# The Role of the CES1 in the Pathogenesis of Pulmonary Arterial Hypertension

> **NIH NIH R01** · STANFORD UNIVERSITY · 2024 · $539,264

## Abstract

Pulmonary arterial hypertension (PAH) is a life-threatening disease characterized by abnormally elevated
pulmonary pressures and right heart failure resulting in high morbidity and mortality. The pathologic hallmark of
PAH is progressive loss and obstructive remodeling of lung microvessels unresponsive to available therapies.
Studies by our group and others have shown that pulmonary microvascular endothelial cells (PMVECs) derived
from PAH patients are highly susceptible to apoptosis and have a lower capacity to form blood vessels (i.e.,
angiogenesis). Fatty acid oxidation (FAO) is an essential energy source for PMVECs that requires metabolic
coupling of mitochondria and endoplasmic reticulum (ER). Metabolic reprogramming characterized by high
glycolysis, reduced FAO, and mitochondrial/ER dysfunction is a key pathological feature of PAH PMVECs linked
to oxidative stress, endothelial dysfunction, and reduced angiogenesis. Our group has shown that reduced
activity of bone morphogenetic protein receptor 2 (BMPR2), the most common genetic cause of hereditary and
sporadic PAH, promotes metabolic reprogramming but, given the low penetrance of BMPR2 mutations,
alterations in other genes (i.e., “second hit”) are likely necessary for PAH development. In this proposal, we
will show that carboxylesterase 1 (CES1), a lipolytic enzyme responsible for releasing free fatty acids
from the ER to the mitochondria, is required for FAO and metabolic homeostasis in PMVECs. Our
preliminary studies show that CES1 knockdown in healthy PMVECs results in 1) high glycolysis, 2) reduced
FAO, 3) mitochondrial/ER dysfunction, and 4) oxidative stress. Furthermore, loss of CES1 exacerbates
metabolic reprogramming associated with BMPR2 insufficiency, and restoring CES1 expression improves PAH
PMVEC functional status. Based on our preliminary studies, we hypothesize that loss of CES1 in PAH
leads to endothelial dysfunction in PAH through metabolic reprogramming, lipotoxicity, and oxidative
stress. To test this, we propose the following aims: (1): Determine the mechanisms by which loss of CES1
results in metabolic reprogramming and lipotoxicity in PMVECs, (2) Determine whether loss of CES1 promotes
the development and severity of pulmonary hypertension and vasculopathy in mice, and (3) Determine the
contribution of BMPR2 insufficiency and epigenetic repression to reduced CES1 expression in PAH PMVECs.
Using the proposed approach, we will demonstrate that CES1 is essential for properly maintaining and repairing
the pulmonary endothelium and acts as a key modifier of BMPR2 signaling. Given the limited capacity of current
therapies to reverse endothelial dysfunction and prevent small vessel loss, therapeutic interventions that can
restore CES1 expression could serve as a novel treatment approach for PAH.

## Key facts

- **NIH application ID:** 10999076
- **Project number:** 1R01HL172449-01A1
- **Recipient organization:** STANFORD UNIVERSITY
- **Principal Investigator:** VINICIO A DE JESUS PEREZ
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $539,264
- **Award type:** 1
- **Project period:** 2024-08-23 → 2028-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10999076

## Citation

> US National Institutes of Health, RePORTER application 10999076, The Role of the CES1 in the Pathogenesis of Pulmonary Arterial Hypertension (1R01HL172449-01A1). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10999076. Licensed CC0.

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