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Cao X, Zhang T, Tao C, Ren Y, Wang X. A new method: Characterize and quantify biofilm wrinkles by UNet and Sholl Analysis. Biosystems 2024; 237:105131. [PMID: 38286325 DOI: 10.1016/j.biosystems.2024.105131] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/26/2024] [Accepted: 01/26/2024] [Indexed: 01/31/2024]
Abstract
The wrinkles on the biofilm contain a lot of information about biofilm growth, so it is essential to characterize and quantify these wrinkles from the original microscopic images to discover more rules governing the biofilm morphology evolution. However, the existing methods to extract the wrinkles are time-consuming, error-prone, and require manual calibration. We propose a new system: using a deep learning method - UNet to identify the biofilm wrinkles in the original experimental images, which can achieve fast and accurate extraction of wrinkles on biofilms. Combining the result of UNet and medical neuron analysis method - Sholl Analysis, we can easily characterize and quantity the B. subtilis biofilm wrinkles. We proposed new characterization parameters such as wrinkle density, wrinkle length, and wrinkle projection area, which can precisely partition the biofilm surface wrinkles into different regions from the biofilm center to the edge, different regions correspond to different growth stages. Our system can be applied to study biofilms growing in different kinds of environments and to study the biofilm growth mechanisms.
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Affiliation(s)
- Xiaolei Cao
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Tiecheng Zhang
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Cong Tao
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yifan Ren
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Xiaoling Wang
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, 100083, China; School of Engineering and Applied Sciences, Harvard University, 02138, Cambridge, MA, USA.
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Suman A, Mahapatra A, Gupta P, Ray SS, Singh RK. Polystyrene microplastics induced disturbances in neuronal arborization and dendritic spine density in mice prefrontal cortex. Chemosphere 2024; 351:141165. [PMID: 38224746 DOI: 10.1016/j.chemosphere.2024.141165] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 01/06/2024] [Accepted: 01/08/2024] [Indexed: 01/17/2024]
Abstract
An increasing use of plastics in daily life leads to the accumulation of microplastics (MPs) in the environment, posing a serious threat to the ecosystem, including humans. It has been reported that MPs cause neurotoxicity, but the deleterious effect of polystyrene (PS) MPs on neuronal cytoarchitectural morphology in the prefrontal cortex (PFC) region of mice brain remains to be established. In the present study, Swiss albino male mice were orally exposed to 0.1, 1, and 10 ppm PS-MPs for 28 days. After exposure, we found a significant accumulation of PS-MPs with a decreased number of Nissl bodies in the PFC region of the entire treated group compared to the control. Morphometric analysis in the PFC neurons using Golgi-Cox staining accompanied by Sholl analysis showed a significant reduction in basal dendritic length, dendritic intersections, nodes, and number of intersections at seventh branch order in PFC neurons of 1 ppm treated PS-MPs. In neurons of 0.1 ppm treated mice, we found only decrease in the number of intersections at the seventh branch order. While 10 ppm treated neurons decreased in basal dendritic length, dendritic intersections, followed by the number of intersections at the third and seventh branch order were observed. As well, spine density on the apical secondary branches along with mRNA level of BDNF was significantly reduced in all the PS-MPs treated PFC neurons, mainly at 1 ppm versus control. These results suggest that PS-MPs exposure affects overall basal neuronal arborization, with the highest levels at 1 and 10 ppm, followed by 0.1 ppm treated neurons, which may be related to the down-regulation of BDNF expression in PFC.
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Affiliation(s)
- Anjali Suman
- Molecular Endocrinology and Toxicology Laboratory (METLab), Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
| | - Archisman Mahapatra
- Molecular Endocrinology and Toxicology Laboratory (METLab), Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Priya Gupta
- Molecular Endocrinology and Toxicology Laboratory (METLab), Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Shubhendu Shekhar Ray
- Molecular Endocrinology and Toxicology Laboratory (METLab), Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Rahul Kumar Singh
- Molecular Endocrinology and Toxicology Laboratory (METLab), Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
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Sarkala HB, Jahanshahi M, Dolatabadi LK, Namavar MR. G-CSF improved the memory and dendritic morphology impairments in the hippocampal CA1 pyramidal neurons after brain ischemia in the male rats. Metab Brain Dis 2023; 38:2573-2581. [PMID: 37728699 DOI: 10.1007/s11011-023-01286-4] [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] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 09/01/2023] [Indexed: 09/21/2023]
Abstract
BACKGROUND Stroke remains the leading cause of death and disability in the world. A new potential treatment for stroke is the granulocyte colony-stimulating factor (G-CSF), which exerts neuroprotective effects through multiple mechanisms. Memory impairment is the most common cognitive problem after a stroke. The suggested treatment for memory impairments is cognitive rehabilitation, which is often ineffective. The hippocampus plays an important role in memory formation. This project aimed to study the effect of G-CSF on memory and dendritic morphology of hippocampal CA1 pyramidal neurons after middle cerebral artery occlusion (MCAO)in rats. METHODS Male Sprague-Dawley rats were divided into three groups: the sham, control (MCAO + Vehicle), and treatment (MCAO + G-CSF) groups. G-CSF (50 µg/kg S.C) was administered at 6, 24, and 48 h after brain ischemia induction. The passive avoidance task to evaluate learning and memory was performed on days 6 and 7 post-ischemia. Seven days after MCAO, the brain was removed and the hippocampal slices were stained with Golgi. After that, the neurons were analyzed for dendritic morphology and maturity. OUTCOMES The data showed that stroke was associated with a significant impairment in the acquisition and retention of passive avoidance tasks, while the G-CSF improved learning and memory loss. The dendritic length, arborization, spine density, and mature spines of the hippocampus CA1 neurons were significantly reduced in the control group, and treatment with G-CSF significantly increased these parameters. CONCLUSION G-CSF, even with three doses, improved learning and memory deficits, and dendritic morphological changes in the CA1 hippocampal neurons resulted from brain ischemia.
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Affiliation(s)
- Hamzeh Badeli Sarkala
- Department of Anatomical Sciences, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Anatomy, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mehrdad Jahanshahi
- Neuroscience Research Center, Department of Anatomy, Faculty of Medicine, Golestan University of Medical Sciences, Gorgan, Iran
| | - Leila Kamali Dolatabadi
- Department of Neuroscience, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran
- Alzahra Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohammad Reza Namavar
- Department of Anatomical Sciences, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
- Histomorphometry and Stereology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
- Clinical Neurology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
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Bolívar-Baquero O, Troncoso J. Facial nerve axotomy induces morphological changes in hippocampal pyramidal neurons. J Comp Neurol 2023; 531:663-680. [PMID: 36629001 DOI: 10.1002/cne.25455] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 12/01/2022] [Accepted: 12/20/2022] [Indexed: 01/12/2023]
Abstract
Facial nerve injury in rats have been widely used to study functional and structural changes that occur in the injured motoneurons and other central nervous system structures related with sensorimotor processing. A decrease in long-term potentiation of hippocampal CA3-to-CA1 commissural synapse has recently been reported related to this peripheral injury. Additionally, it has been found increased corticosterone plasmatic levels, impairment in spatial memory consolidation, and hippocampal microglial activation in animals with facial nerve axotomy. In this work, we analyzed the neuronal morphology of hippocampal CA1 and CA3 pyramidal neurons in animals with either reversible or irreversible facial nerve injury. For this purpose, brain tissues of injured animals sacrificed at different postlesion times, were stained with the Golgi-Cox method and compared with control brains. It was found that both reversible and irreversible facial nerve injury-induced significant decreases in dendritic tree complexity, dendritic length, branch points, and spine density of hippocampal neurons. However, such changes' timing varied according to hippocampal area (CA1 vs. CA3), dendritic area (apical vs. basal), and lesion type (reversible vs. irreversible). In general, the observed changes were transient when animals had the possibility of motor recovery (reversible injury), but perdurable if the recovery from the lesion was impeded (irreversible injury). CA1 apical and CA3 basal dendritic tree morphology were more sensible to irreversible injury. It is concluded that facial nerve injury induced significant changes in hippocampal CA1 and CA3 pyramidal neurons morphology, which could be related to LTP impairments and microglial activation in the hippocampal formation, previously described.
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Affiliation(s)
- Oscar Bolívar-Baquero
- Behavioral Neurophysiology Laboratory, Physiological Sciences Department, School of Medicine, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Julieta Troncoso
- Behavioral Neurophysiology Laboratory, Physiological Sciences Department, School of Medicine, Universidad Nacional de Colombia, Bogotá, Colombia.,Biology Department, School of Sciences, Universidad Nacional de Colombia, Bogotá, Colombia
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Useinovic N, Near M, Cabrera OH, Boscolo A, Milosevic A, Harvey R, Newson A, Chastain-Potts S, Quillinan N, Jevtovic-Todorovic V. Neonatal sevoflurane exposure induces long-term changes in dendritic morphology in juvenile rats and mice. Exp Biol Med (Maywood) 2023; 248:641-655. [PMID: 37309741 PMCID: PMC10350807 DOI: 10.1177/15353702231170003] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 03/11/2023] [Indexed: 06/14/2023] Open
Abstract
General anesthetics are potent neurotoxins when given during early development, causing apoptotic deletion of substantial number of neurons and persistent neurocognitive and behavioral deficits in animals and humans. The period of intense synaptogenesis coincides with the peak of susceptibility to deleterious effects of anesthetics, a phenomenon particularly pronounced in vulnerable brain regions such as subiculum. With steadily accumulating evidence confirming that clinical doses and durations of anesthetics may permanently alter the physiological trajectory of brain development, we set out to investigate the long-term consequences on dendritic morphology of subicular pyramidal neurons and expression on genes regulating the complex neural processes such as neuronal connectivity, learning, and memory. Using a well-established model of anesthetic neurotoxicity in rats and mice neonatally exposed to sevoflurane, a volatile general anesthetic commonly used in pediatric anesthesia, we report that a single 6 h of continuous anesthesia administered at postnatal day (PND) 7 resulted in lasting dysregulation in subicular mRNA levels of cAMP responsive element modulator (Crem), cAMP responsive element-binding protein 1 (Creb1), and Protein phosphatase 3 catalytic subunit alpha, a subunit of calcineurin (Ppp3ca) (calcineurin) when examined during juvenile period at PND28. Given the critical role of these genes in synaptic development and neuronal plasticity, we deployed a set of histological measurements to investigate the implications of anesthesia-induced dysregulation of gene expression on morphology and complexity of surviving subicular pyramidal neurons. Our results indicate that neonatal exposure to sevoflurane induced lasting rearrangement of subicular dendrites, resulting in higher orders of complexity and increased branching with no significant effects on the soma of pyramidal neurons. Correspondingly, changes in dendritic complexity were paralleled by the increased spine density on apical dendrites, further highlighting the scope of anesthesia-induced dysregulation of synaptic development. We conclude that neonatal sevoflurane induced persistent genetic and morphological dysregulation in juvenile rodents, which could indicate heightened susceptibility toward cognitive and behavioral disorders we are beginning to recognize as sequelae of early-in-life anesthesia.
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Affiliation(s)
- Nemanja Useinovic
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Michelle Near
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Omar Hoseá Cabrera
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Annalisa Boscolo
- Institute of Anesthesia and Intensive Care, Padua University Hospital, Padua 35128. Italy
- Department of Medicine (DIMED), University of Padua, Padua 35128, Italy
| | - Andjelko Milosevic
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Rachel Harvey
- Oakland University William Beaumont School of Medicine, Rochester, MI 48309, USA
| | - Adre Newson
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Shelby Chastain-Potts
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Nidia Quillinan
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Neuronal Injury and Plasticity Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Vesna Jevtovic-Todorovic
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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Mut-Arbona P, Huang L, Baranyi M, Tod P, Iring A, Calzaferri F, de Los Ríos C, Sperlágh B. Dual Role of the P2X7 Receptor in Dendritic Outgrowth during Physiological and Pathological Brain Development. J Neurosci 2023; 43:1125-42. [PMID: 36732073 DOI: 10.1523/JNEUROSCI.0805-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 11/11/2022] [Accepted: 11/15/2022] [Indexed: 02/04/2023] Open
Abstract
At high levels, extracellular ATP operates as a "danger" molecule under pathologic conditions through purinergic receptors, including the ionotropic P2X7 receptor (P2X7R). Its endogenous activation is associated with neurodevelopmental disorders; however, its function during early embryonic stages remains largely unclear. Our objective was to determine the role of P2X7R in the regulation of neuronal outgrowth. For this purpose, we performed Sholl analysis of dendritic branches on primary hippocampal neurons and in acute hippocampal slices from WT mice and mice with genetic deficiency or pharmacological blockade of P2X7R. Because abnormal dendritic branching is a hallmark of certain neurodevelopmental disorders, such as schizophrenia, a model of maternal immune activation (MIA)-induced schizophrenia, was used for further morphologic investigations. Subsequently, we studied MIA-induced behavioral deficits in young adult mice females and males. Genetic deficiency or pharmacological blockade of P2X7R led to branching deficits under physiological conditions. Moreover, pathologic activation of the receptor led to deficits in dendritic outgrowth on primary neurons from WT mice but not those from P2X7R KO mice exposed to MIA. Likewise, only MIA-exposed WT mice displayed schizophrenia-like behavioral and cognitive deficits. Therefore, we conclude that P2X7R has different roles in the development of hippocampal dendritic arborization under physiological and pathologic conditions.SIGNIFICANCE STATEMENT Our main finding is a novel role for P2X7R in neuronal branching in the early stages of development under physiological conditions. We show how a decrease in the expression of P2X7R during brain development causes the receptor to play pathologic roles in adulthood. Moreover, we studied a neurodevelopmental model of schizophrenia and found that, at higher ATP concentrations, endogenous activation of P2X7R is necessary and sufficient for the development of positive and cognitive symptoms.
