51
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Watson LPE, Carr KS, Venables MC, Acerini CL, Lyons G, Moran C, Murgatroyd PR, Chatterjee K. Quantifying energy expenditure in childhood: utility in managing pediatric metabolic disorders. Am J Clin Nutr 2019; 110:1186-1191. [PMID: 31410443 PMCID: PMC6821543 DOI: 10.1093/ajcn/nqz177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 07/10/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Energy expenditure prediction equations are used to estimate energy intake based on general population measures. However, when using equations to compare with a disease cohort with known metabolic abnormalities, it is important to derive one's own equations based on measurement conditions matching the disease cohort. OBJECTIVE We aimed to use newly developed prediction equations based on a healthy pediatric population to describe and predict resting energy expenditure (REE) in a cohort of pediatric patients with thyroid disorders. METHODS Body composition was measured by DXA and REE was assessed by indirect calorimetry in 201 healthy participants. A prediction equation for REE was derived in 100 healthy participants using multiple linear regression and z scores were calculated. The equation was validated in 101 healthy participants. This method was applied to participants with resistance to thyroid hormone (RTH) disorders, due to mutations in either thyroid hormone receptor β or α (β: female n = 17, male n = 9; α: female n = 1, male n = 1), with deviation of REE in patients compared with the healthy population presented by the difference in z scores. RESULTS The prediction equation for REE = 0.061 * Lean soft tissue (kg) - 0.138 * Sex (0 male, 1 female) + 2.41 (R2 = 0.816). The mean ± SD of the residuals is -0.02 ± 0.44 kJ/min. Mean ± SD REE z scores for RTHβ patients are -0.02 ± 1.26. z Scores of -1.69 and -2.05 were recorded in male (n = 1) and female ( n = 1) RTHα patients. CONCLUSIONS We have described methodology whereby differences in REE between patients with a metabolic disorder and healthy participants can be expressed as a z score. This approach also enables change in REE after a clinical intervention (e.g., thyroxine treatment of RTHα) to be monitored.
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Affiliation(s)
- Laura P E Watson
- National Institute for Health Research (NIHR) Cambridge Clinical Research Facility, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Katherine S Carr
- National Institute for Health Research (NIHR) Cambridge Clinical Research Facility, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Michelle C Venables
- Nutrition Surveys and Studies, Medical Research Council (MRC) Elsie Widdowson Laboratory, Cambridge, United Kingdom
- NIHR Biomedical Research Centre Nutritional Biomarker Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Carlo L Acerini
- Department of Pediatrics, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Greta Lyons
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Carla Moran
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Peter R Murgatroyd
- National Institute for Health Research (NIHR) Cambridge Clinical Research Facility, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Krishna Chatterjee
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, United Kingdom
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52
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Akinci B, Oral EA, Neidert A, Rus D, Cheng WY, Thompson-Leduc P, Cheung HC, Bradt P, Foss de Freitas MC, Montenegro RM, Fernandes VO, Cochran E, Brown RJ. Comorbidities and Survival in Patients With Lipodystrophy: An International Chart Review Study. J Clin Endocrinol Metab 2019; 104:5120-5135. [PMID: 31314093 PMCID: PMC6760298 DOI: 10.1210/jc.2018-02730] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 07/11/2019] [Indexed: 12/13/2022]
Abstract
CONTEXT Limited natural history data are available in patients with non-HIV-related lipodystrophy syndromes who never received disease-specific therapies, making interpretation of benefits of therapies in lipodystrophy syndromes challenging. OBJECTIVE We assessed the natural history of non-HIV-related generalized lipodystrophy (GL) and partial lipodystrophy (PL) in patients who have never received leptin or other lipodystrophy-specific therapies. DESIGN/SETTING/PATIENTS We conducted an international chart review of 230 patients with confirmed GL or PL at five treatment centers who never received leptin or other lipodystrophy-specific therapies. Patients were observed from birth to loss to follow-up, death, or date of chart abstraction. OUTCOME MEASURES Lifetime prevalence of diabetes/insulin resistance and select organ abnormalities, time to diabetes/insulin resistance, first organ abnormality, disease progression, and mortality were described. RESULTS Diabetes/insulin resistance was identified in 58.3% of patients. Liver abnormalities were the most common organ abnormality (71.7%), followed by kidney (40.4%), heart (30.4%), and pancreatitis (13.0%). Kaplan-Meier estimates of mean (SE) time to first organ abnormality were 7.7 years (0.9) in GL and 16.1 years (1.5) in PL (P < 0.001). Mean time to diabetes/insulin resistance was 12.7 years (1.2) in GL and 19.1 years (1.7) in PL (P = 0.131). Mean time to disease progression was 7.6 years (0.8) and comparable between GL and PL subgroups (P = 0.393). Mean time to death was 51.2 years (3.5) in GL and 66.6 years (1.0) in PL (P < 0.001). CONCLUSIONS This large-scale study provides comprehensive, long-term data across multiple countries on the natural history of non-HIV-related lipodystrophy.
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Affiliation(s)
| | - Elif A Oral
- Division of Metabolism, Endocrine & Diabetes and Brehm Center for Diabetes Research, Department of Internal Medicine, Michigan Medicine, University of Michigan, Ann Arbor, Michigan
| | - Adam Neidert
- Division of Metabolism, Endocrine & Diabetes and Brehm Center for Diabetes Research, Department of Internal Medicine, Michigan Medicine, University of Michigan, Ann Arbor, Michigan
| | - Diana Rus
- Division of Metabolism, Endocrine & Diabetes and Brehm Center for Diabetes Research, Department of Internal Medicine, Michigan Medicine, University of Michigan, Ann Arbor, Michigan
| | | | | | | | - Pamela Bradt
- Aegerion Pharmaceuticals Inc., Cambridge, Massachusetts
| | | | | | | | - Elaine Cochran
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Rebecca J Brown
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
- Correspondence and Reprint Requests: Rebecca J. Brown, MD, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 10 Center Drive, Bethesda, Maryland 20814. E-mail:
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53
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Chen VL, Wright AP, Halligan B, Chen Y, Du X, Handelman SK, Long MT, Kiel DP, Speliotes EK. Body Composition and Genetic Lipodystrophy Risk Score Associate With Nonalcoholic Fatty Liver Disease and Liver Fibrosis. Hepatol Commun 2019; 3:1073-1084. [PMID: 31388628 PMCID: PMC6671828 DOI: 10.1002/hep4.1391] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 05/21/2019] [Indexed: 12/20/2022] Open
Abstract
Up to 25% of patients with nonalcoholic fatty liver disease (NAFLD) are not obese but may have a fat or muscle composition that predisposes them to NAFLD. Our aim was to determine whether body composition parameters associate with NAFLD and to identify genetic contributors to this association. This study included two cohorts. The first included 2,249 participants from the Framingham Heart Study who underwent a computed tomography scan to evaluate hepatic steatosis, dual-energy x-ray absorptiometry testing to assess body composition, and clinical examination. Body composition parameters were normalized to total body weight. A subset of participants underwent genotyping with an Affymetrix 550K single-nucleotide polymorphism array. The second cohort, Michigan Genomics Initiative, included 19,239 individuals with genotyping on the Illumina HumanCoreExome v.12.1 array and full electronic health record data. Using sex-stratified multivariable linear regression, greater central body fat associated with increased hepatic steatosis while greater lower extremity body fat associated with decreased hepatic steatosis. Greater appendicular lean mass was associated with decreased hepatic steatosis in men but not in women. A polygenic risk score for lipodystrophy (regional or global loss of adipose tissue) was associated with increased hepatic steatosis, increased liver fibrosis, and decreased lower extremity fat mass. Conclusion: Greater central body fat associated with increased hepatic steatosis, while greater lower extremity body fat and, in men, greater appendicular lean mass were associated with decreased hepatic steatosis. A genetic risk score for lipodystrophy was associated with NAFLD and liver fibrosis. Our results suggest that buffering of excess energy by peripheral fat and muscle may protect against NAFLD and liver fibrosis in the general population.
