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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Characterization of Neural Cells Derived from Reelin-deficient Schizophrenic Patient iPS Cells

Roberts, Nicole 01 January 2018 (has links)
Reelin is a large, extracellular glycoprotein that binds to several membrane receptors on neural stem cells (HNSCs), neural progenitor cells (NPCs), and neuroblasts of mammals to direct their migration. Previously, our lab established the presence of Reelin increased migration of wild-type fetal-derived HNSC's, both in vitro and in vivo. In addition, we demonstrated that Reelin protein treatment also increases the formation of radial glia via Notch-1 signaling, in vitro. Radial glia are precursors to NPCs, as well as a scaffold for neuroblast migration during cortical lamination. Reelin has long been associated with Schizophrenia (SZ). Because post-mortem brains are limited to describing the end-point of the disease, heterozygous haplodeficient Reelin knock-out (Reeler) mice are used to model developmental aspects of SZ in vivo. However, SZ is a complex, polyfactoral disease with a myriad of dysfunctional pathways that may have unforeseen effects on Reelin signaling. K. Brennand et al. (2014) reported low Reelin mRNA expression and cellular characteristics mirroring the Reeler mouse in induced pluripotent stem (iPS) cell-derived NPCs and neurons from living SZ patients. Building upon this and our work with stem cells, here we consider Reelin's effects on migration of Reelin-deficient iPS cell-derived NPCs. Reelin treatment of consists of secreted Reelin from transfected human embryonic kidney 293 cells (HEK 293) with the pCRL RELN gene-containing plasmid created by G. D'Arcangelo (1997) and given to us by T. Curran. Using the metric of cellular migration, this is the first time it have been shown that SZ iNPCs are capable of receiving and reacting to extracellular Reelin. Due to our validation of this model, further work using iPS cell-derived neural cells can confidently be used for future disease modeling and drug discovery of Reelin-deficient SZ.
62

Identification of Novel Antimalarials From Natural Product Inspired Libraries

Perry, David 01 January 2020 (has links)
To identify novel antimalarials from unexplored areas of chemical space, we have utilized two approaches: (a) using Torrey Pines Institute for Molecular Studies (TPIMS) proprietary high-density combinatorial libraries containing a large number of small molecule compounds residing largely in the underexplored areas of chemical space; and, (b) using novel, complexity-to-diversity/ring distortion of available natural products. The first approach involved the screening of more than 30 million compounds derived from 81 small molecule libraries, built on 81 distinct scaffolds. From this, we identified the pyrrolidine bis-cyclic guanidine library (TPI-1955) to be one of the most active and selective for antiplasmodial activity. In parallel, the synthesis of individual compounds derived from the deconvolution of the positional scanning library led to the identification of active selective antiplasmodial pyrrolidine bis cyclic guanidines. In the complexity to diversity/ring distortion approach, the indole alkaloid, yohimbine, has been re-engineered to alter the it's biological activity through a ring rearrangement synthesis pathway to develop a new series of antiplasmodial agents. One such antiplasmodial agent, Y7j, demonstrated good potency against the chloroquine-resistant Dd2 strain of parasites without eliciting cytotoxicity against human HepG2 cells. Y7j demonstrated stage specific action against plasmodium parasites in the late ring/trophozoite stage, and demonstrates the potential for ring distortion to drive new discoveries and change existing paradigms in both chemical biology and drug discovery.
63

BMP-7 Inhibits p38 and JNK Pathways and Increases M2 Macrophage Differentiation to Reduce Atherosclerosis in Apolipoprotein E-/- Mice

