Super‐resolution structure of DNA significantly differs in buccal cells of controls and Alzheimer's patients

The advent of super‐resolution microscopy allowed for new insights into cellular and physiological processes of normal and diseased cells. In this study, we report for the first time on the super‐resolved DNA structure of buccal cells from patients with Alzheimer's disease (AD) versus age‐ and gender‐matched healthy, non‐caregiver controls. In this super‐resolution study cohort of 74 participants, buccal cells were collected and their spatial DNA organization in the nucleus examined by 3D Structured Illumination Microscopy (3D‐SIM). Quantitation of the super‐resolution DNA structure revealed that the nuclear super‐resolution DNA structure of individuals with AD significantly differs from that of their controls (p < 0.05) with an overall increase in the measured DNA‐free/poor spaces. This represents a significant increase in the interchromatin compartment. We also find that the DNA structure of AD significantly differs in mild, moderate, and severe disease with respect to the DNA‐containing and DNA‐free/poor spaces. We conclude that whole genome remodeling is a feature of buccal cells in AD.     

A decade of colonization: the spread of the Asian tiger mosquito in Pennsylvania and implications for disease risk

In recent decades, the Asian tiger mosquito expanded its geographic range throughout the northeastern United States, including Pennsylvania. The establishment of Aedes albopictus in novel areas raises significant public health concerns, since this species is a highly competent vector of several arboviruses, including chikungunya, West Nile, and dengue. In this study, we used geographic information systems (GIS) to examine a decade of colonization by Ae. albopictus throughout Pennsylvania between 2001 and 2010. We examined the spatial and temporal distribution of Ae. albopictus using spatial statistical analysis and examined the risk of dengue virus transmission using a model that captures the probability of transmission. Our findings show that since 2001, the Ae. albopictus population in Pennsylvania has increased, becoming established and expanding in range throughout much of the state. Since 2010, imported cases of dengue fever have been recorded in Pennsylvania. Imported cases of dengue, in combination with summer temperatures conducive for virus transmission, raise the risk of local disease transmission.     

Sex hormone-binding globulin and thrombin generation in women using hormonal contraception

Objectives: We investigated the impact of serum sex hormone-binding globulin (SHBG) on thrombin generation (TG) in women according to hormonal contraception.

Patients and methods: A cross-sectional study of SHBG and TG measured via calibrated automated thrombography was conducted in 150 healthy women, including 75 users of combined oral contraceptives (COC), 22 users of progestin-only contraceptives (POC) and 53 nonusers.

Results: COC but not POC-users had significantly higher SHBG levels compared with nonusers. In hormonal contraceptive users, SHBG was positively associated with both activated protein C (APC) resistance and baseline TG, and protein S and prothrombin were important mediators.

Conclusion: These data provide further evidence that SHBG may be used as a biomarker in assessing prothrombotic profile of hormonal contraception.     

Nuclear magnetic resonance-based metabolomics of OCT-embedded frozen kidney samples in mouse and man following standardized pre-analytics

Introduction

Pre-analytical processing significantly affects tissue metabolomes. Since most frozen kidney samples are stored after embedding, standardization of cryoprotective medium removal before metabolomics is essential.

Objectives

We used rodent and human kidney samples to develop an easy and robust pre-analytical procedure compatible with ¹H-nuclear magnetic resonance (NMR)-based metabolomics.

Methods

In mice, renal ischemia was induced for 30 min, followed by 48-h reperfusion (I/R, n?=?6). Right kidneys were transversally cut in two fragments, and snap-frozen in liquid nitrogen (LN2) or in Optimal Cutting Temperature ^® (OCT) fixative. In man, double kidney biopsies were simultaneously obtained before transplantation (n?=?15), and snap-frozen in LN2 or OCT.

Results

¹H-NMR spectrum of pure OCT highlighted two major peaks, i.e. from 3.4 to 4.2 ppm (47.2%) and from 1.2 to 2.2 ppm (42.5%). ¹H-NMR spectra of mouse OCT kidneys were biased at 3.7. By contrast, ¹H-NMR analyses of mouse OCT kidneys iteratively rinsed in saline significantly discriminated sham versus I/R groups, with Q² at 0.695 (to be compared with Q² at 0.866 for LN2 sham vs. I/R kidneys). Discriminant metabolites were analogous in both OCT and LN2 kidneys, with a correlation coefficient of 0.83. In man, iteratively rinsing OCT kidneys in saline eliminated the spectral 3.7-peak, thereby making metabolomes of OCT kidneys interpretable and similar to LN2 samples, with a correlation coefficient of 0.73.

Conclusion

NMR metabolomics using OCT-frozen kidney samples is valuable in mouse and man, following standardized OCT removal. This may help use residual biobanked human tissues to better understand renal pathophysiology.

     

Novel 7-methoxy-6-oxazol-5-yl-2,3-dihydro-1H-quinazolin-4-ones as IMPDH inhibitors

The synthesis and biological activity of a novel series of 7-methoxy-6-oxazol-5-yl-2,3-dihydro-1H-quinazolin-4-ones are described. Some of these compounds were found to be potent inhibitors of inosine 5'-monophosphate dehydrogenase type II (IMPDH II).     

