Cell Biology Commons^™

Investigating The Effects Of Cell Signaling Mutants And Inhibitors On Chemokinesis In Dictyostelium Discoideum., James Rybczyk

Honors Scholar Theses

Chemokinesis is the augmentation of cellular motility in response to chemical stimuli. While it is known that chemical factors induce changes in the behavior of a cell with regards to motility, the mechanism by which this process occurs is poorly understood. The aim of this project is to identify potential proteins within the signaling pathways that integrate the message brought on by chemical ligands and consequently lead to changes in cellular motility. In order to accomplish this goal, various gene knockout mutants of the amoeboid species Dictyostelium discoideum are compared to an axenic wild-type strain (AX2) based on their relative …

The Effect Of Fibrodysplasia Ossificans Progressiva On The Tongue, Amy Backal, Amanda Harrop, David J. Goldhamer Dr.

Honors Scholar Theses

FOP is a rare genetic disorder in which skeletal muscle and associated connective tissue progressively turn to bone through a process called heterotopic ossification (HO). The extra skeletal bone growth is cumulative, eventually trapping patients in a second skeleton that eventually leads to death by asphyxiation. The FOP mutation is autosomal dominant that can be inherited or acquired sporadically. Unfortunately, FOP is currently incurable with no therapeutic options to inhibit bone growth or reduce existing bone nodules. My project intends to further our understanding of the cellular mechanisms of the disease within the tongue muscle. A population of cells known …

The Regulation Of Chemokinesis By The Soil Amoeba, Dictyostelium Discoideum, Julia Horan

Honors Scholar Theses

Many types of cells crawl on solid surfaces by amoeboid locomotion. Membrane protrusions, such as pseudopods, are generated by outward directed forces and the cell body retracts to allow the cell to migrate on the surface. The movement can be random, or can be directional in response to diffusible (chemotaxis) or surface associated signals (haptotaxis). It has been known for some time that chemotactic signals also lead to an increase in overall cell speed (chemokinesis), however the mechanism of this speed increase is unknown. This project investigates the cellular signaling pathways involved in the regulation of cell speed by ligands …

Identifying The Cell Composition And Clonal Diversity Of Supratentorial Ependymoma Using Single Cell Rna-Sequencing, James He

Honors Scholar Theses

Ependymoma is a primary solid tumor of the central nervous system. Supratentorial ependymoma (ST-EPN), a subtype of ependymomas, is driven by an oncogenic fusion between the ZFTA and RELA genes in 70% of cases. We introduced this fusion into neural progenitor cells of mice embryos via in utero electroporation of a non-viral binary piggyBac transposon system containing ZFTA-RELA. From preliminary data in the LoTurco lab, inducing the expression of ZFTA-RELA into different neural progenitor cells produces tumors of varying lethality and cellular composition. To define the cellular composition and subclonal diversity of ST-EPN tumors, we used single cell RNA-sequencing …

The Effects Of Mapk Signaling On The Development Of Cerebellar Granule Cells, Kerry Morgan

Honors Scholar Theses

The granule cells are the most abundant neuronal type in the human brain. Rapid proliferation of granule cell progenitors results in dramatic expansion and folding of the cerebellar cortex during postnatal development. Mis-regulation of this proliferation process causes medulloblastoma, the most prevalent childhood brain tumor. In the developing cerebellum, granule cells are derived from Atoh1-expressing cells, which arise from the upper rhombic lip (the interface between the roof plate and neuroepithelium). In addition to granule cells, the Atoh1 lineage also gives rise to different types of neurons including cerebellar nuclei neurons. In the current study, I have investigated the …

Single-Fluorophore Sensors For Mechanical Force In Living Cells, Sarah Kricheff

Honors Scholar Theses

Mechanotransduction is the process by which a mechanical stimulus is converted to a cellular signal. This process is heavily influential of cell morphology, differentiation, and behavior. However, altered levels of mechanical stimuli are also found in many pathological contexts. For example, cancerous cells have stiffer surrounding tissue than healthy cells, and research suggests that this alters cell behavior and promotes metastasis. Despite these findings, the cellular processes behind these signaling alterations remain widely unknown. Understanding these cascades is critical, as involved proteins can give us a deeper understanding of the role of mechanotransduction, and certain proteins can potentially be targeted …

