Glucocorticoid-induced tumor necrosis factor receptor is a p21Cip1/WAF1 transcriptional target conferring resistance of keratinocytes to UV light-induced apoptosis.

Glucocorticoid-induced tumor necrosis factor receptor (GITR) is a member of the tumor necrosis factor receptor superfamily, is expressed in T lymphocytes, and exerts an anti-apoptotic function in these cells. We reported that GITR is also highly expressed in the skin, specifically in keratinocytes, and that it is under negative transcriptional control of p21(Cip1/WAF1), independently from the cell cycle. Although GITR expression is higher in p21-deficient keratinocytes and skin, it is down-modulated with differentiation and in response to UVB. The combined analysis of keratinocytes with increased GITR expression versus normal keratinocytes and skin of mice with a disruption of the GITR gene indicates that this protein protects keratinocytes from UVB-induced apoptosis both in vitro and in vivo.

Silver-base metal epithermal vein and listwaenite types of deposit Crnac, Rogozna Mts., Kosovo. Part I: Ore mineral geochemistry and sulfur isotope study

Pb-Zn-Ag vein and listwaenite types of mineralization in Crnac deposit, Western Vardar zone, were deposited within several stages: (i) the pre-ore stage comprises pyrite, arsenopyrite, pyrrhotite, quartz, kaolinite and is followed by magnetite-pyrite; (ii) the syn-ore stage is composed of galena, sphalerite, tetrahedrite and stefanite; and (iii) the post-ore stage is composed of carbonates, pyrite, arsenopyrite and minor galena. The vein type mineralization is hosted by Jurassic amphibolites and veins terminate within overlying serpentinites. Mineralized listwaenites are developed along the serpentinite-amphibolite interface. The reserves are estimated to 1.7 Mt of ore containing in average 7.6% lead, 2.9% zinc, and 102 g/t silver. Sulfides from the pre- and syn-mineralization assemblage of the vein- and listwaenite-types of mineralization from the Crnac Pb-Zn-Ag deposit have been analyzed using microprobe, crush-leachates and sulfur isotopes. The pre-ore assemblage precipitated under high sulfur fugacities (f(S(2)) = 10(-8)-10(-6) bar) from temperatures ranging between 350 degrees C and 380 degrees C. Most likely water-rock reactions, boiling and/or increase of pH caused an increase of delta(34)S of pyrite toward upper levels within the deposit. The decomposition of pre-ore pyrrhotite to a pyrite-magnetite mixture occurred at a fugacity of sulfur from f(S(2)) = 8.7 x 10(-10) to 9.6 x 10(-9) bar and fugacity of oxygen from f(O(2)) = 2.4 x 10(-30) to 3.1 x 10(-28) bars, indicating a contribution of an oxidizing fluid, i.e. meteoric water during pre-ore stages of hydrothermal activity. The crystallization temperatures obtained by the sphalerite-galena isotope geothermometer range from 230 to 310 degrees C. The delta(34)S values of pre- and syn-ore sulfides (pyrite, galena, sphalerite, delta(34)S = 0.3-5.9 parts per thousand) point to magmatic sulfur. Values of delta(34)S of galena and sphalerite are decreasing upwards due to precipitation of early formed sulfide minerals. Post-ore assemblage precipitated at temperature below 190 degrees C. Based on data presented above, we assume two fluid sources: (i) a magmatic source, supported by sulfur isotopic compositions within pre- and syn-ore minerals and a high mol% of fluorine found within pre- and syn-ore leachates, and (ii) a meteoric source, deduced by coincident pyrite-magnetite intergrowth, sulfur isotopic trends within syn-ore minerals and decrease of crystallization temperatures from the pre-ore stage (380-350 degrees C), towards the syn-ore (310-215 degrees C) and post-ore stages (<190 degrees C). Post-ore fluids are Na-Ca-Mg-K-Li chlorine rich and were modified via water-rock reactions. Simple mineral assemblage and sphalerite composition range from 1.5 to 10.1 mol% of FeS catalog Crnac to a group of intermediate sulfidation epithermal deposit. (C) 2011 Elsevier B.V. All rights reserved.

