Rapid cold-hardening blocks cold-induced apoptosis by inhibiting the activation of pro-caspases in the flesh fly Sarcophaga crassipalpis
Rapid cold-hardening blocks cold-induced apoptosis by inhibiting the activation of pro-caspases in the flesh fly Sarcophaga crassipalpis
复制标题
快速冷硬化通过抑制肉蝇 Sarcophaga crassipalpis 中半胱天冬酶原的激活来阻止冷诱导的细胞凋亡
作者：
S. Yi;R. Lee
细胞凋亡在选择性消除由于各种环境应激而导致的亚致死损伤细胞中发挥着重要作用。快速冷硬化（RCH）反应可以保护昆虫免受冷休克伤害造成的致命后果。我们最近证明冷休克会诱导昆虫细胞凋亡，而 RCH 的功能是特异性阻止冷休克诱导的细胞凋亡。在本研究中，我们使用来自成年肉蝇Sarcophaga crassipalpis的分离脂肪体、中肠、肌肉和马氏小管来测试以下假设：（1）不同组织中寒冷诱导的细胞凋亡不同；（2）RCH通过阻止前半胱天冬酶的激活来阻断细胞凋亡途径。冷休克诱导大量细胞凋亡，这与使用活体染料测定的组织损伤相匹配。 RCH 治疗显着减少了所有测试组织中的细胞凋亡。冷和热休克组的 Caspase-3（刽子手）活性比对照组和 RCH 组高 2-3 倍。同样，除中肠外的所有组织中，caspase-9（引发剂）的活性都显示出与 caspase-3 相似的趋势。此外，与对照组相比，冷休克和热休克治疗还使脂肪体和肌肉提取物的可溶性部分和膜部分中的 caspase-2 活性增加了 2-3 倍。
Apoptosis plays important roles in the selective elimination of sub-lethally damaged cells due to various environmental stresses. The rapid cold-hardening (RCH) response protects insects from the otherwise lethal consequences of injury due to cold-shock. We recently demonstrated that cold shock induces apoptotic cell death in insects and that RCH functions to specifically block cold-shock-induced apoptosis. In the present study we used isolated fat body, midgut, muscle, and Malpighian tubules from adult flesh flies Sarcophaga crassipalpis to test the following hypotheses: (1) cold-induced apoptosis varies among different tissues and (2) RCH blocks the apoptotic pathway by preventing the activation of pro-caspases. Cold-shock induced substantial amounts of apoptotic cell death that matched with tissue damage as determined using vital dyes. RCH treatment significantly reduced apoptotic cell death in all tested tissues. Caspase-3 (executioner) activity was 2–3 times higher in the cold- and heat-shocked groups than in control and RCH groups. Likewise, the activity of caspase-9 (initiator) showed a similar trend as for caspase-3 in all tissues but midgut. In addition, cold-shock and heat-shock treatments also increased caspase-2 activity 2–3 folds in both soluble and membrane fractions of fat body and muscle extracts compared to controls.