Harnessing Cells from Human Milk; Linking Lactation to Metabolism

项目概要： 事实证明，母乳喂养可以保护母亲及其孩子在以后的生活中免受代谢疾病的影响。然而，在这方面， 母亲肥胖和糖尿病独立预测不良泌乳结果，即使在调整后， 母乳喂养支持和社会经济因素。这种关系的生理原因尚不清楚。 这项提案旨在确定哺乳与代谢之间的分子机制，其长期目标是 制定干预措施，以改善肥胖和/或糖尿病妇女的哺乳结果。 人类哺乳的调查是具有挑战性的，由于伦理和实际障碍， 处于泌乳状态的乳腺组织。人类乳源性细胞的单细胞RNA测序表明， 这些细胞与位于泌乳腺中的乳腺上皮细胞（MEC）非常相似。额外 细胞分选工作已经将乳源性MEC确定为“液体乳腺活检”， 许多关于哺乳生物学的悬而未决的问题。 此外，MEC分化和维持需要胰岛素信号传导的微妙平衡。 胰岛素受体的乳腺特异性敲除（mam-IRKO）阻断MEC分泌分化， 因此阻碍泌乳。相反，乳腺特异性表达的活性形式的胰岛素的下游， 调解人，AKT，也驱动泌乳失败。为了确定适当的干预方法， 哺乳性能，关键是要了解MEC是否对胰岛素有反应或抵抗， 高胰岛素血症肥胖妇女和饮食诱导肥胖小鼠非泌乳乳腺的研究 提示过早的胰岛素信号传导可能是这些效应的原因，通过驱动调节失调的腺体细胞， 发展该项目的目标是1。妊娠期糖尿病（GDM）对妊娠的影响 MEC祖细胞胰岛素信号传导和乳源性MEC谱和2.定义胰岛素和其他 代谢激素对MEC分泌分化和功能的影响。 将使用与BMI匹配的患有和不患有重度GDM的女性的乳汁来源的MEC来确定是否 来自GDM女性的MEC祖细胞对胰岛素有足够的反应或抵抗，并且差异 将评估MEC人群之间可能解释这些女性泌乳结果受损的差异。在 MEC发育的体内和体外模型将用于确定胰岛素作用的潜在机制 催乳素信号，这是下调mam-IRKO小鼠。脂肪因子瘦素和 还将研究脂联素对MEC发育和功能的影响。 这一建议将为未来研究肥胖和/或糖尿病与人类健康之间的其他联系提供信息。 泌乳功能障碍拟议的办法有可能打破一个恶性的代际循环， 代谢性疾病一个由乳腺生理学和妊娠期糖尿病专家组成的协作小组将 支持申请人确保这个创新项目的成功。

Project Summary: Breastfeeding has been shown to protect mothers and their children from metabolic disease later in life. However, maternal obesity and diabetes independently predict poor lactation outcomes, even after adjustments for breastfeeding support and socioeconomic factors. The physiological reasons for this relationship remain unclear. This proposal aims to identify the molecular mechanisms linking lactation to metabolism with a long-term goal of developing interventions to improve lactation outcomes in women with obesity and/or diabetes. Investigations of human lactation are challenging due to ethical and practical barriers related to accessing mammary tissue in the lactating state. Single cell RNA sequencing of human milk-derived cells has shown that these cells are remarkably similar to mammary epithelial cells (MECs) resident in the lactating gland. Additional cell sorting efforts have established milk-derived MECs as “liquid breast biopsies” which may be used to answer many outstanding questions regarding lactation biology. Furthermore, a delicate balance of insulin signaling is required for MEC differentiation and maintenance. Mammary specific knockout of the insulin receptor (mam-IRKO) blocks MEC secretory differentiation, and therefore impedes lactation. Conversely, mammary-specific expression of an active form of insulin’s downstream mediator, AKT, also drives lactation failure. In order to identify appropriate interventional approaches to improve lactation performance, it is critical to understand if MECs are responsive or resistant to insulin in the context of hyperinsulinemia. Studies of non-lactating mammary glands in women with obesity and diet-induced obese mice suggest that premature insulin signaling may be responsible for these effects, by driving dysregulated glandular development. The aims of this project are to 1. establish the effect of maternal gestational diabetes (GDM) on MEC progenitor insulin signaling and milk-derived MEC profiles and 2. define the effects of insulin and other metabolic hormones on MEC secretory differentiation and function. Milk-derived MECs of women with and without severe GDM, matching for BMI, will be utilized to determine if MEC progenitors from women with GDM are sufficiently responsive or resistant to insulin, and differences between MEC populations which may explain impaired lactation outcomes in these women will be assessed. In vivo and in vitro models of MEC development will be used to identify the mechanism underlying insulin’s effect on lactogenic prolactin signaling, which is downregulated in mam-IRKO mice. Effects of adipokines leptin and adiponectin on MEC development and function will also be investigated. This proposal will inform future efforts to investigate additional links between obesity and/or diabetes and human lactation dysfunction. The proposed approach has the potential to break a vicious intergenerational cycle of metabolic disease. A collaborative team of experts in mammary physiology and diabetes in pregnancy will support the applicant to ensure success of this innovative project.