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Affiliation(s)
- Vincent L. Chen
- Division of Gastroenterology and Hepatology, Department of MedicineUniversity of Michigan Health SystemAnn ArborMI
- Department of Computational Medicine and BioinformaticsUniversity of Michigan Medical SchoolAnn ArborMI
| | - Andrew P. Wright
- Division of Gastroenterology and Hepatology, Department of MedicineUniversity of Michigan Health SystemAnn ArborMI
- Division of GastroenterologyLoma Linda University HealthLoma LindaCA
| | - Brian Halligan
- Division of Gastroenterology and Hepatology, Department of MedicineUniversity of Michigan Health SystemAnn ArborMI
| | - Yanhua Chen
- Division of Gastroenterology and Hepatology, Department of MedicineUniversity of Michigan Health SystemAnn ArborMI
| | - Xiaomeng Du
- Division of Gastroenterology and Hepatology, Department of MedicineUniversity of Michigan Health SystemAnn ArborMI
| | - Samuel K. Handelman
- Division of Gastroenterology and Hepatology, Department of MedicineUniversity of Michigan Health SystemAnn ArborMI
- Department of Computational Medicine and BioinformaticsUniversity of Michigan Medical SchoolAnn ArborMI
| | - Michelle T. Long
- Section of GastroenterologyBoston Medical Center, Boston University School of MedicineBostonMA
| | - Douglas P. Kiel
- Hebrew SeniorLifeInstitute for Aging Research, Department of MedicineBeth Israel Deaconess Medical CenterBostonMA
- Harvard Medical SchoolBostonMA
| | - Elizabeth K. Speliotes
- Division of Gastroenterology and Hepatology, Department of MedicineUniversity of Michigan Health SystemAnn ArborMI
- Department of Computational Medicine and BioinformaticsUniversity of Michigan Medical SchoolAnn ArborMI
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Jozwiakowski SK, Kummer S, Gari K. Human DNA polymerase delta requires an iron-sulfur cluster for high-fidelity DNA synthesis. Life Sci Alliance 2019; 2:2/4/e201900321. [PMID: 31278166 PMCID: PMC6613617 DOI: 10.26508/lsa.201900321] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/26/2019] [Accepted: 06/27/2019] [Indexed: 01/10/2023] Open
Abstract
The iron–sulfur cluster in human DNA polymerase delta has an impact on DNA polymerase and exonuclease activities and can hence influence the fidelity of DNA synthesis. Replication of eukaryotic genomes relies on the family B DNA polymerases Pol α, Pol δ, and Pol ε. All of these enzymes coordinate an iron–sulfur (FeS) cluster, but the function of this cofactor has remained largely unclear. Here, we show that the FeS cluster in the catalytic subunit of human Pol δ is coordinated by four invariant cysteines of the C-terminal CysB motif. FeS cluster loss causes a partial destabilisation of the four-subunit enzyme, a defect in double-stranded DNA binding, and compromised polymerase and exonuclease activities. Importantly, complex stability, DNA binding, and enzymatic activities are restored in the presence of proliferating cell nuclear antigen. We further show that also more subtle changes to the FeS cluster-binding pocket that do not abolish FeS cluster binding can have repercussions on the distant exonuclease domain and render the enzyme error-prone. Our data hence suggest that the FeS cluster in human Pol δ is an important co-factor that despite its C-terminal location has an impact on both DNA polymerase and exonuclease activities, and can influence the fidelity of DNA synthesis.
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Affiliation(s)
| | - Sandra Kummer
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Kerstin Gari
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
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55
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Resende ATP, Martins CS, Bueno AC, Moreira AC, Foss-Freitas MC, de Castro M. Phenotypic diversity and glucocorticoid sensitivity in patients with familial partial lipodystrophy type 2. Clin Endocrinol (Oxf) 2019; 91:94-103. [PMID: 30954027 DOI: 10.1111/cen.13984] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 03/19/2019] [Accepted: 04/03/2019] [Indexed: 01/07/2023]
Abstract
UNLABELLED Familial partial lipodystrophy type 2 (FPLD2) is characterized by insulin resistance, adipose atrophy of the extremities and central obesity. Due to the resemblance with Cushing's syndrome, we hypothesized a putative role of glucocorticoid in the pathogenesis of metabolic abnormalities in FPLD2. OBJECTIVE To evaluate the phenotypic heterogeneity and glucocorticoid sensitivity in FPLD2 patients exhibiting the p.R482W or p.R644C LMNA mutations. DESIGN, PATIENTS AND MEASUREMENTS Prospective study with FPLD2 patients (n = 24) and controls (n = 24), who underwent anthropometric, body composition, metabolic profile and adipokines/cytokine plasma measurements. Plasma and salivary cortisol were measured in basal conditions and after 0.25, 0.5 and 1.0 mg of dexamethasone (DEX) given at 23:00 hours. Glucocorticoid receptor (GR) and 11βHSD isoforms expression were assessed by qPCR. RESULTS Familial partial lipodystrophy type 2 individuals presented increased waist and neck circumferences, decreased hip circumference, peripheral skinfold thickness and fat mass. Patients presented increased HOMA-IR, triglycerides, TNF-α, IL-1β, IL-6 and IL-10, and decreased adiponectin and leptin plasma levels. FPLD2 patients showed decreased ability to suppress the HPA axis compared with controls after 0.5 mg DEX. The phenotype was more pronounced in patients harbouring the p.R482W LMNA mutation. GRβ overexpression in PBMC was observed in female patients compared with female controls. CONCLUSIONS Familial partial lipodystrophy type 2 patients exhibited anthropometric, clinical and biochemical phenotypic heterogeneity related to LMNA mutation sites and to gender. LMNA mutations affecting both lamin A and lamin C lead to more severe phenotype. FPLD2 patients also showed blunted HPA axis response to DEX, probably due to the association of increased levels of proinflammatory cytokines with GRβ overexpression leading to a more severe phenotype in female.
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Affiliation(s)
- Ana Teresa Prata Resende
- Department of Internal Medicine, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, Brazil
| | - Clarissa Silva Martins
- Department of Internal Medicine, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, Brazil
| | - Ana Carolina Bueno
- Department of Pediatrics, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, Brazil
| | - Ayrton Custódio Moreira
- Department of Internal Medicine, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, Brazil
| | - Maria Cristina Foss-Freitas
- Department of Internal Medicine, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, Brazil
| | - Margaret de Castro
- Department of Internal Medicine, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, Brazil
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56
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Polyzos SA, Perakakis N, Mantzoros CS. Fatty liver in lipodystrophy: A review with a focus on therapeutic perspectives of adiponectin and/or leptin replacement. Metabolism 2019; 96:66-82. [PMID: 31071311 DOI: 10.1016/j.metabol.2019.05.001] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/23/2019] [Accepted: 05/03/2019] [Indexed: 01/17/2023]
Abstract
Lipodystrophy is a group of clinically heterogeneous, inherited or acquired, disorders characterized by complete or partial absence of subcutaneous adipose tissue that may occur simultaneously with the pathological, ectopic, accumulation of fat in other regions of the body, including the liver. Fatty liver adds significantly to hepatic and extra-hepatic morbidity in patients with lipodystrophy. Lipodystrophy is strongly associated with severe insulin resistance and related comorbidities, such as hyperglycemia, hyperlipidemia and nonalcoholic fatty liver disease (NAFLD), but other hepatic diseases may co-exist in some types of lipodystrophy, including autoimmune hepatitis in acquired lipodystrophies, or viral hepatitis in human immunodeficiency virus (HIV)-associated lipodystrophy. The aim of this review is to summarize evidence linking lipodystrophy with hepatic disease and to provide a special focus on potential therapeutic perspectives of leptin replacement therapy and adiponectin upregulation in lipodystrophy.
