Cellular and Molecular Physiology Commons^™

From Young To Old: The Effects Of Sedentary-Aging And Exercise Interventions On Structural Plasticity Of Lumbar Motor Neurons, Nmj, And Glial Cell Line-Derived Neurotrophic Factor Expression, Alberto Felipe Cintron-Colon

Dissertations

Neuromuscular weakness has been associated with age progression. A possible reason is a disconnection between muscle and neuron, causing components from both the central and peripheral nervous systems to deteriorate. Exercise, however, has beneficial effects for both muscle and nervous tissue, inducing neuroprotection. Neurotrophic factors are powerful regulators of neuronal maintenance and synaptic strength. Glial cell line-derived neurotrophic factor (GDNF) is a neurotrophic factor that has been shown to be a potent survival factor for somatic motor neurons that innervate skeletal muscle.

This study aims to evaluate changes in structural plasticity of motor neurons in the lumbar spinal cord and …

The Role Of Glycogen Synthase Kinase 3 Β (Gsk-3Β) At The Cardiac Myofilament, Marisa Jean Stachowski

Dissertations

Altered kinase activity and localization is gaining appreciation as a mechanism contributing to cardiovascular disease. Previous work suggests that the kinase glycogen synthase kinase 3 β (GSK-3β) regulates contractile function of the myofilament, but this work was performed in vitro. The goal of this work was to investigate GSK-3β’s in vivo role in regulating myofilament function, the mechanisms involved, and the translational relevance in disease. GSK-3β’s myofilament localization was confirmed in wild type mouse and human tissue via western blot of myofilament enriched tissue and immunofluorescence. These experiments also revealed that GSK-3β phosphorylated at Y216 binds to the z-disc. We …

Critical Role Of C-Jun N-Terminal Kinase Signaling In Binge Alcohol-Driven Atrial Arrhythmic Remodeling, Jiajie Yan Yan

Dissertations

Holiday Heart Syndrome (HHS) is cardiac arrhythmia induced by binge alcohol consumption, a drinking pattern affects 38 million adults in our society. Atrial fibrillation (AF) is the most frequently diagnosed arrhythmia in HHS and causes significant morbidity and mortality. Despite the intensive prevention effort nationwide, the binge drinking population keeps rising. However, no effective treatment strategies are available for binge drinking induced AF due to the unknown underlying mechanisms. In this thesis, I aim to elucidate the mechanisms of binge alcohol-promoted atrial arrhythmogenicity by using a mouse model of repeated binge alcohol exposure established in the Ai Lab.

The Ai …

Serine 910 Phosphorylation Of Focal Adhesion Kinase Is Critical For Costamere Assembly, Miensheng Chu

Dissertations

Tyrosine-phosphorylated FAK is required for the hypertrophic response of cardiomyocytes to growth factors and mechanical load, but the role of FAK serine phosphorylation in this process is unknown. Endothelin-1 (ET-1; 1-100nM, 2-30min) and other hypertrophic factors induced a time- and dose-dependent increase in FAK-S910 phosphorylation in neonatal rat ventricular myocytes (NRVM). FAK-S910 phosphorylation required ET_AR-dependent activation of PKCδ and Src via parallel Raf-1→MEK1/2→ERK1/2 and MEK5→ERK5 signaling pathways. Using co-immunoprecipitation, TIRF-microscopy and FRAP, ET-1 stimulation of NRVM expressing a nonphosphorylatable, S910A-FAK mutant decreased the interaction of paxillin and vinculin within costameres. This interaction was important in stabilizing α-actinin within …

Molecular Analysis Of The Effects Of Atrazine On Xenopus Laevis Frogs, Ronald Edward Celestine

Dissertations

Atrazine, the most commonly used herbicide in the U.S., has been implicated as one of the factors that may be causing the worldwide decline of amphibians. First, I examined effects of atrazine on laboratory raised Xenopus laevis tadpoles, treated from 5 days post fertilization to NF stage 65/66 with a concentrationof 25 ppb of atrazine. This study showed no significant difference in body weight, length and metamorphic rate.

Second, I used DNA microarrays to examine mRNA expression levels of genes in atrazine treated and control Xenopus laevis tadpoles. I found significant changes in gene expression levels of 18 genes. These …