Medical Cell Biology Commons^™

Role Of Smarce1 And Bhlhe40 In Breast Cancer Metastasis, Aarti Sethuraman

Theses and Dissertations (ETD)

No abstract provided.

Protein Trafficking Of Bk Channel Β1 Subunits In Cerebral Artery Myocytes, Xue Zhai

Theses and Dissertations (ETD)

Rationale: Large-conductance calcium (Ca²⁺)-activated potassium channels (BK) are expressed in arterial myocytes to control arterial contractility. It is composed of pore- forming BKα and auxiliary β1 subunits. Auxiliary β1 subunits associate with BKα which modulate Ca²⁺ sensitivity of BK channel. Previous data showed that BKα locates at cell membrane, whereas β1 subunits are primarily intracellular which regulated by Rab11A- positive recycling endosomes. Endothelin-1 (ET-1), a vasoconstrictor, induces contraction of myocytes. ET-1 inhibits BK channel but mechanisms are not fully understood. It is unclear that vasoconstrictors regulate the cellular distribution of BK channels. Furthermore, BK channels are involved …

Characterization Of The Hepatotoxicity Of Rifampicin And Isoniazid, Christopher T. Brewer

Theses and Dissertations (ETD)

In a mouse model, rifampicin and isoniazid combination treatment results in cholestatic liver injury that is associated with an increase of protoporphyrin ix (PPIX), the penultimate heme precursor. Excess PPIX is believed to bind to bile acids, precipitate in bile canaliculi, and form bile plugs leading to cholestasis fol owed by liver injury. Both ferrochelatase (FECH/Fech) and aminolevulinic acid synthase 1 (ALAS1/Alas1) are crucial enzymes in regulating heme biosynthesis. Isoniazid has recently been reported to up-regulate Alas1 but down-regulate Fech protein levels in mice; however the mechanism of isoniazid mediated heme synthesis …

Revealing A Non-Canonical Role Of Anti-Apoptotic Mcl-1 In Early Embryonic Development, Xue Yang

Theses and Dissertations (ETD)

MCL-1, a well-known pro-survival BCL-2 family member, is indispensable for the survival of various cellular lineages and is also among the most frequently amplified genes in a variety of human malignancies. Gene ablation studies previously revealed that Mcl-1 deficiency leads to embryonic lethality around E3.5 during peri-implantation stage. Strikingly, the study did not detect any increase in apoptotic cells of the blastocyst, indicating a function of MCL-1 beyond regulating apoptosis. Our previous studies revealed an unrecognized role of MCL-1 in promoting mitochondrial physiology, which is independent of its classical anti-apoptotic function and requires being imported into the mitochondrial matrix. In …

Metabolic Regulation Of Cellular Signaling, Rashid John Darbandi

Theses and Dissertations (ETD)

Using the biochemically tractable Xenopus oocyte model system, we have previously characterized a novel metabolic regulation of cell death. We found that glucose-6-phosphate (G6P) via the pentose phosphate pathway leads to increased nicotinamide adenine dinucleotide phosphate (NADPH) levels, a subsequent increase in cytosolic acetyl-coenzyme A and activation of Ca2+/calmodulin-dependent protein kinase II (CaMKII). We recently identified coenzyme A (CoA), derived from the breakdown of acetyl-CoA, as the key metabolic signal that mediates a novel mechanism of calmodulindependent activation of CaMKII. CoA binds directly to the calmodulin (CaM) binding domain (CaMBD) of CaMKII resulting in its activation and downstream inhibitory phosphorylation …

Genome-Scale Precision Proteomics Identifies Cancer Signaling Networks And Therapeutic Vulnerabilities, Hong Wang

Theses and Dissertations (ETD)

Mass spectrometry (MS) based-proteomics technology has been emerging as an indispensable tool for biomedical research. But the highly diverse physical and chemical properties of the protein building blocks and the dramatic human proteome complexity largely limited proteomic profiling depth. Moreover, there was a lack of high-throughput quantitative strategies that were both precise and parallel to in-depth proteomic techniques. To solve these grand challenges, a high resolution liquid chromatography (LC) system that coupled with an advanced mass spectrometer was developed to allow genome-scale human proteome identification. Using the combination of pre-MS peptide fractionation, MS2-based interference detection and post-MS computational interference correction, …

Cannabinoid Receptor 2 (Cb2) Ligands Downregulate Pro-Inflammatory Markers In Stimulated Primary Human Periodontal Ligament Fibroblasts (Hpdlfs), Ammaar Hasan Abidi

Theses and Dissertations (ETD)