Shoulders, Heidi 01 January 2016 (has links)
We have previously shown that treating atherosclerosis with bone morphogenetic protein-7 (BMP-7) affects the presence of macrophage subtypes in vitro, however it remains unknown whether BMP-7 treatment affects development and progression of atherosclerosis in vivo at an early and mid-stage of the disease. We therefore performed a Day 5 (D5) and Day 28 (D28) study to examine BMP-7's potential to affect monocyte differentiation. Atherosclerotic plaque formation was developed using our standard method and ApoE-/- mice were sacrificed at D5 and D28 post-surgery. Treatment animals received intravenous injections of BMP-7 at 200µg/kg of bodyweight. Hematoxylin and Eosin morphological stain shows that BMP-7 is capable of significantly reducing plaque accumulation at D28 post-surgery vs. PLCA group, p < 0.05. At D5, plaque formation was reduced but not significant. Immunohistochemistry staining was performed to determine BMP-7's effect on monocytes (CD14), inflammatory M1 (iNOS) and anti-inflammatory M2 (CD206, Arginase-1) macrophages. Immunohistochemistry results show BMP-7 administration reduced pro-inflammatory monocytes and M1 macrophages at D5 and D28 compared to PLCA animals; however, monocytes were not statistically lower at D28. The anti-inflammatory M2 macrophage population was significantly less in PLCA animals compared to SHAM animals at D5 and D28. There was no significant difference in M2 macrophages between PLCA and PLCA + BMP7 animals at D5, however, by D28, PLCA + BMP7 animals showed a significant increase in M2 macrophages compared to PLCA animals. Western blot analysis confirms a significant increase in pro-survival kinase ERK and a significant reduction in pro-inflammatory kinases p38 and JNK in BMP-7 treated mice (D5 and D28, p < 0.05). ELISA showed a significant reduction in pro-inflammatory cytokines IL-6, MCP-1, and TNF-? (D5 and D28, p < 0.05) and a significant increase in anti-inflammatory cytokine IL-10 in BMP-7 treated mice (D5 and D28, p < 0.05). In summary, our data indicate BMP-7 treatment induces monocyte to M2 macrophage differentiation, increases anti-inflammatory cytokine levels (IL-1ra and IL-10), and improves blow flow velocity (D5 and D28, p < 0.05) compared to untreated animals. The mechanisms of monocyte to M2 macrophage differentiation appear to be mediated by the p38, JNK, and ERK pathways. This study suggests BMP-7 is capable of reducing inflammation and slowing progression of atherosclerosis at both an early and mid-stage of the disease.
64

The Role of Type-I Interferon in Limiting Spread and Killing of an Oncolytic RNA Virus in Prostate Cells

Kedarinath, Kritika 01 January 2016 (has links)
Prostate cancer is the second most prevalent cancer amongst men and there is an urgent need to address viable therapeutic options for its treatment. Development of viruses which target and kill cancer cells has gained momentum due to the first FDA approved oncolytic virus for treating human cancer patients. Our previous work with the RNA virus, Parainfluenza Virus 5 (PIV5), has led to the generation of mutants that are potential candidates for oncolytic viruses: 1) the hyperfusogenic (P/V/F) mutant has a mutated P/V and fusion gene which activates anti-viral responses and causes massive cell-cell fusion respectively, and 2) the Leader mutant has a mutated viral genomic promoter which kills cells due to overactive viral gene expression. The P/V/F mutant has shown effectiveness in reducing prostate tumor burden in a mouse model system, however, the specificity of these viruses is unclear, i.e. targeting cancerous prostate cells while leaving uninvolved cells unaffected. In this study, we addressed how these PIV5 mutants replicate in and killed tumor versus benign human prostate cells. Flow cytometry demonstrated that the mutants are able to infect and replicate in prostate tumor cells (22Rv1), resulting in effective cell killing. However, these mutants showed highly restricted spread in benign prostatic hyperplasia cells (BPH-1). Upon further exploration, it was determined that the restriction observed in the BPH-1 cells is due to the induction and signaling of type-I Interferon (IFN). This was confirmed upon treatment with an IFN-? neutralizing antibody, which relieved restricted spread of mutants in benign cells. BPH-1 cells infected with the mutants also showed upregulation of key anti-viral, IFN-induced genes such as TLR3, IFIT1, and OAS2. Upon characterization of the mutant viruses in an additional metastatic prostate cancer cell line (C4-2B), a restriction in viral spread was observed. The restricted spread did not correlate with production of high levels of type-I IFN, suggesting that other cytokines or intracellular factors can limit replication in tumor cells. Therefore, these studies lay the groundwork for further improving the specificity of oncolytic PIV5 mutants by exploiting type-I IFN pathways as well as other anti-viral factors.
65

The development of motuporamine derivatives and an investigation into their biological properties

Skruber, Kristen 01 January 2016 (has links)
This project investigates the synthesis of a class of compounds derived from a marine-based natural product and probes how iterative changes to its structure affect its derivatives' biological efficacy. The compound class of interest are the motuporamines which were isolated from the sea sponge Xestospongia exigua collected off the coast of Motupore island in Papua, New Guinea. The compounds for this project are predicated upon dihydromotuporamine C (Motu33), the compound that has been shown to be both cytotoxic to MDA-MB231 breast carcinoma cells and has antimetastatic efficacy. The motuporamine scaffold contains a large fifteen-membered saturated macrocycle and an appended polyamine component. A series of Motu33 derivatives were synthesized and evaluated for their ability to target the polyamine transport system as well as inhibit cell migration of human pancreatic cancer cells in vitro. By altering the polyamine component of the system we attempted to build smart antimetastatic compounds which target the upregulated polyamine transport system of human pancreatic cancers and block their migration.
66

