Development and validation of immortalized bovine mammary epithelial cell line as an in vitro model for the study of mammary gland functions.

This study aimed to develop a bovine mammary epithelial (BME) cell line model, which provides a possibility to determine functional properties of the bovine mammary gland. The primary cell culture was derived from bovine mammary gland tissues and processed enzymatically to obtain cell colonies with epithelial-like morphology. The cultures of BME cells were purified and optimally cultured at 37 °C in DMEM/F12 medium supplemented with 10% fetal bovine serum. The BME cells were identified as epithelial cell line by the evaluating the expression of keratin-18 using immunofluorescence staining. A novel gene expression system strongly enhances the expression of telomerase, has been used to immortalize BME cell line termed hTBME cell line. Interestingly, telomerase remained active even after over 60 passages of hTBME cell line, required for immortalization of BME cells. In addition, the hTBME cell line was continuously subcultured with a spontaneous epithelial-like morphology, with a great proliferation activity, and without evidence of apoptotic and necrotic effects. Further characterization showed that hTBME cell line can be continuously propagated in culture with constant chromosomal features and without tumorigenic properties. Finally, established hTBME cell line was evaluated for mammary gland specific functions. Our results demonstrated that the hTBME cell line was able to retain functional-morphological structure, and functional differentiation by expression of beta (ß)-casein as in the bovine mammary gland in vivo. Taken together, our findings suggest that the established hTBME cell line can serve as a valuable tool for the study of bovine mammary gland functions.

Differential microRNA expression in the serum of patients with nephrotic syndrome and clinical correlation analysis.

Many different microRNAs existed in nephrotic syndrome patients, and they may be involved in nephrotic syndrome occurrence. In order to further clarify miRNAs expression changes in nephrotic syndrome patients and their correlation with clinical features, this study investigated differential microRNA expression in the peripheral serum of patients with nephrotic syndrome and analyzed the correlation between miRNA with largest overexpression level and clinical features. miRNAs microarray was applied to screen different expressed miRNAs in nephrotic syndrome patients. Real-time PCR was performed to verify miRNA expression level. SPSS software was used to analyze correlation between miRNA expression and clinical features. Compared with healthy subjects, 35 miRNAs overexpressed and 24 miRNAs down-regulated in patients. After real-time PCR verification, 6 miRNAs up-regulated in nephrotic syndrome patients, including hsa-miR-181a, hsa-miR-210, hsa-miR-30a, hsa-miR-942, hsa-miR-192 and hsa-miR-586. miRNA-30a significantly overexpressed in nephrotic syndrome patients and with no difference between genders. miRNA-30a expression level in drug resistant nephrotic syndrome patients was obviously higher than the drug sensitive patients. miRNA-30a up-regulated most significantly in mesangial proliferative glomerulonephritis among different pathology types, while it decreased most obviously in glomerular lesions. miRNA differently expressed in the serum of nephrotic syndrome patients. miRNA-30a could be treated as the molecular marker in predict drug resistance and pathological type of nephrotic syndrome.

Differential expression of Axin1, Cdc25c and Cdkn2d mRNA in 2-cell stage mouse blastomeres.

There is increasing evidence to show that 2-cell stage mouse blastomeres have differing developmental properties. Additionally, it has been suggested that such a difference might be due to their distribution of mRNA and/or protein asymmetry. However, to date, the exact genes that are involved in the orientation and order of blastomere division are not known. In this study, some differentially expressed transcripts were identified. Axin1, cell division cycle 25 homolog C (Cdc25c) and cyclin-dependent inhibitor 2D (Cdkn2d) were selected for validation by real-time polymerase chain reaction (PCR) based on published data. Our real-time PCR results demonstrated that Axin1, Cdc25c and Cdkn2d genes had different levels of expression among blastomeres of the mouse 2-cell embryo i.e. the level of Axin1 mRNA was significantly higher in one blastomere when compared with the other blastomeres of the 2-cell embryo (p < 0.05). The variation in Cdc25c (p < 0.05) and Cdkn2d (p < 0.01) mRNA expression followed a similar trend to that of Axin1. In addition, the highest levels of expression of these three genes were detected in the same blastomere in the 2-cell embryo. We confirmed that there was an asymmetrical distribution pattern for Axin1, Cdc25c and Cdkn2d transcripts in 2-cell embryos. In conclusion, this study demonstrated clearly that there is embryonic asymmetry at the 2-cell stage and that these differentially expressed genes may result in differentiation in expression in embryo development.

Isolation and culture of bovine mammary epithelial stem cells.

Bovine mammary epithelial stem cells (MESCs) are very important in agricultural production and bioengineering. In the present study, we compared different isolation and culture methods for MESCs and observed their growth and differentiation characteristics. MESCs have an extremely weak proliferation capacity, and it is very difficult to obtain and prolong subculture of a bovine mammary epithelial stem cell line. We obtained some multipotent MESC aggregates that looked like spherical colonies. These colonies were only derived from suspension culture and were induced to differentiate into epithelial-like cells, myoepithelial-like cells and secretory cells and to establish a ductal-like structure. In contrast, MESCs cultured in adherent culture displayed low morphogenetic competence and only differentiated into epithelial-like cells. MESCs are often identified by testing their differentiation in vivo; however, herein, we have demonstrated the in vitro differentiation potential of bovine MESCs. In our study, beta 1-integrin and alpha 6-integrin which are expressed by human epidermal stem cells, were found in bovine, which shows that bovine MESCs share the same molecular signature as human MESCs.

Connexin37 mRNA expression in in vivo and in vitro mouse oocyte.

