Establishment and cryopreservation of a cell line derived from caudal fin of endangered catfish Clarias dussumieri Valenciennes, 1840

A New Cell Line from the Brain of Red Hybrid Tilapia (Oreochromis spp.) for Tilapia Lake Virus Propagation

Tilapia lake virus (TiLV) presents a substantial threat to global tilapia production. Despite the development of numerous cell lines for TiLV isolation and propagation, none have been specifically derived from red hybrid tilapia (Oreochromis spp.). In this study, we successfully established a new cell line, RHTiB, from the red hybrid tilapia brain. RHTiB cells were cultured for 1.5 years through over 50 passages and demonstrated optimal growth at 25 °C in Leibovitz-15 medium supplemented with 10% fetal bovine serum at pH 7.4. Morphologically, RHTiB cells displayed a fibroblast-like appearance, and cytochrome oxidase I gene sequencing confirmed their origin from Oreochromis spp. Mycoplasma contamination testing yielded negative results. The revival rate of the cells post-cryopreservation was observed to be between 75 and 80% after 30 days. Chromosomal analysis at the 25th passage revealed a diploid count of 22 pairs (2n = 44). While no visible cytopathic effects were observed, both immunofluorescence microscopy and RT-qPCR analysis demonstrated successful TiLV propagation in the RHTiB cell line, with a maximum TiLV concentration of 107.82 ± 0.22 viral copies/400 ng cDNA after 9 days of incubation. The establishment of this species-specific cell line represents a valuable advancement in the diagnostic and isolation tools for viral diseases potentially impacting red hybrid tilapia.

Establishment of a cobia (Rachycentron canadum) gill cell line: A valuable tool for immune response studies

Cobia (Rachycentron canadum), a commercially important marine fish, has been used to develop a novel gill cell line, designated CG, for the first time. The CG cell line was cultured in Leibovitz's-15 medium with 5% fetal bovine serum (FBS) and successfully sub-cultured more than 110 passages. It underwent verification through sequencing of the mitochondrial cytochrome C oxidase subunit I (COI) gene. Optimal growth rate was achieved when the CG cell line was cultured in a medium supplemented with 5% FBS, 1% Penicillin-Streptomycin (P/S), and 5 parts per thousand (ppt) of coral sea salt water, maintained at a temperature of 27 °C. The addition of 5 ppt of salt in the growth medium suggests that this cell line could be a viable in vitro tool for marine ecosystem toxicological studies or for culturing marine parasitic microorganisms. The CG cell line was also successfully transfected using the pTurbo-GFP plasmids, showing an 18% efficiency, with observable GFP expression. Furthermore, the cell line has been effectively cryopreserved. Gene expression analysis indicated that the CG cell line exhibits responsive regulation of immune gene expression when exposured to various stimulants, highlighting its potential as an in vitro platform for immune response studies. This makes it suitable for exploring dynamic immune signaling pathways and host-pathogen interactions, thereby offering valuable insights for therapeutic development.

Fish cell line: depositories, web resources and future applications

Cell lines are important bioresources to study the key biological processes in the areas like virology, pathology, immunology, toxicology, biotechnology, endocrinology and developmental biology. Cell lines developed from fish organs are utilized as a model in vitro system in disease surveillance programs, pharmacology, drug screening and resolving cases of metabolic abnormalities. During last decade, there were consistent efforts made globally to develop new fish cell lines from different organs like brain, eye muscles, fin, gill, heart, kidney, liver, skin, spleen, swim bladder, testes, vertebra etc. This increased use and development of cell lines necessitated the establishment of cell line depositories to store/preserve them and assure their availability to the researchers. These depositories are a source of authenticated and characterized cell lines with set protocols for material transfer agreements, maintenance and shipping as well as logistics enabling cellular research. Hence, it is important to cryopreserve and maintain cell lines in depositories and make them available to the research community. The present article reviews the current status of the fish cell lines available in different depositories across the world, along with the prominent role of cell lines in conservation of life on land or below water.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-023-00601-2.

Establishment and characterization of the ovary cell line derived from two-spot puffer Takifugu bimaculatus and its application for gene editing and marine toxicology

Takifugu bimaculatus is a marine fish with high nutritional value. Its ovary contains tetrodotoxin (TTX) which is a severe neurotoxin that limits its edible value of it. To understand the mechanism of oogenesis and production of TTX in T. bimaculatus, an ovarian cell line named TBO from an adolescent ovary was established. TBO was composed of fibroblast-like cells that expressed the ovarian follicle cells marker gene Foxl2 and highly expressed TTX binding protein 2 (PSTBP2) but did not express the germ cells marker gene Vasa. Therefore, TBO seems to be mainly composed of follicle cells and possibly a small percentage of oocytes. Electroporation was used to successfully transfect the pEGFP-N1 and pNanog-N1 vectors into the TBO cell line with a high transfection efficiency. The morphological changes and survival rates of the exposed cells proved that this cell line was effective for exposure to conotoxins (CTXs), another group of toxins related to food safety. Furthermore, PSTBP2 was knocked out in TBO using CRISPR/Cas9 technology, showing that sgRNA2 could mutate PSTBP2. The results suggested that TBO will be more convenient, efficient, and rapid for reproduction and toxicology investigation, and gene editing. This study laid the groundwork for future research into the fish gonadal cell culture and food-related marine toxins. In conclusion, a cell line has been generated from T. bimaculatus, which might represent a valuable model for fish studies in the fields of toxicology and gene editing.

