Medicine and Health Sciences Commons^™

Protein S In Coagulation And Inflammation, Martha Mega Silvia Sim

Theses and Dissertations--Molecular and Cellular Biochemistry

Protein S (PS) is a key regulator, which links inflammation and coagulation and performs multiple proposed functions in both processes. PS exists in the blood as a free soluble form (~40%), bound to complement component 4b-binding protein/ C4BP (~60%), and packaged in platelet α-granules (~2.5%). Subendothelial tissue factor (TF), upon exposure to blood, initiates coagulation, a proteolytic cascade which results in the activation of thrombin, the enzyme responsible for formation of a fibrin clot. PS is a critical anticoagulant that inhibits multiple steps of this process. Only the free fraction of PS has full anticoagulant properties, as C4BP blocks this …

Defining Patient Cohorts For Guiding Clinical Trials And Treatment In Lafora Disease: A Model For The Rare Disease Community, Katherine Janae Donohue

Theses and Dissertations--Molecular and Cellular Biochemistry

In the US, approximately 8000 rare diseases have been identified. Combined, rare diseases impact more than 30 million people in the U.S. alone, with 75% of those being children. However, research, funding, and therapeutic development for the rare disease community remains challenging because of the incredible diversity – not only between diseases, but often even within a single disease.

LD is an ultra-rare childhood dementia and epilepsy caused by mutations in one of two driver genes: EPM2A, which encodes for the glycogen phosphatase laforin, and EPM2B/NHLRC1, which encodes the E3 ubiquitin ligase malin. Children with LD …

A Biochemical Characterization Of The Fusion Proteins From Enveloped Rna Viruses, Chelsea T. Barrett

Theses and Dissertations--Molecular and Cellular Biochemistry

Enveloped viruses must bind target cells and then fuse the viral membrane with a cell membrane to enter a host cell. These viruses use one or more surface glycoproteins to carry out these critical functions. The surface glycoprotein that carries out the fusion function, termed a fusion protein, is divided into three classes based on structural similarities. Some of the most studied human viral pathogens, such as human immunodeficiency virus (HIV), Ebola virus, influenza, measles, and the recently emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), possess class I fusion proteins. Following synthesis, class I fusion proteins associate as non-covalently …

Pre-Clinical Advancements In Biomarkers, Tools, And Therapeutics For A Metabolic Neurodegenerative Disease, Zoë Simmons

Theses and Dissertations--Molecular and Cellular Biochemistry

Glycogen is the storage form of glucose and a highly important substrate for cellular metabolism. Characterization of the enzymes and mechanisms of glycogen metabolism began over 70 years ago and over the last 20 years, a previously unknown protein called laforin has emerged as an important contributor to glycogen metabolism homeostasis. Multiple labs demonstrated that laforin is a glycogen phosphatase and mutations in the gene encoding laforin cause the formation of aberrant glycogen-like aggregates called Lafora bodies (LBs). LBs are cytoplasmic, water-insoluble aggregates that drive neurodegeneration and early death in Lafora disease (LD) patients. The direct relationship between mutated laforin, …

Entry And Early Infection Of Non-Segmented Negative Sense Rna Viruses, Jean Mawuena Branttie

Theses and Dissertations--Molecular and Cellular Biochemistry

Paramyxoviruses, pneumoviruses, and other non-segmented negative sense (NNS) RNA viruses have historically been of public health concern. Although their genomes are typically small (up to 19kbs) they are able to inflict large-scale detrimental pathologies on host cells. Human metapneumovirus (HMPV) is a widespread pathogen and is a NNS RNA virus. HMPV results respiratory tract infections and is particularly dangerous for preterm infants, the elderly, and immunocompromised individuals. Other viruses within the NNS RNA virus order include the deadly Ebola, Hendra, and Nipah viruses (EBOV, HeV, and NiV), as well as the re-emerging measles virus (MeV). Despite their public impact, there …

Pneumovirus Infections: Understanding Rsv And Hmpv Entry, Replication, And Spread, Jonathan T. Kinder

Theses and Dissertations--Molecular and Cellular Biochemistry

Pneumoviruses including human metapneumovirus (HMPV) and respiratory syncytial virus (RSV) are significant causes of respiratory tract infections globally. Children, elderly, and immunocompromised patients are at the greatest risk for developing severe infections, which can have devastating outcomes. Although these viruses are ubiquitous with significant impacts on human health, there are no antivirals or vaccines available. The only FDA approved therapy is a monoclonal antibody for RSV, given prophylactically during the infectious season, and this treatment is only available for high risk infants. The work presented in this thesis aims to increase our understanding of how these viruses enter, replicate, and …

