Medical Sciences Commons^™

Studies On The Leukocyte-Associated Ig-Like Inhibitory Receptor-1 Signaling Pathway In T Lymphocytes, Chidi Zacheaus

Theses and Dissertations (ETD)

Inflammation is a natural process in which the immune system concertedly responds to pathogens and abnormal cell growth to protect the host. For an efficient/effective immune response that circumvents tissue atrophy, a delicate balance between stimulatory and inhibitory mechanisms is essential for the proper functioning of the immune system. Immuno-receptor Tyrosine-based Inhibitory Motif (ITIM)-bearing receptors in immune cells, including T lymphocytes, play a major role in preventing autoimmune responses. Leukocyte-associated Ig-like Inhibitory Receptor 1 (LAIR-1) is one of ITIM-bearing receptors. The mechanism by which LAIR-1 attenuates T-cell response has yet to be completely understood. In this study, I investigated a …

Physiologically-Based Pharmacokinetic (Pbpk) Modeling For The Preclinical Development Of Spectinamide Antibiotics, Keyur R. Parmar

Theses and Dissertations (ETD)

Despite being an ancient disease caused by Mycobacterium tuberculosis (Mtb) and after decades of research, tuberculosis (TB) still affects millions of people every year worldwide. In 2018, the World Health Organization (WHO) reported that 10 million people developed tuberculosis and 1.5 million died of the disease. With the increase in the multidrug-resistant (MDR) and extensively drug-resistant (XDR) cases, the treatment for TB with the standard first and second-line therapy is becoming increasingly difficult. Therefore, there is an urgent need to find new anti-TB drugs as combination partners of existing and experimental classes of antimicrobial agents to shorten and simplify the …

Computer-Aided Drug Discovery For Helicobacter Pylori, Nicole Ann Vita

Theses and Dissertations (ETD)

Helicobacter pylori is a high-priority drug-resistant pathogen and is currently the only bacteria considered to be a class I carcinogen and there is a critical need to identify novel chemical matter to treat H. pylori infections. Hp is responsible for greater than 60% of gastric cancer related deaths and 89% of all gastric cancer morbidities. In a previous study, our lab identified novel Hp thienopyrmidine inhibitors that target respiratory complex I, an essential enzyme in respiration. Respiratory complex I is a large asymmetric multidomain and membrane bound enzyme and due to these innate features, it is not practical for biophysical …

Targeting Myeloid Protein Kinase C Signaling To Overcome Immune Suppression And Improve Immunotherapy In Cancer, Mehdi Chaib

Theses and Dissertations (ETD)

Checkpoint immunotherapy unleashes T cell antitumor potential which has revolutionized cancer treatment showing unprecedented long-term responses. However, most patients do not respond to immunotherapy which often correlates with a dysfunctional or immunosuppressive myeloid compartment. Immunosuppressive myeloid cells comprise Myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) and can suppress T cells via production of immunosuppressive factors. Conversely, efficient cytotoxic T cell priming is dependent on the ability of antigen-presenting cells (APCs), mainly conventional dendritic cells (cDCs) and macrophages, to present or cross-present tumor antigens to T cells. Thus, targeting immunosuppressive myeloid cells while simultaneously enhancing APCs represents a promising strategy …

Characterizing And Overcoming Resistance To Aminomethylspectinomycins In Gram-Negative Bacteria, Nisha Das

Theses and Dissertations (ETD)

Spectinomycin (SPC) is a broad-spectrum aminocyclitol antibiotic. Its use in agriculture has led to widespread resistance in enteric bacteria, necessitating the development of more effective analogs. Aminomethyl spectinomycins (amSPC) are modified spectinomycins with increased potency against many bacterial species. These species include Legionella pneumophila, which harbors a chromosomally encoded aminoglycoside modifying enzyme (AME). In this study, we follow up on this observation and examine the extent to which the amSPCs are substrates for AMEs through adenylation (ANTs) and phosphorylation (APH). APH(9)-Ia and ANT(3")(9) were expressed in E. coli BL21(DE3) and purified using the Ni-affinity chromatography. The ability of AMEs to …

