Glomerular abundance of complement proteins characterized by proteomic analysis of laser-captured microdissected glomeruli associates with progressive disease in IgA nephropathy

Background

The clinical course of IgA nephropathy (IgAN) is variable and complement activation may predict prognosis. The present study investigated whether glomerular abundance of complement proteins associates with progression to end-stage renal disease (ESRD) in patients for whom prognosis could not be predicted based on clinical variables.

Methods

Based on data from the Norwegian Kidney Biopsy Registry and the Norwegian Renal Registry, three groups were included: IgAN patients with (n = 9) or without (n = 16) progression to ESRD during 10 years, and controls (n = 15) with a normal kidney biopsy. IgAN patients had eGFR > 45 ml/min/1.73 m² and non-nephrotic proteinuria at time of biopsy. Using stored formalin-fixed paraffin embedded kidney biopsy tissue, about 100 glomerular cross sections were microdissected for each patient. Samples were analyzed by liquid chromatography–tandem mass spectrometry and relative abundances of complement proteins were compared between groups.

Results

Proteomic analyses quantified 2018 proteins, of which 28 proteins belong to the complement system. As compared to IgAN patients without progressive disease, glomeruli from patients with progressive IgAN had significantly higher abundance of components of the classical and the terminal complement pathways, and inhibitory factors such as Factor H and factor H related proteins. Abundance of complement proteins classified progressors from non-progressors with an area under ROC curve of 0.91 (p = 0.001). Clinical and morphological data were similar between the two patient groups and could not predict progressive IgAN.

Conclusions

In conclusion, higher glomerular abundance of complement proteins was associated with a progressive clinical course in IgAN and are candidate biomarkers to predict prognosis.

     

A journey on plate tectonics sheds light on European crayfish phylogeography

Crayfish can be used as model organisms in phylogeographic and divergence time studies if reliable calibrations are available. This study presents a comprehensive investigation into the phylogeography of the European stone crayfish (Austropotamobius torrentium) and includes samples from previously unstudied sites. Two mitochondrial markers were used to reveal evolutionary relationships among haplogroups throughout the species’ distributional range and to estimate the divergence time by employing both substitution rates and geological calibration methods. Our haplotype network reconstruction and phylogenetic analyses revealed the existence of a previously unknown haplogroup distributed in Romania's Apuseni Mountains. This haplogroup is closely related to others that are endemic in the Dinarides, despite their vast geographical separation (~600 km). The separation is best explained by the well‐dated tectonic displacement of the Tisza–Dacia microplate, which started in the Miocene (~16 Ma) and possibly carried part of the A. torrentium population to the current location of the Apuseni Mountains. This population may thus have been isolated from the Dinarides for a period of ca. 11 m.y. by marine and lacustrine phases of the Pannonian Basin. The inclusion of this geological event as a calibration point in divergence time analyses challenges currently accepted crayfish evolutionary time frames for the region, constraining the evolution of this area's crayfish to a much earlier date. We discuss why molecular clock calibrations previously employed to date European crayfish species divergences should therefore be reconsidered.     

A retrosynthetic biology approach to therapeutics: from conception to delivery

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Highlights? Retrosynthetic biology has the potential to identify de novo circuits for therapeutics. ? Retrosynthetic biology performs a metabolic backward search to devise and optimize pathways. ? Production, sensing, and delivery circuits are essential parts of next-generation therapeutics.     

Patterns of peripheral cellular immune disorders in severe rheumatoid arthritis

The study is focused on the correlated peripheral cellular immune disorders registered in a group of 23 patients with severe, progressive rheumatoid arthritis, on methotrexate therapy. We investigated a panel of peripheral immune parameters: leukocyte counts, the proportions of lymphocyte populations (T, Thelper, Tcytotoxic/suppressor, B lymphocytes and NK cells) and the polyclonal activation of lymphocytes. Results show that leukocytosis is due to simultaneously elevated values of monocytes, granulocytes and, to a lesser extent, lymphocytes. The registered high values of the Th to Tc/s ratio are mainly attributed to the abnormal low proportions of the Tc/s subpopulation. Inverse correlations were emphasized between B, Tc/s lymphocytes and NK cells or granulocytes. The unbalance of the lymphocyte to monocyte ratio or of the Th to Tc/s ratio does not impair the polyclonal activation of lymphocytes. In conclusion, we have characterized different patterns of correlated cellular peripheral immune disorders in rheumatoid arthritis, associated to pathological processes in conjunction with the immunsuppressive and anti-inflammatory action of methotrexate that might be relevant for further investigation of disease and further therapy outcome. We emphasize the special relation between the adaptive and innate immune system at the level of cell counts and proportions. The correlations between the peripheral abnormalities in the rheumatoid arthritis group are better highlighted by analyzing subgroups of patients characterized by particular values of the investigated parameters.     

On the evolution of erythrocyte programmed cell death: apoptosis of Rana esculenta nucleated red blood cells involves cysteine proteinase activation and mitochondrion permeabilization

Batracian Rana esculenta erythrocytes cell death induced by either calcium influx, or staurosporine, involves typical apoptotic phenotype. Our data reveal: (i) a drastic modification of the cell morphology with loss of the ellipsoidal form as assessed by phase contrast microscopy and scanning electron microscopy; (ii) an exposure of the phosphatidylserine residues in the outer leaflet of the cell membrane; (iii) a caspase-3-like activity; (iv) a mitochondrial membrane potential (Delta Psi m) loss; and (v) a chromatin condensation and fragmentation. Erythrocyte chromatin condensation and fragmentation are prevented by caspase and calpain peptide inhibitors. These inhibitors also prevent Delta Psi m loss supporting the idea that mitochondria is a central sensor for Rana erythrocytes cell death. Our observations highlight the conservation of the programmed cell death machinery in erythrocytes across kingdom.     

Matrix Production and Sporulation in Bacillus subtilis Biofilms Localize to Propagating Wave Fronts

Bacterial biofilms are surface-attached microbial communities encased in self-produced extracellular polymeric substances. Here we demonstrate that during the development of Bacillus subtilis biofilms, matrix production is localized to an annular front propagating at the periphery and sporulation to a second front at a fixed distance at the interior. We show that within these fronts, cells switch off matrix production and transition to sporulation after a set time delay of ～100 min. Correlation analyses of fluctuations in fluorescence reporter activity reveal that the fronts emerge from a pair of gene-expression waves of matrix production and sporulation. The localized expression waves travel across cells that are immobilized in the biofilm matrix in contrast to active cell migration or horizontal colony spreading. Our results suggest that front propagation arises via a local developmental program occurring at the level of individual bacterial cells, likely driven by nutrient depletion and metabolic by-product accumulation. A single-length scale and timescale couples the spatiotemporal propagation of both fronts throughout development. As a result, gene expression patterns within the advancing fronts collapse to self-similar expression profiles. Our findings highlight the key role of the localized cellular developmental program associated with the propagating front in describing biofilm growth.     

Comparative In Vivo Effects of Hemoglobin-Based Oxygen Carriers (HBOC) with Varying Prooxidant and Physiological Reactivity

A series of hemoglobin-based oxygen carrier candidates (HBOC), previously noted for their differences in prooxidative and physiological reactivity, were compared in terms of the negative effects displayed upon injection in Wistar rats. At the concentrations tested, antioxidant strategies based on albumin as well as based on rubrerythrin appear to offer observable physiological advantages.