Oxidative stress has been demonstrated to play a causal role in different vascular diseases, such as hypertension, diabetic vasculopathy, hypercholesterolemia and atherosclerosis. Indeed, increased reactive oxygen species (ROS) production is known to impair endothelial and vascular smooth muscle cell functions, contributing to the development of cardiovascular diseases. MicroRNAs (miRNAs) are non-coding RNA molecules that modulate the stability and/or the translational efficiency of target messenger RNAs. They have been shown to be modulated in most biological processes, including in cellular responses to redox imbalance. In particular, miR-200 family members play a crucial role in oxidative-stress dependent endothelial dysfunction, as well as in cardiovascular complications of diabetes and obesity. In addition, different miRNAs, such as miR-210, have been demonstrated to play a key role in mitochondrial metabolism, therefore modulating ROS production and sensitivity. In this review, we will discuss miRNAs modulated by ROS or involved in ROS production, and implicated in vascular diseases in which redox imbalance has a pathogenetic role.

Aims: Reactive oxygen species (ROS) play a pivotal role in different pathologic conditions, including ischemia, diabetes, and aging. We previously showed that ROS enhance miR-200c expression, causing endothelial cell (EC) apoptosis and senescence. Herein, we dissect the interaction among miR-200c and three strictly related proteins that modulate EC function and ROS production: sirtuin 1 (SIRT1), endothelial nitric oxide synthase (eNOS), and forkhead box O1 (FOXO1). Moreover, the role of miR-200c on ROS modulation was also investigated. Results: We demonstrated that miR-200c directly targets SIRT1, eNOS, and FOXO1; via this mechanism, miR-200c decreased NO and increased the acetylation of SIRT1 targets, that is, FOXO1 and p53. FOXO1 acetylation inhibited its transcriptional activity on target genes, that is, SIRT1 and the ROS scavengers, catalase and manganese superoxide dismutase. In keeping, miR-200c increased ROS production and induced p66Shc protein phosphorylation in Ser-36; this mechanism upregulated ROS and inhibited FOXO1 transcription, reinforcing this molecular circuitry. These in vitro results were validated in three in vivo models of oxidative stress, that is, human skin fibroblasts from old donors, femoral arteries from old mice, and a murine model of hindlimb ischemia. In all cases, miR-200c was higher versus control and its targets, that is, SIRT1, eNOS, and FOXO1, were downmodulated. In the mouse hindlimb ischemia model, anti-miR-200c treatment rescued these targets and improved limb perfusion. Innovation and Conclusion: miR-200c disrupts SIRT1/FOXO1/eNOS regulatory loop. This event promotes ROS production and decreases NO, contributing to endothelial dysfunction under conditions of increased oxidative stress such as aging and ischemia. Antioxid. Redox Signal . 27, 328–344.

Background— Oxidative stress plays a pivotal role in ischemia and ischemia/reperfusion injury. Because p66 ^ShcA -null (p66 ^ShcA −/−) mice exhibit both lower levels of intracellular reactive oxygen species and increased resistance to cell death induced by oxidative stress, we investigated whether tissue damage that follows acute ischemia or ischemia/reperfusion was altered in p66 ^ShcA −/− mice. Methods and Results— Unilateral hindlimb ischemia was induced by femoral artery dissection, and ischemia/reperfusion was induced with an elastic tourniquet. Both procedures caused similar changes in blood perfusion in p66 ^ShcA wild-type (p66 ^ShcA wt) and p66 ^ShcA −/− mice. However, significant differences in tissue damage were found: p66 ^ShcA wt mice displayed marked capillary density decrease and muscle fiber necrosis. In contrast, in p66 ^ShcA −/− mice, minimal capillary density decrease and myofiber death were present. When apoptosis after ischemia was assayed, significantly lower levels of apoptotic endothelial cells and myofibers were found in p66 ^ShcA −/− mice. In agreement with these data, both satellite muscle cells and endothelial cells isolated from p66 ^ShcA −/− mice were resistant to apoptosis induced by simulated ischemia in vitro. Lower apoptosis levels after ischemia in p66 ^ShcA −/− cells correlated with decreased levels of oxidative stress both in vivo and in vitro. Conclusions— p66 ^ShcA plays a crucial role in the cell death pathways activated by acute ischemia and ischemia/reperfusion, indicating p66 ^ShcA as a potential therapeutic target for prevention and treatment of ischemic tissue damage.

Increased oxidative stress and reduced nitric oxide (NO) bioavailability play a causal role in endothelial cell dysfunction occurring in the vasculature of diabetic patients. In this review, we summarized the molecular mechanisms underpinning diabetic endothelial and vascular dysfunction. In particular, we focused our attention on the complex interplay existing among NO, reactive oxygen species (ROS), and one crucial regulator of intracellular ROS production,p66Shcprotein.

Expression of the FGFR2 mesenchymal splicing variant in epithelial cells drives epithelial-mesenchymal transition