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Choi C, Kim H, Oh J, Park C, Kim M, Kim CS, Park J. DSCR1 deficiency ameliorates the Aβ pathology of Alzheimer's disease by enhancing microglial activity. Life Sci Alliance 2023; 6:6/2/e202201556. [PMID: 36450444 PMCID: PMC9713304 DOI: 10.26508/lsa.202201556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 12/02/2022] Open
Abstract
Microglial phagocytosis and clearance are important for the removal of amyloid-β (Aβ) plaques in Alzheimer's disease (AD). Chronic exposure of microglia to Aβ plaques leads to microglial metabolic dysfunction, and dysregulation of microglia can accelerate the deposition of Aβ plaques and cause learning and memory impairment. Thus, regulating microglial Aβ clearance is crucial for the development of therapeutics for AD-related dementia. Here, Down syndrome critical region 1 (DSCR1) deficiency ameliorated Aβ plaque deposition in the 5xFAD mouse model of AD by altering microglial activity; however, the Aβ synthesis pathway was not affected. DSCR1 deficiency improved spatial learning and memory impairment in 5xFAD mice. Furthermore, DSCR1-deficient microglia exhibited accelerated lysosomal degradation of Aβ after phagocytosis, and BV2 cells with stable knockdown of DSCR1 demonstrated enhanced lysosomal activity. RNA-sequencing analysis showed that the transcriptional signatures associated with responses to IFN-γ were significantly up-regulated in DSCR1-knockdown BV2 cells treated with Aβ. Our data strongly suggest that DSCR1 is a critical mediator of microglial degradation of amyloid plaques and a new potential microglial therapeutic target in AD.
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Affiliation(s)
- Chiyeol Choi
- Department of Biological Sciences, College of Information and Bioengineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Hyerin Kim
- Department of Biological Sciences, College of Information and Bioengineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Jiyoung Oh
- Department of Biological Sciences, College of Information and Bioengineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Chanho Park
- Department of Biological Sciences, College of Information and Bioengineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Min Kim
- Department of Biological Sciences, College of Information and Bioengineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Chu-Sook Kim
- Department of Biological Sciences, College of Information and Bioengineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Jiyoung Park
- Department of Biological Sciences, College of Information and Bioengineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
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2
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Wong H, Buck JM, Borski C, Pafford JT, Keller BN, Milstead RA, Hanson JL, Stitzel JA, Hoeffer CA. RCAN1 knockout and overexpression recapitulate an ensemble of rest-activity and circadian disruptions characteristic of Down syndrome, Alzheimer's disease, and normative aging. J Neurodev Disord 2022; 14:33. [PMID: 35610565 PMCID: PMC9128232 DOI: 10.1186/s11689-022-09444-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 05/12/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Regulator of calcineurin 1 (RCAN1) is overexpressed in Down syndrome (DS), but RCAN1 levels are also increased in Alzheimer's disease (AD) and normal aging. AD is highly comorbid among individuals with DS and is characterized in part by progressive neurodegeneration that resembles accelerated aging. Importantly, abnormal RCAN1 levels have been demonstrated to promote memory deficits and pathophysiology that appear symptomatic of DS, AD, and aging. Anomalous diurnal rest-activity patterns and circadian rhythm disruptions are also common in DS, AD, and aging and have been implicated in facilitating age-related cognitive decline and AD progression. However, no prior studies have assessed whether RCAN1 dysregulation may also promote the age-associated alteration of rest-activity profiles and circadian rhythms, which could in turn contribute to neurodegeneration in DS, AD, and aging. METHODS The present study examined the impacts of RCAN1 deficiency and overexpression on the photic entrainment, circadian periodicity, intensity and distribution, diurnal patterning, and circadian rhythmicity of wheel running in young (3-6 months old) and aged (9-14 months old) mice of both sexes. RESULTS We found that daily RCAN1 levels in the hippocampus and suprachiasmatic nucleus (SCN) of light-entrained young mice are generally constant and that balanced RCAN1 expression is necessary for normal circadian locomotor activity rhythms. While the light-entrained diurnal period was unaltered, RCAN1-null and RCAN1-overexpressing mice displayed lengthened endogenous (free-running) circadian periods like mouse models of AD and aging. In light-entrained young mice, RCAN1 deficiency and overexpression also recapitulated the general hypoactivity, diurnal rest-wake pattern fragmentation, and attenuated amplitudes of circadian activity rhythms reported in DS, preclinical and clinical AD, healthily aging individuals, and rodent models thereof. Under constant darkness, RCAN1-null and RCAN1-overexpressing mice displayed altered locomotor behavior indicating circadian clock dysfunction. Using the Dp(16)1Yey/+ (Dp16) mouse model for DS, which expresses three copies of Rcan1, we found reduced wheel running activity and rhythmicity in both light-entrained and free-running young Dp16 mice like young RCAN1-overexpressing mice. Critically, these diurnal and circadian deficits were rescued in part or entirely by restoring Rcan1 to two copies in Dp16 mice. We also found that RCAN1 deficiency but not RCAN1 overexpression altered protein levels of the clock gene Bmal1 in the SCN. CONCLUSIONS Collectively, this study's findings suggest that both loss and aberrant gain of RCAN1 precipitate anomalous light-entrained diurnal and circadian activity patterns emblematic of DS, AD, and possibly aging.
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Affiliation(s)
- Helen Wong
- Institute for Behavioral Genetics, University of Colorado Boulder, 1480 30th Street, Boulder, CO, 80309-0447, USA
- Department of Integrative Physiology, University of Colorado, Boulder, CO, 80303, USA
| | - Jordan M Buck
- Institute for Behavioral Genetics, University of Colorado Boulder, 1480 30th Street, Boulder, CO, 80309-0447, USA
- Department of Integrative Physiology, University of Colorado, Boulder, CO, 80303, USA
| | - Curtis Borski
- Institute for Behavioral Genetics, University of Colorado Boulder, 1480 30th Street, Boulder, CO, 80309-0447, USA
- Department of Integrative Physiology, University of Colorado, Boulder, CO, 80303, USA
| | - Jessica T Pafford
- Department of Integrative Physiology, University of Colorado, Boulder, CO, 80303, USA
| | - Bailey N Keller
- Institute for Behavioral Genetics, University of Colorado Boulder, 1480 30th Street, Boulder, CO, 80309-0447, USA
| | - Ryan A Milstead
- Institute for Behavioral Genetics, University of Colorado Boulder, 1480 30th Street, Boulder, CO, 80309-0447, USA
- Department of Integrative Physiology, University of Colorado, Boulder, CO, 80303, USA
| | - Jessica L Hanson
- Institute for Behavioral Genetics, University of Colorado Boulder, 1480 30th Street, Boulder, CO, 80309-0447, USA
- Department of Integrative Physiology, University of Colorado, Boulder, CO, 80303, USA
| | - Jerry A Stitzel
- Institute for Behavioral Genetics, University of Colorado Boulder, 1480 30th Street, Boulder, CO, 80309-0447, USA
- Department of Integrative Physiology, University of Colorado, Boulder, CO, 80303, USA
| | - Charles A Hoeffer
- Institute for Behavioral Genetics, University of Colorado Boulder, 1480 30th Street, Boulder, CO, 80309-0447, USA.
- Department of Integrative Physiology, University of Colorado, Boulder, CO, 80303, USA.
- Linda Crnic Institute, Anschutz Medical Campus, Aurora, CO, 80045, USA.
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Influence of spatial structure on protein damage susceptibility: a bioinformatics approach. Sci Rep 2021; 11:4938. [PMID: 33654113 PMCID: PMC7925522 DOI: 10.1038/s41598-021-84061-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 02/08/2021] [Indexed: 11/08/2022] Open
Abstract
Aging research is a very popular field of research in which the deterioration or decline of various physiological features is studied. Here we consider the molecular level, which can also have effects on the macroscopic level. The proteinogenic amino acids differ in their susceptibilities to non-enzymatic modification. Some of these modifications can lead to protein damage and thus can affect the form and function of proteins. For this, it is important to know the distribution of amino acids between the protein shell/surface and the core. This was investigated in this study for all known structures of peptides and proteins available in the PDB. As a result, it is shown that the shell contains less susceptible amino acids than the core with the exception of thermophilic organisms. Furthermore, proteins could be classified according to their susceptibility. This can then be used in applications such as phylogeny, aging research, molecular medicine, and synthetic biology.
