The ability of a mother to produce a nutritionally complete neonatal food source has provided a powerful evolutionary advantage to mammals. Milk production by mammary epithelial cells is adaptive, its release is exquisitely timed, and its own glandular stagnation with the permanent cessation of suckling triggers the cell death and tissue remodeling that enables female mammals to nurse successive progeny. Chemical and mechanical signals both play a role in this process. However, despite this duality of input, much remains unknown about the nature and function of mechanical forces in this organ. Here, we characterize the force landscape in the functionally mature gland and the capacity of luminal and basal cells to experience and exert force. We explore molecular instruments for force-sensing, in particular channel-mediated mechanotransduction, revealing increased expression of Piezo1 in mammary tissue in lactation and confirming functional expression in luminal cells. We also reveal, however, that lactation and involution proceed normally in mice with luminal-specific Piezo1 deletion. These findings support a multifaceted system of chemical and mechanical sensing in the mammary gland, and a protective redundancy that ensures continued lactational competence and offspring survival.

母亲生产营养完整的新生儿食物来源的能力为哺乳动物提供了强大的进化优势。乳腺上皮细胞产生的乳汁具有适应性，其释放时间精确，其自身的腺体停滞随着哺乳的永久停止而触发细胞死亡和组织重塑，从而使雌性哺乳动物能够哺育连续的后代。化学信号和机械信号都在此过程中发挥作用。然而，尽管输入具有这种双重性，但对该器官中机械力的性质和功能仍然知之甚少。在这里，我们描述了功能成熟腺体中的力景观以及腔细胞和基底细胞体验和施加力的能力。我们探索用于力传感的分子仪器，特别是通道介导的机械转导，揭示了哺乳期乳腺组织中Piezo1表达的增加，并确认了管腔细胞中的功能表达。然而，我们还发现，在管腔特异性Piezo1缺失的小鼠中，哺乳和复旧正常进行。这些发现支持乳腺中化学和机械传感的多方面系统，以及确保持续哺乳能力和后代存活的保护性冗余。