DOCSLIB.ORG

Human Adipocytes Induce Inflammation and Atrophy in Muscle Cells During Obesity

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Human Adipocytes Induce Inflammation and Atrophy in Muscle Cells During Obesity Diabetes Page 2 of 58 Human adipocytes induce inflammation and atrophy in muscle cells during obesity Pellegrinelli V1,2,3#, Rouault C1,2, 3, Rodriguez-Cuenca S4, Albert V1,2,3, Edom-Vovard F5,6,7,8 ,Vidal-Puig A4, Clément K 1, 2, 3*, Butler-Browne GS5,6,7,8* and Lacasa D1,2, 3* 1 - INSERM, U1166 Nutriomique, Paris, F-75006 France; 2 - Sorbonne Universités, University Pierre et Marie-Curie-Paris 6, UMR S 1166, Paris, F- 75006 France; 3- Institut Cardiométabolisme et Nutrition, ICAN, Pitié Salpétrière Hospital, Paris, F-75013 France; 4- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom; 5- Sorbonne Universités, University Pierre et Marie-Curie-Paris6, Centre de recherches en Myologie UMR 974, F-75005, Paris, France; 6- INSERM, U974, 75013, Paris, France; 7- CNRS FRE 3617, 75013, Paris, France; 8- Institut de Myologie, 75013, Paris, France. Key Words: muscle cells atrophy, visceral adipocytes, human obesity. Running title: obese human adipocytes induce muscle cells atrophy * These authors share senior co-authorship # Corresponding author: Current address: Wellcome Trust-MRC Institute of Metabolic Science, Metabolic Research Laboratories,University of Cambridge e-mail address: [email protected] Phone+44 (0)1223 336786 Fax: +44 1223 330598 Word count of body: 4568 Word count of abstract: 206 Number of figures/Tables: 7 Supplementary data 1 Diabetes Publish Ahead of Print, published online February 18, 2015 Page 3 of 58 Diabetes ABSTRACT Inflammation and lipid accumulation are hallmarks of muscular pathologies resulting from metabolic diseases such as obesity and type II diabetes. During obesity, the hypertrophy of visceral adipose tissue (VAT) contributes to muscle dysfunctions particularly through dysregulated production of adipokines. We have investigated the crosstalk between human adipocytes and skeletal muscle cells to identify mechanisms linking adiposity and muscular dysfunctions. First, we demonstrated that the secretome of obese adipocytes decreased the expression of contractile proteins in myotubes consequently inducing atrophy. Using a three-dimensional co- culture of human myotubes and VAT adipocytes we showed the decreased expression of genes corresponding to skeletal muscle contractility complex and myogenesis. We demonstrated an increased secretion by co-cultured cells of cytokines and chemokines with IL-6 and IL-1β as key contributors. Moreover, we gathered evidence showing that obese subcutaneous adipocytes were less potent than VAT adipocytes in inducing these myotubes dysfunctions. Interestingly, the atrophy induced by visceral adipocytes was corrected by IGF-II/IGFBP-5. Finally, we observed that skeletal muscle of obese mice displayed decreased expression of muscular markers in correlation with VAT hypertrophy and abnormal distribution of the muscle fiber size. In summary, we show the negative impact of obese adipocytes on the muscle phenotype that could contribute to muscle wasting associated with metabolic disorders. 2 Diabetes Page 4 of 58 INTRODUCTION During obesity, hypertrophy of white adipose tissue (WAT) is associated with fibro-inflammation and cell dysfunctions. However, visceral depot (VAT) differs from subcutaneous (SAT) by its inflammatory status due to its high infiltration with immune cells such as macrophages, T lymphocytes and mast cells (1,2). Hence, VAT hypertrophy is considered an important contributor to obesity related metabolic and cardiovascular diseases (3). In obese subjects, hypertrophied adipocytes display abnormal secretion of leptin and adiponectin, an increased production of numerous inflammatory cytokines and chemokines, leading to a disrupted inter- organ communication between VAT and important metabolic peripheral tissues such as liver and skeletal muscle (4). These organs are particularly exposed to free fatty acids and cytokines, mostly IL-6, increasingly released by visceral fat of obese subjects (5,6). Skeletal muscles are one of the major metabolic tissues of the body, playing