NF-κB-associated mechanisms underlying the response of embryonic cells to Doxorubicin.

The involvement of NF-κB in the regulation of teratogen-induced apoptosis has not been established yet. Therefore, we tried to assess the involvement of the p65 subunit of NF-κB in the embryonic response to the anti-cancer drug Doxorubicin (DOX). Thus, exposure of p65 knockout (p65(-/-)) or wild type (WT) mouse embryonic fibroblasts (MEFs) to DOX resulted in a decrease in cell survival, culture density and cell proliferation, which was found to be more prominent in p65(-/-) MEFs. Those phenomena were accompanied by a DOX-induced increase in the proportion of apoptotic cells, which was demonstrated only in p65(-/-) cells and a G2/M arrest, which was found to be more prominent in WT cells. Furthermore, DOX-treated WT and p65(-/-) MEFs differed in their expression of various apoptosis-associated molecules, when the former demonstrated a decrease in the percentage of p65-positive and a more prominent decrease in the percentage of p53-positive cells, while a decreased percentage of IκBα-positive and a more prominent decrease in the percentage of bcl-2-positive cells was detected among the latter. The fact that the response of the cells to the teratogen was clearly p65-dependent implicates this molecule to be involved in the response of the embryonic cells to DOX.

Bax-associated mechanisms underlying the response of embryonic cells to methotrexate.

Bax was shown previously to regulate apoptotic cell death in various experimental systems, however, its involvement in teratogen-induced apoptosis is not clear yet. Therefore, we explored the involvement of Bax in the response of mouse embryonic fibroblasts (MEFs) to the anti cancer drug methotrexate (MTX), using Bax wild type (WT) and knockout (Bax(-/-)) MEFs. Our results demonstrated a significant teratogen-induced dose- and time-dependant decrease in the survival and culture density of both cell lines, which were found to be somewhat more prominent in WT cells. Exposure to MTX resulted also in decreased cell proliferation of WT but not Bax(-/-) cells and accordingly, we observed an accumulation of cells in the S phase and an increased percentage of cells in the Sub-G(1) phase of the cell cycle and the appearance of condensed nuclei, which were found to be somewhat more prominent in WT MEFs. In parallel, WT MEFs demonstrated a MTX-induced increase in the percentage of Bax-positive cells and a significant decrease in the percentage of bcl-2-, p65- or IkappaBalpha-positive cells, which were not detected in Bax(-/-) MEFs. Altogether, the differential sensitivity of WT or Bax(-/-) MEFs to MTX suggests a possible involvement of this molecule in the response of embryonic cells to teratogens.

NF-kappaB regulates the response of embryonic cells to heat shock.

NF-kappaB was shown previously to regulate apoptotic cell death processes in various experimental systems. However, its role in controlling teratogen-induced cell death has not been established yet. Therefore, the objective of the present study was to explore the involvement of the p65 subunit of NF-kappaB in the response of mouse embryonic fibroblasts (MEFs) to heat shock, using p65 knockout (p65-/-) cells. Indeed, we found p65-/- MEFs to be more susceptible to the exposure to heat shock, as compared with wild-type (WT) MEFs, as they demonstrated a more prominent decrease in cell survival and proliferation as well as the appearance of cells undergoing apoptotic cell death. These heat-shock-induced effects were preceded by a decrease in p65 expression in WT cells, which was accompanied by a decrease in IkappaBalpha expression in WT MEFs, while disappearing completely in p65-/- MEFs and accordingly, by an increase in p-IkappaBalpha expression in both cell lines, which was found to be more prominent in p65-/- MEFs. Interestingly, the heat shock-induced decrease in p65 expression was accompanied by an increase in HSP70 expression in both cell lines. However, it was again found to be more prominent in p65-/- MEFs. Taken together, our results suggest a protective role for the p65 subunit of NF-kappaB in mechanisms underlying the response of embryonic cells to heat shock.

Diabetes teratogenicity is accompanied by alterations in macrophages and T cell subpopulations in the uterus and lymphoid organs.

