scholarly journals CD59 protects glomerular endothelial cells from immune-mediated thrombotic microangiopathy in rats.

1998 ◽  
Vol 9 (4) ◽  
pp. 590-597 ◽  
Author(s):  
M Nangaku ◽  
C E Alpers ◽  
J Pippin ◽  
S J Shankland ◽  
K Kurokawa ◽  
...  
Keyword(s):  
Renal Artery ◽  
Thrombotic Microangiopathy ◽  
Regulatory Protein ◽  
Protective Role ◽  
Immune Mediated ◽  
Glomerular Endothelium ◽  
A Cell ◽  
Membrane Bound ◽  
Artery Perfusion

CD59 is a cell membrane-bound complement regulatory protein on glomerular cells that inhibits C5b-9 assembly and insertion. This report describes a recently developed model of immune thrombotic microangiopathy (TMA) induced by the renal artery perfusion of anti-glomerular endothelial cell (anti-GEN) antibody. To examine the role of CD59 in protecting the GEN from immune-mediated injury, rats underwent selective renal artery perfusion with F(ab')2 fragments of anti-CD59 monoclonal antibody to block CD59 activity or control mouse IgG followed by anti-GEN antibody or control goat IgG. Neutralization of CD59 in normal rats did not result in any significant functional or histologic changes. Perfusion with anti-CD59 did not change deposition of the pathogenic anti-GEN IgG used to induce the TMA model. However, neutralization of CD59 in the TMA model resulted in more C5b-9 formation in glomeruli, accompanied by increased platelet and fibrin deposition, more severe endothelial injury, and reduced renal function compared with the animals perfused with control F(ab')2 fragments. These results demonstrate directly that CD59 serves a protective role for GEN in this TMA model of rats, and confirm that C5b-9 formation has a critical pathogenic role in the mediation of the disease. CD59 may play an important role in protecting glomerular endothelium from other complement-mediated types of injury.

scholarly journals The Protective Role of Dormant Origins in Response to Replicative Stress

2018 ◽  
Vol 19 (11) ◽  
pp. 3569 ◽  
Author(s):  
Lilas Courtot ◽  
Jean-Sébastien Hoffmann ◽  
Valérie Bergoglio
Keyword(s):  
Dna Replication ◽  
Mammalian Cells ◽  
Genome Stability ◽  
Replication Timing ◽  
Protective Role ◽  
Entire Genome ◽  
Replicative Stress ◽  
A Cell ◽  
The Many

Genome stability requires tight regulation of DNA replication to ensure that the entire genome of the cell is duplicated once and only once per cell cycle. In mammalian cells, origin activation is controlled in space and time by a cell-specific and robust program called replication timing. About 100,000 potential replication origins form on the chromatin in the gap 1 (G1) phase but only 20–30% of them are active during the DNA replication of a given cell in the synthesis (S) phase. When the progress of replication forks is slowed by exogenous or endogenous impediments, the cell must activate some of the inactive or “dormant” origins to complete replication on time. Thus, the many origins that may be activated are probably key to protect the genome against replication stress. This review aims to discuss the role of these dormant origins as safeguards of the human genome during replicative stress.

Regulation of Rho protein binding to membranes by rhoGDI: inhibition of releasing activity by physiological ionic conditions

1999 ◽  
Vol 77 (1) ◽  
pp. 59-69 ◽  
Author(s):  
Diane Bilodeau ◽  
Sylvie Lamy ◽  
Richard R Desrosiers ◽  
Denis Gingras ◽  
Richard Béliveau
Keyword(s):  
Ionic Strength ◽  
Brush Border ◽  
Rat Kidney ◽  
Regulatory Protein ◽  
Rho Proteins ◽  
Glutathione S Transferase ◽  
Free System ◽  
Brush Border Membranes ◽  
A Cell ◽  
Membrane Bound

The Rho GDP dissociation inhibitor (GDI) is an ubiquitously expressed regulatory protein involved in the cycling of Rho proteins between membrane-bound and soluble forms. Here, we characterized the Rho solubilization activity of a glutathione S-transferase (GST) - GDI fusion protein in a cell-free system derived from rat kidney. Addition of GST-GDI to kidney brush border membranes resulted in the specific release of Cdc42 and RhoA from the membranes, while RhoB and Ras were not extracted. The release of Cdc42 and RhoA by GST-GDI was dose dependent and saturable with about 50% of both RhoA and Cdc42 extracted. The unextracted Rho proteins were tightly bound to membranes and could not be solubilized by repeated GST-GDI treatment. These results demonstrated that kidney brush border membranes contained two populations of RhoA and Cdc42. Furthermore, the GST-GDI solubilizing activity on membrane-bound Cdc42 and RhoA was abolished at physiological conditions of salt and temperature in all tissues examined. When using bead-immobilized GST-GDI, KCl did not reduced the binding of Rho proteins. However, washing brush border membranes with KCl prior treatment by GST-GDI inhibited the extraction of Rho proteins. Taken together, these results suggest that the binding of GDI to membrane-bound Cdc42 and RhoA occurs easily under physiological ionic strength conditions, but a complementary factor is required to extract these proteins from membranes. These observations suggest that the shuttling activity of GDI upon Rho proteins could be normally downregulated under physiological conditions.Key words: rhoGDI, rho proteins, ionic strength, kidney.

scholarly journals Manganese Induces Oxidative Stress, Redox State Unbalance and Disrupts Membrane Bound ATPases on Murine Neuroblastoma Cells In Vitro: Protective Role of Silymarin

