1
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Huang S, Shahine A, Cheng TY, Chen YL, Ng SW, Balaji GR, Farquhar R, Gras S, Hardman CS, Altman JD, Tahiri N, Minnaard AJ, Ogg GS, Mayfield JA, Rossjohn J, Moody DB. CD1 lipidomes reveal lipid-binding motifs and size-based antigen-display mechanisms. Cell 2023; 186:4583-4596.e13. [PMID: 37725977 PMCID: PMC10591967 DOI: 10.1016/j.cell.2023.08.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 05/05/2023] [Accepted: 08/21/2023] [Indexed: 09/21/2023]
Abstract
The CD1 system binds lipid antigens for display to T cells. Here, we solved lipidomes for the four human CD1 antigen-presenting molecules, providing a map of self-lipid display. Answering a basic question, the detection of >2,000 CD1-lipid complexes demonstrates broad presentation of self-sphingolipids and phospholipids. Whereas peptide antigens are chemically processed, many lipids are presented in an unaltered form. However, each type of CD1 protein differentially edits the self-lipidome to show distinct capture motifs based on lipid length and chemical composition, suggesting general antigen display mechanisms. For CD1a and CD1d, lipid size matches the CD1 cleft volume. CD1c cleft size is more variable, and CD1b is the outlier, where ligands and clefts show an extreme size mismatch that is explained by uniformly seating two small lipids in one cleft. Furthermore, the list of compounds that comprise the integrated CD1 lipidome supports the ongoing discovery of lipid blockers and antigens for T cells.
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Affiliation(s)
- Shouxiong Huang
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Adam Shahine
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
- Australian Research Council Centre of Excellence for Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Tan-Yun Cheng
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Yi-Ling Chen
- Human Immunology Unit, Weatherall Institute for Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK
- Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford, UK
| | - Soo Weei Ng
- Human Immunology Unit, Weatherall Institute for Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK
| | - Gautham R. Balaji
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Rachel Farquhar
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
- Australian Research Council Centre of Excellence for Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Stephanie Gras
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
- Australian Research Council Centre of Excellence for Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Clare S. Hardman
- Human Immunology Unit, Weatherall Institute for Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK
| | - John D. Altman
- Emory Vaccine Center, Emory School of Medicine, Atlanta, GA 30322, USA
| | - Nabil Tahiri
- Department of Chemical Biology, Stratingh Institute for Chemistry, Groningen, Netherlands
| | - Adriaan J. Minnaard
- Department of Chemical Biology, Stratingh Institute for Chemistry, Groningen, Netherlands
| | - Graham S. Ogg
- Human Immunology Unit, Weatherall Institute for Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK
- Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford, UK
| | - Jacob A. Mayfield
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jamie Rossjohn
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
- Australian Research Council Centre of Excellence for Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
- Institute of Infection and Immunity, Cardiff University, School of Medicine, Heath Park, Cardiff CF14 4XN, UK
| | - D. Branch Moody
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Lead contact
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2
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Prithviraj M, Kado T, Mayfield JA, Young DC, Huang AD, Motooka D, Nakamura S, Siegrist MS, Moody DB, Morita YS. Tuberculostearic Acid Controls Mycobacterial Membrane Compartmentalization. mBio 2023; 14:e0339622. [PMID: 36976029 PMCID: PMC10127668 DOI: 10.1128/mbio.03396-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 03/08/2023] [Indexed: 03/29/2023] Open
Abstract
The intracellular membrane domain (IMD) is a laterally discrete region of the mycobacterial plasma membrane, enriched in the subpolar region of the rod-shaped cell. Here, we report genome-wide transposon sequencing to discover the controllers of membrane compartmentalization in Mycobacterium smegmatis. The putative gene cfa showed the most significant effect on recovery from membrane compartment disruption by dibucaine. Enzymatic analysis of Cfa and lipidomic analysis of a cfa deletion mutant (Δcfa) demonstrated that Cfa is an essential methyltransferase for the synthesis of major membrane phospholipids containing a C19:0 monomethyl-branched stearic acid, also known as tuberculostearic acid (TBSA). TBSA has been intensively studied due to its abundant and genus-specific production in mycobacteria, but its biosynthetic enzymes had remained elusive. Cfa catalyzed the S-adenosyl-l-methionine-dependent methyltransferase reaction using oleic acid-containing lipid as a substrate, and Δcfa accumulated C18:1 oleic acid, suggesting that Cfa commits oleic acid to TBSA biosynthesis, likely contributing directly to lateral membrane partitioning. Consistent with this model, Δcfa displayed delayed restoration of subpolar IMD and delayed outgrowth after bacteriostatic dibucaine treatment. These results reveal the physiological significance of TBSA in controlling lateral membrane partitioning in mycobacteria. IMPORTANCE As its common name implies, tuberculostearic acid is an abundant and genus-specific branched-chain fatty acid in mycobacterial membranes. This fatty acid, 10-methyl octadecanoic acid, has been an intense focus of research, particularly as a diagnostic marker for tuberculosis. It was discovered in 1934, and yet the enzymes that mediate the biosynthesis of this fatty acid and the functions of this unusual fatty acid in cells have remained elusive. Through a genome-wide transposon sequencing screen, enzyme assay, and global lipidomic analysis, we show that Cfa is the long-sought enzyme that is specifically involved in the first step of generating tuberculostearic acid. By characterizing a cfa deletion mutant, we further demonstrate that tuberculostearic acid actively regulates lateral membrane heterogeneity in mycobacteria. These findings indicate the role of branched fatty acids in controlling the functions of the plasma membrane, a critical barrier for the pathogen to survive in its human host.
