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Pino SC, O'Sullivan-Murphy B, Lidstone EA, Yang C, Lipson KL, Jurczyk A, diIorio P, Brehm MA, Mordes JP, Greiner DL, Rossini AA, Bortell R. CHOP mediates endoplasmic reticulum stress-induced apoptosis in Gimap5-deficient T cells. PLoS One 2009; 4:e5468. [PMID: 19424493 PMCID: PMC2674944 DOI: 10.1371/journal.pone.0005468] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 04/05/2009] [Indexed: 11/25/2022] Open
Abstract
Gimap5 (GTPase of the immunity-associated protein 5) has been linked to the regulation of T cell survival, and polymorphisms in the human GIMAP5 gene associate with autoimmune disorders. The BioBreeding diabetes-prone (BBDP) rat has a mutation in the Gimap5 gene that leads to spontaneous apoptosis of peripheral T cells by an unknown mechanism. Because Gimap5 localizes to the endoplasmic reticulum (ER), we hypothesized that absence of functional Gimap5 protein initiates T cell death through disruptions in ER homeostasis. We observed increases in ER stress-associated chaperones in T cells but not thymocytes or B cells from Gimap5−/− BBDP rats. We then discovered that ER stress-induced apoptotic signaling through C/EBP-homologous protein (CHOP) occurs in Gimap5−/− T cells. Knockdown of CHOP by siRNA protected Gimap5−/− T cells from ER stress-induced apoptosis, thereby identifying a role for this cellular pathway in the T cell lymphopenia of the BBDP rat. These findings indicate a direct relationship between Gimap5 and the maintenance of ER homeostasis in the survival of T cells.
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Affiliation(s)
- Steven C. Pino
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Bryan O'Sullivan-Murphy
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Erich A. Lidstone
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Chaoxing Yang
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Kathryn L. Lipson
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Agata Jurczyk
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Philip diIorio
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Michael A. Brehm
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - John P. Mordes
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Dale L. Greiner
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Aldo A. Rossini
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Rita Bortell
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail:
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Pino SC, O’Sullivan-Murphy B, Lidstone EA, Thornley TB, Jurczyk A, Urano F, Greiner DL, Mordes JP, Rossini AA, Bortell R. Protein kinase C signaling during T cell activation induces the endoplasmic reticulum stress response. Cell Stress Chaperones 2008; 13:421-34. [PMID: 18418732 PMCID: PMC2673927 DOI: 10.1007/s12192-008-0038-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Revised: 02/25/2008] [Accepted: 03/17/2008] [Indexed: 01/27/2023] Open
Abstract
T cell receptor (TCR) ligation (signal one) in the presence of co-stimulation (signal two) results in downstream signals that increase protein production enabling naïve T cells to fully activate and gain effector function. Enhanced production of proteins by a cell requires an increase in endoplasmic reticulum (ER) chaperone expression, which is accomplished through activation of a cellular mechanism known as the ER stress response. The ER stress response is initiated during the cascade of events that occur for the activation of many cells; however, this process has not been comprehensively studied for T cell function. In this study, we used primary T cells and mice circulating TCR transgenic CD8(+) T cells to investigate ER chaperone expression in which TCR signaling was initiated in the presence or absence of co-stimulation. In the presence of both signals, in vitro and in vivo analyses demonstrated induction of the ER stress response, as evidenced by elevated expression of GRP78 and other ER chaperones. Unexpectedly, ER chaperones were also increased in T cells exposed only to signal one, a treatment known to cause T cells to enter the 'nonresponsive' states of anergy and tolerance. Treatment of T cells with an inhibitor to protein kinase C (PKC), a serine/threonine protein kinase found downstream of TCR signaling, indicated PKC is involved in the induction of the ER stress response during the T cell activation process, thus revealing a previously unknown role for this signaling protein in T cells. Collectively, these data suggest that induction of the ER stress response through PKC signaling is an important component for the preparation of a T cell response to antigen.
