Abstract 19343: Chemical Chaperone Mediated Inhibition of Activating Transcription Factor 6 (ATF6) is a Novel Therapy in Pulmonary Arterial Hypertension (PAH)
Bibliographic record
Abstract
The high mortality associated with PAH is in part, due to the poorly understood pathogenesis. Endoplasmic reticulum (ER)-stress is a potential commonality among many molecular triggers of PAH, including mutations, viruses, inflammation and hypoxia. The ER forms a functional unit with the mitochondria (the ER-mito unit), allowing for exchange of Ca2+. Recently, we showed that ER-mito unit disruption was critical in PAH pathogenesis. In pulmonary artery smooth muscle cells (PASMCs), ER-stress activated the transcription factor ATF6, increased levels of the ER protein Nogo, disrupted the ER-mito unit, and resulted in the apoptosis-resistance that is central to pulmonary vascular remodeling in PAH. Chemical chaperones including the FDA-approved 4-phenylbutyrate (PBA) attenuate ER-stress and have been studied in metabolic diseases and cancer. We hypothesized that attenuation of ER stress-induced ATF6 activation with PBA will prevent the disruption of the ER-mito unit and prevent/reverse PAH. Hypoxic mice or monocrotaline-injected rats were treated with PBA in their drinking water (~500mg/kg/day) in prevention (days 0-28) and reversal (days 14-28) protocols. Mechanistic studies were performed in lungs and PASMCs exposed to hypoxia. PBA decreases ATF6 activation (nuclear localization, luciferase, target gene (Nogo/GRP78) expression) and normalizes mitochondrial function (mitochondrial-Ca2+, membrane potential, reactive oxygen species). Both in vivo and in vitro, PBA suppresses proliferation (Ki67) and induces apoptosis (TUNEL). Treated mice had less pulmonary artery remodeling, improved hemodynamics, decreased right ventricular hypertrophy and better functional capacity compared to vehicle-treated controls (see table; data presented as mean±SEM). Treated rats responded similarly. Chemical chaperones improve PAH by inhibiting ATF6 activation, a pathway compatible with several PAH-triggers that induce ER-stress.
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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 | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 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".