Do blood cells mimic gene expression profile alterations known to occur in muscular adaptation to endurance training ?

Mechanically demanding eccentric exercise increases nuclear factor erythroid 2-related factor 2 activity in human peripheral blood mononuclear cells

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Mitochondrial Mass of Naïve T Cells Is Associated with Aerobic Fitness and Energy Expenditure of Active and Inactive Adults

PURPOSE

Chronic exercise training is known to induce metabolic changes, but whether these adaptations extend to lymphocytes and how this may affect immune function remains largely unknown. This study was conducted to determine the extent to which mitochondrial characteristics of naïve T cells differ according to fitness status and to further examine the energy production pathways of cells from aerobically trained and inactive participants.

METHODS

Blood was collected from 30 aerobically active (>6 h·wk -1 ) or inactive (<90 min·wk -1 ) men and women. Naïve T cell mitochondrial mass, membrane potential, and biogenesis were assessed with flow cytometry. Participants completed a treadmill maximal oxygen consumption (V̇O 2peak ) test and wore a physical activity monitor for 1 wk. In a subset of participants, naïve CD8 + T cell activation-induced glycolytic and mitochondrial ATP production was measured.

RESULTS

Active participants exhibited 16.7% more naïve CD8 + T cell mitochondrial mass ( P = 0.046), 34% greater daily energy expenditure ( P < 0.001), and 39.6% higher relative V̇O 2peak ( P < 0.001), along with 33.9% lower relative body fatness ( P < 0.001). Among all participants, naïve CD8 + T cell mitochondrial mass was correlated with estimated energy expenditure ( r = 0.36, P = 0.048) and V̇O 2peak ( r = 0.47, P = 0.009). There were no significant differences in ATP production, mitochondrial biogenesis, or mitochondrial membrane potential between active and inactive groups.

CONCLUSIONS

This is the first study to examine the effects of aerobic exercise training status on metabolic parameters within human naïve T cells. Findings suggest that mitochondrial adaptations in certain immune cell types are positively associated with aerobic fitness and energy expenditure. This study provides a foundation for future development of prophylactic and therapeutic interventions targeting specific immune cell subsets to improve the immune response and overall health.

The effect of whole-body cryostimulation on body composition and leukocyte expression of HSPA1A, HSPB1, and CRP in obese men

In recent years, the prevalence of obesity has increased dramatically and has become a 21st century epidemic. Obesity is associated with the development of many diseases, and therefore treatments that can reduce body mass are actively sought. The aim of this study was to examine the effect of 20 cryostimulation sessions on body composition in obese/high body mass (HBM, n = 12) males and normal body mass (NBM, n = 9) controls. The HBM group had a mean age = 29.08 ± 4.19 years, body fat percentage = 32.08 ± 6.16%, body mass index = 36.23 ± 8.13 kg/m²) and NBM group had a mean age = 22.00 ± 2.45 years, body fat percentage = 12.14 ± 4.93%, body mass index = 23.58 ± 2.00 kg/m². Kilocalorie intake was similar for both groups. All participants received 20 sessions of systemic cryostimulation at -120°C for 2-3 min in a cryochamber. Blood samples were collected before the first session, 1 h after the 10th session, and 1 h after the 20th cryostimulation session. C-reactive protein (CRP) plasma concentrations, and expression of the heat shock protein genes (HSPA1A, HSPB1) and CRP mRNA in leukocytes were evaluated after 10 and 20 cryostimulation sessions. In both groups, 20 sessions were associated with a significant decrease in body mass, fat mass and the percentage of body fat. CRP concentrations were significantly higher in obese people before the first session and after 10 treatments, but not at the end of study. Expression of HSPA1A and HSPB1 mRNA gradually decreased with the number of cryostimulation sessions. A significant difference in HSPA1A expression was found after 20 sessions (NBM > HBM) and for HSPB1 at baseline and after 20 sessions (HBM > NBM). Our results show that cryostimulation influences body composition and that cryostimulation-induced HSP genes expression depends on the number of cryosessions and baseline body mass, and is differentially altered in HBM individuals. Further research on the interaction between body mass and cold adaptation is warranted.

