Cell Biology Commons^™

Architects Of Mrna Fate: Molecular And Cellular Control Of P-Body Organization In The Drosophilia Melanogaster Female Germline, Samantha Milano

Dissertations, Theses, and Capstone Projects

Processing bodies (P-bodies) are cytoplasmic ribonucleoprotein condensates that regulate mRNA storage, translational repression, and decay. While the biochemical principles governing condensate assembly have been extensively studied in vitro, how P-body organization is established and dynamically regulated in vivo to control specific mRNA populations remains poorly understood. This dissertation investigated the molecular and cellular mechanisms that govern P-body architecture and function in the Drosophila melanogaster female germline. First, I identified the conserved LSm protein Trailer Hitch (Tral) as a central organizer of P-body architecture. Using quantitative confocal and super-resolution microscopy combined with chemical perturbations, I showed that Tral coordinates the …

Effect Of Partial Ablation Of Skeletal Dynamin Related Protein 1 On Mitochondrial Health, Inflammation, And Fibrosis In A Mouse Model Of Duchenne Muscular Dystrophy, Tessa L. Duzz

Graduate Masters Theses

Duchenne muscular dystrophy (DMD) is a progressive neuromuscular disorder characterized by muscle weakness, degeneration, fibrosis, and impaired muscle regeneration. Mitochondrial dysfunction is an early pathological feature of DMD and has been linked to excessive mitochondrial fission. Dynamin-related protein 1 (Drp1) is a central regulator of mitochondrial fission, a key process in regulating mitochondrial quality and function. Inhibition of Drp1-mediated mitochondrial fission has shown promise as a potential therapeutic target for alleviating pathology and dysfunction in dystrophic muscle. The objective of this study was to determine whether partial skeletal muscle-specific ablation of Drp1 could improve muscle pathology and mitochondrial health in …

Oxidative Stress Mediated Glutamate Release And Nmda Receptor-Dependent Synaptic Remodeling In Radiation-Induced Cognitive Dysfunction, Thanh Lam

Dissertations and Theses (Open Access)

In children younger than 14 years old, the brain and other parts of the central nervous system are the most common sites for solid tumors. Radiotherapy is an effective treatment for central nervous system (CNS) tumors. However, it often causes a progressive decline in cognitive functions, which is especially devastating for pediatric patients. Although post-mitotic neurons are generally considered resistant to radiation-induced immediate cell death, ionizing radiation causes complex neurochemical and structural changes that damage synaptic integrity. In this study, we examined the molecular cascades following a 10 Gy radiation dose applied to mouse cortical neurons. We found that radiation-induced …

The Rpm-1/Phr Signaling Hub Modulates Tau-Induced Neurodegeneration Through Regulation Of Microtubule Stability And Mapk Pathways In C. Elegans, Xinxing Ding

Theses and Dissertations

Neurodegenerative diseases, including Alzheimer's disease and frontotemporal dementia, are characterized by the accumulation of pathological tau proteins and progressive neuronal loss. Although research regarding tau-mediated toxicity is extensive, the specific pathology that determine whether neurons maintain homeostasis or succumb to collapse under tau-induced stress remain incompletely elucidated. A central, yet still insufficiently understood, feature of these diseases is the disruption of the microtubule (MT) cytoskeleton . The PHR protein family is evolutionarily highly conserved; within this family, RPM-1 in C. elegans functions as an intracellular signaling hub that regulates axon development, synapse formation, axon termination, and various microtubule-associated processes. This …

A Computational Micropatterning Approach To Study Caveolae And Protein Localization In Vascular Biology, Andrew B. Grespin

Electronic Theses and Dissertations

Caveolae are specialized, flask-shaped membrane invaginations highly expressed in endothelium and dysregulated in atherosclerosis. Caveolae play a central role in buffering membrane tension, yet the principles governing their spatial organization remain elusive. Thus, we sought to generate the most comprehensive and systematic analysis of blood vessel caveolar spatial organization. However, cell culturing, the backbone of human-focused biological research, does not standardly do well to model physiologically relevant cell behaviors such as migration or polarity-based tissue formation, particularly for punctate proteins and structures like caveolae. Micropatterns are cell-adhesive shapes that biophysically confine cell(s) to a user defined geometry which stereotype organelle …

