Matching Items (18)
ContributorsMozart, Wolfgang Amadeus, 1756-1791 (Composer)
ContributorsMozart, Wolfgang Amadeus, 1756-1791 (Composer)
Description
Treatment of cerebral aneurysms using non-invasive methods has existed for decades. Since the advent of modern endovascular techniques, advancements to embolic materials have largely focused on improving platinum coil technology. However, the recent development of Onyx®, a liquid-delivery precipitating polymer system, has opened the door for a new class of embolic materials--liquid-fill systems. These liquid-fill materials have the potential to provide better treatment outcomes than platinum coils. Initial clinical use of Onyx has proven promising, but not without substantial drawbacks, such as co-delivery of angiotoxic compounds and an extremely technical delivery procedure. This work focuses on formulation, characterization and testing of a novel liquid-to-solid gelling polymer system, based on poly(propylene glycol) diacrylate (PPODA) and pentaerythritol tetrakis(3-mercaptopropionate) (QT). The PPODA-QT system bypasses difficulties associated with Onyx embolization, yet still maintains non-invasive liquid delivery--exhibiting the properties of an ideal embolic material for cerebral aneurysm embolization. To allow for material visibility during clinical delivery, an embolic material must be radio-opaque. The PPODA-QT system was formulated with commercially available contrast agents and the gelling kinetics were studied, as a complete understanding of the gelling process is vital for clinical use. These PPODA-QT formulations underwent in vitro characterization of material properties including cytotoxicity, swelling, and degradation behaviors. Formulation and characterization tests led to an optimized PPODA-QT formulation that was used in subsequent in vivo testing. PPODA-QT formulated with the liquid contrast agent ConrayTM was used in the first in vivo studies. These studies employed a swine aneurysm model to assess initial biocompatibility and test different delivery strategies of PPODA-QT. Results showed good biocompatibility and a suitable delivery strategy, providing justification for further in vivo testing. PPODA-QT was then used in a small scale pilot study to gauge long-term effectiveness of the material in a clinically-relevant aneurysm model. Results from the pilot study showed that PPODA-QT has the capability to provide successful, long-term treatment of model aneurysms as well as facilitate aneurysm healing.
ContributorsRiley, Celeste (Author) / Vernon, Brent L (Thesis advisor) / Preul, Mark C (Committee member) / Frakes, David (Committee member) / Pauken, Christine (Committee member) / Massia, Stephen (Committee member) / Arizona State University (Publisher)
Created2011
Description
The innate immune system serves as an immediate response to pathogenic infection and an informant to the adaptive immune system. The 2′,5′-oligoadenylate (2-5A) synthetase (OAS)–RNase-L system is a component of the innate immune system induced by interferons (IFNs) and serves to eliminate viral infections. In humans, three enzymatically active OAS proteins exist, OAS1, OAS2, and OAS3. Recent evidence suggests variations in cellular localization of OAS proteins may influence the impact and influence of those proteins on viral replication. However, viral suppression mechanisms involving specific OAS proteins are still unclear for most viruses. Here, I overexpress different isoforms of OAS and determined that though viruses within the same family have similar replication strategies, the extent to which each OAS protein impacts viral replication for Flaviviruses, and Alphaviruses varies. In contrast to the innate immune system, the adaptive immune system provides specific and long-lived immune responses. In the context of cancer, T cells have been shown to play a prominent role in tumor regression. It has previously been demonstrated that administration α-CTLA-4/α-PD-L1 immune checkpoint blockade (ICB) to mice inoculated with a K7M2 metastatic osteosarcoma (mOS) cell line resulted in ~50% survival. Here, I sought to determine biological differences among murine responders and non-responders to ICB for mOS to understand better what factors could increase ICB efficacy. A prospective culprit is a variance in circulating antibodies (Abs). I have shown that sera from mice, before inoculation with mOS or ICB, display distinct differences in Ab repertoire between responders and non-responders, suggesting the presence or absence of particular Abs may influence the outcome of ICB. Recent studies have also shown that malleable environmental factors, such as differences in microbiome composition, can yield subsequent changes in circulating Abs.
