Physical Sciences and Mathematics Commons^™

Near Simultaneous Laser Scanning Confocal And Atomic Force Microscopy (Conpokal) On Live Cells, Joree N. Sandin, Surya P. Aryal, Thomas E. Wilkop, Christopher I. Richards, Martha E. Grady

Physiology Faculty Publications

Techniques available for micro- and nano-scale mechanical characterization have exploded in the last few decades. From further development of the scanning and transmission electron microscope, to the invention of atomic force microscopy, and advances in fluorescent imaging, there have been substantial gains in technologies that enable the study of small materials. Conpokal is a portmanteau that combines confocal microscopy with atomic force microscopy (AFM), where a probe "pokes" the surface. Although each technique is extremely effective for the qualitative and/or quantitative image collection on their own, Conpokal provides the capability to test with blended fluorescence imaging and mechanical characterization. Designed …

Absolute Configuration Of 2,2',3,3',6-Pentachlorinatedbiphenyl (Pcb 84) Atropisomers, Xueshu Li, Sean R. Parkin, Hans-Joachim Lehmler

Chemistry Faculty Publications

Nineteen polychlorinated biphenyl (PCB) congeners, such as 2,2′,3,3′,6-pentachlorobiphenyl (PCB 84), display axial chirality because they form stable rotational isomers, or atropisomers, that are non-superimposable mirror images of each other. Although chiral PCBs undergo atropselective biotransformation and atropselectively alter biological processes, the absolute structure of only a few PCB atropisomers has been determined experimentally. To help close this knowledge gap, pure PCB 84 atropisomers were obtained by semi-preparative liquid chromatography with two serially connected Nucleodex β-PM columns. The absolute configuration of both atropisomers was determined by X-ray single-crystal diffraction. The PCB 84 atropisomer eluting first and second on the Nucleodex β-PM …

Fluoroethoxy-1,4-Diphenethylpiperidine And Piperazine Derivatives: Potent And Selective Inhibitors Of [3H]Dopamine Uptake At The Vesicular Monoamine Transporter-2, Emily R. Hankosky, Shyam R. Joolakanti, Justin R. Nickell, Venumadhav Janganati, Linda P. Dwoskin, Peter A. Crooks

Pharmaceutical Sciences Faculty Publications

A small library of fluoroethoxy-1,4-diphenethyl piperidine and fluoroethoxy-1,4-diphenethyl piperazine derivatives were designed, synthesized and evaluated for their ability to inhibit [³H]dopamine (DA) uptake at the vesicular monoamine transporter-2 (VMAT2) and dopamine transporter (DAT), [³H]serotonin (5-HT) uptake at the serotonin transporter (SERT), and [³H]dofetilide binding at the human-ether-a-go-go-related gene (hERG) channel. The majority of the compounds exhibited potent inhibition of [³H]DA uptake at VMAT2, with Ki values in the nanomolar range (K_i = 0.014–0.073 μM). Compound 15d exhibited the highest affinity (K_i = 0.014 μM) at VMAT2, and had 160-, 5-, …

Design, Synthesis, And Biological Activity Of 5'-Phenyl-1,2,5,6-Tetrahydro-3,3'-Bipyridine Analogues As Potential Antagonists Of Nicotinic Acetylcholine Receptors, Yafei Jin, Xiaoqin Huang, Roger L. Papke, Emily M. Jutkiewicz, Hollis D Showalter, Chang-Guo Zhan

Pharmaceutical Sciences Faculty Publications

Starting from a known non-specific agonist (1) of nicotinic acetylcholine receptors (nAChRs), rationally guided structural-based design resulted in the discovery of a small series of 5′-phenyl-1,2,5,6-tetrahydro-3,3′-bipyridines (3a – 3e) incorporating a phenyl ring off the pyridine core of 1. The compounds were synthesized via successive Suzuki couplings on a suitably functionalized pyridine starting monomer 4 to append phenyl and pyridyl substituents off the 3- and 5-positions, respectively, and then make subsequent modifications on the flanking pyridyl ring to provide target compounds. Compound 3a is a novel antagonist which is highly selective for α3β4 nAChR (K_i = 123 nM) …

Selective Inhibitors Of Human Mpges-1 From Structure-Based Computational Screening, Ziyuan Zhou, Yaxia Yuan, Shuo Zhou, Kai Ding, Fang Zheng, Chang-Guo Zhan

