Effect of the 35 nm and 70 nm Size Exclusion Chromatography (SEC) Column and Plasma Storage Time on Separated Extracellular Vesicles.

The technical difficulty of separating extracellular vesicles (EVs) from plasma proteins in human blood presents a significant hurdle in EV research, particularly during nano ultra-high-performance liquid chromatography-tandem mass spectrometric (UHPLC-MS/MS) analysis, where detecting "vesicular" proteins among abundant plasma proteins is challenging. Standardisation is a pressing issue in EV research, prompting collaborative global efforts to address it. While the MISEV guidelines offer valuable recommendations, unanswered questions remain, particularly regarding sample storage. We compared size exclusion chromatography (SEC) columns with pore sizes of 35 nm and 70 nm to identify fractions with minimal contaminating proteins and the highest concentration of small EVs (sEVs). Following column selection, we explored potential differences in the quality and quantity of sEVs isolated from platelet-free plasma (PFP) after long-term storage at -80 °C (>2.5 years) compared to freshly drawn blood. Our methodologically rigorous study indicates that prolonged storage, under correct storage and processing conditions, does not compromise sEV quality. Both columns effectively isolated vesicles, with the 70 nm column exhibiting a higher abundance of "vesicular" proteins. We propose a relatively rapid and moderately efficient protocol for obtaining a comparatively pure sEV fraction from plasma, facilitating sEV processing in clinical trials.

Physical Exercise-Induced Activation of NRF2 and BDNF as a Promising Strategy for Ferroptosis Regulation in Parkinson's Disease.

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra. Ferroptosis, an iron-dependent form of regulated cell death, may contribute to the progression of PD owing to an unbalanced brain redox status. Physical exercise is a complementary therapy that can modulate ferroptosis in PD by regulating the redox system through the activation of nuclear factor (erythroid-derived 2)-like 2 (NRF2) and brain-derived neurotrophic factor (BDNF) signaling. However, the precise effects of physical exercise on ferroptosis in PD remain unclear. In this review, we explored how physical exercise influences NRF2 and BDNF signaling and affects ferroptosis in PD. We further investigated relevant publications over the past two decades by searching the PubMed, Web of Science, and Google Scholar databases using keywords related to physical exercise, PD, ferroptosis, and neurotrophic factor antioxidant signaling. This review provides insights into current research gaps and demonstrates the necessity for future research to elucidate the specific mechanisms by which exercise regulates ferroptosis in PD, including the assessment of different exercise protocols and their long-term effects. Ultimately, exploring these aspects may lead to the development of improved exercise interventions for the better management of patients with PD.

Exercise combined with postbiotics treatment results in synergistic improvement of mitochondrial function in the brain of male transgenic mice for Alzheimer's disease.

BACKGROUND: It has been suggested that exercise training and postbiotic supplement could decelerate the progress of functional and biochemical deterioration in double transgenic mice overexpresses mutated forms of the genes for human amyloid precursor protein (APPsw) and presenilin 1 (m146L) (APP/PS1TG). Our earlier published data indicated that the mice performed better than controls on the Morris Maze Test parallel with decreased occurrence of amyloid-ß plaques in the hippocampus. We investigated the neuroprotective and therapeutic effects of high-intensity training and postbiotic supplementation. METHODS: Thirty-two adult APP/PS1TG mice were randomly divided into four groups: (1) control, (2) high-intensity training (3) postbiotic, (4) combined (training and postbiotic) treatment for 20 weeks. In this study, the whole hemibrain without hippocampus was used to find molecular traits explaining improved brain function. We applied qualitative RT-PCR for gene expression, Western blot for protein level, and Zymography for LONP1 activity. Disaggregation analysis of Aß-40 was performed in the presence of Lactobacillus acidophilus and Bifidobacterium longum lysate. RESULTS: We found that exercise training decreased Alzheimer's Disease (AD)-related gene expression (NF-kB) that was not affected by postbiotic treatment. The preparation used for postbiotic treatment is composed of tyndallized Bifidobacterium longum and Lactobacillus acidophilus. Both of the postbiotics effectively disaggregated amyloid-ß/Aß-40 aggregates by chelating Zn2+ and Cu2+ ions. The postbiotic treatment decreased endogenous human APPTG protein expression and mouse APP gene expression in the hemibrains. In addition, the postbiotic treatment elevated mitochondrial LONP1 activity as well. CONCLUSION: Our findings revealed distinct mechanisms behind improved memory performance in the whole brain: while exercise training modulates NF-kB signaling pathway regulating immune response until postbiotic diminishes APP gene expression, disaggregates pre-existing amyloid-ß plaques and activates mitochondrial protein quality control in the region of brain out of hippocampus. Using the above treatments complements and efficiently slows down the development of AD.

