Zfp148 deficiency causes lung maturation defects and lethality in newborn mice that are rescued by deletion of p53 or antioxidant treatment

The transcription factor Zfp148 (Zbp-89, BFCOL, BERF1, htβ) interacts physically with the tumor suppressor p53 and is implicated in cell cycle control, but the physiological role of Zfp148 remains unknown. Here we show that Zfp148 deficiency leads to respiratory distress and lethality in newborn mice. Zfp148 deficiency prevented structural maturation of the prenatal lung without affecting type II cell differentiation or surfactant production. BrdU analyses revealed that Zfp148 deficiency caused proliferation arrest of pulmonary cells at E18.5–19.5. Similarly, Zfp148-deficient fibroblasts exhibited proliferative arrest that was dependent on p53, raising the possibility that cell stress is part of the underlying mechanism. Indeed, Zfp148 deficiency lowered the threshold for activation of p53 under oxidative conditions. Moreover, both in vivo and cellular phenotypes were rescued on Trp53^+/− or Trp53^−/− backgrounds and by antioxidant treatment. Thus, Zfp148 prevents respiratory distress and lethality in newborn mice by attenuating oxidative stress–dependent p53-activity during the saccular stage of lung development. Our results establish Zfp148 as a novel player in mammalian lung maturation and demonstrate that Zfp148 is critical for cell cycle progression in vivo.

Evaluation of developmental toxicity studies of glyphosate with attention to cardiovascular development

The herbicide glyphosate has undergone multiple safety tests for developmental toxicity in rats and rabbits. The European Commission's 2002 review of available glyphosate data discusses specific heart defects observed in several individual rabbit developmental toxicity studies, but describes the evidence for a potential causal relationship as equivocal. The present assessment was undertaken to analyze the current body of information generated from seven unpublished rabbit studies in order to determine if glyphosate poses a risk for cardiovascular malformations. In addition, the results of six unpublished developmental toxicity studies in rats were considered. Five of the seven rabbit studies (dose range: 10-500 mg/kg/day) were GLP- and testing guideline-compliant for the era in which the studies were performed; a sixth study predated testing and GLP guidelines, but generally adhered to these principles. The seventh study was judged inadequate. In each of the adequate studies, offspring effects occurred only at doses that also caused maternal toxicity. An integrated evaluation of the six adequate studies, using conservative assumptions, demonstrated that neither the overall malformation rate nor the incidence of cardiovascular malformations increased with dose up to the point where severe maternal toxicity was observed (generally ≥150 mg/kg/day). Random occurrences of cardiovascular malformations were observed across all dose groups (including controls) and did not exhibit a dose-response relationship. In the six rat studies (dose range: 30-3500 mg/kg/day), a low incidence of sporadic cardiovascular malformations was reported that was clearly not related to treatment. In summary, assessment of the entire body of the developmental toxicity data reviewed fails to support a potential risk for increased cardiovascular defects as a result of glyphosate exposure during pregnancy.

High osmolality vitrification: a new method for the simple and temperature-permissive cryopreservation of mouse embryos

Procedures for cryopreserving embryos vary considerably, each having its specific advantages and disadvantages in terms of technical feasibility, embryo survival yield, temperature permissibility and species- or strain-dependent applicability. Here we report a high osmolality vitrification (HOV) method that is advantageous in these respects. Cryopreservation by vitrification is generally very simple, but, unlike slow freezing, embryos should be kept at a supercooling temperature (below –130°C) to avoid cryodamage. We overcame this problem by using an HOV solution containing 42.5% (v/v) ethylene glycol, 17.3% (w/v) Ficoll and 1.0 M sucrose. This solution is more viscous than other cryopreservation solutions, but easy handling of embryos was assured by employing a less viscous equilibration solution before vitrification. Most (>80%) embryos cryopreserved in this solution survived at –80°C for at least 30 days. Normal mice were recovered even after intercontinental transportation in a conventional dry-ice package for 2–3 days, indicating that special containers such as dry shippers with liquid nitrogen vapor are unnecessary. The HOV solution could also be employed for long-term storage in liquid nitrogen, as with other conventional cryoprotectants. Finally, we confirmed that this new vitrification method could be applied successfully to embryos of all six strains of mice we have tested so far. Thus, our HOV method provides an efficient and reliable strategy for the routine cryopreservation of mouse embryos in animal facilities and biomedical laboratories, and for easy and cheap transportation.

Prenatal and developmental effect of high molecular weight chitosan (HMWCS) to mice

High molecular weight chitosan (HMWCS) is effective at hemostasis and wound healing, and will be potentially used on injured internal organs. To study its prenatal and developmental effect in vivo, forty-four ICR pregnant mice per group were singly injected intraperitoneally at 0, 125, 500 or 2000 mg/kg body weight, respectively, on gestation day 6 (GD6). Clinical signs, reproductive capacity, fetus and infant developments, and histopathological changes were then observed. The results showed that the treatment of HMWCS could decrease body weights and food consumptions, and induce diarrhea, vaginal bleeding, and some other adverse effects in F0 mice. For the emaciation and threatened abortion of pregnant mice, the numbers of live fetuses and early resorption were reduced significantly in HMWCS groups. However, the developments of F1 and F2 mice were not affected, except for lower weights of the body and some organs. In addition, the NOAEL of HMWCS in maternal toxicity was considered to be less than 125 mg/kg, and the NOAEL in developmental toxicity was 125 mg/kg.

Effects of melatonin on superovulation and transgenic embryo transplantation in small-tailed han sheep (Ovis aries)

OBJECTIVE

In this study, the effects of melatonin on superovulation and the transfer of transgenic embryos were investigated in Small-Tailed Han sheep.

DESIGN

Different doses of melatonin (0, 40 or 80 mg/animal) were subcutaneously implanted into both multiparous (4-5 years old) donors and recipients before superovulation and estrus synchronization. The one-year-old young ewes without melatonin treatment served to evaluate the reproductive efficiency of the adult multiparous ewes. Ewes with superovulation were used as embryo donors. The estrus were induced in embryo recipients after embryo transpimplanted.

RESULTS

The results showed that the number of corpora lutea of the ewes received subcutaneous 40 or 80 mg melatonin implant (13.4±1.05/ewe, 15.1±1.62/ewe) were significantly higher than that of in control group (8.8±0.37/ewe) (p<0.05). Similarily the number of recovered embryos from the ewes received subcutaneous 40 or 80 mg melatonin implant (10.3±0.84/ewe, 10.9±1.21/ewe) was significantly higher than the control group (6.2±0.60/ewe) (p<0.05). The transimplantd embryos from 40 or 80 mg melatonin treated donors dramatically improved the pregnancy and birth rates compared to control ewes. In addition, both 40 mg and 80 mg melatonin implatation lead to more lambs born per embryo.

CONCLUSIONS

These observations provide valuable information for the application of melatonin in increasing superovulation and transgenic embryo transplantation efficiency in sheep.

Frog embryo teratogenesis assay on Xenopus and predictivity compared with in vivo mammalian studies

Frog embryo teratogenesis assay on Xenopus (FETAX) has been routinely used in our laboratory for the last 12 years as a routine developmental toxicity screening test for pharmaceutical candidate compounds. To date, out of more than 400 candidates tested in FETAX, around 60 have also been evaluated in mammalian embryotoxicity studies according to standard ICH protocols.Compound teratogenic potential in both FETAX and mammalian embryotoxicity studies is determined after analysis of the developmental toxicity characterized by embryotoxicity, growth delay, and/or potential to induce malformations. Based on this experience, the predictivity of FETAX is 81% with a minimal proportion of false positive results.

Porcine induced pluripotent stem cells require LIF and maintain their developmental potential in early stage of embryos

Porcine induced pluripotent stem (piPS) cell lines have been generated recently by using a cocktail of defined transcription factors, however, the features of authentic piPS cells have not been agreed upon and most of published iPS clones did not meet the stringent requirements of pluripotency. Here, we report the generation of piPS cells from fibroblasts using retrovirus carrying four mouse transcription factors (mOct4, mSox2, mKlf4 and mc-Myc, 4F). Multiple LIF-dependent piPS cell lines were generated and these cells showed the morphology similar to mouse embryonic stem cells and other pluripotent stem cells. In addition to the routine characterization, piPS cells were injected into porcine pre-compacted embryos to generate chimera embryos and nuclear transfer (NT) embryos. The results showed that piPS cells retain the ability to integrate into inner and outer layers of the blastocysts, and support the NT embryos development to blastocysts. The generations of chimera embryos and NT embryos derived from piPS clones are a practical means to determine the quality of iPS cells ex vivo.

