Sphingolipid Metabolism in Drosophila Development

Summary

Principal Investigator: Julie D Saba
Abstract: DESCRIPTION (provided by applicant): Sphingolipids are a conserved family of lipids built upon a sphingoid base backbone. Sphingolipids serve structural membrane functions, whereas their metabolism produces signaling molecules involved in regulating mammalian development, immune function, inflammation and cellular stress responses. Studies supported by this grant have explored the role of sphingolipids in the model organism Drosophila melanogaster. These studies have resulted in the chemical characterization of Drosophila sphingoid bases and the identification of novel endogenous Drosophila sphingolipids with potent growth-inhibitory activity. Further, we have shown that Sply mutants lacking expression of Drosophila sphingosine-1-phosphate (S1P) lyase (SPL), which is responsible for the final step of sphingolipid degradation, accumulate sphingolipid intermediates and develop a progressive myopathy in the thoracic muscles needed to power flight. The Sply myopathy is corrected by reducing sphingolipid production, indicating sphingolipid intermediates play a causative role. We have observed that mutants in key membrane proteins such as dynamin and dystroglycan phenocopy the Sply myopathy. We have also conducted cell-based investigations that suggest that Sply/SPL is required for normal AKT signaling, protein translation, myoblast fusion, myoblast gene expression and control of autophagy. Many of these interactions have been corroborated in murine C2C12 cells, indicating that SPL plays a conserved role in myoblast survival, fusion and differentiation. We have also found that sphingosine kinase and S1P lyase are dynamically upregulated during murine muscle regeneration, leading to a transient peak in S1P levels in regenerating muscle. These collective observations have led us to propose our central hypothesis, which states that SPL plays a critical role in muscle biology, development and homeostasis. The specific aims of our proposal are, thus: 1) To define the role of SPL in muscle cell biology;2) To dissect the role of SPL in muscle development;and 3) To establish the role of SPL in muscle atrophy and regeneration. Our long-term goals are to exploit Drosophila to elucidate the role of sphingolipids in biology, membrane function, and tissue homeostasis and to define the relevance of these findings to human disease. Due to species-specific structural differences in sphingolipids and the lack of S1P receptors in lower eukaryotes, we do not expect the two systems to be equivalent. Thus, our goals are to compare the biochemical and molecular events associated with SPL loss in Drosophila and murine cell and animal models, with the intent of developing a comprehensive understanding of how SPL functions in the context of muscle tissue and how its function may have been modified throughout evolution. These studies should be readily achieved by our team, which has extensive experience in sphingolipid biochemistry, Drosophila genetics, and the genetics and pathology of MD. PUBLIC HEALTH RELEVANCE: The studies proposed in this application will elucidate mechanisms by which sphingolipids influence key processes involved in muscle development and regeneration, including myogenic gene expression, membrane fusion, satellite cell activation, muscle membrane structure and extracellular matrix processing. Our research plan includes studies to specifically address the translational relevance of S1P metabolism in mammalian muscle injury, atrophy and regeneration using preclinical rodent models. The information gained from this work is therefore relevant to muscle-wasting syndromes, age-related frailty, inherited muscular dystrophies and related musculoskeletal disorders arising from defects of extracellular matrix remodeling. Skeletal muscle is also a prime target organ for gene therapy, since engineered myoblasts can be made to fuse with mature muscle, generating a stable hybrid organ within the adult. Thus, our studies of myoblast fusion may be relevant to an array of disorders potentially treatable by genetic therapy. Our proposed studies will also characterize how sphingolipids interact with the PI3K/AKT pathway, a key membrane-localized signaling hub that regulates cell survival, protein synthesis, and autophagy and gene expression. Our main focus is on how sphingolipids influence this pathway in muscle. However, understanding endogenous regulators of the AKT pathway is relevant to the vastly important medical problem of insulin- resistance and metabolic syndrome, whereas devising new pharmacological agents to inhibit PI3K/AKT signaling is a major objective in the treatment of cancer. Excessive autophagy underlies many human disease states including neurodegenerative diseases, cardiomyopathies, cancer, programmed cell death, and bacterial and viral infections. Thus, our research plan has potentially broad translational significance.
Funding Period: 2003-09-01 - 2015-02-28
more information: NIH RePORT

