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Growth hormone (GH) plays important roles in oocyte development and facilitates the successful production of competent oocytes in many species both in vivo and in vitro. However, the mechanism of GH action on oocyte maturation is not well known. In this paper, the temporospatial messenger ribonucleic acid expression patterns of GH and several other GH-related factors were quantitatively analyzed in porcine cumulus–oocytes complex throughout in vitro maturation (IVM). GH expression was decreased in oocytes during IVM while absent in cumulus cells. GH receptor, insulin-like growth factor-1 (IGF-1), and IGF-1 receptor expressions were also downregulated in oocytes. In cumulus cells, the expression of IGF-1 decreased significantly while IGF-1 receptor expression remained constant. The transcripts of Janus kinase 2 increased in both oocytes and cumulus cells during IVM. The current precise gene expression information provides further evidence to explain the complex network of GH signaling involved in IVM of porcine oocyte.
We evaluated the possibility of deriving primary cell cultures from tissue biopsies taken in field conditions from six threaten endemic Chilean species of free-ranging mammals. Biopsies were taken either by ear punching or darts fired to animals and hold in hypothermic conditions (4° C) in defined salt solution for time periods ranging from 0 to 7 d before biopsy samples reached the cell culture laboratory. Previously, holding times were evaluated in experimental cows in controlled conditions. Two enzymatic treatments, collagenase alone or collagenase followed by tripsin, were used to disaggregate tissues for cell culture. We found that ear notches and dart-derived biopsies can be storaged at 4° C for 1 wk and still yield primary cultures. For dart-derived biopsies, there was an invert correlation between length of cold storage and cellular viability in culture. Healthy fibroblast cell lines were obtained in 92% of the biopsies taken despite the origin (punch or biopsy). We are not aware of similar study for free-ranging animals, especially for the use of darting system to biopsy wild terrestrial mammals, we believe that our results could help for a more widespread implementation of these procedures in the practice of ex situ conservation
One of the major risks in cell culture laboratories is the misidentification and cross-contamination of cell lines. Several methods have been used to authenticate cell lines, including isoenzyme profiling, the test suggested by European Farmacopeia, which is performed at the Tissue Culture Centre in Brescia. However, this method displays several disadvantages, such as high variability and low reproducibility, and it is time consuming and requires high cell concentrations to be performed. Therefore, an alternative method has been developed to confirm the specie of origin of 27 different animal cell cultures. A polymerase chain reaction (PCR)–restriction fragment length polymorphism (RFLP) assay was optimized, based on the use of a pair of primers that anneal to a portion of the cytochrome b gene in all the species. The amplification product was digested with a panel of six restriction enzymes, and the pattern derived was resolved on 3% high-resolution agarose gel. For 23 species, this protocol produced a unique restriction pattern, and the origin of these animal cells resulted to be confirmed by this analysis. Furthermore, results indicate that cytochrome b PCR-RFLP was able to amplify target sequences using very low amounts of deoxyribonucleic acid (DNA). Its sensitivity in detecting interspecies, cross-contamination was comparable to that of isoenzyme analysis (contaminating DNA should represent at least 10% of the total DNA). For 4 of the 27 species (sheep, dog, Guinea pig, and Rhesus monkey) the observed pattern, even if highly reproducible, showed additional bands; for these species, specific PCR was also performed.
The symbiotic octocoral Sinularia flexibilis is a producer of potential pharmaceuticals. Sustainable mass production of these corals as a source of such compounds demands innovative approaches, including coral cell culture. We studied various cell dissociation methodologies and the feasibility of cultivation of S. flexibilis cells on different media and cell dissociation methodologies. Mechanical dissociation of coral tissue always yielded the highest number of cells and allowed subsequent cellular growth in all treatments. The best results from chemical dissociation reagents were found with trypsin-ethylene diamine tetraacetic acid. Coral cells obtained from spontaneous dissociation did not grow. Light intensity was found to be important for coral cell culture showing an enduring symbiosis between the cultured cells and their intracellular algae. The Grace's insect medium and Grace's modified insect medium were found to be superior substrates. To confirm the similarity of the cultured cells and those in the coral tissue, a molecular test with Internal Transcribed Spacer primers was performed. Thereby, the presence of similar cells of both the coral cells and zooxanthella in different culture media was confirmed.
