Medical Biochemistry Commons^™

Complex Interplay Of Kinetic Factors Governs The Synergistic Properties Of Hiv-1 Entry Inhibitors., Koree W. Ahn, Michael J. Root

Department of Biochemistry and Molecular Biology Faculty Papers

The homotrimeric HIV-1 envelope glycoprotein (Env) undergoes receptor-triggered structural changes that mediate viral entry through membrane fusion. This process is inhibited by chemokine receptor antagonists (CoRAs) that block Env-receptor interactions and by fusion inhibitors (FIs) that disrupt Env conformational transitions. Synergy between CoRAs and FIs has been attributed to a CoRA-dependent decrease in the rate of viral membrane fusion that extends the lifetime of the intermediate state targeted by FIs. Here, we demonstrated that the magnitude of CoRA/FI synergy unexpectedly depends on FI-binding affinity and the stoichiometry of chemokine receptor binding to trimeric Env. For C-peptide FIs (clinically represented by …

Decorin-Evoked Paternally Expressed Gene 3 (Peg3) Is An Upstream Regulator Of The Transcription Factor Eb (Tfeb) In Endothelial Cell Autophagy., Thomas Neill, Catherine Sharpe, Rick T. Owens, Renato V. Iozzo

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Macroautophagy is a fundamental and evolutionarily conserved catabolic process that eradicates damaged and aging macromolecules and organelles in eukaryotic cells. Decorin, an archetypical small leucine-rich proteoglycan, initiates a protracted autophagic program downstream of VEGF receptor 2 (VEGFR2) signaling that requires paternally expressed gene 3 (PEG3). We have discovered that PEG3 is an upstream transcriptional regulator of transcription factor EB (TFEB), a master transcription factor of lysosomal biogenesis, for decorin-evoked endothelial cell autophagy. We found a functional requirement of PEG3 for TFEB transcriptional induction and nuclear translocation in human umbilical vein endothelial and PAER2 cells. Mechanistically, inhibiting VEGFR2 or AMP-activated protein …

The Kinetic Mechanism Of Bacterial Ribosome Recycling., Yuanwei Chen, Akira Kaji, Hideko Kaji, Barry S. Cooperman

Department of Biochemistry and Molecular Biology Faculty Papers

Bacterial ribosome recycling requires breakdown of the post-termination complex (PoTC), comprising a messenger RNA (mRNA) and an uncharged transfer RNA (tRNA) cognate to the terminal mRNA codon bound to the 70S ribosome. The translation factors, elongation factor G and ribosome recycling factor, are known to be required for recycling, but there is controversy concerning whether these factors act primarily to effect the release of mRNA and tRNA from the ribosome, with the splitting of the ribosome into subunits being somewhat dispensable, or whether their main function is to catalyze the splitting reaction, which necessarily precedes mRNA and tRNA release. Here, …

Structural Basis For Selective Inhibition Of Cyclooxygenase-1 (Cox-1) By Diarylisoxazoles Mofezolac And 3-(5-Chlorofuran-2-Yl)-5-Methyl-4-Phenylisoxazole (P6)., Gino Cingolani, Andrea Panella, Maria Grazia Perrone, Paola Vitale, Giuseppe Di Mauro, Cosimo G G. Fortuna, Roger S. Armen, Savina Ferorelli, William L. Smith, Antonio Scilimati

Department of Biochemistry and Molecular Biology Faculty Papers

The diarylisoxazole molecular scaffold is found in several NSAIDs, especially those with high selectivity for COX-1. Here, we have determined the structural basis for COX-1 binding to two diarylisoxazoles: mofezolac, which is polar and ionizable, and 3-(5-chlorofuran-2-yl)-5-methyl-4-phenylisoxazole (P6) that has very low polarity. X-ray analysis of the crystal structures of COX-1 bound to mofezolac and 3-(5-chlorofuran-2-yl)-5-methyl-4-phenylisoxazole allowed the identification of specific binding determinants within the enzyme active site, relevant to generate structure/activity relationships for diarylisoxazole NSAIDs.