"Slight chemical damage due to drinking modest amount of sake, might induce beneficial effects" as a form of hormesis: an interview with Professor Sataro Goto.

Professor Sataro Goto is one of the pioneers of biological aging research in Japan. He is renowned for his work on the role of protein errors and modifications, the accumulation of abnormal proteins due to reduced protein turnover, and the modulation of aging and lifespan by adult-onset dietary restriction and regular exercise. Professor Goto is a remarkably intelligent, visionary, empathetic, humble, and wise man, who kindly agreed to this interview that I (Zsolt Radak) made with him during one of my frequent visits to his labs, in February 2023.

No strong association among epigenetic modifications by DNA methylation, telomere length, and physical fitness in biological aging.

Cellular senescence is greatly accelerated by telomere shortening, and the steps forward in human aging are strongly influenced by environmental and lifestyle factors, whether DNA methylation (DNAm) is affected by exercise training, remains unclear. In the present study, we investigated the relationships between physiological functions, maximal oxygen uptake (VO2max), vertical jump, working memory, telomere length (TL) assessed by RT-PCR, DNA methylation-based estimation of TL (DNAmTL), and DNA methylation-based biomarkers of aging of master rowers (N = 146) and sedentary subjects (N = 95), aged between 37 and 85 years. It was found that the TL inversely correlated with chronological age. We could not detect an association between telomere length and VO2max, vertical jump, and working memory by RT-PCR method, while these physiological test results showed a correlation with DNAmTL. DNAmGrimAge and DNAmPhenoAge acceleration were inversely associated with telomere length assessed by both methods. It appears that there are no strong beneficial effects of exercise or physiological fitness on telomere shortening, however, the degree of DNA methylation is associated with telomere length.

Age-Related Declines in Lower Limb Muscle Function are Similar in Power and Endurance Athletes of Both Sexes: A Longitudinal Study of Master Athletes.

The age-related decline in muscle function, particularly muscle power, is associated with increased risk of important clinical outcomes. Physical activity is an important determinant of muscle function, and different types of physical activity e.g. power-based versus endurance-based exercise appear to have differential effects on muscle power. Cross-sectional studies suggest that participation in power-based exercise is associated with greater muscle power across adulthood but this has not been investigated longitudinally. We recruited eighty-nine male and female power and endurance master athletes (sprint and distance runners respectively, baseline age 35-90y). Using jumping mechanography, we measured lower limb muscle function during a vertical jump including at least two testing sessions longitudinally over 4.5 ± 2.4y. We examined effects of time, discipline (power/endurance) and sex in addition to two- and three-way interactions using linear mixed-effects models. Peak relative power, relative force and jump height, but not Esslingen Fitness Index (indicating peak power relative to sex and age-matched reference data) declined with time. Peak power, force, height and EFI were greater in power than endurance athletes. There were no sex, discipline or sex*discipline interactions with time for any variable, suggesting that changes were similar over time for athletes of both sexes and disciplines. Advantages in lower limb muscle function in power athletes were maintained with time, in line with previous cross-sectional studies. These results suggest that improvements in lower limb function in less active older individuals following power-based training persist with continued adherence, although this requires further investigation in interventional studies.

Physical Training Protects Against Brain Toxicity in Mice Exposed to an Experimental Model of Glioblastoma.

