Cell Biology Commons^™

Attenuated Responses To Inflammatory Cytokines In Mouse Embryonic Stem Cells: Biological Implications And The Molecular Basis, Bohan Chen

Master's Theses

Embryonic stem cells (ESCs) have attracted intense interest due to their great potential for regenerative medicine. However, their immune property is an overlooked but a significant issue that needs to be thoroughly investigated not only to resolve the concern for therapeutic applications but also for further understanding the early stage of organismal development. Recent studies demonstrated that ESCs are deficient in innate immune responses to viral/bacterial infections and inflammatory cytokines. Inflammatory conditions generally inhibit cell proliferation, which could be detrimental to ESCs, since cell proliferation is their dedicated task during early embryogenesis. Thus, I hypothesize that the attenuated innate immunity …

Embryonic Lethality Of Cranial Neural Crest Deletion Of Cdc73, Lilia Shen

Honors Scholar Theses

Hyperparathyroidism-jaw tumor (HPT-JT) syndrome is a disease characterized by parathyroid tumors, renal cysts or tumors, uterine tumors, and ossifying jaw fibromas. The cause of this syndrome is linked to a tumor suppressor gene called Cdc73, which encodes the protein product parafibromin. The loss of proper expression of Cdc73/parafibromin is implicated in the development of the tumors typical of HPT-JT, although the exact mechanisms of tumorigenesis are unclear. In particular, not much is understood about the development of ossifying fibromas (OF) of the jaw in this syndrome. OF is a benign bone neoplasm that can affect the mandible and …

The Signaling Pathways Of Metallothionein-Mediated Chemotaxis In Breast Cancer, Jennifer Messina

Honors Scholar Theses

Metallothionein (MT) is a small, thiol rich protein released into the extracellular environment in response to stress. Elevated expression of MT has been linked to many inflammatory diseases including inflammatory bowel diseases, diabetes, and cancer. In breast cancer, high expression of MT has been associated with poor patient prognosis. Previous studies have shown that MT acts as a chemoattractant in lymphocytes, and that UC1MT, a monoclonal anti-MT antibody, can block this chemotactic response. In addition, it has been shown that both Cholera toxin and Pertussis toxin, which are known antagonists of G-protein coupled receptors, can inhibit MT-mediated chemotaxis. Here, I …

Spatial Reorganization Of Histone-Like Nucleoid Structuring Proteins Caused By Silver Nanoparticles, Meaad Alqahtany

Graduate Theses and Dissertations

Silver nanoparticles (AgNPs) and ions (Ag+) can be the new generation of antibiotics due to their antimicrobial effects against bacteria and other microbes. Many studies have shown that AgNPs and suppress the growth of bacteria and damage the cell walls of the microbes; therefore, treating bacterial cells with AgNPs may be a promising method to terminate multi-resistant bacteria. In this work, the effect of AgNPs with two different surface coatings on the spatial reorganization of histone-like nucleoid structuring (H-NS) proteins in Escherichia coli bacteria was investigated using quantitative super-resolution fluorescence microscopy to understand the toxicity and antimicrobial mechanism of AgNPs. …

Platiscity Of C. Elegans Germline Stem Cells Under Nutritional And Metabolic Stress, Kenneth Trimmer

Dissertations and Theses (Open Access)

Stem cells are integral for tissue maintenance and fertility. Therefore, understanding how stem cells are regulated under stress is imperative. When confronted with acute starvation, stem cells must conserve energy and metabolites to cope with the lack of an external source. Caenorhabditis elegans germline stem cells (GSCs) are an excellent model for studying stem cell properties and regulation as they can divide throughout the life of the organism. While GSCs are an adult stem cell population, their cell cycle structure more closely mimics mouse and human embryonic stem cells with short G1 and long S phases. In this thesis, I …

Thiol-Based Misfolding: Linking Redox Balance To Cytosolic Proteostasis, Ford Amy

Dissertations and Theses (Open Access)