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VONKAENEL ERIK, FEIDLER ALEXIS, LOWERY REBECCA, ANDERSH KATHERINE, LOVE TANZY, MAJEWSKA ANIA, MCCALL MATTHEWN. A Model-Based Hierarchical Bayesian Approach to Sholl Analysis. bioRxiv 2023:2023.01.23.525256. [PMID: 36747628 PMCID: PMC9900812 DOI: 10.1101/2023.01.23.525256] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Due to the link between microglial morphology and function, morphological changes in microglia are frequently used to identify pathological immune responses in the central nervous system. In the absence of pathology, microglia are responsible for maintaining homeostasis, and their morphology can be indicative of how the healthy brain behaves in the presence of external stimuli and genetic differences. Despite recent interest in high throughput methods for morphological analysis, Sholl analysis is still the gold standard for quantifying microglia morphology via imaging data. Often, the raw data are naturally hierarchical, minimally including many cells per image and many images per animal. However, existing methods for performing downstream inference on Sholl data rely on truncating this hierarchy so rudimentary statistical testing procedures can be used. To fill this longstanding gap, we introduce a fully parametric model-based approach for analyzing Sholl data. We generalize our model to a hierarchical Bayesian framework so that inference can be performed without aggressive reduction of otherwise very rich data. We apply our model to three real data examples and perform simulation studies comparing the proposed method with a popular alternative.
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Affiliation(s)
- ERIK VONKAENEL
- Department of Biostatistics and Computational Biology, University of Rochester, NY 14642, USA
| | - ALEXIS FEIDLER
- Department of Neuroscience, University of Rochester, NY 14642, USA
| | - REBECCA LOWERY
- Department of Neuroscience, University of Rochester, NY 14642, USA
| | | | - TANZY LOVE
- Department of Biostatistics and Computational Biology, University of Rochester, NY 14642, USA
| | - ANIA MAJEWSKA
- Department of Neuroscience, University of Rochester, NY 14642, USA
| | - MATTHEW N MCCALL
- Department of Biostatistics and Computational Biology, University of Rochester, NY 14642, USA
- Department of Biomedical Genetics, University of Rochester, NY 14642, USA
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Bayat AH, Azimi H, Hassani Moghaddam M, Ebrahimi V, Fathi M, Vakili K, Mahmoudiasl GR, Forouzesh M, Boroujeni ME, Nariman Z, Abbaszadeh HA, Aryan A, Aliaghaei A, Abdollahifar MA. COVID-19 causes neuronal degeneration and reduces neurogenesis in human hippocampus. Apoptosis 2022; 27:852-868. [PMID: 35876935 PMCID: PMC9310365 DOI: 10.1007/s10495-022-01754-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [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] [Accepted: 07/15/2022] [Indexed: 11/30/2022]
Abstract
Recent investigations of COVID-19 have largely focused on the effects of this novel virus on the vital organs in order to efficiently assist individuals who have recovered from the disease. In the present study we used hippocampal tissue samples extracted from people who died after COVID-19. Utilizing histological techniques to analyze glial and neuronal cells we illuminated a massive degeneration of neuronal cells and changes in glial cells morphology in hippocampal samples. The results showed that in hippocampus of the studied brains there were morphological changes in pyramidal cells, an increase in apoptosis, a drop in neurogenesis, and change in spatial distribution of neurons in the pyramidal and granular layer. It was also demonstrated that COVID-19 alter the morphological characteristics and distribution of astrocyte and microglia cells. While the exact mechanism(s) by which the virus causes neuronal loss and morphology in the central nervous system (CNS) remains to be determined, it is necessary to monitor the effect of SARS-CoV-2 infection on CNS compartments like the hippocampus in future investigations. As a result of what happened in the hippocampus secondary to COVID-19, memory impairment may be a long-term neurological complication which can be a predisposing factor for neurodegenerative disorders through neuroinflammation and oxidative stress mechanisms.
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Affiliation(s)
- Amir-Hossein Bayat
- Department of Basic Sciences, Saveh University of Medical Sciences, Saveh, Iran
| | - Helia Azimi
- Skull Base Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Meysam Hassani Moghaddam
- Department of Anatomical Sciences, Faculty of Medicine, AJA University of Medical Sciences, Tehran, Iran
| | - Vahid Ebrahimi
- Department of Anatomy and Cell Biology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mobina Fathi
- Student Research Committee, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Kimia Vakili
- Student Research Committee, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Mahdi Forouzesh
- Legal Medicine Research Center, Iranian Legal Medicine Organization, Tehran, Iran
| | - Mahdi Eskandarian Boroujeni
- Laboratory of Human Molecular Genetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - Zahra Nariman
- Skull Base Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hojjat-Allah Abbaszadeh
- Laser Application in Medical Sciences Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Arefeh Aryan
- Anatomy Department, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Abbas Aliaghaei
- Skull Base Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. .,Department of Cell Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. .,Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Mohammad-Amin Abdollahifar
- Skull Base Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. .,Department of Cell Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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9
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Abstract
P2X7 receptors regulate different aspects of neuronal development, including neurogenesis, dendritic outgrowth, and axonal elongation. Primary neuronal culture is a widely used model system in neuroscience as it enables to study molecular and cellular events caused by the activation of different ion channels, receptors, and transporters under controlled conditions. Primary neuronal cultures derived from normal and genetically modified mouse models can be used with a wide array of molecular biological, anatomical, and functional techniques such as RNA sequencing, western blots, immunostaining, Ca2+ imaging, and electrophysiology. In addition, they can also be genetically manipulated relatively easily. Moreover, cells can survive for multiple weeks if they are properly maintained and thus the development and maturation of individual neurons and their morphological properties can be studied under different conditions. Here, we present a protocol for the isolation and culturing of primary hippocampal cells from embryonic mouse hippocampal tissue (embryonic days 17.5-18.5). The neurons are plated in poly-L-lysine/laminin coated coverslips, where astroglia proliferation is controlled for the proper study of individual primary neurons. To investigate the development of dendrites and axons, as a good correlate of neuron morphology, we present a transfection protocol, which allows us to fill the whole neuron with a fluorescent protein. Subsequently, we perform tracing and analysis of dendritic branching by Sholl analysis using Neurolucida tracing Software (MBF Bioscience).
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Affiliation(s)
- Paula Mut-Arbona
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Budapest, Hungary
- János Szentágothai Doctoral School, Semmelweis University, Budapest, Hungary
| | - Beáta Sperlágh
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Budapest, Hungary.
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10
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Keil Stietz KP, Sethi S, Klocke CR, de Ruyter TE, Wilson MD, Pessah IN, Lein PJ. Sex and Genotype Modulate the Dendritic Effects of Developmental Exposure to a Human-Relevant Polychlorinated Biphenyls Mixture in the Juvenile Mouse. Front Neurosci 2021; 15:766802. [PMID: 34924936 PMCID: PMC8678536 DOI: 10.3389/fnins.2021.766802] [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: 08/30/2021] [Accepted: 11/04/2021] [Indexed: 11/23/2022] Open
Abstract
While many neurodevelopmental disorders (NDDs) are thought to result from interactions between environmental and genetic risk factors, the identification of specific gene-environment interactions that influence NDD risk remains a critical data gap. We tested the hypothesis that polychlorinated biphenyls (PCBs) interact with human mutations that alter the fidelity of neuronal Ca2+ signaling to confer NDD risk. To test this, we used three transgenic mouse lines that expressed human mutations known to alter Ca2+ signals in neurons: (1) gain-of-function mutation in ryanodine receptor-1 (T4826I-RYR1); (2) CGG-repeat expansion in the 5′ non-coding portion of the fragile X mental retardation gene 1 (FMR1); and (3) a double mutant (DM) that expressed both mutations. Transgenic and wildtype (WT) mice were exposed throughout gestation and lactation to the MARBLES PCB mix at 0.1, 1, or 6 mg/kg in the maternal diet. The MARBLES mix simulates the relative proportions of the twelve most abundant PCB congeners found in serum from pregnant women at increased risk for having a child with an NDD. Using Golgi staining, the effect of developmental PCB exposure on dendritic arborization of pyramidal neurons in the CA1 hippocampus and somatosensory cortex of male and female WT mice was compared to pyramidal neurons from transgenic mice. A multilevel linear mixed-effects model identified a main effect of dose driven by increased dendritic arborization of cortical neurons in the 1 mg/kg PCB dose group. Subsequent analyses with genotypes indicated that the MARBLES PCB mixture had no effect on the dendritic arborization of hippocampal neurons in WT mice of either sex, but significantly increased dendritic arborization of cortical neurons of WT males in the 6 mg/kg PCB dose group. Transgene expression increased sensitivity to the impact of developmental PCB exposure on dendritic arborization in a sex-, and brain region-dependent manner. In conclusion, developmental exposure to PCBs present in the gestational environment of at-risk humans interfered with normal dendritic morphogenesis in the developing mouse brain in a sex-, genotype- and brain region-dependent manner. Overall, these observations provide proof-of-principle evidence that PCBs interact with heritable mutations to modulate a neurodevelopmental outcome of relevance to NDDs.
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Affiliation(s)
- Kimberly P Keil Stietz
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Sunjay Sethi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Carolyn R Klocke
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Tryssa E de Ruyter
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Machelle D Wilson
- Clinical and Translational Science Center, Division of Biostatistics, Department of Public Health Sciences, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
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11
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Sánchez-Sarasúa S, Meseguer-Beltrán M, García-Díaz C, Beltrán-Bretones MT, ElMlili N, Sánchez-Pérez AM. IRS1 expression in hippocampus is age-dependent and is required for mature spine maintenance and neuritogenesis. Mol Cell Neurosci 2021; 118:103693. [PMID: 34942345 DOI: 10.1016/j.mcn.2021.103693] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 11/21/2022] Open
Abstract
Insulin and insulin-like growth factor type I (IGF-1) play prominent roles in brain activity throughout the lifespan. Insulin/IGF1 signaling starts with the activation of the intracellular insulin receptor substrates (IRS). In this work, we performed a comparative study of IRS1 and IRS2, together with the IGF1 (IGF1R) and insulin (IR) receptor expression in the hippocampus and prefrontal cortex during development. We found that IRS1 and IRS2 expression is prominent during development and declines in the aged hippocampus, contrary to IR, which increases in adulthood and aging. In contrast, IGF1R expression is unaffected by age. Expression patterns are similar in the prefrontal cortex. Neurite development occurs postnatally in the rodent hippocampus and cortex, and it declines in the mature and aged brain and is influenced by trophic factors. In our previous work, we demonstrated that knockdown of IRS1 by shRNA impairs learning and reduces synaptic plasticity in a rat model, as measured by synaptophysin puncta in axons. In this study, we report that shIRS1 alters spine maturation in adult hilar hippocampal neurons. Lastly, to understand the role of IRS1 in neuronal neurite tree, we transfect shIRS1 into primary neuronal cultures and observed that shIRS1 reduced neurite branching and neurite length. Our results demonstrate that IRS1/2 and insulin/IGF1 receptors display different age-dependent expression profiles and that IRS1 is required for spine maturation, demonstrating a novel role for IRS1 in synaptic plasticity.