Glioma 261 (Gl261) cell-mediated neurotoxicity has been reported in previous studies examining glioblastoma (GBM), and the effects of physical exercise (PE) on this neurotoxicity have been poorly investigated. This study aimed to evaluate the effects of a PE program in animals with experimental GBM. Male C57BL/6J mice were randomized into sham or GBM groups and subjected to a PE program for four weeks. Gl261 cells were administered into the intraventricular region at 48 h after the last exercise session. Body weight, water and feed consumption, and behavior were all evaluated for 21 days followed by euthanasia. The right parietal lobe was removed for the analysis of glial fibrillary acidic protein (GFAP), epidermal growth factor receptor (EGFR), vimentin, C-myc, nuclear factor kappa B (NF-κB), tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1ß), interleukin 6 (IL-6), hydrogen peroxide, the glutathione system, and oxidative damage to proteins. The results revealed changes in the behavioral patterns of the trained animals, and no anatomopathological changes were observed in response to PE training. In contrast, animals with GBM subjected to PE exhibited lower immunoexpression of c-MYC, vimentin, and GFAP. Although experimental GBM altered the redox profile and inflammatory mediators, no significant alterations were observed after PE. In conclusion, our data provide consistent evidence of the relationship between PE and the improvement of tumorigenic parameters against the neurotoxicity of GL261 cells.

Exercise-mitigated sex-based differences in aging: from genetic alterations to heart performance.

The prevalence of cardiovascular diseases dramatically increases with age; therefore, striving to maintain a physiological heart function is particularly important. Our aim was to study the voluntary exercise-evoked cardioprotective effects in aged male and female rats, from genetic alterations to changes in heart performance. We divided 20-month-old female and male Wistar rats to control and running groups. After the 12-wk-long experimental period, echocardiographic measurements were performed. Afterwards, hearts were either removed for biochemical measurements or mounted into a Langendorff-perfusion system to detect infarct size. The following genes and their proteins were analyzed from heart: catechol-O-methyltransferase (Comt), endothelin-1 (Esm1), Purkinje cell protein-4 (Pcp4), and osteoglycin (Ogn). Recreational exercise caused functional improvements; however, changes were more prominent in males. Cardiac expression of Comt and Ogn was reduced as a result of exercise in aged males, whereas Pcp4 and Esm1 showed a marked overexpression, along with a markedly improved diastolic function. The key result of this study is that exercise enhanced the expression of the Pcp4 gene and protein, a recently described regulator of calcium balance in cardiomyocytes, and suppressed Comt and Ogn gene expression, which has been associated with impaired cardiac function. In addition, as a result of exercise, a significant improvement was observed in the size of infarct elicited by left anterior descending coronary artery occlusion. Our results clearly show that age and sex-dependent changes were both apparent in key proteins linked to cardiovascular physiology. Exercise-moderated fundamental genetic alterations may have contributed to the functional adaptation of the heart.NEW & NOTEWORTHY Voluntary exercise has proved to be an effective therapeutic tool to improve cardiac function in aged rats with clearly visible sex differences. Long-term exercise is associated with decreased Ogn and Comt expression and enhanced presence of Pcp4 and Esm1 genes. Sex-dependent changes were also observed in the expression of the cardiovascular key proteins. Fundamental alterations in gene and protein expression may contribute to the improvement of cardiac performance.

Hypertrophy of Rat Skeletal Muscle Is Associated with Increased SIRT1/Akt/mTOR/S6 and Suppressed Sestrin2/SIRT3/FOXO1 Levels.

Despite the intensive investigation of the molecular mechanism of skeletal muscle hypertrophy, the underlying signaling processes are not completely understood. Therefore, we used an overload model, in which the main synergist muscles (gastrocnemius, soleus) of the plantaris muscle were surgically removed, to cause a significant overload in the remaining plantaris muscle of 8-month-old Wistar male rats. SIRT1-associated pro-anabolic, pro-catabolic molecular signaling pathways, NAD and H2S levels of this overload-induced hypertrophy were studied. Fourteen days of overload resulted in a significant 43% (p < 0.01) increase in the mass of plantaris muscle compared to sham operated animals. Cystathionine-ß-synthase (CBS) activities and bioavailable H2S levels were not modified by overload. On the other hand, overload-induced hypertrophy of skeletal muscle was associated with increased SIRT1 (p < 0.01), Akt (p < 0.01), mTOR, S6 (p < 0.01) and suppressed sestrin 2 levels (p < 0.01), which are mostly responsible for anabolic signaling. Decreased FOXO1 and SIRT3 signaling (p < 0.01) suggest downregulation of protein breakdown and mitophagy. Decreased levels of NAD+, sestrin2, OGG1 (p < 0.01) indicate that the redox milieu of skeletal muscle after 14 days of overloading is reduced. The present investigation revealed novel cellular interactions that regulate anabolic and catabolic processes in the hypertrophy of skeletal muscle.