The eukaryotic cytosolic proteome is vulnerable to changes in proteostatic and redox balance caused by temperature, pH, oxidants and xenobiotics. Cysteine-containing proteins are especially at risk as the thiol side chain is subject to oxidation, adduction and chelation by thiol-reactive compounds. All of these thiol-modifiers have been demonstrated to induce the heat shock response and recruit protein chaperones to sites of presumed protein aggregation in the budding yeast Saccharomyces cerevisiae. However, endogenous targets of thiol stress toxicity responsible for these outcomes are largely unknown. Furthermore, I hypothesize proteins identified as redox-active are prone to misfolding and aggregation by thiol-specific …

Characterization Of Microtubule Organizing Centers In The Genus Protostelium, Including Evolutionary Implications, Ethan Taylor Ozment

Graduate Theses and Dissertations

Microtubule organizing centers (MTOCs) are cellular regions of microtubule nucleation. The best known MTOCs are those associated with the centrosome, but several non-centrosomal MTOCs are known in eukaryotes, especially in land plants. MTOCs are poorly characterized across the breadth of amoebozoan diversity, but are well-known in certain amoebozoan lineages, including the genus of protosteloid slime molds Protostelium. The structure of the MTOC is known for two non-ciliated species, P. nocturnum and P. mycophaga, as well as P. aurantium, which can reversibly become ciliated under appropriate conditions. P. nocturnum and P. mycophaga have acentriolar centrosomal MTOCs while P. aurantium has a …

Targeting Sec61Α By Ipomoeassin F Leads To Highly Cytotoxic Effect, Zhijian Hu

Graduate Theses and Dissertations

Ipomoeassin F is a flagship congener of a resin glycoside family that inhibits growth of many tumor cell lines with only single-digital nanomolar IC50 values. However, biological and pharmacological mechanisms of ipomoeassin F have been undefined. To facilitate exploration of the biological and pharmacological properties, we performed sophisticate SAR (Structure–activity relationship) studies of ipomoeassin F to understand its pharmacophore and structure properties so that we can design favorable probes for further biological investigation. By applying appropriate deviates that possess fluorescent groups and similar bio-activity, the target protein was found to be localized in endoplasmic reticulum (ER). Through biotin affinity pull …

Hormone Signaling, Gene Expression, And Mitochondrial Hormone Receptor Expression In Avian Muscle (Cells), Kentu Rushadd Lassiter

Graduate Theses and Dissertations

Mitochondria are vital to the proper growth and function of muscle cells since they’re responsible for the majority of ATP production used for cellular energy. Previous studies have investigated how differences in mitochondrial function affects feed efficiency (FE) in broilers phenotyped for High and Low FE. Low FE broilers have been shown to have increased levels of reactive oxygen species (ROS), thus contributing to higher levels of oxidative stress and damage seen in these birds. Global gene and protein expression studies conducted on breast muscle of the High FE and Low FE phenotypes have suggested that differences in mitochondrial function …

A Novel Kinesin Adapter Directly Mediates Dendritic Mrna Localization During Synapse Development, Hao Wu

Dissertations, Theses, and Capstone Projects

Cytoskeleton based active transport with motor proteins is essential for mRNA localization and local protein translation in animal cells, yet how mRNA granules interact with motor proteins remains poorly understood. Using an unbiased screen for interaction between mRNA binding proteins (RBP) and motor proteins, we identified protein interacting with APP tail 1 (PAT1) as a potential direct adapter between the β-actin mRNA Zipcode-binding protein 1 (ZBP1) and Kinesin-1 motor complex.