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Affiliation(s)
- Stergios A Polyzos
- First Department of Pharmacology, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
| | - Nikolaos Perakakis
- Department of Internal Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Christos S Mantzoros
- Department of Internal Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Section of Endocrinology, Boston VA Healthcare System, Harvard Medical School, Boston, MA, USA
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57
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Corvillo F, Akinci B. An overview of lipodystrophy and the role of the complement system. Mol Immunol 2019; 112:223-232. [PMID: 31177059 DOI: 10.1016/j.molimm.2019.05.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 05/28/2019] [Accepted: 05/29/2019] [Indexed: 12/19/2022]
Abstract
The complement system is a major component of innate immunity playing essential roles in the destruction of pathogens, the clearance of apoptotic cells and immune complexes, the enhancement of phagocytosis, inflammation, and the modulation of adaptive immune responses. During the last decades, numerous studies have shown that the complement system has key functions in the biology of certain tissues. For example, complement contributes to normal brain and embryonic development and to the homeostasis of lipid metabolism. However, the complement system is subjected to the effective balance between activation-inactivation to maintain complement homeostasis and to prevent self-injury to cells or tissues. When this control is disrupted, serious pathologies eventually develop, such as C3 glomerulopathy, autoimmune conditions and infections. Another heterogeneous group of ultra-rare diseases in which complement abnormalities have been described are the lipodystrophy syndromes. These diseases are characterized by the loss of adipose tissue throughout the entire body or partially. Complement over-activation has been reported in most of the patients with acquired partial lipodystrophy (also called Barraquer-Simons Syndrome) and in some cases of the generalized variety of the disease (Lawrence Syndrome). Even so, the mechanism through which the complement system induces adipose tissue abnormalities remains unclear. This review focuses on describing the link between the complement system and certain forms of lipodystrophy. In addition, we present an overview regarding the clinical presentation, differential diagnosis, classification, and management of patients with lipodystrophy associated with complement abnormalities.
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Affiliation(s)
- F Corvillo
- Complement Research Group, La Paz University Hospital Research Institute (IdiPAZ), La Paz University Hospital, Madrid, Spain; Center for Biomedical Network Research on Rare Diseases (CIBERER U754), Madrid, Spain.
| | - B Akinci
- Division of Endocrinology, Department of Internal Medicine, Dokuz Eylul University, Izmir, Turkey; Brehm Center for Diabetes Research, Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, 1000 Wall Street, Room 5313, Ann Arbor, MI, 48105, USA
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58
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Baranova A, Maltseva D, Tonevitsky A. Adipose may actively delay progression of NAFLD by releasing tumor-suppressing, anti-fibrotic miR-122 into circulation. Obes Rev 2019; 20:108-118. [PMID: 30248223 DOI: 10.1111/obr.12765] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 08/07/2018] [Accepted: 08/09/2018] [Indexed: 12/12/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common liver pathology. Here we propose tissue-cooperative, homeostatic model of NAFLD. During early stages of NAFLD the intrahepatic production of miR-122 falls, while the secretion of miRNA-containing exosomes by adipose increases. Bloodstream carries exosome to the liver, where their miRNA cargo is released to regulate their intrahepatic targets. When the deterioration of adipose catches up with the failing hepatic parenchyma, the external supply of liver-supporting miRNAs gradually tapers off, leading to the fibrotic decompensation of the liver and an increase in hepatic carcinogenesis. This model may explain paradoxical observations of the disease-associated decrease in intrahepatic production of certain miRNAs with an increase in their levels in serum. Infusions of miR-122 and, possibly, some other miRNAs may be efficient for preventing NAFLD-associated hepatocellular carcinoma. The best candidates for exosome-wrapped miRNA producer are adipose tissue-derived mesenchymal stem cells (MSCs), known for their capacity to shed large amounts of exosomes into the media. Notably, MSC-derived exosomes with no specific loading are already tested in patients with liver fibrosis. Carrier exosomes may be co-manufactured along with their cargo. Exosome-delivered miRNA cocktails may augment functioning of human organs suffering from a variety of chronic diseases.
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Affiliation(s)
- A Baranova
- School of Systems Biology, George Mason University, Fairfax, VA, USA.,Research Center for Medical Genetics, Moscow, Russia
| | - D Maltseva
- Department of Fundamental Medicine, School of Biomedicine, Far Eastern Federal University (FEFU), Vladivostok, Russia.,Scientific Research Center Bioclinicum (SRC Bioclinicum), Moscow, Russia
| | - A Tonevitsky
- Scientific Research Center Bioclinicum (SRC Bioclinicum), Moscow, Russia.,Higher School of Economics, Moscow, Russia
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59
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Akinci B, Meral R, Oral EA. Phenotypic and Genetic Characteristics of Lipodystrophy: Pathophysiology, Metabolic Abnormalities, and Comorbidities. Curr Diab Rep 2018; 18:143. [PMID: 30406415 DOI: 10.1007/s11892-018-1099-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE OF REVIEW This article focuses on recent progress in understanding the genetics of lipodystrophy syndromes, the pathophysiology of severe metabolic abnormalities caused by these syndromes, and causes of severe morbidity and a possible signal of increased mortality associated with lipodystrophy. An updated classification scheme is also presented. RECENT FINDINGS Lipodystrophy encompasses a group of heterogeneous rare diseases characterized by generalized or partial lack of adipose tissue and associated metabolic abnormalities including altered lipid metabolism and insulin resistance. Recent advances in the field have led to the discovery of new genes associated with lipodystrophy and have also improved our understanding of adipose biology, including differentiation, lipid droplet assembly, and metabolism. Several registries have documented the natural history of the disease and the serious comorbidities that patients with lipodystrophy face. There is also evolving evidence for increased mortality rates associated with lipodystrophy. Lipodystrophy syndromes represent a challenging cluster of diseases that lead to severe insulin resistance, a myriad of metabolic abnormalities, and serious morbidity. The understanding of these syndromes is evolving in parallel with the identification of novel disease-causing mechanisms.
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Affiliation(s)
- Baris Akinci
- Brehm Center for Diabetes Research, Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, 1000 Wall Street, Room 5313, Ann Arbor, MI, 48105, USA
- Division of Endocrinology, Department of Internal Medicine, Dokuz Eylul University, Izmir, Turkey
| | - Rasimcan Meral
- Brehm Center for Diabetes Research, Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, 1000 Wall Street, Room 5313, Ann Arbor, MI, 48105, USA
| | - Elif Arioglu Oral
- Brehm Center for Diabetes Research, Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, 1000 Wall Street, Room 5313, Ann Arbor, MI, 48105, USA.
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Fiorillo C, D'Apice MR, Trucco F, Murdocca M, Spitalieri P, Assereto S, Baratto S, Morcaldi G, Minetti C, Sangiuolo F, Novelli G. Characterization of MDPL Fibroblasts Carrying the Recurrent p.Ser605del Mutation in POLD1 Gene. DNA Cell Biol 2018; 37:1061-1067. [PMID: 30388038 DOI: 10.1089/dna.2018.4335] [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] [Indexed: 01/16/2023] Open
Abstract
Mandibular hypoplasia, deafness, and progeroid features, with concomitant lipodystrophy, define a multisystem disorder named MDPL syndrome. MDPL has been associated with heterozygous mutations in POLD1 gene resulting in loss of DNA polymerase δ activity. In this study, we report clinical, genetic, and cellular studies of a 13-year-old Pakistani girl, presenting growth retardation, sensorineural deafness, altered distribution of subcutaneous adipose tissue, and insulin resistance. We performed Sanger sequencing of POLD1 gene in the proband and the healthy parents. Fibroblasts obtained from dermal biopsy were evaluated for the specific hallmarks of cellular senescence and for their response to the DNA-induced damage. Patient carried the recurrent heterozygous de novo in frame deletion (c.1812_1814delCTC, p.Ser605del ) within POLD1 gene, previously detected in 16 MDPL patients. In patient's fibroblasts we observed severe nuclear envelope anomalies, presence of micronuclei, accumulation of prelamin A, altered cell growth, and cellular senescence. In addition, we observed a persistence of DNA damage after cisplatin exposure, compared to control cells. In conclusion, the MDPL nuclear and cellular findings resemble features observed in other progeroid syndromes and familial lipodystrophies. Although further investigations will be necessary, these information could be used to establish targeted therapeutic approaches.
