Combinatorial expression of cell cycle regulators is more suitable for immortalization than oncogenic methods in dermal papilla cells

Establishment of an immortalized sheep mammary epithelial cell line for studying milk fat and protein synthesis

The mammary gland, crucial for milk production in mammals, presents challenges for in vitro study due to its complex structure and limited cell lifespan. We addressed this by introducing the SV40 large T antigen into primary mammary epithelial cells (MECs) from sheep, creating an immortalized T-tag MEC line. This line, stable for over 50 passages, maintained typical epithelial cell morphology during long-term culture. Through transcriptome sequencing and validation, we discovered 3833 differentially expressed genes between MECs and T-tag MEC line, encompassing key biological processes and signaling pathways like cell cycle, p53, and cancer. The cell line, expressing MEC markers (KRT8, KRT18, proliferating cell nuclear antigen, SV40, CSN2, and acetyl-CoA carboxylase alpha), proved capable of synthesizing milk fat and protein. Despite its infinite proliferation potential, the T-tag MEC line showed no tumor formation in mice or cell migration in vitro, indicating stability. This development offers a valuable resource for studying MECs in dairy sheep, facilitating the advancement of long-term culture systems and in vitro lactation bioreactors.

Transcriptome-wide profiling for melanocytes derived from newborn and adult human epidermis with enhanced proliferation

The senescence-associated protein p16INK4A acts as a limiter element in cell-cycle progression. The loss of p16INK4A function is causally related to cellular immortalization. The increase in p16INK4A levels with advancing age was demonstrated in melanocytes. However, the characteristic difference between young and senescent melanocytes affecting immortalization of melanocytes remains unclear. In this study, we generated 10 different cell lines in total from newborn (NB) and adult (AD) primary normal human epidermal melanocytes (NHEM) using four different methods, transduction of CDK4R24C and cyclin D1 (K4D), K4D with TERT (K4DT), SV40 T-antigen (SV40T), and HPV16 E6 and E7 (E6/E7) and performed whole transcriptome sequencing analysis (RNA-Seq) to elucidate the differences of genome-wide expression profiles among cell lines. The analysis data revealed distinct differences in expression pattern between cell lines from NB and AD although no distinct biological differences were detected in analyses such as comparison of cell morphology, evaluation of cell proliferation, and cell cycle profiles. This study may provide useful in vitro models to benefit the understanding of skin-related diseases.

Controlled cell proliferation and immortalization of human dental pulp stem cells with a doxycycline-inducible expression system

Human dental pulp stem cells are a potentially useful resource for cell-based therapies and tissue repair in dental and medical applications. However, the primary culture of isolated dental pulp stem cells has notably been limited. A major requirement of an ideal human dental pulp stem cell culture system is the preservation of efficient proliferation and innate stemness over prolonged passaging, while also ensuring ease of handling through standard, user-friendly culture methods. In this study, we have engineered a novel human dental pulp stem cell line, distinguished by the constitutive expression of telomerase reverse transcriptase (TERT), and the conditional expression of the R24C mutant cyclin-dependent kinase 4 (CDK4R24C) and Cyclin D1. We have named this cell line Tet-off K4DT hDPSCs. Furthermore, we have conducted a comprehensive comparative analysis of their biological attributes in relation to a previously immortalized human dental pulp stem cells, hDPSC-K4DT, which were immortalized by the constitutive expression of CDK4R24C, Cyclin D1 and TERT. In Tet-off K4DT cells, the expression of the K4D genes can be precisely suppressed by the inclusion of doxycycline. Remarkably, Tet-off K4DT cells demonstrated an extended cellular lifespan, increased proliferative capacity, and enhanced osteogenic differentiation potential when compared to K4DT cells. Moreover, Tet-off K4DT cells had no observable genomic aberrations and also displayed a sustained expression of stem cell markers even at relatively advanced passages. Taken together, the establishment of this new cell line holds immense promise as powerful experimental tool for both fundamental and applied research involving dental pulp stem cells.

Establishment and comparison of human term placenta-derived trophoblast cells†

Research on the biology of fetal-maternal barriers has been limited by access to physiologically relevant cells, including trophoblast cells. In this study, we describe the development of a human term placenta-derived cytotrophoblast immortalized cell line (hPTCCTB) derived from the basal plate. Human-term placenta-derived cytotrophoblast immortalized cell line cells are comparable to their primary cells of origin in terms of morphology, marker expression, and functional responses. We demonstrate that these can transform into syncytiotrophoblast and extravillous trophoblasts. We also compared the hPTCCTB cells to immortalized chorionic trophoblasts (hFM-CTC), trophoblasts of the chorionic plate, and BeWo cells, choriocarcinoma cell lines of conventional use. Human-term placenta-derived cytotrophoblast immortalized cell line and hFM-CTCs displayed more similarity to each other than to BeWos, but these differ in syncytialization ability. Overall, this study (1) demonstrates that the immortalized hPTCCTB generated are cells of higher physiological relevance and (2) provides a look into the distinction between the spatially distinct placental and fetal barrier trophoblasts cells, hPTCCTB and hFM-CTC, respectively.