Alleviation of Toxicity Caused by Overactivation of Pparα through Pparα-Inducible miR-181a2

Widely varied compounds, including certain plasticizers, hypolipidemic drugs (e.g., ciprofibrate, fenofibrate, WY-14643, and clofibrate), agrochemicals, and environmental pollutants, are peroxisome proliferators (PPs). Appropriate dose of PPs causes a moderate increase in the number and size of peroxisomes and the expression of genes encoding peroxisomal lipid-metabolizing enzymes. However, high-dose PPs cause varied harmful effects. Chronic administration of PPs to mice and rats results in hepatomegaly and ultimately carcinogenesis. Nuclear receptor protein peroxisome proliferator-activated receptor-α (Pparα) was shown to be required for this process. However, biological adaptations to minimize this risk are poorly understood. In this study, we found that miR-181a2 expression was induced by the Pparα agonist WY-14643. Moreover, exogenous expression of miR-181a-5p dramatically alleviated the cell toxicity caused by overactivation of Pparα. Further studies showed that miR-181a-5p directly targeted the Pparα 3′ untranslated region and depressed the Pparα protein level. This study identified a feedback loop between miR-181a-5p and Pparα, which allows biological systems to approach a balance when Pparα is overactivated.

Effect of Lower and Upper Body High Intensity Training on Genes Associated with Cellular Stress Response

This study aimed to compare the effect of upper and lower body high intensity exercise (HIE) on select gene expression in athletes. Fourteen elite male artistic gymnasts (age 20.9 ± 2.6 years; weight 68.6 ± 7.2 kg; fat free mass 63.6 ± 6.7 kg; height 1.70 ± 0.04 m) performed lower and upper body 30 s Wingate Tests (WAnTs) before and after eight weeks of specific HIIT. Two milliliters of blood was collected before and after (5, 30 min, resp.) lower and upper body WAnTs, and select gene expression was determined by PCR. Eight weeks of HIIT caused a significant increase in maximal power (722 to 751 Wat), relative peak power in the lower body WAnTs (10.1 to 11 W/kg), mean power (444 to 464 W), and relative mean power (6.5 to 6.8 W/kg). No significant differences in lower versus upper body gene expression were detected after HIIT, and a significant decrease in the IL6/IL10 ratio was observed after lower (−2^∧0.57 p = 0.0019) and upper (−2^∧0.5 p = 0.03) WAnTs following eight weeks of HIIT. It is hypothesized that a similar adaptive response to exercise may be obtained by lower and upper body exercise.

Gene expression is differentially regulated in skeletal muscle and circulating immune cells in response to an acute bout of high-load strength exercise

Background

High-intensity exercise induces many metabolic responses. In is unknown whether the response in the peripheral blood mononuclear cells (PBMCs) reflects the response in skeletal muscle and whether mRNA expression after exercise can be modulated by nutritional intake.

The aims were to (i) investigate the effect of dairy proteins on acute responses to exercise in skeletal muscle and PBMCs measuring gene expression and (ii) compare this response in young and older subjects.

Methods

We performed two separate studies in young (20–40 years) and older subjects (≥70 years). Subjects were randomly allocated to a milk group or a whey group. Supplements were provided immediately after a standardized exercise session. We measured mRNA expression of selected genes after a standardized breakfast and 60/120 min after finishing the exercise, using RT-qPCR.

Results

We observed no significant differences in mRNA expression between the milk and the whey group; thus, we merged both groups for further analysis. The mRNA expression of IL6, TNF, and CCL2 in skeletal muscle increased significantly after exercise compared with smaller or no increase, in mRNA expression in PBMCs in all participants. The mRNA expression of IL1RN, IL8, and IL10 increased significantly in skeletal muscle and PBMCs. Some mRNA transcripts were differently regulated in older compared to younger participants in PBMCs.

Conclusions

An acute bout of heavy-load strength exercise, followed by protein supplementation, caused overlapping, but also unique, responses in skeletal muscle and PBMCs, suggesting tissue-specific functions in response to exercise. However, no different effects of the different protein supplements were observed. Altered mRNA expressions in PBMCs of older participants may affect regenerative mechanisms.

Electronic supplementary material

The online version of this article (doi:10.1186/s12263-017-0556-4) contains supplementary material, which is available to authorized users.