Knockout of insulin-like growth factor-1 receptor impairs distal lung morphogenesis

Background

Insulin-like growth factors (IGF-I and -II) are pleiotropic regulators of somatic growth and development in vertebrate species. Endocrine and paracrine effects of both hormones are mediated by a common IGF type 1 receptor (IGF-1R). Lethal respiratory failure in neonatal IGF-1R knockout mice suggested a particular role for this receptor in pulmonary development, and we therefore investigated the consequences of IGF-1R inactivation in lung tissue.

Methods and Findings

We first generated compound heterozygous mutant mice harboring a hypomorphic (Igf1r^neo) and a null (Igf1r⁻) allele. These IGF-1R^neo/− mice express only 22% of normal IGF-1R levels and are viable. In adult IGF-1R^neo/− mice, we assessed lung morphology and respiratory physiology and found normal histomorphometric characteristics and normal breathing response to hypercapnia. We then generated homozygous IGF-1R knockout mutants (IGF-1R^−/−) and analyzed their lung development during late gestation using histomorphometric and immunohistochemical methods. IGF-1R^−/− embryos displayed severe lung hypoplasia and markedly underdeveloped diaphragms, leading to lethal neonatal respiratory distress. Importantly, IGF-1R^−/− lungs from late gestation embryos were four times smaller than control lungs and showed markedly thickened intersaccular mesenchyme, indicating strongly delayed lung maturation. Cell proliferation and apoptosis were significantly increased in IGF-1R^−/− lung tissue as compared with IGF-1R^+/+ controls. Immunohistochemistry using pro-SP-C, NKX2-1, CD31 and vWF as markers revealed a delay in cell differentiation and arrest in the canalicular stage of prenatal respiratory organ development in IGF-1R^−/− mutant mice.

Conclusions/Significance

We found that low levels of IGF-1R were sufficient to ensure normal lung development in mice. In contrast, complete absence of IGF-1R significantly delayed end-gestational lung maturation. Results indicate that IGF-1R plays essential roles in cell proliferation and timing of cell differentiation during fetal lung development.

Zinc supplementation prevents cardiomyocyte apoptosis and congenital heart defects in embryos of diabetic mice

Oxidative stress induced by maternal diabetes plays an important role in the development of cardiac malformations. Zinc (Zn) supplementation of animals and humans has been shown to ameliorate oxidative stress induced by diabetic cardiomyopathy. However, the role of Zn in the prevention of oxidative stress induced by diabetic cardiac embryopathy remains unknown. We analyzed the preventive role of Zn in diabetic cardiac embryopathy by both in vivo and in vitro studies. In vivo study revealed a significant decrease in lipid peroxidation, superoxide ions, and oxidized glutathione and an increase in reduced glutathione, nitric oxide, and superoxide dismutase in the developing heart at embryonic days (E) 13.5 and 15.5 in the Zn-supplemented diabetic group when compared to the diabetic group. In addition, significantly down-regulated protein and mRNA expression of metallothionein (MT) in the developing heart of embryos from diabetic group was rescued by Zn supplement. Further, the nuclear microscopy results showed that trace elements such as phosphorus, calcium, and Zn levels were significantly increased (P<0.001), whereas the iron level was significantly decreased (P<0.05) in the developing heart of embryos from the Zn-supplemented diabetic group. In vitro study showed a significant increase in cellular apoptosis and the generation of reactive oxygen species (ROS) in H9c2 (rat embryonic cardiomyoblast) cells exposed to high glucose concentrations. Supplementation with Zn significantly decreased apoptosis and reduced the levels of ROS. In summary, oxidative stress induced by maternal diabetes could play a role in the development and progression of cardiac embryopathy, and Zn supplementation could be a potential therapy for diabetic cardiac embryopathy.

H₂O₂ lowers the cytosolic Ca²⁺ concentration via activation of cGMP-dependent protein kinase Iα

The cGMP-dependent protein kinase I (cGKI) is a key mediator of cGMP signaling, but the specific functions of its two isoforms, cGKIα and cGKIβ, are poorly understood. Recent studies indicated a novel cGMP-independent role for cGKIα in redox sensing. To dissect the effects of oxidative stress on the cGKI isoforms, we used mouse embryonic fibroblasts and vascular smooth muscle cells (VSMCs) expressing both, one, or none of them. In cGKIα-expressing cells, but not in cells expressing only cGKIβ, incubation with H₂O₂ induced the formation of a disulfide bond between the two identical subunits of the dimeric enzyme. Oxidation of cGKIα was associated with increased phosphorylation of its substrate, vasodilator-stimulated phosphoprotein. H₂O₂ did not stimulate cGMP production, indicating that it activates cGKIα directly via oxidation. Interestingly, there was a mutual influence of H₂O₂ and cGMP on cGKI activity and disulfide bond formation, respectively; preoxidation of the kinase with H₂O₂ slightly impaired its activation by cGMP, whereas preactivation of the enzyme with cGMP attenuated its oxidation by H₂O₂. To evaluate the functional relevance of the noncanonical H₂O₂-cGKIα pathway, we studied the regulation of the cytosolic Ca²⁺ concentration ([Ca²⁺](i)). H₂O₂ suppressed norepinephrine-induced Ca²⁺ transients in cGKIα-expressing VSMCs and, to a lower extent, in VSMCs expressing only cGKIβ or none of the isoforms. Thus, H₂O₂ lowers [Ca²⁺](i) mainly via a cGKIα-dependent pathway. These results indicate that oxidative stress selectively targets the cGKIα isoform, which then modulates cellular processes in a cGMP-independent manner. A decrease in [Ca²⁺](i) in VSMCs via activation of cGKIα might be a major mechanism of H₂O₂-induced vasodilation.

[Effects of strontium chloride activation on the cleavage rate and somatic cell nuclear transfer embryos in mice]

OBJECTIVE

To establish a suitable protocol for activating mouse somatic cell nuclear transfer embryos with strontium chloride (SrCl2).

METHODS

We constructed and identified mouse nuclear transfer (NT) embryos. After nuclear injection, we activated the NT embryos using the following chemical activation methods: exposing the NT embryos to 5 and 10 mmol/L SrCl2 strontium for 1 -8 h, activating the NT embryos with 1-20 mmol/L SrCl2 strontium at 4 and 6 h, treating the NT embryos with 10 mmol/L SrCl2 strontium in different activating media, and exposing the NT embryos to 10 mmol/L SrCl2 strontium combined with 6-dimethylaminopurine (6-DMAP) and cytochalasin B (CB). After activation, the NT embryos were cultured in vitro in the cleavage medium.

RESULTS

When the NT embryos were treated with SrCl2 at the concentration of 5 mmol/L, the cleavage rate was remarkably higher at 6 h (38.9%) than at 1 h (6.7%), 2 h (22.8%), 3 h (22.8%) and 4 h (25.6%) (P < 0.05), but with no significant differences from those at 5 h (28.9%), 7 h (34.4%) and 8 h (28.9%) (P > 0.05). When the NT embryos were treated with SrCl2 for 6 h, the rates of cleavage and blastulation were 68.9% and 7.2% at 10 mmol/L, markedly higher than at 1 mmol/L (28.3% and 0%), 2.5 mmol/L (35.6% and 0%), 5 mmol/L (37.8% and 1.1%), 7.5 mmol/L (60.6% and 2.2%), 15 mmol/L (51.7% and 1.1%), and 20 mmol/L (41.7% and 1.1%) (P < 0.05). The cleavage rate of the NT embryos cultured in the Ca2+ and Mg2+ KSOM medium was 27.8%, significantly lower than in the Ca(2+)-free KSOM (69.4%), Ca2+/Mg(2+)-free KSOM (66.1%), and Ca2+/Mg(2+)-free + EDTA KSOM (68.3%) (P < 0.05). The total cell blastocyst number was significantly larger in the NT embryos treated with SrCl2 + CB (45.40 +/- 2.23) than in those treated with SrCl2 (30.15 +/- 1.12), 6-DMAP (34.95 +/- 1.38), and 6-DMAP + CB (37.45 +/- 1.43) (P < 0.05).

CONCLUSION

Six-hour treatment with 10 mmol/L SrCl2 in Ca2+ alone or in combination with CB can well activate NT embryos in mice.

Bmp indicator mice reveal dynamic regulation of transcriptional response

Cellular responses to Bmp ligands are regulated at multiple levels, both extracellularly and intracellularly. Therefore, the presence of these growth factors is not an accurate indicator of Bmp signaling activity. While a common approach to detect Bmp signaling activity is to determine the presence of phosphorylated forms of Smad1, 5 and 8 by immunostaining, this approach is time consuming and not quantitative. In order to provide a simpler readout system to examine the presence of Bmp signaling in developing animals, we developed BRE-gal mouse embryonic stem cells and a transgenic mouse line that specifically respond to Bmp ligand stimulation. Our reporter identifies specific transcriptional responses that are mediated by Smad1 and Smad4 with the Schnurri transcription factor complex binding to a conserved Bmp-Responsive Element (BRE), originally identified among Drosophila, Xenopus and human Bmp targets. Our BRE-gal mES cells specifically respond to Bmp ligands at concentrations as low as 5 ng/ml; and BRE-gal reporter mice, derived from the BRE-gal mES cells, show dynamic activity in many cellular sites, including extraembryonic structures and mammary glands, thereby making this a useful scientific tool.

