Biological Phenomena, Cell Phenomena, and Immunity Commons^™

Asymmetric Deactivation Of Hiv-1 Gp41 Following Fusion Inhibitor Binding., Kristen M Kahle, H Kirby Steger, Michael J Root

Department of Biochemistry and Molecular Biology Faculty Papers

Both equilibrium and nonequilibrium factors influence the efficacy of pharmaceutical agents that target intermediate states of biochemical reactions. We explored the intermediate state inhibition of gp41, part of the HIV-1 envelope glycoprotein complex (Env) that promotes viral entry through membrane fusion. This process involves a series of gp41 conformational changes coordinated by Env interactions with cellular CD4 and a chemokine receptor. In a kinetic window between CD4 binding and membrane fusion, the N- and C-terminal regions of the gp41 ectodomain become transiently susceptible to inhibitors that disrupt Env structural transitions. In this study, we sought to identify kinetic parameters that …

Right-Handed 14-Helix In Β3-Peptides From L-Aspartic Acid Monomers, Kamaljit Kaur, Tara Sprules, Wael Soliman, Reem Beleid, Sahar Ahmed

Pharmacy Faculty Articles and Research

β-Peptides made from L-aspartic acid monomers form a new class of β³-peptides. Here we report the first three-dimensional NMR solution structure of a β³-hexapeptide (1) from L-aspartic acid monomers in 2,2,2-trifluoroethanol (TFE). We show that 1 forms a right-handed 14-helical structure in TFE. α-peptides from naturally occurring L-amino acids adopt a right-handed α-helix whereas β³-peptides formed from β³-amino acids derived from naturally occurring L-amino acids form left-handed 14-helices. The right-handed 14-helical conformation of 1 is a better mimic of α-peptide conformations. Using the NMR structure of 1 in TFE, we …

Dietary Canola Oil Suppressed Growth Of Implanted Mda-Mb 231 Human Breast Tumors In Nude Mice, W. Elaine Hardman

Biochemistry and Microbiology

Long chain omega 3 (n-3) fatty acids, eicosapentaenoic (EPA) and/or docosahexaenoic acid (DHA), have been shown to suppress growth of most cancer cells. In vivo, alpha linolenic acid (ALA, 18:3n-3) can be converted to EPA or DHA. We hypothesized that substituting canola oil (10% ALA) for the corn oil (1% ALA) in the diet of cancer bearing mice would slow tumor growth by increasing n-3 fatty acids in the diet. Sixty nude mice received MDA-MB 231 human breast cancer cells and were fed a diet containing 8% w/w corn oil until the mean tumor volume was 60 mm ³ . …

Uniaxial Stretch-Induced Regulation Of Mitogen-Activated Protein Kinase, Akt And P70s6 Kinase In The Ageing Fischer 344 × Brown Norway Rat Aorta, Kevin M. Rice, Devashish H. Desai, Deborah L. Preston, Paulette S. Wehner, Eric R. Blough

MIIR Faculty Research

The effects of ageing on the cardiovascular system contribute to substantial alterations in cellular morphology and function. The variables regulating these changes are unknown; however, one set of signalling molecules that may be of particular importance in mediating numerous cellular responses, including control of cell growth, differentiation and adaptation, are the proteins associated with the mitogen-activated protein kinase (MAPK) signalling systems. The MAPKs, in conjunction with the p70 S6k signalling cascade, have emerged as critical components for regulating numerous mechanotransduction-related cellular responses. Here we investigate the ability of uniaxial stretch to activate the MAPK and p70 S6k pathways in adult …

Su.32. Myelin-Specific Regulatory T Cells Accumulate In The Central Nervous System, But Fail To Suppress Pathogenic Effector T Cells At The Peak Of Autoimmune Inflammation [Abstract Only], Thomas Korn, Mohamed Oukka, Jay Reddy, Estelle Betelli, Amit Awasthi, Raymond Sobel, Kai Wucherpfennig, Vijay K. Kuchroo

Jay Reddy Publications

Treatment with ex vivo generated regulatory T cells (Treg) has been regarded as highly attractive therapeutic approach for autoimmune diseases. However, the dynamics and function of T-reg in autoimmunity are not well understood. Thus, we developed Foxp3gfp “knock-in” mice and myelin oligodendrocyte glycoprotein (MOG)35–55/IAb tetramers to track autoantigen-specific effector T cells (T-eff) and T-reg in vivo during experimental autoimmune encephalomyelitis, an animal model for multiple sclerosis. Following immunization with the encephalitogenic peptide MOG35–55 emulsified in complete Freund's adjuvant, MOG35–55-tetramer-reactive, Foxp3+ T-reg expanded in the peripheral lymphoid compartment and readily accumulated in the central nervous system (CNS), but did not prevent …

