Biochemistry, Biophysics, and Structural Biology Commons^™

Mechanistic Investigations Of A Novel Braf Regulatory Switch And Braftide, An Allosteric Peptide Inhibitor Of Braf, Alison Yu

Theses and Dissertations

RAF kinases (ARAF/BRAF/CRAF or Raf-1) are serine/threonine kinases in the MAPK (RAS-RAF-MEK-ERK) pathway. The MAPK pathway is crucial in development and normal cell function. These same roles are dysregulated in cancer; BRAF is the most frequently mutated isoform in cancers and in particular, activation loop mutants BRAF V600E/K mutants have the highest mutational incidence. Three FDA approved inhibitors potently inhibit BRAF V600E/K mutants. However, these same inhibitors fail to address the non-V600E/K mutations and result in paradoxical activation of the MAPK pathway. Two strategies were employed to address the limitations of the FDA-approved inhibitors: provide novel regulatory details of RAF …

Profiling And Verifying The Substrates Of E3 Ubiquitin Ligase Rsp5 In Yeast Cells, Shuai Fang, Geng Chen, Yiyang Wang, Rakhee Ganti, Tatiana A Chernova, Li Zhou, Savannah E Jacobs, Duc Duong, Hiroaki Kiyokawa, Yury O Chernoff, Ming Li, Natalia Shcherbik, Bo Zhao, Jun Yin

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Yeast is an essential model organism for studying protein ubiquitination pathways; however, identifying the direct substrates of E3 in the cell presents a challenge. Here, we present a protocol for using the orthogonal ubiquitin transfer (OUT) cascade to profile the substrate specificity of yeast E3 Rsp5. We describe steps for OUT profiling, proteomics analysis, in vitro and in cell ubiquitination, and stability assay. The protocol can be adapted for identifying and verifying the ubiquitination targets of other E3s in yeast. For complete details on the use and execution of this protocol, please refer to Wang et al.

Modeling Biphasic, Non-Sigmoidal Dose-Response Relationships: Comparison Of Brain- Cousens And Cedergreen Models For A Biochemical Dataset, Venkat D. Abbaraju, Tamaraty L. Robinson, Brian P. Weiser

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Biphasic, non-sigmoidal dose-response relationships are frequently observed in biochemistry and pharmacology, but they are not always analyzed with appropriate statistical methods. Here, we examine curve fitting methods for “hormetic” dose-response relationships where low and high doses of an effector produce opposite responses. We provide the full dataset used for modeling, and we provide the code for analyzing the dataset in SAS using two established mathematical models of hormesis, the Brain-Cousens model and the Cedergreen model. We show how to obtain and interpret curve parameters such as the ED50 that arise from modeling, and we discuss how curve parameters might change …

Invited Review: Adrenocortical Function In Avian And Non-Avian Reptiles: Insights From Dispersed Adrenocortical Cells., Rocco V. Carsia, Patrick J. Mcilroy, Henry B John-Alder

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Herein we review our work involving dispersed adrenocortical cells from several lizard species: the Eastern Fence Lizard (Sceloporus undulatus), Yarrow's Spiny Lizard (Sceloporus jarrovii), Striped Plateau Lizard (Sceloporus virgatus) and the Yucatán Banded Gecko (Coleonyx elegans). Early work demonstrated changes in steroidogenic function of adrenocortical cells derived from adult S. undulatus associated with seasonal interactions with sex. However, new information suggests that both sexes operate within the same steroidogenic budget over season. The observed sex effect was further explored in orchiectomized and ovariectomized lizards, some supported with exogenous testosterone. Overall, a suppressive effect of testosterone was evident, especially in cells …

Role Of Chronic Stress-Induced Neuroinflammation In Rodent Locus Coeruleus Physiology And Anxiety-Like Behaviors, Arthur Anthony Alfonso Reyes

