Establishment of a dorsal fin cell line from largemouth bass (Micropterus salmoides) and its apoptosis induced by MSRV

The largemouth bass (Micropterus salmoides), also known as the California bass, is an important freshwater aquaculture species worldwide. Micropterus salmoides rhabdovirus (MSRV) is a major pathogen threatening the sustainable development of largemouth bass aquaculture. Here, we established a novel cell line, named Micropterus salmoides dorsal fin (MSDF) cell line, which supports MSRV propagation and enables investigation of virus-induced apoptosis. Transcriptome analysis showed that MSRV infection altered host gene expression, upregulating 313 genes and downregulating 126 genes, which were functionally enriched in immune/metabolic pathways, including the p53 signaling pathway, apoptosis, peroxisome, lysosome pathways, and nucleotide metabolism. Furthermore, DAPI and TUNEL staining confirmed that MSRV infection induced apoptosis in MSDF cells. Notably, inhibiting cell apoptosis suppressed viral replication, and mitochondrial dysfunction was implicated in MSRV-triggered apoptosis. Collectively, we developed an MSRV-susceptible cell line (MSDF), which serves as an ideal platform for characterizing MSRV pathogenesis, particularly its apoptotic mechanisms.