OBJECTIVETo assess the clinical efficacy of nutritional amounts of grape polyphenols (PPs) in counteracting the metabolic alterations of high-fructose diet, including oxidative stress and insulin resistance (IR), in healthy volunteers with high metabolic risk.RESEARCH DESIGN AND METHODSThirty-eight healthy overweight/obese first-degree relatives of type 2 diabetic patients (18 men and 20 women) were randomized in a double-blind controlled trial between a grape PP (2 g/day) and a placebo (PCB) group. Subjects were investigated at baseline and after 8 and 9 weeks of supplementation, the last 6 days of which they all received 3 g/kg fat-free mass/day of fructose. The primary end point was the protective effect of grape PPs on fructose-induced IR.RESULTSIn the PCB group, fructose induced 1) a 20% decrease in hepatic insulin sensitivity index (P < 0.05) and an 11% decrease in glucose infusion rate (P < 0.05) as evaluated during a two-step hyperinsulinemic-euglycemic clamp, 2) an increase in systemic (urinary F2-isoprostanes) and muscle (thiobarbituric acid–reactive substances and protein carbonylation) oxidative stress (P < 0.05), and 3) a downregulation of mitochondrial genes and decreased mitochondrial respiration (P < 0.05). All the deleterious effects of fructose were fully blunted by grape PP supplementation. Antioxidative defenses, inflammatory markers, and main adipokines were affected neither by fructose nor by grape PPs.CONCLUSIONSA natural mixture of grape PPs at nutritional doses efficiently prevents fructose-induced oxidative stress and IR. The current interest in grape PP ingredients and products by the global food and nutrition industries could well make them a stepping-stone of preventive nutrition.

Facioscapulohumeral muscular dystrophy (FSHD), an autosomal dominant neuromuscular disorder, has been causally related to deletion of tandemly arrayed 3.3 kb repeats (D4Z4) on chromosome 4q35. Although increased expression of several 4q35 genes has been reported, two recent studies dispute this, finding no significant changes in the transcriptional level of any of the 4q35 genes, among which is the heart and muscle-specific isoform of the adenine nucleotide translocator (ANT1). We found markedly increased levels of ANT1 protein in both unaffected and affected FSHD muscles in comparison to control healthy muscles. Comparative protein expression analysis between healthy, Duchenne muscular dystrophy, and FSHD muscle shows that proteins involved in mitochondrial function and protection from oxidative stress are also reproducibly and specifically modified in all FSHD muscles, including clinically unaffected muscles. Increased ANT1 expression and mitochondrial dysfunction may thus be initial events in FSHD pathogenesis and represent potential therapeutic targets.

The endoribonuclease L (RNase L) is the effector of the 2-5A system, a major enzymatic pathway involved in the molecular mechanism of interferons (IFN). RNase L is a very unusual nuclease with a complex mechanism of regulation. It is a latent enzyme, expressed in nearly every mammalian cell type. Its activation requires its binding to a small oligonucleotide, 2-5A. 2-5A is a series of unique 5′-triphosphorylated oligoadenylates with 2′-5′ phosphodiester bonds. By regulating viral and cellular RNA expression, RNase L plays an important role in the antiviral and antiproliferative activities of IFN and contributes to innate immunity and cell metabolism. The 2-5A/RNase L pathway is implicated in mediating apoptosis in response to viral infections and to several types of external stimuli. Several recent studies have suggested that RNase L could have a role in cancer biology and evidence of a tumor suppressor function of RNase L has emerged from studies on the genetics of hereditary prostate cancer. KeywordsInterferon; RNase L; RNA expression; apoptosis; prostate; virus; cancer I) IntroductionThe endoribonuclease L (RNase L) is the effector of the 2-5A system, a major enzymatic pathway regulated by interferons (IFN) [1] (Figure 1). The 2-5A system is one of the two antiviral pathways induced by IFN and activated by double stranded RNA (dsRNA), the other is mediated by the dsRNA dependent protein kinase (PKR) [2]. RNase L is a very unusual nuclease. It is a latent enzyme, expressed in nearly every mammalian cell type. Its activation requires its binding to a small oligonucleotide, 2-5A ( Figure 1). 2-5A itself is very unusual, consisting of a series of 5′-triphosphorylated oligoadenylates with 2′-5′ phosphodiester bonds in contrast to the 3′-5′ linkages found in RNA and DNA. The initial and essential observation was made by Ian Kerr's group in 1974 reporting an IFN-induced increase in the sensitivity of protein synthesis to inhibition by dsRNA [3]. Peter Lengyel's group observed increased nuclease activity in extracts of interferon treated cells incubated with dsRNA [4,5]. The identification by Ian Kerr's group of the activators of this nuclease, 2-5A [6] and of the enzyme responsible for their synthesis, the 2-5A-synthetase [7][8][9], led to the discovery of the 2-5A pathway. Clemens and Williams directly demonstrated a nuclease, now recognized as RNase Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. (Figure 2). The N-terminal domain could be considered as the regulatory domain of RNase L. It is composed of eight complete and one partial ankyrin motifs (R1-R9). Two wal...

