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Willis J, Lefterova MI, Artyomenko A, Kasi PM, Nakamura Y, Mody K, Catenacci DVT, Fakih M, Barbacioru C, Zhao J, Sikora M, Fairclough SR, Lee H, Kim KM, Kim ST, Kim J, Gavino D, Benavides M, Peled N, Nguyen T, Cusnir M, Eskander RN, Azzi G, Yoshino T, Banks KC, Raymond VM, Lanman RB, Chudova DI, Talasaz A, Kopetz S, Lee J, Odegaard JI. Validation of Microsatellite Instability Detection Using a Comprehensive Plasma-Based Genotyping Panel. Clin Cancer Res 2019; 25:7035-7045. [PMID: 31383735 DOI: 10.1158/1078-0432.ccr-19-1324] [Citation(s) in RCA: 137] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 05/15/2019] [Accepted: 07/10/2019] [Indexed: 12/24/2022]
Abstract
PURPOSE To analytically and clinically validate microsatellite instability (MSI) detection using cell-free DNA (cfDNA) sequencing. EXPERIMENTAL DESIGN Pan-cancer MSI detection using Guardant360 was analytically validated according to established guidelines and clinically validated using 1,145 cfDNA samples for which tissue MSI status based on standard-of-care tissue testing was available. The landscape of cfDNA-based MSI across solid tumor types was investigated in a cohort of 28,459 clinical plasma samples. Clinical outcomes for 16 patients with cfDNA MSI-H gastric cancer treated with immunotherapy were evaluated. RESULTS cfDNA MSI evaluation was shown to have high specificity, precision, and sensitivity, with a limit of detection of 0.1% tumor content. In evaluable patients, cfDNA testing accurately detected 87% (71/82) of tissue MSI-H and 99.5% of tissue microsatellite stable (863/867) for an overall accuracy of 98.4% (934/949) and a positive predictive value of 95% (71/75). Concordance of cfDNA MSI with tissue PCR and next-generation sequencing was significantly higher than IHC. Prevalence of cfDNA MSI for major cancer types was consistent with those reported for tissue. Finally, robust clinical activity of immunotherapy treatment was seen in patients with advanced gastric cancer positive for MSI by cfDNA, with 63% (10/16) of patients achieving complete or partial remission with sustained clinical benefit. CONCLUSIONS cfDNA-based MSI detection using Guardant360 is highly concordant with tissue-based testing, enabling highly accurate detection of MSI status concurrent with comprehensive genomic profiling and expanding access to immunotherapy for patients with advanced cancer for whom current testing practices are inadequate.See related commentary by Wang and Ajani, p. 6887.
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Affiliation(s)
- Jason Willis
- The University of Texas MD Anderson Cancer Center, Houston, Texas
| | | | | | - Pashtoon Murtaza Kasi
- Division of Oncology/Hematology, Department of Internal Medicine, University of Iowa, Iowa City, Iowa
| | - Yoshiaki Nakamura
- Department of Gastroenterology and Gastrointestinal Oncology, National Cancer Center Hospital East, Kashiwa, Japan
| | - Kabir Mody
- Division of Hematology and Medical Oncology, Mayo Clinic, Jacksonville, Florida
| | | | - Marwan Fakih
- Medical Oncology, City of Hope, Duarte, California
| | | | - Jing Zhao
- Guardant Health, Redwood City, California
| | | | | | - Hyuk Lee
- Division of Gastroenterology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Kyoung-Mee Kim
- Division of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Seung Tae Kim
- Division of Hematology-Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Jinchul Kim
- Division of Hematology-Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | | | - Manuel Benavides
- Medical Oncology, Hospital Universitario Virgen de la Victoria, Malaga, Spain
| | - Nir Peled
- Division of Medical Oncology, Rabin Medical Center, Petach Tiqea, Israel
| | - Timmy Nguyen
- Hematology/Oncology, Cleveland Clinic Foundation, Weston, Florida
| | - Mike Cusnir
- Comprehensive Cancer Center, Mount Sinai Medical Center, Miami Beach, Florida
| | - Ramez N Eskander
- Center for Personalized Cancer Therapy, Division of Gynecologic Oncology, University of California San Diego Health Moores Cancer Center, La Jolla, California
| | - Georges Azzi
- Medical Oncology, Holy Cross Michael & Dianne Bienes Comprehensive Cancer Center, Fort Lauderdale, Florida
| | - Takayuki Yoshino
- Department of Gastroenterology and Gastrointestinal Oncology, National Cancer Center Hospital East, Kashiwa, Japan
| | | | | | | | | | | | - Scott Kopetz
- The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Jeeyun Lee
- Division of Hematology-Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
