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Full-Text Articles in Life Sciences

Tissue-Resident Myeloid-Derived Suppressor Cells Modulate Immune Homeostasis In Healthy Adipose., Katlin Brooke Stivers Aug 2020

Tissue-Resident Myeloid-Derived Suppressor Cells Modulate Immune Homeostasis In Healthy Adipose., Katlin Brooke Stivers

Electronic Theses and Dissertations

Our goal with this study was to gain insight into the homeostatic immune cell network in healthy adipose tissue. Specifically, we sought to determine if the immature myeloid cells found in healthy and inflamed adipose were, in fact, tissue-resident myeloid-derived suppressor cells (MDSCs). Using various in vitro and in vivo methods, we have uncovered a population of CD11bHi Ly6CHi Ly6G- MDSCs resident in healthy adipose tissue. To the best of our knowledge this is the first time that these cells have been investigated and described in healthy adipose tissue. Systemic MDSC depletion lead to the accumulation of …


A Novel Role For Rassf1a In The Regulation Of Ras Activation., Desmond Ramón Harrell Stewart Aug 2020

A Novel Role For Rassf1a In The Regulation Of Ras Activation., Desmond Ramón Harrell Stewart

Electronic Theses and Dissertations

Ras is the most frequently activated oncogene in human cancer. It is not only the most frequently mutated oncogene, but is also rendered hyperactive in the wild-type form by aberrant regulation. Ras drives transformation and contributes to tumor aggressiveness by activating multiple downstream mitogenic effectors. Ras also possesses the paradoxical ability to induce apoptosis and senescence. Ras-induced apoptosis is not well understood, but has been largely attributed to the RASSF tumor suppressors, particularly RASSF1A. RASSF1A mediates Ras-induced apoptosis by activating pro-apoptotic proteins such as the MST kinases and BAX. RASSF1A is among the most frequently inactivated tumor suppressors in human …


Development Of In Vitro Models To Study The Rapid Extraintestinal Dissemination Of Salmonella., Adarsh Gopinath May 2020

Development Of In Vitro Models To Study The Rapid Extraintestinal Dissemination Of Salmonella., Adarsh Gopinath

Electronic Theses and Dissertations

Salmonella appears in the bloodstream of mice in as little as 15 minutes after oral inoculation and establishes persistent colonies in the spleen and liver. While its pathway to blood is undetermined, this phenomenon is dependent on the activity of Salmonella pathogenicity island 2 (SPI-2) coded type III secretion system (T3SS) and CD18+ phagocytes. We hypothesize that dendritic cells associated with the basal face of the gut epithelium, that are naturally migratory and known to sample for luminal antigens directly transport Salmonella to the bloodstream. This process comprises of at least two phases, dissociation and reverse transmigration. We define dissociation …


In Situ Analysis Of Line-1 Promoter Activity Using Lacz Transgenic Mice, Partha Sarathi Saha Jan 2020

In Situ Analysis Of Line-1 Promoter Activity Using Lacz Transgenic Mice, Partha Sarathi Saha

Electronic Theses and Dissertations

Apart from an evolutionary role, transposable elements have been implicated in animal development and also in pathophysiology. Non-LTR retrotransposons– LINE-1, Alu and SVA - are responsible for over 120 cases of human genetic diseases as heritable insertions, and are emerging as an important etiological factor for cancer and neurological disorders as somatic mutations. It is estimated that among the total number of 500,000 LINE-1s presents in the human genome, 80-100 LINE-1s remain competent for retrotransposition. Retrotransposition is only possible when LINE-1 is expressed. Because LINE-1 transcription is regulated by its 5’UTR promoter, it is essential to understand the spatiotemporal control …


The Role And Molecular Mechanisms Of Wss1 In Preserving Genomic Stability, Daniel Kwesi Sam Jan 2020

The Role And Molecular Mechanisms Of Wss1 In Preserving Genomic Stability, Daniel Kwesi Sam

