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González-Reyes M, Aragón J, Sánchez-Trujillo A, Rodríguez-Martínez G, Duarte K, Eleftheriou E, Barnier JV, Naquin D, Thermes C, Romo-Yáñez J, Roger JE, Rendon A, Vaillend C, Montanez C. Expression of Dystrophin Dp71 Splice Variants Is Temporally Regulated During Rodent Brain Development. Mol Neurobiol 2024:10.1007/s12035-024-04232-2. [PMID: 38802640 DOI: 10.1007/s12035-024-04232-2] [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: 12/12/2023] [Accepted: 05/13/2024] [Indexed: 05/29/2024]
Abstract
Dystrophin Dp71 is the major product of the Duchenne muscular dystrophy (DMD) gene in the brain, and its loss in DMD patients and mouse models leads to cognitive impairments. Dp71 is expressed as a range of proteins generated by alternative splicing of exons 71 to 74 and 78, classified in the main Dp71d and Dp71f groups that contain specific C-terminal ends. However, it is unknown whether each isoform has a specific role in distinct cell types, brain regions, and/or stages of brain development. In the present study, we characterized the expression of Dp71 isoforms during fetal (E10.5, E15.5) and postnatal (P1, P7, P14, P21 and P60) mouse and rat brain development. We finely quantified the expression of several Dp71 transcripts by RT-PCR and cloning assays in samples from whole-brain and distinct brain structures. The following Dp71 transcripts were detected: Dp71d, Dp71d∆71, Dp71d∆74, Dp71d∆71,74, Dp71d∆71-74, Dp71f, Dp71f∆71, Dp71f∆74, Dp71f∆71,74, and Dp71fΔ71-74. We found that the Dp71f isoform is the main transcript expressed at E10.5 (> 80%), while its expression is then progressively reduced and replaced by the expression of isoforms of the Dp71d group from E15.5 to postnatal and adult ages. This major finding was confirmed by third-generation nanopore sequencing. In addition, we found that the level of expression of specific Dp71 isoforms varies as a function of postnatal stages and brain structure. Our results suggest that Dp71 isoforms have different and complementary roles during embryonic and postnatal brain development, likely taking part in a variety of maturation processes in distinct cell types.
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Affiliation(s)
- Mayram González-Reyes
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Mexico City, Mexico
- Institut des Neurosciences Paris Saclay, Université Paris-Saclay, CNRS, Saclay, 91400, France
| | - Jorge Aragón
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Mexico City, Mexico
- Institut de la Vision, Sorbonne Université-INSERM-CNRS, 17 rue Moreau, Paris, 75012, France
| | - Alejandra Sánchez-Trujillo
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Mexico City, Mexico
| | - Griselda Rodríguez-Martínez
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Mexico City, Mexico
- Laboratorio de Investigación en Inmunología y Proteómica, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Kevin Duarte
- Institut des Neurosciences Paris Saclay, Université Paris-Saclay, CNRS, Saclay, 91400, France
| | - Evangelia Eleftheriou
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, 91198, France
| | - Jean-Vianney Barnier
- Institut des Neurosciences Paris Saclay, Université Paris-Saclay, CNRS, Saclay, 91400, France
| | - Delphine Naquin
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, 91198, France
| | - Claude Thermes
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, 91198, France
| | - José Romo-Yáñez
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Mexico City, Mexico
- Institut de la Vision, Sorbonne Université-INSERM-CNRS, 17 rue Moreau, Paris, 75012, France
- Coordinación de Endocrinología Ginecológica y Perinatal, Instituto Nacional de Perinatología, Mexico City, Mexico
| | - Jérome E Roger
- Institut des Neurosciences Paris Saclay, Université Paris-Saclay, CNRS, Saclay, 91400, France
- CERTO-Retina France, Saclay, 91400, France
| | - Alvaro Rendon
- Institut de la Vision, Sorbonne Université-INSERM-CNRS, 17 rue Moreau, Paris, 75012, France
| | - Cyrille Vaillend
- Institut des Neurosciences Paris Saclay, Université Paris-Saclay, CNRS, Saclay, 91400, France.
| | - Cecilia Montanez
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Mexico City, Mexico.
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Rein-Fischboeck L, Pohl R, Haberl EM, Mages W, Girke P, Liebisch G, Krautbauer S, Buechler C. Lower adiposity does not protect beta-2 syntrophin null mice from hepatic steatosis and inflammation in experimental non-alcoholic steatohepatitis. Gene 2023; 859:147209. [PMID: 36681100 DOI: 10.1016/j.gene.2023.147209] [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: 06/17/2022] [Revised: 12/21/2022] [Accepted: 01/13/2023] [Indexed: 01/19/2023]
Abstract
Visceral adiposity is strongly associated with liver steatosis, which predisposes to the development of non-alcoholic steatohepatitis (NASH). Mice with loss of the molecular adapter protein beta-2 syntrophin (SNTB2) have greatly reduced intra-abdominal fat mass. Hepatic expression of proteins with a role in fatty acid metabolism such as fatty acid synthase was nevertheless normal. This was also the case for proteins regulating cholesterol synthesis and uptake. Yet, a slight induction of hepatic cholesterol was noticed in the mutant mice. When mice were fed a methionine choline deficient (MCD) diet to induce NASH, liver cholesteryl ester content was induced in the wild type but not the mutant mice. Serum cholesterol of the mice fed a MCD diet declined and this was significant for the SNTB2 null mice. Though the mutant mice lost less fat mass than the wild type animals, hepatic triglyceride levels were similar between the groups. Proteins involved in fatty acid or cholesterol metabolism such as fatty acid synthase, apolipoprotein E and low-density lipoprotein receptor did not differ between the genotypes. Hepatic oxidative stress and liver inflammation of mutant and wild type mice were comparable. Mutant mice had lower hepatic levels of secondary bile acids and higher cholesterol storage in epididymal fat, and this may partly prevent hepatic cholesterol deposition. In summary, the current study shows that SNTB2 null mice have low intra-abdominal fat mass and do not accumulate hepatic cholesteryl esters when fed a MCD diet. Nevertheless, the SNTB2 null mice develop a similar NASH pathology as wild type mice suggesting a minor role of intra-abdominal fat and liver cholesteryl esters in this model.
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Affiliation(s)
- Lisa Rein-Fischboeck
- Department of Internal Medicine I, Regensburg University Hospital, D-93053 Regensburg, Germany
| | - Rebekka Pohl
- Department of Internal Medicine I, Regensburg University Hospital, D-93053 Regensburg, Germany
| | - Elisabeth M Haberl
- Department of Internal Medicine I, Regensburg University Hospital, D-93053 Regensburg, Germany
| | - Wolfgang Mages
- Department of Genetics, University of Regensburg, D-93040 Regensburg, Germany
| | - Philipp Girke
- Department of Genetics, University of Regensburg, D-93040 Regensburg, Germany
| | - Gerhard Liebisch
- Institute of Clinical Chemistry and Laboratory Medicine, Regensburg University Hospital, D-93053 Regensburg, Germany
| | - Sabrina Krautbauer
- Institute of Clinical Chemistry and Laboratory Medicine, Regensburg University Hospital, D-93053 Regensburg, Germany
| | - Christa Buechler
- Department of Internal Medicine I, Regensburg University Hospital, D-93053 Regensburg, Germany.
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3
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Bahouth SW, Nooh MM, Mancarella S. Involvement of SAP97 anchored multiprotein complexes in regulating cardiorenal signaling and trafficking networks. Biochem Pharmacol 2023; 208:115406. [PMID: 36596415 DOI: 10.1016/j.bcp.2022.115406] [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: 10/26/2022] [Revised: 12/26/2022] [Accepted: 12/28/2022] [Indexed: 01/02/2023]
Abstract
SAP97 is a member of the MAGUK family of proteins, but unlike other MAGUK proteins that are selectively expressed in the CNS, SAP97 is also expressed in peripheral organs, like the heart and kidneys. SAP97 has several protein binding cassettes, and this review will describe their involvement in creating SAP97-anchored multiprotein networks. SAP97-anchored networks localized at the inner leaflet of the cell membrane play a major role in trafficking and targeting of membrane G protein-coupled receptors (GPCR), channels, and structural proteins. SAP97 plays a major role in compartmentalizing voltage gated sodium and potassium channels to specific cellular compartments of heart cells. SAP97 undergoes extensive alternative splicing. These splice variants give rise to different SAP97 isoforms that alter its cellular localization, networking, signaling and trafficking effects. Regarding GPCR, SAP97 binds to the β1-adrenergic receptor and recruits AKAP5/PKA and PDE4D8 to create a multiprotein complex that regulates trafficking and signaling of cardiac β1-AR. In the kidneys, SAP97 anchored networks played a role in trafficking of aquaporin-2 water channels. Cardiac specific ablation of SAP97 (SAP97-cKO) resulted in cardiac hypertrophy and failure in aging mice. Similarly, instituting transverse aortic constriction (TAC) in young SAP97 c-KO mice exacerbated TAC-induced cardiac remodeling and dysfunction. These findings highlight a critical role for SAP97 in the pathophysiology of a number of cardiac and renal diseases, suggesting that SAP97 is a relevant target for drug discovery.
