In Subfertile Couple, Abdominal Fat Loss in Men Is Associated with Improvement of Sperm Quality and Pregnancy: A Case-Series

International audienceBackground: The impact of overweight among men of reproductive-age may affect fertility. Abdominal fat, more than body mass index, is an indicator of higher metabolic risk, which seems to be involved in decreasing sperm quality. This study aims to assess the relationship between abdominal fat and sperm DNA fragmentation and the effect of abdominal fat loss, among 6 men in subfertile couples. Methods: Sperm DNA fragmentation, abdominal fat and metabolic and hormonal profiles were measured in the 6 men before and after dietary advices. Seminal oxidative stress and antioxidant markers were determined. Results: After several months of a lifestyle program, all 6 men lost abdominal fat (patient 1: loss of 3 points of abdominal fat, patient 2: loss of 3 points, patient 3: loss of 2 points, patient 4: loss of 1 point, patient 5: loss of 4 points and patient 6: loss of 13 points). At the same time, their rate of sperm DNA fragmentation decreased: 9.5% vs 31%, 24% vs 43%, 18% vs 47%, 26.3% vs 66%, 25.4% vs 35% and 1.7% vs 25%. Also, an improvement in both metabolic (significant decrease in triglycerides and total cholesterol; p = 0.0139) and hormonal (significant increase in testosterone/oestradiol ratio; p = 0.0139) blood profiles was observed after following the lifestyle program. In seminal plasma, the amount of SOD2 has significantly increased (p = 0.0139) while in parallel carbonylated proteins have decreased. Furthermore, all spouses got pregnant. All pregnancies were brought to term. Conclusion: This study shows specifically that sperm DNA fragmentation among men in subfertile couples could be affected by abdominal fat, but improvement of lifestyle factor may correct this alteration. The effect of specific abdominal fat loss on sperm quality needs further investigation. The reduction of oxidative stress may be a contributing factor

Changes of the Proteasomal System During the Aging Process

International audienceAccumulation of oxidized and damaged proteins is a hallmark of the aging process in different organs and tissues. Intracellular protein degradation is normally the most efficient mechanism to prevent toxicity associated with the accumulation of altered proteins without affecting the cellular reserves of amino acids. Protein degradation by the proteasomal system is a key process for the maintenance of cellular protein homeostasis and has come into the focus of aging research during the last decade. During the last few years, several lines of evidence have indicated that proteasome function is impaired during aging, suggesting that this decreased activity might be causally related to the aging process and the occurrence of age-associated diseases. This chapter reviews the proteasome status in organs, tissues, cells, and model organisms during aging as well as the molecular mechanisms involved in the age-related decline of proteasome function. Finally, interventions aimed at rejuvenating proteasome function as a potential antiaging strategy are discussed

Proteomic quantification and identification of carbonylated proteins upon oxidative stress and during cellular aging

International audienceIncreased protein carbonyl content is a hallmark of cellular and organismal aging. Protein damage leading to the formation of carbonyl groups derives from direct oxidation of several amino acid side chains but can also derive through protein adducts formation with lipid peroxidation products and dicarbonyl glycating compounds. All these modifications have been implicated during oxidative stress, aging and age-related diseases. However, in most cases, the proteins targeted by these deleterious modifications as well as their consequences have not yet been clearly identified. Indeed, this is essential to determine whether and how these modified proteins are impacting on cellular function, on the development of the senescent phenotype and the pathogenesis of age-related diseases. In this context, protein modifications occurring during aging and upon oxidative stress as well as main proteomic methods for detecting, quantifying and identifying oxidized proteins are described. Relevant proteomics studies aimed at monitoring the extent of protein carbonylation and identifying the targeted proteins in the context of aging and oxidative stress are also presented. Proteomics approaches, i.e. fluorescent based 2D-gel electrophoresis and mass spectrometry methods, represent powerful tools for monitoring at the proteome level the extent of protein oxidative and related modifications and for identifying the targeted proteins. Biological significance Accumulation of damaged macromolecules, including oxidatively damaged (carbonylated) proteins, is a hallmark of cellular and organismal aging. Since protein carbonyls are the most commonly used markers of protein oxidation, different methods have been developed for the detection and quantification of carbonylated proteins. The identification of these protein targets is of valuable interest in order to understand the mechanisms by which damaged proteins accumulate and potentially affect cellular functions during oxidative stress, cellular senescence and/or aging in vivo. The specificity of hydrazide derivatives to carbonyl groups and the presence of a wide range of functional groups coupled to the hydrazide, allowed the design of novel strategies for the detection and quantification of carbonylated proteins. Of note is the importance of fluorescent probes for monitoring carbonylated proteins. Proteomics approaches, i.e. fluorescent based 2D-gel electrophoresis and mass spectrometry methods, represent powerful tools for monitoring at the proteome level the extent of protein oxidative and related modifications and for identifying the targeted proteins

Protein Carbonylation as a Reliable Read-Out of Urban Pollution Damage/Protection of Hair Fibers

(1) Background: Environmental factors, such as airborne pollutants and solar UV, induce oxidative damage to proteins and lipids on hair fibers, leading to decreased hair strength and shine, increased fiber porosity, brittleness, dryness, and stiffness. Traditional methods used for hair damage/protection/reparation assessment show limitations in sensitivity or specificity for evidencing the benefits to be gained from the protection/reparation of hair fibers against environmental stressors. (2) Methods: Ex vivo experimental models of hair fibers exposed to urban pollutants and UV irradiation were developed. Targeted proteomics approaches for the quantification of oxidatively damaged (carbonylated) proteins on hair fibers were optimized. (3) Results: A significant dose-dependent increase in carbonylation both in the cuticle and cortex proteins was observed upon exposure of hair fibers to particulate matter and UV-A radiation, at daily stress equivalent doses. Increased protein carbonylation on keratins and keratin-associated proteins led to loss of hair fiber structural integrity. The oxidative modification of proteins induced by urban pollution exposure led to hair cuticle structural damage revealed by an increased permeability. However, protein carbonylation was prevented in the presence of antioxidant compounds. (4) Conclusions: Protein carbonylation is an early event in hair fiber damage which can be used as a reliable biomarker for the efficacy of hair care interventions against environmental stressors