a pivotal role in glucose and lipid metabolism. There is growing body of evidence showing the contribution of obesity on skeletal muscle dysfunctions, such as the development of insulin resistance, as attested by numerous studies performed in rodent models of obesity (7,8). Thus, it has been shown that obese rats display impaired activation of skeletal muscle protein synthesis in response to chronic lipid infiltration (9). Ectopic lipid storage in muscle (e.i. within muscle cells and/or in adipocytes located between muscle fibers) represents a negative risk factor for development of type 2 diabetes related to muscle insulin resistance (10–13). Moreover, skeletal muscle of obese subjects also displays an impairment in oxidative capacity (14) and abnormal muscle fiber organization (15,16). Increased amount of VAT in obesity has been proposed to link obesity and muscle metabolic alterations, such as insulin resistance. Surgical removal of VAT in rats leads to reduction of systemic concentrations of cytokines (e.g. IL-6, Fractalkine resistin) and improvement of skeletal muscle 3 Page 5 of 58 Diabetes insulin sensitivity (17). Particularly, adipocytes have been identified as potential effectors of muscle cells dysfunctions. Co-culture system previously showed impact of adipocytes on muscle cells insulin resistance and oxidative capacity (18–20). However, the impact of VAT adipocytes on muscle structural organization and the molecular factors involved remains elusive. Inflammatory mediators act synergistically to negatively impact regeneration capacity and insulin sensitivity in muscle (7). For example, IL-6 is overproduced by hypertrophied adipocytes and its systemic concentration is increased in obesity. Increased IL6 is associated with altered insulin signalling in myotubes and impaired myoblast differentiation/proliferation capacity leading to muscle atrophy (7,8). At the molecular level, IL-6 with IL-1β down-regulate IGFs/Akt signalling decreasing muscle protein synthesis (21). Excessive production of various mediators by obese VAT adipocytes could trigger a cross-talk with muscle cells, altering the production of myokines (22) which could affect in turn VAT endocrine functions. This cross-talk associated with an inflammatory microenvironment could be deleterious in perpetuating a vicious cycle leading to muscle loss and wasting. To address this question, the secretome of obese adipocytes was tested on human primary muscle cells and direct co-cultures were performed. The main aim of our study was to identify the major contributors of VAT adipocytes/skeletal muscle crosstalk and their role in inducing muscle atrophy and inflammation, common disorders associated with metabolic pathologies such as obesity and type 2 diabetes (4). Research Design and Methods The antibodies and recombinant proteins used in the study are listed in Table S1. Mice studies 4 Diabetes Page 6 of 58 C57BL/6N male mice were purchased from Charles River. Standard chow or 58 kcal% fat w/sucrose Surwit Diet (HFD, D12331, Research Diets) was given ad libitum to animals. Dietary intervention started at 8 weeks of age and continued for 12 or 16 weeks (n=8-9 per experimental group). The detailed procedures of the mice studies are provided in (23). Adipose tissues and skeletal muscles from 12 weeks chow/HFD mice (RNA extraction) and Gastrocnemius muscle of 16 weeks chow/HFD mice (histological analysis) were prepared as described in (23,24). Muscle fiber cross-section size (up to 201 muscle fibers/section) was automatically evaluated by determination of the Feret’s diameter (Image J software) in 3 independent fields in each section. The variance coefficient of the Feret’s diameter was defined to evaluate the muscle fiber size variability between the experimental groups of mice and avoid experimental errors such as the orientation of the sectioning angle (25). Number of intermuscular adipocyte spots was assessed visually in the total longitudinal section biopsy. Human studies Subcutaneous (SAT) and VAT biopsies were obtained from morbid obese subjects (body mass index, BMI>40 kg/m2) (clinical parameters in Table S2) and SAT biopsies from lean female subjects (BMI<25 kg/m2) undergoing