1
|
Yu D, Wang H, Lei Z, Zhai Y, Chen S, Sun M, Yin P, Wang X. Analysis of differentially expressed genes discovers Latroeggtoxin VI-induced changes and SYNJ1 as a main target in PC12 cells. BMC Genomics 2023; 24:517. [PMID: 37667188 PMCID: PMC10478359 DOI: 10.1186/s12864-023-09634-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 08/29/2023] [Indexed: 09/06/2023] Open
Abstract
BACKGROUND Previous preliminary work found that Latroeggtoxin-VI (LETX-VI), a proteinaceous neurotoxin from the eggs of spider Latrodectus tredecimguttatus, could promote the synthesis and release of dopamine in PC12 cells. However, the underlying mechanisms have not been fully clear. Here, the effects of LETX-VI on the gene expression profile and dopamine in PC12 cells were analyzed with the differential transcriptome-based strategies. RESULTS After treatment of PC12 cells with LETX-VI for 24 h, a total of 356 differentially expressed transcripts were identified. Of them 165 were up-regulated and 191 down-regulated. Relevant GO analysis indicated that LETX-VI modulated the expression of certain genes and thereby affected multiple biological processes in PC12 cells, including protein metabolism, nucleic acid metabolism, substance transport, signaling, neurotransmitter metabolism and release. When western blot analysis was employed to confirm the abundance levels of synaptojanin 1 and synuclein alpha interacting protein, the representatives of highly up- and down-regulated transcript-encoded proteins that are closely related with dopamine respectively, it was found that the level of synaptojanin 1 in the PC12 cells treated with LETX-VI was increased, whereas that of synuclein alpha interacting protein was not obviously altered, suggesting that synaptojanin 1 may be much more involved in the effects of LETX-VI on dopamine. After synaptojanin 1 level was knocked down using siRNA, the levels of both total and released dopamine were significantly decreased, indicating that synaptojanin 1 is a protein positively modulating the synthesis and secretion of dopamine. When the PC12 cells with knocked down synaptojanin 1 were treated by LETX-VI, the adverse effects of synaptojanin 1 knockdown on dopamine were attenuated, confirming that LETX-VI promotes the synthesis and secretion of dopamine at least partially by enhancing the expression of the gene SYNJ1 encoding synaptojanin 1. CONCLUSIONS This work demonstrates that LETX-VI exerts multiple regulatory effects on the cellular processes in PC12 cells by altering the gene expression profile. LETX-VI modulates the expression of the genes closely related to the synthesis, transport and release of neurotransmitters especially dopamine in PC12 cells, with the gene SYNJ1 encoding synaptojanin 1 as a main target.
Collapse
Affiliation(s)
- Dianmei Yu
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Haiyan Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Zhixiang Lei
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Yiwen Zhai
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Si Chen
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Minglu Sun
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Panfeng Yin
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Xianchun Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China.
| |
Collapse
|
2
|
Choong CJ, Aguirre C, Kakuda K, Beck G, Nakanishi H, Kimura Y, Shimma S, Nabekura K, Hideshima M, Doi J, Yamaguchi K, Nakajima K, Wadayama T, Hayakawa H, Baba K, Ogawa K, Takeuchi T, Badawy SMM, Murayama S, Nagano S, Goto Y, Miyanoiri Y, Nagai Y, Mochizuki H, Ikenaka K. Phosphatidylinositol-3,4,5-trisphosphate interacts with alpha-synuclein and initiates its aggregation and formation of Parkinson's disease-related fibril polymorphism. Acta Neuropathol 2023; 145:573-595. [PMID: 36939875 PMCID: PMC10119223 DOI: 10.1007/s00401-023-02555-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 03/21/2023]
Abstract
Lipid interaction with α-synuclein (αSyn) has been long implicated in the pathogenesis of Parkinson's disease (PD). However, it has not been fully determined which lipids are involved in the initiation of αSyn aggregation in PD. Here exploiting genetic understanding associating the loss-of-function mutation in Synaptojanin 1 (SYNJ1), a phosphoinositide phosphatase, with familial PD and analysis of postmortem PD brains, we identified a novel lipid molecule involved in the toxic conversion of αSyn and its relation to PD. We first established a SYNJ1 knockout cell model and found SYNJ1 depletion increases the accumulation of pathological αSyn. Lipidomic analysis revealed SYNJ1 depletion elevates the level of its substrate phosphatidylinositol-3,4,5-trisphosphate (PIP3). We then employed Caenorhabditis elegans model to examine the effect of SYNJ1 defect on the neurotoxicity of αSyn. Mutations in SYNJ1 accelerated the accumulation of αSyn aggregation and induced locomotory defects in the nematodes. These results indicate that