1
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Birnbaum R, Ezer S, Lotan NS, Eilat A, Sternlicht K, Benyamini L, Reish O, Falik-Zaccai T, Ben-Gad G, Rod R, Segel R, Kim K, Burton B, Keegan CE, Wagner M, Henderson LB, Mor N, Barel O, Hirsch Y, Meiner V, Elpeleg O, Harel T, Mor-Shakad H. Intellectual disability syndrome associated with a homozygous founder variant in SGSM3 in Ashkenazi Jews. J Med Genet 2024; 61:289-293. [PMID: 37833060 DOI: 10.1136/jmg-2023-109504] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 09/25/2023] [Indexed: 10/15/2023]
Abstract
BACKGROUND Neurodevelopmental disorders (NDDs) impact both the development and functioning of the brain and exhibit clinical and genetic variability. RAP and RAB proteins, belonging to the RAS superfamily, are identified as established contributors to NDDs. However, the involvement of SGSM (small G protein signalling modulator), another member of the RAS family, in NDDs has not been previously documented. METHODS Proband-only or trio exome sequencing was performed on DNA samples obtained from affected individuals and available family members. The variant prioritisation process focused on identifying rare deleterious variants. International collaboration aided in the identification of additional affected individuals. RESULTS We identified 13 patients from 8 families of Ashkenazi Jewish origin who all carried the same homozygous frameshift variant in SGSM3 gene. The variant was predicted to cause a loss of function, potentially leading to impaired protein structure or function. The variant co-segregated with the disease in all available family members. The affected individuals displayed mild global developmental delay and mild to moderate intellectual disability. Additional prevalent phenotypes observed included hypotonia, behavioural challenges and short stature. CONCLUSIONS An Ashkenazi Jewish homozygous founder variant in SGSM3 was discovered in individuals with NDDs and short stature. This finding establishes a connection between another member of the RAS family and NDDs. Additional research is needed to uncover the specific molecular mechanisms by which SGSM3 influences neurodevelopmental processes and the regulation of growth.
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Affiliation(s)
- Rivka Birnbaum
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel
| | - Shlomit Ezer
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nava Shaul Lotan
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel
| | - Avital Eilat
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel
| | | | | | - Orit Reish
- Genetics Institute, Shamir Medical Center, Tzrifin, Israel
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Tzipora Falik-Zaccai
- Institute of Human Genetics, Western Galilee Hospital-Nahariya, Nahariya, Israel
| | - Gali Ben-Gad
- Department of Child Development, Galilee Medical Center, Nahariya, Israel
| | - Raya Rod
- The Center for Child Development and Pediatric Neurology, Western Galilee Hospital-Naharyia, Nahariya, Israel
| | | | - Katherine Kim
- Genetics, Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
- Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Barabra Burton
- Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
| | - Catherine E Keegan
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan, USA
| | - Mallory Wagner
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Nofar Mor
- The Genomic Unit, Sheba Cancer Research Center, Sheba Medical Center, Tel Hashomer, Israel
| | - Ortal Barel
- The Genomic Unit, Sheba Cancer Research Center, Sheba Medical Center, Tel Hashomer, Israel
| | - Yoel Hirsch
- Research, Dor Yeshroim, Brooklyn, New York, USA
- Dor Yeshorim, New York, New York, USA
| | - Vardiella Meiner
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Genetics, Hadassah Medical Center, Jerusalem, Jerusalem, Israel
| | - Orly Elpeleg
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Genetics, Hadassah Medical Center, Jerusalem, Jerusalem, Israel
| | - Tamar Harel
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Genetics, Hadassah Medical Center, Jerusalem, Jerusalem, Israel
| | - Hagar Mor-Shakad
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
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2
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Li J, Jaiswal MK, Chien JF, Kozlenkov A, Jung J, Zhou P, Gardashli M, Pregent LJ, Engelberg-Cook E, Dickson DW, Belzil VV, Mukamel EA, Dracheva S. Divergent single cell transcriptome and epigenome alterations in ALS and FTD patients with C9orf72 mutation. Nat Commun 2023; 14:5714. [PMID: 37714849 PMCID: PMC10504300 DOI: 10.1038/s41467-023-41033-y] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 08/21/2023] [Indexed: 09/17/2023] Open
Abstract
A repeat expansion in the C9orf72 (C9) gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Here we investigate single nucleus transcriptomics (snRNA-seq) and epigenomics (snATAC-seq) in postmortem motor and frontal cortices from C9-ALS, C9-FTD, and control donors. C9-ALS donors present pervasive alterations of gene expression with concordant changes in chromatin accessibility and histone modifications. The greatest alterations occur in upper and deep layer excitatory neurons, as well as in astrocytes. In neurons, the changes imply an increase in proteostasis, metabolism, and protein expression pathways, alongside a decrease in neuronal function. In astrocytes, the alterations suggest activation and structural remodeling. Conversely, C9-FTD donors have fewer high-quality neuronal nuclei in the frontal cortex and numerous gene expression changes in glial cells. These findings highlight a context-dependent molecular disruption in C9-ALS and C9-FTD, indicating unique effects across cell types, brain regions, and diseases.
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Affiliation(s)
- Junhao Li
- Department of Cognitive Science, University of California San Diego, La Jolla, CA, 92037, US
| | - Manoj K Jaiswal
- Friedman Brain Institute and Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, US
| | - Jo-Fan Chien
- Department of Physics, University of California San Diego, La Jolla, CA, 92037, US
| | - Alexey Kozlenkov
- Friedman Brain Institute and Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, US
| | - Jinyoung Jung
- Friedman Brain Institute and Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, US
| | - Ping Zhou
- Friedman Brain Institute and Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, US
| | | | - Luc J Pregent
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, US
| | | | - Dennis W Dickson
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, US
| | | | - Eran A Mukamel
- Department of Cognitive Science, University of California San Diego, La Jolla, CA, 92037, US.
| | - Stella Dracheva
- Friedman Brain Institute and Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, US.
- Research & Development and VISN2 MIREC, James J, Peters VA Medical Center, Bronx, NY, 10468, US.
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3
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Liu Y, Xu G, Fu H, Li P, Li D, Deng K, Gao W, Shang Y, Wu M. Membrane-bound transcription factor LRRC4 inhibits glioblastoma cell motility. Int J Biol Macromol 2023; 246:125590. [PMID: 37385320 DOI: 10.1016/j.ijbiomac.2023.125590] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 06/13/2023] [Accepted: 06/25/2023] [Indexed: 07/01/2023]
Abstract
Membrane-bound transcription factors (MTFs) have been observed in many types of organisms, such as plants, animals and microorganisms. However, the routes of MTF nuclear translocation are not well understood. Here, we reported that LRRC4 is a novel MTF that translocates to the nucleus as a full-length protein via endoplasmic reticulum-Golgi transport, which is different from the previously described nuclear entry mechanism. A ChIP-seq assay showed that LRRC4 target genes were mainly involved in cell motility. We confirmed that LRRC4 bound to the enhancer element of the RAP1GAP gene to activate its transcription and inhibited glioblastoma cell movement by affecting cell contraction and polarization. Furthermore, atomic force microscopy (AFM) confirmed that LRRC4 or RAP1GAP altered cellular biophysical properties, such as the surface morphology, adhesion force and cell stiffness. Thus, we propose that LRRC4 is an MTF with a novel route of nuclear translocation. Our observations demonstrate that LRRC4-null glioblastoma led to disordered RAP1GAP gene expression, which increased cellular movement. Re-expression of LRRC4 enabled it to suppress tumors, and this is a potential for targeted treatment in glioblastoma.
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Affiliation(s)
- Yang Liu
- Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China; NHC Key Laboratory of Carcinogenesis, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan 410008, China
| | - Gang Xu
- Diagnostics Department, Hengyang Medical College, University of South China, Hengyang, Hunan 421001, China
| | - Haijuan Fu
- Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China; NHC Key Laboratory of Carcinogenesis, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan 410008, China
| | - Peiyao Li
- NHC Key Laboratory of Carcinogenesis, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan 410008, China
| | - Danyang Li
- Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China; NHC Key Laboratory of Carcinogenesis, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan 410008, China
| | - Kun Deng
- Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China; NHC Key Laboratory of Carcinogenesis, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan 410008, China
| | - Wei Gao
- Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China; NHC Key Laboratory of Carcinogenesis, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan 410008, China
| | - Yujie Shang
- Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China; NHC Key Laboratory of Carcinogenesis, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan 410008, China
| | - Minghua Wu
- Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China; NHC Key Laboratory of Carcinogenesis, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Cancer Research Institute, Central South University, Changsha, Hunan 410008, China.
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4
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Zhang L, Liu C, Li Y, Wu Y, Wei Y, Zeng D, He S, Huang J, Li H. Plasma biomarker panel for major depressive disorder by quantitative proteomics using ensemble learning algorithm: A preliminary study. Psychiatry Res 2023; 323:115185. [PMID: 37003170 DOI: 10.1016/j.psychres.2023.115185] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 03/21/2023] [Accepted: 03/26/2023] [Indexed: 04/03/2023]
Abstract
Major depressive disorder (MDD) is a major international public health issue; thus, investigating its underlying mechanisms and identifying suitable biomarkers to enable its early detection are imperative. Using data-independent acquisition-mass spectrometry-based proteomics, the plasma of 44 patients with MDD and 25 healthy controls was studied to detect differentially expressed proteins. Bioinformatics analyses, such as Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis, Protein-Protein Interaction network, and weighted gene co-expression network analysis were employed. Moreover, an ensemble learning technique was used to build a prediction model. A panel of two biomarkers, L-selectin and an isoform of the Ras oncogene family was identified. With an area under the receiver operating characteristic curve of 0.925 and 0.901 for the training and test sets, respectively, the panel was able to distinguish MDD from the controls. Our investigation revealed numerous potential biomarkers and a diagnostic panel based on several algorithms, which may contribute to the future development of a plasma-based diagnostic approach and better understanding of the molecular mechanisms of MDD.
