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Kumar S, Abbas MM, Govindappa ST, Muthane UB, Behari M, Pandey S, Juyal RC, Thelma BK. Compound heterozygous variants in Wiskott-Aldrich syndrome like (WASL) gene segregating in a family with early onset Parkinson's disease. Parkinsonism Relat Disord 2021; 84:61-67. [PMID: 33571872 DOI: 10.1016/j.parkreldis.2021.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 01/19/2021] [Accepted: 02/01/2021] [Indexed: 10/22/2022]
Abstract
BACKGROUND Knowledge of genetic determinants in Parkinson's disease is still limited. Familial forms of the disease continue to provide a rich resource to capture the genetic spectrum in disease pathogenesis, and this approach is exploited in this study. METHODS Informative members from a three-generation family of Indian ethnicity manifesting a likely autosomal recessive mode of inheritance of Parkinson's disease were used for whole exome sequencing. Variant data analysis and in vitro functional characterisation of variant(s) segregating with the phenotype were carried out in HEK-293 and SH-SY5Y cells using gene constructs of interest. RESULTS Two compound heterozygous variants, a rare missense (c.1139C > T:p.P380L) and a novel splice variant (c.1456 + 2 delTAGA, intron10) in Wiskott-Aldrich syndrome like gene (WASL, 7q31), both predicted to be deleterious were shared among the proband and two affected siblings. WASL, a gene not previously linked to a human Mendelian disorder is known to regulate actin polymerisation via Arp2/3 complex. Based on exon trapping assay using pSPL3 vector in HEK-293 cells, the splice variant showed skipping of exon10. Characterisation of the missense variant in SH-SY5Y cells demonstrated: i) significant alterations in neurite length and number; ii) decreased reactive oxygen species tolerance in mutation carrying cells on Tetrabutylphosphonium hydroxide induction and iii) increase in alpha-synuclein protein. Screening for WASL variants in two independent PD cohorts identified four individuals with heterozygous but none with biallelic variants. CONCLUSION WASL, with demonstrated functional relevance in neurons may be yet another strong candidate gene for autosomal recessive PD encouraging assessment of its contribution across populations.
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Affiliation(s)
- Sumeet Kumar
- Department of Genetics, University of Delhi South Campus, New Delhi, 110021, India
| | - Masoom M Abbas
- Parkinson's and Aging Research Foundation, Bangalore, India
| | | | - Uday B Muthane
- Parkinson's and Aging Research Foundation, Bangalore, India
| | - Madhuri Behari
- All India Institute of Medical Sciences, New Delhi, India
| | - Sanjay Pandey
- Department of Neurology, Govind Ballabh Pant Postgraduate Institute of Medical Education and Research, New Delhi, India
| | | | - B K Thelma
- Department of Genetics, University of Delhi South Campus, New Delhi, 110021, India.
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2
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Hermann C, Lang S, Popp T, Hafner S, Steinritz D, Rump A, Port M, Eder S. Bardoxolone-Methyl (CDDO-Me) Impairs Tumor Growth and Induces Radiosensitization of Oral Squamous Cell Carcinoma Cells. Front Pharmacol 2021; 11:607580. [PMID: 33584286 PMCID: PMC7878525 DOI: 10.3389/fphar.2020.607580] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/09/2020] [Indexed: 12/19/2022] Open
Abstract
Radiotherapy represents a common treatment strategy for patients suffering from oral squamous cell carcinoma (OSCC). However, application of radiotherapy is immanently limited by radio-sensitivity of normal tissue surrounding the tumor sites. In this study, we used normal human epithelial keratinocytes (NHEK) and OSCC cells (Cal-27) as models to investigate radio-modulating and anti-tumor effects of the synthetic triterpenoid 2-cyano-3,12-dioxooleana-1,9,-dien-28-oic acid methyl ester (CDDO-Me). Nanomolar CDDO-Me significantly reduced OSCC tumor xenograft-growth in-ovo applying the chick chorioallantoic membrane (CAM) assay. In the presence of CDDO-Me reactive oxygen species (ROS) were found to be reduced in NHEK when applying radiation doses of 8 Gy, whereas ROS levels in OSCC cells rose significantly even without radiation. In parallel, CDDO-Me was shown to enhance metabolic activity in malignant cells only as indicated by significant accumulation of reducing equivalents NADPH/NADH. Furthermore, antioxidative heme oxygenase-1 (HO-1) levels were only enhanced in NHEK and not in the OSCC cell line, as shown by immunoblotting. Clonogenic survival was left unchanged by CDDO-Me treatment in NHEK but revealed to be abolished almost completely in OSCC cells. Our results indicate anti-cancer and radio-sensitizing effects of CDDO-Me treatment in OSCC cells, whereas nanomolar CDDO-Me failed to provoke clear detrimental consequences in non-malignant keratinocytes. We conclude, that the observed differential aftermath of CDDO-Me treatment in malignant OSCC and non-malignant skin cells may be utilized to broaden the therapeutic range of clinical radiotherapy.
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Affiliation(s)
| | - Simon Lang
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Tanja Popp
- Bundeswehr Institute of Radiobiology, Munich, Germany
| | - Susanne Hafner
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, University of Ulm, Ulm, Germany
| | - Dirk Steinritz
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Alexis Rump
- Bundeswehr Institute of Radiobiology, Munich, Germany
| | - Matthias Port
- Bundeswehr Institute of Radiobiology, Munich, Germany
| | - Stefan Eder
- Bundeswehr Institute of Radiobiology, Munich, Germany.,Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, Inner City Clinic, University Hospital of Munich (LMU), Munich, Germany
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3
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Cheng Y, Sun M, Wang F, Geng X, Wang F. Identification of Hub Genes Related to Alzheimer's Disease and Major Depressive Disorder. Am J Alzheimers Dis Other Demen 2021; 36:15333175211046123. [PMID: 34732058 PMCID: PMC10695082 DOI: 10.1177/15333175211046123] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BackgroundAlthough many studies reported a close relationship between depression and Alzheimer's disease (AD), the underlying pathophysiological mechanism remains unclear. The present study aimed to investigate the mechanism of AD and major depressive disorder (MDD). Method: The datasets were downloaded from the Gene Expression Omnibus. After screening differentially expressed genes (DEGs), gene ontology and pathway analysis were performed and protein-protein interaction, TF-target gene, and miRNA-target gene networks were established. Results: 171 DEGs of AD-related datasets and 79 DEGs shared by AD and MDD were detected. Functional analysis revealed that AD and MDD common genes were significantly enriched in circadian entrainment and long-term depression signaling pathways. Five hub genes were identified after construction of networks and validation of hub gene signatures. In conclusion, DYNC1H1, MAPRE3, TTBK2, ITGB1, and WASL may be potential targets for the diagnosis and treatment of AD and MDD.
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Affiliation(s)
- Yajing Cheng
- Department of Neurology, General Hospital, Tianjin Medical University, Tianjin, China
| | - Meiyue Sun
- Department of Neurology, General Hospital, Tianjin Medical University, Tianjin, China
| | - Feng Wang
- Department of Genetics, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Xin Geng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
- Tianjin Key Laboratory of Cellular and Molecular Immunology, Key Laboratory of Immune Microenvironment and Disease of Ministry of Education, Tianjin Medical University, Tianjin, China
- Tianjin Key Laboratory of Medical Epigenetics, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Fei Wang
- Department of Neurology, General Hospital, Tianjin Medical University, Tianjin, China
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4
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Kähler J, Hafner S, Popp T, Hermann C, Rump A, Port M, Steinestel K, Eder S. Heterogeneous nuclear ribonucleoprotein K is overexpressed and contributes to radioresistance irrespective of HPV status in head and neck squamous cell carcinoma. Int J Mol Med 2020; 46:1733-1742. [PMID: 32901844 PMCID: PMC7521550 DOI: 10.3892/ijmm.2020.4718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 08/17/2020] [Indexed: 12/24/2022] Open
Abstract
Radiotherapy is a major treatment option for head and neck squamous cell carcinoma (HNSCC). However, the success of radiotherapy is limited by tumor cell resistance to ionizing radiation (IR). Clinical studies have demonstrated an overall improved prognosis and higher susceptibility to radiotherapy of high‑risk human papillomavirus (HPV)‑associated HNSCC compared with classic HNSCC, as well as worse overall survival for male HNSCC patients. Overexpression of heterogeneous nuclear ribonucleoprotein (hnRNP) K has been associated with resistance to radiotherapy in melanoma and colorectal carcinoma. The aim of the present study was to analyze the impact of hnRNP K expression on the aggressiveness and radioresistance of HNSCC with respect to patient sex and HPV status. Immunohistochemical staining of HNSCC tissue specimens revealed elevated hnRNP K levels compared with those in the non‑neoplastic epithelium. Cytoplasmic hnRNP K accumulation was associated with advanced tumor stage and male sex. Exposure of HNSCC cells to IR was followed by rapid upregulation of hnRNP K at the protein level, along with re‑localization from the tumor cell nucleus to the cytoplasm. siRNA‑based knockdown of hnRNP K induced apoptosis and abolished tumor formation after xenotransplantation of HNSCC cells onto the chick egg chorioallantoic membrane (CAM). The observed effects were independent of the respective HPV status of the cell lines. These results indicated a tumorigenic and anti‑apoptotic role of hnRNP K in HNSCC, which appeared to be enhanced in male patients and contributed to the radioresistance of these tumors. However, the radioprotective effects of hnRNP K were found to be independent of the tumor's HPV status.
