Cell Biology Commons^™

Focal Adhesion Genes And Proteins Are Differentially Expressed Across Cell Types In Down Syndrome, Brian Yoon

Senior Theses

Down syndrome (DS), caused by an extra copy of chromosome 21, leads to widespread gene expression changes through mechanisms such as transcriptional dysregulation and altered protein interactions. These disruptions contribute to a range of clinical features, including impaired wound healing, immune dysfunction, and neurodevelopmental abnormalities. This study focused on how DS affects fibroblast morphology and motility—processes critical for tissue repair and brain development. Using quantitative immunocytochemistry and image analysis, we found that DS fibroblasts displayed a broader, less polarized shape, with increased cell perimeter and reduced aspect ratio. However, levels of key adhesion proteins like vinculin, FAK, and β-actin were …

Cdh-3/Cadherin, Yap-1/Yap And Egl-44/Tead Promote Syx-2/Syntaxin And Eff-1 Fusogen-Mediated Phagosome Closure, Alec Whited, Aladin Elkhalil, Ginger Clark, Piya Ghose

Biology Theses - Archive

Physical interactions between cells, such as cell-cell junctions, can profoundly impact cell fate. A vital cell fate for normal development and homeostasis is programmed cell death. Cells fated to die must be efficiently cleared away via phagocytosis, and defects are associated with a variety of diseased states. Whether cell-cell physical associations affect programmed cell elimination has not been well-explored. Here we describe, in vivo, a cell-cell adhesion-driven signaling pathway that ensures compartment-specific cell clearance during development. We previously described the specialized cell death program “Compartmentalized Cell Elimination” (CCE) in the C. elegans embryo. During CCE, the tail-spike cell (TSC), a …

Genetic Analysis Of Methionine Restriction-Associated Mitochondrial Unfolded Protein Response Signaling., Josh D. Dodge

Biology Dissertations - Archive

The lifespan of an organism is dictated by various genetic and environmental factors. One such determinant is the health of mitochondria which are organelles that mediate various critical cell functions including a significant role in generating the vast supply of cellular energy. Indeed, the gradual decline of mitochondrial function is believed to be a hallmark and possible cause of aging. Paradoxically, mild mitochondrial dysfunction early in life extends lifespan in various model organisms. Cells use diverse approaches to promote mitochondrial homeostasis, including the transcriptional reprogramming of cells by mitochondrial unfolded protein response (UPRmt) to mitigate mitochondrial stress. Consistently, UPRmt activation …

Cell Competition Eliminates Aneuploid Human Pluripotent Stem Cells, Amanda I. Ya

Dartmouth College Ph.D Dissertations

Aberrant mitotic chromosome segregation results in the generation of cells with aneuploidy, an incorrect number of chromosomes. Aneuploidy can compromise the viability of the developing embryo and is the leading cause of pregnancy loss, failed embryo implantation, and congenital birth defects. Yet, widescale analysis of human embryos from in vitro fertilization (IVF) clinics suggests that aneuploidy is common, with upwards of 70% of preimplantation embryos being aneuploid.

Mitotic chromosome missegregation during post-zygotic development results in mosaic embryos made up of both diploid and aneuploid cells. Strikingly, upon transplant for pregnancy, mosaic embryos have been reported to result in healthy birth …

Temporal Dynamics Of Programmed Genome Rearrangement In Sea Lamprey Embryogenesis: A Deep Learning & Lightsheet Imaging Approach To Studying Early Developmental Transitions, Kasturi Rajandran

Theses and Dissertations--Biology

Programmed genome rearrangement (PGR) in the sea lamprey (Petromyzon marinus) leads to the elimination of ~0.5Gb (20%) of the germline genome during early embryogenesis, yet its timing relative to the maternal-to-zygotic transition (MZT) remains unclear. In this study, we imaged embryos cleared at 3-hour intervals (up to 72 hours post fertilization (hpf)) using high-resolution lightsheet fluorescence microscopy and a custom deep-learning image-analysis pipeline (~80% accuracy) to quantify nuclei and micronuclei counts. Micronuclei, which are the hallmarks of PGR first appear between 24 to 27hpf (vs ~36hpf previously reported) indicating PGR starts earlier than previously reported in the sea …

