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Wilson ER, Nunes GDF, Shen S, Moore S, Gawron J, Maxwell J, Syed U, Hurley E, Lanka M, Qu J, Désaubry L, Wrabetz L, Poitelon Y, Feltri ML. Loss of prohibitin 2 in Schwann cells dysregulates key transcription factors controlling developmental myelination. Glia 2024. [PMID: 39215540 DOI: 10.1002/glia.24610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 07/18/2024] [Accepted: 08/13/2024] [Indexed: 09/04/2024]
Abstract
Schwann cells are critical for the proper development and function of the peripheral nervous system (PNS), where they form a collaborative relationship with axons. Past studies highlighted that a pair of proteins called the prohibitins play major roles in Schwann cell biology. Prohibitins are ubiquitously expressed and versatile proteins. We have previously shown that while prohibitins play a crucial role in Schwann cell mitochondria for long-term myelin maintenance and axon health, they may also be present at the Schwann cell-axon interface during development. Here, we expand on this, showing that drug-mediated modulation of prohibitins in vitro disrupts myelination and confirming that Schwann cell-specific ablation of prohibitin 2 (Phb2) in vivo results in severe defects in radial sorting and myelination. We show in vivo that Phb2-null Schwann cells cannot effectively proliferate and the transcription factors EGR2 (KROX20), POU3F1 (OCT6), and POU3F2 (BRN2), necessary for proper Schwann cell maturation, are dysregulated. Schwann cell-specific deletion of Jun, a transcription factor associated with negative regulation of myelination, confers partial rescue of the developmental defect seen in mice lacking Schwann cell Phb2. Finally, we identify a pool of candidate PHB2 interactors that change their interaction with PHB2 depending on neuronal signals, and thus are potential mediators of PHB2-associated developmental defects. This work develops our understanding of Schwann cell biology, revealing that Phb2 may modulate the timely expression of transcription factors necessary for proper PNS development, and proposing candidates that may play a role in PHB2-mediated integration of axon signals in the Schwann cell.
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Affiliation(s)
- Emma R Wilson
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, England, UK
| | - Gustavo Della-Flora Nunes
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Shichen Shen
- Department of Pharmaceutical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Seth Moore
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Joseph Gawron
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Jessica Maxwell
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Umair Syed
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Edward Hurley
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Meghana Lanka
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Jun Qu
- Department of Pharmaceutical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Laurent Désaubry
- Center of Research in Biomedicine of Strasbourg, Regenerative Nanomedicine (UMR 1260), INSERM, University of Strasbourg, Strasbourg, France
| | - Lawrence Wrabetz
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
- Department of Neurology, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Yannick Poitelon
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - M Laura Feltri
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
- Department of Neurology, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
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Wilson ER, Nunes GDF, Shen S, Moore S, Gawron J, Maxwell J, Syed U, Hurley E, Lanka M, Qu J, Desaubry L, Wrabetz L, Poitelon Y, Feltri ML. Loss of prohibitin 2 in Schwann cells dysregulates key transcription factors controlling developmental myelination. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.20.585915. [PMID: 38562812 PMCID: PMC10983910 DOI: 10.1101/2024.03.20.585915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Schwann cells are critical for the proper development and function of the peripheral nervous system, where they form a mutually beneficial relationship with axons. Past studies have highlighted that a pair of proteins called the prohibitins play major roles in Schwann cell biology. Prohibitins are ubiquitously expressed and versatile proteins. We have previously shown that while prohibitins play a crucial role in Schwann cell mitochondria for long-term myelin maintenance and axon health, they may also be present at the Schwann cell-axon interface during development. Here, we expand on this work, showing that drug-mediated modulation of prohibitins in vitro disrupts myelination and confirming that Schwann cell-specific ablation of prohibitin 2 (Phb2) in vivo results in early and severe defects in peripheral nerve development. Using a proteomic approach in vitro, we identify a pool of candidate PHB2 interactors that change their interaction with PHB2 depending on the presence of axonal signals. Furthermore, we show in vivo that loss of Phb2 in mouse Schwann cells causes ineffective proliferation and dysregulation of transcription factors EGR2 (KROX20), POU3F1 (OCT6) and POU3F2 (BRN2) that are necessary for proper Schwann cell maturation. Schwann cell-specific deletion of Jun, a transcription factor associated with negative regulation of myelination, confers partial rescue of the development defect seen in mice lacking Schwann cell Phb2. This work develops our understanding of Schwann cell biology, revealing that Phb2 may directly or indirectly modulate the timely expression of transcription factors necessary for proper peripheral nervous system development, and proposing candidates that may play a role in PHB2-mediated integration of axon signals in the Schwann cell.
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Affiliation(s)
- Emma R Wilson
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
- Department of Clinical Neurosciences, Cambridge University, Cambridge, UK
| | - Gustavo Della-Flora Nunes
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Shichen Shen
- Department of Pharmaceutical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Seth Moore
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Joseph Gawron
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Jessica Maxwell
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Umair Syed
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Edward Hurley
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Meghana Lanka
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Jun Qu
- Department of Pharmaceutical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Laurent Desaubry
- Center of Research in Biomedicine of Strasbourg, Regenerative Nanomedicine (UMR 1260), INSERM, University of Strasbourg, 67000 Strasbourg, France
| | - Lawrence Wrabetz
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
- Department of Neurology, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Yannick Poitelon
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - M Laura Feltri
- Department of Biochemistry, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
- Department of Neurology, Institute for Myelin and Glia Exploration, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
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Jiang J, Song B, Meng J, Zhou J. Tissue-specific RNA methylation prediction from gene expression data using sparse regression models. Comput Biol Med 2024; 169:107892. [PMID: 38171264 DOI: 10.1016/j.compbiomed.2023.107892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 12/19/2023] [Accepted: 12/20/2023] [Indexed: 01/05/2024]
Abstract
N6-methyladenosine (m6A) is a highly prevalent and conserved post-transcriptional modification observed in mRNA and long non-coding RNA (lncRNA). Identifying potential m6A sites within RNA sequences is crucial for unraveling the potential influence of the epitranscriptome on biological processes. In this study, we introduce Exp2RM, a novel approach that formulates single-site-based tissue-specific elastic net models for predicting tissue-specific methylation levels utilizing gene expression data. The resulting ensemble model demonstrates robust predictive performance for tissue-specific methylation levels, with an average R-squared value of 0.496 and a median R-squared value of 0.482 across all 22 human tissues. Since methylation distribution varies among tissues, we trained the model to incorporate similar patterns, significantly improves accuracy with the median R-squared value increasing to 0.728. Additonally, functional analysis reveals Exp2RM's ability to capture coefficient genes in relevant biological processes. This study emphasizes the importance of tissue-specific methylation distribution in enhancing prediction accuracy and provides insights into the functional implications of methylation sites.
