Yang Jun, Joshi Sonali, Wang Qingfei, Li Ping, Wang Hai, Xiong Yan, Xiao Yi, Wang Jinyang, Parker-Thornburg Jan, Behringer Richard R, Yu Dihua
Department of Molecular and Cellular Oncology, Unit 108, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030 USA.
University of Texas Health Science Center Graduate School of Biomedical Sciences, Cancer Biology Program, Houston, TX 77030 USA.
Cell Biosci. 2017 Nov 2;7:58. doi: 10.1186/s13578-017-0186-y. eCollection 2017.
The 14-3-3 family of proteins have been reported to play an important role in development in various mouse models, but the context specific developmental functions of 14-3-3ζ remain to be determined. In this study, we identified a context specific developmental function of 14-3-3ζ.
Targeted deletion of 14-3-3ζ in the C57Bl/6J murine genetic background led to neonatal lethality due to respiratory distress and could be rescued by out-breeding to the CD-1 or backcrossing to the FVB/NJ congenic background. Histological analysis of lung sections from 18.5 days post coitum embryos (dpc) showed that 14-3-3ζ-/- lung development is arrested at the pseudoglandular stage and exhibits vascular defects. The expression of miR-126, an endothelial-specific miRNA known to regulate lung vascular integrity was down-regulated in the lungs of the 14-3-3ζ-/- embryos in the C57Bl/6J background as compared to their wild-type counterparts. Loss of 14-3-3ζ in endothelial cells inhibited the angiogenic capability of the endothelial cells as determined by both trans-well migration assays and tube formation assays and these defects could be rescued by re-expressing miR-126. Mechanistically, loss of 14-3-3ζ led to reduced Erk1/2 phosphorylation resulting in attenuated binding of the transcription factor Ets2 on the miR-126 promoter which ultimately reduced expression of miR-126.
Our data demonstrates that miR-126 is an important angiogenesis regulator that functions downstream of 14-3-3ζ and downregulation of miR-126 plays a critical role in 14-3-3ζ-loss induced defects in lung vasculature in the C57Bl/6J genetic background.
据报道，14-3-3蛋白家族在各种小鼠模型的发育中发挥重要作用，但14-3-3ζ在特定背景下的发育功能仍有待确定。在本研究中，我们确定了14-3-3ζ在特定背景下的发育功能。
在C57Bl/6J小鼠遗传背景中靶向缺失14-3-3ζ会导致新生儿因呼吸窘迫而死亡，通过与CD-1杂交或回交至FVB/NJ同源背景可挽救该致死性。对妊娠18.5天胚胎（dpc）的肺切片进行组织学分析表明，14-3-3ζ基因敲除小鼠的肺发育停滞在假腺期，并表现出血管缺陷。与野生型对照相比，在C57Bl/6J背景下的14-3-3ζ基因敲除胚胎的肺中，已知调节肺血管完整性的内皮特异性miRNA miR-126的表达下调。通过trans-well迁移试验和管形成试验确定，内皮细胞中14-3-3ζ的缺失抑制了内皮细胞的血管生成能力，重新表达miR-126可挽救这些缺陷。机制上，14-3-3ζ的缺失导致Erk1/2磷酸化减少，导致转录因子Ets2与miR-126启动子的结合减弱，最终降低了miR-126的表达。
我们的数据表明，miR-126是一种重要的血管生成调节因子，在14-3-3ζ下游发挥作用，miR-126的下调在C57Bl/6J遗传背景下14-3-3ζ缺失诱导的肺血管缺陷中起关键作用。