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Martínez-Cué C, Rueda N. Signalling Pathways Implicated in Alzheimer's Disease Neurodegeneration in Individuals with and without Down Syndrome. Int J Mol Sci 2020; 21:E6906. [PMID: 32962300 PMCID: PMC7555886 DOI: 10.3390/ijms21186906] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 02/07/2023] Open
Abstract
Down syndrome (DS), the most common cause of intellectual disability of genetic origin, is characterized by alterations in central nervous system morphology and function that appear from early prenatal stages. However, by the fourth decade of life, all individuals with DS develop neuropathology identical to that found in sporadic Alzheimer's disease (AD), including the development of amyloid plaques and neurofibrillary tangles due to hyperphosphorylation of tau protein, loss of neurons and synapses, reduced neurogenesis, enhanced oxidative stress, and mitochondrial dysfunction and neuroinflammation. It has been proposed that DS could be a useful model for studying the etiopathology of AD and to search for therapeutic targets. There is increasing evidence that the neuropathological events associated with AD are interrelated and that many of them not only are implicated in the onset of this pathology but are also a consequence of other alterations. Thus, a feedback mechanism exists between them. In this review, we summarize the signalling pathways implicated in each of the main neuropathological aspects of AD in individuals with and without DS as well as the interrelation of these pathways.
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Affiliation(s)
- Carmen Martínez-Cué
- Department of Physiology and Pharmacology, Faculty of Medicine, University of Cantabria, 39011 Santander, Spain;
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Oliva J. Proteasome and Organs Ischemia-Reperfusion Injury. Int J Mol Sci 2017; 19:ijms19010106. [PMID: 29301204 PMCID: PMC5796056 DOI: 10.3390/ijms19010106] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 12/12/2017] [Accepted: 12/27/2017] [Indexed: 12/17/2022] Open
Abstract
The treatment of organ failure on patients requires the transplantation of functional organs, from donors. Over time, the methodology of transplantation was improved by the development of organ preservation solutions. The storage of organs in preservation solutions is followed by the ischemia of the organ, resulting in a shortage of oxygen and nutrients, which damage the tissues. When the organ is ready for the transplantation, the reperfusion of the organ induces an increase of the oxidative stress, endoplasmic reticulum stress, and inflammation which causes tissue damage, resulting in a decrease of the transplantation success. However, the addition of proteasome inhibitor in the preservation solution alleviated the injuries due to the ischemia-reperfusion process. The proteasome is a protein structure involved in the regulation the inflammation and the clearance of damaged proteins. The goal of this review is to summarize the role of the proteasome and pharmacological compounds that regulate the proteasome in protecting the organs from the ischemia-reperfusion injury.
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Affiliation(s)
- Joan Oliva
- Department of Medicine, LA BioMed at Harbor UCLA Medical Center, Torrance, CA 90502, USA.
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Jin H, Wang C, Jin G, Ruan H, Gu D, Wei L, Wang H, Wang N, Arunachalam E, Zhang Y, Deng X, Yang C, Xiong Y, Feng H, Yao M, Fang J, Gu J, Cong W, Qin W. Regulator of Calcineurin 1 Gene Isoform 4, Down-regulated in Hepatocellular Carcinoma, Prevents Proliferation, Migration, and Invasive Activity of Cancer Cells and Metastasis of Orthotopic Tumors by Inhibiting Nuclear Translocation of NFAT1. Gastroenterology 2017; 153:799-811.e33. [PMID: 28583823 DOI: 10.1053/j.gastro.2017.05.045] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 05/27/2017] [Accepted: 05/27/2017] [Indexed: 01/09/2023]
Abstract
BACKGROUND & AIMS Individuals with Down syndrome have a low risk for many solid tumors, prompting the search for tumor suppressor genes on human chromosome 21 (HSA21). We aimed to identify and explore potential mechanisms of tumor suppressors on HSA21 in hepatocellular carcinoma (HCC). METHODS We compared expression of HSA21 genes in 14 pairs of primary HCC and adjacent noncancer liver tissues using the Affymetrix HG-U133 Plus 2.0 array (Affymetrix, Santa Clara, CA). HCC tissues and adjacent normal liver tissues were collected from 108 patients at a hospital in China for real-time polymerase chain reaction and immunohistochemical analyses; expression levels of regulator of calcineurin 1 (RCAN1) isoform 4 (RCAN1.4) were associated with clinical features. We overexpressed RCAN1.4 from lentiviral vectors in MHCC97H and HCCLM3 cells and knocked expression down using small interfering RNAs in SMMC7721 and Huh7 cells. Cells were analyzed in proliferation, migration, and invasion assays. HCC cells that overexpressed RCAN1.4 or with RCAN1.4 knockdown were injected into livers or tail veins of nude mice; tumor growth and numbers of lung metastases were quantified. We performed bisulfite pyrosequencing and methylation-specific polymerase chain reaction analyses to analyze CpG island methylation. We measured phosphatase activity of calcineurin in HCC cells. RESULTS RCAN1.4 mRNA and protein levels were significantly decreased in primary HCC compared with adjacent noncancer liver tissues. Reduced levels of RCAN1.4 mRNA were significantly associated with advanced tumor stages, poor differentiation, larger tumor size, and vascular invasion. Kaplan-Meier survival analysis showed that patients with HCCs with lower levels of RCAN1.4 mRNA had shorter time of overall survival and time to recurrence than patients whose tumors had high levels of RCAN1.4 mRNA. In HCC cell lines, expression of RCAN1.4 significantly reduced proliferation, migration, and invasive activity. HCC cells that overexpressed RCAN1.4 formed smaller xenograft tumors, with fewer metastases and blood vessels, than control HCC cells. In HCC cells, RCAN1.4 inhibited expression of insulin-like growth factor 1 and vascular endothelial growth factor A by reducing calcineurin activity and blocking nuclear translocation of nuclear factor of activated T cells (NFAT1). HCC cells incubated with the calcineurin inhibitor cyclosporin A had decreased nuclear level of NFAT1. HCC cells had hypermethylation of a CpG island in the 5' regulatory region of RCAN1.4, which reduced its expression. CONCLUSIONS RCAN1.4 is down-regulated in HCC tissues, compared with non-tumor liver tissues. RCAN1.4 prevents cell proliferation, migration, and invasion in vitro; overexpressed RCAN1.4 in HCC cells prevents growth, angiogenesis, and metastases of xenograft tumors by inhibiting calcineurin activity and nuclear translocation of NFAT1.
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Affiliation(s)
- Haojie Jin
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Cun Wang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Guangzhi Jin
- Department of Pathology, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China
| | - Haoyu Ruan
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Dishui Gu
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Pathophysiology, School of Basic Medical Sciences, Guangdong Medical University, Dongguan, Guangdong, China
| | - Lin Wei
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hui Wang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ning Wang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Einthavy Arunachalam
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; The School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surry, UK
| | - Yurong Zhang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xuan Deng
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chen Yang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yi Xiong
- State Key Laboratory of Microbial Metabolism and College of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Hugang Feng
- Department of Life Science, Imperial College, London, UK
| | - Ming Yao
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jingyuan Fang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jianren Gu
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wenming Cong
- Department of Pathology, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China.
| | - Wenxin Qin
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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Saarikangas J, Caudron F. Spatial regulation of coalesced protein assemblies: Lessons from yeast to diseases. Prion 2017; 11:162-173. [PMID: 28574744 PMCID: PMC5480387 DOI: 10.1080/19336896.2017.1322239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Organisms rely on correctly folded proteins to carry out essential functions. Protein quality control factors guard proteostasis and prevent protein misfolding. When quality control fails and in response to diverse stresses, many proteins start to accumulate at specific deposit sites that maintain cellular organization and protect the functionality of coalescing proteins. These transitions involve dedicated proteins that promote coalescence and are facilitated by endo-membranes and cytoskeletal platforms. Moreover, several proteins make use of weak multivalent interactions or conformational templating to drive the formation of large-scale assemblies. Formation of such assemblies is often associated with a change in biochemical activity that can be used by cells to execute biochemical decisions in a localized manner during development and adaption. Since all assembly types impact cell physiology, their localization and dynamics need to be tightly regulated. Interestingly, at least some of the regulatory mechanisms are shared by functional membrane-less organelles and assemblies of terminally aggregated proteins. Furthermore, constituents of functional assemblies can aggregate and become non-functional during aging. Here we present the current knowledge as to how coalescing protein assemblies are spatially organized in cells and we postulate that failures in their spatial confinement might underscore certain aspects of aging and neurodegenerative diseases.