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Affiliation(s)
- Linna Zhang
- Department of Psychiatry, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Caiping Liu
- Department of Psychiatry, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yan Li
- Department of Psychiatry, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ying Wu
- Department of Psychiatry, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yumei Wei
- Department of Psychiatry, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Psychotic Disorders, Shanghai, China; Clinical Research Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Duan Zeng
- Department of Psychiatry, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shen He
- Department of Psychiatry, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Jingjing Huang
- Department of Psychiatry, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Huafang Li
- Department of Psychiatry, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Psychotic Disorders, Shanghai, China; Clinical Research Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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5
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Rahikkala E, Urpa L, Ghimire B, Topa H, Kurki MI, Koskela M, Airavaara M, Hämäläinen E, Pylkäs K, Körkkö J, Savolainen H, Suoranta A, Bertoli-Avella A, Rolfs A, Mattila P, Daly M, Palotie A, Pietiläinen O, Moilanen J, Kuismin O. A novel variant in SMG9 causes intellectual disability, confirming a role for nonsense-mediated decay components in neurocognitive development. Eur J Hum Genet 2022; 30:619-627. [PMID: 35087184 PMCID: PMC9090808 DOI: 10.1038/s41431-022-01046-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 12/04/2021] [Accepted: 01/11/2022] [Indexed: 12/13/2022] Open
Abstract
Biallelic loss-of-function variants in the SMG9 gene, encoding a regulatory subunit of the mRNA nonsense-mediated decay (NMD) machinery, are reported to cause heart and brain malformation syndrome. Here we report five patients from three unrelated families with intellectual disability (ID) and a novel pathogenic SMG9 c.551 T > C p.(Val184Ala) homozygous missense variant, identified using exome sequencing. Sanger sequencing confirmed recessive segregation in each family. SMG9 c.551T > C p.(Val184Ala) is most likely an autozygous variant identical by descent. Characteristic clinical findings in patients were mild to moderate ID, intention tremor, pyramidal signs, dyspraxia, and ocular manifestations. We used RNA sequencing of patients and age- and sex-matched healthy controls to assess the effect of the variant. RNA sequencing revealed that the SMG9 c.551T > C variant did not affect the splicing or expression level of SMG9 gene products, and allele-specific expression analysis did not provide evidence that the nonsense mRNA-induced NMD was affected. Differential gene expression analysis identified prevalent upregulation of genes in patients, including the genes SMOX, OSBP2, GPX3, and ZNF155. These findings suggest that normal SMG9 function may be involved in transcriptional regulation without affecting nonsense mRNA-induced NMD. In conclusion, we demonstrate that the SMG9 c.551T > C missense variant causes a neurodevelopmental disorder and impacts gene expression. NMD components have roles beyond aberrant mRNA degradation that are crucial for neurocognitive development.
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Affiliation(s)
- Elisa Rahikkala
- Department of Clinical Genetics, PEDEGO Research Unit and Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland.
- Institute of Biomedicine, University of Turku, Turku, Finland.
| | - Lea Urpa
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Bishwa Ghimire
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Hande Topa
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Mitja I Kurki
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
- Psychiatric & Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Boston, MA, USA
- The Stanley Center for Psychiatric Research, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Maryna Koskela
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Mikko Airavaara
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
- Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Eija Hämäläinen
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Katri Pylkäs
- Cancer and Translational Medicine Research Unit and Biocenter Oulu, University of Oulu, NordLab Oulu, Oulu, Finland
| | - Jarmo Körkkö
- Center for Intellectual Disability Care, Oulu University Hospital, Oulu, Finland
| | - Helena Savolainen
- Center for Intellectual Disability Care, Oulu University Hospital, Oulu, Finland
| | - Anu Suoranta
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | | | - Arndt Rolfs
- Centogene GmbH, 18055, Rostock, Germany
- Medical Faculty, University of Rostock, Rostock, Germany
| | - Pirkko Mattila
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Mark Daly
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
- Psychiatric & Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Boston, MA, USA
- The Stanley Center for Psychiatric Research, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Analytic and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Aarno Palotie
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
- Psychiatric & Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Boston, MA, USA
- The Stanley Center for Psychiatric Research, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Analytic and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Olli Pietiläinen
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
- The Stanley Center for Psychiatric Research, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Jukka Moilanen
- Department of Clinical Genetics, PEDEGO Research Unit and Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland
| | - Outi Kuismin
- Department of Clinical Genetics, PEDEGO Research Unit and Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
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Ke X, Liao Z, Luo X, Chen JQ, Deng M, Huang Y, Wang Z, Wei M. Endothelial colony-forming cell-derived exosomal miR-21-5p regulates autophagic flux to promote vascular endothelial repair by inhibiting SIPL1A2 in atherosclerosis. Cell Commun Signal 2022; 20:30. [PMID: 35279183 PMCID: PMC8917727 DOI: 10.1186/s12964-022-00828-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 01/07/2022] [Indexed: 12/12/2022] Open
Abstract
Abstract
Background
Percutaneous transluminal coronary angioplasty (PTCA) represents an efficient therapeutic method for atherosclerosis but conveys a risk of causing restenosis. Endothelial colony-forming cell-derived exosomes (ECFC-exosomes) are important mediators during vascular repair. This study aimed to investigate the therapeutic effects of ECFC-exosomes in a rat model of atherosclerosis and to explore the molecular mechanisms underlying the ECFC-exosome-mediated effects on ox-LDL-induced endothelial injury.
Methods
The effect of ECFC-exosome-mediated autophagy on ox-LDL-induced human microvascular endothelial cell (HMEC) injury was examined by cell counting kit-8 assay, scratch wound assay, tube formation assay, western blot and the Ad-mCherry-GFP-LC3B system. RNA-sequencing assays, bioinformatic analysis and dual-luciferase reporter assays were performed to confirm the interaction between the miR-21-5p abundance of ECFC-exosomes and SIPA1L2 in HMECs. The role and underlying mechanism of ECFC-exosomes in endothelial repair were explored using a high-fat diet combined with balloon injury to establish an atherosclerotic rat model of vascular injury. Evans blue staining, haematoxylin and eosin staining and western blotting were used to evaluate vascular injury.
Results
ECFC-exosomes were incorporated into HMECs and promoted HMEC proliferation, migration and tube formation by repairing autophagic flux and enhancing autophagic activity. Subsequently, we demonstrated that miR-21-5p, which is abundant in ECFC-exosomes, binds to the 3’ untranslated region of SIPA1L2 to inhibit its expression, and knockout of miR-21-5p in ECFC-exosomes reversed ECFC-exosome-decreased SIPA1L2 expression in ox-LDL-induced HMEC injury. Knockdown of SIPA1L2 repaired autophagic flux and enhanced autophagic activity to promote cell proliferation in ox-LDL-treated HMECs. ECFC-exosome treatment attenuated vascular endothelial injury, regulated lipid balance and activated autophagy in an atherogenic rat model of vascular injury, whereas these effects were eliminated with ECFC-exosomes with knockdown of miR-21-5p.
Conclusions
Our study demonstrated that ECFC-exosomes protect against atherosclerosis- or PTCA-induced vascular injury by rescuing autophagic flux and inhibiting SIAP1L2 expression through delivery of miR-21-5p.
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Li Y, Deng P, Chen C, Ma Q, Pi H, He M, Lu Y, Gao P, Zhou C, He Z, Zhang Y, Yu Z, Zhang L. 1,800 MHz Radiofrequency Electromagnetic Irradiation Impairs Neurite Outgrowth With a Decrease in Rap1-GTP in Primary Mouse Hippocampal Neurons and Neuro2a Cells. Front Public Health 2021; 9:771508. [PMID: 34881219 PMCID: PMC8646047 DOI: 10.3389/fpubh.2021.771508] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 09/06/2021] [Accepted: 10/29/2021] [Indexed: 12/23/2022] Open
Abstract
Background: With the global popularity of communication devices such as mobile phones, there are increasing concerns regarding the effect of radiofrequency electromagnetic radiation (RF-EMR) on the brain, one of the most important organs sensitive to RF-EMR exposure at 1,800 MHz. However, the effects of RF-EMR exposure on neuronal cells are unclear. Neurite outgrowth plays a critical role in brain development, therefore, determining the effects of 1,800 MHz RF-EMR exposure on neurite outgrowth is important for exploring its effects on brain development. Objectives: We aimed to investigate the effects of 1,800 MHz RF-EMR exposure for 48 h on neurite outgrowth in neuronal cells and to explore the associated role of the Rap1 signaling pathway. Material and Methods: Primary hippocampal neurons from C57BL/6 mice and Neuro2a cells were exposed to 1,800 MHz RF-EMR at a specific absorption rate (SAR) value of 4 W/kg for 48 h. CCK-8 assays were used to determine the cell viability after 24, 48, and 72 h of irradiation. Neurite outgrowth of primary hippocampal neurons (DIV 2) and Neuro2a cells was observed with a 20 × optical microscope and recognized by ImageJ software. Rap1a and Rap1b gene expressions were detected by real-time quantitative PCR. Rap1, Rap1a, Rap1b, Rap1GAP, and p-MEK1/2 protein expressions were detected by western blot. Rap1-GTP expression was detected by immunoprecipitation. The role of Rap1-GTP was assessed by transfecting a constitutively active mutant plasmid (Rap1-Gly_Val-GFP) into Neuro2a cells. Results: Exposure to 1,800 MHz RF-EMR for 24, 48, and 72 h at 4 W/kg did not influence cell viability. The neurite length, primary and secondary neurite numbers, and branch points of primary mouse hippocampal neurons were significantly impaired by 48-h RF-EMR exposure. The neurite-bearing cell percentage and neurite length of Neuro2a cells were also inhibited by 48-h RF-EMR exposure. Rap1 activity was inhibited by 48-h RF-EMR with no detectable alteration in either gene or protein expression of Rap1. The protein expression of Rap1GAP increased after 48-h RF-EMR exposure, while the expression of p-MEK1/2 protein decreased. Overexpression of constitutively active Rap1 reversed the decrease in Rap1-GTP and the neurite outgrowth impairment in Neuro2a cells induced by 1,800 MHz RF-EMR exposure for 48 h. Conclusion: Rap1 activity and related signaling pathways are involved in the disturbance of neurite outgrowth induced by 48-h 1,800 MHz RF-EMR exposure. The effects of RF-EMR exposure on neuronal development in infants and children deserve greater focus.
