Toll-like Receptor Agonists Promote Prolonged Triglyceride Storage in Macrophages

Macrophages in infected tissues may sense microbial molecules that significantly alter their metabolism. In a seeming paradox, these critical host defense cells often respond by increasing glucose catabolism while simultaneously storing fatty acids (FA) as triglycerides (TAG) in lipid droplets. We used a load-chase strategy to study the mechanisms that promote long term retention of TAG in murine and human macrophages. Toll-like receptor (TLR)1/2, TLR3, and TLR4 agonists all induced the cells to retain TAG for ≥3 days. Prolonged TAG retention was accompanied by the following: (a) enhanced FA uptake and FA incorporation into TAG, with long lasting increases in acyl-CoA synthetase long 1 (ACSL1) and diacylglycerol acyltransferase-2 (DGAT2), and (b) decreases in lipolysis and FA β-oxidation that paralleled a prolonged drop in adipose triglyceride lipase (ATGL). TLR agonist-induced TAG storage is a multifaceted process that persists long after most early pro-inflammatory responses have subsided and may contribute to the formation of “lipid-laden” macrophages in infected tissues.     

Fetal lung and placental methylation is associated with in utero nicotine exposure

In utero smoke exposure has been shown to have detrimental effects on lung function and to be associated with persistent wheezing and asthma in children. One potential mechanism of IUS effects could be alterations in DNA methylation, which may have life-long implications. The goal of this study was to examine the association between DNA methylation and nicotine exposure in fetal lung and placental tissue in early development; nicotine exposure in this analysis represents a likely surrogate for in-utero smoke. We performed an epigenome-wide analysis of DNA methylation in fetal lung tissue (n = 85, 41 smoke exposed (48%), 44 controls) and the corresponding placental tissue samples (n = 80, 39 smoke exposed (49%), 41 controls) using the Illumina HumanMethylation450 BeadChip array. Differential methylation analyses were conducted to evaluate the variation associated with nicotine exposure. The most significant CpG sites in the fetal lung analysis mapped to the PKP3 (P = 2.94 × 10⁻⁰³), ANKRD33B (P = 3.12 × 10⁻⁰³), CNTD2 (P = 4.9 × 10⁻⁰³) and DPP10 (P = 5.43 × 10⁻⁰³) genes. In the placental methylome, the most significant CpG sites mapped to the GTF2H2C and GTF2H2D genes (P = 2.87 × 10⁻⁰⁶ − 3.48 × 10⁻⁰⁵). One hundred and one unique CpG sites with P-values < 0.05 were concordant between lung and placental tissue analyses. Gene Set Enrichment Analysis demonstrated enrichment of specific disorders, such as asthma and immune disorders. Our findings demonstrate an association between in utero nicotine exposure and variable DNA methylation in fetal lung and placental tissues, suggesting a role for DNA methylation variation in the fetal origins of chronic diseases.     

Kinetic studies of the thermal decomposition of 2-chloroethylphosphonic Acid in aqueous solution

The decomposition of 2-chloroethylphosphonic acid in aqueous solution has been studied at pH values from 6 to 9 and at temperatures in the 30 to 55 C range. The rate of decomposition is estimated from the rate of formation of ethylene. The rate is proportional to the concentration of the phosphonate dianion and is independent of the hydroxyl ion concentration. The rate constant at 40 C is 1.9 × 10⁻⁴ sec⁻¹ and the activation energy is 29.8 kcal mol⁻¹. The rate of reaction is not affected significantly by the presence of potassium iodide or urea (substances which increase the rate of leaf abscission in trees sprayed by 2-chloroethylphosphonic acid). The rate decreases slightly in the presence of low concentrations of magnesium and calcium ions.     

Admixture-matched case-control study: a practical approach for genetic association studies in admixed populations

Case-control genetic association studies in admixed populations are known to be susceptible to genetic confounding due to population stratification. The transmission/disequilibrium test (TDT) approach can avoid this problem. However, the TDT is expensive and impractical for late-onset diseases. Case-control study designs, in which, cases and controls are matched by admixture, can be an appealing and a suitable alternative for genetic association studies in admixed populations. In this study, we applied this matching strategy when recruiting our African American participants in the Study of African American, Asthma, Genes and Environments. Group admixture in this cohort consists of 83% African ancestry and 17% European ancestry, which was consistent with reports from other studies. By carrying out several complementary analyses, our results show that there is a substructure in the cohort, but that the admixture distributions are almost identical in cases and controls, and also in cases only. We performed association tests for asthma-related traits with ancestry, and only found that FEV(1), a measure for baseline pulmonary function, was associated with ancestry after adjusting for socio-economic and environmental risk factors (P=0.01). We did not observe an excess of type I error rate in our association tests for ancestry informative markers and asthma-related phenotypes when ancestry was not adjusted in the analyses. Furthermore, using the association tests between genetic variants in a known asthma candidate gene, beta(2) adrenergic receptor (beta(2)AR) and DeltaFEF(25-75), an asthma-related phenotype, as an example, we demonstrated population stratification was not a confounder in our genetic association. Our present work demonstrates that admixture-matched case-control strategies can efficiently control population stratification confounding in admixed populations.     

