Pro-inflammatory cytokines in acute coronary syndromes: from bench to bedside

Cytokines are produced in a variety of tissues and regulate the expression of a number of inflammatory molecules, leading to destabilization and finally rupture of vulnerable atheromatic plaques. They also participate in the pathophysiology of acute coronary syndromes (ACS) by direct effects on myocardial contractility and apoptosis. At a clinical level, circulating cytokines have a prognostic role since they are useful markers predicting future coronary events in patients with advanced atherosclerosis and in patients after ACS.     

Versatile regulation of cytosolic Ca2+ by vanilloid receptor I in rat dorsal root ganglion neurons

Analysis of small dorsal root ganglion (DRG) neurons revealed novel functions for vanilloid receptor 1 (VR1) in the regulation of cytosolic Ca(2+). The VR1 agonist capsaicin induced Ca(2+) mobilization from intracellular stores in the absence of extracellular Ca(2+), and this release was inhibited by the VR1 antagonist capsazepine but was unaffected by the phospholipase C inhibitor xestospongins, indicating that Ca(2+) mobilization was dependent on capsaicin receptor binding and was not due to intracellular inositol-1,4,5-trisphosphate generation. Confocal microscopy revealed extensive expression of VR1 on endoplasmic reticulum, consistent with VR1 operating as a Ca(2+) release receptor. The main part of the capsaicin-releasable Ca(2+) store was insensitive to thapsigargin, a selective endoplasmic reticulum Ca(2+)-ATPase inhibitor, suggesting that VR1 might be predominantly localized to a thapsigargin-insensitive endoplasmic reticulum Ca(2+) store. In addition, VR1 was observed to behave as a store-operated Ca(2+) influx channel. In DRG neurons, capsazepine attenuated Ca(2+) influx following thapsigargin-induced Ca(2+) store depletion and inhibited thapsigargin-induced inward currents. Conversely, transfected HEK-293 cells expressing VR1 showed enhanced Ca(2+) influx and inward currents following Ca(2+) store depletion. Combined data support topographical and functional diversity for VR1 in the regulation of cytosolic Ca(2+) with the plasma membrane-associated form behaving as a store-operated Ca(2+) influx channel and endoplasmic reticulum-associated VR1 possibly functioning as a Ca(2+) release receptor in sensory neurons.     

Molecular Basis of the Size Polymorphism of the First Intron of the<Emphasis Type="Italic">Adh-1</Emphasis> Gene of the Mediterranean Fruit Fly, <Emphasis Type="Italic">Ceratitis capitata</Emphasis>

The first intron of the gene encoding one of the alcohol dehydrogenase isoenzymes (ADH-1) in Ceratitis capitata is highly polymorphic in size. Five size variants of this intron were isolated from different strains and populations and characterized. Restriction map and sequence analysis showed that the intron size polymorphism is due to the presence or absence of (a) a copy of a defective mariner-like element, postdoc; (b) an 550-bp 3 indel which exhibits no similarity to any known sequence; and (c) a central duplication of 704 bp consisting of part of the 3 end of the postdoc element, the region between postdoc and the 3 indel, and the first 20 bp of the 3 indel. The homologous Adh-1 intron was amplified from the congeneric species, Ceratitis rosa, in order to obtain an outgroup for comparative and phylogenetic analyses. The C. rosa introns were polymorphic in size, ranging from about 1100 to 2000 bp, the major difference between them being the presence or absence of a mariner-like element Crmar2, unrelated to the postdoc element. Phylogenetic analysis suggests that the shorter intron variants in C. capitata may represent the ancestral form of the intron, the longest variants apparently being the most recent.     

Simple sleep questions can predict 12-year mortality in a rural population

Sleep and Biological Rhythms - There is apt evidence in favor of a significant association between sleep and mortality. So far, most studies examine sleep problems using comprehensive,...     

