Alexandre Dermargos

Melatonin decreases muscular oxidative stress and inflammation induced by strenuous exercise and stimulates growth factor synthesis.

Strenuous exercise is detrimental to athletes because of the overproduction of reactive oxygen species. Melatonin, a classic antioxidant, has been shown to exhibit beneficial effects regarding intense exercise and tissue repair. In this study, we evaluated the onset and resolution of inflammation in melatonin‐treated and nontreated rats subjected to a strenuous exercise session. We also analyzed the formation of thiobarbituric acid reactive substances (TBARS) and the activities of catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD). Control and treated rats were subjected to exhaustive exercise after a period of 10 days of melatonin treatment (20 mg/dL). Plasma and muscle levels of tumor necrosis factor‐alpha (TNF‐α), interleukin 1 beta (IL‐1β), interleukin 6 (IL‐6), cytokine‐induced neutrophil chemoattractant‐2‐alpha/beta (CINC‐2α/β), l‐selectin, macrophage inflammatory protein‐3‐alpha (MIP‐3α), and vascular endothelial growth factor (VEGF) were measured prior to, immediately after, and 2 hr after exercise. Our data revealed decreases in the muscle concentrations of IL‐1β (35%), TNF‐α (13%), IL‐6 (48%), and TBARS (40%) in the melatonin‐treated group compared with the control group. We also observed decreases in the plasma concentrations of IL‐1β (17%) in the melatonin‐treated group. VEGF‐α concentrations and SOD activity increased by 179% and 22%, respectively, in the melatonin‐treated group compared with the control group. We concluded that muscle inflammation and oxidative stress resulting from exhaustive exercise were less severe in the muscles of melatonin‐treated animals than in the muscles of control animals. Thus, melatonin treatment may reverse exercise‐induced skeletal muscle inflammation and stimulate growth factor synthesis.

Oleic, Linoleic and Linolenic Acids Increase ROS Production by Fibroblasts via NADPH Oxidase Activation

The effect of oleic, linoleic and γ-linolenic acids on ROS production by 3T3 Swiss and Rat 1 fibroblasts was investigated. Using lucigenin-amplified chemiluminescence, a dose-dependent increase in extracellular superoxide levels was observed during the treatment of fibroblasts with oleic, linoleic and γ-linolenic acids. ROS production was dependent on the addition of β-NADH or NADPH to the medium. Diphenyleneiodonium inhibited the effect of oleic, linoleic and γ-linolenic acids on fibroblast superoxide release by 79%, 92% and 82%, respectively. Increased levels of p47phox phosphorylation due to fatty acid treatment were detected by Western blotting analyses of fibroblast proteins. Increased p47phox mRNA expression was observed using real-time PCR. The rank order for the fatty acid stimulation of the fibroblast oxidative burst was as follows: γ-linolenic > linoleic > oleic. In conclusion, oleic, linoleic and γ-linolenic acids stimulated ROS production via activation of the NADPH oxidase enzyme complex in fibroblasts.

Serum amyloid A induces reactive oxygen species (ROS) production and proliferation of fibroblast

Serum amyloid A (SAA) levels are elevated highly in acute phase response and elevated slightly and persistently in chronic diseases such as rheumatoid arthritis and diabetes. Given that fibroblasts exert profound effects on progression of inflammatory chronic diseases, the aim of this study was to investigate the response of fibroblasts to SAA. A dose‐dependent increase in O2‐ levels was observed by treatment of fibroblasts with SAA (r = 0·99 and P ≤ 0·001). In addition, the expression of p47‐phox was up‐regulated by SAA (P < 0·001) and diphenyliodonium (DPI), a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor, reduced the release of O2‐ by 50%. Also, SAA raised fibroblast proliferation (P < 0·001) and this effect was completely abolished by the addition of anti‐oxidants (P < 0·001). These findings support the notion that, in chronic inflammatory sites, SAA activated fibroblast proliferation and ROS production.

Fibroblast Growth Factor 2 Restrains Ras-Driven Proliferation of Malignant Cells by Triggering RhoA-Mediated Senescence

Fibroblast growth factor 2 (FGF2) is considered to be a bona fide oncogenic factor, although results from our group and others call this into question. Here, we report that exogenous recombinant FGF2 irreversibly inhibits proliferation by inducing senescence in Ras-dependent malignant mouse cells, but not in immortalized nontumorigenic cell lines. We report the following findings in K-Ras-dependent malignant Y1 adrenocortical cells and H-Ras V12-transformed BALB-3T3 fibroblasts: (a) FGF2 inhibits clonal growth and tumor onset in nude and immunocompetent BALB/c mice, (b) FGF2 irreversibly blocks the cell cycle, and (c) FGF2 induces the senescence-associated beta-galactosidase with no accompanying signs of apoptosis or necrosis. The tyrosine kinase inhibitor PD173074 completely protected malignant cells from FGF2. In Y1 adrenal cells, reducing the constitutively high levels of K-Ras-GTP using the dominant-negative RasN17 mutant made cells resistant to FGF2 cytotoxicity. In addition, transfection of the dominant-negative RhoA-N19 into either Y1 or 3T3-B61 malignant cell lines yielded stable clonal transfectants that were unable to activate RhoA and were resistant to the FGF2 stress response. We conclude that in Ras-dependent malignant cells, FGF2 interacts with its cognate receptors to trigger a senescence-like process involving RhoA-GTP. Surprisingly, attempts to select FGF2-resistant cells from the Y1 and 3T3-B61 cell lines yielded only rare clones that (a) had lost the overexpressed ras oncogene, (b) were dependent on FGF2 for proliferation, and (c) were poorly tumorigenic. Thus, FGF2 exerted a strong negative selection that Ras-dependent malignant cells could rarely overcome.

