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Espadas I, Wingfield J, Grinman E, Ghosh I, Chanda K, Nakahata Y, Bauer K, Raveendra B, Kiebler M, Yasuda R, Rangaraju V, Puthanveettil S. SLAMR, a synaptically targeted lncRNA, facilitates the consolidation of contextual fear memory. RESEARCH SQUARE 2023:rs.3.rs-2489387. [PMID: 36993323 PMCID: PMC10055528 DOI: 10.21203/rs.3.rs-2489387/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
LncRNAs are involved in critical processes for cell homeostasis and function. However, it remains largely unknown whether and how the transcriptional regulation of long noncoding RNAs results in activity-dependent changes at the synapse and facilitate formation of long-term memories. Here, we report the identification of a novel lncRNA, SLAMR, that becomes enriched in CA1- but not in CA3-hippocampal neurons upon contextual fear conditioning. SLAMR is transported to dendrites via the molecular motor KIF5C and recruited to the synapse in response to stimulation. Loss of function of SLAMR reduced dendritic complexity and impaired activity dependent changes in spine structural plasticity. Interestingly, gain of function of SLAMR enhanced dendritic complexity, and spine density through enhanced translation. Analyses of the SLAMR interactome revealed its association with CaMKIIα protein through a 220-nucleotide element and its modulation of CaMKIIα activity. Furthermore, loss-of-function of SLAMR in CA1 selectively impairs consolidation but neither acquisition, recall, nor extinction of fear memory and spatial memory. Together, these results establish a new mechanism for activity dependent changes at the synapse and consolidation of contextual fear.
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Affiliation(s)
- Isabel Espadas
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | - Jenna Wingfield
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | - Eddie Grinman
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | - Ilika Ghosh
- Max Planck Florida Institute, Jupiter, FL, USA
| | - Kaushik Chanda
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | | | - Karl Bauer
- Biomedical Center (BMC), Department for Cell Biology, Medical Faculty, Ludwig-Maximilians-University of Munich, 82152 Planegg-Martinsried, Germany
| | - Bindu Raveendra
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | - Michael Kiebler
- Biomedical Center (BMC), Department for Cell Biology, Medical Faculty, Ludwig-Maximilians-University of Munich, 82152 Planegg-Martinsried, Germany
| | | | | | - Sathyanarayanan Puthanveettil
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
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Hatakeyama D, Chikamoto N, Fujimoto K, Kitahashi T, Ito E. Comparison between relative and absolute quantitative real-time PCR applied to single-cell analyses: Transcriptional levels in a key neuron for long-term memory in the pond snail. PLoS One 2022; 17:e0279017. [PMID: 36508476 PMCID: PMC9744327 DOI: 10.1371/journal.pone.0279017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/28/2022] [Indexed: 12/14/2022] Open
Abstract
Quantitative real-time PCR (qPCR) is a powerful method for measuring nucleic acid levels and quantifying mRNA levels, even in single cells. In the present study, we compared the results of single-cell qPCR obtained by different quantification methods (relative and absolute) and different reverse transcription methods. In the experiments, we focused on the cerebral giant cell (CGC), a key neuron required for the acquisition of conditioned taste aversion in the pond snail Lymnaea stagnalis, and examined changes in the mRNA levels of 3 memory-related genes, cAMP-response element binding proteins (LymCREB1 and LymCREB2) and CREB-binding protein (LymCBP), during memory formation. The results obtained by relative quantification showed similar patterns for the 3 genes. For absolute quantification, reverse transcription was performed using 2 different methods: a mixture of oligo d(T) primers and random primers (RT method 1); and gene-specific primers (RT method 2). These methods yielded different results and did not show consistent changes related to conditioning. The mRNA levels in the samples prepared by RT method 2 were up to 3.3 times higher than those in samples prepared by RT method 1. These results suggest that for qPCR of single neurons, the efficacy and validity do not differ between relative and absolute quantification methods, but the reverse transcription step critically influences the results of mRNA quantification.
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Affiliation(s)
- Dai Hatakeyama
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima City, Japan
- * E-mail: (DH); (EI)
| | | | | | - Takashi Kitahashi
- Kushiro Nature Conservation Office, Ministry of the Environment Government of Japan, Kushiro City, Japan
| | - Etsuro Ito
- Department of Biology, Waseda University, Tokyo, Japan
- Graduate Institute of Medicine, School of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan
- * E-mail: (DH); (EI)
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Mendes-Silva AP, Prevot TD, Banasr M, Sibille E, Diniz BS. Abnormal expression of cortical cell cycle regulators underlying anxiety and depressive-like behavior in mice exposed to chronic stress. Front Cell Neurosci 2022; 16:999303. [PMID: 36568887 PMCID: PMC9772437 DOI: 10.3389/fncel.2022.999303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 11/22/2022] [Indexed: 12/12/2022] Open
Abstract
Background The cell cycle is a critical mechanism for proper cellular growth, development and viability. The p16INK4a and p21Waf1/Cip1 are important regulators of the cell cycle progression in response to internal and external stimuli (e.g., stress). Accumulating evidence indicates that the prefrontal cortex (PFC) is particularly vulnerable to stress, where stress induces, among others, molecular and morphological alterations, reflecting behavioral changes. Here, we investigated if the p16INK4a and p21Waf1/Cip1 expression are associated with behavioral outcomes. Methods Prefrontal cortex mRNA and protein levels of p16INK4A and p21Waf1/Cip1 of mice (six independent groups of C57BL/6J, eight mice/group, 50% female) exposed from 0 to 35 days of chronic restraint stress (CRS) were quantified by qPCR and Western Blot, respectively. Correlation analyses were used to investigate the associations between cyclin-dependent kinase inhibitors (CKIs) expression and anxiety- and depression-like behaviors. Results Our results showed that the PFC activated the cell cycle regulation pathways mediated by both CKIs p16INK4A and p21Waf1/Cip1 in mice exposed to CRS, with overall decreased mRNA expression and increased protein expression. Moreover, correlation analysis revealed that mRNA and protein levels are statistically significant correlated with anxiety and depressive-like behavior showing a greater effect in males than females. Conclusion Our present study extends the existing literature providing evidence that PFC cells respond to chronic stress exposure by overexpressing CKIs. Furthermore, our findings indicated that abnormal expression of p16INK4A and p21Waf1/Cip1 may significantly contribute to non-adaptive behavioral responses.