Insulin-dependent diabetes mellitus is a well-known teratogen, which might cause growth retardation, malformations and fetal death. We have previously shown, that potentiation of the maternal immune system (immunopotentiation) might protect the embryo from diabetes teratogenicity. Therefore, in the present study we further inquired whether diabetes teratogenicity might be associated with alterations in the level of immune effector cells in systemic and local lymphoid organs as well as in the uterus throughout pregnancy and whether the protection exerted by maternal immunopotentiation might be realized through its effect on those cells. Streptozotocin-induced diabetes in ICR mice was found to reduce pregnancy rate and fetal weight while increasing the resorption rate and the percentage of litters with malformed fetuses. These teratogenic effects were accompanied by a decreased percentage of cells expressing Mac-1, Thy-1.2, CD4 or CD8 in the spleen and inguinal as well as paraaortic lymph nodes, except for Mac-1 expression by splenocytes, which increased significantly in the beginning of pregnancy and decreased later. A different pattern was observed in the uterus, when the percentage of cells expressing these markers tended to increase in the beginning of pregnancy and decrease later. Intrauterine immunopotentiation with rat splenocytes was found to improve the reproductive performance of diabetic animals. This protective effect was accompanied by a general normalization of the level of the various cell surface markers, when in most cases their expression returned to that found in nonimmunopotentiated mice. Our results suggest that the protection exerted by maternal immunopotentiation on the embryo against diabetes teratogenicity might be mediated via its effect on the level of immune effector cells localized to uterus and lymphoid organs, which was found to be altered in diabetic mice.

TNF-alpha acts to prevent occurrence of malformed fetuses in diabetic mice.

AIMS/HYPOTHESIS: Activation of apoptosis in embryos is thought to be a key event in the pathogenesis of diabetes-induced embryopathies such as early embryonic death and inborn structural anomalies. TNF-alpha can activate apoptotic and anti-apoptotic signalling cascades, indicating its ability to contribute to and counteract diabetes-induced maldevelopment. To investigate how TNF-alpha regulates the response of embryos to diabetes-induced embryopathic stress, we used streptozotocin-induced diabetic TNF-alpha knockout mice. MATERIALS: To evaluate the reproductive performance, mated diabetic female mice were examined on days 4 and 8 of pregnancy for the presence of blastocysts or embryos in uterine horns. To evaluate the teratogenic effect, the female mice were killed on day 18 of pregnancy and fetuses were examined for gross external anomalies. In addition, apoptotic nuclei were localised by the TUNEL assay and DNA-binding activity of the transcription factor NF-kappaB was evaluated by electrophoretic mobility shift assay in 10- and 11-day-old embryos respectively. RESULTS: Severely diabetic TNF-alpha(+/+) female mice had a much greater decrease in pregnancy rate but a lower incidence of malformed fetuses in litters than severely diabetic TNF-alpha(-/-) female mice. Also, the intensity of excessive apoptosis was higher, but the amount of active NF-kappaB complexes was lower in malformed TNF-alpha(-/-) embryos than in TNF-alpha(+/+) embryos. CONCLUSIONS/INTERPRETATION: TNF-alpha contributes to death of peri-implantation embryos and possibly protects postimplantation embryos exposed to diabetes-induced teratogenic stimuli via activation of NF-kappaB-mediated anti-apoptotic signalling. It seems that TNF-alpha prevents the birth of malformed offspring in severely diabetic mice.

Increased TNF-alpha expression in cultured mouse embryos exposed to teratogenic concentrations of glucose.

