Medicine and Health Sciences Commons^™

Hypothalamic Circuits In The Control Of Feeding And Emotional Behaviors, Leandra Mangieri

Dissertations & Theses (Open Access)

Feeding results from the integration of both nutritional and affective states, and is guided by complex neural circuitry in the brain. The hypothalamus is a critical center controlling feeding and motivated behaviors. We found that targeted photostimulation of projections from the lateral hypothalamus (LH) to the paraventricular hypothalamus (PVH) in mice elicited voracious feeding and repetitive self-grooming behavior. GABA neurotransmission in the LH->PVH circuit mediated the evoked feeding behavior, and elicited behavioral approach, whereas glutamate release promoted repetitive self-grooming, which was stress-related in nature. Optogenetic inhibition of LH^GABA ->PVH circuit reduced feeding after fasting, whereas photostimulation abruptly …

Insights Into The Reactivation, Regulation And Essentiality Of Oxidative Protein Folding Pathways In Actinobacteria, Belkys Sanchez

Dissertations & Theses (Open Access)

Accurate disulfide bond formation is important for proper folding, stability and function of exported proteins. The process of disulfide bond formation, termed oxidative protein folding, is catalyzed by thiol-disulfide oxidoreductase enzymes. Oxidative protein folding pathways influence processes essential for bacterial physiology and pathogenicity. In the Gram-positive actinobacterial pathogens Actinomyces oris and Corynebacterium diphtheriae oxidative protein folding is catalyzed by the primary thiol-disulfide oxidoreductase MdbA. MdbA is required for assembly of adhesive pilus, which mediate receptor-dependent bacterial interactions, or coaggregation, in A. oris. In the first part of this dissertation, I identify components of the electron transport chain (ETC) required for …

Genetic Evolution And Prognostic Determinants Of Pancreatic Cancer On Longitudinal Liquid Biopsies, Vincent Bernard

Dissertations & Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) has one of the lowest 5-year survival rates amongst solid tumors. As early detection of PDAC is unusual and typically incidental, most patients present with locally advanced and metastatic disease where effective therapeutic strategies remain a significant unmet need. Specifically, surrogate biomarkers for tumor monitoring of PDAC may lead to improved elucidation of clinical actionability and prognostic potential. On the other hand, tumor tissue is rarely sampled in patients presenting with de novo or recurrent metastatic PDAC, apart from a fine needle aspiration or a core needle biopsy performed for diagnosis. This precludes the opportunity for …

Investigation Of Novel Virulence Mechanisms In Candida Albicans, Elisa Marie Tafoya Vesely

Dissertations & Theses (Open Access)

Candida albicans is the most important fungal species associated with humans. Normally present in the human microbiome as a commensal colonizer, C. albicans is also the fourth most prevalent organism isolated from bloodstream infections in hospitals. Disseminated infections have an associated mortality rate of around 40%. The results of the work described in this dissertation cover the broad subject of C. albicans adaptation to the host and the mechanisms by which this organism is able to survive and cause infection through a variety of means. A key determinant in disease progression is interaction with innate immune cells, specifically macrophages and …

A Role For Epac1 And Epac2 In Nociceptor Hyperexcitability And Chronic Pain After Spinal Cord Injury, Samantha Berkey

Dissertations & Theses (Open Access)

Chronic pain is a major complaint of those living with spinal cord injury (SCI), affecting 65-80% of the SCI population, but the treatment options remain limited or non-existent. The cAMP sensor EPAC has previously been shown to play a key role in chronic inflammatory and neuropathic pain, though the contribution from each of its two main isoforms, EPAC1 and EPAC2, is unclear. Here I test the hypothesis that both EPAC1 and EPAC2 play a key role in the maintenance of persistent nociceptor hyperexcitability and chronic pain after SCI.

Using both a T9 SCI mouse model and a T10 SCI rat …

Il-1Α Blockade Reduces Immune Suppression In The Early Tumor Micro-Environment, Brenda Melendez

Dissertations & Theses (Open Access)

IL-1α Blockade Reduces Immune Suppression in the Early Tumor Micro-Environment

Brenda Melendez, B.S.

Advisory Professor: Gregory Lizee, PhD.

