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Histidyl-tRNA synthetase and asparaginyl-tRNA synthetase, autoantigens in myositis, activate chemokine receptors on T lymphocytes and immature dendritic cells.

Howard OM, Dong HF, Yang D, Raben N, Nagaraju K, Rosen A, Casciola-Rosen L, Härtlein M, Kron M, Yang D, Yiadom K, Dwivedi S, Plotz PH, Oppenheim JJ - J. Exp. Med. (2002)

Bottom Line: Seryl-tRNA synthetase induced migration of CCR3-transfected cells but not iDCs.Nonautoantigenic aspartyl-tRNA and lysyl-tRNA synthetases were not chemotactic.Therefore, the selection of a self-molecule as a target for an autoantibody response may be a consequence of the proinflammatory properties of the molecule itself.

View Article: PubMed Central - PubMed

Affiliation: National Cancer Institute, Center for Cancer Research, Laboratory of Molecular Immunoregulation, Frederick, MD 21702, USA. howardz@mail.ncifcrf.gov

ABSTRACT
Autoantibodies to histidyl-tRNA synthetase (HisRS) or to alanyl-, asparaginyl-, glycyl-, isoleucyl-, or threonyl-tRNA synthetase occur in approximately 25% of patients with polymyositis or dermatomyositis. We tested the ability of several aminoacyl-tRNA synthetases to induce leukocyte migration. HisRS induced CD4(+) and CD8(+) lymphocytes, interleukin (IL)-2-activated monocytes, and immature dendritic cells (iDCs) to migrate, but not neutrophils, mature DCs, or unstimulated monocytes. An NH(2)-terminal domain, 1-48 HisRS, was chemotactic for lymphocytes and activated monocytes, whereas a deletion mutant, HisRS-M, was inactive. HisRS selectively activated CC chemokine receptor (CCR)5-transfected HEK-293 cells, inducing migration by interacting with extracellular domain three. Furthermore, monoclonal anti-CCR5 blocked HisRS-induced chemotaxis and conversely, HisRS blocked anti-CCR5 binding. Asparaginyl-tRNA synthetase induced migration of lymphocytes, activated monocytes, iDCs, and CCR3-transfected HEK-293 cells. Seryl-tRNA synthetase induced migration of CCR3-transfected cells but not iDCs. Nonautoantigenic aspartyl-tRNA and lysyl-tRNA synthetases were not chemotactic. Thus, autoantigenic aminoacyl-tRNA synthetases, perhaps liberated from damaged muscle cells, may perpetuate the development of myositis by recruiting mononuclear cells that induce innate and adaptive immune responses. Therefore, the selection of a self-molecule as a target for an autoantibody response may be a consequence of the proinflammatory properties of the molecule itself.

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Primary lymphocytes, CD4+ and CD8+ lymphocytes migrate to HisRS and 1–48 HRS but neutrophils do not. Recombinant HisRS (HRS), a synthetic peptide corresponding to the first 48 amino acids of HisRS (1–48 HRS), or a deletion mutant form of HisRS that lacks the first 60 amino acids (M-HRS) were placed in the lower wells of a micro-Boyden chamber. The concentrations of various HisRS forms are shown on the x-axis while the mean number of cells in a 200× field ± standard deviation is shown on the y-axis. Binding medium indicates background, while CXCL-12 (SDF-1) or fMLP was used as a positive control. Each condition was performed in triplicate. Each assay was performed a minimum of three times. Unpaired Student t tests were performed comparing the number of migrating cells in the binding medium vs. the number of migrating cells in individual chemoattractant concentrations. * denotes a P value ≤0.0001.
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fig1: Primary lymphocytes, CD4+ and CD8+ lymphocytes migrate to HisRS and 1–48 HRS but neutrophils do not. Recombinant HisRS (HRS), a synthetic peptide corresponding to the first 48 amino acids of HisRS (1–48 HRS), or a deletion mutant form of HisRS that lacks the first 60 amino acids (M-HRS) were placed in the lower wells of a micro-Boyden chamber. The concentrations of various HisRS forms are shown on the x-axis while the mean number of cells in a 200× field ± standard deviation is shown on the y-axis. Binding medium indicates background, while CXCL-12 (SDF-1) or fMLP was used as a positive control. Each condition was performed in triplicate. Each assay was performed a minimum of three times. Unpaired Student t tests were performed comparing the number of migrating cells in the binding medium vs. the number of migrating cells in individual chemoattractant concentrations. * denotes a P value ≤0.0001.

