Maldonado-Velez Gabriel, Mickler Elizabeth A, Cook Todd G, Aldred Micheala A
Indiana University School of Medicine, Dept of Medical and Molecular Genetics , Indianapolis, Indiana, United States.
Indiana University School of Medicine, Dept of Medicine, Indianapolis, Indiana, United States.
Am J Respir Cell Mol Biol. 2025 Mar 19. doi: 10.1165/rcmb.2024-0459OC.
Pulmonary arterial hypertension (PAH) is a progressive vascular disease characterized by remodeling of the precapillary pulmonary arteries. Genomic variation within the T-box 4 (TBX4) transcription factor is the second most common genetic cause of PAH, and can also cause severe lung developmental disorders with neonatal PH. Currently, the effect of TBX4 loss-of-function on later stages of lung development and predisposition to lung disease, including PH, is not well understood. Therefore, we have generated conditional knockout () mice in which recombinase deletes exon 5 of within the embryonic lung mesenchyme to create a null allele. We harvested lungs from these mice at various timepoints to examine alveologenesis, vascularization, vascular remodeling, lung cellular composition, and disruption of transcriptional activity compared with control lungs. Right ventricular systolic pressure (RVSP) was measured in six-month-old mice to evaluate for PH. lungs show enlargement of airspaces, as confirmed by an increase in mean linear intercept at P14 (24.9%), P36 (31.5%), and P180 (49.6%). These lungs also show a 39.3% decrease in von Willebrand Factor-positive vessels and a 14.2% increase in vessel wall thickness. Consistent with these results, mice show a statistically significant increase of 15.7% in RVSP and 16.3% in the Fulton index. Bulk-RNA sequencing analysis revealed enrichment of pathways and genes relevant to lung alveologenesis, angiogenesis, and PH. Our results show that disruption of expression during early lung development is sufficient to disrupt postnatal lung development and circulation.
肺动脉高压（PAH）是一种进行性血管疾病，其特征是肺前毛细血管动脉重塑。T盒4（TBX4）转录因子内的基因组变异是PAH的第二大常见遗传原因，也可导致伴有新生儿肺动脉高压的严重肺发育障碍。目前，TBX4功能丧失对肺发育后期阶段以及包括肺动脉高压在内的肺部疾病易感性的影响尚不清楚。因此，我们构建了条件性敲除（cKO）小鼠，其中Cre重组酶在胚胎肺间充质内删除TBX4的外显子5以产生无效等位基因。我们在不同时间点从这些小鼠身上采集肺组织，以检查与对照肺相比的肺泡形成、血管生成、血管重塑、肺细胞组成以及转录活性的破坏情况。在6个月大的小鼠中测量右心室收缩压（RVSP）以评估肺动脉高压。cKO肺显示气腔增大，这在出生后第14天（增加24.9%）、第36天（增加31.5%）和第180天（增加49.6%）通过平均线性截距的增加得到证实。这些肺还显示血管性血友病因子阳性血管减少39.3%，血管壁厚度增加14.2%。与这些结果一致，cKO小鼠的RVSP统计学上显著增加15.7%，富尔顿指数增加16.3%。批量RNA测序分析揭示了与肺泡形成、血管生成和肺动脉高压相关的通路和基因的富集。我们的结果表明，早期肺发育过程中TBX4表达的破坏足以扰乱出生后肺发育和循环。
