Abstract 110: The Role Of Sphingosine-1-Phosphate In The Reverse Transendothelial Migration Of Aortic Intimal Myeloid Cells
Bibliographic record
Abstract
CD11c + myeloid cells (MCs) reside in the normal aortic arch intima at regions predisposed to atherosclerosis. We showed that reverse transendothelial migration (RTM) of these intimal MCs into the arterial circulation is a protective immune response. RTM is triggered by systemic stimulation of cytokine and toll-like receptors (TLRs), e.g., TLR4 by lipopolysaccharide (LPS), and is inhibited by hypercholesterolemia and associated intimal MC lipid accumulation. We hypothesize that signaling by sphingosine-1-phosphate (S1P) and its receptors (S1PRs) is required for RTM of intimal MCs following systemic stimulation of TLRs, analogous to its role in immune cell trafficking in lymphoid tissues. In the lesser curvature of the aortic arch of wild type C57BL/6 mice, LPS induced the expression of S1P receptors 1 & 3, and sphingosine kinase 1 (SphK1). FTY720, a broad-spectrum S1P receptor modulator, blocked LPS-induced RTM, as determined by the enumeration of CD11c+ MCs by en face immunoconfocal microscopy. S1PR1 or S1PR3 inhibitors blocked RTM in a partial and additive manner, suggesting a role for both S1P receptors in intimal MC migration. Initial experiments show that Cre-mediated deletion of S1PR1 in myeloid cells partially blocks LPS-induced RTM, suggesting that myeloid-specific S1PR1 signaling is implicated in the migratory process. Furthermore, global loss or hematopoietic deficiency of SPHK1 reduced the abundance of CD11c+ MCs in the aortic intima, suggesting an additional role for myeloid S1P production in the homeostatic maintenance of resident aortic immune cells. Cre-mediated deletion of S1PR1 in endothelial cells also reduced the abundance of intimal MCs, providing further evidence that S1P signaling in the intima is important in maintaining the intimal MC population. Thus, functional and expression studies suggest that S1P signaling plays a role in both the maintenance of resident intimal MCs and LPS-induced RTM.
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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) | 0.005 | 0.002 |
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".