1
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Harioudh MK, Perez J, Chong Z, Nair S, So L, McCormick KD, Ghosh A, Shao L, Srivastava R, Soveg F, Ebert TS, Atianand MK, Hornung V, Savan R, Diamond MS, Sarkar SN. Oligoadenylate synthetase 1 displays dual antiviral mechanisms in driving translational shutdown and protecting interferon production. Immunity 2024; 57:446-461.e7. [PMID: 38423012 PMCID: PMC10939734 DOI: 10.1016/j.immuni.2024.02.002] [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: 06/15/2023] [Revised: 11/15/2023] [Accepted: 02/05/2024] [Indexed: 03/02/2024]
Abstract
In response to viral infection, how cells balance translational shutdown to limit viral replication and the induction of antiviral components like interferons (IFNs) is not well understood. Moreover, how distinct isoforms of IFN-induced oligoadenylate synthetase 1 (OAS1) contribute to this antiviral response also requires further elucidation. Here, we show that human, but not mouse, OAS1 inhibits SARS-CoV-2 replication through its canonical enzyme activity via RNase L. In contrast, both mouse and human OAS1 protect against West Nile virus infection by a mechanism distinct from canonical RNase L activation. OAS1 binds AU-rich elements (AREs) of specific mRNAs, including IFNβ. This binding leads to the sequestration of IFNβ mRNA to the endomembrane regions, resulting in prolonged half-life and continued translation. Thus, OAS1 is an ARE-binding protein with two mechanisms of antiviral activity: driving inhibition of translation but also a broader, non-canonical function of protecting IFN expression from translational shutdown.
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Affiliation(s)
- Munesh K Harioudh
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Microbiology and Molecular Genetics, Pittsburgh, PA, USA
| | - Joseph Perez
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Microbiology and Molecular Genetics, Pittsburgh, PA, USA
| | - Zhenlu Chong
- Departments of Medicine, Molecular Microbiology, Pathology & Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Sharmila Nair
- Departments of Medicine, Molecular Microbiology, Pathology & Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Lomon So
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA; Division of Immunology, Benaroya Research Institute, Seattle, WA, USA
| | - Kevin D McCormick
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Microbiology and Molecular Genetics, Pittsburgh, PA, USA
| | - Arundhati Ghosh
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Microbiology and Molecular Genetics, Pittsburgh, PA, USA
| | - Lulu Shao
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Microbiology and Molecular Genetics, Pittsburgh, PA, USA
| | - Rashmi Srivastava
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Microbiology and Molecular Genetics, Pittsburgh, PA, USA
| | - Frank Soveg
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Thomas S Ebert
- Department of Biochemistry, Ludwig Maximilians Universität, Munich, Germany
| | - Maninjay K Atianand
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Veit Hornung
- Department of Biochemistry, Ludwig Maximilians Universität, Munich, Germany
| | - Ram Savan
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Michael S Diamond
- Departments of Medicine, Molecular Microbiology, Pathology & Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Saumendra N Sarkar
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Microbiology and Molecular Genetics, Pittsburgh, PA, USA; Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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2
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So L, Obata-Ninomiya K, Hu A, Muir VS, Takamori A, Song J, Buckner JH, Savan R, Ziegler SF. Regulatory T cells suppress CD4+ effector T cell activation by controlling protein synthesis. J Exp Med 2023; 220:213791. [PMID: 36598533 PMCID: PMC9827529 DOI: 10.1084/jem.20221676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/20/2022] [Accepted: 12/07/2022] [Indexed: 01/05/2023] Open
Abstract
Regulatory T cells (Tregs) suppress the activation and subsequent effector functions of CD4 effector T cells (Teffs). However, molecular mechanisms that enforce Treg-mediated suppression in CD4 Teff are unclear. We found that Tregs suppressed activation-induced global protein synthesis in CD4 Teffs prior to cell division. We analyzed genome-wide changes in the transcriptome and translatome of activated CD4 Teffs. We show that mRNAs encoding for the protein synthesis machinery are regulated at the level of translation in activated CD4 Teffs by Tregs. Tregs suppressed global protein synthesis of CD4 Teffs by specifically inhibiting mRNAs of the translation machinery at the level of mTORC1-mediated translation control through concerted action of immunosuppressive cytokines IL-10 and TGFβ. Lastly, we found that the therapeutic targeting of protein synthesis with the RNA helicase eIF4A inhibitor rocaglamide A can alleviate inflammatory CD4 Teff activation caused by acute Treg depletion in vivo. These data show that peripheral tolerance is enforced by Tregs through mRNA translational control in CD4 Teffs.
