Medical Biochemistry Commons^™

Hiv-1-Tat Protein Inhibits Sc35-Mediated Tau Exon 10 Inclusion Through Up-Regulation Of Dyrk1a Kinase, Ferdous Kadri, Marco Pacifici, Anna Wilk, Amanda Parker-Struckhoff, Luis Del Valle, Kurt F. Hauser, Pamela E. Knapp, Christopher Parsons, Duane Jeansonne, Adam Lassak, Francesca Peruzzi

School of Medicine Faculty Publications

The HIV-1 transactivator protein Tat is implicated in the neuronal damage that contributes to neurocognitive impairment affecting people living with HIV/AIDS. Aberrant splicing of TAU exon 10 results in tauopathies characterized by alterations in the proportion of TAU isoforms containing three (3R) or four (4R) microtubule-binding repeats. The splicing factor SC35/SRSF2 binds to nuclear RNA and facilitates the incorporation of exon 10 in the TAU molecule. Here, we utilized clinical samples, an animal model, and neuronal cell cultures and found that Tat promotes TAU 3R up-regulation through increased levels of phosphorylated SC35, which is retained in nuclear speckles. This mechanism …

Steroid Receptor Isoform Expression In Drosophila Nociceptor Neurons Is Required For Normal Dendritic Arbor And Sensitivity, Aidan L. Mcparland, Taylor L. Follansbee, Gwendolyn D. Vesenka, Alexandra E. Panaitiu, Geoffrey K. Ganter

Biology Student Publications

Steroid hormones organize many aspects of development, including that of the nervous system. Steroids also play neuromodulatory and other activational roles, including regulation of sensitivity to painful stimuli in mammals. In Drosophila, ecdysteroids are the only steroid hormones, and therefore the fly represents a simplified model system in which to explore mechanisms of steroid neuromodulation of nociception. In this report, we present evidence that ecdysteroids, acting through two isoforms of their nuclear ecdysone receptor (EcR), modulate sensitivity to noxious thermal and mechanical stimuli in the fly larva. We show that EcRA and EcRB1 are expressed by third instar larvae in …

Diabetic Ketoacidosis: Pathophysiology And Treatment, Laura E. Mumme

The Kabod

The pathophysiology of DKA in patients with T1D is addressed, followed by a discussion of proper emergency treatment for this life-threatening condition.

Pnaktide Inhibits Na/K-Atpase Reactive Oxygen Species Amplification And Attenuates Adipogenesis, Komal Sodhi, Kyle Maxwell, Yanling Yan, Jiang Liu, Muhammad Chaudhry, Morgan Getty, Zijian Xie, Nader G. Abraham, Joseph I. Shapiro Md

Biochemistry and Microbiology

Obesity has become a worldwide epidemic and is a major risk factor for metabolic syndrome. Oxidative stress is known to play a role in the generation and maintenance of an obesity phenotype in both isolated adipocytes and intact animals. Because we had identified that the Na/K-ATPase can amplify oxidant signaling, we speculated that a peptide designed to inhibit this pathway, pNaKtide, might ameliorate an obesity phenotype. To test this hypothesis, we first performed studies in isolated murine preadipocytes (3T3L1 cells) and found that pNaKtide attenuated oxidant stress and lipid accumulation in a dose-dependent manner. Complementary experiments in C57Bl6 mice fed …

Autophosphorylation Of The Smk1 Mapk Is Spatially And Temporally Regulated By Ssp2 During Meiotic Development In Yeast., Chong Wai Tio, Gregory Omerza, Sham Sunder, Edward Winter

Department of Biochemistry and Molecular Biology Faculty Papers

Smk1 is a meiosis-specific MAPK that controls spore wall morphogenesis in Saccharomyces cerevisiae. Although Smk1 is activated by phosphorylation of the threonine (T) and tyrosine (Y) in its activation loop, it is not phosphorylated by a dual-specificity MAPK kinase. Instead, the T is phosphorylated by the cyclin-dependent kinase (CDK)-activating kinase, Cak1. The Y is autophosphorylated in an intramolecular reaction that requires a meiosis-specific protein named Ssp2. The meiosis-specific CDK-like kinase, Ime2, was previously shown to positively regulate Smk1. Here we show that Ime2 activity is required to induce the translation of SSP2 mRNA at anaphase II. Ssp2 protein is then …