Diabetes-induced early embryonic death is accompanied by an increased expression of tumour necrosis factor alpha (TNF-alpha) in the embryonic microenvironment. The aim of the present study was to evaluate whether diabetes-induced embryopathic stress may also alter the expression of TNF-alpha produced by the embryo itself. As a model, whole postimplantation embryos were cultured for 24 h in a medium with high concentrations of glucose, one of the main diabetes-associated teratogenic metabolites. An anomaly such as an open neural tube was used as an end-point characterizing the glucose-induced teratogenic effect and the number of somites was counted to evaluate growth retardation induced by glucose. The expression of TNF-alpha (by immunohistochemistry), apoptosis (by TdT-mediated dUTP nick-end labelling; TUNEL) and the activity of caspases 3 and 8 (by a fluorometric assay) were evaluated in normal and malformed embryos. Ninety-seven per cent of the embryos exposed to 1300 mg glucose dl(-1) exhibited an open neural tube. The percentage of malformed embryos was smaller in media containing 800 and 500 mg glucose dl(-1) (68 and 37%, respectively) but it still exceeded significantly the value registered in embryos developing in a normoglycaemic medium (12%). In addition, a significant decrease in the number of somites was observed in embryos developing in media containing 1300 and 800 mg glucose dl(-1). Malformed embryos exhibited a greater number of nuclei that were positive in the TUNEL assay as well as a higher amount of active caspase 8 compared with normal embryos (with closed neural folds). TNF-alpha expression was detected in the neuroepithelial layer of the neural tube of the malformed embryos, whereas the expression of this cytokine was weak, if detectable, in normal embryos. Together, these findings indicate that TNF-alpha produced by the embryo may be involved in regulating the response of embryos to diabetes-generated embryopathic stress.

Cytokine expression in the uterus of mice with pregnancy loss: effect of maternal immunopotentiation with GM-CSF.

It is believed that failure of the maternal immune system to actively support embryonic development, through production of the appropriate cytokine network, might be responsible for embryonic death. Thus, the aim of this study was to evaluate the possible involvement of cytokines such as tumour necrosis factor alpha (TNF-alpha) and transforming growth factor beta2 (TGF-beta2), which are crucial for normal embryonic development, in the early stages of mechanisms that mediate induced pregnancy loss. The early stages of the resorption process induced by lipopolysaccharide (LPS) were characterized by blood accumulation in the vicinity of the embryo, preceding any visible embryonic damage. At that time, immunohistochemical analysis revealed an increased expression of TNF-alpha in the primary and secondary decidua, which was reduced as the resorption process was completed. In contrast, TGF-beta2 expression was decreased in the primary and secondary decidua, as well as in the glandular epithelium, at all the times assessed. Maternal immunopotentiation with granulocyte macrophage-colony stimulating factor (GM-CSF), which controls maternal immune activities supporting normal embryonic development, decreased the resorption rate in LPS-treated mice while normalizing the expression of TNF-alpha and TGF-beta2 in the uterus of these animals throughout the ongoing resorption process. These results indicate a possible role for maternal immunopotentiation with GM-CSF in the mechanisms mediating the early stages of pregnancy loss, possibly via modulation of TNF-alpha and TGF-beta2 activity.

Apoptosis in the uterus of mice with pregnancy loss.

PROBLEM: The mechanisms mediating pregnancy loss induced by various agents are far from being understood. Thus, we investigated the possible involvement of one such mechanism, the apoptotic process, in pregnancy loss induced by lipopolysaccharide (LPS) or cyclophosphamide (CP) as well as the associated changes in the apoptosis-regulating gene products p53 and bcl-2. METHOD OF STUDY: Pregnancy loss was induced by LPS or CP on days 9 or 12 of pregnancy, respectively. LPS- or CP-associated apoptosis was assessed by the TdT mediated dUTP-biotin nick end labeling (TUNEL) method as well as by DNA fragmentation analysis, while p53 or bcl-2 expression was evaluated by immunohistochemistry. RESULTS: Lipopolysaccharide treatment initiated a resorption process that was accompanied by the appearance of apoptotic cells in the uterus, which increased in number by 24 hr after treatment. Induction of pregnancy loss with CP resulted in the appearance of some apoptotic cells in the uterus, reaching a peak at 72 hr after treatment. DNA fragmentation analysis revealed a DNA ladder at 24 hr after LPS as well as 72 hr after CP treatment. Immunohistochemical analysis demonstrated a continuous p53 expression in the uterus of LPS- or CP-treated mice, which was somewhat elevated at the peak of the apoptotic process. On the other hand, bcl-2 expression in LPS-treated mice could be reciprocally correlated with the apoptotic process, appearing only at its initiation or completion, while in CP-treated mice it was continuously expressed except for some elevation at the completion of the apoptotic process. CONCLUSIONS: Our results suggest a possible role for the apoptotic process in mechanisms mediating pregnancy loss and indicate an involvement of p53 and bcl-2 in its regulation.

