Autophagy Protects Against Senescence and Apoptosis via the RAS-Mitochondria in High-Glucose-Induced Endothelial Cells

Background/Aims: Endothelial-mesenchymal transition (EndMT) has been shown to take part in the generation and progression of diverse diseases, involving a series of changes leading to a loss of their endothelial characteristics and an acquirement of properties typical of mesenchymal cells. Low-intensity pulsed ultrasound (LIPUS) is a new therapeutic option that has been successfully used in fracture healing. However, whether LIPUS can inhibit oxidative stress-induced endothelial cell damages through inhibiting EndMT remained unknown. This study aimed to investigate the protective effects of LIPUS against oxidative stress-induced endothelial cell damages and the underlying mechanisms. Methods: EndMT was induced by H₂O₂ (100 µm for seven days). Human aortic endothelial cells (HAECs) were exposed to H₂O₂ with or without LIPUS treatment for seven days. The expression of EndMT markers (CD31, VE-cadherin, FSP1 and α-SMA) were analyzed. The levels of total and phosphorylated PI3K and AKT proteins were detected by Western Blot analysis. Cell chemotaxis was determined by wound healing and transwell assay. Results: LIPUS relieved EndMT by decreasing ROS accumulation and increasing activation of the PI3K signaling cascade. LIPUS alleviated the migration of EndMT-derived mesenchymal-like cells through reducing extracellular matrix (ECM) deposition that is associated with matrix metallopeptidase (MMP) proteolytic activity and collagen production. Conclusion: LIPUS produces cytoprotective effects against oxidative injuries to endothelial cells through suppressing the oxidative stress-induced EndMT, activating the PI3K/AKT pathway under oxidative stress, and limiting cell migration and excessive ECM deposition.

Section: Introductionmentioning

confidence: 99%

Low-Intensity Pulsed Ultrasound Prevents the Oxidative Stress Induced Endothelial-Mesenchymal Transition in Human Aortic Endothelial Cells

Zhang

Ren

et al. 2018

“…It has been reported that increased oxidative injury in diabetic hearts may trigger the activation of stress signalling pathways, facilitating cardiomyocyte cell death [26,27]. However, recent evidence also suggests that, in addition to apoptosis, other processes, such as autophagy, may also be involved in controlling cell death in the pathogenesis of diabetic cardiomyopathy [28].…”

Section: Discussionmentioning

confidence: 99%

Autophagy Plays a Protective Role in Advanced Glycation End Product-Induced Apoptosis in Cardiomyocytes

Zhou²,

Lu³

et al. 2015

Background/Aims: To investigate the effect of advanced glycation endproduct-induced autophagy in rat cardiomyocytes and to identify the role of autophagy in advanced glycation end product-induced cell apoptosis. Methods: After cultured rat cardiomyocytes were treated with advanced glycation end products (AGEs), protein expression was detected by western blotting, autophagosomes were observed by electron microscopy, the cell apoptotic rate was determined by flow cytometry, and cell variability was quantified by the MTT assay. Results: After cultured cardiomyocytes were treated with AGEs, the level of autophagy-associated protein LC3-II was up-regulated and SQSTM1/p62 was down-regulated; the number of autophagosomes was increased. Compared with the control group, the apoptotic rate of cardiomyocytes increased, and the cardiomyocyte viability was decreased in the AGE-treated group. Furthermore, pretreating cells with3-MA, an autophagy inhibitor, could enhance these effects. Treatment with AGEs activated phospho-ERK, phospho-JNK, and phospho-p38/MAPK but inhibited phospho-Akt and phospho-mTOR. Pretreatment with an ERK inhibitor and an Akt activator could inhibit AGE-induced autophagy, demonstrating that AGEs induce autophagy in cardiomyocytes through the ERK and Akt signalling pathways. Conclusion: AGEs can induce autophagy through the PI3K/AKT/mTOR and ERK signalling pathways and induce apoptosis through the PI3K/AKT/mTOR and p38/MAPK signalling pathways in rat cardiomyocytes. Autophagy plays a protective role in AGE-induced apoptosis in cardiomyocytes.

“…Autophagy flux is increased in the endothelial cells after high-glucose or nutrient deprivation and aortic endothelium of diabetic rat model [5,6]. An experimental approach to reproduce nutrient deprivation consists of the removal of growth factors or serum deprivation [7,8].…”

Section: Introductionmentioning

confidence: 99%

Inhibition of Autophagy by Chloroquine Stimulates Nitric Oxide Production and Protects Endothelial Function during Serum Deprivation

Pestana

Oishi²,

Salistre-Araújo³

et al. 2015

Background/Aims: Autophagy plays a fundamental role in cell survival under stress conditions such as nutrient deprivation. Decreased nitric oxide (NO) production, which may contribute to vascular dysfunction, is one of the consequences of autophagy in endothelial cells. The antimalarial drug chloroquine (CLQ) inhibits autophagy by blocking autophagosome formation and has been proposed as adjuvant chemotherapy in other diseases. Methods: Autophagy was induced by serum deprivation in Human Umbilical Vascular Endothelial Cells (HUVEC) as demonstrated by formation of Acidic Vesicular Organelles (AVOs), conversion of Microtubule-associated protein 1 light chain (LC3), and Sequestosome-1 (SQTM1/p62) degradation. Using endothelium-dependent vasorelaxation assays, intracellular NO production in an ex vivo rat aortic ring model pre-constricted with phenylephrine was estimated along with DAF-2 DA cell membrane-permeable NO sensitive fluorescent dye. Results: The inhibition of autophagy by CLQ restored NO levels, protected against superoxide generation and preserved morphology as well as proliferation of HUVEC under serum deprivation. Interestingly, the incubation of rat aortic rings with CLQ resulted in endothelium-dependent relaxation mediated by the increase of NO. Conclusion: These findings emphasize the importance of autophagy in endothelial function and demonstrate the potential use of autophagy inhibitors to protect vascular function during nutrient deprivation.