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Affiliation(s)
- Juha Saarikangas
- a ETH Zurich, Institute of Biochemistry , Zurich , Switzerland.,b Wissenschaftskolleg zu Berlin , Institute for Advanced Study , Berlin , Germany.,c Helsinki Institute of Life Science, University of Helsinki , Helsinki , Finland.,d Faculty of Biological and Environmental Sciences , University of Helsinki , Helsinki , Finland
| | - Fabrice Caudron
- e Randall Division of Cell and Molecular Biophysics , King's College London , London , UK
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Wong H, Levenga J, Cain P, Rothermel B, Klann E, Hoeffer C. RCAN1 overexpression promotes age-dependent mitochondrial dysregulation related to neurodegeneration in Alzheimer's disease. Acta Neuropathol 2015; 130:829-43. [PMID: 26497675 DOI: 10.1007/s00401-015-1499-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Revised: 10/15/2015] [Accepted: 10/16/2015] [Indexed: 10/22/2022]
Abstract
Aging is the largest risk factor for Alzheimer's disease (AD). Patients with Down syndrome (DS) develop symptoms consistent with early-onset AD, suggesting that overexpression of chromosome 21 genes such as Regulator of Calcineurin 1 (RCAN1) plays a role in AD pathogenesis. RCAN1 levels are increased in the brain of DS and AD patients but also in the human brain with normal aging. RCAN1 has been implicated in several neuronal functions, but whether its increased expression is correlative or causal in the aging-related progression of AD remains elusive. We show that brain-specific overexpression of the human RCAN1.1S isoform in mice promotes early age-dependent memory and synaptic plasticity deficits, tau pathology, and dysregulation of dynamin-related protein 1 (DRP1) activity associated with mitochondrial dysfunction and oxidative stress, reproducing key AD features. Based on these findings, we propose that chronic RCAN1 overexpression during aging alters DRP1-mediated mitochondrial fission and thus acts to promote AD-related progressive neurodegeneration.
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Affiliation(s)
- Helen Wong
- Center for Neural Science, New York University, New York, NY, USA
| | - Josien Levenga
- Department of Integrated of Physiology, Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA
| | - Peter Cain
- Department of Integrated of Physiology, Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA
| | - Beverly Rothermel
- Department of Cardiology, University of Texas-Southwestern, Dallas, TX, USA
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY, USA
| | - Charles Hoeffer
- Department of Integrated of Physiology, Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA.
- New York University School of Medicine, New York, NY, USA.
- Linda Crnic Institute, Denver, CO, USA.
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Wu Y, Deng Y, Zhang S, Luo Y, Cai F, Zhang Z, Zhou W, Li T, Song W. Amyloid-β precursor protein facilitates the regulator of calcineurin 1-mediated apoptosis by downregulating proteasome subunit α type-5 and proteasome subunit β type-7. Neurobiol Aging 2014; 36:169-77. [PMID: 25194880 DOI: 10.1016/j.neurobiolaging.2014.07.029] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 07/23/2014] [Accepted: 07/23/2014] [Indexed: 11/28/2022]
Abstract
Individuals with Down syndrome (DS), caused by trisomy of chromosome 21, inevitably develop characteristic Alzheimer's disease (AD) neuropathology, including neuritic plaques, neurofibrillary tangles, and neuronal loss. Amyloid-β protein, the major component of neuritic plaques, is the proteolytic product of amyloid-β precursor protein (APP). APP and the regulator of calcineurin 1 (RCAN1) genes on chromosome 21 play a pivotal role in promoting plaque formation and neuronal apoptosis. However, the mechanism underlying AD pathogenesis in DS is not well defined. In this study, we demonstrated that APP significantly increased RCAN1 level in both cells and transgenic mice. Overexpression of APP significantly reduced the expression of 2 proteasome subunits, proteasome subunit α type-5 and proteasome subunit β type-7, leading to the inhibition of proteasomal degradation of RCAN1. Furthermore, knockdown of RCAN1 expression attenuated APP-induced neuronal apoptosis. Taken together, the results clearly showed that APP has a previously unknown function in regulating RCAN1-mediated neuronal apoptosis through the proteasome pathway. Our study demonstrates a novel mechanism by which overexpression of APP and RCAN1 causes neurodegeneration and AD pathogenesis in DS, and it provides new insights into the potential of targeting APP-induced proteasomal impairment and RCAN1 accumulation for AD and DS treatment.
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Affiliation(s)
- Yili Wu
- Chongqing City Key Lab of Translational Medical Research in Cognitive Development and Learning and Memory Disorders and Ministry of Education Key Lab of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China; Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Yu Deng
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Shuting Zhang
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Yawen Luo
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Fang Cai
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Zhuohua Zhang
- State Key Laboratory of Medical Genetics of China, Central South University, Changsha, Hunan, China
| | - Weihui Zhou
- Chongqing City Key Lab of Translational Medical Research in Cognitive Development and Learning and Memory Disorders and Ministry of Education Key Lab of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Tingyu Li
- Chongqing City Key Lab of Translational Medical Research in Cognitive Development and Learning and Memory Disorders and Ministry of Education Key Lab of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.
| | - Weihong Song
- Chongqing City Key Lab of Translational Medical Research in Cognitive Development and Learning and Memory Disorders and Ministry of Education Key Lab of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China; Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, The University of British Columbia, Vancouver, British Columbia, Canada.
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Malakooti N, Pritchard MA, Adlard PA, Finkelstein DI. Role of metal ions in the cognitive decline of Down syndrome. Front Aging Neurosci 2014; 6:136. [PMID: 25002847 PMCID: PMC4066992 DOI: 10.3389/fnagi.2014.00136] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 06/09/2014] [Indexed: 11/17/2022] Open
Abstract
Down syndrome (DS), caused by trisomy of whole or part of chromosome 21 is the most common mental impairment. All people with DS suffer from cognitive decline and develop Alzheimer’s disease (AD) by the age of 40. The appearance of enlarged early endosomes, followed by Amyloid βpeptide deposition, the appearance of tau-containing neurofibrillary tangles and basal forebrain cholinergic neuron (BFCN) degeneration are the neuropathological characteristics of this disease. In this review we will examine the role of metal ion dyshomeostasis and the genes which may be involved in these processes, and relate these back to the manifestation of age-dependent cognitive decline in DS.