There are approximately 743 million individuals suffering from chronic periodontitis (PD) making it the sixth most prevalent condition worldwide. The affected adult population in the U.S. are nearly 64.7 million and the healthcare costs exceeds $14 billion. Recently, host response to pathogenic infection has been seen critical to the progression of PD and exhibit increase in various inflammatory markers. Marijuana is well known for its recreational usage and is a risk factor for periodontal disease, which is seen as a concern in society for its negative health consequences. However, many medical conditions can benefit from the pharmacological effects of cannabinoids. …

Investigating The Role Of Dispatched In Hedgehog Ligand Transport And Delivery, William Bodeen

Theses and Dissertations (ETD)

During the development of all metazoans, the Hedgehog (Hh) signaling pathway provides instructional cues influencing a variety of cellular processes. The pathway ligand, Hh, is dually lipidated by cholesterol and palmitate, which effectively anchors the molecule to the lipid bilayer of the signal producing cell. To complicate the Hh pathway induction process, the Hh ligand is often produced at a significant distance from the cells it influences. Only one known conserved molecule, Dispatched (Disp), can alleviate the membrane tethering imparted by Hh lipidation. Underscoring the importance of Disp protein during development, knockout animals succumb to lethality at E9.5, an exact …

Therapeutic Effects Of Ormeloxifene In Cervical Cancer Carcinogenesis, Neeraj Chauhan

Theses and Dissertations (ETD)

Cervical cancer (CxCa) remains the fourth leading cause of cancer related deaths among women worldwide. Cervical cancer is mainly (~ 99.7%) derived from high risk Human papillomavirus (HR HPV). HPV E6/E7 are the two main oncoproteins that interfere with p53 and pRb (retinoblastoma) cell cycle regulatory proteins and hinder their efficacy of controlling cell growth. Additionally, PI3K-Akt is a cell survival pathway that is aberrantly expressed in cervical cancer cells. This pathway has a profound role in inhibiting mitochondrial intrinsic apoptotic signaling pathway. Advanced stage cervical cancer is difficult to treat and patients diagnosed with metastatic disease have a poor …

Role Of Dendritic Cells In Pathology Of Respiratory Syncytial Virus Infection In Neonates, Bishwas Shrestha

Theses and Dissertations (ETD)

Respiratory syncytial virus (RSV) is one of the leading causes of bronchiolitis in children. We have shown that neonatal mice respond to primary RSV infection with T helper type 2 (Th2) biased immune responses, which are enhanced following reinfection. Dendritic cells (DCs) including myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) play important roles in driving host responses to RSV infection. mDCs present antigens to help Th cells differentiate, and pDCs protect against viral infection through type I interferons (IFNs). Despite data demonstrating importance of mDCs and pDCs in protection against RSV, it has not been studied in an age appropriate …

Environmental Signaling Through The Target Of Rapamycin Complex 1 (Torc1) And The Regulation Of Epigenetic Mechanisms, Jason J. Workman

Theses and Dissertations (ETD)

The gene expression profile of a eukaryotic cell is responsive to a variety of extracellular stimuli, including nutrient availability, which allows cells to toggle between anabolism and catabolism based on the favorability of their environment. Much of this information is relayed through signaling complexes, such as the target of rapamycin complex 1 (TORC1), to downstream chromatin modifying enzymes. These enzymes impact the gene regulatory process through altered histone post-translation modifications, changes in chromatin structure, and docking of chromatin regulatory complexes. Yet, despite preliminary studies suggesting that TORC1 affects epigenetic mechanisms, including histone H3 lysine 56 acetylation (H3K56ac), almost nothing is …

Role Of Occludin In The Regulation Of Epithelial Tight Junctions, Bhargavi Manda

Theses and Dissertations (ETD)

Tight junctions (TJ) constitute the primary component of epithelial barrier function, a disruption of which is involved in the pathogenesis of many gastrointestinal, pulmonary and renal diseases. Occludin is the major transmembrane protein of TJ, a deletion of which leads to a complex phenotype including chronic inflammation in several epithelial tissues of occludin deficient mice and poor TJ integrity in epithelial cell lines. Its down regulation was seen in Crohn’s disease, tumors of the colon, brain, endometrium and breast cancer. Occludin is also known to be a target that enables Hepatitis C Virus infection and bacterial pathogenesis. But the specific …

The Nucleolar Protein Nucleophosmin Undergoes Liquid-Liquid Phase Separation With Arginine-Rich Nucleolar Proteins Through Weak, Multivalent Electrostatic Interactions, Jaclyn Alicia Cika

Theses and Dissertations (ETD)