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Affiliation(s)
- Suleiman W Bahouth
- Department of Pharmacology, Addiction Science and Toxicology, The University of Tennessee-Health Sciences Center, Memphis, TN, United States.
| | - Mohammed M Nooh
- Department of Biochemistry, Faculty of Pharmacy Cairo University, Cairo, Egypt and Biochemistry Department, Faculty of Pharmacy, October 6 University, Giza, Egypt
| | - Salvatore Mancarella
- Department of Physiology, The University of Tennessee-Health Sciences Center, Memphis, TN, United States
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4
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Mikkelsen H, Vikse BE, Eikrem O, Scherer A, Finne K, Osman T, Marti HP. Glomerular proteomic profiling of kidney biopsies with hypertensive nephropathy reveals a signature of disease progression. Hypertens Res 2023; 46:144-156. [PMID: 36229534 DOI: 10.1038/s41440-022-01066-0] [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: 08/13/2022] [Revised: 09/11/2022] [Accepted: 09/26/2022] [Indexed: 02/03/2023]
Abstract
Hypertensive nephropathy (HN) requires a kidney biopsy as diagnostic gold-standard but histological findings are unspecific and specific prognostic markers are missing. We aimed at identifying candidate prognostic markers based on glomerular protein signatures. We studied adult patients (n = 17) with eGFR >30 ml/min/1.73m2 and proteinuria <3 g/d from the Norwegian Kidney Biopsy Registry, including subjects non progressing (NP, n = 9), or progressing (P, n = 8) to end-stage renal disease (ESRD) within an average follow-up of 22 years. Glomerular cross-sections from archival kidney biopsy sections were microdissected and processed for protein extraction. Proteomic analyses were performed using Q-exactive HF mass spectrometer and relative glomerular protein abundances were compared between P and NP patients. Immunohistochemistry (IHC) was used to validate selected data. Amongst 1870 quality filtered proteins, 58 were differentially expressed in P and NP patients' glomeruli, with absolute fold changes (FC) ≥1.5, p ≤ 0.05. Supervised classifier analysis (K nearest neighbor) identified a set of five proteins, including Gamma-butyrobetaine dioxygenase (BBOX1, O75936) and Cadherin 16 (CDH16, O75309), overexpressed in P, and Eosinophil peroxidase (EPX, P11678), DnaJ homolog subfamily B member 1 (DNAJB1, P25685) and Alpha-1-syntrophin (SNTA1, Q13424), overexpressed in NP glomeruli, correctly classifying 16/17 kidney biopsy samples. Geneset Enrichment Analysis (GSEA), showed that metabolic pathways were generally enriched in P, and structural cell pathways in NP. Pathway analysis identified Epithelial Adherens Junction Signaling as most affected canonical pathway. IHC analysis confirmed overexpression of BBOX1 and Cadherin 16 in glomeruli from P patients. In conclusion, glomerular proteomic profiling can be used to discriminate P from NP HN patients.
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Affiliation(s)
- Håvard Mikkelsen
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Bjørn E Vikse
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.,Department of Medicine, Haugesund Hospital, Haugesund, Norway
| | - Oystein Eikrem
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.,Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Andreas Scherer
- Spheromics, Kontiolahti, Finland.,Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland
| | - Kenneth Finne
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Tarig Osman
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Hans-Peter Marti
- Department of Clinical Medicine, University of Bergen, Bergen, Norway. .,Department of Medicine, Haukeland University Hospital, Bergen, Norway.
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5
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Evaluation of the dystrophin carboxy-terminal domain for micro-dystrophin gene therapy in cardiac and skeletal muscles in the DMD mdx rat model. Gene Ther 2022; 29:520-535. [PMID: 35105949 DOI: 10.1038/s41434-022-00317-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 12/09/2021] [Accepted: 01/13/2022] [Indexed: 01/02/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a muscle wasting disorder caused by mutations in the gene encoding dystrophin. Gene therapy using micro-dystrophin (MD) transgenes and recombinant adeno-associated virus (rAAV) vectors hold great promise. To overcome the limited packaging capacity of rAAV vectors, most MD do not include dystrophin carboxy-terminal (CT) domain. Yet, the CT domain is known to recruit α1- and β1-syntrophins and α-dystrobrevin, a part of the dystrophin-associated protein complex (DAPC), which is a signaling and structural mediator of muscle cells. In this study, we explored the impact of inclusion of the dystrophin CT domain on ΔR4-23/ΔCT MD (MD1), in DMDmdx rats, which allows for relevant evaluations at muscular and cardiac levels. We showed by LC-MS/MS that MD1 expression is sufficient to restore the interactions at a physiological level of most DAPC partners in skeletal and cardiac muscles, and that inclusion of the CT domain increases the recruitment of some DAPC partners at supra-physiological levels. In parallel, we demonstrated that inclusion of the CT domain does not improve MD1 therapeutic efficacy on DMD muscle and cardiac pathologies. Our work highlights new evidences of the therapeutic potential of MD1 and strengthens the relevance of this candidate for gene therapy of DMD.
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6
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Ivanušec A, Šribar J, Križaj I. Secreted Phospholipases A 2 - not just Enzymes: Revisited. Int J Biol Sci 2022; 18:873-888. [PMID: 35002531 PMCID: PMC8741859 DOI: 10.7150/ijbs.68093] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/02/2021] [Indexed: 12/18/2022] Open
Abstract
Secreted phospholipases A2 (sPLA2s) participate in a very broad spectrum of biological processes through their enzymatic activity and as ligands for membrane and soluble receptors. The physiological roles of sPLA2s as enzymes have been very well described, while their functions as ligands are still poorly known. Since the last overview of sPLA2-binding proteins (sPLA2-BPs) 10 years ago, several important discoveries have occurred in this area. New and more sensitive analytical tools have enabled the discovery of additional sPLA2-BPs, which are presented and critically discussed here. The structural diversity of sPLA2-BPs reveals sPLA2s as very promiscuous proteins, and we offer some structural explanations for this nature that makes these proteins evolutionarily highly advantageous. Three areas of physiological engagement of sPLA2-BPs have appeared most clearly: cellular transport and signalling, and regulation of the enzymatic activity of sPLA2s. Due to the multifunctionality of sPLA2s, they appear to be exceptional pharmacological targets. We reveal the potential to exploit interactions of sPLA2s with other proteins in medical terms, for the development of original diagnostic and therapeutic procedures. We conclude this survey by suggesting the priority questions that need to be answered.
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Affiliation(s)
- Adrijan Ivanušec
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.,Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | - Jernej Šribar
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Igor Križaj
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
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7
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Liang Y, Wang B, Chen S, Ye Z, Chai X, Li R, Li X, Kong G, Li Y, Zhang X, Che Z, Xie Q, Lian J, Lin B, Zhang X, Huang X, Huang W, Qiu X, Zeng J. Beta-1 syntrophin (SNTB1) regulates colorectal cancer progression and stemness via regulation of the Wnt/β-catenin signaling pathway. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:1016. [PMID: 34277816 PMCID: PMC8267293 DOI: 10.21037/atm-21-2700] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 06/15/2021] [Indexed: 12/31/2022]
Abstract
Background Beta-1 syntrophin (SNTB1) is an intracellular scaffold protein that provides a platform for the formation of signal transduction complexes, thereby modulating and coordinating various intracellular signaling events and crucial cellular processes. However, the physiological role of SNTB1 is poorly understood. This study aims to explore the role of SNTB1 in colorectal cancer (CRC) tumorigenesis and progression, with particular focus on SNTB1’s expression pattern, clinical relevance, and possible molecular mechanism in CRC development. Methods SNTB1 expression was analyzed in both clinical tissues and The Cancer Genome Atlas (TCGA) database. Real-time polymerase chain reaction (PCR), Western blot, and immunohistochemical assays were used to detect the relative mRNA and protein levels of SNTB1. Statistical analysis was performed to examine the correlation between SNTB1 expression and the clinicopathological characteristics of patients with CRC. Bioinformatics gene set enrichment analysis (GSEA), Western blot, luciferase assay, and agonist recovery assays were conducted to evaluate the relevance of SNTB1 and the β-catenin signaling pathway in CRC. A flow cytometry-based Hoechst 33342 efflux assay was applied to assess the proportion of the side population (SP) within total CRC cells. Results Elevated levels of SNTB1 were identified in CRC tissues and cell lines. The elevation of SNTB1 was positively correlated with the degree of malignancy and poor prognosis in CRC. We further revealed that, by modulating the β-catenin signaling pathway, silencing SNTB1 expression suppressed tumor growth and cancer stemness in vitro, as well as tumorigenesis in vivo. Conclusions These findings suggest that SNTB1 plays a crucial role in colorectal tumorigenesis and progression by modulating β-catenin signaling and the stemness maintenance of cancer cells.
