The Role of Oxygen Tension and Insulin-Like Growth Factor Signaling in the Placental Mesenchymal Stem Cell Fate
Bibliographic record
Abstract
The human placenta of different gestational ages is a readily available source for isolation of adult mesenchymal stem cell (MSC) for potential use in regenerative therapies. The chorionic villous region, the largest component of a placenta that interfaces with the maternal circulation, is a rich source of placental MSCs (PMSCs). To remain multipotent, PMSCs are best maintained in culture conditions that mimic the in vivo microenvironment. Insulin like growth factors (IGFs, IGF-I and -II) and oxygen tension are two of the most important microenvironmental factors in the placenta. They are of low concentration or tension respectively, at early gestation, and increase as pregnancy progresses. In this thesis, we investigated the role and cellular mechanisms by which IGFs and low oxygen tension determine PMSC fate. The main hypothesis is that the interaction between IGFs and oxygen tension determines PMSC fate towards self-renewal or differentiation. We used cell proliferation assay, immunoblotting, real-time PCR, and cell monolayer staining to evaluate the role of IGF and oxygen tension on PMSC multipotency and differentiation. We found that low oxygen tension was a major determinant of PMSCs proliferation and multipotency, and to delay differentiation. Also, PMSC response to IGF stimulation and low oxygen tension was gestational age dependent — preterm PMSCs being more multipotent and proliferative than term PMSCs. IGF-I and IGF-II promoted PMSC proliferation and multipotency via IGF-IR or IR, depending on oxygen tension. IGFs enhanced PMSC differentiation towards the osteogenic lineage which was transduced by ERK1/2 and AKT signaling cascades. We conclude that IGFs and oxygen tension act synergistically or antagonistically, mimicking in vivo microenvironmental conditions, to determine PMSC fate towards multipotency or differentiation. The appropriate combination of IGFs and oxygen tension can be used to maintain stem cells in multipotency, or to be induced towards a specific progenitor cell lineage for successful use in tissue regeneration therapies.
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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) | 0.001 | 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".