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- Johansson, Åsa, et al.
(författare)
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Secretory lysosome targeting and induced secretion of human soluble TNF-alpha receptor in murine hematopoietic cells in vivo as a principle for immunoregulation in inflammation and malignancy
- 2009
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Ingår i: Experimental Hematology. - : Elsevier BV. - 0301-472X .- 1873-2399. ; 37:8, s. 969-978
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Systemic administration of immunotherapeutics often gives rise to severe side effects. A local deposition, using secretory lysosomes of hematopoietic cells as vehicles for delivery, can overcome this problem. In the present study, the validity of this concept was investigated using retroviral transduction of the human soluble tumor necrosis factor-alpha receptor 1 (hsTNFR1) into murine bone marrow cells, followed by transfer of the genetically modified cells into irradiated mice. MATERIALS AND METHODS: Bone marrow cells from donor mice were transduced with retroviral vector containing cDNA for hsTNFR1, together with a transmembrane domain and a tyrosine-sorting signal in order to facilitate the endoplasmic reticulum export and to achieve secretory lysosome loading. Expression of hsTNFR1 in recipient mice was investigated using flow cytometry and Western blot. Enzyme-linked immunosorbent assay was used to measure levels of tumor necrosis factor-alpha, hsTNFR1, and murine TNFR1. RESULTS: Stable long-term expression of hsTNFR1 was achieved in transplanted mice. Hematopoietic cells, such as natural killer, T and B cells, and neutrophils contained hsTNFR1. Exposure of lipopolysaccaride (in vivo) or phorbole-myristrate esterase (in vitro) induced significant secretion of hsTNFR1. Release of endogeneous murine sTNFR1 did not differ between cells transduced with hsTNFR1 or an "empty" vector. CONCLUSION: Long-term expression in vivo and inducible secretion of hsTNFR1 in murine hematopoietic cells support the potential use of storage organelles in hematopoietic cells as vehicles for targeting inflamed/malignant sites with therapeutically active agents.
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| 2. |
- Källquist, Linda, et al.
(författare)
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The tetraspanin CD63 is involved in granule targeting of neutrophil elastase.
- 2008
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 112, s. 3444-3454
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Tidskriftsartikel (refereegranskat)abstract
- Targeting mechanisms of neutrophil elastase (NE) and other luminal proteins stored in myeloperoxidase (MPO)-positive secretory lysosomes/primary granules of neutrophils are unknown. These granules contain an integral membrane protein, CD63 with an adaptor protein-3-dependent granule delivery system. Therefore, we hypothesized that CD63 cooperates in granule delivery of the precursor of NE (proNE). Supporting this hypothesis, an association was demonstrated between CD63 and proNE upon coexpression in COS cells. This also involved augmented cellular retention of proNE requiring intact large extracellular loop of CD63. Furthermore, depletion of CD63 in promyelocytic HL-60 cells with RNA interference or a CD63 mutant caused reduction of cellular NE. However, the proNE steady state level was similar to wild type in CD63-depleted clones making it feasible to examine possible effects of CD63 on NE trafficking. Thus, depletion of CD63 led to reduced processing of proNE into mature NE and reduced constitutive secretion. Furthermore, CD63 -depleted cells showed a lack of morphologically normal granules, but contained MPO-positive cytoplasmic vacuoles with a lack of proNE and NE. Collectively, our data suggest that granule proteins may cooperate in targeting; CD63 can be involved in ER or Golgi export, cellular retention and granule targeting of proNE before storage as mature NE.
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| 3. |
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| 4. |
- Tapper, Hans, et al.
(författare)
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Neutrophil elastase sorting involves plasma membrane trafficking requiring the C-terminal propeptide.
- 2006
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 1090-2422 .- 0014-4827. ; 312:18, s. 3471-3484
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Tidskriftsartikel (refereegranskat)abstract
- The primary granules/secretory lysosomes of neutrophils store mature neutrophil elastase (NE) as a luminal protein after proteolytic removal of N-terminal and C-terminal pro-peptides from a proform of NE. The N-terminal pro-peptide prevents premature activation that might be toxic to the cell, but the C-terminal pro-peptide has no defined function. In this study, we investigated the role of the C-terminal pro-peptide in trafficking of NE by expressing, in rat basophilic leukemia (RBL) cells, both wild-type NE and the mutant NE/Delta 248-267, which lacks the C-terminal pro-peptide. Both transfected proteins were found to be targeted to secretory lysosomes. in addition, results from antibody ligation and cell-surface biotinylation indicated that proform of NE was targeted to the plasma membrane, and then subjected to endocytosis. The results were supported by the detection of targeting of the proform to the plasma membrane followed by internalization both in RBL cells and normal granulopoietic precursor cells. Targeting of NE to the plasma membrane required the C-terminal pro-peptide as NE/ Delta 248-267 expressed in RBL cells bypassed plasma membrane trafficking. our results indicate targeting of a population of NE to the plasma membrane and internalization dependent on the C-terminal NE pro-peptide. (c) 2006 Elsevier Inc. All rights reserved.
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