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Affiliation(s)
- Yanfang Liang
- Department of Pathology, Dongguan Hospital Affiliated to Jinan University, Binhaiwan Central Hospital of Dongguan, Dongguan, China
| | - Bin Wang
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan Key Laboratory of Medical Bioactive Molecular Developmental and Translational Research, Guangdong Medical University, Dongguan, China
| | - Shasha Chen
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan Key Laboratory of Medical Bioactive Molecular Developmental and Translational Research, Guangdong Medical University, Dongguan, China.,Department of Clinical Laboratory, The Third People's Hospital of Shenzhen, Shenzhen, China
| | - Ziyu Ye
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan Key Laboratory of Medical Bioactive Molecular Developmental and Translational Research, Guangdong Medical University, Dongguan, China
| | - Xingxing Chai
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan Key Laboratory of Medical Bioactive Molecular Developmental and Translational Research, Guangdong Medical University, Dongguan, China.,Laboratory Animal Center, Guangdong Medical University, Zhanjiang, China
| | - Ronggang Li
- Department of Pathology, Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun Yat-sen University, Jiangmen, China
| | - Xiaoping Li
- Department of Gastrointestinal Surgery, Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun Yat-sen University, Jiangmen, China
| | - Gang Kong
- Department of Gastrointestinal Surgery, Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun Yat-sen University, Jiangmen, China
| | - Yanyun Li
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan Key Laboratory of Medical Bioactive Molecular Developmental and Translational Research, Guangdong Medical University, Dongguan, China
| | - Xueying Zhang
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan Key Laboratory of Medical Bioactive Molecular Developmental and Translational Research, Guangdong Medical University, Dongguan, China
| | - Zhengping Che
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan Key Laboratory of Medical Bioactive Molecular Developmental and Translational Research, Guangdong Medical University, Dongguan, China
| | - Qi Xie
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan Key Laboratory of Medical Bioactive Molecular Developmental and Translational Research, Guangdong Medical University, Dongguan, China
| | - Jiachun Lian
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan Key Laboratory of Medical Bioactive Molecular Developmental and Translational Research, Guangdong Medical University, Dongguan, China
| | - Bihua Lin
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan Key Laboratory of Medical Bioactive Molecular Developmental and Translational Research, Guangdong Medical University, Dongguan, China.,Clinical Experimental Center, Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun Yat-sen University, Jiangmen, China
| | - Xin Zhang
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan Key Laboratory of Medical Bioactive Molecular Developmental and Translational Research, Guangdong Medical University, Dongguan, China.,Clinical Experimental Center, Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun Yat-sen University, Jiangmen, China.,Collaborative Innovation Center for Antitumor Active Substance Research and Development, Guangdong Medical University, Zhanjiang, China
| | - Xueqin Huang
- Department of Otolaryngology Second School of Clinical College, Guangdong Medical University, Dongguan, China
| | - Weijuan Huang
- Department of Pharmacy, Dongguan Hospital Affiliated to Jinan University, Marina Bay Central Hospital of Dongguan, Dongguan, China
| | - Xianxiu Qiu
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan Key Laboratory of Medical Bioactive Molecular Developmental and Translational Research, Guangdong Medical University, Dongguan, China
| | - Jincheng Zeng
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan Key Laboratory of Medical Bioactive Molecular Developmental and Translational Research, Guangdong Medical University, Dongguan, China.,Collaborative Innovation Center for Antitumor Active Substance Research and Development, Guangdong Medical University, Zhanjiang, China.,Key Laboratory of Medical Bioactive Molecular Research for Department of Education of Guangdong Province, Guangdong Medical University, Dongguan, China
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8
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Moon JY, Kim HS. α-Syntrophin alleviates ER stress to maintain protein homeostasis during myoblast differentiation. FEBS Lett 2021; 595:1656-1670. [PMID: 33834492 DOI: 10.1002/1873-3468.14088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/02/2021] [Accepted: 03/17/2021] [Indexed: 12/12/2022]
Abstract
We have previously shown evidence that α-syntrophin plays an important role in myoblast differentiation. In this study, we focused on abnormal myotube formation of the α-syntrophin knockdown C2 cell line (SNKD). The overall amount of intracellular protein and muscle-specific proteins in SNKD cells were significantly lower than those in the control. Akt-mTOR signaling, an important pathway for protein synthesis and muscle hypertrophy, was downregulated. In addition, the levels of endoplasmic reticulum (ER) stress markers increased in SNKD cells. The decrease in intracellular protein synthesis and reduction in the myotube diameter in SNKD cells were restored by 4-phenylbutyric acid, a chemical chaperone, or overexpression of α-syntrophin. These results suggest a novel role for α-syntrophin in protein homeostasis during myoblast differentiation.
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Affiliation(s)
- Jae Yun Moon
- Department of Biological Science, Ajou University, Suwon, Korea
| | - Hye Sun Kim
- Department of Biological Science, Ajou University, Suwon, Korea
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9
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Alpha-syntrophin deficiency protects against non-alcoholic steatohepatitis associated increase of macrophages, CD8 + T-cells and galectin-3 in the liver. Exp Mol Pathol 2019; 113:104363. [PMID: 31881201 DOI: 10.1016/j.yexmp.2019.104363] [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: 11/28/2019] [Revised: 12/18/2019] [Accepted: 12/24/2019] [Indexed: 11/22/2022]
Abstract
Non-alcoholic steatohepatitis (NASH) is characterized by immune cell infiltration. Loss of the scaffold protein alpha-syntrophin (SNTA) protected mice from hepatic inflammation in the methionine-choline-deficient (MCD) diet model. Here, we determined increased numbers of macrophages and CD8+ T-cells in MCD diet induced NASH liver of wild type mice. In the mutant animals these NASH associated changes in immune cell composition were less pronounced. Further, there were more γδ T-cells in the NASH liver of the null mice. Galectin-3 protein in the hepatic non-parenchymal cell fraction was strongly induced in MCD diet fed wild type but not mutant mice. Antioxidant enzymes declined in NASH liver with no differences between the genotypes. To identify the target cells responsive to SNTA loss in-vitro experiments were performed. In the human hepatic stellate cell line LX-2, SNTA did not regulate pro-fibrotic or antioxidant proteins like alpha-smooth muscle actin or catalase. Soluble galectin-3 was, however, reduced upon SNTA knock-down and increased upon SNTA overexpression. SNTA deficiency neither affected cell proliferation nor cell death of LX-2 cells. In the macrophage cell line RAW264.7 low SNTA indeed caused higher galectin-3 production whereas release of TNF and cell viability were normal. Moreover, SNTA had no effect on hepatocyte chemerin and CCL2 expression. Overall, SNTA loss improved NASH without causing major effects in macrophage, hepatocyte and hepatic stellate cell lines. SNTA null mice fed the MCD diet had less body weight loss and this seems to contribute to improved liver health of the mutant mice.
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10
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Rao SB, Katoozi S, Skauli N, Froehner SC, Ottersen OP, Adams ME, Amiry-Moghaddam M. Targeted deletion of β1-syntrophin causes a loss of K ir 4.1 from Müller cell endfeet in mouse retina. Glia 2019; 67:1138-1149. [PMID: 30803043 DOI: 10.1002/glia.23600] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 01/23/2019] [Accepted: 01/24/2019] [Indexed: 02/02/2023]
Abstract
Proper function of the retina depends heavily on a specialized form of retinal glia called Müller cells. These cells carry out important homeostatic functions that are contingent on their polarized nature. Specifically, the Müller cell endfeet that contact retinal microvessels and the corpus vitreum show a tenfold higher concentration of the inwardly rectifying potassium channel Kir 4.1 than other Müller cell plasma membrane domains. This highly selective enrichment of Kir 4.1 allows K+ to be siphoned through endfoot membranes in a special form of spatial buffering. Here, we show that Kir 4.1 is enriched in endfoot membranes through an interaction with β1-syntrophin. Targeted disruption of this syntrophin caused a loss of Kir 4.1 from Müller cell endfeet without affecting the total level of Kir 4.1 expression in the retina. Targeted disruption of α1-syntrophin had no effect on Kir 4.1 localization. Our findings show that the Kir 4.1 aggregation that forms the basis for K+ siphoning depends on a specific syntrophin isoform that colocalizes with Kir 4.1 in Müller endfoot membranes.
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Affiliation(s)
- Shreyas B Rao
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Shirin Katoozi
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Nadia Skauli
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Stanley C Froehner
- Department of Physiology and Biophysics, University of Washington, Seattle, Western Australia
| | - Ole Petter Ottersen
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Marvin E Adams
- Department of Physiology and Biophysics, University of Washington, Seattle, Western Australia
| | - Mahmood Amiry-Moghaddam
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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11
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Ye R, Onodera T, Blanchard PG, Kusminski CM, Esser V, Brekken RA, Scherer PE. β1 Syntrophin Supports Autophagy Initiation and Protects against Cerulein-Induced Acute Pancreatitis. THE AMERICAN JOURNAL OF PATHOLOGY 2019; 189:813-825. [PMID: 30653956 DOI: 10.1016/j.ajpath.2019.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 12/26/2018] [Accepted: 01/02/2019] [Indexed: 01/23/2023]
Abstract
Syntrophins are a family of proteins forming membrane-anchored scaffolds and serving as adaptors for various transmembrane and intracellular signaling molecules. To understand the physiological roles of β1 syntrophin, one of the least characterized members, we generated mouse models to eliminate β1 syntrophin specifically in the endocrine or exocrine pancreas. β1 syntrophin is dispensable for the morphology and function of insulin-producing β cells. However, mice with β1 syntrophin deletion in exocrine acinar cells exhibit increased severity of cerulein-induced acute pancreatitis. Reduced expression of cystic fibrosis transmembrane conductance regulator and dilation of acinar lumen are potential predisposition factors. During the disease progression, a relative lack of autophagy is associated with deficiencies in both actin assembly and endoplasmic reticulum nucleation. Our findings reveal, for the first time, that β1 syntrophin is a critical regulator of actin cytoskeleton and autophagy in pancreatic acinar cells and is potently protective against cerulein-induced acute pancreatitis.
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Affiliation(s)
- Risheng Ye
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Medical Education, Texas Tech University Health Sciences Center Paul L. Foster School of Medicine, El Paso, Texas
| | - Toshiharu Onodera
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Pierre-Gilles Blanchard
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Christine M Kusminski
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Victoria Esser
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Rolf A Brekken
- Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Surgery, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.
