Dexamethasone enhances erythropoietic differentiation of embryonic stem cells
Bibliographic record
Abstract
We have studied the in vitro differentiation of murine embryonic stem cells (ES) towards erythropoiesis and expression of genes during this process. It has been reported that dexamethasone directs ES cells towards erythrocytic differentiation but the mechanism of gene regulation induced by dexamethasone is not well understood. We hypothesized that dexamethasone induces upregulation of erythropoietic genes such as GATA-1, FLK-1, EPO-R, and directs ES cells towards erythropoietic differentiation. Murine ES cells (129 CCE) obtained from Dr. Nagy laboratory, Canada, were subjected to the in vitro primary hematopoietic differentiation media containing methylcellulose, IMDM, IL -3, IL-6, and SCF (stem cell factor) without LIF (leukemia inhibitory factor) to promote embryoid body (EB) formation. Total RNA was collected on day 3, 5, and 9 EBs for gene expression studies using RT-PCR. On day 9, EBs were subjected to secondary differentiation using three different cytokines and growth factors combination, (1) SCF, EPO, dexamethasone, IGF, (2) SCF, IL-3, IL-6, TPO, (3) SCF IL-3, IL-6, TPO, EPO. Total RNA from day12 of secondary differentiated ES cells was collected to study cytokines and growth factors dependent erythrocytic differentiation and gene regulation, using RT-PCR. Our results demonstrate upregulation of Gata-1, Flk-1, HoxB-4, Epo-R, and globin genes (α-globin, BH-1 globin, b-major globin, e-globin, and z-globin) in the 9 days old EBs, whereas RNA collected from 5 days old EBs showed expression of HoxB-4, e-globin, γ-globin, BH1-globin, and FLK-1. Three days old EBs showed only HoxB-4 and FLK-1 gene expression and lack of expression of globin genes, indicating that erythropoiesis-specific genes and hemoglobin switch activate later. Gene expression studies of RNA collected from secondary differentiated ES cells and media containing dexamethasone showed downregulation of GATA-3 and upregulation of GATA-1, Flk-1, and Epo-R in comparison to the two other cytokines and growth factors media combination. These results confirm our hypothesis that dexamethasome induces erythropoiesis by downregulating GATA −3 and upregulating erythropoietic genes such as GATA-1, Flk-1, and Epo-R. The morphological characteristics of cells after secondary differentiation showed enhanced production of erythrocytic precursors in dexamethasone containing media, which corresponded with molecular studies.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".