Redox signals at the ER-mitochondria interface control melanoma progression.

Reactive oxygen species (ROS) are emerging as important regulators of cancer growth and metastatic spread. However, how cells integrate redox signals to affect cancer progression is not fully understood. Mitochondria are cellular redox hubs, which are highly regulated by interactions with neighboring organelles. Here, we investigated how ROS at the endoplasmic reticulum (ER)-mitochondria interface are generated and translated to affect melanoma outcome. We show that TMX1 and TMX3 oxidoreductases, which promote ER-mitochondria communication, are upregulated in melanoma cells and patient samples. TMX knockdown altered mitochondrial organization, enhanced bioenergetics, and elevated mitochondrial- and NOX4-derived ROS. The TMX-knockdown-induced oxidative stress suppressed melanoma proliferation, migration, and xenograft tumor growth by inhibiting NFAT1. Furthermore, we identified NFAT1-positive and NFAT1-negative melanoma subgroups, wherein NFAT1 expression correlates with melanoma stage and metastatic potential. Integrative bioinformatics revealed that genes coding for mitochondrial- and redox-related proteins are under NFAT1 control and indicated that TMX1, TMX3, and NFAT1 are associated with poor disease outcome. Our study unravels a novel redox-controlled ER-mitochondria-NFAT1 signaling loop that regulates melanoma pathobiology and provides biomarkers indicative of aggressive disease

Overexpression of branched-chain amino acid aminotransferases rescues the growth defects of cells lacking the Barth syndrome-related gene TAZ1.

The yeast protein Taz1 is the orthologue of human Tafazzin, a phospholipid acyltransferase involved in cardiolipin (CL) remodeling via a monolyso CL (MLCL) intermediate. Mutations in Tafazzin lead to Barth syndrome (BTHS), a metabolic and neuromuscular disorder that primarily affects the heart, muscles, and immune system. Similar to observations in fibroblasts and platelets from patients with BTHS or from animal models, abolishing yeast Taz1 results in decreased total CL amounts, increased levels of MLCL, and mitochondrial dysfunction. However, the biochemical mechanisms underlying the mitochondrial dysfunction in BTHS remain unclear. To better understand the pathomechanism of BTHS, we searched for multi-copy suppressors of the taz1Δ growth defect in yeast cells. We identified the branched-chain amino acid transaminases (BCATs) Bat1 and Bat2 as such suppressors. Similarly, overexpression of the mitochondrial isoform BCAT2 in mammalian cells lacking TAZ improves their growth. Elevated levels of Bat1 or Bat2 did not restore the reduced membrane potential, altered stability of respiratory complexes, or the defective accumulation of MLCL species in yeast taz1Δ cells. Importantly, supplying yeast or mammalian cells lacking TAZ1 with certain amino acids restored their growth behavior. Hence, our findings suggest that the metabolism of amino acids has an important and disease-relevant role in cells lacking Taz1 function. KEY MESSAGES: Bat1 and Bat2 are multi-copy suppressors of retarded growth of taz1Δ yeast cells. Overexpression of Bat1/2 in taz1Δ cells does not rescue known mitochondrial defects. Supplementation of amino acids enhances growth of cells lacking Taz1 or Tafazzin. Altered metabolism of amino acids might be involved in the pathomechanism of BTSH

Cooperation between COA6 and SCO2 in COX2 maturation during cytochrome c oxidase assembly links two mitochondrial cardiomyopathies.

Three mitochondria-encoded subunits form the catalytic core of cytochrome c oxidase, the terminal enzyme of the respiratory chain. COX1 and COX2 contain heme and copper redox centers, which are integrated during assembly of the enzyme. Defects in this process lead to an enzyme deficiency and manifest as mitochondrial disorders in humans. Here we demonstrate that COA6 is specifically required for COX2 biogenesis. Absence of COA6 leads to fast turnover of newly synthesized COX2 and a concomitant reduction in cytochrome c oxidase levels. COA6 interacts transiently with the copper-containing catalytic domain of newly synthesized COX2. Interestingly, similar to the copper metallochaperone SCO2, loss of COA6 causes cardiomyopathy in humans. We show that COA6 and SCO2 interact and that corresponding pathogenic mutations in each protein affect complex formation. Our analyses define COA6 as a constituent of the mitochondrial copper relay system, linking defects in COX2 metallation to cardiac cytochrome c oxidase deficiency

Kidney volume to GFR ratio predicts functional improvement after revascularization in atheromatous renal artery stenosis

Background: Randomized controlled trials (RCT) have shown no overall benefit of renal revascularization in atherosclerotic renovascular disease (ARVD). However, 25% of patients demonstrate improvement in renal function. We used the ratio of magnetic resonance parenchymal volume (PV) to isotopic single kidney glomerular filtration rate (isoSKGFR) ratio as our method to prospectively identify "improvers" before revascularization. Methods: Patients with renal artery stenosis who were due revascularization were recruited alongside non-ARVD hypertensive CKD controls. Using the controls, 95% CI were calculated for expected PV:isoSK-GFR at given renal volumes. For ARVD patients, “improvers” were defined as having both >15% and >1ml/min increase in isoSK-GFR at 4 months after revascularization. Sensitivity and specificity of PV:isoSK-GFR for predicting improvers was calculated. Results: 30 patients (mean age 68 ±8 years), underwent revascularization, of whom 10 patients had intervention for bilateral RAS. Stented kidneys which manifested >15% improvement in function had larger PV:isoSK-GFR compared to controls (19±16 vs. 6±4ml/ml/min, p = 0.002). The sensitivity and specificity of this equation in predicting a positive renal functional outcome were 64% and 88% respectively. Use of PV:isoSK-GFR increased prediction of functional improvement (area under curve 0.93). Of note, non-RAS contralateral kidneys which improved (n = 5) also demonstrated larger PV:isoSK-GFR (15.2±16.2 ml/ml/min, p = 0.006). Conclusion: This study offers early indicators that the ratio of PV:isoSK-GFR may help identify patients with kidneys suitable for renal revascularization which could improve patient selection for a procedure associated with risks. Calculation of the PV:isoSK-GFR ratio is easy, does not require MRI contrast agent

PHD2 is a regulator for glycolytic reprogramming in macrophages.

