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Barber KR, Vizcarra VS, Zilch A, Majuta L, Diezel CC, Culver OP, Hughes BW, Taniguchi M, Streicher JM, Vanderah TW, Riegel AC. The Role of Ryanodine Receptor 2 in Drug-Associated Learning. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.03.560743. [PMID: 37873212 PMCID: PMC10592901 DOI: 10.1101/2023.10.03.560743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Type-2 ryanodine receptor (RyR2) ion channels facilitate the release of Ca 2+ from stores and serve an important function in neuroplasticity. The role for RyR2 in hippocampal-dependent learning and memory is well established and chronic hyperphosphorylation of RyR2 (RyR2P) is associated with pathological calcium leakage and cognitive disorders, including Alzheimer's disease. By comparison, little is known about the role of RyR2 in the ventral medial prefrontal cortex (vmPFC) circuitry important for working memory, decision making, and reward seeking. Here, we evaluated the basal expression and localization of RyR2 and RyR2P in the vmPFC. Next, we employed an operant model of sucrose, cocaine, or morphine self-administration (SA) followed by a (reward-free) recall test, to reengage vmPFC neurons and reactivate reward-seeking and re-evaluated the expression and localization of RyR2 and RyR2P in vmPFC. Under basal conditions, RyR2 was expressed in pyramidal cells but not regularly detected in PV/SST interneurons. On the contrary, RyR2P was rarely observed in PFC somata and was restricted to a different subcompartment of the same neuron - the apical dendrites of layer-5 pyramidal cells. Chronic SA of drug (cocaine or morphine) and nondrug (sucrose) rewards produced comparable increases in RyR2 protein expression. However, recalling either drug reward impaired the usual localization of RyR2P in dendrites and markedly increased its expression in somata immunoreactive for Fos, a marker of highly activated neurons. These effects could not be explained by chronic stress or drug withdrawal and instead appeared to require a recall experience associated with prior drug SA. In addition to showing the differential distribution of RyR2/RyR2P and affirming the general role of vmPFC in reward learning, this study provides information on the propensity of addictive drugs to redistribute RyR2P ion channels in a neuronal population engaged in drug-seeking. Hence, focusing on the early impact of addictive drugs on RyR2 function may serve as a promising approach to finding a treatment for substance use disorders.
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Moss RM, Sorajja N, Mills LJ, Moertel CL, Hoang TT, Spector LG, Largaespada DA, Williams LA. Sex differences in methylation profiles are apparent in medulloblastoma, particularly among SHH tumors. Front Oncol 2023; 13:1113121. [PMID: 37035203 PMCID: PMC10080161 DOI: 10.3389/fonc.2023.1113121] [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: 12/01/2022] [Accepted: 03/15/2023] [Indexed: 04/11/2023] Open
Abstract
Background Medulloblastoma, the most common malignant pediatric brain tumor, displays marked sex differences in prevalence of the four main molecular subgroups: SHH, WNT, Group 3 and Group 4. Males are more frequently diagnosed with SHH, Group 3 and 4 tumors, which have worse prognoses than WNT tumors. Little is known about sex differences in methylation profiles within subgroups. Methods Using publicly available methylation data (Illumina HumanMethylation450K array), we compared beta values for males versus females. Differentially methylated positions (DMP) by sex within medulloblastoma subgroups were identified on the autosomes. DMPs were mapped to genes and Reactome pathway analysis was run by subgroup. Kaplan-Meier survival curves (Log-Rank p-values) were assessed for each sex within subgroup. MethylCIBERSORT was used to investigate the tumor microenvironment using deconvolution to estimate the abundances of immune cell types using DNA methylation data. Results There were statistically significant differences in sex by medulloblastoma subgroups (chi-squared p-value=0.00004): Group 3 (n=144; 65% male), Group 4 (n=326; 67% male), SHH (n=223; 57% male) and WNT (n=70; 41% male). Females had worse survival than males for SHH (p-value=0.02). DMPs by sex were identified within subgroups: SHH (n=131), Group 4 (n=29), Group 3 (n=19), and WNT (n=16) and validated in an independent dataset. Unsupervised hierarchical clustering showed that sex-DMPs in SHH did not correlate with other tumor attributes. Ten genes with sex DMPs (RFTN1, C1orf103, FKBP1B, COL25A1, NPDC1, B3GNT1, FOXN3, RNASEH2C, TLE1, and PHF17) were shared across subgroups. Significant pathways (p<0.05) associated with DMPs were identified for SHH (n=22) and Group 4 (n=4) and included signaling pathways for RET proto-oncogene, advanced glycosylation end product receptor, regulation of KIT, neurotrophic receptors, NOTCH, and TGF-β. In SHH, we identified DMPs in four genes (CDK6, COL25A1, MMP16, PRIM2) that encode proteins which are the target of therapies in clinical trials for other cancers. There were few sex differences in immune cell composition within tumor subgroups. Conclusion There are sexually dimorphic methylation profiles for SHH medulloblastoma where survival differences were observed. Sex-specific therapies in medulloblastoma may impact outcomes.
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Affiliation(s)
- Rachel M. Moss
- Division of Epidemiology & Clinical Research, Department of Pediatrics, University of Minnesota, Minneapolis, MN, United States
- Bioinformatics and Computational Biology, University of Minnesota, Minneapolis, MN, United States
| | - Natali Sorajja
- Division of Epidemiology & Clinical Research, Department of Pediatrics, University of Minnesota, Minneapolis, MN, United States
- Macalester College, St. Paul, MN, United States
| | - Lauren J. Mills
- Division of Epidemiology & Clinical Research, Department of Pediatrics, University of Minnesota, Minneapolis, MN, United States
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, United States
| | - Christopher L. Moertel
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, United States
- Pediatric Hematology and Oncology, Department of Pediatrics, University of Minnesota, Minneapolis, MN, United States
- Brain Tumor Program, University of Minnesota, Minneapolis, MN, United States
| | - Thanh T. Hoang
- Department of Pediatrics, Division of Hematology-Oncology, Baylor College of Medicine, Houston, TX, United States
- Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, United States
- Cancer and Hematology Center, Texas Children’s Hospital, Houston, TX, United States
| | - Logan G. Spector
- Division of Epidemiology & Clinical Research, Department of Pediatrics, University of Minnesota, Minneapolis, MN, United States
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, United States
| | - David A. Largaespada
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, United States
- Brain Tumor Program, University of Minnesota, Minneapolis, MN, United States
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, United States
- Department of Genetics, Cell Biology and Development, University of Minnesota School of Medicine, Minneapolis, MN, United States
- Center for Genome Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Lindsay A. Williams
- Division of Epidemiology & Clinical Research, Department of Pediatrics, University of Minnesota, Minneapolis, MN, United States
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, United States
- Brain Tumor Program, University of Minnesota, Minneapolis, MN, United States
- *Correspondence: Lindsay A. Williams,
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Mustaly-Kalimi S, Gallegos W, Marr RA, Gilman-Sachs A, Peterson DA, Sekler I, Stutzmann GE. Protein mishandling and impaired lysosomal proteolysis generated through calcium dysregulation in Alzheimer's disease. Proc Natl Acad Sci U S A 2022; 119:e2211999119. [PMID: 36442130 PMCID: PMC9894236 DOI: 10.1073/pnas.2211999119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 10/27/2022] [Indexed: 11/29/2022] Open
Abstract
Impairments in neural lysosomal- and autophagic-mediated degradation of cellular debris contribute to neuritic dystrophy and synaptic loss. While these are well-characterized features of neurodegenerative disorders such as Alzheimer's disease (AD), the upstream cellular processes driving deficits in pathogenic protein mishandling are less understood. Using a series of fluorescent biosensors and optical imaging in model cells, AD mouse models and human neurons derived from AD patients, we reveal a previously undescribed cellular signaling cascade underlying protein mishandling mediated by intracellular calcium dysregulation, an early component of AD pathogenesis. Increased Ca2+ release via the endoplasmic reticulum (ER)-resident ryanodine receptor (RyR) is associated with reduced expression of the lysosome proton pump vacuolar-ATPase (vATPase) subunits (V1B2 and V0a1), resulting in lysosome deacidification and disrupted proteolytic activity in AD mouse models and human-induced neurons (HiN). As a result of impaired lysosome digestive capacity, mature autophagosomes with hyperphosphorylated tau accumulated in AD murine neurons and AD HiN, exacerbating proteinopathy. Normalizing AD-associated aberrant RyR-Ca2+ signaling with the negative allosteric modulator, dantrolene (Ryanodex), restored vATPase levels, lysosomal acidification and proteolytic activity, and autophagic clearance of intracellular protein aggregates in AD neurons. These results highlight that prior to overt AD histopathology or cognitive deficits, aberrant upstream Ca2+ signaling disrupts lysosomal acidification and contributes to pathological accumulation of intracellular protein aggregates. Importantly, this is demonstrated in animal models of AD, and in human iPSC-derived neurons from AD patients. Furthermore, pharmacological suppression of RyR-Ca2+ release rescued proteolytic function, revealing a target for therapeutic intervention that has demonstrated effects in clinically-relevant assays.