functional loss of SYNJ1 promotes the pathological aggregation of αSyn via the dysregulation of its substrate PIP3, leading to the aggravation of αSyn-mediated neurodegeneration. Treatment of cultured cell line and primary neurons with PIP3 itself or with PIP3 phosphatase inhibitor resulted in intracellular formation of αSyn inclusions. Indeed, in vitro protein-lipid overlay assay validated that phosphoinositides, especially PIP3, strongly interact with αSyn. Furthermore, the aggregation assay revealed that PIP3 not only accelerates the fibrillation of αSyn, but also induces the formation of fibrils sharing conformational and biochemical characteristics similar to the fibrils amplified from the brains of PD patients. Notably, the immunohistochemical and lipidomic analyses on postmortem brain of patients with sporadic PD showed increased PIP3 level and its colocalization with αSyn. Taken together, PIP3 dysregulation promotes the pathological aggregation of αSyn and increases the risk of developing PD, and PIP3 represents a potent target for intervention in PD.
Collapse
Affiliation(s)
- Chi-Jing Choong
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - César Aguirre
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Keita Kakuda
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Goichi Beck
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | | | - Yasuyoshi Kimura
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Shuichi Shimma
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Kei Nabekura
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Makoto Hideshima
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Junko Doi
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Keiichi Yamaguchi
- Global Center for Medical Engineering and Informatics, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Kichitaro Nakajima
- Global Center for Medical Engineering and Informatics, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Tomoya Wadayama
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hideki Hayakawa
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Kousuke Baba
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Kotaro Ogawa
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Toshihide Takeuchi
- Department of Neurology, Kindai University, 3-4-1 Kowakae, Higashiosaka City, Osaka, 577-8502, Japan
| | - Shaymaa Mohamed Mohamed Badawy
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.,Department of Agricultural Biochemistry, Faculty of Agriculture, Zagazig University, Zagazig, Egypt
| | - Shigeo Murayama
- Brain Bank for Neurodevelopmental, Neurological and Psychiatric Disorders, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Seiichi Nagano
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yuji Goto
- Global Center for Medical Engineering and Informatics, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yohei Miyanoiri
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoshitaka Nagai
- Department of Neurology, Kindai University, 3-4-1 Kowakae, Higashiosaka City, Osaka, 577-8502, Japan
| | - Hideki Mochizuki
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Kensuke Ikenaka
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| |
Collapse
|
3
|
Jr RH, Dang LH, Chen J, Lee JH, Marquer C. Triplication of Synaptojanin 1 in Alzheimer's Disease Pathology in Down Syndrome. Curr Alzheimer Res 2022; 19:CAR-EPUB-127977. [PMID: 36464875 DOI: 10.2174/1567205020666221202102832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 10/29/2022] [Accepted: 11/02/2022] [Indexed: 12/12/2022]
Abstract
Down Syndrome (DS), caused by triplication of human chromosome 21 (Hsa21) is the most common form of intellectual disability worldwide. Recent progress in healthcare has resulted in a dramatic increase in the lifespan of individuals with DS. Unfortunately, most will develop Alzheimer's disease like dementia (DS-AD) as they age. Understanding similarities and differences between DS-AD and the other forms of the disease - i.e., late-onset AD (LOAD) and autosomal dominant AD (ADAD) - will provide important clues for the treatment of DS-AD. In addition to the APP gene that codes the precursor of the main component of amyloid plaques found in the brain of AD patients, other genes on Hsa21 are likely to contribute to disease initiation and progression. This review focuses on SYNJ1, coding the phosphoinositide phosphatase synaptojanin 1 (SYNJ1). First, we highlight the function of SYNJ1 in the brain. We then summarize the involvement of SYNJ1 in the different forms of AD at the genetic, transcriptomic, proteomic and neuropathology levels in humans. We further examine whether results in humans correlate with what has been described in murine and cellular models of the disease and report possible mechanistic links between SYNJ1 and the progression of the disease. Finally, we propose a set of questions that would further strengthen and clarify the role of SYNJ1 in the different forms of AD.