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Affiliation(s)
- Yanqi Li
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Department of Occupational Health, Ministry of Education, Third Military Medical University, Chongqing, China
| | - Ping Deng
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Department of Occupational Health, Ministry of Education, Third Military Medical University, Chongqing, China
| | - Chunhai Chen
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Department of Occupational Health, Ministry of Education, Third Military Medical University, Chongqing, China
| | - Qinlong Ma
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Department of Occupational Health, Ministry of Education, Third Military Medical University, Chongqing, China
| | - Huifeng Pi
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Department of Occupational Health, Ministry of Education, Third Military Medical University, Chongqing, China
| | - Mindi He
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Department of Occupational Health, Ministry of Education, Third Military Medical University, Chongqing, China
| | - Yonghui Lu
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Department of Occupational Health, Ministry of Education, Third Military Medical University, Chongqing, China
| | - Peng Gao
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Department of Occupational Health, Ministry of Education, Third Military Medical University, Chongqing, China
| | - Chao Zhou
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Department of Occupational Health, Ministry of Education, Third Military Medical University, Chongqing, China
| | - Zhixin He
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Department of Occupational Health, Ministry of Education, Third Military Medical University, Chongqing, China
| | - Yanwen Zhang
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Department of Occupational Health, Ministry of Education, Third Military Medical University, Chongqing, China
| | - Zhengping Yu
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Department of Occupational Health, Ministry of Education, Third Military Medical University, Chongqing, China
| | - Lei Zhang
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Department of Occupational Health, Ministry of Education, Third Military Medical University, Chongqing, China
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8
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Yang D, Zhou H, Lin J, Zhao S, Zhou H, Yin Z, Ni B, Chen Y, Xie W. Case Report: A Novel Missense Variant in the SIPA1L3 Gene Associated With Cataracts in a Chinese Family. Front Genet 2021; 12:715599. [PMID: 34603379 PMCID: PMC8481882 DOI: 10.3389/fgene.2021.715599] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/19/2021] [Indexed: 11/23/2022] Open
Abstract
The signal-induced proliferation-associated 1-like 3 (SIPA1L3) gene that encodes a putative Rap GTPase-activating protein (RapGAP) has been associated with congenital cataract and eye development abnormalities. However, our current understanding of the mutation spectrum of SIPA1L3 associated with eye defects is limited. By using whole-exome sequencing plus Sanger sequencing validation, we identified a novel heterozygous c.1871A > G (p.Lys624Arg) variation within the predicted RapGAP domain of SIPA1L3 in the proband with isolated juvenile-onset cataracts from a three-generation Chinese family. In this family, the proband's father and grandmother were also heterozygous for the c.1871A > G variation and affected by cataracts varying in morphology, severity, and age of onset. Sequence alignment shows that the Lys 624 residue of SIPA1L3 is conserved across the species. Based on the resolved structure of Rap1–Rap1GAP complex, homology modeling implies that the Lys 624 residue is structurally homologous to the Lys 194 of Rap1GAP, a highly conserved lysine residue that is involved in the interface between Rap1 and Rap1GAP and critical for the affinity to Rap·GTP. We reasoned that arginine substitution of lysine 624 might have an impact on the SIPA1L3-Rap·GTP interaction, thereby affecting the regulatory function of SIPA1L3 on Rap signaling. Collectively, our finding expands the mutation spectrum of SIPA1L3 and provides new clues to the molecular mechanisms of SIPA1L3-related cataracts. Further investigations are warranted to validate the functional alteration of the p.Lys624Arg variant of SIPA1L3.
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Affiliation(s)
- Duo Yang
- Department of Ophthalmology, The Jili Hospital of Liuyang and the Eye Hospital of Liuyang, Changsha, China
| | - Haiyan Zhou
- National Health Committee Key Laboratory of Birth Defects for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
| | - Jiwu Lin
- National Health Committee Key Laboratory of Birth Defects for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
| | - Shuangxi Zhao
- Department of Ophthalmology, The Jili Hospital of Liuyang and the Eye Hospital of Liuyang, Changsha, China
| | - Hao Zhou
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Science, College of Life Sciences, Nankai University, Tianjin, China
| | - Zhaochu Yin
- National Health Committee Key Laboratory of Birth Defects for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
| | - Bin Ni
- National Health Committee Key Laboratory of Birth Defects for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
| | - Yong Chen
- National Health Committee Key Laboratory of Birth Defects for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
| | - Wanqin Xie
- National Health Committee Key Laboratory of Birth Defects for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
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9
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Kaneko K, Lin HY, Fu Y, Saha PK, De la Puente-Gomez AB, Xu Y, Ohinata K, Chen P, Morozov A, Fukuda M. Rap1 in the VMH regulates glucose homeostasis. JCI Insight 2021; 6:142545. [PMID: 33974562 PMCID: PMC8262364 DOI: 10.1172/jci.insight.142545] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 05/05/2021] [Indexed: 12/14/2022] Open
Abstract
The hypothalamus is a critical regulator of glucose metabolism and is capable of correcting diabetes conditions independently of an effect on energy balance. The small GTPase Rap1 in the forebrain is implicated in high-fat diet–induced (HFD-induced) obesity and glucose imbalance. Here, we report that increasing Rap1 activity selectively in the medial hypothalamus elevated blood glucose without increasing the body weight of HFD-fed mice. In contrast, decreasing hypothalamic Rap1 activity protected mice from diet-induced hyperglycemia but did not prevent weight gain. The remarkable glycemic effect of Rap1 was reproduced when Rap1 was specifically deleted in steroidogenic factor-1–positive (SF-1–positive) neurons in the ventromedial hypothalamic nucleus (VMH) known to regulate glucose metabolism. While having no effect on body weight regardless of sex, diet, and age, Rap1 deficiency in the VMH SF1 neurons markedly lowered blood glucose and insulin levels, improved glucose and insulin tolerance, and protected mice against HFD-induced neural leptin resistance and peripheral insulin resistance at the cellular and whole-body levels. Last, acute pharmacological inhibition of brain exchange protein directly activated by cAMP 2, a direct activator of Rap1, corrected glucose imbalance in obese mouse models. Our findings uncover the primary role of VMH Rap1 in glycemic control and implicate Rap1 signaling as a potential target for therapeutic intervention in diabetes.
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Affiliation(s)
- Kentaro Kaneko
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Hsiao-Yun Lin
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Yukiko Fu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Department of Molecular Medicine and Metabolism, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | | | - Ana B De la Puente-Gomez
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Yong Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Kousaku Ohinata
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Peter Chen
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Women's Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Alexei Morozov
- Unit on Behavioral Genetics, Laboratory of Molecular Pathophysiology, National Institute of Mental Health, NIH, Maryland, USA.,Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, USA
| | - Makoto Fukuda
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
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10
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Bentley SR, Guella I, Sherman HE, Neuendorf HM, Sykes AM, Fowdar JY, Silburn PA, Wood SA, Farrer MJ, Mellick GD. Hunting for Familial Parkinson's Disease Mutations in the Post Genome Era. Genes (Basel) 2021; 12:430. [PMID: 33802862 DOI: 10.3390/genes12030430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/12/2021] [Accepted: 03/13/2021] [Indexed: 11/20/2022] Open
Abstract
Parkinson’s disease (PD) is typically sporadic; however, multi-incident families provide a powerful platform to discover novel genetic forms of disease. Their identification supports deciphering molecular processes leading to disease and may inform of new therapeutic targets. The LRRK2 p.G2019S mutation causes PD in 42.5–68% of carriers by the age of 80 years. We hypothesise similarly intermediately penetrant mutations may present in multi-incident families with a generally strong family history of disease. We have analysed six multiplex families for missense variants using whole exome sequencing to find 32 rare heterozygous mutations shared amongst affected members. Included in these mutations was the KCNJ15 p.R28C variant, identified in five affected members of the same family, two elderly unaffected members of the same family, and two unrelated PD cases. Additionally, the SIPA1L1 p.R236Q variant was identified in three related affected members and an unrelated familial case. While the evidence presented here is not sufficient to assign causality to these rare variants, it does provide novel candidates for hypothesis testing in other modestly sized families with a strong family history. Future analysis will include characterisation of functional consequences and assessment of carriers in other familial cases.
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11
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Abstract
Phosphodiesterases (PDEs) are enzymes involved in the homeostasis of both cAMP and cGMP. They are members of a family of proteins that includes 11 subfamilies with different substrate specificities. Their main function is to catalyze the hydrolysis of cAMP, cGMP, or both. cAMP and cGMP are two key second messengers that modulate a wide array of intracellular processes and neurobehavioral functions, including memory and cognition. Even if these enzymes are present in all tissues, we focused on those PDEs that are expressed in the brain. We took into consideration genetic variants in patients affected by neurodevelopmental disorders, phenotypes of animal models, and pharmacological effects of PDE inhibitors, a class of drugs in rapid evolution and increasing application to brain disorders. Collectively, these data indicate the potential of PDE modulators to treat neurodevelopmental diseases characterized by learning and memory impairment, alteration of behaviors associated with depression, and deficits in social interaction. Indeed, clinical trials are in progress to treat patients with Alzheimer's disease, schizophrenia, depression, and autism spectrum disorders. Among the most recent results, the application of some PDE inhibitors (PDE2A, PDE3, PDE4/4D, and PDE10A) to treat neurodevelopmental diseases, including autism spectrum disorders and intellectual disability, is a significant advance, since no specific therapies are available for these disorders that have a large prevalence. In addition, to highlight the role of several PDEs in normal and pathological neurodevelopment, we focused here on the deregulation of cAMP and/or cGMP in Down Syndrome, Fragile X Syndrome, Rett Syndrome, and intellectual disability associated with the CC2D1A gene.
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Affiliation(s)
- Sébastien Delhaye
- grid.429194.30000 0004 0638 0649Université Côte d’Azur, CNRS UMR7275, Institute of Molecular and Cellular Pharmacology, 06560 Valbonne, France
| | - Barbara Bardoni
- Université Côte d'Azur, Inserm, CNRS UMR7275, Institute of Molecular and Cellular Pharmacology, 06560, Valbonne, France.
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12
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Chen WB, Pan HQ, He Y, Wang XH, Zhang WH, Pan BX. Rap1b but not Rap1a in the forebrain is required for learned fear. Cell Biosci 2020; 10:107. [PMID: 32944221 PMCID: PMC7488763 DOI: 10.1186/s13578-020-00469-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [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: 08/07/2020] [Accepted: 09/04/2020] [Indexed: 11/10/2022] Open
Abstract
Background Fear is an adaptive response across species in the face of threatening cues. It can be either innate or learned through postnatal experience. We have previously shown that genetic deletion of both Rap1a and Rap1b, two isoforms of small GTPase Rap1 in forebrain, causes impairment in auditory fear conditioning. However, the specific roles of these two isoforms are not yet known. Results In the present study, employing mice with forebrain-restricted deletion of Rap1a or Rap1b, we found that they are both dispensable for normal acquisition of fear learning. However, Rap1b but not Rap1a knockout (KO) mice displayed impairment in the retrieval of learned fear. Subsequently, we found that the expression of c-Fos, a marker of neuronal activity, is specifically decreased in prelimbic cortex (PL) of Rap1b KO mice after auditory fear conditioning, while remained unaltered in the amygdala and infralimbic cortex (IL). On the other hand, neither Rap1a nor Rap1b knockout altered the innate fear of mice in response to their predator odor, 2,5-Dihydro-2,4,5-Trimethylthiazoline (TMT). Conclusion Thus, our results indicate that it is Rap1b but not Rap1a involved in the retrieval process of fear learning, and the learned but not innate fear requires Rap1 signaling in forebrain.