Immunotherapy against melanoma has shown great promise in the clinic for treating advanced-stage patients. However, a major barrier against effective T cell mediated cytotoxicity is immunosuppression in the tumor micro-environment. It has been described that tumors secrete pro-inflammatory cytokines capable of modulating immune responses that favors the growth of tumor cells. Specifically, IL-1 plays a critical role in myeloid cell recruitment and activation, which can in turn inhibit T cell activity in vivo. Moreover, IL-1 is also known to up-regulate immune inhibitory …

Assembly And Display Of Surface Proteins In Actinomyces Oris, Sara Siegel

Dissertations & Theses (Open Access)

Bacteria are an integral part of human health and disease. In the human host, dental plaques form as a result of up to 700 individual bacterial species colonizing oral surfaces and forming a multispecies biofilm. These biofilms are the cause of prevalent human diseases such as dental caries, gingivitis, and periodontitis. The microbes present in the oral biofilm are highly spatially and temporally structured and require a primary colonizing species to adhere to host tissue. As an important primary colonizer of the oral biofilm, the actinobacterium Actinomyces oris utilizes cell wall anchored proteins and glycoconjugates to initiate adherence to host …

Investigating The Single Cell Heterogeneity And Physiological Impact Of Mistranslation, Christopher Evans

Dissertations & Theses (Open Access)

Bacterial populations grow clonal populations; however, individual cells have a variety of phenotypes. The physiological heterogeneity observed in populations has been attributed to variations in the processes of gene expression. For example, promoter expression has been shown to be heterogeneous within a population and contribute to increased stress tolerance in a subpopulation of cells. In comparison to transcription, the influence of translation on single cells is unclear. In this study, my collaborators and I have developed a dual-fluorescence reporter that allows us to measure the mistranslation rate in single cells in vivo. Using this reporter, we found that mistranslation …

Behavioral Insights Into Nociceptor Function: A Systematic Approach To Understanding Postsurgical And Neuropathic Pain Mechanisms In Rats, Max Odem

Dissertations & Theses (Open Access)

Postsurgical and neuropathic pain are each clinically common, and often associated with ongoing pain. Ongoing pain has been linked to ongoing activity (OA) in human C-fiber nociceptors. Preclinical studies using rodent neuropathic models have concentrated on allodynia driven by OA generated in non-nociceptive Aβ fibers, but little attention has been paid to postsurgical pain in sham controls or to C-fiber nociceptor OA promoting ongoing pain.

Operant assays that reveal negative motivational and cognitive aspects of voluntary pain-related behavior may be particularly sensitive to pain-related alterations. In the mechanical conflict (MC) test, rodents can freely choose to escape from a brightly …

Targeting Ph Domain Proteins For Cancer Therapy, Zhi Tan

Dissertations & Theses (Open Access)

Targeted therapy has been one of the most promising treatment options for cancer during the past decade. Discoveries of potent and selective small molecule inhibitors are critical to new and promising targeted therapy. Pleckstrin Homology (PH) domain proteins are one of the biggest protein families in the human proteome. However, no drugs have been achieved to the late development stages, let alone getting to the market. Thus, a deeper understanding of this protein family is required and there is an urgent need to develop novel small molecule compounds targeting these proteins.

Studies of PH domains began around two decades ago …

The Role Of Tumor Suppressor Dear1 In The Acquisition Of Mammary Stem/Progenitor Cell Properties, Uyen Le

Dissertations & Theses (Open Access)

Breast cancer is the most commonly diagnosed cancer in women in America. Ductal carcinoma in situ (DCIS), one of the earliest pre-invasive forms of invasive ductal carcinoma (IDC), has a 30-50% risk of progressing to IDC. Understanding the mechanisms regulating progression from DCIS to IDC would help identify biomarkers to stratify patients at higher risk of progression or metastasis. Cumulative literature suggests the earliest phase of dissemination from the primary tumor is driven by the epithelial-mesenchymal transition (EMT) program. DEAR1 is a tumor suppressor gene which is mutated, undergoes loss of heterozygosity in breast cancer, and is downregulated in DCIS …

Ontology-Based Clinical Information Extraction Using Snomed Ct, Jun Li

Dissertations & Theses (Open Access)

Extracting and encoding clinical information captured in unstructured clinical documents with standard medical terminologies is vital to enable secondary use of clinical data from practice. SNOMED CT is the most comprehensive medical ontology with broad types of concepts and detailed relationships and it has been widely used for many clinical applications. However, few studies have investigated the use of SNOMED CT in clinical information extraction.

