A combined method for detection of cell surface marker expression and bromodeoxyuridine (BrdU) uptake by epidermal cells in suspension

Xenobiotics in vitro: the influence of L-cystine, pantothenat, and miliacin on metabolic and proliferative capacity of keratinocytes

To investigate the effect of cell growth-stimulating agents on human epidermal keratinocytes, we exposed monolayers of normal human keratinocytes derived from foreskin to different concentrations of the amino acid L-cystine, the member of the vitamin B family D-pantothenat, the phytosterol miliacin, and a combination thereof in keratinocyte growth medium. As a test system for the metabolic capacity, we used the activity of mitochondrial deyhdrogenases as measured by XTT, and for the cell proliferation, we determined the BrdU-uptake. The additives, active ingredients of the hair growth drug PRIORIN, were added in the presence of fully supplemented keratinocyte growth medium or a deficient medium without L-cystine, L-methionine, L-histidin, D-pantothenat, epidermal growth factor, and bovine pituary gland extract. Deficient medium itself reduced the metabolic capacity of keratinocytes to 35% compared with keratinocytes in fully supplemented growth medium. In deficient medium cell, proliferation was not measurable. Increasing doses of L-cystine restored the reduced metabolic capacity from 46% (0.009 mg/L) to 54% (0.09 mg/L) and 92% (0.45 mg/L) in deficient medium. Addition of D-pantothenat (0.43 mg/L) enhanced the metabolic capacity to 150% only in fully supplemented growth medium, compared with untreated controls with growth medium. Miliacin (6 mg/mL) increased not only the metabolic capacity (162%) but also stimulated cell proliferation (215%) as measured by BrdU-uptake in growth medium. The combination of all three additives increased the metabolic capacity (245%) synergistically in growth medium. We were able to show effects of D-panthenol, L-lysine, and miliacin on proliferation and metabolic capacity of keratinocyte monocell culture, which was further increased by combination of the three substances. These basic results suggest a beneficial effect on keratinocyte growth and stimulation by products combining these substances (e.g., Priorin). Furthermore, this work emphasizes the suitability of keratinocyte monolayers for pharmacological testings.

B-cell proliferation activity of pectic polysaccharide from a medicinal herb, the roots of Bupleurum falcatum L. and its structural requirement

Pectic polysaccharide fraction (BR-2) containing pharmacologically active pectic polysaccharide, bupleuran 2IIc, which was prepared from a medicinal herb, the roots of Bupleurum falcatum L., was administered orally to C3H/HeJ mice for 7 consecutive days. Proliferative responses of spleen cells were enhanced in the presence of the purified pectic polysaccharide, bupleuran 2IIc, but another B-cell mitogen, lipopolysaccharide (LPS) did not give a similar effect. In vitro studies using spleen cells showed that bupleuran 2IIc also stimulated lymphocytes, depleted of adherent cells or T cells. Bupleuran 2IIc treatment increased subpopulation of CD25+ and surface immunoglobulin M-positive (sIgM+) lymphocytes. Non-specific immunoglobulin secretion of spleen cells treated with bupleuran 2IIc was increased according to the culture time, and coexistence of interleukin-6 (IL-6) enhanced the secretion more than that of bupleuran 2IIc alone. These results suggest that bupleuran 2IIc proliferates B cells in the absence of macrophages, and the resulting activated B cells are then induced into antibody-forming cells in the presence of IL-6. Among the structural region of bupleuran 2IIc, ramified region (PG-1), which consists of rhamnogalacturonan core rich in neutral sugar chain, showed the potent mitogenic activity suggesting it to be an active site. Mitogenic activity of bupleuran 2IIc was reduced in the presence of antipolysaccharide antibody (antibupleuran 2IIc/PG-1-IgG), which recognizes the ramified region of bupleuran 2IIc as the antigenic epitope. Mitogenic activity of bupleuran 2IIc was also reduced by the addition of beta-d-GlcpA-(1-->6)-beta-d-Galp-(1-->6)-d-Galp or beta-d-GlcpA-(1-->6)-d-Galp, which are a part of the epitopes of antibupleuran 2IIc/PG-1-IgG. These results suggest that the epitopes in bupleuran 2IIc act as active sites of the polysaccharide during mitogenic activity.