Strong associations have been made between host-microbiome interactions and their effects on health. Here, I study potential associations of microbiome-mediated impacts on ICB efficacy for mOS. Additionally, I sought to determine potential changes in T-cellular response to mOS due to modulations in microbiome composition and showed that ICB efficacy can change in conjunction with microbiome composition changes in a murine model.
ContributorsDi Palma, Michelle Pina (Author) / Blattman, Joseph N (Thesis advisor) / Li, Yize (Thesis advisor) / Anderson, Karen S (Committee member) / McFadden, Grant (Committee member) / Arizona State University (Publisher)
Created2023
Description
Cell death is a powerful tool through which organisms can inhibit the spread of viruses by preventing their replication. In this work, I used viral and chemical stressors to elucidate the mechanisms by which one anti-viral system might be activated over another, focusing on the programmable death pathway necroptosis and Protein Kinase R (PKR). PKR can detect viral dsRNA and trigger antiviral effects such as cessation of translation and induction of programmed death. Necroptosis is a rapid cellular death that can be induced via sensors such as DNA-dependent activator of IFN-regulatory factors (DAI), also known as Z-DNA-binding protein 1 (ZBP1). DAI contains a Z-form nucleic acid (ZNA) binding domain. E3, the primary vaccinia virus (VACV) interferon resistance protein, contains a similar domain in its amino terminus. We have previously reported this domain to be necessary for the inhibition of both PKR activation and DAI/ZBP1-mediated necroptosis.
Monkeypox virus is a reemerging human pathogen. Despite a partial amino-terminal deletion in its E3 homolog, it does not activate PKR. In chapter 2, I show that MPXV produces less dsRNA than VACV, which could explain how the virus avoids activating PKR.
The amino-terminus of vaccinia is associated with ZNA binding, inhibition of PKR, and inhibition of necroptosis. To determine the roles of PKR inhibition and ZNA binding in necroptosis inhibition, I characterized the VACV mutants Za(ADAR1)-E3, which binds ZNA but does not inhibit PKR, and E3:Y48A, which cannot bind ZNA. I found that while Za(ADAR1)-E3 fails to induce necroptosis, E3:Y48A does not activate PKR but does induce necroptosis. This suggests that Z-form nucleic acid binding is not necessary for vaccinia E3-mediated inhibition of PKR, nor is the inhibition of PKR sufficient for the inhibition of necroptosis.
Finally, all known ZNA-binding proteins have immune functions and home to stress granules. I asked if stress granule formation alone could lead to necroptosis. I found that in L929 cells sodium arsenite, a known inducer of stress granules, could trigger DAI-dependent necroptosis. This suggests that DAI/ZBP1 is not necessarily a sensor of viral ligands but perhaps is a sensor of stress signals brought about by infection.
Monkeypox virus is a reemerging human pathogen. Despite a partial amino-terminal deletion in its E3 homolog, it does not activate PKR. In chapter 2, I show that MPXV produces less dsRNA than VACV, which could explain how the virus avoids activating PKR.
The amino-terminus of vaccinia is associated with ZNA binding, inhibition of PKR, and inhibition of necroptosis. To determine the roles of PKR inhibition and ZNA binding in necroptosis inhibition, I characterized the VACV mutants Za(ADAR1)-E3, which binds ZNA but does not inhibit PKR, and E3:Y48A, which cannot bind ZNA. I found that while Za(ADAR1)-E3 fails to induce necroptosis, E3:Y48A does not activate PKR but does induce necroptosis. This suggests that Z-form nucleic acid binding is not necessary for vaccinia E3-mediated inhibition of PKR, nor is the inhibition of PKR sufficient for the inhibition of necroptosis.
Finally, all known ZNA-binding proteins have immune functions and home to stress granules. I asked if stress granule formation alone could lead to necroptosis. I found that in L929 cells sodium arsenite, a known inducer of stress granules, could trigger DAI-dependent necroptosis. This suggests that DAI/ZBP1 is not necessarily a sensor of viral ligands but perhaps is a sensor of stress signals brought about by infection.
