associated behaviours, highlighting the zinc-dependent regulation of NMDARs and glutamatergic synapses as therapeutic targets for severe forms of ASDs, either pre- or postnatally. The data from rodent models set a strong foundation for future translational studies in human cells and people affected by ASDs.
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Khwaounjoo P, Sands GB, LeGrice IJ, Ramulgun G, Ashton JL, Montgomery JM, Gillis AM, Smaill BH, Trew ML. Multimodal imaging shows fibrosis architecture and action potential dispersion are predictors of arrhythmic risk in spontaneous hypertensive rats. J Physiol 2022; 600:4119-4135. [PMID: 35984854 PMCID: PMC9544618 DOI: 10.1113/jp282526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 08/08/2022] [Indexed: 11/08/2022] Open
Abstract
Hypertensive heart disease (HHD) increases risk of ventricular tachycardia (VT) and ventricular fibrillation (VF). The roles of structural vs. electrophysiological remodelling and age vs. disease progression are not fully understood. This cross-sectional study of cardiac alterations through HHD investigates mechanistic contributions to VT/VF risk. Risk was electrically assessed in Langendorff-perfused, spontaneously hypertensive rat hearts at 6, 12 and 18 months, and paced optical membrane voltage maps were acquired from the left ventricular (LV) free wall epicardium. Distributions of LV patchy fibrosis and 3D cellular architecture in representative anterior LV mid-wall regions were quantified from macroscopic and microscopic fluorescence images of optically cleared tissue. Imaging showed increased fibrosis from 6 months, particularly in the inner LV free wall. Myocyte cross-section increased at 12 months, while inter-myocyte connections reduced markedly with fibrosis. Conduction velocity decreased from 12 months, especially transverse to the myofibre direction, with rate-dependent anisotropy at 12 and 18 months, but not earlier. Action potential duration (APD) increased when clustered by age, as did APD dispersion at 12 and 18 months. Among 10 structural, functional and age variables, the most reliably linked were VT/VF risk, general LV fibrosis, a measure quantifying patchy fibrosis, and non-age clustered APD dispersion. VT/VF risk related to a quantified measure of patchy fibrosis, but age did not factor strongly. The findings are consistent with the notion that VT/VF risk is associated with rate-dependent repolarization heterogeneity caused by structural remodelling and reduced lateral electrical coupling between LV myocytes, providing a substrate for heterogeneous intramural activation as HHD progresses. KEY POINTS: There is heightened arrhythmic risk with progression of hypertensive heart disease. Risk is related to increasing left ventricular fibrosis, but the nature of this relationship has not been quantified. This study is a novel systematic characterization of changes in active electrical properties and fibrotic remodelling during progression of hypertensive heart disease in a well-established animal disease model. Arrhythmic risk is predicted by several left ventricular measures, in particular fibrosis quantity and structure, and epicardial action potential duration dispersion. Age alone is not a good predictor of risk. An improved understanding of links between arrhythmic risk and fibrotic architectures in progressive hypertensive heart disease aids better interpretation of late gadolinium-enhanced cardiac magnetic resonance imaging and electrical mapping signals.
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Affiliation(s)
| | - Gregory B. Sands
- Auckland Bioengineering InstituteUniversity of AucklandAucklandNew Zealand
| | - Ian J. LeGrice
- Auckland Bioengineering InstituteUniversity of AucklandAucklandNew Zealand,Department of PhysiologyUniversity of AucklandAucklandNew Zealand
| | - Girish Ramulgun
- Auckland Bioengineering InstituteUniversity of AucklandAucklandNew Zealand,IHU‐LirycUniversity of BordeauxBordeauxFrance
| | - Jesse L. Ashton
- Auckland Bioengineering InstituteUniversity of AucklandAucklandNew Zealand,Department of PhysiologyUniversity of AucklandAucklandNew Zealand
| | | | - Anne M. Gillis
- Libin Cardiovascular Institute of AlbertaUniversity of CalgaryCalgaryAlbertaCanada
| | - Bruce H. Smaill
- Auckland Bioengineering InstituteUniversity of AucklandAucklandNew Zealand
| | - Mark L. Trew
- Auckland Bioengineering InstituteUniversity of AucklandAucklandNew Zealand
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6
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Wilde M, Constantin L, Thorne PR, Montgomery JM, Scott EK, Cheyne JE. Auditory processing in rodent models of autism: a systematic review. J Neurodev Disord 2022; 14:48. [PMID: 36042393 PMCID: PMC9429780 DOI: 10.1186/s11689-022-09458-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 08/07/2022] [Indexed: 11/19/2022] Open
Abstract
Autism is a complex condition with many traits, including differences in auditory sensitivity. Studies in human autism are plagued by the difficulty of controlling for aetiology, whereas studies in individual rodent models cannot represent the full spectrum of human autism. This systematic review compares results in auditory studies across a wide range of established rodent models of autism to mimic the wide range of aetiologies in the human population. A search was conducted in the PubMed and Web of Science databases to find primary research articles in mouse or rat models of autism which investigate central auditory processing. A total of 88 studies were included. These used non-invasive measures of auditory function, such as auditory brainstem response recordings, cortical event-related potentials, electroencephalography, and behavioural tests, which are translatable to human studies. They also included invasive measures, such as electrophysiology and histology, which shed insight on the origins of the phenotypes found in the non-invasive studies. The most consistent results across these studies were increased latency of the N1 peak of event-related potentials, decreased power and coherence of gamma activity in the auditory cortex, and increased auditory startle responses to high sound levels. Invasive studies indicated loss of subcortical inhibitory neurons, hyperactivity in the lateral superior olive and auditory thalamus, and reduced specificity of responses in the auditory cortex. This review compares the auditory phenotypes across rodent models and highlights those that mimic findings in human studies, providing a framework and avenues for future studies to inform understanding of the auditory system in autism.
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Affiliation(s)
- Maya Wilde
- The Queensland Brain Institute, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Lena Constantin
- The Queensland Brain Institute, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Peter R Thorne
- Department of Physiology, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand.,Section of Audiology, School of Population Health, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Ethan K Scott
- The Queensland Brain Institute, The University of Queensland, Brisbane, QLD, 4072, Australia.,Department of Anatomy and Physiology, School of Biomedical Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Juliette E Cheyne
- Department of Physiology, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand.
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Lee K, Jung Y, Vyas Y, Skelton I, Abraham WC, Hsueh YP, Montgomery JM. Dietary zinc supplementation rescues fear-based learning and synaptic function in the Tbr1 +/- mouse model of autism spectrum disorders. Mol Autism 2022; 13:13. [PMID: 35303947 PMCID: PMC8932001 DOI: 10.1186/s13229-022-00494-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 03/07/2022] [Indexed: 12/02/2022] Open
Abstract
Background Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterised by a dyad of behavioural symptoms—social and communication deficits and repetitive behaviours. Multiple aetiological genetic and environmental factors have been identified as causing or increasing the likelihood of ASD, including serum zinc deficiency. Our previous studies revealed that dietary zinc supplementation can normalise impaired social behaviours, excessive grooming, and heightened anxiety in a Shank3 mouse model of ASD, as well as the amelioration of synapse dysfunction. Here, we have examined the efficacy and breadth of dietary zinc supplementation as an effective therapeutic strategy utilising a non-Shank-related mouse model of ASD—mice with Tbr1 haploinsufficiency. Methods We performed behavioural assays, amygdalar slice whole-cell patch-clamp electrophysiology, and immunohistochemistry to characterise the synaptic mechanisms underlying the ASD-associated behavioural deficits observed in Tbr1+/− mice and the therapeutic potential of dietary zinc supplementation. Two-way analysis of variance (ANOVA) with Šídák's post hoc test and one-way ANOVA with Tukey’s post hoc multiple comparisons were performed for statistical analysis. Results Our data show that dietary zinc supplementation prevents impairments in auditory fear memory and social interaction, but not social novelty, in the Tbr1+/− mice. Tbr1 haploinsufficiency did not induce excessive grooming nor elevate anxiety in mice. At the synaptic level, dietary zinc supplementation reversed α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) and N-methyl-d-aspartate receptor (NMDAR) hypofunction and normalised presynaptic function at thalamic-lateral amygdala (LA) synapses that are crucial for auditory fear memory. In addition, the zinc supplemented diet significantly restored the synaptic puncta density of the GluN1 subunit essential for functional NMDARs as well as SHANK3 expression in both the basal and lateral amygdala (BLA) of Tbr1+/− mice. Limitations The therapeutic effect of dietary zinc supplementation observed in rodent models may not reproduce the same effects in human patients. The effect of dietary zinc supplementation on synaptic function in other brain structures affected by Tbr1 haploinsufficiency including olfactory bulb and anterior commissure will also need to be examined. Conclusions Our data further the understanding of the molecular mechanisms underlying the effect of dietary zinc supplementation and verify the efficacy and breadth of its application as a potential treatment strategy for ASD.
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Affiliation(s)
- Kevin Lee
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Yewon Jung
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Yukti Vyas
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand.,INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Imogen Skelton
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Wickliffe C Abraham
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Yi-Ping Hsueh
- Institute of Molecular Biology, Academia Sinica, 128, Section 2, Academia Rd., Taipei, 11529, Taiwan
| | - Johanna M Montgomery
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand.
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Vyas Y, Cheyne JE, Lee K, Jung Y, Cheung PY, Montgomery JM. Shankopathies in the Developing Brain in Autism Spectrum Disorders. Front Neurosci 2022; 15:775431. [PMID: 35002604 PMCID: PMC8727517 DOI: 10.3389/fnins.2021.775431] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/22/2021] [Indexed: 11/13/2022] Open
Abstract
The SHANK family of proteins play critical structural and functional roles in the postsynaptic density (PSD) at excitatory glutamatergic synapses. Through their multidomain structure they form a structural platform across the PSD for protein–protein interactions, as well as recruiting protein complexes to strengthen excitatory synaptic transmission. Mutations in SHANKs reflect their importance to synapse development and plasticity. This is evident in autism spectrum disorder (ASD), a neurodevelopmental disorder resulting in behavioural changes including repetitive behaviours, lack of sociability, sensory issues, learning, and language impairments. Human genetic studies have revealed ASD mutations commonly occur in SHANKs. Rodent models expressing these mutations display ASD behavioural impairments, and a subset of these deficits are rescued by reintroduction of Shank in adult animals, suggesting that lack of SHANK during key developmental periods can lead to permanent changes in the brain’s wiring. Here we explore the differences in synaptic function and plasticity from development onward in rodent Shank ASD models. To date the most explored brain regions, relate to the behavioural changes observed, e.g., the striatum, hippocampus, sensory, and prefrontal cortex. In addition, less-studied regions including the hypothalamus, cerebellum, and peripheral nervous system are also affected. Synaptic phenotypes include weakened but also strengthened synaptic function, with NMDA receptors commonly affected, as well as changes in the balance of excitation and inhibition especially in cortical brain circuits. The effects of shankopathies in activity-dependent brain wiring is an important target for therapeutic intervention. We therefore highlight areas of research consensus and identify remaining questions and challenges.
