Although several cell culture systems have been developed to investigate the function of the mammary gland in dairy livestock, they have potential limitations, such as the loss of alveolar structure or genetic and phenotypic differences from their native counterparts. Overcoming these challenges is crucial for lactation research. Development of protocols to establish lactating organoid of livestock represents a promising goal for the future. In this study, we developed a protocol to establish a culture system for mammary organoids in dairy goats to model the mammary gland development and lactation process. The organoids cultured within an extracellular matrix gel maintained a bilayer structure that closely resembled the native architecture of mammary tissue. The expansion of mammary organoids was significantly promoted by growth factors containing epidermal growth factor and fibroblast growth factor 2 whereas the proliferative index of the organoids was significantly inhibited by the treatment with WNT inhibitors. Upon stimulation with a lactogenic medium containing prolactin, the mammary organoids exhibited efficient lactation, characterized by the accumulation of lipid droplets in the lumen space. The lactation could be sustained for more than 3 weeks. Importantly, the expression patterns of genes related to fatty acid synthesis and milk proteins in lactating organoids closely mirrored those observed in mammary tissues. These observations were confirmed by data from proteomic analysis that the bulk of milk proteins was produced in the lactating organoids. This study is the first to establish a mammary organoid culture system modeling the mammary gland development and lactation process in ruminants. The efficient induction of lactation in ruminant mammary organoids holds promises for advancing the field of cell-based milk bio-manufacture in the food industry.

中文翻译：

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建立模拟乳腺发育和哺乳的山羊乳腺类器官培养物


尽管已经开发了几种细胞培养系统来研究奶牛乳腺的功能，但它们具有潜在的局限性，例如肺泡结构的丧失或与天然对应物的遗传和表型差异。克服这些挑战对于哺乳研究至关重要。开发建立牲畜泌乳类器官的方案是未来一个有希望的目标。在这项研究中，我们开发了一个方案来建立奶山羊乳腺类器官的培养系统，以模拟乳腺发育和泌乳过程。在细胞外基质凝胶中培养的类器官保持双层结构，与乳腺组织的天然结构非常相似。含有表皮生长因子和成纤维细胞生长因子2的生长因子显着促进乳腺类器官的扩张，而WNT抑制剂的治疗显着抑制类器官的增殖指数。在用含有催乳素的催乳培养基刺激后，乳腺类器官表现出有效的泌乳能力，其特征是脂滴在腔内积聚。哺乳期可维持3周以上。重要的是，泌乳类器官中与脂肪酸合成和乳蛋白相关的基因的表达模式与乳腺组织中观察到的表达模式非常相似。蛋白质组学分析的数据证实了这些观察结果，即大部分乳蛋白是在泌乳类器官中产生的。本研究首次建立了模拟反刍动物乳腺发育和泌乳过程的乳腺类器官培养系统。 反刍动物乳腺类器官有效诱导泌乳有望推动食品工业中基于细胞的牛奶生物制造领域的发展。