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J R Head

Publications and source records attributed to J R Head.

At least 19 recordsLinked to original sources
PubMed1999

Uterine natural killer cells are targets for a trophoblast cell-specific cytokine, prolactin-like protein A.

PRL-like protein A (PLP-A) is a member of the PRL family expressed in trophoblast cells coincident with establishment of the chorioallantoic placenta. The purpose of this investigation was to identify targets for PLP-A. Using an alkaline phosphatase-tagging strategy, we show that PLP-A specifically interacts with a population of natural killer (NK) lymphocytes within the mesometrial compartment of decidua from pregnant and pseudopregnant rats. These observations are supported by the codistribution of PLP-A targets with cells expressing the rat NK cell surface marker, gp42, the absence of PLP-A binding in conceptuses from NK cell-deficient tg epsilon26 mice, and the specific interaction of PLP-A with a rat NK cell line, RNK-16. We have further demonstrated that PLP-A effectively suppresses RNK-16 cell cytolytic activities. Our results provide evidence for a new paradigm of embryonic-maternal communication involving a PLP-A signaling pathway between trophoblast cells and uterine NK lymphocytes.

Alkaline Phosphatase↗
PubMed1998

Thrombospondin-1 expression in human myometrium before and during pregnancy, before and during labor, and in human myometrial cells in culture.

The activation of latent transforming growth factor beta (L-TGFbeta) is essential for the action of TGFbeta, which, in turn, is involved in the regulation of expression of some progesterone-responsive genes. One mechanism by which TGFbeta is activated involves thrombospondin (TSP), a protein that binds extracellular proteins. Immunoreactive TSP (irTSP) protein and TSP-1 mRNA in myometrial tissues of ovulatory and pregnant women were localized by immunohistochemistry and in situ hybridization. IrTSP and TSP-1 mRNA were randomly distributed in myometrial smooth muscle cells of some, but not all, tissues of pregnant women at term before labor; but in some areas of most of these tissues, irTSP was intense and commonly localized extracellularly. Intense irTSP and TSP-1 mRNA in myocytes were more common in myometrium during labor. In myometrium from ovulatory women (n = 26), irTSP was localized primarily in vascular smooth muscle cells and was detected occasionally in scattered myocytes. Little TSP-1 mRNA was demonstrable by in situ hybridization in vessels or myocytes of myometrial tissue from ovulatory women (n = 7). By Northern analysis of total RNA, TSP-1 mRNA was detected in myometrial tissue of pregnant women and in human myometrial smooth muscle cells in culture. The levels of TSP-1 mRNA in myometrial tissues of pregnant women during labor (n = 18) were greater than those in myometrium at > 37 wk gestation before labor began (n = 25, p < 0.001). The ratios of TSP-1 to glyceraldehyde 3-phosphate dehydrogenase mRNAs in 3 myometrial tissues during oxytocin-induced labor were not statistically different from those in myometrium during spontaneous labor but were greater than those in myometrium before labor (p < 0.05). The level of TSP-1 mRNA in confluent human myometrial cells in culture was relatively high, was increased by treatment with fetal bovine serum, and was decreased by treatment with platelet-derived growth factor or activators of adenylyl cyclase or protein kinase C. Myometrial cells in culture constitute a useful model for studying the regulation of TSP-1 gene expression in human myometrium.

Adult↗
PubMed1998

Characterization of cDNAs encoding isoforms of hamster 3 beta-hydroxysteroid dehydrogenase/delta 5-->4 isomerase.

Western blot analyses of various hamster tissues reveal high levels of expression of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) in adrenal and liver, and moderate levels of expression in kidney. The expression in liver is sexually dimorphic; very high levels of protein are observed in adult male liver but very low levels are seen in the female liver. Three distinct cDNAs encoding isoforms of 3 beta-HSD were isolated from hamster cDNA libraries. The type 1 isoform is a high-affinity dehydrogenase/isomerase expressed in adrenal and male kidney. The type 2 isoform is also a high-affinity dehydrogenase/isomerase expressed in kidney and male liver. The type 3 enzyme is a 3-ketosteroid reductase expressed predominantly in kidney. Sequencing of the clones showed that all three are structurally very similar, although types 1 and 2 share the greatest degree of similarity. Immunohistochemical staining for 3 beta-HSD in the adrenal was found throughout the adrenal cortex. In the kidney staining was confined to tubules, and in the liver, heavy staining was found in hepatocytes. The cloning of cDNAs for 3 beta-HSD from the liver and kidney should help in elucidating the function of this enzyme in these tissues.

