Life Sciences Commons^™

The Distribution And Functional Properties Of Pmld-Linked Cx47 Mutations On Cx47/Cx47 Homotypic And Cx47/Cx43 Heterotypic Gap Junctions, Mi Seong Kim

Electronic Thesis and Dissertation Repository

Gap junctions (GJ) allow direct intercellular communication, and consist of connexins (Cx). In the mammalian central nervous system, oligodendrocytes express Cx29, Cx32 and Cx47, whereas astrocytes express Cx26, Cx30 and Cx43. Cx47/Cx47 GJs couple oligodendrocytes, and Cx47/Cx43 channels are the primary heterotypic GJs at oligodendrocyte/astrocyte junctions. Interestingly, mutations in Cx47 have been linked to central hypomyelinating Pelizaeus Merzbacher-like Disease (PMLD). My aim is to determine the cellular distribution and functional properties of PMLD-associated Cx47 mutants (I46M, G149S, G236R, G236S, M286T, T398I). All mutants were detected at the cell-cell interface. These mutants, except G149S and T398I, showed no electrical coupling in …

Post-Transcriptional Regulation Of Telomerase Reverse Transcriptase (Tert) In Human Embryonic Stem Cells Cultured Under Varying Oxygen Microenvironments, Lida Radan

Electronic Thesis and Dissertation Repository

Recent evidence points to extra-telomeric roles of telomerase in regulating stem cell function. In this study, human embryonic stem cells (hESCs) were cultured in 20% or 2% oxygen for up to 5 days and evaluated for telomerase reverse transcriptase (TERT) expression and telomerase activity. Results showed increased cell survival and maintenance of the undifferentiated state with elevated levels of nuclear TERT in 2% oxygen cultured hESCs despite no significant difference in telomerase activity. Pharmacological inhibition of TERT caused spontaneous differentiation while inhibition of the telomerase RNA component (TERC) did not. RT-PCR analysis revealed variations in transcript levels of full-length and …

Human Cerebrovascular Endothelial Cell Responses In Severe Sepsis, Christopher J. Blom

Electronic Thesis and Dissertation Repository

Sepsis-associated encephalopathy (SAE) is an independent predictor of mortality in severe sepsis patients. Mechanisms of SAE are poorly characterized. Pro-inflammatory mediators are up-regulated in blood plasma of severe sepsis patients and may lead to activation/dysfunction of cerebrovascular endothelial cells (CMEC) of the blood-brain barrier (BBB) – potentially contributing to brain dysfunction. The objective of the present study was to determine the effects/mechanisms of both human severe sepsis blood plasma (hSSP; 20% v/v) and a mixture of 8 cytokines/chemokines that mimicked physiological concentrations of cytokines/chemokines in hSSP (cytomix; SSCM) on human-derived CMEC (hCMEC/D3) activation/dysfunction

in vitro. hSSP-stimulation up-regulated hCMEC/D3 pro-adhesive …

Kiss1r Induces Human Mammary Epithelial Cell Invasiveness And Promotes Breast Cancer Cell Migration And Invasion Via Iqgap1, Donna Cvetkovic

Electronic Thesis and Dissertation Repository

Kisspeptins (KP), peptide products of the kisspeptin-1 (KISS1) gene are the endogenous ligands for a G protein-coupled receptor (KISS1R). KISS1 acts as a metastasis suppressor in numerous human cancers. However, recent studies have demonstrated that an increase in KISS1 and KISS1R expression in human breast tumors correlates with higher tumor grade and metastatic potential. We have previously shown that KP-10, the most potent KP, stimulates invasion of estrogen receptor (ER)-negative breast cancer cells via transactivation of the epidermal growth factor receptor (EGFR). Here, I report that KP-10 treatment of the ER-negative non-malignant mammary epithelial MCF10A cells, or stable …

The Role Of Transforming Growth Factor Alpha In Osteoarthritis And Skeletal Development, Shirine E. Usmani

Electronic Thesis and Dissertation Repository

Osteoarthritis (OA) is the most common joint disease and a major cause of physical disability, however no disease modifying treatments are available. To better understand the molecular mechanisms involved, my colleagues previously performed microarray studies on a surgical rodent model of OA. Transforming growth factor alpha (TGFa) was identified as a novel growth factor involved in cartilage degeneration and subsequent experiments revealed that it induced an OA-like phenotype in articular chondrocytes. These findings lead to the overarching hypothesis for my thesis: TGFa promotes OA.

I began by studying TGFa’s interaction with endothelin receptor A (ET(A)R) as this signaling system is …

Uncovering Dual Roles For Perk Signaling During Experimentally Induced Pancreatitis, Elena Fazio

Electronic Thesis and Dissertation Repository

Pancreatitis is characterized by inappropriate activation of digestive enzyme

precursors, or zymogens, local and systemic inflammation, dysregulation of

cellular calcium (Ca2+), and induction of the unfolded protein response (UPR).

The UPR consists of three distinct pathways all of which are activated during

pancreatitis. However, the molecular roles of each remain unclear. The

protein kinase RNA (PKR)-like ER kinase (PERK) pathway reduces general

protein translation by phosphorylating eIF2!, and is activated within minutes

of initiating pancreatic damage. Microarray analysis carried out by our lab

revealed robust upregulation of the PERK pathways members Activating

Transcription Factor (ATF) 3 and stanniocalcin (STC) 2. …

Identification And Characterization Of The Arabidopsis Homolog Of The Yeast Trex-2 Complex, Gang Tian

Electronic Thesis and Dissertation Repository

Nuclear pore complexes (NPCs) are vital to nuclear-cytoplasmic communication in eukaryotes. The yeast Thp1-Sac3-Cdc31-Sus1 complex, also known as the TREX-2 complex, is anchored to the NPC via the nucleoporin Nup1, and is essential for mRNA export. In this study, the Arabidopsis homolog of the yeast TREX-2 complex was discovered. Physical and functional evidence support the identification of the Arabidopsis orthologs of the yeast Thp1 and Nup1. Of three Sac3 Arabidopsis homologs, two are putative TREX-2 components. Surprisingly, none are required for mRNA export as is the yeast Sac3. Physical association with TREX-2 was observed for the two Cdc31 homologs, but …

The Developmental And Adaptive Role Of Mitogen Activated Protein Kinase Pathways During Preimplantation Development, Christine E. Bell

Electronic Thesis and Dissertation Repository

The preimplantation period of development represents the highest interval of embryonic loss throughout pregnancy. It is therefore imperative that we elucidate the mechanisms involved in regulating preimplantation embryonic responses to stress and that govern development. The MAPK pathways are involved in both responding to environmental stress and regulation of development throughout embryogenesis, and are therefore good candidates to study the mechanisms involved in preimplantation embryonic adaptation to stress and development. The preimplantation embryo culminates in the development of a fluid filled structure called the blastocyst. It is at this stage the first differentiation events occur and the trophectoderm (TE), which …