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Campagno KE, Lu W, Jassim AH, Albalawi F, Cenaj A, Tso HY, Clark SP, Sripinun P, Gómez NM, Mitchell CH. Rapid morphologic changes to microglial cells and upregulation of mixed microglial activation state markers induced by P2X7 receptor stimulation and increased intraocular pressure. J Neuroinflammation 2021; 18:217. [PMID: 34544431 PMCID: PMC8454080 DOI: 10.1186/s12974-021-02251-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 08/25/2021] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND The identification of endogenous signals that lead to microglial activation is a key step in understanding neuroinflammatory cascades. As ATP release accompanies mechanical strain to neural tissue, and as the P2X7 receptor for ATP is expressed on microglial cells, we examined the morphological and molecular consequences of P2X7 receptor stimulation in vivo and in vitro and investigated the contribution of the P2X7 receptor in a model of increased intraocular pressure (IOP). METHODS In vivo experiments involved intravitreal injections and both transient and sustained elevation of IOP. In vitro experiments were performed on isolated mouse retinal and brain microglial cells. Morphological changes were quantified in vivo using Sholl analysis. Expression of mRNA for M1- and M2-like genes was determined with qPCR. The luciferin/luciferase assay quantified retinal ATP release while fura-2 indicated cytoplasmic calcium. Microglial migration was monitored with a Boyden chamber. RESULTS Sholl analysis of Iba1-stained cells showed retraction of microglial ramifications 1 day after injection of P2X7 receptor agonist BzATP into mouse retinae. Mean branch length of ramifications also decreased, while cell body size and expression of Nos2, Tnfa, Arg1, and Chil3 mRNA increased. BzATP induced similar morphological changes in ex vivo tissue isolated from Cx3CR1+/GFP mice, suggesting recruitment of external cells was unnecessary. Immunohistochemistry suggested primary microglial cultures expressed the P2X7 receptor, while functional expression was demonstrated with Ca2+ elevation by BzATP and block by specific antagonist A839977. BzATP induced process retraction and cell body enlargement within minutes in isolated microglial cells and increased Nos2 and Arg1. While ATP increased microglial migration, this required the P2Y12 receptor and not P2X7 receptor. Transient elevation of IOP led to microglial process retraction, cell body enlargement, and gene upregulation paralleling changes observed with BzATP injection, in addition to retinal ATP release. Pressure-dependent changes were reduced in P2X7-/- mice. Death of retinal ganglion cells accompanied increased IOP in C57Bl/6J, but not P2X7-/- mice, and neuronal loss showed some association with microglial activation. CONCLUSIONS P2X7 receptor stimulation induced rapid morphological activation of microglial cells, including process retraction and cell body enlargement, and upregulation of markers linked to both M1- and M2-type activation. Parallel responses accompanied IOP elevation, suggesting ATP release and P2X7 receptor stimulation influence the early microglial response to increased pressure.
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Affiliation(s)
- Keith E Campagno
- Department of Basic and Translational Science, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA, 19104, USA
| | - Wennan Lu
- Department of Basic and Translational Science, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA, 19104, USA
| | - Assraa Hassan Jassim
- Department of Basic and Translational Science, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA, 19104, USA
| | - Farraj Albalawi
- Department of Orthodontics, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Preventive Dental Sciences, College of Dentistry, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
- King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Aurora Cenaj
- Department of Basic and Translational Science, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA, 19104, USA
| | - Huen-Yee Tso
- Department of Basic and Translational Science, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA, 19104, USA
| | - Sophia P Clark
- Department of Basic and Translational Science, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA, 19104, USA
| | - Puttipong Sripinun
- Department of Orthodontics, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Néstor Más Gómez
- Department of Basic and Translational Science, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA, 19104, USA
| | - Claire H Mitchell
- Department of Basic and Translational Science, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA, 19104, USA.
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Department of Physiology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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13
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Sethi P, Virmani G, Gupta K, Thumu SCR, Ramanan N, Marathe S. Automated morphometric analysis with SMorph software reveals plasticity induced by antidepressant therapy in hippocampal astrocytes. J Cell Sci 2021; 134:jcs258430. [PMID: 34137444 DOI: 10.1242/jcs.258430] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 04/27/2021] [Indexed: 12/26/2022] Open
Abstract
Nervous system development and plasticity involve changes in cellular morphology, making morphological analysis a valuable exercise in the study of nervous system development, function and disease. Morphological analysis is a time-consuming exercise requiring meticulous manual tracing of cellular contours and extensions. We have developed a software tool, called SMorph, to rapidly analyze the morphology of cells of the nervous system. SMorph performs completely automated Sholl analysis. It extracts 23 morphometric features based on cell images and Sholl analysis parameters, followed by principal component analysis (PCA). SMorph was tested on neurons, astrocytes and microglia and reveals subtle changes in cell morphology. Using SMorph, we found that chronic 21-day treatment with the antidepressant desipramine results in a significant structural remodeling in hippocampal astrocytes in mice. Given the proposed involvement of astroglial structural changes and atrophy in major depression in humans, our results reveal a novel kind of structural plasticity induced by chronic antidepressant administration.
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Affiliation(s)
- Parul Sethi
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India560012
| | - Garima Virmani
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India560012
| | - Kushaan Gupta
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India560012
| | | | | | - Swananda Marathe
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India560012
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Virmani G, D'almeida P, Nandi A, Marathe S. Subfield-specific effects of chronic mild unpredictable stress on hippocampal astrocytes. Eur J Neurosci 2021; 54:5730-5746. [PMID: 33866634 DOI: 10.1111/ejn.15234] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [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: 02/07/2020] [Accepted: 04/04/2021] [Indexed: 12/20/2022]
Abstract
Major depressive disorder (MDD) is a debilitating neuropsychiatric illness affecting over 20% of the population worldwide. Despite its prevalence, our understanding of its pathophysiology is severely limited, thus hampering the development of novel therapeutic strategies. Recent advances have clearly established astrocytes as major players in the pathophysiology, and plausibly pathogenesis, of major depression. In particular, astrocyte density in the hippocampus is severely diminished in MDD patients and correlates strongly with the disease outcome. Moreover, astrocyte densities from different subfields of the hippocampus show varying trends in terms of their correlation to the disease outcome. Given the central role that hippocampus plays in the pathophysiology of depression and in the action of antidepressant drugs, changes in hippocampal astrocyte density and physiology may have a significant effect on behavioral symptoms of MDD. In this study, we used chronic mild unpredictable stress (CMUS) in mice, which induces a depressive-like state, and examined its effects on astrocytes from different subfields of the hippocampus. We used SOX9 and S100β immunostaining to estimate the number of astrocytes per square millimeter from various hippocampal subfields. Furthermore, using confocal images of fluorescently labeled glial fibrillary acidic protein (GFAP)-immunopositive hippocampal astrocytes, we quantified various morphology-related parameters and performed Sholl analysis. We found that CMUS exerts differential effects on astrocyte cell numbers, ramification, cell radius, surface area, and process width of hippocampal astrocytes from different hippocampal subfields. Taken together, our study reveals that chronic stress does not uniformly affect all hippocampal astrocytes; but exerts its effects differentially on different astrocytic subpopulations within the hippocampus.
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Affiliation(s)
- Garima Virmani
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India
| | - Priyal D'almeida
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India
| | - Arnab Nandi
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India
| | - Swananda Marathe
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India
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15
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Salesse C, Charest J, Doucet-Beaupré H, Castonguay AM, Labrecque S, De Koninck P, Lévesque M. Opposite Control of Excitatory and Inhibitory Synapse Formation by Slitrk2 and Slitrk5 on Dopamine Neurons Modulates Hyperactivity Behavior. Cell Rep 2021; 30:2374-2386.e5. [PMID: 32075770 DOI: 10.1016/j.celrep.2020.01.084] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [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: 01/08/2018] [Revised: 12/03/2019] [Accepted: 01/24/2020] [Indexed: 11/26/2022] Open
Abstract
The neurodevelopmental origin of hyperactivity disorder has been suggested to involve the dopaminergic system, but the underlying mechanisms are still unknown. Here, transcription factors Lmx1a and Lmx1b are shown to be essential for midbrain dopaminergic (mDA) neuron excitatory synaptic inputs and dendritic development. Strikingly, conditional knockout (cKO) of Lmx1a/b in postmitotic mDA neurons results in marked hyperactivity. In seeking Lmx1a/b target genes, we identify positively regulated Slitrk2 and negatively regulated Slitrk5. These two synaptic adhesion proteins promote excitatory and inhibitory synapses on mDA neurons, respectively. Knocking down Slitrk2 reproduces some of the Lmx1a/b cKO cellular and behavioral phenotypes, whereas Slitrk5 knockdown has opposite effects. The hyperactivity caused by this imbalance in excitatory/inhibitory synaptic inputs on dopamine neurons is reproduced by chronically inhibiting the ventral tegmental area during development using pharmacogenetics. Our study shows that alterations in developing dopaminergic circuits strongly impact locomotor activity, shedding light on mechanisms causing hyperactivity behaviors.
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Affiliation(s)
- Charleen Salesse
- CERVO Brain Research Centre, 2601 de la Canardière, Québec, QC G1J 2G3, Canada
| | - Julien Charest
- CERVO Brain Research Centre, 2601 de la Canardière, Québec, QC G1J 2G3, Canada
| | | | | | - Simon Labrecque
- CERVO Brain Research Centre, 2601 de la Canardière, Québec, QC G1J 2G3, Canada
| | - Paul De Koninck
- CERVO Brain Research Centre, 2601 de la Canardière, Québec, QC G1J 2G3, Canada; Department of Biochemistry, Microbiology and Bioinformatics, Faculty of Science and Engineering, Université Laval, Québec, QC G1V 0A6, Canada
| | - Martin Lévesque
- CERVO Brain Research Centre, 2601 de la Canardière, Québec, QC G1J 2G3, Canada; Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec, QC G1V 0A6, Canada.
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Yajima H, Amano I, Ishii S, Sadakata T, Miyazaki W, Takatsuru Y, Koibuchi N. Absence of Thyroid Hormone Induced Delayed Dendritic Arborization in Mouse Primary Hippocampal Neurons Through Insufficient Expression of Brain-Derived Neurotrophic Factor. Front Endocrinol (Lausanne) 2021; 12:629100. [PMID: 33708176 PMCID: PMC7940752 DOI: 10.3389/fendo.2021.629100] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 01/06/2021] [Indexed: 12/22/2022] Open
Abstract
Thyroid hormone (TH) plays important roles in the developing brain. TH deficiency in early life leads to severe developmental impairment in the hippocampus. However, the mechanisms of TH action in the developing hippocampus are still largely unknown. In this study, we generated 3,5,3'-tri-iodo-l-thyronine (T3)-free neuronal supplement, based on the composition of neuronal supplement 21 (NS21), to examine the effect of TH in the developing hippocampus using primary cultured neurons. Effects of TH on neurons were compared between cultures in this T3-free culture medium (-T3 group) and a medium in which T3 was added (+T3 group). Morphometric analysis and RT-qPCR were performed on 7, 10, and 14 days in vitro (DIV). On 10 DIV, a decreased dendrite arborization in -T3 group was observed. Such difference was not observed on 7 and 14 DIV. Brain-derived neurotrophic factor (Bdnf) mRNA levels also decreased significantly in -T3 group on 10 DIV. We then confirmed protein levels of phosphorylated neurotrophic tyrosine kinase type 2 (NTRK2, TRKB), which is a receptor for BDNF, on 10 DIV by immunocytochemistry and Western blot analysis. Phosphorylated NTRK2 levels significantly decreased in -T3 group compared to +T3 group on 10 DIV. Considering the role of BDNF on neurodevelopment, we examined its involvement by adding BDNF on 8 and 9 DIV. Addition of 10 ng/ml BDNF recovered the suppressed dendrite arborization induced by T3 deficiency on 10 DIV. We show that the lack of TH induces a developmental delay in primary hippocampal neurons, likely caused through a decreased Bdnf expression. Thus, BDNF may play a role in TH-regulated dendritogenesis.
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Affiliation(s)
- Hiroyuki Yajima
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Izuki Amano
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Sumiyasu Ishii
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Tetsushi Sadakata
- Education and Research Support Center, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Wataru Miyazaki
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Maebashi, Japan
- Department of Bioscience and Laboratory Medicine, Hirosaki University Graduate School of Health Sciences, Hirosaki, Japan
| | - Yusuke Takatsuru
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Maebashi, Japan
- Department of Medicine, Johmoh Hospital, Maebashi, Japan
- Department of Nutrition and Health Sciences, Toyo University, Itakura, Japan
| | - Noriyuki Koibuchi
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Maebashi, Japan
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17
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Abstract
Several studies are available addressing the mechanisms of vascular morphogenesis in order to unravel how cooperative cell behavior can follow from the underlying, genetically regulated behavior of endothelial cells and from cell-to-cell and cell-to-extracellular matrix interactions. From the morphological standpoint several aspects of the process are of interest. They include the way the pattern of vessels fills the available tissue space and how the network grows during the angiogenic process, namely how a main trunk divides into smaller branches, and how branching occurs at different distances from the root point of a vascular tree. A third morphological aspect of interest concerns the spatial relationship between vessels and tissue cells able to secrete factors modulating endothelial cells self-organization, thus influencing vascular rearrangement.In the present chapter image analysis methods allowing for a quantitative characterization of these morphological aspects will be detailed and discussed. They are almost based on concepts derived from the theoretical framework represented by spatial statistics.