Adrenal Glands↗
PubMed1997

Cell type-specific expression of 17 beta-hydroxysteroid dehydrogenase type 2 in human placenta and fetal liver.

The enzymatic actions of the 17 beta-hydroxysteroid dehydrogenase (17 beta HSD) isozymes are crucial in steroid hormone metabolism/physiology. The type 1 isozyme catalyzes the conversion of the biologically inactive C18 steroid, estrone, to the active estrogen, 17 beta-estradiol, and the enzyme is predominantly expressed in the syncytiotrophoblast of the placenta and the granulosa cells of the ovary. 17 beta HSD type 2 is highly expressed in placenta, liver, and secretory endometrium and catalyzes the conversion of bioactive estrogens and androgens to biologically inactive 17-ketosteroid counterparts. The expression pattern of 17 beta HSD type 2 protein was determined in human term placenta and fetal liver by immunohistochemical analysis using monoclonal antibodies directed against distinct epitopes of the 17 beta HSD type 2 protein. In placenta, the protein was detected in the endothelial cells of fetal capillaries, but not in cytotrophoblasts or syncytiotrophoblast. There was dichotomous immunostaining seen among pairs of cotyledonary vessels and chorionic vessels. In the liver, on the other hand, staining was detected in the hepatocytes, but not in the cells lining blood vessels. We conclude that the cell type-specific localization of 17 beta HSD type 2 is in accord with the proposed physiological role of the enzyme, namely to protect tissues, in this case the fetus, from bioactive estrogen and androgen.

17-Hydroxysteroid Dehydrogenases↗
PubMed1994

GM-CSF and CSF-1 stimulate DNA synthesis but not cell proliferation in short-term cultures of mid-gestation murine trophoblast.

Short-term cultures of purified murine trophoblast were used to investigate the potential trophic effects of a number of cytokines. Both granulocyte-macrophage colony stimulating factor (GM-CSF) and colony stimulating factor-1 (CSF-1) increased [3H]thymidine (TdR) uptake (3-8 times control values) by trophoblast harvested from placentae on day 12 or 14 of pregnancy. In contrast, interleukin-3 (IL-3) had only a mild stimulatory effect ([3H]TdR uptake 1.5 times control), and IL-2 did not alter the level of DNA synthesis in these cells. Immunocytochemical analysis confirmed that the cells engaged in DNA synthesis were cytokeratin-positive trophoblast cells and revealed that these cells predominantly bore markers (alkaline phosphatase, transferrin receptors) characteristic of trophoblast cells from the placental labyrinth. The increased DNA synthesis observed after exposure to GM-CSF or CSF-1 was not associated with a change in the proportion of nuclei involved in synthesis, nor did it result in significantly increased trophoblast cell numbers in the cultures. These findings suggest that DNA-synthesizing trophoblast cells were not proliferating, but were more likely engaged in endoreduplicative cycles leading to the formation of terminally differentiated trophoblast giant cells. These results caution against the presumption of proliferation when measuring [3H]thymidine incorporation by placental or trophoblast cells in standard in vitro cultures. In addition, taken together with the reports of high levels of CSF-1 in the pregnant uterus and the expression of the CSF-1 receptor on placental trophoblast cells, they suggest that the hemopoietic cytokines may play a role in the differentiation and/or function of trophoblast cells in the developing murine placenta.

Animals↗
PubMed1994

Tenascin in pregnant and non-pregnant rat uterus: unique spatio-temporal expression during decidualization.

