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Ma L, Kasula RK, Ouyang Q, Schmidt M, Morrow EM. GGA1 interacts with the endosomal Na+/H+ exchanger NHE6 governing localization to the endosome compartment. J Biol Chem 2024; 300:107552. [PMID: 39002678 PMCID: PMC11375261 DOI: 10.1016/j.jbc.2024.107552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 06/20/2024] [Accepted: 06/27/2024] [Indexed: 07/15/2024] Open
Abstract
Mutations in the endosomal Na+/H+ exchanger 6 (NHE6) cause Christianson syndrome, an X-linked neurological disorder. NHE6 functions in regulation of endosome acidification and maturation in neurons. Using yeast two-hybrid screening with the NHE6 carboxyl terminus as bait, we identify Golgi-associated, gamma adaptin ear-containing, ADP-ribosylation factor (ARF) binding protein 1 (GGA1) as an interacting partner for NHE6. We corroborated the NHE6-GGA1 interaction using: coimmunoprecipitation; overexpressed constructs in mammalian cells; and coimmunoprecipitation of endogenously expressed GGA1 and NHE6 from neuroblastoma cells, as well as from the mouse brain. We demonstrate that GGA1 interacts with organellar NHEs (NHE6, NHE7, and NHE9) and that there is significantly less interaction with cell-surface localized NHEs (NHE1 and NHE5). By constructing hybrid NHE1/NHE6 exchangers, we demonstrate the cytoplasmic tail of NHE6 interacts most strongly with GGA1. We demonstrate the colocalization of NHE6 and GGA1 in cultured, primary hippocampal neurons, using super-resolution microscopy. We test the hypothesis that the interaction of NHE6 and GGA1 functions in the localization of NHE6 to the endosome compartment. Using subcellular fractionation experiments, we show that NHE6 is mislocalized in GGA1 KO cells, wherein we find less NHE6 in endosomes, but more NHE6 transport to lysosomes, and more Golgi retention of NHE6, with increased exocytosis to the surface plasma membrane. Consistent with NHE6 mislocalization, and Golgi retention, we find the intraluminal pH in Golgi to be alkalinized in GGA1-null cells. Our study demonstrates a new interaction between NHE6 and GGA1 which functions in the localization of this intracellular NHE to the endosome compartment.
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Affiliation(s)
- Li Ma
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA; Center for Translational Neuroscience, Brown University, Providence, Rhode Island, USA
| | - Ravi Kiran Kasula
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA; Center for Translational Neuroscience, Brown University, Providence, Rhode Island, USA
| | - Qing Ouyang
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA; Center for Translational Neuroscience, Brown University, Providence, Rhode Island, USA
| | - Michael Schmidt
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA; Center for Translational Neuroscience, Brown University, Providence, Rhode Island, USA
| | - Eric M Morrow
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA; Center for Translational Neuroscience, Brown University, Providence, Rhode Island, USA.
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He H, Zhang H, Chen H, He F, Yin F, Stauber T, Zou X, Peng J. Functional analysis of two SLC9A6 frameshift variants in lymphoblastoid cells from patients with Christianson syndrome. CNS Neurosci Ther 2023; 29:4059-4069. [PMID: 37381736 PMCID: PMC10651982 DOI: 10.1111/cns.14329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/30/2023] [Accepted: 06/17/2023] [Indexed: 06/30/2023] Open
Abstract
BACKGROUND Christianson syndrome (CS) is caused by mutations in SLC9A6 and is characterized by global developmental delay, epilepsy, hyperkinesis, ataxia, microcephaly, and behavioral disorder. However, the molecular mechanism by which these SLC9A6 mutations cause CS in humans is not entirely understood, and there is no objective method to determine the pathogenicity of single SLC9A6 variants. METHODS Trio-based whole exome sequencing (WES) was carried out on two individuals with suspicion of CS. qRT-PCR, western blot analysis, filipin staining, lysosomal enzymatic assays, and electron microscopy examination, using EBV-LCLs established from the two patients, were performed. RESULTS Trio-based WES identified a hemizygous SLC9A6 c.1560dupT, p.T521Yfs*23 variant in proband 1 and a hemizygous SLC9A6 c.608delA, p.H203Lfs*10 variant in proband 2. Both children exhibited typical phenotypes associated with CS. Expression analysis in EBV-LCLs derived from the two patients showed a significant decrease in mRNA levels and no detectable normal NHE6 protein. EBV-LCLs showed a statistically significant increase in unesterified cholesterol in patient 1, but only non-significant increase in patient 2 when stained with filipin. Activities of lysosomal enzymes (β-hexosaminidase A, β-hexosaminidase A + B, β-galactosidase, galactocerebrosidase, arylsulfatase A) of EBV-LCLs did not significantly differ between the two patients and six controls. Importantly, by electron microscopy we detected an accumulation of lamellated membrane structures, deformed mitochondria, and lipid droplets in the patients' EBV-LCLs. CONCLUSIONS The SLC9A6 p.T521Yfs*23 and p.H203Lfs*10 variants in our patients result in loss of NHE6. Alterations of mitochondria and lipid metabolism may play a role in the pathogenesis of CS. Moreover, the combination of filipin staining with electron microscopy examination of patient lymphoblastoid cells can serve as a useful complementary diagnostic method for CS.