Nucleoli are nuclear membrane-less organelles that are the sites for ribosome biogenesis and serve as sensors of cellular stress. Weak, multivalent protein-protein interactions and interactions between disordered, low complexity domains (LCDs) and rRNA have been shown to promote liquid-liquid phase separation (LLPS) in vitro, suggesting a basis for the liquid-like behavior of nucleoli. Nucleophosmin (NPM1), a multifunctional and highly abundant nucleolar protein, exhibits structural features associated with LLPS suggesting a role in nucleolar organization. Specifically, NPM1 forms a pentamer through its N-terminal oligomerization domain and can bind to rRNA through its C-terminal nucleic acid binding domain. Multiple acidic tracts throughout …

The Roles Of Nuclear Receptor Nr4a1 In Cancer Cell Proliferation And Skeletal Muscle Differentiation, Alexa Farmer

Theses and Dissertations (ETD)

Nuclear receptors (NRs) constitute a major class of drug targets in the treatment of various cancer types. NRs respond to cellular signals and become activated upon ligand binding to transcriptionally modulate expression of target genes. NR4A1 (Nur77) is a member of the NR4A family of nuclear receptors and displays an oncogenic profile in many cancer models. It is often upregulated in adult solid malignancies and is known to promote cell proliferation and survival. Knockdown studies of NR4A1 in cancer cell lines results in decreased cell growth and angiogenesis and increased apoptosis, suggesting NR4A1 is an oncogenic protein. Due to the …

Investigating The Regulation And Function Of The Nr4a Nuclear Receptors In Cancer, Jordan A. Beard

Theses and Dissertations (ETD)

The nuclear receptor (NR) superfamily represents a structurally-conserved group of ligand-regulated transcription factors. These proteins have critical roles in various physiological and pathological processes, including cancer, and have been targets of drug therapy. The orphan NR subfamily 4A (NR4A), which includes the NR4A1 (Nur77), NR4A2 (Nurr1), and NR4A3 (Nor-1) genes, has been implicated in adult solid tumors and has been characterized as pro-tumorigenic mediator of cell proliferation, transformation, migration, and drug resistance. Alternatively, in leukemia, NR4A1 and NR4A3 have been described as tumor suppressors in hematologic malignancies. Members of the NR4A family are commonly overexpressed in cancer and this has …

Pten Signaling In Regulatory T Cells And Inflammatory Disease, Sharad Krishna Shrestha

Theses and Dissertations (ETD)

Regulatory T (Treg) cells suppress CD4+ T cell responses during homeostasis and inflammation to prevent autoimmunity and other immune disorders. Although the transcriptional and epigenetic programs impacting Treg cell function have been extensively studied, the signaling and metabolic pathways underlying Treg stability and function are not fully understood. In this study, we determined the role of the phosphatase PTEN in Treg cells. We found that specific depletion of PTEN in Treg cells results in excessive TH1 and T follicular helper cells (TFH) responses, associated with elevated germinal center (GC) B cells and spontaneous development of autoimmune and lymphoproliferative disease in …

Structural-Based Investigation Of Fak And P130cas In Focal Adhesion, Chi Zhang

Theses and Dissertations (ETD)

Cell migration is an integrated multistep process accompanying us throughout life, from birth to death. It contributes to a variety of biological activities and has been implicated in many pathological conditions, including cancer, primary immunodeficiency diseases, vascular diseases, and mental retardation. Cell migration has been considered to be a three-step cyclic process including polarization, protrusion and retraction. The initiation and extension of the protrusion is driven by actin polymerization, and is stabilized by attaching to the extracellular matrix (ECM) or adjacent cells. The cell-ECM attachment sites are named focal adhesions (FAs), which are dynamic, large protein complexes containing more than …

Mrp4-Dependent Regulation Of Fibroblast Migration, Chandrima Sinha

Theses and Dissertations (ETD)

Roles of cyclic nucleotides and cyclic nucleotide-dependent signaling molecules in regulating several signaling pathways including cell migration have long been known. However, the new and revolutionary concept is that it is not just the absence or presence of cyclic nucleotides, but a highly coordinated balance between these molecules regulates cell migration. Multi-drug resistance protein 4 (MRP4), is a member of the large family of ATP binding cassette (ABC) transporter proteins, that localizes to the plasma membrane and functions as a nucleotide efflux transporter and thus plays a pivotal role in the regulation of intracellular cyclic nucleotide dynamics. In our study …

Novel Insights Into The Role Of The Smoothened Cysteine Rich Domain In Hedgehog Signalling, Rajashree Rana

Theses and Dissertations (ETD)

