The Involvement of Reactive Oxygen Species in Polyploidization of the M-07e Human Megakaryocytic Cell Line.
Bibliographic record
Abstract
Abstract Hematopoietic cells mature in the bone marrow under the control of a diversity of growth factors and the influence of various cell types producing superoxide and other reactive oxygen species (ROS). As ROS may regulate activities of redox-sensitive enzymes implicated in a wide range of cellular processes, we have exposed the human megakaryocytic cell line M-07e to hydrogen peroxide (H2O2) at concentrations that increased intracellular ROS and examined whether expression of the megakaryocytic programme could be enhanced. The growth-factor dependent M-07e cells display surface markers characteristic of both early myeloid progenitors and more committed members of the magakaryocyte (Mk) lineage, such as glycoproteins GPIIb-IIIa (CD41) and GPIb (CD42). H2O2 significantly reduced cell proliferation without affecting viability. After 4 days of exposure to this reagent, expression of the early Mk marker CD41 was 1.2 times higher than that of control cells. Although no change in the expression of the late Mk marker CD42 was detected, exposure to H2O2 was found to increase the incidence of multinucleate cells, polyploidy and abnormal microtubule organising centre numbers. Investigation of this phenomenon on synchronized M-07e cells revealed that H2O2 arrested cytokinesis at a late stage and that some nuclei were still able to incorporate bromodeoxyuridine (BrdU). Cell division was similarly impaired when M-07e cells were either exposed to botulin toxin C3 transferase or Y-27362 inhibitor, suggesting that H2O2 treatments affected members of the Rho family of small GTP-binding proteins and/or their effectors. Together, these findings indicate that endoreplication in Mk may be linked to changes in the cellular redox state of these cells and support the concept that differentiation and polyploidization are independently regulated events.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".