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Affiliation(s)
- Justus Kähler
- Bundeswehr Institute of Radiobiology, D‑80937 Munich, Germany
| | - Susanne Hafner
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, University of Ulm, D‑89081 Ulm, Germany
| | - Tanja Popp
- Bundeswehr Institute of Radiobiology, D‑80937 Munich, Germany
| | | | - Alexis Rump
- Bundeswehr Institute of Radiobiology, D‑80937 Munich, Germany
| | - Matthias Port
- Bundeswehr Institute of Radiobiology, D‑80937 Munich, Germany
| | - Konrad Steinestel
- Institute of Pathology and Molecular Pathology, Bundeswehrkrankenhaus Ulm, D‑89081 Ulm, Germany
| | - Stefan Eder
- Bundeswehr Institute of Radiobiology, D‑80937 Munich, Germany
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5
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Steinestel K, Trautmann M, Jansen EP, Dirksen U, Rehkämper J, Mikesch JH, Gerke JS, Orth MF, Sannino G, Arteaga MF, Rossig C, Wardelmann E, Grünewald TGP, Hartmann W. Focal adhesion kinase confers pro-migratory and antiapoptotic properties and is a potential therapeutic target in Ewing sarcoma. Mol Oncol 2019; 14:248-260. [PMID: 31811703 PMCID: PMC6998388 DOI: 10.1002/1878-0261.12610] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 11/10/2019] [Accepted: 12/05/2019] [Indexed: 12/21/2022] Open
Abstract
Oncogenesis of Ewing sarcoma (EwS), the second most common malignant bone tumor of childhood and adolescence, is dependent on the expression of chimeric EWSR1‐ETS fusion oncogenes, most often EWSR1‐FLI1 (E/F). E/F expression leads to dysregulation of focal adhesions (FAs) enhancing the migratory capacity of EwS cells. Here, we show that, in EwS cell lines and tissue samples, focal adhesion kinase (FAK) is expressed and phosphorylated at Y397 in an E/F‐dependent way involving Ezrin. Employing different EwS cell lines as in vitro models, we found that key malignant properties of E/F are mediated via substrate‐independent autophosphorylation of FAK on Y397. This phosphorylation results in enhanced FA formation, Rho‐dependent cell migration, and impaired caspase‐3‐mediated apoptosis in vitro. Conversely, treatment with the FAK inhibitor 15 (1,2,4,5‐benzenetetraamine tetrahydrochloride (Y15) enhanced caspase‐mediated apoptosis and EwS cell migration, independent from the respective EWSR1‐ETS fusion type, mimicking an anoikis‐like phenotype and paralleling the effects of FAK siRNA knockdown. Our findings were confirmed in vivo using an avian chorioallantoic membrane model and provide a first rationale for the therapeutic use of FAK inhibitors to impair metastatic dissemination of EwS.
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Affiliation(s)
- Konrad Steinestel
- Gerhard Domagk Institute of Pathology, University Hospital Münster, Germany.,Institute of Pathology and Molecular Pathology, Bundeswehrkrankenhaus Ulm, Germany
| | - Marcel Trautmann
- Gerhard Domagk Institute of Pathology, University Hospital Münster, Germany.,Division of Translational Pathology, Gerhard-Domagk-Institute of Pathology, University Hospital Münster, Germany
| | - Esther-Pia Jansen
- Gerhard Domagk Institute of Pathology, University Hospital Münster, Germany
| | - Uta Dirksen
- Pediatrics III, West German Cancer Centre, University Hospital Essen, Germany
| | - Jan Rehkämper
- Institute of Pathology, University Hospital Cologne, Germany
| | | | - Julia S Gerke
- Max Eder Research Group for Pediatric Sarcoma Biology, Institute of Pathology, Faculty of Medicine, LMU Munich, Germany
| | - Martin F Orth
- Max Eder Research Group for Pediatric Sarcoma Biology, Institute of Pathology, Faculty of Medicine, LMU Munich, Germany
| | - Giuseppina Sannino
- Max Eder Research Group for Pediatric Sarcoma Biology, Institute of Pathology, Faculty of Medicine, LMU Munich, Germany
| | | | - Claudia Rossig
- Department of Pediatric Hematology and Oncology, University Children's Hospital Münster, Germany
| | - Eva Wardelmann
- Gerhard Domagk Institute of Pathology, University Hospital Münster, Germany
| | - Thomas G P Grünewald
- Max Eder Research Group for Pediatric Sarcoma Biology, Institute of Pathology, Faculty of Medicine, LMU Munich, Germany.,German Cancer Consortium (DKTK), Partner Site Munich, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany.,Institute of Pathology, Faculty of Medicine, LMU Munich, Germany
| | - Wolfgang Hartmann
- Gerhard Domagk Institute of Pathology, University Hospital Münster, Germany.,Division of Translational Pathology, Gerhard-Domagk-Institute of Pathology, University Hospital Münster, Germany
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6
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Cruz D, Pinto R, Freitas-Silva M, Nunes JP, Medeiros R. GWAS contribution to atrial fibrillation and atrial fibrillation-related stroke: pathophysiological implications. Pharmacogenomics 2019; 20:765-780. [PMID: 31368859 DOI: 10.2217/pgs-2019-0054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Atrial fibrillation (AF) and stroke are included in a group of complex traits that have been approached regarding of their study by susceptibility genetic determinants. Since 2007, several genome-wide association studies (GWAS) aiming to identify genetic variants modulating AF risk have been conducted. Thus, 11 GWAS have identified 26 SNPs (p < 5 × 10-2), of which 19 reached genome-wide significance (p < 5 × 10-8). From those variants, seven were also associated with cardioembolic stroke and three reached genome-wide significance in stroke GWAS. These associations may shed a light on putative shared etiologic mechanisms between AF and cardioembolic stroke. Additionally, some of these identified variants have been incorporated in genetic risk scores in order to elucidate new approaches of stroke prediction, prevention and treatment.
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Affiliation(s)
- Diana Cruz
- Molecular Oncology & Viral Pathology Group-Research Center, Portuguese Institute of Oncology, Edifício Laboratórios. 4° piso, Rua Dr António Bernardino de Almeida, 4200-4072 Porto, Portugal.,FMUP, Faculty of Medicine, Porto University, Alameda Prof Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Ricardo Pinto
- Molecular Oncology & Viral Pathology Group-Research Center, Portuguese Institute of Oncology, Edifício Laboratórios. 4° piso, Rua Dr António Bernardino de Almeida, 4200-4072 Porto, Portugal
| | - Margarida Freitas-Silva
- FMUP, Faculty of Medicine, Porto University, Alameda Prof Hernâni Monteiro, 4200-319 Porto, Portugal.,Department of Medicine, Centro Hospitalar São João, Porto, Portugal
| | - José Pedro Nunes
- FMUP, Faculty of Medicine, Porto University, Alameda Prof Hernâni Monteiro, 4200-319 Porto, Portugal.,Department of Medicine, Centro Hospitalar São João, Porto, Portugal
| | - Rui Medeiros
- Molecular Oncology & Viral Pathology Group-Research Center, Portuguese Institute of Oncology, Edifício Laboratórios. 4° piso, Rua Dr António Bernardino de Almeida, 4200-4072 Porto, Portugal.,FMUP, Faculty of Medicine, Porto University, Alameda Prof Hernâni Monteiro, 4200-319 Porto, Portugal.,Research Department, Portuguese League Against Cancer (NRNorte), Estrada Interior da Circunvalação, 6657, 4200-172 Porto, Portugal.,CEBIMED, Faculty of Health Sciences, Fernando Pessoa University, Praça 9 de Abril, 349, 4249-004 Porto, Portugal
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7
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[Regulator proteins of actin dynamics as possible targets of antineoplastic therapies]. DER PATHOLOGE 2018; 39:225-230. [PMID: 30229281 DOI: 10.1007/s00292-018-0495-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
BACKGROUND The ability of tumor cells to leave the primary tumor is prerequisite for metastatic spread. In previous studies, we identified regulator proteins of actin reorganization with essential functions in both synaptogenesis and tumor cell migration. OBJECTIVE The aim of the studies summarized in this article is to identify signaling pathways associated with actin-related proteins that might represent potential molecular targets for antiinvasive and/or antineoplastic therapies. MATERIALS AND METHODS We used immunohistochemical analyses of protein expression as well as in vitro techniques (cell culture, fluorescence microscopy, RNAi-based knockdown of protein expression, protein biochemistry and in vivo animal experiment substitutes). RESULTS We show that phosphorylation of Abelson interactor 1 (Abi1) is essential for the adhesion and invasion of colorectal carcinoma cells and might be targeted by the tyrosine kinase inhibitor STI571/Glivec®. HnRNP K, a protein interaction partner of Abi1, is upregulated in malignant melanoma in response to ionizing radiation; this upregulation is impaired upon application of the MEK inhibitor PD98059, enhancing radiosensivity of melanoma. Edelfosin, an alkyl-lipid blocker of the Abi1 interaction partner SK3, inhibits invasion of urothelial carcinoma cells. CONCLUSION The studies summarized in this overview confirm a central role for the investigated proteins in tumor cell invasion and resistance to antineoplastic therapies and identify possible molecular targets for novel therapeutic compounds.