Diabetes teratogenicity in mice is accompanied with distorted expression of TGF-beta2 in the uterus.

Early embryonic deaths as well as malformed newborns are among complications of the diabetic pregnancy. Cytokines and growth factors operating in the embryonic vicinity are found to be among factors that determine the sensitivity of embryos to external and internal detrimental stimuli, including diabetes. Transforming Growth Factor-beta2 (TGF-beta2) has been shown to be essential for embryonic development and survival. In the present work, we evaluated the pattern of TGF-beta2 expression in the uterus of streptozotocin-induced diabetic mice, demonstrating a decreased reproductive performance and elevated percentage of litters with severely malformed fetuses. Since stimulation of the maternal immune system was found to increase the resistance of mouse embryos to the teratogenic effect of diabetes, the effect of immunopotentiation on the expression of the cytokine was also investigated. TGF-beta2 expression was studied at the mRNA level by using the in situ hybridization technique and at the protein level by using the immunohistochemical analysis. A clear decrease in TGF-beta2 mRNA expression in the uterus of diabetic mice was observed at examined time points: days 1, 5, and 9 of pregnancy. Also, an evident reduction in TGF-beta2, the protein expression in the uterus of diabetic mice, was demonstrated at these time points. Maternal immunopotentiation that improved the reproductive performance of diabetic mice and reduced the number of the litters with malformed fetuses was also accompanied by a clear increase in the level of TGF-beta2 mRNA expression in the pregnant uteri. The above results clearly demonstrate that the embryotoxic effect of diabetes is accompanied by an alteration of TGF-beta2 expression. Immunopotentiation that was shown to improve the reproductive performance of the diabetic mice was accompanied by a partial normalization of TGF-beta2 expression in embryonic vicinity.

Expression of tumor necrosis factor-alpha in the pregnant uterus of diabetic mice: effect of maternal immunopotentiation.

PROBLEM: Tumor necrosis factor (TNF)-alpha mRNA and protein are expressed in the pregnant uterus of streptozotocin-induced diabetic mice at various stages of pregnancy. We intend to characterize their pattern and to evaluate whether the potentiation of the maternal immune system alters the pattern of the expression of the cytokine. METHOD OF STUDY: Diabetes was induced in ICR mice by streptozotocin injection. To modulate maternal immune responses, ICR mice were injected intrauterine with rat splenocytes 3 weeks before mating. The expression of TNF-alpha mRNA and protein was evaluated by in situ hybridization and immunohistochemistry techniques. RESULTS: The population of diabetic mice used in this study demonstrated a reduction in pregnancy rate and an increased number of litters with severely malformed fetuses. It has been observed that these disturbances are associated with a clear increase in TNF-alpha mRNA and protein expression in the uterus of these mice. Maternal immunopotentiation, while improving reproductive performance of these diabetic mice, was found to be accompanied by a reduced expression of TNF-alpha, both at the mRNA and protein level. CONCLUSIONS: The results of the present study suggest a possible involvement of TNF-alpha in mechanisms underlying diabetes-associated dismorphogenesis. Normalization of TNF-alpha expression by maternal immunopotentiation might represent a mechanism mediating its protective effect against diabetes-induced embryotoxic insult.

TGFbeta2 in embryos with inborn anomalies: effect of maternal immunopotentiation.

