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 …

Protection Against Mucosal Shiv Challenge By Peptide And Helper-Dependent Adenovirus Vaccines, Eric A. Weaver, Pramod N. Nehete, Bharti P. Nehete, Stephanie J. Buchl, Donna Palmer, David C. Montefiori, Philip Ng, K. Jagannadha Sastry, Michael A. Barry

Nebraska Center for Virology: Faculty Publications

Groups of rhesus macaques that had previously been immunized with HIV-1 envelope (env) peptides and first generation adenovirus serotype 5 (FG-Ad5) vaccines expressing the same peptides were immunized intramuscularly three times with helperdependent adenovirus (HD-Ad) vaccines expressing only the HIV-1 envelope from JRFL. No gag, pol, or other SHIV genes were used for vaccination. One group of the FG-Ad5- immune animals was immunized three times with HD-Ad5 expressing env. One group was immunized by serotype-switching with HD-Ad6, HD-Ad1, and HD-Ad2 expressing env. Previous work demonstrated that serum antibody levels against env were significantly higher in the serotype-switched group than in …

Use Of Phage Display To Isolate Specifi C Human Monoclonal Antibody Fragments Against A Potential Target For Multiple Myeloma, Pei Xiong Liew, Feng Ge, Charles A. Gullo, Gerrard Kh Teoh, William Yk Hwang

Biochemistry and Microbiology

Introduction: Multiple myeloma (MM), a malignancy of plasma cells, accounts for 10% of all haematological malignancies and is currently incurable. Although it can be treated, the disease tends to relapse after several years and becomes increasingly resistant to conventional therapy. Investigations into using humoral therapy for MM are now underway with a view that novel therapeutic agents may provide a more targeted therapy for MM.

Materials and Methods: Here, phage display, a faster and more efficient method compared to classical hybridoma fusion technology, was used as a proof-of-concept to isolate several single-chain Fragment variables (scFv) against Ku86.

Results …

The Effect Of Endothelin-1 On The Expression Of Cdk Inhibitors P21 & P27 In Bovine Corneal Endothelial Cells, Lakshmi Reddy Bollu

Masters Theses & Specialist Projects

Mammalian corneal endothelial cells are considered to be non-proliferative due to the arrest of cells at the G1 phase of the cell cycle. The purpose of this study was to determine whether the down regulation of cyclin dependant kinase inhibitors (p21cip1 and p27kip1) levels by Endothelin-1 (ET-1), would overcome the G1 phase arrest and promote cell cycle progression and proliferation in cultured BCECs (Bovine corneal endothelial cells). BCECs were isolated from bovine corneas and cultured in DMEM supplemented with 10% serum. 5-Bromo 2-deoxy Uridine (BrdU) incorporation was determined in serum starved cultures in 24-well plates as a measure of cell …

Comparison Of Replication-Competent, First Generation, And Helper-Dependent Adenoviral Vaccines, Eric A. Weaver, Pramod N. Nehete, Stephanie S. Buchl, Julien S. Senac, Donna Palmer, Philip Ng, K. Jagannadha Sastry, Michael A. Barry

Nebraska Center for Virology: Faculty Publications

All studies using human serotype 5 Adenovirus (Ad) vectors must address two major obstacles: safety and the presence of pre-existing neutralizing antibodies. Helper-Dependent (HD) Ads have been proposed as alternative vectors for gene therapy and vaccine development because they have an improved safety profile. To evaluate the potential of HD-Ad vaccines, we compared replication-competent (RC), first-generation (FG) and HD vectors for their ability to induce immune responses in mice. We show that RC-Ad5 and HD-Ad5 vectors generate stronger immune responses than FG-Ad5 vectors. HD-Ad5 vectors gave lower side effects than RC or FG-Ad, producing lower levels of tissue damage and …

Positional Information Generated By Spatially Distributed Signaling Cascades., Javier Muñoz-García, Zoltan Neufeld, Boris N Kholodenko