elective surgery. None of the lean subjects had diabetes or metabolic disorders, and none were taking medication. All clinical investigations were performed according to the Declaration of Helsinki and approved by the Ethical Committee of Hôtel-Dieu Hospital (Paris, France). Isolation of mature adipocytes from human WAT and preparation of the 3D adipocyte cultures 5 Page 7 of 58 Diabetes Tridimensional gels were prepared with mature adipocytes isolated from WAT of lean (SAT) or obese (SAT and VAT) subjects as described in (26,27). Adipocytes were embedded in the hydrogel (Puramatrix, BD Biosciences, Bedford, MA, USA). Hydrogel was diluted in 20% sucrose solution at a concentration of 1x 105cells per 1mL of gel preparation into 24-well plates containing 1.5ml of DMEM/F12 (1% bovine albumin, 1% antibiotics). Culture medium was changed after 1h with fresh medium containing human insulin (50 nM). Adipocytes from SAT or VAT were incubated for 48h before collecting the conditioned media referred as lean SAT CM (lean SAT adipocyte conditioned media) and obese SAT/VAT CM (obese SAT/VAT adipocyte conditioned media), respectively. Samples were kept at -80°C prior experimental measurements. Myoblast cultures, differentiation to myotubes and treatment with adipocyte conditioned
Load more

Recommended publications
  • Treatment of Aged Mice and Long-Term Durability of AAV-Mediated Gene Therapy in Two Mouse Models of LGMD Eric R
    P.137 Treatment of Aged Mice and Long-term Durability of AAV-Mediated Gene Therapy in Two Mouse Models of LGMD Eric R. Pozsgai, Danielle A. Griffin, Ellyn L. Peterson, Amber Kempton, Oliver Rogers, Young-Eun Seo, Louise R. Rodino-Klapac Sarepta Therapeutics, Inc., Cambridge, Massachusetts, USA BACKGROUND RESULTS RESULTS (CONT’D) • The sarcoglycanopathies are a subset of autosomal recessive limb-girdle muscular dystrophies (LGMD) Figure 1. Expression analysis: Immunofluorescence staining and western blot on skeletal • Functional improvement was observed with significantly increased resistance to contraction-induced injury resulting from mutations in the sarcoglycans (α, β, γ, and δ-SG) leading to protein deficiency, loss of in the TA muscle (Figure 3). formation of the sarcoglycan complex, and loss of stabilization of the dystrophin-associated protein muscle indicating biomarker expression in aged, severely diseased muscle complex (DAPC). Figure 3. Functional analysis: Protection of force output following long-term treatment of • Sarcoglycanopathies present as progressive muscular dystrophies starting in the girdle muscles before aged SGCA-/- mice with severely diseased muscle extending to lower and upper extremity muscles, and can also present in the diaphragm and heart, resulting in respiratory and cardiac failure in specific patient subtypes. SKELETAL MUSCLE • Adeno-associated virus (AAV)-mediated gene transfer therapy has shown early signs of potential to treat sarcoglycanopathies. Key considerations include a systematic and stepwise
    [Show full text]
  • Supplementary Table 3 Complete List of RNA-Sequencing Analysis of Gene Expression Changed by ≥ Tenfold Between Xenograft and Cells Cultured in 10%O2
    Supplementary Table 3 Complete list of RNA-Sequencing analysis of gene expression changed by ≥ tenfold between xenograft and cells cultured in 10%O2 Expr Log2 Ratio Symbol Entrez Gene Name (culture/xenograft) -7.182 PGM5 phosphoglucomutase 5 -6.883 GPBAR1 G protein-coupled bile acid receptor 1 -6.683 CPVL carboxypeptidase, vitellogenic like -6.398 MTMR9LP myotubularin related protein 9-like, pseudogene -6.131 SCN7A sodium voltage-gated channel alpha subunit 7 -6.115 POPDC2 popeye domain containing 2 -6.014 LGI1 leucine rich glioma inactivated 1 -5.86 SCN1A sodium voltage-gated channel alpha subunit 1 -5.713 C6 complement C6 -5.365 ANGPTL1 angiopoietin like 1 -5.327 TNN tenascin N -5.228 DHRS2 dehydrogenase/reductase 2 leucine rich repeat and fibronectin type III domain -5.115 LRFN2 containing 2 -5.076 FOXO6 forkhead box O6 -5.035 ETNPPL ethanolamine-phosphate phospho-lyase -4.993 MYO15A myosin XVA -4.972 IGF1 insulin like growth factor 1 -4.956 DLG2 discs large MAGUK scaffold protein 2 -4.86 SCML4 sex comb on midleg like 4 (Drosophila) Src homology 2 domain containing transforming -4.816 SHD protein D -4.764 PLP1 proteolipid protein 1 -4.764 TSPAN32 tetraspanin 32 -4.713 N4BP3 NEDD4 binding protein 3 -4.705 MYOC myocilin -4.646 CLEC3B C-type lectin domain family 3 member B -4.646 C7 complement C7 -4.62 TGM2 transglutaminase 2 -4.562 COL9A1 collagen type IX alpha 1 chain -4.55 SOSTDC1 sclerostin domain containing 1 -4.55 OGN osteoglycin -4.505 DAPL1 death associated protein like 1 -4.491 C10orf105 chromosome 10 open reading frame 105 -4.491
