近日,国际权威杂志《细胞凋亡》Apoptosis(IF:4.397 2010)上刊登了华南农业大学、华南师范大学、意大利伊苏布利亚大学、广东省农业科学院等机构的研究人员的最新研究成果“Autophagy precedes apoptosis during the remodeling of silkworm larval midgut”,来自华南农业大学的曹阳教授、华南师范大学的冯启理教授以及意大利伊苏布利亚大学的Tettamanti G 博士为这篇文章的共同通讯作者。
细胞程序性死亡(PCD),包括细胞自噬(autophagy)和凋亡(apoptosis)是广泛存在于真核生物的生命现象,是近年来备受重视的研究领域之一。目前对自噬和凋亡机制参与哺乳动物、酵母和果蝇细胞的生长发育、分化及对环境应激的响应已经有较深入的认识,但对鳞翅目昆虫在变态发育进程中细胞自噬和凋亡的研究还非常欠缺。
从2004年开始,曹阳教授课题组便与Tettamanti G 博士课题组和冯启理教授课题组开展合作,对家蚕(Bombyx mori)变态期的幼虫中肠和丝腺细胞的自噬和凋亡进行了比较系统深入的研究。通过细胞生物学和分子生物学的大量证据,曾合作发表了多篇研究论文。
在这篇文章中,研究人员通过充分的细胞生物学、免疫学和分子生物学试验证据揭示,在家蚕变态期的蜕皮激素(20E)诱导下,幼虫中肠组织退化的细胞自噬先于凋亡,前者启动于熟蚕期,活跃于吐丝和预蛹时期,用以提供停食的营养再利用,后者启动于化蛹初期,并持续于整个化蛹变态时期,是细胞死亡的主要执行者。
新研究为帮助研究人员更深入了解鳞翅目昆虫在变态发育进程中细胞自噬和凋亡的机制提供了重要的研究数据。(生物谷Bioon.com)
doi:10.1007/s10495-011-0675-0
PMC:
PMID:
Autophagy precedes apoptosis during the remodeling of silkworm larval midgut
Eleonora Franzetti, Zhi-Jun Huang, Yan-Xia Shi, Kun Xie, Xiao-Juan Deng, Jian-Ping Li, Qing-Rong Li, Wan-Ying Yang, Wen-Nian Zeng and Morena Casartelli, et al.
Although several features of apoptosis and autophagy have been reported in the larval organs of Lepidoptera during metamorphosis, solid experimental evidence for autophagy is still lacking. Moreover, the role of the two processes and the nature of their relationship are still cryptic. In this study, we perform a cellular, biochemical and molecular analysis of the degeneration process that occurs in the larval midgut of Bombyx mori during larval–adult transformation, with the aim to analyze autophagy and apoptosis in cells that die under physiological conditions. We demonstrate that larval midgut degradation is due to the concerted action of the two mechanisms, which occur at different times and have different functions. Autophagy is activated from the wandering stage and reaches a high level of activity during the spinning and prepupal stages, as demonstrated by specific autophagic markers. Our data show that the process of autophagy can recycle molecules from the degenerating cells and supply nutrients to the animal during the non-feeding period. Apoptosis intervenes later. In fact, although genes encoding caspases are transcribed at the end of the larval period, the activity of these proteases is not appreciable until the second day of spinning and apoptotic features are observable from prepupal phase. The abundance of apoptotic features during the pupal phase, when the majority of the cells die, indicates that apoptosis is actually responsible for cell death and for the disappearance of larval midgut cells.