Graduate School of Biomedical Sciences Theses and Dissertations

The locus coeruleus (LC), the primary site of brain norepinephrine (NE), is a key anatomical brain region implicated in the stress response. Stress is a neuroendocrine physiologic response to a stressor that promotes organism survival through adaptive change and restoration of homeostasis. The central stress response, which drives behavioral and physiological change, is primarily mediated by activating the hypothalamic-pituitary-adrenal (HPA) axis. While advantageous in the short term, chronic stress exposure can lead to HPA axis and LC dysregulation, which are thought to contribute to the etiology of anxiety disorders. Previous studies demonstrate the effects of acute stress in increasing LC …

Artemisinin And Its Derivatives Reactions: Characterization Of The Reaction Products Using Lc/Tof Ms, Kogila Vijayan

Theses and Dissertations

Artemisinin (ART) is a sesquiterpene lactone and a popular malaria drug with potential anticancer properties. In this work, LC/TOF MS was used to investigate the reaction of ART with DNA bases and estradiol. ART-deoxyadenosine and ART-deoxycytidine interactions were studied in the presence of Fe (II) ions. ART-deoxyadenosine and ART-deoxycytidine reaction mixtures gave chromatographic signatures that remained unchanged at room temperature but grew after incubation at 37°C. The change in temperature from room temperature to 37°C was the main driver of adduct formation in these reactions. ART was found to react with Fe (II) ions as observed from several new chromatographic …

The Involvement Of Ubiquitin In Med13 Cyclin C Degradation Following Cellular Stress, Ayesha Gurnani, Brittany Friedson, Katrina Cooper

Rowan-Virtua Research Day

The Cdk8 Kinase Module is a dissociable regulator of cellular stress response genes, with degradation of its components Med13 and cyclin C eventually determining cell fate decisions such as engaging cell survival or cell death mechanisms. We aimed to explore the roles of ubiquitin in degradation of the Cdk8 Kinase Module following nitrogen starvation, with respect to the potential involvement of deubiquitinating enzyme Doa4, lysine linkage at position K63, and E2 ubiquitin conjugating enzymes Ubc4 and Ubc5. We utilized Western blot analysis to observe nitrogen starvation-induced degradation of Med13-HA in wild-type, doa4 mutant, and K63R yeast strains; degradation of cyclin …

Identifying Co-Factors That Drive Tra-1 Activator Function, Jibran Imtiaz, Yongquan Shen, Ronald Ellis

Rowan-Virtua Research Day

Gli proteins are involved in cell fate determination, proliferation, and patterning in many species and are major effectors of Hedgehog (Hh) signaling. There are three Gli proteins in humans, and mutations or errors in their regulation lead to a variety of developmental disorders or cancer. However, the mechanisms by which they interact with co-factors are poorly understood. We are analyzing co-factors of Gli proteins using TRA-1 in Caenorhabditis nematodes. The TRA-1 zinc fingers are structurally like those of other Gli proteins, and TRA-1 can be cleaved like other Gli proteins to form a repressor. However, its function has changed during …

Immunomodulatory Effects Of Resolvin D2 In A Model Of Infection, Prem Yugandhar Kadiyam Sundarasivarao

Graduate School of Biomedical Sciences Theses and Dissertations

Dysregulated hyperinflammatory host immune response to underlying bacterial infections is a characteristic of sepsis. In sepsis, bacteria often trigger abnormal hyperinflammatory responses which can cause multiple organ failure and if sustained can lead to an immunosuppressive phase where the host is susceptible to secondary infections caused by opportunistic bacteria like Pseudomonas aeruginosa (P. aeruginosa). In our studies, we used a 2-hit model of cecal ligation and puncture (CLP) followed by P. aeruginosa secondary lung infection to investigate cellular and molecular mechanisms in the beneficial action of resolvin D2 (RvD2). Resolvins of the D-series are a group of fatty acids known …

The Effects Of Specialized Pro-Resolving Mediator Lipoxin A4 On Pseudomonas Aeruginosa Biofilms And Interactions With Monocytes, Julianne M. Thornton

Graduate School of Biomedical Sciences Theses and Dissertations

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen known as a major cause of hospital-acquired secondary infections, commonly causing chronic respiratory infections in immunocompromised individuals, especially those with cystic fibrosis, and often found in wound infections. P. aeruginosa uses the quorum sensing pathway to readily form protective biofilms, which reduce the efficacy of antibiotics and access by host immune cells to eradicate the pathogen. Specialized pro-resolving mediators (SPMs) are lipids endogenously produced by the host immune response to infection to aid in infection resolution. One SPM, Lipoxin A4 (LxA4), has been shown to be a robust quorum sensing inhibitor.

