Pharmacy and Pharmaceutical Sciences Commons^™

Targeted Magnetite Tissue Delivery For Antiretroviral Pharmacokinetics, Tianyuzi Li

Theses & Dissertations

Pharmacokinetics and pharmacodynamics studies are required for bench to bedside translation of any new drug, formulation or device. Multifunctional magnetite nanocarriers enable magnetic resonance imaging tracking of nanomaterial encased antiretroviral drugs serving to improve the effectiveness of formulation developments. Targeting ligands used to deliver nanoparticles to HIV harboring cells can be tested using multifunctional magnetite nanocarriers. To this end, two types of magnetite nanocarriers were developed. These included small magnetite antiretroviral therapy particles. The second were ALN-PEG coated magnetite particles for testing macrophages targeting ligands. Overall, these works should serve to speed the development of long acting nanoformulated ART to …

Polymeric Nanocarriers For Treatment Of Melanoma And Genetically Modified Mesenchymal Stem Cells To Improve Outcome Of Islet Transplantation, Vaibhav Mundra

Theses & Dissertations

Melanoma is a lethal malignancy with limited treatment options for advanced metastatic stages. New targeted therapeutic options with discovery of BRAF and MEK inhibitors have shown significant survival benefit. Despite the recent progress, inefficient tumor accumulation and dose limiting systemic toxicity remains pressing challenges for treating metastatic melanoma and there is a need for drug delivery approach to improve therapeutic index of chemotherapeutics. Nanoparticle based drug delivery represents promising approach to enhance efficacy and reduce the dose limiting systemic toxicity. Nanoparticles can be formulated either by physical encapsulation of drugs or by covalent conjugation of drugs to the polymeric backbone. …

Development Of Hypoxia Trapping Enhanced Bb2r-Targeted Radiopharmaceutics For Prostate Cancer, Zhengyuan Zhou

Theses & Dissertations

The Gastrin-Releasing Peptide Receptor (BB2r) has been investigated as a diagnostic and therapeutic target for prostate and other cancers due to the high expression level on neoplastic relative to normal tissues. A variety of BB2r-targeted agents have been developed utilizing the bombesin(BBN) peptide, which has shown nanomolar binding affinity to human BB2r. However, as with most of the low-molecular weight, receptor-targeted drugs, a major challenge to clinical translation of BB2r-targeted agents is the low retention at the tumor site due to intrinsically high diffusion and efflux rates. Our laboratory seeks to address this deficiency by developing synthetic approaches to selectively …

Role Of Macrophages In Muscle Transfection With Pdna/Pluronic Formulation, Vivek Mahajan

Theses & Dissertations

Non-ionic amphiphilic block copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO), Pluronics, arranged in a tri-block structure PEO-PPO-PEO, have raised a considerable interest in skeletal muscle Gene Therapy. Previous studies have demonstrated that co-administration of Pluronics with naked plasmid DNA (pDNA) by direct i.m. injection enhanced transgene expression not only in muscle but also in distal lymphoid organs (spleen and lymph nodes) and this response was strain-dependent; not observed in athymic (BALB/c nu/nu) mouse; suggesting a role of immune cells in gene transfer to skeletal muscles. Therefore, we first evaluated the role of inflammation and inflammatory cells, on muscle …

Samhd1 Is A Single-Stranded Nucleic Acid Binding Protein With No Active Site-Associated Nuclease Activity., Kyle J. Seamon, Zhiqiang Sun, Luda S. Shlyakhtenko, Yuri L. Lyubchenko, James T. Stivers

Journal Articles: Pharmaceutical Sciences

The HIV-1 restriction factor SAMHD1 is a tetrameric enzyme activated by guanine nucleotides with dNTP triphosphate hydrolase activity (dNTPase). In addition to this established activity, there have been a series of conflicting reports as to whether the enzyme also possesses single-stranded DNA and/or RNA 3'-5' exonuclease activity. SAMHD1 was purified using three chromatography steps, over which the DNase activity was largely separated from the dNTPase activity, but the RNase activity persisted. Surprisingly, we found that catalytic and nucleotide activator site mutants of SAMHD1 with no dNTPase activity retained the exonuclease activities. Thus, the exonuclease activity cannot be associated with any …

Remodeling Of Recg Helicase At The Dna Replication Fork By Ssb Protein., Zhiqiang Sun, Hui Yin Tan, Piero R. Bianco, Yuri L. Lyubchenko