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12
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Alpha-syntrophin dependent expression of tubulin alpha 8 protein in hepatocytes. J Physiol Biochem 2018; 74:511-521. [DOI: 10.1007/s13105-018-0645-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 07/11/2018] [Indexed: 12/13/2022]
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13
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The utrophin-beta 2 syntrophin complex regulates adipocyte lipid droplet size independent of adipogenesis. Mol Cell Biochem 2018; 452:29-39. [PMID: 30014220 DOI: 10.1007/s11010-018-3409-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 07/13/2018] [Indexed: 02/06/2023]
Abstract
Utrophin is a widely expressed cytoskeleton protein and is associated with lipid droplets (LDs) in adipocytes. The scaffold protein beta 2 syntrophin (SNTB2) controls signaling events by recruiting distinct membrane and cytoskeletal proteins, and binds to utrophin. Here we show that SNTB2 forms a complex with utrophin in adipocytes. SNTB2 protein is strongly diminished when utrophin is low. Of note, knock-down of utrophin or SNTB2 enhances LD growth during adipogenesis. SNTB2 reduction has no effect on basal and induced lipolysis, and insulin-stimulated phosphorylation of Akt is normal. The antilipolytic activity of insulin is enhanced in adipocytes with low SNTB2, while knock-down of utrophin has no effect. Uptake of exogenously supplied oleate and linoleate is comparable in scrambled and SNTB2 siRNA-treated cells. In the fibroblasts, diminished SNTB2 is associated with lower proliferation. CCAAT/enhancer-binding protein alpha and sterol regulatory element-binding proteins which are critical transcription factors for adipogenesis are normally expressed. Consequently, maturation of cells with SNTB2 knock-down is not grossly impaired. In fibroblasts, SNTB2 is localized to filamentous and vesicular structures which are distinct from beta actin, alpha tubulin, endoplasmic reticulum, early endosomes, lysosomes and mitochondria. Collectively, our data provide evidence that the utrophin-SNTB2 complex regulates LD size without affecting adipogenesis.
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Eisinger K, Rein-Fischboeck L, Neumeier M, Schmidhofer S, Pohl R, Haberl EM, Liebisch G, Kopp A, Schmid A, Krautbauer S, Buechler C. Alpha-syntrophin deficient mice are protected from adipocyte hypertrophy and ectopic triglyceride deposition in obesity. Exp Mol Pathol 2018; 104:212-221. [DOI: 10.1016/j.yexmp.2018.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 04/12/2018] [Accepted: 04/23/2018] [Indexed: 12/20/2022]
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15
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Leyva-Leyva M, Sandoval A, Felix R, González-Ramírez R. Biochemical and Functional Interplay Between Ion Channels and the Components of the Dystrophin-Associated Glycoprotein Complex. J Membr Biol 2018; 251:535-550. [PMID: 29779049 DOI: 10.1007/s00232-018-0036-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 05/09/2018] [Indexed: 12/19/2022]
Abstract
Dystrophin is a cytoskeleton-linked membrane protein that binds to a larger multiprotein assembly called the dystrophin-associated glycoprotein complex (DGC). The deficiency of dystrophin or the components of the DGC results in the loss of connection between the cytoskeleton and the extracellular matrix with significant pathophysiological implications in skeletal and cardiac muscle as well as in the nervous system. Although the DGC plays an important role in maintaining membrane stability, it can also be considered as a versatile and flexible molecular complex that contribute to the cellular organization and dynamics of a variety of proteins at specific locations in the plasma membrane. This review deals with the role of the DGC in transmembrane signaling by forming supramolecular assemblies for regulating ion channel localization and activity. These interactions are relevant for cell homeostasis, and its alterations may play a significant role in the etiology and pathogenesis of various disorders affecting muscle and nerve function.
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Affiliation(s)
- Margarita Leyva-Leyva
- Department of Molecular Biology and Histocompatibility, "Dr. Manuel Gea González" General Hospital, Mexico City, Mexico
| | - Alejandro Sandoval
- Faculty of Superior Studies Iztacala, National Autonomous University of Mexico (UNAM), Tlalnepantla, Mexico
| | - Ricardo Felix
- Department of Cell Biology, Center for Research and Advanced Studies of the National Polytechnic Institute (Cinvestav-IPN), Mexico City, Mexico.
| | - Ricardo González-Ramírez
- Department of Molecular Biology and Histocompatibility, "Dr. Manuel Gea González" General Hospital, Mexico City, Mexico.
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Sifi M, Benabdesselam R, Souttou S, Annese T, Rendon A, Nico B, Dorbani-Mamine L. Dystrophin 71 and α1syntrophin in morpho-functional plasticity of rat supraoptic nuclei: Effect of saline surcharge and reversibly normal hydration. Acta Histochem 2018; 120:187-195. [PMID: 29395317 DOI: 10.1016/j.acthis.2018.01.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 12/25/2017] [Accepted: 01/09/2018] [Indexed: 02/02/2023]
Abstract
Dystrophin (Dp) is a multidomain protein that links the actin cytoskeleton to the extracellular matrix through the dystrophin associated proteins complex (DAPC). Dp of 71 kDa (Dp71), corresponding to the COOH-terminal domain of dystrophin, and α1-syntrophin (α1Syn) as the principal component of the DAPC, are strongly expressed in the brain. To clarify their involvement in the central control of osmotic homeostasis, we investigated the effect of 14 days of salt loading (with drinking water containing 2% NaCl) and then reversibly to 30 days of normal hydration (with drinking water without salt), first on the expression by western-blotting and the distribution by immunochemistry of Dp71 and α1Syn in the SON of the rat and, second, on the level of some physiological parameters, as the plasma osmolality, natremia and hematocrit. Dp71 is the most abundant form of dystrophin revealed in the supraoptic nucleu (SON) of control rat. Dp71 was localized in magnocellular neurons (MCNs) and astrocytes, when α1Syn was observed essentially in astrocytes end feet. After 14 days of salt-loading, Dp71 and α1Syn signals decreased and a dual signal for these two proteins was revealed in the astrocytes processes SON surrounding blood capillaries. In addition, salt loading leads to an increase in plasma osmolality, natremia and hematocrit. Reversibly, after 30 days of normal hydration, the intensity of the signal for the two proteins, Dp71 and α1Syn, increased and approached that of control. Furtheremore, the levels of the physiological parameters decreased and approximated those of control. This suggests that Dp71 and α1Syn may be involved in the functional activity of the SON. Their localization in astrocyte end feet emphasizes their importance in neuronal-vascular-astrocyte interactions for the central detection of osmolality. In the SON, Dp71 and α1Syn may be involved in osmosensitivity.
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Affiliation(s)
- Madina Sifi
- Equipe de Neurochimie, LBPO, Faculté des Sciences Biologiques, USTHB, Alger, Algeria
| | - Roza Benabdesselam
- Equipe de Neurochimie, LBPO, Faculté des Sciences Biologiques, USTHB, Alger, Algeria; Département de Biologie, Faculté des Sciences Biologiques et Agronomiques, UMMTO, Tizi Ouzou, Algeria.
| | - Sabrina Souttou
- Equipe de Neurochimie, LBPO, Faculté des Sciences Biologiques, USTHB, Alger, Algeria
| | - Tiziana Annese
- Department of Basic Medical Sciences, Neurosciences and Sensory Organes, University of Bari "Aldo Moro", Bari, Italy
| | - Alvaro Rendon
- Laboratoire de Physiopathologie Cellulaire et Moleculaire de la Retine, INSERM UMRS-592, Institut de la Vision, Paris, France
| | - Beatrice Nico
- Department of Basic Medical Sciences, Neurosciences and Sensory Organes, University of Bari "Aldo Moro", Bari, Italy
| | - Latifa Dorbani-Mamine
- Equipe de Neurochimie, LBPO, Faculté des Sciences Biologiques, USTHB, Alger, Algeria
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Rein-Fischboeck L, Haberl EM, Pohl R, Schmid V, Feder S, Krautbauer S, Liebisch G, Buechler C. Alpha-syntrophin null mice are protected from non-alcoholic steatohepatitis in the methionine-choline-deficient diet model but not the atherogenic diet model. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:526-537. [PMID: 29474931 DOI: 10.1016/j.bbalip.2018.02.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 01/23/2018] [Accepted: 02/17/2018] [Indexed: 12/13/2022]
Abstract
Adipose tissue dysfunction contributes to the pathogenesis of non-alcoholic steatohepatitis (NASH). The adapter protein alpha-syntrophin (SNTA) is expressed in adipocytes. Knock-down of SNTA increases preadipocyte proliferation and formation of small lipid droplets, which are both characteristics of healthy adipose tissue. To elucidate a potential protective role of SNTA in NASH, SNTA null mice were fed a methionine-choline-deficient (MCD) diet or an atherogenic diet which are widely used as preclinical NASH models. MCD diet mediated loss of fat mass was largely improved in SNTA-/- mice compared to the respective wild type animals. Hepatic lipids were mostly unchanged while the oxidative stress marker malondialdehyde was only induced in the wild type mice. The expression of inflammatory markers and macrophage immigration into the liver were reduced in SNTA-/- animals. This protective function of SNTA loss was absent in atherogenic diet induced NASH. Here, hepatic expression of inflammatory and fibrotic genes was similar in both genotypes though mutant mice gained less body fat during feeding. Hepatic cholesterol and ceramide were strongly induced in both strains upon feeding the atherogenic diet, while hepatic sphingomyelin, phosphatidylserine and phosphatidylethanolamine levels were suppressed. SNTA deficient mice are protected from fat loss and NASH in the experimental MCD model. NASH induced by an atherogenic diet is not influenced by loss of SNTA. The present study suggests the use of different experimental NASH models to study the pathophysiological role of proteins like SNTA in NASH.