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Affiliation(s)
- Lomon So
- Center for Fundamental Immunology, Benaroya Research Institute, Seattle, WA, USA,Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA
| | | | - Alex Hu
- Center for Systems Immunology, Benaroya Research Institute, Seattle, WA, USA
| | - Virginia S. Muir
- Center for Systems Immunology, Benaroya Research Institute, Seattle, WA, USA
| | - Ayako Takamori
- Center for Fundamental Immunology, Benaroya Research Institute, Seattle, WA, USA
| | - Jing Song
- Center for Fundamental Immunology, Benaroya Research Institute, Seattle, WA, USA
| | - Jane H. Buckner
- Center for Fundamental Immunology, Benaroya Research Institute, Seattle, WA, USA
| | - Ram Savan
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA,Correspondence to Ram Savan:
| | - Steven F. Ziegler
- Center for Fundamental Immunology, Benaroya Research Institute, Seattle, WA, USA,Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA,Steven F. Ziegler:
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3
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Allenspach EJ, Soveg F, Finn LS, So L, Gorman JA, Rosen ABI, Skoda-Smith S, Wheeler MM, Barrow KA, Rich LM, Debley JS, Bamshad MJ, Nickerson DA, Savan R, Torgerson TR, Rawlings DJ. Germline SAMD9L truncation variants trigger global translational repression. J Exp Med 2021; 218:211891. [PMID: 33724365 PMCID: PMC7970252 DOI: 10.1084/jem.20201195] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [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: 06/09/2020] [Revised: 01/07/2021] [Accepted: 02/12/2021] [Indexed: 12/11/2022] Open
Abstract
SAMD9L is an interferon-induced tumor suppressor implicated in a spectrum of multisystem disorders, including risk for myeloid malignancies and immune deficiency. We identified a heterozygous de novo frameshift variant in SAMD9L in an infant with B cell aplasia and clinical autoinflammatory features who died from respiratory failure with chronic rhinovirus infection. Autopsy demonstrated absent bone marrow and peripheral B cells as well as selective loss of Langerhans and Purkinje cells. The frameshift variant led to expression of a truncated protein with interferon treatment. This protein exhibited a gain-of-function phenotype, resulting in interference in global protein synthesis via inhibition of translational elongation. Using a mutational scan, we identified a region within SAMD9L where stop-gain variants trigger a similar translational arrest. SAMD9L variants that globally suppress translation had no effect or increased mRNA transcription. The complex-reported phenotype likely reflects lineage-dominant sensitivities to this translation block. Taken together, our findings indicate that interferon-triggered SAMD9L gain-of-function variants globally suppress translation.
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Affiliation(s)
- Eric J Allenspach
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA.,Department of Pediatrics, University of Washington, Seattle, WA.,Brotman Baty Institute for Precision Medicine, Seattle, WA
| | - Frank Soveg
- Department of Immunology, University of Washington, Seattle, WA
| | - Laura S Finn
- Department of Pathology and Laboratory Medicine, University of Washington, Seattle, WA
| | - Lomon So
- Department of Immunology, University of Washington, Seattle, WA.,Division of Immunology, Benaroya Research Institute, Seattle, WA
| | - Jacquelyn A Gorman
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA
| | - Aaron B I Rosen
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA
| | | | | | - Kaitlyn A Barrow
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA
| | - Lucille M Rich
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA
| | - Jason S Debley
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA.,Department of Pediatrics, University of Washington, Seattle, WA
| | - Michael J Bamshad
- Department of Pediatrics, University of Washington, Seattle, WA.,Genome Sciences, University of Washington, Seattle, WA.,Brotman Baty Institute for Precision Medicine, Seattle, WA
| | - Deborah A Nickerson
- Genome Sciences, University of Washington, Seattle, WA.,Brotman Baty Institute for Precision Medicine, Seattle, WA
| | - Ram Savan
- Department of Immunology, University of Washington, Seattle, WA
| | | | - David J Rawlings
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA.,Department of Pediatrics, University of Washington, Seattle, WA.,Department of Immunology, University of Washington, Seattle, WA
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4
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Perez J, Harioudh MK, So L, Nair S, McCormick K, Ghosh A, Shao L, Srivastava R, Ebert T, Atianand M, Hornung V, Diamond MS, Savan R, Sarkar SN. Oligoadenylate Synthetase 1 enhances DNA sensor cGAS translation to mediate WNV antiviral activity. The Journal of Immunology 2020. [DOI: 10.4049/jimmunol.204.supp.249.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
Interferons inhibit virus replication through the expression of interferon stimulated genes (ISGs). We have found that a specific isoform of one such ISG, Oligoadenylate Synthetase 1 (OAS1) limits host susceptibility to West Nile Virus (WNV) infection through a non-canonical mechanism. This OAS1 isoform (OAS1 P46) in humans is generated due to an alternative splice acceptor site at the C-terminus of OAS1 gene. The SNP rs10774671 at this site has been associated with disease severity to WNV. We show that human OAS1-KO cells have lower basal levels of cGAS protein and can be rescued by OAS1 P46 independent of its enzyme activity. Additionally, through RNA-seq, SILAC, polysome profiling and radiolabeling experiments, we show that OAS1 does not regulate mRNA transcription but instead enhances protein translation of a select set of mRNAs, thereby increasing the steady state and induced levels of specific proteins with antiviral properties. Inducible expression of OAS1 P46 in cGAS-KO cells does not suppress WNV replication, suggesting that the antiviral activity of OAS1 is mediated through cGAS. We also have established functional equivalence between OAS1 P46 and a mouse ortholog, Oas1b (no enzyme activity), which similarly affects WNV susceptibility. Oas1b inhibits WNV infection and pathogenesis in vivo and inhibits WNV infection in vitro in cGAS-dependent manner. Through RNA-protein crosslinking experiments we have identified target mRNAs that bind to OAS1 and have demonstrated increased sensitivity of WNV in Oas1b RNA binding mutants. Our findings suggest a novel mechanism of OAS1 in which it binds to target mRNAs, enhances the translation of these RNAs and limits virus infection.