Additional Sex Combs Interacts With Enhancer Of Zeste And Trithorax And Modulates Levels Of Trimethylation On Histone H3k4 And H3k27 During Transcription Of Hsp70., Taosui Li, Jacob W Hodgson, Svetlana Petruk, Alexander Mazo, Hugh W Brock

Department of Biochemistry and Molecular Biology Faculty Papers

BACKGROUND: Maintenance of cell fate determination requires the Polycomb group for repression; the trithorax group for gene activation; and the enhancer of trithorax and Polycomb (ETP) group for both repression and activation. Additional sex combs (Asx) is a genetically identified ETP for the Hox loci, but the molecular basis of its dual function is unclear.

RESULTS: We show that in vitro, Asx binds directly to the SET domains of the histone methyltransferases (HMT) enhancer of zeste [E(z)] (H3K27me3) and Trx (H3K4me3) through a bipartite interaction site separated by 846 amino acid residues. In Drosophila S2 cell nuclei, Asx interacts with …

Extending The S-Benzimidazolyl (Sbiz) Platform: N-Alkylated Sbiz Glycosyl Donors With The Universal Activation Profile, Scott Hasty, Nigam Rath, Alexei Demchenko

Chemistry & Biochemistry Faculty Works

This article describes the development of alkylated S-benzimidazolyl (SBiz) imidates as versatile building blocks for chemical glycosylation. The SBiz imidates have been originally developed as a new platform for active-latent glycosylations and its utility was further extended to other common strategies for oligosaccharide synthesis. This article expands upon the utility of these compounds. We developed a general protocol for the synthesis of a series of N-alkylated SBiz glycosides from N-protected SBiz aglycones by Lewis acid-mediated coupling with glucose pentaacetate. The N-alkylated SBiz moiety was found to be stable under strong basic conditions which allowed us to obtain both armed and …

Effect Of Extracellular Survivin And Lymphoma Exosomes On Natural Killer Cells, Heather R. Ferguson Bennit

Loma Linda University Electronic Theses, Dissertations & Projects

Tumors alter their microenvironment to promote survival using methods such as angiogenesis promotion, growth signals, and immune suppression. The immune system becomes unresponsive to transformed neoplastic cells through a variety of methods including T cell suppression, increased myeloid-derived suppressor cells (MDSCs), and reduced natural killer (NK) cell activity. NK cells have inherent killing capabilities and thus are among the first responders in recognizing and destroying abnormal cells. However, many types of cancers inhibit the surveillance and cytotoxic abilities of NK cells by releasing exosomes, vesicles that can modulate the tumor microenvironment (TME) and intercellular communication for the purpose of enhancing …

The Role Of Vegf And Smooth Muscle Phenotype In Hypoxic Remodeling Of Ovine Carotid And Cerebral Arteries, Margaret C. Hubbell

Loma Linda University Electronic Theses, Dissertations & Projects

Arteries are a dynamic tissue with multiple cell types that incorporate systemic and local factors to maintain homeostasis. Hypoxia stimulates capillary angiogenesis to effectively match metabolic demand with perfusion. With chronic hypoxia, vascular remodeling of even large vessels can occur. This predisposes to pathologic states as seen with atherosclerosis, hypoxic brain injury, myocardial ischemia, diabetes, and developmental anomalies. With this remodeling comes changes in vessel structure including medial thickness and organization of contractile proteins as well as changes in myogenic tone. All of these factors culminate in changes in status or behavior of the vascular smooth muscle within the vessel …

Traceable Peo-Poly(Ester) Micelles For Breast Cancer Targeting: The Effect Of Core Structure And Targeting Peptide On Micellar Tumor Accumulation, Shyam M. Garg, Igor M. Paiva, Mohammad R. Vakili, Rania Soudy, Kate Agopsowicz, Amir H. Soleimani, Mary Hitt, Kamaljit Kaur, Afsaneh Lavasanifar

Pharmacy Faculty Articles and Research

Traceable poly(ethylene oxide)-poly(ester) micelles were developed through chemical conjugation of a near-infrared (NIR) dye to the poly(ester) end by click chemistry. This strategy was tried for micelles with poly(ε-caprolactone) (PCL) or poly(α-benzyl carboxylate-ε-caprolactone) (PBCL) cores. The surface of both micelles was also modified with the breast cancer targeting peptide, P18-4. The results showed the positive contribution of PBCL over PCL core on micellar thermodynamic and kinetic stability as well as accumulation in primary orthotopic MDA-MB-231 tumors within 4–96 h following intravenous administration in mice. This was in contrast to in vitro studies where better uptake of PEO-PCL versus PEO-PBCL micelles …