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Affiliation(s)
- Malavika Prithviraj
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
| | - Takehiro Kado
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
| | - Jacob A. Mayfield
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - David C. Young
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Annie D. Huang
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Daisuke Motooka
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Shota Nakamura
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - M. Sloan Siegrist
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts, USA
| | - D. Branch Moody
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Yasu S. Morita
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts, USA
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3
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Bedard M, van der Niet S, Bernard EM, Babunovic G, Cheng TY, Aylan B, Grootemaat AE, Raman S, Botella L, Ishikawa E, O'Sullivan MP, O'Leary S, Mayfield JA, Buter J, Minnaard AJ, Fortune SM, Murphy LO, Ory DS, Keane J, Yamasaki S, Gutierrez MG, van der Wel N, Moody DB. A terpene nucleoside from M. tuberculosis induces lysosomal lipid storage in foamy macrophages. J Clin Invest 2023; 133:161944. [PMID: 36757797 PMCID: PMC10014106 DOI: 10.1172/jci161944] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 02/03/2023] [Indexed: 02/10/2023] Open
Abstract
Induction of lipid-laden foamy macrophages is a cellular hallmark of tuberculosis (TB) disease, which involves the transformation of infected phagolysosomes from a site of killing into a nutrient-rich replicative niche. Here, we show that a terpenyl nucleoside shed from Mycobacterium tuberculosis, 1-tuberculosinyladenosine (1-TbAd), caused lysosomal maturation arrest and autophagy blockade, leading to lipid storage in M1 macrophages. Pure 1-TbAd, or infection with terpenyl nucleoside-producing M. tuberculosis, caused intralysosomal and peribacillary lipid storage patterns that matched both the molecules and subcellular locations known in foamy macrophages. Lipidomics showed that 1-TbAd induced storage of triacylglycerides and cholesterylesters and that 1-TbAd increased M. tuberculosis growth under conditions of restricted lipid access in macrophages. Furthermore, lipidomics identified 1-TbAd-induced lipid substrates that define Gaucher's disease, Wolman's disease, and other inborn lysosomal storage diseases. These data identify genetic and molecular causes of M. tuberculosis-induced lysosomal failure, leading to successful testing of an agonist of TRPML1 calcium channels that reverses lipid storage in cells. These data establish the host-directed cellular functions of an orphan effector molecule that promotes survival in macrophages, providing both an upstream cause and detailed picture of lysosome failure in foamy macrophages.
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Affiliation(s)
- Melissa Bedard
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Sanne van der Niet
- Electron Microscopy Centre Amsterdam, Amsterdam University Medical Centre, Amsterdam, Netherlands
| | - Elliott M Bernard
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Gregory Babunovic
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.,Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Tan-Yun Cheng
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Beren Aylan
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Anita E Grootemaat
- Electron Microscopy Centre Amsterdam, Amsterdam University Medical Centre, Amsterdam, Netherlands
| | - Sahadevan Raman
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Laure Botella
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Eri Ishikawa
- Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Mary P O'Sullivan
- Department of Clinical Medicine, Trinity Translational Medicine Institute, St. James's Hospital, Trinity College, Dublin, Ireland
| | - Seónadh O'Leary
- Department of Clinical Medicine, Trinity Translational Medicine Institute, St. James's Hospital, Trinity College, Dublin, Ireland
| | - Jacob A Mayfield
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Jeffrey Buter
- Department of Chemical Biology, Stratingh Institute for Chemistry, Groningen, Netherlands
| | - Adriaan J Minnaard
- Department of Chemical Biology, Stratingh Institute for Chemistry, Groningen, Netherlands
| | - Sarah M Fortune
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | | | - Daniel S Ory
- Casma Therapeutics, Cambridge, Massachusetts, USA
| | - Joseph Keane
- Department of Clinical Medicine, Trinity Translational Medicine Institute, St. James's Hospital, Trinity College, Dublin, Ireland
| | - Sho Yamasaki
- Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Maximiliano G Gutierrez
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Nicole van der Wel
- Electron Microscopy Centre Amsterdam, Amsterdam University Medical Centre, Amsterdam, Netherlands
| | - D Branch Moody
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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4
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Sullivan MR, McGowen K, Liu Q, Akusobi C, Young DC, Mayfield JA, Raman S, Wolf ID, Moody DB, Aldrich CC, Muir A, Rubin EJ. Biotin-dependent cell envelope remodelling is required for Mycobacterium abscessus survival in lung infection. Nat Microbiol 2023; 8:481-497. [PMID: 36658396 PMCID: PMC9992005 DOI: 10.1038/s41564-022-01307-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 07/20/2022] [Accepted: 12/14/2022] [Indexed: 01/21/2023]
Abstract
Mycobacterium abscessus is an emerging pathogen causing lung infection predominantly in patients with underlying structural abnormalities or lung disease and is resistant to most frontline antibiotics. As the pathogenic mechanisms of M. abscessus in the context of the lung are not well-understood, we developed an infection model using air-liquid interface culture and performed a transposon mutagenesis and sequencing screen to identify genes differentially required for bacterial survival in the lung. Biotin cofactor synthesis was required for M. abscessus growth due to increased intracellular biotin demand, while pharmacological inhibition of biotin synthesis prevented bacterial proliferation. Biotin was required for fatty acid remodelling, which increased cell envelope fluidity and promoted M. abscessus survival in the alkaline lung environment. Together, these results indicate that biotin-dependent fatty acid remodelling plays a critical role in pathogenic adaptation to the lung niche, suggesting that biotin synthesis and fatty acid metabolism might provide therapeutic targets for treatment of M. abscessus infection.
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Affiliation(s)
- Mark R Sullivan
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Kerry McGowen
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Qiang Liu
- Department of Medicinal Chemistry, University of Minnesota College of Pharmacy, Minneapolis, MN, USA
| | - Chidiebere Akusobi
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - David C Young
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jacob A Mayfield
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Sahadevan Raman
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ian D Wolf
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - D Branch Moody
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Courtney C Aldrich
- Department of Medicinal Chemistry, University of Minnesota College of Pharmacy, Minneapolis, MN, USA
| | - Alexander Muir
- Ben May Department for Cancer Research, University of Chicago, Chicago, IL, USA
| | - Eric J Rubin
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
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5
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Nicolai S, Wegrecki M, Cheng TY, Bourgeois EA, Cotton RN, Mayfield JA, Monnot GC, Le Nours J, Van Rhijn I, Rossjohn J, Moody DB, de Jong A. Human T cell response to CD1a and contact dermatitis allergens in botanical extracts and commercial skin care products. Sci Immunol 2020; 5:5/43/eaax5430. [PMID: 31901073 DOI: 10.1126/sciimmunol.aax5430] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 12/05/2019] [Indexed: 12/13/2022]
Abstract
During industrialization, humans have been exposed to increasing numbers of foreign chemicals. Failure of the immune system to tolerate drugs, cosmetics, and other skin products causes allergic contact dermatitis, a T cell-mediated disease with rising prevalence. Models of αβ T cell response emphasize T cell receptor (TCR) contact with peptide-MHC complexes, but this model cannot readily explain activation by most contact dermatitis allergens, which are nonpeptidic molecules. We tested whether CD1a, an abundant MHC I-like protein in human skin, mediates contact allergen recognition. Using CD1a-autoreactive human αβ T cell clones to screen clinically important allergens present in skin patch testing kits, we identified responses to balsam of Peru, a tree oil widely used in cosmetics and toothpaste. Additional purification identified benzyl benzoate and benzyl cinnamate as antigenic compounds within balsam of Peru. Screening of structurally related compounds revealed additional stimulants of CD1a-restricted T cells, including farnesol and coenzyme Q2. Certain general chemical features controlled response: small size, extreme hydrophobicity, and chemical constraint from rings and unsaturations. Unlike lipid antigens that protrude to form epitopes and contact TCRs, the small size of farnesol allows sequestration deeply within CD1a, where it displaces self-lipids and unmasks the CD1a surface. These studies identify molecular connections between CD1a and hypersensitivity to consumer products, defining a mechanism that could plausibly explain the many known T cell responses to oily substances.