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Affiliation(s)
- Ana Paula Mendes-Silva
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada,*Correspondence: Ana Paula Mendes-Silva,
| | - Thomas Damien Prevot
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada,Department of Psychiatry, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Mounira Banasr
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada,Department of Psychiatry, Faculty of Medicine, University of Toronto, Toronto, ON, Canada,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Etienne Sibille
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada,Department of Psychiatry, Faculty of Medicine, University of Toronto, Toronto, ON, Canada,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Breno Satler Diniz
- School of Medicine, Center on Aging, University of Connecticut Health Center, Farmington, CT, United States,Department of Psychiatry, School of Medicine, University of Connecticut, Farmington, CT, United States
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4
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Clark KD, Rubakhin SS, Sweedler JV. Single-Neuron RNA Modification Analysis by Mass Spectrometry: Characterizing RNA Modification Patterns and Dynamics with Single-Cell Resolution. Anal Chem 2021; 93:14537-14544. [PMID: 34672536 PMCID: PMC8608286 DOI: 10.1021/acs.analchem.1c03507] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The entire collection of post-transcriptional modifications to RNA, known as the epitranscriptome, has been increasingly recognized as a critical regulatory layer in the cellular translation machinery. However, contemporary methods for the analysis of RNA modifications are limited to the detection of highly abundant modifications in bulk tissue samples, potentially obscuring unique epitranscriptomes of individual cells with population averages. We developed an approach, single-neuron RNA modification analysis by mass spectrometry (SNRMA-MS), that enables the detection and quantification of numerous post-transcriptionally modified nucleosides in single cells. When compared to a conventional RNA extraction approach that does not allow detection of RNA modifications in single cells, SNRMA-MS leverages an optimized sample preparation approach to detect up to 16 RNA modifications in individual neurons from the central nervous system of Aplysia californica. SNRMA-MS revealed that the RNA modification profiles of identified A. californica neurons with different physiological functions were mostly cell specific. However, functionally homologous neurons tended to demonstrate similar modification patterns. Stable isotope labeling with CD3-Met showed significant differences in RNA methylation rates that were dependent on the identity of the modification and the cell, with metacerebral cells (MCCs) displaying the fastest incorporation of CD3 groups into endogenous RNAs. Quantitative SNRMA-MS showed higher intracellular concentrations for 2'-O-methyladenosine and 2'-O-methylcytidine in homologous R2/LPl1 cell pairs than in MCCs. Overall, SNRMA-MS is the first analytical approach capable of simultaneously quantifying numerous RNA modifications in single neurons and revealing cell-specific modification profiles.
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Affiliation(s)
- Kevin D. Clark
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Stanislav S. Rubakhin
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Jonathan V. Sweedler
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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Kron NS, Fieber LA. Aplysia Neurons as a Model of Alzheimer's Disease: Shared Genes and Differential Expression. J Mol Neurosci 2021; 72:287-302. [PMID: 34664226 PMCID: PMC8840921 DOI: 10.1007/s12031-021-01918-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 09/18/2021] [Indexed: 11/19/2022]
Abstract
Although Alzheimer’s disease (AD) is the most common form of dementia in the United States, development of therapeutics has proven difficult. Invertebrate alternatives to current mammalian AD models have been successfully employed to study the etiology of the molecular hallmarks of AD. The marine snail Aplysia californica offers a unique and underutilized system in which to study the physiological, behavioral, and molecular impacts of AD. Mapping of the Aplysia proteome to humans and cross-referencing with two databases of genes of interest in AD research identified 898 potential orthologs of interest in Aplysia. Included among these orthologs were alpha, beta and gamma secretases, amyloid-beta, and tau. Comparison of age-associated differential expression in Aplysia sensory neurons with that of late-onset AD in the frontal lobe identified 59 ortholog with concordant differential expression across data sets. The 21 concordantly upregulated genes suggested increased cellular stress and protein dyshomeostasis. The 47 concordantly downregulated genes included important components of diverse neuronal processes, including energy metabolism, mitochondrial homeostasis, synaptic signaling, Ca++ regulation, and cellular cargo transport. Compromised functions in these processes are known hallmarks of both human aging and AD, the ramifications of which are suggested to underpin cognitive declines in aging and neurodegenerative disease.
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Affiliation(s)
- Nicholas S Kron
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Cswy, Miami, FL, 33149, USA.
| | - Lynne A Fieber
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Cswy, Miami, FL, 33149, USA
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6
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Kron NS, Fieber LA. Co-expression analysis identifies neuro-inflammation as a driver of sensory neuron aging in Aplysia californica. PLoS One 2021; 16:e0252647. [PMID: 34116561 PMCID: PMC8195618 DOI: 10.1371/journal.pone.0252647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 05/20/2021] [Indexed: 01/08/2023] Open
Abstract
Aging of the nervous system is typified by depressed metabolism, compromised proteostasis, and increased inflammation that results in cognitive impairment. Differential expression analysis is a popular technique for exploring the molecular underpinnings of neural aging, but technical drawbacks of the methodology often obscure larger expression patterns. Co-expression analysis offers a robust alternative that allows for identification of networks of genes and their putative central regulators. In an effort to expand upon previous work exploring neural aging in the marine model Aplysia californica, we used weighted gene correlation network analysis to identify co-expression networks in a targeted set of aging sensory neurons in these animals. We identified twelve modules, six of which were strongly positively or negatively associated with aging. Kyoto Encyclopedia of Genes analysis and investigation of central module transcripts identified signatures of metabolic impairment, increased reactive oxygen species, compromised proteostasis, disrupted signaling, and increased inflammation. Although modules with immune character were identified, there was no correlation between genes in Aplysia that increased in expression with aging and the orthologous genes in oyster displaying long-term increases in expression after a virus-like challenge. This suggests anti-viral response is not a driver of Aplysia sensory neuron aging.
