Agonist Activation of F-Actin-Mediated Eosinophil Shape Change and Mediator Release Is Dependent on Rac2
Bibliographic record
Abstract
BACKGROUND: Tissue recruitment and activation of eosinophils contribute to allergic symptoms by causing airway hyperresponsiveness and inflammation. Shape changes and mediator release in eosinophils may be regulated by mammalian Rho-related guanosine triphosphatases. Of these, Rac2 is essential for F-actin formation as a central process underlying cell motility, exocytosis, and respiratory burst in neutrophils, while the role of Rac2 in eosinophils is unknown.We set out to determine the role of Rac2 in eosinophil mediator release and F-actin-dependent shape change in response to chemotactic stimuli. METHODS: Rac2-deficient eosinophils from CD2-IL-5 transgenic mice crossed with rac2 gene knockout animals were examined for their ability to release superoxide through respiratory burst or eosinophil peroxidase by degranulation. Eosinophil shape change and actin polymerization were also assessed by flow cytometry and confocal microscopy following stimulation with eotaxin-2 or platelet-activating factor. RESULTS: Eosinophils from wild-type mice displayed inducible superoxide release, but at a small fraction (4-5%) of human eosinophils. Rac2-deficient eosinophils showed significantly less superoxide release (p < 0.05, 26% less than wild type). Eosinophils lacking Rac2 had diminished degranulation (p < 0.05, 62% less eosinophil peroxidase) and shape changes in response to eotaxin-2 or platelet-activating factor (with 68 and 49% less F-actin formation, respectively; p < 0.02) compared with wild-type cells. CONCLUSION: These results demonstrate that Rac2 is an important regulator of eosinophil function by contributing to superoxide production, granule protein release, and eosinophil shape change. Our findings suggest that Rho guanosine triphosphatases are key regulators of cellular inflammation in allergy and asthma.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.003 | 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".