Granger Joly de Boissel Philippine, Fournier Michel, Rodriguez-Lecompte Juan Carlos, McKenna Patty, Kibenge Frederick, Siah Ahmed
Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada.
INRS - Institut Armand-Frappier, Université du Québec, 531 boulevard des Prairies, Laval, QC H7V 1B7, Canada.
Fish Shellfish Immunol. 2017 Aug;67:575-585. doi: 10.1016/j.fsi.2017.06.001. Epub 2017 Jun 6.
The bivalve mollusk, Mytilus edulis, is used as a sentinel species in several monitoring programs due to its ability to bio-accumulate contaminants. Its immune system consists of hemocytes and humoral components, which constitute the main part of the hemolymph. The present study is aimed at understanding the effects of Cd on the differentially expressed genes involved in the phagocytosis of M. edulis' hemocytes. Our approach focuses on an in vitro model by exposing hemocytes to different concentrations of Cd ranging from 10 M to 10 M. Phagocytosis and cell viability as functional markers were measured using flow cytometry. The molecular mechanisms regulated by Cd were investigated using RNA-seq and DGE analysis. Results showed that viability and phagocytosis of hemocytes exposed to 10 M of Cd were significantly decreased after 21 h of exposure. RNA sequencing data showed that 1112 transcripts (out of 352,976 contigs) were differentially regulated by the highest concentration of Cd. Among these identified transcripts, 1028 and 84 were up and down-regulated respectively. The induction of super oxide dismutase (SOD), glutathion-s-transferase (GST), cytochrome P450 2C8 (CYP2C8), multidrug resistance protein (MRP1) and heat shock protein 70 (HSP70) suggests that Cd can regulate key molecular mechanisms. In addition, several toll-like receptors (TLR) as well as genes involved in phagocytosis (actin and CDC42) and apoptosis (caspase 8 and XIAP/IAP) were induced by Cd. Thus, our model highlights the effect of Cd on the phagocytic function of M. edulis' hemocytes along with the regulation of gene expression involved in innate immunity, detoxification and apoptosis. Further investigations need to be pursued to unravel the effects of Cd on the molecular mechanisms identified in this study.
双壳贝类软体动物紫贻贝，因其具有生物累积污染物的能力，在多个监测项目中被用作指示物种。其免疫系统由血细胞和体液成分组成，这些构成了血淋巴的主要部分。本研究旨在了解镉对紫贻贝血细胞吞噬作用中差异表达基因的影响。我们的方法聚焦于一个体外模型，即将血细胞暴露于浓度范围为10⁻⁶M至10⁻²M的不同镉浓度下。使用流式细胞术测量吞噬作用和细胞活力作为功能标记。利用RNA测序和差异基因表达分析研究镉调控的分子机制。结果表明，暴露于10⁻²M镉的血细胞在暴露21小时后，其活力和吞噬作用显著降低。RNA测序数据显示，在352,976个重叠群中，有1112个转录本受到最高浓度镉的差异调控。在这些鉴定出的转录本中，分别有1028个上调和84个下调。超氧化物歧化酶（SOD）、谷胱甘肽 - S - 转移酶（GST）、细胞色素P450 2C8（CYP2C8）、多药耐药蛋白（MRP1）和热休克蛋白70（HSP70）被诱导，这表明镉可以调控关键分子机制。此外，镉还诱导了几种Toll样受体（TLR）以及参与吞噬作用（肌动蛋白和CDC42）和凋亡（半胱天冬酶8和XIAP/IAP）的基因。因此，我们的模型突出了镉对紫贻贝血细胞吞噬功能的影响以及对先天免疫、解毒和凋亡相关基因表达的调控。需要进一步开展研究以阐明镉对本研究中鉴定出的分子机制的影响。
