Platelet and red blood cell phagocytosis kinetics are differentially controlled by phosphatase activity within mononuclear cells
(2007) In Transfusion 47(11). p.2161-2168- Abstract
BACKGROUND: Anti-D treatment is effective in increasing platelet (PLT) counts in patients with autoimmune thrombocytopenic purpura (AITP); however, the exact mechanism of action is unknown. Previous results have suggested that anti-D-coated red blood cells (RBCs) affect reticuloendothelial system phagocytosis by stimulating agents (e.g., reactive oxygen species) that alter signaling pathways within the phagocyte. To address this, a flow cytometric assay was used to compare the kinetics and signaling pathways responsible for opsonized PLT and RBC phagocytosis. STUDY DESIGN AND METHODS: Human RBCs or PLTs were labeled with the fluorescent dye CM-Green, opsonized with Rh immune globulin or anti-MHC, respectively, and incubated with THP-1... (More)
BACKGROUND: Anti-D treatment is effective in increasing platelet (PLT) counts in patients with autoimmune thrombocytopenic purpura (AITP); however, the exact mechanism of action is unknown. Previous results have suggested that anti-D-coated red blood cells (RBCs) affect reticuloendothelial system phagocytosis by stimulating agents (e.g., reactive oxygen species) that alter signaling pathways within the phagocyte. To address this, a flow cytometric assay was used to compare the kinetics and signaling pathways responsible for opsonized PLT and RBC phagocytosis. STUDY DESIGN AND METHODS: Human RBCs or PLTs were labeled with the fluorescent dye CM-Green, opsonized with Rh immune globulin or anti-MHC, respectively, and incubated with THP-1 monocytes with or without signal transduction inhibitors and intracellular fluorescence was analyzed. RESULTS: Compared with opsonized PLTs, phagocytosis of opsonized RBCs was significantly slower (p < 0.0001) and, within 2 hours, induced a state of phagocytic refractoriness; resting the mononuclear cells (MNCs) for up to 24 hours did not rescue their ability to further mediate PLT phagocytosis. Inhibitors of phosphatidylinositol 3-kinase (wortmannin, LY294002, myricetin, and quercetin), protein kinase C (staurosporine), and Syk kinase (piceatannol) inhibited both opsonized RBC and opsonized PLT phagocytosis. In contrast, opsonized RBC phagocytosis was significantly (p < 0.0001) enhanced by the tyrosine phosphatase inhibitor phenyl arsine oxide, whereas PLT phagocytosis was significantly reduced (p < 0.0001). Of interest, phosphatase inhibition during opsonized RBC phagocytosis induced a longer (48 hr) phagocytic refractoriness period in the MNCs. CONCLUSION: These results suggest that the early kinetics and signaling events related to phosphatase activity regulate how mononuclear phagocytes engulf opsonized RBCs and induce phagocytic refractoriness for further PLT phagocytosis.
(Less)
- author
- Aslam, Rukhsana ; Kim, Michael ; Speck, Edwin R. ; Seetanah, Arjuna Contram ; Molinski, Steven ; Freedman, John and Semple, John W. LU
- publishing date
- 2007-11-01
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Transfusion
- volume
- 47
- issue
- 11
- pages
- 2161 - 2168
- publisher
- Wiley-Blackwell
- external identifiers
-
- pmid:17958546
- scopus:35448947923
- ISSN
- 0041-1132
- DOI
- 10.1111/j.1537-2995.2007.01441.x
- language
- English
- LU publication?
- no
- id
- d52eea24-06a6-429d-9437-364a923b6820
- date added to LUP
- 2019-12-03 10:18:31
- date last changed
- 2024-01-02 01:03:48
@article{d52eea24-06a6-429d-9437-364a923b6820,
abstract = {{<p>BACKGROUND: Anti-D treatment is effective in increasing platelet (PLT) counts in patients with autoimmune thrombocytopenic purpura (AITP); however, the exact mechanism of action is unknown. Previous results have suggested that anti-D-coated red blood cells (RBCs) affect reticuloendothelial system phagocytosis by stimulating agents (e.g., reactive oxygen species) that alter signaling pathways within the phagocyte. To address this, a flow cytometric assay was used to compare the kinetics and signaling pathways responsible for opsonized PLT and RBC phagocytosis. STUDY DESIGN AND METHODS: Human RBCs or PLTs were labeled with the fluorescent dye CM-Green, opsonized with Rh immune globulin or anti-MHC, respectively, and incubated with THP-1 monocytes with or without signal transduction inhibitors and intracellular fluorescence was analyzed. RESULTS: Compared with opsonized PLTs, phagocytosis of opsonized RBCs was significantly slower (p < 0.0001) and, within 2 hours, induced a state of phagocytic refractoriness; resting the mononuclear cells (MNCs) for up to 24 hours did not rescue their ability to further mediate PLT phagocytosis. Inhibitors of phosphatidylinositol 3-kinase (wortmannin, LY294002, myricetin, and quercetin), protein kinase C (staurosporine), and Syk kinase (piceatannol) inhibited both opsonized RBC and opsonized PLT phagocytosis. In contrast, opsonized RBC phagocytosis was significantly (p < 0.0001) enhanced by the tyrosine phosphatase inhibitor phenyl arsine oxide, whereas PLT phagocytosis was significantly reduced (p < 0.0001). Of interest, phosphatase inhibition during opsonized RBC phagocytosis induced a longer (48 hr) phagocytic refractoriness period in the MNCs. CONCLUSION: These results suggest that the early kinetics and signaling events related to phosphatase activity regulate how mononuclear phagocytes engulf opsonized RBCs and induce phagocytic refractoriness for further PLT phagocytosis.</p>}},
author = {{Aslam, Rukhsana and Kim, Michael and Speck, Edwin R. and Seetanah, Arjuna Contram and Molinski, Steven and Freedman, John and Semple, John W.}},
issn = {{0041-1132}},
language = {{eng}},
month = {{11}},
number = {{11}},
pages = {{2161--2168}},
publisher = {{Wiley-Blackwell}},
series = {{Transfusion}},
title = {{Platelet and red blood cell phagocytosis kinetics are differentially controlled by phosphatase activity within mononuclear cells}},
url = {{http://dx.doi.org/10.1111/j.1537-2995.2007.01441.x}},
doi = {{10.1111/j.1537-2995.2007.01441.x}},
volume = {{47}},
year = {{2007}},
}