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

The temporal and stationary behavior of protein modification cascades has been extensively studied, yet little is known about the spatial aspects of signal propagation. We have previously shown that the spatial separation of opposing enzymes, such as a kinase and a phosphatase, creates signaling activity gradients. Here we show under what conditions signals stall in the space or robustly propagate through spatially distributed signaling cascades. Robust signal propagation results in activity gradients with long plateaus, which abruptly decay at successive spatial locations. We derive an approximate analytical solution that relates the maximal amplitude and propagation length of each activation profile …

The P53-Induced Siva-1 Plays A Significant Role In Cisplatin-Mediated Apoptosis, John L. Barkinge, Radhika Gudi, Hawkins Sarah, Fei Chu, Alip Borthakur, Bellur S. Prabhakar

Clinical & Translational Sciences

Background: The pro-apoptotic protein Siva-1 functions in both extrinsic and intrinsic cell death signaling; however, the exact contribution of the endogenous Siva-1 to DNA damage-induced apoptosis is unclear. Using cisplatin, a chemotherapeutic drug, to induce DNA damage and cell death, we determined the role of Siva-1.

Methods: Cisplatin treated HCT116 colorectal carcinoma cells (p53+/+ and -/-) were used in the study. With the help of recombinant lentivirus that can express siSiva (siRNA that specifi cally targets Siva-1), we also generated Siva-1 knockdown HCT116 cells. Apoptosis was determined by tetramethyl rhodamine methyl ester (TMRM) staining and propidium iodide (PI) staining.

Results: …

Efficacy Of Deferasirox In Preventing Complications Of Iron Overload In The Iron Overloaded Gerbil, Rabaa M. Al-Rousan

Theses, Dissertations and Capstones

Iron overload is a significant, world-wide problem that results in several chronic diseases including cardiovascular, hepatic and pancreatic complications.The newly developed, orally effective, iron chelating agent deferasirox is thought to offer tremendous promise as an alternative to deferoxamine. However, the efficacy and safety profile of deferasirox is not yet clear. In the present study, the efficacy of deferasirox in removing iron from target tissues has been examined using the gerbil model of iron overload. Deferasirox administration resulted in a significant reduction of iron from cardiac and hepatic tissue. In addition deferasirox reduced iron induced increase in cardiac and hepatic oxidative …

Identification And Characterization Of Novel Sir3/Mecp2-Chromatin Interactions, Nicholas L. Adkins

Theses, Dissertations and Capstones

The eukaryotic genome is packaged into chromosomes that are made up of a highly organized and heavily regulated structure called chromatin. The proteins involved in the compaction of DNA into this condensed state are mostly understood at the level of the structure of the nucleosome. The higher order arrangement of chromatin and how it effects gene regulation is only partially understood and characterized. The compaction of nucleosomal arrays into 30-nm and higher structures are partially the responsibility of architectural, or structural, chromatin associated proteins. The following dissertation analyzes the individual chromatin contributions of two well studied architectural proteins, the yeast …

Stat5 Regulation Of Bcl10 Parallels Constitutive Nfkappab Activation In Lymphoid Tumor Cells., Zsuzsanna S Nagy, Matthew J Lebaron, Jeremy A Ross, Abhisek Mitra, Hallgeir Rui, Robert A Kirken

Department of Cancer Biology Faculty Papers

BACKGROUND: Signal Transducer and Activator of Transcription 5 A and B (STAT5) are key survival factors in cells of the lymphoid lineage. Identification of novel, tissue-specific STAT5 regulated genes would advance the ability to combat diseases due to aberrant STAT5 signaling. In the present work a library of human STAT5 bound genomic elements was created and validated. RESULTS: Of several STAT5 responsive genomic regulatory elements identified, one was located within the first intron of the human BCL10 gene. Chromatin immuno-precipitation reactions confirmed constitutive in vivo STAT5 binding to this intronic fragment in various human lymphoid tumor cell lines. Interestingly, non-phosphorylated …

X4 Human Immunodeficiency Virus Type 1 Gp120 Down-Modulates Expression And Immunogenicity Of Codelivered Antigens, Avi-Hai Hovav, Michael Santosuosso, Maytal Bivas-Benita, Andre Plair, Alex Cheng, Mazal Elnekave, Elda Righi, Tao Chen, Satoshi Kashiwagi, Michael W. Panas, Shi-Hua Xiang, Karina Furmanov, Norman L. Letvin, Mark C. Poznansky