The prolyl-4-hydroxylase domain (PHD) enzymes are regarded as the molecular oxygen sensors. There is an interplay between oxygen availability and cellular metabolism, which in turn has significant effects on the functionality of innate immune cells, such as macrophages. However, if and how PHD enzymes affect macrophage metabolism are enigmatic. We hypothesized that macrophage metabolism and function can be controlled via manipulation of PHD2. We characterized the metabolic phenotypes of PHD2-deficient RAW cells and primary PHD2 knockout bone marrow-derived macrophages (BMDM). Both showed typical features of anaerobic glycolysis, which were paralleled by increased pyruvate dehydrogenase kinase 1 (PDK1) protein levels and a decreased pyruvate dehydrogenase enzyme activity. Metabolic alterations were associated with an impaired cellular functionality. Inhibition of PDK1 or knockout of hypoxia-inducible factor 1 alpha (HIF-1 alpha) reversed the metabolic phenotype and impaired the functionality of the PHD2-deficient RAW cells and BMDM. Taking these results together, we identified a critical role of PHD2 for a reversible glycolytic reprogramming in macrophages with a direct impact on their function. We suggest that PHD2 serves as an adjustable switch to control macropha(g)e behavior

Health and wellbeing amongst older people research in Northamptonshire

The Ageing Research Centre of the University of Northampton (2014-current), in collaboration with the East Midlands Research into Ageing Network (EMRAN) is pleased to compile this brochure on research activity associated with older people across the county of Northamptonshire. This provides a comprehensive overview of activity that is relevant and of value to practice, identifying research outcomes that have real significance to age-related health and wellbeing. The brochure provides a summary of research activity over the last five years from academic, clinical and professional colleagues and demonstrates cross sector networks of collaboration around the common agenda of aging. Such collaboration will enhance the capacity of research understanding across the county and provide information and support for the needs of older people, their families and carers. The translation of research outcomes into practice is essential if we are to promote wellness, independence and healthy aging within the county and beyond and I would like to thank all contributors for their commitment and hard work in the production of this brochure

Rounding of low serum creatinine levels and consequent impact on accuracy of bedside estimates of renal function in cancer patients

To compare glomerular filtration rate measured by technetium-99m ([Tc(99m)]) DTPA clearance with estimated creatinine clearance (CrCl) (Cockcroft and Gault (C&G) method) in patients with serum creatinine (Scr) levels 100 ml min(-1). This work indicates that when bedside estimates of renal function are calculated using the C&G formula actual Scr should be used first to estimate CrCl. If the resultant CrCl is </=100 ml min(-1), then the Scr should be rounded up to 0.06 mmol l(-1) and CrCl recalculated. Further assessment of this approach is warranted in a larger cohort of patients

How does study quality affect the results of a diagnostic meta-analysis?

Background: The use of systematic literature review to inform evidence based practice in diagnostics is rapidly expanding. Although the primary diagnostic literature is extensive, studies are often of low methodological quality or poorly reported. There has been no rigorously evaluated, evidence based tool to assess the methodological quality of diagnostic studies. The primary objective of this study was to determine the extent to which variations in the quality of primary studies impact the results of a diagnostic meta-analysis and whether this differs with diagnostic test type. A secondary objective was to contribute to the evaluation of QUADAS, an evidence-based tool for the assessment of quality in diagnostic accuracy studies. Methods: This study was conducted as part of large systematic review of tests used in the diagnosis and further investigation of urinary tract infection (UTI) in children. All studies included in this review were assessed using QUADAS, an evidence-based tool for the assessment of quality in systematic reviews of diagnostic accuracy studies. The impact of individual components of QUADAS on a summary measure of diagnostic accuracy was investigated using regression analysis. The review divided the diagnosis and further investigation of UTI into the following three clinical stages: diagnosis of UTI, localisation of infection, and further investigation of the UTI. Each stage used different types of diagnostic test, which were considered to involve different quality concerns. Results: Many of the studies included in our review were poorly reported. The proportion of QUADAS items fulfilled was similar for studies in different sections of the review. However, as might be expected, the individual items fulfilled differed between the three clinical stages. Regression analysis found that different items showed a strong association with test performance for the different tests evaluated. These differences were observed both within and between the three clinical stages assessed by the review. The results of regression analyses were also affected by whether or not a weighting (by sample size) was applied. Our analysis was severely limited by the completeness of reporting and the differences between the index tests evaluated and the reference standards used to confirm diagnoses in the primary studies. Few tests were evaluated by sufficient studies to allow meaningful use of meta-analytic pooling and investigation of heterogeneity. This meant that further analysis to investigate heterogeneity could only be undertaken using a subset of studies, and that the findings are open to various interpretations. Conclusion: Further work is needed to investigate the influence of methodological quality on the results of diagnostic meta-analyses. Large data sets of well-reported primary studies are needed to address this question. Without significant improvements in the completeness of reporting of primary studies, progress in this area will be limited

A modular tethering complex for endosomal recycling.

How proteins migrate through the interconnected organelles of the endolysosomal system is poorly understood. A piece of the puzzle has been added with the identification of a complex of tethering factors that functions in the recycling of proteins towards the cell surface