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Affiliation(s)
- Wen-Bing Chen
- School of Life Sciences, Nanchang University, Nanchang, 330031 China.,Institute of Life Science, Nanchang University, Nanchang, 330031 China
| | - Han-Qing Pan
- School of Life Sciences, Nanchang University, Nanchang, 330031 China.,Institute of Life Science, Nanchang University, Nanchang, 330031 China
| | - Ye He
- Institute of Life Science, Nanchang University, Nanchang, 330031 China.,Center for Basic Medical Experiment, Nanchang University, Nanchang, 330031 China
| | - Xue-Hui Wang
- School of Life Sciences, Nanchang University, Nanchang, 330031 China.,Institute of Life Science, Nanchang University, Nanchang, 330031 China
| | - Wen-Hua Zhang
- Institute of Life Science, Nanchang University, Nanchang, 330031 China
| | - Bing-Xing Pan
- School of Life Sciences, Nanchang University, Nanchang, 330031 China.,Institute of Life Science, Nanchang University, Nanchang, 330031 China.,Department of Ophthalmology, The 2nd Affiliated Hospital of Nanchang University, Nanchang, 330006 China
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13
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Tao F, Beecham GW, Rebelo AP, Svaren J, Blanton SH, Moran JJ, Lopez-Anido C, Morrow JM, Abreu L, Rizzo D, Kirk CA, Wu X, Feely S, Verhamme C, Saporta MA, Herrmann DN, Day JW, Sumner CJ, Lloyd TE, Li J, Yum SW, Taroni F, Baas F, Choi BO, Pareyson D, Scherer SS, Reilly MM, Shy ME, Züchner S. Variation in SIPA1L2 is correlated with phenotype modification in Charcot- Marie- Tooth disease type 1A. Ann Neurol 2020; 85:316-330. [PMID: 30706531 DOI: 10.1002/ana.25426] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 01/29/2019] [Accepted: 01/30/2019] [Indexed: 01/28/2023]
Abstract
OBJECTIVE Genetic modifiers in rare disease have long been suspected to contribute to the considerable variance in disease expression, including Charcot-Marie-Tooth disease type 1A (CMT1A). To address this question, the Inherited Neuropathy Consortium collected a large standardized sample of such rare CMT1A patients over a period of 8 years. CMT1A is caused in most patients by a uniformly sized 1.5 Mb duplication event involving the gene PMP22. METHODS We genotyped DNA samples from 971 CMT1A patients on Illumina BeadChips. Genome-wide analysis was performed in a subset of 330 of these patients, who expressed the extremes of a hallmark symptom: mild and severe foot dorsiflexion strength impairment. SIPA1L2 (signal-induced proliferation-associated 1 like 2), the top identified candidate modifier gene, was expressed in the peripheral nerve, and our functional studies identified and confirmed interacting proteins using coimmunoprecipitation analysis, mass spectrometry, and immunocytochemistry. Chromatin immunoprecipitation and in vitro siRNA experiments were used to analyze gene regulation. RESULTS We identified significant association of 4 single nucleotide polymorphisms (rs10910527, rs7536385, rs4649265, rs1547740) in SIPA1L2 with foot dorsiflexion strength (p < 1 × 10-7 ). Coimmunoprecipitation and mass spectroscopy studies identified β-actin and MYH9 as SIPA1L2 binding partners. Furthermore, we show that SIPA1L2 is part of a myelination-associated coexpressed network regulated by the master transcription factor SOX10. Importantly, in vitro knockdown of SIPA1L2 in Schwannoma cells led to a significant reduction of PMP22 expression, hinting at a potential strategy for drug development. INTERPRETATION SIPA1L2 is a potential genetic modifier of CMT1A phenotypic expressions and offers a new pathway to therapeutic interventions. ANN NEUROL 2019;85:316-330.
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Affiliation(s)
- Feifei Tao
- Department for Human Genetics and Hussman Institute for Human Genomics, University of Miami, Miami, FL
| | - Gary W Beecham
- Department for Human Genetics and Hussman Institute for Human Genomics, University of Miami, Miami, FL
| | - Adriana P Rebelo
- Department for Human Genetics and Hussman Institute for Human Genomics, University of Miami, Miami, FL
| | - John Svaren
- Department of Comparative Biosciences and Waisman Center, University of Wisconsin, Madison, WI
| | - Susan H Blanton
- Department for Human Genetics and Hussman Institute for Human Genomics, University of Miami, Miami, FL
| | - John J Moran
- Department of Comparative Biosciences and Waisman Center, University of Wisconsin, Madison, WI
| | - Camila Lopez-Anido
- Department of Comparative Biosciences and Waisman Center, University of Wisconsin, Madison, WI
| | - Jasper M Morrow
- Medical Research Council Centre for Neuromuscular Diseases, University College London Institute of Neurology, London, United Kingdom
| | - Lisa Abreu
- Department for Human Genetics and Hussman Institute for Human Genomics, University of Miami, Miami, FL
| | - Devon Rizzo
- Data Management and Coordinating Center, Rare Diseases Clinical Research Network, Pediatrics Epidemiology Center, University of South Florida, Tampa, FL
| | - Callyn A Kirk
- Data Management and Coordinating Center, Rare Diseases Clinical Research Network, Pediatrics Epidemiology Center, University of South Florida, Tampa, FL
| | - Xingyao Wu
- Department of Neurology, University of Iowa, Iowa City, IA
| | - Shawna Feely
- Department of Neurology, University of Iowa, Iowa City, IA
| | - Camiel Verhamme
- Department of Neurology, Academic Medical Center, Amsterdam, the Netherlands
| | | | | | - John W Day
- Department of Neurology, Stanford University, Palo Alto, CA
| | - Charlotte J Sumner
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD.,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Thomas E Lloyd
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD.,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Jun Li
- Department of Neurology, Wayne State University School of Medicine, Detroit, MI
| | - Sabrina W Yum
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Franco Taroni
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Foundation Carlo Besta Neurological Institute, Milan, Italy
| | - Frank Baas
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Davide Pareyson
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Foundation Carlo Besta Neurological Institute, Milan, Italy
| | - Steven S Scherer
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Mary M Reilly
- Medical Research Council Centre for Neuromuscular Diseases, University College London Institute of Neurology, London, United Kingdom
| | - Michael E Shy
- Department of Neurology, University of Iowa, Iowa City, IA
| | - Stephan Züchner
- Department for Human Genetics and Hussman Institute for Human Genomics, University of Miami, Miami, FL
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14
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Andres-Alonso M, Ammar MR, Butnaru I, Gomes GM, Acuña Sanhueza G, Raman R, Yuanxiang P, Borgmeyer M, Lopez-Rojas J, Raza SA, Brice N, Hausrat TJ, Macharadze T, Diaz-Gonzalez S, Carlton M, Failla AV, Stork O, Schweizer M, Gundelfinger ED, Kneussel M, Spilker C, Karpova A, Kreutz MR. SIPA1L2 controls trafficking and local signaling of TrkB-containing amphisomes at presynaptic terminals. Nat Commun 2019; 10:5448. [PMID: 31784514 DOI: 10.1038/s41467-019-13224-z] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 10/28/2019] [Indexed: 12/31/2022] Open
Abstract
Amphisomes are organelles of the autophagy pathway that result from the fusion of autophagosomes with late endosomes. While biogenesis of autophagosomes and late endosomes occurs continuously at axon terminals, non-degradative roles of autophagy at boutons are barely described. Here, we show that in neurons BDNF/TrkB traffick in amphisomes that signal locally at presynaptic boutons during retrograde transport to the soma. This is orchestrated by the Rap GTPase-activating (RapGAP) protein SIPA1L2, which connects TrkB amphisomes to a dynein motor. The autophagosomal protein LC3 regulates RapGAP activity of SIPA1L2 and controls retrograde trafficking and local signaling of TrkB. Following induction of presynaptic plasticity, amphisomes dissociate from dynein at boutons enabling local signaling and promoting transmitter release. Accordingly, sipa1l2 knockout mice show impaired BDNF-dependent presynaptic plasticity. Taken together, the data suggest that in hippocampal neurons, TrkB-signaling endosomes are in fact amphisomes that during retrograde transport have local signaling capacity in the context of presynaptic plasticity. There is growing evidence that autophagy might serve specialized functions in neurons besides its role in protein homeostasis. In this study, authors demonstrate that axonal retrograde transport of BDNF/TrkB in neuronal amphisomes is involved in plasticity-relevant local signaling at presynaptic boutons and that SIPA1L2, a member of the SIPA1L family of neuronal RapGAPs, associates via LC3b to TrkB-containing amphisomes to regulate its motility and signaling at the axon terminals
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15
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Alugubelly N, Mohammad AN, Edelmann MJ, Nanduri B, Sayed M, Park JW, Carr RL. Proteomic and transcriptional profiling of rat amygdala following social play. Behav Brain Res 2019; 376:112210. [PMID: 31493430 DOI: 10.1016/j.bbr.2019.112210] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [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: 03/20/2019] [Revised: 09/03/2019] [Accepted: 09/03/2019] [Indexed: 12/31/2022]
Abstract
Social play is the most characteristic form of social interaction which is necessary for adolescents to develop proper cognitive, emotional, and social competency. The information available on neural substrates and the mechanism involved in social play is limited. This study characterized social play by proteomic and transcriptional profiling studies. Social play was performed on male Sprague Dawley rats on postnatal day 38 and protein and gene expression in the amygdala was determined following behavioral testing. The proteomic analysis led to the identification of 170 differentially expressed proteins (p ≤ 0.05) with 67 upregulated and 103 downregulated proteins. The transcriptomic analysis led to the identification of 188 genes (FDR ≤ 0.05) with 55 upregulated and 133 downregulated genes. DAVID analysis of gene/protein expression data revealed that social play altered GABAergic signaling, glutamatergic signaling, and G-protein coupled receptor (GPCR) signaling. These data suggest that the synaptic levels of GABA and glutamate increased during play. Ingenuity Pathway Analysis (IPA) confirmed these alterations. IPA also revealed that differentially expressed genes/proteins in our data had significant over representation of neurotransmitter signaling systems, including the opioid, serotonin, and dopamine systems, suggesting that play alters the systems involved in the regulation of reward. In addition, corticotropin-releasing hormone signaling was altered indicating that an increased level of stress occurs during play. Overall, our data suggest that increased inhibitory GPCR signaling in these neurotransmitter pathways occurs following social play as a physiological response to regulate the induced level of reward and stress and to maintain the excitatory-inhibitory balance in the neurotransmitter systems.