Insulin resistance in mice lacking neuronal nitric oxide synthase is related to an alpha-adrenergic mechanism

Rapport de synthèse : Le monoxyde d'azote (NO) joue un rôle important dans la régulation de l'homéostasie du système cardiovasculaire et du glucose. Les souris déficientes pour le gène codant l'isoforme neuronale de la synthase de monoxyde d'azote (nNOS) sont résistantes à l'insuline, mais les mécanismes sous-jacents sont inconnus. Le manque de NO produit par la nNOS pourrait être à l'origine d'une diminution de la perfusion du muscle squelettique et ainsi d'une diminution de l'apport de substrat. Alternativement, le déficit de nNOS normalement hautement exprimé dans le tissu musculaire squelettique pourrait directement y perturber la consommation de glucose. Finalement l'absence de l'action sympatholytique du NO neuronal pourrait diminuer la sensibilité à l'insuline. Afin de tester ces hypothèses nous avons étudié, chez des souris déficientes en nNOS et des souris-contrôle, la consommation corporelle totale de glucose et le flux musculaire squelettique pendant des clamps hyperinsulinémiques euglycémiques in vivo, ainsi que la consommation de glucose dans le muscle squelettique in vitro. De plus nous avons analysé les effets d'une inhibition alpha-adrénergique sur la consommation de glucose pendant les clamps hyperinsulinémiques euglycémiques in vivo. Le taux de perfusion de glucose pendant les clamps était grossièrement 15 pourcent plus bas (P<0.001) chez les souris déficientes en nNOS que chez les souris-contrôle. Cette résistance à l'insuline chez les souris déficientes en nNOS n'était due ni à une stimulation déficiente du flux sanguin musculaire par l'insuline ni à un défaut intrinsèque de la consommation de glucose du muscle (qui étaient comparables dans les deux groupes), mais à un mécanisme alpha-adrénergique, car l'administration de phentolamine rétablissait la sensibilité à l'insuline chez les souris déficientes en nNOS. Ces résultats suggèrent qu'une hyperactivité sympathique, potentiellement due à la perte de l'inhibition neuronale centrale du flux sympathique par le NO provenant de nNOS, contribue à la résistance à l'insuline des souris déficientes en nNOS. Par ailleurs ces résultats tendent à prouver qu'un défaut de production de NO provoquerait une résistance à l'insuline par des mécanismes différents selon l'isoforme de NO synthase déficiente (par exemple chez les souris déficientes pour la forme endothéliale de NO synthase, il a été montré que la résistance à l'insuline est due à un défaut de stimulation de la perfusion musculaire par l'insuline et à un défaut du signalling de l'insuline dans la cellule musculaire squelettique). Chez l'être humain il est établi que les états de résistance à l'insuline sont associés à une synthèse défectueuse et/ou une mauvaise biodisponibilité du NO, ainsi qu'à une hyperactivité sympathique. Nous spéculons que la perte d'inhibition centrale du flux sympathique représente un mécanisme contribuant à la résistance à l'insuline et ses complications cardiovasculaires chez l'être humain.

Sulfur isotope variations from orebody to hand-specimen scale at the Mezica lead-zinc deposit, Slovenia: a predominantly biogenic pattern

The Mississippi Valley-type (MVT) Pb-Zn ore district at Mezica is hosted by Middle to Upper Triassic platform carbonate rocks in the Northern Karavanke/Drau Range geotectonic units of the Eastern Alps, northeastern Slovenia. The mineralization at Mezica covers an area of 64 km(2) with more than 350 orebodies and numerous galena and sphalerite occurrences, which formed epigenetically, both conformable and discordant to bedding. While knowledge on the style of mineralization has grown considerably, the origin of discordant mineralization is still debated. Sulfur stable isotope analyses of 149 sulfide samples from the different types of orebodies provide new insights on the genesis of these mineralizations and their relationship. Over the whole mining district, sphalerite and galena have delta(34)S values in the range of -24.7 to -1.5% VCDT (-13.5 +/- 5.0%) and -24.7 to -1.4% (-10.7 +/- 5.9%), respectively. These values are in the range of the main MVT deposits of the Drau Range. All sulfide delta(34)S values are negative within a broad range, with delta(34)S(pyrite) < delta(34)S(sphalerite) < delta(34)S(galena) for both conformable and discordant orebodies, indicating isotopically heterogeneous H(2)S in the ore-forming fluids and precipitation of the sulfides at thermodynamic disequilibrium. This clearly supports that the main sulfide sulfur originates from bacterially mediated reduction (BSR) of Middle to Upper Triassic seawater sulfate or evaporite sulfate. Thermochemical sulfate reduction (TSR) by organic compounds contributed a minor amount of (34)S-enriched H(2)S to the ore fluid. The variations of delta(34)S values of galena and coarse-grained sphalerite at orefield scale are generally larger than the differences observed in single hand specimens. The progressively more negative delta(34)S values with time along the different sphalerite generations are consistent with mixing of different H(2)S sources, with a decreasing contribution of H(2)S from regional TSR, and an increase from a local H(2)S reservoir produced by BSR (i.e., sedimentary biogenic pyrite, organo-sulfur compounds). Galena in discordant ore (-11.9 to -1.7%; -7.0 +/- 2.7%, n=12) tends to be depleted in (34)S compared with conformable ore (-24.7 to -2.8%, -11.7 +/- 6.2%, n=39). A similar trend is observed from fine-crystalline sphalerite I to coarse open-space filling sphalerite II. Some variation of the sulfide delta(34)S values is attributed to the inherent variability of bacterial sulfate reduction, including metabolic recycling in a locally partially closed system and contribution of H(2)S from hydrolysis of biogenic pyrite and thermal cracking of organo-sulfur compounds. The results suggest that the conformable orebodies originated by mixing of hydrothermal saline metal-rich fluid with H(2)S-rich pore waters during late burial diagenesis, while the discordant orebodies formed by mobilization of the earlier conformable mineralization.