Elucidating The Effects Of Environmental And Physiological Conditions On Stem Cell Regulation In Vivo, Nimmy John

Electronic Theses & Dissertations (2024 - present)

The Notch signaling pathway is a highly conserved intercellular signaling pathway that any dysregulation can lead to a variety of human diseases. These diseases are further exacerbated by various environmental, pathological and genetic conditions. Previous studies have shown that these conditions have been known to affect the Notch transcriptional response. However, the molecular mechanisms by which such conditions influence Notch signaling remained largely unknown. Moreover, most Notch studies have relied on in vitro systems and indirect reporters, which can miss the dynamic and contextual nature of Notch signaling. Here, we systematically analyzed the effects of these conditions with single molecule …

Investigating The Role And Expression Of Aquaporin 10 Paralogs In Spiny Dogfish (Squalus Acanthias), Esosa Omoregie

College of Graduate Studies: Theses & Dissertations

Aquaporins (AQPs) are integral membrane proteins that facilitate the selective transport of water and small solutes across cell membranes, playing essential roles in maintaining osmotic balance in vertebrates. Among them, aquaglyceroporins such as AQP10 are capable of transporting water, glycerol, and urea, contributing to osmoregulatory and metabolic processes. This study investigated the expression, localization, and potential physiological roles of two AQP10 paralogs, AQP10C1 and AQP10C2, in the spiny dogfish (Squalus acanthias), a marine elasmobranch that maintains osmotic equilibrium through urea retention and ion regulation. Using RT-PCR, quantitative PCR, Western blotting and immunohistochemistry the study identified tissue-specific expression patterns of …

Unveiling The Cell Composition Of The Olfactory Migratory Mass: Perspectives On Terminal Nerve Formation, Olfactory Development, And Migration Of The Gnrh-1 Neurons, Enrico Amato Jr.

Electronic Theses & Dissertations (2024 - present)

Puberty is a postnatal developmental process required to initiate key sexual maturation events that are necessary for the propagation of species. Signals to initiate these events first begin with the Gonadotropin releasing hormone-1 (GnRH-1) neurons within the hypothalamus. The hormone GnRH-1 released by these neurons is crucial for puberty, fertility and reproductive processes by establishing the hypothalamic-pituitary-gonadal (HPG) axis, regulating release of sex hormones (Progesterone, Estrogen, Testosterone). Conditions related to inability of the GnRH-1 neurons to correctly release GnRH-1 can lead to aberrant or delayed puberty, a condition known as hypogonadotropic hypogonadism (HH). Interestingly, some patients with the hormonal disorder …

Glutamate Receptors At The Zebrafish Neuromuscular Junction, Trenton Randall

Honors College Theses

Glutamate is the main excitatory neurotransmitter in the CNS, but at the neuromuscular junction, that role is taken by acetylcholine. However, during embryonic development, non-cholinergic receptors, including those for glutamate, are also present at the NMJ, which are not maintained unless used. These receptors can still form functional circuits, as evidenced by a process called neurotransmitter respecification, in which a neuron changes which neurotransmitter it releases, and is accompanied by the upregulation of the corresponding receptor by the muscle. This process has been observed in frogs and in rats. We predict that zebrafish also exhibit this neurotransmitter plasticity. To assess …

The Role Of Eor-1/Plzf In Promoting Soma Compartment Specific Death In A Non-Canonical Cell Death Program In C. Elegans, Nathan Rather

2024 Fall Honors Capstone Projects - Archive

Programmed cell death (PCD) is an essential evolutionarily- conserved and genetically encoded program for normal development and homeostasis. A previous study identified a CED-3 dependent but mechanistically non-apoptotic and highly stereotyped elimination program called Compartmentalized Cell Elimination (CCE) in the C. elegans tail-spike epithelial cell (TSC). Here the transcription factor EOR-1/PLZF is found to promote CCE. The loss of which results in a persisting non-engulfed soma with enlarged nuclei in the first larval stage. This study finds that EOR-1 and its established partners function downstream of CED-3 Caspase protease activity, a role distinct from other PCD contexts where EOR-1 has …

