MiR-135a Protects Vascular Endothelial Cells Against Ventilator-Induced Lung Injury by Inhibiting PHLPP2 to Activate PI3K/Akt Pathway

Abstract

Background/Aims: Loss of endothelial barrier function plays an important role in the development of ventilator-induced lung injury (VILI). This study aimed to investigate the effects of miR135a on VILI in a model of mechanical stretch (MS)-induced human umbilical vein endothelial cell (HUVEC) injury. Methods: HUVECs were randomly assigned to 7 groups: blank, negative control (NC), NC+MS, miR135a over-expression (mi-miR135a), mi-miR135a + MS, miR135a silencing (si-miR135a) and si-miR135a + MS groups. MS was induced by subjecting cells to cyclic stretch at 20% stretch for 4 h. After 24 h, levels of reactive oxygen species (ROS) were measured by DCFH-DA fluorescence intensity. Apoptosis was measured using annexin V-FITC/propidium iodide assay with flow cytometry. Inflammatory cytokine levels were determined by ELISA. Barrier integrity was determined using FITC-conjugated dextran assay. Expression levels of PI3K, p-PI3K, Akt, p-Akt, Bcl-2 and Bax were examined using western blotting. The interaction between miR135a and PHLPP2 was evaluated by dual-luciferase reporter assay. Results: Our results showed that MS reduced cell numbers, increased the number of apoptotic cells, increased ROS, barrier dysfunction and inflammatory cytokines in HUVECs, and reduced p-PI3K and p-Akt expression; silencing of miR135a worsened MS-induced HUVEC injury. However, miR135a over-expression protected HUVECs against MS-induced increases in apoptotic cells, ROS, barrier dysfunction and inflammatory cytokines, which were accompanied by activation of the PI3K/Akt signaling pathway. Simultaneous silencing of miR135a and PHLPP2 partially salvaged the effects of miR135a silencing, and miR135a was found to interact with PHLPP2. Conclusion: miR135a may protect HUVECs from MS-induced injury by inhibiting PHLPP2 to activate PI3k/Akt signaling pathway.

Upregulation of MicroRNA-21 promotes tumorigenesis of prostate cancer cells by targeting KLF5

“…Increased apoptosis of cancer cells is induced by the increased pro-apoptotic proteins (Bax, Bak) and the decreased antiapoptotic proteins (Bcl-2,Bcl-w,Bcl-X L ,Bfl-1,Mcl-1), Bcl-2 and Bax are well demonstrated by many studies. [23][24][25] In our study, the increased expression of Bax and the decreased expression of Bcl-2 were in line with the changes in apoptosis induced by downregulation of miR-21in the corresponding cancer cells. A number of targets of miR-21 have been reported in PCa including PTEN.…”

RETRACTED ARTICLE: SNHG6 modulates oxidized low-density lipoprotein-induced endothelial cells injury through miR-135a-5p/ROCK in atherosclerosis

“…In addition, the protective role of miR-135a in macrophages and ECs has been also confirmed. For example, miR-135a protected HUVECs against mechanical stretch (MS)-induced cell apoptosis, oxidative stress, and inflammatory reaction by interacting with PHLPP2 and inducing the activation of PI3K/Akt pathway [26]. MiR-135a overexpression repressed macrophage-derived foam cell formation, oxidative stress and inflammatory events via downregulating toll-like receptor 4 (TLR4) in atherosclerosis [17].…”

MicroRNA-135a Protects Against Ethanol-Induced Apoptosis in Neural Crest Cells and Craniofacial Defects in Zebrafish by Modulating the Siah1/p38/p53 Pathway

“…For example, a study by Dong et al, indicated that, by targeting HIF-1α, miR-135a downregulated pro-apoptotic genes Bax and Bad, upregulated anti-apoptotic gene Bcl-2, resulting in increased proliferation and reduced apoptosis of astrocytes in the bacterial meningitis rat models ( Dong et al, 2019 ). Upregulation of miR-135a also protected human umbilical vein endothelial cells against mechanical stretch-induced increases in apoptosis and ventilator-induced lung injury through activating PI3K/Akt signaling pathway by targeting PH domain leucine-rich repeat-containing protein phosphatase 2 (PHLPP2) ( Yan et al, 2018 ). In the present study, we have shown that ethanol-induced downregulation of miR-135a resulted in the upregulation of Siah1 and that overexpression of miR-135a significantly reduced ethanol-induced upregulation of Siah1, indicating that downregulation of miR-135a contributes to ethanol-induced upregulation of Siah1 in NCCs and zebrafish embryos.…”

“…Studies have also shown that miR-135a can promote proliferation and inhibit apoptosis of astrocytes in the bacterial meningitis rat models ( Dong et al, 2019 ). Overexpression of miR-135a can also protect human umbilical vein endothelial cells against mechanical stretch-induced increases in apoptosis and ventilator-induced lung injury ( Yan et al, 2018 ). In addition, Siah1 has been identified as a target of miR-135a in HeLa cells and mouse zygotes ( Pang et al, 2011 ).…”