Browsing by Subject "Genetic regulation."
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Item Design, optimization, and evaluation of conditionally active gene therapy vectors.(2008-06-09T11:51:54Z) Wood, David Rowe.; Ding, Jiahuan.; Biomedical Studies.; Baylor University. Institute of Biomedical Studies.It is the objective of this project to produce gene therapy vectors that are active and/or significantly up-regulated due to specific physiological conditions. The significance of such constructs is that it imparts a greater degree of control in the implementation of gene therapy. In general, it is desirable for a gene therapy vector to be active only when and where it is needed. The majority of gene therapy research to date has focused primarily on obtaining expression levels high enough to elicit a therapeutic response, as well as, distributing the vector to enough tissues to provide a corrective effect to the disorder being addressed. However, simply having a gene adequately delivered to enough cells to treat disease and having the gene product be produced in sufficient amounts to have a therapeutic effect cannot be the end of the story. Not unlike genes found naturally in the body, artificially delivered genes also need to be regulated. The construction of such vectors could prove useful for the treatment of disorders; such as Coronary Artery Disease (CAD) or even Cardiomyopathy, that occur in a specific tissue type or that are associated with an abnormal physiological state, such as hypoxia. Our vector constructs are a small step towards this ultimate goal. In this study, we present data on DNA vectors that were designed, constructed and evaluated in vitro and in vivo; both qualitatively and quantitatively. We report success in the creation of vectors/plasmids that are primarily cardiac tissue specific (pMHCI, pMHCII), vectors that are regulated by cellular oxygen levels (pHAL, pHAM), and even some success in combining the two (pHMHC).Item Effects of concentric and eccentric muscle contractions on IL-6 signaling in human skeletal muscle and downstream regulation of HSP-72 gene expression : Is IL-6 signaling involved in exercise-induced cytoprotection?(2009-04-01T16:08:10Z) Harvey, Travis.; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.Purpose: To determine the effects of concentric and eccentric muscle contractions on IL-6 signaling and its possible downstream regulation of HSP-72 expression in human skeletal muscle, and whether contraction-induced IL-6 expression may initiate a cytoprotective mechanism in the muscle by activating HSP-72 and HSP-27. Methods: Using a cross-over design, 10 recreationally active males (20.60 ± 2.80 yrs; 77.35 ± 12.79 kg) participated in 2 separate bouts of 10 sets of 10 unilateral isokinetic knee extensions at 30°/sec. Each subject performed one concentric (CON) and one eccentric (ECC) bout, with strength assessed 5 days prior to and at 24 and 48 hr after the bout. Muscle soreness and blood samples were sampled immediately before exercise (PRE), immediately post-exercise (POST), and at 2, 6, 24, and 48 hr after exercise for serum levels of CK, IL-6, IL-1β, and TNF-α. Muscle biopsies were obtained at PRE, POST, and at 2 and 6 hr post-exercise and assessed for protein levels of IL-6, HSP-72, HSP-27, NF-кB, p38 MAPK, STAT-1, and STAT-3 and for mRNA expression of IL-6, HSP-72, and HSP-27. Repeated measures MANOVA for isokinetic peak torque revealed a significant decrease in strength at 24 and 48 hr post-exercise. Repeated measures MANOVA on muscle soreness and CK located a significant (p ≤ 0.05) main effect for time for both variables, but not for contraction type. Repeated measures MANOVA for cytokine serum variables demonstrated no significant results. Repeated measures MANOVA for muscle variables demonstrated no significant main effect for contraction, though a significant main effect for time was located. Pairwise comparisons demonstrated a significant difference from immediately post-exercise to 6 hr post-exercise for HSP-27. Gene expression of muscle variables demonstrated no significant results. Conclusion: The CON and ECC bouts demonstrated muscle damage through significant elevations in CK and muscle fatigue through significantly decreased torque production at 24 and 48 hr post-exercise. However, the damage induced during the acute bouts appears to have been insufficient to produce systemic and intramuscular signaling of the IL-6 pathway and its associated factors. Further human research still needs to be conducted on this pathway with the factors investigated here, though other exercise intensities and modes should be considered.Item The functional analysis of NPXY motif in β integrin in vivo.(2009-03-31T15:39:15Z) Ahn, Jeong H.; Lee, Myeongwoo.; Biology.; Baylor University. Dept. of Biology.NPXY (Asn-Pro-X-Tyr) is a conserved tyrosine phosphorylation motif that binds to PTB (phospho-tyrosine binding) domain of other protein. Integrins, a heterodimeric cell surface receptor for extracellular matrix (ECM), include two NPXY motifs in tandem on the cytoplasmic tails of β subunits. I generated a tyrosine to glutamate mutation mimicking constitutive phosphorylation of NPXY in βpat-3 integrin of Caenorhabditis elegans. The transgenic animals displayed disorganized muscle actin and abnormal gonad migration and tail morphology, suggesting that the phosphorylation of tyrosine causes defective phenotypes. In addition, the transgenic animals produced the high number of males, implying that the transgenic animals are similar to him-4/hemicentin alleles and that the lack of him-4 may cause the phosphorylation of NPXY. Genetic analyses revealed that tyrosine to phenylalanine mutations in both positions, βpat-3(YYFF), was able to suppress high incidence in male, mating ability, and egg-laying phenotypes of him-4 mutant, suggesting that a function of him-4 is to prevent the phosphorylation of βpat-3 NPXY. Taken together, our data suggest that changes in the ECM regulate the phosphorylation of the integrin NPXY.