We have previously described a model to engineer three-dimensional (3-D) heart muscle in vitro. In the current study, we extend our model of 3-D heart muscle to engineer a functional cell-based cardiac pressure generating construct (CPGC). Tubular constructs were fabricated utilizing a phase separation method with chitosan as the scaffolding material. Primary cardiac cells isolated from rat hearts were plated on the surface of fibrin gels cast in 35 mm tissue culture dishes. CPGCs (N=8) were formed by anchoring the tubular constructs to the center of the plate with primary cardiac cells seeded in fibrin gels wrapped around the tubular constructs. Intraluminal pressure measurements were evaluated with and without external electrical stimulation and histological evaluation performed. The fibrin gel spontaneously compacted due to the traction force of the cardiac cells. By 14 d after original cell plating, the cardiac cells had completely formed a monolayer around the tubular construct resulting in the formation of a cell-based CPGC. The spontaneous contractility of the CPGC was macroscopically visible and resulted in intra-luminal pressure spikes of 0.08 mmHg. Upon electrical stimulation, the CPGCs generated twitch pressures of up to 0.05 mmHg. In addition, the CPGC constructs were electrically paced at frequencies of up to 3 Hz. Histological evaluation showed the presence of a continuous cell monolayer around the surface of the tubular construct. In this study, we describe a novel in vitro method to engineer functional cell-based CPGCs and demonstrate several physiological metrics of functional performance.
The Aedes albopictus Aa23 cell line, which is persistently infected with Wolbachia pipientis strain wAlbB, tends to grow as aggregated clusters of cells that are difficult to disperse for conventional quantification based on cell number. We used A. albopictus C7-10 cells to validate conversion of methylthiazole tetrazolium (MTT) to a colored formazan product with respect to incubation time, cell number over a 40-fold range, and metabolic activity as cells enter stationary phase. Using this assay, we showed that the doubling time of Aa23 cells increases from about 45 h early after plating to more than 70 h as the cells reach stationary levels. Growth of Aa23 cells proceeds at similar rates in the presence or absence of tetracycline concentrations that decrease the abundance of Wolbachia. Insofar as the MTT assay reflects mitochondrial function, our results indicate that, in Aa23 cells, abundance of intracellular Wolbachia has no measurable effect on mitochondrial activity in the presence of tetracycline.
Breast and ovarian cancer patients with germline mutations in BRCA1 respond more favorably to initial chemotherapy. We previously reported that cells from women carrying the BRCA1 185delAG founder mutation undergo an enhanced caspase-3-mediated apoptotic response. Here, we report on the transient and stable transfection of cDNA coding for the putative truncated protein product of the BRCA1 185delAG mutant gene into BRCA1 wild-type human ovarian surface epithelial cells and ovarian cancer cells, resulting in cells with a heterozygous background containing two BRCA1 wild-type alleles and the BRCA1 185delAG transcript. The BRCA1 185delAG truncation (BRAt) protein did not alter epithelial cell morphology or induce tumorigenesis. However, upon treatment with staurosporine, BRAt cells showed increased levels of active caspase-3 and increased cleavage of caspase-3 substrates, PARP and DFF45. Additionally, XIAP and cIAP-1 protein are at reduced levels in untreated BRAt cells as compared to control cells. BRAt also reduced levels of phosphorylated Akt and overexpression of activated Akt in BRAt cells restored caspase-3 activity to that seen in wild-type cells. Further, BRAt expression increased chemosensitivity in platinum-resistant ovarian cancer cells. Taken together, our data demonstrate that truncated proteins arising from BRCA1 185delAG mutation increase Akt-mediated apoptosis, suggesting a possible mechanism by which ovarian cancer patients with this germline BRCA1 mutation may respond better to initial chemotherapy.