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Affiliation(s)
- Yukti Vyas
- Department of Physiology, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Juliette E Cheyne
- Department of Physiology, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Kevin Lee
- Department of Physiology, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand.,Department of Pharmacology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Yewon Jung
- Department of Physiology, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand.,Department of Pharmacology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Pang Ying Cheung
- Department of Physiology, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand
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9
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Park TIH, Waldvogel HJ, Montgomery JM, Mee EW, Bergin PS, Faull RLM, Dragunow M, Curtis MA. Identifying Neural Progenitor Cells in the Adult Human Brain. Methods Mol Biol 2022; 2389:125-154. [PMID: 34558008 DOI: 10.1007/978-1-0716-1783-0_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The discovery, in 1998, that the adult human brain contains at least two populations of progenitor cells and that progenitor cells are upregulated in response to a range of degenerative brain diseases has raised hopes for their use in replacing dying brain cells. Since these early findings, the race has been on to understand the biology of progenitor cells in the human brain, and they have now been isolated and studied in many major neurodegenerative diseases. Before these cells can be exploited for cell replacement purposes, it is important to understand how to (1) locate them, (2) label them, (3) determine what receptors they express, (4) isolate them, and (5) examine their electrophysiological properties when differentiated. In this chapter we have described the methods we use for studying progenitor cells in the adult human brain and in particular the tissue processing, immunohistochemistry, autoradiography, progenitor cell culture, and electrophysiology on brain cells. The Neurological Foundation of New Zealand Human Brain Bank has been receiving human tissue for approximately 25 years during which time we have developed a number of unique ways to examine and isolate progenitor cells from resected surgical specimens as well as from postmortem brain tissue. There are ethical and technical considerations that are unique to working with human brain tissue, and these, as well as the processing of this tissue and the culturing of it for the purpose of studying progenitor cells, are the topic of this chapter.
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Affiliation(s)
- Thomas I H Park
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.,Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Henry J Waldvogel
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.,Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.,Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Edward W Mee
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.,Department of Neurosurgery, Auckland City Hospital, Auckland, New Zealand
| | - Peter S Bergin
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.,Department of Neurology, Auckland City Hospital, Auckland, New Zealand
| | - Richard L M Faull
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.,Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Mike Dragunow
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.,Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Maurice A Curtis
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand. .,Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.
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10
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Vyas Y, Jung Y, Lee K, Garner CC, Montgomery JM. In vitro zinc supplementation alters synaptic deficits caused by autism spectrum disorder-associated Shank2 point mutations in hippocampal neurons. Mol Brain 2021; 14:95. [PMID: 34167580 PMCID: PMC8223320 DOI: 10.1186/s13041-021-00809-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 06/12/2021] [Indexed: 11/30/2022] Open
Abstract
Autism Spectrum Disorders (ASDs) are neurodevelopmental disorders characterised by deficits in social interactions and repetitive behaviours. ASDs have a strong genetic basis with mutations involved in the development and function of neural circuitry. Shank proteins act as master regulators of excitatory glutamatergic synapses, and Shank mutations have been identified in people with ASD. Here, we have investigated the impact of ASD-associated Shank2 single nucleotide variants (SNVs) at the synaptic level, and the potential of in vitro zinc supplementation to prevent synaptic deficits. Dissociated rat hippocampal cultures expressing enhanced green fluorescent protein (EGFP) tagged Shank2-Wildtype (WT), and ASD-associated Shank2 single nucleotide variants (SNVs: S557N, V717F, and L1722P), were cultured in the absence or presence of 10 μM zinc. In comparison to Shank2-WT, ASD-associated Shank2 SNVs induced significant decreases in synaptic density and reduced the frequency of miniature excitatory postsynaptic currents. These structural and functional ASD-associated synaptic deficits were prevented by chronic zinc supplementation and further support zinc supplementation as a therapeutic target in ASD.
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Affiliation(s)
- Yukti Vyas
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Yewon Jung
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Kevin Lee
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Craig C Garner
- German Center for Neurodegenerative Diseases, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Johanna M Montgomery
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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11
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Abstract
Microglia are the primary innate immune effectors of the central nervous system. Although numerous protocols have been developed to isolate fetal mouse microglia, the isolation of adult mouse microglia has proven more difficult. Here, we present a simple, widely accessible protocol to isolate pure microglia cultures from 4- to 14-month-old mouse brains using their adherent properties in vitro. These isolated microglia recapitulate the adherent properties of adult human microglia and present a more suitable model for studying age-related diseases. For complete details on the use and execution of this protocol in adult human microglia, please refer to Rustenhoven et al. (2016).
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Affiliation(s)
- Zoe Woolf
- Department of Pharmacology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, Private Bag 92019, New Zealand
- Centre for Brain Research, The University of Auckland, Auckland, Private Bag 92019, New Zealand
| | - Taylor J. Stevenson
- Centre for Brain Research, The University of Auckland, Auckland, Private Bag 92019, New Zealand
- Department of Anatomy and Medical Imaging, The University of Auckland, Auckland, Private Bag 92019, New Zealand
| | - Kevin Lee
- Centre for Brain Research, The University of Auckland, Auckland, Private Bag 92019, New Zealand
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, Private Bag 92019, New Zealand
| | - Yewon Jung
- Centre for Brain Research, The University of Auckland, Auckland, Private Bag 92019, New Zealand
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, Private Bag 92019, New Zealand
| | - Thomas I.H. Park
- Department of Pharmacology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, Private Bag 92019, New Zealand
- Centre for Brain Research, The University of Auckland, Auckland, Private Bag 92019, New Zealand
| | - Maurice A. Curtis
- Centre for Brain Research, The University of Auckland, Auckland, Private Bag 92019, New Zealand
- Department of Anatomy and Medical Imaging, The University of Auckland, Auckland, Private Bag 92019, New Zealand
| | - Johanna M. Montgomery
- Centre for Brain Research, The University of Auckland, Auckland, Private Bag 92019, New Zealand
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, Private Bag 92019, New Zealand
| | - Michael Dragunow
- Department of Pharmacology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, Private Bag 92019, New Zealand
- Centre for Brain Research, The University of Auckland, Auckland, Private Bag 92019, New Zealand
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12
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Winbo A, Ramanan S, Eugster E, Rydberg A, Jovinge S, Skinner JR, Montgomery JM. Functional hyperactivity in long QT syndrome type 1 pluripotent stem cell-derived sympathetic neurons. Am J Physiol Heart Circ Physiol 2021; 321:H217-H227. [PMID: 34142889 DOI: 10.1152/ajpheart.01002.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sympathetic activation is an established trigger of life-threatening cardiac events in long QT syndrome type 1 (LQT1). KCNQ1 loss-of-function variants, which underlie LQT1, have been associated with both cardiac arrhythmia and neuronal hyperactivity pathologies. However, the LQT1 sympathetic neuronal phenotype is unknown. Here, we aimed to study human induced pluripotent stem cell (hiPSC)-derived sympathetic neurons (SNs) to evaluate neuronal functional phenotype in LQT1. We generated hiPSC-SNs from two patients with LQT1 with a history of sympathetically triggered arrhythmia and KCNQ1 loss-of-function genotypes (c.781_782delinsTC and p.S349W/p.R518X). Characterization of hiPSC-SNs was performed using immunohistochemistry, enzyme-linked immunosorbent assay, and whole cell patch clamp electrophysiology, and functional LQT1 hiPSC-SN phenotypes compared with healthy control (WT) hiPSC-SNs. hiPSC-SNs stained positive for tyrosine hydroxylase, peripherin, KCNQ1, and secreted norepinephrine. hiPSC-SNs at 60 ± 2.2 days in vitro had healthy resting membrane potentials (-60 ± 1.3 mV), and fired rapid action potentials with mature kinetics in response to stimulation. Significant hyperactivity in LQT1 hiPSC-SNs was evident via increased norepinephrine release, increased spontaneous action potential frequency, increased total inward current density, and reduced afterhyperpolarization, compared with age-matched WT hiPSC-SNs. A significantly higher action potential frequency upon current injection and larger synaptic current amplitudes in compound heterozygous p.S349W/p.R518X hiPSC-SNs compared with heterozygous c.781_782delinsTC hiPSC-SNs was also observed, suggesting a potential genotype-phenotype correlation. Together, our data reveal increased neurotransmission and excitability in heterozygous and compound heterozygous patient-derived LQT1 sympathetic neurons, suggesting that the cellular arrhythmogenic potential in LQT1 is not restricted to cardiomyocytes.NEW & NOTEWORTHY Here, we present the first study of patient-derived LQT1 sympathetic neurons that are norepinephrine secreting, and electrophysiologically functional, in vitro. Our data reveal a novel LQT1 sympathetic neuronal phenotype of increased neurotransmission and excitability. The identified sympathetic neuronal hyperactivity phenotype is of particular relevance as it could contribute to the mechanisms underlying sympathetically triggered arrhythmia in LQT1.
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Affiliation(s)
- Annika Winbo
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand.,Department of Paediatric and Congenital Cardiac Services, Starship Children's Hospital, Auckland, New Zealand.,The Cardiac Inherited Disease Group (CIDG), Auckland, New Zealand.,Department of Clinical Sciences, Pediatrics, Umeå University, Umeå, Sweden
| | - Suganeya Ramanan
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Emily Eugster
- DeVos Cardiovascular Research Program Spectrum Health/Van Andel Research Institute, Grand Rapids, Michigan
| | - Annika Rydberg
- Department of Clinical Sciences, Pediatrics, Umeå University, Umeå, Sweden
| | - Stefan Jovinge
- DeVos Cardiovascular Research Program Spectrum Health/Van Andel Research Institute, Grand Rapids, Michigan.,Cardiovascular Institute, Stanford University of Medicine, Stanford, California
| | - Jonathan R Skinner
- Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand.,Department of Paediatric and Congenital Cardiac Services, Starship Children's Hospital, Auckland, New Zealand.,The Cardiac Inherited Disease Group (CIDG), Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
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13
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Winbo A, Ramanan S, Eugster E, Jovinge S, Skinner JR, Montgomery JM. Functional coculture of sympathetic neurons and cardiomyocytes derived from human-induced pluripotent stem cells. Am J Physiol Heart Circ Physiol 2020; 319:H927-H937. [DOI: 10.1152/ajpheart.00546.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We present data on a functional coculture between human-induced pluripotent stem cell-derived sympathetic neurons and cardiomyocytes. Moreover, this study adds significantly to the available data on the electrophysiological function of human-induced pluripotent stem cell-derived sympathetic neurons.