Development of the AGREE II,part 2: assessment of validity of items and tools to support application

Background

We established a program of research to improve the development, reporting and evaluation of practice guidelines. We assessed the construct validity of the items and user’s manual in the β version of the AGREE II.

Methods

We designed guideline excerpts reflecting high-and low-quality guideline content for 21 of the 23 items in the tool. We designed two study packages so that one low-quality and one high-quality version of each item were randomly assigned to each package. We randomly assigned 30 participants to one of the two packages. Participants reviewed and rated the guideline content according to the instructions of the user’s manual and completed a survey assessing the manual.

Results

In all cases, content designed to be of high quality was rated higher than low-quality content; in 18 of 21 cases, the differences were significant (p < 0.05). The manual was rated by participants as appropriate, easy to use, and helpful in differentiating guidelines of varying quality, with all scores above the mid-point of the seven-point scale. Considerable feedback was offered on how the items and manual of the β-AGREE II could be improved.

Interpretation

The validity of the items was established and the user’s manual was rated as highly useful by users. We used these results and those of our study presented in part 1 to modify the items and user’s manual. We recommend AGREE II (available at www.agreetrust.org) as the revised standard for guideline development, reporting and evaluation.For clinical practice guidelines to achieve their full potential as tools to assist in clinical, policy-related and system-level decisions,^1–3 they need to be of high quality and developed using rigorous methods.⁴ Thus, strategies are required to facilitate the development and reporting of guidelines and tools able to distinguish guidelines of varying quality. The AGREE Collaboration (Appraisal of Guidelines, Research and Evaluation) was the first to create a generic tool to assess the process of guideline development and reporting,^5,6 and it quickly became the standard for guideline evaluation.⁷As with any new assessment tool, ongoing development of the instrument was required to improve its measurement properties and advance the guideline enterprise. The AGREE Next Steps Consortium undertook a program of research to achieve these goals and create the next version of the tool, the AGREE II.⁸ The consortium completed two studies (parts 1 and 2). In part 1, also reported in this issue,⁹ we conducted an analysis of the performance of the new seven-point response scale, explored the usefulness of the AGREE items, and systematically identified ways in which the items and supporting document could be improved.In part 2, reported here, we aimed to test the construct validity of the items and evaluate the new supporting documentation, which was intended to facilitate efficient and accurate application of the tool.The validity of the original AGREE instrument was explored in three ways.⁵ Appraisers’ attitudes about the instrument’s usefulness and the helpfulness of the supporting documents (i.e., a user guide and training manual) were used as measures of face validity. The construct validity of the instrument was tested using three core hypotheses for each of the six domains; 3 of the possible 18 tests were supported. In retrospect, whether the hypotheses were generalizable across contexts was somewhat questionable. Finally, to establish criterion validity, correlations between users’ overall global endorsement and quality ratings of individual items were calculated. Whether global endorsements were a reasonable proxy gold standard was somewhat questionable. Further, for both the construct validity and the criterion validity, guidelines chosen in these studies were nominated by members of the research team as representing a range of quality, creating significant risks of bias.Together, these findings and methodological limitations illustrated the need for additional work to test and establish the instrument’s validity. The most fundamental concept of construct validity, in particular, had not been yet addressed —are guidelines known to be of higher quality rated more favourably using the AGREE instrument than guidelines known to be of lower quality? In addition, no study to date has tested specifically whether the instructions for applying the tool are perceived to be appropriate, implementable, and helpful in differentiating among guidelines of varying quality. These perceptions are important components that contribute to the face validity of the tool.We tested two specific research questions in this study. First, do the items in β-AGREE II differentiate between guideline content of known, varying quality? Second, is the new user’s manual perceived by users as appropriate, easy to apply and helpful in differentiating good quality guidelines from poor quality guidelines?     

Analysis of extracellular vesicle miRNA profiles in heart failure

Extracellular vesicles (EVs) have recently emerged as an important carrier for various genetic materials including microRNAs (miRs). Growing evidences suggested that several miRs transported by EVs were particularly involved in modulating cardiac function. However, it has remained unclear what miRs are enriched in EVs and play an important role in the pathological condition. Therefore, we established the miR expression profiles in EVs from murine normal and failing hearts and consecutively identified substantially altered miRs. In addition, we have performed bioinformatics approach to predict potential cardiac outcomes through the identification of miR targets. Conclusively, we observed approximately 63% of predicted targets were validated with previous reports. Notably, the predicted targets by this approach were often involved in both beneficial and malicious signalling pathways, which may reflect heterogeneous cellular origins of EVs in tissues. Lastly, there has been an active debate on U6 whether it is a proper control. Through further analysis of EV miR profiles, miR‐676 was identified as a superior reference control due to its consistent and abundant expressions. In summary, our results contribute to identifying specific EV miRs for the potential therapeutic targets in heart failure and suggest that miR‐676 as a new reference control for the EV miR studies.     

