Oxidative Stress and Friedreich’s Ataxia

Friedreich’s Ataxia (FRDA) is a neurodegenerative disorder caused by a deficiency of the protein frataxin and characterized by oxidative stress. The first aim of my research project was to analyze the effects of tocotrienol in FRDA patients. Patients received for 2 months a low dose of tocotrienol. A number of biochemical parameters related to oxidative stress were studied. We consistently showed that taking for 2 months a low dose of tocotrienol led to the decrease of oxidative stress indexes in FRDA patients. Also, this study provides a suitable model to investigate the efficacy of natural compounds to counteract the oxidative stress in FRDA. Furthermore, we investigated whether the tocotrienol was able to modulate the expression of the frataxin isoforms (FXN-1, FXN -2, FXN-3) in FRDA patients. We demonstrated that tocotrienol leads to a specific and significant increase of FXN-3 expression. As no structural and functional details were available for FNX-2 and FXN-3, 3D-models were built. FXN-1, the canonical isoform, was then docked on the human iron-sulphur complex and functional interactions were computed; when FXN-1 was replaced by FXN-2 or FNX-3, we found that the interactions were maintained, thus suggesting a possible biological role for both isoforms. The second aim of my research project was to investigate the role of a single nucleotide polymorphism (SNP) in the protein Sirtuin 6 in FRDA patients. In fact, it was known that those who harbour a SNP (Asn46/Ser46) in the gene enconding Sirt6 show a better outcome those individuals who are homozygous for the Asn 46 allele. We found that fibroblasts and iPSC-derived neurons from FRDA patients harboring the SNP (Asn46/Ser46) have a reduced amount of Sirt6 protein compared to cells from individuals who are homozygous for the prevalent Asn allele. Our studies provide new information on the role of Sirtuins in FRDA pathogenesis

Gender at Work in Southeast Asia: Norms, Expectations and Local Manipulations

Research carried out by some of the contributors to WP3 addresses more or less directly the issue of gender in Southeast Asia and utilizes gender as a perspective to engage with issues of work and social and political mobility. In doing so, we acknowledge both dominant and marginal constructions and conceptions of gender and gender roles and explore the meanings attached to such ideas and notions at a local level. The work of WP3 indeed challenges the idea that local gender identity constructions are being swept away on the tide of globalization. Rather, we are aware that such constructions are reworked, rethought and that while some are reiterated others are creatively manipulated to comply with change and new expectations. Such work of WP3 highlights the ways local cultural understandings of femininity and masculinity are always framed against the history and contemporary socio-economic realities of the specific country at a specific time with specific results and outcomes

Aerobic Training Affects Fatty Acid Composition of Erythrocyte Membranes

The effect of exercise training on the fatty acid composition of erythrocyte membranes was evaluated in an experimental animal model where rats were subjected to a ten-wk aerobic training. Five groups of rats were compared: sedentary rats at 19 or 23 wks of age, rats trained at moderate or high intensity sacrificed at 19 wks of age, and rats trained at high intensity, and sacrificed following 4 weeks of sedentary life. We had already demonstrated that cardioprotection correlates with training intensity and partially persists in detrained rats. Main findings are that rats trained at higher intensity display consistent signs of lipid peroxidation but a lower ω6/ω3 ratio and a lower content of trans fatty acids when compared to rats trained at lower intensity and to older sedentary rats. Trans fatty acids negatively affect cell membrane fluidity and permeability. Detrained rats showed intermediate values. Gene expression evaluation of selected enzymes involved in lipid biosynthesis revealed some of the adaptive mechanisms leading to the maintenance of membrane fatty acid homeostasis following exercise. The decrease in the amount of trans fatty and in the inflammatory pathways (i.e. ω6/ω3 ratio) in high-intensity trained rats underscores the protective effect of high intensity aerobic training

Frataxin mRNA isoforms in FRDA patients and normal subjects: effect of tocotrienol supplementation.

