Diabetic Vascular Calcification Mediated by the Collagen Receptor Discoidin Domain Receptor 1 via the Phosphoinositide 3-Kinase/Akt/Runt-Related Transcription Factor 2 Signaling Axis
Bibliographic record
Abstract
Objective— Vascular calcification is a common and severe complication in patients with atherosclerosis which is exacerbated by type 2 diabetes mellitus. Our laboratory recently reported that the collagen receptor discoidin domain receptor 1 (DDR1) mediates vascular calcification in atherosclerosis; however, the underlying mechanisms are unknown. During calcification, vascular smooth muscle cells transdifferentiate into osteoblast-like cells, in a process driven by the transcription factor RUNX2 (runt-related transcription factor 2). DDR1 signals via the phosphoinositide 3-kinase/Akt pathway, which is also central to insulin signaling, and upstream of RUNX2, and this led us to investigate whether DDR1 promotes vascular calcification in diabetes mellitus via this pathway. Approach and Results— Ddr1 +/+ ; Ldlr −/− (single knock-out) and Ddr1 −/− ; Ldlr −/− (double knock-out) mice were placed on high-fat diet for 12 weeks to induce atherosclerosis and type 2 diabetes mellitus. Von Kossa staining revealed reduced vascular calcification in the aortic arch of double knock-out compared with single knock-out mice. Immunofluorescent staining for RUNX2 was present in calcified plaques of single knock-out but not double knock-out mice. Primary vascular smooth muscle cells obtained from Ddr1 +/+ and Ddr1 −/− mice were cultured in calcifying media. DDR1 deletion resulted in reduced calcification, a 74% reduction in p-Akt levels, and an 88% reduction in RUNX2 activity. Subcellular fractionation revealed a 77% reduction in nuclear RUNX2 levels in Ddr1 −/− vascular smooth muscle cells. DDR1 associated with phosphoinositide 3-kinase, and treatment with the inhibitor wortmannin attenuated calcification. Finally, we show that DDR1 is important to maintain the microtubule cytoskeleton which is required for the nuclear localization of RUNX2. Conclusions— These novel findings demonstrate that DDR1 promotes RUNX2 activity and atherosclerotic vascular calcification in diabetes mellitus via phosphoinositide 3-kinase/Akt signaling.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 teacher head, 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".