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Baseline MAPK signaling activity confers intrinsic radioresistance to KRAS-mutant colorectal carcinoma cells by rapid upregulation of heterogeneous nuclear ribonucleoprotein K (hnRNP K). Cancer Lett 2017; 385:160-167. [DOI: 10.1016/j.canlet.2016.10.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 10/17/2016] [Accepted: 10/18/2016] [Indexed: 12/13/2022]
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9
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Garcia EL, Wen Y, Praveen K, Matera AG. Transcriptomic comparison of Drosophila snRNP biogenesis mutants reveals mutant-specific changes in pre-mRNA processing: implications for spinal muscular atrophy. RNA (NEW YORK, N.Y.) 2016; 22:1215-1227. [PMID: 27268418 PMCID: PMC4931114 DOI: 10.1261/rna.057208.116] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 05/12/2016] [Indexed: 06/06/2023]
Abstract
Survival motor neuron (SMN) functions in the assembly of spliceosomal small nuclear ribonucleoproteins (snRNPs) that catalyze pre-mRNA splicing. Here, we used disruptions in Smn and two additional snRNP biogenesis genes, Phax and Ars2, to classify RNA processing differences as snRNP-dependent or gene-specific in Drosophila Phax and Smn mutants exhibited comparable reductions in snRNAs, and comparison of their transcriptomes uncovered shared sets of RNA processing changes. In contrast, Ars2 mutants displayed only small decreases in snRNA levels, and RNA processing changes in these mutants were generally distinct from those identified in Phax and Smn animals. Instead, RNA processing changes in Ars2 mutants support the known interaction of Ars2 protein with the cap-binding complex, as splicing changes showed a clear bias toward the first intron. Bypassing disruptions in snRNP biogenesis, direct knockdown of spliceosomal proteins caused similar changes in the splicing of snRNP-dependent events. However, these snRNP-dependent events were largely unaltered in three Smn mutants expressing missense mutations that were originally identified in human spinal muscular atrophy (SMA) patients. Hence, findings here clarify the contributions of Phax, Smn, and Ars2 to snRNP biogenesis in Drosophila, and loss-of-function mutants for these proteins reveal differences that help disentangle cause and effect in SMA model flies.
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Affiliation(s)
- Eric L Garcia
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Ying Wen
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Kavita Praveen
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - A Gregory Matera
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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Martin S, Lazzarini M, Dullin C, Balakrishnan S, Gomes FV, Ninkovic M, El Hady A, Pardo LA, Stühmer W, Del-Bel E. SK3 Channel Overexpression in Mice Causes Hippocampal Shrinkage Associated with Cognitive Impairments. Mol Neurobiol 2016; 54:1078-1091. [PMID: 26803493 PMCID: PMC5310555 DOI: 10.1007/s12035-015-9680-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 12/23/2015] [Indexed: 12/11/2022]
Abstract
The dysfunction of the small-conductance calcium-activated K+ channel SK3 has been described as one of the factors responsible for the progress of psychoneurological diseases, but the molecular basis of this is largely unknown. This report reveals through use of immunohistochemistry and computational tomography that long-term increased expression of the SK3 small-conductance calcium-activated potassium channel (SK3-T/T) in mice induces a notable bilateral reduction of the hippocampal area (more than 50 %). Histological analysis showed that SK3-T/T mice have cellular disarrangements and neuron discontinuities in the hippocampal formation CA1 and CA3 neuronal layer. SK3 overexpression resulted in cognitive loss as determined by the object recognition test. Electrophysiological examination of hippocampal slices revealed that SK3 channel overexpression induced deficiency of long-term potentiation in hippocampal microcircuits. In association with these results, there were changes at the mRNA levels of some genes involved in Alzheimer’s disease and/or linked to schizophrenia, epilepsy, and autism. Taken together, these features suggest that augmenting the function of SK3 ion channel in mice may present a unique opportunity to investigate the neural basis of central nervous system dysfunctions associated with schizophrenia, Alzheimer’s disease, or other neuropsychiatric/neurodegenerative disorders in this model system. As a more detailed understanding of the role of the SK3 channel in brain disorders is limited by the lack of specific SK3 antagonists and agonists, the results observed in this study are of significant interest; they suggest a new approach for the development of neuroprotective strategies in neuropsychiatric/neurodegenerative diseases with SK3 representing a potential drug target.
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Affiliation(s)
- Sabine Martin
- Department of Molecular Biology of Neuronal Signals, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3, 37075, Göttingen, Germany
- Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Marcio Lazzarini
- Department of Molecular Biology of Neuronal Signals, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3, 37075, Göttingen, Germany
| | - Christian Dullin
- Department of Diagnostic and Interventional Radiology, Georg-August University Medical Center, 37075, Göttingen, Germany
| | - Saju Balakrishnan
- Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
- Department of Neuro- and Sensory Physiology, Georg-August University Medical Center, 37073, Göttingen, Germany
| | - Felipe V Gomes
- Department of Pharmacology, Medical School of Ribeirão Preto, University of São Paulo, 14040-900, Ribeirão Preto, Brazil
| | - Milena Ninkovic
- Department of Neurosurgery, Georg-August University Medical Center, 37075, Göttingen, Germany
| | - Ahmed El Hady
- Department of Molecular Biology of Neuronal Signals, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3, 37075, Göttingen, Germany
- Bernstein Focus for Neurotechnology and Bernstein Center for Computational Neuroscience, Göttingen, Germany
- Theoretical Neurophysics, Department of Non-linear Dynamics, Max Planck Institute for Dynamics and Self-Organization, 37077, Göttingen, Germany
- The Interdisciplinary Collaborative Research Center 889 "Cellular Mechanisms of Sensory Processing", Göttingen, Germany
| | - Luis A Pardo
- Oncophysiology Group, Max Planck Institute of Experimental Medicine, 37075, Göttingen, Germany
| | - Walter Stühmer
- Department of Molecular Biology of Neuronal Signals, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3, 37075, Göttingen, Germany.
- Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.
- Bernstein Focus for Neurotechnology and Bernstein Center for Computational Neuroscience, Göttingen, Germany.
| | - Elaine Del-Bel
- Department of Morphology, Physiology and Pathology, CNPQ Research 1B (Biophysics, Biochemistry, Pharmacology and Neuroscience), University of São Paulo Dental School of Ribeirão Preto, Avenida do Café 3400, 14040-904, Ribeirão Preto, Brazil.
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The small conductance calcium-activated potassium channel 3 (SK3) is a molecular target for Edelfosine to reduce the invasive potential of urothelial carcinoma cells. Tumour Biol 2015; 37:6275-83. [PMID: 26619845 DOI: 10.1007/s13277-015-4509-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/25/2015] [Indexed: 02/05/2023] Open
Abstract
Metastasis is the survival-determining factor in urothelial carcinoma (UC) of the urinary bladder. The small conductance calcium-activated potassium channel 3 (SK3) enhances tumor cell invasion in breast cancer and malignant melanoma. Since Edelfosine, a glycerophospholipid with antitumoral properties, effectively inhibits SK3 channel activity, our goal was to evaluate SK3 as a potential molecular target to inhibit the gain of an invasive phenotype in UC. SK3 protein expression was analyzed in 208 tissue samples and UC cell lines. Effects of Edelfosine on SK3 expression and intracellular calcium levels as well as on cell morphology, cell survival and proliferation were assessed using immunoblotting, potentiometric fluorescence microscopy, and clonogenic/cell survival assay; furthermore, we analyzed the effect of Edelfosine and SK3 RNAi knockdown on tumor cell migration and invasion in vitro and in vivo. We found that SK3 is strongly expressed in muscle-invasive UC and in the RT112 cellular tumor model. Higher concentrations of Edelfosine have a strong antitumoral effect on UC cells, while 1 μM effectively inhibits migration/invasion of UC cells in vitro and in vivo comparable to the SK3 knockdown phenotype. Taken together, our results show strong expression of SK3 in muscle-invasive UC, consistent with the postulated role of the protein in tumor cell invasion. Edelfosine is able to effectively inhibit migration and invasion of UC cells in vitro and in vivo in an SK3-dependent way, pointing towards a possible role for Edelfosine as an antiinvasive drug to effectively inhibit UC cell invasion and metastasis.