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Affiliation(s)
- Sarah Nicolai
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Marcin Wegrecki
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Tan-Yun Cheng
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Elvire A Bourgeois
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Rachel N Cotton
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jacob A Mayfield
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Gwennaëlle C Monnot
- Columbia University Vagelos College of Physicians and Surgeons, Department of Dermatology, New York, NY 10032, USA
| | - Jérôme Le Nours
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Ildiko Van Rhijn
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jamie Rossjohn
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia.,Institute of Infection and Immunity, Cardiff University, School of Medicine, Heath Park, Cardiff CF14 4XN, UK
| | - D Branch Moody
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Annemieke de Jong
- Columbia University Vagelos College of Physicians and Surgeons, Department of Dermatology, New York, NY 10032, USA.
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6
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Reinink P, Buter J, Mishra VK, Ishikawa E, Cheng TY, Willemsen PTJ, Porwollik S, Brennan PJ, Heinz E, Mayfield JA, Dougan G, van Els CA, Cerundolo V, Napolitani G, Yamasaki S, Minnaard AJ, McClelland M, Moody DB, Van Rhijn I. Discovery of Salmonella trehalose phospholipids reveals functional convergence with mycobacteria. J Exp Med 2019; 216:757-771. [PMID: 30804000 PMCID: PMC6446866 DOI: 10.1084/jem.20181812] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 12/08/2018] [Accepted: 02/01/2019] [Indexed: 01/11/2023] Open
Abstract
Salmonella species are among the world's most prevalent pathogens. Because the cell wall interfaces with the host, we designed a lipidomics approach to reveal pathogen-specific cell wall compounds. Among the molecules differentially expressed between Salmonella Paratyphi and S. Typhi, we focused on lipids that are enriched in S. Typhi, because it causes typhoid fever. We discovered a previously unknown family of trehalose phospholipids, 6,6'-diphosphatidyltrehalose (diPT) and 6-phosphatidyltrehalose (PT). Cardiolipin synthase B (ClsB) is essential for PT and diPT but not for cardiolipin biosynthesis. Chemotyping outperformed clsB homology analysis in evaluating synthesis of diPT. DiPT is restricted to a subset of Gram-negative bacteria: large amounts are produced by S. Typhi, lower amounts by other pathogens, and variable amounts by Escherichia coli strains. DiPT activates Mincle, a macrophage activating receptor that also recognizes mycobacterial cord factor (6,6'-trehalose dimycolate). Thus, Gram-negative bacteria show convergent function with mycobacteria. Overall, we discovered a previously unknown immunostimulant that is selectively expressed among medically important bacterial species.
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Affiliation(s)
- Peter Reinink
- Department of Infectious Diseases and Immunology, School of Veterinary Medicine, Utrecht University, Utrecht, Netherlands.,Department of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Boston, MA
| | - Jeffrey Buter
- Department of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Boston, MA
| | - Vivek K Mishra
- Stratingh Institute for Chemistry, University of Groningen, Groningen, Netherlands
| | - Eri Ishikawa
- Department of Molecular Immunology, Immunology Frontier Research Center, Osaka University, Osaka, Japan.,Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Tan-Yun Cheng
- Department of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Boston, MA
| | - Peter T J Willemsen
- Wageningen Bioveterinary Research, Department of Infection Biology, Lelystad, Netherlands
| | - Steffen Porwollik
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, CA
| | - Patrick J Brennan
- Department of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Boston, MA
| | - Eva Heinz
- Wellcome Trust Sanger Institute, Hinxton, UK
| | - Jacob A Mayfield
- Department of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Boston, MA
| | | | - Cécile A van Els
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, Netherlands
| | - Vincenzo Cerundolo
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Giorgio Napolitani
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Sho Yamasaki
- Department of Molecular Immunology, Immunology Frontier Research Center, Osaka University, Osaka, Japan.,Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Adriaan J Minnaard
- Stratingh Institute for Chemistry, University of Groningen, Groningen, Netherlands
| | - Michael McClelland
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, CA
| | - D Branch Moody
- Department of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Boston, MA
| | - Ildiko Van Rhijn
- Department of Infectious Diseases and Immunology, School of Veterinary Medicine, Utrecht University, Utrecht, Netherlands .,Department of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Boston, MA
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7
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Puffal J, Mayfield JA, Moody DB, Morita YS. Demethylmenaquinone Methyl Transferase Is a Membrane Domain-Associated Protein Essential for Menaquinone Homeostasis in Mycobacterium smegmatis. Front Microbiol 2018; 9:3145. [PMID: 30619211 PMCID: PMC6305584 DOI: 10.3389/fmicb.2018.03145] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 12/04/2018] [Indexed: 12/20/2022] Open
Abstract
The intracellular membrane domain (IMD) in mycobacteria is a spatially distinct region of the plasma membrane with diverse functions. Previous comparative proteomic analysis of the IMD suggested that menaquinone biosynthetic enzymes are associated with this domain. In the present study, we determined the subcellular site of these enzymes using sucrose density gradient fractionation. We found that the last two enzymes, the methyltransferase MenG, and the reductase MenJ, are associated with the IMD in Mycobacterium smegmatis. MenA, the prenyltransferase that mediates the first membrane-associated step of the menaquinone biosynthesis, is associated with the conventional plasma membrane. For MenG, we additionally showed the polar enrichment of the fluorescent protein fusion colocalizing with an IMD marker protein in situ. To start dissecting the roles of IMD-associated enzymes, we further tested the physiological significance of MenG. The deletion of menG at the endogenous genomic loci was possible only when an extra copy of the gene was present, indicating that it is an essential gene in M. smegmatis. Using a tetracycline-inducible switch, we achieved gradual and partial depletion of MenG over three consecutive 24 h sub-cultures. This partial MenG depletion resulted in progressive slowing of growth, which corroborated the observation that menG is an essential gene. Upon MenG depletion, there was a significant accumulation of MenG substrate, demethylmenaquinone, even though the cellular level of menaquinone, the reaction product, was unaffected. Furthermore, the growth retardation was coincided with a lower oxygen consumption rate and ATP accumulation. These results imply a previously unappreciated role of MenG in regulating menaquinone homeostasis within the complex spatial organization of mycobacterial plasma membrane.
