Gene Expression In Fetal Liver Research Articles

Biochemical and metabolic profiles in in vivo- and in vitro-derived concepti in cattle

The aim of this study was to compare metabolic profiles of maternal and fetal blood and liver gene expression patterns of Day-225 bovine fetuses produced either in vivo (IVD) by superovulation and artificial insemination, or in vitro by in vitro fertilization (IVF) or by Handmade Cloning (NT-HMC). Biochemical evaluations were performed in fetal and maternal plasma and the expression of key genes to fetal development were analyzed by RT-qPCR in fetal liver tissue. In addition to group comparisons, data were also used for correlation analyses with physical traits using simple correlation test and AN(C)OVA. Most fetal parameters related to liver and kidney functions and hemoglobin metabolism, and the osmolalities in fetal plasma and placental fluids were higher in clones than the other two groups. Glucose, fructose, triglycerides and VLDL concentrations in fetal plasma, concentration of fructose and total amount of glucose and fructose in the allantoic fluid were higher in clones. Differences in the relative gene expression in fetal liver were also detected for genes related to fructose and glucose metabolism, sugar transport, and fatty acid and cholesterol metabolism. In conclusion, important differences in the metabolism of cloned concepti were identified and suggest active fructose accumulation and lipid synthesis, which may be associated with metabolic fetal programming and excessive prenatal growth.

Maternal dietary protein restriction and excess affects offspring gene expression and methylation of non-SMC subunits of condensin I in liver and skeletal muscle

Recent evidence indicates that maternal nutrition during pregnancy influences gene expression in offspring through epigenetic alterations. In the present study we evaluated the effect of protein excess and deficiency during porcine pregnancy on offspring hepatic and skeletal muscular expression patterns of key genes of methionine metabolism (DNMT1, DNMT3a, DNMT3b, BHMT, MAT2B and AHCYL1), condensin I subunit genes (NCAPD2, NCAPG and NCAPH), important for chromosome condensation and segregation, global DNA methylation and gene-specific DNA methylation. German Landrace sows were randomly assigned to control (CO), high protein (HP) and low protein (LP) diet groups. Tissue samples of offspring were collected from fetal (dpc95), newborn (dpn1), weanling (dpn28) and finisher pigs (dpn188). Gene expression of DNMT1, DNMT3a and DNMT3b was influenced by both HP and LP diets, indicating an involvement of DNA methylation in fetal programming by maternal protein supply. Moreover, hepatic global methylation was significantly affected by protein restriction at dpc95 (p = 0.004) and by protein excess at dpn188 (p = 0.034). Gene expression in fetal liver was significantly different between CO and LP for NCAPD2 (p = 0.0005), NCAPG (p = 0.0009) and NCAPH (p < 0.0001). In skeletal muscle, LP fetuses had significantly altered gene expression of NCAPD2 (p = 0.020) and NCAPH (p = 0.001), compared with CO. Furthermore, NCAPG was differentially methylated among LP, HP and CO; indeed, a significant positive correlation was detected with transcript amount in fetal pigs (r = 0.47, p = 0.002). These data demonstrate that both restriction and excess dietary protein during pregnancy alters the offspring’s epigenetic marks and influences gene expression.

2,3,7,8-Tetrachlorodibenzo-P-Dioxin (TCDD) or Diethylstilbestrol (DES) Cause Similar Hematopoietic Hypocellularity and Hepatocellular Changes in Murine Fetal Liver, but Differentially Affect Gene Expression

TCDD and DES have immunotoxic effects, including selective diminution of T lymphocyte progenitors in the fetal liver. The histologic presentation of fetal liver after exposure to either chemical has not been described. Similarly, limited information exists regarding mechanisms by which TCDD or DES may alter fetal hematopoiesis. Treatment of pregnant C57BL/6 mice with either 10 micro g/kg/day TCDD or 48 micro g/kg/day DES on gestation days (gd) 14 and 16 led to increased fetal liver weight on gd 18. Moderate anisocytosis and anisokaryosis with increased cytoplasmic and nuclear sizes, and increased cytoplasmic basophilia were present within hepatocytes after TCDD or DES. Both chemicals also decreased the presence of hematopoietic cells, however megakaryocyte numbers were unaffected. In contrast to these similar outcomes, real time quantitative PCR using a preliminary panel of 4 genes suggested that the chemicals act through different gene targets. TCDD increased c-jun gene expression in fetal liver, and decreased p53 without alteration in bcl-2 expression, indicating possible pro-proliferative and antiapoptotic effects. DES decreased c-jun and bcl-2, without altering p53, suggesting a shift away from proliferation. Both agents decreased PKCalpha expression, which may suggest shared decreased phosphorylation of substrates required for normal cell cycle progression.