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Affiliation(s)
- Chiara Fiorillo
- 1 Paediatric Neurology and Neuromuscular Disorders, University of Genoa and Istituto G. Gaslini , Genoa, Italy
| | | | - Federica Trucco
- 1 Paediatric Neurology and Neuromuscular Disorders, University of Genoa and Istituto G. Gaslini , Genoa, Italy
| | - Michela Murdocca
- 3 Department of Biomedicine and Prevention, University of Rome "Tor Vergata ," Rome, Italy
| | - Paola Spitalieri
- 3 Department of Biomedicine and Prevention, University of Rome "Tor Vergata ," Rome, Italy
| | - Stefania Assereto
- 1 Paediatric Neurology and Neuromuscular Disorders, University of Genoa and Istituto G. Gaslini , Genoa, Italy
| | - Serena Baratto
- 1 Paediatric Neurology and Neuromuscular Disorders, University of Genoa and Istituto G. Gaslini , Genoa, Italy
| | - Guido Morcaldi
- 1 Paediatric Neurology and Neuromuscular Disorders, University of Genoa and Istituto G. Gaslini , Genoa, Italy
| | - Carlo Minetti
- 1 Paediatric Neurology and Neuromuscular Disorders, University of Genoa and Istituto G. Gaslini , Genoa, Italy
| | - Federica Sangiuolo
- 2 Laboratory of Medical Genetics, Tor Vergata Hospital , Rome, Italy
- 3 Department of Biomedicine and Prevention, University of Rome "Tor Vergata ," Rome, Italy
| | - Giuseppe Novelli
- 2 Laboratory of Medical Genetics, Tor Vergata Hospital , Rome, Italy
- 3 Department of Biomedicine and Prevention, University of Rome "Tor Vergata ," Rome, Italy
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61
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Meral R, Ryan BJ, Malandrino N, Jalal A, Neidert AH, Muniyappa R, Akıncı B, Horowitz JF, Brown RJ, Oral EA. "Fat Shadows" From DXA for the Qualitative Assessment of Lipodystrophy: When a Picture Is Worth a Thousand Numbers. Diabetes Care 2018; 41:2255-2258. [PMID: 30237235 PMCID: PMC6150431 DOI: 10.2337/dc18-0978] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/09/2018] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Lipodystrophy syndromes are a heterogeneous group of disorders associated with selective absence of fat. Currently, the diagnosis is established only clinically. RESEARCH DESIGN AND METHODS We developed a new method from DXA scans called a "fat shadow," which is a color-coded representation highlighting only the fat tissue. We conducted a blinded retrospective validation study to assess its usefulness for the diagnosis of lipodystrophy syndromes. RESULTS We evaluated the fat shadows from 16 patients (11 female and 5 male) with generalized lipodystrophy (GL), 57 (50 female and 7 male) with familial partial lipodystrophy (FPLD), 2 (1 female and 1 male) with acquired partial lipodystrophy, and 126 (90 female and 36 male) control subjects. FPLD was differentiated from control subjects with 85% sensitivity and 96% specificity (95% CIs 72-93 and 91-99, respectively). GL was differentiated from nonobese control subjects with 100% sensitivity and specificity (95% CIs 79-100 and 92-100, respectively). CONCLUSIONS Fat shadows provided sufficient qualitative information to infer clinical phenotype and differentiate these patients from appropriate control subjects. We propose that this method could be used to support the diagnosis.
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Affiliation(s)
- Rasimcan Meral
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - Benjamin J Ryan
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, MI
| | - Noemi Malandrino
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Abdelwahab Jalal
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - Adam H Neidert
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - Ranganath Muniyappa
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD.,Inter-Institute Endocrinology Training Program, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Barış Akıncı
- Division of Endocrinology, Dokuz Eylül University, Izmir, Turkey
| | - Jeffrey F Horowitz
- Substrate Metabolism Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, MI
| | - Rebecca J Brown
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Elif A Oral
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
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Godoy-Matos AF, Valerio CM, Moreira RO, Momesso DP, Bittencourt LK. Pancreatic fat deposition is increased and related to beta-cell function in women with familial partial lipodystrophy. Diabetol Metab Syndr 2018; 10:71. [PMID: 30275911 PMCID: PMC6158829 DOI: 10.1186/s13098-018-0375-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 09/24/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND To study pancreatic fat deposition and beta-cell function in familial partial lipodystrophy (FPLD) patients. METHODS In a cross-sectional study, eleven patients with FPLD, and eight healthy volunteers were matched for age and body mass index and studied at a referral center. Body composition was assessed using dual-energy X-ray absorptiometry and the Dixon method of magnetic resonance imaging was used to quantify pancreatic and liver fat. Fasting plasma glucose, insulin, leptin, lipids and homeostasis model assessment of insulin resistance values were measured, and an oral glucose tolerance test was performed. The insulinogenic index, Matsuda insulin sensitivity index and beta-cell disposition index were calculated. RESULTS The FPLD group presented a higher waist-to-hip ratio and fat mass ratio and lower total, truncal and lower-limb fat masses. Pancreatic and liver fat contents (log transformed) were significantly higher in the FPLD group (5.26 ± 1.5 vs. 4.08 ± 0.64, p = 0.034 and 0.77 ± 0.50 vs. 0.41 ± 0.18, p = 0.056, respectively). Pancreatic fat was inversely related to the DI (r = - 0.53, p = 0.027) and HDL-cholesterol (r = - 0.63, p = 0.003) and directly related to WHR (r = 0.60; p = 0.009), HbA1c (r = 0.58; p = 0.01) and serum triglyceride (r = 0.48, p = 0.034). Higher triglyceride and lower HDL-cholesterol levels were observed in the FPLD group. CONCLUSIONS This study demonstrated for the first time that pancreatic fat deposition is increased in FPLD. Moreover, an inverse relationship was demonstrated between pancreatic fat and beta-cell function. The findings of this study may be consistent with the expandability hypothesis and the twin cycle hypothesis.
