Establishment and Characterisation of Skin Cell Line of Schizothorax prenanti and Its Application Into Pathogen Infection

Schizothorax prenanti is an important economic Cyprinidae fish endemic to the upper reaches of the Yangtze River in China. The wild population of S. prenanti continues to decline and has been listed as an endangered fish because of environmental pollution and overfishing. Herein, the skin cell line (SPSK) of S. prenanti was established using the tissue block method to aid in protecting S. prenanti at the cellular level and provide a skin cell line that can be applied in functional genomics and disease aetiology of the spring viraemia of carp virus (SVCV), which is highly infectious in Cyprinidae fish. The SPSK cell line was sub-cultured to more than 30 generations at 24°C in L-15 medium supplemented with 15% fetal bovine serum (FBS). Karyotype analysis further revealed that the chromosome number of SPSK ranged between 140 and 149, with 146 accounting for the highest proportion. Significant fluorescent signals were observed after transfection of SPSK with pEGFP-N1 and Cy3-siRNA, with a 30% and 90% transfection efficiency, respectively. Severe cytopathic effects (CPE) were also observed when SPSK was infected with SVCV, and the SVCV glycoprotein gene was detected by RT-PCR, indicating that SPSK was susceptible to SVCV. To further explore the mechanism of bacterial infection, transcriptome analysis was conducted for LPS treated SPSK cells and 9099 differentially expressed genes were identified. These genes significantly enriched into pathways including the Haematopoietic Cell Lineage and Primary immunodeficiency. Furthermore, seven predominantly expressed epidermal maker genes were identified by transcriptomic data, suggesting that SPSK cells were mainly derived from skin epidermis, composed of epidermal stem cell, Merkel cell, and immune cell. The establishment and characterisation of SPSK revealed its application in functional genomics and aetiology studies, making it a favourable tool for exploring disease control in S. prenanti and recovering fish resources.