Human Chorionic Gonadotropin-Dependent Up-Regulation of Chemokine CXC Motif Receptor 4 (CXCR4) and Its Ligand Stromal Cell-Derived Factor-1 (SDF1) in Equine Preovulatory Follicles.
Bibliographic record
Abstract
Ovulation shares numerous features of a classic inflammatory reaction. Stromal cell-derived factor-1 (SDF1), a chemokine of the CXC subfamily, is constitutively expressed in a wide variety of tissues and its interaction with chemokine CXC motif receptor 4 (CXCR4) is involved in leukocyte attraction, tissue remodelling and angiogenesis. The objective of the study was to characterize the expression and regulation of CXCR4 and its ligand SDF-1 in equine follicles during the ovulatory process. Preovulatory follicles (POF) were isolated during estrus 0, 12, 24, 30, 33, 36 and 39 h after an ovulatory dose of hCG (ovulation occurred 39-42 h post-hCG), and corpora lutea (CL) were obtained on day 8 of the estrous cycle. Follicle walls (theca interna [TI] with attached granulosa cells [GC]) and isolated preparations of GC and TI were obtained, and total RNA extracts were prepared and analyzed by semi-quantitative RT-PCR/Southern blot analyses. Results showed an increase expression of CXCR4 in equine POF prior to ovulation. Levels of CXCR4 transcripts were low 0-24 h post-hCG, increased markedly 33-39 h post-hCG in both GC and TI (P < 0.05), and decreased to moderate levels in day-8 CL. Western blotting and immunohistochemical analyses confirmed high levels of CXCR4 protein in both follicular cell types after hCG. A tissue blot analysis revealed that levels of CXCR4 mRNA were high in thymus, moderate in lung and spleen, and low in other equine tissues tested. The regulation of SDF1 mRNA in equine follicles followed a different pattern. Levels of SDF1 transcripts remained very low or undetectable in GC at all time points (0-39 h). In contrast, SDF1 transcripts in TI were high 0-36 h and decreased 39 h post-hCG (P < 0.05). The tissue blot analysis revealed elevated expression of SDF1 mRNA in most tissues tested. Thus, this study characterizes for the first time the gonadotropin-dependent regulation and cellular localization of CXCR4 and SDF1 in preovulatory follicles of a monoovulatory species. The selective expression of SDF1 mRNA in TI, and the combined expression and up-regulation of CXCR4 in GC and TI, suggests that thecal SDF1 acts as an autocrine (on TI) and a paracrine (on GC) factor to regulate follicular rupture. Further investigations will be needed to identify events downstream of SDF1-CXR4 activation. This study was supported by NSERC of Canada.
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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) | 0.000 | 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) | 0.000 | 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".