Evaluation of Cardiovascular Risk Factors in the Wistar Audiogenic Rat (WAR) Strain

Introduction

Risk factors for life-threatening cardiovascular events were evaluated in an experimental model of epilepsy, the Wistar Audiogenic Rat (WAR) strain.

Methods

We used long-term ECG recordings in conscious, one year old, WAR and Wistar control counterparts to evaluate spontaneous arrhythmias and heart rate variability, a tool to assess autonomic cardiac control. Ventricular function was also evaluated using the pressure-volume conductance system in anesthetized rats.

Results

Basal RR interval (RRi) was similar between WAR and Wistar rats (188±5 vs 199±6 ms). RRi variability strongly suggests that WAR present an autonomic imbalance with sympathetic overactivity, which is an isolated risk factor for cardiovascular events. Anesthetized WAR showed lower arterial pressure (92±3 vs 115±5 mmHg) and exhibited indices of systolic dysfunction, such as higher ventricle end-diastolic pressure (9.2±0.6 vs 5.6±1 mmHg) and volume (137±9 vs 68±9 μL) as well as lower rate of increase in ventricular pressure (5266±602 vs 7320±538 mmHg.s-1). Indices of diastolic cardiac function, such as lower rate of decrease in ventricular pressure (-5014±780 vs -7766±998 mmHg.s^-1) and a higher slope of the linear relationship between end-diastolic pressure and volume (0.078±0.011 vs 0.036±0.011 mmHg.μL), were also found in WAR as compared to Wistar control rats. Moreover, Wistar rats had 3 to 6 ventricular ectopic beats, whereas WAR showed 15 to 30 ectopic beats out of the 20,000 beats analyzed in each rat.

Conclusions

The autonomic imbalance observed previously at younger age is also present in aged WAR and, additionally, a cardiac dysfunction was also observed in the rats. These findings make this experimental model of epilepsy a valuable tool to study risk factors for cardiovascular events in epilepsy.     

Identification of Genes Whose Expression Profile Is Associated with Non-Progression towards AIDS Using eQTLs

Background

Many genome-wide association studies have been performed on progression towards the acquired immune deficiency syndrome (AIDS) and they mainly identified associations within the HLA loci. In this study, we demonstrate that the integration of biological information, namely gene expression data, can enhance the sensitivity of genetic studies to unravel new genetic associations relevant to AIDS.

Methods

We collated the biological information compiled from three databases of expression quantitative trait loci (eQTLs) involved in cells of the immune system. We derived a list of single nucleotide polymorphisms (SNPs) that are functional in that they correlate with differential expression of genes in at least two of the databases. We tested the association of those SNPs with AIDS progression in two cohorts, GRIV and ACS. Tests on permuted phenotypes of the GRIV and ACS cohorts or on randomised sets of equivalent SNPs allowed us to assess the statistical robustness of this method and to estimate the true positive rate.

Results

Eight genes were identified with high confidence (p = 0.001, rate of true positives 75%). Some of those genes had previously been linked with HIV infection. Notably, ENTPD4 belongs to the same family as CD39, whose expression has already been associated with AIDS progression; while DNAJB12 is part of the HSP90 pathway, which is involved in the control of HIV latency. Our study also drew our attention to lesser-known functions such as mitochondrial ribosomal proteins and a zinc finger protein, ZFP57, which could be central to the effectiveness of HIV infection. Interestingly, for six out of those eight genes, down-regulation is associated with non-progression, which makes them appealing targets to develop drugs against HIV.     

NGF Modulates trkANGFR/p75NTR in αSMA-Expressing Conjunctival Fibroblasts from Human Ocular Cicatricial Pemphigoid (OCP)

Objective

In a previous study, we reported the upregulation of Nerve Growth Factor (NGF) and trkA^NGFR expression in Ocular Cicatricial Pemphigoid (OCP), an inflammatory and remodeling eye disease. Herein, we hypothesize a potential NGF-driven mechanism on fibroblasts (FBs) during OCP remodeling events. To verify, human derived OCP-FBs were isolated and characterized either at baseline or after NGF exposure.

Materials and Methods

Conjunctival biopsies were obtained from 7 patients having OCP and 6 control subjects (cataract surgery). Both conjunctivas and primary FB cultures were characterised for αSMA, NGF and trkA^NGFR/p75^NTR expression. Subcultures were exposed to NGF and evaluated for αSMA, NGF, trkA^NGFR/p75^NTR expression as well as TGFβ1/IL4 release. For analysis, early and advanced subgroups were defined according to clinical parameters.

