Adenosine prevents TNFα‐induced decrease in endothelial mitochondrial mass via activation of eNOS‐PGC‐1α regulatory axis (664.5)

Abstract

To gain insight into the potential role of endothelial mitochondrial function and biogenesis in the preconditioning effects of adenosine (Ado), we incubated human microvascular endothelial cells (HMEC‐1) with TNFα in the presence or absence of Ado. TNFα produced time and dose‐dependent decreases in mitochondrial membrane potential, cellular ATP levels, and mitochondrial mass, which preceded an increase in apoptosis. These effects were prevented by co‐incubation with Ado, an NO donor (detaNO), a guanylate cyclase (GC) activator (YC‐1), or a cell‐permeant cGMP analog (8‐Br‐cGMP). The effects of Ado were blocked by a NO synthase inhibitor (L‐NIO), a soluble guanylate cyclase inhibitor (ODQ), a morpholino antisense oligonucleotide to eNOS, or siRNA knockdown of PGC‐1α. DetaNO reversed the the effect of eNOS knockdown, as did YC‐1 and 8‐Br‐cGMP, while the effect of detaNO was blocked by ODQ. Both detaNO’s and 8‐Br‐cGMP’s effects were prevented by siRNA to PGC‐1α. TNFα also decreased expression of eNOS and PGC‐1α, which was reversed by Ado. DetaNO, but not Ado, rescued expression of PGC‐1α in cells in which eNOS expression was knocked down by eNOS antisense treatment. These results support the existence of an adenosine‐triggered, mito‐and cytoprotective mechanism dependent upon an eNOS‐PGC‐1α regulatory pathway, which acts to preserve endothelial mitochondrial function and mass in the face of inflammatory challenge.Grant Funding Source: Supported by NIH grants: AA014945 & HL095486