To evaluate gene expression of Connexin37 (Cx37) in oocytes from in vitro follicles at different stages, mouse preantral follicles were isolated and cultured for 12 days in vitro. Compared with in vitro follicles, follicles grown in vivo were collected at day 14 (d14), d16, d18, d20, d22 and d24 with the same stages for gene expression of Cx37 in oocytes. Our results showed that Cx37 mRNA increased along with follicular development, reached the highest level at the onset of antrum cavity formation and decreased after antrum formation in both in vivo and in vitro mouse oocytes. However, Cx37 mRNA was significant higher (p < 0.01) in in vitro cultured oocytes than in vivo oocytes. Moreover, significantly higher levels of Cx37 mRNA were found in oocytes from in vitro disrupted follicles (p < 0.01) and non-grown follicles (p < 0.05) than those from normal follicles with a similar size. These data determine temporal gene expression of Cx37 in oocytes from follicules at different stages and indicate that the gene expression level of Cx37 in oocytes could be evaluated as a criterion to the regulatory mechanism of Cx37 in an in vitro model.

Quantitative analysis of mitochondrial RNA in goat-sheep cloned embryos.

Mitochondria are the key generators of cellular ATP, and contain extranuclear genome-mitochondrial DNA (mtDNA). In the process of nuclear transfer (NT), heteroplasmic sources of mtDNA from a donor cell and a recipient oocyte are mixed in the cytoplasm of the reconstituted embryo. Previous studies showed inconsistent patterns of mtDNA inheritance in offspring and early fetuses generated through interspecies NT. The quantitative analysis of mitochondrial RNA (mtRNA) in interspecies cloned embryos is useful for better understanding the fate of two types of mitochondria. The components of nicotinamide adenine dinucleotide (NADH) dehydrogenase were coded by both nuclear DNA (nDNA) and mtDNA. The Subunit 1 (ND-1) is one of seven NADH dehydrogenase subunits coded by mtDNA. In present study, using real-time and reverse-transcription PCR, the copy number of species-specific ND-1 mRNA was examined in goat-sheep cloned embryos of various developmental stages, and was applied to evaluate the expression pattern of species-specific mtDNA. The results of showed that (1) the expression of mtDNA derived from goat fetal fibroblast (GFF) decreased from 1-cell stage (immediately after fused) to 2-cell stage, and could not be detected from 4-cell stage onward to blastocyst stage; (2) the expression of mtDNA derived from sheep oocyte was roughly constant from 1-cell stage to the 8-cell stage, increased gradually from 16-cell stage, and sharply at morula and blastocyst stage. Moreover, we strongly argued a mechanism, that is GFF-derived mitochondria were degraded for the depression of bioenergetic functions, and then selectively eliminated during the embryogenesis of goat-sheep cloned embryos.

[Knockdown of bcl-xL expression with RNA interference induces nasopharyngeal carcinoma cells apoptosis].

OBJECTIVE: To study the inhibition of the expression of bcl-xL gene induced by RNA interference in CNE-2Z cell line in addition to the inhibition of its proliferation and apoptotic induction. METHODS: Small interfering RNAs targeting bcl-xL gene were synthesized by using web design software provided by Amnion and the silencer short interfering RNA (siRNA) construction kit; fluorescein-labeled siRNAs were done by FAM-silencer siRNA labeling kit; siRNAs were transfected into CNE-2Z cells by using lipofectamine 2000 reagent; siRNA transfection efficiencies were analyzed by fluorescent microscopy; down-regulation of bcl-xL was detected by RT-PCR; thiazolyl blue (MTT) assay was used to assess the cell growth; apoptosis of CNE-2Z cells was analyzed by flow cytometry. RESULTS: Green fluorescence in the cells was seen clearly in FAM-labeled siRNA transfected group under the fluorescent microscope while none in the untransfected group. Different down-regulations of bcl-xL mRNA expression were found in the transfected groups. The expression of bcl-xL mRNA decreased by 10% - 70% in the siRNAs transfected CNE-2Z by RT-PCR scan analysis. The inhibitory rate of cell proliferation depended on time and concentrations to some extent. Different cell apoptosis could be induced by different concentrations of siRNA4. CONCLUSIONS: The synthesized siRNAs in vitro were able to down-regulate the expression of bcl-xL There were different capabilities of the specific siRNAs down-regulation. The transient transfected bcl-xL siRNA4 could effectively inhibit the growth of the cancer cells and induce theirs apoptosis. It was suggested that the siRNA technique provide not only an extremely powerful tool for the functional analysis of genome but also a new method for anti-nasopharyngeal carcinoma gene therapy.

Knockdown of survivin expression by small interfering RNA induces apoptosis in human breast carcinoma cell line MCF-7.

BACKGROUND & OBJECTIVE: survivin, a member of inhibitor of apoptosis protein (IAP) gene family, expresses in various human cancer tissues, and may facilitate tumor cell evasion from apoptosis, and promote aberrant mitotic progression. This study was to investigate cell proliferation and apoptosis status of human breast carcinoma cell line MCF-7 after knockdown of survivin. METHODS: Small interfering RNA was transfected into MCF-7 cells to inhibit expression of survivin. mRNA and protein levels of survivin were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. Proliferation inhibition rate of MCF-7 cells was analyzed by MTT assay. Cell apoptosis was assayed by flow cytometry (FCM). RESULTS: The expression of survivin in siRNA-transfected group decreased by 64% in comparison to untransfected group. After treatment of different concentrations of siRNA, proliferation inhibition rate and apoptosis rate of MCF-7 cells were increased. The highest proliferation inhibition rate was 60.9%, and the highest apoptosis rate was 29.0% after treatment of 200 nmol/L of siRNA. CONCLUSION: survivin siRNA might be a useful therapeutic agent for the treatment of breast carcinoma.