Or.76. Myelin Specific Regulatory T-Cells Expand From Naturally Occurring Regulatory T-Cells And Accumulate In The Cns During Eae [Abstract Only], Thomas Korn, Jay Reddy, Wenda Gao, Terry Strom, Mohamed Oukka, Vijay K. Kuchroo

Jay Reddy Publications

FoxP3 is a lineage specific marker for regulatory T-cells (Treg). We have generated FoxP3 knock-in (KI) mice by introducing a bicistronic GFP reporter into the endogenous FoxP3 locus, allowing us to faithfully track T-reg in vivo. Recently, we have also generated a MOG 35-55/IAb-tetramer. The combination of these two technologies enables us to study the in vivo behavior of myelin specific T-reg and effector T-cells (T-eff) during EAE. Upon immunization with MOG 35-55, we identified a population of MOG-tetramerreactive T-reg in the peripheral lymphoid compartment. T-reg trafficked to the CNS where they were readily detected as early as day 10 …

Or.107. Tim-1 Plays A Crucial Role In The Expansion Of Autopathogneic T-Cells And Regulation Of Autoimmunity [Abstract Only], Sheng Xioa, Nader Najafian, Jay Reddy, Monica Albin, Chen Zhu, Ana Anderson, Zheng Zhang, Cristina Gutierrez, Raymond Sobel, Dale Umetsu, Hideo Yagita, Hisaya Akiba, Mohamed Sayegh, Rosemarie Dekruyff, Vijay K. Kuchroo

Jay Reddy Publications

T-cell immunoglobulin and mucin (TIM) family Members are differentially expressed on Th1 and Th2 cells. Polymorphisms of TIM-1 have been associated with susceptibility to asthma; however, its role in regulating autoimmunity has not been studied. Here, we have used an agonistic antiTIM-1 antibody (Ab, Clone 3B3) which has previously been shown to costimulate T-cell activation and expansion, to analyze the role of TIM-1 in the development and regulation of experimental autoimmune encephalomyelitis (EAE). Treatment with 3B3 dramatically enhances the severity of EAE as well as the frequency of encephalitogenic CD4+ T-cells and the production of IFN-g and IL-17 by these …

Therapeutic Electromagnetic Field (Temf) And Gamma Irradiation On Human Breast Cancer Xenograft Growth, Angiogenesis And Metastasis, Ivan L. Cameron, Luzhe Sun, Nicholas Short, W. Elaine Hardman, C. Douglas Williams

Biochemistry and Microbiology

Background

The effects of a rectified semi-sinewave signal (15 mT amplitude, 120 pulses per second, EMF Therapeutics, Inc.) (TEMF) alone and in combination with gamma irradiation (IR) therapy in nude mice bearing a human MDA MB231 breast cancer xenograft were tested. Green fluorescence protein transfected cancer cells were injected into the mammary fat pad of young female mice. Six weeks later, mice were randomly divided into four treatment groups: untreated controls; 10 minute daily TEMF; 200 cGy of IR every other day (total 800 cGy); IR plus daily TEMF. Some mice in each group were euthanized 24 hours after the …

Endothelial Cell Pseudopods And Angiogenesis Of Breast Cancer Tumors, Ivan L. Cameron, Nicholas Short, Luzhe Sun, W. Elaine Hardman

Biochemistry and Microbiology

Background

A neoplastic tumor cannot grow beyond a millimeter or so in diameter without recruitment of endothelial cells and new blood vessels to supply nutrition and oxygen for tumor cell survival. This study was designed to investigate formation of new blood vessels within a human growing breast cancer tumor model (MDA MB231 in mammary fat pad of nude female mouse). Once the tumor grew to 35 mm³, it developed a well-vascularized capsule. Histological sections of tumors greater than 35 mm³were stained with PAS, with CD-31 antibody (an endothelial cell maker), or with hypoxia inducible factor 1α …

Dietary Omega-3 Fatty Acids And Ionizing Irradiation On Human Breast Cancer Xenograft Growth And Angiogenesis, W. Elaine Hardman, Luzhe Sun, Nicholas Short, Ivan L. Cameron

