Medicine and Health Sciences Commons^™

Genotoxin-Induced Acetylation Of The Werner Syndrome Protein (Wrn) And Effect On Its Dna Metabolic Function, Enerlyn Meliza Lozada Santiago

University of Kentucky Doctoral Dissertations

Loss of function of the WRN protein causes the genetic disorder Werner Syndrome that is characterized by increased cancer and premature aging. WRN belongs to the RecQ helicase family that plays key roles in preventing genome instability. In response to treatment with genotoxins, WRN is subject to post-translational modification. The relationship of post-translational modification of WRN with its function in DNA metabolism is unknown. There is accumulating evidence suggesting that WRN contributes to the maintenance of genomic integrity through its involvement in DNA replication. Consistent with this notion, WS cells are sensitive to DNA replication inhibitors and DNA damaging agents …

Identification Of Activities Involved In Cag/Ctg Repeat Instability, Nelson Lap Shun Chan

University of Kentucky Doctoral Dissertations

CAG/CTG repeat instability is associated with at least 14 neurological disorders, including Huntington’s disease and Myotonic dystrophy type 1. In vitro and in vivo studies have showed that CAG/CTG repeats form a stable hairpin that is believed to be the intermediate for repeat expansion and contraction.

Addition of extra DNA is essential for repeat expansion, so DNA synthesis is one of the keys for repeat expansion. In vivo studies reveal that 3’ CTG slippage with subsequent hairpin formation (henceforth called the 3’ CTG slippage hairpin) occurs during DNA synthesis. It is proposed that hairpin tolerance machinery is activated because prolonged …

Post-Transcriptional Regulation Of Afp And Igm Genes, Lilia M. Turcios

University of Kentucky Doctoral Dissertations

Gene expression can be regulated at multiple steps once transcription is initiated. I have studied two different gene models, the α-Fetoprotein (AFP) and the immunoglobulin heavy chain (IgM) genes, to better understand post-transcriptional gene regulation mechanisms. The AFP gene is highly expressed during fetal liver development and dramatically repressed after birth. There is a mouse strain-specific difference between adult levels of AFP, with BALB/cJ mice expressing 10 to 20-fold higher levels compared to other mouse strains. BALB/cJ mice express low levels of Zhx2 and thus incompletely repress AFP. Despite differences in steady state AFP mRNA levels in the adult liver …

The Absence Of Abcd2 Reveals A Novel Role For Peroxisomes In The Protection From Metabolic Syndrome, Jingjing Liu

University of Kentucky Doctoral Dissertations

ABCD2 (D2) is a peroxisomal ATP binding cassette (ABC) transporter that is expressed in brain, adrenal and liver. D2 is transcriptionally regulated by key transcriptional factors that control lipid and glucose metabolism. Therefore, we examined its role in adipose tissue. These studies revealed that D2 is highly abundant in adipose tissue and upregulated during adipogenesis. However, D2 deficiency does not affect either adipogenesis or lipid accumulation. An examination of the lipid profile of adipose tissue revealed the accumulation of C20 and C22 fatty acids in D2 deficient (D2‐/‐) mice. When challenged with a diet enriched in erucic acid (C22:1, 10% …

The Role Of The Nr4a Orphan Nuclear Receptor Nor1 In Vascular Cells And Atherosclerosis, Yue Zhao

University of Kentucky Doctoral Dissertations

The neuron-derived orphan receptor 1 (NOR1) belongs to the NR4A nuclear receptor subfamily. As an immediate early response gene, NOR1 is rapidly induced by a broad spectrum of physiological and pathological signals. Functional studies demonstrate NOR1 as a constitutively active ligand-independent nuclear receptor whose transcriptional activity is dependent on both expression level and posttranslational modifications. To date, an increasing number of studies have demonstrated a pivotal role of NOR1 in the transcriptional control of metabolism and the development of cardiovascular diseases.

In this dissertation, we demonstrate NOR1 expression in endothelial cells and sub-endothelial cells of human atherosclerotic lesions. In response …

The Effect Of Joint Mobilization On Functional Outcomes Associated With Chronic Ankle Instability, Matthew C. Hoch

University of Kentucky Doctoral Dissertations

Ankle sprains are among the most common injuries sustained by physically active individuals. Although ankle sprains are often considered innocuous in nature, a large percentage of individuals experience repetitive sprains, residual symptoms, and recurrent ankle instability following a single acute sprain; otherwise known as chronic ankle instability (CAI). In addition to repetitive ankle trauma, those with CAI experience reductions in functional capacity over the life span. This indicates that current intervention strategies for CAI are inadequate and require further investigation.

