Fetal, but Not Postnatal, Deletion of Semaphorin-Neuropilin-1 Signaling Affects Murine Alveolar Development
Bibliographic record
Abstract
The disruption of angiogenic pathways, whether through genetic predisposition or as a consequence of life-saving interventions, may underlie many pulmonary diseases of infancy, including bronchopulmonary dysplasia. Neuropilin-1 (Nrp1) is a transmembrane receptor that plays essential roles in normal and pathological vascular development and binds two distinct ligand families: vascular endothelial growth factor (Vegf) and class 3 semaphorins (Sema3). Although Nrp1 is critical for systemic vascular development, the importance of Nrp1 in pulmonary vascular morphogenesis is uncertain. We hypothesized that Sema3-Nrp1 and Vegf-Nrp1 interactions are important pathways in the orchestration of pulmonary vascular development during alveolarization. Complete ablation of Nrp1 signaling would therefore lead to interruption of normal angiogenic and vascular maturation processes that are relevant to the pathogenesis of bronchopulmonary dysplasia. We have previously shown that congenital loss of Sema3-Nrp1 signaling in transgenic Nrp1(Sema-) mice resulted in disrupted alveolar-capillary interface formation and high neonatal mortality. Here, pathohistological examination of Nrp1(Sema-) survivors in the alveolar period revealed moderate to severe respiratory distress, alveolar hemorrhaging, abnormally dilated capillaries, and disintegrating alveolar septa, demonstrating continued instability of the alveolar-capillary interface. Moreover, consistent with a reduced capillary density and consequent increases in vascular resistance, hypertensive remodeling was observed. In contrast, conditional Nrp1 deletion beginning at postnatal day 5 had only a transient effect upon alveolar and vascular development or pneumocyte differentiation despite an increase in mortality. Our results demonstrate that although Sema3-Nrp1 signaling is critical during fetal pulmonary development, Nrp1 signaling does not appear to be essential for alveolar development or vascular function in the postnatal period.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".