Tenascin is a large extracellular matrix (ECM) protein generally restricted to developing embryonic tissues and tissues undergoing remodelling in the adult, but it has been suggested that tenascin is immunomodulatory. In this study we have used indirect immunofluorescence to investigate the distribution of tenascin within the uteri of pregnant and non-pregnant rats. The non-pregnant uterus expressed tenascin in the stroma around the glands, but only the subluminal stroma showed cyclical variations. Dependence of the latter on progesterone was verified in ovariectomized animals supplemented with steroid hormones. During early pregnancy, the uterine circular smooth muscle maintained an intense expression of tenascin. In the decidualizing endometrium, tenascin expression showed dramatic changes that reflected the regionalization of the decidualization process. On Day 6 (blastocyst attachment), tenascin immunoreactivity was prominent in the primary decidualization zone immediately surrounding the conceptus. On Day 7, expression had increased within the secondary decidua that had developed throughout the antimesometrial endometrium. By Day 8, the antimesometrial decidua showed diminished tenascin immunoreactivity; expression became largely confined to the ECM of the developing decidua in the mesometrial region, where levels were high. On Day 10, the well-developed mesometrial decidua was negative. Interestingly, tenascin expression was up-regulated in the walls of the vessels in the metrial gland within the mesometrial triangle beginning on Day 10 of pregnancy. From these studies we conclude that tenascin expression may be an important reflection of the dynamics involved with tissue restructuring during early pregnancy and may play a role in immunomodulation, since expression of this protein in the mesometrial decidua coincides with the presence of differentiating natural killer cell lineage lymphocytes in the same region.

Animals↗
PubMed1994

NKR-P1+ cells in the rat uterus: granulated metrial gland cells are of the natural killer cell lineage.

An intriguing component of the maternal response to pregnancy is the differentiation of large numbers of large granular lymphocytes, termed granulated metrial gland (GMG) cells, in the decidua and then in the metrial gland, a structure in the mesometrial triangle unique to rodent pregnancy. We have used the monoclonal antibody 3.2.3 to NKR-P1, a surface molecule involved in triggering natural killer (NK) cells for lysis, to determine the numbers and distribution of NK cells in the nonpregnant rat uterus and during the dramatic changes at implant sites during pregnancy. NKR-P1+ cells were abundant in the nonpregnant uterus, especially in the endometrium. These cells also expressed CD8, CD2, and AsialoGM1. In the subepithelial stroma, the numbers were greatest during proestrus and estrus; in ovariectomized animals, they were severely decreased, but returned to normal with estrogen supplementation. At the time of blastocyst attachment (Day 6), NKR-P1+ cells were few around the implant and in the decidualizing stroma. However, on Day 8, substantial numbers were present in the mesometrial decidua only, and many of these cells expressed the cytolytic protein perforin. By Day 10, NKR-P1+ cells were common within the inner muscle at the base of the mesometrial triangle and in the developing metrial gland, often containing perforin. Larger numbers of perforin+ cells were present in the central decidua towards the ectoplacental cone, and many were weakly NKR-P1+ only. On Day 12, NKR-P1+ cells were almost completely restricted to the metrial gland, with few in decidua, and many were weakly positive. Substantially more perforin-containing cells were seen, indicating that many had lost detectable NKR-P1. This distribution pattern from Days 6-12 is similar to that described for GMG cells and demonstrates that in the rat they belong to the NK cell lineage. These cells were also CD8+ and AsialoGM1+ but negative for CD2 and class II histocompatibility antigens, which is very different from interleukin-2-activated NK cells which they resemble morphologically. The loss during differentiation of NKR-P1 and CD2, which are involved in target adhesion and triggering of NK cells, is consistent with the poor cytolytic capacity reported for these cells.

Animals↗
PubMed1993

Regulation of interleukin-8 gene expression in human endometrial cells in culture.

In this study, we investigated the regulation of interleukin-8 (IL-8) gene expression in separated endometrial stromal and epithelial cells of human endometrium. This research was conducted as part of an analysis of the role of these cells in regulating the recruitment of leukocytes to the endometrium. Well-characterized model systems were used to study the regulation of endometrial IL-8 gene expression, namely, stromal cells in monolayer culture after first passage and glandular epithelium in primary culture. The levels of IL-8 mRNA and the accumulation of immunoreactive IL-8 in the medium of endometrial stromal cells is culture increased in a time- and concentration-dependent manner upon treatment with IL-1 alpha, tumor necrosis factor-alpha, or serum. The effects of IL-1 alpha plus serum on IL-8 mRNA levels were at least additive. Serum treatment caused a modest stimulation of IL-8 gene transcription (evaluated after 6 h of treatment) in endometrial stromal cells, but serum also acted in these stromal cells to prolong the half-life of IL-8 mRNA by more than 2.5-fold. The regulation of the levels of IL-8 mRNA in endometrial epithelial cells is distinctly different from that in stroma. First, the levels of IL-8 mRNA in non-treated epithelial cells in serum-free medium were much greater than those in stromal cells under similar conditions. Second, whereas the levels of IL-8 mRNA in endometrial epithelial cells also increased in response to serum and to IL-1 in the absence of serum, in the presence of serum, IL-1 treatment caused no appreciable change in the levels of IL-8 mRNA as was the case in endometrial stromal cells.

