Histone deacetylase inhibitors synergize with sildenafil to suppress purine metabolism and proliferation in pulmonary hypertension

Authors

Hui Zhang, Cardiovascular Pulmonary Research Laboratories, Department of Pediatrics and Medicine, University of Colorado School of Medicine, Denver, USA.
Angelo D'Alessandro, Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Denver, USA.
Min Li, Cardiovascular Pulmonary Research Laboratories, Department of Pediatrics and Medicine, University of Colorado School of Medicine, Denver, USA.
Julie A. Reisz, Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Denver, USA.
Suzette Riddle, Cardiovascular Pulmonary Research Laboratories, Department of Pediatrics and Medicine, University of Colorado School of Medicine, Denver, USA.
Akshay Muralidhar, Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Denver, USA.
Todd Bull, Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Denver, USA.
Lan Zhao, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.
Evgenia Gerasimovskaya, Cardiovascular Pulmonary Research Laboratories, Department of Pediatrics and Medicine, University of Colorado School of Medicine, Denver, USA.
Kurt R. Stenmark, Cardiovascular Pulmonary Research Laboratories, Department of Pediatrics and Medicine, University of Colorado School of Medicine, Denver, USA. Electronic address: kurt.stenmark@cuanschutz.edu.

Document Type

Article

Abstract

RATIONALE: Sildenafil, a well-known vasodilator known to interfere with purinergic signaling through effects on cGMP, is a mainstay in the treatment of pulmonary hypertension (PH). However, little is known regarding its effects on the metabolic reprogramming of vascular cells, which is a hallmark of PH. Purine metabolism, especially intracellular de novo purine biosynthesis is essential for vascular cell proliferation. Since adventitial fibroblasts are critical contributors to proliferative vascular remodeling in PH, in this study we aimed to investigate if sildenafil, beyond its well-known vasodilator role in smooth muscle cells, impacts intracellular purine metabolism and proliferation of fibroblasts derived from human PH patients. METHODS: Integrated omics approaches (plasma and cell metabolomics) and pharmacological inhibitor approaches were employed in plasma samples and cultured pulmonary artery fibroblasts from PH patients. MEASUREMENTS AND MAIN RESULTS: Plasma metabolome analysis of 27 PH patients before and after treatment with sildenafil, demonstrated a partial, but specific effect of sildenafil on purine metabolites, especially adenosine, adenine, and xanthine. However, circulating markers of cell stress, including lactate, succinate, and hypoxanthine were only decreased in a small subset of sildenafil-treated patients. To better understand potential effects of sildenafil on pathological changes in purine metabolism (especially purine synthesis) in PH, we performed studies on pulmonary fibroblasts from PAH patients (PH-Fibs) and corresponding controls (CO-Fibs), since these cells have previously been shown to demonstrate stable and marked PH associated phenotypic and metabolic changes. We found that PH-Fibs exhibited significantly increased purine synthesis. Treatment of PH-Fibs with sildenafil was insufficient to normalize cellular metabolic phenotype and only modestly attenuated the proliferation. However, we observed that treatments which have been shown to normalize glycolysis and mitochondrial abnormalities including a PKM2 activator (TEPP-46), and the histone deacetylase inhibitors (HDACi), SAHA and Apicidin, had significant inhibitory effects on purine synthesis. Importantly, combined treatment with HDACi and sildenafil exhibited synergistic inhibitory effects on proliferation and metabolic reprogramming in PH-Fibs. CONCLUSIONS: While sildenafil alone partially rescues metabolic alterations associated with PH, treatment with HDACi, in combination with sildenafil, represent a promising and potentially more effective strategy for targeting vasoconstriction, metabolic derangement and pathological vascular remodeling in PH.

Publication Date

2-26-2023

Publication Title

Vascular pharmacology

E-ISSN

1879-3649

Volume

149

First Page

107157

PubMed ID

36849042

Digital Object Identifier (DOI)

10.1016/j.vph.2023.107157

Recommended Citation

Zhang, Hui; D'Alessandro, Angelo; Li, Min; Reisz, Julie A.; Riddle, Suzette; Muralidhar, Akshay; Bull, Todd; Zhao, Lan; Gerasimovskaya, Evgenia; and Stenmark, Kurt R., "Histone deacetylase inhibitors synergize with sildenafil to suppress purine metabolism and proliferation in pulmonary hypertension" (2023). SJHMC Faculty. 19.
https://scholar.barrowneuro.org/sjhmc/19