Antibiotic Tolerance And Heteroresistance: Associated Fitness Costs And Potential In Evading Antibiotic Killing, Tina H. Dao

Theses and Dissertations (ETD)

Streptococcus pneumoniae is a prominent human pathogen that causes both invasive and non-invasive diseases, such as otitis media, pneumonia, meningitis, and bacteremia. Although it is frequently an asymptomatic colonizer of the human nasopharynx, S. pneumoniae is a major cause of morbidity and mortality in the immune compromised population, young children, and the elderly. Up until the 1970s, S. pneumoniae was susceptible to almost all antibiotics. Since then, this pathogen has gained resistance to a variety of antibiotic treatments, including beta-lactams, macrolides, and fluoroquinolones.

In the first chapter, we focused on fluoroquinolone resistance in S. pneumoniae. Fluoroquinolones are one of the …

Muc13 Enhances Colorectal Cancer Metastasis, Kyle Doxtater

Theses and Dissertations (ETD)

Colorectal cancer (CRC) is one of the most prevalent cancer worldwide with a 5% lifetime incidence in developed countries. It is third most common cause of cancer related death in the United States and the second deadliest when men and women are combined. Encouragingly due to changes in dietary lifestyle, screening colonoscopy, and advancement in treatments the mortality has decreased in recent years. Most sporadic CRCs develop from polyploid adenomas and are preceded by intramucosal carcinomas (stage 0), which can progress into more malignant forms. This developmental process is known as the adenoma-carcinoma sequence. Early detection and endoscopic removal are …

Genetic Mechanisms Of Transcriptional Regulation In Childhood Acute Lymphoblastic Leukemia, Xujie Zhao

Theses and Dissertations (ETD)

Introduction. Advances in genomic profiling and sequencing studies have identified germline and somatic variations that are associated with childhood ALL, improving our understanding of the genetic basis of childhood acute lymphoblastic leukemia (ALL). Recent genome-wide association studies (GWAS) have identified germline genetic variations of ARID5B and, more recently, IGF2BP1 that are associated with susceptibility to ALL. Genome-wide sequencing studies also discovered a new ALL subtype characterized of ZNF384-mediated chromosomal translocations, providing new insights into genetic heterogeneity in childhood ALL. However, the underlying mechanism by which these genetic variants contribute to the transcriptional regulatory circuitries of ALL is still poorly understood. …

Vitamin D Levels Affect Survival In A Bcr-Abl Acute Lymphoblastic Leukemia Mouse Model But Do Not Cause Vitamin-Drug Interactions, Kavya Annu

Theses and Dissertations (ETD)

It is a well-established phenomenon that dietary components containing CYP3A inducers or inhibitors if co-administered with drugs that are CYP3A4 substrates lead to marked drug-drug interactions. Because vitamin D is known to regulate intestinal CYP3A expression and gut CYP3A expression plays an important role in pre-systemic metabolism of CYP3A drugs, we determined the impact of vitamin D (VD3) status on systemic exposure and efficacy of chemotherapeutic agents that are CYP3A substrates. We employed VD3 sufficient and deficient mice to perform pharmacokinetics (PK) and anti-leukemic efficacy studies.

First, using hCYP3A4 transgenic mouse model we evaluated the intestinal, hepatic and renal expression …

Veru-111 As An Oral Tubulin Inhibitor Suppressing Triple-Negative Breast Cancer And Evaluation Of Novel Tubulin Inhibitors For Cancer Therapy, Shanshan Deng

Theses and Dissertations (ETD)

Triple negative breast cancer (TNBC) has aggressive clinical features strongly associated with poorer overall prognosis and higher mortality rates relative to other molecular subtypes. FDA-approved drugs, such as paclitaxel, are effective in treating TNBC. Yet, treatment failure is commonly observed due to the development of acquired chemoresistance, which remains a clinical challenge for TNBC therapy.