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Affiliation(s)
- N. S. Kron
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States of America
| | - L. A. Fieber
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States of America
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7
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Kron NS, Schmale MC, Fieber LA. Changes in Metabolism and Proteostasis Drive Aging Phenotype in Aplysia californica Sensory Neurons. Front Aging Neurosci 2020; 12:573764. [PMID: 33101008 PMCID: PMC7522570 DOI: 10.3389/fnagi.2020.573764] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 08/12/2020] [Indexed: 12/29/2022] Open
Abstract
Aging is associated with cognitive declines that originate in impairments of function in the neurons that make up the nervous system. The marine mollusk Aplysia californica (Aplysia) is a premier model for the nervous system uniquely suited to investigation of neuronal aging due to uniquely identifiable neurons and molecular techniques available in this model. This study describes the molecular processes associated with aging in two populations of sensory neurons in Aplysia by applying RNA sequencing technology across the aging process (age 6-12 months). Differentially expressed genes clustered into four to five coherent expression patterns across the aging time series in the two neuron populations. Enrichment analysis of functional annotations in these neuron clusters revealed decreased expression of pathways involved in energy metabolism and neuronal signaling, suggesting that metabolic and signaling pathways are intertwined. Furthermore, increased expression of pathways involved in protein processing and translation suggests that proteostatic stress also occurs in aging. Temporal overlap of enrichment for energy metabolism, proteostasis, and neuronal function suggests that cognitive impairments observed in advanced age result from the ramifications of broad declines in energy metabolism.
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Affiliation(s)
- Nicholas S Kron
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States
| | - Michael C Schmale
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States
| | - Lynne A Fieber
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States
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8
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Badal KK, Akhmedov K, Lamoureux P, Liu XA, Reich A, Fallahi-Sichani M, Swarnkar S, Miller KE, Puthanveettil SV. Synapse Formation Activates a Transcriptional Program for Persistent Enhancement in the Bi-directional Transport of Mitochondria. Cell Rep 2020; 26:507-517.e3. [PMID: 30650345 DOI: 10.1016/j.celrep.2018.12.073] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 11/18/2018] [Accepted: 12/17/2018] [Indexed: 12/21/2022] Open
Abstract
Mechanisms that regulate the bi-directional transport of mitochondria in neurons for maintaining functional synaptic connections are poorly understood. Here, we show that in the pre-synaptic sensory neurons of the Aplysia gill withdrawal reflex, the formation of functional synapses leads to persistent enhancement in the flux of bi-directional mitochondrial transport. In the absence of a functional synapse, activation of cAMP signaling is sufficient to enhance bi-directional transport in sensory neurons. Furthermore, persistent enhancement in transport does not depend on NMDA and AMPA receptor signaling nor signaling from the post-synaptic neuronal cell body, but it is dependent on transcription and protein synthesis in the pre-synaptic neuron. We identified ∼4,000 differentially enriched transcripts in pre-synaptic neurons, suggesting a long-term change in the transcriptional program produced by synapse formation. These results provide insights into the regulation of bi-directional mitochondrial transport for synapse maintenance.
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Affiliation(s)
- Kerriann K Badal
- Department of Neuroscience, The Scripps Research Institute-Florida, 130 Scripps Way, Jupiter, FL 33458, USA; Integrative Biology PhD Program, Charles E. Schmidt College of Science, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Komol Akhmedov
- Department of Neuroscience, The Scripps Research Institute-Florida, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Phillip Lamoureux
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Xin-An Liu
- Department of Neuroscience, The Scripps Research Institute-Florida, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Adrian Reich
- Bioinformatics Core, The Scripps Research Institute-Florida, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Mohammad Fallahi-Sichani
- Bioinformatics Core, The Scripps Research Institute-Florida, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Supriya Swarnkar
- Department of Neuroscience, The Scripps Research Institute-Florida, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Kyle E Miller
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
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Tan YX, Hong Y, Jiang S, Lu MN, Li S, Chen B, Zhang L, Hu T, Mao R, Mei R, Xiyang YB. MicroRNA‑449a regulates the progression of brain aging by targeting SCN2B in SAMP8 mice. Int J Mol Med 2020; 45:1091-1102. [PMID: 32124967 PMCID: PMC7053848 DOI: 10.3892/ijmm.2020.4502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 01/29/2020] [Indexed: 12/23/2022] Open
Abstract
Our previous study demonstrated that the expression of sodium channel voltage-gated beta 2 (SCN2B) increased with aging in senescence-accelerated mouse prone 8 (SAMP8) mice, and was identified to be associated with a decline in learning and memory, while the underlying mechanism is unclear. In the present study, multiple differentially expressed miRNAs, which may be involved in the process of aging by regulating target genes, were identified in the prefrontal cortex and hippocampus of SAMP8 mice though miRNA microarray analysis. Using bioinformatics prediction, SCN2B was identified to be one of the potential target genes of miR-449a, which was downregulated in the hippocampus. Previous studies demonstrated that miR-449a is involved in the occurrence and progression of aging by regulating a variety of target genes. Therefore, it was hypothesized that miR-449a may be involved in the process of brain aging by targeting SCN2B. To verify this hypothesis, the following experiments were conducted: A reverse transcription-quantitative polymerase chain reaction assay revealed that the expression level of miR-449a was significantly decreased in the prefrontal cortex and hippocampus of 12-month old SAMP8 mice; a dual-luciferase reporter assay verified that miR-449a regulated SCN2B expression by binding to the 3′-UTR 'seed region'; an anti-Ago co-immunoprecipitation combined with Affymetrix micro-array analyses demonstrated that the target mRNA highly enriched with Ago-miRNPs was confirmed to be SCN2B. Finally, overexpression of miR-449a or inhibition of SCN2B promoted the extension of hippocampal neurons in vitro. The results of the present study suggested that miR-449a was downregulated in the prefrontal cortex and hippocampus of SAMP8 mice and may regulate the process of brain aging by targeting SCN2B.
