Human Parechovirus and Enterovirus Initiate Divergent Innate Immune Responses in the CNS: Pathogenic and Diagnostic Implications

The picornaviruses human parechovirus (HPeV) and enterovirus (EV) cause a wide range of diseases, including CNS infections, which can be severe and potentially fatal. EV causes most cases of pediatric meningoencephalitis worldwide, and HPeV type 3 (HPeV3) is the most common cause of viral meningitis in young infants. Each year in the United States, there are over 75,000 cases of aseptic meningitis. Despite reassuring short-term outcomes, negative neurodevelopmental sequalae are increasingly associated with HPeV and EV. The pathogenesis and severity of HPeV and EV infections are undoubtedly linked to the innate and adaptive immune responses elicited by these viruses. Until this work, the innate immune response mounted against HPeV was largely unknown. Pattern recognition receptors in the CNS, including a number of Toll-like receptors located in different cells and subcellular compartments, detect invading pathogens and cause the release of cytokines and chemokines almost immediately into the CSF compartment at measurable levels. Essentially, this allows for determination of an amplified, infectious agent-specific pattern. These virus specific patterns of innate immune activation may provide insight into the pathogenesis of the corresponding disease states. Also, since these infections have similar clinical presentations, the immune profiles may be useful for rapid pathogen diagnosis in the clinical setting

Acute ingestion of a novel whey-derived peptide improves vascular endothelial responses in healthy individuals: a randomized, placebo controlled trial

<p>Abstract</p> <p>Background</p> <p>Whey protein is a potential source of bioactive peptides. Based on findings from <it>in vitro </it>experiments indicating a novel whey derived peptide (NOP-47) increased endothelial nitric oxide synthesis, we tested its effects on vascular function in humans.</p> <p>Methods</p> <p>A randomized, placebo-controlled, crossover study design was used. Healthy men (n = 10) and women (n = 10) (25 ± 5 y, BMI = 24.3 ± 2.3 kg/m²) participated in two vascular testing days each preceded by 2 wk of supplementation with a single dose of 5 g/day of a novel whey-derived peptide (NOP-47) or placebo. There was a 2 wk washout period between trials. After 2 wk of supplementation, vascular function in the forearm and circulating oxidative stress and inflammatory related biomarkers were measured serially for 2 h after ingestion of 5 g of NOP-47 or placebo. Macrovascular and microvascular function were assessed using brachial artery flow mediated dilation (FMD) and venous occlusion strain gauge plethysmography.</p> <p>Results</p> <p>Baseline peak FMD was not different for Placebo (7.7%) and NOP-47 (7.8%). Placebo had no effect on FMD at 30, 60, and 90 min post-ingestion (7.5%, 7.2%, and 7.6%, respectively) whereas NOP-47 significantly improved FMD responses at these respective postprandial time points compared to baseline (8.9%, 9.9%, and 9.0%; <it>P </it>< 0.0001 for time × trial interaction). Baseline reactive hyperemia forearm blood flow was not different for placebo (27.2 ± 7.2%/min) and NOP-47 (27.3 ± 7.6%/min). Hyperemia blood flow measured 120 min post-ingestion (27.2 ± 7.8%/min) was unaffected by placebo whereas NOP-47 significantly increased hyperemia compared to baseline (29.9 ± 7.8%/min; <it>P </it>= 0.008 for time × trial interaction). Plasma myeloperoxidase was increased transiently by both NOP-47 and placebo, but there were no changes in markers inflammation. Plasma total nitrites/nitrates significantly decreased over the 2 hr post-ingestion period and were lower at 120 min after placebo (-25%) compared to NOP-47 (-18%).</p> <p>Conclusion</p> <p>These findings indicate that supplementation with a novel whey-derived peptide in healthy individuals improves vascular function.</p

Limited Effect of Dietary Saturated Fat on Plasma Saturated Fat in the Context of a Low Carbohydrate Diet

