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Platelet-like particle formation in the human megakaryoblastic leukaemia cell lines, MEG-01 and MEG-01s
1Osaka Prefectural College of Health Science, Habikino, Japan.
Abstract:
The platelet-sized particle formation in the human megakaryoblastic leukaemia cell line MEG-01 and its subline MEG-01s was examined. MEG-01 and MEG-01s cells spontaneously released platelet-sized particles into the culture medium, in which the cells occasionally extended cytoplasmic processes similar to those of megakaryocyte proplatelets. Scanning electron microscopic images showed cytoplasmic processes elongated from blebs on the MEG-01 and MEG-01s cell surface and were constricted between segments of platelet size. Immunofluorescence staining with anti-tubulin antibody showed that the cytoplasmic processes contained microtubules that were organized into a ring, which is a characteristic of circulating platelets. Some platelet-sized particles, probably released by ruptures at the sites of the process constriction, were metabolically active in an MTT assay (about 50%). Some particles also expressed the platelet-specific glycoproteins GPIIb, IIIa and GMP-140. Rarely, in response to thrombin, particles underwent a shape change from spherical to a shape with irregular membrane protrusions and fine filopodia, and aggregating with one another. The particles also had increased GMP-140 (P-selectin) expression with the addition of thrombin. These results show the usefulness of the MEG-01 and MEG-01s cell lines for the study of thrombopoiesis.
Insights
Human megakaryoblastic leukemia cell lines MEG-01 and MEG-01s spontaneously form platelet-sized particles. These particles exhibit platelet characteristics and function, making the cell lines useful for studying thrombopoiesis.
Area of Science:
- Hematology
- Cell Biology
- Leukemia Research
Background:
- Megakaryocytes are the source of platelets in the blood.
- Understanding megakaryocyte differentiation and proplatelet formation is crucial for hematological research.
- Leukemia cell lines offer valuable models for studying normal cellular processes.
Purpose of the Study:
- To investigate platelet-sized particle formation in MEG-01 and MEG-01s cell lines.
- To characterize the properties and functions of these cell-derived particles.
- To assess the utility of these cell lines as a model for thrombopoiesis research.
Main Methods:
- Culturing human megakaryoblastic leukemia cell lines (MEG-01 and MEG-01s).
- Scanning electron microscopy to visualize particle formation.
- Immunofluorescence staining for tubulin and platelet glycoproteins (GPIIb, IIIa, GMP-140).
- MTT assay for metabolic activity and thrombin stimulation for functional assays.
Main Results:
- MEG-01 and MEG-01s cells spontaneously released platelet-sized particles with cytoplasmic processes containing microtubules.
- Approximately 50% of the particles were metabolically active and expressed platelet-specific glycoproteins.
- Particles showed thrombin-induced shape change, aggregation, and increased GMP-140 expression.
Conclusions:
- The MEG-01 and MEG-01s cell lines are capable of forming platelet-sized particles resembling those produced during thrombopoiesis.
- These particles possess key functional and molecular characteristics of mature platelets.
- These cell lines serve as a valuable in vitro model for studying thrombopoiesis and platelet biology.