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PARP-2 deficiency affects the survival of CD4+CD8+ double-positive thymocytes.

ABSTRACT: Poly-(ADP-ribose) polymerase-2 (PARP-2) belongs to a large family of enzymes that synthesize and transfer ADP-ribose polymers to acceptor proteins, modifying their functional properties. PARP-2-deficient (Parp-2-/-) cells, similar to Parp-1-/- cells, are sensitive to both ionizing radiation and alkylating agents. Here we show that inactivation of mouse Parp-2, but not Parp-1, produced a two-fold reduction in CD4+CD8+ double-positive (DP) thymocytes associated with decreased DP cell survival. Microarray analyses revealed increased expression of the proapoptotic Bcl-2 family member Noxa in Parp-2-/- DP thymocytes compared to littermate controls. In addition, DP thymocytes from Parp-2-/- have a reduced expression of T-cell receptor (TCR)alpha and a skewed repertoire of TCRalpha toward the 5' Jalpha segments. Our results show that in the absence of PARP-2, the survival of DP thymocytes undergoing TCRalpha recombination is compromised despite normal amounts of Bcl-xL. These data suggest a novel role for PARP-2 as an important mediator of T-cell survival during thymopoiesis by preventing the activation of DNA damage-dependent apoptotic response during the multiple rounds of TCRalpha rearrangements preceding a positively selected TCR.

SUBMITTER: Yelamos J

PROVIDER: S-EPMC1570435 | biostudies-literature | 2006 Sep

REPOSITORIES: biostudies-literature

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PARP-2 deficiency affects the survival of CD4+CD8+ double-positive thymocytes.

Yélamos José J Monreal Yolanda Y Saenz Luis L Aguado Enrique E Schreiber Valérie V Mota Rubén R Fuente Teodomiro T Minguela Alfredo A Parrilla Pascual P de Murcia Gilbert G Almarza Elena E Aparicio Pedro P Ménissier-de Murcia Josiane J

The EMBO journal 20060831 18

Poly-(ADP-ribose) polymerase-2 (PARP-2) belongs to a large family of enzymes that synthesize and transfer ADP-ribose polymers to acceptor proteins, modifying their functional properties. PARP-2-deficient (Parp-2-/-) cells, similar to Parp-1-/- cells, are sensitive to both ionizing radiation and alkylating agents. Here we show that inactivation of mouse Parp-2, but not Parp-1, produced a two-fold reduction in CD4+CD8+ double-positive (DP) thymocytes associated with decreased DP cell survival. Mic ...[more]

PMID: 16946705

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Project description:Glucocorticoids play a role in regulation of T lymphocytes homeostasis and development. In particular, glucocorticoid treatment induces massive apoptosis of CD4+CD8+ double positive (DP) thymocytes. This effect is due to many mechanisms, mainly driven by modulation of gene transcription. To find out which genes are modulated, we analyzed DP thymocytes treated for 3 hours with dexamethasone or medium alone, by global gene expression profiling using the Affymetrix technology (MGU74Av2 GeneChip). The data were analyzed with MAS 5.0 imposing a cut off of 1.7 fold in up regulation and 1.35 fold in down regulation. To further filter results we also used the statistical software, SAM (d 0.88 see figure 1s in supplementary data of the above cited manuscript). Results indicate modulation of 156 genes, also confirmed by either RNAse protection assay or Real Time PCR. For data mining we also used Go Miner to explore the Gene Ontology data bank (see tables 1-3 of the above cited manuscript). The overall results demonstrated that dexamethasone caused the down-regulation of genes promoting survival of DP thymocytes (e.g. Notch1, Socs1 and Id3) or the modulation of genes activating cell death through the ceramide pathway (Ugcg, Sgpp1, Degs1 and Gpr65) or through the mithocondrial machinery. Among the latter, there are Bcl-2 family members (Bim, Bfl-1, Bcl-xL and Bcl-xbeta), genes involved in the control of redox status (thioredoxin reductase, TXNIP and idh2) and genes belonging to Tis11 family which are involved in mRNA stability. Our study suggests that dexamethasone treatment of DP thymocytes modulates several genes belonging to apoptosis-related systems that can contribute to their apoptosis. Experiment Overall Design: Thymi from 4 week old C3H/HeN mice were teased in culture medium, CD4+CD8+ double positive (DP) thymocytes were sorted with microbeads Miltenyi Biotech methods and were plated in 6 well plates with 3 ml of the culture medium at a concentration of 5.0E+06 cell/ml together with 1E-07 M Dexamethasone or a corresponding volume of PBS. DP thymocytes were kept at 37Â°C, 5% CO2 in a humidified atmosphere for 3 hours. Total RNA was extracted and analyzed. We used 2 technical replicate-extracts.

Project description:BACKGROUND: CD4+/CD8+ double positive (DP) T cells have been described in healthy individuals as well as in patients with autoimmune and chronic infectious diseases. In chronic viral infections, this cell subset has effector memory phenotype and displays antigen specificity. No previous studies of double positive T cells in parasite infections have been carried out. METHODOLOGY/PRINCIPAL FINDINGS: Seventeen chronic chagasic patients (7 asymptomatic and 10 symptomatic) and 24 non-infected donors, including 12 healthy and 12 with non-chagasic cardiomyopathy donors were analyzed. Peripheral blood was stained for CD3, CD4, CD8, HLA-DR and CD38, and lymphocytes for intracellular perforin. Antigen specificity was assessed using HLA*A2 tetramers loaded with T. cruzi K1 or influenza virus epitopes. Surface expression of CD107 and intracellular IFN-? production were determined in K1-specific DP T cells from 11 chagasic donors. Heart tissue from a chronic chagasic patient was stained for both CD8 and CD4 by immunochemistry. Chagasic patients showed higher frequencies of DP T cells (2.1% ± 0.9) compared with healthy (1.1% ± 0.5) and non-chagasic cardiomyopathy (1.2% ± 0.4) donors. DP T cells from Chagasic patients also expressed more HLA-DR, CD38 and perforin and had higher frequencies of T. cruzi K1-specific cells. IFN-? production in K1-specific cells was higher in asymptomatic patients after polyclonal stimulation, while these cells tended to degranulate more in symptomatic donors. Immunochemistry revealed that double positive T cells infiltrate the cardiac tissue of a chagasic donor. CONCLUSIONS: Chagasic patients have higher percentages of circulating double positive T cells expressing activation markers, potential effector molecules and greater class I antigenic specificity against T. cruzi. Although K1 tetramer positive DP T cell produced little IFN-?, they displayed degranulation activity that was increased in symptomatic patients. Moreover, K1-specific DP T cells can migrate to the heart tissue.

Dataset Information

PARP-2 deficiency affects the survival of CD4+CD8+ double-positive thymocytes.

Publications

PARP-2 deficiency affects the survival of CD4+CD8+ double-positive thymocytes.

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