We recently showed that a hypocaloric carbohydrate restricted diet (CRD) had two striking effects: (1) a reduction in plasma saturated fatty acids (SFA) despite higher intake than a low fat diet, and (2) a decrease in inflammation despite a significant increase in arachidonic acid (ARA). Here we extend these findings in 8 weight stable men who were fed two 6-week CRD (12%en carbohydrate) varying in quality of fat. One CRD emphasized SFA (CRD-SFA, 86 g/d SFA) and the other, unsaturated fat (CRD-UFA, 47 g SFA/d). All foods were provided to subjects. Both CRD decreased serum triacylglycerol (TAG) and insulin, and increased LDL-C particle size. The CRD-UFA significantly decreased plasma TAG SFA (27.48 ± 2.89 mol%) compared to baseline (31.06 ± 4.26 mol%). Plasma TAG SFA, however, remained unchanged in the CRD-SFA (33.14 ± 3.49 mol%) despite a doubling in SFA intake. Both CRD significantly reduced plasma palmitoleic acid (16:1n-7) indicating decreased de novo lipogenesis. CRD-SFA significantly increased plasma phospholipid ARA content, while CRD-UFA significantly increased EPA and DHA. Urine 8-iso PGF2α, a free radical-catalyzed product of ARA, was significantly lower than baseline following CRD-UFA (−32%). There was a significant inverse correlation between changes in urine 8-iso PGF2α and PL ARA on both CRD (r = −0.82 CRD-SFA; r = −0.62 CRD-UFA). These findings are consistent with the concept that dietary saturated fat is efficiently metabolized in the presence of low carbohydrate, and that a CRD results in better preservation of plasma ARA

HTLV-1 Tax Mediated Downregulation of miRNAs Associated with Chromatin Remodeling Factors in T Cells with Stably Integrated Viral Promoter

RNA interference (RNAi) is a natural cellular mechanism to silence gene expression and is predominantly mediated by microRNAs (miRNAs) that target messenger RNA. Viruses can manipulate the cellular processes necessary for their replication by targeting the host RNAi machinery. This study explores the effect of human T-cell leukemia virus type 1 (HTLV-1) transactivating protein Tax on the RNAi pathway in the context of a chromosomally integrated viral long terminal repeat (LTR) using a CD4+ T-cell line, Jurkat. Transcription factor profiling of the HTLV-1 LTR stably integrated T-cell clone transfected with Tax demonstrates increased activation of substrates and factors associated with chromatin remodeling complexes. Using a miRNA microarray and bioinformatics experimental approach, Tax was also shown to downregulate the expression of miRNAs associated with the translational regulation of factors required for chromatin remodeling. These observations were validated with selected miRNAs and an HTLV-1 infected T cells line, MT-2. miR-149 and miR-873 were found to be capable of directly targeting p300 and p/CAF, chromatin remodeling factors known to play critical role in HTLV-1 pathogenesis. Overall, these results are first in line establishing HTLV-1/Tax-miRNA-chromatin concept and open new avenues toward understanding retroviral latency and/or replication in a given cell type

Cancer, Caveolin-1, and Non-Coding RNAs: Novel Insights into Tumor Biology

Cancer may be thought of as the manifestation of a number of dysregulated biochemical processes that ultimately lead to a population of cells demonstrating uncontrolled proliferation, limitless replicative potential, resistance to programmed death, loss of differentiated phenotypes, and capacity for invasion into surrounding tissues. Given their heterogeneous nature, the oncogenic steps towards the development of these attributes are highly variable and often unique to specific cancers and tissue types. This work aims to characterize the roles of two different cellular factors with emerging relevance to cancer onset and progression. Specifically, the role of caveolin-1, a transmembrane scaffolding protein, is explored in the context of malignant glioma, and further, the role of microRNAs (miRNAs) are characterized in relation to the ability to post-transcriptionally regulate DNA repair pathways as well as miRNA regulatory networks in an in vitro model of pancreatic cancer. The findings presented here suggest that caveolin-1 acts as an endogenous tumor suppressor in glioma by silencing a number of a number of oncogenic signaling mechanisms related to MAP-kinase and PI3K/AKT pathways both in vitro and in vivo through the use of microarray and protein expression profiling methods. Additionally, forced upregulation of caveolin-1 in a cell line model of glioma results in increased sensitivity to treatment with the commonly used chemotherapeutic agent, temozolomide. Separately, computational approaches towards the identification of non-standard miRNA interactions yielded a novel target site for the miR-15/107 family of miRNAs on the BRCA1 transcript, a critical factor in DNA repair machinery commonly dysregulated in familial cancers. Lastly, argonaute CLIP-seq performed in cell line models of both normal and cancerous pancreatic epithelium demonstrates a highly dynamic repertoire of miRNA targets originating from many non-coding genomic loci. Together, these results highlight novel avenues for further exploration as it relates to the molecular mechanisms of oncogenesis in brain, pancreatic, and other cancers