In this dissertation research, we developed a fine-grained information model based on the SNOMED CT and built novel information extraction systems to recognize clinical entities and identify their relations, as well as to encode them …

Comparing Attributional And Relational Similarity As A Means To Identify Clinically Relevant Drug-Gene Relationships, Safa Fathiamini

Dissertations & Theses (Open Access)

In emerging domains, such as precision oncology, knowledge extracted from explicit assertions may be insufficient to identify relationships of interest. One solution to this problem involves drawing inference on the basis of similarity. Computational methods have been developed to estimate the semantic similarity and relatedness between terms and relationships that are distributed across corpora of literature such as Medline abstracts and other forms of human readable text. Most research on distributional similarity has focused on the notion of attributional similarity, which estimates the similarity between entities based on the contexts in which they occur across a large corpus. A relatively …

The Role Of Perivascular Fibrosis In Post-Stroke Glymphatic Impairment And Cerebral Amyloid Angiopathy, Matthew D. Howe

Dissertations & Theses (Open Access)

In healthy brain tissue, toxic amyloid-β (Aβ) proteins are transported by the pulsatile flow of cerebrospinal fluid (CSF) along perivascular drainage pathways. Ischemic stroke may disrupt this process, leading to a perivascular build-up of Aβ, termed cerebral amyloid angiopathy (CAA). I hypothesize that an abnormal pattern of extracellular matrix deposition within the vascular basement membrane, termed fibrosis, impairs Aβ drainage from the aged brain after stroke. I further hypothesize that inhibition of astrocytic transforming growth factor-β (TGF-β) signaling can reverse these phenotypes. Finally, I also hypothesize that serum biomarkers of perivascular fibrosis can be used to diagnose CAA following intracerebral …

Omics Approaches To Uncover Germline And Somatic Variation Underlying Inherited Sarcomagenesis, Justin Wong

Dissertations & Theses (Open Access)

Sarcomas are rare mesenchymal tumors, making up 15% of all childhood and 1% of all adult tumors. They account for a disproportionate share of mortality in young adults, and if left untreated, are highly likely to metastasize. However, sarcoma etiology is poorly understood, and having numerous histological subtypes has complicated elucidation. To better understand factors underlying sarcomagenesis, we leveraged two rare inherited cancer predisposition syndromes, Li-Fraumeni Syndrome (LFS), and LFS-like (LFSL), both with a high incidence of sarcomas. LFS is caused by mutations in the tumor suppressor gene TP53 (p53), but has variable and incomplete penetrance, suggesting additional acquired …

Genomic And Transcriptomic Landscape Of Colorectal Premalignancy, Kyle Chang

Dissertations & Theses (Open Access)

Colorectal cancer (CRC) is the third most commonly diagnosed cancer among men and women in the United States, with 3 to 5 percent of the cases diagnosed in the background of a hereditary form of the disease. Biologically, CRC is divided into two groups: microsatellite instable (MSI) and chromosomally unstable (CIN). Genomic and transcriptomic characterization of CRC has emerged from large-scale studies in recent years due to the advancement of next-generation sequencing technologies. These studies have identified key genes and pathways altered in CRC and provided insights to the discovery of therapeutic targets. Despite the wealth of knowledge acquired in …

Ube4b Levels Determine The Efficacy Of Egfr And Stat5 Inhibitors In Treatment Resistant Neuroblastoma, David James Savage

Dissertations & Theses (Open Access)

Neuroblastoma is the most common malignancy in infants. Overexpression of the epidermal growth factor receptor (EGFR) in neuroblastoma tumors can result in enhanced EGFR signaling, uncontrolled proliferation, and may provide a mechanism for chemotherapy resistance. UBE4B, an E3/E4 ubiquitin ligase, ubiquitinates the EGFR and promotes its lysosomal degradation ultimately attenuating EGFR signaling. Interestingly, the UBE4B gene lies in a chromosomal region (1p36) whose loss is correlated with poor patient outcomes due to inefficient EGFR degradation and enhanced cell proliferation. We examined whether depletion of UBE4B in a chemoresistant neuroblastoma cell line would affect tumor responses to drugs that specifically target …

Investigating The Roles Of Tap63 And Tap73 In Cutaneous Squamous Cell Carcinoma And Lung Adenocarcinoma, Andrew J. Davis

Dissertations & Theses (Open Access)

TP63 and TP73 (which encode p63 and p73, respectively) are highly conserved transcription factors with important roles in development and tissue homeostasis. Similar to their homolog, p53, both p63 and p73 have been shown to mediate tumor suppression in multiple tissue types. Interestingly, however, both genes are expressed as multiple isoforms, which appear to have different and, in many cases, antagonistic functions. Through the use of isoform-specific null alleles of p63 and p73 our lab and others have shown that the full-length N-terminal isoforms of p63 and p73 (referred to as TAp63 and TAp73, respectively) exhibit distinct functions in development, …