The Impact Of Tgfβ Conditioning And Socs3 Expression On Cytokine Signal Transduction And Inflammatory Gene Expression In Fibroblasts, Morgan Anderson-Crannage

NYMC Student Theses and Dissertations

Inflammation is a major driver in many aspects of recessive dystrophic epidermolysis bullosa (RDEB) pathology, including impaired wound healing, fibrosis, and potentially cutaneous squamous cell carcinoma development. Fibroblasts, as key stromal cells in the dermis, are responsible for orchestrating inflammatory responses through the secretion of cytokines and chemokines upon stimulation with IL-1α or IL-6. Suppressor of Cytokine Signaling 3 (SOCS3) functions as a negative feedback regulator of cytokine signaling and has emerged as a key modulator of inflammatory responses in immune cells and fibroblasts. Transforming Growth Factor Beta (TGFβ), a known driver of fibrosis in RDEB, has been implicated in …

In Vitro Reversal Of Abc Transporter Mediated Multidrug Resistance In Human Ovarian And Non-Small Cell Lung Cancer Models, Alison K. Kellom, Pia D. Vogel

Biological Sciences Theses and Dissertations

One of the major causes of treatment failure in aggressive cancers is multidrug resistance (MDR), which is linked to the overexpression of membrane efflux proteins that export chemotherapeutics from cancer cells. This mechanism prevents chemotherapeutic drugs from reaching cytotoxic concentrations intracellularly, allowing the cancer to survive. Two primary mediators of this mechanism are P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP). P-gp and BCRP are transmembrane ATP-binding cassette (ABC) transporters that are frequently overexpressed in MDR cancers. They utilize the binding and hydrolysis of ATP to transport a diverse range of amphipathic molecules of varying size (Schinkel and Jonker, 2003), …

Mllt1 Is Required To Maintain B-Lymphopoiesis, Janani Prakash

Dissertations

MLLT1 (also named ENL) is an epigenetic reader protein that binds to crotonylated or acetylated lysine residues of histone 3 through its N-terminal YEATS domain. Positive and negative regulatory complexes compete for binding to C-terminal MLLT1, and promote transcription elongation (SEC, Super elongation complex; DOT1L) or transcriptional repression (PRC1, Polycomb repressive complex 1). MLLT1 was initially identified as a chromosomal translocation partner to MLL(KMT2A) in a subset of MLL-rearranged leukemias. MLL-ENL fusion protein causes both lymphoid (predominantly B-ALL) and mixed lineage leukemias. MLLT1 has been implicated in leukemic stem cell survival in MLL-rearranged cell lines but its role in normal …

Potential Innate And Adaptive Roles Played By Γδ T Cells In A Bacterial Immunization Model, Lee Anne Talbot

Seton Hall University Dissertations and Theses (ETDs)

Francisella tularensis is a highly infectious intracellular bacterium and the causative agent of tularemia, with pulmonary infection resulting in severe disease and high mortality if untreated. While protective immunity to F. tularensis has been largely attributed to CD4⁺ T cell–mediated IFN-γ responses, the contribution of γδ T cells to mucosal immunity and vaccine-induced protection remains poorly defined. The objective of this study was to characterize the role of γδ T cells during primary pulmonary infection with F. tularensis live vaccine strain (LVS) and following intranasal immunization with inactivated F. tularensis (iFt) prior to LVS challenge.

Using a murine intranasal infection …

Junctional Actin As A Mechanical Hub For Supracellular Actomyosin Force Transmission During Apical Constriction, Jasneet Brar

UNLV Theses, Dissertations, Professional Papers, and Capstones

Apical constriction is a conserved morphogenetic mechanism that drives epithelial folding during development. During ventral furrow formation in Drosophila melanogaster, contractile actomyosin networks generate forces that reduce apical cell area resulting in tissue invagination. For these cell-scale forces to produce coordinated tissue-scale changes, contractile networks must be mechanically integrated across neighboring cells. Although adherens junctions are known to mediate this coupling, it is unclear how junctions are integrated into cortical actin cytoskeleton, which directly determines cell, and consequently tissue, shape. This thesis tests the hypothesis that supracellular actomyosin organization during apical constriction depends on distinct adherens junction based mechanical couplings: …