PROBLEM: TGFbetas are among the main immunoregulatory molecules contributing to successful embryonic development. Besides, our and other studies revealed that maternal immunopotentiation has a potential to increase the resistance of the embryo to the teratogenic insult. This work was designed to evaluate: (1) whether the formation of teratogen-induced anomalies is accompanied by an altered pattern of TGFbeta2 expression in embryonic cells and (2) whether maternal immunopotentiation modifies the pattern of TGFbeta2 expression in embryos responding to the teratogenic insult. METHOD OF STUDY: Experiments were performed in embryos of ICR mice exposed to 15 and 40 mg/kg of a reference teratogen, cyclophosphamide (CP) on day 12 of gestation. A group of mice was immunopotentiated with xenogeneic rat splenocytes 21 hr before the beginning of mating. Embryos were examined for the occurrence of gross structural anomalies 24 and 72 hr after CP treatment. Then, immunohistohemistry and in situ hybrydization assays were used to evaluate the expression of TGFbeta2 protein and mRNA in the brain, face, limbs and liver of these embryos. RESULTS: No external anomalies were observed in embryos examined 24 hr after CP treatment. Embryos examined 72 hr after CP treatment at 40 mg/kg exhibited agnathia, micrognathia, kinky tail, phocomelia, but no signs of dismorphogenesis were observed in the liver at the organ level. A significant increase in the expression of TGFbeta2 mRNA was observed in cells, residing in the brain, face and limbs but not in the liver of CP-exposed embryos tested 24 hr after CP injection in both doses. The level of TGFbeta2 protein in these embryos did not differ from that of controls. In embryos tested 72 hr after CP injection in the high dose both TGFbeta2 protein and mRNA expression were found to be elevated. Maternal immunopotentiation while enhancing the embryo's resistance to CP practically abolished an elevated expression of the TGFbeta2 mRNA detected in tested organ structures of embryos of non-immunopotentiated CP treated mice 24 hr after CP injection in both the low and the high doses. Also, a significant decrease in the level of TGFbeta2 mRNA expression was observed in embryos of immunopotentiated mice examined 72 hr after CP treatment. CONCLUSIONS: The results of this work show a possible involvement of TGFbeta2 in the formation of teratogen-induced structural anomalies and suggest that the stimulation of the maternal immune system may realize its protective effect by normalizing the level of TGFbeta2 expression in teratogen-targeted embryonic structures.

Ciprofloxacin affects pregnancy loss in CBA/JxDBA/2J mice possibly via elevation of interleukin-3 and granulocyte macrophage-colony stimulating factor production.

PROBLEM: The mechanisms mediating pregnancy loss are far from being understood, but it is believed that modulation of the maternal immune system, that is known to support pregnancy, might serve as a means for the treatment of habitual abortions. Thus, we examined the effect of the anti bacterial agent ciprofloxacin, which was shown to affect maternal immunoreactivity, on pregnancy loss in the resorption-prone CBA/JxDBA/2J mouse combination as well as associated changes in Interleukin (IL)-3 and Granulocyte macrophage-colony stimulating factor (GM-CSF) production. METHOD OF STUDY: CBA/J females mated to DBA/2J males were treated with ciprofloxacin for 5 consecutive days. On day 15 of pregnancy, the number of resorbed embryos was recorded and IL-3 mRNA expression as well as IL-3 and GM-CSF protein production by splenocytes were assayed by northern blotting and ELISA, respectively. RESULTS: Ciprofloxacin treatment resulted in a significant reduction in the resorption rate as compared to the effect of the control antibiotic ceftazidime or PBS only, while not affecting the number of implantation sites/mouse. Also, splenocytes from ciprofloxacin-treated CBA/J mice exhibited an increased level of IL-3 mRNA transcripts as well as an elevation in IL-3 and GM-CSF protein production. CONCLUSIONS: Our data demonstrate the ability of ciprofloxacin to reduce pregnancy loss in the CBA/JxDBA/2J mouse model, possibly via elevation of IL-3 and GM-CSF production.

Cellular events and the pattern of p53 protein expression following cyclophosphamide-initiated cell death in various organs of developing embryo.

This study was aimed at characterizing the temporal patterns of cell responses and p53 protein expression in the limbs, head, and liver of embryos responding to cyclophosphamide (CP)-induced teratogenic insult. ICR murine embryos were examined 24, 48, or 72 h after injection of 40 mg/kg CP on day 12 of pregnancy. The cellular events and temporal pattern of p53 protein expression were determined by FACS analysis and by TUNEL (apoptosis) in the head, limbs, and liver of the embryos. All tested organs showed apoptosis and a significantly decreased proportion of live cells after 24 h. Subsequent events were organ-dependent. In the liver, there were no dysmorphic events at any time and excessive cell death had been almost compensated for by 48 h. Compensation was preceded by G(1) arrest and accompanied by an increased level of p53 protein in surviving cells. Excessive cell death in the head and the limbs resulted in structural anomalies. In the head, there was an increased level of p53 protein and G(1) arrest after 24 h and the number of live cells at 48 h was equal to that seen in earlier samples, despite apoptosis. In the limbs, however, only isolated viable cells were seen by 48 h, but there was no increased level of p53 protein or G(1) arrest. Results of this study suggest that the differential sensitivity of tested organ systems to CP may be associated with differences in cellular events following CP-initiated cell death. They also suggest that the input of p53 in determining the response of these organ systems to CP-induced teratogenic insult may be different. Teratogenesis Carcinog. Mutagen. 19:353-367, 1999.