Ischemic Stroke Damage Is Reduced By Inhibition Of Il-6 Signaling With Tocilizumab, Jacob Hudobenko

Dissertations & Theses (Open Access)

Introduction:

Stroke is the leading cause of serious long-term disability and is the 5^th leading cause of death causing approximately 130,000 deaths in the United States every year {1}. Stroke is also the 2^nd leading cause of death in American women {2}. Women are 33% more likely to require nursing home care then men, have a higher lifetime risk of stroke and are 13% less likely to receive thrombolytic (clot busting) treatment than men {2}. Interleukin 6 (IL-6) is a pro-inflammatory cytokine involved in the regulation of the immune system in multiple disease states such as rheumatoid …

Simvastatin Does Not Sensitize Ibc3 Her2+ Inflammatory Breast Cancer Brain Metastases To Whole Brain Irradiation In An Immunocompromised Mouse Model, Swaminathan Kumar

Dissertations & Theses (Open Access)

Retrospective data analysis suggests that inflammatory breast cancer (IBC) patients who take statins have better locoregional control after radiotherapy than those who do not [23]. Our lab has previously demonstrated that simvastatin radiosensitizes IBC cells in vitro [23], and brain metastases have strong expression of cholesterol-regulation genes compared to lung metastases in vivo [unpublished]. Delaying whole-brain irradiation (WBI) beyond 21 days is insufficient to reduce the incidence of brain metastases (developed by injecting IBC3 cells through the tail vein) in our mouse model because even high rates of cell killing leave substantial cell volume in established metastases [unpublished].

With the …

Microrna Functions In Uv-Induced Cutaneous Squamous Cell Carcinoma, Tran Nguyen

Dissertations & Theses (Open Access)

Cutaneous squamous cell carcinoma (cuSCC) is the second most common skin cancer, for which long term UV exposure and chronic wounding are the dominant risk factors. Despite these clinically established connections, little is understood about the early molecular response of human skin to UV exposure and its connection to acute wounding and cuSCC. Thus, our goal is to find common and specific signatures driven by UV-exposure and wounding as a means of developing new approaches for treating and preventing cuSCC.

Here, we perform integrated analyses of RNA-seq and miR-seq on 3 datasets: (1) UV-unexposed and acute UV-exposed human skin, (2) …

Characterizing The Recognition Motif And Novel Substrates Of Carm1, Sitaram Gayatri

Dissertations & Theses (Open Access)

A limited pool of proteins attains vast functional repertoire due to posttranslational modifications (PTMs). Arginine methylation is a common posttranslational modification, which is catalyzed by a family of nine protein arginine methyltransferases or PRMTs. These enzymes deposit one or two methyl groups to the nitrogen atoms of arginine side-chains. Elucidating the substrate specificity of each PRMT will promote a better understanding of which signaling networks these enzymes contribute to. Although many PRMT substrates have been identified, and their methylation sites mapped, the optimal target motif for each of the nine PRMTs has not been systematically addressed. Here we describe the …

Dissecting The Molecular Mechanism Of Early Tumor Dissemination In Non-Small Cell Lung Cancer, Xingtong Liu

Dissertations & Theses (Open Access)

Lung cancer is the most common cause of cancer related death in the United States and worldwide. It has been shown that 30%-55% of patients with early stages of non-small cell lung cancer (NSCLC) developed and died of recurrence after curative resection, suggesting that tumor cell dissemination occurred early in those patients before surgery. However, molecular evidence, underline mechanisms and risk factors for the NSCLC relapse remain largely unknown. Addressing these questions will be critical for the development of strategies to stratify the risk of recurrence and approaches to reduce these risks. My thesis focused on dissecting the molecular basis …

The Role Of Merlin And Apicobasal Polarity In Endometrial Development And Homeostasis, Erin Lopez

Dissertations & Theses (Open Access)

Apicobasal polarity and cell adhesion are necessary for the proper formation and organization of epithelial tissues. Merlin couples cell polarity and adhesion through correct localization of the polarity protein Par3 and maturation of apical junctions. Merlin and Par3 are necessary for the development and homeostasis of highly regenerative tissues like the epidermis. The continual repopulation of the endometrium after each menstrual cycle requires a constant reorganization of cell polarity and adhesion. The endometrium consists of a luminal epithelium that postnatally gives rise to the distinct glandular epithelium. Endometrial glands are necessary to secrete nutrients for the pre-implantation embryo. In addition, …