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Affiliation(s)
- Ya-Xin Tan
- Institute of Neuroscience, Basic Medical College, Kunming Medical University, Kunming, Yunnan 650500, P.R. China
| | - Ying Hong
- Department of Laboratory Medicine, The Third People's Hospital of Yunnan Province, Kunming, Yunnan 650011, P.R. China
| | - Shui Jiang
- Department of Laboratory Medicine, The Third People's Hospital of Yunnan Province, Kunming, Yunnan 650011, P.R. China
| | - Min-Nan Lu
- Science and Technology Achievement Incubation Center, Kunming, Yunnan 650500, P.R. China
| | - Shan Li
- Institute of Neuroscience, Basic Medical College, Kunming Medical University, Kunming, Yunnan 650500, P.R. China
| | - Bo Chen
- Science and Technology Achievement Incubation Center, Kunming, Yunnan 650500, P.R. China
| | - Li Zhang
- Editorial Department of Journal of Kunming Medical University, Kunming, Yunnan 650500, P.R. China
| | - Tao Hu
- Department of Laboratory Medicine, The Third People's Hospital of Yunnan Province, Kunming, Yunnan 650011, P.R. China
| | - Rui Mao
- School of Stomatology, Kunming Medical University, Kunming, Yunnan 650500, P.R. China
| | - Rong Mei
- Department of Neurology, The First People's Hospital of Yunnan Province, Kunming, Yunnan 650032, P.R. China
| | - Yan-Bin Xiyang
- Institute of Neuroscience, Basic Medical College, Kunming Medical University, Kunming, Yunnan 650500, P.R. China
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Nguyen KV, Bihan DL, Ciobanu L, Li JR. The time-dependent diffusivity in the abdominal ganglion of
Aplysia californica:
experiments and simulations. Biomed Phys Eng Express 2019. [DOI: 10.1088/2057-1976/ab301e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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11
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Altered expression of ionotropic L-Glutamate receptors in aged sensory neurons of Aplysia californica. PLoS One 2019; 14:e0217300. [PMID: 31120976 PMCID: PMC6532900 DOI: 10.1371/journal.pone.0217300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 05/08/2019] [Indexed: 11/19/2022] Open
Abstract
The simplified nervous system of Aplysia californica (Aplysia) allows for detailed studies of physiological and molecular changes in small sets of neurons. Sensory neurons of the biting and tail withdrawal reflexes are glutamatergic and show reduced L-Glutamate current density in aged animals, making them a good candidate to study age-related changes in glutamatergic responses. To examine if changes in ionotropic L-Glu receptor (iGluR) transcription underlie reduced physiology, mRNA expression of iGluR was quantified in two sensory neuron clusters of two cohorts of Aplysia at both sexual maturity (~8 months) and advanced age (~12 months). Sensory neuron aging resulted in a significant overall decrease in expression of iGluR subunits in both sensory neuron clusters and cohorts. Although the individual subunits differentially expressed varied between sensory neuron clusters and different cohorts of animals, all differentially expressed subunits were downregulated, with no subunits showing significantly increased expression with age. Overall declines in transcript expression suggest that age-related declines in L-Glu responsiveness in Aplysia sensory neurons could be linked to overall declines in iGluR expression, rather than dysregulation of specific subunits. In both sensory neuron clusters tested the N-methyl-D-aspartate receptor subtype was expressed at significantly greater levels than other iGluR subtypes, suggesting an in vivo role for NMDAR-like receptors in Aplysia sensory neurons.
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12
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Burke SN, Foster TC. Animal models of cognitive aging and circuit-specific vulnerability. HANDBOOK OF CLINICAL NEUROLOGY 2019; 167:19-36. [PMID: 31753133 DOI: 10.1016/b978-0-12-804766-8.00002-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Medial temporal lobe and prefrontal cortical structures are particularly vulnerable to dysfunction in advanced age and neurodegenerative diseases. This review focuses on cognitive aging studies in animals to illustrate the important aspects of the animal model paradigm for investigation of age-related memory and executive function loss. Particular attention is paid to the discussion of the face, construct, and predictive validity of animal models for determining the possible mechanisms of regional vulnerability in aging and for identifying novel therapeutic strategies. Aging is associated with a host of regionally specific neurobiologic alterations. Thus, targeted interventions that restore normal activity in one brain region may exacerbate aberrant activity in another, hindering the restoration of function at the behavioral level. As such, interventions that target the optimization of "cognitive networks" rather than discrete brain regions may be more effective for improving functional outcomes in the elderly.
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Affiliation(s)
- Sara N Burke
- Department of Neuroscience, William L. and Evelyn F. McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Thomas C Foster
- Department of Neuroscience, William L. and Evelyn F. McKnight Brain Institute, University of Florida, Gainesville, FL, United States.