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Affiliation(s)
- Diego Guidolin
- Section of Anatomy, Department of Neuroscience, University of Padova Medical School, Padova, Italy.
| | - Cinzia Tortorella
- Section of Anatomy, Department of Neuroscience, University of Padova Medical School, Padova, Italy
| | - Domenico Ribatti
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs, University of Bari Medical School, Bari, Italy
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18
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Bevan RJ, Hughes TR, Williams PA, Good MA, Morgan BP, Morgan JE. Retinal ganglion cell degeneration correlates with hippocampal spine loss in experimental Alzheimer's disease. Acta Neuropathol Commun 2020; 8:216. [PMID: 33287900 PMCID: PMC7720390 DOI: 10.1186/s40478-020-01094-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 11/23/2020] [Indexed: 02/06/2023] Open
Abstract
Neuronal dendritic and synaptic pruning are early features of neurodegenerative diseases, including Alzheimer’s disease. In addition to brain pathology, amyloid plaque deposition, microglial activation, and cell loss occur in the retinas of human patients and animal models of Alzheimer’s disease. Retinal ganglion cells, the output neurons of the retina, are vulnerable to damage in neurodegenerative diseases and are a potential opportunity for non-invasive clinical diagnosis and monitoring of Alzheimer’s progression. However, the extent of retinal involvement in Alzheimer’s models and how well this reflects brain pathology is unclear. Here we have quantified changes in retinal ganglion cells dendritic structure and hippocampal dendritic spines in three well-studied Alzheimer’s mouse models, Tg2576, 3xTg-AD and APPNL-G-F. Dendritic complexity of DiOlistically labelled retinal ganglion cells from retinal explants was reduced in all three models in an age-, gender-, and receptive field-dependent manner. DiOlistically labelled hippocampal slices showed spine loss in CA1 apical dendrites in all three Alzheimer’s models, mirroring the early stages of neurodegeneration as seen in the retina. Morphological classification showed that loss of thin spines predominated in all. The demonstration that retinal ganglion cells dendritic field reduction occurs in parallel with hippocampal dendritic spine loss in all three Alzheimer’s models provide compelling support for the use of retinal neurodegeneration. As retinal dendritic changes are within the optical range of current clinical imaging systems (for example optical coherence tomography), our study makes a case for imaging the retina as a non-invasive way to diagnose disease and monitor progression in Alzheimer’s disease.
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Abstract
Sholl analysis has been an important technique in dendritic anatomy for more than 60 years. The Sholl intersection profile is obtained by counting the number of dendritic branches at a given distance from the soma and is a key measure of dendritic complexity; it has applications from evaluating the changes in structure induced by pathologies to estimating the expected number of anatomical synaptic contacts. We find that the Sholl intersection profiles of most neurons can be reproduced from three basic, functional measures: the domain spanned by the dendritic arbor, the total length of the dendrite, and the angular distribution of how far dendritic segments deviate from a direct path to the soma (i.e., the root angle distribution). The first two measures are determined by axon location and hence microcircuit structure; the third arises from optimal wiring and represents a branching statistic estimating the need for conduction speed in a neuron.
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Affiliation(s)
- Alex D Bird
- Frankfurt Institute for Advanced Studies, Frankfurt-am-Main 60438, Germany; Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Frankfurt-am-Main 60528, Germany.
| | - Hermann Cuntz
- Frankfurt Institute for Advanced Studies, Frankfurt-am-Main 60438, Germany; Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Frankfurt-am-Main 60528, Germany
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20
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Schmuck MR, Keil KP, Sethi S, Morgan RK, Lein PJ. Automated high content image analysis of dendritic arborization in primary mouse hippocampal and rat cortical neurons in culture. J Neurosci Methods 2020; 341:108793. [PMID: 32461071 PMCID: PMC7357201 DOI: 10.1016/j.jneumeth.2020.108793] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 04/17/2020] [Accepted: 05/18/2020] [Indexed: 01/28/2023]
Abstract
BACKGROUND Primary neuronal cell cultures are useful for studying mechanisms that influence dendritic morphology during normal development and in response to various stressors. However, analyzing dendritic morphology is challenging, particularly in cultures with high cell density, and manual methods of selecting neurons and tracing dendritic arbors can introduce significant bias, and are labor-intensive. To overcome these challenges, semi-automated and automated methods are being developed, with most software solutions requiring computer-assisted dendrite tracing with subsequent quantification of various parameters of dendritic morphology, such as Sholl analysis. However fully automated approaches for classic Sholl analysis of dendritic complexity are not currently available. NEW METHOD The previously described Omnisphero software, was extended by adding new functions to automatically assess dendritic mass, total length of the dendritic arbor and the number of primary dendrites, branch points, and terminal tips, and to perform Sholl analysis. RESULTS The new functions for assessing dendritic morphology were validated using primary mouse hippocampal and rat cortical neurons transfected with a fluorescently tagged MAP2 cDNA construct. These functions allow users to select specific populations of neurons as a training set for subsequent automated selection of labeled neurons in high-density cultures. COMPARISON WITH EXISTING SEMI-AUTOMATED METHODS Compared to manual or semi-automated analyses of dendritic arborization, the new functions increase throughput while significantly decreasing researcher bias associated with neuron selection, tracing, and thresholding. CONCLUSION These results demonstrate the importance of using unbiased automated methods to mitigate experimenter-dependent bias in analyzing dendritic morphology.
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Affiliation(s)
- Martin R Schmuck
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
| | - Kimberly P Keil
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
| | - Sunjay Sethi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
| | - Rhianna K Morgan
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
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Ratliff WA, Delic V, Pick CG, Citron BA. Dendritic arbor complexity and spine density changes after repetitive mild traumatic brain injury and neuroprotective treatments. Brain Res 2020; 1746:147019. [PMID: 32681835 DOI: 10.1016/j.brainres.2020.147019] [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] [Received: 05/16/2020] [Revised: 06/25/2020] [Accepted: 07/10/2020] [Indexed: 12/17/2022]
Abstract
Traumatic brain injury has been described as the signature affliction of recent military conflicts and repetitive TBIs, particularly associated with military and athletic activities, typically result in more severe clinical effects. The majority of TBIs are mild, but they can result in long term cognitive deficits for which there is no effective treatment. One of the most significant deficits observed in TBI patients is memory loss, which suggests that TBI can induce pathological changes within the hippocampus. tert-butylhydroquinone (tBHQ) and pioglitazone activate the Nrf2 and PPAR-γ transcription factors, respectively, and both have been shown to be neuroprotective in model systems. We examined the morphological changes within the hippocampus following repetitive mild TBI and simultaneous treatment with both factors. We utilized a closed head injury mouse model with five injuries over 5 weeks. Our results showed marked morphological changes among the dendrites and dendritic spines of the neurons of the dentate gyrus of the hippocampus. We observed decreases in overall dendritic length, as well as in the quantity and density of dendritic spines. Our treatment partially ameliorated these effects, suggesting that the Nrf2 and PPAR-γ transcription factors may be important targets for future drug development in the treatment of TBI in humans.
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Affiliation(s)
- Whitney A Ratliff
- Laboratory of Molecular Biology, Bay Pines VA Healthcare System, Research and Development 151, Bldg. 22 Rm. 123, 10000 Bay Pines Blvd, Bay Pines, FL 33744, United States
| | - Vedad Delic
- Laboratory of Molecular Biology, VA New Jersey Health Care System, Research & Development (15), Bldg. 16, Rm 16-176 385 Tremont Ave, East Orange, NJ 07018, United States
| | - Chaim G Pick
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel; Dr. Miriam and Sheldon G. Adelson Chair and Center for the Biology of Addictive Diseases, Tel Aviv University, Tel Aviv, Israel
| | - Bruce A Citron
- Laboratory of Molecular Biology, VA New Jersey Health Care System, Research & Development (15), Bldg. 16, Rm 16-176 385 Tremont Ave, East Orange, NJ 07018, United States; Laboratory of Molecular Biology, Bay Pines VA Healthcare System, Research and Development 151, Bldg. 22 Rm. 123, 10000 Bay Pines Blvd, Bay Pines, FL 33744, United States; Department of Pharmacology, Physiology & Neuroscience, Rutgers-New Jersey Medical School, Newark, NJ 07103, United States.
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López-Cabrera JD, Hernández-Pérez LA, Orozco-Morales R, Lorenzo-Ginori JV. New morphological features based on the Sholl analysis for automatic classification of traced neurons. J Neurosci Methods 2020; 343:108835. [PMID: 32615140 DOI: 10.1016/j.jneumeth.2020.108835] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/29/2020] [Accepted: 06/26/2020] [Indexed: 11/17/2022]
Abstract
BACKGROUND This article addresses the automatic classification of reconstructed neurons through their morphological features. The purpose was to extend the capabilities of the L-Measure software. METHODS New morphological features were developed, based on modifications of the conventional Sholl analysis. The lengths of the compartments, as well as their volumes, were added to the features used in the classical analysis in order to improve the results during automatic neuron classification. FSM were used to obtain subsets of lower cardinality from the full feature sets and the usefulness of these subsets was tested through their use in supervised classification tasks. The study was based on two types of neurons belonging to mice: pyramidal and GABAergic interneurons. Furthermore, a set of pyramidal neurons belonging to Later 4 and Layer 5 was analyzed. RESULTS RF classifier shown the best performance combined with a Wrapper method.U-WNAD set allowed to obtain higher values than WN, A and D in all cases and better results than LM for the filters and wrappers FSM. U-LM-WNAD set, led to the highest AUC values for all the FSM studied. Similar results for different regions of cortex were obtained. Comparison with Existing Methods The new features exhibited high discriminatory power with which the values of AUC and Acc obtained in the experiments exceeded those obtained using only the features provided by L-Measure. CONCLUSIONS The highest values of AUC and Acc were obtained from the sets U-WNAD and U-LM-WNAD, evidencing the discriminatory power of the new proposed features.
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Affiliation(s)
- José D López-Cabrera
- Centro de Investigaciones de la Informática, Universidad Central "Marta Abreu" de Las Villas, Santa Clara, CP 54830, Cuba.
| | | | - Rubén Orozco-Morales
- Departmento de Automática y Sistemas Computacionales, Universidad Central "Marta Abreu" de Las Villas, Santa Clara, Cuba
| | - Juan V Lorenzo-Ginori
- Centro de Investigaciones de la Informática, Universidad Central "Marta Abreu" de Las Villas, Santa Clara, CP 54830, Cuba
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Abstract
Astrocytes have a high impact on the structure of the central nervous system, as they control neural activity, development, and plasticity. Heterogeneity of astrocytes has been shown before, but so far only a few studies have demonstrated heterogeneous morphology of astrocytes concerning aging. In this study, we examined morphologic differences of astrocyte subpopulations in adult mice and the progression of these differences with age. We surveyed astrocytes in olfactory bulb slices of mice aged 3 months, 1 year and 2 years (three animals each age group), based on their appearance in anti-GFAP immunostaining. Based on this data we established three different types of astrocytes: type I (stellate), type II (elliptic), and type III (squid-like). We found that with the advanced age of the mice, astrocytes grow in size and complexity. Major changes occurred between the ages of 3 months and 1 year, while between 1 and 2 years no significant development in cell size and complexity could be detected. Our results show that astrocytes in the olfactory bulb are heterogeneous and undergo morphological transformation until late adolescence but not upon senescence. Structural plasticity is further substantiated by the expression of vimentin in some astrocyte processes in all age groups.
