Developmental Biology Commons^™

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 …

Exploring The Links Among Brain Iron Accumulation, Cognitive Performance, And Dietary Intake In Older Adults: A Longitudinal Mri Study, Valentinos Zachariou, Colleen A. Pappas, Christopher E. Bauer, Elayna R. Seago, Brian T. Gold

Neurology Faculty Publications

This study evaluated longitudinal brain iron accumulation in older adults, its association with cognition, and the role of specific nutrients in mitigating iron accumulation. MRI-based, quantitative susceptibility mapping estimates of brain iron concentration were acquired from seventy-two healthy older adults (47 women, ages 60–86) at a baseline timepoint (TP1) and a follow-up timepoint (TP2) 2.5–3.0 years later. Dietary intake was evaluated at baseline using a validated questionnaire. Cognitive performance was assessed at TP2 using the uniform data set (Version 3) neuropsychological tests of episodic memory (MEM) and executive function (EF). Voxel-wise, linear mixed-effects models, adjusted for longitudinal gray matter volume …

Neurobiological Variables Mediating The Relationship Between Breast Cancer And Sleep Disruption, Brittany Domenique Elliott

Graduate Theses, Dissertations, and Problem Reports (ETD)

Neurobiological Variables Mediating the Relationship between

Breast Cancer and Sleep Disruption

Brittany D. Elliott, MS

Breast cancer is the most commonly diagnosed malignancy in women, with more than two million new cases diagnosed world-wide each year. Improvements in screening technology and diagnostics have increased survival rates, but cancer-associated sleep disruptions persist for the majority of breast cancer survivors well beyond the treatment period. In addition to reducing quality of life, reduced sleep quality is associated with greater incidences of affective dysfunction, reduced treatment efficiency, aggressive cancer progression, increased symptom severity, and increased mortality by all causes. Thus, identifying the variables …

Environmental Pollution And Early-Life Metabolic Programming, Lisa Koshko

Wayne State University Dissertations

Substantial evidence demonstrates that parental pollutant exposures can induce harmful health effects in the offspring, including the predisposition to Type II Diabetes. As rates of Type II Diabetes continue to rise in younger populations, a crucial gap lies in understanding the role of parental influence in the etiology of later-life metabolic disease. Therefore, the central goal of this work was to determine how early life exposure to smoking level benzene, an endocrine-disrupting air pollutant, affects the metabolic health of offspring, and to identify potential developmental mechanisms involved in disease susceptibility. This goal was achieved using two models of early life …

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 …

Pharmacological Or Genetic Inhibition Of Ltcc Promotes Cardiomyocyte Proliferation Through Inhibition Of Calcineurin Activity, Lynn A. C. Devilée, Abou Bakr M. Salama, Jessica M. Miller, Janice D. Reid, Qinghui Ou, Nourhan M. Baraka, Kamal Abou Farraj, Madiha Jamal, Yibing Nong, Todd K. Rosengart, Douglas A. Andres, Jonathan Satin, Tamer M. A. Mohamed, James E. Hudson, Riham R. E. Abouleisa

Markey Cancer Center Faculty Publications

Cardiomyocytes (CMs) lost during ischemic cardiac injury cannot be replaced due to their limited proliferative capacity. Calcium is an important signal transducer that regulates key cellular processes, but its role in regulating CM proliferation is incompletely understood. Here we show a robust pathway for new calcium signaling-based cardiac regenerative strategies. A drug screen targeting proteins involved in CM calcium cycling in human embryonic stem cell-derived cardiac organoids (hCOs) revealed that only the inhibition of L-Type Calcium Channel (LTCC) induced the CM cell cycle. Furthermore, overexpression of Ras-related associated with Diabetes (RRAD), an endogenous inhibitor of LTCC, induced CM cell cycle …

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 …

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 …

Investigation Of Chondrogenesis, Myogenesis, And Osteogenesis After 2,4-Dtbp, 2-Bp, 4-Bp, 3,5-Dtbc Exposure In Zebrafish, Haley Brashears

