Development and characterization of cell culture systems from Puntius (Tor) chelynoides (McClelland)

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.

Development and characterization of a new muscle cell culture system from Clarias magur (Hamilton, 1822)

The cell line has been used as a novel in vitro tool for executing several studies in life sciences. The current study aimed to develop and characterize a muscle cell culture system derived from Clarias magur. The primary muscle cell cultures derived from the caudal peduncle muscle have been successfully sub cultured up to 13 passages to establish a new muscle cell culture system known as CMM. At a temperature of 28 °C, L-15 medium supplemented with 20% FBS produced the maximum growth of muscle cells. However, muscle cells were optimized to grow at 10% FBS. To enhance the proliferation capacity of the CMM cells, a growth-promoting factor bFGF (10 ng/ml) was added, thereby reducing the time interval of passages for the subsequent cultures. DNA barcoding of the CMM cell culture system authenticated the species of origin. The cell culture system was successfully cryopreserved by a slow freezing procedure at - 80 °C with a revival efficiency of 60%.

Development of a cell line from skeletal trunk muscle of the fish Labeo rohita

Labeo rohita is a widely cultivated tropical freshwater carp and found in rivers of South Asian region. A new cell line, designated LRM, has been developed from the muscle tissue of L. rohita. Muscle cells were subcultured up to 38 passages in a Leibovitz's-15 (L-15) supplemented with 10% FBS (Fetal Bovine Serum) and 10 ng/ml bFGF. The LRM cells exhibited fibroblastic morphology with a doubling time of 28 h, and a plating efficiency of 17%. A maximum growth rate was observed for LRM cells at 28 °C, 10% FBS and 10 ng/ml bFGF. A cytochrome C oxidase subunit I (COI) gene sequence was used to authenticate the developed cell line. Chromosome analysis revealed 50 diploid chromosomes. The fibroblastic characteristics of the of the LRM cells was confirmed by immunocytochemistry. The expression of MyoD gene in LRM cells was analyzed by quantitative PCR in comparison with passages 3, 18 and 32. The expression of MyoD was higher at passage 18 compared to the passages 3 and 32. The LRM cells attached properly onto the 2D scaffold and the expression of the F-actin filament protein was confirmed by phalloidin staining followed by counter staining with DAPI to observe the distribution of the muscle cell nuclei and the cytoskeleton protein. A revival rate of 70-80% was achieved when the LRM cells were cryopreserved at - 196 °C using liquid nitrogen. This study would further contribute to understanding the in vitro myogenesis and progress toward cultivated fish meat production.

Characterization of a new cell line from ornamental fish Amphiprion ocellaris (Cuvier, 1830) and its susceptibility to nervous necrosis virus

Amphiprion ocellaris (ocellaris clownfish) is one of the most commercially important marine ornamental fish. A cell line designated as OCF was developed for the first time from the caudal fin of this fish species. The cell line was maintained in Leibovitz’s—15 medium supplemented with 15% FBS (Fetal Bovine Serum) and was successfully subcultured up to 34 passages. The cell line was authenticated by sequencing mitochondrial cytochrome C oxidase subunit I (COI) and 16S rRNA genes. The growth rate of the OCF cell line was maximum in medium containing 20% FBS and 1% of 0.2 M NaCl at 28 °C. Chromosome analysis revealed 48 diploid chromosomes. The OCF cell line was transfected with the pMaxGFP plasmid vector with 7% efficiency and GFP expression was observed. The OCF cell line was used for testing nervous necrosis virus (NNV) susceptibility. Cytopathic effect (CPE) was observed in terms of plaque formation after virus inoculation. Nested PCR confirmed the susceptibility of the OCF cell line to NNV. The cell line was successfully cryopreserved by a slow freezing procedure at − 80 °C with a revival efficiency of 70–75%. The study revealed that the OCF cell line would be useful for virological studies. In addition, the cell line would play an important role as an in vitro tool for carrying out toxicological and biotechnological studies.

Development and characterization of a new DRCF cell line from Indian wild strain zebrafish Danio rerio (Hamilton 1822)

Danio rerio, zebrafish, has been widely used as a non-mammalian vertebrate model organism in various studies. The present research describes to develop and characterize a new cell line from a wild strain Indian zebrafish native to Brahmaputra River, Assam, India. The new cell line designated as DRCF was developed from the caudal fin of D. rerio. The cell line was successfully subcultured up to 31 passages. Growth studies revealed that cell growth of DRCF was optimal at 28 °C in L-15 medium supplemented with 20% FBS. Molecular characterization of the DRCF cell line using mitochondrial genes namely cytochrome oxidase subunit I gene (COI) and 16S rRNA authenticated the true origin of the cell line. The chromosome analysis of the DRCF cell line expressed its 50 diploid chromosome number of D. rerio. The immunocytochemical characterization of the cell line exhibited its fibroblastic morphology. The expression of the green fluorescent protein (GFP) following transfection revealed the suitability of the cell line for transfection studies.