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Affiliation(s)
- Jie Jiang
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, China; Institute of Systems, Molecular and Integrative Biology, University of Liverpool, L69 7ZB, Liverpool, United Kingdom
| | - Bowen Song
- Department of Public Health, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Jia Meng
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, China; AI University Research Centre, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, China; Institute of Systems, Molecular and Integrative Biology, University of Liverpool, L69 7ZB, Liverpool, United Kingdom
| | - Jingxian Zhou
- School of AI and Advanced Computing, Xi'an Jiaotong-Liverpool University Entrepreneur College (Taicang), Taicang, Suzhou, Jiangsu Province, 215400, China; Department of Computer Science, University of Liverpool, L69 7ZB, Liverpool, United Kingdom.
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Zhang S, Cai Z, Li H. AHNAKs roles in physiology and malignant tumors. Front Oncol 2023; 13:1258951. [PMID: 38033502 PMCID: PMC10682155 DOI: 10.3389/fonc.2023.1258951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 10/30/2023] [Indexed: 12/02/2023] Open
Abstract
The AHNAK family currently consists of two members, namely AHNAK and AHNAK2, both of which have a molecular weight exceeding 600 kDa. Homologous sequences account for approximately 90% of their composition, indicating a certain degree of similarity in terms of molecular structure and biological functions. AHNAK family members are involved in the regulation of various biological functions, such as calcium channel modulation and membrane repair. Furthermore, with advancements in biological and bioinformatics technologies, research on the relationship between the AHNAK family and tumors has rapidly increased in recent years, and its regulatory role in tumor progression has gradually been discovered. This article briefly describes the physiological functions of the AHNAK family, and reviews and analyzes the expression and molecular regulatory mechanisms of the AHNAK family in malignant tumors using Pubmed and TCGA databases. In summary, AHNAK participates in various physiological and pathological processes in the human body. In multiple types of cancers, abnormal expression of AHNAK and AHNAK2 is associated with prognosis, and they play a key regulatory role in tumor progression by activating signaling pathways such as ERK, MAPK, Wnt, and MEK, as well as promoting epithelial-mesenchymal transition.
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Affiliation(s)
- Shusen Zhang
- Hebei Province Xingtai People’s Hospital Postdoctoral Workstation, Xingtai, China
- Postdoctoral Mobile Station, Hebei Medical University, Shijiazhuang, China
- Department of Pulmonary and Critical Care Medicine, Affiliated Xing Tai People Hospital of Hebei Medical University, Xingtai, China
- The First Department of Pulmonary and Critical Care Medicine, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Zhigang Cai
- Postdoctoral Mobile Station, Hebei Medical University, Shijiazhuang, China
- The First Department of Pulmonary and Critical Care Medicine, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Hui Li
- Department of surgery, Affiliated Xing Tai People Hospital of Hebei Medical University, Xingtai, China
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5
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Feng Y, An R, Zhang Y, Chen M, Wang L, Duan Y, Xing C. AHNAK-modified microbubbles for the intracranial delivery of triptolide: in-vitro and in-vivo investigations. Int J Pharm 2022; 629:122351. [DOI: 10.1016/j.ijpharm.2022.122351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 10/01/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022]
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Regulatory significance of CULLIN2 in neuronal differentiation and regeneration. Neurochem Int 2022; 159:105386. [PMID: 35803325 DOI: 10.1016/j.neuint.2022.105386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 05/05/2022] [Accepted: 06/27/2022] [Indexed: 11/21/2022]
Abstract
BACKGROUND Scaffold proteins coordinate multiple signalling pathways by integrating various proteins but the role of these proteins in neuronal pathways remains to be elucidated. The present study focused to evaluate the expression of the scaffold protein CULLIN2 in neuronal cells. METHODS The neuronal precursor cell line N2A was differentiated to neurons in-vitro with retinoic acid and biochemical assays were used to understand the gene expression profiling of CULLIN2. Moreover, neddylation inhibitor MLN4924 was used to inhibit the activity of CULLIN2 and the downstream substrates were validated. Finally, the role of CULLIN2 in nerve regeneration was evaluated in an in vivo zebrafish model. RESULTS Experimental data showed that the neuronal cells N2A have lower expression of CULLIN2 compared to skin cell lines (HaCaT and A431) and inactivation with the neddylation inhibitor resulted in cell death. Furthermore differentiating the neural precursor cell line into neurons with retinoic acid enhanced the expression of CULLIN2. Examining downstream signalling molecules with the neddylation inhibitor illuminates that MLN4924 treatment influences the cytokine signalling cascade (JAK-STAT) in neuronal cells. Moreover, for the first time, we show that the ubiquitin ligase protein CULLIN2 is perturbed in neural regeneration. Expression profile of CULLIN2 was significantly decreased in response to a nerve injury in Zebra fish and as the nerve regenerates there is corresponding reduction in the mRNA levels. CONCLUSION During differentiation CULLIN2 is upregulated whereas during regeneration there is significant downregulation. Thus, our findings reveal a crucial role of the scaffold protein CULLIN2 in nerve differentiation and regeneration which can be vital for the treatment of nerve injury.