Distributed Task Related Bold Signal During Auditory Sub-Second Timing, Yuriy Bronshteyn

Kaleidoscope

The brain's input/output functions depend heavily on temporal processing. We sought to identify regions of the brain active in task performance during temporal discrimination of a sub-second auditory interval. We presented ten subjects with 40 paired tones and asked them to judge whether these comparison intervals were longer or shorter than a 100 ms standard. We then localized correlations between the Blood Oxygenation Level Dependent signal and task performance across subjects using event-related functional magnetic resonance imaging. We saw no task-related frontal cortex activation and significant activation of traditional auditory areas. Auditory regions included the bilateral superior and middle temporal …

The Controversy Of Vaccinations, Nicholas G. Aboreden

The Kabod

Recently vaccination has become a controversial topic. There is a growing number of people who believe that vaccines carry great health risks to patients and therefore refuse to be vaccinated or to vaccinate their children. This ill-informed view of immunizations is beginning to cause serious problems in the United States as growing numbers of disease cases are being seen. A closer look into the science of vaccines and the benefits they have brought, clearly show that not only do vaccines carry very little risk to patients, but they are responsible for the eradication and reduction of multiple debilitating diseases.

Eisosomes Provide Membrane Reservoirs For Rapid Expansion Of The Yeast Plasma Membrane, Ruth Kabeche, Louisa Howard, James B. Moseley

Dartmouth Scholarship

Cell surface area rapidly increases during mechanical and hypoosmotic stresses. Such expansion of the plasma membrane requires 'membrane reservoirs' that provide surface area and buffer membrane tension, but the sources of this membrane remain poorly understood. In principle, the flattening of invaginations and buds within the plasma membrane could provide this additional surface area, as recently shown for caveolae in animal cells. Here, we used microfluidics to study the rapid expansion of the yeast plasma membrane in protoplasts, which lack the rigid cell wall. To survive hypoosmotic stress, yeast cell protoplasts required eisosomes, protein-based structures that generate long invaginations at …

Role Of Cytoskeletal Dynamics In Platelet Arf6 Activation, Brett Taylor Begley

Kaleidoscope

Platelets undergo morphological changes upon activation, such as shape change and aggregation. These changes are known to be the result of actin remodeling, whereas the role of microtubule remodeling has been controversial. The objective of this study was to re-examine the role of actin and microtubule dynamics in platelet function. We used aggregometry to measure the effect of cytoskeletal inhibitors on platelet shape change, aggregation, and dense core release. Microtubule assembly was found to have no role in platelet function, because treatment with vinblastine or nocodazole had no effect on shape change, aggregation, or secretion. Microtubule disassembly was necessary for …

Palmitic Acid Activation Of Dendritic Cells: Implications For Type 2 Diabetes, Dequina Angelina Nicholas

Loma Linda University Electronic Theses, Dissertations & Projects

Infiltration of immune cells into visceral adipose tissue is observed in type 2 diabetes development. Monocytes are recruited to obese visceral adipose tissue in large numbers and retain the ability to differentiate into dendritic cells, important antigen presenting cells in the immune system. Differentiation of monocytes into dendritic cells likely accounts for the increased number of dendritic cells observed in the adipose tissue of type 2 diabetic patients. We have demonstrated this differentiation process is regulated in part by a major reduction of linker histone proteins. In adipose tissue, dendritic cells are exposed to high levels of saturated fatty acids. …

Platelet-Activating Factor Receptor Affects Food Intake And Body Weight, Wei Li, Thomas M. Mcintyre

Biomedical Sciences

“Let’s Move!” is a comprehensive initiative, launched by the First Lady, Michelle Obama, dedicates to solving problems of obesity, which is growing in child. The life behaviors do affect obesity; however, the mechanistic insight in molecular level is still not clear. In this study, by continually monitoring mouse body weight under chow and high fat western diets as well as metabolic, physical activity and food intake behaviors assessed in a CLAMS Comprehensive Lab Animal Monitoring System, we demonstrated that the platelet-activating factor receptor (PTAFR) contributes to modification of life behaviors. PTAFR does not affect metabolism of ingested dietary fat and …

Atomic Structure Of Grk5 Reveals Distinct Structural Features Novel For G Protein-Coupled Receptor Kinases, Konstantin E. Komolov, Anshul Bhardwaj, Jeffrey L. Benovic