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Affiliation(s)
- Nakisa Malakooti
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health Parkville, VIC, Australia
| | | | - Paul A Adlard
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health Parkville, VIC, Australia
| | - David I Finkelstein
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health Parkville, VIC, Australia
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Sun X, Wu Y, Herculano B, Song W. RCAN1 overexpression exacerbates calcium overloading-induced neuronal apoptosis. PLoS One 2014; 9:e95471. [PMID: 24751678 PMCID: PMC3994074 DOI: 10.1371/journal.pone.0095471] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 03/26/2014] [Indexed: 01/23/2023] Open
Abstract
Down Syndrome (DS) patients develop characteristic Alzheimer's Disease (AD) neuropathology after their middle age. Prominent neuronal loss has been observed in the cortical regions of AD brains. However, the underlying mechanism leading to this neuronal loss in both DS and AD remains to be elucidated. Calcium overloading and oxidative stress have been implicated in AD pathogenesis. Two major isoforms of regulator of calcineurin 1 (RCAN1), RCAN1.1 and RCAN1.4, are detected in human brains. In this report we defined the transcriptional regulation of RCAN1.1 and RCAN1.4 by two alternative promoters. Calcium overloading upregulated RCAN1.4 expression by activating RCAN1.4 promoter through calcineurin-NFAT signaling pathway, thus forming a negative feedback loop in isoform 4 regulation. Furthermore, RCAN1.4 overexpression exacerbated calcium overloading-induced neuronal apoptosis, which was mediated by caspase-3 apoptotic pathway. Our results suggest that downregulating RCAN1.4 expression in neurons could be beneficial to AD patients.
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Affiliation(s)
- Xiulian Sun
- Qilu Hospital of Shandong University, Jinan, China
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, The University of British Columbia, Vancouver, Canada
| | - Yili Wu
- Chongqing City Key Lab of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, and Ministry of Education Key Laboratory of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, The University of British Columbia, Vancouver, Canada
| | - Bruno Herculano
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, The University of British Columbia, Vancouver, Canada
| | - Weihong Song
- Chongqing City Key Lab of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, and Ministry of Education Key Laboratory of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, The University of British Columbia, Vancouver, Canada
- * E-mail:
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12
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Song WJ, Song EAC, Choi SH, Baik HH, Jin BK, Kim JH, Chung SH. Dyrk1A-mediated phosphorylation of RCAN1 promotes the formation of insoluble RCAN1 aggregates. Neurosci Lett 2013; 554:135-40. [PMID: 24021800 DOI: 10.1016/j.neulet.2013.08.066] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 08/13/2013] [Accepted: 08/29/2013] [Indexed: 12/21/2022]
Abstract
The mechanisms underlying aggregate formation in age-related neurodegenerative diseases remain not well understood. Here we investigated whether dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 1A (Dyrk1A) is involved in the formation of regulator of calcineurin 1 (RCAN1) aggregates. We show that RCAN1 self-associates and forms multimers, and that this process is promoted by the Dyrk1A-mediated phosphorylation of RCAN1 at the Thr(192) residue. Transgenic mice that overexpress the Dyrk1A exhibited lower levels of phospho-Thr(192)-RCAN1 in 10-month-old-group compared to littermate controls, when analyzed with soluble hippocampus lysates. These results suggest that the phosphorylation of RCAN1 by Dyrk1A stimulates the formation of insoluble aggregates upon aging.
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Affiliation(s)
- Woo-Joo Song
- Department of Biochemistry and Molecular Biology, Neurodegeneration Control Research Center, School of Medicine, Kyung Hee University, Seoul 130-701, Republic of Korea
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13
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Liu H, Tu L, Wang Q, Sun Y, Ma Y, Cen J, Wei Q, Luo J. Modulation of calcineurin activity in mouse brain by chronic oral administration of cyclosporine A. IUBMB Life 2013; 65:445-53. [DOI: 10.1002/iub.1139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 01/07/2013] [Indexed: 12/11/2022]
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14
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Covalent NEDD8 conjugation increases RCAN1 protein stability and potentiates its inhibitory action on calcineurin. PLoS One 2012; 7:e48315. [PMID: 23118980 PMCID: PMC3485183 DOI: 10.1371/journal.pone.0048315] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 09/24/2012] [Indexed: 12/27/2022] Open
Abstract
Similar to ubiquitin, regulatory roles for NEDD8 (neural precursor cell-expressed developmentally down-regulated 8) are being clarified during cell growth, signal transduction, immune response, and development. However, NEDD8 targets and their functional alterations are not well known. Regulator of calcineurin 1 (RCAN1/DSCR1P1) is located near the Down syndrome critical region on the distal part of chromosome 21, and its gene product is an endogenous inhibitor of calcineurin signaling. RCAN1 is modified by ubiquitin and consequently undergoes proteasomal degradation. Here we report that NEDD8 is conjugated to RCAN1 (RCAN1-1S) via three lysine residues, K96, K104, and K107. Neddylation enhances RCAN1 protein stability without affecting its cellular location. In addition, we found that neddylation significantly inhibits proteasomal degradation of RCAN1, which may underlie the ability of NEDD8 to enhance RCAN1 stability. Furthermore, neddylation increases RCAN1 binding to calcineurin, which potentiates its inhibitory activity toward downstream NFAT signaling. The present study provides a new regulatory mechanism of RCAN1 function and highlights an important role for diverse RCAN1-involved cellular physiology.
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15
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Xing L, Salas M, Zhang H, Gittler J, Ludwig T, Lin CS, Murty VV, Silverman W, Arancio O, Tycko B. Creation and characterization of BAC-transgenic mice with physiological overexpression of epitope-tagged RCAN1 (DSCR1). Mamm Genome 2012; 24:30-43. [PMID: 23096997 DOI: 10.1007/s00335-012-9436-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 09/10/2012] [Indexed: 11/29/2022]
Abstract
The chromosome 21 gene RCAN1, encoding a modulator of the calcineurin (CaN) phosphatase, is a candidate gene for contributing to cognitive disability in people with Down syndrome (DS; trisomy 21). To develop a physiologically relevant model for studying the biochemistry of RCAN1 and its contribution to DS, we generated bacterial artificial chromosome-transgenic (BAC-Tg) mouse lines containing the human RCAN1 gene with a C-terminal HA-FLAG epitope tag incorporated by recombineering. The BAC-Tg was expressed at levels only moderately higher than the native Rcan1 gene: approximately 1.5-fold in RCAN1 (BAC-Tg1) and twofold in RCAN1 (BAC-Tg2). Affinity purification of the RCAN1 protein complex from brains of these mice revealed a core complex of RCAN1 with CaN, glycogen synthase kinase 3-beta (Gsk3b), and calmodulin, with substoichiometric components, including LOC73419. The BAC-Tg mice are fully viable, but long-term synaptic potentiation is impaired in proportion to BAC-Tg dosage in hippocampal brain slices from these mice. RCAN1 can act as a tumor suppressor in some systems, but we found that the RCAN1 BAC-Tg did not reduce mammary cancer growth when present at a low copy number in Tp53;WAP-Cre mice. This work establishes a useful mouse model for investigating the biochemistry and dose-dependent functions of the RCAN1 protein in vivo.
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Affiliation(s)
- Luzhou Xing
- Institute for Cancer Genetics, Columbia University Medical Center, Herbert Irving Cancer Research Building, New York, NY 10032, USA
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16
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Chen CP, Chen YH, Chern SR, Chang SJ, Tsai TL, Li SH, Chou HC, Lo YW, Lyu PC, Chan HL. Placenta proteome analysis from Down syndrome pregnancies for biomarker discovery. MOLECULAR BIOSYSTEMS 2012; 8:2360-72. [PMID: 22777171 DOI: 10.1039/c2mb25081k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Down syndrome is one of the most frequent chromosomal disorders, with a prevalence of approximately 1/500 to 1/800, depending on the maternal age distribution of the pregnant population. However, few reliable protein biomarkers have been used in the diagnosis of this disease. Recent progress in quantitative proteomics has offered opportunities to discover biomarkers for tracking the progression and for understanding the molecular mechanisms of Down syndrome. In the present study, placental samples were analyzed by fluorescence two-dimensional differential gel electrophoresis (2D-DIGE) and differentially expressed proteins were identified by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). In total, 101 proteins have been firmly identified representing 80 unique gene products. These proteins mainly function in cytoskeleton structure and regulation (such as vimentin and Profilin-1). Additionally, our quantitative proteomics approach has identified numerous previously reported Down syndrome markers, such as myelin protein. Here we present several Down syndrome biomarkers including galectin-1, ataxin-3 and sprouty-related EVH1 domain-containing protein 2 (SPRED2), which have not been reported elsewhere and may be associated with the progression and development of the disease. In summary, we report a comprehensive placenta-based proteomics approach for the identification of potential biomarkers for Down syndrome, in which serum amyloid P-component (APCS) and ataxin-3 have been shown to be up-regulated in the maternal peripheral plasma of Down syndrome cases. The potential of utilizing these markers for the prognosis and screening of Down syndrome warrants further investigation.