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Affiliation(s)
- Navatha Alugubelly
- Center for Environmental Health Sciences, MS, USA; Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - Afzaal N Mohammad
- Center for Environmental Health Sciences, MS, USA; Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - Mariola J Edelmann
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, USA
| | - Bindu Nanduri
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - Mohammed Sayed
- Department of Computer Engineering and Computer Science, KY, USA
| | - Juw Won Park
- Department of Computer Engineering and Computer Science, KY, USA; KBRIN Bioinformatics Core, University of Louisville, KY, USA.
| | - Russell L Carr
- Center for Environmental Health Sciences, MS, USA; Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA.
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16
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Schwartzentruber J, Foskolou S, Kilpinen H, Rodrigues J, Alasoo K, Knights AJ, Patel M, Goncalves A, Ferreira R, Benn CL, Wilbrey A, Bictash M, Impey E, Cao L, Lainez S, Loucif AJ, Whiting PJ, Gutteridge A, Gaffney DJ. Molecular and functional variation in iPSC-derived sensory neurons. Nat Genet 2018; 50:54-61. [PMID: 29229984 PMCID: PMC5742539 DOI: 10.1038/s41588-017-0005-8] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 11/06/2017] [Indexed: 12/20/2022]
Abstract
Induced pluripotent stem cells (iPSCs), and cells derived from them, have become key tools for modeling biological processes, particularly in cell types that are difficult to obtain from living donors. Here we present a map of regulatory variants in iPSC-derived neurons, based on 123 differentiations of iPSCs to a sensory neuronal fate. Gene expression was more variable across cultures than in primary dorsal root ganglion, particularly for genes related to nervous system development. Using single-cell RNA-sequencing, we found that the number of neuronal versus contaminating cells was influenced by iPSC culture conditions before differentiation. Despite high differentiation-induced variability, our allele-specific method detected thousands of quantitative trait loci (QTLs) that influenced gene expression, chromatin accessibility, and RNA splicing. On the basis of these detected QTLs, we estimate that recall-by-genotype studies that use iPSC-derived cells will require cells from at least 20-80 individuals to detect the effects of regulatory variants with moderately large effect sizes.
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Affiliation(s)
- Jeremy Schwartzentruber
- Wellcome Trust Sanger Institute, Hinxton, UK.
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, UK.
| | - Stefanie Foskolou
- Pfizer Neuroscience and Pain Research Unit, Pfizer Ltd., Cambridge, UK
| | - Helena Kilpinen
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, UK
| | | | - Kaur Alasoo
- Wellcome Trust Sanger Institute, Hinxton, UK
| | | | - Minal Patel
- Wellcome Trust Sanger Institute, Hinxton, UK
| | | | - Rita Ferreira
- Pfizer Neuroscience and Pain Research Unit, Pfizer Ltd., Cambridge, UK
| | | | - Anna Wilbrey
- Pfizer Neuroscience and Pain Research Unit, Pfizer Ltd., Cambridge, UK
| | - Magda Bictash
- Pfizer Neuroscience and Pain Research Unit, Pfizer Ltd., Cambridge, UK
| | - Emma Impey
- Pfizer Neuroscience and Pain Research Unit, Pfizer Ltd., Cambridge, UK
| | - Lishuang Cao
- Pfizer Neuroscience and Pain Research Unit, Pfizer Ltd., Cambridge, UK
| | - Sergio Lainez
- Pfizer Neuroscience and Pain Research Unit, Pfizer Ltd., Cambridge, UK
| | | | - Paul John Whiting
- Pfizer Neuroscience and Pain Research Unit, Pfizer Ltd., Cambridge, UK
- AR-UK Drug Discovery Institute, Institute of Neurology, University College London, London, UK
| | - Alex Gutteridge
- Pfizer Neuroscience and Pain Research Unit, Pfizer Ltd., Cambridge, UK.
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17
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Basken J, Stuart SA, Kavran AJ, Lee T, Ebmeier CC, Old WM, Ahn NG. Specificity of Phosphorylation Responses to Mitogen Activated Protein (MAP) Kinase Pathway Inhibitors in Melanoma Cells. Mol Cell Proteomics 2017; 17:550-564. [PMID: 29255136 DOI: 10.1074/mcp.ra117.000335] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 11/08/2017] [Indexed: 01/01/2023] Open
Abstract
The BRAF-MKK1/2-ERK1/2 pathway is constitutively activated in response to oncogenic mutations of BRAF in many cancer types, including melanoma. Although small molecules that inhibit oncogenic BRAF and MAP kinase kinase (MKK)1/2 have been successful in clinical settings, resistance invariably develops. High affinity inhibitors of ERK1/2 have been shown in preclinical studies to bypass the resistance of melanoma and colon cancer cells to BRAF and MKK1/2 inhibitors, and are thus promising additions to current treatment protocols. But still unknown is how molecular responses to ERK1/2 inhibitors compare with inhibitors currently in clinical use. Here, we employ quantitative phosphoproteomics to evaluate changes in phosphorylation in response to the ERK inhibitors, SCH772984 and GDC0994, and compare these to the clinically used MKK1/2 inhibitor, trametinib. Combined with previous studies measuring phosphoproteomic responses to the MKK1/2 inhibitor, selumetinib, and the BRAF inhibitor, vemurafenib, the outcomes reveal key insights into pathway organization, phosphorylation specificity and off-target effects of these inhibitors. The results demonstrate linearity in signaling from BRAF to MKK1/2 and from MKK1/2 to ERK1/2. They identify likely targets of direct phosphorylation by ERK1/2, as well as inhibitor off-targets, including an off-target regulation of the p38α mitogen activated protein kinase (MAPK) pathway by the MKK1/2 inhibitor, trametinib, at concentrations used in the literature but higher than in vivo drug concentrations. In addition, several known phosphorylation targets of ERK1/2 are insensitive to MKK or ERK inhibitors, revealing variability in canonical pathway responses between different cell systems. By comparing multiple inhibitors targeted to multiple tiers of protein kinases in the MAPK pathway, we gain insight into regulation and new targets of the oncogenic BRAF driver pathway in cancer cells, and a useful approach for evaluating the specificity of drugs and drug candidates.
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Affiliation(s)
- Joel Basken
- From the ‡Department of Chemistry and Biochemistry
| | | | - Andrew J Kavran
- From the ‡Department of Chemistry and Biochemistry.,§BioFrontiers Institute
| | - Thomas Lee
- From the ‡Department of Chemistry and Biochemistry
| | - Christopher C Ebmeier
- ¶Department of Molecular, Cellular, Developmental Biology, University of Colorado, Boulder, CO 80303
| | - William M Old
- ¶Department of Molecular, Cellular, Developmental Biology, University of Colorado, Boulder, CO 80303
| | - Natalie G Ahn
- From the ‡Department of Chemistry and Biochemistry, .,§BioFrontiers Institute
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18
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Kaneko K, Xu P, Cordonier EL, Chen SS, Ng A, Xu Y, Morozov A, Fukuda M. Neuronal Rap1 Regulates Energy Balance, Glucose Homeostasis, and Leptin Actions. Cell Rep 2017; 16:3003-3015. [PMID: 27626668 DOI: 10.1016/j.celrep.2016.08.039] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 06/30/2016] [Accepted: 08/11/2016] [Indexed: 10/21/2022] Open
Abstract
The CNS contributes to obesity and metabolic disease; however, the underlying neurobiological pathways remain to be fully established. Here, we show that the small GTPase Rap1 is expressed in multiple hypothalamic nuclei that control whole-body metabolism and is activated in high-fat diet (HFD)-induced obesity. Genetic ablation of CNS Rap1 protects mice from dietary obesity, glucose imbalance, and insulin resistance in the periphery and from HFD-induced neuropathological changes in the hypothalamus, including diminished cellular leptin sensitivity and increased endoplasmic reticulum (ER) stress and inflammation. Furthermore, pharmacological inhibition of CNS Rap1 signaling normalizes hypothalamic ER stress and inflammation, improves cellular leptin sensitivity, and reduces body weight in mice with dietary obesity. We also demonstrate that Rap1 mediates leptin resistance via interplay with ER stress. Thus, neuronal Rap1 critically regulates leptin sensitivity and mediates HFD-induced obesity and hypothalamic pathology and may represent a potential therapeutic target for obesity treatment.
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Affiliation(s)
- Kentaro Kaneko
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Pingwen Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Elizabeth L Cordonier
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Siyu S Chen
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Amy Ng
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yong Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Cellular Biology, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA
| | - Alexei Morozov
- Unit on Behavioral Genetics, Laboratory of Molecular Pathophysiology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA; Virginia Tech Carilion Research Institute, Roanoke, VA 24016, USA
| | - Makoto Fukuda
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.
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19
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Jordán-Álvarez S, Santana E, Casas-Tintó S, Acebes Á, Ferrús A. The equilibrium between antagonistic signaling pathways determines the number of synapses in Drosophila. PLoS One 2017; 12:e0184238. [PMID: 28892511 PMCID: PMC5593197 DOI: 10.1371/journal.pone.0184238] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 08/21/2017] [Indexed: 12/12/2022] Open
Abstract
The number of synapses is a major determinant of behavior and many neural diseases exhibit deviations in that number. However, how signaling pathways control this number is still poorly understood. Using the Drosophila larval neuromuscular junction, we show here a PI3K-dependent pathway for synaptogenesis which is functionally connected with other previously known elements including the Wit receptor, its ligand Gbb, and the MAPkinases cascade. Based on epistasis assays, we determined the functional hierarchy within the pathway. Wit seems to trigger signaling through PI3K, and Ras85D also contributes to the initiation of synaptogenesis. However, contrary to other signaling pathways, PI3K does not require Ras85D binding in the context of synaptogenesis. In addition to the MAPK cascade, Bsk/JNK undergoes regulation by Puc and Ras85D which results in a narrow range of activity of this kinase to determine normalcy of synapse number. The transcriptional readout of the synaptogenesis pathway involves the Fos/Jun complex and the repressor Cic. In addition, we identified an antagonistic pathway that uses the transcription factors Mad and Medea and the microRNA bantam to down-regulate key elements of the pro-synaptogenesis pathway. Like its counterpart, the anti-synaptogenesis signaling uses small GTPases and MAPKs including Ras64B, Ras-like-a, p38a and Licorne. Bantam downregulates the pro-synaptogenesis factors PI3K, Hiw, Ras85D and Bsk, but not AKT. AKT, however, can suppress Mad which, in conjunction with the reported suppression of Mad by Hiw, closes the mutual regulation between both pathways. Thus, the number of synapses seems to result from the balanced output from these two pathways.