ContributorsJohnson, Brian Patrick (Author) / Jacobs, Bertram L (Thesis advisor) / Blattman, Joseph N (Committee member) / Langland, Jeffrey O (Committee member) / Stout, Valerie G (Committee member) / Arizona State University (Publisher)
Created2018
Description
Malignant brain tumors are devastating despite aggressive treatments such as surgical resection, chemotherapy and radiation therapy. The average life expectancy of patients with newly diagnosed glioblastoma is approximately 15 months. One novel therapeutic strategy involves using a ketogenic diet (KD) which increases circulating ketones and reduces circulating glucose. While the preclinical work has shown that the KD increases survival, enhances radiation and alters several pathways in malignant gliomas, its impact on the anti-tumor immune response has yet to be examined. This dissertation demonstrates that mice fed the KD had increased tumor-reactive innate and adaptive immune responses, including increased cytokine production and cytolysis via tumor-reactive CD8+ T cells. Additionally, we saw that mice maintained on the KD had increased CD4 infiltration, while T regulatory cell numbers stayed consistent. Lastly, mice fed the KD had a significant reduction in immune inhibitory receptor expression as well as decreased inhibitory ligand expression on glioma cells, namely programmed death receptor -1 (PD-1) and its ligand programmed death receptor ligand -1 (PD-L1). Further, it is demonstrated that the ketone body beta-hydroxybutyrate (BHB) reduces expression of PD-L1 on glioma cells in vitro suggesting it may be responsible in part for immune-related changes elicited by the KD. Finally this dissertation also shows that the KD increases the expression of microRNAs predicted to target PD-L1 suggesting a potential mechanism to explain the ability of the KD to modulate immune inhibitory checkpoint pathways. Taken together these studies shed important light on the mechanisms underlying the KD and provide additional support for its use an adjuvant therapy for malignant glioma.
ContributorsWoolf, Eric Christopher (Author) / Compton, Carolyn C. (Thesis advisor) / Scheck, Adrienne C (Committee member) / Preul, Mark C (Committee member) / Blattman, Joseph N (Committee member) / Mehta, Shwetal (Committee member) / Arizona State University (Publisher)
Created2018
Description
Zika virus (ZIKV) outbreaks have been linked to several neurological pathologies in the developing fetus, which can progress to spontaneous abortion and microcephaly in newborns whose mothers were infected with the virus during pregnancy. ZIKV has also been correlated with neurological complications in adults such as Guillain-Barré Syndrome (GBS). ZIKV outbreaks often occur in low income areas with limited access to healthcare. Therefore, there is a need to create a low-cost preventative vaccine against the virus. Mature ZIKV particles contain a lipid bilayer, a positive sense single stranded RNA genome and three structural proteins: the envelope (E), membrane (M) and capsid (C) proteins. Congruently, to other members of the Flaviviridae family, ZIKV proteins are synthesized as a polyprotein precursor which needs to be processed to release the mature structural and non-structural viral proteins. Past studies have determined the ZIKV precursor protein is cleaved by a host furin protease which separates the Pr peptide and the M protein, while the host signal peptidase separates the M and E protein. Processing is important for correct folding of the E protein. In turn, the most important neutralizing antibodies upon infection are directed against epitopes of the E protein. In this work, we used a Bean Yellow Dwarf Viral vector system to transiently express, in Nicotiana benthamiana plants, a portion of the ZIKV polyprotein encoding the Pr, M and E proteins. I further demonstrate that plants can proteolytically process the polyprotein to yield the two integral membrane proteins M and E. These proteins can be shown to co-partition into a soluble membrane-particulate fraction, consistent with formation of enveloped virus-like particles (VLPs). This work provides the first step in creating a low-cost sustainable plant-based production system of ZIKV VLPs that can be explored as a potential component 0f a low-cost prophylactic vaccine against ZIKV.