Top Publications

  1. ncbi Sphingosine 1-phosphate/sphingosine 1-phosphate receptor 1 signaling in rheumatoid synovium: regulation of synovial proliferation and inflammatory gene expression
    Masayasu Kitano
    Hyogo College of Medicine, Nishinomiya City, Hyogo, Japan
    Arthritis Rheum 54:742-53. 2006
  2. pmc An update on sphingosine-1-phosphate and other sphingolipid mediators
    Henrik Fyrst
    Center for Cancer Research, Children s Hospital Oakland Research Institute, Oakland, California, USA
    Nat Chem Biol 6:489-97. 2010
  3. pmc S1P lyase: a novel therapeutic target for ischemia-reperfusion injury of the heart
    Padmavathi Bandhuvula
    Children s Hospital Oakland Research Institute, Oakland, CA 94609 1673, USA
    Am J Physiol Heart Circ Physiol 300:H1753-61. 2011
  4. pmc A suppressor/enhancer screen in Drosophila reveals a role for wnt-mediated lipid metabolism in primordial germ cell migration
    Mark A McElwain
    Howard Hughes Medical Institute, Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
    PLoS ONE 6:e26993. 2011
  5. pmc Sphingosine-1-phosphate enhances satellite cell activation in dystrophic muscles through a S1PR2/STAT3 signaling pathway
    Kenneth C Loh
    Children s Hospital Oakland Research Institute, Oakland, California, United States of America
    PLoS ONE 7:e37218. 2012
  6. pmc S1P lyase in skeletal muscle regeneration and satellite cell activation: exposing the hidden lyase
    Julie D Saba
    Children s Hospital Oakland Research Institute, Oakland, CA 94609, USA
    Biochim Biophys Acta 1831:167-75. 2013
  7. pmc Sphingosine-1-phosphate lyase expression in embryonic and adult murine tissues
    Alexander D Borowsky
    Center for Comparative Medicine, University of California at Davis, Davis, CA 95616, USA
    J Lipid Res 53:1920-31. 2012
  8. pmc Immunohistochemical analysis of sphingosine phosphate lyase expression during murine development
    Susan Newbigging
    Centre for Modeling Human Disease, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, The Toronto Centre for Phenogenomics, University of Toronto, Toronto, Ontario, Canada
    Gene Expr Patterns 13:21-9. 2013
  9. pmc Natural sphingadienes inhibit Akt-dependent signaling and prevent intestinal tumorigenesis
    Henrik Fyrst
    Children s Hospital Oakland Research Institute, Oakland, California 94609 1673, USA
    Cancer Res 69:9457-64. 2009
  10. pmc Normalization of diabetic wound healing
    Kellie N Francis-Goforth
    Department of General Surgery, University of California San Francisco East Bay, Oakland, CA, USA
    Surgery 147:446-9. 2010

