Kinesiology
Permanent URI for this communityhttp://hdl.handle.net/1903/2253
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Item Relationship between physical activity and telomere maintenance in peripheral blood mononucleocytes(2007-07-24) Ludlow, Andrew Todd; Roth, Stephen M; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The purpose of this study was to examine the relationship between exercise energy expenditure (EEE) and telomere length, telomerase activity, and hTERT genotype. Sixty-nine male (n = 34) and female (n = 35) participants 50-70 yr. were assessed for weekly EEE level using the Yale Physical Activity Survey. Subjects were grouped according to EEE. Telomere length and telomerase activity were measured in peripheral blood mononuclear cells (PBMCs). Relative telomere length was significantly higher in the Middle EEE group compared to both the low and high EEE groups (p<0.05). Telomerase activity was not different among the three EEE groups. The TT hTERT genotype had significantly greater telomerase enzyme activity than both the CT and CC genotypes (P = 0.013). In conclusion, moderate exercise energy expenditure levels may provide a protective effect on PBMC telomere length compared to both low and high EEE levels. hTERT genotype was associated with telomerase activity.Item NFKB1 Gene Promoter Polymorphism and Unidirectional Laminar Shear Stress: Implications for NF-kB Activation, eNOS Protein Expression and Endothelial Function(2006-06-04) Park, Joon Young; Brown, Michael D.; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Exercise stimulus can be defined as endothelial wall shear stress. In the endothelial cells, the nuclear factor-kappa B (NF-κB) is an important intracellular signaling molecule by which changes in wall shear stress, sensed by mechanosensors, are transduced into the nucleus to initiate downstream eNOS gene expression. Recently, a polymorphism in the promoter region of the gene encoding a p50/p105 NF-κB subunit, NFKB1, has been identified. The NFKB1 ATTG insertion (I) / deletion (D) (NFKB1 I/D) promoter polymorphism transcriptionally regulates NFKB1 gene expression. However, the functional significance of this polymorphism has not been elucidated in endothelial cells under LSS and in endothelial function in humans. Therefore, the purpose of this study was to investigate whether the NFKB1 I/D promoter polymorphism had functional genetic properties in human umbilical vein endothelial cells (HUVECs) under physiological levels of unidirectional laminar shear stress (LSS), and further, whether the polymorphism was associated with changes in endothelial function after endurance exercise training in pre- and stage I hypertensive individuals. The major findings of the present study were that 1) a protein present in HUVECs preferentially and specifically binds to the I allele promoter compare to the D allele; 2) the I allele had significantly higher promoter activity than the D allele; and accordingly, the II homozygote cells had higher p50/p105 NFKB1 protein levels than the DD homozygote cells; 3) the II homozygote cells showed a greater increase in eNOS protein levels than the DD homozygote cells under unidirectional LSS; and 4) the I-allele carrier group had a greater reactive hyperemic forearm blood flow response, a measure of endothelial function, before exercise training; however, the NFKB1 I/D polymorphism was not significantly associated with the differential changes in endothelial function following exercise training. These results have potential clinical implications for endothelial dysfunction that are related to the development and progression of atherosclerosis and cardiovascular disease. In addition, our findings provide insight into the molecular mechanisms involved in the intracellular signaling transduction process of eNOS gene expression and function of the NFKB1 gene promoter region.