Department of Biochemistry and Molecular Biology Faculty Papers

G protein-coupled receptor kinases (GRKs) are members of the protein kinase A, G, and C families (AGC) and play a central role in mediating G protein-coupled receptor phosphorylation and desensitization. One member of the family, GRK5, has been implicated in several human pathologies, including heart failure, hypertension, cancer, diabetes, and Alzheimer disease. To gain mechanistic insight into GRK5 function, we determined a crystal structure of full-length human GRK5 at 1.8 Å resolution. GRK5 in complex with the ATP analog 5'-adenylyl β,γ-imidodiphosphate or the nucleoside sangivamycin crystallized as a monomer. The C-terminal tail (C-tail) of AGC kinase domains is a highly …

Electrochemical Characterization Of Protein Adsorption Onto Yngrt-Au And Vlgxe-Au Surfaces, Hanna Trzeciakiewicz, Jose Esteves-Villanueva, Rania Soudy, Kamaljit Kaur, Sanela Martic-Milne

Pharmacy Faculty Articles and Research

The adsorption of the proteins CD13, mucin and bovine serum albumin on VLGXE-Au and YNGRT-Au interfaces was monitored by electrochemical impedance spectroscopy in the presence of [Fe(CN)6]3−/4−. The hydrophobicity of the Au surface was tailored using specific peptides, blocking agents and diluents. The combination of blocking agents (ethanolamine or n-butylamine) and diluents (hexanethiol or 2-mercaptoethanol) was used to prepare various peptide-modified Au surfaces. Protein adsorption onto the peptide-Au surfaces modified with the combination of n-butylamine and hexanethiol produced a dramatic decrease in the charge transfer resistance, Rct, for all three proteins. In contrast, polar peptide-surfaces induced a minimal change in …

Synthesis And Flammability Testing Of Epoxy Functionalized Phosphorous-Based Flame Retardants, Vladimir Benin, Xuemei Cui, Alexander Morgan, Karl Seiwert

Chemistry Faculty Publications

Several potential new phosphorus-containing flame retardant molecules were evaluated for heat release reduction potential by incorporation of the molecules into a polyurethane, generated from methylene diphenyl diisocyanate and 1,3-propane diol. The heat release reduction potential of these substances was evaluated using the pyrolysis combustion flow calorimeter (PCFC). The polyurethanes were prepared in the presence of the potential flame retardants via solvent mixing and copolymerization methods to qualitatively evaluate their potential reactivity into the polyurethane prior to heat release testing. The functionality of the flame retardants was epoxide based that would potentially react with the diol during polyurethane synthesis. Flammability testing …

The Rise And Fall Of Poly(Adp-Ribose): An Enzymatic Perspective., John M. Pascal, Tom Ellenberger

Department of Biochemistry and Molecular Biology Faculty Papers

Human cells respond to DNA damage with an acute and transient burst in production of poly(ADP-ribose), a posttranslational modification that expedites damage repair and plays a pivotal role in cell fate decisions. Poly(ADP-ribose) polymerases (PARPs) and glycohydrolase (PARG) are the key set of enzymes that orchestrate the rise and fall in cellular levels of poly(ADP-ribose). In this perspective, we focus on recent structural and mechanistic insights into the enzymes involved in poly(ADP-ribose) production and turnover, and we highlight important questions that remain to be answered.

Sex Hormone-Dependent Trna Halves Enhance Cell Proliferation In Breast And Prostate Cancers., Shozo Honda, Phillipe Loher, Megumi Shigematsu, Juan P. Palazzo, Ryusuke Suzuki, Issei Imoto, Isidore Rigoutsos, Yohei Kirino, Phd

Computational Medicine Center Faculty Papers

Sex hormones and their receptors play critical roles in the development and progression of the breast and prostate cancers. Here we report that a novel type of transfer RNA (tRNA)-derived small RNA, termed Sex HOrmone-dependent TRNA-derived RNAs (SHOT-RNAs), are specifically and abundantly expressed in estrogen receptor (ER)-positive breast cancer and androgen receptor (AR)-positive prostate cancer cell lines. SHOT-RNAs are not abundantly present in ER(-) breast cancer, AR(-) prostate cancer, or other examined cancer cell lines from other tissues. ER-dependent accumulation of SHOT-RNAs is not limited to a cell culture system, but it also occurs in luminal-type breast cancer patient tissues. …