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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] [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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13
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Regulators of Actin Dynamics in Gastrointestinal Tract Tumors. Gastroenterol Res Pract 2015; 2015:930157. [PMID: 26345720 PMCID: PMC4539459 DOI: 10.1155/2015/930157] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Revised: 07/09/2015] [Accepted: 07/21/2015] [Indexed: 02/07/2023] Open
Abstract
Reorganization of the actin cytoskeleton underlies cell migration in a wide variety of physiological and pathological processes, such as embryonic development, wound healing, and tumor cell invasion. It has been shown that actin assembly and disassembly are precisely regulated by intracellular signaling cascades that respond to changes in the cell microenvironment, ligand binding to surface receptors, or oncogenic transformation of the cell. Actin-nucleating and actin-depolymerizing (ANFs/ADFs) and nucleation-promoting factors (NPFs) regulate cytoskeletal dynamics at the leading edge of migrating cells, thereby modulating cell shape; these proteins facilitate cellular movement and mediate degradation of the surrounding extracellular matrix by secretion of lytic proteases, thus eliminating barriers for tumor cell invasion. Accordingly, expression and activity of these actin-binding proteins have been linked to enhanced metastasis and poor prognosis in a variety of malignancies. In this review, we will summarize what is known about expression patterns and the functional role of actin regulators in gastrointestinal tumors and evaluate first pharmacological approaches to prevent invasion and metastatic dissemination of malignant cells.
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Steinestel K, Gläsle F, Brüderlein S, Steinestel J, Pröpper C, Möller P. [Abelson interactor 1 (Abi1) in colorectal cancer. From synaptic plasticity to tumor cell migration]. DER PATHOLOGE 2014; 34 Suppl 2:189-94. [PMID: 24196611 DOI: 10.1007/s00292-013-1810-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND Invasion and metastatic dissemination of tumor cells defines the prognosis of patients with colorectal cancer (CRC). The Abelson interactor 1 (Abi1), a 65 kD substrate of the eponymous Abelson tyrosine kinase, interacts with phosphatidylinositol-3-kinase (PI3K) and heterogeneous nuclear ribonucleoprotein K (hnRNP K) and is a key regulator of cytoskeletal reorganization during synaptic maturation and cellular migration. AIM The aim of this study was the analysis of Abi1 expression patterns and to elucidate the role in cytoskeletal reorganization in colorectal carcinoma cells. MATERIAL AND METHODS The methods used in this study were immunohistochemistry; immunofluorescence microscopy; liposomal transfection and protein analysis by Western blotting. RESULTS The results showed that Abi1 is expressed at the invasive front of colorectal carcinomas and localizes to the leading edge of lamellipodia in cultured colorectal carcinoma cells. A phosphorylated isoform of Abi1 that stains positively in these microcompartments disappears after treatment with the tyrosine kinase inhibitor STI571 (Glivec®). The RNA interference (RNAi) approach knockdown of Abi1 as well as treatment with STI571 induce a shift in cellular morphology from broad lamellipodia-like to thin filopodia-like cellular protrusions. DISCUSSION The initial results support a central role for phosphorylated Abi1 in the formation of lamellipodia-like cellular protrusions as a prerequisite for cellular migration of colorectal carcinoma cells. As phosphorylation of Abi1 could be pharmaceutically targeted with STI571, this indicates a possible therapeutic option to prevent the gain of a metastatic phenotype in colorectal cancer. This possibility will be further evaluated in ongoing research.
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Affiliation(s)
- K Steinestel
- Institut für Radiobiologie der Bundeswehr, Neuherbergstr. 11, 80937, München, Deutschland,
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15
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Tian J, Tep C, Benedick A, Saidi N, Ryu JC, Kim ML, Sadasivan S, Oberdick J, Smeyne R, Zhu MX, Yoon SO. p75 regulates Purkinje cell firing by modulating SK channel activity through Rac1. J Biol Chem 2014; 289:31458-72. [PMID: 25253694 PMCID: PMC4223344 DOI: 10.1074/jbc.m114.589937] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/11/2014] [Indexed: 12/22/2022] Open
Abstract
p75 is expressed among Purkinje cells in the adult cerebellum, but its function has remained obscure. Here we report that p75 is involved in maintaining the frequency and regularity of spontaneous firing of Purkinje cells. The overall spontaneous firing activity of Purkinje cells was increased in p75(-/-) mice during the phasic firing period due to a longer firing period and accompanying reduction in silence period than in the wild type. We attribute these effects to a reduction in small conductance Ca(2+)-activated potassium (SK) channel activity in Purkinje cells from p75(-/-) mice compared with the wild type littermates. The mechanism by which p75 regulates SK channel activity appears to involve its ability to activate Rac1. In organotypic cultures of cerebellar slices, brain-derived neurotrophic factor increased RacGTP levels by activating p75 but not TrkB. These results correlate with a reduction in RacGTP levels in synaptosome fractions from the p75(-/-) cerebellum, but not in that from the cortex of the same animals, compared with wild type littermates. More importantly, we demonstrate that Rac1 modulates SK channel activity and firing patterns of Purkinje cells. Along with the finding that spine density was reduced in p75(-/-) cerebellum, these data suggest that p75 plays a role in maintaining normalcy of Purkinje cell firing in the cerebellum in part by activating Rac1 in synaptic compartments and modulating SK channels.
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Affiliation(s)
- JinBin Tian
- the Department of Neuroscience, Ohio State University, Columbus, Ohio 43210, the Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Chhavy Tep
- From the Department of Molecular and Cellular Biochemistry, the Biochemistry Program, and
| | - Alex Benedick
- From the Department of Molecular and Cellular Biochemistry
| | - Nabila Saidi
- From the Department of Molecular and Cellular Biochemistry
| | - Jae Cheon Ryu
- From the Department of Molecular and Cellular Biochemistry
| | - Mi Lyang Kim
- From the Department of Molecular and Cellular Biochemistry
| | - Shankar Sadasivan
- the Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, and
| | | | - Richard Smeyne
- the Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, and
| | - Michael X Zhu
- the Department of Neuroscience, Ohio State University, Columbus, Ohio 43210, the Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Sung Ok Yoon
- From the Department of Molecular and Cellular Biochemistry,
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16
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Gymnopoulos M, Cingolani LA, Pedarzani P, Stocker M. Developmental mapping of small-conductance calcium-activated potassium channel expression in the rat nervous system. J Comp Neurol 2014; 522:1072-101. [PMID: 24096910 PMCID: PMC4016743 DOI: 10.1002/cne.23466] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 09/06/2013] [Accepted: 09/17/2013] [Indexed: 12/22/2022]
Abstract
Early electrical activity and calcium influx regulate crucial aspects of neuronal development. Small-conductance calcium-activated potassium (SK) channels regulate action potential firing and shape calcium influx through feedback regulation in mature neurons. These functions, observed in the adult nervous system, make them ideal candidates to regulate activity-and calcium-dependent processes in neurodevelopment. However, to date little is known about the onset of expression and regions expressing SK channel subunits in the embryonic and postnatal development of the central nervous system (CNS). To allow studies on the contribution of SK channels to different phases of development of single neurons and networks, we have performed a detailed in situ hybridization mapping study, providing comprehensive distribution profiles of all three SK subunits (SK1, SK2, and SK3) in the rat CNS during embryonic and postnatal development. SK channel transcripts are expressed at early stages of prenatal CNS development. The three SK channel subunits display different developmental expression gradients in distinct CNS regions, with time points of expression and up-or downregulation that can be associated with a range of diverse developmental events. Their early expression in embryonic development suggests an involvement of SK channels in the regulation of developmental processes. Additionally, this study shows how the postnatal ontogenetic patterns lead to the adult expression map for each SK channel subunit and how their coexpression in the same regions or neurons varies throughout development. J. Comp. Neurol. 522:1072–1101, 2014. © 2013 Wiley Periodicals, Inc.
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Affiliation(s)
- Marco Gymnopoulos
- Department of Molecular Biology of Neuronal Signals, Max Planck Institute for Experimental Medicine, 37075, Göttingen, Germany
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17
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Steinestel K, Brüderlein S, Lennerz JK, Steinestel J, Kraft K, Pröpper C, Meineke V, Möller P. Expression and Y435-phosphorylation of Abelson interactor 1 (Abi1) promotes tumour cell adhesion, extracellular matrix degradation and invasion by colorectal carcinoma cells. Mol Cancer 2014; 13:145. [PMID: 24913355 PMCID: PMC4066275 DOI: 10.1186/1476-4598-13-145] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 06/02/2014] [Indexed: 12/14/2022] Open
Abstract
Background The Abelson tyrosine kinase (c-Abl) inhibitor STI571 (Glivec®) has been shown to effectively inhibit colorectal cancer cell migration and invasion. The c-Abl substrate abelson interactor 1 (Abi1) is a key regulator of actin reorganization and upregulated in colorectal carcinoma. The specific role of Abi1 in relation to extracellular matrix degradation and effects of targeting Abi1 phosphorylation have not yet been examined. Here, we investigated the role of Abi1 in relation to invasive properties in colorectal cancer. Methods and results In 56 primary human colorectal carcinoma samples, we found overexpression of Abi1 in 39% at the invasive edge of the tumour, associated with an infiltrative phenotype and high-grade tumour cell budding (p = 0.001). To explore the role of Abi1 in vitro, we employed the Abi1 expressing and KRAS-mutated CHD1 model and performed matrix degradation assays that showed Abi1 localization at specific sites of matrix degradation. Moreover, quantification of matrix dissolution demonstrated suppression after RNAi knockdown of Abi1 by 95% (p = 0.001). Importantly, treatment with STI571 did abolish Abi1 Y435-phosphorylation, suppressed the matrix dissolution, decreased fibronectin attachment, and suppressed cell invasion through reconstituted extracellular matrix. Conclusion Our data indicate that phosphorylated Abi1 contributes to the invasive properties of colorectal cancer.
