Identification and immune regulation of 25-hydroxyvitamin D-1-<i>α</i>-hydroxylase in murine macrophages
Bibliographic record
Abstract
Receptors for 1,25(OH)2vitaminD3 are found in most immune cells and important immunological effects have been described in vitro, reflected by its capacity to prevent autoimmunity and to prolong graft survival. The aim of this study was to examine the presence and nature of the enzyme responsible for final activation of the molecule, 1-alpha-hydroxylase, in murine macrophages and to analyse its regulation and possible role in the immune system. Peritoneal macrophages from C57Bl/6 mice were incubated with lipopolysaccharide (LPS; 100 microg/ml), interferon-gamma (IFN-gamma; 500 U/ml) or a combination of both. By quantitative reverse transcriptase-polymerase chain reaction, using primers based on the murine renal cDNA sequence, low levels of 1-alpha-hydroxylase mRNA were detected in freshly isolated cells (18 +/- 7 x 10-6 copies/beta-actin copies). Analysis of the cDNA sequence of the gene revealed identical coding sequences for the macrophage and renal enzymes. mRNA levels rose three-fold with LPS (NS), but a six-fold increase was seen after IFN-gamma stimulation (P < 0.05). Combining LPS and IFN-gamma did not result in a major additional increase, but addition of cyclosporin A further increased levels 2.5-fold both in IFN-gamma- and combination-stimulated cells (P < 0.05). Time course analysis revealed that up-regulation of 1-alpha-hydroxylase was a late phenomenon, preceded by the up-regulation of activating macrophage products such as IL-1 and tumour necrosis factor-alpha. Finally, a defect in 1-alpha-hydroxylase up-regulation by immune stimuli was found in autoimmune non-obese diabetic mice. In conclusion, we propose that the up-regulation of 1-alpha-hydroxylase in activated macrophages, resulting in the synthesis of 1,25(OH)2D3, might be a negative feedback loop in inflammation. A defect in this system might be an additional element in tipping the balance towards autoimmunity.
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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 | 0.000 |
| 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".