ContributorsDi Palma, Michelle Pina (Author) / Mor, Tsafrir S (Thesis advisor) / Mason, Hugh S (Committee member) / Blattman, Joseph N (Committee member) / Arizona State University (Publisher)
Created2018
Description
Glioblastoma (GBM) is a highly invasive and deadly late stage tumor that develops from abnormal astrocytes in the brain. With few improvements in treatment over many decades, median patient survival is only 15 months and the 5-year survival rate hovers at 6%. Numerous challenges are encountered in the development of treatments for GBM. The blood-brain barrier (BBB) serves as a primary obstacle due to its innate ability to prevent unwanted molecules, such as most chemotherapeutics, from entering the brain tissue and reaching malignant cells. The GBM cells themselves serve as a second obstacle, having a high level of genetic and phenotypic heterogeneity. This characteristic improves the probability of a population of cells to have resistance to treatment, which ensures the survival of the tumor. Here, the development and testing of two different modes of therapy for treating GBM is described. These therapeutics were enhanced by pathogenic peptides known to improve entry into brain tissue or to bind GBM cells to overcome the BBB and/or tumor cell heterogeneity. The first therapeutic utilizes a small peptide, RVG-29, derived from the rabies virus glycoprotein to improve brain-specific delivery of nanoparticles encapsulated with a small molecule payload. RVG-29-targeted nanoparticles were observed to reach the brain of healthy mice in higher concentrations 2 hours following intravenous injection compared to control particles. However, targeted camptothecin-loaded nanoparticles were not capable of producing significant treatment benefits compared to non-targeted particles in an orthotopic mouse model of GBM. Peptide degradation following injection was shown to be a likely cause for reduced treatment benefit. The second therapeutic utilizes chlorotoxin, a non-toxic 36-amino acid peptide found in the venom of the deathstalker scorpion, expressed as a fusion to antibody fragments to enhance T cell recognition and killing of GBM. This candidate biologic, known as anti-CD3/chlorotoxin (ACDClx) is expressed as an insoluble protein in Nicotiana benthamiana and Escherichia coli and must be purified in denaturing and reducing conditions prior to being refolded. ACDClx was shown to selectively activate T cells only in the presence of GBM cells, providing evidence that further preclinical development of ACDClx as a GBM immunotherapy is warranted.
ContributorsCook, Rebecca Leanne (Author) / Blattman, Joseph N (Thesis advisor) / Sirianni, Rachael W. (Thesis advisor) / Mor, Tsafrir (Committee member) / Anderson, Karen (Committee member) / Arizona State University (Publisher)
Created2019
Description
The HIV-1 pandemic continues to cause millions of new infections and AIDS-related deaths each year, and a majority of these occur in regions of the world with limited access to antiretroviral therapy. Therefore, an HIV-1 vaccine is still desperately needed. The most successful HIV-1 clinical trial to date used a non-replicating canarypox viral vector and protein boosting, yet its modest efficacy left room for improvement. Efforts to derive novel vectors which can be both safe and immunogenic, have spawned a new era of live, viral vectors. One such vaccinia virus vector, NYVAC-KC, was specifically designed to replicate in humans and had several immune modulators deleted to improve immunogenicity and reduce pathogenicity. Two NYVAC-KC vectors were generated: one expressing the Gag capsid, and one with deconstructed-gp41 (dgp41), which contains an important neutralizing antibody target, the membrane proximal external region (MPER). These vectors were combined with HIV-1 Gag/dgp41 virus-like particles (VLPs) produced in the tobacco-relative Nicotiana benthamiana. Different plant expression vectors were compared in an effort to improve yield. A Geminivirus-based vector was shown to increase the amount of MPER present in VLPs, thus potentially enhancing immunogenicity. Furthermore, these VLPs were shown to interact with the innate immune system through Toll-like receptor (TLR) signaling, which activated antigen presenting cells to induce a Th2-biased response in a TLR-dependent manner. Furthermore, expression of Gag and dgp41 in NYVAC-KC vectors resulted in activation of antiviral signaling pathways reliant on TBK1/IRF3, which necessitated the use of higher doses in mice to match the immunogenicity of wild-type viral vectors. VLPs and NYVAC-KC vectors were tested in mice, ultimately showing that the best antibody and Gag-specific T cell responses were generated when both components were administered simultaneously. Thus, plant-produced VLPs and poxvirus vectors represent a highly immunogenic HIV-1 vaccine candidate that warrants further study.