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Affiliation(s)
- Marcel Klein
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Christian Lohr
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Damian Droste
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
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Hawlitschka A, Berg C, Schmitt O, Holzmann C, Wree A, Antipova V. Repeated intrastriatal application of botulinum neurotoxin-A did not influence choline acetyltransferase-immunoreactive interneurons in hemiparkinsonian rat brain - A histological, stereological and correlational analysis. Brain Res 2020; 1742:146877. [PMID: 32387181 DOI: 10.1016/j.brainres.2020.146877] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 04/06/2020] [Accepted: 05/05/2020] [Indexed: 12/29/2022]
Abstract
In Parkinson's disease, dopamine depletion leads to hyperactivity of cholinergic interneurons in the caudate-putamen (CPu). Botulinum neurotoxin-A (BoNT-A) inhibits the release of acetylcholine in the peripheral nervous system and is also thought to act as a local anticholinergic drug when injected intrastriatally. In hemiparkinsonian (hemi-PD) rats, a unilateral intrastriatal injection of 1 ng BoNT-A significantly diminished apomorphine-induced rotation behavior for at least 3 months, the effect fading thereafter. A second intrastriatal BoNT-A application, 6 months after the first one, led to a stronger and longer-lasting, beneficial behavioral reaction. As a single BoNT-A injection was not cytotoxic in the rat striatum and resembled BoNT-A treatment in clinical practice, here, we investigated the structural outcome of repeated intrastriatal BoNT-A injections with respect to striatal volume, the number of choline acetyltransferase-immunoreactive (ChAT-ir) interneurons and of the length of their dendritic arbors, and the numeric density of ChAT-ir BoNT-A-induced varicosities (BiVs). Repeated unilateral intrastriatal BoNT-A application decreased the volume of the injected CPu, but did not significantly change the number of striatal ChAT-ir interneurons. Also, the total dendrite length of ChAT-ir interneurons after repeated BoNT-A application resembled the values in double vehicle-injected hemi-PD rats. In repeatedly BoNT-A-injected hemi-PD rats, the numeric density of ChAT-ir BiVs in the CPu was increased compared with rats only intrastriatally injected once with BoNT-A. Even repeated BoNT-A injections in rat striata did not cause substantial morphological changes in ChAT-ir neuron, except for the increased numeric density of ChAT-ir BiVs.
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25
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Iaboni DSM, Farrell SR, Chauhan BC. Morphological multivariate cluster analysis of murine retinal ganglion cells selectively expressing yellow fluorescent protein. Exp Eye Res 2020; 196:108044. [PMID: 32376469 DOI: 10.1016/j.exer.2020.108044] [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] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/10/2020] [Accepted: 04/25/2020] [Indexed: 10/24/2022]
Abstract
Optic neuropathies, such as glaucoma, lead to retinal ganglion cell (RGC) death. Transgenic mouse strains that express fluorescent proteins under the control of the Thy1 promoter have permitted single RGC imaging. Specifically, in one strain of mice expressing yellow fluorescent protein (Thy1-YFP), fluorescence is expressed in only 0.2% of RGCs. This reduced expression allows visualization of the full dendritic arbour of YFP-expressing RGCs, facilitating the investigation of structural changes. As susceptibility amongst RGCs varies with morphology and subtype, labelling methods should ideally non-discriminately label RGCs to accurately determine the effects of experimental glaucoma. This study therefore sought to determine morphological subtypes of RGCs in the Thy1-YFP mouse strain. Retinas from Thy1-YFP mice were imaged ex vivo with fluorescence microscopy. With Sholl analysis, a technique for quantifying the morphology of individual neurons, the dendritic field (DF), area under the curve (AUC), normalized AUC (Nav), peak number of intersections (PNI), and skew for single RGCs were computed. The distance of the RGC from the optic nerve head (dONH) was also measured. These morphological parameters were inputted into a multivariate cluster analysis to determine the optimal number of clusters to group all RGCs analyzed, which were then grouped into "Small", "Medium", and "Large" sized cluster groups according to increasing DF size. A total of 178 RGCs from 10 retinas of 8 mice were analyzed from which the cluster analysis identified 13 clusters. Eighty-eight (49%), 77 (43.2%), and 13 (7.3%) RGCs were grouped into small, medium and large clusters, respectively. Clusters 1-6 had small DFs. Clusters 1 and 3 had the lowest AUC and Nav. Clusters 2, 3, and 5 had asymmetric DFs while Clusters 3, 5, and 6 were distal to the ONH. Clusters 7-11 had medium DFs; of these, Clusters 7 and 10 had the lowest AUC, Clusters 8 and 10 had the highest skew, and Clusters 7 and 11 were closest to the ONH. Clusters 12 and 13 had large DFs. Both had low skew and high AUC. High PNI and dONH distinguished Cluster 12 from Cluster 13. We present the largest study to date examining YFP expression in RGCs of transgenic Thy1-YFP mice. Among the 13 clusters, there was a wide range of morphological features with further variation within size categories. Our findings support the notion that YFP is expressed non-discriminatingly in RGCs of Thy1-YFP transgenic mice and this strain is a valuable tool for studies of experimental optic neuropathies.
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Affiliation(s)
- Douglas S M Iaboni
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Sir Charles Tupper Medical Building 5850 College Street, B3H 4R2, Halifax, Nova Scotia, Canada; Dalhousie Medical School, Faculty of Medicine, Dalhousie University, Sir Charles Tupper Medical Building 5850 College Street, B3H 4R2, Halifax, Nova Scotia, Canada
| | - Spring R Farrell
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Sir Charles Tupper Medical Building 5850 College Street, B3H 4R2, Halifax, Nova Scotia, Canada; Department of Medical Neuroscience, Dalhousie University, Sir Charles Tupper Medical Building 5850 College Street, B3H 4R2, Halifax, Nova Scotia, Canada; Nova Scotia Health Authority, 1276 South Park Street, 2W Victoria, B3H 2Y9, Halifax, Nova Scotia, Canada
| | - Balwantray C Chauhan
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Sir Charles Tupper Medical Building 5850 College Street, B3H 4R2, Halifax, Nova Scotia, Canada; Department of Medical Neuroscience, Dalhousie University, Sir Charles Tupper Medical Building 5850 College Street, B3H 4R2, Halifax, Nova Scotia, Canada; Nova Scotia Health Authority, 1276 South Park Street, 2W Victoria, B3H 2Y9, Halifax, Nova Scotia, Canada; Department of Physiology and Biophysics, Dalhousie University, Sir Charles Tupper Medical Building 5850 College Street, B3H 4R2, Halifax, Nova Scotia, Canada; Department of Ophthalmology and Visual Sciences, Dalhousie University, 1276 South Park Street, 2W Victoria, B3H 2Y9, Halifax, Nova Scotia, Canada.
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26
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Srinivasan A, Srinivasan A, Ferland RJ. AutoSholl allows for automation of Sholl analysis independent of user tracing. J Neurosci Methods 2019; 331:108529. [PMID: 31760060 DOI: 10.1016/j.jneumeth.2019.108529] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [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: 08/15/2019] [Revised: 11/20/2019] [Accepted: 11/20/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND Sholl analysis has been used to analyze neuronal morphometry and dendritic branching and complexity for many years. While the process has become semi-automated in recent years, existing software packages are still dependent on user tracing and hence are subject to observer bias, variability, and increased user times for analyses. Commercial software packages have the same issues as they also rely on user tracing. In addition, these packages are also expensive and require extensive user training. NEW METHOD To address these issues, we have developed a broadly applicable, no-cost ImageJ plugin, we call AutoSholl, to perform Sholl analysis on pre-processed and 'thresholded' images. This algorithm extends the already existing plugin in Fiji ImageJ for Sholl analysis by allowing for secondary analysis techniques, such as determining number and length of root, intermediate, and terminal dendrites; functions not currently supported in the existing Sholl Analysis plugin in Fiji ImageJ. RESULTS The algorithm allows for rapid Sholl analysis in both 2-dimensional and 3-dimensional data sets independent of user tracing. COMPARISON WITH EXISTING METHODS We validated the performance of AutoSholl against pre-existing software packages using trained human observers and images of neurons. We found that our algorithm outputs similar results as available software (i.e., Bonfire), but allows for faster analysis times and unbiased quantification. CONCLUSIONS As such, AutoSholl allows inexperienced observers to output results like more trained observers efficiently, thereby increasing the consistency, speed, and reliability of Sholl analyses.
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Affiliation(s)
- Aditya Srinivasan
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, USA.
| | | | - Russell J Ferland
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, USA; Department of Neurology, Albany Medical College, Albany, NY 12208, USA; Department of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, ME 04005, USA.
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Gzielo K, Soltys Z, Rajfur Z, Setkowicz ZK. The Impact of the Ketogenic Diet on Glial Cells Morphology. A Quantitative Morphological Analysis. Neuroscience 2019; 413:239-251. [PMID: 31220541 DOI: 10.1016/j.neuroscience.2019.06.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [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: 02/04/2019] [Revised: 06/06/2019] [Accepted: 06/07/2019] [Indexed: 12/14/2022]
Abstract
Ketogenic diet is reported to protect against cognitive decline, drug-resistant epilepsy, Alzheimer's Disease, damaging effect of ischemic stroke and many neurological diseases. Despite mounting evidence that this dietary treatment works, the exact mechanism of its protective activity is largely unknown. Ketogenic diet acts systemically, not only changing GABA signaling in neurons, but also influencing the reliance on mitochondrial respiration, known to be disrupted in many neurological diseases. Normally, human body is driven by glucose while ketogenic diet mimics starvation and energy required for proper functioning comes from fatty acids oxidation. In the brain astrocytes are believed to be the sole neural cells capable of fatty oxidation. Here we try to explain that not exclusively neurons, but also morphological changes of astroglia and/or microglia due to different metabolic state are important for the mechanism underlying the protective role of ketogenic diet. By quantifying different parameters describing cellular morphology like ramification index or fractal dimension and using Principal Component Analysis to discover the regularities between them, we demonstrate that in normal adult rat brain, ketogenic diet itself is able to change glial morphology, indicating an important role of these underappreciated cells in the brain metabolism.
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Affiliation(s)
- K Gzielo
- Department of Neuroanatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland.
| | - Z Soltys
- Department of Neuroanatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Z Rajfur
- Institute of Physics, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Krakow, Poland
| | - Z K Setkowicz
- Department of Neuroanatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
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28
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Haslinger D, Waltes R, Yousaf A, Lindlar S, Schneider I, Lim CK, Tsai MM, Garvalov BK, Acker-Palmer A, Krezdorn N, Rotter B, Acker T, Guillemin GJ, Fulda S, Freitag CM, Chiocchetti AG. Loss of the Chr16p11.2 ASD candidate gene QPRT leads to aberrant neuronal differentiation in the SH-SY5Y neuronal cell model. Mol Autism 2018; 9:56. [PMID: 30443311 PMCID: PMC6220561 DOI: 10.1186/s13229-018-0239-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [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: 05/02/2018] [Accepted: 10/15/2018] [Indexed: 12/19/2022] Open
Abstract
Background Altered neuronal development is discussed as the underlying pathogenic mechanism of autism spectrum disorders (ASD). Copy number variations of 16p11.2 have recurrently been identified in individuals with ASD. Of the 29 genes within this region, quinolinate phosphoribosyltransferase (QPRT) showed the strongest regulation during neuronal differentiation of SH-SY5Y neuroblastoma cells. We hypothesized a causal relation between this tryptophan metabolism-related enzyme and neuronal differentiation. We thus analyzed the effect of QPRT on the differentiation of SH-SY5Y and specifically focused on neuronal morphology, metabolites of the tryptophan pathway, and the neurodevelopmental transcriptome. Methods The gene dosage-dependent change of QPRT expression following Chr16p11.2 deletion was investigated in a lymphoblastoid cell line (LCL) of a deletion carrier and compared to his non-carrier parents. Expression of QPRT was tested for correlation with neuromorphology in SH-SY5Y cells. QPRT function was inhibited in SH-SY5Y neuroblastoma cells using (i) siRNA knockdown (KD), (ii) chemical mimicking of loss of QPRT, and (iii) complete CRISPR/Cas9-mediated knock out (KO). QPRT-KD cells underwent morphological analysis. Chemically inhibited and QPRT-KO cells were characterized using viability assays. Additionally, QPRT-KO cells underwent metabolite and whole transcriptome analyses. Genes differentially expressed upon KO of QPRT were tested for enrichment in biological processes and co-regulated gene-networks of the human brain. Results QPRT expression was reduced in the LCL of the deletion carrier and significantly correlated with the neuritic complexity of SH-SY5Y. The reduction of QPRT altered neuronal morphology of differentiated SH-SY5Y cells. Chemical inhibition as well as complete KO of the gene were lethal upon induction of neuronal differentiation, but not proliferation. The QPRT-associated tryptophan pathway was not affected by KO. At the transcriptome level, genes linked to neurodevelopmental processes and synaptic structures were affected. Differentially regulated genes were enriched for ASD candidates, and co-regulated gene networks were implicated in the development of the dorsolateral prefrontal cortex, the hippocampus, and the amygdala. Conclusions In this study, QPRT was causally related to in vitro neuronal differentiation of SH-SY5Y cells and affected the regulation of genes and gene networks previously implicated in ASD. Thus, our data suggest that QPRT may play an important role in the pathogenesis of ASD in Chr16p11.2 deletion carriers.
