CTRP7 as a Molecular Biomarker for Predicting Responsiveness to Pulmonary Vasodilators: Insights from Human and Animal Studies in Pulmonary Arterial Hypertension
Bibliographic record
Abstract
Abstract Background Pulmonary arterial hypertension (PAH) is a life-threatening condition. Although pulmonary vasodilators have shown promise in managing PAH, the overall prognosis improvement is modest, partly because of the absence of a biomarker for guiding their selection. This study aimed to identify the molecular-based predictors of responsiveness to pulmonary vasodilators by combining human and basic studies. Methods and Results RNA sequencing was conducted on cultured pulmonary artery smooth muscle cells (PASMCs) from patients with and without PAH, identifying variations in 2,076 genes. The candidates were narrowed down to established clinical biomarkers, and their plasma levels were assessed in PAH (n = 123) and non-PAH patients (n = 25). C1q/TNF-related protein 7 (CTRP7) exhibited elevated expression in PASMCs (5.37 Log2 fold change, p < 0.01), and the plasma of patients with PAH compared to non-PAH (28.2 (9.3– 101.2) vs. 9.32 (4.6–18.6) ng/ml, p < 0.01). A plasma assessment revealed a significant correlation between CTRP7 and interleukin 6 (IL-6) levels (r = 0.544, p < 0.001). Chromatin immunoprecipitation demonstrated that IL-6 upregulated CTRP7 expression in PASMCs. Among pivotal factors, CTRP7 reduced prostacyclin analog receptor (PTGIR) expression through Rab5a-mediated internalization, resulting in diminished responsiveness to selexipag (a prostacyclin analog). Incorporating the human study, hypoxic PH mice demonstrated reduced PTGIR expression in the pulmonary arteries, which correlated with limited responses to selexipag treatment (low cardiac output and persistent pulmonary artery resistance), which was mitigated by silencing CTRP7 expression in the pulmonary arteries using adeno-associated virus 6. Conclusions Among the candidates with increased expression in patients with PAH based on RNA sequencing of PASMCs, CTRP7 demonstrated elevated plasma levels compared to non-PAH. CTRP7 regulated PTGIR internalization via inflammation and Rab5a, influencing responsiveness to selexipag. CTRP7 emerged as a compelling biomarker for predicting responsiveness to prostacyclin analogs, potentially advancing the development of innovative PAH treatment strategies. Novel and Significance What Is Known? Pulmonary arterial hypertension (PAH) is a life-threatening vascular disease with limited treatment options. Although pulmonary vasodilators have shown promise in managing PAH, the overall improvement in prognosis is modest. Further research is needed to understand the molecular features of pulmonary vasodilators and identify biomarkers for appropriate selection. What New Information Does This Article Contribute? C1q/TNF-related protein 7 (CTRP7) was found to be elevated in the pulmonary artery smooth muscle cells (PASMCs) and plasma of patients with pulmonary arterial hypertension (PAH). This study established a connection between inflammation and pulmonary vascular responsiveness via CTRP7-mediated internalization and degradation of the prostacyclin analog receptor. This study indicated the possibility of using plasma CTRP levels as a clinical biomarker to monitor pulmonary responsiveness, which can contribute to the development of novel treatment strategies for patients with PAH. Pulmonary arterial hypertension (PAH) is a life-threatening and enigmatic lung vascular disorder characterized by progressive pulmonary vascular remodeling and vasoconstriction. Despite significant advancements in the treatment of PAH using pulmonary vasodilators, some individuals display limited responses, primarily due to a lack of understanding of the molecular features of each pulmonary vasodilator and the absence of a biomarker for appropriate selection. The present study aimed to identify promising biomarkers for predicting a patient’s responsiveness to pulmonary vasodilators through a two-step approach, involving RNA sequencing of PASMCs and the measurement of plasma levels. CTRP7 emerged as a prominent biomarker, displaying increased expression in both PASMCs and plasma obtained from patients with PAH. Mechanistically, IL-6 transcriptionally modulated CTPR7, leading to the internalization and degradation of PTGIR, resulting in a reduced response to selexipag (prostacyclin analog) in PASMCs. Integrating the human studies, a hypoxic mouse model exhibited lower PTGIR expression in pulmonary arteries, correlating with limited responses to selexipag treatment, which were ameliorated by silencing CTRP7 expression in pulmonary arteries using adeno-associated virus 6 transduction. This study collectively demonstrates that CTRP7 emerges as a compelling biomarker for predicting responsiveness to prostacyclin analogs, with the potential to advance the development of innovative PAH treatment strategies.
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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 | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".