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Affiliation(s)
- Steven C. Pino
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | | | - Erich A. Lidstone
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Thomas B. Thornley
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Agata Jurczyk
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Fumihiko Urano
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, MA 01605 USA
- Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Dale L. Greiner
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - John P. Mordes
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Aldo A. Rossini
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605 USA
- Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Rita Bortell
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605 USA
- Diabetes Division, Suite 218, 373 Plantation Street, Worcester, MA 01605 USA
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Morrison AR, Moss J, Stevens LA, Evans JE, Farrell C, Merithew E, Lambright DG, Greiner DL, Mordes JP, Rossini AA, Bortell R. ART2, a T cell surface mono-ADP-ribosyltransferase, generates extracellular poly(ADP-ribose). J Biol Chem 2006; 281:33363-72. [PMID: 16931513 DOI: 10.1074/jbc.m607259200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
NAD functions in multiple aspects of cellular metabolism and signaling through enzymes that covalently transfer ADP-ribose from NAD to acceptor proteins, thereby altering their function. NAD is a substrate for two enzyme families, mono-ADP-ribosyltransferases (mARTs) and poly(ADP-ribose) polymerases (PARPs), that covalently transfer an ADP-ribose monomer or polymer, respectively, to acceptor proteins. ART2, a mART, is a phenotypic marker of immunoregulatory cells found on the surface of T lymphocytes, including intestinal intraepithelial lymphocytes (IELs). We have shown that the auto-ADP-ribosylation of the ART2.2 allelic protein is multimeric. Our backbone structural alignment of ART2 (two alleles of the rat art2 gene have been reported, for simplicity, the ART2.2 protein investigated in this study will be referred to as ART2) and PARP suggested that multimeric auto-ADP-ribosylation of ART2 may represent an ADP-ribose polymer, rather than multiple sites of mono-ADP-ribosylation. To investigate this, we used highly purified recombinant ART2 and demonstrated that ART2 catalyzes the formation of an ADP-ribose polymer by sequencing gel and by HPLC and MS/MS mass spectrometry identification of PR-AMP, a breakdown product specific to poly(ADP-ribose). Furthermore, we identified the site of ADP-ribose polymer attachment on ART2 as Arg-185, an arginine in a crucial loop of its catalytic core. We found that endogenous ART2 on IELs undergoes multimeric auto-ADP-ribosylation more efficiently than ART2 on peripheral T cells, suggesting that these distinct lymphocyte populations differ in their ART2 surface topology. Furthermore, ART2.2 IELs are more resistant to NAD-induced cell death than ART2.1 IELs that do not have multimeric auto-ADP-ribosylation activity. The data suggest that capability of polymerizing ADP-ribose may not be unique to PARPs and that poly(ADP-ribosylation), an established nuclear activity, may occur extracellularly and modulate cell function.
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Affiliation(s)
- Alan R Morrison
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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Pandarpurkar M, Wilson-Fritch L, Corvera S, Markholst H, Hornum L, Greiner DL, Mordes JP, Rossini AA, Bortell R. Ian4 is required for mitochondrial integrity and T cell survival. Proc Natl Acad Sci U S A 2003; 100:10382-7. [PMID: 12930893 PMCID: PMC193570 DOI: 10.1073/pnas.1832170100] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Apoptosis is a regulated cell death program controlled by extrinsic and intrinsic signaling pathways. The intrinsic pathway involves stress signals that activate pro-apoptotic members of the Bcl-2 family, inducing permeabilization of mitochondria and release of apoptogenic factors. These proteins localize to the outer mitochondrial membrane. Ian4, a mitochondrial outer membrane protein with GTP-binding activity, is normally present in thymocytes, T cells, and B cells. We and others have recently discovered that a mutation in the rat Ian4 gene results in severe T cell lymphopenia that is associated with the expression of autoimmune diabetes. The mechanism by which Ian4 controls T cell homeostasis is unknown. Here we show that the absence of Ian4 in T cells causes mitochondrial dysfunction, increased mitochondrial levels of stress-inducible chaperonins and a leucine-rich protein, and T cell-specific spontaneous apoptosis. T cell activation and caspase 8 inhibition both prevented apoptosis, whereas transfection of T cells with Ian4-specific small interfering RNA recapitulated the apoptotic phenotype. The findings establish Ian4 as a tissue-specific regulator of mitochondrial integrity.