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Schwann cells contribute to keloid formation. Matrix Biol 2022; 108:55-76. [DOI: 10.1016/j.matbio.2022.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 01/27/2022] [Accepted: 03/04/2022] [Indexed: 02/07/2023]
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de Clauser L, Kappert C, Sondermann JR, Gomez-Varela D, Flatters SJL, Schmidt M. Proteome and Network Analysis Provides Novel Insights Into Developing and Established Chemotherapy-Induced Peripheral Neuropathy. Front Pharmacol 2022; 13:818690. [PMID: 35250568 PMCID: PMC8895144 DOI: 10.3389/fphar.2022.818690] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/12/2022] [Indexed: 01/09/2023] Open
Abstract
Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating side-effect of cancer therapies. So far, the development of CIPN cannot be prevented, neither can established CIPN be reverted, often leading to the cessation of necessary chemotherapy. Thus, there is an urgent need to explore the mechanistic basis of CIPN to facilitate its treatment. Here we used an integrated approach of quantitative proteome profiling and network analysis in a clinically relevant rat model of paclitaxel-induced peripheral neuropathy. We analysed lumbar rat DRG at two critical time points: (1) day 7, right after cessation of paclitaxel treatment, but prior to neuropathy development (pre-CIPN); (2) 4 weeks after paclitaxel initiation, when neuropathy has developed (peak-CIPN). In this way we identified a differential protein signature, which shows how changes in the proteome correlate with the development and maintenance of CIPN, respectively. Extensive biological pathway and network analysis reveals that, at pre-CIPN, regulated proteins are prominently implicated in mitochondrial (dys)function, immune signalling, neuronal damage/regeneration, and neuronal transcription. Orthogonal validation in an independent rat cohort confirmed the increase of β-catenin (CTNNB1) at pre-CIPN. More importantly, detailed analysis of protein networks associated with β-catenin highlights translationally relevant and potentially druggable targets. Overall, this study demonstrates the enormous value of combining animal behaviour with proteome and network analysis to provide unprecedented insights into the molecular basis of CIPN. In line with emerging approaches of network medicine our results highlight new avenues for developing improved therapeutic options aimed at preventing and treating CIPN.
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Affiliation(s)
- Larissa de Clauser
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
- *Correspondence: Larissa de Clauser, ; Manuela Schmidt,
| | - Christin Kappert
- Max Planck Institute of Experimental Medicine, Goettingen, Germany
| | - Julia R. Sondermann
- Division of Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - David Gomez-Varela
- Division of Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Sarah J. L. Flatters
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
| | - Manuela Schmidt
- Division of Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
- *Correspondence: Larissa de Clauser, ; Manuela Schmidt,
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Zardab M, Stasinos K, Grose RP, Kocher HM. The Obscure Potential of AHNAK2. Cancers (Basel) 2022; 14:cancers14030528. [PMID: 35158796 PMCID: PMC8833689 DOI: 10.3390/cancers14030528] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 12/17/2022] Open
Abstract
Simple Summary AHNAK2 is a relatively newly discovered protein. It can interact with many other proteins. This protein is increased in cells of variety of different cancers. AHNAK2 may play a vital role in cancer formation. AHNAK2 may have a role in early detection of cancer. This obscure potential of AHNAK2 is being studied. Abstract AHNAK2 is a protein discovered in 2004, with a strong association with oncogenesis in various epithelial cancers. It has a large 616 kDa tripartite structure and is thought to take part in the formation of large multi-protein complexes. High expression is found in clear cell renal carcinoma, pancreatic ductal adenocarcinoma, uveal melanoma, and lung adenocarcinoma, with a relation to poor prognosis. Little work has been done in exploring the function and relation AHNAK2 has with cancer, with early studies showing promising potential as a future biomarker and therapeutic target.
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Xiang X, Langlois S, St-Pierre ME, Blinder A, Charron P, Graber TE, Fowler SL, Baird SD, Bennett SAL, Alain T, Cowan KN. Identification of pannexin 1-regulated genes, interactome, and pathways in rhabdomyosarcoma and its tumor inhibitory interaction with AHNAK. Oncogene 2021; 40:1868-1883. [PMID: 33564071 PMCID: PMC7946643 DOI: 10.1038/s41388-020-01623-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 12/07/2020] [Accepted: 12/11/2020] [Indexed: 01/31/2023]
Abstract
Rhabdomyosarcoma (RMS), the most common soft tissue sarcoma in children, is an aggressive cancer with a poor prognosis. Despite current management, the 5-year survival rate for patients with metastatic RMS is ∼30%; underscoring the need to develop better treatment strategies. We have recently reported that pannexin 1 (PANX1) levels are downregulated in RMS and that restoring its expression inhibits RMS progression. Here, we have surveyed and characterized the molecular changes induced by PANX1 re-expression in RMS. We cataloged transcriptomic changes in this context by RNA sequencing. At the protein level, we unveiled PANX1 interactors using BioID, complemented by co-immunoprecipitation coupled to high-performance liquid chromatography/electrospray ionization tandem mass spectrometry performed in PANX1-enriched fractions. Using these data, we generated searchable public databases for the PANX1 interactome and changes to the RMS transcriptome occurring when PANX1 expression is restored. STRING network analyses revealed a PANX1 interactome involving plasma membrane and cytoskeleton-associated proteins including the previously undescribed interactor AHNAK. Indeed, AHNAK knockdown abrogated the PANX1-mediated reduction in RMS cell viability and migration. Using these unbiased approaches, we bring insight to the mechanisms by which PANX1 inhibits RMS progression, identifying the cell migration protein AHNAK as a key modifier of PANX1-mediated changes in RMS malignant properties.