Cellular Prostatic Acid Phosphatase (Cpacp) Serves As A Useful Biomarker Of Histone Deacetylase (Hdac) Inhibitors In Prostate Cancer Cell Growth Suppression., Yu-Wei Chou, Fen-Fen Lin, Sakthivel Muniyan, Frank C. Lin, Ching-Shih Chen, Jue Wang, Chao-Cheng Huang, Ming-Fong Lin

Journal Articles: Biochemistry & Molecular Biology

BACKGROUND: Prostate cancer (PCa) is the most commonly diagnosed solid tumor and the second leading cancer death in the United States, and also one of the major cancer-related deaths in Chinese. Androgen deprivation therapy (ADT) is the first line treatment for metastatic PCa. PCa ultimately relapses with subsequent ADT treatment failure and becomes castrate-resistant (CR). It is important to develop effective therapies with a surrogate marker towards CR PCa.

METHOD: Histone deacetylase (HDAC) inhibitors were examined to determine their effects in androgen receptor (AR)/cellular prostatic acid phosphatase (cPAcP)-positive PCa cells, including LNCaP C-33, C-81, C4-2 and C4-2B and MDA PCa2b …

Effect Of Sirna Pre-Exposure On Subsequent Response To Sirna Therapy, Hamidreza Montazeri Aliabadi, Parvin Mahdipoor, Cezary Kucharski, Nicole Chan, Hasan Uludag

Pharmacy Faculty Articles and Research

PURPOSE. An alternative cancer therapy based on RNA interference (RNAi) has shown considerable promise but the possibility of resistance development is not known. This study explored the possibility of therapeutic resistance against siRNA nanoparticles in human cancer cells. METHODS. Two approaches to siRNA treatment were undertaken using lipid-modified polyethylenimines, a single high concentration (shock) and repeated increasing concentrations (gradual). The targets were Mcl-1, RPS6KA5 and KSP in MDA-MB-435 cells. RESULTS. There was no evidence of resistance development in shock-treated cells, while the decrease in mRNA levels of targeted proteins was not as robust in naïve cells in gradual treatment. However, …

A Structural And Functional Comparison Between Infectious And Non-Infectious Autocatalytic Recombinant Prp Conformers, Geoffrey P. Noble, Daphne W. Wang, Daniel J. Walsh, Justin R. Barone, Michael B. Miller, Koren A. Nishina, Sheng Li, Surachai Supattapone

Dartmouth Scholarship

Infectious prions contain a self-propagating, misfolded conformer of the prion protein termed PrPSc. A critical prediction of the protein-only hypothesis is that autocatalytic PrPSc molecules should be infectious. However, some autocatalytic recombinant PrPSc molecules have low or undetectable levels of specific infectivity in bioassays, and the essential determinants of recombinant prion infectivity remain obscure. To identify structural and functional features specifically associated with infectivity, we compared the properties of two autocatalytic recombinant PrP conformers derived from the same original template, which differ by >105-fold in specific infectivity for wild-type mice. Structurally, hydrogen/deuterium exchange mass spectrometry (DXMS) studies revealed that solvent …

Novel Imidazopyridine Derivatives Possess Anti-Tumor Effect On Human Castration-Resistant Prostate Cancer Cells., Matthew A. Ingersoll, Anastesia S. Lyons, Sakthivel Muniyan, Napoleon D'Cunha, Tashika Robinson, Kyle Hoelting, Jennifer G. Dwyer, Xiu R. Bu, Surinder K. Batra, Ming-Fong Lin

Journal Articles: Biochemistry & Molecular Biology

Prostate cancer (PCa) is the second leading cause of cancer-related death afflicting United States males. Most treatments to-date for metastatic PCa include androgen-deprivation therapy and second-generation anti-androgens such as abiraterone acetate and enzalutamide. However, a majority of patients eventually develop resistance to these therapies and relapse into the lethal, castration-resistant form of PCa to which no adequate treatment option remains. Hence, there is an immediate need to develop effective therapeutic agents toward this patient population. Imidazopyridines have recently been shown to possess Akt kinase inhibitory activity; thus in this study, we investigated the inhibitory effect of novel imidazopyridine derivatives HIMP, …