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Affiliation(s)
| | | | | | - Ángel Acebes
- Institute Cajal C.S.I.C., Madrid, Spain
- * E-mail: (AF); (AA)
| | - Alberto Ferrús
- Institute Cajal C.S.I.C., Madrid, Spain
- * E-mail: (AF); (AA)
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20
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Laguesse S, Morisot N, Shin JH, Liu F, Adrover MF, Sakhai SA, Lopez MF, Phamluong K, Griffin WC, Becker HC, Bender KJ, Alvarez VA, Ron D. Prosapip1-Dependent Synaptic Adaptations in the Nucleus Accumbens Drive Alcohol Intake, Seeking, and Reward. Neuron 2017; 96:145-159.e8. [PMID: 28890345 DOI: 10.1016/j.neuron.2017.08.037] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [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: 02/02/2017] [Revised: 06/13/2017] [Accepted: 08/24/2017] [Indexed: 12/15/2022]
Abstract
The mammalian target of rapamycin complex 1 (mTORC1), a transducer of local dendritic translation, participates in learning and memory processes as well as in mechanisms underlying alcohol-drinking behaviors. Using an unbiased RNA-seq approach, we identified Prosapip1 as a novel downstream target of mTORC1 whose translation and consequent synaptic protein expression are increased in the nucleus accumbens (NAc) of mice excessively consuming alcohol. We demonstrate that alcohol-dependent increases in Prosapip1 levels promote the formation of actin filaments, leading to changes in dendritic spine morphology of NAc medium spiny neurons (MSNs). We further demonstrate that Prosapip1 is required for alcohol-dependent synaptic localization of GluA2 lacking AMPA receptors in NAc shell MSNs. Finally, we present data implicating Prosapip1 in mechanisms underlying alcohol self-administration and reward. Together, these data suggest that Prosapip1 in the NAc is a molecular transducer of structural and synaptic alterations that drive and/or maintain excessive alcohol use.
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Affiliation(s)
- Sophie Laguesse
- Department of Neurology, University of California, San Francisco, CA, USA
| | - Nadege Morisot
- Department of Neurology, University of California, San Francisco, CA, USA
| | - Jung Hoon Shin
- Laboratory on Neurobiology of Compulsive Behaviors, National Institute of Alcohol Abuse and Alcoholism, US National Institutes of Health, Bethesda, MD, USA
| | - Feng Liu
- Department of Neurology, University of California, San Francisco, CA, USA
| | - Martin F Adrover
- Laboratory on Neurobiology of Compulsive Behaviors, National Institute of Alcohol Abuse and Alcoholism, US National Institutes of Health, Bethesda, MD, USA
| | - Samuel A Sakhai
- Department of Neurology, University of California, San Francisco, CA, USA
| | - Marcelo F Lopez
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Khanhky Phamluong
- Department of Neurology, University of California, San Francisco, CA, USA
| | - William C Griffin
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Howard C Becker
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA; Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA; RHJ Department of Veterans Affairs Medical Center, Charleston, SC, USA
| | - Kevin J Bender
- Department of Neurology, University of California, San Francisco, CA, USA
| | - Veronica A Alvarez
- Laboratory on Neurobiology of Compulsive Behaviors, National Institute of Alcohol Abuse and Alcoholism, US National Institutes of Health, Bethesda, MD, USA
| | - Dorit Ron
- Department of Neurology, University of California, San Francisco, CA, USA.
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21
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Abstract
Small GTPases are central regulators of many cellular processes. The highly conserved Rap GTPases perform essential functions in the mammalian nervous system during development and in mature neurons. During neocortical development, Rap1 is required to regulate cadherin- and integrin-mediated adhesion. In the adult nervous system Rap1 and Rap2 regulate the maturation and plasticity of dendritic spine and synapses. Although genetic studies have revealed important roles of Rap GTPases in neurons, their regulation by guanine nucleotide exchange factors (GEFs) that activate them and GTPase activating proteins (GAPs) that inactivate them by stimulating their intrinsic GTPase activity is just beginning to be explored in vivo. Here we review how GEFs and GAPs regulate Rap GTPases in the nervous system with a focus on their in vivo function.
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22
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Abstract
Comparisons of DNA from archaic and modern humans show that these groups interbred, and in some cases received an evolutionary advantage from doing so. This process—adaptive introgression—may lead to a faster rate of adaptation than is predicted from models with mutation and selection alone. Within the last couple of years, a series of studies have identified regions of the genome that are likely examples of adaptive introgression. In many cases, once a region was ascertained as being introgressed, commonly used statistics based on both haplotype as well as allele frequency information were employed to test for positive selection. Introgression by itself, however, changes both the haplotype structure and the distribution of allele frequencies, thus confounding traditional tests for detecting positive selection. Therefore, patterns generated by introgression alone may lead to false inferences of positive selection. Here we explore models involving both introgression and positive selection to investigate the behavior of various statistics under adaptive introgression. In particular, we find that the number and allelic frequencies of sites that are uniquely shared between archaic humans and specific present-day populations are particularly useful for detecting adaptive introgression. We then examine the 1000 Genomes dataset to characterize the landscape of uniquely shared archaic alleles in human populations. Finally, we identify regions that were likely subject to adaptive introgression and discuss some of the most promising candidate genes located in these regions.
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Affiliation(s)
- Fernando Racimo
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA
| | - Davide Marnetto
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin, Italy
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23
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Rothe M, Monteiro F, Dietmann P, Kühl SJ. Comparative expression study of sipa family members during early Xenopus laevis development. Dev Genes Evol 2016; 226:369-82. [DOI: 10.1007/s00427-016-0556-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 06/28/2016] [Indexed: 01/20/2023]
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24
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Reim D, Weis TM, Halbedl S, Delling JP, Grabrucker AM, Boeckers TM, Schmeisser MJ. The Shank3 Interaction Partner ProSAPiP1 Regulates Postsynaptic SPAR Levels and the Maturation of Dendritic Spines in Hippocampal Neurons. Front Synaptic Neurosci 2016; 8:13. [PMID: 27252646 PMCID: PMC4877498 DOI: 10.3389/fnsyn.2016.00013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [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: 02/04/2016] [Accepted: 05/10/2016] [Indexed: 11/13/2022] Open
Abstract
The postsynaptic density or PSD is a submembranous compartment containing a wide array of proteins that contribute to both morphology and function of excitatory glutamatergic synapses. In this study, we have analyzed functional aspects of the Fezzin ProSAP-interacting protein 1 (ProSAPiP1), an interaction partner of the well-known PSD proteins Shank3 and SPAR. Using lentiviral-mediated overexpression and knockdown of ProSAPiP1, we found that this protein is dispensable for the formation of both pre- and postsynaptic specializations per se. We further show that ProSAPiP1 regulates SPAR levels at the PSD and the maturation of dendritic spines. In line with previous findings on the ProSAPiP1 homolog PSD-Zip70, we conclude that Fezzins essentially contribute to the maturation of excitatory spine synapses.
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Affiliation(s)
- Dominik Reim
- Institute for Anatomy and Cell Biology, Ulm UniversityUlm, Germany; International Graduate School in Molecular Medicine, Ulm UniversityUlm, Germany
| | - Tobias M Weis
- Institute for Anatomy and Cell Biology, Ulm UniversityUlm, Germany; International Graduate School in Molecular Medicine, Ulm UniversityUlm, Germany
| | - Sonja Halbedl
- Institute for Anatomy and Cell Biology, Ulm UniversityUlm, Germany; International Graduate School in Molecular Medicine, Ulm UniversityUlm, Germany
| | - Jan Philipp Delling
- Institute for Anatomy and Cell Biology, Ulm UniversityUlm, Germany; International Graduate School in Molecular Medicine, Ulm UniversityUlm, Germany
| | - Andreas M Grabrucker
- Institute for Anatomy and Cell Biology, Ulm UniversityUlm, Germany; WG Molecular Analysis of Synaptopathies, Department of Neurology, Neurocenter of Ulm UniversityUlm, Germany
| | | | - Michael J Schmeisser
- Institute for Anatomy and Cell Biology, Ulm UniversityUlm, Germany; Department of Neurology, Ulm UniversityUlm, Germany
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25
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Rothe M, Kanwal N, Dietmann P, Seigfried F, Hempel A, Schütz D, Reim D, Engels R, Linnemann A, Schmeisser MJ, Bockmann J, Kühl M, Boeckers TM, Kühl SJ. An Epha4/Sipa1l3/Wnt pathway regulates eye development and lens maturation. Development 2016; 144:321-333. [DOI: 10.1242/dev.147462] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 12/06/2016] [Indexed: 01/21/2023]
Abstract
The signal-induced proliferation associated family of proteins comprises four members, SIPA1 and SIPA1L1-1L3. Mutations of the human SIPA1L3 gene result in congenital cataracts. In Xenopus, loss of Sipa1l3 function led to a severe eye phenotype that was distinguished by smaller eyes and lenses including lens fiber cell maturation defects. We found a direct interaction between Sipa1l3 and Epha4, building a functional platform for proper ocular development. Epha4 deficiency phenocopied loss of Sipa1l3 and rescue experiments demonstrated that Epha4 acts up-stream of Sipa1l3 during eye development. Both, Sipa1l3 and Epha4 are required for early eye specification. The ocular phenotype, upon loss of either Epha4 or Sipa1l3, was partially mediated by rax. We demonstrated that canonical Wnt signaling is inhibited downstream of Epha4/Sipa1l3 during normal eye development. Depletion of either Sipa1l3 or Epha4 resulted in an up-regulation of axin2 expression, a direct Wnt/β-catenin target gene. In line with this, Sipa1l3 or Epha4 depletion could be rescued by blocking Wnt/β-catenin or activating non-canonical Wnt signaling. We therefore conclude that this pathomechanism prevents proper eye development and maturation of lens fiber cells resulting in congenital cataracts.