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Affiliation(s)
- Joseph Perez
- 1Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA
- 2Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Munesh K. Harioudh
- 1Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA
- 2Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Lomon So
- 3Department of Immunology, University of Washington School of Medicine, Seattle, WA
| | - Sharmila Nair
- 4Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO
| | - Kevin McCormick
- 2Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Arundhati Ghosh
- 1Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA
- 2Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Lulu Shao
- 1Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA
- 2Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Rashmi Srivastava
- 1Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA
- 2Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Thomas Ebert
- 5Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Munic, Germany
| | - Maninjay Atianand
- 6Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Veit Hornung
- 5Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Munic, Germany
| | - Michael S. Diamond
- 4Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO
| | - Ram Savan
- 3Department of Immunology, University of Washington School of Medicine, Seattle, WA
| | - Saumendra N. Sarkar
- 1Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA
- 2Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA
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5
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Schwerk J, Soveg FW, Ryan AP, Thomas KR, Hatfield LD, Ozarkar S, Forero A, Kell AM, Roby JA, So L, Hyde JL, Gale M, Daugherty MD, Savan R. RNA-binding protein isoforms ZAP-S and ZAP-L have distinct antiviral and immune resolution functions. Nat Immunol 2019; 20:1610-1620. [PMID: 31740798 DOI: 10.1038/s41590-019-0527-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 09/26/2019] [Indexed: 12/22/2022]
Abstract
The initial response to viral infection is anticipatory, with host antiviral restriction factors and pathogen sensors constantly surveying the cell to rapidly mount an antiviral response through the synthesis and downstream activity of interferons. After pathogen clearance, the host's ability to resolve this antiviral response and return to homeostasis is critical. Here, we found that isoforms of the RNA-binding protein ZAP functioned as both a direct antiviral restriction factor and an interferon-resolution factor. The short isoform of ZAP bound to and mediated the degradation of several host interferon messenger RNAs, and thus acted as a negative feedback regulator of the interferon response. In contrast, the long isoform of ZAP had antiviral functions and did not regulate interferon. The two isoforms contained identical RNA-targeting domains, but differences in their intracellular localization modulated specificity for host versus viral RNA, which resulted in disparate effects on viral replication during the innate immune response.
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Affiliation(s)
- Johannes Schwerk
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Frank W Soveg
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Andrew P Ryan
- Section of Molecular Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Kerri R Thomas
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Lauren D Hatfield
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Snehal Ozarkar
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Adriana Forero
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Alison M Kell
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Justin A Roby
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Lomon So
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA.,Immunology Program, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
| | - Jennifer L Hyde
- Department of Microbiology, School of Medicine, University of Washington, Seattle, WA, USA
| | - Michael Gale
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA.,Center for Innate Immunity and Immune Disease, University of Washington, Seattle, WA, USA
| | - Matthew D Daugherty
- Section of Molecular Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA.
| | - Ram Savan
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA, USA. .,Center for Innate Immunity and Immune Disease, University of Washington, Seattle, WA, USA.
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6
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Forero A, Ozarkar S, Li H, Lee CH, Hemann EA, Nadjsombati MS, Hendricks MR, So L, Green R, Roy CN, Sarkar SN, von Moltke J, Anderson SK, Gale M, Savan R. Differential Activation of the Transcription Factor IRF1 Underlies the Distinct Immune Responses Elicited by Type I and Type III Interferons. Immunity 2019; 51:451-464.e6. [PMID: 31471108 DOI: 10.1016/j.immuni.2019.07.007] [Citation(s) in RCA: 139] [Impact Index Per Article: 27.8] [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: 05/29/2018] [Revised: 05/20/2019] [Accepted: 07/25/2019] [Indexed: 12/21/2022]
Abstract
Type I and III interferons (IFNs) activate similar downstream signaling cascades, but unlike type I IFNs, type III IFNs (IFNλ) do not elicit strong inflammatory responses in vivo. Here, we examined the molecular mechanisms underlying this disparity. Type I and III IFNs displayed kinetic differences in expression of IFN-stimulated genes and proinflammatory responses, with type I IFNs preferentially stimulating expression of the transcription factor IRF1. Type III IFNs failed to induce IRF1 expression because of low IFNλ receptor abundance and insufficient STAT1 activation on epithelial cells and thus did not activate the IRF1 proinflammatory gene program. Rather, IFNλ stimulation preferentially induced factors implicated in tissue repair. Our findings suggest that IFN receptor compartmentalization and abundance confer a spatiotemporal division of labor where type III IFNs control viral spread at the site of the infection while restricting tissue damage; the transient induction of inflammatory responses by type I IFNs recruits immune effectors to promote protective immunity.
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Affiliation(s)
- Adriana Forero
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Snehal Ozarkar
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Hongchuan Li
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Chia Heng Lee
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Emily A Hemann
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Marija S Nadjsombati
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Matthew R Hendricks
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Lomon So
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Richard Green
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA; Center for Innate Immunity and Immune Disease, University of Washington, Seattle, WA 98109, USA
| | - Chandra N Roy
- University of Pittsburgh Cancer Institute, Pittsburgh, PA 15232, USA
| | | | - Jakob von Moltke
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Stephen K Anderson
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA; Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Michael Gale
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA; Center for Innate Immunity and Immune Disease, University of Washington, Seattle, WA 98109, USA
| | - Ram Savan
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA; Center for Innate Immunity and Immune Disease, University of Washington, Seattle, WA 98109, USA.
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7
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So L, Lee J, Palafox M, Mallya S, Woxland CG, Arguello M, Truitt ML, Sonenberg N, Ruggero D, Fruman DA. The 4E-BP-eIF4E axis promotes rapamycin-sensitive growth and proliferation in lymphocytes. Sci Signal 2016; 9:ra57. [PMID: 27245614 DOI: 10.1126/scisignal.aad8463] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Rapamycin has been used as a clinical immunosuppressant for many years; however, the molecular basis for its selective effects on lymphocytes remains unclear. We investigated the role of two canonical effectors of the mammalian target of rapamycin (mTOR): ribosomal S6 kinases (S6Ks) and eukaryotic initiation factor 4E (eIF4E)-binding proteins (4E-BPs). S6Ks are thought to regulate cell growth (increase in cell size), and 4E-BPs are thought to control proliferation (increase in cell number), with mTORC1 signaling serving to integrate these processes. However, we found that the 4E-BP-eIF4E signaling axis controlled both the growth and proliferation of lymphocytes, processes for which the S6Ks were dispensable. Furthermore, rapamycin disrupted eIF4E function selectively in lymphocytes, which was due to the increased abundance of 4E-BP2 relative to that of 4E-BP1 in these cells and the greater sensitivity of 4E-BP2 to rapamycin. Together, our findings suggest that the 4E-BP-eIF4E axis is uniquely rapamycin-sensitive in lymphocytes and that this axis promotes clonal expansion of these cells by coordinating growth and proliferation.
