88 research outputs found

    Disruption of Toxoplasma gondii Parasitophorous Vacuoles by the Mouse p47-Resistance GTPases

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    The p47 GTPases are essential for interferon-γ-induced cell-autonomous immunity against the protozoan parasite, Toxoplasma gondii, in mice, but the mechanism of resistance is poorly understood. We show that the p47 GTPases, including IIGP1, accumulate at vacuoles containing T. gondii. The accumulation is GTP-dependent and requires live parasites. Vacuolar IIGP1 accumulations undergo a maturation-like process accompanied by vesiculation of the parasitophorous vacuole membrane. This culminates in disruption of the parasitophorous vacuole and finally of the parasite itself. Over-expression of IIGP1 leads to accelerated vacuolar disruption whereas a dominant negative form of IIGP1 interferes with interferon-γ-mediated killing of intracellular parasites. Targeted deletion of the IIGP1 gene results in partial loss of the IFN-γ-mediated T. gondii growth restriction in mouse astrocytes

    Ferromagnetic behavior of ultrathin manganese nanosheets

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    Ferromagnetic behaviour has been observed experimentally for the first time in nanostructured Manganese. Ultrathin (\sim 0.6 nm) Manganese nanosheets have been synthesized inside the two dimensional channels of sol-gel derived Na-4 mica. The magnetic properties of the confined system are measured within 2K-300K temperature range. The confined structure is found to show a ferromagnetic behaviour with a nonzero coercivity value. The coercivity value remains positive throughout the entire temperature range of measurement. The experimental variation of susceptibility as a function of temperature has been satisfactorily explained on the basis of a two dimensional system with a Heisenberg Hamiltonian involving direct exchange interaction.Comment: 13 pages, 9 figure

    A Dedicated Promoter Drives Constitutive Expression of the Cell-Autonomous Immune Resistance GTPase, Irga6 (IIGP1) in Mouse Liver

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    Background: In general, immune effector molecules are induced by infection. Methodology and Principal Findings: However, strong constitutive expression of the cell-autonomous resistance GTPase, Irga6 (IIGP1), was found in mouse liver, contrasting with previous evidence that expression of this protein is exclusively dependent on induction by IFNc. Constitutive and IFNc-inducible expression of Irga6 in the liver were shown to be dependent on transcription initiated from two independent untranslated 59 exons, which splice alternatively into the long exon encoding the full-length protein sequence. Irga6 is expressed constitutively in freshly isolated hepatocytes and is competent in these cells to accumulate on the parasitophorous vacuole membrane of infecting Toxoplasma gondii tachyzoites. Conclusions and Significance: The role of constitutive hepatocyte expression of Irga6 in resistance to parasites invading from the gut via the hepatic portal system is discussed

    Blood pressure and metabolic effects of acetyl-L-carnitine in type 2 diabetes: DIABASI randomized controlled trial

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    Context: Acetyl-L-carnitine (ALC), a mitochondrial carrier involved in lipid oxidation and glucose metabolism, decreased systolic blood pressure (SBP), and ameliorated insulin sensitivity in hypertensive nondiabetic subjects at high cardiovascular risk. Objective: To assess the effects of ALC on SBP and glycemic and lipid control in patients with hypertension, type 2 diabetes mellitus (T2D), and dyslipidemia on background statin therapy. Design: After 4-week run-in period and stratification according to previous statin therapy, patients were randomized to 6-month, double-blind treatment with ALC or placebo added-on simvastatin. Setting: Five diabetology units and one clinical research center in Italy. Patients: Two hundred twenty-nine patients with hypertension and dyslipidemic T2D > 40 years with stable background antihypertensive, hypoglycemic, and statin therapy and serum creatinine < 1.5 mg/ dL. Interventions: Oral ALC 1000 mg or placebo twice daily on top of stable simvastatin therapy. Outcome and Measures: Primary outcome was SBP. Secondary outcomes included lipid and glycemic profiles. Total-body glucose disposal rate and glomerular filtration rate were measured in subgroups by hyperinsulinemic-euglycemic clamp and iohexol plasma clearance, respectively. Results: SBP did not significantly change after 6-month treatment with ALC compared with placebo (-2.09mmHg vs-3.57mmHg, P = 0.9539). Serum cholesterol, triglycerides, and lipoprotein(a), as well as blood glucose, glycated hemoglobin, fasting insulin levels, homeostatic model assessment of insulin resistance index, glucose disposal rate, and glomerular filtration rate did not significantly differ between treatments. Adverse events were comparable between groups. Conclusions: Six-month oral ALC supplementation did not affect blood pressure, lipid and glycemic control, insulin sensitivity and kidney function in hypertensive normoalbuminuric and microalbuminuric T2D patients on background statin therapy

