The adult mammary gland undergoes dynamic changes during puberty and the postnatal developmental cycle. The mammary epithelium is composed of a bilayer of outer basal, or myoepithelial, cells and inner luminal cells, the latter lineage giving rise to the milk-producing alveolar cells during pregnancy. These luminal alveolar cells undergo Stat3-mediated programmed cell death following the cessation of lactation. It is established that immune cells in the microenvironment of the gland have a role to play both in the ductal outgrowth during puberty and in the removal of dead cells and remodelling of the stroma during the process of postlactational regression. However, most studies have focussed on the role of the stromal immune cell compartment or have quantified immune cell populations in tissue extracts. Our recent development of protocols for deep imaging of the mammary gland in three dimensions (3D) has enabled the architectural relationship between immune cells and the epithelium to be examined in detail, and we have discovered a surprisingly dynamic relationship between the basal epithelium and leucocytes. Furthermore, we have observed morphological changes in the myoepithelial cells, as involution progresses, which were not revealed by previous work in 2D tissue sections and whole tissue. This dynamic architecture suggests a role for myoepithelial cells in the orderly progression of involution. We conclude that deep imaging of mammary gland and other tissues is essential for analysing complex interactions between cellular compartments.

中文翻译：

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白细胞和乳腺上皮细胞之间的动态结构相互作用。

成人乳腺在青春期和出生后发育周期经历动态变化。乳腺上皮由双层外基底细胞或肌上皮细胞和内腔细胞组成，后者谱系在怀孕期间产生产奶的肺泡细胞。这些管腔肺泡细胞在泌乳停止后经历 Stat3 介导的程序性细胞死亡。已经确定，腺体微环境中的免疫细胞在青春期的导管生长和哺乳后退化过程中去除死细胞和基质重塑中都发挥作用。然而，大多数研究都集中在基质免疫细胞区室的作用上，或者量化了组织提取物中的免疫细胞群。我们最近开发的三维 (3D) 乳腺深度成像协议使免疫细胞和上皮细胞之间的结构关系得以详细检查，并且我们发现了基底上皮细胞和白细胞之间令人惊讶的动态关系。此外，我们已经观察到肌上皮细胞的形态学变化，随着退化的进行，以前在 2D 组织切片和整个组织中的工作没有发现这些变化。这种动态结构表明肌上皮细胞在退化的有序进展中发挥作用。我们得出结论，乳腺和其他组织的深度成像对于分析细胞区室之间的复杂相互作用至关重要。