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Affiliation(s)
- Lisa Rein-Fischboeck
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Elisabeth M Haberl
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Rebekka Pohl
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Verena Schmid
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Susanne Feder
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Sabrina Krautbauer
- Institute of Clinical Chemistry and Laboratory Medicine, Regensburg University Hospital, Regensburg, Germany
| | - Gerhard Liebisch
- Institute of Clinical Chemistry and Laboratory Medicine, Regensburg University Hospital, Regensburg, Germany
| | - Christa Buechler
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany.
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18
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Rein-Fischboeck L, Pohl R, Haberl EM, Weiss TS, Buechler C. The adaptor protein alpha-syntrophin is reduced in human non-alcoholic steatohepatitis but is unchanged in hepatocellular carcinoma. Exp Mol Pathol 2017; 103:204-209. [DOI: 10.1016/j.yexmp.2017.09.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 09/19/2017] [Indexed: 12/19/2022]
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19
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Dp71 is regulated by phosphorylation and ubiquitin-proteasome system in neuronal cells. Biochem Biophys Res Commun 2017; 492:349-355. [PMID: 28851655 DOI: 10.1016/j.bbrc.2017.08.108] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 08/26/2017] [Indexed: 01/29/2023]
Abstract
The Dystrophin (Dp) gene is responsible for Duchenne muscular dystrophy (DMD), which is characterized by progressive muscular degeneration and variable degrees of cognitive impairment. Although Dp71 is the most abundant among the Dp isoforms in the brain, the regulatory mechanisms of the related expression levels have not been elucidated. In this study, we found that the constitutive expression levels of Dp71 in PC12 cells were sensitive to proteasomal inhibition. The ectopic expression of FLAG-tagged ubiquitin revealed that Dp71 was ubiquitinated intracellularly. Interestingly, proteasomal inhibition was accompanied by a posttranslational accumulation of modified Dp71, which was restored by protein phosphatase treatment in vitro, indicating that phosphorylation is responsible for the modification and affects the proteasome-dependent degradation of Dp71. Proteasomal activity-sensitive phosphorylated Dp71 is closely associated with syntrophin, a well-known binding partner of Dp71, and syntrophin is also regulated by proteasomal activity in a similar way to Dp71, suggesting that the posttranslational regulatory machinery for Dp71 level is coupled with Dp71-syntrophin molecular complex. Taken together, our results indicated that the expression levels of Dp71 are posttranslationally regulated by the phosphorylation-ubiquitin-proteasomal pathway, which may indicate the presence of regulatory mechanisms underlying the proteostasis of both Dp and its molecular complex, which may lead to better therapeutic approaches for the treatment of Dp-related diseases.
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Costas-Insua C, Merino-Gracia J, Aicart-Ramos C, Rodríguez-Crespo I. Subcellular Targeting of Nitric Oxide Synthases Mediated by Their N-Terminal Motifs. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2017; 111:165-195. [PMID: 29459031 DOI: 10.1016/bs.apcsb.2017.07.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
From a catalytic point of view, the three mammalian nitric oxide synthases (NOSs) function in an almost identical way. The N-terminal oxygenase domain catalyzes the conversion of l-arginine to l-citrulline plus ·NO in two sequential oxidation steps. Once l-arginine binds to the active site positioned above the heme moiety, two consecutive monooxygenation reactions take place. In the first step, l-arginine is hydroxylated to make Nω-hydroxy-l-arginine in a process that requires 1 molecule of NADPH and 1 molecule of O2 per mol of l-arginine reacted. In the second step, Nω-hydroxy-l-arginine, never leaving the active site, is oxidized to ·NO plus l-citrulline and 1 molecule of O2 and 0.5 molecules of NADPH are consumed. Since nitric oxide is an important signaling molecule that participates in a number of biological processes, including neurotransmission, vasodilation, and immune response, synthesis and release of ·NO in vivo must be exquisitely regulated both in time and in space. Hence, NOSs have evolved introducing in their amino acid sequences subcellular targeting motifs, most of them located at their N-termini. Deletion studies performed on recombinant, purified NOSs have revealed that part of the N-terminus of all three NOS can be eliminated with the resulting mutant enzymes still being catalytically active. Likewise, NOS isoforms lacking part of their N-terminus when transfected in cells render mislocalized, active proteins. In this review we will comment on the current knowledge of these subcellular targeting signals present in nNOS, iNOS, and eNOS.
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Temporal Profiling of Astrocyte Precursors Reveals Parallel Roles for Asef during Development and after Injury. J Neurosci 2017; 36:11904-11917. [PMID: 27881777 DOI: 10.1523/jneurosci.1658-16.2016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 09/12/2016] [Accepted: 09/18/2016] [Indexed: 12/21/2022] Open
Abstract
Lineage development is a stepwise process, governed by stage-specific regulatory factors and associated markers. Astrocytes are one of the principle cell types in the CNS and the stages associated with their development remain very poorly defined. To identify these stages, we performed gene-expression profiling on astrocyte precursor populations in the spinal cord, identifying distinct patterns of gene induction during their development that are strongly correlated with human astrocytes. Validation studies identified a new cohort of astrocyte-associated genes during development and demonstrated their expression in reactive astrocytes in human white matter injury (WMI). Functional studies on one of these genes revealed that mice lacking Asef exhibited impaired astrocyte differentiation during development and repair after WMI, coupled with compromised blood-brain barrier integrity in the adult CNS. These studies have identified distinct stages of astrocyte lineage development associated with human WMI and, together with our functional analysis of Asef, highlight the parallels between astrocyte development and their reactive counterparts associated with injury. SIGNIFICANCE STATEMENT Astrocytes play a central role in CNS function and associated diseases. Yet the mechanisms that control their development remain poorly defined. Using the developing mouse spinal cord as a model system, we identify molecular changes that occur in developing astrocytes. These molecular signatures are strongly correlated with human astrocyte expression profiles and validation in mouse spinal cord identifies a host of new genes associated with the astrocyte lineage. These genes are present in reactive astrocytes in human white matter injury, and functional studies reveal that one of these genes, Asef, contributes to reactive astrocyte responses after injury. These studies identify distinct stages of astrocyte lineage development and highlight the parallels between astrocyte development and their reactive counterparts associated with injury.
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Moon JY, Choi SJ, Heo CH, Kim HM, Kim HS. α-Syntrophin stabilizes catalase to reduce endogenous reactive oxygen species levels during myoblast differentiation. FEBS J 2017; 284:2052-2065. [DOI: 10.1111/febs.14103] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 04/27/2017] [Accepted: 05/05/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Jae Yun Moon
- Department of Biological Science; College of Natural Sciences; Ajou University; Suwon Korea
| | - Su Jin Choi
- Department of Biological Science; College of Natural Sciences; Ajou University; Suwon Korea
| | - Cheol Ho Heo
- Departments of Chemistry and Energy Systems Research; Ajou University; Suwon Korea
| | - Hwan Myung Kim
- Departments of Chemistry and Energy Systems Research; Ajou University; Suwon Korea
| | - Hye Sun Kim
- Department of Biological Science; College of Natural Sciences; Ajou University; Suwon Korea
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Dystrophin Dp71 Isoforms Are Differentially Expressed in the Mouse Brain and Retina: Report of New Alternative Splicing and a Novel Nomenclature for Dp71 Isoforms. Mol Neurobiol 2017; 55:1376-1386. [PMID: 28127699 DOI: 10.1007/s12035-017-0405-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 01/12/2017] [Indexed: 12/27/2022]
Abstract
Multiple dystrophin Dp71 isoforms have been identified in rats, mice, and humans and in several cell line models. These Dp71 isoforms are produced by the alternative splicing of exons 71 to 74 and 78 and intron 77. Three main groups of Dp71 proteins are defined based on their C-terminal specificities: Dp71d, Dp71f, and Dp71e. Dp71 is highly expressed in the brain and retina; however, the specific isoforms present in these tissues have not been determined to date. In this work, we explored the expression of Dp71 isoforms in the mouse brain and retina using RT-PCR assays followed by the cloning of PCR products into the pGEM-T Easy vector, which was used to transform DH5α cells. Dp71-positive colonies were later analyzed by PCR multiplex and DNA sequencing to determine the alternative splicing. We thus demonstrated the expression of Dp71 transcripts corresponding to Dp71, Dp71a, Dp71c, Dp71b, Dp71ab, Dp71 Δ110, and novel Dp71 isoforms spliced in exon 74; 71 and 74; 71, 73 and 74; and 74 and 78, which we named Dp71d Δ74 , Dp71d Δ71,74 , Dp71d Δ71,73-74 , and Dp71f Δ74 , respectively. Additionally, we demonstrated that the Dp71d group of isoforms is highly expressed in the brain, while the Dp71f group predominates in the retina, at both the cDNA and protein levels. These findings suggest that distinct Dp71 isoforms may play different roles in the brain and retina.