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Affiliation(s)
- Hailan He
- Department of Pediatrics, Xiangya HospitalCentral South UniversityChangshaChina
- Hunan Intellectual and Developmental Disabilities Research CenterChangshaChina
| | - Huiwen Zhang
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, Shanghai Institute for Pediatric ResearchShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Hui Chen
- Department of NeurologyJiangxi Provincial Children's HospitalNanchangChina
| | - Fang He
- Department of Pediatrics, Xiangya HospitalCentral South UniversityChangshaChina
- Hunan Intellectual and Developmental Disabilities Research CenterChangshaChina
| | - Fei Yin
- Department of Pediatrics, Xiangya HospitalCentral South UniversityChangshaChina
- Hunan Intellectual and Developmental Disabilities Research CenterChangshaChina
| | - Tobias Stauber
- Department of Human Medicine and Institute for Molecular MedicineMSH Medical School HamburgHamburgGermany
| | - Xiaomin Zou
- Department of Pediatrics, Xiangya HospitalCentral South UniversityChangshaChina
- Hunan Intellectual and Developmental Disabilities Research CenterChangshaChina
| | - Jing Peng
- Department of Pediatrics, Xiangya HospitalCentral South UniversityChangshaChina
- Hunan Intellectual and Developmental Disabilities Research CenterChangshaChina
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Ma L, Kasula RK, Ouyang Q, Schmidt M, Morrow EM. GGA1 interacts with the endosomal Na+/H+ Exchanger NHE6 governing localization to the endosome compartment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.08.565997. [PMID: 37986849 PMCID: PMC10659387 DOI: 10.1101/2023.11.08.565997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Mutations in the endosomal Na+/H+ exchanger (NHE6) cause Christianson syndrome (CS), an X-linked neurological disorder. Previous studies have shown that NHE6 functions in regulation of endosome acidification and maturation in neurons. Using yeast two-hybrid screening with the NHE6 carboxyl-terminus as bait, we identify Golgi-associated, Gamma adaptin ear containing, ARF binding protein 1 (GGA1) as an interacting partner for NHE6. We corroborated the NHE6-GGA1 interaction using co-immunoprecipitation (co-IP): using over-expressed constructs in mammalian cells; and co-IP of endogenously-expressed GGA1 and NHE6 from neuroblastoma cells, as well as from mouse brain. We demonstrate that GGA1 interacts with organellar NHEs (NHE6, NHE7 and NHE9) but not with cell-surface localized NHEs (NHE1 and NHE5). By constructing hybrid NHE1/NHE6 exchangers, we demonstrate that the cytoplasmic tail of NHE6 is necessary and sufficient for interactions with GGA1. We demonstrate the co-localization of NHE6 and GGA1 in cultured, primary hippocampal neurons, using super-resolution microscopy. We test the hypothesis that the interaction of NHE6 and GGA1 functions in the localization of NHE6 to the endosome compartment. Using subcellular fractionation experiments, we show that NHE6 is mis-localized in GGA1 knockout cells wherein we find less NHE6 in endosomes but more NHE6 transport to lysosomes, and more Golgi retention of NHE6 with increased exocytosis to the surface plasma membrane. Consistent with NHE6 mis-localization, and Golgi retention, we find the intra-luminal pH in Golgi to be alkalinized. Our study demonstrates a new interaction between NHE6 and GGA1 which functions in the localization of this intra-cellular NHE to the endosome compartment.