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Affiliation(s)
- Lomon So
- Department of Molecular Biology and Biochemistry, and Institute for Immunology, University of California, Irvine, Irvine, CA 92697, USA
| | - Jongdae Lee
- Department of Molecular Biology and Biochemistry, and Institute for Immunology, University of California, Irvine, Irvine, CA 92697, USA. Department of Medicine, University of California, San Diego, San Diego, CA 92103, USA
| | - Miguel Palafox
- Department of Molecular Biology and Biochemistry, and Institute for Immunology, University of California, Irvine, Irvine, CA 92697, USA
| | - Sharmila Mallya
- Department of Molecular Biology and Biochemistry, and Institute for Immunology, University of California, Irvine, Irvine, CA 92697, USA
| | - Chaz G Woxland
- Department of Molecular Biology and Biochemistry, and Institute for Immunology, University of California, Irvine, Irvine, CA 92697, USA
| | - Meztli Arguello
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, Quebec H3A 1A3, Canada
| | - Morgan L Truitt
- School of Medicine and Department of Urology, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, Quebec H3A 1A3, Canada
| | - Davide Ruggero
- School of Medicine and Department of Urology, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
| | - David A Fruman
- Department of Molecular Biology and Biochemistry, and Institute for Immunology, University of California, Irvine, Irvine, CA 92697, USA.
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8
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Chiu H, So L, Fruman DA. A Novel Role for the 4E-BP/eIF4E Axis in B Cell Antibody Class Switching. The Journal of Immunology 2016. [DOI: 10.4049/jimmunol.196.supp.56.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
During an immune response, activated B cells give rise to antibody secreting plasma cells to fight infection. B cells undergo a process known as antibody class switch recombination (CSR) to produce different classes of antibodies with varying effector functions. The mammalian target of Rapamycin (mTOR) signaling pathway is activated during this process and inhibition of mTOR suppresses both proliferation and differentiation into antibody secreting cells. mTOR is a kinase that is found in two distinct complexes, mTORC1 and mTORC2 and B cells deficient in mTOR have impaired survival, proliferation and differentiation. It has been shown that antibody class switch recombination requires B cell division, however it is unclear if there is another regulatory mechanism through mTOR that is independent of proliferation. The mTORC1 inhibitor rapamycin, at either low concentrations or when added after a B cell has committed to divide, suppresses class switching while preserving proliferation. Mechanistic investigation of the mTORC1 substrate 4E-BP, an inhibitor of eIF4E and cap-dependent translation, showed that blocking the 4E-BP/eIF4E axis can decrease antibody class switching independently of proliferation. Genetic deletion of 4E-BP1 and 4E-BP2 isoforms partially rescues from the effects of rapamycin on class switching to IgG1. These results uncover a novel role for mTORC1 and the 4E-BP/eIF4E axis in B cell antibody class switching, suggesting that cap-dependent translation regulates key steps in B cell differentiation. Further study of this pathway may provide mechanistic insight into antibody-mediated autoimmune diseases such as lupus and arthritis.
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9
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Vo TT, Lee JHS, So L, Beagle B, Janes MR, Fruman DA. Abstract IA16: Mechanisms of resistance to mTOR inhibitors in leukemia and lymphoma. Mol Cancer Ther 2015. [DOI: 10.1158/1538-8514.pi3k14-ia16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Targeting mTOR signaling is a promising approach for treating blood cancers. We reported that mTOR kinase inhibitors, including PP242 and MLN0128, synergize with ABL tyrosine kinase inhibitors (TKIs) to cause cell cycle arrest and death in acute leukemia cells driven by BCR-ABL. mTOR kinase inhibitors are more effective than rapamycin in these models and have minimal effects on normal hematopoietic cells and immune responses at anti-leukemic doses. Ongoing studies indicate that mTOR kinase inhibitors are immunosuppressive at slightly higher concentrations. Moreover, the compounds are generally not cytotoxic as single agents in leukemia or lymphoma models. These findings emphasize the need for rational combinations to unleash the therapeutic potential of mTOR kinase inhibitors. To this end, we have tested various classes of anti-cancer agents guided by gene expression and proteomic data. Our data reveal synergies between mTOR kinase inhibitors with histone deacetylase inhibitors in B-ALL, and with BCL2 antagonists in DLBCL. Unexpectedly, mTOR kinase inhibitors protect B-ALL cells from methotrexate and 6-mercaptopurine, chemotherapeutic agents used in the treatment of B-ALL patients. ABL TKIs can also protect B-ALL cells from methotrexate by inhibiting downstream mTOR signaling. Together these studies identify potential applications and limitations of mTOR-targeted therapy in blood cancers.
Citation Format: Thanh-Trang Vo, Jong-Hoon Scott Lee, Lomon So, Brandon Beagle, Matthew R. Janes, David A. Fruman. Mechanisms of resistance to mTOR inhibitors in leukemia and lymphoma. [abstract]. In: Proceedings of the AACR Special Conference: Targeting the PI3K-mTOR Network in Cancer; Sep 14-17, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(7 Suppl):Abstract nr IA16.