Establishment and Characterization of Immortalized Human Dermal Papilla Cells Expressing Human Papillomavirus 16 E6/E7

Primary human dermal papilla cells (HDPCs) are often preferred in studies on hair growth and regeneration. However, primary HDPCs are limited by their reduced proliferative capacity, decreased hair induction potential, and extended doubling times at higher passages. To overcome these limitations, pTARGET vectors containing human papillomavirus16 (HPV16) E6/E7 oncogenes were transfected into HDPCs and selected using G-148 to generate immortalized cells here. HPV16 E6/E7 oncogenes were efficiently transfected into primary HDPCs. Immortalized HDPC showed higher proliferative activity than primary HDPC, confirming an increased proliferation rate. Expression of p53 and pRb proteins was downregulated by E6 and E7, respectively. E6/E7 expressing HDPC cells revealed that cyclin-dependent kinase (CDK) inhibitor p21 expression was decreased, while cell cycle-related genes and proteins (CDK2 and cyclin E) and E2F family genes were upregulated. Immortalized HDPCs maintained their responsiveness to Wnt/β-catenin pathway and hair follicle formation capability, as indicated by their aggregative properties and stemness. E6/E7 immortalized HDPCs may facilitate in vitro hair growth and regeneration studies.

Characterization of Common Minke Whale (Balaenoptera Acutorostrata) Cell Lines Immortalized with the Expression of Cell Cycle Regulators

Primary cultured cells cannot proliferate infinite. The overcoming of this limit can be classified as immortalization. Bypass of p16 senescence protein induces efficient immortalization various types of mammalians is previously reported. However, the Cetacea species is not known. Here, that common minke whale-derived cells can be immortalized with a combination of human genes, mutant cyclin-dependent kinase 4 (CDK4R24C ), cyclin D1, and Telomerase Reverse Transcriptase (TERT) is reported. These results indicate that the function of cell cycle regulators in premature senescence is evolutionarily conserved. This study describes the conserved roles of cell cycle regulators in the immortalization of cells from humans to Cetacea species. Furthermore, using RNA-seq based on next-generation sequencing, the gene expression profiles of immortalized cells are compared with parental cells as well as those immortalized with SV40 large T antigen, which is once a popular method for cellular immortalization. The profiling results show that newly established common minke-whale-derived immortaliozed cells have completely different profiles from SV40 cells. This result indicates that the expression of mutant CDK4, cyclin D1, and TERT enables to establish immortalized cell lines with different biological nature from SV40 expressing cells.

Immortalization of American miniature horse-derived fibroblast by cell cycle regulator with normal karyotype

Immortalized cells serve as a crucial research tool that capitalizes on their robust proliferative properties for functional investigations of an organism. Establishing an immortalized American miniature horse cell line could yield valuable insights into these animals' genetic and physiological characteristics and susceptibility to health issues. To date, immortalized small horse cells with normal karyotypes have not been established. In this study, we successfully established primary and immortalized fibroblast cell lines through the combined expression of human-derived mutant cyclin-dependent kinase 4 (CDK4R24C), cyclin D1, and Telomerase Reverse Transcriptase (TERT), although CDK4R24C and cyclin D1, SV40T and TERT did not result in successful immortalization. Our comparison of the properties of these immortalized cells demonstrated that K4DT immortalized cells maintain a normal karyotype. Ultimately, our findings could pave the way for the development of targeted interventions to enhance the health and well-being of American miniature horses.

Comprehensive transcriptome data to identify downstream genes of testosterone signalling in dermal papilla cells

Testosterone-related steroid hormones are associated with various types of diseases, including prostate cancer and androgenetic alopecia (AGA). The testosterone or dihydroxy testosterone (DHT) circulates through the blood, binds to the androgen receptor (AR) in the cytoplasm, and finally enters the nucleus to activate downstream target genes. We previously found that immortalized dermal papilla cells (DPCs) lost AR expression, which may be explained by the repeated cell passages of DPCs. To compensate for the AR expression, DPCs that express AR exogenously were established. In this study, we performed an RNA-Seq analysis of the AR-expressing and non-AR-expressing DPCs in the presence or absence of DHT to identify the downstream target genes regulated by AR signalling. Furthermore, we treated DPCs with minoxidil sulphate, which has the potential to treat AGA. This is the first comprehensive analysis to identify the downstream genes involved in testosterone signalling in DPCs. Our manuscript provides high-priority data for the discovery of molecular targets for prostate cancer and AGA.