Post-transcriptional regulation of BRCA2 through interactions with miR-19a and miR-19b

Breast cancer type 2, early onset susceptibility gene (BRCA2) is a major component of the homologous recombination DNA repair pathway. It acts as a tumor suppressor whose function is often lost in cancers. Patients with specific mutations in the BRCA2 gene often display discrete clinical, histopathological and molecular features. However, a subset of sporadic cancers has wild type BRCA2 and display defects in the Homology-Directed Repair (HDR) pathway, which is the hallmark of ‘BRCAness’. The mechanisms by which BRCAness arises are not fully understood but post-transcriptional regulation of BRCA2 gene expression by microRNAs (miRNAs) may contribute to this phenotype. Here, we examine the post-transcriptional effects that some members of the six-miRNA cluster known as the miR-17/92 cluster have on the abundance of BRCA2’s messenger RNA (mRNA) and protein. We discuss two interactions involving the miR-19a and miR-19b members of the cluster and the 3´UTR of BRCA2’s mRNA. We investigated these miRNA:mRNA interactions in fifteen cell lines derived from pancreatic, breast, colon, and kidney tissue. We show that over-expression of these two miRNAs results in a concomitant decrease of BRCA2’s mRNA and protein expression in a subset of the tested cell lines. Additionally, using luciferase reporter assays we identified direct interactions between miR-19a/miR-19b and a miRNA response element (MRE) in BRCA2’s 3´UTR. Our results suggest that BRCA2 is subject to a complex post-transcriptional regulatory program that has specific dependencies on the genetic and phenotypic background of cell types

DC-SIGN Mediates Cell-Free Infection and Transmission of Human T-Cell Lymphotropic Virus Type 1 by Dendritic Cells▿

Despite the susceptibility of dendritic cells (DCs) to human T-cell lymphotropic virus type 1 (HTLV-1) infection and the defined role of these cells in disease pathogenesis, the mechanisms of viral binding to DCs have not been fully delineated. Recently, a glucose transporter, GLUT-1, heparan sulfate proteoglycans (HSPGs), and neuropilin-1 (NRP-1) were demonstrated to facilitate HTLV-1 entry into T cells. DCs express their own array of antigen receptors, the most important being the DC-specific intercellular adhesion molecule-3 (ICAM-3)-grabbing nonintegrin (DC-SIGN) with respect to retrovirus binding. Consequently, the role of DC-SIGN and other HTLV-1 attachment factors was analyzed in viral binding, transmission, and productive infection using monocyte-derived DCs (MDDCs), blood myeloid DCs, and B-cell lines expressing DC-SIGN. The relative expression of DC-SIGN, GLUT-1, HSPGs, and NRP-1 first was examined on both DCs and B-cell lines. Although the inhibition of these molecules reduced viral binding, HTLV-1 transmission from DCs to T cells was mediated primarily by DC-SIGN. DC-SIGN also was shown to play a role in the infection of MDDCs as well as model B-cell lines. The HTLV-1 infection of MDDCs also was achieved in blood myeloid DCs following the enhancement of virus-induced interleukin-4 production and subsequent DC-SIGN expression in this cell population. This study represents the first comprehensive analysis of potential HTLV-1 receptors on DCs and strongly suggests that DC-SIGN plays a critical role in HTLV-1 binding, transmission, and infection, thereby providing an attractive target for the development of antiretroviral therapeutics and microbicides

Transcription factor profiling of T cells containing stably integrated or transiently transfected HTLV-1 LTR.

*<p> <b>Substrates for histone acetyltransferases (HATs) - p300, P/CAF, TAF1.</b></p>**<p> <b>Nuclear receptor (NR) family.</b></p><p>List of various cellular transcription factors that were differentially up- or downregulated in case of stably integrated or transiently transfected viral LTR.</p