The …

Modeling The Tripartite Role Of Cyclin C In Cellular Stress Response Coordination, Steven J. Doyle

Graduate School of Biomedical Sciences Theses and Dissertations

For normal cellular function, exogenous signals must be interpreted and careful coordination must take place to ensure desired fates are achieved. Mitochondria are key regulatory nodes of cellular fate, undergoing fission/fusion cycles depending on the needs of the cell, and help mediate cell death fates. The CKM or Cdk8 kinase module, is composed of cyclin C (CC), Cdk8, Med12/12L, and Med13/13L. The CKM controls RNA polymerase II, acting as a regulator of stress-response and growth-control genes. Following stress, CC translocates to the mitochondria and interacts with both fission and iRCD apoptotic mediators. We hypothesize that CC represents a key mediator, …

Investigating The Antibacterial And Immunomodulatory Properties Of Lactobacillus Acidophilus Postbiotics, Rachael M. Wilson

Graduate School of Biomedical Sciences Theses and Dissertations

Probiotics are nonpathogenic microorganisms that have been extensively studied for their ability to prevent various infectious, gastrointestinal, and autoimmune diseases. The mechanisms underlying these probiotic effects have not been elucidated. However, we and other researchers have evidence suggesting that probiotic bacteria secrete metabolites that are antimicrobial and anti-inflammatory. As such, we developed a methodology to collect the secreted metabolites from a probiotic bacterium, Lactobacillus acidophilus, and tested this cell free filtrate (CFF) both in vitro and in vivo. Using this CFF, we have demonstrated that L. acidophilus secretes a molecule(s) that has specific bactericidal activity against the opportunistic pathogen, Pseudomonas …

Med13 Degradation Defines A New Receptor-Mediated Autophagy Pathway Activated By Nutrient Deprivation, Sara E. Hanley

Graduate School of Biomedical Sciences Theses and Dissertations

Cells are exposed to an enormous amount of diverse extracellular cues but have a limited arsenal of weapons for protecting and maintaining homeostasis. To overcome these restrictions, nature has engineered proteins that have multiple functions. The pleiotropy of using one protein to carry out a variety of functions allows cells to rapidly execute tailored responses to a diverse set of signals. The Cdk8 kinase module (CKM) is a conserved detachable unit of the Mediator complex predominantly known for its role in transcriptional regulation. The CKM is composed of four proteins, the scaffolding proteins Med13 and Med12, as well as the …

Stabilizing G-Quadruplex Dna And Rna Structures With Ionic Liquids, Timothy Vaden

College of Science & Mathematics Departmental Research

Stabilizing DNA and RNA for long-term room-temperature storage is important for many biotechnological applications including oncology pharmaceuticals and mRNA-based vaccines (e.g. Covid vaccines). This poster shows that ionic liquids can improve the thermal stability of G-quadruplex DNA and RNA structures, and motivates further studies of ionic liquid-based materials for DNA / RNA stabilization.

Anterior And Posterior Tongue Regions And Taste Papillae: Distinct Roles And Regulatory Mechanisms With An Emphasis On Hedgehog Signaling And Antagonism., Archana Kumari, Charlotte M. Mistretta

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Sensory receptors across the entire tongue are engaged during eating. However, the tongue has distinctive regions with taste (fungiform and circumvallate) and non-taste (filiform) organs that are composed of specialized epithelia, connective tissues, and innervation. The tissue regions and papillae are adapted in form and function for taste and somatosensation associated with eating. It follows that homeostasis and regeneration of distinctive papillae and taste buds with particular functional roles require tailored molecular pathways. Nonetheless, in the chemosensory field, generalizations are often made between mechanisms that regulate anterior tongue fungiform and posterior circumvallate taste papillae, without a clear distinction that highlights …