    Association Between Insulin Resistance and Development of Microalbuminuria in Type 2 Diabetes: A prospective cohort study

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    [[abstract]]OBJECTIVE An association between insulin resistance and microalbuminuria in type 2 diabetes has often been found in cross-sectional studies. We aimed to reassess this relationship in a prospective Taiwanese cohort of type 2 diabetic subjects. RESEARCH DESIGN AND METHODS We enrolled 738 normoalbuminuric type 2 diabetic subjects, aged 56.6 +/- 9.0 years, between 2003 and 2005 and followed them through the end of 2009. Average follow-up time was 5.2 +/- 0.8 years. We used urine albumin-to-creatinine ratio to define microalbuminuria and the homeostasis model assessment for insulin resistance (HOMA-IR) to assess insulin resistance. The incidence rate ratio and Cox proportional hazard model were used to evaluate the association between HOMA-IR and development of microalbuminuria. RESULTS We found incidences of microalbuminuria of 64.8, 83.5, 93.3, and 99.0 per 1,000 person-years for the lowest to highest quartiles of HOMA-IR. Compared with those in the lowest quartile of HOMA-IR, the incidence rate ratio for those in the 2nd, 3rd, and highest quartiles were 1.28 (95% CI 0.88-1.87), 1.44 (0.99-2.08), and 1.52 (1.06-2.20), respectively (trend test: P < 0.001). By comparison with those in the lowest quartile, the adjusted hazard ratios were 1.37 (0.93-2.02), 1.66 (1.12-2.47), and 1.76 (1.20-2.59) for those in the 2nd, 3rd, and highest HOMA-IR quartiles, respectively. CONCLUSIONS According to the dose-response effects of HOMA-IR shown in this prospective study, we conclude that insulin resistance could significantly predict development of microalbuminuria in type 2 diabetic patients

    Early detection of diabetic kidney disease by urinary proteomics and subsequent intervention with spironolactone to delay progression (PRIORITY): a prospective observational study and embedded randomised placebo-controlled trial