Effect of di-(2-ethylhexyl) phthalate and mono-(2-ethylhexyl) phthalate on in vitro developmental competence of bovine oocytes

In the last decade, potential exposure of humans and animals to industrial chemicals and pesticides has been a growing concern. In the present study, di-(2-ethylhexyl) phthalate (DEHP) and mono-(2-ethylhexyl) phthalate (MEHP) were used to model the effects of endocrine-disrupting compounds and their risk in relation to early embryonic losses. Exposure of cumulus oocyte complexes during maturation to 50 μM MEHP reduced the proportion of oocytes that underwent nuclear maturation (p < 0.05) and increased the proportion of apoptotic oocytes (p < 0.05). Furthermore, phthalates reduced cleavage rate in the MEHP-treated group (p < 0.05) and the proportion of embryos developing to the blastocyst stage in both DEHP- and MEHP-treated groups (p < 0.05). The total cell count for blastocysts developing from MEHP-treated oocytes was lower than in controls (p < 0.05). Exposure of oocytes to MEHP during maturation reduced (p < 0.05) the expression of ASAH1 (an anti-apoptotic factor), CCNA2 (involved in cell cycle control), and POU5F1 (responsible for pluripotency) in matured oocytes. Furthermore, the reduced mRNA expression of POU5F1 and ASAH1 lasted into two-cell stage embryos (p < 0.05). Phthalate-induced alterations in POU5F1, ASAH1, and CCNA2 expression might explain in part the reduced developmental competence of MEHP-treated oocytes.

Gender differences in transcriptional signature of developing rat testes and ovaries following embryonic exposure to 2,3,7,8-TCDD

Dioxins are persistent organic pollutants interfering with endocrine systems and causing reproductive and developmental disorders. The objective of our project was to determine the impact of an in utero exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on reproductive function of male and female offspring in the rat with a special emphasis on the immature period. We used a low dose of TCDD (unique exposure by oral gavage of 200 ng/kg at 15.5 days of gestation) in order to mirror a response to an environmental dose of TCDD not altering fertility of the progeny. We choose a global gene expression approach using Affymetrix microarray analysis, and testes of 5 days and ovaries of 14 days of age. Less than 1% of the expressed genes in gonads were altered following embryonic TCDD exposure; specifically, 113 genes in ovaries and 56 in testes with 7 genes common to both sex gonads. It included the repressor of the aryl hydrocarbon receptor (Ahrr), the chemokines Ccl5 and Cxcl4 previously shown to be regulated by dioxin in testis, Pgds2/Hpgds and 3 others uncharacterized. To validate and extend the microarray data we realized real-time PCR on gonads at various developmental periods of interest (from 3 to 25 days for ovaries, from 5 to the adult age for testes). Overall, our results evidenced that both sex gonads responded differently to TCDD exposure. For example, we observed induction of the canonic battery of TCDD-induced genes coding enzymes of the detoxifying machinery in ovaries aged of 3–14 days of age (except Cyp1a1 induced at 3–10 days) but not in testes of 5 days (except Ahrr). We also illustrated that inflammatory pathway is one pathway activated by TCDD in gonads. Finally, we identified several new genes targeted by TCDD including Fgf13 in testis and one gene, Ptgds2/Hpgds regulated in the two sex gonads.

Crebinostat: a novel cognitive enhancer that inhibits histone deacetylase activity and modulates chromatin-mediated neuroplasticity

Long-term memory formation is known to be critically dependent upon de novo gene expression in the brain. As a consequence, pharmacological enhancement of the transcriptional processes mediating long-term memory formation provides a potential therapeutic strategy for cognitive disorders involving aberrant neuroplasticity. Here we focus on the identification and characterization of small molecule inhibitors of histone deacetylases (HDACs) as enhancers of CREB (cAMP response element-binding protein)-regulated transcription and modulators of chromatin-mediated neuroplasticity. Using a CREB reporter gene cell line, we screened a library of small molecules structurally related to known HDAC inhibitors leading to the identification of a probe we termed crebinostat that produced robust activation of CREB-mediated transcription. Further characterization of crebinostat revealed its potent inhibition of the deacetylase activity of recombinant class I HDACs 1, 2, 3, and class IIb HDAC6, with weaker inhibition of the class I HDAC8 and no significant inhibition of the class IIa HDACs 4, 5, 7, and 9. In cultured mouse primary neurons, crebinostat potently induced acetylation of both histone H3 and histone H4 as well as enhanced the expression of the CREB target gene Egr1 (early growth response 1). Using a hippocampus-dependent, contextual fear conditioning paradigm, mice systemically administered crebinostat for a ten day time period exhibited enhanced memory. To gain insight into the molecular mechanisms of memory enhancement by HDAC inhibitors, whole genome transcriptome profiling of cultured mouse primary neurons treated with crebinostat, combined with bioinformatic analyses of CREB-target genes, was performed revealing a highly connected protein-protein interaction network reflecting modules of genes important to synaptic structure and plasticity. Consistent with these findings, crebinostat treatment increased the density of synapsin-1 punctae along dendrites in cultured neurons. Finally, crebinostat treatment of cultured mouse primary neurons was found to upregulate Bdnf (brain-derived neurotrophic factor) and Grn (granulin) and downregulate Mapt (tau) gene expression-genes implicated in aging-related cognitive decline and cognitive disorders. Taken together, these results demonstrate that crebinostat provides a novel probe to modulate chromatin-mediated neuroplasticity and further suggests that pharmacological optimization of selective of HDAC inhibitors may provide an effective therapeutic approach for human cognitive disorders. This article is part of a Special Issue entitled 'Cognitive Enhancers'.

The effects of intravenous anesthetics on mouse embryonic fibroblast viability and proliferation

PURPOSE

The aim of this study is to evaluate the cytotoxic and antiproliferating effects of intravenous anesthetics on an mouse fibroblast in vitro cell culture system.

METHODS

The cells were exposed to the usual clinical plasma concentration of intravenous anesthetics, i.e., midazolam (0.15 μg/ml), propofol (2 μg/ml), remifentanil (2 μg/ml), thiopental (10 μg/ml), for 4, 8, or 24 h. Cell proliferation (n = 6 for each) under intravenous anesthetics was analyzed using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Cytotoxicity (n = 6 for each) of intravenous anesthetics was investigated using a LIVE/DEAD viability assay kit.

RESULTS

Intravenous anesthetic exposure time did not affect the proliferation rate of mouse fibroblasts. The cytotoxicity of intravenous anesthetics did not differ in accordance with exposure time.

CONCLUSION

Our results showed that intravenous anesthetics may not affect mouse fibroblast proliferation and viability.

Induced Wnt5a expression perturbs embryonic outgrowth and intestinal elongation, but is well-tolerated in adult mice

Wnt5a is essential during embryonic development, as indicated by mouse Wnt5a knockout embryos displaying outgrowth defects of multiple structures including the gut. The dynamics of Wnt5a involvement in these processes is unclear, and perinatal lethality of Wnt5a knockout embryos has hampered investigation of Wnt5a during postnatal stages in vivo. Although in vitro studies have suggested a relevant role for Wnt5a postnatally, solid evidence for a significant impact of Wnt5a within the complexity of an adult organism is lacking. We generated a tightly-regulated inducible Wnt5a transgenic mouse model and investigated the effects of Wnt5a induction during different time-frames of embryonic development and in adult mice, focusing on the gastrointestinal tract. When induced in embryos from 10.5 dpc onwards, Wnt5a expression led to severe outgrowth defects affecting the gastrointestinal tracts, limbs, facial structures and tails, closely resembling the defects observed in Wnt5a knockout mice. However, Wnt5a induction from 13.5 dpc onwards did not cause this phenotype, indicating that the most critical period for Wnt5a in embryonic development is prior to 13.5 dpc. In adult mice, induced Wnt5a expression did not reveal abnormalities, providing the first in vivo evidence that Wnt5a has no major impact on mouse intestinal homeostasis postnatally. Protein expression of Wnt5a receptor Ror2 was strongly reduced in adult intestine compared to embryonic stages. Moreover, we uncovered a regulatory process where induction of Wnt5a causes downregulation of its receptor Ror2. Taken together, our results indicate a role for Wnt5a during a restricted time-frame of embryonic development, but suggest no impact during homeostatic postnatal stages.