Cellular Stress Response Gene Expression During Upper and Lower Body High Intensity Exercises

Objectives

The aim was to compare the effect of upper and lower body high-intensity exercise on chosen genes expression in athletes and non-athletes.

Method

Fourteen elite male artistic gymnasts (EAG) aged 20.6 ± 3.3 years and 14 physically active men (PAM) aged 19.9 ± 1.0 years performed lower and upper body 30 s Wingate Tests. Blood samples were collected before, 5 and 30 minutes after each effort to assess gene expression via PCR.

Results

Significantly higher mechanical parameters after lower body exercise was observed in both groups, for relative power (8.7 ± 1.2 W/kg in gymnasts, 7.2 ± 1.2 W/kg in controls, p = 0.01) and mean power (6.7 ± 0.7 W/kg in gymnasts, 5.4 ± 0.8 W/kg in controls, p = 0.01). No differences in lower versus upper body gene expression were detected for all tested genes as well as between gymnasts and physical active man. For IL-6 m-RNA time-dependent effect was observed.

Conclusions

Because of no significant differences in expression of genes associated with cellular stress response the similar adaptive effect to exercise may be obtained so by lower and upper body exercise.

Immune adaptation to chronic intense exercise training: new microarray evidence

BACKGROUND

Endurance exercise training, especially the high-intensity training, exhibits a strong influence on the immune system. However, the mechanisms underpinning the immune-regulatory effect of exercise remain unclear. Consequently, we chose to investigate the alterations in the transcriptional profile of blood leukocytes in young endurance athletes as compared with healthy sedentary controls, using Affymetrix human gene 1.1 ST array.

RESULTS

Group differences in the transcriptome were analyzed using Intensity-based Hierarchical Bayes method followed by a Logistic Regression-based gene set enrichment method. We identified 72 significant transcripts differentially expressed in the leukocyte transcriptome of young endurance athletes as compared with non-athlete controls with a false discovery rate (FDR) < 0.05, comprising mainly the genes encoding ribosomal proteins and the genes involved in mitochondrial oxidative phosphorylation. Gene set enrichment analysis identified three major gene set clusters: two were up-regulated in athletes including gene translation and ribosomal protein production, and mitochondria oxidative phosphorylation and biogenesis; one gene set cluster identified as transcriptionally downregulated in athletes was related to inflammation and immune activity.

CONCLUSION

Our data indicates that in young healthy individuals, intense endurance exercise training (exemplifed by athletic training) can chronically induce transcriptional changes in the peripheral blood leukocytes, upregulating genes related to protein production and mitochondrial energetics, and downregulating genes involved in inflammatory response. The findings of the study also provide support for the notion that peripheral blood can be used as a surrogate tissue to study the systemic effect of exercise training.

Exercise-induced Nrf2-signaling is impaired in aging

PURPOSE

The transcription factor nuclear erythroid-2 like factor-2 (Nrf2) is the master regulator of antioxidant defense. Data from animal studies suggest exercise elicits significant increases in Nrf2 signaling, and that signaling is impaired with aging resulting in decreased induction of phase II detoxifying enzymes and greater susceptibility to oxidative damage. We have previously shown that older adults have lower resistance to an oxidative challenge as compared to young, and that this response is modified with physical fitness and phytonutrient intervention. We hypothesized that a single bout of submaximal exercise would elicit increased nuclear accumulation of Nrf2, and that this response to exercise would be attenuated with aging.

METHODS

Nrf2 signaling in response to 30-min cycling at 70% VO2max was compared in young (23±1y, n=10) and older (63±1, n=10) men. Blood was collected at six time points; pre-exercise, and 10min, 30min, 1h, 4h, and 24h post-exercise. Nrf2 signaling was determined in peripheral blood mononuclear cells by measuring protein expression by western blot of Nrf2 in whole cell and nuclear fractions, and whole cell SOD1, and HMOX, as well as gene expression (RT-PCR) of downstream Nrf2-ARE antioxidants SOD1, HMOX, and NQO1.