Molecular Modeling and Biopharmaceutical Center Faculty Publications

Human mPGES-1 is recognized as a promising target for next generation of anti-inflammatory drugs. Although various mPGES-1 inhibitors have been reported in literature, few have entered clinical trials and none has been proven clinically useful so far. It is highly desired for developing the next generation of therapeutics for inflammation-related diseases to design and discover novel inhibitors of mPGES-1 with new scaffolds. Here, we report the identification of a series of new, potent and selective inhibitors of human mPGES-1 with diverse scaffolds through combined computational and experimental studies. The computationally modeled binding structures of these new inhibitors with mPGES-1 provide …

Mccrearamycins A-D, Geldanamycin-Derived Cyclopentenone Macrolactams From An Eastern Kentucky Abandoned Coal Mine Microbe, Xiachang Wang, Yinan Zhang, Larissa V. Ponomareva, Qingchao Qiu, Ryan M. Woodcock, Sherif I. Elshahawi, Xiabin Chen, Ziyuan Zhou, Bruce E. Hatcher, James C. Hower, Chang-Guo Zhan, Sean Parkin, Madan K. Kharel, S. Randal Voss, Khaled A. Shaaban, Jon S. Thorson

Center for Pharmaceutical Research and Innovation Faculty Publications

Four cyclopentenone‐containing ansamycin polyketides (mccrearamycins A–D), and six new geldanamycins (Gdms B–G, including new linear and mycothiol conjugates), were characterized as metabolites of Streptomyces sp. AD‐23‐14 isolated from the Rock Creek underground coal mine acid drainage site. Biomimetic chemical conversion studies using both simple synthetic models and Gdm D confirmed that the mccrearamycin cyclopentenone derives from benzilic acid rearrangement of 19‐hydroxy Gdm, and thereby provides a new synthetic derivatization strategy and implicates a potential unique biocatalyst in mccrearamycin cyclopentenone formation. In addition to standard Hsp90α binding and cell line cytotoxicity assays, this study also highlights the first assessment of Hsp90α …

Bis(N-Amidinohydrazones) And N-(Amidino)-N'-Aryl-Bishydrazones: New Classes Of Antibacterial/Antifungal Agents, Sanjib K. Shrestha, Liliia M. Kril, Keith D. Green, Stefan Kwiatkowski, Vitaliy M. Sviripa, Justin Robert Nickell, Linda Phyliss Dwoskin, David S. Watt, Sylvie Garneau-Tsodikova

Pharmaceutical Sciences Faculty Publications

The emergence of multidrug-resistant bacterial and fungal strains poses a threat to human health that requires the design and synthesis of new classes of antimicr obial agents. We evaluated bis(N-amidinohydrazones) and N-(amidino)-N'-aryl-bishydrazones for their antibacterial and antifungal activities against panels of Gram-positive/Gram-negative bacteria as well as fungi. We investigated their potential to develop resistance against both bacteria and fungi by a multi-step, resistance-selection method, explored their potential to induce the production of reactive oxygen species, and assessed their toxicity. In summary, we found that these compounds exhibited broad-spectrum antibacterial and antifungal activities against most of …

Mutation Linked To Autosomal Dominant Nocturnal Frontal Lobe Epilepsy Reduces Low-Sensitivity Α4Β2, And Increases Α5Α4Β2, Nicotinic Receptor Surface Expression, Weston A. Nichols, Brandon J. Henderson, Christopher B. Marotta, Caroline Y. Yu, Chris Richards, Dennis A. Dougherty, Henry A. Lester, Bruce N. Cohen

Chemistry Faculty Publications

A number of mutations in α4β2-containing (α4β2*) nicotinic acetylcholine (ACh) receptors (nAChRs) are linked to autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), including one in the β2 subunit called β2V287L. Two α4β2* subtypes with different subunit stoichiometries and ACh sensitivities co-exist in the brain, a high-sensitivity subtype with (α4)₂(β2)₃ subunit stoichiometry and a low-sensitivity subtype with (α4)₃(β2)₂ stoichiometry. The α5 nicotinic subunit also co-assembles with α4β2 to form a high-sensitivity α5α4β2 nAChR. Previous studies suggest that the β2V287L mutation suppresses low-sensitivity α4β2* nAChR expression in a knock-in mouse model and also that α5 co-expression …

It Is All About (U)Biquitin: Role Of Altered Ubiquitin-Proteasome System And Uchl1 In Alzheimer Disease, Antonella Tramutola, Fabio Di Domenico, Eugenio Barone, Marzia Perluigi, D. Allan Butterfield