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Affiliation(s)
- Annika Winbo
- Department of Physiology, The University of Auckland, Auckland, New Zealand
- Manaaki Mānawa Centre for Heart Research, The University of Auckland, Auckland, New Zealand
- Department of Paediatric and Congenital Cardiac Services, Starship Children’s Hospital, Auckland, New Zealand
| | - Suganeya Ramanan
- Department of Physiology, The University of Auckland, Auckland, New Zealand
- Manaaki Mānawa Centre for Heart Research, The University of Auckland, Auckland, New Zealand
| | - Emily Eugster
- DeVos Cardiovascular Research Program, Spectrum Health and Van Andel Research Institute, Grand Rapids, Michigan
| | - Stefan Jovinge
- DeVos Cardiovascular Research Program, Spectrum Health and Van Andel Research Institute, Grand Rapids, Michigan
- Cardiovascular Institute, Stanford University, Palo Alto, California
| | - Jonathan R. Skinner
- Manaaki Mānawa Centre for Heart Research, The University of Auckland, Auckland, New Zealand
- Department of Paediatric and Congenital Cardiac Services, Starship Children’s Hospital, Auckland, New Zealand
| | - Johanna M. Montgomery
- Department of Physiology, The University of Auckland, Auckland, New Zealand
- Manaaki Mānawa Centre for Heart Research, The University of Auckland, Auckland, New Zealand
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14
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Tedoldi A, Argent L, Montgomery JM. The role of the tripartite synapse in the heart: how glial cells may contribute to the physiology and pathophysiology of the intracardiac nervous system. Am J Physiol Cell Physiol 2020; 320:C1-C14. [PMID: 33085497 DOI: 10.1152/ajpcell.00363.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
One of the major roles of the intracardiac nervous system (ICNS) is to act as the final site of signal integration for efferent information destined for the myocardium to enable local control of heart rate and rhythm. Multiple subtypes of neurons exist in the ICNS where they are organized into clusters termed ganglionated plexi (GP). The majority of cells in the ICNS are actually glial cells; however, despite this, ICNS glial cells have received little attention to date. In the central nervous system, where glial cell function has been widely studied, glia are no longer viewed simply as supportive cells but rather have been shown to play an active role in modulating neuronal excitability and synaptic plasticity. Pioneering studies have demonstrated that in addition to glia within the brain stem, glial cells within multiple autonomic ganglia in the peripheral nervous system, including the ICNS, can also act to modulate cardiovascular function. Clinically, patients with atrial fibrillation (AF) undergoing catheter ablation show high plasma levels of S100B, a protein produced by cardiac glial cells, correlated with decreased AF recurrence. Interestingly, S100B also alters GP neuron excitability and neurite outgrowth in the ICNS. These studies highlight the importance of understanding how glial cells can affect the heart by modulating GP neuron activity or synaptic inputs. Here, we review studies investigating glia both in the central and peripheral nervous systems to discuss the potential role of glia in controlling cardiac function in health and disease, paying particular attention to the glial cells of the ICNS.
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Affiliation(s)
- Angelo Tedoldi
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Liam Argent
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
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15
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Park TIH, Schweder P, Lee K, Dieriks BV, Jung Y, Smyth L, Rustenhoven J, Mee E, Heppner P, Turner C, Curtis MA, Faull RLM, Montgomery JM, Dragunow M. Isolation and culture of functional adult human neurons from neurosurgical brain specimens. Brain Commun 2020; 2:fcaa171. [PMID: 33215086 PMCID: PMC7660143 DOI: 10.1093/braincomms/fcaa171] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 08/20/2020] [Accepted: 08/28/2020] [Indexed: 12/14/2022] Open
Abstract
The ability to characterize and study primary neurons isolated directly from the adult human brain would greatly advance neuroscience research. However, significant challenges such as accessibility of human brain tissue and the lack of a robust neuronal cell culture protocol have hampered its progress. Here, we describe a simple and reproducible method for the isolation and culture of functional adult human neurons from neurosurgical brain specimens. In vitro, adult human neurons form a dense network and express a plethora of mature neuronal and synaptic markers. Most importantly, for the first time, we demonstrate the re-establishment of mature neurophysiological properties in vitro, such as repetitive fast-spiking action potentials, and spontaneous and evoked synaptic activity. Together, our dissociated and slice culture systems enable studies of adult human neurophysiology and gene expression under normal and pathological conditions and provide a high-throughput platform for drug testing on brain cells directly isolated from the adult human brain.
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Affiliation(s)
- Thomas I-H Park
- Department of Pharmacology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Patrick Schweder
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Kevin Lee
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Birger V Dieriks
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Yewon Jung
- Department of Pharmacology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Leon Smyth
- Department of Pharmacology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Justin Rustenhoven
- Department of Pharmacology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Edward Mee
- Department of Neurosurgery, Auckland City Hospital, Auckland, New Zealand
| | - Peter Heppner
- Department of Neurosurgery, Auckland City Hospital, Auckland, New Zealand
| | - Clinton Turner
- Department of Anatomical Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand
| | - Maurice A Curtis
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Richard L M Faull
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Michael Dragunow
- Department of Pharmacology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
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16
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Vyas Y, Lee K, Jung Y, Montgomery JM. Influence of maternal zinc supplementation on the development of autism-associated behavioural and synaptic deficits in offspring Shank3-knockout mice. Mol Brain 2020; 13:110. [PMID: 32758248 PMCID: PMC7409418 DOI: 10.1186/s13041-020-00650-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 07/30/2020] [Indexed: 11/10/2022] Open
Abstract
Autism Spectrum Disorders (ASD) are characterised by deficits in social interactions and repetitive behaviours. Multiple ASD-associated mutations have been identified in the Shank family of proteins that play a critical role in the structure and plasticity of glutamatergic synapses, leading to impaired synapse function and the presentation of ASD-associated behavioural deficits in mice. Shank proteins are highly regulated by zinc, where zinc binds the Shank SAM domain to drive synaptic protein recruitment and synaptic maturation. Here we have examined the influence of maternal dietary zinc supplementation during pregnancy and lactation on the development of ASD-associated behavioural and synaptic changes in the offspring Shank3 knockout (Shank3−/−) mice. Behavioural and electrophysiological experiments were performed in juvenile and adult Shank3−/− and wildtype littermate control mice born from mothers fed control (30 ppm, ppm) or supplemented (150 ppm) dietary zinc. We observed that the supplemented maternal zinc diet prevented ASD-associated deficits in social interaction and normalised anxiety behaviours in Shank3−/− offspring mice. These effects were maintained into adulthood. Repetitive grooming was also prevented in adult Shank3−/− offspring mice. At the synaptic level, maternal zinc supplementation altered postsynaptic NMDA receptor-mediated currents and presynaptic function at glutamatergic synapses onto medium spiny neurons in the cortico-striatal pathway of the Shank3−/− offspring mice. These data show that increased maternal dietary zinc during pregnancy and lactation can alter the development of ASD-associated changes at the synaptic and the behavioural levels, and that zinc supplementation from the beginning of brain development can prevent ASD-associated deficits in Shank3−/− mice long term.
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Affiliation(s)
- Yukti Vyas
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Kevin Lee
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Yewon Jung
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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17
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Aqrawe Z, Patel N, Montgomery JM, Travas-Sejdic J, Svirskis D. Development of a Low Cost & Low Noise Amplification System For In Vitro Neuronal Recording through Microelectrode Arrays .. Annu Int Conf IEEE Eng Med Biol Soc 2020; 2019:6055-6058. [PMID: 31947226 DOI: 10.1109/embc.2019.8857196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In order to effectively record from electrically active cells through microelectrode arrays a low-noise amplification and data acquisition system is required. Although commercially available, these systems can be expensive and lack the freedom to customise hardware and software. In this work we present a low-cost (US$21 for the first channel + US$11 for each additional channel), low-noise amplifier coupled with an analog to digital converter from National Instruments. The amplifier was designed to (i) operate between 0 and 5 V utilising a DC battery power supply, (ii) operate within a bandwidth of 10 kHz, (iii) remove DC voltage created at the electrode/electrolyte interface with a high-pass cut-off frequency of 0.7 Hz and (iv) have a gain of 2000. Strategies to reduce environment electromagnetic interference at the amplifier front end were employed and involved a customised neural interface board connected between the microelectrode array and amplifier. The constructed amplifier achieved an intrinsic noise amplitude of 0.8 μVrms, which facilitated high quality recordings as exemplified by in vitro recordings from primary hippocampal neurons.
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18
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Sigalas C, Cremer M, Winbo A, Bose SJ, Ashton JL, Bub G, Montgomery JM, Burton RAB. Combining tissue engineering and optical imaging approaches to explore interactions along the neuro-cardiac axis. R Soc Open Sci 2020; 7:200265. [PMID: 32742694 PMCID: PMC7353978 DOI: 10.1098/rsos.200265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/27/2020] [Indexed: 05/05/2023]
Abstract
Interactions along the neuro-cardiac axis are being explored with regard to their involvement in cardiac diseases, including catecholaminergic polymorphic ventricular tachycardia, hypertension, atrial fibrillation, long QT syndrome and sudden death in epilepsy. Interrogation of the pathophysiology and pathogenesis of neuro-cardiac diseases in animal models present challenges resulting from species differences, phenotypic variation, developmental effects and limited availability of data relevant at both the tissue and cellular level. By contrast, tissue-engineered models containing cardiomyocytes and peripheral sympathetic and parasympathetic neurons afford characterization of cellular- and tissue-level behaviours while maintaining precise control over developmental conditions, cellular genotype and phenotype. Such approaches are uniquely suited to long-term, high-throughput characterization using optical recording techniques with the potential for increased translational benefit compared to more established techniques. Furthermore, tissue-engineered constructs provide an intermediary between whole animal/tissue experiments and in silico models. This paper reviews the advantages of tissue engineering methods of multiple cell types and optical imaging techniques for the characterization of neuro-cardiac diseases.
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Affiliation(s)
| | - Maegan Cremer
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Annika Winbo
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Department of Paediatric and Congenital Cardiac Services, Starship Children's Hospital, Auckland, New Zealand
| | - Samuel J. Bose
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Jesse L. Ashton
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Gil Bub
- Department of Physiology, McGill University, Montreal, Canada
| | | | - Rebecca A. B. Burton
- Department of Pharmacology, University of Oxford, Oxford, UK
- Author for correspondence: Rebecca A. B. Burton e-mail:
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19
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Ashton JL, Argent L, Smith JEG, Jin S, Sands GB, Smaill BH, Montgomery JM. Evidence of structural and functional plasticity occurring within the intracardiac nervous system of spontaneously hypertensive rats. Am J Physiol Heart Circ Physiol 2020; 318:H1387-H1400. [DOI: 10.1152/ajpheart.00020.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We have developed intracardiac neuron whole cell recording techniques in atrial preparations from control and spontaneous hypertensive rats. This has enabled the identification of significant synaptic plasticity in the intracardiac nervous system, including enhanced postsynaptic current frequency, increased synaptic terminal density, and altered postsynaptic receptors. This increased synaptic drive together with altered cardiac neuron electrophysiology could increase intracardiac nervous system excitability and contribute to the substrate for atrial arrhythmia in hypertensive heart disease.