Validation And Application Of A Novel Target-Based Whole-Cell Screen To Identify Antifungal Compounds, Christian Alexander Dejarnette

Theses and Dissertations (ETD)

Traditional approaches to drug discovery are inefficient and have several key limitations that constrain our capacity to rapidly identify and develop novel experimental therapeutics. To address this, we have devised a second-generation target-based whole-cell screening assay based on the principles of competitive fitness, which can rapidly identify target-specific and physiologically-active compounds. Briefly, strains expressing high, intermediate, and low levels of a preselected target protein were constructed, tagged with spectrally distinct fluorescent proteins (FPs), and mixed together. The pooled strains were then grown in the presence of various small molecules, and the relative growth of each strain within the mixed culture …

Novel Determinants That Influence Azole Susceptibility In Candida Glabrata And Candida Albicans, Sarah Garland Whaley

Theses and Dissertations (ETD)

Despite the scientific and medical communities’ best efforts, the incidence of fungal infections in susceptible populations continues to rise. The most common cause of these opportunistic fungal infections is Candida. In fact, Candida is the fourth most common pathogen associated with nosocomial blood stream infections. Reported mortality rates for patients with candidemia vary, but have not decreased in the past fifteen years and are reported to be as high as 50%. Candida glabrata, second only to Candida albicans among Candida infections, expresses high rates of resistance to treatment with arguably the best class of currently available antifungals - …

Somatic Mutation Detection In Leukemia-Derived Circulating Dna: Utility In Monitoring Clonal Dynamics And Disease Response In Pediatric Acute Lymphoblastic Leukemia, Sarah Hisham Abdelaziz Youssef

Theses and Dissertations (ETD)

Despite the improved outcome associated with current treatment strategies ofpediatric acute lymphoblastic leukemia (ALL), relapse still represents a major challenge. Pediatric ALL demonstrates branched evolution in response to selective pressure exerted by therapy; relapse founder clones emerge from pre-leukemic clones or minor subclones present at diagnosis. It is hence crucial to develop biomarkers capable of tracking subclones throughout therapy. Current practices for monitoring disease response in leukemia rely on the analysis of BM biopsy sample at specific time points throughout therapy. Not only the invasiveness of the BM biopsy hinders the sequential sampling, but also, the currently implied techniques are …

Characterization Of The Hepatotoxicity Of Rifampicin And Isoniazid, Christopher T. Brewer

Theses and Dissertations (ETD)

In a mouse model, rifampicin and isoniazid combination treatment results in cholestatic liver injury that is associated with an increase of protoporphyrin ix (PPIX), the penultimate heme precursor. Excess PPIX is believed to bind to bile acids, precipitate in bile canaliculi, and form bile plugs leading to cholestasis fol owed by liver injury. Both ferrochelatase (FECH/Fech) and aminolevulinic acid synthase 1 (ALAS1/Alas1) are crucial enzymes in regulating heme biosynthesis. Isoniazid has recently been reported to up-regulate Alas1 but down-regulate Fech protein levels in mice; however the mechanism of isoniazid mediated heme synthesis …

Cannabinoid Receptor 2 (Cb2) Ligands Downregulate Pro-Inflammatory Markers In Stimulated Primary Human Periodontal Ligament Fibroblasts (Hpdlfs), Ammaar Hasan Abidi

Theses and Dissertations (ETD)

There are approximately 743 million individuals suffering from chronic periodontitis (PD) making it the sixth most prevalent condition worldwide. The affected adult population in the U.S. are nearly 64.7 million and the healthcare costs exceeds $14 billion. Recently, host response to pathogenic infection has been seen critical to the progression of PD and exhibit increase in various inflammatory markers. Marijuana is well known for its recreational usage and is a risk factor for periodontal disease, which is seen as a concern in society for its negative health consequences. However, many medical conditions can benefit from the pharmacological effects of cannabinoids. …

Regulation Of Cancer Metastasis By Protein Kinase D1: A Global Regulatory Cascade, Aditya Ganju

Theses and Dissertations (ETD)