RESULTS

Baseline differences in protein expression did not differ between groups. The exercise trial elicited significant increase in whole cell Nrf2 (P=0.003) for both young and older groups. Nuclear Nrf2 levels were increased significantly in the young but not older group (P=0.031). Exercise elicited significant increases in gene expression of HMOX1 and NQO1 in the young (P=0.006, and P=0.055, respectively) whereas gene expression in the older adults was repressed. There were no significant differences in SOD1 or HMOX1 protein expression.

CONCLUSION

These findings indicate a single session of submaximal aerobic exercise is sufficient to activate Nrf2 at the whole cell level in both young and older adults, but that nuclear import is impaired with aging. Additionally we have shown repressed gene expression of downstream antioxidant targets of Nrf2 in older adults. Together these translational data demonstrate for the first time the attenuation of Nrf2 activity in response to exercise in older adults.

Vitamin C, A and E supplementation decreases the expression of HSPA1A and HSPB1 genes in the leukocytes of young polish figure skaters during a 10-day training camp

Background

Overexpression of HSPA1A and HSPB1 has been shown to indicate stress and the degradation of damaged proteins. Therefore, the expression of these genes is often evaluated during exercise. Vitamin supplementation in young athletes may affect the expression of these genes, and help to maintain health and improve the effects of training.

Methods

Fourteen top junior female athletes (age 14–15y ± 0.3 SD, body mass 51 kg ± 5 SD, and BMI of 20.15 ± 0.9 SD, time in professional training 8.5 y ± 0.5 SD) attended a conditioning camp that included meals planned by a team dietitian. To examine the effects of vitamin supplementation on antioxidant status we supplemented the athletes with either vitamin A (16 ug/kg/day), vitamin C (8 mg/kg/day) and vitamin E (1 mg/kg/day) or an inert placebo. Blood samples were taken before and after (12 h post) the camp to assess the relative expression of HSPA1A and HSPB1 mRNA in leukocytes via quantitative reverse transcription polymerase chain reaction (qRT-PCR).

Results

Overall, participants trained ~135 min daily (1345 min total). No statistically significant differences in HSPA1A and HSPB1 expression were observed between the groups before the camp. In the unsupplemented group, there was a non-statistically significant increase in HSPA1A expression (100% change) and a significant increase (37% change, p < 0.05) in HSPB1 expression over the study period. The supplemented group experienced a significant decrease in HSPA1A (40% change, p = 0.01) and HSPB1 (25% change p = 0.03) expression over the study period.

Conclusion

Our results indicate that supplementation with antioxidant vitamins decreases HSPA1A and HSPB1 mRNA expression in leukocytes, and thereby may reduce exercise-induced stress in young athletes, not only during training, but also in sports competitions.

Expression microarray as a tool to identify differentially expressed genes in horses suffering from inflammatory airway disease

BACKGROUND

Inflammatory airway disease (IAD) affects performance and well-being of horses. Diagnosis is primarily reached by bronchoalveolar lavage (BAL) cytology which is invasive and requires sedation.

OBJECTIVES

The purpose of this study was to identify differential gene expression in peripheral blood of horses with IAD using species-specific expression microarrays.

METHODS

Equine gene expression microarrays were used to investigate global mRNA expression in circulating leukocytes from healthy, IAD-affected, and low-performing Standardbred and endurance horses.

RESULTS

Nine genes in Standardbred and 61 genes in endurance horses were significantly differentially regulated (P < .001). These genes were related to inflammation (eg, ALOX15B, PLA2G12B, and PENK), oxidant/antioxidant balance (eg, DUOXA2 and GSTO1-1), and stress (eg, V1aR, GRLF1, Homer-2, and MAOB). All these genes were up-regulated, except down-regulated Homer-2 and MAOB. DUOXA2, ALOX15B, PLA2G12B, MAOB, and GRLF1 expression was further validated by RT-qPCR. An increase in glutathione peroxidase (GPx) activity in heparinized whole blood of IAD-affected Standardbred (P = .0025) and endurance horses (P = .0028) also suggests a deregulation of the oxidant/antioxidant balance. There was good correlation (r = .7354) between BAL neutrophil percentage and whole blood GPx activity in all horses.

CONCLUSIONS

This study showed that circulating blood cell gene expression reflects inflammatory responses in tissues. Whether any of the genes have potential for diagnostic applications in the future remains to be investigated. Although not specific for IAD, whole blood GPx activity appears to be correlated with BAL neutrophil percentage. This finding should be further assessed by testing a larger number of horses.