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4
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Figueroa KP, Anderson CJ, Paul S, Dansithong W, Gandelman M, Scoles DR, Pulst SM. Slc9a6 mutation causes Purkinje cell loss and ataxia in the shaker rat. Hum Mol Genet 2023; 32:1647-1659. [PMID: 36621975 PMCID: PMC10162436 DOI: 10.1093/hmg/ddad004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 12/29/2022] [Accepted: 01/05/2023] [Indexed: 01/10/2023] Open
Abstract
The shaker rat carries a naturally occurring mutation leading to progressive ataxia characterized by Purkinje cell (PC) loss. We previously reported on fine-mapping the shaker locus to the long arm of the rat X chromosome. In this work, we sought to identify the mutated gene underlying the shaker phenotype and confirm its identity by functional complementation. We fine-mapped the candidate region and analyzed cerebellar transcriptomes, identifying a XM_217630.9 (Slc9a6):c.[191_195delinsA] variant in the Slc9a6 gene that segregated with disease. We generated an adeno-associated virus (AAV) targeting Slc9a6 expression to PCs using the mouse L7-6 (L7) promoter. We administered the AAV prior to the onset of PC degeneration through intracerebroventricular injection and found that it reduced the shaker motor, molecular and cellular phenotypes. Therefore, Slc9a6 is mutated in shaker and AAV-based gene therapy may be a viable therapeutic strategy for Christianson syndrome, also caused by Slc9a6 mutation.
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Affiliation(s)
- Karla P Figueroa
- Department of Neurology, University of Utah, Salt Lake City, UT 84132, USA
| | - Collin J Anderson
- Department of Neurology, University of Utah, Salt Lake City, UT 84132, USA
- School of Medical Sciences, University of Sydney, Camperdown NSW 2006, Australia
- School of Biomedical Engineering University of Sydney, Darlington NSW 2008, Australia
| | - Sharan Paul
- Department of Neurology, University of Utah, Salt Lake City, UT 84132, USA
| | - Warunee Dansithong
- Department of Neurology, University of Utah, Salt Lake City, UT 84132, USA
| | - Mandi Gandelman
- Department of Neurology, University of Utah, Salt Lake City, UT 84132, USA
| | - Daniel R Scoles
- Department of Neurology, University of Utah, Salt Lake City, UT 84132, USA
| | - Stefan M Pulst
- Department of Neurology, University of Utah, Salt Lake City, UT 84132, USA
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5
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Chen L, Chen L, Li X, Qin L, Zhu Y, Zhang Q, Tan D, He Y, Wang YH. Transcriptomic profiling of hepatic tissues for drug metabolism genes in nonalcoholic fatty liver disease: A study of human and animals. Front Endocrinol (Lausanne) 2023; 13:1034494. [PMID: 36686439 PMCID: PMC9845619 DOI: 10.3389/fendo.2022.1034494] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 12/08/2022] [Indexed: 01/05/2023] Open
Abstract
Background Drug metabolism genes are involved in the in vivo metabolic processing of drugs. In previous research, we found that a high-fat diet affected the transcript levels of mouse hepatic genes responsible for drug metabolism. Aims Our research intends to discover the drug metabolism genes that are dysregulated at the transcriptome level in nonalcoholic fatty liver disease (NAFLD). Methods We analyzed the transcriptome for drug metabolism genes of 35 human liver tissues obtained during laparoscopic cholecystectomy. Additionally, we imported transcriptome data from mice fed a high-fat diet in previous research and two open-access Gene Expression Omnibus (GEO) datasets (GSE63067 and GSE89632). Then, using quantitative real-time polymerase chain reaction (qRT-PCR), we cross-linked the differentially expressed genes (DEGs) in clinical and animal samples and validated the common genes. Results In this study, we identified 35 DEGs, of which 33 were up-regulated and two were down-regulated. Moreover, we found 71 DEGs (39 up- and 32 down-regulated), 276 DEGs (157 up- and 119 down-regulated), and 158 DEGs (117 up- and 41 down-regulated) in the GSE63067, GSE89632, and high-fat diet mice, respectively. Of the 35 DEGs, nine co-regulated DEGs were found in the Venn diagram (CYP20A1, CYP2U1, SLC9A6, SLC26A6, SLC31A1, SLC46A1, SLC46A3, SULT1B1, and UGT2A3). Conclusion Nine significant drug metabolism genes were identified in NAFLD. Future research should investigate the impacts of these genes on drug dose adjustment in patients with NAFLD. Clinical Trial Registration http://www.chictr.org.cn, identifier ChiCTR2100041714.