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Affiliation(s)
- Sarah Mustaly-Kalimi
- Center for Neurodegenerative Disease and Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL60064
| | - Wacey Gallegos
- Center for Neurodegenerative Disease and Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL60064
| | - Robert A. Marr
- Center for Neurodegenerative Disease and Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL60064
| | - Alice Gilman-Sachs
- Center for Cancer Cell Biology, Immunology and Infection, Rosalind Franklin University of Medicine and Science, Immunology, and Infection, North Chicago, IL60064
| | - Daniel A. Peterson
- Center for Neurodegenerative Disease and Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL60064
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Science and Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva84105, Israel
| | - Grace E. Stutzmann
- Center for Neurodegenerative Disease and Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL60064
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Di Benedetto G, Iannucci LF, Surdo NC, Zanin S, Conca F, Grisan F, Gerbino A, Lefkimmiatis K. Compartmentalized Signaling in Aging and Neurodegeneration. Cells 2021; 10:cells10020464. [PMID: 33671541 PMCID: PMC7926881 DOI: 10.3390/cells10020464] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 12/12/2022] Open
Abstract
The cyclic AMP (cAMP) signalling cascade is necessary for cell homeostasis and plays important roles in many processes. This is particularly relevant during ageing and age-related diseases, where drastic changes, generally decreases, in cAMP levels have been associated with the progressive decline in overall cell function and, eventually, the loss of cellular integrity. The functional relevance of reduced cAMP is clearly supported by the finding that increases in cAMP levels can reverse some of the effects of ageing. Nevertheless, despite these observations, the molecular mechanisms underlying the dysregulation of cAMP signalling in ageing are not well understood. Compartmentalization is widely accepted as the modality through which cAMP achieves its functional specificity; therefore, it is important to understand whether and how this mechanism is affected during ageing and to define which is its contribution to this process. Several animal models demonstrate the importance of specific cAMP signalling components in ageing, however, how age-related changes in each of these elements affect the compartmentalization of the cAMP pathway is largely unknown. In this review, we explore the connection of single components of the cAMP signalling cascade to ageing and age-related diseases whilst elaborating the literature in the context of cAMP signalling compartmentalization.
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Affiliation(s)
- Giulietta Di Benedetto
- Neuroscience Institute, National Research Council of Italy (CNR), 35121 Padova, Italy;
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; (L.F.I.); (S.Z.); (F.C.); (F.G.)
- Correspondence: (G.D.B.); (K.L.)
| | - Liliana F. Iannucci
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; (L.F.I.); (S.Z.); (F.C.); (F.G.)
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
| | - Nicoletta C. Surdo
- Neuroscience Institute, National Research Council of Italy (CNR), 35121 Padova, Italy;
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; (L.F.I.); (S.Z.); (F.C.); (F.G.)
| | - Sofia Zanin
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; (L.F.I.); (S.Z.); (F.C.); (F.G.)
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
| | - Filippo Conca
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; (L.F.I.); (S.Z.); (F.C.); (F.G.)
- Department of Biology, University of Padova, 35122 Padova, Italy
| | - Francesca Grisan
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; (L.F.I.); (S.Z.); (F.C.); (F.G.)
- Department of Biology, University of Padova, 35122 Padova, Italy
| | - Andrea Gerbino
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, 70121 Bari, Italy;
| | - Konstantinos Lefkimmiatis
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; (L.F.I.); (S.Z.); (F.C.); (F.G.)
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
- Correspondence: (G.D.B.); (K.L.)
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Calcium-induced calcium release and type 3 ryanodine receptors modulate the slow afterhyperpolarising current, sIAHP, and its potentiation in hippocampal pyramidal neurons. PLoS One 2020; 15:e0230465. [PMID: 32559219 PMCID: PMC7304577 DOI: 10.1371/journal.pone.0230465] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 06/03/2020] [Indexed: 12/21/2022] Open
Abstract
The slow afterhyperpolarising current, sIAHP, is a Ca2+-dependent current that plays an important role in the late phase of spike frequency adaptation. sIAHP is activated by voltage-gated Ca2+ channels, while the contribution of calcium from ryanodine-sensitive intracellular stores, released by calcium-induced calcium release (CICR), is controversial in hippocampal pyramidal neurons. Three types of ryanodine receptors (RyR1-3) are expressed in the hippocampus, with RyR3 showing a predominant expression in CA1 neurons. We investigated the specific role of CICR, and particularly of its RyR3-mediated component, in the regulation of the sIAHP amplitude and time course, and the activity-dependent potentiation of the sIAHP in rat and mouse CA1 pyramidal neurons. Here we report that enhancement of CICR by caffeine led to an increase in sIAHP amplitude, while inhibition of CICR by ryanodine caused a small, but significant reduction of sIAHP. Inhibition of ryanodine-sensitive Ca2+ stores by ryanodine or depletion by the SERCA pump inhibitor cyclopiazonic acid caused a substantial attenuation in the sIAHP activity-dependent potentiation in both rat and mouse CA1 pyramidal neurons. Neurons from mice lacking RyR3 receptors exhibited a sIAHP with features undistinguishable from wild-type neurons, which was similarly reduced by ryanodine. However, the lack of RyR3 receptors led to a faster and reduced activity-dependent potentiation of sIAHP. We conclude that ryanodine receptor-mediated CICR contributes both to the amplitude of the sIAHP at steady state and its activity-dependent potentiation in rat and mouse hippocampal pyramidal neurons. In particular, we show that RyR3 receptors play an essential and specific role in shaping the activity-dependent potentiation of the sIAHP. The modulation of activity-dependent potentiation of sIAHP by RyR3-mediated CICR contributes to plasticity of intrinsic neuronal excitability and is likely to play a critical role in higher cognitive functions, such as learning and memory.
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6
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Han RW, Liu ZP, Lin HR, Tian AW, Xiao YF, Wei J, Deng KY, Pan BX, Xin HB. Role of lateral amygdala calstabin2 in regulation of fear memory. Mol Brain 2020; 13:35. [PMID: 32151269 PMCID: PMC7063811 DOI: 10.1186/s13041-020-00576-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 03/02/2020] [Indexed: 01/28/2023] Open
Abstract
Calstabin2, also named FK506 binding protein 12.6 (FKBP12.6), is a subunit of ryanodine receptor subtype 2 (RyR2) macromolecular complex, an intracellular calcium channel. Studies from our and other's lab have shown that hippocampal calstabin2 regulates spatial memory. Calstabin2 and RyR2 are widely distributed in the brain, including the amygdala, a key brain area involved in the regulation of emotion including fear. Little is known about the role of calstabin2 in fear memory. Here, we found that genetic deletion of calstabin2 impaired long-term memory in cued fear conditioning test. Knockdown calstabin2 in the lateral amygdala (LA) by viral vector also impaired long-term cued fear memory expression. Furthermore, calstabin2 knockout reduced long-term potentiation (LTP) at both cortical and thalamic inputs to the LA. In conclusion, our present data indicate that calstabin2 in the LA plays a crucial role in the regulating of emotional memory.
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Affiliation(s)
- Ren-Wen Han
- The National Engineering Research Center for Bioengineering Drugs and the Technologies, Institute of Translational Medicine, Nanchang University, Nanchang, China. .,Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang, China.
| | - Zhi-Peng Liu
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang, China
| | - Hong-Ru Lin
- The National Engineering Research Center for Bioengineering Drugs and the Technologies, Institute of Translational Medicine, Nanchang University, Nanchang, China
| | - Ao-Wen Tian
- The National Engineering Research Center for Bioengineering Drugs and the Technologies, Institute of Translational Medicine, Nanchang University, Nanchang, China
| | - Yun-Fei Xiao
- The National Engineering Research Center for Bioengineering Drugs and the Technologies, Institute of Translational Medicine, Nanchang University, Nanchang, China
| | - Jie Wei
- Department of Physiology, Medical College of Nanchang University, Nanchang, China
| | - Ke-Yu Deng
- The National Engineering Research Center for Bioengineering Drugs and the Technologies, Institute of Translational Medicine, Nanchang University, Nanchang, China
| | - Bing-Xing Pan
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang, China.
| | - Hong-Bo Xin
- The National Engineering Research Center for Bioengineering Drugs and the Technologies, Institute of Translational Medicine, Nanchang University, Nanchang, China. .,College of Life Sciences, Nanchang University, Nanchang, China.
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7
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Ibañez S, Luebke JI, Chang W, Draguljić D, Weaver CM. Network Models Predict That Pyramidal Neuron Hyperexcitability and Synapse Loss in the dlPFC Lead to Age-Related Spatial Working Memory Impairment in Rhesus Monkeys. Front Comput Neurosci 2020; 13:89. [PMID: 32009920 PMCID: PMC6979278 DOI: 10.3389/fncom.2019.00089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 12/18/2019] [Indexed: 01/04/2023] Open
Abstract
Behavioral studies have shown spatial working memory impairment with aging in several animal species, including humans. Persistent activity of layer 3 pyramidal dorsolateral prefrontal cortex (dlPFC) neurons during delay periods of working memory tasks is important for encoding memory of the stimulus. In vitro studies have shown that these neurons undergo significant age-related structural and functional changes, but the extent to which these changes affect neural mechanisms underlying spatial working memory is not understood fully. Here, we confirm previous studies showing impairment on the Delayed Recognition Span Task in the spatial condition (DRSTsp), and increased in vitro action potential firing rates (hyperexcitability), across the adult life span of the rhesus monkey. We use a bump attractor model to predict how empirically observed changes in the aging dlPFC affect performance on the Delayed Response Task (DRT), and introduce a model of memory retention in the DRSTsp. Persistent activity-and, in turn, cognitive performance-in both models was affected much more by hyperexcitability of pyramidal neurons than by a loss of synapses. Our DRT simulations predict that additional changes to the network, such as increased firing of inhibitory interneurons, are needed to account for lower firing rates during the DRT with aging reported in vivo. Synaptic facilitation was an essential feature of the DRSTsp model, but it did not compensate fully for the effects of the other age-related changes on DRT performance. Modeling pyramidal neuron hyperexcitability and synapse loss simultaneously led to a partial recovery of function in both tasks, with the simulated level of DRSTsp impairment similar to that observed in aging monkeys. This modeling work integrates empirical data across multiple scales, from synapse counts to cognitive testing, to further our understanding of aging in non-human primates.
