The AtCRK5 Protein Kinase Is Required to Maintain the ROS NO Balance Affecting the PIN2-Mediated Root Gravitropic Response in Arabidopsis

The Arabidopsis AtCRK5 protein kinase is involved in the establishment of the proper auxin gradient in many developmental processes. Among others, the Atcrk5-1 mutant was reported to exhibit a delayed gravitropic response via compromised PIN2-mediated auxin transport at the root tip. Here, we report that this phenotype correlates with lower superoxide anion (O2•−) and hydrogen peroxide (H2O2) levels but a higher nitric oxide (NO) content in the mutant root tips in comparison to the wild type (AtCol-0). The oxidative stress inducer paraquat (PQ) triggering formation of O2•− (and consequently, H2O2) was able to rescue the gravitropic response of Atcrk5-1 roots. The direct application of H2O2 had the same effect. Under gravistimulation, correct auxin distribution was restored (at least partially) by PQ or H2O2 treatment in the mutant root tips. In agreement, the redistribution of the PIN2 auxin efflux carrier was similar in the gravistimulated PQ-treated mutant and untreated wild type roots. It was also found that PQ-treatment decreased the endogenous NO level at the root tip to normal levels. Furthermore, the mutant phenotype could be reverted by direct manipulation of the endogenous NO level using an NO scavenger (cPTIO). The potential involvement of AtCRK5 protein kinase in the control of auxin-ROS-NO-PIN2-auxin regulatory loop is discussed.

Intracellular Oxidative Stress Levels are Significantly Associated with the Green Autofluorescence Intensity of Buthionine Sulfoximine-Treated B16-F10 Cells

Since oxidative stress is a critical common pathological factor of numerous diseases, it is critical to find biomarkers for non-invasive evaluations of the levels of oxidative stress in the body. Our previous studies have indicated that epidermal green autofluorescence (AF) is a novel biomarker of this type: The oxidative stress inducer buthionine sulfoximine (BSO) can dose-dependently increase the epidermal green AF of mice, with BSO doses being significantly associated with the AF intensity. However, it is necessary to use skin cell cultures to investigate the mechanisms underlying the relationships between BSO and the green AF intensity. In our current study we found that BSO concentration-dependently increased the green AF intensity of B16-F10 cells a skin cell line, with BSO concentrations being significantly associated with the AF intensity. BSO also concentration-dependently increased the intracellular DCF signals an index of ROS levels. The green AF intensity of the cells was also significantly associated with the intracellular ROS levels. Moreover, we found that the green AF intensity was significantly associated with the cell death induced by BSO. Collectively, our study has provided first evidence indicating that the green AF intensity of skin cells is significantly associated with both intracellular ROS levels and cell death of the skin cells exposed to oxidative stress, which has indicated that green AF is a novel biomarker for both oxidative stress and cell death.

Synthesis of Novel Selenocyanates and Evaluation of Their Effect in Cultured Mouse Neurons Submitted to Oxidative Stress

Herein, we report the synthesis of novel selenocyanates and assessment of their effect on the oxidative challenge elicited by hydrogen peroxide (H2O2) in cultured mouse neurons. First, α-methylene-β-hydroxy esters were prepared as precursors of allylic bromides. A reaction involving the generated bromides and sodium selenocyanate was conducted to produce the desired selenocyanates (3a-f). We next prepared cultures of neurons from 7-day-old mice (n=36). H2O2 (10-5 M) was added into the culture flasks as an oxidative stress inducer, alone or combined with one of each designed compounds. (PhSe)2 was used as a positive control. It was carried out assessment of lipid (thiobarbituric acid reactive species, 4-hydroxy-2′-nonenal, 8-isoprostane), DNA (8-hydroxy-2′-deoxyguanosine), and protein (carbonyl) modification parameters. Finally, catalase and superoxide dismutase activities were also evaluated. Among the compounds, 3b, 3d, and 3f exhibited the most pronounced pattern of antioxidant activity, similar to (PhSe)2. These novel aromatic selenocyanates could be promising to be tried in most sophisticated in vitro studies or even at the preclinical level.

Synthesis of Novel Selenocyanates and Evaluation of Their Effect in Cultured Mouse Neurons Submitted to Oxidative Stress

<p>Herein we report the synthesis of novel selenocyanates and assessment of their effect on the oxidative challenge elicited by hydrogen peroxide (H₂O₂) in cultured mouse neurons. First, <i>α</i>-methylene-<i>β</i>-hydroxy esters were prepared as precursors of allylic bromides. A reaction involving the generated bromides and sodium selenocyanate was conducted to produce the desired selenocyanates (<b>3a-f</b>). We next prepared cultures of neurons from 7-day-old-mice (<i>n </i>= 36). H₂O₂ (10^⁻5 M) was added into the culture flasks as an oxidative stress inducer, alone or combined with one of each designed compounds. PhSe)₂ was used as positive control. It was carried out assessment of lipid (thiobarbituric acid reactive species, 4-hydroxy-2’-nonenal, 8-isoprostane), DNA (8-hydroxy-2’-deoxyguanosine) and protein (carbonyl) modification parameters. Finally, catalase and superoxide dismutase activities were also evaluated. Among the compounds, <b>3b</b>, <b>3d</b> and <b>3f</b> exhibited the most pronounced pattern of antioxidant activity, similar to (PhSe)₂. These novel aromatic selenocyanates could be promising to be tried in most sophisticated <i>in vitro </i>studies or even at preclinical level.</p>

Synthesis of Novel Selenocyanates and Evaluation of Their Effect in Cultured Mouse Neurons Submitted to Oxidative Stress

<p>Herein we report the synthesis of novel selenocyanates and assessment of their effect on the oxidative challenge elicited by hydrogen peroxide (H₂O₂) in cultured mouse neurons. First, <i>α</i>-methylene-<i>β</i>-hydroxy esters were prepared as precursors of allylic bromides. A reaction involving the generated bromides and sodium selenocyanate was conducted to produce the desired selenocyanates (<b>3a-f</b>). We next prepared cultures of neurons from 7-day-old-mice (<i>n </i>= 36). H₂O₂ (10^⁻5 M) was added into the culture flasks as an oxidative stress inducer, alone or combined with one of each designed compounds. PhSe)₂ was used as positive control. It was carried out assessment of lipid (thiobarbituric acid reactive species, 4-hydroxy-2’-nonenal, 8-isoprostane), DNA (8-hydroxy-2’-deoxyguanosine) and protein (carbonyl) modification parameters. Finally, catalase and superoxide dismutase activities were also evaluated. Among the compounds, <b>3b</b>, <b>3d</b> and <b>3f</b> exhibited the most pronounced pattern of antioxidant activity, similar to (PhSe)₂. These novel aromatic selenocyanates could be promising to be tried in most sophisticated <i>in vitro </i>studies or even at preclinical level.</p>