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Affiliation(s)
- Malini Pandarpurkar
- Department of Medicine and Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Suite 218, Worcester, MA 01605, USA
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Stevens LA, Bourgeois C, Bortell R, Moss J. Regulatory role of arginine 204 in the catalytic activity of rat alloantigens ART2a and ART2b. J Biol Chem 2003; 278:19591-6. [PMID: 12649291 DOI: 10.1074/jbc.m210364200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ART2a (RT6.1) and ART2b (RT6.2) are NAD glycohydrolases (NADases) that are linked to T lymphocytes by glycosylphosphatidylinositol anchors. Although both mature proteins possess three conserved regions (I, II, III) that form the NAD-binding site and differ by only ten amino acids, only ART2b is auto-ADP-ribosylated and only ART2a is glycosylated. To investigate the structural basis for these differences, wild-type and mutant ART2a and ART2b were expressed in rat mammary adenocarcinoma (NMU) cells and released with phosphatidylinositol-specific phospholipase C. All mutants were immunoreactive NADases. Arginine 204 (Arg204), NH2-terminal to essential glutamate 209 in Region III, is found in ART2b, but not ART2a. Replacement of Arg204 in ART2b with lysine, tyrosine, or glutamate abolished auto-ADP-ribosylation. Unlike wild-type ART2a, ART2a(Y204R) was auto-ADP-ribosylated. The tryptophan mutant ART2b(R204W) was auto-ADP-ribosylated and exhibited enhanced NADase activity. Incubation with NAD and auto-ADP-ribosylation decreased the NADase activities of wild-type ART2b and ART2b (R204W), whereas activity of ART2b(R204K), which is not auto-modified, was unchanged by NAD. Facilitation of auto-ADP-ribosylation by tryptophan 204 suggests that the hydrophobic amino acid mimics an ADP-ribosylated arginine. Thus, Arg204 in ART2b serves as a regulatory switch whose presence is required for additional auto-ADP-ribosylation and regulation of catalytic activity.
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Affiliation(s)
- Linda A Stevens
- Pulmonary-Critical Care Medicine Branch, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-1590, USA.
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Adriouch S, Ohlrogge W, Haag F, Koch-Nolte F, Seman M. Rapid induction of naive T cell apoptosis by ecto-nicotinamide adenine dinucleotide: requirement for mono(ADP-ribosyl)transferase 2 and a downstream effector. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:196-203. [PMID: 11418649 DOI: 10.4049/jimmunol.167.1.196] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Lymphocytes express a number of NAD-metabolizing ectoenzymes, including mono(ADP-ribosyl)transferases (ART) and ADP ribosylcyclases. These enzymes may regulate lymphocyte functions following the release of NAD in injured or inflammatory tissues We report here that extracellular NAD induces apoptosis in BALB/c splenic T cells with an IC(50) of 3-5 microM. Annexin V staining of cells was observed already 10 min after treatment with NAD in the absence of any additional signal. Removal of GPI-anchored cell surface proteins by phosphatidylinositol-specific phospholipase C treatment rendered cells resistant to NAD-mediated apoptosis. RT-PCR analyses revealed that resting BALB/c T cells expressed the genes for GPI-anchored ART2.1 and ART2.2 but not ART1. ART2-specific antisera blocked radiolabeling of cell surface proteins with both [(32)P]NAD and NAD-mediated apoptosis. Further analyses revealed that natural knockout mice for Art2.a (C57BL/6) or Art2.b (NZW) were resistant to NAD-mediated apoptosis. Labeling with [(32)P]NAD revealed strong cell surface ART activity on T cells of C57BL/6 and little if any activity on cells of NZW mice. T cells of (C57BL/6 x NZW)F(1) animals showed strong cell surface ART activity and were very sensitive to NAD-induced apoptosis. As in BALB/c T cells, ART2-specific antisera blocked cell surface ART activity and apoptosis in (C57BL/6 x NZW)F(1) T cells. The fact that T cells of F(1) animals are sensitive to rapid NAD-induced apoptosis suggests that this effect requires the complementation of (at least) two genetic components. We propose that one of these is cell surface ART2.2 activity (defective in the NZW parent), the other a downstream effector of ADP-ribosylation (defective in the C57BL/6 parent).