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Affiliation(s)
- Jesse L. Ashton
- Department of Physiology, Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Liam Argent
- Department of Physiology, Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Joscelin E. G. Smith
- Department of Physiology, Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Sangjun Jin
- Department of Physiology, Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Gregory B. Sands
- Department of Physiology, Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
- Bioengineering Institute, Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Bruce H. Smaill
- Department of Physiology, Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
- Bioengineering Institute, Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Johanna M. Montgomery
- Department of Physiology, Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
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20
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Abstract
Plasticity within the neuronal networks of the brain underlies the ability to learn and retain new information. The initial discovery of synaptic plasticity occurred by measuring synaptic strength in vivo, applying external stimulation and observing an increase in synaptic strength termed long-term potentiation (LTP). Many of the molecular pathways involved in LTP and other forms of synaptic plasticity were subsequently uncovered in vitro. Over the last few decades, technological advances in recording and imaging in live animals have seen many of these molecular mechanisms confirmed in vivo, including structural changes both pre- and postsynaptically, changes in synaptic strength, and changes in neuronal excitability. A well-studied aspect of neuronal plasticity is the capacity of the brain to adapt to its environment, gained by comparing the brains of deprived and experienced animals in vivo, and in direct response to sensory stimuli. Multiple in vivo studies have also strongly linked plastic changes to memory by interfering with the expression of plasticity and by manipulating memory engrams. Plasticity in vivo also occurs in the absence of any form of external stimulation, i.e., during spontaneous network activity occurring with brain development. However, there is still much to learn about how plasticity is induced during natural learning and how this is altered in neurological disorders.
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Affiliation(s)
- Juliette E Cheyne
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
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21
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Vyas Y, Montgomery JM, Cheyne JE. Hippocampal Deficits in Amyloid-β-Related Rodent Models of Alzheimer's Disease. Front Neurosci 2020; 14:266. [PMID: 32317913 PMCID: PMC7154147 DOI: 10.3389/fnins.2020.00266] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 03/09/2020] [Indexed: 12/18/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease that is the most common cause of dementia. Symptoms of AD include memory loss, disorientation, mood and behavior changes, confusion, unfounded suspicions, and eventually, difficulty speaking, swallowing, and walking. These symptoms are caused by neuronal degeneration and cell loss that begins in the hippocampus, and later in disease progression spreading to the rest of the brain. While there are some medications that alleviate initial symptoms, there are currently no treatments that stop disease progression. Hippocampal deficits in amyloid-β-related rodent models of AD have revealed synaptic, behavioral and circuit-level defects. These changes in synaptic function, plasticity, neuronal excitability, brain connectivity, and excitation/inhibition imbalance all have profound effects on circuit function, which in turn could exacerbate disease progression. Despite, the wealth of studies on AD pathology we don't yet have a complete understanding of hippocampal deficits in AD. With the increasing development of in vivo recording techniques in awake and freely moving animals, future studies will extend our current knowledge of the mechanisms underpinning how hippocampal function is altered in AD, and aid in progression of treatment strategies that prevent and/or delay AD symptoms.
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Affiliation(s)
| | - Johanna M. Montgomery
- Department of Physiology, Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Juliette E. Cheyne
- Department of Physiology, Centre for Brain Research, University of Auckland, Auckland, New Zealand
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22
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Winbo A, Ashton JL, Montgomery JM. Neuroscience in the heart: Recent advances in neurocardiac communication and its role in cardiac arrhythmias. Int J Biochem Cell Biol 2020; 122:105737. [PMID: 32151724 DOI: 10.1016/j.biocel.2020.105737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/13/2020] [Accepted: 03/05/2020] [Indexed: 12/14/2022]
Abstract
Autonomic nervous system dysregulation is involved in the pathophysiology of multiple cardiac arrhythmias, and therefore modulating sympathetic or parasympathetic input to the heart provides novel therapeutic options for arrhythmia management. Examples include decreasing intrinsic cardiac neuron communication, patterned vagal nerve stimulation, denervation, and blockade of post-ganglionic neurons. However, lessons from ventricular arrhythmias, where increased sympathetic activity and vagal rebound activity both amplify arrhythmia risk, stress the importance of understanding the regulatory mechanisms that modulate the balance and levels of sympathetic and parasympathetic activity. Of critical need is an increased understanding of plasticity mechanisms in the autonomic nervous system, to a level similar to what is known in the central nervous system, in order to develop safe and effective neuromodulatory therapies.
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Affiliation(s)
- Annika Winbo
- Department of Physiology and Manaaki Mānawa Centre for Heart Research, University of Auckland, New Zealand; Auckland District Health Board, Auckland, New Zealand
| | - Jesse L Ashton
- Department of Physiology and Manaaki Mānawa Centre for Heart Research, University of Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology and Manaaki Mānawa Centre for Heart Research, University of Auckland, New Zealand.
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23
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Lee K, Park TIH, Heppner P, Schweder P, Mee EW, Dragunow M, Montgomery JM. Human in vitro systems for examining synaptic function and plasticity in the brain. J Neurophysiol 2020; 123:945-965. [PMID: 31995449 DOI: 10.1152/jn.00411.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The human brain shows remarkable complexity in its cellular makeup and function, which are distinct from nonhuman species, signifying the need for human-based research platforms for the study of human cellular neurophysiology and neuropathology. However, the use of adult human brain tissue for research purposes is hampered by technical, methodological, and accessibility challenges. One of the major problems is the limited number of in vitro systems that, in contrast, are readily available from rodent brain tissue. With recent advances in the optimization of protocols for adult human brain preparations, there is a significant opportunity for neuroscientists to validate their findings in human-based systems. This review addresses the methodological aspects, advantages, and disadvantages of human neuron in vitro systems, focusing on the unique properties of human neurons and synapses in neocortical microcircuits. These in vitro models provide the incomparable advantage of being a direct representation of the neurons that have formed part of the human brain until the point of recording, which cannot be replicated by animal models nor human stem-cell systems. Important distinct cellular mechanisms are observed in human neurons that may underlie the higher order cognitive abilities of the human brain. The use of human brain tissue in neuroscience research also raises important ethical, diversity, and control tissue limitations that need to be considered. Undoubtedly however, these human neuron systems provide critical information to increase the potential of translation of treatments from the laboratory to the clinic in a way animal models are failing to provide.
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Affiliation(s)
- Kevin Lee
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Centre for Brain Research, University of Auckland, New Zealand
| | - Thomas I-H Park
- Centre for Brain Research, University of Auckland, New Zealand.,Department of Pharmacology, University of Auckland, Auckland, New Zealand
| | - Peter Heppner
- Centre for Brain Research, University of Auckland, New Zealand.,Department of Neurosurgery, Auckland City Hospital, Auckland, New Zealand
| | - Patrick Schweder
- Centre for Brain Research, University of Auckland, New Zealand.,Department of Neurosurgery, Auckland City Hospital, Auckland, New Zealand
| | - Edward W Mee
- Centre for Brain Research, University of Auckland, New Zealand.,Department of Neurosurgery, Auckland City Hospital, Auckland, New Zealand
| | - Michael Dragunow
- Centre for Brain Research, University of Auckland, New Zealand.,Department of Pharmacology, University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Centre for Brain Research, University of Auckland, New Zealand
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24
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Ambroziak W, Fourie C, Montgomery JM. SAP97-mediated rescue of NMDA receptor surface distribution in a neuronal model of Huntington's disease. Hippocampus 2019; 28:707-723. [PMID: 30067285 DOI: 10.1002/hipo.22995] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 04/22/2018] [Accepted: 05/29/2018] [Indexed: 01/10/2023]
Abstract
Huntington's disease (HD) is a genetic neurodegenerative disorder caused by an expansion of the CAG repeat tract in the HTT gene, leading to motor, cognitive, and psychiatric symptoms. At the cellular level, NMDA-type glutamate receptors are upregulated at glutamatergic extrasynaptic sites in HD, triggering cell death signaling pathways and driving HD neurodegeneration. Extrasynaptic and synaptic glutamate receptor trafficking and surface distribution are regulated by the α and β N-terminal isoforms of SAP97, a postsynaptic density protein localized at glutamatergic synapses. Here we examined the surface distribution of NMDARs and AMPARs in a cellular model of HD, and whether the manipulation of individual SAP97 isoforms can regulate receptor distribution in diseased neurons. Using dSTORM super-resolution imaging, we reveal that mutant HTT drives the elevation of extrasynaptic NMDAR clusters located 100-500 nm from the postsynaptic density. This was accompanied by a decline in synaptic NMDAR-mediated currents while surface NMDAR-mediated currents remained unchanged. These effects were induced within 3 days of mutant HTT expression in rat hippocampal neurons in vitro, and were specific for NMDARs and not observed with AMPARs. Intriguingly, upregulation of either α- or βSAP97 expression increased synaptic and/or perisynaptic NMDAR localization and prevented the shift of NMDARs to extrasynaptic sites in mutant HTT neurons. This was accompanied by the rescue of normal synaptic NMDAR-mediated currents. Taken together, our high-resolution data reveals plasticity in surface NMDAR localization driven by mutant HTT and identifies the similar but independent roles of SAP97 N-terminal isoforms in maintaining normal synaptic function in pathological states.
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Affiliation(s)
- Wojciech Ambroziak
- Department of Physiology and Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - Chantelle Fourie
- Department of Physiology and Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology and Centre for Brain Research, The University of Auckland, Auckland, New Zealand
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25
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Lee K, Vyas Y, Garner CC, Montgomery JM. Autism‐associated
Shank3
mutations alter mGluR expression and mGluR‐dependent but not NMDA receptor‐dependent long‐term depression. Synapse 2019; 73:e22097. [DOI: 10.1002/syn.22097] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 02/20/2019] [Accepted: 03/10/2019] [Indexed: 12/17/2022]
Affiliation(s)
- Kevin Lee
- Department of Physiology, Centre for Brain Research University of Auckland Auckland New Zealand
| | - Yukti Vyas
- Department of Physiology, Centre for Brain Research University of Auckland Auckland New Zealand
| | - Craig C. Garner
- German Center for Neurodegenerative Disorders Charité – Universitätsmedizin Berlin Berlin Germany
| | - Johanna M. Montgomery
- Department of Physiology, Centre for Brain Research University of Auckland Auckland New Zealand
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26
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Montgomery JM, Lipp MJ. Advanced Spectral Analysis Program. Rev Sci Instrum 2019; 90:023903. [PMID: 30831719 DOI: 10.1063/1.5048311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 01/18/2019] [Indexed: 06/09/2023]
Abstract
Advanced Spectral Analysis Program is a LabVIEW-based program intended for rapid and accurate analysis of large sets of spectral data. It can handle a range of different types of data including angle-resolved and energy-dispersive powder diffraction and Raman spectra. We present it here with a focus on high-temperature high-pressure powder diffraction. The program contains a novel graphical user interface that allows rapid manual fitting and indexing of peaks which require precise fitting ranges and includes tools for fitting any Bravais lattice and arbitrary user-defined multivariate equations of state. The program allows the user to simultaneously view and manipulate multiple data sets from an experiment. The user can save and load analysis progress at any point, allowing for repeatable calculations to be performed, and to allow the fast comparison of different analysis parameters.