Base Sequence↗
PubMed1993

Regulation of expression of the 3 beta-hydroxysteroid dehydrogenases of human placenta and fetal adrenal.

The appropriate expression of 3 beta-hydroxysteroid dehydrogenase/delta 5-->4-isomerase (3 beta-HSD) is vital for mammalian reproduction, fetal growth and life maintenance. Several isoforms of 3 beta-HSD, the products of separate genes, have been identified in various species including man. Current investigations are targeted toward defining the processes that regulate the levels of specific isoforms in various steroidogenic tissues of man. High levels of expression of 3 beta-HSD were observed in placental tissues. It has been generally considered that the multinucleated syncytiotrophoblastic cells are the principal sites of 3 beta-HSD expression and, moreover, that 3 beta-HSD expression is intimately associated with cyclic AMP-promoted formation of syncytia. Herein we report the presence of 3 beta-HSD immunoreactive and mRNA species in uninucleate cytotrophoblasts in the chorion laeve, similar to that in syncytia but not cytotrophoblast placenta. In vitro, 3 beta-HSD levels in chorion laeve cytotrophoblasts were not increased with time nor after treatment with adenylate cyclase activators, whereas villous cytotrophoblasts spontaneously demonstrated progressive, increased 3 beta-HSD expression. Moreover, 3 beta-HSD synthesis appeared to precede morphologic syncytial formation. Thus high steroidogenic enzyme expression in placenta is not necessarily closely linked to formation of syncytia. Both Western immunoblot and enzymic activity analyses also indicated that the 3 beta-HSD expressed in these cytotrophoblastic populations was the 3 beta-HSD type I gene product (M(r), 45K) and not 3 beta-HSD type II (M(r), 44K) expressed in fetal testis. In cultures of fetal zone and definitive zone cell of human fetal adrenal, 3 beta-HSD expression was not detected until ACTH was added. ACTH, likely acting in a cyclic AMP-dependent process, induced 3 beta-HSD type II activity and mRNA expression. The higher level of 3 beta-HSD mRNA in definitive zone compared with fetal zone cells was associated with parallel increases in cortisol secretion relative to dehydroepiandrosterone sulfate formation.

3-Hydroxysteroid Dehydrogenases↗
PubMed1993

Cellular localization of membrane metalloendopeptidase (enkephalinase) in human endometrium during the ovarian cycle.

Previously, we found that membrane metalloendopeptidase (MMEP; enkephalinase) is present in human endometrium where it may inactivate certain bioactive peptides such as endothelin. The specific activity of MMEP in endometrium is correlated positively with the level of plasma progesterone. In the present study, we determined the cellular distribution of MMEP immunoreactivity (IR) in samples of endometrium from 31 ovulatory women at different phases of the menstrual cycle and from 5 postmenopausal women. At all times, MMEP-IR was localized in the endometrial stromal cells and was absent from myometrium, epithelia, and vessels. The presence of the enzyme on the stromal cell plasma membrane was demonstrated by immunostaining of freshly isolated endometrial stromal cells. During the endometrial cycle, there were dramatic changes in MMEP-IR in the zona functionalis: In the proliferative phase when plasma progesterone levels were low, MMEP-IR was weak; but after ovulation, during the early and midsecretory phases, when progesterone levels were increasing or high, MMEP-IR was strong. During the late secretory phase, in the stromal areas that were decidualized, contiguous with spiral arterioles and beneath the surface epithelium, most of the MMEP-IR was lost, whereas MMEP in the other stromal areas remained strong. In the premenstrual phase, there was a more generalized decline in MMEP-IR in the stromal cells. MMEP-IR in the zona basalis was weak to moderate and was relatively unchanged during the ovarian cycle; the findings in postmenopausal tissues were similar to those of proliferative phase tissues. These results are consistent with the previous findings of increased MMEP mRNA, protein, and activity in endometrial tissue of midsecretory phase and in cultured endometrial stromal cells in response to progestin. Furthermore, in this study, we demonstrate that in the late secretory phase in decidualizing stroma, MMEP-IR is decreased considerably compared with midsecretory stromal cells. These changes in MMEP-IR are consistent with the possibility that endothelin, also produced in endometrium, is spared inactivation in the premenstrual phase and may act on the spiral arterioles. These findings are supportive of a role for MMEP in paracrine interactions affecting vascular homeostasis in the endometrium.

