Enhancement of human amniotic cell growth by Ficoll-Paque gradient fractionation

PRMT1-RBM15 axis regulates megakaryocytic differentiation of human umbilical cord blood CD34+ cells

Protein arginine methyltransferase 1 (PRMT1) serves pivotal roles in various cellular processes. However, its role in megakaryocytic differentiation has not been clearly reported. The aim of the present study was to explore the role of the PRMT-RNA binding motif protein 15 (RBM15) axis in human MK differentiation and the feasibility of targeting PRMT1 for leukemia treatment. In the present study, PRMT1 was overexpressed and the RBM15 protein was knocked down in human umbilical cord blood cluster of differentiation (CD)34⁺ cells and the cells were then cultured in megakaryocytic differentiation medium. Flow cytometry was used to analyze CD41 and CD42 double-positive cells, as well as the protein expression levels of PRMT1 and RBM15. The results demonstrated that human cord blood CD34⁺ cells differentiate into mature MKs in high thrombopoitin medium, as demonstrated by CD41 and CD42 expression. Overexpression of PRMT1 in human umbilical cord blood CD34⁺ cells blocked the maturation of megakaryocytic cells. Knockdown of RBM15 by short hairpin RNA produced less mature MKs. PRMT1 inhibitor rescued PRMT1-blocked megakaryocytic differentiation. These results provide evidence for a novel role of PRMT1 in the negative regulation of megakaryocytic differentiation. PRMT1 may be a therapeutic target for leukemia treatment.

Experimental in vitro and in vivo studies of epithelium formation on biomaterials seeded with isolated respiratory cells

Extensive tracheal defects after intensive care medicine, trauma, or large resections in tumor surgery remain a major challenge in plastic and reconstructive surgery. Defects that cannot be satisfactorily treated by complicated and costly reconstructive techniques reveal a need for an alloplastic tracheal replacement. Recent experimental and clinical studies in the development of alloplastic tracheal prostheses proved that the lack of an epithelial lining on the luminal surfaces and inadequate biophysical properties and shapes of the prostheses were the main causes for failure of these prostheses. In this study a cell-seeding technique has been used. Adhesion, spreading, and differentiation of seeded mucosa cells on biomaterials in vitro were observed by scanning electron microscopy (SEM). Chemical properties and surface structure of the material influenced the differentiation process. Epithelium formation of incorporated tracheal prostheses was tested in animal experiments. Isolated respiratory cells were seeded into implanted tubular prostheses of porous polyurethane or expanded polytetrafluorethylene. Light microscopy and SEM showed the tendency of epithelium formation on the surface of the lumen. Vigorous cell layers, predominantly as multiple cell layers of squamous epithelium, were observed. Ciliated or mucus cells were not detected. It can be stated that the epithelium formation on incorporated porous implants is possible. Further studies of the stability and the differentiation process of the epithelium on such implants is needed before an introduction of tracheal replacements into the clinical practice can be considered.

Expression of tracheal differentiated functions in serum-free hormone-supplemented medium

Most dissociated airway epithelial cells in culture express few of their in vivo functions and only to a limited degree. In this report, we demonstrate that hamster tracheal epithelial (HTE) cells cultured on a collagen gel substratum in a serum-free hormone-supplemented medium differentiate to cilia-beating and mucus-secreting cell types. The medium is Ham's F-12 supplemented with insulin, epidermal growth factor, transferrin, hydrocortisone, cholera toxin, bovine hypothalamus extract, and vitamin A. Under these culture conditions, HTE cells exhibit a growth rate of 24 h/population doubling and reach confluency, at a density of 2-5 X 10(4) cells/cm2, within 2 weeks. Both the collagen gel substratum and vitamin A of this culture system are important to the growth and differentiation of HTE cells in vitro. Evidence of HTE cell differentiation has been obtained at both the ultrastructural and the histochemical levels. In addition, a variety of biochemical studies (gel filtration, ion exchange column chromatography, enzyme digestion, nitrous acid treatment, and composition analysis) indicate the production of mucin-like glycoprotein in the HTE cultures. The levels of mucin-like glycoprotein were found to closely correlate with the histochemically quantitated levels of the mucous cell type. Kinetic studies demonstrate that HTE cells rapidly lose their differentiated features during the attachment stage of primary culture but redifferentiation occurs after the cultures reach confluency. The ability of HTE cells to grow and differentiate in this serum-free culture system in the absence of other cell types should greatly facilitate the study of mucociliary functions in vitro.

