GLP-1 and Ghrelin Attenuate High Glucose/High Lipid-Induced Apoptosis and Senescence of Human Microvascular Endothelial Cells
Background/Aims: GLP-1 and ghrelin are common appetite-regulating hormones. Both have multiple functions beyond metabolic regulation. However, the effects of GLP-1 and ghrelin on endothelial biology are not fully understood. Here, we investigate the roles of GLP-1 and ghrelin in microvascular endothelial apoptosis and senescence. Methods: Human microvascular endothelial cells (HMECs) were exposed to high glucose/high lipid (HG/HL) conditions and treated with GLP-1 or ghrelin. Cellular apoptosis, senescence, and mitochondrial function were measured. In addition, the MAPK and Akt signaling pathways were examined. Results: Both GLP-1 and ghrelin treatment decreased the number of TUNEL-positive cells and inhibited caspase-3 and PARP cleavage and mitochondrial dysfunction in HG/HL-exposed HMECs. GLP-1, but not ghrelin decreased the number of β-galactosidase (β-gal)-positive cells. Furthermore, GLP-1 and ghrelin inhibited ERK1/2, JNK1/2, and p38 signaling. GLP-1 suppressed Akt signaling, but ghrelin had no effect. Moreover, JNK1/2 and p38 inhibitors, but not ERK1/2 and Akt inhibitors, decreased the number of TUNEL-positive cells. Additionally, only the Akt inhibitor decreased the number of β-gal-positive cells. Conclusion: These results demonstrate that GLP-1 and ghrelin inhibit mitochondrial dysfunction under HG/HL conditions, and suppress endothelial apoptosis via inhibiting JNK1/2 and p38 signaling; moreover, GLP-1 alleviates endothelial senescence via inactivating Akt signaling.