Mammary organoid (MaO) models are only available for a few traditional model organisms, limiting our ability to investigate mammary gland development and cancer across the diverse taxa of mammals. For example, horses are mammals with a similar mammary anatomy and function as humans, but they have a remarkably low incidence of mammary cancer, making the development of MaOs in non-traditional model organisms attractive, particularly in comparative cancer research. This study established equine mammary organoids (EqMaOs) from mammary gland tissue fragments and evaluated parameters including diameter, budding, and growth stage in non-budding EqMaOs, in cultures with increasing concentrations of epidermal growth factor (EGF), a key growth factor implicated in mammary gland development. Our findings showed that EqMaO diameter is not influenced by EGF concentration, whereas number of EqMaOs with budding and stage in non-budding EqMaOs are positively influenced by increasing EGF concentration. EqMaOs also formed protrusions with putative functions, including organoid fusion and sensory functions. We further characterized EqMaOs by the presence of myoepithelial and luminal cells using immunohistochemistry and used the hormone prolactin to stimulate milk secretion, as illustrated by β-lactoglobulin expression, in these EqMaOs. Additionally, we showed that our method to establish MaOs is widely applicable to additional non-traditional mammalian model organisms such as cat, pig, deer, rabbit, and prairie vole. Collectively, MaO models across species will be a useful tool for comparative developmental and cancer studies.

中文翻译：

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非传统模式生物的乳类类器官的建立和表征

乳腺类器官（MaO）模型仅适用于一些传统的模型生物，从而限制了我们研究哺乳动物多种类群的乳腺发育和癌症的能力。例如，马是具有与人类相似的乳房解剖结构和功能的哺乳动物，但是它们的乳腺癌发病率非常低，这使得在非传统模型生物中MaOs的发展具有吸引力，尤其是在比较癌症研究中。这项研究从乳腺组织碎片中建立了马乳腺类器官（EqMaOs），并评估了在表皮生长因子（EGF）浓度增加的培养物中非萌芽EqMaOs的直径，萌芽和生长阶段等参数。乳腺发育。我们的研究结果表明，EqMaO的直径不受EGF浓度的影响，而E萌芽期的EqMaOs数量不受EGF浓度的增加正影响。EqMaOs还形成具有推定功能的突起，包括类器官融合和感觉功能。我们使用免疫组织化学进一步通过肌上皮和腔细胞的存在来表征EqMaO，并在这些EqMaO中使用催乳激素刺激乳汁分泌，如β-乳球蛋白的表达所示。此外，我们证明了我们建立MaO的方法可广泛应用于其他非传统的哺乳动物模型生物，例如猫，猪，鹿，兔和草原田鼠。总的来说，跨物种的MaO模型将是比较发展和癌症研究的有用工具。EGF浓度的增加对非萌芽的EqMaOs的萌芽和阶段数产生正向影响。EqMaOs还形成具有推定功能的突起，包括类器官融合和感觉功能。我们使用免疫组织化学进一步通过肌上皮和腔细胞的存在来表征EqMaO，并在这些EqMaO中使用催乳激素刺激乳汁分泌，如β-乳球蛋白的表达所示。此外，我们证明了我们建立MaO的方法可广泛应用于其他非传统的哺乳动物模型生物，例如猫，猪，鹿，兔和草原田鼠。总的来说，跨物种的MaO模型将是比较发展和癌症研究的有用工具。EGF浓度的增加对非萌芽的EqMaOs的萌芽和阶段数产生正向影响。EqMaOs还形成具有推定功能的突起，包括类器官融合和感觉功能。我们使用免疫组织化学进一步通过肌上皮和腔细胞的存在来表征EqMaO，并在这些EqMaO中使用催乳激素刺激乳汁分泌，如β-乳球蛋白的表达所示。此外，我们证明了我们建立MaO的方法可广泛应用于其他非传统的哺乳动物模型生物，例如猫，猪，鹿，兔和草原田鼠。总的来说，跨物种的MaO模型将是比较发展和癌症研究的有用工具。