Nebraska Center for Virology: Faculty Publications

In order to increase the immune breadth of human immunodeficiency virus (HIV) vaccines, strategies such

as immunization with several HIV antigens or centralized immunogens have been examined. HIV-1 gp120

protein is a major immunogen of HIV and has been routinely considered for inclusion in both present and

future AIDS vaccines. However, recent studies proposed that gp120 interferes with the generation of immune

response to codelivered antigens. Here, we investigate whether coimmunization with plasmid-encoded gp120

alters the immune response to other coadministered plasmid encoded antigens such as luciferase or ovalbumin

in a mouse model. We found that the presence of gp120 …

Identification And Characterization Of A New Kaposi’S Sarcoma-Associated Herpesvirus Replication And Transcription Activator (Rta)- Responsive Element Involved In Rta-Mediated Transactivation, Hui-Ju Wen, Veenu Minhas, Charles Wood

Nebraska Center for Virology: Faculty Publications

Kaposi’s sarcoma-associated herpesvirus (KSHV) replication and transcription activator (RTA) is well established as a key transcriptional activator that regulates the KSHV life cycle from latency to lytic replication. It is expressed immediately after infection and activates a number of viral genes leading to virus replication. The RTA-responsive element (RRE) in the RTA target gene promoters is critical for RTA to mediate this transactivation. A number of non-conserved RREs have been identified in various RTA-responsive promoters, and AT-rich sequences have been proposed to serve as RTA targets, but no consensus RRE sequence has been identified so far. Two nonconserved RREs (RRE1 …

Use Of Average Mutual Information For Studying Changes In Hiv Populations, Khalid Sayood, Federico Hoffman, Charles Wood

Nebraska Center for Virology: Faculty Publications

Average mutual information (AMI) has been used in a number of applications in bioinformatics. In this paper we present its use to study genetic changes in populations; in particular populations of HIV viruses. Disease progression of HIV-1 infection in infants can be rapid resulting in death within the the first year, or slow, allowing the infant to survive beyond the first year. We study the development of rapid and slow progressing HIV population using AMI charts based on average mutual information among amino acids in the env gene from a population of 1142 clones derived from seven infants with slow …

Comparison Of Replication-Competent, First Generation, And Helper-Dependent Adenoviral Vaccines, Eric A. Weaver, Pramod N. Nehete, Stephanie S. Buchl, Julien S. Senac, Donna Palmer, Philip Ng, K. Jagannadha Sastry, Michael A. Barry

Nebraska Center for Virology: Faculty Publications

All studies using human serotype 5 Adenovirus (Ad) vectors must address two major obstacles: safety and the presence of pre-existing neutralizing antibodies. Helper-Dependent (HD) Ads have been proposed as alternative vectors for gene therapy and vaccine development because they have an improved safety profile. To evaluate the potential of HD-Ad vaccines, we compared replication-competent (RC), first-generation (FG) and HD vectors for their ability to induce immune responses in mice. We show that RC-Ad5 and HD-Ad5 vectors generate stronger immune responses than FG-Ad5 vectors. HD-Ad5 vectors gave lower side effects than RC or FG-Ad, producing lower levels of tissue damage and …

Human Ubc9 Contributes To Production Of Fully Infectious Human Immunodeficiency Virus Type 1 Virions, Tareq Jaber, Christopher R. Bohl, Gentry L. Lewis, Charles Wood, John T. West Jr., Robert A. Weldon Jr.

Nebraska Center for Virology: Faculty Publications

Ubc9 was identified as a cellular protein that interacts with the Gag protein of Mason-Pfizer monkey virus. We show here that Ubc9 also interacts with the human immunodeficiency virus type 1 (HIV-1) Gag protein and that their interaction is important for virus replication. Gag was found to colocalize with Ubc9 predominantly at perinuclear puncta. While cells in which Ubc9 expression was suppressed with RNA interference produced normal numbers of virions, these particles were 8- to 10-fold less infectious than those produced in the presence of Ubc9. The nature of this defect was assayed for dependence on Ubc9 during viral assembly, …

