• Characterization of Proton Sensitive G protein-Coupled Receptors

      Nam, Alisha; Okasha, Najeah; Spencer, Angela; Lambert, Nevin; Biological Sciences; Department of Pharmacology and Toxicology; Chemistry and Physics; Spencer, Angela; Augusta University (1/31/2020)
      G protein-coupled receptors (GPCRs) are membrane-bound receptors that can stimulate an intracellular signaling pathway following activation by a ligand. According to the International Union of Basic and Clinical Pharmacology (IUPHAR) database, GPR4, GPR65, and GPR132 are Class A orphan GPCRs with protons reported as their putative endogenous ligand; however, these receptors are currently understudied. After confirming whether these receptors are pH-sensitive, the purpose of our study was to investigate the interactions between GPR4, GPR65 and GPR132 and G protein subtypes (G?s, G?i, G?q, and G?12) upon stimulation with an acidic solution. Using bioluminescence resonance energy transfer (BRET), we studied the coupling between luciferase-tagged GPR receptors and fluorescent protein (Venus)-tagged G proteins in response to pH changes. Data indicated that all three receptors responded to pH changes. Upon extracellular response to pH changes, the receptors activate different G protein subtypes and thus, different signaling pathways: GPR4 activates G?i, G?q, and G?12; GPR65 activates all four subtypes; and GPR132 activates G?i�and weakly activates G?q, and G?12. Identifying these receptors as true proton sensors leads the way in understanding the role they play in maintaining acid-base homeostasis and will be critical for the development of novel drugs combatting acid-base related disorders.
    • DEVELOPMENT OF AN ALTERNATIVE SYNTHETIC PATHWAY TO NYLON 6,6 THROUGH THE USE OF SOLAR IRRADIATION AS THE SOLE HEAT SOURCE

      Hammond, Caroline; Agee, Brian M.; Chemistry and Physics; Agee, Brian M; Augusta University (1/29/2020)
      Recently, scientists have attempted to transform traditional synthetic procedures into ones that are more environmentally favorable due to the desire to circumvent the damage being done to our environment. A technique was recently developed in which satellite dishes were repurposed as solar reflectors that are capable of providing a focused source of solar irradiation.� The ability to use the solar reflector as the sole heat source for synthetic reactions has been analyzed for the synthesis of the commercially important polyamide, nylon 6,6.� Commercially, Nylon 6,6 is synthesized using a multi-step procedure, in which nearly all of the steps require the addition of heat in order for the reaction to occur.� Furthermore, the synthesis also incorporates some chemicals/reagents that are not environmentally friendly or consist of elements that are considered endangered and supply are in serious danger.� The exchange of these reagents with more environmentally friendly, sustainable substitutes has been analyzed for the total synthesis of nylon 6,6.� The incorporation of a solar energy heat source and use of environmentally friendly chemicals provides a new synthetic route to nylon6,6 that can be taught in teaching labs as a �green synthesis� experiment or scaled to fit the needs of industrial synthesis.
    • Investigating Signaling Pathways Involving the HCA Receptor Family

      Saj, Dalia; Spencer, Angela; Okashah, Najeah; Lambert, Nevin; Biological Sciences; Chemistry and Physics; Department of Pharmacology and Toxicology; Spencer, Angela; Augusta University (1/31/2020)
      Increasing obesity rates have put the American population at higher risk for developing obesity-related medical conditions such as hypertension, heart disease, and diabetes. The hydroxycarboxylic acid (HCA) receptor family is a family of G protein-coupled receptors (GPCRs) that are expressed in adipose tissue and function as metabolic sensors, making them potential pharmaceutical targets in the treatment of obesity and other metabolic disorders. The HCA receptor family consists of the HCA1, HCA2, and HCA3�receptors, which are activated by hydroxycarboxylic acids such as lactate and 3-hydroxybutyric acid. We utilized bioluminescence resonance energy transfer (BRET) to study agonist-induced coupling of luciferase-tagged HCA receptors to Venus fluorescent protein-tagged G protein heterotrimers or arrestins. Our results indicate that the three HCA receptors couple to the Gi/o�subfamily of G proteins. The data additionally confirms a lack of coupling to the other G protein subfamilies (Gs,�Gq,�and G12), and lacks evidence of arrestin recruitment to HCA receptors. Overall, our study highlights the use of BRET as a powerful tool for analysis of GPCR signaling and demonstrates its possible use for future studies to determine the potency of potential drugs targeting HCA receptors as a therapy for health-related problems such as obesity.
    • Ionic and Covalent Conjugates of Metronidazole and Tryptamine

      Lyons, Dominique; Baako, Precious; Lebedyeva, Iryna; Chemistry and Physics; Lebedyeva, Iryna; Augusta University (2/2/2020)
      Metronidazole, is an antibiotic used in the treatment of many bacterial and parasitic infections. This antibacterial agent has been shown to have a variety uses upon its development. Metronidazole is derived synthetically from Azomycin, a natural antimicrobial antibiotic produced by actinobacteria such as Norcadia mesenterica, Sterptomyces eurocidicus and proteobacrteria Pseudomonas fluorescens used to treat anaerobic parasitic and bacterial infections. Solid drugs are not as effective in the body because they are not solube enough to allow for effectve release into circulation making it hard for the body to absorb. However, ionic liquids can be used to improve drug delivery, efficay and development. Ionic liquid compositons are typically made up of at least two different ions with atleast one kind of cation and one kind of anion. In this project ionic liquid compositions containing metronidazole as positively charged ion and acesulfame as counterion have been synthesized. To explore the brain-penetrating ability of tryptamine, we have created its conjugates with beta-alanine, glucine and gabapentin. These ionic and conavelnt conjugates represent existing drugs with improved properties such as palatability and lipophilicity.