Warning: Undefined variable $zfal in C:\Inetpub\vhosts\kidney.de\httpdocs\mlpefetch.php on line 525
Deprecated: str_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in C:\Inetpub\vhosts\kidney.de\httpdocs\mlpefetch.php on line 525
Warning: Undefined variable $sterm in C:\Inetpub\vhosts\kidney.de\httpdocs\mlpefetch.php on line 530
Warning: Undefined variable $sterm in C:\Inetpub\vhosts\kidney.de\httpdocs\mlpefetch.php on line 531
 
English Wikipedia
Nephropedia Template TP (
Twit Text
DeepDyve
Pubget Overpricing |  
lüll
Role of GTPases in control of microvascular permeability Spindler V; Schlegel N; Waschke JCardiovasc Res 2010[Jul]; 87 (2): 243-53Inflammatory mediators increase vascular permeability primarily by formation of intercellular gaps between endothelial cells of post-capillary venules. Under these conditions, endothelial cell-cell contacts such as adherens and tight junctions open to allow paracellular fluid passage. Small guanosine triphosphatases (GTPases) from the ras superfamily, primarily Rho GTPases (RhoA, Rac1, Cdc42) or Rap1 are known to regulate cell adhesion, in part by reorganization of the junction-associated cortical actin cytoskeleton. In this review, we will discuss the role of small GTPases for the maintenance of microvascular barrier functions under resting conditions as well as under conditions of increased permeability and their involvement in signalling pathways downstream of both barrier-stabilizing and inflammatory mediators. Rac1 and Cdc42 are the main GTPases required for barrier maintenance and stabilization, whereas RhoA negatively regulates barrier properties under both resting and inflammatory conditions. For Rac1 and RhoA, contrary functions under certain conditions have also been described. However, Rac1-mediated barrier destabilization in microvascular endothelium appears to be largely restricted to conditions of enhanced endothelial cell migration and thus to be more closely related to angiogenesis rather than to inflammation. Recent studies revealed that cAMP signalling, which is well known to be barrier protective, enhances barrier functions in part via Rap1-mediated activation of Rac1 and Cdc42 as well as by inhibition of RhoA. Moreover, barrier-stabilizing mediators directly activate Rac1 and Cdc42 or increase cAMP levels. On the other hand, several barrier-disruptive components appear to increase permeability by reduced formation of cAMP, leading to both inactivation of Rac1 and activation of RhoA.|*Capillary Permeability[MESH]|Animals[MESH]|Body Fluids/*metabolism[MESH]|Endothelium, Vascular/*enzymology/immunology/physiopathology[MESH]|GTP Phosphohydrolases/*metabolism[MESH]|Humans[MESH]|Inflammation Mediators/metabolism[MESH]|Inflammation/enzymology/physiopathology[MESH]|Microvessels/*enzymology/immunology/physiopathology[MESH]|Signal Transduction[MESH] |