Lack Of Inflammatory Response In Mouse Embryonic Cells To Listeria Infection, Damilola Oyebode

Master's Theses

Approximately 1 in 5 pregnancies in the United States results in miscarriage, with a significant percentage of these losses attributed to failed implantation due to immunological challenges encountered by the early embryo. Recent research has shown that key cell types within mouse blastocysts, including embryonic stem cells (ESCs) and trophoblast stem cells (TSCs), exhibit remarkable resilience against the cytotoxic effects associated with viral infections and embryotoxic cytokines, such as TNFα and IFNγ, both of which are known to hinder blastocyst development. However, the immune properties of the preimplantation stage embryo, specifically the blastocyst, remain poorly understood. Using mouse cell model, …

Investigation Of Reproductive Inhibition During Chronic Heat Stress In C. Elegans, Macy Makenna Nielander

Theses and Dissertations

Nearly all organisms experience heterogeneity in environmental conditions that can negatively impact fitness. A common adaptive strategy to reduce the impact of this stress is called facultative diapause, where development and reproduction are temporarily arrested to promote survival. Facultative diapause is characterized by three major criteria, the arrest must be (i) induced by an unfavorable environmental condition, (ii) reversible, and (iii) driven by genetically regulated mechanisms. The aim of this thesis was to determine whether chronic heat-induced inhibition of egg laying in Caenorhabditis elegans represents a novel form of facultative diapause. It was found that the inhibition of egg-laying is …

Phagolysosomes Break Down The Membrane Of A Non-Apoptotic Corpse Independent Of Macroautophagy, Shruti Kolli, Cassidy J. Kline, Kimya M. Rad, Ann M. Wehman

Biological Sciences: Faculty Scholarship

Cell corpses must be cleared in an efficient manner to maintain tissue homeostasis and regulate immune responses. Ubiquitin-like Atg8/LC3 family proteins promote the degradation of membranes and internal cargo during both macroautophagy and corpse clearance, raising the question how macroautophagy contributes to corpse clearance. Studying the clearance of non-apoptotic dying polar bodies in Caenorhabditis elegans embryos, we show that the LC3 ortholog LGG-2 is enriched inside the polar body phagolysosome independent of autophagosome formation. We demonstrate that ATG-16.1 and ATG-16.2, which promote membrane association of lipidated Atg8/LC3 proteins, redundantly promote polar body membrane breakdown in phagolysosomes independent of their role …

Autophagy And Meiotic Fidelity In C. Elegans, Kaitlin E. Kosinski

Dissertations, Theses, and Capstone Projects

Autophagy is an evolutionarily conserved multi-step recycling process in which cellular material is enclosed in the double membrane-bound autophagosome, which fuses with the lysosome to degrade its contents. Autophagy is essential for development and cellular adaptation to environmental or intracellular stress and is an important regulator of germline stem cell homeostasis in the model nematode C. elegans. We sought to determine if autophagy is important for genome stability during meiosis and found that the core adult C. elegans autophagy genes bec-1, atg-7, unc-51, and atg-18 were all required for proper meiotic development of oocytes. Loss of these …

Causes And Consequences Of Mitotic Chromosome Missegregation In Human Pluripotent Stem Cells, Chenhui Deng

Dartmouth College Ph.D Dissertations

Mitosis is a fundamental process that ensures the equal distribution of replicated chromosomes, which carry an organism's genetic material, into two daughter cells. The fidelity of mitosis is paramount, as errors in chromosome segregation result in aberrant chromosome numbers, including gains or losses, a state termed aneuploidy. Aneuploidy impacts a broad range of human conditions, including being one of the major hurdles in early human development where it is the primary cause of miscarriages and birth defects. Strikingly, more than 70% of human preimplantation embryos are aneuploid with mitotic chromosome segregation errors being the most common source of aneuploidy. However, …

