Browsing by Subject "Gene expression."
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Effect of resistance exercise intensity on the expression of PGC-1alpha isoforms and the anabolic and catabolic signaling mediators, IGF-1 and myostatin, in human skeletal muscle.(2014-06-11) Schwarz, Neil Andrew.; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.Proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) is a protein mechanistically involved in skeletal muscle adaptations to exercise. Recently, novel isoforms of PGC-1α have been identified, one of which (PGC-1α4) may be important for the development of muscle hypertrophy and strength in response to resistance exercise. Studies are needed to elucidate the specific resistance exercise conditions for which mRNA expression of the various PGC-1α isoforms is stimulated, particularly in humans. The purpose of this study was to describe the mRNA expression of the PGC-1α isoforms, and genes potentially under their regulation, in response to two resistance exercise intensities. In a cross-over design, ten participants performed two separate testing sessions involving a lower-body resistance exercise component consisting of a lower-intensity (50% of 1-repetition maximum; 1-RM) protocol and a higher-intensity (80% of 1-RM) protocol of equal volumes. Muscle samples were obtained at baseline, 45-min post-exercise (PE), 3-hr PE, 24-hr PE, and 48-hr PE. From each muscle sample, mRNA expression of PGC-1α1, PGC-1α2, PGC-1α3, PGC-1α4, myostatin, insulin-like growth factor-1Ea (IGF-1Ea), mechano growth factor (MGF), myosin heavy chain (MHC) I, MHC IIa, MHC IIx, was determined. Two-way repeated-measures analyses of variance (ANOVA) were performed (p ≤ 0.05) with intensity and time as main effects. Significant main effects existed for time for all PGC-1α and MHC isoforms (p < .05). Compared with baseline, PGC-1α1 was decreased at 24-hr and 48-hr PE. Conversely, PGC-1α2, PGC-1α3, and PGC-1α4 mRNA expression increased in response to exercise, peaking at 3-hr PE. MHC I, IIa, and IIx mRNA expression decreased at all time points measured following exercise. A significant interaction between intensity and time for IGF-1Ea was observed (p < .05). For the higher-intensity session, IGF-1Ea was increased at 24-hr PE compared with baseline and the lower-intensity session at the same time point (p < .05). The results of this study demonstrate an effect of resistance exercise on the expression of the novel PGC-1α isoforms without influence of intensity. Future research should determine if resistance exercise alters the expression of these genes at the translational level and if these potential effects contribute to skeletal muscle training adaptations in humans.Item Gene expression profiling to understand the alterations in the monocyte compartment of pediatric systemic lupus erythematosus.(2008-06-11T17:41:33Z) Patel, Pinakeen Shankarbhai.; Pascual, Virginia.; Banchereau, Jacques.; Biomedical Studies.; Baylor University. Institute of Biomedical Studies.Blood monocytes from SLE patients display DC function, as they are able to induce the proliferation of allogeneic T cells. Furthermore, sera from SLE patients induce healthy monocytes to differentiate into DCs. This DC-inducing property is in part due to the presence of type-I IFNs in SLE sera, as well as other, yet uncharacterized factors. To understand these alterations, we performed a thorough phenotypic analysis and gene expression profiling of monocytes from children with active, newly diagnosed and untreated disease. Phenotypic analysis of freshly isolated SLE blood monocytes revealed a modest expansion of CD14highCD16+ cells and an otherwise lack of expression of molecules related to DC function. Further characterization of a fraction of SLE monocytes inducing allogeneic T cell proliferation revealed that upon contact with T cells, SLE monocytes secrete proinflammatory cytokines such as IL-1 and IL-6 and do upregulate expression of innate immunity receptors involved in DC differentiation and molecules responsible for antigen presentation. To recapitulate the initial events leading to monocyte differentiation in this disease, we studied the effects of SLE serum on healthy monocyte at the trasncriptional and protein levels. These studies revealed the upregulation of expression on these cells of chemokine receptor such as CX3CR1 and CCR7, which may lead to the migration of blood monocytes to inflammed tissues and/or secondary lymphoid organs respectively in vivo. There, contact with T cells would lead to the acquisition of antigen presenting function and skewing from tolerogenic to immunogenic responses.Item The recombinant expression of two pollen allergens using plant-viral and yeast expression systems.(2006-05-09T19:12:08Z) Moehnke, Marcie H.; Kearney, Christopher Michel, 1958-; Biomedical Studies.; Baylor University. Institute of Biomedical Studies.Allergic disease causes much distress within industrialized areas of the world, affecting approximately a quarter of the population in such areas. Current immunotherapy involves the administration of increasing concentrations of crude allergen extracts over a period of time, in an attempt to switch the individual's allergic response to that of a non-allergic individual. Such therapy is largely ineffective, especially for cedar hypersensitivity where only 30% of individuals respond after two years of weekly injections, and unwanted and sometimes life-threatening side effects can accompany specific immunotherapy. In an effort to increase its efficacy, as well as circumvent these negative side effects, recombinant DNA technology is being used to produce recombinant allergens that will take the place of crude allergen extracts found in immunotherapy injections. A main cause of allergic disease within south central Texas is pollen produced by mountain cedars, Juniperus ashei. In one study, I cloned a particular mountain cedar allergen, Jun a 3, into a tobacco mosaic virus vector under the regulation of a subgenomic promoter. Infectious viral transcripts were inoculated onto Nicotiana benthamiana plants, and recombinant Jun a 3 protein was detected within these plants at 21 days post-inoculation. The recombinant protein was able to bind anti-Jun a 3 IgG antibodies as well as IgE from mountain cedar allergic patient sera. A separate study also demonstrated the successful expression of recombinant Jun a 3, but in a yeast expression system. The Jun a 3 cDNA was cloned into a yeast expression vector and transformed into Pichia pastoris cells for expression. Western blotting and ELISA experiments confirmed the recombinant Jun a 3 produced by the yeast bound anti-Jun a 3 IgG antibodies and IgE from allergic patient sera. A third study utilized the tobacco mosaic virus-based plant expression system to produce the main Italian cypress allergen, Cup s 1, from Cupressus sempervirens. This recombinant allergen behaved very similarly to a native cross-reactive allergen in its binding to IgG antibodies and allergic patient sera.