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Affiliation(s)
- Denise Haslinger
- 1Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Frankfurt, JW Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Regina Waltes
- 1Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Frankfurt, JW Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Afsheen Yousaf
- 1Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Frankfurt, JW Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Silvia Lindlar
- 1Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Frankfurt, JW Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Ines Schneider
- Institute of Experimental Cancer Research in Pediatrics, Frankfurt am Main, Germany
| | - Chai K Lim
- 3Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales Australia
| | - Meng-Miao Tsai
- 4Neuropathology, University of Giessen, Giessen, Germany
| | - Boyan K Garvalov
- 4Neuropathology, University of Giessen, Giessen, Germany.,5Department of Microvascular Biology and Pathobiology, European Center for Angioscience (ECAS), Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Amparo Acker-Palmer
- 6Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences (BMLS), JW Goethe University of Frankfurt, Frankfurt am Main, Germany
| | | | | | - Till Acker
- 4Neuropathology, University of Giessen, Giessen, Germany
| | - Gilles J Guillemin
- 3Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales Australia
| | - Simone Fulda
- Institute of Experimental Cancer Research in Pediatrics, Frankfurt am Main, Germany
| | - Christine M Freitag
- 1Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Frankfurt, JW Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Andreas G Chiocchetti
- 1Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Frankfurt, JW Goethe University Frankfurt, Frankfurt am Main, Germany
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29
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Keil KP, Miller GW, Chen H, Sethi S, Schmuck MR, Dhakal K, Kim JW, Lein PJ. PCB 95 promotes dendritic growth in primary rat hippocampal neurons via mTOR-dependent mechanisms. Arch Toxicol 2018; 92:3163-73. [PMID: 30132043 DOI: 10.1007/s00204-018-2285-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 08/06/2018] [Indexed: 01/28/2023]
Abstract
Polychlorinated biphenyls (PCBs), and in particular non-dioxin-like (NDL) congeners, continue to pose a significant risk to the developing nervous system. PCB 95, a prevalent NDL congener in the human chemosphere, promotes dendritic growth in rodent primary neurons by activating calcium-dependent transcriptional mechanisms that normally function to link activity to dendritic growth. Activity-dependent dendritic growth is also mediated by calcium-dependent translational mechanisms involving mechanistic target of rapamycin (mTOR), suggesting that the dendrite-promoting activity of PCB 95 may also involve mTOR signaling. Here, we test this hypothesis using primary neuron-glia co-cultures derived from the hippocampi of postnatal day 0 Sprague Dawley rats. PCB 95 (1 nM) activated mTOR in hippocampal cultures as evidenced by increased phosphorylation of mTOR at ser2448. Pharmacologic inhibition of mTOR signaling using rapamycin (20 nM), FK506 (5 nM), or 4EGI-1 (1 µM), and siRNA knockdown of mTOR, or the mTOR complex binding proteins, raptor or rictor, blocked PCB 95-induced dendritic growth. These data identify mTOR activation as a novel molecular mechanism contributing to the effects of PCB 95 on dendritic arborization. In light of clinical data linking gain-of-function mutations in mTOR signaling to neurodevelopmental disorders, our findings suggest that mTOR signaling may represent a convergence point for gene by environment interactions that confer risk for adverse neurodevelopmental outcomes.
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30
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Chen YW, Akad A, Aderogba R, Chowdhury TG, Aoki C. Dendrites of the dorsal and ventral hippocampal CA1 pyramidal neurons of singly housed female rats exhibit lamina-specific growths and retractions during adolescence that are responsive to pair housing. Synapse 2018; 72:e22034. [PMID: 29631321 DOI: 10.1002/syn.22034] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [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: 02/26/2018] [Revised: 03/27/2018] [Accepted: 04/01/2018] [Indexed: 01/07/2023]
Abstract
Adolescence is accompanied by increased vulnerability to psychiatric illnesses, including anxiety, depression, schizophrenia, and eating disorders. The hippocampus is important for regulating emotional state through its ventral compartment and spatial cognition through its dorsal compartment. Previous animal studies have examined hippocampal development at stages before, after or at single time points during adolescence. However, only one study has investigated morphological changes at multiple time points during adolescence, and no study has yet compared developmental changes of dorsal versus ventral hippocampi. We analyzed the dorsal and ventral hippocampi of rats to determine the developmental trajectory of Golgi-stained hippocampal CA1 neurons by sampling at five time points, ranging from postnatal day (P) 35 (puberty) to 55 (end of adolescence). We show that the dorsal hippocampus undergoes transient dendritic retractions in stratum radiatum (SR), while the ventral hippocampus undergoes transient dendritic growths in SR. During adulthood, stress and hormonal fluctuations have been shown to alter the physiology and morphology of hippocampal neurons, but studies of the impact of these factors upon adolescent hippocampi are scarce. In addition, we show that female-female pair housing from P 36-44 significantly increases branching in the dorsal SR and reduces branching in the ventral SR. Taken together with data on spine density, these results indicate that pyramidal cells in the dorsal and ventral CA1 of female adolescents are remodeled differently following single housing. Social housing during adolescence elicits pathway-specific changes in the hippocampus that may underlie behavioral benefits, including stability of emotion regulation and superior cognition.
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Affiliation(s)
- Yi-Wen Chen
- Center for Neural Science, New York University, New York, New York 10003
| | - Ada Akad
- Center for Neural Science, New York University, New York, New York 10003
| | - Ruka Aderogba
- Center for Neural Science, New York University, New York, New York 10003
| | - Tara G Chowdhury
- Center for Neural Science, New York University, New York, New York 10003
| | - Chiye Aoki
- Center for Neural Science, New York University, New York, New York 10003.,Neuroscience Institute, Langone Medical Center, New York University, New York, New York 10016
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31
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O'Neill KM, Donohue KE, Omelchenko A, Firestein BL. The 3' UTRs of Brain-Derived Neurotrophic Factor Transcripts Differentially Regulate the Dendritic Arbor. Front Cell Neurosci 2018; 12:60. [PMID: 29563866 PMCID: PMC5845904 DOI: 10.3389/fncel.2018.00060] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [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: 11/20/2017] [Accepted: 02/19/2018] [Indexed: 12/13/2022] Open
Abstract
The patterning of dendrites is regulated by many factors, such as brain-derived neurotrophic factor (BDNF), which our laboratory has previously shown alters the dendritic arbor uniquely depending on the mode of extracellular application. In the current work, we examine how BDNF affects dendritogenesis in hippocampal neurons when it is overexpressed intracellularly by transcripts previously reported to be transported to distinct cellular compartments. The BDNF gene is processed at two different polyadenylation sites, leading to mRNA transcription with two different length 3′ untranslated regions (UTRs), and therefore, different mRNA localization preferences. We found that overexpression of BDNF mRNA with or without 3′ UTRs significantly alters dendritic branching compared to branching in control neurons as analyzed by Sholl distribution curves. Unexpectedly, we found that the overexpression of the shorter BDNF mRNA (reported to be preferentially targeted to the cell body) results in similar changes to Sholl curves compared to overexpression of the longer BDNF mRNA (reported to be preferentially targeted to both the cell body and dendrites). We also investigated whether the BDNF receptor TrkB mediates these changes and found that inhibiting TrkB blocks increases in Sholl curves, although at different distances depending on the transcript’s UTR. Finally, although it is not found in nature, we also examined the effects of overexpressing BDNF mRNA with the unique portion of the longer 3′ UTR since it was previously shown to be necessary for dendritic targeting of mRNA. We found that its overexpression increases Sholl curves at distances close to the cell body and that these changes also depend on TrkB activity. This work illustrates how the mRNA spatial code affects how BDNF alters local dendritogenesis and how TrkB may mediate these effects. Finally, our findings emphasize the importance of intracellular transport of BDNF mRNAs in the regulation of dendrite morphology.
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Affiliation(s)
- Kate M O'Neill
- Department of Cell Biology and Neuroscience, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States.,Graduate Program in Biomedical Engineering, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
| | - Katherine E Donohue
- Department of Cell Biology and Neuroscience, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
| | - Anton Omelchenko
- Department of Cell Biology and Neuroscience, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States.,Graduate Program in Neuroscience, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
| | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States.,Biomedical Engineering Graduate Faculty, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States.,Neuroscience Graduate Faculty, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
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Abstract
Most neurons elaborate a characteristic dendritic arbor which is physiologically important for receiving and processing of synaptic inputs. Pathologically, disturbances in the regulation of dendritic tree complexity are often associated with mental retardation and other neurological deficits. Rho GTPases are major players in the regulation of dendritic tree complexity. They are involved in many signal transduction cascades, activated at the neuronal plasma membrane, and relayed to intracellular proteins that directly rearrange the cytoskeleton. The use of siRNA technology combined with morphometric and imaging techniques allows the roles of individual Rho GTPases, such as Rac1, in dendritic branching to be examined. In this chapter we describe the establishment, transfection, and processing of a primary hippocampal cell culture. Methods to assess the complexity of dendritic arbors like the Sholl analysis, and techniques to investigate Rac1 activity in hippocampal cells, and specifically in neuronal dendrites, such as fluorescence resonance energy transfer (FRET) imaging are presented.
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Affiliation(s)
- Jana Schulz
- Institute of Molecular and Cellular Anatomy, Ulm University, Ulm, Germany
| | - Stefan Schumacher
- Institute of Molecular and Cellular Anatomy, Ulm University, Ulm, Germany.
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33
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Brick RM, Sun AX, Tuan RS. Neurotrophically Induced Mesenchymal Progenitor Cells Derived from Induced Pluripotent Stem Cells Enhance Neuritogenesis via Neurotrophin and Cytokine Production. Stem Cells Transl Med 2017; 7:45-58. [PMID: 29215199 PMCID: PMC5746147 DOI: 10.1002/sctm.17-0108] [Citation(s) in RCA: 18] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 11/06/2017] [Indexed: 12/11/2022] Open
Abstract
Adult tissue‐derived mesenchymal stem cells (MSCs) are known to produce a number of bioactive factors, including neurotrophic growth factors, capable of supporting and improving nerve regeneration. However, with a finite culture expansion capacity, MSCs are inherently limited in their lifespan and use. We examined here the potential utility of an alternative, mesenchymal‐like cell source, derived from induced pluripotent stem cells, termed induced mesenchymal progenitor cells (MiMPCs). We found that several genes were upregulated and proteins were produced in MiMPCs that matched those previously reported for MSCs. Like MSCs, the MiMPCs secreted various neurotrophic and neuroprotective factors, including brain‐derived neurotrophic factor (BDNF), interleukin‐6 (IL‐6), leukemia inhibitory factor (LIF), osteopontin, and osteonectin, and promoted neurite outgrowth in chick embryonic dorsal root ganglia (DRG) cultures compared with control cultures. Cotreatment with a pharmacological Trk‐receptor inhibitor did not result in significant decrease in MiMPC‐induced neurite outgrowth, which was however inhibited upon Jak/STAT3 blockade. These findings suggest that the MiMPC induction of DRG neurite outgrowth is unlikely to be solely dependent on BDNF, but instead Jak/STAT3 activation by IL‐6 and/or LIF is likely to be critical neurotrophic signaling pathways of the MiMPC secretome. Taken together, these findings suggest MiMPCs as a renewable, candidate source of therapeutic cells and a potential alternative to MSCs for peripheral nerve repair, in view of their ability to promote nerve growth by producing many of the same growth factors and cytokines as Schwann cells and signaling through critical neurotrophic pathways. stemcellstranslational Medicine2018;7:45–58
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Affiliation(s)
- Rachel M Brick
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Aaron X Sun
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, Pennsylvania, USA
| | - Rocky S Tuan
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, Pennsylvania, USA
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34
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O'Neill KM, Kwon M, Donohue KE, Firestein BL. Distinct effects on the dendritic arbor occur by microbead versus bath administration of brain-derived neurotrophic factor. Cell Mol Life Sci 2017; 74:4369-85. [PMID: 28698933 DOI: 10.1007/s00018-017-2589-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 06/15/2017] [Accepted: 07/06/2017] [Indexed: 12/18/2022]
Abstract
Proper communication among neurons depends on an appropriately formed dendritic arbor, and thus, aberrant changes to the arbor are implicated in many pathologies, ranging from cognitive disorders to neurodegenerative diseases. Due to the importance of dendritic shape to neuronal network function, the morphology of dendrites is tightly controlled and is influenced by both intrinsic and extrinsic factors. In this work, we examine how brain-derived neurotrophic factor (BDNF), one of the most well-studied extrinsic regulators of dendritic branching, affects the arbor when it is applied locally via microbeads to cultures of hippocampal neurons. We found that local application of BDNF increases both proximal and distal branching in a time-dependent manner and that local BDNF application attenuates pruning of dendrites that occurs with neuronal maturation. Additionally, we examined whether cytosolic PSD-95 interactor (cypin), an intrinsic regulator of dendritic branching, plays a role in these changes and found strong evidence for the involvement of cypin in BDNF-promoted increases in dendrites after 24 but not 48 h of application. This current study extends our previous work in which we found that bath application of BDNF for 72 h, but not shorter times, increases proximal dendrite branching and that this increase occurs through transcriptional regulation of cypin. Moreover, this current work illustrates how dendritic branching is regulated differently by the same growth factor depending on its spatial localization, suggesting a novel pathway for modulation of dendritic branching locally.