Protein Kinase D1 (PKD1) is a serine threonine kinase which is downregulated in Prostate, Breast and Colon Cancer. It functions as a tumor suppressor in different cancer cells. Downregulation of PKD1 is known to be associated with aggressiveness of the cancer. PKD1 is known to regulate many key oncogenic signaling pathways such as E-cadherin, β-catenin and Androgen Receptor signaling pathways. Aberrant expression of these oncogenic pathways leads to transformation of cells from normal to malignant phenotype, thereby leading to increased proliferation, growth and metastasis to distant organs of these cancer cells. Literature evidence also points to the fact that E-cadherin …

Repeated Zolpidem Treatment Effects On Sedative Tolerance, Withdrawal, Mrna Levels, And Protein Expression, Brittany T. Wright

Theses and Dissertations (ETD)

Zolpidem and benzodiazepines (BZs) potentiate the inhibitory action of gamma-Aminobutyric acid (GABA) by allosterically binding to GABAA receptors (GABAAR). Prolonged use of GABAAR positive allosteric modulators (PAM) can lead to behavioral tolerance, the diminished response to the same drug dose with repeated use, and withdrawal, a group of symptoms that occur due to abrupt end of drug treatment. Zolpidem is a short-acting, non-BZ GABAAR PAM whose potential for tolerance and withdrawal is unclear. Zolpidem demonstrates sedative efficacy similar to BZs and has become a main treatment of insomnia in lieu of BZs. Zolpidem replaced BZs due to lower incidences of …

Hit Identification For Pkcζ Inhibitors: Structure-Based Optimization, Virtual Screening, And Biological Evaluation, Xiaoxin Wu

Theses and Dissertations (ETD)

Protein kinase C ζ (PKCζ) is believed to be a promising target for the treatment of some diseases, including inflammatory diseases, obesity and diabetes. Hit identification of PKCζ inhibitors was conducted by structure-based modification, virtual screening and biological evaluation. Among all the compounds selected and synthesized, compound JW-1-60A showed moderate activity against PKCζ at 30 μM and 100 μM. The molecular modeling studies showed that the binding mode of JW-1-61A was very close to the binding mode of JP-3-149, a reported PKCζ inhibitor with very potent activity, which might partially explain the moderate activity of JW-1-61A. Based on the structure …

Development Of Oral Vaccines Against Lyme Disease, Rita Raquel Dos Anjos De Carvalho E Melo

Theses and Dissertations (ETD)

Lyme Disease, caused by the spirochete Borrelia burgdorferi, is the most common vector-borne disease in the United States and Europe. If left untreated, it can lead to permanent damage to the nervous and musculoskeletal systems. In some cases, patients that receive the recommended antibiotic therapy develop a debilitating health condition associated with substantial health care costs. Despite current preventive measures, the incidence and the geographic distribution of Lyme Disease continues to increase. Recent estimates from CDC suggest that the true number of cases of Lyme Disease in the US is approximately 300,000 per year. Yet, there is currently no vaccine …

Development And Evaluation Of Amphotericin B Loaded Iron Oxide Nanoparticles For Targeted Drug Delivery To Systemic Fungal Infections, Pavan Balabathula

Theses and Dissertations (ETD)

A targeted nanotheronostic drug delivery system to diagnose and treat life threatening invasive fungal infections (IFIs) such as cryptococcal meningitis was designed, developed, characterized, and evaluated. To address the development processes, first, iron oxide nanoparticles (IONP) (34-40 nm) coated with bovine serum albumin (BSA), loaded and targeted with amphotericin B (AMB) (AMB-IONP) was formulated by applying a layer by layer approach. Several designs (A, B, C, D, & E) of AMB-IONP were developed and their physicochemical properties such as drug loading with HPLC method, particle size, poly dispersity index (PDI), and ζ-potential using dynamic light scattering (DLS) technique, morphology with …

Erg11-Mediated Azole Resistance In Candida Albicans, Stephanie Ann Flowers

Theses and Dissertations (ETD)

Although many medically important Candida species are commensal to the gut or colonizers of the skin, these organisms have the propensity to cause disease in the event of a waning immune system. Clinical manifestations of infections with Candida species can range from superficial mucosal infections to deep organ involvement usually resulting from haematogenous spread of infection. Despite significant progress made in the management of patients with fungal infections, the emergence of antifungal resistant clinical isolates creates significant problem in regards to antifungal prophylaxis and empirical treatment strategies. Antifungal resistance is associated with high mortality rates and hefty medical costs. The …

Attenuation Of Parenteral Nutritionassociated Liver Disease By Omega-3 Long-Chain Polyunsaturated Fatty Acids, Emma Monique Tillman

Theses and Dissertations (ETD)

No abstract provided.