The Role Of Edc3 In Drosophila Melanogaster Neuronal Development, Keelan Zius

Electronic Theses and Dissertations

Enhancer of mRNA-decay 3 (Edc3) is a component of multiple decapping complexes that regulates the transcriptome by targeting a subset of transcripts for decapping for 5’-to-3’ messenger RNA (mRNA) decay. A missense mutation in the conserved Lsm domain of Edc3 has been reported in two siblings presenting with mild, non-syndromic intellectual disability (ID), however, the role of Edc3 is neuronal development has never been evaluated. Here, we use the Drosophila melanogaster model system to investigate the effects of Edc3 disruption on neuronal development. We found Edc3 reduction leads to significant hyperplasia at the larval neuromuscular junction (NMJ), providing the first …

Morphological Remodeling Of The Endoplasmic Reticulum During Mitosis And Its Influence On The Integrity Of The Spindle Apparatus, Katie R. Rollins

Electronic Theses and Dissertations

The Endoplasmic Reticulum (ER) is the largest organelle in the cell by surface area and forms contacts with other organelles throughout the cell. In recent work, the ER has been implicated in numerous processes within the cell beyond its canonical roles of protein synthesis and calcium storage. The ER also undergoes a remarkable transition in morphology during cell division, with mitotic divisions requiring a massive remodeling of various membranous organelles such as the nuclear envelope and Golgi. However, whether changes in ER behaviors modulate mitotic events is less clear. The rapid cleavage divisions in the early Drosophila embryo are a …

High Mdmx (Mdm4) In Mutant P53 Expressing Breast Cancer Cells Activates The Cxcl12-Cxcr4 Metastasis Signaling Axis, Rusia H. Lee

Dissertations, Theses, and Capstone Projects

The metastasis-promoting G-protein coupled receptor (GPCR) CXCR4 is activated by the cytokine CXCL12 (also known as SDF-1) to promote metastasis through CXCR4 upregulation. High CXCR4-expressing cancer cells utilize CXCL12, the exclusive endogenous ligand of CXCR4, to intravasate into the blood as circulating tumor cells (CTCs) which then extravasate to distant metastatic sites. We previously determined the oncogenes, Mouse Double Minute 2 and 4 (MDM2 and MDM4, also known as MDMX), drive TNBC metastasis and positively correlate with high expression of CXCR4. Interestingly, this upregulation of CXCR4 was only observed in primary tumor cells grown in the tumor microenvironment …

Using Rapid Protein Degradation To Determine The Effect Of Runx1 Loss-Of- Function On Dna Damage Accumulation And Repair., Jackriel Pina Morales

Theses and Dissertations

Germline mutations in RUNX1 are associated with familial platelet disorder with a predisposition to myeloid malignancy (RUNX1-FPDMM), in which patients present with low platelet counts,excessive bleeding and bruising, and an increased risk of Acute Myeloid Leukemia (AML)/Myelodysplastic Syndrome (MDS) development throughout their lifetime. To understand how these loss-of-function mutations in RUNX1 drive predispose to malignancy, it is important to develop a detailed understanding of the molecular basis of RUNX1 function. While RUNX1 is a transcription factor, preliminary data from our group and work from others suggests that RUNX1 also interacts with proteins that are critical for DNA damage …

Towards A New Role Of Mitochondrial Hydrogen Peroxide In Synaptic Function, Cliyahnelle Z. Alexander

Student Theses and Dissertations

Aerobic metabolism is known to generate damaging ROS, particularly hydrogen peroxide. Reactive oxygen species (ROS) are highly reactive molecules containing oxygen that have the potential to cause damage to cells and tissues in the body. ROS are highly reactive atoms or molecules that rapidly interact with other molecules within a cell. Intracellular accumulation can result in oxidative damage, dysfunction, and cell death. Due to the limitations of H₂O₂ (hydrogen peroxide) detectors, other impacts of ROS exposure may have been missed. HyPer7, a genetically encoded sensor, measures hydrogen peroxide emissions precisely and sensitively, even at sublethal levels, during …

