Molecular Biology Commons^™

The Regulation Of Pannexin1 And Pannexin2 In The Skin In Health And Disease, Rafael E. Sanchez Pupo

Electronic Thesis and Dissertation Repository

Pannexins (PANX1, 2, 3) are a family of channel-forming glycoproteins that mediate intracellular and paracrine signaling. In contrast to PANX2, PANX1 has been extensively investigated in the skin, modulating cell differentiation, wound healing, and melanoma development. PANX1 and PANX2 can co-exist in the same cell and form mixed channels where their glycosylation seems to regulate their intermixing. N-glycosylation and caspase cleavage have been proposed as modulators of the function of PANX1, but their effects on PANX2 are unknown. We explored the PANX2 expression in mouse skin and showed that a Panx2 splice variant (PANX2-202) is continuously expressed throughout aging skin. …

Discovery Of Novel Mechanisms Regulating Cancer Extravasation In The Chorioallantoic Membrane Model, Yohan Kim

Electronic Thesis and Dissertation Repository

Cancer metastasis is a multistep process that begins with the invasion of tumour cells into the stroma and migration towards the blood vessels. Tumour cells that have entered the bloodstream must then survive and leave by a process known as extravasation. Finally, extravasated cells proliferate and establish the secondary site in the metastatic cascade. Although extravasation encompasses key events during cancer cell invasion to aid in the development of effective treatments, an in vivo model that rapidly, reproducibly and economically recapitulates cancer cell extravasation is needed. Therefore, the objectives of my research were to 1) establish and validate an in …

Assessing The Structure-Function Relationships Of The Apolipoprotein(A) Kringle Iv Sub-Type 10 Domain, Matthew J. Borrelli

Electronic Thesis and Dissertation Repository

Elevated plasma lipoprotein(a) (Lp(a)) is the most prevalent heritable risk factor in the development of cardiovascular disease. The apolipoprotein(a) (apo(a)) component of Lp(a) is strongly implicated in the pathogenicity of Lp(a). It is hypothesized that the inflammatory potential of Lp(a)/apo(a) is mediated by the lysine binding ability of the apo(a) kringle IV10 (KIV10) domain, along with its covalently bound oxidized phospholipid (oxPL). Using targeted mutagenesis, two novel null alleles for the LPA gene that generate non-secretable apo(a) species have been identified, resulting from amino acid substitutions in the KIV10 domain. A potential mechanism by which KIV10 oxPL modification is enriched …

Microvascular Stenosis In Critical Limb Ischemia: Role Of Partial Endothelial To Mesenchymal Transition, Jacqueline M. Chevalier

Electronic Thesis and Dissertation Repository

Critical limb ischemia (CLI) is a widespread and debilitating manifestation of atherosclerosis. Unfortunately, revascularization strategies are often precluded or unsuccessful, resulting in amputation. A major reason for treatment failure is likely co-existing abnormalities in ­­the microvasculature. However, the specific microvascular defects present in end-stage PAD in humans remain unknown.

The purpose of this study was to delineate abnormalities in the microvascular wall in the critically ischemic skeletal muscle of patients with CLI.

To elucidate the microvascular landscape in CLI, we studied human tibialis anterior and gastrocnemius muscles harvested from below-knee amputations of 10 individuals with CLI. Control muscles are from …

Effects Of G Protein Signalling Modulator 3 On Cellular Signalling, Aneta A. Surmanski

Electronic Thesis and Dissertation Repository

G protein coupled receptors (GPCRs) promote G protein heterotrimer (Gα·GDP/Gbg) activation.GPCRsignalling is limited via G protein GTPase activity and b-arrestin-receptor interactions. G Protein Signalling Modulators (GPSMs) are proteins that may influence receptor signalling through G protein activity. GPSM3 modulates their activity by binding to Ga_i-GDP, limiting nucleotide exchange and preventing its re-association to Gbg. The impact of GPSM3 on signalling is unknown.We hypothesize that GPSM3 will decrease Ga_i-dependent signalling while promoting Gbg-dependent signalling in G_i-coupled GPCRs.

GPSM3 significantly inhibited b-arrestin recruitment to α_2A-adrenergic and m-opioid receptors via a Gbg-dependent mechanism, …

The Cdk-Resistant Prb-E2f1 Complex Recruits Chromatin-Organizing Proteins To Repetitive Dna Sequences, Charles A. Ishak

Electronic Thesis and Dissertation Repository

This thesis investigates mechanistic links between genome integrity and the recruitment of chromatin organizing proteins to repetitive DNA sequences mediated by the retinoblastoma tumor suppressor protein (pRB). I demonstrate that a CDK-resistant interaction between the pRB C-terminus and the E2F1 coiled-coil marked box domain establishes a scaffold that facilitates recruitment of multiple chromatin-organizing proteins to repetitive sequences across the genome throughout the cell cycle. Specifically, pRB recruits the enhancer-of-zeste-homologue 2 (EZH2) histone methyltransferase to establish repressive facultative heterochromatin at repetitive sequences, and the Condensin II complex to ensure proper DNA replication and mitotic progression. To disrupt the CDK-resistant pRB-E2F1 interaction …

Investigating E2f Independent Cell Cycle Control And Tumor Suppression By Prb, Michael J. Thwaites

Electronic Thesis and Dissertation Repository

Cellular division is primarily controlled at the G1 to S-phase transition of the cell cycle by the retinoblastoma tumor-suppressor protein (pRB). The ability of pRB to restrict S-phase entry is primarily attributed to the repression of E2F transcription factors required to upregulate cell cycle target genes necessary for cellular division. Interestingly, while pRB is disrupted in the vast majority of human cancers, mutations typically target upstream regulators of pRB leading to inactivation through hyperphosphorylation. The rarity of direct pRB mutations suggests that the regulation of the cell cycle by pRB may involve additional mechanisms outside of E2F repression, as this …