Bromodeoxyuridine: a diagnostic tool in biology and medicine, Part III. Proliferation in normal, injured and diseased tissue, growth factors, differentiation, DNA replication sites and in situ hybridization

This paper is a continuation of parts I (history, methods and cell kinetics) and II (clinical applications and carcinogenesis) published previously (Dolbeare, 1995 Histochem. J. 27, 339, 923). Incorporation of bromodeoxyuridine (BrdUrd) into DNA is used to measure proliferation in normal, diseased and injured tissue and to follow the effect of growth factors. Immunochemical detection of BrdUrd can be used to determine proliferative characteristics of differentiating tissues and to obtain birth dates for actual differentiation events. Studies are also described in which BrdUrd is used to follow the order of DNA replication in specific chromosomes, DNA replication sites in the nucleus and to monitor DNA repair. BrdUrd incorporation has been used as a tool for in situ hybridization experiments.

Enhancement of T-cell proliferation by PSK

Protein-bound polysaccharide, PSK, is a biological response modifier and influences various immunological functions in vivo, including those of T-cells. However, PSK has not been proved to stimulate proliferation of T-cells in vitro in contrast to various lines of evidence that indicate the proliferation of B-cells in vitro. PSK enhanced the proliferation of spleen cells in C3H/He and nude mice in vitro. In this study such proliferating cells were detected by monoclonal antibody to bromodeoxyuridine (BrdU) incorporated into DNA, and their subsets were determined by flowcytometry with monoclonal antibody to Thy1 as a cell surface marker of T-cells. When spleen cells from C3H/He mice were cultured with PSK for 3 days, the percentage of BrdU positive cells increased, and about 67% of BrdU positive cells were Thy1.2 positive. In addition, PSK also had the activity to enhance the proliferation in a T-cell-enriched fraction from spleen cells by nylon fiber columns as well as that in original spleen cells. These results suggest that PSK enhances the proliferation of T-cells as well as B-cells.

Detection of 5-bromo-2-deoxyuridine (BrdUrd) incorporation with monoclonal anti-BrdUrd antibody after deoxyribonuclease treatment

We studied the effects of deoxyribonucleases on the detection of 5-bromo-2-deoxyuridine (BrdUrd) by anti-BrdUrd monoclonal antibodies (mAbs). After DNase I treatment, BrdUrd was detected in cells fixed on slides with the anti-BrdUrd mAbs, B44 and BMC9318. The level of detection related to the degree of DNA digestion. DNA digestion of 25-75% resulted in levels of staining comparable to control preparations in which DNA was denatured by heating with formamide. Staining with the mAbs of DNase I-treated cells was abolished with S1 nuclease, a single-stranded DNA-specific nuclease. When exonuclease III was used after DNase I treatment, the staining intensity of cells fixed on slides increased, and BrdUrd could be detected in suspended cells by flow cytometry. Since this enzymatic method leading to the detection of BrdUrd does not involve cell loss, or destruction of either cellular morphology or epitope reactivity, as occurs with traditional DNA denaturation procedures, it is useful for kinetic studies of phenotypically mixed populations. Furthermore, staining with anti-BrdUrd mAb of cells treated with exonuclease III offers a simple approach to quantitation of apoptotic cells, in which an endogenous endonuclease is activated.

Effect of cyclosporins A, G, and H on normal and ichthyotic keratinocyte growth in culture

Cyclosporin A (CsA) was first used in organ transplantation and for the treatment of autoimmune disorders because of its strong immunosuppressant properties. Several laboratory studies have demonstrated that CsA exerts an inhibitory action on the growth of various cell types in culture, including human skin cells. Such an influence on epidermal keratinocytes, if not associated with the serious adverse effects of CsA medication, would be of interest for the treatment of hyperproliferative genodermatoses such as non-bullous congenital ichthyotic erythroderma (NBCIE). In our study, we used cyclosporin G (CsG) and H (CsH), analogues CsA, to examine the impact of these three cyclosporins on normal and ichthyotic keratinocyte growth in vitro. Epidermal cells were grown in a low-calcium, serum-free medium in the presence or absence of cyclosporins A, G or H (1-10 micrograms/ml). The effects of a 72-h exposure to the drugs were evaluated by cell counting, 3H-thymidine incorporation and cytofluorimetric analysis of the BrdU-labelled cell suspensions. Our findings indicate a dose-dependent keratinocyte growth inhibition by the three cyclosporins. The data obtained with the three quantitation methods were in agreement and the cyclosporin-mediated effects were observed in both normal and ichthyotic keratinocyte cultures. CsG and CsH proved less effective than CsA, which induced a highly significant reduction even at 1 microgram/ml. Our results suggest, however, that ichthyotic keratinocytes are more sensitive to CsG and H when compared with normal cells (50% inhibition of 3H-thymidine uptake at significantly lower doses). A possible therapeutic action of non-toxic doses of CsG and CsH on NBCIE and other hyperproliferative epidermal diseases needs to be confirmed clinically.