Unveiling The Nexus Of Cellular Quality Control: Exploring The Interplay Between Ribosome-Associated Protein Quality Control And Mitochondrial Quality Control Pathways, Foozhan Tahmasebinia

Biological Sciences Theses and Dissertations

In eukaryotic cells, the intricate interplay between cellular quality control mechanisms is crucial for maintaining homeostasis and safeguarding the integrity of vital processes, spanning from macromolecule synthesis to the renewal of entire cellular organelles.

Disruption of these networks can lead to severe diseases such as metabolic disorders, underscoring the interconnected nature and feedback control mechanisms inherent in biological systems, including cellular quality control systems. This interconnectedness extends to the intricate communication between organelles, enabling coordinated functioning and adaptation to changing cellular conditions, particularly in response to stressors.

While the exact mechanisms governing these communications within cellular quality control systems remain …

Regulation Of Intracellular Sorting Of The Bruno Protein In Drosophila Flight Muscles, Travis Main

Master's Theses

Understanding mechanisms of intracellular sorting is a fundamental inquiry of cell biology. We used the B-body and protein Bruno (Bru) as a model to study the formation of nuclear domains that are membraneless organelles inside the cell nucleus. Specifically, we sought to identify protein sequences that regulate Bru's affinity to B-bodies and protein aggregation. We generated various Bru mutants and subsequently tested them in vivo using fluorescence microscopy. We found that the protein solubility of Bru is determined through an interplay of RNA recognition motifs (RRMs) and intrinsically disordered regions (IDRs). Using truncation analysis, we identified a 31-amino acid region …

The Effect Of Diabetes Mellitus On Differentiation Of Mesenchymal Stem Cells Into Insulin-Producing Cells, Mohamed M. Kamal, Omar I. Badr, Shohda A. El-Maraghy, Heba R. Ghaiad

Pharmacy

Background

Diabetes mellitus (DM) is a global epidemic with increasing incidences. DM is a metabolic disease associated with chronic hyperglycemia. Aside from conventional treatments, there is no clinically approved cure for DM up till now. Differentiating mesenchymal stem cells (MSCs) into insulin-producing cells (IPCs) is a promising approach for curing DM. Our study was conducted to investigate the effect of DM on MSCs differentiation into IPCs in vivo and in vitro.

Methods

We isolated adipose-derived mesenchymal stem cells (Ad-MSCs) from the epididymal fat of normal and STZ-induced diabetic Sprague–Dawley male rats. Afterwards, the in vitro differentiation of normal-Ad-MSCs (N-Ad-MSCs) and …

Characterization Of Mitochondrial Morphology In Drosophila: Early Embryogenesis Description Via Confocal Microscopy, Kendall Miller

Biological Sciences Undergraduate Honors Theses

Mitochondria are not static organelles, but instead are dynamic networks that undergo rapid changes in subcellular distribution, organization, and activity in response to external stimuli. Notably, mitochondria can undergo fission and fusion, collectively known as mitochondrial dynamics. Mitochondrial fusion creates assembled networks of mitochondria that are maximally efficient at generating ATP through oxidative phosphorylation. Conversely, mitochondrial fission leads to network fragmentation and a shift towards glycolysis, which is the dominant mode of ATP generation in oxygen-limiting and stressed conditions. While mitochondrial dynamics have been intensively studied in isolated cells under stressful conditions, much less is known about how mitochondria behave …

The Role Of B Cell Activation State And Sex In Aryl Hydrocarbon Receptor Mediated Induction Of Chemokine Receptor 9 And Alpha4beta7 Expression In Vitro, Logan Bauerle