Collapse
Affiliation(s)
- Robert Hwang Jr
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York City, NY 10032, USA
| | - Lam-Ha Dang
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York City, NY 10032, USA
- G. H. Sergievsky Center, Columbia University Medical Center, New York, NY 10032, USA
- Departments of Epidemiology and Neurology, Columbia University Medical Center, New York, NY 10032, USA
| | - Jacinda Chen
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York City, NY 10032, USA
| | - Joseph H Lee
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York City, NY 10032, USA
- G. H. Sergievsky Center, Columbia University Medical Center, New York, NY 10032, USA
- Departments of Epidemiology and Neurology, Columbia University Medical Center, New York, NY 10032, USA
| | - Catherine Marquer
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York City, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York City, NY 10032, USA
| |
Collapse
|
4
|
Amodio G, Moltedo O, Fasano D, Zerillo L, Oliveti M, Di Pietro P, Faraonio R, Barone P, Pellecchia MT, De Rosa A, De Michele G, Polishchuk E, Polishchuk R, Bonifati V, Nitsch L, Pierantoni GM, Renna M, Criscuolo C, Paladino S, Remondelli P. PERK-Mediated Unfolded Protein Response Activation and Oxidative Stress in PARK20 Fibroblasts. Front Neurosci 2019; 13:673. [PMID: 31316342 PMCID: PMC6610533 DOI: 10.3389/fnins.2019.00673] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 06/12/2019] [Indexed: 12/20/2022] Open
Abstract
PARK20, an early onset autosomal recessive parkinsonism is due to mutations in the phosphatidylinositol-phosphatase Synaptojanin 1 (Synj1). We have recently shown that the early endosomal compartments are profoundly altered in PARK20 fibroblasts as well as the endosomal trafficking. Here, we report that PARK20 fibroblasts also display a drastic alteration of the architecture and function of the early secretory compartments. Our results show that the exit machinery from the Endoplasmic Reticulum (ER) and the ER-to-Golgi trafficking are markedly compromised in patient cells. As a consequence, PARK20 fibroblasts accumulate large amounts of cargo proteins within the ER, leading to the induction of ER stress. Interestingly, this stressful state is coupled to the activation of the PERK/eIF2α/ATF4/CHOP pathway of the Unfolded Protein Response (UPR). In addition, PARK20 fibroblasts reveal upregulation of oxidative stress markers and total ROS production with concomitant alteration of the morphology of the mitochondrial network. Interestingly, treatment of PARK20 cells with GSK2606414 (GSK), a specific inhibitor of PERK activity, restores the level of ROS, signaling a direct correlation between ER stress and the induction of oxidative stress in the PARK20 cells. All together, these findings suggest that dysfunction of early secretory pathway might contribute to the pathogenesis of the disease.
