Investigating DNA Methyltransferase 3A (DNMT3A) Variants and Clonal Hematopoiesis of Indeterminate Potential (CHIP) in Pulmonary Arterial Hypertension
Loading...
Authors
Emon, Isaac Michael
Date
2024-05-16
Type
thesis
Language
eng
Keyword
Inflammation , Epigenetics , DNA Methylation , Scleroderma , Heart Failure , Connective Tissue Disease , Associated Pulmonary Arterial Hypertension (APAH) , Hypoxia , Tet Methylcytosine Dioxygenase 2 (TET2)
Alternative Title
Abstract
Background: Mutations are found in 10-20% of idiopathic PAH (IPAH) patients, but none are consistently identified in connective tissue disease-associated PAH (APAH), which accounts for ~32% of PAH cases. TET2 mutations, a cause of clonal hematopoiesis of indeterminant potential (CHIP), predispose to an inflammatory type of PAH. Here, we examine mutations in another CHIP gene, DNMT3A, in PAH.
Methods: We analyzed the prevalence of DNMT3A variants in PAH Biobank participants (n=2572) compared to controls (GNOMAD: n=141456, SPARK: n=11198, Additional Pooled Cohort: n=3644). We used exome sequencing (ES) and panel sequencing to examine 2572 and 1659 PAH patients. We also studied DNMT3A mRNA expression in 80 PAH patients and 41 controls. Finally, we evaluated PAH development in a Dnmt3a-knockout mouse model.
Results: DNMT3A mutations were more frequent in PAH cases versus control subjects in the ES dataset (OR: 2.60). 33 PAH patients had DNMT3A variants, of whom 21/33 had APAH. While 21/33 had somatic variants (female:male 17:4), 12/33 had germline variants (female:male 11:1). Hemodynamics were comparable with and without DNMT3A variants (mPAP=58±21 vs. 52±18 mmHg). While PAH patients without DNMT3A variants had a 13.4% response rate to acute vasodilator testing, PAH patients with DNMT3A variants were unresponsive. Targeted panel sequencing identified 14.6% of PAH patients with CHIP mutations (242/1659), with DNMT3A accounting for 116/242. There was a significant association between DNMT3A CHIP (OR:25.44, p=4.50e-05) and PAH in analyses adjusted for age and sex, as well as for all CHIP variants combined (OR:23.35, p=2.87e-08). DNMT3A expression was reduced in PBMCs of PAH patients (p<0.0001). DNMT3A variants occur in 7% of all PAH patients and specifically 7.3% of APAH patients. Spontaneous PAH developed in Dnmt3a-/- mice. Dnmt3a-/- mice had increased lung macrophages and elevated plasma IL-13. The IL-1β antibody canakinumab attenuated PAH in Dnmt3a-/- mice.
Conclusions: Germline and acquired DNMT3A variants are linked to PAH in humans. DNMT3A mRNA expression is reduced in PAH PBMCs. Hematopoietic depletion of Dnmt3a causes an inflammatory form of PAH in mice. DNMT3A is a putative APAH gene and may be used as a biomarker and therapeutic target.
Description
Citation
Publisher
License
Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Attribution-NonCommercial-NoDerivatives 4.0 International
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Attribution-NonCommercial-NoDerivatives 4.0 International