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Affiliation(s)
| | | | - Lomon So
- University of California, Irvine, CA
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10
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Abstract
Mouse models lacking proteins essential for autophagosome formation have demonstrated that autophagy plays a critical role in T cell development and activation. To better understand the function of autophagy in quiescent and activated lymphocytes, we have generated a mouse deficient in rab7 selectively in T cells and compared the effects of blocking autophagy at an early (atg5(-/-)) or late (rab7(-/-)) stage on T cell biology. rab7(-/-) murine embryonic fibroblasts (MEFs) and T cells generated from these mice exhibit a profound block in autophagosome degradation and are as sensitive as atg5(-/-) cells to extracellular nutrient limitation. Rab7(flox/flox)CD4-Cre(+) mice lacking the RAB7 protein in both CD4 and CD8 T cells had reduced numbers of peripheral T cells, but this defect was not as severe as in Atg5(flox/flox)CD4-Cre(+) mice despite efficient rab7 deletion and inhibition of autophagic flux. This difference may stem from the reduced ROS generation and enhanced survival of rab7(-/-) T cells compared with wild-type and atg5(-/-) T cells in the absence of cytokine stimulation. rab7(-/-) and atg5(-/-) T cells exhibited similar defects in proliferation both following antibody-mediated T cell receptor (TCR) cross-linking and using a more physiologic activation protocol, allogeneic stimulation. Interestingly, autophagy was not required to provide building blocks for the upregulation of nutrient transporter proteins immediately following activation. Together, these studies suggest that autophagosome degradation is required for the survival of activated T cells, but that loss of rab7 is better tolerated in naïve T cells than the loss of atg5.
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Affiliation(s)
- Saurabh Ghosh Roy
- Department of Developmental and Cell Biology; University of California, Irvine; Irvine, CA USA
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11
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So L, Yea SS, Oak JS, Lu M, Manmadhan A, Ke QH, Janes MR, Kessler LV, Kucharski JM, Li LS, Martin MB, Ren P, Jessen KA, Liu Y, Rommel C, Fruman DA. Selective inhibition of phosphoinositide 3-kinase p110α preserves lymphocyte function. J Biol Chem 2012; 288:5718-31. [PMID: 23275335 DOI: 10.1074/jbc.m112.379446] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Class IA phosphoinositide 3-kinase (PI3K) is essential for clonal expansion, differentiation, and effector function of B and T lymphocytes. The p110δ catalytic isoform of PI3K is highly expressed in lymphocytes and plays a prominent role in B and T cell responses. Another class IA PI3K catalytic isoform, p110α, is a promising drug target in cancer but little is known about its function in lymphocytes. Here we used highly selective inhibitors to probe the function of p110α in lymphocyte responses in vitro and in vivo. p110α inhibition partially reduced B cell receptor (BCR)-dependent AKT activation and proliferation, and diminished survival supported by the cytokines BAFF and IL-4. Selective p110δ inhibition suppressed B cell responses much more strongly, yet maximal suppression was achieved by targeting multiple PI3K isoforms. In mouse and human T cells, inhibition of single class IA isoforms had little effect on proliferation, whereas pan-class I inhibition did suppress T cell expansion. In mice, selective p110α inhibition using the investigational agent MLN1117 (previously known as INK1117) did not disrupt the marginal zone B cell compartment and did not block T cell-dependent germinal center formation. In contrast, the selective p110δ inhibitor IC87114 strongly suppressed germinal center formation and reduced marginal zone B cell numbers, similar to a pan-class I inhibitor. These findings show that although acute p110α inhibition partially diminishes AKT activation, selective p110α inhibitors are likely to be less immunosuppressive in vivo compared with p110δ or pan-class I inhibitors.
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Affiliation(s)
- Lomon So
- Department of Molecular Biology & Biochemistry, and Institute for Immunology, University of California, Irvine, California 92697, USA
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Januel JM, Couris CM, Luthi JC, Halfon P, Trombert-Paviot B, Quan H, Drosler S, Sundararajan V, Pradat E, Touzet S, Wen E, Shepheard J, Webster G, Romano P, So L, Moskal L, Tournay-Lewis L, Sundaresan L, Kelley E, Klazinga N, Ghali W, Colin C, Burnand B. Adaptation au codage CIM-10 de 15 indicateurs de la sécurité des patients proposés par l’Agence étasunienne pour la recherche et la qualité des soins de santé (AHRQ). Rev Epidemiol Sante Publique 2011; 59:341-50. [DOI: 10.1016/j.respe.2011.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 02/10/2011] [Accepted: 04/01/2011] [Indexed: 10/17/2022] Open
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13
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Even Y, Bennett JL, Sekulovic S, So L, Yi L, McNagny K, Humphries RK, Rossi FMV. NUP98-HOXA10hd-expanded hematopoietic stem cells efficiently reconstitute bone marrow of mismatched recipients and induce tolerance. Cell Transplant 2010; 20:1099-108. [PMID: 21092410 DOI: 10.3727/096368910x545068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Gene therapy as well as methods capable of returning cells to a pluripotent state (iPS) have enabled the correction of genetic deficiencies in syngenic adult progenitors, reducing the need for immunosuppression in cell therapy approaches. However, in diseases involving mutations that lead to the complete lack of a protein, such as Duchenne muscular dystrophy, the main immunogens leading to rejection of transplanted cells are the therapeutic proteins themselves. In these cases even iPS cells would not circumvent the need for immunosuppression, and alternative strategies must be developed. One such potential strategy seeks to induce immune tolerance using hematopoietic stem cells originated from the same donor or iPS line from which the therapeutic progenitors are derived. However, donor hematopoietic stem cells (HSCs) are available in limiting numbers and embryonic stem (ES) cell-derived HSCs engraft poorly in adults. While these limitations have been circumvented by ectopic expression of HOXB4, overexpression of this protein is associated with inefficient lymphoid reconstitution. Here we show that adult HSCs expanded with a NUP98- HOXA10hd fusion protein sustain long-term engraftment in immunologically mismatched recipients and generate normal numbers of lymphoid cells. In addition, NUP98-HOXA10hd-expanded cells induce functional immune tolerance to a subsequent transplant of myogenic progenitors immunologically matched with the transplanted HSCs.