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Affiliation(s)
- J M Montgomery
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - M J Lipp
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
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27
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Montgomery JM, Lipp MJ, Jenei Z, Meng Y, Evans WJ. A simple and portable multi-channel pyrometer allowing temperature measurements down to 800 K on the microsecond scale. Rev Sci Instrum 2018; 89:125117. [PMID: 30599546 DOI: 10.1063/1.5048784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 12/02/2018] [Indexed: 06/09/2023]
Abstract
The measurement of transient temperatures less than 1000 K for samples in laser-heated diamond anvil cells remains a challenge. Here we present the design and performance characteristics of a multi-channel pyrometer that works in the near-infrared from 1200 to 2000 nm. It has a relatively small footprint, is portable, requires only low voltage power supplies, and can report temperatures down to 800 K on the millisecond scale or faster. A single data point without averaging can be acquired in 14 µs (sampling rate of 7 kilosamples per second). In conjunction with a diamond anvil cell, the system delivers accurate and rapid measurements down to ∼830 K. The pyrometer has been successfully interfaced several times with the combined x-ray diffraction and laser heating system at the High Pressure Collaborative Access Team at the Advanced Photon Source at Argonne National Laboratories.
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Affiliation(s)
- J M Montgomery
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - M J Lipp
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Zs Jenei
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Y Meng
- HPCAT, Geophysical Laboratory, Carnegie Institute of Washington, Argonne, Illinois 60439, USA
| | - W J Evans
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
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28
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Ha HTT, Leal-Ortiz S, Lalwani K, Kiyonaka S, Hamachi I, Mysore SP, Montgomery JM, Garner CC, Huguenard JR, Kim SA. Shank and Zinc Mediate an AMPA Receptor Subunit Switch in Developing Neurons. Front Mol Neurosci 2018; 11:405. [PMID: 30524232 PMCID: PMC6256285 DOI: 10.3389/fnmol.2018.00405] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/15/2018] [Indexed: 11/18/2022] Open
Abstract
During development, pyramidal neurons undergo dynamic regulation of AMPA receptor (AMPAR) subunit composition and density to help drive synaptic plasticity and maturation. These normal developmental changes in AMPARs are particularly vulnerable to risk factors for Autism Spectrum Disorders (ASDs), which include loss or mutations of synaptic proteins and environmental insults, such as dietary zinc deficiency. Here, we show how Shank2 and Shank3 mediate a zinc-dependent regulation of AMPAR function and subunit switch from GluA2-lacking to GluA2-containing AMPARs. Over development, we found a concomitant increase in Shank2 and Shank3 with GluA2 at synapses, implicating these molecules as potential players in AMPAR maturation. Since Shank activation and function require zinc, we next studied whether neuronal activity regulated postsynaptic zinc at glutamatergic synapses. Zinc was found to increase transiently and reversibly with neuronal depolarization at synapses, which could affect Shank and AMPAR localization and activity. Elevated zinc induced multiple functional changes in AMPAR, indicative of a subunit switch. Specifically, zinc lengthened the decay time of AMPAR-mediated synaptic currents and reduced their inward rectification in young hippocampal neurons. Mechanistically, both Shank2 and Shank3 were necessary for the zinc-sensitive enhancement of AMPAR-mediated synaptic transmission and act in concert to promote removal of GluA1 while enhancing recruitment of GluA2 at pre-existing Shank puncta. These findings highlight a cooperative local dynamic regulation of AMPAR subunit switch controlled by zinc signaling through Shank2 and Shank3 to shape the biophysical properties of developing glutamatergic synapses. Given the zinc sensitivity of young neurons and its dependence on Shank2 and Shank3, genetic mutations and/or environmental insults during early development could impair synaptic maturation and circuit formation that underlie ASD etiology.
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Affiliation(s)
- Huong T T Ha
- Department of Neurology & Neurological Sciences, School of Medicine, Stanford University, Stanford, CA, United States.,Neurosciences Graduate Program, School of Medicine, Stanford University, Stanford, CA, United States
| | - Sergio Leal-Ortiz
- Department of Material Science & Engineering, School of Engineering, Stanford University, Stanford, CA, United States
| | - Kriti Lalwani
- Department of Neurology & Neurological Sciences, School of Medicine, Stanford University, Stanford, CA, United States
| | - Shigeki Kiyonaka
- Department of Synthetic Chemistry & Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Itaru Hamachi
- Department of Synthetic Chemistry & Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Shreesh P Mysore
- Department of Psychological & Brain Sciences, Johns Hopkins University, Baltimore, MD, United States
| | - Johanna M Montgomery
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Craig C Garner
- German Center for Neurodegenerative Diseases (DZNE), Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - John R Huguenard
- Department of Neurology & Neurological Sciences, School of Medicine, Stanford University, Stanford, CA, United States
| | - Sally A Kim
- Department of Neurology & Neurological Sciences, School of Medicine, Stanford University, Stanford, CA, United States
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29
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Fourie C, Vyas Y, Lee K, Jung Y, Garner CC, Montgomery JM. Dietary Zinc Supplementation Prevents Autism Related Behaviors and Striatal Synaptic Dysfunction in Shank3 Exon 13-16 Mutant Mice. Front Cell Neurosci 2018; 12:374. [PMID: 30405356 PMCID: PMC6204368 DOI: 10.3389/fncel.2018.00374] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 10/01/2018] [Indexed: 12/27/2022] Open
Abstract
The SHANK family of synaptic proteins (SHANK1–3) are master regulators of the organizational structure of excitatory synapses in the brain. Mutations in SHANK1–3 are prevalent in patients with autism spectrum disorders (ASD), and loss of one copy of SHANK3 causes Phelan-McDermid Syndrome, a syndrome in which Autism occurs in >80% of cases. The synaptic stability of SHANK3 is highly regulated by zinc, driving the formation of postsynaptic protein complexes and increases in excitatory synaptic strength. As ASD-associated SHANK3 mutations retain responsiveness to zinc, here we investigated how increasing levels of dietary zinc could alter behavioral and synaptic deficits that occur with ASD. We performed behavioral testing together with cortico-striatal slice electrophysiology on a Shank3−/− mouse model of ASD (Shank3ex13–1616−/−), which displays ASD-related behaviors and structural and functional deficits at striatal synapses. We observed that 6 weeks of dietary zinc supplementation in Shank3ex13–16−/− mice prevented ASD-related repetitive and anxiety behaviors and deficits in social novelty recognition. Dietary zinc supplementation also increased the recruitment of zinc sensitive SHANK2 to synapses, reduced synaptic transmission specifically through N-methyl-D-aspartate (NMDA)-type glutamate receptors, reversed the slowed decay tau of NMDA receptor (NMDAR)-mediated currents and occluded long term potentiation (LTP) at cortico-striatal synapses. These data suggest that alterations in NMDAR function underlie the lack of NMDAR-dependent cortico-striatal LTP and contribute to the reversal of ASD-related behaviors such as compulsive grooming. Our data reveal that dietary zinc alters neurological function from synapses to behavior, and identifies dietary zinc as a potential therapeutic agent in ASD.
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Affiliation(s)
- Chantelle Fourie
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Yukti Vyas
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Kevin Lee
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Yewon Jung
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Craig C Garner
- German Center for Neurodegenerative Disorders, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Johanna M Montgomery
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
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30
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Hoggard M, Vesty A, Wong G, Montgomery JM, Fourie C, Douglas RG, Biswas K, Taylor MW. Characterizing the Human Mycobiota: A Comparison of Small Subunit rRNA, ITS1, ITS2, and Large Subunit rRNA Genomic Targets. Front Microbiol 2018; 9:2208. [PMID: 30283425 PMCID: PMC6157398 DOI: 10.3389/fmicb.2018.02208] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Accepted: 08/29/2018] [Indexed: 12/28/2022] Open
Abstract
Interest in the human microbiome has increased dramatically in the last decade. However, much of this research has focused on bacteria, while the composition and roles of their fungal counterparts remain less understood. Furthermore, a variety of methodological approaches have been applied, and the comparability between studies is unclear. This study compared four primer pairs targeting the small subunit (SSU) rRNA (18S), ITS1, ITS2, and large subunit (LSU) rRNA (26S) genomic regions for their ability to accurately characterize fungal communities typical of the human mycobiota. All four target regions of 21 individual fungal mock community taxa were capable of being amplified adequately and sequenced. Mixed mock community analyses revealed marked variability in the ability of each primer pair to accurately characterize a complex community. ITS target regions outperformed LSU and SSU. Of the ITS regions, ITS1 failed to generate sequences for Yarrowia lipolytica and all three Malassezia species when in a mixed community. These findings were further supported in studies of human sinonasal and mouse fecal samples. Based on these analyses, previous studies using ITS1, SSU, or LSU markers may omit key taxa that are identified by the ITS2 marker. Of methods commonly used in human mycobiota studies to date, we recommend selection of the ITS2 marker. Further investigation of more recently developed fungal primer options will be essential to ultimately determine the optimal methodological approach by which future human mycobiota studies ought to be standardized.
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Affiliation(s)
- Michael Hoggard
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Anna Vesty
- School of Medicine, The University of Auckland, Auckland, New Zealand.,Microbiology Laboratory, LabPLUS, Auckland City Hospital, Auckland, New Zealand
| | - Giselle Wong
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology, Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - Chantelle Fourie
- Department of Physiology, Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - Richard G Douglas
- School of Medicine, The University of Auckland, Auckland, New Zealand
| | - Kristi Biswas
- School of Medicine, The University of Auckland, Auckland, New Zealand
| | - Michael W Taylor
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
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31
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Ashton JL, Burton RAB, Bub G, Smaill BH, Montgomery JM. Synaptic Plasticity in Cardiac Innervation and Its Potential Role in Atrial Fibrillation. Front Physiol 2018; 9:240. [PMID: 29615932 PMCID: PMC5869186 DOI: 10.3389/fphys.2018.00240] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 03/06/2018] [Indexed: 12/30/2022] Open
Abstract
Synaptic plasticity is defined as the ability of synapses to change their strength of transmission. Plasticity of synaptic connections in the brain is a major focus of neuroscience research, as it is the primary mechanism underpinning learning and memory. Beyond the brain however, plasticity in peripheral neurons is less well understood, particularly in the neurons innervating the heart. The atria receive rich innervation from the autonomic branch of the peripheral nervous system. Sympathetic neurons are clustered in stellate and cervical ganglia alongside the spinal cord and extend fibers to the heart directly innervating the myocardium. These neurons are major drivers of hyperactive sympathetic activity observed in heart disease, ventricular arrhythmias, and sudden cardiac death. Both pre- and postsynaptic changes have been observed to occur at synapses formed by sympathetic ganglion neurons, suggesting that plasticity at sympathetic neuro-cardiac synapses is a major contributor to arrhythmias. Less is known about the plasticity in parasympathetic neurons located in clusters on the heart surface. These neuronal clusters, termed ganglionated plexi, or “little brains,” can independently modulate neural control of the heart and stimulation that enhances their excitability can induce arrhythmia such as atrial fibrillation. The ability of these neurons to alter parasympathetic activity suggests that plasticity may indeed occur at the synapses formed on and by ganglionated plexi neurons. Such changes may not only fine-tune autonomic innervation of the heart, but could also be a source of maladaptive plasticity during atrial fibrillation.