ContributorsMeador, Lydia Rebecca (Author) / Mor, Tsafrir S (Thesis advisor) / Jacobs, Bertram L (Thesis advisor) / Blattman, Joseph N (Committee member) / Mason, Hugh S (Committee member) / Arizona State University (Publisher)
Created2016
Description
The unique anatomical and functional properties of vasculature determine the susceptibility of the spinal cord to ischemia. The spinal cord vascular architecture is designed to withstand major ischemic events by compensating blood supply via important anastomotic channels. One of the important compensatory channels of the arterial basket of the conus medullaris (ABCM). ABCM consists of one or two arteries arising from the anterior spinal artery (ASA) and circumferentially connecting the ASA and the posterior spinal arteries. In addition to compensatory function, the arterial basket can be involved in arteriovenous fistulae and malformations of the conus. The morphometric anatomical analysis of the ABCM was performed with emphasis on vessel diameters and branching patterns.
A significant ischemic event that overcomes vascular compensatory capacity causes spinal cord injury (SCI). For example, SCI complicating thoracoabdominal aortic aneurysm repair is associated with ischemic injury. The rate of this devastating complication has been decreased significantly by instituting physiological methods of protection. Traumatic spinal cord injury causes complex changes in spinal cord blood flow (SCBF), which are closely related to a severity of injury. Manipulating physiological parameters such as mean arterial pressure (MAP) and intrathecal pressure (ITP) may be beneficial for patients with a spinal cord injury. It was discovered in a pig model of SCI that the combination of MAP elevation and cerebrospinal fluid drainage (CSFD) significantly and sustainably improved SCBF and spinal cord perfusion pressure.
In animal models of SCI, regeneration is usually evaluated histologically, requiring animal sacrifice. Thus, there is a need for a technique to detect changes in SCI noninvasively over time. The study was performed comparing manganese-enhanced magnetic resonance imaging (MEMRI) in hemisection and transection SCI rat models with diffusion tensor imaging (DTI) and histology. MEMERI ratio differed among transection and hemisection groups, correlating to a severity of SCI measured by fraction anisotropy and myelin load. MEMRI is a useful noninvasive tool to assess a degree of neuronal damage after SCI.
A significant ischemic event that overcomes vascular compensatory capacity causes spinal cord injury (SCI). For example, SCI complicating thoracoabdominal aortic aneurysm repair is associated with ischemic injury. The rate of this devastating complication has been decreased significantly by instituting physiological methods of protection. Traumatic spinal cord injury causes complex changes in spinal cord blood flow (SCBF), which are closely related to a severity of injury. Manipulating physiological parameters such as mean arterial pressure (MAP) and intrathecal pressure (ITP) may be beneficial for patients with a spinal cord injury. It was discovered in a pig model of SCI that the combination of MAP elevation and cerebrospinal fluid drainage (CSFD) significantly and sustainably improved SCBF and spinal cord perfusion pressure.
In animal models of SCI, regeneration is usually evaluated histologically, requiring animal sacrifice. Thus, there is a need for a technique to detect changes in SCI noninvasively over time. The study was performed comparing manganese-enhanced magnetic resonance imaging (MEMRI) in hemisection and transection SCI rat models with diffusion tensor imaging (DTI) and histology. MEMERI ratio differed among transection and hemisection groups, correlating to a severity of SCI measured by fraction anisotropy and myelin load. MEMRI is a useful noninvasive tool to assess a degree of neuronal damage after SCI.
ContributorsMartirosyan, Nikolay (Author) / Preul, Mark C (Thesis advisor) / Vernon, Brent (Thesis advisor) / Theodore, Nicholas (Committee member) / Lemole, Gerald M. (Committee member) / Vu, Eric (Committee member) / Arizona State University (Publisher)
Created2016