Ultrasound-Assisted Air-Jet Spinning Of Silk Fibroin-Soy Protein Nanofiber Composite Biomaterials., Futian Yang, Fang Wang, Janine Mazahreh, Xiao Hu

College of Science & Mathematics Departmental Research

Ultrasound utilizes a non-radiation technology that can meet modern standards to gain access to cheap, reliable and sustainable modern energy. Ultrasound technology can be implemented in the field of biomaterials for its exceptional potential in controlling the shape of nanomaterials. This study presents the first example of the production of soy and silk fibroin protein composite nanofibers in various ratios via combining ultrasonic technology with air-spray spinning. Characterization of ultrasonic spun nanofibers was performed by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric (TG) analysis, water contact angle, water retention, enzymatic …

Dpc29 Promotes Post-Initiation Mitochondrial Translation In Saccharomyces Cerevisiae, Kyle A. Hubble, Michael F. Henry

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Mitochondrial ribosomes synthesize essential components of the oxidative phosphorylation (OXPHOS) system in a tightly regulated process. In the yeast Saccharomyces cerevisiae, mitochondrial mRNAs require specific translational activators, which orchestrate protein synthesis by recognition of their target gene's 5'-untranslated region (UTR). Most of these yeast genes lack orthologues in mammals, and only one such gene-specific translational activator has been proposed in humans-TACO1. The mechanism by which TACO1 acts is unclear because mammalian mitochondrial mRNAs do not have significant 5'-UTRs, and therefore must promote translation by alternative mechanisms. In this study, we examined the role of the TACO1 orthologue in yeast. We …

Dpc29 Promotes Mitochondrial Translation Post-Initation In Saccharomyces Cerevisiae, Kyle Andrew Hubble

Graduate School of Biomedical Sciences Theses and Dissertations

Although the cytosolic and bacterial translation systems are well studied, much less is known about translation in mitochondria. In the yeast Saccharomyces cerevisiae, mitochondrial gene expression is predominately regulated by translational activators. These regulators are thought to promote translation by binding the elongated 5’-UTRs on their target mRNAs. Since mammalian mitochondrial mRNAs generally lack 5’-UTRs, they must regulate translation by other mechanisms. As expected, most yeast translational activators lack orthologues in mammals. Recently, a mitochondrial gene-specific translational activator, TACO1, was reported in mice and humans. To better define its role in mitochondrial translation I examined the yeast TACO1 orthologue, DPC29. …

Dual Mechanisms Implemented By Lin-28 For Positive Regulation Of Hbl-1 Are Necessary For Proper Development Of Distinct Tissues In Caenorhabditis Elegans, Madeleine Minutillo

Graduate School of Biomedical Sciences Theses and Dissertations

In Caenorhabditis elegans, the heterochronic pathway is comprised of a hierarchy of genes that control the proper timing of developmental events. hbl-1 (Hunchback Like-1) encodes an Ikaros family zinc-finger transcription factor that promotes the L2 stage cell fate events of the hypodermis. The downregulation ofhbl-1 is a crucial step for the transition from the L2 to the L3 stage. There are two known processes through which negative regulation of hbl-1 occurs: suppression of hbl-1 expression by 3 let-7 miRNAs through the hbl-1 3’UTR and inhibition of HBL-1 activity by LIN-46. The mechanisms by which hbl-1 is positively regulated have not …

The Effects Of Stress On The Mammalian Nucleolus And Ribosome Synthesis, Russell T. Sapio

Graduate School of Biomedical Sciences Theses and Dissertations

Ribosomes are responsible for translating every protein in the cell and are essential in all domains of life. Ribosome biosynthesis (RB) takes place in the nucleolus and is an intricate hierarchical process involving over 200 factors, including ribosomal proteins, ribosomal RNA (rRNA), and trans-acting ribosome biogenesis factors (RBFs). Inhibiting RB can disrupt nucleolar integrity, causing ribosomal- and nucleolar-factors to delocalize. This can stabilize the transcription factor p53, which is normally degraded rapidly, ultimately causing cell cycle arrest or apoptosis, through a mechanism termed the nucleolar stress response (NSR). This thesis explores the effects of inhibiting RB post rRNA transcription and …