Thrombin-Induced Myofibroblast Differentiation Is Regulated By Myocardin And Novel Effector Genes In Ipf Fibroblasts, Christiana Okeke

Biotechnology Theses

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease characterized by fibroblast activation, excessive extracellular matrix (ECM) deposition, and irreversible respiratory decline. In this study, we investigated the role of myocardin and its downstream effectors, RGS5, DLGAP5, and TAGLN, in thrombin-induced myofibroblast differentiation and ECM remodeling using primary human IPF fibroblasts. Myocardin knockdown significantly attenuated thrombin-induced expression of profibrotic genes, including FN1, COL1A1, PAI-1, ACTA2, and CNN1, as well as the novel effectors RGS5, DLGAP5, and TAGLN, confirming myocardin as a central regulator of fibrotic signaling. Silencing RGS5 produced minimal effects on gene and protein expression despite minor downward …

Role Of Kif4a In The Fxa-Induced Phenotypic Modulation Of Pleural Mesothelial Cells, Sudishna Khanal

Biotechnology Theses

Pleural injuries can disrupt the organization of the pleural surface, leading to pleural remodeling and fibrosis (PF), characterized by the proliferation of myofibroblasts expressing alpha-smooth muscle actin (α-SMA) and the deposition of extracellular matrix proteins, primarily due to the mesenchymal transition of pleural mesothelial cells (PMCs) (MesoMT). It is well established that various external stimuli, such as TGF-β, thrombin, and factor Xa (FXa), induce MesoMT. Our laboratory found that myocardin, a transcriptional co-activator, was dramatically up-regulated during MesoMT, and that gene silencing of myocardin (MyoCD) diminished MesoMT. RNA sequencing data showed that FXa activated a set of genes not upregulated …

Bax Activation Through The N-Terminal Bh3-Like Domains Of Vdac1 And Vdac2, Autumn A. Peters

Honors Theses

Voltage-dependent anion channels (VDACs) are central to mitochondrial function by mediating metabolite diffusion across the mitochondrial outer membrane (MOM). Two isoforms­­­­­­­­­­­,­­­­­­­­­­­­­­­­­­­­­­­­­­­­ VDACs 1 and 2, are also implicated in apoptosis based on interactions with Bcl-2 family proteins that control this process, including Bax and Bcl-xL. Activation of the pro-apoptotic protein Bax by interaction with ‘BH3-only’ proteins, such as Bim or Bid, induces MOM permeabilization to signal apoptosis, yet accumulating evidence indicates VDACs 1 and 2 may also affect Bax. We discovered that the VDAC N-terminal domains contain high sequence similarity to the conserved BH3 domains within Bcl-2 family members that …

Identifying The Role Of Human Dna Polymerase Delta During Human Cytomegalovirus Genome Synthesis, Rachel Laree Dansereau

Dartmouth College Master’s Theses

Human cytomegalovirus (HCMV) is a large double stranded DNA virus and member of the Herpesviridae family. Like all herpesviruses, HCMV presents with characteristics of persistent, lifelong infections that transition between lytic and latent states. The replication of the viral genome is traditionally thought to occur by a rolling circle mechanism, but this model is supported by little evidence. It is known that HCMV actively recruits several host proteins to viral replication compartments (RCs), including proteins involved in the DNA damage response (DDR). The exact mechanisms of how these proteins are used and in what ways they help the virus remain …

Analysis Of Developmental Cardiogenic Processes Mediated By Fox And Zinc-Finger Transcription Factors, Rajnandani Katariya

All-Inclusive List of Electronic Theses and Dissertations

Cardiogenesis is a highly choreographed biological process requiring the precise integration of gene regulatory networks to govern cell division, fate determination, and spatial positioning. Disruptions in these mechanisms lead to congenital heart defects (CHDs), which affect approximately 1% of live births globally. Due to the evolutionary conservation of cardiac signaling pathways and the structural homologies between the Drosophila dorsal vessel and the early vertebrate heart tube, Drosophila melanogaster serves as a powerful model for dissecting the fundamental mechanisms of heart development. This dissertation investigates the molecular orchestration of cardiac development, specifically focusing on the roles of the transcription factors Jumu …

