Establishment and characterization of a telomerase immortalized porcine luteal cells

Androgen receptor gene deficiency results in the reduction of steroidogenic potential in porcine luteal cells

Luteal steroidogenesis is critical to implantation and pregnancy maintenance in mammals. The role of androgen receptors (AR) in the progesterone (P4) producing luteal cells of porcine corpus luteum (CL) remains unexplored. The aim of the present study was to establish AR gene knock out (KO) porcine luteal cell culture system model by CRISPR/Cas9 genome editing technology and to study the downstream effects of AR gene deficiency on steroidogenic potential and viability of luteal cells. For this purpose, genomic cleavage detection assay, microscopy, RT-qPCR, ELISA, annexin, MTT, and viability assay complemented by bioinformatics analysis were employed. There was significant downregulation (p < 0.05) in the relative mRNA expression of steroidogenic marker genes STAR, CYP11A1, HSD3B1 in AR KO luteal cells as compared to the control group, which was further validated by the significant (p < 0.05) decrease in the P4 production. Significant decrease (p < 0.05) in relative viability on third passage were also observed. The relative mRNA expression of hypoxia related gene HIF1A was significantly (p < 0.05) downregulated in AR KO luteal cells. Protein-protein interaction analysis mapped AR to signaling pathways associated with luteal cell functionality. These findings suggests that AR gene functionality is critical to luteal cell steroidogenesis in porcine.

Construction and Characterization of Immortalized Fibroblast Cell Line from Bactrian Camel

Immortalized cell lines with many advantages are widely used in various experimental contexts by many different labs. However, the absence of available cell lines poses difficulties for research in some species, such as camels. To establish an immortalized Bactrian camel fibroblast (iBCF) cell line and understand its biological characteristics, primary fibroblast cells from Bactrian camels were isolated and purified using enzymatic digestion in this study, and telomerase reverse transcriptase (hTERT) vectors were introduced into primary BCF (pBCF) for continuous passage to 80 generations after screening with G418. The cell morphology of different generations was examined under a microscope. Cell cycle and viability were evaluated by flow cytometry and CCK-8 assay, respectively. Cellular genes expression was monitored by qPCR, immunofluorescence, and Western blot, respectively. Chromosomes were determined by karyotyping. The results showed that like most other cells, both pBCF and iBCF were sensitive to nutrient concentrations and adapted to culture in the medium with 4.5 g/L glucose and 10% fetal bovine serum (FBS) concentration. hTERT gene was introduced and stably expressed in iBCF cells, which promoted BCF cell immortalization. The fibroblast specific marker vimentin (VIM) is expressed in both pBCF and iBCF, but epithelial marker cytokeratin18 (CK18) expression is weak in BCF cells. Proliferation and viability detection showed that hTERT-induced iBCF exhibits faster growth rates and higher viability than pBCF. Karyotyping showed that iBCF maintained the same number and morphology of chromosomes as the pBCF. This study demonstrated that we have successfully constructed an immortalized Bactrian camel fibroblast cell line, which was named BCF23. The establishment of the BCF23 cell line provides a foundation for expanding camel-related research.

Expressions of ghrelin and GHSR-1a in the corpus luteum and the stimulatory effect of ghrelin on luteal function of pregnant sows

Studies have shown that ghrelin played direct actions in ovarian function, but the direct role of ghrelin in corpus luteum (CL) of pregnant sows has remained obscure. The study aimed to examine the expressions of ghrelin and its functional receptor (GHSR-1a) in the CL of sows during pregnancy, and evaluate the role of ghrelin in CL function of pregnant sows. Immunohistochemistry analysis showed that ghrelin and GHSR-1a are both predominantly localized in the luteal cells of pregnant sows CL. Strong immunoreactivity for ghrelin and GHSR-1a is detected at days 20 (early) and 50 (middle), but weak immunoreactivity is observed at days 90 (late) post mating. Similarly, there is a significant effect of pregnant phase on the expression (mRNA and protein) of ghrelin and GHSR-1a in the CL, with higher levels at days 20 (early) and 50 (middle), and lower values at 90 (late) post mating. In vitro, treatments of luteal cells with ghrelin (from 0.01 to 10 ng/mL) are promoted cell viability and P4 secretion in a dose-dependent manner. Ghrelin is also accelerated the LH-induced P4 secretion in luteal cells. Moreover, ghrelin is induced the release and mRNA expression of LH, and increased the release of prostaglandin (PG)E₂, but reduced the secretion of PGF_2α in luteal cells. In conclusion, the presences of ghrelin and GHSR-1a in the porcine CL during pregnancy, and the stimulatory effect of ghrelin on luteal cells suggest positive regulation by ghrelin in CL function of pregnant sows.