Collapse
Affiliation(s)
- Giuseppina Amodio
- Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Salerno, Italy
| | - Ornella Moltedo
- Department of Pharmacy, University of Salerno, Salerno, Italy
| | - Dominga Fasano
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Lucrezia Zerillo
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Marco Oliveti
- Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Salerno, Italy
| | - Paola Di Pietro
- Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Salerno, Italy
| | - Raffaella Faraonio
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Paolo Barone
- Section of Neuroscience, Department of Medicine, Surgery and Dentistry, University of Salerno, Salerno, Italy
| | - Maria Teresa Pellecchia
- Section of Neuroscience, Department of Medicine, Surgery and Dentistry, University of Salerno, Salerno, Italy
| | - Anna De Rosa
- Department of Neuroscience, Reproductive, and Odontostomatological Sciences, University of Naples Federico II, Naples, Italy
| | - Giuseppe De Michele
- Department of Neuroscience, Reproductive, and Odontostomatological Sciences, University of Naples Federico II, Naples, Italy
| | | | | | | | - Lucio Nitsch
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Giovanna Maria Pierantoni
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Maurizio Renna
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Chiara Criscuolo
- Department of Neuroscience, Reproductive, and Odontostomatological Sciences, University of Naples Federico II, Naples, Italy
| | - Simona Paladino
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Paolo Remondelli
- Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Salerno, Italy
| |
Collapse
|
5
|
Shehata SN, Deak M, Collodet C, Spiegl SF, Geley S, Sumpton D, Sakamoto K. Identification of novel PCTAIRE-1/CDK16 substrates using a chemical genetic screen. Cell Signal 2019; 59:53-61. [PMID: 30880224 DOI: 10.1016/j.cellsig.2019.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 03/10/2019] [Accepted: 03/11/2019] [Indexed: 11/20/2022]
Abstract
PCTAIRE-1 (also known as cyclin-dependent protein kinase (CDK) 16), is a Ser/Thr kinase that has been implicated in many cellular processes, including cell cycle, spermatogenesis, neurite outgrowth, and vesicle trafficking. Most recently, it has been proposed as a novel X-linked intellectual disability (XLID) gene, where loss-of-function mutations have been identified in human patients. The precise molecular mechanisms that regulate PCTAIRE-1 remained largely obscure, and only a few cellular targets/substrates have been proposed with no clear functional significance. We and others recently showed that cyclin Y binds and activates PCTAIRE-1 via phosphorylation and 14-3-3 binding. In order to understand the physiological role that PCTAIRE-1 plays in brain, we have performed a chemical genetic screen in vitro using an engineered PCTAIRE-1/cyclin Y complex and mouse brain extracts. Our screen has identified potential PCTAIRE-1 substrates (AP2-Associated Kinase 1 (AAK1), dynamin 1, and synaptojanin 1) in brain that have been shown to regulate crucial steps of receptor endocytosis, and are involved in control of neuronal synaptic transmission. Furthermore, mass spectrometry and protein sequence analyses have identified potential PCTAIRE-1 regulated phosphorylation sites on AAK1 and we validated their PCTAIRE-1 dependence in a cellular study and/or brain tissue lysates. Our results shed light onto the missing link between PCTAIRE-1 regulation and proposed physiological functions, and provide a basis upon which to further study PCTAIRE-1 function in vivo and its potential role in neuronal/brain disorders.
Collapse
|
6
|
Hong D, Cong L, Zhong S, He Y, Xin L, Gao X, Zhang J. Clonazepam improves the symptoms of two siblings with novel variants in the SYNJ1 gene. Parkinsonism Relat Disord 2019; 62:221-5. [PMID: 30473187 DOI: 10.1016/j.parkreldis.2018.11.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/15/2018] [Accepted: 11/17/2018] [Indexed: 11/23/2022]
Abstract
BACKGROUND Mutations in the SYNJ1 gene have been associated with early-onset of atypical Parkinson's disease or severe neurodegeneration with intractable seizures. Due to the rarity of the disease, there were limitations in the quality of available treatment options for SYNJ1-related diseases. METHODS Two affected siblings from a non-consanguineous family were evaluated through a set of clinical and laboratory tests. The genetic screening was performed through exome next generation sequencing. SYNJ1 mutant transcripts were purified and cloned into the vectors for Sanger sequence of single-stranded DNA. Relative level of the SYNJ1 transcript was measured by quantitative PCR. RESULTS The clinical features were characterized by a triad of symptomatic progression including diplopia, dystonia, and Parkinsonism. The dystonic symptoms were outstanding in the siblings, which preceded the Parkinsonism symptoms and became the main symptoms. Clonazepam resolved the clinical symptoms, especially the severe trunk dystonia and dystonic postures of limbs. Compound heterozygous variants (c.2579-2A > G; p.A860Gfs*5 and c.3845C > A; p.P1282L) were identified in the SYNJ1 gene co-segregating in this family. The proline residue is highly conserved across species and predicted to be damaging by several in silico tools. The splice site variant caused a skip of exon 20 and a significant reduction of the SYNJ1 transcript expression. CONCLUSIONS Our study expanded the clinical and genetic spectrums of the SYNJ1-related diseases. Although our study was a preliminary observation, it indicated that clonazepam could improve the dystonic symptoms caused by mutations in the SYNJ1 gene.