    [Show full text]
  • 32-3099: PRKAB1 Recombinant Protein Description
    9853 Pacific Heights Blvd. Suite D. San Diego, CA 92121, USA Tel: 858-263-4982 Email: [email protected] 32-3099: PRKAB1 Recombinant Protein Alternative Name : AMPK,HAMPKb,5'-AMP-activated protein kinase subunit beta-1,AMPK subunit beta-1,AMPKb,PRKAB1. Description Source : E.coli. PRKAB1 Human Recombinant produced in E.Coli is a single, non-glycosylated, polypeptide chain containing 293 amino acids (1-270 a.a.) and having a molecular mass of 32.8 kDa. The PRKAB1 is fused to a 23 amino acid His Tag at N- Terminus and purified by proprietary chromatographic techniques. 5'-AMP-activated protein kinase subunit beta-1 (PRKAB1) hinders protein, carbohydrate and lipid biosynthesis, in addition to cell growth and proliferation. AMPK is a heterotrimer comprised of an alpha catalytic subunit, and non-catalytic beta and gamma subunits. AMPK acts via direct phosphorylation of metabolic enzymes, and longer-term effects by phosphorylation of transcription regulators. PRKAB1 is a regulator of cellular polarity by remodeling the actin cytoskeleton; most likely by indirectly activating myosin. Beta non-catalytic subunit acts as a scaffold on which the AMPK complex compiles, through its C-terminus that joins alpha (PRKAA1 or PRKAA2) and gamma subunits (PRKAG1, PRKAG2 or PRKAG3). Product Info Amount : 5 µg Purification : Greater than 85% as determined by SDS-PAGE. The PRKAB1 protein solution (0.5mg/ml) contains 20mM Tris-HCl buffer (pH 8.0), 0.15M NaCl, Content : 10% glycerol and 1mM DTT. Store at 4°C if entire vial will be used within 2-4 weeks. Store, frozen at -20°C for longer periods of Storage condition : time.
    [Show full text]
  • Human Kinome Profiling Identifies a Requirement for AMP-Activated
    Human kinome profiling identifies a requirement for AMP-activated protein kinase during human cytomegalovirus infection Laura J. Terrya, Livia Vastagb,1, Joshua D. Rabinowitzb, and Thomas Shenka,2 aDepartment of Molecular Biology and bDepartment of Chemistry and the Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544 Contributed by Thomas Shenk, January 11, 2012 (sent for review December 29, 2011) Human cytomegalovirus (HCMV) modulates numerous cellular (7). Thus, the connections between AMPK activity and metabolic signaling pathways. Alterations in signaling are evident from the changes during HCMV infection have remained unclear. broad changes in cellular phosphorylation that occur during HCMV We confirmed the requirement for AMPK during infection, infection and from the altered activity of multiple kinases. Here we and we show that an AMPK antagonist, compound C, blocks report a comprehensive RNAi screen, which predicts that 106 cellular HCMV-induced changes to glycolysis and inhibits viral gene kinases influence growth of the virus, most of which were not expression. These studies argue that AMPK or a related, com- previously linked to HCMV replication. Multiple elements of the pound C-sensitive kinase is an essential contributor to metabolic AMP-activated protein kinase (AMPK) pathway scored in the screen. changes initiated by HCMV and provide unique insight into As a regulator of carbon and nucleotide metabolism, AMPK is poised potential antiviral strategies. to activate many of the metabolic pathways induced by HCMV infection. An AMPK inhibitor, compound C, blocked a substantial Results portion of HCMV-induced metabolic changes, inhibited the accumu- HumanKinomeScreenIdentifies Putative Effectors of HCMV Replication. lation of all HCMV proteins tested, and markedly reduced the We conducted an siRNA screen of the human kinome to perform an production of infectious progeny.