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Affiliation(s)
- Sara Ibañez
- Department of Mathematics, Franklin and Marshall College, Lancaster, PA, United States
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - Jennifer I. Luebke
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - Wayne Chang
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States
| | - Danel Draguljić
- Department of Mathematics, Franklin and Marshall College, Lancaster, PA, United States
| | - Christina M. Weaver
- Department of Mathematics, Franklin and Marshall College, Lancaster, PA, United States
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Kumar A. Calcium Signaling During Brain Aging and Its Influence on the Hippocampal Synaptic Plasticity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:985-1012. [PMID: 31646542 DOI: 10.1007/978-3-030-12457-1_39] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Calcium (Ca2+) ions are highly versatile intracellular signaling molecules and are universal second messenger for regulating a variety of cellular and physiological functions including synaptic plasticity. Ca2+ homeostasis in the central nervous system endures subtle dysregulation with advancing age. Research has provided abundant evidence that brain aging is associated with altered neuronal Ca2+ regulation and synaptic plasticity mechanisms. Much of the work has focused on the hippocampus, a brain region critically involved in learning and memory, which is particularly susceptible to dysfunction during aging. The current chapter takes a specific perspective, assessing various Ca2+ sources and the influence of aging on Ca2+ sources and synaptic plasticity in the hippocampus. Integrating the knowledge of the complexity of age-related alterations in neuronal Ca2+ signaling and synaptic plasticity mechanisms will positively shape the development of highly effective therapeutics to treat brain disorders including cognitive impairment associated with aging and neurodegenerative disease.
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Affiliation(s)
- Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
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9
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Gant JC, Kadish I, Chen KC, Thibault O, Blalock EM, Porter NM, Landfield PW. Aging-Related Calcium Dysregulation in Rat Entorhinal Neurons Homologous with the Human Entorhinal Neurons in which Alzheimer's Disease Neurofibrillary Tangles First Appear. J Alzheimers Dis 2019; 66:1371-1378. [PMID: 30412490 PMCID: PMC6294592 DOI: 10.3233/jad-180618] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Aging is the leading risk factor for idiopathic Alzheimer’s disease (AD), indicating that normal aging processes promote AD and likely are present in the neurons in which AD pathogenesis originates. In AD, neurofibrillary tangles (NFTs) appear first in entorhinal cortex, implying that aging processes in entorhinal neurons promote NFT pathogenesis. Using electrophysiology and immunohistochemistry, we find pronounced aging-related Ca2 + dysregulation in rat entorhinal neurons homologous with the human neurons in which NFTs originate. Considering that humans recapitulate many aspects of animal brain aging, these results support the hypothesis that aging-related Ca2 + dysregulation occurs in human entorhinal neurons and promotes NFT pathogenesis.
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Affiliation(s)
- John C Gant
- Department of Pharmacology & Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Inga Kadish
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Kuey-Chu Chen
- Department of Pharmacology & Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Olivier Thibault
- Department of Pharmacology & Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Eric M Blalock
- Department of Pharmacology & Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Nada M Porter
- Department of Pharmacology & Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Philip W Landfield
- Department of Pharmacology & Nutritional Sciences, University of Kentucky, Lexington, KY, USA
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10
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Foster TC. Senescent neurophysiology: Ca 2+ signaling from the membrane to the nucleus. Neurobiol Learn Mem 2019; 164:107064. [PMID: 31394200 DOI: 10.1016/j.nlm.2019.107064] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/29/2019] [Accepted: 08/03/2019] [Indexed: 12/16/2022]
Abstract
The current review provides a historical perspective on the evolution of hypothesized mechanisms for senescent neurophysiology, focused on the CA1 region of the hippocampus, and the relationship of senescent neurophysiology to impaired hippocampal-dependent memory. Senescent neurophysiology involves processes linked to calcium (Ca2+) signaling including an increase in the Ca2+-dependent afterhyperpolarization (AHP), decreasing pyramidal cell excitability, hyporesponsiveness of N-methyl-D-aspartate (NMDA) receptor function, and a shift in Ca2+-dependent synaptic plasticity. Dysregulation of intracellular Ca2+ and downstream signaling of kinase and phosphatase activity lies at the core of senescent neurophysiology. Ca2+-dysregulation involves a decrease in Ca2+ influx through NMDA receptors and an increase release of Ca2+ from internal Ca2+ stores. Recent work has identified changes in redox signaling, arising in middle-age, as an initiating factor for senescent neurophysiology. The shift in redox state links processes of aging, oxidative stress and inflammation, with functional changes in mechanisms required for episodic memory. The link between age-related changes in Ca2+ signaling, epigenetics and gene expression is an exciting area of research. Pharmacological and behavioral intervention, initiated in middle-age, can promote memory function by initiating transcription of neuroprotective genes and rejuvenating neurophysiology. However, with more advanced age, or under conditions of neurodegenerative disease, epigenetic changes may weaken the link between environmental influences and transcription, decreasing resilience of memory function.
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Affiliation(s)
- Thomas C Foster
- Department of Neuroscience and Genetics and Genomics Program, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA.
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11
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Kuznik BI, Davydov SO, Popravka ES, Lin’kova NS, Kozina LS, Khavinson VK. Epigenetic Mechanisms of Peptide-Driven Regulation and Neuroprotective Protein FKBP1b. Mol Biol 2019. [DOI: 10.1134/s0026893319020092] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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12
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Non-linear calcium signalling and synaptic plasticity in interneurons. Curr Opin Neurobiol 2019; 54:98-103. [DOI: 10.1016/j.conb.2018.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 09/18/2018] [Accepted: 09/19/2018] [Indexed: 01/24/2023]
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FK506-Binding Protein 12.6/1b, a Negative Regulator of [Ca 2+], Rescues Memory and Restores Genomic Regulation in the Hippocampus of Aging Rats. J Neurosci 2017; 38:1030-1041. [PMID: 29255009 PMCID: PMC5783960 DOI: 10.1523/jneurosci.2234-17.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/10/2017] [Accepted: 11/24/2017] [Indexed: 12/20/2022] Open
Abstract
Hippocampal overexpression of FK506-binding protein 12.6/1b (FKBP1b), a negative regulator of ryanodine receptor Ca2+ release, reverses aging-induced memory impairment and neuronal Ca2+ dysregulation. Here, we tested the hypothesis that FKBP1b also can protect downstream transcriptional networks from aging-induced dysregulation. We gave hippocampal microinjections of FKBP1b-expressing viral vector to male rats at either 13 months of age (long-term, LT) or 19 months of age (short-term, ST) and tested memory performance in the Morris water maze at 21 months of age. Aged rats treated ST or LT with FKBP1b substantially outperformed age-matched vector controls and performed similarly to each other and young controls (YCs). Transcriptional profiling in the same animals identified 2342 genes with hippocampal expression that was upregulated/downregulated in aged controls (ACs) compared with YCs (the aging effect). Of these aging-dependent genes, 876 (37%) also showed altered expression in aged FKBP1b-treated rats compared with ACs, with FKBP1b restoring expression of essentially all such genes (872/876, 99.5%) in the direction opposite the aging effect and closer to levels in YCs. This inverse relationship between the aging and FKBP1b effects suggests that the aging effects arise from FKBP1b deficiency. Functional category analysis revealed that genes downregulated with aging and restored by FKBP1b were associated predominantly with diverse brain structure categories, including cytoskeleton, membrane channels, and extracellular region. Conversely, genes upregulated with aging but not restored by FKBP1b associated primarily with glial–neuroinflammatory, ribosomal, and lysosomal categories. Immunohistochemistry confirmed aging-induced rarefaction and FKBP1b-mediated restoration of neuronal microtubular structure. Therefore, a previously unrecognized genomic network modulating diverse brain structural processes is dysregulated by aging and restored by FKBP1b overexpression. SIGNIFICANCE STATEMENT Previously, we found that hippocampal overexpression of FK506-binding protein 12.6/1b (FKBP1b), a negative regulator of intracellular Ca2+ responses, reverses both aging-related Ca2+ dysregulation and cognitive impairment. Here, we tested whether hippocampal FKBP1b overexpression also counteracts aging changes in gene transcriptional networks. In addition to reducing memory deficits in aged rats, FKBP1b selectively counteracted aging-induced expression changes in 37% of aging-dependent genes, with cytoskeletal and extracellular structure categories highly associated with the FKBP1b-rescued genes. Our results indicate that, in parallel with cognitive processes, a novel transcriptional network coordinating brain structural organization is dysregulated with aging and restored by FKBP1b.
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Maimaiti S, Frazier HN, Anderson KL, Ghoweri AO, Brewer LD, Porter NM, Thibault O. Novel calcium-related targets of insulin in hippocampal neurons. Neuroscience 2017; 364:130-142. [PMID: 28939258 DOI: 10.1016/j.neuroscience.2017.09.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 09/07/2017] [Accepted: 09/08/2017] [Indexed: 01/28/2023]
Abstract
Both insulin signaling disruption and Ca2+ dysregulation are closely related to memory loss during aging and increase the vulnerability to Alzheimer's disease (AD). In hippocampal neurons, aging-related changes in calcium regulatory pathways have been shown to lead to higher intracellular calcium levels and an increase in the Ca2+-dependent afterhyperpolarization (AHP), which is associated with cognitive decline. Recent studies suggest that insulin reduces the Ca2+-dependent AHP. Given the sensitivity of neurons to insulin and evidence that brain insulin signaling is reduced with age, insulin-mediated alterations in calcium homeostasis may underlie the beneficial actions of insulin in the brain. Indeed, increasing insulin signaling in the brain via intranasal delivery has yielded promising results such as improving memory in both clinical and animal studies. However, while several mechanisms have been proposed, few have focused on regulation on intracellular Ca2+. In the present study, we further examined the effects of acute insulin on calcium pathways in primary hippocampal neurons in culture. Using the whole-cell patch-clamp technique, we found that acute insulin delivery reduced voltage-gated calcium currents. Fura-2 imaging was used to also address acute insulin effects on spontaneous and depolarization-mediated Ca2+ transients. Results indicate that insulin reduced Ca2+ transients, which appears to have involved a reduction in ryanodine receptor function. Together, these results suggest insulin regulates pathways that control intracellular Ca2+ which may reduce the AHP and improve memory. This may be one mechanism contributing to improved memory recall in response to intranasal insulin therapy in the clinic.
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Affiliation(s)
- Shaniya Maimaiti
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Hilaree N Frazier
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Katie L Anderson
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Adam O Ghoweri
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Lawrence D Brewer
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Nada M Porter
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Olivier Thibault
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States.