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Affiliation(s)
- Konrad Steinestel
- Bundeswehr Institute of Radiobiology, Neuherbergstr, 11, 80937 Munich, Germany.
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18
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Jain N, Lim LW, Tan WT, George B, Makeyev E, Thanabalu T. Conditional N-WASP knockout in mouse brain implicates actin cytoskeleton regulation in hydrocephalus pathology. Exp Neurol 2014; 254:29-40. [DOI: 10.1016/j.expneurol.2014.01.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 01/08/2014] [Accepted: 01/14/2014] [Indexed: 01/09/2023]
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19
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Stockmann M, Linta L, Föhr KJ, Boeckers A, Ludolph AC, Kuh GF, Udvardi PT, Proepper C, Storch A, Kleger A, Liebau S, Boeckers TM. Developmental and functional nature of human iPSC derived motoneurons. Stem Cell Rev Rep 2014; 9:475-92. [PMID: 22048897 DOI: 10.1007/s12015-011-9329-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Marianne Stockmann
- Institute for Anatomy & Cell Biology, Ulm University, Albert-Einstein Allee 11, 89081 Ulm, Germany
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20
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Proepper C, Putz S, Russell R, Boeckers TM, Liebau S. The Kvβ2 subunit of voltage-gated potassium channels is interacting with ProSAP2/Shank3 in the PSD. Neuroscience 2013; 261:133-43. [PMID: 24211303 DOI: 10.1016/j.neuroscience.2013.10.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 10/21/2013] [Accepted: 10/22/2013] [Indexed: 01/18/2023]
Abstract
The postsynaptic density is an electron dense meshwork composed of a variety of molecules facilitating neuronal signal transmission. ProSAP2/Shank3 represents a crucial player at postsynaptic sites, assembling large multimeric platforms and anchoring numerous other molecules, thereby linking the functional synapse with the cytoskeleton. ProSAP2/Shank3 is also implicated in the pathogenesis of numerous diseases, including autism spectrum disorders. KvBeta2 (Kvβ2) on the other hand serves as a regulatory subunit of voltage-gated potassium channels. Kvβ2 is located at various sites in the neuron including the axon (binding to Kv1.2), the dendrites (binding to Kv4.2) and the synapse. Binding of Kvβ2 to either Kv1.2 or Kv4 modulates not only the channel conformation but directs targeting of the channel protein complex to distinct loci within the cell. Thus an interaction between ProSAP2 and Kvβ2 could have important roles at diverse cellular compartments and moreover during maturation stages. We report here on the direct protein-protein interaction of the postsynaptic density anchoring molecule ProSAP2 and the potassium channel subunit Kvβ2, initially identified in a yeast-two-hybrid-screen. Furthermore, we characterize this interaction at synapses using primary hippocampal neurons in vitro.
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Affiliation(s)
- C Proepper
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - S Putz
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - R Russell
- Department of Internal Medicine 1, Ulm University Hospital, Ulm, Germany
| | - T M Boeckers
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - S Liebau
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany; Institute of Neuroanatomy, University of Tuebingen, Tuebingen, Germany.
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21
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Heckman CA, Plummer HK. Filopodia as sensors. Cell Signal 2013; 25:2298-311. [PMID: 23876793 DOI: 10.1016/j.cellsig.2013.07.006] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 07/04/2013] [Accepted: 07/09/2013] [Indexed: 12/19/2022]
Abstract
Filopodia are sensors on both excitable and non-excitable cells. The sensing function is well documented in neurons and blood vessels of adult animals and is obvious during dorsal closure in embryonic development. Nerve cells extend neurites in a bidirectional fashion with growth cones at the tips where filopodia are concentrated. Their sensing of environmental cues underpins the axon's ability to "guide," bypassing non-target cells and moving toward the target to be innervated. This review focuses on the role of filopodia structure and dynamics in the detection of environmental cues, including both the extracellular matrix (ECM) and the surfaces of neighboring cells. Other protrusions including the stereocilia of the inner ear and epididymus, the invertebrate Type I mechanosensors, and the elongated processes connecting osteocytes, share certain principles of organization with the filopodia. Actin bundles, which may be inside or outside of the excitable cell, function to transduce stress from physical perturbations into ion signals. There are different ways of detecting such perturbations. Osteocyte processes contain an actin core and are physically anchored on an extracellular structure by integrins. Some Type I mechanosensors have bridge proteins that anchor microtubules to the membrane, but bundles of actin in accessory cells exert stress on this complex. Hair cells of the inner ear rely on attachments between the actin-based protrusions to activate ion channels, which then transduce signals to afferent neurons. In adherent filopodia, the focal contacts (FCs) integrated with ECM proteins through integrins may regulate integrin-coupled ion channels to achieve signal transduction. Issues that are not understood include the role of Ca(2+) influx in filopodia dynamics and how integrins coordinate or gate signals arising from perturbation of channels by environmental cues.
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Affiliation(s)
- C A Heckman
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403-0212, USA.
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22
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Steinestel J, Cronauer MV, Müller J, Al Ghazal A, Skowronek P, Arndt A, Kraft K, Schrader M, Schrader AJ, Steinestel K. Overexpression of p16(INK4a) in urothelial carcinoma in situ is a marker for MAPK-mediated epithelial-mesenchymal transition but is not related to human papillomavirus infection. PLoS One 2013; 8:e65189. [PMID: 23724131 PMCID: PMC3665800 DOI: 10.1371/journal.pone.0065189] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 04/22/2013] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The role of human papillomavirus (HPV) in bladder carcinogenesis remains controversial. Overexpression of p16(INK4a), a surrogate marker for infection with oncogenic HPV in other tumours, has been described for urothelial carcinoma in situ (UCIS). Our goal was therefore to evaluate whether overexpression of p16(INK4a) is associated with HPV infection and to identify mechanisms of p16(INK4a) upregulation in UCIS. MATERIALS AND METHODS In 60 tissue specimens from a total of 45 patients (UCIS and controls), we performed p16(INK4a) immunohistochemistry followed by detection and subclassification of HPV DNA. In a subset of samples, we tested for gene amplification of p16(INK4a) applying fluorescence in situ hybridization (FISH). RAS/MAPK signalling and epithelial-mesenchymal transition (EMT) was assessed using immunohistochemistry. Finally, we transfected urothelial carcinoma cells with KRAS and examined the expression of p16(INK4a) as well as markers of EMT. RESULTS We found overexpression of p16(INK4a) in 92.6% of UCIS and in all cervical intraepithelial neoplasia (CIN) controls. In contrast, we detected high-risk HPV DNA in 80% of CIN, but none in UCIS. There was no gene amplification of p16(INK4a). High levels of phosphorylated kinases and urokinase plasminogen activator (uPA) and loss of membraneous E-cadherin were detected in UCIS. KRAS transfection of urothelial carcinoma cells led to upregulation of p16(INK4a) and uPA accompanied by loss of E-cadherin that could be inhibited by application of the kinase-inhibitor Sorafenib. CONCLUSIONS Our results show that overexpression of p16(INK4a) in UCIS is neither associated with HPV infection nor p16(INK4a) gene amplification but is a consequence of enhanced RAS/MAPK signalling that promotes EMT, possibly due to Sorafenib-sensitive paracrine secretion of the EMT activator uPA. These findings might open a novel therapeutic option for localized but aggressive urothelial cancer.
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Affiliation(s)
| | | | | | | | - Peter Skowronek
- Gemeinschaftspraxis for Pathology Augsburg, Augsburg, Germany
| | - Annette Arndt
- Institute of Pathology and Molecular Pathology, Bundeswehrkrankenhaus Ulm, Ulm, Germany
| | - Klaus Kraft
- Institute of Pathology and Molecular Pathology, Bundeswehrkrankenhaus Ulm, Ulm, Germany
| | - Mark Schrader
- Department of Urology, University of Ulm, Ulm, Germany
| | | | - Konrad Steinestel
- Bundeswehr Institute of Radiobiology, Munich, Germany
- Institute of Pathology, University of Ulm, Ulm, Germany
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23
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Linta L, Stockmann M, Lin Q, Lechel A, Proepper C, Boeckers TM, Kleger A, Liebau S. Microarray-Based Comparisons of Ion Channel Expression Patterns: Human Keratinocytes to Reprogrammed hiPSCs to Differentiated Neuronal and Cardiac Progeny. Stem Cells Int 2013; 2013:784629. [PMID: 23690787 PMCID: PMC3649712 DOI: 10.1155/2013/784629] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 03/06/2013] [Indexed: 11/17/2022] Open
Abstract
Ion channels are involved in a large variety of cellular processes including stem cell differentiation. Numerous families of ion channels are present in the organism which can be distinguished by means of, for example, ion selectivity, gating mechanism, composition, or cell biological function. To characterize the distinct expression of this group of ion channels we have compared the mRNA expression levels of ion channel genes between human keratinocyte-derived induced pluripotent stem cells (hiPSCs) and their somatic cell source, keratinocytes from plucked human hair. This comparison revealed that 26% of the analyzed probes showed an upregulation of ion channels in hiPSCs while just 6% were downregulated. Additionally, iPSCs express a much higher number of ion channels compared to keratinocytes. Further, to narrow down specificity of ion channel expression in iPS cells we compared their expression patterns with differentiated progeny, namely, neurons and cardiomyocytes derived from iPS cells. To conclude, hiPSCs exhibit a very considerable and diverse ion channel expression pattern. Their detailed analysis could give an insight into their contribution to many cellular processes and even disease mechanisms.