Biochemistry and Microbiology

Background

The effects of an omega-3 (n-3) fatty acid enriched diet alone and in combination with gamma irradiation (IR) therapy in nude mice bearing a human MDA-MB231 breast cancer xenograft were tested. The cancer cells were injected into the mammary fat pad of young female mice. Six weeks later, mice were randomly divided into two diet groups: 1) mice with 10% corn oil (rich in omega 6 fatty acids) in their food, 2) mice consuming a 10% fat diet that was enriched in n-3 fatty acids. After two weeks on the diet, treatment with 200 cGy of IR every second …

Myelin Proteolipid Protein-Specific Cd4+ Cd25+ Regulatory Cells Mediate Genetic Resistance To Experimental Autoimmune Encephalomyelitis, Jay Reddy, Zsolt Illés, Xingmin Zhang, Jeffrey Encinas, Jason Pyrdol, Lindsay Nicholson, Raymond A. Sobel, Kai W. Wucherpfennig, Vijay K. Kuchroo, James P. Allison

Jay Reddy Publications

SJL mice are highly susceptible to experimental autoimmune encephalomyelitis (EAE) induced with myelin proteolipid protein (PLP) peptide 139–151, whereas H-2 congenic B10.S mice are resistant. Immunodominance and susceptibility to EAE are associated with a high precursor frequency of PLP 139–151-specific T cells in the naive repertoire of SJL mice. To understand the mechanism of EAE resistance in B10.S mice, we determined the precursor frequency of PLP 139–151-reactive T cells in both strains by using IA^s/PLP 139–151 tetramers. SJL and B10.S mice had similar frequencies of tetramer-reactive T cells in the naive peripheral repertoire. However, in SJL mice, the …

Modified Amino Acid Copolymers Suppress Myelin Basic Protein 85–99-Induced Encephalomyelitis In Humanized Mice Through Different Effects On T Cells, Zsolt Illés, Joel N.H. Stern, Jay Reddy, Hanspeter Waldner, Marcin P. Mycko, Celia F. Brosnan, Stephan Ellmerich, Daniel M. Altmann, Laura Santambrogio, Jack L. Strominger, Vijay K. Kuchroo

Jay Reddy Publications

A humanized mouse bearing the HLA-DR2 (DRA/DRB1*1501) pro- tein associated with multiple sclerosis (MS) and the myelin basic protein (MBP) 85–99-specific HLA-DR2-restricted T cell receptor from an MS patient has been used to examine the effectiveness of modified amino acid copolymers poly(F,Y,A,K)n and poly- (V,W,A,K)n in therapy of MBP 85–99-induced experimental auto-immune encephalomyelitis (EAE) in comparison to Copolymer 1 [Copaxone, poly(Y,E,A,K)n]. The copolymers were designed to optimize binding to HLA-DR2. Vaccination, prevention, and treatment of MBP-induced EAE in the humanized mice with copolymers FYAK and VWAK ameliorated EAE more effectively than Copolymer 1, reduced the number of pathological lesions, and …

Waddington’S Widget: Hsp90 And The Inheritance Of Acquired Characters, Douglas M. Ruden, Mark D. Garfinkel, Vincent E. Sollars, Xiangyi Lu

Biochemistry and Microbiology

Conrad Waddington published an influential model for evolution in his 1942 paper, Canalization of Development and Inheritance of Acquired Characters. In this classic, albeit controversial, paper, he proposed that an unknown mechanism exists that conceals phenotypic variation until the organism is stressed. Recent studies have proposed that the highly conserved chaperone Hsp90 could function as a “capacitor,” or an “adaptively inducible canalizer,” that masks silent phenotypic variation of either genetic or epigenetic origin. This review will discuss evidence for, and arguments against, the role of Hsp90 as a capacitor for morphological evolution, and as a key component of what …

High Dietary Level Of Synthetic Vitamin E On Lipid Peroxidation, Membrane Fatty Acid Composition And Cytotoxicity In Breast Cancer Xenograft And In Mouse Host Tissue, Ivan L. Cameron, Jesus Munoz, Christopher J. Barnes, W. Elaine Hardman

Biochemistry and Microbiology

Background

d-α-tocopherol is a naturally occurring form of vitamin E not previously known to have antitumor activity. Synthetic vitamin E (sE) is a commonly used dietary supplement consisting of a mixture of d-α-tocopherol and 7 equimolar stereoisomers. To test for antilipid peroxidation and for antitumor activity of sE supplementation, two groups of nude mice bearing a MDA-MB 231 human breast cancer tumor were fed an AIN-76 diet, one with and one without an additional 2000 IU/kg dry food (equivalent to 900 mg of all-rac-α-tocopherol or sE). This provided an intake of about 200 mg/kg body weight per day. The mice …

