scholarly journals Restoration of autophagy in endothelial cells from patients with diabetes mellitus improves nitric oxide signaling

2016 ◽  
Vol 247 ◽  
pp. 207-217 ◽  
Author(s):  
Jessica L. Fetterman ◽  
Monica Holbrook ◽  
Nir Flint ◽  
Bihua Feng ◽  
Rosa Bretόn-Romero ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Diabetes Mellitus ◽  
Endothelial Cells ◽  
Nitric Oxide Signaling ◽  
Patients With Diabetes

Abstract 12185: Restoration of Autophagy in Endothelial Cells From Patients With Diabetes Improves Nitric Oxide Signaling

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Jessica L Fetterman ◽  
Nir Flint ◽  
Monica Holbrook ◽  
Erika A Linder ◽  
Brittany D Berk ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Endothelial Dysfunction ◽  
Vascular Function ◽  
Diabetic Patients ◽  
Autophagic Flux ◽  
Compensatory Response ◽  
Nitric Oxide Signaling ◽  
Patients With Diabetes ◽  
No Signaling

Diabetes is associated with oxidative stress and decreased nitric oxide bioactivity in the vasculature. Autophagy is a critical multistep pathway that eliminates damaged proteins and organelles from the cell. Emerging evidence suggests impaired autophagy in non-vascular tissues contributes to the pathogenesis of diabetes. We hypothesized that impaired autophagy contributes to endothelial dysfunction associated with diabetes in humans. We measured vascular function and autophagy markers in freshly isolated endothelial cells (ECs) from patients with diabetes and non-diabetic controls. Diabetes was associated with endothelial dysfunction characterized by lower brachial artery flow-mediated dilation and impaired activation of eNOS by insulin in ECs. ECs from diabetic patients had higher levels of p62 (Figure), a protein that accumulates with reduced autophagic flux. Measures of autophagy initiation including rapamycin stimulation, beclin 1 levels, and LC3 puncta were not different. Global activation of autophagy with spermidine reversed endothelial dysfunction in freshly isolated ECs from diabetic patients (Figure). In ECs from controls, inhibiting autophagy with bafilomycin impaired eNOS activation confirming that intact autophagy promotes NO signaling. Evidence from cultured endothelial cells in high glucose conditions suggested that lysosomal function is intact as measured by lysosomal number and acidification. Blocking the terminal step of autophagy with bafilomycin in ECs from diabetics led to a further accumulation of p62, suggesting intact but insufficient levels of autophagy. Lamp2a, which facilitates the merger of autophagosomes and lysosomes, was higher in diabetic cells, possibly reflecting a compensatory response to reduced flux. These findings provide evidence for inadequate autophagic flux in ECs from diabetic patients that contributes to impaired NO signaling and may be a target for therapy of diabetic vascular disease.

scholarly journals MicroRNA-133a impairs perfusion recovery after hindlimb ischemia in diabetic mice

2018 ◽  
Vol 38 (4) ◽  
Author(s):  
Lingdan Chen ◽  
Chunli Liu ◽  
Dejun Sun ◽  
Tao Wang ◽  
Li Zhao ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Endothelial Cells ◽  
Arterial Disease ◽  
Tube Formation ◽  
Cgmp Level ◽  
Diabetic Mice ◽  
Rt Pcr ◽  
Patients With Diabetes ◽  
Peripheral Arterial ◽  
Ischemic Muscle