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15
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Abu-Omar N, Das J, Szeto V, Feng ZP. Neuronal Ryanodine Receptors in Development and Aging. Mol Neurobiol 2017; 55:1183-1192. [DOI: 10.1007/s12035-016-0375-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 12/28/2016] [Indexed: 01/09/2023]
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Oh MM, Simkin D, Disterhoft JF. Intrinsic Hippocampal Excitability Changes of Opposite Signs and Different Origins in CA1 and CA3 Pyramidal Neurons Underlie Aging-Related Cognitive Deficits. Front Syst Neurosci 2016; 10:52. [PMID: 27375440 PMCID: PMC4899460 DOI: 10.3389/fnsys.2016.00052] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 05/27/2016] [Indexed: 11/13/2022] Open
Abstract
Aging-related cognitive deficits have been attributed to dysfunction of neurons due to failures at synaptic or intrinsic loci, or both. Given the importance of the hippocampus for successful encoding of memory and that the main output of the hippocampus is via the CA1 pyramidal neurons, much of the research has been focused on identifying the aging-related changes of these CA1 pyramidal neurons. We and others have discovered that the postburst afterhyperpolarization (AHP) following a train of action potentials is greatly enlarged in CA1 pyramidal neurons of aged animals. This enlarged postburst AHP is a significant factor in reducing the intrinsic excitability of these neurons, and thus limiting their activity in the neural network during learning. Based on these data, it has largely been thought that aging-related cognitive deficits are attributable to reduced activity of pyramidal neurons. However, recent in vivo and ex vivo studies provide compelling evidence that aging-related deficits could also be due to a converse change in CA3 pyramidal neurons, which show increased activity with aging. In this review, we will incorporate these recent findings and posit that an interdependent dynamic dysfunctional change occurs within the hippocampal network, largely due to altered intrinsic excitability in CA1 and CA3 hippocampal pyramidal neurons, which ultimately leads to the aging-related cognitive deficits.
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Affiliation(s)
- M Matthew Oh
- Department of Physiology, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - Dina Simkin
- Department of Physiology, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - John F Disterhoft
- Department of Physiology, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
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17
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Hidalgo C, Arias-Cavieres A. Calcium, Reactive Oxygen Species, and Synaptic Plasticity. Physiology (Bethesda) 2016; 31:201-15. [DOI: 10.1152/physiol.00038.2015] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In this review article, we address how activity-dependent Ca2+ signaling is crucial for hippocampal synaptic/structural plasticity and discuss how changes in neuronal oxidative state affect Ca2+ signaling and synaptic plasticity. We also analyze current evidence indicating that oxidative stress and abnormal Ca2+ signaling contribute to age-related synaptic plasticity deterioration.
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Affiliation(s)
- Cecilia Hidalgo
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile; and
- Center of Molecular Studies of the Cell and Physiology and Biophysics Program, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Alejandra Arias-Cavieres
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile; and
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The ryanodine receptor provides high throughput Ca2+-release but is precisely regulated by networks of associated proteins: a focus on proteins relevant to phosphorylation. Biochem Soc Trans 2016; 43:426-33. [PMID: 26009186 DOI: 10.1042/bst20140297] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Once opened, ryanodine receptors (RyR) are efficient pathways for the release of Ca2+ from the endoplasmic/sarcoplasmic reticulum (ER/SR). The precise nature of the Ca2+-release event, however, requires fine-tuning for the specific process and type of cell involved. For example, the spatial organization of RyRs, the luminal [Ca2+] and the influence of soluble regulators that fluctuate under physiological and pathophysiological control mechanisms, all affect the amplitude and duration of RyR Ca2+ fluxes. Various proteins are docked tightly to the huge bulky structure of RyR and there is growing evidence that, together, they provide a sophisticated and integrated system for regulating RyR channel gating. This review focuses on those proteins that are relevant to phosphorylation of RyR channels with particular reference to the cardiac isoform of RyR (RyR2). How phosphorylation of RyR affects channel activity and whether proteins such as the FK-506 binding proteins (FKBP12 and FKBP12.6) are involved, have been highly controversial subjects for more than a decade. But that is expected given the large number of participating proteins, the relevance of phosphorylation in heart failure and inherited arrhythmic diseases, and the frustrations of predicting relationships between structure and function before the advent of a high resolution structure of RyR.
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Abstract
TOR (target of rapamycin) and its mammalian ortholog mTOR have been discovered in an effort to understand the mechanisms of action of the immunosuppressant drug rapamycin extracted from a bacterium of the Easter Island (Rapa Nui) soil. mTOR is a serine/threonine kinase found in two functionally distinct complexes, mTORC1 and mTORC2, which are differentially regulated by a great number of nutrients such as glucose and amino acids, energy (oxygen and ATP/AMP content), growth factors, hormones, and neurotransmitters. mTOR controls many basic cellular functions such as protein synthesis, energy metabolism, cell size, lipid metabolism, autophagy, mitochondria, and lysosome biogenesis. In addition, mTOR-controlled signaling pathways regulate many integrated physiological functions of the nervous system including neuronal development, synaptic plasticity, memory storage, and cognition. Thus it is not surprising that deregulation of mTOR signaling is associated with many neurological and psychiatric disorders. Preclinical and preliminary clinical studies indicate that inhibition of mTORC1 can be beneficial for some pathological conditions such as epilepsy, cognitive impairment, and brain tumors, whereas stimulation of mTORC1 (direct or indirect) can be beneficial for other pathologies such as depression or axonal growth and regeneration.
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Affiliation(s)
- Joël Bockaert
- Centre National de la Recherche Scientifique, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier, France; Institut National de la Santé et de la Recherche Médicale U1191, Montpellier, France; and Université de Montpellier, UMR-5203, Montpellier, France
| | - Philippe Marin
- Centre National de la Recherche Scientifique, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier, France; Institut National de la Santé et de la Recherche Médicale U1191, Montpellier, France; and Université de Montpellier, UMR-5203, Montpellier, France
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Jang YJ, Jung CH, Ahn J, Gwon SY, Ha TY. Shikonin inhibits adipogenic differentiation via regulation of mir-34a-FKBP1B. Biochem Biophys Res Commun 2015; 467:941-7. [PMID: 26471303 DOI: 10.1016/j.bbrc.2015.10.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 10/08/2015] [Indexed: 10/22/2022]
Abstract
Shikonin is a naturally occurring naphthoquinone pigment and a major constituent present in Lithospermum erythrorhizon. Since microRNAs (miRNAs) are one of the key post-transcriptional regulators of adipogenesis, their manipulation represents a potential new strategy to inhibit adipogenesis. Our aim was to investigate shikonin-dependent inhibition of adipogenesis with an emphasis on miRNA-related processes. Mir-34a increased during induced adipogenesis, and this was suppressed in the presence of shikonin. mRNA expression of FKBP1B, a suggested target of mir-34a according to bioinformatics studies, decreased during adipogenesis, but was recovered by shikonin treatment, which reversely correlated with mir-34a expression. A mir-34a inhibitor suppressed MDI-induced adipogenesis by blocking PPARγ and C/EBPα expression, while suppression of mir-34a recovered MDI-induced down-regulation of FKBP1B expression. A mir-34a mimic decreased FKBP1B mRNA expression in 3T3-L1 preadipocytes. We also observed that mir-34a bound directly to the 3'-untranslated region of FKBP1B. Finally, FKBP1B overexpression attenuated MDI-induced adipogenesis, PPARγ, and C/EBPα expression. These results suggest that mir-34a regulates adipogenesis by targeting FKBP1B expression. Our findings reveal that shikonin prevents adipogenesis by blocking the mir-34a-FKBP1B pathway which represents a promising potential target for preventing obesity.
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Affiliation(s)
- Young Jin Jang
- Metabolic Mechanism Research Group, Korea Food Research Institute, Seongnam, Republic of Korea
| | - Chang Hwa Jung
- Metabolic Mechanism Research Group, Korea Food Research Institute, Seongnam, Republic of Korea; Division of Food Biotechnology, University of Science and Technology, Daejeon, Republic of Korea
| | - Jiyun Ahn
- Metabolic Mechanism Research Group, Korea Food Research Institute, Seongnam, Republic of Korea; Division of Food Biotechnology, University of Science and Technology, Daejeon, Republic of Korea
| | - So Young Gwon
- Metabolic Mechanism Research Group, Korea Food Research Institute, Seongnam, Republic of Korea
| | - Tae Youl Ha
- Metabolic Mechanism Research Group, Korea Food Research Institute, Seongnam, Republic of Korea; Division of Food Biotechnology, University of Science and Technology, Daejeon, Republic of Korea.
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21
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Reversal of Aging-Related Neuronal Ca2+ Dysregulation and Cognitive Impairment by Delivery of a Transgene Encoding FK506-Binding Protein 12.6/1b to the Hippocampus. J Neurosci 2015. [PMID: 26224869 DOI: 10.1523/jneurosci.1248-15.2015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED Brain Ca2+ regulatory processes are altered during aging, disrupting neuronal, and cognitive functions. In hippocampal pyramidal neurons, the Ca2+ -dependent slow afterhyperpolarization (sAHP) exhibits an increase with aging, which correlates with memory impairment. The increased sAHP results from elevated L-type Ca2+ channel activity and ryanodine receptor (RyR)-mediated Ca2+ release, but underlying molecular mechanisms are poorly understood. Previously, we found that expression of the gene encoding FK506-binding protein 12.6/1b (FKBP1b), a small immunophilin that stabilizes RyR-mediated Ca2+ release in cardiomyocytes, declines in hippocampus of aged rats and Alzheimer's disease subjects. Additionally, knockdown/disruption of hippocampal FKBP1b in young rats augments neuronal Ca2+ responses. Here, we test the hypothesis that declining FKBP1b underlies aging-related hippocampal Ca2+ dysregulation. Using microinjection of adeno-associated viral vector bearing a transgene encoding FKBP1b into the hippocampus of aged male rats, we assessed the critical prediction that overexpressing FKBP1b should reverse Ca2+ -mediated manifestations of brain aging. Immunohistochemistry and qRT-PCR confirmed hippocampal FKBP1b overexpression 4-6 weeks after injection. Compared to aged vector controls, aged rats overexpressing FKBP1b showed dramatic enhancement of spatial memory, which correlated with marked reduction of sAHP magnitude. Furthermore, simultaneous electrophysiological recording and Ca2+ imaging in hippocampal neurons revealed that the sAHP reduction was associated with a decrease in parallel RyR-mediated Ca2+ transients. Thus, hippocampal FKBP1b overexpression reversed key aspects of Ca2+ dysregulation and cognitive impairment in aging rats, supporting the novel hypothesis that declining FKBP1b is a molecular mechanism underlying aging-related Ca2+ dysregulation and unhealthy brain aging and pointing to FKBP1b as a potential therapeutic target. SIGNIFICANCE STATEMENT This paper reports critical tests of a novel hypothesis that proposes a molecular mechanism of unhealthy brain aging and possibly, Alzheimer's disease. For more than 30 years, evidence has been accumulating that brain aging is associated with dysregulation of calcium in neurons. Recently, we found that FK506-binding protein 12.6/1b (FKBP1b), a small protein that regulates calcium, declines with aging in the hippocampus, a brain region important for memory. Here we used gene therapy approaches and found that raising FKBP1b reversed calcium dysregulation and memory impairment in aging rats, allowing them to perform a memory task as well as young rats. These studies identify a potential molecular mechanism of brain aging and may also have implications for treatment of Alzheimer's disease.