The Anti-Proliferative Effects Of Methotrexate And Novel Ucp1162 On Acute Myeloid Leukemia Cell Lines, Jacqueline Klepinger, Charles Giardina, Didem Ozcan

Honors Scholar Theses

Cancer cells proliferate at rapid rates due to the aberrant activity of proteins involved in regulating the cell cycle. This characteristic allows mutated cancer cells to spread and metastasize, causing lesions to form throughout the body. Two treatment conditions, one classical antifolate methotrexate (MTX) and non-classical, novel antifolate UCP1162, were tested on a panel of acute myeloid leukemia (AML) cell lines to determine if UCP1162 has higher anti-proliferative activity. High dose MTX is used as a first line chemotherapy in common childhood malignancies such as acute lymphoid leukemia (ALL). Methotrexate is excluded from acute myeloid leukemia (AML) treatments based on …

Microglia-Neuron Interactions In A Mouse Model Of Low Grade Neuroepithelial Tumors, Veolette Hanna

Honors Scholar Theses

Microglia are the macrophages of the brain and spinal cord, playing an important role in the immune response to disease states of the nervous system. This study conducts an investigation on the activity of microglia in response to low grade neuroepithelial tumors. Using mouse models and microglial markers, a qualitative and quantitative analysis of microglia activation, migration, and invasion within the brain cortex during early stages of tumor development was conducted. It was found that the presence of a low grade neuroepithelial tumor in the cortex of one hemisphere of the brain causes significant microglia activation in comparison to the …

Characterization Of A Mycoplasma Pneumoniae Cards Toxin Mutant, Nikaash Pasnoori

Honors Scholar Theses

Mycoplasma pneumoniae is a high-burden pathogen which causes mild to significant infections of the respiratory system. According to the CDC, an estimated two million cases occur yearly in the United States alone, demonstrating the widespread effect of the pathogen. In addition to being the cause of respiratory infections, M. pneumoniae has also been implicated in exacerbating pre-existing asthma conditions. These morbidities make finding a vaccine candidate a vital part of easing the healthcare burden caused by the pathogen. The current mechanism of infection is unknown, but recent evidence points to the Community Acquired Respiratory Distress Syndrome (CARDS) toxin as being …

An Analysis Of Crispr-Cas Gene Editing In Agriculture, Ashley Laliberte

Honors Scholar Theses

The CRISPR-Cas system is a promising form of gene editing, especially for the agriculture industry. The ability to make single-nucleotide edits within a gene of interest, without the need to introduce foreign DNA, is a powerful tool for designing healthier and more efficient crops and food animals. This system provides opportunity for increased nutritional value, decreased food waste, and more economically and environmentally sustainable food production. Though this biotechnology is facing mechanistic limitations due to off-target effects and inefficient homology-directed repair, vast improvements have already been made to improve its efficacy. The CRISPR-Cas system is already the most advanced form …

Development Of A Sonically Powered Biodegradable Nanogenerator For Bone Regeneration, Avi Patel

Honors Scholar Theses

Background: Reconstruction of bone fractures and defects remains a big challenge in orthopedic surgery. While regenerative engineering has advanced the field greatly using a combination of biomaterial scaffolds and stem cells, one matter of difficulty is inducing osteogenesis in these cells. Recent works have shown electricity’s ability to promote osteogenesis in stem cell lines when seeded in bone scaffolds; however, typical electrical stimulators are either (a) externally housed and require overcomplex percutaneous wires be connected to the implanted scaffold or (b) implanted non-degradable devices which contain toxic batteries and require invasive removal surgeries.