Electronic Theses and Dissertations

Cells are constantly under threat from both exogenous and endogenous sources of DNA damage. Eukaryotic organisms, however, possess conserved mechanisms that accurately and faithfully respond to DNA damage. The inability to effectively remove DNA lesions can lead to an accumulation of mutations which can compromise cellular viability. The DNA damage response is conserved from bacteria to eukaryotic organisms and have been well characterized, however, how covalently crosslinked proteins are removed from DNA remains enigmatic This thesis provides genetic and biochemical evidence implicating Wss1, a yeast metalloprotease in genome maintenance. We have identified SUMOylation to be an important signal that mediates …


Crispr/Cas9 Whole Genome Screens Reveal Novel Regulators Of Endocytic Processes In Macrophages, Jared Wollman Jan 2020

Crispr/Cas9 Whole Genome Screens Reveal Novel Regulators Of Endocytic Processes In Macrophages, Jared Wollman

Electronic Theses and Dissertations

Macrophages maintain tissue homeostasis by identifying and eliminating threats within their tissue microenvironment. Pattern recognition receptors allow macrophages to recognize and internalize specific ligands while macropinocytosis allows the internalization of all extracellular solutes from their environment. Without pattern recognition receptors, pathogens may grow unchecked if they cannot be detected, and without macropinocytosis, macrophages struggle to detect and move around their environment. This thesis presents the results of CRISPR/Cas9 whole-genome screens used to identify the regulators of both endocytosis (Chapter 2) and macropinocytosis (Chapter 3). In Chapter 2, we report genes regulating dextran uptake in primary murine macrophages and reveal Mrc1-mediated …


Cellular And Developmental Insights Into The Early Evolution Of Muscle, Jeffrey J. Colgren Jan 2020

Cellular And Developmental Insights Into The Early Evolution Of Muscle, Jeffrey J. Colgren

Electronic Theses and Dissertations

Whereas a great deal has been learned about the molecular underpinnings of morphological evolution in animals, much less is known about the origin of novel cell and tissue types. During the time in which the earliest animal lineages were diversifying, fundamental cell and tissue types, such as muscles, arose. Sponges are one of two animal lineages that lack muscles, yet they undergo coordinated full body contractions. Whereas the signaling processes have been studied, the physical mechanisms of contraction are completely uncharacterized. The main purpose of this work is to understand the primary contractile tissue of the sponge Ephydatia muelleri, …


Quantification Of Mitochondrial Zinc Homeostasis And Analysis Of Zinc And Polyamine-Mediated Axonal Trafficking, Dylan Hunt Fudge Jan 2020

Quantification Of Mitochondrial Zinc Homeostasis And Analysis Of Zinc And Polyamine-Mediated Axonal Trafficking, Dylan Hunt Fudge

Electronic Theses and Dissertations

The zinc ion is an important emerging signaling molecule for biological processes. In this work we engineered improved zinc sensors based on our previously developed fluorescent sensor GZnP1 to provide sensors with a higher fluorescent readout, faster kinetics, and a superior sensitivity to zinc. We utilized these zinc sensors and further developed the sensors to answer questions pertaining to biological zinc. We showed the labile zinc concentration in the mitochondrial matrix was less than 1 pM while the labile zinc concentration in the cytosol and mitochondrial IMS were comparable (~100 pM) across four different cell lines. Using these zinc sensors …


Sorting Of Cargo Proteins Within The Regulated Secretory Pathway: The Peripheral Membrane Protein Hid-1 As A Sorting And Vesicle Biogenesis Factor, Blake H. Hummer Jan 2020

Sorting Of Cargo Proteins Within The Regulated Secretory Pathway: The Peripheral Membrane Protein Hid-1 As A Sorting And Vesicle Biogenesis Factor, Blake H. Hummer

Electronic Theses and Dissertations

Large dense core vesicles (LDCVs) form at the trans-Golgi network (TGN) and mediate the regulated release of neuropeptides and peptide hormones. Despite their central role to physiology, the mechanisms controlling biogenesis and sorting to LDCVs is not well understood. Optimizing the retention using selective hooks (RUSH) method in neuroendocrine cells, we show it is possible to visualize sorting to the constitutive and regulated secretory pathways in real-time and that the bulk of transmembrane LDCV cargoes do not sort directly onto LDCVs, but exit the TGN into non-regulated vesicles to be incorporated to LDCVs at a later step. Additionally, we characterize …