PBMCs express a transcriptome signature predictor of oxygen uptake responsiveness to endurance exercise training in men

Peripheral blood cells are an accessible environment in which to visualize exercise-induced alterations in global gene expression patterns. We aimed to identify a peripheral blood mononuclear cell (PBMC) signature represented by alterations in gene expression, in response to a standardized endurance exercise training protocol. In addition, we searched for molecular classifiers of the variability in oxygen uptake (V̇o2). Healthy untrained policemen recruits (n = 13, 25 ± 3 yr) were selected. Peak V̇o2 (measured by cardiopulmonary exercise testing) and total RNA from PBMCs were obtained before and after 18 wk of running endurance training (3 times/wk, 60 min). Total RNA was used for whole genome expression analysis using Affymetrix GeneChip Human Gene 1.0 ST. Data were normalized by the robust multiarray average algorithm. Principal component analysis was used to perform correlations between baseline gene expression and V̇o2peak. A set of 211 transcripts was differentially expressed (ANOVA, P < 0.05 and fold change > 1.3). Functional enrichment analysis revealed that transcripts were mainly related to immune function, cell cycle processes, development, and growth. Baseline expression of 98 and 53 transcripts was associated with the absolute and relative V̇o2peak response, respectively, with a strong correlation (r > 0.75, P < 0.01), and this panel was able to classify the 13 individuals according to their potential to improve oxygen uptake. A subset of 10 transcripts represented these signatures to a similar extent. PBMCs reveal a transcriptional signature responsive to endurance training. Additionally, a baseline transcriptional signature was associated with changes in V̇o2peak. Results might illustrate the possibility of obtaining molecular classifiers of endurance capacity changes through a minimally invasive blood sampling procedure.

Physiological functions of peroxisome proliferator-activated receptor β

The peroxisome proliferator-activated receptors, PPARα, PPARβ, and PPARγ, are a family of transcription factors activated by a diversity of molecules including fatty acids and fatty acid metabolites. PPARs regulate the transcription of a large variety of genes implicated in metabolism, inflammation, proliferation, and differentiation in different cell types. These transcriptional regulations involve both direct transactivation and interaction with other transcriptional regulatory pathways. The functions of PPARα and PPARγ have been extensively documented mainly because these isoforms are activated by molecules clinically used as hypolipidemic and antidiabetic compounds. The physiological functions of PPARβ remained for a while less investigated, but the finding that specific synthetic agonists exert beneficial actions in obese subjects uplifted the studies aimed to elucidate the roles of this PPAR isoform. Intensive work based on pharmacological and genetic approaches and on the use of both in vitro and in vivo models has considerably improved our knowledge on the physiological roles of PPARβ in various cell types. This review will summarize the accumulated evidence for the implication of PPARβ in the regulation of development, metabolism, and inflammation in several tissues, including skeletal muscle, heart, skin, and intestine. Some of these findings indicate that pharmacological activation of PPARβ could be envisioned as a therapeutic option for the correction of metabolic disorders and a variety of inflammatory conditions. However, other experimental data suggesting that activation of PPARβ could result in serious adverse effects, such as carcinogenesis and psoriasis, raise concerns about the clinical use of potent PPARβ agonists.

Whole blood transcriptomics and urinary metabolomics to define adaptive biochemical pathways of high-intensity exercise in 50-60 year old masters athletes

Exercise is beneficial for a variety of age-related disorders. However, the molecular mechanisms mediating the beneficial adaptations to exercise in older adults are not well understood. The aim of the current study was to utilize a dual approach to characterize the genetic and metabolic adaptive pathways altered by exercise in veteran athletes and age-matched untrained individuals. Two groups of 50–60 year old males: competitive cyclists (athletes, n = 9; VO_2peak 59.1±5.2 ml·kg⁻¹·min⁻¹; peak aerobic power 383±39 W) and untrained, minimally active individuals (controls, n = 8; VO_2peak 35.9±9.7 ml·kg⁻¹·min⁻¹; peak aerobic power 230±57 W) were examined. All participants completed an acute bout of submaximal endurance exercise, and blood and urine samples pre- and post-exercise were analyzed for gene expression and metabolic changes utilizing genome-wide DNA microarray analysis and NMR spectroscopy-based metabolomics, respectively. Our results indicate distinct differences in gene and metabolite expression involving energy metabolism, lipids, insulin signaling and cardiovascular function between the two groups. These findings may lead to new insights into beneficial signaling pathways of healthy aging and help identify surrogate markers for monitoring exercise and training load.

