Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin, 150070, PR China; Key Laboratory of Freshwater Aquatic Biotechnology and Breeding, Ministry of Agriculture and Rural Affairs, Harbin, PR China.
College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China.
Fish Shellfish Immunol. 2022 Jan;120:353-359. doi: 10.1016/j.fsi.2021.12.006. Epub 2021 Dec 10.
Cadmium (Cd) is an environmental pollutant produced by industrial activities, which has no known physiological benefits to organisms. In our previous study, the transcriptomic profiles of carp head kidney exposed to Cd was analyzed by genomics technique, and confirmed that miRNAs are important in the head kidney injury of carp induced by Cd, but the specific biological mechanism was unclear. In order to further explore the effect of Cd on carp head kidney lymphocyte damage, we established a model of Cd exposure in vitro. The results showed that Cd could increase the expression of Bax (Bcl-2 associated X protein), Caspase9 (Cysteinyl aspartate specific proteinase 9) and Caspase3 (Cysteinyl aspartate specific proteinase 3), inhibit the expression of Bcl-2 (B cell lymphoma/leukemia 2), and induce apoptosis of carp head kidney lymphocytes. In our previous study, we screened the differentially expressed miRNA in Cd-treated lymphocytes by high-throughput sequencing, and found that there was a significant difference in the expression of miR-9-5p. The expression trend of miR-9-5p in the vitro model was the same as that of high-throughput sequencing. We screened the differentially expressed gene FKBP5 (FK506-binding protein 51) in lymphocytes treated with Cd. It was confirmed by double luciferase reporter gene analysis that FKBP5 was the target gene of miR-9-5p. We established the overexpression/knockdown model of miR-9-5p in carp head kidney lymphocyte in vitro. The results showed that miR-9-5p could inhibit the expression of FKBP5, increase the phosphorylation level of Akt, inhibit apoptosis and improve the cell survival rate in carp head kidney lymphocytes. Together, Cd could down-regulate the expression of miR-9-5p, target up-regulate the expression of FKBP5, inhibit the phosphorylation of Akt, and promote the apoptosis of carp head kidney lymphocytes through mitochondrial pathway.
镉（Cd）是一种由工业活动产生的环境污染物，对生物体没有已知的生理益处。在我们之前的研究中，通过基因组学技术分析了暴露于镉的鲤鱼头肾的转录组谱，证实了 miRNA 在镉诱导的鲤鱼头肾损伤中很重要，但具体的生物学机制尚不清楚。为了进一步探讨镉对鲤鱼头肾淋巴细胞损伤的影响，我们建立了体外镉暴露模型。结果表明，镉可以增加 Bax（Bcl-2 相关 X 蛋白）、Caspase9（半胱天冬氨酸特异性蛋白酶 9）和 Caspase3（半胱天冬氨酸特异性蛋白酶 3）的表达，抑制 Bcl-2（B 细胞淋巴瘤/白血病 2）的表达，并诱导鲤鱼头肾淋巴细胞凋亡。在我们之前的研究中，我们通过高通量测序筛选了镉处理淋巴细胞中的差异表达 miRNA，发现 miR-9-5p 的表达存在显著差异。体外模型中 miR-9-5p 的表达趋势与高通量测序结果相同。我们筛选了镉处理淋巴细胞中差异表达的 FKBP5（FK506 结合蛋白 51）基因。双荧光素酶报告基因分析证实，FKBP5 是 miR-9-5p 的靶基因。我们在体外建立了鲤鱼头肾淋巴细胞中 miR-9-5p 的过表达/敲低模型。结果表明，miR-9-5p 可以抑制 FKBP5 的表达，增加 Akt 的磷酸化水平，抑制鲤鱼头肾淋巴细胞凋亡，提高细胞存活率。综上所述，镉可以下调 miR-9-5p 的表达，靶向上调 FKBP5 的表达，抑制 Akt 的磷酸化，通过线粒体途径促进鲤鱼头肾淋巴细胞凋亡。