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Affiliation(s)
- Julia Puffal
- Department of Microbiology, University of Massachusetts, Amherst, MA, United States
| | - Jacob A. Mayfield
- Division of Rheumatology, Immunology and Allergy, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
| | - D. Branch Moody
- Division of Rheumatology, Immunology and Allergy, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
| | - Yasu S. Morita
- Department of Microbiology, University of Massachusetts, Amherst, MA, United States
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8
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Rahlwes KC, Ha SA, Motooka D, Mayfield JA, Baumoel LR, Strickland JN, Torres-Ocampo AP, Nakamura S, Morita YS. The cell envelope-associated phospholipid-binding protein LmeA is required for mannan polymerization in mycobacteria. J Biol Chem 2017; 292:17407-17417. [PMID: 28855252 DOI: 10.1074/jbc.m117.804377] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 08/28/2017] [Indexed: 11/06/2022] Open
Abstract
The integrity of the distinguishing, multilaminate cell envelope surrounding mycobacteria is critical to their survival and pathogenesis. The prevalence of phosphatidylinositol mannosides in the cell envelope suggests an important role in the mycobacterial life cycle. Indeed, deletion of the pimE gene (ΔpimE) encoding the first committed step in phosphatidylinositol hexamannoside biosynthesis in Mycobacterium smegmatis results in the formation of smaller colonies than wild-type colonies on Middlebrook 7H10 agar. To further investigate potential contributors to cell-envelope mannan biosynthesis while taking advantage of this colony morphology defect, we isolated spontaneous suppressor mutants of ΔpimE that reverted to wild-type colony size. Of 22 suppressor mutants, 6 accumulated significantly shorter lipomannan or lipoarabinomannan. Genome sequencing of these mutants revealed mutations in genes involved in the lipomannan/lipoarabinomannan biosynthesis, such as those encoding the arabinosyltransferase EmbC and the mannosyltransferase MptA. Furthermore, we identified three mutants carrying a mutation in a previously uncharacterized gene, MSMEG_5785, that we designated lmeA Complementation of these suppressor mutants with lmeA restored the original ΔpimE phenotypes and deletion of lmeA in wild-type M. smegmatis resulted in smaller lipomannan, as observed in the suppressor mutants. LmeA carries a predicted N-terminal signal peptide, and density gradient fractionation and detergent extractability experiments indicated that LmeA localizes to the cell envelope. Using a lipid ELISA, we found that LmeA binds to plasma membrane phospholipids, such as phosphatidylethanolamine and phosphatidylinositol. LmeA is widespread throughout the Corynebacteriales; therefore, we concluded that LmeA is an evolutionarily conserved cell-envelope protein critical for controlling the mannan chain length of lipomannan/lipoarabinomannan.
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Affiliation(s)
- Kathryn C Rahlwes
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Stephanie A Ha
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Daisuke Motooka
- the Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Jacob A Mayfield
- the Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02445
| | - Lisa R Baumoel
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Justin N Strickland
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Ana P Torres-Ocampo
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Shota Nakamura
- the Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Yasu S Morita
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003,
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9
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Hwang LH, Mayfield JA, Rine J, Sil A. Histoplasma requires SID1, a member of an iron-regulated siderophore gene cluster, for host colonization. PLoS Pathog 2008; 4:e1000044. [PMID: 18404210 PMCID: PMC2275787 DOI: 10.1371/journal.ppat.1000044] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [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] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Accepted: 03/13/2008] [Indexed: 11/26/2022] Open
Abstract
The macrophage is the primary host cell for the fungal pathogen Histoplasma capsulatum during mammalian infections, yet little is known about fungal genes required for intracellular replication in the host. Since the ability to scavenge iron from the host is important for the virulence of most pathogens, we investigated the role of iron acquisition in H. capsulatum pathogenesis. H. capsulatum acquires iron through the action of ferric reductases and the production of siderophores, but the genes responsible for these activities and their role in virulence have not been determined. We identified a discrete set of co-regulated genes whose transcription is induced under low iron conditions. These genes all appeared to be involved in the synthesis, secretion, and utilization of siderophores. Surprisingly, the majority of these transcriptionally co-regulated genes were found clustered adjacent to each other in the genome of the three sequenced strains of H. capsulatum, suggesting that their proximity might foster coordinate gene regulation. Additionally, we identified a consensus sequence in the promoters of all of these genes that may contribute to iron-regulated gene expression. The gene set included L-ornithine monooxygenase (SID1), the enzyme that catalyzes the first committed step in siderophore production in other fungi. Disruption of SID1 by allelic replacement resulted in poor growth under low iron conditions, as well as a loss of siderophore production. Strains deficient in SID1 showed a significant growth defect in murine bone-marrow-derived macrophages and attenuation in the mouse model of infection. These data indicated that H. capsulatum utilizes siderophores in addition to other iron acquisition mechanisms for optimal growth during infection. Fungal infections are a growing public health threat, particularly for immunocompromised individuals such as people with AIDS, organ transplant recipients, and cancer patients. Present antifungal therapies are often highly toxic and resistance to these therapies continues to rise. Histoplasma capsulatum is a pathogenic fungus that infects humans, causing pulmonary and systemic disease. It is the most common cause of fungal respiratory infection in the world, and is endemic to the Mississippi and Ohio River valleys of the United States. H. capsulatum produces small molecules, called siderophores, to acquire iron, an essential nutrient. We have identified genes that are involved in the synthesis of siderophores in this fungus and have found that siderophore production in H. capsulatum is important for its virulence. Since siderophore production is confined to microbes and plays no role in human biology, it is an excellent target for rational drug design.