A combination of (ω-3) polyunsaturated fatty acids, polyphenols and L-carnitine reduces the plasma lipid levels and increases the expression of genes involved in fatty acid oxidation in human peripheral blood mononuclear cells and HepG2 cells

BACKGROUND

Hyperlipidemia and obesity are associated with metabolic syndrome and increased risk in developing diabetes and cardiovascular disease. Nutritional supplements, e.g. L-carnitine and polyunsaturated fatty acids (PUFAs), exert lipid-lowering effects. Hence, the hypothesis that dietetic intervention reduces plasma lipid levels and metabolic enzymes in overweight hyperlipidemic subjects was tested.

SUBJECTS AND METHODS

In a prospective placebo-controlled double-blind study in 22 moderately hyperlipidemic obese humans consuming low-fat yoghurt enriched with a combination of low-dose PUFAs, polyphenols and L-carnitine (PPC) twice a day for 12 weeks were compared to 20 matching participants ingesting low-fat yoghurt. The effects on plasma lipids and expression of enzymes involved in regulation of fatty acid oxidation in peripheral blood mononuclear cells (PBMCs) and HepG2 cells were evaluated.

RESULTS

PPC consumption led to significantly reduced plasma free fatty acid (-29%) and triglyceride (-24%) concentrations (each p < 0.05). PPC application increased significantly peroxisome proliferator-activated receptor α (PPARα) mRNA abundances and those of PPARα target genes (carnitine palmitoyltransferases-1, CPT1A and CPT1B, carnitine acetyltransferase and organic cation transporter 2; each p < 0.05) in PBMCs. In controls, plasma lipid levels and PBMC gene expression did not change. These findings were substantiated by the results of cell culture experiments in HepG2 cells.

CONCLUSION

Supplementation of PPC had marked lipid-lowering effects and PBMC gene expression profiles seemed to reflect nutrition-related metabolic changes.

Abnormally low serum acylcarnitine levels in narcolepsy patients

BACKGROUND

Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness, cataplexy, and REM sleep abnormalities. A genome-wide association study identified a novel narcolepsy-related single nucleotide polymorphism (SNP), rs5770917, which is located adjacent to CPT1B (carnitine palmitoyltransferase 1B). In this study, we analyzed the CPT1B expression level and measured the carnitine fractions in blood samples obtained from narcolepsy patients and control subjects to test the hypothesis that fatty acid β-oxidation is altered in narcolepsy.

METHODOLOGY AND RESULTS

We measured CPT1B mRNA expression in white blood cells of 38 narcolepsy patients and 56 healthy control subjects. The serum carnitine fractions (total carnitine, free carnitine, and acylcarnitine) were measured in the 38 narcolepsy patients and in 30 of 56 control subjects. Stepwise multiple regression analysis revealed that the risk allele (C) for SNP rs5770917 was significantly associated with decreased CPT1B mRNA expression (P = 1.0 × 10(-9)), and the CPT1B expression was higher in the narcolepsy patients than in the controls (P = 0.005). The acylcarnitine levels were abnormally low in 21% of the narcolepsy patients while those of all the controls were within the normal range. Stepwise multiple regression analysis using the dichotomous variable for acylcarnitine (normal or abnormal) as an objective variable revealed that the diagnosis of narcolepsy but not CPT1B expression level and BMI was associated with abnormally low acylcarnitine levels (P = 0.006).

CONCLUSIONS

Our results indicate that multiple factors are involved in the regulation of serum acylcarnitine levels. Abnormally low levels of acylcarnitine observed in narcolepsy suggest dysfunctional fatty acid β-oxidation pathway.

Exercise-induced up-regulation of MMP-1 and IL-8 genes in endurance horses

Background

The stress response is a critical factor in the training of equine athletes; it is important for performance and for protection of the animal against physio-pathological disorders.