Cell line derived from muscle of Gymnocypris przewalskii, a species of Schizothoracinae in Qinghai Lake, Qinghai-Tibet Plateau

Gymnocypris przewalskii (naked carp), a native teleost, plays an important role in the ecosystem of Qinghai Lake (altitude, 3.2 km) on the Qinghai-Tibet Plateau in China. We developed a new cell line from the muscle of G. przewalskii using the explant technique and named the cell line GPM. This cell line was maintained in DMEM medium (high glucose) supplemented with 15% fetal bovine serum (FBS). The cell line was successfully subcultured up to 32 passages and was authenticated by immunofluorescence assay, sequencing the mitochondrial cytochrome C oxidase subunit I (COI) and 16S rRNA genes, and by chromosome analysis. In the medium containing 15% FBS, the cell line could be passaged stably at 25 °C. The GPM cell line could express green fluorescent protein (GFP) with a CMV promoter with about 5% transfection efficiency. MTT tests showed that Clostridium botulinum toxin (BTX) was toxic to the cell line. The cell line could be successfully cryopreserved in liquid nitrogen with a revival efficiency of over 70%. This study demonstrated that the GPM cell line can be used as an important tool for understanding the physiological characteristics of G. przewalskii, and it can provide a resource for studying gene function and toxicological reactions in vitro.

The molecular regulation mechanism of dmrt1-based on the establishment of the testis cell line derived from two-spot puffer Takifugu bimaculatus

The establishment of fish cell lines can provide an important in vitro model for developmental biology, pathology, and genetics and also an effective tool to investigate the interactions and related functions of genes. Two-spot puffer Takifugu bimaculatus is a high economic and nutritional value marine fish in Fujian in recent years. Nevertheless, dmrt1 plays a key role in the male differentiation from invertebrates to vertebrates. To understand the molecular regulatory mechanisms of dmrt1 in T. bimaculatus, a testis cell line called TBTc from a juvenile testis of this organism was established with modified Leibovitz's L-15 medium supplemented with 20% FBS, fish serum, embryo extract, and other growth factors. The TBTc with a stable karyotype can be passaged continuously, which was composed of fibroblast-like cells and expressed the marker genes of male-special cells, dmrt1, and amh, and the absence of vasa expression may rule out the possibility of the presence of germ cells. Therefore, TBTc appeared to consist of the mixture of the Sertoli cell and germ cell of the testis. The dmrt1 was significantly expressed in the testes and slightly expressed in the late embryonic development, illustrating that the dmrt1 may participate in the molecular regulation of gonads development and sex differentiation. With the high transfection efficiency of TBTc by electroporation, the cell lines could be used effectively in the study for the expression of exogenous and endogenous genes. Meanwhile, after the knockdown of dmrt1, the morphological changes and survival rates of cells proved that dmrt1 could affect the growth of testicular cells. Furthermore, with the loss of dmrt1, the expression of male-bias genes amh, sox9, and cyp11a was significantly decreased, and the expression of female-bias genes foxl2, sox3, and cyp19a was increased, which suggested that dmrt1 upregulates amh, sox9, and cyp11a and downregulates foxl2, sox3, and cyp19a to participate in the testis development. As a first fish gonadal cell lines of T. bimaculatus, which can be a more convenient, efficient, and rapid model for the investigation of the expression and function of genes, the results will lay a foundation for the next study of the molecular regulation mechanism in gonadal development and sex determination of fish in the future.

Establishment of a cell line derived from the gills of Gymnocypris przewalskii, an endemic Schizothoracine fish from Qinghai Lake of Tibet Plateau

Gymnocypris przewalskii (Naked carp), a native teleost, plays an important role in maintaining the ecological balance of Lake Qinghai (altitude, 3.2 km), the largest saline lake in China. In this study, a new gill cell line from G. przewalskii was developed using the explant technique and named as GPG. This cell line was maintained in Dulbecco's Modified Eagle Medium (DMEM) (high glucose), supplemented with 15% fetal bovine serum (FBS), and was successfully subcultured up to 32 passages. Meanwhile, this cell line was also authenticated by sequencing the mitochondrial cytochrome C oxidase subunit I (COI) and 16S rRNA genes and by chromosome analysis. With the Cytomegalovirus (CMV) promoter, the GPG cell line could express green fluorescent protein (GFP) at about 5% transfection efficiency. MTT test showed that Clostridium botulinum toxin (BTX) was toxic to the cell line. After cryopreservation with 10% dimethyl sulfoxide (DMSO), this cell line could be successfully revived at an efficiency over 70%. This study revealed that the GPG cell line could be used as materials for physio-chemical investigation of G. przewalskii and also provided a tool for gene function study and toxicological reaction in vitro.