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Tan SK, Shen P, Lefterova MI, Sahoo MK, Fung E, Odegaard JI, Davis RW, Pinsky BA, Scharfe C. Transplant Virus Detection Using Multiplex Targeted Sequencing. J Appl Lab Med 2017; 2:757-769. [PMID: 31245786 DOI: 10.1373/jalm.2017.024521] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Background Viral infections are a major cause of complications and death in solid organ and hematopoietic cell transplantation. Methods We developed a multiplex viral sequencing assay (mVseq) to simultaneously detect 20 transplant-relevant DNA viruses from small clinical samples. The assay uses a single-tube multiplex PCR to amplify highly conserved virus genomic regions without the need for previous virus enrichment or host nucleic acid subtraction. Multiplex sample sequencing was performed using Illumina MiSeq, and reads were aligned to a database of target sequences. Analytical and clinical performance was evaluated using reference viruses spiked into human plasma, as well as patient plasma and nonplasma samples, including bronchoalveolar lavage fluid, cerebrospinal fluid, urine, and tissue from immunocompromised transplant recipients. Results For the virus spike-in samples, mVseq's analytical sensitivity and dynamic range were similar to quantitative PCR (qPCR). In clinical specimens, mVseq showed substantial agreement with single-target qPCR (92%; k statistic, 0.77; 259 of 282 viral tests); however, clinical sensitivity was reduced (81%), ranging from 62% to 100% for specific viruses. In 12 of the 47 patients tested, mVseq identified previously unknown BK virus, human herpesvirus-7, and Epstein-Barr virus infections that were confirmed by qPCR. Conclusions Our results reveal factors that can influence clinical sensitivity, such as high levels of host DNA background and loss of detection in coinfections when 1 virus was at much higher concentration than the others. The mVseq assay is flexible and scalable to incorporate RNA viruses, emerging viruses of interest, and other pathogens important in transplant recipients.
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Affiliation(s)
- Susanna K Tan
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA
| | - Peidong Shen
- Stanford Genome Technology Center, Stanford University, Palo Alto, CA
| | - Martina I Lefterova
- Department of Pathology, Stanford University School of Medicine, Palo Alto, CA
| | - Malaya K Sahoo
- Department of Pathology, Stanford University School of Medicine, Palo Alto, CA
| | - Eula Fung
- Stanford Genome Technology Center, Stanford University, Palo Alto, CA
| | - Justin I Odegaard
- Department of Pathology, Stanford University School of Medicine, Palo Alto, CA
| | - Ronald W Davis
- Stanford Genome Technology Center, Stanford University, Palo Alto, CA
| | - Benjamin A Pinsky
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA.,Department of Pathology, Stanford University School of Medicine, Palo Alto, CA
| | - Curt Scharfe
- Department of Genetics, Yale University School of Medicine, New Haven, CT
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Tan SK, Shen P, Lefterova MI, Sahoo MK, Odegaard J, Pinsky B, Scharfe C. Multiplex Detection of DNA Viruses in Transplant Recipients. Open Forum Infect Dis 2017. [DOI: 10.1093/ofid/ofx163.1953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Lefterova MI, Shen P, Odegaard JI, Fung E, Chiang T, Peng G, Davis RW, Wang W, Kharrazi M, Schrijver I, Scharfe C. Next-Generation Molecular Testing of Newborn Dried Blood Spots for Cystic Fibrosis. J Mol Diagn 2016; 18:267-82. [PMID: 26847993 DOI: 10.1016/j.jmoldx.2015.11.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Revised: 10/21/2015] [Accepted: 11/19/2015] [Indexed: 12/19/2022] Open
Abstract
Newborn screening for cystic fibrosis enables early detection and management of this debilitating genetic disease. Implementing comprehensive CFTR analysis using Sanger sequencing as a component of confirmatory testing of all screen-positive newborns has remained impractical due to relatively lengthy turnaround times and high cost. Here, we describe CFseq, a highly sensitive, specific, rapid (<3 days), and cost-effective assay for comprehensive CFTR gene analysis from dried blood spots, the common newborn screening specimen. The unique design of CFseq integrates optimized dried blood spot sample processing, a novel multiplex amplification method from as little as 1 ng of genomic DNA, and multiplex next-generation sequencing of 96 samples in a single run to detect all relevant CFTR mutation types. Sequence data analysis utilizes publicly available software supplemented by an expert-curated compendium of >2000 CFTR variants. Validation studies across 190 dried blood spots demonstrated 100% sensitivity and a positive predictive value of 100% for single-nucleotide variants and insertions and deletions and complete concordance across the polymorphic poly-TG and consecutive poly-T tracts. Additionally, we accurately detected both a known exon 2,3 deletion and a previously undetected exon 22,23 deletion. CFseq is thus able to replace all existing CFTR molecular assays with a single robust, definitive assay at significant cost and time savings and could be adapted to high-throughput screening of other inherited conditions.
