Prenatal stress is associated with an increased vulnerability to neurodevelopmental disorders, including autism and schizophrenia. To determine the critical time window when fetal antecedents may induce a disease predisposition, we examined behavioral responses in offspring exposed to stress during early, mid, and late gestation. We found that male offspring exposed to stress early in gestation displayed maladaptive behavioral stress responsivity, anhedonia, and an increased sensitivity to selective serotonin reuptake inhibitor treatment. Long-term alterations in central corticotropin-releasing factor (CRF) and glucocorticoid receptor (GR) expression, as well as increased hypothalamic–pituitary–adrenal (HPA) axis responsivity, were present in these mice and likely contributed to an elevated stress sensitivity. Changes in CRF and GR gene methylation correlated with altered gene expression, providing important evidence of epigenetic programming during early prenatal stress. In addition, we found the core mechanism underlying male vulnerability may involve sex-specific placenta responsivity, where stress early in pregnancy significantly increased expression of PPARα (peroxisome proliferator-activated receptor α), IGFBP-1 (insulin-like growth factor binding protein 1), HIF3α (hypoxia-inducible factor 3a), and GLUT4 (glucose transporter 4) in male placentas but not females. Examination of placental epigenetic machinery revealed basal sex differences, providing further evidence that sex-specific programming begins very early in pregnancy, and may contribute to the timing and vulnerability of the developing fetus to maternal perturbations. Overall, these results indicate that stress experience early in pregnancy may contribute to male neurodevelopmental disorders through impacts on placental function and fetal development.

https://www.jneurosci.org/content/jneuro/28/36/9055.full.pdf

Sex-specific programming of offspring emotionality after stress early in pregnancy.

https://www.gastrojournal.org/article/S0016-5085(09)01378-X/pdf

Gastroesophageal Reflux Might Cause Esophagitis Through a Cytokine-Mediated Mechanism Rather Than Caustic Acid Injury

Maternal obesity and diet consumption during pregnancy have been linked to offspring adiposity, cardiovascular disease, and impaired glucose metabolism. Furthermore, nutrition during development is clearly linked to somatic growth. However, few studies have examined whether phenotypes derived from maternal high-fat diet exposure can be passed to subsequent generations and by what mechanisms this may occur. Here we report the novel finding of a significant body length increase that persisted across at least two generations of offspring in response to maternal high-fat diet exposure. This phenotype is not attributable to altered intrauterine conditions or maternal feeding behavior because maternal and paternal lineages were able to transmit the effect, supporting a true epigenetic manner of inheritance. We also detected a heritable feature of reduced insulin sensitivity across two generations. Alterations in the GH secretagogue receptor (GHSR), the GHSR transcriptional repressor AF5q31, plasma IGF-I concentrations, and IGF-binding protein-3 (IGFBP3) suggest a contribution of the GH axis. These studies provide evidence that the heritability of body length and glucose homeostasis are modulated by maternal diet across multiple generations, providing a mechanism where length can increase rapidly in concert with caloric availability.

/pdf/maternal-high-fat-diet-promotes-body-length-increases-and-2d17ie3dip.pdf

Maternal High-Fat Diet Promotes Body Length Increases and Insulin Insensitivity in Second-Generation Mice

Differentiation-Specific Histone Modifications Reveal Dynamic Chromatin Interactions and Partners for the Intestinal Transcription Factor CDX2

History, Molecular Mechanisms, and Endoscopic Treatment of Barrett's Esophagus

Caudal-related homeobox 2 (Cdx2) has been suggested as an early marker of Barrett's esophagus (BE), which is the premalignant lesion of esophageal adenocarcinoma (EAC). However, the mechanism of ectopic Cdx2 expression in the esophageal epithelial cells and its role in the development of BE remained unclear. RT-PCR, pyrosequencing and methylation-specific PCR were used to determine expression and promoter methylation of Cdx2 in human esophageal epithelial cells (HET1A and SEG1) after treatment with 5-aza-2'-deoxycytidine (DAC), acid, bile acids and their combination. HET1A cells with stable transfection of Cdx2 were characterized for morphology and gene expression profiles with Affymetrix array. We found Cdx2 was expressed in most human EAC cell lines, but not in squamous epithelial cell lines. DAC-induced demethylation and expression of Cdx2 in HET1A and SEG1 cells, and treatment with a DNA methylating agent counteracted the effect of DAC. Treatment of HET1A and SEG1 cells with acid, bile acids or both also resulted in promoter demethylation and expression of Cdx2. HET1A cells with stable transfection of human Cdx2 formed crypt-like structures in vitro. Microarray analysis and quantitative real-time PCR showed that stable transfection of Cdx2 up-regulated differentiation markers of intestinal columnar epithelial cells and goblet cells in HET1A cells. This may be partially due to modulation of Notch signaling pathway, as western blotting confirmed down-regulation of Hes1 and up-regulation of Atoh1 and Muc2. Our data suggest that exposure to acid and/or bile acids may activate Cdx2 expression in human esophageal epithelial cells through promoter demethylation, and ectopic Cdx2 expression in esophageal squamous epithelial cells may contribute to intestinal metaplasia of the esophagus.

Regulation of Cdx2 expression by promoter methylation, and effects of Cdx2 transfection on morphology and gene expression of human esophageal epithelial cells

Pyrosequencing™ of a recA gene variable region for Burkholderia cepacia complex genomovar identification

Pyrosequencing is a non-gel-based, real-time approach to sequence DNA by monitoring DNA polymerase activity using an enzymatic luminometric inorganic pyrophosphate detection assay. Using pyrosequencing for microbiology identification or drug resistance screening involves three main steps: assay design, PCR, and the actual pyrosequencing. To make pathogen identifications, pyrosequencing assays have frequently used the highly conserved targets that are also used in Sanger sequencing, specifically 16S rRNA in bacteria and mycobacteria and the 18S/internal transcribed spacer (ITS) region in fungi, although other targets are used when the conserved regions are inadequate for species identification. 16S rRNA is a bacterial identification target commonly used by many different technologies, including Sanger sequencing. Pyrosequencing is a real-time sequencing technology alternative to Sanger sequencing. The versatility of pyrosequencing allows bacteria to be identified via 16S single-nucleotide polymorphism (SNP) analysis or de novo sequencing of the variable regions. Pyrosequencing enabled the differentiation of Hantaan virus from Seoul virus, the most common hemorrhagic fever with renal syndrome pathogens in Asia, and of Andes virus from Sin Nombre virus, the two viruses that cause hantavirus cardiopulmonary syndrome in the Americas. Pyrosequencing has been compared prospectively to conventional sequencing for the diagnosis and genotyping of the parasite Toxoplasma gondii. Microbial drug resistance is usually developed over time by the introduction of a point mutation or sometimes multiple mutations. The ability to fuse real-time PCR with real-time pyrosequencing may be the catalyst that leads to widespread adoption of pyrosequencing in clinical laboratories.

Liying Yan

Papers

Regulation of Cdx2 expression by promoter methylation, and effects of Cdx2 transfection on morphology and gene expression of human esophageal epithelial cells

Pyrosequencing™ of a recA gene variable region for Burkholderia cepacia complex genomovar identification

Detection Methodology: Pyrosequencing