Ceramide-1-phosphate blocks apoptosis through inhibition of acid sphingomyelinase in macrophages
Bibliographic record
Abstract
It was reported previously that ceramide-1-phosphate (Cer-1-P) is mitogenic for fibroblasts (Gómez-Muñoz, A., P. A. Duffy, A. Martin, L. O'Brien, H-S. Byun, R. Bittman, and D. N. Brindley. 1995. Mol. Pharmacol. 47: 883-889; Gómez-Muñoz, A., L. M. Frago, L. Alvarez, and I. Varela-Nieto. 1997. Biochem. J. 325: 435-440). We now show that Cer-1-P prevents cell death in bone-marrow-derived macrophages (BMDMs) after withdrawal of macrophage colony-stimulating factor (M-CSF). Removal of M-CSF is known to induce apoptosis in these cells. Cer-1-P blocked activation of the caspase-9/caspase-3 pathway and prevented DNA fragmentation, indicating that the enhancement of cell survival was due to inhibition of apoptosis. M-CSF deprivation resulted in activation of acid sphingomyelinase (A-SMase), increased ceramide levels, and a decrease in intracellular Cer-1-P. Exogenously added Cer-1-P inhibited A-SMase in intact BMDMs at concentrations that also prevented apoptosis. Cer-1-P also inhibited A-SMase in cell homogenates, suggesting a possible direct physical interaction of Cer-1-P with the enzyme. In conclusion, these data demonstrate that Cer-1-P blocks apoptosis in BMDMs through inhibition of A-SMase, thereby reducing ceramide generation. This adds a new dimension to the understanding of the metabolic interrelationship of ceramides and Cer-1-P, and shows how altering the balance of intracellular levels of these mediators can affect cell survival.
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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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".