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Affiliation(s)
- Martina I Lefterova
- Department of Pathology, Stanford University Medical Center, Stanford, California
| | - Peidong Shen
- Stanford Genome Technology Center, Stanford University, Palo Alto, California
| | - Justin I Odegaard
- Department of Pathology, Stanford University Medical Center, Stanford, California
| | - Eula Fung
- Department of Pathology, Stanford University Medical Center, Stanford, California
| | - Tsoyu Chiang
- Department of Pathology, Stanford University Medical Center, Stanford, California
| | - Gang Peng
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Ronald W Davis
- Stanford Genome Technology Center, Stanford University, Palo Alto, California
| | - Wenyi Wang
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Martin Kharrazi
- California Department of Public Health, Environmental Health Investigations Branch, Richmond, California
| | - Iris Schrijver
- Department of Pathology, Stanford University Medical Center, Stanford, California; Department of Pediatrics, Stanford University Medical Center, Stanford, California
| | - Curt Scharfe
- Department of Pathology, Stanford University Medical Center, Stanford, California; Stanford Genome Technology Center, Stanford University, Palo Alto, California.
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Lefterova MI, Suarez CJ, Banaei N, Pinsky BA. Next-Generation Sequencing for Infectious Disease Diagnosis and Management: A Report of the Association for Molecular Pathology. J Mol Diagn 2015; 17:623-34. [PMID: 26433313 DOI: 10.1016/j.jmoldx.2015.07.004] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 05/27/2015] [Accepted: 07/02/2015] [Indexed: 12/31/2022] Open
Abstract
Next-generation sequencing (NGS) technologies are increasingly being used for diagnosis and monitoring of infectious diseases. Herein, we review the application of NGS in clinical microbiology, focusing on genotypic resistance testing, direct detection of unknown disease-associated pathogens in clinical specimens, investigation of microbial population diversity in the human host, and strain typing. We have organized the review into three main sections: i) applications in clinical virology, ii) applications in clinical bacteriology, mycobacteriology, and mycology, and iii) validation, quality control, and maintenance of proficiency. Although NGS holds enormous promise for clinical infectious disease testing, many challenges remain, including automation, standardizing technical protocols and bioinformatics pipelines, improving reference databases, establishing proficiency testing and quality control measures, and reducing cost and turnaround time, all of which would be necessary for widespread adoption of NGS in clinical microbiology laboratories.
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Affiliation(s)
- Martina I Lefterova
- Association for Molecular Pathology Next-Generation Sequencing in Infectious Disease Work Group, Bethesda, Maryland; Department of Pathology, Stanford University School of Medicine, Stanford, California
| | - Carlos J Suarez
- Association for Molecular Pathology Next-Generation Sequencing in Infectious Disease Work Group, Bethesda, Maryland; Department of Pathology, Stanford University School of Medicine, Stanford, California
| | - Niaz Banaei
- Association for Molecular Pathology Next-Generation Sequencing in Infectious Disease Work Group, Bethesda, Maryland; Department of Pathology, Stanford University School of Medicine, Stanford, California; Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California
| | - Benjamin A Pinsky
- Association for Molecular Pathology Next-Generation Sequencing in Infectious Disease Work Group, Bethesda, Maryland; Department of Pathology, Stanford University School of Medicine, Stanford, California; Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California.