Chemistry Faculty Publications

Free radical-mediated damage to macromolecules and the resulting oxidative modification of different cellular components are a common feature of aging, and this process becomes much more pronounced in age-associated pathologies, including Alzheimer disease (AD). In particular, proteins are particularly sensitive to oxidative stress-induced damage and these irreversible modifications lead to the alteration of protein structure and function. In order to maintain cell homeostasis, these oxidized/damaged proteins have to be removed in order to prevent their toxic accumulation. It is generally accepted that the age-related accumulation of “aberrant” proteins results from both the increased occurrence of damage and the decreased efficiency …

The Nicotine Metabolite, Cotinine, Alters The Assembly And Trafficking Of A Subset Of Nicotinic Acetylcholine Receptors, Ashley M. Fox, Faruk H. Moonschi, Christopher I. Richards

Chemistry Faculty Publications

Exposure to nicotine alters the trafficking and assembly of nicotinic receptors (nAChRs), leading to their up-regulation on the plasma membrane. Although the mechanism is not fully understood, nicotine-induced up-regulation is believed to contribute to nicotine addiction. The effect of cotinine, the primary metabolite of nicotine, on nAChR trafficking and assembly has not been extensively investigated. We utilize a pH-sensitive variant of GFP, super ecliptic pHluorin, to differentiate between intracellular nAChRs and those expressed on the plasma membrane to quantify changes resulting from cotinine and nicotine exposure. Similar to nicotine, exposure to cotinine increases the number of α4β2 receptors on the …

Comparison Of Crystal Structures Of 4-(Benzo[B]Thiophen-2-Yl)-5-(3,4,5-Trimethoxyphenyl)-2H-1,2,3-Triazole And 4-(Benzo[B]Thiophen-2-Yl)-2-Methyl-5-(3,4,5-Trimethoxyphenyl)-2H-1,2,3-Triazole, Narsimha Reddy Penthala, Nikhil Reddy Madadi, Shobanbabu Bommagani, Sean Parkin, Peter A. Crooks

Chemistry Faculty Publications

The title compound, C₁₉H₁₇N₃O₃S (I), was prepared by a [3 + 2]cyclo­addition azide condensation reaction using sodium azide and l-proline as a Lewis base catalyst. N-Methyl­ation of compound (I) using CH₃I gave compound (II), C₂₀H₁₉N₃O₃S. The benzo­thio­phene ring systems in (I) and (II) are almost planar, with r.m.s deviations from the mean plane = 0.0205 (14) in (I) and 0.016 (2) Å in (II). In (I) and (II), the triazole rings make dihedral angles of 32.68 (5) and 10.43 (8)°, respectively, …

Thimerosal Exposure And The Role Of Sulfation Chemistry And Thiol Availability In Autism, Janet K. Kern, Boyd E. Haley, David A. Geier, Lisa K. Sykes, Paul G. King, Mark R. Geier

Chemistry Faculty Publications

Autism spectrum disorder (ASD) is a neurological disorder in which a significant number of the children experience a developmental regression characterized by a loss of previously acquired skills and abilities. Typically reported are losses of verbal, nonverbal, and social abilities. Several recent studies suggest that children diagnosed with an ASD have abnormal sulfation chemistry, limited thiol availability, and decreased glutathione (GSH) reserve capacity, resulting in a compromised oxidation/reduction (redox) and detoxification capacity. Research indicates that the availability of thiols, particularly GSH, can influence the effects of thimerosal (TM) and other mercury (Hg) compounds. TM is an organomercurial compound (49.55% Hg …

Amyloid Β-Peptide (1–42)-Induced Oxidative Stress In Alzheimer Disease: Importance In Disease Pathogenesis And Progression, D. Allan Butterfield, Aaron M. Swomley, Rukhsana Sultana

Chemistry Faculty Publications

Significance: Alzheimer disease (AD) is an age-related neurodegenerative disease. AD is characterized by progressive cognitive impairment. One of the main histopathological hallmarks of AD brain is the presence of senile plaques (SPs) and another is elevated oxidative stress. The main component of SPs is amyloid beta-peptide (Aβ) that is derived from the proteolytic cleavage of amyloid precursor protein.