Friedreich's ataxia (FRDA) is caused by deficient expression of the mitochondrial protein frataxin involved in the formation of iron-sulphur complexes, and by consequent oxidative stress. We analysed low-dose tocotrienol supplementation effects on the expression of the three splice variant isoforms (FXN-1, FXN-2 and FXN-3) in mononuclear blood cells of FRDA patients and healthy subjects. In FRDA patients, tocotrienol leads to a specific and significant increase of FXN-3 expression, while not affecting FXN-1 and FXN-2 expression. Since no structural and functional details were available for FNX-2 and FXN-3, 3D-models were built. FXN-1, the canonical isoform, was then docked on the human iron-sulphur complex and functional interactions were computed; when FXN-1 was replaced by FXN-2 or FNX-3, we found that the interactions were maintained, thus suggesting a possible biological role for both isoforms in human cells. Finally, in order to evaluate whether tocotrienol enhancement of FXN-3 was mediated by an increase in peroxisome proliferator-activated receptor-\uf067 (PPARG), PPARG expression was evaluated. At low dose of tocotrienol, the increase of FXN-3 expression appeared to be independent of PPARG expression. Our data show that it is possible to modulate the mRNA expression of the minor frataxin isoforms, and that they may have a functional role

Non-Thermal Radio Frequency and Static Magnetic Fields Increase Rate of Hemoglobin Deoxygenation in a Cell-Free Preparation

The growing body of clinical and experimental data regarding electromagnetic field (EMF) bioeffects and their therapeutic applications has contributed to a better understanding of the underlying mechanisms of action. This study reports that two EMF modalities currently in clinical use, a pulse-modulated radiofrequency (PRF) signal, and a static magnetic field (SMF), applied independently, increased the rate of deoxygenation of human hemoglobin (Hb) in a cell-free assay. Deoxygenation of Hb was initiated using the reducing agent dithiothreitol (DTT) in an assay that allowed the time for deoxygenation to be controlled (from several min to several hours) by adjusting the relative concentrations of DTT and Hb. The time course of Hb deoxygenation was observed using visible light spectroscopy. Exposure for 10–30 min to either PRF or SMF increased the rate of deoxygenation occurring several min to several hours after the end of EMF exposure. The sensitivity and biochemical simplicity of the assay developed here suggest a new research tool that may help to further the understanding of basic biophysical EMF transduction mechanisms. If the results of this study were to be shown to occur at the cellular and tissue level, EMF-enhanced oxygen availability would be one of the mechanisms by which clinically relevant EMF-mediated enhancement of growth and repair processes could occur

Advanced glycation endproducts, dityrosine and arginine transporter dysfunction in autism - a source of biomarkers for clinical diagnosis.

Background: Clinical chemistry tests for autism spectrum disorder (ASD) are currently unavailable. The aim of this study was to explore the diagnostic utility of proteotoxic biomarkers in plasma and urine, plasma protein glycation, oxidation, and nitration adducts, and related glycated, oxidized, and nitrated amino acids (free adducts), for the clinical diagnosis of ASD. Methods: Thirty-eight children with ASD (29 male, 9 female; age 7.6 \ub1 2.0 years) and 31 age-matched healthy controls (23 males, 8 females; 8.6 \ub1 2.0 years) were recruited for this study. Plasma protein glycation, oxidation, and nitration adducts and amino acid metabolome in plasma and urine were determined by stable isotopic dilution analysis liquid chromatography-tandem mass spectrometry. Machine learning methods were then employed to explore and optimize combinations of analyte data for ASD diagnosis. Results: We found that children with ASD had increased advanced glycation endproducts (AGEs), N\u3b5-carboxymethyllysine (CML) and N\u3c9-carboxymethylarginine (CMA), and increased oxidation damage marker, dityrosine (DT), in plasma protein, with respect to healthy controls. We also found that children with ASD had increased CMA free adduct in plasma ultrafiltrate and increased urinary excretion of oxidation free adducts, alpha-aminoadipic semialdehyde and glutamic semialdehyde. From study of renal handling of amino acids, we found that children with ASD had decreased renal clearance of arginine and CMA with respect to healthy controls. Algorithms to discriminate between ASD and healthy controls gave strong diagnostic performance with features: plasma protein AGEs\u2014CML, CMA\u2014and 3-deoxyglucosonederived hydroimidazolone, and oxidative damage marker, DT. The sensitivity, specificity, and receiver operating characteristic area-under-the-curve were 92%, 84%, and 0.94, respectively. Conclusions: Changes in plasma AGEs were likely indicative of dysfunctional metabolism of dicarbonyl metabolite precursors of AGEs, glyoxal and 3-deoxyglucosone. DT is formed enzymatically by dual oxidase (DUOX); selective increase of DT as an oxidative damage marker implicates increased DUOX activity in ASD possibly linked to impaired gutmucosal immunity. Decreased renal clearance of arginine and CMA in ASD is indicative of increased arginine transporter activity which may be a surrogate marker of disturbance of neuronal availability of amino acids. Data driven combination of these biomarkers perturbed by proteotoxic stress, plasma protein AGEs and DT, gave diagnostic algorithms of high sensitivity and specificity for ASD

