Cell culture

About: Cell culture is a research topic. Over the lifetime, 133361 publications have been published within this topic receiving 5364150 citations. The topic is also known as: cell culture techniques.

Efficient generation of hepatocyte-like cells from human induced pluripotent stem cells.

Abstract: Human induced pluripotent stem (iPS) cells are similar to embryonic stem (ES) cells, and can proliferate intensively and differentiate into a variety of cell types However, the hepatic differentiation of human iPS cells has not yet been reported In this report, human iPS cells were induced to differentiate into hepatic cells by a stepwise protocol The expression of liver cell markers and liver-related functions of the human iPS cell-derived cells were monitored and compared with that of differentiated human ES cells and primary human hepatocytes Approximately 60% of the differentiated human iPS cells at day 7 expressed hepatic markers alpha fetoprotein and Alb The differentiated cells at day 21 exhibited liver cell functions including albumin Asecretion, glycogen synthesis, urea production and inducible cytochrome P450 activity The expression of hepatic markers and liver-related functions of the iPS cell-derived hepatic cells were comparable to that of the human ES cell-derived hepatic cells These results show that human iPS cells, which are similar to human ES cells, can be efficiently induced to differentiate into hepatocyte-like cells

Apoptosis induced in Jurkat cells by several agents is preceded by intracellular acidification

Abstract: We have previously shown that in neutrophils deprived of granulocyte colony-stimulating factor, apoptosis is preceded by acidification and that the protection against apoptosis conferred on neutrophils by granulocyte colony-stimulating factor is dependent upon delay of this acidification. To test the hypothesis that acidification could be a general feature of apoptosis, we examined intracellular pH changes in another cell line. Jurkat cells, a T-lymphoblastoid line, were induced to undergo apoptosis with anti-Fas IgM, cycloheximide, or exposure to short-wavelength UV light. We found that acidification occurred in response to treatment with these agents and that acidification preceded DNA fragmentation. Jurkat cells were also found to possess an acid endonuclease that is active below pH 6.8, compatible with a possible role for this enzyme in chromatin digestion during apoptosis. Incubation of the cells with the bases imidazole or chloroquine during treatment with anti-Fas antibody or cycloheximide or after UV exposure decreased apoptosis as assessed by nuclear morphology and DNA content. The alkalinizing effect of imidazole and chloroquine was shown by the demonstration that the percentage of cells with an intracellular pH below 6.8 after treatment with anti-Fas antibody, cycloheximide, or UV was diminished in the presence of base as compared with similarly treated cells incubated in the absence of base. We conclude that acidification is an early event in programmed cell death and may be essential for genome destruction.

Immunofluorescence and Herpes-Type Virus Particles in the P3HR-1 Burkitt Lymphoma Cell Line

Abstract: A subline of the P3 (Jijoye) Burkitt lymphoma cell line, designated P3HR-1, initially contained 1 to 5% of cells which were positive by indirect immunofluorescence with selected human sera After 4 months of propagation, this cell line regularly showed 15 to 40% reactive cells Antigen(s) in the cell line which was reactive by immunofluorescence was similar or identical to that found in several other Burkitt tumor cell lines in previous studies When the cells were incubated at 35 or 32 C for 9 to 15 days without refeeding, more than 50% of the cells became immunofluorescence-positive Thirteen different cultures of P3HR-1 cells, which contained up to 75% immunofluorescence-positive cells, were thin-sectioned and examined by electron microscopy The percentage of cells containing herpes-type virus particles in the cultures varied from <3 to 78% There was generally a good correlation between the number of immunofluorescent cells and the number of cells containing virus particles The number of virus particles per cell section ranged from 1 to more than 100 These results strongly support the hypothesis that the immunofluorescent antigen is related to the presence of the herpes-type virus particle in the cells

Genetic determinants of p53-induced apoptosis and growth arrest.

Abstract: Previous studies have suggested that expression of p53 in cancer cells can result in either growth arrest or apoptosis. Accordingly, expression of p53 in a series of colorectal cancer cell lines yielded growth arrest in some lines (A-lines) and apoptosis in others (D-lines). To investigate the basis of this difference, we evaluated the role of p21WAF1/Cip1, a known mediator of p53-induced growth arrest. Inactivation of p21 by homologous recombination converted an A-line to a D-line, suggesting that p21 could protect cells from apoptosis. However, examination of p53-induced p21 expression in naturally occurring D-lines and A-lines demonstrated that the induction of p21 could not account for the differential response to p53. Moreover, when a D-line was fused to an A-line, the resulting hybrid cells underwent apoptosis in response to p53, indicating that the apoptosis pathway was dominant over the growth arrest pathway. Therefore, the apoptotic response to p53 in colorectal cancer cells is modulated by at least two factors: p21-mediated growth arrest that can protect cells from apoptosis in A-cells, and trans-acting factors in D-cells that can overcome this protection, resulting in cell death.

Induction of interleukin 2 receptor gene expression by p40x encoded by human T-cell leukemia virus type 1.

Abstract: Human T-cell leukemia virus type 1 (HTLV-1) is an etiologic agent of adult T-cell leukemia (ATL). A viral product, p40x, encoded by the pX sequence of HTLV-1 is a trans-acting transcriptional activator of the long terminal repeat (LTR) and has been suspected of involvement in leukemogenesis, activating the cellular genes. The cellular interleukin-2 (IL-2) and its receptor (IL-2R), the latter of which is expressed on ATL leukemic cells, were shown to be transiently induced by transfection of plasmid pMTPX expressing pX in two T-cell lines, Jurkat and HSB-2, but not in other human T- or B-cell lines. The cell type specificity of IL-2R induction by pX expression was the same as that by phytohaemagglutinin/phorbol ester activation, indicating the requirement for some specific cellular factors or a certain state of cellular differentiation. Induction of IL-2 and IL-2R at mRNA level was also demonstrated in transfected cells. Transfections with mutants of pMTPX in which the open reading frames for p40x, p27x-III and p21x-III were inactivated indicated that p40x alone was sufficient for induction of the IL-2R in inducible cells. This induction of the IL-2R by p40x of HTLV-1 may contribute to preferential proliferation of HTLV-1 infected cells at an early stage of ATL development and eventually increase the number of putative target cells for malignant transformation.