Roles And Regulation Of Nf-Κb In Platelet-Derived Growth Factor Transformed Cells, Takeshi Shimamura

Dissertations

Platelet-derived growth factor (PDGF) is overexpressed in various cancer cells and the overexpression may be correlated with the prognosis of several types of cancers. Binding of PDGF to its receptors induces receptor dimerization and subsequent autophosphorylation of tyrosine residues in the receptor’s cytoplasmic domains. The phosphorylated tyrosine residues interact with the secondary signaling molecules to initiate signaling cascades that trigger cellular changes by affecting downstream effectors. In our recent publication, we have shown that a NF-κB mediates the transformation of mouse fibroblast cells overexpressing PDGF B chain. Though there is a significant correlation between PDGF stimulation and NF-κB activity, it …

Regulation Of Retinoic Acid Receptor Α By Protein Kinase C In B16 Mouse Melanoma Cells, Goran Boskovic, Dinakar Desai, Richard M. Niles

Biochemistry and Microbiology

We have previously found that retinoic acid stimulates the expression of protein kinase Cα (PKC) in B16 mouse melanoma cells. Because it has been reported that PKC can phosphorylate retinoic acid receptor (RAR) and alter its function, we determined whether changes in the level and/or activity of PKC could affect the expression or function of the RAR in B16 melanoma. Using in vivophosphorylation and band shift techniques, we could not demonstrate that altering PKC activity and/or protein level changed thein vivo phosphorylation of RARα. However activation of PKC resulted in increased RARα protein. Increased receptor protein correlated with …

Therapeutic Electromagnetic Field Effects On Angiogenesis And Tumor Growth, C. Douglas Williams, Marko S. Markov, W. Elaine Hardman, Ivan L. Cameron

Biochemistry and Microbiology

Background: A new approach to cancer therapy based on the application of therapeutic electromagnetic fields (TEMF) has been developed by EMF Therapeutics, Inc., Chattanooga, TN, USA. This study was designed to assess the effect of TEMF on tumor vascularization and growth of murine 16/C mammmary adenocarcinoma cells in C3H/HeJ mice.

Materials and Methods: Implanted tumors were allowed to grow for seven days until the tumor volume reached 100 mm3 before treatment was started. Mice (20 per control, 10 per EMF exposed group) received treatment (10 minutes per day with 0, 10 mT, 15 mT or 20 mT) with a 120 …

Immunologic Effects Of Gliotoxin In Rats: Mechanisms For Prevention Of Autoimmune Diabetes Mellitus, Honggang Liu, Susan H. Jackman, Henry Driscoll, Bryan Larsen

Biochemistry and Microbiology

Various fungal products, such as gliotoxin (GT), have immunomodulating activity, a fact exploited previously by our group for prevention of autoimmune diabetes mellitus in BB/Wor rats. To understand better the immunologic effects in GT-treated rats, splenocytes from 65-day-old prediabetic diabetes-prone rats were phenotypically characterized after chronic treatment with GT. A parallel study examined the direct effects of GT on splenocyte preparations incubated with the mycotoxin. In vitro treatment of splenocytes with GT revealed relative decreases in CD4+ and increases in CD8+ T-cell subsets, whereas in vivo treatment with GT did not result in detectable alterations in relative CD4+ and CD8+ …

Effect Of Receptor-Selective Retinoids On Growth And Differentiation Pathways In Mouse Melanoma Cells, Sejal H. Desai, Goran Boskovic, Linda L. Eastham, Marcia Dawson, Richard M. Niles

Biochemistry and Microbiology

Treatment of B16 mouse melanoma cells with all-trans-retinoic acid (ATRA) results in inhibition of cell proliferation and induction of differentiation. Accompanying these events is an induction of retinoic acid receptor β (RARβ) expression, an increase in protein kinase Cα (PKCα) expression, and enhanced activator protein-1 (AP-1) transcriptional activity. These cells express nuclear RARα and RARγ and nuclear retinoid X receptors (RXR) α and β constitutively. We tested the ability of receptor-selective retinoids to induce the biochemical changes found in ATRA-treated melanoma cells and also tested their effectiveness in decreasing anchorage-dependent and -independent growth. The RXR-selective ligand (2E,4E)-6-(5,6,7,8-tetrahydro-3,5,5,8,8-pentamethyl-2-naphthalenyl)-3,7-dimethyl-2,4,6-octatrienoic acid (SR11246) was …