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Affiliation(s)
- Jesse L Ashton
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | | | - Gil Bub
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - Bruce H Smaill
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
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32
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Affiliation(s)
- Lucy Goodman
- Department of Physiology and Centre for Brain Research; University of Auckland; Auckland New Zealand
| | - David Baddeley
- Department of Physiology and Centre for Brain Research; University of Auckland; Auckland New Zealand
- Department of Cell Biology; Yale School of Medicine; New Haven Connecticut
| | - Wojciech Ambroziak
- Department of Physiology and Centre for Brain Research; University of Auckland; Auckland New Zealand
| | - Clarissa L. Waites
- Department of Pathology and Cell Biology; Columbia University; New York New York
| | - Craig C. Garner
- German Center for Neurodegenerative Diseases; Charité University; Berlin Germany
| | - Christian Soeller
- Department of Physiology and Centre for Brain Research; University of Auckland; Auckland New Zealand
- Department of Physical and Cell Biology; Physical and Cell Biology, University of Exeter; Exeter United Kingdom
| | - Johanna M. Montgomery
- Department of Physiology and Centre for Brain Research; University of Auckland; Auckland New Zealand
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33
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Goodman L, Baddeley D, Ambroziak W, Waites CL, Garner CC, Soeller C, Montgomery JM. N-terminal SAP97 isoforms differentially regulate synaptic structure and postsynaptic surface pools of AMPA receptors. Hippocampus 2017; 27:668-682. [PMID: 28244171 DOI: 10.1002/hipo.22723] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 02/02/2017] [Accepted: 02/17/2017] [Indexed: 11/07/2022]
Abstract
The location and density of postsynaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors is controlled by scaffolding proteins within the postsynaptic density (PSD). SAP97 is a PSD protein with two N-terminal isoforms, α and β, that have opposing effects on synaptic strength thought to result from differential targeting of AMPA receptors into distinct synaptic versus extrasynaptic locations, respectively. In this study, we have applied dSTORM super resolution imaging in order to localize the synaptic and extrasynaptic pools of AMPA receptors in neurons expressing α or βSAP97. Unexpectedly, we observed that both α and βSAP97 enhanced the localization of AMPA receptors at synapses. However, this occurred via different mechanisms: αSAP97 increased PSD size and consequently the number of receptor binding sites, whilst βSAP97 increased synaptic receptor cluster size and surface AMPA receptor density at the PSD edge and surrounding perisynaptic sites without changing PSD size. αSAP97 also strongly enlarged presynaptic active zone protein clusters, consistent with both presynaptic and postsynaptic enhancement underlying the previously observed αSAP97-induced increase in AMPA receptor-mediated currents. In contrast, βSAP97-expressing neurons increased the proportion of immature filopodia that express higher levels of AMPA receptors, decreased the number of functional presynaptic terminals, and also reduced the size of the dendritic tree and delayed the maturation of mushroom spines. Our data reveal that SAP97 isoforms can specifically regulate surface AMPA receptor nanodomain clusters, with βSAP97 increasing extrasynaptic receptor domains at peri-synaptic and filopodial sites. Moreover, βSAP97 negatively regulates synaptic maturation both structurally and functionally. These data support diverging presynaptic and postsynaptic roles of SAP97 N-terminal isoforms in synapse maturation and plasticity. As numerous splice isoforms exist in other major PSD proteins (e.g., Shank, PSD95, and SAP102), this alternative splicing may result in individual PSD proteins having divergent functional and structural roles in both physiological and pathophysiological synaptic states.
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Affiliation(s)
- Lucy Goodman
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - David Baddeley
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand.,Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut
| | - Wojciech Ambroziak
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Clarissa L Waites
- Department of Pathology and Cell Biology, Columbia University, New York, New York
| | - Craig C Garner
- German Center for Neurodegenerative Diseases, Charité University, Berlin, Germany
| | - Christian Soeller
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand.,Department of Physical and Cell Biology, Physical and Cell Biology, University of Exeter, Exeter, United Kingdom
| | - Johanna M Montgomery
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
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34
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Affiliation(s)
- Yukti Vyas
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
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35
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Barclay M, Constable R, James NR, Thorne PR, Montgomery JM. Reduced sensory stimulation alters the molecular make-up of glutamatergic hair cell synapses in the developing cochlea. Neuroscience 2016; 325:50-62. [PMID: 27012610 DOI: 10.1016/j.neuroscience.2016.03.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 02/26/2016] [Accepted: 03/16/2016] [Indexed: 12/20/2022]
Abstract
Neural activity during early development is known to alter innervation pathways in the central and peripheral nervous systems. We sought to examine how reduced sound-induced sensory activity in the cochlea affected the consolidation of glutamatergic synapses between inner hair cells (IHC) and the primary auditory neurons as these synapses play a primary role in transmitting sound information to the brain. A unilateral conductive hearing loss was induced prior to the onset of sound-mediated stimulation of the sensory hair cells, by rupturing the tympanic membrane and dislocating the auditory ossicles in the left ear of P11 mice. Auditory brainstem responses at P15 and P21 showed a 40-50-dB increase in thresholds for frequencies 8-32kHz in the dislocated ear relative to the control ear. Immunohistochemistry and confocal microscopy were subsequently used to examine the effect of this attenuation of sound stimulation on the expression of RIBEYE, which comprises the presynaptic ribbons, Shank-1, a postsynaptic scaffolding protein, and the GluA2/3 and 4 subunits of postsynaptic AMPA receptors. Our results show that dislocation did not alter the number of pre- or postsynaptic protein puncta. However, dislocation did increase the size of RIBEYE, GluA4, GluA2/3 and Shank-1 puncta, with postsynaptic changes preceding presynaptic changes. Our data suggest that a reduction in sound stimulation during auditory development induces plasticity in the molecular make-up of IHC glutamatergic synapses, but does not affect the number of these synapses. Up-regulation of synaptic proteins with sound attenuation may facilitate a compensatory increase in synaptic transmission due to the reduced sensory stimulation of the IHC.
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Affiliation(s)
- M Barclay
- Department of Physiology and Centre for Brain Research, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - R Constable
- Department of Physiology and Centre for Brain Research, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - N R James
- Department of Physiology and Centre for Brain Research, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - P R Thorne
- Department of Physiology and Centre for Brain Research, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Section of Audiology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - J M Montgomery
- Department of Physiology and Centre for Brain Research, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
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36
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Furukawa NW, Teshale EH, Cosmas L, Ochieng M, Gikunju S, Fields BS, Montgomery JM. Serologic evidence for hepatitis E virus infection among patients with undifferentiated acute febrile illness in Kibera, Kenya. J Clin Virol 2016; 77:106-8. [PMID: 26925954 DOI: 10.1016/j.jcv.2016.02.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 02/15/2016] [Accepted: 02/20/2016] [Indexed: 12/27/2022]
Abstract
BACKGROUND Hepatitis E (HEV) is an emerging cause of viral hepatitis mainly transmitted through the fecal-oral route. Residents of the Kibera slum of Nairobi, Kenya are at risk for fecal-orally transmitted infections. OBJECTIVE To quantify the incidence and prevalence of HEV infection among acute febrile illness (AFI) cases using a population-based infectious disease surveillance network. STUDY DESIGN Cross-sectional serum samples from AFI case-patients between 2009 and 2012 were matched to the age and gender distribution of the Kibera population and tested by IgM and IgG enzyme immunoassays (EIA) and nucleic acid testing (NAT). Serum from healthy residents was also tested by EIA. RESULTS Of the 482 AFI serum samples tested, 124 (25.7%) and 182 (37.8%) were IgM and IgG reactive, respectively. On multivariate analysis, IgM reactivity was associated with HIV (RR 1.66, 95%CI 1.07, 2.60; p=0.024) while IgG reactivity was associated with increasing age (p<0.001) and HIV (RR 1.93, 95%CI 1.52, 2.46; p<0.001). AFI case-patients were more likely to be IgM (p=0.002) and IgG (p<0.001) reactive compared to healthy residents. The seroincidence by HEV-specific IgM was 84.0 per 1000 person years, however, all 482 samples were negative by NAT. CONCLUSIONS Serologic evidence for HEV in Kibera suggests a high burden of infection, but NAT did not confirm HEV viremia. Additional testing is needed to determine whether EIAs are susceptible to false positivity in undifferentiated AFI populations before their widespread use.
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Affiliation(s)
- N W Furukawa
- Department of Medicine, University of Washington, Seattle, WA, USA.
| | - E H Teshale
- Division of Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - L Cosmas
- Center for Global Health, Division of Global Health Protection, Centers for Disease Control and Prevention, Nairobi, Kenya
| | - M Ochieng
- Kenya Medical Research Institute, Center for Global Health Research, Nairobi, Kenya
| | - S Gikunju
- Kenya Medical Research Institute, Center for Global Health Research, Nairobi, Kenya
| | - B S Fields
- Center for Global Health, Division of Global Health Protection, Centers for Disease Control and Prevention, Nairobi, Kenya
| | - J M Montgomery
- Center for Global Health, Division of Global Health Protection, Centers for Disease Control and Prevention, Nairobi, Kenya
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Lee K, Goodman L, Fourie C, Schenk S, Leitch B, Montgomery JM. AMPA Receptors as Therapeutic Targets for Neurological Disorders. Ion Channels as Therapeutic Targets, Part A 2016; 103:203-61. [DOI: 10.1016/bs.apcsb.2015.10.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Kay EI, Botha R, Montgomery JM, Mountjoy KG. hMRAPα, but Not hMRAP2, Enhances hMC4R Constitutive Activity in HEK293 Cells and This Is Not Dependent on hMRAPα Induced Changes in hMC4R Complex N-linked Glycosylation. PLoS One 2015; 10:e0140320. [PMID: 26469516 PMCID: PMC4607451 DOI: 10.1371/journal.pone.0140320] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 09/24/2015] [Indexed: 12/20/2022] Open
Abstract
MRAP1 but not MRAP2, is essential for melanocortin receptor 2 functional expression. Human MRAP1 splice variant (hMRAPα) and human MRAP2 (hMRAP2) also interact with the other melanocortin receptor subtypes in vitro, although the physiological significance of these interactions is unknown. Previously we showed that HA-hMC4R co-expression with hMRAPα, but not hMRAP2, specifically alters HA-hMC4R complex N-linked glycosylation. hMRAPα-FLAG also enhances hMC4R constitutive activity in vitro. Here we directly compare hMRAPα and hMRAP2 effects on hMC4R constitutive activity in HEK293 cells. In contrast to hMRAPα, co-expression with hMRAP2 had no effect on HA-hMC4R or untagged hMC4R constitutive coupling to adenylyl cyclase. We used fixed and live cell imaging of HA-hMC4R and hMC4R-eGFP respectively, to further characterise effects of hMRAPα on hMC4R subcellular trafficking. hMRAPα-FLAG co-expression did not alter the partitioning of either HA-hMC4R or hMC4R-eGFP into either the ER or the Golgi apparatus, therefore the hMRAPα effect on hMC4R complex N-linked glycosylation is probably not due to hMC4R retention in the ER. We also observed that unlike HA-hMC4R, hMC4R-eGFP lacks complex glycosylation both in the presence and absence of hMRAPα, although both HA-hMC4R and hMC4R-eGFP exhibited increased constitutive coupling to adenylyl cyclase following co-expression with hMRAPα. We conclude that hMRAPα and not hMRAP2 modulates hMC4R constitutive activity. Furthermore, hMRAPα does not increase hMC4R constitutive activity by altering hMC4R complex N-linked glycosylation. Instead we hypothesise that hMRAPα alters hMC4R conformational states leading to increased hMC4R constitutive activity.
