The effect of Vdr gene ablation on global gene expression in the mouse placenta.

The effects of vitamin D are mediated through the vitamin D receptor (VDR), a predominantly nuclear receptor, expressed in numerous tissues including the placenta. VDR and the retinoid X receptor (RXR) form a dimer complex which binds to genomic vitamin D responsive elements located primarily in promoter regions and recruit cell-specific transcription factor complexes which regulate the expression of numerous genes. To investigate the role of VDR on regulating placental gene expression, mice heterozygous (+/-) for an ablated Vdr allele (C57Bl6 strain B6.129S4-VDRtm1Mbd/J, Jackson Laboratory) were mated to generate Vdr(+/+), Vdr(+/-) and Vdr (-/-) fetuses and placental samples were collected at day 18.5 of pregnancy. RNA was isolated from placental tissue with global gene expression measured using Affymetrix Mouse Gene 2.1 ST Arrays to assess the effects of VDR on global gene expression in the placenta. All raw array data are deposited in Gene Expression Omnibus (GEO) under accession GSE61583.

Vitamin D Receptor Gene Ablation in the Conceptus Has Limited Effects on Placental Morphology, Function and Pregnancy Outcome.

Vitamin D deficiency has been implicated in the pathogenesis of several pregnancy complications attributed to impaired or abnormal placental function, but there are few clues indicating the mechanistic role of vitamin D in their pathogenesis. To further understand the role of vitamin D receptor (VDR)-mediated activity in placental function, we used heterozygous Vdr ablated C57Bl6 mice to assess fetal growth, morphological parameters and global gene expression in Vdr null placentae. Twelve Vdr+/- dams were mated at 10-12 weeks of age with Vdr+/- males. At day 18.5 of the 19.5 day gestation in our colony, females were euthanised and placental and fetal samples were collected, weighed and subsequently genotyped as either Vdr+/+, Vdr+/- or Vdr-/-. Morphological assessment of placentae using immunohistochemistry was performed and RNA was extracted and subject to microarray analysis. This revealed 25 genes that were significantly differentially expressed between Vdr+/+ and Vdr-/- placentae. The greatest difference was a 6.47-fold change in expression of Cyp24a1 which was significantly lower in the Vdr-/- placentae (P<0.01). Other differentially expressed genes in Vdr-/- placentae included those involved in RNA modification (Snord123), autophagy (Atg4b), cytoskeletal modification (Shroom4), cell signalling (Plscr1, Pex5) and mammalian target of rapamycin (mTOR) signalling (Deptor and Prr5). Interrogation of the upstream sequence of differentially expressed genes identified that many contain putative vitamin D receptor elements (VDREs). Despite the gene expression differences, this did not contribute to any differences in overall placental morphology, nor was function affected as there was no difference in fetal growth as determined by fetal weight near term. Given our dams still expressed a functional VDR gene, our results suggest that cross-talk between the maternal decidua and the placenta, as well as maternal vitamin D status, may be more important in determining pregnancy outcome than conceptus expression of VDR.

Irinotecan-induced mucositis is associated with changes in intestinal mucins.

PURPOSE: Mucositis is a major oncological problem, caused by the cytotoxic effects of cancer chemotherapy and radiotherapy. Irinotecan is used to treat a variety of solid tumours, through the inhibition of DNA topoisomerase I and is linked with severe mucositis and diarrhoea. Mucus production appears to be increased, which may contribute to the development of diarrhoea. METHODS: Dark agouti rats were treated with irinotecan, and tissues collected at several time points up to 72 h. Goblet cells and mucin secretion were investigated, as well as mucin expression (Muc2 and Muc4) and kruppel-like factor (Klf) 4 using immunohistochemistry in the gastrointestinal tract. Both goblet cells and cells positive for Muc expression were counted, and analysed statistically using the Mann-Whitney U test with Bonferroni correction. RESULTS: Goblet cells decreased significantly after irinotecan treatment. However, mucin secretion increased. Mucin expression changed significantly after treatment. Muc2 and Muc4 decreased significantly in the villi of the jejunum after treatment, Muc2 and Muc4 decreased significantly in the crypts. Muc2 decreased significantly in the colon. CONCLUSIONS: Irinotecan causes an increase in mucin secretion and a net decrease in mucin-producing goblet cells, and the expression of Muc2 and Muc4 in the gastrointestinal tract is altered following treatment. Increased mucin secretion is likely to be related to altered mucin expression, and may contribute to chemotherapy-induced diarrhoea.

PDE4B polymorphisms and decreased PDE4B expression are associated with schizophrenia.

Schizophrenia has a complex genetic underpinning and variations in a number of candidate genes have been identified that confer risk of developing the disorder. We report in the present studies that several single nucleotide polymorphisms (SNPs) and a two-SNP haplotype in PDE4B are associated with an increased incidence of schizophrenia in two large populations of Caucasian and African American patients. The SNPs in PDE4B associated with schizophrenia occur in intronic sequences in the vicinity of a critical splice junction that gives rise to the expression of PDE4B isoforms with distinct regulation and function. We also observed specific decreases in phosphodiesterase 4B (PDE4B) isoforms in brain tissue obtained postmortem from patients diagnosed with schizophrenia and bipolar disorder. PDE4B metabolically inactivates the second messenger cAMP to regulate intracellular signaling in neurons throughout the brain. Thus, the present observations suggest that dysregulation of intracellular signaling mediated by PDE4B is a significant factor in the cause and expression, respectively, of schizophrenia and bipolar disorder and that targeting PDE4B-regulated signaling pathways may yield new therapies to treat the totality of these disorders.

Qualind: A method for assessing the accuracy of automated tests.

As audiology strives for cost containment, standardization, accuracy of tests, and accountability, greater use of automated tests is likely. Highly skilled audiologists employ quality control factors that contribute to test accuracy, but they are not formally included in test protocols, resulting in a wide range of accuracy, owing to the various skill and experience levels of clinicians. A method that incorporates validated quality indicators may increase accuracy and enhance access to accurate hearing tests. This report describes a quality assessment method that can be applied to any test that (1) requires behavioral or physiologic responses, (2) is associated with factors that correlate with accuracy, and (3) has an available independent measure of the dimension being assessed, including tests of sensory sensitivity, cognitive function, aptitude, academic achievement, and personality. In this report the method is applied to AMTAS, an automated method for diagnostic pure-tone audiometry.

Glial fibrillary acidic protein is reduced in cerebellum of subjects with major depression, but not schizophrenia.

Glial fibrillary acidic protein (GFAP) is a major protein of astrocyte intermediate filaments and a specific marker for astrocytes. Alterations in levels of GFAP may reflect pathological regulation of neuronal function and survival as well as abnormal synaptogenesis and neurotransmission. We employed quantitative gel electrophoresis and Western blotting to measure levels of GFAP in cerebella of 60 subjects divided equally among schizophrenia, bipolar disorder, major depression, and normal controls. GFAP levels were reduced by 32%, 17% and 14.5% in depressed, bipolar, and schizophrenic cerebella, respectively, versus controls. Only the depressed value was significantly different (p=0.015 Post-hoc Bonferroni test). Measurement of beta-actin levels showed no differences between the various groups. No significant effects of confounding variables were found. This is the first demonstration of GFAP reductions in cerebellum of subjects with mood disorders and schizophrenia, thereby adding to the reports of reductions in GFAP/glial cell counts in other brain regions of subjects with major depression, thus suggesting a downregulation of glial function in this disorder.