PECAM-directed delivery of catalase to endothelium protects against pulmonary vascular oxidative stress

Targeted delivery of drugs to vascular endothelium promises more effective and specific therapies in many disease conditions, including acute lung injury (ALI). This study evaluates the therapeutic effect of drug targeting to PECAM (platelet/endothelial cell adhesion molecule-1) in vivo in the context of pulmonary oxidative stress. Endothelial injury by reactive oxygen species (e.g., H2O2) is involved in many disease conditions, including ALI/acute respiratory distress syndrome and ischemia-reperfusion. To optimize delivery of antioxidant therapeutics, we conjugated catalase with PECAM antibodies and tested properties of anti-PECAM/catalase conjugates in cell culture and mice. Anti-PECAM/catalase, but not an IgG/catalase counterpart, bound specifically to PECAM-expressing cells, augmented their H2O2-degrading capacity, and protected them against H2O2 toxicity. Anti-PECAM/catalase, but not IgG/catalase, rapidly accumulated in the lungs after intravenous injection in mice, where it was confined to the pulmonary endothelium. To test its protective effect, we employed a murine model of oxidative lung injury induced by glucose oxidase coupled with thrombomodulin antibody (anti-TM/GOX). After intravenous injection in mice, anti-TM/GOX binds to pulmonary endothelium and produces H2O2, which causes lung injury and 100% lethality within 7 h. Coinjection of anti-PECAM/catalase protected against anti-TM/GOX-induced pulmonary oxidative stress, injury, and lethality, whereas polyethylene glycol catalase or IgG/catalase conjugates afforded only marginal protective effects. This result validates vascular immunotargeting as a prospective strategy for therapeutic interventions aimed at immediate protective effects, e.g., for augmentation of antioxidant defense in the pulmonary endothelium and treatment of ALI.     

The kynurenine pathway modulates neurodegeneration in a Drosophila model of Huntington's disease

Neuroactive metabolites of the kynurenine pathway (KP) of tryptophan degradation have been implicated in the pathophysiology of neurodegenerative disorders, including Huntington's disease (HD) [1]. A central hallmark of HD is neurodegeneration caused by a polyglutamine expansion in the huntingtin (htt) protein [2]. Here we exploit a transgenic Drosophila melanogaster model of HD to interrogate the therapeutic potential of KP manipulation. We observe that genetic and pharmacological inhibition of kynurenine 3-monooxygenase (KMO) increases levels of the neuroprotective metabolite kynurenic acid (KYNA) relative to the neurotoxic metabolite 3-hydroxykynurenine (3-HK) and ameliorates neurodegeneration. We also find that genetic inhibition of tryptophan 2,3-dioxygenase (TDO), the first and rate-limiting step in the pathway, leads to a similar neuroprotective shift toward KYNA synthesis. Importantly, we demonstrate that the feeding of KYNA and 3-HK to HD model flies directly modulates neurodegeneration, underscoring the causative nature of these metabolites. This study provides the first genetic evidence that inhibition of KMO and TDO activity protects against neurodegenerative disease in an animal model, indicating that strategies targeted?at?two key points within the KP may have therapeutic relevance in HD, and possibly other neurodegenerative disorders.     

Decorin antagonizes IGF receptor I (IGF-IR) function by interfering with IGF-IR activity and attenuating downstream signaling

We have recently discovered that the insulin-like growth factor receptor I (IGF-IR) is up-regulated in human invasive bladder cancer and promotes migration and invasion of transformed urothelial cells. The proteoglycan decorin, a key component of the tumor stroma, can positively regulate the IGF-IR system in normal cells. However, there are no available data on the role of decorin in modulating IGF-IR activity in transformed cells or in tumor models. Here we show that the expression of decorin inversely correlated with IGF-IR expression in low and high grade bladder cancers (n = 20 each). Decorin bound with high affinity IGF-IR and IGF-I at distinct sites and negatively regulated IGF-IR activity in urothelial cancer cells. Nanomolar concentrations of decorin promoted down-regulation of IRS-1, one of the critical proteins of the IGF-IR pathway, and attenuated IGF-I-dependent activation of Akt and MAPK. This led to decorin-evoked inhibition of migration and invasion upon IGF-I stimulation. Notably, decorin did not cause down-regulation of the IGF-IR in bladder, breast, and squamous carcinoma cells. This indicates that decorin action on the IGF-IR differs from its known activity on other receptor tyrosine kinases such as the EGF receptor and Met. Our results provide a novel mechanism for decorin in negatively modulating both IGF-I and its receptor. Thus, decorin loss may contribute to increased IGF-IR activity in the progression of bladder cancer and perhaps other forms of cancer where IGF-IR plays a role.