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Affiliation(s)
- Emma I. Kay
- Department of Physiology, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
- Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Rikus Botha
- Department of Physiology, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Johanna M. Montgomery
- Department of Physiology, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
- Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Kathleen G. Mountjoy
- Department of Physiology, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
- Department of Molecular Medicine and Pathology, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
- Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
- * E-mail:
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Mao M, Montgomery JM, Kubke MF, Thorne PR. The Structural Development of the Mouse Dorsal Cochlear Nucleus. J Assoc Res Otolaryngol 2015; 16:473-86. [PMID: 25985874 DOI: 10.1007/s10162-015-0520-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 04/20/2015] [Indexed: 12/19/2022] Open
Abstract
The dorsal cochlear nucleus (DCN) is a major subdivision of the mammalian cochlear nucleus (CN) that is thought to be involved in sound localization in the vertical plane and in feature extraction of sound stimuli. The main principal cell type (pyramidal cells) integrates auditory and non-auditory inputs, which are considered to be important in performing sound localization tasks. This study aimed to investigate the histological development of the CD-1 mouse DCN, focussing on the postnatal period spanning the onset of hearing (P12). Fluorescent Nissl staining revealed that the three layers of the DCN were identifiable as early as P6 with subsequent expansion of all layers with age. Significant increases in the size of pyramidal and cartwheel cells were observed between birth and P12. Immunohistochemistry showed substantial changes in synaptic distribution during the first two postnatal weeks with subsequent maturation of the presumed mossy fibre terminals. In addition, GFAP immunolabelling identified several glial cell types in the DCN including the observation of putative tanycytes for the first time. Each glial cell type had specific spatial and temporal patterns of maturation with apparent rapid development during the first two postnatal weeks but little change thereafter. The rapid maturation of the structural organization and DCN components prior to the onset of hearing possibly reflects an influence from spontaneous activity originating in the cochlea/auditory nerve. Further refinement of these connections and development of the non-auditory connections may result from the arrival of acoustic input and experience dependent mechanisms.
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Affiliation(s)
- Miaomiao Mao
- Department of Physiology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand,
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Zheng N, Jeyifous O, Munro C, Montgomery JM, Green WN. Synaptic activity regulates AMPA receptor trafficking through different recycling pathways. eLife 2015; 4. [PMID: 25970033 PMCID: PMC4451724 DOI: 10.7554/elife.06878] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 05/13/2015] [Indexed: 12/04/2022] Open
Abstract
Changes in glutamatergic synaptic strength in brain are dependent on AMPA-type glutamate receptor (AMPAR) recycling, which is assumed to occur through a single local pathway. In this study, we present evidence that AMPAR recycling occurs through different pathways regulated by synaptic activity. Without synaptic stimulation, most AMPARs recycled in dynamin-independent endosomes containing the GTPase, Arf6. Few AMPARs recycled in dynamin-dependent endosomes labeled by transferrin receptors (TfRs). AMPAR recycling was blocked by alterations in the GTPase, TC10, which co-localized with Arf6 endosomes. TC10 mutants that reduced AMPAR recycling had no effect on increased AMPAR levels with long-term potentiation (LTP) and little effect on decreased AMPAR levels with long-term depression. However, internalized AMPAR levels in TfR-containing recycling endosomes increased after LTP, indicating increased AMPAR recycling through the dynamin-dependent pathway with synaptic plasticity. LTP-induced AMPAR endocytosis is inconsistent with local recycling as a source of increased surface receptors, suggesting AMPARs are trafficked from other sites. DOI:http://dx.doi.org/10.7554/eLife.06878.001 Cells called neurons transmit information around the brain in the form of electrical signals. At a junction between two neurons—called a synapse—an electrical signal triggers the release of small molecules called neurotransmitters. These molecules travel across the gap between the two neurons and trigger a new electrical signal in the second neuron. Memories can be stored in synapses: high levels of activity can ‘strengthen’ the synapse, which increases the transfer of information between the neurons. In many synapses, a molecule called glutamate is the neurotransmitter. Proteins called AMPARs, which are found on the surface of the neuron, can detect glutamate and transmit the signal along the second neuron. The strength of synapses is controlled by changes in AMPAR levels through ‘recycling’, where AMPAR proteins are removed from synapses, internalized and later returned to synapses. It was thought that AMPARs are recycled via just one pathway at synapses. However, the amount of recycling is much higher when the synapses are active and it is not clear how this works. Now, Zheng et al. have used fluorescent tags to track the recycling of AMPARs in synapses from rats under a microscope. The experiments show that when the synapses are not active, most AMPARs are recycled via a pathway marked by a protein called Arf6. However, when the synapses are active, most AMPAR is recycled via a different route marked by so-called ‘transferrin receptor’ proteins. The experiments also reveal that a protein called TC10 is involved in recycling AMPARs alongside Arf6, but is not required for recycling when the synapses are active and being strengthened. Unexpectedly, AMPAR internalization—via the process involving transferrin receptors—increases during synapse strengthening. This suggests that some of the extra AMPAR proteins sent to the membrane have come from other parts of the neuron away from the synapse. Zheng et al.'s findings provide evidence that AMPARs are recycled through different routes depending on the activity of the synapse. The next challenge will be to directly test whether AMPARs are transported from other parts of the neuron to the strengthened synapse and to understand how this works. DOI:http://dx.doi.org/10.7554/eLife.06878.002
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Affiliation(s)
- Ning Zheng
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Okunola Jeyifous
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Charlotte Munro
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | | | - William N Green
- Department of Neurobiology, University of Chicago, Chicago, United States
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Lee TW, Tumanov S, Villas-Bôas SG, Montgomery JM, Birch NP. Chemicals eluting from disposable plastic syringes and syringe filters alter neurite growth, axogenesis and the microtubule cytoskeleton in cultured hippocampal neurons. J Neurochem 2015; 133:53-65. [PMID: 25522164 DOI: 10.1111/jnc.13009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 11/27/2014] [Accepted: 11/28/2014] [Indexed: 12/29/2022]
Abstract
Cultures of dissociated hippocampal neurons are often used to study neuronal cell biology. We report that the development of these neurons is strongly affected by chemicals leaching from commonly used disposable medical-grade syringes and syringe filters. Contamination of culture medium by bioactive substance(s) from syringes and filters occurred with multiple manufacturing lots and filter types under normal use conditions and resulted in changes to neurite growth, axon formation and the neuronal microtubule cytoskeleton. The effects on neuronal morphology were concentration dependent and significant effects were detected even after substantial dilution of the contaminated medium. Gas chromatography-mass spectrometry analyses revealed many chemicals eluting from the syringes and filters. Three of these chemicals (stearic acid, palmitic acid and 1,2-ethanediol monoacetate) were tested but showed no effects on neurite growth. Similar changes in neuronal morphology were seen with high concentrations of bisphenol A and dibutyl phthalate, two hormonally active plasticisers. Although no such compounds were detected by gas chromatography–mass spectrometry, unknown plasticisers in leachates may affect neurites. This is the first study to show that leachates from laboratory consumables can alter the growth of cultured hippocampal neurons. We highlight important considerations to ensure leachate contamination does not compromise cell biology experiments.
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Affiliation(s)
- Tet Woo Lee
- School of Biological Sciences, University of Auckland, Auckland, New Zealand; Centre for Brain Research, University of Auckland, Auckland, New Zealand
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Abstract
Pair recordings involve simultaneous whole cell patch clamp recordings from two synaptically connected neurons, enabling not only direct electrophysiological characterization of the synaptic connections between individual neurons, but also pharmacological manipulation of either the presynaptic or the postsynaptic neuron. When carried out in organotypic hippocampal slice cultures, the probability that two neurons are synaptically connected is significantly increased. This preparation readily enables identification of cell types, and the neurons maintain their morphology and properties of synaptic function similar to that in native brain tissue. A major advantage of paired whole cell recordings is the highly precise information it can provide on the properties of synaptic transmission and plasticity that are not possible with other more crude techniques utilizing extracellular axonal stimulation. Paired whole cell recordings are often perceived as too challenging to perform. While there are challenging aspects to this technique, paired recordings can be performed by anyone trained in whole cell patch clamping provided specific hardware and methodological criteria are followed. The probability of attaining synaptically connected paired recordings significantly increases with healthy organotypic slices and stable micromanipulation allowing independent attainment of pre- and postsynaptic whole cell recordings. While CA3-CA3 pyramidal cell pairs are most widely used in the organotypic slice hippocampal preparation, this technique has also been successful in CA3-CA1 pairs and can be adapted to any neurons that are synaptically connected in the same slice preparation. In this manuscript we provide the detailed methodology and requirements for establishing this technique in any laboratory equipped for electrophysiology.
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Affiliation(s)
- Chantelle Fourie
- Department of Physiology and Centre for Brain Research, University of Auckland
| | - Marianna Kiraly
- Department of Molecular and Cellular Physiology, Stanford University
| | - Daniel V Madison
- Department of Molecular and Cellular Physiology, Stanford University
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Abstract
Human melanocortin 2 receptor accessory protein (hMRAPa) is hypothesised to have functions beyond promoting human melanocortin 2 receptor (hMC2R) functional expression. To understand these potential functions, we exogenously co-expressed hMRAPa-FLAG with each of the five hMCR subtypes in HEK293 cells and assessed hMCR subtype coupling to adenylyl cyclase. We also co-expressed each HA-hMCR subtype with hMRAPa-FLAG to investigate their subcellular localisation. hMRAPa-FLAG enhanced α-melanocyte stimulating hormone (α-MSH)-stimulated hMC1R and hMC3R but reduced NDP-α-MSH-stimulated hMC5R, maximum coupling to adenylyl cyclase. hMRAPa-FLAG specifically increased hMC4R constitutive coupling to adenylyl cyclase despite not co-localising with the HA-hMC4R in the cell membrane. hMRAPa-FLAG co-localised with HA-hMC1R or HA-hMC3R in the perinuclear region, in cytoplasmic vesicles and at the plasma membrane, while it co-localised with HA-hMC2R, HA-hMC4R and HA-hMC5R predominantly in cytoplasmic vesicles. These diverse effects of hMRAPa indicate that hMRAPa could be an important modulator of the central and peripheral melanocortin systems if hMRAPa and any hMCR subtype co-express in the same cell.