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Affiliation(s)
- Lena H. Hwang
- Department of Microbiology and Immunology, University of California, San Francisco, California, United States of America
| | - Jacob A. Mayfield
- Department of Molecular and Cell Biology, California Institute of Quantitative Biosciences, University of California, Berkeley, California, United States of America
| | - Jasper Rine
- Department of Molecular and Cell Biology, California Institute of Quantitative Biosciences, University of California, Berkeley, California, United States of America
| | - Anita Sil
- Department of Microbiology and Immunology, University of California, San Francisco, California, United States of America
- * E-mail:
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10
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Abstract
The pathogenic fungus Histoplasma capsulatum causes disease ranging from mild to fatal in healthy and immunocompromised humans. Infection rates reach 80% in endemic areas, including the Midwestern United States. We used inbred mice to identify a 300-fold difference in fungal burden. A/J mice showed lower fungal burden and morbidity than C57BL/6J mice, a reversal of the trend observed for many bacterial pathogens. We mapped the differences in fungal burden to discrete locations on chromosomes 1, 6, 15 and 17 with high significance. Substitution of a single resistant chromosome 17 onto the susceptible background was sufficient to lower fungal burden. These loci will allow dissection of the fungal-specific immune program.
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Affiliation(s)
- J A Mayfield
- Department of Molecular and Cell Biology, The University of California Berkeley, Berkeley, CA 94720-3202, USA
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11
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Ramus RM, Sheffield JS, Mayfield JA, Wendel GD. A randomized trial that compared oral cefixime and intramuscular ceftriaxone for the treatment of gonorrhea in pregnancy. Am J Obstet Gynecol 2001; 185:629-32. [PMID: 11568790 DOI: 10.1067/mob.2001.117662] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The purpose of this study was to evaluate prospectively the Centers for Disease Control recommendations for the treatment of gonococcal infection in pregnancy. STUDY DESIGN One hundred sixty-one women who were referred with probable endocervical gonorrhea underwent pretreatment endocervical, anal, and oral cultures for Neisseria gonorrhoeae. The women were randomly assigned to receive ceftriaxone 125 mg intramuscularly or cefixime 400 mg orally. Treatment was open and in a 1:1 distribution. There were 95 evaluable patients. The tests of cure cultures were performed 4 to 10 days after treatment. RESULTS Eighty-six women (91%) had endocervical infection; 39 women (41%) had anal infection, and 11 women (12%) had pharyngeal infection. Fifty of 95 women (53%) had concomitant endocervical chlamydial infection. The overall efficacy was 91 of 95 subjects (95.8%; 95% CI, 89.6%-98.8%). Ceftriaxone was effective in 41 of 43 cases (95%; 95% CI, 84.2%-99.4%), and cefixime was effective in 50 of 52 cases (96%; 95% CI, 86.8%-99.5%). No significant difference was noted in the overall efficacy or by site of infection. Three of the 4 women who experienced treatment failures admitted to unprotected intercourse before their test of cure culture. CONCLUSION Both intramuscular ceftriaxone 125 mg and oral cefixime 400 mg appear to be effective for the treatment of gonococcal infection in pregnancy.
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Affiliation(s)
- R M Ramus
- Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas 75390-9032, USA.
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12
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Abstract
The pollen extracellular matrix contains proteins mediating species specificity and components needed for efficient pollination. We identified all proteins >10 kilodaltons in the Arabidopsis pollen coating and showed that most of the corresponding genes reside in two genomic clusters. One cluster encodes six lipases, whereas the other contains six lipid-binding oleosin genes, including GRP17, a gene that promotes efficient pollination. Individual oleosins exhibit extensive divergence between ecotypes, but the entire cluster remains intact. Analysis of the syntenic region in Brassica oleracea revealed even greater divergence, but a similar clustering of the genes. Such allelic flexibility may promote speciation in plants.
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Affiliation(s)
- J A Mayfield
- Department of Molecular Genetics and Cell Biology, Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
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13
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Mayfield JA, Reiber GE, Maynard C, Czerniecki JM, Caps MT, Sangeorzan BJ. Survival following lower-limb amputation in a veteran population. J Rehabil Res Dev 2001; 38:341-5. [PMID: 11440266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
GOAL We sought to describe the common demographic and comorbid conditions that affect survival following nontraumatic amputation. METHODS Veterans Administration hospital discharge records for 1992 were linked with death records. The most proximal level during the first hospitalization in 1992 was used for analysis. Demographic information (age, race) and comorbid diagnosis (cardiovascular, cerebrovascular, and renal disease) were used for Kaplan-Meier curves to describe survival following amputation. MAIN OUTCOME MEASURE Death. RESULTS Mortality risk increased with advanced age, more proximal amputation level, and renal and cardiovascular disease, and decreased for African Americans. No increased risk for persons with diabetes was noted in the first year following amputation but the risk increased thereafter. A higher risk of mortality in the first year was noted for renal disease, cardiovascular disease, and proximal amputation level. CONCLUSION Survival following lower-limb amputation is impaired by advancing age, cardiovascular and renal disease, and proximal amputation level. Also, a small survival advantage is seen for African Americans and those with diabetes.
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Affiliation(s)
- J A Mayfield
- Center of Excellence in Amputation, Prosthetics, and Limb Loss Prevention, Rehabilitation Research and Development, Puget Sound Health Care System, Seattle, WA, USA
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14
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Mayfield JA, Caps MT, Reiber GE, Maynard C, Czerniecki JM, Sangeorzan BJ. Trends in peripheral vascular procedures in the Veterans Health Administration, 1989-1998. J Rehabil Res Dev 2001; 38:347-56. [PMID: 11440267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
OBJECTIVE To assess trends in peripheral vascular procedures performed in Veterans Health Administration (VHA) facilities. METHODS All discharges with peripheral vascular procedures recorded for 1989-1998 were analyzed. The VHA user population was used to calculate age-specific rates. Trends were evaluated using frequency tables and Poisson regression. RESULTS The VHA had 55,916 discharges with peripheral vascular procedures performed almost exclusively in men. Indications included peripheral vascular disease (53.7%), gangrene (19.3%), surgical complications (13.3%), and ulcers and infection (9.6%). The VHA age-specific rates were higher than US population rates for persons 45 to 64 years, similar for those 65 to 74 years, and lower for those 75 years and older. The age-specific rates declined slightly over the 10 years of observation, with the greatest decline noted in men age 45 to 65. CONCLUSION The VHA provides almost 8% of all US peripheral vascular procedures in males. The VHA age-specific rates differ from the US rates with a shift to younger patients. The rates decreased for all age groups between 1989-1998.
