发布: 2019年10月20日第9卷第20期 DOI: 10.21769/BioProtoc.3403 浏览次数: 6827
评审: Zinan ZhouThirupugal GovindarajanKarthik KrishnamurthyAnita Umesh
Abstract
Alveoli are the gas-exchange units of lung. The process of alveolar development, alveologenesis, is regulated by a complex network of signaling pathways that act on various cell types including alveolar type I and II epithelial cells, fibroblasts and the vascular endothelium. Dysregulated alveologenesis results in bronchopulmonary dysplasia in neonates and in adults, disrupted alveolar regeneration is associated with chronic lung diseases including COPD and pulmonary fibrosis. Therefore, visualizing alveologenesis is critical to understand lung homeostasis and for the development of effective therapies for incurable lung diseases. We have developed a technique to visualize alveologenesis in real-time using a combination of widefield microscopy and image deconvolution of precision-cut lung slices. Here, we describe this live imaging technique in step-by-step detail. This time-lapse imaging technique can be used to capture the dynamics of individual cells within tissue slices over a long time period (up to 16 h), with minimal loss of fluorescence or cell toxicity.
Keywords: Imaging alveologenesis (肺泡生成成像)Background
Prenatal and postnatal lung development is classified into several distinct stages beginning with budding from the foregut endoderm followed by branching morphogenesis, sacculation and alveologenesis within surrounding lung mesenchyme. This developmental process is tightly regulated by a well-orchestrated signaling programme and cellular components (Kotton and Morrisey, 2014; Akram et al., 2016). The major function of the lungs is gas exchange, which occurs via diffusion (Herriges and Morrisey, 2014). This diffusion takes place between the thin cellular layers of alveolar epithelium and capillary endothelium (Roth-Kleiner and Post, 2005). Dysregulated alveologenesis is linked with a number of neonatal and infant diseases, including bronchopulmonary dysplasia (BPD) and pulmonary hypoplasia (Kreiger et al., 2006; Hilgendorff et al., 2014). In adults, alveolar damage is a component of several chronic lung diseases such as chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). Currently, there are no curative treatments for these diseases other than lung transplantation (Warburton et al., 2006; Madurga et al., 2013; McGowan, 2014) and there is an unmet need to understand the mechanisms of alveologenesis in order to develop effective treatments.
In mice, sacculation begins around embryonic day 17.5 and is followed by alveologenesis, which begins within the first few days of postnatal life and is mostly completed in first month of life (Herriges and Morrisey, 2014). However, the most active phase of alveologenesis occurs in first two weeks of postnatal life with the majority of alveoli formed by postnatal day (P) 21 (Hind et al., 2002; Snoeck, 2015).
Current understanding, based on static imaging experiments, is that alveologenesis occurs through repeated septation events that sub-divide primary air sacs to increase the number and surface area of alveoli (Amy et al., 1977; Mund et al., 2008). Real-time visualization of alveologenesis is challenging due to their location deep inside the body and the relatively slow duration of this process. A recent study used both ex vivo and in vivo live-imaging to study the sacculation stage of mouse lung development, immediately prior to alveologenesis, but these techniques are not suitable for imaging postnatal lungs (Poobalasingam et al., 2017; Li et al., 2018).
Precision cut lung slices (PCLS) contain intact alveoli and are increasingly used to study lung biology and disease pathogenesis (Meng et al., 2008; Sanderson, 2011; Thornton et al., 2012). Time-lapse imaging of PCLS has been used to show dynamic interactions of mesenchymal cells and macrophages with the extracellular matrix in adult normal and fibrotic mouse lungs, as well as in PCLS of human lungs (Burgstaller et al., 2015). In addition, quantifiable ex vivo alveologenesis has been demonstrated in early postnatal mouse PCLS culture (Pieretti et al., 2014). Using a combination of widefield microscopy and image deconvolution on postnatal mouse PCLS we have developed a method to capture the morphological mechanisms of alveologenesis in real-time (Akram et al., 2019). Here we describe the detailed protocol for real-time live imaging of postnatal alveologenesis.
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文章信息
版权信息
© 2019 The Authors; exclusive licensee Bio-protocol LLC.
如何引用
Akram, K. M., Yates, L. L., Mongey, R., Rothery, S., Gaboriau, D. C. A., Sanderson, J., Hind, M., Griffiths, M. and Dean, C. H. (2019). Time-lapse Imaging of Alveologenesis in Mouse Precision-cut Lung Slices. Bio-protocol 9(20): e3403. DOI: 10.21769/BioProtoc.3403.
分类
细胞生物学 > 细胞成像 >
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