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Affiliation(s)
- Chih-Ping Chen
- Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan
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17
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Kozyrev SV, Bernal-Quirós M, Alarcón-Riquelme ME, Castillejo-López C. The dual effect of the lupus-associated polymorphism rs10516487 on BANK1 gene expression and protein localization. Genes Immun 2011; 13:129-38. [PMID: 21900951 DOI: 10.1038/gene.2011.62] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Numerous loci have been found genetically associated with complex diseases, but only in a few cases has the functional variant and the molecular mechanism behind it been identified. Recently, the association of the BANK1 gene with systemic lupus erythematosus (SLE) was described. Here, we investigated the role of the associated polymorphisms on gene function and found that SNP rs17266594 located in the branch point consensus sequence has negligible effect on splicing or gene expression. The non-synonymous SNP rs10516487 located in exon 2 influenced splicing efficiency by creating an exonic splicing enhancer site for the SRp40 factor. Further, this same SNP generates protein isoforms with differential and measurable self-association properties. The full-length protein isoform containing the R61 variant forms larger protein scaffold complexes in the cell cytoplasm compared with the protective BANK1-61H variant. We also observed that, contrary to the full-length isoforms, the short Δ2 isoform of BANK1 displays a homogeneous cytoplasmic distribution, underscoring the potential role of the exon 2-coded protein domain in the scaffolding function of BANK1. We provide evidence that the non-synonymous SNP rs10516487 (G>A; R61H) shows a dual nature by first, influencing mRNA splicing and consequently the quantity of protein, and, second, by producing a risk variant-containing protein isoform with increased potential for multimerization.
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Affiliation(s)
- S V Kozyrev
- Department of Medical Biochemistry and Microbiology, BMC, Uppsala University, Uppsala, Sweden
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18
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Sun X, Wu Y, Chen B, Zhang Z, Zhou W, Tong Y, Yuan J, Xia K, Gronemeyer H, Flavell RA, Song W. Regulator of calcineurin 1 (RCAN1) facilitates neuronal apoptosis through caspase-3 activation. J Biol Chem 2011; 286:9049-62. [PMID: 21216952 DOI: 10.1074/jbc.m110.177519] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Individuals with Down syndrome (DS) will inevitably develop Alzheimer disease (AD) neuropathology sometime after middle age, which may be attributable to genes triplicated in individuals with DS. The characteristics of AD neuropathology include neuritic plaques, neurofibrillary tangles, and neuronal loss in various brain regions. The mechanism underlying neurodegeneration in AD and DS remains elusive. Regulator of calcineurin 1 (RCAN1) has been implicated in the pathogenesis of DS. Our data show that RCAN1 expression is elevated in the cortex of DS and AD patients. RCAN1 expression can be activated by the stress hormone dexamethasone. A functional glucocorticoid response element was identified in the RCAN1 isoform 1 (RCAN1-1) promoter region, which is able to mediate the up-regulation of RCAN1 expression. Here we show that overexpression of RCAN1-1 in primary neurons activates caspase-9 and caspase-3 and subsequently induces neuronal apoptosis. Furthermore, we found that the neurotoxicity of RCAN1-1 is inhibited by knock-out of caspase-3 in caspase-3(-/-) neurons. Our study provides a novel mechanism by which RCAN1 functions as a mediator of stress- and Aβ-induced neuronal death, and overexpression of RCAN1 due to an extra copy of the RCAN1 gene on chromosome 21 contributes to AD pathogenesis in DS.
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Affiliation(s)
- Xiulian Sun
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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19
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20
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Liu H, Wang P, Song W, Sun X. Degradation of regulator of calcineurin 1 (RCAN1) is mediated by both chaperone-mediated autophagy and ubiquitin proteasome pathways. FASEB J 2009; 23:3383-92. [PMID: 19509306 DOI: 10.1096/fj.09-134296] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Regulator of calcineurin 1 (RCAN1), a gene identified from the critical region of Down syndrome, has been implied in pathogenesis of Alzheimer's disease (AD). RCAN1 expression was shown to be increased in AD brains; however, the mechanism of RCAN1 gene regulation is not well defined. The present study was designed to investigate the molecular mechanism of RCAN1 protein degradation. In addition to being degraded through the ubiquitin proteasome pathway, we found that lysosomal inhibition markedly increased RCAN1 protein expression in a time- and dosage-dependent manner. Inhibition of macroautophagy reduced RCAN1 expression, indicating that RCAN1 degradation is not through a macroautophagy pathway. However, disruption of chaperone-mediated autophagy (CMA) increased RCAN1 expression. Two CMA recognition motifs were identified in RCAN1 protein to mediate its degradation through a CMA-lysosome pathway. A promoter assay further demonstrated that inhibition of RCAN1 degradation in cells reduced calcineurin-NFAT activity. Dysfunctions of ubiquitin-proteasome and autophagy-lysosome pathways have been implicated in neurodegenerative diseases. Therefore, elucidation of RCAN1 degradation by a ubiquitin proteasome pathway and CMA-lysosome pathway in the present study may greatly advance our understanding of AD pathogenesis.
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Affiliation(s)
- Heng Liu
- Qilu Hospital of Shandong University, Jinan, Shandong, China
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21
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Park J, Oh Y, Chung KC. Two key genes closely implicated with the neuropathological characteristics in Down syndrome: DYRK1A and RCAN1. BMB Rep 2009; 42:6-15. [PMID: 19192387 DOI: 10.5483/bmbrep.2009.42.1.006] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The most common genetic disorder Down syndrome (DS) displays various developmental defects including mental retardation, learning and memory deficit, the early onset of Alzheimer's disease (AD), congenital heart disease, and craniofacial abnormalities. Those characteristics result from the extra-genes located in the specific region called nDown syndrome critical region (DSCR)' in human chromosome 21. In this review, we summarized the recent findings of the DYRK1A and RCAN1 genes, which are located on DSCR and thought to be closely associated with the typical features of DS patients, and their implication to the pathogenesis of neural defects in DS. DYRK1A phosphorylates several transcriptional factors, such as CREB and NFAT, endocytic complex proteins, and AD-linked gene products. Meanwhile, RCAN1 is an endogenous inhibitor of calcineurin A, and its unbalanced activity is thought to cause major neuronal and/or non-neuronal malfunction in DS and AD. Interestingly, they both contribute to the learning and memory deficit, altered synaptic plasticity, impaired cell cycle regulation, and AD-like neuropathology in DS. By understanding their biochemical, functional and physiological roles, we hope to get important molecular basis of DS pathology, which would consequently lead to the basis to develop the possible therapeutic tools for the neural defects in DS. [BMB reports 2009; 42(1): 6-15].
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Affiliation(s)
- Joongkyu Park
- Department of Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
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22
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CREB activates proteasomal degradation of DSCR1/RCAN1. FEBS Lett 2008; 582:1889-93. [PMID: 18485898 DOI: 10.1016/j.febslet.2008.04.059] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Accepted: 04/18/2008] [Indexed: 10/22/2022]
Abstract
The cyclic AMP response element-binding protein (CREB) is involved in the development and function of the nervous system. Here, we find that CREB decreases the protein level of Regulator of Calcineurin Activity 1 (RCAN1/DSCR1/MCIP1), which is overexpressed in the brain of Down Syndrome (DS) patients. Decrease of RCAN1 by CREB was blocked by proteasome inhibitors, indicating that this decrease is mediated by the ubiquitin-proteasome pathway. Furthermore, we found that the ability of CREB to activate the degradation of RCAN1 depends on its transcriptional activation. Consistently, CREB-enhanced the ubiquitination and turnover rate of RCAN1. Our results reveal a new regulatory role for CREB in DS pathology through the proteasomal degradation of RCAN1.