Characterizing The Human Vaginal Microbiome Using High-Throughput Sequencing, Jean Megan E. Macklaim

Electronic Thesis and Dissertation Repository

The human vaginal microbiome undoubtedly has a significant role in reproductive health and for protection from infectious organisms. Recent efforts to characterize the bacterial species of the vagina using molecular techniques have uncovered an unexpected diversity. Using high-throughput sequencing I sought to describe the structure and function of the vaginal microbiome under different physiological states including healthy, bacterial vaginosis (BV), post-menopausal vaginal atrophy, and acute vulvovaginal candidiasis (VVC).

Partial 16S rRNA gene sequencing revealed that healthy, asymptomatic women most often have vaginal biotas dominated by Lactobacillus iners or L. crispatus. In contrast, BV is a heterogeneous, highly diversified condition …

Exploring The Structure And Biochemistry Of Oxidation-Mediated Inhibitation Of The Peptidyl-Prolyl Isomerase Pin1, Brendan T. Innes

Electronic Thesis and Dissertation Repository

Pin1 is a phosphorylation-dependent peptidyl-prolyl isomerase that has been shown to be neuroprotective in aging-related neurodegenerative diseases such as Alzheimer's disease (AD). However, it is not active in AD brain, and a recent proteomic screen of Mild Cognitive Impairment (MCI) brain samples revealed that Pin1 is oxidized in the brains of these pre-AD patients. This suggests that this oxidation may be the cause of the loss of the neuroprotective Pin1 function in AD. The Pin1 active site contains a functionally critical cysteine residue (Cys113) with a low predicted pKa, making it highly susceptible to oxidation. We hypothesize that Pin1 is …

Human Adenovirus E1a Binds And Retasks Cellular Hbre1, Blocking Interferon Signalling And Activating Virus Early Gene Transcription, Gregory J. Fonseca

Electronic Thesis and Dissertation Repository

Upon infection, human adenovirus (HAdV) must block interferon signaling and activate the expression of its early genes to reprogram the cellular environment to support virus replication. During the initial phase of infection, these processes are orchestrated by the first HAdV gene expressed during infection, early region 1A (E1A). E1A binds and appropriates components of the cellular transcriptional machinery to modulate cellular gene transcription and activate viral early genes transcription. We have identified hBre1/RNF20 as a novel target of E1A. hBre1 is an E3 ubiquitin ligase which acts with the Ube2b E2 conjugase and accessory factors RNF40 and WAC1 to monoubiquitinate …

Regulation Of Lipid Homeostasis, Inflammatory Signalling And Atherosclerosis By The Peroxisome Proliferator-Activated Receptor Delta, Lazar A. Bojic

Electronic Thesis and Dissertation Repository

The peroxisome proliferator-activated receptor (PPAR) δ is a ligand-dependent transcription factor that has been implicated in metabolic and inflammatory regulation. The molecular and physiological mechanisms by which PPARδ activation regulates lipid metabolism, inflammatory signaling and protection from atherosclerosis in states of metabolic disturbance such as insulin resistance and dyslipidemia, were investigated in a series of in vitro and in vivo studies. In vitro experiments demonstrated that PPARδ activation inhibits atherogenic lipoprotein-induced lipid accumulation and the associated proinflammatory responses. The primary mechanisms for these effects were increased fatty acid β-oxidation, decreased lipoprotein lipase (LPL) activity, reduced MAPK signaling and improved insulin …

Involvement Of Interleukin-33/St2 In Myocardial Dysfunction In Murine Model Of Sepsis, Yoonmi Choe

Electronic Thesis and Dissertation Repository

The disruption of myocardial extracellular matrix (ECM) has been implicated in myocardial dysfunction during sepsis. However, the underlying mechanism(s) are not clear. Interleukin-33 (IL-33) is a cytokine which regulates collagen synthesis in various cardiac pathologies. The purpose of the present study is to test whether IL-33 contributes to sepsis-induced myocardial dysfunction through regulation of matrix metalloproteinase-9 (MMP-9). The in vivo, feces-induced peritonitis (FIP) in mice and in vitro lipopolysaccharide (LPS) treatments to isolated cardiomyocytes were used. In FIP mice, myocardial IL-33 and MMP-9 expression were increased and myocardial contractility was decreased. Myocardial function in FIP mice was improved when treated …

Characterization Of Cardiomyopathy In A Mouse Model Of Duchenne Muscular Dystrophy (Dmd) Using Echocardiography, Dce-Ct, And Pet-Fdg, Seyed Hamed Moazami

Electronic Thesis and Dissertation Repository

Duchenne muscular dystrophy (DMD) is an X-linked recessive neuromuscular disease that is the result of a loss of functional dystrophin, which causes cardiomyocyte fibrosis and death, leading to cardiomyopathy. In this thesis, I have utilized dynamic contrast-enhanced computed tomography (DCE-CT), positron emission tomography-fluorodeoxyglucose (PET-FDG), echocardiography, and traditional histology to longitudinally assess disease progression and degree of cardiomyopathy in a murine model of DMD (mdx:utrn-/-). No significant changes were observed in the blood flow, blood volume, or cardiac volume measured via DCE-CT, nor in standard uptake value (SUV) of glucose as measured by PET-FDG in the left myocardium between and within …