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Affiliation(s)
- Xiao Xiang
- Molecular Biomedicine Program, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Stéphanie Langlois
- Molecular Biomedicine Program, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Department of Surgery, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, ON, Canada
| | - Marie-Eve St-Pierre
- Molecular Biomedicine Program, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Anna Blinder
- Molecular Biomedicine Program, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Philippe Charron
- Molecular Biomedicine Program, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Tyson E Graber
- Molecular Biomedicine Program, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Stephanie L Fowler
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
- Neural Regeneration Laboratory and Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON, Canada
- UK Dementia Research Institute, University College London, London, UK
| | - Stephen D Baird
- Molecular Biomedicine Program, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Steffany A L Bennett
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
- Neural Regeneration Laboratory and Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON, Canada
| | - Tommy Alain
- Molecular Biomedicine Program, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Kyle N Cowan
- Molecular Biomedicine Program, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada.
- Department of Surgery, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, ON, Canada.
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Kaupang Å, Hansen TV. The PPAR Ω Pocket: Renewed Opportunities for Drug Development. PPAR Res 2020; 2020:9657380. [PMID: 32695150 PMCID: PMC7351019 DOI: 10.1155/2020/9657380] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 05/13/2020] [Indexed: 12/13/2022] Open
Abstract
The past decade of PPARγ research has dramatically improved our understanding of the structural and mechanistic bases for the diverging physiological effects of different classes of PPARγ ligands. The discoveries that lie at the heart of these developments have enabled the design of a new class of PPARγ ligands, capable of isolating central therapeutic effects of PPARγ modulation, while displaying markedly lower toxicities than previous generations of PPARγ ligands. This review examines the emerging framework around the design of these ligands and seeks to unite its principles with the development of new classes of ligands for PPARα and PPARβ/δ. The focus is on the relationships between the binding modes of ligands, their influence on PPAR posttranslational modifications, and gene expression patterns. Specifically, we encourage the design and study of ligands that primarily bind to the Ω pockets of PPARα and PPARβ/δ. In support of this development, we highlight already reported ligands that if studied in the context of this new framework may further our understanding of the gene programs regulated by PPARα and PPARβ/δ. Moreover, recently developed pharmacological tools that can be utilized in the search for ligands with new binding modes are also presented.
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Affiliation(s)
- Åsmund Kaupang
- Section for Pharmaceutical Chemistry, Department of Pharmacy, University of Oslo, 0316 Oslo, Norway
| | - Trond Vidar Hansen
- Section for Pharmaceutical Chemistry, Department of Pharmacy, University of Oslo, 0316 Oslo, Norway
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12
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Kaupang Å, Laitinen T, Poso A, Hansen TV. Structural review of PPARγ in complex with ligands: Cartesian- and dihedral angle principal component analyses of X-ray crystallographic data. Proteins 2017; 85:1684-1698. [PMID: 28543443 DOI: 10.1002/prot.25325] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 05/03/2017] [Accepted: 05/17/2017] [Indexed: 12/22/2022]
Abstract
Two decades of research into the ligand-dependent modulation of the activity of the peroxisome proliferator-activated receptor γ (PPARγ) have demonstrated the heterogeneous modes of action of PPARγ ligands, in terms of their interaction surfaces in the ligand-binding pocket, binding stoichiometry and ability to interact with functionally important parts of the receptor, through both direct and allosteric mechanisms. These findings signal the complex mechanistic bases of the distinct biological effects of different classes of PPARγ ligands. Today, the development of PPARγ ligands focuses on partial- and non-agonists as opposed to classical agonists, due to the severe side effects observed with PPARγ classical agonists as therapeutic agents. To aid this development, we performed principal component analyses of the atomic (Cartesian) coordinates (cPCA) and dihedral angles (dPCA) of the structures of human PPARγ from X-ray crystallography, available in the public domain, seeking to reveal ligand-induced trends. In the cPCA, projections of the structures along the principal components (PCs) demonstrated a moderate correlation between cPC1 and structural parameters related to the stabilization of helix 12, which is central to the transcriptional activation by PPARγ classical agonists. Consequently, the presented cPCA mapping of the PPARγ-ligand complexes may guide in silico drug discovery programs seeking to avoid stabilization of helix 12 in their development of partial- and non-agonistic PPARγ ligands. Notably, while the dPCA could identify key regions of dihedral fluctuation in the structural ensemble, the distributions along dPC1 - 2 could not be classified according to the same parameters as the distribution along cPC1. Proteins 2017; 85:1684-1698. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Åsmund Kaupang
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, P.O. Box 1068, Blindern, Oslo, 0316, Norway
| | - Tuomo Laitinen
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Eastern Finland, P.O. Box 1627, Kuopio, Finland
| | - Antti Poso
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Eastern Finland, P.O. Box 1627, Kuopio, Finland
| | - Trond Vidar Hansen
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, P.O. Box 1068, Blindern, Oslo, 0316, Norway
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Maddala R, Walters M, Brophy PJ, Bennett V, Rao PV. Ankyrin-B directs membrane tethering of periaxin and is required for maintenance of lens fiber cell hexagonal shape and mechanics. Am J Physiol Cell Physiol 2015; 310:C115-26. [PMID: 26538089 DOI: 10.1152/ajpcell.00111.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 10/31/2015] [Indexed: 12/22/2022]
Abstract
Periaxin (Prx), a PDZ domain protein expressed preferentially in myelinating Schwann cells and lens fibers, plays a key role in membrane scaffolding and cytoarchitecture. Little is known, however, about how Prx is anchored to the plasma membrane. Here we report that ankyrin-B (AnkB), a well-characterized adaptor protein involved in linking the spectrin-actin cytoskeleton to integral membrane proteins, is required for membrane association of Prx in lens fibers and colocalizes with Prx in hexagonal fiber cells. Under AnkB haploinsufficiency, Prx accumulates in the soluble fraction with a concomitant loss from the membrane-enriched fraction of mouse lenses. Moreover, AnkB haploinsufficiency induced age-dependent disruptions in fiber cell hexagonal geometry and radial alignment and decreased compressive stiffness in mouse lenses parallel to the changes observed in Prx null mouse lens. Both AnkB- and Prx-deficient mice exhibit disruptions in membrane organization of the spectrin-actin network and the dystrophin-glycoprotein complex in lens fiber cells. Taken together, these observations reveal that AnkB is required for Prx membrane anchoring and for maintenance of lens fiber cell hexagonal geometry, membrane skeleton organization, and biomechanics.