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Affiliation(s)
- Li Chen
- Department of Pharmacy, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- The Key Laboratory of the Ministry of Education of the Basic Pharmacology, School of Pharmacy, Zunyi Medical University, Zunyi, China
- The Joint International Research Laboratory of Ethnomedicine of the Ministry of Education, School of Pharmacy, Zunyi Medical University, Zunyi, China
| | - Lu Chen
- The Key Laboratory of the Ministry of Education of the Basic Pharmacology, School of Pharmacy, Zunyi Medical University, Zunyi, China
- The Joint International Research Laboratory of Ethnomedicine of the Ministry of Education, School of Pharmacy, Zunyi Medical University, Zunyi, China
| | - Xu Li
- The Key Laboratory of the Ministry of Education of the Basic Pharmacology, School of Pharmacy, Zunyi Medical University, Zunyi, China
- The Joint International Research Laboratory of Ethnomedicine of the Ministry of Education, School of Pharmacy, Zunyi Medical University, Zunyi, China
| | - Lin Qin
- The Key Laboratory of the Ministry of Education of the Basic Pharmacology, School of Pharmacy, Zunyi Medical University, Zunyi, China
- The Joint International Research Laboratory of Ethnomedicine of the Ministry of Education, School of Pharmacy, Zunyi Medical University, Zunyi, China
| | - Yan Zhu
- Department of Pharmacy, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Qianru Zhang
- The Key Laboratory of the Ministry of Education of the Basic Pharmacology, School of Pharmacy, Zunyi Medical University, Zunyi, China
- The Joint International Research Laboratory of Ethnomedicine of the Ministry of Education, School of Pharmacy, Zunyi Medical University, Zunyi, China
| | - Daopeng Tan
- The Key Laboratory of the Ministry of Education of the Basic Pharmacology, School of Pharmacy, Zunyi Medical University, Zunyi, China
- The Joint International Research Laboratory of Ethnomedicine of the Ministry of Education, School of Pharmacy, Zunyi Medical University, Zunyi, China
| | - Yuqi He
- The Key Laboratory of the Ministry of Education of the Basic Pharmacology, School of Pharmacy, Zunyi Medical University, Zunyi, China
- The Joint International Research Laboratory of Ethnomedicine of the Ministry of Education, School of Pharmacy, Zunyi Medical University, Zunyi, China
| | - Yu-He Wang
- Department of Pharmacy, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- The Key Laboratory of the Ministry of Education of the Basic Pharmacology, School of Pharmacy, Zunyi Medical University, Zunyi, China
- The Joint International Research Laboratory of Ethnomedicine of the Ministry of Education, School of Pharmacy, Zunyi Medical University, Zunyi, China
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6
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Gao AYL, Lourdin-De Filippis E, Orlowski J, McKinney RA. Roles of Endomembrane Alkali Cation/Proton Exchangers in Synaptic Function and Neurodevelopmental Disorders. Front Physiol 2022; 13:892196. [PMID: 35547574 PMCID: PMC9081726 DOI: 10.3389/fphys.2022.892196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 03/30/2022] [Indexed: 12/25/2022] Open
Abstract
Endomembrane alkali cation (Na+, K+)/proton (H+) exchangers (eNHEs) are increasingly associated with neurological disorders. These eNHEs play integral roles in regulating the luminal pH, processing, and trafficking of cargo along the secretory (Golgi and post-Golgi vesicles) and endocytic (early, recycling, and late endosomes) pathways, essential regulatory processes vital for neuronal development and plasticity. Given the complex morphology and compartmentalization of multipolar neurons, the contribution of eNHEs in maintaining optimal pH homeostasis and cargo trafficking is especially significant during periods of structural and functional development and remodeling. While the importance of eNHEs has been demonstrated in a variety of non-neuronal cell types, their involvement in neuronal function is less well understood. In this review, we will discuss their emerging roles in excitatory synaptic function, particularly as it pertains to cellular learning and remodeling. We will also explore their connections to neurodevelopmental conditions, including intellectual disability, autism, and attention deficit hyperactivity disorders.
