Half Of Adult Population Research Articles

Abstract 13610: Imbalance Between GCN5L1 Mediated CypD Acetylation and Sirt3 Deacetylase Promotes Mitochondrial Oxidative Stress, Endothelial Dysfunction and Hypertension

Nearly half of adult population has hypertension which is a main risk factor for cardiovascular disease. Mitochondrial dysfunction contributes to hypertension and targeting mitochondria can potentially improve treatment of hypertension. We found hyperacetylation of mitochondrial Cyclophilin D (CypD) in essential hypertension and proposed that CypD acetylation can promote endothelial dysfunction and hypertension. CypD acetylation is mediated by general control of amino acid synthesis 5 like 1 (GCN5L1) protein which is counteracted by deacetylase Sirt3. We tested potential role GCN5L1 and Sirt3 in endothelial dysfunction and hypertension. Western blot of aortic mitochondria showed an increased GCN5L1 level in hypertensive mice coupled with the reduction of Sirt3 deacetylase resulting in 250% increase in GCN5L1/Sirt3 ratio promoting CypD acetylation. We reported pathogenic role of lipid oxidation products isolevuglandins (isoLGs) and scavenging isoLGs by mitochondria-targeted mito2HOBA reduces mitochondrial acetylation. We tested if mitochondrial isoLGs contributes to acetylase/deacetylase imbalance driving CypD acetylation. Treatment with mito2HOBA improves Sirt3 expression and reduces GCN5L1 level resulting in normalization of GCN5L1/Sirt3 ratio and reduced CypD acetylation. To define the pathophysiological role of GCN5L1 in endothelial cells we tested if GCN5L1 depletion prevents cytokine-induced of mitochondrial oxidative stress. Indeed, treatment of human aortic endothelial cells with AngII+TNFα induces mitochondrial O 2 . -, however, GCN5L1 depletion using siRNA completely abrogated the cytokine-induced mitochondrial oxidative stress. To define the role GNC5L1 in pathogenesis of endothelial dysfunction we developed new tamoxifen-inducible endothelial specific GNC5L1 knockout mice (Ec GNC5L1KO ). Depletion of endothelial GCN5L1 reduces vascular mitochondrial O 2 . -, prevents inactivation of endothelial nitric oxide and preserves endothelial dependent relaxation in angiotensin II-infused Ec GNC5L1KO mice compared with wild-type littermates. These data support the pathogenic role of GNC5L1 in CypD acetylation and endothelial dysfunction and targeting GNC5L1 can be beneficial in cardiovascular disease.

Abstract P237: Mitochondrial GCN5L1 Promotes CypD Acetylation, Oxidative Stress, Endothelial Dysfunction And Hypertension

Nearly half of adult population has hypertension which is a main risk factor for cardiovascular disease. Mitochondrial dysfunction contributes to hypertension and targeting mitochondria can potentially improve treatment of hypertension. We found hyperacetylation of mitochondrial Cyclophilin D (CypD) in essential hypertension and proposed that CypD acetylation can promote endothelial dysfunction and hypertension. CypD acetylation can be regulated by general control of amino acid synthesis 5 like 1 (GCN5L1) protein, therefore, we GCN5L1 can potentially promote endothelial dysfunction and hypertension. Western blot of aortic mitochondria showed an increased GCN5L1 level in hypertensive mice which was coupled with the reduction of Sirt3 deacetylase level resulting in 250% increase in GCN5L1/Sirt3 ratio promoting CypD acetylation. We reported pathogenic role of mitochondrial lipid oxidation products isolevuglandins (isoLGs) and scavenging of isoLGs with mitochondria-targeted mito2HOBA reduces mitochondrial acetylation. We tested if mitochondrial isoLGs contributes to acetylase/deacetylase imbalance driving CypD acetylation. It was found that mito2HOBA supplementation improves Sirt3 expression and reduces GCN5L1 level leading to normalization of GCN5L1/Sirt3 ratio and reduced CypD acetylation. To define the pathophysiological role of GCN5L1 in endothelial cells we tested if GCN5L1 depletion prevents cytokine-induced of mitochondrial oxidative stress. Indeed, treatment of human aortic endothelial cells with AngII+TNFα induces mitochondrial O 2 . -, however, GCN5L1 depletion using siRNA completely abrogated the cytokine-induced mitochondrial oxidative stress. To define the role GNC5L1 in pathogenesis of endothelial dysfunction we have developed new tamoxifen-inducible endothelial specific GNC5L1 knockout mice (Ec GNC5L1KO ). It was found that depletion of endothelial GCN5L1 reduces vascular production of mitochondrial O 2 . -, prevents inactivation of endothelial nitric oxide and preserves endothelial dependent relaxation in angiotensin II-infused Ec GNC5L1KO mice compared with wild-type littermates. These data support the pathogenic role of GNC5L1 in CypD acetylation and development of endothelial dysfunction.

VEGF-C Is a Thyroid Marker of Malignancy Superior to VEGF-A in the Differential Diagnostics of Thyroid Lesions.

IntroductionThyroid nodular goiter is one of the most common medical conditions affecting even over a half of adult population. The risk of malignancy is rather small but noticeable–estimated by numerous studies to be about 3–10%. The definite differentiation between benign and malignant ones is a vital issue in endocrine practice. The aim of the current study was to assess the expression of vascular endothelial growth factor A (VEGF-A) and VEGF-C on the mRNA level in FNAB washouts in case of benign and malignant thyroid nodules and to evaluate the diagnostic value of these markers of malignancy.Materials and MethodsPatients undergoing fine-needle aspiration biopsy (FNAB) in our department between January 2013 and May 2014 were included. In case of all patients who gave the written consent, after ultrasonography (US) and fine-needle aspiration biopsy (FNAB) performed as routine medical procedure the needle was flushed with RNA Later solution, the washouts were frozen in -80 Celsius degrees. Expression of VEGF-A and VEGF-C and GADPH (reference gene) was assessed in washouts on the mRNA level using the real-time PCR technique. Probes of patients who underwent subsequent thyroidectomy and were diagnosed with differentiated thyroid cancer (DTC; proved by post-surgical histopathology) were analyzed. Similar number of patients with benign cytology were randomly selected to be a control group.ResultsThirty one DTCs and 28 benign thyroid lesions were analyzed. Expression of VEGF-A was insignificantly higher in patients with DTCs (p = 0.13). Expression of VEGF-C was significantly higher in patients with DTC. The relative expression of VEGF-C (in comparison with GAPDH) was 0.0049 for DTCs and 0.00070 for benign lesions, medians – 0.0036 and 0.000024 respectively (p<0.0001).ConclusionsMeasurement of expression VEGF-C on the mRNA level in washouts from FNAB is more useful than more commonly investigated VEGF-A. Measurement of VEGF-C in FNAB washouts do not allow for fully reliable differentiation of benign and malignant thyroid nodules and should be interpreted carefully. Further studies on larger groups are indicated. However, measurement of VEGF-C on mRNA level can bring important information without exposing patient for additional risk and invasive procedures.