Localization of stem cell factor (SCF) and c-kit mRNA in human placental tissue and biological effects of SCF on DNA synthesis in primary cultured cytotrophoblasts

Appropriate citation of placenta cell lines 3A(tPA-30-1) and 3A-sub E [post crisis of 3A(tPA-30-1)] in medical literature

Introduction

To determine how often placenta cell lines 3A (tPA-30-1) and 3A-sub E [post crisis of 3A (tPA-30-1)] are appropriately cited, or identified, as "term"-gestation placental cell lines in medical literature.

Methods

We performed a literature search on two databases, PubMed and One Search, using the terms "3A (tPA-30-1)," "3Asub-E," "3AsubE," "tPA-30-1," "tPA30-1," and "3A AND (placenta OR placental OR trophoblast OR trophoblastic) AND (cell OR line OR cell line)." Of the 218 citations retrieved, 181 were excluded due to duplication, article content irrelevance or lack of access to a full manuscript. The remaining 37 citations were thoroughly reviewed for 1)the presence of a full citation as designated by the supplier, and 2)the identification of the placental lines as "term."

Results

Of the 37 eligible citations included in the study, five demonstrated complete identifications of the placental cell lines of interest, while 32 demonstrated partial identifications that failed to match the designations provided by the manufacturer. Furthermore, of the 37 citations, eight accurately identified the cell lines as "term," while 27 lacked any description of gestational age, and two incorrectly identified them as "first trimester" cell lines. Overall, only three citations contained both a full citation and correct identification as a "term" placenta cell line.

Discussion

Only 5 of the 37 (13.5%) publications demonstrated a complete citation and only 8 publications accurately identified the gestational age of the placenta cell line as "term". Such findings confirm the need for a representative set of standards for the documentation of cell lines to improve the quality of publications in the scientific community.

Unremitting cell proliferation in the secretory phase of eutopic endometriosis: involvement of pAkt and pGSK3β

OBJECTIVE

Endometriosis is linked to altered cell proliferation and stem cell markers c-kit/stem cell factor (SCF) in ectopic endometrium. Our aim was to investigate whether c-kit/SCF also plays a role in eutopic endometrium.

DESIGN

Eutopic endometrium obtained from 35 women with endometriosis and 25 fertile eumenorrheic women was analyzed for in situ expression of SCF/c-kit, Ki67, RAC-alpha serine/threonine-protein kinase (Akt), phosphorylated RAC-alpha serine/threonin-protein kinase (pAkt), Glycogen synthase kinase 3 beta (GSK3β), and phosphorylated glycogen synthase kinase 3 beta (pGSK3β), throughout the menstrual cycle.

RESULTS

Expression of Ki67 and SCF was higher in endometriosis than in control tissue (P < .05) and greater in secretory rather than proliferative (P < .01) endometrium in endometriosis. Expression of c-kit was also higher in endometriosis although similar in both phases. Expression of Akt and GSK3β was identical in all samples and cycle phases, whereas pAkt and pGSK3β, opposed to control tissue, remained overexpressed in the secretory phase in endometriosis.

CONCLUSION

Unceasing cell proliferation in the secretory phase of eutopic endometriosis is linked to deregulation of c-kit/SCF-associated signaling pathways.

Immunohistochemical expression of endothelial nitric oxide synthase and C-kit in the placenta of complete hydatidiform mole

Complete hydatidiform mole is an abnormal conceptus characterized by hydropic villi accompanied by proliferating trophoblasts. Its pathogenesis is largely unknown. Endothelial nitric oxide synthase is induced by vascular endothelial growth factor and has been implicated in the pathogenesis of preeclampsia and other physiologic conditions in the placenta. C-kit is the tyrosine kinase receptor and is involved in tumor formation elsewhere in the body. Using standard immunohistochemical protocols, we studied the expression of C-kit and endothelial nitric oxide synthase in the placenta of 10 patients with complete hydatidiform mole. Cytoplasmic and nuclear staining with endothelial nitric oxide synthase was identified in the cytotrophoblast and intermediate trophoblast layers in all cases, with high staining in 7/10 and 6/8 cases, respectively. Minimal staining is identified in the syncytiotrophoblast layer. Hofbauer stromal cells were identified in 9 cases and showed low staining intensity in 7/9 cases. Cytoplasmic C-kit staining was diffuse and of low intensity. The cytotrophoblast, the syncytiotrophoblast, intermediate trophoblast, and the stromal cells had low C-kit staining intensity in 8/10, 8/10, 7/9, and 5/9 cases. These results indicate that C-kit and endothelial nitric oxide are expressed in the placentas of complete hydatidiform mole and may play a role in the pathogenesis of trophoblastic proliferation in this condition.