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Affiliation(s)
- Rupalatha Maddala
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina
| | - Mark Walters
- Department of Mechanical Engineering and Materials Science, Pratt School of Engineering, Duke University, Durham, North Carolina
| | - Peter J Brophy
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom
| | - Vann Bennett
- Howard Hughes Medical Institute, Chevy Chase, Maryland; Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina; and
| | - Ponugoti V Rao
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina; Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina
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14
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Shin JH, Kim YN, Kim IY, Choi DH, Yi SS, Seong JK. Increased Cell Proliferations and Neurogenesis in the Hippocampal Dentate Gyrus of Ahnak Deficient Mice. Neurochem Res 2015; 40:1457-62. [DOI: 10.1007/s11064-015-1615-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 05/06/2015] [Accepted: 05/12/2015] [Indexed: 10/23/2022]
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15
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Davis TA, Loos B, Engelbrecht AM. AHNAK: the giant jack of all trades. Cell Signal 2014; 26:2683-93. [PMID: 25172424 DOI: 10.1016/j.cellsig.2014.08.017] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 08/08/2014] [Accepted: 08/18/2014] [Indexed: 12/19/2022]
Abstract
The nucleoprotein AHNAK is an unusual and somewhat mysterious scaffolding protein characterised by its large size of approximately 700 kDa. Several aspects of this protein remain uncertain, including its exact molecular function and regulation on both the gene and protein levels. Various studies have attempted to annotate AHNAK and, notably, protein interaction and expression analyses have contributed greatly to our current understanding of the protein. The implicated biological processes are, however, very diverse, ranging from a role in the formation of the blood-brain barrier, cell architecture and migration, to the regulation of cardiac calcium channels and muscle membrane repair. In addition, recent evidence suggests that AHNAK might be yet another accomplice in the development of tumour metastasis. This review will discuss the different functional roles of AHNAK, highlighting recent advancements that have added foundation to the proposed roles while identifying ties between them. Implications for related fields of research are noted and suggestions for future research that will assist in unravelling the function of AHNAK are offered.
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Affiliation(s)
- T A Davis
- Department of Physiological Sciences, University of Stellenbosch, Mike de Vries Building, c/o Merriman Avenue and Bosman Street, Stellenbosch 7600, South Africa.
| | - B Loos
- Department of Physiological Sciences, University of Stellenbosch, Mike de Vries Building, c/o Merriman Avenue and Bosman Street, Stellenbosch 7600, South Africa
| | - A-M Engelbrecht
- Department of Physiological Sciences, University of Stellenbosch, Mike de Vries Building, c/o Merriman Avenue and Bosman Street, Stellenbosch 7600, South Africa
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16
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von Boxberg Y, Soares S, Féréol S, Fodil R, Bartolami S, Taxi J, Tricaud N, Nothias F. Giant scaffolding protein AHNAK1 interacts with β-dystroglycan and controls motility and mechanical properties of Schwann cells. Glia 2014; 62:1392-406. [PMID: 24796807 DOI: 10.1002/glia.22685] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 04/11/2014] [Accepted: 04/17/2014] [Indexed: 01/02/2023]
Abstract
The profound morphofunctional changes that Schwann cells (SCs) undergo during their migration and elongation on axons, as well as during axon sorting, ensheathment, and myelination, require their close interaction with the surrounding laminin-rich basal lamina. In contrast to myelinating central nervous system glia, SCs strongly and constitutively express the giant scaffolding protein AHNAK1, localized essentially underneath the outer, abaxonal plasma membrane. Using electron microscopy, we show here that in the sciatic nerve of ahnak1(-) (/) (-) mice the ultrastructure of myelinated, and unmyelinated (Remak) fibers is affected. The major SC laminin receptor β-dystroglycan co-immunoprecipitates with AHNAK1 shows reduced expression in ahnak1(-) (/) (-) SCs, and is no longer detectable in Cajal bands on myelinated fibers in ahnak1(-) (/) (-) sciatic nerve. Reduced migration velocity in a scratch wound assay of purified ahnak1(-) (/) (-) primary SCs cultured on a laminin substrate indicated a function of AHNAK1 in SC motility. This was corroborated by atomic force microscopy measurements, which revealed a greater mechanical rigidity of shaft and leading tip of ahnak1(-) (/) (-) SC processes. Internodal lengths of large fibers are decreased in ahnak1(-) (/) (-) sciatic nerve, and longitudinal extension of myelin segments is even more strongly reduced after acute knockdown of AHNAK1 in SCs of developing sciatic nerve. Together, our results suggest that by interfering in the cross-talk between the transmembrane form of the laminin receptor dystroglycan and F-actin, AHNAK1 influences the cytoskeleton organization of SCs, and thus plays a role in the regulation of their morphology and motility and lastly, the myelination process.