Luteinizing Hormone Effect on Luteal Cells Is Dependent on the Corpus Luteum Stage in Felids

Simple Summary

The corpus luteum is a transient endocrine gland on the mammalian ovary, and its main function is to produce progesterone. Knowledge about the corpus luteum in felids is very limited and luteolytic and luteotrophic factors which regulate its maintenance and regression are not extensively studied. Information about corpus luteum function is needed to understand breeding strategies and to successfully implement assisted reproductive techniques for felids, of which most of the species are threatened. The aim of this study was to reveal the effect of luteinizing hormone on cultured luteal cells from corpora lutea obtained from selected felids and to investigate the protein expression of steroidogenic enzyme 3β-hydroxysteroid dehydrogenase by immunohistology.

Abstract

The objective of this study was to investigate the effect of luteinizing hormone (LH) on steroidogenic luteal cells obtained from corpora lutea (CL) of the domestic cat and selected wild felids. Luteal cells were isolated enzymatically from CL at different developmental stages and cultured for two days in the presence and absence of 100 ng/mL LH, respectively. Functionality was assessed by progesterone (P4) accumulation in cell culture media determined by ELISA. In addition, steroidogenic function was confirmed using immunohistochemistry for 3β-hydroxysteroid dehydrogenase (HSD3B). The enzymatic method allowed for the isolation of mostly small luteal cells in all investigated felids. Treatment with LH resulted in an increase in P4 secretion of cultured luteal cells obtained from CL in the formation stage (African lion) and development/maintenance stage (domestic cat (p < 0.05), Javan leopard), whereas luteal cells from more advanced stages of luteal development (regression) responded moderately or not at all to LH stimulation (domestic cat, Asiatic golden cat, Asiatic lion). The protein signal for HSD3B on CL was visible until development/maintenance. In conclusion, this study shows that LH promotes P4 production in luteal cells only until the onset of regression, when morphological signs are visible on the CL of felids and HSD3B is no longer detectable.

Telomerase activation in the treatment of aging or degenerative diseases: a systematic review

Telomeres are protective structures that are shortened during the lifetime, resulting in aging and degenerative diseases. Subjects experiencing aging and degenerative disorders present smaller telomeres than young and healthy ones. The size of these structures can be stabilized by telomerase, an enzyme which is inactive in adult tissues but functional in fetal and newborn tissues and adult testes and ovaries. The aim of this study was to perform a systematic review to evaluate the effect of telomerase activation in the treatment of degenerative and aging disorders. We accomplished the search using the Pubmed interface for papers published from September 1985 to April 16th, 2020. We found twenty one studies that matched our eligibility criteria. I concluded that telomerase is probably a potential and safe treatment for aging and degenerative diseases, demonstrating neither side effects nor risk of cancer in the selected studies. Further studies in humans are needed to confirm safety and efficiency of this treatment.

Establishment and Characterization of an Immortalized Porcine Oral Mucosal Epithelial Cell Line as a Cytopathogenic Model for Porcine Circovirus 2 Infection

Porcine circovirus 2 (PCV2) is a major etiological agent for porcine circovirus-associated diseases and causes enormous economic losses in domestic and overseas swine production. However, there are currently no suitable cell models to study the cytopathic effects (CPE) of PCV2 in vitro, which severely restricts the study of PCV2 pathogenesis. In the present study, we established an immortalized porcine oral mucosal epithelial cell line (hTERT-POMEC) by introducing the hTERT gene into primary porcine oral mucosal epithelial cells (POMECs) derived from a neonatal, unsuckled piglet. The hTERT-POMEC cells have a homogeneous cobblestone-like morphology and retain the basic physiological properties of primary POMECs. No chromosome abnormality and tumorigenicity transformation was observed in immortalized hTERT-POMECs. Viral infection assays demonstrated that PCV2 propagated and caused CPE in hTERT-POMECs. We conclude that the immortalized cell line hTERT-POMEC is a crucial tool for further research into the pathogenesis of PCV2.

Establishment and characterization of a telomerase-immortalized porcine bronchial epithelial cell line

Primary porcine bronchial epithelial cells (PBECs) are an ideal model to study the molecular and pathogenic mechanisms of various porcine respiratory pathogens. However, the short lifespan of primary PBECs greatly limit their application. Here, we isolated and cultured primary PBECs and established immortalized PBECs by transfecting primary PBECs with the pEGFP-hTERT recombinant plasmid containing human telomerase reverse transcriptase (hTERT). Immortalized PBECs (hTERT-PBECs) retained the morphological and functional features of primary PBECs as indicated by cytokeratin 18 expression, telomerase activity assay, proliferation assays, karyotype analysis, and quantitative reverse-transcriptase polymerase chain reaction. Compared to primary PBECs, hTERT-PBECs had higher telomerase activity, extended replicative lifespan, and displayed enhanced proliferative activity. Moreover, this cell line is not transformed in vitro and does not exhibit a malignant phenotype in vivo, suggesting that it can be safely used in further studies. Besides, hTERT-PBECs were susceptible to swine influenza virus of H3N2 subtype and porcine circovirus type 2. In conclusion, the immortalized hTERT-PBECs represent a valuable in vitro model, which can be widely used in the study of porcine respiratory pathogenic infections.