Ghrelin inhibits the proliferative activity of immature Leydig cells in vivo and regulates stem cell factor messenger ribonucleic acid expression in rat testis

Ghrelin has emerged as putative regulator of an array of endocrine and nonendocrine functions, including cell proliferation. Recently, we provided evidence for the expression of ghrelin in mature, but not in undifferentiated, Leydig cells of rat and human testis. Yet testicular actions of ghrelin, other than modulation of testosterone secretion, remain unexplored. In the present study we evaluated the effects of ghrelin on proliferation of Leydig cell precursors during puberty and after selective elimination of mature Leydig cells by treatment with ethylene dimethane sulfonate. In these settings, intratesticular injection of ghrelin significantly decreased the proliferative activity of differentiating immature Leydig cells, estimated by 5-bromodeoxyuridine labeling. This response was selective and associated, in ethylene dimethane sulfonate-treated animals, with a decrease in the mRNA levels of stem cell factor (SCF), i.e. a key signal in spermatogenesis and a putative regulator of Leydig cell development. Thus, the effects of ghrelin on SCF gene expression were evaluated. In adult rats, ghrelin induced a significant decrease in SCF mRNA levels in vivo. Such an inhibitory action was also detected in vitro using cultures of staged seminiferous tubules. The inhibitory effect of ghrelin in vivo was dependent on proper FSH input, because it was detected in hypophysectomized rats only after FSH replacement. Overall, it is proposed that acquisition of ghrelin expression by Leydig cell precursors during differentiation may operate as a self-regulatory signal for the inhibition of the proliferative activity of this cell type through direct or indirect (i.e. SCF-mediated) mechanisms. In addition, we present novel evidence for the ability of ghrelin to modulate the expression of the SCF gene, which may have implications for the mode of action of this molecule in the testis as well as in other physiological systems.

Quantitative analysis of proinflammatory cytokines (IL-1beta, IL-6, TNF-alpha) in human skin wounds

Proinflammatory cytokines play an important role in the mediation of inflammation and trauma. They could be useful for the determination of vitality and wound age. In the present study, 144 human skin wounds due to sharp force were investigated. The material was collected during operations (N=96) and postmortem examinations (N=48). The wound age varied from several seconds or minutes to 9 days. Control skin was available in each individual. The tissue specimens were homogenized and extracted in a solution of PBS and protease inhibitors. Interleukin-1beta (IL-1beta), interleukin-6 (IL-6) and tumour necrosis factor alpha (TNF-alpha) were measured by quantitative ELISA analysis. Statistical evaluation was performed by the t-test using the quotients of levels (wound sample/control skin). In surgical specimens the cytokine levels revealed a clear tendency to increase with wound age. IL-1beta in early skin wounds (</=30 min) and TNF-alpha after a wound age of 1-2 h demonstrated statistically significant changes in comparison with control skin (P<0.05). In autopsy samples with severe traumatization excessive elevation of cytokine levels was observed: IL-1beta, IL-6 and TNF-alpha showed significant increases (P<0.001-0.05) in stab and incised wounds with very short survival times of less than 5 min, but not in possibly supravital injuries. Elevated IL-6 levels persisted in older wounds (>24 h, P<0.05). The quantitative analysis of proinflammatory cytokines in wound extracts can contribute to the determination of vitality and wound age, in particular in the very early post-traumatic interval (classic stab wounds).