GenFlow: Generic flow for integration, management and analysis of molecular biology data

A large number of DNA sequencing projects all over the world have yielded a fantastic amount of data, whose analysis is, currently, a big challenge for computational biology. The limiting step in this task is the integration of large volumes of data stored in highly heterogeneous repositories of genomic and cDNA sequences, as well as gene expression results. Solving this problem requires automated analytical tools to optimize operations and efficiently generate knowledge. This paper presents an information flow model , called GenFlow, that can tackle this analytical task.

Chronic inflammation and neutrophil activation as possible causes of joint diseases in ballet dancers.

Herein, we investigated the effects of a ballet class on the kinetic profiles of creatine kinase (CK) and lactate dehydrogenase (LDH) activities, cytokines, complement component 3 (C3), and the concentrations of immunoglobulin (Ig), IgA and IgM, in ballerinas. We also verified neutrophil death and ROS release. Blood samples were taken from 13 dancers before, immediately after, and 18 hours after a ballet class. The ballet class increased the plasma activities of CK-total (2.0-fold) immediately after class, while the activities of CK-cardiac muscle (1.0-fold) and LDH (3.0-fold) were observed to increase 18 hours after the class. Levels of the TNF-α, IL-1β, IgG, and IgA were not affected under the study conditions. The exercise was found to induce neutrophil apoptosis (6.0-fold) 18 hours after the ballet class. Additionally, immediately after the ballet class, the neutrophils from the ballerinas were found to be less responsive to PMA stimulus. Conclusion. Ballet class was found to result in inflammation in dancers. The inflammation caused by the ballet class remained for 18 hours after the exercise. These findings are important in preventing the development of chronic lesions that are commonly observed in dancers, such as those with arthritis and synovitis.

Neutrophil Migration and Adhesion Molecule Expression after Acute High-Intensity Street Dance Exercise

The physical demands of street dancing may result in inflammation and changes in leukocyte numbers/function, impairing the health of dancers. Herein, we investigated the effect of street dancing on inflammation, adhesion molecules, and neutrophil function. Fifteen amateur dancers (mean ± SE: age 22.4 ± 1.08 years, BMI 24.8 ± 0.69 kg/m2, and body fat 12.3 ± 1.52%) participated in a single high-intensity street dance class. Blood samples were taken before and after the class. The dance class had no effect on the plasma concentration of CRP, TNF-α, IL-6, IL-10, and IL-8; however, we noted an increase in levels of IL-1β (4.06%) and sL-selectin (17.67%). The dance class resulted in a 12.36% increase in neutrophil counts, while neutrophil CD62L expression and migration were reduced (25.27% and 78.92%, resp.). After the dance class, neutrophil production of IL-8 and TNF-α increased, respectively, by 59.75% and 49.23%, in the control condition, and 43.55% and 32.22%, after LPS stimulation. A single bout of street dancing induced inflammation and reduced neutrophil migration and adhesion molecule expression. These findings may contribute to a better understanding of the susceptibility to infection after acute dance exercise.

Topical anti-inflammatory activity of palmitoleic acid improves wound healing

This study investigated the effects of palmitoleic acid on different phases of the healing process. Macroscopic analyses were performed on wounds in rats with or without palmitoleic acid treatment, and the results showed that palmitoleic acid directly hastened wound closure. The topical treatment of wounds with palmitoleic acid resulted in smaller wounds than those observed in the control group. The anti-inflammatory activity of palmitoleic acid may be responsible for healing, especially in the stages of granulation tissue formation and remodelling. Palmitoleic acid modified TNF-α, IL-1β, IL-6, CINC-2α/β, MIP-3α and VEGF-α profiles at the wound site 24, 48, 120, 216 and 288 hours post-wounding. Assays assessing neutrophil migration and exudate formation in sterile inflammatory air pouches revealed that palmitoleic acid had potent anti-inflammatory activity, inhibiting the LPS-induced release of TNF-α (73.14%, p≤0.05), IL-1β (66.19%, p≤0.001), IL-6 (75.19%, p≤0.001), MIP-3α (70.38%, p≤0.05), and l-selectin (16%, p≤0.05). Palmitoleic acid also inhibited LPS-stimulated neutrophil migration. We concluded that palmitoleic acid accelerates wound healing via an anti-inflammatory effect.

The Effect of a Competitive Futsal Match on T Lymphocyte Surface Receptor Signaling and Functions

In this study, the lymphocyte activation status (surface expression of CD95, CD28, CD25, and CTLA-4), lymphocyte number, lymphocyte subpopulations, lymphocyte necrosis and/or apoptosis, and lymphocyte release of reactive oxygen species (ROS) were investigated in blood samples from 16 futsal athletes before and immediately following a competitive match. Lymphocytes were isolated from the blood samples, and the cellular parameters were assessed by flow cytometry. The futsal match induced lymphocytosis and lymphocyte apoptosis, as indicated by phosphatidylserine externalization, CD95 expression, and DNA fragmentation. Additionally, the competitive match induced the necrotic death of lymphocytes. No differences in the percentage of CD4+ and CD8+ T cells or in the T-helper/suppressor profile between before and immediately after the match were observed. Additionally, after the futsal match, the CD95 and CD28 expression levels were decreased, and the lymphocytes spontaneously released higher levels of ROS. Regardless of the origin, the situation-specific knowledge of lymphocyte behavior obtained herein may facilitate the design of strategies to control the processes that result in infection and tissue injury and that subsequently decrease athletic performance.