Oxidative DNA damage in female patients with diabetes mellitus type 2.

Diabetes mellitus type 2 is very often associated with increased levels of reactive oxygen species. Previous studies also showed higher DNA damage in patients with diabetes mellitus type 2 compared to healthy controls (Tatsch et al., 2012; Blasiak et al., 2004). However, blood glucose concentration and level of glycated hemoglobin (HbA1c) can vary widely between diabetic patients and depends on country specific threshold levels. Therefore our aim was to analyze DNA damage in patients with lower glycated hemoglobin (HbA1c7.5%; n=72). In total 146 patients of the local diabetes outpatient clinic in Vienna were enrolled (age: 67.5±9,9years; BMI: 35.0±7.6kg/m²; diabetes duration: 14.4±8.0years).The Comet assay was performed in PBMCs (strand breaks, resistance to H2O2, FPG-sensitive sites) and whole blood (strand breaks, FPG-sensitive sites). No differences in DNA damage were found between the two groups of low vs. high HbA1c. In addition, neither diabetes duration nor medication (Insulin vs. oral antidiabetics) had an influence on DNA damage. Therefore we can conclude that female patients with diabetes mellitus type 2 in Austria are under optimal treatment to control blood sugar and other metabolic parameter, that no differences in DNA damage could be observed

Aryl hydrocarbon receptor signaling regulates NF-κB RelB activation during dendritic-cell differentiation.

How the aryl hydrocarbon receptor (AhR) regulates dendritic-cell (DC) differentiation is unknown. We show that activation of AhR by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) caused enhanced differentiation from immature DCs (IDCs) to mature DCs (MDCs) in the bone-marrow-derived DCs (BMDC) from B6 wild-type mice but not in the BMDCs from AhR-null mice as indicated by the expression of CD11c and class II major histocompatibility complex (MHC). Enhanced maturation of BMDCs was associated with elevated levels of CD86 and an increased AhR-dependent nuclear accumulation of nuclear factor-kappa-light-chain enhancer of activated B cell (NF-κB) member RelB in BMDCs. The expression of interleukin (IL) 10 and chemokine DC-CK1 was suppressed, whereas that of CXCL2, CXCL3 and IL-22 was significantly increased in AhR-activated BMDCs. Furthermore, TCDD induced expression of the regulatory enzymes indoleamine 2,3-dioxygenase (IDO1) and indoleamine 2,3-dioxygenase-like 1 (IDO2). Increased expression of IDO2 was associated with coexpression of the cell-surface marker CCR6. Interestingly, mRNA expression of the chemokine receptor CCR6 was drastically decreased in AhR-null IDCs and MDCs. Overall, these data demonstrate that AhR modifies the maturation of BMDCs associated with the induction of the regulatory enzyme IDO and altered expression of cytokine, chemokines and DC-specific surface markers and receptors

Aryl hydrocarbon receptor signaling regulates NF‐κB RelB activation during dendritic‐cell differentiation

How the aryl hydrocarbon receptor (AhR) regulates dendritic-cell (DC) differentiation is unknown. We show that activation of AhR by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) caused enhanced differentiation from immature DCs (IDCs) to mature DCs (MDCs) in the bone-marrow-derived DCs (BMDC) from B6 wild-type mice but not in the BMDCs from AhR-null mice as indicated by the expression of CD11c and class II major histocompatibility complex (MHC). Enhanced maturation of BMDCs was associated with elevated levels of CD86 and an increased AhR-dependent nuclear accumulation of nuclear factor-kappa-light-chain enhancer of activated B cell (NF-κB) member RelB in BMDCs. The expression of interleukin (IL) 10 and chemokine DC-CK1 was suppressed, whereas that of CXCL2, CXCL3 and IL-22 was significantly increased in AhR-activated BMDCs. Furthermore, TCDD induced expression of the regulatory enzymes indoleamine 2,3-dioxygenase (IDO1) and indoleamine 2,3-dioxygenase-like 1 (IDO2). Increased expression of IDO2 was associated with coexpression of the cell-surface marker CCR6. Interestingly, mRNA expression of the chemokine receptor CCR6 was drastically decreased in AhR-null IDCs and MDCs. Overall, these data demonstrate that AhR modifies the maturation of BMDCs associated with the induction of the regulatory enzyme IDO and altered expression of cytokine, chemokines and DC-specific surface markers and receptors

Oxidative stress, DNA Damage and DNA repair in female patients with diabetes mellitus type 2

Diabetes mellitus type 2 (T2DM) is associated with oxidative stress which in turn can lead to DNA damage. The aim of the present study was to analyze oxidative stress, DNA damage and DNA repair in regard to hyperglycemic state and diabetes duration.Female T2DM patients (n = 146) were enrolled in the MIKRODIAB study and allocated in two groups regarding their glycated hemoglobin (HbA1c) level (HbA1c≤7.5%, n = 74; HbA1c>7.5%, n = 72). In addition, tertiles according to diabetes duration (DD) were created (DDI = 6.94±3.1 y, n = 49; DDII = 13.35±1.1 y, n = 48; DDIII = 22.90±7.3 y, n = 49). Oxidative stress parameters, including ferric reducing ability potential, malondialdehyde, oxidized and reduced glutathione, reduced thiols, oxidized LDL and F2-Isoprostane as well as the activity of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase were measured. Damage to DNA was analyzed in peripheral blood mononuclear cells and whole blood with single cell gel electrophoresis. DNA base excision repair capacity was tested with the modified comet repair assay. Additionally, mRNA expressions of nine genes related to base excision repair were analyzed in a subset of 46 matched individuals.No significant differences in oxidative stress parameters, antioxidant enzyme activities, damage to DNA and base excision repair capacity, neither between a HbA1c cut off />7.5%, nor between diabetes duration was found. A significant up-regulation in mRNA expression was found for APEX1, LIG3 and XRCC1 in patients with >7.5% HbA1c. Additionally, we observed higher total cholesterol, LDL-cholesterol, LDL/HDL-cholesterol, triglycerides, Framingham risk score, systolic blood pressure, BMI and lower HDL-cholesterol in the hyperglycemic group.BMI, blood pressure and blood lipid status were worse in hyperglycemic individuals. However, no major disparities regarding oxidative stress, damage to DNA and DNA repair were present which might be due to good medical treatment with regular health checks in T2DM patients in Austria

Fold changes of mRNA expression of DNA BER enzymes.

<p>T2DM patients with HbA1c>7.5% (n = 23) in relation to matched T2DM patients with HbA1c<7.5% (n = 23). For each pair, results were normalized to the HbA1c<7.5% expression. Matching was according to age, medication and smoking history. Significance was assumed at p<0.05 and tested with one-sample t-test against “1” or Wilcoxon test against “1” if normal distribution was not assumed. (a) Fold-changes presented as bar plots showing mean and standard deviation. (b) Distribution of fold changes. Each point represents a matching pair (n = 23).</p

Primer sequences for gene expression analyses.

<p>Primer sequences for gene expression analyses.</p

Differences between HbA1c groups in DNA damage, BER capacity, oxidative stress parameters and antioxidant enzyme activities.

<p>Differences between HbA1c groups in DNA damage, BER capacity, oxidative stress parameters and antioxidant enzyme activities.</p