In this study, the molecular mechanisms involved in the response to acute and strenuous exercise were investigated using peripheral blood mononuclear cells (PBMCs).

Results

Quantitative real-time PCR (qRT-PCR) was used to detect modifications in transcription levels of the genes for matrix metalloproteinase-1 (MMP-1) and interleukin 8 (IL-8), which were derived from previous genome-wide expression analysis. Significant up-regulation of these two genes was found in 10 horses that had completed a race of 90–120 km in a time-course experimental design.

Conclusion

These results suggest that MMP-1 and IL-8 are both involved in the exercise-induced stress response, and this represents a starting point from which to understand the adaptive responses to this phenomenon.

Effect of intermittent hypoxic training on HIF gene expression in human skeletal muscle and leukocytes

Intermittent hypoxic exposure with exercise training is based on the assumption that brief exposure to hypoxia is sufficient to induce beneficial muscular adaptations mediated via hypoxia-inducible transcription factors (HIF). We previously demonstrated (Mounier et al. Med Sci Sports Exerc 38:1410-1417, 2006) that leukocytes respond to hypoxia with a marked inter-individual variability in HIF-1alpha mRNA. This study compared the effects of 3 weeks of intermittent hypoxic training on hif gene expression in both skeletal muscle and leukocytes. Male endurance athletes (n = 19) were divided into an Intermittent Hypoxic Exposure group (IHE) and a Normoxic Training group (NT) with each group following a similar 3-week exercise training program. After training, the amount of HIF-1alpha mRNA in muscle decreased only in IHE group (-24.7%, P < 0.05) whereas it remained unchanged in leukocytes in both groups. The levels of vEGF(121) and vEGF(165) mRNA in skeletal muscle increased significantly after training only in the NT group (+82.5%, P < 0.05 for vEGF(121); +41.2%, P < 0.05 for vEGF(165)). In leukocytes, only the IHE group showed a significant change in vEGF(165) (-28.2%, P < 0.05). The significant decrease in HIF-1alpha mRNA in skeletal muscle after hypoxic training suggests that transcriptional and post-transcriptional regulations of the hif-1alpha gene are different in muscle and leukocytes.

The carnitine acetyltransferase gene (CRAT): a characterization of porcine transcripts with insights into the 5'-end variants of mammalian transcripts and their possible sub-cellular localization

Carnitine acetyltransferase (CRAT) is an important enzyme for energy homeostasis and fat metabolism. We characterized the predicted full length cDNA sequence of the porcine CRAT gene. Its structure is very similar to that in humans with respect to the size and organization of the 14 exons. We demonstrated the existence of a porcine alternative transcript resulting from a partial intron-retention at the 5’ end of exon 2. To perform a comparison of the 5’ end variants of the mammalian CRAT gene, we analyzed the Genbank data, and here we propose a new 5’ variant for dog, rat and mouse. In contrast to other mammals where this variant encodes a shorter protein (−21 aa in human, mouse and rat, and −14 aa in dog), the pig variant encodes for a longer protein (+18 aa). In all mammalian species, variant 1 has a high probability of a preferential mitochondrial sub-cellular localization. Nevertheless, it is not evident, in particular in porcine and dog species, that the second variant is associated with a different sub-cellular specificity.

The peripheral-blood transcriptome: new insights into disease and risk assessment

Future personalized medicine strategies for assessing an individual's health require, ideally, a noninvasive system that is capable of integrating numerous interactive factors, including gender, age, genetics, behavior, environment and comorbidities. Several microarray-based methods developed to meet this goal are currently under investigation. However, most rely on tissue biopsies, which are not readily available or accessible. As an alternative, several recent studies have investigated the use of human peripheral blood cells as surrogate biopsy material. Such studies are based on the assumption that molecular profiling of circulating blood might reflect physiological and pathological events occurring in different tissues of the body. This has led to the development of novel methods for identifying and monitoring blood biomarkers to probe an individual's health status. Here, we discuss the rationale and clinical potential of profiling the peripheral-blood transcriptome.