The peroxisome proliferator-activated receptor (PPAR) β/δ agonist GW501516 inhibits IL-6-induced signal transducer and activator of transcription 3 (STAT3) activation and insulin resistance in human liver cells.

AIM/HYPOTHESIS: IL-6 induces insulin resistance by activating signal transducer and activator of transcription 3 (STAT3) and upregulating the transcription of its target gene SOCS3. Here we examined whether the peroxisome proliferator-activated receptor (PPAR)β/δ agonist GW501516 prevented activation of the IL-6-STAT3-suppressor of cytokine signalling 3 (SOCS3) pathway and insulin resistance in human hepatic HepG2 cells. METHODS: Studies were conducted with human HepG2 cells and livers from mice null for Pparβ/δ (also known as Ppard) and wild-type mice. RESULTS: GW501516 prevented IL-6-dependent reduction in insulin-stimulated v-akt murine thymoma viral oncogene homologue 1 (AKT) phosphorylation and in IRS-1 and IRS-2 protein levels. In addition, treatment with this drug abolished IL-6-induced STAT3 phosphorylation of Tyr⁷⁰⁵ and Ser⁷²⁷ and prevented the increase in SOCS3 caused by this cytokine. Moreover, GW501516 prevented IL-6-dependent induction of extracellular-related kinase 1/2 (ERK1/2), a serine-threonine protein kinase involved in serine STAT3 phosphorylation; the livers of Pparβ/δ-null mice showed increased Tyr⁷⁰⁵- and Ser⁷²⁷-STAT3 as well as phospho-ERK1/2 levels. Furthermore, drug treatment prevented the IL-6-dependent reduction in phosphorylated AMP-activated protein kinase (AMPK), a kinase reported to inhibit STAT3 phosphorylation on Tyr⁷⁰⁵. In agreement with the recovery in phospho-AMPK levels observed following GW501516 treatment, this drug increased the AMP/ATP ratio and decreased the ATP/ADP ratio. CONCLUSIONS/INTERPRETATION: Overall, our findings show that the PPARβ/δ activator GW501516 prevents IL-6-induced STAT3 activation by inhibiting ERK1/2 phosphorylation and preventing the reduction in phospho-AMPK levels. These effects of GW501516 may contribute to the prevention of cytokine-induced insulin resistance in hepatic cells.

Effect of intradialytic resistance band exercise on physical function in patients on maintenance hemodialysis: a pilot study.