Exercise combined with a probiotics treatment alters the microbiome, but moderately affects signalling pathways in the liver of male APP/PS1 transgenic mice.

It has been demonstrated that physical exercise and probiotic supplementation delay the progress of Alzheimer's Disease (AD) in male APP/PS1TG mice. However, it has also been suggested that both exercise and AD have systemic effects. We have studied the effects of exercise training and probiotic treatment on microbiome and biochemical signalling proteins in the liver. The results suggest that liver is under oxidative stress, since SOD2 levels of APP/PS1 mice were decreased when compared to a wild type of mice. Exercise training prevented this decrease. We did not find significant changes in COX4, SIRT3, PGC-1a or GLUT4 levels, while the changes in pAMPK/AMPK, pmTOR/mTOR, pS6/S6 and NRF2 levels were randomly modulated. The data suggest that exercise and probiotics-induced changes in microbiome do not strongly affect mitochondrial density or protein synthesis-related AMPK/mTOR/S6 pathways in the liver of these animals.

Absence of an aging-related increase in fiber type grouping in athletes and non-athletes.

The aging-related loss of muscle mass is thought to be partly attributable to motor neuron loss and motor unit remodeling that result in fiber type grouping. We examined fiber type grouping in 19- to 85-year-old athletes and non-athletes and evaluated to which extent any observed grouping is explained by the fiber type composition of the muscle. Since regular physical activity may stimulate reinnervation, we hypothesized that fiber groups are larger in master athletes than in age-matched non-athletes. Fiber type grouping was assessed in m. vastus lateralis biopsies from 22 young (19-27 years) and 35 healthy older (66-82 years) non-athletes, and 14 young (20-29 years), 51 middle-aged (38-65 years), and 31 older (66-85 years) athletes. An "enclosed fiber" was any muscle fiber of a particular type surrounded by fibers of the same type only. A fiber type group was defined as a group of fibers with at least one enclosed fiber. Only type II fiber cross-sectional area (FCSA) showed an age-related decline that was greater in athletes (P < .001) than in non-athletes (P = .012). There was no significant age-related effect on fiber group size or fiber group number in athletes or non-athletes, and the observed grouping was similar to that expected from the fiber type composition. At face value, these observations do 1) neither show evidence for an age-related loss and remodeling of motor units nor 2) improved reinnervation with regular physical activity, but 3) histological examination may not reveal the full extent of aging-related motor unit remodeling.

Alzheimer's Disease Mouse as a Model of Testis Degeneration.

Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide with protective functions in the central nervous system and various peripheral organs. PACAP has the highest expression level in the testes, among the peripheral organs, and has a positive regulative role in spermatogenesis and in sperm motility. In the present study, we explored testicular degenerative alterations in a mouse model of Alzheimer's disease (AD) (B6C3-Tg(APPswe,PSEN1dE9)85Dbo/J) and demonstrated changes in PACAP-regulated signaling pathways. In addition, the effects of increased physical activity of AD (trained AD (TAD)) mice on testis were also followed. Reduced cell number and decreased thickness of basement membrane were detected in AD samples. These changes were compensated by physical activity. Expression of PACAP receptors and canonical signaling elements such as PKA, P-PKA, PP2A significantly decreased in AD mice, and altered Sox transcription factor expression was also detected. Via this signaling mechanism, physical activity compensated the negative effects of AD on the expression of type IV collagen. Our findings suggest that the testes of AD mice can be a good model of testis degeneration. Moreover, it can be an appropriate organ to follow the effects of various interventions such as physical activity on tissue regeneration and signaling alterations.