Reconstruction Of Fox Transcription Factor-Regulated Subnetworks Mediating Cardiac Progenitor Cell Divisions, Md Rezaul Hasan

All-Inclusive List of Electronic Theses and Dissertations

Congenital heart disease (CHD) is the most common congenital anomaly worldwide, affecting approximately 1% of live births, corresponding to 1.35 million infants born with CHD each year, and remains a leading cause of infant mortality; therefore, it is urgent to understand the genetic and molecular mechanisms underlying CHD for advancing early diagnosis and treatment. Because many aspects of the Drosophila heart formation are highly reminiscent of vertebrate heart development, Drosophila melanogaster serves as a simple yet powerful model system for studying cardiac development and CHD. While at least eight Forkhead box (Fox) transcription factors (TFs) are required for proper cardiac …

Analysis Of The Effects Of Astaxanthin On Human Colorectal Cancer Cells, Kara A. Walters

Theses/Capstones/Creative Projects

Astaxanthin (AXT) is an antioxidant carotenoid that is produced by the microalgae Haemococcus pluvialis. This supplement is best known for its potential health benefits including anti-inflammatory, antitumor, immunomodulatory, anticancer and antidiabetic activities. Astaxanthin is marketed as an oral dietary supplement and is widely used in the nutraceutical industry as well as a coloring agent in the food industry. Since Astaxanthin has been increasingly popular as a dietary supplement, cytotoxicity is relevant to consumer exposure. Obtaining the IC50, the concentration that inhibits 50% of cell growth, is important to find how Astaxanthin may interact with cancer, and this can be found …

Morphological Variation Of Lingual Glands In Wild American Alligator (Alligator Mississippiensis) Populations, Benjamin Angalet

Master's Theses

American alligators (Alligator mississippiensis) inhabit diverse aquatic ecosystems including freshwater wetlands, swamps, and estuarine rivers. As apex predators, their physiological resilience has implications for ecosystem stability and long-term conservation. With projected sea-level rise and increasing saltwater intrusion into coastal freshwater habitats, understanding the osmoregulatory capacity of alligators is increasingly important. Unlike marine-tolerant crocodilians such as the saltwater crocodile (Crocodylus porosus), which possess specialized salt-secreting lingual glands in addition to renal and cloacal mechanisms, the morphology and physiological significance of lingual glands in wild American alligators remain poorly understood. This study examined lingual gland morphology and plasma …

Genetic Screen For Regulators Of Pol4, A Dna Repair Polymerase In Saccharomyces Cerevisiae, Pasang Dolma Sherpa

Theses and Dissertations

In Saccharomyces cerevisiae, DNA polymerase 4 (POL4) is the beta repair polymerase, the product of the POL4 gene, and is involved in base excision repair (BER) and microhomology-mediated end joining (MMEJ). Despite its involvement in these repair pathways and its conservation across eukaryotes, deletion of POL4 shows no detectable phenotype under standard laboratory conditions. I hypothesized that unknown genes act as backup systems, providing redundant activities that allow pol4Δ cells to survive. To test this, a genetic screen for mutants showing synthetic lethality with pol4Δ was implemented. I constructed a strain lacking the POL4 gene and carrying …

The Impact Of Glucose Exposure On Organic Cation Transporters (Oct) Function In A Corneal Epithelial Cell Line, David A. Garza

Theses & Dissertations

Organic cation transporters (OCT) facilitate the movement of neurochemicals and medications, contribute to the removal of cellular waste, and facilitate neuronal communication. Three subtypes of these high-capacity, low-affinity transporters (OCT1, OCT2, and OCT3) are differently expressed in peripheral tissues such as the liver, kidneys, as well as the central nervous system. OCTs are also expressed in ocular tissues. Chronic hyperglycemia is a complication commonly associated with diabetes that can lead to ocular diseases such as diabetic keratopathy, which affects the cornea. In this project, we expose immortalized human corneal epithelial cells (HCE-S) to various glucose concentrations to study their impact …

