Targeting plasminogen activator inhibitor-1 in tetracycline-induced pleural injury in rabbits.

Am J Physiol Lung Cell Mol Physiol 2018 01 31;314(1):L54-L68. Epub 2017 Aug 31.

Texas Lung Injury Institute, The University of Texas Health Science Center at Tyler , Tyler, Texas.

Elevated active plasminogen activator inhibitor-1 (PAI-1) has an adverse effect on the outcomes of intrapleural fibrinolytic therapy (IPFT) in tetracycline-induced pleural injury in rabbits. To enhance IPFT with prourokinase (scuPA), two mechanistically distinct approaches to targeting PAI-1 were tested: slowing its reaction with urokinase (uPA) and monoclonal antibody (mAb)-mediated PAI-1 inactivation. Removing positively charged residues at the "PAI-1 docking site" (RHRGGS→AAAAAA) of uPA results in a 60-fold decrease in the rate of inhibition by PAI-1. Mutant prourokinase (0.0625-0.5 mg/kg; n = 12) showed efficacy comparable to wild-type scuPA and did not change IPFT outcomes ( P > 0.05). Notably, the rate of PAI-1-independent intrapleural inactivation of mutant uPA was 2 times higher ( P < 0.05) than that of the wild-type enzyme. Trapping PAI-1 in a "molecular sandwich"-type complex with catalytically inactive two-chain urokinase with SerAla substitution (S195A-tcuPA; 0.1 and 0.5 mg/kg) did not improve the efficacy of IPFT with scuPA (0.0625-0.5 mg/kg; n = 11). IPFT failed in the presence of MA-56A7C10 (0.5 mg/kg; n = 2), which forms a stable intrapleural molecular sandwich complex, allowing active PAI-1 to accumulate by blocking its transition to a latent form. In contrast, inactivation of PAI-1 by accelerating the active-to-latent transition mediated by mAb MA-33B8 (0.5 mg/kg; n = 2) improved the efficacy of IPFT with scuPA (0.25 mg/kg). Thus, under conditions of slow (4-8 h) fibrinolysis in tetracycline-induced pleural injury in rabbits, only the inactivation of PAI-1, but not a decrease in the rate of its reaction with uPA, enhances IPFT. Therefore the rate of fibrinolysis, which varies in different pathologic states, could affect the selection of PAI-1 inhibitors to enhance fibrinolytic therapy.

Download full-text PDF

Source
http://dx.doi.org/10.1152/ajplung.00579.2016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6048456PMC
January 2018

Publication Analysis

Top Keywords

injury rabbits
12
pleural injury
12
tetracycline-induced pleural
12
pai-1
9
fibrinolytic therapy
8
inactivation pai-1
8
decrease rate
8
efficacy ipft
8
ipft scupa
8
00625-05 mg/kg
8
activator inhibitor-1
8
plasminogen activator
8
ipft
7
mg/kg
6
two-chain urokinase
4
urokinase serala
4
substitution s195a-tcupa
4
serala substitution
4
inactive two-chain
4
forms stable
4

Similar Publications