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13
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Hu Y, Pan J, Xin Y, Mi X, Wang J, Gao Q, Luo H. Gene Expression Analysis Reveals Novel Gene Signatures Between Young and Old Adults in Human Prefrontal Cortex. Front Aging Neurosci 2018; 10:259. [PMID: 30210331 PMCID: PMC6119720 DOI: 10.3389/fnagi.2018.00259] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 08/08/2018] [Indexed: 11/13/2022] Open
Abstract
Human neurons function over an entire lifetime, yet the molecular mechanisms which perform their functions and protecting against neurodegenerative disease during aging are still elusive. Here, we conducted a systematic study on the human brain aging by using the weighted gene correlation network analysis (WGCNA) method to identify meaningful modules or representative biomarkers for human brain aging. Significantly, 19 distinct gene modules were detected based on the dataset GSE53890; among them, six modules related to the feature of brain aging were highly preserved in diverse independent datasets. Interestingly, network feature analysis confirmed that the blue modules demonstrated a remarkably correlation with human brain aging progress. Besides, the top hub genes including PPP3CB, CAMSAP1, ACTR3B, and GNG3 were identified and characterized by high connectivity, module membership, or gene significance in the blue module. Furthermore, these genes were validated in mice of different ages. Mechanically, the potential regulators of blue module were investigated. These findings highlight an important role of the blue module and its affiliated genes in the control of normal brain aging, which may lead to potential therapeutic interventions for brain aging by targeting the hub genes.
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Affiliation(s)
- Yang Hu
- Department of Pharmacology, School of Medicine, Jinan University, Guangzhou, China.,Department of Pathology and Pathophysiology, School of Medicine, Jinan University, Guangzhou, China.,Institute of Brain Sciences, Jinan University, Guangzhou, China
| | - Junping Pan
- Department of Pharmacology, School of Medicine, Jinan University, Guangzhou, China
| | - Yirong Xin
- Department of Pharmacology, School of Medicine, Jinan University, Guangzhou, China
| | - Xiangnan Mi
- Department of Pharmacology, School of Medicine, Jinan University, Guangzhou, China
| | - Jiahui Wang
- Department of Pharmacology, School of Medicine, Jinan University, Guangzhou, China
| | - Qin Gao
- Department of Pharmacology, School of Medicine, Jinan University, Guangzhou, China
| | - Huanmin Luo
- Department of Pharmacology, School of Medicine, Jinan University, Guangzhou, China.,Institute of Brain Sciences, Jinan University, Guangzhou, China
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14
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Greer JB, Schmale MC, Fieber LA. Whole-transcriptome changes in gene expression accompany aging of sensory neurons in Aplysia californica. BMC Genomics 2018; 19:529. [PMID: 29996779 PMCID: PMC6042401 DOI: 10.1186/s12864-018-4909-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/29/2018] [Indexed: 02/07/2023] Open
Abstract
Background Large-scale molecular changes occur during aging and have many downstream consequences on whole-organism function, such as motor function, learning, and memory. The marine mollusk Aplysia californica can be used to study transcriptional changes that occur with age in identified neurons of the brain, because its simplified nervous system allows for more direct correlations between molecular changes, physiological changes, and their phenotypic outcomes. Behavioral deficits in the tail-withdrawal reflex of aged animals have been correlated with reduced excitation in sensory neurons that control the reflex. RNASeq was used to investigate whole-transcriptome changes in tail-withdrawal sensory neurons of sexually mature and aged Aplysia to correlate transcriptional changes with reduced behavioral and physiological responses. Results Paired-end sequencing resulted in 210 million reads used for differential expression analysis. Aging significantly altered expression of 1202 transcripts in sensory neurons underlying the tail-withdrawal reflex, with an approximately equal number of these genes up- and down regulated with age. Despite overall bidirectionality of expression changes, > 80% of ion channel genes that were differentially expressed had decreased expression with age. In particular, several voltage-gated K+ and Ca2+ channels were down regulated. This marked decrease in ion channel expression may play an important role in previously observed declines in aged sensory neuron excitability. We also observed decreased expression of genes and pathways involved in learning and memory. Genes involved in the stress response showed increased expression in aged Aplysia neurons. Conclusions Significantly altered expression of many genes between sexually mature and aged Aplysia suggests large molecular changes that may impact neuronal function. Decreased ion channel mRNA observed could mean fewer receptors present in aged neurons, resulting in reduced excitability of PVC sensory neurons, ultimately leading to reduced tail-withdrawal reflex observed in aged Aplysia. Significant changes in other genes and pathways, such as stress response and learning and memory, have previously been shown to occur with age in many vertebrate organisms. This suggests that some effects of aging are common across many animal phyla. Electronic supplementary material The online version of this article (10.1186/s12864-018-4909-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Justin B Greer
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Cswy, Miami, FL, 33149, USA.
| | - Michael C Schmale
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Cswy, Miami, FL, 33149, USA
| | - Lynne A Fieber
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Cswy, Miami, FL, 33149, USA
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15
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Ferreri F, Guerra A, Vollero L, Ponzo D, Maatta S, Mervaala E, Iannello G, Di Lazzaro V. Age-related changes of cortical excitability and connectivity in healthy humans: non-invasive evaluation of sensorimotor network by means of TMS-EEG. Neuroscience 2017. [DOI: 10.1016/j.neuroscience.2017.06.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Florinda Ferreri
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, University Campus Bio-Medico, via Álvaro del Portillo 21, 00128 Rome, Italy; Department of Clinical Neurophysiology, Kuopio University Hospital, University of Eastern Finland, 70029 KYS, Kuopio, Finland.