Research Grants

  1. The Center for Native and Pacific Health Disparities Research
    MARJORIE K LEIMOMI MALA MAU; Fiscal Year: 2013

Detail Information

Publications21

  1. ncbi Sphingosine 1-phosphate/sphingosine 1-phosphate receptor 1 signaling in rheumatoid synovium: regulation of synovial proliferation and inflammatory gene expression
    Masayasu Kitano
    Hyogo College of Medicine, Nishinomiya City, Hyogo, Japan
    Arthritis Rheum 54:742-53. 2006
    ..This study was undertaken to examine the role of S1P/S1P1 signaling in the pathogenesis of rheumatoid arthritis (RA)...
  2. pmc An update on sphingosine-1-phosphate and other sphingolipid mediators
    Henrik Fyrst
    Center for Cancer Research, Children s Hospital Oakland Research Institute, Oakland, California, USA
    Nat Chem Biol 6:489-97. 2010
    ....
  3. pmc S1P lyase: a novel therapeutic target for ischemia-reperfusion injury of the heart
    Padmavathi Bandhuvula
    Children s Hospital Oakland Research Institute, Oakland, CA 94609 1673, USA
    Am J Physiol Heart Circ Physiol 300:H1753-61. 2011
    ..These results reveal, for the first time, that SPL is an ischemia-induced enzyme that can be targeted as a novel strategy for preventing cardiac I/R injury...
  4. pmc A suppressor/enhancer screen in Drosophila reveals a role for wnt-mediated lipid metabolism in primordial germ cell migration
    Mark A McElwain
    Howard Hughes Medical Institute, Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
    PLoS ONE 6:e26993. 2011
    ..Our data are consistent with a model in which the activity of lipid phosphate phosphatases shapes a concentration gradient of ceramide-1-phosphate (C1P), the product of Dcerk, allowing proper PGC migration...
  5. pmc Sphingosine-1-phosphate enhances satellite cell activation in dystrophic muscles through a S1PR2/STAT3 signaling pathway
    Kenneth C Loh
    Children s Hospital Oakland Research Institute, Oakland, California, United States of America
    PLoS ONE 7:e37218. 2012
    ..Our findings suggest that S1P promotes SC progression through the cell cycle by repression of cell cycle inhibitors via S1PR2/STAT3-dependent signaling and that SPL inhibition may provide a therapeutic strategy for MD...
  6. pmc S1P lyase in skeletal muscle regeneration and satellite cell activation: exposing the hidden lyase
    Julie D Saba
    Children s Hospital Oakland Research Institute, Oakland, CA 94609, USA
    Biochim Biophys Acta 1831:167-75. 2013
    ..These findings reveal how S1P can activate SCs and indicate that SPL suppression may provide a therapeutic strategy for myopathies. This article is part of a Special Issue entitled Advances in Lysophospholipid Research...
  7. pmc Sphingosine-1-phosphate lyase expression in embryonic and adult murine tissues
    Alexander D Borowsky
    Center for Comparative Medicine, University of California at Davis, Davis, CA 95616, USA
    J Lipid Res 53:1920-31. 2012
    ..This unique expression pattern suggests SPL has many undiscovered physiological functions apart from its role in immunity...
  8. pmc Immunohistochemical analysis of sphingosine phosphate lyase expression during murine development
    Susan Newbigging
    Centre for Modeling Human Disease, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, The Toronto Centre for Phenogenomics, University of Toronto, Toronto, Ontario, Canada
    Gene Expr Patterns 13:21-9. 2013
    ..Our findings are consistent with the SPL expression pattern of the adult mouse and with congenital abnormalities observed in SPL mutant mice...
  9. pmc Natural sphingadienes inhibit Akt-dependent signaling and prevent intestinal tumorigenesis
    Henrik Fyrst
    Children s Hospital Oakland Research Institute, Oakland, California 94609 1673, USA
    Cancer Res 69:9457-64. 2009
    ..Thus, sphingadienes represent a new class of therapeutic and/or chemopreventive agents that blocks Akt signaling in neoplastic and preneoplastic cells...
  10. pmc Normalization of diabetic wound healing
    Kellie N Francis-Goforth
    Department of General Surgery, University of California San Francisco East Bay, Oakland, CA, USA
    Surgery 147:446-9. 2010
