Wang Yali, Gao Xiaoning, Wang Tianewi, Zhang Yangyang, Hu Kun
National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China; National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai, China; Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai Ocean University, Shanghai, China.
National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China; National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai, China; Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai Ocean University, Shanghai, China.
Dev Comp Immunol. 2025 Jan;162:105311. doi: 10.1016/j.dci.2024.105311. Epub 2024 Dec 27.
Saprolegniasis is a common fungal disease in aquaculture. It will form white flocculent hyphae on the skin of fish, and the hyphae may grow inward and penetrate into muscle tissue, which will reduce the immunity of the body and eventually lead to death. However, there are still some gaps in the mechanism of the fish body surface against the invasion of Saprolegnia. This study explored the defense mechanism of Epithelioma papulosum cyprini cell (EPC) in the process of Saprolegnia parasitica infection from the perspective of pathogenic bacteria and host cells, so as to provide a theoretical basis for further exploring the mechanism of host resistance to S. parasitica invasion. The EPC cell was used as the research object. The EPC cells were treated with 1 × 10 CFU/mL of S. parasitica for 0, 6, 12, 24, 48 and 72 h. Cell viability and cell membrane damage were detected, and the non-specific immune enzyme activity in the cells was detected. Based on the above research, the apoptosis genes and antioxidant genes in the cells were detected to analyze the effect of S. parasitica on the metabolism of the EPC cells. The results showed that with the prolongation of the co-culture time of S. parasitica and cells, the cell viability gradually decreased and the cell membrane integrity was destroyed, but at the same time, the activity of non-specific immune enzymes increased to resist the infection of S. parasitica. In addition, the detection of EPC apoptosis gene casp3a and CTSD showed that the relative content of casp3a gene increased significantly at 24 h and reached the maximum value of the culture time (P < 0.05). The content of CTSD gene increased significantly at 12 h and reached the maximum value (P < 0.05). The results of antioxidant immune genes serpinh1a and gpx1a were opposite to the structure of apoptotic genes. The content of serpinh1a and gpx1a genes decreased significantly at 12 h (P < 0.05), but with the prolongation of culture time, the content increased significantly at 24 h and 48 h (P < 0.05). After stimulation of EPC cells by S. parasitica, the differential metabolites were mainly concentrated in Lipids, Compounds with biological roles and Phytochemical compounds. The KEGG pathway mainly focused on ABC transporters, Glycerophospholipid metabolism, Cysteine and methionine metabolism, Glycine, serine and threonine metabolism, Purine metabolism. In general, S. parasitica can affect cell activity, destroy the cell membrane of EPC cells, and cause apoptosis. However, EPC cells can also resist the invasion of S. parasitica by regulating their own non-specific immunity and their own metabolites, thereby protecting the body from the infection of S. parasitica.
水霉病是水产养殖中一种常见的真菌疾病。它会在鱼的体表形成白色絮状菌丝，这些菌丝可能向内生长并侵入肌肉组织，这会降低鱼体的免疫力，最终导致死亡。然而，鱼体表抵御水霉入侵的机制仍存在一些空白。本研究从病原菌和宿主细胞的角度，探讨了鲤上皮瘤细胞（EPC）在寄生水霉感染过程中的防御机制，为进一步探究宿主抵抗寄生水霉入侵的机制提供理论依据。以EPC细胞作为研究对象。将EPC细胞用1×10⁶CFU/mL的寄生水霉处理0、6、12、24、48和72小时。检测细胞活力和细胞膜损伤情况，并检测细胞内非特异性免疫酶活性。基于上述研究，检测细胞内的凋亡基因和抗氧化基因，以分析寄生水霉对EPC细胞代谢的影响。结果表明，随着寄生水霉与细胞共培养时间的延长，细胞活力逐渐下降，细胞膜完整性遭到破坏，但同时，非特异性免疫酶的活性增强以抵抗寄生水霉的感染。此外，对EPC凋亡基因casp3a和CTSD的检测表明，casp3a基因的相对含量在24小时时显著增加，并达到培养时间内的最大值（P<0.05）。CTSD基因的含量在12小时时显著增加，并达到最大值（P<0.05）。抗氧化免疫基因serpinh1a和gpx1a的结果与凋亡基因的情况相反。serpinh1a和gpx1a基因的含量在12小时时显著下降（P<0.05），但随着培养时间的延长，在24小时和48小时时含量显著增加（P<0.05）。寄生水霉刺激EPC细胞后，差异代谢物主要集中在脂质、具有生物学作用的化合物和植物化学化合物。KEGG通路主要集中在ABC转运蛋白、甘油磷脂代谢、半胱氨酸和甲硫氨酸代谢、甘氨酸、丝氨酸和苏氨酸代谢、嘌呤代谢。总体而言，寄生水霉可影响细胞活性，破坏EPC细胞的细胞膜，并导致细胞凋亡。然而，EPC细胞也可通过调节自身的非特异性免疫和自身代谢产物来抵抗寄生水霉的入侵，从而保护鱼体免受寄生水霉的感染。