Freestyle gymnastic exercise can be used to assess complex coordination in a variety of sports.

OBJECTIVE: The assessment of motor coordination is a very complex process and demonstrates a high degree of sport specificity. There are a limited number of tests, if any, where results correlate with the success rate of athletes in different sports. METHODS: Free style gymnastic exercise (FSGE) and coordination ball dribbling exercise (CBDE) were used to see whether the execution quality of these tests is related to the quality of athletes from team handball, water polo, kayak, rhythmical gymnastics (RG) and aerobics (222 athletes - 75 male, 147 female; 23 non-athletes - 9 male, 14 female). RESULTS: FSGE results related to the quality of performance in all sports (r = -0.232, p < 0.01 in handball, water polo, kayak and r = -0.26, p < 0.05 in aerobics and RG), while CBDE did not. Older players had higher ranking as they had more time to be successful at their sport (r = -0.498, p < 0.01 in handball, water polo, kayak; r = -0.298, p < 0.05 in aerobics and RG). The scores of FSGE were independent from the age and gender of the subjects. CONCLUSIONS: The main findings were: (i) that athletes did significantly better than the controls in both tests; (ii) RG and aerobics athletes did better on the FSGE than handball, water polo players and kayakers; (iii) handball players did better than kayakers, RG and aerobics athletes on the CBDE test; and (iv) better ranked athletes performed better on the FGSE test. Therefore, FSGE test appears to be a reliable test to assess coordination in variety of sport and different levels of sport performance.

The Effects of Exercise Training and High Triglyceride Diet in an Estrogen Depleted Rat Model: The Role of the Heme Oxygenase System and Inflammatory Processes in Cardiovascular Risk.

Cardiovascular morbidity and mortality of premenopausal women are significantly lower compared to men of similar age. However, this protective effect evidently decreases after the onset of menopause. We hypothesized that physical exercise could be a potential therapeutic strategy to improve inflammatory processes and cardiovascular antioxidant homeostasis, which can be affected by the loss of estrogen and the adverse environmental factors, such as overnutrition. Ovariectomized (OVX, n= 40) and sham-operated (SO, n= 40) female Wistar rats were randomized to exercising (R) and non-exercising (NR) groups. Feeding parameters were chosen to make a standard chow (CTRL) or a high triglyceride diet (HT) for 12 weeks. Aortic and cardiac heme oxygenase (HO) activity and HO-1 concentrations significantly decreased in all of the NR OVX and SO HT groups. However, the 12-week physical exercise was found to improve HO-1 values. Plasma IL-6 concentrations were higher in the NR OVX animals and rats fed HT diet compared to SO CTRL rats. TNF-α concentrations were significantly higher in the NR OVX groups. 12 weeks of exercise significantly reduced the concentrations of both TNF-α and IL-6 compared to the NR counterparts. The activity of myeloperoxidase enzyme (MPO) was significantly increased as a result of OVX and HT diet, however voluntary wheel-running exercise restored the elevated values. Our results show that estrogen deficiency and HT diet caused a significant decrease in the activity and concentration of HO enzyme, as well as the concentrations of TNF-α, IL-6, and the activity of MPO. However, 12 weeks of voluntary wheel-running exercise is a potential non-pharmacological therapy to ameliorate these disturbances, which determine the life expectancy of postmenopausal women.

SIRT1 may play a crucial role in overload-induced hypertrophy of skeletal muscle.