The Hedgehog (Hh) signal transduction pathway functions as one of the key developmental pathways and deranged Hh signalling is associated with numerous cancer and tumor conditions. The Smoothened (Smo) G protein coupled receptor (GPCR) functions as the signal transducer of the Hh pathway and is the most attractive drug target of the pathway. The structure of the Smo receptor includes seven membrane spanning domains, extracellular and intracellular loops connecting the membranous domains and the extracellular cysteine rich domain (CRD). The extracellular CRD of the Smo receptor is homologous to the Frizzled (FzD) CRD. The FzD CRD interacts with the physiological …

Functional And Genetic Analysis Of Choroid Plexus Development In Zebrafish, Hannah Elizabeth Henson

Theses and Dissertations (ETD)

The choroid plexus (CP) is an epithelial based structure localized within the brain ventricles and functions as the blood-cerebrospinal fluid barrier (BCSFB). Under normal conditions, the CP is responsible for generating the cerebrospinal fluid (CSF) and regulating its components. Abnormal CP function has been associated with neurodegenerative diseases, tumor formation in CP epithelia (CPe), and hydrocephalus. Despite the significant role of the CP in these disorders, little research has been done to characterize its functional properties and genetically dissect the pathways involved in normal CP development and disease. For this study, we have utilized zebrafish, (Danio rerio), as a model …

The Mi-2 Homolog Mit1 Actively Positions Nucleosomes Within Heterochromatin To Suppress Transcription, Kevin M. Creamer

Theses and Dissertations (ETD)

Eukaryotic DNA is packaged into the nucleus in complex with proteins that regulate access and utilization of the genetic material. These DNA and protein complexes form a dynamic structure known as chromatin. Nucleosomes are the repeating unit of chromatin, and consist of DNA wrapped around an octamer of histone proteins. Nucleosomes can then be modified and spatially arranged to facilitate processes such as transcription, DNA replication, and repair. A special transcriptionally repressive chromatin structure assembles onto gene-poor, repetitive regions of the genome known as constitutive heterochromatin. Mit1 is the putative chromatin remodeling subunit of the fission yeast Snf2/HDAC repressor complex …

Molecular Characterization Of Glioblastoma Cancer Stem Cells, Jo Meagan Garner

Theses and Dissertations (ETD)

Malignant gliomas are locally aggressive, highly vascular tumors that have an overall survival time less than 14 months, and current therapies provide little improvement in the disease course and outcome. While glioblastoma multiforme (GBM) patients present uniform histological phenotypes, the molecular determinants of the disease vary considerably between individual cases resulting in complicated prognosis. The heterogeneity, aggressiveness and rapid tumor relapse of GBM is believed to be sustained by cancer stem-like cell populations that are able to initiate and maintain tumors. Although CSCs represent only a small fraction of cells within a tumor, their high tumor-initiating capacity and therapeutic resistance …

Nkg2d Ligands In Cancer, Neha Das Gupta

Theses and Dissertations (ETD)

NK cell transplantation has been increasingly used to treat cancers that are resistant to chemotherapy. However, not all cancers are susceptible to NK cell killing. The prevalence and mechanisms of NK cell resistance have not been well elucidated. Because NKG2D is a major activating receptor on NK cells, we sought to test the hypothesis that NKG2D is the primary pathway in tumor cell recognition. Herein, we comprehensively assessed 20 cancer cell lines representing a broad array of cancer types. In line with our primary hypothesis, no cancer cell lines that expressed low levels of NKG2D ligands were susceptible to NK …

Adenylyl Cyclase 2 Selectively Regulates Il-6 Expression In Human Bronchial Smooth Muscle Cells, Amy Sue Bogard

Theses and Dissertations (ETD)

Adenylyl cyclase (AC) catalyzes the formation of the ubiquitous second messenger cAMP. AC isoforms differ in their tissue distribution, cellular localization, regulation, and protein interactions, and most cells express multiple isoforms. We hypothesized that cAMP produced by different AC isoforms regulates unique cellular responses. Overexpression of individual isoforms had distinct effects on forskolin (Fsk)-induced expression of a number of known cAMP-responsive genes in human bronchial smooth muscle cells (BSMC) and human embryonic kidney cells (HEK-293). Most notable, in BSMC overexpression and activation of AC2 enhanced interleukin 6 (IL-6) expression, but overexpression of AC3 or AC6 had no effect. IL-6 production …

Regulation Of Secretory Phospholipase A2 By Thyroid Hormone, Pragya Sharma

Theses and Dissertations (ETD)

Rationale: Low grade inflammation has been correlated with elevated risk of hepatic steatosis and atherosclerosis. Secretory phospholipase A2 group IIA (PLA2g2a) enhances the progression of several chronic inflammatory diseases including arthritis and atherosclerosis. The potential linkage of hypothyroidism with inflammation led us to examine the modulation of sPLA2 expression by thyroid hormone (T3) in liver.

