DJ‐1 Alleviates Angiotensin II‐Induced Endothelial Progenitor Cell Damage by Activating the PPARγ/HO‐1 Pathway

There is evidence that angiotensin II (Ang II) may impair the functions of endothelial progenitor cells (EPCs). It was revealed that DJ‐1 could resist oxidative stress. In this study, we investigated whether DJ‐1 could protect EPCs against Ang II‐induced cell damage. The proliferation and migration of EPCs were strongly reduced in the Ang II group and were increased by overexpression of DJ‐1. Western blotting indicated that the increased expression of the senescence marker β‐galactosidase and decreased expression of adhesion molecules (ICAM‐1, VCAM‐1) induced by Ang II were reversed after Ad‐DJ‐1 transfection. The reduced angiogenic capacity of EPCs caused by Ang II was also improved after Ad‐DJ‐1 transfection. Moreover, Ang II significantly increased the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and inflammatory cytokines (TNF‐α and IL‐1β), reduced the levels of superoxide dismutase (SOD), glutathione (GSH), and these were reversed by Ad‐DJ‐1 transfection. Expression of peroxisome proliferator‐activated receptor‐γ (PPARγ) and heme oxygenase (HO‐1) was increased by DJ‐1. Therefore, HO‐1 siRNA were constructed and transfected into EPCs, and the results showed that HO‐1 siRNA transfection inhibited the effects of DJ‐1 on EPC function. Thus, our study implies that DJ‐1 may protect EPCs against Ang II‐induced dysfunction by activating the PPARγ/HO‐1. J. Cell. Biochem. 119: 392–400, 2018. © 2017 Wiley Periodicals, Inc.     

7-Ketocholesterol enhances the expression of adhesion molecules on human aortic endothelial cells by increasing the production of reactive oxygen species

Abstract

The aim of the present study was to assess the expression of intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), monocytic adhesion of human aortic endothelial cells (HAECs), and the production of intracellular reactive oxygen species (ROS), when HAECs were stimulated by 7-ketocholesterol. 7-ketocholesterol enhances surface expression of ICAM-1 and VCAM-1 as determined by EIA, induces their mRNA expression by RT-PCR, and stimulates adhesiveness of HAECs to U937 monocytic cells. We confirmed up-regulation of ROS production of HAECs treated with 7-ketocholesterol. Although the surface expression of ICAM-1 and VCAM-1 on HAECs treated with 7-ketocholesterol increased in a time-dependent manner, α-tocopherol inhibited this increase of the surface expression of ICAM-1 and VCAM-1. In the monocytic adhesion assay, adhesion of U937 to HAECs treated with 7-ketocholesterol was enhanced, but monoclonal anti-ICAM-1 and VCAM-1 antibodies reduced the endothelial adhesiveness. In conclusion, this study suggests that the endothelial adhesiveness to monocytic cells that was increased by 7-ketocholesterol was associated with enhanced expression of ICAM-1 and VCAM-1 mediated by ROS production.     

The PPARδ ligand L-165041 inhibits VEGF-induced angiogenesis, but the antiangiogenic effect is not related to PPARδ

Peroxisome proliferator-activated receptor (PPAR)δ is known to be expressed ubiquitously and involved in lipid and glucose metabolism. Recent studies have demonstrated that PPARδ is expressed in endothelial cells (ECs) and plays a potential role in endothelial survival and proliferation. Although PPARα and PPARγ are well recognized to play anti-inflammatory, antiproliferative, and antiangiogenic roles in ECs, the general effect of PPARδ on angiogenesis in ECs remains unclear. Thus, we investigated the effect of the PPARδ ligand L-165041 on vascular EC proliferation and angiogenesis in vitro as well as in vivo. Our data show that L-165041 inhibited VEGF-induced cell proliferation and migration in human umbilical vein ECs (HUVECs). L-165041 also inhibited angiogenesis in the Matrigel plug assay and aortic ring assay. Flow cytometric analysis indicated that L-165041 reduced the number of ECs in the S phase and the expression levels of cell cycle regulatory proteins such as cyclin A, cyclin E, CDK2, and CDK4; phosphorylation of the retinoblastoma protein was suppressed by pretreatment with L-165041. We confirmed whether these antiangiogenic effects of L-165041 were PPARδ-dependent using GW501516 and PPARδ siRNA. GW501516 treatment did not inhibit VEGF-induced angiogenesis, and transfection of PPARδ siRNA did not reverse this antiangiogenic effect of L-165041, suggesting that the antiangiogenic effect of L-165041 on ECs is PPARδ-independent. Together, these data indicate that the PPARδ ligand L-165041 inhibits VEGF-stimulated angiogenesis by suppressing the cell cycle progression independently of PPARδ. This study highlights the therapeutic potential of L-165041 in the treatment of many disorders related to pathological angiogenesis.