KEY POINTS: Silent mating type information regulation 2 homologue 1 (SIRT1) activity and content increased significantly in overload-induced hypertrophy. SIRT1-mediated signalling through Akt, the endothelial nitric oxide synthase mediated pathway, regulates anabolic process in the hypertrophy of skeletal muscle. The regulation of catabolic signalling via forkhead box O 1 and protein ubiquitination is SIRT1 dependent. Overload-induced changes in microRNA levels regulate SIRT1 and insulin-like growth factor 1 signalling. ABSTRACT: Significant skeletal muscle mass guarantees functional wellbeing and is important for high level performance in many sports. Although the molecular mechanism for skeletal muscle hypertrophy has been well studied, it still is not completely understood. In the present study, we used a functional overload model to induce plantaris muscle hypertrophy by surgically removing the soleus and gastrocnemius muscles in rats. Two weeks of muscle ablation resulted in a 40% increase in muscle mass, which was associated with a significant increase in silent mating type information regulation 2 homologue 1 (SIRT1) content and activity (P < 0.001). SIRT1-regulated Akt, endothelial nitric oxide synthase and GLUT4 levels were also induced in hypertrophied muscles, and SIRT1 levels correlated with muscle mass, paired box protein 7 (Pax7), proliferating cell nuclear antigen (PCNA) and nicotinamide phosphoribosyltransferase (Nampt) levels. Alternatively, decreased forkhead box O 1 (FOXO1) and increased K48 polyubiquitination also suggest that SIRT1 could be involved in the catabolic process of hypertrophy. Furthermore, increased levels of K63 and muscle RING finger 2 (MuRF2) protein could also be important enhancers of muscle mass. We report here that the levels of miR1 and miR133a decrease in hypertrophy and negatively correlate with muscle mass, SIRT1 and Nampt levels. Our results reveal a strong correlation between SIRT1 levels and activity, SIRT1-regulated pathways and overload-induced hypertrophy. These findings, along with the well-known regulatory roles that SIRT1 plays in modulating both anabolic and catabolic pathways, allow us to propose the hypothesis that SIRT1 may actually play a crucial causal role in overload-induced hypertrophy of skeletal muscle. This hypothesis will now require rigorous direct and functional testing.

Oxidized Guanine Base Lesions Function in 8-Oxoguanine DNA Glycosylase-1-mediated Epigenetic Regulation of Nuclear Factor κB-driven Gene Expression.

A large percentage of redox-responsive gene promoters contain evolutionarily conserved guanine-rich clusters; guanines are the bases most susceptible to oxidative modification(s). Consequently, 7,8-dihydro-8-oxoguanine (8-oxoG) is one of the most abundant base lesions in promoters and is primarily repaired via the 8-oxoguanine DNA glycosylase-1 (OOG1)-initiated base excision repair pathway. In view of a prompt cellular response to oxidative challenge, we hypothesized that the 8-oxoG lesion and the cognate repair protein OGG1 are utilized in transcriptional gene activation. Here, we document TNFα-induced enrichment of both 8-oxoG and OGG1 in promoters of pro-inflammatory genes, which precedes interaction of NF-κB with its DNA-binding motif. OGG1 bound to 8-oxoG upstream from the NF-κB motif increased its DNA occupancy by promoting an on-rate of both homodimeric and heterodimeric forms of NF-κB. OGG1 depletion decreased both NF-κB binding and gene expression, whereas Nei-like glycosylase-1 and -2 had a marginal effect. These results are the first to document a novel paradigm wherein the DNA repair protein OGG1 bound to its substrate is coupled to DNA occupancy of NF-κB and functions in epigenetic regulation of gene expression.

Pollen-induced oxidative DNA damage response regulates miRNAs controlling allergic inflammation.

A mucosal oxidative burst is a hallmark response to pollen exposure that promotes allergic inflammatory responses. Reactive species constituents of oxidative stress signal via the modification of cellular molecules including nucleic acids. One of the most abundant forms of oxidative genomic base damage is 8-oxo-7,8-dihydroguanine (8-oxoG), which is removed from DNA by 8-oxoguanine DNA glycosylase 1 (OGG1). OGG1 in complex with 8-oxoG acts as a GDP-GTP exchange factor and induces acute inflammation; however, the mechanism(s) by which OGG1 signaling regulates allergic airway inflammation is not known. Here, we postulate that the OGG1 signaling pathway differentially altered the levels of small regulatory RNAs and increased the expression of T helper 2 (Th2) cytokines in ragweed pollen extract (RWPE)-challenged lungs. To determine this, the lungs of sensitized mice expressing or lacking OGG1 were challenged with RWPE and/or with OGG1's excision product 8-oxoG. The responses in lungs were assessed by next-generation sequencing, as well as various molecular and histological approaches. The results showed that RWPE challenge induced oxidative burst and damage to DNA and activated OGG1 signaling, resulting in the differential expression of 84 micro-RNAs (miRNAs), which then exacerbated antigen-driven allergic inflammation and histological changes in the lungs. The exogenous administration of the downregulated let-7b-p3 mimetic or inhibitors of upregulated miR-23a or miR-27a decreased eosinophil recruitment and mucus and collagen production via controlling the expression of IL-4, IL-5, and IL-13. Together, these data demonstrate the roles of OGG1 signaling in the regulation of antigen-driven allergic immune responses via differential expression of miRNAs upstream of Th2 cytokines and eosinophils.