Exercise affects the gene expression profiles of human white blood cells

White blood cells (WBCs) express tens of thousands of genes, whose expression levels are modified by genetic and external factors. The purpose of the present study was to investigate the effects of acute exercise on gene expression profiles (GEPs) of WBCs and to identify suitable genes that may serve as surrogate markers for monitoring exercise and training load. Five male participants performed an exhaustive treadmill test (ET) at 80% of their maximal O2uptake (V̇o2 max) and a moderate treadmill test (MT) at 60% V̇o2 maxfor exactly the same time ∼2 wk later. WBCs were isolated by the erythrocyte lysis method. GEPs were measured using the Affymetrix GeneChip technology. After scaling, normalization, and filtering, groupwise comparisons of gene expression intensities were performed, and several measurements were validated by real-time PCR. We found 450 genes upregulated and 150 downregulated (>1.5-fold change; ANOVA with Benjamini-Hochberg correction, P < 0.05) after ET that were closely associated with the gene ontology lists “response to stress” and “inflammatory response”. Analysis of mean expression levels after MT showed that the extent of up- and downregulation was workload dependent. The genes for the stress (heat shock) proteins HSPA1A and HSPH1 and for the matrix metalloproteinase MMP-9 showed the most prominent increases, whereas the YES1 oncogene (YES1) and CD160 (BY55) were most strongly reduced. Despite different methodological approaches used, the consistency of our results with the expression data of another study (Connolly PH, Caiozzo VJ, Zaldivar F, Nemet D, Larson J, Hung SP, Heck JD, Hatfield GW, Cooper DM. J Appl Physiol 97: 1461–1469, 2004) suggests that expression fingerprints are useful tools for monitoring exercise and training loads and thereby help to avoid training-associated health risks.

Does mRNA level of microsomal carnitine palmitoyltransferase predict yield of peripheral blood stem cell apheresis?

Transplantation of autologous hematopoietic stem cells is a well established therapeutic procedure. Despite advances in efficacy of the stem cell mobilization and apheresis process until now a predictive factor for the expected stem cell yield before initiation of mobilization therapy could not be identified. The main objective of our study was to evaluate alterations in enzymes involved in fatty acid metabolism on the level of gene expression in mononuclear cells, as changes in relative mRNA levels of these enzymes could represent the hematopoietic regenerative potential. Data of 23 consecutive patients with different lymphoid malignancies undergoing stem cell mobilization were analyzed. Our results show that mRNA levels of microsomal carnitine palmitoyltransferase in peripheral blood mononuclear cells quantified before application of mobilization therapy correlate positively with the amount of CD34 positive cells in peripheral blood before first apheresis, in the first apheresis product and in the total harvest outcome. The association of enzymes involved in fatty acid metabolism with hematoopoiesis was further confirmed in healthy subjects on altitude-adaptation training and in proliferating or differentiating HL60 cells. This gives evidence for a possible predictive value of such analyzes though further data of a larger sample are to be collected to confirm our observations.

Effects of doxorubicin-containing chemotherapy and a combination with l-carnitine on oxidative metabolism in patients with non-Hodgkin lymphoma

PURPOSE

Chemotherapy regimens based on anthracycline (doxorubicin) are well established in lymphoma therapy. The purpose of this study was to examine the effects of L-carnitine with a view to reducing cytotoxic side-effects.

METHODS

20 patients were scheduled to receive 3 g L-carnitine before each chemotherapy cycle, followed by 1 g L-carnitine/day during the following 21 days, while 20 patients received a placebo (randomized controlled trial). The plasma lipid profile and relative mRNA levels of key enzymes of oxidative metabolism (carnitine acyltransferases) were measured at three points of time. In addition to the clinical parameters we used the mRNA of white blood cells to evaluate the toxic effects on cardiomyocytes.

RESULTS

In the present study no cardiotoxicity of anthracycline therapy was detected. Carnitine treated patients showed a rise in plasma carnitine which led to an increase of relative mRNA levels from CPT1A (liver isoform of carnitine palmitoyltransferase) and OCTN2 (carnitine transporter). Following chemotherapy, an activation of carnitine acyltransferases was associated with a stimulation of OCTN2 in both groups.

CONCLUSION

Biochemical and molecular analyses indicated a stimulation of oxidative metabolism in white blood cells through carnitine uptake.