Objective: Peripheral arterial disease (PAD) patients with diabetes mellitus suffer from impaired neovascularization after ischemia which results in poorer outcomes. MicroRNA (miR)-133a is excessively expressed in endothelial cells under diabetic conditions. Here, we test whether diabetes-induced miR-133a up-regulation is involved in the impaired capability of neovascularization in experimental PAD models. Methods and results: MiR-133a level was measured by quantitative RT-PCR and showed a higher expression level in the ischemic muscle from diabetic mice when compared with nondiabetic mice. Knockdown of miR-133a using antagomir improved perfusion recovery and angiogenesis in experimental PAD model with diabetes day 21 after HLI. On the other hand, overexpression of miR-133a impaired perfusion recovery. Ischemic muscle was harvested day 7 after experimental PAD for biochemical test, miR-133a antagonism resulted in reduced malondialdehyde, and it increased GTP cyclohydrolase 1 (GCH1), and cyclic guanine monophosphate (cGMP) levels. In cultured endothelial cells, miR-133a antagonism resulted in reduced reactive oxygen species level, and it increased tube formation, nitric oxide (NO), and cGMP level. Moreover, miR-133a antagonism-induced angiogenesis was abolished by GCH1 inhibitor. In contrary, miR-133a overexpression impairs angiogenesis and it reduces GCH1, NO, and cGMP levels in nondiabetic models. Conclusion: Diabetes mellitus-induced miR-133a up-regulation impairs angiogenesis in PAD by reducing NO synthesis in endothelial cells. MiR-133a antagonism improves postischemic angiogenesis.

scholarly journals Nitric oxide signaling in adipose triglyceride lipase-deficient microvascular endothelial cells

2012 ◽  
Vol 13 (Suppl 1) ◽  
pp. A22
Author(s):  
Marion Mussbacher ◽  
Sarah Winkler ◽  
Günter Hämmerle ◽  
Rudolf Zechner ◽  
Bernd Mayer ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Microvascular Endothelial Cells ◽  
Adipose Triglyceride Lipase ◽  
Nitric Oxide Signaling ◽  
Triglyceride Lipase ◽  
Microvascular Endothelial

Abstract 18673: JNK Inhibition Restores Endothelial Function in Type 2 Diabetes Mellitus

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Rosa Breton-Romero ◽  
Bihua Feng ◽  
Monika Holbrook ◽  
Melissa G Farb ◽  
Jessica L Fetterman ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Diabetes Mellitus ◽  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Endothelial Cells ◽  
Cardiovascular Diseases ◽  
Endothelial Dysfunction ◽  
Diabetic Patients ◽  
Jnk Activation

Introduction: Diabetes mellitus type 2 is an increasingly public health problem and it is a major cause in the development of cardiovascular diseases. Endothelial dysfunction is a key mechanism that contributes to the pathogenesis of cardiovascular diseases and is a well-known feature of clinical diabetes. Prior studies have demonstrated an impaired nitric oxide bioavailability and a reduced endothelium-dependent vasodilation under diabetic conditions and in animal models, JNK activity has been widely described to be involved in systemic insulin resistance. Hypothesis: Our study aimed to evaluate the involvement of JNK in endothelial dysfunction, studying its potential role in altered eNOS activation and NO synthesis in diabetic patients. Methods: We measured endothelial function and JNK activity in freshly isolated endothelial cells from diabetic patients (n=38) and nondiabetic controls (n=40). Results: ECs from diabetic patients displayed impaired eNOS activation and reduced NO release after insulin and A23187 stimulation, consistent with the presence of endothelial dysfunction. JNK activation was higher in diabetic (**P=0.003), and was associated with lower flow-mediated dilation (r=-0.53, *P=0.02). In endothelial cells from diabetic patients, treatment with JNK chemical inhibitor (SP600125) restored eNOS activation and insulin response (***P<0.001). Nitric oxide bioactivity after A23187 stimuli with diabetes was also recovered in endothelial cells from patients with diabetes. Conclusions: In summary, our data suggest that JNK activation contributes to vascular insulin resistance and endothelial dysfunction in patients with type 2 diabetes and may represent a target in novel therapeutic opportunities.

scholarly journals Shear stress stimulates nitric oxide signaling in pulmonary arterial endothelial cells via a reduction in catalase activity: role of protein kinase Cδ

2010 ◽  
Vol 298 (1) ◽  
pp. L105-L116 ◽  
Author(s):  
Sanjiv Kumar ◽  
Neetu Sud ◽  
Fabio V. Fonseca ◽  
Yali Hou ◽  
Stephen M. Black
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Catalase Activity ◽  
Serine Phosphorylation ◽  
Nitric Oxide Signaling ◽  
Enos Uncoupling ◽  
Pulmonary Arterial ◽  
Arterial Endothelial Cells