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Affiliation(s)
- Andy Y L Gao
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada.,Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, Canada
| | | | - John Orlowski
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - R Anne McKinney
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, Canada
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7
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Liu X, Xie L, Fang Z, Jiang L. Case Report: Novel SLC9A6 Splicing Variant in a Chinese Boy With Christianson Syndrome With Electrical Status Epilepticus During Sleep. Front Neurol 2022; 12:796283. [PMID: 35095740 PMCID: PMC8795361 DOI: 10.3389/fneur.2021.796283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 12/17/2021] [Indexed: 12/30/2022] Open
Abstract
We investigated the existence and potential pathogenicity of a SLC9A6 splicing variant in a Chinese boy with Christianson Syndrome (CS), which was reported for the first time in China. Trio whole-exome sequencing (WES) was performed in the proband and his parents. Multiple computer prediction tools were used to evaluate the pathogenicity of the variant, and reverse transcription-polymerase chain reaction (RT-PCR) analysis and cDNA sequencing were performed to verify the RNA splicing results. The patient presented with characteristic features of CS: global developmental delay, seizures, absent speech, truncal ataxia, microcephaly, ophthalmoplegia, smiling face and hyperkinesis with electrical status epilepticus during sleep (ESES) detected in an electroencephalogram (EEG). A SLC9A6 splicing variant was identified by WES and complete skipping of exon 10 was confirmed by RT-PCR. This resulted in altered gene function and was predicted to be pathogenic. ESES observed early in the disease course is considered to be a significant feature of CS with the SLC9A6 variant. Combined genetic analysis at both the DNA and RNA levels is necessary to confirm the pathogenicity of this variant and its role in the clinical diagnosis of CS.
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8
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Plooster M, Rossi G, Farrell MS, McAfee JC, Bell JL, Ye M, Diering GH, Won H, Gupton SL, Brennwald P. Schizophrenia-Linked Protein tSNARE1 Regulates Endosomal Trafficking in Cortical Neurons. J Neurosci 2021; 41:9466-9481. [PMID: 34642214 PMCID: PMC8580139 DOI: 10.1523/jneurosci.0556-21.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 10/04/2021] [Accepted: 10/04/2021] [Indexed: 12/13/2022] Open
Abstract
TSNARE1, which encodes the protein tSNARE1, is a high-confidence gene candidate for schizophrenia risk, but nothing is known about its cellular or physiological function. We identified the major gene products of TSNARE1 and their cytoplasmic localization and function in endosomal trafficking in cortical neurons. We validated three primary isoforms of TSNARE1 expressed in human brain, all of which encode a syntaxin-like Qa SNARE domain. RNA-sequencing data from adult and fetal human brain suggested that the majority of tSNARE1 lacks a transmembrane domain that is thought to be necessary for membrane fusion. Biochemical data demonstrate that tSNARE1 can compete with Stx12 for incorporation into an endosomal SNARE complex, supporting its possible role as an inhibitory SNARE. Live-cell imaging in cortical neurons from mice of both sexes demonstrated that brain tSNARE1 isoforms localized to the endosomal network. The most abundant brain isoform, tSNARE1c, localized most frequently to Rab7+ late endosomes, and endogenous tSNARE1 displayed a similar localization in human neural progenitor cells and neuroblastoma cells. In mature rat neurons from both sexes, tSNARE1 localized to the dendritic shaft and dendritic spines, supporting a role for tSNARE1 at the postsynapse. Expression of either tSNARE1b or tSNARE1c, which differ only in their inclusion or exclusion of an Myb-like domain, delayed the trafficking of the dendritic endosomal cargo Nsg1 into late endosomal and lysosomal compartments. These data suggest that tSNARE1 regulates endosomal trafficking in cortical neurons, likely by negatively regulating early endosomal to late endosomal trafficking.SIGNIFICANCE STATEMENT Schizophrenia is a severe and polygenic neuropsychiatric disorder. Understanding the functions of high-confidence candidate genes is critical toward understanding how their dysfunction contributes to schizophrenia pathogenesis. TSNARE1 is one of the high-confidence candidate genes for schizophrenia risk, yet nothing was known about its cellular or physiological function. Here we describe the major isoforms of TSNARE1 and their cytoplasmic localization and function in the endosomal network in cortical neurons. Our results are consistent with the hypothesis that the majority of brain tSNARE1 acts as a negative regulator to endolysosomal trafficking.