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Affiliation(s)
- Ysander von Boxberg
- Sorbonne Universités, UPMC CR18 (NPS), Paris, France; Neuroscience Paris Seine (NPS), CNRS UMR 8246, Paris, France; Neuroscience Paris Seine (NPS), INSERM U1130, Paris, France
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17
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Milbreta U, von Boxberg Y, Mailly P, Nothias F, Soares S. Astrocytic and vascular remodeling in the injured adult rat spinal cord after chondroitinase ABC treatment. J Neurotrauma 2014; 31:803-18. [PMID: 24380419 DOI: 10.1089/neu.2013.3143] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Upregulation of extracellular chondroitin sulfate proteoglycans (CSPG) is a primary cause for the failure of axons to regenerate after spinal cord injury (SCI), and the beneficial effect of their degradation by chondroitinase ABC (ChABC) is widely documented. Little is known, however, about the effect of ChABC treatment on astrogliosis and revascularization, two important factors influencing axon regrowth. This was investigated in the present study. Immediately after a spinal cord hemisection at thoracic level 8-9, we injected ChABC intrathecally at the sacral level, repeated three times until 10 days post-injury. Our results show an effective cleavage of CSPG glycosaminoglycan chains and stimulation of axonal remodeling within the injury site, accompanied by an extended period of astrocyte remodeling (up to 4 weeks). Interestingly, ChABC treatment favored an orientation of astrocytic processes directed toward the injury, in close association with axons at the lesion entry zone, suggesting a correlation between axon and astrocyte remodeling. Further, during the first weeks post-injury, ChABC treatment affected the morphology of laminin-positive blood vessel basement membranes and vessel-independent laminin deposits: hypertrophied blood vessels with detached or duplicated basement membrane were more numerous than in lesioned untreated animals. In contrast, at later time points, laminin expression increased and became more directly associated with newly formed blood vessels, the size of which tended to be closer to that found in intact tissue. Our data reinforce the idea that ChABC injection in combination with other synergistic treatments is a promising therapeutic strategy for SCI repair.
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Affiliation(s)
- Ulla Milbreta
- 1 Neuroscience Paris Seine/UMR8246/U1130/UMCR18 , IBPS/UPMC Univ Paris 06, Paris, France
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18
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Brain site-specific proteome changes in aging-related dementia. Exp Mol Med 2013; 45:e39. [PMID: 24008896 PMCID: PMC3789264 DOI: 10.1038/emm.2013.76] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Revised: 06/09/2013] [Accepted: 06/18/2013] [Indexed: 12/12/2022] Open
Abstract
This study is aimed at gaining insights into the brain site-specific proteomic senescence signature while comparing physiologically aged brains with aging-related dementia brains (for example, Alzheimer's disease (AD)). Our study of proteomic differences within the hippocampus (Hp), parietal cortex (pCx) and cerebellum (Cb) could provide conceptual insights into the molecular mechanisms involved in aging-related neurodegeneration. Using an isobaric tag for relative and absolute quantitation (iTRAQ)-based two-dimensional liquid chromatography coupled with tandem mass spectrometry (2D-LC-MS/MS) brain site-specific proteomic strategy, we identified 950 proteins in the Hp, pCx and Cb of AD brains. Of these proteins, 31 were significantly altered. Most of the differentially regulated proteins are involved in molecular transport, nervous system development, synaptic plasticity and apoptosis. Particularly, proteins such as Gelsolin (GSN), Tenascin-R (TNR) and AHNAK could potentially act as novel biomarkers of aging-related neurodegeneration. Importantly, our Ingenuity Pathway Analysis (IPA)-based network analysis further revealed ubiquitin C (UBC) as a pivotal protein to interact with diverse AD-associated pathophysiological molecular factors and suggests the reduced ubiquitin proteasome degradation system (UPS) as one of the causative factors of AD.
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19
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Vergé V, Lozano JC, Schatt P, Peaucellier G. SGEBP, a giant protein from starfish oocytes able to interact with ERK. Mol Reprod Dev 2013; 80:816-25. [PMID: 23794267 DOI: 10.1002/mrd.22210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 06/14/2013] [Indexed: 11/12/2022]
Abstract
The mitogen-activated protein kinase (MAPK) pathway is a key regulator of animal meiotic divisions. It involves cascades of kinases whose specificity has been shown to depend on binding proteins acting as scaffolds. We searched for proteins interacting with starfish extracellular signal-regulated kinase (ERK) using the yeast two-hybrid system. An interacting clone was found to encode the 5' region of a giant 16.7-kb transcript encoded by an intronless gene. The corresponding 630-kDa protein could not be detected by Western blot, but the meiotic spindle was labelled by immunolocalization with an antibody against the ERK-binding domain. A related gene was found in the genome of another starfish species, and similarities were also found to a 42.9-kb open reading frame in the sea urchin genome. Yet, no conserved protein-binding domain was detected in the amino acid sequence(s) compared to all the known motifs. Structure prediction software indicated that the encoded proteins are probably disordered while a query of the disordered protein database indicated some similarity with vertebrates microtubule-associated protein 2 (MAP2). This predicts that SGEBP may function as a space-filling polymer, having a role in both cytoskeleton organization and ERK targeting.
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Affiliation(s)
- Valérie Vergé
- UPMC Univ Paris 06, Laboratoire Arago, Avenue Fontaulé, BP44F-66650, Banyuls/mer, France
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20
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de Morrée A, Flix B, Bagaric I, Wang J, van den Boogaard M, Grand Moursel L, Frants RR, Illa I, Gallardo E, Toes R, van der Maarel SM. Dysferlin regulates cell adhesion in human monocytes. J Biol Chem 2013; 288:14147-14157. [PMID: 23558685 DOI: 10.1074/jbc.m112.448589] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dysferlin is mutated in a group of muscular dystrophies commonly referred to as dysferlinopathies. It is highly expressed in skeletal muscle, where it is important for sarcolemmal maintenance. Recent studies show that dysferlin is also expressed in monocytes. Moreover, muscle of dysferlinopathy patients is characterized by massive immune cell infiltrates, and dysferlin-negative monocytes were shown to be more aggressive and phagocytose more particles. This suggests that dysferlin deregulation in monocytes might contribute to disease progression, but the molecular mechanism is unclear. Here we show that dysferlin expression is increased with differentiation in human monocytes and the THP1 monocyte cell model. Freshly isolated monocytes of dysferlinopathy patients show deregulated expression of fibronectin and fibronectin-binding integrins, which is recapitulated by transient knockdown of dysferlin in THP1 cells. Dysferlin forms a protein complex with these integrins at the cell membrane, and its depletion impairs cell adhesion. Moreover, patient macrophages show altered adhesion and motility. These findings suggest that dysferlin is involved in regulating cellular interactions and provide new insight into dysferlin function in inflammatory cells.