Instrumental Aspects Of Oxygen Sensing: Quantitation And Recalibration Of A Biofouled Oxygen Sensor, Marlena Patrick

Graduate Theses and Dissertations

In vivo oxygen sensing is a critical area of research for medical applications, such as ischemic stroke, but this important topic is not fully understood or resolved. In addition, the best method for calibration of in vivo sensors is as yet undetermined. For all implantable devices, biofouling, the adsorption of biological material to the device surface, is another significant problem with no clear or well-defined solution. One method employed is to apply a protective polymer membrane to the sensor surface in order to minimize the adsorption of biological material. The work described here investigates two polymers applied to a gold …

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 …

Optimizing Heart Failure Outcomes Through Diet: A Review, Farley B. Neasman Iii

Marshall Journal of Medicine

Heart failure is a growing epidemic that will add significant monetary and human costs to an already overtaxed health-care system. Though promising new medications have recently been approved, this complex condition is largely preventable through aggressive risk factor modification, with diet being shown to have a greater effect than exercise. An underrated component of a healthy diet is the simple addition of nuts – the anti-inflammatory fatty acids, healthy proteins, and general availability have been shown to improve survival and reduce the primary risk factors contributing to heart failure, making the addition of nuts and legumes to the diet an …

Functional Selectivity Of Gpcr-Directed Drug Action Through Location Bias., Roshanak Irannejad, Veronica Pessino, Delphine Mika, Bo Huang, Philip B. Wedegaertner, Marco Conti, Mark Von Zastrow

Department of Biochemistry and Molecular Biology Faculty Papers

G-protein-coupled receptors (GPCRs) are increasingly recognized to operate from intracellular membranes as well as the plasma membrane. The β 2 -adrenergic GPCR can activate G s -linked cyclic AMP (G s -cAMP) signaling from endosomes. We show here that the homologous human β 1 -adrenergic receptor initiates an internal G s -cAMP signal from the Golgi apparatus. By developing a chemical method to acutely squelch G-protein coupling at defined membrane locations, we demonstrate that Golgi activation contributes significantly to the overall cellular cAMP response. Golgi signaling utilizes a preexisting receptor pool rather than receptors delivered from the cell surface, requiring …

A Delayed H3k27me3 Accumulation After Dna Replication Of Embryonic Stem Cells Opens Chromatin For Lineage Specific Transcription Factors To Bind And Initiate Differentiation, Jingli Cai, Svetlana Petruk, Robyn Sussman, Sina K. Kovermann, Samantha Mariani, Bruno Calabretta, Steven B Mcmahon, Hugh W. Brock, Lorraine Iacovitti, Alexander Mazo

Department of Neuroscience Faculty Papers

Introduction

Pluripotent stem cells (PSCs) have been useful to generate differentiated progenies for cell replacement therapy, and disease models. The Parkinson’s Disease (PD) field was arguably one of the first to have embraced the promise of stem cells. However, regardless of the differentiation protocols used, cultures and grafts continue to contain multiple cell types with midbrain dopamine (mDA) neural progenitors (NPs) and neurons representing only a fraction of total cells in the dish or graft. During cell differentiation, recruitment of transcription factors (TFs) to repressed genes in euchromatin is essential to activate new transcriptional programs, which is impeded by condensed …

A Novel Population Of Cardiovascular Progenitors Persist In Neonates As Mesendodermal Cells, Julia Kim

Loma Linda University Electronic Theses, Dissertations & Projects

The rise in mortality due to cardiovascular disease has increased the need to develop an efficient regenerative therapeutic for heart failure. Numerous cell-based therapies have been investigated for myocardial regeneration; however, an optimal progenitor has yet to be discovered. Identifying a resident cell population with enhanced ability to differentiate into multiple lineages would greatly contribute to the field of stem cell-based regenerative therapy. Evidence suggests that endogenous cardiovascular progenitor cells (CPCs) that have been isolated from the heart itself express ISL1, KDR, and MESP1, and are capable of differentiating into all major cardiac lineages. The earlier developmental stage at which …