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LeBlanc RE, Lefterova MI, Suarez CJ, Tavallaee M, Kim YH, Schrijver I, Kim J, Gratzinger D. Lymph node involvement by mycosis fungoides and Sézary syndrome mimicking angioimmunoblastic T-cell lymphoma. Hum Pathol 2015; 46:1382-9. [PMID: 26193796 DOI: 10.1016/j.humpath.2015.05.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 05/28/2015] [Accepted: 05/29/2015] [Indexed: 10/23/2022]
Abstract
Clinical management of cutaneous T-cell lymphoma (CTCL) and angioimmunoblastic T-cell lymphoma (AITL) differs markedly. Diagnostic distinction is critical. Herein, we describe a series of 4 patients with clinically, molecularly, and histopathologically annotated mycosis fungoides or Sézary syndrome whose nodal disease mimicked AITL. The patients otherwise exhibited classic clinical manifestations of mycosis fungoides/Sézary syndrome preceding the onset of lymphadenopathy by 1 to 5 years. Skin biopsies revealed epidermotropic infiltrates characteristic of CTCL. Lymph node biopsies revealed dense CD4+ T-cell infiltrates that coexpressed follicular helper T-cell markers and were accompanied by proliferations of high endothelial venules and arborizing CD21+ follicular dendritic cell networks. Two patients had T-cell receptor gene rearrangement studies performed on their skin, lymph node, and peripheral blood demonstrating identical polymerase chain reaction clones in all 3 tissues. A small secondary clonal B-cell population was present in 1 patient that mimicked the B-cell proliferations known to accompany AITL and persisted on successive nodal biopsies over several years. This latter phenomenon has not previously been described in CTCL. The potential for patients to be misdiagnosed with AITL for lack of consideration of advanced-stage CTCL with nodal involvement underscores the necessity of information sharing among the various pathologists and clinicians involved in the care of each patient.
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Affiliation(s)
- Robert E LeBlanc
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305
| | - Martina I Lefterova
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305
| | - Carlos J Suarez
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305
| | - Mahkam Tavallaee
- Department of Dermatology, Stanford University School of Medicine, Stanford, CA 94305
| | - Youn H Kim
- Department of Dermatology, Stanford University School of Medicine, Stanford, CA 94305
| | - Iris Schrijver
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305
| | - Jinah Kim
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305
| | - Dita Gratzinger
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305.
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Lefterova MI, Haakonsson AK, Lazar MA, Mandrup S. PPARγ and the global map of adipogenesis and beyond. Trends Endocrinol Metab 2014; 25:293-302. [PMID: 24793638 PMCID: PMC4104504 DOI: 10.1016/j.tem.2014.04.001] [Citation(s) in RCA: 413] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 04/08/2014] [Accepted: 04/09/2014] [Indexed: 10/25/2022]
Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is a member of the nuclear receptor (NR) superfamily of ligand-dependent transcription factors (TFs) and function as a master regulator of adipocyte differentiation and metabolism. We review recent breakthroughs in the understanding of PPARγ gene regulation and function in the chromatin context. It is now clear that multiple TFs team up to induce PPARγ during adipogenesis, and that other TFs cooperate with PPARγ to ensure adipocyte-specific genomic binding and function. We discuss how this differs in other PPARγ-expressing cells such as macrophages and how these genome-wide mechanisms are preserved across species despite modest conservation of specific binding sites. These emerging considerations inform our understanding of PPARγ function as well as of adipocyte development and physiology.
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Affiliation(s)
- Martina I Lefterova
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA; Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, and Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anders K Haakonsson
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark
| | - Mitchell A Lazar
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, and Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Susanne Mandrup
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark.
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Roszer T, Menéndez-Gutiérrez MP, Lefterova MI, Alameda D, Núñez V, Lazar MA, Fischer T, Ricote M. Autoimmune kidney disease and impaired engulfment of apoptotic cells in mice with macrophage peroxisome proliferator-activated receptor gamma or retinoid X receptor alpha deficiency. J Immunol 2010; 186:621-31. [PMID: 21135166 DOI: 10.4049/jimmunol.1002230] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Autoimmune glomerulonephritis is a common manifestation of systemic lupus erythematosus (SLE). In this study, we show that mice lacking macrophage expression of the heterodimeric nuclear receptors PPARγ or RXRα develop glomerulonephritis and autoantibodies to nuclear Ags, resembling the nephritis seen in SLE. These mice show deficiencies in phagocytosis and clearance of apoptotic cells, and they are unable to acquire an anti-inflammatory phenotype upon feeding of apoptotic cells, which is critical for the maintenance of self-tolerance. These results demonstrate that stimulation of PPARγ and RXRα in macrophages facilitates apoptotic cell engulfment, and they provide a potential strategy to avoid autoimmunity against dying cells and to attenuate SLE.
