Hepatocyte growth factor prevents advanced glycation end products-induced injury and oxidative stress through a PI3K/Akt-dependent pathway in human endothelial cells.

Aims: Advanced glycation end products (AGEs) trigger an oxidative reaction which then accelerates endothelial cell apoptosis; this is a critical event in the process of diabetic vascular complications. We previously demonstrated that hepatocyte growth factor (HGF) protects human endothelial cells against AGE-induced injury. The present study was designed to investigate the possible involvement of MAPK and PI3K/Akt signaling in the action of HGF.

Main Methods: HUVECs were treated with AGEs in the presence or absence of HGF. For detection of apoptosis, the morphological Acridine Orange staining, flow cytometry, and caspase-3 activity assay were used. Generation of reactive oxygen species (ROS) and the change in mitochondrial membrane potential were measured using flow cytometry and fluorescence immune analysis. The activation of MAPK and Akt was assayed by Western blot.

Key Findings: HGF exerted its prosurvival effect by inhibiting the overproduction of intracellular ROS and the depolarization of mitochondrial membrane, induced by AGEs. HGF-induced survival correlated with Akt activity and was inhibited by the specific PI3K inhibitor. ERK also was activated by HGF and rescued cells from apoptosis, although the cytoprotective effect was less marked than for PI3K/Akt. HGF-mediated survival was independent of JNK and p38MAPK pathways. Furthermore, blocking the PI3K and Akt activities with PI3K inhibitors or transfection of HUVECs with the dominant-negative p85 or Akt effectively abolished the inhibition of the intracellular ROS production and mitochondrial damage.

Significance: Our studies suggest that HGF, via PI3K/Akt signaling, prevents AGE-induced apoptosis and oxidative stress through the inhibition of mitochondrial damage in HUVECs.