    ..Pharmacologic modulation of sphingosine-1-phosphate-dependent signaling normalizes healing in diabetic wounds...
  11. pmc Redirection of sphingolipid metabolism toward de novo synthesis of ethanolamine in Leishmania
    Kai Zhang
    Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, and Children s Hospital Oakland Research Institute, Center for Cancer Research, CA, USA
    EMBO J 26:1094-104. 2007
    ..Our results thus reveal a striking example of remodeling of the SL metabolic pathway in Leishmania...
  12. ncbi Sphingosine-1-phosphate lyase in immunity and cancer: silencing the siren
    Padmavathi Bandhuvula
    Children s Hospital Oakland Research Institute, Oakland, CA 94609, USA
    Trends Mol Med 13:210-7. 2007
    ....
  13. pmc Disruption of sphingolipid metabolism elicits apoptosis-associated reproductive defects in Drosophila
    Van H Phan
    Department of Biology and Molecular Biology Institute, San Diego State University, San Diego, and Children s Hospital Oakland Research Institute, CA, USA
    Dev Biol 309:329-41. 2007
    ..These data thus provide the first evidence in Drosophila that accumulated sphingolipids trigger elevated levels of apoptosis via the modulation of known signaling pathways...
  14. ncbi A rapid fluorescence assay for sphingosine-1-phosphate lyase enzyme activity
    Padmavathi Bandhuvula
    Children s Hospital, Oakland Research Institute, Oakland, CA 94609, USA
    J Lipid Res 48:2769-78. 2007
    ..Product inhibition was not observed using ethanolamine phosphate and a commercially available source of hexadecenal. This method is suitable for quantifying SPL activity in a variety of cell and tissue sources...
  15. ncbi Identification and characterization by electrospray mass spectrometry of endogenous Drosophila sphingadienes
    Henrik Fyrst
    Children s Hospital Oakland Research Institute, Oakland, CA 94609, USA
    J Lipid Res 49:597-606. 2008
    ..The temporal and spatial accumulation of Delta(4,6)-sphingadienes in Sply mutants suggests that these lipids may contribute to the muscle degeneration observed in these flies...
  16. pmc Sphingosine-1-phosphate lyase in development and disease: sphingolipid metabolism takes flight
    Henrik Fyrst
    Children s Hospital Oakland Research Institute, 5700 Martin Luther King Jr Way, Oakland, CA 94609, USA
    Biochim Biophys Acta 1781:448-58. 2008
    ..This review provides an overview of our current understanding of SPL structure and function, mechanisms involved in SPL regulation and the role of SPL in development and disease...
  17. pmc Sphingosine 1-phosphate lyase enzyme assay using a BODIPY-labeled substrate
    Padmavathi Bandhuvula
    Cancer Biology Lab, Children s Hospital Oakland Research Institute, 5700 Martin Luther King Jr Way, Oakland, CA 94609, USA
    Biochem Biophys Res Commun 380:366-70. 2009
    ..The major aldehyde product is confirmed by reaction with 2,4-dinitrophenylhydrazine. The SPL-catalyzed reaction is linear over a 30 min time period and yields a K(m) of 35 microM for BODIPY-sphingosine 1-phosphate...
  18. pmc Lyase to live by: sphingosine phosphate lyase as a therapeutic target
    Ashok Kumar
    Children s Hospital Oakland Research Institute CHORI, Oakland, CA 94609 1673, USA
    Expert Opin Ther Targets 13:1013-25. 2009
    ..SPL has been directly implicated in various physiological and pathological processes, including cell stress responses, cancer, immunity, hematopoietic function, muscle homeostasis, inflammation and development...
  19. pmc Sphingosine phosphate lyase regulates myogenic differentiation via S1P receptor-mediated effects on myogenic microRNA expression
    Anabel S de la Garza-Rodea
    1Children s Hospital Oakland Research Institute, 5700 Martin Luther King Jr Way, Oakland, CA 94609, USA
    FASEB J 28:506-19. 2014
    ..Thus, we show for the first time that the S1P/SPL/S1P-receptor axis regulates the expression of a number of miRNAs, thereby contributing to myogenic differentiation...

Research Grants30

  1. The Center for Native and Pacific Health Disparities Research
    MARJORIE K LEIMOMI MALA MAU; Fiscal Year: 2013
    ..5) To prepare and empower our diverse Native and Pacific People communities to take ownership of their own health and wellness. ..