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Affiliation(s)
- Tamás Roszer
- Departamento de Cardiología Regenerativa, Centro Nacional de Investigaciones Cardiovasculares, 28029 Madrid, Spain
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9
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Steger DJ, Grant GR, Schupp M, Tomaru T, Lefterova MI, Schug J, Manduchi E, Stoeckert CJ, Lazar MA. Propagation of adipogenic signals through an epigenomic transition state. Genes Dev 2010; 24:1035-44. [PMID: 20478996 DOI: 10.1101/gad.1907110] [Citation(s) in RCA: 203] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The transcriptional mechanisms by which temporary exposure to developmental signals instigates adipocyte differentiation are unknown. During early adipogenesis, we find transient enrichment of the glucocorticoid receptor (GR), CCAAT/enhancer-binding protein beta (CEBPbeta), p300, mediator subunit 1, and histone H3 acetylation near genes involved in cell proliferation, development, and differentiation, including the gene encoding the master regulator of adipocyte differentiation, peroxisome proliferator-activated receptor gamma2 (PPARgamma2). Occupancy and enhancer function are triggered by adipogenic signals, and diminish upon their removal. GR, which is important for adipogenesis but need not be active in the mature adipocyte, functions transiently with other enhancer proteins to propagate a new program of gene expression that includes induction of PPARgamma2, thereby providing a memory of the earlier adipogenic signal. Thus, the conversion of preadipocyte to adipocyte involves the formation of an epigenomic transition state that is not observed in cells at the beginning or end of the differentiation process.
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Affiliation(s)
- David J Steger
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Lefterova MI, Mullican SE, Tomaru T, Qatanani M, Schupp M, Lazar MA. Endoplasmic reticulum stress regulates adipocyte resistin expression. Diabetes 2009; 58:1879-86. [PMID: 19491212 PMCID: PMC2712799 DOI: 10.2337/db08-1706] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Accepted: 05/08/2009] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Resistin is a secreted polypeptide that impairs glucose metabolism and, in rodents, is derived exclusively from adipocytes. In murine obesity, resistin circulates at elevated levels but its gene expression in adipose tissue is paradoxically reduced. The mechanism behind the downregulation of resistin mRNA is poorly understood. We investigated whether endoplasmic reticulum (ER) stress, which is characteristic of obese adipose tissue, regulates resistin expression in cultured mouse adipocytes. RESEARCH DESIGN AND METHODS The effects of endoplasmic stress inducers on resistin mRNA and secreted protein levels were examined in differentiated 3T3-L1 adipocytes, focusing on the expression and genomic binding of transcriptional regulators of resistin. The association between downregulated resistin mRNA and induction of ER stress was also investigated in the adipose tissue of mice fed a high-fat diet. RESULTS ER stress reduced resistin mRNA in 3T3-L1 adipocytes in a time- and dose-dependent manner. The effects of ER stress were transcriptional because of downregulation of CAAT/enhancer binding protein-alpha and peroxisome proliferator-activated receptor-gamma transcriptional activators and upregulation of the transcriptional repressor CAAT/enhancer binding protein homologous protein-10 (CHOP10). Resistin protein was also substantially downregulated, showing a close correspondence with mRNA levels in 3T3-L1 adipocytes as well as in the fat pads of obese mice. CONCLUSIONS ER stress is a potent regulator of resistin, suggesting that ER stress may underlie the local downregulation of resistin mRNA and protein in fat in murine obesity. The paradoxical increase in plasma may be because of various systemic abnormalities associated with obesity and insulin resistance.
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Affiliation(s)
- Martina I. Lefterova
- From the Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine and Department of Genetics, and The Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Shannon E. Mullican
- From the Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine and Department of Genetics, and The Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Takuya Tomaru
- From the Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine and Department of Genetics, and The Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Mohammed Qatanani
- From the Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine and Department of Genetics, and The Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Michael Schupp
- From the Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine and Department of Genetics, and The Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Mitchell A. Lazar
- From the Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine and Department of Genetics, and The Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
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Abstract
The obesity epidemic has focused attention on adipose tissue and the development of fat cells (i.e. adipocytes), which is known as adipogenesis. Peroxisome proliferator-activated receptor gamma and CCAAT/enhancer-binding proteins have emerged as master regulators of adipogenesis, and recent genome-wide studies have indicated widespread overlap in their transcriptional targets. In addition, new evidence has implicated many other factors as positive and negative regulators of adipocyte development. This review highlights recent advances in the field of adipogenesis, including newly identified determinants of brown adipocytes, the function of which is to burn rather than store energy. Improved understanding of brown and white adipocyte origins and the integrative biology of adipogenesis might lead to more effective strategies for the treatment of obesity and metabolic disease.