Knowledge and Attitudes Regarding the Recent Zika Outbreak Among a Sample of South Florida Residents

Elakkari, Mohamed 01 January 2018 (has links)
South Florida has had the largest number of U.S. Zika infection cases during the recent outbreak. This study aimed at assessing South Floridians' basic knowledge, perceptions of the seriousness and susceptibility to Zika infection, their information sources and needs, as well as their attitudes towards the protective measures proposed by the CDC. We also wanted to assess whether any of those factors have affected the frequency of participants' undertaking of the protective behaviors. To this end, we designed an online questionnaire and surveyed the responses of five hundred South Floridians (Age=18-78 years). We found significant gaps in participants' knowledge about the risk groups, routes of transmission, treatment, and complications of Zika infection. Older age and college education were associated with significantly higher knowledge scores, while the presence of pregnant women in the household was associated with lower scores. About half of the participants perceived Zika to be a profoundly severe health problem, but less than one-third believed that their susceptibility to the infection is high. Most participants agreed that undertaking the measures that limit exposure to mosquito bites would be effective in preventing infections and that they would be able to carry-out these measures if recommended by the CDC, but a significantly lower proportion had similar responses to the items regarding protection against sexual transmission. There was a significant association between the frequency of protective behavior undertaking and respondents' beliefs about the seriousness and personal susceptibility to the infection, as well as their beliefs regarding the efficacy of the protective behaviors. Finally, most participants reported media platforms as their sources of information about Zika, while a minority of them received their information directly from healthcare professionals. These findings suggest that more targeted risk communication efforts are needed to increase South Floridians' awareness about Zika's public health threat.
67

Determining Differential Effects of Interleukin-2 on Innate and Adaptive Immune Cells in Lymphoid Organs and the Gastrointestinal Tract

Singh, Ayushi 01 January 2019 (has links)
Interleukin-2 (IL-2) is a pleiotropic cytokine demonstrated to be effective in treating cancer. However, the clinical use of IL-2 can be associated with severe side effects including gastrointestinal toxicity (GT). Similar GT symptoms are observed in inflammatory diseases such as CD (CD). Interestingly mounting evidence indicates a role for IL-2 in CD, but the underlying mechanisms are unknown. Indeed, studies on the in-vivo activities of IL-2 have mostly focused on secondary lymphoid organs and immune cells associated with them. Very few studies have addressed how IL-2 signals impact populations of immune cells in the gut. Here, we aim to identify and compare the effects of systemic IL-2 administration on six major leukocyte population and their subsets in mice using multicolor flow cytometry. While we confirmed previously observed changes in specific immune cell populations in the spleen, very few changes were seen in the gut and gut associated lymphoid tissues. Unexpectedly, a sharp decline was seen in B cells, most notably in Peyer's Patches, in mice treated with IL-2. Our data furthermore indicates that B cells in IL-2 treated mice undergo enhanced apoptosis in Peyer's Patches. Some studies suggest that changes in B cells may contribute to development of CD. Thus, this study may aid in defining ways in which IL-2 can contribute to disease etiology, and lead to novel treatments for CD.
68

Embryonic Stem Cell-Derived Exosomes Inhibit Doxorubicin-Induced Pyroptosis in Cell Culture Models

Tavakoli Dargani, Zahra 01 January 2018 (has links)
Doxorubicin (Dox) is a potent chemotherapeutic drug used for the treatment of various cancers. Unfortunately, its use is limited as Dox induces adverse cardiotoxicity (DIC) and muscle toxicity (DIMT), which are mediated through oxidative stress, ER stress, and inflammation. However, it remains unknown whether Dox induces an inflammation mediated cell death, called “pyroptosis”. The current study is designed to determine whether Dox induces pyroptosis in cardiac and muscle cell culture models. Moreover, the protective effects of embryonic stem cell-derived exosomes (ES-Exos) in inhibiting pyroptosis will also be determined. For this purpose, we designed two different cell culture models using H9c2 cadiomyoblasts and Sol 8 cells. For the DIC model, H9c2 were exposed to Dox to induce pyroptosis and then treated with exosomes. Cells were divided into 4 groups: Control, Dox, Dox+ES-Exos, and Dox+MEF-Exos (negative control). Furthermore, to generate the DIMT model, Sol 8 cells were incubated with Dox+THP-1 conditioned medium (TCM) to induce toxicity and inflammation, which was followed by exosomes treatment. We assigned cells into 5 groups: Control, Dox+TCM, Dox+TCM+ES-Exos, Dox+TCM+MEF-Exos (negative control), and Dox+TCM+ESExos+GW4869 compound (exosomes inhibitor, negative control). Our data shows that Dox treatment significantly increased pyroptotic marker expression including TLR-4, NLRP3, caspase-1, IL1-β, Caspase-11, and gasdermin-D as well as increased proinflammatory TNF-α and IL-6 expression in H9c2 cells. There was also a significant increase in caspase-1, IL1-β, and IL-18 expression in Dox+TCM treated Sol 8 cells. Conversely, increased pyroptosis and inflammation post-Dox treatment were inhibited by ES-Exos in both culture models. No significant changes observed upon MEF-Exos and GW4869 compound treatments. In conclusion, our data shows Dox induces pyroptosis and inflammation within cardiac and skeletal muscle cells, which can be inhibited following treatment with ES-exosomes. This is a novel study with new mechanistic observations on the pathophysiological role of pyroptosis in Dox-induced cardio and muscle toxicities.
69