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Affiliation(s)
- J A Mayfield
- Center of Excellence in Prosthetic Engineering and Limb Loss Prevention, Rehabilitation Research and Development, Puget Sound Health Care System, Seattle, WA, USA
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Abstract
OBJECTIVE To describe geographic variation in rates of lower-limb major amputation in Medicare patients with and without diabetes. RESEARCH DESIGN AND METHODS This cross-sectional population-based study used national fee-for-service Medicare claims from 1996 through 1997. The unit of analysis was 306 hospital referral regions (HRRs) representing health care markets for their respective tertiary medical centers. Numerators were calculated using nontraumatic major amputations and the diabetes code (250.x) for individuals with diabetes. Denominators for individuals with diabetes were created by multiplying the regional prevalence of diabetes (as determined using a 5% sample of Medicare Part B data identifying at least two visits with a diabetes code for 1995-1996) by the regional Medicare population. Denominators for individuals without diabetes were the remaining Medicare beneficiaries. Rates of major amputations were adjusted for age, sex, and race. RESULTS Rates of major amputations per year were 3.83 per 1,000 (95% CI 3.60-4.06) individuals with diabetes compared with 0.38 per 1,000 (95% C1 0.35-0.41) individuals without diabetes. Marked geographic variation was observed for individuals with and without diabetes; however, patterns were distinct between the two populations. Rates were high in the Southern and Atlantic states for individuals without diabetes. In contrast, rates for individuals with diabetes were widely varied. Variation across HRRs for individuals with diabetes was 8.6-fold compared with 6.7-fold in individuals without diabetes for major amputations. CONCLUSIONS Diabetes-related amputation rates exhibit high regional variation, even after age, sex, and race adjustment. Future work should be directed to exploring sources of this variation.
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Affiliation(s)
- J S Wrobel
- Veterans Affairs Medical and Regional Office Center, White River Junction, Vermont 05009, USA.
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16
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Mayfield JA, Sugarman JR. The use of the Semmes-Weinstein monofilament and other threshold tests for preventing foot ulceration and amputation in persons with diabetes. J Fam Pract 2000; 49:S17-S29. [PMID: 11093555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
OBJECTIVE To evaluate the evidence supporting the Semmes-Weinstein monofilament (SWM) and other threshold testing in preventing ulcers and amputation. SEARCH STRATEGY We searched the MEDLINE database using the Medical Subject Headings ("diabetic foot" or "diabetes mellitus" and ["foot ulcer" or "foot diseases"]) and ("sensory threshold" or "touch" or "vibration" or "monofilament [text word]" or "two point discrimination [text word]") restricted to studies with human subjects and published in the English language between 1985 and 2000. DATA ABSTRACTION The studies were abstracted by one author (J.M.) and confirmed by the second author (J.S.). SELECTION CRITERIA The studies had to contain original data collection and SWM or another threshold assessment method. DATA COLLECTION/ANALYSIS All articles were abstracted for study design, testing method, population, and results. MAIN RESULTS We identified 6 prospective studies using SWMs and 4 with vibration perception thresholds (VPTs), including 1 randomized controlled trial. The increased risk of ulceration ranged from an odds ratio (OR) of 2.2 to 9.99, and the risk of amputation was a relative risk of 2.9 using the SWM and an OR of 4.38 to 7.99 for VPT. The randomized controlled trial of screening plus treatment for those with previous ulcers had no significant decrease in the number of ulcers or minor amputations but showed significantly fewer major amputations. CONCLUSIONS The SWM is currently the best choice for screening for clinically significant neuropathy because it is portable, inexpensive, painless, easy to administer, acceptable to patients, and provides good predictive ability for the risk of ulceration and amputation. Once the patient without protective sensation has been identified, management with protective footwear and patient education to prevent damage should be instituted but compliance is often difficult to implement.
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Affiliation(s)
- J A Mayfield
- School of Public Health and Community Medicine, University of Washington, Veterans Affairs Puget Sound Health Care System, Seattle, USA.
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17
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Fiebig A, Mayfield JA, Miley NL, Chau S, Fischer RL, Preuss D. Alterations in CER6, a gene identical to CUT1, differentially affect long-chain lipid content on the surface of pollen and stems. Plant Cell 2000; 12:2001-8. [PMID: 11041893 PMCID: PMC149136 DOI: 10.1105/tpc.12.10.2001] [Citation(s) in RCA: 240] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2000] [Accepted: 08/21/2000] [Indexed: 05/17/2023]
Abstract
Very long chain lipids contribute to the hydrophobic cuticle on the surface of all land plants and are an essential component of the extracellular pollen coat in the Brassicaceae. Mutations in Arabidopsis CER genes eliminate very long chain lipids from the cuticle surface and, in some cases, from the pollen coat. In Arabidopsis, the loss of pollen coat lipids can disrupt interactions with the stigma, inhibiting pollen hydration and causing sterility. We have positionally cloned CER6 and demonstrate that a wild-type copy complements the cer6-2 defect. In addition, we have identified a fertile, intragenic suppressor, cer6-2R, that partially restores pollen coat lipids but does not rescue the stem wax defect, suggesting an intriguing difference in the requirements for CER6 activity on stems and the pollen coat. Importantly, analysis of this suppressor demonstrates that low amounts of very long chain lipids are sufficient for pollen hydration and germination. The predicted CER6 amino acid sequence resembles that of fatty acid-condensing enzymes, consistent with its role in the production of epicuticular and pollen coat lipids >28 carbons long. DNA sequence analysis revealed the nature of the cer6-1, cer6-2, and cer6-2R mutations, and segregation analysis showed that CER6 is identical to CUT1, a cDNA previously mapped to a different chromosome arm. Instead, we have determined that a new gene, CER60, with a high degree of nucleotide and amino acid similarity to CER6, resides at the original CUT1 locus.