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Affiliation(s)
- Martina I Lefterova
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine and The Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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12
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Lefterova MI, Zhang Y, Steger DJ, Schupp M, Schug J, Cristancho A, Feng D, Zhuo D, Stoeckert CJ, Liu XS, Lazar MA. PPARgamma and C/EBP factors orchestrate adipocyte biology via adjacent binding on a genome-wide scale. Genes Dev 2009; 22:2941-52. [PMID: 18981473 DOI: 10.1101/gad.1709008] [Citation(s) in RCA: 618] [Impact Index Per Article: 41.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Peroxisome proliferator-activated receptor gamma(PPARgamma), a nuclear receptor and the target of anti-diabetic thiazolinedione drugs, is known as the master regulator of adipocyte biology. Although it regulates hundreds of adipocyte genes, PPARgamma binding to endogenous genes has rarely been demonstrated. Here, utilizing chromatin immunoprecipitation (ChIP) coupled with whole genome tiling arrays, we identified 5299 genomic regions of PPARgamma binding in mouse 3T3-L1 adipocytes. The consensus PPARgamma/RXRalpha "DR-1"-binding motif was found at most of the sites, and ChIP for RXRalpha showed colocalization at nearly all locations tested. Bioinformatics analysis also revealed CCAAT/enhancer-binding protein (C/EBP)-binding motifs in the vicinity of most PPARgamma-binding sites, and genome-wide analysis of C/EBPalpha binding demonstrated that it localized to 3350 of the locations bound by PPARgamma. Importantly, most genes induced in adipogenesis were bound by both PPARgamma and C/EBPalpha, while very few were PPARgamma-specific. C/EBPbeta also plays a role at many of these genes, such that both C/EBPalpha and beta are required along with PPARgamma for robust adipocyte-specific gene expression. Thus, PPARgamma and C/EBP factors cooperatively orchestrate adipocyte biology by adjacent binding on an unanticipated scale.
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Affiliation(s)
- Martina I Lefterova
- Institute for Diabetes, Obesity, and Metabolism, and Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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Schupp M, Cristancho AG, Lefterova MI, Hanniman EA, Briggs ER, Steger DJ, Qatanani M, Curtin JC, Schug J, Ochsner SA, McKenna NJ, Lazar MA. Re-expression of GATA2 cooperates with peroxisome proliferator-activated receptor-gamma depletion to revert the adipocyte phenotype. J Biol Chem 2009; 284:9458-64. [PMID: 19136559 DOI: 10.1074/jbc.m809498200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Nuclear peroxisome proliferator-activated receptor-gamma (PPARgamma) is required for adipocyte differentiation, but its role in mature adipocytes is less clear. Here, we report that knockdown of PPARgamma expression in 3T3-L1 adipocytes returned the expression of most adipocyte genes to preadipocyte levels. Consistently, down-regulated but not up-regulated genes showed strong enrichment of PPARgamma binding. Surprisingly, not all adipocyte genes were reversed, and the adipocyte morphology was maintained for an extended period after PPARgamma depletion. To explain this, we focused on transcriptional regulators whose adipogenic regulation was not reversed upon PPARgamma depletion. We identified GATA2, a transcription factor whose down-regulation early in adipogenesis is required for preadipocyte differentiation and whose levels remain low after PPARgamma knockdown. Forced expression of GATA2 in mature adipocytes complemented PPARgamma depletion and impaired adipocyte functionality with a more preadipocyte-like gene expression profile. Ectopic expression of GATA2 in adipose tissue in vivo had a similar effect on adipogenic gene expression. These results suggest that PPARgamma-independent down-regulation of GATA2 prevents reversion of mature adipocytes after PPARgamma depletion.
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Affiliation(s)
- Michael Schupp
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Univ. of Pennsylvania School of Medicine, 700 CRB, 415 Curie Blvd., Philadelphia, PA 19104-6149, USA
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14
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Tomaru T, Steger DJ, Lefterova MI, Schupp M, Lazar MA. Adipocyte-specific expression of murine resistin is mediated by synergism between peroxisome proliferator-activated receptor gamma and CCAAT/enhancer-binding proteins. J Biol Chem 2009; 284:6116-25. [PMID: 19126543 DOI: 10.1074/jbc.m808407200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Resistin antagonizes insulin action in mouse, making it a potential therapeutic target for treating metabolic diseases such as diabetes. To better understand how mouse resistin gene (Retn) expression is restricted to fat tissue, we identified an adipocyte-specific enhancer located approximately 8.8-kb upstream of the transcription start site. This region contains a binding site for the master adipogenic regulator peroxisome proliferator-activated receptor gamma (PPARgamma), and binds endogenous PPARgamma together with its partner retinoid-X receptor alpha (RXRalpha). It also contains three binding sites for CCAAT/enhancer-binding protein (C/EBP), and is bound by endogenous C/EBPalpha and C/EBPbeta in adipocytes. Exogenous expression of PPARgamma/RXRalpha and C/EBPalpha in non-adipocyte cells synergistically drives robust expression from the enhancer. Although PPARgamma ligands repress Retn transcription in adipocytes, rosiglitazone paradoxically stimulates the enhancer activity, suggesting that the enhancer is not directly involved in negative regulation. Unlike expression of Retn in mouse, human resistin (RETN) is expressed primarily in macrophages. Interestingly, the region homologous to the mouse Retn enhancer in the human gene contains all three C/EBP elements, but is not conserved for the sequence bound by PPARgamma. Furthermore, it displays little or no binding by PPARgamma in vitro. Taken together, the data suggest that a composite enhancer binding both PPARgamma and C/EBP factors confers adipocyte-specific expression to Retn in mouse, and its absence from the human gene may explain the lack of adipocyte expression in humans.
