The role of BDNF methylation and Val66Met in amygdala reactivity during emotion processing

Epigenetic alterations of the brain‐derived neurotrophic factor (BDNF) gene have been associated with psychiatric disorders in humans and with differences in amygdala BDNF mRNA levels in rodents. This human study aimed to investigate the relationship between the functional BDNF‐Val⁶⁶Met polymorphism, its surrounding DNA methylation in BDNF exon IX, amygdala reactivity to emotional faces, and personality traits. Healthy controls (HC, n = 189) underwent functional MRI during an emotional face‐matching task. Harm avoidance, novelty seeking and reward dependence were measured using the Tridimensional Personality Questionnaire (TPQ). Individual BDNF methylation profiles were ascertained and associated with several BDNF single nucleotide polymorphisms surrounding the BDNF‐Val⁶⁶Met, amygdala reactivity, novelty seeking and harm avoidance. Higher BDNF methylation was associated with higher amygdala reactivity (x = 34, y = 0, z = ?26, t₍₁₆₆₎ = 3.00, TFCE = 42.39, p_(FWE) = .045), whereby the BDNF‐Val⁶⁶Met genotype per se did not show any significant association with brain function. Furthermore, novelty seeking was negatively associated with BDNF methylation (r = ?.19, p = .015) and amygdala reactivity (r = ?.17, p = .028), while harm avoidance showed a trend for a positive association with BDNF methylation (r = .14, p = .066). The study provides first insights into the relationship among BDNF methylation, BDNF genotype, amygdala reactivity and personality traits in humans, highlighting the multidimensional relations among genetics, epigenetics, and neuronal functions. The present study suggests a possible involvement of epigenetic BDNF modifications in psychiatric disorders and related brain functions, whereby high BDNF methylation might reduce BDNF mRNA expression and upregulate amygdala reactivity.     

Sequence Conservation of Glycerophosphodiester Phosphodiesterase among Treponema pallidum Strains

Previous investigations have demonstrated that immunization with Treponema pallidum subsp. pallidum glycerophosphodiester phosphodiesterase significantly protects rabbits from subsequent treponeme challenge. In this report, we show that the glycerophosphodiester phosphodiesterase amino acid sequence is conserved among 12 strains from a total of five pathogenic treponemes. The invariant nature of this immunoprotective antigen makes it an attractive candidate for inclusion in a universal subunit vaccine against T. pallidum infection. In addition, these studies show a silent nucleotide substitution at position 579 of the gpd open reading frame which is consistently observed in the non-T. pallidum subsp. pallidum strains. This sequence alteration introduces a PleI restriction site in the nonsyphilis strains and thus allows genetic differentiation from T. pallidum subsp. pallidum strains.     

Type I interferons have opposing effects during the emergence and recovery phases of colitis

The contribution of the innate immune system to inflammatory bowel disease (IBD) is under intensive investigation. Research in animal models has demonstrated that type I interferons (IFN‐Is) protect from IBD. In contrast, studies of patients with IBD have produced conflicting results concerning the therapeutic potential of IFN‐Is. Here, we present data suggesting that IFN‐Is play dual roles as regulators of intestinal inflammation in dextran sodium sulfate (DSS)‐treated C57BL/6 mice. Though IFN‐Is reduced acute intestinal damage and the abundance of colitis‐associated intestinal bacteria caused by treatment with a high dose of DSS, they also inhibited the resolution of inflammation after DSS treatment. IFN‐Is played an anti‐inflammatory role by suppressing the release of IL‐1β from the colon MHC class II⁺ cells. Consistently, IL‐1 receptor blockade reduced the severity of inflammation in IFN‐I receptor‐deficient mice and myeloid cell‐restricted ablation of the IFN‐I receptor was detrimental. The proinflammatory role of IFN‐Is during recovery from DSS treatment was caused by IFN‐I‐dependent cell apoptosis as well as an increase in chemokine production and infiltrating inflammatory monocytes and neutrophils. Thus, IFN‐Is play opposing roles in specific phases of intestinal injury and inflammation, which may be important for guiding treatment strategies in patients.     

The internalization of the IgG2a antigen receptor does not require the association with Ig-α and Ig-β but the activation of protein tyrosine kinases does

The B cell antigen receptor of class IgM is a multimeric protein complex containing the membrane-bound immunoglobulin molecule and a heterodimer of the two B cell-specific transmembrane proteins Ig-α and Ig-β. The B cell antigen receptor fulfills a dual role on the surface of B cells. First, it is a signal transduction complex which can activate protein tyrosine kinases and induce the release of Ca²⁺ ions from intracellular stores. Second, its internalization mediates the specific uptake of bound antigens, which are processed intracellularly and presented as major histocompatibility complex-bound peptides on the cell surface. In case of the IgM antigen receptor, the association with the heterodimer is necessary for expression of large amounts of IgM on the surface. We show here that the IgG2a antigen receptor can be expressed on the surface of myeloma cells in two structurally different forms: either with or without the Ig-α/Ig-β heterodimer. A functional comparison of the two forms of antigen receptors demonstrates that the Ig-α and Ig-β molecules are required for the activation of protein tyrosine kinases after cross-linking of the B cell antigen receptor. In contrast, both forms of IgG2a are equally well internalized. This suggests that Ig-α and Ig-β are essential for signal transduction through the IgG2a antigen receptor, whereas internalization can occur independently of the heterodimer.     