Journal Articles: Pharmaceutical Sciences

The RecG DNA helicase a key player in stalled replication fork rescue. The single-stranded DNA binding protein (SSB) participates in this process, but its role in the interaction of RecG with the fork remains unclear. We used atomic force microscopy (AFM) to visualize the interaction of RecG with a fork DNA in the presence of SSB. We discovered that SSB enhances RecG loading efficiency onto the DNA fork by threefold. Additionally, SSB interacts with RecG leading to the RecG remodeling. As a result, RecG separates from the fork, but remains bound to the DNA duplex. Moreover, in this new binding …

Impact Of A High-Fat Meal On Assessment Of Clopidogrel-Induced Platelet Inhibition In Healthy Subjects., Paul P. Dobesh, Jamela F. Urban, Scott W. Shurmur, Julie H. Oestreich

Journal Articles: Pharmacy Practice

BACKGROUND: Ideal conditions for platelet reactivity testing are critical for optimal selection of a P2Y12 inhibitor. Data are inconsistent regarding the impact of high-fat meals on test assessment.

METHODS: Participants included 12 healthy subjects not taking antiplatelet drugs after a 12-hour fast. After baseline assessment, subjects were given a 600 mg dose of clopidogrel. Four hours later, maximum platelet inhibition was tested in the fasting state by light transmission aggregometry (LTA), VerifyNow P2Y12, vasodilator-stimulated phosphoprotein (VASP), and whole blood aggregometry (WBA). Subjects were then provided a high-fat meal, and platelet function was evaluated two hours later. Change in measured platelet …

Bridged Filaments Of Histone-Like Nucleoid Structuring Protein Pause Rna Polymerase And Aid Termination In Bacteria., Matthew V. Kotlajich, Daniel R. Hron, Beth A. Boudreau, Zhiqiang Sun, Yuri L. Lyubchenko, Robert Landick

Journal Articles: Pharmaceutical Sciences

Bacterial H-NS forms nucleoprotein filaments that spread on DNA and bridge distant DNA sites. H-NS filaments co-localize with sites of Rho-dependent termination in Escherichia coli, but their direct effects on transcriptional pausing and termination are untested. In this study, we report that bridged H-NS filaments strongly increase pausing by E. coli RNA polymerase at a subset of pause sites with high potential for backtracking. Bridged but not linear H-NS filaments promoted Rho-dependent termination by increasing pause dwell times and the kinetic window for Rho action. By observing single H-NS filaments and elongating RNA polymerase molecules using atomic force microscopy, we …

Hemagglutinin-Based Polyanhydride Nanovaccines Against H5n1 Influenza Elicit Protective Virus Neutralizing Titers And Cell-Mediated Immunity., Kathleen A. Ross, Hyelee Loyd, Wuwei Wu, Lucas Huntimer, Shaheen Ahmed, Anthony R. Sambol, Scott Broderick, Zachary Flickinger, Krishna Rajan, Tatiana K. Bronich, Surya Mallapragada, Michael J. Wannemuehler, Susan Carpenter, Balaji Narasimhan

Journal Articles: Pharmaceutical Sciences

H5N1 avian influenza is a significant global concern with the potential to become the next pandemic threat. Recombinant subunit vaccines are an attractive alternative for pandemic vaccines compared to traditional vaccine technologies. In particular, polyanhydride nanoparticles encapsulating subunit proteins have been shown to enhance humoral and cell-mediated immunity and provide protection upon lethal challenge. In this work, a recombinant H5 hemagglutinin trimer (H5₃) was produced and encapsulated into polyanhydride nanoparticles. The studies performed indicated that the recombinant H5₃ antigen was a robust immunogen. Immunizing mice with H5₃ encapsulated into polyanhydride nanoparticles induced high neutralizing antibody titers and enhanced CD4(+) T …

New Oral Anticoagulants For The Treatment Of Venous Thromboembolism: Understanding Differences And Similarities., Paul P. Dobesh, John Fanikos

Journal Articles: Pharmacy Practice

Venous thromboembolism (VTE) is a major cause of morbidity, mortality, and healthcare expenditure. In the United States, approximately 0.1 % of the population experiences an initial VTE event each year. Anticoagulation therapy is the cornerstone of acute VTE treatment and for prevention of recurrent VTE events. Conventional anticoagulants, including heparin, low-molecular-weight heparins, fondaparinux, and vitamin K antagonists are widely used but have limitations. Newer oral anticoagulant agents, including direct thrombin inhibitors (e.g., dabigatran etexilate) and direct factor Xa inhibitors (e.g., rivaroxaban, apixaban, and edoxaban) have been developed to attempt to overcome some of the limitations of conventional anticoagulant therapy. These …