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22
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Park CS, Valomon A, Welzl H. Integrative Transcriptome Profiling of Cognitive Aging and Its Preservation through Ser/Thr Protein Phosphatase Regulation. PLoS One 2015; 10:e0130891. [PMID: 26102285 PMCID: PMC4478024 DOI: 10.1371/journal.pone.0130891] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 05/26/2015] [Indexed: 01/28/2023] Open
Abstract
Environmental enrichment has been reported to delay or restore age-related cognitive deficits, however, a mechanism to account for the cause and progression of normal cognitive decline and its preservation by environmental enrichment is lacking. Using genome-wide SAGE-Seq, we provide a global assessment of differentially expressed genes altered with age and environmental enrichment in the hippocampus. Qualitative and quantitative proteomics in naïve young and aged mice was used to further identify phosphorylated proteins differentially expressed with age. We found that increased expression of endogenous protein phosphatase-1 inhibitors in aged mice may be characteristic of long-term environmental enrichment and improved cognitive status. As such, hippocampus-dependent performances in spatial, recognition, and associative memories, which are sensitive to aging, were preserved by environmental enrichment and accompanied by decreased protein phosphatase activity. Age-associated phosphorylated proteins were also found to correspond to the functional categories of age-associated genes identified through transcriptome analysis. Together, this study provides a comprehensive map of the transcriptome and proteome in the aging brain, and elucidates endogenous protein phosphatase-1 inhibition as a potential means through which environmental enrichment may ameliorate age-related cognitive deficits.
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Affiliation(s)
- C. Sehwan Park
- Brain Research Institute, Medical Faculty of the University of Zürich and Department of Health Science and Technology ETH Zürich, Zürich, Switzerland
| | - Amandine Valomon
- Brain Research Institute, Medical Faculty of the University of Zürich and Department of Health Science and Technology ETH Zürich, Zürich, Switzerland
- Institute of Pharmacology and Toxicology, Human Sleep Psychopharmacology, University of Zürich, Zürich, Switzerland
| | - Hans Welzl
- Institute of Anatomy, Neuroanatomy and Behavior, University of Zürich, Zürich, Switzerland
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23
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Scutt G, Allen M, Kemenes G, Yeoman M. A switch in the mode of the sodium/calcium exchanger underlies an age-related increase in the slow afterhyperpolarization. Neurobiol Aging 2015; 36:2838-49. [PMID: 26163984 DOI: 10.1016/j.neurobiolaging.2015.06.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 06/08/2015] [Accepted: 06/08/2015] [Indexed: 12/19/2022]
Abstract
During aging, the Ca(2+)-sensitive slow afterhyperpolarization (sAHP) of hippocampal neurons is known to increase in duration. This change has also been observed in the serotonergic cerebral giant cells (CGCs) of the pond snail Lymnaea stagnalis, but has yet to be characterized. In this article, we confirm that there is a reduction in firing rate, an increase in the duration of the sAHP, and an alteration in the strength and speed of spike frequency adaptation in the CGCs during aging, a finding that is compatible with an increase in the sAHP current. We go on to show that age-related changes in the kinetics of spike frequency adaptation are consistent with a reduction in Ca(2+) clearance from the cell, which we confirm with Ca(2+) imaging and pharmacological manipulation of the sodium calcium exchanger. These experiments suggest that the sodium calcium exchanger may be switching to a reverse-mode configuration in the CGCs during aging.
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Affiliation(s)
- Greg Scutt
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK.
| | - Marcus Allen
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK
| | - György Kemenes
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, Brighton, UK
| | - Mark Yeoman
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK
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Martin-Cano FE, Camello-Almaraz C, Macías JG, Pozo MJ, Camello PJ. Propagation of Intracellular Ca2+ Signals in Aged Exocrine Cells. J Gerontol A Biol Sci Med Sci 2015; 71:145-52. [PMID: 25805851 DOI: 10.1093/gerona/glv018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 02/03/2015] [Indexed: 02/03/2023] Open
Abstract
There is little information on the effects of aging in the propagation of calcium signals and its underlying mechanisms. We studied the effects of aging on propagation of Ca(2+) signals in pancreatic acinar cells. Fura-2 loaded cells isolated from young (3-4 months old) and aged (24 months old) mouse responded to acetylcholine (ACh) and cholecystokinin (CCK) with a polarized Ca(2+) response initiated at the secretory pole before spreading to the basal one. Aging slowed down the propagation of the response to ACh but enhanced the velocity of the CCK response. This pattern can be explained by the age-induced depolarization of mitochondria, because it can be reproduced in young cells by mitochondrial inhibitors. Aging also increased the role of acidic stores in the CCK signal, as judged by the folimycin-induced suppression of the polarization in aged but not in young cells. The involvement of ryanodine receptors in the ACh response was also enhanced, as indicated by the loss of polarization after the treatment with 8Br-cyclic ADP ribose. Therefore, we conclude that aging modifies differentially the propagation of ACh and CCK-evoked Ca(2+) signals through mitochondrial depolarization and changes in the role of the acidic Ca(2+) stores and ryanodine receptors in the initiation of the signals.
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Affiliation(s)
- Francisco E Martin-Cano
- Department of Physiology, Faculty of Nursing and Occupational Therapy, University of Extremadura, Cáceres, Spain
| | - Cristina Camello-Almaraz
- Department of Physiology, Faculty of Nursing and Occupational Therapy, University of Extremadura, Cáceres, Spain
| | | | - Maria J Pozo
- Department of Physiology, Faculty of Nursing and Occupational Therapy, University of Extremadura, Cáceres, Spain
| | - Pedro J Camello
- Department of Physiology, Faculty of Nursing and Occupational Therapy, University of Extremadura, Cáceres, Spain.
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Paula-Lima AC, Adasme T, Hidalgo C. Contribution of Ca2+ release channels to hippocampal synaptic plasticity and spatial memory: potential redox modulation. Antioxid Redox Signal 2014; 21:892-914. [PMID: 24410659 DOI: 10.1089/ars.2013.5796] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
SIGNIFICANCE Memory is an essential human cognitive function. Consequently, to unravel the cellular and molecular mechanisms responsible for the synaptic plasticity events underlying memory formation, storage and loss represents a major challenge of present-day neuroscience. RECENT ADVANCES This review article first describes the wide-ranging functions played by intracellular Ca2+ signals in the activity-dependent synaptic plasticity processes underlying hippocampal spatial memory, and next, it focuses on how the endoplasmic reticulum Ca2+ release channels, the ryanodine receptors, and the inositol 1,4,5-trisphosphate receptors contribute to these processes. We present a detailed examination of recent evidence supporting the key role played by Ca2+ release channels in synaptic plasticity, including structural plasticity, and the formation/consolidation of spatial memory in the hippocampus. CRITICAL ISSUES Changes in cellular oxidative state particularly affect the function of Ca2+ release channels and alter hippocampal synaptic plasticity and the associated memory processes. Emphasis is placed in this review on how defective Ca2+ release, presumably due to increased levels of reactive oxygen species, may cause the hippocampal functional defects that are associated to aging and Alzheimer's disease (AD). FUTURE DIRECTIONS Additional studies should examine the precise molecular mechanisms by which Ca2+ release channels contribute to hippocampal synaptic plasticity and spatial memory formation/consolidation. Future studies should test whether redox-modified Ca2+ release channels contribute toward generating the intracellular Ca2+ signals required for sustained synaptic plasticity and hippocampal spatial memory, and whether loss of redox balance and oxidative stress, by altering Ca2+ release channel function, presumably contribute to the abnormal memory processes that occur during aging and AD.
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Affiliation(s)
- Andrea C Paula-Lima
- 1 Faculty of Dentistry, Institute for Research in Dental Sciences, Universidad de Chile , Santiago, Chile
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26
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Del Prete D, Checler F, Chami M. Ryanodine receptors: physiological function and deregulation in Alzheimer disease. Mol Neurodegener 2014; 9:21. [PMID: 24902695 PMCID: PMC4063224 DOI: 10.1186/1750-1326-9-21] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 05/18/2014] [Indexed: 12/21/2022] Open
Abstract
Perturbed Endoplasmic Reticulum (ER) calcium (Ca2+) homeostasis emerges as a central player in Alzheimer disease (AD). Accordingly, different studies have reported alterations of the expression and the function of Ryanodine Receptors (RyR) in human AD-affected brains, in cells expressing familial AD-linked mutations on the β amyloid precursor protein (βAPP) and presenilins (the catalytic core in γ-secretase complexes cleaving the βAPP, thereby generating amyloid β (Aβ) peptides), as well as in the brain of various transgenic AD mice models. Data converge to suggest that RyR expression and function alteration are associated to AD pathogenesis through the control of: i) βAPP processing and Aβ peptide production, ii) neuronal death; iii) synaptic function; and iv) memory and learning abilities. In this review, we document the network of evidences suggesting that RyR could play a complex dual "compensatory/protective versus pathogenic" role contributing to the setting of histopathological lesions and synaptic deficits that are associated with the disease stages. We also discuss the possible mechanisms underlying RyR expression and function alterations in AD. Finally, we review recent publications showing that drug-targeting blockade of RyR and genetic manipulation of RyR reduces Aβ production, stabilizes synaptic transmission, and prevents learning and memory deficits in various AD mouse models. Chemically-designed RyR "modulators" could therefore be envisioned as new therapeutic compounds able to delay or block the progression of AD.
