Tissue factor expression on monocyte subpopulations during normal pregnancy.

Pregnancy is often referred to as a hypercoaguable state due to changes in the haemostatic system. Tissue factor (TF) is the initiator of blood clotting in vivo. The effect of pregnancy on monocyte TF expression was determined in a longitudinal case control study, (89 pregnant, 39 non-pregnant). Using whole blood flow cytometry and CD14 as a monocyte marker, TF expression was measured on all CD14 positive, CD14Bright and CD14Dim cells. TF expression was significantly lower in pregnant women than in non-pregnant control subjects, on all CD14 positive cells at 20 and 35 weeks, on CD14Bright cells at 12 and 35 weeks and on CD14Dim cells at 20 weeks. Additionally, we report that a higher percentage of CD14Dim than CD14Bright cells express TF. These results suggest that, in order to maintain homeostasis in haemostasis in an otherwise hypercoaguable state, monocyte TF expression is reduced during normal pregnancy.

Differential expression of liver fluke β-tubulin isotypes at selected life cycle stages

We have shown that Fasciola hepatica expresses at least six ß-tubulins in the adult stage of its life cycle, designated F.hep-ß-tub1-6 (Ryan et al., 2008). Here we show that different complements of tubulin isotypes are expressed in different tissues and at different life cycle stages; this information may inform the search for novel anthelmintics. The predominant (as judged by quantitative PCR) isotype transcribed at the adult stage was F.hep-ß-tub1 and immunolocalisation studies revealed that this isotype occurred mainly in mature spermatozoa and vitelline follicles. Quantitative PCR indicated that changes occurred in the transcription levels of ß-tubulin isotypes at certain life cycle stages and may be of importance in the efficacy of benzimidazole-based anthelmintic drugs, but there were no significant differences between the triclabendazole (TCBZ)-susceptible Leon isolate and the TCBZ-resistant Oberon isolate in the transcription levels of each of the isotypes. When three well-characterised isolates with differing susceptibilities to TCBZ were compared, only one amino acid change resulting from a homozygous coding sequence difference (Gly269Ser) in isotype 4 was observed. However, this change was not predicted to alter the overall structure of the protein. In conclusion, these findings indicate that there is tissue-specific expression of tubulin isotypes in the liver fluke but the development of resistance to TCBZ is not associated with changes in its presumed target molecule.

The TGF-β-inducible miR-23a cluster attenuates IFN-γ levels and antigen-specific cytotoxicity in human CD8+ T cells

Cytokine secretion and degranulation represent key components of CD8(+) T-cell cytotoxicity. While transcriptional blockade of IFN-γ and inhibition of degranulation by TGF-β are well established, we wondered whether TGF-β could also induce immune-regulatory miRNAs in human CD8(+) T cells. We used miRNA microarrays and high-throughput sequencing in combination with qRT-PCR and found that TGF-β promotes expression of the miR-23a cluster in human CD8(+) T cells. Likewise, TGF-β up-regulated expression of the cluster in CD8(+) T cells from wild-type mice, but not in cells from mice with tissue-specific expression of a dominant-negative TGF-β type II receptor. Reporter gene assays including site mutations confirmed that miR-23a specifically targets the 3'UTR of CD107a/LAMP1 mRNA, whereas the further miRNAs expressed in this cluster-namely, miR-27a and -24-target the 3'UTR of IFN-γ mRNA. Upon modulation of the miR-23a cluster by the respective miRNA antagomirs and mimics, we observed significant changes in IFN-γ expression, but only slight effects on CD107a/LAMP1 expression. Still, overexpression of the cluster attenuated the cytotoxic activity of antigen-specific CD8(+) T cells. These functional data thus reveal that the miR-23a cluster not only is induced by TGF-β, but also exerts a suppressive effect on CD8(+) T-cell effector functions, even in the absence of TGF-β signaling.