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Affiliation(s)
- Melanie Rothe
- Institute of Biochemistry and Molecular Biology, Ulm University, 89081 Ulm, Germany
- International Graduate School in Molecular Medicine Ulm, 89081 Ulm University, Ulm, Germany
| | - Noreen Kanwal
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
- International Graduate School in Molecular Medicine Ulm, 89081 Ulm University, Ulm, Germany
| | - Petra Dietmann
- Institute of Biochemistry and Molecular Biology, Ulm University, 89081 Ulm, Germany
| | - Franziska Seigfried
- Institute of Biochemistry and Molecular Biology, Ulm University, 89081 Ulm, Germany
- International Graduate School in Molecular Medicine Ulm, 89081 Ulm University, Ulm, Germany
| | - Annemarie Hempel
- Institute of Biochemistry and Molecular Biology, Ulm University, 89081 Ulm, Germany
- International Graduate School in Molecular Medicine Ulm, 89081 Ulm University, Ulm, Germany
| | - Desiree Schütz
- Institute of Biochemistry and Molecular Biology, Ulm University, 89081 Ulm, Germany
| | - Dominik Reim
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
- International Graduate School in Molecular Medicine Ulm, 89081 Ulm University, Ulm, Germany
| | - Rebecca Engels
- Institute of Biochemistry and Molecular Biology, Ulm University, 89081 Ulm, Germany
| | - Alexander Linnemann
- Institute of Biochemistry and Molecular Biology, Ulm University, 89081 Ulm, Germany
| | - Michael J. Schmeisser
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
- Department of Neurology, Ulm University, 89081 Ulm, Germany
| | - Juergen Bockmann
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | - Michael Kühl
- Institute of Biochemistry and Molecular Biology, Ulm University, 89081 Ulm, Germany
| | - Tobias M. Boeckers
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | - Susanne J. Kühl
- Institute of Biochemistry and Molecular Biology, Ulm University, 89081 Ulm, Germany
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26
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Dolnik A, Kanwal N, Mackert S, Halbedl S, Proepper C, Bockmann J, Schoen M, Boeckers TM, Kühl SJ, Schmeisser MJ. Sipa1l3/SPAR3 is targeted to postsynaptic specializations and interacts with the Fezzin ProSAPiP1/Lzts3. J Neurochem 2015; 136:28-35. [PMID: 26364583 DOI: 10.1111/jnc.13353] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 08/10/2015] [Accepted: 09/01/2015] [Indexed: 12/01/2022]
Abstract
Rap GTPase-activating proteins (RapGAPs) are essential for synaptic function as they tightly regulate synaptic Rap signaling. Among the most abundant synaptic RapGAPs in brain are the Spine-associated RapGAPs (SPARs) Sipa1l1/SPAR and Sipa1l2/SPAR2, whereas nothing has been reported on Sipa1l3/SPAR3. In this study, we show that Sipa1l3/SPAR3 is conserved across species, has a distinct expression pattern in the developing rat brain and is localized at excitatory postsynapses. We further demonstrate that the Sipa1l3/SPAR3 C-terminus is required for postsynaptic targeting and represents an interaction module for Fezzins such as ProSAPiP1/Lzts3, a binding partner of the postsynaptic scaffold protein Shank3. Taken together, our data imply that Sipa1l3/SPAR3 is a hitherto unknown synaptic RapGAP, which is targeted to postsynaptic specializations and interacts with Fezzins. Spine-associated RapGAPs (SPARs) are essential modulators of synaptic signaling. Our study is the first to characterize the SPAR family member Sipa1l3/SPAR3 in neuronal tissue. We show that Sipa1l3/SPAR3 is conserved across species, has a distinct expression pattern in brain and is localized to excitatory postsynapses via its C-terminus, which represents an interaction module for other postsynaptic proteins including the Fezzin ProSAPiP1/Lzts3.
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Affiliation(s)
- Anna Dolnik
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Noreen Kanwal
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany.,International Graduate School in Molecular Medicine Ulm, IGradU, Ulm University, Ulm, Germany
| | - Sarah Mackert
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany.,International Graduate School in Molecular Medicine Ulm, IGradU, Ulm University, Ulm, Germany
| | - Sonja Halbedl
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany.,International Graduate School in Molecular Medicine Ulm, IGradU, Ulm University, Ulm, Germany
| | | | - Juergen Bockmann
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Michael Schoen
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Tobias M Boeckers
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Susanne J Kühl
- Institute for Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Michael J Schmeisser
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany.,Department of Neurology, Ulm University, Ulm, Germany
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27
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Abstract
Heterotrimeric G-proteins play a fundamentally important role in regulating signal transduction pathways in the kidney. Accessory proteins are being identified as direct binding partners for heterotrimeric G-protein α or βγ subunits to promote more diverse mechanisms by which G-protein signaling is controlled. In some instances, accessory proteins can modulate the signaling magnitude, localization, and duration following the activation of cell membrane-associated receptors. Alternatively, accessory proteins complexed with their G-protein α or βγ subunits can promote non-canonical models of signaling activity within the cell. In this review, we will highlight the expression profile, localization and functional importance of these newly identified accessory proteins to control the function of select G-protein subunits under normal and various disease conditions observed in the kidney.
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Affiliation(s)
- Frank Park
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center Memphis, TN, USA
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28
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Greenlees R, Mihelec M, Yousoof S, Speidel D, Wu SK, Rinkwitz S, Prokudin I, Perveen R, Cheng A, Ma A, Nash B, Gillespie R, Loebel DA, Clayton-Smith J, Lloyd IC, Grigg JR, Tam PP, Yap AS, Becker TS, Black GC, Semina E, Jamieson RV. Mutations inSIPA1L3cause eye defects through disruption of cell polarity and cytoskeleton organization. Hum Mol Genet 2015; 24:5789-804. [DOI: 10.1093/hmg/ddv298] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 07/21/2015] [Indexed: 01/27/2023] Open
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29
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Zhang J, Wang J, Zhou YF, Ren XY, Lin MM, Zhang QQ, Wang YH, Li X. Rich1 negatively regulates the epithelial cell cycle, proliferation and adhesion by CDC42/RAC1-PAK1-Erk1/2 pathway. Cell Signal 2015; 27:1703-12. [PMID: 26004135 DOI: 10.1016/j.cellsig.2015.05.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [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: 04/23/2015] [Revised: 05/07/2015] [Accepted: 05/08/2015] [Indexed: 10/23/2022]
Abstract
Rich1, a previously identified Rho GTPase-activating protein (RhoGAP), was found to have close relationship with Rho GTPase family members in multiple cellular processes in nervous cells and platelets. But the exact role of Rich1 in epithelial cells remains obscure. The present investigation demonstrated that up-regulation of Rich1 could cause S-phase arrest, proliferation inhibition and adhesion decline with F-actin amount decrease in epithelial cells. Further exploration in hepatocyte HL7702 revealed that overexpression of Rich1 could greatly elevate the intrinsic GTPase activities on both of CDC42 and RAC1 by stimulating GTP hydrolysis, which consequently attenuated the activities of the Rho proteins and the phosphorylation level of those in PAK1-ERK1/2 signaling cascade. While the GAP domain deleted Rich1 variant or silence of endogenous Rich1 expression could not result in any of the biological effects. It is indicated that Rich1, completely different from in other types of cells, might act as a crucial upstream negative regulator via its GAP domain in control of epithelial cell cycle, proliferation and focal adhesion through CDC42/RAC1-PAK1-ERK1/2 signaling pathway and F-actin dynamics.
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Affiliation(s)
- Jun Zhang
- Institute of Molecular Medicine and Oncology, Chongqing Medical University, Chongqing 400016, China.
| | - Juan Wang
- Institute of Molecular Medicine and Oncology, Chongqing Medical University, Chongqing 400016, China
| | - Yun-Fei Zhou
- Institute of Molecular Medicine and Oncology, Chongqing Medical University, Chongqing 400016, China
| | - Xue-Yi Ren
- Chongqing Institute for Food and Drug Control, Chongqing 4001121, China
| | - Ming-Ming Lin
- Institute of Molecular Medicine and Oncology, Chongqing Medical University, Chongqing 400016, China
| | - Qian-Qing Zhang
- Institute of Molecular Medicine and Oncology, Chongqing Medical University, Chongqing 400016, China
| | - Yun-Hong Wang
- Institute of Molecular Medicine and Oncology, Chongqing Medical University, Chongqing 400016, China
| | - Xin Li
- Institute of Molecular Medicine and Oncology, Chongqing Medical University, Chongqing 400016, China
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30
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Lenarczyk M, Pressly JD, Arnett J, Regner KR, Park F. Localization and expression profile of Group I and II Activators of G-protein Signaling in the kidney. J Mol Histol 2015; 46:123-36. [PMID: 25533045 DOI: 10.1007/s10735-014-9605-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/15/2014] [Indexed: 10/24/2022]
Abstract
Activators of G-protein Signaling (AGS) are a family of accessory proteins that were discovered as modulators of heterotrimeric G-protein subunits. The primary aim of the present study was to localize Group I and II AGS proteins and determine the renal expression profile using immunohistochemistry and quantitative RT-PCR, respectively, during normal and injured states of the kidney. Group I AGS1 was found to be predominantly localized to the proximal tubule, Group II AGS3 and AGS5 were exclusively localized to the distal tubular segments, and Group II AGS6 was ubiquitously expressed in every nephron segment of the rodent kidney. In rat kidneys following ischemia-reperfusion injury (IRI), Group I AGS1 mRNA was dramatically increased after 24 h by fivefold (P < 0.05), whereas Group II AGS3 and AGS4 mRNA was significantly decreased at the same time point (P < 0.05). No significant change in the transcript levels were detected at other time points for any of the AGS genes between control and IRI groups. In polycystic diseased kidneys, mRNA levels for AGS3, AGS4 and AGS6 was significantly increased (P < 0.05) by 75-80 % in PCK rat kidneys. The identification of Group I and II AGS mRNA and protein in the kidney may provide insight into the potential mechanism of action during normal and varying states of renal disease or injury.
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Bonvicini C, Milanesi E, Pilotto A, Cattane N, Premi E, Archetti S, Padovani A, Gennarelli M, Borroni B. Understanding phenotype variability in frontotemporal lobar degeneration due to granulin mutation. Neurobiol Aging 2014; 35:1206-11. [PMID: 24368088 DOI: 10.1016/j.neurobiolaging.2013.10.097] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 10/05/2013] [Accepted: 10/28/2013] [Indexed: 12/12/2022]
Abstract
Phenotype in patients with granulin (GRN) mutations is unpredictable, ranging from behavioral variant frontotemporal dementia (bvFTD) to agrammatic variant of primary progressive aphasia (avPPA). To date the wide clinical variability of FTLD-GRN remains unexplained. The aim of the study was to identify genetic pathways differentiating phenotypic expression in patients carrying GRN mutations. Patients carrying the same GRNT272SfsX10 mutation were enrolled, a careful clinical assessment was carried out, and the diagnosis of either bvFTD (n = 10, age = 63.9 ± 9.4) or avPPA (n = 6, age = 58.8 ± 4.7) was done. Microarray gene expression analysis on leukocytes was performed. Genes differentially expressed between the groups were validated by real time polymerase chain reaction considering an age-matched healthy controls group (n = 16, age = 58.4 ± 10.7). We further considered a group of FTD with no GRN mutations (GRN-) (n = 21, 13 bvFTD, and 8 avPPA) for comparisons. Real-time polymerase chain reaction (PCR) confirmed a significant decrease in leukocytes mRNA messenger RNA (mRNA) levels of RAP1GAP in bvFTD patients as compared with avPPA (p = 0.049). This finding was specific for patients with GRN mutations, as we did not observe this pattern in FTD GRN-patients (p = 0.99). The alteration of RAP1GAP mRNA levels may explain the clinical variability of GRN-FTLD patients. This is the first report linking a molecular pathway to specific phenotype expression in FTLD-GRN. To understand the clinical relevance of our early results it will be mandatory to extend the observation to other clinical and neuropathological series.