Reduction of sera requirements in amniotic fluid cell culture

Reduction in serum requirement for culture of primary human amniotic fluid cells can be achieved by the addition of 10 growth-promoting factors to the nutrient medium. This supplemented medium preserves cell types normally found in amniotic fluid cell cultures supplemented with 20-30 per cent fetal bovine serum. The volume of amniotic fluid required to initiate culture can be as little as 1 ml. Amniotic fluid samples contaminated with red blood cells with no visible clot also grow well in the low serum medium. Cell-free amniotic fluid combined with equal parts of supplemented medium is useful in initiating cell culture.

Isolation of large numbers of dispersed human pituitary adenoma cells obtained by aspiration

Since the extent of in vitro experiments with human pituitary adenoma cells is often limited by the small number of cells isolated from surgical specimens, ways to obtain more cells are of interest. In this study we made use of tumor tissue removed by aspiration through a suction tube during transsphenoidal surgery. Fifteen out of 28 adenomas could be dispersed without enzymatic treatment. The other 13 adenomas were mildly treated with Dispase. The large number of red blood cells present in the suction tube were removed by Ficoll-Isopaque density centrifugation. More than 90% of the adenoma cells were recovered from the interphase fraction. This material, in contrast with fragments obtained with a forceps, yielded 35.9 (+/-9.0) X 10(6) cells (mean +/- SE, n = 28). Usually less than 10% of these cells were mononuclear leucocytes. Pituitary hormones other than those hypersecreted in vivo were not found in the incubation media; only small amounts of LH were found in 5 out of 25 adenomas. A linear relationship was found between cell concentration and hormone secretion, both for PRL and GH. In vitro hormone secretion by the adenoma cells was in good agreement with in vivo dynamic tests. In longterm culture, GH and ACTH secretion by the adenoma cells declined, while PRL secretion was fairly constant. It is concluded that large numbers of dispersed pituitary adenoma cells can be obtained from the material removed by suction during transsphenoidal operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Growth and differentiation of hamster tracheal epithelial cells in culture

The purpose of these studies was to define culture conditions that support growth and differentiation of normal epithelial cells obtained from hamster tracheas. Epithelial cells from tracheas of adult hamsters were collected using enzymatic procedures and cultured under various conditions. The medium used consisted of a 1:1 mixture of medium 199 and Dulbecco's modified Eagle's medium with 2% fetal bovine serum, which was conditioned by mouse 3T3 cells before use. Insulin, transferrin, hydrocortisone, epidermal growth factor, and an extract from bovine hypothalamus were used as supplements. When seeded on uncoated or collagen-coated tissue culture dishes, the hamster cells grew only poorly. When the cells were seeded on collagen gels, however, rapid and prolonged growth ensued. The cultures had a population doubling time of 20 hr and a colony-forming efficiency of 7-10%, and they could be grown for up to three passages. Growth was dependent on the presence of transferrin, insulin, epidermal growth factor, and 3T3 conditioning factors in the medium. The latter could be omitted if the concentration of serum was increased. Less important for growth was the presence of hydrocortisone and bovine hypothalamus extract. In contrast to results with tracheal epithelial cells from adult rabbits, rats, and mice, differentiation into ciliated cells regularly occurred in cultures of cells derived from hamster tracheas. The appearance of ciliated cells in the cultures was dependent on the presence of collagen gel as a substratum and of 3T3 conditioning factors in the medium. In addition, there were numerous cells that contained electron-dense cytoplasmic granules. The granules were not stained by dialyzed iron, which stains acidic glycoproteins, but were stained positively by periodic acid-Schiff reagents and the periodic acid-thiocarbohydrazide-silver proteinate method, suggesting the presence of secretory granules containing neutral glycoproteins. A similar staining pattern was observed for the secretory granules of intact hamster tracheas. The culture system described supports growth and cellular differentiation of normal tracheal epithelial cells of hamsters. We believe therefore that it will be a useful model for studying the regulation of tracheal cell function on the cellular and biochemical level.

Human amniotic fluid cells grown in a hormone-supplemented medium: suitability for prenatal diagnosis

A new supplemented medium has been developed to improve human amniotic fluid cell growth and to reduce the dependence on exogenously added serum. The medium consists of a mixture of Ham's F12 medium and Dulbecco's modified Eagle's medium supplemented with Hepes, antibiotics, and 10 growth-promoting factors at 4% fetal bovine serum. Good clonal growth is achieved consistently in 8--13 days and is associated with large numbers of metaphase cells. Primary clones may be analyzed directly, thereby reducing difficulty with interpretation of chromosomal mosaicism. This medium could also be used for cultivation of fetal solid tissues and peripheral blood cultures of lymphocytes.