A Conserved Mechanism For Hormesis In Molecular Systems, Sharon N. Greenwood, Regina G. Belz, Brian P. Weiser

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Hormesis refers to dose-response phenomena where low dose treatments elicit a response that is opposite the response observed at higher doses. Hormetic dose-response relationships have been observed throughout all of biology, but the underlying determinants of many reported hormetic dose-responses have not been identified. In this report, we describe a conserved mechanism for hormesis on the molecular level where low dose treatments enhance a response that becomes reduced at higher doses. The hormetic mechanism relies on the ability of protein homo-multimers to simultaneously interact with a substrate and a competitor on different subunits at low doses of competitor. In this …

Morphine-Induced Hyperactivity Is Attenuated By Intra-Accumbens Administration Of The Highly-Selective Dopamine D3 Receptor Antagonist Vk4-40, Mansi Patel, Desta M. Pulley, Daniel Manvich

Rowan-Virtua Research Day

Opioids exert their abuse-related effects by enhancing dopamine (DA) neurotransmission within the brain’s mesolimbic reward system, a neural projection involving DA neurons in the ventral tegmental area (VTA) that project to medium spiny neurons within the nucleus accumbens (NAc). Mu (MOR) are expressed by several populations of GABAergic neurons that tonically inhibit VTA DA neurons. By inhibiting these GABAergic neurons in a MOR-dependent manner, opioids indirectly enhance DA neurotransmission via disinhibition of DAergic neurons. Accumulating evidence indicates that selective pharmacological antagonism of the dopamine D3 receptor (D3R) attenuates the abuse-related effects of several opioids, but the neurobiological mechanisms mediating this …

Effect Of Uracil Dna Glycosylase Activity On The Efficacy Of Thymidylate Synthase Inhibitor/Hdac Inhibitor Combination Therapies In Colon Cancer, Rashmi Kulkarni, Brian P Weiser

Rowan-Virtua Research Day

Human uracil DNA glycosylase (UNG2) is responsible for removing uracil bases from DNA and initiates base excision repair pathways. Accumulation of uracil or its fluorinated analogs in DNA is one of the killing mechanisms of thymidylate synthase (TS) inhibitors in cancer cells, and depletion of UNG2 often enhances the toxicity of these anticancer drugs. We tested the effect of UNG2 KO on the efficacy of multiple TS inhibitors (5-fluorouracil, fluorodeoxyuridine, and pemetrexed) and we determined that, except for 5-fluorouracil, all other TS inhibitors were significantly more potent in UNG2 KO cells compared to wild-type HT29 cells. Interestingly, UNG2 protein levels …

Differentiating The Mechanistic Role And Chemotherapeutic Potential Of Src And Podoplanin In Oncogenic Transformation, Edward P. Retzbach

Graduate School of Biomedical Sciences Theses and Dissertations

There were an estimated 20 million new cancer cases worldwide in 2020, resulting in nearly 1000 deaths per hour [1]. Oral cancer exemplifies the difficulties of treating cancer patients. The first line for oral cancer treatment is surgery and radiation that can lead to patient disfigurement and decreased quality of life in cancer survivors [2-4]. Though there have been many developments in chemotherapy in the last 30 years, the 50% mortality rate associated with oral cancer has not changed [4, 5]. Longitudinal studies that track survival rates in oral cancer patients demonstrate a 3-fold reduction in patient deaths when patients …

Contact Normalization And The Role Of Maackia Amurensis Seed Lectin As A Novel Chemotherapeutic And Antiviral Agent, Stephanie A. Sheehan

Graduate School of Biomedical Sciences Theses and Dissertations

Cells communicate with each other to coordinate tissue function and homeostasis. Diseases including cancer, arthritis, and acute respiratory disease syndrome (ARDS) require a breakdown in this intercellular communication. For example, cancer progression is suppressed by junctional communication between nontransformed and transformed cells. This process is called contact normalization. Junctional communication must be disrupted to enable transformed cells to grow into malignancies. However, the junctions and mechanisms by which nontransformed cells normalize cell behavior have not been clearly defined. My project aimed to identify junctions and elucidate mechanisms underlying contact normalization. We discovered that cadherins, specifically N-cadherin, form junctions that enable …