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Abstract
The small GTPase Rap1 contributes to fear learning and cortico-amygdala plasticity by inhibiting glutamate release from cortical neurons, but mechanisms of this inhibition remain unknown. Conversely, L-type calcium channels (LTCCs) become involved in glutamate release after fear learning and LTP induction. Here, we show that Rap1 deletion in mouse primary cortical neurons increases synaptic vesicle exocytosis without altering endocytosis or vesicle pool size in an LTCC-dependent manner. We identify Erk1/2 as the downstream effector of Rap1 and show that its inhibition increases plasma membrane expression of LTCCs near presynaptic terminals. We propose that the Rap1 signaling enables plasticity and fear learning by regulating LTCCs at cortico-amygdala synapses.
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Guibinga GH, Murray F, Barron N, Pandori W, Hrustanovic G. Deficiency of the purine metabolic gene HPRT dysregulates microRNA-17 family cluster and guanine-based cellular functions: a role for EPAC in Lesch-Nyhan syndrome. Hum Mol Genet 2013; 22:4502-15. [PMID: 23804752 DOI: 10.1093/hmg/ddt298] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Lesch-Nyhan syndrome (LNS) is a neurodevelopmental disorder caused by mutations in the gene encoding the purine metabolic enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT). A series of motor, cognitive and neurobehavioral anomalies characterize this disease phenotype, which is still poorly understood. The clinical manifestations of this syndrome are believed to be the consequences of deficiencies in neurodevelopmental pathways that lead to disordered brain function. We have used microRNA array and gene ontology analysis to evaluate the gene expression of differentiating HPRT-deficient human neuron-like cell lines. We set out to identify dysregulated genes implicated in purine-based cellular functions. Our approach was based on the premise that HPRT deficiency affects preeminently the expression and the function of purine-based molecular complexes, such as guanine nucleotide exchange factors (GEFs) and small GTPases. We found that several microRNAs from the miR-17 family cluster and genes encoding GEF are dysregulated in HPRT deficiency. Most notably, our data show that the expression of the exchange protein activated by cAMP (EPAC) is blunted in HPRT-deficient human neuron-like cell lines and fibroblast cells from LNS patients, and is altered in the cortex, striatum and midbrain of HPRT knockout mouse. We also show a marked impairment in the activation of small GTPase RAP1 in the HPRT-deficient cells, as well as differences in cytoskeleton dynamics that lead to increased motility for HPRT-deficient neuron-like cell lines relative to control. We propose that the alterations in EPAC/RAP1 signaling and cell migration in HPRT deficiency are crucial for neuro-developmental events that may contribute to the neurological dysfunctions in LNS.
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Abstract
Rap proteins (Rap1, Rap2a, b, c) are small molecular weight GTPases of the Ras family. Rap G proteins mediate diverse cellular events such as cell adhesion, proliferation, and gene activation through various signaling pathways. Activation of Rap signal is regulated tightly by several specific regulatory proteins including guanine nucleotide exchange factors and GTPase-activating proteins. Beyond cell biological studies, increasing attempts have been made in the past decade to define the roles of Rap signal in specific functions of normal tissue systems as well as in cancer. In the immune and hematopoietic systems, Rap signal plays crucial roles in the development and function of essentially all lineages of lymphocytes and hematopoietic cells, and importantly, deregulated Rap signal may lead to unique pathological conditions depending on the affected cell types, including various types of leukemia and autoimmunity. The phenotypical studies have unveiled novel, even unexpected functional aspects of Rap signal in cells from a variety of tissues, providing potentially important clues for controlling human diseases, including malignancy.
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Affiliation(s)
- Nagahiro Minato
- Department of Immunology and Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan. :
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Abstract
The functional significance of decreased RAP1GAP protein expression in human tumors is unclear. To identify targets of RAP1GAP downregulation in the thyroid gland, RAP1 and RAP2 protein expression in human thyroid cells and in primary thyroid tumors were analyzed. RAP1GAP and RAP2 were co-expressed in normal thyroid follicular cells. Intriguingly, RAP1 was not detected in normal thyroid cells, although it was detected in papillary thyroid carcinomas, which also expressed RAP2. Both RAP proteins were detected at the membrane in papillary thyroid tumors, suggesting that they are activated when RAP1GAP is downregulated. To explore the functional significance of RAP1GAP depletion, RAP1GAP was transiently expressed at the lowest level that is sufficient to block endogenous RAP2 activity in papillary and anaplastic thyroid carcinoma cell lines. RAP1GAP impaired the ability of cells to spread and migrate on collagen. Although RAP1GAP had no effect on protein tyrosine phosphorylation in growing cells, RAP1GAP impaired phosphorylation of focal adhesion kinase and paxillin at sites phosphorylated by SRC in cells acutely plated on collagen. SRC activity was increased in suspended cells, where it was inhibited by RAP1GAP. Inhibition of SRC kinase activity impaired cell spreading and motility. These findings identify SRC as a target of RAP1GAP depletion and suggest that the downregulation of RAP1GAP in thyroid tumors enhances SRC-dependent signals that regulate cellular architecture and motility.
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Affiliation(s)
- Xiaoyun Dong
- Department of Pharmacology - Head and Neck Surgery, School of Medicine, University of Pennsylvania, 421 Curie Boulevard, BRB II/III, Philadelphia, PA 19104, USA
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Sadrian B, Cheng TW, Shull O, Gong Q. Rap1gap2 regulates axon outgrowth in olfactory sensory neurons. Mol Cell Neurosci 2012; 50:272-82. [PMID: 22732430 DOI: 10.1016/j.mcn.2012.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 06/13/2012] [Accepted: 06/14/2012] [Indexed: 12/30/2022] Open
Abstract
Olfactory sensory neurons (OSNs) extend their axons from the nasal epithelium to their odorant receptor-dependent locations in the olfactory bulb. Previous studies have identified several membrane proteins along the projection pathway, and on OSN axons themselves, which regulate this process; however, little is known about the signaling mechanisms through which these factors act. We have identified and characterized Rap1gap2, a novel small GTPase regulator, in OSNs during early postnatal mouse development. Rap1gap2 overexpression limits neurite outgrowth and branching in Neuro-2a cells, and counteracts Rap1-induced augmentation of neurite outgrowth. Rap1gap2 expression is developmentally regulated within OSNs, with high expression in early postnatal stages that ultimately drops to undetectable levels by adulthood. This temporal pattern coincides with an early postnatal plastic period of OSN innervation refinement at the OB glomerular layer. Rap1gap2 stunts OSN axon outgrowth when overexpressed in vitro, while knock-down of Rap1gap2 transcript results in a significant increase in axon length. These results indicate an important role of Rap1gap2 in OSN axon growth dynamics during early postnatal development.
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Affiliation(s)
- Benjamin Sadrian
- Department of Cell Biology and Human Anatomy, University of California, Davis, School of Medicine, Davis, CA 95616, USA.
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Abstract
The attachment of stem cells to specialized functional niches instructs stem cell maintenance, with loss of adhesion associated with differentiation driven by cell-intrinsic programs. Id transcription factors are now shown to link cell-intrinsic maintenance programs and extrinsic cues by promoting adhesion of neural stem cells to the niche.
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Abstract
Beyond the core triad of receptor, Gαβγ and effector, there are multiple accessory proteins that provide alternative modes of signal input and regulatory adaptability to G-protein signalling systems. Such accessory proteins may segregate a signalling complex to microdomains of the cell, regulate the basal activity, efficiency and specificity of signal propagation and/or serve as alternative binding partners for Gα or Gβγ independent of the classical heterotrimeric Gαβγ complex. The latter concept led to the postulate that Gα and Gβγ regulate intracellular events distinct from their role as transducers for cell surface seven-transmembrane span receptors. One general class of such accessory proteins is defined by AGS proteins or activators of G-protein signalling that refer to mammalian cDNAs identified in a specific yeast-based functional screen. The discovery of AGS proteins and related entities revealed a number of unexpected mechanisms for regulation of G-protein signalling systems and expanded functional roles for this important signalling system.
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Affiliation(s)
- J B Blumer
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, 29425, USA
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Chen Y, Yuanxiang P, Knöpfel T, Thomas U, Behnisch T. Hippocampal LTP triggers proteasome-mediated SPAR degradation in CA1 neurons. Synapse 2011; 66:142-50. [DOI: 10.1002/syn.20994] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 09/28/2011] [Indexed: 12/30/2022]
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Abstract
The significance of the widespread downregulation of Rap1GAP in human tumors is unknown. In previous studies we demonstrated that silencing Rap1GAP expression in human colon cancer cells resulted in sustained increases in Rap activity, enhanced spreading on collagen and the weakening of cell-cell contacts. The latter finding was unexpected based on the role of Rap1 in strengthening cell-cell adhesion and reports that Rap1GAP impairs cell-cell adhesion. We now show that Rap1GAP is a more effective inhibitor of cell-matrix compared to cell-cell adhesion. Overexpression of Rap1GAP in human colon cancer cells impaired Rap2 activity and the ability of cells to spread and migrate on collagen IV. Under the same conditions, Rap1GAP had no effect on cell-cell adhesion. Overexpression of Rap1GAP did not enhance the dissociation of cell aggregates nor did it impair the accumulation of β-catenin and E-cadherin at cell-cell contacts. To further explore the role of Rap1GAP in the regulation of cell-cell adhesion, Rap1GAP was overexpressed in non-transformed thyroid epithelial cells. Although the formation of cell-cell contacts required Rap1, overexpression of Rap1GAP did not impair cell-cell adhesion. These data indicate that transient, modest expression of Rap1GAP is compatible with cell-cell adhesion and that the role of Rap1GAP in the regulation of cell-cell adhesion may be more complex than is currently appreciated.
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Affiliation(s)
- Lisa A Vuchak
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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