Mouse PAT1 is similar to the Kinesin Light Chain (KLC) in amino acid sequence and binds directly to KLC. High-resolution images from structured illumination microscopy (SIM) indicates that synaptic stimulation …

The 5-Ht1a-R Knockout Mouse As A Model Of Later Life Anxiety Disorders: Implications For Sex Differences, Tatyana Budylin

Dissertations, Theses, and Capstone Projects

Anxiety affects nearly twice as many women as it affects men across all cultures and economic groups. Importantly, girls have a higher chance of inheriting anxiety disorders than boys, and many anxiety disorders appear at a very young age. However, little is known about sex differences in brain and behavioral development and how they relate to anxiety in adulthood. Serotonin 1A receptor (5-HT_1A-R) mediated signaling has been implicated in depression and anxiety, however most studies that focus on the involvement of the 5-HT_1A-R have been conducted in adults. Little is known about how the 5-HT_{1A …}

The Effects Of Vascular Endothelial Growth Factor On The Characteristics Of Pluripotent Dental Pulp Stem Cells, Cale Forgues

UNLV Theses, Dissertations, Professional Papers, and Capstones

Many believe that stem cells hold the key to regenerative medicine. Therefore, research with stem cells has become increasingly popular over the years. Three specific groups of study have become present in literature. The first group has focused much of their research on harvesting and cultivating stem cell lines to retain their pluripotent ability. Stem cells can be tricky to cultivate and preserve over time as they will often differentiate or die. Another group examines the specific characteristics that a pluripotent stem cell has and how to retain, or even create, a cell with pluripotent potential. Lastly, the third group …

Delineation Of Events In Centripetal Migration During Drosophila Oogenesis, Travis Tait Parsons

UNLV Theses, Dissertations, Professional Papers, and Capstones

All multicellular organisms initially start out as a single cell. This cell must use the genetic information encoded in its DNA to multiply in number and build itself into a complex multicellular organism. How this process occurs is the focus of developmental biology, a field that seeks to understand how a combination of genetic information and environmental conditions shape a cell from its beginnings as a zygote all the way to maturity. A fundamental part of this process is the ability of cells to work together in order to build complex tissues and organs. Cells achieve this coordination by using …

The Role And Regulation Of Alternative Polyadenylation In The Dna Damage Response, Michael R. Murphy

Dissertations, Theses, and Capstone Projects

Cellular homeostasis is achieved by the dynamic flux in gene expression. Post-transcriptional regulation of coding and non-coding RNA offers a fast method of adapting to a changing cellular environment, including deadenylation, microRNA (miRNA) pathway, and alternative polyadenylation (APA). In this dissertation, I explored some of the mechanisms involved in the post-transcriptional regulation of gene expression. The main hypothesis in these studies is that a single APA event after DNA damage is governed by specific conditions and factors outside of current known regulators of APA, and that the resultant transcript has a role in the DNA damage response (DDR). My aims …

The Molecular Mechanisms Underlying The Cancer Killing Effect Of Interleukin-24, Leah Eshanie Persaud

Dissertations, Theses, and Capstone Projects

Interleukin-24 (IL-24) is an immunomodulatory cytokine that also displays specific anti-tumor effects across many cancer cell types. The tumor suppressor activities of IL-24 include inhibition of angiogenesis, metastasis, toxic autophagy, cancer-specific apoptosis, and sensitization to traditional cancer treatments like chemotherapy and radiation. Overexpression of IL-24 can selectively induce apoptosis in various cancer cells while having no adverse effects on normal cells. Due to this favorable killing effect, IL-24 is currently in phase II clinical trials. There is accumulating evidence that IL-24’s anti-cancer activity is primarily through the endoplasmic reticulum (ER) stress pathway but other pathways leading to cell death are …

Sensory Primary Cilium Is A Responsive Camp Microdomain In Renal Epithelia, Rinzhin T. Sherpa, Ashraf M. Mohieldin, Rajasekharreddy Pala, Dagmar Wachten, Rennolds S. Ostrom, Surya M. Nauli