Objective: Here, we establish a biodegradable, piezoelectric …

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 …

Modeling And Analyzing An Optogenetic System For Photoactivatable Protein Dissociation, Anvin Thomas, James Schaff

Honors Scholar Theses

Computational modeling of cell-cell interactions can grant clues and can answer questions about an experiment, especially for observations about binding interactions and kinetics. This approach was used to investigate an interaction between a light-oxygen-voltage (LOV) domain and an engineered protein called Zdark (Zdk). The LOV domain is membrane-bound while Zdk is cytosolic. The LOV domain and Zdk bind strongly in dark (K_d 26.2 nM), and weakly upon exposure to blue light (K_d > 4 μM). Total internal reflection fluorescence (TIRF) images are acquired of Zdk, the fluorescent species bound to a mCherry tag, and the loss of fluorescence is …

Effect Of Silk-Based Hydrogel Topography On Intestinal Epithelial Cell Morphology And Wound Healing In Vitro, Marisa E. Boch

Honors Scholar Theses

Recent advances in the field of biomaterials have suggested that cells cultured on substrates resembling the native tissue mechanical properties, matrix and growth factor composition, and topography can adopt phenotypes that more closely resemble the in vivo tissue compared to cells cultured on non-mimetic constructs. Understanding the effect of culture substrate on in vitro tissue formation is important for bioengineering applications that include mechanistic studies of healthy tissue function and development of disease models. In this work, Caco-2 adenocarcinoma cells were seeded on flat and crypt-like topographies of 3D-printed cytocompatible hydrogels derived from silk fibroin protein. Silk hydrogels were selected …

Effects Of Piggybac Transposable Element Derived 5 (Pgbd5) In Cortical Tissue, Benjamin Shao

Honors Scholar Theses

Many cancers are known to have genetic rearrangements, as these rearrangements develop abnormalities that can lead to certain types of cancer. Many of these genetic rearrangements can be caused by transposons, which are DNA sequences that can change its position and move to other positions within the genome. Transposons move to and integrate into a new location by the action of transposase enzymes, and recently genes that code for proteins similar to transposases and with transposase activity have been identified in the human and other vertebrate genomes. In this study, one of these genes, human piggyBac transposable element derived 5 …

Identifying New Genes Involved In Centromere Establishment, Megan Boyer

Honors Scholar Theses

The centromere is a site on the chromosome that mediates accurate cell division by serving as a platform for kinetochore assembly, and microtubule attachment during cell division. Errors in the process of chromosome segregation can contribute to genetic irregularities, such as those seen in cancer and congenital defects. Our lab uses the ectopic centromere as a tool to discover what proteins may be involved in centromere establishment, defined as the deposition of CENP-A at the locus. We use the lacO/LacI system within Drosophila S2 cells that contain a CAL1-GFP- LacI transgene and an integrated lacO array to study the ectopic …

Reconstitution Of Gabaergic Postsynapses In Host Cells, Karthik Kanamalla

Honors Scholar Theses

Type A GABA receptors (GABAARs) can be found embedded in postsynaptic membranes or in a variety of extrasynaptic locations. Receptors with synaptic function are recruited to the postsynapse by submembranous scaffolds composed of gephyrin and collybistin (CB). This study was aimed at assessing whether the ability to interact with the scaffold differentiates synaptic from non-synaptic receptors. Using HEK293 cells as an expression system, and indirect immunofluorescence (IF), co-localization of extrasynaptic receptors α1β3δ and α4β3δ with the CB-gephyrin scaffold was assessed and compared with that of the synaptic receptor α1β3γ2. Results indicated that both extrasynaptic receptors were able to colocalize with …

Programming Heart Disease: Does Poor Maternal Nutrition Alter Expression Of Cardiac Markers Of Proliferation, Hypertrophy, And Fibrosis In Offspring?, Cathy Chun