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Mental retardation and associated neurological dysfunctions in Down syndrome: a consequence of dysregulation in critical chromosome 21 genes and associated molecular pathways. Eur J Paediatr Neurol 2008; 12:168-82. [PMID: 17933568 DOI: 10.1016/j.ejpn.2007.08.010] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Revised: 08/19/2007] [Accepted: 08/21/2007] [Indexed: 12/11/2022]
Abstract
Down syndrome (DS), affecting 1/700 live births, is the major genetic cause of mental retardation (MR), a cognitive disorder with hard impact on public health. DS brain is characterized by a reduced cerebellar volume and number of granular cells, defective cortical lamination and reduced cortical neurons, malformed dendritic trees and spines, and abnormal synapses. These neurological alterations, also found in trisomic mouse models, result from gene-dosage effects of Human Chromosome 21 (HC21) on the expression of critical developmental genes. HC21 sequencing, mouse ortholog gene identification and DS mouse model generation lead to determine HC21 gene functions and the effects of protein-dosage alterations in neurodevelopmental and metabolic pathways in DS individuals. Trisomic brain transcriptome of DS patients and trisomic mouse models identified some molecular changes determined by gene-overdosage and associated dysregulation of some disomic gene expression in DS brains. These transcriptional variations cause developmental alterations in neural patterning and signal transduction pathways that may lead to defective neuronal circuits responsible for the pathogenesis of MR in DS. Recently, the first altered molecular pathway responsible of some DS phenotypes, including neurological and cognitive disorders has been identified. In this pathway, two critical HC21 genes (DYRK1A and DSCR1) act synergistically to control the phosphorylation levels of NFATc and NFATc-regulated gene expression. Interestingly, the NFATc mice show neurological dysfunctions similar to those seen in DS patients and trisomic mouse models. Treatment of DS mouse model Ts65Dn with GABA(A) antagonists allowed post-drug rescue of cognitive defects, indicating a hopeful direction in clinical therapies for MR in children with DS.
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Keating DJ, Dubach D, Zanin MP, Yu Y, Martin K, Zhao YF, Chen C, Porta S, Arbonés ML, Mittaz L, Pritchard MA. DSCR1/RCAN1 regulates vesicle exocytosis and fusion pore kinetics: implications for Down syndrome and Alzheimer's disease. Hum Mol Genet 2008; 17:1020-30. [PMID: 18180251 DOI: 10.1093/hmg/ddm374] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Genes located on chromosome 21, over-expressed in Down syndrome (DS) and Alzheimer's disease (AD) and which regulate vesicle trafficking, are strong candidates for involvement in AD neuropathology. Regulator of calcineurin activity 1 (RCAN1) is one such gene. We have generated mutant mice in which RCAN1 is either over-expressed (RCAN1(ox)) or ablated (Rcan1-/-) and examined whether exocytosis from chromaffin cells, a classic cellular model of neuronal exocytosis, is altered using carbon fibre amperometry. We find that Rcan1 regulates the number of vesicles undergoing exocytosis and the speed at which the vesicle fusion pore opens and closes. Cells from both Rcan1-/- and RCAN1(ox) mice display reduced levels of exocytosis. Changes in single-vesicle fusion kinetics are also evident resulting in the less catecholamine released per vesicle with increasing Rcan1 expression. Acute calcineurin inhibition did not replicate the effect of RCAN1 overexpression. These changes are not due to alterations in Ca2+ entry or the readily releasable vesicle pool size. Thus, we illustrate a novel regulator of vesicle exocytosis, Rcan1, which influences both exocytotic rate and vesicle fusion kinetics. If Rcan1 functions similarly in neurons then overexpression of this protein, as occurs in DS and AD brains, will reduce both the number of synaptic vesicles undergoing exocytosis and the amount of neurotransmitter released per fusion event. This has direct implications for the pathogenesis of these diseases as sufficient levels of neurotransmission are required for synaptic maintenance and the prevention of neurodegeneration and vesicle trafficking defects are the earliest hallmark of AD neuropathology.
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Affiliation(s)
- Damien J Keating
- Molecular and Cellular Neuroscience Group, Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, Australia
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25
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Nuclear protein contents in peripheral blood mononuclear cells of trisomy 21 infants. CYTOMETRY PART B-CLINICAL CYTOMETRY 2008; 74:128-32. [DOI: 10.1002/cyto.b.20387] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Porta S, Martí E, de la Luna S, Arbonés ML. Differential expression of members of the RCAN family of calcineurin regulators suggests selective functions for these proteins in the brain. Eur J Neurosci 2007; 26:1213-26. [PMID: 17767500 DOI: 10.1111/j.1460-9568.2007.05749.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
RCANs, also called Down Syndrome Critical Region-1 (DSCR1)-like proteins, Modulatory Calcineurin Interacting Proteins (MCIPs) or calcipressins, are regulators of calcineurin, a Ca(2+)-dependent protein phosphatase involved in several neuronal functions. Despite the potential importance of the RCAN proteins in brain physiology, very little is known about their relative abundance and distribution patterns in the central nervous system. In this study we report the expression and distribution of RCAN mRNA transcripts and proteins in the mouse brain. RT-PCR and Western blot analysis showed that all Rcan mRNAs (Rcan1-1, Rcan1-2, Rcan2-1, Rcan2-3 and Rcan3) and their corresponding protein products (RCAN1-L, RCAN1-S, RCAN2-L, RCAN2-S and RCAN3) are present in every adult mouse brain region examined. All protein isoforms are also expressed in these same brain regions at early postnatal stages. Within regions, RCAN1-L, RCAN1-S, RCAN2-L and RCAN3 are differentially expressed depending on the region and developmental stage, whereas RCAN2-S is distributed homogeneously. Detailed immunohistochemical analysis revealed significant differences in the cellular and subcellular distributions of RCAN proteins. In the adult, RCAN1 was mainly expressed in the neuropil throughout the brain. Although at lower levels, RCAN3 was also detected throughout the neuropil. In contrast, RCAN2 was highly expressed in scattered neurons, in both the nucleus and the cytoplasm. Interestingly, RCAN2 is the only member of the RCAN family that was detected in glial cells. Finally, the expression patterns of RCANs at early postnatal stages differed from those of the adult, in different brain areas, in both their distributions and relative abundance, suggesting that the expression of these proteins could be regulated during neuronal differentiation. The nonoverlapping expression patterns of the RCAN proteins shown here highlight the existence of different physiological scenarios and therefore suggest different RCAN functional activities in the brain, depending on the cellular context and developmental stage.
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Affiliation(s)
- Sílvia Porta
- Center for Genomic Regulation (CRG), UPF, Dr Aiguader 88, E-08003 Barcelona, Spain
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27
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The SCFCdc4 ubiquitin ligase regulates calcineurin signaling through degradation of phosphorylated Rcn1, an inhibitor of calcineurin. Proc Natl Acad Sci U S A 2007; 104:17418-23. [PMID: 17954914 DOI: 10.1073/pnas.0704951104] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The highly conserved RCN family of proteins regulates the serine/threonine protein phosphatase calcineurin, which is required for the expression of genes involved in Ca(2+)-dependent processes, such as the control of memory, apoptosis, T cell activation, cell cycle, Ca(2+)-homeostasis, and skeletal and cardiac muscle growth and differentiation. However, RCNs regulate calcineurin through two paradoxical actions: they act as feedback inhibitors of calcineurin, whereas their phosphorylation stimulates calcineurin. Here we show that phosphorylation of yeast RCN, Rcn1, triggers degradation through the SCF(Cdc4) ubiquitin ligase complex. Degradation of phosphorylated Rcn1 is required to mitigate inhibition of calcineurin by Rcn1 and results in activation of calcineurin activity in response to Ca(2+) as well as in reactivation of calcineurin in response to changes in Ca(2+) concentration. The SCF(Cdc4)-dependent degradation required phosphorylation of Rcn1 by Mck1, a member of the GSK3 family of protein kinases, and was promoted by Ca(2+). However, such degradation was counteracted by dephosphorylation of Rcn1, which was promoted by Ca(2+)-stimulated calcineurin. Thus, calcineurin activity is fine-tuned to Ca(2+) signals by mechanisms that have opposite functions. Our results identify the molecular mechanism of Rcn1 phosphorylation-induced stimulation of the phosphatase activity of calcineurin. The results provide insight into the mechanism involved in maintaining proper responses to Ca(2+) signals.