TGF beta 2 mRNA expression and pregnancy failure in mice.

PROBLEM: We describe here a pattern of transforming growth factor (TGF) beta2 mRNA expression at the fetomaternal interface in mice with high rate of resorptions as well as its expression following maternal immunopotentiation. METHOD OF STUDY: TGF beta 2 mRNA expression was evaluated in the uteroplacental units of mice with spontaneous (CBA/J x DBA/2J mouse combination) or cyclophosphamide (CP)-induced pregnancy loss. The effect of immunopotentiation on TGF beta 2 mRNA expression was determined in CP-treated females who underwent nonspecific immunostimulation with xenogeneic (rat) leukocytes. A quantitative analysis of TGF beta 2 mRNA level was performed using RNase protection assay. Distribution of TGF beta 2 mRNA transcripts at the fetomaternal interface was studied by in situ hybridization analysis. RESULTS: RNase protection analysis revealed four TGF beta 2 specific mRNA forms (330, 270, 230, and 170 bp) in the uteroplacental units of mice with either normal or decreased reproductive performance. A significant decrease (about 50%) in the level of TGF beta 2 mRNA was registered in the uteroplacental unit of mice with pregnancy loss as compared to the control mice. TGF beta 2 transcripts were abundant in the uterine epithelium and stroma. A specific hybridization signal was detected also in metrial gland cells and it was found to be substantially lower in CP-treated as compared to intact mice. In the resorbing uteroplacental unit, the expression of TGF beta 2 mRNA was completely lost in the uterine epithelium, and the number of TGF beta 2 mRNA-positive metrial gland cells was lower as compared to the control. Immunopotentiation decreased the resorption rate in mice with CP-induced pregnancy loss and caused a dramatic increase in TGF beta 2 mRNA expression: the level of TGF beta 2 mRNA was found to be higher by 2.0-3.2 fold in the uteroplacental unit of immunized as compared to nonimmunized CP-treated mice. CONCLUSIONS: These data suggest that distortion of TGF beta 2 expression at the fetomaternal interface may be associated with pregnancy failure. It seems that beneficial effect of maternal immunostimulation may at least partly be due to the strong increase in TGF beta 2 mRNA expression at the fetomaternal interface.

Colony-stimulating factor-1 (CSF-1) expression in the uteroplacental unit of mice with spontaneous and induced pregnancy loss.

CSF-1 plays an important role in female reproduction and normal embryo development. To understand further CSF-1 function in normal and, especially, in compromised pregnancy, we studied the pattern of its mRNA expression as well as expression of its receptor (c-fms) in the uteroplacental units of mice with induced (cyclophosphamide (CY)-treated) and spontaneous (CBA/J x DBA/2J mating combination) pregnancy loss. RNase protection analysis demonstrated the presence of two forms of CSF-1 mRNA in the uteroplacental unit corresponding to 1400- and 263-bp protective fragments. Densitometric analysis demonstrated that the level of 1400-bp mRNA form was decreased by 40% in the uteroplacental units of mice with CY-induced pregnancy loss compared with the control mice. About 20% decrease in 263-bp protective fragment was registered in resorbing versus non-resorbed placenta of CBA/J females mated to DBA/2J males. As judged by in situ hybridization assay, CSF-1 mRNA transcripts were localized in the uterine epithelium and stroma, while c-fms mRNA was found mainly in the trophoblast. The number of metrial gland cells as well as the number of uterine leucocytes expressing CSF-1 and c-fms mRNAs was substantially lower in the uteroplacental unit of mice with pregnancy loss than in control animals. Maternal immunostimulation, while significantly decreasing the resorption rate in mice with CY-induced pregnancy loss, also strengthened CSF-1 mRNA expression at the fetomaternal interface and resulted in reconstitution in the number of CSF-1+ uterine leucocytes and metrial gland cells. These data suggest a role for uterine CSF-1 in the physiology of normal and compromised pregnancy and demonstrate a possible involvement of CSF-1-associated signalling in mechanisms of placenta and endometrium repair following immunopotentiation.