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The adaptor protein alpha-syntrophin regulates adipocyte lipid droplet growth. Exp Cell Res 2016; 345:100-7. [DOI: 10.1016/j.yexcr.2016.05.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 05/04/2016] [Accepted: 05/25/2016] [Indexed: 12/15/2022]
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25
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Actin depolymerization mediated loss of SNTA1 phosphorylation and Rac1 activity has implications on ROS production, cell migration and apoptosis. Apoptosis 2016; 21:737-48. [DOI: 10.1007/s10495-016-1241-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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26
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α1-Syntrophin Variant Identified in Drug-Induced Long QT Syndrome Increases Late Sodium Current. PLoS One 2016; 11:e0152355. [PMID: 27028743 PMCID: PMC4814026 DOI: 10.1371/journal.pone.0152355] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 03/14/2016] [Indexed: 12/19/2022] Open
Abstract
Drug-induced long-QT syndrome (diLQTS) is often due to drug block of IKr, especially in genetically susceptible patients with subclinical mutations in the IKr-encoding KCHN2. Few variants in the cardiac NaV1.5 Na+ channel complex have been associated with diLQTS. We tested whether a novel SNTA1 (α1-syntrophin) variant (p.E409Q) found in a patient with diLQTS increases late sodium current (INa-L), thereby providing a disease mechanism. Electrophysiological studies were performed in HEK293T cells co-expressing human NaV1.5/nNOS/PMCA4b with either wild type (WT) or SNTA1 variants (A390V-previously reported in congenital LQTS; and E409Q); and in adult rat ventricular cardiomyocytes infected with SNTA1 expressing adenoviruses (WT or one of the two SNTA1 variants). In HEK293T cells and in cardiomyocytes, there was no significant difference in the peak INa densities among the SNTA1 WT and variants. However, both variants increased INa-L (% of peak current) in HEK293T cells (0.58±0.10 in WT vs. 0.90±0.11 in A390V, p = 0.048; vs. 0.88±0.07 in E409Q, p = 0.023). In cardiomyocytes, INa-L was significantly increased by E409Q, but not by A390V compared to WT (0.49±0.14 in WT vs.0.94±0.23 in A390V, p = 0.099; vs. 1.12±0.24 in E409Q, p = 0.019). We demonstrated that a novel SNTA1 variant is likely causative for diLQTS by augmenting INa-L. These data suggest that variants within the NaV1.5-interacting α1-syntrophin are a potential mechanism for diLQTS, thereby expanding the concept that variants within congenital LQTS loci can cause diLQTS.
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Constantin B. Role of Scaffolding Proteins in the Regulation of TRPC-Dependent Calcium Entry. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:379-403. [PMID: 27161237 DOI: 10.1007/978-3-319-26974-0_16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
Abstract
Plasma membrane ion channels, and in particular TRPC channels need a specific membrane environment and association with scaffolding, signaling, and cytoskeleton proteins in order to play their important functional role. The molecular composition of TRPC channels is an important factor in determining channel activation mechanisms. TRPC proteins are incorporated in macromolecular complexes including several key Ca(2 +) signaling proteins as well as proteins involved in vesicle trafficking, cytoskeletal interactions, and scaffolding. Evidence has been provided for association of TRPC with calmodulin (CaM), IP3R, PMCA, Gq/11, RhoA, and a variety of scaffolding proteins. The interaction between TRPC channels with adaptor proteins, determines their mode of regulation as well as their cellular localization and function. Adaptor proteins do not display any enzymatic activity but act as scaffold for the building of signaling complexes. The scaffolding proteins are involved in the assembling of these Ca(2+) signaling complexes, the correct sub-cellular localization of protein partners, and the regulation of the TRPC channelosome. In particular, these proteins, via their multiple protein-protein interaction motifs, can interact with various ion channels involved in the transmembrane potential, and membrane excitability. Scaffolding proteins are key components for the functional organization of TRPC channelosomes that serves as a platform regulating slow Ca(2+) entry, spatially and temporally controlled [Ca(2+)]i signals and Ca(2+) -dependent cellular functions.
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Affiliation(s)
- Bruno Constantin
- Laboratory STIM, ERL-7368 CNRS-Université de Poitiers, 1, rue Georges Bonnet, Bat. B36, Pôle Biologie-Santé, 86000, Poitiers, France.
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Abstract
Muscle fibres are very specialised cells with a complex structure that requires a high level of organisation of the constituent proteins. For muscle contraction to function properly, there is a need for not only sarcomeres, the contractile structures of the muscle fibre, but also costameres. These are supramolecular structures associated with the sarcolemma that allow muscle adhesion to the extracellular matrix. They are composed of protein complexes that interact and whose functions include maintaining cell structure and signal transduction mediated by their constituent proteins. It is important to improve our understanding of these structures, as mutations in various genes that code for costamere proteins cause many types of muscular dystrophy. In this review, we provide a description of costameres detailing each of their constituent proteins, such as dystrophin, dystrobrevin, syntrophin, sarcoglycans, dystroglycans, vinculin, talin, integrins, desmin, plectin, etc. We describe as well the diseases associated with deficiency thereof, providing a general overview of their importance.
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Eisinger K, Froehner SC, Adams ME, Krautbauer S, Buechler C. Evaluation of the specificity of four commercially available antibodies to alpha-syntrophin. Anal Biochem 2015; 484:99-101. [PMID: 26079703 DOI: 10.1016/j.ab.2015.06.012] [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: 11/06/2014] [Revised: 04/07/2015] [Accepted: 06/02/2015] [Indexed: 12/17/2022]
Abstract
Alpha-syntrophin (SNTA) is an adaptor protein that regulates several signaling pathways. To analyze expression of SNTA immunoblot assays must be performed. Here, the specificity of four commercially available SNTA antibodies has been evaluated in immunoblot experiments using liver tissues of wild-type and SNTA-deficient mice. While one of the antibodies reacts with SNTA, two antibodies specifically recognize beta 2 syntrophin (SNTB2). The antigen detected by the fourth antibody has not been identified but is different from SNTA and SNTB2. Therefore, only one of the four tested antibodies is appropriate to analyze SNTA protein levels by immunoblot.
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Affiliation(s)
- Kristina Eisinger
- Department of Internal Medicine I, University Hospital of Regensburg, 93042 Regensburg, Germany
| | - Stanley C Froehner
- Department of Physiology and Biophysics, University of Washington, WA, USA
| | - Marvin E Adams
- Department of Physiology and Biophysics, University of Washington, WA, USA
| | - Sabrina Krautbauer
- Department of Internal Medicine I, University Hospital of Regensburg, 93042 Regensburg, Germany
| | - Christa Buechler
- Department of Internal Medicine I, University Hospital of Regensburg, 93042 Regensburg, Germany.
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Hebel T, Eisinger K, Neumeier M, Rein-Fischboeck L, Pohl R, Meier EM, Boettcher A, Froehner SC, Adams ME, Liebisch G, Krautbauer S, Buechler C. Lipid abnormalities in alpha/beta2-syntrophin null mice are independent from ABCA1. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:527-36. [PMID: 25625330 DOI: 10.1016/j.bbalip.2015.01.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 01/12/2015] [Accepted: 01/19/2015] [Indexed: 01/27/2023]
Abstract
The syntrophins alpha (SNTA) and beta 2 (SNTB2) are molecular adaptor proteins shown to stabilize ABCA1, an essential regulator of HDL cholesterol. Furthermore, SNTB2 is involved in glucose stimulated insulin release. Hyperglycemia and dyslipidemia are characteristic features of the metabolic syndrome, a serious public health problem with rising prevalence. Therefore, it is important to understand the role of the syntrophins herein. Mice deficient for both syntrophins (SNTA/B2-/-) have normal insulin and glucose tolerance, hepatic ABCA1 protein and cholesterol. When challenged with a HFD, wild type and SNTA/B2-/- mice have similar weight gain, adiposity, serum and liver triglycerides. Hepatic ABCA1, serum insulin and insulin sensitivity are normal while glucose tolerance is impaired. Liver cholesterol is reduced, and expression of SREBP2 and HMG-CoA-R is increased in the knockout mice. Scavenger receptor-BI (SR-BI) protein is strongly diminished in the liver of SNTA/B2-/- mice while SR-BI binding protein NHERF1 is not changed and PDZK1 is even induced. Knock-down of SNTA, SNTB2 or both has no effect on hepatocyte SR-BI and PDZK1 proteins. Further, SR-BI levels are not reduced in brown adipose tissue of SNTA/B2-/- mice excluding that syntrophins directly stabilize SR-BI. SR-BI stability is regulated by MAPK and phosphorylated ERK2 is induced in the liver of the knock-out mice. Blockage of ERK activity upregulates hepatocyte SR-BI showing that increased MAPK activity contributes to low SR-BI. Sphingomyelin which is well described to regulate cholesterol metabolism is reduced in the liver and serum of the knock-out mice while the size of serum lipoproteins is not affected. Current data exclude a major function of these syntrophins in ABCA1 activity and insulin release but suggest a role in regulating glucose uptake, ERK and SR-BI levels, and sphingomyelin metabolism in obesity.
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Affiliation(s)
- Tobias Hebel
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Kristina Eisinger
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Markus Neumeier
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Lisa Rein-Fischboeck
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Rebekka Pohl
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Elisabeth M Meier
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Alfred Boettcher
- Institute for Clinical Chemistry and Laboratory Medicine, Regensburg University Hospital, Regensburg, Germany
| | - Stanley C Froehner
- Department of Physiology and Biophysics, University of Washington, WA, USA
| | - Marvin E Adams
- Department of Physiology and Biophysics, University of Washington, WA, USA
| | - Gerhard Liebisch
- Institute for Clinical Chemistry and Laboratory Medicine, Regensburg University Hospital, Regensburg, Germany
| | - Sabrina Krautbauer
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Christa Buechler
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany.
