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Hearn JI, Green TN, Chopra M, Nursalim YNS, Ladvanszky L, Knowlton N, Blenkiron C, Poulsen RC, Singleton DC, Bohlander SK, Kalev-Zylinska ML. N-Methyl-D-Aspartate Receptor Hypofunction in Meg-01 Cells Reveals a Role for Intracellular Calcium Homeostasis in Balancing Megakaryocytic-Erythroid Differentiation. Thromb Haemost 2020; 120:671-686. [PMID: 32289863 PMCID: PMC7286128 DOI: 10.1055/s-0040-1708483] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The release of calcium ions (Ca
2+
) from the endoplasmic reticulum (ER) and related store-operated calcium entry (SOCE) regulate maturation of normal megakaryocytes. The
N
-methyl-D-aspartate (NMDA) receptor (NMDAR) provides an additional mechanism for Ca
2+
influx in megakaryocytic cells, but its role remains unclear. We created a model of NMDAR hypofunction in Meg-01 cells using CRISPR-Cas9 mediated knockout of the
GRIN1
gene, which encodes an obligate, GluN1 subunit of the NMDAR. We found that compared with unmodified Meg-01 cells, Meg-01-
GRIN1−/−
cells underwent atypical differentiation biased toward erythropoiesis, associated with increased basal ER stress and cell death. Resting cytoplasmic Ca
2+
levels were higher in Meg-01-
GRIN1−/−
cells, but ER Ca
2+
release and SOCE were lower after activation. Lysosome-related organelles accumulated including immature dense granules that may have contributed an alternative source of intracellular Ca
2+
. Microarray analysis revealed that Meg-01-
GRIN1−/−
cells had deregulated expression of transcripts involved in Ca
2+
metabolism, together with a shift in the pattern of hematopoietic transcription factors toward erythropoiesis. In keeping with the observed pro-cell death phenotype induced by
GRIN1
deletion, memantine (NMDAR inhibitor) increased cytotoxic effects of cytarabine in unmodified Meg-01 cells. In conclusion, NMDARs comprise an integral component of the Ca
2+
regulatory network in Meg-01 cells that help balance ER stress and megakaryocytic-erythroid differentiation. We also provide the first evidence that megakaryocytic NMDARs regulate biogenesis of lysosome-related organelles, including dense granules. Our results argue that intracellular Ca
2+
homeostasis may be more important for normal megakaryocytic and erythroid differentiation than currently recognized; thus, modulation may offer therapeutic opportunities.
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Affiliation(s)
- James I Hearn
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Taryn N Green
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Martin Chopra
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Yohanes N S Nursalim
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Leandro Ladvanszky
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Nicholas Knowlton
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Cherie Blenkiron
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Raewyn C Poulsen
- Department of Medicine, School of Medicine, University of Auckland, Auckland, New Zealand.,Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Dean C Singleton
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - Stefan K Bohlander
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Maggie L Kalev-Zylinska
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand.,LabPlus Haematology, Auckland City Hospital, Auckland, New Zealand
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