Collagen receptors integrin alpha2beta1 and discoidin domain receptor 1 regulate maturation of the glomerular basement membrane and loss of integrin alpha2beta1 delays kidney fibrosis in COL4A3 knockout mice

2014 ◽  
Vol 34 ◽  
pp. 13-21 ◽  
Author(s):  
Diana Rubel ◽  
Jenny Frese ◽  
Maria Martin ◽  
Alexander Leibnitz ◽  
Rainer Girgert ◽  
...  
2013 ◽  
Vol 288 (23) ◽  
pp. 16738-16746 ◽  
Author(s):  
Vittorio Abbonante ◽  
Cristian Gruppi ◽  
Diana Rubel ◽  
Oliver Gross ◽  
Remigio Moratti ◽  
...  

Growing evidence demonstrates that extracellular matrices regulate many aspects of megakaryocyte (MK) development; however, among the different extracellular matrix receptors, integrin α2β1 and glycoprotein VI are the only collagen receptors studied in platelets and MKs. In this study, we demonstrate the expression of the novel collagen receptor discoidin domain receptor 1 (DDR1) by human MKs at both mRNA and protein levels and provide evidence of DDR1 involvement in the regulation of MK motility on type I collagen through a mechanism based on the activity of SHP1 phosphatase and spleen tyrosine kinase (Syk). Specifically, we demonstrated that inhibition of DDR1 binding to type I collagen, preserving the engagement of the other collagen receptors, glycoprotein VI, α2β1, and LAIR-1, determines a decrease in MK migration due to the reduction in SHP1 phosphatase activity and consequent increase in the phosphorylation level of its main substrate Syk. Consistently, inhibition of Syk activity restored MK migration on type I collagen. In conclusion, we report the expression and function of a novel collagen receptor on human MKs, and we point out that an increasing level of complexity is necessary to better understand MK-collagen interactions in the bone marrow environment.


Author(s):  
R.P. Nayyar ◽  
C.F. Lange ◽  
J. L. Borke

Streptococcal cell membrane (SCM) antiserum injected mice show a significant thickening of glomerular basement membrane (GBM) and an increase in mesangial matrix within 4 to 24 hours of antiserum administration (1,2,3). This study was undertaken to evaluate the incorporation of 3H proline into glomerular cells and GBM under normal and anti-SCM induced conditions. Mice were administered, intraperitoneally, 0.1 ml of normal or anti-SCM serum followed by a 10 µC/g body weight injection of 3H proline. Details of the preparation of anti-SCM (Group A type 12 streptococcal pyogenes) and other sera and injection protocol have been described elsewhere (2). After 15 minutes of isotope injection a chase of cold proline was given and animal sacrificed at 20 minutes, 1,2,4,8,24 and 48 hours. One of the removed kidneys was processed for immunofluorescence, light and electron microscopic radioautographic studies; second kidney was used for GBM isolation and aminoacid analysis.


Diabetes ◽  
1987 ◽  
Vol 36 (6) ◽  
pp. 758-763 ◽  
Author(s):  
M. P. Cohen ◽  
R. Saini ◽  
H. Klepser ◽  
L. G. Vasanthi

2010 ◽  
Vol 104 (11) ◽  
pp. 1038-1043 ◽  
Author(s):  
Carsten Hafer ◽  
Jan Kielstein ◽  
Marion Haubitz ◽  
Hermann Haller ◽  
Svjetlana Lovric ◽  
...  

SummaryIn critically ill patients, the massive release of angiopoietin-2 (Ang-2) from Weibel-Palade bodies interferes with protective angiopoietin-1 (Ang-1)/Tie2 signalling in endothelial cells, thus leading to vascular inflammation and subsequent organ-dysfunction. We hypothesised that plasma exchange (PE) is efficient for lowering excess Ang-2 levels in critically ill patients with thrombocytic microangiopathy (TMA) or anti-glomerular basement membrane (anti-GBM) disease. Plasma Ang-1 and Ang-2 were measured by immuno-luminometric assays in patients with TMA (n=9) or anti-GBM disease (n=4) before and after up to four PE sessions. Twenty apparently healthy volunteers served as controls. Median (IQR) plasma levels of Ang-2 were markedly increased in patients with TMA (7.3 (2.4–21.1) ng/ml) and anti-GBM disease (5.8 (3.4–7.0) ng/ml) compared to healthy controls (1.0 (0.9–1.4) ng/ml, p <0.001). Moreover, Ang-1 plasma levels were decreased in both, TMA (1.02 (0.62–1.62) ng/ml) and anti-GBM disease patients (0.74 (0.59–3.62) ng/ml) compared to healthy controls (2.5 (1.93–3.47) ng/ ml, p <0.005). During a total of 32 treatments, PE effectively lowered elevated mean (SD) Ang-2 plasma levels by 36.7 ± 19.6 % per treatment (p <0.0001), whereas low Ang-1 plasma levels remained unchanged (0.3 ± 58.5 %; p =0.147). Ang-2 levels declined to almost normal values during ≤4 PE treatments (Friedman´s test p <0.0001). PE is an effective method to remove excess circulating Ang-2. It remains to be elucidated if the removal of Ang-2 is crucial to ameliorate endothelial damage in critically ill patients with severely altered endothelial integrity.


Sign in / Sign up

Export Citation Format

Share Document