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Affiliation(s)
- S Adriouch
- Laboratoire d'Immunodifferenciation, Université Denis-Diderot Paris 7, Paris, France
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Bortel R, Waite DJ, Whalen BJ, Todd D, Leif JH, Lesma E, Moss J, Mordes JP, Rossini AA, Greiner DL. Levels of Art2+ cells but not soluble Art2 protein correlate with expression of autoimmune diabetes in the BB rat. Autoimmunity 2001; 33:199-211. [PMID: 11683379 DOI: 10.3109/08916930109008047] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ART2a and ART2b are isoenzymes expressed on the surface of mature T cells and intraepithelial lymphocytes (IELs) in the rat. They exhibit both adenosine diphosphoribosyltransferase and nicotine adenine dinucleotide (NAD) glycohydrolase activities, and both can generate a transmembrane signal that modulates T cell activation. The presence or absence of ART2+ T cells modulates the expression of autoimmune diabetes in the BB rat. ART2 also circulates in a soluble form whose function is unknown. We tested the hypothesis that circulating ART2 protein regulates the expression of autoimmunity. We compared the kinetics, regulation, and source of soluble ART2 in normal rats and in rats with autoimmune diabetes. Basal levels of soluble ART2 varied greatly among strains of rats and were lowest in the diabetes-prone BB (BBDP/Wor) rat. In diabetes-resistant BB (BBDR/Wor) rats, administration of anti-ART2a antibody, which is known to induce diabetes, resulted in transient clearing of soluble ART2a that was followed rapidly by a rebound increase. Repeated treatment of BBDR/Wor rats with anti-ART2a antibody resulted in sustained supraphysiologic levels of soluble ART2a. Although the number of peripheral ART2a+ T cells is known to correlate with the expression of diabetes in BBDR/Wor rats, the level of soluble ART2a protein did not. The source of the soluble ART2 protein in the rat appeared to be the gut. The results suggest that ART2+ T cells and soluble ART2 protein may subserve different immunomodulatory functions.
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Affiliation(s)
- R Bortel
- Department of Medicine, University of Massachusetts Medical Center, Worcester 01655, USA.
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Okazaki IJ, Moss J. Characterization of glycosylphosphatidylinositiol-anchored, secreted, and intracellular vertebrate mono-ADP-ribosyltransferases. Annu Rev Nutr 1999; 19:485-509. [PMID: 10448534 DOI: 10.1146/annurev.nutr.19.1.485] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mono-ADP-ribosylation is a posttranslational modification of proteins in which the ADP-ribose moiety of nicotinamide adenine dinucleotide is transferred to an acceptor amino acid. Five mammalian ADP-ribosyltransferases (ART1--ART5) have been cloned and expression is restricted to tissues such as cardiac and skeletal muscle, leukocytes, brain, and testis. ART1 and ART2 are glycosylphosphatidylinositol (GPI)-anchored ectoenzymes. ART5 appears not to be GPI-linked and may be secreted. In skeletal muscle and lymphocytes, ART1 modifies specific members of the integrin family of adhesion molecules, suggesting that ADP-ribosylation affects cell-matrix or cell-cell interactions. In lymphocytes, ADP-ribosylation of surface proteins is associated with changes in p56lck tyrosine kinase-mediated signaling. The catalytic sites of bacterial toxins and vertebrate transferases have conserved structural features, consistent with a common reaction mechanism. ADP-ribosylation can be reversed by ADP-ribosylarginine hydrolases, resulting in the regeneration of free arginine. Thus, an ADP-ribosylation cycle may play a regulatory role in vertebrate tissues.
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Affiliation(s)
- I J Okazaki
- Pulmonary-Critical Care Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-1434, USA.
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