The Calcineurin Antagonist, RCAN1-4 is Induced by Exhaustive Exercise in Rat Skeletal Muscle

International audienceThe aim of this work was to study the regulation of the calcineurin antagonist regulator of calcineurin 1 (RCAN1) in rat skeletal muscles after exhaustive physical exercise, which is a physiological modulator of oxidative stress. Three skeletal muscles, namely extensor digitorum longus (EDL), gastrocnemius, and soleus, were investigated. Exhaustive exercise increased RCAN1-4 protein levels in EDL and gastrocnemius, but not in soleus. Protein oxidation as an index of oxidative stress was increased in EDL and gastrocnemius, but remained unchanged in soleus. However, lipid peroxidation was increased in all three muscles. CuZnSOD and catalase protein levels were increased at 3 h postexercise in soleus, whereas they remained unchanged in EDL and gastrocnemius. Calcineurin enzymatic activity declined in EDL and gastrocnemius but not in soleus, and its protein expression was decreased in all three muscles. The level of PGC1-α protein remained unchanged, whereas the protein expression of the transcription factor NFATc4 was decreased in all three muscles. Adiponectin expression was increased in all three muscles. RCAN1-4 expression in EDL and gastrocnemius muscles was augmented by the oxidative stress generated from exhaustive exercise. We propose that increased RCAN1-4 expression and the signal transduction pathways it regulates represent important components of the physiological adaptation to exercise-induced oxidative stress

Hemocyte-specific responses to the peroxidizing herbicide fomesafen in the pond snail Lymnaea stagnalis (Gastropoda, Pulmonata).

Responses of circulating hemocytes were studied in Lymnaea stagnalis exposed to 10, 30, 90, and 270 mg/L fomesafen for 24 and 504 h. Flow cytometry was used to quantify fomesafen-induced production of reactive oxygen species (ROS), phagocytic activity on Escherichia coli, and oxidative burst when hemocytes were challenged by E. coli or phorbol 12-myristate-13-acetate (PMA). Lysosomal membrane damage was assessed, using the neutral-red retention time (NRRT) assay. Exposure to fomesafen for 24 h resulted in increase in ROS levels and decreases in phagocytosis and the oxidative burst in PMA-stimulated hemocytes. After 504 h, intracellular levels of ROS returned to normal, but phagocytosis of E. coli was still inhibited and the associated oxidative burst significantly reduced. After both durations of exposure, decreases of NRRT indicated that lysosome membrane fragility increased with fomesafen concentration. Potential implications for the health and survival of the snails and consequences on populations are discussed

Inhibition of hemocyte-mediated immune function in Lymnaea stagnalis exposed to the herbicide ether herbicide fomesafen

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Inhibition of hemocyte-mediated immune function in Lymnaea stagnalis exposed to the herbicide ether herbicide fomesafen

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Prostate cancer and physical activity: Adaptive response to oxidative stress.

International audienceAbstract Prostate cancer is the most common form of cancer affecting men in the Western world. Its relative incidence increases exponentially with age and a steady increase is observed with extended life span. A sedentary lifestyle represents an important risk factor and a decrease in prostate cancer prevalence is associated with exercise. However, the molecular mechanisms involved in this process remain unknown. We hypothesize that reactive oxygen species generated by physical exercise are a key regulatory factor in prostate cancer prevention. Aging is correlated with increased oxidative stress (OS), which in turn provides a favorable environment for tumorigenesis. Running training is known to enhance the antioxidant defense system, reducing oxidative stress. In this context, the decrease in OS induced by exercise may delay the development of prostate cancer. This review focuses on oxidative stress-based mechanisms leading to prostate cancer sensitization to exercise, which could have some impact on the development of novel cancer therapeutic strategies

Cell redox environment and antioxidant enzyme activities in the pond snail Lymnaea stagnalis exposed to diquat and fomesafen with and without Agral90

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Effects of fomesafen and fomesafen-Agral 90 mixture on cell redox environment in the pond snail Lymnaea stagnalis.

Effects of fomesafen and fomesafen-Agral 90 mixture on cell redox environment in the pond snail Lymnaea stagnalis.. 4. World Congress of SETA

Antioxidant supplementation accelerates cachexia development by promoting tumor growth in C26 tumor-bearing mice

International audienceMore than 50% of patients with advanced stages of colon cancer suffer from progressive loss of skeletal muscle, called cachexia, resulting in reduced quality of life and shortened survival. It is becoming evident that reactive oxygen species (ROS) regulate pathways controlling skeletal muscle atrophy. Herein we tested the hypothesis that antioxidant supplementation could prevent skeletal muscle atrophy in a model of cachectic Colon 26 (C26) tumor-bearing mice. Seven-week-old BALB/c mice were subcutaneously inoculated with colon 26 (C26) cancer cells or PBS. Then C26-mice were daily gavaged during 22 days either with PBS (vehicle) or an antioxidant cocktail whose composition is close to that of commercial dietary antioxidant supplements (rich in catechins, quercetin and vitamin C). We found that antioxidants enhanced weight loss and caused premature death of mice. Antioxidants supplementation failed to prevent (i) the increase in plasma TNF-α levels and systemic oxidative damage, (ii) skeletal muscle atrophy and (iii) activation of the ubiquitin-proteasome system (MuRF-1, MAFbx and polyubiquitinated proteins). Accordingly, immunohistological staining for Ki-67 and the expression of cell cycle inhibitors demonstrated that tumor of supplemented mice developed faster with a concomitant decrease in oxidative damage. Previous studies have shown that the use of catechins and quercetin separately can improve the musculoskeletal function in cachectic animals. However, our results indicate that the combination of these antioxidants reduced survival and enhanced cachexia in C26-mice

Effects of fomesafen and fomesafen-agral R90 mixture on cell redox environment in the pond snail Lymnaea stagnalis.

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The adjuvant Agral 90 as a modulator of hemocyte-mediated immune responses induced by diquat and fomesafen in Lymnaea stagnalis.

The adjuvant Agral 90 as a modulator of hemocyte-mediated immune responses induced by diquat and fomesafen in Lymnaea stagnalis.. 15. Europe Annual Meeting of SETA