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Gzielo K, Kielbinski M, Ploszaj J, Janeczko K, Gazdzinski SP, Setkowicz Z. Long-Term Consumption of High-Fat Diet in Rats: Effects on Microglial and Astrocytic Morphology and Neuronal Nitric Oxide Synthase Expression. Cell Mol Neurobiol 2017; 37:783-789. [PMID: 27541371 PMCID: PMC5435787 DOI: 10.1007/s10571-016-0417-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 08/10/2016] [Indexed: 12/30/2022]
Abstract
Obesity in humans is associated with cognitive decline and elevated risk of neurodegenerative diseases of old age. Variations of high-fat diet are often used to model these effects in animal studies. However, we previously reported improvements in markers of memory and learning, as well as larger hippocampi and higher metabolite concentrations in Wistar rats fed high-fat, high-carbohydrate diet (HFCD, 60 % energy from fat, 28 % from carbohydrates) for 1 year; this diet leads to mild ketonemia (Setkowicz et al. in PLoS One 10:e0139987, 2015). In the present study, we follow up on this cohort to assess glial morphology and expression of markers related to gliosis. Twenty-five male Wistar rats were kept on HFCD and twenty-five on normal chow. At 12 months of age, the animals were sacrificed and processed for immunohistochemical staining for astrocytic (glial fibrillary acidic protein), microglial (Iba1), and neuronal (neuronal nitric oxide synthetase, nNOS) markers in the hippocampus. We have found changes in immunopositive area fraction and cellular complexity, as studied by a simplified Sholl procedure. To our knowledge, this study is the first to apply this methodology to the study of glial cells in HFCD animals. GFAP and Iba1 immunoreactive area fraction in the hippocampi of HFCD-fed rats were decreased, while the mean number of intersections (an indirect measure of cell complexity) was decreased in GFAP-positive astrocytes, but not in Iba1-expressing microglia. At the same time, nNOS expression was lowered after HFCD in both the cortex and the hippocampus.
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Affiliation(s)
- Kinga Gzielo
- Department of Neuroanatomy, Jagiellonian University, Gronostajowa 9, 30-387, Kraków, Poland.
| | - Michal Kielbinski
- Department of Neuroanatomy, Jagiellonian University, Gronostajowa 9, 30-387, Kraków, Poland
| | - Jakub Ploszaj
- Department of Neuroanatomy, Jagiellonian University, Gronostajowa 9, 30-387, Kraków, Poland
| | - Krzysztof Janeczko
- Department of Neuroanatomy, Jagiellonian University, Gronostajowa 9, 30-387, Kraków, Poland
| | - Stefan P Gazdzinski
- Military Institute of Aviation Medicine, Krasinskiego 54, 01-755, Warsaw, Poland
| | - Zuzanna Setkowicz
- Department of Neuroanatomy, Jagiellonian University, Gronostajowa 9, 30-387, Kraków, Poland
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Wilson MD, Sethi S, Lein PJ, Keil KP. Valid statistical approaches for analyzing sholl data: Mixed effects versus simple linear models. J Neurosci Methods 2017; 279:33-43. [PMID: 28104486 PMCID: PMC5346342 DOI: 10.1016/j.jneumeth.2017.01.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 01/27/2023]
Abstract
BACKGROUND The Sholl technique is widely used to quantify dendritic morphology. Data from such studies, which typically sample multiple neurons per animal, are often analyzed using simple linear models. However, simple linear models fail to account for intra-class correlation that occurs with clustered data, which can lead to faulty inferences. NEW METHOD Mixed effects models account for intra-class correlation that occurs with clustered data; thus, these models more accurately estimate the standard deviation of the parameter estimate, which produces more accurate p-values. While mixed models are not new, their use in neuroscience has lagged behind their use in other disciplines. RESULTS A review of the published literature illustrates common mistakes in analyses of Sholl data. Analysis of Sholl data collected from Golgi-stained pyramidal neurons in the hippocampus of male and female mice using both simple linear and mixed effects models demonstrates that the p-values and standard deviations obtained using the simple linear models are biased downwards and lead to erroneous rejection of the null hypothesis in some analyses. COMPARISON WITH EXISTING METHODS The mixed effects approach more accurately models the true variability in the data set, which leads to correct inference. CONCLUSIONS Mixed effects models avoid faulty inference in Sholl analysis of data sampled from multiple neurons per animal by accounting for intra-class correlation. Given the widespread practice in neuroscience of obtaining multiple measurements per subject, there is a critical need to apply mixed effects models more widely.
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Affiliation(s)
- Machelle D Wilson
- Clinical and Translational Science Center, Department of Public Health Sciences, Division of Biostatistics, University of California, Davis, CA, United States
| | - Sunjay Sethi
- Department of Molecular Biosciences, University of California, Davis, CA, United States
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, CA, United States
| | - Kimberly P Keil
- Department of Molecular Biosciences, University of California, Davis, CA, United States.
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Aoki C, Chowdhury TG, Wable GS, Chen YW. Synaptic changes in the hippocampus of adolescent female rodents associated with resilience to anxiety and suppression of food restriction-evoked hyperactivity in an animal model for anorexia nervosa. Brain Res 2017; 1654:102-115. [PMID: 26779892 PMCID: PMC4947030 DOI: 10.1016/j.brainres.2016.01.019] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 01/10/2016] [Indexed: 12/30/2022]
Abstract
Anorexia nervosa is a mental illness that emerges primarily during early adolescence, with mortality rate that is 200 times higher than that of suicide. The illness is characterized by intense fear of gaining weight, heightened anxiety, obstinate food restriction, often accompanied by excessive exercise, in spite of mounting hunger. The illness affects females nine times more often than males, suggesting an endocrine role in its etiology. Its relapse rate exceeds 25%, yet there are no accepted pharmacological treatments to prevent this. Here, we summarize studies from this laboratory that have used adolescent female rodents in activity-based anorexia (ABA), an animal model of anorexia nervosa, with the goal of identifying neurobiological underpinnings of this disease. We put forth a hypothesis that a GABAergic mechanism within the hippocampus is central to regulating an individual׳s anxiety which, in turn, strongly influences the individual׳s resilience/vulnerability to ABA. In particular, we propose that ionotropic GABAA receptors containing the subunits alpha4 and delta, are at play for exerting shunting inhibition upon hippocampal pyramidal neurons that become more excitable during ABA. Since these receptors confer insensitivity to benzodiazepines, this pharmacological profile of ABA fits with lack of report indicating efficacy of benzodiazepines in reducing the anxiety experienced by individuals with anorexia nervosa. The idea that the GABAergic system of the hippocampus regulates resilience/vulnerability to anorexia nervosa complements current opinions about the important roles of the prefrontal cortex, amygdala, striatum, gustatory pathways and feeding centers of the hypothalamus and of the neuromodulators, serotonin and dopamine, in the etiology of the disease. This article is part of a Special Issue entitled SI: Adolescent plasticity.
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Affiliation(s)
- Chiye Aoki
- Center for Neural Science, 4 Washington Place, Room 809, New York, NY 10003, United States.
| | - Tara G Chowdhury
- Center for Neural Science, 4 Washington Place, Room 809, New York, NY 10003, United States
| | - Gauri S Wable
- Center for Neural Science, 4 Washington Place, Room 809, New York, NY 10003, United States
| | - Yi-Wen Chen
- Center for Neural Science, 4 Washington Place, Room 809, New York, NY 10003, United States
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Binley KE, Ng WS, Barde YA, Song B, Morgan JE. Brain-derived neurotrophic factor prevents dendritic retraction of adult mouse retinal ganglion cells. Eur J Neurosci 2016; 44:2028-39. [PMID: 27285957 PMCID: PMC4988502 DOI: 10.1111/ejn.13295] [Citation(s) in RCA: 21] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 06/02/2016] [Accepted: 06/06/2016] [Indexed: 01/24/2023]
Abstract
We used cultured adult mouse retinae as a model system to follow and quantify the retraction of dendrites using diolistic labelling of retinal ganglion cells (RGCs) following explantation. Cell death was monitored in parallel by nuclear staining as ‘labelling’ with RGC and apoptotic markers was inconsistent and exceedingly difficult to quantify reliably. Nuclear staining allowed us to delineate a lengthy time window during which dendrite retraction can be monitored in the absence of RGC death. The addition of brain‐derived neurotrophic factor (BDNF) produced a marked reduction in dendritic degeneration, even when application was delayed for 3 days after retinal explantation. These results suggest that the delayed addition of trophic factors may be functionally beneficial before the loss of cell bodies in the course of conditions such as glaucoma.
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Affiliation(s)
- Kate E Binley
- School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK
| | - Wai S Ng
- School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK
| | - Yves-Alain Barde
- School of Biosciences, Sir Martin Evans Building, Cardiff University, Cardiff, UK
| | - Bing Song
- School of Dentistry, Cardiff University, Heath Park, Cardiff, UK
| | - James E Morgan
- School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK
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Hensel N, Schön A, Konen T, Lübben V, Förthmann B, Baron O, Grothe C, Leifheit-Nestler M, Claus P, Haffner D. Fibroblast growth factor 23 signaling in hippocampal cells: impact on neuronal morphology and synaptic density. J Neurochem 2016; 137:756-69. [PMID: 26896818 DOI: 10.1111/jnc.13585] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [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: 11/19/2015] [Revised: 01/18/2016] [Accepted: 02/09/2016] [Indexed: 12/16/2022]
Abstract
Endocrine fibroblast growth factor 23 (FGF23) is predominantly secreted by osteocytes and facilitates renal phosphate excretion. However, FGF23 is also present in cerebrospinal fluid. In chronic kidney disease, FGF23 serum levels are excessively elevated and associated with learning and memory deficits. Structural plasticity of the hippocampus such as formation of new synapses or an altered dendritic arborization comprises a cellular and morphological correlate of memory formation. Therefore, we hypothesize that FGF23 alters hippocampal neuron morphology and synapses. To address this, we prepared primary murine hippocampal cultures and incubated them with recombinant FGF23 alone or together with a soluble isoform of its co-receptor α-Klotho. Neuronal expression of a fluorescent reporter allowed for a detailed evaluation of the neuronal morphology by Sholl analysis. Additionally, we evaluated synaptic density, identified by stainings, for synaptic markers. We show an enhanced number of primary neurites combined with a reduced arborization, resulting in a less complex morphology of neurons treated with FGF23. Moreover, FGF23 enhances the synaptic density in a FGF-receptor (FGF-R) dependent manner. Finally, we addressed the corresponding signaling events downstream of FGF-R employing a combination of western blots and quantitative immunofluorescence. Interestingly, FGF23 induces phospholipase Cγ activity in primary hippocampal neurons. Co-application of soluble α-Klotho leads to activation of the Akt-pathway and modifies FGF23-impact on neuronal morphology and synaptic density. Compared with other FGFs, this alternative signaling pattern is a possible reason for differential effects of FGF23 on hippocampal neurons and may thereby contribute to learning and memory deficits in chronic kidney disease patients. In this study, we show that fibroblast growth factor 23 inhibits neuronal ramification and enhances the synaptic density in primary hippocampal cultures accompanied by phospholipase Cγ-activation. Co-application of the co-receptor α-Klotho leads to an Akt-activation and further modifies neuronal morphology and number of synapses. Those effects provide a mechanistic basis for memory deficits in patients suffering from chronic kidney disease (CKD) characterized by excessively elevated FGF23 levels as well as memory deficits.