Previous studies have indicated that acute increases in shear stress can stimulate endothelial nitric oxide synthase (eNOS) activity through increased PI3 kinase/Akt signaling and phosphorylation of Ser1177. However, the mechanism by which shear stress activates this pathway has not been adequately resolved nor has the potential role of reactive oxygen species (ROS) been evaluated. Thus, the purpose of this study was to determine if shear-mediated increases in ROS play a role in stimulating Ser1177 phosphorylation and NO signaling in pulmonary arterial endothelial cells (PAEC) exposed to acute increases in shear stress. Our initial studies demonstrated that although shear stress did not increase superoxide levels in PAEC, there was an increase in H2O2 levels. The increases in H2O2 were associated with a decrease in catalase activity but not protein levels. In addition, we found that acute shear stress caused an increase in eNOS phosphorylation at Ser1177 phosphorylation and a decrease in phosphorylation at Thr495. We also found that the overexpression of catalase significantly attenuated the shear-mediated increases in H2O2, phospho-Ser1177 eNOS, and NO generation. Further investigation identified a decrease in PKCδ activity in response to shear stress, and the overexpression of PKCδ attenuated the shear-mediated decrease in Thr495 phosphorylation and the increase in NO generation, and this led to increased eNOS uncoupling. PKCδ overexpression also attenuated Ser1177 phosphorylation through a posttranslational increase in catalase activity, mediated via a serine phosphorylation event, reducing shear-mediated increases in H2O2. Together, our data indicate that shear stress decreases PKCδ activity, altering the phosphorylation pattern catalase, leading to decreased catalase activity and increased H2O2 signaling, and this in turn leads to increases in phosphorylation of eNOS at Ser1177 and NO generation.

Caveolin regulation of endothelial function

2003 ◽  
Vol 285 (6) ◽  
pp. L1179-L1183 ◽  
Author(s):  
Richard D. Minshall ◽  
William C. Sessa ◽  
Radu V. Stan ◽  
Richard G. W. Anderson ◽  
Asrar B. Malik
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Plasma Membrane ◽  
Endothelial Function ◽  
Cell Function ◽  
Signaling Molecules ◽  
Scaffolding Protein ◽  
Nitric Oxide Signaling ◽  
Caveolin 1 ◽  
Primary Means

Caveolae are the sites in the cell membrane responsible for concentrating an array of signaling molecules critical for cell function. Recent studies have begun to identify the functions of caveolin-1, the 22-kDa caveolar protein that oligomerizes and inserts into the cytoplasmic face of the plasma membrane. Caveolin-1 appears to regulate caveolar internalization by stabilizing caveolae at the plasma membrane rather than controlling the shape of the membrane invagination. Because caveolin-1 is a scaffolding protein, it has also been hypothesized to function as a “master regulator” of signaling molecules in caveolae. Deletion of the caveolin-1 gene in mice resulted in cardiac hypertrophy and lung fibrosis, indicating its importance in cardiac and lung development. In the endothelium, caveolin-1 regulates nitric oxide signaling by binding to and inhibiting endothelial nitric oxide synthase (eNOS). Increased cytosolic Ca2+or activation of the kinase Akt leads to eNOS activation and its dissociation from caveolin-1. Caveolae have also been proposed as the vesicle carriers responsible for transcellular transport (transcytosis) in endothelial cells. Transcytosis, the primary means of albumin transport across continuous endothelia, occurs by fission of caveolae from the membrane. This event is regulated by tyrosine phosphorylation of caveolin-1 and dynamin. As Ca2+influx channels and pumps are localized in caveolae, caveolin-1 is also an important determinant of Ca2+signaling in endothelial cells. Many of these findings were presented in San Diego, CA, at the 2003 Experimental Biology symposium “Caveolin Regulation of Endothelial Function” and are reviewed in this summary.

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