Endometrium↗
PubMed1992

Culture characteristics of human endometrial glandular epithelium throughout the menstrual cycle: modulation of deoxyribonucleic acid synthesis by 17 beta-estradiol and medroxyprogesterone acetate.

OBJECTIVE: The purpose of this study was to evaluate the culture characteristics and cell proliferation of human endometrial glandular epithelial cells in primary culture on extracellular matrix and to evaluate sex steroid modulation of this process. STUDY DESIGN: We examined the culture characteristics in 53 endometrial gland preparations obtained throughout the menstrual cycle and determined the incorporation of tritiated thymidine in endometrial epithelial cells as a measure of deoxyribonucleic acid synthesis (cell proliferation) in the presence and absence of 17 beta-estradiol and medroxyprogesterone acetate. RESULTS: Good culture maintenance of endometrial epithelial monolayers on extracellular matrix was observed from glands derived from proliferate phase endometrium (21 of 23), whereas poor adherence and culture maintenance was observed in all 30 of specimens from the secretory phase. With 17 beta-estradiol treatment for 22 hours, tritiated thymidine incorporation was not different from control, but medroxyprogesterone acetate treatment for 22 hours was associated with diminished tritiated thymidine incorporation by 36% (p < 0.004). When 17 beta-estradiol (10(-8) mol/L) was included in the incubation medium from the time of initial culture, tritiated thymidine incorporation on day 4 was 40% of control (p < 0.006), and tritiated thymidine was not suppressed further by 22 hours of treatment with medroxyprogesterone acetate (10(-7) mol/L). In spite of cellular spread of endometrial epithelial cells to subconfluence, deoxyribonucleic acid content per well did not increase over time in culture. CONCLUSIONS: We conclude that exposure of endometrial glands to progesterone in vivo inhibits adherence and the establishment of cell monolayers cultured on a thin layer of extracellular matrix. Because 17 beta-estradiol treatment in culture for 22 hours does not increase tritiated thymidine incorporation, it is possible that 17 beta-estradiol exerts its proliferative effect on the endometrial epithelium by an indirect action mediated by stromal cells. The effects of 17 beta-estradiol and medroxyprogesterone acetate on deoxyribonucleic acid synthesis in endometrial epithelial cells may represent an action on a stem cell population of dividing cells or a terminally differentiated cell population that undergoes programmed cell death.

Cells, Cultured↗
PubMed1992

Expression of steroidogenic enzymes in the bovine placenta and fetal adrenal glands throughout gestation.

The expression of cholesterol side-chain cleavage cytochrome P450 (P450scc), 17 alpha-hydroxylase cytochrome P450 (P45017 alpha), and 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) was studied in bovine placenta and fetal adrenal glands throughout gestation. The levels of expression of these enzymes were much lower in the placenta than in the adrenals by Western and Northern analyses. The levels of P450scc, however, remained relatively constant in bovine placenta and fetal adrenal glands at all gestational stages studied. In contrast, P45017 alpha expression was higher in both the placenta and the fetal adrenal glands during the early stages of pregnancy, but declined markedly in both tissues through the period of midgestation. The expression of P45017 alpha increased markedly in the fetal adrenal glands in late gestation. The levels of 3 beta HSD were extremely low in placental tissues, but were higher in the fetal adrenals, where they were found to be slightly elevated in early and late gestation compared to those in midgestational stages. Immunocytochemical examination of the levels of P45017 alpha and 3 beta HSD in the fetal adrenal glands correlated with the results of Western and Northern analyses. In addition, the morphology and distribution of these two enzymes in the developing bovine fetal adrenal glands indicated that while the early activated gland is functional relative to the ability to secrete steroids, structural and functional organization more typical of mature adrenal glands is not achieved until the time of activation of the fetal adrenals in late gestation.