Recognition of ERK MAP kinase by PEA-15 reveals a common docking site within the death domain and death effector domain

PEA-15 is a multifunctional protein that modulates signaling pathways which control cell proliferation and cell death. In particular, PEA-15 regulates the actions of the ERK MAP kinase cascade by binding to ERK and altering its subcellular localization. The three-dimensional structure of PEA-15 has been determined using NMR spectroscopy and its interaction with ERK defined by characterization of mutants that modulate ERK function. PEA-15 is composed of an N-terminal death effector domain (DED) and a C-terminal tail of irregular structure. NMR 'footprinting' and mutagenesis identified elements of both the DED and tail that are required for ERK binding. Comparison of the DED-binding surface for ERK2 with the death domain (DD)-binding surface of Drosophila Tube revealed an unexpected similarity between the interaction modes of the DD and DED motifs in these proteins. Despite a lack of functional or sequence similarity between PEA-15 and Tube, these proteins utilize a common surface of the structurally similar DD and DED to recognize functionally diverse targets.     

The cross-priming APC requires a Rel-dependent signal to induce CTL

Induction of OVA-specific CTL by cross-priming requires help from CD4 T cells, which use CD154 to signal CD40 on the APC. To further dissect the molecular pathways involved in cross-priming, we examined the role of Rel, an NF-kappaB family member. c-rel(-/-) mice failed to generate OVA-specific CTL by cross-priming, but could induce CTL to HSV-1. Using chimeric mice, Rel expression was shown to be required by the APC, but not by the T cells. Notably, the deficiency in Rel could be overcome by triggering CD40, implying that the APC required Rel before receipt of the CD40 signal. These data suggest that the cross-priming APC must receive two signals before it can stimulate CTL. The first signal is Rel dependent and is required before activation of CD4 helper T cells, which then deliver the second signal using CD154 to trigger CD40.     

DEDD regulates degradation of intermediate filaments during apoptosis

Apoptosis depends critically on regulated cytoskeletal reorganization events in a cell. We demonstrate that death effector domain containing DNA binding protein (DEDD), a highly conserved and ubiquitous death effector domain containing protein, exists predominantly as mono- or diubiquitinated, and that diubiquitinated DEDD interacts with both the K8/18 intermediate filament network and pro-caspase-3. Early in apoptosis, both cytosolic DEDD and its close homologue DEDD2 formed filaments that colocalized with and depended on K8/18 and active caspase-3. Subsequently, these filamentous structures collapsed into intracellular inclusions that migrated into cytoplasmic blebs and contained DEDD, DEDD2, active caspase-3, and caspase-3-cleaved K18 late in apoptosis. Biochemical studies further confirmed that DEDD coimmunoprecipitated with both K18 and pro-caspase-3, and kinetic analyses placed apoptotic DEDD staining prior to caspase-3 activation and K18 cleavage. In addition, both caspase-3 activation and K18 cleavage was inhibited by expression of DEDDDeltaNLS1-3, a cytosolic form of DEDD that cannot be ubiquitinated. Finally, siRNA mediated DEDD knockdown cells exhibited inhibition of staurosporine-induced DNA degradation. Our data suggest that DEDD represents a novel scaffold protein that directs the effector caspase-3 to certain substrates facilitating their ordered degradation during apoptosis.     

Cholesterol distribution in the Golgi complex of DITNC1 astrocytes is differentially altered by fresh and aged amyloid beta-peptide-(1-42)

The Golgi complex plays an important role in cholesterol trafficking in cells, and amyloid beta-peptides (Abetas) alter cholesterol trafficking. The hypothesis was tested that fresh and aged Abeta-(1-42) would differentially modify Golgi cholesterol content in DINTC1 astrocytes and that the effects of Abeta-(1-42) would be associated with the region of the Golgi complex. Two different methods were used to determine the effects of Abeta-(1-42) on Golgi complex cholesterol. Confocal microscopy showed that fresh Abeta-(1-42) significantly increased cholesterol and that aged Abeta-(1-42) significantly reduced cholesterol content in the Golgi complex. Isolation of the Golgi complex into two fractions using density gradient centrifugation showed effects of aged Abeta-(1-42) similar to those observed with confocal microscopy but revealed the novel finding that fresh Abeta-(1-42) had opposite effects on the two Golgi fractions suggesting a specificity of Abeta-(1-42) perturbation of the Golgi complex. Phosphatidylcholine-phospholipase D activity, cell membrane cholesterol, and apolipoprotein E levels were associated with effects of fresh Abeta-(1-42) on cholesterol distribution but not with effects of aged Abeta-(1-42), arguing against a common mechanism. Extracellular Abeta-(1-42) targets the Golgi complex and disrupts cell cholesterol homeostasis, and this action of Abeta-(1-42) could alter cell functions requiring optimal levels of cholesterol.