Department of Otolaryngology/Head and Neck Surgery, The Virginia Merrill Bloedel Hearing Research Center, University of Washington School of Medicine, Seattle, WA 98195-7923, USA.
J Assoc Res Otolaryngol. 2010 Jun;11(2):203-22. doi: 10.1007/s10162-009-0206-7. Epub 2010 Feb 18.
In chickens, nonsensory supporting cells divide and regenerate auditory hair cells after injury. Anatomical evidence suggests that supporting cells can also transdifferentiate into hair cells without dividing. In this study, we characterized an organ culture model to study auditory hair cell regeneration, and we used these cultures to test if direct transdifferentiation alone can lead to significant hair cell regeneration. Control cultures (organs from posthatch chickens maintained without streptomycin) showed complete hair cell loss in the proximal (high-frequency) region by 5 days. In contrast, a 2-day treatment with streptomycin induced loss of hair cells from all regions by 3 days. Hair cell regeneration proceeded in culture, with the time course of supporting cell division and hair cell differentiation generally resembling in vivo patterns. The degree of supporting cell division depended upon the presence of streptomycin, the epithelial region, the type of culture media, and serum concentration. On average, 87% of the regenerated hair cells lacked the cell division marker BrdU despite its continuous presence, suggesting that most hair cells were regenerated via direct transdifferentiation. Addition of the DNA polymerase inhibitor aphidicolin to culture media prevented supporting cell division, but numerous hair cells were regenerated nonetheless. These hair cells showed signs of functional maturation, including stereociliary bundles and rapid uptake of FM1-43. These observations demonstrate that direct transdifferentiation is a significant mechanism of hair cell regeneration in the chicken auditory after streptomycin damage in vitro.
在鸡中，非感觉支持细胞在受伤后会分裂并再生听觉毛细胞。解剖学证据表明，支持细胞也可以不分裂而转分化为毛细胞。在这项研究中，我们描述了一种器官培养模型，以研究听觉毛细胞的再生，并用这些培养物来测试直接转分化是否可以导致显著的毛细胞再生。对照培养物（来自孵化后未用链霉素处理的鸡的器官）在第 5 天近端（高频）区域的毛细胞完全丢失。相比之下，用链霉素处理 2 天导致所有区域的毛细胞在 3 天内丢失。在培养物中进行了毛细胞再生，支持细胞分裂和毛细胞分化的时间过程通常与体内模式相似。支持细胞分裂的程度取决于链霉素的存在、上皮区域、培养物介质的类型和血清浓度。平均而言，尽管连续存在 BrdU，但再生的毛细胞中有 87%缺乏细胞分裂标记物 BrdU，这表明大多数毛细胞是通过直接转分化再生的。在培养基中添加 DNA 聚合酶抑制剂阿非迪霉素可阻止支持细胞分裂，但仍有大量毛细胞再生。这些毛细胞表现出功能成熟的迹象，包括纤毛束和 FM1-43 的快速摄取。这些观察结果表明，在体外链霉素损伤后，直接转分化是鸡听觉中支持细胞再生的重要机制。