    [Show full text]
  • Profiling Data
    Compound Name DiscoveRx Gene Symbol Entrez Gene Percent Compound Symbol Control Concentration (nM) JNK-IN-8 AAK1 AAK1 69 1000 JNK-IN-8 ABL1(E255K)-phosphorylated ABL1 100 1000 JNK-IN-8 ABL1(F317I)-nonphosphorylated ABL1 87 1000 JNK-IN-8 ABL1(F317I)-phosphorylated ABL1 100 1000 JNK-IN-8 ABL1(F317L)-nonphosphorylated ABL1 65 1000 JNK-IN-8 ABL1(F317L)-phosphorylated ABL1 61 1000 JNK-IN-8 ABL1(H396P)-nonphosphorylated ABL1 42 1000 JNK-IN-8 ABL1(H396P)-phosphorylated ABL1 60 1000 JNK-IN-8 ABL1(M351T)-phosphorylated ABL1 81 1000 JNK-IN-8 ABL1(Q252H)-nonphosphorylated ABL1 100 1000 JNK-IN-8 ABL1(Q252H)-phosphorylated ABL1 56 1000 JNK-IN-8 ABL1(T315I)-nonphosphorylated ABL1 100 1000 JNK-IN-8 ABL1(T315I)-phosphorylated ABL1 92 1000 JNK-IN-8 ABL1(Y253F)-phosphorylated ABL1 71 1000 JNK-IN-8 ABL1-nonphosphorylated ABL1 97 1000 JNK-IN-8 ABL1-phosphorylated ABL1 100 1000 JNK-IN-8 ABL2 ABL2 97 1000 JNK-IN-8 ACVR1 ACVR1 100 1000 JNK-IN-8 ACVR1B ACVR1B 88 1000 JNK-IN-8 ACVR2A ACVR2A 100 1000 JNK-IN-8 ACVR2B ACVR2B 100 1000 JNK-IN-8 ACVRL1 ACVRL1 96 1000 JNK-IN-8 ADCK3 CABC1 100 1000 JNK-IN-8 ADCK4 ADCK4 93 1000 JNK-IN-8 AKT1 AKT1 100 1000 JNK-IN-8 AKT2 AKT2 100 1000 JNK-IN-8 AKT3 AKT3 100 1000 JNK-IN-8 ALK ALK 85 1000 JNK-IN-8 AMPK-alpha1 PRKAA1 100 1000 JNK-IN-8 AMPK-alpha2 PRKAA2 84 1000 JNK-IN-8 ANKK1 ANKK1 75 1000 JNK-IN-8 ARK5 NUAK1 100 1000 JNK-IN-8 ASK1 MAP3K5 100 1000 JNK-IN-8 ASK2 MAP3K6 93 1000 JNK-IN-8 AURKA AURKA 100 1000 JNK-IN-8 AURKA AURKA 84 1000 JNK-IN-8 AURKB AURKB 83 1000 JNK-IN-8 AURKB AURKB 96 1000 JNK-IN-8 AURKC AURKC 95 1000 JNK-IN-8
    [Show full text]
  • Gene Expression Profiling of Micrornas Associated with UCA1 in Bladder Cancer Cells
    INTERNATIONAL JOURNAL OF ONCOLOGY 48: 1617-1627, 2016 Gene expression profiling of microRNAs associated with UCA1 in bladder cancer cells XIAOJUAN XIE1,2, JINGJING PAN1, LIQIANG WEI2, SHOUZHEN WU3, HUILIAN HOU4, XU LI3 and WEI CHEN1 1Department of Clinical Laboratory, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061; 2Shaanxi Center for Clinical Laboratory, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068; 3Center for Translational Medicine, 4Department of Pathology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China Received November 11, 2015; Accepted December 27, 2015 DOI: 10.3892/ijo.2016.3357 Abstract. Emerging evidence indicates that non-coding and positively correlated with miR-196a, whereas UCA1 and RNAs, such as lncRNAs and microRNAs, play important miR-196a were negatively correlated with p27kip1, which was roles in diverse diseases, such as cancer, immune diseases downregulated in bladder cancer patients. Thus, our findings and cardiovascular diseases. Interestingly, lncRNAs could provided valuable information on miRNAs associated with directly or indirectly regulate the expression of miRNAs. UCA1 in bladder cancer, which could be helpful to further However, the expression profiling of miRNAs associated with explore the related genes and molecular networks fundamental UCA1 in bladder cancer remains unknown. Here, we used in bladder cancer progression. Illumina deep sequencing to sequence miRNA libraries from both the UCA1 knockdown and normal high-expression 5637 Introduction cells. We identified 225 and 235 miRNAs expressed in 5637 cells of normal high-expression and knockdown of UCA1, Recently, emerging studies have demonstrated that 70-90% of respectively.