Although physical activity is recommended in patients on maintenance hemodialysis (MHD), randomized controlled trials testing the effects of exercise in this population have given conflicting results. In general, aerobic exercises mostly failed to produce improvements in physical function, whereas resistance exercises, although less studied, appeared to be more promising. The use of sophisticated materials such as leg press and free weights may preclude widespread application of resistance training in patients on MHD. Simple and cheap elastic bands may thus be an attractive alternative. We tested the feasibility of a supervised intradialytic resistance band exercise training program, and its effects on physical function, in patients on MHD. A total of 11 unselected adult patients on MHD from our center, aged 70 ± 10.7 (mean ± standard deviation) years, including 8 men and 3 women, accepted to follow the program under the supervision of qualified physiotherapists. Thirty-six exercise sessions of moderate intensity (twice a week, mean duration 40 minutes each, during 4.5 to 6 months), mainly involving leg muscles against an elastic resistance, were performed. The exercise program was well tolerated and all patients completed it. Statistically significant improvements were observed in the following tests: Tinetti test, 23.9 ± 3.9 points before versus 25.7 ± 3.5 points after the program (P = .022); the Timed Up and Go test, 12.1 ± 6.6 versus 10 ± 5.8 seconds (P = .0156). Improvements in the 6-minute walk distance and in the one-leg balance tests just failed to reach statistical significance. In this single-center pilot study, an intradialytic resistance band exercise program was feasible, well tolerated, and showed encouraging results on physical function.

Calcineurin as a Multifunctional Regulator: Unraveling Novel Functions in Fungal Stress Responses, Hyphal Growth, Drug Resistance, and Pathogenesis.

Calcineurin signaling plays diverse roles in fungi in regulating stress responses, morphogenesis and pathogenesis. Although calcineurin signaling is conserved among fungi, recent studies indicate important divergences in calcineurin-dependent cellular functions among different human fungal pathogens. Fungal pathogens utilize the calcineurin pathway to effectively survive the host environment and cause life-threatening infections. The immunosuppressive calcineurin inhibitors (FK506 and cyclosporine A) are active against fungi, making targeting calcineurin a promising antifungal drug development strategy. Here we summarize current knowledge on calcineurin in yeasts and filamentous fungi, and review the importance of understanding fungal-specific attributes of calcineurin to decipher fungal pathogenesis and develop novel antifungal therapeutic approaches.

PI3Kγ within a nonhematopoietic cell type negatively regulates diet-induced thermogenesis and promotes obesity and insulin resistance.

Obesity is associated with a chronic low-grade inflammation, and specific antiinflammatory interventions may be beneficial for the treatment of type 2 diabetes and other obesity-related diseases. The lipid kinase PI3Kγ is a central proinflammatory signal transducer that plays a major role in leukocyte chemotaxis, mast cell degranulation, and endothelial cell activation. It was also reported that PI3Kγ activity within hematopoietic cells plays an important role in obesity-induced inflammation and insulin resistance. Here, we show that protection from insulin resistance, metabolic inflammation, and fatty liver in mice lacking functional PI3Kγ is largely consequent to their leaner phenotype. We also show that this phenotype is largely based on decreased fat gain, despite normal caloric intake, consequent to increased energy expenditure. Furthermore, our data show that PI3Kγ action on diet-induced obesity depends on PI3Kγ activity within a nonhematopoietic compartment, where it promotes energetic efficiency for fat mass gain. We also show that metabolic modulation by PI3Kγ depends on its lipid kinase activity and might involve kinase-independent signaling. Thus, PI3Kγ is an unexpected but promising drug target for the treatment of obesity and its complications.

Surveillance of HIV type 1 drug resistance among naive patients from Venezuela.

We have studied 65 HIV-1-infected untreated patients recruited in Caracas, Venezuela with TCD4 counts > or =350/microl. The reverse transcriptase and protease sequences of the virus were sequenced, aligned with reference HIV-1 group M strains, and analyzed for drug resistance mutations. Most of the viruses were subtype B genotype in both the protease and RT genomic regions. Five of the 62 virus isolates successfully amplified showed evidence of recombination between protease and RT, with their protease region being non-B while their RT region was derived from subtype B. Four strains were found bearing resistance mutations either to NRTIs, NNRTIs, or PIs. The prevalence of HIV-1 isolates bearing resistance mutations was therefore above the 5% threshold of WHO.

Predictors for the emergence of the 2 multi-nucleoside/nucleotide resistance mutations 69 insertion and Q151M and their impact on clinical outcome in the Swiss HIV cohort study.

The 69 insertion and Q151M mutations are multi-nucleoside/nucleotide resistance mutations (MNR). The prevalence among 4078 antiretroviral therapy (ART)-experienced individuals was <1.3%. Combined ART fully prevented MNR in subtype B infections. Case-control studies were performed to identify risk factors. Control subjects were patients with ≥ 3 thymidine-analogue mutations. The 69 insertion study (27 control subjects, 14 case patients) identified didanosine exposure as a risk (odds ratio, 5.0 per year; P = .019), whereas the Q151M study (which included 44 control subjects and 25 case patients) detected no associations. Following detection, individuals with Q151M tended to have lower suppression rates and higher mortality rates, relative to control subjects. Additional studies are needed to verify these findings in non-subtype B infections.