Discovery Of Dihydroartemisinin And Dasatinib Drug Combination To Cure Pooroutcome Bcr-Abl+ Acute Lymphoblastic Leukemia, Harpreet Singh

Theses and Dissertations (ETD)

Oncogenic signaling by the Philadelphia chromosome-encoded BCR-ABL fusion kinase initiates and drives both Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) and chronic myelogenous leukemia (CML). Food and Drug Administration (FDA)- approved BCR-ABL-specific kinase inhibitors (BCR-ABL–KIs) imatinib, dasatinib and nilotinib induce prolonged remissions in CML but poor leukemia-reduction and relapse-control in Ph+ ALL. The relative primary BCR-ABL–KI-resistance in Ph+ ALL patients carrying predominantly BCR-ABLWT disease cannot be attributed to drug-resistant BCR-ABL mutations (BCR-ABLMUTANTS), and remains poorly understood.

We established a cell-based platform to evaluate the modulation of anti-Ph+ ALL activity of drugs by both tumor-extrinsic cytokines normally present in the leukemia …

Tamoxifen: Mechanisms Of Resistance, Cyrus Mccoy Adams

Theses and Dissertations (ETD)

The role of estrogen in breast cancer has been recognized for decades. The selective estrogen receptor modulator tamoxifen was the first targeted therapy for the treatment of breast cancer. It was also the first drug approved by the FDA for the reduction of breast cancer risk. While tamoxifen has extended the lives of countless patients with breast cancer, resistance to tamoxifen remains a significant clinical problem. Work over the last two decades has greatly enhanced our understanding of the molecular mechanisms by which breast cancer cells may become resistant to tamoxifen treatment. Here I review our current understanding of the …

Design, Synthesis, And Evaluation Of Small Molecules In The Discovery Of Novel Antimicrobial Agents, Kimberly D. Grimes

Theses and Dissertations (ETD)

The increasing prevalence of antibiotic-resistant bacteria, including Mycobacterium tuberculosis, Streptococcus pneumoniae, Staphylococcus aureus, and Enterococcus faecalis, pushes us to discover new antibacterial agents to maintain adequate patient coverage. This body of work highlights the use of medicinal chemistry methodologies that encompass cross-disciplinary fields of study. Chapter 1 gives an introduction to the antibacterial drug targets, resistance, and how scientists are working to overcome obstacles encountered with drug-resistant bacteria. It also details modern medicinal chemistry applications in antimicrobial drug discovery. Chapter 2 details the use of a structure-guided library approach to drug design, in which large virtual libraries against the target …

Role Of Medial Prefrontal Cortical Group Ii Metabotropic Glutamate Receptor In The Development Of Cocaine Sensitization, Xiaohu Xie

Theses and Dissertations (ETD)

The current studies examined the role of medial prefrontal cortical (mPFC) group II metabotropic glutamate receptors (mGluR_2/3) in the development of cocaine sensitization. Initial studies demonstrated that intra-mPFC injection of the mGluR_2/3 receptor agonist, APDC, dose-dependently reduced acute behavioral response to cocaine (0.015-15 nmol/side with significant effects starting at 1.5nmol/side). The effects of APDC were prevented by intra-mPFC co-injections of an mGluR_2/3 antagonist, LY341495 (1.5 nmol/side). Repeated intra-mPFC APDC (1.5 nmol/side) injections also prevented the initiation of behavioral and neurochemical sensitization, which is defined as enhanced nucleus accumbens (NAc) dopamine response to cocaine. Once sensitization was …