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Lee EJ, Lee JY, Seo SR, Chung KC. Overexpression of DSCR1 blocks zinc-induced neuronal cell death through the formation of nuclear aggregates. Mol Cell Neurosci 2007; 35:585-95. [PMID: 17596961 DOI: 10.1016/j.mcn.2007.05.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 05/09/2007] [Accepted: 05/09/2007] [Indexed: 11/22/2022] Open
Abstract
The Down syndrome (DS) candidate region gene 1 (DSCR1) is localized near DS critical region on chromosome 21 and is overexpressed in the brains of DS patients. Although DSCR1 was known for a modulator of calcineurin, the overexpression of DSCR1 is thought to play a role in neuronal cell death. Zinc, one of the most abundant transition metals in the brain, may also contribute to selective neuronal cell death when present in excessive amounts. In the present study, we investigated the effect of DSCR1 overexpression on zinc-induced cell death in hippocampal neuroprogenitor cells. The overexpression of DSCR1 caused apoptotic cell death without an apparent formation of intracellular protein inclusions. Upon exposure to zinc, soluble DSCR1 levels were significantly decreased and insoluble levels were enhanced to a similar extent, which were partially caused by the zinc-induced inhibition of proteasomal activity and a consequently diminished degradation of DSCR1. Furthermore, zinc treatment induced the formation of nuclear DSCR1 aggregates, which blocked zinc-induced cell death. These findings indicate that, although the up-regulation of DSCR1 levels exerts a cytotoxic effect, the addition of zinc leads to the formation of cytoprotective nuclear aggregates in neuronal cells.
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Affiliation(s)
- Eun Jung Lee
- Department of Biology, College of Science, Yonsei University, Shinchon-dong 134, Seodaemun-gu, Seoul 120-749, Republic of Korea
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29
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Rujano MA, Bosveld F, Salomons FA, Dijk F, van Waarde MA, van der Want JJ, de Vos RA, Brunt ER, Sibon OC, Kampinga HH. Polarised asymmetric inheritance of accumulated protein damage in higher eukaryotes. PLoS Biol 2007; 4:e417. [PMID: 17147470 PMCID: PMC1750924 DOI: 10.1371/journal.pbio.0040417] [Citation(s) in RCA: 193] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Accepted: 10/02/2006] [Indexed: 12/29/2022] Open
Abstract
Disease-associated misfolded proteins or proteins damaged due to cellular stress are generally disposed via the cellular protein quality-control system. However, under saturating conditions, misfolded proteins will aggregate. In higher eukaryotes, these aggregates can be transported to accumulate in aggresomes at the microtubule organizing center. The fate of cells that contain aggresomes is currently unknown. Here we report that cells that have formed aggresomes can undergo normal mitosis. As a result, the aggregated proteins are asymmetrically distributed to one of the daughter cells, leaving the other daughter free of accumulated protein damage. Using both epithelial crypts of the small intestine of patients with a protein folding disease and Drosophila melanogaster neural precursor cells as models, we found that the inheritance of protein aggregates during mitosis occurs with a fixed polarity indicative of a mechanism to preserve the long-lived progeny. Human cells containing polyglutamine damage enter mitosis and complete cytokinesis. The association of aggresomes with one centrosome means that accumulated damage is asymmetrically inherited in only one daughter cell.
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Affiliation(s)
- María A Rujano
- Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Floris Bosveld
- Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Florian A Salomons
- Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Freark Dijk
- Department of Cell Biology, Section of Electron Microscopy, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Maria A.W.H van Waarde
- Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Johannes J.L van der Want
- Department of Cell Biology, Section of Electron Microscopy, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Rob A.I de Vos
- Pathology Laboratory Oost Nederland, Enschede, The Netherlands
| | - Ewout R Brunt
- Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Ody C.M Sibon
- Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Harm H Kampinga
- Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
- * To whom correspondence should be addressed. E-mail:
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30
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Porta S, Serra SA, Huch M, Valverde MA, Llorens F, Estivill X, Arbonés ML, Martí E. RCAN1 (DSCR1) increases neuronal susceptibility to oxidative stress: a potential pathogenic process in neurodegeneration. Hum Mol Genet 2007; 16:1039-50. [PMID: 17341486 DOI: 10.1093/hmg/ddm049] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Oxidative stress (OS) underlies neuronal dysfunction in many neurodegenerative disorders. Regulator of Calcineurin 1 (RCAN1 or DSCR1) is a dose-sensitive gene whose overexpression has been linked to Down syndrome (DS) and Alzheimer's disease (AD) neuropathology and to the response of cells to stress stimuli. Here, we show that RCAN1 mRNA and protein expression are sensitive to OS in primary neurons, and we evaluate the involvement of RCAN1 dosage in neuronal death induced by OS. We find that Rcan1(-/-) neurons display an increased resistance to damage by H(2)O(2), which can be reverted by RCAN1 overexpression or by exogenous inhibitors of calcineurin. Although increased intracellular Ca(2+) concentration is an important factor in OS-mediated cell death, our results show that Ca(2+) loading after exposure to H(2)O(2) was similar in Rcan1(+/+) and Rcan1(-/-) neurons. Our data further suggest that CaN and NFAT signaling protect against OS in both Rcan1(+/+) and Rcan1(-/-) neurons. To explain the observed differential vulnerability, we therefore propose a mechanism downstream of H(2)O(2)-mediated Ca(2+) entry, involving calcineurin-NFAT signaling. These findings highlight the importance of RCAN1 gene dosage in the modulation of cell survival and death pathways and suggest that changes in the amount of RCAN1 could represent an important mechanism for regulating susceptibility to neurodegeneration, especially in DS and AD.
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Affiliation(s)
- Sílvia Porta
- Genes and Disease Program, Center for Genomic Regulation (CRG-UPF), Biomedical Research Park Building, E-08003 Barcelona, Catalonia, Spain
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Keating DJ, Chen C, Pritchard MA. Alzheimer's disease and endocytic dysfunction: clues from the Down syndrome-related proteins, DSCR1 and ITSN1. Ageing Res Rev 2006; 5:388-401. [PMID: 16442855 DOI: 10.1016/j.arr.2005.11.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Revised: 11/19/2005] [Accepted: 11/28/2005] [Indexed: 10/25/2022]
Abstract
Down syndrome (DS) is a genetically-based disorder which results in multiple conditions for sufferers. Amongst these is a common early incidence of Alzheimer's disease (AD) which usually affects DS individuals by their mid 40s. This fact provides a clue that one or more of the genes located on chromosome 21 may be involved in the onset of AD. Current evidence suggests that endosomal disorders may underlie the earliest pathology of AD, preceding the classical pathological markers of beta-amyloid plaque deposition and neurofibrillary tangles. Therefore, any genes involved in endocytosis and vesicle trafficking which are over-expressed in DS are novel candidates in the pathogenesis of AD. Intersectin-1 (ITSN1) and Down syndrome candidate region 1 (DSCR1) are two such genes. Extensive in vitro data and data from Drosophila indicates that the over-expression of either of these genes or their products results in inhibition or ablation of endocytosis in neuronal as well as non-neuronal cells. This review discusses in detail the known and potential roles of ITSN1 and DSCR1 in DS, AD, endocytosis and vesicle trafficking.