Quantification Of Dynamic Epithelial Sheet Architecture In Botryllus Schlosseri Using 2-D & 3-D Image Analysis, Roopa Madhu Jan 2020

Quantification Of Dynamic Epithelial Sheet Architecture In Botryllus Schlosseri Using 2-D & 3-D Image Analysis, Roopa Madhu

Electronic Theses and Dissertations

Epithelial tubules form critical structures in various body tissues; how- ever, since they are difficult to access experimentally, their architecture and dynamics are not well understood. Here we examine the dynamic remodeling of epithelial tubes in vivo using a novel and uniquely accessible model system: the extracorporeal vasculature of Botryllus schlosseri (sea squirt). In Botryllus, massive retraction of blood vessels can be triggered without loss of barrier function, through (i) disrupting collagen crosslinking in the basement membrane using β-aminopropionitrile (BAPN); or (ii) disrupting the integrin pathway through inhibition of focal adhesion kinase (FAK). We performed stereographic projections of 3-dimensional …


Cellular And Organismal Ramifications Of De Novo Purine Synthesis Dysregulation, Randall Craig Mazzarino Jan 2020

Cellular And Organismal Ramifications Of De Novo Purine Synthesis Dysregulation, Randall Craig Mazzarino

Electronic Theses and Dissertations

Purines are a class of nitrogenous bases and are essential small molecules to life. Purines are used within the cell as genetic information carriers, energy currency, signaling molecules, and cofactors for multiple processes. They are formed through de novo and salvage pathways found in cells across the phylogenetic tree. The substrates of enzymes within de novo purine synthesis are known to influence other processes within the cell, such as energy homeostasis. In humans, de novo purine synthesis disorders are rare, with around 100 people identified. These patients exhibit a range of phenotypes, with varying degrees of mental retardation, seizure activity, …


Ehbp1 And Ehd2 Regulate Dll4 Caveolin-Mediated Endocytosis During Blood Vessel Development, Amelia Margaret Webb Jan 2020

Ehbp1 And Ehd2 Regulate Dll4 Caveolin-Mediated Endocytosis During Blood Vessel Development, Amelia Margaret Webb

Electronic Theses and Dissertations

During angiogenesis, the development of new blood vessels from existing vessels, there must be tight regulation between a leading tip cell and trailing stalk cells during vascular patterning. Lateral inhibition produced by Notch signaling is central to the specification and maintenance of tip and stalk cells in growing angiogenic sprouts. The Notch pathway is activated by the ligand Delta at adherens junctions between tip and stalk cells. Despite the centrality of Delta/Notch signaling to angiogenesis, relatively little is known about the mechanism of this signaling event. It has been proposed that the force generated by the Notch bound Delta ligand …


Actin Regulation And Furrow Dynamics During Early Drosophila Embryogenesis, Yi Xie Jan 2020

Actin Regulation And Furrow Dynamics During Early Drosophila Embryogenesis, Yi Xie

Electronic Theses and Dissertations

Drosophila embryogenesis starts with a single nucleus undergo 13 rounds of nuclear divisions called syncytial cycles. Staring at cycle 10 when nuclei migrate to the surface of the embryo, massive and dynamic cortical actin structures and cleavage furrow formations occur. How actin regulators coordinate into an organized network directing three-dimension actin structures in the developing organisms is an unsolved question. Here, I present an in-depth characterization of actin cap dynamics: the actin caps go through expansion, stabilization, elongation and fragmentation phases in each cycle. Arp2/3 is the major contributor to actin cap formation. The functions of 7 different actin and …


Exploring The Properties Of Chitin For Promoting Tissue Engineering And Repair, M. Jahir Raihan Jan 2020

Exploring The Properties Of Chitin For Promoting Tissue Engineering And Repair, M. Jahir Raihan

Electronic Theses and Dissertations

No abstract provided.