Master's Theses

Defense of mucosal tissues from microbial infection and allergy is reliant on continual production of antibodies. The aryl hydrocarbon receptor (AhR) is known to regulate B cell development and is associated with suppression of systemic humoral immunity. Recent attention has been paid to the role of the AhR in altering expression of cell adhesion molecules (CAMs). B cells express CAMs and chemokine receptors to migrate around the body for localized secretion of antibodies. AhR agonists promote B cell migration to the small intestine through upregulation of chemokine receptor 9 (CCR9) and integrin α₄β₇. Both the AhR …

Regulation Of Embryonic Eye Regrowth In Xenopus Laevis, Dylan Guerin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Regrowth of lost organs and tissues is an amazing ability that some animals possess. For regrowth to be considered full, the organism must regrow the organ or tissue to a state that is structurally and functionally similar to that which was lost. The ability of an organism to regrow lost or damaged tissue varies among animals, both in the mechanisms utilized to achieve regrowth, and in what body parts can be regrown. Potentially even closely related species can vary wildly in regenerative ability. Therefore, regenerative research can look to other tissues and organisms for direction in elucidating the mechanisms through …

Qualitative Assessment Of Human Embryonic- And Induced Pluripotent Stem Cell Derived Neural Stem Cells Under Cgmp Methods, Michelle Hernandez

Electronic Theses, Projects, and Dissertations

Neural stem cell therapies represent a promising tool for the development of regenerative medicine and are being tested in clinical trials for several neurological disorders. However, the clinical applicability of stem cell therapies is dependent on the implementation of current good manufacturing practices (cGMPs) to ensure the quality, safety, and consistency that stem cell products need to meet FDA regulatory requirements. As such, there is a need for a shift to xeno-free methodologies so experimental conditions are cGMP compliant. The purpose of this study is to test a GMP compatible production method to generate multipotent neural stem cells (NSCs) from …

Investigating The Mechanisms Through Which Autophagy Controls Lipid Levels In Cyst Stem Cells., Jared Langdon

College of Arts & Sciences Senior Theses

With an increase in the average age of the American population, incidents of age-related diseases and illnesses are rising across healthcare communities. Addressing these pathologies with a focus towards novel treatments warrants further research into their mechanistic origins. Lipid build up within cells has been correlated with increased risk for certain pathologies, namely Alzheimer's disease and type-2 diabetes (Demarco, 2020). In this study I aimed to investigate the origin of the increase in lipids, specifically we consider the effects of lipid build up on the maintenance of stem cell populations.

Ras/Mapk Signaling Mediates Adipose Tissue Control Of Ovarian Germline Survival And Ovulation In Drosophila Melanogaster, Tancia Bradshaw, Chad Simmons, Rachael Ott, Alissa Richmond Armstrong

Faculty Publications

From insects to humans, oogenesis is tightly linked to nutritional input, yet little is known about how whole organism physiology matches dietary changes with oocyte development. Considering that diet-induced adipose tissue dysfunction is associated with an increased risk for fertility problems, and other obesity-associated pathophysiologies, it is critical to decipher the cellular and molecular mechanisms linking adipose nutrient sensing to remote control of the ovary and other tissues. Our previous studies in Drosophila melanogaster have shown that amino acid sensing, via the amino acid response pathway and mTOR-mediated signaling function within adipocytes to control germline stem cell maintenance and ovulation, …

Functional Analyses Of The Polycomb-Group Genes In Sea Lamprey Embryos Undergoing Programmed Dna Loss, Cody Saraceno

Theses and Dissertations--Biology

During early embryonic development, the sea lamprey (Petromyzon marinus) undergoes programmatic elimination of DNA from somatic progenitor cells in a process termed programmed genome rearrangement (PGR). Eliminated DNA eventually becomes condensed into micronuclei, which are then physically degraded and permanently lost from the cell. Previous studies indicated that many of the genes eliminated during PGR have mammalian homologs that are bound by polycomb repressive complex (PRC) in embryonic stem cells. To test whether PRC components play a role in the faithful elimination of germline-specific sequences, we used a combination of CRISPR/Cas9 and lightsheet microscopy to investigate the impact …