Viral pathogens, especially those that undergo rapid mutagenesis, pose a significant threat to public health. Viruses that exemplify this issue include influenza, HIV, and Ebola. Given the low efficacy of seasonal vaccines for influenza, our project focuses on improving existing influenza vaccinations. Instead of using conventional methods, such as injecting inactivated pathogens or viral subunits, mRNA sequences encoding the viral hemagglutinin (HA) fused to our recently-developed self-assembling I53-dn5 nanoparticle platform will be administered in vivo. The organized array of the protein platform can lead to stronger B-cell crosslinking and a robust immune response. However, characterization of I53-dn5 in vitro is critical before use in vaccination studies. My work focused on optimizing the expression, secretion, and assembly of the I53-dn5 protein platform. To mimic in vivo conditions, I transfected DNA encoding HA-fused I53-dn5 into HEK293F cells. Past experiments have shown that when dn5A and dn5B are transfected separately, they express at disproportional concentrations. To resolve this, we encoded both components onto one DNA plasmid for transfection. However, with this new approach, we also needed to cleave the two components after expression. To do so, we incorporated different cleaving peptides, such as T2A and Furin cleavage sites. Through western blots, SDS page electrophoresis, SCC protein purification, and electron microscopy, I analyzed how these cleaving peptides impacted assembly and secretion of the protein platform. Once we are able to consolidate an effective model, we will be able to start in vivo studies. Furthermore, if effective, our model can be used to create vaccinations against other viral illnesses, including HIV and coronavirus.

Natural proteins often assemble into various complex geometric structures based on their interactions with each other. The King Lab at the University of Washington's Institute for Protein Design uses the way these proteins behave to develop computational models that enable the design of novel self-assembling protein cages, or nanoparticles. The designed particles are capable of holding and transporting molecules or displaying antigens on their surface, making them effective vaccine candidates. My project involves recovering the solubility of one of these protein cages known as T33_dn2. T33_dn2 is a tetrahedral protein cage comprised of four copies each of two trimeric components known as T33_dn2A and T33_dn2B. While both components can be expressed individually through E.coli before being assembled in vitro, they can also be expressed bicistronically and assemble in vivo. Currently, the use of T33_dn2 as a vaccine scaffold is limited because T33_dn2B is insoluble, and only seems to be stabilized in solution when associating with T33_dn2A. When expressed bicistronically, however, the cage has an extremely low yield. For a protein to be developed into a vaccine, it must be soluble. To recover the solubility and yield of T33_dn2B, I am testing ten plasmid variants of bicistronic T33_dn2. The “original” plasmid consists of one gene coding for a high-expressing cleavable SUMO protein attached to T33_dn2A and another coding for T33_dn2B. The additional nine variants have single point mutations at specific locations on the T33_dn2A gene intended to affect binding strength. After expression, introducing wildtype T33_dn2A in vitro will allow for the formation of T33_dn2. I will be presenting the results of these expression, purification, and assembly tests.

Cannabinoids, the main constituents of Cannabis, are a class of highly abused compounds of which, Δ-9-tetrahydrocannabinol (THC) is the primary psychoactive molecule. Despite the wide use of THC, its metabolism in humans is still in need of greater understanding. THC is metabolized to 11-OH-THC and sequentially to 11-COOH-THC by cytochrome P450 enzymes (CYPs) 2C9 and 2C19. 11-COOH-THC is then further conjugated to form 11-COOH-THC-glucuronide by UDP-glucuronosyltransferases (UGTs) 1A1 and 1A3. THC and its subsequent metabolites have been shown to bind to liver-type fatty acid binding protein (FABP1). FABPs are intracellular lipid binding proteins (iLBPs) that regulate the homeostasis of their endogenous ligands by solubilizing these hydrophobic compounds in the cytosol. Knockout of FABP1 in mouse hepatocytes was shown to decrease the formation and clearance of 11-OH-THC while the metabolism of 11-COOH-THC appeared to be unaffected. The goal of the current investigation is to translate these results into the human liver. Previously, our lab expressed and purified human FABPs to test their effect on THC metabolism in incubation assays with human liver microsomes (HLMs) and recombinant enzymes. After initiating the THC reaction with the CYP cofactor, NADPH, the 11-OH-THC product was extracted and quantified using LC-MS/MS. We found that both FABP and albumin changed the metabolic rate of THC in an enzyme specific manner. Because 11-OH-THC formation was altered in the presence of FABPs compared to the HSA control, we extend this method to continue our investigation with 11-COOH-THC metabolism. Considering that UGTs are on the luminal rather than the cytosolic side of the endoplasmic reticulum and that 11-COOH-THC has greater water solubility, we expect to observe enzyme and substrate specific effects of FABP. 11-COOH-THC and 11-COOH-THC-glucuronide are biological markers of THC metabolism so understanding this metabolic pathway is important for developing better methods of characterizing THC use in humans.

More than 442 million people worldwide have been diagnosed with diabetes, many of which regulate their glucose levels using the pump/catheter system. However, just 2-3 days after the catheter is inserted into the body, the tissue clogs due to the foreign body reaction (FBR), an immune reaction elicited by the body in response to any foreign material injected in the body. At this point, the patient must remove the catheter and insert a new device into fresh skin elsewhere, resulting in excess scar tissue. Our project focuses on preventing the FBR by reducing its triggering event--protein attachment--so that insulin catheters can last longer (2-3 weeks) and can reduce fibrotic accumulation in patients. To combat the frequency of delivery site changes, we have designed a nonfouling zwitterionic polymeric brush coating for the surface of the catheter to reduce protein attachment. For the coating, zwitterionic sulfobetaine methacrylate (SBMA) was surface-polymerized onto the catheter using atom transfer radical polymerization (ATRP). SBMA has been shown to resist protein adsorption down to less than 1ng/cm². The ATRP initiator was plasma-deposited to robustly adhere to the unique geometry of the catheter. In this work, we used a full factorial design of experiment (DOE) to determine significant experimental factors to the polymerization protocol to maximize the amount of SBMA on the surface. The coating was characterized using x-ray photoelectron spectroscopy (XPS) to confirm the presence of SBMA and the radiolabeled protein adsorption assay to measure the amount of protein adsorbed to the coating. We plan to use the results of the DOE screening to further optimize the nonfouling coating and ultimately plan to test this coating on insulin-delivering catheters in a diabetic mouse model to observe sustained lowered blood sugar levels and histologically review the extent of the FBR through collagen accrual.