Novel cell lines derived from Chinese hamster kidney tissue

Immortalized kidney cell lines are widely used in basic and applied research such as cell permeability tests and drug screening. Although many cell lines have been established from kidney tissues, the immortalization process has not been clarified in these cell lines. In this study, we analyzed the phenotypic changes that occurred during the immortalization of kidney cells derived from Chinese hamster tissue in terms of karyotype and gene expression profiles. In the newly established cell line, designated as CHK-Q, gene expression profiles at each stage of the immortalization process and during the adaptation to serum-free conditions were analyzed by DNA microarray. Renal stem cell markers CD24 and CD133 were expressed in CHK-Q cells, suggesting that CHK-Q cells were transformed from renal stem cells. Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis to identify the pathways of upregulated and downregulated genes revealed that the immortalization of CHK-Q cells was associated with increased fluctuations in the expression of specific proto-oncogenes. Karyotype analysis of spontaneously immortalized CHK-Q cells indicated that CHK-Q chromosomes had a typical modal number of 23 but possessed slight chromosomal abnormalities. In this study, we investigated the mechanism of cell environmental adaptation by analyzing gene expression behavior during the immortalization process and serum-free adaptation. CHK-Q cells are applicable to the fields of biotechnology and biomedical science by utilizing their characteristics as kidney-derived cells.

Generation and characterization of human Fetal membrane and Decidual cell lines for reproductive biology experiments†

Human fetal membrane and maternal decidua parietalis form one of the major feto-maternal interfaces during pregnancy. Studies on this feto-maternal interface is limited as several investigators have limited access to the placenta, and experience difficulties to isolate and maintain primary cells. Many cell lines that are currently available do not have the characteristics or properties of their primary cells of origin. Therefore, we created, characterized the immortalized cells from primary isolates from fetal membrane-derived amnion epithelial cells, amnion and chorion mesenchymal cells, chorion trophoblast cells and maternal decidua parietalis cells. Primary cells were isolated from a healthy full-term, not in labor placenta. Primary cells were immortalized using either a HPV16E6E7 retroviral or a SV40T lentiviral system. The immortalized cells were characterized for the morphology, cell type-specific markers, and cell signalling pathway activation. Genomic stability of these cells was tested using RNA seq, karyotyping, and short tandem repeats DNA analysis. Immortalized cells show their characteristic morphology, and express respective epithelial, mesenchymal and decidual markers similar to that of primary cells. Gene expression of immortalized and primary cells were highly correlated (R = 0.798 to R = 0.974). Short tandem repeats DNA analysis showed in the late passage number (>P30) of cell lines matched 84-100% to the early passage number (<P10) of the cell lines revealing there were no genetic drift over the passages. Karyotyping also revealed no chromosomal anomalies. Creation of these cell lines can standardize experimental approaches, eliminate subject to subject variabilities, and benefit the reproductive biological studies on pregnancies by using these cells.

Detailed chromosome analysis of wild-type, immortalized fibroblasts with SV40T, E6E7, combinational introduction of cyclin dependent kinase 4, cyclin D1, telomerase reverse transcriptase

Cell immortalization enables us to expand the cultured cell infinitely. However, the process of immortalization sometimes changes the nature of the original cell. In this study, we established immortalized embryonic fibroblasts with oncogenic SV40T and human papilla virus-derived E6E7, combinational expression of mutant cyclin-dependent kinase 4 (CDK4), cyclin D1, and telomerase reverse transcriptase (TERT) from identical primary wild-type human embryonic fibroblasts (HE16). After the establishment of immortalized cells, we compared the details of chromosome condition with the G-banding and Q-banding methods. There is no example of detailed analysis so far about chromosome abnormalities, such as trisomy, ring chromosome, reciprocal translocation, and dicentric chromosomes. The detailed chromosome analysis revealed that immortalized cells with SV40T and E6E7 showed intensive chromosome abnormalities, such as gain or loss of the chromosomes all through the genome. Furthermore, we detected that the incidence of chromosome abnormities in the immortalized cell with the combinational introduction of R24C mutant of CDK4, cyclin D1, and TERT is almost identical to that of wild-type cell. Furthermore, short tandem repeat analysis demonstrated that the origin of K4DT cell is primary HE16. These results showed that cellular immortalization with CDK4, cyclin D1, and TERT is more advantageous in keeping the chromosome's original condition than oncogenic immortalization methods.

Establishment of Three Types of Immortalized Human Skin Stem Cell Lines Derived from the Single Donor

Currently, human-skin derived cell culture is a basic technique essential for dermatological research, cellular engineering research, drug development, and cosmetic development. But the number of donors is limited, and primary cell function reduces through cell passage. In particular, since adult stem cells are present in a small amount in living tissues, it has been difficult to obtain a large amount of stem cells and to stably culture them. In this study, skin derived cells were isolated from the epidermis, dermis, and adipose tissue collected from single donor, and immortalization was induced through gene transfer. Subsequently, cell lines that could be used as stem cell models were selected using the differentiation potential and the expression of stem cell markers as indices, and it was confirmed that these could be stably cultured. The immortalized cell lines established in this study have the potential to be applied not only to basic dermatological research but also to a wide range of fields such as drug screening and cell engineering.