Vitrification preserves murine and human donor cells for generation of tissue-engineered intestine

Background

Short bowel syndrome causes significant morbidity and mortality. Tissue-engineered intestine may serve as a viable replacement. Tissue-engineered small intestine (TESI) has previously been generated in the mouse model from donor cells that were harvested and immediately reimplanted; however, this technique may prove impossible in children who are critically ill, hemodynamically unstable, or septic. We hypothesized that organoid units (OU), multicellular clusters containing epithelium and mesenchyme, could be cryopreserved for delayed production of TESI.

Methods

OU were isolated from <3 wk-old mouse or human ileum. OU were then cryopreserved by either standard snap freezing or vitrification. In the snap freezing protocol, OU were suspended in cryoprotectant and transferred directly to −80°C for storage. The vitrification protocol began with a stepwise increase in cryoprotectant concentration followed by liquid supercooling of the OU solution to −13°C and nucleation with a metal rod to induce vitrification. Samples were then cooled to −80°C at a controlled rate of −1°C/min and subsequently plunged into liquid nitrogen for long-term storage. OU from both groups were maintained in cryostorage for at least 72 h and thawed in a 37°C water bath. Cryoprotectant was removed with serial sucrose dilutions and OU were assessed by Trypan blue assay for post-cryopreservation viability. Via techniques previously described by our laboratory, the thawed murine or human OU were either cultured in vitro or implanted on a scaffold into the omentum of a syngeneic or irradiated Nonobese Diabetic/Severe Combined Immunodeficiency, gamma chain deficient adult mouse. The resultant TESI was analyzed by histology and immunofluorescence.

Results

After cryopreservation, the viability of murine OU was significantly higher in the vitrification group (93 ± 2%, mean ± standard error of the mean) compared with standard freezing (56 ± 6%) (P < 0.001, unpaired t-test, n = 25). Human OU demonstrated similar viability after vitrification (89 ± 2%). In vitro culture of thawed OU produced expanding epithelial spheres supported by a layer of mesenchyme. TESI was successfully generated from the preserved OU. Hematoxylin and eosin staining demonstrated a mucosa composed of a simple columnar epithelium whereas immunofluorescence staining confirmed the presence of both progenitor and differentiated epithelial cells. Furthermore, beta-2-microglobulin confirmed that the human TESI epithelium originated from human cells.

Conclusions

We demonstrated improved multicellular viability after vitrification over conventional cryopreservation techniques and the first successful vitrification of murine and human OU with subsequent TESI generation. Clinical application of this method may allow for delayed autologous implantation of TESI for children in extremis.     

Collaborative genetic mapping of 12 forensic short tandem repeat (STR) loci on the human X chromosome

A large number of short tandem repeat (STR) markers spanning the entire human X chromosome have been described and established for use in forensic genetic testing. Due to their particular mode of inheritance, X-STRs often allow easy and informative haplotyping in kinship analyses. Moreover, some X-STRs are known to be tightly linked so that, in combination, they constitute even more complex genetic markers than each STR taken individually. As a consequence, X-STRs have proven particularly powerful in solving complex cases of disputed blood relatedness. However, valid quantification of the evidence provided by X-STR genotypes in the form of likelihood ratios requires that the recombination rates between markers are exactly known. In a collaborative family study, we used X-STR genotype data from 401 two- and three-generation families to derive valid estimates of the recombination rates between 12 forensic markers widely used in forensic testing, namely DXS10148, DXS10135, DXS8378 (together constituting linkage group I), DXS7132, DXS10079, DXS10074 (linkage group II), DXS10103, HPRTB, DXS10101 (linkage group III), DXS10146, DXS10134 and DXS7423 (linkage group IV). Our study is the first to simultaneously allow for mutation and recombination in the underlying likelihood calculations, thereby obviating the bias-prone practice of excluding ambiguous transmission events from further consideration. The statistical analysis confirms that linkage groups I and II are transmitted independently from one another whereas linkage groups II, III and IV are characterised by inter-group recombination fractions that are notably smaller than 50%. Evidence was also found for recombination within all four linkage groups, with recombination fraction estimates ranging as high as 2% in the case of DXS10146 and DXS10134.     

Natural History of Mild and of Moderate Aortic Stenosis—New Insights From a Large Prospective European Study

Increased life expectancy has led to a higher prevalence of calcific aortic valve disease. Both ends of the disease spectrum—sclerosis of the aortic valve without hemodynamic obstruction and the late stage of aortic valve stenosis (AS)—have been associated with increased morbidity and mortality. This raises the question of the prognostic contribution of atherosclerotic diseases and other comorbidities as opposed to the hemodynamic effect of obstructive AS. Hence, the evaluation of asymptomatic patients with mild or moderate AS without comorbidities is of major interest. In the Simvastatin and Ezetimibe in Aortic Stenosis study, with the exception of hypertension, comorbidities were excluded, thus allowing an analysis of the effect of pure AS as well as the effect of hypertension on the progression and outcome of AS.