Two-colour immunoenzymatic technique using sequential staining by APAAP to evaluate two cell antigens

AIMS

To extend the alkaline phosphatase-antialkaline phosphatase (APAAP) immunoenzyme single stain method to a more generally applicable double stain technique. This will allow two primary antibodies of the same isotype of IgG and specifically the nuclear antigen bromodeoxyuridine (BRdU) to be evaluated with a cell surface antigen identifier.

METHOD

Sequential applications of the APAAP method showed two antigen sites by different dye couplings to a common alkaline phosphatase substrate, producing blue and red reaction products on the same slide. Antigens on different cell populations as well as those in different compartments of the same cell were analysed. The method allowed a surface antigen monoclonal to be revealed first, using an optimal fixative, before alcohol/gluteraldehyde fixation was used to start the second (BRdU) staining sequence.

RESULTS

An analysis of double staining of T lymphocyte subsets (CD4 and CD8) showed no significant difference in the order of application of the primaries (n = 10) and no significant difference from their corresponding single stain results (n = 50), confirming the validity of the technique where antigens are exclusively distributed. Other examples, including antigens distributed in different compartments of the same cell, displayed discrete staining which implied validity.

CONCLUSION

Double staining by APAAP with this technique seems to be applicable to those cases where antigens are exclusively distributed and includes cases where different compartments of the same cell are stained. It is especially useful in revealing antigens that require different fixation and preparation--that is DNA incorporated BRdU with a surface antigen. But it does seem to have a limited ability to produce a dual colour at a common site.

Proliferative and differentiative response of corneal and limbal epithelium to extracellular calcium in serum-free clonal cultures

An increasing concentration of extracellular Ca2+ ([Ca2+]e) consistently induces epithelial differentiation, but its effect on proliferation remains variable. We investigated the effect of [Ca2+]e on two different cell populations: the peripheral corneal (PC) and limbal (L) epithelia, the latter containing corneal stem cells. Primary clonal (18 cells/cm2) cultures from rabbit limbal and peripheral corneal epithelia were established in serum-free MCDB 151 medium containing growth-promoting agents and 0.03, 0.3, or 1.8 mM Ca2+. During early culture life, colony size and the BrdU labelling-index of L and PC, assayed on day 6, increased in response to increasing [Ca2+]e; cell attachment and colony-forming efficiency remained unchanged for both L and PC epithelia. These results indicate that increasing [Ca2+]e, under these defined conditions, stimulates the proliferation of transient amplifying cells, but does not stimulate the differentiation of stem cells into clonal proliferation. A 10-fold increase of the seeding density or prolongation of the culture up to day 14 or 21 changed the response to [Ca2+]e allowing better proliferation in lower [Ca2+]e. Only cells grown as a monolayer in 0.03 mM Ca2+ could still be passaged on day 14, whereas cells in higher [Ca2+]e showed increasing stratification and cell detachment and could not be passaged. Normal cellular differentiation accessed by the expression of a cornea-type K3 keratin, recognized by the monoclonal antibody AE-5, was enhanced by increasing [Ca2+]e. Abnormal differentiation featured by the formation of cornified envelopes was only observed in higher [Ca2+]e. These results indicate that [Ca2+]e promotes the proliferation of relatively undifferentiated transient amplifying cells under clonal, serum-free culture conditions. Factors that enhance differentiation, such as seeding density or prolonged culture life, can modify this response and allow better proliferation in low [Ca2+]e.

Simultaneous flow cytometric detection of cellular c-myc protein, incorporated bromodeoxyuridine, and DNA

We describe a multivariate flow cytometric technique for simultaneous analysis of specific nuclear protein, bromodeoxyuridine (BrdUrd) incorporated into DNA and DNA content in single cells in suspension. The procedure involves fixation of BrdUrd-exposed cells with paraformaldehyde, heat denaturation of cellular DNA, followed by sequential immunochemical reactions to label incorporated BrdUrd and nuclear protein, and finally staining of total DNA with propidium iodide. The cells are analyzed flow cytometrically and multivariate data acquired in list mode to facilitate analyses of heterogeneous subpopulations. We applied this technique to measure c-myc protein, incorporated BrdUrd, and DNA content in subpopulations present in a recombinant Chinese hamster ovary (CHO) cell line carrying approximately 800 copies of murine c-myc sequences under control of an inducible heat shock promoter.