Mentions: We began our studies by evaluating the ability of normal primary human leukocytes isolated from apheresis samples to migrate to either HisRS or AsnRS, known targets of autoantibodies in myositis, and SerRS, LysRS, and Asp-RS, which are not. In addition, we tested a recombinant NH2-terminal deletion mutant of HisRS, HisRS-M, and a synthetic peptide (1–48 HisRS). Neither primary monocytes nor neutrophils responded chemotactically to HisRS, HisRS-M, 1–48 HisRS, AsnRS, SerRS, AspRS, or LysRS. However, percoll-isolated unfractionated lymphocytes and CD4+ and CD8+ lymphocyte subsets were chemoattracted by HisRS and 1–48 HisRS. No leukocyte subset was chemoattracted by HisRS-M. As can be seen in Fig. 1 , the maximum chemotactic activity for HisRS was observed at 10 ng/ml (0.17 nM) for the unfractionated lymphocytes (C.I. = 2.2, P < 0.0001) and CD4+ lymphocytes (C.I. = 2.7, P < 0.001). The maximal chemotactic activity was at 50 ng/ml for CD8+ lymphocytes. The maximum chemotactic activity for 1–48 HisRS was obtained with 100 ng/ml (18.9 nM) for unfractionated lymphocytes (C.I. = 2.3, P < 0.0001) and CD4+ lymphocytes (C.I. = 2.7, P < 0.0001). Again, there was a slight shift in the peak dose for CD8+ lymphocytes. Thus, HisRS is a more potent chemoattractant than the 1–48 HisRS peptide, but both are efficacious. Unfractionated lymphocytes were not chemoattracted to AsnRS (C.I. = 1.4, P > 0.05, n = 3) or SerRS (C.I. = 1.7, P ≤ 0.05, n = 3).


Histidyl-tRNA synthetase and asparaginyl-tRNA synthetase, autoantigens in myositis, activate chemokine receptors on T lymphocytes and immature dendritic cells.

Howard OM, Dong HF, Yang D, Raben N, Nagaraju K, Rosen A, Casciola-Rosen L, Härtlein M, Kron M, Yang D, Yiadom K, Dwivedi S, Plotz PH, Oppenheim JJ - J. Exp. Med. (2002)

Primary lymphocytes, CD4+ and CD8+ lymphocytes migrate to HisRS and 1–48 HRS but neutrophils do not. Recombinant HisRS (HRS), a synthetic peptide corresponding to the first 48 amino acids of HisRS (1–48 HRS), or a deletion mutant form of HisRS that lacks the first 60 amino acids (M-HRS) were placed in the lower wells of a micro-Boyden chamber. The concentrations of various HisRS forms are shown on the x-axis while the mean number of cells in a 200× field ± standard deviation is shown on the y-axis. Binding medium indicates background, while CXCL-12 (SDF-1) or fMLP was used as a positive control. Each condition was performed in triplicate. Each assay was performed a minimum of three times. Unpaired Student t tests were performed comparing the number of migrating cells in the binding medium vs. the number of migrating cells in individual chemoattractant concentrations. * denotes a P value ≤0.0001.
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Related In: Results  -  Collection