Pharmacy Faculty Articles and Research

Primary cilia are hair-like cellular extensions that sense microenvironmental signals surrounding cells. The role of adenylyl cyclases in ciliary function has been of interest because the product of adenylyl cyclase activity, cAMP, is relevant to cilia-related diseases. In the present study, we show that vasopressin receptor type-2 (V2R) is localized to cilia in kidney epithelial cells. Pharmacologic inhibition of V2R with tolvaptan increases ciliary length and mechanosensory function. Genetic knockdown of V2R, however, does not have any effect on ciliary length, although the effect of tolvaptan on ciliary length is dampened. Our study reveals that tolvaptan may have a cilia-specific …

Gamete Nuclear Migration In Animals And Plants, Umma Fatema, Mohammad F. Ali, Zheng Hu, Anthony J. Clark, Tomokazu Kawashima

Plant and Soil Sciences Faculty Publications

The migration of male and female gamete nuclei to each other in the fertilized egg is a prerequisite for the blending of genetic materials and the initiation of the next generation. Interestingly, many differences have been found in the mechanism of gamete nuclear movement among animals and plants. Female to male gamete nuclear movement in animals and brown algae relies on microtubules. By contrast, in flowering plants, the male gamete nucleus is carried to the female gamete nucleus by the filamentous actin cytoskeleton. As techniques have developed from light, electron, fluorescence, immunofluorescence, and confocal microscopy to live-cell time-lapse imaging using …

Amphiphilic Peptides For Efficient Sirna Delivery, Saghar Mozaffari, Emira Bousoik, Farideh Amirrad, Robert Lamboy, Melissa Coyle, Ryley Hall, Abdulaziz Alasmari, Parvin Mahdipoor, Keykavous Parang, Hamidreza Montazeri Aliabadi

Pharmacy Faculty Articles and Research

A number of amphiphilic cyclic peptides—[FR]4, [WR]5, and [WK]5—containing hydrophobic and positively-charged amino acids were synthesized by Fmoc/tBu solid-phase peptide methods and evaluated for their efficiency in intracellular delivery of siRNA to triple-negative breast cancer cell lines, MDA-MB-231 and MDA-MB-468, in the presence and absence of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). Among the peptides, [WR]5, which contains alternate tryptophan (W) and arginine (R) residues, was found to be the most efficient in the delivery of siRNA by improving the delivery by more than 3-fold when compared to other synthesized cyclic peptides that were not efficient. The data also showed that co-formulation of [WR]5 …

Mechanisms Of Oriented Cell Division And Their Roles In Tissue Development, Evan Blake Dewey

Biology ETDs

Properly executed cell division is crucial to development, maintenance, and longevity of multicellular organisms. Defects in both symmetric and asymmetric divisions can lead to improper developmental patterning, as well as genomic instability, disruption of tissue homeostasis, and cancer. Our research focuses on how regulators orchestrate proper cell divisions. Mushroom Body Defect (Mud) is one such regulator, and here we describe how Mud is regulated via the Hippo signaling pathway kinase Warts (Wts), showing Wts phosphorylates Mud to enhance interaction with the polarity protein Partner of Inscuteable, promoting spindle orientation activity. We next focus on another regulator, Shortstop (Shot), describing a …

Deletion Of Uls1 Confers Damage Tolerance In Sgs1 Mutants Through A Top3-Dependent D-Loop Mediated Fork Restart Pathway, M. Rebecca Glineburg, Eleanor Johns, F. Brad Johnson

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Homologous recombination (HR)-based repair during DNA replication can apparently utilize several partially overlapping repair pathways in response to any given lesion. A key player in HR repair is the Sgs1-Top3-Rmi1 (STR) complex, which is critical for resolving X-shaped recombination intermediates formed following bypass of methyl methanesulfonate (MMS)-induced damage. STR mutants are also sensitive to the ribonucleotide reductase inhibitor, hydroxyurea (HU), but unlike MMS treatment, HU treatment is not accompanied by X-structure accumulation, and it is thus unclear how STR functions in this context. Here we provide evidence that HU-induced fork stalling enlists Top3 prior to recombination intermediate formation. The resistance …