Differential responsesof pulmonary vascular cells from PAH patients and controls to TNFα and the effect of the BET inhibitor JQ1
Author(s)
Type
Journal Article
Abstract
Background: Pulmonary arterial hypertension (PAH) encompasses a group of diseases characterized by raised pulmonary vascular resistance, resulting from vascular remodelling and inflammation. Bromodomain and extra-terminal (BET) proteins are required for the expression of a subset of NF-κB-induced inflammatory genes which can be inhibited by the BET mimic JQ1+. We hypothesised that JQ+ would supress TNFα-driven inflammatory responses in human pulmonary vascular cells from PAH patients. Methods: Immunohistochemical staining of human peripheral lung tissue (N = 14 PAH and N = 12 non-PAH) was performed for the BET proteins BRD2 and 4. Human pulmonary microvascular endothelial cells (HPMEC) and pulmonary artery smooth muscle cells (HPASMC) from PAH patients (N = 4) and non-PAH controls (N = 4) were stimulated with TNFα in presence or absence of JQ1+ or its inactive isomer JQ1–. IL-6 and -8 mRNA was measured by RT-qPCR and protein levels by ELISA. Chromatin immunoprecipitation analysis was performed using EZ-ChIP™ and NF-κB p65 activation determined using a TransAm kit. MTT assay was used to measure cell viability. Results: Nuclear staining of BRD2 and BRD4 was significantly (p < 0.0001) increased in the lung vascular endothelial and smooth muscle cells from PAH patients compared to controls with normal lung function. TNFα-driven IL-6 release from both HPMECs and HPASMCs was greater in PAH cells than control cells. Levels of CXCL8/IL-8 protein release was higher in PAH HPASMCs than in control cells with similar release observed in HPMECs. TNFα-induced recruitment of activated NF-κB p65 to the IL-6 and CXCL8/IL-8 promoters were similar in both cell types and between subject groups. JQ1+ suppressed TNFα-induced IL-6 and CXCL8/IL-8 release and mRNA expression to a comparable extent in control and PAH HPMECs and HPASMCs. JQ1 had a greater efficacy on IL-6 release in HPMEC and on CXCL8/IL-8 release in HPASMC. Conclusion: BET inhibition decreases TNFα driven inflammation in primary pulmonary vascular cells. The anti-inflammatory actions of JQ1 suggests distinct cell-specific regulatory control of these genes. BET proteins could be a target for future therapies for PAH.
Date Issued
2023-07-29
Online Publication Date
2023-08-21T14:38:27Z
Date Acceptance
2023-07-23
ISSN
1465-9921
Publisher
BMC
Journal / Book Title
Respiratory Research
Volume
24
Copyright Statement
© The Author(s) 2023. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
License URI
Publication Status
Published
Article Number
ARTN 193