Collapse
|
7
|
Chen KH, Wu RM, Lin HI, Tai CH, Lin CH. Mutational analysis of SYNJ1 gene (PARK20) in Parkinson's disease in a Taiwanese population. Neurobiol Aging 2015; 36:2905.e7-8. [PMID: 26149920 DOI: 10.1016/j.neurobiolaging.2015.06.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 06/05/2015] [Indexed: 02/03/2023]
Abstract
Whole-exome sequencing recently identified a homozygous truncating mutation in Synaptojanin 1 (SYNJ1, PARK20), p.Arg258Gln, in 2 independent families with autosomal recessive young-onset parkinsonism with seizures and cognitive decline. This mutation's role in typical Parkinson's disease (PD) is unclear. We sequenced all coding exons and exon-intron boundaries of SYNJ1 gene in a total of 700 participants: 250 early-onset PD patients, 100 familial PD patients with family history, and 350 age/sex-matched controls from Taiwan. No patients harbored homozygous or compound heterozygous mutations of SYNJ1 gene in our study population. We observed 1 novel missense substitution, p.Ala551Val, in a single heterozygous state in 1 early-onset PD patient. This variant was not observed in controls with total 700 normal alleles. The clinical phenotype of this genetic variant carrier is similar to that seen in idiopathic PD, with motor fluctuation after 11 years of PD diagnosis and comorbidity with dementia after 13 years of motor symptoms. Our results suggest that mutations in SYNJ1 gene do not play a major role in early-onset or familial PD in our population.
Collapse
Affiliation(s)
- Kai-Hsiang Chen
- Department of Neurology, National Taiwan University Hospital, Hsin-Chu Branch, Hsin-Chiu, Taiwan; Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ruey-Meei Wu
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hang-I Lin
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chun-Hwei Tai
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chin-Hsien Lin
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan.
| |
Collapse
|
8
|
Zhu L, Zhong M, Zhao J, Rhee H, Caesar I, Knight EM, Volpicelli-Daley L, Bustos V, Netzer W, Liu L, Lucast L, Ehrlich ME, Robakis NK, Gandy SE, Cai D. Reduction of synaptojanin 1 accelerates Aβ clearance and attenuates cognitive deterioration in an Alzheimer mouse model. J Biol Chem 2013; 288:32050-63. [PMID: 24052255 DOI: 10.1074/jbc.m113.504365] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recent studies link synaptojanin 1 (synj1), the main phosphoinositol (4,5)-biphosphate phosphatase (PI(4,5)P2-degrading enzyme) in the brain and synapses, to Alzheimer disease. Here we report a novel mechanism by which synj1 reversely regulates cellular clearance of amyloid-β (Aβ). Genetic down-regulation of synj1 reduces both extracellular and intracellular Aβ levels in N2a cells stably expressing the Swedish mutant of amyloid precursor protein (APP). Moreover, synj1 haploinsufficiency in an Alzheimer disease transgenic mouse model expressing the Swedish mutant APP and the presenilin-1 mutant ΔE9 reduces amyloid plaque load, as well as Aβ40 and Aβ42 levels in hippocampus of 9-month-old animals. Reduced expression of synj1 attenuates cognitive deficits in these transgenic mice. However, reduction of synj1 does not affect levels of full-length APP and the C-terminal fragment, suggesting that Aβ generation by β- and γ-secretase cleavage is not affected. Instead, synj1 knockdown increases Aβ uptake and cellular degradation through accelerated delivery to lysosomes. These effects are partially dependent upon elevated PI(4,5)P2 with synj1 down-regulation. In summary, our data suggest a novel mechanism by which reduction of a PI(4,5)P2-degrading enzyme, synj1, improves amyloid-induced neuropathology and behavior deficits through accelerating cellular Aβ clearance.
Collapse
Affiliation(s)
- Li Zhu
- From the Department of Neurology and the Alzheimer's Disease Research Center and
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|