A possible role for granulocyte macrophage-colony stimulating factor in modulating teratogen-induced effects.

It was already shown that stimulation of the maternal immune system by allogeneic or xenogeneic leukocytes is capable of affecting embryonic responses to teratogenic insults and various cytokines, including granulocyte macrophage-colony stimulating factor (GM-CSF), were implicated as mediators of this effect. Therefore, in the present study we tried to assess the ability of GM-CSF to modulate teratogenic activity, along with possible changes in systemic as well as local maternal immune responses, that might be involved in the process. Thus, the percentage of cyclophosphamide (CP)-treated embryos exhibiting limb malformations was shown to decrease significantly following GM-CSF administration. This effect was found to be comparable to that demonstrated by intrauterine leukocytes administration. GM-CSF treatment resulted in a significant enhancement in maternal splenocytes Con-A-induced proliferation, as well as Interleukin-2 (IL-2) and IL-3 production. Examination of leukocyte cell surface antigens expressed by splenocytes revealed no statistically-significant changes in the level of the T lymphoid antigens Thy-1, CD5, CD4, CD8 and CD3, the macrophage antigen Mac-1, and the adhesion molecules LFA-1alpha, LFA-1beta and L-Selectin, following GM-CSF immunostimulation. In parallel, immunohistochemical analysis of the uteroplacental unit revealed Mac-1 and to a lesser extent LFA-1beta-positive cells localized to the myometrium and the placenta in both the control and the GM-CSF-treated groups, while no cells expressing Thy-1, CD3, CD4, CD8, or LFA-1alpha could be demonstrated. Our results suggest a possible role for GM-CSF in modulating teratogen-induced effects, a process in which maternal immune responses such as splenocytes proliferation and cytokine production might be involved.

Maternal immunopotentiation affects the teratogenic response to hyperthermia.

Immune responses occurring between the embryo and mother have been shown to influence the embryo's tolerance to teratogens, including chemical teratogens and diabetes-induced teratogenic insult. In this study, we tried to evaluate whether maternal immunostimulation alters the embryo's response to heat shock, one of few teratogens which directly affect the embryo. In order to induce structural anomalies, both intact ICR female mice and mice which had been immunostimulated with xenogeneic rat splenocytes before mating, were exposed to two consecutive exposures to heat (43.6 +/- 0.2 degrees C) for 10 min on day 9 of pregnancy. The number of malformed fetuses, resorptions, and fetal weight were assessed on day 19 of pregnancy. Heat shock-induced apoptosis, and the level of heat shock protein (HSP) 60 expression, were examined in embryonic cells at different time points within 24 h after heating. All these indices differed dramatically in immunized and non-immunized heat shocked females. Heat shocked non-immunized females demonstrated an increased level of resorptions (approximately, 21% versus 8.6% in controls) and the proportion of fetuses with such anomalies as encephalocele and open eyes reached 28% and 21%, respectively. Maternal immunostimulation was associated with a significant decrease in the proportion of fetuses with encephalocele (12.8%), open eyes (8.9%), and resorptions (8%). The maximum level of heat shock-induced apoptosis in cell populations from the embryos of non-immunized females, was approximately, 30% versus 7% in cells of embryos of immunized mice. Heat shock was also followed by a significant increase in HSP60 expression, but only in the cells of embryos of non-immunized females. Together, these findings suggest that the tolerance of mouse embryos to a heat shock-induced teratogenic insult may, to some extent, depend on the character of the maternal immune responses.

Acute immunosuppression and syngeneic bone marrow transplantation in ocular autoimmunity abort disease, but do not result in induction of long-term protection.