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García-Pelagio KP, Muriel J, O'Neill A, Desmond PF, Lovering RM, Lund L, Bond M, Bloch RJ. Myopathic changes in murine skeletal muscle lacking synemin. Am J Physiol Cell Physiol 2015; 308:C448-62. [PMID: 25567810 DOI: 10.1152/ajpcell.00331.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Diseases of striated muscle linked to intermediate filament (IF) proteins are associated with defects in the organization of the contractile apparatus and its links to costameres, which connect the sarcomeres to the cell membrane. Here we study the role in skeletal muscle of synemin, a type IV IF protein, by examining mice null for synemin (synm-null). Synm-null mice have a mild skeletal muscle phenotype. Tibialis anterior (TA) muscles show a significant decrease in mean fiber diameter, a decrease in twitch and tetanic force, and an increase in susceptibility to injury caused by lengthening contractions. Organization of proteins associated with the contractile apparatus and costameres is not significantly altered in the synm-null. Elastimetry of the sarcolemma and associated contractile apparatus in extensor digitorum longus myofibers reveals a reduction in tension consistent with an increase in sarcolemmal deformability. Although fatigue after repeated isometric contractions is more marked in TA muscles of synm-null mice, the ability of the mice to run uphill on a treadmill is similar to controls. Our results suggest that synemin contributes to linkage between costameres and the contractile apparatus and that the absence of synemin results in decreased fiber size and increased sarcolemmal deformability and susceptibility to injury. Thus synemin plays a moderate but distinct role in fast twitch skeletal muscle.
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Affiliation(s)
- Karla P García-Pelagio
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, Maryland
| | - Joaquin Muriel
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, Maryland
| | - Andrea O'Neill
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, Maryland
| | - Patrick F Desmond
- Program in Biochemistry and Molecular Biology, School of Medicine, University of Maryland, Baltimore, Maryland
| | - Richard M Lovering
- Department of Orthopaedics, School of Medicine, University of Maryland, Baltimore, Maryland
| | - Linda Lund
- Merrick School of Business, University of Baltimore, Baltimore, Maryland; and
| | - Meredith Bond
- College of Sciences and Health Professions, Cleveland State University, Cleveland, Ohio
| | - Robert J Bloch
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, Maryland;
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Abstract
Sodium current in the heart flows principally through the pore protein NaV1.5, which is part of a complex of interacting proteins that serve both to target and localize the complex in the membrane, and to modulate function by such post-translational modifications as phosphorylation and nitrosylation. Multiple mutations in seven different NaV1.5 interacting proteins have been associated with dysfunctional sodium current and inherited cardiac diseases, including long QT syndrome, Brugada syndrome, atrial fibrillation, and cardiomyopathy, as well as sudden infant death syndrome (SIDS). Mutations in as yet unidentified interacting proteins may account for cardiac disease for which a genetic basis has not yet been established. Characterizing the mechanisms by which these mutations cause disease may give insight into etiologies and treatments of more common acquired cardiac disease, such as ischemia and heart failure.
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Affiliation(s)
- John W Kyle
- Department of Medicine, Division of Cardiovascular Medicine, University of Wisconsin, Madison, Wisconsin, USA 53792
| | - Jonathan C Makielski
- Department of Medicine, Division of Cardiovascular Medicine, University of Wisconsin, Madison, Wisconsin, USA 53792
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Lee HJ, Kwon MH, Lee S, Hall RA, Yun CC, Choi I. Systematic family-wide analysis of sodium bicarbonate cotransporter NBCn1/SLC4A7 interactions with PDZ scaffold proteins. Physiol Rep 2014; 2:2/5/e12016. [PMID: 24844638 PMCID: PMC4098744 DOI: 10.14814/phy2.12016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
NBCn1 (SLC4A7) plays a role in transepithelial HCO3 (-) movement and intracellular pH maintenance in many tissues. In this study, we searched PDZ proteins capable of binding to NBCn1. We screened a protein array membrane, on which 96 different class I PDZ protein peptides were blotted, with the C-terminal domain of NBCn1 fused to GST. Thirteen proteins were identified in these screens: MAGI-3, NHERF-1, NHERF-2, PSD-95, chapsyn-110, ERBIN, MALS-1, densin-180, syntrophins α1, β2, γ2, MUPP1, and PDZK1. After determining these binding partners, we analyzed the database of known and predicted protein interactions to obtain an NBCn1 interaction network. The network shows NBCn1 being physically and functionally associated with a variety of membrane and cytosolic proteins via the binding partners. We then focused on syntrophin γ2 to examine the molecular and functional interaction between NBCn1 and one of the identified binding partners in the Xenopus oocyte expression system. GST/NBCn1 pulled down syntrophin γ2 and conversely GST/syntrophin γ2 pulled down NBCn1. Moreover, syntrophin γ2 increased intracellular pH recovery, from acidification, mediated by NBCn1's Na/HCO3 cotransport. Syntrophin γ2 also increased an ionic conductance produced by NBCn1 channel-like activity. Thus, syntrophin γ2 regulates NBCn1 activity. In conclusion, this study demonstrates that NBCn1 binds to many PDZ proteins, which in turn may allow the transporter to associate with other physiologically important proteins.
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Affiliation(s)
- Hye Jeong Lee
- Department of Pediatrics, Division of Hematology and Oncology, Vanderbilt University, Nashville, Tennessee, USA
| | - Min Hyung Kwon
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Soojung Lee
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Randy A Hall
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - C Chris Yun
- Department of Medicine, Division of Digestive Disease, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Inyeong Choi
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia, USA
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Bhat HF, Baba RA, Adams ME, Khanday FA. Role of SNTA1 in Rac1 activation, modulation of ROS generation, and migratory potential of human breast cancer cells. Br J Cancer 2014; 110:706-14. [PMID: 24434436 PMCID: PMC3915110 DOI: 10.1038/bjc.2013.723] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 10/19/2013] [Accepted: 10/22/2013] [Indexed: 12/29/2022] Open
Abstract
Background: Alpha-1-syntrophin (SNTA1) has been implicated in the activation of Rac1. However, the underlying mechanism has not yet been explored. Here, we show that a novel complex, involving SNTA1, P66shc, and Grb2 proteins, is involved in Rac1 activation. Methods: Co-immunoprecipitation assays were used to show the complex formation, while siRNAs and shRNAs were used to downregulate expression of these proteins. Various Rac1 activation assays and functional assays, such as migration assays, in vitro wound healing assays, cell proliferation assays, and ROS generation assays, were also performed. Results: The results showed a significant increase in activation of Rac1 when SNTA1 and P66shc were overexpressed, whereas depletion of SNTA1 and P66shc expression effectively reduced the levels of active Rac1. The results indicated a significant displacement of Sos1 protein from Grb2 when SNTA1 and P66shc are overexpressed in breast cancer cell lines, resulting in Sos1 predominantly forming a complex with Eps8 and E3b1. In addition, the SNTA1/P66shc-mediated Rac1 activation resulted in an increase in reactive oxygen species (ROS) production and migratory potential in human breast cancer cells. Conclusion: Together, our results present a possible mechanism of Rac1 activation involving SNTA1 and emphasise its role in ROS generation, cell migration, and acquisition of malignancy.
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Affiliation(s)
- H F Bhat
- Department of Biotechnology, University of Kashmir, Jammu and Kashmir, India
| | - R A Baba
- Department of Biotechnology, University of Kashmir, Jammu and Kashmir, India
| | - M E Adams
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
| | - F A Khanday
- Department of Biotechnology, University of Kashmir, Jammu and Kashmir, India
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Im CN, Kim BM, Moon EY, Hong DW, Park JW, Hong SH. Characterization of H460R, a Radioresistant Human Lung Cancer Cell Line, and Involvement of Syntrophin Beta 2 (SNTB2) in Radioresistance. Genomics Inform 2013; 11:245-53. [PMID: 24465237 PMCID: PMC3897853 DOI: 10.5808/gi.2013.11.4.245] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 11/16/2013] [Accepted: 11/18/2013] [Indexed: 12/27/2022] Open
Abstract
A radioresistant cell line was established by fractionated ionizing radiation (IR) and assessed by a clonogenic assay, flow cytometry, and Western blot analysis, as well as zymography and a wound healing assay. Microarray was performed to profile global expression and to search for differentially expressed genes (DEGs) in response to IR. H460R cells demonstrated increased cell scattering and acidic vesicular organelles compared with parental cells. Concomitantly, H460R cells showed characteristics of increased migration and matrix metalloproteinase activity. In addition, H460R cells were resistant to IR, exhibiting reduced expression levels of ionizing responsive proteins (p-p53 and γ-H2AX); apoptosis-related molecules, such as cleaved poly(ADP ribose) polymerase; and endoplasmic reticulum stress-related molecules, such as glucose-regulated protein (GRP78) and C/EBP-homologous protein compared with parental cells, whereas the expression of anti-apoptotic X-linked inhibitor of apoptosis protein was increased. Among DEGs, syntrophin beta 2 (SNTB2) significantly increased in H460R cells in response to IR. Knockdown of SNTB2 by siRNA was more sensitive than the control after IR exposure in H460, H460R, and H1299 cells. Our study suggests that H460R cells have differential properties, including cell morphology, potential for metastasis, and resistance to IR, compared with parental cells. In addition, SNTB2 may play an important role in radioresistance. H460R cells could be helpful in in vitro systems for elucidating the molecular mechanisms of and discovering drugs to overcome radioresistance in lung cancer therapy.