[Effect of change in activity level of catecholaminergic systems on motor, respiratory, and cardiac activities in rat embryos]

Parameters of motor, respiratory and cardiac activities were studied in rat embryos (E17-20) after changes in activity level of catecholaminergic systems. To produce conditions for excessive level of catecholamines, the animal were administered individually with preparation of L-DOPA at doses of 25, 50 and 100 mg/kg. Also studied was action of L-DOPA after blockade of D1-(antagonist - SCH-23390, 0.1 mg/kg), D2-(antagonist - sulpiride, 50 mg/kg) dopaminic, and beta2-(antagonist - propranolol, 1 mg/kg) adrenergic receptors. It was found out in E17-18 that the DOPA administration regardless of dose, while in E19-20 dose-dependently produces continuous generalized activity. Between E18 and E19, ontogenetically new is the appearance in 92 % of embryos of stereotypical head movements (circular movements, lateral and dorso-ventral flexions) following in the nearsecond rhythm. Injection of DOPA to rat embryos increased 2-6 times the number of respiratory movements by the gasping type in E17-20 and decreased the amount of episodes of continuous rhythmical respiration in E19-20. No significant heart rate changes were observed after introduction of DOPA to E17-20. There was noted a tendency for a weak acceleration of the heart rate. The changes in activities of the motor and respiratory systems due to a rise of catecholamine level are not connected with activation of the dopamine system, as they are not reduced by blockade of dopamine receptors.

Bone loss in adult offspring induced by low-dose exposure to teratogens

Maternal malnutrition during pregnancy was shown by numerous studies to result in the birth of offspring exhibiting altered bone characteristics, which are indicative of bone loss. We hypothesized that not only maternal malnutrition but also some developmental toxicants (teratogens) given at a dose inducing neither structural anomalies nor growth retardation can detrimentally affect skeletal health in adult offspring. To check this hypothesis, pregnant mice were exposed to a single injection of 5-aza-2-deoxycytidine (5-AZA) (a teratogen capable of inducing phocomelia of the hind limbs) at a sub-threshold teratogenic dose. Micro-computed tomography scanning revealed that femora of 5-month-old male offspring exposed in uterus to 5-AZA had trabecular microarchitecture indicative of bone loss. Furthermore, exposure to 5-AZA increased the susceptibility of offspring to postnatal chronic mild stress, which has been shown to induce bone loss in mice. While exploring possible mechanisms underlying this phenomenon, we observed that the expression of some microRNAs, which have been demonstrated as regulators of key osteoblastogenic genes, was altered in hind limb buds of embryos exposed to 5-AZA. Furthermore, the expression of receptor activator of nuclear factor kappa B ligand (RANKL) in femoral stromal/osteoblastic cells of 5-month-old offspring of 5-AZA-treated females was found to be increased. Collectively, this study implies for the first time that single low-dose exposure to a teratogen can induce bone loss in adult offspring, possibly via alteration of embryonic microRNAs and RANKL expression.

Evolution of vertebrate interferon inducible transmembrane proteins

BACKGROUND

Interferon inducible transmembrane proteins (IFITMs) have diverse roles, including the control of cell proliferation, promotion of homotypic cell adhesion, protection against viral infection, promotion of bone matrix maturation and mineralisation, and mediating germ cell development. Most IFITMs have been well characterised in human and mouse but little published data exists for other animals. This study characterised IFITMs in two distantly related marsupial species, the Australian tammar wallaby and the South American grey short-tailed opossum, and analysed the phylogeny of the IFITM family in vertebrates.

RESULTS

Five IFITM paralogues were identified in both the tammar and opossum. As in eutherians, most marsupial IFITM genes exist within a cluster, contain two exons and encode proteins with two transmembrane domains. Only two IFITM genes, IFITM5 and IFITM10, have orthologues in both marsupials and eutherians. IFITM5 arose in bony fish and IFITM10 in tetrapods. The bone-specific expression of IFITM5 appears to be restricted to therian mammals, suggesting that its specialised role in bone production is a recent adaptation specific to mammals. IFITM10 is the most highly conserved IFITM, sharing at least 85% amino acid identity between birds, reptiles and mammals and suggesting an important role for this presently uncharacterised protein.

CONCLUSIONS

Like eutherians, marsupials also have multiple IFITM genes that exist in a gene cluster. The differing expression patterns for many of the paralogues, together with poor sequence conservation between species, suggests that IFITM genes have acquired many different roles during vertebrate evolution.

Investigation of mitochondrial dysfunction by sequential microplate-based respiration measurements from intact and permeabilized neurons

Mitochondrial dysfunction is a component of many neurodegenerative conditions. Measurement of oxygen consumption from intact neurons enables evaluation of mitochondrial bioenergetics under conditions that are more physiologically realistic compared to isolated mitochondria. However, mechanistic analysis of mitochondrial function in cells is complicated by changing energy demands and lack of substrate control. Here we describe a technique for sequentially measuring respiration from intact and saponin-permeabilized cortical neurons on single microplates. This technique allows control of substrates to individual electron transport chain complexes following permeabilization, as well as side-by-side comparisons to intact cells. To illustrate the utility of the technique, we demonstrate that inhibition of respiration by the drug KB-R7943 in intact neurons is relieved by delivery of the complex II substrate succinate, but not by complex I substrates, via acute saponin permeabilization. In contrast, methyl succinate, a putative cell permeable complex II substrate, failed to rescue respiration in intact neurons and was a poor complex II substrate in permeabilized cells. Sequential measurements of intact and permeabilized cell respiration should be particularly useful for evaluating indirect mitochondrial toxicity due to drugs or cellular signaling events which cannot be readily studied using isolated mitochondria.

Insulin increases epiblast cell number of in vitro cultured mouse embryos via the PI3K/GSK3/p53 pathway

High-quality embryos give rise to embryonic stem cells (ESCs) at greater efficiencies than poor-quality embryos. However, most embryos available for human ESC derivation are of a reduced quality as a result of culture in relatively simple media up to 10 years earlier, before cryopreservation, or before compaction. In the present study, we used a mouse model to determine whether a culture with insulin from the 8-cell stage could increase the number of ESC progenitor epiblast cells in blastocysts, as well as endeavor to determine the molecular mechanism of the insulin's effect. Culture in media containing 1.7 ρM insulin increased epiblast cell number (determined by Oct4 and Nanog co-expression), and proportion in day 6 blastocysts. The inhibition of phosphoinositide 3 kinase (PI3K) (via LY294002), an early second messenger of the insulin receptor, blocked this effect. The inhibition of glycogen synthase kinase 3 (GSK3) or p53, 2 s messengers inactivated by insulin signaling (via CT99021 or pifithrin-α, respectively), increased epiblast cell numbers. When active, GSK3 and p53 block the transcription of Nanog, which is important for maintaining pluripotency. A simultaneous inhibition of GSK3 and p53 had no synergistic effects on epiblast cell number. The induced activation of GSK3 and p53, via the inhibition of proteins responsible for their inactivation (PKA via H-89 and SIRT-1 via nicotinamide, respectively), blocked the insulin's effect on the epiblast.From our findings, we conclude that insulin increases epiblast cell number via the activation of PI3K, which ultimately inactivates GSK3 and p53. Furthermore, we suggest that the inclusion of insulin in culture media could be used as a strategy for increasing the efficiency with which the ESC lines can be derived from cultured embryos.

Re-assessing K15 as an epidermal stem cell marker

The intermediate filament keratin 15 (K15) is present in variable amounts in various stratified epithelia, but has also been reported to be a stem cell marker in the hair follicle. Using peptide specific antibodies, we evaluated the temporal and spatial distribution pattern of K15 expression/localization during normal epidermal development and initiation of hair follicle formation, and in the injured mature epidermis (e.g., during acute injury and repair and in tumorigenesis). During development, K15 expression is first localized to a subset of epidermal basal cells and the overlying periderm at E12.5, but its expression is seen throughout the basal layer by E15.5 and beyond. In hair follicle morphogenesis, initial peg formation occurs in a K15-null area at E14.5 and as peg elongation proceeds through to the mature hair follicle, K15 expression follows the leading edge with positive cells restricted to the outer root sheath. In an epidermal injury model, K15 is first up-regulated and associated with both the basal and suprabasal layers of the interfollicular epidermis then expression becomes sporadic and down-regulated before a basal layer-specific association is re-established in the repaired epidermis. During tumorigenesis, K15 is first mis-expressed, and is ultimately down-regulated. Our data suggest that K15 protein expression may reflect not only expression in a stem or progenitor cell subpopulation, but also reflects the activity and responsiveness of basal-like cells to loss of homeostasis of the epidermal differentiation program. Thus, the data suggest caution in using K15 alone to delineate epidermal stem cells, and underscore the need for further investigation of K15 and other markers in epidermal cell subpopulations.