Aerobic training affects fatty acid composition of erythrocyte membranes

Abstract The effect of exercise training on the fatty acid composition of erythrocyte membranes was evaluated in an experimental animal model where rats were subjected to a ten-wk aerobic training. Five groups of rats were compared: sedentary rats at 19 or 23 wks of age, rats trained at moderate or high intensity sacrificed at 19 wks of age, and rats trained at high intensity, and sacrificed following 4 weeks of sedentary life. We had already demonstrated that cardioprotection correlates with training intensity and partially persists in detrained rats. Main findings are that rats trained at higher intensity display consistent signs of lipid peroxidation but a lower ω6/ω3 ratio and a lower content of trans fatty acids when compared to rats trained at lower intensity and to older sedentary rats. Trans fatty acids negatively affect cell membrane fluidity and permeability. Detrained rats showed intermediate values. Gene expression evaluation of selected enzymes involved in lipid biosynthesis revealed some of the adaptive mechanisms leading to the maintenance of membrane fatty acid homeostasis following exercise. The decrease in the amount of trans fatty and in the inflammatory pathways (i.e. ω6/ω3 ratio) in high-intensity trained rats underscores the protective effect of high intensity aerobic training.</p

New Insights into the Hepcidin-Ferroportin Axis and Iron Homeostasis in iPSC-Derived Cardiomyocytes from Friedreich’s Ataxia Patient

Iron homeostasis in the cardiac tissue as well as the involvement of the hepcidin-ferroportin (HAMP-FPN) axis in this process and in cardiac functionality are not fully understood. Imbalance of iron homeostasis occurs in several cardiac diseases, including iron-overload cardiomyopathies such as Friedreich’s ataxia (FRDA, OMIM no. 229300), a hereditary neurodegenerative disorder. Exploiting the induced pluripotent stem cells (iPSCs) technology and the iPSC capacity to differentiate into specific cell types, we derived cardiomyocytes of a FRDA patient and of a healthy control subject in order to study the cardiac iron homeostasis and the HAMP-FPN axis. Both CTR and FRDA iPSCs-derived cardiomyocytes express cardiac differentiation markers; in addition, FRDA cardiomyocytes maintain the FRDA-like phenotype. We found that FRDA cardiomyocytes show an increase in the protein expression of HAMP and FPN. Moreover, immunofluorescence analysis revealed for the first time an unexpected nuclear localization of FPN in both CTR and FRDA cardiomyocytes. However, the amount of the nuclear FPN was less in FRDA cardiomyocytes than in controls. These and other data suggest that iron handling and the HAMP-FPN axis regulation in FRDA cardiac cells are hampered and that FPN may have new, still not fully understood, functions. These findings underline the complexity of the cardiac iron homeostasis