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Affiliation(s)
- Amelio F. Godoy-Matos
- Serviço de Metabologia, Instituto Estadual de Diabetes e Endocrinologia (IEDE), Rua Visconde Silva, 52/1135 Botafogo, Rio de Janeiro, 22271-090 Brazil
| | - Cynthia M. Valerio
- Serviço de Metabologia, Instituto Estadual de Diabetes e Endocrinologia (IEDE), Rua Visconde Silva, 52/1135 Botafogo, Rio de Janeiro, 22271-090 Brazil
| | - Rodrigo O. Moreira
- Serviço de Metabologia, Instituto Estadual de Diabetes e Endocrinologia (IEDE), Rua Visconde Silva, 52/1135 Botafogo, Rio de Janeiro, 22271-090 Brazil
| | - Denise P. Momesso
- Serviço de Metabologia, Instituto Estadual de Diabetes e Endocrinologia (IEDE), Rua Visconde Silva, 52/1135 Botafogo, Rio de Janeiro, 22271-090 Brazil
| | - Leonardo K. Bittencourt
- Departamento de Radiologia, Universidade Federal Fluminense-Section Head, Abdominal and Pelvic Imaging-CDPI Clinics, DASA Company, Rio de Janeiro, Brazil
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63
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Chung S. Body composition analysis and references in children: clinical usefulness and limitations. Eur J Clin Nutr 2018; 73:236-242. [PMID: 30258101 DOI: 10.1038/s41430-018-0322-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 09/06/2018] [Indexed: 12/18/2022]
Abstract
The prevalence of obesity is increasing over the world. Especially in Asians compared to Caucasians, there has been a significant increase in the population with major chronic diseases. This has developed over a shorter time period which is associated with socioeconomic changes in recent decades and a greater predisposition to cardiometabolic disorders. Many Asians could be classified has having normal weight but with obesity as evidenced by body composition (BC) and fat distribution. Overweight in Asian adults is classified as a BMI > 23 kg/m2 and obesity as a BMI > 25 kg/m2. An effective strategy to manage the obesity epidemic by focusing on childhood obesity is needed because of the huge impact that obesity exerts on population health. However, monitoring tools are limited to anthropometry such as BMI and BMI z-scores which define overweight and obese as a BMI exceeding the 85th and 95th percentiles, respectively, on reference growth charts. To overcome the limitations of BMI, reference values for BC components have been produced using various techniques. The use of BC charts for children in personalized therapeutic approach has increased, although there is a lack of a consensus on a single reference technique. Zones on BC charts and the personalized values of BC components could be practical, especially for the detection of metabolically unhealthy normal weight (MUN) children. BC charts should be included in the growth chart package and BC monitoring through the entire life course will help us understand the association between growth, aging, health and disease.
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Affiliation(s)
- Sochung Chung
- Department of Pediatrics, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea.
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64
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Brady GF, Kwan R, Cunha JB, Elenbaas JS, Omary MB. Lamins and Lamin-Associated Proteins in Gastrointestinal Health and Disease. Gastroenterology 2018; 154:1602-1619.e1. [PMID: 29549040 PMCID: PMC6038707 DOI: 10.1053/j.gastro.2018.03.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/04/2018] [Accepted: 03/06/2018] [Indexed: 02/07/2023]
Abstract
The nuclear lamina is a multi-protein lattice composed of A- and B-type lamins and their associated proteins. This protein lattice associates with heterochromatin and integral inner nuclear membrane proteins, providing links among the genome, nucleoskeleton, and cytoskeleton. In the 1990s, mutations in EMD and LMNA were linked to Emery-Dreifuss muscular dystrophy. Since then, the number of diseases attributed to nuclear lamina defects, including laminopathies and other disorders, has increased to include more than 20 distinct genetic syndromes. Studies of patients and mouse genetic models have pointed to important roles for lamins and their associated proteins in the function of gastrointestinal organs, including liver and pancreas. We review the interactions and functions of the lamina in relation to the nuclear envelope and genome, the ways in which its dysfunction is thought to contribute to human disease, and possible avenues for targeted therapies.
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Affiliation(s)
- Graham F. Brady
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan,Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan,To whom correspondence should be addressed: University of Michigan Medical School, Division of Gastroenterology, Department of Internal Medicine, 1137 Catherine St., Ann Arbor, MI 48109-5622.
| | - Raymond Kwan
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Juliana Bragazzi Cunha
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Jared S. Elenbaas
- Medical Scientist Training Program, Washington University, St Louis, Missouri
| | - M. Bishr Omary
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan,Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan,Ǻbo Akademi University, Turku, Finland
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65
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Brady GF, Kwan R, Ulintz PJ, Nguyen P, Bassirian S, Basrur V, Nesvizhskii AI, Loomba R, Omary MB. Nuclear lamina genetic variants, including a truncated LAP2, in twins and siblings with nonalcoholic fatty liver disease. Hepatology 2018; 67:1710-1725. [PMID: 28902428 PMCID: PMC5849478 DOI: 10.1002/hep.29522] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Revised: 08/15/2017] [Accepted: 09/07/2017] [Indexed: 01/03/2023]
Abstract
UNLABELLED Nonalcoholic fatty liver disease (NAFLD) is becoming the major chronic liver disease in many countries. Its pathogenesis is multifactorial, but twin and familial studies indicate significant heritability, which is not fully explained by currently known genetic susceptibility loci. Notably, mutations in genes encoding nuclear lamina proteins, including lamins, cause lipodystrophy syndromes that include NAFLD. We hypothesized that variants in lamina-associated proteins predispose to NAFLD and used a candidate gene-sequencing approach to test for variants in 10 nuclear lamina-related genes in a cohort of 37 twin and sibling pairs: 21 individuals with and 53 without NAFLD. Twelve heterozygous sequence variants were identified in four lamina-related genes (ZMPSTE24, TMPO, SREBF1, SREBF2). The majority of NAFLD patients (>90%) had at least one variant compared to <40% of controls (P < 0.0001). When only insertions/deletions and changes in conserved residues were considered, the difference between the groups was similarly striking (>80% versus <25%; P < 0.0001). Presence of a lamina variant segregated with NAFLD independently of the PNPLA3 I148M polymorphism. Several variants were found in TMPO, which encodes the lamina-associated polypeptide-2 (LAP2) that has not been associated with liver disease. One of these, a frameshift insertion that generates truncated LAP2, abrogated lamin-LAP2 binding, caused LAP2 mislocalization, altered endogenous lamin distribution, increased lipid droplet accumulation after oleic acid treatment in transfected cells, and led to cytoplasmic association with the ubiquitin-binding protein p62/SQSTM1. CONCLUSION Several variants in nuclear lamina-related genes were identified in a cohort of twins and siblings with NAFLD; one such variant, which results in a truncated LAP2 protein and a dramatic phenotype in cell culture, represents an association of TMPO/LAP2 variants with NAFLD and underscores the potential importance of the nuclear lamina in NAFLD. (Hepatology 2018;67:1710-1725).
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Affiliation(s)
- Graham F. Brady
- Department of Molecular and Integrative Physiology and Department of Internal Medicine, University of Michigan,To whom correspondence should be addressed: University of Michigan Medical School, Division of Gastroenterology, Department of Internal Medicine, 1137 Catherine St., Ann Arbor, MI 48109-5622.
| | - Raymond Kwan
- Department of Molecular and Integrative Physiology and Department of Internal Medicine, University of Michigan
| | - Peter J. Ulintz
- Department of Computational Medicine and Bioinformatics, University of Michigan
| | - Phirum Nguyen
- NAFLD Research Center, Division of Gastroenterology, Department of Medicine, University of California, San Diego
| | - Shirin Bassirian
- NAFLD Research Center, Division of Gastroenterology, Department of Medicine, University of California, San Diego
| | - Venkatesha Basrur
- Department of Computational Medicine and Bioinformatics, University of Michigan
| | - Alexey I. Nesvizhskii
- Department of Computational Medicine and Bioinformatics, University of Michigan,Department of Pathology, University of Michigan
| | - Rohit Loomba
- NAFLD Research Center, Division of Gastroenterology, Department of Medicine, University of California, San Diego
| | - M. Bishr Omary
- Department of Molecular and Integrative Physiology and Department of Internal Medicine, University of Michigan
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66
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Sahinoz M, Khairi S, Cuttitta A, Brady GF, Rupani A, Meral R, Tayeh MK, Thomas P, Riebschleger M, Camelo-Piragua S, Innis JW, Bishr Omary M, Michele DE, Oral EA. Potential association of LMNA-associated generalized lipodystrophy with juvenile dermatomyositis. Clin Diabetes Endocrinol 2018; 4:6. [PMID: 29610677 PMCID: PMC5870259 DOI: 10.1186/s40842-018-0058-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 03/20/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Juvenile dermatomyositis (JDM) is an auto-immune muscle disease which presents with skin manifestations and muscle weakness. At least 10% of the patients with JDM present with acquired lipodystrophy. Laminopathies are caused by mutations in the lamin genes and cover a wide spectrum of diseases including muscular dystrophies and lipodystrophy. The p.T10I LMNA variant is associated with a phenotype of generalized lipodystrophy that has also been called atypical progeroid syndrome. CASE PRESENTATION A previously healthy female presented with bilateral proximal lower extremity muscle weakness at age 4. She was diagnosed with JDM based on her clinical presentation, laboratory tests and magnetic resonance imaging (MRI). She had subcutaneous fat loss which started in her extremities and progressed to her whole body. At age 7, she had diabetes, hypertriglyceridemia, low leptin levels and low body fat on dual energy X-ray absorptiometry (DEXA) scan, and was diagnosed with acquired generalized lipodystrophy (AGL). Whole exome sequencing (WES) revealed a heterozygous c.29C > T; p.T10I missense pathogenic variant in LMNA, which encodes lamins A and C. Muscle biopsy confirmed JDM rather than muscular dystrophy, showing perifascicular atrophy and perivascular mononuclear cell infiltration. Immunofluroscence of skin fibroblasts confirmed nuclear atypia and fragmentation. CONCLUSIONS This is a unique case with p.T10I LMNA variant displaying concurrent JDM and AGL. This co-occurrence raises the intriguing possibility that LMNA, and possibly p.T10I, may have a pathogenic role in not only the occurrence of generalized lipodystrophy, but also juvenile dermatomyositis. Careful phenotypic characterization of additional patients with laminopathies as well as individuals with JDM is warranted.