[Cyto B dependent and ouabain insensitive regulatory volume decrease in bicellular mouse embryo]

Mouse single-cell embryos exhibit robust Regulatory Volume Decrease (RVD). In what manner the very early mammalian embryo following zygote stage is appreciably altered by the anisotonic extracellular solution is, as yet, totally unclear. Little attention was paid to this direction since there was no way to determine the blastomere volume. This work has served to quantitatively investigate the osmotic response of bicellular mouse embryos employing Laser Scanning Microtomography (LSM) followed with three-dimensional reconstruction (3 DR). We have shown that bicellular mouse embryos in hypotonic Dulbecco's experience RVD. Embryonic cells subjected to hyposmolar exhibit rapid osmotic swelling followed by gradual shrinking back toward their original volume. The van't Hoff law defines swelling phase with the effective hydraulic conductivity of 0.3 micron x min(-1) x atm(-1). Water release during RVD in bicellular mouse embryos is abolished by Cytochalasin B (Cyto B) and the volume recovery is insensitive to ouabain treatment.

Genotoxic and cytotoxic study of Tecoma stans Bignoniaceae

Tecoma stans (Bignoniaceae) is a central and south American tree used for the control of diabetes. This plant is cultivated in Iraq. The dried leaves were soaked in ethanol and water separately for 3 days then filtered and dried. The genotoxic potential of Tecoma stans was studied by in vivo and in vitro system. This study examined the genotoxic activity of aqueous and ethanolic extracts on bone marrow cells from BALB/c mice through evaluation of mitotic index and chromosomal aberrations and cytotoxic effect of the two extracts on Mouse Embryo Fibroblast (MEF) cell line. No alteration in the total number of chromosomal aberrations or the number of cells with chromosomal aberrations observed and percentage of mitotic index at the concentrations tested remained unchanged. The higher concentrations used of the plant extracts had a cytotoxic effect on the MEF cell line. Both extracts had no significant clastogenic effect in vivo but showed cytotoxic effects on mouse embryo in vitro, caution should be exercised in the use of this substance as a medicine.

Rodent whole embryo culture

The direct effects of chemical exposures, environmental extremes, and nutrient quality/quantity have been very difficult to study in mammalian embryos due to their anatomical inaccessibility, paucity of tissues, and other factors such as real ethical concerns in human studies. Many acute and chronic developmental anomalies can trace their origins to postimplantation phases of gestation where the organs are first being established and growth and differentiation are in highly active states of flux. Most agents and conditions that produce birth defects are believed to act during this period of organogenesis. The evolution of rodent whole embryo culture (WEC) techniques has provided a valuable experimental model where physiological conditions and exposures can be carefully controlled and manipulated to test hypotheses and explore biochemical and molecular mechanisms of action. Exposure to chemical agents can be controlled through their direct addition to the culture medium. Optimal in vitro culture conditions support the growth of intact, viable conceptuses (embryo and associated extraembryonic membranes) from early egg cylinder stages through establishment of the neural plate, gastrulation, neural tube closure, onset of active heartbeat and circulation, and the initial formation of all major organ systems that occur prior to the establishment of a functional placenta. Detailed comparisons of in vivo and in vitro growth show that conceptuses grown in WEC are nearly identical, structurally and functionally, to conceptuses of the same developmental stage that are allowed to develop normally in vivo. Culture conditions and mechanical apparatus can be modified to suit a large number of different experimental approaches and paradigms.

Culture systems: embryo culture and monozygotic twinning

The incidence of monozygotic twinning in pregnancies achieved with assisted reproductive technologies (ART) is significantly higher than spontaneously conceived pregnancies. The factors associated with ART that predispose the embryos to splitting are not well-characterized. Assisted hatching and extended embryo culture are two ART laboratory methods that have been risk factors for monozygotic twinning. The methods and strategies that may be employed to avoid monozygotic twinning are discussed in this chapter.

Epigenetic approaches and methods in developmental toxicology: role of HDAC inhibition in teratogenic events

The relevance of histone acetylation/deacetylation in regulating decompaction/compaction of chromatin and, consequently, in regulating gene expression, has been described for many physiological and pathological biological processes, including normal and altered embryo development. Similarly to other biological systems, also in embryo cells the acetylation status is controlled by the antagonist activity of histone acetyl transferases (HATs) and histone deacetylases (HDACs) and is influenced by other factors acting on chromatin structure (i.e., every epigenetic modification of chromatin). The relevance of acetylation during development has been demonstrated in all developmental phases, from gametogenesis to zygote formation and during early and late embryonic stages. Moreover, the increase number of xenobiotic showing HDAC inhibitory activity recently focused the attention of teratologists on the possible role of HDAC inhibition as a novel teratogenic mechanism. This hypothesis has been demonstrated at least in embryos at somitogenic stages (for mouse embryos from stage E8 till stage E15): HDAC inhibition, histone hyperacetylation, increased cell death (apoptosis) has been suggested as the main event cascade involved in axial skeletal defects induced in rodent by a number of HDAC inhibitors, including the antiepileptic drug valproic acid.

Rabbit whole embryo culture

Although the rabbit is used extensively in developmental toxicity testing, relatively little is known about the fundamental developmental biology of this species let alone mechanisms underlying developmental toxicity. This paucity of information about the rabbit is partly due to the historic lack of whole embryo culture (WEC) methods for the rabbit, which have only been made available fairly recently. In rabbit WEC, early somite stage embryos (gestation day 9) enclosed within an intact amnion and attached to the visceral yolk sac are dissected from maternal tissues and placed in culture for up to 48 h at approximately 37°C and are continuously exposed to an humidified gas atmosphere mixture in a rotating culture system. During this 48 h culture period, major phases of organogenesis can be studied including cardiac looping and segmentation, neural tube closure, and development of anlagen of the otic system, eyes and craniofacial structures, somites and early phases of limb development (up to bud stage), as well as expansion and closure of the visceral yolk sac around the embryo. Following completion of the culture period, embryos are evaluated based on several growth and development parameters and also are assessed for morphological abnormalities. The ability to sustain embryo development independent of the maternal system allows for exposure at precise development stages providing the opportunity study the direct action of a teratogen or one of its metabolites on the developing embryo. Rabbit WEC is perhaps most useful when used in conjunction with rodent WEC methods to investigate species-specific mechanisms of developmental toxicity.

[The separate and combined effects of calcium pantothenate deficiency and cadmium intoxication on rat reproductive function]

The publication presents investigation evaluated of separate and combined effects of calcium pantothenate deficiency and cadmium (Cd2+) intoxication on rat reproductive function. The experi-ments were performed on 280 adult and 890 offspring of Wistar rats. Reproductive function was estimated by fertility study, prenatal and postnatal development of offspring. The separate and combined effects of and cadmium intoxication during the mating period and pregnancy had no effect on fertility and fecundity of rats, pre-and postimplantation loss, the survival of offspring, and not caused the abnormal development of skeleton and internal organs. However, in prenatal ontogeny of this effect was manifested by lower body weight and fetal growth, postnatal - underdevelopment of rat pups in all morphological and functional studied parameters and increasing number of stillbirths in the offspring.

Exposure of embryos to oxygen at low concentration in a cleavage stage transfer program: reproductive outcomes in a time-series analysis

BACKGROUND

Embryos are exposed to oxygen at a concentration of 2% to 8% under in vivo conditions. Laboratory culture of embryos with oxygen at atmospheric tension impairs embryo metabolism and blastocyst development in several species. Indeed, a high rate of live births after a day 5 transfer has been obtained by lowering oxygen concentration in the incubator atmosphere, thus definitively proving the damaging effect of oxygen at atmospheric tension on late stage development of human embryos. Conversely, the possible beneficial effect of low oxygen tension on assisted reproductive technology (ART) outcomes in a selective cleavage stage transfer program remains controversial. Therefore, the present study validated the hypothesis that oxygen at reduced concentration may improve ART outcomes when cleavage stage embryos are transferred.

METHODS

The effect of oxygen at atmospheric versus reduced concentration on laboratory and clinical outcomes of both in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycles were compared. Evaluation of outcomes included fertilization, cleavage, and implantation rates. Clinical outcomes were also assessed in our analysis.

RESULTS

From May 2010 to Mid-October 2010 357 ART cycles (ICSI n = 273 and IVF n = 84) were performed using atmospheric oxygen laboratory incubators while from Mid-October 2010 until March 2011 306 cycles (ICSI n = 224 and IVF n = 82) were carried out under low oxygen concentration. The multi-ovulation protocols were not significantly different between the two study periods. The medical and laboratory staff, the laboratory, and its procedures and the operating room did not differ between the two groups, neither did the culture media. For ICSI procedures, no significant difference in ART outcomes was found between the two culture conditions. For conventional IVF cycles, both fertilization rate (59 +/- 36 vs. 71 +/- 32, respectively) and proportion of embryos obtained (38% vs. 50%, respectively) were significantly improved under low oxygen condition.