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Affiliation(s)
- Leonhard Linta
- Institute for Anatomy Cell Biology, Ulm University, Albert-Einstein Allee 11, 89081 Ulm, Germany
| | - Marianne Stockmann
- Institute for Anatomy Cell Biology, Ulm University, Albert-Einstein Allee 11, 89081 Ulm, Germany
| | - Qiong Lin
- Institute for Biomedical Engineering, Department of Cell Biology, RWTH Aachen, Pauwelstrasse 30, 52074 Aachen, Germany
| | - André Lechel
- Department of Internal Medicine I, Ulm University, Albert-Einstein Allee 11, 89081 Ulm, Germany
| | - Christian Proepper
- Institute for Anatomy Cell Biology, Ulm University, Albert-Einstein Allee 11, 89081 Ulm, Germany
| | - Tobias M. Boeckers
- Institute for Anatomy Cell Biology, Ulm University, Albert-Einstein Allee 11, 89081 Ulm, Germany
| | - Alexander Kleger
- Department of Internal Medicine I, Ulm University, Albert-Einstein Allee 11, 89081 Ulm, Germany
| | - Stefan Liebau
- Institute for Anatomy Cell Biology, Ulm University, Albert-Einstein Allee 11, 89081 Ulm, Germany
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Linta L, Boeckers TM, Kleger A, Liebau S. Calcium activated potassium channel expression during human iPS cell-derived neurogenesis. Ann Anat 2013; 195:303-311. [PMID: 23587809 DOI: 10.1016/j.aanat.2013.02.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 02/05/2013] [Accepted: 02/27/2013] [Indexed: 01/11/2023]
Abstract
The family of calcium activated potassium channels of low and intermediate conductance, known as SK channels, consists of four members (SK1-4). These channels are widely expressed throughout the organism and involved in various cellular processes, such as the afterhyperpolarization in excitable cells but also in differentiation processes of various tissues. To date, the role of SK channels in developmental processes has been merely a marginal focus of investigation, although it is well accepted that cell differentiation and maturation affect the expression patterns of certain ion channels. Recently, several studies from our laboratory delineated the influence of SK channel expression and their respective activity on cytoskeletal reorganization in neural and pluripotent stem cells and regulation of cell fate determination toward the cardiac lineage in human and mouse pluripotent stem cells. Herein, we have now analyzed SK channel expression patterns and distribution at various stages of human induced pluripotent stem cell-derived neurogenesis particularly focusing on undifferentiated iPS cells, neural progenitors and mature neurons. All family members could be detected starting at the iPS cell level and were differentially expressed during the subsequent maturation process. Intriguingly, we found obvious discrepancies between mRNA and protein expression pointing toward a complex regulatory mechanism. Inhibition of SK channels with either apamin or clotrimazol did not have any significant effects on the speed or amount of neurogenesis in vitro. The abundance and specific regulation of SK channel expression during iPS cell differentiation indicates distinct roles of these ion channels not only for the cardiac but also for neuronal cell differentiation and in vitro neurogenesis.
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Affiliation(s)
- Leonhard Linta
- Institute for Anatomy & Cell Biology, Ulm University, Ulm, Germany
| | | | - Alexander Kleger
- Department of Internal Medicine I, Ulm University, Ulm, Germany.
| | - Stefan Liebau
- Institute for Anatomy & Cell Biology, Ulm University, Ulm, Germany.
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25
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Burianek LE, Soderling SH. Under lock and key: spatiotemporal regulation of WASP family proteins coordinates separate dynamic cellular processes. Semin Cell Dev Biol 2013; 24:258-66. [PMID: 23291261 DOI: 10.1016/j.semcdb.2012.12.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 11/21/2012] [Accepted: 12/14/2012] [Indexed: 02/03/2023]
Abstract
WASP family proteins are nucleation promoting factors that bind to and activate the Arp2/3 complex in order to stimulate nucleation of branched actin filaments. The WASP family consists of WASP, N-WASP, WAVE1-3, WASH, and the novel family members WHAMM and JMY. Each of the family members contains a C-terminus responsible for their nucleation promoting activity and unique N-termini that allow for them to be regulated in a spatiotemporal manner. Upon activation they reorganize the cytoskeleton for different cellular functions depending on their subcellular localization and regulatory protein interactions. Emerging evidence indicates that WASH, WHAMM, and JMY have functions that require the coordination of both actin polymerization and microtubule dynamics. Here, we review the mechanisms of regulation for each family member and their associated in vivo functions including cell migration, vesicle trafficking, and neuronal development.
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Ca2+ activated K channels-new tools to induce cardiac commitment from pluripotent stem cells in mice and men. Stem Cell Rev Rep 2012; 8:720-40. [PMID: 22038332 DOI: 10.1007/s12015-011-9324-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Activity-dependent modulation of the interaction between CaMKIIα and Abi1 and its involvement in spine maturation. J Neurosci 2012; 32:13177-88. [PMID: 22993434 DOI: 10.1523/jneurosci.2257-12.2012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Remodeling of dendritic spines through regulation of actin dynamics is a key event in activity-dependent structural plasticity. However, the molecular mechanism underlying this process is poorly understood. Here, we show that activity-dependent modulation of Abl interactor 1-Ca(2+)/calmodulin-dependent kinase IIα (Abi1-CaMKIIα) interaction, and thereby their activity, is important for regulation of spine morphology in cultured rat hippocampal neurons. Abi1 interacts with CaMKIIα at resting conditions through Abi1's tSNARE (target membrane-associated SNARE), which harbors striking homology with CaMKIIα regulatory domain. The interaction of the two proteins, Abi1 and CaMKIIα, results in their simultaneous inhibition, inhibition of CaMKIIα activity, and also inhibition of Abi1-dependent Rac activation. Their functional impediment is released when they dissociate from each other by calmodulin binding through glutamate receptor activation. Before dissociation, Abi1 is phosphorylated by CaMKIIα at serine 88, which may involve in regulation of Rac activation and spine maturation. Our results suggest that modulation of the interaction between Abi1 and CaMKIIα, through the glutamate receptor pathway, may be a molecular mechanism underlying activity-regulated structural plasticity in rat hippocamapal neurons.
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The dynactin p150 subunit: cell biology studies of sequence changes found in ALS/MND and Parkinsonian Syndromes. J Neural Transm (Vienna) 2012; 120:785-98. [DOI: 10.1007/s00702-012-0910-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 10/20/2012] [Indexed: 01/11/2023]
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Park SS, Kim MO, Yun SP, Ryu JM, Park JH, Seo BN, Jeon JH, Han HJ. C(16)-Ceramide-induced F-actin regulation stimulates mouse embryonic stem cell migration: involvement of N-WASP/Cdc42/Arp2/3 complex and cofilin-1/α-actinin. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:350-60. [PMID: 22989773 DOI: 10.1016/j.bbalip.2012.09.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 08/31/2012] [Accepted: 09/08/2012] [Indexed: 01/15/2023]
Abstract
Ceramide, a major structural element in the cellular membrane, is a key regulatory factor in various cellular behaviors that are dependent on ceramide-induced association of specific proteins. However, molecular mechanisms that regulate ceramide-induced embryonic stem cell (ESC) migration are still not well understood. Thus, we investigated the effect of ceramide on migration and its related signal pathways in mouse ESCs. Among ceramide species with different fatty acid chain lengths, C(16)-Cer increased migration of mouse ESCs in a dose- (≥1μM) and time-dependent (≥8h) manners, as determined by the cell migration assay. C(16)-Cer (10μM) increased protein-kinase C (PKC) phosphorylation. Subsequently, C(16)-Cer increased focal adhesion kinase (FAK) and Paxillin phosphorylation, which were inhibited by PKC inhibitor Bisindolylmaleimide I (1μM). When we examined for the downstream signaling molecules, C(16)-Cer activated small G protein (Cdc42) and increased the formation of complex with Neural Wiskott-Aldrich Syndrome Protein (N-WASP)/Cdc42/Actin-Related Protein 2/3 (Arp2/3). This complex formation was disrupted by FAK- and Paxillin-specific siRNAs. Furthermore, C(16)-Cer-induced increase of filamentous actin (F-actin) expression was inhibited by Cdc42-, N-WASP-, and Arp2/3-specific siRNAs, respectively. Indeed, C(16)-Cer increased cofilin-1/F-actin interaction or F-actin/α-actinin-1 and α-actinin-4 interactions in the cytoskeleton compartment, which was reversed by Cdc42-specific siRNA. Finally, C(16)-Cer-induced increase of cell migration was inhibited by knocking down each signal pathway-related molecules with siRNA or inhibitors. In conclusion, C(16)-Cer enhances mouse ESC migration through the regulation of PKC and FAK/Paxillin-dependent N-WASP/Cdc42/Arp2/3 complex formation as well as through promoting the interaction between cofilin-1 or α-actinin-1/-4 and F-actin.