All Theses

Synthetic phenolic antioxidants (SPAs) are used in personal care products, food packaging, and water pipes, common SPAs include 2,4-di-tert-butylphenol (2,4-DTBP), 2-tert-butyl phenol (2-BP), and 4-tert-butyl phenol (4-BP). These compounds are detected in the environment and in human biological samples. 2,4-DTBP has been detected in cord plasma, placenta, and breast milk samples. This drives the concern regarding developmental toxicity. In human iPS cells 2,4-DTBP impairs differentiation into somites and osteoblasts. Other SPAs, like 2,6-di-tert-butyl-hydroxytoluene caused increased rates of malformations including yolk and pericardial edema, and spinal curvature in 5-day post fertilization (dpf) zebrafish. …

Size Matters: The Characterization Of Telomere Function In Germ Cell Development In Danio Rerio, Jessica Macneil

Graduate Doctoral Dissertations

Infertility is a growing problem worldwide. According to the WHO, 48 million couples across the globe suffer from infertility and many couples turn to Assisted Reproductive Technology (ART) to become pregnant. One readout of gamete quality and successful ART is telomere integrity because telomeres are necessary for chromosome movements during meiosis so that the segregation of chromosomes happens correctly. Telomeres are well known for their role in aging; however, they play an important and understudied role during meiosis. In meiosis, telomeres attach to the nuclear envelope (NE) via a protein chain spanning the NE that interacts with cytoplasmic motor proteins, …

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, …

The Role Of Wt1 In Müllerian Duct Development, Jace Aloway

Dissertations and Theses (Open Access)

WT1 is a zinc finger transcription factor widely expressed in the urogenital system. Human mutations of WT1 lead to pediatric nephroblastoma as well as frequent differences of sex development (DSDs). Previous studies have suggested that WT1 acts as an activator for Amhr2, a necessary component of typical male differentiation. We used the mouse as a model to investigate the role of WT1 in sex development, where we deleted Wt1 in the Müllerian duct (MD) mesenchyme using a novel conditional null reporter allele, Wt1 flox-RFP. This allele utilizes the Cre-lox system to delete exons 8 and 9 of Wt1 …

Functional Analysis Of The Zebrafish Orthologs Of Host Cell Factor 1 Gene, David Paz

Open Access Theses & Dissertations

Host Cell Factor C1 (HCFC1) is a transcriptional co-activator factor that regulates the expression of over 5000 different downstream target genes in human cells. Missense mutations in the HCFC1 gene cause methylmalonic acidemia homocysteinemia cblX type (cblX). cblX, a multiple congenital anomaly syndrome (MCA) characterized by abnormal brain development, craniofacial abnormalities, metabolic deficits, and intractable epilepsy. Published studies suggest that HCFC1 regulates neural precursor proliferation, number, and differentiation. However, these results were derived from studies that were performed with nonsense alleles or transient knockdown approaches. Although these results demonstrate the importance of HCFC1 in brain development, they do not replicate …

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 …

Old Vs. New: An Experiment On The Efficacy Of Complexity-Focused Reproductive Biology Lectures For Undergraduate Biology Students, Ive N. Muse, Shraddha Patel, Linda Fuselier

The Cardinal Edge

Old vs. New: An Experiment on the Efficacy of Complexity-focused Reproductive Biology Lectures for Undergraduate Biology Students

Muse, Ive N.; Patel, Shraddha; Fuselier, Linda

Abstract

Undergraduate reproductive biology courses are traditionally taught in a reductive manner, prioritizing a binary understanding of sex which oversimplifies reproductive behaviors and reproductive system development across diverse taxa. Although this binary approach to lessons on reproduction is intended to benefit students in learning foundational human reproductive concepts, it does not teach the most recent research in reproductive biology, which identifies reproductive variation as the norm. The current study designed and implemented a lesson on reproductive …

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 …

Role Of Sds-22/Pp1 Phosphatase In Polarizing The Germplasm Of Caenorhabditis Elegans Embryo, Aparna Nurni Ravi

Dartmouth College Ph.D Dissertations

During asymmetric cell division, cell polarity and cell cycle are tightly coupled to ensure robust segregation of cell fate determinants and generation of cellular diversity. In the one-cell C. elegans embryo, multiple cell cycle kinases regulate cell polarization and posterior segregation of germline fate determinants (germplasm). For example, PLK-1 kinase inhibits the retention of its germplasm substrate POS-1 in the anterior, driving POS-1 segregation to the posterior (Han et al., 2018). Additionally, MBK-2 kinase disassembles P granules in the anterior through phosphorylation of the P granule scaffold MEG-3, helping to drive P granule segregation to the posterior (Wang et al., …