Honors Scholar Theses

Maternal malnutrition can affect fetal organogenesis, metabolic processes, and factors involved in developmental regulation. Of the many physiological effects poor maternal nutrition can induce in offspring, one of the most important organs affected is the heart. Cardiovascular disease has been associated with poor maternal diet. It also been suggested that hypertension can originate during impaired intrauterine growth and development. Hypertension can trigger hypertensive heart disease and is associated with numerous heart complications. We hypothesized that poor maternal nutrition would alter critical growth factors associated with normal heart development, specifically, insulin-like growth factor (IGF)-1, IGF-2, transforming growth factor (TGF)β, and connective …

The Development Of Skeletal Muscle In Young Horses: An Ultrasonography And Satellite Cell Approach, Emma K. Lavigne

Honors Scholar Theses

Muscle growth in young horses is characterized by an increase in muscle cross-sectional area, which can be accomplished through the activation and differentiation of satellite cells. Satellite cells can be stimulated or inhibited in response to different cytokines and growth factors and are key mediators of muscle hypertrophy and regeneration. The aim of this study was to investigate the growth of the longissimus dorsi (LD) muscle in horses under 5 years of age and to obtain preliminary data on satellite cell behavior in foals. The area, width, height, and subcutaneous fat were measured using ultrasonography at 6-month increments over the …

Post-Injury Calcium Chelation Rescues Skeletal Muscle Regeneration In Mice, Matthew D. Magda

Honors Scholar Theses

During aging the ability of skeletal muscle to regenerate after injury wanes until muscle integrity cannot be maintained. In this study it is shown that calcium chelation can restore young-like regenerative ability in an aged mouse model of skeletal muscle regeneration.

Dikar-Induced Synthetic Lethality In A Drosophila Model Of Cag Repeat Diseases Does Not Result From An Expression Feedback Loop, Daniel Camacho

Honors Scholar Theses

Human CAG repeat diseases manifest themselves through the common pathology of neurodeneration. This pathological link is attributed to the property shared by all nine of these diseases: an expanded polyglutamine (polyQ) tract. The most evident result of polyQ expansion is protein aggregation, and it is believed that this phenomenon is partly responsible for conferring cytotoxic properties on the mutated protein. Apart from sequestering the mutated protein, cellular aggregates are able to incorporate native proteins via polyQ-mediated aggregation, thus disrupting important cellular pathways. Using Drosophila melanogaster as a disease model, researchers have been able to compile collections of these so-called disease …

Investigations In Enhancing The Reproducibility Of Implantable Amperometric Glucose Biosensors For Mass Production, Dipesh Manharbhai Patel

Honors Scholar Theses

Implantable glucose sensors for Diabetes management should possess several attributes such as linearity, sensitivity, selectivity, long life time and should elicit no negative tissue response. Based on this, the UConn implantable glucose sensor team has developed a 5-layer sensor architecture that simultaneously affords the aforementioned requirements. However, the large scale production of these 5-layer sensors is inhibited by the lack of high sensor-to-sensor reproducibility. Herein, we investigate the origin of sensor-to-sensor irreproducibility and develop methodologies for large-scale fabrication of these devices.

Characterizing The Role Of Cortactin In Actin Pedestal Assembly By Enterohemorrhagic Escherichia Coli (Ehec), Sarah E. Grout

Honors Scholar Theses

Enterohemorrhagic Escherichia coli (EHEC) is a major foodborne cause of bloody diarrhea and renal failure. During colonization of the intestine, EHEC injects the transmembrane receptor protein Tir and the cytoplasmic effector protein EspFU into host cells to reorganize the actin cytoskeleton into adhesion “pedestals.” EspFU has been shown to bind and activate the actin nucleation factor N-WASP to drive actin polymerization into pedestals. However, EspFU can still assemble pedestals in cells lacking N-WASP, suggesting that this effector protein is able to also trigger N-WASP-independent pathways of actin polymerization during infection. Cortactin is an atypical nucleation factor that localizes to pedestals, …

Elucidating The Mechanism Of Antimigratory Activity Of Cardiac Glycosides, Joshua H. Johnson