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Affiliation(s)
- Su Shin Park
- Department of Veterinary Physiology, Biotherapy Human Resources Center (BK 21), College of Veterinary Medicine, Chonnam National University, Gwangju 500-757, Republic of Korea
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Steinestel K, Brüderlein S, Steinestel J, Märkl B, Schwerer MJ, Arndt A, Kraft K, Pröpper C, Möller P. Expression of Abelson interactor 1 (Abi1) correlates with inflammation, KRAS mutation and adenomatous change during colonic carcinogenesis. PLoS One 2012; 7:e40671. [PMID: 22808230 PMCID: PMC3393686 DOI: 10.1371/journal.pone.0040671] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Accepted: 06/11/2012] [Indexed: 01/29/2023] Open
Abstract
Background Abelson interactor 1 (Abi1) is an important regulator of actin dynamics during cytoskeletal reorganization. In this study, our aim was to investigate the expression of Abi1 in colonic mucosa with and without inflammation, colonic polyps, colorectal carcinomas (CRC) and metastases as well as in CRC cell lines with respect to BRAF/KRAS mutation status and to find out whether introduction of KRAS mutation or stimulation with TNFalpha enhances Abi1 protein expression in CRC cells. Methodology/Principal Findings We immunohistochemically analyzed Abi1 protein expression in 126 tissue specimens from 95 patients and in 5 colorectal carcinoma cell lines with different mutation status by western immunoblotting. We found that Abi1 expression correlated positively with KRAS, but not BRAF mutation status in the examined tissue samples. Furthermore, Abi1 is overexpressed in inflammatory mucosa, sessile serrated polyps and adenomas, tubular adenomas, invasive CRC and CRC metastasis when compared to healthy mucosa and BRAF-mutated as well as KRAS wild-type hyperplastic polyps. Abi1 expression in carcinoma was independent of microsatellite stability of the tumor. Abi1 protein expression correlated with KRAS mutation in the analyzed CRC cell lines, and upregulation of Abi1 could be induced by TNFalpha treatment as well as transfection of wild-type CRC cells with mutant KRAS. The overexpression of Abi1 could be abolished by treatment with the PI3K-inhibitor Wortmannin after KRAS transfection. Conclusions/Significance Our results support a role for Abi1 as a downstream target of inflammatory response and adenomatous change as well as oncogenic KRAS mutation via PI3K, but not BRAF activation. Furthermore, they highlight a possible role for Abi1 as a marker for early KRAS mutation in hyperplastic polyps. Since the protein is a key player in actin dynamics, our data encourages further studies concerning the exact role of Abi1 in actin reorganization upon enhanced KRAS/PI3K signalling during colonic tumorigenesis.
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Tubulin-binding cofactor B is a direct interaction partner of the dynactin subunit p150(Glued). Cell Tissue Res 2012; 350:13-26. [PMID: 22777741 DOI: 10.1007/s00441-012-1463-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 05/31/2012] [Indexed: 10/28/2022]
Abstract
The dynactin p150(Glued) subunit, encoded by the gene DCTN1, is part of the dynein-dynactin motor protein complex responsible for retrograde axonal transport in motor neurons. The p150 subunit is a candidate gene for neurodegenerative diseases, in particular motor neuron and extrapyramidal diseases. Tubulin-binding cofactors are believed to be involved in tubulin biogenesis and degradation and therefore to contribute to microtubule functional diversity and regulation. A yeast-two-hybrid screen for putative interacting proteins of dynactin p150(Glued) has revealed tubulin-folding cofactor B (TBCB). We analyzed the interaction of these proteins and investigated the impact of this complex on the microtubule network in cell lines and primary hippocampal neurons in vitro. We especially concentrated on neuronal morphology and synaptogenesis. Overexpression of both proteins or depletion of TBCB alone does not alter the microtubule network and/or neuronal morphology. The demonstration of the interaction of the transport molecule dynactin and the tubulin-regulating factor TBCB is thought to have an impact on several cellular mechanisms. TBCB expression levels have been found to have only a subtle influence on the microtubule network and neuronal morphology. However, overexpression of TBCB leads to the decreased localization of p150 to the microtubule network that might result in a functional modulation of this protein complex.
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Heinrich J, Proepper C, Schmidt T, Linta L, Liebau S, Boeckers TM. The postsynaptic density protein Abelson interactor protein 1 interacts with the motor protein Kinesin family member 26B in hippocampal neurons. Neuroscience 2012; 221:86-95. [PMID: 22766233 DOI: 10.1016/j.neuroscience.2012.06.055] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 06/22/2012] [Accepted: 06/23/2012] [Indexed: 11/24/2022]
Abstract
Abelson interactor protein 1 (Abi-1) localizes to postsynaptic densities (PSDs) of excitatory synapses and was shown to be transported from the PSD to the nucleus and back depending upon synaptic activation. We employed a yeast-two-hybrid screen to search for putative transport molecules. We found Kif26B a member of the Kif family of transport proteins that has not been characterized in the central nervous system as a direct interaction partner of Abi-1. We delineated a proline-rich motif within the cargo-binding domain of Kif26B to be responsible for this protein-protein interaction. Kif26B was able to recruit Abi-1 to the microtubule network and we found that the expression of Kif26B is responsible for the localization of Abi-1 to PSDs in maturing neurons. Taken together we report that Abi-1 is a cargo of Kif26B in primary hippocampal neurons, pointing to a role of this transport molecule in the movement of Abi-1 between different cell compartments. Additionally, we provide the first detailed investigation of Kif26B and its cargo molecules in neuronal cells.
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Affiliation(s)
- J Heinrich
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
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Ladiwala U, Basu H, Mathur D. Assembling neurospheres: dynamics of neural progenitor/stem cell aggregation probed using an optical trap. PLoS One 2012; 7:e38613. [PMID: 22693648 PMCID: PMC3367915 DOI: 10.1371/journal.pone.0038613] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 05/07/2012] [Indexed: 11/18/2022] Open
Abstract
Optical trapping (tweezing) has been used in conjunction with fluid flow technology to dissect the mechanics and spatio-temporal dynamics of how neural progenitor/stem cells (NSCs) adhere and aggregate. Hitherto unavailable information has been obtained on the most probable minimum time (∼5 s) and most probable minimum distance of approach (4–6 µm) required for irreversible adhesion of proximate cells to occur. Our experiments also allow us to study and quantify the spatial characteristics of filopodial- and membrane-mediated adhesion, and to probe the functional dynamics of NSCs to quantify a lower limit of the adhesive force by which NSCs aggregate (∼18 pN). Our findings, which we also validate by computational modeling, have important implications for the neurosphere assay: once aggregated, neurospheres cannot disassemble merely by being subjected to shaking or by thermal effects. Our findings provide quantitative affirmation to the notion that the neurosphere assay may not be a valid measure of clonality and “stemness”. Post-adhesion dynamics were also studied and oscillatory motion in filopodia-mediated adhesion was observed. Furthermore, we have also explored the effect of the removal of calcium ions: both filopodia-mediated as well as membrane-membrane adhesion were inhibited. On the other hand, F-actin disrupted the dynamics of such adhesion events such that filopodia-mediated adhesion was inhibited but not membrane-membrane adhesion.
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Affiliation(s)
- Uma Ladiwala
- UM-DAE Centre for Excellence in Basic Science, University of Mumbai, Kalina Campus, Mumbai, India
- * E-mail: (UL); (DM)
| | - Himanish Basu
- Tata Institute of Fundamental Research, Mumbai, India
| | - Deepak Mathur
- Tata Institute of Fundamental Research, Mumbai, India
- * E-mail: (UL); (DM)
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Bae J, Sung BH, Cho IH, Kim SM, Song WK. NESH regulates dendritic spine morphology and synapse formation. PLoS One 2012; 7:e34677. [PMID: 22485184 PMCID: PMC3317636 DOI: 10.1371/journal.pone.0034677] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/06/2012] [Indexed: 11/18/2022] Open
Abstract
Background Dendritic spines are small membranous protrusions on the neuronal dendrites that receive synaptic input from axon terminals. Despite their importance for integrating the enormous information flow in the brain, the molecular mechanisms regulating spine morphogenesis are not well understood. NESH/Abi-3 is a member of the Abl interactor (Abi) protein family, and its overexpression is known to reduce cell motility and tumor metastasis. NESH is prominently expressed in the brain, but its function there remains unknown. Methodology/Principal Findings NESH was strongly expressed in the hippocampus and moderately expressed in the cerebral cortex, cerebellum and striatum, where it co-localized with the postsynaptic proteins PSD95, SPIN90 and F-actin in dendritic spines. Overexpression of NESH reduced numbers of mushroom-type spines and synapse density but increased thin, filopodia-like spines and had no effect on spine density. siRNA knockdown of NESH also reduced mushroom spine numbers and inhibited synapse formation but it increased spine density. The N-terminal region of NESH co-sedimented with filamentous actin (F-actin), which is an essential component of dendritic spines, suggesting this interaction is important for the maturation of dendritic spines. Conclusions/Significance NESH is a novel F-actin binding protein that likely plays important roles in the regulation of dendritic spine morphogenesis and synapse formation.