CONCLUSIONS

Culture of embryos in oxygen at low tension improved ART outcomes during a selective cleavage stage transfer program.

Assessment of xenobiotic biotransformation including reactive oxygen species generation in the embryo using benzene as an example

Quantification of embryonic metabolic capacity is an important tool in developmental toxicology research. Bioactivation of xenobiotics into reactive intermediates often contributes to embryo toxicity; thus, identification and quantification of these toxic metabolites is essential to gain further understanding of developmental toxicity. This chapter uses the environmental chemical benzene as a model xenobiotic to describe the detection of both metabolites and reactive oxygen species (ROS) in fetal liver. Briefly, mice are bred and the presence of a vaginal plug in a female mouse indicates gestational day 1. On the desired gestational day, pregnant dams are exposed to benzene followed by sacrifice at the desired time-point after exposure. Using gas chromatography coupled to mass spectrometry, the detection of benzene metabolites can be achieved. Additionally, we describe the measurement of ROS by flow cytometry using the fluorescent probe 5-(and-6)-chloromethyl-2',7'-dichlorofluorescein diacetate, which readily diffuses into cells and, upon oxidation by any ROS, is converted to the highly fluorescent, negatively charged carboxydichlorofluorescein, which remains trapped within the cells.

The effect of nanoparticles in rats during critical periods of pregnancy

BACKGROUND AND OBJECTIVE. Nanotechnology works with substances at a nanometer scale, and it offers many solutions for biomedicine. Nanoparticles (NPs) have been shown as effective agents for imaging, drug delivery, pathogen detection, etc. However, to date, NP toxicity is poorly known. The aim of our study was to investigate the embryotoxicity and teratogenicity of quantum dots (QDs) at the different stages of rat embryogenesis. MATERIALS AND METHODS. Wistar rats were injected with CdSe/ZnS or CdTe QDs on the 6th, 13th, and 18th days of embryogenesis. Cyclophosphamide was chosen as a positive control of embryotoxicity. On the 21st day, the number of resorptions, weight, length, and external malformations of the embryos were estimated. Fluorescence spectroscopy and microscopy analysis were used to determine the accumulation of QDs in the tissues. RESULTS. Exposure to cyclophosphamide during the pregnancy decreased the embryonic weight and length when compared with the control group and produced numerous malformations. The effects depended on the stage of embryogenesis. Meanwhile, QDs did not cause any embryotoxic or teratogenic effects. However, CdTe QDs induced necrosis in the tissues of the peritoneal cavity. The necrotic tissues contained QDs with altered spectroscopic properties. Spectroscopic and microscopic tissue examination revealed that QDs accumulated in the placenta, but no penetration to the embryonic tissues was observed. CONCLUSIONS. QDs did not cause any direct embryotoxic or teratogenic effects, but they had adverse effects on the maternal organism. The observed QD effects and the long-term accumulation of QDs in the maternal organism may increase the risk of adverse effects on embryo development.

Generation of glucose-responsive functional islets with a three-dimensional structure from mouse fetal pancreatic cells and iPS cells in vitro

Islets of Langerhans are a pancreatic endocrine compartment consisting of insulin-producing β cells together with several other hormone-producing cells. While some insulin-producing cells or immature pancreatic cells have been generated in vitro from ES and iPS cells, islets with proper functions and a three-dimensional (3D) structure have never been successfully produced. To test whether islets can be formed in vitro, we first examined the potential of mouse fetal pancreatic cells. We found that E16.5 pancreatic cells, just before forming islets, were able to develop cell aggregates consisting of β cells surrounded by glucagon-producing α cells, a structure similar to murine adult islets. Moreover, the transplantation of these cells improved blood glucose levels in hyperglycemic mice. These results indicate that functional islets are formed in vitro from fetal pancreatic cells at a specific developmental stage. By adopting these culture conditions to the differentiation of mouse iPS cells, we developed a two-step system to generate islets, i.e. immature pancreatic cells were first produced from iPS cells, and then transferred to culture conditions that allowed the formation of islets from fetal pancreatic cells. The islets exhibited distinct 3D structural features similar to adult pancreatic islets and secreted insulin in response to glucose concentrations. Transplantation of the islets improved blood glucose levels in hyperglycemic mice. In conclusion, the two-step culture system allows the generation of functional islets with a 3D structure from iPS cells.

Dermatan sulfotransferase Chst14/D4st1, but not chondroitin sulfotransferase Chst11/C4st1, regulates proliferation and neurogenesis of neural progenitor cells

Chondroitin sulfates (CSs) and dermatan sulfates (DSs) are enriched in the microenvironment of neural stem cells (NSCs) during development and in the adult neurogenic niche, and have been implicated in mechanisms governing neural precursor migration, proliferation and differentiation. In contrast to previous studies, in which a chondroitinaseABC-dependent unselective deglycosylation of both CSs and DSs was performed, we used chondroitin 4-O-sulfotransferase-1 (Chst11/C4st1)- and dermatan 4-O-sulfotransferase-1 (Chst14/D4st1)-deficient NSCs specific for CSs and DSs, respectively, to investigate the involvement of specific sulfation profiles of CS and DS chains, and thus the potentially distinct roles of CSs and DSs in NSC biology. In comparison to wild-type controls, deficiency for Chst14 resulted in decreased neurogenesis and diminished proliferation of NSCs accompanied by increased expression of GLAST and decreased expression of Mash-1, and an upregulation of the expression of the receptors for fibroblast growth factor-2 (FGF-2) and epidermal growth factor (EGF). By contrast, deficiency in Chst11 did not influence NSC proliferation, migration or differentiation. These observations indicate for the first time that CSs and DSs play distinct roles in the self-renewal and differentiation of NSCs.

Abnormal notochord branching is associated with foregut malformations in the adriamycin treated mouse model

Oesophageal atresia (OA) and tracheooesophageal fistula (TOF) are relatively common human congenital malformations of the foregut where the oesophagus does not connect with the stomach and there is an abnormal connection between the stomach and the respiratory tract. They require immediate corrective surgery and have an impact on the future health of the individual. These abnormalities are mimicked by exposure of rat and mouse embryos in utero to the drug adriamycin. The causes of OA/TOF during human development are not known, however a number of mouse mutants where different signalling pathways are directly affected, show similar abnormalities, implicating multiple and complex signalling mechanisms. The similarities in developmental outcome seen in human infants and in the adriamycin treated mouse model underline the potential of this model to unravel the early embryological events and further our understanding of the processes disturbed, leading to such abnormalities. Here we report a systematic study of the foregut and adjacent tissues in embryos treated with adriamycin at E7 and E8 and analysed between E9 and E12, comparing morphology in 3D in 149 specimens. We describe a spectrum of 8 defects, the most common of which is ventral displacement and branching of the notochord (in 94% of embryos at E10) and a close spatial correspondence between the site of notochord branching and defects of the foregut. In addition gene expression analysis shows altered dorso-ventral foregut patterning in the vicinity of notochord branches. This study shows a number of features of the adriamycin mouse model not previously reported, implicates the notochord as a primary site of disturbance in such abnormalities and underlines the importance of the model to further address the mechanistic basis of foregut congenital abnormalities.

Derivation, characterization, and stable transfection of induced pluripotent stem cells from Fischer344 rats

The rat represents an important animal model that, in many respects, is superior to the mouse for dissecting behavioral, cardiovascular and other physiological pathologies relevant to humans. Derivation of induced pluripotent stem cells from rats (riPS) opens the opportunity for gene targeting in specific rat strains, as well as for the development of new protocols for the treatment of different degenerative diseases. Here, we report an improved lentivirus-based hit-and-run riPS derivation protocol that makes use of small inhibitors of MEK and GSK3. We demonstrate that the excision of proviruses does not affect either the karyotype or the differentiation ability of these cells. We show that the established riPS cells are readily amenable to genetic manipulations such as stable electroporation. Finally, we propose a genetic tool for an improvement of riPS cell quality in culture. These data may prompt iPS cell-based gene targeting in rat as well as the development of iPS cell-based therapies using disease models established in this species.

Specific control of pancreatic endocrine β- and δ-cell mass by class IIa histone deacetylases HDAC4, HDAC5, and HDAC9

OBJECTIVE

Class IIa histone deacetylases (HDACs) belong to a large family of enzymes involved in protein deacetylation and play a role in regulating gene expression and cell differentiation. Previously, we showed that HDAC inhibitors modify the timing and determination of pancreatic cell fate. The aim of this study was to determine the role of class IIa HDACs in pancreas development.