Acute immunosuppression induced by total body irradiation (TBI) or cyclophosphamide (Cy) treatment, followed by syngeneic bone marrow transplantation (SBMT), was reported to be effective in inducing long-term tolerance in some autoimmune disease models. We examined the efficacy of this approach in the mouse model of experimental autoimmune uveoretinitis (EAU). Development of EAU induced by the interphotoreceptor retinoid binding protein (IRBP) was abolished almost completely by either TBI or Cy treatment, followed by SBMT, instituted one week after priming. In parallel, IRBP-specific delayed-type hypersensitivity (DTH) responses and lymph node cell proliferation were strongly suppressed or abolished. However, when these IRBP-immunized, lymphoablated and BM reconstituted mice were rechallenged with the immunizing antigen seven weeks after the primary immunization, they were not protected from developing disease, despite the fact that DTH and lymph node cell proliferation to the antigen were suppressed relative to controls. TBI treatment appeared somewhat more effective than Cy treatment as judged by its more profound effect on immunological responses. These results demonstrate the ability of acute immunosuppression followed by reconstitution of the immune system to inhibit the development of EAU, although long-term protection from disease was not achieved.

TNF-alpha messenger RNA and protein expression in the uteroplacental unit of mice with pregnancy loss.

An elevated expression of TNF-alpha in embryonic microenvironment was found to be associated with postimplantation loss. In this work, we examined the pattern of TNF-alpha expression at both the mRNA and the protein level as well as the distribution of TNF-alpha receptor mRNA in the uteroplacental unit of mice with induced (cyclophosphamide-treated) or spontaneous (CBA/J x DBA/2J mouse combination) pregnancy loss. RNase protection analysis demonstrated an increase in TNF-alpha mRNA expression in the placentae of mice with pregnancy loss compared with that in control mice. TNF-alpha messages were localized to the uterine epithelium and stroma as well as the giant and spongiotrophoblast cells of the placenta. The intensity of the hybridization signal in placentae of mice with pregnancy loss was substantially higher than that in control mice. The up-regulation of TNF-alpha mRNA was accompanied by an increase in the expression of TNF-alpha receptor I mRNA in the same cell populations. The elevation of TNF-alpha production was also demonstrated at the protein level. Western blot analysis showed an increased level of the 18- and 26-kDa TNF-alpha protein species in the uteroplacental unit of mice with pregnancy loss. Immunostaining revealed TNF-alpha-positive leukocytes located in the uterus and placenta. Finally, we found that immunization of mice with cyclophosphamide-induced pregnancy loss while decreasing the resorption rate in these females resulted in a decline in TNF-alpha expression at the fetomaternal interface. These data clearly suggest an involvement of TNF-alpha in pathways leading to both spontaneous and induced placental death.

Ciprofloxacin immunomodulation of experimental antiphospholipid syndrome associated with elevation of interleukin-3 and granulocyte-macrophage colony-stimulating factor expression.

OBJECTIVE: To evaluate the immunomodulatory potential of ciprofloxacin in mice with experimental antiphospholipid syndrome (APS). METHODS: Ciprofloxacin or ceftazidime (control antibiotic) was given to mice with experimentally induced APS. The titers of autoantibodies, levels of cytokines, and number of cytokine-producing cells were determined by enzyme-linked immunosorbent assay. Myeloid progenitor cells were determined by granulocyte-macrophage colony-forming unit, and interleukin-3 (IL-3) messenger RNA (mRNA) was tested by Northern analysis. RESULTS: A decrease in the incidence of pregnancy loss and an improvement in the clinical manifestations of APS were noted in the mice treated with ciprofloxacin, compared with the mice given ceftazidime. The effect of ciprofloxacin was found to be associated with increased serum levels of IL-3 and with increased IL-3 mRNA transcription in the splenocytes. Expression of granulocyte-macrophage colony-stimulating factor (GM-CSF) was documented by elevated titers in the sera and elevated numbers of colony-forming cells in the bone marrow. CONCLUSION: Ciprofloxacin prevents the manifestations of experimental APS. This effect may be associated with increased IL-3 levels and GM-CSF expression.