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Affiliation(s)
- Y Even
- Department of Medicine, The Biomedical Research Centre, University of British Columbia, Vancouver, BC, Canada
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14
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Fruman DA, Janes MR, Limon JJ, So L, Chen J, Martin MB, Ren P, Liu Y, Rommel C. Abstract 1798: TORC1/2 inhibitors have more potent anti-leukemic efficacy and are less immunosuppressive than rapamycin. Cancer Res 2010. [DOI: 10.1158/1538-7445.am10-1798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The purpose of this study was to evaluate the anti-leukemic and immunosuppressive properties of novel, ATP-competitive inhibitors of the mammalian target of rapamycin (mTOR). The mTOR inhibitors currently in clinical use, exemplified by rapamycin and related analogs (“rapalogs”), have achieved some success as anticancer therapies. However, these agents also suppress proliferation of both B and T lymphocytes. In addition, rapalogs have a mechanistic limitation: not only are they allosteric inhibitors that selectively bind to mTOR complex-1 (TORC1) and not to mTOR complex-2 (TORC2), but they do not fully inhibit TORC1. In contrast, novel ATP-competitive active-site inhibitors of the mTOR kinase overcome these limitations, displaying full inhibitory activity of both TORC1 and TORC2. We compared rapamycin with active-site TORC1/2 inhibitors in models of Philadelphia chromosome-positive pre-B acute lymphoblastic leukemia (Ph+ B-ALL). We find that PP242 and INK128, active-site TORC1/2 inhibitors, but not rapamycin cause death of murine and primary human leukemia cells. These compounds are also more potent than rapamycin in growth assays of solid tumor cell lines. Biochemical assays confirm that PP242 and INK128 inhibit rapamycin-resistant outputs of both TORC1 and TORC2. In vivo, oral administration of PP242 or INK128 delays leukemia onset and augments the effects of tyrosine kinase inhibitors. Surprisingly, active-site TORC1/2 inhibitors have much weaker effects on proliferation and function of normal B and T cells than rapamycin. Selective TORC1/2 inhibitors are also less immunosuppressive than PI-103, a panPI3K-mTORC1/2 inhibitor. These findings establish that transformed lymphocytes are selectively sensitive to TORC1/2 inhibitors and support the development of such inhibitors for leukemia therapy.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1798.
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Affiliation(s)
| | | | | | | | | | | | | | - Yi Liu
- 2Intellikine, La Jolla, CA
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15
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Janes MR, Limon JJ, So L, Chen J, Lim RJ, Chavez MA, Vu C, Lilly MB, Mallya S, Ong ST, Konopleva M, Martin MB, Ren P, Liu Y, Rommel C, Fruman DA. Effective and selective targeting of leukemia cells using a TORC1/2 kinase inhibitor. Nat Med 2010; 16:205-13. [PMID: 20072130 DOI: 10.1038/nm.2091] [Citation(s) in RCA: 292] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 12/23/2009] [Indexed: 02/08/2023]
Abstract
Targeting the mammalian target of rapamycin (mTOR) protein is a promising strategy for cancer therapy. The mTOR kinase functions in two complexes, TORC1 (target of rapamycin complex-1) and TORC2 (target of rapamycin complex-2); however, neither of these complexes is fully inhibited by the allosteric inhibitor rapamycin or its analogs. We compared rapamycin with PP242, an inhibitor of the active site of mTOR in both TORC1 and TORC2 (hereafter referred to as TORC1/2), in models of acute leukemia harboring the Philadelphia chromosome (Ph) translocation. We demonstrate that PP242, but not rapamycin, causes death of mouse and human leukemia cells. In vivo, PP242 delays leukemia onset and augments the effects of the current front-line tyrosine kinase inhibitors more effectively than does rapamycin. Unexpectedly, PP242 has much weaker effects than rapamycin on the proliferation and function of normal lymphocytes. PI-103, a less selective TORC1/2 inhibitor that also targets phosphoinositide 3-kinase (PI3K), is more immunosuppressive than PP242. These findings establish that Ph(+) transformed cells are more sensitive than normal lymphocytes to selective TORC1/2 inhibitors and support the development of such inhibitors for leukemia therapy.