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Affiliation(s)
- Melissa Plooster
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Guendalina Rossi
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Martilias S Farrell
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Jessica C McAfee
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599
- UNC Neuroscience Center, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Jessica L Bell
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599
- UNC Neuroscience Center, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Michael Ye
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Graham H Diering
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina 27599
- UNC Neuroscience Center, University of North Carolina, Chapel Hill, North Carolina 27599
- Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Hyejung Won
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599
- UNC Neuroscience Center, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Stephanie L Gupton
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina 27599
- UNC Neuroscience Center, University of North Carolina, Chapel Hill, North Carolina 27599
- Lineberger Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Patrick Brennwald
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina 27599
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9
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Pohlkamp T, Xian X, Wong CH, Durakoglugil MS, Werthmann GC, Saido TC, Evers BM, White CL, Connor J, Hammer RE, Herz J. NHE6 depletion corrects ApoE4-mediated synaptic impairments and reduces amyloid plaque load. eLife 2021; 10:72034. [PMID: 34617884 PMCID: PMC8547963 DOI: 10.7554/elife.72034] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 09/19/2021] [Indexed: 11/13/2022] Open
Abstract
Apolipoprotein E4 (ApoE4) is the most important and prevalent risk factor for late-onset Alzheimer’s disease (AD). The isoelectric point of ApoE4 matches the pH of the early endosome (EE), causing its delayed dissociation from ApoE receptors and hence impaired endolysosomal trafficking, disruption of synaptic homeostasis, and reduced amyloid clearance. We have shown that enhancing endosomal acidification by inhibiting the EE-specific sodium-hydrogen exchanger 6 (NHE6) restores vesicular trafficking and normalizes synaptic homeostasis. Remarkably and unexpectedly, loss of NHE6 (encoded by the gene Slc9a6) in mice effectively suppressed amyloid deposition even in the absence of ApoE4, suggesting that accelerated acidification of EEs caused by the absence of NHE6 occludes the effect of ApoE on amyloid plaque formation. NHE6 suppression or inhibition may thus be a universal, ApoE-independent approach to prevent amyloid buildup in the brain. These findings suggest a novel therapeutic approach for the prevention of AD by which partial NHE6 inhibition reverses the ApoE4-induced endolysosomal trafficking defect and reduces plaque load.