Exposure to Inflammatory Cytokines IL-1β and TNFα Induces Compromise and Death of Astrocytes; Implications for Chronic Neuroinflammation

Background

Astrocytes have critical roles in the human CNS in health and disease. They provide trophic support to neurons and are innate-immune cells with keys roles during states-of-inflammation. In addition, they have integral functions associated with maintaining the integrity of the blood-brain barrier.

Methods

We have used cytometric bead arrays and xCELLigence technology to monitor the to monitor the inflammatory response profiles and astrocyte compromise in real-time under various inflammatory conditions. Responses were compared to a variety of inflammatory cytokines known to be released in the CNS during neuroinflammation. Astrocyte compromise measured by xCELLigence was confirmed using ATP measurements, cleaved caspase 3 expression, assessment of nuclear morphology and cell death.

Results

Inflammatory activation (IL-1β or TNFα) of astrocytes results in the transient production of key inflammatory mediators including IL-6, cell surface adhesion molecules, and various leukocyte chemoattractants. Following this phase, the NT2-astrocytes progressively become compromised, which is indicated by a loss of adhesion, appearance of apoptotic nuclei and reduction in ATP levels, followed by DEATH.The earliest signs of astrocyte compromise were observed between 24-48h post cytokine treatment. However, significant cell loss was not observed until at least 72h, where there was also an increase in the expression of cleaved-caspase 3. By 96 hours approximately 50% of the astrocytes were dead, with many of the remaining showing signs of compromise too. Numerous other inflammatory factors were tested, however these effects were only observed with IL-1β or TNFα treatment.

Conclusions

Here we reveal direct sensitivity to mediators of the inflammatory milieu. We highlight the power of xCELLigence technology for revealing the early progressive compromise of the astrocytes, which occurs 24-48 hours prior to substantive cell loss. Death induced by IL-1β or TNFα is relevant clinically as these two cytokines are produced by various peripheral tissues and by resident brain cells.     

Variants near FOXE1 are associated with hypothyroidism and other thyroid conditions: using electronic medical records for genome- and phenome-wide studies

We repurposed existing genotypes in DNA biobanks across the Electronic Medical Records and Genomics network to perform a genome-wide association study for primary hypothyroidism, the most common thyroid disease. Electronic selection algorithms incorporating billing codes, laboratory values, text queries, and medication records identified 1317 cases and 5053 controls of European ancestry within five electronic medical records (EMRs); the algorithms'' positive predictive values were 92.4% and 98.5% for cases and controls, respectively. Four single-nucleotide polymorphisms (SNPs) in linkage disequilibrium at 9q22 near FOXE1 were associated with hypothyroidism at genome-wide significance, the strongest being rs7850258 (odds ratio [OR] 0.74, p = 3.96 × 10⁻⁹). This association was replicated in a set of 263 cases and 1616 controls (OR = 0.60, p = 5.7 × 10⁻⁶). A phenome-wide association study (PheWAS) that was performed on this locus with 13,617 individuals and more than 200,000 patient-years of billing data identified associations with additional phenotypes: thyroiditis (OR = 0.58, p = 1.4 × 10⁻⁵), nodular (OR = 0.76, p = 3.1 × 10⁻⁵) and multinodular (OR = 0.69, p = 3.9 × 10⁻⁵) goiters, and thyrotoxicosis (OR = 0.76, p = 1.5 × 10⁻³), but not Graves disease (OR = 1.03, p = 0.82). Thyroid cancer, previously associated with this locus, was not significantly associated in the PheWAS (OR = 1.29, p = 0.09). The strongest association in the PheWAS was hypothyroidism (OR = 0.76, p = 2.7 × 10⁻¹³), which had an odds ratio that was nearly identical to that of the curated case-control population in the primary analysis, providing further validation of the PheWAS method. Our findings indicate that EMR-linked genomic data could allow discovery of genes associated with many diseases without additional genotyping cost.     

The significance of galectin-3 as a new basal cell marker in prostate cancer

Prostate cancer may originate from distinct cell types, resulting in the heterogeneity of this disease. Galectin-3 (Gal-3) and androgen receptor (AR) have been reported to play important roles in the progression of prostate cancer, and their heterogeneous expressions might be associated with different cancer subtypes. Our study found that in various prostate cancer cell lines Gal-3 expression was always opposite to AR expression and other luminal cell markers but consistent with basal cell markers including glutathione S-transferase-π and Bcl-2. This expression pattern was confirmed in human prostate cancer tissues. Our results also showed that prostate cancer cells positive with basal cell markers were more aggressive. Downregulation of Gal-3 expression resulted in increased apoptotic potential and decreased metastasis potential of prostate cancer cells. Our findings demonstrate for the first time that Gal-3 may serve as a new marker for basal characteristics of prostate cancer epithelium. This study helps us to better understand the heterogeneity of prostate cancer. The clinical significance of this study lies in the application of Gal-3 to distinguish prostate cancer subtypes and improve treatment efficacy with designed personalized therapy.