RESEARCH DESIGN AND METHODS

We took a genetic approach and analyzed the pancreatic phenotype of mice lacking HDAC4, -5, and -9. We also developed a novel method of lentiviral infection of pancreatic explants and performed gain-of-function experiments.

RESULTS

We show that class IIa HDAC4, -5, and -9 have an unexpected restricted expression in the endocrine β- and δ-cells of the pancreas. Analyses of the pancreas of class IIa HDAC mutant mice revealed an increased pool of insulin-producing β-cells in Hdac5(-/-) and Hdac9(-/-) mice and an increased pool of somatostatin-producing δ-cells in Hdac4(-/-) and Hdac5(-/-) mice. Conversely, HDAC4 and HDAC5 overexpression showed a decreased pool of insulin-producing β-cells and somatostatin-producing δ-cells. Finally, treatment of pancreatic explants with the selective class IIa HDAC inhibitor MC1568 enhances expression of Pax4, a key factor required for proper β-and δ-cell differentiation and amplifies endocrine β- and δ-cells.

CONCLUSIONS

We conclude that HDAC4, -5, and -9 are key regulators to control the pancreatic β/δ-cell lineage. These results highlight the epigenetic mechanisms underlying the regulation of endocrine cell development and suggest new strategies for β-cell differentiation-based therapies.

[Study on mutagenicity and teratogenicity of ammonium dinitramide]

OBJECTIVE

To study the mutagenicity and teratogenicity induced by ammonium dinitramide(ADN).

METHODS

According to technical specifications for toxicity determination of chemicals, Salmonella typhimurium reverse mutation assay (Ames assay), in vivo mammalian erythrocyte micronucleus test, sperm malformation test and teratogenesis test were used to detect the mutagenicity and teratogenicity induced by AND.

RESULTS

When the exposure doses of AND were 8-5000 pg/plate, the result of Ames assay was negative. As compared with control group, the micronucleus rate of mice exposed to 113.8 mg/kg AND significantly increased(P<0.05), the sperm malformation rates of mice exposed to 54.4-272.0 mg/kg AND did not increased significantly. The survival rate of fetuses decreased, the rate of assimilated fetuses increased, the rate of fetus sternum agenesis enhanced in mice exposed to 319 mg/kg AND, as compared with controls. The rates of in the 4th-6th fetus sternum agenesis in groups exposed to 21.3, 79.7 and 319 mg/kg AND were higher than that in control group. The malformation rate of fetus bowels in groups exposed to 319 mg/kg AND was higher than that in control group. The teratogenic index of ADN was 30.

CONCLUSION

AND may be a mutagen and induce the teratogenic effect.

Reproductive toxicity of Rhizoma Sparganii (Sparganium stoloniferum Buch.-Ham.) in mice: mechanisms of anti-angiogenesis and anti-estrogen pharmacologic activities

ETHNOPHARMACOLOGICAL RELEVANCE

Indications and preliminary studies of Rhizoma Sparganii (RS) suggest its pharmacological mechanism is involved with endocrine/angiogenesis functions. We therefore studied its potential toxicity on reproduction in mice.

MATERIALS AND METHODS

Reproductive toxicity of 100, 200 and 400 mg/kg RS extract were studied in pregnant ICR mice and its offspring. The embryos' fibroblast growth factor-1 (FGF-1), vascular endothelial growth factor (VEGF) and estrogen receptor-α (ER-α) were evaluated as targets of endocrine/angiogenesis by immunohistochemical test.

RESULTS

The offspring of treated mice (100, 200 and 400 mg/kg RS extract) during their pregnancy had various pathological conditions, suggesting an abnormal FGF signaling phenomenon during pregnancy. Embryos from the 400 mg/kg group had significantly depressed levels of FGF-1 (P < 0.01) and VEGF (P < 0.05) expression levels as compared to controls by immunohistochemical test. Dysplasia in the heart (12.9%), craniofacial region (18.3%) and vertebrae (32.5%) presented in embryos of the 400 mg/kg group. Furthermore, the ER-α expression was inversely proportional to FGF-1 levels in the same embryo (P < 0.01).

CONCLUSIONS

These results implicate a FGF signaling abnormality in vivo and indicate that RS has anti-angiogenesis and anti-estrogen toxicity effects in pregnant rodents.

Pancreatic mesenchyme regulates epithelial organogenesis throughout development

Genetic disruption of the pancreatic mesenchyme reveals that it is critical for the expansion of epithelial progenitors and for the proliferation of insulin-producing beta cells.

The developing pancreatic epithelium gives rise to all endocrine and exocrine cells of the mature organ. During organogenesis, the epithelial cells receive essential signals from the overlying mesenchyme. Previous studies, focusing on ex vivo tissue explants or complete knockout mice, have identified an important role for the mesenchyme in regulating the expansion of progenitor cells in the early pancreas epithelium. However, due to the lack of genetic tools directing expression specifically to the mesenchyme, the potential roles of this supporting tissue in vivo, especially in guiding later stages of pancreas organogenesis, have not been elucidated. We employed transgenic tools and fetal surgical techniques to ablate mesenchyme via Cre-mediated mesenchymal expression of Diphtheria Toxin (DT) at the onset of pancreas formation, and at later developmental stages via in utero injection of DT into transgenic mice expressing the Diphtheria Toxin receptor (DTR) in this tissue. Our results demonstrate that mesenchymal cells regulate pancreatic growth and branching at both early and late developmental stages by supporting proliferation of precursors and differentiated cells, respectively. Interestingly, while cell differentiation was not affected, the expansion of both the endocrine and exocrine compartments was equally impaired. To further elucidate signals required for mesenchymal cell function, we eliminated β-catenin signaling and determined that it is a critical pathway in regulating mesenchyme survival and growth. Our study presents the first in vivo evidence that the embryonic mesenchyme provides critical signals to the epithelium throughout pancreas organogenesis. The findings are novel and relevant as they indicate a critical role for the mesenchyme during late expansion of endocrine and exocrine compartments. In addition, our results provide a molecular mechanism for mesenchymal expansion and survival by identifying β-catenin signaling as an essential mediator of this process. These results have implications for developing strategies to expand pancreas progenitors and β-cells for clinical transplantation.

Embryonic development is a highly complex process that requires tight orchestration of cellular proliferation, differentiation, and migration as cells grow within loosely aggregated mesenchyme and more organized epithelial sheets to form organs and tissues. In addition to intrinsic cell-autonomous signals, these events are further regulated by environmental cues provided by neighboring cells. Prior work demonstrated a critical role for the surrounding mesenchyme in guiding epithelial growth during the early stages of pancreas development. However, it remained unclear whether the mesenchyme also guided the later stages of pancreas organogenesis when the functional exocrine and endocrine cells are formed. Here, we show that specific genetic ablation of the mesenchyme at distinct developmental stages in vivo results in the formation of a smaller, misshapen pancreas. Loss of the mesenchyme profoundly impairs the expansion of both endocrine and exocrine pancreatic progenitors, as well as the proliferative capacity of maturing cells, including insulin-producing beta-cells. Thus, our studies reveal unappreciated roles for the mesenchyme in guiding the formation of the epithelial pancreas throughout development. The results suggest that identifying the specific mesenchymal signals might help to optimize cell culture protocols that aim to achieve the differentiation of stem cells into insulin-producing beta cells.

Serum unconjugated bisphenol A concentrations in men may influence embryo quality indicators during in vitro fertilization

Here we assess bisphenol A (BPA) in couples undergoing in vitro fertilization (IVF) and indicators of embryo quality; embryo cell number (ECN) and embryo fragmentation score (EFS). Twenty-seven couples provided serum on the day of oocyte retrieval. Unconjugated BPA was measured by HPLC with Coularray detection. Odds ratios (OR) were generated using ordinal logistic regression including female and male BPA concentrations, age and race, and day of embryo transfer for ECN. Inverse associations are suggested for male BPA with ECN (OR=0.70, P=0.069), and EFS (OR=0.54, P=0.009), but not for women. Male BPA exposure may affect embryo quality during IVF.

[Association of genotoxic and teratogenic effects induced by cyclophosphamide and their modification with afobazole]

Intact rat embryonic and placental tissues were found to have a characteristic ratio of cells with different degrees of DNA fragmentation. The genotoxic effect of cyclophosphamide was shown to be accompanied by a quantitative deviation from the control group established ratio of different cell types. A relationship was found between the abnormal ratio of different cell types in the embryonic and placental tissues and the occurrence of embryonic morphological abnormalities. The antimutagen afobazole (1, 10, and 100 mg/kg) was ascertained to be able to lower genotoxic effects in the embryonic and placental tissues and their related malformations. It is presumed that it is promising to use DNA damage index in the embryonic and placental cells as a biomarker of the course of embryogenesis and as a basis for devising an indicator test for rapid screening of potential teratogens.