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Affiliation(s)
- Antoine de Morrée
- Department of Human Genetics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Bàrbara Flix
- Servei de Neurologia, Laboratori de Neurologia Experimental, Hospital de la Santa Creu i Sant Pau i Institut de Recerca de HSCSP, Universitat Autònoma de Barcelona and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), 08193 Bellaterra, Spain
| | - Ivana Bagaric
- Department of Human Genetics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Jun Wang
- Department of Rheumatology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | | | - Laure Grand Moursel
- Department of Human Genetics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Rune R Frants
- Department of Human Genetics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Isabel Illa
- Servei de Neurologia, Laboratori de Neurologia Experimental, Hospital de la Santa Creu i Sant Pau i Institut de Recerca de HSCSP, Universitat Autònoma de Barcelona and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), 08193 Bellaterra, Spain
| | - Eduard Gallardo
- Servei de Neurologia, Laboratori de Neurologia Experimental, Hospital de la Santa Creu i Sant Pau i Institut de Recerca de HSCSP, Universitat Autònoma de Barcelona and Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), 08193 Bellaterra, Spain
| | - Rene Toes
- Department of Rheumatology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Silvère M van der Maarel
- Department of Human Genetics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands.
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21
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Kim HL, Seo YR. Identification of potential molecular biomarkers in response to thioredoxin reductase 1 deficiency under nickel exposure. BIOCHIP JOURNAL 2012. [DOI: 10.1007/s13206-012-6208-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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22
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The RNA-binding protein human antigen R controls global changes in gene expression during Schwann cell development. J Neurosci 2012; 32:4944-58. [PMID: 22492050 DOI: 10.1523/jneurosci.5868-11.2012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
An important prerequisite to myelination in peripheral nerves is the establishment of one-to-one relationships between axons and Schwann cells. This patterning event depends on immature Schwann cell proliferation, apoptosis, and morphogenesis, which are governed by coordinated changes in gene expression. Here, we found that the RNA-binding protein human antigen R (HuR) was highly expressed in immature Schwann cells, where genome-wide identification of its target mRNAs in vivo in mouse sciatic nerves using ribonomics showed an enrichment of functionally related genes regulating these processes. HuR coordinately regulated expression of several genes to promote proliferation, apoptosis, and morphogenesis in rat Schwann cells, in response to NRG1, TGFβ, and laminins, three major signals implicated in this patterning event. Strikingly, HuR also binds to several mRNAs encoding myelination-related proteins but, contrary to its typical function, negatively regulated their expression, likely to prevent ectopic myelination during development. These functions of HuR correlated with its abundance and subcellular localization, which were regulated by different signals in Schwann cells.
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Ahnak1 abnormally localizes in muscular dystrophies and contributes to muscle vesicle release. J Muscle Res Cell Motil 2011; 32:271-80. [PMID: 22057634 PMCID: PMC3230764 DOI: 10.1007/s10974-011-9271-8] [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: 08/24/2011] [Accepted: 10/19/2011] [Indexed: 11/27/2022]
Abstract
Ahnak1 is a giant, ubiquitously expressed, plasma membrane support protein whose function in skeletal muscle is largely unknown. Therefore, we investigated whether ahnak would be influenced by alterations of the sarcolemma exemplified by dysferlin mutations known to render the sarcolemma vulnerable or by mutations in calpain3, a protease known to cleave ahnak. Human muscle biopsy specimens obtained from patients with limb girdle muscular dystrophy (LGMD) caused by mutations in dysferlin (LGMD2B) and calpain3 (LGMD2A) were investigated for ahnak expression and localization. We found that ahnak1 has lost its sarcolemmal localization in LGMD2B but not in LGMD2A. Instead ahnak1 appeared in muscle connective tissue surrounding the extracellular site of the muscle fiber in both muscular dystrophies. The entire giant ahnak1 molecule was present outside the muscle fiber and did only partially colocalize with CD45-positive immune cell infiltration and the extracelluar matrix proteins fibronectin and collagenVI. Further, vesicles shedded in response to Ca2+ by primary human myotubes were purified and their protein content was analysed. Ahnak1 was prominently present in these vesicles. Electron microscopy revealed a homogenous population of vesicles with a diameter of about 150 nm. This is the first study demonstrating vesicle release from human myotubes that may be one mechanism underlying abnormally localized ahnak1. Taken together, our results define ahnak1 in muscle connective tissue as a novel feature of two genetically distinct muscular dystrophies that might contribute to disease pathology.
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24
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de Morrée A, Droog M, Grand Moursel L, Bisschop IJM, Impagliazzo A, Frants RR, Klooster R, van der Maarel SM. Self-regulated alternative splicing at the AHNAK locus. FASEB J 2011; 26:93-103. [PMID: 21940993 DOI: 10.1096/fj.11-187971] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AHNAK is a 700-kDa protein involved in cytoarchitecture and calcium signaling. It is secondarily reduced in muscle of dysferlinopathy patients and accumulates in muscle of calpainopathy patients, both affected by a muscular dystrophy. AHNAK directly interacts with dysferlin. This interaction is lost on cleavage of AHNAK by the protease calpain 3, explaining the molecular observations in patients. Currently, little is known of AHNAK regulation. We describe the self-regulation of multiple mRNA transcripts emanating from the AHNAK locus in muscle cells. We show that the AHNAK gene consists of a 17-kb exon flanked by multiple small exons. This genetic structure is shared by AHNAK2 and Periaxin, which share a common ancestor. Two major AHNAK transcripts are differentially expressed during muscle differentiation that encode for a small (17-kDa) and a large (700-kDa) protein isoform. These proteins interact in the cytoplasm, but the small AHNAK is also present in the nucleus. During muscle differentiation the small AHNAK is strongly increased, thereby establishing a positive feedback loop to regulate mRNA splicing of its own locus. A small 17-kDa isoform of Periaxin similarly traffics between the cytoplasm and the nucleus to regulate mRNA splicing. Thus, AHNAK constitutes a novel mechanism in post-transcriptional control of gene expression.