Ticagrelor: Pharmacokinetics, Pharmacodynamics, Clinical Efficacy, And Safety., Paul P. Dobesh, Julie H. Oestreich

Journal Articles: Pharmacy Practice

Dual antiplatelet therapy, composed of aspirin plus a P2Y12 -receptor antagonist, is the cornerstone of treatment for patients with acute coronary syndrome (ACS). A number of U.S. Food and Drug Administration-approved P2Y12 -receptor antagonists are available for treating patients with ACS, including the thienopyridine compounds clopidogrel and prasugrel. Ticagrelor, the first of a new class of antiplatelet agents, is a noncompetitive, direct-acting P2Y12 -receptor antagonist. Unlike the thienopyridine compounds, ticagrelor does not require metabolism for activity. Also, whereas clopidogrel and prasugrel are irreversible inhibitors of the P2Y12 receptor, ticagrelor binds reversibly to inhibit receptor signaling and subsequent platelet activation. In …

Clinical Use Of Rivaroxaban: Pharmacokinetic And Pharmacodynamic Rationale For Dosing Regimens In Different Indications., Toby Trujillo, Paul P. Dobesh

Journal Articles: Pharmacy Practice

Target-specific oral anticoagulants have become increasingly available as alternatives to traditional agents for the management of a number of thromboembolic disorders. To date, the direct Factor Xa inhibitor rivaroxaban is the most widely approved of the new agents. The dosing of rivaroxaban varies and adheres to specific schedules in each of the clinical settings in which it has been investigated. These regimens were devised based on the results of phase II dose-finding studies and/or pharmacokinetic modeling, and were demonstrated to be successful in randomized, phase III studies. In most cases, the pharmacodynamic profile of rivaroxaban permits once-daily dosing. A once-daily …

Interaction Of Apobec3a With Dna Assessed By Atomic Force Microscopy., Luda S. Shlyakhtenko, Alexander J. Lushnikov, Ming Li, Reuben S. Harris, Yuri L. Lyubchenko

Journal Articles: Pharmaceutical Sciences

The APOBEC3 family of DNA cytosine deaminases functions to block the spread of endogenous retroelements and retroviruses including HIV-1. Potency varies among family members depending on the type of parasitic substrate. APOBEC3A (A3A) is unique among the human enzymes in that it is expressed predominantly in myeloid lineage cell types, it is strongly induced by innate immune agonists such as type 1 interferon, and it has the capacity to accommodate both normal and 5-methyl cytosine nucleobases. Here we apply atomic force microscopy (AFM) to characterize the interaction between A3A and single- and double-stranded DNA using a hybrid DNA approach in …

Anticancer Properties Of Distinct Antimalarial Drug Classes, Rob Hooft Van Huijsduijnen, R. Kiplin Guy, Kelly Chibale, Richard K. Haynes, Ingmar Peitz, Gerhard Kelter, Margaret A. Phillips, Jonathan L. Vennerstrom, Yongyuth Yuthavong, Timothy N. C. Wells

Journal Articles: Pharmaceutical Sciences

We have tested five distinct classes of established and experimental antimalarial drugs for their anticancer potential, using a panel of 91 human cancer lines. Three classes of drugs: artemisinins, synthetic peroxides and DHFR (dihydrofolate reductase) inhibitors effected potent inhibition of proliferation with IC50s in the nM- low µM range, whereas a DHODH (dihydroorotate dehydrogenase) and a putative kinase inhibitor displayed no activity. Furthermore, significant synergies were identified with erlotinib, imatinib, cisplatin, dasatinib and vincristine. Cluster analysis of the antimalarials based on their differential inhibition of the various cancer lines clearly segregated the synthetic peroxides OZ277 and OZ439 from the artemisinin …

Mechanism Of Amyloid Β-Protein Dimerization Determined Using Single-Molecule Afm Force Spectroscopy., Zhengjian Lv, Robin Roychaudhuri, Margaret M. Condron, David B. Teplow, Yuri L. Lyubchenko

Journal Articles: Pharmaceutical Sciences

Aβ42 and Aβ40 are the two primary alloforms of human amyloid β-protein (Aβ). The two additional C-terminal residues of Aβ42 result in elevated neurotoxicity compared with Aβ40, but the molecular mechanism underlying this effect remains unclear. Here, we used single-molecule force microscopy to characterize interpeptide interactions for Aβ42 and Aβ40 and corresponding mutants. We discovered a dramatic difference in the interaction patterns of Aβ42 and Aβ40 monomers within dimers. Although the sequence difference between the two peptides is at the C-termini, the N-terminal segment plays a key role in the peptide interaction in the dimers. This is an unexpected finding …

