Effect of lysophospholipids on signaling in the Human jurkat T Cell Line
Bibliographic record
Abstract
Abstract Lysophospholipids have recently been demonstrated to induce activation and proliferation of fibroblasts and other cell lineages by interacting with high affinity cell surface receptors leading to specific intracellular signaling events. Platelet activation, likely at the site of injury or inflammation, results in increased production of lysophospholipids suggesting a possible source of lysophospholipids. We have recently demonstrated that high concentrations of lysophospholipids are present in ascites and plasma from ovarian cancer patients, suggesting that physiologically produced lysophospholipids could interact with cells present in these fluids, including lymphocytes, and alter their function. We demonstrate herein that lysophosphatidic acid (LPA), lysophosphatidylserine (LPS), and sphingosylphosphorylcholine (SPC) activate the Jurkat T cell line. Each of the lysophospholipids induced a transient increase in cytosolic free calcium ([Ca2+]i) in Jurkat cells. Increases in [Ca2+]i were cross‐desensitized by LPA, LPS and SPC, suggesting that the lysophospholipids share the same receptor(s) or that their downstream signaling pathways converge or interact. Lysophosphatidylgycerol (LPG), a competitive inhibitor of the putative LPA receptor, inhibited the calcium releasing activity of LPA, but not that of LPS and SPC, suggesting that these lysophospholipids interact with different receptors and that desensitization is due to interactions in downstream signaling pathways. The ability of the lysophospholipids to induce increases in [Ca2+]i was attenuated, but not completely blocked, by increases in [Ca2+]i induced by activation of the thrombin receptor. In contrast, increases in [Ca2+]i induced by the lysophospholipids and cross‐linking the CD3 component of the T cell receptor complex with the UCHT1 antibody did not undergo heterologous desensitization. Strikingly, LPA is sufficient to stimulate proliferation of Jurkat cells in serum‐free medium or in synergy with low concentrations of fetal bovine serum. In addition, LPA also increased the production of the T cell growth factor, interleukin 2 (IL‐2), by Jurkat cells treated with phorbol esters. LPS, in contrast, inhibited Jurkat proliferation while increasing IL‐2 production and SPC inhibited both processes. Thus, although all three lysophospholipids were sufficient to induce a transient increase in [Ca2+]i in Jurkat cells, they induced markedly different physiological consequences. © 2005 Wiley‐Liss, Inc.
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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 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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".