Recent Advances: Recent studies are consistent with the notion that methionine present at 35 position of Aβ is critical to Aβ-induced oxidative stress and neurotoxicity. Further, we also discuss the signatures of oxidatively modified brain proteins, identified using redox proteomics approaches, during …

Lipopolysaccharide Impairs Amyloid Β Efflux From Brain: Altered Vascular Sequestration, Cerebrospinal Fluid Reabsorption, Peripheral Clearance And Transporter Function At The Blood-Brain Barrier, Michelle A. Erickson, Pehr E. Hartvigson, Yoichi Morofuji, Joshua B. Owen, D. Allan Butterfield, William A. Banks

Chemistry Faculty Publications

BACKGROUND: Defects in the low density lipoprotein receptor-related protein-1 (LRP-1) and p-glycoprotein (Pgp) clearance of amyloid beta (Aβ) from brain are thought to contribute to Alzheimer's disease (AD). We have recently shown that induction of systemic inflammation by lipopolysaccharide (LPS) results in impaired efflux of Aβ from the brain. The same treatment also impairs Pgp function. Here, our aim is to determine which physiological routes of Aβ clearance are affected following systemic inflammation, including those relying on LRP-1 and Pgp function at the blood-brain barrier.

METHODS: CD-1 mice aged between 6 and 8 weeks were treated with 3 intraperitoneal injections …

Oxidative Stress In Hpv-Driven Viral Carcinogenesis: Redox Proteomics Analysis Of Hpv-16 Dysplastic And Neoplastic Tissues, Federico De Marco, Elona Bucaj, Cesira Foppoli, Ada Fiorini, Carla Blarzino, Kozeta Filipi, Alessandra Giorgi, Maria Eugenia Schininà, Fabio Di Domenico, Raffaella Coccia, D. Allan Butterfield, Marzia Perluigi

Chemistry Faculty Publications

Genital infection by high risk Human Papillomavirus (HR-HPV), although recognized as the main etio-pathogenetic factor of cervical cancer, is not per se sufficient to induce tumour development. Oxidative stress (OS) represents an interesting and under-explored candidate as a promoting factor in HPV-initiated carcinogenesis. To gain insight into the role of OS in cervical cancer, HPV-16 positive tissues were collected from patients with invasive squamous cervical carcinoma, from patients with High Grade dysplastic HPV lesions and from patients with no clinical evidence of HPV lesions. After virological characterization, modulation of proteins involved in the redox status regulation was investigated. ERp57 and …

Rna Oxidation Adducts 8-Ohg And 8-Oha Change With Aβ42 Levels In Late-Stage Alzheimer's Disease, Adam M. Weidner, Melissa A. Bradley, Tina L. Beckett, Dana M. Niedowicz, Amy L.S. Dowling, Sergey V. Matveev, Harry Levine, Mark A. Lovell, M. Paul Murphy

Sanders-Brown Center on Aging Faculty Publications

While research supports amyloid-β (Aβ) as the etiologic agent of Alzheimer's disease (AD), the mechanism of action remains unclear. Evidence indicates that adducts of RNA caused by oxidation also represent an early phenomenon in AD. It is currently unknown what type of influence these two observations have on each other, if any. We quantified five RNA adducts by gas chromatography/mass spectroscopy across five brain regions from AD cases and age-matched controls. We then used a reductive directed analysis to compare the RNA adducts to common indices of AD neuropathology and various pools of Aβ. Using data from four disease-affected brain …

White Matter Diffusion Alterations In Normal Women At Risk Of Alzheimer's Disease, Charles D. Smith, Himachandra Chebrolu, Anders H. Andersen, David A. Powell, Mark A. Lovell, Shuling Xiong, Brian T. Gold

Neurology Faculty Publications

Increased white matter mean diffusivity and decreased fractional anisotropy (FA) has been observed in subjects diagnosed with mild cognitive impairment (MCI) and Alzheimer's disease (AD). We sought to determine whether similar alterations of white matter occur in normal individuals at risk of AD. Diffusion tensor images were acquired in 42 cognitively normal right-handed women with both a family history of dementia and at least one apolipoprotein E4 allele. These were compared with images from 23 normal women without either AD risk factor. Group analyses were performed using tract-based spatial statistics. Reduced FA was observed in the fronto-occipital and inferior temporal …

Oxidative Dna Damage In Mild Cognitive Impairment And Late-Stage Alzheimer's Disease, Mark A. Lovell, William R. Markesbery

Chemistry Faculty Publications

Increasing evidence supports a role for oxidative DNA damage in aging and several neurodegenerative diseases including Alzheimer's disease (AD). Attack of DNA by reactive oxygen species (ROS), particularly hydroxyl radicals, can lead to strand breaks, DNA–DNA and DNA–protein cross-linking, and formation of at least 20 modified bases adducts. In addition, α,β-unsaturated aldehydic by-products of lipid peroxidation including 4-hydroxynonenal and acrolein can interact with DNA bases leading to the formation of bulky exocyclic adducts. Modification of DNA bases by direct interaction with ROS or aldehydes can lead to mutations and altered protein synthesis. Several studies of DNA base adducts in late-stage …