Mechanism Of Amyloid Β-Protein Dimerization Determined Using Single-Molecule Afm Force Spectroscopy., Zhengjian Lv, Robin Roychaudhuri, Margaret M Condron, David B. Teplow, Yuri L. Lyubchenko

Journal Articles: Pharmaceutical Sciences

Aβ42 and Aβ40 are the two primary alloforms of human amyloid β-protein (Aβ). The two additional C-terminal residues of Aβ42 result in elevated neurotoxicity compared with Aβ40, but the molecular mechanism underlying this effect remains unclear. Here, we used single-molecule force microscopy to characterize interpeptide interactions for Aβ42 and Aβ40 and corresponding mutants. We discovered a dramatic difference in the interaction patterns of Aβ42 and Aβ40 monomers within dimers. Although the sequence difference between the two peptides is at the C-termini, the N-terminal segment plays a key role in the peptide interaction in the dimers. This is an unexpected finding …

A Dexamethasone Prodrug Reduces The Renal Macrophage Response And Provides Enhanced Resolution Of Established Murine Lupus Nephritis, Fang Yuan, Dana Tabor, Richard K. Nelson, Hongjiang Yuan, Yijia Zhang, Jenny Nuxoll, Kimberly K. Bynote, Subodh M. Lele, Dong Wang, Karen A. Gould

Journal Articles: Pharmaceutical Sciences

We evaluated the ability of a macromolecular prodrug of dexamethasone (P-Dex) to treat lupus nephritis in (NZB × NZW)F1 mice. We also explored the mechanism underlying the anti-inflammatory effects of this prodrug. P-Dex eliminated albuminuria in most (NZB × NZW)F1 mice. Furthermore, P-Dex reduced the incidence of severe nephritis and extended lifespan in these mice. P-Dex treatment also prevented the development of lupus-associated hypertension and vasculitis. Although P-Dex did not reduce serum levels of anti-dsDNA antibodies or glomerular immune complexes, P-Dex reduced macrophage recruitment to the kidney and attenuated tubulointerstitial injury. In contrast to what was observed with free dexamethasone, …

Crystal Structure Of 3wj Core Revealing Divalent Ion-Promoted Thermostability And Assembly Of The Phi29 Hexameric Motor Prna., Hui Zhang, James A. Endrizzi, Yi Shu, Farzin Haque, Claude Sauter, Luda S. Shlyakhtenko, Yuri L. Lyubchenko, Peixuan Guo, Young-In Chi

Journal Articles: Pharmaceutical Sciences

The bacteriophage phi29 DNA packaging motor, one of the strongest biological motors characterized to date, is geared by a packaging RNA (pRNA) ring. When assembled from three RNA fragments, its three-way junction (3WJ) motif is highly thermostable, is resistant to 8 M urea, and remains associated at extremely low concentrations in vitro and in vivo. To elucidate the structural basis for its unusual stability, we solved the crystal structure of this pRNA 3WJ motif at 3.05 Å. The structure revealed two divalent metal ions that coordinate 4 nt of the RNA fragments. Single-molecule fluorescence resonance energy transfer (smFRET) analysis confirmed …

Proliferation Of Genetically Modified Human Cells On Electrospun Nanofiber Scaffolds., Mandula Borjigin, Bryan Strouse, Rohina A. Niamat, Pawel Bialk, Chris Eskridge, Jingwei Xie, Eric B. Kmiec

Journal Articles: Pharmaceutical Sciences

Gene editing is a process by which single base mutations can be corrected, in the context of the chromosome, using single-stranded oligodeoxynucleotides (ssODNs). The survival and proliferation of the corrected cells bearing modified genes, however, are impeded by a phenomenon known as reduced proliferation phenotype (RPP); this is a barrier to practical implementation. To overcome the RPP problem, we utilized nanofiber scaffolds as templates on which modified cells were allowed to recover, grow, and expand after gene editing. Here, we present evidence that some HCT116-19, bearing an integrated, mutated enhanced green fluorescent protein (eGFP) gene and corrected by gene editing, …

Effect Of Spermidine On Misfolding And Interactions Of Alpha-Synuclein., Alexey V. Krasnoslobodtsev, Jie Peng, Josephat M. Asiago, Jagadish Hindupur, Jean-Christophe Rochet, Yuri L. Lyubchenko