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Affiliation(s)
- Chang-Nim Im
- Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul 139-706, Korea
| | - Byeong Mo Kim
- Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul 139-706, Korea
| | - Eun-Yi Moon
- Department of Bioscience and Biotechnology, Sejong University, Seoul 143-747, Korea
| | - Da-Won Hong
- Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul 139-706, Korea
| | - Joung Whan Park
- Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul 139-706, Korea
| | - Sung Hee Hong
- Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul 139-706, Korea
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Edeleva EV, Shcherbata HR. Stress-induced ECM alteration modulates cellular microRNAs that feedback to readjust the extracellular environment and cell behavior. Front Genet 2013; 4:305. [PMID: 24427166 PMCID: PMC3876577 DOI: 10.3389/fgene.2013.00305] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 12/16/2013] [Indexed: 12/14/2022] Open
Abstract
The extracellular environment is a complex entity comprising of the extracellular matrix (ECM) and regulatory molecules. It is highly dynamic and under cell-extrinsic stress, transmits the stressed organism’s state to each individual ECM-connected cell. microRNAs (miRNAs) are regulatory molecules involved in virtually all the processes in the cell, especially under stress. In this review, we analyse how miRNA expression is regulated downstream of various signal transduction pathways induced by changes in the extracellular environment. In particular, we focus on the muscular dystrophy-associated cell adhesion molecule dystroglycan capable of signal transduction. Then we show how exactly the same miRNAs feedback to regulate the extracellular environment. The ultimate goal of this bi-directional signal transduction process is to change cell behavior under cell-extrinsic stress in order to respond to it accordingly.
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Affiliation(s)
- Evgeniia V Edeleva
- Max Planck Research Group for Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry Göttingen, Germany
| | - Halyna R Shcherbata
- Max Planck Research Group for Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry Göttingen, Germany
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Aquilano K, Baldelli S, Ciriolo MR. Nuclear recruitment of neuronal nitric-oxide synthase by α-syntrophin is crucial for the induction of mitochondrial biogenesis. J Biol Chem 2013; 289:365-78. [PMID: 24235139 DOI: 10.1074/jbc.m113.506733] [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
Neuronal nitric-oxide synthase (nNOS) has various splicing variants and different subcellular localizations. nNOS can be found also in the nucleus; however, its exact role in this compartment is still not completely defined. In this report, we demonstrate that the PDZ domain allows the recruitment of nNOS to nuclei, thus favoring local NO production, nuclear protein S-nitrosylation, and induction of mitochondrial biogenesis. In particular, overexpression of PDZ-containing nNOS (nNOSα) increases S-nitrosylated CREB with consequent augmented binding on cAMP response element consensus sequence on peroxisome proliferator-activated receptor γ co-activator (PGC)-1α promoter. The resulting PGC-1α induction is accompanied by the expression of mitochondrial genes (e.g., TFAM, MtCO1) and increased mitochondrial mass. Importantly, full active nNOS lacking PDZ domain (nNOSβ) does not localize in nuclei and fails in inducing the expression of PGC-1α. Moreover, we substantiate that the mitochondrial biogenesis normally accompanying myogenesis is associated with nuclear translocation of nNOS. We demonstrate that α-Syntrophin, which resides in nuclei of myocytes, functions as the upstream mediator of nuclear nNOS translocation and nNOS-dependent mitochondrial biogenesis. Overall, our results indicate that altered nNOS splicing and nuclear localization could be contributing factors in human muscular diseases associated with mitochondrial impairment.
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Affiliation(s)
- Katia Aquilano
- From the Department of Biology, University of Rome "Tor Vergata," 00133 Rome, Italy and
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Neumeier M, Krautbauer S, Schmidhofer S, Hader Y, Eisinger K, Eggenhofer E, Froehner SC, Adams ME, Mages W, Buechler C. Adiponectin receptor 1 C-terminus interacts with PDZ-domain proteins such as syntrophins. Exp Mol Pathol 2013; 95:180-6. [PMID: 23860432 DOI: 10.1016/j.yexmp.2013.07.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 07/02/2013] [Indexed: 01/22/2023]
Abstract
Adiponectin receptor 1 (AdipoR1) is one of the two signaling receptors of adiponectin with multiple beneficial effects in metabolic diseases. AdipoR1 C-terminal peptide is concordant with the consensus sequence of class I PSD-95, disc large, ZO-1 (PDZ) proteins, and screening of a liver yeast two hybrid library identified binding to β2-syntrophin (SNTB2). Hybridization of a PDZ-domain array with AdipoR1 C-terminal peptide shows association with PDZ-domains of further proteins including β1- and α-syntrophin (SNTA). Interaction of PDZ proteins and C-terminal peptides requires a free carboxy terminus next to the PDZ-binding region and is blocked by carboxy terminal added tags. N-terminal tagged AdipoR1 is more highly expressed than C-terminal tagged receptor suggesting that the free carboxy terminus may form a complex with PDZ proteins to regulate cellular AdipoR1 levels. The C- and N-terminal tagged AdipoR1 proteins are mainly localized in the cytoplasma. N-terminal but not C-terminal tagged AdipoR1 colocalizes with syntrophins in adiponectin incubated Huh7 cells. Adiponectin induced hepatic phosphorylation of AMPK and p38 MAPK which are targets of AdipoR1 is, however, not blocked in SNTA and SNTB2 deficient mice. Further, AdipoR1 protein is similarly abundant in the liver of knock-out and wild type mice when kept on a standard chow or a high fat diet. In summary these data suggest that AdipoR1 protein levels are regulated by so far uncharacterized class I PDZ proteins which are distinct from SNTA and SNTB2.
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Affiliation(s)
- Markus Neumeier
- Department of Internal Medicine I, University of Regensburg, Regensburg, Germany
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39
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Gong B, Lee YS, Lee I, Shelite TR, Kunkeaw N, Xu G, Lee K, Jeon SH, Johnson BH, Chang Q, Ha T, Mendell NL, Cheng X, Bouyer DH, Boor PJ, Ksiazek TG, Walker DH. Compartmentalized, functional role of angiogenin during spotted fever group rickettsia-induced endothelial barrier dysfunction: evidence of possible mediation by host tRNA-derived small noncoding RNAs. BMC Infect Dis 2013; 13:285. [PMID: 23800282 PMCID: PMC3699377 DOI: 10.1186/1471-2334-13-285] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 06/12/2013] [Indexed: 01/19/2023] Open
Abstract
Background Microvascular endothelial barrier dysfunction is the central enigma in spotted fever group (SFG) rickettsioses. Angiogenin (ANG) is one of the earliest identified angiogenic factors, of which some are relevant to the phosphorylation of VE-cadherins that serve as endothelial adherens proteins. Although exogenous ANG is known to translocate into the nucleus of growing endothelial cells (ECs) where it plays a functional role, nuclear ANG is not detected in quiescent ECs. Besides its nuclear role, ANG is thought to play a cytoplasmic role, owing to its RNase activity that cleaves tRNA to produce small RNAs. Recently, such tRNA-derived RNA fragments (tRFs) have been shown to be induced under stress conditions. All these observations raise an intriguing hypothesis about a novel cytoplasmic role of ANG, which is induced upon infection with Rickettsia and generates tRFs that may play roles in SFG rickettsioses. Methods C3H/HeN mice were infected intravenously with a sublethal dose of R. conorii. At days 1, 3, and 5 post infection (p.i.), liver, lung and brain were collected for immunofluorescence (IF) studies of R. conorii and angiogenin (ANG). Human umbilical vein endothelial cells (HUVECs) were infected with R. conorii for 24, 48, and 72 hrs before incubation with 1μg/ml recombinant human ANG (rANG) in normal medium for 2 hrs. HUVEC samples were subjected to IF, exogenous ANG translocation, endothelial permeability, and immunoprecipitation phosphorylation assays. To identify small non-coding RNAs (sncRNAs) upon rickettsial infection, RNAs from pulverized mouse lung tissues and HUVECs were subjected to library preparation and deep sequencing analysis using an Illumina 2000 instrument. Identified sncRNAs were confirmed by Northern hybridization, and their target mRNAs were predicted in silico using BLAST and RNA hybrid programs. Results In the present study, we have demonstrated endothelial up-regulation of ANG, co-localized with SFG rickettsial infection in vivo. We also have provided direct evidence that rickettsial infection sensitizes human ECs to the translocation of exogenous ANG in a compartmentalized pattern at different times post-infection. Typically, exogenous ANG translocates into the nucleus at 24 hrs and to the cytoplasm at 72 hrs post-infection. The ANG cytoplasmic translocation enhances phosphorylation and destabilization of VE-cadherin and attenuates endothelial barrier function. Of note, deep sequencing analysis detected tRFs, mostly derived from the 5'-halves of host tRNAs, that are induced by ANG. Northern hybridization validates the two most abundantly cloned tRFs derived from tRNA-ValGTG and tRNA-GlyGCC, in both mouse tissues and human cells. Bioinformatics analysis predicted that these tRFs may interact with transcripts associated with the endothelial barrier, the host cell inflammatory response, and autophagy. Conclusions Our data provide new insight into the role of compartmentalized ANG during SFG rickettsioses, and highlight its possible mediation through tRFs.
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Affiliation(s)
- Bin Gong
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX, USA.
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