Honors Scholar Theses

The focus of this research is on cell migration and how it can be better understood through the use of small molecules that modulate cell migratory activity. The results have particular relevance in the realm of cancer pharmacology. Cardiac glycosides, which are known inhibitors of the eukaryotic Na⁺/K⁺-ATPase, have been determined to have antimigratory activities through the screening of several small molecule libraries. Here we investigate the antimigratory activities of the cardiac glycoside digitoxin as well as its analogs that we synthesized. Antimigratory activity was determined by conducting a wound closure assay with MDA-MB-231 human breast …

Identifying Progenitor Cells Of Heterotopic Ossification, Eileen E. Semancik

Honors Scholar Theses

Heterotopic Ossification (HO) is the abnormal formation of bone within extraskeletal soft tissues. The condition can occur through both genetic and acquired means. Acquired cases of HO result from invasive surgery or traumatic injuries, with increasing prevalence of ectopic skeletogenesis as a result of combat-related blast injuries. HO has been characterized to some extent, including the histological features and the mutation underlying the genetic form, but the cells resident in skeletal muscle that represent the progenitors of heterotopic bone have yet to be determined. Only a few publications have attempted to definitively determine the progenitor cells in this disorder. Findings …

Improvements To The Forensic Analysis Of Mitochondrial Dna Typing, Elizabeth Montano

Honors Scholar Theses

Sequence analysis of human mitochondrial DNA (mtDNA) is an effective and reliable tool for the genetic characterization of forensic samples. The nature of the mitochondrial genome (mtgenome), its high copy number and small size (~17kb) makes it more resistant to degradation and more stable than nuclear DNA. For this reason mitochondrial DNA is often the only feasible option for the forensic analysis of environmentally compromised samples. Currently the forensic analysis of the mtgenome is restricted to the hypervariable regions, also known as the Displacement loop (d-loop). Previous studies, confirmed in the Strausbaugh lab, have demonstrated an increased variability in the …

Metallothionein Gene Dose And The Immune Response, Meaghan Roy-O-Reilly

Honors Scholar Theses

Metallothionein (MT) is a small, cysteine-rich protein with significant immunomodulatory activity. It has been shown to play a critical role in important cellular mechanisms including heavy metal detoxification, essential metal management and the inflammatory response. MT production can be induced by a number of cellular stressors and acts to lessen the harmful effects of oxidizing agents and heavy metal exposure. Previous studies have shown that the dose of the metallothionein gene present in an individual may have significant effects on the adaptive immune response, yet the mechanism behind this phenomenon remains unknown. We hypothesize that the gene dose of metallothionein …

Characterization Of Arginine-82 Mutants With Non-Native Chromophores, Vivek Alaigh

Honors Scholar Theses

Bacteriorhodopsin, found in most halobacteria, is an integral protein that contains seven transmembrane alpha helices and an organic chromophore, all-trans retinal. Light energy is captured by the protein and results in a series of spectrally discrete intermediates that conclude with a proton being pumped across the membrane from the cytoplasmic side to the extracellular milieu. The most blue-shifted photo-intermediate, the M state, has been of interest for protein-based holographic memory storage devices. Bacteriorhodopsin mutants were prepared with either a 4-hydroxy retinal or 3,4-dihydro retinal analog: R82A, R82C, R82H, R82K, R82N and R82Q. The objective of this research was to investigate …

Modeling Human Immune Response To The Lyme Disease-Causing Bacteria, Yevhen Rutovytskyy

Honors Scholar Theses

The purpose of this project is to develop and analyze a mathematical model for the pathogen-host interaction that occurs during early Lyme disease.

Based on the known biophysics of motility of Borrelia burgdorferi and a simple model for the immune response, a PDE model was created which tracks the time evolution of the concentrations of bacteria and activated immune cells in the dermis. We assume that a tick bite inoculates a highly localized population of bacteria into the dermis. These bacteria can multiply and migrate. The diffusive nature of the migration is assumed and modeled using the heat equation. Bacteria …