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Affiliation(s)
| | - Frédéric Checler
- Université de Nice Sophia Antipolis, IPMC, Sophia Antipolis, Nice, F-06560 Valbonne, France.
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27
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Gant JC, Blalock EM, Chen KC, Kadish I, Porter NM, Norris CM, Thibault O, Landfield PW. FK506-binding protein 1b/12.6: a key to aging-related hippocampal Ca2+ dysregulation? Eur J Pharmacol 2013; 739:74-82. [PMID: 24291098 DOI: 10.1016/j.ejphar.2013.10.070] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 10/16/2013] [Accepted: 10/17/2013] [Indexed: 12/25/2022]
Abstract
It has been recognized for some time that the Ca(2+)-dependent slow afterhyperpolarization (sAHP) is larger in hippocampal neurons of aged compared with young animals. In addition, extensive studies since have shown that other Ca(2+)-mediated electrophysiological responses are increased in hippocampus with aging, including Ca(2+) transients, L-type voltage-gated Ca(2+) channel activity, Ca(2+) spike duration and action potential accommodation. Elevated Ca(2+)-induced Ca(2+) release from ryanodine receptors (RyRs) appears to drive amplification of the Ca(2+) responses. Components of this Ca(2+) dysregulation phenotype correlate with deficits in cognitive function and plasticity, indicating they may play critical roles in aging-related impairment of brain function. However, the molecular mechanisms underlying aging-related Ca(2+) dysregulation are not well understood. FK506-binding proteins 1a and 1b (FKBP1a/1b, also known as FKBP12/12.6) are immunophilin proteins that bind the immunosuppressant drugs FK506 and rapamycin. In muscle cells, FKBP1a/1b also bind RyRs and inhibits Ca(2+)-induced Ca(2+) release, but it is not clear whether FKBPs act similarly in brain cells. Recently, we found that selectively disrupting hippocampal FKBP1b function in young rats, either by microinjecting adeno-associated viral vectors expressing siRNA, or by treatment with rapamycin, increases the sAHP and recapitulates much of the hippocampal Ca(2+) dysregulation phenotype. Moreover, in microarray studies, we found FKBP1b gene expression was downregulated in hippocampus of aging rats and early-stage Alzheimer's disease subjects. These results suggest the novel hypothesis that declining FKBP function is a key factor in aging-related Ca(2+) dysregulation in the brain and point to potential new therapeutic targets for counteracting unhealthy brain aging.
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Affiliation(s)
- J C Gant
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, 800 Rose St., UKMC Lexington, KY 40536, United States
| | - E M Blalock
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, 800 Rose St., UKMC Lexington, KY 40536, United States
| | - K-C Chen
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, 800 Rose St., UKMC Lexington, KY 40536, United States
| | - I Kadish
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, 800 Rose St., UKMC Lexington, KY 40536, United States
| | - N M Porter
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, 800 Rose St., UKMC Lexington, KY 40536, United States
| | - C M Norris
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, 800 Rose St., UKMC Lexington, KY 40536, United States
| | - O Thibault
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, 800 Rose St., UKMC Lexington, KY 40536, United States
| | - P W Landfield
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, 800 Rose St., UKMC Lexington, KY 40536, United States.
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Schmunk G, Gargus JJ. Channelopathy pathogenesis in autism spectrum disorders. Front Genet 2013; 4:222. [PMID: 24204377 PMCID: PMC3817418 DOI: 10.3389/fgene.2013.00222] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Accepted: 10/09/2013] [Indexed: 01/12/2023] Open
Abstract
Autism spectrum disorder (ASD) is a syndrome that affects normal brain development and is characterized by impaired social interaction as well as verbal and non-verbal communication and by repetitive, stereotypic behavior. ASD is a complex disorder arising from a combination of multiple genetic and environmental factors that are independent from racial, ethnic and socioeconomical status. The high heritability of ASD suggests a strong genetic basis for the disorder. Furthermore, a mounting body of evidence implies a role of various ion channel gene defects (channelopathies) in the pathogenesis of autism. Indeed, recent genome-wide association, and whole exome- and whole-genome resequencing studies linked polymorphisms and rare variants in calcium, sodium and potassium channels and their subunits with susceptibility to ASD, much as they do with bipolar disorder, schizophrenia and other neuropsychiatric disorders. Moreover, animal models with these genetic variations recapitulate endophenotypes considered to be correlates of autistic behavior seen in patients. An ion flux across the membrane regulates a variety of cell functions, from generation of action potentials to gene expression and cell morphology, thus it is not surprising that channelopathies have profound effects on brain functions. In the present work, we summarize existing evidence for the role of ion channel gene defects in the pathogenesis of autism with a focus on calcium signaling and its downstream effects.
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Affiliation(s)
- Galina Schmunk
- Department of Physiology and Biophysics, University of California Irvine, CA, USA ; UCI Center for Autism Research and Treatment, School of Medicine, University of California Irvine, CA, USA
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29
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Cataldi M. The changing landscape of voltage-gated calcium channels in neurovascular disorders and in neurodegenerative diseases. Curr Neuropharmacol 2013; 11:276-97. [PMID: 24179464 PMCID: PMC3648780 DOI: 10.2174/1570159x11311030004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 02/02/2013] [Accepted: 02/14/2013] [Indexed: 12/12/2022] Open
Abstract
It is a common belief that voltage-gated calcium channels (VGCC) cannot carry toxic amounts of Ca2+ in neurons. Also, some of them as L-type channels are essential for Ca2+-dependent regulation of prosurvival gene-programs. However, a wealth of data show a beneficial effect of drugs acting on VGCCs in several neurodegenerative and neurovascular diseases. In the present review, we explore several mechanisms by which the “harmless” VGCCs may become “toxic” for neurons. These mechanisms could explain how, though usually required for neuronal survival, VGCCs may take part in neurodegeneration. We will present evidence showing that VGCCs can carry toxic Ca2+ when: a) their density or activity increases because of aging, chronic hypoxia or exposure to β-amyloid peptides or b) Ca2+-dependent action potentials carry high Ca2+ loads in pacemaker neurons. Besides, we will examine conditions in which VGCCs promote neuronal cell death without carrying excess Ca2+. This can happen, for instance, when they carry metal ions into the neuronal cytoplasm or when a pathological decrease in their activity weakens Ca2+-dependent prosurvival gene programs. Finally, we will explore the role of VGCCs in the control of nonneuronal cells that take part to neurodegeneration like those of the neurovascular unit or of microglia.
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Affiliation(s)
- Mauro Cataldi
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, Federico II University of Naples, Italy
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30
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Martín-Cano FE, Camello-Almaraz C, Hernandez D, Pozo MJ, Camello PJ. mTOR pathway and Ca²⁺ stores mobilization in aged smooth muscle cells. Aging (Albany NY) 2013; 5:339-46. [PMID: 23661091 PMCID: PMC3701109 DOI: 10.18632/aging.100555] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Aging is considered to be driven by the so called senescence pathways, especially the mTOR route, although there is almost no information on its activity in aged tissues. Aging also induces Ca2+ signal alterations, but information regarding the mechanisms for these changes is almost inexistent. We investigated the possible involvement of the mTOR pathway in the age-dependent changes on Ca2+ stores mobilization in colonic smooth muscle cells of young (4 month old) and aged (24 month old) guinea pigs. mTORC1 activity was enhanced in aged smooth muscle, as revealed by phosphorylation of mTOR and its direct substrates S6K1 and 4E-BP1. Mobilization of intracellular Ca2+ stores through IP3R or RyR channels was impaired in aged cells, and it was facilitated by mTOR and by FKBP12, as indicated by the inhibitory effects of KU0063794 (a direct mTOR inhibitor), rapamycin (a FKBP12-mediated mTOR inhibitor) and FK506 (an FKBP12 binding immunosuppressant). Aging suppressed the facilitation of the Ca2+ mobilization by FKBP12 but not by mTOR, without changing the total expression of FKBP12 protein. In conclusion, or study shows that in smooth muscle aging enhances the constitutive activity of mTORC1 pathway and impairs Ca2+ stores mobilization by suppression of the FKBP12-induced facilitation of Ca2+ release.
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Affiliation(s)
- Francisco E Martín-Cano
- Department of Physiology, Faculty of Nursing and Faculty of Veterinary Sciences, University of Extremadura, 10003 Cáceres, Spain
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31
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Thibault O, Anderson KL, DeMoll C, Brewer LD, Landfield PW, Porter NM. Hippocampal calcium dysregulation at the nexus of diabetes and brain aging. Eur J Pharmacol 2013; 719:34-43. [PMID: 23872402 DOI: 10.1016/j.ejphar.2013.07.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 07/11/2013] [Indexed: 01/19/2023]
Abstract
Recently it has become clear that conditions of insulin resistance/metabolic syndrome, obesity and diabetes, are linked with moderate cognitive impairment in normal aging and elevated risk of Alzheimer's disease. It appears that a common feature of these conditions is impaired insulin signaling, affecting the brain as well as peripheral target tissues. A number of studies have documented that insulin directly affects brain processes and that reduced insulin signaling results in impaired learning and memory. Several studies have also shown that diabetes induces Ca(2+) dysregulation in neurons. Because brain aging is associated with substantial Ca(2+) dyshomeostasis, it has been proposed that impaired insulin signaling exacerbates or accelerates aging-related Ca(2+) dyshomeostasis. However, there have been few studies examining insulin interactions with Ca(2+) regulation in aging animals. We have been testing predictions of the Ca(2+) dysregulation/diabetes/brain aging hypothesis and have found that insulin and insulin-sensitizers (thiazolidinediones) target several hippocampal Ca(2+)-related processes affected by aging. The drugs appear able to reduce the age-dependent increase in Ca(2+) transients and the Ca(2+) -sensitive afterhyperpolarization. Thus, while additional testing is needed, the results to date are consistent with the view that strategies that enhance insulin signaling can counteract the effect of aging on Ca(2+) dysregulation.