| | - Andrea Guerra
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, University Campus Bio-Medico, via Álvaro del Portillo 21, 00128 Rome, Italy
| | - Luca Vollero
- Department of Computer Science and Computer Engineering, University Campus Bio-Medico, via Álvaro del Portillo 200, 00128 Rome, Italy
| | - David Ponzo
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, University Campus Bio-Medico, via Álvaro del Portillo 21, 00128 Rome, Italy
| | - Sara Maatta
- Department of Clinical Neurophysiology, Kuopio University Hospital, University of Eastern Finland, 70029 KYS, Kuopio, Finland
| | - Esa Mervaala
- Department of Clinical Neurophysiology, Kuopio University Hospital, University of Eastern Finland, 70029 KYS, Kuopio, Finland
| | - Giulio Iannello
- Department of Computer Science and Computer Engineering, University Campus Bio-Medico, via Álvaro del Portillo 200, 00128 Rome, Italy
| | - Vincenzo Di Lazzaro
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, University Campus Bio-Medico, via Álvaro del Portillo 21, 00128 Rome, Italy
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16
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Dunn TW, Sossin WS. Decline in the Recovery from Synaptic Depression in Heavier Aplysia Results from Decreased Serotonin-Induced Novel PKC Activation. PLoS One 2015; 10:e0136907. [PMID: 26317974 PMCID: PMC4552628 DOI: 10.1371/journal.pone.0136907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/09/2015] [Indexed: 11/21/2022] Open
Abstract
The defensive withdrawal reflexes of Aplysia are important behaviors for protecting the animal from predation. Habituation and dishabituation allow for experience-dependent tuning of these reflexes and the mechanisms underlying these forms of behavioral plasticity involve changes in transmitter release from the sensory to motor neuron synapses through homosynaptic depression and the serotonin-mediated recovery from depression, respectively. Interestingly, dishabituation is reduced in older animals with no corresponding change in habituation. Here we show that the cultured sensory neurons of heavier animals (greater than 120g) that form synaptic connections with motor neurons have both reduced recovery from depression and reduced novel PKC Apl II activation with 5HT. The decrease in the recovery from depression correlated better with the size of the animal than the age of the animal. Much of this change in PKC activation and synaptic facilitation following depression can be rescued by direct activation of PKC Apl II with phorbol dibutyrate, suggesting a change in the signal transduction pathway upstream of PKC Apl II activation in the sensory neurons of larger animals.
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Affiliation(s)
- Tyler William Dunn
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Wayne S. Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
- * E-mail:
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17
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Kempsell AT, Fieber LA. Aging in Sensory and Motor Neurons Results in Learning Failure in Aplysia californica. PLoS One 2015; 10:e0127056. [PMID: 25970633 PMCID: PMC4430239 DOI: 10.1371/journal.pone.0127056] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 04/10/2015] [Indexed: 11/18/2022] Open
Abstract
The physiological and molecular mechanisms of age-related memory loss are complicated by the complexity of vertebrate nervous systems. This study takes advantage of a simple neural model to investigate nervous system aging, focusing on changes in learning and memory in the form of behavioral sensitization in vivo and synaptic facilitation in vitro. The effect of aging on the tail withdrawal reflex (TWR) was studied in Aplysia californica at maturity and late in the annual lifecycle. We found that short-term sensitization in TWR was absent in aged Aplysia. This implied that the neuronal machinery governing nonassociative learning was compromised during aging. Synaptic plasticity in the form of short-term facilitation between tail sensory and motor neurons decreased during aging whether the sensitizing stimulus was tail shock or the heterosynaptic modulator serotonin (5-HT). Together, these results suggest that the cellular mechanisms governing behavioral sensitization are compromised during aging, thereby nearly eliminating sensitization in aged Aplysia.
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Affiliation(s)
- Andrew T. Kempsell
- University of Miami, Rosenstiel School of Marine and Atmospheric Science, Department of Marine Biology and Ecology, Miami, Florida, United States of America
| | - Lynne A. Fieber
- University of Miami, Rosenstiel School of Marine and Atmospheric Science, Department of Marine Biology and Ecology, Miami, Florida, United States of America
- * E-mail:
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18
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Kadakkuzha BM, Liu XA, McCrate J, Shankar G, Rizzo V, Afinogenova A, Young B, Fallahi M, Carvalloza AC, Raveendra B, Puthanveettil SV. Transcriptome analyses of adult mouse brain reveal enrichment of lncRNAs in specific brain regions and neuronal populations. Front Cell Neurosci 2015; 9:63. [PMID: 25798087 PMCID: PMC4351618 DOI: 10.3389/fncel.2015.00063] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 02/10/2015] [Indexed: 11/13/2022] Open
Abstract
Despite the importance of the long non-coding RNAs (lncRNAs) in regulating biological functions, the expression profiles of lncRNAs in the sub-regions of the mammalian brain and neuronal populations remain largely uncharacterized. By analyzing RNASeq datasets, we demonstrate region specific enrichment of populations of lncRNAs and mRNAs in the mouse hippocampus and pre-frontal cortex (PFC), the two major regions of the brain involved in memory storage and neuropsychiatric disorders. We identified 2759 lncRNAs and 17,859 mRNAs in the hippocampus and 2561 lncRNAs and 17,464 mRNAs expressed in the PFC. The lncRNAs identified correspond to ~14% of the transcriptome of the hippocampus and PFC and ~70% of the lncRNAs annotated in the mouse genome (NCBIM37) and are localized along the chromosomes as varying numbers of clusters. Importantly, we also found that a few of the tested lncRNA-mRNA pairs that share a genomic locus display specific co-expression in a region-specific manner. Furthermore, we find that sub-regions of the brain and specific neuronal populations have characteristic lncRNA expression signatures. These results reveal an unexpected complexity of the lncRNA expression in the mouse brain.