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Affiliation(s)
- Theresa Pohlkamp
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States.,Center for Translational Neurodegeneration Research, Dallas, United States
| | - Xunde Xian
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States.,Center for Translational Neurodegeneration Research, Dallas, United States.,Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University, Beijing, China
| | - Connie H Wong
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States.,Center for Translational Neurodegeneration Research, Dallas, United States
| | - Murat S Durakoglugil
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States.,Center for Translational Neurodegeneration Research, Dallas, United States
| | - Gordon Chandler Werthmann
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States.,Center for Translational Neurodegeneration Research, Dallas, United States
| | - Takaomi C Saido
- Laboratory for Proteolytic Neuroscience, Riken Center for Brain Science, Wako, Japan
| | - Bret M Evers
- Center for Translational Neurodegeneration Research, Dallas, United States
| | - Charles L White
- Pathology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Jade Connor
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States.,Center for Translational Neurodegeneration Research, Dallas, United States
| | - Robert E Hammer
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, United States
| | - Joachim Herz
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States.,Center for Translational Neurodegeneration Research, Dallas, United States.,Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, United States.,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, United States
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10
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Pizzagalli MD, Bensimon A, Superti‐Furga G. A guide to plasma membrane solute carrier proteins. FEBS J 2021; 288:2784-2835. [PMID: 32810346 PMCID: PMC8246967 DOI: 10.1111/febs.15531] [Citation(s) in RCA: 186] [Impact Index Per Article: 62.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 08/07/2020] [Accepted: 08/17/2020] [Indexed: 12/13/2022]
Abstract
This review aims to serve as an introduction to the solute carrier proteins (SLC) superfamily of transporter proteins and their roles in human cells. The SLC superfamily currently includes 458 transport proteins in 65 families that carry a wide variety of substances across cellular membranes. While members of this superfamily are found throughout cellular organelles, this review focuses on transporters expressed at the plasma membrane. At the cell surface, SLC proteins may be viewed as gatekeepers of the cellular milieu, dynamically responding to different metabolic states. With altered metabolism being one of the hallmarks of cancer, we also briefly review the roles that surface SLC proteins play in the development and progression of cancer through their influence on regulating metabolism and environmental conditions.
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Affiliation(s)
- Mattia D. Pizzagalli
- CeMM, Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Ariel Bensimon
- CeMM, Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Giulio Superti‐Furga
- CeMM, Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
- Center for Physiology and PharmacologyMedical University of ViennaAustria
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Gozes I, Nalivaeva NN, Hirrlinger J, Blumrich EM, Turner AJ. Molecular Mechanisms of Cognitive Impairment and Intellectual Disability-Virtual ESN Mini-Conference in Conjunction with the FENS Forum, July 11-15, 2020. J Mol Neurosci 2020; 70:1927-1933. [PMID: 33089437 DOI: 10.1007/s12031-020-01718-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Illana Gozes
- Elton Laboratory for Molecular Neuroendocrinology, Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Sagol School of Neuroscience and Adams Super Center for Brain Studies, Tel Aviv University, 69978, Tel Aviv, Israel.
| | - Natalia N Nalivaeva
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany.,Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Eva-Maria Blumrich
- Centre for Brain Discovery Sciences, School for Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Anthony J Turner
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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Hayashi H, Wang T, Tanaka M, Ogiwara S, Okada C, Ito M, Fukunishi N, Iida Y, Nakamura A, Sasaki A, Amano S, Yoshida K, Otomo A, Ohtsuka M, Hadano S. Monitoring the autophagy-endolysosomal system using monomeric Keima-fused MAP1LC3B. PLoS One 2020; 15:e0234180. [PMID: 32511278 PMCID: PMC7279612 DOI: 10.1371/journal.pone.0234180] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 05/20/2020] [Indexed: 12/20/2022] Open
Abstract
The autophagy-endolysosomal pathway is an evolutionally conserved degradation system that is tightly linked to a wide variety of physiological processes. Dysfunction of this system is associated with many pathological conditions such as cancer, inflammation and neurodegenerative diseases. Therefore, monitoring the cellular autophagy-endolysosomal activity is crucial for studies on the pathogenesis as well as therapeutics of such disorders. To this end, we here sought to create a novel means exploiting Keima, an acid-stable fluorescent protein possessing pH-dependent fluorescence excitation spectra, for precisely monitoring the autophagy-endolysosomal system. First, we generated three lines of transgenic (tg) mouse expressing monomeric Keima-fused MAP1LC3B (mKeima-LC3B). Then, these tg mice were subjected to starvation by food-restriction, and also challenged to neurodegeneration by genetically crossing with a mouse model of amyotrophic lateral sclerosis; i.e., SOD1H46R transgenic mouse. Unexpectedly, despite that a lipidated-form of endogenous LC3 (LC3-II) was significantly increased, those of mKeima-LC3B (mKeima-LC3B-II) were not changed under both stressed conditions. It was also noted that mKeima-LC3B-positive aggregates were progressively accumulated in the spinal cord of SOD1H46R;mKeima-LC3B double-tg mice, suggestive of acid-resistance and aggregate-prone natures of long-term overexpressed mKeima-LC3B in vivo. Next, we characterized mouse embryonic fibroblasts (MEFs) derived from mKeima-LC3B-tg mice. In contrast with in vivo, levels of mKeima-LC3B-I were decreased under starved conditions. Furthermore, when starved MEFs were treated with chloroquine (CQ), the abundance of mKeima-LC3B-II was significantly increased. Remarkably, when cultured medium was repeatedly changed between DMEM (nutrient-rich) and EBSS (starvation), acidic/neutral signal ratios of mKeima-LC3B-positive compartments were rapidly and reversibly shifted, which were suppressed by the CQ treatment, indicating that intraluminal pH of mKeima-LC3B-positive vesicles was changeable upon nutritional conditions of culture media. Taken together, although mKeima-LC3B-tg mice may not be an appropriate tool to monitor the autophagy-endolysosomal system in vivo, mKeima-LC3B must be one of the most sensitive reporter molecules for monitoring this system under in vitro cultured conditions.