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fig1: Primary lymphocytes, CD4+ and CD8+ lymphocytes migrate to HisRS and 1–48 HRS but neutrophils do not. Recombinant HisRS (HRS), a synthetic peptide corresponding to the first 48 amino acids of HisRS (1–48 HRS), or a deletion mutant form of HisRS that lacks the first 60 amino acids (M-HRS) were placed in the lower wells of a micro-Boyden chamber. The concentrations of various HisRS forms are shown on the x-axis while the mean number of cells in a 200× field ± standard deviation is shown on the y-axis. Binding medium indicates background, while CXCL-12 (SDF-1) or fMLP was used as a positive control. Each condition was performed in triplicate. Each assay was performed a minimum of three times. Unpaired Student t tests were performed comparing the number of migrating cells in the binding medium vs. the number of migrating cells in individual chemoattractant concentrations. * denotes a P value ≤0.0001.
Mentions: We began our studies by evaluating the ability of normal primary human leukocytes isolated from apheresis samples to migrate to either HisRS or AsnRS, known targets of autoantibodies in myositis, and SerRS, LysRS, and Asp-RS, which are not. In addition, we tested a recombinant NH2-terminal deletion mutant of HisRS, HisRS-M, and a synthetic peptide (1–48 HisRS). Neither primary monocytes nor neutrophils responded chemotactically to HisRS, HisRS-M, 1–48 HisRS, AsnRS, SerRS, AspRS, or LysRS. However, percoll-isolated unfractionated lymphocytes and CD4+ and CD8+ lymphocyte subsets were chemoattracted by HisRS and 1–48 HisRS. No leukocyte subset was chemoattracted by HisRS-M. As can be seen in Fig. 1 , the maximum chemotactic activity for HisRS was observed at 10 ng/ml (0.17 nM) for the unfractionated lymphocytes (C.I. = 2.2, P < 0.0001) and CD4+ lymphocytes (C.I. = 2.7, P < 0.001). The maximal chemotactic activity was at 50 ng/ml for CD8+ lymphocytes. The maximum chemotactic activity for 1–48 HisRS was obtained with 100 ng/ml (18.9 nM) for unfractionated lymphocytes (C.I. = 2.3, P < 0.0001) and CD4+ lymphocytes (C.I. = 2.7, P < 0.0001). Again, there was a slight shift in the peak dose for CD8+ lymphocytes. Thus, HisRS is a more potent chemoattractant than the 1–48 HisRS peptide, but both are efficacious. Unfractionated lymphocytes were not chemoattracted to AsnRS (C.I. = 1.4, P > 0.05, n = 3) or SerRS (C.I. = 1.7, P ≤ 0.05, n = 3).

Bottom Line: Seryl-tRNA synthetase induced migration of CCR3-transfected cells but not iDCs.Nonautoantigenic aspartyl-tRNA and lysyl-tRNA synthetases were not chemotactic.Therefore, the selection of a self-molecule as a target for an autoantibody response may be a consequence of the proinflammatory properties of the molecule itself.

View Article: PubMed Central - PubMed

Affiliation: National Cancer Institute, Center for Cancer Research, Laboratory of Molecular Immunoregulation, Frederick, MD 21702, USA. howardz@mail.ncifcrf.gov

ABSTRACT
Autoantibodies to histidyl-tRNA synthetase (HisRS) or to alanyl-, asparaginyl-, glycyl-, isoleucyl-, or threonyl-tRNA synthetase occur in approximately 25% of patients with polymyositis or dermatomyositis. We tested the ability of several aminoacyl-tRNA synthetases to induce leukocyte migration. HisRS induced CD4(+) and CD8(+) lymphocytes, interleukin (IL)-2-activated monocytes, and immature dendritic cells (iDCs) to migrate, but not neutrophils, mature DCs, or unstimulated monocytes. An NH(2)-terminal domain, 1-48 HisRS, was chemotactic for lymphocytes and activated monocytes, whereas a deletion mutant, HisRS-M, was inactive. HisRS selectively activated CC chemokine receptor (CCR)5-transfected HEK-293 cells, inducing migration by interacting with extracellular domain three. Furthermore, monoclonal anti-CCR5 blocked HisRS-induced chemotaxis and conversely, HisRS blocked anti-CCR5 binding. Asparaginyl-tRNA synthetase induced migration of lymphocytes, activated monocytes, iDCs, and CCR3-transfected HEK-293 cells. Seryl-tRNA synthetase induced migration of CCR3-transfected cells but not iDCs. Nonautoantigenic aspartyl-tRNA and lysyl-tRNA synthetases were not chemotactic. Thus, autoantigenic aminoacyl-tRNA synthetases, perhaps liberated from damaged muscle cells, may perpetuate the development of myositis by recruiting mononuclear cells that induce innate and adaptive immune responses. Therefore, the selection of a self-molecule as a target for an autoantibody response may be a consequence of the proinflammatory properties of the molecule itself.

Show MeSH
Related in: MedlinePlus