Embryonic stem (ES) cells have the potential to differentiate into various cell types of the three germ layers. They are therefore a useful cell source for transplantation and tissue engineering. In the present paper, we studied the influences of ascorbic acid (AA), dexamethasone (Dex), and 17β-estradiol (E2) on the osteogenic differentiation of ES cells. Differentiation into the osteoblastic phenotype was demonstrated by the appearance of osteoblastic markers such as alkaline phosphatase (ALP), the transcription factor core binding factor alpha 1 (Cbfa1), and osteocalcin, which were detected by immunohistochemistry. Bone nodule formation, including the deposition of collagen fibrils and matrix mineralization, was studied by transmission electron microscopy. In all our cultures, a progressive upregulation of ALP activity was observed, followed by a decline after 21 d of culture. Cbfa1 was first detected after 14 d in culture and increased during the culture time. The addition of E2 resulted in a decrease in the formation of bone-like nodules in the embryoid bodies (EBs) compared with the EBs cultured in the presence of AA and AA supplemented with Dex. An increased osteocalcin concentration was observed in the EBs cultured with Dex and E2 compared with the EBs cultured in a control medium. EBs cultured in the presence of E2 resulted in a culture with a high amount of osteoblast-like cells not entrapped in bone-like nodules, creating the possibility to obtain a purified osteoblast population for bone tissue engineering.
Galanin is a 29-amino-acid neuropeptide expressed in dorsal root ganglion (DRG) neurons which is thought to play a role in modulation of nociception in neuropathic states. Activation of galanin receptor 2 (GalR2) plays a pronociceptive role and enhances capsaicin-induced nociception in the periphery. GalR2 and vanilloid receptor 1 (VR1) are co-expressed in DRG neurons. Capsaicin evokes acute pain via activation of VR1 expressed in primary sensory neurons. It is not known to what extent galanin and its receptor GalR2 expression is regulated by capsaicin in DRG neurons. Effects of acute (4 h) or chronic (4 d) treatment with capsaicin at different concentrations (0.01, 0.1, 1 μmol/L) on galanin and GalR2 expression in primary cultured DRG neurons were investigated in the present study. Our results showed that acute exposure of high concentration capsaicin (1 μmol/L) increased galanin expression, whereas chronic exposure of low concentration capsaicin (0.01, 0.1 μmol/L) promoted galanin expression. Only chronic exposure of 0.1 μmol/L concentration cap-saicin could elevate GalR2 expression, whereas capsaicin did not have this effect at any other conditions in this experiment. These results indicated that certain concentrations or exposure time of capsaicin stimulation may be relevant to upregulation of galanin and its receptor GalR2 expression in DRG cultures suggesting a response to peripheral neuronal stimulation. And also, capsaicin-induced GalR2 expression may be also modulated by capsaicin-induced galanin expression. The possible significance of the neurotransmission of nociceptive information involved in galanin or GalR2 expression caused by capsaicin is still to be clarified.
Nitric oxide (NO) is an important mediator in many (patho)physiological processes including inflammation and skin cancer. A key transducer in NO signaling is the soluble guanylyl cyclase (sGC) that catalyzes the formation of guanosine 3′,5′-cyclic monophosphate (cGMP). The basic mechanism of NO-cGMP signaling in melanocytic cells is, however, not well elucidated. A setback for such studies is the limited availability of patient-derived melanocytes. Here, we report that immortalized human normal and vitiliginous cell lines generated via cell transfection with human papilloma virus 16 genes E6 and E7 express NO synthase and guanylyl cyclase isoforms and the multidrug resistance-associated proteins 4 and 5 as selective cGMP exporters. Donors of NO (e.g., the NONOate (Z)-1-[N-(3-ammoniopropyl)-N-(n-propyl)ami-no]diazen-1-ium-1,2-diolate (PAPA-NO) and reactive nitrogen oxygen species (RNOS) like 3-morpholino-sydnonimine (SIN-1) as a donor of peroxynitrite as well as YC-1 as a NO-independent sGC stimulator increased intracellular cGMP levels in immortalized melanocytes (up to eightfold over controls), indicating the expression of functional sGC in these cells. PAPA-NO and SIN-1 also reduced the attachment of immortalized melanocytes to extracellular matrix (ECM) components like fibronectin which was dependent on cellular melanin content and cGMP. Such effects on melanoma cells were positively related to metastatic potential and were cGMP independent. Intriguingly, nonpigmented metastatic melano-ma cells were more sensitive to exogenous sources of RNOS than of NO. Thus, immortalized melanocytes can be used as a tool for further research on differences in cell signaling between the different melanocytic lineages in particular towards impairment of cell-ECM adhesion by NO or RNOS, which may be important in metastasis and vitiligo pathogenesis.
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