Platelet-derived growth factor signaling modulates adult hair follicle dermal stem cell maintenance and self-renewal
Bibliographic record
Abstract
Abstract Hair follicle regeneration is dependent on reciprocal signaling between epithelial cells and underlying mesenchymal cells within the dermal papilla. Hair follicle dermal stem cells reside within the hair follicle mesenchyme, self-renew in vivo, and function to repopulate the dermal papilla and regenerate the connective tissue sheath with each hair cycle. The identity and temporal pattern of signals that regulate hair follicle dermal stem cell function are not known. Here, we show that platelet-derived growth factor signaling is crucial for hair follicle dermal stem cell function and platelet-derived growth factor deficiency results in a progressive depletion of the hair follicle dermal stem cell pool and their progeny. Using αSMACreER T2 :Rosa YFP :Pdgfrα flox mice, we ablated Pdgfrα specifically within the adult hair follicle dermal stem cell lineage. This led to significant loss of hair follicle dermal stem cell progeny in connective tissue sheath and dermal papilla of individual follicles, and a progressive reduction in total number of anagen hair follicles containing YFP +ve cells. As well, over successive hair cycles, fewer hair follicle dermal stem cells were retained within each telogen hair follicle suggesting an impact on hair follicle dermal stem cell self-renewal. To further assess this, we grew prospectively isolated hair follicle dermal stem cells (Sox2GFP +ve αSMAdsRed +ve ) in the presence or absence of platelet-derived growth factor ligands. Platelet-derived growth factor-BB enhanced proliferation, increased the frequency of Sox2 +ve hair follicle dermal stem cell progeny and improved inductive capacity of hair follicle dermal stem cells in an ex vivo hair follicle formation assay. Similar effects on proliferation were observed in adult human SKPs. Our findings impart novel insights into the signals that comprise the adult hair follicle dermal stem cell niche and suggest that platelet-derived growth factor signaling promotes self renewal, is essential to maintain the hair follicle dermal stem cell pool and ultimately their regenerative capacity within the hair follicle.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.000 | 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 teacher head, 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".