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Affiliation(s)
- Beena M Kadakkuzha
- Department of Neuroscience, The Scripps Research Institute Jupiter, FL, USA
| | - Xin-An Liu
- Department of Neuroscience, The Scripps Research Institute Jupiter, FL, USA
| | - Jennifer McCrate
- Department of Neuroscience, The Scripps Research Institute Jupiter, FL, USA
| | - Gautam Shankar
- Informatics Core, The Scripps Research Institute Jupiter, FL, USA
| | - Valerio Rizzo
- Department of Neuroscience, The Scripps Research Institute Jupiter, FL, USA
| | - Alina Afinogenova
- Department of Neuroscience, The Scripps Research Institute Jupiter, FL, USA
| | - Brandon Young
- Genomics Core, The Scripps Research Institute Jupiter, FL, USA
| | - Mohammad Fallahi
- Informatics Core, The Scripps Research Institute Jupiter, FL, USA
| | | | - Bindu Raveendra
- Department of Neuroscience, The Scripps Research Institute Jupiter, FL, USA
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19
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Weiner-Gorzel K, Dempsey E, Milewska M, McGoldrick A, Toh V, Walsh A, Lindsay S, Gubbins L, Cannon A, Sharpe D, O'Sullivan J, Murphy M, Madden SF, Kell M, McCann A, Furlong F. Overexpression of the microRNA miR-433 promotes resistance to paclitaxel through the induction of cellular senescence in ovarian cancer cells. Cancer Med 2015; 4:745-58. [PMID: 25684390 PMCID: PMC4430267 DOI: 10.1002/cam4.409] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 12/07/2014] [Accepted: 12/12/2014] [Indexed: 12/18/2022] Open
Abstract
Annually, ovarian cancer (OC) affects 240,000 women worldwide and is the most lethal gynecological malignancy. High-grade serous OC (HGSOC) is the most common and aggressive OC subtype, characterized by widespread genome changes and chromosomal instability and is consequently poorly responsive to chemotherapy treatment. The objective of this study was to investigate the role of the microRNA miR-433 in the cellular response of OC cells to paclitaxel treatment. We show that stable miR-433 expression in A2780 OC cells results in the induction of cellular senescence demonstrated by morphological changes, downregulation of phosphorylated retinoblastoma (p-Rb), and an increase in β-galactosidase activity. Furthermore, in silico analysis identified four possible miR-433 target genes associated with cellular senescence: cyclin-dependent kinase 6 (CDK6), MAPK14, E2F3, and CDKN2A. Mechanistically, we demonstrate that downregulation of p-Rb is attributable to a miR-433-dependent downregulation of CDK6, establishing it as a novel miR-433 associated gene. Interestingly, we show that high miR-433 expressing cells release miR-433 into the growth media via exosomes which in turn can induce a senescence bystander effect. Furthermore, in relation to a chemotherapeutic response, quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that only PEO1 and PEO4 OC cells with the highest miR-433 expression survive paclitaxel treatment. Our data highlight how the aberrant expression of miR-433 can adversely affect intracellular signaling to mediate chemoresistance in OC cells by driving cellular senescence.
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Affiliation(s)
- Karolina Weiner-Gorzel
- UCD School of Medicine and Medical Science (SMMS), UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - Eugene Dempsey
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Ireland
| | | | - Aloysius McGoldrick
- UCD School of Medicine and Medical Science (SMMS), UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - Valerie Toh
- UCD School of Medicine and Medical Science (SMMS), UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - Aoibheann Walsh
- UCD School of Medicine and Medical Science (SMMS), UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - Sinead Lindsay
- UCD School of Medicine and Medical Science (SMMS), UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - Luke Gubbins
- UCD School of Medicine and Medical Science (SMMS), UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - Aoife Cannon
- Molecular Department of Surgery, Institute of Molecular Medicine, Trinity Centre for Health Sciences, St James's Hospital, Dublin 8, Ireland
| | - Daniel Sharpe
- School of Pharmacy, Queen's University of Belfast, Belfast, Northern Ireland, United Kingdom
| | - Jacintha O'Sullivan
- Molecular Department of Surgery, Institute of Molecular Medicine, Trinity Centre for Health Sciences, St James's Hospital, Dublin 8, Ireland
| | - Madeline Murphy
- UCD School of Medicine and Medical Science (SMMS), UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - Stephen F Madden
- Molecular Therapeutics for Cancer Ireland, National Institute for Cellular Biotechnology, Dublin City University, Glasnevin, Dublin 9, Ireland
| | - Malcolm Kell
- Department of Surgery, Mater Misericordiae University Hospital, Dublin 7, Ireland
| | - Amanda McCann
- UCD School of Medicine and Medical Science (SMMS), UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - Fiona Furlong
- School of Pharmacy, Queen's University of Belfast, Belfast, Northern Ireland, United Kingdom
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20
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Rizzo V, Richman J, Puthanveettil SV. Dissecting mechanisms of brain aging by studying the intrinsic excitability of neurons. Front Aging Neurosci 2015; 6:337. [PMID: 25610394 PMCID: PMC4285138 DOI: 10.3389/fnagi.2014.00337] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 11/29/2014] [Indexed: 01/30/2023] Open
Abstract
Several studies using vertebrate and invertebrate animal models have shown aging associated changes in brain function. Importantly, changes in soma size, loss or regression of dendrites and dendritic spines and alterations in the expression of neurotransmitter receptors in specific neurons were described. Despite this understanding, how aging impacts intrinsic properties of individual neurons or circuits that govern a defined behavior is yet to be determined. Here we discuss current understanding of specific electrophysiological changes in individual neurons and circuits during aging.
