Abstract P241: Calpain-1 Is Increased in Mitochondria and Contributes to Mitochondrial ROS Generation in High Glucose--Stimulated Endothelial Cells and Endothelial Dysfunction in Mouse Models of Diabetes
Bibliographic record
Abstract
Objectives: Elevated levels of reactive oxygen species (ROS) are the initial source of endothelial dysfunction in diabetes. Calpain has been implicated in diabetic vascular complications. The present study was to investigate the role of calpain in mitochondrial ROS generation in endothelial cells and vascular dysfunction in diabetic mice. Methods: Endothelial cells cultured from human umbilical vein (HUVEC) were stimulated with high glucose. Calpain activity and protein were determined in mitochondria of HUVEC. Intracellular and mitochondrial ROS generation as well as apoptosis were measured. Type I diabetic OVE 26 mice and type II diabetic db/db mice with calpastatin over-expression (OVE26/CAST and db/db-CAST) were generated, respectively. Type I diabetes was also induced in both wild-type and Tg-CAST mice by injection of streptozocin (STZ). The endothelium-dependent relaxation of aortic ring was measured. Results: High glucose significantly increased calpain-1 protein, calpain activity and ROS generation in mitochondria of HUVEC. Pharmacological inhibition of calpain or over-expression of calpastatin abrogated high glucose-induced intracellular ROS production, mitochondrial ROS generation and apoptosis in HUVEC. Incubation of isolated mitochondria with calpain-1 protein significantly induced its ROS generation and the membrane potential. In diabetic mice, calpain activity was induced in aortic vessels, which correlated with an increase in ROS production and protein tyrosine nitration. Over-expression of calpastatin prevented calpain activity, reduced ROS production and inhibited protein tyrosine nitration in diabetic mice. Aortic ring segments from diabetic mice exhibited a significant reduction in vascular relaxation to acetylcholine, which was reversed by over-expression of calpastatin in Tg-CAST, OVE26/CAST and db/db-CAST mice. Conclusions: This study has demonstrated a novel role of calpain in mitochondrial ROS generation, which contributes to apoptosis in endothelial cells during hyperglycemia. Thus, over-expression of calpastatin inhibits reduces ROS production and ameliorates endothelium-dependent vascular dysfunction in mouse models of diabetes.
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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) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 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".