Effects Of M6a Dna Methylation By Bacterial Methyltransferase In Colorectal Cancer, Fabian Alejandro Mendoza Galvan

Dissertations and Theses (Open Access)

Effects of m6A DNA methylation by bacterial methyltransferase in colorectal cancer Fabian Alejandro Mendoza Galvan Advisory Professor: Angela H. Ting, Ph.D. Fusobacterium nucleatum animalis (Fna) is found in the human oral cavity and gut. A distinct clade of Fna is primarily enriched in the tumor microenvironment (TME) and within colorectal cancer (CRC) cells. This clade DNA methylation pattern is primarily catalyzed by a cell-cycle regulated methyltransferase (CcrM) ortholog, M.FnI, that targets the GANTC sequence motif through methyl-6-Adenine (m6A) DNA methylation. We hypothesized that M.FnI enzyme can induce m6A methylation abnormalities in CRC cells to promote cancer progression. Evidence for endogenous …

From Antigen Presentation To Tumor Control: Mechanisms Of Type I Conventional Dendritic Cell-Based Cancer Vaccines, Josue E. Pineda

Dissertations and Theses (Open Access)

Type 1 conventional dendritic cells (cDC1s) are important for generating and sustaining antitumor immunity. Accordingly, the abundance of cDC1s in human tumors correlates with improved outcomes in cancer. Capitalizing on this role, we previously demonstrated that vaccination with in vitro-derived murine cDC1s elicits durable tumor control in multiple preclinical models; however, the immunological mechanisms underlying the efficacy of cDC1 vaccination remain unclear. Here, we examined whether in vitro-derived cDC1s resemble tumor-infiltrating DC populations and whether MHC-I and MHC-II antigen presentation contribute to cDC1-mediated tumor control following vaccination in melanoma.

As expected, MHC-I- or MHC-II-deficiency had minimal impact on …

Abnormal Trafficking And Processing Of Multiple Matrix Metalloproteinases Drive Cartilage Defects In Congenital Disorders Of Glycosylation, Chia-Lun Wu

All Dissertations

Congenital Disorders of Glycosylation (CDG) are rare metabolic diseases caused by defects in glycosylation. Despite identification of over 200 CDG types, the mechanisms linking glycosylation defects to diverse clinical phenotypes remain unclear. This dissertation uses zebrafish models of PMM2-CDG and STT3-CDG to redefine CDG pathogenesis, shifting from a simple glycan deficiency model to one involving disrupted cellular spatial organization.

We identify a protease-dependent pathway underlying craniofacial cartilage defects. Specifically, defective proteolytic processing of N-cadherin, a key adhesion molecule in chondrogenesis, is a central driver of pathology. We further uncover an unconventional trafficking mechanism in which ER stress and altered secretory …

Using The Flexon Approach To Rnai To Identify Essential Genes That Affect Gonadal Development In C. Elegans, Joyce S. Lefevers

Undergraduate Theses

To elucidate the molecular role of essential genes in the gonadal development of Caenorhabditis elegans (C. elegans) it is necessary to utilize specialized molecular techniques such that the phenotypic effects of gene knockdown can be studied while the viability of the organism is preserved. Shaffer and Greenwald (2022) developed the floxed exon (flexon), a tool that improves upon previous approaches to spatiotemporal control of gene expression. The flexon subunit is made up of an artificial exon with a stop cassette flanked by artificial introns which, when inserted into a gene of interest, prevents the expression of that gene. …

Quantification Of Mouse Tracheal Epithelial Cell Differentiation With Cilia Defects, Olivia V. Allen

Honors Thesis

Primary Ciliary Dyskinesia (PCD) is an autosomal recessive disorder that affects 1 in every 7,500 live births. PCD results from motile cilia defects, impairing mucociliary clearance and causing chronic respiratory infections. Our lab studies include three PCD mouse lines — bgh (Spef2), nm1054 (Cfap221), and Cfap54^gt/gt (Cfap54). Prior transcriptomic data led us to hypothesize that PCD mutant mouse tracheal epithelial cells (MTECs) exhibit reduced differentiation into ciliated cells. MTECs from the trachea of the Wild Type (WT) and the PCD mutant mouse lines were cultured at an Air Liquid Interface (ALI) to start …