Expression Of Hpv16 E5 Produces Enlarged Nuclei And Polyploidy Through Endoreplication, Lulin Hu, Tamara A. Potapova, Shibo Li, Susannah Rankin, Gary J. Gorbsky, Peter C. Angeletti, Brian P. Ceresa

Nebraska Center for Virology: Faculty Publications

Anogenital cancers and head and neck cancers are causally-associated with infection by high-risk

human papillomavirus (HPV). The mechanism by which high-risk HPVs contribute to

oncogenesis is poorly understood. HPV16 encodes three genes (HPV16 E5, E6, and E7) that can

transform cells when expressed independently. HPV16 E6 and E7 have well-described roles

causing genomic instability and unregulated cell cycle progression. The role of HPV16 E5 in cell

transformation remains to be elucidated. Expression of HPV16 E5 results in enlarged, polyploid

nuclei that are dependent on the level and duration of HPV16 E5 expression. Live-cell imaging

data indicate these changes do not …

Human Papillomavirus 16 E5 Induces Bi-Nucleated Cell Formation By Cell-Cell Fusion, Lulin Ha, Kendra Plafker, Valeriya Vorozhoko, Rosemary E. Zuna, Marie H. Hanigan, Gary J. Gorbsky, Scott M. Plafker, Peter C. Angeletti, Brian P. Ceresa

Nebraska Center for Virology: Faculty Publications

Human Papillomaviruses (HPV) 16 is a DNA virus encoding three oncogenes – E5, E6, and E7. The E6 and E7 proteins have well-established roles as inhibitors of tumor suppression, but the contribution of E5 to malignant transformation is controversial. Using spontaneously immortalized human keratinocytes (HaCaT cells), we demonstrate that expression of HPV16 E5 is necessary and sufficient for the formation of bi-nucleated cells, a common characteristic of precancerous cervical lesions. Expression of E5 from non-carcinogenic HPV6b does not produce bi-nucleate cells. Video microscopy and biochemical analyses reveal that bi-nucleates arise through cell-cell fusion. Although most E5-induced bi-nucleates fail to propagate, …

A Comparative Study Of Hiv-1 Clade C Env Evolution In A Zambian Infant With An Infected Rhesus Macaque During Disease Progression, For Yue Tso, Federico G. Hoffmann, Damien C. Tully, Philippe Lemey, Robert A. Rasmussen, Hong Zhang, Ruth M. Ruprecht, Charles Wood

Nebraska Center for Virology: Faculty Publications

Objective—To evaluate whether HIV-1 clade C (HIV-C) envelope variations that arise during disease progression in rhesus macaque model reflect changes that occur naturally in human infection.

Design—An infant macaque was infected with SHIV-1157i, an R5 tropic clade C SHIV (SHIV-C) which expresses a primary HIV-C envelope derived from an infected human infant, and monitored over a five-year period. Genetic variation of the V1-V5 envelope region, which is the main target for humoral immune responses, derived from the infected macaque and infant was examined.

Methods—V1-V5 envelope region were cloned and sequenced from longitudinal PBMC samples collected from the infected macaque and …

Protection Against Mucosal Shiv Challenge By Peptide And Helper-Dependent Adenovirus Vaccines, Eric A. Weaver, Pramod N. Nehete, Bharti P. Nehete, Stephanie J. Buchl, Donna Palmer, David C. Montefiori, Philip Ng, K. Jagannadha Sastry, Michael A. Barry

Nebraska Center for Virology: Faculty Publications

Groups of rhesus macaques that had previously been immunized with HIV-1 envelope (env) peptides and first generation adenovirus serotype 5 (FG-Ad5) vaccines expressing the same peptides were immunized intramuscularly three times with helper- dependent adenovirus (HD-Ad) vaccines expressing only the HIV-1 envelope from JRFL. No gag, pol, or other SHIV genes were used for vaccination. One group of the FG-Ad5- immune animals was immunized three times with HD-Ad5 expressing env. One group was immunized by serotype-switching with HD-Ad6, HD-Ad1, and HD-Ad2 expressing env. Previous work demonstrated that serum antibody levels against env were significantly higher in the serotype-switched group than …