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Affiliation(s)
- Matthew R Janes
- Department of Molecular Biology & Biochemistry, Institute for Immunology, University of California-Irvine, Irvine, California, USA
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16
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Januel JM, Couris CM, Quan H, Luthi JC, Drosler S, Sundararajan V, Trombert-Paviot B, Pradat E, Touzet S, Halfon P, Wen E, Shepheart J, Webster G, Romano P, So L, Moskal L, Tournay-Lewis L, Sundaresan L, Kelley E, Klazinga N, Ghali W, Burnand B, Colin C. Adaptation à la classification CIM-10 d’indicateurs de la sécurité des soins à l’hôpital développés à partir des données médico-administratives : le projet PSI. Rev Epidemiol Sante Publique 2008. [DOI: 10.1016/j.respe.2008.02.063] [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: 11/29/2022] Open
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17
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Heine H, Bohunek L, Johnson A, So L, Pate G, Fong P, Rossi F, Podor T. 256 INTRAVENOUS AND DIRECT MYOCARDIAL INJECTION OF SIDE POPULATION STEM CELLS LABELED WITH GREEN FLUORESCENT PROTEIN INTO A MURINE MODEL OF MYOCARDIAL INFARCTION. J Investig Med 2006. [DOI: 10.2310/6650.2005.x0004.255] [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: 11/18/2022]
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18
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So L, Ng N, Bilek M, Pigram PJ, Brack N. X-ray photoelectron spectroscopic study of the surface chemistry of soda-lime glass in vacuum. SURF INTERFACE ANAL 2006. [DOI: 10.1002/sia.2222] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Heine H, Bohunek L, Johnson A, So L, Pate G, Fong P, Rossi F, Podor T. Intravenous and Direct Myocardial Injection of Side Population Stem Cells Labeled with Green Fluorescent Protein into a Murine Model of Myocardial Infarction. J Investig Med 2006. [DOI: 10.1177/108155890605401s139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- H. Heine
- Program, University of British Columbia, Vancouver, BC
- iCAPTURE Centre, University of British Columbia, Vancouver, BC
| | - L. Bohunek
- iCAPTURE Centre, University of British Columbia, Vancouver, BC
| | - A. Johnson
- iCAPTURE Centre, University of British Columbia, Vancouver, BC
| | - L. So
- iCAPTURE Centre, University of British Columbia, Vancouver, BC
| | - G. Pate
- iCAPTURE Centre, University of British Columbia, Vancouver, BC
| | - P. Fong
- iCAPTURE Centre, University of British Columbia, Vancouver, BC
| | - F. Rossi
- Biomedical Research Centre, University of British Columbia, Vancouver, BC
| | - T. Podor
- iCAPTURE Centre, University of British Columbia, Vancouver, BC
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Heine H, Bohunek L, Johnson A, So L, Pate G, Fong P, McManus BM, Rossi F, Podor T. 248 INTRAVENOUS AND DIRECT MYOCARDIAL INJECTION OF SIDE POPULATION STEM CELLS LABELED WITH GREEN FLUORESCENT PROTEIN INTO A MURINE MODEL OF MYOCARDIAL INFARCTION. J Investig Med 2005. [DOI: 10.2310/6650.2005.00005.247] [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: 11/18/2022]
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21
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So L. International Society on Thrombosis and Haemostasis--XVIIIth congress. Oral presentations. IDrugs 2001; 4:989-93. [PMID: 15965838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Affiliation(s)
- L So
- Current Drugs Ltd, Middlesex House, 34-42 Cleveland Street, London, W1T 4LB, UK.
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So L. Boosting your product pipeline through innovative licensing. Pinpointing and managing successful alliances to remain competitive. IDrugs 2001; 4:1027-30. [PMID: 15965849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
With the recent outbreak of large mergers and acquisitions and the looming pipeline crisis among large pharmaceutical companies, this meeting aimed to bring together senior officers from the business development and licensing sectors of top biotech and pharma companies, to discuss all aspects of licensing with a focus on remaining competitive. Along with in-depth analyses and theories delivered by representatives from investment banks, consultancy firms and academia, the conference presented delegates with interesting viewpoints and practical advice on partnering strategies, and issues surrounding licensing.
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Affiliation(s)
- L So
- Current Drugs Ltd, Middlesex House, 34-42 Cleveland Street, London, W1T 4LB, UK.
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23
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So L. International Society on Thrombosis and Haemostasis--XVIIIth congress. Poster presentations. IDrugs 2001; 4:994-9. [PMID: 15965839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Affiliation(s)
- L So
- Current Drugs Ltd, Middlesex House, 34-42 Cleveland Street, London, W1T 4LB, UK.
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So L. International Society on Thrombosis and Haemostasis--XVIIIth congress. Managing thromboembolic disease in adults and children. IDrugs 2001; 4:1000-1. [PMID: 15965840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Affiliation(s)
- L So
- Current Drugs Ltd, Middlesex House, 34-42 Cleveland Street, London, W1T 4LB, UK.
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So L, White R, Arison B, Petuch B, Schwartz MS, Cheng H, Monaghan R, Chen TS. Microbial transformation of N-heptyl physostigmine, a semisynthetic alkaloid inhibitor of cholinesterase. J Ind Microbiol 1995; 15:108-11. [PMID: 7576461 DOI: 10.1007/bf01569808] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The microbiological transformation of N-heptyl physostigmine (L-693,487) (1), a semisynthetic physostigmine cholinesterase inhibitor, was investigated using Verticillium lecanii MF 5713 (ATCC 74148), Acremonium sp MF 5723 (ATCC 74164) and Actinoplanes sp MA 6559 (ATCC 53771). Nine microbial metabolites (2-10) of 1 were isolated and purified using reversed-phase HPLC. The structures of the metabolites were established using spectroscopic techniques including MS and NMR. Some of the microbial metabolites were identical to metabolites present in urine of a dog treated with 1.
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Affiliation(s)
- L So
- Merck Research Laboratories, Department of Fermentation Microbiology, Rahway, NJ 07065, USA
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Affiliation(s)
- B J Kendall
- Division of Gastroenterology, University of California Los Angeles Medical Center, USA
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Abstract
The microbial metabolism of MK 954 (Fig. 1), a novel nonpeptide angiotensin II receptor antagonist, was investigated using 40 microorganisms in an initial screen for cultures that will produce metabolites similar to those produced in the mammalian liver. The microbial transformation occurred under aerobic conditions in shake flasks incubated at 27 degrees C. Three metabolites of MK 954 were isolated and identified as the 1'-hydroxy M2, 3'-hydroxy M1, and glucuronic acid conjugated M3 derivatives. The structures of the metabolites were established by UV, 1H-NMR spectroscopy and FAB-MS spectrometry and are identical to metabolites produced by incubation of MK 954 with mammalian liver slices.