The 2-5 oligoadenylate (2-5A)/RNase L pathway is one of the enzymatic pathways induced by interferon. RNase L is a latent endoribonuclease which is activated by 2-5A and inhibited by a specific protein known as RLI (RNase L inhibitor). This system has an important role in regulating viral infection. Additionally, variations in RNase L activity have been observed during cell growth and differentiation but the significance of the 2-5A/RNase L/RLI pathway in these latter processes is not known. To determine the roles of RNase L and RLI in muscle differentiation, C2 mouse myoblasts were transfected with sense and antisense RLI cDNA constructs. Importantly, the overexpression of RLI in C2 cells was associated with diminished RNase L activity, an increased level of MyoD mRNA, and accelerated kinetics of muscle differentiation. Inversely, transfection of the RLI antisense construct was associated with increased RNase L activity, a diminished level of MyoD mRNA, and delayed differentiation. In agreement with these data, MyoD mRNA levels were also decreased in C2 cells transfected with an inducible RNase L construct. The effect of RNase L activity on MyoD mRNA levels was relatively specific because expression of several other mRNAs was not altered in C2 transfectants. Therefore, RNase L is directly involved in myoblast differentiation, probably through its role in regulating MyoD stability. This is the first identification of a potential mRNA target for RNase L.The 2Ј-5Ј oligoadenylate (2-5A)/RNase L system is an interferon (IFN)-inducible RNA degradation pathway which is responsible for many of the antiviral and antiproliferative effects of IFNs (37, 41).The 2-5A pathway is composed of at least three types of enzymatic activities: 2-5A-synthetase, 2-5A-degrading enzymes, and RNase L. 2-5A, an oligoadenylate with 2Ј-5Ј phosphodiester bonds, activates RNase L (53), a latent endoribonuclease. Upon activation, RNase L cleaves mRNAs 3Ј of UpNp sequences, thus leading to the inhibition of protein synthesis (14,21).The activity of RNase L was originally thought to be modulated solely by the concentration of the 2-5A activator (11,21). Moreover, we have previously established that RNase L activity can also be regulated by RLI (RNase L inhibitor), a protein inhibitor (5). Overexpression of the RLI cDNA in HeLa cells results in the inhibition of the IFN-activated 2-5A pathway. RLI is induced by viruses such as encephalomyocarditis virus (EMCV) and human immunodeficiency virus (HIV), causing an inhibition of the 2-5A/RNase L system (27, 28). The role of the 2-5A/RNase L pathway in the selective reduction of viral mRNA during EMCV and HIV infection has been demonstrated elsewhere (16,25,27).Variations in intracellular 2-5A and 2-5A-synthetase levels have been observed during cell growth and differentiation even in the absence of exogenous IFN treatment. Indeed, expression of IFN-inducible proteins, such as 2-5A-synthetase, doublestanded RNA-activated protein kinase (PKR), and p202 (a member of the "200 family" of murine proteins) h...

The 2-5A/RNase L system is considered as a central pathway of interferon (IFN) action and could possibly play a more general physiological role as for instance in the regulation of RNA stability in mammalian cells. We describe here the expression cloning and initial characterization of RLI (for RNase L inhibitor), a new type of endoribonuclease inhibitor. RLI cDNA codes for a 68-kDa polypeptide whose expression is not regulated by IFN. Its expression in reticulocyte extracts antagonizes the 2-5A binding ability and the nuclease activity of endogenous RNase L or the cloned 2DR polypeptide. The inhibition requires the association of RLI with the nuclease and is dependent on the ratio between the two proteins. Likewise RLI is coimmunoprecipitated with the RNase L complex by a nuclease-specific antibody. RLI does not lead to 2-5A degradation or to irreversible modification of RNase L. The overexpression of RLI in stably transfected HeLa cells inhibits the antiviral activity of IFN on encephalomyocarditis virus but not on vesicular stomatitis virus. RLI therefore appears as the first described and potentially important mediator of the 2-5A/RNase L pathway.

Rupatadine significantly relieves symptoms of PER, providing a rapid onset of action and maintains its effects over a long period of 12-weeks.

H19 is a paternally imprinted gene whose expression produces a 2.4 kb RNA in most tissues during development and in mammalian myoblastic cell lines upon di erentiation. Deletion of the active maternal allele of H19 and its¯anking regions in the mouse leads to biallelic methylation and loss of imprinting of the neighbouring Igf2 gene. The function of H19 RNA remains unknown and, although polysome-associated, the absence of a conserved open reading frame suggests that it does not encode a protein product. We describe a novel post-transcriptional regulation of H19 gene expression which, in spite of this lack of coding capacity, is dependent on translational activity. We show that stabilization of the RNA is solely responsible for its accumulation during in vitro muscle cell di erentiation. This conclusion is based on the ®nding that inhibition of protein synthesis results in a dramatic destabilization of H19 RNA in proliferating mouse C2C12 myoblastic cells but not in di erentiated cells, and on run-on experiments which showed that the rate of transcription of H19 RNA remains constant during muscle cell di erentiation. This mechanism could also be involved in H19 gene expression during mouse development in addition to its transcriptional activation which we have shown to occur.

The antiviral and antiproliferative effects of interferons are mediated in part by the 2'-5' oligoadenylate-RNase L RNA decay pathway. RNase L is an endoribonuclease that requires 2'-5' oligoadenylates to cleave single-stranded RNA. In this report we present evidence demonstrating a role for RNase L in translation. We identify and characterize the human translation termination factor eRF3/GSPT1 as an interacting partner of RNase L. We show that interaction of eRF3 with RNase L leads to both increased translation readthrough efficiency at premature termination codons and increased +1 frameshift efficiency at the antizyme +1 frameshift site. On the basis of our results, we present a model describing how RNase L is involved in regulating gene expression by modulating the translation termination process.