Targeting Ledgf/P75 To Sensitize Chemoresistant Prostate Cancer Cells To Taxanes, Leslimar Rios-Colón

Loma Linda University Electronic Theses, Dissertations & Projects

Prostate cancer (PCa) is the second most diagnosed cancer in males. This disease disproportionately affects African American men, with a higher incidence and mortality compared to other ethnic/racial groups. An aging male population and the complexity of addressing the health disparities associated with this disease puts PCa into the spotlight due to its serious public health implications and the imminent fiscal challenge over the next decades. Chronic prostate inflammation resulting in activation of stress and prosurvival pathways contribute to disease progression and the development of chemoresistance. Lens epithelium-derived growth factor p75 (LEDGF/p75) is a stressresponse protein that promotes cellular survival …

The 11s Proteasomal Activator Regγ Impacts Polyglutamine-Expanded Androgen Receptor Aggregation And Motor Neuron Viability Through Distinct Mechanisms., Jill M. Yersak, Heather L. Montie, Erica S. Chevalier-Larsen, Yuhong Liu, Lan Huang, Martin Rechsteiner, Diane E. Merry

Department of Biochemistry and Molecular Biology Faculty Papers

Spinal and bulbar muscular atrophy (SBMA) is caused by expression of a polyglutamine (polyQ)-expanded androgen receptor (AR). The inefficient nuclear proteasomal degradation of the mutant AR results in the formation of nuclear inclusions containing amino-terminal fragments of the mutant AR. PA28γ (also referred to as REGγ) is a nuclear 11S-proteasomal activator with limited proteasome activation capabilities compared to its cytoplasmic 11S (PA28α, PA28β) counterparts. To clarify the role of REGγ in polyQ-expanded AR metabolism, we carried out genetic and biochemical studies in cell models of SBMA. Overexpression of REGγ in a PC12 cell model of SBMA increased polyQ-expanded AR aggregation …

Structure Activity Relationship Studies Of Novel Diarylpentanoid Analogs Targeting The Androgen Receptor In Prostate Cancer Cells, Haili Coffin, Marco Bisoffi

Student Scholar Symposium Abstracts and Posters

The development of prostate cancer (PCa) relies strongly on the activation of the androgen receptor (AR) signaling pathway by its natural ligand dihydrotestosterone. Furthermore, PCa progression to metastatic disease represents oncogene addiction to AR activity. Androgen ablation therapy is thus a mainstay therapy against this disease, but the development of ligand-independent AR activation and persisting AR expression eventually leads to castration resistant PCa (CRPC). Therefore, down-regulation of AR expression in PCa cells may be an effective therapeutic modality. The diarylpentanoid ca27 has previously been shown to down-regulate AR expression by an unknown mechanism of action. The present work represents a …

Diagnostic Effectiveness Of High-Sensitivity Troponins, Sean R. Bodin, Jacqueline Ramirez

Physician Assistant Capstones, 2016 to 2019

Background: Acute myocardial infarctions (AMI) are a leading cause of death in the United States. The key to increasing survivability is early recognition to expedite the proper treatment modalities. In conjunction with the clinical presentation and electrocardiograms, the use of cardiac biomarkers is exponentially important in not only recognizing a cardiac event but also determining the extent of injury. Advancement in laboratory technology has led to the development of high-sensitive troponin (hs-troponin) assays which can detect smaller cardiac troponin serum levels compared to conventional troponin assays. This implies that the use of hs-troponin assays is more effective in the …

Kinetic Studies Of Dna Repair Enzyme Alkbh2, Michael R. Vittori

Senior Honors Projects

The genomes of living organisms are under constant bombardment from various sources, including chemical modification stemming from processes within the organisms themselves or from exogenous agents, and from radiation. These sources of genomic damage may induce structural changes in the genome’s most basic functional units, the nucleotides that comprise DNA. Damage to an organism’s DNA may result in the production of dysfunctional or nonfunctional proteins. Failure to repair such damage may result in the compounding of successive mutations within the organism’s genome, the pathogenesis of cancer and various genetic disorders in humans. To ensure their viability, organisms have developed unique …