Exogenous nicotinamide supplementation and moderate physical exercise can attenuate the aging process in skeletal muscle of rats.

Nicotinamide (NAM) could enhance the availability of NAD+ and be beneficial to cell function. However, NAM can inhibit the activities of SIRT1 and PARP. The effect of NAM supplementation on the aging process is not well known. In the present study exogenous NAM (1-0.5% in drinking water) was supplemented for 5 weeks and in the last 4 weeks moderate treadmill running was given to 5 mo and 28 mo old rats. The content of SIRT1 was not effected by NAM treatment alone. However, the activity of SIRT1, judged from the acetylated p53/p53 ratio, increased in both NAM treated age groups, suggesting beneficial effects of exogenous NAM. This was confirmed by the finding of increased PGC-1α and pCREB/CREB ratio in the gastrocnemius muscle of old but not young NAM treated animals. Our data suggest NAM administration can attenuate the aging process in skeletal muscle of rats, but NAM administration together with exercise training might be too great challenge to cope with in the old animals, since it leads to decreased levels of SIRT1.

Exercise-induced oxidative stress: past, present and future.

The existence of free radicals in living cells was first reported in 1954 and this important finding helped launch the field of free radical biology. However, the discovery that muscular exercise is associated with increased biomarkers of oxidative stress did not occur until 1978. Following the initial report that exercise promotes oxidative stress in humans, many studies have confirmed that prolonged or short-duration high intensity exercise results in increased radical production in active skeletal muscles resulting in the formation of oxidized lipids and proteins in the working muscles. Since these early descriptive studies, the investigation of radicals and redox biology related to exercise and skeletal muscle has grown as a discipline and the importance of this research in the biomedical sciences is widely recognized. This review will briefly summarize the history of research in exercise-induced oxidative stress and will discuss the major paradigm shifts that the field has undergone and continues to experience. We conclude with a discussion of future directions in the hope of stimulating additional research in this important field.

8-oxoguanine DNA glycosylase-1 augments proinflammatory gene expression by facilitating the recruitment of site-specific transcription factors.

Among the insidious DNA base lesions, 8-oxo-7,8-dihydroguanine (8-oxoG) is one of the most abundant, a lesion that arises through the attack by reactive oxygen species on guanine, especially when located in cis-regulatory elements. 8-oxoG is repaired by the 8-oxoguanine glycosylase 1 (OGG1)-initiated DNA base excision repair pathway. In this study, we investigated whether 8-oxoG repair by OGG1 in promoter regions is compatible with a prompt gene expression and a host innate immune response. For this purpose, we used a mouse model of airway inflammation, supplemented with cell cultures, chromatin immunoprecipitation, small interfering RNA knockdown, real-time PCR, and comet and reporter transcription assays. Our data show that exposure of cells to TNF-α altered cellular redox, increased the 8-oxoG level in DNA, recruited OGG1 to promoter sequences, and transiently inhibited base excision repair of 8-oxoG. Promoter-associated OGG1 then enhanced NF-κB/RelA binding to cis-elements and facilitated recruitment of specificity protein 1, transcription initiation factor II-D, and p-RNA polymerase II, resulting in the rapid expression of chemokines/cytokines and inflammatory cell accumulation in mouse airways. Small interfering RNA depletion of OGG1 or prevention of guanine oxidation significantly decreased TNF-α-induced inflammatory responses. Taken together, these results show that nonproductive binding of OGG1 to 8-oxoG in promoter sequences could be an epigenetic mechanism to modulate gene expression for a prompt innate immune response.