Results

OCP-conjunctivas showed αSMA-expressing FBs and high NGF levels. Advanced OCP-FBs showed higher αSMA expression associated with higher p75^NTR and lower trkA^NGFR expression, as compared to early counterparts. αSMA expression was in keeping with disease severity and correlated to p75^NTR. NGF exposure did not affect trkA^NGFR levels in early OCP-FBs while decreased both αSMA/p75^NTR expression and TGFβ1/IL4 release. These effects were not observed in advanced OCP-FBs.

Conclusions

Taken together, these data are suggestive for a NGF/p75^NTR task in the potential modulation of OCP fibrosis and encourages further studies to fully understand the underlying mechanism occurring in fibrosis. NGF/p75^NTR might be viewed as a potential therapeutic target.     

Involvement of the nitric oxide/CGMP/KATP pathway in antinociception induced by exercise in rats

AimsPhysical exercise is responsible for increasing the nociceptive threshold. The present study aimed to investigate the involvement of the nitric oxide/_CGMP/K_ATP pathway in antinociception induced by acute aerobic exercise (AAc) in rats.Main methodsWistar rats performed exercise in a rodent treadmill, according to an AAc protocol. The nociceptive threshold was measured by mechanical and thermal nociceptive tests (paw-withdrawal, tail-flick and face-flick). To investigate the involvement of the NO/_CGMP/K_ATP pathway the following nitric oxide synthase (NOS) unspecific and specific inhibitors were used: N-nitro-l-arginine (NOArg), Aminoguanidine, N⁵-(1-Iminoethyl)-l-ornithine dihydrocloride (L-NIO), N^ω-Propyl-l-arginine (L-NPA); guanylyl cyclase inhibitor, 1H-[1,2,4]oxidiazolo[4,3-a]quinoxalin-1-one (ODQ); and K_ATP channel blocker, Glybenclamide; all administered subcutaneously at a dose of 2 mg/kg 10 min before exercise started. Plasma and cerebrospinal fluid (CSF) nitrite levels were determined by spectrophotometry.Key findingsIn the paw-withdrawal, tail-flick and face-flick tests, the AAc protocol produced antinociception, which lasted for more than 15 min. This effect was significantly reversed (P < 0.05) by NOS specific and unspecific inhibitors, guanylyl cyclase inhibitor (ODQ) and K_ATP channel blocker (Glybenclamide). Acute exercise was also responsible for increasing nitrite levels in both plasma and cerebrospinal fluid.SignificanceTaken together, these results suggest that the NO/_CGMP/K_ATP pathway participates in antinociception induced by exercise.     

QTLs and candidate genes for desiccation and abscisic acid content in maize kernels

Background

Kernel moisture at harvest is an important trait since a low value is required to prevent unexpected early germination and ensure seed preservation. It is also well known that early germination occurs in viviparous mutants, which are impaired in abscisic acid (ABA) biosynthesis. To provide some insight into the genetic determinism of kernel desiccation in maize, quantitative trait loci (QTLs) were detected for traits related to kernel moisture and ABA content in both embryo and endosperm during kernel desiccation. In parallel, the expression and mapping of genes involved in kernel desiccation and ABA biosynthesis, were examined to detect candidate genes.

Results

The use of an intermated recombinant inbred line population allowed for precise QTL mapping. For 29 traits examined in an unreplicated time course trial of days after pollination, a total of 78 QTLs were detected, 43 being related to kernel desiccation, 15 to kernel weight and 20 to ABA content. Multi QTL models explained 35 to 50% of the phenotypic variation for traits related to water status, indicating a large genetic control amenable to breeding. Ten of the 20 loci controlling ABA content colocated with previously detected QTLs controlling water status and ABA content in water stressed leaves. Mapping of candidate genes associated with kernel desiccation and ABA biosynthesis revealed several colocations between genes with putative functions and QTLs. Parallel investigation via RT-PCR experiments showed that the expression patterns of the ABA-responsive Rab17 and Rab28 genes as well as the late embryogenesis abundant Emb5 and aquaporin genes were related to desiccation rate and parental allele effect. Database searches led to the identification and mapping of two zeaxanthin epoxidase (ZEP) and five novel 9-cis-epoxycarotenoid dioxygenase (NCED) related genes, both gene families being involved in ABA biosynthesis. The expression of these genes appeared independent in the embryo and endosperm and not correlated with ABA content in either tissue.