Development of a cross-European virtual sample repository and HIV resistance database

BACKGROUND: Several European HIV observational data bases have, over the last decade, accumulated a substantial number of resistance test results and developed large sample repositories, There is a need to link these efforts together, We here describe the development of such a novel tool that allows to bind these data bases together in a distributed fashion for which the control and data remains with the cohorts rather than classic data mergers.METHODS: As proof-of-concept we entered two basic queries into the tool: available resistance tests and available samples. We asked for patients still alive after 1998-01-01, and between 180 and 195 cm of height, and how many samples or resistance tests there would be available for these patients, The queries were uploaded with the tool to a central web server from which each participating cohort downloaded the queries with the tool and ran them against their database, The numbers gathered were then submitted back to the server and we could accumulate the number of available samples and resistance tests.RESULTS: We obtained the following results from the cohorts on available samples/resistance test: EuResist: not availableI11,194; EuroSIDA: 20,71611,992; ICONA: 3,751/500; Rega: 302/302; SHCS: 53,78311,485, In total, 78,552 samples and 15,473 resistance tests were available amongst these five cohorts. Once these data items have been identified, it is trivial to generate lists of relevant samples that would be usefuI for ultra deep sequencing in addition to the already available resistance tests, Saon the tool will include small analysis packages that allow each cohort to pull a report on their cohort profile and also survey emerging resistance trends in their own cohort,CONCLUSIONS: We plan on providing this tool to all cohorts within the Collaborative HIV and Anti-HIV Drug Resistance Network (CHAIN) and will provide the tool free of charge to others for any non-commercial use, The potential of this tool is to ease collaborations, that is, in projects requiring data to speed up identification of novel resistance mutations by increasing the number of observations across multiple cohorts instead of awaiting single cohorts or studies to reach the critical number needed to address such issues.

Eumelanin- and pheomelanin-based colour advertise resistance to oxidative stress in opposite ways.

The control mechanisms and information content of melanin-based colourations are still debated among evolutionary biologists. Recent hypotheses contend that molecules involved in melanogenesis alter other physiological processes, thereby generating covariation between melanin-based colouration and other phenotypic attributes. Interestingly, several molecules such as agouti and glutathione that trigger the production of reddish-brown pheomelanin have an inhibitory effect on the production of black/grey eumelanin, whereas other hormones, such as melanocortins, have the opposite effect. We therefore propose the hypothesis that phenotypic traits positively correlated with the degree of eumelanin-based colouration may be negatively correlated with the degree of pheomelanin-based colouration, or vice versa. Given the role played by the melanocortin system and glutathione on melanogenesis and resistance to oxidative stress, we examined the prediction that resistance to oxidative stress is positively correlated with the degree of black colouration but negatively with the degree of reddish colouration. Using the barn owl (Tyto alba) as a model organism, we swapped eggs between randomly chosen nests to allocate genotypes randomly among environments and then we measured resistance to oxidative stress using the KRL assay in nestlings raised by foster parents. As predicted, the degree of black and reddish pigmentations was positively and negatively correlated, respectively, with resistance to oxidative stress. Our results reveal that eumelanin- and pheomelanin-based colourations can be redundant signals of resistance to oxidative stress.

A stroma-related gene signature predicts resistance to neoadjuvant chemotherapy in breast cancer.

To better understand the relationship between tumor-host interactions and the efficacy of chemotherapy, we have developed an analytical approach to quantify several biological processes observed in gene expression data sets. We tested the approach on tumor biopsies from individuals with estrogen receptor-negative breast cancer treated with chemotherapy. We report that increased stromal gene expression predicts resistance to preoperative chemotherapy with 5-fluorouracil, epirubicin and cyclophosphamide (FEC) in subjects in the EORTC 10994/BIG 00-01 trial. The predictive value of the stromal signature was successfully validated in two independent cohorts of subjects who received chemotherapy but not in an untreated control group, indicating that the signature is predictive rather than prognostic. The genes in the signature are expressed in reactive stroma, according to reanalysis of data from microdissected breast tumor samples. These findings identify a previously undescribed resistance mechanism to FEC treatment and suggest that antistromal agents may offer new ways to overcome resistance to chemotherapy.