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Affiliation(s)
- Niko Hensel
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
| | - Anne Schön
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Timo Konen
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
| | - Verena Lübben
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany.,Center of Systems Neuroscience (ZSN) Hannover, Hannover, Germany
| | | | - Olga Baron
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
| | - Claudia Grothe
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany.,Center of Systems Neuroscience (ZSN) Hannover, Hannover, Germany
| | - Maren Leifheit-Nestler
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Peter Claus
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany.,Center of Systems Neuroscience (ZSN) Hannover, Hannover, Germany
| | - Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
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Gao F, Song X, Zhu D, Wang X, Hao A, Nadler JV, Zhan RZ. Dendritic morphology, synaptic transmission, and activity of mature granule cells born following pilocarpine-induced status epilepticus in the rat. Front Cell Neurosci 2015; 9:384. [PMID: 26500490 PMCID: PMC4596052 DOI: 10.3389/fncel.2015.00384] [Citation(s) in RCA: 12] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 09/14/2015] [Indexed: 01/23/2023] Open
Abstract
To understand the potential role of enhanced hippocampal neurogenesis after pilocarpine-induced status epilepticus (SE) in the development of epilepsy, we quantitatively analyzed the geometry of apical dendrites, synaptic transmission, and activation levels of normotopically distributed mature newborn granule cells in the rat. SE in male Sprague-Dawley rats (between 6 and 7 weeks old) lasting for more than 2 h was induced by an intraperitoneal injection of pilocarpine. The complexity, spine density, miniature post-synaptic currents, and activity-regulated cytoskeleton-associated protein (Arc) expression of granule cells born 5 days after SE were studied between 10 and 17 weeks after CAG-GFP retroviral vector-mediated labeling. Mature granule cells born after SE had dendritic complexity similar to that of granule cells born naturally, but with denser mushroom-like spines in dendritic segments located in the outer molecular layer. Miniature inhibitory post-synaptic currents (mIPSCs) were similar between the controls and rats subjected to SE; however, smaller miniature excitatory post-synaptic current (mEPSC) amplitude with a trend toward less frequent was found in mature granule cells born after SE. After maturation, granule cells born after SE did not show denser Arc expression in the resting condition or 2 h after being activated by pentylenetetrazol-induced transient seizure activity than vicinal GFP-unlabeled granule cells. Thus our results suggest that normotopic granule cells born after pilocarpine-induced SE are no more active when mature than age-matched, naturally born granule cells.
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Affiliation(s)
- Fei Gao
- Department of Physiology, Shandong University School of Medicine Jinan, China
| | - Xueying Song
- Department of Physiology, Shandong University School of Medicine Jinan, China
| | - Dexiao Zhu
- Department of Physiology, Shandong University School of Medicine Jinan, China
| | - Xiaochen Wang
- Department of Physiology, Shandong University School of Medicine Jinan, China
| | - Aijun Hao
- Department of Histology and Embryology, Shandong University School of Medicine Jinan, China
| | - J Victor Nadler
- Departments of Pharmacology and Neurobiology, Duke University Medical Center Durham, NC, USA
| | - Ren-Zhi Zhan
- Department of Physiology, Shandong University School of Medicine Jinan, China
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Rietveld L, Stuss DP, McPhee D, Delaney KR. Genotype-specific effects of Mecp2 loss-of-function on morphology of Layer V pyramidal neurons in heterozygous female Rett syndrome model mice. Front Cell Neurosci 2015; 9:145. [PMID: 25941473 PMCID: PMC4403522 DOI: 10.3389/fncel.2015.00145] [Citation(s) in RCA: 25] [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: 02/18/2015] [Accepted: 03/29/2015] [Indexed: 01/29/2023] Open
Abstract
Rett syndrome (RTT) is a progressive neurological disorder primarily caused by mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2). The heterozygous female brain consists of mosaic of neurons containing both wild-type MeCP2 (MeCP2+) and mutant MeCP2 (MeCP2-). Three-dimensional morphological analysis was performed on individually genotyped layer V pyramidal neurons in the primary motor cortex of heterozygous (Mecp2(+/-) ) and wild-type (Mecp2(+/+) ) female mice ( > 6 mo.) from the Mecp2(tm1.1Jae) line. Comparing basal dendrite morphology, soma and nuclear size of MeCP2+ to MeCP2- neurons reveals a significant cell autonomous, genotype specific effect of Mecp2. MeCP2- neurons have 15% less total basal dendritic length, predominantly in the region 70-130 μm from the cell body and on average three fewer branch points, specifically loss in the second and third branch orders. Soma and nuclear areas of neurons of mice were analyzed across a range of ages (5-21 mo.) and X-chromosome inactivation (XCI) ratios (12-56%). On average, MeCP2- somata and nuclei were 15 and 13% smaller than MeCP2+ neurons respectively. In most respects branching morphology of neurons in wild-type brains (MeCP2 WT) was not distinguishable from MeCP2+ but somata and nuclei of MeCP2 WT neurons were larger than those of MeCP2+ neurons. These data reveal cell autonomous effects of Mecp2 mutation on dendritic morphology, but also suggest non-cell autonomous effects with respect to cell size. MeCP2+ and MeCP2- neuron sizes were not correlated with age, but were correlated with XCI ratio. Unexpectedly the MeCP2- neurons were smallest in brains where the XCI ratio was highly skewed toward MeCP2+, i.e., wild-type. This raises the possibility of cell non-autonomous effects that act through mechanisms other than globally secreted factors; perhaps competition for synaptic connections influences cell size and morphology in the genotypically mosaic brain of RTT model mice.
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Affiliation(s)
- Leslie Rietveld
- Department of Biology, University of Victoria Victoria, BC, Canada
| | - David P Stuss
- Department of Biology, University of Victoria Victoria, BC, Canada
| | - David McPhee
- Department of Biology, University of Victoria Victoria, BC, Canada
| | - Kerry R Delaney
- Department of Biology, University of Victoria Victoria, BC, Canada
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42
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Stanko JP, Easterling MR, Fenton SE. Application of Sholl analysis to quantify changes in growth and development in rat mammary gland whole mounts. Reprod Toxicol 2014; 54:129-35. [PMID: 25463529 DOI: 10.1016/j.reprotox.2014.11.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [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: 07/08/2014] [Revised: 10/07/2014] [Accepted: 11/07/2014] [Indexed: 10/24/2022]
Abstract
Studies that utilize the rodent mammary gland (MG) as an endpoint for assessing the developmental toxicity of chemical exposures typically employ either basic dimensional measurements or developmental scoring of morphological characteristics as a means to quantify MG development. There are numerous means by which to report these developmental changes, leading to inconsistent translation across laboratories. The Sholl analysis is a method historically used for quantifying neuronal dendritic patterns. The present study describes the use of the Sholl analysis to quantify MG branching characteristics. Using this method, we were able to detect significant differences in branching density in MG of peripubertal female Sprague Dawley rats that had been exposed to vehicle or a potent estrogen. These data suggest the Sholl analysis can be an effective tool for quantitatively measuring an important characteristic of MG development and for examining associations between MG growth and density and adverse effects in the breast.
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Affiliation(s)
- Jason P Stanko
- National Toxicology Program Laboratory, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, United States
| | | | - Suzanne E Fenton
- National Toxicology Program Laboratory, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, United States.
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43
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Ryan SJ, Ehrlich DE, Rainnie DG. Morphology and dendritic maturation of developing principal neurons in the rat basolateral amygdala. Brain Struct Funct 2014; 221:839-54. [PMID: 25381464 DOI: 10.1007/s00429-014-0939-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [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: 03/21/2014] [Accepted: 11/01/2014] [Indexed: 02/08/2023]
Abstract
The basolateral nucleus of the amygdala (BLA) assigns emotional valence to sensory stimuli, and many amygdala-dependent behaviors undergo marked development during postnatal life. We recently showed principal neurons in the rat BLA undergo dramatic changes to their electrophysiological properties during the first postnatal month, but no study to date has thoroughly characterized changes to morphology or gene expression that may underlie the functional development of this neuronal population. We addressed this knowledge gap with reconstructions of biocytin-filled principal neurons in the rat BLA at postnatal days 7 (P7), 14, 21, 28, and 60. BLA principal neurons underwent a number of morphological changes, including a twofold increase in soma volume from P7 to P21. Dendritic arbors expanded significantly during the first postnatal month and achieved a mature distribution around P28, in terms of total dendritic length and distance from soma. The number of primary dendrites and branch points were consistent with age, but branch points were found farther from the soma in older animals. Dendrites of BLA principal neurons at P7 had few spines, and spine density increased nearly fivefold by P21. Given the concurrent increase in dendritic material, P60 neurons had approximately 17 times as many total spines as P7 neurons. Together, these developmental transitions in BLA principal neuron morphology help explain a number of concomitant electrophysiological changes during a critical period in amygdala development.
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Affiliation(s)
- Steven J Ryan
- Department of Psychiatry and Behavioral Sciences, Division of Behavioral Neuroscience and Psychiatric Disorders, Yerkes Research Center, Emory University School of Medicine, 954 Gatewood Rd., Atlanta, GA, 30033, USA
| | - David E Ehrlich
- Department of Psychiatry and Behavioral Sciences, Division of Behavioral Neuroscience and Psychiatric Disorders, Yerkes Research Center, Emory University School of Medicine, 954 Gatewood Rd., Atlanta, GA, 30033, USA
| | - Donald G Rainnie
- Department of Psychiatry and Behavioral Sciences, Division of Behavioral Neuroscience and Psychiatric Disorders, Yerkes Research Center, Emory University School of Medicine, 954 Gatewood Rd., Atlanta, GA, 30033, USA.
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44
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Garcia-Segura LM, Perez-Marquez J. A new mathematical function to evaluate neuronal morphology using the Sholl analysis. J Neurosci Methods 2014; 226:103-109. [PMID: 24503022 DOI: 10.1016/j.jneumeth.2014.01.016] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [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: 10/02/2013] [Revised: 01/15/2014] [Accepted: 01/16/2014] [Indexed: 11/15/2022]
Abstract
BACKGROUND The Sholl analysis is a morphometric method that evaluates the neurite architecture of neurons by drawing a series of concentric circles around the cell soma. Based on the Sholl analysis, one mathematical method that gives a measure of the neurite arborization is the Schoenen ramification index (SRI): the ratio between the maximum number of the intersections of the neurites with the circles and the number of the primary neurites. A different method is the quantification of the number of bifurcations of the neurites (BN). NEW METHOD In this study we proposed a new mathematical function to quantify neurite morphology that we named the branching index (BI). The BI compares the difference in the number of intersections made in pairs of circles relative to the distance from the neuronal soma. To facilitate the morphometric analysis, we developed informatics software named CellTarget that obtains the quantitative variables of the Sholl analysis and neurite branching. RESULTS Using that bioinformatics application we compared the BI, the SRI and BN values in neuronal models and in neuronal hippocampal cultures treated or untreated with the androgen dihydrotestosterone, which is known to induce neurite branching. COMPARISON WITH EXISTING METHODS Although the SRI and the BN provided quantitative information of the degree of neurite morphology, it produced similar values in neurons that ramify very differently. By contrast, these differences were discriminated using the BI. CONCLUSIONS The BI is a useful parameter to discriminate among different neuronal morphologies.
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Affiliation(s)
| | - Julio Perez-Marquez
- Departamento de Biomedicina y Biotecnología, Universidad Alcalá de Henares, 28871 Madrid, Spain.
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45
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Arguello A, Cheyette BN. Dapper Antagonist of Catenin-1 (Dact1) contributes to dendrite arborization in forebrain cortical interneurons. Commun Integr Biol 2013; 6:e26656. [PMID: 24567777 PMCID: PMC3925456 DOI: 10.4161/cib.26656] [Citation(s) in RCA: 6] [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: 09/11/2013] [Accepted: 09/30/2013] [Indexed: 01/04/2023] Open
Abstract
In mice, genetically engineered knockout of the Dapper Antagonist of Catenin-1 (Dact1) locus, which encodes a scaffold protein involved in Wnt signaling, leads to decreased excitatory input formation on dendrites of developing forebrain neurons. We have previously demonstrated this in both (excitatory, glutamatergic) pyramidal neurons of the hippocampus and in (inhibitory GABAergic) interneurons of the cortex. We have also demonstrated that knockout of the Dact1 locus leads to decreased dendrite complexity in cultured hippocampal pyramidal neurons, and to decreased spine formation on dendrites of forebrain pyramidal neurons in vitro and in vivo. Synapse phenotypes resulting from Dact1 loss in cultured cortical interneurons can be rescued by recombinant overexpression of the Dact1 binding partner, Dishevelled-1 (Dvl1), but not by recombinant expression of a constitutively active form of the small GTPase Rac1. This contrasts with dendrite spine phenotypes resulting from Dact1 loss in cultured hippocampal pyramidal neurons, which can be fully rescued by recombinant expression of activated Rac1. Taken together, these data suggest that in maturing forebrain neurons there are molecularly separate requirements for Dact1 in dendrite arborization/spine formation vs. synaptogenesis. Here, we show that the developmental requirement for Dact1 during dendrite arborization, which we previously demonstrated only in hippocampal pyramidal neurons, is also present in cortical interneurons, and we discuss mechanistic implications of this finding.
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Affiliation(s)
- Annie Arguello
- Biomedical Sciences Graduate Program; University of California San Francisco; San Francisco, CA USA
| | - Benjamin Nr Cheyette
- Biomedical Sciences Graduate Program; University of California San Francisco; San Francisco, CA USA ; Department of Psychiatry; The Nina Ireland Laboratory of Developmental Neurobiology; University of California San Francisco; San Francisco, CA USA
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