Extracellular matrix (ECM) pathway involved in skin immune response of Cynoglossus semilaevis upon Vibrio vulnificus infection

Half-smooth tongue sole (Cynoglossus semilaevis) is regarded as a significant commercial marine fish species in China, and frequent outbreaks of vibriosis has led to substantial economic losses. In this study, we investigated the molecular mechanisms underlying the involvement of the extracellular matrix (ECM) signaling pathway in the skin immune response of C. semilaevis infected with Vibrio vulnificus. The results showed that most differentially expressed proteins (DEPs) were identified through iTRAQ proteome analysis, and ten ECM-related proteins were screened at 12 and 36 ​h post-infection (hpi). Notably, several DEPs associated with ECM including HSPG, FN, COCH, LAMB1, LAMC1, TSPN, COL6A1, AMBP, HX and ITGA6 were tested for their expression at the transcriptional level during V. vulnificus infection using qRT-PCR assay. The analysis of protein-protein interaction (PPI) showed that the integrin ITGA6 exhibited obvious interactions among ECM-related DEPs. Furthermore, the spatio-temporal expression of the Csitga6 gene was highest in the skin, gill, muscle, and spleen, but lower in the liver, kidney and intestine. To our knowledge, this is the first report on the involvement of ECM pathway in the skin immune response to V. vulnificus infection, and provides a reference for further study of the ECM mechanism in the mucosal immune response of marine fish.