Oct4 Expression and Mesenchymal Stromal Cell Plasticity
Bibliographic record
Abstract
Abstract Mesenchymal stromal cells (MSCs) have the capacity to differentiate along multiple lineages and are now in cell therapy clinical trials, especially for injured myocardium. Mechanisms mediating tissue regeneration remain unclear and are likely multifactorial. We recently showed that bone marrow-derived murine MSCs can acquire cardiac markers but retain MSCs properties when co-cultured with rat embryonic cardiomyocytes (RECs) (Rose et. al., Stem Cells. Aug7, 2008). The aim of our study was to determine whether expression of the embryonic transcription factor, Oct4 was modulated in this model of MSC plasticity. Wild-type Fvb mouse MSCs (passage 4) were co-cultured with RECs for 5 days and expression of Oct4, Nanog and Sox2, was analyzed by qRT-PCR with mouse-specific primers. Oct4 protein was assessed by immunocytochemistry (ICC) and flow cytometry (FC). The MSCs expressed Oct4, Nanog, and Sox2 transcripts. After co-culture, mRNA levels for Oct4 and Sox2 were upregulated 2.6±1.2-fold (p<0.05) and 2.4±0.4-fold (p<0.05), respectively, compared with MSCs controls, in contrast to Nanog gene expression which remained unchanged (1.2±0.3-fold; p=ns). 83±9% of MSCs nuclei were positive for Oct4 by ICC. To distinguish mouse from rat cells in co-culture, cells were stained with an anti-mouse CD44 antibody which does not cross react with rat CD44. CD44 is expressed on all MSCs and absent on RECs. Flow cytometry showed that Oct4 was over-expressed in CD44+ cells after co-culture. Our data demonstrate that these embryonic transcription factors are constitutively expressed in murine MSCs and that Oct4 and Sox2 transcript levels are increased after co-culture with RECs. Oct4, Nanog and Sox2 are known to maintain pluripotency of embryonic stem cells. Moreover, induced pluripotent stem cells can be generated from mouse fibroblasts by the introduction of Oct4 and Sox2 without the need for Nanog (Cell126:663,2006). Our data infer that embryonic transcription factors are involved in MSCs progression to different cell lineages. Our findings suggest new mechanisms that may mediate MSC plasticity.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".