Abstract 13575: Lack of Both Mitochondrial Proteins Sirt3 and Ucp2 in Mice Recapitulates Many Critical Features of Human Pulmonary Arterial Hypertension (PAH), Including Inflammatory Plexogenic Lesions, Supporting the Metabolic Theory of PAH
Bibliographic record
Abstract
Loss-of function SNPs for Sirt3 (a mitochondrial deacetylase) and Ucp2 (an atypical uncoupling protein enabling mitochondrial calcium entry) have been associated with insulin resistance and obesity in humans; and patients with PAH have insulin resistance without being obese. In a cohort of PAH patients (n=60) we found these SNPs often both in the same patient in a homozygous or heterozygous manner and their presence correlated positively with the degree of PAH upon referral, the presence of type II diabetes and outcomes (death, transplantation). We generated and studied double KO mice for Sirt3 and Ucp2 using closed-chest right heart catheterization and echocardiography and found increasing severity of pulmonary hypertension (PHT) in Sirt3 +/- -Ucp2 +/ - , Sirt3 -/- -Ucp2 +/ - , Sirt3 +/- -Ucp2 -/- and Sirt3 -/- -Ucp2 -/- , associated with decreasing cardiac output and increasing right ventricular hypertrophy, dilatation and dysfunction (TAPSE), compared to wild-type (WT) mice. The LVEDP in all mice was normal. There was increasing severity of vascular remodeling with increasing levels of CD4 + cell infiltration, while Sirt3 -/- -Ucp2 +/- , Sirt3 +/- -Ucp2 -/- and Sirt3 -/- -Ucp2 -/- mice also developed frequent plexogenic lesions. In vivo and in vitro pulmonary artery smooth muscle cells (PASMC) expressed higher levels of Ki67, compared to WT mice. In vitro, the Sirt3 -/- -Ucp2 +/- , Sirt3 +/- -Ucp2 -/- and Sirt3 -/- -Ucp2 -/- PASMC exhibited more apoptosis-resistance, expressed higher nuclear levels of proliferative transcription factors (HIF1, NFATc2), exhibited decreased respiration and higher levels of glycolysis, similarly to previous reports of animal and human PAH PASMC. The Sirt3 -/- -Ucp2 -/- , but not the WT mice, also developed in vivo evidence of insulin resistance. Our work supports the metabolic theory of PAH and shows that these mice exhibit spontaneous severe PHT (without environmental or chemical triggers) in a gene dose-response dependent manner that mimics human PAH. No other mouse model of PHT has shown frequent and predictable plexogenic lesions. Our study is relevant to the PAH patients that carry loss-of-function SNPs of mitochondrial proteins and offers a new mouse model of PAH, with more features of human PAH than previous mice models.
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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 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.011 | 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".