中文摘要：

各种生理学和病理学拳件导致内质网腔中未折叠或错误折叠蛋白质的积累，引发内质网应激．通过RNA深度测序，我们发现内质网应激胁迫下，HeLa和HEK293细胞中一些microRNA的表达发生改变．通过利用实时定量PCR技术，我们进一步验证了在这些细胞中hsa—miR-423—5p的表达上调，而hsa—miR-221—3p和hsa—miR-452—5p的表达下调．荧光素酶活性检测和Western blotting实验证实CDKN1A是hsa—miR-423-5p的靶基因，而CDKN1B是hsa—miR-221-3p和hsa—miR-452—5p的靶基因．我们推测microRNA通过调控它们的靶基因，在内质网应激的适应性反应中协同作用．

英文摘要：

MicroRNAs, a class of small noncoding RNAs, play key roles in diverse biological and pathological processes. ER stress, resulting from the accumulation of unfolded or misfolded proteins in the ER lumen, is triggered by various physiological events and pathological insults. Here, using RNA deep sequencing analysis, we found that the expression of some microRNAs was altered in HeLa and HEK293 cells under ER stress. Protein and RNA levels of DGCR8, Drosha, Exportin-5, Dicer, and Ago2 showed no significant alteration in ER-stressed cells, which suggested that the change in microRNA expression might not be caused by the microRNA biogenesis pathway but by other, unknown factors. Real-time PCR assays confirmed that hsa-miR-423-5p was up-regulated, whereas hsa-miR-221-3p and hsa-miR-452-5p were down-regulated, in both HeLa and HEK293 cells under ER stress. Luciferase activity and Western blot assays verified that CDKN1A was a direct target of hsa-miR-423-5p and that CDKN1B was a direct target of hsa-miR-221-3p and hsamiR-452-5p. We speculated that by regulating their targets, microRNAs might function cooperatively as regulators in the adaptive response to ER stress.