A positive role of cadherin in Wnt/β-catenin signalling during epithelial-mesenchymal transition

The Wnt/β-catenin signalling pathway shares a key component, β-catenin, with the cadherin-based adhesion system. The signalling function of β-catenin is conferred by a soluble cytoplasmic pool that is unstable in the absence of a Wnt signal, whilst the adhesion function is based on a cadherin-bound, stable pool at the membrane. The cadherin complex is dynamic, allowing for cell-cell rearrangements such as epithelial-mesenchymal transition (EMT), where the complex turns over through internalisation. Potential interplay between the two pools remains poorly understood, but cadherins are generally considered negative regulators of Wnt signalling because they sequester cytoplasmic β-catenin. Here we explore how cellular changes at EMT affect the signalling capacity of β-catenin using two models of EMT: hepatocyte growth factor (HGF) treatment of MDCK cells, and gastrulation in embryonic development. We show that EMT not only provides a pool of signalling-competent β-catenin following internalisation of cadherin, but also significantly facilitates activation of the Wnt pathway in response to both Wnt signals and exogenous β-catenin. We further demonstrate that availability of β-catenin in the cytoplasm does not necessarily correlate with Wnt/β-catenin pathway activity, since blocking endocytosis or depleting endogenous cadherin abolishes pathway activation despite the presence of β-catenin in the cytoplasm. Lastly we present data suggesting that cadherins are required for augmented activation of the Wnt/β-catenin pathway in vivo. This suggests that cadherins play a crucial role in β-catenin-dependent transcription.

A pragmatic RCT of conventional versus increased concentration sucrose in freezing and thawing solutions for human embryos

BACKGROUND

Intact frozen-thawed embryos have a greater potential than damaged embryos to establish successful pregnancies. This study aimed to determine whether elevated concentrations of sucrose during freezing would increase the proportion of patients with ≥ 50% of embryos intact after thawing (primary outcome), and improve clinical outcome.

METHODS

In a two arm, parallel group, pragmatic trial, IVF/ICSI couples were randomized prospectively to have their supernumerary embryos frozen in a medium containing 0.1 M sucrose (control; n = 99) or 0.3 M sucrose (intervention; n = 102).

RESULTS

More control (74/99) than intervention (63/102) couples had at least one embryo thawed (P = 0.07). Significantly more (P = 0.005) intervention (53/63) than control (45/74) couples had ≥ 50% of embryos intact. Freezing in a medium containing 0.3 M sucrose increased by 3.4-fold [95% confidence interval (CI) (1.45, 7.82)] the likelihood of a couple having ≥ 50% of their embryos intact. In the fresh cycle, live birth rate per transfer was similar in the control (35/95) and intervention (36/93) groups (P = 0.91). More control (19/63) than intervention (9/59) couples had a live birth after frozen embryo transfer (P = 0.08). When fresh and frozen cycles were combined, fewer intervention (n = 102) than control (n = 99) couples had at least one live birth (42 versus 53%). The difference in cumulative live birth rate was not significant [hazard ratio = 0.75, 95% CI (0.49, 1.13); P = 0.17].

CONCLUSIONS

Increasing the concentration of sucrose in the freezing medium improves embryo survival, but this is not reflected by increased cumulative birth rates.

CLINICAL TRIALS REGISTRATION NUMBER

ISRCTN93314892.

The collagen chaperone HSP47 is a new interactor of APP that affects the levels of extracellular beta-amyloid peptides

Alzheimer disease (AD) is a neurodegenerative disorder characterized by progressive decline of cognitive function that represents one of the most dramatic medical challenges for the aging population. Aβ peptides, generated by processing of the Amyloid Precursor Protein (APP), are thought to play a central role in the pathogenesis of AD. However, the network of physical and functional interactions that may affect their production and deposition is still poorly understood. The use of a bioinformatic approach based on human/mouse conserved coexpression allowed us to identify a group of genes that display an expression profile strongly correlated with APP. Among the most prominent candidates, we investigated whether the collagen chaperone HSP47 could be functionally correlated with APP. We found that HSP47 accumulates in amyloid deposits of two different mouse models and of some AD patients, is capable to physically interact with APP and can be relocalized by APP overexpression. Notably, we found that it is possible to reduce the levels of secreted Aβ peptides by reducing the expression of HSP47 or by interfering with its activity via chemical inhibitors. Our data unveil HSP47 as a new functional interactor of APP and imply it as a potential target for preventing the formation and/or growth amyloid plaques.

Melatonin improves the oocyte and the embryo in IVF patients with sleep disturbances, but does not improve the sleeping problems

PURPOSE

We aimed to analyse the in vitro fertilization-embryo transfer (IVF-ET) outcomes of the patients with sleep disturbances who were administered melatonin.

METHODS

A total of 60 patients with sleep disturbances were divided into two groups. The study group (group A, n=30) had underwent the IVF-ET with melatonin administration and the control group (group B, n=30) without melatonin. Sleeping status after melatonin administration and the IVF outcomes were compared between the two groups.

RESULTS

Sleeping status change was not significant (p>0.05). The mean number of the retrieved oocytes, the mean MII oocyte counts, the G1 embryo ratio were significantly higher in the melatonin administered group (group A) than that the non-administered group (group B); p=0.0001; p=0.0001; p<0.05 respectively.

CONCLUSION

IVF patients with sleep disorders may benefit from melatonin administration in improving the oocyte and the embryo quality, but the sleeping problem itself may not be fixed.

[Developmental toxicity of retrorsine on mouse embryos in vitro]

OBJECTIVE

To investigate the fetotoxicity of retrorsine.

METHOD

Mouse whole embryo culture (WEC) was applied. Post-implantation (8.5 d) mouse embryos were isolated from their mothers and put into the medium of immediately centrifuged serum (ICS) prepared from rats. Different concentrations of retrorsine (12.5, 25, 50, 100 mg x L(-1)) were added into the WEC culture. Development (yolk sac diameter, crown-rump length, head length, somite number) and organic morphodifferentiation (yolk sac circulation, allantois, embryonic flexion, heart, brain, optic-otic-olfactory organ, branchial arch, maxillary, mandible, bud) of embryos were observed at 48 h after treatment.

RESULT

Obvious fetotoxicity could be observed in various retrorsine treatment groups in a dose-dependent manner. Development of embryos was delayed significantly at dose 12.5-100 mg x L(-1). Malformations were shown in all organic morphodifferentiation indexes, especially in otic-olfactory organ, branchial arch, maxillary, mandible, bud.

CONCLUSION

Retrorsine had obvious fetotoxicity in vitro WEC culture, indicating that exposure of pregnant mice to retrorsine may have potential risk on fetals.

Neurotoxicity of brominated flame retardants: (in)direct effects of parent and hydroxylated polybrominated diphenyl ethers on the (developing) nervous system

BACKGROUND/OBJECTIVE

Polybrominated diphenyl ethers (PBDEs) and their hydroxylated (OH-) or methoxylated forms have been detected in humans. Because this raises concern about adverse effects on the developing brain, we reviewed the scientific literature on these mechanisms.

DATA SYNTHESIS

Many rodent studies reported behavioral changes after developmental, neonatal, or adult exposure to PBDEs, and other studies documented subtle structural and functional alterations in brains of PBDE-exposed animals. Functional effects have been observed on synaptic plasticity and the glutamate-nitric oxide-cyclic guanosine monophosphate pathway. In the brain, changes have been observed in the expression of genes and proteins involved in synapse and axon formation, neuronal morphology, cell migration, synaptic plasticity, ion channels, and vesicular neurotransmitter release. Cellular and molecular mechanisms include effects on neuronal viability 
(via apoptosis and oxidative stress), neuronal differentiation and migration, neurotransmitter release/uptake, neurotransmitter receptors and ion channels, calcium (Ca²⁺) homeostasis, and intracellular signaling pathways.

DISCUSSION

Bioactivation of PBDEs by hydroxylation has been observed for several endocrine end points. This has also been observed for mechanisms related to neurodevelopment, including binding to thyroid hormone receptors and transport proteins, disruption of Ca²⁺ homeostasis, and modulation of GABA and nicotinic acetylcholine receptor function.

CONCLUSIONS

The increased hazard for developmental neurotoxicity by hydroxylated (OH-)PBDEs compared with their parent congeners via direct neurotoxicity and thyroid disruption clearly warrants further investigation into a) the role of oxidative metabolism in producing active metabolites of PBDEs and their impact on brain development; b) concentrations of parent and OH-PBDEs in the brain; and c) interactions between different environmental contaminants during exposure to mixtures, which may increase neurotoxicity.