F32 Fellowship for Study of Hedgehog Signaling in Postnatal Lung

描述(申请人提供)：这是一份为期两年的F32奖学金资助申请。在团契期间，申请者将致力于阐明Hedgehog(HH)信号在出生后肺发育中的作用。HH信号是由三种相似的蛋白质(Sonic、India和Desert HH)作用于细胞受体补丁，典型地影响间充质细胞的功能。Hedgehog信号在胚胎发育过程中起关键作用已经有一段时间了，但直到最近才开始意识到HH信号影响癌症和纤维化等疾病过程。Hedgehog信号在胚胎肺发育的分支形态发生中起主要作用，但目前尚不清楚该途径在肺的最后发育阶段中起什么作用。这是肺发育的最后一个出生后阶段，包括次级隔膜的形成，以及这些隔壁的成熟，这是一个鲜为人知的过程，涉及间质细胞的丧失。也有人推测，在肺纤维化中，HH等发育途径被重新激活。这项研究计划旨在检验一种假设，即适当的HH信号下调时间对于隔壁的适当成熟至关重要。该假说认为，出生后早期肺发育中的HH信号支持间充质细胞的旺盛扩张，而在肺泡化阶段结束时信号的撤销导致间充质细胞的相对损失，这是由于增殖减少和凋亡增加的某种组合。对此进行测试的目的包括：首先，详细分析这一时期HH信号的精确时间，使用读取HH信号的报告小鼠进行测量，通过qRT-PCR测量HH信号的下游转录靶标，如Gli1，以及直接测量Shh蛋白水平。此外，在第二个目标中，将确定在两个阶段增强或抑制HH信号的效果，并与基于假设的预测进行比较。为了从事这项工作和培训，申请者将在纽约大学细胞生物学代理主席Dan Rifkin博士的基础科学实验室工作，他有很好的指导记录和广泛的研究兴趣(癌症、纤维化和肺、心脏和骨骼的发育)，这些研究以细胞外基质生物学为共同线索。他还将继续进行细胞生物学、发育系统和干细胞生物学的研究生水平课程工作，以及与拨款撰写、陈述技能和研究道德行为相关的重点工作。这项研究经验和相关培训旨在增强他先前在肺纤维化方面的广泛研究经验，使他能够随时研究肺发育、肺纤维化和损伤以及发育信号通路在成人肺过程和疾病中的参与问题。

DESCRIPTION (provided by applicant): This is an application for F32 fellowship support for two years. During the fellowship period, the applicant will work on elucidating the role of Hedgehog (Hh) signaling in postnatal lung development. Hh signaling is mediated by three similar proteins (Sonic, Indian and Desert Hh) acting on the cell receptor Patched, and typically affects function of mesenchymal cells. Hedgehog signaling has been known for some time to be critical during embryonic development, but only recently has it come to be appreciated that Hh signaling affects disease processes such as cancer and fibrosis. Hedgehog signaling plays a major in branching morphogenesis in embryonic lung development but it is currently unknown what role this pathway plays during the final developmental steps of the lung. This final, postnatal phase of lung development involves creation of secondary septa, and maturation of these septal walls in a poorly understood process involving loss of interstitial cells. It is also postulated that developmental pathways such as Hh are reactivated in pulmonary fibrosis. The research plan is designed to test the hypothesis that proper timing of Hh signaling down-regulation is critical for the proper maturation of septal walls. The hypothesis states that Hh signaling in early postnatal lung development supports vigorous expansion of mesenchymal cells, whereas withdrawal of signaling at the end of the alveolarization phase contributes to a relative loss of mesenchymal cells due to some combination of reduced proliferation and increased apoptosis. The Aims to test this consist of, first, detailed analysis of the precise timig of Hh signaling during this period, measured using reporter mice that read-out Hh signaling, measurement by qRT-PCR of downstream transcriptional targets of Hh signaling such as Gli1, and direct measurement of Shh protein levels. In addition, in the second Aim, the effects of augmenting or inhibiting Hh signaling during the two phases will be determined and compared with predictions based on the hypothesis. To pursue this work and training, the applicant will work in the basic science lab of Dr. Dan Rifkin, acting chair of Cell Biology at NYU, who has a strong mentoring record and a wide range of research interests (cancer, fibrosis, and development of lung, heart and bone) that have extracellular matrix biology as a common thread. He will also pursue graduate level course work in Cell Biology, developmental systems, and stem cell biology, along with focused work related to grant writing, presentation skills and the ethical conduct of research. This research experience and related training are designed to augment his prior extensive research experience in pulmonary fibrosis and leave him poised to investigate questions of lung development, lung fibrosis and injury, and the involvement of developmental signaling pathways in adult lung processes and disease.