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Affiliation(s)
- Olivier Thibault
- Department of Molecular and Biomedical Pharmacology, MS 313, 800 Rose Street, University of Kentucky Medical Center, Lexington, KY 40536, United States.
| | - Katie L Anderson
- Department of Molecular and Biomedical Pharmacology, MS 313, 800 Rose Street, University of Kentucky Medical Center, Lexington, KY 40536, United States
| | - Chris DeMoll
- Department of Molecular and Biomedical Pharmacology, MS 313, 800 Rose Street, University of Kentucky Medical Center, Lexington, KY 40536, United States
| | - Lawrence D Brewer
- Department of Molecular and Biomedical Pharmacology, MS 313, 800 Rose Street, University of Kentucky Medical Center, Lexington, KY 40536, United States
| | - Philip W Landfield
- Department of Molecular and Biomedical Pharmacology, MS 313, 800 Rose Street, University of Kentucky Medical Center, Lexington, KY 40536, United States
| | - Nada M Porter
- Department of Molecular and Biomedical Pharmacology, MS 313, 800 Rose Street, University of Kentucky Medical Center, Lexington, KY 40536, United States
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Baker KD, Edwards TM, Rickard NS. The role of intracellular calcium stores in synaptic plasticity and memory consolidation. Neurosci Biobehav Rev 2013; 37:1211-39. [PMID: 23639769 DOI: 10.1016/j.neubiorev.2013.04.011] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 04/18/2013] [Accepted: 04/22/2013] [Indexed: 12/20/2022]
Abstract
Memory processing requires tightly controlled signalling cascades, many of which are dependent upon intracellular calcium (Ca(2+)). Despite this, most work investigating calcium signalling in memory formation has focused on plasma membrane channels and extracellular sources of Ca(2+). The intracellular Ca(2+) release channels, ryanodine receptors (RyRs) and inositol (1,4,5)-trisphosphate receptors (IP3Rs) have a significant capacity to regulate intracellular Ca(2+) signalling. Evidence at both cellular and behavioural levels implicates both RyRs and IP3Rs in synaptic plasticity and memory formation. Pharmacobehavioural experiments using young chicks trained on a single-trial discrimination avoidance task have been particularly useful by demonstrating that RyRs and IP3Rs have distinct roles in memory formation. RyR-dependent Ca(2+) release appears to aid the consolidation of labile memory into a persistent long-term memory trace. In contrast, IP3Rs are required during long-term memory. This review discusses various functions for RyRs and IP3Rs in memory processing, including neuro- and glio-transmitter release, dendritic spine remodelling, facilitating vasodilation, and the regulation of gene transcription and dendritic excitability. Altered Ca(2+) release from intracellular stores also has significant implications for neurodegenerative conditions.
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Affiliation(s)
- Kathryn D Baker
- School of Psychology and Psychiatry, Monash University, Clayton 3800, Victoria, Australia.
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Direct association of the reticulon protein RTN1A with the ryanodine receptor 2 in neurons. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1421-33. [PMID: 23454728 PMCID: PMC3636420 DOI: 10.1016/j.bbamcr.2013.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 02/11/2013] [Accepted: 02/14/2013] [Indexed: 11/21/2022]
Abstract
RTN1A is a reticulon protein with predominant localization in the endoplasmic reticulum (ER). It was previously shown that RTN1A is expressed in neurons of the mammalian central nervous system but functional information remains sparse. To elucidate the neuronal function of RTN1A, we chose to focus our investigation on identifying possible novel binding partners specifically interacting with the unique N-terminus of RTN1A. Using a nonbiased approach involving GST pull-downs and MS analysis, we identified the intracellular calcium release channel ryanodine receptor 2 (RyR2) as a direct binding partner of RTN1A. The RyR2 binding site was localized to a highly conserved 150-amino acid residue region. RTN1A displays high preference for RyR2 binding in vitro and in vivo and both proteins colocalize in hippocampal neurons and Purkinje cells. Moreover, we demonstrate the precise subcellular localization of RTN1A in Purkinje cells and show that RTN1A inhibits RyR channels in [(3)H]ryanodine binding studies on brain synaptosomes. In a functional assay, RTN1A significantly reduced RyR2-mediated Ca(2+) oscillations. Thus, RTN1A and RyR2 might act as functional partners in the regulation of cytosolic Ca(2+) dynamics the in neurons.
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34
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Briggs CA, Schneider C, Richardson JC, Stutzmann GE. β amyloid peptide plaques fail to alter evoked neuronal calcium signals in APP/PS1 Alzheimer's disease mice. Neurobiol Aging 2013; 34:1632-43. [PMID: 23337342 DOI: 10.1016/j.neurobiolaging.2012.12.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 12/04/2012] [Accepted: 12/18/2012] [Indexed: 12/30/2022]
Abstract
Alzheimer's disease (AD) is a multifactorial disorder of unknown etiology. Mechanistically, beta amyloid peptides (Aβ) and elevated Ca(2+) have been implicated as proximal and likely interactive features of the disease process. We tested the hypothesis that proximity to Aβ plaque might exacerbate activity-dependent neuronal Ca(2+) signaling in hippocampal pyramidal neurons from APPSWE/PS1M146V mice. Using combined approaches of whole cell patch clamp recording and 2-photon imaging of neuronal Ca(2+) signals with thioflavin-S plaque labeling in hippocampal slices, we found no correlation between thioflavin-S labeled Aβ plaque proximity and Ca(2+) responses triggered by ryanodine receptor (RyR) activation or action potentials in either dendrites or somata of AD mice, regardless of age. Baseline and RyR-stimulated spontaneous excitatory postsynaptic potentials also showed little difference in relation to Aβ plaque proximity. Consistent with previous studies, RyR-evoked Ca(2+) release in APPSWE/PS1M146V mice was greater than in nontransgenic controls. Within the soma, RyR-evoked Ca(2+) release was elevated in older APPSWE/PS1M146V mice compared with younger APPSWE/PS1M146V mice, but was still independent of plaque proximity. The results indicate that early Ca(2+) signaling disruptions can become yet more severe with age through mechanisms independent of Aβ plaques, suggesting that alternative pathogenic mechanisms might contribute to AD-associated dysfunction.
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Affiliation(s)
- Clark A Briggs
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
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35
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FK506 binding proteins: Cellular regulators of intracellular Ca2+ signalling. Eur J Pharmacol 2013; 700:181-93. [DOI: 10.1016/j.ejphar.2012.12.029] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 12/04/2012] [Accepted: 12/18/2012] [Indexed: 02/04/2023]
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36
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Ryanodine receptor blockade reduces amyloid-β load and memory impairments in Tg2576 mouse model of Alzheimer disease. J Neurosci 2012; 32:11820-34. [PMID: 22915123 DOI: 10.1523/jneurosci.0875-12.2012] [Citation(s) in RCA: 184] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In Alzheimer disease (AD), the perturbation of the endoplasmic reticulum (ER) calcium (Ca²⁺) homeostasis has been linked to presenilins, the catalytic core in γ-secretase complexes cleaving the amyloid precursor protein (APP), thereby generating amyloid-β (Aβ) peptides. Here we investigate whether APP contributes to ER Ca²⁺ homeostasis and whether ER Ca²⁺ could in turn influence Aβ production. We show that overexpression of wild-type human APP (APP(695)), or APP harboring the Swedish double mutation (APP(swe)) triggers increased ryanodine receptor (RyR) expression and enhances RyR-mediated ER Ca²⁺ release in SH-SY5Y neuroblastoma cells and in APP(swe)-expressing (Tg2576) mice. Interestingly, dantrolene-induced lowering of RyR-mediated Ca²⁺ release leads to the reduction of both intracellular and extracellular Aβ load in neuroblastoma cells as well as in primary cultured neurons derived from Tg2576 mice. This Aβ reduction can be accounted for by decreased Thr-668-dependent APP phosphorylation and β- and γ-secretases activities. Importantly, dantrolene diminishes Aβ load, reduces Aβ-related histological lesions, and slows down learning and memory deficits in Tg2576 mice. Overall, our data document a key role of RyR in Aβ production and learning and memory performances, and delineate RyR-mediated control of Ca²⁺ homeostasis as a physiological paradigm that could be targeted for innovative therapeutic approaches.
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37
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Ye L, Varamini B, Lamming DW, Sabatini DM, Baur JA. Rapamycin has a biphasic effect on insulin sensitivity in C2C12 myotubes due to sequential disruption of mTORC1 and mTORC2. Front Genet 2012; 3:177. [PMID: 22973301 PMCID: PMC3438685 DOI: 10.3389/fgene.2012.00177] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 08/23/2012] [Indexed: 12/11/2022] Open
Abstract
Rapamycin, an inhibitor of mTOR complex 1 (mTORC1), improves insulin sensitivity in acute studies in vitro and in vivo by disrupting a negative feedback loop mediated by S6 kinase. We find that rapamycin has a clear biphasic effect on insulin sensitivity in C2C12 myotubes, with enhanced responsiveness during the first hour that declines to almost complete insulin resistance by 24-48 h. We and others have recently observed that chronic rapamycin treatment induces insulin resistance in rodents, at least in part due to disruption of mTORC2, an mTOR-containing complex that is not acutely sensitive to the drug. Chronic rapamycin treatment may also impair insulin action via the inhibition of mTORC1-dependent mitochondrial biogenesis and activity, which could result in a buildup of lipid intermediates that are known to trigger insulin resistance. We confirmed that rapamycin inhibits expression of PGC-1α, a key mitochondrial transcription factor, and acutely reduces respiration rate in myotubes. However, rapamycin did not stimulate phosphorylation of PKCθ, a central mediator of lipid-induced insulin resistance. Instead, we found dramatic disruption of mTORC2, which coincided with the onset of insulin resistance. Selective inhibition of mTORC1 or mTORC2 by shRNA-mediated knockdown of specific components (Raptor and Rictor, respectively) confirmed that mitochondrial effects of rapamycin are mTORC1-dependent, whereas insulin resistance was recapitulated only by knockdown of mTORC2. Thus, mTORC2 disruption, rather than inhibition of mitochondria, causes insulin resistance in rapamycin-treated myotubes, and this system may serve as a useful model to understand the effects of rapamycin on mTOR signaling in vivo.