Role of Lipid Peroxide Derived Dicarboxylic Acids in Atherosclerotic Calcification

Riad, Aladdin 01 January 2018 (has links)
Cardiovascular diseases, including atherosclerosis, are the leading cause of death in the United States. Atherosclerotic lesions are formed by deposition of lipids in the intima of arteries. Upon exposure to oxidative stresses, low-density lipoprotein (LDL) is converted to highly atherogenic oxidized LDL (ox-LDL) particles, contributing to disease development and progression. Advanced disease stages may result in calcification of lesions. This calcification process is important, as it has been shown to be associated with stable plaques that are less prone to rupture. Calcification is present in lipid rich domains of lesions, however neither the composition of the mineralized calcium deposits nor its relationship to lipid peroxidation or the lipid rich atherosclerotic core has previously been identified. This study provides evidence that the lipid peroxide derived dicarboxylic acid (DCA), azelaic acid (AzA) induces calcification in smooth muscle cells, thereby providing the link between calcification and overall plaque burden, and association of calcification with the lipophilic region of the lesion. The potential of lipid peroxide-derived lipophilic DCAs to promote calcification upon exposure to vascular smooth muscle cells was tested. 13-hydroperoxylinoleic acid (HPODE) treatment resulted in the cellular conversion to 9-oxononanoic acid (ONA) and AzA as determined by mass spectrometry analysis. Delivery of AzA via lysophosphatidylcholine (Lyso-PtdCho) micelles induced calcification of human aortic smooth muscle cells (HASMC). AzA was identified in calcified human and mouse atherosclerotic plaques. Calcification of HASMC due to AzA treatment resulted in a less inflammatory and oxidative environment as indicated by genetic expression. These results demonstrate that DCAs may contribute to atherosclerotic calcification thus accounting for the latter's relationship to plaque burden and association with lipids. This study also challenges the dogma that arterial calcification represents the deposition of calcium phosphate and has implications with the development of new therapeutic strategies in treating late stage atherosclerosis.
70

Biochemical Characterization of Rv2633c from Mycobacterium tuberculosis and the Effects of Mutagenesis on Iron Binding

Strickland, Kyle 01 January 2019 (has links)
Mycobacterium tuberculosis (Mtb) is a pathogenic bacterium that is the causative agent of the disease Tuberculosis (TB). TB kills an estimated 1.8 million people annually and roughly one third of the world's population carries Mtb in a dormant state. Drug resistant Mtb strains are on the rise, thus a new method of combating this disease is paramount. Mtb survival inside of macrophages requires overcoming various stressors such as; iron restriction, reactive oxygen species, and hypoxic conditions. Mtb employs the use of catalases, nitric oxide reductase, superoxide dismutase, and siderophores to aid in survival. These functions have also been found in a novel group of non-heme diiron binding proteins called hemerythrin-like proteins. The gene Rv2633c encodes a protein with the hemerythrin-like domain and has been shown to be upregulated under acidic or nutrient deficient conditions which coincides with Mtb infection of a macrophage. It has also been shown to be regulated by PhoP, Whib3, and DosR. In this work we expressed the wild type protein and several mutants heterologously in E. coli. The purified proteins were studied via UV-visible spectroscopic analysis, native polyacrylamide gel electrophoresis (native-PAGE) and analyzed for iron content. Our refined expression and purification protocol led to a significant increase in soluble protein with a di-iron cofactor. We found that mutagenesis of 11th amino acid, a histidine, led to the absence of the diiron co-factor. Reduction and autoxidation of protein was also achieved and characterized through UV-visible absorption. Native-PAGE gel analysis indicated only the dimeric form contained iron. This research is the first to produce large quantities of soluble iron laden protein, demonstrate that Rv2663c is capable of both reduction and autoxidation, and show it does not bind oxygen in a functional capacity. This information will enable future studies in protein crystallization, ligand interaction and in vivo studies.

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