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Affiliation(s)
- Takuya Tomaru
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, The Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6149, USA
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15
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McVay LD, Keilbaugh SA, Wong TM, Kierstein S, Shin ME, Lehrke M, Lefterova MI, Shifflett DE, Barnes SL, Cominelli F, Cohn SM, Hecht G, Lazar MA, Haczku A, Wu GD. Absence of bacterially induced RELMbeta reduces injury in the dextran sodium sulfate model of colitis. J Clin Invest 2006; 116:2914-23. [PMID: 17024245 PMCID: PMC1590268 DOI: 10.1172/jci28121] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Accepted: 08/15/2006] [Indexed: 12/15/2022] Open
Abstract
Although inflammatory bowel disease (IBD) is the result of a dysregulated immune response to commensal gut bacteria in genetically predisposed individuals, the mechanism(s) by which bacteria lead to the development of IBD are unknown. Interestingly, deletion of intestinal goblet cells protects against intestinal injury, suggesting that this epithelial cell lineage may produce molecules that exacerbate IBD. We previously reported that resistin-like molecule beta (RELMbeta; also known as FIZZ2) is an intestinal goblet cell-specific protein that is induced upon bacterial colonization whereupon it is expressed in the ileum and colon, regions of the gut most often involved in IBD. Herein, we show that disruption of this gene reduces the severity of colitis in the dextran sodium sulfate (DSS) model of murine colonic injury. Although RELMbeta does not alter colonic epithelial proliferation or barrier function, we show that recombinant protein activates macrophages to produce TNF-alpha both in vitro and in vivo. RELMbeta expression is also strongly induced in the terminal ileum of the SAMP1/Fc model of IBD. These results suggest a model whereby the loss of epithelial barrier function by DSS results in the activation of the innate mucosal response by RELMbeta located in the lumen, supporting the hypothesis that this protein is a link among goblet cells, commensal bacteria, and the pathogenesis of IBD.
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Affiliation(s)
- Laila D. McVay
- Division of Gastroenterology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Division of Gastroenterology, Hepatology and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Division of Pulmonary Allergy and Critical Care and
Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Medicine, Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
Digestive Health Center of Excellence, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - Sue A. Keilbaugh
- Division of Gastroenterology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Division of Gastroenterology, Hepatology and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Division of Pulmonary Allergy and Critical Care and
Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Medicine, Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
Digestive Health Center of Excellence, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - Tracie M.H. Wong
- Division of Gastroenterology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Division of Gastroenterology, Hepatology and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Division of Pulmonary Allergy and Critical Care and
Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Medicine, Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
Digestive Health Center of Excellence, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - Sonja Kierstein
- Division of Gastroenterology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Division of Gastroenterology, Hepatology and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Division of Pulmonary Allergy and Critical Care and
Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Medicine, Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
Digestive Health Center of Excellence, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - Marcus E. Shin
- Division of Gastroenterology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Division of Gastroenterology, Hepatology and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Division of Pulmonary Allergy and Critical Care and
Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Medicine, Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
Digestive Health Center of Excellence, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - Michael Lehrke
- Division of Gastroenterology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Division of Gastroenterology, Hepatology and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Division of Pulmonary Allergy and Critical Care and
Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Medicine, Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
Digestive Health Center of Excellence, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - Martina I. Lefterova
- Division of Gastroenterology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Division of Gastroenterology, Hepatology and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Division of Pulmonary Allergy and Critical Care and
Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Medicine, Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
Digestive Health Center of Excellence, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - D. Edward Shifflett
- Division of Gastroenterology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Division of Gastroenterology, Hepatology and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Division of Pulmonary Allergy and Critical Care and
Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Medicine, Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
Digestive Health Center of Excellence, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - Sean L. Barnes
- Division of Gastroenterology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Division of Gastroenterology, Hepatology and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Division of Pulmonary Allergy and Critical Care and
Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Medicine, Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
Digestive Health Center of Excellence, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - Fabio Cominelli