Tissue- specific DNA methylation profiles in newborns

Experimental and epidemiological studies demonstrate that fetal growth restriction and low birth weight enhance the risk of chronic diseases in adulthood. Derangements in tissue-specific epigenetic programming of fetal and placental tissues are a suggested mechanism of which DNA methylation is best understood. DNA methylation profiles in human tissue are mostly performed in DNA from white blood cells. The objective of this study was to assess DNA methylation profiles of IGF2 DMR and H19 in DNA derived from four tissues of the newborn. We obtained from 6 newborns DNA from fetal placental tissue (n = 5), umbilical cord CD34+ hematopoietic stem cells (HSC) and CD34- mononuclear cells (MNC) (n = 6), and umbilical cord Wharton jelly (n = 5). HCS were isolated using magnetic-activated cell separation. DNA methylation of the imprinted fetal growth genes IGF2 DMR and H19 was measured in all tissues using quantitative mass spectrometry. ANOVA testing showed tissue-specific differences in DNA methylation of IGF2 DMR (p value 0.002) and H19 (p value 0.001) mainly due to a higher methylation of IGF2 DMR in Wharton jelly (mean 0.65, sd 0.14) and a lower methylation of H19 in placental tissue (mean 0.25, sd 0.02) compared to other tissues. This study demonstrates the feasibility of the assessment of differential tissue specific DNA methylation. Although the results have to be confirmed in larger sample sizes, our approach gives opportunities to investigate epigenetic profiles as underlying mechanism of associations between pregnancy exposures and outcome, and disease risks in later life.

The tissue-specific processing of pro-opiomelanocortin

It is just over 30 years since the definitive identification of the adrenocorticotrophin (ACTH) precursor, pro-opiomelanocotin (POMC). Although first characterised in the anterior and intermediate lobes of the pituitary, POMC is also expressed in a number of both central and peripheral tissues including the skin, central nervous tissue and placenta. Following synthesis, POMC undergoes extensive post-translational processing producing not only ACTH, but also a number of other biologically active peptides. The extent and pattern of this processing is tissue-specific, the end result being the tissue dependent production of different combinations of peptides from the same precursor. These peptides have a diverse range of biological roles ranging from pigmentation to adrenal function to the regulation of feeding. This level of complexity has resulted in POMC becoming the archetypal model for prohormone processing, illustrating how a single protein combined with post-translational modification can have a diverse number of roles.

The promoter of a gene encoding an isoflavone reductase-like protein in coffee (Coffea arabica) drives a stress-responsive expression in leaves

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Physical training prevents body weight gain but does not modify adipose tissue gene expression

The relationship of body weight (BW) with white adipose tissue (WAT) mass and WAT gene expression pattern was investigated in mice submitted to physical training (PT). Adult male C57BL/6 mice were submitted to two 1.5-h daily swimming sessions (T, N = 18), 5 days/week for 4 weeks or maintained sedentary (S, N = 15). Citrate synthase activity increased significantly in the T group (P < 0.05). S mice had a substantial weight gain compared to T mice (4.06 ± 0.43 vs 0.38 ± 0.28 g, P < 0.01). WAT mass, adipocyte size, and the weights of gastrocnemius and soleus muscles, lung, kidney, and adrenal gland were not different. Liver and heart were larger and the spleen was smaller in T compared to S mice (P < 0.05). Food intake was higher in T than S mice (4.7 ± 0.2 vs 4.0 ± 0.3 g/animal, P < 0.05) but oxygen consumption at rest did not differ between groups. T animals showed higher serum leptin concentration compared to S animals (6.37 ± 0.5 vs 3.11 ± 0.12 ng/mL). WAT gene expression pattern obtained by transcription factor adipocyte determination and differentiation-dependent factor 1, fatty acid synthase, malic enzyme, hormone-sensitive lipase, adipocyte lipid binding protein, leptin, and adiponectin did not differ significantly between groups. Collectively, our results showed that PT prevents BW gain and maintains WAT mass due to an increase in food intake and unchanged resting metabolic rate. These responses are closely related to unchanged WAT gene expression patterns.