Laboratory of Crustacean Development Biology and Macrobenthic Ecology, School of Life Science, East China Normal University, Shanghai, 200241, China.
Laboratory of Crustacean Development Biology and Macrobenthic Ecology, School of Life Science, East China Normal University, Shanghai, 200241, China.
Aquat Toxicol. 2020 Mar;220:105420. doi: 10.1016/j.aquatox.2020.105420. Epub 2020 Jan 20.
Recently, research on the biological effects of nanoplastics has grown exponentially. However, studies on the effects of nanoplastics on freshwater organisms and the mechanisms of the biological effects of nanoplastics are limited. In this study, the content of reactive oxygen species (ROS), gene and protein expression in the MAPK-HIF-1/NFkB pathway, and antioxidant gene expressions and enzyme activities were measured in Daphnia pulex exposed to polystyrene nanoplastic. In addition, the full-length extracellular signal-regulated kinases (ERK) gene, which plays an important role in the MAPK pathway, was cloned in D. pulex, and the amino acid sequence, function domain, and phylogenetic tree were analyzed. The results show that nanoplastic caused the overproduction of ROS along with other dose-dependent effects. Low nanoplastic concentrations (0.1 and/or 0.5 mg/L) significantly increased the expressions of genes of the MAPK pathway (ERK; p38 mitogen-activated protein kinases, p38; c-Jun amino-terminal kinases, JNK; and protein kinase B, AKT), HIF-1 pathway (prolyl hydroxylasedomain, PHD; vascular endothelial growth factor, VEGF; glucose transporter, GLUT; pyruvate kinase M, PKM; hypoxia-inducible factor 1, HIF1), and CuZn superoxide dismutase (SOD) along with the activity of glutathione-S-transferase. As the nanoplastic concentration increased, these indicators were significantly suppressed. The protein expression ratio of ERK, JNK, AKT, HIF1α, and NFkBp65 (nuclear transcription factor-kB p65) as well as the phosphorylation of ERK and NFkBp65 were increased in a dose-dependent manner. The activities of other antioxidant enzymes (catalase, total SOD, and CuZn SOD) were significantly decreased upon exposure to nanoplastic. Combined with our previous work, these results suggest that polystyrene nanoplastic causes the overproduction of ROS and activates the downstream pathway, resulting in inhibited growth, development, and reproduction. The present study fosters a better understanding of the biological effects of nanoplastics on zooplankton.
最近，纳米塑料的生物效应研究呈指数级增长。然而，关于纳米塑料对淡水生物的影响以及纳米塑料生物效应的机制的研究还很有限。在本研究中，研究了聚碳酸酯纳米塑料暴露对大型溞（Daphnia pulex）中活性氧（ROS）含量、MAPK-HIF-1/NFkB 通路中基因和蛋白质表达、抗氧化基因表达和酶活性的影响。此外，克隆了在 MAPK 通路中起重要作用的全长细胞外信号调节激酶（ERK）基因，并对其氨基酸序列、功能域和系统发育树进行了分析。结果表明，纳米塑料导致 ROS 的过度产生，并伴有其他剂量依赖性效应。低浓度纳米塑料（0.1 和/或 0.5mg/L）显著增加了 MAPK 通路（ERK；p38 丝裂原活化蛋白激酶，p38；c-Jun 氨基末端激酶，JNK；蛋白激酶 B，AKT）、HIF-1 通路（脯氨酰羟化酶，PHD；血管内皮生长因子，VEGF；葡萄糖转运蛋白，GLUT；丙酮酸激酶 M，PKM；缺氧诱导因子 1，HIF1）和 CuZn 超氧化物歧化酶（SOD）的基因表达，以及谷胱甘肽-S-转移酶的活性。随着纳米塑料浓度的增加，这些指标均受到显著抑制。ERK、JNK、AKT、HIF1α 和 NFkBp65（核转录因子-kB p65）的蛋白表达比值以及 ERK 和 NFkBp65 的磷酸化水平呈剂量依赖性增加。纳米塑料暴露后，其他抗氧化酶（过氧化氢酶、总 SOD 和 CuZn SOD）的活性显著降低。结合我们之前的工作，这些结果表明，聚碳酸酯纳米塑料导致 ROS 的过度产生，并激活下游通路，从而抑制生长、发育和繁殖。本研究增进了对浮游动物纳米塑料生物效应的理解。