Imprinted gene expression in the rat embryo–fetal axis is altered in response to periconceptional maternal low protein diet

In our previous study, we have shown that maternal low protein diet (LPD, 9% casein vs 18% casein control) fed exclusively during the rat preimplantation period (0-4.25 day postcoitum) induced low birth weight, altered postnatal growth and hypertension in a gender-specific manner. In this study, we investigated the effect of maternal LPD restricted only to the preimplantation period (switched diet) or provided throughout gestation on fetal growth and imprinted gene expression in blastocyst and fetal stages of development. Male, but not female, blastocysts collected from LPD dams displayed a significant reduction (30%) in H19 mRNA level. A significant reduction in H19 (9.4%) and Igf2 (10.9%) mRNA was also observed in male, but not in female, fetal liver at day 20 postcoitum in response to maternal LPD restricted to the preimplantation period. No effect on the blastocyst expression of Igf2R was observed in relation to maternal diet. The reduction in H19 mRNA expression did not correlate with an observed alteration in DNA methylation at the H19 differentially methylated region in fetal liver. In contrast, maternal LPD throughout 20 days of gestation did not affect male or female H19 and Igf2 imprinted gene expression in fetal liver. Neither LPD nor switched diet treatments affected H19 and Igf2 imprinted gene expression in day 20 placenta. Our findings demonstrate that one contributor to the alteration in postnatal growth induced by periconceptional maternal LPD may derive from a gender-specific programming of imprinted gene expression originating within the preimplantation embryo itself.

Early Fetal Liver Readily Repopulates B Lymphopoiesis in Adult Bone Marrow

Fetal liver (FL) becomes a major organ of hematopoiesis at mouse embryonic day (E) 11 and E12, when definitive hematopoietic stem cells, originating from the aorta-gonads-mesonephros region, colonize the hepatic tissue. Unipotent B-cell progenitors are very rare in FL by day 12, whereas erythropoiesis prevails. We have studied hematopoiesis in FL from different gestational ages, with special emphasis on B lymphopoiesis. The mRNA levels of selected liver-specific genes, hematopoietic lineage-specific genes, and genes for selected cytokines/hormones as well as for their receptors were evaluated by real-time polymerase chain reaction in FL from E12.5, E14.5, and E17.5, adult liver and adult bone marrow (BM). The level of B lineage-related gene expression in FL was very low at E12.5. There was also a significantly lower fraction of B220+ and CD19+ B cells in E12.5 FL compared with E17.5 FL. To analyze whether these differences reflect different stem cell potentials occurring during FL development, 10(6) or 5 x 10(6) of FL cells collected from embryos at E12.5 or E17.5 and those from adult BM were transplanted into sublethally irradiated (3- or 6-Gy) congenic mice. Short-term and long-term repopulation of B and T cells and granulocyte/macrophage lineages from donor FL or adult BM cells were evaluated in competition to adult hematopoiesis of sublethally irradiated recipients. In short-term repopulation, the transplantation of E12.5 FL cells resulted in a lower blood chimerism compared with that of E17.5 FL cells. However, the proportion of B lymphopoiesis exerted by E12.5 FL cells was not different from that of E17.5 FL or adult BM. This study demonstrates that E12.5 FL contains hematopoietic stem cells with fully developed B-cell repopulating capacity and that the developmental period of fetal hematopoiesis between E12.5 and E17.5 is not an obligatory phase for the adult B lymphopoiesis.

Inflammation of the dam has different effects on the binding of maternal and fetal rat liver nucleoproteins to the rat haptoglobin gene promoter.

Transcriptional regulation of binding interactions between nucleoproteins and the hormone response element (RE) of the rat haptoglobin (Hp) gene was investigated in adult and fetal livers of rats exposed to inflammation on day 19 of pregnancy. Nuclear extracts from the embryonal liver displayed a barely detectable binding-affinity for hormone RE, but in extracts from the adult liver it was noticeable. The acute phase reaction of the mother promoted an increase of Hp gene expression in both adult and fetal livers, relying on stage-specific changes in hormone RE binding activities of nucleoplasmic proteins. The results indicated that the elevation of Hp gene expression in fetal liver to the steady basal level found in adults required the induction of new trans-acting proteins, whereas an overexpression of this gene in adult acute phase liver relied essentially on an increase in the binding-affinity of the preexisting hormone RE binding proteins.

The Early Expression of Some Human Autoantibody‐Associated Heavy Chain Variable Region Genes is Controlled by Specific Regulatory Elements

Recent molecular cloning studies have revealed that some autoantibodies may be encoded directly by germline Ig variable (V) genes without any somatic mutation, suggesting strongly that such autoantibodies are physiologically important. Independent analyses of Ig gene expression in a human fetal liver showed that only nine heavy chain V (Vh) genes were used, out of a potential germline Vh gene repertoire of 100-200. We have observed that four of these nine Vh genes encode sequences identical or almost identical to human autoantibody heavy chains. This unexpected overlap implies that some autoantibodies are expressed preferentially during early development. Recent structural analyses of two Vh3 genes expressed in fetal liver revealed many more enhancer-like sequences in the flanking regions than expected for a typical Vh gene. It is hypothesized that these autoantibody-related Vh genes may contain various combinations of cis regulatory elements which influence their specific expression during early ontogenic development. Furthermore, these observations are consistent with network hypotheses, which suggest that early B-cell development is driven by reactivity with self. The cis regulatory elements in the autoantibody genes may act in concert with the positional effects that have been shown to facilitate Vh gene engagement.