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    Background: Microalbuminuria is an early sign of kidney disease in people with diabetes and indicates increased risk of cardiovascular disease. We tested whether a urinary proteomic risk classifier (CKD273) score was associated with development of microalbuminuria and whether progression to microalbuminuria could be prevented with the mineralocorticoid receptor antagonist spironolactone. Methods: In this multicentre, prospective, observational study with embedded randomised controlled trial (PRIORITY), we recruited people with type 2 diabetes, normal urinary albumin excretion, and preserved renal function from 15 specialist centres in ten European countries. All participants (observational cohort) were tested with the CKD273 classifier and classified as high risk (CKD273 classifier score &gt;0·154) or low risk (≤0·154). Participants who were classified as high risk were entered into a randomised controlled trial and randomly assigned (1:1), by use of an interactive web-response system, to receive spironolactone 25 mg once daily or matched placebo (trial cohort). The primary endpoint was development of confirmed microalbuminuria in all individuals with available data (observational cohort). Secondary endpoints included reduction in incidence of microalbuminuria with spironolactone (trial cohort, intention-to-treat population) and association between CKD273 risk score and measures of impaired renal function based on estimated glomerular filtration rate (eGFR; observational cohort). Adverse events (particularly gynaecomastia and hyperkalaemia) and serious adverse events were recorded for the intention-to-treat population (trial cohort). This study is registered with the EU Clinical Trials Register (EudraCT 20120-004523-4) and ClinicalTrials.gov (NCT02040441) and is completed. Findings: Between March 25, 2014, and Sept 30, 2018, we enrolled and followed-up 1775 participants (observational cohort), 1559 (88%) of 1775 participants had a low-risk urinary proteomic pattern and 216 (12%) had a high-risk pattern, of whom 209 were included in the trial cohort and assigned to spironolactone (n=102) or placebo (n=107). The overall median follow-up time was 2·51 years (IQR 2·0–3·0). Progression to microalbuminuria was seen in 61 (28%) of 216 high-risk participants and 139 (9%) of 1559 low-risk participants (hazard ratio [HR] 2·48, 95% CI 1·80–3·42; p&lt;0·0001, after adjustment for baseline variables of age, sex, HbA1c, systolic blood pressure, retinopathy, urine albumin-to-creatinine ratio [UACR], and eGFR). Development of impaired renal function (eGFR &lt;60 mL/min per 1·73 m2) was seen in 48 (26%) of 184 high-risk participants and 119 (8%) of 1423 low-risk participants (HR 3·50; 95% CI 2·50–4·90, after adjustment for baseline variables). A 30% decrease in eGFR from baseline (post-hoc endpoint) was seen in 42 (19%) of 216 high-risk participants and 62 (4%) of 1559 low-risk participants (HR 5·15, 95% CI 3·41–7·76; p&lt;0·0001, after adjustment for basline eGFR and UACR). In the intention-to-treat trial cohort, development of microalbuminuria was seen in 35 (33%) of 107 in the placebo group and 26 (25%) of 102 in the spironolactone group (HR 0·81, 95% CI 0·49–1·34; p=0·41). In the safety analysis (intention-to-treat trial cohort), events of plasma potassium concentrations of more than 5·5 mmol/L were seen in 13 (13%) of 102 participants in the spironolactone group and four (4%) of 107 participants in the placebo group, and gynaecomastia was seen in three (3%) participants in the spironolactone group and none in the placebo group. One patient died in the placebo group due to a cardiac event (considered possibly related to study drug) and one patient died in the spironolactone group due to cancer, deemed unrelated to study drug. Interpretation: In people with type 2 diabetes and normoalbuminuria, a high-risk score from the urinary proteomic classifier CKD273 was associated with an increased risk of progression to microalbuminuria over a median of 2·5 years, independent of clinical characteristics. However, spironolactone did not prevent progression to microalbuminuria in high-risk patients. Funding: European Union Seventh Framework Programme

    A Small Molecule Inhibitor of Signal Peptide Peptidase Inhibits Plasmodium Development in the Liver and Decreases Malaria Severity

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    The liver stage of Plasmodium's life cycle is the first, obligatory step in malaria infection. Decreasing the hepatic burden of Plasmodium infection decreases the severity of disease and constitutes a promising strategy for malaria prophylaxis. The efficacy of the gamma-secretase and signal peptide peptidase inhibitor LY411,575 in targeting Plasmodium liver stages was evaluated both in human hepatoma cell lines and in mouse primary hepatocytes. LY411,575 was found to prevent Plasmodium's normal development in the liver, with an IC50 of approximately 80 nM, without affecting hepatocyte invasion by the parasite. In vivo results with a rodent model of malaria showed that LY411,575 decreases the parasite load in the liver and increases by 55% the resistance of mice to cerebral malaria, one of the most severe malaria-associated syndromes. Our data show that LY411,575 does not exert its effect via the Notch signaling pathway suggesting that it may interfere with Plasmodium development through an inhibition of the parasite's signal peptide peptidase. We therefore propose that selective signal peptide peptidase inhibitors could be potentially used for preventive treatment of malaria in humans

