Natural killers (NK) cells are unique innate immune cells that increase up to fivefold in the circulating blood with brief exercise and are known to play a key role in first-response defense against pathogens and cancer immunosurveillance. Whether exercise alters NK cell gene and microRNA (miRNA) expression is not known. Thirteen healthy men (20–29 yr old) performed ten 2-min bouts of cycle ergometer exercise at a constant work equivalent to an average of 77% of maximum O₂ consumption interspersed with 1-min rest. Blood was drawn before and immediately after the exercise challenge. NK cells were isolated from peripheral blood mononuclear cells using a negative magnetic cell separation method. We used Affymetrix U133+2.0 arrays for gene expression and Agilent Human miRNA V2 Microarray for miRNAs. A stringent statistical approach (false discovery rate < 0.05) was used to determine that exercise significantly altered the expression of 986 genes and 23 miRNAs. Using in silico analysis, we found exercise-related gene pathways where there was a high likelihood of gene-miRNA interactions. These pathways were predominantly associated with cancer and cell communication, including p53 signaling pathway, melanoma, glioma, prostate cancer, adherens junction, and focal adhesion. These data support the hypothesis that exercise affects the gene and miRNA expression pattern in the population of NK cells in the circulation and suggest mechanisms through which physical activity could alter health through the innate immune system.

Background

The ability to accurately measure patterns of gene expression is essential in studying gene function. The reverse transcription polymerase chain reaction (RT-PCR) has become the method of choice for the detection and measurement of RNA expression patterns in both cells and small quantities of tissue. Our previous results show that there is a significant production of primer-independent cDNA synthesis using a popular RNase H^- RT enzyme. A PCR product was amplified from RT reactions that were carried out without addition of RT-primer. This finding jeopardizes the accuracy of RT-PCR when analyzing RNA that is expressed in both orientations. Current literature findings suggest that naturally occurring antisense expression is widespread in the mammalian transcriptome and consists of both coding and non-coding regulatory RNA. The primary purpose of this present study was to investigate the occurrence of primer-independent cDNA synthesis and how it may influence the accuracy of detection of sense-antisense RNA pairs.

Results

Our findings on cellular RNA and in vitro synthesized RNA suggest that these products are likely the results of RNA self-priming to generate random cDNA products, which contributes to the loss of strand specificity. The use of RNase H⁺ RT enzyme and carrying the RT reaction at high temperature (50°C) greatly improved the strand specificity of the RT-PCR detection.

Conclusion

While RT PCR is a basic method used for the detection and quantification of RNA expression in cells, primer-independent cDNA synthesis can interfere with RT specificity, and may lead to misinterpretation of the results, especially when both sense and antisense RNA are expressed. For accurate interpretation of the results, it is essential to carry out the appropriate negative controls.

Physical activity can prevent and/or attenuate atherosclerosis, a disease clearly linked to inflammation. Paradoxically, even brief exercise induces a stress response and increases inflammatory cells like monocytes in the circulation. We hypothesized that exercise would regulate the expression of genes, gene pathways, and microRNAs in monocytes in a way that could limit pro-inflammatory function and drive monocytes to prevent, rather than contribute to, atherosclerosis. Twelve healthy men (22-30year old) performed ten 2-min bouts of cycle ergometer exercise at a constant work equivalent to an average of 82% of maximum O2 consumption interspersed with 1-min rest. Blood was drawn before and immediately after the exercise. Monocytes were isolated from peripheral blood mononuclear cells. Flow cytometry was used to identify monocyte subtypes. We used Affymetrix U133 + 2.0 arrays for gene expression and Agilent Human miRNA V2 Microarray for miRNAs. A stringent statistical approach (FDR <0.05) was used to determine that exercise significantly altered the expression of 894 annotated genes and 19 miRNAs. We found distinct gene alterations that were likely to direct monocytes in an anti-inflammatory, anti-atherogenic pathway, including the downregulation of monocyte TNF, TLR4, and CD36 genes and the upregulation of EREG and CXCR4. Exercise significantly altered a number of microRNAs that likely influence monocytes involvement in vascular health. Exercise leads to a novel genomic profile of circulating monocytes, which appears to promote cardiovascular health despite the overall stress response.

Introduction: Fitness can improve asthma management. However, children from disadvantaged and minority communities generally engage less in physical activity, and have increased obesity and asthma disease burden. The goal of this pilot study is to evaluate (1) the feasibility of an exercise intervention program in a school-based setting (attendance and fitness improvement) and (2) the effect of the intervention on fitness, asthma, and clinical outcomes in normal weight and overweight/obese children with asthma from low-SES population. Materials and Methods: Nineteen children, ages 6-13 years, from two elementary schools in Santa Ana, CA, a population with high percentage of Hispanic and low socioeconomic status, participated. Training sessions occurred at the schools during afterschool hours (3 sessions weekly × 4 months) and included mainly aerobic age-appropriate activities/games and a small component of muscle strength. Before and after the intervention, evaluations included pulmonary function testing, cardiopulmonary exercise testing (peak V ˙ O₂), assessments of habitual physical activity, body composition (DXA), asthma questionnaires, and blood (cardiometabolic risk factors). Results: Seventeen of 19 participants completed the study. Adherence to the program was 85%. Based on BMI %ile, 11 of the participants were overweight/obese and 8 were normal weight. Ten participants had persistent asthma and 9 children had intermittent asthma. Training was effective as peak V ˙ O₂ improved significantly (8.1%, SD ± 10.1). There was no significant change in BMI %ile but a significant improvement in lean body mass (1%, SD ± 2.0) and decrease in body fat (1.9%, SD ± 4.6). Asthma quality of life outcomes improved following the intervention in symptoms, emotional function, and overall. There was no change in asthma control or pulmonary function. Five of 10 participants with persistent asthma decreased their maintenance medications. Lipid levels did not change except HDL levels increased (46.1 ± 8.4 mg/dL to 49.5 ± 10.4 mg/dL, p = 0.04). Discussion: A school-based exercise intervention program designed specifically for children with asthma for a predominantly economically disadvantaged and minority population was feasible with good adherence to the program and substantial engagement from the schools, families and participants. The exercise intervention was effective with improvement in aerobic fitness, body composition, asthma quality of life, and lipid outcomes, setting the stage for a larger multicenter trial designed to study exercise as an adjunct medicine in children with asthma.