    [Show full text]
  • New Insights in RBM20 Cardiomyopathy
    Current Heart Failure Reports (2020) 17:234–246 https://doi.org/10.1007/s11897-020-00475-x TRANSLATIONAL RESEARCH IN HEART FAILURE (J BACKS & M VAN DEN HOOGENHOF, SECTION EDITORS) New Insights in RBM20 Cardiomyopathy D. Lennermann1,2 & J. Backs1,2 & M. M. G. van den Hoogenhof1,2 Published online: 13 August 2020 # The Author(s) 2020 Abstract Purpose of Review This review aims to give an update on recent findings related to the cardiac splicing factor RNA-binding motif protein 20 (RBM20) and RBM20 cardiomyopathy, a form of dilated cardiomyopathy caused by mutations in RBM20. Recent Findings While most research on RBM20 splicing targets has focused on titin (TTN), multiple studies over the last years have shown that other splicing targets of RBM20 including Ca2+/calmodulin-dependent kinase IIδ (CAMK2D) might be critically involved in the development of RBM20 cardiomyopathy. In this regard, loss of RBM20 causes an abnormal intracellular calcium handling, which may relate to the arrhythmogenic presentation of RBM20 cardiomyopathy. In addition, RBM20 presents clinically in a highly gender-specific manner, with male patients suffering from an earlier disease onset and a more severe disease progression. Summary Further research on RBM20, and treatment of RBM20 cardiomyopathy, will need to consider both the multitude and relative contribution of the different splicing targets and related pathways, as well as gender differences. Keywords RBM20 . Dilated cardiomyopathy . CaMKIIδ . Calcium handling . Gender differences . Titin Introduction (ARVC), where a small number of genes account for most of the genetic causes, DCM-causing mutations have been ob- Dilated cardiomyopathy (DCM), as defined by left ventricular served in a variety of genes of diverse ontology [2].
    [Show full text]
  • A Missense Mutation in the RSRSP Stretch of Rbm20 Causes Dilated
    www.nature.com/scientificreports OPEN A missense mutation in the RSRSP stretch of Rbm20 causes dilated cardiomyopathy and atrial fbrillation in mice Kensuke Ihara1,2*, Tetsuo Sasano2, Yuichi Hiraoka3, Marina Togo‑Ohno4, Yurie Soejima5, Motoji Sawabe5, Megumi Tsuchiya6, Hidesato Ogawa6, Tetsushi Furukawa1 & Hidehito Kuroyanagi4* Dilated cardiomyopathy (DCM) is a fatal heart disease characterized by left ventricular dilatation and cardiac dysfunction. Recent genetic studies on DCM have identifed causative mutations in over 60 genes, including RBM20, which encodes a regulator of heart‑specifc splicing. DCM patients with RBM20 mutations have been reported to present with more severe cardiac phenotypes, including impaired cardiac function, atrial fbrillation (AF), and ventricular arrhythmias leading to sudden cardiac death, compared to those with mutations in the other genes. An RSRSP stretch of RBM20, a hotspot of missense mutations found in patients with idiopathic DCM, functions as a crucial part of its nuclear localization signals. However, the relationship between mutations in the RSRSP stretch and cardiac phenotypes has never been assessed in an animal model. Here, we show that Rbm20 mutant mice harboring a missense mutation S637A in the RSRSP stretch, mimicking that in a DCM patient, demonstrated severe cardiac dysfunction and spontaneous AF and ventricular arrhythmias mimicking the clinical state in patients. In contrast, Rbm20 mutant mice with frame‑shifting deletion demonstrated less severe phenotypes, although loss of RBM20‑dependent alternative splicing was indistinguishable. RBM20S637A protein cannot be localized to the nuclear speckles, but accumulated in cytoplasmic, perinuclear granule‑like structures in cardiomyocytes, which might contribute to the more severe cardiac phenotypes. Dilated cardiomyopathy (DCM) is a fatal cardiac disease characterized by enlargement of the cardiac chambers and impaired systolic function1.