- Division of Gastroenterology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Division of Gastroenterology, Hepatology and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Division of Pulmonary Allergy and Critical Care and
Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Medicine, Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
Digestive Health Center of Excellence, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - Steven M. Cohn
- Division of Gastroenterology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Division of Gastroenterology, Hepatology and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Division of Pulmonary Allergy and Critical Care and
Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Medicine, Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
Digestive Health Center of Excellence, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - Gail Hecht
- Division of Gastroenterology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Division of Gastroenterology, Hepatology and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Division of Pulmonary Allergy and Critical Care and
Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Medicine, Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
Digestive Health Center of Excellence, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - Mitchell A. Lazar
- Division of Gastroenterology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Division of Gastroenterology, Hepatology and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Division of Pulmonary Allergy and Critical Care and
Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Medicine, Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
Digestive Health Center of Excellence, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - Angela Haczku
- Division of Gastroenterology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Division of Gastroenterology, Hepatology and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Division of Pulmonary Allergy and Critical Care and
Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Medicine, Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
Digestive Health Center of Excellence, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - Gary D. Wu
- Division of Gastroenterology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Division of Gastroenterology, Hepatology and Nutrition, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Division of Pulmonary Allergy and Critical Care and
Division of Endocrinology, Diabetes, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Medicine, Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
Digestive Health Center of Excellence, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
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16
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Lefterov IM, Koldamova RP, Lefterova MI, Schwartz DR, Lazo JS. Cysteine 73 in bleomycin hydrolase is critical for amyloid precursor protein processing. Biochem Biophys Res Commun 2001; 283:994-9. [PMID: 11350084 DOI: 10.1006/bbrc.2001.4860] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human bleomycin hydrolase (hBH) is a neutral cysteine protease that may regulate the secretion of soluble amyloid precursor protein (APP) and amyloid beta (A(beta)), which is a major constituent of the Alzheimer's disease-associated amyloid plaques. We have now determined that APP interacts with hBH by using yeast two hybrid methods and in vitro binding studies revealed that APP interacted with a 68 amino acid region that includes the catalytic domain of hBH. Ectopic expression of hBH increased the secretion of A(beta) but not of a second secreted protein, apolipoprotein A-I. Expression of hBH in which the catalytic cysteine 73 was mutated to serine failed to increase A(beta) secretion. These results indicate a critical role for cysteine 73 of hBH in mediating APP processing.
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Affiliation(s)
- I M Lefterov
- Department of Pharmacology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
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17
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Koldamova RP, Lefterov IM, Lefterova MI, Lazo JS. Apolipoprotein A-I directly interacts with amyloid precursor protein and inhibits A beta aggregation and toxicity. Biochemistry 2001; 40:3553-60. [PMID: 11297421 DOI: 10.1021/bi002186k] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Amyloid precursor protein (APP) is the source of the neurotoxic amyloid beta (Abeta) peptide associated with Alzheimer's disease. Apolipoprotein A-I (apoA-I), a constituent of high-density lipoprotein complexes, was identified by a yeast two-hybrid system as a strong and specific binding partner of full-length APP (APPfl). This association between apoA-I and APPfl was localized to the extracellular domain of APP (APPextra). Furthermore, the interaction between apoA-I and APPfl was confirmed by coprecipitation using recombinant epitope-tagged APPextra and purified apoA-I. Several functional domains have been identified in APPextra, and we focused on a possible interaction between apoA-1 and the pathologically important Abeta peptide, because APPextra contains the nontransmembrane domain of Abeta. The binding between apoA-I and Abeta was saturable (K(d) = 6 nM), specific, and reversible. APPextra also competed with apoA-I for binding to Abeta. Direct evidence for this interaction was obtained by the formation of an SDS-resistant Abeta-apoA-I complex in polyacrylamide gels. Competitive experiments with apolipoprotein E (isoforms E2 and E4) showed that apoA-I had a higher binding affinity for Abeta. We also found that apoA-I inhibited the beta-sheet formation of Abeta with a mean inhibitory concentration close to that of alpha2-macroglobulin. Finally, we demonstrated that apoA-I attenuated Abeta-induced cytotoxicity. These results suggest apoA-I binds to at least one extracellular domain of APP and has a functional role in controlling Abeta aggregation and toxicity.
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Affiliation(s)
- R P Koldamova
- Department of Pharmacology, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania 15261, USA
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