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Affiliation(s)
- T S Chen
- Merck Research Laboratories, Rahway, New Jersey 07065
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King NM, So L. A laboratory fabricated fixed appliance for extruding anterior teeth with subgingival fractures. Pediatr Dent 1988; 10:108-10. [PMID: 3269518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Abstract
Successive fiber fractions isolated from individual bovine lenses were fractionated to examine changes in lens proteins and membrane lipids as a function of age. In calf lens of about 1.2 gm wet weight, cholesterol (C) is maintained at a level of 3.3 microgram/mg dry weight in the outer cortical 30% of the lens. In the inner cortex, a C content of 2.4 micrograms/mg was found that decreased somewhat to 2.1 micrograms/mg in the inner nuclear 20% of the lens. The almost linear decrease in phospholipid (P) content from 11.6 in the cortex to 1.7 micrograms/mg in the nucleus resulted in a cortex to nucleus increase in C/P ratio from 0.5 to about 2.0 (mol/mol). Compared to calf lenses, a low C level of 2.4 micrograms/mg was observed in the outer cortex of cow lenses (approximately 3.0 gm wet weight). No significant difference in C level was found between the calf and cow lenses either in the inner cortical or nuclear regions. The P level was reduced to 6 and 1.2 micrograms/mg in the outer cortex and nucleus of the cow lens, respectively. The low nuclear P content is responsible for the observed high C/P value of 3.6. The lower lipid content found in the cortex of older lens suggests an age dependent decrease in the amount of available membrane lipid to envelope the newly formed fibers. A cortex to nucleus increase in the amount of urea-soluble (US) protein fraction from about 6 to 14% of total fiber mass was observed with the calf lens. In the cow lenses, the nuclear US fraction accounts for almost 30% of the fiber.(ABSTRACT TRUNCATED AT 250 WORDS)
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Li LK, So L, Spector A. Age-dependent changes in the distribution and concentration of human lens cholesterol and phospholipids. Biochim Biophys Acta 1987; 917:112-20. [PMID: 3790601 DOI: 10.1016/0005-2760(87)90291-8] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Analyses of total lipid in individual lenses 1.8-63 years of age indicate that both the cholesterol and the phospholipid concentrations have reached a high level of 10 and 14 micrograms/mg lens dry weight, respectively, after the first ten years of growth. Thereafter, the rate of phospholipid accumulation was greatly reduced to a value of 0.05 microgram/mg per year while that of cholesterol reduced to 0.19. Analyses of the distribution of lipid in successive lens fiber layers indicate that both the cholesterol and phospholipid levels increase in the entire lens between the age of 1.8 and 9 years. Older lenses showed a continuous increase in the accumulation of cholesterol in the deep cortical fibers, while little or no increase in phospholipid concentration was observed. These results indicate that the accumulation of lipids is greater than that of lens dry mass (protein) during the first decade of lens growth. Since more than 90% of lenticular lipids are associated with fiber cell membranes, these data suggest a gradual change in the differentiation of the newly formed secondary fibers from the epithelium during this period. Analyses of the phospholipid composition of the successive fiber fractions indicate that the major phospholipids of phosphatidyl ethanolamine (PE), phosphatidylserine (PS) and sphingomyelin maintained a uniform distribution in the 1.8- and 5-year-old lenses. While no change was observed with the cortical fibers, older lenses showed a gradual loss of PE and PS in the nuclear fiber up to 63 years of age. By the late teen years, nuclear PS can no longer be detected, while high levels of PE are maintained in lens nucleus. The disappearance of nuclear PE begins in the teen years and is completed by the age of 40. The decrease in PE and PS resulted in a continuous increase in the cholesterol/phospholipid ratio, a measure of membrane rigidity in the nuclear fiber in lenses 20 years of age and older. This decrease is also responsible for the exceedingly high rigidity of the nuclear fibers of lenses 60 years of age and older. Possible lamellar cholesterol organization in the lens fiber membrane is discussed.
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Li LK, So L, Spector A. Membrane cholesterol and phospholipid in consecutive concentric sections of human lenses. J Lipid Res 1985; 26:600-9. [PMID: 4020298] [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: 01/08/2023] Open
Abstract
Lens membrane preparations have been shown to have a remarkable rigidity which increases in the inner nuclear region of the lens and has been correlated with the cholesterol (C)/phospholipid (PL) ratio. However, the distribution of these lipids in single lenses had not been determined. Utilizing a new technique for isolating consecutive layers of a human lens, lipid composition and contents of seven pairs of normal lenses from subjects ranging from 54 to 77 years old have been analyzed. It was found that the PL content remains relatively constant at 22-24 micrograms/mg through all but the nuclear 10-15% of the lens dry weight where it drops precipitously to about 7 micrograms/mg. The C distribution is more complex; the C content is at a low level of 14 micrograms/mg in the outer cortical 15-20%, rises to 25 micrograms/mg in the inner cortical 40-60% of the total lens weight, and drops to 12 micrograms/mg upon reaching the nucleus. Thus, the continuous increase in the lens C/PL ratio is due to the increase in C in the cortex and the large decrease in PL in the nucleus. Analyses of phospholipid and fatty acid composition in the different regions of the lens indicate significant differences. However, the abundance of mono-unsaturated fatty acids contributing to the rigidity of the membrane has only minor variation. The lens has a remarkably low overall lipid content of 4% and only 2% in the nuclear region. Calculation of the surface area of the nuclear fiber cell suggests that less than one-third of the membrane is made of PL bilayer. Thus, a mosaic of PL and C patches or some other type of structure involving membrane fusion must be present. Conversion of the % dry weight occupied by the concentric fiber fractions to their location on the lens axis in mm indicates that the nuclear 15% dry weight of the tissue occupies more than 50% of the axial length. This region contains the embryonic lens and the primary lens fibers. Similarly, the metabolically active outer 20% of the dry weight accounts for less than 10% of the visual axial length and contains cells undergoing terminal differentiation. Cataractous lenses have lipid distributions similar to those of the normal lenses suggesting that membrane lipid is either not involved in cataract formation or that the primary insult is localized in an undetectable small number of fiber cells.
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