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Affiliation(s)
- Melis Sahinoz
- Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Shafaq Khairi
- Metabolism Endocrinology and Diabetes Division, Department of Internal Medicine, University of Michigan and Brehm Center for Diabetes, 1000 Wall Street, Room 5313, Ann Arbor, MI MI48105 USA
| | - Ashley Cuttitta
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI USA
| | - Graham F. Brady
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI USA
| | - Amit Rupani
- Division of Genetics, Metabolism & Genomic Medicine, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI USA
| | - Rasimcan Meral
- Metabolism Endocrinology and Diabetes Division, Department of Internal Medicine, University of Michigan and Brehm Center for Diabetes, 1000 Wall Street, Room 5313, Ann Arbor, MI MI48105 USA
| | - Marwan K. Tayeh
- Division of Genetics, Metabolism & Genomic Medicine, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI USA
| | - Peedikayil Thomas
- Division of Genetics, Metabolism & Genomic Medicine, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI USA
| | - Meredith Riebschleger
- Division of Pediatric Rheumatology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI USA
| | | | - Jeffrey W. Innis
- Division of Genetics, Metabolism & Genomic Medicine, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI USA
- Department of Human Genetics, University of Michigan, Ann Arbor, MI USA
| | - M. Bishr Omary
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI USA
| | - Daniel E. Michele
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI USA
| | - Elif A. Oral
- Metabolism Endocrinology and Diabetes Division, Department of Internal Medicine, University of Michigan and Brehm Center for Diabetes, 1000 Wall Street, Room 5313, Ann Arbor, MI MI48105 USA
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67
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Sasaki H, Yanagi K, Ugi S, Kobayashi K, Ohkubo K, Tajiri Y, Maegawa H, Kashiwagi A, Kaname T. Definitive diagnosis of mandibular hypoplasia, deafness, progeroid features and lipodystrophy (MDPL) syndrome caused by a recurrent de novo mutation in the POLD1 gene. Endocr J 2018; 65:227-238. [PMID: 29199204 DOI: 10.1507/endocrj.ej17-0287] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Segmental progeroid syndromes with lipodystrophy are extremely rare, heterogeneous, and complex multi-system disorders that are characterized by phenotypic features of premature aging affecting various tissues and organs. In this study, we present a "sporadic/isolated" Japanese woman who was ultimately diagnosed with mandibular hypoplasia, deafness, progeroid features, and progressive lipodystrophy (MDPL) syndrome (MIM #615381) using whole exome sequencing analysis. She had been suspected as having atypical Werner syndrome and/or progeroid syndrome based on observations spanning a 30-year period; however, repeated genetic testing by Sanger sequencing did not identify any causative mutation related to various subtypes of congenital partial lipodystrophy (CPLD) and/or mandibular dysplasia with lipodystrophy (MAD). Recently, MDPL syndrome has been described as a new entity showing progressive lipodystrophy. Furthermore, polymerase delta 1 (POLD1) gene mutations on chromosome 19 have been identified in patients with MDPL syndrome. To date, 21 cases with POLD1-related MDPL syndrome have been reported worldwide, albeit almost entirely of European origin. Here, we identified a de novo mutation in exon 15 (p.Ser605del) of the POLD1 gene in a Japanese case by whole exome sequencing. To the best of our knowledge, this is the first identified case of MDPL syndrome in Japan. Our results provide further evidence that mutations in POLD1 are responsible for MDPL syndrome and serve as a common genetic determinant across different ethnicities.
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Affiliation(s)
- Haruka Sasaki
- Department of Endocrinology and Diabetes Mellitus, Fukuoka University Chikushi Hospital, Chikushino, Fukuoka 818-8502, Japan
- Division of Diabetic Medicine, Bunyukai Hara Hospital, Ohnojo, Fukuoka 816-0943, Japan
| | - Kumiko Yanagi
- Department of Genome Medicine, National Research Institute for Child Health, Setagaya, Tokyo 157-8535, Japan
| | - Satoshi Ugi
- Department of Medicine, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan
| | - Kunihisa Kobayashi
- Department of Endocrinology and Diabetes Mellitus, Fukuoka University Chikushi Hospital, Chikushino, Fukuoka 818-8502, Japan
| | - Kumiko Ohkubo
- Department of Laboratory Medicine, School of Medicine, Fukuoka University, Jonan-ku, Fukuoka 814-0180, Japan
| | - Yuji Tajiri
- Division of Endocrinology and Metabolism, Kurume University School of Medicine, Kurume, Fukuoka 830-0111, Japan
| | - Hiroshi Maegawa
- Department of Medicine, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan
| | - Atsunori Kashiwagi
- Diabetes Center, Seikokai Kusatsu General Hospital, Kusatsu, Shiga 525-8585, Japan
| | - Tadashi Kaname
- Department of Genome Medicine, National Research Institute for Child Health, Setagaya, Tokyo 157-8535, Japan
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68
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Kwan R, Brady GF, Brzozowski M, Weerasinghe SV, Martin H, Park MJ, Brunt MJ, Menon RK, Tong X, Yin L, Stewart CL, Omary MB. Hepatocyte-Specific Deletion of Mouse Lamin A/C Leads to Male-Selective Steatohepatitis. Cell Mol Gastroenterol Hepatol 2017; 4:365-383. [PMID: 28913408 PMCID: PMC5582719 DOI: 10.1016/j.jcmgh.2017.06.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 06/30/2017] [Indexed: 01/01/2023]
Abstract
BACKGROUND & AIMS Lamins are nuclear intermediate filament proteins that comprise the major components of the nuclear lamina. Mutations in LMNA, which encodes lamins A/C, cause laminopathies, including lipodystrophy, cardiomyopathy, and premature aging syndromes. However, the role of lamins in the liver is unknown, and it is unclear whether laminopathy-associated liver disease is caused by primary hepatocyte defects or systemic alterations. METHODS To address these questions, we generated mice carrying a hepatocyte-specific deletion of Lmna (knockout [KO] mice) and characterized the KO liver and primary hepatocyte phenotypes by immunoblotting, immunohistochemistry, microarray analysis, quantitative real-time polymerase chain reaction, and Oil Red O and Picrosirius red staining. RESULTS KO hepatocytes manifested abnormal nuclear morphology, and KO mice showed reduced body mass. KO mice developed spontaneous male-selective hepatosteatosis with increased susceptibility to high-fat diet-induced steatohepatitis and fibrosis. The hepatosteatosis was associated with up-regulated transcription of genes encoding lipid transporters, lipid biosynthetic enzymes, lipid droplet-associated proteins, and interferon-regulated genes. Hepatic Lmna deficiency led to enhanced signal transducer and activator of transcription 1 (Stat1) expression and blocked growth hormone-mediated Janus kinase 2 (Jak2), signal transducer and activator of transcription 5 (Stat5), and extracellular signal-regulated kinase (Erk) signaling. CONCLUSIONS Lamin A/C acts cell-autonomously to maintain hepatocyte homeostasis and nuclear shape and buffers against male-selective steatohepatitis by positively regulating growth hormone signaling and negatively regulating Stat1 expression. Lamins are potential genetic modifiers for predisposition to steatohepatitis and liver fibrosis. The microarray data can be found in the Gene Expression Omnibus repository (accession number: GSE93643).
