Abstract 11114: Effects of Epigenetic Modifiers on Lps-induced Enos/rho Signaling And Restoration of Adherens Junction Integrity and Endothelial Barrier Protection
Background and Objective: Impairment of the regulation of tissue fluid homeostasis and migration of blood cells across the endothelial barrier are crucial factors in the pathogenesis of acute lung injury (ALI). Thus, a goal for treatment of ALI is to target the pathways that lead to profound dysregulation of the restrictive endothelial barrier, and thereby restore lung microvascular endothelial barrier function and inhibit protein-rich tissue fluid accumulation. Here we test the hypothesis that epigenetic modifiers TSA (Trichostatin-A, a HDAC inhibitor) and Aza (5-aza-2-deoxycytidine, a DNA methyl transferase inhibitor) together inhibit the LPS/thrombin induced eNOS/RhoA signaling and restore AJ integrity and diminished endothelial hyperpermeability.
Methods and Results: The signaling, AJ integrity and endothelial permeability were assessed by RT-PCR and western blot analysis; transendothelial resistance (TER) and lung endothelial permeability were measured by capillary filtration coefficient (Kfc). We also examined the effect of TSA+Aza in LPS-induced macrophages by RT-PCR array for inflammatory cytokines. Our data show that combination of TSA+Aza is more effective in inhibiting LPS-induced lung hyperpermeability. Injection of LPS (ip) led to a significant increase of lung microvascular permeability Kfc in mice compared with basal condition. Strikingly, these increases were significantly reduced in mice treated with TSA+Aza than either alone. To confirm our findings from mice, we used an in vitro culture system of TER to determine the effect of TSA+Aza on thrombin-induced change in resistance over the mouse lung microvascular endothelial cells (MLVECs). TSA+Aza treatment ameliorated the thrombin-induced endothelial barrier disruption. The qRT-PCR array data show that the treatment of Aza+TSA decreases the levels of LPS induced inflammatory cytokines in macrophage cells.
Conclusions: Our data indicate, for the first time, that epigenetic modifiers (TSA+Aza) exert a protective role in preventing lung microvascular hyperpermeability and endothelial barrier disruption in LPS-induced lung injury, and thus have great potential as novel anti-inflammatory therapeutic agents against infection associated pulmonary injury.
- © 2012 by American Heart Association, Inc.