Targeting Rna Polymerase I In Ewing Sarcoma Treatment, Alexis Bruce

Theses

Ewing sarcoma is a rare and aggressive pediatric bone cancer with poor survival rates in patients, as low as 30% in advanced or recurrent cases. There are limited treatment options, making molecularly targeted therapy vital to explore. Through CRISPR scans of Ewing sarcoma cell lines, ribosome biogenesis was highlighted as a potential target. As RNA polymerase I is a key component of ribosome biogenesis, the cytotoxic ability of two RNA Polymerase I inhibitors, CX-5461 and BMH-21, were used on patient-derived Ewing sarcoma cells. The efficacy of the drugs on two cell lines was determined via measuring cell viability, migration potential, …

Cellular And Molecular Characterization Of Ube3a Function In Cic-Dux4 Sarcoma, Jesse D. Walker

Theses

CIC-DUX4 sarcoma (CDS) is a rare and extremely aggressive soft tissue sarcoma that primarily affects children and young adults. CDS is characterized by an oncogenic chromosomal translocation. Current treatments for CDS are similar to those in other sarcomas like surgery, chemotherapy, and radiation. Treatments, however show that CDS responds poorly compared to other sarcomas, due to relapses of localized disease at high rates and short duration response of treatment, proving the importance of understanding CIC-DUX4’s complex role on how it regulates overall gene expression in CDS cells from a molecular approach.

UBE3A is a ubiquitin protein ligase that plays a …

Differential Effects Of Veratridine And 5-Fluorouracil On Ubxn2a-Targeted Mortalin And Rictor Proteins In Patient-Derived Colorectal Cancer Cells, Kate S. Schraufnagel

Honors Thesis

Colorectal cancer (CRC) is a leading cause of cancer-related mortality, particularly in patients with metastatic CRC and/or those who have developed resistance to conventional chemotherapy. There has been a significant rise in early-onset CRC (EOCRC) incidences in patients under age 50. Due to lack of screening, these patients are commonly diagnosed in the later stages where there is a lack of effective therapies. This highlights the need for targeted therapies that address the molecular drivers of tumor progression and treatment resistance. UBXN2A is a tumor suppressor protein that regulates key oncogenic pathways in CRC, including Mortalin-2 (mot-2)-mediated p53 suppression and …

Cell-Free Mitochondrial Dna (Mtdna) Triggers Vascular Dysfunction Via Toll-Like Receptor 9 (Tlr9)-Dependent Activation Of Inflammasomes, Mohin Amin

Senior Theses

Hypertension is the leading global risk factor for mortality and is closely associated with vascular inflammation and dysfunction. Damaged mitochondria release cell-free mitochondrial DNA (cf-mtDNA), which activates toll-like receptor 9 (TLR9). The binding of TLR9 to mtDNA activates the NLRP3 inflammasome pathway, promoting the release of pro-inflammatory cytokines via gasdermin D (GSDMD), therefore worsening inflammation. However, the mechanisms linking mitochondrial injury to inflammation-induced vascular dysfunction remain unclear. We hypothesize that cf-mtDNA triggers TLR9-dependent NLRP3 inflammasome activation contributing to vascular and endothelial dysfunction. To assess that, adult male C57BL/6 were exposed to 28 consecutive days of chronic unpredictable stress (CUS) or …

Mitochondria Dynamics In Microglia During Health, Inflammation, And Aging, Alicia Nicole Pietramale

Dartmouth College Ph.D Dissertations

Microglia continually surveil the brain, allowing for rapid detection of tissue damage or infection. Microglial metabolism is linked to tissue homeostasis, yet how mitochondria are subcellularly partitioned in microglia and dynamically reorganize during surveillance, injury responses, and phagocytic engulfment in the intact brain has remained unclear. In this dissertation, I combine intravital imaging, ultrastructural analyses, and metabolic and cytoskeletal markers to investigate how mitochondrial organization relates to microglial function across health, inflammation, and aging.

I first show that microglial processes diverge in their mitochondrial content, with some containing multiple mitochondria while others are completely void. This heterogeneous partitioning is conserved …