Establishment of a Coilia nasus Gonadal Somatic Cell Line Capable of Sperm Induction In Vitro

SIMPLE SUMMARY: The induced differentiation of sperm cells in vitro is a key technology for germplasm conservation. Coilia nasus is one of the “Three Delicious Species in the Yangtze River”, its germplasm resources have declined significantly over the past few decades. To protect the declining of Coilia nasus, a gonadal somatic cell line from fresh gonadal tissues (CnGSC) of adult Coilia nasus was isolated that can be cultured and proliferated in vitro for a long time. Co-culture of CnGSC with a medaka spermatogonial stem cell (SG3) line led to the induction of sperm in vitro. Further experiments showed that it is the lysate of CnGSC that induced the differentiation of SG3 in vitro. Our findings will help to further study the conservation of germplasm resources of endangered fishes with important values. ABSTRACT: Coilia nasus is an important economic anadromous migratory fish of the Yangtze River in China. In recent years, overfishing and the deterioration of the ecological environment almost led to the extinction of the wild resources of C.nasus. Thus, there is an urgent need to protect this endangered fish. Recently, cell lines derived from fish have proven a promising tool for studying important aspects of aquaculture. In this study, a stable C. nasus gonadal somatic cell line (CnCSC) was established and characterized. After over one year of cell culture (>80 passages), this cell line kept stable growth. RT-PCR results revealed that the CnGSC expressed some somatic cell markers such as clu, fshr, hsd3β, and sox9b instead of germ cell markers like dazl, piwi, and vasa. The strong phagocytic activity of CnGSC suggested that it contained a large number of Sertoli cells. Interestingly, CnGSC could induce medaka spermatogonial cells (SG3) to differentiate into elongated spermatids while co-cultured together. In conclusion, we established a C. nasus gonadal somatic cell line capable of sperm induction in vitro. This research provides scientific evidence for the long-term culture of a gonadal cell line from farmed fish, which would lay the foundation for exploring the regulatory mechanisms between germ cells and somatic cells in fish.