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Affiliation(s)
- Valerio Rizzo
- Department of Neuroscience, The Scripps Research Institute Jupiter, FL, USA
| | - Jeffrey Richman
- Department of Neuroscience, The Scripps Research Institute Jupiter, FL, USA
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21
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Herdegen S, Holmes G, Cyriac A, Calin-Jageman IE, Calin-Jageman RJ. Characterization of the rapid transcriptional response to long-term sensitization training in Aplysia californica. Neurobiol Learn Mem 2014; 116:27-35. [PMID: 25117657 DOI: 10.1016/j.nlm.2014.07.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/17/2014] [Accepted: 07/24/2014] [Indexed: 11/24/2022]
Abstract
We used a custom-designed microarray and quantitative PCR to characterize the rapid transcriptional response to long-term sensitization training in the marine mollusk Aplysia californica. Aplysia were exposed to repeated noxious shocks to one side of the body, a procedure known to induce a long-lasting, transcription-dependent increase in reflex responsiveness that is restricted to the side of training. One hour after training, pleural ganglia from the trained and untrained sides of the body were harvested; these ganglia contain the sensory nociceptors which help mediate the expression of long-term sensitization memory. Microarray analysis from 8 biological replicates suggests that long-term sensitization training rapidly regulates at least 81 transcripts. We used qPCR to test a subset of these transcripts and found that 83% were confirmed in the same samples, and 86% of these were again confirmed in an independent sample. Thus, our new microarray design shows strong convergent and predictive validity for analyzing the transcriptional correlates of memory in Aplysia. Fully validated transcripts include some previously identified as regulated in this paradigm (ApC/EBP and ApEgr) but also include novel findings. Specifically, we show that long-term sensitization training rapidly up-regulates the expression of transcripts which may encode Aplysia homologs of a C/EBPγ transcription factor, a glycine transporter (GlyT2), and a vacuolar-protein-sorting-associated protein (VPS36).
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Affiliation(s)
- Samantha Herdegen
- Neuroscience Program, Dominican University, River Forest, IL, United States
| | - Geraldine Holmes
- Neuroscience Program, Dominican University, River Forest, IL, United States
| | - Ashly Cyriac
- Neuroscience Program, Dominican University, River Forest, IL, United States
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22
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Kempsell AT, Fieber LA. Behavioral aging is associated with reduced sensory neuron excitability in Aplysia californica. Front Aging Neurosci 2014; 6:84. [PMID: 24847260 PMCID: PMC4023074 DOI: 10.3389/fnagi.2014.00084] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 04/22/2014] [Indexed: 11/16/2022] Open
Abstract
Invertebrate models have advantages for understanding the basis of behavioral aging due to their simple nervous systems and short lifespans. The potential usefulness of Aplysia californica in aging research is apparent from its long history of neurobiological research, but it has been underexploited in this model use. Aging of simple reflexes at both single sensory neuron and neural circuit levels was studied to connect behavioral aging to neurophysiological aging. The tail withdrawal reflex (TWR), righting reflex, and biting response were measured throughout sexual maturity in 3 cohorts of hatchery-reared animals of known age. Reflex times increased and reflex amplitudes decreased significantly during aging. Aging in sensory neurons of animals with deficits in measures of the TWR and biting response resulted in significantly reduced excitability in old animals compared to their younger siblings. The threshold for firing increased while the number of action potentials in response to depolarizing current injection decreased during aging in sensory neurons, but not in tail motoneurons. Glutamate receptor-activated responses in sensory neurons also decreased with aging. In old tail motoneurons, the amplitude of evoked EPSPs following tail shock decreased, presumably due to reduced sensory neuron excitability during aging. The results were used to develop stages of aging relevant to both hatchery-reared and wild-caught Aplysia. Aplysia is a viable aging model in which the contributions of differential aging of components of neural circuits may be assessed.
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Affiliation(s)
- Andrew T Kempsell
- Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami Miami, FL, USA
| | - Lynne A Fieber
- Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami Miami, FL, USA
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23
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Kadakkuzha BM, Liu XA, Narvaez M, Kaye A, Akhmedov K, Puthanveettil SV. Asymmetric localization of natural antisense RNA of neuropeptide sensorin in Aplysia sensory neurons during aging and activity. Front Genet 2014; 5:84. [PMID: 24795747 PMCID: PMC4001032 DOI: 10.3389/fgene.2014.00084] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 03/29/2014] [Indexed: 11/21/2022] Open
Abstract
Despite the advances in our understanding of transcriptome, regulation and function of its non-coding components continue to be poorly understood. Here we searched for natural antisense transcript for sensorin (NAT-SRN), a neuropeptide expressed in the presynaptic sensory neurons of gill-withdrawal reflex of the marine snail Aplysia californica. Sensorin (SRN) has a key role in learning and long-term memory storage in Aplysia. We have now identified NAT-SRN in the central nervous system (CNS) and have confirmed its expression by northern blotting and fluorescent RNA in situ hybridization. Quantitative analysis of NAT-SRN in micro-dissected cell bodies and processes of sensory neurons suggest that NAT-SRN is present in the distal neuronal processes along with sense transcripts. Importantly, aging is associated with reduction in levels of NAT-SRN in sensory neuron processes. Furthermore, we find that forskolin, an activator of CREB signaling, differentially alters the distribution of SRN and NAT-SRN. These studies reveal novel insights into physiological regulation of natural antisense RNAs.
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Affiliation(s)
- Beena M Kadakkuzha
- Department of Neuroscience, The Scripps Research Institute Jupiter, FL, USA
| | - Xin-An Liu
- Department of Neuroscience, The Scripps Research Institute Jupiter, FL, USA
| | - Maria Narvaez
- Department of Neuroscience, The Scripps Research Institute Jupiter, FL, USA
| | - Alexandra Kaye
- Department of Neuroscience, The Scripps Research Institute Jupiter, FL, USA
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