Author + information
- Saurabhkumar C. Patel,
- Tianji Chen,
- Miranda Sun,
- Ram Ramchandran and
- Usha Raj
Purpose: MicroRNAs (miRNAs) are post-transcriptional gene regulators involved in a wide range of biological processes including angiogenesis. Bronchopulmonary dysplasia (BPD), also known as “arrested lung development”, is characterized by decreased lung vascularization and simplified alveolarization. However, our knowledge about the role of miRNAs in BPD is very limited. The purpose of this study is to identify miRNAs that contribute to the decreased vascularization in BPD and to investigate the mechanisms involved.
Methods: Newborn mice were exposed to hyperoxia (75% O2) for 2 weeks to induce BPD. To identify miRNAs that contribute to the decreased vascularization in BPD, we performed miRNA qRT-PCR array (LC Sciences) using harvested lung tissue from hyperoxic and normoxic (control) mouse lungs. The data was validated by qRT-PCR. To determine which miRNAs were involved in lung capillary formation, we transfected human pulmonary artery endothelial cells (HPAEC) with mimics for selected miRNA candidates. 24 hours after transfection, cells were re-plated on Matrigel and exposed to 95 % hyperoxia and normoxia to assay for tube formation. Tube formation was measured manually for loops and branching, 24 hours after re-plating the cells. We also measured the expression of known lung angiogenic factors (VEGF, EPO, PDGF-BB, EDN) by qRT-PCR.
Results: The miRNA qPCR array data showed that miR-133a and miR-133b were decreased in hyperoxic lungs to 0.59 and 0.54 of the values in normoxic lungs. The results were validated by qRT-PCR. We found that inducing the expression of miR-133a and miR-133b with miRNA mimics restored hyperoxia-suppressed loop formation and branching in HPAEC. Induced miR-133 expression with miRNA mimics also induced the expression of angiogenic factors VEGF, EPO, PDGF-BB, EDN.
Conclusions: Our results suggest that decreased miR-133a and miR-133b levels in hyperoxic lungs contribute to the decreased vascularization in BPD.
Grants: NHLBI 1R01HL123804 (Raj PI)
Poster Hall, Hall C
Friday, March 17, 2017, 10:00 a.m.-10:45 a.m.
Session Title: MicroRNAs and Beyond in Vascular Medicine
Abstract Category: 38. Vascular Medicine: Basic
Presentation Number: 1127-358
- 2017 American College of Cardiology Foundation