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Affiliation(s)
- Lan Ye
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania Philadelphia, PA, USA
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38
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Yamaguchi M. Role of regucalcin in brain calcium signaling: involvement in aging. Integr Biol (Camb) 2012; 4:825-837. [DOI: 10.1039/c2ib20042b] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Affiliation(s)
- Masayoshi Yamaguchi
- Department of Foods and Nutrition, The University of Georgia, 425 River Road, Rhodes Center, Room 448, Athens, GA 30602-2771, USA
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39
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Takano K, Liu D, Tarpey P, Gallant E, Lam A, Witham S, Alexov E, Chaubey A, Stevenson RE, Schwartz CE, Board PG, Dulhunty AF. An X-linked channelopathy with cardiomegaly due to a CLIC2 mutation enhancing ryanodine receptor channel activity. Hum Mol Genet 2012; 21:4497-507. [PMID: 22814392 DOI: 10.1093/hmg/dds292] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Chloride intracellular channel 2 (CLIC2) protein is a member of the glutathione transferase class of proteins. Its' only known function is the regulation of ryanodine receptor (RyR) intracellular Ca(2+) release channels. These RyR proteins play a major role in the regulation of Ca(2+) signaling in many cells. Utilizing exome capture and deep sequencing of genes on the X-chromosome, we have identified a mutation in CLIC2 (c.303C>G, p.H101Q) which is associated with X-linked intellectual disability (ID), atrial fibrillation, cardiomegaly, congestive heart failure (CHF), some somatic features and seizures. Functional studies of the H101Q variant indicated that it stimulated rather than inhibited the action of RyR channels, with channels remaining open for longer times and potentially amplifying Ca(2+) signals dependent on RyR channel activity. The overly active RyRs in cardiac and skeletal muscle cells and neuronal cells would result in abnormal cardiac function and trigger post-synaptic pathways and neurotransmitter release. The presence of both cardiomegaly and CHF in the two affected males and atrial fibrillation in one are consistent with abnormal RyR2 channel function. Since the dysfunction of RyR2 channels in the brain via 'leaky mutations' can result in mild developmental delay and seizures, our data also suggest a vital role for the CLIC2 protein in maintaining normal cognitive function via its interaction with RyRs in the brain. Therefore, our patients appear to suffer from a new channelopathy comprised of ID, seizures and cardiac problems because of enhanced Ca(2+) release through RyRs in neuronal cells and cardiac muscle cells.
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Affiliation(s)
- Kyoko Takano
- JC Self Research Institute, Greenwood Genetic Center, Greenwood, SC 29646, USA
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40
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Sama DM, Mohmmad Abdul H, Furman JL, Artiushin IA, Szymkowski DE, Scheff SW, Norris CM. Inhibition of soluble tumor necrosis factor ameliorates synaptic alterations and Ca2+ dysregulation in aged rats. PLoS One 2012; 7:e38170. [PMID: 22666474 PMCID: PMC3362564 DOI: 10.1371/journal.pone.0038170] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 05/01/2012] [Indexed: 12/14/2022] Open
Abstract
The role of tumor necrosis factor α (TNF) in neural function has been investigated extensively in several neurodegenerative conditions, but rarely in brain aging, where cognitive and physiologic changes are milder and more variable. Here, we show that protein levels for TNF receptor 1 (TNFR1) are significantly elevated in the hippocampus relative to TNF receptor 2 (TNFR2) in aged (22 months) but not young adult (6 months) Fischer 344 rats. To determine if altered TNF/TNFR1 interactions contribute to key brain aging biomarkers, aged rats received chronic (4–6 week) intracranial infusions of XPro1595: a soluble dominant negative TNF that preferentially inhibits TNFR1 signaling. Aged rats treated with XPro1595 showed improved Morris Water Maze performance, reduced microglial activation, reduced susceptibility to hippocampal long-term depression, increased protein levels for the GluR1 type glutamate receptor, and lower L-type voltage sensitive Ca2+ channel (VSCC) activity in hippocampal CA1 neurons. The results suggest that diverse functional changes associated with brain aging may arise, in part, from selective alterations in TNF signaling.
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Affiliation(s)
- Diana M. Sama
- Graduate Center for Gerontology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Hafiz Mohmmad Abdul
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
| | - Jennifer L. Furman
- Molecular & Biomedical Pharmacology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Irina A. Artiushin
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
| | | | - Stephen W. Scheff
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
- Anatomy and Neurobiology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Christopher M. Norris
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
- Molecular & Biomedical Pharmacology, University of Kentucky, Lexington, Kentucky, United States of America
- * E-mail:
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41
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Yeoman M, Scutt G, Faragher R. Insights into CNS ageing from animal models of senescence. Nat Rev Neurosci 2012; 13:435-45. [PMID: 22595787 DOI: 10.1038/nrn3230] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
In recent years, novel model systems have made significant contributions to our understanding of the processes that control the ageing of whole organisms. However, there are limited data to show that the mechanisms that gerontologists have identified as having a role in organismal ageing contribute significantly to the ageing of the central nervous system. Two recent discoveries illustrate this particularly well. The first is the consistent failure of researchers to demonstrate a simple relationship between organismal ageing and oxidative stress--a mechanism often assumed to have a primary role in brain ageing. The second is the demonstration that senescent cells play a causal part in organismal ageing but remain essentially unstudied in a CNS context. We argue that the animal models now available (including rodents, flies, molluscs and worms), if properly applied, will allow a paradigm shift in our current understanding of the normal processes of brain ageing.
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Affiliation(s)
- Mark Yeoman
- School of Pharmacy and Biomolecular Sciences, Huxley Building, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
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42
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Thibault O, Pancani T, Landfield PW, Norris CM. Reduction in neuronal L-type calcium channel activity in a double knock-in mouse model of Alzheimer's disease. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1822:546-9. [PMID: 22265986 PMCID: PMC3293940 DOI: 10.1016/j.bbadis.2012.01.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 12/20/2011] [Accepted: 01/04/2012] [Indexed: 11/25/2022]
Abstract
Increased function of neuronal L-type voltage-sensitive Ca(2+) channels (L-VSCCs) is strongly linked to impaired memory and altered hippocampal synaptic plasticity in aged rats. However, no studies have directly assessed L-VSCC function in any of the common mouse models of Alzheimer's disease where neurologic deficits are typically more robust. Here, we used cell-attached patch-clamp recording techniques to measure L-VSCC activity in CA1 pyramidal neurons of partially dissociated hippocampal "zipper" slices prepared from 14-month-old wild-type mice and memory-impaired APP/PS1 double knock-in mice. Surprisingly, the functional channel density of L-VSCCs was significantly reduced in the APP/PS1 group. No differences in voltage dependency and unitary conductance of L-VSCCs were observed. The results suggest that mechanisms for Ca(2+) dysregulation can differ substantially between animal models of normal aging and models of pathological aging.
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Affiliation(s)
- Olivier Thibault
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington, KY 40536 USA
| | - Tristano Pancani
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington, KY 40536 USA
| | - Philip W. Landfield
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington, KY 40536 USA
| | - Christopher M. Norris
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington, KY 40536 USA
- Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY 40536 USA
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Blalock EM, Buechel HM, Popovic J, Geddes JW, Landfield PW. Microarray analyses of laser-captured hippocampus reveal distinct gray and white matter signatures associated with incipient Alzheimer's disease. J Chem Neuroanat 2011; 42:118-26. [PMID: 21756998 DOI: 10.1016/j.jchemneu.2011.06.007] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2011] [Revised: 06/27/2011] [Accepted: 06/27/2011] [Indexed: 01/03/2023]
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disorder that threatens to reach epidemic proportions as our population ages. Although much research has examined molecular pathways associated with AD, relatively few such studies have focused on the disease's critical early stages. In a prior microarray study we correlated gene expression in hippocampus with degree of Alzheimer's disease and found close associations between upregulation of apparent glial transcription factor/epigenetic/tumor suppressor genes and incipient AD. The results suggested a new model in which AD pathology spreads along myelinated axons (Blalock et al., 2004). However, the microarray analyses were performed on RNA extracted from frozen hand-dissected hippocampal CA1 tissue blocks containing both gray and white matter, limiting the confidence with which transcriptional changes in gray matter could be distinguished from those in white matter. Here, we used laser capture microdissection (LCM) to exclude major white matter tracts while selectively collecting CA1 hippocampal gray matter from formalin-fixed, paraffin-embedded (FFPE) hippocampal sections of the same subjects assessed in our prior study. Microarray analyses of this gray matter-enriched tissue revealed many transcriptional changes similar to those seen in our past study and in studies by others, particularly for downregulated neuron-related genes. Additionally, the present analyses identified several previously undetected pathway alterations, including downregulation of molecules that stabilize ryanodine receptor Ca2+ release and upregulation of vasculature development. Conversely, we found a striking paucity of the upregulated changes in the putative glial and growth-related genes that had been strongly overrepresented in the prior mixed-tissue study. We conclude that FFPE tissue can be a reliable resource for microarray studies of brain tissue, that upregulation of growth-related epigenetic/transcription factors during incipient AD is predominantly localized in and around white matter (supporting our prior findings and model), and that novel alterations in vascular and ryanodine receptor-related pathways in gray matter are closely associated with incipient AD.
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Affiliation(s)
- Eric M Blalock
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington, KY 40536, USA.
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