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Affiliation(s)
- Jeomil Bae
- Cell Dynamics and Bioimaging Research Center, School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Bong Hwan Sung
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - In Ha Cho
- Cell Dynamics and Bioimaging Research Center, School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Seon-Myung Kim
- Department of Cell Biology and Neurology, Center for Neurodegenerative Diseases, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Woo Keun Song
- Cell Dynamics and Bioimaging Research Center, School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
- * E-mail:
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Kania G, Boheler KR, Landmesser U, Wojakowski W. Stem cells in heart failure. Stem Cells Int 2011; 2011:193918. [PMID: 22190962 PMCID: PMC3236426 DOI: 10.4061/2011/193918] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 10/17/2011] [Indexed: 11/20/2022] Open
Affiliation(s)
- Gabriela Kania
- Cardioimmunology, Cardiovascular Research, Institute of Physiology, University of Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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Proepper C, Steinestel K, Schmeisser MJ, Heinrich J, Steinestel J, Bockmann J, Liebau S, Boeckers TM. Heterogeneous nuclear ribonucleoprotein k interacts with Abi-1 at postsynaptic sites and modulates dendritic spine morphology. PLoS One 2011; 6:e27045. [PMID: 22102872 PMCID: PMC3216941 DOI: 10.1371/journal.pone.0027045] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 10/09/2011] [Indexed: 12/31/2022] Open
Abstract
Background Abelson-interacting protein 1 (Abi-1) plays an important role for dendritic branching and synapse formation in the central nervous system. It is localized at the postsynaptic density (PSD) and rapidly translocates to the nucleus upon synaptic stimulation. At PSDs Abi-1 is in a complex with several other proteins including WASP/WAVE or cortactin thereby regulating the actin cytoskeleton via the Arp 2/3 complex. Principal Findings We identified heterogeneous nuclear ribonucleoprotein K (hnRNPK), a 65 kDa ssDNA/RNA-binding-protein that is involved in multiple intracellular signaling cascades, as a binding partner of Abi-1 at postsynaptic sites. The interaction with the Abi-1 SH3 domain is mediated by the hnRNPK-interaction (KI) domain. We further show that during brain development, hnRNPK expression becomes more and more restricted to granule cells of the cerebellum and hippocampal neurons where it localizes in the cell nucleus as well as in the spine/dendritic compartment. The downregulation of hnRNPK in cultured hippocampal neurons by RNAi results in an enlarged dendritic tree and a significant increase in filopodia formation. This is accompanied by a decrease in the number of mature synapses. Both effects therefore mimic the neuronal morphology after downregulation of Abi-1 mRNA in neurons. Conclusions Our findings demonstrate a novel interplay between hnRNPK and Abi-1 in the nucleus and at synaptic sites and show obvious similarities regarding both protein knockdown phenotypes. This indicates that hnRNPK and Abi-1 act synergistic in a multiprotein complex that regulates the crucial balance between filopodia formation and synaptic maturation in neurons.
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Affiliation(s)
| | - Konrad Steinestel
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
- Department of Pathology, BWK Hospital Ulm, Ulm, Germany
| | | | - Jutta Heinrich
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Julie Steinestel
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Juergen Bockmann
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Stefan Liebau
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
- * E-mail: (TMB); (SL)
| | - Tobias M. Boeckers
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
- * E-mail: (TMB); (SL)
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Liebau S, Tischendorf M, Ansorge D, Linta L, Stockmann M, Weidgang C, Iacovino M, Boeckers T, von Wichert G, Kyba M, Kleger A. An inducible expression system of the calcium-activated potassium channel 4 to study the differential impact on embryonic stem cells. Stem Cells Int 2011; 2011:456815. [PMID: 21941566 PMCID: PMC3173888 DOI: 10.4061/2011/456815] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 06/14/2011] [Indexed: 11/20/2022] Open
Abstract
Rationale. The family of calcium-activated potassium channels consists of four members with varying biological functions and conductances. Besides membrane potential modulation, SK channels have been found to be involved in cardiac pacemaker cell development from ES cells and morphological shaping of neural stem cells. Objective. Distinct SK channel subtype expression in ES cells might elucidate their precise impact during cardiac development. We chose SK channel subtype 4 as a potential candidate influencing embryonic stem cell differentiation. Methods. We generated a doxycycline inducible mouse ES cell line via targeted homologous recombination of a cassette expressing a bicistronic construct encoding SK4 and a fluorophore from the murine HPRT locus. Conclusion. We characterized the mouse ES cell line iSK4-AcGFP. The cassette is readily expressed under the control of doxycycline, and the overexpression of SK4 led to an increase in cardiac and pacemaker cell differentiation thereby serving as a unique tool to characterize the cell biological variances due to specific SK channel overexpression.
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Affiliation(s)
- Stefan Liebau
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
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Stephan R, Gohl C, Fleige A, Klämbt C, Bogdan S. Membrane-targeted WAVE mediates photoreceptor axon targeting in the absence of the WAVE complex in Drosophila. Mol Biol Cell 2011; 22:4079-92. [PMID: 21900504 PMCID: PMC3204070 DOI: 10.1091/mbc.e11-02-0121] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A tight spatial-temporal coordination of F-actin dynamics is crucial for a large variety of cellular processes that shape cells. The Abelson interactor (Abi) has a conserved role in Arp2/3-dependent actin polymerization, regulating Wiskott-Aldrich syndrome protein (WASP) and WASP family verprolin-homologous protein (WAVE). In this paper, we report that Abi exerts nonautonomous control of photoreceptor axon targeting in the Drosophila visual system through WAVE. In abi mutants, WAVE is unstable but restored by reexpression of Abi, confirming that Abi controls the integrity of the WAVE complex in vivo. Remarkably, expression of a membrane-tethered WAVE protein rescues the axonal projection defects of abi mutants in the absence of the other subunits of the WAVE complex, whereas cytoplasmic WAVE only slightly affects the abi mutant phenotype. Thus complex formation not only stabilizes WAVE, but also provides further membrane-recruiting signals, resulting in an activation of WAVE.
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Affiliation(s)
- Raiko Stephan
- Institut für Neurobiologie, Universität Münster, 48149 Münster, Germany
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Linta L, Stockmann M, Kleinhans KN, Böckers A, Storch A, Zaehres H, Lin Q, Barbi G, Böckers TM, Kleger A, Liebau S. Rat embryonic fibroblasts improve reprogramming of human keratinocytes into induced pluripotent stem cells. Stem Cells Dev 2011; 21:965-76. [PMID: 21699413 DOI: 10.1089/scd.2011.0026] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Patient-specific human induced pluripotent stem (hiPS) cells not only provide a promising tool for cellular disease models in general, but also open up the opportunity to establish cell-type-specific systems for personalized medicine. One of the crucial prerequisites for these strategies, however, is a fast and efficient reprogramming strategy from easy accessible somatic cell populations. Keratinocytes from plucked human hair had been introduced as a superior cell source for reprogramming purposes compared with the widely used skin fibroblasts. The starting cell population is, however, limited and thereby further optimization in terms of time, efficiency, and quality is inevitable. Here we show that rat embryonic fibroblasts (REFs) should replace mouse embryonic fibroblasts as feeder cells in the reprogramming process. REFs enable a significantly more efficient reprogramming procedure as shown by colony number and total amount of SSEA4-positive cells. We successfully produced keratinocyte-derived hiPS (k-hiPS) cells from various donors. The arising k-hiPS cells display the hallmarks of pluripotency such as expression of stem cell markers and differentiation into all 3 germ layers. The increased reprogramming efficiency using REFs as a feeder layer occurred independent of the proliferation rate in the parental keratinocytes and acts, at least in part, in a non-cell autonomous way by secreting factors known to facilitate pluripotency such as Tgfb1, Inhba and Grem1. Hence, we provide an easy to use and highly efficient reprogramming system that could be very useful for a broad application to generate human iPS cells.
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Affiliation(s)
- Leonhard Linta
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
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Calcium-Activated Potassium Channels, Cardiogenesis of Pluripotent Stem Cells, and Enrichment of Pacemaker-Like Cells. Trends Cardiovasc Med 2011; 21:74-83. [DOI: 10.1016/j.tcm.2012.03.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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