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Affiliation(s)
- A Fiebig
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637, USA
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18
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Mayfield JA, Reiber GE, Nelson RG, Greene T. Do foot examinations reduce the risk of diabetic amputation? J Fam Pract 2000; 49:499-504. [PMID: 10923547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
BACKGROUND Foot examinations are widely recommended as a means to reduce amputation risk, but no investigators have studied their independent effect on this outcome. METHODS We conducted a population-based case-control study of primary care provided to Pima Indians from the Gila River Indian Community. Sixty-one Pima Indians with type 2 diabetes and a first lower-extremity amputation between January 1, 1985, and December 31, 1992, were compared with 183 people who had no amputation by December 31, 1992. The type of foot examination conducted, comorbid conditions, and foot risk factors present in the 36 months before the pivotal event were abstracted from medical records. All ulcer care was excluded. The independent effect of foot examinations on the risk of amputation was assessed by logistic regression. RESULTS During the 36 study months, 1857 foot examinations were performed on 244 subjects. The median number of preventive foot examinations was 7 for case patients and 3 for control patients. After controlling for differences in comorbid conditions and foot risk conditions, the risk of amputation for persons with 1 or more foot examinations was an odds ratio (OR) of 0.55 (95% confidence interval [CI], 0.2-1.7; P=.31). The risk of amputation associated with written comments of nonadherence with therapeutic foot care recommendations or diabetic medication was an OR of 1.9 (95% CI, 0.9-4.3; P=.10). CONCLUSIONS Our study failed to demonstrate that foot examinations decrease the risk of amputation in Pima Indians with type 2 diabetes. However, foot examinations detect high-risk conditions for which specific interventions have been shown to be effective in reducing amputation risk.
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Affiliation(s)
- J A Mayfield
- Bowen Research Center, Department of Family Medicine, Indiana University, Indianapolis, USA.
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19
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Affiliation(s)
- J A Mayfield
- Department of Molecular Genetics, The University of Chicago, Chicago, Illinois 60637, USA
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Mayfield JA, Reiber GE, Maynard C, Czerniecki JM, Caps MT, Sangeorzan BJ. Trends in lower limb amputation in the Veterans Health Administration, 1989-1998. J Rehabil Res Dev 2000; 37:23-30. [PMID: 10847569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
OBJECTIVE To assess trends in lower limb amputation performed in Veterans Health Administration (VHA) facilities. METHODS All lower limb amputations recorded in the Patient Treatment File for 1989-1998 were analyzed using the hospital discharge as the unit of analysis. Age-specific rates were calculated using the VHA user-population as the denominator. Frequency tables and linear, logistic, and Poisson regression were used respectively to assess trends in amputation numbers, reoperation rates, and age-specific amputation rates. RESULTS Between 1989-1998, there were 60,324 discharges with amputation in VHA facilities. Over 99.9% of these were in men and constitute 10 percent of all US male amputations. The major indications were diabetes (62.9%) and peripheral vascular disease alone (23.6%). The age-specific rates of major amputation in the VHA are higher than US rates of major amputation. VHA rates of major and minor amputation declined an average of 5% each year, while the number of diabetes-associated amputations remained the same. CONCLUSION The number and age-specific rates of amputations decreased over 10 years despite an increase in the number of veterans using VHA care.
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Affiliation(s)
- J A Mayfield
- Center of Excellence in Amputation, Prosthetics, and Limb Loss Prevention, Rehabilitation Research and Development, Puget Sound Health Care System, Seattle, WA 98108, USA
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Abstract
OBJECTIVE To determine the rates and demographic determinants of work disability, hours worked per week, work-loss days, and wages in individuals with diabetes. RESEARCH DESIGN AND METHODS A probit regression analysis was performed on a cross-sectional population-based survey of U.S. noninstitutionalized civilian population (National Medical Expenditures Survey--2, 1987). The sample was restricted to individuals aged > or = 25 years. A total of 1,502 individuals reported having diabetes, and 20,405 did not. Information on workforce participation and income were collected quarterly. Work disability was defined as a self-report of having been unable to work because of illness or disability for > or = 2 quarters in 1987. RESULTS Work disability was reported by 25.6% of individuals with diabetes, compared with 7.8% of those without diabetes. Work disability rates were higher for older people, females, and African-Americans, and lower for Hispanics and for individuals with greater non-wage income. Individuals with diabetes engaged in the workforce had more work-loss days than did nondiabetic individuals, but had similar hourly wages. Predicted mean earnings were significantly lower for individuals with diabetes at all ages, resulting in $4.7 million loss in earnings in 1987 due to work disability. CONCLUSIONS Work disability is significantly higher for individuals with diabetes than for those without diabetes at all ages, and results in a significant decrease in earnings. A disproportionate burden of work disability is borne by older individuals and women with diabetes. Better information on the determinants of work disability in individuals with diabetes is needed.
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Affiliation(s)
- J A Mayfield
- Department of Family Practice, Bowen Research Center, Indiana University, Indianapolis, USA
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Abstract
A number of effective, low-cost strategies are available to identify and treat the person at risk for diabetic foot ulcers and lower-extremity amputation. These strategies must be more widely adopted by all diabetic care providers to maintain the integrity and function of the lower limb, and thus improve the quality of life for people with diabetes.
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Affiliation(s)
- J A Mayfield
- Bowen Research Center, Department of Family Medicine, Indiana University, Indianapolis 46202, USA.
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Abstract
OBJECTIVE To quantify the contribution of various risk factors to the risk of amputation in diabetic patients and to develop a foot risk scoring system based on clinical data. RESEARCH DESIGN AND METHODS A population case-control study was undertaken. Eligible subjects were 1) 25-85 years of age, 2) diabetic, 3) 50% or more Pima or Tohono O'odham Indian, 4) lived in the Gila River Indian Community, and 5) had had at least one National Institutes of Health research examination. Case patients had had an incident lower extremity amputation between 1983 and 1992; control subjects had no amputation by 1992. Medical records were reviewed to determine risk conditions and health status before the pivotal event that led to the amputation. RESULTS Sixty-one people with amputations were identified and compared with 183 control subjects. Men were more likely to suffer amputation than women (odds ratio [OR] 6.5, 95% CI 2.6-15), and people with diabetic eye, renal, or cardiovascular disease were more likely to undergo amputation than those without (OR 4.6, 95% CI 1.7-12). The risk of amputation was almost equally associated with these foot risk factors: peripheral neuropathy, peripheral vascular disease, bony deformities, and a history of foot ulcers. After controlling for demographic differences and diabetes severity, the ORs for amputation with one foot risk factor was 2.1 (95% CI 1.4-3.3), with two risk factors, 4.5 (95% CI 2.9-6.9), and with three or four risk factors, 9.7 (95% CI 6.3-14.8). CONCLUSIONS Male Sex, end-organ complications of eye, heart, and kidney, and poor glucose control were associated with a higher amputation rate. Peripheral neuropathy, peripheral vascular disease, deformity, and a prior ulcer were similarly equally associated with an increased risk of lower extremity amputation.