Protein Carbonylation as a Reliable Read-Out of Urban Pollution Damage/Protection of Hair Fibers

(1) Background: Environmental factors, such as airborne pollutants and solar UV, induce oxidative damage to proteins and lipids on hair fibers, leading to decreased hair strength and shine, increased fiber porosity, brittleness, dryness, and stiffness. Traditional methods used for hair damage/protection/reparation assessment show limitations in sensitivity or specificity for evidencing the benefits to be gained from the protection/reparation of hair fibers against environmental stressors. (2) Methods: Ex vivo experimental models of hair fibers exposed to urban pollutants and UV irradiation were developed. Targeted proteomics approaches for the quantification of oxidatively damaged (carbonylated) proteins on hair fibers were optimized. (3) Results: A significant dose-dependent increase in carbonylation both in the cuticle and cortex proteins was observed upon exposure of hair fibers to particulate matter and UV-A radiation, at daily stress equivalent doses. Increased protein carbonylation on keratins and keratin-associated proteins led to loss of hair fiber structural integrity. The oxidative modification of proteins induced by urban pollution exposure led to hair cuticle structural damage revealed by an increased permeability. However, protein carbonylation was prevented in the presence of antioxidant compounds. (4) Conclusions: Protein carbonylation is an early event in hair fiber damage which can be used as a reliable biomarker for the efficacy of hair care interventions against environmental stressors

Protein Oxidative Damage at the Crossroads of Cellular Senescence, Aging, and Age-Related Diseases

Protein damage mediated by oxidation, protein adducts formation with advanced glycated end products and with products of lipid peroxidation, has been implicated during aging and age-related diseases, such as neurodegenerative diseases. Increased protein modification has also been described upon replicative senescence of human fibroblasts, a valid model for studying aging in vitro. However, the mechanisms by which these modified proteins could impact on the development of the senescent phenotype and the pathogenesis of age-related diseases remain elusive. In this study, we performed in silico approaches to evidence molecular actors and cellular pathways affected by these damaged proteins. A database of proteins modified by carbonylation, glycation, and lipid peroxidation products during aging and age-related diseases was built and compared to those proteins identified during cellular replicative senescence in vitro. Common cellular pathways evidenced by enzymes involved in intermediate metabolism were found to be targeted by these modifications, although different tissues have been examined. These results underscore the potential effect of protein modification in the impairment of cellular metabolism during aging and age-related diseases

Photosensitized reactions mediated by the major chromophore arising from glucose decomposition, result in oxidation and cross-linking of lens proteins and activation of the proteasome

International audienceGlucose solutions incubated at low oxygen concentration gave rise to the appearance of an absorption band in the UVA-visible region after 10 days. Further characterization evidenced that this band was composed by a single chomophore with maximum absorption bands at 335 and 365 nm. HPLC/MS and UV spectroscopy assays indicated that this product is composed by five unities of furan. Importantly, the presence of a compound with identical spectral and chromatographic properties was observed in the water-soluble fraction of cataractous human eye lenses. The photo-biological effects of this glucose-derived chromophore (GDC) have been addressed using targets of biological relevance, such as water-soluble proteins from eye lens and the proteasome present in this protein mixture. Increased protein oxidation and protein crosslinking was observed when lens proteins were exposed to UVA-visible light in the presence of GDC under a 5% and 20% oxygen atmosphere. In addition, an increased proteasome peptidase activity was also observed. However, the use of D2O resulted in decreased proteasome activity, suggesting that singlet oxygen promotes the impairment of proteasome activity. Our results suggest that the species generated by Type I and Type II mechanisms have opposite effects on proteasome activity, being Type I a positive activator while Type II lead to impairment of proteasome function

Oxidative proteome alterations during skeletal muscle ageing

Sarcopenia corresponds to the degenerative loss of skeletal muscle mass, quality, and strength associated with ageing and leads to a progressive impairment of mobility and quality of life. However, the cellular and molecular mechanisms involved in this process are not completely understood. A hallmark of cellular and tissular ageing is the accumulation of oxidatively modified (carbonylated) proteins, leading to a decreased quality of the cellular proteome that could directly impact on normal cellular functions. Although increased oxidative stress has been reported during skeletal muscle ageing, the oxidized protein targets, also referred as to the 'oxi-proteome' or 'carbonylome', have not been characterized yet. To better understand the mechanisms by which these damaged proteins build up and potentially affect muscle function, proteins targeted by these modifications have been identified in human rectus abdominis muscle obtained from young and old healthy donors using a bi-dimensional gel electrophoresis-based proteomic approach coupled with immunodetection of carbonylated proteins. Among evidenced protein spots, 17 were found as increased carbonylated in biopsies from old donors comparing to young counterparts. These proteins are involved in key cellular functions such as cellular morphology and transport, muscle contraction and energy metabolism. Importantly, impairment of these pathways has been described in skeletal muscle during ageing. Functional decline of these proteins due to irreversible oxidation may therefore impact directly on the above-mentioned pathways, hence contributing to the generation of the sarcopenic phenotype