2011 ◽  
Vol 36 (8) ◽  
pp. 1546-1557 ◽  
Author(s):  
Yassine Chtourou ◽  
Khaled Trabelsi ◽  
Hamadi Fetoui ◽  
Ghada Mkannez ◽  
Héla Kallel ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Redox State ◽  
Neuroblastoma Cells ◽  
Protective Role ◽  
Murine Neuroblastoma ◽  
Membrane Bound

C5b-9 membrane attack complex mediates endothelial cell apoptosis in experimental glomerulonephritis

2000 ◽  
Vol 278 (5) ◽  
pp. F747-F757 ◽  
Author(s):  
Jeremy Hughes ◽  
Masaomi Nangaku ◽  
Charles E. Alpers ◽  
Stuart J. Shankland ◽  
William G. Couser ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Regulatory Protein ◽  
Membrane Attack Complex ◽  
Fold Increase ◽  
Renal Perfusion ◽  
Con A ◽  
Immune Mediated ◽  
The Right ◽  
Endothelial Integrity

We studied the role of the C5b-9 membrane attack complex in two models of inflammatory glomerulonephritis (GN) initiated by acute glomerular endothelial injury in Piebold-viral-Glaxo (PVG) complement-sufficient rats (C+), C6-deficient rats (C6−), and rats systematically depleted of complement with cobra venom factor (CVF). GN was induced by performing a left nephrectomy and selectively perfusing the right kidney with either 1) the lectin concanavalin A (Con A) followed by complement-fixing anti-Con A (Con A GN) or 2) purified complement-fixing goat anti-rat glomerular endothelial cell (GEN) antibody [immune-mediated thrombotic microangiopathy (ITM)]. Comparable levels of GEN apoptosis were detected in C+ animals in both models. CVF administration reduced GEN apoptosis by 10- to 12-fold. GEN apoptosis was C5b-9 dependent because PVG C6− rats were protected from GEN loss. Furthermore, functional inhibition of the cell surface complement regulatory protein CD59 by renal perfusion with anti-CD59 antibody in ITM resulted in a 3.5-fold increase in GEN apoptosis. Last, in Con A GN, abrogation of GEN apoptosis preserved endothelial integrity and renal function. This study demonstrates the specific role of C5b-9 in the induction of GEN apoptosis in experimental inflammatory GN, a finding with implications for diseases associated with the presence of antiendothelial cell antibodies.

Hemolytic Uremic Syndrome Is an Immune Mediated Disease: Role of Anti-CD36 Antibodies.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3990-3990
Author(s):  
Gail Rock ◽  
William Clark ◽  
Marion Sternbach ◽  
Maria Kolajova ◽  
Peter McLaine
Keyword(s):  
Hemolytic Uremic Syndrome ◽  
Molecular Mimicry ◽  
Platelet Lysate ◽  
Mechanism Of Formation ◽  
Normal Platelet ◽  
Immune Mediated ◽  
Uremic Syndrome ◽  
Membrane Bound ◽  
Immunological Pathogenesis

Abstract Hemolytic uremic syndrome is a disorder in which platelet microthrombi are formed which have a particular propensity to deposit in the kidney microvasculature resulting in impaired renal function and thrombocytopenia. The mechanism of formation of these microthrombi is not known. In this study, we showed that plasma from five adult and six pediatric cases of HUS caused aggregation and release of adenosine triphosphate from normal platelets. The plasma reacted against platelet lysate in a protein blot and all samples showed reactivity against a band at 88kDa corresponding to the membrane antigen CD36. This was confirmed by probing with Mo91, a monoclonal antibody to CD36. CD36 was also identified in the immune complex formed by incubation of patient plasmas with normal platelet lysate. In other studies, bands of 32kDa and 7.7kDa were obtained when purified verotoxin was protein blotted and probed with either patient plasma or with anti-CD36 antibody Mo91 suggesting structural homologies between CD36 and verotoxin. The data support the concept of an immunological pathogenesis for HUS and suggest that molecular mimicry involving one or both of the homologous domains in membrane-bound CD36 and verotoxin lead to the development of antibodies capable of inducing the pathophysiological events characteristic of HUS.

scholarly journals Harnessing biomolecular condensates in living cells

2019 ◽  
Vol 166 (1) ◽  
pp. 13-27 ◽  
Author(s):  
Hideki Nakamura ◽  
Robert DeRose ◽  
Takanari Inoue
Keyword(s):  
Living Cells ◽  
Technological Advance ◽  
Liquid Droplets ◽  
Molecular Tools ◽  
Rna Molecules ◽  
Cell Functions ◽  
Pathological Conditions ◽  
A Cell ◽  
Membrane Bound

Abstract As part of the ‘Central Dogma’ of molecular biology, the function of proteins and nucleic acids within a cell is determined by their primary sequence. Recent work, however, has shown that within living cells the role of many proteins and RNA molecules can be influenced by the physical state in which the molecule is found. Within living cells, both protein and RNA molecules are observed to condense into non-membrane-bound yet distinct structures such as liquid droplets, hydrogels and insoluble aggregates. These unique intracellular organizations, collectively termed biomolecular condensates, have been found to be vital in both normal and pathological conditions. Here, we review the latest studies that have developed molecular tools attempting to recreate artificial biomolecular condensates in living cells. We will describe their design principles, implementation and unique characteristics, along with limitations. We will also introduce how these tools can be used to probe and perturb normal and pathological cell functions, which will then be complemented with discussions of remaining areas for technological advance under this exciting theme.

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