Two skin cell lines from wild-type and albino Japanese flounder (Paralichthys olivaceus): establishment, characterization, virus susceptibility, efficient transfection, and application to albinism study

In order to provide an applicable cell platform to study fish pathology and skin pigmentation, two cell lines derived from skin tissues of wild-type and albino Japanese flounder were established and named JFSK_wt and JFSK_alb, respectively. These two cell lines were cultured for 45 passages within approximately 300 days. JFSK_wt and JFSK_alb cells were maintained in Dulbecco's Modified Eagle's Medium and Ham's F-12 Nutrient Mixture (DMEM/F12) supplemented with antibiotics, fetal bovine serum (FBS), 2-mercaptoethanol (2-Me), N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES), and basic fibroblast growth factor (bFGF). The optimal growth temperature for JFSK_wt and JFSK_alb cells was 24 °C, and microscopically, the two cell lines were composed of fibroblast-like cells. Chromosomal analysis revealed that JFSK_wt and JFSK_alb cells had an identical diploid karyotype with 2n = 48t. Results of viral inoculation assays revealed that both cell lines shared similar patterns of viral susceptibility to nervous necrosis virus (NNV). High transfection efficiency was observed in JFSK_wt and JFSK_alb cells transfected with a pEGFP-N3 reporter plasmid and Cy3-siRNA. The detection of dermal marker Dermo-1 showed that these two cells were both derived from the dermis. Finally, three genes involved in the melanogenesis pathway, including adenylate cyclase type 5 (adcy5), microphthalmia-associated transcription factor (mitf), and endothelin B receptor (ednrb), were downregulated in JFSK_alb versus JFSK_wt cells. Thus, the two cell lines, sampled from skin tissue of wild-type and albino Japanese flounder will be not only helpful for fish pathogen research but also beneficial for albinism-related gene function studies.

Establishment of a hepatocyte line for studying biosynthesis of long-chain polyunsaturated fatty acids from a marine teleost, the white-spotted spinefoot Siganus canaliculatus

A hepatocyte line was established from the liver of white-spotted spinefoot Siganus canaliculatus to study the biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFA). The cells from the line, designated S. canaliculatus hepatocyte line (SCHL), grew and multiplied well in Dulbecco's modified Eagle's medium (DMEM)-F12 medium supplemented with 20 mM 4-(2-hydroxyethyl) piperazine-1-ethanesulphonic acid (HEPES), 10% foetal bovine serum (FBS) and 0·5% rainbow trout Oncorhychus mykiss serum at 28° C, showing an epithelial-like morphology and the normal chromosome number of 48 (2n) and have been subcultured for over 60 passages. The identity of the hepatocytes was confirmed by periodic acid Schiff (PAS) staining. The mRNA expression of all genes encoding the key enzymes for LC-PUFA biosynthesis including two desaturases (Δ4 Fad and Δ6-Δ5 Fad) and two elongases (Elovl4 and Elovl5), were detected in all cells from passages 5 to 60 and their expression levels became stable after passage 35 and showed responses to various PUFA incubation. This is similar to the situation determined in the liver of S. canaliculatus that were fed diets containing different fatty acids. These results indicated that SCHL was successfully established and can provide an in vitro tool to investigate lipid metabolism and regulatory mechanisms of LC-PUFA biosynthesis in teleosts, especially marine species.

Establishment and characterization of a piscean PCF cell line for toxicity and gene expression studies as in vitro model

A new piscean fibroblastic cell line termed as PCF derived from the caudal fin tissue of dark mahseer, Puntius (Tor) chelynoides was established and characterized in the present study which was found to be suitable for toxicity and gene expression studies as in vitro model. The cell line grew well in Leibovitz's L-15 medium supplemented with 10% fetal bovine serum (FBS). The cells were able to grow at a temperature ranging from 20 to 28 °C with an optimal growth at 24 °C and the cell line have been expanded in culture for more than 70 passages. Authentication of the cell line was carried out using mitochondrial DNA markers (Cytochrome Oxidase subunit I and 16S ribosomal RNA). Presence of vimentin in the cells confirmed the fibroblastic origin of cell line. Significant cytopathic effects were observed upon exposure of PCF cell line to bacterial extracellular products and the study also validated the suitability of cell line in transgenic applications as well as in genotoxicity assessment as an in vitro model.

Development and characterization of a cell line WAF from freshwater shark Wallago attu

A new epithelial cell line, WAF was developed from caudal fin of freshwater shark, Wallago attu. The cell line was optimally maintained at 28 °C in Leibovitz-15 (L-15) medium supplemented with 20 % fetal bovine serum. The cell line was characterized by various cytogenetic and molecular markers. The cytogenetic analysis revealed a diploid count of 86 chromosomes at different passages. The origin of the cell lines was confirmed by the amplification of 547 and 654 bp sequences of 16S rRNA and cytochrome oxidase subunit I genes of mitochondrial DNA, respectively. WAF cells were characterized for their growth characteristics at different temperature and serum concentration. Epithelial morphology of the cell line was confirmed using immunocytochemistry. Further cell plating efficiency, transfection efficiency and viability of cryopreserved WAF cells was also determined. Cytotoxicity and genotoxicity assessment of cadmium salts on WAF cells by MTT, NR and comet assay illustrated the utility of this cell line as an in vitro model for aquatic toxicological studies. The cell line will be further useful for studying oxidative stress markers against aquatic pollutants.