The objective of this dissertation was to explore differences in walking and running gait parameters between individuals with and without …

Role Of Pi3k-Akt Pathway In The Age Associated Decline In Tlr Mediated Activation Of Innate And Adaptive Immune Responses, Mosoka Papa Fallah

University of Kentucky Doctoral Dissertations

Immunosenescence results in reduced immune response to infections with Streptococcus pneumoniae as well as to pneumococcal polysaccharide vaccines. The antibody response to the capsular polysaccharide (CPS) provides protection against S. pneumoniae infection. CPS immunoresponse is T cell independent and needs the macrophage-derived cytokines such as IL-12, IL-6 and IL-1β to elicit an antibody response. We showed a cytokine dysregulation, i.e. a decrease in IL-12, IL-6 and TNF-α but an increase in IL-10, in the aged (18-24 months old comparable to >65 years in human) compared to young adult mouse (8-12 weeks less than 65 years old) splenic macrophages (SM) or …

Biochemical Characterization Of Human Mismatch Recognition Proteins Mutsα And Mutsβ, Lei Tian

University of Kentucky Doctoral Dissertations

The integrity of an organism's genome depends on the fidelity of DNA replication and the efficiency of DNA repair. The DNA mismatch repair (MMR) system, which is highly conserved from prokaryotes to eukaryotes, plays an important role in maintaining genome stability by correcting base-base mismatches and insertion/deletion (ID) mispairs generated during DNA replication and other DNA transactions. Mismatch recognition is a critical step in MMR. Two mismatch recognition proteins, MutSα (MSH2-MSH6 heterodimer) and MutSβ (MSH2-MSH3 heterodimer), have been identified in eukaryotic cells. MutSα and MutSβ have partially overlapping functions, with MutSα recognizing primarily base-base mismatches and 1-2 nt ID mispairs …

Dissecting The Biosyntheses Of Gilvocarcins And Ravidomycins, Madan Kumar Kharel

University of Kentucky Doctoral Dissertations

Gilvocarcin V (GV) and ravidomycin (RMV) exhibit excellent antitumor activities in the presence of near-UV light at low concentration maintaining a low in vivo cytotoxicity. Although, the exact molecular mechanism for in vivo actions of these antibiotics has yet to be determined, a [2+2] cycloaddition reaction of the vinyl side chain with DNA thymidine residues in addition to the inhibition of topoisomerase II and DNAhistone H3 cross-linking are reported for the GV’s mechanism of action. Such activities have made these molecules interesting candidates for the biosynthetic investigation to generate analogues with improved activity/solubility. Previous biosynthetic studies have suggested that the …

Explorations In Homeoviscous Adaptation And Mass Spectral Analysis Of Membrane Lipids, Michael Douglas Timmons

University of Kentucky Doctoral Dissertations

The focus of this dissertation is centered on the mass spectral analysis of lipids and changes occurring in keeping with the concept of homeoviscous adaptation [1]. Homeoviscous adaptation is the process of modification of membrane lipids in response to environmental stimuli [1]. Dissertation investigations applied this concept to prokaryotic and eukaryotic organisms, and expanded the perception of environmental factors from exogenous organic solvents to intracellular environment.

The field of lipidomics deals with the analysis of phospholipid and fatty acid components of membranes the changes that occur due to environmental stimuli and their biological significance [2-6]. The high sensitivity of mass …

Substrate And Regulation Of Mitochondrial Μ-Calpain, Aashish Joshi

University of Kentucky Doctoral Dissertations

μ -Calpain is localized to the mitochondrial intermembrane space. Apoptosisinducing factor (AIF), which executes caspase-independent cell death, is also localized to the mitochondrial intermembrane space. Following processing at the N-terminus, AIF becomes truncated (tAIF) and is released from mitochondria. The protease responsible for AIF processing has not been established. The same submitochondrial localization of mitochondrial μ-calpain and AIF gives support to the hypothesis that mitochondrial μ-calpain may be responsible for processing AIF. Atractyloside-induced tAIF release in rat liver mitochondria was inhibited by cysteine protease inhibitor MDL28170, but not by calpain inhibitors PD150606 or calpastatin. Moreover, μ-calpain immunoreactivity was difficult to …

The Interplay Between The Expression And Functions Of Wnt13 Isoforms During Apoptosis In Bovine Aortic Endothelial Cells, Tao Tang

University of Kentucky Doctoral Dissertations

Wnt proteins are crucial for development/homeostasis by controlling cell fate including apoptosis (Moon RT et al. 1997). Three humanWnt13 isoforms were identified: the secreted Wnt13A, mitochondrial Wnt13B, and nuclear Wnt13C forms; and nuclear Wnt13 had an increased sensitivity to LPS/TNF-induced apoptosis in primary endothelial cells (EC); both Wnt13B and C mRNA contain two start codons (AUG+1 and +74), but the same protein encoded from AUG+74 by Wnt13C was expressed lower than Wnt13B (Struewing IT et al.2006). We hypothesize that during EC apoptosis, the nuclear Wnt13C expression is regulated translationally; nuclear Wnt13 favors apoptosis through regulating the activity/expression of apoptosis-related factors; …

Insights Into Expression, Cellular Localization, And Regulation Of Supernatant Protein Factor, A Putative Regulator Of Cholesterol Biosynthesis, Elzbieta Ilona Stolarczyk

University of Kentucky Doctoral Dissertations

SPF (Supernatant Protein Factor) is a cytosolic protein that stimulates at least two enzymes in the cholesterol biosynthetic pathway: squalene monooxygenase and HMGCoA reductase. The mechanism of action has not been established but may be related to lipid transfer between intracellular membranes.

There are three human genes for SPF: SEC14L2 (SPF1), SEC14L3 (SPF2) and SEC14L4 (SPF3). The present study differentiates these closely related genes by evaluating their tissue-specific and relative expression levels. SPF1 mRNA was found to be most abundant in liver, mammary gland and stomach. SPF2 showed negligible expression in all tissues tested; SPF3 expression pattern was similar to …