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Affiliation(s)
- J A Mayfield
- Bowen Research Center, Indiana University, Indianapolis, USA
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Abstract
In this report, we propose new International Classification of Diseases (ICD) codes that could be incorporated into computer-based patient records or administrative data to monitor and improve diabetes care. Neither the ICD, 9th Revision, nor its imminent replacement, the ICD, 10th Revision, has specific codes for foot examinations and funduscopic examinations in the asymptomatic person, high-risk diabetic foot status, or clinically significant macular edema. Adoption of official codes for these procedures and conditions implemented in conjunction with computerized databases could be used for surveillance, program planning, and quality of care assessment. Computerized medical records could use the codes to monitor care and issue reminders to patients and providers. Payors could offer reimbursement incentives to encourage compliance with standard recommendations. These codes for care procedures could be linked to outcomes, such as amputations and blindness, to improve our understanding of the etiology of blindness and the relationship between process and outcome. The uniform adoption of these codes would facilitate comparison between health care systems, geographic regions, and nations. The diabetes community should encourage the National Center for Health Statistics to adopt new codes that could be used to monitor diabetes preventive care practices.
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Affiliation(s)
- J A Mayfield
- Department of Family Medicine, Bowen Research Center, Indiana University-Purdue University at Indianapolis, USA
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Mayfield JA, Rith-Najarian SJ, Acton KJ, Schraer CD, Stahn RM, Johnson MH, Gohdes D. Assessment of diabetes care by medical record review. The Indian Health Service model. Diabetes Care 1994; 17:918-23. [PMID: 7956644 DOI: 10.2337/diacare.17.8.918] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To evaluate the adherence to minimum standards for diabetes care in multiple primary-care facilities using a uniform system of medical record review. RESEARCH DESIGN AND METHODS In 1986, the Indian Health Service (IHS) developed diabetes care standards and an assessment process to evaluate adherence to those standards using medical record review. We review our assessment method and results for 1992. Charts were selected in a systematic random fashion from 138 participating facilities. Trained professional staff reviewed patient charts, using a uniform set of definitions. A weighted rate of adherence was constructed for each item. RESULTS Medical record reviews were conducted on 6,959 charts selected from 40,118 diabetic patients. High rates of adherence (> 70%) were noted for blood pressure and weight measurements at each visit, blood sugar determinations at each visit, annual laboratory screening tests, electrocardiogram at baseline, and adult immunizations. Lower rates of adherence (< or = 50%) were noted for annual eye, foot, and dental examinations. CONCLUSIONS IHS rates of adherence are similar to rates obtained from medical record reviews and computerized billing data, but are less than rates obtained by provider self-report. Medical record review, using uniform definitions and inexpensive software for data entry and reports, can easily be implemented in multiple primary-care settings. Uniformity of data definition and collection facilitates the aggregation of the data and comparison over time and among facilities. This medical record review system, although labor intensive, can be easily adopted in a variety of primary-care settings for quality improvement activities, program planning, and evaluation.
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Affiliation(s)
- J A Mayfield
- Department of Family Medicine, Bowen Research Center, Indiana University, Indianapolis 46202
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Rosenblatt RA, Mayfield JA, Hart LG. Neonatal mortality clusters: a new tool for classifying neonatal outcomes. J Am Board Fam Pract 1991; 4:299-306. [PMID: 1746297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND A method for assessing general hospital neonatal care performance is needed that is simple, is easy to use, and requires minimal data. METHODS All neonatal deaths in Washington State obstetric hospitals from 1980 to 1983 were assigned to 10 mutually exclusive neonatal mortality clusters, a new classification method derived from information available on the death certificate. RESULTS More than one-third (35.3 percent) of all neonatal deaths fell within one of the seven clusters considered to represent potentially preventable causes of death. The rate of possibly preventable deaths was much higher in level III hospitals than in level II or level I hospitals, a finding similar to that observed in other states using different analytic approaches. CONCLUSIONS Neonatal mortality clusters offer a less complex method of classifying neonatal deaths and assessing hospital performance than other currently used techniques.
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Affiliation(s)
- R A Rosenblatt
- Department of Family Medicine, University of Washington School of Medicine, Seattle 98195
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Salive ME, Mayfield JA, Weissman NW. Patient Outcomes Research Teams and the Agency for Health Care Policy and Research. Health Serv Res 1990; 25:697-708. [PMID: 2254084 PMCID: PMC1065656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- M E Salive
- Center for Medical Effectiveness Research, Agency for Health Care Policy and Research (AHCPR), MD
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Abstract
We investigated the relation of hospital delivery volume and nursery technology level to perinatal outcome in 226,164 White singleton births in Washington State, 1980-83. Level III facilities (neonatal intensive care unit) were defined by the state licensing commission. We defined the Level II (intermediate) and Level I (normal newborn) facilities using published criteria. Infants under 2000 gm born in Level III facilities had half the risk of perinatal death compared to those born in a Level I or II facility. No significant improvement was noted among level or volume groupings for normal birthweight infants. A loglinear regression model of hospital perinatal death rates showed that when birthweight and maternal risk were controlled, obstetrical volume added minimal explanatory power to level of nursery care.
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Affiliation(s)
- J A Mayfield
- Department of Family Medicine, Health Services and Biostatistics, University of Washington, Seattle
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Rosenblatt RA, Mayfield JA, Hart LG, Baldwin LM. Outcomes of regionalized perinatal care in Washington State. West J Med 1988; 149:98-102. [PMID: 3407173 PMCID: PMC1026272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We evaluated the extent to which the regionalization of perinatal care in Washington State has succeeded in concentrating high-risk pregnancies in technologically appropriate referral centers and in reducing differences in neonatal outcome among hospitals. Of all infants weighing less than 1,500 grams born between 1980 and 1983, nearly 68% were delivered in level III hospitals, although only 24% of all babies are born in these hospitals, indicating that the state is highly regionalized. Neonatal outcomes-as measured by standardized mortality ratios-are similar in level I, II and III hospitals and are not greatly influenced by the rural or urban location of the hospital. The most promising strategy for further reducing neonatal mortality is to decrease the number and proportion of very-low-birth-weight births.
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