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Key Words
- % liver weight, liver percentage of body mass
- Erk, extracellular signal–regulated kinase
- FPLD2, Dunnigan familial partial lipodystrophy
- Fibrosis
- GH, growth hormone
- Growth Hormone Signaling
- HFD, high-fat diet
- Het, heterozygous
- Igf1, insulin-like growth factor 1
- Jak2, Janus kinase 2
- KO, knockout
- Laminopathy
- Lipodystrophy
- NAFLD, nonalcoholic fatty liver disease
- ND, normal diet
- Nonalcoholic Fatty Liver Disease
- PBS, phosphate-buffered saline
- Stat, signal transducer and activator of transcription
- WT, wild type
- qPCR, quantitative polymerase chain reaction
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Affiliation(s)
- Raymond Kwan
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan,Correspondence Address correspondence to: Raymond Kwan, Department of Molecular and Integrative Physiology, University of Michigan, 7720 Med Sci II, Ann Arbor, Michigan 48109.Department of Molecular and Integrative PhysiologyUniversity of Michigan7720 Med Sci IIAnn ArborMichigan 48109
| | - Graham F. Brady
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan,Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Maria Brzozowski
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Sujith V. Weerasinghe
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Hope Martin
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Min-Jung Park
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Makayla J. Brunt
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Ram K. Menon
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Xin Tong
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Lei Yin
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan,Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Colin L. Stewart
- Development and Regenerative Biology Group, Institute of Medical Biology, Immunos, Singapore
| | - M. Bishr Omary
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan,Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
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69
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Oral EA, Reilly SM, Gomez AV, Meral R, Butz L, Ajluni N, Chenevert TL, Korytnaya E, Neidert AH, Hench R, Rus D, Horowitz JF, Poirier B, Zhao P, Lehmann K, Jain M, Yu R, Liddle C, Ahmadian M, Downes M, Evans RM, Saltiel AR. Inhibition of IKKɛ and TBK1 Improves Glucose Control in a Subset of Patients with Type 2 Diabetes. Cell Metab 2017; 26:157-170.e7. [PMID: 28683283 PMCID: PMC5663294 DOI: 10.1016/j.cmet.2017.06.006] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 04/06/2017] [Accepted: 06/13/2017] [Indexed: 12/12/2022]
Abstract
Numerous studies indicate an inflammatory link between obesity and type 2 diabetes. The inflammatory kinases IKKɛ and TBK1 are elevated in obesity; their inhibition in obese mice reduces weight, insulin resistance, fatty liver and inflammation. Here we studied amlexanox, an inhibitor of IKKɛ and TBK1, in a proof-of-concept randomized, double-blind, placebo-controlled study of 42 obese patients with type 2 diabetes and nonalcoholic fatty liver disease. Treatment of patients with amlexanox produced a statistically significant reduction in Hemoglobin A1c and fructosamine. Interestingly, a subset of drug responders also exhibited improvements in insulin sensitivity and hepatic steatosis. This subgroup was characterized by a distinct inflammatory gene expression signature from biopsied subcutaneous fat at baseline. They also exhibited a unique pattern of gene expression changes in response to amlexanox, consistent with increased energy expenditure. Together, these data suggest that dual-specificity inhibitors of IKKɛ and TBK1 may be effective therapies for metabolic disease in an identifiable subset of patients.
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Affiliation(s)
- Elif A Oral
- Division of Metabolism, Endocrinology, and Diabetes, Department of Medicine, and Brehm Center for Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA.
| | - Shannon M Reilly
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Departments of Medicine and Pharmacology, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Andrew V Gomez
- Departments of Medicine and Pharmacology, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Rasimcan Meral
- Division of Metabolism, Endocrinology, and Diabetes, Department of Medicine, and Brehm Center for Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Laura Butz
- Division of Metabolism, Endocrinology, and Diabetes, Department of Medicine, and Brehm Center for Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Nevin Ajluni
- Division of Metabolism, Endocrinology, and Diabetes, Department of Medicine, and Brehm Center for Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Thomas L Chenevert
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Evgenia Korytnaya
- Division of Metabolism, Endocrinology, and Diabetes, Department of Medicine, and Brehm Center for Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Adam H Neidert
- Division of Metabolism, Endocrinology, and Diabetes, Department of Medicine, and Brehm Center for Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Rita Hench
- Division of Metabolism, Endocrinology, and Diabetes, Department of Medicine, and Brehm Center for Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Diana Rus
- Division of Metabolism, Endocrinology, and Diabetes, Department of Medicine, and Brehm Center for Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | | | - BreAnne Poirier
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Peng Zhao
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Departments of Medicine and Pharmacology, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Kim Lehmann
- Departments of Medicine and Pharmacology, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Mohit Jain
- Departments of Medicine and Pharmacology, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Ruth Yu
- Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA 92037, USA
| | - Christopher Liddle
- Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA 92037, USA; Storr Liver Centre, Westmead Institute for Medical Research and Sydney Medical School, University of Sydney, Westmead Hospital, Westmead, NSW 2145, Australia
| | - Maryam Ahmadian
- Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA 92037, USA
| | - Michael Downes
- Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA 92037, USA
| | - Ronald M Evans
- Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA 92037, USA
| | - Alan R Saltiel
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Departments of Medicine and Pharmacology, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA; Institute of Diabetes and Metabolic Health, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0757, USA.
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70
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Akinci B, Onay H, Demir T, Savas-Erdeve Ş, Gen R, Simsir IY, Keskin FE, Erturk MS, Uzum AK, Yaylali GF, Ozdemir NK, Atik T, Ozen S, Yurekli BS, Apaydin T, Altay C, Akinci G, Demir L, Comlekci A, Secil M, Oral EA. Clinical presentations, metabolic abnormalities and end-organ complications in patients with familial partial lipodystrophy. Metabolism 2017; 72:109-119. [PMID: 28641778 DOI: 10.1016/j.metabol.2017.04.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/18/2017] [Accepted: 04/23/2017] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Familial partial lipodystrophy (FPLD) is a rare genetic disorder characterized by partial lack of subcutaneous fat. METHODS This multicenter prospective observational study included data from 56 subjects with FPLD (18 independent Turkish families). Thirty healthy controls were enrolled for comparison. RESULTS Pathogenic variants of the LMNA gene were determined in nine families. Of those, typical exon 8 codon 482 pathogenic variants were identified in four families. Analysis of the LMNA gene also revealed exon 1 codon 47, exon 5 codon 306, exon 6 codon 349, exon 9 codon 528, and exon 11 codon 582 pathogenic variants. Analysis of the PPARG gene revealed exon 3 p.Y151C pathogenic variant in two families and exon 7 p.H477L pathogenic variant in one family. A non-pathogenic exon 5 p.R215Q variant of the LMNB2 gene was detected in another family. Five other families harbored no mutation in any of the genes sequenced. MRI studies showed slightly different fat distribution patterns among subjects with different point mutations, though it was strikingly different in subjects with LMNA p.R349W pathogenic variant. Subjects with pathogenic variants of the PPARG gene were associated with less prominent fat loss and relatively higher levels of leptin compared to those with pathogenic variants in the LMNA gene. Various metabolic abnormalities associated with insulin resistance were detected in all subjects. End-organ complications were observed. CONCLUSION We have identified various pathogenic variants scattered throughout the LMNA and PPARG genes in Turkish patients with FPLD. Phenotypic heterogeneity is remarkable in patients with LMNA pathogenic variants related to the site of missense mutations. FPLD, caused by pathogenic variants either in LMNA or PPARG is associated with metabolic abnormalities associated with insulin resistance that lead to increased morbidity.