Functional Heterogeneity Of Fibroblasts In Dermal Wound Healing, Ehsan Ehsanipour

Dissertations & Theses (Open Access)

Impaired wound healing can lead to excessive scarring, dehiscence, chronic ulcers, and infection, which have adverse impact on the quality of life and pose a significant economic burden on the health care system. Thus, new therapeutic approaches are critically important. Dermal fibroblasts are critical players in cutaneous wound healing, possibly lending their contractile properties and extracellular matrix (ECM) remodeling functions to promote effective tissue repair. Dermal fibroblasts are also postulated to orchestrate tissue repair by interacting with and controlling other cell types in the wound microenvironment. It has become increasingly clear that the generic term “fibroblast” encompasses a diverse cell …

Trim24 As An Oncogene In The Mammary Gland, Aundrietta Duncan

Dissertations & Theses (Open Access)

Despite the many advances made in breast cancer research and treatments, breast cancer remains one of the deadliest diseases plaguing women worldwide. While many findings on genetic mutations and their role in predisposing people to breast cancer have been uncovered, we are just beginning to understand the extent to which epigenetic regulators promote tumorigenic phenotypes, metastasis, and chemotherapeutic resistance. Moreover, new experimental tools offer the ability to address questions we were previously unable to assess. My project takes advantage of a new mouse model to understand the role of a proto-oncogenic, transcriptional co-regulator, TRIM24, in mammary gland development and disease. …

Computational Insights Into The Generation Of Chromosomal Copy Number Changes, Yihua Liu

Dissertations & Theses (Open Access)

Deviations from a diploid configuration of the human genome, spanning single genes or entire chromosomes, can have wide-ranging impacts on the variation of human phenotypes, including Mendelian and complex forms of diseases. These chromosomal alterations — such as duplications, deletions or copy-neutral loss-of-heterozygosity — are thus important forms of genetic variation for phenotyping populations of individuals as well as populations of cells. Indeed, copy number variants (CNVs) serve as hallmarks of critical changes in the development of particular diseases such as cancer and thus may be used as biomarkers. These CNVs may be either inherited (transmitted by germ cells, originating …

Investigating Invasion In Ductal Carcinoma In Situ With Topographical Single Cell Genome Sequencing, Anna Casasent, Anna Casasent

Dissertations & Theses (Open Access)

Synchronous Ductal Carcinoma in situ (DCIS-IDC) is an early stage breast cancer invasion in which it is possible to delineate genomic evolution during invasion because of the presence of both in situ and invasive regions within the same sample. While laser capture microdissection studies of DCIS-IDC examined the relationship between the paired in situ (DCIS) and invasive (IDC) regions, these studies were either confounded by bulk tissue or limited to a small set of genes or markers. To overcome these challenges, we developed Topographic Single Cell Sequencing (TSCS), which combines laser-catapulting with single cell DNA sequencing to measure genomic copy …

Mechanisms And Targeting Of Neurodevelopmental Regulator Rest In Medulloblastoma Dissemination, Keri Callegari

Dissertations & Theses (Open Access)

Molecular subgrouping of medulloblastoma (MB) has produced four subgroups: wingless (WNT), sonic hedgehog (SHH), group 3, and group 4. While patients with WNT tumors have the best prognosis, patients with SHH tumors have a more variable prognosis concurrent with metastatic disease. This subset of SHH patients have elevated levels of the neurogenic regulator, RE1 Silencing Transcription factor (REST). To understand the role of REST in MB, we utilized a novel transgenic mouse model wherein REST expression can be conditionally elevated during postnatal development in the cells of origin of SHH MB, cerebellar granule neural progenitors (GNPs). While these mice did …

Structure Based Drug Design Of High Affinity Kras Inhibitors, Michael Mccarthy

Dissertations & Theses (Open Access)

RAS, one of the most well characterized membrane-associated small GTPases, is a notorious oncogene with >15% of all tumors harboring RAS mutations. When RAS is mutated it becomes constitutively active sending cell growth, survival and proliferation into overdrive, which subsequently leads to cancer. Although, RAS has been aggressively targeted with drug design efforts for more than 30 years an FDA approved direct inhibitor has not yet been developed. There are three isoforms of RAS in cells; HRAS, NRAS and KRAS. We focused on KRAS since it is the most frequently mutated isoform in cancer. To identify novel non-covalent small molecules …