    Determinants of urinary albumin excretion within the normal range in patients with type 2 diabetes: the Randomised Olmesartan and Diabetes Microalbuminuria Prevention (ROADMAP) study

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    In contrast to microalbuminuric type 2 diabetic patients, the factors correlated with urinary albumin excretion are less well known in normoalbuminuric patients. This may be important because even within the normoalbuminuric range, higher rates of albuminuria are known to be associated with higher renal and cardiovascular risk. At the time of screening for the Randomised Olmesartan and Diabetes Microalbuminuria Prevention (ROADMAP) Study, the urinary albumin/creatinine ratio (UACR) was 0.44 mg/mmol in 4,449 type 2 diabetic patients. The independent correlates of UACR were analysed. Independent correlates of UACR during baseline were (in descending order): night-time systolic BP (r (s) = 0.19); HbA(1c) (r (s) = 0.18); mean 24 h systolic BP (r (s) = 0.16); fasting blood glucose (r (s) = 0.16); night-time diastolic BP (r (s) = 0.12); office systolic BP, sitting (r (s) = 0.11), standing (r (s) = 0.10); estimated GFR (r (s) = 0.10); heart rate, sitting (r (s) = 0.10); haemoglobin (r (s) = -0.10); triacylglycerol (r (s) = 0.09); and uric acid (r (s) = -0.08; all p a parts per thousand currency signaEuro parts per thousand 0.001). Significantly higher albumin excretion rates were found for the following categorical variables: higher waist circumference (more marked in men); presence of the metabolic syndrome; smoking (difference more marked in males); female sex; antihypertensive treatment; use of amlodipine; insulin treatment; family history of diabetes; and family history of cardiovascular disease (more marked in women). Although observational correlations do not prove causality, in normoalbuminuric type 2 diabetic patients the albumin excretion rate is correlated with many factors that are potentially susceptible to intervention. ClinicalTrials.gov ID no.: NCT00185159 This study was sponsored by Daichii-Sankyo.Nephrolog

    Transcriptional Activation of OsDERF1 in OsERF3 and OsAP2-39 Negatively Modulates Ethylene Synthesis and Drought Tolerance in Rice

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    The phytohormone ethylene is a key signaling molecule that regulates a variety of developmental processes and stress responses in plants. Transcriptional modulation is a pivotal process controlling ethylene synthesis, which further triggers the expression of stress-related genes and plant adaptation to stresses; however, it is unclear how this process is transcriptionally modulated in rice. In the present research, we report the transcriptional regulation of a novel rice ethylene response factor (ERF) in ethylene synthesis and drought tolerance. Through analysis of transcriptional data, one of the drought-responsive ERF genes, OsDERF1, was identified for its activation in response to drought, ethylene and abscisic acid. Transgenic plants overexpressing OsDERF1 (OE) led to reduced tolerance to drought stress in rice at seedling stage, while knockdown of OsDERF1 (RI) expression conferred enhanced tolerance at seedling and tillering stages. This regulation was supported by negative modulation in osmotic adjustment response. To elucidate the molecular basis of drought tolerance, we identified the target genes of OsDERF1 using the Affymetrix GeneChip, including the activation of cluster stress-related negative regulators such as ERF repressors. Biochemical and molecular approaches showed that OsDERF1 at least directly interacted with the GCC box in the promoters of ERF repressors OsERF3 and OsAP2-39. Further investigations showed that OE seedlings had reduced expression (while RI lines showed enhanced expression) of ethylene synthesis genes, thereby resulting in changes in ethylene production. Moreover, overexpression of OsERF3/OsAP2-39 suppressed ethylene synthesis. In addition, application of ACC recovered the drought-sensitive phenotype in the lines overexpressing OsERF3, showing that ethylene production contributed to drought response in rice. Thus our data reveal that a novel ERF transcriptional cascade modulates drought response through controlling the ethylene synthesis, deepening our understanding of the regulation of ERF proteins in ethylene related drought response
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