Objective: Most of the studies of phospholipase A2 group IIA (PLA2g2a) have been conducted with macrophages and vascular smooth muscle cells with regard to atherosclerosis. The liver is one of the major contributors to the total pool of extracellular PLA2g2a. The aim of the present …

Macromolecular Complexes Of Cystic Fibrosis Transmembrane Conductance Regulator Alter Fluid Transport In Inflammatory Bowel Disorders, Kavisha Arora

Theses and Dissertations (ETD)

Macromolecular complexes of cystic fibrosis transmembrane conductance regulator (CFTR) comprise of network of proteins that can regulate cAMP-/cGMP-activated CFTR chloride channel function. We report the physical and functional coupling of CFTR with nitric oxide (NO) producing enzyme-inducible nitric oxide synthase (iNOS) at the apical plasma membrane in inflammatory bowel disease (IBD). The complex formation requires the scaffolding protein Na+ /H+ exchanger regulatory factor 2 (NHERF2). We demonstrate that iNOS is overexpressed at or near the apical plasma membrane of gut epithelial cells in IBD and, through the stimulation of the NO-cGMP pathway, generates compartmentalized cGMP underneath the plasma membrane. This …

The Protumorigenic Role Of Caspase-8 In Neuroblastoma, Devin Drew Twitchell

Theses and Dissertations (ETD)

Neuroblastoma (NB), the most common extracranial solid tumor in children, accounts for 15% of cancer-related deaths in pediatric patients. Caspase-8 (casp8), a proapoptotic protein, is silenced in approximately, 50-70% of neuroblastoma patient samples. Loss of casp8 has been suggested to increase NB metastasis and correlated, in some studies, with advanced-stage NB. Furthermore, decreased casp8 expression may facilitate neuroblastoma tumorigenesis by protecting cells from cell death mediated by either integrins or chemotherapeutics. Paradoxically, casp8 expression is maintained in 30-50% of NB patient samples giving rise to the possibility that casp8 may provide selective advantages for NB tumorigenesis. Caspase-8 is shown to …

Functional Study Of Hemogen Knockout Mouse Model, Peng Gao

Theses and Dissertations (ETD)

Mouse Hemogen (Hemgn) is regarded as a homologue of human Erythroid Differentiation Associated Gene (EDAG). EDAG overexpression has been postulated for association with some leukemia cases. Meanwhile, Hemgn has been found to contribute to Hoxb4 mediated hematopoietic stem cell expansion. Based on these postulations and evidences, a Hemgn knockout mouse model has been generated to study its function in normal and stress hematopoiesis. I confirmed the Hemgn expression in hematopoietic organs including bone marrow and spleen, as well as round spematids in testis. Hemgn is expressed in mouse hematopoietic stem cells and erythroid progenitor cells. Moreover, Hemgn was also found …

Hematopoietic Stem Cell Threshold Sensing Controls Regulatory Pathways Facilitating Clinically Relevant Ex Vivo Expansion For Stem Cell Transplantation, Andrew D. Lasiter

Theses and Dissertations (ETD)

The ex vivo expansion of hematopoietic stem cells (HSCs) for transplantation has threefold importance: 1.) First, because of the rarity of stem cells there often isn’t a sufficient supply obtainable from common sources for larger children and adults. 2.) Secondly, patient morbidity and time to hematopoietic reconstitution following myeloablative preconditioning is improved by administering a larger pool of HSCs. 3.) Lastly, gene therapies for hematological diseases still require a robust supply of HSCs to offset varying degrees of inefficiency in vector mediated transfection protocols. These reasons, and others, have been an impetus for many discoveries made within four primary subdivisions …

Mrp4 Is A Crucial Regulator Of Testosterone Biosynthesis, Jessica Ann Morgan

Theses and Dissertations (ETD)

The physiological role of multidrug resistance protein 4 (Mrp4) in the testes is unknown. It was discovered that Mrp4 is expressed primarily in mouse and human Leydig cells; however, there is no current evidence that Mrp4 regulates testosterone biosynthesis. The role of Mrp4 was investigated in Leydig cells where testosterone production is regulated by cAMP, an intracellular second messenger formed when the luteinizing hormone (LH) receptor (Lhr) is activated. As Mrp4 regulates cAMP, we compared testosterone levels in our Mrp4 WT and KO mice. Prepubertal KO mice had significantly reduced testicular testosterone, impaired gametogenesis, and disrupted cAMP homeostasis, resulting in …