Human bone marrow stromal cell: coexpression of markers specific for multiple mesenchymal cell lineages

The role of hematopoietic stem cells in blood cell development is reasonably understood, whereas the identity and the function of bone marrow stromal cells are much less clear. Using stromal cells in bone marrow cultures of the Dexter type, a favorite medium for the study of hematopoiesis, we show that stromal cells actually represent a unique cell type. Conventional wisdom has held that stromal cells in Dexter cultures comprise a mixture of macrophages, hematopoietic cells, adipocytes, osteoblasts, fibroblasts, muscle cells, and endothelial cells. Our findings demonstrate that Dexter cultures consist of three cell types: macrophages ( approximately 35%), hematopoietic cells ( approximately 5%), and nonhematopoietic cells ( approximately 60%). We have purified the nonhematopoietic cells free of macrophages and hematopoietic cells to produce compelling evidence that they in fact represent a single cell type (multidifferentiated mesenchymal progenitor cell, MPC) which coexpresses genes specific for various mesenchymal cell lineages including adipocytes, osteoblasts, fibroblasts, and muscle cells. We further show that these multi- or pluridifferentiated MPCs are capable of supporting hematopoiesis by demonstrating the expression of several hematopoietic growth factors and extracellular matrix receptors including G-CSF, SCF, VCAM-1, ICAM-1, and ALCAM. Since the MPCs can be easily purified to near homogeneity (95%), they can be of value in enhancing engraftment of hematopoietic stem cells. Also, this new understanding of bone marrow stromal cells as "one cell with many different faces" promises to advance our knowledge of regulatory cellular interactions within bone marrow.

Distribution of Th1, Th2, and Th0 and the Th1/Th2 cell ratios in human peripheral and endometrial T cells

PROBLEM

To examine whether normal pregnancy involves type 2 T-helper (Th2) immune condition or not.

METHOD OF STUDY

We measured the percentage of Th0, Th1, and Th2 and the Th1/Th2 cell ratios of human peripheral blood and endometrial T cells using flow cytometry, which can analyze both the surface marker CD3, and intracellular cytokines, interleukin 4 (IL-4) and interferon gamma (IFNgamma).

RESULTS

No significant differences were found in the percentages of Th1, Th2, and Th0 and the Th1/Th2 cell ratios in the peripheral blood T cells of nonpregnant women and women in early pregnancy. On the other hand, the percentage of Th1 cells was highest during the proliferative phase of the endometrium, followed by the secretory phase and early pregnancy decidua. The percentage of Th2 cells was highest in early pregnancy decidua and lowest during the proliferative phase of the endometrium. The Th1/Th2 ratio was 147.48+/-96.68 during the proliferative phase of the endometrium, 37.74+/-21.33 during the secretory phase, and 1.31+/-0.48 in the early pregnancy decidua.

CONCLUSIONS

These data indicate that Th1 cells predominate in the nonpregnant endometrium, especially during the proliferative phase, while Th2 cells predominate in early pregnancy decidua.

Growth-factor-dependent migration of human lung-cancer cells

Human lung tumors express different types of growth-factor receptors and corresponding ligands that might modulate several biological functions such as proliferation, differentiation, adhesion, and chemotaxis. In the present study, we have investigated the expression of different growth-factor receptors and their ligands in 5 established human lung-cancer cell lines. Using RT-PCR, we found that IGF-II/mannose-6-phosphate (M6P), c-met, EGF and c-kit receptors are expressed in 5/5 human lung-cancer cell lines. In order to investigate the biological function of these receptors, we performed Boyden-chamber assays using various growth factors as chemo-attractants. Human non-small-cell-lung-cancer cells (non-SCLC) migrated to recombinant human (rh)IGF I and IGF II at concentrations ranging from 1 to 1000 ng/ml, to HGF at 10 to 100 ng/ml, to EGF at 1 to 100 ng/ml and SCF at 1 to 50 ng/ml. In addition, we performed Boyden-chamber assays using U-1810-, U-1752- and Wart-derived serum-free conditioned medium as chemo-attractants. Serum-free conditioned medium stimulated migration of producer cells in a dose-dependent manner. The autocrine motility stimulating effect of U-1810-derived serum-free conditioned medium could be inhibited by 50% in the presence of neutralizing ahIGF-II antibodies in the assay, suggesting a possible autocrine motility loop in vitro.