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Affiliation(s)
- Damien J Keating
- Prince Henry's Institute of Medical Research, Clayton, Vic., Australia
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Miller RM, Kiser GL, Kaysser-Kranich TM, Lockner RJ, Palaniappan C, Federoff HJ. Robust dysregulation of gene expression in substantia nigra and striatum in Parkinson's disease. Neurobiol Dis 2006; 21:305-13. [PMID: 16143538 DOI: 10.1016/j.nbd.2005.07.010] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Revised: 07/11/2005] [Accepted: 07/18/2005] [Indexed: 02/02/2023] Open
Abstract
Large-scale genomics approaches are now widely utilized to study a myriad of human diseases. These powerful techniques, when combined with data analysis tools, detect changes in transcript abundance in diseased tissue relative to control. We hypothesize that specific differential gene expression underlies important pathogenic processes in Parkinson's disease, which is characterized by the gradual loss of dopaminergic neurons in the substantia nigra and consequent loss of dopamine in the striatum. We have therefore examined gene expression levels in the human parkinsonian nigrostriatal pathway, and compared them with those of neurologically normal controls. Using unsupervised clustering methods, we demonstrate that relatively few genes' expression levels can effectively distinguish between disease and control brains. Further, we identify several interesting patterns of gene expression that illuminate pathogenic cascades in Parkinson's disease. In particular is the robust loss of synaptic gene expression in diseased substantia nigra and striatum.
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Affiliation(s)
- Renee M Miller
- Center for Aging and Developmental Biology, Aab Institute of Biomedical Sciences, University of Rochester, Box 645, 601 Elmwood Avenue, Rochester, NY 14642, USA
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Miller RM, Federoff HJ. Altered gene expression profiles reveal similarities and differences between Parkinson disease and model systems. Neuroscientist 2006; 11:539-49. [PMID: 16282595 DOI: 10.1177/1073858405278330] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Parkinson disease (PD) targets dopaminergic neurons in the substantia nigra, resulting in motor disturbances such as resting tremor, bradykinesia, and rigidity. Pathogenic processes likely occur over several decades, in that an overwhelming percentage of neurons are already dead at the time of clinical diagnosis. For this reason, the usage of animal model systems to discover the early steps in the pathologic cascade is required. These include exposure to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which selectively kills dopamine neurons in the substantia nigra, and genetic models incorporating mutations in the alpha-synuclein gene that cause disease in human patients. Through the evaluation of these models at multiple time points, it is possible to discover novel gene expression changes that may underlie disease pathogenesis. Specifically, the authors hypothesize that animal models of PD and human PD brains share a gene expression profile that signifies certain aspects of pathogenesis and/or recovery-resistance. To test this and similar hypotheses, the authors and others have utilized new microarray technology that enables the sampling of thousands of genes' expression level in one assay. Because the technology is fairly new and results can vary depending on methods used, results must be evaluated with care. Multiple array and data-mining options can be used to make the most accurate inferences as to differentially expressed genes in each set of samples. The authors developed a fusion classifier approach whereby individual data-mining algorithms generate lists of significant genes. The lists are subsequently queried, and only genes unanimously called significant are retained for further validation. Although the authors' approach identified hundreds of differentially expressed genes in each of three PD systems, only a few were common between the human and animal substantia nigra. These were related to dopamine phenotype, synaptic function, and the mitochondrial metabolism, implicating the presynaptic terminal as a primary site of injury. The time course of the authors' experiments indicates that if the synaptic changes could be prevented, this may alleviate some cell death, in that these changes precede neuronal loss.
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Affiliation(s)
- Renee M Miller
- Center for Aging and Developmental Biology, Aab Institute of Biomedical Sciences, Department of Neurology and University of Rochester School of Medicine and Dentistry, NY 14642, USA
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Chan B, Greenan G, McKeon F, Ellenberger T. Identification of a peptide fragment of DSCR1 that competitively inhibits calcineurin activity in vitro and in vivo. Proc Natl Acad Sci U S A 2005; 102:13075-80. [PMID: 16131541 PMCID: PMC1201586 DOI: 10.1073/pnas.0503846102] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Calcineurin phosphatase activity regulates the nuclear localization of the nuclear factor of activated T cells (NFAT) family of transcription factors during immune challenge. Calcineurin inhibitors, such as the cyclosporin A-cyclophilin A and FK506-FKBP12 complexes, regulate this enzymatic activity noncompetitively by binding at a site distinct from the enzyme active site. A family of endogenous protein inhibitors of calcineurin was recently identified and shown to block calcineurin-mediated NFAT nuclear localization and transcriptional activation. One such inhibitor, Down Syndrome Critical Region 1 (DSCR1), functions in T cell activation, cardiac hypertrophy, and angiogenesis. We have identified a small region of DSCR1 that is a potent inhibitor of calcineurin activity in vitro and in vivo.
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Affiliation(s)
- Betty Chan
- Department of Biological Chemistry, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
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Cano E, Canellada A, Minami T, Iglesias T, Redondo JM. Depolarization of neural cells induces transcription of the Down syndrome critical region 1 isoform 4 via a calcineurin/nuclear factor of activated T cells-dependent pathway. J Biol Chem 2005; 280:29435-43. [PMID: 15975916 DOI: 10.1074/jbc.m506205200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
In this study we showed that the transcriptional regulation of Down syndrome critical region isoform 4 (DSCR1.4) is mediated by the calcineurin/nuclear factor of activated T cells (NFAT) pathway in neural cells. Stimuli that elicit an increase in the intracellular concentrations of calcium, such as membrane depolarization, induced de novo transcription of DSCR1.4, with mRNA expression peaking after 4 h and then declining. Action via the physiologically relevant L-type calcium channel was confirmed by blockade with nifedipine and verapamil. This calcium-dependent transcription of DSCR1.4 was inhibited by the calcineurin inhibitors cyclosporin A and FK506. Deletional analysis showed that the calcium- and calcineurin-dependent activation is mediated by the promoter region between nucleotides -350 and -166, a region that contains putative NFAT-binding motifs. Exogenous NFATc2 potently augmented the DSCR1.4 promoter transcriptional activity, and the involvement of endogenous NFAT signaling pathway in DSCR1.4 transcription was confirmed by the suppression of depolarization-inducible promoter activity with the NFAT inhibitor peptide VIVIT. Exogenous overexpression of DSCR1 protein (calcipressin 1) resulted in the inhibition of the transcription of DSCR1.4 and NFAT-dependent signaling. These findings suggest that calcineurin-dependent induction of DSCR1.4 product may represent an important auto-regulatory mechanism for the homeostatic control of NFAT signaling in neural cells.
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Affiliation(s)
- Eva Cano
- Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
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Yao YG, Duh EJ. VEGF selectively induces Down syndrome critical region 1 gene expression in endothelial cells: a mechanism for feedback regulation of angiogenesis? Biochem Biophys Res Commun 2004; 321:648-56. [PMID: 15358155 DOI: 10.1016/j.bbrc.2004.06.176] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2004] [Indexed: 11/30/2022]
Abstract
The Down syndrome critical region 1 (DSCR1) gene (also known as MCIP1, Adapt78) encodes a regulatory protein that binds to calcineurin catalytic A subunit and acts as a regulator of the calcineurin-mediated signaling pathway. We show in this study that DSCR1 is greatly induced in endothelial cells in response to VEGF, TNF-alpha, and A23187 treatment, and that this up-regulation is inhibited by inhibitors of the calcineurin-NFAT (nuclear factor of activated T cells) signaling pathway as well as by PKC inhibition and a Ca(2+) chelator. We hypothesized that the up-regulation of DSCR1 gene expression in endothelial cells could act as an endogenous feedback inhibitor for angiogenesis by regulating the calcineurin-NFAT signaling pathway. Our transient transfection analyses confirm that the overexpression of DSCR1 abrogates the up-regulation of reporter gene expression driven by both the cyclooxygenase 2 and DSCR1 promoters in response to stimulators. Our results indicate that DSCR1 up-regulation may represent a potential molecular mechanism underlying the regulation of angiogenic genes activated by the calcineurin-NFAT signaling pathway in endothelial cells.
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Affiliation(s)
- Yong-Gang Yao
- Department of Ophthalmology, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA
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