Misoprostol‐Induced Activation of NF‐kB Functions to Repress the Bnip3 Cell Death Pathway in Neonatal Hypoxia
Bibliographic record
Abstract
Neonatal hypoxia affects more than 50% of preterm infants and is implicated in a number of diseases of prematurity. The exact mechanism for hypoxic injury remains unclear, although it appears that the genetically conserved, pro‐death Bnip3 pathway may play a central role. Previous work has suggested that a transcription factor known as NF‐kB may bind to the Bnip3 promoter region and repress its expression, thereby preventing the induction of cell death. Additionally, our laboratory has shown that misoprostol, a prostaglandin E2 receptor agonist, mitigates the effects of Bnip3 in enterocytes. On this basis, we hypothesize that misoprostol induces the nuclear translocation of NF‐kB through the protein kinase‐A (PKA)/cAMP signaling pathway, resulting in Bnip3 repression and prevention of cell death. To test this, both environmental hypoxia (10% oxygen) and drug treatments were applied to a neonatal rat model to assess the effect of misoprostol and hypoxia on hippocampal, cardiac, and intestinal Bnip3. In the animal study we observed that hypoxia induced a several‐fold increase in Bnip3 protein expression in the intestine, hippocampus and heart. However, when misoprostol was administered to hypoxic rat pups, Bnip3 protein was repressed by more than 87%. In parallel cell culture studies (HCT‐116 cells), expression of Bnip3 increased cell death by 3.8‐fold coupled with a 56.2% decrease in mitochondrial membrane potential compared to empty vector treated cells. Both of these effects were rescued by misoprostol. Additionally, misoprostol induced a 3‐fold increase in intracellular PKA activation, assessed through a fluorescent PKA biosensor, and a nearly 20% increase in nuclear localization of NF‐kB. Further study revealed that expression of wild‐type NF‐kB causes reductions in endogenous Bnip3 protein expression; however, when NF‐kB phosphorylation was inhibited with a neutral alanine mutation (NF‐kB S276A), Bnip3 expression was unchanged. Taken together, both in vivo and in vitro data suggests that misoprostol activates PKA, resulting in nuclear accumulation of NF‐kB which represses Bnip3 protein expression, and ultimately prevents cell death.
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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".