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Affiliation(s)
- Baris Akinci
- Division of Endocrinology, Dokuz Eylul University, Izmir, Turkey.
| | - Huseyin Onay
- Department of Medical Genetics, Ege University, Izmir, Turkey
| | - Tevfik Demir
- Division of Endocrinology, Dokuz Eylul University, Izmir, Turkey
| | - Şenay Savas-Erdeve
- Division of Pediatric Endocrinology, Dr. Sami Ulus Obstetrics and Gynecology, Children's Health and Disease Training and Research Hospital, Ankara, Turkey
| | - Ramazan Gen
- Division of Endocrinology, Mersin University, Mersin, Turkey
| | | | - Fatma Ela Keskin
- Division of Endocrinology, Cerrahpasa Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | | | - Ayse Kubat Uzum
- Division of Endocrinology, Capa Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | | | | | - Tahir Atik
- Division of Pediatric Genetics, Ege University, Izmir, Turkey
| | - Samim Ozen
- Division of Pediatric Endocrinology, Ege University, Izmir, Turkey
| | | | - Tugce Apaydin
- Division of Endocrinology, Cerrahpasa Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Canan Altay
- Department of Radiology, Dokuz Eylul University, Izmir, Turkey
| | - Gulcin Akinci
- Division of Pediatric Neurology, Dr.Behcet Uz Children's Hospital, Izmir, Turkey
| | - Leyla Demir
- Department of Biochemistry, Ataturk Training Hospital, Izmir, Turkey
| | | | - Mustafa Secil
- Department of Radiology, Dokuz Eylul University, Izmir, Turkey
| | - Elif Arioglu Oral
- Division of Endocrinology and Metabolism, Brehm Center for Diabetes Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
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Omary MB. Intermediate filament proteins of digestive organs: physiology and pathophysiology. Am J Physiol Gastrointest Liver Physiol 2017; 312:G628-G634. [PMID: 28360031 PMCID: PMC5495917 DOI: 10.1152/ajpgi.00455.2016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/21/2017] [Accepted: 03/22/2017] [Indexed: 01/31/2023]
Abstract
Intermediate filament proteins (IFs), such as cytoplasmic keratins in epithelial cells and vimentin in mesenchymal cells and the nuclear lamins, make up one of the three major cytoskeletal protein families. Whether in digestive organs or other tissues, IFs share several unique features including stress-inducible overexpression, abundance, cell-selective and differentiation state expression, and association with >80 human diseases when mutated. Whereas most IF mutations cause disease, mutations in simple epithelial keratins 8, 18, or 19 or in lamin A/C predispose to liver disease with or without other tissue manifestations. Keratins serve major functions including protection from apoptosis, providing cellular and subcellular mechanical integrity, protein targeting to subcellular compartments, and scaffolding and regulation of cell-signaling processes. Keratins are essential for Mallory-Denk body aggregate formation that occurs in association with several liver diseases, whereas an alternate type of keratin and lamin aggregation occurs upon liver involvement in porphyria. IF-associated diseases have no known directed therapy, but high-throughput drug screening to identify potential therapies is an appealing ongoing approach. Despite the extensive current knowledge base, much remains to be discovered regarding IF physiology and pathophysiology in digestive and nondigestive organs.
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Affiliation(s)
- M. Bishr Omary
- Department of Molecular and Integrative Physiology and Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
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72
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Elouej S, Beleza-Meireles A, Caswell R, Colclough K, Ellard S, Desvignes JP, Béroud C, Lévy N, Mohammed S, De Sandre-Giovannoli A. Exome sequencing reveals a de novo POLD1 mutation causing phenotypic variability in mandibular hypoplasia, deafness, progeroid features, and lipodystrophy syndrome (MDPL). Metabolism 2017; 71:213-225. [PMID: 28521875 DOI: 10.1016/j.metabol.2017.03.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 03/17/2017] [Accepted: 03/21/2017] [Indexed: 01/19/2023]
Abstract
BACKGROUND Mandibular hypoplasia, deafness, progeroid features, and lipodystrophy syndrome (MDPL) is an autosomal dominant systemic disorder characterized by prominent loss of subcutaneous fat, a characteristic facial appearance and metabolic abnormalities. This syndrome is caused by heterozygous de novo mutations in the POLD1 gene. To date, 19 patients with MDPL have been reported in the literature and among them 14 patients have been characterized at the molecular level. Twelve unrelated patients carried a recurrent in-frame deletion of a single codon (p.Ser605del) and two other patients carried a novel heterozygous mutation in exon 13 (p.Arg507Cys). Additionally and interestingly, germline mutations of the same gene have been involved in familial polyposis and colorectal cancer (CRC) predisposition. PATIENTS AND METHODS We describe a male and a female patient with MDPL respectively affected with mild and severe phenotypes. Both of them showed mandibular hypoplasia, a beaked nose with bird-like facies, prominent eyes, a small mouth, growth retardation, muscle and skin atrophy, but the female patient showed such a severe and early phenotype that a first working diagnosis of Hutchinson-Gilford Progeria was made. The exploration was performed by direct sequencing of POLD1 gene exon 15 in the male patient with a classical MDPL phenotype and by whole exome sequencing in the female patient and her unaffected parents. RESULTS Exome sequencing identified in the latter patient a de novo heterozygous undescribed mutation in the POLD1 gene (NM_002691.3: c.3209T>A), predicted to cause the missense change p.Ile1070Asn in the ZnF2 (Zinc Finger 2) domain of the protein. This mutation was not reported in the 1000 Genome Project, dbSNP and Exome sequencing databases. Furthermore, the Isoleucine1070 residue of POLD1 is highly conserved among various species, suggesting that this substitution may cause a major impairment of POLD1 activity. For the second patient, affected with a typical MDPL phenotype, direct sequencing of POLD1 exon 15 revealed the recurrent in-frame deletion (c.1812_1814del, p.S605del). CONCLUSION Our work highlights that mutations in different POLD1 domains can lead to phenotypic variability, ranging from dominantly inherited cancer predisposition syndromes, to mild MDPL phenotypes without lifespan reduction, to very severe MDPL syndromes with major premature aging features. These results also suggest that POLD1 gene testing should be considered in patients presenting with severe progeroid features.
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Affiliation(s)
- Sahar Elouej
- Aix Marseille Univ, INSERM, GMGF, Marseille, France
| | - Ana Beleza-Meireles
- Department of Clinical Genetics, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Richard Caswell
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK
| | - Kevin Colclough
- Department of Molecular Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Sian Ellard
- Department of Molecular Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | | | - Christophe Béroud
- Aix Marseille Univ, INSERM, GMGF, Marseille, France; Department of Medical Genetics, Molecular genetics Laboratory, La Timone Children's Hospital, 264 Rue Saint Pierre, 13005, Marseille, France
| | - Nicolas Lévy
- Aix Marseille Univ, INSERM, GMGF, Marseille, France; Department of Medical Genetics, Molecular genetics Laboratory, La Timone Children's Hospital, 264 Rue Saint Pierre, 13005, Marseille, France
| | - Shehla Mohammed
- Department of Clinical Genetics, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Annachiara De Sandre-Giovannoli
- Aix Marseille Univ, INSERM, GMGF, Marseille, France; Department of Medical Genetics, Molecular genetics Laboratory, La Timone Children's Hospital, 264 Rue Saint Pierre, 13005, Marseille, France.
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