3-Hydroxysteroid Dehydrogenases↗
PubMed1991

Regulation of expression of male-specific rat liver microsomal 3 beta-hydroxysteroid dehydrogenase.

In the steroidogenic pathways present in the gonads and adrenal cortex, 3 beta-hydroxysteroid dehydrogenase isomerase (3 beta HSD) is a key enzyme which controls the formation of delta 4-3-ketosteroids from delta 5-3 beta-hydroxysteroids. Herein, we used an antibody against human placental 3 beta HSD and a rat testicular 3 beta HSD cDNA probe to study the expression of rat liver 3 beta HSD mRNA and protein. Rat liver microsomal 3 beta HSD activity has been previously reported to exhibit a significant sex difference, with much higher activity in the male. We have shown an age-dependent increase in levels of immunoreactive 3 beta HSD through the time of maturation of the male rat. The immunoreactive protein, of similar molecular size to the human placental and rat testicular 3 beta HSD, was localized to the microsomal fraction of liver and was concentrated in pericentral locations. Immunoreactive protein was not detected in liver of immature (before 25 days of age) rats of either sex or in adult female liver. Northern blot analysis of liver and testicular RNA with a rat testicular 3 beta HSD cDNA probe revealed the presence of a 1.6-kilobase mRNA species in addition to the major 2.1-kilobase mRNA species in adult male liver, neither of which was detected in immature or adult female liver RNA. Hypophysectomy of female rats or treatment with testosterone implants caused induction of liver 3 beta HSD protein, while continuous infusion of GH to male rats decreased the level of 3 beta HSD protein. Similarly, the levels of the mRNA species were decreased after GH treatment. Using [3 alpha-3H]dehydroepiandrosterone as substrate for 3 beta HSD activity, we determined the apparent Km for liver microsomal NAD(+)-dependent 3 beta HSD activity to be 20 microM in both adult male and female liver and was much greater than the Km of rat Leydig tumor 3 beta HSD activity (0.2 microM). Liver 3 beta HSD activity was inhibited by trilostane, a proven inhibitor of gonadal and adrenal 3 beta HSD activity. A rat liver 3 beta HSD cDNA was isolated from a male liver cDNA library that was closely related to the type II 3 beta HSD form of rat ovary but different from type III liver 3 beta HSD. The enzyme obtained upon expression of this cDNA had properties characteristic of male-specific NAD(+)-dependent liver microsomal 3 beta HSD (i.e. high apparent Km for dehydroepiandrosterone) and distinct from those of the high affinity gonadal type I 3 beta HSD.(ABSTRACT TRUNCATED AT 400 WORDS)

3-Hydroxysteroid Dehydrogenases↗
PubMed1990

Decidua-associated suppressor activity and viability of individual implantation sites of allopregnant C3H mice.

Release of soluble suppressor activity from individual implant site decidua of DBA/2-mated C3H/HeJ mice was measured on days 12.5-13.5 of pregnancy. Suppressor activity varied among sites and followed a distribution curve that was displaced towards low suppression when resorption sites were compared to healthy embryonic implants. Pre-immunization against the DBA/2 strain paternal antigens failed to increase resorption (by loss of low suppression implants) but led instead to a reduced resorption rate. This was associated with an increase in soluble suppressor activity obtained from decidua. Some reduction in resorption occurred independent of an increase in the level of suppression suggesting additional contributing factors to the immunization effect.

Animals↗
PubMed1990

Murine trophoblast cells are not killed by tumor necrosis factor-alpha.

Purified midgestation murine trophoblast cannot be killed by a variety of cell-mediated effector mechanisms, with the exception of highly lytic effectors such as lymphokine-activated killer cells. We now report that this trophoblast population is also resistant to tumor necrosis factor (TNF)-alpha.

Analysis of Variance↗