Enhancement by stem cell factor of interleukin-2 (IL-2)-induced DNA synthesis in human decidual CD16- CD56bright natural killer cells mediated by increased expression of the IL-2 receptor alpha chain

Extracts of chorionic villous and decidual tissue specimens from women in the early stages of pregnancy contained stem cell factor (SCF), the amount in the latter tissue (246.6+/-119.7 pg/mg protein) being approximately three times that in the former. Immunohistochemical analysis revealed the presence of SCF in the mesenchymal cells of the chorion, the trophoblast, and decidual stromal cells, whereas the SCF receptor, c-kit, was detected in the trophoblast and decidual mononuclear leukocytes but not in decidual stromal cells. Reverse transcription and polymerase chain reaction analysis detected transcripts corresponding to both secretory and membrane-bound types of SCF in chorionic tissue, but only those encoding the secretory type in decidual tissue. Flow cytometric analysis showed that c-kit was expressed on decidual CD16- CD56bright natural killer (NK) cells, CD14+ macrophages, and CD34+ hematopoietic progenitor cells, but not on CD3+ T cells or CD16+ NK cells. Although SCF alone had no effect on DNA synthesis in decidual CD16- CD56bright NK cells, it enhanced the proliferative effect of interleukin-2 (IL-2) at IL-2 concentrations that selectively saturate the high-affinity IL-2 receptor (IL-2R). Flow cytometry of decidual mononuclear leukocytes cultured in the presence of SCF demonstrated that this factor increased the expression of the IL-2Ralpha chain, but not IL-2Rbeta and gamma chain expression on CD16- CD56bright NK cells. Results suggest that SCF produced in the decidua increases the expression of the IL-2Ralpha which is usually present in smaller amounts than other two IL-2R chains on decidual CD16- CD56bright NK cells, and thereby promotes the proliferation of these cells in response to low concentrations of IL-2, resulting in an increase of the high affinity IL-2Rs.

Functional expression on human trophoblasts of interleukin 4 and interleukin 7 receptor complexes with a common gamma chain

The gamma chain in the high-affinity receptor complex for interleukin 2(IL-2) is used in receptor complexes for IL-4 and IL-7. We examined expression and function of the gamma chain in trophoblast cells. Flow cytometric studies demonstrated that the human placental cell line and choriocarcinoma cell lines expressed the IL-2R gamma chain. None of these cell lines expressed the IL-2R alpha and beta chains, whereas the alpha chains of IL-4R and IL-7R were present. The gamma chain and IL-4R and IL-7R mRNA were detected in human placental trophoblasts by the in situ hybridization method. The release of human chorionic gonadotropin by trophoblasts was accelerated by IL-4 and IL-7 in a concentration-dependent manner. These findings indicate that IL-4 and IL-7 are involved in trophoblast function.

Promotion of proliferation of murine hematopoietic stem cells by growth factors in murine amniotic fluid

It has been shown that murine amniotic fluid (MAF) displays immunosuppressive activities. We examined the effect of MAF obtained from normal mice on a murine fetal liver cell (FLC) primary culture in vitro for the detection of the possible existence of cytokines that affect hematopoiesis. MAF promoted proliferation of murine FLC and adult bone marrow cells. Proliferation-promoting activity of MAF was observed throughout the period between days 12 and 15 of pregnancy, peaking at day 12. Pooled MAF was subjected to purification procedures to isolate the active molecule(s). After ion exchange and size exclusion chromatography, one of the active molecules was shown to react with anti-mouse stem cell growth factor (SCF) antibody and the molecular weight was determined as 40-45 kDa by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot. The proliferation-promoting activity of MAF was partially neutralised by the anti-SCF antibody. These results provide evidence that MAF may contain multiple growth factors for FLC, one of which may be a unique molecule related to SCF.