Mechanisms Of Therapeutic Resistance In Castration Resistant Prostate Cancer, Sarah Katherine Martin

Theses and Dissertations--Molecular and Cellular Biochemistry

Taxane based chemotherapy is an effective treatment for castration-resistant prostate cancer (CRPC) via stabilization of microtubules. Progression to castration-resistant prostate cancer is characterized by increased androgen receptor (AR), elevated intra-prostatic androgens and activated AR signaling despite castrate levels of androgens.

Previous studies identified that the inhibitory effect of microtubule targeting chemotherapy on AR activity was conferred by interfering with AR intracellular trafficking. The N-terminal domain (NTD) of AR was identified as a tubulin interacting domain that can be effectively targeted by the novel small molecular inhibitor, EPI. Taken together, this evidence provided the rationale that targeting AR nuclear translocation and …

Heterogeneity In Platelet Exocytosis, Deepa Jonnalagadda

Theses and Dissertations--Molecular and Cellular Biochemistry

Platelet exocytosis is essential for hemostasis and for many of its sequelae. Platelets release numerous bioactive molecules stored in their granules enabling them to exert a wide range of effects on the vascular microenvironment. Are these granule cargo released thematically in a context-specific pattern or via a stochastic, kinetically-controlled process? My work describes platelet exocytosis using a systematic examination of platelet secretion kinetics. Platelets were stimulated for increasing times with different agonists (i.e. thrombin, PAR1-agonist, PAR4-agonist, and convulxin) and micro-ELISA arrays were used to quantify the release of 28 distinct α-granule cargo molecules. Agonist potency directly correlated with the speed …

Proteasome Regulation Of Caspase-8: Significance In Cancer, Michael Vincent Fiandalo

Theses and Dissertations--Molecular and Cellular Biochemistry

Anti-tumor therapeutic strategies based on combinations of chemotherapeutic agents with a death inducing ligand such as TNF-α Related Apoptosis Inducing Ligand (TRAIL), are directed towards selective and effective cancer cell apoptosis and enhanced therapeutic response. We previously demonstrated that proteasome inhibition sensitizes TRAIL resistant prostate cancer cells to TRAIL-mediated apoptosis via stabilization of the active p18 subunit of initiator caspase-8. The present study investigated the functional link between caspase-8 and the proteasome, by analyzing the impact of caspase-8 ubiquitination and proteasomal degradation on the outcomes of the extrinsic apoptosis pathway in cancer cells. Caspase-8 ubiquitination status was assessed by polyubiquitin …

Identification Of Sumoylated Proteins And Investigation Of Protein Ubiquitination In The Nf-Κb Pathway, Xiaoyan Liu

Theses and Dissertations--Molecular and Cellular Biochemistry

SUMOylation and ubiquitination are important post-translational modifications. While ubiquitination is well known for targeting proteins for degradation, SUMOylation often regulates the intracellular localization of substrates. In the first project of this dissertation, we developed proteomic strategies to identify novel SUMOylated proteins in mammalian cells. In the second project, we investigated the regulation of protein ubiquitination in the NF-κB signaling pathway in the context of Paget’s disease of bone (PDB).

Identification of SUMOylated proteins has been a challenge because of low abundance of SUMOylation substrates. Here, we utilized a mass spectrometry (MS)-based proteomic approach to identify novel SUMOylated proteins in mammalian …

Rit Gtpase Signaling Mediates Oxidative Stress Resistance And Survival Of Adult Newborn Neurons After Traumatic Brain Injury, Weikang Cai

Theses and Dissertations--Molecular and Cellular Biochemistry

The small GTPases function as molecular switches to control diverse signaling cascades. The mammalian Rit and Rin, along with Drosophila Ric, comprise an evolutionarily conserved subfamily of the Ras-related GTPases. Previous studies using cultured cell models suggested that Rit was involved in the control of cell proliferation, transformation, neuronal differentiation, morphogenesis, and cell survival, but the principal physiological function of Rit remained uncharacterized.

To address this outstanding question, we employed a genetic approach, engineering a Rit knockout mouse. Using this animal model, we demonstrate a central role of Rit in governing cell survival in a p38-dependent fashion. Primary mouse embryonic …