Conclusions

A high resolution QTL map for kernel desiccation and ABA content in embryo and endosperm showed several precise colocations between desiccation and ABA traits. Five new members of the maize NCED gene family and another maize ZEP gene were identified and mapped. Among all the identified candidates, aquaporins and members of the Responsive to ABA gene family appeared better candidates than NCEDs and ZEPs.     

S-nitrosoglutathione reductase affords protection against pathogens in Arabidopsis, both locally and systemically

Nitric oxide and S-nitrosothiols (SNOs) are widespread signaling molecules that regulate immunity in animals and plants. Levels of SNOs in vivo are controlled by nitric oxide synthesis (which in plants is achieved by different routes) and by S-nitrosoglutathione turnover, which is mainly performed by the S-nitrosoglutathione reductase (GSNOR). GSNOR is encoded by a single-copy gene in Arabidopsis (Arabidopsis thaliana; Martínez et al., 1996; Sakamoto et al., 2002). We report here that transgenic plants with decreased amounts of GSNOR (using antisense strategy) show enhanced basal resistance against Peronospora parasitica Noco2 (oomycete), which correlates with higher levels of intracellular SNOs and constitutive activation of the pathogenesis-related gene, PR-1. Moreover, systemic acquired resistance is impaired in plants overexpressing GSNOR and enhanced in the antisense plants, and this correlates with changes in the SNO content both in local and systemic leaves. We also show that GSNOR is localized in the phloem and, thus, could regulate systemic acquired resistance signal transport through the vascular system. Our data corroborate the data from other authors that GSNOR controls SNO in vivo levels, and shows that SNO content positively influences plant basal resistance and resistance-gene-mediated resistance as well. These data highlight GSNOR as an important and widely utilized component of resistance protein signaling networks conserved in animals and plants.     

Intestinal epithelial cells from inflammatory bowel disease patients preferentially stimulate CD4+ T cells to proliferate and secrete interferon-gamma

Previous studies have suggested that intestinal epithelial cells (IECs) have the capacity to function as nonprofessional antigen presenting cells that in the normal state preferentially activate CD8+ T cells. However, under pathological conditions, such as those found in inflammatory bowel disease (IBD), persistent activation of CD4+ T cells is seen. The aim of this study was to determine whether the IBD IECs contribute to CD4+ T cell activation. Freshly isolated human IECs were obtained from surgical specimens of patients with or without IBD and cocultured with autologous or allogeneic peripheral blood T lymphocytes. Cocultures of normal T cells and IECs derived from IBD patients resulted in the preferential activation of CD4+ T cell proliferation that was associated with significant IFN-gamma, but not IL-2, secretion. Cytokine secretion and CD4+ T cell proliferation was inhibited by pretreatment of the IBD IECs with the anti-DR MAb L243. In contrast, normal IECs stimulated the proliferation and cytokine secretion by CD4+ T cells to a significantly lesser degree than IBD IECs. Furthermore, blockade of human leukocyte antigen-DR had a lesser effect in the normal IEC-CD4+ T cell cocultures. We conclude that IECs can contribute to the ongoing CD4+ T cell activation seen in IBD. We suggest that the apparent differences between the secreted levels of IFN-gamma indicate that it may play a dual role in intestinal homeostasis, in which low levels contribute to physiological inflammation whereas higher levels are associated with an uncontrolled inflammatory state.     

Rate of increase in circulating IL-7 and loss of IL-7Ralpha expression differ in HIV-1 and HIV-2 infections: two lymphopenic diseases with similar hyperimmune activation but distinct outcomes

IL-7 is a nonredundant cytokine for T cell homeostasis. Circulating IL-7 levels increase in lymphopenic clinical settings, including HIV-1 infection. HIV-2 infection is considered a "natural" model of attenuated HIV disease given its much slower rate of CD4 decline than HIV-1 and limited impact on the survival of the majority of infected adults. We compared untreated HIV-1- and HIV-2-infected patients and found that the HIV-2 cohort demonstrated a delayed increase in IL-7 levels during the progressive depletion of circulating CD4 T cells as well as a dissociation between the acquisition of markers of T cell effector differentiation and the loss of IL-7Ralpha expression. This comparison of two persistent infections associated with progressive CD4 depletion and immune activation demonstrates that a better prognosis is not necessarily associated with higher levels of IL-7. Moreover, the delayed increase in IL-7 coupled with sustained expression of IL-7Ralpha suggests a maximization of available resources in HIV-2. The observation that increased IL-7 levels early in HIV-1 infection were unable to reduce the rate of CD4 loss and the impaired expression of the IL-7Ralpha irrespective of the state of cell differentiation raises concerns regarding the use of IL-7 therapy in HIV-1 infection.