    [Show full text]
  • Limb-Girdle Muscular Dystrophy
    www.ChildLab.com 800-934-6575 LIMB-GIRDLE MUSCULAR DYSTROPHY What is Limb-Girdle Muscular Dystrophy? Limb-Girdle Muscular Dystrophy (LGMD) is a group of hereditary disorders that cause progressive muscle weakness and wasting of the shoulders and pelvis (hips). There are at least 13 different genes that cause LGMD, each associated with a different subtype. Depending on the subtype of LGMD, the age of onset is variable (childhood, adolescence, or early adulthood) and can affect other muscles of the body. Many persons with LGMD eventually need the assistance of a wheelchair, and currently there is no cure. How is LGMD inherited? LGMD can be inherited by autosomal dominant (AD) or autosomal recessive (AR) modes. The AR subtypes are much more common than the AD types. Of the AR subtypes, LGMD2A (calpain-3) is the most common (30% of cases). LGMD2B (dysferlin) accounts for 20% of cases and the sarcoglycans (LGMD2C-2F) as a group comprise 25%-30% of cases. The various subtypes represent the different protein deficiencies that can cause LGMD. What testing is available for LGMD? Diagnosis of the LGMD subtypes requires biochemical and genetic testing. This information is critical, given that management of the disease is tailored to each individual and each specific subtype. Establishing the specific LGMD subtype is also important for determining inheritance and recurrence risks for the family. The first step in diagnosis for muscular dystrophy is usually a muscle biopsy. Microscopic and protein analysis of the biopsy can often predict the type of muscular dystrophy by analyzing which protein(s) is absent. A muscle biopsy will allow for targeted analysis of the appropriate LGMD gene(s) and can rule out the diagnosis of the more common dystrophinopathies (Duchenne and Becker muscular dystrophies).
    [Show full text]
  • Sudden Cardiac Death: Use of Genetics in the Diagnosis
    Sudden Cardiac Death: Use of Genetics in the diagnosis Ramon Brugada MD PhD [email protected] “Genetic testing is expensive; the system can not afford it” However, the real question is can we, physicians, afford not doing it? CORONARY ARTERY DISEASE CAUSES 80% OF SUDDEN CARDIAC DEATHS What do young people die from? From the patient to the research laboratory BRUGADA SYNDROME SHORT QT SCN5A SYNDROME KCNH2 HYPERTROPHIC LONG QT CARDIOMYOPATHY SYNDROME MYOSIN HEAVY CHAIN KCNQ1 DILATED CARDIOMYOPATHY MARFAN SYNDROME LAMIN A/C FIBRILLIN-1 Genetics of Sudden Cardiac Death Hypertrophic Cardiomyopathy Assymetric hypertrophy of the left ventricle. Most common cause of sudden cardiac death in the athlete. Steve R. Ommen, and Bernard J. Gersh Eur Heart J 2009 Dilated Cardiomyopathy Gene Symbol Gene Symbol Cardiac α-actin ACTC Telethonin (T-cap) TCAP β-Myosin heavy chain MYH α-Sarcoglycan SGCA Cardiac troponin T TNNT2 β-Sarcoglycan SGCB α-Tropomyosin TPM1 δ-Sarcoglycan SGCD Titin TTN Dystrophin DMD Arrhythmogenic Right Ventricular Dysplasia Right ventricular dilatation Fibro adipose myocardial substitution Sudden death often the first symptom Sudden Cardiac Death: Electrical Short QT syndrome Brugada syndrome CPVT Long QT syndrome Long QT syndrome: Diagnosis Short QT syndrome: Diagnosis Gollob MH et al. J Am Coll Cardiol 2011 Catecholaminergic polymorphic ventricular tachycardia Brugada Syndrome Diagnosis Genetic diseases associated with sudden cardiac death CARDIOMYOPATHIES CHANNELOPATHIES Sudden Death: Monogenic diseases Diseases associated with
    [Show full text]
  • Troponin Variants in Congenital Myopathies: How They Affect Skeletal Muscle Mechanics