Journal Articles: Pharmaceutical Sciences

Alpha-synuclein (α-Syn) is a 140 aa presynaptic protein which belongs to a group of natively unfolded proteins that are unstructured in aqueous solutions. The aggregation rate of α-Syn is accelerated in the presence of physiological levels of cellular polyamines. Here we applied single molecule AFM force spectroscopy to characterize the effect of spermidine on the very first stages of α-Syn aggregation--misfolding and assembly into dimers. Two α-Syn variants, the wild-type (WT) protein and A30P, were studied. The two protein molecules were covalently immobilized at the C-terminus, one at the AFM tip and the other on the substrate, and intermolecular interactions …

The Role Of Histone H4 Biotinylation In The Structure Of Nucleosomes., Nina A. Filenko, Carol Kolar, John T. West, S. Abbie Smith, Yousef I. Hassan, Gloria E.O. Borgstahl, Janos Zempleni, Yuri L. Lyubchenko

Journal Articles: Pharmaceutical Sciences

BACKGROUND: Post-translational modifications of histones play important roles in regulating nucleosome structure and gene transcription. It has been shown that biotinylation of histone H4 at lysine-12 in histone H4 (K12Bio-H4) is associated with repression of a number of genes. We hypothesized that biotinylation modifies the physical structure of nucleosomes, and that biotin-induced conformational changes contribute to gene silencing associated with histone biotinylation.

METHODOLOGY/PRINCIPAL FINDINGS: To test this hypothesis we used atomic force microscopy to directly analyze structures of nucleosomes formed with biotin-modified and non-modified H4. The analysis of the AFM images revealed a 13% increase in the length of DNA …

Dna Synapsis Through Transient Tetramerization Triggers Cleavage By Ecl18ki Restriction Enzyme., Mindaugas Zaremba, Amelia Owsicka, Gintautas Tamulaitis, Giedrius Sasnauskas, Luda S. Shlyakhtenko, Alexander Y. Lushnikov, Yuri L. Lyubchenko, Niels Laurens, Bram Van Den Broek, Gijs J.L. Wuite, Virginijus Siksnys

Journal Articles: Pharmaceutical Sciences

To cut DNA at their target sites, restriction enzymes assemble into different oligomeric structures. The Ecl18kI endonuclease in the crystal is arranged as a tetramer made of two dimers each bound to a DNA copy. However, free in solution Ecl18kI is a dimer. To find out whether the Ecl18kI dimer or tetramer represents the functionally important assembly, we generated mutants aimed at disrupting the putative dimer-dimer interface and analysed the functional properties of Ecl18kI and mutant variants. We show by atomic force microscopy that on two-site DNA, Ecl18kI loops out an intervening DNA fragment and forms a tetramer. Using the …

Site-Specific Labeling Of Supercoiled Dna., Alexander Y. Lushnikov, Vladimir N. Potaman, Yuri L. Lyubchenko

Journal Articles: Pharmaceutical Sciences

Visualization of site-specific labels in long linear or circular DNA allows unambiguous identification of various local DNA structures. Here we describe a novel and efficient approach to site-specific DNA labeling. The restriction enzyme SfiI binds to DNA but leaves it intact in the presence of calcium and therefore may serve as a protein label of 13 bp recognition sites. Since SfiI requires simultaneous interaction with two DNA recognition sites for stable binding, this requirement is satisfied by providing an isolated recognition site in the DNA target and an additional short DNA duplex also containing the recognition site. The SfiI/DNA complexes …

Triplet Repeat Dna Structures And Human Genetic Disease: Dynamic Mutations From Dynamic Dna., Richard R. Sinden, Vladimir N. Potaman, Elena A. Oussatcheva, Christopher E. Pearson, Yuri L. Lyubchenko, Luda S. Shlyakhtenko

Journal Articles: Pharmaceutical Sciences

Fourteen genetic neurodegenerative diseases and three fragile sites have been associated with the expansion of (CTG)n (CAG)n, (CGG)n (CCG)n, or (GAA)n (TTC)n repeat tracts. Different models have been proposed for the expansion of triplet repeats, most of which presume the formation of alternative DNA structures in repeat tracts. One of the most likely structures, slipped strand DNA, may stably and reproducibly form within triplet repeat sequences. The propensity to form slipped strand DNA is proportional to the length and homogeneity of the repeat tract. The remarkable stability of slipped strand DNA may, in part, be due to loop-loop interactions facilitated …