Investigations In The Cellular And Molecular Biology Of Human Airway Mucociliary Tissue, Vincent Manna

Graduate School of Biomedical Sciences Theses and Dissertations

Our laboratory has integrated the use of a human-derived, in vitro model of airway mucociliary tissue. We isolate human nasal epithelial cells (HNECs) from the nasal mucociliary tissue of donors with a small brush and expand the airway progenitor cells in culture. The HNECs are then seeded onto semi-permeable transwell inserts. The inserts are in contact with the media in the lower chamber but don’t contain media in the upper chamber therefore the cells are exposed to the air while drawing nutrients from the media below, this is called the Air-Liquid Interface (ALI). HNECs cultured at the ALI initiate a …

Effects Of Trans-Acting Factors On The Translational Machinery In Yeast, Brandon M. Trainor

Graduate School of Biomedical Sciences Theses and Dissertations

Synthesis of proteins, or translation, is a complex biological process requiring the coordinated effort of numerous protein and RNA factors. Central to translation is the ribosome, a complex macromolecular complex consisting of both ribosomal RNA (rRNA) and ribosomal protein (r-protein). Ribosomes are essential and are one of the oldest and most abundant biomolecules across all forms of life. In addition to the ribosome, translation requires messenger RNA (mRNA), transfer-RNA conjugated to an amino acid (aa-tRNA), translation factors, and energy in the form of ATP and GTP. Translation universally occurs in four major stages, initiation, elongation, termination, and recycling, with initiation …

Safety Of Silver Oxide Coated Biomaterials In Mice, Michael Klug, Darien L. Seidman, Rahyan Mahmoud, Destiny Morot, Lei Yu, Jeffrey D Hettinger, Renee M Demarest

Rowan-Virtua Research Day

It has been demonstrated that silver oxide coatings designed by our collaborators are able to prevent E. coli and P. aeruginosa attachment to biomaterials in vivo. These findings demonstrate that such coatings show promise in preventing the development of biofilm on biodevices. However, it is unknown if the use of silver oxide in this fashion is toxic in vivo. The goal of this project was to determine whether our silver oxide coatings are safe to use in vivo. To assess the toxicity of our silver oxide formula, mice were implanted with either silver oxide coated titanium discs or uncoated titanium …

Replication Protein A (Rpa) Targeting Of Uracil Dna Glycosylase (Ung2), Derek Chen, Brian P Weiser

Rowan-Virtua Research Day

Replication Protein A (RPA) is a single stranded DNA binding protein which stabilizes ssDNA for replication and repair. One function of RPA is to bind the DNA repair enzyme uracil DNA glycosylase (UNG2) and direct its activity towards ssDNA dsDNA junctions.

UNG2 removes uracil bases from DNA which can appear through dUMP misincorporation or through cytosine deamination. If uracil is present instead of a cytosine, then the original GC pair becomes a GU pair. The uracil will then base pair to adenine in the replicated daughter strand. This results in a GC → AT mutation that could contribute to cancer …

Substrate-Dependent Modulation Of Sirt2 By A Fluorescent Probe, 1-Aminoanthracene, David Bi, Prashit Parikh, Jie Yang, Brian P Weiser

Rowan-Virtua Research Day

Sirtuin isoform 2 (SIRT2) is an enzyme that catalyzes the removal of acyl groups from lysine residues. SIRT2’s catalytic domain has a hydrophobic tunnel where its substrate acyl groups bind. Here, we report that the fluorescent probe 1-aminoanthracene (AMA) binds within SIRT2’s hydrophobic tunnel in a substrate-dependent manner. AMA’s interaction with SIRT2 was characterized by its enhanced fluorescence upon protein binding (>10-fold). AMA interacted weakly with SIRT2 alone in solution (Kd = 37 μM). However, when SIRT2 was equilibrated with a decanoylated peptide substrate, AMA’s affinity for SIRT2 was enhanced ∼10-fold (Kd = 4μM). The peptide’s decanoyl chain and …