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Affiliation(s)
- Antoine de Morrée
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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25
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Maddala R, Skiba NP, Lalane R, Sherman DL, Brophy PJ, Rao PV. Periaxin is required for hexagonal geometry and membrane organization of mature lens fibers. Dev Biol 2011; 357:179-90. [PMID: 21745462 PMCID: PMC3164832 DOI: 10.1016/j.ydbio.2011.06.036] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 06/14/2011] [Accepted: 06/14/2011] [Indexed: 01/06/2023]
Abstract
Transparency of the ocular lens depends on symmetric packing and membrane organization of highly elongated hexagonal fiber cells. These cells possess an extensive, well-ordered cortical cytoskeleton to maintain cell shape and to anchor membrane components. Periaxin (Prx), a PDZ domain protein involved in myelin sheath stabilization, is also a component of adhaerens plaques in lens fiber cells. Here we show that Prx is expressed in lens fibers and exhibits maturation dependent redistribution, clustering discretely at the tricellular junctions in mature fiber cells. Prx exists in a macromolecular complex with proteins involved in membrane organization including ankyrin-B, spectrin, NrCAM, filensin, ezrin and desmoyokin. Importantly, Prx knockout mouse lenses were found to be softer and more easily deformed than normal lenses, revealing disruptions in fiber cell hexagonal packing, membrane skeleton and membrane stability. These observations suggest a key role for Prx in maturation, packing, and membrane organization of lens fiber cells. Hence, there may be functional parallels between the roles of Prx in membrane stabilization of the myelin sheath and the lens fiber cell.
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Affiliation(s)
- Rupalatha Maddala
- Department of Ophthalmology, Duke University School of Medicine, NC. USA
| | - Nikolai P. Skiba
- Department of Ophthalmology, Duke University School of Medicine, NC. USA
| | - Robert Lalane
- Department of Ophthalmology, Duke University School of Medicine, NC. USA
| | - Diane L. Sherman
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, UK
| | - Peter J. Brophy
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, UK
| | - Ponugoti V. Rao
- Department of Ophthalmology, Duke University School of Medicine, NC. USA
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, NC. USA
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26
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Choi JH, Banks AS, Estall JL, Kajimura S, Boström P, Laznik D, Ruas JL, Chalmers MJ, Kamenecka TM, Blüher M, Griffin PR, Spiegelman BM. Anti-diabetic drugs inhibit obesity-linked phosphorylation of PPARgamma by Cdk5. Nature 2010; 466:451-6. [PMID: 20651683 PMCID: PMC2987584 DOI: 10.1038/nature09291] [Citation(s) in RCA: 693] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Accepted: 06/24/2010] [Indexed: 12/22/2022]
Abstract
Obesity induced in mice by high-fat feeding activates the protein kinase cdk5 in adipose tissues. This results in phosphorylation of the nuclear receptor PPARγ, a dominant regulator of adipogenesis and fat cell gene expression, at serine 273. This modification of PPARγ does not alter its adipogenic capacity, but leads to dysregulation of a large number of genes whose expression is altered in obesity, including a reduction in the expression of the insulin-sensitizing adipokine, adiponectin. The phosphorylation of PPARγ by cdk5 is blocked by anti-diabetic PPARγ ligands, such as rosiglitazone and MRL24. This inhibition works both in vivo and in vitro, and surprisingly, is completely independent of classical receptor transcriptional agonism. Similarly, inhibition of PPARγ phosphorylation in obese patients by rosiglitazone is very tightly associated with the anti-diabetic effects of this drug. These data strongly suggest that cdk5-mediated phosphorylation of PPARγ may be involved in the pathogenesis of insulin-resistance, and present an opportunity for development of an improved generation of anti-diabetic drugs through PPARγ.
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Affiliation(s)
- Jang Hyun Choi
- Department of Cancer Biology and Division of Metabolism and Chronic Disease, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA
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27
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Alvarez JL, Petzhold D, Pankonien I, Behlke J, Kouno M, Vassort G, Morano I, Haase H. Ahnak1 modulates L-type Ca2+ channel inactivation of rodent cardiomyocytes. Pflugers Arch 2010; 460:719-30. [DOI: 10.1007/s00424-010-0853-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 05/28/2010] [Accepted: 06/02/2010] [Indexed: 01/21/2023]
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Biological role of dystroglycan in Schwann cell function and its implications in peripheral nervous system diseases. J Biomed Biotechnol 2010; 2010:740403. [PMID: 20625412 PMCID: PMC2896880 DOI: 10.1155/2010/740403] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Accepted: 04/20/2010] [Indexed: 11/17/2022] Open
Abstract
Dystroglycan is a central component of the dystrophin-glycoprotein complex (DGC) that links extracellular matrix with cytoskeleton, expressed in a variety of fetal and adult tissues. Dystroglycan plays diverse roles in development and homeostasis including basement membrane formation, epithelial morphogenesis, membrane stability, cell polarization, and cell migration. In this paper, we will focus on biological role of dystroglycan in Schwann cell function, especially myelination. First, we review the molecular architecture of DGC in Schwann cell abaxonal membrane. Then, we will review the loss-of-function studies using targeted mutagenesis, which have revealed biological functions of each component of DGC in Schwann cells. Based on these findings, roles of dystroglycan in Schwann cell function, in myelination in particular, and its implications in diseases will be discussed in detail. Finally, in view of the fact that understanding the role of dystroglycan in Schwann cells is just beginning, future perspectives will be discussed.
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