Dipeptidyl petidase-IV inhibitor (gemigliptin) inhibits tunicamycin-induced endoplasmic reticulum stress, apoptosis and inflammation in H9c2 cardiomyocytes.

The direct effects of dipeptidyl peptidase-IV (DPP-IV) inhibitors on endoplasmic reticulum (ER) stress-induced apoptosis and inflammation in cardiomyocytes have not been elucidated. H9c2 cell viability, which was reduced by tunicamycin, was increased after DPP-IV inhibitor gemigliptin treatment. Gemigliptin significantly decreased the tunicamycin-mediated increase in glucose regulated protein 78 (GRP78) expression and ER stress-mediated signaling molecules such as protein kinase RNA-like endoplasmic reticulum kinase (PERK)/C-EBP homologous protein (CHOP) and inositol-requiring enzyme 1α (IRE1α)/c-Jun N-terminal kinase (JNK)-p38. Furthermore, gemigliptin effectively induced Akt phosphorylation in a dose-dependent manner. Using flow cytometry and Hoechst staining, we showed that treatment with Akt inhibitor significantly blocked the anti-apoptotic effects mediated by gemigliptin. The reduction in tunicamycin-induced GRP78 level and PERK/CHOP pathway activity by gemigliptin was reversed after treatment with Akt inhibitor. In conclusion, gemigliptin effectively inhibited ER stress-induced apoptosis and inflammation in cardiomyocytes via Akt/PERK/CHOP and IRE1α/JNK-p38 pathways, suggesting its direct protective role in cardiovascular diseases.

Hwang HJ ，Jung TW ，Ryu JY ，Hong HC ，Choi HY ，Seo JA ，Kim SG ，Kim NH ，Choi KM ，Choi DS ，Baik SH ，Yoo HJ ... -  《-》

The dipeptidyl peptidase-IV inhibitor inhibits the expression of vascular adhesion molecules and inflammatory cytokines in HUVECs via Akt- and AMPK-dependent mechanisms.

Recently, dipeptidyl peptidase-IV (DPP-IV) inhibitor, a major anti-hyperglycemic agent, has received substantial attention as a possible therapeutic target for inflammatory diseases such as atherosclerosis. However, the direct molecular mechanisms through which DPP-IV inhibitor mediates anti-inflammatory effects in vascular endothelial cells have not been clarified. The effects of the DPP-IV inhibitor, gemigliptin, were analyzed in human umbilical vein endothelial cells (HUVECs) and THP-1 cells. Using Western blotting, we demonstrated that gemigliptin efficiently increased the level of AMP-activated protein kinase (AMPK) and Akt phosphorylation in a dose-dependent manner. The levels of lipopolysaccharide (LPS)-mediated phosphorylated nuclear factor-κB (NF-κB) and c-Jun N-terminal kinase (JNK) were significantly decreased after gemigliptin treatment. Furthermore, gemigliptin reduced LPS-induced expression of adhesion molecules and inflammatory cytokines such as vascular cell adhesion molecule-1 (VCAM-1), E-selectin, tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 (MCP-1), interleukin-1β (IL-1β), and IL-6 in HUVECs. In macrophage-like THP-1 cells, gemigliptin effectively inhibited LPS- and low-density lipoprotein (LDL)-induced foam cell formation. However, these anti-inflammatory and anti-atherosclerotic effects of gemigliptin in HUVECs and THP-1 cells were significantly reduced after treatment with an AMPK or an Akt inhibitor. Our results suggest that gemigliptin efficiently inhibited LPS-induced pro-inflammatory effects in vascular endothelial cells by attenuating NF-κB and JNK signaling via Akt/AMPK-dependent mechanisms. Therefore, the DPP-IV inhibitor, gemigliptin, may directly protect the vascular endothelium against inflammatory diseases such as atherosclerosis.

Hwang HJ ，Chung HS ，Jung TW ，Ryu JY ，Hong HC ，Seo JA ，Kim SG ，Kim NH ，Choi KM ，Choi DS ，Baik SH ，Yoo HJ ... -  《-》

Naringenin ameliorates hypoxia/reoxygenation-induced endoplasmic reticulum stress-mediated apoptosis in H9c2 myocardial cells: involvement in ATF6, IRE1α and PERK signaling activation.

Tang JY ，Jin P ，He Q ，Lu LH ，Ma JP ，Gao WL ，Bai HP ，Yang J ... -  《-》

Protocatechualdehyde protects oxygen-glucose deprivation/reoxygenation-induced myocardial injury via inhibiting PERK/ATF6α/IRE1α pathway.

Endoplasmic reticulum (ER) stress has been considered as a promising strategy in developing novel therapeutic agents for cardiovascular diseases through inhibiting cardiomyocyte apoptosis. Protocatechualdehyde (PCA) is a natural phenolic compound from medicinal plant Salvia miltiorrhiza with cardiomyocyte protection. However, the potential mechanism of PCA on cardiovascular ischemic injury is largely unexplored. Here, we found that PCA exerted markedly anti-apoptotic effect in oxygen-glucose deprivation/reoxygenation (OGD/R)-induced H9c2 cells (Rat embryonic ventricular H9c2 cardiomyocytes), which was detected by 3-(4, 5-dimethyl thiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT), lactate dehydrogenase (LDH), Hoechst 33258 and acridine orange/ethidium bromide (AO/EB) assays. PCA also obviously protected cardiomyocytes in myocardial fibrosis model of mice, which was determined by hematoxylin-eosin (HE) staining and TdT-mediated dUTP Nick-End Labeling (TUNEL) staining. Transcriptomics coupled with bioinformatics analysis revealed a complex pharmacological signaling network especially for PCA-mediated ER stress on cardiomyocytes. Further mechanism study suggested that PCA suppressed ER stress via inhibiting protein kinase R-like ER kinase (PERK), inositol-requiring enzyme1α (IRE1α), and transcription factor 6α (ATF6α) signaling pathway through Western blot, DIOC6 and ER-Tracker Red staining, leading to a protective effect against ER stress-mediated cardiomyocyte apoptosis. Taken together, our observations suggest that PCA is a major component from Salvia miltiorrhiza against cardiovascular ischemic injury by suppressing ER stress-associated PERK, IRE1α and ATF6α signaling pathways.

Wan YJ ，Wang YH ，Guo Q ，Jiang Y ，Tu PF ，Zeng KW ... -  《-》

The dipeptidyl peptidase-IV inhibitor gemigliptin alone or in combination with NVP-AUY922 has a cytotoxic activity in thyroid carcinoma cells.

Kim SH ，Kang JG ，Kim CS ，Ihm SH ，Choi MG ，Yoo HJ ，Lee SJ ... -  《-》