    International Journal of Molecular Sciences Review Troponin Variants in Congenital Myopathies: How They Affect Skeletal Muscle Mechanics Martijn van de Locht , Tamara C. Borsboom, Josine M. Winter and Coen A. C. Ottenheijm * Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, Location VUmc, 1081 HZ Amsterdam, The Netherlands; [email protected] (M.v.d.L.); [email protected] (T.C.B.); [email protected] (J.M.W.) * Correspondence: [email protected]; Tel.: +31-(0)-20-444-8123 Abstract: The troponin complex is a key regulator of muscle contraction. Multiple variants in skeletal troponin encoding genes result in congenital myopathies. TNNC2 has been implicated in a novel congenital myopathy, TNNI2 and TNNT3 in distal arthrogryposis (DA), and TNNT1 and TNNT3 in nemaline myopathy (NEM). Variants in skeletal troponin encoding genes compromise sarcomere function, e.g., by altering the Ca2+ sensitivity of force or by inducing atrophy. Several potential therapeutic strategies are available to counter the effects of variants, such as troponin activators, introduction of wild-type protein through AAV gene therapy, and myosin modulation to improve muscle contraction. The mechanisms underlying the pathophysiological effects of the variants in skeletal troponin encoding genes are incompletely understood. Furthermore, limited knowledge is available on the structure of skeletal troponin. This review focusses on the physiology of slow and fast skeletal troponin and the pathophysiology of reported variants in skeletal troponin encoding genes. A better understanding of the pathophysiological effects of these variants, together with enhanced knowledge regarding the structure of slow and fast skeletal troponin, will direct the development of Citation: van de Locht, M.; treatment strategies.
    [Show full text]
  • Supplementary Table 9. Functional Annotation Clustering Results for the Union (GS3) of the Top Genes from the SNP-Level and Gene-Based Analyses (See ST4)
    Supplementary Table 9. Functional Annotation Clustering Results for the union (GS3) of the top genes from the SNP-level and Gene-based analyses (see ST4) Column Header Key Annotation Cluster Name of cluster, sorted by descending Enrichment score Enrichment Score EASE enrichment score for functional annotation cluster Category Pathway Database Term Pathway name/Identifier Count Number of genes in the submitted list in the specified term % Percentage of identified genes in the submitted list associated with the specified term PValue Significance level associated with the EASE enrichment score for the term Genes List of genes present in the term List Total Number of genes from the submitted list present in the category Pop Hits Number of genes involved in the specified term (category-specific) Pop Total Number of genes in the human genome background (category-specific) Fold Enrichment Ratio of the proportion of count to list total and population hits to population total Bonferroni Bonferroni adjustment of p-value Benjamini Benjamini adjustment of p-value FDR False Discovery Rate of p-value (percent form) Annotation Cluster 1 Enrichment Score: 3.8978262119731335 Category Term Count % PValue Genes List Total Pop Hits Pop Total Fold Enrichment Bonferroni Benjamini FDR GOTERM_CC_DIRECT GO:0005886~plasma membrane 383 24.33290978 5.74E-05 SLC9A9, XRCC5, HRAS, CHMP3, ATP1B2, EFNA1, OSMR, SLC9A3, EFNA3, UTRN, SYT6, ZNRF2, APP, AT1425 4121 18224 1.18857065 0.038655922 0.038655922 0.086284383 UP_KEYWORDS Membrane 626 39.77128335 1.53E-04 SLC9A9, HRAS,
    [Show full text]