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Affiliation(s)
- Emma I Kay
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand
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Abstract
Human melanocortin 2 receptor accessory protein 1(hMRAPa) is essential for human melanocortin 2 receptor (hMC2R)-regulated adrenal steroidogenesis. hMRAPa enhances hMC2R N-linked glycosylation and maturation, promotes hMC2R cell surface expression and enables ACTH to bind and activate the MC2R. However, hMRAPa is predicted to have functions beyond its critical role in hMC2R activity. It is more widely expressed than the hMC2R and it has been shown to co-immunoprecipitate with all other hMCR subtypes and other G-protein-coupled receptors, when these are co-expressed with each receptor in heterologous cells. The physiological relevance of hMRAPa interactions with these receptors is unknown. We hypothesised that hMRAPa could influence post-translational processing and maturation of these receptors, similar to its actions on the hMC2R. Here we used co-immunoprecipitation and western blotting techniques to characterise effects of hMRAPa-FLAG co-expression on the maturation of each HA-tagged hMCR subtype and the HA-tagged human calcitonin receptor-like receptor (hCL), co-expressed in HEK293 cells. While hMRAPa-FLAG interacted with all five HA-hMCR subtypes and the HA-hCL, it only altered HA-hMC4R molecular mass. This altered HA-hMC4R molecular mass was due to a change in endoglycosidase H-resistant complex N-linked glycosylation, which we observed for HA-hMC4R in both intracellular and cell surface fractions. This effect was specific to the HA-hMC4R as hMRAPa did not alter the molecular mass of any of the other receptors that we examined. In conclusion, the specific effects of hMRAPa on hMC4R molecular mass and complex N-linked glycosylation provide evidence in support of a role for MRAPα in hMC4R functions.
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Affiliation(s)
- Emma I Kay
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand
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Fourie C, Li D, Montgomery JM. The anchoring protein SAP97 influences the trafficking and localisation of multiple membrane channels. Biochim Biophys Acta 2013; 1838:589-94. [PMID: 23535319 DOI: 10.1016/j.bbamem.2013.03.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 02/26/2013] [Accepted: 03/15/2013] [Indexed: 12/23/2022]
Abstract
SAP97 is a member of the MAGUK family of proteins that play a major role in the trafficking and targeting of membrane ion channels and cytosolic structural proteins in multiple cell types. Within neurons, SAP97 is localised throughout the secretory trafficking pathway and at the postsynaptic density (PSD). SAP97 differs from other MAGUK family members largely in its long N-terminus and in the sequences between the SH3 and GUK domains, where SAP97 undergoes significant alternative splicing to produce multiple SAP97 isoforms. These splice insertions endow SAP97 with differential cellular localisation patterns and functional roles within neurons. With regard to membrane ion channels, SAP97 forms multi-protein complexes with AMPA and NMDA-type glutamate receptors, and Kv1.4, Kv4.2, and Kir2.2 potassium channels, playing a major role in trafficking and anchoring ion channel surface expression. This highlights SAP97 not only as a regulator of neuronal excitability, synaptic function and plasticity in the brain, but also as a target for the pathophysiology of a number of neurological disorders. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.
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Affiliation(s)
- Chantelle Fourie
- Department of Physiology, University of Auckland, New Zealand; Centre for Brain Research, University of Auckland, New Zealand
| | - Dong Li
- Department of Physiology, University of Auckland, New Zealand; Centre for Brain Research, University of Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology, University of Auckland, New Zealand; Centre for Brain Research, University of Auckland, New Zealand.
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Huang LC, Barclay M, Lee K, Peter S, Housley GD, Thorne PR, Montgomery JM. Synaptic profiles during neurite extension, refinement and retraction in the developing cochlea. Neural Dev 2012; 7:38. [PMID: 23217150 PMCID: PMC3545844 DOI: 10.1186/1749-8104-7-38] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 11/26/2012] [Indexed: 12/23/2022] Open
Abstract
Background During development, excess synapses form between the central and peripheral nervous systems that are then eliminated to achieve correct connectivity. In the peripheral auditory system, the developing type I spiral ganglion afferent fibres undergo a dramatic re-organisation, initially forming connections with both sensory inner hair cells (IHCs) and outer hair cells (OHCs). The OHC connections are then selectively eliminated, leaving sparse innervation by type II afferent fibres, whilst the type I afferent synapses with IHCs are consolidated. Results We examined the molecular makeup of the synaptic contacts formed onto the IHCs and OHCs during this period of afferent fibre remodelling. We observed that presynaptic ribbons initially form at all the afferent neurite contacts, i.e. not only at the expected developing IHC-type I fibre synapses but also at OHCs where type I fibres temporarily contact. Moreover, the transient contacts forming onto OHCs possess a broad set of pre- and postsynaptic proteins, suggesting that functional synaptic connections are formed prior to the removal of type I fibre innervation. AMPA-type glutamate receptor subunits were transiently observed at the base of the OHCs, with their downregulation occurring in parallel with the withdrawal of type I fibres, dispersal of presynaptic ribbons, and downregulation of the anchoring proteins Bassoon and Shank. Conversely, at developing type I afferent IHC synapses, the presence of pre- and postsynaptic scaffold proteins was maintained, with differential plasticity in AMPA receptor subunits observed and AMPA receptor subunit composition changing around hearing onset. Conclusions Overall our data show a differential balance in the patterns of synaptic proteins at developing afferent IHC versus OHC synapses that likely reflect their stable versus transient fates.
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Affiliation(s)
- Lin-Chien Huang
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
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Park TIH, Monzo H, Mee EW, Bergin PS, Teoh HH, Montgomery JM, Faull RLM, Curtis MA, Dragunow M. Adult human brain neural progenitor cells (NPCs) and fibroblast-like cells have similar properties in vitro but only NPCs differentiate into neurons. PLoS One 2012; 7:e37742. [PMID: 22675489 PMCID: PMC3366988 DOI: 10.1371/journal.pone.0037742] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Accepted: 04/26/2012] [Indexed: 01/19/2023] Open
Abstract
The ability to culture neural progenitor cells from the adult human brain has provided an exciting opportunity to develop and test potential therapies on adult human brain cells. To achieve a reliable and reproducible adult human neural progenitor cell (AhNPC) culture system for this purpose, this study fully characterized the cellular composition of the AhNPC cultures, as well as the possible changes to this in vitro system over prolonged culture periods. We isolated cells from the neurogenic subventricular zone/hippocampus (SVZ/HP) of the adult human brain and found a heterogeneous culture population comprised of several types of post-mitotic brain cells (neurons, astrocytes, and microglia), and more importantly, two distinct mitotic cell populations; the AhNPCs, and the fibroblast-like cells (FbCs). These two populations can easily be mistaken for a single population of AhNPCs, as they both proliferate under AhNPC culture conditions, form spheres and express neural progenitor cell and early neuronal markers, all of which are characteristics of AhNPCs in vitro. However, despite these similarities under proliferating conditions, under neuronal differentiation conditions, only the AhNPCs differentiated into functional neurons and glia. Furthermore, AhNPCs showed limited proliferative capacity that resulted in their depletion from culture by 5–6 passages, while the FbCs, which appear to be from a neurovascular origin, displayed a greater proliferative capacity and dominated the long-term cultures. This gradual change in cellular composition resulted in a progressive decline in neurogenic potential without the apparent loss of self-renewal in our cultures. These results demonstrate that while AhNPCs and FbCs behave similarly under proliferative conditions, they are two different cell populations. This information is vital for the interpretation and reproducibility of AhNPC experiments and suggests an ideal time frame for conducting AhNPC-based experiments.
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Affiliation(s)
- Thomas In-Hyeup Park
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
- The Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
- Department of Anatomy and Radiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Hector Monzo
- The Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
- Department of Anatomy and Radiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Edward W. Mee
- Department of Neurosurgery, Auckland City Hospital, Auckland, New Zealand
| | - Peter S. Bergin
- Department of Neurology, Auckland City Hospital, Auckland, New Zealand
| | | | - Johanna M. Montgomery
- The Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Richard L. M. Faull
- The Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
- Department of Anatomy and Radiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Maurice A. Curtis
- The Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
- Department of Anatomy and Radiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Mike Dragunow
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
- The Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
- * E-mail:
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Lee TW, Montgomery JM, Birch NP. The serine protease inhibitor neuroserpin regulates the growth and maturation of hippocampal neurons through a non-inhibitory mechanism. J Neurochem 2012; 121:561-74. [PMID: 22191421 DOI: 10.1111/j.1471-4159.2011.07639.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Neuroserpin is a brain-specific serine protease inhibitor that is expressed in the developing and adult nervous system. Its expression profile led to suggestions that it played roles in neuronal growth and connectivity. In this study, we provide direct evidence to support a role for neuroserpin in axon and dendritic growth. We report that axon growth is enhanced while axon and dendrite diameter are reduced following neuroserpin treatment of hippocampal neurons. More complex effects are seen on dendritic growth and branching with neuroserpin-stimulating dendritic growth and branching in young neurons but switching to an inhibitory response in older neurons. The protease inhibitory activity of neuroserpin is not required to activate changes in neuronal morphology and a proportion of responses are modulated by an antagonist to the LRP1 receptor. Collectively, these findings support a key role for neuroserpin as a regulator of neuronal development through a non-inhibitory mechanism and suggest a basis for neuroserpin's effects on complex emotional behaviours and recent link to schizophrenia.
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Affiliation(s)
- Tet Woo Lee
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
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Monzo HJ, Park TI, Montgomery JM, Faull RL, Dragunow M, Curtis MA. A method for generating high-yield enriched neuronal cultures from P19 embryonal carcinoma cells. J Neurosci Methods 2012; 204:87-103. [DOI: 10.1016/j.jneumeth.2011.11.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 11/04/2011] [Accepted: 11/04/2011] [Indexed: 10/15/2022]
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Li D, Specht CG, Waites CL, Butler-Munro C, Leal-Ortiz S, Foote JW, Genoux D, Garner CC, Montgomery JM. SAP97 directs NMDA receptor spine targeting and synaptic plasticity. J Physiol 2011; 589:4491-510. [PMID: 21768261 DOI: 10.1113/jphysiol.2011.215566] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
SAP97 is a multidomain scaffold protein implicated in the forward trafficking and synaptic localization of NMDA- and AMPA-type glutamate receptors. Alternative splicing of SAP97 transcripts gives rise to palmitoylated αSAP97 and L27-domain containing βSAP97 isoforms that differentially regulate the subsynaptic localization of GluR1 subunits of AMPA receptors. Here, we examined whether SAP97 isoforms regulate the mechanisms underlying long-term potentiation (LTP) and depression (LTD) and find that both α- and β-forms of SAP97 impair LTP but enhance LTD via independent isoform-specific mechanisms. Live imaging of α- and βSAP97 revealed that the altered synaptic plasticity was not due to activity-dependent changes in SAP97 localization or exchange kinetics. However, by recording from pairs of synaptically coupled hippocampal neurons, we show that αSAP97 occludes LTP by enhancing the levels of postsynaptic AMPA receptors, while βSAP97 blocks LTP by reducing the synaptic localization of NMDA receptors. Examination of the surface pools of AMPA and NMDA receptors indicates that αSAP97 selectively regulates the synaptic pool of AMPA receptors, whereas βSAP97 regulates the extrasynaptic pools of both AMPA and NMDA receptors. Knockdown of βSAP97 increases the synaptic localization of both AMPA and NMDA receptors, showing that endogenous βSAP97 restricts glutamate receptor expression at excitatory synapses. This isoform-dependent differential regulation of synaptic versus extrasynaptic pools of glutamate receptors will determine how many receptors are available for the induction and the expression of synaptic plasticity. Our data support a model wherein SAP97 isoforms can regulate the ability of synapses to undergo plasticity by controlling the surface distribution of AMPA and NMDA receptors.
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Affiliation(s)
- Dong Li
- Centre for Brain Research and Department of Physiology, University of Auckland, New Zealand
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