Genetic and functional analyses of TBX4 reveal novel mechanisms underlying pulmonary arterial hypertension

Yu Yoshida, Keiko Uchida, Kazuki Kodo, Hironori Shibata, Yoshiyuki Furutani, Tomotaka Nakayama, Satoshi Sakai, Toshio Nakanishi, Takao Takahashi, Hiroyuki Yamagishi

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Pulmonary arterial hypertension (PAH) is a fatal disease, with approximately 10% of cases associated with genetic variants. Recent genetic studies have reported pathogenic variants in the TBX4 gene in patients with PAH, especially in patients with childhood-onset of the disease, but the pathogenesis of PAH caused by TBX4 variant has not been fully uncovered. Methods: We analysed the TBX4 gene in 75 Japanese patients with sporadic or familial PAH using a PCR-based bidirectional sequencing method. Detected variants were evaluated using in silico analyses as well as in vitro analyses including luciferase assay, immunocytochemistry and chromatin immunoprecipitation (ChIP) whether they have altered function. We also analysed the function of TBX4 using mouse embryonic lung explants with inhibition of Tbx4 expression. Results: Putative pathogenic variants were detected in three cases (4.0%). Our in vitro functional analyses revealed that TBX4 directly regulates the transcriptional activity of fibroblast growth factor 10 (FGF10), whereas the identified TBX4 variant proteins failed to activate the FGF10 gene because of disruption of nuclear localisation signal or poor DNA-binding affinity. Furthermore, ex vivo inhibition of Tbx4 resulted in insufficiency of lung morphogenesis along with specific downregulation of Tie2 and Kruppel-like factor 4 expression. Conclusion: Our results implicate variants in TBX4 as a genetic cause of PAH in a subset of the Japanese population. Variants in TBX4 may lead to PAH through insufficient lung morphogenesis by disrupting the TBX4-mediated direct regulation of FGF10 signalling and pulmonary vascular endothelial dysfunction involving PAH-related molecules.

Original languageEnglish
Pages (from-to)105-116
Number of pages12
JournalJournal of Molecular and Cellular Cardiology
Volume171
DOIs
Publication statusPublished - 2022 Oct

Keywords

  • BMP signalling
  • Loss of function
  • Pulmonary vascular bed
  • T-box
  • TGF beta signalling

ASJC Scopus subject areas

  • Molecular Biology
  • Cardiology and Cardiovascular Medicine

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