Vesicle trafficking plays a novel role in erythroblast enucleation
Vesicle trafficking plays a novel role in erythroblast enucleation
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DOI：
10.1182/blood-2010-03-277426
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发表时间：
2010-10-28
期刊：
影响因子：
20.3
通讯作者：
Crispino, John D.
中科院分区：
文献类型：
--
作者：
Keerthivasan, Ganesan;Small, Sara;Crispino, John D.
哺乳动物红细胞去核是一个机制在很大程度上尚不清楚的过程。流行的模型认为，核挤出是通过不对称的胞质分裂发生的。为了验证这一假说，我们用胞质分裂抑制剂处理原始红细胞，包括灯盏花素、橙皮素和诺可达唑，然后检测去核情况。虽然这些药物在培养早期加入时会抑制细胞周期进展和随后的去核，但当加入有丝分裂后细胞时，它们无法阻止适当的去核。这些结果表明，肌动球蛋白环的收缩不是核排出所必需的。下一步，通过对初级红细胞的超微结构检查，我们观察到在挤出核近端的细胞质中有空泡聚集。这一发现使我们假设，囊泡运输有助于红细胞去核。在这里，我们表明，囊泡运输的化学抑制剂阻止原代红细胞的去核，而不影响分化、细胞分裂或凋亡。此外，击倒网状蛋白可抑制晚期红细胞的去核作用。相比之下，空泡素-1，一种诱导空泡形成的小分子，增加了去核细胞的比例。综上所述，这些结果表明，囊泡的运输，特别是胞核和胞浆交界处空泡的形成、移动和随后的融合，是哺乳动物红细胞去核的关键组成部分。(血。2010；116(17)：3331-3340)
Enucleation of mammalian erythroblasts is a process whose mechanism is largely undefined. The prevailing model suggests that nuclear extrusion occurs via asymmetric cytokinesis. To test this hypothesis, we treated primary erythroblasts with inhibitors of cytokinesis, including blebbistatin, hesperadin, and nocodazole, and then assayed for enucleation. Although these agents inhibited cell-cycle progression and subsequent enucleation when added early in culture, they failed to block enucleation proper when added to postmitotic cells. These results suggest that contraction of the actomyosin ring is not essential for nuclear expulsion. Next, by ultrastructural examination of primary erythroblasts, we observed an accumulation of vacuoles in the cytoplasm proximal to the extruding nucleus. This finding led us to hypothesize that vesicle trafficking contributes to erythroblast enucleation. Here, we show that chemical inhibitors of vesicle trafficking block enucleation of primary erythroblasts without affecting differentiation, cell division, or apoptosis. Moreover, knock-down of clathrin inhibited the enucleation of late erythroblasts. In contrast, vacuolin-1, a small molecule that induces vacuole formation, increased the percentage of enucleated cells. Together, these results illustrate that vesicle trafficking, specifically the formation, movement, and subsequent coalescence of vacuoles at the junction of the nucleus and the cytoplasm, is a critical component of mammalian erythroblast enucleation. ( Blood. 2010; 116(17): 3331-3340)