Brain derived neurotrophic factor promotes oocyte maturation through the TrkB-MAPK-PI3K pathway in zebrafish
Bibliographic record
Abstract
Brain-derived neurotrophic factor (BDNF) was previously reported as a positive modulator of zebrafish reproduction, yet the mechanism of action of BDNF that elicits this function is unknown. We hypothesized that the pro-reproductive effects of BDNF in female zebrafish are mediated by TrkB signaling. In zebrafish liver (ZFL) cells, a TrkB antagonist (ANA-12) blocked the stimulatory effect of BDNF on transcript abundance of vitellogenin (vtg1, 2, 4, and 7) and steroidogenic factor 1 (sf-1). No changes were observed in hepatocyte nuclear factor 4 alpha, specificity protein 1, cAMP response element-binding protein 1a, or forkhead box L2. Blocking the mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K), and phospholipase C gamma (PLC-γ) pathways significantly attenuated BDNF-induced upregulation of vtg and sf-1 transcripts. Total vtg protein was increased by BDNF, an effect that was blunted when TrkB, MAPK, PI3K, or PLC-γ were blocked. The estrogen receptor alpha (Esrα) fluorescence immunoreactivity in the ZFL cells treated with BDNF was significantly reduced in the presence of ANA-12. In the zebrafish follicles, BDNF-induced oocyte maturation was attenuated by TrkB, MAPK-, and PI3K inhibitors, but not a PLC-γ blocker. Similarly, the positive effects of BDNF on maturation-related genes 3β-hydroxysteroid dehydrogenase 2 enzyme (3bhsd2), cytochrome P450 family 17, hyaluronan synthase 2, luteinizing hormone receptor, and prostaglandin synthase 2 were significantly attenuated when TrkB, MAPK, or PI3K was blocked. PLC-γ inhibition prevented the BDNF-induced upregulation of 3bhsd1 in the oocytes. This study demonstrates that BDNF promotes vitellogenesis via the TrkB-MAPK/PI3K/PLC-γ signaling pathways. Meanwhile, BNDF enhances oocyte maturation through the TrkB-MAPK/PI3K pathways in zebrafish.
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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) | 0.001 | 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".