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Affiliation(s)
- Hideki Hayashi
- Support Center for Medical Research and Education, Isehara Research Promotion Division, Tokai University, Isehara, Kanagawa, Japan
| | - Ting Wang
- Support Center for Medical Research and Education, Isehara Research Promotion Division, Tokai University, Isehara, Kanagawa, Japan
| | - Masayuki Tanaka
- Support Center for Medical Research and Education, Isehara Research Promotion Division, Tokai University, Isehara, Kanagawa, Japan
| | - Sanae Ogiwara
- Support Center for Medical Research and Education, Isehara Research Promotion Division, Tokai University, Isehara, Kanagawa, Japan
| | - Chisa Okada
- Support Center for Medical Research and Education, Isehara Research Promotion Division, Tokai University, Isehara, Kanagawa, Japan
| | - Masatoshi Ito
- Support Center for Medical Research and Education, Isehara Research Promotion Division, Tokai University, Isehara, Kanagawa, Japan
| | - Nahoko Fukunishi
- Support Center for Medical Research and Education, Isehara Research Promotion Division, Tokai University, Isehara, Kanagawa, Japan
| | - Yumi Iida
- Support Center for Medical Research and Education, Isehara Research Promotion Division, Tokai University, Isehara, Kanagawa, Japan
| | - Ayaka Nakamura
- Support Center for Medical Research and Education, Isehara Research Promotion Division, Tokai University, Isehara, Kanagawa, Japan
| | - Ayumi Sasaki
- Support Center for Medical Research and Education, Isehara Research Promotion Division, Tokai University, Isehara, Kanagawa, Japan
| | - Shunji Amano
- Support Center for Medical Research and Education, Isehara Research Promotion Division, Tokai University, Isehara, Kanagawa, Japan
| | - Kazuhiro Yoshida
- Support Center for Medical Research and Education, Isehara Research Promotion Division, Tokai University, Isehara, Kanagawa, Japan
| | - Asako Otomo
- Molecular Neuropathobiology Laboratory, Department of Molecular Life Sciences, Tokai University School of Medicine, Isehara, Kanagawa, Japan
- The Institute of Medical Sciences, Tokai University, Isehara, Kanagawa, Japan
- Micro/Nano Technology Center, Tokai University, Hiratsuka, Kanagawa, Japan
| | - Masato Ohtsuka
- Genetic Engineering and Genome Editing Laboratory, Department of Molecular Life Sciences, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Shinji Hadano
- Molecular Neuropathobiology Laboratory, Department of Molecular Life Sciences, Tokai University School of Medicine, Isehara, Kanagawa, Japan
- The Institute of Medical Sciences, Tokai University, Isehara, Kanagawa, Japan
- Micro/Nano Technology Center, Tokai University, Hiratsuka, Kanagawa, Japan
- Research Center for Brain and Nervous Diseases, Tokai University Graduate School of Medicine, Isehara, Kanagawa, Japan
- * E-mail:
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